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CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. patent application Ser. No. 09/738,975, filed Dec. 18, 2000, abandoned.
This application claims the priority of German Patent Application No. 199 60 626.9 filed Dec. 16, 1999, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to an internal-combustion engine having a gas inlet port that is subdivided into at least two partial ports by a partitioning wall extending over at least a portion of the length of the port.
In piston-type internal-combustion engines, it is known from, for example, WO 95/17589 and DE-A-198 03 867, to subdivide at least the cylinder port that is connected to the gas-intake valve of each cylinder into two partial ports, over at least part of the port length, using at least one partitioning wall. A control device is provided at the beginning of the partitioning wall, when seen in the flow direction, for at least one of the two partial ports. This device can influence the volume flow that flows through this partial port. Thus, it is possible to purposefully guide the flow through at least one of the partial ports and to a segment of the valve-gap region of the gas-intake valve, and to change the distribution of the air mass or charge mass flowing into the cylinder by throttling the other partial current. Because the distribution of the charge mass via the valve gap dictates the creation of turbulence in the cylinder, the throttling of at least one of the partial ports can control the turbulence formation and intensity in the cylinder. At the same time, it is possible to influence the extent of the mixing of the different charge components. Hence, the mass distribution onto the upper and lower valve-gap regions can be influenced. If a larger proportion of the mass is conducted through the upper valve-gap region, a tumbling effect is created in the cylinder. This tumbling can have a positive effect on combustion and, if desired, permits a stable stratification between the air and fuel and/or the exhaust gas. If the lower partial port is closed, the turbulence also effects a favorable combustion behavior with low engine loads (partial load). With a full load, however, no intensive turbulence is supposed to be generated—in other words, both partial ports should remain open.
For structural reasons, the first partial port, which is preferably the upper one, is connected to the fuel supply such that, for example, a fuel-injection nozzle discharges into this partial port. Depending on the operating mode, if the lower partial port is closed or slightly open, the fuel-air mixture flows through the upper, first partial port and is predominantly guided to the upper valve-gap region. The charge mass supplied to the lower valve-gap region is increased in proportion to the increase of the supply of air or exhaust gas from the exhaust-gas return via the second, lower partial port, so the turbulence formation in the cylinder is reduced corresponding to the increase in the gas flow through the second partial port. If the distribution of the charge mass being conducted through the gas intake onto the two partial ports is controlled, this can infinitely variably influence the intensity of the tumbling. This is also a function of a piston-type internal-combustion engine with direct fuel injection.
A corresponding structural embodiment of the port partition, and/or the selection of the time of the fuel supply (injection time), can have a positive impact on the mixing of the fuel-air mixture or the exhaust gas-fuel-air mixture. The mixture can be intensively mixed (homogeneous mixture) or distinctly stratified. This construction further permits the introduction of exhaust gas into at least one partial port and, depending on the throttling of the other partial port, a more or less defined stratification of the exhaust gas-air-fuel mixture. In an arrangement involving a plurality of intake valves per cylinder, it is possible to provide a common intake region for all of the intake valves, in which the partitioning wall that subdivides the intake port ends, or to allow each intake valve of a cylinder to exert its own influence through a corresponding division into two parallel ports, beginning from a common port part. In the latter case, the partitioning wall effecting a corresponding division extends from the common port area into the region of the two parallel ports, so the end of the partitioning wall can also be brought closely to the valve gap of the relevant intake valve.
It is also known from WO 95/17589 to cast the partitioning wall with corresponding casting cores in the production of the cylinder head, or to place a corresponding structural element comprising a different material, such as a stamped steel sheet, into the casting mold and embed it into the cylinder head.
It is the object of the invention to improve a piston-type internal-combustion engine of the aforementioned type, with respect to the embodiment of its cylinder ports, particularly the gas intake ports.
SUMMARY OF THE INVENTION
In accordance with the invention, the above object generally is achieved with a piston-type internal-combustion engine having at least one cylinder port, which essentially discharges into a cylinder via at least one throughgoing opening, per cylinder. This port is divided, at least over a part of its length, into at least two partial ports by at least one partitioning wall that has a profile with flow channels extending in the flow direction on one surface of the wall. It is preferable for the divisional plane that is defined by the partitioning wall to be oriented essentially transversely to the cylinder axis.
In contrast to the known, smooth-surface embodiment of the partitioning walls, the profile with the flow channels in accordance with the invention offers the option of also profiling the mass flow transversely to its flow direction, that is, to create “strands” with a higher mass-flow density, so the mass flow traversing the relevant partial port is shaped accordingly. With two essentially parallel troughs or flow channels that are disposed at least in the vicinity of the throughgoing opening, for example, it is possible to provide two partial flows that have an increased mass flow, particularly for the upper partial port, and to guide these flows past both sides of the valve stem, which passes through the end region of the intake port, in order to avoid turbulence or an undesired diversion of the mass flow toward the edge. With a corresponding embodiment of the trough or flow channel shape, it is also possible for the main component of the mass flow to be diverted more strongly toward the center of the cylinder, or toward the cylinder wall, depending on the embodiment of the combustion chamber.
While it is possible in principle to provide this type of flow channel shape with respect to the two partial ports, for example, in the form of a wavy cross-section of the partitioning wall, it can be advantageous to allocate the trough shape to only one partial port, for example the upper partial port, while the partitioning wall for the other partial port has a level or flat surface.
A wavy cross-sectional shape of the partitioning wall is advantageous both for a partitioning wall that is cast with the cylinder head and for a partitioning wall that is cast as a separate component, particularly as a separate piece of sheet steel, because the changes in spacing that occur due to thermal expansions caused by different temperature levels can be readily accommodated, and ruptures in the partitioning wall or a loosening of the partitioning wall from the casting material can be avoided. The concept of the invention is not, however, limited to a cast or embedded partitioning wall. A partitioning wall that is inserted later, for example as a steel sheet, into cast slots in the port side wall is technically advantageous, but also solves structural problems that are caused by different thermal expansions.
The invention is described in detail below using schematic drawings of exemplary embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical, partial sectional view of the cylinder head region with a gas intake port according to the invention and a gas intake valve and with one partial port closed.
FIG. 2 is the arrangement according to FIG. 1 with both partial ports open to show the different partial flows.
FIG. 3 is a cross-section through a partial port along the line III in FIG. 1 to illustrate one embodiment of the partitioning wall according to the invention.
FIG. 4 is a cross-section similar to that of FIG. 3, with a modified embodiment of a partitioning wall.
FIG. 5 shows a modification of the embodiment according to FIG. 1 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a partial cutout view of a cylinder head 1 of a piston-type internal-combustion engine. In the drawing described below, the engine is provided with an intake valve 2 for each cylinder, with the valve 2 opening and closing an intake opening 3 leading to an engine cylinder. The intake opening 3 is associated with an intake port 4 , that is divided by a partitioning wall 5 into a first partial port 4 . 1 and a second partial port 4 . 2 in the illustrated embodiment. The partitioning wall 5 extends with its divisional plane transversely to the axis 6 of the cylinder, and its end edge 7 ends directly in front of the stem 8 of the intake valve 2 . As can be seen in FIG. 5, the partitioning wall 5 can also be provided in its end region with a recess 13 to form a pair of tongues 5 . 1 that extend laterally on either side of the stem 8 of the intake valve 2 . The end edges 7 . 1 of the partitioning-wall tongues 5 . 1 formed by this arrangement can be extended as shown, closely up to the region of the intake opening 3 .
The intake port 4 , whose partitioning wall 5 forms an angle with the cylinder axis 6 , ends in an intake region 9 that is formed by a curved region oriented essentially downward into the cylinder, and is limited by the intake opening 3 .
The arrangement is also basically applicable to a plurality of intake valves 2 associated with a cylinder. In this case, either two throughgoing, parallel or mirror-symmetrical intake ports are provided for each intake valve, or a central port part is divided like a fork and guided with two corresponding, parallel ports up to the associated gas intake valves. In this embodiment, the partitioning wall 5 also extends with a corresponding fork-like division into the fork-shaped parallel ports. The term “parallel ports” is not to be understood in strict adherence to the geometrical concept, but encompasses all structures in which corresponding intake ports are associated with a plurality of intake valves.
The injection nozzle, which is not shown in detail here, but is indicated by the arrow 10 , discharges into the first partial port 4 . 1 , so a fuel-air mixture is conducted into the cylinder via the partial port 4 . 1 . The partial port 4 . 2 is charged with air, an exhaust gas-air mixture, an air-fuel mixture, an exhaust gas-air-fuel mixture, or with recirculated exhaust gas, so the mixtures being conducted through the two partial ports 4 . 1 and 4 . 2 can be mixed at the earliest at the point where they flow together in the intake region 9 .
The lower partial port 4 . 2 is provided with a device 11 for changing the free flow cross-section, for example, a throttle valve 11 , which is actuated as a function of the desired load state of the piston-type internal-combustion engine.
FIGS. 1 and 2 illustrate the different flow directions of the gas flow conducted through the intake port 4 for different opening positions of the throttle valve 11 . The different settings of the throttle valve 11 serve to influence the mass distribution onto the upper valve-gap region 4 . 3 and the lower valve-gap region 4 . 4 as indicated in FIG. 2 . If a larger proportion of the mass passes through the upper valve-gap region 4 . 3 , as is the case, for example, when the throttle valve 11 is partially closed, tumbling occurs in the cylinder of the engine. This tumbling can have a favorable effect on the combustion and, if desired, can effect a stable stratification between the air and the fuel and/or the exhaust gas. When the lower partial port 4 . 2 is closed, the tumbling also leads to a favorable combustion behavior at low engine loads (partial load). With a full load, no tumbling is supposed to occur; in other words, both partial ports 4 . 1 and 4 . 2 should be open.
If, as shown in FIG. 1, the throttle valve 11 reduces the volume flow through the lower partial port 4 . 2 relative to the volume flow through the upper partial port 4 . 1 , a larger proportion of the total mass is conducted through the upper valve-gap region 4 . 3 into the cylinder than through the lower valve-gap region 4 . 4 . The distribution of the charge masses onto the two valve-gap regions can thus control the intensity of the tumbling occurring in the cylinder.
If the partitioning wall 5 has a level surface, the stem 8 of the intake valve 2 acts as a “spoiler body” for the incoming mass flow, inducing a corresponding separating turbulence at its rear side, when seen in the flow direction.
To improve the flow conditions, the partitioning wall 5 has a profile, at least in the vicinity of the end edge 7 , with at least two flow channels on at least one surface of the partitioning wall 5 . For example, as shown in FIG. 3, the upper surface of the partition wall 5 can be provided with an upward extending separating or guiding body or portion 1 at the end region of the wall 5 opposite the stem 8 , to form flow channels 15 . 1 and 15 . 2 on either side of the stem 8 . This practically divides the main quantity of the air flow guided through the upper partial port 4 . 1 into two partial flows, which are guided past the stem 8 on both sides. The arrangement can be such that the separating body portion 14 is only provided on the side of the partitioning wall 5 facing the upper partial port 4 . 1 , while the lower side of the partitioning wall 5 has a smooth surface as shown, because the turbulence created behind the valve stem 8 has a reduced impact with a full load and a completely open partial port 4 . 2 . However, it is to be understood that both surfaces of the partition wall 5 can be provided with a separating body or portion 14 , if desired.
FIG. 4 shows a modification in which the cross-sectional form of the partitioning wall 5 has a wavy profile with respect to the two partial ports 4 . 1 and 4 . 2 . For the upper partial port 4 . 1 , this profile leads to a trough or channel structure that, due to the upward central wave or undulation 14 ′ that acts as a separating body or portion, conducts the air flow in the partial port 4 . 1 , which is essentially divided into two air flows, in flow channels 15 . 1 ′ and 15 . 2 ′, and past both sides of the valve stem 8 .
The embodiments according to FIGS. 3 and 4 can either extend over only a partial length of the partitioning wall 5 , as in the longitudinal section according to FIG. 1, or over the entire length of the partitioning wall 5 .
As shown in FIG. 3, the partitioning wall 5 with its separating body or portion 14 can be cast or formed as an integral part of the cylinder head. However, particularly when the dual flow channel formed profile extends over the entire length of the partitioning wall 5 , the embodiment according to FIG. 4 has the advantage that it can be placed into the casting core as a separate component, such as a separate sheet element, and its end 16 embedded with the part of the cylinder head that forms the gas-intake port 4 . Thus, various thermal expansions of the cylinder-head material, such as aluminum, and the partitioning-wall material, such as a heat-resistant steel sheet, can be accommodated without difficulty. The wavy structure shown in a cross-section in FIG. 4 offers the advantage of compensating different thermal expansions due to surface temperature variations, even in the case of an embedded partitioning wall 5 .
With a corresponding guidance in the gas-flow direction by the channels formed by the wavy profile of the partitioning wall 5 , depending on the requirements, the flow guided through the gas-intake opening 3 can also be influenced transversely relative to the cylinder. Consequently with a corresponding embodiment and orientation of the channels in the region of the end edge 7 , especially if, as shown in FIG. 5, a corresponding recess is provided in the partitioning wall 5 , the end edge 7 . 1 , in the form of partitioning-wall tongues 5 . 1 , is guided close to the intake region 9 . A corresponding shape of the partitioning-wall tongues 5 . 1 allows a transverse component to be impressed onto the gas flow.
The above-described embodiments of a partitioning wall can also be used in gas exhaust ports if the flow of the exhaust gas is to be improved in the manner of a flow rectification, especially if considerable temperature differences can occur between the partitioning wall and the cooled cylinder-head region surrounding the exhaust port in the region of the gas exhaust ports.
The invention now being fully described, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.
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A piston-type internal-combustion engine having at least one gas intake port ( 4 ) per cylinder, with the port discharging into the cylinder via at least one throughgoing opening ( 3 ). The port is subdivided, over at least a portion of its length, into at least two partial ports ( 4.1, 4.2 ) by at least one partitioning wall ( 5 ). The wall has a profile with a central separating portion on at least one surface being raised relative to the remaining portions of the at least one surface, to divide a flow within an associated partial port ( 4.1, 4.2 ) into two partial flow parts, which extend in the flow direction.
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BACKGROUND
Cube corner reflectors are well-known optical elements that are used in a variety of optical systems. A cube corner reflector 100 as illustrated in FIG. 1 has three planar reflective surfaces 110 , 120 , and 130 that intersect at right angles in the same manner as the intersection of faces at the corner of a cube. Reflective surfaces 110 , 120 , and 130 can be formed on three sides of a tetrahedral glass block that also has a transparent face 140 for input of an incident beam and output of a reflected beam. The tetrahedral glass block in cube corner reflector 100 is symmetric so that the perimeter of transparent face 140 forms an equilateral triangle and the perimeters of reflective surfaces 110 , 120 , and 130 are congruent isosceles right triangles.
Cube-corner reflector 100 is a retroreflector, and therefore a reflected beam from cube-corner reflector 100 is parallel to but offset from an incident beam regardless of the direction of the incident beam. FIG. 1 illustrates an example of an incident beam 180 that enters cube corner reflector 100 through transparent face 140 and reflects from one or more of reflective faces 110 , 120 , and 130 before exiting as a reflected beam 190 . Reflected beam 190 is parallel to incident beam 180 and offset from incident beam 180 by twice the perpendicular separation between incident beam 180 and a vertex 150 of cube corner reflector 100 .
The tetrahedral shape of cube corner reflector 100 includes more glass than is generally required for the optical function of cube corner reflector 100 , particularly in optical systems where the location and direction of the incident beam is well controlled. Cube corner reflector 100 can thus be trimmed to remove glass that is not required for the optical function of cube corner reflector 100 . One conventional way to trim cube corner reflector 100 is to take a cylindrical core of cube corner reflector 100 , which results in transparent face 140 having a circular perimeter. Another known trimming scheme gives transparent face 140 a rectangular boundary 145 .
FIG. 2 shows a cube corner reflector 200 resulting from trimming cube corner 100 at boundary 145 . Cube corner reflector 200 is small for a retroreflector capable of reflecting an incident beam 280 to provide an offset reflected beam 290 . The minimum required size of cube corner reflector 200 to perform this optical function depends on the desired offset between incident and reflected beams 280 and 290 , the diameters or areas of beams 180 and 290 , and the path of the beams inside cube corner reflector 200 . To minimize the area of the face of cube corner reflector 200 , incident beam 280 (or alternatively reflected beam 290 ) is centered at a point on an edge 235 of cube corner reflector 200 .
Analysis of the beam paths in cube corner reflector 200 shows the if incident beam 280 is parallel to a central axis of cube corner reflector 200 then the beam paths will remain within a band having boundaries at the upper and lower edges of beams 280 and 290 in FIG. 2 . For example, a ray 282 at a top edge of incident beam 280 reflects from a reflective face 210 toward a reflective face 230 and then reflects from a point on reflective face 230 that is at the same height as the bottom edge of incident beam 280 . From there, the ray travels horizontally to reflective surface 220 and exits as a reflected ray 292 at the bottom of reflected beam 290 . Similarly, a ray 284 at the bottom of incident beam 280 reflects from reflective surface 230 to a point on reflective surface 210 at the same height as the top of incident beam 280 , travels horizontally to the top of reflected beam 290 , and exits as reflected ray 294 . The height of cube corner reflector 200 can thus be as small as the diameter of beams 280 and 290 plus an added margin for beam variations or misalignments.
FIG. 3 illustrates a known multi-axis plane mirror interferometer 300 employing four cube corner reflectors 200 . U.S. Pat. No. 09/876,531, entitled “Multi-Axis Interferometer With Integrated Optical Structure And Method For Manufacturing Rhomboid Assemblies” further describes some examples of multi-axis interferometers containing retroreflectors that can be implemented using cube corner reflectors.
Interferometer 300 has four input beams IN 1 to IN 4 that are direction into a polarizing beam splitter 310 . Polarizing beam splitter 310 splits input beams IN 1 to IN 4 into components according to polarization. Components of one polarization from input beams IN 1 to IN 4 become respective measurement beams M 1 to M 4 , and components of an orthogonal polarization in input beams IN 1 to IN 4 become reference beams (not shown). Measurement beams M 1 to M 4 travel from polarizing beam splitter 310 to a planar measurement reflector (not shown) that is mounted on an object being measured. The measurement reflector returns measurement beams M 1 to M 4 along the same paths.
Polarization changing elements (e.g., quarter-wave plates) 320 are in the paths of outgoing and returning measurement beams M 1 to M 4 and change the polarization of measurement beams M 1 to M 4 so that polarization beam splitter 310 directs the returning measurement beams M 1 to M 4 to respective cube corner reflectors 200 .
Cube corner reflectors 200 reflect returning measurement beams M 1 to M 4 so that offset measurement beam M 1 ′ to M 4 ′ can traverse polarizing beam splitter 310 and elements 320 , reflect from the measurement reflector, and return through elements 320 and polarizing beam splitter 310 to form parts of respective output beams OUT 1 to OUT 4 . Each measurement axis of interferometer 300 corresponds to a pair of beams M 1 to M 1 ′, M 2 and M 2 ′, M 3 and M 3 ′, or M 4 and M 4 ′ and to a measured point that is halfway between the centers of the incident areas of the corresponding pair on the measurement mirror. Accordingly, cube corner reflectors 200 must be small enough to fit within the spacing of measurement beams M 1 to M 4 and M 1 ′ to M 4 ′ that is required for the desired measurement axes.
The reference beams have paths that include first reflections from a reference reflector (not shown), reflections from respective cube corner reflectors 200 , and second reflections from the reference reflector before the reference beams rejoin respective measurement beams M 1 ′ to M 4 ′ in output beams OUT 1 to OUT 4 . The two reflections of each measurement beam from the measurement reflector, the two reflections of each reference beam from the reference reflector, and the intervening reflections from the associated cube corner reflector 200 are well known to eliminate an angular separation that misalignment of the measurement or reference mirror might otherwise cause between the reference and measurement beams in the combined output beam.
A measurement along a measurement axis of interferometer 300 requires measuring and analyzing the phases of the measurement and reference beams that are within the output beam associated with the measurement axis. These measurements are most accurate if the wavefronts of measurement and reference beams are uniform because the measured phase information is generally an integral or average of the phase information over a cross-section of the output beam. Further, the integrated/analyzed portion of the measurement beam typically changes because of beam “walk-off”. Beam walk-off occurs when the object being measured changes angular orientation. The walk-off changes the matched portions of the measurement and reference beams, causing an erroneous phase shift when the beam wavefront is nonuniform. Wavefront distortion can thus cause errors and lower signal-to-noise ratios in phase information measurements and correspondingly in the measurements along the measurement axes of interferometer 300 .
Returning to FIG. 2, edge 235 of cube corner reflector 200 passes through the center of incident beam 280 . The reflection of a beam from edge 235 is generally nonuniform and distorts the wavefront of the reflected beam. Such non-uniformity may arise from a chamber formed to improve the safety or durability of an otherwise sharp edge and from roll off that commonly arises at the edges of polished optical surfaces. This wavefront distortion can be significant for an interferometer measurement particularly because wavefront distortion from the edge crosses through the center of the beam where light intensity is high.
Another source of wavefront distortion in cube corner reflector 200 arises from reflective surfaces 210 , 220 , and 230 not being perfectly orthogonal. When incident beam 280 is incident on edge 235 , the angular errors in the orientations of reflective surfaces 210 , 220 , and 230 cause the wavefront (i.e., the surface of uniform phase) of output beam 290 to be V-shaped. This V-shape produces measurement errors when measuring a phase for a planar cross-section of the beam. Correcting for this type of wavefront distortion is difficult because expected beam movement relative to edge 235 typically changes which side of the V-shaped wavefront corresponds to the larger portion of beam intensity.
In view of the limitations of current cube corner reflectors, methods and structures that reduce the wavefront distortion caused in reflections from cube corner reflectors could improve measurement signal strength and the accuracy of interferometer measurements.
SUMMARY
In accordance with an aspect of the invention, a cube corner reflector is oriented so that incident and reflected beams either entirely miss the edges at the intersections of reflective surfaces or so that the beams have only peripheral portions incident on the edges. The edges thus cause less wavefront distortion that could affect measurements in systems such as interferometers. With one such orientation, a symmetry plane that is midway between the incident and reflected beams of the cube corner reflector contains one of the edges of the reflective surfaces and a central axis that passes through the vertex of the cube corner reflector. A cube corner reflector having trimmed surfaces perpendicular to its symmetry plane can be closely spaced with other cube corner reflectors to provide a tight beam pattern in a multi-beam device. For minimum size, the trimmed surfaces that are perpendicular to the symmetry plane are at different distances from the central axis.
One specific embodiment of the invention is an optical element such as a cube corner reflector. The optical element has three orthogonal reflective surfaces with three edges at the intersections of the reflective surfaces. A first edge is at an intersection of the first reflective surface and the second reflective surface and is symmetrically located between an incident beam and a reflected beam of the optical element. A second edge is at an intersection of the second reflective surface and the third reflective surface, and a third edge is at an intersection of the third reflective surface and the first reflective surface. A first trimmed surface is parallel to a central plane that contains central rays of the incident and reflected beam.
The optical element may further have a second trimmed surface that is parallel to the first trimmed surface, but the parallel trimmed surfaces are asymmetrically located relative to the central axis through the vertex of the optical element. A perpendicular distance between the first trimmed surface and the central plane differs from a perpendicular distance between the second trimmed surface and the central plane. More specifically, a perpendicular distance between one trimmed surface and the central plane may be required to extend beyond a radius of the incident and reflected beam by at least a distance corresponding to a non-zero deflection of incident beam toward the trimmed surface in the optical element. The beam is deflected away from the other trimmed surface in the optical element so that the distance between that trimmed surface and the central plane can be about equal to the radius of the beams.
Another specific embodiment of the invention is a cube corner reflector. The cube corner reflector includes first, second, and third reflective surfaces, an input/output face, and at least one trimmed surface. The input/output face is perpendicular to a central axis through the vertex of the cube corner reflector and includes a first transparent aperture for an incident beam and a second transparent aperture for a reflected beam. One trimmed face intersects a first edge that is between the first and second reflective surfaces, with the first edge being in a plane that also includes the central axis of the cube corner reflector and passes midway between the first and second apertures.
A second trimmed surface is parallel to the first trimmed surface and is such that a second edge that is between the second and third reflective surfaces makes an angle with the second trimmed surface that is equal to the angle made with the second trimmed surface by a third edge that is between the third and first reflective surfaces. A perpendicular distance between the first trimmed surface and the central axis of the cube corner reflector can be less than a perpendicular distance between the second trimmed surface and the central axis of the cube corner reflector.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a view through the face of a cube corner reflector having a tetrahedral glass body.
FIG. 2 shows a view through the face of a known cube corner reflector having a glass body that is trimmed to provide a rectangular face.
FIG. 3 is a perspective view of a known multi-axis interferometer having a tight beam spacing, which requires uses of trimmed cube corner reflectors.
FIGS. 4A, 4 B, and 4 C are respectively a face-on view, a perspective view, and a side view of a trimmed cube corner reflector in accordance with an embodiment of the invention.
FIG. 5 is a view through the face of a trimmed cube corner reflector in accordance with another embodiment of the invention.
FIG. 6 is a perspective view of a multi-axis interferometer employing cube corner reflectors that are trimmed in accordance with an embodiment of the invention.
FIG. 7 is a perspective view of a trimmed, hollow cube corner reflector in accordance with an embodiment of the invention.
Use of the same reference symbols in different figures indicates similar or identical items.
DETAILED DESCRIPTION
In accordance with an aspect of the invention, trimmed cube corner reflectors that permit tight beam spacing provide minimal distortion of the wavefronts of reflected beams. FIGS. 4A, 4 B, and 4 C respectively show a face-on view, a perspective view, and a side view of a cube corner reflector 400 in accordance with an embodiment of the invention. Cube corner reflector 400 includes a block of optical quality glass such as BK- 7 glass that has three orthogonal reflective surfaces 410 , 420 , and 430 and an input/output face 440 . With the illustrated trimming, reflective surfaces 410 and 420 have the same shape and size, while the shape and size of reflective surface 430 differs from those of reflective surfaces 410 and 420 . Reflective surfaces 410 , 420 , and 430 can be formed using conventional techniques for formation of reflective metal coatings or multi-layer highly reflective dielectric coatings.
Edges 415 , 425 , and 435 between reflective surfaces 410 , 420 , and 430 meet at a vertex 450 through which a central axis 445 of cube corner 400 passes at equal angles to edges 415 , 425 , and 435 . As illustrated in FIGS. 4B and 4C, affordable manufacturing normally does not permit edges 415 , 425 , and 435 to be perfectly sharp, and a sharp edge may be undesirable because of safety and durability concerns. The edges for a precision optical system such as an interferometer thus typically have a chamber about 0.2 mm or smaller when the edge may be in the beam path. A chamfer can be relatively large when the edge is away from the beam path.
Input/output face 440 receives an incident beam 480 and returns a reflected beam 490 that is offset from and parallel to incident beam 480 . (The roles of incident and reflected beams 480 and 490 are reversible, but beam 480 is presumed to be incident beam here for illustration.) Input/output face 440 has transparent apertures that correspond to incident beam 480 and reflected beam 490 , but these apertures may merely be undistinguished areas of input/output face 440 when input/output face 440 is transparent across its entire area. FIG. 1 shows the orientation of input/output face 440 relative to a tetrahedral cube corner 100 .
In addition to optical surfaces 410 , 420 , 430 , and 440 , cube corner 400 also has four trimmed surfaces 441 , 442 , 443 , and 444 that bound input/output face 440 . Trimmed surfaces 441 to 444 can be surfaces that remain after trimming processes cut an originally larger glass block. However, trimmed surfaces are more generally not functional optical surfaces and may be original surfaces that existed before cutting, grinding, and/or polishing processes formed the optical quality surfaces such as reflective surfaces 410 , 420 , and 430 and/or input/output face 440 of cube corner reflector 400 .
Trimmed surfaces 441 to 444 generally can be planar or curved provided that trimmed surfaces 441 to 444 do not cut off any optically required portion of reflective surfaces 410 , 420 , and 430 or of input/output face 440 . Trimmed surfaces 441 to 444 , in a preferred embodiment, are shown as a set of respectively orthogonal and parallel surfaces that are orthogonal to input/output face 440 . Trimmed surfaces 441 to 444 when planar act as convenient part datums for machining and/or other mechanical manufacturing processes.
Cube corner reflector 400 is specifically designed for incident beam 480 to be parallel to and centered a distance X from central axis 445 of cube corner reflector 400 . As a result, the beam path within cube corner 440 is set, and the geometry of cube corner reflector 400 , which controls the location of trimmed faces 441 to 444 , can minimize the size of cube corner 400 for a particular selection of beam size and desired offset. In FIG. 4A, beams 480 and 490 have a radius R and offset X from vertex 450 of cube corner reflector 400 .
Edges 415 , 425 , and 435 are oriented so that a symmetry plane containing edge 415 and central axis 445 of cube corner reflector 400 lies midway between beams 480 and 490 . A perpendicular plane containing the centers of beams 480 and 490 and central axis 445 is above edges 435 and 425 , causing incident beam 480 have a larger portion that initially reflects from surface 410 and a smaller portion that initially reflects from surface 430 . The portion of beam 480 that is incident on edge 435 between reflective surfaces 430 and 410 is at an outer part of beam 480 . Edge 435 thus affects a portion of beam 480 that is shorter than the diameter of beam 280 . In comparison, edge 235 of conventional cube corner reflector 200 passes through a diameter of beam 280 . Edge 435 of cube corner reflector 400 thus affects a smaller portion of incident beam 480 , and for a beam having a Gaussian intensity distribution, edge 435 affects a smaller portion of the integrated power of incident beam 480 . Edge 425 similarly affects the same small, low-intensity portion of the beam at the reflection that produces reflected beam 490 .
The radius R of the clear apertures that accommodate beams 480 and 490 and variations in beams 480 and 490 , a spacing δ between the clear aperture and the optical edge for glass edge imperfections, the desired offset 2X between the centers of beams 480 and 490 , and the beam path in cube corner 400 control the minimum size of cube corner 400 and particularly control the locations or bounds of trimmed surface 441 to 444 . In the direction of the offset, the distance from central axis 445 to trimmed surface 441 or 443 of cube corner reflector 400 must accommodate the separation X between central axis 445 and the center of the beam, a radius R, and spacing δ. Equation 1 thus indicates a minimum width W for cube corner reflector 400 .
W=2(X+R+δ) Equation 1
Central axis 445 and the centers of beams 480 and 490 are closer to trimmed surface 442 than to trimmed surface 444 because of the beam path within cube corner reflector. Reflective surface 410 reflects incident beam 480 toward reflective surface 430 and trimmed surface 444 and away from trimmed surface 442 . Accordingly, a distance Y 1 of trimmed surface 442 from the plane of central axis 445 and the central rays of beams 480 and 490 must accommodate the size of the beam (radius R) and spacing δ. The minimum distance Y 1 is given in Equation 2.
Y 1 =R+δ Equation 2
A distance Y 2 of trimmed surface 444 from the plane of the central axis and central rays of beams 480 and 490 must accommodate the beam's size and movement of the beam toward trimmed surface 444 while still avoiding edge imperfections. FIG. 4A illustrates a ray 482 that is at outer edge (i.e., closest to trimmed surface 441 ) of beam 480 to illustrate the furthest extent of the beam path toward trimmed surface 444 . Surface 410 reflects ray 482 towards reflective surfaces 430 and 420 . The ray 482 reflected from surface 410 strikes surface 430 at a point below the profile of incident beam 480 as viewed in FIG. 4 A. To avoid unacceptable power loss from the beam, distance Y 2 must be large enough to avoid trimming away any of the reflection points of the beam from reflective surface 430 . A geometrical analysis of cube corner reflector 400 indicates that Equation 3 will give the minimum distance Y 2 in terms of separation X, radius R, and spacing δ.
Y 2 =(X+R)tan30°+δ Equation 3
One exemplary embodiment of the invention that provides an offset of 13 mm for an incident beam having a clear aperture diameter of 9 mm with a 2-mm radial allowance for edge imperfections has a total width of about 26 mm. Minimum distance Y 1 is 6.5 mm, and minimum distance Y 2 is about 8.35 mm in this embodiment.
When compared to prior trimmed cube corner reflectors, cube corner reflector 400 causes wavefront distortions that have a smaller effect on interferometer measurements because edges 425 and 435 reflect a small portion of the beam and that small portion has low light intensity.
Trimmed cube corner reflector 400 provides better performance, and particularly less wavefront distortion, than does the conventional trimmed cube corner reflector 200 (FIG. 2) when manufactured with comparable imperfections (e.g., non-orthogonal reflective surfaces, edge roll-off, and chamfer.). In particular, in FIG. 4A, edge 425 and a reflection 435 ′ of edge 435 split the area of reflected beam 490 into three parts. If reflective surfaces 410 , 420 , and 430 are not perfectly orthogonal, each of these parts of reflected beam 490 has uniform phase in a different plane. However, most of the beam intensity is in the central part of reflected beam 490 , even when normal beam movement is taken into account.
The amount or significance of both these types of wavefront distortion depends on the ratio of the beam size to the desired offset. If the desired offset is large relative to the beam diameter, reflection from edges 425 and 435 and the associated wavefront distortions can be completely avoided. FIG. 5, for example, shows a cube corner reflector 500 in which the ratio of the off-axis distance X to the radius R is large enough to avoid reflections from edges 515 , 525 , and 535 between the reflective surfaces 510 , 520 , and 530 . In cube corner reflector 500 , an incident beam 580 is entirely incident on reflective surface 510 . Beam 580 reflects from surface 510 onto an area 585 of reflective surface 530 . The beam then reflects from area 585 onto reflective surface 520 to form output reflected beam 590 . The minimum size of cube corner reflector 500 and particularly the minimum distances between trimmed surfaces 541 , 542 , 543 , and 544 and the central axis of cube corner 500 depend on off-axis beam displacement X, the radius R, the spacing δ for beam variations, and the beam path as described above.
FIG. 6 illustrates multi-axis interferometer optics 600 including multiple cube corner reflectors 400 for respective measurement axes. Interferometer 600 has four input beams IN 1 to IN 4 that are directed into a polarizing beam splitter 310 . As described above in regard to interferometer 300 of FIG. 3 . Polarizing beam splitter 310 splits input beams IN 1 to IN 4 according to polarization into measurement beams M 1 to M 4 and reference beams (not shown). Measurement beams M 1 to M 4 travel from polarizing beam splitter 310 to a planar measurement reflector (not shown) that is mounted on an object being measured. The measurement reflector returns measurement beams M 1 to M 4 , which pass through polarizing beam splitter 310 and enter respective cube corner reflectors 400 . From cube corner reflectors 400 , offset measurement beams M 1 ′ to M 4 ′ follow paths to reflect a second time from the measurement reflector before polarizing beams splitter 310 directs returning offset measurement beams M 1 ′ to M 4 ′ to form parts of output beams OUT 1 to OUT 4 , respectively. The reference beams have paths that similarly include first reflections from a reference reflector (not shown), reflections from respective cube corner reflectors 400 , and second reflections from the reference reflector before the reference beams rejoin respective measurement beams M 1 ′ to M 4 ′ to form output beams OUT 1 to OUT 4 .
The horizontal and vertical spacing of cube corner reflectors 400 match the spacing of measurement beams M 1 to M 4 or M 1 ′ to M 4 ′. Overall system requirements generally dictate this beam spacing, which is required to perform measurements along the desired axes. The trimming of cube corner reflectors 400 allows arrangement of cube corner reflectors 400 in an array that achieves tight beam spacing. When compared to the minimum size of conventional trimmed cube corner reflectors 200 , trimmed cube corner reflectors 400 are generally somewhat larger in the direction perpendicular to the beam offset because the distance Y 2 to one trimmed surface accommodates an internal beam path that departs from the band containing incident and reflected beams. However, cube corner reflectors at the edge of beam arrays can be oriented with distance Y 2 directed out of the beam array, so that the increased size has no effect on beam spacing. In larger arrays (i.e., arrays having three or more cube corner reflectors along the direction perpendicular to the reflection offsets), the increased size is typically acceptable for the required interferometer beam pattern. Thus, for little or no increase in the beam spacing, cube corner reflectors 400 provide less wavefront distortion than do conventional trimmed cube corner reflectors. Analysis of phase information from the beams after reflections from respective cube corner reflectors 400 can thus provide a higher signal-to-noise ratio and more accurate interferometer measurements.
A hollow cube corner reflector in which the paths of the incident and reflected beams are within a hollow portion, rather than within a glass block, can also be trimmed to provide a small size and little or no wavefront distortion. FIG. 7, for example, is a perspective view of a hollow cube corner reflector 700 in accordance with an embodiment of the invention. Cube corner reflector 700 includes orthogonal reflective planar surfaces 710 , 730 , and a surface not shown in the view of FIG. 7 . Reflective planar surfaces 710 and 730 and the reflective surface not illustrate correspond to and have substantially the same shapes as reflective surfaces 410 , 430 , and 420 of cube corner reflector 400 or reflective surfaces 510 , 530 , and 520 of cube corner reflector 500 , so that a front view of cube corner reflector 700 has substantially that same appearance as illustrated in FIG. 4A or FIG. 5 .
Cube corner reflector 700 has a trimmed surface 742 that intersects symmetric reflective surface 710 and the reflective surface (not shown) that is symmetric with reflective surface 710 . Another trimmed surface 744 intersects reflective surface 730 . In accordance with an aspect of the invention, the distance between trimmed surface 742 and the center plane of cube corner reflector 700 can be less than the distance between the center plane and trimmed surface 744 (where trimmed surface 744 intersects reflective surface 730 .) The respective distances can, for example, be as given in Equations 1 and 2. The reduction in the distance between trimmed surface 742 and the center plane allows use of cube corner reflector 700 in systems where the beam spacing does not permit the used of a symmetrically trimmed cube corner reflector.
Although the invention has been described with reference to particular embodiments, the description is only an example of the invention's application and should not be taken as a limitation. In particular, although exemplary embodiments of the invention include cube corner reflectors that are separate optical functions of cube corner reflectors can be integrated into optical elements that also perform other optical functions. Various other adaptations and combinations of features of the embodiments disclosed are within the scope of the invention as defined by the following claims.
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A cube corner reflector is oriented so that incident and reflected beams either entirely miss the edges at the intersections of reflective surfaces or so that the beams have only peripheral portions incident on the edges. A symmetry plane of the cube corner reflector is midway between the incident and reflected beams of the cube corner reflector and contains the central axis of the cube corner reflector and one of the edges between the reflective surfaces. For a minimum size reflector that permits the tight beam spacing, trimmed surfaces perpendicular to the symmetry plane are at different distances from the central axis. The edges, variations in the orthogonality of the reflective surfaces, and beam walk off cause less wavefront distortion that could affect measurements in systems such as interferometers.
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BACKGROUND OF THE INVENTION
Conventionally, to utilize a field-effect liquid crystal display device where the liquid crystals are in the twisted nematic mode, nematic liquid crystals of high positive dielectric anisotropy are utilized. The interior surfaces of the plates constituting the cell which holds the liquid crystal material are each unidirectionally rubbed with a material such as cotton, and the plates are mounted so that the rubbing directions of the opposed plates are at 90° to each other. The molecules immediately adjacent to the inner surfaces of the plates orient themselves in the rubbing directions, and the molecules intermediate the plates form themselves into a helix of one-quarter turn. It is believed that minute grooves are formed by the rubbing and that the liquid crystal molecules fall into the grooves with the molecular axes parallel to the direction of the grooves. Where the rubbing directions, as indicated, are at right angles to each other and the liquid crystal cell is between crossed polarizer plates, then, in the absence of an electric field, light is transmitted through the system. However, if an electric field of sufficient strength is imposed across the cell, utilizing transparent electrodes on the inner surfaces of the cell wall and suitable voltage source connected to said transparent electrodes, then the molecules align themselves with their axes parallel to the imposed field and the optical activity of the liquid crystal material drops to zero. Under such circumstances the crossed polarizing plates prevent any light from passing through the system.
Conventionally, the transparent electrodes do not cover the entire surfaces of the cell plates so that portions of the plates to which the voltage is applied through the use of said electrodes will appear to be dark and opaque while the remainder will be illuminated and transparent. Conversely, if the liquid crystal cell is inserted between polarizers having parallel axes of polarization, that portion of the plates to which the voltage is applied will appear to be illuminated and transparent, and the remainder will be dark and opaque. Generally, the system is mounted so that the polarization axes of the polarizer plates are at 90° to each other, such an arrangement having proved to be the most useful due to the visibility of the display.
Nematic liquid crystals of positive dielectric anisotropy when oriented transverse to the transmission axis of the incident light are birefringent. When the optical axis of the light incident on the liquid crystal layer conforms approximately to the direction of vibration of the incident light, then, in general, the extraordinary beam is the one which is transmitted and used for the display. However, nematic liquid crystals, in general, absorb short-wavelength light so that gradual deterioration and darkening of the liquid crystal material takes place, resulting in decreased visibility of the display provided by the system. It would, therefore, be desirable to eliminate this difficulty.
SUMMARY OF THE INVENTION
A cell is formed of opposing transparent plates, the inner surfaces of each having at least one transparent electrode thereon, each electrode being connectable to an external source of voltage. The interior surface of each of the plates is unidirectionally oriented as by rubbing and the plates are so mounted that the respective rubbing directions are at an angle to each other, preferably at 90° to each other.
Between the plates are nematic liquid crystals. Those liquid crystal molecules immediately adjacent the interior surfaces of said plates orient themselves in the same direction as the orientation of the interior surface of the plate itself. The liquid crystal molecules between the plates form a helix.
The transparent plates of the cell are positioned between a pair of polarizer plates. The polarizer plates are positioned relative to the cell plates so that the transmission axis of each polarizer plate is perpendicular to the orientation of the inner surface of the immediately adjacent cell plate.
The ordering of the liquid crystal molecules in a helix makes the liquid crystal material birefringent. In consequence of the fact that each polarizer plate has its transmission axis perpendicular to the orientation direction of the immediately adjacent cell plate, it is the ordinary beam, rather than the extraordinary beam, which traverses the cell. Experiment has shown that the liquid crystal material absorbs less of the short wave component of the ordinary beam than of the extraordinary beam. Since it is the short-wavelength light which degrades the liquid crystal material, the use of the ordinary beam for the liquid crystal display results in a prolongation of the life of the liquid crystal material and of the device.
Accordingly, an object of the present invention is to prolong the life of the liquid crystal material used in a liquid crystal display device.
A further object to the present invention is a liquid crystal device in which the liquid crystal material is birefringent as well as optically active.
Another object of the present invention is a liquid crystal display device in which the relationship between the transmission axis of a polarizer plate and the orientation of the inner surface of the immediately adjacent cell plate is such that the ordinary beam is transmitted through the cell rather than the extraordinary beam.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.
BRIEF DESCRIPTION OF THE DRAWING
For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:
FIG. 1 represents the transmissivity of birefringent liquid crystals as a function of wavelength for the ordinary and for the extraordinary beam;
FIG. 2 is an edge view of an embodiment of the present invention; and
FIG. 3 is an exploded view in perspective of cell plates and polarizer plates arranged in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As is known, rubbing of cell plates unidirectionally produces an oriented surface, generally believed to be due to the formation of minute grooves. When such plates are to be used as the walls of a cell to contain nematic liquid crystals, each plate has one or more transparent electrodes on the surface thereof which is to be the interior surface when the plates are opposed to form a cell. The transparent electrodes are indicated in FIG. 2 by the reference numerals 21 and 31. The rubbing is done subsequent to formation of electrodes 21 and 31 on cell plates 22 and 32 respectively. In forming a cell for containment of liquid crystals indicated by the reference numeral 19, the plates are mounted so that the rubbing directions on the interior surfaces of the two plates 22 and 32 are at an angle to each other. Preferably, the angle is a right angle.
The liquid crystal molecules adjacent the inner surfaces of plates 22 and 32 fall into the minute grooves on the surfaces thereof and, consequently, orient themselves in the rubbing directions, i.e., align themselves with the grooves. Molecules intermediate the plates align themselves at orientations intermediate the rubbing directions of the two plates. In short, the molecules between the two plates orient themselves in the form of a helix. Where the rubbing directions differ by 90°, the liquid crystal molecules form a quarter-turn helix.
Due to the fact that the molecules are ordered, the liquid crystal material becomes birefringent.
Taking the case where the rubbing directions of plates 22 and 32 are essentially at right angles to each other as shown in FIG. 3, when the liquid crystal cell is placed between crossed polarizer plates, that portion of the cell plates to which the voltage is applied will appear to be dark and opaque, and the remainder will be eliminated and transparent. However, if the liquid crystal cell is placed between polarizers having their polarization axes parallel to each other, that portion of the plates to which the voltage is applied will appear to be illuminated and transparent, and the remainder will be dark and opaque. Of course, the portion of the plates to which the voltage will be applied is that on which there are transparent electrodes as indicated by reference numerals 21 and 31 in FIG. 2
Looking at FIG. 3, it is assumed that incident light arrives at the array of plates from the lower left side. Plane 26 is defined by polarization axis 25 of polarizer plate 24 and optical axis 38 through the system. Plane 27 is defined by rubbing direction 23 on the interior surface of cell plate 22 and the optical axis of the system. If planes 26 and 27 make an angle with each other which is other than 0° or 90° both an extraordinary and an ordinary ray will traverse the cell. However, if planes 26 and 27 are at right angles with each other, then only the ordinary beam will traverse the cell. Similarly, for light approaching the array from the right-hand side, plane 36 is defined by polarization axis 35 of plate 34 and the optical axis of the system and plane 37 is defined by rubbing direction 33 on the interior surface of cell plate 32 and the optical axis of the system. The same conditions apply. If planes 36 and 37 form a right angle, then only the ordinary beam will traverse the cell when light is incident from the right. The same information is presented in FIG. 2 with respect to the relative directions of the polarization axes in the rubbing directions, but, in addition, the fact that the liquid crystal molecules 19 lie in a helix is indicated by the change in apparent length of the molecules in traversing the cell from left to right.
The advantage in having the ordinary beam traverse the cell rather than the extraordinary beam becomes clear from FIG. 1 where curve 12 shows the transmissivity of the ordinary beam as a function of wavelength and curve 11 shows the transmissivity of the extraordinary beam as a function of wavelength. As can be seen from the Figure, absorption of the extraordinary beam by the liquid crystals starts at a larger wavelength than is the case for the ordinary beam. However, the greater the amount of short-wavelength light absorbed, and the larger the wavelength at which absorption starts, the more rapid is the disintegration of the liquid crystals by light energy. Consequently, conventional liquid crystal display devices which utilize the extraordinary beam have relatively weak light-resistance compared to the liquid crystal display device of the present invention which utilizes only the ordinary beam. Moreover, due to the fact that less light is absorbed, the device in accordance with the present invention is brighter and more readily legible at low levels of illumination. The illumination, of course, is in many cases from the exterior. This is particularly the case where such display devices are used in watches which do not have space available for an interior light source and its associated power source and which may be exposed to short-wavelength light as in daylight for long periods of time.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
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A liquid crystal display device utilizes birefringent liquid crystals in a twisted mode in combination with a pair of polarizing plates the system being so mounted that the ordinary beam provides the display. The absorption of short-wavelength light is less for the ordinary beam than for the extraordinary beam, resulting in increased life-expectancy of the liquid crystal material, and therefore of the system.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/381,405, entitled METHOD AND APPARATUS FOR SECURE PRINTING OF TONER-BASED IMAGES, filed May 16, 2002.
FIELD OF INVENTION
The present invention relates to systems and methods for printing and copying documents. More particularly, the invention relates to toner-based imaging systems for printing or copying documents in a secure manner, such that the documents are difficult to forge and original versions of the documents are readily verifiable, and to methods of using and making the system.
BACKGROUND OF THE INVENTION
Toner-based document imaging, such as electrophotographic, iongraphic, magnetographic, and similar imaging techniques, generally involves forming an electrostatic or magnetic image on a charged or magnetized photoconductive plate or drum, brushing the plate or drum with charged or magnetized toner, transferring the image onto a substrate such as paper, and fusing the toner onto the substrate using heat, pressure, and/or a solvent. Using this technique, relatively inexpensive images can be easily formed on a surface of the substrate.
Because toner-based imaging is a relatively quick and inexpensive technique for producing copies of images, the technique is often employed to produce documents that were traditionally formed using other forms of printing or imaging—e.g., impact printing or ink-jet printing. For example, in recent years, toner-based imaging has been employed to produce financial documents, such as personal checks, stocks, and bank notes; legal documents such as wills and deeds; medical documents such as drug prescriptions and doctors' orders; and the like. Unfortunately, because the image is formed on the surface of the substrate, documents produced using toner-based imaging techniques are relatively easy to forge and/or duplicate.
Various techniques for printing or forming secure documents have been developed over the years. Early secure printing techniques generally included improvements to paper onto which material was printed or written. For example, U.S. Pat. No. 1,727,912, issued to Snyder on Sep. 10, 1929 discloses a paper for producing a secure document that includes a coating with relatively low ink absorption properties and a paper body portion that readily absorbs the ink. A secure document is formed by slitting or rupturing the coating during a writing process, such that the ink penetrates the absorbent portion of the paper. U.S. Pat. No. 4,496,961, issued to Devrient on Jan. 29, 1985, discloses another paper-related secure printing technique. Devrient discloses a check paper that includes crushable micro capsules that contain leuco ink and a color acceptor. When an image is written onto a surface of the paper, the micro capsules are crushed and the leuco ink reacts with the color acceptor to produce an image within the body of the check paper, making the image difficult to forge. U.S. Pat. No. 4,936,607, issued to Brunea et al. on Jul. 26, 1990 and U.S. Pat. No. 5,033,773, issued to Brunea et al. on Jul. 21, 1991 both disclose another secure document printing technique that includes microcapsules containing a solvent and a colorant. Upon impact, the microcapsules burst to create a colored halo effect surrounding an image printed onto the surface of the document, making the image printed on the surface of the document more difficult to forge. Although these techniques work relatively well for impact-type printing or copying, the techniques would not work well in connection with toner-based printing methods.
Other techniques for producing secure images include providing special paper coatings to increase smudge resistance of an image created by an electrostatic process. U.S. Pat. No. 4,942,410, issued to Fitch et al. on Jul. 17, 1990 and U.S. Pat. No. 4,958,173, issued to Fitch et al. on Sep. 18, 1990 both disclose a toner-receptive substrate coating that includes polymer binders and mineral fillers above one micron in size. The coating purportedly exhibits high durability smudge resistance compared to otherwise conventional substrates and thus makes forgery by way of removing a portion of the printed image more difficult. However, the coating described in the Fitch et al. patents does not appear to affect an ability to add material to the document or authenticate the originality of the document.
U.S. Pat. No. 5,123,999, issued to Honnorat et al. on Jun. 23, 1992, discloses another type of forgery-resistant paper. The paper of Honnorat et al. includes an aromatic compound and a binder and/or activator. The aromatic compound and binder or activator react with reducing agents typically found in ink eraser felt to produce a coloring effect, indicating attempted erasure of a portion of an image printed on the paper. This technique does not affect an ability to form a copy of the document or to verify an original copy.
U.S. Pat. No. 5,523,167 discloses a technique for producing secure Magnetic Character Recognition (MICR) symbols using a film including an inert backing coated with a mixture of a resin, a filler, a magnetic pigment, a nondrying oil, and an oil soluble dye. Upon impact, a portion of a transfer layer transfers to a document surface to form a magnetically-readable character image. After the transfer, the non-drying oil contained in the transferred coating begins to diffuse into a substrate. The oil carries the visible oil-soluble dye through the substrate, such that the MICR image appears on the opposite side of the substrate.
U.S. Pat. No. 5,124,217, issued to Gruber et al. on Jun. 23, 1992, discloses a secure printing toner for electrophotographic processing. This toner, when exposed to a solvent such as toluene, often used in document forgery, produces a color stain indicative of the attempted forgery. This toner is only useful to disclose an attempted forgery when a particular solvent is used to remove a portion of a printed image. Thus, the toner cannot be used to mitigate copying of the document or forgery by adding material to the document.
Finally, U.S. Pat. No. 5,714,291, issued to Marinello et al. on Feb. 3, 1998, discloses a toner that includes submicron ultraviolet sensitive particles. An authenticity of the document can be verified using an ultra-violet scanner. Requiring use of an ultra-violet scanner is generally undesirable because it adds cost to a forgery analysis and requires additional equipment.
For the foregoing reasons, improved methods and apparatus for forming secure documents using toner-based processing, which are relatively easy and inexpensive, are desired.
SUMMARY OF THE INVENTION
The present invention provides an improved system for producing secure images using a toner-based imaging process and improved methods of forming and using the system. Besides addressing the various drawbacks of the now-known systems and methods, in general, the invention provides a toner-based printing system that produces images that are difficult to alter and that are easy to visually asses whether the image has been altered.
In accordance with one embodiment of the invention, the secure document printing system includes a substrate and a toner. The toner includes a colorant that forms a printed image on a first surface of a substrate and a dye that migrates through the substrate to form a latent version of the image that is visible on a second surface of the substrate. In accordance with one aspect of this embodiment, the toner includes a thermoplastic resin binder, a charge-controlling agent, a release agent, as well as the colorant and the dye. In accordance with a further aspect of this embodiment, the paper includes a migration-enhancing agent formed on or within a substrate such as paper. Exemplary migration-enhancing agents include oils, plasticizers, and other polymeric materials. In general, the migration-enhancing agent facilitates migration of the dye from the first surface of the substrate to the second surface of the substrate and acts as solvent for the dye. The combination of the toner and the substrate can be used to produce a secure image that is difficult to forge and that is easy to determine whether the image is an original copy of the document by comparing the printed image formed on the first surface of the substrate with the dye-formed copy of the image visible from the second surface of the substrate.
In accordance with another embodiment of the invention, a secure toner-based printing system includes a substrate and a toner that includes a colorant that forms a printed image on a first surface of a substrate and a dye that migrates through a portion of the substrate and forms a copy of the image that is visible from the first surface of the substrate. The printed image can be compared to the copy formed with the dye to determine if the original printed image has been altered.
In accordance with a further embodiment of the invention, the toner and/or the substrate include a colorless, dye-forming agent and a co-reactant that reacts with the dye-forming agent to produce a latent image of a printed image.
In accordance with another embodiment of the invention, a substrate including a migration-enhancing agent is formed by admixing the migration-enhancing agent to a paper-pulp mixture. In accordance with one aspect of this embodiment, the migration-enhancing agent includes an oil, a plasticizer, a liquid polymer, or any combination thereof.
In accordance with a further embodiment of the invention, a substrate including a migration-enhancing agent is formed by coating a base with a migration-enhancing agent substance. In accordance with one aspect of this embodiment, the migration-enhancing agent includes an oil, a plasticizer, a liquid polymer, or any combination thereof. In accordance with a further aspect of this embodiment, both a first surface and a second surface of a base are coated with the migration-enhancing agent substance.
In accordance with another embodiment of the invention, a substrate including a colorless, dye-forming agent and/or a co-reactant is formed by coating a portion of the substrate with the dye-forming agent and/or a co-reactant.
In accordance with another embodiment of the invention, a substrate including a colorless, dye-forming agent and/or a co-reactant is formed by adding the dye-forming agent and/or a co-reactant to a pulp-mixture. In accordance with one aspect of this embodiment of the invention, one or both of the dye-forming agent and/or a co-reactant are encapsulated and comprise about 1–5 weight percent of the substrate material.
In accordance with yet another embodiment of the invention, a method of forming a toner includes melt-blending binder resin particles, mixing colorant particles, charge-control agents, release agents, the dye, and migration agents with the resin particles, cooling the mixture, classifying the mixture, and dry blending the classified mixture with inorganic materials. In accordance with alternative embodiments of the invention, the toner is formed using melt dispersion, dispersion polymerization, suspension polymerization, or spray drying.
In accordance with another embodiment of the invention, an image is formed on a substrate by electrostatically transferring an image to a first surface of the substrate and forming a copy of the image that is visible from a second surface of the substrate by applying a toner, including a migrating dye, to the substrate. In accordance with one aspect of this embodiment, the method of forming an image includes providing a substrate that includes a migration-enhancing agent.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
A more complete understanding of the present invention may be derived by referring to the detailed description and claims, considered in connection with the figures, wherein like reference numbers refer to similar elements throughout the figures, and:
FIG. 1 illustrates a system for printing secure documents in accordance with the present invention;
FIG. 2( a ) and FIG. 2( b ) illustrate a check formed using the system of the present invention;
FIG. 3 illustrates a substrate in accordance with one embodiment of the invention;
FIG. 4 illustrates a substrate in accordance with another embodiment of the invention; and
FIG. 5 illustrates yet another substrate in accordance with the present invention.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
DETAILED DESCRIPTION
The following description is provided to enable a person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventors of carrying out their invention. Various modifications to the description, however, will remain readily apparent to those skilled in the art, since the general principles of forming a toner-based system for forming secure images on a document and methods of forming and using the system have been defined herein.
FIG. 1 illustrates a system 100 for printing secure documents in accordance with one embodiment of the present invention. System 100 includes a toner 102 and a substrate 104 , which work together to produce a printed image on a first surface 106 of substrate 104 and a latent copy of the image, underlying the printed image, which is visible from the first ( 106 ) and/or second surface ( 108 ) of the substrate. Documents formed using system 100 are difficult to forge and copies of documents are easily detected, because any mismatch between the printed image and the latent image indicates forgery and a missing latent image is indicative of a copy of the document.
An image is printed onto a substrate using system 100 by transferring toner 102 onto substrate 104 using, for example, an electrostatic or electrophotographic process. In this case, the toner is transferred to a portion of the substrate to create a desired image and the image is fused to the substrate using, for example, heat and/or, and/or pressure, and/or vapor solvent processing. A latent image of the printed image is formed as a result capillary or chromatographic migration of the dye to an area underlying the printed surface of the document.
FIG. 2 illustrates a check 200 formed using system 100 . In particular, FIG. 2( a ) illustrates an image 202 printed on a first surface 204 of the check and an image 206 , which forms as a result of the migrating dye, formed on or visible from an opposite surface 208 of the check.
Referring again to FIG. 1 , in accordance with one embodiment of the invention, toner 102 includes a thermoplastic binder resin, a colorant, a charge-controlling agent, and a migrating dye 110 . Each of the thermoplastic binder resin, the colorant, and the charge-controlling agent may be the same as those used in typical toners. Toner 102 may also include additional ingredients such as a migrating agent 112 . Migrating agent 112 may be configured to assist dye 110 to migrate through the substrate and/or help fuse the dye in place after an initial migration of the dye—to, e.g., mitigate lateral spread of the dye. For illustration purposes, only the dye and the migrating agent are separately illustrated in FIG. 1 . Although the illustrated toner is a one-component toner, multiple-component toner compositions (e.g., toner and developer) may also be used to form secure documents as described herein. Toners suitable for use with this invention are described in application Ser. No. ______ , filed contemporaneously herewith, by the assignee hereof, the contents of which are hereby incorporated herein by reference.
The thermoplastic binder resin helps fuse the toner to the substrate. In accordance with one embodiment of the invention, the binder resin has a melt index of between about 1 g/10 min. and 50 g/10 min. at 125° C. and has a glass transition temperature between about 50° C. and about 65° C. Exemplary materials suitable for the thermoplastic binder resin include polyester resins, styrene copolymers and/or homopolymers—e.g., styrene acrylates, methacrylates, styrene-butadiene—epoxy resins, latex-based resins, and the like. By way of particular example, the thermoplastic binder resin is a styrene butadiene copolymer sold by Eliokem as Pliolite S5A resin.
The colorant for use with toner 102 can be any colorant used for electrophotographic image processing, such as iron oxide, other magnetite materials, carbon black, manganese dioxide, copper oxide, and aniline black. In accordance with one particular example, the colorant is iron oxide sold by Rockwood Pigments as Mapico Black.
The charge-control agent helps maintain a desired charge within the toner to facilitate transfer of the image from, for example, an electrostatic drum, to the substrate. In accordance with one embodiment of the invention, the charge control agent includes negatively-charged control compounds that are metal-loaded or metal free complex salts, such as copper phthalocyanine pigments, aluminum complex salts, quaternary fluoro-ammonium salts, chromium complex salt type axo dyes, chromic complex salt, and calix arene compounds.
As noted above, the toner may also include a releasing agent such as a wax. The releasing agent may include low molecular weight polyolefins or derivatives thereof, such as polypropylene wax or polyethylene wax.
Preferred dyes in accordance with the present invention exhibit a strong color absorbance through substrate 104 , good solubility in a migration fluid, and good stability. Furthermore, ambient heat, light, and moisture conditions, preferably do not detrimentally affect the development properties of the toner, which is non-toxic. In addition, the dyes are preferably indelible. Exemplary soluble dyes for toner 102 include phenazine, stilbene, nitroso, triarylmethane, diarlymethane, cyanine, perylene, tartrazine, xanthene, azo, diazo, triphenylmethane, fluorane, anthraquinone, pyrazolone quinoline, and phthalocyanine. In accordance with one embodiment of the invention, the dye is red in color and is formed of xanthene, sold by BASF under the trade name Baso Red 546, although other color dyes are also suitable for use with this invention.
In accordance with additional embodiments of the invention, the latent image is formed using a color-forming dye such as triphenylmethane or fluorane, and a corresponding co-reactant is contained in either the toner or the substrate. The co-reactant, such as an acidic or electron-accepting compound, reacts with the color-forming dye to produce a latent image of the printed image. Exemplary co-reactant materials include bisphenol A or p-hydroxybenzoic acid butyl ester, which can also function as charge-controlling agents. The color-forming dyes are typically positively charged and thus are used in positively-charged toners. In accordance with alternative embodiments of the invention, described in more detail below, either the color-forming dye and/or the co-reactant may be on or within the substrate and configured to react with each other, e.g., during a fusing process, to form the security image.
When the toner includes a migration-enhancing agent, the agent may be directly incorporated with the other toner components, or mixed with the dye and then mixed with the other toner components, or adsorbed onto silica or similar compounds and then added to the other toner components, or encapsulated in a material that melts during the fusing process, or encapsulated with the dye.
An exemplary toner is formed by initially melt-blending the binder resin particles. The colorant, charge controlling agent(s), release agent(s), dye(s), and the optional migration agent(s) are admixed to the binder resin particles by mechanical attrition The mixture is then cooled and then micronized by air attrition. The micronized particles that are between about 0.1 and 15 microns in size are classified to remove fine particles, leaving a finished mixture having particles of a size ranging from about 6 to about 15 microns. The classified toner is then dry blended with finely divided particles of inorganic materials such as silica and titania. The inorganic materials are added to the surface of the toner for the primary purpose of improving the flow of the toner particles, improving blade cleaning of the photoresponsive imaging surface, increasing the toner blocking temperature, and assisting in the charging of the toner particles. Alternatively, the security toner can be made by other types of mixing techniques not described herein in detail. Such alternative methods include melt dispersion, dispersion polymerization, suspension polymerization, and spray drying.
The following non-limiting examples illustrate various combinations of materials and processes useful in forming a toner in accordance with various embodiments of the invention. These examples are merely illustrative, and it is not intended that the invention be limited to these illustrative examples.
TONER EXAMPLE I
The following example illustrates a preparation of an 8-micron security toner for the use in electrophotographic printing. A toner composition containing the specific composition tabulated below is initially thoroughly pre-mixed and then melt mixed in a roll mill. The resulting polymer mix is cooled and then pulverized by a Bantam Pre-grinder (by Hosokawa Micron Powder Systems). The larger ground particles are converted to toner by air attrition and classified to a particle size with a median volume (measured on a Coulter Multisizer) of approximately 8 microns. The surface of the toner is then treated with about 0.5% dimethyldichlorosilane treated silica (commercially available through Nippon Aerosil Co. as Aerosil R976) by dry mixing in a Henschel mixer.
Exemplary
Specific
Com-
Compositions
Composition
ponent
Chemical
Manufacturer
(weight parts)
(weight parts)
Thermo-
Linear
Image
20–50
46
plastic
Polyester
Polymers-
Binder
XPE-1965
Resin
Charge-
Aniline
Orient
0–3
1
Control-
Chemical
ling
Company-
Agent
Bontron NO1
Colorant
Iron Oxide
Mapico Black
10–50
42
Releasing
Poly-
Sanyo
0–15
5
Agent
propylene
Chemical
Industries-
Viscol 330P
Dye
Azo
Keystone
1–20
6
organic
Aniline Corp.
Dye
Keyplast Red
This prepared mono-component toner is loaded into the proper cartridge for the intended printer such as the Hewlett Packard 5Si printer. An image formed using this toner exhibits a density measuring greater than 1.40 with a MacBeth Densitometer, sharp characters, and initially no migration of the red visible dye is noticed with standard Hammermill 20 pound laser copy paper.
TONER EXAMPLE II
The following example illustrates a preparation of a 10-micron security Magnetic Ink Character Recognition (MICR) toner, including the specific weight composition tabulated below, for use in electrophotographic printing. A toner composition containing the specific composition is initially thoroughly mixed and then melt mixed in a roll mill. The resulting polymer mix is cooled and then pulverized by a Bantam pre-grinder. The larger ground particles are converted to toner by air attrition and classified to a particle size with a median volume (measured on a Coulter Multisizer) of approximately 10-microns. The surface of the toner is then treated with about 1.0% Hexamethyldisilazane treated silica (commercially available through Nippon Aerosil Co. as Aerosil R8200) by dry mixing in a Henschel mixer.
Exemplary
Specific
Com-
Composition
Composition
ponent
Chemical
Manufacturer
(weight parts)
(weight parts)
Thermo-
Linear
Image
20–50
46
plastic
Polyester
Polymers
Binder
XPE-1965
Resin
Charge-
Aniline
Orient
0–3
1
Control-
Chemical
ling Agent
Company
Bontron NO1
Colorant
Iron Oxide
ISK
1–30
10
Magnetics -
MO4232
Colorant
Iron Oxide
Rockwood
10–50
32
Pigments
Mapico Black
Releasing
Poly-
Sanyo
0–15
5
Agent
propylene
Chemical
Industries-
Viscol 330P
Dye
Azo
Keystone
1–20
6
organic
Aniline Corp.
Dye
Keyplast Red
This prepared mono-component toner is loaded into the proper cartridge for the intended printer such as the Hewlett Packard 5Si printer. The resulting image contains a density measuring over 1.40 on the MacBeth Densitometer, high resolution, no noticeable background, and, after initial printing, no migration of the visible red dye with standard Hammermill 20 pound laser copy paper.
For MICR evaluation, the magnetically encoded documents use a E13-B font, which is the standard font as defined by the American National Standards Institute (ANSI) for check encoding. The magnetic signals from a printed document, using the toner described above, were tested using a RDM Golden Qualifier MICR reader. The ANSI standard for MICR documents using the E13-B font requires between 50 and 200 percent nominal magnetic strength. The MICR toner, formed using the formulation provided above, exhibits a MICR signal that has a value of about 100 percent nominal magnetic strength when printing fully encoded documents.
TONER EXAMPLE III
A toner including a co-reactant for use with a substrate including a dye is formed as follows. A negatively charged charge-control agent including a zinc complex of salicylic acid and about 1% of Magee MSO oil are combined. The zinc complex functions as a suitable co-reactant for Copikem Red dye.
FIGS. 3–5 illustrate various substrates suitable for printing secure documents in connection with the toner of the invention. More particularly, FIG. 3 illustrates a substrate 300 , including a base 302 and a coating 304 that includes a migration agent; FIG. 4 illustrates a substrate 400 , including a base 402 and coatings 404 and 406 , which include a migration agent; and FIG. 5 illustrates a substrate 500 , which includes a migration agent 504 embedded or mixed in a base 502 .
Materials suitable for bases 302 , 402 , and 502 include paper such as pulp-based paper products. When the substrate is formed of pulp-based paper, the paper pulp fibers may be produced in mechanical, chemical-mechanical, or a chemical manner. Pulp can be manufactured from, for example, a lignocellulosic material, such as softwood or hardwood, or can be a mixture of different pulp fibers, and the pulp may be unbleached, semi-bleached, or fully bleached. In addition to the pulp fibers, a paper base may contain one or more components typically used in paper manufacturing, such as starch compounds, hydrophobizing agents, retention agents, shading pigments, fillers, and triacetin.
The migration fluid can be any chemical or compound that acts as a solvent for the dye (e.g., dye 110 ) and that can be contained within or on the base without significantly detrimentally affecting the characteristics of the base. Exemplary migration agents suitable for coating 304 , 404 , 406 and for migration agent 504 include oils, plasticizers, liquid polymers, or any combination of these components. In accordance with specific embodiments of the invention, the migration agent includes one or more of: plasticizers such as 2,2,4 trimethyl-1,3 pentanediol diisobutyrate, triacetin, bis (2-ethylhexyl adipate), ditridecyl adipate, adipate ester, or phthalate ester; aromatic and aliphatic hydrocarbons such as: carboxylic acids, long chain alcohols, or the esters of carboxylic acids and long chain alcohols; and liquid polymers such as: emulsion of polyvinyl alcohols, polyesters, polyethylenes, polypropylenes, polyacrylamides, and starches.
When the migration fluid is coated onto the substrate, as illustrated in FIGS. 3 and 4 , any known coating technique such as rod, gravure, reverse roll, immersion, curtain, slot die, gap, air knife, rotary, spray coating, or the like may be used to form a coating (e.g., coating 304 ) overlying a base (e.g., base 302 ). The specific coating technique may be selected as desired and preferably provides a migration-enhancing-agent coating that is substantially uniformly distributed across a substrate such as a traveling web of paper.
A desired amount of the coating containing the migration fluid may vary from application to application. In accordance with one exemplary embodiment of the invention, a substrate includes one coating applied to a surface and the amount of coating is about 0.1 g/m 2 to about 20 g/m 2 , and preferably about 6 g/m 2 to about 8 g/m 2 . In accordance with an alternate embodiment of the invention, illustrated in FIG. 4 , where the substrate includes two coatings, it may be desirable to have different migration-enhancing coatings on each surface of the substrate. For example, in accordance with one specific embodiment of the invention, the coating on the back surface is about 0.1 g/m 2 to about 20 g/m 2 , and preferably about 4 g/m 2 to about 5 g/m 2 , and the coating of the front of the substrate is about 0.1 g/m 2 to about 5 g/m 2 , and preferably about 2 g/m 2 to about 3 g/m 2 . A desired amount or thickness of the coating is determined by factors such as the base paper thickness, porosity of the paper, any paper pre-treatment, and a desired intensity and clarity of an image formed with the die on the back surface of the substrate. For example, if more dye migration is desired, an amount of coating and/or migration-enhancing agent can be increased, and if less dye migration is desired, an amount of coating and/or migration-enhancing agent can be decreased.
The coating that is applied to paper substrate may contain only the migration-enhancing agent. Alternatively, additional chemicals can be added to the coating to, for example, seal the migration fluid, facilitate separation of multiple substrates from one another, and the like. The additional coating components may be applied with the migration-enhancing agent or in a separate deposition step (before or after application of the migration-enhancing agent to the base). For example, the migration fluid can be sealed within the base paper with a wax material such as Kemamide E wax. Alternatively, the coating may include a polymer such as polyvinyl alcohol or polyethylene glycol, to provide a barrier from one sheet of paper to the next. The migration fluid, whether coated onto the substrate or embedded within the base, can also be encapsulated within a suitable polymer shell that ruptures during the printer fusing process. Alternatively, the migration-enhancing agent may be absorbed onto a carrier such as silica and coated onto the paper. In accordance with one particular example of the invention, which is illustrated in FIG. 4 , a first coating 404 , which is on a back surface of the substrate includes a wax and suitable solvents to assist with the application of the coating material (which may evaporate after the coating is applied to the base) and the second coating includes only the migration-enhancing agent and any solvents.
In addition to or as an alternative to the migration-enhancing agent, the coating or active agent may include a co-reactant, a colorless and/or dye-forming material as described above to form a security image of the printed image.
The following non-limiting examples illustrate various combinations of materials and processes useful in forming a substrate in accordance with various embodiments of the invention. These examples are merely illustrative, and it is not intended that the invention be limited to these illustrative examples.
SUBSTRATE EXAMPLE I
The following paper coating, including the specific weight parts of the components tabulated below, is dispersed in a reaction vessel with a high-speed mixer at about 80° C. for about 2 hours. The reaction vessel is allowed to cool to room temperature. The resulting reaction mixture is then filtered using a 50-micron filter. The coating mixture is transferred to a traveling paper web by the gravure roll coating technique. The coating is applied to a substrate in an amount of about 10 g/m 2 coat weight.
Exemplary
Specific
Com-
Man-
Composition
Composition
ponent
Chemical
ufacturer
(weight parts)
(weight parts)
Polyethylene
Dow
8–30
15
Glycol
Chemical
Polyaziridine
Neoresins
0–5
5
Resin
Inc Neocryl
CX100
Bis (2-
Aldrich
3–25
15
ethylhexyl
Chemicals
adipate)
Surfactant
Chemcentral
0–2
1
Triton X100
Solvent
Isopropyl
Interstate
25–50
32
Alcohol
Chemical
Solvent
Distilled
25–50
32
Water
The coated sheets of paper were tested in combination with the security toner on a Hewlett Packard 5SI laser printer. Initially, the resulting image contained acceptable density, acceptable resolution, no noticeable background, and no migration of the visible red dye. Within about 24 hours of printing, a visible indelible image formed on the non-printed side of the paper. The toner on the printed side of the document was later removed and a red indelible image remained.
SUBSTRATE EXAMPLE II
A paper substrate having a weight of about 75 g/m 2 , including a migration-enhancing agent embedded within the substrate, is manufactured using a paper mill. The pulp furnish includes about 60% birch sulphate pulp fibers having a brightness of about 89% ISO and about 40% pine sulphate fibers having a brightness of about 90% ISO. Starch, a hydrophobizing agent, a retention agent, a shading pigment, chalk, and triacetin are added as paper to the pulp mixture. The finished paper is initially formed into rolls of paper and then sheeted to a standard size of 8½ inches×11 inches.
A document was printed using the sheets of paper in combination with the security toner described above using a Hewlett Packard 5SI laser printer. Initially, the resulting image had high density, high resolution, with no noticeable background, and no migration of the visible red dye was apparent. Within 24 hours of printing, an indelible image became visible on the non-printed side of the paper. The toner on the printed side of the document was removed and a red residual image remained.
SUBSTRATE EXAMPLE III
A coating suspension is prepared by mixing 2 grams of amorphous silica, 10 ml of Magiesol MSO oil, and 10 grams of Kenamid E Wax. This mixture is heated to melt the wax and is coated on a back surface of Hammermill Copy Paper using a straight piece of glass. The paper was printed using a toner including Pylam Red dye, manufactured by Pylam Products Co., and security images of the printed image appeared within 24 hours of printing.
SUBSTRATE EXAMPLE IV
A substrate including a colorless dye for use with a toner including a co-reactant is formed as follows. Copikem Red dye is dissolved in Magee MSO oil and coated onto Hammermill Copy Paper.
SUBSTRATE EXAMPLE V
A substrate including a colorless dye for use with a toner including a co-reactant is formed by dissolving about 0.2 grams of Copikem Red dye in about 5 ml of Uniplex 125 A plasticizer, manufactured by Unitex Chemical Co. and coating the mixture onto Hammermill Copy paper.
SUBSTRATE EXAMPLE VI
A substrate including both a dye-forming compound and a co-reactant is formed by separately encapsulating Copikem Red dye and salicylic acid and coating both of the encapsulated components onto Hammermill Copy Paper. When the paper is printed using a printer such as an HP4050 printer, a red security image of the printed images appears on the back side of the paper.
Although the present invention is set forth herein in the context of the appended drawing figures, it should be appreciated that the invention is not limited to the specific form shown. For example, while the invention is conveniently described in connection with pulp-based paper, the invention is not so limited; the substrates in accordance with the present invention may include other forms of paper or other non-paper based substrates Various other modifications, variations, and enhancements in the design and arrangement of the method and system set forth herein, may be made without departing from the spirit and scope of the present invention as set forth in the appended claims.
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A system and method for printing documents that are difficult to forge and that are easy to visually verify are disclosed. The system includes a colorant for printing an image on a surface of a document and a dye for forming a latent version of the image underneath the surface and a substrate that includes a migration agent for facilitating the migration of the dye through at least a portion of the substrate. The migration-enhancing agent may be coated onto a portion of the substrate or embedded within the substrate.
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FIELD OF THE INVENTION
[0001] The present invention is an air intake system for use within residential buildings in conjunction with the existing air duct system.
BACKGROUND OF THE INVENTION
[0002] Today residential homes are equipped with heating, ventilation and air conditioning units (HVAC units) that condition the air within the home tailored to the user's needs. Air is drawn from within the house into the HVAC unit where it is then heated or cooled and through the air ducts delivered back to the house. Using and re-using the air within the home becomes a problem when entities such as pollen, mold spores and other seasonal allergens are introduced into the air. Re-using the air only re-circulates these entities.
[0003] Moreover, homes that have recently been constructed typically have a “new home smell” which is essentially chemical pollutants in the air. There is a need to remove the chemical pollutants.
[0004] Additionally pressurizing a building even slightly inhibits air infiltration of pollutants such as pollen, mold spores, and seasonal allergens from entering penetrations areas, i.e. poor door and window seals, chimney, bathroom, dryer and stove exhaust ducts. Very similar to vacuum packaging, pressurizing a building creates suction or a seal. This suction can be noticed when in a pressurized house by opening a door; the door will pull itself shut. Or opening a window will create a whistling sound. This is caused by the difference in pressure between the inside of the building and the outside, when a window or door is opened, the higher pressure will escape to the lower pressure area much like when the air is let out of a balloon.
[0005] There is a need for a system that avoids re-circulating air within a home. Further, there is a need for a system that prevents air infiltration of pollutants.
[0006] U.S. Pat. No. 6,484,712 B1 issued to Lyons et al. on Nov. 26, 2002 shows a vent cover assembly. Unlike the present invention Lyons' invention is merely a means for ventilation and is not intended for use with a building's HVAC unit.
[0007] U.S. Pat. No. 6,312,327 B1 issued to Hachman et al. on Nov. 6, 2001 shows a vandal resistant fresh air filter housing. Unlike the present invention Hachman's invention is for use with a motor vehicle and is directed towards providing fresh air with out compromising the security of the vehicle.
[0008] U.S. Pat. No. 3,901,135 issued to Nilsson et al. on Aug. 26, 1975 shows a device for distributing ventilating air. Unlike the present invention Nilsson's invention is not intended for use with a buildings' HVAC unit.
[0009] U.S. Pat. No. 3,722,539 issued to Wilmes on Apr. 17, 1973 shows a fresh air vent. Unlike the present invention Wilmes' invention is merely a ventilation device and is not intended for use with a buildings' HVAC unit.
[0010] Thus, a need has been established for a device that can introduce fresh air into the home to be circulated. Additionally there is a need for a device that will pressurize a building to inhibit air pollutants such as pollen and other allergens from entering the building, thus keeping the air within the building cleaner.
SUMMARY OF THE INVENTION
[0011] The present invention is intended for use in residential buildings to draw in outside air and have it mix with the air inside the building to improve indoor air-quality through dilution and building pressurization. Pressurizing a building even slightly inhibits air infiltration of pollutants such as pollen, mold spores, and seasonal allergens from entering penetrations ie, poor door and window seals, chimney, bathroom, dryer and stove exhaust ducts from entering the building.
[0012] By adding a six-inch duct from the inlet side of the central air duct to the fresh air intake, filtered outside air can be introduced while air pressurizing and ventilating the building.
[0013] The present invention can introduce up to 100 CFM of outside air providing for 72,000 to 144,000 cubic feet of air into the home or indoor environment per day. This approach allows for pressurization of the home or indoor environment which eliminates the entry of fine particles, gasses and odors whenever the buildings' HVAC unit fan is running.
[0014] The introduction of 50 CFM of outside air (3000 ft. 3 per hour) has no negative effect on the performance of the HVAC system as it represents approximately 3 to 5% of total air volume going through the HVAC unit. To increase the air ventilation and pressurization, a larger connecting air duct or an induct booster fan can be installed.
[0015] The present invention can be adjusted to provide desired air changes to dilute pollutants and boaters and maintain high oxygen content in the air. The amount of fresh air ventilation can be regulated by dampers located on the fresh air intake system.
[0016] The present invention connects an external filter return grill to the return side of the central air heating and cooling system by an air duct and specialized housing/connectors. When the central air is on it will draw-in filtered outside air, which improves air quality through filtration, serialization, dilution, and pressurization.
[0017] The present invention is configured to enhance its efficiency and sterilization properties. A pre-filter which is made of polyester and carbon is used to arrest a 85% of the particles ≧5 micron and absorb gasses, such as ozone and auto exhaust, and chemicals from landscape fertilizers and pesticides. The second filter is a reusable electrostatic filter. It has anti-microbial properties combined with low airflow resistance and high particle capture ability. An optional third filter, which is a high efficiency filter or High Efficiency Particulate Arrestance (HEPA) and traps 99.97% of particles at 0.3 microns or larger is available.
[0018] Next the volume of the air is regulated by a manual or mechanized damper. Simply closing an opening the damper will control the amount of fresh air being introduced. The damper is followed by a one-way valve that prevents house air from going outside when the fan is not operational.
[0019] After the one-way valve there is a germicidal ultraviolet lamp. The lamps stay cleaner longer due to the air filters, this helps maintain the lamps' intensity. The 6″ round galvanized duct which houses the lamps also assist in the lamps intensity by the reflectance properties of the galvanized sheet metal duct. Also the lamps are placed parallel to the air flow which increases dwell or exposure time to the ultraviolet light increasing its effectiveness and longevity.
[0020] When the central air is in operation it will draw/suck in outside air through the present invention. Once the filtered outside air enters the return box it mixes with the return air from the house. The mixed air (house and filter outside air) is then heated or cooled and dehumidified as usual prior to distribution through the existing air ducts.
[0021] The present invention has one exterior filter return grill that is installed through the buildings wall or foundation. The size of the present invention is tailored to fit into standard preexisting foundation vents.
[0022] These together with other objects of the invention, along with the various features of novelty, which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
[0024] FIG. 1 is an environmental view of the filter components of the present invention.
[0025] FIG. 2 is an environmental view of the duct components of the present invention.
[0026] FIG. 3 is an environmental view of the present invention in communication with a building and its HVAC unit.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] FIG. 1 shows the filter components of the present invention in order of assembly. Exterior aluminum grill ( 10 ) is the outer most component. The fresh air flow is directed into the exterior aluminum grill ( 10 ) between the numerous vented slats ( 15 ) horizontally placed in the exterior aluminum grill ( 10 ). Just behind the exterior aluminum grill ( 10 ) is the carbon pre filter ( 20 ) which is made of polyester and carbon is used to arrest a 85% of the particles ≧5 micron and absorb gasses, such as ozone and auto exhaust, and chemicals from landscape fertilizers and pesticides. Next is the electrostatic filter cloth ( 30 ). The electrostatic filter cloth ( 30 ) is reusable and has anti-microbial properties combined with low airflow resistance and high particle capture ability. A wire mesh ( 40 ) is then place behind the electrostatic filter cloth ( 30 ) to secure the carbon pre filter ( 20 ) and the electrostatic filter cloth ( 30 ) in place. A metal aluminum frame ( 50 ) secures the metal mesh ( 40 ) in place. A HEPA filter ( 60 ) is located just beyond the metal aluminum frame ( 50 ). The High Efficiency Particulate Arrestance (HEPA) filter ( 60 ) is an optional filter and can only improve the thoroughness of the filtration process. Located just past the metal aluminum frame ( 50 ) the HEPA filter ( 60 ) blocks 99.97% of particles 0.3 and larger. All of the aforementioned components are all housed in the square to round adaptor ( 70 ) and the exterior aluminum grill ( 10 ) is secured to it via conventional screws (not shown). Optionally, the square to round adapter ( 70 ) has a gasket adhered to its inner side walls to create an air tight seal between the HEPA filter ( 60 ) and the square to round adapter ( 70 ), thereby controlling filter air bypass. A round collar ( 80 ) is then fitted to the back side of the square to round adaptor ( 70 ). To control the amount of air flow that will enter the building a damper ( 90 ) is attached to the end of the collar ( 80 ). The damper ( 90 ) may be manually adjusted or a mechanized damper ( 90 ) may be installed for easier control.
[0028] To prevent the inside air from going out, a backflow valve ( 100 ) is installed as shown in FIG. 2 . The backflow valve ( 100 ) is then connected to a galvanized hard duct ( 110 ) that will direct the air flow to the buildings' HVAC unit. Within the galvanized hard duct ( 110 ) is the germicidal ultraviolet lamp ( 120 ) that will essentially sterilize the air that passes by. The germicidal ultraviolet lamp ( 120 ) is positioned parallel to the direction of the air flow to increase the time of exposure. Once the galvanized hard duct ( 110 ) reaches the HVAC unit's return box ( 140 ) and second collar ( 130 ) is attached to allow the galvanized hard duct ( 110 ) to attach to the return box ( 140 ). The FAIS housing is then covered with an insulation jacket ( 150 ) as well as other associated hard duct. Once the air has reached the return box ( 140 ), the air is then heated or cooled buy the HVAC unit and is the distributed throughout the building.
[0029] FIG. 3 shows the full diagram of the present invention ( 150 ) while attached to the buildings' HVAC unit ( 160 ) and the duct system ( 170 ) that will distribute the air throughout the building ( 180 ).
[0030] It is important to recognize that the present invention works if the proper relationship between pressure inside the home and outside the home is maintained. Ideally, the difference in pressure between the outside and inside of the home should be 1-10 Pascals. If the difference in pressure is greater than 10 Pascals, then either the outside air will enter the home too quickly or the outside air will not enter the home fast enough. Adverse effects from being greater than 10 Pascals would be not enough air pulled by the present invention into the home, or too much air being pulled from the outside into the home. If not enough air enters the home, the present invention will not achieve its goal of pressurization and desired airflow; however, the other features of the present invention will be unaffected. If too much air enters the home, then the temperature and humidity level of the air entering the home will shift the temperature and humidity in the home.
[0031] A conventional detection means for determining when more than a 10 Pascal difference in pressure between the inside and the outside of the home is contemplated as part of the present invention. When more than a 10 Pascal difference is reached, any conventional means of alerting the user can be employed, from sounding audible or visual alarms, to making alerting telephone calls, to even auto correcting the pressure problem by any conventional mechanical means of increasing or decreasing fan speed or opening or closing the damper ( 90 ) to achieve the 1 to 10 Pascal desired range.
[0032] Manometers are used to detect the pressure changes. and the pressure differential will be displayed. There are many variables which affect the pressure differential in a house: building envelope leakage, temperature, wind. Providing and maintaining more incoming air than exhaust air will maintain the pressure differentials. At this stage of the development the FAIS is used to counter-act the exhausting air and provide the home with an inexpensive means for drawing fresh, filtered, conditioned air into the home. If the manometer were installed, and the home were tight enough, this unit could be a possible means for delivering the necessary amount of air to pressurize the house.
[0033] It is also desirable to ensure that unconditioned air flow into the home remains approximately 10 percent or less of the air handler's air moving capacity. This is because too much unconditioned air entering the home will incur the disadvantages aforementioned; that is, too much unconditioned air entering the home. For example, for with an air handling unit with 1000 cubic feet per minute air handling capacity, you would not want to exceed 100 cubic feet per minute of unconditioned air.
[0034] With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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For use in residential buildings, a device to draw in outside air and have it mix with the air inside the building to improve indoor air-quality through dilution and building pressurization. Pressurizing a building even slightly inhibits air infiltration of pollutants such as pollen, mold spores, and seasonal allergens from entering penetrations ie, poor door and window seals, chimney, bathroom, dryer and stove exhaust ducts from entering the building.
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CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This patent application claims priority to U.S. Provisional Patent Application No. 60/777,256, entitled, “Spectrally matched devices and coatings,” and filed on Feb. 27, 2006. The entire disclosure of the above-noted patent application is incorporated by reference in its entirety herein.
FIELD OF INVENTION
[0002] This invention relates to decoys and other replicates of animals, as used for hunting, for attraction of animals, or for other purposes. In particular, this invention involves a decoy having a surface reflectance that is matched to the light reflection of the animal is it intended to mimic, including ultraviolet wavelengths.
BACKGROUND OF THE INVENTION
[0003] Decoys are commonly used for the hunting of animals such as waterfowl, turkey, dove, deer, and antelope. Decoys exist in numerous forms, including full body decoys and two-dimensional “silhouette” decoys, among others. Regardless of its form, the purpose of a decoy is to mimic a particular species in order to attract animals or for the purpose of deceiving animals to elicit a desired behavior.
[0004] In the production of decoys, much attention is given to making a decoy look as much like the intended animal as possible. The color of a decoy is matched to the color of the animal using techniques common within the industry. Glare from decoys is reduced using various surface treatment methods. Many products are designed so that motion is induced in the decoy. All of these techniques are employed in order to increase the “realism” of the decoy, as it is well understood that increased realism in decoys corresponds to higher performance (i.e., a decoy that better attracts the intended animal).
[0005] It remains a common misconception even today that most animals are color blind. For years it was believed that animals had vision systems that were more primitive than human's three primary color (trichromatic) vision. Modern research is showing that non-human primates are trichromatic and most non-mammal animals, including fish, birds, and shrimp, have vision systems and color perception far beyond humans and primates. It has also been confirmed that many non-primate mammals, while being limited to two primary colors (dichromatic) often are more perceptive of blue colors than humans and even see into ultraviolet (UV) wavelengths. Birds and fish, for instance, are most commonly tetrachromatic; that is, they perceive colors based on a blend of four primary colors. Some animal species even possess five primary colors. These primary colors are determined by the animal's cones, which are special cells in the retina of the eye. Humans possess three types of cones, each having peak sensitivity at specific wavelengths: one at the wavelengths corresponding to blue light, one at the wavelengths corresponding to green light, and one at the wavelengths corresponding to red light—hence our blue, green, and red primary colors. All other colors perceived by humans are the result of these cones being stimulated simultaneously (e.g., simultaneous stimulation of red and green cones causes a human to perceive “yellow”). Birds and fish generally possess four types of cones, although this can vary from one species to another and also through genetic mutations. Other mammals, such as deer, possess only two types of cones, but one of these cones is sensitive to ultraviolet wavelengths.
[0006] This combination of having more cone-types than humans and having the ability to see UV light means that the color perception of many animals is more precise and discriminating than human color perception. That is, animals are capable of seeing color differences that are not apparent to humans.
[0007] Critical to creating realism in decoys is the understanding of vision and color perception in animals. Recent development in the science of color perception in animals has ramifications for decoy manufacturers. The discovery that birds and other game animals can perceive UV light has led some manufacturers in the hunting industry to develop products and modify existing products in an attempt to exploit this discovery. Most manufacturers of hunting products, however, remain unaware of recent scientific developments or are unaware how these developments can be utilized.
[0008] Those manufacturers that have attempted to adapt their products to recent discoveries in animal color perception have not understood the science correctly and have not made the conceptual leap necessary to understand the fundamental differences in color perception between species. The best example, and the most applicable to the present invention, is the development of UV absorbing sprays for use on camouflage and decoys, and the marketing of so-called UV absorbing paints, inks and coatings on decoys. Inventors and manufactures of these products have learned that birds and other game animals can see UV light and have concluded, incorrectly, that UV light is “man-made” and “bad” and must be eliminated from hunting products lest the game animals see the decoys or camouflage for what they are. UV light has been described as having an “eerie glow” that frightens game animals away or a kind of invisible “glare” that must be covered up.
[0009] US patent application 20060117637 by Jeckle describes a coating that absorbs UV light designed to be used for waterfowl decoys, camouflage, and hunting blinds. Also, a product called U-V-Killer™ from Atsko, Inc. is marketed to hunters for the purposes of eliminating all ultraviolet light reflection and blue fluorescence from camouflage clothing and other hunting products.
[0010] While products like these recognize that many animals can see ultraviolet light, they fail to account for the fact that animals themselves as well as other natural objects often reflect UV light. Rather, they teach the opposite, that UV light reflection is unnatural and should be avoided to improve hunting success. Some of these products are intended to be sprayed onto painted decoys, for instance, to make the surface of the painted decoy UV absorbing. Yet it is well known by those skilled in the art of paint formulation that virtually all paint, with the exception of some deep colors, uses UV absorbing titanium dioxide as the primary lightening/whitening pigment and as such, is already inherently UV absorbing. Many exterior durable materials also contain UV absorbing light stabilizers to protect the material from UV degradation. These products teach the application of UV absorbing coatings onto surfaces that often are already UV absorbing.
[0011] Some fishing lures have been developed to reflect or emit UV light to be more visible to the fish, especially at deeper depths. These fishing lures, however, do not teach whether UV should be absorbed or reflected, or whether it is “good” or “bad” on hunting products. It is well know that fishing lures can be rendered more effective by making them more visible, more colorful, and even shinier—depending on the fishing circumstances. It is well know that fishing lures can be effective even when they do not resemble any known bait fish. UV reflecting fishing lures do not teach what will make decoys and camouflage more effective. This art does not teach the natural UV reflection level and pattern of bait fish, only that generic UV reflection can make lures more visible to fish. This art also does not teach how to determine the natural UV reflection of bait fish, other game animals, or natural objects.
[0012] While many man-made objects, especially conventional paints, absorb UV light, recent research has shown that many natural objects as well as animals can reflect UV light. This reflection, while not visible to humans, can be seen through the use of ultraviolet photography, in which UV light is converted to colors that can be perceived by humans. UV photography has revealed patterns and coloration in animals, plants, and other natural objects that may be used by animals or insects for the purposes of identification or attraction.
[0013] A study by Eaton and Lanyon (“The ubiquity of avian ultraviolet plumage reflectance” published in the Proceedings of the Royal Society of London—Biological Sciences in 2003), measured the UV reflection of hundreds of bird feather patches of different colors using UV-Visible spectrophotometry. This study showed that some colors such as white typically exhibited some level of UV reflection but the amount of reflection varied significantly between species. This study, the most comprehensive attempt to date to classify the UV reflectance of birds, did not include the grays, tans, and other light earth tones typically found in many game birds, nor did it investigate the overall pattern of UV reflection for any bird. Other studies have shown that some species of birds have black feathers with significant UV reflection while other black feathers have virtually no UV reflection.
[0014] Taken in their entirety, the present knowledge of UV reflectance in bird plumage cannot be used successfully to predict the amount of UV reflection of a bird based on the human-visible color of the feathers. Feathers that appear white to humans can possess UV reflection from low to moderate to high depending on the species of bird and the location of the feather on the bird. Often male/female pairs of bird species that appear to be identical to humans actually have differing UV reflectance characteristics, making the color difference between the sexes very obvious to birds.
[0015] While is has been established that many game animals can see UV light—although many manufacturers are unaware of it, and those that are aware of it have taught away from the present invention—and it has been established that many animals and natural objects possess UV reflection, it has not been taught by any art, nor is it obvious, what the specific UV reflection of any or all surfaces (such as plumage and fur) of game animals is and how this knowledge, were it to be obtained, can be properly exploited to improve the performance of hunting products such as decoys.
[0016] Jeckle acknowledges this lack of knowledge within the art, stating in 20060117637 that “It is impractical, if not impossible to precisely duplicate the natural reflectance of UV light off the feathers of birds because the reflectance and color hues are in the UV range that humans cannot perceive. Without being able to perceive the reflectance, any attempt of realistically mimicking the reflection is guesswork.” Jeckle concludes that “The solution to this problem is to diminish the reflectance of ultraviolet light while maintaining a presumptively natural appearance in the visible spectrum.”
[0017] It is clear that the UV reflectance levels and patterning of game animals and natural objects such as foliage and a means to reproduce that reflectance on decoys and other hunting products is not known. Jeckel and others teach that because of this lack of knowledge, the only option is to eliminate UV reflection.
[0018] Various materials are used to make decoys, including molded plastics, extruded plastics, polymer foams, and woven or non-woven fabrics. To provide human-visible color for the intended species, several methods can be used. One is to use the inherent color of the material, as is sometimes the case with fabrics and foams. Another method is to incorporate color pigments directly into the material using color compounding methods common in the plastics industry. The most common method is to apply a surface coating, typically an ink or paint that is formulated to have the desired human-visible color. Often, a combination of these methods is used.
[0019] A search of the prior art will show patents and other documents that discuss the use of materials that are sensitive to or resistant to UV light, but these prior art references do not teach the measurement and use of the reflection of UV light. Some references refer to “UV resistance”, which involves the use of materials and coatings to prevent damage such as yellowing due to the effects of UV light. UV-resistant materials are typically UV absorbing, or transparent (in the case of some clear materials), and therefore can not be used to mimic the UV reflectance patterns of animals or objects. Other references discuss the use of UV inks on their products. UV inks are special inks that can be cured under the presence of high-intensity UV light, but they are not intended to reflect UV light.
[0020] Regardless of how artificial color is incorporated, it is formulated to match the intended species or natural object based on human color perception, without accounting for the differences between human and animal color vision. Industrially, color matching is typically done using the L-a-b scale, which assigns each color a point in the three dimensional space defined by three axes: L (lightness), a (magenta to green) and b (blue to yellow). This system is based on the peak sensitivity of the cones of the human eye and is therefore an inadequate method for matching colors as perceived by animals.
[0021] Ultraviolet-visible (UV-Vis) reflectance spectrophotometry is an analytical method of measuring the reflection of light from a surface over a range of wavelengths. Instruments used for this measurement shine light at an object and measure the intensity of the reflected light. By changing the wavelength of the incident light, a graph of the intensity of reflected light versus wavelength can be developed. Using this method to assist the matching of colors is not dependant on the color vision of humans and therefore avoids the inadequacies of the L-a-b method for animal color vision.
[0022] While many “man-made” objects are UV-absorbing, some materials, including some fabrics and polymer foams which are naturally white in color, reflect UV light. However, this UV reflection does not match that of any specific animal species and may be either more or less reflective at a particular wavelength. Other materials that appear white to humans are UV fluorescent, which means they absorb UV wavelengths and emit light at human-visible longer wavelengths. This is why some fabrics appear extra-bright under a UV emitting black light. This effect alters the color of the object in a way that can be perceived by some animals.
[0023] U.S. Pat. No. 4,691,464 by Rudolph describes a flexible fabric covering which can be placed over a decoy in an attempt to enhance the life-like accuracy of the decoy. Rudolph describes the use of reflective panels placed in strategic locations on the fabric covering in an attempt to match the iridescence of the brightly colored secondary feathers of a bird. Iridescence is created by manipulating the surface material such that the color of the surface appears to shift depending on the angle by which the surface is observed. Iridescence does not affect the UV characteristics of the decoy, and the use of a reflective panel on a decoy covering does not accurately mimic the reflective characteristics of a decoy as seen by an animal. Rudolph does not teach the use of UV reflective characteristics to mimic those of an animal.
[0024] The UV reflection properties of minerals have been measured and it is known, though not widely, by those skilled in the art, which pigments and fillers may be used to achieve ultraviolet light reflection. Snow is known to have high UV reflection and materials such as Tyvek have been found to have similar UV reflection to snow and have been cited as a material of choice for snow camouflage for military applications. Snow and Tyvek have relatively flat reflectance curves when measured across the UV spectrum of sunlight. Bird feathers have complex reflection curves, or signatures, where each wavelength of UV light (and visible wavelengths) has a different reflectance level. This complexity of reflection curvatures in the UV of animal feathers, fur, and plant foliage is not fully understood, with only a fraction of natural, plant, or animal surfaces having been studied for UV reflection.
[0025] It is also not known which pigments, materials, or combinations of materials are needed to produce the UV reflection signature of game animals. UV reflection is not a singular thing any more than blue or red are singular colors. There are an infinite number of possible reflectance curvatures across the UV wavelengths visible to animals, just as there are an infinite number of possible reflectance curvatures in the human-visible range that we perceive as innumerable shades of blues, red, yellows, etc.
[0026] To achieve maximized color realism, and therefore improved performance, what is needed is a decoy that is designed to match or closely mimic the coloration and patterning in the entire light reflectance spectrum of the vision system of the animal which it is intended to mimic. To develop decoys that match the UV reflection of the animal, plant, or natural surface the product is mimicking requires filling the knowledge gap of the UV reflection signatures of those surfaces. To determine those UV signatures requires refining a method to determine said signatures. When the UV signatures are known, the next step needed is to synthesize existing art in materials sciences (for example, paint color matching in the visible wavelengths) with what is known about the UV reflection of materials. This effort must be combined with the study of the UV reflection of candidate materials whose UV reflection is not known. This gained knowledge and newly developed methods must then be successfully applied to decoy manufacturing methods.
SUMMARY OF INVENTION
[0027] In one aspect of the invention, the outer surface of an animal decoy is modified to match or closely mimic the actual reflectance of the animal in the wavelengths of light which are visible to the animal.
[0028] In another aspect of the invention, portions of the outer surface of an animal decoy are modified to possess bright UV reflectance where white areas exist on the corresponding areas of the animal, and moderate UV reflectance where gray or tan areas exist on the corresponding areas of the animal.
[0029] These aspects and others are achieved by the present invention, which is described in detail in the following specification and accompanying drawings which form a part hereof.
BRIEF DESCRIPTION OF DRAWINGS
[0030] FIG. 1 shows the typical ultraviolet reflectivity patterns of two types of waterfowl.
[0031] FIG. 2 shows the ultraviolet reflectance curves given by the various body parts of typical waterfowl compared against the ultraviolet reflectance curves given by typical decoy coatings and materials found in the prior art.
[0032] FIG. 3 illustrates an ultraviolet imaging system used to determine the patterns and relative intensity of the UV reflecting area of an animal.
[0033] FIG. 4 illustrates a laboratory set up using a UV-Vis spectrophotometer to determine the quantitative reflectance curve across the spectrum of the animal vision system.
[0034] FIG. 5 is a flowchart of the process of creating animal decoys exhibiting realistic UV reflections.
DETAILED DESCRIPTION
[0035] It must be understood that, just as the human-visible colors present on an animal vary greatly over the surface of that animal, the ultraviolet (UV) light reflected from the surface of that animal also varies greatly. A human-visible color such as the green found on the head of a drake Mallard duck is simply a set of reflected wavelengths of light that falls within the spectrum of light visible to humans; specifically, it is wavelengths of light that humans perceive as the color green. Depending on the exact wavelength and intensity of the reflected light, the color “green” may range in appearance from blue-green to yellow-green. Similarly, the amount of UV light, as well as the specific wavelengths of UV light, reflected from the surface of an animal can vary greatly, creating different “colors” of UV light. Although these UV colors are not visible to humans, they are visible to many animals, and should be accounted for when creating realistic models or decoys of those animals. That is the intent of the present invention.
[0036] FIG. 1 illustrates the UV reflectance patterns of two different waterfowl. Although waterfowl are used as examples herein, it should be understood that any type of animal can be used with similar results. FIG. 1 shows areas of high UV reflectance 10 , areas of medium UV reflectance 20 , and areas of little or no UV reflectance 30 in the patterns in which they would typically appear on a drake Mallard duck or a Canada goose. Although the present invention shows areas of high UV reflectance 10 are often seen associated with areas of white or light human-visible colors on the waterfowl, studies have shown that this is often not the case for all white colored animals. Similar studies have shown that areas of black can be associated with significant UV reflectance, and areas of white can have very little UV reflectance.
[0037] FIG. 2 illustrates the UV-Visible reflectance curves of example game animals as compared to materials found in the prior art used for coating decoys. The visual spectrum of humans 60 and the visual spectrum typical of birds and fish 61 are indicated along the bottom access of the line graph. The reflectance curves of several materials taught in the prior art, including white 40 , light tan 41 , and tan 42 , are shown. Each of the materials 40 , 41 , and 42 demonstrates very little reflectance in the wavelengths of ultraviolet light between 300 and 400 nanometers. The reflectance curves of a Snow goose body and wing 50 , a Canada goose cheek patch 52 , and a Canada goose breast 54 are also shown. The reflective characteristics of animal components 50 , 52 , and 54 cannot adequately be implemented using materials 40 , 41 , and 42 . Animals which can see in the visual spectrum of birds and fish 61 will see materials 40 , 41 , and 42 as significantly different colors than animal components 50 , 52 , and 54 , even though materials 40 , 41 , and 42 will appear as close matches in the human visible spectrum 60 .
[0038] The present invention describes a method of mapping the reflectance characteristics of the outer surface of an animal. Refer now to FIG. 3 and FIG. 4 . FIG. 3 illustrates a test set-up which uses UV imaging or similar techniques to determine areas of low, medium, and high reflectance on the outer surface of the animal. The animal subject 70 is placed in front of a UV imaging camera 74 . Light sources 72 emit ultraviolet light onto the animal subject 70 , and the reflected UV light is detected by the UV imaging camera 74 . A monochrome image 78 , showing areas of high UV reflectance as bright areas, moderate UV reflectance as shades of gray and no UV reflectance as dark areas, is displayed on a computer display 76 . The data from the image 78 is interpreted and recorded to show a map like that shown in FIG. 1 .
[0039] FIG. 4 illustrates an additional step in which the animal subject 70 is mapped with a UV-Vis spectrophotometer 80 to determine the quantitative reflectance curves 84 across the spectrum of the animal vision system. Surface measurements are taken from whole or partial samples 82 from carcasses or other natural samples. A reflectance curve 84 is generated in this manner for each different sample 82 . Example reflectance curves 84 can be seen in greater detail for the animal components 50 , 52 , and 54 on FIG. 2 .
[0040] FIG. 5 is a flowchart of the process of creating animal decoys exhibiting realistic UV reflections. In Step 90 , a UV reflectance surface map is created for the animal subject 70 . This is done by the UV imaging process previously described herein in FIG. 3 . In Step 91 , UV reflectance curves 84 are created for various samples 82 of an animal carcass. This is done by the UV-Vis process previously described herein in FIG. 4 . The UV image 78 and reflectance curves 84 are analyzed to create specific formulations of paint or other surface covering material, as shown in Step 92 . In Step 93 , the UV-reflective paint or material is applied to the outer surface of an animal decoy, or the decoy itself is composed of said materials, to create a model of the animal subject 70 that appears visually realistic to the animal in the animal's visual spectrum.
[0041] The methods of modifying the outer surface of an object to change its reflective characteristics, as described in Step 93 on FIG. 5 , are known to someone skilled in the art, but a short description of these methods is provided herein. Two methods exist for changing the color or light-reflecting characteristics of an object, adding pigments to the surface of the object, or changing the structure of the surface such that the light reflected from that surface changes. Specifically, these techniques can be used to add varying levels of UV reflectance to an object.
[0042] The pigments used to achieve UV reflectance can be several organic and inorganic pigments that posses UV reflectance. Specifically, barium sulfate, calcium carbonate, antimony oxide, magnesium oxide, strontium carbonate, barium carbonate, many zirconates and zirconias, many metals and metal oxides, some ceramic powders, and many titanates, among others, are known to reflect UV light.
[0043] The coatings or plastic resins used to carry the UV reflecting pigments can be several types but the preferred materials are UV transparent or otherwise resistant to UV degradation. Specifically, binders utilizing acrylic are preferred. Organic or inorganic binders used in coatings can also be used that are partially or selectively UV or visible light absorbing.
[0044] Another method of creating UV reflection is altering the structure of the surface such that the amount and type of light reflected is changed. Specifically, creating small voids within or microstructures on the surface or coating can scatter UV light because of the refractive index difference between the material and the voids. This can be accomplished by adding fillers at high concentrations, above what is known as the critical pigment volume concentration, by adding particles which themselves have small voids, or by using processes that create voids. This void scattering is also accomplished with certain materials such as some fabrics like Tyvek and some foam plastics.
[0045] Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims. In particular, any animal, plant, seeds, or even an object, can be used as a decoy if it aids in the deception of an animal or human. The animals discussed directly herein are intended as examples only. In addition, methods of measuring the UV reflectance of an animal other than those discussed herein may be used to achieve the same or similar results.
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A decoy with a surface reflection which closely matches the spectral reflectance of the animal or object that it is designed to mimic, including both human-visible and ultraviolet wavelengths, with the intent of making the decoy appear more realistic to animals who can see in both the human-visible and ultraviolet spectrums.
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BACKGROUND OF THE INVENTION
The present invention relates to improvements in apparatus for severing running webs of paper, imitation cork or the like. More particularly, the invention relates to improvements in apparatus which can be utilized, for example, in filter tipping machines to subdivide webs of cigarette paper, imitation cork or other types of tipping paper into discrete uniting bands. Such uniting bands can be utilized in filter tipping machines to connect plain cigarettes of unit length or multiple unit length with filter plugs or filter mouthpieces of unit length or multiple unit length. Still more particularly, the invention relates to improvements in severing or subdividing apparatus of the type wherein the web which is to be subdivided into discrete sections or uniting bands is caused to advance between a rotary counterknife or anvil and a rotary knife carrier which is provided with one or more adjustable knives serving to cut across the running web during travel toward and through the nip of the counterknife and the knife carrier.
As a rule, the rotary knife carrier of a severing apparatus for running webs of tipping paper or the like is provided with several axially parallel grooves for reception of knife holders which, in turn, support the blades whose cutting edges sever the running web while moving past the rotary counterknife. The knives and/or their holders are adjustable individually so as to ensure that the cutting edge of each knife will actually contact the peripheral surface of the rotary counterknife in the course of a cutting or severing operation. Such adjustability of the knives ensures that the cutting edges will form clean cuts all the way across the running web, namely, from the one to the other marginal portion of the web. Reference may be had to the commonly owned U.S. Pat. No. 3,340,757 granted Sept. 12, 1967 to Willy Rudszinat. The patented apparatus utilizes knives which are pitovable on axially movable wedge-like adjusting elements so that any axial displacement of the adjusting elements results in radial displacement of the knives with reference to the axis of the knife carrier. Adjustability of the knives is desirable for several reasons, namely, for the aforediscussed reason that the cutting edges of all knives should actually contact the peripheral surface of the counterknife upon completion of a cut and also because the wear upon the cutting edges is quite pronounced so that it is necessary to intermittently move the knives radially outwardly to compensate for wear upon their cutting edges. As a rule, an adjustment is necessary after a certain period of continuous use, for example, upon completion of each eight-hour shift. Such cutting apparatus operate quite satisfactorily except that the adjustment of each and every knife upon completion of a shift or after elapse of another interval takes up a substantial amount of time. Moreover, it is often necessary to resort to highly accurate and sensitive calibrating or testing apparatus which must ascertain the magnitude of force or pressure with which the cutting edges of the orbiting knives engage the peripheral surface of the counterknife.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the invention is to provide a novel and improved apparatus for subdividing running webs of cigarette paper or the like into individual sections wherein the adjustment of knives after a certain period of use and the resulting wear upon the cutting edges can be completed within surprisingly short intervals of time.
Another object of the invention is to provide a cutting or severing apparatus wherein the knives are adjustable individually the same as in conventional apparatus, but are also adjustable jointly to ensure identical shifting of the cutting edges with reference to the knife carrier.
A further object of the invention is to provide novel and improved adjusting means for the knives in a cutting or severing apparatus of the above outlined character.
An additional object of the invention is to provide a machine, such as a filter tipping machine, which embodies the improved severing apparatus.
A further object of the invention is to provide a severing apparatus which can be utilized as a superior substitute for severing apparatus of the presently known design.
Still another object of the invention is to provide an apparatus which can reliably sever a running web of paper or the like and wherein the cutting implements can be adjusted within a fraction of the time which is required for such adjustment in a conventional severing apparatus.
A further object of the invention is to provide a severing apparatus which is more versatile, but need not be bulkier, than conventional severing apparatus.
The invention is embodied in an apparatus for subdividing a running web, especially a web or strip of tipping paper in a filter tipping machine, into discrete sections. The apparatus comprises a rotary knife carrier, a counterknife (preferably a rotor whose axis is spaced apart from the axis of the knife carrier) which is adjacent to and defines with the carrier a path for the running web substantially at right angles to the axis of the carrier, a plurality of adjustable knives on the carrier, a discrete first adjusting device for each knife (each such adjusting device comprises means for adjusting the respective knife substantially radially of the carrier), and an adjusting device which is common to all of the knives and includes means for simultaneously moving all of the knives substantially radially of the knife carrier.
The knife carrier is preferably provided with substantially radially extending (and preferably axially parallel) guide means in the form of grooves or the like, and each such guide means movably receives one of the knives.
The common adjusting device preferably comprises a support for all of the first adjusting devices, and such support can constitute a component of the means for simultaneously moving all of the knives.
Each of the first adjusting devices can comprise a knife-displacing member having a cam which engages the respective knife, and means for moving the displacing member in parallelism with the axis of the knife carrier to thereby move the respective knife radially of the carrier through the medium of the cam on the displacing member. The aforementioned support of the common adjusting device can carry all of the displacing members as well as the means for moving such displacing members in parallelism with the axis of the knife carrier. The means for moving the displacing members can comprise screws which are rotatably mounted in the support. The aforementioned cams can constitute substantially wedge-like portions of the displacing members, and such wedge-like portions can cooperate with pivots for the respective knives (the pivots enable the knives to tilt in their guide grooves in planes including the axis of the knife carrier).
The support preferably includes an annulus (e.g., a ring-shaped collar or flange) which is adjacent to one end face of the knife carrier. The common adjusting device preferably further comprises means for moving the support and the first adjusting devices axially of the knife carrier. To this end, the carrier can comprise a shaft which is surrounded by the aforementioned annulus and preferably also by a sleeve-like portion of the support. Such sleeve-like portion has an end portion which is remote from the annulus and extends beyond the shaft to carry a lid for an externally threaded rotary member constituting the means for moving the support axially of the knife carrier. The axis of the externally threaded member is parallel to the axis of the shaft, and the shank of this member has a first set of threads meshing with the shaft as well as a second set of threads meshing with the lid. The lead of one set of threads is different from the lead of the other set of threads so that, when the externally threaded member is rotated relative to the shaft, the support moves axially of the shaft and the knife carrier to thereby simultaneously displace all of the first adjusting devices and effect an appropriate adjustment of all of the knives radially of the knife carrier.
The apparatus can comprise one or more locating blocks which hold the carrier and the counterknife against movement relative to each other radially of the carrier.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved severing apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
The single FIGURE of the drawing is a fragmentary axial sectional view of a severing apparatus for running paper webs or the like which is constructed and assembled in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The drawing illustrates a cutting or severing apparatus which comprises a rotary knife carrier 1 having a driven shaft 4 receiving torque from the main prime mover of a filter tipping machine, for example a machine of the type disclosed in commonly owned U.S. Pat. No. 4,193,409 granted Mar. 18, 1980 to Gunter Wahle et al. The disclosure of this patent is incorporated herein by reference.
The severing apparatus further comprises a rotary counterknife 2 which can constitute a suction drum and is rotatable about an axis that is parallel with the axis of the shaft 4. With reference to the aforementioned patent, the counterknife 2 corresponds to the counterknife 19 of the patent, and the knife carrier 1 corresponds to the knife carrier 21 of this reference.
The knife carrier 1 and the counterknife 2 are mounted, at each of their axial ends, in the frame or housing 3 of a filter tipping machine. A portion of such frame is shown in the right-hand part of the drawing. Reference may also be had to German patent application Ser. No. P 32 19 046.8.
The knife carrier 1 is provided with axially parallel radially extending peripheral guide grooves 6 which are equally spaced from one another, as considered in the circumferential direction of the carrier 1. Each of the guide grooves 6 receives one of several adjustable knives 7 of which only one is actually shown in the drawing. The distribution of knives 7 about the shaft 4 may be similar to that shown in FIG. 1 of the aforementioned U.S. Pat. No. 3,340,757 to Rudszinat. Each of the knives 7 comprises a holder 8 and a pivotable cutting or severing blade 9 which is mounted in the respective holder 8 and has an elongated cutting edge 11 serving to sever the web (not shown) which advances between the carrier 1 and the counterknife 2 at right angles to the plane of the drawing. The peripheral surface of the counterknife 2 can be provided with suction ports (not shown) which are connected to a suction generating device so that the counterknife 2 attracts the leader of the web during travel through the nip of the rotary parts 1 and 2. Such mode of transporting the web toward, and of transporting the uniting bands or web sections beyond, the severing station is known in the art of filter tipping and analogous machines.
The holders 8 of the knives 7 are tiltable in the respective grooves 6 of the carrier 1. To this end, the peripheral surface of the carrier 1 is formed with a narrow circumferentially extending recess 12 which receives discrete pivot members 13, one for each knife 7. Each pivot member 13 is a bifurcated component having two prongs 13a which flank and can be rigidly connected to the central portion of the respective knife holder 8. One of the prongs 13a is indicated in the drawing by broken lines. The inner side or surface 14 of the wedge-like central portion of the pivot member 13 slopes with reference to the axis of the shaft 4 and abuts against a complementary cam face 16 provided on an axially movable wedge-like centrally located cam portion of a knife-displacing and adjusting member 18 forming part of an adjusting device 23. The apparatus which is shown in the drawing comprises a discrete adjusting device 23 for each of the knives 7. The displacing member 18 is shiftable in parallelism with the axis of the shaft 4 by a moving means here shown as an adjusting screw 19 which can be locked in a selected position by a lock nut 22 and whose external threads mesh with internal threads provided in a tapped bore which is machined into the right-hand end face of the corresponding displacing member 18. The latter is biased in a direction to the right, as viewed in the drawing, by a coil spring 17 which is inserted into the leftmost portion of the respective passage 1a provided in the knife carrier 1 for the displacing member 18. The adjusting screw 19 is rotatably mounted in an annular collar or flange 21 forming part of a sleeve 32 surrounding and having an end portion extending axially beyond a smaller-diameter extension or stub 4a of the shaft 4. The coil spring 17 ensures that the displacing member 18 moves in a direction to the right when the screw 19 is rotated in one direction, and the spring 17 is caused to store energy when the screw 19 is rotated in the opposite direction so as to move the displacing member 18 to the left, as viewed in the drawing, whereby the cam face 16 causes the corresponding pivot member 13 to move radially outwardly and to shift the corresponding knife 7 nearer to the peripheral surface of the rotary counterknife 2. The pivot member 13 can move radially inwardly, namely, nearer to the axis of the shaft 4, when the displacing member 18 is moved in a direction to the right, as viewed in the drawing, so that the coil spring 17 can dissipate some energy. Pivotability of each knife 7 is desirable because this ensures that the entire cutting edge 11 of each blade 9 can engage the peripheral surface of the counterknife 2 when the severing apparatus is in actual use. The ends of the guide grooves 6 in the knife carrier 1 are closed by ring-shaped covers 24 which are secured to the knife carrier by annuli of screws 26 or analogous fasteners. The collar 21 is adjacent to the right-hand end face of the knife carrier 1.
Each end face of each holder 8 is formed with an axially parallel blind bore 27 for reception of a coil spring 28 and a spherical element 29 a portion of which extends into a shallow recess machined into the internal surface of the respective ring-shaped cover 24. The bottom surfaces 31 of aligned recesses in the internal surfaces of the two ring-shaped covers 24 taper toward each other in a direction radially of and away from the axis of the shaft 4. The spherical elements 29 in the blind bores 27 of each holder 8 bear against the respective inclined bottom surfaces 31 under the action of the associated coil springs 28. The purpose of the spherical elements 29 is to maintain the holders 8 in such angular positions with reference to the corresponding pivot members 13 that the cutting edges 11 of the corresponding blades 9 are exactly parallel with the axis of the counterknife 2 but that the angular positions of the holders 8 can change (by allowing the holders 8 to pivot with reference to the corresponding pivot members 13 against the opposition of the coil springs 28) if the cutting edges 11 are not exactly parallel with the adjacent portions of the peripheral surface of the counterknife 2. In other words, the coil springs 28 and the spherical elements 29 cooperate with the inclined bottom surfaces 31 to permit for angular adjustments of each holder 8 at the onset of a severing operation. However, once the angular positions of the holders 8 are properly selected, so that the corresponding cutting edges 11 are exactly parallel with the axis of the counterknife 2, the coil springs 28 retain such holders in the adjusted positions. The bias of the springs 28 is sufficiently strong to prevent any changes in the inclination of the holders 8 under the action of centrifugal force, i.e., the angular positions of the holders 8 will be changed only if the cutting edges 11 of the respective blades 9 are not exactly parallel with adjacent portions of the peripheral surface of the counterknife 2.
The aforementioned sleeve 32 forms part of a support for the adjusting devices 23, and such support forms part of an additional adjusting device 43 which is common to all of the knives 7. The sleeve 32 is surrounded by a first antifriction ball bearing 33, which is installed in the frame member 3, and by a second antifriction ball bearing 36 which is installed in a block-shaped locating member 34 serving to hold the knife carrier 1 and the counterknife 2 against radial movement relative to one another. Reference may be had to the aforementioned commonly owned German patent application.
The sleeve 32 is shiftable axially of the stub 4a by a an externally threaded rotary member here shown as a screw 41 which has an externally threaded shank including a portion 38 in mesh with a lid 37 forming part of the aforementioned support and secured to the right-hand end portion of the sleeve 32 by one or more screws 32a or analogous fasteners. The lid 37 is adjacent to the right-hand end face of the stub 4a which latter is provided with a centrally located tapped blind bore for the externally threaded end portion 42 of the shank 41 of the shifting screw 41. The screw 41 can be releasably held in a selected angular position by a lock nut 39 which then bears against the right-hand end face of the lid 37. The direction of inclination of the threads on the portions 38 and 42 of the shank of the screw 41 is the same; however, the lead of each of these threads is different. For example, the thread on the portion 38 may be of the type M 10×0.75, and the thread on the end portion 42 may be of the type M 12×1. When such threads are used, one revolution of the shifting screw 41 brings about a relative axial movement between the sleeve 32 and the shaft 4 through a distance of 0.25 mm. The sleeve 32 thereby moves all of the individual knife adjusting devices 23 in parallelism with the axis of the shaft 4 and causes all of the members 18 to displace the associated pivot members 13 through identical distances, namely, radially of the shaft 4. In other words, the common adjusting device 43 can effect simultaneous shifting of the members 18 in parallelism with the axis of the shaft 4, and each adjusting device 23 can effect individual displacements of the respective displacing members 18 in parallelism with the axis of the shaft 4.
An important advantage of the improved severing apparatus is that each of the knives 7 can be adjusted independently of the other knife or knives 7. However, the common adjusting device 43 enables the operator to simultaneously adjust all of the knives 7 through identical increments which normally suffices to ensure accurate positioning of the cutting edges 11 with reference to the counterknife 2 (i.e., to ensure that the cutting edges 11 bear with requisite pressure against the periphery of the member 2 when the adjustment through the medium of the device 43 is completed, for example, after an 8-hour shift). Individual adjustments of the knives 7 are desirable and normally necessary when a fresh knife is inserted into the corresponding groove 6. Simultaneous adjustment of all of the knives 7 is advisable and is sufficiently accurate if it is carried out after a certain period of use of the severing apparatus. In other words, the individual adjusting devices 23 allow for accurate positioning of a freshly inserted or reinserted knife 7 in the corresponding groove 6, whereas the device 43 compensates for uniform or substantially uniform wear upon the cutting edges 11 of all knives 7 after a certain period of use. It has been found that, if the knives 7 are properly positioned in their grooves 6 as a result of accurate adjustment with assistance from the corresponding devices 23, the wear upon the cutting edges 11 is at least substantially uniform while the apparatus is in actual use.
Another important advantage of the improved apparatus is that the adjustments can be carried without necessitating even partial dismantling or removal of the severing apparatus from the machine, such as a filter tipping machine. The dismantling is indispensible in connection with conventional severing apparatus which merely embody adjusting features for individual knives. Accurate adjustment of each knife after a certain period of wear, for example, after each shift, can be achieved only if a conventional severing apparatus is removed from the machine frame and is tested in a suitable instrument, such as shown in FIG. 8 of the aforementioned U.S. Pat. No. 3,340,757 to Rudszinat. The common adjusting device 43 of the improved apparatus obviates the need for removal of the apparatus from the machine frame after completion of each shift or at other intervals. It has also been found that the improved severing apparatus can be used with particular advantage when the distance between the axes of the carrier 1 and counterknife 2 is fixed, i.e., if the apparatus is installed in a machine frame 3 comprising one or more locating blocks of the type shown at 34. The utilization of locating blocks for the carrier 1 and counterknife 2 is especially desirable and advantageous in modern high-speed tobacco processing machines which are designed to turn out many thousands of rod-shaped articles per minute. The main purpose of the locating blocks 34 is to reduce the noise in such rapidly operated machines. The reasons for such reduction in noise are fully disclosed in the commonly owned U.S. patent application Ser. No. 385,257 filed June 4, 1982 by Schlisio et al.
Another important advantage of the improved apparatus is its compactness. This is attributable to the feature that the sleeve-like element 32 of the common adjusting device 43 constitutes a support or retainer for the individual adjusting devices 23. As explained above, the individual adjusting devices 23 are mounted on the flange or collar 21 of the sleeve-like element 32.
The provision of the aforediscussed threads on the portions 38 and 42 of the shank of the shifting screw 41, and the mutual inclination of such threads, ensure a highly accurate adjustment of all knives 7 in response to rotation of the screw 41.
The improved severing apparatus can be utilized in existing filter tipping or analogous machines as a superior substitute for conventional severing apparatus. Furthermore, the improved apparatus can be used with equal or similar advantage in many other types of machines wherein a continuous web (for example, an adhesive-coated web) is to be subdivided into shorter sections or bands of desired length. The tiltability and adjustability of knives 7 renders it possible to prevent excessive wear upon and scoring of the peripheral surface of, the counterknife 2 so that such part can be utilized for long intervals of time.
It will be readily appreciated that numerous modifications may be carried out in the improved apparatus without departing from the spirit of the invention. For example, the individual adjusting devices 23 can be modified in a number of ways, and the same holds true for the common adjusting device 43. All that counts is to ensure that the severing apparatus is provided with individual adjusting devices, one for each of the adjustable knives 7, and that the apparatus is further provided with a common adjusting device which can simultaneously adjust each and every knife so that such operation can be completed within a small fraction of the time which is required in a conventional severing apparatus. Furthermore, the common adjusting device 43 is preferably mounted in such a way that it is readily accessible to an attendant at the outer side of the machine frame so that the attendant can gain access to the shifting screw 41 or to an analogous shifting element preparatory to simultaneous adjustment of all cutting implements.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the appended claims.
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A running web of tipping paper in a filter tipping machine is attracted to the peripheral surface of a rotary suction conveyor constituting a counterknife for a set of equidistant knives which are radially movably mounted in axially parallel grooves of a rotary knife carrier. Each knife is adjustable radially of the carrier by a discrete first adjusting device, and all of the knives are adjustable simultaneously by a common adjusting device having a support movable axially of the carrier and mounting all of the first adjusting devices. Simultaneous radial adjustment of all of the knives by the common adjusting device is effected after certain periods of use and attendant wear upon the cutting edges of the knives.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] This invention relates to valves and, in particular, the field of pneumatic valves.
[0003] 2. Description of Related Art
[0004] It is well known in the field of valves to provide valve control signals for remotely causing valves to open and close, in order to permit fluid flow therethrough. A common method for performing this was to provide a solenoid capable of moving a piston between valve open and valve closed positions. In solenoid controlled valves of this type, a control current was applied to the coil of the solenoid to energize the solenoid and produce electromagnetic flux capable of moving the piston. Many examples of such solenoid actuated valves are known.
[0005] One example of a solenoid actuated valve is taught in U.S. Pat. No. 3,379,214, entitled “Permanent Magnet Valve Assembly,” issued to Weinberg on Apr. 23, 1965. Weinberg teaches a permanent magnetic valve assembly, having an electromagnetically actuated valve member, wherein a coil was energized to provide electromagnetic flux. A permanent magnet was also provided to provide permanent magnetic flux. When the flux of the coil that was energized opposed and exceeded the flux of the permanent magnet, a plunger was shifted. A flux in the opposite direction by an opposing current could move the piston in the opposite direction.
[0006] U.S. Patent Application Publication No. 2001/0050705, entitled “Magnetically-Actuated Fluid Control Valve”, published on Dec. 13, 2001 and based upon U.S. patent application Ser. No. 09/930,098, also included a magnetic actuator containing both a permanent magnet and an electromagnet. An armature, configured as a see-saw and coupled to the magnetic actuator, caused the valve to open by displacing selected regions of a diaphragm and forcing the diaphragm into contact with a valve seat.
[0007] However, solenoid actuated valves can be dangerous in explosive surroundings. For example, they can be dangerous on oil drilling platforms or in use with chemicals in a chemical plant. The danger caused by solenoid valves arises from the fact that the electric current applied to the solenoid coils, for energizing the coils to provide electromagnetic flux to move the pistons under fault conditions can ignite flammable or explosive materials in the vicinity of the valves.
[0008] One solution to the problem was to limit the magnitude of the solenoid-actuating current to a level below the level which could possibly ignite a fire or cause an explosion, in a worst case scenario, within the particular hazardous environment where the valve was used. However, limitations on the amount of current that can be used to energize a solenoid places limitations on the size of the piston that can be moved as well as the speed and acceleration of the piston movement. Therefore, it was very difficult and expensive to obtain adequate solenoid activated valves suitable for many applications within hazardous areas.
[0009] Another solution was to provide valves that were actuated using permanent magnets rather than solenoids. For example, U.S. Pat. No. 4,942,852, entitled “Electro-Pneumatic Actuator,” issued to Richeson on Jul. 24, 1990, teaches a valve suitable for internal combustion engines. The actuator taught by Richenson was a pneumatically powered transducer for use as a valve mechanism actuator. The transducer had a piston which was powered by a pneumatic source and held in each of its extreme positions. Air control valves were held in their closed positions by pressured air and/or permanent magnet latching arrangements and the control valves are released to supply air to the piston. When the piston was thus released it was driven to the opposing extreme position by the permanent magnetic field. However, even though the Richeson valve used permanent magnet actuation, it was not completely free of electrical circuits.
[0010] U.S. Pat. No. 3,517,699, entitled “Magnetic-Pneumatic Proximity Switch,” issued to Marcum on Oct. 20, 1967, teaches a magnetic-pneumatic proximity switch. In the Marcum system, air flow was controlled by a valve without electrical circuit. Instead, a magnetic proximity switch was provided. The magnetic proximity valve taught by Marcum operated as a restriction device in a pneumatic circuit that opened and closed, thereby controlling a spool valve. The spool valve in turn controlled the flow of an operating fluid to or from a working piston and cylinder device.
[0011] U.S. Pat. No. 4,630,645, entitled “Pneumatic Switching Device, E.G., For Safeguarding Against Overpressure,” issued to Spa on Dec. 23, 1986, also taught a valve that could be actuated without any electrical current. In the Spa device, a piston was received in a bore of a housing. The piston had a narrowed portion between two end surfaces. Two seals were provided in the narrowed portion that acted cooperatively with seats projecting from the wall of the housing bore towards the piston axis. A compression spring acted on one end face of the piston. The other piston end face delimited a pressure chamber with the housing wherein the air valve was in communication with the pressure chamber. A pilot air aperture had a restriction opening into the chamber and an out flow aperture opened between both housing seats. A signal pressure aperture opened into the bore beyond each seat. The pivotal lever engaged an actuation pin of the air valve.
[0012] U.S. Pat. No. 4,964,424, entitled “Pneumatic Valve Assembly For Controlling A Stream of Compressed Air,” issued to Helbig on Oct. 23, 1990. The valve assembly taught by Helbig was adapted for controlling compressed air stream in response to a non-contacting actuation. It included a pivoted one-arm or double-arm lever, a permanent magnet on one side or on each of both sides of its pivotal axis and via a ferromagnetic or magnetic actuating member. The actuating member was moved into proximity of the permanent magnet or magnets by means of a plunger, causing a pilot orifice to be opened or closed. A pilot air stream flowed through the orifice for actuating a pilot piston to move a valve piston to positions in which the valve was opened or closed. Permanent magnets were provided on the lever on both sides of its pivotal axis. The permanent magnets were interconnected by a magnetic yoke. The magnetic yoke was oppositely poled so that a magnet which was moveable into the proximity of both permanent magnets outside the valve body constituted an actuating member that attracted one permanent magnet on the double-armed lever and repelled the other of the permanent magnets. European Publication EP0715109A1 also teaches a valve having a permanent magnet actuation mechanism.
[0013] All references cited herein are incorporated herein by reference in their entireties.
BRIEF SUMMARY OF THE INVENTION
[0014] A pneumatically actuated fluid control valve for permitting flow of a fluid from a valve inlet to a valve outlet includes a piston having a valve open piston position and a valve closed piston position for controlling the fluid flow and a piston actuator including a permanent magnet having magnetic flux for applying the magnetic flux to the piston. At least first and second piston actuator positions are provided for magnetically disposing the piston in a selected one of the valve open and valve closed positions. The pneumatically actuated fluid control valve is provided with a pneumatic actuator driving circuit for pneumatically disposing the piston actuator in the first and second piston actuator positions thereby pneumatically moving the piston from one to the other of the valve open and valve closed piston positions. The pneumatically actuated fluid control valve includes an annular valve assembly and the piston is disposed in the center of the annular valve assembly. A first valve assembly position is a normally closed valve assembly position and a positive air flow control signal into the magnet driving assembly adjusts the chamber volume to apply increasing magnet flux to the piston and to move the piston from the valve closed position to the valve open position. A second valve assembly position is a normally open valve assembly position and a positive air flow control signal into the magnet driving chamber adjusts the chamber volume to apply decreasing magnetic flux to the piston and to move the piston from the valve open position to the valve closed position. A further magnet driving chamber and a further air flow control signal can be provided for applying opposing pressures to the piston in accordance with two separate air flow control signals to apply a differential pressure to the piston actuator to control the actuator according to the difference in pressures.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0015] The invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein:
[0016] FIG. 1 shows a cross-sectional representation of the pneumatically actuated pilot valve of the present invention.
[0017] FIG. 2 shows an alternate embodiment of the pneumatically actuated pilot valve set forth in FIG. 1 .
[0018] FIG. 3 shows an alternate embodiment of the pneumatically actuated pilot valve set forth in FIG. 1 .
[0019] FIG. 4 shows a differential pressure diaphragm valve operated in accordance with a pilot signal provided by the pneumatically actuated pilot valve of FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
[0020] Referring now to FIG. 1 , there is shown the pneumatically actuated pilot valve 20 of the present invention. In response to an air flow control signal 28 applied to the pneumatically actuated pilot valve 20 , the pilot valve 20 provides a pilot signal outlet flow for use in controlling the opening and closing of a further fluid valve.
[0021] The pilot valve 20 includes a piston 60 disposed within a piston cylinder 36 . When the piston 60 is in its extreme downward position it presses against a valve seat 66 formed by an annular portion of the bottom of a valve seat chamber 64 . The pressure of the piston 60 against the valve seat 66 causes a fluid flow circuit between the pilot valve ports 22 , 26 to be interrupted. The piston 60 is sealingly biased in the closed position against the valve seat 66 by a piston spring 38 . The pneumatically actuated pilot valve 20 is thus a normally closed valve.
[0022] In order to open the pilot valve 20 and permit a fluid flow between the pilot valve ports 22 , 26 , the piston 60 must be moved upwardly against the closing force of the piston spring 38 . In order to move the piston 60 in this manner, an upward force is applied to the piston 60 by applying the magnetic flux of a permanent magnet 44 to the piston 60 . The permanent magnet 44 is disposed within a magnet assembly 40 . The magnet assembly 40 is an annular assembly disposed within the magnet assembly cavity 50 surrounding the piston cylinder 36 . An actuator spring 52 is disposed within the magnet assembly cavity 50 pressing against the magnet assembly 40 at its upper end and against an actuator spring seat 56 at its lower end in order to bias the magnet assembly 40 upward.
[0023] The permanent magnet 44 is moved toward the piston 60 by applying the positive air flow control signal 28 to the control inlet port 24 . When a positive air flow control signal 28 is driven into the control inlet port 24 , the magnet driving chamber 34 is expanded by the fluid pressure of the air flow control signal 28 . The expansion of the magnet driving chamber 34 forces the magnet assembly 40 downward and brings the permanent magnet 44 closer to the piston 60 against the force of an actuator spring 52 . The magnetic flux of the permanent magnetic 44 is thus applied to the piston 60 in response to the fluid signal applied to the control inlet port 24 . Continued travel of the permanent magnet 44 through the magnet cavity 50 causes the magnetic flux applied to the piston 60 to increase.
[0024] In response to the pressure of the positive air flow control signal 28 applied to the control inlet port 24 , the permanent magnet 44 travels a distance 48 through the magnet assembly cavity 50 . The increasing upward force applied to the piston 60 by the permanent magnet 44 as it travels the distance 48 eventually causes the piston 60 to be actuated. When the piston 60 is actuated, it separates from the valve seat 66 thereby permitting fluid to flow between the ports 22 , 26 by way of the valve seat chamber 64 . Thus valve 20 can be used as a stand above valve as well as a pilot valve.
[0025] When the positive fluid flow applied to the annular magnet driving chamber 34 is withdrawn, the downward force upon the magnet assembly 40 is decreased. This permits the actuator spring 52 to expand within the magnet assembly cavity 50 , thereby forcing the permanent magnet 44 in the upward direction. As the permanent magnet 44 travels upward the magnetic flux applied to the piston 60 is decreased. When the force applied to the piston 60 by the magnetic flux of the permanent magnet 44 decreases enough the downward force applied to the piston 60 by the piston spring 38 overcomes the upward force due to the magnetic flux, and the piston spring 38 sealingly forces the piston 60 against the valve seat 66 . When the piston 60 is sealingly pressed against the valve seat 66 the fluid circuit between the ports 22 , 26 of the pneumatically actuated fluid control valve 20 is interrupted and the pilot valve 20 is closed.
[0026] It will be understood that elements of the pneumatically actuated pilot valve 20 can cooperate to form a pneumatically actuated valve assembly 32 . The pneumatically actuated valve assembly 32 includes an annular valve assembly housing 30 which houses the magnet assembly 40 , the magnet driving chamber 34 and the actuator spring 52 . The control inlet port 24 is coupled to the valve assembly housing 30 . The entire valve assembly 32 fits over the piston cylinder 36 and is detachably secured to the pilot valve 20 in order for the pilot valve 20 to operate as described above.
[0027] Furthermore, when the valve assembly 32 is detached from the pilot valve 20 it can be removed from the piston cylinder 36 , inverted, and fit back over the piston cylinder 36 in its inverted position. The valve assembly 32 can then be detachably secured in its inverted position to provide a pneumatically actuated pilot valve that operates as described in detail below. Significantly, the detachable valve assembly 32 of the pilot valve 20 can be interchanged between its inverted and non-inverted positions without breaking the fluid circuit between the valve ports 22 , 26 .
[0028] Thus, the pilot valve 20 can be interchanged in this manner between a normally closed valve and a normally open valve as required by the user. Additionally, a solenoid valve can be converted into a pneumatically actuated valve using the valve assembly 32 . In order to make such a conversion the valve assembly 32 can be substituted for a solenoid actuator as found in many existing solenoid valves by merely removing a solenoid assembly originally provided with the solenoid valve and fitting the valve assembly 32 over the existing piston cylinder 36 of the solenoid valve. The method for attaching and detaching the valve assembly 32 is the conventional method used for solenoid valve assemblies, requiring the removal and replacement of a single nut (not shown).
[0029] Referring now to FIG. 2 , there is shown the pneumatically actuated pilot valve 80 . The pneumatically actuated pilot valve 80 is an alternate embodiment of the pneumatically actuated pilot valve 20 wherein the pneumatically actuated valve assembly 32 of the pilot valve 20 is inverted to provide the inverted pneumatically actuated valve assembly 92 of the pilot valve 80 .
[0030] The pilot valve 80 includes a piston 120 disposed within a piston cylinder 96 . When the piston 120 is in its extreme downward position it presses against a valve seat 126 formed by an annular portion of the valve seat chamber 124 . The pressure of the piston 120 against the valve seat 126 causes the fluid flow circuit between the pilot valve ports 82 , 86 to be interrupted. The piston 120 is maintained in a spaced apart relationship with the valve seat 126 by an upward force due to the magnetic flux of the permanent magnet 104 acting against the downward force of the piston spring 98 when the actuation spring 112 forces the magnet assembly 100 toward the bottom of the magnet assembly cavity 110 . The pneumatically actuated pilot valve 80 is thus a normally open valve.
[0031] The permanent magnet 104 is an annular magnet within the magnet assembly 100 . The magnet assembly 100 is disposed within the magnet assembly cavity 110 surrounding the piston cylinder 96 . The actuator spring 112 is disposed within the magnet assembly cavity 110 pressing against the magnet assembly 100 at its upper end and against an actuator spring seat 116 at its lower end in order to bias the magnet assembly 100 downwardly.
[0032] In order to close the pilot valve 80 and interrupt fluid flow between the pilot valve ports 82 , 86 , the piston 120 must be forced downward by the force of the piston spring 98 . In order to move the piston 120 in this manner, the upward force applied to the piston 120 by the magnetic flux of a permanent magnet 104 must be decreased by moving the permanent magnet 104 in the upward direction.
[0033] The permanent magnet 104 is moved upward away from the piston 120 by applying a positive air flow control signal 88 to the control inlet port 84 . When the positive air flow control signal 88 is driven into the control inlet port 84 , the magnet driving chamber 94 is expanded by the fluid pressure of the air flow control signal 88 . The expansion of the magnet driving chamber 94 caused by the air flow control signal 88 forces the magnet assembly 100 upward against the actuator spring 112 and moves the permanent magnet 104 away from the piston 120 . Upward travel of the permanent magnet 104 through the magnet cavity 110 causes the magnetic flux applied to the piston 120 by the permanent magnet 104 to decrease.
[0034] In response to the pressure of the positive air flow control signal 88 applied to the control inlet port 84 , the permanent magnet 104 travels a distance 108 through the magnet assembly cavity 110 . The decreasing force applied to the piston 120 by the permanent magnet 104 as it travels the distance 108 eventually allows the downward force applied by the piston spring 98 to overcome the upward force due to the magnetic flux of the permanent magnet 104 . This causes the piston 120 to be actuated. When the piston 120 is actuated, it is sealingly pressed against the valve seat 126 by the piston spring 98 thereby preventing fluid from flowing between the valve ports 82 , 86 .
[0035] When the positive fluid flow applied to the annular magnet driving chamber 94 is withdrawn, the upward force applied to the magnet assembly 100 is decreased. This permits the actuator spring 112 to expand within the magnet assembly cavity 110 , thereby forcing the permanent magnet 104 in the downward direction. As the permanent magnet 104 travels downward the magnetic flux applied to the piston 120 increases. When the force applied to the piston 120 by the magnetic flux increases enough the force of the piston spring 98 is overcome and the piston 120 separates from the valve seat 126 . When the piston 120 is separated from the valve seat 126 the fluid flow between the ports 82 , 86 of the pneumatically actuated fluid control valve 80 can resume.
[0036] Referring now to FIG. 3 , there is shown the pneumatically actuated pilot valve 140 . The pneumatically actuated pilot valve 140 is an alternate embodiment of the pneumatically actuated pilot valve 20 . The pilot valve 140 is provided with two control input ports 144 a,b which receive respective air flow control signals 148 a,b . The control input ports 144 a,b communicate with respective magnet driving chambers 154 a,b disposed on opposing sides of the magnet assembly 160 within the housing of the valve assembly 150 . The relative pressures of the air flow control signals 148 a,b thus determine the vertical position of the magnet assembly 160 within the valve assembly housing. As the relative pressures of the air flow control signals 148 a,b vary the magnet assembly 160 can travel a distance 168 .
[0037] When the pressure of the air flow control signal 148 b exceeds the pressure of the air flow control signal 148 a the magnet assembly 160 is moved to its upward position. Under these conditions magnetic flux from the permanent magnet 164 is not operatively applied to the piston 180 . Therefore, the piston spring 158 forces the piston 180 sealingly against the valve seat 186 , thereby preventing fluid flow between the valve ports 142 , 146 by way of the valve chamber 184 .
[0038] When the pressure of the air flow control signal 148 a is increased to exceed the pressure of 148 b the magnet assembly 160 travels downward and the magnetic flux applied to the piston 180 by the permanent magnet 164 increases, thereby applying an increasing upward force to the piston 180 . Eventually, the upward force applied to the piston 180 overcomes the downward force of the piston spring 158 and opens the pilot valve 140 . If the pressures of the air flow control signals 148 a,b are maintained equal to each other at this point the pilot valve 140 can remain open. When the magnet assembly 160 travels farther in the downward direction, the permanent magnet 164 closes the pilot valve 140 as previously described with respect to the pilot valve 20 .
[0039] Referring now to FIG. 4 , there is shown the differential pressure diaphragm valve 180 operating under the control of the pneumatically actuated pilot valve 20 . The differential pressure diaphragm valve 180 includes a valve housing 184 . The interior of the valve housing 184 is divided into an upper valve chamber 188 and a lower valve chamber 216 . The upper valve chamber 188 is separated from the lower valve chamber 216 by a diaphragm 200 .
[0040] The lower valve chamber 216 is provided with a valve inlet port 212 and a valve outlet port 224 for permitting fluid flow therebetween. A valve outlet pipe 228 within the lower valve chamber 216 can communicate with the interior of the lower valve chamber 216 at one end and with the valve outlet port 224 at its other end. The interior end 218 of the valve outlet pipe 228 sealingly presses against an annular area of the lower diaphragm side 208 at the diaphragm region 220 . The lower diaphragm side 208 presses against the inner end 218 of the valve outlet pipe 228 to thereby prevent the entry of fluid from the lower valve chamber 216 into the valve outlet pipe 228 and the outlet port 224 , thereby sealing the differential pressure diaphragm valve 180 .
[0041] The diaphragm 200 is provided with at least a leak hole 204 therethrough. The leak hole 204 through the diaphragm 200 causes the pressure in the upper valve chamber 188 to equalize with the pressure in the lower valve chamber 216 when the diaphragm valve 180 is closed. The pressure within the upper valve chamber 188 causes downward force to be applied to the upper diaphragm side 216 . The magnitude of the downward force thus applied is related to the pressure within the upper valve chamber 128 and the surface area of the upper diaphragm side 222 upon which the pressure is applied. The downward pressure upon the diaphragm 200 generated in this manner forces the diaphragm 200 toward the inner end 218 of the valve outlet pipe 228 .
[0042] The pressure of the fluid within the lower valve chamber 216 applies an upward force to the lower diaphragm side 208 . The upward force applied to the lower diaphragm side 208 in this manner is related to the pressure of the fluid within the lower valve chamber 216 and the surface area over which the pressure is applied. However, the pressure applied to the lower diaphragm side 208 does not operate upon as much surface area as the pressure applied to the upper diaphragm side 222 , because the inner end 218 of the valve outlet pipe 228 prevents pressure from being applied to the diaphragm 200 within the diaphragm region 220 . Thus, the pressure equalized between the valve chambers 188 , 216 by the leak hole 204 results in more downward force being applied to the diaphragm 200 than upward force. This differential downward force on the diaphragm 200 is the force which sealingly presses the diaphragm 200 against the inner end 218 of the valve outlet pipe 228 and closes the differential pressure diaphragm valve 180 .
[0043] When the air flow control signal 28 is applied to the control inlet port 24 of the pneumatically actuated pilot valve 20 , fluid is removed from the upper valve chamber 188 by way of the fluid line 196 and received into the valve inlet port 22 of the pneumatically actuated pilot valve 20 . As fluid is removed from the upper valve chamber 188 , fluid leaks into the upper valve chamber 188 from the lower valve chamber 216 by way of the leak hole 204 in the diaphragm 200 .
[0044] If the number and size of the leak holes 204 are selected such that fluid leaks through the leak holes 204 into the upper valve chamber 188 at a rate that is slower than the rate at which the fluid is removed from the upper valve chamber 188 through the feed line 196 , the pressure within the upper valve chamber 188 drops. As the pressure within the upper valve chamber 188 drops the amount of downward force applied to the upper diaphragm side 222 drops. Eventually, the downward force applied to the upper diaphragm side 222 becomes less than the upward force applied to the lower diaphragm side 208 . When this happens the diaphragm 200 is deflected upward and the diaphragm region 220 moves away from its sealing contact with the inner end 218 of the valve outlet pipe 228 .
[0045] When the diaphragm 200 is no longer pressing against the inner end 218 fluid within the lower valve chamber 216 can enter the valve outlet pipe 228 . The fluid in the outlet pipe 228 flows through the valve outlet pipe 228 and exits the diaphragm valve 180 by way of the outlet port 224 , provided that the upstream pressure of the diaphragm valve 180 is greater than the downstream pressure. Thus, the pneumatically actuated pilot valve 20 can control the differential pressure diaphragm valve 180 without the use of electricity and the pilot valve 20 is therefore intrinsically safe for controlling valves when disposed in hazardous environments.
[0046] While the invention has been described in detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
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A pneumatically actuated fluid control valve includes a piston and a piston actuator including a permanent magnet. First and second piston actuator positions for magnetically disposing the piston in valve open and valve closed positions are provided. A pneumatic actuator driving circuit pneumatically moves the piston actuator from one to the other of first and second piston actuator positions to dispose the piston in the open and closed positions. The valve includes an annular valve assembly. One valve assembly position is a normally closed position and a positive air flow control signal moves the piston to open the valve. Another valve assembly position is a normally open position and a positive air flow control signal moves the piston to close the valve.
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BACKGROUND
[0001] Radio Frequency (RF) signals and components are employed in a variety of devices, including mobile communication devices such as mobile telephones. One type of commonly employed RF component is an RF attenuator, which is sometimes employed to control an RF signal level in a device that employs RF signals.
[0002] FIG. 1 illustrates a basic configuration of a series-shunt field effect transistor (FET) attenuator 100 . Attenuator 100 includes an input port 105 and an output port 115 . Attenuator 100 also includes a first series attenuation branch, or arm, including a first series field effect transistor 110 , connected in series with a second series attenuation branch, or arm, including a second series field effect transistor 120 , between input port 105 and output port 115 via an intermediate node 117 . Also, a shunt attenuation branch, or arm including a shunt field effect transistor 130 is connected between intermediate node 117 and ground.
[0003] Attenuator 100 includes two attenuation control ports 125 and 135 which receive a series attenuation control signal Vg_series and a shunt attenuation control signal Vg_shunt, respectively. The series attenuation control signal Vg_series is applied to the gates of first and second series field effect transistors 110 and 120 , and the shunt attenuation control signal Vg_shunt is applied to the gate of shunt series field effect transistor 130 .
[0004] Effectively, first and second series field effect transistors 110 and 120 and shunt field effect transistor 130 are operated as voltage controlled impedances to attenuate an input signal, particularly an RF input signal, received at input port 105 and to provide the attenuated signal at output port 115 . The voltages Vg_series and Vg_shunt are selected so that they operate in combination to provide a desired attenuation (e.g., X dB) while also maintaining desired input and output impedance values (e.g., 50Ω) within a desired tolerance.
[0005] Unfortunately, maintaining the relationship between Vg_series and Vg_shunt to satisfy these requirements can be complicated.
[0006] FIG. 2 shows a schematic diagram of an attenuator 200 that is designed to try to address this problem. Attenuator 200 includes an input port 205 and an output port 215 . Attenuator 200 also includes a first series attenuation arm, including a first series field effect transistor 210 , connected in series with a second series attenuation arm, including a second series field effect transistor 220 , between input port 205 and output port 215 via an intermediate node 217 . Also, a shunt attenuation arm including a shunt field effect transistor 230 is connected between intermediate node 217 and ground. Attenuator 200 includes one attenuation control port 225 which receive a series attenuation control signal Vg_series. Attenuator 200 also includes analog-to-digital converter (ADC) 240 , look-up table 250 , and digital-to-analog converter (DAC) 260 .
[0007] In attenuator 200 , for each attenuation value, X, there exists a value of the attenuation control signal voltage Vg_series(X), and a corresponding value for Vg_shunt(X), which together yield the desired attenuation X, while also maintaining the desired input and output impedances. When attenuator 200 is designed and constructed, for each desired attenuation value X the corresponding values of Vg_series(X) and Vg_shunt(X) are determined that also maintain the desired input/output impedances. Vg_series(X) and Vg_shunt(X) are each “digitized”—i.e., converted to digital words. The digital word for Vg_shunt(X) is then stored in look-up table 250 at an “address” corresponding a digital word for Vg_series(X).
[0008] In operation, when a particular attenuation value X is to be selected and applied by attenuator 200 to an input signal (e.g., an RF input signal), then the corresponding attenuation control signal voltage Vg_series(X) is applied to attenuation control port 225 . Vg_series(X) is converted by ADC 240 to a digital address for addressing look-up table 250 . Look-up table 250 then outputs a digital word representing the corresponding value for Vg_shunt(X). Finally, DAC 260 converts the digital word from look-up table 250 to produce the analog voltage Vg_shunt(X) which is then applied to shunt field effect transistor 230 .
[0009] However, the attenuator 200 of FIG. 2 is complicated, requiring a number of additional circuits beyond the simple attenuator 100 of FIG. 1 . Furthermore, attenuator 200 lacks provisions for addressing variations in the attenuator response due to process variations and temperature changes.
[0010] FIG. 3 shows a schematic diagram of another attenuator 300 that is also designed to try to address the issue of maintaining a proper relationship between Vg_series and Vg_shunt to achieve desired attenuation values and maintain the input and output impedances within a desired range. Attenuator 300 includes an input port 305 and an output port 315 . Attenuator 300 also includes a first series attenuation branch, including a first series field effect transistor 310 , connected in series with a second series attenuation branch, including a second series field effect transistor 320 , between input port 305 and output port 315 via an intermediate node 317 . Also, a shunt attenuation branch including a shunt field effect transistor 330 is connected between intermediate node 317 and ground. Attenuator 300 includes one attenuation control port 325 which receive a series attenuation control signal Vg_series.
[0011] Attenuator 300 also includes a “dummy attenuator” or “replica attenuator” 340 . Replica attenuator 340 includes a first replica series attenuation branch, including a first replica series field effect transistor 360 , connected in series with a second replica series attenuation branch, including a second replica series field effect transistor 370 , between replica attenuator input load 304 and replica attenuator output load 314 via an intermediate node 367 . Also, a replica shunt attenuation branch including a replica shunt field effect transistor 380 is connected between intermediate node 367 and ground.
[0012] Attenuator 300 further includes an operational amplifier 390 having a non-inverting input connected to a supply voltage 308 through a resistor divider comprising resistors 324 and 334 . The inverting input of operational amplifier 390 is connected to the replica attenuator input load 304 . Operational amplifier 390 can be integrated into the same chip as attenuator field effect transistors 310 , 320 and 330 , or it can be provided off-chip
[0013] Operationally, series attenuation control signal Vg_series is provided to control the series field effect transistors 310 and 320 , and also to control the replica series field effect transistors 360 and 370 . Through feedback operation with replica attenuator 340 , operational amplifier 390 outputs a shunt attenuation control signal Vg_shunt to replica shunt field effect transistor 380 to maintain the input and output impedances of replica attenuator 340 to match the impedances of input and output loads 304 and 314 . The same shunt attenuation control signal Vg_shunt output by operational amplifier 390 is coupled to shunt field effect transistor 330 . By an appropriate selection of scaling for replica field effect transistors 360 , 370 and 380 versus attenuator field effect transistors 310 , 320 and 330 , and for input and output loads 304 and 314 versus the source and load impedances for input and output ports 305 and 315 , the operational amplifier 390 will output a value for shunt attenuation control signal Vg_shunt that will maintain the input and output impedances at attenuator 300 at the desired values.
[0014] However, attenuator 300 has some drawbacks, including the added size and complexity of replica attenuator 340 and operational amplifier 390 .
[0015] What is needed, therefore, is a relatively uncomplicated attenuator. What is further needed is an attenuator with a single attenuator control voltage input terminal which is relatively compact and which is relatively insensitive to process and temperature variations.
SUMMARY
[0016] In an exemplary embodiment, an attenuator comprises: an input port, an output port, an attenuation control port, and first and second supply voltage. The attenuator also comprises: a first series attenuation branch, including a first field effect transistor, connected between the input port and an intermediate node; a second series attenuation branch, including a second field effect transistor, connected between the node and the output port; a shunt attenuation branch, including a third field effect transistor, connected between the intermediate node and the supply voltage connection, a gate of third field effect transistor receiving the attenuation control signal from the attenuation control port; and a bias control circuit. The bias control circuit comprises a fourth field effect transistor receiving at a gate thereof the attenuation control signal from the attenuation control port, and having a first terminal connected to the first supply voltage, and a resistor connected between a second terminal of the fourth field effect transistor and the second supply voltage. The voltage at the second terminal of the fourth field effect transistor is coupled to gates of the first and second field effect transistors to supply a bias voltage thereto in response to the attenuation control signal.
[0017] In another exemplary embodiment, an attenuator comprises: one or more series attenuation branches comprising one or more series field effect transistors, each having a gate; one or more shunt attenuation branches comprising one or more shunt field effect transistors, each having a gate; and a bias control field effect transistor. The bias control field effect transistor receives at its gate a first bias control signal and in response thereto produces at one of its drain and source terminals a second bias control signal. Either the first bias control signal is coupled to the gates of the one or more series field effect transistors, and the second bias control signal is coupled to the gates of the one or more shunt field effect transistors; or the first bias control signal is coupled to the gates of the one or more shunt field effect transistors, and the second bias control signal is coupled to the gates of the one or more series field effect transistors.
[0018] In yet another exemplary embodiment, a method is provided for attenuating a signal. The method comprises: providing one or more series attenuation branches comprising one or more series field effect transistors each having a gate; providing one or more shunt attenuation branches comprising one or more shunt field effect transistors each having a gate; receiving a first bias control signal and providing the bias control signal to a bias control field effect transistor; at the bias control field effect transistor, producing from the first bias control signal a second bias control signal having a voltage which changes in an opposite direction with respect to a change in voltage of the first bias control signal; and either: (1) coupling the first bias control signal to the gates of each of the one or more series field effect transistors, and the second bias control signal is applied to the gates of the one or more shunt field effect transistors; or (2) coupling the first bias control signal is to the gates of the one or more shunt field effect transistors, and the second bias control signal is applied to the gates of the one or more series field effect transistors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The exemplary embodiments are best understood from the following detailed description when read with the accompanying drawing figures. It is emphasized that the various features are not necessarily drawn to scale. In fact, the dimensions may be arbitrarily increased or decreased for clarity of discussion. Wherever applicable and practical, like reference numerals refer to like elements.
[0020] FIG. 1 shows a schematic diagram of an attenuator.
[0021] FIG. 2 shows a schematic diagram of another attenuator.
[0022] FIG. 3 shows a schematic diagram of yet another attenuator.
[0023] FIG. 4 shows a schematic diagram of one embodiment of an attenuator which has a single attenuation control port.
[0024] FIG. 5 shows a schematic diagram of another embodiment of an attenuator which has a single attenuation control port
[0025] FIG. 6 illustrates an input impedance characteristic of the attenuator of FIG. 5 as a function of attenuator control voltage.
DETAILED DESCRIPTION
[0026] In the following detailed description, for purposes of explanation and not limitation, example embodiments disclosing specific details are set forth in order to provide a thorough understanding of an embodiment according to the present teachings. However, it will be apparent to one having ordinary skill in the art having had the benefit of the present disclosure that other embodiments according to the present teachings that depart from the specific details disclosed herein remain within the scope of the appended claims. Moreover, descriptions of well-known apparati and methods may be omitted so as to not obscure the description of the example embodiments. Such methods and apparati are clearly within the scope of the present teachings.
[0027] As used herein, the term “radio frequency” or “RF” pertains to VHF, UHF, SHF and even millimeter wave frequencies to the extent that technology permits the devices and circuits disclosed herein to be fabricated and operated at such frequencies. Also, unless otherwise noted, when a first device is said to be connected to a second device, this encompasses cases where one or more intermediate devices may be employed to connect the two devices to each other. However, when a first device is said to be directly connected to a second device, this encompasses only cases where the two devices are connected to each other without any intermediate or intervening devices. Similarly, when a signal is said to be coupled to a device, this encompasses cases where one or more intermediate devices may be employed to couple the signal to the device. However, when a signal is said to be directly coupled to a device, this encompasses only cases where the signal is directly coupled to the device without any intermediate or intervening devices.
[0028] FIG. 4 shows a schematic diagram of one embodiment of an attenuator 400 which has a single attenuation control port. Attenuator 400 includes an input port 405 and an output port 415 . Attenuator 400 also includes a first series attenuation branch, or arm, including a first series field effect transistor 410 , connected in series with a second series attenuation branch, or arm, including a second series field effect transistor 420 , between input port 405 and output port 415 via an intermediate node 417 . Also, a shunt attenuation branch, or arm, including a shunt field effect transistor 430 is connected between intermediate node 417 and ground.
[0029] Attenuator 400 includes a single attenuation control port 425 which receives a bias control signal Vg_shunt.
[0030] Attenuator 400 also includes a bias control circuit 440 . Bias control circuit 440 includes a bias control field effect transistor 450 and a resistor 404 , which are connected in series to a supply voltage 408 .
[0031] As can be seen in FIG. 4 , bias control circuit 440 operates to receive a first bias control signal Vg_shunt which is also coupled to shunt field effect transistor 430 , and to produce therefrom a second bias control signal Vg_series to be coupled to the gates of first and second series field effect transistors 410 and 420 . In particular, the same voltage Vg_shunt which is coupled to the gate of shunt field effect transistor 430 is also coupled to the gate of bias control field effect transistor 450 . One terminal (e.g., the drain) of bias control field effect transistor 450 outputs the second bias control signal Vg_series which exhibits a voltage which changes in an opposite direction with respect to a change in voltage of the first bias control signal Vg_shunt which is coupled to the gate of bias control field effect transistor 450 .
[0032] The exact relationship between the first bias control signal Vg_shunt and second bias control signal Vg_series is governed by proper selection of supply voltage 408 , resistor 404 , and the size of bias control field effect transistor 450 . In particular, the supply voltage 408 , resistor 404 , and the size of bias control field effect transistor 450 are selected in concert to yield the minimum variation in attenuator port impedance from the desired value, as a function of attenuation value. The selection of supply voltage 408 , resistor 404 , and the size of bias control field effect transistor 450 to produce the desired characteristics can be easily accomplished by one skilled in the art in a very short time using conventional design tools.
[0033] In operation, input port 405 receives an input signal that is to be attenuated. Typically, the input signal is an RF signal. Also, single attenuation control port 425 receives first bias control signal Vg_shunt having a voltage selected to provide a desired attenuation to the input signal. First bias control signal Vg_shunt is coupled to the gate of shunt field effect transistor 430 , and also to the gate of bias control field effect transistor 450 . The drain of bias control field effect transistor 450 becomes the second bias control signal Vg_series and is coupled to the gates of first and second series field effect transistors 410 and 420 . Field effect transistors 410 , 420 and 430 operate, in response to corresponding bias control voltages, as voltage controlled impedances. The voltage of the first bias control signal Vg_shunt biases shunt field effect transistor 430 to present a particular shunt impedance to ground for the RF input signal, and the voltage of the second bias control signal Vg_series biases series field effect transistors 410 and 420 each to present a particular series impedance to the RF input signal. As a result of the selected series and shunt impedances of field effect transistors 410 , 420 and 430 , the RF input signal is attenuated and output at output terminal 415 . Furthermore, due to the proper selection of supply voltage 408 , resistor 404 , and the size of bias control field effect transistor 450 , Vg_series is generated such that the input and output impedances of attenuator 400 are set to a desired value (e.g., 50Ω) within a desired tolerance (e.g., 45-63Ω) over the range of attenuation values.
[0034] In one particular embodiment: first and second series field effect transistors 410 and 420 , and shunt field effect transistor, are each of a size of 200 μm; supply voltage 408 has a voltage of 5V; resistor 404 has a value of 15 kΩ; and bias control field effect transistor 450 has a size of 20 μm.
[0035] In a beneficial arrangement, all of the field effect transistors 410 , 420 , 430 and 450 and resistor 404 are fabricated in a vicinity to each other in an integrated circuit. In this case, process and temperature variations in the attenuator field effect transistors 410 , 420 and 430 will be mirrored in bias control field effect transistor 450 .
[0036] FIG. 5 shows a schematic diagram of another embodiment of an attenuator 500 which has a single attenuation control port 425 . Attenuator 500 is similar to attenuator 400 , and like-numbered elements are the same. For brevity, only the differences between attenuator 500 and attenuator 400 will now be described.
[0037] In attenuator 500 , the first bias control signal Vg_shunt is coupled to the gate of shunt field effect transistor 430 via a corresponding gate resistor 536 , and the second bias control signal Vg_series is coupled to the gates of first and second series field effect transistors 410 and 420 via corresponding gate resistors 516 and 526 . Also, the first bias control signal Vg_shunt is coupled to the gate of bias control field effect transistor 450 via a corresponding gate resistor 556 . Attenuator 500 also includes first and second shunt resistors 513 and 523 each connected in parallel across a source and drain of a corresponding one of the first and second field effect transistors 410 and 420 . First and second shunt resistors 513 and 523 allow first and second field effect transistors 410 and 420 to be operated in a pinch-off condition without presenting an undesirably high impedance to the external circuitry. In a beneficial arrangement, resistors 516 , 526 , 536 and 556 all have relatively high resistance values (e.g., 10 kΩ), and first and second shunt resistors 513 and 523 each have a same value as the desired port impedance (e.g., 50Ω).
[0038] FIG. 6 shows an input port impedance characteristic of the attenuator of FIG. 5 as a function of attenuator control voltage (e.g., Vg_shunt). It can be seen from FIG. 6 that the input impedance only varies from about 45-63Ω across a wide range of attenuation control voltage. This implies a VSWR of less than about 1.3:1, which represents a good match.
[0039] Although the embodiments illustrated in FIGS. 4 and 5 are in a so-called “T” configuration with a single shunt attenuation branch disposed between two series attenuation branches, the invention is not so limited. The attenuator could include additional series and shunt branches while still operating within the principles disclosed above. Also, while the particular embodiment derives a Vg_series bias control voltage for series attenuation transistors from a Vg_shunt bias control voltage for a shunt attenuation transistor, in an alternative arrangement the Vg_series bias control voltage could be applied to a bias control transistor to develop therefrom the Vg_shunt bias control voltage.
[0040] While exemplary embodiments are disclosed herein, one of ordinary skill in the art appreciates that many variations that are in accordance with the present teachings are possible and remain within the scope of the appended claims. The embodiments therefore are not to be restricted except within the scope of the appended claims.
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An attenuator includes one or more series attenuation branches including one or more series field effect transistors (FETs) each having a gate; one or more shunt attenuation branches including one or more shunt FETs each having a gate; and a bias control FET. The bias control FET receives at its gate a first bias control signal and in response thereto produces at one of its drain and source terminals a second bias control signal. Either the first bias control signal is coupled to the gates of one or more series FETs, and the second bias control signal is coupled to the gates of the one or more shunt FETs; or the first bias control signal is coupled to the gates of the one or more shunt FETs, and the second bias control signal is coupled to the gates of the one or more series FETs.
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BACKGROUND OF THE INVENTION
While building construction, as an art, has been well developed through the literature and in practice, specialized constructions continue to be developed. In the present invention, standard building construction techniques are blended with modern entertainment technologies to produce an integrated entertainment center.
Auditoria and the like have been classed in Class 52, Subclass 6, Auditorium Structures. Nothing in the recent art in this class-subclass appears in conflict with the present invention. The patents found in said class-subclass appear to be constrained to systems for the public display of motion pictures, television, or live presentations to the general public. Many are concerned with multiple auditoria, with central display or control facilities.
Class 52, subclass 194 was considered as an alternate source of prior art. No apparent conflicts were found among the sound chambers of said class. Class 272, Subclass 2, et seq., were also reviewed as containing amusement structures.
The present invention appears, from the preliminary search, to be one of first impression, in that no prior art was discovered that provides for a small entertainment center structural addition to residential structures. The further incorporation of a suite of entertainment systems integrally designed into said structure, provides additional novelty and usefulness, as will be more particularly described hereinbelow.
SUMMARY OF THE INVENTION
The present invention provides a housing structure to accommodate a suite of audio and visual home entertainment devices. The structure is basically configured as rhomboidal prism, having two side walls, an end wall at the narrow end, and a planar roof sloped up from the narrow end. The fourth side is formed from the existing exterior wall of the residence to which this structure is added. The roof also attaches to the existing reference residential structure, the total forming a completely enclosed area. Access is provided from the existing residential structure by door means, directly into the addition. Additional ingress and egress may be provided to the exterior by one or more door means through the side walls of the addition.
In construction, the roof is supported by simple truss members placed generally parallel to the existing residential structure's exterior wall to which this addition is attached.
The internal construction of this structure includes acoustical materials on walls and ceiling such that the sound emanating from the several systems of the integrated entertainment suite are not distorted and are audible from each position within the room herein. Necessary electrical wiring is provided to power the several systems, room lights, and to conduct the sound from such systems to a series of speakers appropriately situated.
The integrated systems center about a large screen projection television system placed such that the viewing screen forms the major portion of the end wall at the narrow end of the structure. The wall areas to the right and left of said screen are occupied by the video system speaker, if such system is adapted to remote speakers. Space is also provided, in the form of shelves, for stereophonic sound systems, their speakers, indirect lighting, and for tapes and records for such systems. The end wall area below the viewing screen is adapted for incorporation of a video recorder system.
The remaining walls of the video room addition may be configured to the consumers taste to provide for bookcases and the like, which features are not part of this invention.
The constraints on the shape of the rhomboidal base area of the herein video room arise from the maximum angle of spectator viewing capability of present projection television systems.
The principal embodiment envisioned herein consists of the room addition and integrated projection television system, together with capability for the installation of the other mentioned systems.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective of the exterior of the video room, with a portion of the interior visible through the absent wall.
FIG. 2 is a plan view illustrating the shape of the video room.
FIG. 3 is an exterior side elevation of the video room.
FIG. 4 is an end elevation, showing the interior of the video room, as taken from its plane of attachment to the reference residence.
FIG. 5 is an exterior side elevation, illustrating one mode of attachment to a reference residence.
FIG. 6 is a sectional plan view of the interior of the video room, taken from 6--6 of FIG. 3.
FIG. 7 is an interior elevation view of the video room, taken from 7--7 of FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, wherein like reference characters designate like or corresponding parts of the several figures, the preferred embodiment and its variations shall be described. It is to be noted that specific details shown in the several figures are representative and may have differing proportions dependent upon building codes in effect at the several sites of construction of this invention.
Referring now to FIG. 1, the video room addition 12 is shown as detached from the exterior of an existing residential structure. Having placed an appropriate footing and floor slab or structure, according to the appropriate building codes applicable to the situs of the construction of the present invention, the said video room 12 is configured thereon to have two vertically oriented side walls 14, 14', a roof structure 16, and an end wall 18. Ingress and egress may be provided by door means 30, as well as through a door or portal fabricated into the exterior wall of the referenced existing residential structure. The plane formed by the ends of the walls 14, 14' and the roof structure 16, identified in FIG. 1 as the end surface 42, forms the surface of attachment of the video room 12 to the referenced existing residence structure.
Referring now to FIG. 2, the roof area 16 of the video room 12 is shown, in plan view, to be configured as a rhombus, such that the two side walls 14, 14' converge in separation from the house attachment surface 42 to the end wall 18. The roof 16 is of a generally planar structure and is supported by truss members spanning between the side walls 14, 14' and supported thereby.
Referring now to FIG. 3, an exterior elevation view of wall 14, it is noted that the height of the wall decreases from the end bearing the house attachment surface 42 to the end wall 18, thereby providing that the roof structure 16 shall slope away from the referenced existing residence structure. The elevation of the side walls 14, 14', at the surface of attachment 42 is constrained to that available from the design of the referenced house 40, to include eaves and facia. At the outer end of said side walls 14, 14', at their juncture with the end wall 18, their elevation shall be not less than seven feet to accommodate the internal systems placement, and a standing person of reasonable height.
FIG. 5, illustrating the exterior elevation view of wall 14', likewise illustrates the roof slope feature and, further, provides a ghost partial illustration of the referenced existing residence structure 40, thereby defining the surface of attachment 42. It further shows the floor surface or slab 32 for reference purposes.
Referring now to FIG. 4, the interior view of the video room 12 shows that the end wall 18 is of a generally rectangular shape and is of sufficient width to accommodate the interior systems areas and the projection screen 20. Said screen 20 is located central to said wall 18. Said screen 20, in general, has curvature approaching that of the central region of a large parabolic surface. Current models envisioned for inclusion utilize screens having a diagonal dimension in excess of 72 inches.
Also situated along said back wall 18, are a series of shelves 24, 24', which are utilized for speakers 26, 26', stereo sound systems, indirect lighting, light displays, and book, tape and record storage.
The projector 22 for the projection television system may be placed appropriately within the room area, as constrained by the projection system incorporated.
The interior of the side walls 14, 14' and the roof 16 are treated with appropriate acoustical materials to provide high sound qualities throughout the room. Specific details are not herein provided since such design is beyond the scope of this invention and such techniques are well known.
Referring now to FIGS. 6 and 7, it is shown that the sides 28, 28' of the shelf structures 24, 24' form a central alcove area along the end wall 18, into which is placed the viewing screen 20. The orientations of the side walls 14, 14' relative to the normals to the exterior of the referenced house at the surface of attachment 42 are such that the interior lines of sight from points near the interior surfaces of said walls 14, 14' to the viewing screen 20 do not exceed the angular viewing capability of television projection systems, typically 30 to 35 degrees total included angle.
All construction throughout the walls 14, 14', and 18, and the roof 16 shall be adapted to the requirements of the building codes of the situs of the construction of this video room 12, however, such variations shall not influence the general shape of the video room nor the nature of the incorporated systems.
Fixed seating facilities are not provided, since each user will have his or her preferred arrangement.
Additional speakers, connected to the several systems by wiring within the walls, may be strategically placed throughout the video room.
A retractable motion picture screen may be hung from the ceiling or incorporated within the roof construction for additional entertainment capability.
Although the invention has been herein shown and described in what are conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention, which is therefore not to be limited to the illustrative details disclosed.
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The art of building construction, and more particularly with the design and implementation of a specialized room addition to a typical single family residence wherein the addition contains not only the room construction, but also a suite of entertainment systems integrally constructed therein. The primary system included is a large screen projection television and its associated audio systems. Ancillary entertainment systems are included, as desired by the consumer.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part application that claims the benefit of U.S. patent Ser. No. 14/058,323 filed on Oct. 21, 2013, entitled “Dual Compartment Walk-in Bathtub,” which claims the benefit of U.S. Provisional Application No. 61/719,120 filed on Oct. 26, 2012, entitled “Walk-in Bathtub.” The above identified patent applications are herein incorporated by reference in their entirety to provide continuity of disclosure.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to walk-in bathtubs for those with reduced mobility that allow for pre-filling thereof prior to entry. More specifically, the present invention pertains to a walk-in bathtub that allows a user to fill the tub without being positioned therein while having the entry door in an open position. The device facilitates setting the bathtub as would be possible with a traditional tub, whereafter the user can enter the bathtub without climbing over the bathtub wall.
[0004] For those with reduced mobility, including the elderly and disabled, moving into and exiting from a typical bathtub can be difficult. Most bathtubs include a raised wall used to contain the water within the bathtub interior. This wall presents an obstacle for some users as it requires the user to step over the wall to enter the bath. This can be difficult and even dangerous for those with reduced mobility from injury or impairment, as the user has to step over the bathtub wall one leg at a time while maintaining balance on a single foot. While this is readily accomplished for one of normal health and strength, physical impairments and age can quickly diminish one's capacity to engage in such routine activities.
[0005] To improve the safety and reduce the burden of exiting and entering a bathtub for those with limited mobility, different types of walk-in bathtubs are available that assist stepping into and exiting from a bathtub interior that do not require the user to step over an obstacle. The ability to walk directly into the shower without lifting a leg or shifting one's weight drastically reduces the chances of injury, and further enables one to easily enter or exit the shower without straining or slipping. Generally these bathtubs include an open layout or a raised wall having an entry door therealong to provide through-access. The open layout design is mostly used in shower stall settings, while entry doors are disposed on fillable bathtubs structures.
[0006] While many walk-in bathtubs exist in the art and are readily available to consumers, these devices retain an inherent drawback that has to be resolved, Notably, when filling a walk-in bathtub with bath water, the door must be in a closed position in order to retain the water therein. Generally the door is lined with a seal or gasket to prevent water leakage therethrough from the tub interior. When in a closed position, the door supports the pressure exerted on the door interior and the tub can be filled for the user to soak in the tub interior as desired.
[0007] This arrangement, while useful for providing an entryway into the tub, does not allow the user to first set the bathtub by filling the same and bringing the bath water to an appropriate temperature before entering thereinto. If the user desires to set the water before entering the bathtub, the door must be a closed position and the tub therefore returns to a traditional tub arrangement with a uniform outer wall for the user to climb over. This defeats the purpose of the entry door and therefore makes the exercise of first setting the tub not feasible for those with mobility problems who may require a walk-in arrangement in the first place.
[0008] The present invention is submitted as a new and novel walk-in bathtub arrangement that serves a long-felt need in the art. Specifically, the present invention contemplates a walk-in bathtub that is capable of being set before the user enters thereinto, wherein the user can fill the tub interior, place desired soaps and treatments into the water, and ensure a desired water temperature before being in the tub. The bathtub includes one or more removable dam elements that segment the tub interior into two or more compartments, whereby one compartment can be filled while the other compartment act as an operable entryway, operable seating area, or water-fillable compartment after the bathwater in the first compartment is set. This allows the user to set the bathwater prior to entry thereinto without being forced to close the entry door, while two separate drains and dam element allow the user to exit the tub from the second compartment while the first compartment is still being drained.
[0009] 2. Description of the Prior Art
[0010] Devices have been disclosed in the prior art that relate to walk-in bathtub arrangements and entry doors therefor. These include devices that have been patented and published in patent application publication, and generally relate to different tub arraignments, those with operable entry doors, and other with interior seat accommodations. The following is a list of devices deemed most relevant to the present disclosure, which are herein described for the purposes of highlighting and differentiating the unique aspects of the present invention, and further highlighting the drawbacks existing in the prior art.
[0011] One such device in the prior art is U.S. Pat. No. 7,299,509 to Neidich, which discloses a door assembly for a walk-in bathtub, wherein the device comprises a first track that accommodates a gasket along the length of the door frame, and a second track for mounting the door hinge. The gasket forms a tight seal between the door and the walk-in bathtub, whereby the door will not leak fluid when the tub is filled with water. While teaching a novel door for a walk-in bathtub and disclosing a bathtub of the walk-in type, the Neidich device fails to teach the novel configuration of the present invention, which provides a user with flexibly with regard to preparing, entering, and thereafter using the walk-in bathtub.
[0012] Similar to the Neidich device, U.S. Pat. No. 8,375,478 to Luo discloses a walk-in bathtub having a bathtub frame, a doorjamb, a hingedly attached door attached to the door jamb, and a gasket disposed between the door and door jamb to prevent leaks therefrom. To secure the door to the door jamb, and thus create a flush seal that encloses the tub water within the bathtub frame, a movable handle and latching pin secure the door against the gasket. The Luo device, similar to the Neidich device, teaches of a new door and seal for a walk-in bathtub, and fails to disclose the novel operating functions and structural elements of the present invention.
[0013] Further related to walk-in bathtub doors is U.S. Patent Publication No. 2010/0263119 to Neidich, which describes a door assembly having a first and second door mount to provide a double axis hinge for the door connecting to the bathtub threshold. The double axis hinge allows the door to be removed from its closed position and placed in a position that faces the interior of the door towards the bathtub when in an open position, rather than a single hinge door that swing open in an arcing fashion. Similar to the aforementioned devices related to walk-in bathtub doors, the Neidich double axis door does not contemplate the novel features of the present invention and is limited to a new door type for walk-in bathtubs.
[0014] Finally, U.S. Patent No. 2005/0102746 to Wright discloses a walk-in bathtub that includes a unitary body forming an elevated seat portion and a lower floor region. A water-tight door is fitted to a door frame on the unitary body and adjacent to the lower floor region, whereby water can be filled into the floor region for the user to bath. A drain hole is positioned on the lower floor region to drain the bathwater between users and to allow for opening the door. The Wright device discloses a seated bathtub having a seat portion and lower leg portion. The Wright device is not capable of filling until the user has entered the bathtub and closed the water-tight door. The present invention contemplates an assembly that allows the user to fill the bathtub with water and prepare the same at a given temperature before entering for bathing activities. The user can freely enter and exit the bathtub, whereby one or more dam elements prevent water from entering the back portion of the tub and pressing against the entry door.
[0015] The present invention provides a walk-in bathtub that allows the tub to be first set and filled before the user enters the bathtub interior. The bathtub of the present invention can be utilized as a standup shower, as a soaking tub, or as a bathtub with an internal seat therein. Overall, the assembly provides an elderly or injured user with a more convenient means of taking baths or showers, whereby the bath can be filled and set prior to entry and the bathtub can be utilized in a number of different configurations.
[0016] It is submitted that the present invention is substantially divergent in design elements from the prior art, and consequently it is clear that there is a need in the art for an improvement to existing walk-in bathtub devices. In this regard the instant invention substantially fulfills these needs.
SUMMARY OF THE INVENTION
[0017] In view of the foregoing disadvantages inherent in the known types of walk-in bathtubs now present in the prior art, the present invention provides a new walk-in bathtub assembly that can be utilized for providing convenience for the user when setting a bath before entering the same, and further for using a walk-in bathtub as either a standup shower, a soaking tub, or a bathtub stall with interior seated support.
[0018] It is therefore an object of the present invention to provide a new and improved walk-in bathtub assembly that has all of the advantages of the prior art and none of the disadvantages.
[0019] It is another object of the present invention to provide a walk-in bathtub assembly that is useable as a standup shower, a seated bathtub stall, or a full soaking tub, while at the same time provide an entry door for walking directly into the bathtub interior.
[0020] Another object of the present invention is to provide a walk-in bathtub assembly that includes an interior dam element that allows a user to segment the bathtub into two or more compartments, whereafter the first compartment may be filled prior to the user entering the bathtub or closing the entry door.
[0021] Yet another object of the present invention is to provide a walk-in bathtub assembly that includes a deployable seat from the second compartment, whereby the seat allows users to sit and wash themselves without fully entering the tub or standing.
[0022] Another object of the present invention is to provide a walk-in bathtub assembly that has an entry door that does not require users to lift their legs to enter the bathtub interior.
[0023] A final object of the present invention is to provide a walk-in bathtub assembly that may be readily fabricated from materials that permit relative economy and are commensurate with durability, wherein the assembly is built to the standard of walk-in bathtubs and will not leak when in a working state.
[0024] Other objects, features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0025] Although the characteristic features of this invention will be particularly pointed out in the claims, the invention itself and manner in which it may be made and used may be better understood after a review of the following description, taken in connection with the accompanying drawings wherein like numeral annotations are provided throughout.
[0026] FIG. 1A shows an overhead view of the bathtub assembly of the present invention with the entry door in an open configuration and the first compartment filled with water.
[0027] FIG. 1B shows an overhead view of a second embodiment of the bathtub assembly.
[0028] FIG. 2 shows another overhead view of the bathtub assembly of the present invention in a working state, wherein the deployable seat is in a downward position for use as a seated support within the bathtub interior.
[0029] FIG. 3 shows a view of the outer wall of the walk-in bathtub and the entry door in an open configuration while filling the first compartment with water.
[0030] FIG. 4 shows a view of the walk-in bathtub assembly in use by a seated user.
[0031] FIG. 5 shows a view of the walk-in bathtub assembly in use by a standing user.
[0032] FIG. 6A shows a cross section of the present invention during the initial stages of the bathtub filling, wherein the first compartment is being filled and set prior to user entry.
[0033] FIG. 6B shows a second cross section view after the user has entered the set bathtub and removed the central dam element to fill both compartments.
[0034] FIG. 6C shows a third cross section view of the bathtub being filled after the user has entered the tub, replaced the dam element, and placed the seat into a down position for seated bathing.
[0035] FIG. 6D shows a fourth cross section view of the tub being drained, wherein the dam element separates the first and second drains and allows the user to exit the second compartment even if the first compartment is still draining.
[0036] FIG. 7 shows an overhead perspective view of the tub of the present invention, whereby two dam elements are present to segment the tub into three distinct compartments.
DETAILED DESCRIPTION OF THE INVENTION
[0037] Reference is made herein to the attached drawings. Like reference numerals are used throughout the drawings to depict like or similar elements of the walk-in bathtub assembly. For the purposes of presenting a brief and clear description of the present invention, the preferred embodiment will be discussed as used for providing a new and improved walk-in bathtub for the elderly or disabled. The figures are intended for representative purposes only and should not be considered to be limiting in any respect.
[0038] Referring now to FIG. 1A , there is shown an overhead perspective view of the walk-in bathtub of the present invention in a working state with its first compartment 100 filled with water for bathing, and the entry door 41 in an open configuration. The bathtub comprises an upstanding front wall 40 , a pair of end walls 44 , and a rear wall 49 that surround an open bathtub interior having a base surface. To facilitate entry into the bathtub interior, an entry door 41 is provided along the front wall 40 to allow entry therethrough without lifting one's legs. The door 41 pivots from the front wall 40 by way of a hinge joint 20 , while the edges 42 of the door 41 align with a cutout in the front wall 40 when closed. Between the cutout and the door edges 42 is a seal or gasket 43 that prevents leaking therethrough. To secure the door 41 against the front wall 40 , a handled latch (not shown) is provided to prevent the door 41 from freely swinging open during use.
[0039] Within the bathtub interior is one or more laterally extending dam elements 50 that are adapted to segment the bathtub interior into two or more compartments. As shown in FIGS. 1A through 6 , an embodiment with one dam element 50 is used to segment the tub into a first 100 and second 101 compartment, thereby preventing water communication between the compartments when fully installed. The dam element 50 is an operably installed member that preferably slides into defined slots 51 along the walls of the bathtub interior to lock the dam element 50 into place and secure the same against the walls of the bathtub interior. This element 50 allows users to fill the first compartment 100 of the bathtub interior while the second compartment 101 remains dry and free of water. In use, the user can fill the first compartment 100 with warm or hot water and set the water with soap or any other additives, all without having to secure the entry door 41 closed.
[0040] The ability to set the bath before closing the entry door 41 is a unique ability in the art of walk-in bathtubs, as the user generally has to first enter into the bathtub, seal the entry door, and then start the flow of water. The present invention allows a user to fill the first compartment 100 with warm water and prepare it for use without physically entering the bathtub interior or sealing the entry door 41 closed against the outer wall 40 .
[0041] Referring now to FIGS. 1A , 1 B, and 2 , the deployable seat 45 of the present invention is shown in a stowed configuration and in a deployed state. The deployable seat 45 is a hinged 48 support surface that is mounted to the rear end wall 44 of the bathtub and can pivot between an upright (stowed) position, and a horizontal (working) position. The seat 45 is preferably positioned within the second compartment 101 of the bathtub interior and allows the user to set the water in the first compartment 100 and rest on the seat 45 for washing oneself in a seated position. The user can further fill the first compartment 100 , enter the second compartment 101 while the seat 45 is stowed, closed the entry door 41 , and then deploy the seat 45 for resting on the same.
[0042] The seat 45 is supported along the bathtub interior such that the weight of the user is supported during use. The outer edge of the seat 45 may rest against the upper portion of the dam element 50 , as shown in FIG. 2 , or alternatively the seat 45 may not extend outward to the extent of the dam element 50 position. In this alternative, the user has room to place his or her legs between the dam element 50 and the seat 45 without removing the dam element 50 . If the seat rests against the dam element 50 , the user can step over the dam element 50 , supporting himself along the upper edge 49 of the bathtub sides for support. Thereafter the user can wash himself while seated using water prepared in the first compartment 100 . To assist the user during this motion, hand rails may be provided for the user to grasp along the shower sides (not shown).
[0043] Referring specifically to FIG. 1B , an alternate configuration for the dam element 50 and its attachment to the interior walls of the bathtub includes a hinged configuration. In this embodiment, the dam element 50 is secured across the bathtub interior when deployed and does not let water pass therethrough, while the dam element can be pivoted via a hinge joint 55 from a deployed state to a stowed state against the inner walls of the tub via a hinge joint along one side thereof. The hinge joint 55 allows the dam element 50 to swing into position or out of the way as desired by the user, and is submitted as an alternative to the slots 51 shown in FIG. 1A .
[0044] Referring now to FIG. 3 , there is shown a view of the walk-in bathtub of the present invention being filled in the first compartment 100 while the second compartment 101 remains dry and the entry door 41 can be opened for ease of entry. When entering, the deployable seat 45 is positioned in a stowed state and the user can enter the cutout in the bathtub front wall 40 to enter the bathtub interior without stepping over any obstacles. Once in the bathtub interior, the user can close the entry door 41 and use the shower in a stand-up configuration, in a seated configuration, or the user can lift the dam element to fill the entire interior with bathing water for use as a soaking tub. Also shown in FIG. 3 is the second drain 82 positioned within the second compartment 101 of the bathtub. The bathtub comprises a first 81 and second 82 drain, wherein each is positioned in corresponding compartments for independently draining the same. When the dam element is in position, the first 100 and second 101 compartments drain independently, allowing a user to exit the second compartment 101 if that compartment has drained before the first compartment 100 . This allows for quicker exiting without waiting for the entire tub to drain. Since the second compartment is a smaller volume, it will drain faster.
[0045] Referring now to FIGS. 4 and 5 , there are shown views of the walk-in bathtub of the present invention in a working state, first in a seated state ( FIG. 4 ), and then as a standing shower ( FIG. 5 ). In a seated state, users can rest on the deployed seat 45 and bathe themselves with the water in the first compartment 100 . If the user decides to use the entire tub and to soak therein, the user can stow the seat 45 and remove the dam element 50 to allow water to communicate from the first compartment 100 to the second compartment 101 . It is contemplated that the dam element 50 be secured seated within slots 51 along the sides of the bathtub interior.
[0046] Also shown in FIG. 4 is a view of the first drain 81 positioned within the first compartment 100 . As previously explained, the independent drains allow the bathtub compartments to drain at different rates, allowing a user to exit the second compartment 101 before the entire bathtub has drained to reduce waiting time during this period. It is further contemplated that the dam element may optionally include a drainage plug for allowing water to communicate thereacross. This embodiment allows the user to equalize pressure on both sides of the dam 50 before lifting and removing the same. Yet another embodiment of the present invention is to provide a drain in both bathtub compartments for independent draining therefrom.
[0047] Referring now to the cross section views, FIGS. 6A-6D , there is shown a sequence of views that illustrate filling and setting the bathtub, filling the entire bathtub interior for soaking, and then draining the bathtub using the independent drains. Referring specifically to FIG. 6A , this cross section view illustrates the initial stage of the bathtub filing, wherein the user has installed the dam element 50 between the first 100 and second 101 compartments of the bathtub and is filling the first compartment 100 with a water of desired temperature. The second compartment remains empty for the user to enter the bathtub without spilling any water contents from the first compartment 100 . Once the first compartment 100 has been filled with water of a desired temperature and the user has entered the second compartment 101 , the dam element is removed to fill the entire bathtub interior, as is shown in FIG. 6B .
[0048] Once both compartments 100 , 101 are filled, the water level in the bathtub can be raised to the desired level. If the user desires, the tub can be utilized as a soaking tub, wherein the dam element 50 is replaced and the seat 45 is deployed. The water level can be maintained below the level of the seat 45 or filled to the capacity of the bathtub for complete body soaking, as is shown in FIG. 6C . After the user has finished soaking or bathing, the seat 45 is stowed and the dam element 50 is installed for draining the first 100 and second 101 compartments individually. The first 81 and second 82 drains then drain the compartments independently. To reduce the wait time for the user during the draining phase, the second compartment 101 is sized slightly smaller than the first compartment 100 to allow for swifter draining through the second drain 82 . This allows the user to exit from the second compartment 101 through the entry door before the entire tub is drained, as is shown in FIG. 6D . Therefore, the present invention offers a user a unique method of first setting the bathtub and thereafter draining the same when the user desires to exit the same.
[0049] Referring finally to FIG. 7 , there is shown yet another embodiment of the present invention, whereby the tub is segmented into three compartments by a first and second dam element 50 . In the same manner as the single dam embodiment, the multiple dam embodiment allows a user to further segment a tub into compartments for separate uses, or for preparation prior to entry into the tub. In this embodiment, the drains are disposed within the outermost compartments, while the central compartment can remain filled during draining. Each of the dams is operably placed in a working state, either using the slots 51 , hinge joint, or similar attachment arrangement.
[0050] Overall, the bathtub of the present invention is configured to allow preparation of the bathwater before entry thereinto, while also facilitating use of the tub in several different configurations. The size, shape, and materials of the bathtub may take on several forms, falling within the scope of the functional elements of its use and for providing a sealed, comfortable bathtub for use while standing, seated, or while soaking.
[0051] Senior citizens and those with joint pain, injuries or physical disabilities may struggle to step into a standard bathtub. Existing walk-in bathtubs require the individual to stand or sit inside the tub while it fills, and again as it drains. This process wastes the person's time and can leave the individual feeling cold and uncomfortable. The present invention describes a new walk-in bathtub assembly. The assembly comprises a walk-in bathtub that has one or more dam elements that divide the tub interior into two distinct compartments. A user can fill a first compartment without having to be inside the tub while waiting for the water to fill. Once the water reaches a desired level and temperature, the user can enter a secondary compartment, disrobe and release the dam, which will in turn fill the secondary compartment. The user can alternatively deploy the seat for use of the first compartment water without releasing the dam and without remaining in a standing position. Finally, the user can choose to use the bathtub assembly as a standard shower tub for upright cleaning.
[0052] It is submitted that the instant invention has been shown and described in what is considered to be the most practical and preferred embodiments. It is recognized, however, that departures may be made within the scope of the invention and that obvious modifications will occur to a person skilled in the art. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
[0053] Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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A bathtub is provided of the walk-in type, wherein the bathtub includes an at least one internal dam element that allows a user to segment the bathtub into a two or more compartments and operably utilize the bathtub as a sit-down tub or as a standing shower. An entry door provides access into the bathtub without requiring users to lift their legs during entry, while the dam elements allow the user to fill the sectioned compartments of the tub and prepare it for use before entering the bathtub interior. Certain compartments may remain empty as the other compartments fill with water, whereafter the user can enter the empty the empty compartment and remove a dam element after closing the entry door. The bathtub further may also comprise a first and second drain for independently draining the compartments.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to earthworking apparatus and in particular to cutting bits for installation on the blade portions of such apparatus.
2. Description of the Prior Art
As disclosed in U.S. Pat. No. 2,831,275 of Woodrow P. Kinsey et al, owned by the assignee hereof, it is common to provide cutting bits on the blade portion of earthworking equipment, such as earth-moving scrapers and bulldozers. As disclosed in the Kinsey et al patent, such cutting bits are conventionally arranged to be secured to the outside of the scraper bowl by suitable bolts. Such bits effect a cutting action on the earth as the blade is moved forwardly to insure a clean cut. The use of the bits effectively extends the useful life of the blade by minimizing the erosion and wear of the blade proper so as to minimize expense and time consumption in repairing of the blade as a result of such erosion and wear.
In the Kinsey et al patent, the cutting bits are provided with a second set of cutting edges so that when one edge of the cutting bit becomes worn, the bit may be removed and reversely installed on the opposite wall of the scraper bowl so as to dispose the unused cutting surface forwardly and thereby provide extended useful life of the cutting bits.
In U.S. Pat. No. 3,190,018 of Maclay P. Nelson et al, a reversible bit is disclosed which is mounted on the blade by means entirely rearward of the cutting surfaces of the blade so as to provide protection for the mounting means, such as from impact against soil or rocks engaged by the bit or blade.
SUMMARY OF THE INVENTION
The present invention comprehends an improved form of reversible bit for selective mounting to an earthworking blade, and more specifically, is directed to such a bit for use at the opposite corner portions of the blade.
The invention comprehends the provision of such a reversible end bit defined by a rigid member having a first cutting edge portion, a second cutting edge portion extending transversely to the first cutting edge portion, and a mounting portion included between the cutting edge portions and adapted to be mounted to one corner portion of a blade with the first cutting edge portion in cutting position and to the opposite corner portion of the blade with the second cutting edge portion in cutting position.
More specifically, the rigid member may comprise a triangular member having substantially rectilinear cutting edge portions, with one cutting edge portion extending perpendicular to the other and with the mounting portion of the bit defining a generally triangular mounting portion.
The bit may be made symmetrical about a centerline bisecting the angle defined by the cutting edge portions so that selective rotation of the bit 90° about the apex of the bisecting centerline and triangular mounting portion disposes selectively either of the two cutting edge portions in cutting position when mounted to the opposite corners of the blade.
The cutting edge portions may project forwardly from the flat plane of the mounting portion so as to define mutual strengthening means.
The bit may be mounted to the blade corners by suitable bolts, which, by virtue of the triangular arrangement of the mounting portion may be spaced from the corner tip portions of the blade to provide improved minimum distortion mounting of the bits to the blade.
Thus, the reversible end bit of the present invention is extremely economical of construction while yet providing the highly desirable features discussed above.
BRIEF DESCRIPTION OF THE DRAWING
Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:
FIG. 1 is a fragmentary front elevation of a bulldozer blade having reversible end bits embodying the invention;
FIG. 2 is a view taken along line 2--2 in FIG. 1; and
FIG. 3 is an isometric view of reversible end bits.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the exemplary embodiment of the invention as disclosed in the drawing, an earthworking blade generally designated 10 is shown to comprise a bulldozer blade having opposite end portions 11 and 12, respectively defining corner portions 13 and 14. A conventional elongated bit generally designated 15 may be secured to the mid-portion of the blade by suitable bolts 16.
The present invention is concerned with the provision of improved reversible end bits generally designated 17 amd 18 which, as shown in FIG. 1, are adapted to be mounted to the corner portions 13 and 14 of the blade 10 by suitable bolts 19. Bits 17 and 18 are identical comprising reversible end bits which may be selectively installed on either corner portion 13 or 14. For this purpose, each bit is provided with a first cutting edge portion 20 and a second cutting edge portion 21. As shown in FIG. 1, when the bit is installed on the right-hand corner portion 13, the cutting edge portion 20 is disposed lowermost in cutting position with the cutting edge portion 21 extending upwardly therefrom in a retracted position. When the bit is installed on the lefthand corner portion 14 of the blade, the cutting edge portion 21 is disposed lowermost in the cutting position with the cutting edge portion 20 extending upwardly in a retracted position.
Thus, the end bits may be installed on either end of the bulldozer blade by a simple 90° rotation of the bit.
More specifically, as seen in FIG. 3, each bit is defined by a rigid member having a first cutting edge portion 20 and a second cutting edge portion 21 with a mounting portion 22 included between the cutting edge portions and adapted to be mounted to the blade corner portion, as discussed above. The mounting portion may be provided with a plurality of holes 23 opening forwardly through recess portions 24 for receiving the bolt heads.
The cutting edge portions 20 and 21 may extend forwardly from the flat plane of the mounting portion 22 so as to dispose distal forward cutting edges 20a and 21a, respectively, substantially forwardly of the plane of the mounting portion.
As best seen in FIG. 3, the cutting edges 20a and 21a are inclined to the flat plane of the mounting portion with the maximum spacing thereof forwardly from the plane of the mounting portion being at a juncture 25 of the two cutting edge portions aligned with the apex 26 of the triangular mounting plate 22.
In the illustrated embodiment, the cutting edge portions 20 and 21 are integrally joined at the juncture 25 and are integrally formed with the mounting plate portion 22 to define an integral one-piece bit construction.
The cutting edge portions may define inturned distal ends 27 and 28, respectively, which are turned to extend generally parallel to the other cutting edge portion at the opposite edge of the mounting plate portion 22. As shown, the distal portions 27 and 28 may run into the flat plane of the mounting portion 22.
Each of the cutting edge portions 20 and 21 may comprise generally planar portions along the two sides of the triangular mounting plate 22 extending from the apex 26. The planes of portions 20 and 21 along these edges may be inclined outwardly relative to the mounting plate whereby the bit effectively defines a forwardly widening structure. Thus, the cutting edge portions effectively define reinforcing or strengthening means as well as defining the cutting edges of the bit.
Referring to FIG. 3, the bolt holes 23 may be spaced from the apex 26 to provide an improved mounting of the cutting bits to the blade corner portions 13 and 14. Further, as the triangular arrangement of the mounting plate member provides mounting bolt holes remotely from the lowermost cutting edge, a further improved secure mounting of the end bits to the blade is effected.
In the illustrated embodiment, the end bits are symmetrical about a centerline extending from the apex and bisecting the angle defined by the forwardly projecting cutting portions 20 and 21. Thus, the end bits function identically in their mounting at either end of the cutting blade. Thus, with the triangular arrangement of the present end bits, the mutually interacting support provided by the forwardly projecting cutting edge portions provides a high strength, long life bit construction providing substantial improvement over the bit constructions of the prior art.
Referring to FIG. 2, it may be seen that the extending plates and relieved areas at each end of the blade provide ready access to bolts 19 and facilitate mounting and service of the end bits 17 and 18.
The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.
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A reversible bit for selective mounting to an earth-moving blade, such as a bulldozer blade, having opposite corner portions. The bit includes transversely extending cutting edge portions and a mounting portion adapted to be selectively mounted to opposite corners of the blade with one or the other of the cutting edge portions suitably disposed in cutting position whereby the bit provides substantially twice the normal life of the conventional blade bit.
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This is a continuation of application Ser. No. 396,380, filed Aug. 18, 1989, which is a continuation of U.S. Ser. No. 162,046, filed Feb. 29, 1988, now both abandoned.
FIELD OF THE INVENTION
The present invention relates generally to BF 3 -etherate complexes useful for polymerization of 1-olefin containing feedstocks. More particularly the invention is directed to BF 3 -etherates in which the ether of the BF 3 -etherate has at least one tertiary carbon bonded to an ether oxygen, and to a process for polymerizing feedstocks comprising isobutylene wherein the BF 3 -tertiary etherate is the catalyst. The BF 3 -tertiary etherates of the present invention and the polymerization process employing them are suitable for manufacturing polybutene having a very high percentage (80 to 100%) of vinylidene olefin.
DISCUSSION OF THE PRIOR ART
Generally speaking, polymerization of 1-olefin containing feedstocks using catalysts such as aluminum chloride and boron trifluoride is disclosed extensively in the patent and technical literature. It is well known that the termination step in isobutylene polymerization results in a "terminal" double bond which imparts desired reactivity to the polymer for subsequent reactions, such as epoxidization or reaction with maleic anhydride. However, a problem exists in that the termination step can place the terminal double bond in a highly reactive external 1,1-disubstituted position (hereafter "vinylidene"), or in a much less reactive internal tri-substituted or tetrasubstituted position. These three possible terminal double bond positions are shown below. ##STR1##
Referring to this problem, Samson U.S. Pat. No. 4,605,808 states that the product obtained upon conventional polymerization of isobutylene is generally a mixture of polymers having a high proportion of internal versus external (vinylidene) unsaturation due to "in situ" isomerization of the more highly reactive vinylidene double bond to the less reactive internal positions. The diminished reactivity of the hindered internal tri-substituted or tetra-substituted double bond is most notably observed in the manufacture of the valuable intermediate polyisobutenyl succinic anhydride ("PIBSA") which is obtained by reaction of maleic anhydride with polybutene. PIBSA is a very important intermediate in the manufacture of fuel and lubricant additives. The lowered reactivity of polybutene due to the presence of substantial internal olefinicity reduces the yield of PIBSA when the polymer is reacted with maleic anhydride and thus dictates higher usage of polybutene than would otherwise suffice if the polybutene consisted mainly of vinylidene olefin.
Given the above problem, it has long been an object of research in the area of polybutene manufacture to improve the reactivity of polybutene, particularly its reactivity toward maleic anhydride, by identifying catalysts or catalyst systems capable of polymerizing isobutylene such that the resulting polybutene has the highest possible percentage of vinylidene double bonds.
A number of patents have sought to address this very problem. Nolan U.S. Pat. No. 3,166,546 discloses a vapor phase process for isobutylene polymerization which requires using a mixture of gaseous boron trifluoride and sulfur dioxide under specified conditions. The patent states that sulfur dioxide directs the polymerization reaction such that substantially all of the polybutene has vinylidene unsaturation. In column 1 of the patent, it is stated that the boron trifluoride catalyst requires a small amount of water, alcohol, carboxylic acid, mineral acid or ether to initiate the catalyst. However, there is no suggestion for the use of BF 3 -tertiary etherate complexes. Moreover, the sulfur dioxide process does not appear to be commercially viable.
In later work using BF 3 catalyst, Boerzel et al. U.S. Pat. No. 4,152,499 disclosed that BF 3 mainly favors the formation of polymer having the reactive double bond in the vinylidene position if a short polymerization time (3 to 5 minutes) is strictly maintained.
Most recently, Samson U.S. Pat. No. 4,605,808 discloses isobutylene polymerization using a preformed boron trifluoride/alcohol complex and contact times in the range of 8 to 70 minutes, as a means of obtaining a high percentage (at least 70 percent) of vinylidene content in the resulting polybutene polymer.
While the patents cited above dealing with BF 3 catalysis are indicative of progress toward the achievement of a highly reactive (high vinylidene) polybutene, a number of problems remain to be solved. First, the teachings of these patents place strict restraints on the contact time for the catalysts. For example, in the case of the above cited Boerzel Patent, a contact time of 1 to 10 minutes is claimed but 3 to 5 minutes is the preferred range. If the brief contact times are not maintained, the desired high levels of vinylidene unsaturation cannot be achieved given the tendency of the vinylidene double bonds in the polymer to isomerize in the presence of the catalyst to the less reactive internal type double bond.
To some extent, this problem may have been alleviated in the Samson '808 patent teaching use of a preformed boron trifluoride/alcohol complex with contact times of 8 to 70 minutes to obtain polymer having at least 70% vinylidene content. Nevertheless, it is desired to increase even further the percentage of vinylidene content obtainable in the polymer, while at the same time eliminating or minimizing the dependency of such outcome upon rigorously maintained contact times.
Inasmuch as the present invention relates generally to isobutylene polymerization in the presence of boron trifluoride etherate complexes, a number of additional literature references and patents, in addition to those already discussed above, are believed to be of general relevance although they fail to address the problem sought to be overcome by the present invention and can be readily distinguished. For example, Dornte U.S. Pat. No. 2,559,062 discloses isobutylene polymerization using boron trifluoride complexed with di-n-butyl ether, halogen-substituted dialkyl ethers, aryl-alkyl mixed ethers, nitroaryl ethers, cyclic ethers and unsaturated ethers. The patent notes that the types of ethers used for complexation with BF 3 may not be indiscriminately selected, and makes no mention of tertiary etherates in which a tertiary carbon is bonded to the ether oxygen.
Stevens et al. U.S. Pat. Nos. 2,588,425 and 2,591,384 disclose preparation of an isobutylene polymer consisting almost exclusively of tetraisobutylene or triisobutylene. The tetramer or trimer is prepared from isobutylene at 0° C. to 55° C. in the presence of a boron trifluoride ether complex. The ether compounds disclosed by Stevens do not include tertiary ethers.
Montgomery et al. U.S. Pat. No. 2,559,984 teach the use of aluminum chloride or boron fluoride catalysts complexed with organic compounds, but the patent mentions ethers only in the context of aluminum chloride catalysts.
Ikida U.S. Pat. No. 2,777,890 discloses the use of a boron trifluoride diethylether complex as a catalyst for polymerization of butadiene-1,3.
Throckmorton U.S. Pat. No. 3,962,375 discloses boron trifluoride complexed with ethers of the formula ROR' where R and R' represent alkyl, cycloalkyl, aryl, alkyaryl, arylalkyl radicals containing from 1 to about 30 carbons.
Serniuk U.S. Pat. No. 2,780,664 discloses preparation of a drying oil by contacting a mixture of 75 parts by weight of butadiene and 25 parts by weight of isobutylene in the presence of boron trifluoride ethylether complex.
Geiser U.S. Pat. No. 3,006,906 discloses copolymerization of isobutylene with a tetra-substituted alkylene diamine in the presence of a boron trifluoride ethylether complex.
Holmes U.S. Pat. No. 2,384,916 discloses a method of producing high molecular weight iso-olefin polymers using boron trifluoride catalysts promoted with ethylether, normal propylether, isopropylether, normal butylether, methyl normal butylether and isomaylether. The use of boron trifluoride:tertiary ether complexes to obtain polybutene having high levels of vinylidene unsaturation is no where disclosed or suggested in this patent.
Finally, it should be noted that early work by Evans et al. determined the necessity in BF 3 catalysis of a complexing agent able to donate a proton. Evans discovered that no polymerization will occur when pure diisobutylene is exposed to BF 3 unless a trace amount of moisture is present. This finding has generally led to the acceptance of a cationic mechanism, and therefore the requirement of a proton source, for both BF 3 and AlCl 3 catalysis. The early work of Evans in conjunction with his associates, Meadows and Polanyi, is described in Nature (1947) 160, page 869; J. Chem. Soc. (1947) 252; and Nature (1946) 158, page 94. To date, the cationic mechanism ascribed to BF 3 and AlCl 3 catalysis requiring proton donation to initiate polymerization is widely accepted.
To the best of my knowledge the patents and literature references discussed above with respect to the use of BF 3 -etherate complexes are not addressed to the attainment of high vinylidene content in polybutene and do not teach tertiary etherates capable of achieving that result. On the contrary the BF 3 ether complexes taught in these early patents are inactive unless they are activated with a proton source. Under the accepted cationic mechanism for such polymerization the actual BF 3 catalyst in the presence of such a proton source acts as a Lewis acid having a strong tendency to isomerize the vinylidene double bonds to the less reactive internal double bonds and to cause skeletal rearrangements and branching of the polybutene formed during the polymerization reaction. The latter is a disadvantage in that a highly linear polymer is generally preferred in lubricant additive manufacture.
In view of the foregoing discussion of the prior art, an object of the present invention is generally to provide an improved BF 3 catalyst system useful in the preparation of polybutene having a high percentage of vinylidene unsaturation. Other objects will be apparent hereinafter to those skilled in the art.
SUMMARY OF THE INVENTION
I have now discovered an improved boron trifluoride catalyst system for use in the polymerization of 1-olefin containing feedstocks. The catalyst system comprises a BF 3 -etherate complex in which the ether has at least one tertiary carbon bonded to an ether oxygen. The tertiary ether can have the general formula: ##STR2## where R 1 is C 1 to C 20 hydrocarbyl or halo-substituted hydrocarbyl and R 2 R 3 and R 4 , the same or different, are selected from the group consisting of (1)--CH 2 R' where R' is H, halogen, or C 1 to C 20 hydrocarbyl or halo substituted hydrocarbyl; (2)--CH═R" where R" is C 1 to C 20 hydrocarbyl or halo substituted hydrocarbyl; and (3)--C.tbd.R"' where R"' is C 1 to C 20 hydrocarbyl or halo substituted hydrocarbyl. Preferred tertiary ethers for use in preparation of the BF 3 -etherate complexes of the present invention are those in which R 2 , R 3 and R 4 in the above formula are methyl, and R 1 is C 1 to C 10 hydrocarbyl. Particularly preferred are the alkyl tert-butyl ethers, e.g., methyl t-butyl ether, n-butyl t-butyl ether, isopropyl t-butyl ether, di-tert-butyl ether, ethyl tert-butyl ether, pentyl tert-butyl-ether, 1,1'-dimethylbutyl methylether, etc.
As a method, the present invention is directed to a process for polymerizing a feedstock comprising 1-olefin which process comprises the step of contacting the feedstock with a BF 3 -tertiary etherate as described above at -100° to +50° C. The process is suitable for polymerizing isobutylene to obtain commercial grade polybutene having high percentages of vinylidene olefinicity (i.e., 80 to 100%).
A principle advantage of the BF 3 -tertiary etherate complexes of the present invention is their ability to produce polybutene polymer having higher percentages of vinylidene unsaturation (80 to 100%) than obtained using the BF 3 -catalysts of the prior art (i.e., Boerzel U.S. Pat. No. 4,152,499 and Samson U.S. Pat. No. 4,605,808) which, by comparison, are taught to be capable of producing vinylidene contents in the range of only about 60 to 90%.
The etherates of the present invention also compare favorably to the BF 3 -alcoholate complexes of Samson in their ability to produce higher molecular weight polymer at a given temperature.
Still a further advantage is that longer residence times are acceptable in the BF 3 -etherate catalyzed polymerization of the present invention. Residence times of 10 minutes to 3 hours (or greater) can be used depending upon temperature, catalyst concentration and desired molecular weight.
Further advantages include the fact that the BF 3 -etherates of the present invention are more active than BF 3 -alcohol complexes and show greater selectivity for isobutylene than conventional AlCl 3 catalyst. This latter advantage reduces the stripping required for the raw polybutene product.
Finally, in comparison to aluminum chloride catalyzed polymerization, the polybutene product resulting from the BF 3 -tertiary etherates of the present invention is more linear (less branching and skeletal rearrangements) and is consistently colorless.
Surprisingly, unlike the prior art BF 3 catalyst systems which require a protic source (i.e., water, alcohol, mineral acid, etc.) to initiate polymerization, the BF 3 -tertiary etherate complexes of the present invention do not require protic initiation. In fact, they are found to perform optimally in terms of high vinylidene content, using feeds that are essentially completely free of water or other protic species capable of complexing with the BF 3 by displacement of the tertiary ether. As the presence of water or other proton donating species in the feed or reaction zone increases, even slightly, the ability of the BF 3 -tertiary etherates to produce high vinylidene falls off dramatically. Therefore the preferred feedstock for use in the present invention should be as anhydrous as possible, preferably containing no greater than about 1 to about 10 ppm water. However feeds having 10 to 20 ppm H 2 O can be used without seriously impairing the advantages of the present invention. At levels greater than about 20 ppm H 2 O, the BF 3 etherates of the present invention may perform worse than the prior art BF 3 catalysts measured in terms of the ability to produce high vinylidene content in the polymer product.
Without any intention to be bound to a particular theory, it is believed that the advantages noted above, namely higher vinylidene content, longer residence times, higher molecular weight polymer, more linear polymer, etc., result from the fact that the BF 3 tertiary etherates of the present invention do not require protic initiation for polymerization to take place. Protic initiation, characteristic of a cationic mechanism for isobutylene polymerization results in a reaction environment which is highly acidic due to the proton donation by the active catalyst species, such active species being a complex of the protonic entity (for example water) and the BF 3 . The acidic reaction environment characteristic of proton initiated polymerization is believed the principle cause underlying isomerization of terminal vinylidene unsaturation to the less desired and less reactive internal unsaturation. Acidity at the onset of polymerization resulting from proton donation of the catalyst species also causes skeletal rearrangements and fragmentation of the forming polybutene polymer. By comparison, in view of the evidence that the BF 3 tertiary etherate complexes of the present invention are capable of operating in an essentially completely anhydrous environment requiring no protic initiation, polymerization in accordance with the present invention is initiated in a substantially nonacidic environment which reduces acid catalyzed isomerization of vinylidene double bonds to di-, tri- and tetra-substituted internal double bonds. Also, fragmentation and skeletal rearrangements are minimized. As distinguished from a cationic mechanism, it is believed that polymerization in the present invention proceeds via a covalent mechanism.
A critical feature of the present invention which dictates the ability of the BF 3 -etherates disclosed herein to produce high vinylidene polymer and to operate without necessity of protic initiation, is that the ether in the BF 3 -etherate complexes must have at least one tertiary carbon bonded to the ether oxygen. BF 3 -etherates which do not fulfill this requirement are outside the scope of the present invention and will not polymerize isobutylene in such a manner as to produce the very high levels of vinylidene possible in the present invention.
DETAILED DESCRIPTION
The BF 3 -tertiary etherates of the present invention can be prepared by reacting gaseous BF 3 with a tertiary ether under carefully controlled conditions of temperature and rate of reaction whereby the exothermicity of the BF 3 -etherate complex formation is prevented from causing the decomposition of the complex. In the case of the BF 3 -methyl t-butyl ether or n-butyl t-butyl ether complexes, such decomposition would result in the formation of BF 3 methanol (or butanol) complexes with the release of isobutylene and dimers or trimers of isobutylene. To prevent such decomposition, gaseous BF 3 can be bubbled into the ether at a relatively slow rate over a period of about 1 to 5 hours and at a temperature not exceeding about 0° C. A preferred temperature to minimize breakdown of the etherate complex is about -60° to about -30° C. If desired, a further means of controlling the reaction between the BF 3 and the ether is to dilute the BF 3 with an inert gas such as nitrogen and/or dilute the ether with inert solvents such as dichloromethane.
Ether having a tertiary carbon bonded to the ether oxygen can be used in the preparation of the BF 3 -etherates of the present invention. Suitable ethers include methyl tertiary-butyl ether, ethyl tertiary-butyl ether, n-propyl tertiary-butyl ether, isopropyl tertiary-butyl ether, ditertiary-butyl ether, 1,1'-dimethylbutyl methyl ether, and so on. The tertiary position of the ether is preferably a tertiary butyl group for smoothest initiation of polymerization and minimization of branching or skeletal rearrangement in isobutylene polymerization. Also, generally speaking, as the hydrocarbyl group (preferably alkyl) of the non-tertiary portion of the ether is increased from methyl to isopropyl to butyl, etc., the molecular weight of the resultant polybutene polymer is increased.
The mole ratio of ether to BF 3 in the etherates of the present invention should be in the range of about 0.5 to about 3:1. Preferably, to maximize attainment of high vinylidene content in the resulting polybutene polymer, the ether should be in at least a slight molar excess of the BF 3 , most preferably in the range of about 1:1 to about 1.1:1. At mole ratios below about 1:1, the vinylidene content begins to decrease. Above about 1.1:1 little further improvement is observed.
The BF 3 -etherates can be prepared ahead of time for subsequent use as a preformed catalyst complex, such as when polymerization is to be carried out in a batch process. In a continuous process the BF 3 -etherates can be preformed in line immediately prior to entering the polymerization reaction. If performed ahead of time and stored for subsequent use, the BF 3 etherates should be maintained at 0° C. or less to prevent decomposition.
The present invention is also directed to a process for polymerizing a feedstock comprising 1-olefins which process comprises contacting the feedstock with the BF 3 -tertiary etherates described above.
The hydrocarbon feedstock may be pure 1-olefin or a mixture of 1-olefins. 1-olefin feedstock where the olefin contains 3 to 16 carbon atoms is preferred. If a pure olefin is used which is gaseous under ambient conditions it is necessary either to control the reaction pressure or to dissolve the olefin in a solvent medium inert under the reaction conditions in order to maintain the olefin in the liquid phase. In the case of isobutylene, which is typical of 1-olefins, the feedstock used in the polymerization process may be pure isobutylene or a mixed C 4 hydrocarbon feedstock such as that resulting from the thermal or catalytic cracking operation conventionally known as a butadiene or C 4 raffinate. This is a liquid when under pressure and hence no diluent is needed. The feedstock used may suitably contain between 5 and 100% by weight of isobutylene. It is preferred to use a feedstock containing at least about 10% by weight of isobutylene. The hydrocarbon feedstock used may contain, in addition to isobutylene, butanes and butenes without adverse effect on the polybutene product.
The polymerization temperature should be selected based on the molecular weight desired in the product. As is well known, lower temperatures can be used for higher molecular weights while higher temperatures can be used to obtain lighter products. The polymerization of the present invention can be carried out in the full range of temperatures generally associated with conventional polybutene polymerization, i.e., about -100° C. to about +50° C. Polybutene molecular weights in the greatest commercial demand, i.e., those of molecular weight 100 to about 5000 can be obtained in the polymerization of the present invention at temperatures in the range of about -50° C. to about +10° C.
The residence time required in the polymerization of the present invention represents an important advantage over the prior art which generally teaches short, strictly controlled residence times. For example, in Boerzel U.S. Pat. No. 4,152,499, it is shown that residence times exceeding about 10 minutes are detrimental to the vinylidene character of the polymer. By comparison, typical residence times in the present invention range from about 10 minutes to 3 hours, while residence times of greater than 3 hours can be used to produce heavy polymer in reactions carried out at very low temperatures (i.e., -30° to -100° C.). Such longer residence times are possible without the adverse effects upon vinylidene content noted in column 1 of the Boerzel '499 patent. Generally speaking, while the choice of residence time will be dictated in a known manner by factors such as the isobutylene concentration in the feed, temperature of reaction, catalyst concentration and the desired molecular weight of the product, it should be pointed out that the residence time should not be allowed to extend longer than the time required for the isobutylene concentration in the feed to decrease to about 1 wt % (which can be readily monitored by gas chromatography). If allowed to continue beyond this point, the polymer is susceptible to isomerization of the desired vinylidene double bond to the less reactive trior tetra-substituted internal double bond.
The amount of BF 3 -etherate used in the polymerization is not critical to the invention. Generally speaking, amounts ranging from at least about 0.01 mole percent based on isobutylene in the feed are suitable. About 0.05 to about 1 mole % is sufficient to obtain conversions of isobutylene of 80-90%. Generally speaking, raffinate feeds may require higher levels of the BF 3 complex than would suffice for a feed of pure isobutylene, to obtain 80-90% conversions. This is believed due to the number of competing reactions in the raffinate as opposed to synthetic feeds.
The polymerization of the present invention aided by the novel BF 3 -tertiary etherates disclosed herein can be used to obtain a full range of polybutene molecular weights depending upon conditions of reaction time, feed, reaction temperature, etc. all of which can be controlled in a known manner. Polybutene obtained from the present invention having 80 to 100% vinylidene is more reactive than conventional polybutene having much lower vinylidene. As such the polybutene prepared in the present invention is particularly well suited for reaction with maleic anhydride to obtain valuable PIBSA intermediates useful in the manufacture of fuels and lubricant additives.
The following examples are intended for illustration only and should not be construed as limiting the invention set forth in the claims.
EXAMPLE I
Preparation of BF3-Methyl-t-butyl Etherate
Into a 150 ml flask was charged 33 ml (0.28 moles) of methyl-t-butyl ether (MTBE). The flask of ether was then cooled to -40° C. Gaseous BF 3 (6610 cc; 0.28 moles) was then slowly bubbled into the ether at a rate of 22 cc/min. with vigorous stirring. The gas phase of the flask was continually purged with nitrogen and the vent gases bubbled through 20% NaOH to remove acidic components. After addition of the BF 3 was complete, the gas phase of the flask was purged for another 20 minutes to ensure removal of free BF 3 . The BF 3 -methyl t-butyl etherate was stored at 0° C. until ready for use.
EXAMPLE II
Example I was repeated except that ethyl-t-butyl ether was used instead of MTBE.
EXAMPLE III
Example I was repeated using n-butyl-t-butyl ether.
EXAMPLE IV
Example I was repeated using isopropyl-t-butyl ether.
EXAMPLE V
Example I was repeated using di-t-butyl ether.
EXAMPLE VI
Example I was repeated using n-propyl-t-butyl ether.
EXAMPLE VII
Example I was repeated using isoamyl-t-butyl ether.
EXAMPLE VIII
Example I was repeated using 1,1'-dimethylbutylmethyl ether.
EXAMPLE IX
Example I was repeated using cyclohexyl-t-butyl ether.
EXAMPLE X
Example I was repeated using benzyl-t-butyl ether.
EXAMPLE XI
The BF 3 -MTBE complex of Example I was used to polymerize a feed consisting of 20% isobutylene in isobutane. The feed contained less than 1.0 ppm water. Three separate batch polymerizations (summarized in Table 1 below) were run in an autoclave batch reactor equipped with a heat exchanger and in line cooling coils. The autoclave was cooled to the desired temperature followed by addition of 550 grams of the feed. The BF 3 -MTBE complex was charged to a pre-cooled stainless steel bomb attached to the reactor inlet. The complex was introduced into the reactor by purging the bomb with 50 grams of the abovementioned feed, followed by nitrogen to obtain a pressure in the reactor of 200 psi. The reaction conditions for each run are summarized in the Table 1 below. Each run produced colorless polybutene having at least 80% vinylidene content. Product olefin distribution (i.e., relative amount of vinylidene, tri-substituted and tetra-substituted double bond) was determined by 13 C NMR.
TABLE 1______________________________________Isobutylene Polymerization Using BF3-MTBEReaction Mole % of % IsobutyleneTemp (°C.) Catalyst* Conversion Mn Mw______________________________________0 0.05 92 283 4410 0.10 98 279 40910 0.29 88 240 303______________________________________Dispersion .sup.13 C NMR AnalysisIndex % Vinylidene % Tri % Tetra______________________________________1.56 80 17 31.59 81 16 31.26 81 16 3______________________________________ *mole % of catalyst relative to isobutylene.
EXAMPLE XII
In a pilot plant continuous reactor cooled to -15° C., BF 3 -MTBE was preformed by in-line mixing of BF 3 and methyl-t-butyl ether just prior to entering the reactor. The mole ratio of ether to BF 3 was 1:1. The feed was a typical refinery C 4 raffinate (water washed and dried) containing 18% isobutylene and 5 ppm water. The catalyst load was 0.36 mole percent in relation to the washed feed. The colorless product (total polymer) had an olefin distribution of 74% vinylidene, 13% trisubstituted and 8% tetrasubstituted. The stripped polymer had 87% vinylidene, M n =626, M w =789, dispersion index=1.29 and a flash point (ASTM D-92 COC) of 242° C.
EXAMPLE XIII
The batch polymerization process outlined in Example XI was repeated except that BF 3 -butyl-t-butyl etherate (Example II) was used instead of BF 3 -MTBE. Table 2 below summarizes the reaction conditions and results for two separate runs. As in Example XI, the feed was 20% isobutylene in isobutane and virtually anhydrous (<1 ppm H 2 O). Both runs were conducted at -18° C. with a residence time of 60 minutes. The mole ratio of ether to BF 3 in the catalyst complex was 1.1:1.
TABLE 2______________________________________Isobutylene Polymerization Using BF3-BTBEInit. Conc.* GPC Dataof BTBE-BF3 Mn Mw DI______________________________________0.13 1228 2631 2.140.13 1419 2756 1.94______________________________________ *The concentration of BTBEBF.sub.3 in mole % relative to isobutylene.
Olefin Distribution13C NMR% Vinylidene % Trisubstituted % Tetrasubstituted______________________________________87 8 593 7 0______________________________________
EXAMPLE XIV
The batch polymerization of Example XI was repeated except that BF 3 -butyl-t-ether (BF 3 -BTBE) was substituted for BF 3 -MTBE, and a water washed (and dried) refinery C 4 raffinate was substituted for the 20% isobutylene in isobutane feed. Table 4 below summarizes the results of four separate runs. Each run was carried out at -18° C. with a residence time of 40 minutes. Raffinate source "A" (Whiting) consisted of about 14% isobutylene and was dried to <5 ppm H 2 O. Raffinate source "B" (Texas City) consisted of about 18% isobutylene and was dried to a moisture content of <5 ppm H 2 O. The mole ratio of butyl-t-butyl ether to BF 3 in the complex was 1.1:1.
TABLE 3______________________________________Isobutylene Polymerization UsingBF3:BTBE and C4 RaffinateRaffinate Mol % GPC DataSource Catalyst Mn Mw DI______________________________________A 0.76 902 1534 1.70A 1.01 916 1446 1.77B 0.52 806 1842 2.29B 0.78 569 1044 1.83______________________________________Olefin Distribution13C NMR% Vinylidene % Trisubstituted % Tetrasubstituted______________________________________84 12 480 17 381 14 580 15 5______________________________________
EXAMPLE XV
Using the batch polymerization outlined in Example XI, with BF 3 -BTBE catalyst, the effect on vinylidene content of varying the mole ratio of BTBE to BF 3 was studied in five separate runs summarized in Table 4 below. The feed was 20% isobutylene in isobutane (<1 ppm H 2 O), the reaction temperature was -18° C. and the residence time was 40 minutes.
TABLE 4______________________________________Effect of Varying Mole Ratioof Ether to BF3 UponVinylidene ContentMole Ratio Mol. % Olefin Dist. .sup.13 C NMRBTBE/BF3 BTBE:BF3 Vinylidene Tri Tetra______________________________________ 1:1 0.38 76 15 91.1:1 0.52 83 17 0 1:1 0.38 75 18 80.8:1 0.52 63 30 71.1:1 0.62 83 15 2______________________________________
TABLE XVI
The batch polymerization of Example XI was repeated except that the BF 3 etherate was prepared from isopropyl-t-butyl ether (PTBE). The feed was 20% isobutylene in isobutene containing less than 1 ppm H 2 O. Five runs were carried out using a reaction temperature of 0° C. and a residence time of 50 minutes. The runs are summarized in Table 5 below.
TABLE 5______________________________________Isobutylene Polymerization Using BF3:PTBEMole Ratio Mol % GPC AnalysisPTBE:BF3 Catalyst Mn Mw DI______________________________________1.1:1 0.56 323 478 1.48 1:1 1.56 381 583 1.531.1:1 0.42 403 613 1.521.1:1 0.56 487 746 1.53 1:1 0.22 713 1272 1.78______________________________________Olefin Distribution13C NMR% Vinylidene % Trisubstituted % Tetrasubstituted______________________________________100 1 -- 85 13 2100 -- --100 -- -- 85 11 4______________________________________
EXAMPLE XVII
For purposes of comparison, BF 3 -ethanol and BF 3 -butanol complexes were evaluated for their ability to produce polybutene having high vinylidene content. BF 3 -ethanol and BF 3 -butanol complexes were prepared using the general procedures of Example I as follows: Into a flask was charged 1.09 moles of ethanol or butanol. The flask was then cooled to 0° C. with an ice bath. Gaseous BF 3 (1.09 moles) was bubbled into the flask with vigorous stirring over a period of about 120 minutes. The gas phase of the reaction vessel was continually purged with nitrogen and the vent gases bubbled through 20% NaOH to remove acidic components. Following addition of all the BF 3 the gas phase of the flask was purged with nitrogen for another 20 minutes to ensure removal of any free BF 3 . The resulting BF 3 ethanol or butanol complexes were evaluated in a series of runs for polymerization of a feed consisting of 20% isobutylene in isobutane. In Table 6, below, the concentration of the BF 3 -alcohol complex was 0.19 mole % based on the feed, the reaction temperatures were varied (9° C-1° C. and -10° C.) and the residence times were as long as necessary to react about 99% of the isobutylene, which in all of the runs was about 20 minutes. The batch polymerizations were carried out according to the procedures outlined in Example XI. Table 6 below summarizes the results of 3 BF 3 -ethanol runs.
TABLE 6______________________________________Isobutylene PolymerizationUsing BF3-Ethanol ComplexReaction GPC DataTemp. °C. Mw Mn______________________________________ 9 500 300 -1 600 400-10 1000 600______________________________________Olefin Distribution13C NMR% Vinylidene % Trisubstituted % Tetrasubstituted______________________________________76 22 273 24 380 17 3______________________________________
A BF 3 -butanol complex as prepared above was evaluated in four batch polymerization runs using 20% isobutylene in isobutane as the feed. The catalyst concentration was 0.18 mole %, residence times (allowing for reaction of 99% of the isobutylene in the feed) were 30 minutes and the reaction temperatures were -18° C., -12° C., 0° and 10° C. Table 7 below summarizes these four BF 3 -butanol runs.
TABLE 7______________________________________Isobutylene Polymerization UsingBF3-Butanol ComplexReaction GPC DataTemp. °C. Mw Mn______________________________________-18 1700 800-12 1400 700 0 800 400.sup. 10° 450 300______________________________________Olefin Distribution13C NMR% Vinylidene % Trisubstituted % Tetrasubstituted______________________________________75 18 772 21 772 22 672 23 5______________________________________
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Disclosed herein are boron trifluoride etherate complexes in which the ether of the complex has at least one tertiary carbon bonded to an ether oxygen. The etherates are useful for polymerizing a one-olefin or mixtures thereof, preferably comprising isobutylene, whereby the resulting polymer contains a high percentage (80-100%) vinylidene character.
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This application is a national phase of International Application No. PCT/CH2013/000054 filed Mar. 27, 2013 and published in the English language, which claims priority to Application No. GB 1205693.3 filed Mar. 30, 2012 and application No. GB 1209118.7 filed May 22, 2012.
FIELD OF THE INVENTION
The present invention relates to a system and a method of reproducing sound waves.
BACKGROUND OF THE INVENTION
It is known, particularly in certain areas of acoustics and seismics, to interpret pressure and particle velocity measurements as representative of Green's functions or equivalent functions representing the influence that the medium supporting the wave propagation has on a traveling wave or wavefield. Examples of the methods applied in this field can be found for example in:
A. J. Berkhout, D. de Vries, and P. Vogel, 1993, Acoustic control by wave field synthesis: J. Acoust. Soc. Am. 93 (5), 2764-2778; A. J. Berkhout, D. de Vries, and J. J. Sonke, 1997, Array technology for acoustic wave field analysis in enclosures: J. Acoust. Soc. Am. 102 (5), 2757-2770; Cassereau, D., and M. Fink, 1993, Focusing with plane time-reversal mirrors: An efficient alternative to closed cavities: J. Acoust. Soc. Am., 94, 2373-2386; Grote, M., and C. Kirsch, 2007, Nonreflecting Boundary Conditions for Time Dependent Multiple Scattering, J. Comp. Physics, 221, 41-62; Grote, M., and I. Sim, 2011, Local Nonreflecting Boundary Conditions for Time Dependent Multiple Scattering, J. Comp. Phys. 230, 3135-3154; Lim, H., S. V. Utyuzhnikov, Y. W. Lam, A. Turan, M. R. Avis, V. S. Ryanebkii, and T. S. Tsynkov, 2009, Experimental validation of the active noise control methodology based on difference potentials: AIAA Journal, 47, 874-884; van Manen, D. J., Robertsson, J. O. A., and Curtis, A., 2007, Exact wave field simulation for finite-volume scattering problems: J. Acoust. Soc. Am., 122, EL115-EL121; van Manen, Robertsson, Curtis, 2010, Method of evaluating the interaction between a wavefield and a solid body, U.S. Pat. No. 7,715,985B2; Thomson, C. J., 2012, Research Note: Internal/external seismic source wavefield separation and cancellation: Geophysical Prospecting, DOI: 10.1111/j.1365-2478.2011.01043.x; Utyuzhnikov, S. V., 2010, Non-stationary problem of active sound control in bounded domains: J. Comp. Appl. Math., 234, 1725-1731; and Ffowcs Williams, J. E., 1984, Anti-sound: Proceeding of the Royal Society of London A, 395, 63-88. van Manen et al. (2007, 2010) introduced so-called exact boundary conditions (EBC's). These allow for two wave propagation states in a numerical simulation to be coupled together. In particular van Manen et al. (2007) studied the problem of recomputing synthetic seismic data on a model after making local model alterations. EBC's enable to completely account for all long-range interactions while limiting the recomputation to a small model just around the region of change. van Manen et al. (2007) outlined the basic theory and demonstrated it on a ID example. Related concepts were recently proposed by Grote and Kirsch (2007), Grote and Sim (2011), Thomson (2012) and Utyuzhnikov (2010).
The concept of noise cancellation is widely known in the field of acoustic signal processing as described for example by Ffowcs Williams (1984) and Lim et al. (2009). In active noise cancellation a wave signal is recorded using an acoustic transducer (microphone), processed to generate a phase-inverted signal, and emitted by transducers (loudspeakers) to interfere destructively such that the listener no longer hears the original noise.
It is seen as an object of the invention to create a virtual sound environment for a listener such that the listener perceives to be located—at least acoustically—in an environment different from the actual one.
SUMMARY OF THE INVENTION
According to an aspect of the present invention, there is provided a method of and a system for generating an acoustic wave representing reverberations from a desired acoustic environment, said method including the steps of having a recording surface defined by a spatial distribution of recording transducers and an emitting surface defined by a spatial distribution of emitting transducers, wherein the emitting surface defines a volume within which the recording surface is located, recording an acoustic wave originating from within a volume defined by the recording surface using the recording transducers, extrapolating the recorded wave to the emitting surface using a wavefield propagator representing the desired acoustic environment and emitting the extrapolated wave from the emitting transducers.
Reverberations include acoustic wave signals caused by the reflection of an original wave at an acoustic obstacle. Examples of reverberations are echoes. Reverberations can be regarded as the acoustic signature of the environment the listener wishes to be located in. The direct sound of an acoustic event reaching the ear of a listener without reflection is treated as being identical in any environment.
The term “wavefield propagator” is used to denote any wave extrapolation method which includes a signature characteristic of the acoustic medium through which the wave emanating from an original event travels or is supposed to have traveled.
The propagators can be determined through measurements using known test wave signals or generated synthetically provided that sufficient information of the desired acoustic environment is known. Measured propagators can also be augmented by synthetical ones and vice versa.
The receiving surface is best designed to be at least as acoustically transparent as possible, such as using wire frame constructions. However regarding the emitting surface fewer limitations exists. If both are designed to be acoustically transparent, the surfaces are best surrounded by another sound-absorbing surface to further suppress unwanted reverberations of the original acoustic wave from the actual environment of the listener. In another embodiment, the emitting surface coincides with a surface of known acoustic properties such as the reflection coefficient. Such a surface can include pressure-release essentially perfectly reflecting surface, or an essentially perfectly rigid surface. In case the reflection coefficient R is known the emitted wavefield has to include a factor derived from R (using the known laws of reflection to match the amplitudes of the direct wavefield and reverberation to be suppressed.
A spatial distribution of transducers can includes a line of transducer as long as the line is not located in a single flat plane but follows at least partially the contours of the volume.
For most application it can be required to measure not only the amplitude but also directional properties of the wavefield at the recording surface. Hence, in a preferred embodiment of the invention the recording surface includes monopole and dipole transducers and/or at least two spatially separated layers of monopole transducers. Similar arrangements of transducers can be used on the emitting surface to give the emitted wavefield a desired directionality.
For a better cancellation of the direct wavefield it can be advantageous to use wavefield separation filters to the data recorded on the recording surface before extrapolating the filtered data to the emitting surface and/or to extrapolated data before emitting the filtered data along the emitting surface.
The position of a listener is typically within the volume or space as defined by the recording surface. In certain applications such as the shielding of a volume from probing acoustic signals such as sonar waves, the listener can also be envisaged being located outside the emitting surface. In the latter case the role of the emitting and recording surfaces is reversed.
These and further aspects of the invention will be apparent from the following detailed description and drawings as listed below.
BRIEF DESCRIPTION OF THE FIGURES
Exemplary embodiments of the invention will now be described, with reference to the accompanying drawing, in which:
FIG. 1A shows a simplified three-dimensional example in accordance with the present invention;
FIG. 1B shows a cross-section through the surfaces shown in FIG. 1A indicating actual and virtual wave propagation;
FIG. 2 illustrates a method of generating the wave propagator in accordance with an example of the invention; and
FIG. 3 is a flow chart with steps in accordance with an example of the invention.
DETAILED DESCRIPTION
van Manen et al. (2007) showed that in computer simulations the elastodynamic representation theorem can be used to generate so-called exact boundary conditions connecting two states to each other. van Manen et al. (2007) noted that even though the Green's functions inside the boundary (state 1) might be completely different compared to the Green's functions in another greater model (state 2), the two states can be “stitched together” so that Green's functions outside the boundary correspond to state 2 whereas the Green's functions inside the boundary corresponds to state 1. van Manen et al. (2007) exploited this property to be able to regenerate Green's functions after local model alterations on a large computational model while only carrying out computations locally enabling substantial computational savings in computer simulations of wave propagation.
Herein, it is noted that the same equations can be used in a physical set-up to create a virtual acoustic world. Although the following description uses acoustic wave propagation (e.g., sound waves in water or air) as an example, the same methodology applies in principle to elastic waves in solids or electromagnetic wave propagation (e.g., light or microwaves).
In the present example of the invention it is the aim to create a room where an arbitrary acoustic environment can be emulated (in the following referred to as the “sound cave” or the virtual state), as illustrated in FIGS. 1A and 1B . The figures show a possible implementation of the sound cave 10 . The sound cave includes a first inner surface 11 in form of a cube. The inner surface is surrounded by an outer surface 12 also in a cubical shape. As shown in the vertical cross-section of FIG. 1B the surfaces carry receivers (x) and emitters (o). The floor is a shared surface between the two surfaces. A sound event 13 inside the receiving surface 11 creates a sound wave 14 which is registered by a listener 15 .
The method described below includes a step of recording Green's functions WP as wave propagators in a desired acoustic environment (referred to as the desired state; e.g., an alpine meadow surrounded by mountains as indicated in FIG. 2 ., with other examples of a desired environment being an opera house such as La Scala theatre or a church building as St. Paul's Cathedral) with each environment requiring its own recording of the wave propagator or a synthetically generated wave propagator.
The Green's functions WP or any equivalent representation of the desired wave propagator are stored in a computer 18 (see FIG. 1B and FIG. 2 ). A person located in the sound cave will experience an acoustic space corresponding to the Green's functions from the desired state used to generate boundary conditions. The person will be able to interact with “virtual objects” only captured in the Green's functions. For example, if a mountain chain was present at some distance from the location where Green's functions were recorded (as in FIG. 2 ), any sound from within the sound cave, for example a person calling out, will generate echoes from the mountain chain just as if it was actually present.
Green's functions between all points on the emitting and recording surfaces where transducers are located in the sound cave are recorded as an initial step. Note that these Green's functions will not only contain the direct wave between the two points on the two different surfaces. Although the direct wave typically will be the most significant part of the Green's functions, it is the reverberations from the surrounding acoustic environment in the desired state that are the most interesting part in this example.
Green's functions between the two surfaces are recorded by physically mimicking the geometry of the two surfaces in the sound cave. By emitting a sound-pulse in one location on one of the surfaces and recording it at one or several points on the recording surface, it is possible to record all the required Green's functions that are required to characterize an acoustic environment such as a mountain chain or the La Scala theatre. This step can be performed by emitting from the recording surface 11 and recording from the emitting surface 12 . If it is however more convenient to maintain the transducers in their actual role, the reciprocal of the desired wave propagators WP(−) can be recorded and reversed before use in the computer system 18 .
Instead of physically recording Green's functions in a desired state, it is also possible to generate completely synthetic Green's functions corresponding to a model of a desired acoustic landscape. This may be of particular interest in gaming and entertainment applications. Since synthetic Green's functions may be a lot simpler in structure, it may be possible to reduce the computational requirements of the sound cave significantly.
The sound cave 10 can be described as a machine creating the virtual acoustic environment emulating the desired state in which the Green's functions were recorded. On the surface 12 at the edge of the wall (just inside), transducers (o) are evenly spaced typically according to the Nyquist sampling criterion. These transducers are used to emit sound (referred to as the emitting layer of transducers). In the preferred embodiments, only monopole transducers are used to emit sound. However, in some embodiments it is necessary to use both monopole and dipole transducers to achieve the desired directivity of the emitted sound in the directions out-going or in-going compared to the emitting surface.
Another surface 11 of transducers (x) is positioned a short distance inside the emitting surface. The transducers (x) record the sound in the sound cave and the layer 11 is referred to as the recording layer of transducers. It should be noted that both transducers that record pressure and particle velocities—equivalent to monopole and dipole receivers—are needed on the recording surface or alternatively two layers of pressure sensitive transducers so that the pressure gradient normal to the recording surface can be recorded.
The transducers may be mounted on thin rods that are practically acoustically transparent at the frequencies of interest. Again, the transducers on the recording surface are spaced typically according to the Nyquist sampling criterion. Note that one or several sides of the sound cave may be absent of transducers if its boundary conditions are the same in the desired and virtual states (e.g., a solid stone floor at the bottom or an open sky at the top). To reduce the number of transducers, it is possible to reduce the spread of transducers on the surfaces to a single line of transducers x,o (again best separated according to the Nyquist sampling criterion) on one or both of the surfaces 11 , 12 .
As the person inside the sound cave calls out, the sound will be recorded on the recording surface. A computer is used to extrapolate the recorded wavefield from the recording surface to the emitting surface using a wavefield propagator (derived from Green's theorem or equivalent formulae known as Betti's theorem, Kirchhoff's scattering integral or acoustic representation theorem, etc.). Other examples of wavefield propagators can be found in Grote and Kirsch (2007), Grote and Sim (2011), Thomson (2012) and Utyuzhnikov (2010). Using for example the acoustic representation theorem the following expression for the emitted wavefield is obtained:
p emt ( x emt ,T )=∫ 0 T ∂D rec [ G vir ( x emt |x rec ,T −τ) v k rec ( x rec ,τ)+Γ k vir ( x emt |x rec ,T −τ) p rec ( x rec ,τ)] n k dAdτ
where p emt (x emt ,T) is the desired extrapolated pressure data at a location x emt and at time T, ∂D rec is the surface of a so-called recording surface (defined below) with normal vector component to the surface n k , dA represents an infinitesimal surface area integration element of the recording surface and T is the time integration variable (coordinates on the recording surface are denoted x rec ). The variables p rec and v k rec represent that data recorded by the transducers on the recording surface in terms of pressure and particle velocity (the later quantity can also be computed from either pressure gradient recordings or recordings of particle displacement, particle acceleration, etc.). The variables G vir and Γ k vir are the pre-determined Green's functions between the recording and emitting surfaces of the desired (virtual) state in terms of pressure-to-pressure and particle-velocity-to-pressure. A similar equation to equation [1] can be used to extrapolate the wavefield in terms of particle velocities which is needed to emit the wavefield on dipole-types of receivers.
The extrapolated wavefield will constitute an out-going wavefield and an in-coming (reverberated) wavefield. It is preferred that the physically propagating wavefield is out-going only and that it does not reflect from the physical boundary of the sound cave.
In one embodiment, the emitting transducers are mounted on a so-called pressure-release (free) boundary. An out-going wave physically propagating in the sound cave will be absorbed as it reaches the boundary and reflects while undergoing a phase reversal (due to the −1 reflection coefficient of the boundary in terms of pressure) destructively interfering with the wavefield data for the out-going wave which is extrapolated and emitted as if the wave was out-going. Note that only emitting transducers of a monopole-type are needed in this embodiment.
In a variant of this embodiment the transducers are mounted on a rigid boundary where the reflection coefficient is −1 in terms of particle velocity and cancellation of the physically propagating wave can be achieved analogously to the embodiment for a pressure-release or free boundary. If a boundary is neither perfectly rigid nor perfectly free but where the reflection coefficient is known an appropriate transfer function can be applied to the extrapolated wavefield so that the direct wave from the emitting surface will destructively interfere with the direct propagating wavefield.
In another embodiment, the emitting transducers are located just inside a sound absorbing wall coinciding with the physical limit of the sound cave. The wavefield extrapolated from the recording surface to the emitting surface will contain both the (out-going) direct wave extrapolated to the emitting surface as well as both out-going and in-going reverberations as the direct wave interacts with the desired state. It is sufficient to think of waves originating from (primary or secondary) sources external or internal to the recording surface when analyzing how they will interfere with the physically propagating waves in the sound cave. The physically propagating direct wave between the recording surface and the emitting surface are best designed to destructively interfere with its extrapolated counter part. This can be achieved by reversing the phase of the part of the Green's function that corresponds to the direct wave only. However, whereas this method is sufficient for sources internal to the recording surface, it will have the opposite effect for sources external to the recording surface (Thomson, 2012).
However this undesired effect is only relevant for the wavefield that is out-going at the emitting surface. In the sound cave the problem of constructive interference between extrapolated and physically propagating out-going waves can be avoided for example by using the sound-absorbing layer outside the emitting surface. Advantageously the direct wave in the Green's function can be muted as it will be purely outgoing.
It is also possible to pre-record empirical Green's functions in the sound-cave and to isolate undesired parts that are due to reflections from imperfections of the nature of the walls or non-transparency of mounted transducers. These can then be removed from the extrapolated wavefield by subtracting isolated parts of the empirical Green's functions of the sound cave from the Green's functions of the desired state.
A sound-absorbing layer can also be employed to reduce the complexity of how the wavefield is introduced in the case where emitting transducers are not located on a rigid wall or pressure-release boundary. In contrast to the case where the emitting transducers are mounted directly on a wall and only monopole or dipole transducers are required, both dipole and monopole emitting transducers will be required in free space to ensure that out-going and in-going waves are emitted in the correct direction. However, before emitting the wavefield the out-going and in-going contributions can be computed. The in-going part, which is the only of interest, can be isolated and emitted from the emitting monopole transducers. Since no dipole emitting elements are present, it will radiate in both the in-going and out-going direction. However, the out-going contribution will directly reach the sound-absorbing layer.
The in-coming wavefield on the other hand is exactly the reverberation from the desired (or virtual) state of the person calling out. As shown in the figures as echo from a mountain chain, this wavefield will again propagate inwards to the person who will hear his/her own echo from the desired (or virtual) state.
The wavefield can be split into direct wavefield and/or in-coming or out-going wavefield using known methods such as described for example by:
Amundsen, L., 1993, Wavenumber-based filtering of marine point-source data. Geophysics, 58, 1335-1348; or by Osen, A., Amundsen L., and Reitan, A., 2002, Toward optimal spatial filters for demultiple and wavefield splitting of ocean-bottom seismic data: Geophysics, 67, 1983-1990.
Sounds for (virtual) sources exterior to the emitting surface can also be added to the extrapolated wavefield so that the sound cave projects sound sources external to the emitting boundary into the cave. This is simply a matter of using the Green's functions of the virtual/desired state to extrapolate an external source onto the transducers on the emitting surface. For example, the song from flying birds can be projected into the sound cave and can for example be added to the reverberations of any sounds emanating from within the sound cave. This external source will be in most cases based again on prerecorded signals and not actually present when a listener uses the sound cave.
The extrapolation process can be for example implemented by first noting that any operation on the wave includes the use of digitized signals discretized in time (as opposed to analogue signals). Therefore it is possible to be stepping forward in time by discrete time-steps when projecting a sound environment into the sound cave. The size of the time-step is related to the maximum frequency of interest in accordance to the Nyquist sampling theorem (in time).
The coupling of the sound cave with the virtual domain is achieved by using equation (4) in van Manen et al. (2007), which is a time-discrete version of Green's second identity:
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where the caret denotes time sampled quantities, {circumflex over (p)}( x rec ,m) is the sampled pressure at time-step m and location x emt , Ĝ( x emt , l−m; x rec , 0) is the Green's function at time step l−m between x emt and x emt , x rec is a location on the integration surface S rec with normal n j , and ∂ j is a spatial gradient operator normal to the integration surface. Note that the usual time-integral in Green's second identity is implicit within the recursion in equation [2].
Green's functions for the numerical simulation connecting the recording and emitting surfaces S rec and S emt can be pre-computed using a wave propagation simulation technique. Acoustic waves are recorded along S rec at discrete time steps l. These data are extrapolated to S emt by means of equation [2] using the pre-computed Green's functions. The extrapolated data comprise a discrete time series that is added to a stored buffer {circumflex over (p)} emt ( x emt , l, m) containing future values to be emitted along S emt . At each time-step, equation [2] is thus evaluated as many times as the number of samples in the discrete Green's functions. At time-step l+1 data from the stored buffer are emitted on S emt . In this way the acoustic environment within the recording surface can be linked with the desired virtual environment.
Referring again FIG. 2 , the mountain chain outside the emitting surface 12 does not exist in the real acoustic environment of the listener but acoustic waves are virtually projected onto the mountain chain in accordance with our invention. The dashed curved arrow from the recording surface 11 to the mountain chain and back to the emitting surface indicate the (virtual) acoustic path of the wave 14 from the event 13 would have taken place if the mountain chain were present and if the confinements of any room in which the recording and emitting surface are placed during reproduction would not exist.
The extrapolation method presented here operates on the out-going wave recorded on the recording surface 11 . In the embodiment where emitting transducers are mounted on a pressure-release or rigid wall, the extrapolated-outgoing wavefield will naturally absorb the physically propagating direct wave from the recording surface to the emitting surface. In the embodiment where a sound-absorbing layer is used outside the emitting surface, both the physically propagating as well as the extrapolated direct out-going wave is attenuated in the sound-absorbing layer.
The in-coming arrow represents the echo from the mountain chain and will propagate back inside the sound cave so that the listener can hear it. Note that another beneficial feature of equation [1] is that acoustic energy coming from the exterior of the recording surface will not be extrapolated back in the outward direction.
It is worth noting that the sound cave is completely general in terms of the numbers of sources or listeners inside the sound cave and will account for the complete interaction with all sources and listeners with each other and the desired acoustic environment.
To further illustrate the present example and how the extrapolation integral in equation [1] is solved and implemented at every discrete time-step through the following sequence of steps (the steps are also described in the flowchart in FIG. 3 .
(1) The acoustic wavefield at time t (think of this as a spike with amplitude of the acoustic wavefield at the time but 0 at all other times) is recorded at the recording surface 11 and extrapolated using equation [1] to the emitting surface for all future time steps t+dt, t+2dt, t+3dt, . . . , t+Ndt, where Ndt is the length of the Green's function (maximum time that is allowed for reverberations to return). (2) The record of all future values at the emitting surface 12 of the extrapolated wavefields from recording surface 11 are updated by adding the extrapolated wavefield from step (1). (3) Then a step forward to time t+dt is taken and the next future prediction is used to emit sound at the emitting surface 12 (4) The process repeats starting from step (1)
Considering an example where the sound cave is a cubic room with length, depth and width of 2 m, the distance between the emitting and the recording layers is 25 cm and the “cube” defined by the recording layer 11 therefore has a width of 1.50 m. Assuming further that the floor is a solid stone floor in both the virtual and desired states, no transducers are needed on that surface in the sound cave. The emitting layer 12 has dimensions 2 m by 2 m by 2 m (emitting transducers (o) on 5 sides) whereas the recording layer has dimensions 1.5 m by 1.5 m by 1.75 m (recording transducers (x) on 5 sides).
Being interested in emulating frequencies up to for example 1 kHz, a temporal (Nyquist) sampling rate of 0.5 ms is required. The speed of sound is 340 m/s and the shortest wavelength is therefore 0.34 m. The required spatial (Nyquist) sampling rate is therefore 0.17 m. A number of transducer elements (o) on the emitting surface 12 is: 5*(1+round(2/0.17))*(1+round(2/0.17))=845. Similarly, the number of transducer elements (x) on the recording surface is 544. The Green's functions are going to be 5000 samples long (2.5 s). This would allow echoes from objects up to 425 m away to be captured. Longer reverberation times and multiple echoes would require longer Green's functions.
The computations for the extrapolation needs to be done real-time bounded by the propagation distance between the recording and emitting surface (note that the distance between recording and emitting surfaces needs to be greater than the distance that sound propagates during the temporal sampling time interval). The number of calculations required each time step is: (number of transducers on emitting surface)*(number of transducers on recording surface)*(number of samples in Green's function)*(number of operations in integrand for extrapolation). In the present example the number of calculations are: 845*544*5000*3−6.9*10^9. With a sampling interval of 0.5 ms computations are generated at a computational rate of at least 14Tflop to create the correctly propagated wave at the correct time. The distance between the recording and emitting surfaces 11 , 12 must be greater than the propagation velocity times the temporal sampling frequency in order to be able to predict the wavefield at the emitting surface from recordings at recording surface 11 .
Remote compute servers or internet switches typically introduce computational latencies that lead to accumulative delays that are greater than the sampling interval. Light in vacuum propagates 150 km in the sampling rate of 0.5 ms which introduces an upper bound for how far away the computational facility can be located from the sound cave. Clearly, the computing engine 18 should preferably be co-located with the sound cave 10 .
It is preferred for the medium between the recording and transmitting surface to have the same propagation characteristics as the same part of the medium where the Green's functions were recorded in the desired state. Usually this medium will be air.
Instead of recording and transmitting transducers, laser devices can be used to record and emit sound waves at desired locations. Another alternative is to use hypersonic sound (hss), also known more generally as “sound from ultrasound”, where a beam of ultrasound is projected on a wall for example and sound is generated non-linearly on the wall and this starts radiating.
Applications for a sound cave embodiment can include:
Entertainment industry such as computer games (gaming) or virtual reality experiences: A particular example of a gaming application could include a large room where several people are present at once for a virtual reality, interactive movie or gaming experience. Note that if the floor is reflecting and if the ceiling is coated with an absorbing material, virtual states that share these features (e.g., open sky and stone floor) can be generated with a sound cave where only the walls on the sides are covered with emitting and receiving elements. If the height of the room remains small (say 2 m), the dimensions of the room in the horizontal directions can be made quite large without the surface area covered by the recording and transmitting elements becoming excessively large; Video conferencing. The present invention can complement a video conference (using for example an holographic video reproduction) with an immersed acoustic experience Acoustic design or optimization. For example, a music band preparing a concert tour could optimize where to position loudspeakers in order for the acoustic experience to be optimal at different select positions at a venue. Green's functions would be physically recorded at different locations in the concert venue. The sound cave could then be used to simulate what the sound experience would be for a person located at that position. Acoustic environments can also be projected into a recording studio for film or music productions. Training of blind people by immersing them in the acoustic environment that they will be walking through, without risk of accidents or being run over by cars. By switching emitting and recording surfaces so that the recording surface is the outer surface, it is possible to create an “acoustic invisibility cloak”. By using Green's functions of an empty space for the interior of the emitting surface, objects located inside will not be detectable by acoustic waves (e.g., sonar). By muting all or most of the outgoing waves and in-coming reverberation the system can simulate an anechoic chamber.
As the present invention has been described above purely by way of example, and the above modifications or others can be made within the scope of the invention. The invention may also comprise any individual features described or implicit herein or shown or implicit in the drawings or any combination of any such features or any generalisation of any such features or combination, which extends to equivalents thereof. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments. Alternative features serving the same, equivalent or similar purposes may replace each feature disclosed in the specification, including the drawings, unless expressly stated otherwise, for example using the principles as described above to elastic waves propagating in solids or electromagnetic waves (e.g., light or microwaves). Unless explicitly stated herein, any discussion of the prior art throughout the specification is not an admission that such prior art is widely known or forms part of the common general knowledge in the field.
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A method of and a system for generating an acoustic wave representing reverberations from a desired acoustic environment are described including having a recording surface ( 11 ) defined by a spatial distribution of recording transducers (o) and an emitting surface defined by a spatial distribution of emitting transducers (x), wherein the emitting surface ( 12 ) defines a volume within which the recording surface ( 11 ) is located, recording an acoustic wave ( 14 ) originating from within a volume defined by the recording surface ( 11 ) using the recording transducers (x), extrapolating the recorded wave ( 14 ) to the emitting surface using wavefield propagator system (IS) representing the desired acoustic environment, and emitting the extrapolated wave from the emitting transducers (o).
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The present invention is directed to thermal printing and, more particularly, directed to a heat-sensitive transfer media to facilitate such printing.
Printing through the use of heat, rather than mechanical impact, has a number of advantages. Thermal printing, for example, eliminates the need for messy inks, or ink-impregnated ribbons, which are many times awkward to handle and change in the printing apparatus.
Secondly, mechanical impact-type printing usually involves quite complicated mechanizations in order to properly create images through an impregnated ribbon utilizing solid alphanumeric characters, or a dot-matrix system.
An additional advantage of thermal printing is its relatively noise-free operation. This can be quite important where a number of machines are employed in the same area.
In thermal printing, a heat transfer media, such as heat-sensitive process ink disposed on a plastic, or paper, ribbon is utilized with a thermal print head. The thermal print head heats selected portions of the ribbon, thereby causing the heat-sensitive ink, or heated portions, to melt, or soften, and transfer onto paper, or other objects to be printed.
Typically, the heat-sensitive ink comprises a binder which is solid at room temperature, but is softened or fluid above about 60° C. The melt and flow characteristics of the process ink are controlled by a number of additives in order to impart physical properties to the ink to enable complete transfer of the ink, when heated, from the ribbon, or substrate, to the paper stock, or object to be printed.
A number of binders have been utilized in heat-sensitive medias including waxes, such as carnauba waxes, microcrystalline wax, haze wax, beeswax, ceresine wax, spermaceti, polyethylene and oxidized polyethylene.
Since the binder itself usually is colorless, a pigment is suspended within the binder to impart color to the ink. A number of pigments are suitable for thermosensitive process inks which range in color and include black, magenta, cyan and yellow, among others.
In the last stages of pigment manufacture, the pigment is precipitated from solutions and then passed through a filter press to produce what is commonly called "presscake", which may contain up to 80% water.
To increase the density of the pigment, the presscake is typically added into an oil-based vehicle and is vigorously mixed at a temperature between about 60 and about 100° C. to "flush" the water out of the pigment and cause the pigment to enter the oil phase.
In the trade, the pigment-laden oil is typically referred to as "dry color" or "flush".
In the manufacture of the heat-sensitive ink, this flush is then added to a binder along with other additives to form a heat-sensitive transfer media, which is typically applied to a ribbon substrate, or the like.
It should be appreciated that the pigment is present in the binder as particulates and color image quality and clear definition of the images to be printed is in part dependent upon the pigment particulate size in the heat-sensitive process ink.
This is particularly important in dot-matrix-type printing.
Current state-of-the-art thermal print heads are capable of defining 400 dots per inch, i.e., they are capable of individually heating 400 points per inch along a heat-sensitive transfer media. Hence, a single dot may have a dimension of approximately 0.0635 millimeters.
As technology improves in the thermal print head area, it is expected that smaller dot sizes may be achieved. It should also be apparent that dot size and dot density are directly related to the image quality produced by a dot matrix thermal print head.
Heretofore, the heat-sensitive transfer media has included pigment with a particle size of up to 0.1 millimeter in size and pigment concentration of at most about 15 percent by weight. Clearly, this heat-sensitive transfer media cannot take full advantage of the state-of-the-art thermal print heads, which have a capability of printing up to 400 dots per inch.
Hence, there is a need for heat-sensitive transfer media having a pigment particulate size and concentration sufficient to enable image quality as may be afforded by the state-of-the-art thermal print heads and for accommodating thermal print heads which may be developed having even a greater dot density capability.
The present invention is for a process for manufacturing a heat-sensitive transfer media which includes pigment having a very small particular size, suspended in a binder, and the product made by this process.
While conventional elements of the present heat-sensitive transfer media may be known in the art, it is the process itself which creates the fine particulate pigment dispersion in the binder, which has been discovered.
SUMMARY OF THE INVENTION
In accordance with the process of the present invention for the manufacture of a heat-sensitive transfer media, a solid wax binder is heated to form a molten-wax binder and a mixture of pigment and water is provided and added to the molten wax binder.
Thereafter, the molten wax binder and the mixture of pigment and water are agitated under conditions of temperature and pressure suitable for causing the pigment to leave the water and disperse as particulates in the molten wax binder.
The water is separated from the molten wax binder and additives are blended with the molten wax binder to form a molten heat-sensitive transfer media.
Thereafter, the molten heat-sensitive transfer media is cooled to form a solid heat-sensitive transfer media.
The conditions suitable for causing the pigment to transfer from the water and disperse in the molten wax binder include maintaining a temperature sufficient to keep the wax binder in the molten state at atmospheric, or reduced pressure. In addition, the molten heat-sensitive transfer media may be coated onto a suitable substrate for the cooling thereof.
Specifically, the process in accordance with the present invention may utilize a carnauba wax derivative as binder and the temperature during mixing is maintained about 90° C.
The mixture of pigment and water, or presscake, suitable for the process of the present invention may include about 30% by weight pigment and about 70% by weight water.
The process of the present invention is distinguished over prior art processes by the method in which the pigment is incorporated into the binder to produce a very fine particulate pigment therein.
Typically, prior art processes for the manufacture of a wax binder heat-sensitive transfer media, utilize oil-based pigment, or dry color. This dry color is added to the molten wax binder and agitated to disperse the pigment therein. This results in significantly larger pigment particulates in the wax binder as will be hereinafter documented.
More specifically, the process in accordance with the present invention includes utilizing additives, such as tall oil, Tergitol wetting agents and Cosperse 7000, the additives being added as hereinafter discussed, to enhance the transfer of the qualities of the heat-sensitive transfer media.
In the present process, the mixture of pigment and water is added in an amount sufficient to result in a heat-sensitive transfer ink having up to about 60% by weight pigment.
When a wetting agent such as Tergitol 15-S-7 or Tergitol TMN6 and tall oil are utilized as additives, they may be added in an amount to result in a heatsensitive transfer ink having about 70% by weight binder, 10% by weight pigment, 10% by weight tall oil and about 10% by weight Tergitol.
The advantage of the process of the present invention is that the resulting heat-sensitive transfer media comprises pigment having a particle size of less than about 0.06 millimeters and as small as about 1.0 micron, with pigment concentration up to about 60% by weight, and the product of the process of the present invention is considered part of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, the process for manufacturing heat-sensitive transfer media and the resulting heat-transfer media are provided.
The composition of the heat-sensitive transfer media comprises a suitable wax binder, such as carnauba wax, carnauba wax derivatives, microcrystalline wax, haze wax, beeswax, ceresine wax, or spermaceti.
Specifically, the heat-sensitive transfer media may comprise carnauba wax, flake No. 3, available from Vivion Chemical Corporation, wax S or KSL wax, available from American Hoechst.
Suitable additives useful in the present invention are Tergitol 15-S-7, Tergitol TMN-6, available from Union Carbide; or Actinol FA3, tall oil, available from Arizona Chemical; 2-Ethoxyethanol, available from Union Carbide Corporation; and Cosperse-7000, available from U.C.I. Americas.
While any number of additives may be useful, it has been found that Tergitol 15-S-7 enhances the complete transfer of the ink from the substrate onto the paper when activated by heat, and the Cosperse-7000 is added as a viscosity builder to enable a smooth coating and cohesion of the ink onto the paper, or object to be printed.
The 2-Ethoxyethanol is added as an emulsifier/ stabilizer for the binder.
It is of utmost importance that the pigment particle size suspended in the binder is suitable for the advantage of enabling printheads having a dot size of about .0635 millimeters, hence, the particle size is preferably less than about 0.06 millimeter.
It has been found that the condition necessary to achieve this particulate pigment size is to maintain the wax in a molten state, in the case of carnauba wax, about 90° C., while vigorously mixing and adding presscake into the wax. While the hereinafter set forth examples were made utilizing a temperature of approximately 90° at atmospheric pressure, it is not intended to limit the invention thereto. The effects of higher temperatures and pressures may result in varying pigment particulate size, although investigation of this range of perimeters is not presented herein.
The range of temperatures suitable for carrying out the present invention is between the melting point of the wax and the decomposition temperature of the particular pigment utilized.
Any number of pigments may be utilized in presscake form in the present invention. Specific ones that have been found to be useful include Sunfast blue, NC-449-1281, lemon metallic yellow (AAOA) presscake 475-0586 S 15002 and lithol rubine (red) presscake No. 419-04191 T15228, all available from Sun Chemical of Cincinnati, Ohio.
It is to be appreciated that the pigment formulations are in many cases trade secrets of the companies providing them, however, the identified pigments herein are commercially available. In these presscake pigments the water content ranges between 50% to 80% by weight.
Pigment concentrations may vary depending upon the density of a particular pigment and generally are between about 5 and about 15% by weight pigment in the heat-sensitive transfer media.
EXAMPLE 1
Carnauba wax was heated to about 90° C. and thereafter Sunfast blue pigment presscake having a watercontent of 65.6% was added thereto and the liquid mixture agitated with a 2000 RPM mixer to cause the pigment to leave the water phase and enter the wax as a particulate, some of the water separated by evaporization and the remainder separated by applying a vacuum to the mixture.
Thereafter, the pigment laden wax was mixed with tall oil (Actinol FA3) and Tergitol TMN-6 and coated on a polymer substrate and allowed to cool.
The composition of the heat-sensitive transfer media was 65% by weight carnauba wax, 11% by weight Cosperse-7000, 7% by weight tall oil, 7% by weight Tergitol TMN-6, and 10% Sunfast blue pigment.
The coating was air cooled to room temperature (22° C.) in about 5 to about 10 seconds. After the coating had cooled, it was observed under a microscope and the particle size and distribution documented. It was found that the pigment particulate size was less than about 0.06 mm.
Under examination with a Leeds and Northrop Instruments MICROTRACK particle size analyzer, the pigment particulate size was found to be about 1.0 micron. (80%-1.1 micron, distribution, 3%-0.2 micron, 4%-6.0 micron).
EXAMPLE 2
The process set forth in Example 1 in which the Sunfast blue was added in amounts resulting in the heat-sensitive transfer media having a concentration of between 5% and 60% by weight pigment, 11% by weight Cosperse-7000, 7% by weight tall oil, 7% by weight Tergitol TMN-6 and correspondingly 70% to 15% carnauba wax.
Microscope examinations showed that the particle size of the pigment was less than about 0.06 mm.
Under examination with a Leeds and Northrop Instruments MICROTRACK particle size analyzer, the pigment particulate size was found to be about 1.0 micron. (Distr. similar to Example 1).
Similar results were found when the presscake utilized was lithol rubine (red) and lemon metallic yellow.
EXAMPLE 3
The process set forth in Example 1 was carried out utilizing wax S, tall oil and Tergitol TMN-6, to result in a heat-sensitive transfer media having a composition of 70% by weight wax S, 10% by weight tall oil, (Actinol FA3), 10% by weight Tergitol TMN-6, and 10% by weight pigment.
After the coating had cooled, it was observed under a microscope and the particle size and distribution documented. It was found that the pigment particulate size was less than about 0.06 mm.
Under examination with a Leeds and Northrop Instruments MICROTRACK particle size analyzer, the pigment particulate size was found to be about 1.0 micron. (Distr. similar to Example 1).
EXAMPLE 4
The process set forth in Example 3 can be carried out utilizing KSL wax, tall oil and Tergitol TMN-6 to result in a final heat-sensitive transfer media having a composition of 70% by weight KSL wax, 10% by weight tall oil (Actinol FA3), 10% by weight Tergitol TMN-6 and 10% by weight pigment.
It is expected that particle size analysis would show a pigment particulate size of about 1.0 micron. (Distr. similar to Example 1).
EXAMPLE 5
Carnauba wax was heated to about 50° C. and thereafter Sunfast blue pigment dry color was added thereto and the liquid mixture agitated with a 2000 RPM mixer.
Thereafter, the pigment laden wax was mixed with tall oil and Tergitol TMN-7 and air cooled on a polymer substrate.
The final composition of the heat-sensitive transfer media was 65% by weight carnauba wax, 11% by weight Cosperse-7000, 7% by weight tall oil, 7% by weight Tergitol TMN-7 and 10% Sunfast blue pigment.
After the coating had cooled, it was observed under a microscope and the particle size and distribution documented. It was found that there were between 60 and 100 pigment particles per square inch having a particle size greater than 0.06 mm and the maximum particle size was about 0.1 mm.
The method of making a heat transfer media according to prior art technique as illustrated in Example 5, results in large pigment particulates in the end product compared to the pigment particulate size found in heat-sensitive transfer media made in accordance with the present invention as illustrated in Examples 1-4.
Although there has been described hereinabove a specific process for the manufacture of heat-sensitive transfer media and the product of the process for the purpose of illustrating the manner in which the invention may be used to advantage, it should be appreciated that the invention is not limited thereto. Accordingly, any and all modifications, variations or equivalent arrangements which may occur to those skilled in the art, should be considered to be within the scope of the invention as defined in the appended claims.
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A process is provided for the manufacture of heat-sensitive, heat-transferred media which includes a solid wax binder pigment and additives. The process provides for the mixing of molten wax binder with a mixture of pigment and water to transfer the pigment from the water into the molten wax binder as particulates. The water is separated and removed from the wax and the pigment-ladened binder mixed with additives such as Tergitol, tall oil and Cosperse to produce a heat-sensitive transfer media. When coated on a polymer backing, the heat-transfer media had a very fine pigment particulate size.
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BACKGROUND OF THE INVENTION
This invention relates to the fabrication of microminiature devices and, more particularly, to an apparatus and a method in which fine-line patterns for integrated circuits are precisely delineated by dry etching processes.
Considerable interest exists in employing dry processing techniques for patterning workpieces such as semiconductor wafers. The interest in dry processing stems from its generally better resolution and improved dimensional and shape control capabilities relative to standard wet etching. Thus, dry etching is being utilized increasingly for, for example, fine-line pattern delineation in the processing of semiconductor wafers to form very large-scale-integrated (VLSI) devices.
Various dry etching processes that involve radio-frequency (rf)-generated plasmas in a reaction chamber are known. These so-called plasma-assisted processes include reactive sputter (or ion) etching. In reactive sputter etching, the workpieces to be patterned are placed on the rf-driven cathode electrode in the reaction chamber. In another plasma-assisted process, typically referred to as plasma etching, the workpieces are placed on the grounded anode electrode in the reaction chamber. These and other processes suitable for making VLSI devices are described by, for example, C. M. Melliar-Smith and C. J. Mogab in "Plasma-Assisted Etching Techniques for Pattern Delineation," Thin Film Processes, edited by J. L. Vossen and W. Kern, Academic Press, New York, 1978, pages 497 to 552.
As heretofore practised, plasma-assisted etching processes designed to pattern micron and sub-micron features in VLSI devices have often been plagued with relatively poor yield characteristics. One major obstacle to achieving better results in these processes has been the seemingly unavoidable presence of contaminants in the reaction chamber of the etching apparatus. These contaminants constitute, for example, pieces of material etched away from various surfaces in the reaction chamber or chemical fragments that are generated in the chamber during etching. Such contaminants can, for example, deposit on the surface of a selectively masked layer to be etched and thereby effectively inhibit etching of the unmasked portions of the layer that underlie the deposited contaminants. As a result, the pattern etched in the contaminated layer may not be a precise reproduction of the pattern formed in the overlying mask. In many cases of practical importance, the portions of the layer that are prevented by contaminants from being etched away result in unacceptable patterns being delineated in the devices under fabrication. Or some of these unetched portions, constituting slivers or so-called "grass" regions, may break off or be transported laterally or penetrate subsequent layers during the device fabrication sequence, thereby causing faults in the devices.
For these and other reasons, considerable efforts have been directed by workers in the art aimed at trying to reduce contamination effects in the reaction chamber of a plasma-assisted etching apparatus. It was recognized that such efforts, if successful, would increase the yield and thereby decrease the cost of devices made in accordance with a fabrication sequence that includes dry patterning steps carried out in such etching apparatus.
SUMMARY OF THE INVENTION
Hence, an object of the present invention is an improved etching apparatus and method. More specifically, an object of this invention is a plasma-assisted etching apparatus and method characterized by low contamination in the reaction chamber of the apparatus during the etching process.
Briefly, these and other objects of the present invention are realized in a specific illustrative plasma-assisted etching apparatus and method designed to pattern aluminum or polysilicon in a plasma. For aluminum, the plasma is, for example, derived from a mixture of boron trichloride and chlorine. For polysilicon, the plasma is, for example, derived from a mixture of boron trichloride and chlorine or from chlorine alone. In accordance with a feature of the invention, at least some of the surfaces in the reaction chamber of the apparatus are coated with a layer of aluminum oxide. Contamination of wafers during the etching process is thereby substantially reduced.
BRIEF DESCRIPTION OF THE DRAWING
A complete understanding of the present invention and of the above and other features thereof may be gained from a consideration of the following detailed description presented hereinbelow in connection with the accompanying drawing, in which:
FIG. 1 shows a specific illustrative plasma-assisted etching apparatus made in accordance with the principles of the present invention;
FIG. 2 is a cross-sectional depiction of a portion of the FIG. 1 apparatus;
and FIG. 3 is a cross-sectional schematic representation of a conventional plasma spray gun by means of which selected surfaces of the FIG. 1 apparatus may be coated.
DETAILED DESCRIPTION
The principles of the present invention are applicable to the improvement of both standard plasma etching equipment and methods and standard reactive sputter etching equipment and methods. Herein, for purposes of a specific illustrative example, emphasis will primarily be directed to reactive sputter etching equipment that embodies the principles of applicants' invention. It should be clearly understood, however, that these principles are also advantageously applicable to plasma etching apparatus.
Moreover, various configurations of reactive sputter etching apparatus are known. These include so-called parallel-plate or pancake reactors of the type described in U.S. Pat. No. 3,598,710 and so-called multifaceted cylindrical reactors of the type described in a copending commonly assigned U.S. patent application of D. Maydan designated Ser. No. 105,620, filed Dec. 20, 1979, now U.S. Pat. No. 4,298,443. For purposes of a specific illustrative example, emphasis herein will primarily be directed to a reactor of the multifaceted cylindrical type. But it should be clearly understood that the principles of applicants' invention are also advantageously applicable to other reactors such as those of the parallel-plate type.
A specific illustrative multifaceted reactive sputter etching apparatus that embodies applicants' inventive principles is depicted in FIG. 1. In its overall configuration, the FIG. 1 apparatus is basically the same as that described in the aforecited Maydan application. The main difference between the apparatus shown in FIG. 1 and prior such equipment attributable to others resides in the fact that surfaces in the reaction chamber of FIG. 1 are coated with a layer of aluminum oxide. For certain etching processes, to be specified later below, such a coating has been determined to impart a particularly advantageous low-contamination characteristic to the etching process carried out in the depicted reaction chamber.
As described in detail in the aforecited Maydan application, the specific illustrative etching system depicted in FIG. 1 comprises a reaction chamber defined in part by a cylindrical housing 10 made of an electrically conductive material such as, for example, aluminum or stainless steel. The housing 10 can be raised upwards to provide access to a workpiece holder 12 that is centrally mounted within the depicted structure. The particular illustrative holder 12 shown in FIG. 1 includes six flat surfaces or facets. By way of a specific example, each such surface indicated in FIG. 1 is designed to have six 4-inch wafers mounted thereon. A tray or wafer-containing assembly 11 for mounting the wafers on the holder 12 will be described below in more detail in connection with FIG. 2.
Auxiliary equipment 14 constituting a part of the overall etching system shown in FIG. 1 includes a conduit 16 that contains therein fluid-carrying pipes and a conductive bus. The fluid carried in the pipes is utilized to cool the workpiece holder 12, and the bus is for the purpose of capacitively coupling a high-frequency potential to the holder 12.
Conduit 18 (FIG. 1), which is connected to a standard vacuum pump in the equipment 14, serves to establish a prescribed low-pressure condition in the housing 10. In addition, an inlet pipe 20 is utilized to introduce a specified gas or mixture of gases into the depicted chamber from the equipment 14.
The aforementioned bus is connected to the workpiece holder 12 shown in FIG. 1, and the housing 10 is connected to a fixed point of reference potential such as electrical ground. The workpiece holder 12 constitutes the cathode and the housing 10 constitutes the anode of the depicted apparatus. As is well known, the anode-to-cathode area ratio is designed to exceed unity.
The FIG. 1 apparatus may also advantageously include a grid element 26 whose structure and function are described in detail in the aforecited Maydan application.
The wafer-mounting tray 11 of FIG. 1 is represented in more detail in FIG. 2. As indicated in FIG. 2, the tray 11 comprises a base plate 28 made, for example, of aluminum. Six wafer-holding recesses are formed in the plate 28. These recesses are typically cylindrical and just slightly larger in diameter than the respective wafers designed to be placed therein. The depth of the recesses is approximately the same as the thickness of the wafers. One such recess 30, having a wafer 32 therein, is indicated in FIG. 2. A top plate 34 containing six apertures therethrough in aligned registry with the recesses in the plate 28 is also shown in FIG. 2. Illustratively, the top plate 34 is secured to the base plate 28 by screws (one of which, designated 36, is shown in FIG. 2).
The diameter of each aperture in the top plate 34 is slightly less than the diameter of the wafer contained in the recess immediately thereunder. Accordingly, the plate 34 serves to retain the workpieces to be etched in place in the base plate 28. A major portion of the top surface of each retained workpiece is thereby exposed through its respective aperture in the plate 34. When the wafer-containing assemblies are secured in place on the facets of the holder 12, the exposed surfaces of the retained workpieces are mounted in place for etching in the apparatus of FIG. 1.
In accordance with the principles of the present invention, some or all of the internal surfaces in the reaction chamber of the FIG. 1 apparatus are coated with a layer of aluminum oxide. These surfaces include the surfaces of the top plates included in the wafer-holding assemblies (for example, the top plate 34 shown in FIG. 2), the inner surface of the housing 10 (FIG. 1), the surfaces of the grid element 26 and all other surfaces exposed to the etching plasma within the depicted reaction chamber.
To minimize contamination during etching, it is particularly important that the surfaces of the top plates included in the aforespecified wafer-holding assemblies be protectively coated. Hence, in accordance with the principles of this invention, at least the top plates of these assemblies are coated with a layer of aluminum oxide. (Of course, some or all of the other exposed surfaces in the reaction chamber may advantageously also be so coated.) Thus, as shown by way of example in FIG. 2, a layer 38 of aluminum oxide is coated on the top surface of the plate 34.
In accordance with the principles of the present invention, aluminum oxide coatings are especially well suited for use in the reaction chamber of a plasma-assisted etching apparatus designed to pattern aluminum or polysilicon. In particular, the coatings have been determined to be particularly advantageous for patterning these materials in certain specified plasmas. Before, however, setting forth detailed information concerning the plasmas, a specific illustrative procedure for forming suitable aluminum oxide coatings for use in the reaction chamber of a plasma-assisted etching apparatus will be described.
In accordance with the principles of this invention, aluminum oxide coatings can be applied to surfaces made, for example, of aluminum, magnesium, titanium, stainless steel, ceramic, plastic or glass. Coatings so applied, for example in accordance with the procedure detailed below, are characterized by high density, low porosity, good adherence to the underlying substrate and excellent structural integrity even under the harsh conditions typically present in the reaction chamber of a plasma-assisted etching apparatus.
An advantageous procedure followed by applicants for applying an aluminum oxide coating to substrates of the type specified above constitutes a specific version of a conventional plasma spray process. In turn, such a process is a particular form of so-called flame spraying which, as is known, is a generalized designation of methods wherein a material is brought to its melting point and sprayed onto a surface to produce a coating.
In the aforementioned plasma spray process, a direct-current (dc) potential is applied across a gap between a fluid-cooled conductive nozzle and an associated electrode. An arc is thereby produced. A plasma-generating gas comprising, for example, nitrogen or argon or nitrogen/hydrogen or argon/nitrogen or argon/hydrogen or argon/helium is directed to flow between the nozzle and the electrode of the plasma spray equipment. The arc excites the gas thereby producing a thermal plasma with temperatures adjustable up to approximately 16,000 degrees Celsius.
Powdered materials to be coated on a substrate are metered to the plasma spray equipment by a standard powder feed unit. The powder particles are introduced into the thermal plasma, melted by the high heat of the plasma and projected onto the substrate to form a coating. The molten particles impact the substrate with high force thereby producing excellent particle-to-substrate bonding.
In the plasma spray process, high thermal energy combined with high kinetic energy produce coatings of exceptional quality. For example, typical such coatings are relatively hard, dense and smooth. Though the plasma is extremely hot, the individual particles at the time of contact with the substrate are relatively cool thereby causing little, if any, dimensional distortion of the substrate and substantially preventing any chemical reaction from occurring between the impacting particles and the substrate.
FIG. 3 is a generalized schematic representation in cross-section of a specific illustrative plasma spray gun suitable for applying aluminum oxide coatings to substrates of the type mentioned above. A particular example of a commercially available such gun is the METCO 7MB plasma spray gun manufactured by METCO Inc., Westbury, Long Island, N.Y.
The gun shown in FIG. 3 comprises a conductive nozzle assembly 40. The nozzle 40 includes a passageway 42 through which a fluid such as water is circulated for cooling purposes. Further, the gun includes an electrode 44 having a passageway 46 for carrying a circulating coolant.
An arc is established between the nozzle assembly 40 and the electrode 44 of FIG. 1 by applying a dc potential between terminals 48, 49. The arc is represented by ragged lines 50. A plasma-generating gas or mixture of gases is caused to flow from left to right in the depicted gun via passageway 52 to the region wherein the arc is established. The resulting plasma flame is indicated by reference numeral 54.
Aluminum oxide to be coated on substrate 56 of FIG. 3 is fed to the depicted gun via passageway 58 in the form of powdered aluminum oxide suspended in a carrier gas. Suitable such carrier gases include, for example, argon or nitrogen. METCO type 3MP plasma powder feed unit is an example of the type of standard equipment available for feeding the aluminum oxide powder to the illustrated plasma gun with high reliability.
Dashed lines 60 in FIG. 3 indicate the extent of the spray stream including aluminum oxide emanating from the plasma gun. The sprayed aluminum oxide coating deposited onto the surface of the substrate 56 is represented in FIG. 3 by reference numeral 62.
In one specific illustrative procedure for forming an aluminum oxide coating utilizing a plasma spray gun of the type represented in FIG. 3, the distance d between the exit port of the nozzle assembly 40 and the surface of the substrate 56 was maintained in the range of 2-to-10 inches. The dc potential applied between the terminals 48 and 49 was 60-to-80 volts. Aluminum oxide powder comprised of particles having diameters in the range 0.05-to-5 micrometers (preferably 0.05-to-0.1 micrometers) was supplied to the gun at a rate of approximately four pounds per hour. The carrier gas for the aluminum oxide powder was a 1:1 mixture of nitrogen/hydrogen applied to the passageway 58 at a pressure of approximately 37 pounds per square inch. The plasma-generating gas was a 1:1 mixture of nitrogen/hydrogen applied to the passageway 52 at a pressure of about 80 pounds per square inch.
Advantageously, the starting point for providing powder to be applied to the FIG. 3 plasma spray gun comprises crystalline pieces of aluminum oxide. Such pieces occur naturally. One particularly advantageous form is a high-density high-temperature-resistant type typically referred to as the crystalline-β form. Ball milling and then successive screening of such naturally occurring crystalline pieces are effective to provide the powder required for application to the FIG. 3 gun.
Alternatively, non-crystalline naturally occurring pieces of aluminum oxide may be utilized as the starting material for the herein-specified procedure. In that case, the initial material is, for example, dissolved in sodium hydroxide, reprecipitated, dried, baked and then fired to produce crystalline pieces of the β form. Thereafter, ball milling and screening, as specified above, are carried out to provide the requisite powder.
Additionally, aluminum oxide powder comprising individual crystalline grains of the specified β form and suitable for the aforedescribed procedure is commercially available from, for example, The Linde Company, Speedway Laboratory, Indianapolis, Ind.
Moreover, even powder comprising individual relatively porous amorphous grains of aluminum oxide may be utilized in the plasma spray process specified herein. This is so because the plasma temperature to which the grains are subjected is typically greater than the amorphous-to-crystalline transition temperature thereof. So, even if the grains are not individually crystalline initially, they are typically converted to the crystalline β form during the plasma spray process. As a result, the final coating produced by the process is a relatively high-density one.
In accordance with the procedures set forth above, aluminum oxide coatings of various thicknesses can be deposited on a variety of substrates. In practice, the deposited coating has been made as thin as approximately 25 micrometers. Coatings approximately 2 millimeters thick have also been made. For one specific illustrative reactive sputter etching apparatus in which surfaces in the reaction chamber were coated with aluminum oxide, the coating thickness was advantageously established at approximately 175 micrometers.
In one specific illustrative coating procedure in which aluminum oxide is applied to an aluminum substrate, it is advantageous to clean the substrate before applying the coating thereto. This is done, for example, by light machining of the aluminum surface followed by glass-bead frit blasting and then cleaning of the surface with trichloroethylene.
Applicants have discovered that aluminum oxide coatings of the type specified above are particularly well suited for use in the reaction chamber of a plasma-assisted apparatus designed to pattern aluminum and/or doped or undoped polycrystalline silicon. In practice, such coatings have been determined to produce very little, if any, contamination of VLSI wafers during dry etching of aluminum and polysilicon layers.
More specifically, in accordance with the principles of the present invention, aluminum oxide coatings have been found to be advantageous for inclusion in the reaction chamber of a reactive sputter etching apparatus during patterning of an aluminum layer in a plasma derived from a mixture of boron trichloride and chlorine gases. Such mixtures suitable for anisotropic etching of aluminum are described in detail in U.S. Pat. No. 4,256,534. (Optionally, a relatively small amount of helium may be added to the boron trichloride-chlorine mixture.)
In one specific illustrative example in which an aluminum layer was anisotropically etched in a chamber that included surfaces coated with aluminum oxide, the aforementioned gas mixture included 75 percent by volume boron trichloride and 25 percent by volume chlorine. (Boron trichloride percentages in the range 0-to-90 percent and chlorine percentages in the range 100-to-10 also provide satisfactory results. Optionally, approximately 0-to-5 percent helium may also be included.) The flow of the mixture into the chamber approximated 75 cubic centimeters per minute. (A flow in the range 50-to-100 cubic centimeters per minute is satisfactory.) The pressure in the chamber was maintained at about 20 micrometers. (Satisfactory operation may also be carried out at a pressure in the range 5-to-50 micrometers.) The power per square centimeter at the surface to be etched was established at approximately 0.15 watts per square centimeter. (A powder density in the range 0.1-to-0.2 watts per square centimeter is satisfactory.) The direct-current bias of the cathode or wafer-holding electrode with respect to ground was measured to be about 210 volts. (A bias voltage in the range 60-to-350 volts dc is satisfactory.) Under these particular conditions, the aluminum layer was anisotropically etched in a substantially contamination-free manner at a rate of approximately 800 Angstrom units per minute.
In a VLSI structure that includes both aluminum and polysilicon layers to be etched, the polysilicon layer may also be anisotropically patterned in a plasma derived from the aforespecified boron trichloride-chlorine gas mixtures in a chamber that includes surfaces coated with aluminum oxide. Alternatively, the polysilicon layer may be etched in such a chamber in other plasmas.
An advantageous alternative plasma in which to etch polysilicon is derived from chlorine gas, as described in detail in a copending commonly assigned U.S. application of D. Maydan and D. N. Wang, Ser. No. 119,103, filed Feb. 6, 1980, abandoned and replaced by continuation application Ser. No. 300,307, filed Sept. 8, 1981, now U.S. Pat. No. 4,383,885. For undoped polysilicon, the edge profile of the etched material is anisotropic; for doped polysilicon, the edge profile can be controlled to occur in the range from completely isotropic to completely anisotropic, as set forth in the Maydan-Wang application.
In one specific illustrative example in which an undoped polysilicon layer was anisotropically etched in a chamber that included surfaces coated with aluminum oxide, the etching plasma was derived from an essentially pure chlorine gas atmosphere. The flow of the gas into the chamber approximated 40 cubic centimeters per minute. (A flow in the range 20-to-80 cubic centimeters per minute is satisfactory.) The pressure in the chamber was maintained at about 10 micrometers. (Satisfactory operation may also be carried out at a pressure in the range 5-to-40 micrometers.) The power per square centimeter at the surface to be etched was established at approximately 0.1 watts per square centimeter. (A power density in the range 0.05-to-0.2 watts per square centimeter is satisfactory.) The direct-current bias of the cathode or wafer-holding electrode with respect to ground was measured to be about 300 volts. (A bias voltage in the range 60-to-350 volts dc is satisfactory. Under these particular conditions, the polysilicon layer was anisotropically etched in a substantially contamination-free manner at a rate of approximately 500 Angstrom units per minute.
Finally, it is to be understood that the above-described arrangements and procedures are only illustrative of the principles of the present invention. In accordance with these principles, numerous modifications and alternatives may be devised by those skilled in the art without departing from the spirit and scope of the invention.
In a related application being filed concurrently herewith, applicants are disclosing and claiming a different material for coating surfaces in the reaction chamber of a plasma-assisted apparatus to achieve low-contamination etching of specified layers. This related application is designated Ser. No. 295,650.
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In a plasma-assisted etching apparatus and method designed to pattern aluminum or polysilicon, surfaces in the reaction chamber are coated with a layer of aluminum oxide. Contamination of wafers during the etching process is thereby substantially reduced. In practice, this leads to a significant increase in the yield of acceptable chips per wafer.
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FIELD OF THE INVENTION
[0001] The present invention is a storage system for organizing containers and lids of varying sizes, depths and shapes through the use of compartments. The compartments are configured in a variety of practical dimensions such as square, circular and flat. Retractable legs and sliding tracks offer additional storage capability.
BACKGROUND OF THE INVENTION
[0002] Storage is a very important part of the overall function of a kitchen. In addition, many people are faced with small storage space in their kitchen. This leads to clutter and disorganization. This is especially true when it comes to plastic containers and lids. These items often get thrown into various cabinets and cupboards based on where they can be fitted or, in some cases, crammed in. What then happens is that these containers are never consistently placed in one area as more items are added to the kitchen. In that scenario, kitchen users must then operate like they are playing a puzzle game in that they need to constantly find a place where each container or set of containers will fit. Furthermore, this also leads to the separation of lids from their relevant containers. Users then must not only hunt down the containers, but also must hunt down the corresponding lids. For this reason, there is a need for a system that eliminates this storage problem in the kitchen.
[0003] The present invention solves this problem by allowing the user to store containers and their lids into one set location that is aesthetic, organized, compact and adaptable.
[0004] Typically, users must stack circular containers together and find a place for them. The user also must stack rectangular containers together and find a place for them. Users then must stack different sized lids together and find a place for those. In the end, the circular containers often are in one cabinet, the rectangular containers are in a different cabinet and the lids are piled someplace else. Moreover, some kitchens with limited space also result in some circular containers in one cabinet while other circular containers are in another. Again, this causes frustration in the kitchen. And when someone who may not be as familiar with the location of kitchen items operates in that kitchen, the result is that containers and lids end up in different locations than the primary kitchen user intended. The present invention solves this problem by creating a system where a user may store all of the containers and lids in one constantly set location. This system also allows the user to collapse its wired exterior and deploy or retract the at least one front retractable leg and at least one rear retractable leg for improved adaptability, easy cleaning and optimal organization. This organization is such that circular containers, rectangular containers, square containers and lids of all shapes may be stored in one set location with limited kitchen space in mind.
[0005] The market reveals many types of storage items relating to silverware and eating utensils. These items include individual shapes or slots for forks, knives and spoons. Typically, these storage items for eating utensils sit within kitchen drawers. Unlike the present invention, these storage devices deal with utensils that are relatively small and can be fitted into a drawer. The present invention, in contrast, allows the user to organize various shapes and sizes of containers and lids by placing them in set compartments corresponding with those shapes and sizes. This means that the present invention can organize these containers and lids in cabinets. In addition, typical storage items do not adapt to small, confined cabinets while serving the one-location, organizational purpose of the present invention. For example, the present invention is a storage system that can be collapsed. This is especially helpful when the present invention accumulates dust and needs to be washed. At least one front retractable leg and at least one rear retractable leg also serve a function with the storage system of the present invention in that the user may adjust the height via deployment or retraction of the at least one front retractable leg and at least one rear retractable leg. This permits better accommodation and organization for other kitchen items that may need to be fitted within the same cabinet as the present invention. Thus, there is a need for the present invention as it solves a multitude of problems relevant to those with limited kitchen storage space.
SUMMARY OF THE PRESENT INVENTION
[0006] The present invention is a storage system relating to various types of containers and lids. More specifically, the present invention holds and organizes circular shaped containers, rectangular shaped containers, lids and other miscellaneous kitchenware. The present invention accomplishes this organizational and storage function through the shape, construction and depth of its compartments. In the preferred embodiment, at least four compartments each relate to differing shapes. These are the circular compartment, rectangular compartment, lids compartment and square compartment. This is to achieve optimal storage organization and compactness.
[0007] In addition, the present invention also includes at least one front retractable leg and at least one rear retractable leg. The preferred embodiment also adds at least two slideable tracks. The at least one front retractable leg and at least one rear retractable leg permit a user to adjust the height of the storage system. This is important because users often have different needs for storing other kitchen items such as trays and pans. In addition, users have very different amounts of cabinet space. The at least one front retractable leg and at least one rear retractable leg when retracted to a higher level permit more storage of other items below the storage system of the present invention. For those with shorter cabinets, the at least one front retractable leg and at least one rear retractable leg can be retracted to a shorter level to the point where the storage system is close to or touching the bottom of the cabinet.
[0008] The present invention in an additional embodiment also is collapsible. When the system of the present invention is collapsed, it is essentially formed into a more compact item that can be washed in the dishwasher or stowed for moving. In addition, this embodiment enables the user to collapse portions of each individual compartment. This aspect relates to catering the size of the compartments to fit various sizes of circular, rectangular or square containers in terms of their shapes and depths. By sliding the wired exterior of the system, the user can collapse individual compartments in order to alter the depth of that compartment.
BRIEF DESCRIPTION
[0009] FIG. 1 is a top view of the system of the present invention
[0010] FIG. 2 is a view of the present invention while legs are deployed.
[0011] FIG. 3 is a view of the present invention while legs are retracted.
DETAILED DESCRIPTION
[0012] FIG. 1 depicts a top view of the system of the present invention. As we see from this view, the system is comprised of a wired exterior ( 5 ). The material of the wired exterior ( 5 ) is preferably made of sturdy plastic or light metal. The wired exterior ( 5 ) essentially forms the various compartments of the present invention. As we see in FIG. 1 , the preferred embodiment of the wired exterior ( 5 ) is such that the compartments of the wired exterior ( 5 ) are shaped in terms of shape and depth. In this manner, the user can place objects—particularly plastic containers and lids—into these compartments and keep these items in one set location within the kitchen or other room. It should be noted that the wired exterior ( 5 ) is not limited to wide lengths in between its material as is shown in the figures, but instead can be much more filled in and expansive in regard to the width between the material of the wired exterior ( 5 ).
[0013] In FIG. 1 , the preferred embodiment shows a circular compartment ( 10 ), rectangular compartment ( 20 ), lids compartment ( 30 ) and square compartment ( 40 ). A user may stack at least one circular container in the circular compartment ( 10 ). These circular containers will be placed by the user in the circular compartment ( 10 ) in a manner so that the largest circular container fits neatly into the circular compartment ( 10 ) and smaller circular containers can then fit neatly inside the largest circular container with the opening facing either upward, downward or to any side. The circular compartment ( 10 ) is configured to descend downward at a depth below the top plane ( 80 ).
[0014] A user also can stack rectangular containers in the rectangular compartment ( 20 ). These rectangular containers will be placed, or stacked, by the user in the rectangular compartment ( 20 ) in a manner so that the largest rectangular container fits neatly into the rectangular compartment ( 20 ) and smaller rectangular containers can then fit neatly inside the largest rectangular container with the opening facing either upward, downward or to any side. The rectangular compartment ( 20 ) is configured to descend downward at a depth below the top plane ( 80 ).
[0015] A user also may place the lids for the circular or rectangular containers into the lids compartment ( 30 ). The lids will be condensed by the user flush together in any direction so that they appear neat and organized. The lids compartment ( 30 ) is configured to descend downward at a depth below the top plane ( 80 ). In addition, a user may place other miscellaneous items or kitchenware items in the square compartment ( 40 ). A user may place anything that needs to be stored, such as measuring cups, odd-shaped containers or square containers, in the square compartment ( 40 ). The square compartment ( 40 ) is configured to descend downward at a depth below the top plane ( 80 ).
[0016] FIG. 2 is a more detailed view of the present invention. In FIG. 2 , we see that the circular compartment ( 10 ), rectangular compartment ( 20 ), lids compartment ( 30 ) and square compartment ( 40 ) descend downward at a depth below the primary top plane ( 80 ) of the present invention. This depth functions so that the containers and lids may be organized and stacked by the user within an interior portion of the wired exterior ( 5 ). For example, FIG. 2 illustrates that the circular depth ( 60 ) permits a user to place circular containers beyond the top plane ( 80 ) of the circular compartment ( 10 ) in a neat and organized fashion that is compact. In addition, the rectangular depth ( 70 ) permits the user to place rectangular containers beyond the top plane ( 80 ) of the rectangular compartment ( 20 ) in a neat and organized fashion that is compact. The lids depth ( 85 ) permits the user to place lids beyond the top plane ( 80 ) of the lids compartment ( 30 ) in a neat and organized fashion that is compact. The square depth ( 90 ) permits the user to place miscellaneous items beyond the top plane ( 80 ) of the square compartment ( 40 ) in a neat and organized fashion that is compact. As we see in FIG. 2 , the user places the relevant containers, lids and miscellaneous items into the either the circular compartment ( 10 ), rectangular compartment ( 20 ), lids compartment ( 30 ) and square compartment ( 40 ) via either the circular depth ( 60 ), rectangular depth ( 70 ), lids depth ( 85 ) or square depth ( 90 ) for optimal organization and compactness.
[0017] It also is important to note that the front end ( 100 ) of the present invention in the preferred embodiment includes the rectangular compartment ( 20 ) and the square compartment ( 40 ). The rear end ( 110 ) of the present invention in the preferred embodiment includes the lids compartment ( 30 ) and the circular compartment ( 10 ). The lids compartment ( 30 ) and the circular compartment ( 10 ) at the respective lids depth ( 85 ) and circular depth ( 60 ) are much deeper and otherwise have more depth than the square compartment ( 40 ) and rectangular compartment ( 20 ) of the front end ( 100 ). This means that the front end ( 100 ) has less depth than the deeper rear end ( 110 ), which has more depth. This permits the user to place easily accessible objects underneath the front end ( 100 ) of the present invention.
[0018] FIG. 2 also shows that the present invention includes at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ). The preferred embodiment also adds at least two slideable tracks ( 85 ). The at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) are such so that a user can adjust the height of the storage system. The at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) are telescoping in the preferred embodiment. This is important because users often have different needs for storing other kitchen items such as trays and pans. In addition, users have very different amounts of cabinet space. The at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) when deployed to a higher level permit more storage of other items below the storage system of the present invention. For those with shorter cabinets, the at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) can be retracted to a shorter level to the point where the storage system is close to or touching the bottom of the cabinet. In this way, a user may adapt the present invention to meet the confines of a cabinet or cupboard while maintaining organization in an aesthetic quality. In addition, the user may adjust the height of the at least one front retractable leg ( 50 ) so that the at least one rear retractable leg ( 55 ) are higher. This permits the user to better reach into the cabinet and grab items stored in the rear end of the present invention. FIG. 2 depicts a view of the present invention where a user has deployed the at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) to ultimately raise the height of the wired exterior ( 5 ) and its circular compartment ( 10 ), rectangular compartment ( 20 ), lids compartment ( 30 ) and square compartment ( 40 ) via the circular depth ( 60 ), rectangular depth ( 70 ), lids depth ( 85 ) and square depth ( 90 ). FIG. 3 depicts a view of the present invention where a user has retracted the at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) to lower toward the bottom of the cabinet the wired exterior ( 5 ) and its circular compartment ( 10 ), rectangular compartment ( 20 ), lids compartment ( 30 ) and square compartment ( 40 ) via the circular depth ( 60 ), rectangular depth ( 70 ), lids depth ( 85 ) and square depth ( 90 ).
[0019] The at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) are secured to the wired exterior ( 5 ) via conventional means. A user may adjust the at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) to determine the deployed height or retracted height. The user adjusts the at least two retractable legs via an adjustment mechanism, which is conventional. The preferred embodiment of the adjustment mechanism includes a button that when compressed allows the user to adjust the height of each of the at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) at set increments to maintain easy coordination. However, an additional embodiment also allows the user to adjust the height of the at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) through the use of a fulcrum and lever controlled by the adjustment mechanism so that when the user compresses the adjustment mechanism, all of the at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) will adjust in concert with each other.
[0020] It also is envisioned that users may elect to slide the present invention in and out of the cabinet via the at least two tracks ( 95 ). In this case, the depiction in FIG. 3 is likely the most proper course of action as the user would fully retract the at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ). The wired exterior ( 5 ) is secured to the at least two tracks ( 95 ) and the at least two tracks ( 95 ) may be secured to the sides of the cabinets via conventional means. The preferred embodiment of the at least two tracks ( 95 ) includes conventional rollers so that the user may seamlessly slide the present invention in and out of the cabinet.
[0021] The user also may collapse the present invention in an additional embodiment. When the system of the present invention is collapsed, it is essentially formed into a more compact item that can be washed in the dishwasher or stowed for moving. In addition, this embodiment enables the user to collapse portions of the wired exterior ( 5 ) and its circular compartment ( 10 ), rectangular compartment ( 20 ), lids compartment ( 30 ) and square compartment ( 40 ) via the circular depth ( 60 ), rectangular depth ( 70 ), lids depth ( 85 ) and square depth ( 90 ). While the user collapses the present invention, the user also fully retracts the at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ). It is envisioned that this additional embodiment allows the user to collapse the wired exterior ( 5 ) of the present invention through a collapsing mechanism such that each wire of the wired exterior ( 5 ) is slideably engaged with one another so that the depth of the circular depth ( 60 ), rectangular depth ( 70 ), lids depth ( 85 ) and square depth ( 90 ) can be altered. It is important to note that this embodiment, beyond complete collapsing of the present invention, also permits the user to alter the depth of various quadrants of the storage system to cater to the user's needs. By sliding the wired exterior ( 5 ) of the storage system, the user can collapse its circular compartment ( 10 ), rectangular compartment ( 20 ), lids compartment ( 30 ) and square compartment ( 40 ) in order to alter the depth of those areas.
[0022] The present invention is a storage system. The user handles the system of the present invention by stacking at least one circular container into a circular compartment ( 10 ), the circular compartment ( 10 ) having a depth below a top plane ( 80 ). The user also stacks at least one rectangular container into a rectangular compartment ( 20 ), the rectangular compartment ( 20 ) having a depth below the top plane ( 80 ). The user also condenses at least one lid into a lids compartment ( 30 ), the lids compartment ( 30 ) having a depth below the top plane ( 85 ). The user places at least one kitchenware item into a square compartment ( 40 ), the square compartment ( 40 ) having a depth below the top plane ( 80 ). It also is important to note that the circular compartment ( 10 ), the rectangular compartment ( 20 ), the lids compartment ( 30 ) and the square compartment ( 40 ) are placed in a wired exterior ( 5 ). The user also can adjust at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ), the at least one front retractable leg ( 50 ) and at least one rear retractable leg ( 55 ) disposed on the wired exterior ( 5 ). The wired exterior ( 5 ) is organized such that the rectangular compartment ( 20 ) and the square compartment ( 40 ) make up a front end ( 100 ). The wired exterior ( 5 ) also is organized such that the lids compartment ( 30 ) and the circular compartment ( 10 ) make up a rear end ( 110 ). The circular compartment ( 10 ) is formed to have a radius equal to a depth of the lids compartment ( 30 ). The rectangular compartment ( 20 ) is formed to have a depth equal to the square compartment ( 40 ). The circular compartment ( 10 ) and the lids compartment ( 30 ) are disposed such that the circular compartment ( 10 ) and the lids compartment ( 30 ) extend at a depth below the rectangular compartment ( 20 ) and the square compartment ( 40 ). Meanwhile, the user may adjust the height of the at least one front retractable leg ( 50 ) and the at least one rear retractable leg ( 55 ). The user also may angle the wired exterior ( 5 ) by disposing the front end ( 100 ) at a lower height than the rear end ( 110 ). This is done by adjusting the at least one front retractable front leg ( 50 ) at a lower height than the at least one rear retractable leg ( 55 ). In the alternative embodiment, the wired exterior ( 5 ) may be mounted to at least two tracks ( 95 ). The wired exterior ( 5 ) then can slide along the at least two tracks ( 95 ). This is conventional and likely would work with a conventional track associated with the interior of the cabinet. Based on the depth relating to the front end ( 100 ) and the rear end ( 110 ), the user can store items underneath the front end ( 100 ).
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A storage system for organizing containers and lids of varying sizes, depths and shapes through the use of compartments. The compartments are configured in a variety of practical dimensions such as square, circular and rectangular. Retractable legs and sliding tracks offer additional storage capability and adaptability for users dealing with limited kitchen and cabinet space. The storage system also is collapsible for increased durability and this function—coupled with at least one front retractable leg and at least one rear retractable leg—allow the user to adjust such aspects as the height of the system. The containers and lids relating to the storage system are preferably of the plastic variety.
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RELATED APPLICATIONS
[0001] The present application is a Division of U.S. application Ser. No. 11/549,478, filed Oct. 13, 2006, which application claims the benefit of U.S. Provisional Application No. 60/726,887, filed Oct. 14, 2005, which applications are incorporated herein in their entirety by reference.
FIELD OF THE INVENTION
[0002] The invention relates to a device for material processing by means of laser radiation, said device comprising a source of laser radiation emitting pulsed laser radiation for interaction with the material; optics focusing the pulsed processing laser radiation to a center of interaction in the material; a scanning unit shifting the positions of the center of interaction within the material, wherein each processing laser pulse interacts with the material in a zone surrounding the center of interaction assigned to said laser pulse so that material is separated in the zones of interaction;
[0003] and a control unit which controls the scanning unit and the source of laser radiation such that a cut surface is produced in the material by sequential arrangement of zones of interaction.
BACKGROUND OF THE INVENTION
[0004] The invention further relates to a method of material processing by means of laser radiation, wherein pulsed processing laser radiation is generated, focused for interaction to centers of interaction in the material, and the positions of the centers of interaction in the material are shifted, wherein each processing laser pulse interacts with the material in a zone surrounding the center of interaction assigned to said laser pulse and material is separated in the zones of interaction and a cut surface is produced in the material by sequential arrangement of zones of interaction.
[0005] The invention further relates to a device for material processing by means of laser radiation, said device comprising a source of laser radiation emitting pulsed laser radiation for interaction with the material; optics focusing the pulsed processing laser radiation along an optical axis to a center of interaction in the material; a scanning unit shifting the positions of the center of interaction within the material, wherein each processing laser pulse interacts with the material in a zone surrounding the center of interaction assigned to said laser pulse so that material is separated in the zones of interaction; and a control unit which controls the scanning unit and the source of laser radiation such that a cut surface is produced in the material by sequential arrangement of zones of interaction.
[0006] The invention still further relates to a method of material processing by means of laser radiation, wherein pulsed processing laser radiation is generated and focused for interaction to centers of interaction in the material along an optical axis, and the positions of the centers of interaction in the material are shifted, wherein each processing laser pulse interacts with the material in a zone surrounding the center of interaction assigned to said laser pulse, and material is separated in the zones of interaction, and a cut surface is produced in the material by sequential arrangement of zones of interaction.
[0007] These devices as well as corresponding methods of material processing are particularly suitable to produce curved cut surfaces within a transparent material. Curved cut surfaces are produced, for example, in laser-surgical methods and, in particular, in ophthalmic operations. In doing so, treatment laser radiation is focused into the tissue, i.e. below the surface of the tissue, to a center of interaction. Material layers in a surrounding zone of interaction are separated thereby. The zone usually corresponds to the focus spot. The laser pulse energy is usually selected such that an optical breakthrough in the tissue forms in the zone of interaction.
[0008] In the tissue, a plurality of processes initiated by the laser radiation pulse take place in a time sequence after an optical breakthrough. First, the optical breakthrough generates a plasma bubble in the material. Once such plasma bubble has formed, it grows due to expanding gas. Next, the gas generated in the plasma bubble is absorbed by the surrounding material and the bubble disappears again. However, this process takes very much longer than the forming of the bubble itself. If a plasma is generated at a material interface which may even be located within a material structure, material removal is effected from said interface. This is then referred to as photoablation. In case of a plasma bubble separating previously connected material layers, one usually speaks of photodisruption. For the sake of simplicity, all such processes are summarized here by the term “interaction”, i.e. this term includes not only the optical breakthrough, but also any other material-separating effects.
[0009] For high precision of a laser-surgical method, it is indispensable to ensure high localization of the effect of laser beams and to avoid, if possible, collateral damage to adjacent tissue. Therefore, it is common in the prior art to apply the laser radiation in pulsed form so that the threshold value for the energy density required to initiate an optical breakthrough is exceeded only in the individual pulses. In this respect, U.S. Pat. No. 5,984,916 clearly shows that the spatial extent of the zone of interaction substantially depends on the pulse duration only as long as a pulse duration of 2 ps is exceeded. For values of few 100 fs, the size of the zone of interaction is almost independent of the pulse duration. Thus, high focusing of the laser beam in combination with very short pulses, i.e. below 1 ps, allows the zone of interaction to be inserted in a material with pinpoint accuracy.
[0010] The use of such pulsed laser radiation has recently become established, in particular, for laser-surgical correction of visual deficiencies in ophthalmology. Visual deficiencies of the eye are often due to the fact that the refractive properties of the cornea and of the lens do not cause optimal focusing on the retina. This type of pulsing is also the subject matter of the invention described herein.
[0011] The aforementioned U.S. Pat. No. 5,984,916 describes a method of producing a cut surface by suitably generating optical breakthroughs, thereby ultimately exerting a selective influence on the diffractive properties of the cornea. A multiplicity of optical breakthroughs are sequentially arranged such that the cut surface isolates a lens-shaped partial volume within the cornea of the eye. The lens-shaped partial volume separated from the remaining corneal tissue is then removed from the cornea via a laterally opening cut. The shape of the partial volume is selected such that upon removal the shape and, thus, the refractive properties of the cornea are changed so as to cause the desired correction of a visual deficiency. The cut surface required here is curved and circumscribes the partial volume, thus necessitating three-dimensional shifting of the focus. Therefore, two-dimensional deflection of the laser radiation is combined with simultaneous shifting of the focus in a third spatial direction. This is summarized here by the terms “scanning”, “shifting” or “deflecting”.
[0012] When composing the cut surface by sequential arrangement of optical breakthroughs in the material, an optical breakthrough is generated many times faster than the time it takes until a plasma generated thereby is absorbed by the tissue again. It is known from the publication of A. Heisterkamp et al., Der Ophthalmologe, 2001, 98:623-628, that, after an optical breakthrough has been generated, a plasma bubble forms in the eye's cornea at the focal point where the optical breakthrough was generated, which plasma bubble can grow together with adjacent bubbles to form macrobubbles. The publication explains that the joining of still growing plasma bubbles reduces the quality of the cut. Therefore, said publication proposes a method wherein individual plasma bubbles are not generated immediately adjacent to each other. Instead, a gap is left in a spiral-shaped profile between sequentially generated optical breakthroughs, which gap is filled with optical breakthroughs and the resulting plasma bubbles in a second pass through the spiral. This is intended to prevent joining of adjacent plasma bubbles and to improve the quality of the cut.
[0013] In order to achieve good quality of the cut, the prior art thus uses defined sequences in which the optical breakthroughs are generated. This is intended to prevent joining of growing plasma bubbles. Since a cut is desired, of course, wherein as few bridges as possible connect the material or the tissue, respectively, the plasma bubbles generated ultimately have to grow together in any case to form a cut surface. Otherwise, the material connections would remain and the cut would be incomplete.
[0014] Therefore, it is an object of the invention to generate good-quality cuts in the material without having to observe defined sequences when introducing laser pulses.
[0015] According to the invention, this object is achieved in a first variant by a device of the first-mentioned generic type, wherein the control unit controls the source of laser radiation and the scanning unit such that adjacent centers of interaction are located at a spatial distance a ≦10 μm from each other. In the first variant, the object is further achieved by a method of the first-mentioned generic type, wherein adjacent centers of interaction are located at a spatial distance a ≦10 μm.
[0016] In a second variant of the invention, the object is achieved by a device of the first-mentioned generic type, wherein the fluence F of the pulses for each center of interaction is respectively below 5 J/cm 2 . In the second variant, the object is also achieved by a method of the first-mentioned generic type, wherein the zones of interaction are exposed to pulses whose fluence F is respectively below 5 J/cm 2 .
[0017] In a third variant of the invention, the object is achieved by a device of the second-mentioned generic type, wherein the control unit controls the source of laser radiation and the scanning unit such that the cut surface comprises two portions located adjacent to each other along the optical axis, and at least partially illuminates them with laser pulses applied within a time interval t≦5 s. Also in the third variant the object is achieved by a method of the second-mentioned type, wherein the cut surface comprises two portions located adjacent to each other along the optical axis which are at least partially exposed to laser pulses applied within a time interval t≦5 s.
[0018] The invention is based on the finding that zones of interaction in the material influence each other. Thus, the effect of a laser beam pulse depends on the extent to which previous laser exposures already took place in the vicinity of the center of interaction. From this, the inventors concluded that the pulse energy required to generate an optical breakthrough or to cause material separation depends on the distance from the nearest center of interaction. All of the variants according to the invention take advantage of this finding.
[0019] The inventive minimization of the distance between centers of interaction, e.g. of the distance between the focus positions of adjacent optical breakthroughs, according to variant 1 allows the processing pulse energy to be decreased. The parameter describing the pulse energy is the fluence, i. e. the energy per area or the areal density of energy. Thus, the inventive variant 1 with a distance of less than 10 μm addresses an aspect of the finding attributable for the first time to the inventors.
[0020] Another aspect is that the fluence of the processing laser pulses is now significantly reduced. Thus, variant 2 relates to the same aspect as variant 1 , although it does not prescribe an upper limit for the distance, but for the fluence.
[0021] Accordingly, all variants of the invention provide basic conditions for producing a cut by introducing pulsed laser radiation, said basic conditions taking into consideration the effects of the immediately adjacent introduced pulse. Regarding the pulse length, the teaching of U.S. Pat. No. 5,984,916 is applied here, i.e. pulses below 1 ps, preferably few 100 fs, e. g. 300-500 fs, are used. As far as the invention defines an upper limit of the distance, this refers to the distance from the closest center of interaction. Since a cut surface is usually produced by a multiplicity of sequentially arranged centers of interaction, the distance may be understood, for the sake of simplicity, also to be the mean value of the laser focus spacing for the laser pulses in the material. If the grating of centers of interaction which is substantially two-dimensional along a cut surface is not symmetrical, distance can also be the characteristic mean spacing. It is known in the prior art to use a pulsed source of laser radiation and to modify some of the laser pulses emitted by said source such that they do not cause a processing effect in the material. Only some of the laser radiation pulses will then be used for processing. Whenever the present description uses the term “laser radiation pulse”, “laser pulse” or “pulse”, this always means a processing laser pulse, i.e. a laser radiation pulse provided or formed or suitable for interaction with the material.
[0022] The complexity of equipment is reduced by the invention, because the pulse peak performance decreases. Due to the reduced distance of the centers of interaction, the pulse repetition frequency increases if the processing duration is to be kept constant. Further, smaller plasma bubbles are produced in the case of optical breakthroughs, thus making the cut thinner. However, the prior art always worked with comparatively large distances between the centers of interaction and the fluence of the pulses was selected suitably high in order to securely obtain optical breakthroughs and large plasma bubbles suitably adapted to the distances.
[0023] At the same time, a lower fluence also reduces personnel hazards during material processing. This is of essential importance in ophthalmic methods. It turns out to be particularly advantageous that it is now possible to work with lasers of hazard class 1M, whereas class 3 was required in the prior art. This class required operating personnel, for example a physician or a nurse, to wear protective goggles, which naturally makes patients feel uneasy. Such protective measures are no longer necessary with the lasers of class 1M that are now possible according to the invention.
[0024] Therefore, the invention also provides as a further embodiment, or independently, a device for material processing by means of laser radiation, said device comprising an emitting source of laser radiation which emits pulsed laser radiation for interaction with the material, optics focusing the pulsed laser radiation to a center of interaction in the material, a scanning unit shifting the position of the center of interaction in the material, wherein each processing laser pulse interacts with the material in a zone surrounding the center of interaction assigned to said pulse, so that material is separated in the zones of interaction, and said device further comprising a control unit controlling the scanning unit and the source of laser radiation such that a cut surface is produced in the material by sequential arrangement of zones of interaction, wherein a laser of a hazard class below 3, preferably a laser of hazard class 1M, is employed. The indication of the hazard class relates to International Standard IEC 60825-1 in its version as effective Oct. 13, 2005. Analogously, there is provided (independently or as a further embodiment) a device for material processing by means of laser radiation, said device comprising a source of laser radiation emitting pulsed laser radiation for interaction with the material; optics focusing the pulsed laser radiation to a center of interaction in the material along an optical axis; a scanning unit shifting the position of the center of interaction in the material, each laser pulse interacting with the material in a zone surrounding the centers of interaction assigned to said pulse and material being separated in the zones of interaction, said device further comprising a control unit controlling the scanning unit and the source of laser radiation such that a cut surface is produced in the material by sequential arrangement of zones of interaction, wherein a laser of a hazard class below 3, preferably a laser of hazard class 1M, is used. This is also useful as a further embodiment for each of the aforementioned devices or for each of the aforementioned methods, respectively. Unless explicitly indicated otherwise, this shall apply to each described advantageous design, further embodiment or realization.
[0025] Tests carried out by the inventors have shown that an optical breakthrough sets in only above a defined threshold value M which is a function of the distance a of adjacent centers of interaction according to the equation M=3.3 J/cm 2 −(2.4 J/cm 2 )/(1+(a/r 2 ) 2 ). An optical breakthrough is ensured for each individual laser pulse only at a pulse fluence above the threshold value M. The parameter r appearing in said equation represents an experimentally recognized average range of the influence of adjacent zones of interaction. Depending on the application, there may be fluctuations here, so that a variation of the value between 3 and 10 μm is possible; preferably, r=5 μm.
[0026] In a further embodiment of the invention, the upper limit of pulse fluence mentioned for variant 2 of the invention will also be based on the aforementioned dependence of the threshold value on the distance of adjacent centers of interaction. Therefore, a further embodiment is preferred in which fluence exceeds the threshold value M by an excessive energy of no more than 3 J/cm 2 . The range defined thereby provides a particularly good quality of the cut, while initiation of an optical breakthrough is ensured at the same time. If the excessive energy were further increased, unnecessarily large plasma bubbles would be generated and the quality of the cut would deteriorate.
[0027] However, producing a cut now no longer stringently requires working with optical breakthroughs. The inventors have found that, if the zones of interaction overlap, material can be separated and, thus, a cut surface can be formed even at energies of the pulsed laser radiation below a threshold value for initiation of an optical breakthrough. Therefore, a further embodiment is provided wherein the spatial distance a of the centers of interaction of two sequential pulses is smaller than the size of the focus d, so that there is a mutual overlap of volumes of the material that are sequentially irradiated with laser radiation, i.e. zones of interaction. This embodiment results in material separation without formation of plasma bubbles, which leads to a particularly smooth cut.
[0028] Advantageously, the fluence of the laser pulse can then also be decreased below the already explained threshold value, because a tissue-separating effect is still achieved due to overlapping of zones of interaction. The individual laser pulse then no longer securely generates an optical breakthrough; the separation of tissue is caused only if the zones of interaction overlap. This allows pulse energies that are orders of magnitude below those of the state of the art; at the same time the quality of the cut is increased again, because zones of interaction, which are generated sequentially in time, overlap. Thus, the distance of the centers of interaction ranges from zero to the diameter of the focus, which is e.g. between 1 and 5 μm considering the 1/e 2 diameter (e=Euler's constant).
[0029] Cutting according to the invention produces a very fine cut because, due to the reduced distance or the reduced pulse energy, respectively, correspondingly small or even no plasma bubbles are worked with or can be worked with. However, a fine cut surface can also be a disadvantage, e.g. if a surgeon wants to optically recognize at least part of the cut surface. This is the case, for example, in laser surgery according to the fs-LASIK method. The partial volume isolated therein by the action of laser radiation, which volume is to be removed from the tissue by a lateral cut, is usually freed first from any residual bridges to the surrounding material by the surgeon using a spatula. For this purpose, the surgeon pushes the spatula into the pocket formed by the laterally opening cut and traces the partial volume with the spatula. In case of a very fine, i.e. smooth cut surface, it may occur that the surgeon can no longer see the profile of the cut surface in the material from outside. Therefore, he will not know where the periphery of the partial volume lies and will not be able to securely guide the spatula. In order to solve these problems, a method of the above-mentioned type is provided wherein the cut surface is divided into at least two partial surfaces, and one partial surface is formed with operating parameters that generate a coarser and, thus, rougher cut surface. In a device of the above-mentioned type, the control unit carries out the corresponding control of the laser source and of the scanning unit. Preferably, said coarser cut surface will be placed on the periphery, which is easily recognizable for the user and is of no importance to the quality of the cut surface, e.g. in ophthalmic surgery. Thus, the two partial surfaces differ from each other with respect to at least one parameter influencing the fineness of the cut surface. For instance, a possible parameter is the fluence of the laser pulses used or the spatial distance between the centers of interaction.
[0030] Combining this approach, which may be principally effected in different ways and is not restricted to the invention described herein, with one of the aforementioned variants of the invention, it is convenient for the control unit to control the source of laser radiation and the scanning unit such that the cut surface is composed of at least a first and a second partial cut surface, the first partial cut surface being produced by controlling the source of laser radiation and the scanning unit according to one of the aforementioned inventive concepts, and the second partial cut surface being produced by controlling the source of laser radiation so as to cause a pulse fluence of more than 3 J/cm 2 , preferably more than 5 J/cm 2 . Of course, a >10 μm may be set then, because the plasma bubbles will be large. The latter partial surface then automatically has the desired coarser structure and facilitates recognition of the cut surface by the user or surgeon. The analogous method accordingly provides for the second partial cut surface to be produced by a method of the invention at a pulse fluence of more than 3 J/cm 2 , preferably more than 5 J/cm 2 .
[0031] Conveniently, the coarser partial surface will be selected such that it surrounds the finer partial surface, so that the surgeon can clearly recognize the periphery of the cut surface and optical imaging at the treated eye (in the case of ophthalmic surgery) is not adversely affected. The finding upon which the invention is based further shows that the threshold value required to securely achieve an optical breakthrough decreases as the distance of the centers of interaction decreases.
[0032] The analysis carried out by the inventors further shows that the shape of the plasma bubbles generated, which are formed as a result of the interaction of the laser pulses with the material or the tissue, respectively, can be subject to a temporal change, as also indicated in the publication by Heisterkamp et al. However, whereas this publication focuses on preventing a center of interaction from being located near a just growing plasma bubble, it is now the object of variant 3 of the invention that a deformation generated by a macrobubble will not affect the quality of the cut. If a further optical breakthrough were placed at a defined position in deformed material or tissue, the position of the center of interaction within the material or tissue would be shifted as soon as said deformation is reduced by relaxation. Therefore, it is envisaged according to the third variant to keep the time between the application of laser energy in two areas of the material or of the tissue, respectively, influencing each other so small that it is smaller than a characteristic time for forming of macrobubbles. Said time is approximately 5 s. Of course, this approach is required only if two portions of the cut surface located adjacent to each other along the optical axis are present, because only then can a deformation caused by producing a cut surface portion have an effect on the formation of the other cut surface portion which is located adjacent thereto along the optical axis.
[0033] This approach is particularly important in generating a partial volume during the fs-LASIK method. This partial volume, also referred to as a lenticule, is generated by a posterior portion and an anterior portion of the cut surface, so that the cut surface as a whole circumscribes the lenticule. However, generating the posterior and anterior portions together within the characteristic time for forming the macrobubbles may result in relatively high demands on the scanning unit's speed of deflection or inevitably leads to special scanning paths. Preferably, this can be avoided by dividing the posterior and anterior portions into partial surfaces and skillfully selecting the processing sequence of these partial surfaces.
[0034] In one embodiment, the two areas are subdivided into annular partial surfaces. Since in the case of a lenticule the central partial surface has a much stronger influence on optical quality than the peripheral regions, first the cut corresponding to the central partial surface of the posterior portion and then that of the anterior portion is produced, so that the partial surfaces are formed immediately after each other. Then, the annular partial surface of the posterior portion, and that of the anterior portion is cut next. This principle can also be carried out with as many partial surfaces as desired. Practical limits are given by the fact that switching between the anterior and posterior portions always requires shifting of the laser focus along the optical axis, which for technical reasons takes up most of the time during scanning
[0035] With this approach, it is important to note that the diameter of each annular or circular posterior partial surface should be somewhat larger than the diameter of the respective anterior partial surface generated next. This ensures that the posterior partial cut to be produced next makes not only anteriorly located disruption bubbles acting as centers of scattering impossible. The minimum amount by which the posterior partial cut has to be larger than its associated anterior partial cut is given by the numerical aperture of the focusing optics.
[0036] A further way of pushing the time interval below the characteristic time consists in generating the posterior portion with a spiral of the centers of interaction, said spiral extending from the outside to the inside, and in generating the anterior portion with a spiral extending from the inside to the outside. This ensures that portions located adjacent to each other along the optical axis are formed at least in the central region within the 5 s time interval. Of course, this method can be applied to the already mentioned divisions of partial surfaces.
[0037] It is therefore preferred that the control unit control the source of laser radiation as well as the scanning unit such that at least some of the portions adjacent to the optical axis are illuminated immediately subsequent to each other in time by sequential arrangement of the centers of interaction.
[0038] Analogous considerations also apply to the embodiment of the method according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The invention will be explained in more detail below, by way of example and with reference to the Figures, wherein:
[0040] FIG. 1 shows a laser surgical instrument for eye treatment;
[0041] FIG. 2 shows a diagram of the effect of laser radiation on the cornea of the eye for the instrument of FIG. 1 ;
[0042] FIG. 3 shows a schematic view illustrating how a partial volume is generated and isolated by the instrument of FIG. 1 ;
[0043] FIG. 4 shows a deflecting device of the instrument of FIG. 1 ;
[0044] FIG. 5 shows a block diagram illustrating the structure of the instrument of FIG. 1 ;
[0045] FIG. 6 shows a relationship between the distance of the centers of the optical breakthroughs generated by the instrument of FIG. 1 and the pulse energy, wherein possible operating ranges for the instruments of FIG. 1 are illustrated;
[0046] FIG. 7 shows a representation similar to that of FIG. 6 ;
[0047] FIG. 8 shows a schematic top view of the eye's cornea for clearer illustration of the generated plasma bubbles' position or the cut surface caused thereby, respectively;
[0048] FIG. 9 shows a sectional view of the representation of FIG. 8 along the line A 1 -A 1 ;
[0049] FIG. 10 shows a schematic view illustrating the arrangement of a plurality of zones of interaction when producing the cut surface with an instrument according to FIG. 1 , and
[0050] FIGS. 11 and 12 show views similar to that of FIG. 10 for modified modes of operation.
DETAILED DESCRIPTION
[0051] FIG. 1 shows a laser surgical instrument for treatment of a patient's eye 1 , said laser surgical instrument 2 serving to effect a refractive correction. For this purpose, the instrument 2 emits a treatment laser beam 3 onto the eye of the patient 1 whose head is fixed in a head holder 4 . The laser surgical instrument 2 is capable of generating a pulsed laser beam 3 such that the method described in U.S. Pat. No. 5,984,916 can be carried out. For example, the treatment laser beam 3 consists of fs-laser pulses having a pulse repetition rate of between 10 and 500 kHz. In the exemplary embodiment, the structural components of the instrument 2 are controlled by an integrated control unit.
[0052] As schematically shown in FIG. 2 , the laser surgical instrument 2 comprises a source of radiation S whose radiation is focused into the cornea 5 of the eye 1 . Using the laser surgical instrument 2 a visual deficiency of the patient's eye 1 is corrected by removing material from the cornea 5 such that the refractive properties of the cornea change to a desired extent. In doing so, said material is removed from the corneal stroma which is located below the epithelium and the Bowman membrane as well as above the Decemet membrane and the endothelium.
[0053] Material removal is effected by separating material layers in the cornea using an adjustable telescope 6 to focus the high-enery pulsed laser beam 3 to a focus 7 located in the cornea 5 . Each pulse of the pulsed laser radiation 3 generates an optical breakthrough in the tissue, such optical breakthrough in turn initiating a plasma bubble 8 . Thus, the tissue layer separation covers a larger area than the focus 7 of the laser radiation 3 , although the conditions for achieving the breakthrough are achieved only in the focus 7 . Then, many plasma bubbles 8 are generated by suitable deflection of the laser beam 3 during treatment. This is shown schematically in FIG. 3 . The plasma bubbles then form a cut surface 9 which circumscribes a partial volume T of the stroma, namely the material to be removed from the cornea 5 . The cut surface 9 is formed by sequential arrangement of the plasma bubbles 8 as a result of a continuous shift in the focus 7 of the pulsed laser beam 3 .
[0054] Due to the laser radiation 3 the laser surgical instrument 2 acts like a surgical knife directly separating material layers within the cornea 5 without damaging the surface of the cornea 5 . If a cut 16 is guided up to the surface of the cornea by further generation of plasma bubbles 8 , material of the cornea 5 isolated by the cut surface 9 can be pulled out laterally in the direction of the arrow 17 and can thus be removed.
[0055] On the one hand, displacement of the focus is then effected in the embodiment by means of the deflecting unit 10 shown schematically in FIG. 4 , said deflecting unit 10 deflecting the laser beam 3 , incident on an optical axis H of the eye 1 , about two mutually orthogonal axes. For this purpose, the deflecting unit 10 uses a line mirror 11 as well as a frame mirror 12 , which leads to two spatial axes of deflection located behind each other. The point of intersection of the optical axis H and the deflecting axis is then the respective point of deflection. On the other hand, the telesecope 6 is suitably adjusted for focus displacement. This allows the focus 7 to be shifted along three orthogonal axes in the x/y/z coordinate system shown schematically in FIG. 4 . The deflecting unit 10 shifts the focus in the x/y plane, with the line mirror allowing to shift the focus in the x direction and the frame mirror allowing a shift in the y direction. In contrast thereto, the telescope 6 acts on the z coordinate of the focus 7 . Thus, three-dimensional displacement of the focus 7 is achieved as a whole.
[0056] Due to the corneal curvature which is between 7 and 10 mm the partial volume T also has to be curved accordingly. Thus, the corneal curvature requires a curved cutting plane. This is effected by suitable control of the deflecting unit 10 and of the telescope 6 .
[0057] FIG. 5 shows a simplified block diagram of the laser surgical instrument 2 for refractive surgery on the human eye 1 . Only the most important structural components are shown: an fs laser serving as source of radiation S, which laser consists of an fs oscillator V as well as of one or more amplifying stages 13 and following which a compressor or pre-compressor 14 is arranged here as well; a laser pulse modulator 15 on which laser radiation from the laser S is incident; the deflecting unit 10 , realized as a scanner here; an objective for focusing into the tissue to be treated, said objective realizing the telescope 6 , and the control unit 17 .
[0058] The laser S generates laser pulses having a duration in the fs range. First, the laser pulses reach the laser pulse modulator 15 which influences the laser pulses (in a manner yet to be described) according to a control signal from the control unit 17 . Next, at least the treatment laser pulses reach the scanner 10 and pass through the objective 6 into the patient's eye 1 . There, they are focused and generate optical breakthroughs in the focus 7 . The modulator sets the energy of the laser pulses, i.e. the fluence of the individual laser pulses. As the modulator an AOM or an electro-optical modulator (EOM), a Pockels cell, a liquid crystal element (LC element), a fiber-optical switching element or a variable attenuator, e.g. a neutral density filter, may be used.
[0059] The laser surgical instrument 1 can then work in different modes of operation which may each be realized separately or in combination and which relate to the energy or the fluence F of each laser pulse or to the local distance at which the laser pulses are sequentially arranged so as to generate the cut surface 9 .
[0060] FIG. 6 shows a threshold value M as a graph illustrating the relationship between a spacing a at which the centers of interaction of the individual laser pulses are sequentially arranged within the eye's cornea 5 and the fluence F of each laser pulse. An optical breakthrough with an ensuing plasma bubble is generated only at a fluence above the threshold value.
[0061] The circles entered into the graph result from experimental measurements and represent points of measurement. Measurement was effected at a pulse duration of 300 fs and a 3 μm spot diameter of the focus 7 .
[0062] The instrument 1 may be operated in an operational range 18 according to FIG. 6 which may be defined by various boundary conditions. The different definitions correspond to different variants of the invention. All variants are based on the course of the threshold value M for the fluence F as a function of the distance a. This dependence is approximated by the following formula: M=3.3 J/cm 2 −(2.4 J/cm 2 )/(1+(a/r 2 ) 2 ), wherein r is a parameter representing the average range of influence and is located between 3 and 10 μm, preferably 5 μm.
[0063] In a first variant, the instrument 1 works with a spacing a of the laser focuses 7 , i. e. of the centers of interaction, which is below a maximum value amax=10 μm. From this value, the graph for the threshold value M drops considerably towards smaller spacings a, making it possible to work with a clearly reduced fluence F.
[0064] In a second variant, an upper limit Fmax is employed for the fluence F. The value for this is 5 J/cm 2 .
[0065] In a combination of the first and second variants, both a≦amax and F≦Fmax apply. The spacings of the centers of interaction as well as the fluence of the laser pulses are located within the region composed of partial areas 18 . 1 and 18 . 2 which are yet to be explained. Since the laser surgical instrument 1 , in both variants per se as well as in the combination of these two variants, respectively generates optical breakthroughs in the material, e.g. the cornea 5 , the fluence F is, of course, always above the threshold value M, because each laser pulse securely generates an optical breakthrough 8 only above said threshold value.
[0066] A third variant modifies the second variant such that the fluence F of each laser pulse only exceeds the threshold value M at the most by an excessive energy of between 3 and 3.5 J/cm 2 . The fluence F is then kept below the dotted line of FIG. 6 which separates the areas 18 . 1 and 18 . 2 from each other. Of course, the third variant can also be combined with the first variant, so that the fluence F and the spacing a are located in the hatched area 18 . 2 .
[0067] In a different embodiment, the laser surgical instrument 1 works with laser pulses of which not every single one securely generates an optical breakthrough 8 . However, in order to achieve material separation in spite of this, the centers of interaction are sequentially arranged at a spacing a which is smaller than the diameter d of the laser focus, i.e. smaller than the size of the zones of interaction. This mode of operation is shown in more detail in FIGS. 10-12 .
[0068] FIG. 10 shows a one-dimensional example of the arrangement of the centers of interaction Z corresponding to the position of the (theoretical) focal point. Each interaction is generated by a laser pulse, with the focus 7 being diffraction-limited, for example, and having the diameter d of 3 μm, for example, as assumed in FIG. 7 . The centers of interaction, i.e. the center of the focused laser radiation, are then displaced such that adjacently covered zones of interaction 20 , 21 , 23 and 24 respectively overlap with their immediate neighbors. Thus, there are overlapping regions 25 , 26 , 27 , which are each covered by two zones of interaction. The energy introduced into a zone of interaction is below the threshold value M, so that each of the zones of interaction 20 - 24 per se does not securely cause an optical breakthrough. However, due to said overlapping a material-separating effect is still achieved. Thus, it is essential for this mode of operation that the distance between the coordinates of the centers of interaction is smaller than the extent d of the zones of interaction. FIG. 10 clearly shows that the distance between the individual coordinates X 1 , X 2 , X 3 and X 4 corresponds to approximately half the diameter d of the zones of interaction 20 - 24 , which results in a simple overlap.
[0069] FIG. 11 shows a narrower graduation of the zones of interaction, ultimately resulting in a four-fold overlap of the zones of interaction. This allows a further reduction of the fluence F.
[0070] FIG. 12 illustrates that the representations of FIGS. 10 and 11 are only one-dimensional, i.e. considering only the x coordinate, for the sake of simplicity. If the zones of interaction overlapping each other in the x direction are displaced in the y direction, further overlaps will be achieved, so that in spite of the actually just one overlap in the x direction a three- or five-fold overlap of zones of interaction is achieved in the y direction, depending on the intervals. In this case, the selection of the intervals in the x direction or in the y direction, respectively, allows any desired factors of overlap ( 2 , 3 , 4 , 5 , 6 , 7 , . . . ).
[0071] As a result, the instrument 1 works in the operating range 19 , which is characterized in that the distance between two subsequent centers of interaction is smaller than the extent of the zones of interaction or than the size of the focus spot and in that the fluence F is below the threshold value M required to generate optical breakthroughs.
[0072] In practice, a spacing of the laser focuses or of the centers of interaction, respectively, of approximately 3-5 μm has turned out to be well-suited for generating high-quality cuts with as little pulse energy as possible and requiring a limited amount of time.
[0073] In a laser surgical instrument 1 which produces very fine cuts, e.g. if the above-described fluence values are used for the laser pulses, the cut is not visible even immediately upon being produced, either because plasma bubbles or gas bubbles appear, having a smaller size and a shorter life than during operation outside the region 18 , or because no bubbles form at all (during operation in the region 19 ). This may make it more difficult to prepare the isolated cut, e.g. by means of a spatula. A manual procedure used in many applications and wherein residual bridges which have not yet been fully separated are pierced by a spatula or other tools can become very difficult in case of such smooth cut.
[0074] In order to avoid this, the control device 17 of the laser surgical instrument 1 carries out the division of the cut shown in FIGS. 8 and 9 , for example. The cut surface is divided into partial cut surfaces having different degrees of fineness. These partial cut surfaces are cut with different smoothness so that regions form in which the cut surface has better optical visibility than in other regions.
[0075] FIG. 8 shows a top view of the cornea 5 of the patient's eye 1 , and FIG. 9 shows a sectional view along line A 1 -A 1 of FIG. 8 . As can be seen, the cut surface 9 is adapted to isolate the partial volume T, as already schematically indicated in FIG. 3 . The cut surface 9 then consists of an anterior portion F and a posterior portion L. The anterior portion F is guided up to a peripheral opening S via a laterally opening cut 16 leading up to the corneal surface. Thus, after forming the cut surface 9 the portions F, L, 16 and S of the lens-shaped partial volume T are located in a pocket formed by the peripheral opening S.
[0076] In order that a surgeon may feel this pocket with a spatula or other surgical instrument so as to sever possible bridges of tissue between the lens-shaped partial volume T and the rest of the cornea 5 , the anterior portion F as well as the posterior portion L are respectively divided into two partial regions. A core region F 1 or L 1 , which is substantially circular, is respectively surrounded by an annular peripheral region F 2 or L 2 . In the core region located near the optical axis of vision, a small size of plasma bubble, i.e. a fine line of cutting, is worked with. This may be effected, for example, by operation in the regions 18 or 19 of FIGS. 6 and 7 , respectively. In contrast thereto, a comparatively coarser cut is produced in the (annular) peripheral regions L 2 and F 2 , for example by deliberately working outside the regions 18 or 19 , so that relatively large plasma bubbles form. Thus, in these peripheral regions, the cut surface is a lot rougher and easier to recognize by the surgeon.
[0077] The diameters of the central regions F 1 and L 1 are preferably greater than the pupil diameter P of the treated eye. Thus, the peripheral regions F 2 and L 1 , where a rougher cut was employed, are located outside the region of the cornea 5 used for optical perception and accordingly do not have a disturbing effect. The purpose of dividing the portions L and F is to simultaneously achieve the aspect of maximum precision of cutting as well as of good handling due to the visibility of the cut in the peripheral region as a result of differences in processing.
[0078] If plasma bubbles are employed for material separation, the energy of the laser pulses is above the threshold value M. As already mentioned, the shape of the bubbles resulting from the absorption of the laser energy in the tissue is subject to change over time. A first phase in which individual bubbles form is followed by a phase of agglomeration in which several individual bubbles join to form larger macrobubbles. Finally, dissipation is noted as the last phase in which the gas content of the macrobubbles is absorbed by the surrounding tissue until the bubbles have finally vanished again completely. Now, macrobubbles have the adverse property of deforming the surrounding tissue. If a further center of interaction is placed at a certain position in the deformed tissue to form the beginning of a plasma bubble, the position of the center of interaction will change and so will the position of the tissue separation effected thereby as soon as the phase of dissipation begins, in which the bubbles disappear and the deformed tissue relaxes (at least partially). Since the macrobubbles form only after a characteristic time and are not present already upon introducing laser pulse energy, it is envisaged for one variant of the laser surgical instrument 1 that the time between application of the laser energy in two regions of the tissue potentially influencing each other be kept sufficiently short so as to be shorter than a characteristic time which is required to form macrobubbles.
[0079] During isolation of the lens-shaped partial volume T, regions of the posterior and anterior portions of the cut surface 9 having an adverse effect on each other are located in the region of the optical axis of vision. If the cut is produced in the anterior portion F of the cut surface 9 only at a time when the previously processed posterior portion L already comprises macrobubbles, the cut surface of the anterior portion F is located within deformed tissue. The result after relaxation would be an undesired undulation of the cut surface 9 in the anterior portion F. Therefore, the laser surgical instrument 1 produces the cut surface in the anterior portion F and in the posterior portion L within a time interval which is smaller than the characteristic time it takes for macrobubbles to form. Typically, such time is approximately 5 s.
[0080] One way of achieving this consists in dividing the anterior and posterior portions into corresponding partial surfaces and alternating between the partial surfaces of the posterior and anterior portions during production of the cut surface so that at least in the central region the characteristic time for producing partial surfaces, posteriorly and anteriorly, is not exceeded. A further possibility consists in a suitable sequential arrangement of the centers of interaction. Thus, for example, first the posterior portion L can be cut in a spiral leading towards the optical axis of vision from the outside to the inside and directly afterwards the anterior portion F can be cut in a spiral extending outwards from the axis of vision. The generated interactions, at least in a core region around the axis of vision, are then within the time frame given by the characteristic period of time so that there is no influence on the macrobubbles during processing of the anterior portion.
[0081] During division into the partial surfaces which the laser surgical instrument 1 effects under the control of the control device 17 it is ensured that a posterior region to be worked on is not disturbed by an already processed anterior surface or zone of interaction acting as a scattering center.
[0082] The described cut shapes, surface divisions, etc. are effected by the laser surgical instrument under the control of the control device 17 . The control device 17 causes operation of the laser surgical instrument 1 by the process features described herein.
[0083] As far as embodiments of the laser surgical instruments have been described above, they can be realized alone as well as in combination, depending on the specific realization of the laser surgical instrument 1 . Instead of being employed in laser surgery, the instrument 1 can also be used for non-surgical material processing, for example in the production of wave guides or the processing of flexible materials.
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A device for material processing by laser radiation, including a source of laser radiation emitting pulsed laser radiation for interaction with the material, optics focusing the pulsed processing laser radiation to a center of interaction in the material, and a scanning unit shifting the positions of the center of interaction within the material. Each processing laser pulse interacting with the material in a zone surrounding the center of interaction assigned to the laser pulse so that material is separated in the zones of interaction. A control unit controls the scanning unit and the source of laser radiation such that a cut surface is produced in the material by sequential arrangement of zones of interaction. The control unit controls the source of laser radiation and the scanning unit such that adjacent centers of interaction are located at a spatial distance a ≦10 μm from each other.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of copending U.S. patent application Ser. No. 12/140,862, filed Jun. 17, 2008, titled “Cardiomechanical Assessment for Cardiac Resynchronization Therapy.”
FIELD OF THE INVENTION
[0002] The present disclosure relates to an implantable sensor that is capable of measuring longitudinal, radial and torsional strain in the heart. The strain data can be used to improve cardiac resynchronization therapy timings for implantable cardiac stimulation devices and systems.
BACKGROUND
[0003] Implantable devices for pacing, cardioversion, defibrillation and resynchronization of cardiac electrical and mechanical function are widely available to prevent and treat arrhythmias and dysynchronous myocardial mechanics. These disorders can impair cardiac performance by altering electrical conduction patterns or by changing myocardial contractility or compliance, both of which result in mechanical dysfunction.
[0004] For example, conduction abnormalities may occur between the atria and the ventricular chambers. When atrio-ventricular (AV) timing is shortened, ventricular contraction may prematurely terminate the atrial kick produced by the contracting atrium. When AV timing is prolonged, increased ventricular loading from the atria may be lost due to regurgitation during prolonged diastole. Thus, both shortened and prolonged AV timing intervals can affect cardiac output.
[0005] Conduction abnormalities between right and left ventricular chambers (inter-ventricular) or within the right or left ventricles (intra-ventricular) can also result in dysynchrony. Dysynchrony occurs when forces generated in specific regions at inappropriate times cause bulging of the chamber walls into adjacent relaxed wall segments, or against prematurely closed heart valves. This lack of coordination during myocardial contraction may cause a reduction of forward blood flow and lead to reduced contractile efficiency.
[0006] Conduction abnormalities may also result in contractile and compliance abnormalities with cardiac function. For example, conduction delays may cause the left ventricular myocardium to continue to contract even after the closure of the aortic valve. This persistent contractile effect creates post-systolic wall thickening that can reduce left ventricle compliance and cause a reduction in ventricular end-diastolic volume (pre-load). The reduction in pre-load will reduce stroke volume and cardiac output through the Frank-Starling mechanism. Post-systolic wall thickening and post-systolic myocardial motion are also indicative of inefficient cardiac effort occurring against a closed aortic valve.
SUMMARY
[0007] The present disclosure relates to an implantable cardiomechanical sensor that is capable of measuring longitudinal, radial and torsional motion/deformation (e.g. strain and strain rate) in the heart. In some embodiments, these data can be used to improve cardiac resynchronization therapy timings for implantable cardiac stimulation devices and systems. For example, the time to peak strain in the septal and lateral regions of the myocardium can be compared to determine whether dysynchrony exists. If dysynchrony exists, interventricular timing and atrioventricular timing can be adjusted to reduce the level of dysynchrony. In other embodiments, the data can be used to detect a myocardial infarction.
[0008] In one aspect, the invention relates to an implantable cardiac stimulation device that includes a first lead adapted to be implanted in or on the heart of a patient. The first lead is adapted to provide therapeutic stimulation to the heart of the patient and includes a first mechanical sensor that obtains measurements indicative of the physical contraction and relaxation of the walls of the heart during systole and diastole. The device also includes a controller that induces a delivery of therapeutic stimulation to the heart of the patient via the first lead. The controller receives signals from the first mechanical sensor indicative of the contraction and relaxation of the walls of the heart; develops a template signal that corresponds to the observed contraction and relaxation of the walls of the heart during systole and diastole; and uses the template signal to modify the delivery of therapeutic stimulations being provided to the heart so that the heart's function during systole and diastole is improved.
[0009] In another aspect, the invention relates to an implantable assessment device that includes a controller configured to accept inputs related to cardiomechanical strain of a lateral region of a left ventricle of a heart and cardiomechanical strain of an interventricular septal region of the heart. The controller computes an interventricular dysynchrony index based upon the cardiomechanical strain input from the lateral region of a left ventricle of a heart. The controller may also determine the times of peak cardiomechanical strain from the inputs.
[0010] In yet another aspect, the invention relates to a method for assessing myocardial function using cardiomechanical sensors. The method involves acquiring data over a period of time from a first implanted myocardial mechanical sensor and a second implanted myocardial mechanical sensor separated by a distance; summating the acquired data from the first and second implanted myocardial mechanical sensors; and taking a derivative of the summated acquired data over the period of time to determine a first strain rate index.
[0011] In yet another aspect, the invention relates to an implantable cardiomechanical assessment system that includes an implantable cardiomechanical sensor system comprising at least a first myocardial mechanical sensor and a second myocardial mechanical sensor. The system also includes an implantable controller system coupled to the implantable cardiomechanical sensor system that is configured to acquire data over a period of time from the first implanted myocardial mechanical sensor and the second implanted myocardial mechanical sensor, summate the acquired data and calculate a derivative of the summated acquired data to determine a first strain rate index.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Further features and advantages of the present disclosure may be more readily understood by reference to the following description, taken in conjunction with the accompanying drawings, in which:
[0013] FIG. 1 is a simplified diagram illustrating an implantable stimulation device in electrical communication with at least three leads implanted into a patient's heart for delivering multi-chamber stimulation and shock therapy.
[0014] FIG. 2A is a functional block diagram of a multi-chamber implantable stimulation device illustrating the basic elements of a stimulation device which can provide cardioversion, defibrillation and pacing stimulation in four chambers of the heart.
[0015] FIG. 2B illustrates a cross section of an embodiment of a cardiomechanical electric sensor.
[0016] FIG. 3A is a micrograph of a segment of myocardium. FIGS. 3B and 3C are schematic representations of muscle undergoing lengthening and shortening, respectively.
[0017] FIG. 4 shows graphs of myocardium tissue velocity and displacement derived from tissue tracking echocardiogram data.
[0018] FIG. 5A shows tissue velocity curves for normal heart tissue segments from the apical region of the heart to the basal region of the heart.
[0019] FIG. 5B shows velocity, displacement, strain rate and strain curves for myocardial tissue at the apex, mid-wall and base of the heart.
[0020] FIG. 6 is a schematic illustration of two leads, one disposed relative to the left ventricle and the other disposed relative to the right ventricle, each including a cardiomechanical electric sensor (CMES) for sensing one or more of myocardial motion and deformation.
[0021] FIG. 7 is another schematic of the leads of FIG. 6 further depicting features related to myocardial velocity calculation.
[0022] FIG. 8A shows two CMESs, one disposed in the interventricular septal region of the heart and the other in the coronary sinus region of the heart, being used to detect ventricular dysynchrony.
[0023] FIG. 8B shows two CMESs, one disposed in the interventricular septal region of the heart and the other in the lateral region of the left ventricle of the heart, being used to detect ventricular dysynchrony.
[0024] FIG. 8C are schematic voltage graphs from the two CMES electrodes.
[0025] FIG. 9 depicts a block diagram for determining AV and VV timing settings that do not result in dysynchrony by using CMES and the Matrix Optimization Method.
[0026] FIG. 10A is a diagram of one CMES disposed in the coronary sinus region of the heart, being used to detect radial deformation and rotation of the heart.
[0027] FIG. 10B is a diagram of two CMESs, one disposed in the apical region of the heart and the other in the basal region of the heart, being used to detect torsional deformation of the heart.
[0028] FIG. 10C is a schematic of two CMES lead configurations, one with CMES material deposited in strips parallel to the lead axis and the other with CMES material deposited in a helical configuration around the lead.
[0029] FIG. 10D shows a graph of cardiac translation and expansion and a graph of cardiac rotation.
[0030] FIG. 11 shows how polarity of the CMES signal can be inferred from graphs of an EGM, the raw CMES signal, the longitudinal velocity and the rotational velocity.
[0031] FIG. 12 is a block diagram for calculating the torsion of the heart.
[0032] FIG. 13 shows a surface ECG, a curve representing dCMES/dt and a displacement curve derived from actual porcine data using an embodiment of a CMES in the right ventricle.
[0033] FIG. 14 shows a surface ECG, a curve representing dCMES/dt and a displacement curve derived from actual porcine data using an embodiment of a CMES in the left ventricle.
[0034] FIG. 15 shows a surface ECG, an inverted curve representing dCMES/dt and an inverted displacement curve derived from actual porcine data using an embodiment of a CMES in the left ventricle.
[0035] FIG. 16 shows how averaging of the measured mechanical stress waveforms can be synchronized with the detected heart events, such as spontaneous R-waves or stimulated events such as valvular heart sounds.
[0036] FIG. 17 is a block diagram for taking CMES measurements when the patient is in a state of relative hypopnea or apnea.
DETAILED DESCRIPTION
[0037] Reference will now be made to the drawings wherein like numerals refer to like parts throughout. The following description is of the best mode presently contemplated for practicing the invention. This description is not to be taken in a limiting sense but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be ascertained with reference to the issued claims. In the description of the invention that follows, like numerals or reference designators will be used to refer to like parts or elements throughout.
[0038] In one embodiment, as shown in FIG. 1 , an implantable cardiac stimulation device 10 is in electrical communication with a patient's heart 12 by way of three leads, 20 , 24 and 30 , suitable for delivering multi-chamber stimulation and shock therapy. To sense atrial cardiac signals and to provide right atrial chamber stimulation therapy, the stimulation device 10 is coupled to an implantable right atrial lead 20 having at least an atrial tip electrode 22 , which typically is implanted in the patient's right atrial appendage.
[0039] To sense left atrial and ventricular cardiac signals and to provide left chamber pacing therapy, the stimulation device 10 is coupled to a “coronary sinus” lead 24 designed for placement in the “coronary sinus region” via the coronary sinus ostium (OS) for positioning a distal electrode adjacent to the left ventricle and/or additional electrode(s) adjacent to the left atrium. As used herein, the phrase “coronary sinus region” refers to the vasculature of the left ventricle, including any portion of the coronary sinus, great cardiac vein, left marginal vein, left posterior ventricular vein, middle cardiac vein, and/or small cardiac vein or any other cardiac vein accessible by the coronary sinus.
[0040] Accordingly, an exemplary coronary sinus lead 24 is designed to receive atrial and ventricular cardiac signals and to deliver left ventricular pacing therapy using at least a left ventricular tip electrode 26 , left atrial pacing therapy using at least a left atrial ring electrode 27 , and shocking therapy using at least a left atrial coil electrode 28 .
[0041] The stimulation device 10 is also shown in electrical communication with the patient's heart 12 by way of an implantable right ventricular lead 30 having, in this embodiment, a right ventricular tip electrode 32 , a right ventricular ring electrode 34 , a right ventricular (RV) coil electrode 36 , and a superior vena cava (SVC) coil electrode 38 . Typically, the right ventricular lead 30 is transvenously inserted into the heart 12 so as to place the right ventricular tip electrode 32 in the right ventricular apex so that the RV coil electrode will be positioned in the right ventricle and the SVC coil electrode 38 will be positioned in the superior vena cava. Accordingly, the right ventricular lead 30 is capable of receiving cardiac signals, and delivering stimulation in the form of pacing and shock therapy to the right ventricle.
[0042] The right atrial lead 20 , the coronary sinus lead 24 , and the right ventricular lead 30 can all incorporate cardiomechanical electric sensor (CMES) material so that the leads can function to provide cardiac mechanical motion data as described herein.
[0043] As illustrated in FIG. 2A , a simplified block diagram is shown of the multi-chamber implantable stimulation device 10 , which is capable of treating both fast and slow arrhythmias with stimulation therapy, including cardioversion, defibrillation, and pacing stimulation. While a particular multi-chamber device is shown, this is for illustration purposes only and one of skill in the art could readily duplicate, eliminate or disable the appropriate circuitry in any desired combination to provide a device capable of treating the appropriate chamber(s) with cardioversion, defibrillation and pacing stimulation.
[0044] The housing 40 for the stimulation device 10 , shown schematically in FIG. 2A , is often referred to as the “can”, “case” or “case electrode” and may be programmably selected to act as the return electrode for all pacemaker “unipolar” modes. The housing 40 may further be used as a return electrode alone or in combination with one or more of the coil electrodes, 28 , 36 and 38 , for shocking purposes. The housing 40 further includes a connector (not shown) having a plurality of terminals 42 , 44 , 46 , 48 , 52 , 54 , 56 , and 58 (shown schematically and, for convenience, the names of the electrodes to which they are connected are shown next to the terminals). As such, to achieve right atrial sensing and pacing, the connector includes at least a right atrial tip terminal (A R TIP) 42 adapted for connection to the atrial tip electrode 22 .
[0045] To achieve left chamber sensing, pacing and shocking, the connector includes at least a left ventricular tip terminal (V L TIP) 44 , a left atrial ring terminal (A L RING) 46 , and a left atrial shocking terminal (A L COIL) 48 , which are adapted for connection to the left ventricular tip electrode 26 , the left atrial ring electrode 27 , and the left atrial coil electrode 28 , respectively.
[0046] To support right chamber sensing, pacing and shocking, the connector further includes a right ventricular tip terminal (V R TIP) 52 , a right ventricular ring terminal (V R RING) 54 , a right ventricular shocking terminal (RV COIL) 56 , and an SVC shocking terminal (SVC COIL) 58 , which are adapted for connection to the right ventricular tip electrode 32 , right ventricular ring electrode 34 , the RV coil electrode 36 , and the SVC coil electrode 38 , respectively.
[0047] At the core of the stimulation device 10 is a programmable microcontroller 60 which controls the various modes of stimulation therapy. As is well known in the art, the microcontroller 60 typically includes a microprocessor, or equivalent control circuitry, designed specifically for controlling the delivery of stimulation therapy and may further include RAM or ROM memory, logic and timing circuitry, state machine circuitry, and I/O circuitry. Typically, the microcontroller 60 includes the ability to process or monitor input signals (data) as controlled by a program code stored in a designated block of memory. The details of the design and operation of the microcontroller 60 are not critical to the invention. Rather, any suitable microcontroller 60 may be used that carries out the functions described herein. The use of microprocessor-based control circuits for performing timing and data analysis functions are well known in the art.
[0048] As shown in FIG. 2A , an atrial pulse generator 70 and a ventricular pulse generator 72 generate pacing stimulation pulses for delivery by the right atrial lead 20 , the right ventricular lead 30 , and/or the coronary sinus lead 24 via an electrode configuration switch 74 . It is understood that in order to provide stimulation therapy in each of the four chambers of the heart, the atrial and ventricular pulse generators 70 , 72 may include dedicated, independent pulse generators, multiplexed pulse generators, or shared pulse generators. The pulse generators 70 , 72 are controlled by the microcontroller 60 via appropriate control signals, 76 and 78 , respectively, to trigger or inhibit the stimulation pulses.
[0049] The microcontroller 60 further includes timing control circuitry 79 which is used to control the timing of such stimulation pulses (e.g., pacing rate, atrio-ventricular (AV) delay, atrial interconduction (A-A) delay, or ventricular interconduction (V-V) delay, etc.) as well as to keep track of the timing of refractory periods, PVARP intervals, noise detection windows, evoked response windows, alert intervals, marker channel timing, etc., which is well known in the art.
[0050] The switch 74 includes a plurality of switches for connecting the desired electrodes to the appropriate I/O circuits, thereby providing complete electrode programmability. Accordingly, the switch 74 , in response to a control signal 80 from the microcontroller 60 , determines the polarity of the stimulation pulses (e.g., unipolar, bipolar, combipolar, etc.) by selectively closing the appropriate combination of switches (not shown) as is known in the art. In this embodiment, the switch 74 also supports simultaneous high resolution impedance measurements, such as between the case or housing 40 , the right atrial electrode 22 , and right ventricular electrodes 32 , 34 as described in greater detail below.
[0051] Atrial sensing circuits 82 and ventricular sensing circuits 84 may also be selectively coupled to the right atrial lead 20 , coronary sinus lead 24 , and the right ventricular lead 30 , through the switch 74 for detecting the presence of cardiac activity in each of the four chambers of the heart. Accordingly, the atrial (ATR. SENSE) and ventricular (VTR. SENSE) sensing circuits 82 , 84 may include dedicated sense amplifiers, multiplexed amplifiers, or shared amplifiers. The switch 74 determines the “sensing polarity” of the cardiac signal by selectively closing the appropriate switches, as is also known in the art. In this way, the clinician may program the sensing polarity independently of the stimulation polarity.
[0052] Each sensing circuit 82 , 84 preferably employs one or more low power, precision amplifiers with programmable gain and/or automatic gain control, bandpass filtering, and a threshold detection circuit, as known in the art, to selectively sense the cardiac signal of interest. The automatic gain control enables the device 10 to deal effectively with the difficult problem of sensing the low amplitude signal characteristics of atrial or ventricular fibrillation. The outputs of the atrial and ventricular sensing circuits 82 , 84 are connected to the microcontroller 60 which, in turn, are able to trigger or inhibit the atrial and ventricular pulse generators 70 , 72 respectively, in a demand fashion in response to the absence or presence of cardiac activity in the appropriate chambers of the heart.
[0053] For arrhythmia detection, the device 10 utilizes the atrial and ventricular sensing circuits 82 , 84 to sense cardiac signals to determine whether a rhythm is physiologic or pathologic. As used herein “sensing” is reserved for the noting of an electrical signal, and “detection” is the processing of these sensed signals and noting the presence of an arrhythmia. The timing intervals between sensed events (e.g., P-waves, R-waves, and depolarization signals associated with fibrillation) are then classified by the microcontroller 60 by comparing them to a predefined rate zone limit (i.e., bradycardia, normal, low rate VT, high rate VT, and fibrillation rate zones) and various other characteristics (e.g., sudden onset, stability, physiologic sensors, and morphology, etc.) in order to determine the type of remedial therapy that is needed (e.g., bradycardia pacing, anti-tachycardia pacing, cardioversion shocks or defibrillation shocks, collectively referred to as “tiered therapy”).
[0054] Cardiac signals are also applied to the inputs of an analog-to-digital (A/D) data acquisition system 90 . The data acquisition system 90 is configured to acquire intracardiac electrogram (IEGM) signals, convert the raw analog data into a digital signal, and store the digital signals for later processing and/or telemetric transmission to an external device 102 . The data acquisition system 90 is coupled to the right atrial lead 20 , the coronary sinus lead 24 , and the right ventricular lead 30 through the switch 74 to sample cardiac signals across any pair of desired electrodes.
[0055] The microcontroller 60 is further coupled to a memory 94 by a suitable data/address bus 96 , wherein the programmable operating parameters used by the microcontroller are stored and modified, as required, in order to customize the operation of the stimulation device 10 to suit the needs of a particular patient. Such operating parameters define, for example, pacing pulse amplitude, pulse duration, electrode polarity, rate, sensitivity, automatic features, arrhythmia detection criteria, and the amplitude, waveshape and vector of each shocking pulse to be delivered to the patient's heart 12 within each respective tier of therapy.
[0056] Advantageously, the operating parameters of the implantable device 10 may be non-invasively programmed into the memory 94 through a telemetry circuit 100 in telemetric communication with the external device 102 , such as a programmer, transtelephonic transceiver, or a diagnostic system analyzer. The telemetry circuit 100 is activated by the microcontroller by a control signal 106 . The telemetry circuit 100 advantageously allows IEGMs and status information relating to the operation of the device 10 (as contained in the microcontroller 60 or memory 94 ) to be sent to the external device 102 through an established communication link 104 .
[0057] In the preferred embodiment, the stimulation device 10 further includes a physiologic sensor 108 , commonly referred to as a “rate-responsive” sensor because it is typically used to adjust pacing stimulation rate according to the exercise state of the patient. However, the physiological sensor 108 may further be used to detect changes in cardiac output, changes in the physiological condition of the heart, or diurnal changes in activity (e.g., detecting sleep and wake states). Accordingly, the microcontroller 60 responds by adjusting the various pacing parameters (such as rate, AV Delay, V-V Delay, etc.) at which the atrial and ventricular pulse generators 70 , 72 generate stimulation pulses.
[0058] The stimulation device additionally includes a battery 110 which provides operating power to all of the circuits shown in FIG. 2A . For the stimulation device 10 , which employs shocking therapy, the battery 110 must be capable of operating at low current drains for long periods of time and then be capable of providing high-current pulses (for capacitor charging) when the patient requires a shock pulse. The battery 110 must also have a predictable discharge characteristic so that elective replacement time can be detected. Accordingly, embodiments of the device 10 including shocking capability preferably employ lithium/silver vanadium oxide batteries. For embodiments of the device 10 not including shocking capability, the battery 110 will preferably be lithium iodide or carbon monofluoride or a hybrid of the two.
[0059] As further shown in FIG. 2A , the device 10 is shown as having an impedance measuring circuit 112 which is enabled by the microcontroller 60 via a control signal 114 .
[0060] In the case where the stimulation device 10 is intended to operate as an implantable cardioverter/defibrillator (ICD) device, it must detect the occurrence of an arrhythmia, and automatically apply an appropriate electrical shock therapy to the heart aimed at terminating the detected arrhythmia. To this end, the microcontroller 60 further controls a shocking circuit 116 by way of a control signal 118 . The shocking circuit 116 generates shocking pulses of low (up to 0.5 joules), moderate (0.5-10 joules), or high energy (11 to 40 joules), as controlled by the microcontroller 60 . Such shocking pulses are applied to the patient's heart 12 through at least two shocking electrodes, and as shown in this embodiment, selected from the LA coil electrode 28 , the RV coil electrode 36 , and/or the SVC coil electrode 38 . As noted above, the housing 40 may act as an active electrode in combination with the RV electrode 36 , or as part of a split electrical vector using the SVC coil electrode 38 or the LA coil electrode 28 (i.e., using the RV electrode as a common electrode).
[0061] Cardioversion shocks are generally considered to be of low to moderate energy level (so as to minimize pain felt by the patient), and/or synchronized with an R-wave and/or pertaining to the treatment of tachycardia. Defibrillation shocks are generally of moderate to high energy level (i.e., corresponding to thresholds in the range of 5-40 joules), delivered asynchronously (since R-waves may be too disorganized), and pertaining exclusively to the treatment of fibrillation. Accordingly, the microcontroller 60 is capable of controlling the synchronous or asynchronous delivery of the shocking pulses.
[0062] A variety of diseases such as cardiomyopathy, congestive heart failure, hypertrophic cardiomyopathy, aortic stenosis and ischemic heart disease show characteristic abnormalities in myocardial strain, myocardial tissue velocity and myocardial tissue displacement, rotation and torsion. Tissue Doppler imaging (TDI) data is used to derive myocardial strain and strain rate by analysis of regional disparities in tissue velocity or the spatial location of ultrasonic reflectors (speckle tracking) as a function of time. This information is used clinically to evaluate properties of myocardial motion and deformation that provide insight into the electromechanics of the heart.
[0063] In some embodiments, lead-based sensors may be used as an alternative to TDI for generating quantitative information which relates to the same properties such as myocardial strain, myocardial strain rate, myocardial tissue velocity and myocardial tissue displacement, rotation and torsion. Sensors capable of acquiring this data can be used for monitoring purposes and communicate information related to cardiac performance and dysynchrony to the clinician. The same data can be used as part of a closed loop system for CRT timing.
[0064] Piezoelectric materials will generate a voltage when subject to mechanical stress or strain, with the magnitude of voltage dependent upon the magnitude of the stress or strain. In some embodiments, sensors comprised of piezoelectric material and positioned in locations optimal for detection of cardiac deformation and/or motion generate raw signals of cardiac mechanical data that can be further processed into myocardial strain, myocardial strain rate, myocardial tissue velocity and myocardial tissue displacement, rotation and torsion data.
[0065] Embodiments of CMESs may comprise one or more piezoelectric transducers, which convert mechanical motion into electrical signals. As illustrated in cross section in FIG. 2B , in some embodiments, a CMES 200 comprises a tubular and/or annular piezoelectric element 210 , either self-supporting or disposed on a supporting structure. In some embodiments, conductors 220 contact the inner and outer surfaces of the tubular or annular element 210 . Electrical connections 230 are coupled to the conductors 220 .
[0066] In preferred embodiments, the sensor 200 is dimensioned for incorporation into a lead. For example, in some embodiments, the outer diameter of the sensor 200 is similar to the outer diameter of a lead, permitting the sensor to be disposed at any position along a lead without causing a profile change that could affect placement of the lead. In some embodiments, one or more of an electrode and/or other sensors is disposed over at least a portion of the sensor 200 . A longitudinal passageway 240 through the sensor 200 in the illustrated embodiment permits routing electrical and/or other types of connections therethrough, for example, from one or more electrodes and/or sensors disposed on the same lead.
[0067] The conductors 220 comprise any suitable material known in the art, for example, titanium, titanium alloy, titanium nitride, platinum, platinum alloy, carbon, niobium, niobium alloy, tantalum, tantalum alloy, gold, combinations, and the like. In some embodiments, a patient's tissue is used as one of the conductors. In some embodiments, an elastomer is disposed over the sensor 200 (not illustrated). Preferred elastomers are biocompatible, including, for example, silicones, polyurethanes, ethylene-propylene copolymers, fluorinated elastomers, combinations, and the like.
[0068] In some embodiments, the piezoelectric element comprises a relatively hard material, thereby permitting reliable measurements with only small deflections of the piezoelectric material. Preferred piezoelectric materials are biocompatible, for example, ceramic piezoelectric materials, including ceramic ferroelectric particles, lead zirconate titanate (lead zirconium titanate, PZT), barium titanate, sodium potassium niobate, and the like. In some embodiments, the piezoelectric material comprises Na 0.5 K 0.5 NbO 3 , for example, as described in U.S. Pat. No. 6,526,984. Other piezoelectric materials or deformation-based sensors may also be used.
[0069] One preferred sensor configuration comprises a piezoelectric material that is thin and covers a large amount of myocardial tissue surface area. Covering a large surface area provides global deformation data in comparison to the local information acquired by CMES material deposited in a smaller region. In order for data to be representative of myocardial deformation the CMES preferably contacts myocardium, and thus, the CMES is preferably located along the distal portion of a lead body and contours along either a large caliber coronary sinus lead or the epicardial surface if the CMES is deployed via a limited thoracotomy (e.g., a pericardial or epicardial approach).
[0070] In other embodiments, the CMES comprises a conductive polymer that has a resistance that changes as a function of strain. By measuring the resistance of the conductive polymer, the strain can be determined. The conductive polymer can be polyacetylene, polyaniline, polypyrrole or any other suitable conductive polymer.
[0071] In some embodiments that use piezoelectric materials, the raw CMES signal is a measurement of deformation (strain), and can be expressed in units of voltage. Referring to FIG. 3A , which depicts a micrograph of some isolated cardiac muscle fibers 304 from the heart, contraction and relaxation of the myocytes may be quantified by the deformation of adjacent mechanical sensors. Strain in the myocardium may be measured by the change in relevant length of myocardium:
[0000] Strain= e =( L−Lo )/ Lo (Eq. 1)
[0000] The strain (e) given by Eq. 1 is a dimensionless quantity. Strain is measure of a fractional change from unstressed dimension given by the unstressed zero length. Referring to FIGS. 3B and 3C , an expansion to the muscle fiber 304 length L 302 from the initial length Lo 300 represents a positive strain, while a compression and dimensional shortening represents a negative strain L 302 .
[0072] A first order derivative of the raw strain signal with respect to time generates a measure of the deformation (strain) rate. The calculated quantity, strain rate, with the unit 1/s is a measure of the rate of deformation and is equivalent to the shortening or lengthening velocity per fiber length.
[0073] The microcontroller 60 can also comprise circuitry to process data obtained by the CMES as described herein as part of a closed loop system. Alternatively, the data obtained by the CMES can be communicated to an external device 102 and processed thereafter.
Derivation of CMES Derived Deformation and Velocity Indices
[0074] FIG. 4 depicts a velocity curve 400 of a region of the myocardium 402 generated by tissue tracking data derived from echocardiographs 404 . Tissue tracking images are two-dimensional maps that display color-coded tissue velocity information and can be used to identify wall motion abnormalities and to estimate regional strain or shortening of the myocardium. Tissue tracking may be particularly useful in identifying wall motion abnormalities that may be treated with resynchronization therapy or may be used to optimize resynchronization therapy. A time of integral of the velocity curve 400 yields a displacement curve 406 of the same region of myocardium.
[0075] FIG. 5A depicts echo-generated tissue velocity curves 400 in the apical to basal regions of the heart. The y-axis 502 represents the velocity, the x-axis 504 represents time and the area under the curve 506 , which can be obtained by integrating the velocity curve 400 , represents tissue displacement. FIG. 5B shows a velocity curve 400 , a displacement curve 406 which can be obtained by integrating the velocity curve 400 , a strain rate curve 510 and a strain curve 512 which can be obtained by integrating the strain rate curve 510 in the apex 514 , mid-wall 516 and base 518 of the heart.
[0076] As shown in FIGS. 5A , and 5 B, along a longitudinal axis generally parallel to the spine, the heart contracts and moves from base to apex during systole. The heart relaxes and moves in the opposite direction, from apex to base, during diastole. The basal regions generally move a greater distance, an average of approximately 12 mm at most basal segments, than the apical regions, which move approximately 0-2 mm at cardiac apex. A measurement of the relative difference in distance that any two regions traverse will generate longitudinal deformation (strain) information. Echocardiographic techniques such as tissue tracking demonstrate this displacement phenomenon as well as characteristics of velocity, strain and strain rate.
[0077] In some embodiments, as shown in FIG. 6 , a CMES-bearing device 600 , such as an LV lead, is positioned with respect to the left ventricle (LV) such that a portion of the lead incorporating CMES material 604 is substantially parallel to the cardiac central longitudinal axis (CLA) to thereby acquire longitudinal deformation information. Similar information can be acquired by positioning another CMES-bearing device 602 , such as an RV lead, such that a portion of the lead incorporating CMES material 606 is substantially parallel with the CLA. Both CMES devices 600 , 602 generate data related to the motion of the cardiac apex relative to the base if the CMES material 604 , 606 covers enough surface area along the CLA of the heart and contacts myocardial tissue. The greater the distance (base to apex) the CMES material 604 , 606 traverses, the greater the amount of resultant deformation and the more global the representation of cardiac motion will be. In the case of the RV lead 602 , additional CMESs 608 , 610 may be included. Basally located CMES 610 will deform more than apically located CMES 608 and thus be more sensitive to changes in global cardiac geometry.
[0078] In some embodiments, regional contractile information can be generated from CMES material that covers a short distance. In normal hearts or hearts with global decreases in contractility (strain, deformation) such a reduced surface area electrode can provide information about global cardiac contractile function because any regional properties are homogeneous with global properties (e.g. dilated cardiomyopathy). However, in more anisotropic conditions, whether in the space domain or time domain, such as ischemic cardiomyopathy or electromechanical dysynchrony, respectively, regional information provides little information about global cardiac contractile function. As the heart is embryologically and structurally derived from a single muscle band that has certain deformation properties, tethering effects (e.g. regional myocardial shortening has a pulling effect on surrounding myocardium) create some degree of interrelation between regional and global cardiac deformation. Thus, CMES acquired data in the longitudinal axis will provide clinically relevant information if the material covers enough surface area (e.g. longitudinal lead length).
[0079] Relative differences in tissue velocity can be used to determine myocardial strain rate derived by using the strain rate equation. This technique is implemented in sophisticated echocardiography machines that are capable of tissue Doppler imaging for quantifying regional myocardial strain rate, strain, velocity and displacement. This equation can be similarly applied herein to derive analogous indices descriptive of the same myocardial properties using implanted CMES technology. The strain rate (SR) equation is:
[0000] SR =( Vb−Va )/ x (Eq. 2)
[0000] where Vb and Va represent regional velocities at points b and a, respectively, SR=strain rate and x=length between points a and b. The calculated strain rate is representative of the myocardial deformation in the region encompassing points a and b where the tissue velocities were measured. Similarly, Eq. 2 can be utilized to derive estimated tissue velocity information of cardiac motion by using the strain rate between points a and b measured with a CMES sensor capable of measuring strain. Taking the derivative of the strain with respect to time yields the strain rate, which can then be used in Eq. 2 to determine velocity information.
[0080] For example in some embodiments, as shown in FIG. 7 , if CMES material 604 in series and in contact with the myocardium at points a 700 and b 702 , which are separated by distance x 704 , the resultant summed deformation voltage Vsum that is generated by the series sensor material 604 provides strain information produced along distance x 704 and can be used to derive a deformation index. This property may also be acquired by depositing CMES material 604 along a relatively long portion of an implanted lead in contact with myocardium. In some embodiments, distance x 704 is in a range of about 4 mm to about 30 mm, preferably about 5 mm to about 20 mm, and most preferably about 5 mm to about 10 mm.
[0081] The first derivative of the signal generated from CMES deformation between points a and b as a function of time, dVsum/dt=dCMES/dt, is proportionate to SR and can be used to derive a SR index that can be plotted as a function of time. The integration of the SR index can be performed to derive an index of strain, which in some embodiments is an index of longitudinal strain. The measure of strain or strain rate between points a and b can be used to detect a myocardial infarct by comparing the measured strain or strain rate values with expected or normal strain or strain rate values. Abnormally low strain or strain rate values may indicate the presence of a myocardial infarct.
[0000] d CMES/ dt=SR Index (Eq. 3)
[0082] In order to derive regional velocity information, a velocity index, Vi, can be defined that is representative of the spatial velocity gradient between points a and b, having a distance x, where Vb and Va represent regional velocities at points b and a, respectively. Rearranging Eq. 2, the strain rate equation, and substituting Vi for Vb−Va yields:
[0000] Vi=Vb−Va =( SR Index)*( x ) (Eq. 4)
[0083] Thus, by combining Eq. 3 and Eq. 4, the CMES derived Velocity Index, Vi, equals the first order derivative, d(CMES)/dt, multiplied by x, where x is the span of the distance between CMES electrodes a and b (or length along a lengthy CMES electrode). This index can be expressed in units, Voltage-cm/sec.
[0000] CMES Velocity Index= d (CMES)/ dt*x (Eq. 5)
[0000] This index can be measured instantaneously by using d(CMES)/dt max or measured as a function of time during the cardiac cycle. This index generally parallels Tissue Doppler measurements of myocardial velocity. Integration of this velocity waveform will provide displacement information and measurements such as peak longitudinal displacement can be derived.
[0084] An alternate means of deriving an index of myocardial velocity is by defining the pure CMES signal as a measurement of motion (e.g. velocity, acceleration). In order for the CMES to represent motion rather than deformation, the CMES is preferably not fixated to myocardium and is instead relatively free floating.
Dysynchrony Index
[0085] In some embodiments, as shown in FIGS. 8A and 8B , if two or more CMESs 800 , 802 are deployed in interventricular septal and LV lateral regions, respectively, information about dysynchrony can be derived. One CMES 802 can be deployed in the LV lateral region via the coronary sinus region ( FIG. 8A ) or by a transeptal approach ( FIG. 8B ). Alternatively, a pericardial approach (not shown) may be used to place the CMES 802 in the LV lateral region. Though electromechanical dysynchrony is an anisotropic property, differences between septal and lateral wall motion are often seen in patients suffering from dysynchrony and such measurements are considered specific indicators of patients who respond to cardiac resynchronization therapy (CRT) device implants. Thus, as shown in FIG. 8C , time of peak CMES Voltage (tCMESpeak) from the septal sensor 800 and lateral sensor 802 located in the distal portion of lead and proximate to myocardium may be used together to provide a CMES Dysynchrony Index or other parameter that is indicative of the time to peak myocardial strain, which is a currently utilized ultrasonic measurement of dysynchrony. In another embodiment, RV apically placed leads may generate similar information if the CMES material deformation is congruent with septal deformation during the cardiac cycle.
[0000]
CMES
Dysynchrony
Index
=
(
tCMESpeak
septal
)
(
tCMESpeak
lateral
)
(
Eq
.
6
)
[0086] Alternatively, time to peak d(CMES)/dt, which will parallel measurements of time to peak SR, can be used instead to calculate the CMES Dysynchrony Index.
[0087] Other features of the CMES signal can be used for timing (e.g. time of onset of CMES voltage waveform (Vcmes) or time to peak dVcmes/dt). Generally, the relative timings of the CMES generated signals in opposing regions of interest, for example myocardial wall segments, can be utilized for deriving a dysynchrony index.
[0088] As the CMES Dysynchrony Index approaches a value of one, conditions of synchrony will be present. Ideally, this time will occur during the latter portion of the systolic ejection phase, when strain 512 is maximal in normal hearts, as shown in FIG. 5B . As changes in interval timing occur, the index may be followed and the programmed intervals that yield an index that is closest to unity will be optimal. Changes in atrioventricular (AV) and interventricular (VV) timing can be made such that multiple permutations of AV and VV intervals are evaluated because changes in AV timing and VV timing do not have mutually exclusive effects on cardiac synchrony or systolic or diastolic performance. As shown in FIG. 9 , an array or matrix 900 of several AV and VV intervals can be tested using a Matrix Optimization Method (MOM) while the CMES Dysynchrony Index (CMES DI) is evaluated for each permutation. MOM is described in greater detail in U.S. Pat. No. 7,010,347, herein incorporated by reference in its entirety. Regarding CMES DI evaluation, at block 904 CMES DI is calculated for a set of current AV and VV intervals. At block 906 the calculated CMES DI is compared to unity plus or minus a default value (e.g. a programmable standard deviation). If the CMES DI does not equal unity plus or minus the default value, the process returns to block 902 where another set of AV and VV intervals are selected and block 904 where another CMES DI is calculated. Once CMES DI equals unity plus or minus a default value, the tested AV and VV intervals are programmed into the device at block 912 . The standard deviation can be derived by analysis of previous values during earlier optimization efforts.
[0089] The CMES Dysynchrony Index may also be used with intracardiac electrogram (IEGM) data for monitoring electromechanical dysynchrony in the heart. If electromechanical dysynchrony is detected, lead based CMES electrodes, as described herein, can be used to implement resynchronization timing therapy as part of a closed loop system. See, for example, U.S. Pat. No. 7,010,347, previously incorporated by reference.
Radial Deformation and Cardiac Rotation
[0090] With reference to FIGS. 10A and 10B , in some embodiments, CMESs 1010 may be deployed circumferentially along the proximal to lateral portion of the main coronary sinus branch (endovascular leads) ( FIG. 10A ), or along the AV groove (pericardial leads) ( FIG. 10B ). In these arrangements, parameters of radial deformation and motion can be derived. Radial strain can be used as a global cardiac performance index. However, radial strain is subject to regional effects and the performance of more apical segments may not be well represented, leading to the possibility that regional pathology (e.g. an mid-cavitary or apical infarct) will not be detected.
[0091] In some embodiments, a lead configuration where the CMES is in close proximity to tissue and not free-floating may be utilized to derive rotational velocity information using Eq. 5, thereby providing an index of basal cardiac rotational velocity. If this data is also acquired about the cardiac apex, which is preferably obtained with a pericardial or epicardial lead deployed using a sub-xyphoid approach as shown in FIG. 10B , relative rotational data can be acquired for derivation of a torsion index. In normal hearts, the cardiac base rotates in an opposite direction from the apex. For example, during isovolumic contraction, the base rotates counter-clockwise while the apex rotates clockwise. The opposite motion occurs during isovolumic relaxation as shown in FIG. 10D . In FIG. 10D , curve 1000 represents tissue velocity as a function of time for basilar systolic counter-clockwise rotation and diastolic counter-clockwise rotation. Curve 1002 is apical systolic clockwise rotation and diastolic counter-clockwise rotation. This torsion effect is pivotal in generating forces that contribute to isovolumic contraction, aortic valve opening and systolic forward flow and a diastolic suction effect that contributes to early diastolic rapid filling during isovolumic relaxation. Time T 1004 is diastolic filling time where no torsion is present and the heart translates and expands 1006 rather than rotates. Identification of this timeframe using intracardiac electrograms (e.g. just before and after the P wave) can assist in temporal labeling of the generated CMES signals (see below). Leads placed using a pericardial or epicardial approach are generally more appropriately oriented for generation of clinically relevant CMES signals.
[0092] In some embodiments, circumferential deformation effects (i.e. systolic circumferential shortening) will contribute to the raw radial CMES signal data. Thus, the derived rotational velocity information includes both the actual rotational velocity information plus a contribution from circumferential deformation effects. In studies using Tissue Velocity Imaging, the estimated amount of contribution of circumferential deformation to the measured velocity data is approximately 13% in normal patients and under 5% in patients with Class III or IV heart failure and ejection fraction less than 40% (personal, unpublished data). Thus, application of Eq. 5 to radially derived CMES data will provide a relatively accurate index of pure cardiac rotational velocity with some contribution from the effects of circumferential deformation. The amount of contribution of circumferential deformation and of rotational velocity to the data acquired will also relate to the amount of contact the sensor has with underlying tissue. Nonetheless, this cardiac performance index is a useful blend of rotational velocity and circumferential contractile properties. If directional information can be derived (e.g. clockwise vs. counter-clockwise) from sensors 1010 and 1012 positioned in the apex and base, respectively, as shown in FIG. 10B , a torsion index can be obtained by adding the measured indices (in essence adding the absolute values as the rotational vectors are opposite). Patients with more advanced heart failure will have less rotation and/or torsion and less circumferential deformation with a resultant translational motion without significant rotational velocities. Thus, the resulting CMES rotational and torsional index will be less in these patients. Integration of rotational or torsional dCMES/dt will derive a rotational or torsional displacement index, respectively.
Inferred Polarity
[0093] In some embodiments, embedding CMES material on an implantable lead such that the voltage generated relies on the direction of deformation will allow the derivation of more accurate representations of actual physiologic properties. For example, as shown in FIG. 10C , the CMES material 1014 can be placed in strips parallel 1016 to the long axis of a lead body 1018 or in a helical fashion 1020 about the lead body 1018 . If a lead placed about the AV ring (basal location) has CMES material embedded parallel to the lead long axis, the raw voltage signal generated is more of a function of radial deformation. If the CMES material runs in a helical fashion about the long axis of the lead, the raw voltage signal generated is more a function of circumferential deformation.
[0094] In some embodiments, if basal and apical CMES electrodes 1010 and 1012 are designed to derive rotational indices as shown in FIG. 10B , certain assumptions about direction of deformation may be made. For example, if deformation of the CMES material causes it to expand, a different voltage waveform will be generated than if the CMES material contracts. The waveform polarity will not be significantly different as the cardiac forces causing the deformation from the original length result in a voltage signal regardless of material contraction or expansion. Certain characteristics of the raw voltage signal (e.g. relative positive to negative polarity in a signal that is not rectified), however, will be seen as a result of CMES material contraction rather than expansion and vice versa. Signal processing can be applied to derive such polarity information.
[0095] Referring to FIG. 11 , the timing of the voltage signal 1100 will relate to systolic (e.g. isovolumic contraction) and diastolic (e.g. isovolumic relaxation) deformation voltages, Vsys and Vdias, respectively. Isovolumic contraction (IVC) causes a steep rise in longitudinal myocardial tissue velocity 1102 , rotational velocity 1104 , longitudinal and radial deformation (strain). IVC typically occurs shortly after depolarization. Vsys will typically occur shortly after the electrocardiogram 1106 (EGM) R wave 1108 , while Vdias will typically occur thereafter, before the EGM P wave 1110 . In a normal heart, deformation of a lead-based CMES with specific lead orientation and material characteristics (e.g. parallel to lead body, parallel to the cardiac CLA) can be expected to be a result of longitudinal rather than radial deformation. Similarly, inferences about whether a voltage signal is generated as a result of longitudinal systolic contraction rather than diastolic expansion may be made. For example, systolic longitudinal contraction will occur during IVC. This will lead to contraction of CMES material positioned along the length of a lead that is parallel to the cardiac CLA. The resulting waveform will occur after the EGM R wave and thus, the second CMES voltage waveform, Vdias, can be inferred to be a result of material expansion during diastole. Likewise, the EGM R to Vsys interval will be shorter than the EGM R to Vdias interval, and the interval from Vdias to the next EGM R will be shorter than the interval from Vsys to the next EGM R. Furthermore, Vdias will often be of lower amplitude than Vsys as the forces generated from diastolic expansion (isovolumic relaxation, IVR) are of less amplitude and are generated more slowly than systolic contraction that occurs during IVC. Identification of the temporal relationship of these waveforms to the intracardiac P wave will assist in labeling a given signal as one generated from contraction and not relaxation. These temporal and morphologic signal characteristics will allow the system to infer polarity of deformation information. Apically located CMES sensors 1112 will have an assigned polarity that is different than basally located CMES sensors 1114 which is represented on bottom of FIG. 11 as Aa and Ab, respectively. Under normal circumstances these deflections (with inferred polarity) will be in the opposite direction as shown, though in patients with congestive heart failure the amplitude will be less and the direction of these signals may be similar (secondary to translation without rotation and impaired circumferential shortening).
[0096] In the pathologic heart, these temporal and morphologic signal characteristics may be less accurate and signal processing for determination of inferred polarity will be less reliable. This is due to the increased dissociation between the electrical and mechanical properties of abnormal myocardium. Because of this, material characteristics may be modified as to generate specific raw signal voltage waveforms that are more characteristically seen with contraction or expansion. With such CMES characteristics, signal processing to derive the inferred polarity can be simplified and the resulting information more accurate.
[0097] In some embodiments as shown in FIG. 12 , the apical and basal CMES signals are processed at blocks 1200 , 1202 . The processed signals are then vector labeled based on temporal and morphologic characteristics at block 1220 . At block 1240 , a subtraction function is utilized to calculate the difference in rotation between Aa 1112 and Ab 1114 (bottom of FIG. 11 ). The accuracy of the subtraction function is dependent upon appropriate vector labeling. At block 1260 a torsion calculator is optionally implemented to generate data in numerical format that is communicated 1280 from the device to the programmer via wireless telemetry. Alternatively, some of the processes shown in FIG. 12 can be performed within the programmer itself. In some embodiments, torsional velocity calculation is performed by analysis of relative values from basal and apical CMES sensors as described above. Derivation of a rotational displacement index can be performed by integration of the derived rotational velocity waveform.
[0098] It is noteworthy to mention that a combination of the forces generated during isovolumic contraction and relaxation will contribute to the development of the CMES signal and direction specific information may not always be able to be characterized. Thus, in some embodiments, CMES data can provide a crude representation of deformation and/or motion. The more myocardial surface area the CMES material covers, the more physiologically accurate the derived indices will be at characterizing the mechanical events occurring during isovolumic contraction and relaxation. It is also noteworthy to mention that the temporal characteristics of the raw CMES voltage signal occur on or about the time of mitral valve and aortic valve closure, but are only temporally related to these events rather than representative of valvular mechanics. Under circumstances where the CMES sensor is free floating, myocardial acceleration (and possibly dP/dt, the rate of change in blood pressure at the sensor site) and acoustical information may be derived.
[0099] Any and all of the data described herein can be used for monitoring cardiac performance and properties of dysynchrony. Likewise, the same data can be implemented for optimization of interval timing for any multi-site pacing system in a closed loop fashion as depicted in FIG. 9 which describes the Matrix Optimization Method.
[0100] In an alternate embodiment, periodic interval monitoring is used to derive any of the indices described herein. During time frames where diagnostic data is not collected, the voltage generated from the CMESs is stored as energy to reduce the costs to the system (e.g. battery longevity) of operating such software.
[0101] FIG. 13 represents actual porcine animal data with an embodiment of a CMES in the ring or proximal position of a pacing electrode in the RV apex, where the electrode tip is in tissue contact but the CMES is not in close contact to myocardium. The top signal is a surface ECG 1300 , the middle signal is a first order derivative, dCMES/dt 1302 , similar in quality and in its temporal relationship to tissue Doppler derived myocardial velocity time graphs depicted and described above ( FIG. 5B ). The integral of this data, CMES 1304 , bottom signal, is displacement. Peak systolic RV apical displacement is identified in the figure by arrow 1306 . Comparable data can be acquired from a larger surface area CMES that is basally located and parallel to the cardiac longitudinal axis. A higher fidelity signal more representative of global cardiac displacement can be derived from such a sensor. Summation averaging of multiple waveforms will provide data with improved signal to noise ratio.
[0102] FIG. 14 represents actual porcine animal data with an embodiment of a CMES sensor in the LV anterior interventricular vein located ⅔ the distance from the apex toward the base parallel to the cardiac longitudinal axis. The sensor is in contact with the underlying tissue. The waveforms 1400 and 1402 derived are more representative of myocardial deformation and strain. Thus, dCMES/dt is an index of strain rate and the integral of this provides an index of strain. The strain/strain rate time graphs are similar to those acquired using tissue Doppler imaging and speckle tracking techniques described above. Inversion of the waveforms 1400 and 1402 to derive an analogous vector 1500 and 1502 , as shown in FIG. 15 , demonstrates waveforms similar to those depicted in FIG. 5B derived from the strain rate equation (Eq. 2) being applied to Doppler derived myocardial tissue velocity imaging performed, for example, by GE Vivid series echocardiography equipment. Arrow 1504 is peak longitudinal strain.
[0103] Second order derivatives of displacement data or first order derivatives of velocity data can be used to calculate acceleration indices as well.
Interval Specific Ensemble Averaging
[0104] As shown in FIG. 16 , averaging of the measured mechanical stress waveforms is synchronized with the detected heart events, such as spontaneous R-waves 1600 or stimulated events such as valvular heart sounds 1602 detected by an implanted sonomicrometer, filtered and/or processed CMES signal, or a signal from an alternate sensor. Synchronization of data acquisition can also be triggered by an impedance based parameter or index that relates to respiration and/or myocardial mechanics. The waveform 1608 is averaged over a predetermined number of consecutive heart cycles 1606 by taking the sample average for every time distance from the detected heart event, such as a QRS complex 1604 . The number of predetermined heart cycles could for instance be 30. For example, if the sampling frequency is 1 kHz, an averaged sample value at 24 ms distance from a QRS is calculated by taking the value at 24 ms distance from a QRS for the predetermined number of heart cycles, which is 30 in this example, and then averaging the values. The averaging is repeated for all samples in the heart interval. This will result in an averaged waveform 1610 based on the predetermined number of beats (in the example 30 beats). The strain calculations are then performed using the averaged waveform 1610 . The advantage is that short term variations depending on for instance respiration are cancelled out. This method of averaging is referred to as “waveform averaging”. Having the advantage of enhancing details in the acquired waveform, the heart rate is preferably fairly stable during the process. This methodology can improve signal-to-noise ratio. Data acquisition during periods of rest and relative apnea or hypopnea will further improve the signal to noise ratio (SNR). As shown in FIG. 17 , input from a can based accelerometer 1700 , to determine whether the patient is at rest, and respirometers 1702 , to determine whether the patient is in a state of apnea or hypopnea, can trigger times for CMES data acquisition 1704 and function in conjunction with the Interval Specific Ensemble Averaging feature describe herein and in FIG. 16 .
Value Averaging
[0105] An alternative method to perform the averaging is to calculate the strain parameters for each non-averaged consecutive heart beat and then average the calculated parameters over the predetermined number of heart beats. This method of averaging is referred to as “value averaging.” Having the advantage of detecting beat-to-beat variations of the measured parameters, the heart rate does not have to be fairly stable during the process. This is particularly suitable when variability analysis is to be performed on the measured parameters.
Other Averaging Techniques
[0106] The average calculation above is performed using consecutive heart beats, numbered 1, 2, 3 . . . , and so on. Alternatively, two average values can be calculated. For example, the first value can be calculated using odd numbered beats: 1, 3, 5 . . . , and so on. The second value can be calculated using even numbered beats: 2, 4, 6 . . . , and so on. The two averaged values can be expected to be equal, but during severe heart tissue ischemia two groups can be formed. This will be the result of the 2:1 rhythmic pattern in heart beats often seen during this condition. Other manifestations are the presence of rhythmic T-wave alternans (TWA) and pulsus alternans. Processing the measured strain in this way forms a strong detector for this condition and can serve to notify the clinician that a change in physiologic status has occurred.
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A first lead provides therapeutic stimulation to the heart and includes a first mechanical sensor that measures physical contraction and relaxation of the heart. A controller induces delivery of therapeutic stimulation via the first lead. The controller receives signals from the first mechanical sensor indicative of the contraction and relaxation; develops a template signal that corresponds to the contraction and relaxation; and uses the template signal to modify the delivery of therapeutic stimulations. In another arrangement, a second lead, with a second mechanical sensor also provides signals to the controller indicative of contraction and relaxation. The first mechanical sensor is adapted to be positioned at the interventricular septal region of the heart, and the second mechanical sensor is adapted to be positioned in the lateral region of the left ventricle. The controller processes the signals from the first mechanical sensor and the second mechanical sensor to develop a dysynchrony index.
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BACKGROUND OF THE INVENTION
A typical top loading automatic clothes washing machine operation will generally consist of the following cycles, when operating in the normal wash function:
1. Fill with Water
2. Wash and Agitate
3. Drain the Water
4. Spin and Drain
5. Fill with Water
6. Rinse and Agitate
7. Drain the Water
8. Spin dry and Drain
There may also be an optional second rinse involved, which would require a repeat of cycles 5 through 8.
Many of the top loading automatic clothes washing machines that are manufactured today for household use are of large or very large capacity, because they are being loaded with a wide variety of items to be washed. These items are made of fabrics containing wool, cotton, polyesters, nylon, other synthetic fabrics and/or combinations thereof. These items range from the very light and delicate (underclothing, etc.) to the most heavy and rugged (jackets, jeans, blankets, bedspreads, mattress covers, towels, etc.). Each of the above fabrics retains water at different rates after the water has been pumped out of the tub at the end of the wash and rinse cycles.
This could present a problem in the spin cycles, even if a conscientious effort has been made to balance the load by placing similar items opposite each other in the tub. The purpose of the agitator during the wash and rinse cycles is, to keep all the items constantly moving and tumbling, so that they can be washed or rinsed properly. Therefore at the end of the wash or rinse cycles all of the items might be mixed. Because of this, there is a good possibility that the load will be unbalanced at the start of the spin or spin-dry cycles, which follow. A minimal imbalance will have no adverse effect, but if the imbalance is sufficient, the basket will wobble, causing the washing machine to make some noise and possibly start banging and move across the floor, and it may even shut itself down automatically. When this happens the washing machine has to be turned off manually and the items in the tub will have to be rearranged. This is all guess work.
The platform of the automatic washing machine (FIG. 1) contains the main working parts of the machine such as the tub, basket, agitator, water pump, transmission, electrical motor, clutch assembly, etc., and is suspended by suspension legs from the top of the side frames of the machine.
When the washing machine has a perfectly balanced load and it is in the spin or spin-dry cycle, the center of the agitator top (FIGS. 1, 3 and 4) is the pivot point for the agitator and basket, and this point will remain fixed or stationary, while the agitator and basket are spinning. When the load is unbalanced, this pivot point will not remain fixed or stationary, but will move around in its own circle. (This will give the impression that the agitator and basket are wobbling, because of their spinning speed). The amount of imbalance will determine the radius of the circle. If the weight of the imbalance is sufficient, it will cause the washing machine platform (FIG. 1) to move around in its own circle and possible to come in contact with the insides of the washing machine frame, resulting in a banging noise and the possibility of the machine moving across the floor.
If the top lid were to be opened while the washing machine is running during one of the spin cycles, whether there is an unbalanced load or not, the safety lid switch would open an electrical circuit, causing the spinning action and possible wobbling movement of the agitator and basket, to slow down and come quickly to a complete stop. When opening the top lid, when the load is unbalanced, the agitator and basket can be observed to be spinning and wobbling at their maximum speed, and rapidly decreasing to a complete stop. Since the speed and movement are directly proportional to each other, e.g.: maximum speed equals maximum wobbling movement, minimal speed equals minimum wobbling movement, it would be very hard to judge with certainty where the unbalanced part of the load is located, because, when the spinning is reduced to a speed, where you can track the items inside the basket, the wobbling has also been reduced to a point where there is hardly any movement. Therefore, there may not be any visible indication of the cause of the imbalance.
The rearranging of the items may have to be performed several times during the spin and/or spin-dry cycles. Trying to guess how to balance the load, can be very irritating and annoying, and if the users suffer from impaired vision or a complete loss of sight, they may not be able to correct this imbalance themselves and they will have to wait until someone can assist them. Also, it is not good for the life of the electrical motor to be turned on and off repeatedly.
SUMMARY OF THE INVENTION
The present invention provides apparatus in a top loading automatic clothes washing machine for permitting an operator to determine the location of an imbalance in the load, which may cause the washing machine to malfunction. The invention includes a solution to this problem by providing means inside the washing machine which respond to improper rotation of the clothes basket during the spin/spin-dry cycles, and provide an indication to the operator where the load is unbalanced. The operator can then rearrange the clothes and permit the washing operation to proceed properly.
Many patents deal with the problem of load imbalance in top loading automatic clothes washing machines, but they only provide apparatus to shut down the machine by cutting off power, when a significant imbalance occurs. However, none provides information about the imbalance itself, so that it can be easily corrected, particularly by a visually handicapped person.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view, partly in section, of a closed washing machine embodying the invention;
FIG. 2 is a side sectional view of a portion of the apparatus of FIG. 1;
FIG. 3 is a top view of a portion of the apparatus of FIG. 1; and
FIG. 4 is a perspective view of the invention.
DESCRIPTION OF THE INVENTION
A top loading automatic clothes washing machine 21 embodying the invention includes an outer frame 1, an inner tub 2, and within the tub 2, an inner basket 4, which receives clothes to be washed. Within the basket 4 is the agitator 7, which keeps all of the items constantly moving and tumbling during the wash and rinse cycles. The tub 2 is secured to a lower horizontal platform 19, which contains the main working parts of the machine such as a waterpump, a transmission-motor assembly, a clutch assembly, and other apparatus as required. The platform 19 is suspended by a plurality of suspension legs 9 from the top of the side frames of the machine frame 1.
According to the invention, means are provided which operate when an unbalanced load causes wobbling of the clothes basket 4 and agitator 7, and which provide an indication of the location of the imbalance to the operator. These means include a FIXED GUIDE RING 5, which is positioned just underneath the frame top 17 and tub cover 8. The diameter of the FIXED GUIDE RING 5 is equal to the diameter of the circular top lid opening of the tub 2. The FIXED GUIDE RING 5 is held in a fixed position and is secured to the top center of the four side frames of the cabinet 1, by means of four rod-like GUIDE RING SUPPORTS 3, 90 degrees apart. Each GUIDE RING SUPPORT 3 is fastened on one side to the FIXED GUIDE RING 5, extending laterally from the circumference of the FIXED GUIDE RING 5, then rising vertically and passing through a CIRCULAR OPENING 20 in the tub cover 8. The other side of the GUIDE RING SUPPORT 3 is fastened to the top center of the side frame, thus holding the FIXED GUIDE RING 5 in a fixed position. Each GUIDE RING SUPPORT 3 is constructed of two L-shaped pieces which are joined together with a disconnectable COUPLING 10 in the vertical part above the FLEXIBLE MOISTURE SHIELD 11 and CIRCULAR OPENING 20 in the tub cover 8. This allows the tub cover 8 to be separated from the FIXED GUIDE RING 5 and to be removed from the washing machine, if necessary. The CIRCULAR OPENING 20 in the tub cover 8, where the four GUIDE RING SUPPORTS 3 of the FIXED GUIDE RING 5 pass through, must be sufficiently large to allow enough space for the GUIDE RING SUPPORTS 3 (which remain stationary) when the tub cover 8, tub 2 and basket 4 shift during an unbalanced load. FLEXIBLE MOISTURE SHIELDS 11 are provided and secured to the GUIDE RING SUPPORTS 3 below the COUPLINGS 10 and to the top of the CIRCULAR OPENING 20 in the tub cover 8 to prevent moisture or water to rise above the tub cover 8 during the washing machine operation. To the inside top of the clothes basket are attached six TELESCOPING INDICATORS 6, 60 degrees apart (FIG. 1, 2, 3 and 4). The other end of the TELESCOPING INDICATORS 6 will be in the shape of a C-SHAPED HOOK 14, and will ride around on the inside of the FIXED GUIDE RING 5 (FIG. 1, 2, 3 and 4). Each TELESCOPING INDICATOR 6 (FIG. 2) includes a FIXED TUBE 12 secured to the top of the inner wall of the clothes basket 4 and has an open end distal to the wall of the clothes basket 4. A hollow SLEEVE 13 having an open end is positioned inside the FIXED TUBE 12 and a C-SHAPED HOOK 14 is slidably disposed within the SLEEVE 13 and engages the FIXED GUIDE RING 5. The outer surface of the C-SHAPED HOOK TELESCOPING INDICATOR 6 carries an ANNULAR STOP 15 which is adapted to strike the open end of the SLEEVE 13, and limits the movement of the C-SHAPED HOOK 14 into the SLEEVE 13. The six TELESCOPING INDICATORS 6 will be divided into three pairs. Each pair will have its own color; similarly colored TELESCOPING INDICATORS 6 are to be secured diametrically opposite each other, 180 degrees apart (FIG. 2, 3 and 4). The colors could be red, blue and yellow, and each of the above colored TELESCOPING INDICATORS 6 will have RAISED DOTS 16 (as in Braille), for instance: red TELESCOPING INDICATORS 6 one dot, blue will have two, and yellow three dots. Having RAISED DOTS 16 on the colored TELESCOPING INDICATORS 6 will be very useful to a person who suffers from color blindness, impaired vision or a complete loss of sight. The TELESCOPING INDICATORS 6 can be identified by sight (seeing the color or the RAISED DOTS 16) or by touch (feeling the RAISED DOTS 16), enabling one to balance the load or have the imbalance reduced to an acceptable level.
When the washing machine goes into one of its spin cycles, and the load is unbalanced, the pivot point of the agitator and clothes basket will not be fixed or stationary. The pivot point will move into the direction where the unbalanced load in the clothes basket is located. Since the basket is spinning and is attached via the clutch assembly, transmission, etc. to the platform, this will cause the platform to rotate and if the imbalance is sufficient, to come into contact with the inside of the washing machine frame, resulting in a banging noise and possible movement of the washing machine across the floor. The weight of the unbalanced load will determine the distance the pivot point of the basket and agitator will shift. This distance is equal to the radius of a circle that this pivot point will rotate. When the pivot point shifts, the platform to which all of the forementioned parts are attached, will also shift, including the colored telescoping indicator(s), which are attached to the top inside of the basket. Due to this shift, the C-shaped hook end of the colored telescoping indicators which ride around inside the fixed guide ring will be engaged and pulled out by the fixed guide ring, causing the sleeve to slide out of the fixed tube. Thus the colored indicator(s) will be extended. If the imbalance is sufficient and requires that the washing machine be stopped, one or more colored extended telescoping indicators will show the user where the unbalanced part of the load is. Some of the load must then be repositioned to the opposite side of the basket where the colored indicator of similar color is located. If more than one is extended, the one that is extended most will indicate where the heavier part of the unbalanced load is. If none of the indicators are visibly extended on the washing machine where the back part of the top lid opening is straight, the user can feel underneath the straight part of the opening if any indicators are extended. Then reposition the load as explained above.
After adjusting the load, all the indicators must be recessed or pushed all the way in (FIG. 2 and 4), before restarting the washing machine, so that any further imbalance will be indicated, if the washing machine has to be stopped again. This procedure will be repeated until the imbalance has been reduced to a minimal or tolerable level.
The fixed guide ring assembly with telescoping load imbalance indicators is simple in its construction and should be inexpensive to manufacture and install. It will allow the user of a top loading automatic washing machine to operate it more efficiently when an unbalanced load occurs.
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The disclosure is of washing machine apparatus including a ring, within the clothes basket, and imbalance indicators coupled thereto and adapted to provide a visual indication to an operator when an imbalance occurs and provides problems in the spin cycles. The indicators show the operator where the imbalance is located and it can be easily corrected.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a ball bearing cage, to a ball bearing comprising such a cage, and to a process for assembling such a bearing.
2. Description of the Related Art
In the domain of ball bearings, so-called “rigid” bearings are known, comprising a single row of balls arranged between two so-called “inner” and outer” rings, and allowing a relative movement of rotation of the inner ring with respect to the outer ring without pivoting about an axis perpendicular to the central axis of the bearing. U.S. Pat. No. 5,015,105 describes a ring-shaped cage that may be used with such bearings.
It is also known to equip such a bearing with a cage for separating the balls, such a cage defining recesses in which the balls are received, separated from one another. Such a cage is formed by two elements assembled by fastening, riveting or clipping and requiring high-precision machinings, in order not to increase friction in the bearing too greatly. The necessity of producing such a cage in two parts results from the fact that the cage must be maintained in place in the internal space of the bearing defined between the two rings, failing which it might be driven outside this space.
The different known means for assembling the two parts of a cage most often lead to an increase in the dimensions of the joints between these two parts. For example, when rivets are used, a certain quantity of matter must be provided around each rivet, in order to reduce the risks of rupture of the cage. This leads to relatively large gaps for separation between two adjacent balls and the fact that a bearing equipped with such a cage generally cannot be subjected to an intense load.
In order to allow a maximum load capacity of a bearing, it is also known to manufacture cage-less bearings which are filled with contiguous balls, this solution leads to friction between the balls, which friction may generate considerable wear of the balls, in particular when ceramic balls are used. This solution also involves a risk of the balls escaping from the internal space of the bearing as they are not maintained in place.
As it is necessary to provide a zone for positioning the balls between the rings, the balls can be driven outwardly through this sone, when the bearing is being used.
Finally, EP-A-0 288 334 discloses producing a bearing cage from a flexible band, this cage being provided with a slot which constitutes a zone of weakness of the cage that may lead to deformations likely to release the balls, particularly in the event of axial vibrations of the bearing.
It is a particular object of the present invention to overcome these drawbacks by proposing a novel bearing cage which said cage open on a second side of said cage. avoids friction between the balls and ensures that they are held in the internal volume of a bearing without requiring complex or high-precision assembly.
SUMMARY OF THE INVENTION
To that end, the invention relates to a ball bearing cage in the form of a ring obtained by machining or casting, defining recesses for receiving balls in one row and intended to be interposed between an inner ring and an outer ring of a bearing, characterized in that the recesses are distributed in two groups, each recess of the first group having an opening for positioning a ball located on a first side of the cage, while each recess of the second group has an opening for positioning a ball located on a second side of the cage, opposite the first side.
Thanks to the invention, the cage performs its role of separation of the balls efficiently and enables them to be maintained in position in the internal volume of the bearing as the balls introduced in the recesses of the second group are, to some extent, mounted in opposition with respect to the balls of the first group and act as members for maintaining the cage in the internal volume of the bearing, without requiring complex means for connecting two parts of a cage. The cage of the invention does not necessitate reserving a large volume for assembling two parts, which allows a high density of balls to be implanted, the number of balls of a bearing of given diameter being close to that of a cage-less bearing, which allows a bearing equipped with a cage according to the invention to be used under a high load.
According to advantageous aspects of the invention, the cage incorporates one or more of the following characteristics:
Each recess is defined between two arms and a bottom, the arms extending, when the cage is in configuration mounted in a bearing, in a direction substantially parallel to an axis of rotation of the bearing, while the bottom is substantially perpendicular to this axis. Certain of the arms define two adjacent recesses belonging to the same group of recesses, these arms each comprising a first end adjacent the respective bottoms of the adjacent recesses and a second free end. Certain other arms define two adjacent recesses belonging to the afore-mentioned two groups of recesses, these arms comprising a first end adjacent the bottom of one of the two adjacent recesses and a second end adjacent the bottom of the other adjacent recess. The bottom of the recesses of a group of recesses is pierced with an orifice for passage of a member for extracting balls in place in these recesses. The arms separating the recesses each form two concave surfaces oriented towards two adjacent recesses and adapted to cooperate with the outer surface of the balls. The first group of recesses comprises all the recesses except two, while the second group comprises two diametrally opposite recesses. The cage is cast or machined in one piece, of metal or a composite material.
The invention also relates to a ball bearing comprising a single row of balls, disposed between an inner ring and an outer ring, and a cage such as described hereinbefore.
Such a bearing is easier to assemble than a bearing with cage of the prior state of the art, while its cost is lower and it can operate under a greater load.
In addition, at least one of the rings may be provided with at least one notch for introduction of the balls in an internal volume defined between races formed respectively on the inner and outer rings.
Finally, the invention relates to a process for assembling a ball bearing which comprises a single row of balls, disposed between an inner ring and an outer ring, and a cage defining recesses for receiving the balls, in which process balls are introduced in a volume defined between races formed respectively on the inner and outer rings. This process is characterized in that it comprises the following steps of:
introducing in the afore-mentioned internal volume and via at least one notch made on one side of the bearing, a number of balls less than the nominal number of balls of the bearing, positioning the cage by causing the balls, already in place in the volume, to penetrate in recesses in the cage open on a first side of the cage, and introducing, via the or each afore-mentioned notch, a ball in at least one recess of the cage open on a second side of the cage.
The introduction of the or each ball in the or each recess open on the second side of the cage makes it possible to maintain the cage in position in the internal volume of the bearing without necessitating the use of blocking members or added parts.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more readily understood on reading the following description of an embodiment of a cage and a bearing in accordance with its principle, given solely by way of example and made with reference to the accompanying drawings, in which:
FIG. 1 is a view in perspective of a bearing cage according to the invention.
FIG. 2 is a side view on a smaller scale of the cage of FIG. 1 .
FIG. 3 is a section along line III—III of FIG. 2 .
FIG. 4 is a view on a larger scale of detail IV in FIG. 3 .
FIG. 5 is a view in perspective with parts torn away of a ball bearing according to the invention.
FIG. 6 is a view similar to FIG. 5 , the bearing being seen from the opposite side, and
FIG. 7 is an exploded view in perspective of the bearing of FIGS. 5 and 6 , from the same side as FIG. 6 .
DESCRIPTION OF PREFERRED EMBODIMENT
Referring now to the drawings, the cage 1 according to the invention is obtained by machining steel. The ring 1 might equally well be cast. It is a rigid structure which enables balls to be efficiently maintained in position, including in the event of vibrations of the bearing in which it is mounted.
The ring 1 is centred about an axis X 1 —X′ 1 and comprises two arcs 11 and 12 from which arms 13 substantially parallel to axis X 1 —X′ 1 extend. Arms 14 extend from the ends 11 a , 11 b , 12 a and 12 b of the arcs 11 and 12 . The arms 14 are connected, opposite arcs 11 and 12 , by bridges 15 and 16 . The elements 11 , 12 , 15 and 16 are substantially perpendicular to axis X 1 —X′ 1 .
13 a and 14 a respectively denote the ends of the arms 13 and 14 connected to the arcs 11 and 12 . 13 b and 14 b respectively denote the ends of the arms 13 and 14 opposite the ends 13 a and 14 a . The ends 13 b are free, i.e. are not joined to an arc, while ends 14 b of arms 14 are joined to the bridges 15 and 16 .
The bridges 15 and 16 are each pierced with an orifice 17 , 18 , respectively, in their central part.
Recesses 20 are defined between the arms 13 and 14 . More specifically, recesses 20 1 belonging to a first group I of recesses are formed between two adjacent arms 13 or between an arm 13 and an arm 14 and their respective bottoms are constituted by one of the arcs 11 or 12 . The opening 21 1 of each recess 20 1 of this first group faces upwardly in FIG. 1 .
In the example shown, the cage 1 comprises two series of three recesses 10 1 defined opposite the arcs 11 and 12 .
Two recesses 20 2 belonging to a second group II of recesses, are defined between two arms 14 and their respective bottoms are constituted by the bridges 15 and 16 . The openings 21 2 of these recesses are oriented downwardly in FIG. 1 , i.e. contrary to the openings 21 1 of the recesses of the first group I.
A denotes the side of the cage 1 visible from underneath in FIG. 1 and on the right of FIG. 3 . The respective openings 21 2 of the recesses 20 2 open out on side A of the cage 1 .
B denotes the side of the cage 1 by which it is seen in FIG. 2 ; this side is opposite side A. The respective openings 21 1 of the recesses 20 1 open out on this side B.
The lateral faces 13 c and 14 c of the arms 13 and 14 are concave, with a radius of curvature greater than or equal to the radius of the balls 100 intended to be introduced in the recesses 20 through the openings 21 1 , 21 2 .
The bottoms of the recesses 20 are also concave, as will be seen in FIG. 4 . Towards a recess 20 2 , the bridge 15 presents a concave surface 15 c with, in transverse section, the shape of an open V allowing partial engagement of a ball.
The situation is similar concerning the arcs 11 and 12 and the bridge 16 of which the surfaces 11 c , 12 c and 16 c are also concave at the level of the bottoms of the recesses 20 .
As is more particularly visible in FIGS. 5 to 7 , a bearing 101 according to the invention comprises an inner ring 102 and an outer ring 103 centred on an axis X 2 —X′ 2 which is the axis of rotation of the bearing. When the bearing is in mounted configuration shown in FIGS. 5 and 6 , the axes X 1 —X′ 1 and X 2 —X′ 2 merge.
The inner ring 102 defines a race 102 a for balls 100 , this race 102 a being formed by the outer radial surface of the ring 102 . The inner radial surface of the ring 103 also defines a race 103 a for balls 100 . V denotes the internal volume of the bearing 101 included between races 102 a and 103 a . A′ denotes the side of the bearing 101 shown on the left-hand side of FIGS. 6 and 7 and B′ the side of this bearing shown on the left-hand side of FIG. 5 .
On side A′ of the bearing, the rings 102 and 103 are each provided with a notch 102 b , 103 b allowing the successive introduction of the balls 100 in the volume V, as represented by arrow F 1 in FIG. 7 .
When the bearing 101 is to be assembled, six balls 100 are introduced in the volume V, via the opening made at the level of the notches 102 b and 103 b . The cage 1 is then introduced in the bearing 101 , as represented by arrow F 2 , the balls 100 being distributed in the six recesses 20 1 of the first group I of recesses 20 .
A ball 100 ′ is then positioned, via side A′ of the bearing, in the recess 20 2 shown in the upper part of FIG. 7 , this being represented by the arrow F 3 . The cage 1 is then rotated about axes X 1 —X′ 1 and X 2 —X′ 2 . The angle of rotation of the cage is about 180°, which makes it possible to bring the second recess 10 2 of the second group II opposite the notches 102 b and 103 b and to introduce a second ball 100 ″ in this notch as represented by arrow F 4 . It is then possible to impart to the ring 1 a fresh movement of rotation in order to move ball 100 ″ away from the notches 102 b and 103 b.
Due to the positioning of the balls 100 ′ and 100 ″, the cage 1 is maintained in position in the volume V and efficiently performs its function of separation and distribution of the efforts between the balls 100 , 100 ′ and 100 ″ without it being necessary to add a blocking piece on this cage.
When the bearing 101 is to be dismantled, the balls 100 ′ and 100 ″ are driven from the recesses 20 2 by bringing these recesses successively opposite the notches 102 b and 103 b and by exerting a thrust on the balls by means of a rod 200 passing through an orifice 17 or 18 , as schematically represented by arrow F 5 in FIG. 5 .
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A ball bearing which includes a cage which defines recesses for receiving balls in a single row. The cage is in the form of a ring obtained by casting or machining and is intended to be interposed between an inner ring and an outer ring of the bearing. The cage includes recesses of a first group each having an opening for positioning a ball located on a first side of the cage, while recesses of a second group each have an opening for positioning a ball located on a second side of the cage, opposite the first side.
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BACKGROUND AND SUMMARY OF THE INVENTION
The invention is an improved device for transporting loads between various elevations and in particular to transporting handicapped persons in wheelchairs. Specifically, it relates to an improved device that serves a dual mission, first as a regular stairway facility for ambulatory persons, and second as a ramp-like or ramp-type facility for wheeled vehicles carrying a person or persons, or a load of freight or materials, or other similar loads. The combination stairway and ramp facility being the means by which the aforementioned loads may be moved from the level of one elevation to the level of another elevation.
Such loads in wheeled vehicles might be handicapped persons in wheelchairs, groups of people in wheeled people carriers, packaged freight or materials in wheeled truck means, or other similar loads in suitable wheeled vehicles.
The movement of such loads from one elevation to another elevation may be either an ascending movement or a descending movement.
Devices for moving the aforementioned loads between various elevations in the prior art usually consisted of elevators running vertically in a shaft-like enclosure between the various elevations or the equivalent of such vertical elevators running openly or within some restriction that might be termed an inclined elevator means. The prior art elevators running in vertical shaft-like enclosures are well known. Except for the ordinary escalator, or moving stairway, the prior art inclined elevator means are not as well known.
Some of the prior art inclined elevator means are: an inclined elevator means mounted on and along the protruding edges or nose of the treads of a stairway to one side of the stairway walking area, providing a seat or platform on which a person sits or stands while being moved; a construction type elevator having a framework set at an incline between a ground level elevation and some higher elevation, such as a roof and having a box-like corner for transporting a load from one level to the other; and an inclined set of tracks on and to which a horizontal platform is moveably affixed to ride along the tracks as a load on the horizontal platform is moved from one elevation to another by motive power means. None of these concepts of the prior art provide the novel and unique structure of the present invention for moving wheeled loads from one elevation to another.
Other prior art devices for moving wheelchairs from one elevation to another elevation are described hereinafter, usually described as stair-climbing wheelchairs.
Such stair-climbing wheelchairs consist of wheelchairs having various means affixed thereto to propel the wheelchair up the series of steps, some of which are: a tri-set of wheels rotatably at the back of the chair and a cross-type structure of small rollers at the front of the wheelchair which together drive the combination to climb the stairway; a track-like device affixed at the bottom of a wheelchair which crawls up the stairway; a set of four wheels on vertically movable supports on each side of a wheelchair with the four wheels on each side operating to individually, as a left and right pair, mount the stairs in turn while maintaining the wheelchair level; a similar device to the latter with three pairs of driving wheels on each side of the wheelchair; a track-type device which lays the track on individual treads of a stairway one after the other; and a plurality of wheels in a star-like configuration inside of a track-means that crawls up a stairway step by step.
None of the so-called stair-climbing wheelchairs of the prior art provides the novel and unique structure of the present invention for safely moving a wheelchair or other type of wheeled vehicle, as described hereinafter, from one elevation to another elevation.
The improved device of the present invention consists of a plurality of stairway treads and a plurality of stairway risers set in a first configuration of an ordinary stairway which may be used by ambulatory persons. In a second configuration the plurality of treads and the plurality of risers are stretched out, as hereinafter described, to form a straight ramp-like means up or down which wheeled vehicles, as hereinbefore described, may be moved from one elevation to another elevation.
The plurality of stairway treads and the plurality of stairway risers are suitably hinged together so that they may be stretched out into the aforementioned ramp-like means. The plurality of hinge means are each located so as to hinge the bottom or lower horizontal edge of each riser to the back or inside the horizontal edge of each riser; and the top or upper horizontal edge of each riser to the front or nose of each tread; thus providing the basic ramp-like surface when stretched out.
The top horizontal edge of the uppermost riser is similarly hinged to the horizontal front or nose of the upper landing or platform of the stairway. The bottom horizontal edge of the lowermost riser is arranged to feather-edge with the lower landing or floor when stretched into the said ramp-like configuration.
At each side of each hinge of the plurality of hinges a hinge pin-like extension protrudes beyond the sides of each riser and tread hinged combination. These hinge pin-like extensions slidably fit into slots, described hereinafter, for support of the risers and treads and for control of the movement of the combination of hinged risers and treads when changing from a stairway configuration to a ramp-like configuration or when reversing that movement.
A plurality of slots at each side of the stairway are provided in the stairway side enclosure means. The hinge pin-like extensions extend into and slidably fit in the respective slots at each hinge pin-like extension location.
The aforementioned slots provide the control of movement of the hinge pin-like extensions when the stairway configuration is changed to a ramp-like configuration or a reverse movement is made. The control of movement includes controlling the direction of movement as described hereinafter.
The aforementioned slots are so located and configured so that as the hinge pin-like extensions slidably move therein, the risers and treads are brought into the ramp-like configuration.
The slot for each hinge pin-like extension at the nose of each tread is straight and horizontal, thus the nose of the tread moves forward in a straight line. The slot for each hinge pin-like extension at the bottom of each riser rises in a gentle forward arc-like curve upwardly.
Thus, when moving into a ramp-like configuration, the nose of each tread, with the top of the adjacent riser hinged to it, moves horizontally straight outwardly to a point where the hinged joint will lie in the plane of the ramp-like surface.
Concurrently, the bottom of each riser, with the rear edge of the adjacent tread hinged to it, moves in the gentle arc of the slot to a point where this hinged joint will also lie in the plane of the ramp-like surface.
When the movement is reversed the hinge pin-like extensions follow the control slots to their original position to return the ramp-like configuration to that of a stairway.
At the lower elevation of the dual use device, as a stairway configuration and as a ramp-like configuration, a contact member is provided which is temporarily and removably affixed to the load vehicle to be elevated. The contact member is suitably hinged at one end thereof so that it can be raised to provide access to the stairway of the stairway configuration when a person desires to walk up or down the stairs.
Two power means and associated mechanisms are provided as part of the structure of the invention. A first power means is connected to a mechanism that changes the stairway configuration to a ramp-like configuration, and to reverse the operation. A second power means operates the contact member, after it is temporarily and removably affixed to the load vehicle, so as to push the load vehicle up the ramp-like surface from the lower elevation to the upper elevation; the contact member when reversed will lead the load vehicle or permit the load vehicle to move down the ramp-like surface by gravity.
It is, therefore, an object of this invention to provide a device to move wheeled vehicles from one elevation to another elevation.
It is another object of this invention to provide a device to move wheeled vehicles from one elevation to another elevation that may be operated in a stairway configuration or in a ramp-like configuration.
It is also an object of this invention to provide a device to move wheeled vehicles from one elevation to another elevation wherein the wheeled vehicle is a wheelchair.
It is still another object of this invention to provide a device to move wheeled vehicles from one elevation to another elevation wherein the wheeled vehicle is a people carrier.
It is yet another object of this invention to provide a device to move wheeled vehicles from one elevation to another elevation wherein the wheeled vehicle is a cargo carrier.
It is yet a further object of this invention to provide a device to move wheeled vehicles from one elevation to another elevation that will move the wheeled vehicles loaded or unloaded in an ascending or descending mode between elevations.
Further objects and advantages of the invention will become more apparent in light of the following description of the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial cross-section of a plan view of a device for transporting loads between various elevations, shown in a stairway configuration;
FIG. 2 is a partial cross-section of the device of FIG. 1, shown in a ramp-like elevation;
FIG. 3 is an enlarged cross-sectional view taken on line 3--3 of FIG. 1;
FIG. 4 is an enlarged cross-sectional view taken on line 4--4 of FIG. 2;
FIG. 5 is a cross-sectional view taken on line 5--5 of FIG. 1;
FIG. 6 is an enlarged partial cross-sectional view showing a second embodiment of a portion of FIG. 1;
FIG. 7 is an enlarged cross-sectional view of a third embodiment of FIG. 2; and
FIG. 8 is a mechanism for converting the device for transporting loads in FIG. 1 to the device for transporting loads in FIG. 2 and vice versa.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings and particularly to FIGS. 1, 2, 3, and 4, a device for transporting loads between various elevations is shown at 10.
The device for transporting loads 10 between various elevations is shown in a stairway configuration in FIGS. 1 and 3 and in a ramp-like configuration in FIGS. 2 and 4.
The stairway configuration in FIGS. 1 and 3, described in detail hereinafter, provide a means for ambulatory persons individually, or carrying light loads, to ascent the stairway configuration from a lower elevation 12 to an upper elevation 14, or to descend from an upper elevation 14 to a lower elevation 12.
The ramp-like configuration in FIGS. 2 and 4, described in detail hereinafter, provide a means for transporting loads in wheeled vehicles over the ramp-like configuration from a lower elevation 12 to an upper elevation 14, or from an upper elevation 14 to a lower elevation 12.
The lower elevation 12 and the upper elevation 13 may be of such structure as the floors in a building.
The device for transporting loads 10 between various elevations is suitably enclosed at the sides 16 and 18. Such enclosure sides 16 and 18 may be walls of the general structure in which the device for transporting loads 10 between the afore-mentioned elevations.
Where the enclosed sides 16 and 18 are walls of the general structure, the mechanisms, described in detail hereinafter, are suitably located within such walls. Where the enclosed sides 16 and 18 are mechanism enclosures of the device for transporting loads 10, the enclosured sides 16 and 18 serve a safety purpose to prevent persons or loads falling from the sides. In the latter case the enclosured sides 16 and 18 may be configured similar to low banister walls such as enclose free-standing or open stairways.
A partition or exterior wall 20 is shown at elevation 14 for illustration. However, it is to be understood that the location of the device for transporting loads 10 will determine the relative relationship of other walls or objects. The upper edge 22 of the device for transporting loads 10 should have adequate clearance from any wall 20 so that loads on wheeled vehicles, described hereinbefore and further described hereinafter, may have sufficient space in which to maneuver upon arriving at the upper level 14, or for maneuvering prior to descending to the lower level 12. Thus the upper edge 22 should be adequately spaced from any wall 22 or other similar object of the general structure.
FIGS. 1 and 3 show the device for transporting loads 10 in a stairway configuration. The stairway configuration 24 has a plurality of treads 26 and a plurality of risers 28.
FIGS. 2 and 4 show the device for transporting loads 10 in a ramp-like configuration 30. The plurality of treads 26 and the plurality of risers 28 of the stairway configuration 24 are now in line in the plane of the surface of the ramp-like configuration 30. Thus, the treads 26 and the risers 28 alternate in the plane of ramp-like surface 30.
In FIG. 3 showing the stairway configuration 24, the ramp-like configuration 30 is shown in phantom lines for treads 26 and risers 28.
In FIG. 4 showing the ramp-like configuration 30, the stairway configuration 24 is shown in phantom lines for treads 26 and risers 28.
The manner in which the plurality of treads 26 and the plurality of risers 28 is moved from the stairway configuration 24 to the ramp-like configuration 30 is described hereinafter. However, it will be noted in FIG. 4 that at the bottom of the ramp-like configuration 30 at the elevation 12 that the bottom or lowest riser 28 of the stairway configuration 24 is placed in a position 32. This requires a filler tread 34 to complete the ramp-like configuration 30. The filler tread 34 is shown in the stairway configuration 24 in FIG. 3.
To prevent the leading edge or nose 36 of the filler tread 34 from presenting a safety hazard, the leading edge or nose 36 may be tapered or provided with a feather edge. However, a preferred second embodiment is to suitably affix the leading edge or nose 36 to a plurality of narrow slat-like members 38 which has a top surface that is in the same plane as the elevation 12. The arrangement and operation of these narrow slat-like members 38 is described hereinafter and is shown in FIG. 6.
When the filler tread 34 with the tapered or feathered edge 36 is used, provision must be made for a depressed area 40, within the area of the lower elevation 12, within which the filler tread 34 moves when the airway configuration 24 is extended into a ramp-like configuration 30.
The end 42 of the depressed area 40 is spaced from the tapered or feathered edge 36 when the device for transporting loads 10 is in the stairway configuration 24, as shown in FIG. 1. When the device for transporting loads 10 is in the ramp-like configuration 30 the tapered or feather edge 36 interfaces with and coincides with the end 42 of the depressed area 40 as shown in FIG. 2.
It is to be noted that the depressed area 40 is within the confines of the enclosed sides 16 and 18. This provides a measure of safety where end 42 of the depressed area 40 must also be tapered or given a feathered edge to prevent exposure to a safety hazard when the device for transporting loads 10 is in either the stairway configuration 24 or the ramp-like configuration 30.
In the second embodiment for the lower end of the ramp-like configuration 30, using the plurality of narrow slat-like members 38, shown in FIG. 6, the narrow slat-like members 38 are situated within the depressed area 40 so that the top surface of the filler tread 34, the top surface of the plurality of narrow slat-like members 38, and the top surface of elevation 12 are substantially in the same horizontal plane.
A transition plate 44 with feathered edges provides the means whereby the narrow slat-like members 38 are moved away as the nose 36 of the filler tread 34 moves into its bottom position as part of the ramp-like configuration 30. It is to be noted that in this second embodiment the nose 36 shown in FIG. 6 is not tapered or feathered as in the first embodiment shown in FIG. 1, but is so constructed so that the top surface of the filler tread 34 is flush with, and adjacent to, the top surface of the first of the narrow slat-like members 38.
When the stairway configuration 24 is moved and converted into a ramp-like configuration 30, the plurality of narrow slat-like members 38, hingedly 46 affixed to each other and hingedly 46 affixed to the leading edge or nose 36 of the filler tread 34, all move toward the end 42 of the depressed area 40. The narrow slat-like members 38 each, in turn, pass under the transition plate 44 and then downwardly. The narrow slat-like members 38 may be stored temporarily in numerous ways after passing under the transition plate 44 and then downwardly, all of which are within the scope and intent of this invention.
The narrow slat-like members 38, after passing under the transition plate 44, move over a drum-like roller 48 and then downwardly. The plurality of narrow slat-like members 38 may be permitted to hang straight downwardly within a slot at enclosure 50, as shown in phantom lines 52, or the distal end narrow slot-like member 54 may be affixed to a reel-like device 56. Other means of temporarily storing the plurality of narrow slat-like members 38 may be used and such variations are within the scope and intent of this invention.
It is to be understood that to have the lowermost transverse edge of the bottom riser 28 move straight outwardly in a horizontal direction to the lowermost point of the ramp-like configuration 30, thus establishing a slightly steeper ramp configuration 30, and eliminating the filler tread 34, is within the scope and intent of this invention. In such a structure the narrow slat-like members 38 are hingedly affixed to the lowermost transverse edge of the bottom riser 28 in a manner similar to the manner in which the slat-like members 38 were hingedly affixed to the leading edge or nose 36 of the filler tread 34 as shown in FIG. 7.
It is also to be understood that as a further variation, the lowermost transverse edge of the bottom riser 28 may be moved horizontally paralled with the plane of the elevation 12 without resort to the use of a depressed area 40 and the narrow slat-like members 38. In this latter arrangement, the lowermost transverse edge of the bottom riser 28 is tapered to a feather edge on the so called inside of the riser 28 so as to provide an easy transition from the elevation 12 to the ramp-like configuration 30.
It is to be noted that in FIGS. 1, 2, 3, 4, and 5, five risers 28 and four treads 26, exclusive of the filler tread 34 and upper landing of elevation 14, are shown for illustration of the device for transporting loads 10. It is to be understood that the range of the plurality of treads 26 and risers 28 is unlimited in order to match and facilitate difference in elevations between the lower elevation 12 and the upper elevation 14. Such an unlimited range in the plurality of treads 26 and risers 28 is within scope and intent of this invention.
The treads 26 and risers 28 are hingedly 58 affixed to each other. The uppermost riser 28 is similarly hingedly 58 affixed to the elevation 14 landing at the upper edge 22 of the device for transporting loads 10, and to the filler tread 34 or to the narrow slat-like members 38 when so structured.
The hinges 46 and 58 may be piano-type hinges or other similar hinges providing a positive in-line hinged joint that parallel each other in the plurality of hinged joints for positive movement.
The hinges 46 and 58 have extended hinge pins 60 that fit into, are controlled and guided by, and are supported by and within slots 62 and 64. Slots 62 are for the extended hinge pins 60 of and to guide, control, and support the treads 26 when moving from a stairway configuration 24 to a ramp-like configuration 30. Slots 64 are for the extended hinge pins 60 of and to guide, control, and support the risers 28. The extended hinge pins 60 are integral and monolithic with the hinge pin portions within the hinges 46 and 58 and extend outwardly on both sides of the hinges 46 and 58.
The slots 62 are horizontally straight and level in order to guide the nose 66 of each tread to its position in the plane of the ramp-like configuration 30. The slots 64 are in an upturned arc-like configuration which follows the path taken by the extended hinge pins 60 of the risers 28 as they extend and rise concurrently in order to bring the juncture of the lowermost point of each riser 28 with the rearmost point of each tread to its position in the plane of the ramp-like configuration 30.
Note that the upper edge 22 of the device for transporting loads 10 is essentially the nose of the landing or upper level 14 and is similar to the nose 66 of each tread 26, but the upper edge 22 is stationary.
At the bottom of the ramp-like configuration 30 at the elevation 12, the extended hinge pin 60 of the hinge 46 at the forward end of the filler tread 34 follows a similar horizontally straight and level slot 62. This is also the case when the narrow slat-like members 38 are part of the embodiment. If the alternative embodiment is used the lowermost transverse edge of the lowermost or bottom riser 28 is moved horizontally with the plane of the elevation 12, without resort to the use of a depressed area 40 and the slat-like members 38, the lowermost transverse edge of the bottom riser 38 moves in a horizontally straight slot 62, instead of an upturned slot 64. This latter embodiment variation then gives all the other slots 62 and 64 a slightly shorter length as the plane of the ramp-like configuration 30 is at a slightly steeper angle with the elevation 12.
The movement of the extended hinge pins 60 in the respective slots 62 and 64 is by a power means 68 as shown in FIG. 8. The power means 68 transfers or transmits motion to the respective extended hinge pins 60 by a plurality of push-pull rods 70. Note that the length of slots 62 and 64 are each progressively longer in length from the top of the stairway configuration 24, or ramp-like configuration 30, at elevation 14, to the bottom of the stairway configuration 24, or ramp-like configuration 30. Note, also, that the slots 62 and 64 are on each side of the device for transporting loads 10.
The plurality of push-pull rods 70 are progressively longer to match the progressively longer distances that the extended hinge pins 60 must move in the progressively longer slots 62 and 64, respectively, from top to bottom as hereinbefore described, when converting from a stairway configuration 24 to a ramp-like configuration 30, reversing the movement. The plurality of push-pull rods 70 are suitably connected to a common motion lever 71 which in term is suitably connected by a power transmission means 69 to the power means 68.
To assure an even movement in the aforementioned conversion from the stairway configuration 24 to the ramp-like configuration 30, the plurality push-pull rods 70 are provided on both sides of the device for transporting loads 10. It is to be understood, however, that to provide the plurality of push-pull rods 70 on one side only, or by a connection means at the center point, transversely, of each tread 26 and riser 28 in the vicinity of the transverse center point of the hinges 58, is within the scope and intent of this invention.
It is also to be understood, that alternative means for moving the extended hinge pins 60 in the slots 62 and 64, respectively, such as by a solid side plate, pair of side plates, or a center plate, is within the scope and intent of this invention.
Likewise, it is also to be understood that other alternative means for moving the extended hinge pins 60 in the slots 62 and 64, respectively, such as by a train of gears, a plurality of racks and pinions, or by other similar or or equivalent means, so as to move the extended hinge pins 60 within their respective slots 62 and 64, in both timed and dimensional movement, in converting the device for transporting loads from one mode to another mode of configuration, is within the scope and intent of this invention.
In that regard, it is also within the scope and intent of this invention to provide a plurality of power means, instead of a single power means, to provide a synchronized timed and dimentional movement for each tread 26 and riser 28 in connecting the device for transporting loads 10 to the several modes described hereinbefore.
The various alternative power means, described hereinbefore, for converting the device for transporting loads 10 from one mode to another mode are somewhat optional, the primary portion of the invention lying in the mechanism of the detailed description of the stairway configuration 24 and the ramp-like configuration 30, and in the means for moving the aforementioned wheeled loads up the ramp-like configuration 30 as will be described hereinafter.
One simulation of the alternative power means for the conversions is shown in FIG. 5. In FIG. 5 a power source 72 is mechanically transmitted or connected 74 to the alternative mechanism 76 which is shown schematically.
Regarding the stairway configuration 24 and the ramp-like configuration 30, there are three variations or embodiments. FIGS. 1 and 2 show the first embodiment, FIG. 6 shows the second embodiment which modifies the structure of the first embodiment at the elevation 12 level, and FIG. 7, shows the third embodiment which modifies the structure of the first embodiment at the elevation 12 level and also modifies the angle of the ramp-like configuration 30 in relation to the elevations 12 and 14.
The manner in which a wheeled load is moved up or down the ramp-like configuration 30 is by mean of a load push bar 78. The load movement bar 78 removably interfaces with a suitable contact means on the wheeled load and upon operation of the power means 80 pushes the wheeled load up the ramp of the ramp-like configuration 30. In reverse, the movement bar 78 serves as a restraining means to lead the wheeled vehicle down the ramp of the ramp-like configuration 30, the wheeled vehicle actually descending the ramp by gravity.
When the wheeled vehicle is a wheelchair 92, the wheelchair 92 is moved upon down the ramp with the person in the wheelchair facing down the ramp as the preferred method. However, it is to be understood that the wheelchair 92 may be moved up or down the ramp with the person in the wheelchair facing up the ramp, and such a variation is within the scope and intent of the invention.
The wheeled vehicles may be temporarily latched to the wheeled vehicle at the contact means thereon. Such a variation is also within the scope and intent of the invention.
The movement bar 78 is lock-hinged 82 at the side where it is affixed to the mechanism 84 of the power means 80. The lock-hinge 82 permits release and raising the movement bar 78 at the lower level elevation 12 to permit movement of a wheeled vehicle into position for movement up the ramp, or for movement of a wheeled vehicle away from the ramp which has descended the ramp; and at the upper level elevation 14 it permits release and raising the movement bar 78 when the stairway configuration 24 is to be used by ambulatory persons. The lock hinge 82 provides a desirable safety factor.
The movement bar 78, suitably affixed to the mechanism 84 inside the enclosed side 16, moves in a slotlike opening 86 in the enclosed side 16. The slot-like opening 86 parallels the plane of the ramp.
Controls 88 for operation of the power means 68 are located at the elevations 12 and 14. The controls are located conveniently for the person moving the wheeled vehicle or for the person in the wheelchair.
Regarding the power means 80 and the mechanism 84 associated with it, it is to be understood that the mechanism 84 may be belt driven, chain driven, or by any other similar or equivalent means, and that these variations are within the scope and intent of the invention.
As can be readily understood from the foregoing description of the invention, the present structure can be configured in different modes to provide the ability to change a stairway configuration into a ramp-like configuration for moving wheeled vehicles up or down the ramp between several elevations.
Accordingly, modifications and variations to which the invention is susceptible may be practiced without departing from the scope and intent of the appended claims.
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The invention is an improved device for transporting loads between various elevations. Such loads may be handicapped persons in wheelchairs, wheeled truck loads of freight or materials, wheeled people carriers, or other similar loads that require transport from one elevation to another, either ascending or descending. The improved device serves a double mission as a regular stairway facility for ambulatory persons, and as a ramp-type facility for wheeled vehicles carrying a person, or persons, or a load of freight or materials, and other such loads as may require movement from one elevation to another elevation. The improved device for transporting loads between various elevations consists of: a plurality of stairway treads; a plurality of stairway risers; said plurality of stairway treads and plurality of stairway risers being suitably hinged together in alternating sequence so as to be capable of expansion into a ramp-like surface; a plurality of guide slots to control movement of said hinged plurality of stairway treads and stairway risers when moving from a stairway configuration to a ramp-like configuration or the reverse thereof; a plurality of hinge pin-like extensions to connect the hinges, between each stairway tread and each stairway riser, to said plurality of guide slots; a contact member to temporarily affix to a loaded vehicle to be moved; a power means to operate a mechanism to change the stairway configuration to a ramp-like configuration or the reverse; and a power means to operate a mechanism to move the contact member to move said loaded vehicle.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority of European application No. 03013173.4 filed Jun. 11, 2003 and which is incorporated by reference herein in its entirety.
FIELD OF INVENTION
The invention relates to a method for alternately operating a terminal at at least two communication nodes and to a communication arrangement for carrying out the method.
BACKGROUND OF INVENTION
Communication networks usually contain a multiplicity of terminals and a plurality of communication nodes. In circuit switched communication arrangements, for example in ISDN systems, each terminal in this arrangement is permanently registered with a respective communication node (switching center) and is thus permanently associated therewith. In this case, this association is provided by the cabling, so that a terminal, for example a telephone or a fax machine, is registered precisely with that switching center to which this terminal also has a physical connection.
The terminals in voice data networks, frequently also referred to as voice-over-IP networks (VoIP=Voice-over-Internet Protocol), are also permanently associated, and registered, with one of the communication nodes in the respective voice data network. By way of example, such voice data networks use the H.323 protocol (ITU-T-H.323) or the SIP protocol (SIP=Session Initiation Protocol) for signaling. In a voice data network—unlike in circuit switched communication networks—it is basically possible for any network component, that is to say any terminal and any communication node, to interchange data (particularly voice data) with any other network component directly. A fixed association among the network components, as provided in the circuit switched communication networks on the basis of the cabling, is neither imperative nor desirable in voice data networks. The terminals in voice data networks are frequently also referred to as “clients”, because these terminals differ significantly from circuit switched terminals. Thus, by way of example, they may be in the form of a telephone with a network connection or else in the form of a computer with a piece of communication software installed thereon. The communication nodes in the voice data networks are frequently also referred to as “gatekeepers” (H.323) or “proxies” or “SIP proxies” (SIP protocol), since the function of these communication nodes forms not only the connection initiation between the clients but also the access control for transfer devices to other networks, the “gateways”. In the text below, the term “gatekeeper” is used as standard for gatekeeper and (SIP) proxy, in order to simplify matters.
The communication nodes in the voice data networks store configuration data relating to those terminals which are registered with this communication node. These data are, by way of example, information about the authorizations of the respective client or of the user of the respective client, associations with call acceptance groups, the telephone number of the client etc. The communication node (gatekeeper) with which a client is registered is also referred to as the “home node” or “home gatekeeper”. If this client is now intended to be operated at a different communication node, then the corresponding terminal (client) is signed off from the home node and is registered with another communication node, also referred to as the “adoptive gatekeeper” if the change is only temporary. If, following registration, the configuration data stored at the home node are transferred to the “adoptive gatekeeper”, then the terminal can be operated at the adoptive gatekeeper in the same way as at its home node. If this “move” to the adoptive gatekeeper is not just brief (temporary), but rather permanent, then the adoptive gatekeeper now becomes the new home node for the terminal.
Such moves, like the one described above, by terminals from one communication node to another communication node are often prompted in order to ensure an even utilization level (“load balancing”) for the communication nodes in a communication network. Such a move may also be necessary “on an unscheduled basis”, for example if a terminal's home node fails or is no longer obtainable on account of a fault in the communication network. In that case, a substitute communication node, that is to say an adoptive gatekeeper, needs to adopt the function of the original home node either temporarily or permanently.
A drawback which has been found with the known communication networks is that the move by terminals from one communication node to another communication node needs to be controlled manually. Although computer aided tools are known for performing the necessary steps, for example transfer of the configuration data from one communication node to another communication node, automatically on the basis of a manual request, the decision regarding which terminal changes to which communication node at what time needs to be made manually and needs to be input into the system manually. In particular, when changing to the terminal in question or to the terminals in question, the network address of the “new” communication node needs to be added manually. Another drawback is that a merely temporary change of communication node, for example as a result of a fault, also requires the final restoration of the original state, that is to say the move by the terminal back to its original home node, to be initiated and performed manually.
SUMMARY OF INVENTION
The object of the invention is to propose a method which can be used to change terminals between two communication nodes with only little or without any manual involvement, and to propose a communication arrangement in which terminals are changed between communication nodes with as little manual involvement as possible.
The object is achieved by the claims.
For the method, the solution provides that the obtainability of the first communication node is monitored, that in the event of the first communication node being unobtainable a status information item relating to the unobtainability is produced, and that the status information item is taken as a basis for setting up a logical connection between the terminal and the second communication node, and the terminal is automatically operated at the second communication node, which has an associated second address. This ensures that, in the event of the terminal's home communication node being unobtainable, this terminal is operational again in the shortest possible time without this requiring manual inputs.
For the communication arrangement, the solution provides that the communication network contains a management server, that the management server stores a copy of the configuration data required, that the communication network contains a monitoring apparatus which monitors the obtainability of the first communication node, that means are provided for transferring the copy of the configuration data required to a second communication node in the event of the first communication node being unobtainable, so that the terminal is operated at the second communication node in the event of the first communication node being unobtainable. The effect achieved by this arrangement is that the terminal can be operated at the second communication node in the same way as it was operated at the first communication node prior to the change of communication node.
The method is advantageously configured by the characterizing features of dependent patent claims 2 to 13 . In this case, the advantages described for the method also apply in the appropriate context to the arrangement.
If the communication network used is a voice data network, the terminal used is a voice data terminal and if the communication nodes used are gatekeepers, then there is no need for manual alignment of the cabling in the communication network.
A terminal which has changed from the first communication node to the second communication node can continue to be operated with its full functionality if the first communication node stores configuration data which relate to the terminal and are required in order to operate the terminal, and if the configuration data required for operating the terminal at a second communication node are transferred to the second communication node. If this involves the transmission not only of the necessary configuration data but also of extra terminal specific configuration data, then “added service features” of the terminal in question may also continue to be used.
The configuration data for a terminal are not lost even when the first communication node fails completely if the terminal is used to store a copy of the configuration data, and if registration of the terminal with the second communication node is followed by the copy of the configuration data being transferred from the terminal to the second communication node and being used by the second communication node in order to operate the terminal. When the configuration data are stored in the terminal itself in this way, there is also no need for operation of a central database for configuration data in the communication network. When a central database is omitted, it is also possible to dispense with a (central) management server.
In the event of the first communication node being unobtainable, the terminal can change to a second communication node without inquiring with a further entity and hence without any time delay by virtue of the terminal being used to store the second address and by virtue of the terminal using the stored second address to register with the second communication node in the event of the first communication node being unobtainable.
In a communication network having a large number of communication nodes, the probability of successful registration with an adoptive communication node increases by virtue of the communication network containing further communication nodes having a respective dedicated address, the terminal being used to store a sorted list containing the addresses of the communication nodes, and, in the event of the first communication node being unobtainable, the list of communication nodes being processed, as a result of registration attempts by the terminal, until the terminal has registered with one of the communication nodes. If the various communication nodes are equipped with different powers in this case, then the list is ideally sorted according to the power of the communication nodes such that registration with a very powerful communication node is attempted first of all, and if this second communication node is unobtainable then registration with less powerful communication nodes is attempted, with losses of performance being accepted.
It is sufficient to store a single further address in the terminal as a precaution against error situations if the communication network operates a management server which has an address and stores the second address, with the terminal being used to store the address of this management server, the terminal sending a query message to the management server in the event of the first communication node being unobtainable, the management server transmitting the second address to the terminal in a response message, and with the terminal using the transmitted second address to register with the second communication node. This practice also lowers the administrative involvement in the communication network when communication nodes are added or removed.
It is possible to avoid storing configuration data or a copy thereof in the terminal by virtue of the management server being used to store a copy of the configuration data, and, when the terminal has registered with the second communication node, by virtue of the copy of the configuration data being transferred from the management server to the second communication node and being used by the second communication node in order to operate the terminal.
It is possible to avoid configuring a new communication node address in the terminal when the communication node changes if the communication network operates a management server which is used to store a copy of the configuration data and the first address, with the management server monitoring the obtainability of the first communication node, and with the management server transferring the copy of the configuration data and the stored first address to the second communication node in the event of the first communication node being unobtainable. In this case, the second communication node is assigned the first address, and the second communication node uses the received copy of the configuration data for the terminal to perform the function of the first communication node by assigning the first address. In the case of this practice, the programming of the terminal is not affected by the change of communication node.
If the configuration data are used at the first communication node in a first format and at the second communication node in a second format, and the configuration data transferred to the second communication node are converted from the first format into the second format before transfer, it is possible to use communication nodes of different types to operate the terminal.
A change of communication node without influencing the terminal is particularly simple to implement if the communication nodes used are respective communication assemblies in a communication installation of modular design, if the management server used is a control assembly in the communication installation of modular design, and if, when the communication assemblies have been started up, the configuration data and the respective address are respectively transferred from the control assembly to the respective communication assembly.
The original state of the communication network is automatically restored by virtue of the unobtainability of the first communication node being monitored when the terminal is operated at the second communication node and by virtue of the terminal being signed off from the second communication node and registered with the first communication node again when the first communication node is obtainable again.
A separate monitoring entity in the communication network may be dispensed with if the monitoring is performed by the second communication node or by the terminal itself.
When the obtainability of the first communication node has been restored, a fresh change may be prevented if operation of the terminal at the second communication node involves the first communication node being replaced by the second communication node. Hence, the original first communication node now becomes the second communication node.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the inventive method are explained below with reference to the drawings and are used at the same time to explain an exemplary embodiment of the inventive arrangement.
In this case:
FIG. 1 shows a communication network with a data line, a terminal and two communication nodes,
FIG. 2 shows a data network with a data line, a terminal, two communication nodes and a management server,
FIG. 3 shows a communication network with a data line, a terminal and a communication installation of modular design which has two communication assemblies and a control assembly, and
FIG. 4 shows a distributed communication network with a central office, two subsidiaries, a data network, a circuit switched network, two terminals and three communication nodes.
DETAILED DESCRIPTION OF INVENTION
FIG. 1 shows, as a first exemplary embodiment, a communication network which comprises a data line LAN 1 , two communication nodes GK 1 , GK 2 and a terminal EG 1 . The communication network shown also contains other communication nodes and terminals; however, FIG. 1 shows only the network components which are required in order to explain the exemplary embodiment. The communication nodes GK 1 , GK 2 are gatekeepers in a VoIP communication arrangement, and the terminal EG 1 is a voice data terminal, that is to say a VoIP client. The communication nodes GK 1 , GK 2 and the terminal EG 1 interchange data, particularly voice data, with one another via the data line LAN 1 . The data line LAN 1 is part of a packet switched network in which the data are interchanged on the basis of the Internet protocol. In this case, data are combined into “data packets” which are addressed using the address (IP address) of the respective receiver. For this purpose, the communication node GK 1 has an associated first address, the communication node GK 2 has an associated second address, and the terminal EG 1 has an associated terminal address.
The terminal EG 1 is operated at the communication node GK 1 , that is to say it is registered with the communication node GK 1 . The communication node GK 1 stores configuration data relating to the terminal EG 1 . These configuration data include, by way of example, details about the authorization of the terminal EG 1 to conduct external telephone calls, details about group associations and other information. These configuration data are combined at the communication node GK 1 to form a configuration data record, of which a current copy is created at regular intervals of time, this copy respectively being transferred to the terminal EG 1 . A separate memory area in the terminal EG 1 is used to store this copy. If a newly created copy does not differ from the previously created copy which has been transferred, the fresh transfer of the configuration data to the terminal does not occur.
The terminal EG 1 likewise stores a list of all of the communication nodes GK 1 , GK 2 in the communication network which are able to be used by the terminal EG 1 . This list is prioritized, i.e. the communication node GK 1 , which acts as home node, is recorded at the first position in the list, the communication node GK 2 , which is provided as the most suitable substitute communication node, is recorded at the second position, and other communication nodes (not shown in FIG. 1 ) in the communication network are recorded at the other positions in the list.
Among the configuration data, it is possible to distinguish between requisite configuration data and full configuration data. Requisite configuration data are those configuration data which are absolutely necessary in order for a terminal to be able to be operated at a communication node having a basic functionality, that is to say in order to perform a pure telephony function. Full configuration data also comprise those settings and information which are required in order to implement “added service features”, for example for configuring call acceptance groups, personal telephone directories etc. In the present exemplary embodiment, the full configuration data are stored as a copy in the terminal EG 1 .
The terminal EG 1 checks at regular intervals of time whether the communication node GK 1 is obtainable. To this end, the terminal EG 1 is equipped with a monitoring device. If an error occurs at the communication node GK 1 or in the connection between the terminal EG 1 and the communication node GK 1 , the terminal EG 1 detects the error situation “unobtainable”. The terminal EG 1 produces a status information item corresponding to the error situation, and the registration function of the terminal EG 1 attempts to use this status information item to register with a different communication node in the communication network. To this end, the terminal EG 1 calls its stored list of available communication nodes and reads the network address of the prioritized substitute system, namely the communication node GK 2 , from this list. The terminal EG 1 then sends a registration message to the communication node GK 2 . The communication node GK 2 detects that it has sufficient capacity reserves and that the terminal EG 2 is authorized to register with the communication node GK 2 . The communication node GK 2 thus sends a confirmation message to the terminal EG 1 , which, in response, sends the configuration data stored as a copy to the communication node GK 2 . For the purpose of this transmission of configuration data, the terminal EG 1 comprises, as transfer means, a program with communication sub routines in appropriate form. The communication node GK 2 uses the received configuration data for the terminal EG 1 to configure itself in the same way as the communication node GK 1 was configured beforehand.
The communication node GK 2 , for its part, now checks at regular intervals of time whether the communication node GK 1 , whose terminal EG 1 is being managed by it as a “guest”, is operational again and whether the connection to this communication node GK 1 exists again. As soon as this is the case, the communication node GK 2 takes away the authorization to use the communication node GK 2 from the terminal EG 1 , which corresponds to signing off the terminal EG 1 from the communication node GK 2 . As a result, on the basis of the regular checks to determine whether the communication node GK 2 used is obtainable, the terminal EG 1 again detects the error situation “unobtainable” and again starts to find a communication node which can be used on the basis of the stored, sorted (prioritized) list. Since the list entry having the highest priority is the entry for the communication node GK 1 , the terminal EG 1 is again registered with the communication node GK 1 , as a result of which the original state is restored.
Alternatively, the terminal EG 1 itself may also check at regular intervals of time whether the communication node GK 1 or the connection to this communication node GK 1 has been restored, and after the latter has been restored it can sign off from the communication node GK 2 used as a substitute and can register with the communication node GK 1 again.
As an alternative to the restoration of the original state described above, the components of the communication network may also be programmed such that the terminal EG 1 is no longer changed back from the communication node GK 2 to the communication node GK 1 , but rather that the communication node GK 2 now represents the home communication node of the terminal EG 1 , and the original home communication node GK 1 now becomes a substitute communication node having a corresponding priority.
The list which is stored in the terminal EG 1 can also record such communication nodes as have a lower scope of services than the home communication node GK 1 . Although these communication nodes are regularly classified with a low priority in the list, such less powerful communication nodes may also be used in the event of communication nodes with higher priority being unobtainable. In these cases, not all configuration data transferred by the terminal may be used to configure the communication node which is used as a substitute, but rather only those which can be implemented by the spectrum of services at the communication node which is now being used.
FIG. 2 shows, as a second exemplary embodiment, a communication network which is similar to the communication network from FIG. 1 and which is likewise equipped with a data line LAN 2 . The data line LAN 2 connects the terminal EG 2 , the communication nodes GK 3 , GK 4 and the management server VS to one another. In a similar manner to the exemplary embodiment from FIG. 1 , the components of the communication network which is shown here each have associated network addresses.
The terminal EG 2 is operated at the communication node GK 3 . The communication node GK 4 is intended to be used by the terminal EG 2 in those cases in which the communication node GK 3 is unobtainable on account of a fault. To this end, the terminal EG 2 stores the network address of the management server VS.
The communication node GK 4 is arranged as a “passive system” in the communication network. This means that, in the event of there being no faults, the communication node GK 4 is not used by any terminal in the communication network, but rather is reserved merely as a substitute system. Besides the active communication node GK 3 , the communication network may contain a relatively large number of further active communication nodes and also further passive communication nodes; the set of all of the passive communication nodes is also referred to as a “backup pool”.
The management server VS arranged in the communication network comprises a database which stores a copy of the configuration data of all of the active communication nodes GK 3 in the communication network. To this end, data alignment takes place at regular intervals of time between the active communication nodes and the management server VS.
While the terminal EG 2 is registered with its home communication node GK 3 , the terminal EG 2 repeats refreshes its registration with the communication node GK 3 at regular intervals of time. This cyclic repetition of registration is also referred to as “lightweight registration” in voice data communication networks based on the H.323 standard. As soon as such a repeat registration operation is not able to take place on account of a fault on the data line LAN 2 or at the communication node GK 3 , the terminal EG 2 identifies the error situation “unobtainable”, produces a corresponding status information item and sends the latter to the management server VS whose address is stored in the terminal EG 2 . The management server VS now checks whether the communication node GK 3 is actually unobtainable and, if so, determines a substitute communication node, in the present exemplary embodiment the communication node GK 4 . The management server VS now sends the communication node GK 4 the configuration data for the communication node GK 3 which are stored in its database. The communication node GK 4 uses these configuration data to configure itself in the same way as the communication node GK 3 was configured beforehand, and subsequently becomes an active communication node. By sending a test message to the communication node GK 4 , the management server VS detects that it is ready to operate, and sends the terminal EG 2 the network address of the communication node GK 4 . The terminal EG 2 now records the communication node GK 4 as its associated home communication node and registers with this communication node GK 4 .
If the communication node GK 4 offers an identical or even improved scope of services as compared with the communication node GK 3 , then the communication node GK 4 continues to be the active communication node even after the obtainability of the communication node GK 3 has been restored, while the now restored communication node GK 3 becomes a passive, that is to say substitute, communication node. If the communication node GK 4 has a smaller scope of services than the communication node GK 3 , however, then a reduction in functions has arisen when the terminal EG 2 has changed from the communication node GK 3 to the communication node GK 4 . In such cases, the management server VS ensures that, when the obtainability of the communication node GK 3 has been restored, the configuration data for the communication node GK 3 which are stored in the management server VS are again transferred to this restored communication node GK 3 , and the latter readopts its original function. Alternatively, the management server VS may also transmit these configuration data to a different substitute communication node having a corresponding scope of services in the communication network, in order to ensure that the terminal EG 2 is fully functional again.
The management server VS also comprises an alignment unit which is able to convert the format of the configuration data. This is necessary because communication nodes of different types also store the configuration data in different ways. If the configuration data stored as a copy now need to be used with a communication node of another type, the management server VS performs appropriate reconfiguration of the configuration data.
As a result of the transfer of the complete configuration data for the communication node GK 3 which has failed to the communication node GK 4 , all terminals registered with the communication node GK 3 are transferred to the substitute communication node GK 4 , so that even when a large number of terminals are registered the step of transferring configuration data need be performed only once. Hence, if, after the terminal EG 3 , other terminals (not shown) detect the “loss” of their home communication node GK 3 and send a corresponding status information item to the management server VS, then the latter can respond directly using the network address (IP address) of the already configured substitute communication node GK 4 .
FIG. 3 shows, as a third exemplary embodiment, a communication network with a data line LAN 3 to which the terminal EG 3 and the communication installation PBX are connected. The communication installation PBX is a communication installation of modular design in which various assemblies SB, B 1 , B 2 are connected to one another by means of a backplane BP having an electrical data bus. FIG. 3 shows three assemblies SB, B 1 , B 2 in the communication installation PBX, these being the control assembly SB and the communication assemblies B 1 , B 2 . The communication assemblies B 1 , B 2 are used as communication nodes for the terminal EG 3 and other terminals (not shown here) in the communication network. The communication assemblies B 1 , B 2 are respectively connected to the data line LAN 3 .
Besides the voice data communication assemblies B 1 , B 2 , the communication installation PBX also has other assemblies (not shown here) plugged in for the purpose of connecting circuit switched terminals, and also has assemblies for accessing circuit switched communication networks, that is to say gateway assemblies.
The terminal EG 3 is registered with the communication assembly B 1 together with other terminals (not shown here). For the purpose of registration and for ongoing operation, the terminal EG 3 stores the network address of the communication assembly B 1 . The communication assembly B 2 is in passive mode and is reserved in the communication installation PBX as a substitute assembly for the active communication assembly B 1 and other active communication assemblies (not shown here).
The control assembly SB controls the communication assemblies B 1 , B 2 . When one of the communication assemblies B 1 , B 2 is started (“started up”), the necessary operating software is first transferred from the control assembly SB to the respective communication assembly B 1 , B 2 . This operating software is used to start the communication assemblies B 1 , B 2 . When these have been started, the control assembly transfers to the respective communication assembly B 1 , B 2 the configuration data relating to the terminals which are respectively being managed by the communication assembly B 1 , B 2 . Finally, the respective communication assembly B 1 , B 2 is activated by the control assembly SB as a result of the assignment of the respective network address of the communication assembly B 1 , B 2 . The procedure just outlined is also referred to as “loading” the assembly.
In the normal, error-free operating state of the communication network shown in FIG. 3 , initially only the communication assembly B 1 is loaded with operating software, configuration data and a network address. The communication assembly B 2 remains passive (inactive) at first. Since the terminal EG 3 stores the network address associated with the communication assembly B 1 , the terminal EG 3 can register with this communication assembly B 1 . When the terminal EG 3 registers and is set up, the communication assembly B 1 creates and alters configuration data, a copy of which is saved at regular intervals of time in a memory in the control assembly.
The control assembly SB monitors the communication assembly B 1 at regular intervals of time and, to this end, regularly requests a status report from this communication assembly B 1 . The communication assembly B 1 , in turn, regularly checks whether its connection to the data line LAN 3 and to the terminals registered with it, in this case the terminal EG 3 under consideration by way of example, exists. The information about whether the link to the data line LAN 3 or the connection to the registered terminals exists is transferred from the communication assembly B 1 to the control assembly SB upon the requests from the control assembly SB. If the control assembly SB is not able to receive a status report from the communication assembly B 1 , or a malfunction in the communication assembly B 1 or in its connection to the data network is revealed by one of the status reports received, then the control assembly SB identifies that there is an error in this communication assembly B 1 . If the control assembly now has another connection to the communication assembly B 1 , it switches the communication assembly B 1 to the operating state “inactive”. If there is no further connection to the communication assembly B 1 , then the control assembly assumes that the communication assembly B 1 is in an inactive operating state anyway. In both cases, the control assembly produces an internal status information item relating to the unobtainability or malfunction and now loads the communication assembly B 2 with operating software and with the configuration data which were originally saved as a copy by the communication assembly B 1 . Finally, the control assembly SB assigns the communication assembly B 2 that network address which was originally used by the communication assembly B 1 , and thus switches the communication assembly B 2 to the active operating state. The terminal EG 3 now uses the communication assembly B 2 without the need for it to have stored a different network address for the communication assembly which is to be used. In this case, no change to the possible scope of services has arisen.
In communication installations PBX having a relatively large number of active communication assemblies, only one inactive communication assembly needs to be reserved as a substitute assembly, because this substitute communication assembly is able to adopt the functionality of any of the active communication assemblies. In the present exemplary embodiment, all of the communication assemblies B 1 , B 2 are of the same type, which means that it is not necessary to convert the format of the configuration data which are stored as a copy and transferred to the communication assembly B 2 . If, by contrast, communication assemblies of different types are used, then an alignment program running on the control assembly SB converts the format of the configuration data before the communication assembly B 2 is loaded.
FIG. 4 shows, as a fourth exemplary embodiment, a distributed communication network with a central location Z and two subsidiary locations F 1 , F 2 , as is used, by way of example, for banks or insurance companies with a central office and a plurality of subsidiaries.
The subsidiary locations F 1 , F 2 operate the data networks LAN 4 , LAN 6 , and the central location Z operates the data network LAN 5 . In the subsidiary location F 1 , the data network LAN 4 has the terminal EG 4 , the communication node GK 7 , which is in the form of a gatekeeper, and the gateway GW 1 connected to it. The gateway GW 1 connects the subsidiary location F 1 to the public circuit switched communication network ISDN. Accordingly, the data network LAN 6 at the subsidiary location F 2 has the terminal EG 5 , the communication node GK 6 (likewise in the form of a gatekeeper) and the gateway GW 3 connected to it, the latter being connected to the communication network ISDN by means of the communication line Q 3 . Finally, the central location Z is equipped with the data network LAN 5 , the data network LAN 5 having the communication node GK 5 and the gateway GW 2 connected to it, with the gateway GW 2 being connected to the public communication network ISDN by means of the communication line Q 2 . The data networks LAN 4 and LAN 5 are connected to one another by means of the wide area data line WAN 1 , and the data network LAN 6 is connected to the data network LAN 5 by means of the wide area data line WAN 2 . The public communication network has at least one network node PS (“public switch”), to which the communication lines Q 1 , Q 2 , Q 3 and external subscriber lines (not shown here) can be linked.
The gateways GW 1 , GW 2 , GW 3 respectively represent the link from the respective data network LAN 4 , LAN 5 , LAN 6 to the public communication network ISDN. These gateways GW 1 , GW 2 , GW 3 are controlled by the respective communication node (gatekeeper) GK 7 , GK 5 , GK 6 in the respective data network LAN 4 , LAN 5 , LAN 6 . In the normal (fault free) operating situation in the communication network shown, all of the communication connections between the locations F 1 , F 2 , Z are handled using the wide area data line WAN 1 and WAN 2 . Connections to external subscribers, that is to say to subscribers who use the public communication network ISDN are routed exclusively via the communication line Q 2 and the gateway GW 2 .
The terminals EG 4 , EG 5 are registered with the communication node GK 5 , which also stores the configuration data associated with these terminals EG 4 , EG 5 . Hence, if the terminal EG 4 or the terminal EG 5 communicates with an external subscriber, this telephone connection is then routed, in the case of the terminal EG 4 , via the data network LAN 4 , then via the wide area data line WAN 1 , then via the data network LAN 5 and finally via the gateway GW 2 and the communication line Q 2 to the subscriber in the communication network ISDN. Similarly, calls between the terminal EG 5 and an external subscriber are routed using the data network LAN 6 , the wide area data line WAN 2 , via the data network LAN 5 , the gateway GW 2 , the communication line Q 2 and finally via the call processing facilities—not shown here—in the public communication network ISDN.
At the subsidiary location F 1 , the gateway GW 1 and the communication node GK 7 used to control the gateway GW 1 are thus used neither for external connections nor for the connections to the central location Z. Similarly, at the subsidiary location F 2 too, the network components gateway GW 3 and communication node GK 6 are not used during fault-free operation of the network. The configuration data associated with the terminals EG 4 , EG 5 are, as already mentioned, stored at the communication node GK 5 . A copy of the configuration data relating to the terminal EG 4 is stored at the communication node GK 7 . The communication node GK 7 is thus preprogrammed such that the terminal EG 4 can be operated at the communication node GK 7 instead of at the communication node GK 5 by way of substitution. If, as in the present exemplary embodiment, the communication node GK 7 as an emergency system has a lower power and is equipped with a smaller scope of services than the communication node GK 5 , then its configuration for the terminal EG 4 is naturally restricted. By way of example, the communication node GK 7 does not allow configuration of any call acceptance groups, which combine subscribers from the entire network comprising the locations F 1 , F 2 , Z.
To register with the communication node GK 5 and to use this communication node GK 5 , the terminal EG 4 stores the network address of the communication node GK 5 . As a second network address for the fault situation, the terminal EG 4 additionally stores the network address of the communication node GK 7 . A monitoring function installed in the terminal EG 4 checks at regular intervals of time whether the communication node GK 5 is obtainable. If this obtainability no longer exists, for example on account of failure of the wide area data line WAN 1 or on account of failure of the communication node GK 5 , the terminal EG 4 produces a corresponding status information item and registers with the communication node GK 7 . The communication node GK 7 is programmed such that all of the connections from the terminal EG 4 which, up until now, have been routed via the wide area data line WAN 1 and the communication node GK 5 , are now routed via the public communication network ISDN using the gateway GW 1 and the communication line Q 1 . Hence, despite the communication node GK 5 being unobtainable, the terminal EG 4 can continue to be used. Similarly, the terminal EG 5 is also programmed to use the communication node GK 6 and the gateway GW 3 instead of the wide area data line WAN 3 and the central communication node GK 5 by way of substitution.
The communication node GK 7 now used by way of substitution checks at regular intervals of time whether the communication node GK 5 is obtainable again. As soon as this is the case, the communication node GK 7 takes away the authorization to use it from the terminal EG 4 . As a result, the terminal EG 4 starts a fresh registration attempt, again in the order that first of all registration with the communication node GK 5 and only then a registration attempt with the communication node GK 7 are started. Since the communication node GK 5 is obtainable again however, the first registration attempt will be successful, which means that the original configuration of the communication network is restored.
Alternatively, the terminal EG 4 itself may also check at regular intervals of time whether the communication node GK 5 is obtainable again, and—if so—can sign off from the communication node GK 7 which is being used and can register with the communication node GK 5 again.
Incoming communication connections (calls) for the terminal EG 4 from a subscriber in the public communication network ISDN are routed from the public network node PS via the communication line Q 1 to the gateway GW 1 . The gateway GW “translates” the call, under the control of the communication node GK 7 as gatekeeper, into the data network LAN 4 . The call is routed via the wide area data line WAN 1 to the data network LAN 5 and hence into the “responsibility” of the communication node GK 5 . The terminal EG 4 is registered with the communication node GK 5 , which means that the call is now signaled on this terminal EG 4 , again via the data networks LAN 5 , LAN 4 and the wide area data line WAN 1 . In the error situation, that is to say when the wide area data line WAN 1 has failed, for example, not only does the terminal EG 4 register with the communication node GK 7 , but also the communication node GK 7 and hence the gateway GW 1 are changed over such that incoming communication connections are signaled to the terminal EG 4 directly from the communication node GK 7 .
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For alternate operation of a terminal (EG 1 ) at at least two communication nodes (GK 1 , GK 2 ), the terminal (EG 1 ) is first registered with a first of the communication nodes (GK 1 ). In this case, registration is followed by there being a logical connection between the terminal (EG 1 ) and the first communication node (GK 1 ). The obtainability of the first communication node (GK 1 ) is monitored, and in the event of the first communication node (GK 1 ) being unobtainable a status information item relating to the unobtainability is produced, and the status information item is taken as a basis for setting up a logical connection between the terminal (EG 1 ) and the second communication node (GK 2 ). The terminal (EG 1 ) is then automatically operated at the second communication node (GK 2 ).
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FIELD OF THE INVENTION
This invention pertains to loudspeaker enclosures. More particularly, it pertains to loudspeaker enclosures having enhanced freedom from resonance over a large range of frequencies generally in the bass frequency range.
BACKGROUND OF THE INVENTION
Review of the Prior Art
Loudspeaker enclosures designed for reproducing relatively low audio frequencies, i.e., in the range from about 100 hertz and below, have long been subject to objectionable resonances within the frequency ranges of their operation. For the purposes of this invention, a bass or low frequency loudspeaker or loudspeaker enclosure, is one intended to reproduce sound in the range of from about 250 hz and below down to the lower limit of the human hearing range which is in the neighborhood of 15-25 hz., depending upon the individual.
The problem encountered with a typical bass loudspeaker and its enclosure is that the combination tends to resonate at one or more points in the frequency range in which it is operated. These resonances result in boominess of the speaker, which boominess is sometimes preferred but which, nevertheless, is not consistent with faithful reproduction of the sound intended. For example, a typical bass loudspeaker enclosure is used to reproduce music in combination with mid-range and high frequency loudspeakers and enclosures therefor, in either a home or commercial audio system. In such a system the sound is recorded either on a phonograph record or on magnetic tape. The lower frequency sounds, as heard by a user of the system, are accentuated at some frequencies as compared to the relative volume of the sounds for those frequencies as recorded on the record or tape.
Great care is taken in the modern recording industry to cause the sound recorded on a phonograph record or tape to correspond, in frequency and volume, as faithfully as possible to the sound of the performance reproduced in the recording. Similarly, modern electronic audio equipment (amplifiers and the like) are extremely linear over their operating ranges and faithfully amplify and present to the loudspeakers electrical signals which similarly faithfully correspond to the sound generated in the performance embodied in the phongraph or tape recording. The presence of resonances in the loudspeaker system used to transduce the electrical output of the audio amplifier to an audible signal is at odds with and subverts the care taken in the original recording and in the reproduction amplifiers. These resonances are due in part to resonance effects in loudspeakers, but more importantly, as I have discovered, to resonances within the loudspeaker enclosures themselves. I have found that low frequency loudspeakers are very similar to each other in overall performance characteristics in respect to resonances, and that the more expensive low frequency loudspeakers now commercially available show only a small improvement in resonance characteristics as compared to the lower priced low frequency speakers commercially available.
That is, in the combination of a low frequency loudspeaker and an enclosure therefor, I have identified the enclosure, rather than the loudspeaker, as the principal source of resonances in the range of audible sound which the loudspeaker is used to reproduce in an overall audio reproduction system. A need therefore exists for an improved loudspeaker enclosure which, when used in combination with a low frequency loudspeaker, reproduces sound over the intended frequency range without objectionable resonances at one or more frequencies within such range.
SUMMARY OF THE INVENTION
This invention provides an improved loudspeaker enclosure which is particularly useful in the reproduction of sound in the bass or low frequency range. I have found that the present loudspeaker enclosure configuration is also useful to provide improved reproduction of so-called mid-range audio frequencies, but in these frequencies the improvements provided by this invention over the prior loudspeaker enclosures with which I am familiar are not as pronounced as in the case where the loudspeaker enclosure is arranged for use with a bass or low frequency loudspeaker.
This invention provides a loudspeaker enclosure which is remarkably free from resonances over the audio frequency range within which it is principally used regardless, as a general rule, of the quality or cost of the loudspeaker mounted in or to the enclosure. That is, the present loudspeaker enclosure enables a relatively low cost loudspeaker to be used to reproduce more realistic sound than is obtainable with a higher priced speaker used in the better of the loudspeaker enclosures now commercially available. The present loudspeaker enclosure is structurally simple, which means that it can be manufactured at reasonable cost. So far as I can ascertain, the present enclosure is not dependent upon critical geometrical relationships although there are certain geometrical relationships, which I have discovered to be important. The present loudspeaker enclosure is usable with a wide range of loudspeaker sizes; the important relationships which I have discovered enable the dimensions of the enclosure to be adjusted to correspond to the size of a particular loudspeaker, without significant variation in the performance of the enclosure from size to size.
Generally speaking, this invention provides a loudspeaker enclosure which includes a housing defining therein a principal volume having a front wall. The housing also defines the substantially smaller minor volume. The minor volume has a rear wall which is common to the front wall of the principal volume. The common wall between the minor and principal volumes defines a port which communicates the two volumes within the enclosure. A speaker mounting opening is defined in a front wall of the minor volume; this opening defines the only opening from the exterior of the housing to the interior.
DESCRIPTION OF THE DRAWINGS
The above-mentioned and other features of this invention are more fully set forth in the following detailed description of presently preferred embodiments of the invention, which description is presented with reference to the accompanying drawing, wherein:
FIG. 1 is a perspective view of a loudspeaker enclosure according to this invention; and
FIG. 2 is a cross-sectional elevation view of the enclosure.
DETAILED DESCRIPTION
A loudspeaker enclosure 10 according to this invention is shown in FIGS. 1 and 2. The enclosure is comprised of a housing 11 which has a major part 12 and a minor part 13. The housing major part 12 defines a principal volume 14 within the enclosure, whereas the housing minor part 13 defines a minor chamber 15 in the enclosure. The housing major part has a front wall 16 on which the housing minor part is constructed and mounted. Enclosure principal chamber 14 is completely sealed from the exterior of the enclosure, save for the presence in front wall 16 of an opening 17 which communicates to the enclosure minor volume. The enclosure minor volume, in turn, is completely sealed, save for the presence of opening 17 in its rear wall which is common to the housing principal part, and save for the presence in a front wall 18 thereof of a speaker mounting opening 19.
In use of the enclosure, a loudspeaker 20 is mounted in an airtight manner to the front wall of the housing minor part, preferably in a front mounting mode in which the rear surface of a speaker mounting flange 21 is engaged with the exterior surface of wall 18. The engagement of the loudspeaker to wall 18 is made in an airtight manner by a gasket which typically is provided on a rear face of the mounting flange 21. I prefer to use a front mounting mode of speaker 20 to enclosure 10, as currently recommended by loudspeaker manufacturers. I have found, however, that a rear mounting of the loudspeaker to the enclosure is also acceptable. A rear mounting mode is one in which the front face of flange 21 is engaged with the rear face or surface of enclosure wall 18.
Housing major part 12 has a width A (see FIG. 1), a depth B, and a height C. The housing minor part has a width D, a depth E, and a height F. Opening 17 has a dimension G, and the speaker mounting opening in wall 18 has a diameter H. The thickness of the material from which the enclosure is constructed is indicated in FIG. 2 by dimension I. Actual values for all of these dimensions for various sizes of loudspeaker enclosures, all constructed according to this invention, are set forth in Table I in which the dimensions and various relationships thereof are aligned in columns for different loudspeakers nominally sized at 8, 10, 12 and 15 inches, according to current practice among loudspeaker manufacturers.
In all of the enclosures to which Table I pertains, the inner surfaces of the principal chamber 1 were covered with a one-inch thickness of fiberglass padding. In all cases, the opening 17 between the principal and minor volumes of the enclosure was centered in the front wall of the principal enclosure, and the minor volume of the enclosure was centered relative to opening 17. In all cases, speaker mounting opening 19 was centered in wall 18. In each of the enclosures to which Table I pertains, the principal and minor volumes of the enclosures were of generally rectilinear or cubical configuration. All of these enclosures were constructed of particle board assembled by gluing and by wood screws.
In all of the enclosures described in Table I, opening 17 was square and had the same area as the internal vertical area of minor chamber 15; this is my present preference. However, opening 17 can have a smaller area than chamber 15 or can be circular in shaped, if desired.
TABLE I__________________________________________________________________________Table Enclosure LOUDSPEAKER SIZE (Nominal)Item Parameter 8 in. 10 in. 12 in. 15 in.__________________________________________________________________________1 A 16.0 in. 20.0 in. 22.0 in. 29.0 in.2 B 12.0 in. 12.0 in. 18.0 in. 17.0 in.3 C 16.0 in. 20.0 in. 22.0 in. 29.0 in.4 D 10.5 in. 13.0 in. 14.5 in. 19.25 in.5 E 6.75 in. 6.75 in. 6.75 in. 10.0 in.6 F 10.5 in. 13.0 in. 14.5 in. 19.25 in.7 G 9.0 in. sq. 11.5 in. sq. 13.0 in. sq. 17.0 in. sq.8 H 7.125 in. 9.0 in. 11.0 in. 14.0 in.9 I 3/4 in. 3/4 in. 3/4 in. 1-3/16 in.10 H/G 0.792 0.783 0.846 0.82611 G/C 0.563 0.575 0.591 0.58612 (D.E.F/A.B.C) 0.218 0.216 0.146 0.235 Internal13 (G Area/A.C) 0.249 0.260 0.274 0.270__________________________________________________________________________
In another enclosure according to this invention, similar to but not one of those enclosures listed in Table I, a twelve-inch loudspeaker was front-mounted to the front wall of a minor chamber having external dimensions of 13.5 inches high × 13.5 inches wide × 6 inches deep. Opening 17 in this enclosure was 12 inches square so as to make chamber 15 fully open to chamber 14. The principal chamber of the enclosure had overall dimensions of 22 inches high × 22 inches wide × 17 inches deep. The rear wall of the principal chamber was covered by a layer of fiberglass acoustical packing to a depth sufficient to leave a space of from 5 to 6 inches behind the front wall 16 of the principal chamber, as shown in FIG. 2 by packing material 22, the forward face of the packing material was covered by an impermeable membrane 23.
The data set forth in Table I (see Item No. 12) indicates that the relative volumes of the principal and minor chambers of the enclosure may vary rather substantially in relative size.
The reasons why loudspeaker enclosures, constructed as described above, have such significantly improved freedom from resonance is not understood. The absence of the resonances in the enclosures described above in the range of from 10 to 100 hz is believed to be particularly significant. It is in this range that the prior bass loudspeaker enclosures known to me exhibit significant objectionable resonance.
The loudspeaker network with which an enclosure of this invention is used can be adjusted to have the bass speaker rolloff frequencies at any frequency desired. My preference with the nominal 12 inch loudspeaker enclosure described above is to provide roll-off below about 25 to 30 hz and above about 60 to 80 hz.
The foregoing description has been made with reference to certain specific enclosure structures which are the enclosure arrangements which I presently prefer. Persons skilled in the art to which this invention pertains will understand that the principles of my development can be adapted in enclosures of different specific arrangement. Therefore, the foregoing description is principally illustrative and should not be regarded as restricting this invention in scope only to the particular enclosures which have been described.
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A loudspeaker enclosure comprises a housing defining therein a principal volume having a front wall and a substantially smaller minor volume. The minor volume has a rear wall common to the front wall of the principal volume. The common wall defines a port which communicates the minor volume to the principal volume. A speaker mounting opening is defined in a front wall of the minor volume. The speaker mounting opening defines the only opening from the exterior of the housing to the interior thereof.
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FIELD OF THE INVENTION
[0001] The field of the invention is subterranean tools that can drop multiple objects in a desired sequence from a location near the intended object landing location or locations.
BACKGROUND OF THE INVENTION
[0002] Devices that drop balls and darts are used in a variety of applications. For example in cementing the darts are used to wipe a liner clear of cement while dropped balls on seats can be used for allowing building pressure to set tools such as liner hangers/seals that are frequently used in conjunction with equipment for running or setting a liner in existing casing. These devices can be surface mounted on cementing heads for manual or automatic operation by rig personnel or they can be located remotely from a surface location and remotely operated from the surface by fluid flow patterns or remotely actuated detents that can release a potential energy force to launch a ball.
[0003] U.S. Pat. No. 4,452,322 shows in FIG. 2 a split view of a ball retained by a sliding sleeve with a flow passage through it. Fluid flow patterns with a j-slot overcome a resisting spring force and ultimately shifts the sleeve to align a port in the sleeve with a ball for gravity release of the ball. U.S. Pat. No. 7,100,700 uses high flow rates to create axial movement to release a ball at a subterranean location that is stored out of the fluid stream until released. Various surface mounted manually operated ball droppers are illustrated in U.S. Pat. No. 6,776,228 where a fork-shaped device straddles a ball and with rotation turns the ball into the flowpath. In U.S. Pat. No. 7,802,620 a handle is turned 180 degrees to cam a ball through an outlet as shown in FIG. 2 . Finally, U.S. Pat. No. 4,577,614 shows in FIG. 2 a remotely released detent that allows the potential energy of a spring to push balls out over the bias of a retaining leaf spring.
[0004] U.S. Pat. No. 7,299,880 shows a bypass that stays open to allow running of casing without surging the well where the bypass can be closed in the event of a well pressure event.
[0005] Some completion assemblies require torque transmitting capabilities and in some applications the ability to drop a ball on a seat if an earlier dropped dart fails to seat so a tool can be set. The present invention combines some of these capabilities by allowing release of a wiper plug with a pickup force. The pickup force allows the plug retainers to pivot to release a dart and at the same time at least obstruct a flow bypass that allowed flow around the dart before it was released. During running in and until the dart is released the tool components are rotationally locked at a first location and the lock at the first location releases when the plug is launched with an axial pick up force. Further picking up aligns a trapped ball in an axial slot in a mandrel with a mandrel exit hole where relative rotation then can cam the ball toward the exit hole and into the mandrel bore. The released ball can be a backup to set the same tool the dart was intended to set or it can set another tool altogether. The further axial movement to release the ball also engages an upper rotational lock to allow torque transmission for operation of other tools.
[0006] Those skilled in the art will more readily appreciate additional aspects of the present invention from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.
SUMMARY OF THE INVENTION
[0007] A subterranean tool can drop multiple objects to landing locations in a tubular string. The tool can keep at least one ball out of the fluid stream until ready for release. A dart or wiper plug can be kept in the fluid stream with an open bypass until axial mandrel movement allows release of the plug or dart. The tool is rotationally locked at a lower location for run in and then can rotationally lock at an upper location upon release of the dart or ball. Axial movement that releases the dart can continue until the ball aligns with a decreasing depth groove so that relative part rotation cams the ball against a leaf spring detent and into the mandrel flow path.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a section view of the tool during running in;
[0009] FIG. 2 is the view of FIG. 1 with an initial pickup force and before the dart is released;
[0010] FIG. 3 is the view of FIG. 2 with the dart released from further picking up;
[0011] FIG. 4 is the view of FIG. 3 with the ball aligned with an exit port in the mandrel so rotation can cam the ball into the mandrel using a decreasing radius surface;
[0012] FIG. 5 is an enlarged view of a portion of FIG. 1 ;
[0013] FIG. 6 is a perspective run in view at a lower end of the mandrel showing rotational locking between the mandrel and a surrounding sleeve;
[0014] FIG. 7 is the view of FIG. 6 after a pickup force that releases the dart showing the release of the lower rotational locking;
[0015] FIG. 8 is a perspective view near the top of the mandrel showing the upper rotational locking feature disengaged;
[0016] FIG. 9 is the view of FIG. 8 after picking up to release the dart showing the upper rotational lock engaged;
[0017] FIG. 10 is a perspective see through run in view showing the ball retained in the groove that has a decreasing radius and in an offset position from the exit port;
[0018] FIG. 11 is the view of FIG. 10 showing alignment of the ball with the mandrel exit port so that relative rotation cams the ball through the exit port overcoming a spring detent;
[0019] FIG. 12 is the view of FIG. 11 with the ball in the deepest part of the groove before relative rotation has started;
[0020] FIG. 13 is the view of FIG. 12 showing how rotation has cammed the ball past the detent so the ball can exit into the mandrel bore.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] Referring to FIG. 1 the relevant portions of the tool are illustrated. In the preferred embodiment a liner that is not shown is being cemented and the dart or wiper plug 10 is supported in the flow path 12 of the mandrel 14 by pivoting retainers 16 and 18 . Looking at FIG. 5 for an enlarged view, it can be seen that in the run in position of FIGS, 1 and 5 the pivoting retainers 16 and 18 have an end 20 that abuts surface 22 of the middle sleeve assembly 24 such that rotation about the pivot pin 26 cannot happen. Middle sleeve assembly 24 has an upper member 28 that is connected to lower member 30 at thread 32 . Mandrel 14 is pinned to upper member 28 at pin or pins 32 for run in. There is a flow bypass around the plug 10 with an entrance at 34 and an exit at 36 in an annular path 38 between the mandrel 14 and the middle sleeve assembly 24 . Upon raising the mandrel 14 the recesses 40 and 42 align with the ends 20 so that the retainers 16 and 18 can both pivot to release the plug 10 . The reason for the two retainers 16 and 18 is to hold the plug 10 in position against flow that can come in opposed directions. When the retainer 16 pivots to the release position that is shown in FIG. 3 it obstructs the exit 36 sufficiently to let applied pressure and the weight of the plug 10 to start the plug 10 moving downhole until it clears the exit 36 so that the plug can then be pumped the rest of the way to its intended destination downhole.
[0022] Also in the run in position there is a ball 44 that is located in a circumferential groove 46 as better seen in FIG. 10 . The bottom surface 48 of the groove 46 that is located in lower member 30 has a decreasing radius. The ball 44 is initially at an end of an axial slot 50 that terminates in an exit opening 52 that is sized bigger than the diameter of the ball 44 . The slot 50 allows the mandrel 14 to be lifted while the ball 44 is retained substantially within the wall of lower member 30 . At the end of the axial movement of the mandrel 14 the ball 44 is in registry with the opening 52 but still retained out of the mandrel passage 12 by a schematically illustrated detent 54 that is best see in FIG. 12 where the ball 44 is shown in the largest diameter of groove 46 . It can be seen that relative rotation of the mandrel 14 with respect to the lower member 30 will advance ball 44 along the decreasing radius of bottom surface 48 . Since the ball 44 at the time the relative rotation starts is axially aligned with opening 52 the result of the relative rotation will be to cam the ball 44 through the detent 54 allowing the ball to release into passage 12 to its ultimate destination further downhole. The detent 54 is schematically illustrated in FIG. 13 as having been pushed out of the way so that the ball 44 is free to fall into the passage 12 where it can travel by gravity or by being pumped to its end destination on a ball seat (not shown) that can then be used to pressure up to operate the same tool as the plug 10 was supposed to operate as a backup feature or some completely distinct tool can be operated with a landed ball 44 .
[0023] Referring back to FIGS. 1-4 the general sequence of operation is that the outer sleeve 56 is fixed in the wellbore such as with an attached packer that is not shown. The mandrel 14 is raised axially until the retainers 16 and 18 mounted to respective pivot pins 26 rotate when the recesses 40 and 42 have been raised to align with the ends 20 . Before this happens the shear pin or pins 34 break so that the mandrel 14 is no longer restrained to move axially in tandem with the sleeve assembly 24 . The shear pin or pins 34 break in the FIG. 3 position when the top end 57 of member 28 hits the drag block housing 58 that is supported by outer sleeve 56 which is in turn otherwise fixed in the wellbore with a packer or anchor that is not shown and the mandrel 14 is further pulled up with additional force. That same FIG. 3 position now has the ball 44 aligned with port 52 so that a subsequent rotation of the mandrel 14 while the sleeve assembly 24 is held against rotation by the meshing of teeth 60 and 62 ejects the ball 44 into the passage 12 . This is best seen when comparing FIGS. 8 for the run in position and FIG. 9 for the meshed position of teeth 60 and 62 so that the sleeve assembly 24 is held fixed as the rotation of mandrel 14 ejects the ball 44 to the passage 12 . The splines 66 and 68 release as upward movement of the mandrel 14 moves the travel stop 64 against the bottom of the sleeve assembly 24 and pushing the sleeve assembly 24 against teeth 62 to again rotationally lock the sleeve assembly against rotation so that mandrel 14 rotation will expel ball 44 . The meshed splines 66 and 68 insure that the ball 44 that rides on decreasing radius surface 48 will not jam the mandrel 14 to the sleeve assembly 24 until it is time to eject the ball 44 with rotation.
[0024] Referring to FIGS. 1 and 6 there is a travel stop assembly 64 on the mandrel 14 as well as a spline 66 that meshes with spline 68 that is internal to the sleeve assembly 24 . The splines 66 and 68 are engaged for run in to rotationally lock the mandrel 14 to the sleeve assembly 24 . As the mandrel 14 is picked up, the splines 66 move away from engagement from splines 68 and the teeth 60 and 62 ultimately mesh as the plug 10 is released and rotation then cams out the ball 44 into the mandrel passage 12 . Picking up the mandrel 14 will cause the sleeve assembly 24 to bottom on the travel stop 64 such that further raising of the mandrel 14 will bring teeth 60 and 62 together such that subsequent mandrel 14 rotation as the sleeve assembly 24 is held against rotation by the meshed teeth allows camming out of ball 44 .
[0025] Those skilled in the art will appreciate that the present invention allows bringing balls or plugs close to their ultimate destination before release. The plug that is in the mandrel flow path is bypassed for normal circulation flow and the plug is retained in position against flow in the mandrel passage in either one of two opposed directions. The mandrel is rotationally locked to the surrounding sleeve for run in with splines that separate as the mandrel is picked up. Picking up the mandrel allows the retainers for the plug to pivot out of the way with one of the retainers moving over one of the bypass ports to aid the plug in its initial movement beyond the bypass so that its own weight or pressure above can deliver the plug to the desired location.
[0026] While the mandrel and the surrounding sleeve assembly are initially pinned for tandem movement, picking up the mandrel releases the lower splines between the two and with a bottom travel stop on the mandrel brings the surrounding sleeve assembly to an upper travel limit where teeth mesh to retain the sleeve assembly against rotation while the mandrel can be turned to cam out a ball into the mandrel passage by pushing the ball past a bias and along a decreasing radius arc on a now stationary sleeve assembly and through a port that has come into alignment with the ball as a result of raising the mandrel.
[0027] While a single ball is shown as being released additional balls can also be used as well as multiple plugs by just adding additional facilities as those that are described for the ball and plug that are illustrated. While a cement application for a liner hanger is the preferred application, other completion or drilling applications are envisioned. While a plug and ball dropper are illustrated, they can be used separately depending on the application.
[0028] The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:
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A subterranean tool can drop multiple objects to landing locations in a tubular string. The tool can keep at least one ball out of the fluid stream until ready for release. A dart or wiper plug can be kept in the fluid stream with an open bypass until axial mandrel movement allows release of the plug or dart. The tool is rotationally locked at a lower location for run in and then can rotationally lock at an upper location upon release of the dart or ball. Axial movement that releases the dart can continue until the ball aligns with a decreasing depth groove so that relative part rotation cams the ball against a leaf spring detent and into the mandrel flow path.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application Nos. 2009-276930 filed on Dec. 4, 2009, 2009-276931 filed on Dec. 4, 2009, 2009-276932 filed on Dec. 4, 2009, 2009-276933 filed on Dec. 4, 2009, 2009-276934 filed on Dec. 4, 2009, and 2009-276935 filed on Dec. 4, 2009, the entire contents of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a method for preparing optically active amino acids or optically active amino acid amides. Particularly, the present invention relates to a method for efficiently preparing optically active tert-leucine or optically active tert-leucine amide.
BACKGROUND ART
[0003] Optically active amino acids or optically active amino acid amides are the compounds important as pharmaceutical raw materials or asymmetric ligands. As the method for preparing optically active amino acids or optically active amino acid amides has been described a method for preparing an optically active amino acid or an optically active amino acid amide as an enantiomer thereof by reacting a DL-amino acid amide with an enzyme which stereoselectively hydrolyzes a D- or L-isomer selective amino acid amide (e.g., Japanese Patent Laid-Open Publication No. 63-87998).
[0004] In order to appropriately proceed enzyme reactions, it is important to carry out the reactions at a pH and temperature range within the optimal condition of an enzyme to be used, and a method for adjusting an enzyme to the optimal condition is also known in the hydrolysis reaction of an amino acid amide by an enzyme which hydrolyzes the amino acid amide stereoselectively (for example, Japanese Patent Laid-Open Publication No. 2003-225094). However, even if the reaction is started under the optimal condition as described above, the reaction rate may be lowered along with the progress of the reaction resulting in insufficient completion of the aimed reaction in the case of the high concentration of the raw materials. In order to solve such matter and to conduct successfully the enzyme reaction at higher concentrations of the raw materials, a method for adding raw materials in the repeated partial fashion (for example, Japanese Patent Laid-Open Publication No. 2005-117905) and a method for sequentially extracting a product (for example, Japanese Patent Laid-Open Publication No. H11-137286) have been described. When the problems are not solved even by these methods, it will be necessary to increase the amount of an acid for adjusting pH or to increase an enzyme. However, when the acid for adjusting pH has been increased, it is necessary to increase the reaction steps in order to neutralize the acid added. Furthermore, a large amount of the salt is produced as a by-product to be discarded along with the neutralization. In addition, a large amount of bacterial cells to be discarded are produced in the production of the enzyme, so that these methods are not industrially desirable due to the defect that not only the amount of the bacterial cells to be discarded is increased in proportion to the increasing amount of the enzyme, but also the load on the separating operations of the bacterial cells and the salts after the enzyme reaction is increased.
[0005] In the hydrolysis reaction of amino acid amides, optically active amino acids and ammonia as a by-product are produced. In this connection, it has been described, for example, in Japanese Patent No. 4139773 and WO 2003/020929 that ammonium buffer solutions have been used as the buffer solution for the enzyme reaction of the enzyme. Furthermore, it has been described in Japanese Patent No. 3647065 that aqueous ammonia has been added for adjusting pH of an enzymatic reaction with an enzyme for hydrolyzing an amino acid amide. Thus, it may be predicated in the enzymatic reaction of an enzyme capable of hydrolyzing the amino acid amide that the negligible or no influence of ammonia or an ammonium ion is observed in the enzymatic reaction, since the use of an ammonia type buffer solution or the addition of ammonia for adjusting pH is generally conducted in this enzymatic reaction.
[0006] Japanese Patent Laid-Open Publication No. 2006-180751 discloses a method for removing ammonia as a by-product during the hydrolysis reaction with an enzyme capable of an amino acid amide. However, this method comprises the operation carried out at a high temperature for improving the solubility of an amino acid produced by the hydrolysis reaction to prevent the crystallization of the amino acid and thus is not a technique for improving the productivity by removing ammonia. Moreover, while it has been described in Japanese Patent Laid-Open Publication No. 2006-180751 that ammonia is not desirable to a microbial catalyst having amide hydrolyzing activity from the viewpoint of the activity and the stability of the catalyst, no measure to counter ammonia has not been described. It can rather be said that the use of an ammonia type buffer solution or the addition of ammonia for adjusting pH is generally conducted in this enzymatic reaction for hydrolyzing the amino acid amides.
[0007] For example, Japanese Patent Laid-Open Publication No. 2006-340630 discloses that ammonia affects the activity of an enzyme capable of amino acid amides and provides a countermeasure for avoid the influence of ammonia by searching new enzymes, which requires a great deal of labor and time and does not always find a new enzyme which is hardly affected by ammonia. In addition, even if the enzyme can avoid the influence of ammonia on a particular substrate, it may be influenced by ammonia on the other substrates. Thus, the search of a new enzyme cannot be said an effective means.
[0008] There has been described a method for preparing an optically active amino acid by the hydrolysis reaction with an enzyme capable of stereoselectively hydrolyzing an amino acid amide, after which reaction ammonia or an ammonium salt is removed by the addition of a base or the stripping, for example, in Japanese Patent Laid-Open Publication No. 2007-254439. However, this method aims at removing the ammonium salt having a low solubility in an organic solvent and then ammonia after the hydrolysis reaction.
[0009] It has been described in Japanese Patent Laid-Open Publication No. 2004-521623 and Japanese Patent Laid-Open Publication No. 61-285996 that ammonia can be removed by the distillation or the addition of salts as the conventional methods for removing ammonia in the hydrolysis reaction with the other enzymes. However, there have been described no methods as the combination of the reaction with a microbial catalyst having the amide hydrolysis activity and these methods for removing ammonia.
SUMMARY OF THE INVENTION
[0010] The present inventors have examined the enzymatic reaction for stereoselectively hydrolyzing DL-tert-leucine amide, and as a result, raised a problem that when the concentration of the amino acid amide as the raw material was increased without the increase of the amounts of neither an acid for adjusting pH nor of an enzyme, the reaction was not completed due to the deactivation of the enzyme along with the progress of the reaction in spite of the pH of the enzyme in the optimal range to lead to the stagnation of the reaction. Furthermore, a problem was also raised even in the use of an immobilized biocatalyst such as an immobilized enzyme, that the activity of the immobilized biocatalyst was strikingly lowered to the almost inability to the repeated use of the immobilized biocatalyst. Thus, a method for adding a raw material in portions, a method for sequentially taking out an amino acid as a product and a method for using these methods integrally were further examined, but the problem remained unsolved.
[0011] Thus, the present inventors have earnestly studied the inhibitory factors of an enzyme capable of hydrolyzing stereoselectively DL-tert-leucine amide and extraordinarily found that the enzyme used in the present invention is inhibited by ammonia and an ammonium ion in the presence of DL-tert-leucine amide as a substrate, although the information that the enzyme is not inhibited by ammonia in the presence of the other substrate (DL-2-methylcysteine amide hydrochloride) has been obtained (Referential Example 3). Now, the present inventors have found that the lowering of the enzymatic activity can be substantially reduced by decreasing the sum of the concentrations of ammonia and an ammonium ion by continuously or intermittently separating ammonia from the reaction solution during the hydrolysis reaction with the enzyme and an immobilized biocatalyst, if used, can be used repeatedly, and have successfully found the solution to the problem of the decreased reaction rate along the decrease of the activity. In this connection, it has been also found that the evaporation under reduced pressure and the adsorption on a cation exchange resin or zeolite are effective for the separation of ammonia from the reaction solution. Thus, the productivity per reactor could have been improved by increasing the concentration of the amino acid amide as the raw material in the reaction solution. It has been found as a result thereof that the productivity may be improved substantially without increasing a waste salt or waste cells as the waste matters of the reaction and that an optically active tert-leucine or an optically active tert-leucine amide can be prepared in high quality and inexpensively. The present invention is based on the information described above.
[0012] Thus, the object of the present invention is to provide a method for preparing optically active tert-leucine or optically active tert-leucine amide, in which the concentration of DL-tert-leucine amide as a raw material in the reaction solution can be enhanced without the need of increasing the amount of the cells or a pH-adjusting acid by maintaining the activity per unit amount of the enzyme, the cells or the cell treatment product and per unit time period at a high level in the enzymatic reaction for hydrolyzing the DL-tert-leucine amide stereoselectively, and consequently the productivity of optically active tert-leucine or optically active tert-leucine amide can be improved to a great extent without increasing the generation of a waste salt or waste cells.
[0013] The present invention relates to a method for producing D- or L-tert-leucine or D- or L-tert-leucine amide by reacting DL-tert-leucine amide with a biocatalyst selected from the group consisting of an enzyme capable of hydrolyzing the DL-tert-leucine amide stereoselectively, cells of a microorganism having the enzyme, a material produced by the treatment of the cells, an immobilized enzyme produced by immobilizing the enzyme onto a carrier, immobilized cells produced by immobilizing the cells onto a carrier, and an immobilized cell treatment product obtained by immobilizing the cell treatment product onto a carrier to thereby hydrolyze the DL-tert-leucine amide, wherein the hydrolysis is carried out with separating ammonia produced by the hydrolysis from the hydrolysis reaction solution.
[0014] According to the preferred embodiment of the present invention, in the method of the present invention, ammonia is separated from the reaction solution by
[0015] placing the reaction solution under reduced pressure to evaporate the ammonia, or
[0016] adsorbing the ammonia in the reaction solution onto a cation exchange resin or zeolite.
[0017] According to one preferred embodiment of the present invention, in the method of the present invention, ammonia is separated from the reaction solution by placing the reaction solution under reduced pressure to evaporate the ammonia.
[0018] According to another preferred embodiment of the present invention, in the method of the present invention, ammonia is separated from the reaction solution by adsorbing the ammonia in the reaction solution onto a cation exchange resin.
[0019] According to the still another preferred embodiment of the present invention, in the method of the present invention, ammonia is separated from the reaction solution by adsorbing the ammonia in the reaction solution onto zeolite.
[0020] According to one preferred embodiment of the present invention, in the method of the present invention, the enzyme is the one derived from Xanthobacter flavus.
[0021] According to one preferred embodiment of the present invention, in the method of the present invention, the microorganism is the one derived from Xanthobacter flavus and having the gene of an enzyme capable of hydrolyzing the DL-tert-leucine amide stereoselectively introduced therein.
[0000] According to one more preferred embodiment of the present invention, in the method of the present invention, the microorganism is pMCA1/JM109 (FERM BP-10334).
[0022] According to another preferred embodiment of the present invention, in the method of the present invention, the sum of the concentrations of ammonia and an ammonium ion in the reaction solution is in the range of 7000 ppm or less.
[0023] Furthermore, according to another embodiment of the present invention, a method for preparing a D- or L-amino acid or a D- or L-amino acid amide by reacting a DL-amino acid amide with an enzyme capable of hydrolyzing the DL-amino acid amide stereoselectively or a microorganism containing the enzyme or a microorganism treatment product to hydrolyze the amide, characterized in that the hydrolysis is carried out with separating ammonia produced by the hydrolysis from the reaction solution.
[0024] According to the present invention, in the enzymatic reaction stereoselectively hydrolyzing the DL-tert-leucine amide, the raw material concentration can be increased without increasing a waste salt or waste cells, so that D- or L-tert-leucine or D- or L-tert-leucine amide, particularly L-tert-leucine or D-tert-leucine amide can be prepared, in which the load of concentration operation and the like in the later steps can be reduced and the productivity per reactor has been substantially improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 shows the result of Example A.
[0026] FIG. 2 shows the schematic diagram of an apparatus used in Examples A-3 and D-2.
[0027] FIG. 3 shows the result of Example B.
[0028] FIG. 4 shows the result of Example C.
[0029] FIG. 5 shows the result of Example D.
[0030] FIG. 6 shows the result of Example E.
[0031] FIG. 7 shows the result of Example F.
DETAILED DESCRIPTION OF THE INVENTION
[0032] The present invention is now described with reference to the embodiments. The scope of the present invention is not limited by the embodiments and examples.
[0033] In the present invention, the term “DL-tert-leucine amide” means the mixture or racemic isomer of D- or L-tert-leucine amide.
[0034] In the present invention, a biocatalyst selected from the group consisting of an enzyme having an activity of stereoselectively hydrolyzing L- or D-tert-leucine amide corresponding to L- or D-tert-leucine, cells of a microorganism having the enzyme, a material produced by the treatment of the cells, an immobilized enzyme produced by immobilizing the enzyme onto a carrier, immobilized cells produced by immobilizing the cells onto a carrier, and an immobilized cell treatment product obtained by immobilizing the cell treatment product onto a carrier is used in the stereoselective hydrolysis of DL-tert-leucine amide.
[0035] Microorganisms having an enzyme capable of hydrolyzing stereoselectively DL-tert-leucine amide include, for example, those belonging to Xanthobacter, Protaminobacter, Mycobacterium , and Mycoplana genera. Specifically, there are mentioned Xanthobacter flavus, Protaminobacter alboflavus, Mycobacterium methanolica, Mycobacterium methanolica, Mycoplana ramosa, Mycoplana dimorpha, Variovorax paradoxus , and the like, but not limited thereto. More specific examples include Xanthobacter flavus NCIB 10071T, Protaminobacter alboflavus ATCC 8458, Mycobacterium methanolica BT-84 (FERM P8823), Mycobacterium methanolica P-23 (FERM P8825), Mycoplana ramosa NCIB 9440T, Mycoplana dimorpha ATCC 4279T, and Variovorax paradoxus DSM 14468.
[0036] Moreover, variants derived from these microorganisms by artificial mutational means or recombinant strains derived from these microorganisms by genetic methods such as cell fusion or genetic recombination including, for example, the strain pMCA1/JM109 (FERM BP-10334) having an enzyme capable of hydrolyzing stereoselectively an amino acid amide derived from Xanthobacter flavus by introducing the gene of the enzyme may also be used in the present invention. In addition, the cell treatment product includes, for example, a concentrated cell solution, dry cells, cell debris, a cell extract or a purified enzyme. Furthermore, an enzyme obtained by a method using no microorganisms such as a cell-free protein synthesis system may also be used.
[0037] The immobilized biocatalyst that the enzyme or the cells or the cell treatment product of a microorganism having the enzyme have been immobilized on a carrier (i.e., immobilized enzyme, immobilized cells, and immobilized cell treatment product) can be prepared by the methods well known in the art such as crosslinking method, covalent binding method, physical adsorption method and entrapment method. The carriers used in the immobilization include the conventional ones which may be appropriately used depending on the immobilization methods, specifically the carriers for the immobilization with natural polymers such as alginic acid, collagen, gelatin, agar, K-carrageenan and the like, synthetic polymers polyacrylamide, photo-curable resin, urethane polymer and the like, and microcapsules.
[0038] DL-tert-leucine amide as the raw material and the substrate of the enzymatic reaction is represented by the following general formula (1), in which R represents a tert-butyl group:
[0000]
[0039] To the aqueous solution of the DL-tert-leucine amide described above were added the enzyme, the cells of a microorganism having the enzyme, the cell treatment product, the immobilized enzyme, the immobilized cells or the immobilized cell treatment product and the other ingredients, if necessary, to prepare a reaction solution, which is subjected to stereoselective hydrolysis simultaneously with the separation of ammonia produced to prepare the optically active tert-leucine represented by the following general formula (2) or the optically active tert-leucine amide as the enantiomer thereof and represented by the following general formula (3). In this connection, the group R in the general formulae (2) and (3) refers to the same group R in the general formula (1).
[0000]
[0000] The concentration of DL-tert-leucine amide as the substrate in the reaction solution before stereoselective hydrolysis is preferably in the range from 0.01% by weight to the saturated concentration of DL-tert-leucine amide, more preferably 10 to 30% by weight. By setting the concentration of DL-tert-leucine amide within the range described above, the productivity per volume of the reaction solution can be enhanced since the substrate concentration will not be decreased excessively and the deactivation of the enzyme due to the high substrate concentration can be avoided.
[0040] The pH range suitable for the stereoselective hydrolysis of the DL-amino acid amide varies depending on enzymes to be used and cannot be indiscriminately defined. However, when pMCA1/JM109 (FERM BP-10334) is used as the enzyme, the reaction proceeds suitably at pH 6 to 10. The aqueous solution of the DL-tert-leucine amide has a pH at around 10.5, and thus it is necessary to adjust the pH by adding an acid to the aqueous solution for conducting the stereoselective hydrolysis under the optimal pH condition.
[0041] The acid to be added for adjusting pH is not specifically limited and may be a mineral acid or an organic acid, among which hydrochloric acid and acetic acid are suitably used. The amount of the acid to be used may be determined so as the pH to be in the range described above. For instance, hydrochloric acid is used in an amount of 0.005 to 0.5 molar times, preferably 0.05 to 0.4 molar times to DL-tert-leucine amide, and acetic acid is used in an amount of 0.005 to 1 molar times, preferably 0.05 to 0.7 molar times to DL-tert-leucine amide.
[0042] Some enzymes may improve the rate of stereoselective hydrolysis by the addition of a metal ion, and in such cases a variety of metal ions such as Ca 2+ , Co 2+ , Cu 2+ , Fe 3+ , Mg 2+ , Mn 2+ , Ni 2+ , Zn 2+ and the like may be added to the reaction solution, for example, in an amount of 1 to 100 ppm.
[0043] In the stereoselective hydrolysis reaction of DL-tert-leucine amide with an enzyme capable of hydrolyzing stereoselectively an amino acid amide, ammonia is generated in equimolar amount to the L- or D-tert-leucine to be produced. This ammonia is separated continuously or intermittently during the hydrolysis reaction from the reaction solution. The enzyme to be used in the present invention is inhibited by ammonia in the case of using DL-tert-leucine amide as a substrate, but the lowering of the reaction rate can be suppressed by separating ammonia from reaction solution during the hydrolysis to prevent the deactivation of the enzyme due to the increase of ammonia and in its turn the concentration of the raw material can be increased.
[0044] The deactivation of the enzyme due to ammonia and an ammonium ion is not only caused by the sum of the concentrations of ammonia and ammonium ion, but depends on enzymes and temperatures. Therefore, the concentration of ammonia in the reaction solution cannot be defined unconditionally. When the stereoselective hydrolysis reaction of DL-tert-leucine amide is carried out with pMCA1/JM109 (FERM BP-10334) as the enzyme in an aqueous solution at 40° C., the condition of separating ammonia is set so as the sum of the concentrations of ammonia concentration and an ammonium ion in the reaction solution to be in the range of 7000 ppm or less, preferably 6000 ppm or less.
[0045] When the enzyme, the microorganism having the enzyme or the treatment product thereof is recovered by the method well known to a person skillful in the art such as ultrafiltration after the reaction, the condition of separating ammonia is set so as the sum of the concentrations of ammonia concentration and an ammonium ion in the reaction solution to be preferably in the range of 3500 ppm or less, more preferably 2500 ppm or less.
[0046] When the enzyme capable of hydrolyzing stereoselectively the amino acid amide or the cell treatment product containing the enzyme is used as an immobilized biocatalyst, the deactivation of the enzyme by ammonia and the ammonium ion varies depending on the factors such as enzymes, immobilization methods and temperatures. For instance, when stereoselective hydrolysis is conducted with the cell pMCA1/JM109 (FERM BP-10334) as the immobilized biocatalyst in order to reuse the immobilized biocatalyst, the condition of separating ammonia is set so as the sum of the concentrations of ammonia concentration and an ammonium ion in the reaction solution to be in the range of 3500 ppm or less, preferably 2500 ppm or less.
[0047] Ammonia may be separated from either place of a reactor in which hydrolysis reaction is conducted or an ammonia separating apparatus provided apart from the reactor.
[0048] As the method for separating ammonia from the reaction solution, the reduced pressure method in which the reaction solution is placed under reduced pressure, the method in which ammonia is adsorbed on a cation exchange resin or the method in which ammonia is adsorbed on zeolite can be used.
[0049] The other methods for separating ammonia from the reaction solution include the method for aerating the reaction solution and the method for heating the reaction solution. However, the method for ventilating the reaction solution may unfavorably lead to incomplete reaction due to low amount of ammonia separable from the reaction solution. Furthermore, the method for heating the reaction solution may also unfavorably lead to the deactivation of the enzyme at a temperature for separating a sufficient amount of ammonia.
Reduced Pressure Method
[0050] In order to separate ammonia from the reaction solution, the reaction solution can be placed under reduced pressure to evaporate the ammonia.
[0051] In the reaction by the reduced pressure method, when the cell pMCA1/JM109 (FERM BP-10334) is used as the enzyme and the temperature of the reaction solution is set at 40° C., the pressure during the hydrolysis reaction of the DL-tert-leucine amide is preferably controlled in the range of not less than 40 mmHg which is the boiling pressure of the reaction solution to not more than 90 mmHg which is 50 mmHg higher than the boiling pressure.
[0052] If the amount of the reaction solution is decreased by the evaporation of water along with the separation of ammonia, water may be added externally.
[0000] Adsorption Method by a Cation Exchange Resin In order to separate ammonia from the reaction solution, ammonia in the reaction solution can be adsorbed on a cation exchange resin.
[0053] When a cation exchange resin is used, the cation exchange resin to be added to the reaction solution may be either a strong acidic ion exchange resin or a weak acidic ion exchange resin capable of adsorbing ammonia. Moreover, the resin to be selected is not limited by its types, forms or the like, but it may be appropriately determined by taking account of its adsorption capacity, ion exchange capacity, strength, price and the like, and for example, resins such as DOWEX 50WX8 (Dow Chemical) DIAION SK110 (Mitsubishi Chemical) and AMBERITE IR120B (Rohm and Haas) may be preferably used.
[0054] The amount of the cation exchange resin to be added to the reaction solution varies depending on the ion exchange capacity and adsorption capacity of the resin, but it needs only to be an amount satisfactory for adsorbing ammonia produced in the hydrolysis reaction. If the amount of the cation exchange resin to be added to the reaction solution is less than that sufficient for adsorbing ammonia produced in the hydrolysis reaction, the coexisting effect of the cation exchange resin cannot be satisfactorily anticipated, and the aimed reaction may not be completed due to the lowering of the reaction rate with the progress of the reaction. Moreover, when the cation exchange resin to be added to the reaction solution is in an excessively large amount, the amino acid, the amino acid amide, the cells and the enzyme may be adsorbed on the cation exchange resin resulting in the decrease of recovery or the rate of reaction. Thus, the suitable cation exchange resin is preferably added to the reaction solution in such amount that the ion exchange capacity of the resin is 0.05 to 2 times the amount of ammonia to be produced.
[0055] The cation exchange resin to be used needs only to be of an active type, and the used cation exchange resin can be used again by the activation of the resin.
[0056] The method for adding the cation exchange resin to the reaction solution needs only to substantially contact the cation exchange resin with the reaction solution, and for example, any method such as a method for adding directly a cation exchange resin to a reaction solution in a stirring reaction vessel for use of the resin in a suspension form, a method for filling a filter cloth or membrane or a cage type vessel with a cation exchange resin to place the resin in a reaction vessel, and a method for flowing or circulating a reaction solution through a tower which is filled with a cation exchange resin can be used. The method for adding directly a cation exchange resin to a reaction solution in a stirring reaction vessel for use of the resin in a suspension form is a simple and convenient method, but the method for filling a filter cloth or membrane or a cage type vessel with a cation exchange resin to place the resin in a reaction vessel or the method for flowing or circulating a reaction solution through a tower which is filled with a cation exchange resin is rather preferably used in consideration of the damage of the resin due to stirring and the laborious recovery of the resin after reaction. It is also possible to use a cation exchange resin formed into membrane or fiber.
[0000] Adsorption Method with Zeolite
[0057] In order to separate ammonia from the reaction solution, ammonia can be adsorbed onto zeolite in the reaction solution.
[0058] When zeolite is used, zeolite to be added to the reaction solution needs only to have an ability of adsorbing ammonia during the hydrolysis reaction, and any type of zeolite can be used without limitation including, for example, Mordenite, Zeolite Y, Chabazite and the like, which may be used taking in comprehensive consideration of adsorption capacity, ion exchange capacity, surface area per unit weight, strength, price and the like.
[0059] Zeolite to be added to the reaction solution is preferably used in a compact form which has a high strength and is hard to powder rather than in a powder form. The powdered zeolite adsorbs also the enzyme in addition to ammonia thus inhibiting the reaction. The zeolite compact having a low strength tends to be partly powdered thus inhibiting the reaction. In order to avoid the adsorption of the enzyme onto the powdered zeolite and the inhibition of the reaction, the method for filling a filter cloth or membrane or a cage type vessel with the compact to place it in a reaction vessel or the method for flowing or circulating a reaction solution through a tower which is filled with the compact is preferably used.
[0060] The amount of the zeolite to be added to the reaction solution varies depending on the types, adsorption capacity, ion exchange capacity and surface area per unit weight of zeolite, but it needs only to be an amount satisfactory for adsorbing ammonia produced in the hydrolysis reaction. If the amount of the zeolite to be added to the reaction solution is less than that sufficient for adsorbing ammonia produced in the hydrolysis reaction, the coexisting effect of the zeolite in the reaction solution will not be satisfactorily exhibited, and the aimed reaction may not be completed due to the lowering of the reaction rate with the progress of the reaction. Moreover, when the zeolite to be added to the reaction solution is in an excessively large amount, the amino acid, the amino acid amide, the cells and the enzyme may be adsorbed on the zeolite resulting in the decrease of recovery or the rate of reaction. Thus, the suitable zeolite is preferably added to the reaction solution in such amount that the ion exchange capacity of the zeolite is 0.05 to 2 times the amount of ammonia to be produced.
[0061] The zeolite to be used needs only to be in a situation capable of adsorbing ammonia and includes the proton type, and the used zeolite can be used again by treating it so as to be capable of adsorbing ammonia.
[0062] The method for adding the zeolite to the reaction solution needs only to substantially contact the zeolite with the reaction solution, and for example, any method such as a method for adding directly the zeolite to a reaction solution in a stirring reaction vessel for use of the zeolite in a suspension form, a method for filling a filter cloth or membrane or a cage type vessel with the zeolite to place the zeolite in a reaction vessel, and a method for flowing or circulating a reaction solution through a tower which is filled with the zeolite can be used. While the method for adding directly the zeolite to a reaction solution in a stirring reaction vessel for use of the zeolite in a suspension form is a simple and convenient method, it has the problems of the powdering of the compact due to stirring, the recovery of the zeolite after reaction and the adsorption of the cells on the zeolite. Thus, the method for filling a filter cloth or membrane or a cage type vessel with the zeolite to place the zeolite in a reaction vessel can exhibit the most preferable effect.
[0063] After the enzymatic reaction, optically active tert-leucine or optically active tert-leucine amide can be obtained from the reaction solution by the method well known to a person skillful in the art. For instance, the cells, proteins and nucleic acids are removed by adsorbing these materials on active carbon from the reaction solution after the enzymatic reaction, and optically active tert-leucine can be crystallized by taking advantage of the difference of solubilities between the optically active tert-leucine and the optically active tert-leucine amide as the enantiomer thereof by adding, for example, 2-methyl-1-propanol to the reaction solution. Thus, the optically active tert-leucine can be obtained as the crystalline form by filtering the solution. Furthermore, the filtrate obtained can be concentrated to dryness to give the optically active tert-leucine amide.
EXAMPLES
[0064] The present invention is now described in detail by way of examples, but not limited thereby.
Experimental Method and Measurement
[0065] The progress of reaction and the optical purity were measured by high performance liquid chromatography (HPLC), and the sum of the ammonia concentration and the ammonium ion concentration was measured by capillary electrophoresis. Analytical conditions are described below.
[HPLC Analytical Condition 1]
[0066] Column: Lichrosorb RP-18 (4.6φ×250 mm)
[0000] Eluent: 50 mM aqueous solution of perchloric acid
Flow rate: 0.5 ml/min
Detection: RI
[HPLC Analytical Condition 2]
Column: Sumichiral OA-5000 (4.6φ×50 mm)
[0067] Eluent: 10 mM aqueous solution of copper sulfate
Flow rate: 0.5 ml/min
Detection: UV 254 nm
[HPLC Analytical Condition 3]
Column: LiChrosorb 100RP-18 (4.6φ×250 mm)
[0068] Column temperature: 40° C.
Eluent: 50 mM aqueous solution of perchloric acid
Flow rate: 0.5 ml/min
Detection: RI
[Analytical Condition of Ammonia]
[0069] Apparatus: Capillary electrophoresis system 3DCE (Agilent)
Capillary length: 40 cm
Referential Example 1
Preparation of Cells
[0070] The recombinant strain pMCA1/JM109 (FERM BP-10334) having the L-tert-leucine amide stereoselective hydrolysis enzyme to be used in the following Examples and Comparative Examples was cultured in Turbo medium (Athena Environmental Sciences, Inc.; purchased from Funakoshi Corp.) at 37° C. and centrifuged to give a cell concentrate solution (containing 6.7% by weight of dry cells).
[0071] In this connection, the recombinant strain pMCA1/JM109 of Escherichia coli has been deposited to International Patent Organism Depositary, National Institute of Advanced Industrial Science and Technology on May 21, 2004 (Heisei 16) (original deposit date) (Tsukuba Central 6, 1-1, Higashi, Tsukuba, Ibaraki 305-8566, Japan) with accession no. FERM BP-10334.
Referential Example 2
Preparation of Immobilized Biocatalyst
[0072] An immobilized biocatalyst was prepared in the following manner. 27.2 g of PEG-1000 dimethacrylate (Shi-Nakamura Chemicaol Co., Ltd), 0.9 g of N,N′-methylenebisacrylamide, 1.0 g of tetramethylethylenediamine, 0.03 g of ammonium peroxodisulfate, 52.2 g of the concentrated cell solution obtained in Referential Example 1, and 18.7 g of pure water were mixed homogeneously and solidified by leaving to stand at ambient temperature. After solidified, the solid product was cut into a size of ca. 3 mm and used as an immobilized biocatalyst in the following Examples.
Referential Example 3
Effect of Ammonia on the Other Substrate in the Presence of Recombinant pMCA1/JM109
[0073] To a 500 ml flask was added 16.3 g of DL-2-methylcysteine amide hydrochloride (0.096 mole), which was dissolved in 141.3 g of water. To the aqueous solution was added 3.2 g of 28% aqueous ammonia, and the mixture was stirred. In this time, ammonia concentration was 5500 ppm. In addition, 2.97 mg of manganese chloride tetrahydrate and then 0.09 g of the concentrated cell solution of the recombinant pMCA1/JM109 prepared in Referential Example 1 were added, and the mixture was stirred at 30° C. under nitrogen stream for stereoselective hydrolysis. The examination of the rate of reaction with the HPLC condition 3 revealed that at least 95% of L-2-methylcysteine amide was converted into L-2-methylcysteine after 24 hours of the reaction and the sum of the ammonia concentration and the ammonium ion concentration in the reaction was 10000 ppm.
Example A
Reduced Pressure/Enzymatic Reaction
Example A-1
Reduced Pressure (40 mmHg)/Enzymatic Reaction
[0074] To a 200 ml flask was added 20.0 g of DL-tert-leucine amide (0.15 mole), which was dissolved in 78.4 g of water. To the aqueous solution was added 1.86 g of acetic acid (0.031 mole), and the mixture was stirred. At this time, the pH of the mixture was 8.3. In addition, 6.88 mg of manganese chloride tetrahydrate and then 0.60 g of the concentrated cell solution of the recombinant strain pMCA1/JM109 were added for stereoselective hydrolysis with stirring at 40° C. under reduced pressure of 40 mmHg.
[0075] The time-dependent change of the rate of reaction measured with the HPLC analytical condition 1 is illustrated in FIG. 1 . The rate of reaction in FIG. 1 refers to the percentage of L-tert-leucine amide converted into L-tert-leucine in the raw material DL-tert-leucine amide. After 27 hours of reaction, at least 99.5% of L-tert-leucine amide was converted into L-tert-leucine. Moreover, the measurement after 27 hours of reaction with the HPLC analytical condition 2 revealed that L-tert-leucine had an optical purity of 100% ee. The sum of the ammonia concentration and the ammonium ion concentration reached 5000 ppm after 5 hours of reaction and was always maintained at this level or less by removing ammonia from the reaction system.
[0076] A filtrate from which the cells had been removed by filtering the reaction solution having active carbon and a filter aid added thereto was obtained. The mixture of the filtrate with 65 g of 2-methyl-1-propanol was subjected to azeotropic dehydration until the hydrated concentration reached 1% under kPa for solvent displacement operation. The azeotropic dehydration proceeded at a boiling point of 60° C., and the boiling point reached 76° C. at the completion of azeotropic dehydration. L-tert-leucine crystallized by solvent displacement was collected by suction filtration, washed with 30 g of 2-methyl-1-propanol warmed to 70° C. and further with 90 g of acetone at 25° C., and subjected to vacuum drying at ambient temperature to give 9.8 g of white powder. Analysis of the L-tert-leucine according to the HPLC condition 1 revealed that the product had a chemical purity of 99.8%. The optical purity of the product measured according to the HPLC condition 2 was 99.5% or more.
Example A-2
Reduced Pressure (65 mmHg)/Enzymatic Reaction
[0077] The reaction was conducted in the same manner as that in Example A-1 except that the stereoselective hydrolysis was conducted at 65 mmHg. The result of the reaction is illustrated in FIG. 1 . After 68 hours of reaction, at least 99.5% of L-tert-leucine amide was converted into L-tert-leucine. Moreover, L-tert-leucine had an optical purity of 100% ee. The sum of the ammonia concentration and the ammonium ion concentration reached 6000 ppm after 7 hours of reaction and was always maintained at this level or less by removing ammonia from the reaction system.
Example A-3
Reduced Pressure (40 mmHg)/Enzymatic Reaction (Provided with an Ammonia Separating Apparatus)
1) Experimental Apparatus
[0078] Apparatus is schematically illustrated in FIG. 2 .
[0079] The reaction solution added to the reaction vessel 1 is reacted with stirring under atmospheric air while controlling the temperature of the reaction solution with the heater 2 . At the same time, a portion of the reaction solution is fed into the evaporator 4 as an ammonia separating apparatus through the transfer pump of the reaction solution 3 . The evaporator 4 is maintained under reduced pressure by the vacuum pump and also temperature controlled, and the reaction solution after separating ammonia is sent back to the reaction vessel 1 through the transfer pump of the reaction solution 5 . Moreover, water can be added to the reaction vessel 1 through the water supply line 6 .
2) Stereoselective Hydrolysis
[0080] To a 500 ml flask as a reaction vessel was added 50.39 g of DL-tert-leucine amide (0.38 mole), which was dissolved in 194.24 g of water. To the aqueous solution was added 4.62 g of acetic acid (0.031 mole), and the mixture was stirred. At this time, the pH of the mixture was 8.3. In addition, 9.01 mg of manganese chloride tetrahydrate and then 1.82 g of the concentrated cell solution of the recombinant strain pMCA1/JM109 were added for stereoselective hydrolysis with stirring at 40° C. under reduced pressure of 40 mmHg. Just after the initiation of the reaction, a portion of the reaction solution was continuously circulated through the evaporator at mmHg for removing ammonia produced with the enzymatic reaction. Water evaporated from the evaporator was supplied from the water supply line. The result of the reaction is illustrated in FIG. 1 . After 39 hours of reaction, at least 99.5% of L-tert-leucine amide was converted into L-tert-leucine. The sum of the ammonia concentration and the ammonium ion concentration reached 3500 ppm after 6 hours of reaction and was always maintained at this level or less by removing ammonia from the reaction system.
Comparative Example A-1
[0081] The reaction was conducted in the same manner as that in Example A-1 except that the stereoselective hydrolysis was conducted at atmospheric pressure. The result of the reaction is illustrated in FIG. 1 . After 45 hours of reaction, 47.4% of L-tert-leucine amide was converted into L-tert-leucine and the rest remained as L-tert-leucine amide. The sum of the ammonia concentration and the ammonium ion concentration increased with the advance of the reaction until 45 hours of reaction up to the maximum of 7800 ppm. Thus, the enzymatic reaction was not completed under atmospheric pressure condition.
Comparative Example A-2
[0082] The reaction was conducted in the same manner as that in Example A-1 except that the stereoselective hydrolysis was conducted at atmospheric pressure and nitrogen was circulated at the rate of 100 ml/min from the bottom part of the reaction solution. The result of the reaction is illustrated in FIG. 1 . After 24 hours of reaction, 52.0% of L-tert-leucine amide was converted into L-tert-leucine and the rest remained as L-tert-leucine amide. The sum of the ammonia concentration and the ammonium ion concentration increased with the advance of the reaction until 24 hours of reaction up to the maximum of 7200 ppm. Thus, the enzymatic reaction was not completed under atmospheric pressure condition.
Comparative Example A-3
[0083] The reaction was conducted in the same manner as that in Example A-1 except that the stereoselective hydrolysis was conducted at atmospheric pressure and at a temperature of 55° C. The result of the reaction is illustrated in FIG. 1 . After 24 hours of reaction, 15.8% of L-tert-leucine amide was converted into L-tert-leucine and the rest remained as L-tert-leucine amide. The sum of the ammonia concentration and the ammonium ion concentration increased with the advance of the reaction until 24 hours of reaction up to the maximum of 2000 ppm. Thus, the enzymatic reaction with use of the combination of the enzyme and the substrate was not completed due to the deactivation of the activation at high temperature.
Example B
Absorption of Cation Exchange Resin/Enzymatic Reaction
Example B-1
[0084] To a 100 ml flask was added 12.13 g of DL-tert-leucine amide (0.093 mole), which was dissolved in 44.31 g of water. To the aqueous solution was added 3.3 g of acetic acid (0.056 mole), and the mixture was stirred. At this time, the pH of the mixture was 8.3. In addition, 5.97 mg of manganese chloride tetrahydrate was added to the mixture to prepare the stock solution of the reaction. A 10.0 g portion of the stock solution was placed in a test tube, and 0.12 g of the concentrated culture solution of the recombinant strainpMCA1/JM109 (containing 0.008 g by weight of dry cells) was inoculated for stereoselective hydrolysis with stirring at 40° C. The cation exchange resin DOWEX 50WX8 (Dow Chemical) in an amount of 2.5 g was suspended into the reaction solution.
[0085] The progress of the reaction was confirmed by the high performance liquid chromatography (HPLC) condition 1. The result of the reaction is illustrated in FIG. 3 . After 69 hours of reaction, 99.8% of L-tert-leucine amide was converted into L-tert-leucine. The sum of the ammonia concentration and the ammonium ion concentration reached 5500 ppm after 20 hours of reaction and was always maintained at this level or less by removing ammonia from the reaction system.
[0086] A filtrate from which the cells and the cation exchange resin had been removed by filtering the reaction solution having active carbon and a filter aid added thereto was obtained. The mixture of the filtrate with 35 g of 2-methyl-1-propanol was subjected to azeotropic dehydration until the hydrated concentration reached 1% under 20 kPa for solvent displacement operation. The azeotropic dehydration proceeded at a boiling point of 60° C., and the boiling point reached 76° C. at the completion of azeotropic dehydration. L-tert-leucine crystallized by solvent displacement was collected by suction filtration, washed with 25 g of 2-methyl-1-propanol warmed to 70° C. and further with 75 g of acetone at 25° C., and subjected to vacuum drying at ambient temperature to give 5.9 g of white powder. Analysis of the L-tert-leucine according to the HPLC condition 1 revealed that the product had a chemical purity of 99.5%. The optical purity of the product measured according to the HPLC condition 2 was 99.5% or more.
Example B-2
[0087] Under the same condition as in Example B-1, a bag of 2.5 g of the cation exchange resin DOWEX 50WX8 (Dow Chemical) packed in unwoven fabric was added to the reaction solution. The result of the enzymatic reaction is illustrated in FIG. 3 . After 45 hours of reaction, 99.8% of L-tert-leucine amide was converted into L-tert-leucine. The sum of the ammonia concentration and the ammonium ion concentration reached 6000 ppm after 20 hours of reaction and was always maintained at this level or less by removing ammonia from the reaction system.
Comparative Example B-1
[0088] Under the same condition as in Example B-1, the reaction was conducted in the absence of a cation exchange resin. The result of the reaction is illustrated in FIG. 3 . After 46 hours of reaction, 68.5% of L-tert-leucine amide was converted into L-tert-leucine, and the rest remained as L-tert-leucine amide. The sum of the ammonia concentration and ammonium ion concentration in the reaction solution was increased with the progress of the reaction until 46 hours and reached the maximum of 8000 ppm.
Comparative Example B-2
[0089] To a 200 ml flask was added 20.0 g of DL-tert-leucine amide (0.15 mole), which was dissolved in 78.4 g of water. To the aqueous solution was added 1.86 g of acetic acid (0.031 mole), and the mixture was stirred. At this time, the pH of the mixture was 8.3. In addition, 6.88 mg of manganese chloride tetrahydrate and then 0.60 g of the concentrated cell solution obtained in Referential Example 1 were added and the mixture was subjected to stereoselective hydrolysis with stirring at 40° C. in the absence of a cation exchange resin. The result of the reaction is illustrated in FIG. 3 . After 45 hours of reaction, 47.4% of L-tert-leucine amide was converted into L-tert-leucine and the rest remained as L-tert-leucine amide. The sum of the ammonia concentration and the ammonium ion concentration was increased with the progress of the reaction until 45 hours and reached the maximum of 7800 ppm.
Example C
Adsorption of Zeolite/Enzymatic Reaction
Example C-1
[0090] To a 100 ml flask was added 12.13 g of DL-tert-leucine amide (0.093 mole), which was dissolved in 44.31 g of water. To the aqueous solution was added 3.3 g of acetic acid (0.056 mole), and the mixture was stirred. At this time, the pH of the mixture was 8.3. In addition, 5.97 mg of manganese chloride tetrahydrate was added to the mixture to prepare the stock solution of the reaction. After a 10.0 g portion of the stock solution was placed in a test tube, 0.24 g of the concentrated cell solution obtained in Referential Example 1 was inoculated and the mixture was subjected to stereoselective hydrolysis with stirring at 40° C. A 2.4 g pack of the molded tablets of Zeolite SAPO-34 (prepared according to Example 6 described in Japanese Patent Laid-Open Publication No. 2004-043296) in unwoven fabric was placed in the test tube so as the fabric to be immersed into the reaction solution.
[0091] The progress of the reaction was confirmed by the high performance liquid chromatography (HPLC) condition 1. The result of the reaction is illustrated in FIG. 4 . The rate of reaction in FIG. 4 refers to the percentage of L-tert-leucine amide converted into L-tert-leucine in the raw material DL-tert-leucine amide. After 45 hours of reaction, 99.6% of L-tert-leucine amide was converted into L-tert-leucine. The sum of the ammonia concentration and the ammonium ion concentration reached 6000 ppm after 20 hours of reaction and was always maintained at this level or less by removing ammonia from the reaction system.
[0092] A filtrate from which the cells and the zeolite had been removed by filtering the reaction solution having active carbon and a filter aid added thereto was obtained. The mixture of the filtrate with 35 g of 2-methyl-1-propanol was subjected to azeotropic dehydration until the hydrated concentration reached 1% under 20 kPa for solvent displacement operation. The azeotropic dehydration proceeded at a boiling point of 60° C., and the boiling point reached 76° C. at the completion of azeotropic dehydration. L-tert-leucine crystallized by solvent displacement was collected by suction filtration, washed with 25 g of 2-methyl-1-propanol warmed to 70° C. and further with 75 g of acetone at 25° C., and subjected to vacuum drying at ambient temperature to give 5.9 g of white powder. Analysis of the L-tert-leucine according to the HPLC condition 1 revealed that the product had a chemical purity of 99.5%. The optical purity of the product measured according to the HPLC condition 2 was 99.5% or more.
Comparative Example C-1
[0093] Under the same condition as in Example C-1, the reaction was conducted in the absence of zeolite. The result of the reaction is illustrated in FIG. 4 . After 46 hours of reaction, 68.5% of L-tert-leucine amide was converted into L-tert-leucine, and the rest remained as L-tert-leucine amide. The sum of the ammonia concentration and ammonium ion concentration in the reaction solution was increased with the progress of the reaction until 46 hours and reached the maximum of 8000 ppm.
Comparative Example C-2
[0094] The reaction was conducted in the same manner as in Example 1 except that the suspension of the powdered zeolite SAPO-34 was added to the stereoselective enzymatic reaction solution. The result of the reaction is illustrated in FIG. 4 . After 46 hours of reaction, 3.6% of L-tert-leucine amide was converted into L-tert-leucine, and the rest remained as L-tert-leucine amide. The sum of the ammonia concentration and ammonium ion concentration in the reaction solution was increased with the progress of the reaction until 46 hours and reached the maximum of 400 ppm.
Comparative Example C-3
[0095] To a 200 ml flask was added 20.0 g of DL-tert-leucine amide (0.15 mole), which was dissolved in 78.4 g of water. To the aqueous solution was added 1.86 g of acetic acid (0.031 mole), and the mixture was stirred. At this time, the pH of the mixture was 8.3. In addition, 6.88 mg of manganese chloride tetrahydrate and then 0.60 g of the concentrated cell solution obtained in Referential Example 1 were added and the mixture was subjected to stereoselective hydrolysis with stirring at 40° C. in the absence of zeolite. The result of the reaction is illustrated in FIG. 4 . After 45 hours of reaction, 47.4% of L-tert-leucine amide was converted into L-tert-leucine and the rest remained as L-tert-leucine amide. The sum of the ammonia concentration and the ammonium ion concentration was increased with the progress of the reaction until 45 hours and reached the maximum of 7800 ppm.
Example D
Enzymatic Reaction with an Immobilized Biocatalyst Under Reduced Pressure
Example D-1
Enzymatic Reaction with an Immobilized Biocatalyst Under Reduced Pressure Reduced Pressure (40 mmHg)
[0096] To 600.2 g of DL-tert-leucine amide (4.61 mole) dissolved in 4642.8 g of water was added 55.4 g of acetic acid (0.92 mole), and the mixture was stirred. At this time, the pH of the mixture was 8.3. In addition, 0.32 g of manganese chloride tetrahydrate was added and the mixture was regarded as a substrate solution. To 200 g of the substrate solution in 500 ml flask was added 14.4 g of the immobilized biocatalyst prepared in Referential Example 2, and the mixture was subjected to stereoselective hydrolysis with stirring at 40° C. under the pressure of 40 mmHg.
[0097] The whole amount of the reaction solution was taken out after 24 hours of reaction, and the surface of the immobilized biocatalyst and the flask were washed with pure water. To the mixture was added again 200 g of the substrate solution, and stereoselective hydrolysis was repeated with stirring at 40° C. under the pressure of 40 mmHg.
[0098] The rate of reaction after 24 hours measured with the HPLC analytical condition 1 is illustrated in FIG. 5 . The rate of reaction in FIG. 5 refers to the percentage of L-tert-leucine amide converted into L-tert-leucine in the raw material DL-tert-leucine amide. As the result of 10 repeated reactions with the same immobilized biocatalyst, 99.0% or more of L-tert-leucine amide was converted into L-tert-leucine after 24 hours in all reactions. Moreover, the measurement after 24 hours of reaction with the HPLC analytical condition 2 revealed that L-tert-leucine had an optical purity of 100% ee in all reactions. The sum of the ammonia concentration and the ammonium ion concentration reached 2000 ppm after 6 hours of reaction and was always maintained at this level or less by removing ammonia from the reaction system.
Example D-2
Enzymatic Reaction (Provided with Ammonia Separating Apparatus) with Immobilized Biocatalyst Under Reduced Pressure (40 mmHg)
1) Experimental Apparatus
[0099] The apparatus is schematically illustrated in FIG. 2 . The reaction solution in the reaction solution reservoir 1 is temperature controlled with the heater 2 and exposed to the atmosphere. At the same time, a portion of the reaction solution is sent to the reactor and evaporator 4 as the ammonia separating apparatus having the immobilized biocatalyst filled therein through the transfer pump of the reaction solution 3 . The reactor and evaporator 4 is led to reduced pressure by the vacuum pump and temperature controlled. The reaction solution is subjected to reaction in the presence of the immobilized biocatalyst to remove ammonia, and returned to the reaction solution reservoir 1 through the transfer pump of the reaction solution 5 . Furthermore, water can be added to the reaction solution reservoir 1 through the water supply line 6 during the reaction.
2) Stereoselective Hydrolysis
[0100] To 600.5 g of DL-tert-leucine amide (4.61 mole) dissolved in 2357.7 g of water was added 56.2 g of acetic acid (0.94 mole), and the mixture was stirred. At this time, the pH of the mixture was 8.3. In addition, 0.32 g of manganese chloride tetrahydrate was added and the mixture was regarded as a substrate solution. In a 500 ml flask was filled 200 g of the substrate solution. 29.6 g of the immobilized biocatalyst prepared in Referential Example 2 was filled in the reactor and the evaporator, and the mixture was set at 40° C. under the pressure of 40 mmHg. A portion of the substrate solution was circulated at a flow rate of 30 ml/min for stereoselective hydrolysis and the removal of ammonia. The amount of water decreased by evaporation is supplied from the water supply line.
[0101] The whole amount of the reaction solution was taken out after 24 hours of reaction, and the surfaces of the flask and the immobilized biocatalyst were washed with pure water by circulating it through the flask and the reactor and evaporator. To the mixture was added again 200 g of the substrate solution, and stereoselective hydrolysis was repeated.
[0102] The rate of reaction after 24 hours measured with the HPLC analytical condition 1 is illustrated in FIG. 5 . As the result of 10 repeated reactions with the same immobilized biocatalyst, 99.0% or more of L-tert-leucine amide was converted into L-tert-leucine after 24 hours in all reactions.
[0103] Moreover, the measurement after 24 hours of reaction with the HPLC analytical condition 2 revealed that L-tert-leucine had an optical purity of 100% ee in all reactions. The sum of the ammonia concentration and the ammonium ion concentration reached 3000 ppm after 6 hours of reaction and was always maintained at this level or less by removing ammonia from the reaction system.
Comparative Example D-1
[0104] Stereoselective hydrolysis was conducted in the same manner as in Example D-1, except that the reaction was conducted under atmospheric pressure. The rate of reaction after 24 hours with the HPLC analytical condition 1 is illustrated in FIG. 5 . The rate of reaction in FIG. 5 refers to the percentage of L-tert-leucine amide converted into L-tert-leucine in the raw material DL-tert-leucine amide. In the first reaction, 96.9% of L-tert-leucine amide was converted into L-tert-leucine after 24 hours. On the other hand, the reaction rate remained less than 27% after 24 hours, and thus the immobilized biocatalyst could not be used again.
[0105] In this connection, the sum of the ammonia concentration and the ammonium ion concentration was increased with the progress of the reaction until 24 hours and reached the maximum of 7000 ppm.
Comparative Example D-2
[0106] In the same manner as in Example D-2, 9 stereoselective hydrolysis reactions were conducted repeatedly. In the seventh reaction, stereoselective hydrolysis was conducted under the atmospheric pressure of the reactor and evaporator 4 after 7.5 hours-22.5 hours. In the sequential 8th and 9th reactions, stereoselective reactions were conducted with the reactor and evaporator 4 set at the pressure of 40 mmHg in the same manner as in Example 2. While the sum of the ammonia concentration and ammonium ion concentration in the 1st-6th as well as 8th and 9th reaction solutions remained 3500 ppm at most, it reached 4500 ppm maximally at the seventh reaction. The rate of reaction after 24 hours with the HPLC analytical condition 1 is illustrated in FIG. 5 . In the 1st-7th reactions, 99.5% or more of L-tert-leucine amide was converted into L-tert-leucine after 24 hours. On the other hand, the reaction rate remained less than 89% after 24 hours on and after the 8th reaction, and thus the immobilized biocatalyst could not be used again.
Example E
Adsorption on Cation Exchange Resin/Enzymatic Reaction with Immobilized Biocatalyst
Example E-1
[0107] To 600.2 g of DL-tert-leucine amide (4.61 mole) dissolved in 4642.8 g of water was added 55.4 g of acetic acid (0.92 mole), and the mixture was stirred. At this time, the pH of the mixture was 8.3. In addition, 0.32 g of manganese chloride tetrahydrate was added and the mixture was regarded as a substrate solution. To 10.0 g of the substrate solution in a test tube was suspended 2.5 g of the cation exchange resin DOWEX 50WX8 (Dow Chemical), followed by 2.9 g of the immobilized biocatalyst prepared in Referential Example 2, and the mixture was subjected to stereoselective hydrolysis with stirring at 40° C.
[0108] The whole amount of the reaction solution was taken out after 24 hours of reaction, and the immobilized biocatalyst was separated. After the surface of the immobilized biocatalyst and the test tube were washed with pure water, 10.0 g of the substrate solution and 2.6 g of the cation exchange resin were added again to the mixture, and stereoselective hydrolysis was repeated with stirring at 40° C.
[0109] The rate of reaction after 24 hours measured with the HPLC analytical condition 1 is illustrated in FIG. 6 . The rate of reaction in FIG. 6 refers to the percentage of L-tert-leucine amide converted into L-tert-leucine in the raw material DL-tert-leucine amide. As the result of 5 repeated reactions with the same immobilized biocatalyst, 99.0% or more of L-tert-leucine amide was converted into L-tert-leucine after 24 hours in all reactions.
[0110] Moreover, the measurement after 24 hours of reaction with the HPLC analytical condition 2 revealed that L-tert-leucine had an optical purity of 100% ee in all reactions. The sum of the ammonia concentration and the ammonium ion concentration reached the maximum of 2000 ppm after 6 hours of reaction and was always maintained at this level or less by removing ammonia from the reaction system.
[0111] A filtrate from which the cells had been removed by filtering the reaction solution having active carbon and a filter aid added thereto was obtained. The mixture of the filtrate with 10 g of 2-methyl-1-propanol was subjected to azeotropic dehydration until the hydrated concentration reached 1% under kPa for solvent displacement operation. The azeotropic dehydration proceeded at a boiling point of 60° C., and the boiling point reached 76° C. at the completion of azeotropic dehydration. L-tert-leucine crystallized by solvent displacement was collected by suction filtration, washed with 5 g of 2-methyl-1-propanol warmed to 70° C. and further with 15 g of acetone at 25° C., and then subjected to vacuum drying at ambient temperature to give 0.96 g of white powder. Analysis of the L-tert-leucine according to the HPLC condition 1 revealed that the product had a chemical purity of 99.0%. The optical purity of the product measured according to the HPLC condition 2 was 99.5% or more.
Comparative Example E-1
[0112] Stereoselective hydrolysis was conducted in the same manner as that in Example E-1 except that no ion exchange resin was added. The rate of reaction after 24 hours of reaction with the HPLC analytical condition 1 is illustrated in FIG. 6 . In the 1st reaction, 96.9% of L-tert-leucine amide was converted into L-tert-leucine after 24 hours of reaction. On the other hand, the reaction rate remained less than 27% after 24 hours on and after the second reaction, and thus the immobilized biocatalyst could not be used again.
[0113] In this connection, the sum of the ammonia concentration and the ammonium ion concentration in the first reaction solution was increased with the progress of the reaction until 24 hours and reached the maximum of 7000 ppm.
Example F
Adsorption on Zeolite/Enzymatic Reaction with Immobilized Biocatalyst
Example F-1
[0114] To 600.2 g of DL-tert-leucine amide (4.61 mole) dissolved in 4642.8 g of water was added 55.4 g of acetic acid (0.92 mole), and the mixture was stirred. At this time, the pH of the mixture was 8.3. In addition, 0.32 g of manganese chloride tetrahydrate was added and the mixture was regarded as a substrate solution. A 10.0 g portion of the substrate solution was placed in a test tube. A 2.4 g pack of the molded tablets of Zeolite SAPO-34 (prepared according to Example 6 described in Japanese Patent Laid-Open Publication No. 2004-043296) in unwoven fabric was placed in the test tube so as the fabric to be immersed into the reaction solution. In addition, 2.9 g of the immobilized biocatalyst prepared in Referential Example 2 was added, and the mixture was subjected to stereoselective hydrolysis with stirring at 40° C. The whole amount of the reaction solution was taken out after 24 hours of reaction, and the immobilized biocatalyst was separated. After the surface of the immobilized biocatalyst and the test tube were washed with pure water, 2.4 g of the zeolite packed in the unwoven fabric was placed in the test tube so as the fabric to be immersed into the reaction solution. In addition, 10.0 g of the substrate solution was added again to the mixture, and stereoselective hydrolysis was repeated with stirring at 40° C.
[0115] The rate of reaction after 24 hours measured with the HPLC analytical condition 1 is illustrated in FIG. 7 . The rate of reaction in FIG. 7 refers to the percentage of L-tert-leucine amide converted into L-tert-leucine in the raw material DL-tert-leucine amide. As the result of 5 repeated reactions with the same immobilized biocatalyst, 99.0% or more of L-tert-leucine amide was converted into L-tert-leucine after 24 hours in all reactions.
[0116] Moreover, the measurement after 24 hours of reaction with the HPLC analytical condition 2 revealed that L-tert-leucine had an optical purity of 100% ee in all reactions. The sum of the ammonia concentration and the ammonium ion concentration reached the maximum of 2000 ppm after 6 hours of reaction and was always maintained at this level or less by removing ammonia from the reaction system.
[0117] A filtrate from which the cells and the zeolite had been removed by filtering the reaction solution having active carbon and a filter aid added thereto was obtained. The mixture of the filtrate with 35 g of 2-methyl-1-propanol was subjected to azeotropic dehydration until the hydrated concentration reached 1% under 20 kPa for solvent displacement operation. The azeotropic dehydration proceeded at a boiling point of 60° C., and the boiling point reached 76° C. at the completion of azeotropic dehydration. L-tert-leucine crystallized by solvent displacement was collected by suction filtration, washed with 25 g of 2-methyl-1-propanol warmed to 70° C. and further with 75 g of acetone at 25° C., and then subjected to vacuum drying at ambient temperature to give 5.9 g of white powder. Analysis of the L-tert-leucine according to the HPLC condition 1 revealed that the product had a chemical purity of 99.5%. The optical purity of the product measured according to the HPLC condition 2 was 99.5% or more.
Comparative Example F-1
[0118] Stereoselective hydrolysis was conducted in the same manner as that in Example F-1 except that no zeolite was added. The rate of reaction after 24 hours of reaction with the HPLC analytical condition 1 is illustrated in FIG. 7 . In the first reaction, 96.9% of L-tert-leucine amide was converted into L-tert-leucine after 24 hours of reaction. On the other hand, the reaction rate remained less than 27% after 24 hours on and after the second reaction, and thus the immobilized biocatalyst could not be used again.
[0119] In this connection, the sum of the ammonia concentration and the ammonium ion concentration in the first reaction solution was increased with the progress of the reaction until 24 hours and reached the maximum of 7000 ppm.
DESCRIPTION OF SYMBOLS IN THE DRAWINGS
[0000]
1 Reaction vessel or reaction solution reservoir
2 Heater
3 Transfer pump of reaction solution
4 Evaporator or reactor and evaporator
5 Transfer pump of reaction solution
6 Water supply line
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The present invention relates to a method for producing D- or L-tert-leucine or D- or L-tert-leucine amide by reacting DL-tert-leucine amide with a biocatalyst selected from the group consisting of an enzyme capable of hydrolyzing the DL-tert-leucine amide stereoselectively, cells of a microorganism having the enzyme, a material produced by the treatment of the cells, an immobilized enzyme produced by immobilizing the enzyme onto a carrier, immobilized cells produced by immobilizing the cells onto a carrier, and an immobilized cell treatment product obtained by immobilizing the cell treatment product onto a carrier to thereby hydrolyze the DL-tert-leucine amide, wherein the hydrolysis is carried out with separating ammonia produced by the hydrolysis from the hydrolysis reaction solution. According to the present invention, the concentration of an amino acid amide as a raw material in the reaction solution can be enhanced without the need of increasing the amount of the cells or a pH-adjusting acid by maintaining the activity per unit amount of the enzyme, the cells or the cell treatment product and per unit time period at a high level in the enzymatic reaction for hydrolyzing an amino acid amide stereoselectively, and consequently the productivity of optically active tert-leucine or optically active tert-leucine amide can be improved to a great extent without increasing the generation of a waste salt or waste cells.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of our application, application Ser. No. 09/255,300, filed Feb. 22, 1999, now U.S. Pat. No. 6,162,949, which in turn is a continuation-in-part of application Ser. No. 08/357,910 filed Dec. 16, 1994, now U.S. Pat. No. 5,889,186 all of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
At the molecular level biological systems are highly asymmetric; enzymes, proteins, polysaccharides, nucleic acids, and many other fundamental components of life are present in optically active form. The implications of this are profound; as a general proposition the interaction of a chiral molecule with an optically active site is a diastereomeric interaction, and the two enantiomers properly should be viewed as distinct compounds capable of acting in different ways. (R)-Asparagine has a bitter taste, whereas the (S)-isomer is sweet. It has been known for some time that for medicinals having at least one chiral center the pharmacological effectiveness of the enantiomers of the racemic mixture may differ substantially, and in some cases the pharmacological action itself may differ. An extreme example is provided by propranolol, where the major pharmacological effect of the (R)-isomer is as a contraceptive, whereas the major pharmacological effect of the (S)-isomer is as a beta-blocker.
Although the recognition of the desirability of using the pharmacologically and pharmaceutically more acceptable enantiomer is old, nonetheless the use of optically pure medicinals generally is relatively new, simply because of the difficulty and cost of resolution of the racemic mixture and/or the difficulty and cost of asymmetric synthesis of the desired enantiomer. The importance of stereochemical purity may be exemplified by (S)-propranolol, which is known to be 100 times more potent as a beta-blocker than its (R)-enantiomer. Furthermore, optical purity is important since certain isomers actually may be deleterious rather than simply inert. For example, the R-enantiomer of thalidomide was a safe and effective sedative when prescribed for the control of morning sickness during pregnancy. However, S-thalidomide was discovered to be a potent teratogen leaving in its wake a multitude of infants deformed at birth.
With recent chemical advances, especially in asymmetric synthesis, has come both an increase in the feasibility of selectively preparing the desired enantiomer of a given chiral medicinal, as well as increasing pressure on the pharmaceutical industry to make available only that enantiomer. Instructive examples, pertinent to the subject matter of this invention, are the antidepressant cis-(1S)(4S)-N-methyl-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-1-naphthalenamine, (hereinafter, “sertraline, or where racemic, “racemic sertraline”), which has Formula I, and the class of compounds (hereinafter, “sertraline analogs” or where racemic, “racemic sertraline analogs”) having Formula II.
Thus, there is described in U.S. Pat. Nos. 4,536,518, and 4,556,676 to W. M. Welch, Jr., as well as in the paper of W. M Welch, Jr. et. al., Journal of Medicinal Chemistry , Vol. 27, No. 11, p. 1508, (1984) a multi-step method for synthesizing pure cis-(1S)(4S)-N-methyl-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-1-naphthalenamine. An important synthetic step involves reduction of a precursor immine to the corresponding amine, which reduction results in a mixture of the cis and trans isomers in the form of a racemate. This isomeric mixture is then separated by chromatography on silica gel or by fractional crystallization of the hydrochloride salts. The cis racemate amine free base is then classically resolved with an optically-selective precipitant acid, as is known in the art, to yield sertraline.
The foregoing are examples of conventional synthesis and separation, as are known in the art, relevant to sertraline in which isomer separation of a sertraline precursor is performed by chromatography or by crystallization, and enantiomer separation leading to the final target medicinal sertraline is performed by optically-selective precipitation. Another approach of resolving a precursor is exemplified by the work of Schneider and Goergens, Tetrahedron: Asymmetry , No. 4, 525, 1992. These authors effected enzymatic resolution of 3-chloro-1-phenyl-1-propanol (CPP) via enzymatic hydrolysis of the racemic acetate in the presence of a lipase from Pseudomonas fluorescens under close pH control with a phosphate buffer. The hydrolysis was halted after about 50% conversion to afford the R-alcohol while leaving unchanged the S-acetate, which subsequently could be hydrolyzed with base to the S-alcohol. From the enantiomerically pure alcohols the enantiomerically pure serotonin-uptake inhibitors fluoxetine (whose racemate is available as Prozac™), tomoxetine, and nisoxetine could be prepared.
The Schneider and Goergens approach highlights a characteristic of methods based on resolution of a racemate, whether the racemate is that of a precursor or of a final medicinal compound, which requires our attention. The authors used both the R- and S-CPP to prepare both R- and S-fluoxetine in high optical purity, although one enantiomer is substantially more desirable than the other (see U.S. Pat. No. 5,104,899, supra). Consequently, in practice only, the more desirable enantiomer will be utilized, either in subsequent synthesis or as the final chiral medicinal. There then results the economic burden of discarding the less desirable (or even undesirable) enantiomer, whether of a precursor or of a final medicinal. Thus, it is imperative to somehow utilize the undesired enantiomer which results from resolution. Stated concisely, incident to a method of preparing medicinals of high optical purity based on resolution of a racemate of a raw material, intermediate or of a final medicinal, is the requirement of utilizing the unwanted enantiomer produced as a byproduct of the resolution stage. For a final medicinal compound, perhaps the most desirable utilization of the unwanted enantiomer would be to racemize it and recycle the racemate back to the separation stage; this application is directed precisely to such a process.
SUMMARY OF THE INVENTION
The purpose of the present invention is to present a process for the preparation of sertraline and for preparation of the more desirable enantiomers of sertraline analogs. One embodiment comprises separation of isomeric racemic sertraline or isomeric racemic sertraline analogs by simulated moving bed chromatography using a chiral or non-chiral adsorbent to afford at least one substantially pure racemic sertraline isomer or racemic sertraline analog isomer, resolution of a sertraline isomer racemate or sertraline analog isomer racemate by simulated moving bed chromatography using a chiral adsorbent to afford at least one substantially pure sertraline enantiomer pair or sertraline analog enantiomer pair, resolution of a sertraline enantiomer pair or sertraline analog enantiomer pair by simulated moving bed chromatography using a chiral adsorbent to afford substantially pure sertraline or at least one substantially pure sertraline analog, and conversion of less desirable isomers and/or enantiomers to a mixture of isomeric racemic sertraline or sertraline analogs, with recycle to the an appropriate resolution stage. In a specific embodiment cis-(1S)(4S)-N-methyl-4-(3,4-dichlorophenyl)-1,2,3,4-tetrahydro-1-naphthalenamine is utilized as the substantially pure sertraline enantiomer.
DESCRIPTION OF THE FIGURES
FIG. 1 represents a process flow for the preparation of sertraline or sertraline analogs utilizing simulated moving bed chromatography to resolve isomeric racemic sertraline or isomeric racemic sertraline analogs into sertraline or sertraline analogs, and recycle of the other isomers and enantiomers to the resolution stage.
FIG. 2 represents a process flow for the preparation of sertraline or sertraline analogs utilizing simulated moving bed chromatography to resolve isomeric sertraline or sertraline analogs into sertraline or sertraline analogs, and recycle of the other isomers to the resolution stage.
DESCRIPTION OF THE INVENTION
The present invention is better understood in the context of synthetic routes to sertraline and sertraline analogs, derived from the related precursor class of compounds having the formula III, generally referred to as “tetralones”
where R1=hydrogen, fluoro, chloro, bromo, trifluoromethyl, and alkoxy of 1 to 3 carbon atoms, R2 has the structure
where X and Y are selected from the group consisting of hydrogen, fluoro, chloro, bromo, trifluoromethyl, cyano, and alkoxy of 1 to 3 carbon atoms, with at least one of X or Y being other than hydrogen. In a preferred embodiment, R1 is hydrogen, X is Cl, and Y is Cl.
The specific features of one generalized preparative route to sertraline and sertraline analogs, depicting only those features of central interest here, are given in equation (1):
The conversion shown in Equation 1 whereby chiral tetralones are transformed to the corresponding immines, followed by reduction thereof to N-substituted-(disubstituted phenyl)-1,2,3,4-tetrhydro-1-naphthaleneamines can be accomplished by methods known in the art. Unfortunately, such a synthetic route has the undesirable result of producing a mixture of cis and trans amine isomers in the form of a racemate upon reduction of the immine function, rather than the desired cis-N-substituted-(disubstituted-phenyl)-1,2,3,4-tetrhydro-1-naphthaleneamines. Thus, this synthesis requires separation of the isomeric sertraline racemate or isomeric sertraline analog racemate to produce the desired cis racemic sertraline or cis racemic sertraline analogs. This can then be followed by another separation of the cis racemic sertraline or cis racemic sertraline analogs to yield a cis sertraline enantiomer pair or a cis sertraline analog enantiomer pair. Then the desired sertraline or chiral sertraline analogs can be obtained from separation of the enantiomer pairs.
An advantage of our invention for preparing sertraline or chiral sertraline analogs is that racemic sertraline or sertraline analogs and their enantiomer pairs may be resolved without the need for expensive optically selective precipitating agents, and the undesired sertraline or sertraline analog enantiomers can be converted back to racemic sertraline or sertraline analogs and recycled to a resolution stage, as illustrated in FIGS. 1 and 2. Moreover, since simulated moving bed chromatography is a continuous process, quality control can be more effective and can be continuous in the context that separation parameters may be changed incrementally at frequent intervals.
Before describing the specifics of the processes in FIGS. 1 and 2 we will briefly review simulated moving bed chromatography. The advantages of the moving bed of adsorbent in a countercurrent separation process have long been recognized. Because of the difficulty of an actual moving adsorbent bed, a flow scheme has been devised which maintains the process features of continuous countercurrent flow of fluid and solid without the actual movement of solids-i.e., a simulated moving bed.
In simulated moving bed processes the adsorption and desorption operations are continuously occurring which allows both continuous production of an extract and a raffinate stream with the continual use of feed and desorbent streams. A preferred embodiment of this process utilizes what is known in the art as the simulated moving bed countercurrent flow system. The operating principals and sequence of such a flow system are described in U.S. Pat. No. 2,985,589.
Simulated moving bed chromatography is a flow scheme which has been devised which maintains the process features of continuous countercurrent flow of fluid and solid without actual movement of the solid. The simulated moving bed technique has been described in R. A. Meyers, Handbook of Petroleum Refining Processes , pages 8-85 to 8-87, McGraw-Hill Book Company (1986). The technique has been applied commercially to a number of processes such as a separation of p-xylene from C 8 aromatic isomers, the separation of linear paraffins from branched-chain and cyclic hydrocarbons, and a process to separate fructose and glucose from mixtures thereof, to name just a few.
Simulated moving bed chromatography may be readily applied to resolution of racemates simply by using a chiral adsorbent. See, e.g., M. Negawa and F. Shoji, J. Chrom. , 590, (1992), 113-7; M. J. Gattuso, B. McCullough, and J. W. Priegnitz presented at Chiral Europe '94 Symposium, Spring Innovations, Nice, France, Sep. 19-20, 1994.
A necessary feature of our invention is the adjustment of separation conditions to optimize the production of the desired enantiomer of high enantiomeric purity, i.e., optimize the formation of substantially pure desired enantiomer. By “substantially pure” is meant material of at least 95% enantiomeric purity, preferably at least 97% enantiomeric purity.
A specific embodiment involves the isomer conversion of undesired isomers and racemization of undesired enantiomers obtained by SMB isomer separation and resolution of the various mixtures. Any isomer conversion and racemization means proceeding at high yield and with good selectivity will suffice. Satisfaction of these requirements maximizes the utilization of racemic starting material while minimizing the overall process cost.
Referring to FIG. 1, the cis and trans amine isomers of sertraline or sertraline analog racemates are separated with the use of simulated moving bed chromatography using a chiral or non-chiral adsorbent to afford substantially pure cis racemic sertraline or cis racemic sertraline analogs. In a second step the cis racemic sertraline or cis racemic sertraline analogs are separated with the use of simulated moving bed chromatography using a chiral adsorbent to afford sertraline enantiomer pairs or sertraline analog enantiomer pairs. The desired enantiomer can then be separated from the enantiomer pair with the use of simulated moving bed chromatography using a chiral adsorbent to afford sertraline or chiral sertraline analogs. In one or several steps the undesired isomers can then be converted to mixtures of cis and trans isomers by isomerization and the undesired enantiomers can be racemized, with subsequent recycle an appropriate preceding resolution stage. FIG. 2 illustrates an example of a process in which sertraline or sertraline analogs are produced with the use of simulated moving bed chromatography using a chiral adsorbent to afford separation of enantiomers followed by isomer conversion without racemization, and recycle of the resulting cis and trans isomers of the undesired enantiomer to the separation stage.
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Improved processes for preparation of sertraline or sertraline analogs in high enantiomeric purity centers on resolution using simulated moving bed chromatography of isomeric racemic sertraline or sertraline analogs. Resolution is effected with high enantiomeric purity, and the undesired enantiomer may be racemized and recycled to the resolution phase to avoid loss.
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BACKGROUND
One of the major problems in hypodermic syringe construction is the needle hub which forms a connecting unit between a hypodermic syringe barrel and a puncturing cannula. Numerous types of hub designs have been proposed to provide reliable and very firm connection between the cannula and the needle hub. The hub must also provide a very reliable seal with the syringe barrel's tapered adapter. Different materials have been used in the past for needle hubs. Polypropylene has been used for hubs, but has very little adherence to epoxies or other adhesives used to join the hub and cannula. Because of this shortcoming of polypropylene, various attempts have been made to mechanically anchor the epoxy to the hub. Epoxy will bond readily to the metal cannula, but not to the polypropylene hub. Difficult to mold undercut pockets have been proposed in U.S. Pat. No. 3,179,107, as well as expensive separate holding sleeves as in U.S. Pat. No. 3,472,227. Various other types of crimped anchoring structure such as in U.S. Pat. No. Re. 28,713 and 2,844,149 have been proposed for securing a metal cannula to a thermoplasitc needle hub.
Nylon has also been used in hubs because it has very good adherent properties to epoxy. No expensive undercut structure was required in the nylon hub. However, nylon tends to readily absorb moisture when subjected to elevated temperatures or humid environments and such absorbed moisture tends to slightly alter the hub's dimensional configuration, sometimes causing the hub to become loosened on the tapered adapter of the syringe barrel during long storage periods.
SUMMARY OF THE INVENTION
The problems of polypropylene and nylon hubs explained above have been overcome by the present invention which has unexpectedly found that a polycarbonate needle hub can form a very secure fit over long periods of time with a syringe barrel's tapered adapter of a material substantially softer than the polycarbonate without crazing or stess cracking the polycarbonate hub. This is because the softer barrel adatper cold flows very slightly under compressive forces to prevent long term crazing or stress cracking of the polycarbonate hub which is under hoop stress. The polycarbonate hub is extremely adherent to epoxy for anchoring the cannula to the hub.
A related application entitled "Syringe With Plug Type Needle Hub Lock," Ser. No. 953,608, filed Oct. 23, 1978, has a sealing portion of a hub under compression hoop stresses, and is very well suited for small size insulin syringes of lcc size or smaller.
THE DRAWINGS
FIG. 1 is a sectional view of a protector encased needle assembled to a syringe barrel;
FIG. 2 is a sectional view illustrating separational pull forces used to test the holding power between the hub and syringe; and
FIG. 3 is an enlarged view of the epoxy pocket in the hub.
DETAILED DESCRIPTION
FIG. 1 shows a needle hub 1 of polycarbonate having an internal tapered section 2 that can be in the form of a standard Luer taper. A cannula 3 is secured to a forward end of the hub by an adhesive, such as an epoxy, 4. No undercuts are needed in the hub as shown in the enlarged view of FIG. 3. During pull tests, it was unexpectedly found that the epoxy to the polycarbonate and cannula bond was so good that it took approximately 30 lbs. of force to separate the cannula and hub. This is well in excess of what is normally considered safe. A protector 5 is removably mounted on hub 1.
A syringe barrel 6 has externally tapered adapter 7 of a material softer than polycarbonate. It has been unexpectedly found that such interconnecting relationships between these two materials solves a crazing or stress cracking problem that is well-known to exist with polycarbonate materials. When a very hard polycarbonate material is under stress for extended periods of time, the material develops small surface cracks known as crazing. If the cracks proceed completely through the part, they are known as stress cracks. Such crazing or stress cracking is believed to be due to the cyrstalline structure of polycarbonate.
Crazing or stress cracking of a polycarbonate hub would not normally be a problem with hubs that are sold separately from the syringe barrel and assembled immediatedly prior to injection. Crazing and stress cracking occur over long periods of time, such as several days or months. Many of the hypodermic syringes sold today are sold with a preconnected needle, and since such hub is under continual stress during warehouse storage, shipments, etc., it would be expected that crazing and stress cracking would render a polycarbonate hub unsuitable.
The applicants have unexpectedly found that the soft polypropylene adapter of the syringe barrel overcomes such crazing and stress cracking problems which still occur with the polycarbonate hub stored for long periods of time on a glass adapter which does not cold flow with extended compressive forces.
Comparative tests were made between nylon, polypropylene, and polycarbonate relative to the force necessary to separate a syringe barrel from a needle after such needle is applied with a staking force of 20 lbs. It was shown that the polycarbonate hub was substantially better than the other two. The results of pull forces both before and after autoclaving are summarized below.
______________________________________ Befoe Autoclaving After Autoclaving______________________________________Nylon 5 lbs. 2 lbs.Polypropylene 8 lbs. 3 lbs.Polycarbonate 9 lbs. 4 lbs.______________________________________
While the above tests were made with syringes not having a threaded collar in addition to the tapered adapter, such as shown in U.S. Pat. No. 3,301,256, the higher retention forces of polycarbonate would have advantages for such collared syringe because such high retention forces would prevent inadvertent unscrewing removal of the hub from the collared syringe.
The applicants have also found that it is important during the manufacturing procedure of the syringe barrel and needle hub to attach the hub to the syringe barrel adapter prior to any substantial compressive forces being applied to the adapter. Thus, to avoid any crazing and stress cracking problems, the polycarbonate hub should make the virgin connection to the syringe. It has been noted that syringes that have been stored for a considerable time with one polycarbonate hub will not perform the crazing protection to a substitute polycarbonate hub fitted to such syringe. This is believed to be due to substantially all of the cold flow having occurred in the barrel adapter and there was substantially no cold flow left to protect the second polycarbonate hub. Thus, a previously stored polypropylene syringe barrel acts somewhat like a glass barrel when attached to the polycarbonate hub.
In the foregoing description, a specific example has been used to describe the invention. It is understood by those skilled in the art that certain modifications can be made to this example without departing from the spirit and scope of the invention.
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A hypodermic needle having a hub of polycarbonate which is extremely adherent to an epoxy for securing a cannula to the hub. A syringe barrel adapter of a material softer than polycarbonate; i.e., polypropylene, is wedge fitted to the hub and compressively cold flows slightly during storage to prevent long term crazing or stress cracking of the polycarbonate hub.
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RELATED APPLICATIONS
[0001] This application is a divisional of and claims the benefit of U.S. application Ser. No. 10/904,071, titled “HARVESTING VIBRATION FOR DOWNHOLE POWER GENERATION,” filed Oct. 21, 2004, the contents of which are herein incorporated by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The invention generally relates to harvesting vibration for downhole power generation.
[0004] 2. Description of the Related Art
[0005] The following descriptions and examples are not admitted to be prior art by virtue of their inclusion in this section.
[0006] A typical subterranean well includes various devices that are operated by mechanical motion, hydraulic power or electrical power. For devices that are operated by electrical or hydraulic power, control lines and/or electrical cables typically extend downhole for purposes of communicating power to these tools from a power source that is located at the surface. A potential challenge with this arrangement is that the space (inside the wellbore) that is available for routing various downhole cables and hydraulic control lines may be limited. Furthermore, the more hydraulic control lines and electrical cables that are routed downhole, the higher probability that some part of the power delivery infrastructure may fail. Other risks are inherent in maintaining the reliability of any line or cable within the well's hostile chemical, mechanical or thermal environment and over the long length that may be required between the surface power source and the downhole power operated device.
[0007] Thus, some subterranean wells have tools that are powered by downhole power sources. For example, a fuel cell is one such downhole power source that may be used to generate electricity downhole. The subterranean well may include other types of downhole power sources, such as batteries, for example.
[0008] A typical subterranean well undergoes a significant amount of vibration (vibration on the order of Gs, for example) during the production of well fluid. In the past, the energy produced by this vibration has not been captured. However, an emerging trend in subterranean wells is the inclusion of devices to capture this vibrational energy for purposes of converting the energy into a suitable form for downhole power.
[0009] Thus, there is a continuing need for better ways to generate power downhole in a subterranean well.
SUMMARY
[0010] In an embodiment of the invention, a system that is usable with a subterranean well includes a winding, a member and a circuit. The winding is located downhole in the well, and the member moves relative to the winding in response to vibration occurring in the well to cause a signal to be generated on the winding. The circuit is coupled to the winding to respond to the signal to provide power to operate a component located downhole in the well.
[0011] Advantages and other features of the invention will become apparent from the following description, drawing and claims.
BRIEF DESCRIPTION OF THE DRAWING
[0012] Certain embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying drawings illustrate only the various implementations described herein and are not meant to limit the scope of various technologies described herein. The drawings are as follows:
[0013] FIG. 1 is a schematic diagram of a well according to an embodiment of the invention;
[0014] FIG. 2 is a flow diagram depicting a technique to generate downhole power according to an embodiment of the invention;
[0015] FIGS. 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 and 14 depict mechanisms to enhance the generation of downhole vibrational energy according to an embodiment of the invention;
[0016] FIG. 15 depicts a system located on a sandscreen to aid in the generation of downhole power according to an embodiment of the invention;
[0017] FIG. 16A is a flow diagram depicting a technique to power wireless tags according to an embodiment of the invention;
[0018] FIG. 16B depicts a system to deploy wireless tags according to an embodiment of the invention;
[0019] FIG. 17 is a schematic diagram of a wireless tag according to an embodiment of the invention;
[0020] FIG. 18A is a block diagram of a system to harness and store vibrational energy downhole according to an embodiment of the invention;
[0021] FIG. 18B depicts a piezoelectric material based vibration energy converter;
[0022] FIG. 19A is a block diagram of an electromagnetic based system to harness and store vibrational energy downhole according to an embodiment of the invention;
[0023] FIG. 19B depicts an electromagnetic based vibration energy converter;
[0024] FIGS. 20A , 20 B and 20 C are schematic diagrams of vibrational energy harvesting mechanisms according to an embodiment of the invention;
[0025] FIG. 21 is a schematic diagram of a portion of a drilling string according to an embodiment of the invention;
[0026] FIG. 22 is a schematic diagram of a subsea well according to an embodiment of the invention;
[0027] FIG. 23 is a flow diagram depicting a technique to power a downhole tool according to an embodiment of the invention;
[0028] FIG. 24 is a flow diagram depicting a technique to use vibration in a cementing operation according to an embodiment of the invention;
[0029] FIG. 25 is a flow diagram depicting a technique to evaluate potential blockage of a downhole pipe according to an embodiment of the invention;
[0030] FIG. 26 is a flow diagram depicting a technique to communicate with a downhole tool according to an embodiment of the invention;
[0031] FIG. 27 is a schematic diagram depicting a system in which vibrational energy is used to communicate with downhole tools according to an embodiment of the invention; and
[0032] FIGS. 28 , 29 and 30 are schematic diagrams of mechanisms to harness vibrational energy to generate electrical power according to embodiments of the invention.
DETAILED DESCRIPTION
[0033] In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. In the specification and appended claims: the terms “connect”, “connection”, “connected”, “in connection with”, “connecting”, “couple”, “coupled”, “coupled with”, and “coupling” are used to mean “in direct connection with” or “in connection with via another element”; and the term “set” is used to mean “one element” or “more than one element”. As used herein, the terms “up” and “down”, “upper” and “lower”, “upwardly” and downwardly”, “upstream” and “downstream”; “above” and “below”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments of the invention.
[0034] Referring to FIG. 1 , an embodiment 10 of a well in accordance with the invention includes a tubular string 14 (a production string, for example) that extends into a wellbore of the well 10 . The tubular string 14 may include a central passageway 29 that communicates a flow 27 from a subterranean formation zone 32 (or to a formation zone in the case of an injection well). The zone 32 represents one out of many possible zones of the well 10 . The zone 32 may be defined (i.e., isolated from other zones) by one or more packers 30 (one being depicted in FIG. 1 ).
[0035] The flow 27 is a primary source of vibrational energy downhole, and this vibrational energy is captured by a vibrational energy harvesting mechanism 20 (of a power generation tool 18 ) for purposes of converting the vibrational energy into downhole electrical power. This electrical power, in turn, may be used to power one or more downhole power-consuming components, such as sleeve valves, ball valves, motors, actuators, sensors, sound sources, electromagnetic signaling sources, or equipment to fire “smart bullets” into a well casing, perforating gun firing heads, controllers, microprocessors, Micro Electrical Mechanical Sensors (MEMS), telemetry systems (transmitters or receivers), etc., depending on the particular embodiment of the invention.
[0036] In some embodiments of the invention, the string 14 includes one or more features to enhance the generation of vibrational energy, referred to generally herein as a “vibration enhancement mechanism 16 .” More specifically, the flow 27 enters the mechanism 16 that, in some embodiments of the invention, produces a locally more turbulent flow 31 that flows uphole. The creation of this more turbulent flow, in turn, amplifies the vibrational energy, thereby leading to the increased production of downhole power. The vibrational harvesting mechanism 20 may be located in proximity to (within ten feet, for example) to the vibration enhancing mechanism 16 , in some embodiments of the invention. Various embodiments of the vibration enhancing mechanism are described below.
[0037] Thus, referring to FIG. 2 , in some embodiments of the invention, a technique 40 may be used to harvest vibrational energy downhole. More specifically, in accordance with the technique 40 , the downhole vibration is enhanced (block 42 ) such as by the vibration enhancement mechanism 16 , as further described below. Next, pursuant to the technique 40 , the downhole vibration is converted (block 44 ) into downhole power to power one or more downhole power-consuming devices.
[0038] As a more specific example, FIG. 3 depicts a cross-section of a vibration enhancing mechanism 50 in accordance with an embodiment of the invention. The device 50 may be formed from a section of the string 14 having an interior wall 15 that constricts the central passageway 29 of the string 14 . More specifically, in some embodiments of the invention, the section has a circular cross-section of varying diameter; and in some embodiments of the invention, the section forms a Venturi-type flow path. This flow path, in turn, converts the entering flow 27 into a more turbulent flow 31 for purposes of creating more vibration. The flow path of the device 50 thus creates vibrational energy that is harvested by the power generator tool 18 .
[0039] Other types of vibration enhancing mechanisms may be used in other embodiments of the invention. For example, referring to a cross-section depicted in FIG. 4 , in some embodiments of the invention, a cantilevered member 56 may extend from the interior wall 15 of the string 14 into the central passageway 29 . The member 56 introduces an obstruction in the flow path 27 to create the more turbulent flow 31 .
[0040] As another example, FIG. 5 depicts a cross-sectional view of a vibration-enhancing mechanism 60 that contains a flexible member 62 that has one end that is attached to the interior wall 15 of the tubular string 14 and another free end that extends into the central passageway 29 . Due to this arrangement, the flexible member 62 moves in response to the flow 27 to create the more turbulent flow 31 and thus, enhance the generation of vibrational energy.
[0041] As another example, FIG. 6 depicts a cross-sectional view of a vibration-enhancing mechanism 66 that, similar to the Venturi-type flowpath of the mechanism 50 ( FIG. 3 ), includes a restricted flow path 68 for purposes of increasing vibration downhole. In some embodiments of the invention, the flow path 68 has a circular cross-section section that varies in diameter.
[0042] It has been discovered that a production string (a possible embodiment of the tubing string 14 ( FIG. 1 )) has a fundamental vibration mode in which the cross-section of the production string expands and contracts in two orthogonal cross-sectional directions. For example, as depicted in a cross-section of a production tubing section in FIG. 7 , during the flow of fluid through a production tubing string, the string may include a cross-section that expands in the positive and negative Y directions while the cross-section of the production tubing contracts in the positive and negative X directions. Next, pursuant to the fundamental vibration mode, the cross-section of the production tubing expands in the positive and negative X directions and contracts in the positive and negative Y directions. This process repeats to establish the fundamental vibration mode.
[0043] As depicted in FIG. 7 , in some embodiments of the invention, the thickness of the wall of the production string 70 may be radially varied to select the axis and otherwise enhance the fundamental vibration mode. More specifically, the cross-section of the string may include thinner portions 72 that extend along the X-axis and thinner portions 74 that extend along the Y-axis. The remaining portions 76 of the cross-section are thicker. Thus, due to this arrangement, the flexing of the production string 70 in the above-described cross-sectional directions is enhanced due to the thinning of the production tubing string cross-section in orthogonal directions. Increasing the flexing of the production tubing string, in turn, enhances the vibrational energy that is generated by the flow of fluids through the production tubing string. Thus, the arrangement that is depicted in FIG. 7 enhances the vibrational energy that is converted into electrical energy downhole.
[0044] As another example of a mechanism to enhance vibrational energy downhole, FIG. 8 depicts a mechanism 80 that includes a spring 81 that may be attached to, for example, the interior wall 15 of the string 14 and extend into the central passageway 29 . In yet another embodiment of the invention, a vibration enhancing mechanism 84 (a cross-section of which is depicted in FIG. 9 ) includes a wedge-shaped flow diverter 86 that is inserted into the flow path 27 for purposes of creating a more turbulent flow. As depicted in FIG. 9 , regions 88 exist between the diverter 86 and the wall of the string 14 for purposes of allowing fluid to pass therethrough. However, the flow diverter 86 introduces additional turbulence into the flow 27 , thereby creating additional vibration downhole.
[0045] In some embodiments of the invention, a piece of downhole equipment that may already be located downhole may be strategically placed near the power generation tool 20 ( FIG. 1 ) for purposes of enhancing vibration near the tool 20 . For example, referring to FIG. 10 , a multiphase mixer 86 may be placed in close proximity (within ten feet for example) to the power generation tool 20 . The multiphase mixer 86 , as its name implies, typically is used in production to blend various phases of well fluid together. The mixer 86 may include, for example, an opening 102 that receives the flow 27 . The mixer 86 may also include an internal chamber 99 that includes various orifices 100 through which the flow may proceed to flow upstream and produce the flow 31 through the central passageway 29 .
[0046] In other embodiments of the invention, a vibrational energy-enhancing mechanism 108 (a cross-section of which is depicted in FIG. 11 ) may be used. The mechanism 108 includes a blind T 112 that is inserted into the flow path 27 . The blind T 112 is surrounded by openings 110 that permit the flow of the fluid around the blind T 112 . However, the inclusion of the blind T 112 in the flow path 27 creates turbulence that, in turn, enhances the vibrational energy downhole.
[0047] Referring to FIG. 12 , in some embodiments of the invention, a vibration-enhancing section 120 of the string 15 may include a spiral or helical groove 124 that extends along the inner surface of the wall 15 of the string 14 . As depicted in FIG. 12 , the longitudinal axis of the groove 124 is concentric with the longitudinal axis of the string 14 .
[0048] In some embodiments of the invention, a free flowing part may be used to enhance the generation of vibrational energy downhole. For example, a vibration enhancing mechanism 130 (a cross-section of which is depicted in FIG. 13 ) may include a chamber 132 (in the flow path 27 ) that contains a ball 140 . Analogous to a policeman's or an umpire's whistle, the ball 140 is trapped inside the chamber 132 , in that lower 139 and upper 135 openings in the chamber 132 are sized to permit fluid (but not the ball 140 ) to pass into and out of the chamber 132 and contact the ball 140 . The interaction of the fluid with the ball 140 creates vibrational energy that may be harvested for electrical power.
[0049] In some embodiments of the invention, an electrical device that consumes harvested power downhole may also be used to generate vibrational energy used for purposes of power generation. For example, as depicted in FIG. 14 , in some embodiments of the invention, a vibration-enhanced mechanism 150 may include an electrical pump 152 (a beam-type pump, a rod-type pump or an electrical submersible pump (ESP)), as just a few examples. The electrical pump 152 receives the flow 27 to produce the output flow 31 . The operation of and fluid flow through the pump 152 enhances the vibrational energy.
[0050] Although the vibration-enhancing mechanisms and power generating mechanisms (such as the power generator tool 18 ) that are described above are generally located in the central passageway of the string 14 , it is noted that in other embodiments of the invention, these mechanisms may be located in other regions of the well. For example, in some embodiments of the invention, these mechanisms may be located on the outside of the string 14 or located in a side packet mandrel, as further described below in connection with FIG. 22 .
[0051] As a more specific example, referring to FIG. 15 , in some embodiments of the invention, a vibration-enhancing mechanism 160 may be located on the outside of a sandscreen 158 . Thus, the mechanism 160 , which may be any of the above-described mechanisms, may be located in a flow path located between the exterior and the interior of the sandscreen 158 . In some embodiments of the invention, the mechanism 160 may be located inside the sandscreen 158 . Furthermore, in some embodiments of the invention, a power generator (not shown) to generate electrical power from vibrational energy may be mounted to the sandscreen 158 and may be located either on the outside or inside of the sandscreen 158 .
[0052] Although in the embodiments described above, the power generation mechanism 20 is depicted ( FIG. 1 ) as being attached to the string 14 , in other embodiments of the invention, the power generation mechanism 20 may not be fixed in position relative to the string 14 . For example, in some embodiments of the invention, a wireless (a radio frequency (RF), for example) tag may be used to measure various properties in a subterranean well. These properties may include, for example, detection of water or chemical constituents, such as hazardous H2S, or measurement of pressure and temperatures at various positions in the well. The tag may be free-flowing, in that the tag may be released into the well and take a measurement at a particular depth in the well. Many variations are possible. For example, the tag may be activated at a particular depth, a particular temperature, a particular pressure, etc.
[0053] For purposes of supplying power to the tag, the tag may derive its power from the vibrational forces that are experienced by the tag itself. Thus, instead of being attached to a static structure, such as the string 14 , for example, the tag is free-flowing and is imparted with vibrational energy as the tag flows in the well. This vibrational energy, is converted by a vibrational energy transformer of the tag into electrical power for the tag.
[0054] Thus, referring to FIG. 16A , in some embodiments of the invention, a technique 180 includes deploying (block 182 ) wireless tags in a subterranean well. Vibrational energy is used (block 184 ) to activate (i.e., power up and continue providing power to) the tags. Once activated, measurements are then performed (block 186 ) with the tags.
[0055] FIG. 16B depicts a subterranean well 200 in accordance with the technique 180 . As shown in FIG. 16B , the well 200 may include a tubular string 204 (a production tubing, for example) into which several tags 220 have been placed into the central passageway of the well 200 . As an example, the well 200 may include a surface pump 206 that may control the flow of fluid through the well 200 . For example, the pump 206 may halt fluid flow through the string 204 to allow the tags 220 to descend into the well 200 . When the tags have collected the data, the pump 206 may then be re-activated to cause fluid to flow uphole and thus return the tags 220 toward the surface.
[0056] In some embodiments of the invention, the well 200 may include a tag reader 230 to extract information from the tags 220 as the tags 220 return from downhole. As the tags 220 descend downhole, vibrational energy imparted on the tags 220 generate power on the tag 220 to activate the tag 220 so that the tag 220 may then take the appropriate measurement downhole.
[0057] Referring to FIG. 17 , in some embodiments of the invention, the tag 220 may have an architecture that is generally depicted in FIG. 17 . This architecture may include, for example, a processor 248 that is coupled to a sensor 250 (a pressure or temperature sensor, for example) through a bus 249 . The processor 248 may execute instructions that are stored in a memory 244 (also coupled to the bus 249 ) as well as store data from the sensor 250 in the memory 244 . The architecture may include various other features, such as a transmitter to transmit to the reader 230 ( FIG. 16B ), depending on the particular embodiment of the invention.
[0058] As depicted in FIG. 17 , the tag 220 includes power generation circuitry that includes, for example, a vibrational energy converter 240 . As its name implies, the converter 240 produces a voltage (for example) in response to vibrational energy that occurs to the tag 220 . A DC-to-DC converter 242 converts this voltage into a regulated voltage that appears on voltage supply lines 246 . The voltage supply lines 246 , in turn, furnish power to the various components of the tag 220 , such as the sensor 250 , processor 248 and memory 244 , as just a few examples.
[0059] In some embodiments of the invention, the tag 220 may include a reserve energy source, such as a battery 245 , that is coupled to the output terminals of the DC-to-DC converter 242 . The battery 244 serves as an energy buffer to store excess energy that is provided by the converter 240 so that this energy may be used to regulate the power that is provided to the power-consuming components of the tag 220 .
[0060] In some embodiments of the invention, the power harvesting circuitry (whether on a wireless tag or affixed to the string 14 ) may have an architecture 260 that is generally depicted in FIG. 18A . This architecture 260 includes a vibration responsive strain inducer 264 . As examples, the vibration responsive strain inducer 264 produces a mechanical force that, as its name implies, imparts a physical strain on a piezoelectric material 262 . A piezoelectric material, by its very nature, produces a terminal voltage responsive to the strain that is induced on the material. Therefore, in response to the strain produced by the inducer 264 , the piezoelectric material 262 produces a voltage that appears on a signal line 266 . This voltage, in turn, is regulated to a specific DC level by a DC-to-DC converter 268 to produce a regulated voltage that appears on a power supply 270 .
[0061] Thus, the inducer 264 , piezoelectric material 262 and converter 268 form a basic power-harvesting generator 273 in accordance with an embodiment of the invention.
[0062] Although depicted in FIG. 18A as producing DC power, it is noted that in other embodiments of the invention, the generator 273 may include an inverter for purposes of generating an AC voltage. Thus, other embodiments are within the scope of the following claims.
[0063] Additionally, in some embodiments of the invention, a particular well may include several generators 275 that are connected in parallel to the supply 270 . Furthermore, in some embodiments of the invention, a battery 272 may be coupled to the voltage supply line 272 for purposes of serving as an energy buffer to absorb and supply power, depending on the particular vibrational energy being experienced at the time.
[0064] In accordance with an embodiment of the invention, the vibration responsive strain inducer 264 and piezoelectric material 262 may, in some embodiments of the invention, have a form 280 that is depicted in FIG. 18B . More specifically, the arrangement 280 may include a piezoelectric material 282 that is located between fairly rigid members 286 and 284 . These members may be formed from, as examples, part of housing of the string 14 as well as explicit plates. A cantilevered mass 290 is connected to the plates 284 and 286 to exert a strain force on the piezoelectric material 282 in response to the vibrational energy sensed by the mass 290 . Thus, vibrational energy causes movement of the mass 290 , and this movement, in turn, induces stress to cause the piezoelectric material to generate a corresponding voltage.
[0065] Referring both to FIGS. 19A and 19B , in some embodiments of the invention, the power harvesting circuitry (whether on a wireless tag or affixed to the string 14 ) may have an architecture 260 that is generally depicted in FIG. 19A . This architecture 260 includes a vibration responsive strain inducer 264 . As examples, the vibration responsive strain inducer 264 produces a mechanical force that, as its name implies, imparts a physical strain on an electromechanical energy conversion, or generator, that is depicted, as an example, in FIG. 19B . An electromagnetic energy converter, by its very nature, produces a terminal voltage induced by an electrical conductor, or coil, moving in a magnetic field that is maintained by a suitable ferro-magnetic material, permanent magnet. Therefore, in response to the strain or motion produced by the inducer 264 , the electromagnetic converter produces a voltage that appears on a signal line 266 . This voltage, in turn, is regulated to a specific DC level by a DC-to-DC converter 268 to produce a regulated voltage that appears on a power supply 270 .
[0066] In the various embodiments of the invention, the mass that induces the strain on the piezoelectric material may not be a cantilevered mass but alternatively, may be another type of strain inducer that generates a strain on the piezoelectric material in response to vibrational energy. For example, in some embodiments of the invention, the wall of the tubular string 14 (see FIG. 1 ) may be lined with a piezoelectric coating 304 , as depicted in FIG. 20A . More specifically, the piezoelectric material lining 304 may completely or partially coat the interior wall of the tubular string 14 , according to the particular embodiment of the invention. Due to the above-described fundamental mode of vibration of the tubular string 14 , this vibration induces a strain on the piezoelectric material coating 304 to generate a corresponding voltage across the material 304 .
[0067] Although not depicted in FIG. 20A , in some embodiments of the invention, a thin insulation layer may be interposed between the lining 304 and the interior surface of the tubing string wall for purposes of isolating the terminal voltage appearing on the coating 304 from the tubing string 14 .
[0068] As another example of a strain-inducing mechanism in accordance with the invention, FIG. 20B depicts a mechanism 304 that includes a flexible flow member 62 (see FIG. 5 ) that has a piezoelectric electric coating 308 lining the flexible member 62 . Thus, the motion of the flexible member 62 induces a strain on the material 308 to generate a voltage on the material 308 .
[0069] Thus, as can be seen, the piezoelectric coating may be applied to various downhole components that are subject to vibration, in that the vibration induces a strain on the piezoelectric coating, and this strain induces a voltage that may be converted into downhole power. As yet another example, FIG. 20C depicts the blind T 112 (see FIG. 11 ) that is at least partially covered by a piezoelectric coating 311 . Thus, other variations are possible and are within the scope of the appended claims.
[0070] Due to the generation of electrical power downhole, various control lines and electrical cables do not need to be extended from the surface of the well. Furthermore, generating electrical power downhole may be advantageous for purposes of reducing cabling between downhole components. For example, FIG. 21 depicts a drill string 320 that includes a mud motor 324 and a drill bit 328 . The drill string 320 may include sensors 326 that are used for purposes of monitoring operation of the drill string 320 and monitoring general operation of the drilling. The sensors 326 typically are located close to the drill bit 328 . A particular challenge with this arrangement is that the sensors 326 may be located away from a power source and thus, electrical cables may have to span across the mud motor 324 for purposes of delivering power to the sensors 326 . However, in accordance with embodiments of the invention, the sensors 326 may be in close proximity to power generation circuitry 324 that generates electrical power from the vibration of the drill string 320 , such as the vibration that occurs during operation of the mud motor 324 . Due to this arrangement, cabling does not have to be extended across the mud motor 324 for purposes of delivering power to the sensors 326 .
[0071] Referring back to FIG. 1 , as another example of the reduction of cabling due to the generation of power downhole, the well 10 may include an intelligent completion, a completion that contains circuitry that automatically controls downhole equipment independently from any commands that are communicated from the surface of the well. For example, the string 14 may be a production string and include a valve 21 (a sleeve valve or ball valve, as examples) that is electrically operated by power that is produced by the power generator tool 18 . An intelligent controller 23 of the string 14 may, for example, use a sensor 11 (also of the string 14 ) to detect one or more characteristic(s) of the flow 27 . The sensor 11 may include one or more of a pressure sensor, a temperature sensor, a fluid composition sensor and a Micro Electrical Mechanical Sensor (MEMS), depending on the particular embodiment of the invention.
[0072] Based on the detected characteristic(s), the controller 23 operates a valve 21 (a sleeve valve or ball valve, as examples) to control the flow 27 . For example, the controller 23 may determine the flow 27 has a high water content level and close the valve 21 to shut off flow from the zone 32 . As another example, the controller 23 may also control the valve 21 to regulate a pressure in the well. The controller 23 , sensor 11 and valve 21 , in some embodiments of the invention, receive power from the power generator tool 18 . In some embodiment of the invention, the controller 23 , sensor 11 and valve 21 receive all of their operating power from the power generating tool 18 .
[0073] As another example of a power consuming device that may rely on energy derived from vibrational energy downhole, FIG. 22 depicts a subsea well 400 that extends beneath a sea floor 402 . The subsea well 400 includes a subsea well tree and wellhead 404 ; and a tubular string 406 that extends into a wellbore of the well. A robot 414 may be located inside the tubular string 406 . The robot 414 may generally be autonomous in that the robot 414 does not rely on a tethered connection for purposes of operating in the subsea well to perform an intervention, for example. Thus, for purposes of generating power, robot 414 may dock to power connectors that are electrically coupled to a power generation mechanism 410 that generates downhole electrical power from vibrational energy.
[0074] As an example, the power generation mechanism 410 may be located in a side pocket mandrel 412 that is formed in the tubing 406 . As shown in FIG. 2 , due to the inclusion of the power generating mechanism 410 and the side pocket mandrel 412 , the central passageway of the tubing string 406 is unobstructed for purposes of operating the robot 410 , performing an intervention with other tools, producing well fluid, etc.
[0075] The subsea well 400 may include other components that are powered by the power generating mechanism 410 , such as, for example, telemetry circuitry 420 that is located on the sea floor 402 and is used to communicate (via acoustic, optical or electromagnetic communication, as examples) with a surface platform (not shown in FIG. 22 ). The power generating mechanism 410 may also deliver power (via communication lines 425 ) to electrical storage 424 (a battery, for example) that is located on the sea floor 402 .
[0076] The above-described arrangements rely on the vibrational forces that are produced either by downhole equipment or by the flow of well fluid in contact with a particular vibration-enhancing mechanism. However, in some embodiments of the invention, vibrations may be intentionally introduced into a fluid or slurry that is introduced downhole from the surface.
[0077] For example, FIG. 23 depicts an embodiment of a technique 430 in accordance with the invention, which uses vibrations in a gravel pack flow for purposes of communicating vibrational energy downhole that may be used to produce downhole power. More specifically, in accordance with the technique 430 , vibrations are induced in a gravel packed flow, as depicted in block 432 . For example, these vibrations may be induced by pressure pulses that are applied to a slurry flow as well as less regulated vibrational energy that is applied to the flow. Regardless of the specific form of the vibrational energy, the vibrational energy is applied at the surface of the well and is communicated downhole via the flow. Pursuant to the technique 430 , this vibrational energy is used (block 434 ) to generate downhole power, such as for a downhole tool to be used during or after the completion of gravel packing (for example).
[0078] Referring to FIG. 24 , other types of downhole flows may be used for purposes of communicating vibrational energy downhole. For example, FIG. 24 depicts a technique 444 for purposes of communicating vibrational energy via a cement flow. Pursuant to the technique 444 , a vibration is introduced in the cement flow, as depicted in block 446 . Similar to the gravel packed flow discussed in connection with FIG. 23 , vibrational energy may be imparted to the cement flow by, for example, pulses or other types of vibrational energy. This vibrational energy is then used to generate power downhole (as depicted in block 450 ) for one or more downhole tools.
[0079] Not only may the vibrational energy be used to produce downhole power, other uses of the vibrational energy may be used, in accordance with particular embodiments of the invention. For example, FIG. 25 depicts a technique 470 for purposes of using vibrational energy to detect problems with tubular passageways (production tubing passageways, gravel packing shunt tubes, etc.) downhole. In this manner, pursuant to the technique 470 , vibrational energy is detected (block 472 ) downhole and then used to evaluate (block 474 ) possible blockage in response to the detected energy. The vibrational energy may be generated downhole (in response to a fluid flow, for example) and/or may be communicated downhole by a flow (a cement or gravel packing flow, as examples) from the surface of the well. As a more specific example, in some embodiments of the invention, a circuit may analyze the spectral components of the produced vibrational energy and based on comparing the computed spectral energy to reference patterns, may determine whether or not a blockage exists in a particular downhole member.
[0080] As yet another example of the use of vibrational energy to perform a function other than solely being converted into downhole power, a technique 481 , depicted in FIG. 26 , uses vibrational energy for purposes of communicating with the downhole tool. More specifically, pursuant to the technique 481 , vibrational energy is detected (block 482 ) downhole, and this detection is used (block 484 ) to handshake, that is to communicate commands and/or measurements with a specific downhole tool.
[0081] As a more specific example, FIG. 27 depicts a well 500 in accordance with the invention that includes a tubular string 582 that extends into a wellbore of the well 500 . The string 582 includes gas lift valves 584 that may be used for purposes of injecting gas for purposes of lifting production fluid uphole. A circuit 590 on the surface of the well 500 monitors vibrational energy that is generated by the gas lift valves 584 for purposes of determining when a particular gas lift valve 584 has been activated. In this regard, in some embodiments of the invention, each gas lift valve 584 may be designed to have a unique and identifiable resonant frequency when activated. This vibrational frequency, in turn, is detected by the circuit 590 for purposes of identifying when the gas lift valve 584 has activated.
[0082] Alternatively, in some embodiments of the invention, each gas lift valve 584 may be designed to release tags that contain a unique and identifiable code that can be communicated to a suitable circuit at the surface located as 590 in FIG. 27 .
[0083] Other embodiments are within the scope of the following claims. For example, many other techniques may be used to generate electric power from vibrational energy downhole. For example, in some embodiments of the invention, a capacitor may be used that has at least one plate that is mounted to a spring. A voltage may be stored on the capacitor so that by variation of the distance between the plates of the capacitor, a varying voltage is produced. This varying voltage, in turn, may be converted into power for a particular downhole tool.
[0084] As another example of a mechanism to generate power from downhole vibrational energy, FIG. 28 depicts, as a variation on the electromagnetic energy converter depicted in FIG. 19B a mechanism 600 that includes a coil 602 that generally circumscribes a magnetically-charged ferrous material 610 . The material 610 , in turn, may be mounted on springs 606 to move longitudinally along the axis of the coil 602 , as depicted in FIG. 28 . This movement of the material 610 , in turn, produces a voltage on the coil 602 and this voltage may be converted into downhole power. In some embodiments of the invention, the coil 602 may be embedded in a mandrel 604 that generally circumscribes the ferrous material 610 .
[0085] In another variation, FIG. 29 depicts a power generation mechanism 620 in which the mandrel 604 (that contains the coil 602 ) moves instead of the ferrous material 610 . More specifically, the ferrous material 610 may be relatively stationary; and the mandrel 604 is mounted on springs 624 . Thus, vibration causes movement of the mandrel 604 (and coil 602 ) with respect to the ferrous material 610 . This movement, in turn, induces a voltage on the coil 602 , and this voltage may be used to generate power downhole. It is noted that many other variations are possible in the various embodiments of the invention. For example, FIG. 30 depicts a mechanism 650 similar to the mechanism 600 except that the ferrous material 610 is mounted via springs 651 so that the ferrous material 610 moves laterally with respect to the coil 602 . This lateral movement, in turn, changes the magnetic permeability of the path inside the coil 602 to change the voltage that appear on the coil's terminals. As depicted in FIG. 30 , in some embodiments of the invention, the spring 651 may couple the ferrous material 610 to the inner side-walls of the mandrel 604 .
[0086] Other variations are possible. For example, in other embodiments of the invention, the ferrous material 610 may be distributed on a dynamo that rotates inside the coil 602 to generate voltage on the coil's terminals. The rotational speed of the dynamo increases with the level of vibration in the well.
[0087] While the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
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A system that is usable with a subterranean well includes a winding, a member and a circuit. The winding is located downhole in the well, and the member moves relative to the winding in response to vibration occurring in the well to cause a signal to be generated on the winding. The circuit is coupled to the winding to respond to the signal to provide power to operate a component located downhole in the well.
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RELATED APPLICATION
This patent application is a continuation-in-part of U.S. patent application Ser. No. 09/023,775 titled "Method For Cleaning Hydrocarbon-containing Greases And Oils From Fabric in Laundry Washing Applications" filed Feb. 13, 1998 now U.S. Pat. No. 6,080,713 which is a continuation-in-part of U.S. patent application Ser. No. 08/985077 titled "Method for Cleaning Hydrocarbon-Containing Soils from Surfaces" filed Dec. 4, 1997 now abandoned.
FIELD OF THE INVENTION
This invention is related generally to cleaning and, more specifically, to a method of cleaning hydrocarbon-containing greases and oils from fabric surfaces in laundry washing applications using an improved detergent composition.
BACKGROUND OF THE INVENTION
The removal of hydrophobic or hydrocarbon soils is an area of weakness within the laundry cleaning industry. It is well known that hydrocarbon-based greases and oils become embedded in fabric and are difficult to remove. The cost to clean fabrics stained with oily and greasy substances is increased because of the inherent difficulty in removing these types of soils. Often, multiple or repetitive washings are needed or required to achieve satisfactory cleaning.
Removal of oily and greasy stains is a particular problem for industry, where these stains are most likely to be encountered. For example, industrial uniforms, auto mechanic towels, and car wash drying rags are typically soiled with hydrophobic oils and greases.
Removal of oily, greasy stains is also a problem in the household laundry washing environment. Household laundry detergents typically are not specifically formulated to clean hydrocarbon-containing soils because they are less commonly encountered in the home. Accordingly, the surfactants and builders used to formulate household laundry detergents would not be expected to be as effective at removing oily and greasy soils such as motor oil.
An improved method of cleaning oily, greasy and other hydrocarbon-containing soils from fabrics which is both efficacious and cost effective and which can be performed using standard laundry washing machines would represent an important advance in the art.
OBJECTS OF THE INVENTION
It is an object of this invention to provide a method of cleaning hydrocarbon-containing greases and oils from fabric that overcomes some of the problems and shortcomings of the prior art.
Another object of this invention is to provide an improved method of cleaning hydrocarbon-containing greases and oils that includes a detergent composition with improved synergistic laundry cleaning capabilities.
It is also an object of this invention to provide a method of cleaning hydrocarbon-containing greases and oils from fabric which is particularly suited for use in automatic laundry-washing machines.
A further object of this invention is to provide a method of cleaning hydrocarbon-containing greases and oils from fabric which includes a detergent composition with a foam profile suitable for use in automated washing processes.
It is a further object of this invention to provide a method of cleaning hydrocarbon-containing greases and oils from fabric which is cost-effective.
Yet another object of this invention is to provide an improved method of cleaning hydrocarbon-containing soils that includes a detergent composition which can be prepared and used in a dilute form or as a 100% actives concentrate.
These and other important objects will be apparent from the following descriptions of this invention which follow.
SUMMARY OF THE INVENTION
The present invention is directed toward an improved method of removing hydrocarbon-containing greases and oils from fabrics in a laundry washing process. The invention is highly efficacious in removing these types of soils. Indeed, and as set forth in the Examples below, the constituents of the composition appear to have a synergistic effect in removing hydrocarbon-containing greases and oils from fabrics particularly in automated laundry processes. It is envisioned that one particularly useful application of the method of this invention would be, by way of example only, in cleaning oils (such as, for example, motor oils), and greases from industrial uniforms, towels and cloths used in industrial settings.
The invention comprises the steps of preparing a detergent composition and washing the fabric to be cleaned with the detergent composition in a laundering process. According to the method, the fabric is immersed with the detergent composition in water which has a pH of between about 6.5-10 and a temperature of about 28° C. to about 75° C. The fabric is then washed. During washing, the fabric is agitated for a period of time and during the agitation cycle or cycles the detergent solubilizes, removes and emulsifies the oily substance. Such emulsified substance is then drained away and removed when the detergent-containing water is discharged following the agitation cycle or cycles. Further substance removal occurs in the subsequent rinse cycle or cycles. Remaining emulsified hydrocarbon-containing material is removed as the fabric is rinsed with water during the rinse cycle thereby completing the washing process.
The detergent composition of the inventive method comprises from about 10 to 50% by weight of a polyalkoxylated amine and from about 90-50% by weight of a nonionic water-soluble surfactant. The polyalkoxylated amine has a general structural formula selected from the group consisting of: ##STR1## wherein R 1 is selected from an alkyl, aryl or alkylaryl group having between 6 and 22 carbon atoms, R 2 is from 0 to 7 moles of alkoxylated units, n is 0 or 1, R 3 and R 4 are each selected from H and from 1 to 15 moles of alkoxylated units such that R 3 and R 4 are not both H, and ##STR2## wherein R 5 is selected from an ally, aryl or alkylaryl group having between 6 and 22 carbon atoms, R 6 is from 0 to 7 moles of alkoxylated units, n is 0 or 1, R 7 , R 8 and R 9 are each selected from H and from 1 to 15 moles of alkoxylated units such that R 7 , R 8 and R 9 are not each H. Mixtures of the amines may be used.
A wide range of nonionic surfactants are useful in preparing the detergent compositions of the invention. Exemplary nonionic surfactants will be described in greater detail below.
As used throughout the specification and claims, terms such as "between 6 and 22 carbon atoms," C3 to C10 and C 1-5 are used to designate carbon atom chains of varying lengths and to indicate that various conformations are acceptable including branched, cyclic and linear conformations. The terms are further intended to designate that various degrees of saturation are acceptable. The inventive polyalkoxylated amines and the water soluble nonionic surfactants set forth above may be isolated or present within a mixture and remain within the scope of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The detergent composition of the invention may be prepared as a solid, liquid or gel in physical state or form using any conventional method. There is no particular order in which the constituents are combined. Liquid and solid forms of the invention require good dispersal of the constituents for maximum effectiveness. Solid forms of the composition may be prepared through known methods such as dry blending or spray drying in which the composition is applied to a dry substrate such as a zeolite.
It is expected, although not required, that the washing step will be performed by an automatic washing machine. The detergent composition may be applied to the fabric directly prior to immersion in the wash water or may be added directly to the wash water in any suitable manner or quantity.
As will be discussed in the Examples below, the detergent composition is highly effective in solubilizing, emulsifying and removing oily and greasy soils from fabric. The inventive alkoxylated amines and nonionic surfactants when combined within a specified weight ratio range unexpectedly and synergistically improve oily soil removal from fabrics.
Without wishing to be bound by any particular theory, the cleaning performance provided by the inventive detergent composition is believed to be a function of the two components of the proposed composition, namely the stable self-dispersing alkoxylated amine and the nonionic surfactant. The alkoxylated amines of the invention are notably dispersible in water and form stable hydrophobic aqueous dispersions. When the surface active alkoxylated amines described herein are combined with an optimum ratio (i.e., quantity) of a water soluble nonionic surfactant under typical laundry washing conditions, the result is the formation of a dynamic aqueous hydrophobic micellar detergent solution which enhances the removal and aqueous emulsification of hydrophobic oily soils from fabric. Most notably is the significant hydrophobic degreasing performance imparted as in the case of removal of motor oil from cotton polyester fabrics disclosed in the examples below.
In addition, the foam profile of the inventive method is suitable for use in automatic washing machines, including horizontal-axis washing machines now gaining favor due to their low water and energy usage. Since both groups of surfactants are generally recognized as moderate to low foaming compounds, it would be expected, and has been observed in the testing process, that the foam profile is moderate to low. Such a low to moderate foam profile is important for use of the detergent composition in an automatic washing machine and to avoid overflow of the foam from the washing machine.
As summarized above, the detergent composition comprises from about 10 to 50% by weight of a polyalkoxylated amine and from 90-50% by weight of a water-soluble nonionic surfactant. The polyalkoxylated amine has a general structural formula selected from the group consisting of: ##STR3## wherein R 1 is selected from an alkyl, aryl or alkylaryl group having between 6 and 22 carbon atoms, R 2 is from 0 to 7 moles of alkoxylated units, n is 0 or 1, R 3 and R 4 are each selected from H and from 1 to 15 moles of alkoxylated units such that R 3 and R 4 are not both H, and ##STR4## wherein R 5 is selected from an alkyl, aryl or alkylaryl group having between 6 and 22 carbon atoms, R 6 is from 0 to 7 moles of alkoxylated units, n is 0 or 1, R 7 , R 8 and R 9 are each selected from H and from 1 to 15 moles of alkoxylated units such that R 7 , R 8 and R 9 are not each H.
The alkoxylated units are preferably selected from the group consisting of ethyleneoxy, propyleneoxy, butyleneoxy and mixtures thereof. Preferably, R 3 and R 4 combined include from about 2 to 10 moles of alkoxylated units. Most preferably, R 3 and R 4 combined include from about 2 to 7 moles of alkoxylated units. R 7 , R 8 and R 9 combined preferably include from about 3 to 10 moles of alkoxylated units.
Tomah Products, Inc. of Milton, Wis. manufactures and sells polyalkoxylated amines useful in practicing the invention. Examples of suitable Tomah polyalkoxylated amines include E-17-5, E-14-2, E-DT-3 and P-DT-2.
A wide range of nonionic water-soluble surfactants are suitable for use in the invention. Such surfactants include alkoxylated alkyl phenols, alkoxylated alcohols, alkoxylated glycosides and mixtures thereof.
Preferred alkoxylated alkyl phenols include the polyethylene, polypropylene, and polybutylene oxide condensates of alkyl phenols. In general, the polyethylene oxide condensates are preferred. These compounds include the condensation products of alkyl phenols having an alkyl group containing from about 6 to about 12 carbon atoms in either a straight chain or branched chain configuration with the alkylene oxide. In a preferred embodiment, the ethylene oxide is present in an amount equal to from about 2 to about 25 moles of ethylene oxide per mole of alkyl phenol. Preferred alkoxylated alkyl phenols are nonylphenol 9 mole ethoxylate and octylphenol 9 mole ethoxylate. Commercially available nonionic surfactants of this type include Igepal™ CO-630, marketed by the Rhone-Poulenc; and Triton™ X-45, X114, X100 and X102, all marketed by the Union Carbide Corporation.
Useful alkoxylated alcohols include the alkyl ethoxylate condensation products of aliphatic alcohols with from about 1 to about 25 moles of ethylene oxide. The alkyl chain of the aliphatic alcohol can either be straight or branched, primary or secondary, and generally contains from 8 to 22 carbon atoms. Particularly preferred are the condensation products of alcohols having an alkyl group containing from 10 to 20 carbon atoms with from about 2 to about 10 moles of ethylene oxide per mole of alcohol. Most preferred are the condensation products of alcohols having an alkyl group containing from 10 to 14 carbon atoms with from about 6 to about 10 moles of ethylene oxide per mole of alcohol. Preferred alkoxylated alcohols include dodecyl alcohol 7 mole ethoxylate, tridecyl alcohol 7 mole ethoxylate, tetradecyl alcohol 7 mole ethoxylate, dodecyl/pentadecyl alcohol 7 mole ethoxylate blend and hexadecyl alcohol 7 mole ethoxylate.
Examples of commercially available nonionic surfactants of this type include Tergitol™ 15-S-9 (the condensation product of C11-C15 linear alcohol with 9 moles ethylene oxide), Tergitol™ 24-L-6 NMW (the condensation product of C12-C14 primary alcohol with 6 moles ethylene oxide with a narrow molecular weight distribution), both marketed by Union Carbide Corporation; Neodol™ 45-9 (the condensation product of C14-C15 linear alcohol with 9 moles of ethylene oxide), Neodol™ 25-9 (the condensation product of C12 - C15 linear alcohol with 9 moles of ethylene oxide), Neodol™ 23-6.5 (the condensation product of C12-C13 linear alcohol with 6.5 moles of ethylene oxide), Neodol™ 45-7 (the condensation product of C14-C15 linear alcohol with 7 moles of ethylene oxide), Neodol™ 45-4 (the condensation product of C14-C15 linear alcohol with 4 moles of ethylene oxide), marketed by Shell Chemical Company, and Kyro™ EOB (the condensation product of C13-C15 alcohol with 9 moles ethylene oxide), marketed by The Procter & Gamble Company.
Suitable alkoxylated glycosides include alkylpolysaccharides disclosed in U.S. Pat. No. 4,565,647 (Llenado) having a hydrophobic group containing from about 6 to about 30 carbon atoms, preferably from about 10 to about 16 carbon atoms and a polysaccharide, e.g., a polyglycoside, hydrophilic group containing from about 1.3 to about 10, preferably from about 1.3 to about 3, most preferably from about 1.3 to about 2.7 saccharide units. Any reducing saccharide containing 5 or 6 carbon atoms can be used, e.g., glucose, galactose and galactosyl moieties can be substituted for the glucosyl moieties. (Optionally, the hydrophobic group is attached at the 2-, 3-, 4-, etc. positions thus giving a glucose or galactose as opposed to a glucoside or galactoside.) The intersaccharide bonds can be, e.g., between the one position of the additional saccharide units and the 2-, 3-, 4-, and/or 6- positions on the preceding saccharide units.
The preferred alkylpolyglycosides have the formula:
R.sup.2 O (C.sub.n H.sub.2n O).sub.t (glycosyl).sub.x
wherein R 2 is selected from the group consisting of alkyl, alkylphenyl, hydroxylalkyl, hydroxyalkylphenyl, and mixtures thereof in which the alkyl groups contain from 10 to 18, preferably from 12 to 14, carbon atoms; n is 2 or 3, preferably 2; t is from 0 to about 10, preferably 0; and x is from about 1.3 to about 10, preferably from about 1.3 to about 3, most preferably from about 1.3 to about 3, most preferably from about 1.3 to about 2.7. The glycosyl is preferably derived from glucose. To prepare these compounds, the alcohol or alkylpolyethoxy alcohol is formed first and then reacted with glucose, or a source of glucose, to form the glucoside (attachment at the 1- position). The additional glycosyl units can then be attached between their 1- position and the preceding glycosyl units 2-, 3-, 4- and/or 6- position, preferably predominately the 2- position. Dodecylpolyglycoside is an illustrative preferred alkoxylated glycosides.
A representative commercially-available example of a C12 to C16 alkyl polyglycoside is GLUCOPON™ 600 which is an alkyl polyglycoside surfactant solution (50% active) which has an average degree of polymerization of 1.4 glucose units, a hydrophilic-lipophilic balance of 11.6 (calculated value) and in which the alkyl group contains 10 to 16 carbon atoms (average C12.8). A representative example of a C3 to C10 alkyl polyglycoside is GLUCOPON™ 225 which is an alkyl polyglycoside surfactant solution (65% active) which has an average degree of polymerization of 1.6 glucose units, a hydrophilic-lipophilic balance of 13.6 (calculated value) and in which the alkyl group contains 8 to 10 carbon atoms (average C9.1). Such surfactants are commercially available from Henkel Corporation, Ambler, Pa. 19002 and are described in U.S. Pat. No. 5,266,690.
Additionally, numerous other nonionic surfactants of the type referenced in this invention are known and suitable for use in the composition of the present invention. A variety of these can be found in McCutcheon's Emulsifiers and Detergents, 1997 and The Handbook of Industrial Surfactants, by Gower Publishing Company, 1997, and are herein incorporated by reference.
It is preferred that the polyalkoxylated amine consist of from about 20-50% by weight of the composition and that the nonionic surfactant consist of from about 80-50% by weight of the composition. Most preferably, the polyalkoxylated amine consists of from about 30-40% by weight of the composition and the nonionic surfactant consists of from about 70-60% by weight of the composition.
The method may include, at any time prior to the washing step, the further step of adding a further constituent to the composition to achieve a desired physical state and actives level. The further constituent is preferably selected from the group consisting of water, organic solvents, hydrotropes and mixtures thereof. It is acceptable to use mixtures of these constituents in order to achieve the desired homogeneous physical state of the detergent composition.
The detergent composition at any time prior to the washing step may be diluted to achieve a final percent actives of between about 99.99 and 0.001%. Water is the most preferred diluent.
It is anticipated that other typical laundry detergent constituents can be added to the detergent composition of the invention. By way of example only, such optional constituents include alkaline builders, hydrotropes, enzymes, enzyme stabilizing agents, soil suspension polymers, dyes, brighteners, perfumes, buffering agents, chelating agents, and suds control compounds. These additives are not required to practice the invention.
EXAMPLES AND DATA
The fabric cleaning test protocol for Examples 1-3 followed the American Society of Testing and Materials procedure Designation D-3050-87. The washing was performed in a standard tergotometer from U.S. Testing Co. The tergotometer included three wash-water vessels each having 1 l of detergent-containing wash water with the detergent level in each vessel adjusted to 0.1% actives. Each wash-water vessel included a motorized agitator. The wash water was at a temperature of 58° C. with a hardness of 150 ppm (3 Ca 2+ /2 Mg 2+ ion ratio).
The tergotometer also included three rinse-water vessels each containing 1 l of clean rinse water. The rinse water had a hardness of 150 ppm. Each rinse-water vessel included a motorized agitator.
Three fabric swatches were used for each test in the three examples below. The fabric swatches were supplied by Test Fabrics, Inc. and were pre-soiled with used motor oil. The fabric swatches were made of a 65/35% polyester cotton blend fabric and were 3"×4" in size.
The oil-soiled fabric swatches in each test were first examined with a spectrophotometer to establish a baseline light reflectance representing the soiled fabric. The swatches were then agitated in their respective wash-water vessels for 10 minutes at 125 rpm. In each test, foam formation was observed to be low to moderate.
Each swatch was then removed from the detergent-containing wash-water vessel and placed in separate rinse-water vessel. Each fabric swatch was agitated in the rinse water for 5 minutes at 125 rpm. The fabric swatches were then removed for drying.
The swatches were air dried overnight and reexamined with the spectrophotometer to determine the change in reflectance. The reflectance change represents the percent soil removed. The percent soil removed as determined by the spectrophotometer is recorded in the following Tables 1-8. All of the constituents reflected in the Examples are expressed in weight percent.
Example 1
Detergent Compositions with Different Component Ratios
Detergent compositions consisting of a blend of two main components were prepared. In the compositions shown in Table 1, the first component was the nonionic surfactant nonylphenol 9 mole ethoxylate ("NP-9EO") sold by Union Carbide under the name Tergitol® NP-9 and the second component was a polyalkoxylated amine consisting of polyethoxylated (2) isodecyloxypropylamine prepared and sold by Tomah Products as E-14-2. Table 2 shows a two component composition including the NP-9EO surfactant and polyethoxylated (5) isotridecyloxypropyl amine sold by Tomah Products as E-17-5.
In the compositions of Table 3, the first component was the nonionic surfactant C12-15 AE-7EO, an alcohol ethoxylate having 7-moles of ethylene oxide sold by Shell Chemical Company under the name Neodol 25-7 while the second component was Tomah Products E-14-2. The compositions in Table 4 consisted of a first component which was a C12-16 alkyl polyglycoside sold by Henkel Corporation as Glucopon 600 blended with Tomah Products E-14-2.
The tests of this example were conducted as set forth above. Following washing, the swatches were analyzed to determine the percent soil removed and to determine the optimal component ratio. The data are presented in Tables 1-4 below.
TABLE 1______________________________________Exemplary Detergent Constituents at Optimal RatiosTest Weight % Active Amine of Total Surfactant %-SoilNumber Constituents Removal______________________________________1 0.0% (NP-9EO only) 19.82 1.0 17.73 2.5 18.34 5.0 20.45 10.0 23.56 20.0 31.87 30.0 54.98 40.0 41.99 50.0 15.110 100.0 (E-14-2 only) -14.1______________________________________
TABLE 2______________________________________Other Exemplary Detergent Constituents at Optimal RatiosTest Weight % Actives Amine of Total Surfactant %-soilNumber Constituents removal______________________________________1 0.0% (NP-9EO only) 19.802 5.0 22.503 10.0 26.104 20.0 30.605 30.0 37.906 40.0 39.607 50.0 48.408 100.0 E-17-5 5.40______________________________________
Example 1, Tables 1 and 2 demonstrates that an exemplar detergent composition of the invention which includes a nonionic surfactant (NP-9EO) and a stable self-dispersing alkoxylated amine (Tomah E-14-2 or E-17-5) are effective in removal of hydrocarbon-containing motor oil. The data further show that the effectiveness of the exemplary detergent composition varies depending on the component ratio. As shown in test number 7 of Table 1, an exemplary detergent composition with a ratio of 70% nonionic surfactant and 30% polyalkoxylated amine is most effective at removing the motor oil for the surfactant pair including NP-9EO and Tomah E-14-2. Table 2, test number 7 shows that the synergistic combination of NP-9EO and Tomah E-17-5 is most effective at a ratio of 50% nonionic surfactant and 50% amine.
TABLE 3______________________________________Other Exemplary Detergent Constituents at Optimal RatiosTest Weight % Actives Amine of Total Surfactant %-soilNumber Constituents removal______________________________________1 0.0% (C1215 AE-7EO only) 17.762 5.0 18.783 10.0 22.734 20.0 31.205 30.0 47.736 40.0 25.707 50.0 12.828 100.0 E-14-2 -15.21______________________________________
Example 1, Table 3 shows the efficacy of an ethoxylated alcohol/alkoxylated amine composition in removing motor from fabric. The optimal component ratio in this example is 60% nonionic surfactant and 40% amine.
TABLE 4______________________________________Other Exemplary Detergent Constituents at Optimal RatiosTest Weight % Actives Amine of Total Surfactant %-soilNumber Constituents removal______________________________________1 0.0% (C1216 Glycoside only) 2.572 10.0 15.823 20.0 17.174 30.0 29.315 40.0 43.096 50.0 24.707 60.0 5.688 100.0 E-14-2 -15.21______________________________________
Example 1, Table 4 shows that a composition of the Glucopon 600 and Tomah E-14-2 are effective in removing motor oil from fabric. In this data set, the optimal component ratio is 60% nonionic surfactant and 40% amine.
Example 2
Comparison of Performance of Detergent Compositions with Different Constituents and Constituent Ratios
Exemplary detergent compositions were again prepared. As set forth in Table 5 below, tests 1-9 were conducted with detergent compositions consisting of either a nonionic surfactant or a polyalkoxylated amine. Tables 6-8 show that tests 7-22 were conducted with exemplary detergent compositions having varying alkoxylated amine blends and the nonionic surfactants NP-9EO, Neodol 25-7 and Glucopon 600 respectively.
The 22 tests of Example 2 were performed using the same protocol as the tests of Example 1 above. The tests were repeated with the varying ratios of the nonionic surfactant and alkoxylated amine as set forth in the tables and the swatches were then analyzed to determine the percent soil removed. The data are presented in Tables 5-8 below.
TABLE 5______________________________________Performance of Neat AlkoxylatedAmine or Nonionic SurfactantsTest %-SoilNumber Surfactant Removal______________________________________1 Polyethoxylated (3) isotridecyloxypropyl,1,3 0.69 diaminopropane2 Polyethoxylated (5) isotridecyloxypropylamine 26.823 Polyethoxylated (10) isotridecyloxypropylamine 25.794 Polyethoxylated (2) coco amine -20.545 Polyethoxylated (5) coco amine 24.026 Nonylphenol 9 mole ethoxylate 23.447 Polyethoxylated (5) tallow amine 6.578 C1215 AE-7EO 17.769 C1216 Glycoside 2.57______________________________________
TABLE 6______________________________________Performance of Blended Exemplary Nonionic/AlkoxylatedAmine SurfactantsTest Nonylphenol 9 Mole Ethoxylate/ %-SoilNumber Alkoxylated Amine Blends Removal______________________________________10 Polyethoxylated (5) isotridecyloxypropylamine 28.77 (70/30 nonionic/amine ratio)11 Polyethoxylated (5) isotridecyloxypropylamine 30.85 (60/40 nonionic/amine ratio)12 Polyethoxylated (10) isotridecyloxypropylamine 35.52 (60/40 nonionic/amine ratio)13 Polyethoxylated (3) isotridecyloxypropyl,1,3 34.33 diaminopropane (70/30 nonionic/amine ratio)14 Polyethoxylated (2) coco amine 38.05 (70/30 nonionic/amine ratio)15 Polyethoxylated (2) coco amine 18.03 (60/40 nonionic/amine ratio)16 Polyethoxylated (5) coco amine 27.34 (60/40 nonionic/amine ratio)______________________________________
TABLE 7______________________________________Performance of Blended Exemplary Ethoxylated Alcohol/Alkoxylated Amine SurfactantsTest % SoilNumber C1215 AE-7EO/Alkoxylated Amine Blends Removal______________________________________17 Polyethoxylated (2) coco amine 44.01 (70/30 nonionic/amine ratio)18 Polyethoxylated (3) isotridecyloxypropyl-1,3- 40.62 diaminopropane (60/40 nonionic/amine ratio)19 Polyethoxylated (5) tallow amine (70/30 27.63 nonionic/amine ratio)______________________________________
TABLE 8______________________________________Performance of Blended Exemplary Alkyl Glycoside/Alkoxylated Amine SurfactantsTest % SoilNumber C1216 Glycoside/Alkoxylated Amine Blends Removal______________________________________20 Polyethoxylated (2) coco amine 9.65 (60/40 nonionic/amine ratio)21 Polyethoxylated (3) isotridecyloxypropyl-1,3- 10.70 diaminopropane (60/40 nonionic/amine ratio)22 Polyethoxylated (5) tallow amine 17.04 (60/40 nonionic/amine ratio)______________________________________
Example 2, Tables 5-8 demonstrates that the performance of the exemplary detergent compositions and the optimal component ratio varies depending on the nonionic surfactant and the alkoxylated amine used to prepare the detergent composition. The data also show that the exemplary surfactants consisting of a blend of nonionic and alkoxylated amine surfactants generally outperform detergent compositions consisting of only a nonionic surfactant or alkoxylated amine surfactant. For example, the percent soil removal of the blended nonionic/amine compositions in test numbers 20-22 of Table 8 is significantly better than the soil removal of the 100% active glycoside in test 9 of Table 5.
Example 3
Performance of Detergent Formulations of the Invention Including Typical Laundry Detergent Additives
It is well known that optional components are included in laundry detergents to broaden the cleaning profile. These additives may include builders and other components such as adjuvants. It is intended that such additives may be included in the method of the present invention. The tests of Example 3 were undertaken to determine the effect of such additives, if any, on soil removal by the detergent compositions of the invention. The tests of Example 3 were performed using the protocols as in Examples 1 and 2 but using the six detergent composition formulations, including additives, set forth in Table 9 below. In each case motor oil-soiled polyester/cotton fabric swatches were washed in detergent-containing wash water adjusted to 0.1% detergent actives. The percent soil removal was observed and the data are set forth in Table 4 below.
TABLE 9______________________________________Performance of Detergent CompositionsIncluding Typical AdditivesFormu-lations (F) F1 F2 F3 F4 F5 F6______________________________________Nonylphenol 10 g 7 g 10 g 7 g 10 g 7 g9 moleethoxylatePolyethoxy- 3 g 3 g 3 glated (2) iso-decyloxy-propyl-amineSodium meta- 5 g 5 gsilicatepentahydrateSodium hy-droxide (50%) 5 g 5 gTriethanol 10 g 10 gamineWater/inerts balance balance balance balance balance balance% Soil 16.8 56.9 19.3 43.5 12.2 15.3Removed______________________________________
Example 3 demonstrates that standard alkaline builders may have a negative effect on the degreasing synergy of an exemplary nonionic/alkoxylated amine surfactant composition. The tergotometer data show that the presence of alkaline builders in Formulation 6 decreases the percent oil removal versus Formulation 2 in which no builders are present. However, the presence of the builder triethanol amine in Formulation 4 only slightly reduces the oil-removal ability of the detergent composition. These data suggest that inclusion of additives, such as builders, are consistent with the present invention in that they may expand the range of other types of stains (such as dust sebum, carbon, etc.) which can be removed without significant loss of ability to remove oily and greasy substances. The compatibility of the detergent of the inventive method with other components broadens the potential applications for the invention.
While the principles of this invention have been described in connection with specific embodiments, it should be understood clearly that these descriptions are made only by way of example and are not intended to limit the scope of the invention.
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This invention is directed to an improved method for removing hydrocarbon-containing greases and oils from fabrics. The invention consists of preparing a detergent composition and washing the fabric to be cleaned with the detergent composition. Broadly, the detergent composition consists of from about 10-50% by weight of a polyalkoxylated amine and from about 90-50% by weight of a water-soluble nonionic surfactant. The invention has desirable foamability characteristics.
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RELATIONSHIP TO PRIOR APPLICATION
This is a continuation of application Ser. No. 714,696 filed Aug. 16, 1976, now abandoned, which in turn was a division of application Ser. No. 596,571 filed July 16, 1975, now U.S. Pat. No. 3,978,216, which in turn was a continuation-in-part of application Ser. No. 475,856, filed Apr. 23, 1974, now U.S. Pat. No. 3,947,579.
BACKGROUND OF THE INVENTION
Background of the Prior Art
U.S. Pat. No. 3,471,548 describes compounds having the structural formula ##STR1## wherein R is chloro, bromo, fluoro or fluoromethyl. The compounds are known to cross the blood brain barrier and are known to have muscle relaxant properties and to be useful in the treatment in man of spasticity of spinal origin.
Neuroleptic drugs are used to treat schizophrenia. Examples of common neuroleptic drugs include phenothiazines such as chloropromazine; butyropnenones such as haloperidol and others such as pimocide and clozapine. Side effects of neuroleptic drugs include sedation and tardive dyskinesias. The latter side effect is particularly important because it results in involuntary muscle movements especially of the face and mouth which become irreversible. The onset of this side effect is directly related to the amounts of and length of time which a neuroleptic drug is used in treatment.
SUMMARY OF THE INVENTION
There has now been discovered a method for treating schizophrenia and a method and composition for potentiating the beneficial effects and for reducing the side effects of neuroleptic drugs.
The foregoing results are obtained by administering to a schizophrenic an effective amount of a gabergic compound or by coadministering to a schizophrenic a neuroleptic drug and a potentiating amount of a gabergic compound such as γ-hydroxybutyrolactone, γ-hydroxybutyrate, aminooxyacetic acid, 5-ethyl-5-phenyl-2-pyrrolidone, 1-hydroxy-3-amino-2-pyrrolidone, or a compound having the structural formula ##STR2## wherein R is a halogen or trifluoromethyl and salts thereof.
The present invention further relates to a composition comprising a neuroleptic drug and a potentiating amount of a gaberic compound together with a suitable pharmaceutical carrier.
DETAILED DESCRIPTION OF THE INVENTION
Compounds having the foregoing structural formula such as, for example, β-(4-chlorophenyl)-γ-aminobutyric acid and pharmaceutically acceptable salts thereof and pharmaceutical compositions thereof and their manner of making is described in U.S. Pat. No. 3,471,548 and relevant portions thereof are hereby incorporated by this reference. γ-hydroxybutyrolactone, γ-hydroxybutyrate and aminooxyacetic acid, 5-ethyl-5-phenyl-2-pyrrolidone, 1-hydroxy-3-amino-2-pyrrolidone are also known to those of skill in the art.
The amount of GABA-like or gabergic compound which may be used in the present invention ranges from about 0.1 to about 100 mg/kg and preferably from about 0.1 to about 10 mg/kg and preferably about 0.1 to 1.5 mg/kg per day.
The term "gabergic" compound herein refers to compounds which are related pharmacologically to γ-aminobutyric acid, known as GABA. Typical examples of GABA-like or gabergic compound include γ-hydroxybutyrolactone, γ-hydroxybutyrate, aminooxyacetic acid, 5-ethyl-5-phenyl-2-pyrrolidone, 1-hydroxy-3-amino-2-pyrrolidone, and β-(4-chlorophenyl)-γ-aminobutyric acid. When used herein, the term "gabergic compound" refers to any gabergic compound, such as, but not limited to, the foregoing gabergic compounds.
Neuroleptic drugs which may be used in the present invention include phenothiazine derivatives such as chloropromazine, promozine, triflupromozine, acetophenazine, butaperozine, corphenazine, fluphenazine, perphenazine, prochlorperozine, thiopropazate, trifluoperazine, mepazine, mesoridazine, piperacetozine, theoridazine, chlorprothizine, thiothixine, benzoctamine, cidorepin, clomacran, clopenthixol, clothiapine, clothixamide, clozapine, dimeprozan, doxepin, lovapine, perlapine and pinovepin; rauwolfia derivatives including deserpidine, metaserpate, rescinnamine, reserpine, bezquinamide, oxypertine, tetrabenazine, indopine, indriline, methopholine, milipertine, molindone, solypertine, yohimbine and solertine; diphenylmethane derivatives including benactyzine, piperilate, azacyclonal, captodiamine, hydroxyzine, cyprolidol, hexandrol and pimizide; and butyrophenone derivatives including haloanisone, haloperidol, ozaperone, benperidal, carperone, droperidal, fluspirilene, meperone, penfluridol, pipamperone, seperidol, spiperone and trifluperidol. When used herein, the term "neuroleptic drugs" refers to any neuroleptic drug such as, but not limited to, the foregoing neuroleptic drugs.
While Applicant does not necessarily rely on the following theory of action as to why the gabergic compounds are useful in the treatment of schizophrenia and to potentiate the effects of neuroleptic drugs, Applicant believes that known neuroleptic drugs act by blocking dopamine receptor activity in the brain. However, whenever the dopamine receptor activity is blocked, compensatory mechanisms are initiated by the central nervous systems to restore normal dopamine receptor activity. The compensatory mechanisms act by blocking the normal inhibitory γ-aminobutyric acid (GABA) activity of dopamine cell bodies, thus tending to increase dopamine neuron activity. Applicant believes the gabergic compounds selectively interfere with the compensatory mechanisms controlling activity in the mesolimbic dopamine neurons by increasing GABA receptor activity in the medial dopamine cell bodies of the midbrain, which innervate the limbic forebrain and thereby potentiate the effect of neuroleptic drugs by blocking the the increase of limbic dopamine turnover otherwise caused by the neuroleptic drum. In this manner, the gabergic compound can be used to potentiate the beneficial effects of neuroleptic drugs, since their antipsychotic effect is believed to be due to blockade of limbic dopamine receptors and themselves have therapeutic benefit in the treatment of schizophrenia. Applicant further believes that extrapyramidal side effects, e.g., tardive dyskinesia and parkinsonian-like side effects, are mediated through the blockade of neostriatal dopamine receptors. Thus, when coadministered with the foregoing neuroleptic drugs, the gabergic compounds described herein allow the use of lower doses of neuroleptic drugs to obtain the same antipsychotic effect as obtained with higher doses of neuroleptic drug without the gabergic compounds. At the same time, neostriatal dopamine receptor blockade is reduced and thus extrapyramidal side effects are likewise reduced or eliminated. As a result of the foregoing, the dose of neuroleptics now given may be decreased by a factor of 2-20 times (about 5-50% of usual dose) when co-administered with an effective amount of one of the gabergic compounds of the present invention.
For purposes of this invention, the term "co-administered" means the administration of a neuroleptic drug and a gabergic compound as described herein to a patient during a course of treatment.
For purposes of this disclosure, the phrase "treatment of schizophrenia" means the temporary alleviation of at least some of the signs or symptoms of schizophrenia.
The pharmaceutical compositions may be in a form suitable for oral use, for example, as tablets, aqueous or oily suspensions, dispersible powders or granules, emulsions, hard or soft capsules, or syrups or elixirs. Compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from the group consisting of sweetening agents, flavoring agents, coloring agents and preserving agents in order to provide a pharmaceutically elegant and palatable preparation. Tablets contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for manufacture of tablets. These excipients may be, for example, inert diluents, for example calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, maize starch, or aliginic acid; binding agents, for example starch, gelatine or acacia, and lubricating agents, for example magnesium stearate or stearic acid. The tablets may be uncoated or they may be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period.
Formulations for oral use may also be presented as hard gelatine capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatine capsules wherein the active ingredient is mixed with an oil medium, for example, arachis oil, liquid paraffin or olive oil.
Aqueous suspensions contain the active ingredients in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example, sodium carboxymethyl cellulose, methylcellulose, hydroxypropylmethylcellulose, sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia; dispersing or wetting agents may be a naturally-occurring phosphatide, for example lecithin, or condensation products of an alkylene oxide with fatty acids, for example, polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example, heptadecaethyleneoxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol, for example polyoxyethylene sorbitol monooleate, or condensation product of ethylene oxide with partial esters derived from fatty acids and hexitol anhydrides, for example polyoxyethylene sorbitan monooleate. The said aqueous suspensions may also contain or more preservatives, for example, ethyl, or n-propyl, p-hydroxy benzoate, one or more coloring agents, one or more flavoring agents and one of more sweetening agents, such as sucrose, saccharin, or sodium or calcium cyclamate.
Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent an one or more preservatives. Suitable dispersing or wetting agents and suspending agents are exemplified by those already mentioned above. Additional excipients, for example, sweetening, flavoring and coloring agents, may also be present.
Syrups and elixirs may be formulated with sweetening agents, for example, glycerol, sorbitol or sucrose. Such formulations may also contain a demulcent, a preservative and flavoring and coloring agents. The pharmaceutical compositions may be in the form of a sterile, injectable preparation, for example as a sterile, injectable aqueous suspension. This suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent, for example, as a solution in 1,3-butane diol.
The pharmaceutical compositions may be tableted or otherwise formulated so that for every 100 parts by weight of the composition there are present between 5 and 95 parts by weight of the active ingredients and preferably between 25 and 85 parts by weight of the active ingredients. The dosage unit form will generally contain between about 10 mg and about 500 mg of the active ingredients. A preferred dosage rate for oral administration is of the order of 1-1000 mg daily, optionally in divided doses.
From this foregoing formulation discussion, it is apparent that the compositions of this invention can be administered orally or parenterally. The term "parenteral" as used herein includes subcutaneous injection, intravenous, intramuscular, or intrasternal injection or infusion techniques.
This invention is further demonstrated by the following examples in which all parts are by weight.
EXAMPLE I
The effect of β-(4-chlorophenyl)-γ-aminobutyric acid Lioresal) on the pimozide-induced increase in dopamine fluorescence disappearance from the neostriatum and subcortical limbic areas of rats after treatment with α-methyltyrosine methyl ester
Dopamine neuron nerve endings can be made to fluoresce strongly as a result of the presence of stored dopamine. These stores of dopamine are not static; there is a continual release, reuptake, degradation and de novo synthesis at the nerve ending.
α-methyltyrosine methyl ester is an inhibitor of dopamine synthesis. Fluorescence microscopy shows that α-methyltyrosine methyl ester depletes dopamine stores. Therefore, α-methyltyrosine methyl ester may be used to determine dopamine turnover in the nerve endings since turnover is directly proportional to the rate of dopamine depletion.
When dopamine receptors are blocked by drugs such as pimozide and haloperidol, the dynamic state of dopamine at and in the nerve endings increase. This appears as an increased disappearance of fluorescence after administration of α-methyltyrosine methyl ester. This increase results from a compensatory response to the decreased stimulation of the nerve cells normally receiving the dopamine stimulation.
α-methyltyrosine methyl ester (H 44/63), an inhibitor of dopamine synthesis, was given to male Sprague-Dawley rats i.p. in a dose of 250 mg/kg 4 hrs before killing. β-(4-chlorophenyl)-γ-aminobutyric acid (Lioresal) was given i.p. in a dose of 10, 20 or 25 mg/kg 15 minutes before H 44/68. Pimozide was given i.p. in a dose of 1 mg/kg 2 hours before H 44/68, and haloperidol in a dose of 5 mg/kg 1 hour before H 44/68. The dopamine levels were determined by measuring histochemical fluorescence. The fluorescence intensity reflects the amount of dopamine present. The fluorescence intensity was semi-quantitatively estimated on coded slides. 3 = strong; 2 = moderate; 1 = weak; 1/2 = very weak. Number of animals is shown within parenthesis. Table 1 below tabulates the data obtained.
Table 1__________________________________________________________________________ Fluorescence intensityTreatment Neostriatum Limbic forebrain__________________________________________________________________________No drug treatment 3 (4) 3 (4)H44/68 0.5(1) 1(2) 1.5(2) 0.5(2) 1(2) 1.5(1)Pimozide + H44/68 0(7) 0.5(1) 0 (7) 0.5(5).sup.dPimozide + Lioresal 0(2) 0.5(4) 1.5(2) 2(2) 1.5(4) 2(6).sup.e(20) + H44/68Pimozide + Lioresal 0(3) 0.5(3) 1 (2) 1.5(3) 1(1) 1.5(6) 2(4).sup.f(10) + H44/68Haloperidol + H44/68 0.5(1) 1(6) 0.5(2) 1(6).sup.gHaloperidol + Lioresal 1(4) 1.5(2) 2(1) 2(6) 2.5(2).sup.h(10) + H44/68Lioresal (25) + H44/68 1(1) 1.5(3) 1(1) 1.5(1) 2(2)Lioresal (10) + H44/68 1.5(2) 2(1) 1.5(1) 2(1) 2.5(1)__________________________________________________________________________ Statistical significance according to Tukey's Quick test: .sup.d-e p < 0.001 .sup.d-f p < 0.001 .sup.g-h p < 0.001
The foregoing Example I shows that the dopamine turnover at the nerve endings is increased by pimozide and haloperidol. This increase is antagonized by β-(4-chlorophenyl)-γ-aminobutyric acid in the limbic forbrain (nuc. accumbens, tuberculum olfactorium). Thus, as seen from the foregoing table, the increased disappearance (i.e. decrease in amount) of dopamine fluorescence from the limbic forebrain but not from the neostriatum seen after introduction of pimozide and haloperidol is significantly counteracted by pre-treatment with β-(4-chlorophenyl)-γ-aminobutyric acid.
It can thus also be stated that Lioresal can counteract the pimozide increase in dopamine turnover also in the limbic cortex. This is important, since thought processes are usually linked to cortical regions and therefore these limbic dopamine receptors may be particularly involved in the control of the abnormal thought processes found in schizophrenia.
EXAMPLE II
Effect of γ-OH-butyrolactone on the pimozide-induced increase in DA fluorescence disappearance found after treatment with α-methyl tyrosine methyl ester in rats (6-9)
The method used in Example I was followed. Pimozide was given i.p. in a dose of 1 mg/kg 2 hrs before α-methyl tyrosine methyl ester (H44/68) (250 mg/kg, i.p., 2 hr). γ-OH-Butyrolactone was given i.p. 15 min. before H44/68 in a dose of 300 mg/kg. The results of the study showed that γ-hydroxybutyrolactone selectively counteracted the pimozide-induced increases in dopamine turnover in the limbic system.
Thus, the foregoing Example II shows that γ-hydroxybutyrolactone also potentiates the antipsychotic action of neuroleptic drugs and at the same time reduces extrapyramidal-like side effects of neuroleptic drugs by enabling a lowering of the dosage of the neuroleptic given. The study also showed that γ-hydroxybutyrolactone would also be useful along in the treatment of schizophrenia.
EXAMPLE III
Effect of Lioresal and aminooxyacetic acid (AOAA) on the pimozide-induced increase in dopamine fluorescence disappearance found after treatment with α-methyl tyrosine methyl ester in rats (9-10)
The method of Example I was followed, pimozide (1 mg/kg i.p. was given 2 hrs before α-methyl tyrosine methyl ester (250 mg/kg, i.p. 2 hr before filling). Lioresal (5 mg/kg, i.p.) was given 15 min. before α-methyl tyrosine methyl ester, as was aminooxyacetic acid (25 mg/kg, i.p.).
The results of the study showed that aminooxyacetic acid selectively counteracted the pimozide-induced increase in dopamine turnover in the limbic system (nuc. accumbens, tuberculum olfactorium)
Thus, the foregoing example III also shows that aminooxyacetic acid potentiates the antipsychotic action of neuroleptic drugs and at the same time lowers extrapyramidal side effects by enabling a lowering of the dosage of the neuroleptic given. The study also shows that aminooxyacetic acid would also be useful alone in the treatment of schizophrenia.
EXAMPLE IV
Effect of 5-ethyl-5-phenyl-pyrrolidone (EPP) on the α-methyl tyrosine methyl ester induced dopamine fluorescence disappearance in the nuc. caudatus, nuc. accumbens and tuberculum olfactorium of rats
The method of Example I was followed. EPP was given i.p. in a dose of 50 mg/kg 15 min. before α-methyl tyrosine methyl ester (H44/68) (250 mg/kg, i.p. 2 hr before killing). The specific DA fluorescense is given in arbitrary fluorescence units. A Leitz microspectrofluorometer was used. The number of animals used is shown within parenthesis. The data is reported as a mean ± s.e.m. in Table 2 below.
Table 2__________________________________________________________________________Dopamine fluorescence Tuberculum nuc. huc.Treatment olfactorium % accumbens % caudatus %__________________________________________________________________________No drug treatment 30.9 ± 1.8 100 52.3 ±4.9 100 25.3 ±1.3 100 (3) (3) (3)H44/68 18.1 ± 1.5 58 29.8 ±1.4 57 13.7 ± 0.8 54 (5) (5) (5)EPP (50) + 28.7 ± 1.6 93 37.1 ± 1.2 71 14.4 ± 1.3 57H44/68 (4) (5) (5)__________________________________________________________________________
EXAMPLE V
The effect of Lioresal, aminooxyacetic acid (AOAA) and 5-ethyl-5-phenyl-2-pyrrolidone (EPP) on the pimozide induced increase of dopamine turnover in the dopamine terminal island of the entorhinal cortex
The method used in Example I was followed. Lioresal (10 mg/kg, i.p.), EPP (200 mg/kg, i.p.) and AOAA (25 mg/kg, i.p.) were administered 15 min. and 2 hr. (AOAA) before the α-methyl tyrosine methyl ester (H44/68) injection (250 mg/kg, i.p. 1 hr before killing). Pimozide (1 mg/kg) was given i.p. 2 hrs before the H44/68 injection.
The results of this study indicated that both EPP and AOAA, like Lioresal, counteracted the pimozide-induced increase in dopamine turnover in the entorhinal cortex. These results indicated that AOAA and EPP can selectively counteract the pimozide-induced increase in dopamine turnover in the limbic system including the important limbic cortical region.
Thus, the foregoing study shows that gabergic drugs of the EPP type also can potentiate the antipsychotic action of neuroleptic drugs, and also be active as such in schizophrenia. At the same time, extrapyramidal side effects of neuroleptic drugs are reduced by gabergic drugs since they enable a lowering of dosage of the neuroleptic drug given.
EXAMPLE VI
Tablets, each containing 60 mg of the active combination can be prepared, for example, from the following ingredients:
______________________________________ Mg.______________________________________β-(4-chlorophenyl)-γ-aminobutyric 40Lactose 95Wheat starch 54Gelatine 6Arrowroot 24Stearic acid 6Talcum 15Chloropromazine 10______________________________________
Preparation of the Tablets
The active ingredients are homogeneously mixed with lactose and wheat starch and pressed through a 0.5 mm mesh sieve. Gelatine is dissolved in 10 times its own weight of water; the powder mixture is evenly moistened with this solution and kneaded until a plastic mass has formed which is then pressed through a 3 mm mesh sieve, dried at 45° C. and then sifted through a 1.5 mm mesh sieve. Arrowroot, stearic acid and talcum are finely sifted and worked into the resulting mixture, and the paste is then made up in the usual manner into tablets of 9 mm diameter and 250 mg weight.
EXAMPLE VII
Example VI is repeated, except a number of tablet formulations were prepared using one of the following compounds in the place of β-(4-chlorophenyl)-γ-aminobutyric acid: γ-hydroxybutyrolactone, γ-hydroxybutyrate, aminooxyacetic acid, 5-ethyl-5-phenyl-2-pyrrolidone and 1-hydroxy-3-amino-2-pyrrolidone; and one of the following neuroleptic compounds in the place of chlorpromaxine: fluphenazine, clozapine, resperpine and haloperidol.
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A method for treating schizophrenia and a method and composition for potentiating the beneficial effects and reducing the side effects of neuroleptic drugs. Schizophrenia is treated with a GABA-like compound such as Lioresal. Neuroleptic drugs are potentiated by coadministering to a schizophrenic a neuroleptic drug and a GABA-like drug such as Lioresal.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit under Title 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 60/884,269, entitled PASSIVE HEATER, filed on Jan. 10, 2007, the entire disclosure of which is expressly incorporated by reference herein.
BACKGROUND
1. Field of the Invention
The present invention relates to a passive heater, particularly to a passive heater for use in conjunction with a cooking surface.
2. Description of the Related Art
Numerous devices having heated cooking surfaces are utilized in the food service industry. These devices may be formed as griddles or stoves, for example, having heated cooktops upon which food to be cooked is placed. These devices transfer thermal energy from the cooktop to the bottom of the food thereon. Once the bottom surface of the food is sufficiently cooked, the food may be flipped or otherwise repositioned so that different surfaces of the food are in direct contact with the cooktop. During cooking, it may be desirable to keep the top surface, i.e., the surface not in contact with the cooktop, of the food warm. Similarly, cheese or other condiments which need to be heated may be added to the top surface of a hamburger, for example.
SUMMARY
The present invention relates to a passive heater, particularly to a passive heater for use in conjunction with a cooking surface. In one exemplary embodiment, the passive heater includes a carriage actuatable to move along a cooking surface and a cover. In one exemplary embodiment, the carriage may be positioned on a guide bar to direct movement of the carriage along the cooking surface. The cover may be connected to the carriage and may be positionable near the cooking surface. Advantageously, positioning the cover near the cooking surface provides for the retention of nearby heat. Thus, the top surface of a food item cooking on the cooking surface may be heated by placing the cover over the food item. In another exemplary embodiment, the cover has a lifted position and a lowered position. By moving the cover from the lifted position to the lowered position, the cover may contact the cooking surface to surround food cooking thereon. Advantageously, by positioning the cover to surround uncooked food, contact between the uncooked food and any other food on the cooking surface is substantially prevented. In another exemplary embodiment, the lowered position of the cover may space the cover upwardly from the cooking surface, allowing the cover to cap food thereon.
Advantageously, the present passive heater provides for the heating of a food item on a cooking surface, without the need to create thermal energy in addition to the thermal energy created by the cooking surface. This allows the passive heater to function without components, such as active radiant, conductive, or convective heating elements, which require additional energy inputs. As a result, use of the passive heater may decrease operating costs. Further, the lack of sensitive components, such as electrical connections, makes the passive heater easier to clean, reducing labor costs. Additionally, the use of the present passive heater allows for the retention of moisture around the food cooking on the cooking surface. This helps to prevent the food from drying out during cooking.
In one form thereof, the present invention provides a passive heater including a carriage actuatable to move along a cooking surface, and a cover connected to the carriage, whereby actuation of the carriage moves the cover along the cooking surface, the cover positionable to contact the cooking surface, whereby heat is retained between the cover and the cooking surface.
In another form thereof, the present invention provides a passive heater including a carriage positioned adjacent a cooking surface, wherein the carriage may be actuated to move along the cooking surface, and a cover having a lifted position and a lowered position, the cover capable of being moved from the lifted position to the lowered position to cap food on the cooking surface.
In another form thereof, the present invention provides a method of heating food on a cooking surface including the steps of actuating a passive heater having a carriage and a cover to position the cover over food on the cooking surface, and lowering the cover toward the cooking surface to at least partially cap the food while maintaining the position of the carriage.
BRIEF DESCRIPTION OF THE DRAWINGS
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a perspective view of the passive heater of the present invention adjacent a cooking surface;
FIG. 2 is a partial perspective view of the passive heater and cooking surface of FIG. 1 ;
FIG. 3 is a partial cross sectional view of the passive heater and cooking surface of FIG. 1 , taken alone line 3 - 3 of FIG. 1 ;
FIG. 4 is a partial cross sectional view of the passive heater and cooking surface of FIG. 1 , taken along line 4 - 4 of FIG. 2 ;
FIG. 5 is an exploded view of the passive heater of FIG. 1 ; and
FIG. 6 is an assembly view of another embodiment of the passive heater of FIG. 1 .
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
DETAILED DESCRIPTION
Referring to FIG. 1 , passive heater 10 is shown positioned adjacent cooking surface 12 of griddle 14 . While passive heater 10 is described and depicted herein with specific reference to cooking surface 12 of griddle 14 , passive heater 10 may be utilized with any device having a cooking surface, such as a halogen cook top or a charbroiler. Additionally, as stated above, the device of the present invention is a passive heater. Passive heaters lack a heating element which generates thermal energy, such as an active radiant heating element. In a passive heater, the system only controls or directs thermal energy in a useful way. In contrast, in an active heater, a component of the system generates thermal energy and the system utilizes the thermal energy so generated in performing its intended function.
Passive heater 10 includes carriage 16 and cover 18 , as best seen in FIG. 5 . Carriage 16 may be actuated to move cover 18 over cooking surface 12 . As shown in FIG. 5 , carriage 16 includes first end 20 and second end 22 . First end 20 and second end 22 are connected via rails 24 positioned therebetween. As shown in FIGS. 1-6 , carriage 16 further includes top surface 26 connected between rails 24 and first and second ends 20 , 22 . As shown in FIG. 5 , rails 24 of carriage 16 include apertures 28 formed therein. In one exemplary embodiment, carriage 16 lacks top surface 26 . In this embodiment, at least a portion of cover 18 of passive heater 10 may be viewed from directly above passive heater 10 .
As shown in FIGS. 3-5 , cover 18 includes top surface 19 and downwardly extending sides 30 having bottom surfaces 32 . Sides 30 of cover 18 further include apertures 34 formed therein. Apertures 34 of cover 18 and apertures 28 of carriage 16 are sized to receive pins 36 of connecting arms 38 . Connecting arms 38 provide the connection between carriage 16 and cover 18 , and also facilitate movement of cover 18 relative to carriage 16 . In one embodiment, connecting arms 38 includes opposing pairs of resiliently deformable legs. As shown in FIG. 5 , connecting arms 38 include a pair of lower legs 40 and a pair of upper legs 42 .
To attach cover 18 to connecting arms 38 , lower legs 40 of connecting arms 38 are expanded, i.e., pulled apart from one another, and pins 36 of lower legs 40 are positioned within apertures 34 of sides 30 of cover 18 . Similarly, to attach connecting arms 38 to carriage 16 , upper legs 42 are contracted, i.e., pressed together, and pins 36 of upper legs 42 are positioned within apertures 28 of rails 24 of carriage 16 . As described in detail above, lower legs 40 and upper legs 42 are attached to cover 18 and carriage 16 , respectively, via pins 36 . However, lower legs 40 and upper legs 42 of connecting arms 38 may be connected to cover 18 and carriage 16 , respectively, in any known manner, such as by bolts.
With cover 18 connected to carriage 16 , as described in detail above, carriage 16 may be slid along cooking surface 12 to position carriage 16 and cover 18 in the desired orientation. Additionally, handle 44 is positioned within slot 46 of second end 22 of carriage 16 , allowing a user to grasp handle 44 to facilitate movement of carriage 16 and/or cover 18 . As shown in FIG. 5 , guide bar 48 may be utilized to direct movement of carriage 16 . Specifically, tab 50 of first end 20 of carriage 16 may be positioned within clamp 52 . Clamp 52 is then attached to guide bar 48 via rollers 54 and support block 56 . Guide bar 48 may then be secured to brackets 58 via bolts 60 . With carriage 16 connected to guide bar 48 , as shown in FIGS. 3 and 4 , guide bar 48 will direct movement of carriage 16 in the direction of arrows A of FIG. 1 . As shown in FIG. 5 , movement of carriage 16 will be limited by rollers 54 and brackets 58 .
Second end 22 of carriage 16 can, in certain embodiments, include guide members, such as wheels 62 or other components designed to reduce friction between carriage 16 and cooking surface 12 , which facilitate movement of carriage 16 . In this embodiment, wheels 62 can cooperate with a guide bar similar to guide bar 48 positioned adjacent second end 22 to direct movement of carriage 16 along cooking surface 12 . Additionally, as shown in FIGS. 1-4 , carriage 16 may be positioned with wall 64 of griddle 14 separating guide bar 48 , and its related components described above, from cooking surface 12 . In this embodiment, guide bar 48 and its related components are prevented from contacting food cooking on cooking surface 12 . To facilitate cleaning of passive heater 10 or allow it to be used on another cooking surface, carriage 16 (together with passive heater 10 ) may be removed from clamp 52 , as shown in FIG. 6 , and separated from guide bar 48 .
In use, passive heater 10 may cover and/or cap food items cooking on cooking surface 12 . With reference to FIG. 1 , passive heater 10 may be positioned over a row of food items, such as hamburgers 66 . While the operation of passive heater 10 is described and depicted herein with specific reference to hamburgers 66 , the passive heater of the present invention may be utilized with any food items positioned on a cooking surface, such as eggs, chicken, and sausage. Once in this position, cover 18 may be moved from a lifted position, shown in FIGS. 1 and 3 , to a lowered position, shown in FIGS. 2 and 4 , in which bottom surfaces 32 of cover 18 contact cooking surface 12 . Referring to FIG. 3 , when cover 18 is in the lifted position ( FIGS. 1 and 3 ), protrusion 72 of resiliently deformable retainer 74 contacts bottom surface 32 of cover 18 to retain cover 18 in the lifted position. Retainer 74 is secured to second end 22 of carriage 16 by screw 76 . However, retainer 74 may be secured to carriage 16 in any known manner, such as by rivets. To move cover 18 from the lifted position ( FIGS. 1 and 3 ) to the lowered position ( FIGS. 2 and 4 ), a downward force is exerted on handle 44 . When the force on handle 44 is sufficient to deform retainer 74 toward second end 22 of carriage 16 , cover 18 can be moved to the lowered position until bottom 32 contacts cooking surface 12 .
With cover 18 in the lowered position ( FIGS. 2 and 4 ), retainer 74 moves into an unbiased position extending toward first end 20 of carriage 16 . To move cover 18 back into the lifted position ( FIGS. 1 and 3 ), an upward force is exerted on handle 44 . When the force exerted on handle 44 is great enough to sufficiently deform retainer 74 toward second end 22 , cover 18 may be moved upward until bottom surface 32 of cover 18 pass protrusion 72 of retainer 74 . The force exerted on handle 44 may be released and cover 18 is held in the lifted position ( FIGS. 1 and 3 ) by the interaction of protrusion 72 of retainer 74 with bottom surface 32 of cover 18 . During movement of cover 18 from the lifted position to the lowered position, and vice versa, the position of carriage 16 may be maintained.
Referring to FIG. 4 , when cover 18 is positioned over a row of hamburgers 66 and moved into the lowered position, as described above, passive heater 10 functions as a barrier to prevent the escape of thermal energy from cooking surface 12 near hamburgers 66 , as well as from hamburgers 66 themselves. Specifically, cover 18 retains heated air and moisture near hamburgers 66 to speed the cooking thereof. Thus, even after being “flipped”, upper surface 68 of hamburgers 66 , which are no longer in contact with cooking surface 12 , may continue to cook, providing a fully cooked hamburger in less time. Additionally, once hamburgers 66 are substantially fully cooked, cheese may be placed thereon and cover 18 lowered to quickly melt the same.
With cover 18 in the position shown in FIGS. 2 and 4 , a second row (not shown) of hamburgers 66 may be placed adjacent to the first row positioned under cover 18 . In this exemplary embodiment, the area of cover 18 is less than one-half the area of cooking surface 12 . Thus, once hamburgers 66 positioned beneath cover 18 are fully cooked, which may be determined by measuring the total cook time, cover 18 may be raised and carriage 16 may be moved to center cover 18 above the second row of hamburgers 66 (not shown). Cover 18 can then be moved from the lifted position to the lowered position and contact between cooked and uncooked hamburgers 66 is substantially prevented.
In one exemplary embodiment, cover 18 may be moved from a lifted position, shown in FIG. 1 , to a lowered position, in which bottom surfaces 32 of cover 18 are spaced apart from cooking surface 12 by a predetermined distance. In this embodiment, connecting arms 38 are shortened by a predetermined amount, corresponding to the predetermined distance, to position bottom surfaces 32 above cooking surface 12 . Specifically, when cover 18 is in the lowered position, connecting arms 38 extend substantially perpendicularly to cooking surface 12 and space bottom surfaces 32 the predetermined distance from cooking surface 12 . This allows cover 18 to cap hamburgers 66 . By capping hamburgers 66 , enough thermal energy to heat upper surface 68 of hamburgers 66 is retained beneath cover 18 , while additional thermal energy may escape through the space between cooking surface 12 and cover 18 . This allows the user to accommodate variations in cooking temperatures of different food items, for example. In another exemplary embodiment, a detent mechanism may be used to retain cover 18 at a midpoint where bottom surfaces 32 of cover 18 are spaced apart from cooking surface 12 by a predetermined distance. In this embodiment, the detent mechanism may allow for bottom surfaces 32 of cover 18 to be positioned and retained at a plurality of different predetermined distances from cooking surface 12 . Additionally, in one exemplary embodiment, the detent mechanism may further allow cover 18 to be positioned with bottom surfaces 32 contacting cooking surface 12 .
In another exemplary embodiment, tabs 70 , shown in FIG. 6 , are connected to bottom surfaces 32 such that they extend downward therefrom and toward cooking surface 12 . Thus, when cover 18 is moved to the lowered position, tabs 70 contact the cooking surface and retain bottom surfaces 32 of cover 18 spaced apart from cooking surface 12 , as described in detail above. Further, an additional pair of tabs 70 may be positioned on the opposing side of cover 18 opposite the pair of tabs 70 shown in FIG. 6 . While described and depicted herein as opposing pairs of tabs, a plurality of tabs 70 may be provided in any number and may take any configuration, such as extending for bottom surfaces 32 of cover 18 at opposing ends of cover 18 .
Advantageously, the use of tabs 70 prevents connecting arms 38 from extending downward into a vertical position relative to cooking surface 12 . This allows for cover 18 to move substantially vertically when handle 44 is initially raised. In contrast, when connecting arms 38 are in a vertical position relative to cooking surface 12 , the first movement of handle 44 away from cooking surface 12 results in cover 18 moving substantially horizontally relative to cover 18 .
In one exemplary embodiment, bottom surface 32 of cover 18 is positioned between cooking surface 12 and upper surface 68 of hamburgers 66 . In another exemplary embodiment, passive heater 10 is configured so that when cover 18 is in the lowered position, cover 18 is no more than three inches from cooking surface 12 and bottom surface 32 extends below the top surface of the food to be cooked.
While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
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A passive heater including a carriage actuatable to move along a cooking surface and a cover. In one exemplary embodiment, the carriage may be positioned on a guide bar to direct movement of the carriage along the cooking surface. The cover may be connected to the carriage and positionable near the cooking surface. Advantageously, positioning the cover near the cooking surface provides for the retention of nearby heat. Thus, the top surface of a food item cooking on the cooking surface may be heated by placing the cover over the food item. In another exemplary embodiment, the cover has a lifted position and a lowered position. By moving the cover from the lifted position to the lowered position, the cover may contact the cooking surface to surround food cooking thereon. In another exemplary embodiment, the lowered positioned may be spaced upwardly from the cooking surface, allowing the cover to cap food thereon.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention concerns a cooling device for arrangement between two gradient coil windings of a gradient coil for dissipation of the heat (arising upon current being fed to the gradient coil windings) by means of a coolant flowing through one or more coolant channels in the cooling device.
[0003] 2. Description of the Prior Art
[0004] Gradient coils have in a known manner, a number of conductor structures cast in a resin matrix (for the most part epoxy resin) that are fed with current to generate spatially-resolved three-axis magnetic fields. Gradient currents of several hundred amperes at voltages of up to 2 kV are typical and lead to power losses of 10 kW and more, and must be dissipated in the form of heat. Cooling devices are therefore cast in the coil that are embedded between the individual coil supports in order to be able to discharge the dissipated power as effectively as possible. The thermal resistance between the heat sources (thus the gradient coil windings) and the heat sinks (thus the coolant medium) should be optimally slight, which is why the distance from the cooling devices to the coil conductors should be as small as possible given an optimally large heat exchanger area.
[0005] A known cooling device has a thin supporting plate on which meandering cooling tubes with round cross-section are wound. The cooling tubes, of which several hundred meters are typically required in a number of parallel cooling circuits per coil, must be manually conducted through bores in the support plate and fixed until knotted waxed silk cords. The cooling tubes are laid such that the tube ends for the water inlet and outlet are placed directly next to one another, and are set at the corresponding connection parts after encasing of the entire gradient coil.
[0006] The manual connection of the cooling tubes with the support plate is very complicated and time-consuming and thus expensive. Moreover, due to the round tube cross-section only a linear contact to the heat-generating copper conductor winding (with correspondingly poor heat transfer) results.
SUMMARY OF THE INVENTION
[0007] An object of the invention is to provide a cooling device that can be produced in a simple manner and with which a good cooling capacity can be achieved.
[0008] This object is achieved in accordance with the invention by a cooling device of the aforementioned type wherein two films are connected with one another (which films are made of a thermoplastic material) that are preformed in a thermal reshaping procedure to fashion coolant channel sections that are complementary to one another to form an inherently stable coolant channel after the connection.
[0009] The invention allows the simple and cost-effective production of large-surface cooling devices. Only two larger-surface, preformed structural elements are required in the form of two plastic films made of thermoplastic material. These are locally or globally heated in a thermal reshaping procedure in order to fashion channel sections, consequently to mold channel-like recesses. The two films are provided with congruent channel section geometries so that the coolant channel sections are complementary to one another when the two films are inventively placed atop one another and are connected with one another. The films made of thermoplastic material are selected with regard to their thickness (strength) or the employed material so that the coolant channel is inherently stable, meaning that it exhibits a sufficient minimum stability and does not collapse on itself.
[0010] The inventive cooling device thus can clearly be produced extremely simply because only the two films must be preformed and connected with one another, after which the installation in the gradient coil and the casting can either immediately ensue, or the connection pieces can be connected to the coolant inlets and outlets in advance.
[0011] The films themselves are preferably reshaped by deep drawing, for which a corresponding deep draw mold is required. The film is locally or globally heated and deformed by vacuum and/or overpressure corresponding to the mold geometry.
[0012] Because gradient coils typically exhibit a cylindrical cross-section, a cooling device must also be capable of being integrated into a correspondingly curved shape. A curve is possible in the inventive cooling device insofar as it is produced from flat films and is likewise flat after the foil connection. The foils or the cooling device or the coolant channel wall or walls exhibit a certain elasticity that allows a bending of the flat cooling device by, for example, 90° or 180°. In order to achieve this, a coolant channel section is provided at least in regions with at least one film with a structure that can be deformed by a bending load (bending force), particularly in the form of grooves. Such a structure (for example like an accordion) is in particular appropriate in the region of the edge-side collection channels (if such are provided) and that are to be bent around their longitudinal axis, while in the other regions the deformability of the channel walls is typically sufficient in order to be able to compensate for expansions and compressions due to bending. This structure can be generated without further measures during the thermal reshaping procedure.
[0013] As an alternative, it is possible for the cooling device to exhibit an inherently stable, defined curve shape. Films are used for which a defined curve shape was already impressed in the reshaping procedure, for example a 90° or a 180° shape. The two preformed and pre-curved films are set atop one another to overlap the channel sections and are connected with one another so that the cooling device is also curved. This embodiment requires two different shapes for the production of the outer film and the inner film.
[0014] In an embodiment of the invention, a surface structure (for example in the form of longitudinal or transverse grooves, knobs, etc.) can be provided at least in sections in the region of the inner side of the coolant channel or channels. This surface structure serves for generation of turbulences to improve the heat transfer, as well as causing the heat transfer surface to be enlarged. This surface structuring should primarily be in regions where high power losses are to be dissipated, so the pressure loss can also be minimized.
[0015] As described, an inventive cooling device is cast in the sealing compound upon assembly in a gradient coil. For a firm connection and to avoid the formation of voids and the like it is appropriate when breakthroughs in the connection region of the films are provided to enable the passage of a sealing compound used in the manufacture of a gradient coil. The sealing compound (which is poured in a liquid state) can thus flow through the (typically used) multiple cooling devices in the region of the passages without further measures, such that a complete embedding and solid connection is provided.
[0016] The thickness of the employed film should be ≦0.5 mm. This ensures a sufficient inherent stability of the channel walls, and the heat transfer can be optimized since the distance between heat source (coil winding) and heat sink (coolant) is not unnecessarily increased by a film that is too thick. The films themselves should be thermally stable at least up to 120° C. to preclude any deformations or other negative effects from occurring in the casting.
[0017] The films can be thermally fused (welded) with one another. Alternatively, an adhesive for gluing the films can be used. The thermal fusing is particularly appropriate since this can ensue while still in the reshaping mold in a single step immediately following the thermal reshaping. The initial films are placed in the respective mold halves and are, for example, deep-drawn into these molds after heating in order to form the channel section structure. The two mold halves are then merely moved together, and the still-heated thermoplastic film material of the films is thermally fused at the featured connection points. These connection points naturally demarcate the coolant channels. During this processing step the possibility also simultaneously exists to fashion the breakthroughs in the region of the connection or fusing joints (that should be executed sufficiently wide). When the mold is subsequently opened, the finished cooling device can be extracted in a single production step.
[0018] A number of advantages can be achieved with the inventive cooling device. The device and the channel structure thereof are dimensionally stable; so no additional outlay for stabilization in the coil assembly and in the casting is required. Because the films can be arbitrarily deformed to shape the coolant channel sections, a very flat channel (and thus flat cooling structure) can be achieved. The channels can be made wide compared with round tubes; the cross-section of the individual cooling channel can be wide, but dimensioned flat in terms of its height. Arbitrary channel geometries can thereby be achieved. The channel geometry can also be optimally matched to the geometry of the heat sources, meaning that an optimal channel guidance is possible dependent on the winding route of the gradient coil windings. The pressure loss is less than given use of tubes since the length of the cooling channel ultimately lies only in the range of the coil length. The channel length and the coil length thus substantially correspond to one another. Furthermore, the risk of possible failure points or leaks is significantly less relative to a multi-layer glued design or a wound tube structure (in this case up to 650 m of tube are required in a gradient coil).
[0019] In addition to the cooling device itself, the invention also concerns a method for production of such a cooling device that is characterized by using two films made of a thermoplastic material and performing the films with coolant channel sections in a thermal reshaping procedure, and connecting the preformed films being complementary to one another to form, with the channel sections, an inherently stable coolant channel. The films are appropriately deep-drawn for reshaping, with both films being deep-drawn in respective mold parts of a common reshaping tool, and are connected with one another by movement of the two mold parts together (thus are thermally fused) immediately after the deep drawing.
[0020] As an alternative to the reshaping of the films immediately before the connection in the same reshaping tool, it is possible to use preformed films that are connected with one another in a procedure independent of the reshaping method. This can also ensue by thermal fusing or gluing. In principle other typical fusing methods (radio-frequency/ultrasound/laser fusing) are also possible for connection of the two deep-drawn films.
[0021] Furthermore, during the reshaping procedure at least one structure that is deformable (in particular in the shape of grooves or the like) given a bending load can be generated at least in one region of the coolant channel section, for which the mold can be appropriately formed. It is alternatively or additionally possible to use for the reshaping procedure a film already inherently provided (at least in sections) with a structure that is deformable given a bending load. In this case the film is fashioned with a groove profile, for example.
[0022] The formation of a deformable structure is required when only the channel section geometry is formed in the reshaping method, but the films are otherwise planar as before. The bending of the cooling device corresponding to the required radius ensues only after the connection, dependent on the position on the gradient coil. Alternatively, the invention allows the films to be shaped with a defined arc shape in the reshaping procedure. This means that no separate deflection subsequently ensues, rather the desired bend radius is innately impressed on the films. It is also possible to connect the two films with one another by moving the mold halves together immediately after the deep drawing; the removable cooling device is then a body innately curved by, for example, 90° or 180°.
[0023] Furthermore, in the reshaping procedure it is possible to generate a surface structure at least in segments at least in the region of the inner side of the coolant channel section or sections, or to use a film innately possessing such a surface structure for the reshaping method. This surface structure serves for generation of current turbulences in the channel in order to improve the heat transfer. For example, a knob profile or a surface roughening is conceivable for this purpose. This profile can be formed either in the reshaping procedure (thus by corresponding shaping with the reshaping tools) or alternatively a film that is innately profiled can be used.
[0024] Breakthroughs to enable a passage of a sealing compound used in the production of a gradient coil can also be generated in the region of the connection sections directly upon reshaping or upon or after the connection of the films.
[0025] The employed films themselves should exhibit a thickness ≦0.5 mm given a thermal stability of at least 120° C.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a plan view of an inventive cooling device.
[0027] FIG. 2 is a section view along the line II-II in FIG. 1 .
[0028] FIG. 3 is a section view along the line III-III in FIG. 1 .
[0029] FIG. 4 shows the view of FIG. 3 in a slightly curved state.
[0030] FIG. 5 is a plan view of a portion of a further embodiment of an inventive cooling device.
[0031] FIG. 6 shows the inside of a coolant channel with a surface structure of a first embodiment.
[0032] FIG. 7 is a view corresponding to FIG. 6 with a surface structure of a second embodiment.
[0033] FIG. 8 shows a further channel shape embodiment in cross-section.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] FIG. 1 shows an inventive flat cooling device 1 having (see FIG. 2 ) two separate films 2 , 3 , both comprising a thermoplastic plastic material, which films were reshaped in a reshaping method to form a specific channel geometry. Each film has been provided with coolant channel sections 4 , 5 (running vertically in the shown example) in a deep drawing method, whereby the coolant channel sections 4 , 5 connect to form a dimensionally-stable coolant channel 6 after the films 2 , 3 are placed atop one another. This coolant channel 6 runs effectively in a meandering path from the inlet 7 to the outlet 8 . Respective collection channel sections 9 (that are not shown in detail in section) are formed at the facing sides. The two films 2 , 3 are connected liquid-tight with one another in the region of the connection sections 10 in a thermal connection method. This appropriately ensues directly in the reshaping tool that has two mold parts in which the films 2 , 3 can respectively be placed and deep-drawn. The two mold parts are then moved together, causing the two films 2 , 3 to be fused with one another by the application of pressure in the region of the connection sections 10 . The finished cooling structure can then be removed from the mold.
[0035] As FIG. 2 shows, in an exemplary embodiment, the channel sections 4 , 5 being polygonal, such that overall a hexagonal shape of the coolant channel results. The cooling device 1 is typically curved (for example by 90° or 180°) for installation in the structure of a gradient coil. The walls 11 of the coolant channels 6 are thereby stressed to bend. The outer walls 11 are thereby distended somewhat, the inner walls are somewhat compressed. The film, which exhibits a thickness of les than 0.5 mm, is sufficiently elastic so that the respective distension or compression can be accommodated without further measures.
[0036] A corresponding deformable structure 12 , 13 is appropriately provided in the region of both films 2 , 3 (in the manner of an accordion structure here in the shown example; see FIG. 3 and 4 ) only in the region of the collection channels 9 . This structure also allows without further measures a bending of these collection channels 9 running transverse to the bend axis (see FIG. 4 ). The structure 12 there has been arrived at due to distension while the structure 13 was compressed. For clarity the channel walls 11 are also shown as well as the connection sections 10 . The upper channel walls 11 of the film 2 of two adjacent cooling channels 6 are clearly drawn apart from one another while the upper channel walls 11 migrate closer to one another. It would naturally be possible to also provide such a structure (then running in the same direction) at the channel walls 11 , but this is not absolutely necessary due to the inherent elasticity of the film material and the deformability of the structure.
[0037] Furthermore, as shown in partial view in FIG. 5 , breakthroughs 14 , through which a sealing material can flow in the production of the gradient coil, are then preferably fashioned wider in the region of the connection sections 10 than is shown in FIG. 2 . These breakthroughs 14 can be of any geometry as long as they enable material therethrough. They can likewise be punched (knocked) out upon movement of the mold parts together in the preferred single production step, for which the mold parts are correspondingly profiled.
[0038] FIG. 6 and 7 show an inner view of a coolant channel 6 with view of the inside, for example of the upper cooling wall 11 of the film 2 . The inside 15 of this channel wall 11 is provided with a surface structure 16 (here, for example, in the form of intersecting grooves). With this surface structure it is possible to generate turbulent flow, which is conducive to the improvement of heat transfer from the gradient coils to the coolant (for example water). Instead of the corrugation-like surface structure 16 according to FIG. 4 , grooves 17 directed inwardly can also be used as a surface structure 16 as well as knobs (not shown in detail here) or the like; the geometry can ultimately be arbitrary. This surface structure 16 is respectively directed inwards towards the inside of the channel. For example, this also enables films 2 , 3 innately occupied with the surface structure 16 (preferably over the entire surface) to be used. The surface structure would in this case be provided in all channel sections, for example. A connection of the structured films 2 , 3 is possible without further measures in spite of surface structuring because the thermoplastic material heats in the mold parts and is consequently softened, such that by pressure application the surface structures disappear in the connection and a film fusing over the entire surface results. The corresponding surface structure 16 can naturally be provided on both channel walls, thus on both films 2 , 3 .
[0039] FIG. 8 shows a principle representation of a further geometry of a coolant channel 6 . This is executed rounded on both sides so that an essentially oval cross-section shape results. Because the channel sections worked from the films via deep drawing (thus thermal reshaping) as described, any arbitrary channel geometry can clearly be realized; the corresponding shaping tool is merely to be correspondingly fashioned. This allows it to be optimally adapted to the conditions with regard to the gradient coil windings; consequently the channels also run only where the coil conductors (and consequently the heat sources) are also present. Due to the reshaping, arbitrary channel cross-sections can also be realized, which is different than given the use of cooling tubes exhibiting only a round channel cross-section.
[0040] The employed films can be formed, for example, of polycarbonate but any other thermoplastic that can be deep-drawn in a simple manner and that has a thermal stability of at least 120° C. (which is required in order to withstand the maximum temperature prevalent in the casting) can be used.
[0041] Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.
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In a cooling device for arrangement between two gradient coil windings of a gradient coil for dissipation of the heat (arising upon feeding current to the gradient coil windings) by means of a coolant flowing through one or more coolant channels in the cooling device, two films made of thermoplastic material are connected with one another, and are preformed in a thermal reshaping procedure to form coolant channel sections that are complementary to one another to form an inherently stable coolant channel after the connection.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 15/372,187, filed Dec. 7, 2016, which is a continuation of U.S. patent application Ser. No. 15/187,456, filed Jun. 20, 2016, which is a continuation of U.S. patent application Ser. No. 14/865,325, filed Sep. 25, 2015 and issued as U.S. Pat. No. 9,416,923 on Aug. 16, 2016, which is a continuation of U.S. patent application Ser. No. 14/669,963, filed on Mar. 26, 2015 and issued as U.S. Pat. No. 9,222,626 on Dec. 29, 2015, which is a continuation of U.S. patent application Ser. No. 14/299,909, filed on Jun. 9, 2014 and issued as U.S. Pat. No. 9,006,990 on Apr. 14, 2015 and a continuation of U.S. patent application Ser. No. 14/299,915, filed Jun. 9, 2014 and issued as U.S. Pat. No. 9,006,993 on Apr. 14, 2015, which are continuations of U.S. patent application Ser. No. 13/777,331, filed Feb. 26, 2013 and issued as U.S. Pat. No. 8,866,396 on Oct. 21, 2014, which is a continuation of U.S. patent application Ser. No. 12/965,019, filed Dec. 10, 2010 and issued as U.S. Pat. No. 8,382,327 on Feb. 26, 2013, which is a continuation of U.S. patent application Ser. No. 11/085,744, filed Mar. 21, 2005 and issued as U.S. Pat. No. 8,247,985 on Aug. 21, 2012, which is a continuation of U.S. patent application Ser. No. 09/782,375, filed Feb. 12, 2001 and issued as U.S. Pat. No. 7,049,761 on May 23, 2006, which claims the benefit of U.S. Provisional Application No. 60/181,744 filed Feb. 11, 2000.
FIELD OF THE INVENTION
The present invention relates to a light tube illuminated by LEDs (light emitting diodes) which are packaged inside the light tube and powered by a power supply circuit.
BACKGROUND OF THE INVENTION
Conventional fluorescent lighting systems include fluorescent light tubes and ballasts. Such lighting systems are used in a variety of locations, such as buildings and transit buses, for a variety of lighting purposes, such as area lighting or backlighting. Although conventional fluorescent lighting systems have some advantages over known lighting options, such as incandescent lighting systems, conventional fluorescent light tubes and ballasts have several shortcomings. Conventional fluorescent light tubes have a short life expectancy, are prone to fail when subjected to excessive vibration, consume high amounts of power, require a high operating voltage, and include several electrical connections which reduce reliability. Conventional ballasts are highly prone to fail when subjected to excessive vibration. Accordingly, there is a desire to provide a light tube and power supply circuit which overcome the shortcomings of conventional fluorescent lighting systems. That is, there is a desire to provide a light tube and power supply circuit which have a long life expectancy, are resistant to vibration failure, consume low amounts of power, operate on a low voltage, and are highly reliable. It would also be desirable for such a light tube to mount within a conventional fluorescent light tube socket.
SUMMARY OF THE INVENTION
Embodiments of a replacement light tube for replacing a fluorescent light tube are disclosed herein. In one embodiment, the replacement light tube for replacing a fluorescent light tube includes a bulb portion extending between a first end and a second end, the bulb portion comprising a support structure, a plurality of white light emitting diodes (LEDs) and an elongate light-transmissive cover. The support structure has a first surface extending between the first end and the second end. The plurality of LEDs are supported by the first surface and arranged between the first end and the second end. The elongate light-transmissive cover extends between the first end and the second end and over the first surface of the support structure. A first end cap and a second end cap are disposed on the first end and the second end, respectively, each configured to fit with a socket for a fluorescent light tube. A power supply circuit is configured to provide power to the plurality of LEDs. The plurality of LEDs are arranged to emit light through the elongate light-transmissive cover and at least a portion of the power supply circuit is packaged inside at least one of the end caps.
In another embodiment, the replacement light tube includes a bulb portion extending between a first end and a second end, the bulb portion comprising a support structure, a plurality of white light emitting diodes (LEDs) and an elongate light-transmissive cover. The support structure has a first surface extending between the first end and the second end. The plurality of LEDs are supported by the first surface and arranged between the first end and the second end, the LEDs being disposed along a base of a channel defined by the support structure. The elongate light-transmissive cover extends between the first end and the second end and over the first surface of the support structure. A first end cap and a second end cap are disposed on the first end and the second end, respectively, each configured to fit with a socket for a fluorescent light tube. A power supply circuit is configured to provide power to the plurality of LEDs, the power supply circuit comprising a rectifier configured to receive alternating current (AC) input from a ballast and to provide direct current (DC) output. The plurality of LEDs are arranged to emit light through the elongate light-transmissive cover and at least a portion of the power supply circuit is packaged inside at least one of the end caps.
These and other embodiments will be discussed in additional detail hereafter.
BRIEF DESCRIPTION OF THE DRAWINGS
The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:
FIG. 1 is a line drawing showing a light tube, in perspective view, which in accordance with the present invention is illuminated by LEDs packaged inside the light tube;
FIG. 2 is a perspective view of the LEDs mounted on a circuit board;
FIG. 3 is a cross-sectional view of FIG. 2 taken along lines 3 - 3 ;
FIG. 4 is a fragmentary, perspective view of one embodiment of the present invention showing one end of the light tube disconnected from one end of a light tube socket;
FIG. 5 is an electrical block diagram of a first power supply circuit for supplying power to the light tube;
FIG. 6 is an electrical schematic of a switching power supply type current limiter;
FIG. 7 is an electrical block diagram of a second power supply circuit for supplying power to the light tube;
FIG. 8 is an electrical block diagram of a third power supply circuit for supplying power to the light tube;
FIG. 9 is a fragmentary, perspective view of another embodiment of the present invention showing one end of the light tube disconnected from one end of the light tube socket; and
FIG. 10 is an electrical block diagram of a fourth power supply circuit for supplying power to the light tube.
DETAILED DESCRIPTION
FIG. 1 is a line drawing showing a light tube 20 in perspective view. In accordance with the present invention, the light tube 20 is illuminated by LEDs 22 packaged inside the light tube 20 . The light tube 20 includes a cylindrically shaped bulb portion 24 having a pair of end caps 26 and 28 disposed at opposite ends of the bulb portion. Preferably, the bulb portion 24 is made from a transparent or translucent material such as glass, plastic, or the like. As such, the bulb material may be either clear or frosted.
In a preferred embodiment of the present invention, the light tube 20 has the same dimensions and end caps 26 and 28 (e.g. electrical male bi-pin connectors, type G13) as a conventional fluorescent light tube. As such, the present invention can be mounted in a conventional fluorescent light tube socket.
The line drawing of FIG. 1 also reveals the internal components of the light tube 20 . The light tube 20 further includes a circuit board 30 with the LEDs 22 mounted thereon. The circuit board 30 and LEDs 22 are enclosed inside the bulb portion 24 and the end caps 26 and 28 .
FIG. 2 is a perspective view of the LEDs 22 mounted on the circuit board 30 . A group of LEDs 22 , as shown in FIG. 2 , is commonly referred to as a bank or array of LEDs. Within the scope of the present invention, the light tube 20 may include one or more banks or arrays of LEDs 22 mounted on one or more circuit boards 30 . In a preferred embodiment of the present invention, the LEDs 22 emit white light and, thus, are commonly referred to in the art as white LEDs. In FIGS. 1 and 2 , the LEDs 22 are mounted to one surface 32 of the circuit board 30 . In a preferred embodiment of the present invention, the LEDs 22 are arranged to emit or shine white light through only one side of the bulb portion 24 , thus directing the white light to a predetermined point of use. This arrangement reduces light losses due to imperfect reflection in a conventional lighting fixture. In alternative embodiments of the present invention, LEDs 22 may also be mounted, in any combination, to the other surfaces 34 , 36 , and/or 38 of the circuit board 30 .
FIG. 3 is a cross-sectional view of FIG. 2 taken along lines 3 - 3 . To provide structural strength along the length of the light tube 20 , the circuit board 30 is designed with a H-shaped cross-section. To produce a predetermined radiation pattern or dispersion of light from the light tube 20 , each LED 22 is mounted at an angle relative to adjacent LEDs and/or the mounting surface 32 . The total radiation pattern of light from the light tube 20 is effected by (1) the mounting angle of the LEDs 22 and (2) the radiation pattern of light from each LED. Currently, white LEDs having a viewing range between 6° and 45° are commercially available.
FIG. 4 is a fragmentary, perspective view of one embodiment of the present invention showing one end of the light tube 20 disconnected from one end of a light tube socket 40 . Similar to conventional fluorescent lighting systems and in this embodiment of the present invention, the light tube socket 40 includes a pair of electrical female connectors 42 and the light tube 20 includes a pair of mating electrical male connectors 44 .
Within the scope of the present invention, the light tube 20 may be powered by one of four power supply circuits 100 , 200 , 300 , and 400 . A first power supply circuit includes a power source and a conventional fluorescent ballast. A second power supply circuit includes a power source and a rectifier/filter circuit. A third power supply circuit includes a DC power source and a PWM (Pulse Width Modulation) circuit. A fourth power supply circuit powers the light tube 20 inductively.
FIG. 5 is an electrical block diagram of a first power supply circuit 100 for supplying power to the light tube 20 . The first power supply circuit 100 is particularly adapted to operate within an existing, conventional fluorescent lighting system. As such, the first power supply circuit 100 includes a conventional fluorescent light tube socket 40 having two electrical female connectors 42 disposed at opposite ends of the socket. Accordingly, a light tube 20 particularly adapted for use with the first power supply circuit 100 includes two end caps 26 and 28 , each end cap having the form of an electrical male connector 44 which mates with a corresponding electrical female connector 42 in the socket 40 .
The first power supply circuit 100 also includes a power source 46 and a conventional magnetic or electronic fluorescent ballast 48 . The power source 46 supplies power to the conventional fluorescent ballast 48 .
The first power supply circuit 100 further includes a rectifier/filter circuit 50 , a PWM circuit 52 , and one or more current-limiting circuits 54 . The rectifier/filter circuit 50 , the PWM circuit 52 , and the one or more current-limiting circuits 54 of the first power supply circuit 100 are packaged inside one of the two end caps 26 or 28 of the light tube 20 .
The rectifier/filter circuit 50 receives AC power from the ballast 48 and converts the AC power to DC power. The PWM circuit 52 receives the DC power from the rectifier/filter circuit 50 and pulse-width modulates the DC power to the one or more current-limiting circuits 54 . In a preferred embodiment of the present invention, the PWM circuit 52 receives the DC power from the rectifier/filter circuit 50 and cyclically switches the DC power on and off to the one or more current-limiting circuits 54 . The DC power is switched on and off by the PWM circuit 52 at a frequency which causes the white light emitted from the LEDs 22 to appear, when viewed with a “naked” human eye, to shine continuously. The PWM duty cycle can be adjusted or varied by control circuitry (not shown) to maintain the power consumption of the LEDs 22 at safe levels.
The DC power is modulated for several reasons. First, the DC power is modulated to adjust the brightness or intensity of the white light emitted from the LEDs 22 and, in turn, adjust the brightness or intensity of the white light emitted from the light tube 20 . Optionally, the brightness or intensity of the white light emitted from the light tube 20 may be adjusted by a user. Second, the DC power is modulated to improve the illumination efficiency of the light tube 20 by capitalizing upon a phenomenon in which short pulses of light at high brightness or intensity to appear brighter than a continuous, lower brightness or intensity of light having the same average power. Third, the DC power is modulated to regulate the intensity of light emitted from the light tube 20 to compensate for supply voltage fluctuations, ambient temperature changes, and other such factors that affect the intensity of white light emitted by the LEDs 22 . Fourth, the DC power is modulated to raise the variations of the frequency of light above the nominal variation of 120 to 100 Hz thereby reducing illumination artifacts caused by low frequency light variations, including interactions with video screens. Fifth, the DC power may optionally be modulated to provide an alarm function wherein light from the light tube 20 cyclically flashes on and off.
The one or more current-limiting circuits 54 receive the pulse-width modulated or switched DC power from the PWM circuit 52 and transmit a regulated amount of power to one or more arrays of LEDs 22 . Each current-limiting circuit 54 powers a bank of one or more white LEDs 22 . If a bank of LEDs 22 consists of more than one LED, the LEDs are electrically connected in series in an anode to cathode arrangement. If brightness or intensity variation between the LEDs 22 can be tolerated, the LEDs can be electrically connected in parallel.
The one or more current-limiting circuits 54 may include (1) a resistor, (2) a current-limiting semiconductor circuit, or (3) a switching power supply type current limiter.
FIG. 6 is an electrical schematic of a switching power supply type current limiter 56 . The limiter 56 includes an inductor 58 , electrically connected in series between the PWM circuit 52 and the array of LEDs 22 , and a power diode 60 , electrically connected between ground 62 and a PWM circuit/inductor node 64 . The diode 60 is designed to begin conduction after the PWM circuit 52 is switched off. In this case, the value of the inductor 58 is adjusted in conjunction with the PWM duty cycle to provide the benefits described above. The switching power supply type current limiter 56 provides higher power efficiency than the other types of current-limiting circuits listed above.
FIG. 7 is an electrical block diagram of a second power supply circuit 200 for supplying power to the light tube 20 . Similar to the first power supply circuit 100 , the second power supply circuit 200 includes a conventional fluorescent light tube socket 40 having two electrical female connectors 42 disposed at opposite ends of the socket 40 . Accordingly, a light tube 20 particularly adapted for use with the second power supply circuit 200 includes two end caps 26 and 28 , each end cap having the form of an electrical male connector 44 which mates with a corresponding electrical female connector 42 in the socket 40 .
In the second power supply circuit 200 , the power source 46 supplies power directly to the rectifier/filter circuit 50 . The rectifier/filter circuit 50 , the PWM circuit 52 , and the one or more current-limiting circuits 54 operate as described above to power the one or more arrays of LEDs 22 . The rectifier/filter circuit 50 , the PWM circuit 52 , and the one or more current-limiting circuits 54 of the second power supply circuit 200 are preferably packaged inside the end caps 26 and 28 or the bulb portion 24 of the light tube 20 or inside the light tube socket 40 .
FIG. 8 is an electrical block diagram of a third power supply circuit 300 for supplying power to the light tube 20 . Similar to the first and second power supply circuits 100 and 200 , the third power supply circuit 300 includes a conventional fluorescent light tube socket 40 having two electrical female connectors 42 disposed at opposite ends of the socket 40 . Accordingly, a light tube 20 particularly adapted for use with the third power supply circuit 300 includes two end caps 26 and 28 , each end cap having the form of an electrical male connector 44 which mates with a corresponding electrical female connector 42 in the socket 40 .
The third power supply circuit 300 includes a DC power source 66 , such as a vehicle battery. In the third power supply circuit 300 , the DC power source 66 supplies DC power directly to the PWM circuit 52 . The PWM circuit 52 and the one or more current-limiting circuits 54 operate as described above to power the one or more arrays of LEDs 22 . In the third power supply circuit 300 , the PWM circuit 52 is preferably packaged in physical location typically occupied by the ballast of a conventional fluorescent lighting system while the one or more current-limiting circuits 54 and LEDs 22 are preferably packaged inside the light tube 20 , in either one of the two end caps 26 or 28 or the bulb portion 24 .
FIG. 9 is a fragmentary, perspective view of another embodiment of the present invention showing one end of the light tube 20 disconnected from one end of the light tube socket 40 . In this embodiment of the present invention, the light tube socket 40 includes a pair of brackets 68 and the light tube 20 includes a pair of end caps 26 and 28 which mate with the brackets 68 .
FIG. 10 is an electrical block diagram of a fourth power supply circuit 400 for supplying power to the light tube 20 . Unlike the first, second, and third power supply circuits 100 , 200 , and 300 which are powered through direct electrical male and female connectors 44 and 42 , the fourth power supply circuit 400 is powered inductively. As such, the fourth power supply circuit 400 includes a light tube socket 40 having two brackets 68 disposed at opposite ends of the socket 40 . At least one bracket 68 includes an inductive transmitter 70 . Accordingly, a light tube 20 particularly adapted for use with the fourth power supply circuit 400 has two end caps 26 and 28 with at least one end cap including an inductive receiver or antenna 72 . When the light tube 20 is mounted in the light tube socket 40 , the at least one inductive receiver 72 in the light tube 20 is disposed adjacent to the at least one inductive transmitter 70 in the light tube socket 40 .
The fourth power supply circuit 400 includes the power source 46 which supplies power to the at least one inductive transmitter 70 in the light tube socket 40 . The at least one transmitter 70 inductively supplies power to the at least one receiver 72 in one of the end caps 26 and/or 28 of the light tube 20 . The at least one inductive receiver 72 supplies power to the rectifier/filter circuit 50 . The rectifier/filter circuit 50 , PWM circuit 52 , and the one or more current-limiting circuits 54 operate as described above to power the one or more arrays of LEDs 22 . In this manner, the light tube 20 is powered without direct electrical connection.
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A replacement light tube for replacing a fluorescent light tube includes a bulb portion extending between a first end and a second end, the bulb portion comprising a support structure, a plurality of white light emitting diodes (LEDs) and an elongate light-transmissive cover. The support structure has a first surface extending between the first end and the second end. The plurality of LEDs are supported by the first surface and arranged between the first end and the second end. The elongate light-transmissive cover extends between the first end and the second end and over the first surface of the support structure. A first end cap and a second end cap are disposed on the first end and the second end, respectively, each configured to fit with a socket for a fluorescent light tube. A power supply circuit is configured to provide power to the plurality of LEDs. The plurality of LEDs are arranged to emit light through the elongate light-transmissive cover and at least a portion of the power supply circuit is packaged inside at least one of the end caps.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S. application Ser. No. 13/064,987, filed Apr. 29, 2011, which was a continuation of U.S. application Ser. No. 12/801,952, filed Jul. 2, 2010, which was a continuation of U.S. application Ser. No. 12/659,980, filed Mar. 26, 2010, which issued as U.S. Pat. No. 7,797,970, which was a divisional of U.S. application Ser. No. 11/806,245, filed May 30, 2007, which issued as U.S. Pat. No. 7,743,633, which in turn claims the benefit of Korean Patent Application Nos. 2006-49501 and 2006-49482, both filed on Jun. 1, 2006, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference.
BACKGROUND
[0002] 1. Field
[0003] The present invention relates generally to a washing machine having at least one balancer, and more particularly to a washing machine having at least one balancer that increases durability by reinforcing strength and that is installed on a rotating tub in a convenient way.
[0004] 2. Description of the Related Art
[0005] In general, washing machines do the laundry by spinning a spin tub containing the laundry by driving the spin tub with a driving motor. In a washing process, the spin tub is spun forward and backward at a low speed. In a dehydrating process, the spin tub is spun in one direction at a high speed.
[0006] When the spin tub is spun at a high speed in the dehydrating process, if the laundry leans to one side without uniform distribution in the spin tub or if the laundry leans to one side by an abrupt acceleration of the spin tub in the early stage of the dehydrating process, the spin tub undergoes a misalignment between the center of gravity and the center of rotation, which thus causes noise and vibration. The repetition of this phenomenon causes parts, such as a spin tub and its rotating shaft, a driving motor, etc., to break or to undergo a reduced life span.
[0007] Particularly, a drum type washing machine has a structure in which the spin tub containing laundry is horizontally disposed, and when the spin tub is spun at a high speed when the laundry is collected on the bottom of the spin tub by gravity in the dehydrating process, the spin tub undergoes a misalignment between the center of gravity and the center of rotation, thus resulting in a high possibility of causing excess noise and vibration.
[0008] Thus, the drum type washing machine is typically provided with at least one balancer for maintaining a dynamic balance of the spin tub. A balancer may also be applied to an upright type washing machine in which the spin tub is vertically installed.
[0009] An example of a washing machine having ball balancers is disclosed in Korean Patent Publication No. 1999-0038279. The ball balancers of a conventional washing machine include racers installed on the top and the bottom of a spin tub in order to maintain a dynamic balance when the spin tub is spun at a high speed, and steel balls and viscous oil are disposed within the racers to freely move in the racers.
[0010] Thus, when the spin tub is spun without maintaining a dynamic balance due to an unbalanced eccentric structure of the spin tub itself and lopsided distribution of the laundry in the spin tub, the steel balls compensate for this imbalance, and thus the spin tub can maintain the dynamic balance.
[0011] However, the ball balancers of the conventional washing machine have a structure in which upper and lower plates formed of plastic by injection molding are fused to each other, and a plurality of steel balls are disposed between the fused plates to make a circular motion, so that the ball balancers are continuously supplied with centrifugal force that is generated when the steel balls make a circular motion, and thus are deformed at walls thereof, which reduces the life span of the balancer.
[0012] Further, the ball balancers of the conventional washing machine do not have a means for guiding the ball balancers to be installed on the spin tub in place, so that it takes time to assemble the balancers to the spin tub.
[0013] In addition, the ball balancers of the conventional washing machine have a structure in which a racer includes upper and lower plates fused to each other, so that fusion scraps generated during fusion fall down both inwardly and outwardly of the racer. The fusion scraps that fall down inwardly of the racer prevent motion of the balls in the racer, and simultaneously result in generating vibration and noise.
SUMMARY
[0014] Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a washing machine having at least one balancer that increases durability by reinforcing the strength of the balancer, which is installed on a rotating tub in a rapid and convenient way.
[0015] Another object of the present invention is to provide a washing machine having at least one balancer, in which fusion scraps generated by fusion of the balancer are prevented from falling down inward and outward of the balancer.
[0016] Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.
[0017] In order to accomplish these objects, according to an aspect of the present invention, there is provided a washing machine having a spin tub to hold laundry to be washed and at least one balancer. The balancer includes first and second housings, the first housing having at least one support for reinforcing a strength of the balancer. The first and second housings have an annular shape and are fused together to form a closed internal space.
[0018] Here, the first housing may have the cross section of an approximately “C” shape, and the support protrudes outwardly from at least one of opposite walls of the first housing.
[0019] Further, the spin tub may include at least one annular recess corresponding to the balancer such that the balancer is able to be coupled to the spin tub by being fitted within the recess.
[0020] Further, the support may protrude from the first housing and comes into contact with a wall of the recess, and guides the balancer to be maintained in the recess in place.
[0021] Also, the supports may be continuously formed along and perpendicular to the opposite walls of the first housing.
[0022] Further, the supports may be disposed parallel to the opposite walls of the first housing at regular intervals.
[0023] Meanwhile, the washing machine may be a drum type washing machine. A front member may be attached to a front end of the spin tub and a rear member may be attached to a rear end of the spin tub. The recesses may be provided at the front and rear members of the spin tub, and the balancers may be coupled to opposite ends of the spin tub at the recesses of the front and rear members.
[0024] The foregoing and/or other aspects of the present invention can be achieved by providing a washing machine having at least one balancer. The balancer includes a first housing and a second housing fused to the first housing, and the first and second housings are fused together to form at least one pocket between the first housing and the second housing, the pocket capable of collecting fusion scraps generated during fusion.
[0025] Here, the first housing may include protruding fusion ridges protruding from ends of the first housing, and the second housing may include fusion grooves receiving the fusion ridges of the first housing when the first housing and the second housing are fused together.
[0026] Further, the first housing may further include inner pocket ridges protruding from the first housing and spaced inwardly apart with respect to the fusion ridges of the first housing.
[0027] Further, the second housing may further include outer pocket flanges protruding from the second housing and being situated on outer sides of the fusion grooves when the first housing is fused together with the second housing so the outer pocket flanges are spaced apart from the fusion ridges of the first housing by a predetermined distance, causing an outer pocket to be formed between the fusion ridges and the outer pocket flanges.
[0028] Further, the second housing may include guide ridges protruding from the second housing and protruding toward the first housing to closely contact the inner pocket ridges of the first housing when the first and second housings are fused together.
[0029] Also, the balancer may further include a plurality of balls disposed within an internal space formed by fusing the first and second housings together, the balls performing a balancing function.
[0030] In addition, the washing machine may further include a spin tub disposed horizontally, and the balancers may be installed at front and rear ends of the spin tub.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] The above and other aspects, features and advantages of the present invention will be more apparent from the following detailed description of the embodiments, taken in conjunction with the accompanying drawings, in which
[0032] FIG. 1 is a sectional view illustrating a schematic structure of a washing machine according to the present invention;
[0033] FIG. 2 is a perspective view illustrating balancers according to the present invention, in which the balancers are disassembled from a spin tub;
[0034] FIG. 3 is a perspective view illustrating a balancer according to a first embodiment of the present invention;
[0035] FIG. 4 is an enlarged view illustrating section A of FIG. 1 in order to show the sectional structure of a balancer according to a first embodiment of the present invention;
[0036] FIG. 5 is a perspective view illustrating a balancer according to a second embodiment of the present invention;
[0037] FIG. 6 is an enlarged view illustrating the sectional structure of a balancer according to the second embodiment of the present invention;
[0038] FIG. 7 is a perspective view illustrating a disassembled balancer according to a third embodiment of the present invention;
[0039] FIG. 8 is a perspective view illustrating an assembled balancer according to the third embodiment of the present invention;
[0040] FIG. 9 is a partially enlarged view of FIG. 7 ; and
[0041] FIG. 10 is a sectional view taken line A-A of FIG. 8 .
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0042] Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.
[0043] Hereinafter, exemplary embodiments of the present invention will be described with reference to the attached drawings.
[0044] FIG. 1 is a sectional view illustrating the schematic structure of a washing machine according to the present invention.
[0045] As illustrated in FIG. 1 , a washing machine according to the present invention includes a housing 1 forming an external structure of the washing machine, a water reservoir 2 installed in the housing 1 and containing washing water, a spin tub 10 disposed rotatably in the water reservoir 2 which allows laundry to be placed in and washed therein, and a door 4 hinged to an open front of the housing 1 .
[0046] The water reservoir 2 has a feed pipe 5 and a detergent feeder 6 both disposed above the water reservoir 2 in order to supply washing water and detergent to the water reservoir 2 , and a drain pipe 7 installed therebelow in order to drain the washing water contained in the water reservoir 2 to the outside of the housing 1 when the laundry is completely done.
[0047] The spin tub 10 has a rotating shaft 8 disposed at the rear thereof so as to extend through the rear of the water reservoir 2 , and a driving motor 9 , with which the rotating shaft 8 is coupled, installed on a rear outer side thereof. Therefore, when the driving motor 9 is driven, the rotating shaft 8 is rotated together with the spin tub 10 .
[0048] The spin tub 10 is provided with a plurality of dehydrating holes 10 a at a periphery thereof so as to allow the water contained in the water reservoir 2 to flow into the spin tub 10 together with the detergent to wash the laundry in a washing cycle, and to allow the water to be drained to the outside of the housing 1 through a drain pipe 7 in a dehydrating cycle.
[0049] The spin tub 10 has a plurality of lifters 10 b disposed longitudinally therein. Thereby, as the spin tub 10 rotates at a low speed in the washing cycle, the laundry submerged in the water is raised up from the bottom of the spin tub 10 and then is lowered to the bottom of the spin tub 10 , so that the laundry can be effectively washed.
[0050] Thus, in the washing cycle, the rotating shaft 8 alternately rotates forward and backward by of the driving of the driving motor 9 to spin the spin tub 10 at a low speed, so that the laundry is washed. In the dehydrating cycle, the rotating shaft 8 rotates in one direction to spin the spin tub 10 at a high speed, so that the laundry is dehydrated.
[0051] When spun at a high speed in the dehydrating process, the spin tub 10 itself may undergo misalignment between the center of gravity and the center of rotation, or the laundry may lean to one side without uniform distribution in the spin tub 10 . In this case, the spin tub 10 does not maintain a dynamic balance.
[0052] In order to prevent this dynamic imbalance to allow the spin tub 10 to be spun at a high speed with the center of gravity and the center of rotation thereof matched with each other, the spin tub 10 is provided with balancers 20 or 30 according to a first or a second embodiment of the present invention (wherein only the balancer 20 according to a first embodiment is shown in FIGS. 1-4 ) at front and rear ends thereof. The structure of the balancers 20 and 30 according to the first and second embodiments of the present invention will be described with reference to FIGS. 2 through 6 .
[0053] FIG. 2 is a perspective view illustrating balancers according to the present invention, in which the balancers are disassembled from a spin tub.
[0054] As illustrated in FIG. 2 , the spin tub 10 includes a cylindrical body 11 that has open front and rear parts and is provided with the dehydrating holes 10 a and lifters 10 b, a front member 12 that is coupled to the open front part of the body 11 and is provided with an opening 14 permitting the laundry to be placed within or removed from the body 11 , and a rear member 13 that is coupled to the open rear part of the body 11 and with the rotating shaft 8 (see FIG. 1 ) for spinning the spin tub 10 .
[0055] The front member 12 is provided, at an edge thereof, with an annular recess 15 that has the cross section of an approximately “C” shape and is open to the front of the front member 12 in order to hold any one of the balancers 20 . Similarly, the rear member 13 is provided, at an edge thereof, with an annular recess 15 (not shown) that is open to the rear of the front member 12 in order to hold the other of the balancers 20 .
[0056] The front and rear members 12 and 13 are fitted into and coupled to the front or rear edges of the body 11 in a screwed fashion or in any other fashion that allows the front and rear members 12 and 13 to be maintained to the body 11 of the spin tub 10 .
[0057] The balancers 20 , which are installed in the recesses 15 of the front and rear members 12 and 13 , have an annular shape and are filled therein with a plurality of metal balls 21 performing a balancing function and a viscous fluid (not shown) capable of adjusting a speed of motion of the balls 21 .
[0058] Now, the structure of the balancers 20 and 30 according to the first and second embodiments of the present invention will be described with reference to FIGS. 3 through 6 .
[0059] FIG. 3 is a perspective view illustrating a balancer according to a first embodiment of the present invention, and FIG. 4 is an enlarged view illustrating part A of FIG. 1 in order to show the sectional structure of a balancer according to a first embodiment of the present invention.
[0060] As illustrated in FIGS. 3 and 4 , a balancer 20 according to a first embodiment of the present invention has an annular shape and includes first and second housings 22 and 23 that are fused to define a closed internal space 20 a.
[0061] The first housing 22 has first and second walls 22 a and 22 b facing each other, and a third wall 22 c connecting ends of the first and second walls 22 a and 22 b, and thus has a cross section of an approximately “C” shape. The second housing 23 has opposite edges that protrude toward the first housing 22 and that are coupled to corresponding opposite ends 22 d of the first housing 22 by heat fusion.
[0062] The opposite ends 22 d of the first housing 22 protrude outward from the first and second walls 22 a and 22 b of the first housing 22 , and the edges of the second housing 23 are sized to cover the ends 22 d of the first housing 22 .
[0063] Thus, when the balancer 20 is fitted into the recess 15 of the front member 12 of the spin tub 10 , the first and second walls 22 a and 22 b are spaced apart from a wall of the recess 15 because of the ends and edges of the first and second housings 22 and 23 which protrude outward from the first and second walls 22 a and 22 b. Further, because the first and second walls 22 a and 22 b are relatively thin, the first and second walls 22 a and 22 b are raised outward when centrifugal force is applied thereto by the plurality of balls 21 that move in the internal space 20 a of the balancer 20 in order to perform the balancing function.
[0064] In this manner, the plurality of balls 21 make a circular motion in the balancer 20 , so that the first and second walls 22 a and 22 b are deformed by the centrifugal force applied to the first and second walls 22 a and 22 b of the first housing 22 . In order to prevent this deformation, the second housing 22 is provided with supports 24 according to a first embodiment of the present invention.
[0065] The supports 24 protrude from and perpendicular to the first and second walls 22 a and 22 b of the first housing 22 which are opposite each other, and may be continued along an outer surface of the first housing 22 , thereby having an overall annular shape.
[0066] The supports 24 have a length such that they extend from the first housing 22 to contact the wall of the recess 15 . Hence, the first and second walls 22 a and 22 b are further increased in strength, and additionally function to guide the balancer 20 so as to be maintained in the recess 15 in place.
[0067] Here, when the plurality of balls 21 make a circular motion in the first housing 22 , the centrifugal force acts in the direction moving away from the center of rotation of the spin tub 10 . Hence, the centrifugal force acts on the first wall 22 a to a stronger level when viewed in FIG. 4 . Thus, the supports 24 may be formed only on the first wall 22 a.
[0068] In the balancer 20 according to the first embodiment of the present invention, when the first and second housings 22 and 23 are fused together and fitted into the recess 15 of the spin tub 10 , the supports 24 are maintained in place while positioned along the wall of the recess 15 . Finally, the balancer 20 is coupled and fixed to the front member 12 of the spin tub 10 by screws (not shown) or in any other fashion that allows the balancer 20 to be coupled to the front member 12 .
[0069] Although not illustrated in detail, the balancer 20 is similarly installed on the rear member 13 of the spin tub 10 .
[0070] The ends 22 d of the first housing 22 include fusion ridges 42 a that protrude toward the second housing 23 . The fusion ridges 42 a are inserted within fusion grooves 43 a of the second housing 23 .
[0071] FIGS. 5 and 6 correspond to FIGS. 3 and 4 , and illustrate a balancer 30 according to a second embodiment of the present invention.
[0072] The balancer 30 according to the second embodiment of the present invention has an annular shape and includes first and second housings 32 and 33 that are fused together forming an internal space 30 a therebetween in which a plurality of balls 31 are disposed. The balancer 30 according to the second embodiment of the present invention is similar to that of balancer 20 according to the first embodiment of the present invention, except the structure of supports 34 of balancer 30 is different from that of the structure of the supports 24 of balancer 20 .
[0073] As illustrated in FIGS. 5 and 6 , the supports 34 according to the second embodiment of the present invention protrude parallel to first and second walls 32 a and 32 b of a first housing 32 which are opposite each other, and the supports 34 are disposed at regular intervals along the first and second walls 32 a and 32 b. The first housing 32 further includes a third wall 32 c. Ends 22 d of the first housing 32 extend from an end of the first and second walls 32 a and 32 b.
[0074] Similar to the supports 24 according to the first embodiment, the supports 34 of the second embodiment have a length such that the supports 34 extend from the first housing 32 to contact the wall of the recess 15 . The surfaces of the supports 34 thereby abut portions of the front member 12 . Hence, the first and second walls 32 a and 32 b are further increased in strength, and additionally function to guide the balancer 30 so as to be maintained in the recess 15 in place.
[0075] Next, the construction of a balancer 40 according to a third embodiment of the present invention will be described with reference to FIGS. 7 through 10 .
[0076] FIGS. 7 and 8 are perspective views illustrating disassembled and assembled balancers according to the third embodiment of the present invention, FIG. 9 is a partially enlarged view of FIG. 7 , and FIG. 10 is a sectional view taken along line A-A of FIG. 8 .
[0077] As illustrated in FIGS. 7 and 8 , a balancer 40 includes a first housing 42 having an annular shape and a second housing 43 having an annular shape that is fused to the first housing 42 , thereby forming an annular housing corresponding to the recess 15 (see FIG. 2 ) of the spin tub 10 . The first and second housings 42 and 43 may be, for example, formed of synthetic resin, such as plastic by injection molding.
[0078] As illustrated in FIG. 9 , the first housing 42 has a cross section of an approximately “C” shape, includes fusion ridges 42 a protruding to the second housing 43 at opposite ends thereof which are coupled with the second housing 43 , and inner pocket ridges 42 b protruding to the second housing 43 spaced inwardly apart from the fusion ridges 42 a.
[0079] The second housing 43 , which is coupled to opposite ends of the first housing 42 in order to form a closed internal space 40 a for holding a plurality of balls 41 and a viscous fluid, includes fusion grooves 43 a recessed along edges thereof so as to correspond to the fusion ridges 42 a, outer pocket flanges 43 b and guide ridges 43 c. The outer pocket flanges protrude to the first housing 42 on outer sides of the fusion grooves 43 a so as to be spaced apart from the fusion ridges 42 a of the first housing 42 by a predetermined distance. The guide ridges 43 c protrude to the first housing 42 on inner sides of the fusion grooves 43 a and closely contact the inner pocket ridges 42 b of the first housing 42 .
[0080] The guide ridges 43 c of the second housing 43 move in contact with the inner pocket ridges 42 b of the first housing 42 when the second housing 43 is fitted into the first housing 42 , to thereby guide the fusion ridges 42 a of the first housing 42 to be fitted into the fusion grooves 43 a of the second housing 43 rapidly and precisely.
[0081] Thus, when the fusion ridges 42 a of the first housing 42 are fitted into the fusion grooves 43 a of the second housing 43 in order to fuse the first housing 42 with the second housing 43 , as shown in FIG. 10 , an inner pocket 40 b having a predetermined spacing is formed between the fusion ridges 42 a and inner pocket ridges 42 b, and an outer pocket 40 c having a predetermined spacing is formed between the fusion ridges 42 a and the outer pocket flanges 43 b.
[0082] In this state, when heat is generated between the fusion ridges 42 a of the first housing 42 and the fusion grooves 43 a of the second housing 43 , the fusion ridges 42 a and the fusion grooves 43 a are firmly fused with each other. At fusion, fusion scraps that are generated by heat and fall down inward of the first housing 42 are collected in the inner pocket 40 b, so that the scraps are not introduced into the internal space 40 a of the balancer 40 in which the balls 41 move. Fusion scraps falling down outward of the first housing 42 are collected in the outer pocket 40 c, and thus are prevented from falling down outward of the balancer 40 .
[0083] In the embodiments, the balancers 20 , 30 and 40 have been described to be installed on a drum type washing machine by way of example, but it is apparent that the balancers can be applied to an upright type washing machine having a structure in which a spin tub is vertically installed.
[0084] As described above in detail, the washing machine according to the embodiments of the present invention has a high-strength structure in which at least one balancer is provided with at least one support protruding outward from the wall thereof, so that, although the strong centrifugal force acts on the wall of the balancer due to a plurality of balls making a circular motion in the balancer, the wall of the balancer is not deformed. Thus, the plurality of balls can make a smooth circular motion without causing excess vibration and noise, and thus increasing the durability and life span of the balancer.
[0085] Further, the washing machine according to the embodiments of the present invention has a structure in which the balancer can be rapidly and exactly positioned in the recess of the spin tub by the supports, so that an assembly time of the balance can be reduced.
[0086] In addition, the washing machine according to the present invention has a structure in which fusion scraps generated when the balancer is fused are collected in a plurality of pockets, and thus are prevented from falling down inward and outward of the balancer, so that the internal space of the balancer, in which a plurality of balls are filled and move in a circular motion, has a smooth surface without the addition of fusion scraps. As a result, the balls are able to move more smoothly, and excess noise and vibration are minimized. The balancer may have a clear outer surface to provide a fine appearance without the fusion scraps, so that it can be exactly coupled to the spin tub without obstruction caused by the fusion scraps.
[0087] Although a few embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims and their equivalents.
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A drum type washing machine, including a housing, a spin tub to hold laundry to be washed, the spin tub rotating with respect to a horizontal axis of the washing machine, and a ball balancer coupled to the spin tub to compensate for a dynamic imbalance during rotation thereof, the ball balancer including a first plastic member and a second plastic member joined to each other to define a closed internal space in which a plurality of balls and viscous fluid are accommodated, the first plastic member having an open side, and the second plastic member adapted to cover the open side of the first plastic member. The first plastic member includes a plurality of supports formed on an outer surface thereof to establish contact with the spin tub, and the ball balancer is fastened to the spin tub via a plurality of screw members.
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RELATED FILINGS
[0001] This application is a continuation of U.S. patent application Ser. No. 12/698,960, filed Feb. 2, 2010, which is a continuation of U.S. patent application Ser. No. 12/024,058, filed Jan. 31, 2008, which is a continuation of U.S. Pat. No. 7,337,650, Issued Mar. 4, 2008 Titled—SYSTEM AND METHOD FOR ALIGNING SENSORS ON A VEHICLE the disclosures of which are incorporated herein by reference in their entirety and further incorporates by reference: U.S. Pat. No. 6,629,033, Issued Sep. 30, 2003 Titled—OPEN COMMUNICATION SYSTEM FOR REAL-TIME MULTIPROCESSOR APPLICATIONS, U.S. Pat. No. 6,771,208, Issued Aug. 3, 2004 Titled—MULTI SENSOR SYSTEM, and U.S. Pat. No. 7,146,260, Issued Dec. 5, 2006 Titled—METHOD AND APPARATUS FOR DYNAMIC CONFIGURATION OF MULTIPROCESSOR SYSTEM.
[0002] Applicants believe the above-incorporated material constitutes “essential material” within the meaning of 37 CFR 1.57(c)(1)-(3), applicants have amended the specification to expressly recite the essential material that is incorporated by reference as allowed by the applicable rules.
BACKGROUND
[0003] Next generation automotive systems such as Lane Departure Warning (LDW), Collision Avoidance (CA), Blind Spot Detection (BSD) or Adaptive Cruise Control (ACC) systems will require target information from multiple sensors including a new class of sensor called sensor apertures such as radar, image or laser, similar to those found on advanced tactical fighter aircraft. For example, one sensor aperture may be located on the front bumper of the vehicle and obtains range and azimuth information about vehicles and stationary objects in front of the vehicle. Another sensor aperture may be located on the dash of the vehicle and obtains image information about vehicles and stationary objects in front of the vehicle. Another sensor aperture may be located on the side of the vehicle and obtains either range and azimuth data or image data in order to determine velocity and track information on vehicles that pass the vehicle. These new systems must take all of the information from the multiple sensors apertures on the vehicle and compute an accurate picture of the moving objects around the vehicle; this is known as kinematic state of the targets, or Situation Awareness (SA). To do this the Situation Awareness Platform (SAP) must accurately align the sensors apertures to each other so that information about a target from one sensor aperture can be used with information about the target from a different sensor aperture. This is called Sensor Fusion (SF), this is necessary for the SAP to get an optimal kinematic state of the targets around the vehicle in order to assess threat. The sensor apertures must also be aligned to the body of the vehicle so that the SAP can determine the position and velocity of the target with respect to the vehicle; this is called Navigation Fusion (NF).
[0004] One method of aligning the sensors apertures to each other and to the vehicle is to use mechanical and optical instruments, such as auto-collimators and laser boresight tools, during the production of the vehicle. This technique is not only costly, but would be require if a sensor aperture were repaired or replaced after production. An alignment procedure would have to be performed again in order to assure the safety critical systems were reporting accurately. Also as the vehicle goes through normal wear and tear the sensor apertures would start to become misaligned and may not be noticed by the operator. This means that the data from the sensor apertures would not correlate with each other and the vehicle reference frame until the sensor apertures were aligned again. Again, this would be costly to the vehicle operator and until performed, the SAP may not provide accurate data. Therefore, a method to align the sensor apertures to each other and to the vehicle without the use of sophisticated optical tools is required. This patent addresses this problem by describing methods that can be used to align the sensor apertures to each other and to the vehicle that do not require external alignment equipment.
[0005] In a discussion of Prior Art, U.S. Pat. No. 5,245,909, Automatic Sensor Alignment, relates to systems for maintaining alignment-sensitive aircraft-borne avionics and weapons sensors in precise alignment. It further relates to methods for precisely aligning sensitive avionics for weapons system instrumentation, which is subject to vibrations causing misalignment. Whereas this disclosure relates to methods and systems that support advanced automotive systems not described in the prior art. A second key difference is the reliance of sensor data from the vehicle as part of the alignment method. Another difference is using image apertures with elements of the vehicle in the field of view of the imager and employing optical methods for determining changes to the alignment with respect to the vehicle and vehicle reference frame, then applying a compensation based on the misalignment angle measured. Finally, this system described herein does not require a reliance on boresighting and aligning any sensor to achieve a vehicle reference frame.
[0006] U.S. Pat. No. 6,202,027, Automatic Curve Sensor Calibration, describes an improved system for accurately determining the travel path of a host vehicle and the azimuth angle of a target vehicle through an automatic calibration that detects and compensates for misalignment and curve sensor drift. The difference is a reliance on observed objects and track file generation and subsequent changes to the track files over time. Whereas this patent teaches methods of alignment based force vectors, rotational rates or optically measured changes with respect to the vehicle reference frame. Essentially all observed objects are compensated for misalignment error on the observing vehicle.
[0007] U.S. Pat. No. 5,031,330, Electronic Boresight, teaches that pairs of level sensing devices can be used in a method that aligns plane surfaces to one another by tilting platforms equal to the amount misalignment measured to adjust the sensor azimuth. Whereas this patent teaches that the sensor apertures are rigidly mounted to the vehicle and correction to misalignment is done by compensation values observed with respect to the vehicle reference frame.
[0008] Different sensors can be used in vehicles to identify objects and possible collision conditions. For example, there may be an optical sensor, such as a camera, mounted to the roof of the vehicle. Another Infrared (IR) sensor may be mounted in the front grill of the vehicle. A third inertial sensor may be located in yet another location in the central portion of the vehicle. Data from these different sensors is correlated together to identify and track objects that may come within a certain vicinity of the vehicle.
[0009] The measurements from the different sensors must be translated to a common reference point before the different data can be accurately correlated. This translation is difficult because the sensors are positioned in different locations on the vehicle. For example, the sensor located inside the front bumper of the vehicle may move in one direction during a collision while the sensor located on the top of the vehicle roof may move in a different direction.
[0010] One of the sensors may also experience vibrations at a different time than the other sensor. For example, the front bumper sensor may experience a vertical or horizontal movement when the vehicle runs over an obstacle before any movements or vibrations are experienced by the roof sensor. This different movements of sensors relative to each other make is very difficult to accurately determine the precise position and orientation of the sensors when the sensor readings are taken. This makes it difficult to translate the data into common reference coordinates.
[0011] The present invention addresses this and other problems associated with the prior art.
SUMMARY OF THE INVENTION
[0012] A vehicle sensor system configured to gather sensory data 360 degrees around the vehicle, comprising of sensor apertures for gathering data such as: range (e.g. ultrasonic); range and azimuth (e.g. laser and/or radar); images (e.g. optical and/or thermal). The vehicle has sensors that align and establish a vehicle reference frame by measuring body yaw, pitch and roll rates as well as acceleration along the 3 axes of the vehicle. The imaging apertures that have a clear view of body mold lines, like hood or rear deck, will align themselves to the vehicle reference frame, those apertures that can not align using optical methods are aligned to the vehicle using accelerometers and rates sensors by reading the inertial acceleration or angular rotation to align themselves to each other. An Integrated Computing Platform (ICP) hosts the SAP software that maintains complete system alignment by determining differences in alignment and applying or updating a compensation value with respect to the vehicle body coordinates resulting in a dynamically boresighted system.
[0013] A multi-sensor system includes multiple sensors that are integrated onto the same substrate forming a unitary multi-sensor platform that provides a known consistent physical relationship between the multiple sensors. A processor can also be integrated onto the substrate so that data from the multiple sensors can be processed locally by the multi-sensor system.
[0014] The foregoing and other objects, features and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention which proceeds with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a diagram showing how a common inertial acceleration is sensed by accelerometers on each sensor and can be used to align the sensor coordinate frames.
[0016] FIG. 2 is a diagram showing the pitch angles used to determine the pitch misalignment angle of the optical sensor.
[0017] FIG. 3 is a diagram showing the yaw data that is used to determine the yaw misalignment angle of the optical sensor.
[0018] FIG. 4 is a diagram showing the roll data that is used to determine the roll misalignment angle of the optical sensor.
[0019] FIG. 5 is an image showing the top of the hood and how it is used to compute the pitch misalignment angle.
[0020] FIG. 6 is a magnified image of the hood line showing the pixels of the image.
[0021] FIG. 7 is an image showing the top of the hood and how it is used to compute the roll misalignment angle.
[0022] FIG. 8 is a magnified image of the banked hood line showing the pixels of the image.
[0023] FIG. 9 is an image showing the top of the hood and how it is used to compute the yaw misalignment angle.
[0024] FIG. 10 is a flow chart that shows the alignment process when all sensors have micro-inertials.
[0025] FIG. 11 is a flow chart that shows the alignment process when using micro-inertials and an optical sensor.
[0026] FIG. 12 is a flow chart that shows the alignment process when all of the sensors are optical.
[0027] FIG. 13 is a flow chart that shows the alignment when the sensors are on a common platform.
[0028] FIG. 14 is a block diagram of a multi-sensor system.
[0029] FIG. 15 is a block diagram of an alternate embodiment of the multi-sensor system that includes an on-board processor. FIG. 16 is a flow diagram showing how the processor in FIG. 15 operates.
[0030] FIG. 17 is detailed diagram showing how different elements in the multi-sensor system are electrically connected together.
[0031] FIG. 18 is a diagram showing how different multi-sensor systems operate together to track objects.
DETAILED DESCRIPTION
[0032] One method is to attach three axis accelerometers to each sensor and to the vehicle and use gravity and the acceleration of the vehicle, which will be sensed by the accelerometers, to align the sensor axes to each other and to the vehicle. Information from the vehicle that is available on the Car Area Network (CAN) bus will also be used to perform the calculation of the misalignment angles. FIG. 1 shows in two dimensions the relation between sensor aperture A frame, sensor aperture B frame and the vehicle body reference frame. There are two accelerometers that sense acceleration in the X and Y axes of the sensor apertures and vehicle. This problem can easily be expanded to three dimensions with another accelerometer located in the Z-axes of each sensor and vehicle.
[0033] In FIG. 1 the vehicle experiences a linear acceleration and this common acceleration is observed by the accelerometers located on sensor aperture A, sensor aperture B and the vehicle body. The accelerometers that are attached to the vehicle body are aligned to the vehicle body reference frame. By taking the difference in acceleration data from the accelerometers on sensor aperture A and sensor aperture B and inputting this data in a Kalman Filter, the misalignment angle between the two sensor apertures, .theta.sa-.theta.sb, can be computed. The same can be done between sensor aperture A and the vehicle body, and sensor aperture B and the vehicle body to compute all of the misalignment angles. This approach can be used to compute the three dimensional misalignment angles of roll, pitch and yaw between sensor apertures and the vehicle body reference frame.
[0034] The same approach can be used when the vehicle is turning and each accelerometer group experiences a centripetal acceleration. However, in this case the difference in accelerations must be compensated by the centripetal acceleration resulting from the lever arm vector between the two sensor apertures and the angular rotation of the vehicle. The angular rotation of the vehicle is sensed by a gyro triad or micro-inertial device located at the vehicle body reference frame Acomp=Asensora−wxwxR1 The input to the Kalman filter is now: Acomp−Asensorb where: Asensora is the acceleration measured by sensor A accelerometers Asensorb is the acceleration measured by sensor B accelerometers w is the angular rotation of the vehicle measured by the ref gyros x is the cross product of two vectors R1 is the lever arm vector between sensor A and sensor B Acomp is the sensor acceleration compensated for lever arm rotation.
[0035] Also if the vehicle is stationary, the accelerometer groups will sense gravity and this can be used to help compute some of the misalignment angles. Information from the vehicle CAN bus, such as wheel rotation speeds are zero, will tell the Kalman filter that the vehicle is not moving and the only sensed acceleration will be from gravity.
[0036] FIG. 10 is a flow chart showing the process when all of the sensor apertures, as well as the vehicle body, have a micro-inertial attached to them. When the vehicle is moving, the micro-inertials sense the angular rotation and/or acceleration of the vehicle and this information is the input to a Kalman filter. The filter uses this information to estimate the roll, pitch and yaw misalignment angles between a sensor aperture and the vehicle body frame. These misalignment angles are then used to rotate the sensor target data into the vehicle body frame. With all of the target data in a common reference frame the processor can fuse data from several sensors into an optimal target track file.
[0037] The second method is to use accelerometers to align the sensor apertures to each other and one of the sensor apertures is aligned to the vehicle body by using optical information from the sensor aperture itself. For example, acceleration data can be used to align sensor aperture A to sensor aperture B, but sensor aperture B is aligned to the vehicle body directly by using sensor aperture B to compute the misalignment angles between sensor aperture B and the vehicle body. Since sensor aperture A is aligned to sensor aperture B and sensor aperture B is aligned to the vehicle body, you can compute the misalignment between sensor aperture A and the vehicle body. Sensor aperture B can be a visual sensor aperture, such as a video camera, and by observing the outline of the hood and body of the vehicle using this camera, you can compute the misalignment angles between sensor aperture B and the vehicle body frame.
[0038] FIG. 2 shows that the pitch misalignment angle is the angle between the sensor aperture's X-axis and vehicle's X-axis in the vertical plane. The pitch angle between the vehicle X-axis and a line from the sensor aperture to the top point of the hood, .PHI.vehicle, can be computed from the vehicle's dimensions. The image from the sensor aperture, FIG. 5 for example, shows the top of the hood. By counting the pixels from the center of the image down to the hood, Pp, the sensor aperture pitch angle can be computed. Using a 480.times.640 pixel image, this angle can be computed to within 1 pixel, see FIG. 6 . With a vertical field of view, FOVv, the pitch angle is: .PHI.s=(Pp/480)*FOVv The pitch misalignment angle is: .PHI.misalign=.PHI.s−.PHI.vehicle.
[0039] FIG. 3 shows that the small yaw misalignment angle is the angle between the sensor aperture's X axis and vehicle's X axis in the horizontal plane. The sensor aperture image shows the left and right edges of the hood, FIG. 9 . By computing the pixels from the left hood edge or mark on the hood to the left of the image border, Pyl, and the right hood edge or mark to the right border, Pyr, the yaw angle of the sensor aperture misalignment with a horizontal field of view, FOVh is: .PSI.Misalign=((Pyl−Pyr)/2*640)*FOVh.
[0040] FIG. 4 shows that the small roll misalignment angle is the angle between the sensor aperture's Y-axis and vehicle's Y-axis in the vertical plane. The sensor aperture image shows that the hood line and the sensor aperture level lines cross to form the roll misalignment angle. This is shown in FIG. 7 . By measuring the pixels between the two lines at the edge of the image, Pr, the roll misalignment angle can be computed as follows: .THETA.Misalign=(2*Pr/640)*180/.pi. FIG. 8 shows that the hood line can be determined accurately to within a couple of pixels.
[0041] FIG. 11 is a flow chart showing the process when at least one of the sensors is an optical device. All of the sensors have a micro-inertial attached to them. The optical device can see the targets and the outline of features of the vehicle, such as the hood line. The optical sensor uses the hood line information to compute the roll, pitch and yaw misalignment angles between the optical sensor frame and the vehicle body frame.
[0042] When the vehicle is moving, the micro-inertials sense the angular rotation and/or acceleration of the vehicle. Like FIG. 10 , the Kalman filter estimates the roll, pitch and yaw misalignment angles between a sensor aperture frame and the optical sensor frame. These misalignment angles as well as the misalignment angles between the optical sensor and the vehicle body frame are then used to rotate all of the sensor target data into the vehicle body frame. Again, with all of the target data in a common reference frame the processor can fuse data from several sensors into an optimal target track file.
[0043] A third method is to use optical information from sensor aperture A and sensor aperture B to compute the misalignment between the two sensor apertures and to use optical information from sensor aperture B to compute the misalignment between sensor aperture B and the vehicle body. For example, sensor aperture A can be a ranging laser sensor aperture and it sends out multiply beams of light to detect a target. When the light is reflected from the target, sensor aperture B can also detect the reflected light in its video camera and using this information it can compute the misalignment between sensor aperture A and sensor aperture B.
[0044] FIG. 12 is a flow chart showing the process when all of the sensors on the vehicle are optical sensors. Each optical device can see targets and the outline of features of the vehicle, such as the hood or truck line. The optical sensors use this vehicle body information to compute the roll, pitch and yaw misalignment angles between the optical sensor frame and the vehicle body frame. These misalignment angles are then used to rotate the sensor target data from each sensor into the vehicle body frame. Like the two cases above, with all of the target data in a common reference frame the processor can fuse data from several sensors into an optimal target track file.
[0045] A fourth method is to collocate all of the sensor apertures into one box that is mounted on the vehicle, such as the roof, so that all sensor apertures are always aligned with respect to each other and the only alignment required is the alignment between this sensor aperture box and the vehicle body. This can be performed by using a set of accelerometers in the sensor aperture box and on the vehicle body frame or optically by using a video camera in the sensor aperture box.
[0046] FIG. 13 shows the case where all of the sensors are mounted onto one fixed platform. If one of the sensors is an optical sensor then it can be used to align the platform frame to the vehicle body frame as shown above. Once this set of misalignment angles is computed, then all of the target data from all of the sensors can be rotated to the common vehicle body reference frame. As shown above all of the target data is now in one reference frame for computing the optimal target tracks. If none of the sensors are optical, then a set of micro-inertials can be mounted on the common platform and also on the vehicle body. While the vehicle is moving the Kalman filter can now be used to compute the misalignment angles as discussed in the above paragraphs.
[0047] The systems described above can use dedicated processor systems, micro controllers, programmable logic devices, or microprocessors that perform some or all of the operations. Some of the operations described above may be implemented in software and other operations may be implemented in hardware.
[0048] For the sake of convenience, the operations are described as various interconnected functional blocks or distinct software modules. This is not necessary, however, and there may be cases where these functional blocks or modules are equivalently aggregated into a single logic device, program or operation with unclear boundaries. In any event, the functional blocks and software modules or described features can be implemented by themselves, or in combination with other operations in either hardware or software.
[0049] Having described and illustrated the principles of the invention in a preferred embodiment thereof, it should be apparent that the invention may be modified in arrangement and detail without departing from such principles. Claim is made to all modifications and variation coming within the spirit and scope of the following claims.
[0050] FIG. 14 shows a multi-sensor system 20812 that includes different sensors 20816 and 20818 that are both integrally attached to or integrally formed into the substrate 20814 . Because the two sensors 20816 and 20818 are integrated onto the same substrate 20814 , any forces experienced by sensor 20816 are also experienced by sensor 20818 . One type of material that is used for substrate 20814 is invar. Invar is a rigid metal that has been cured with respect to temperature so that its dimensions do not change with fluxuations in temperature. Any rigid material that is resilient to expansion or contraction with temperature changes can be used.
[0051] Locating the sensors 20816 and 20818 on the same substrate 20814 simplifies the cost of sensor manufacturing and installation. For example, the two sensors 20816 can be assembled onto the substrate 20814 in a factory prior to being installed on a vehicle. If the two sensors 20816 and 20818 were not mounted on the same substrate 20814 , then each sensor would have to be separately mounted on the vehicle and then calibrated to a known alignment with respect to each other. Even if the two sensors were installed correctly, changes in the shape of the vehicle due to wear, temperature, etc. over time could change the initial alignment between the two sensors.
[0052] Premounting or prefabricating the sensors 20816 and 20818 on the substrate 20814 prior to installation on a vehicle, prevents these alignment errors. Only the substrate 208 14 of the multi-sensor system 20812 has to be mounted to the vehicle, not the individual sensors 20816 and 20818 . This allows the relative position 20820 and alignment between the two sensors 20816 and 20818 to remain the same regardless of how the substrate 20814 is mounted on the vehicle.
[0053] Wiring is also simplified since only one wiring harness has to be run through the vehicle to the multi-sensor system 20812 .
[0054] In one example, the sensor 20816 senses an area 20824 and the sensor 20818 senses an area 20822 that are both coincident. One of the sensors may have a wider field of view than the other sensor. There can also be more than two sensors on substrate 20814 and any active or passive sensor that provides object detection or vehicle force measurements can be mounted onto substrate 20814 . Some examples of sensors include ultrasonic, Infra-Red (IR), video, radar, and lidar sensors.
[0055] Depending on the substrate 20814 and the types of sensors, different mounting techniques can be used. The sensors may be separate components that are glued or bolted onto the substrate 20814 . If the multi-sensor system 20812 is an integrated circuit, then the sensors 20816 and 20818 may be integrally fabricated onto a silicon or alternative temperature resilent substrate 20814 using known deposition processes.
[0056] In one example, sensor 20814 is a radar or lidar sensor and sensor 20818 is a camera. Combining a video camera sensor with a radar and/or lidar sensor on the substrate 14 provides several advantages. The camera sensor 20818 provides good angle resolution and object identification. The radar or lidar sensor 20816 on the other hand is very effective in identifying range information.
[0057] Combining the camera video sensor 20818 with the radar or lidar sensor 20816 on the same substrate 20814 allows more effective correlation of camera angle and identification data with radar or lidar range information. For example, the radar sensor 20814 may only be able to measure angle of an object to within one-half a degree. Because of the limited angle accuracy of the radar angle readings, it may not be possible to determine from the radar reading along if an oncoming vehicle is coming from the same lane of traffic or from an opposite lane of traffic.
[0058] The video sensor 20818 may be able to accurately determine the angle of an object to within one-tenth or one-one hundredth of a degree. By correlating the radar information with the camera information, the location of an on-coming vehicle can be determined more accurately.
[0059] Do to vibration differences and possible inaccuracies in sensor alignment, it may not be possible, within fractional degrees of accuracy, to correlate information with separately mounted sensors. In other words, if the camera angle varies within plus or minus one degree with respect to the radar angle, then the camera data may not be able to refine the radar measurements.
[0060] By mounting the camera sensor 20818 and the radar sensor 20816 to the same substrate 20814 , the relative position and alignment between the two sensors remains essentially the same regardless of physical effects on the vehicle. Thus, the camera data can be correlated with radar data to within fractions of a degree of accuracy.
[0061] In another example, a first sensor may detect one object out in front of the vehicle. A second sensor located somewhere else on the vehicle may detect two different objects in front of the vehicle. Because of vibrations in different parts of the vehicle, a central processor may not be able to determine which of the two objects detected by the second sensor is associated with the object detected by the first sensor. With the multi-sensor system 20812 , measurement errors caused by this vehicle vibration is cancelled since the two sensors 20816 and 20818 effectively experience the same amount of vibration at the same time.
[0062] FIG. 14 shows an alternative embodiment where a processor 20826 is mounted to the substrate 20814 . Again the processor 20826 can be a standalone component that is rigidly attached to substrate 20814 . Alternatively, the processor 20826 is a portion of the same integrated circuit that also contains the circuitry for sensors 20816 and 20818 . The processor 20826 can perform signal processing tasks for both sensor 20818 and sensor 20816 and can also handle communication and diagnostics tasks. Tracks for identified objects are sent over connection 20828 to other multi-sensor systems in the vehicle or to a vehicle control system as shown later in FIG. 18 .
[0063] In previous multi-sensor applications, each sensor was required to send all data back to the same central processing system. This takes additional time and circuitry to send all of the data over a bus. By mounting the processor 20826 in the multi-sensor system 20812 , data from both sensor 20816 and sensor 20818 can be processed locally requiring fewer reports to be sent over connection 20828 .
[0064] Referring to FIG. 16 , the processor 20826 in FIG. 14 receives radar reports from the first sensor 20816 in block 20834 . The processor 20826 receives image reports from the second sensor 20818 in block 20836 . The processor 20826 correlates the different reports in block 20838 . Since the relative position of the two sensors 20816 and 20818 are the same and possibly coincident, the processor 20826 does not have to perform as many calculations transforming sensor measurements into common body coordinates for the vehicle.
[0065] The correlation may include first determining if the reports actually identify an object in block 20840 . The processor 20826 can verify or refine object detection information from one of the sensors with the message reports received from the other sensor. If both sensors do not verify detection of the same object within some degree of certainty, then the processor system 20826 may discard the message reports or continue to analyze additional reports in block 20840 .
[0066] When an object is detected in block 20840 , the processor 20826 only has to send one report in block 20842 representing the information obtained from both sensor 20816 and sensor 20818 . This reduces the total amount of data that has to be sent either to a central controller or another multi-sensor system in block 20842 .
[0067] FIG. 17 shows in further detail the different devices that may be integrated on the multi-sensor substrate 20814 . Camera optics 20850 and radar transmit/receive modules 20852 are each connected to a Central Processing Unit (CPU) 20854 and a digital signal processor 20856 . A memory 20858 is used to store sensor data, signal processing applications and other operating system functions. The CPU 20854 is also used for conducting distributed sensor fusion as described in further detail below.
Distributed Sensor Fusion
[0068] Referring to FIG. 18 , different multi-sensor systems 20812 A- 20812 D are used for monitoring different zones around a vehicle 20860 . For example, system 20812 A monitors zone 1, system 20812 B monitors zone 2, system 20812 C monitors zone 3 and system 20812 D monitors zone 4. The CPU 20854 and digital signal processor 20856 ( FIG. 17 ) in each multi-sensor system 20812 A- 20812 D in combination with the camera and radar sensors identify and track objects autonomously, without having to communicate with a central controller 20868 in vehicle 20860 .
[0069] Whenever an object is detected, identified and tracked, a track file is created for that object in memory 20858 ( FIG. 17 ). If the object moves to another zone around the vehicle 20860 , the multi-sensor system for the zone where the object was previously detected only has to send the track files to the other multi-sensor system associated with the overlapping region.
[0070] For example, a bicycle 20865 may be initially detected by multi-sensor system 20812 A at location 20864 A in zone 1. The multi-sensor system 20812 A creates a track file containing position, speed, acceleration, range, angle, heading, etc. for the bike 20865 . As the vehicle 20860 moves, or the bike 20865 moves, or both, the bike 20865 may move into a new position 20864 B in an overlapping region 208 66 between zone 1 and zone 2. The multi-sensor system 20812 A upon detecting the bike 20865 in the overlapping region 20866 sends the latest track file for the bike 20865 to multi-sensor system 20812 B over bus 20862 . This allows the multi-sensor system 20812 B to start actively tracking bike 20865 using the track information received from multi-sensor system 20812 A.
[0071] The multi-sensor system 20812 A only has to send a few of the latest track files for the common area 20866 over connection 20864 to multi-sensor 20812 B in order for system 20812 B to maintain a track on bike 208 65 . The track files can be exchanged between any of the multi-sensor systems 20812 A- 20812 D. When there are two multi-sensor systems that have overlapping tracks for the same object, the track file with the greatest confidence of accuracy is used for vehicle warning, security, and control operations. There are known algorithms that calculate track files and calculate a degree of confidence in the track file calculations. Therefore, describing these algorithms will not be discussed in further detail.
[0072] There may be vibrational effects on the different multi-sensor systems 20812 A- 20812 D. This however does not effect the track calculations generated by the individual multi-sensor systems 20812 A- 20812 D. The only compensation for any vibration may be when the track files are translated into body coordinates when a possible control decision is made by the central controller 208 68 .
[0073] The connection 20862 can a CAN bus, wireless 802.11 link or any other type of wired or wireless link. The system described above can use dedicated processor systems, micro controllers, programmable logic devices, or microprocessors that perform some or all of the operations. Some of the operations described above may be implemented in software and other operations may be implemented in hardware.
[0074] For the sake of convenience, the operations are described as various interconnected functional blocks or distinct software modules. This is not necessary, however, and there may be cases where these functional blocks or modules are equivalently aggregated into a single logic device, program or operation with unclear boundaries. In any event, the functional blocks and software modules or features of the flexible interface can be implemented by themselves, or in combination with other operations in either hardware or software.
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A vehicle sensor system consisting of video, radar, ultrasonic or laser sensors, oriented to obtain a 360 degree view around the vehicle for the purpose of developing a situation or scene awareness. The sensors may or may not have overlapping field of views, or support the same applications, but data will be shared by all. Orientation of the sensor to the vehicle body coordinates is critical in order to accurately assess threat and respond. This system describes methods based on measuring force and rotation on each sensor and computing a dynamic alignment to first each other, then second to the vehicle.
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DEDICATORY CLAUSE
The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalties thereon.
BACKGROUND OF THE INVENTION
A basic problem of in-tube burning rockets is the temperature sensitivity of the launch motor. The propellant burning rate is a function of its ambient temperature and increases or decreases with increases or decreases in the firing temperature. This behavior results in two undesirable characteristics in the launch motor design. First, the launch motor must completely burn out in the tube at the lowest firing temperature in which the weapon will be used. This results in a longer launch tube length than that needed for the nominal temperature operation. Since this burning time can be at a value twice that obtained at high temperature, the nominal burning time of the motor must be correspondingly shorter than would be the case without a temperature dependency. A second undesireable characteristic results from the fact that the increased burning rate at high temperatures causes higher chamber pressures which must be accommodated by added weight in the motor case and thus is responsible for further increases to total launch weight. The approach that has been taken in the past to ameliorate this problem is to improve on (lessen) the temperature sensitivity of the propellant thru the use of ballistic additives. While these improvements have resulted in temperature sensitivities that are considerably lower than the early propellants, propellant compromises have been made and some temperature sensitivity still remains.
Therefore, it is on object of this invention to provide a reduction in launch motor temperature sensitivity thru hardware modification rather than propellant formulation by the incorporation of a self-regulating combination of nozzle throats.
Other objects and advantages of this invention will be obvious to those skilled in this art.
SUMMARY OF THE INVENTION
A rocket motor that has a variable area exhaust nozzle area that is provided by having symmetrically arranged open nozzles and symmetrically arranged burst discs that close other nozzles that are opened only when predetermined temperatures and pressures are reached by burning propellant of the rocket motor to rupture the burst discs and open the other nozzles.
DESCRIPTION OF THE DRAWINGS
FIG. 1, is a perspective view of a rocket motor with main nozzles and burst disc controlled nozzles, and
FIG. 2, is a graph showing the operating characteristic of a rocket motor with conventional nozzle structure compared to a rocket motor with nozzle structure in accordance with this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, the main feature of this invention is a rocket motor 8 with a multiple set of nozzles, some of which are closed by pressure activated burst discs 12. In the illustration of FIG. 1, there are seven equally sized main nozzles 10 and six smaller burst disc controlled nozzles 12 arranged in a symmetric pattern. In a low temperature firing, the motor chamber pressure is insufficient to rupture burst discs 12 and only main nozzles 10 operate. At a higher temperature, the chamber pressure reaches a value sufficient to rupture the burst diaphragms on three of the six burst disc controlled nozzles 12. The resulting increase in throat area reduces the chamber pressure to values well below those that would occur without these additional nozzles in operation. Further increases in the firing temperature result in chamber pressures that become sufficiently high to rupture the burst discs 12 of the remaining three burst disc controlled nozzles resulting once again in a decrease in chamber pressure. The number of main nozzles is immaterial since it is the total area of the nozzles that control the resulting chamber pressure. The ratio of the area of main nozzles 10 to that of the control nozzles 12 is determined by the temperature sensitivity of the selected propellant. The number of burst disc controlled nozzles 12 is a function of the temperature sensitivity desired of the launch motor. The lower the temperature sensitivity desired, the greater the number of burst discs 12 controlled nozzle sets that must be used. In the illustration provided in FIG. 1, two sets of three burst disc controlled nozzles 12 are used, one set designed to open at an intermediate pressure, and one set designed to open at a slightly higher pressure. The symmetric arrangement is choosen to avoid the occurrence of thrust misalignment that would otherwise be encountered with a nonsymmetric nozzle flow pattern.
The operating chamber pressure of the improved structual arrangement just discussed is shown as a function of the ambient firing temperature in FIG. 2. The solid line represents the operating chamber pressure curve for a conventional motor not having burst disc controlled nozzles, while the dashed line represents the operating characteristics of the improved structure incorporating the burst disc controlled nozzles 12. The conventional structure has a fixed set of nozzles having a total throat area equal to the throat area of the improved structure with half of the burst disc controlled nozzles open. By comparison, the improved structure operates at a higher chamber pressure than the conventional structure at low temperature. For this illustration, the chamber pressure of the improved structure reaches a value sufficient to rupture the burst discs at 0° F. and the chamber pressure drops to that of the conventional structure, since the total throat area of each arrangement is equal. The operating characteristics of each arrangement remains identical until a temperature of 100° F. is reached, where the chamber pressure reaches a value sufficient to rupture the remaining set of burst discs 12 and then the chamber pressure once again is reduced. The improvement in operating characteristic is evident in the narrowing of the chamber pressure range that occurs over the firing temperature range. In this example, a reduction in chamber pressure variation of over 50% is achieved.
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A rocket motor that has a main exhaust nozzle area and a secondary exhaustozzle area with the secondary exhaust nozzle area being closed by burst discs that rupture and open secondary nozzle areas when predetermined temperatures and pressures are reached when propellant is burned inside the rocket motor.
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[0001] This application is a divisional of U.S. patent application Ser. No. 11/081,005 entitled, “TECHNIQUE AND APPARATUS FOR COMPLETING MULTIPLE ZONES,” filed on Mar. 15, 2005 which is a continuation-in-part of U.S. patent application Ser. No. 10/905,073 entitled, “SYSTEM FOR COMPLETING MUTLIPLE WELL INTERVALS,” filed on Dec. 14, 2004, which is hereby incorporated by reference in its entirety.
BACKGROUND
[0002] The present invention generally relates to a technique and apparatus to complete multiple zones.
[0003] For purposes of enhancing production from a subterranean well, the layers of the well may be fractured using a pressurized proppant-containing fracturing fluid or other treating fluids such as acid. The layers typically are fractured one at time by directing fracturing fluid to the layer being fractured and isolating the other layers.
[0004] A conventional fracturing system includes surface pumps that pressurize fracturing fluid, which may be communicated downhole via the central passageway of a tubular string. The string extends downhole through a wellbore that traverses the various layers to be fractured; and the string may include valves (sleeve valves, for example) that are generally aligned with the layers so that the valves may be used to control fluid communication between the central passageway of the string and the layers. Thus, when a fracturing operation is performed on one of the layers, one of the valves is opened so that fracturing fluid may be communicated through the opened valve to the associated layer.
[0005] To remotely operate the valves from the surface of the well, the valves may contain many different size ball seats. More specifically, to target and actuate the valves, differently sized balls may be dropped into the central passageway of the string from the surface of the well. Each ball size may be uniquely associated with a different valve, so that a particular ball size is used to actuate a specific valve. The smallest ball opens the deepest valve. More particularly, a free-falling ball lodges, or is “caught” by, a ball seat of the targeted valve. To discriminate between the different valves, each ball seat of the string has a different diameter.
[0006] After a ball lodges in a ball seat, fluid flow through the central passageway of the string becomes restricted, a condition that allows fluid pressure to be applied from the surface of the well for purposes of exerting a downward force on the ball. The ball seat typically is attached to a sleeve of the valve to transfer the force to the sleeve to cause the valve to open.
[0007] The annular area that is consumed by each ball seat restricts the cross-sectional flow area through the string (even in the absence of a ball), and the addition of each valve (and ball seat) to the string further restricts the cross-sectional flow area through the central passageway of the string, as the flow through each ball seat becomes progressively more narrow as the number of ball seats increase. Thus, a large number of valves may significantly restrict the cross-sectional flow area through the string.
[0008] As an alternative to the ball seat being located in the string as part of the valves, a single activation tool may be selectively positioned in side the central passageway of the string to operate the valves. More specifically, a valve actuation tool may be lowered downhole by a conveyance mechanism (a slickline, for example) to the valve to be opened and to close previously-opened valves.
[0009] A challenge with this alternative is that the fracturing pumps at the surface of the well may need to be idled after each layer is fractured. Furthermore, each valve typically is closed after its associated fracturing operation. The reclosure of the valves demands that the seals and sealing surfaces withstand the fracturing operations without damage.
[0010] Thus, there is a continuing need for a technique and/or arrangement to address one or more of the problems that are set forth above as well as possibly address one or more problems that are not set forth above.
SUMMARY
[0011] In an embodiment of the invention, an apparatus that is usable with a well includes a string and a plurality of tools that are mounted in the string. The string includes a passageway. The tools are mounted in the string and are adapted to be placed in a state to catch objects (free-falling objects and/or pumped-down objects, as just a few examples) of substantially the same size, which are communicated downhole through the passageway.
[0012] In another embodiment of the invention, an apparatus that is usable with a well includes a tubular member, a first tool and a second tool. The tubular member includes a passageway. The first tool is attached to the tubular member, and the first tool is adapted to be placed in a state to catch a first object that is communicated through the passageway and perform an operation after catching the first object. The second tool is attached to the tubular member and is adapted to transition to a state to catch a second object communicated through the passageway in response to the operation.
[0013] In yet another embodiment of the invention, a technique that is usable with a well includes providing a string that has a plurality of tools and a passageway that extends through the tools. The technique includes without running an activation tool into the passageway; and selectively activating the tools of the string to cause each activated tool to transition from a first state in which the activated tool is configured to allow a free-falling object to pass through the passageway to a second state in which the activated tool is configured to catch the free-falling object.
[0014] Advantages and other features of the invention will become apparent from the following description, drawing and claims.
BRIEF DESCRIPTION OF THE DRAWING
[0015] FIG. 1 depicts a fracturing system according to an embodiment of the invention.
[0016] FIGS. 2 and 3 depict a valve in a closed state and before being placed in a ball catching state according to an embodiment of the invention.
[0017] FIG. 4 depicts the valve in a closed state and after being placed in a ball catching state according to an embodiment of the invention.
[0018] FIGS. 5 and 6 depict the valve in its open state according to an embodiment of the invention.
[0019] FIG. 7 is a flow diagram depicting a technique to fracture layers in a multiple layer well according to an embodiment of the invention.
[0020] FIG. 8 is a perspective view illustrating surface features on a bottom end of a collet sleeve of the valve according to an embodiment of the invention.
[0021] FIGS. 9 and 10 depict different states of a valve that uses a C-ring as a ball catcher in accordance with an embodiment of the invention.
[0022] FIG. 11 is a perspective view of a valve housing according to another embodiment of the invention.
DETAILED DESCRIPTION
[0023] Referring to FIG. 1 , an embodiment 10 of a fracturing system includes a string 12 that extends into a wellbore 11 that traverses N layers 15 (layers 15 1 , 15 2 , 15 3 . . . 15 N−1 and 15 N , depicted as examples) of the well. As depicted in FIG. 1 , the string 12 includes valves 14 (valves 14 1 , 14 2 , 14 3 . . . 14 N−1 and 14 N , depicted as examples), each of which is associated with a particular layer 15 . For example, the valve 14 3 is associated with the layer 15 3 . Thus, to fracture a particular layer 15 , the associated valve 14 (initially run downhole in a closed state) is opened by dropping a ball and pumping up, which shifts the sleeve valve open (as described below) to allow communication between the central passageway of the string 12 and the associated layer 15 . This communication, in turn, permits fracturing fluid and pressure to be routed to the associated layer 15 .
[0024] More specifically, in some embodiments of the invention, each valve 14 controls communication between a central passageway of the string 12 and an annular region that surrounds the valve 14 . When the string 12 is run downhole, all of the valves 14 are initially closed. However, the valves 14 are successively opened one at a time in a predetermined sequence (described below) for purposes of fracturing the layers 15 .
[0025] As a more specific example, in some embodiments of the invention, the valves are opened in a sequence that begins at the bottom of the string 12 with the lowest valve 14 N , proceeds uphole to the next immediately adjacent valve 14 , then to the next immediately adjacent valve 14 , etc. Thus, the valve 14 N is opened before the valve 14 N−1 , the valve 14 3 , is opened before the valve 14 2 , etc.
[0026] For purposes of opening a particular valve 14 , a free-falling or pumped-down object is deployed from the surface of the well into the central passageway of the string 12 . It is assumed below for purposes of clarifying the following discussion that the object is a spherical ball. However, it is understood that in other embodiments of the invention, other object types and/or differently-shaped objects may be used.
[0027] In some embodiments of the invention, a ball of the same dimension may be used (although different size balls may be used in other embodiments of the invention) to open all of the valves 14 , as only one of the previously-unopened valves (called the “targeted valve” herein) is in a “ball catching state” at any one time. More specifically, in accordance with some embodiments of the invention, all of the balls that are pumped or dropped downhole for purposes of opening one of the valves 14 may have diameters that vary less than approximately 0.125 inches from each other.
[0028] As described below, initially, all of the valves 14 are closed, and none of the valves 14 are in ball catching states. When a particular valve 14 opens, the valve 14 places the next valve 14 in the sequence in the ball catching state. When in the ball catching state, the valve 14 forms a seat that presents a restricted cross-sectional flow passageway to catch a ball that is dropped into the central passageway of the string 12 . For the sequence that is described above, the unopened valves 14 that are located above the unopened valve 14 that is in the ball catching state allow the ball to pass through.
[0029] After the ball lodges in the ball catcher of the targeted valve 14 , the ball significantly restricts, if not seals off, the central passageway of the string 12 below the ball so that fluid pressure may be applied above the ball to generate a force to cause the valve to open, as further described below.
[0030] As a more specific example, a ball may be dropped from the well's surface into the central passageway of the string 12 for purposes of opening a previously-unopened valve 14 N that has previously been placed in a ball catching state. In response to the fluid pressure that is applied to the resultant restricted central passageway, the valve 14 N opens to allow a fracturing operation to be performed on the associated layer 15 N . The opening of the valve 14 N , in turn, places the next valve 14 N−1 in the sequence in the ball catching state. Once the fracturing operation on the layer 15 N is complete, another ball is dropped into the central passageway of the string 12 for purposes of opening the valve 14 N−1 so that the layer 15 N−1 can be fractured. Thus, this sequence continues until the last valve 14 1 is opened, and the associated layer 15 1 is fractured.
[0031] As a more specific example, in accordance with some embodiments of the invention, FIGS. 2 and 3 depict upper 14 A and lower 14 B sections of an exemplary valve 14 that is closed and has not been placed in ball catching state (i.e., the valve 14 is in its initial states when run into the well). Thus, as depicted in FIGS. 2 and 3 , the valve 14 does not restrict its central passageway 24 . As further described below, the valve 14 may be subsequently placed in the ball catching state, a state in which the valve 14 compresses a collet sleeve 30 to form an annular seat to catch the ball.
[0032] Turning now to the specific details of the embodiment that is depicted in FIGS. 2 and 3 , in some embodiments of the invention, the valve 14 includes a generally cylindrical upper housing section 20 ( FIG. 2 ) that is coaxial with a longitudinal axis 26 of the valve 14 . The upper housing section 20 includes an opening 19 to communicate fluids (well fluid, fracturing fluid, etc.) with the portion of the string 12 that is located above and is attached to the upper housing section 20 . At its lower end, the upper housing section 20 is coaxial with and is connected to a generally cylindrical lower housing section 22 ( FIGS. 2 and 3 ). As depicted in FIG. 2 , in some embodiments of the invention, a seal such as an 0 -ring 23 may be present between the upper 20 and lower 22 housing sections.
[0033] The valve 14 includes a valve sleeve 60 ( FIG. 2 ) that is coaxial with the longitudinal axis 26 and is constructed to move longitudinally within an annular pocket 80 (see FIG. 3 ) that is formed in the upper 20 and lower 22 housing sections of the valve 14 . The central passageway of the valve sleeve 60 forms part of the central passageway 24 of the valve 14 . Upper 62 and lower 64 0 -rings circumscribe the outer surface of the sleeve 60 and form corresponding annular seals between the outer surface of the sleeve 60 and the inner surface of the housing section 20 for purposes of sealing off radial openings (not shown in FIG. 2 ) in the upper housing section 20 during the closed state (depicted in FIGS. 2 and 3 ) of the valve 14 . As further described below, when the sleeve 60 moves in a downward direction to open the valve 14 , openings in the upper housing section 20 are exposed to place the valve 14 in an open state, a state in which fluid communication occurs between the central passageway 24 of the valve 14 and the region that surrounds the valve 14 .
[0034] At its lower end, the valve sleeve 60 is connected to the upper end of the collet sleeve 30 , a sleeve whose state of radial expansion/contraction controls when the valve 14 is in the ball catching state. The collet sleeve 30 is generally coaxial with the longitudinal axis 26 . In some embodiments of the invention, the collet sleeve 30 includes a lower end 32 in which longitudinal slots 34 are formed, and these slots 34 may be regularly spaced about the longitudinal axis 26 of the collet sleeve 30 .
[0035] In its expanded state (depicted in FIG. 2 ), the lower end 32 of the collet sleeve 30 is flared radially outwardly for purposes of creating the maximum diameter through the interior of the collet sleeve 30 . Thus, as depicted in FIG. 2 , in this state of the collet sleeve 30 , an opening 38 in the lower end 32 of the sleeve 30 has its maximum inner diameter, thereby leaving the central passageway 24 unobstructed.
[0036] For purposes of radially compressing the lower end 32 of the collet sleeve 30 to place the valve 14 in its ball catching state, the valve 14 includes a mandrel 40 . The mandrel 40 is designed to slide in a downward longitudinal direction (from the position depicted in FIG. 2 ) for purposes of sliding a sleeve 48 over the lower end 32 to radially compress the lower end 32 . The mandrel 40 is depicted in FIG. 2 in a position to allow full radial expansion of the lower end 32 of the collet sleeve 30 , and thus, in this position, the mandrel 40 does not configure the collet sleeve 30 to catch a ball.
[0037] For purposes of actuating the mandrel 40 to move the mandrel 40 in a downward direction, the mandrel 40 includes a piston head 43 that has an upper surface 44 . The upper surface 44 , in turn, is in communication with a fluid passageway 42 that may be formed in, for example, the upper housing section 20 . The upper surface 44 of the piston head 43 is exposed to an upper chamber 90 (having its minimum volume in FIG. 2 ) of the valve 14 for the purpose of creating a downward force on the mandrel 40 to compress the lower end 32 of the collet sleeve 30 .
[0038] As depicted in FIG. 2 , an 0 -ring 47 forms a seal between the inner surface of the piston head 43 and the outer surface of the collet sleeve 30 ; and a lower 0 -ring 72 is located on the outside of the mandrel 40 for purposes of forming a seal between the exterior surface of the mandrel 40 and the interior surface of the upper housing section 20 . Due to these seals, the upper chamber 90 is sealed off from a lower chamber 75 , a chamber that is below a lower surface 73 of the piston head 43 . As an example, in some embodiments of the invention, the lower chamber 75 has gas such as air at atmospheric pressure or other low pressure or at a vacuum.
[0039] The lower end of the mandrel 40 is connected to the sleeve 48 that has an inner diameter that is sized to approximately match the outer diameter of the section of the collet sleeve 30 located above the flared lower end 32 . Thus, when the pressure that is exerted on the upper surface 47 of the piston head 43 creates a force that exceeds the combined upward force exerted from the chamber 75 to the lower surface 73 and the reaction force that is exerted due to the compression of the lower end 32 , the sleeve 48 restricts the inner diameter of the lower end 32 of the collet sleeve 30 to place the valve 14 in its ball catching state.
[0040] FIG. 4 depicts the upper section 14 A of the valve 14 when the valve 14 is in the ball catching state, a state in which the mandrel 40 is at its lowest point of travel. In this state, the valve sleeve 60 remains in its uppermost point of travel to keep the valve 14 closed. As shown, in this position, the outer diameter of the lower end 32 of the collet sleeve 40 is confined by the inner diameter of the sleeve 48 , and an interior annular seat 94 is formed inside the collet sleeve 30 . The seat 94 , in turn, presents a restricted inner diameter for catching a ball.
[0041] The capture of the ball on the seat 94 substantially restricts, if not seals off, the central passageway of the valve 14 above the ball from the central passageway of the valve 14 below the ball. Due to this restriction of flow, pressure may be applied from the surface of the well for purposes of exerting a downward force on the collet sleeve 30 . Because the upper end of the collet sleeve 30 is connected to the lower end of the valve sleeve 60 , when pressure is applied to the lodged ball and collet sleeve 30 , a corresponding downward force is generated on the valve sleeve 60 . The sleeve 60 may be initially retained in the upward position that is depicted in FIGS. 2 and 4 by such mechanism(s) (not depicted in the figures) as one or more detent(s), one or more shear pins, trapped low pressure, or vacuum chamber(s). However, when a sufficient downward force is applied to the valve sleeve 60 , this retention mechanism gives way to permit downward movement of the valve sleeve 60 .
[0042] Thus, to open the valve 14 , a ball is dropped from the surface of the well, and then a sufficient pressure is applied (aided by the restriction presented by the lodged ball) to cause the valve sleeve 60 to shift from its uppermost position to its lowest position, a position that is depicted in FIGS. 5 and 6 . More particularly, FIGS. 5 and 6 depict the valve 14 in its open state. As shown in FIG. 5 , in the open state, one or more radial ports 100 formed in the upper housing section 20 are exposed to the central passageway 24 of the valve 14 . Thus, in the open state, fluid, such as fracturing fluid (for example), may be communicated from the central passageway 24 of the string (see FIG. 1 ) to the annular region that surrounds the valve 14 . It is noted that when the valve 14 is closed, the radial openings 100 are scaled off between the upper 62 and lower 64 0 -rings.
[0043] Referring to FIG. 6 , due to the pressure that is exerted on the valve sleeve 60 , the assembly that is formed from the valve sleeve 60 , collet sleeve 30 , mandrel 40 and sleeve 48 travels downwardly until the bottom surface of the collet sleeve 30 and the bottom surface of the sleeve 48 reside on an annular shoulder that is formed at the bottom of the annular pocket 80 . FIG. 6 also depicts a sphere, or ball 150 , that rests on the seat 94 and has caused the valve 14 to transition to its open state.
[0044] Referring back to FIG. 5 , in the open state of the valve 14 , the passageway 70 is in fluid communication with the central passageway 24 . This is in contrast to the closed state of the valve in which the 0 -ring 68 forms a seal between the central passageway 24 and the passageway 70 , as depicted in FIGS. 2 and 4 . Therefore, in the valve's open state, fluid pressure may be communicated to the passageway 70 (see FIG. 5 ) for purposes of transitioning another valve 14 of the string 12 (see FIG. 1 ) to its ball catching state.
[0045] As a more specific example, in some embodiments of the invention, the passageway 70 may be in fluid communication with the passageway 42 of another valve 14 (the immediately adjacent valve 14 above, for example). Therefore, in response to the valve sleeve 60 moving to its lower position, a downward force is applied (through the communication of pressure through the passageways 70 and 42 ) to the mandrel 40 of another valve 14 of the string 12 . As a more specific example, in some embodiments of the invention, the passageway 70 of each valve 14 may be in fluid communication with the passageway 42 of the immediate upper adjacent valve in the string 12 . Thus, referring to FIG. 1 , for example, the passageway 70 of the valve 14 3 is connected to the passageway 42 of the valve 14 2 , and the passageway 70 of the valve 14 2 is connected to the passageway 42 of the valve 14 1 . It is noted that the valve 14 1 in the exemplary embodiment that is depicted in FIG. 1 , is the uppermost valve 14 in the string 12 . Thus, in some embodiments of the invention, the passageway 70 of the valve 14 1 may be sealed off or non-existent.
[0046] For the lowermost valve 14 N , the passageway 42 is not connected to the passageway of a lower valve. Thus, in some embodiments of the invention, the lowermost valve 14 N is placed in its ball catching state using a mechanism that is different from that described above. For example, in some embodiments of the invention, the valve 14 N may be placed in its ball catching state in response to a fluid stimulus that is communicated downhole through the central passageway of the string 12 . Thus, the lowermost valve 14 N may include a mechanism such as a rupture disc that responds to a remotely-communicated stimulus to permit a downward force to be applied to the mandrel 40 .
[0047] As another example, in some embodiments of the invention, the above-described actuator may move the mandrel 40 in a downward direction in response to a downhole stimulus that is communicated via a slickline or a wireline that are run downhole through the central passageway of the string 12 . As yet another example, the stimulus may be encoded in an acoustic wave that is communicated through the string 12 .
[0048] As another example of a technique to place the valve 14 N in its ball catching state, in some embodiments of the invention, the mandrel 40 may have a profile on its inner surface for purposes of engaging a shifting tool that is lowered downhole through the central passageway of the string 12 for purposes of moving the mandrel 40 in a downward direction to place the valve 14 N in its ball catching state. As yet another example of yet another variation, in some embodiments of the invention, the valve 14 N may be run downhole with a collet sleeve (replacing the collet sleeve 30 ) that is already configured to present a ball catching seat. Thus, many variations are possible and are within the scope of the claimed invention.
[0049] Because the valve 14 N is the last the valve in the string 12 , other challenges may arise in operating the valve 14 N . For example, below the lowest layer 15 N , there is likely to be a closed chamber in the well. If a ball were dropped on the seat 94 (see FIG. 14 , for example), the valve sleeve 60 of the valve 14 N may not shift downwardly because any movement downward may increase the pressure below the ball. Thus, in some embodiments of the invention, the string 12 includes an atmospheric chamber 17 (see FIG. 1 ) that is located below the valve 14 N . As an example, the chamber 17 may be formed in a side pocket in a wall of the string 12 . To initiate the valve 14 N for operation, a perforating gun may be lowered downhole through the central passageway of the string 12 to the position where the atmospheric chamber 17 is located. At least one perforation formed from the firing of the perforating gun may then penetrate the atmospheric chamber 17 to create the lower pressure needed to shift the valve sleeve 60 in a downward direction to open the valve 14 N .
[0050] In some embodiments of the invention, when the atmospheric chamber 17 is penetrated, a pressure signal is communicated uphole, and this pressure signal may be used to signal the valve 14 N to shift the operator mandrel 40 in a downward direction to place the valve 14 N in the ball catching state. More specifically, in some embodiments of the invention, the valve 14 N may include a pressure sensor that detects the pressure signal so that an actuator of the valve 14 N may respond to the pressure signal to move the mandrel 40 in the downward direction to compress the lower end 32 of the collet sleeve 30 .
[0051] Alternatively, in some embodiments of the invention, the collet sleeve 30 of the valve 14 N may be pre-configured so that the seat 94 is already in its restricted position when the string 12 is run into the well. A perforating gun may then be lowered through the central passageway of the string 12 for purposes of piercing the atmospheric chamber 17 to allow downward future movement of the sleeve valve 60 , as described above.
[0052] Referring to FIG. 7 , in some embodiments of the invention, a technique 200 may be used for purposes of fracturing multiple layers of a subterranean well. The technique 200 is used in conjunction with a string that includes valves similar to the ones that are described above, such as the string 12 that contains the valves 14 (see FIG. 1 ).
[0053] Pursuant to the technique 200 , the lowest valve of the string is placed in its ball catching state, as depicted in block 202 . Next, the technique 200 begins an iteration in which the valves are opened pursuant to a sequence (a bottom-to-top sequence, for example). In each iteration, the technique 200 includes dropping the next ball into the string 12 , as depicted in block 204 . Next, pressure is applied (block 206 ) to the ball to cause the valve to open and place another valve (if another valve is to opened) in the ball catching state. Subsequently, the technique 200 includes performing (block 208 ) fracturing in the layer that is associated with the opened valve. If another layer is to be fractured (diamond 210 ), then the technique 200 includes returning to block 204 to perform another iteration.
[0054] As a more specific example, in some embodiments of the invention, the lowest valve 15 N (see FIG. 1 ) may be open via a rupture disc and an atmospheric chamber. More specifically, the string 12 is pressured up, the rupture disc breaks and then fluid pushes on side of a piston. The other side of this piston is in contact with an atmospheric chamber or a vacuum chamber.
[0055] Contrary to conventional strings that use ball catching valves, the valves 14 are not closed once opened, in some embodiments of the invention. Furthermore, in some embodiments of the invention, each valve 14 remains in its ball catching state once placed in this state. Because the valves 14 are designed to trap a ball of the same size, the cross-sectional flow area through the central passageway of the string is not significantly impeded for subsequent fracturing or production operations.
[0056] It is noted that for an arbitrary valve 14 in the string 12 , once the valve 14 is placed in its ball catching state, the restricted diameter formed from the lower end of the collet sleeve 30 prevents a ball from below the collet sleeve 30 below from flowing upstream. Therefore, during flowback, each ball may be prevented from flowing past the lower end 32 of the collet sleeve 30 of the valve 14 above.
[0057] However, in accordance with some embodiments of the invention, each ball may be formed from a material, such as a dissolvable or frangible material, that allows the ball to disintegrate. Thus, although a particular ball may flow upstream during flowback and contact the bottom end of the collet sleeve 30 above, the ball is eventually eroded or at least sufficiently dissolved to flow upstream through the valve to open up communication through the string 12 .
[0058] In some embodiments of the invention, captured ball used to actuate a lower valve 14 may push up on the collet sleeve 30 of a higher valve in the string 12 until the collet sleeve 30 moves into an area (a recessed region formed in the lower housing 22 , for example) which has a pocket in the inner diameter to allow the collet sleeve 30 to reopen. Thus, when the collet sleeve 30 reopens, the inner diameter is no longer small enough to restrict the ball so that the ball can flow uphole. Other variations are possible and are within the scope of the appended claims.
[0059] Referring to FIG. 8 , in accordance with some embodiments of the invention, a bottom surface 252 of the lower end 32 of the collet sleeve 30 is designed to be irregular to prevent a ball that is located below the collet sleeve 30 (and has not dissolved or eroded enough to pass through) from forming a seal that blocks off fluid communication. Thus, as depicted in FIG. 8 , in some embodiments of the invention, the surface 252 may have one or more irregularities, such as a depression 252 that permits the surface 32 from becoming an effective valve seat. Other types of irregularities may be introduced to the surface 252 , such as raised portions, generally rough surfaces, etc., depending the particular embodiment of the invention.
[0060] Other embodiments are within the scope of the appended claims. For example, referring to FIG. 9 , in some embodiments of the invention, in a valve 290 (that replaces the valve 14 ) the collet sleeve 30 may be replaced by a C-ring 300 . The valve 290 has the same generally design of the valve 14 , except for the C-ring 300 and the following differences. The C-ring 300 , in some embodiments of the invention, includes a single open slot 309 when the valve is not in the ball catching state. Thus, as depicted in FIG. 9 , in this state, a mandrel 302 is located above the C-ring 300 so that the open ends 307 of the C-ring 300 do not compress to close the slot 309 . As depicted in FIG. 9 , an end 304 of the mandrel 302 may be inclined, or beveled, in some embodiments of the invention so that when the mandrel 302 slides downhole, as depicted in FIG. 10 , the ends 307 meet to close the slot 309 ( FIG. 9 ) and thus restrict the inner diameter through the C-ring 300 . In the state that is depicted in FIG. 10 , the valve is in a ball catching state, as the inner diameter has been restricted for purposes of catching a free-falling or pumped down object.
[0061] The C-ring design may be advantageous, in some embodiments of the invention, in that the C-ring 300 includes a single slot 309 , as compared to the multiple slots 34 (see FIG. 2 , for example) that are present in the collet sleeve 30 . Therefore, the C-ring design may be advantageous in that sealing is easier because less leakage occurs when the C-ring ring 300 contracts.
[0062] Referring to back to FIG. 1 , in some embodiments of the invention, the string 12 may be deployed in a wellbore (e.g., an open or uncased hole) as a temporary completion. In such embodiments, sealing mechanisms may be employed between each valve and within the annulus defined by the tubular string and the wellbore to isolate the formation zones being treated with a treatment fluid. However, in other embodiments of the invention, the string 12 may be cemented in place as a permanent completion. In such embodiments, the cement serves to isolate each formation zone.
[0063] The cementing of the string 12 may potentially block valve openings, if not for certain features of the valve 14 . For example, referring back to FIG. 5 , in some embodiments of the invention, the valve 14 may include lobes 101 that are spaced around the longitudinal axis 26 . Each lobe 101 extends radially outwardly from a main cylindrical wall 103 of the upper housing 20 , and each radial port 100 extends through one of the lobes 101 . The lobes 101 restrict the space otherwise present between the valve 14 and the wellbore to limit the amount of cement that may potentially block fluid communication between the central passageway 24 and the region outside of the valve 14 , as described in co-pending U.S. patent application Ser. No. 10/905,073 entitled, “SYSTEM FOR COMPLETING MUTLIPLE WELL INTERVALS,” filed on Dec. 14, 2004.
[0064] In accordance with some embodiments of the invention, each radial port 100 is formed from an elongated slot whose length is approximately equal to at least five times its width. It has been discovered that such a slot geometry when used in a fracturing operating allows radial deflection when pressuring up, which increases stress in the rock and thus, reduces the fracturing initiation pressure.
[0065] Depending on the particular embodiment of the invention, the valve may contain, as examples, three (spaced apart by 120° around the longitudinal axis 26 , for example) or six (spaced apart by 60° around the longitudinal axis 26 , for example) lobes 101 . In some embodiments of the invention, the valve 14 does not contain the lobes 101 . Instead, the upper housing section 20 approximates a circular cylinder, with the outer diameter of the cylinder being sized to closely match the inner diameter of the wellbore.
[0066] Other variations are possible in accordance with the various embodiments of the invention. For example, depending on the particular embodiment of the invention, each radial port 100 may have a length that is at least approximately equal to ten or (in other embodiments) is approximately equal to twenty times its length.
[0067] The radial slots 100 are depicted in FIG. 5 as being located at generally the same longitudinal position. However, in other embodiments of the invention, a valve ( FIG. 11 ) may include a valve housing 400 (replacing the upper valve housing 20 ) that includes radial slots 420 that extending along a helical, or spiral path 422 , about the longitudinal axis 26 . As shown in FIG. 11 , the valve housing 400 does not contain the radially-extending lobes. Thus, many variations are possible and are within the scope of the appended claims.
[0068] Although directional and orientational terms (such as “upward,” “lower,” etc.) are used herein to describe the string, the valve, their components and their operations, it is understood that the specific orientations and directions that are described herein are not needed to practice the invention. For example, in some embodiments of the invention, the valve sleeve may move in an upward direction to open. As another example, in some embodiments of the invention, the string may be located in a lateral wellbore. Thus, many variations are possible and are within the scope of the appended claims.
[0069] While the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
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An apparatus that is usable with a well includes a string and a plurality of tools that are mounted in the string. The string includes a passageway. The tools are mounted in the string and are adapted to be placed in a state to catch objects (free-falling objects and/or pumped-down objects, as just a few examples) of substantially the same size, which are communicated downhole through the passageway.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a United States National Phase Application of International Application PCT/EP2015/077877, filed Nov. 27, 2015, and claims the benefit of priority under 35 U.S.C. §119 of German Application 10 2014 225 707.7, filed Dec. 12, 2014, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to a longitudinal adjuster for a vehicle seat. The invention furthermore relates to a vehicle seat comprising a longitudinal adjuster of this kind.
BACKGROUND OF THE INVENTION
[0003] EP 0 752 338 B1, FR 2 767 096 B1 and EP 0 904 977 B1 each describe a longitudinal adjuster which comprises at least one lower rail and at least one upper rail, which can be moved longitudinally in relation to the lower rail, as well as an elastic element arranged on the upper rail. The elastic element is provided for the purpose of locking the upper rail to the lower rail and, in particular, is arranged on the upper rail by means of a riveted joint.
SUMMARY OF THE INVENTION
[0004] It is an object of the present invention to specify a longitudinal adjuster for a vehicle seat which is better than the prior art and to specify an improved vehicle seat.
[0005] A longitudinal adjuster according to the invention for a vehicle seat comprises at least one rail pair, comprising a lower rail and an upper rail, which can be moved longitudinally relative to the lower rail, at least one locking unit for locking the upper rail, and at least one actuating element for releasing the locking of the upper rail. The locking unit comprises at least one locking element and at least one spring element, which are in operative engagement with one another, wherein the spring element is connected to the upper rail in a form- and force-fitting manner by means of a plug-in/latching connection, and wherein the spring element applies a preloading force to the actuating element and to the locking element.
[0006] The plug-in/latching connection of the spring element to the movable upper rail makes possible improved mechanical stability of the longitudinal adjuster in comparison with the prior art since deformation of the upper rail for connection to the spring element and possible distortion of the components resulting from this are avoided. As a result, there is furthermore the possibility of producing the upper rail from a high-strength material. Mechanical stability of the plug-in/latching connection is ensured by the preloading forces produced on the actuating element and the locking element.
[0007] According to one embodiment of the invention, the spring element has at least one latching nose and at least one latching tab, which can be arranged in corresponding apertures in the upper rail to form the plug-in/latching connection.
[0008] In this case, the latching nose can be inserted into a corresponding aperture, and the latching tab can be latched in a different corresponding aperture.
[0009] According to another embodiment of the invention, the aperture corresponding to the latching nose has two regions with widths that differ in the direction of a transverse axis, wherein the latching nose has two sections with widths that differ in the direction of a transverse axis.
[0010] It is expedient here if a respective width of one region of the aperture corresponds to a width of one section of the latching nose. This enables one section of the latching nose to be passed through one region of the aperture and the other section of the latching nose to be arranged in the other region of the aperture to form the plug-in/latching connection.
[0011] To produce the preloading forces, the spring element has two spring arms, wherein one of the spring arms applies a preloading force to the actuating element and the other spring arm applies a preloading force to the locking element.
[0012] In this arrangement, the spring element is preferably designed as a leaf spring, wherein the latching nose and the latching tab are arranged at one face side end of the spring element, and the spring arms are arranged at an opposite face side end of the spring element. By virtue of the fact that the spring arms produce preloading forces at one face side end of the spring element, the spring element is preloaded in such a way that the spring element remains reliably latched in the upper rail by means of the latching nose and the latching tab.
[0013] To fix the position of the actuating element, at least in the direction of a longitudinal axis, which extends parallel to a direction of travel in this case, the actuating element comprises at least one stop, wherein one of the spring arms is in operative engagement with the stop. In this arrangement, the spring arm is preferably in operative engagement with the stop, which applies a preloading force to the actuating element.
[0014] According to another embodiment of the invention, the actuating element is mounted pivotably in a through opening of the spring element. Here, the actuating element is in the form of a rocker, wherein end sections of the actuating element are moved in opposite directions when the actuating element is pivoted.
[0015] In this case, one actuating end of the actuating element is arranged between the locking element and the upper rail. During an actuation of the actuating element, e.g. an upward pivoting movement in the direction of a vertical axis, the actuating end is moved downwards in the direction of the vertical axis and hence in the direction of the lower rail. Since the actuating end is arranged between the locking element and the upper rail, the locking element is moved away from the upper rail and the longitudinal adjuster is unlocked.
[0016] One possibility for the embodiment of the locking element here is a guide peg which is arranged on the locking element and which serves as a guide element for the locking element and serves to stabilize a movement when the locking element is moved from a locking position into an unlocking position and back again.
[0017] A vehicle seat which comprises at least one longitudinal adjuster according to the invention is furthermore provided.
[0018] Here, the vehicle seat has an improved interface for fastening a spring element operatively connected to a locking element, as compared with the prior art.
[0019] Illustrative embodiments of the invention are explained in greater detail with reference to drawings. The present invention is described in detail below with reference to the attached figures. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In the drawings:
[0021] FIG. 1 is a schematic side view showing a vehicle seat having a longitudinal adjuster;
[0022] FIG. 2 is a schematic perspective, partially transparent view showing one illustrative embodiment of a longitudinal adjuster, comprising a rail pair and a locking unit;
[0023] FIG. 3 is a schematic side view showing a section through the longitudinal adjuster in an unactuated state;
[0024] FIG. 4 is a schematic side view showing a section through the longitudinal adjuster in an actuated state;
[0025] FIG. 5 is a perspective, partially transparent view showing an upper rail with an inner locking mechanism;
[0026] FIG. 6 is a schematic exploded view showing the upper rail and a spring element before assembly;
[0027] FIG. 7 is a schematic perspective, partially transparent view showing the upper rail during the assembly of the longitudinal adjuster, wherein the spring element has been inserted into an aperture of the upper rail; and
[0028] FIG. 8 is a schematic perspective, partially transparent view showing the upper rail after assembly, wherein the spring element is latched in an aperture of the upper rail.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Referring to the drawings, parts that correspond to one another are provided with the same reference signs in all the figures.
[0030] FIG. 1 shows a vehicle seat 1 of a vehicle (not shown specifically) in side view.
[0031] Here, the arrangement of the vehicle seat 1 in the vehicle is defined by means of the coordinate system used below, comprising a vertical axis z associated with a vertical direction of the vehicle, a longitudinal axis x associated with a longitudinal direction of the vehicle, and a transverse axis y associated with a transverse direction of the vehicle.
[0032] The vehicle seat 1 has a longitudinal adjuster 3 according to the invention and an actuating element 5 . When the actuating element 5 is actuated, the vehicle seat 1 can be moved relative to the vehicle along the longitudinal axis x.
[0033] For this purpose, the vehicle seat 1 has a rail pair 7 in the direction of the longitudinal axis x on each side of the vehicle seat, each pair having a lower rail 9 and an upper rail 11 , which can be moved in relation to the lower rail 9 in the direction of the longitudinal axis x. Here, the lower rail 9 is firmly connected to the vehicle, wherein the upper rail 11 is connected to the vehicle seat 1 .
[0034] The longitudinal adjuster 3 according to the invention is described in greater detail below. For this purpose, FIGS. 2 to 8 show the longitudinal adjuster 3 in various views.
[0035] In particular, FIG. 2 shows one illustrative embodiment of the longitudinal adjuster 3 in a perspective, partially transparent view, wherein the upper rail 11 is shown as being transparent in some areas. FIG. 3 shows a section through the longitudinal adjuster 3 in an unactuated state in side view. FIG. 4 shows a section through the longitudinal adjuster 3 in an actuated state schematically in side view. FIG. 5 shows the upper rail 11 , in which the locking element 15 is arranged, in a perspective, partially transparent view. FIG. 6 shows the upper rail 11 illustrated in FIG. 5 before assembly in a perspective, partially transparent view. FIG. 7 shows the upper rail 11 during assembly in a perspective, partially transparent view, and FIG. 8 shows the upper rail 11 after assembly in a perspective, partially transparent view.
[0036] The longitudinal adjuster 3 comprises the rail pair 7 and a locking unit 13 .
[0037] The locking unit 13 is designed to lock the upper rail 11 and comprises at least one spring element 17 , a locking element 15 and the actuating element 5 .
[0038] The actuating element 5 is formed as a handle or hoop (not shown specifically) on an actuating end 5 . 1 . At an opposite unlocking end 5 . 2 , the actuating element 5 is designed as an actuating tongue, which is arranged in the upper rail 11 , in particular between the latter and the locking element 15 .
[0039] The actuating element 5 is arranged in such a way on the spring element 17 , in particular in a through opening 17 . 1 shown in FIGS. 6 to 8 , that the actuating element 5 is supported as a rocker. When the actuating end 5 . 1 is actuated to unlock the longitudinal adjuster 3 , the opposite, unlocking end 5 . 2 thus moves in an opposite direction.
[0040] The locking element 15 is in the form of a locking plate having lateral rib-shaped latching features 15 . 2 for locking the upper rail 11 . Here, the locking element 15 is positioned between the upper rail 11 and the lower rail 9 . The unlocking end 5 . 2 is arranged between the upper rail 11 and the locking element 15 , as already described above. The locking element 15 furthermore comprises a guide peg 15 . 1 , which projects upwards in the direction of the vertical axis z and which is passed through an opening in the upper rail 11 (not shown explicitly here).
[0041] According to the present illustrative embodiment, the spring element 17 is designed as a leaf spring and has two spring arms 17 . 2 , 17 . 3 , wherein one spring arm 17 . 2 exerts a substantially perpendicular spring force on the actuating element 5 . In the present case, the spring force is produced along the vertical axis z in the direction of the vehicle seat 1 . Preloading of the actuating element 5 produced by means of the spring force of spring arm 17 . 2 holds said element in a predetermined position, in which the locking element 15 is in a locking position. In the locking position, the lateral latching features 15 . 2 are in operative engagement with latching recesses 9 . 1 arranged in the lower rail 9 , these being shown in part in FIG. 2 .
[0042] Another spring arm 17 . 3 exerts a substantially perpendicular spring force on the locking element 15 , wherein the spring force holds the locking element 15 in a predetermined position, in particular in the locking position of the locking element 15 . In the present case, the spring force is produced along the vertical axis z in the direction of the vehicle seat 1 .
[0043] During a process of unlocking the longitudinal adjuster 3 , the actuating element 5 , in particular the unlocking end 5 . 2 , is actuated and moved upwards along the vertical axis z in the direction of the vehicle seat 1 . Owing to this movement, in particular the movement of the unlocking end 5 . 2 , and the design of the actuating element 5 as a rocker, the actuating element 5 counteracts the spring force produced by spring arm 17 . 2 , wherein spring arm 17 . 2 is additionally stressed, allowing the actuating end 5 . 1 to be moved back into the original position when it is released.
[0044] The upward movement of the actuating end 5 . 1 along the vertical axis z in the direction of the vehicle seat 1 furthermore brings about a movement of the unlocking end 5 . 2 in the opposite direction, by means of which the spring force of spring arm 17 . 2 is counteracted and the locking element 15 is moved downwards in the direction of the vertical axis z.
[0045] As a result of this, the operative engagement between the latching features 15 . 2 and the latching recesses 9 . 1 is released, and a longitudinal movement of the upper rail 11 relative to the lower rail 9 is enabled.
[0046] In the unlocking position, spring arm 17 . 3 is additionally stressed, ensuring that the locking element 15 is moved back in the direction of the upper rail 11 when the actuating end 5 . 1 is released. Here, the locking position of the locking element 15 is reached when the latching features 15 . 2 latch with the latching recesses 9 . 1 .
[0047] In the figure, the actuating end 5 . 1 of the actuating element 5 , said end being designed as a handle for example, is positioned in such a way that the locking element 15 is in the locking position.
[0048] The spring element 17 has a latching nose 17 . 4 , which is arranged in a corresponding aperture 11 . 1 in the upper rail 11 to form a plug-in connection. The spring element 17 furthermore has a latching tab 17 . 5 , which is arranged in a corresponding further aperture 11 . 2 in the upper rail 11 to form a latching connection and to fix a position of the latching nose 17 . 4 in aperture 11 . 1 . Together with the corresponding apertures 11 . 1 , 11 . 2 , the latching nose 17 . 4 and the latching tab 17 . 5 form a plug-in/latching connection S.
[0049] The actuating element 5 is passed through a through opening 17 . 1 . Here, the actuating element 5 is supported in such a way in the through opening 17 . 1 (in a manner not shown specifically) that the actuating element 5 is designed as a rocker, as already mentioned above. In a region of the through opening 17 . 1 , the actuating element 5 furthermore has lateral stops (not shown) in order to define and stabilize a position of the actuating element 5 in the spring element 17 .
[0050] To fix the position of the actuating element 5 , at least in the direction of the longitudinal axis x, said element has a further stop 5 . 3 , on which spring arm 17 . 2 is arranged. By virtue of the spring force produced by means of spring arm 17 . 2 , the arm is pressed against the actuating element 5 and a steady arrangement on the stop 5 . 3 is ensured.
[0051] The other spring arm 17 . 3 exerts the spring force on the locking element 15 along the vertical axis z in the direction of the vehicle seat 1 , thereby holding said locking element in the position shown.
[0052] The unlocking end 5 . 2 , which is designed as an actuating tongue, is arranged between an inner side of the upper rail 11 , said inner side facing the lower rail 9 , and the locking element 15 . Locking element 15 , on which the spring force produced by means of spring arm 17 . 3 is exerted, transmits this spring force to the unlocking end 5 . 2 , thereby pressing said end against the upper rail 11 . In order to minimize mechanical noises during an actuation of the actuating element 5 , the unlocking end 5 . 2 comprises a damping element 5 . 4 , e.g. a rubber plug or a plastic coating or a spring.
[0053] To actuate the actuating element 5 and thus unlock the longitudinal adjuster 3 , the actuating end 5 . 1 is moved along the vertical axis z in the direction of the vehicle seat 1 in accordance with the arrow P shown in FIG. 4 .
[0054] Owing to the movement of the actuating end 5 . 1 and the design of the actuating element 5 as a rocker, the actuating element 5 , in particular the unlocking end 5 . 2 , counteracts the spring forces produced by the spring arms 17 . 2 , 17 . 3 . The movement of the actuating end 5 . 1 along the vertical axis z in the direction of the vehicle seat 1 furthermore has the effect that the unlocking end 5 . 2 is moved in the opposite direction.
[0055] During this process, the locking element 15 is moved downwards along the vertical axis z and hence into the unlocking position by means of the unlocking end 5 . 2 .
[0056] The connection between the spring element 17 and the upper rail 11 is explained in greater detail below.
[0057] The upper rail 11 has the aperture 11 . 1 in a flank extending in the direction of the longitudinal axis x. The aperture 11 . 1 is of substantially T-shaped design to allow the spring element 17 (not shown here) to be accommodated in a form-fitting and force-fitting manner. In this case, the aperture 11 . 1 has two regions with different widths X 1 , X 2 in the direction of the transverse axis y, wherein the width X 1 of a region facing the locking element 15 in the direction of the longitudinal axis x is smaller than the width X 2 of the other region.
[0058] A further aperture 11 . 2 is arranged spaced apart from aperture 11 . 1 in the direction of the longitudinal axis x and is likewise provided for accommodating the spring element 17 in a form-fitting and force-fitting manner.
[0059] The spring element 17 has a latching tab 17 . 5 to enable it to be fixed in position on the upper rail 11 . The latching tab 17 . 5 is produced by means of stamping and subsequent forming, for example, or, as an alternative, is designed as a latching pin projecting from the spring element 17 or as a separate latching pin arranged on, e.g. welded on, the spring element 17 . Here, the latching tab 17 . 5 has a width corresponding to the further aperture 11 . 2 in the direction of the transverse axis y.
[0060] In the present case, the spring element 17 is of integral design, wherein the latching nose 17 . 4 has been shaped by means of stamping and subsequent forming, for example. In an illustrative embodiment which is not shown, the latching nose 17 . 4 is arranged, e.g. screwed on, by means of a force-fitting and/or form-fitting connection.
[0061] The latching nose 17 . 4 extends vertically along the vertical axis z and is of substantially T-shaped design. Here, a wide section of the latching nose 17 . 4 , which is towards the top along the vertical axis z, has a width X 3 , and a lower, narrow section has a width X 4 . In this arrangement, the width X 2 of the aperture 11 . 1 corresponds to the width X 3 of the latching nose 17 . 4 , and the width X 1 of the aperture 11 . 1 corresponds to the width X 4 of the latching nose 17 . 4 .
[0062] The spring arms 17 . 2 , 17 . 3 extend along the longitudinal axis x and are formed so as to be spaced apart in such a way that they can apply separate spring forces.
[0063] Spring arm 17 . 2 is angled in such a way along the transverse axis y at an opposite end from latching nose 17 . 4 that it is possible to produce engagement of spring arm 17 . 2 with the stop 5 . 3 of the actuating element 5 .
[0064] Spring arm 17 . 3 is of arched design at an end opposite the latching nose 17 . 4 , in such a way that an additional spring force action on the locking element 15 is achieved.
[0065] FIG. 7 shows an assembly step in which the spring element 17 , in particular the latching nose 17 . 4 , is introduced into the aperture 11 . 1 of the upper rail 11 . During this process, the upper region with the width X 3 of the latching nose 17 . 4 is passed through the wide region X 2 of aperture 11 . 1 .
[0066] FIG. 8 shows the longitudinal adjuster 3 after assembly, wherein the spring element 17 has been moved longitudinally out of a position shown in FIG. 7 in the direction of the locking element 15 . During this process, the latching nose 17 . 4 is latched into the aperture 11 . 1 of the upper rail 11 . The narrow region of the latching nose 17 . 4 is guided into the narrow region of aperture 11 . 1 , and the latching tab 17 . 5 is latched in the further aperture 11 . 2 . By means of the arrangement of the latching tab 17 . 5 in the further aperture 11 . 2 , the latching nose 17 . 4 is fixed in its position.
[0067] The described arrangement of the spring element 17 on the upper rail 11 is a plug-in/latching connection S. The preloading forces of the spring element 17 on the locking element 15 and on the actuating element 5 hold the spring element 17 in the upper rail 11 .
[0068] Forces acting externally on the actuating element 5 along the vertical axis z do not produce any moments on the spring element 17 by means of latching of the spring element 17 in the apertures 11 . 1 , 11 . 2 , which are situated in one plane. Tension and compression forces along the longitudinal axis x can be absorbed by the spring element 17 .
[0069] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
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A longitudinal adjuster ( 3 ) for a vehicle seat ( 1 ) includes at least one rail pair ( 7 ), including a lower rail ( 9 ) and an upper rail ( 11 ), which can be moved longitudinally in relation to the lower rail ( 9 ). At least one locking unit ( 13 ) locks the upper rail ( 11 ). At least one actuating element ( 5 ) releases the locking of the upper rail ( 11 ). The locking unit ( 13 ) includes at least one locking element ( 15 ) and at least one spring element ( 17 ), which are operatively engaged with each other. The spring element ( 17 ) is interlockingly and frictionally connected to the upper rail ( 11 ) by an insertion locking connection (S). The spring element ( 17 ) applies a preloading force to the actuating element ( 5 ) and to the locking element ( 15 ). A vehicle seat ( 1 ) is also provided with at least one such longitudinal adjuster ( 3 ).
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BACKGROUND OF THE INVENTION
This invention relates to a reverse power flow detector and more particularly to a solid state reverse power flow detector and control circuit.
Present day reverse power flow detectors make use of relay type devices, which, in general lack sensitivity and do not provide desired maintenance free life. It has been considered necessary in the electrical energy field to provide a more sensitive reverse power flow detector for use in the multiple application of electrical energy present in the field today. Further, it has been seen as a necessity in the electrical energy field to provide a reverse power flow detector and control circuit which would be able to function over long periods of time without requiring extensive attention or maintenance.
Therefore, it is one object of this invention to provide a reverse power flow detector which will be responsive to small increments of reverse power flow.
A further object of this invention is to provide a reverse power flow detector which will require little maintenance and have a long life.
A still further object of this invention is to provide a reverse power flow detector which utilizes substantially solid state components.
SUMMARY OF INVENTION
Briefly, in one form, this invention comprises a voltage sampling circuit in the form of a pulse generator and a current sampling circuit. The pulse generator provides an output pulse of short duration at a given time during each cycle. The current signal is used to actuate a gate, allowing the voltage pulses to trigger an SCR whenever the current reverses. The SCR actuates a relay device, through a delay circuit to control an electrical device, placing such device in a power reverse condition.
The invention which is sought to be protected will be particularly pointed out and distinctly claimed in the claims appended hereto. However, it is believed that this invention and the manner in which its various objects and advantages are obtained as well as other objects and advantages thereof will be more fully understood from reference to the following detailed description of a preferred embodiment thereof, particularly when considered in the light of the accompanying drawing.
BRIEF DESCRIPTION OF DRAWING
FIG. 1 is a schematic diagram of a preferred form of solid state reverse power flow detector and control circuit according to this invention;
FIG. 2 shows a preferred form of switching control means to switch an electrical device from power forward to power reverse condition according to this invention
DESCRIPTION OF PREFERRED EMBODIMENT
FIG. 1 shows a schematic diagram of a reverse power flow detector which, essentially, makes use of solid state components. The operation of the reverse power flow detector is based on the relationship of the voltage and current signals obtained from the monitored line. As is well known, the current signal is always positive with forward power flow and always negative with reverse power flow between the 73° and the 148° intervals of the voltage signal. (See for example U.S. Pat. No. 3,518,491.) This relationship is true for all power factors between 0.3 lagging and 0.85 leading. The reverse power flow detector of this invention samples the current during the 73° to 148° interval, determines its polatity and thus determines the direction of power flow in the monitored line. The reverse power flow detector will operate over the greatest range of power factors if the sampling is done at 90°.
Referring now to FIG. 1, the schematic diagram of the preferred form of this invention shows a reverse power flow detector which includes a voltage sampling circuit, generally indicated as 10, a current sampling circuit generally indicated as 12, a signal gate circuit indicated as 14 and an output circuit, indicated as 16. The voltage sampling circuit comprises a transformer 18 which is connected to the line 20 to be monitored. Transformer 18 isolates the voltage sampling circuit 10 and provides the voltage for the DC supply and the voltage sampling circuit. DC power for all stages of the reverse power flow detector is developed by means of a bridge rectifier 22, control resistor 24 and a filter capacitor 26 connected as shown to a secondary winding of the trannsformer 18.
The voltage sampling circuit 10 includes a voltage reference pulse generator 28, which is a unijunction transistor, for generating a voltage reference signal. The emitter 30 of unijunction transistor 28 is connected to the line 20 through another winding of transformer 18. One pulse per cycle is obtained from the unijunction transistor 28. The pulse is obtained during the half cycle when voltage of emitter 30 is positive with respect to the circuit ground. The time during the half cycle in which the pulse is obtained is determined by the time constant of the integrator circuit consisting of resistors 32, 34 and the capacitor 36. A second capacitor 38 may be connected in parallel relation with the resistor 32 to shift the phase of the voltage applied to emitter 30 of unijunction transistor 28. This makes it easier to obtain a voltage reference pulse at 90 degrees of the line voltage.
The pulse obtained from base one 40 of the unijunction transistor 28 is of very short duration, such as for example, 10 microseconds. The base two 42 of unijunction transistor 28 is preferably connected to the DC supply through a temperature compensating resistor 44. Since the DC supply is obtained through the same source as the emitter voltage, large variations can occur in the line voltage without affecting the phase angle at which the voltage reference pulse is generated. The voltage reference pulse is fed to SCR 46 through gate circuit 14. The operation of gate 14 will be more fully described as this description proceeds.
The current sampling circuit 12 includes a resistor 48 which develops the current signal. As shown, the resistor 48 is connected in the line 20 which is being monitored. However, as will be understood, if the line current in the monitored line 20 is too great, resistor 48 may be connected to the secondary of a current transformer which is mounted on the monitored line 20. A pair of semiconductor diodes 50, 52 are preferably connected in parallel relation about resistor 48, as shown, to limit the voltage developed across the resistor 48. As will be understood, the voltage developed across resistor 48 is in phase with the line current being monitored.
Voltage from resistor 48 is stepped up by a transformer 54 and then applied to the base 56 of a transistor 58. Transistor 58 and a second transistor 60 are arranged, as shown, as an emitter coupled binary circuit which will change the current signal wave form from sinusoidal to rectangular. Transistors 58 and 60 also serve to determine the minimum current level at which reverse flow may be detected or sensed.
As above noted, the voltage pulses from the pulse generators 28 are fed to the SCR 46, through gate 14. Gate 14 is controlled by the transistor 60. When no current, or forward current, is passing through the transformer 54, the polarity is such that transistor 58 turns off and transistor 60 turns on. The voltage pulses are thus shorted by transistor 60, and do not feed SCR 46. When the current reverses, the polarity of transformer 54 is such that transistor 58 turns on, turning off transistor 60. Gate 14 is thus opened, allowing the voltage pulses from pulse generator 28 to trigger SCR 46, for every positive portion of the cycle.
The pulsating voltage from SCR 46 is smoothed by resistor 62, capacitor 64 and is fed to the base 66 of transistor 68. This turns on transistor 68, thus energizing relay 70. Resistor 62, capacitor 64 and transistor 68 are provided to obtain a time delay of approximately 1 second to avoid unnecessary switching on short duration reverse power flow. Diode 72 is provided to assure resetting of SCR 46, while resistor 74 is provided to give a holding effect and prevent chattering of relay 70.
When relay 70 is energized it closes contact 76 and opens contact 78, thus energizing relay 80. This will latch the controls in a power reverse position, as will be explained with reference to FIG. 2. When forward power again flows, relay 70 is deenergized, opening contact 76 and closing contact 78 to energize relay 82 and deenergize relay 80. This will again place the controls in a power forward position.
In the preferred embodiment, a selector switch 84 is provided. Selector switch 84 is provided with 4 positions. In the first position contacts 84a are closed, placing the detector and control circuit in an automatic mode. When in the second position, contacts 84b are closed turning the circuit off. In the third position contacts 84c are closed applying energy through closed contact 86 of relay 82 to light bulb 88. This provides an indication that the circuit is operating correctly in the forward mode. When switched to the fourth position, contacts 84d are closed. This will cause contact 86 to open and contact 90 of relay 80 to close, applying energy to bulb 92. This will provide an indication that the circuit is operating properly in the reverse mode. Thus by means of the selector switch 84, test positions may be provided to allow testing of the circuit to ensure that it is operating properly.
Referring now to FIG. 2, there is shown the control circuit for use with an electrical device, such as, for example, a voltage regulator. As will be understood, when the power flow reverses it is necessary to switch the automatic control of the regulator to a potential transformer on the source side of such regulator. In FIG. 2, the regulator automatic control is indicated by box 100 and the potential transformer by 102. In normal forward power condition relay 82 is energized (FIG. 1) and its contact 104 is closed. This allows energy to flow through relay 106 maintaining its contact 108 closed allowing energy to flow to controls 100. Resistor 110 and capacitor 112 are provided to give a delayed response to the operation of relay 106.
When power flow reverses, relay 82 is deenergized and relay 80 is energized, as previously explained. This will cause contacts 104 to open and contact 114 of relay 80 to close. As will be understood, when contact 104 opens, it will arc and it would be undesirable to connect the potential transformer to it during arcing. The delayed response of relay 106 is provided so that its contact 116 will not close until the arcing in contact 104 is extinguished. Of course, it will be apparent, that when switching from reverse flow condition to forward flow condition, the same action of relay 106 will prevent contact 108 from closing until arcing is extinguished in contact 114.
While there has been shown and described the present preferred embodiment of the invention, it will be clear to those skilled in the art that various changes may be made in the circuit detail without departing from the scope of the invention. As will be apparent, an output indication to provide an indication of reverse flow may be provided by utilizing the signal from the transistor 68 or the SCR 46 to drive other circuitry than the relay coil 70. Thus it will be apparent that changes may be made without departing from the spirit and scope of this invention.
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A solid state, reverse power flow detector and control circuit which samples the line voltage and current, once each cycle. The voltage sampling circuit includes a pulse generator providing a voltage pulse of short duration at a given time or phase angle in each cycle. The voltage signals are applied to an SCR through a gate operated by the current signals. With forward or no current the voltage signals do not reach the SCR. When current reverses the voltage signals are allowed to trigger the SCR. The SCR turns on a transistor energizing a relay, after a brief delay. The relay acts to set the regulator or other device in power reverse condition. When current again is forward the relay is deenergized and the device returned to the power forward condition.
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BACKGROUND
[0001] 1. Technical Field The present disclosure relates to containers for plants, and in particular, retaining members for informational tags on planting pots.
[0002] 2. Description of Related Art
[0003] Planting pots are often provided with apertures, such as, for example, slots, formed on a portion of the pots, for use in retaining informational tags or labels. The informational tags or labels can be constructed of plastic, or other flexible material with at least some elastic deformation characteristics, to exert tension against a perimeter of the apertures within which the tag has been compressed. As such, the apertures can be designed to require that a portion of the tag is crimped or otherwise bent, to be placed into the aperture, after which, the elastic tendency of the tag places it under tension to bias the tag against the perimeter of the aperture, to retain the tag. In this manner, information on the tag can be easily affixed to a planting pot, and/or, removed from the planting pot. Many such conventional tags and aperture assemblies are inconvenient, and unreliable. Among other things, the tags may be difficult to insert, and may only loosely retain the tags.
BRIEF SUMMARY
[0004] Some embodiments of the present disclosure comprise a container having a retaining member for retaining an informational tag to the container. The retaining member can include an aperture and an inlet channel having an inlet opening opposite the aperture. The inlet channel can have an inwardly tapering sidewall that tapers inward from the inlet opening to join and terminate at a perimeter of the aperture. In some embodiments, the aperture is a non-linear elongated slot, and can be formed in a zigzagging configuration.
[0005] Some embodiments of the present disclosure comprise a method of retaining a tag on a container. The method can include inserting a tag into an inlet opening of a retaining member and pushing the tag through an inlet channel having an inwardly tapering sidewall, until the tag extends through an outlet aperture. The tag can be compressed by compressing lateral edges of the tag toward one another to extend the tag through the outlet aperture. Furthermore, the tag can be compressed by imparting two or more bends on the tag, with at least two of the bends being toward opposite directions relative to a planar surface of the tag.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a bottom perspective view of a plant container for some embodiments of the present disclosure, showing a tag placed within a retaining member formed on the container.
[0007] FIG. 1B is a front elevation view of an example tag, for use in some embodiments of the present disclosure.
[0008] FIG. 2 is a bottom perspective view of the plant container of FIG. 1 , with the tag removed from the retaining member.
[0009] FIG. 2B is an enlarged perspective view of the retaining member for the plant container of FIG. 2 .
[0010] FIG. 3 is a top plan view of the plant container of FIG. 2 .
[0011] FIG. 3B is an enlarged top plan view of the aperture of the retaining member, with a tag retained within the aperture.
DETAILED DESCRIPTION
[0012] In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments of this disclosure. However, upon reviewing this disclosure one skilled in the art will understand that the invention may be practiced without many of these details. In other instances, well-known or widely available structures associated with plant pots, or informational tags used on plant pots, have not been described in detail to avoid unnecessarily obscuring the descriptions of the embodiments of the present disclosure.
[0013] Various embodiments of the present disclosure are described herein for purposes of illustration, in the context of use with plant pots. However, as those skilled in the art will appreciate upon reviewing this disclosure, use with other types of containers may also be suitable.
[0014] In the present description, where used, the terms “about” and “consisting essentially of” mean ±20% of the indicated range, value, or structure, unless otherwise indicated. It should be understood that the terms “a” and “an” as used herein refer to “one or more” of the enumerated components. The use of the alternative (e.g., “or”) should be understood to mean either one, both, or any combination thereof of the alternatives, unless expressly stated otherwise. As used herein, the terms “include” and “comprise” are used synonymously, and those terms and variants thereof are intended to be construed in a non-limiting, open sense.
[0015] As shown in FIGS. 1-3B , some embodiments of the present disclosure comprise a container 2 for holding planting soil and one or more plants. The container 2 can comprising a bottom wall 12 , a vertical sidewall 6 extending upward from the bottom wall, and a top rim 4 , positioned at a top edge region of the vertical sidewall 6 . The rim 4 can extend laterally outward from the vertical sidewall 16 , surrounding the entire circumference of the top edge region of the vertical sidewall 16 , and can be reinforced by spaced apart support ribs 10 , the spaced apart support ribs 10 extending radially outward from the vertical sidewall 6 . In some embodiments, such as that illustrated, the rim 4 is annular in shape, and a vertical sidewall 6 is comprised of annular horizontal cross sections.
[0016] Referring to FIGS. 1-2B , in some embodiments, a retaining member 14 is formed on the rim 4 of the container 2 , accessible from a downward facing portion of the rim 4 .
[0017] As best seen in FIGS. 1 and 1B , the retaining member 14 can be used to retain an informational tag 8 , having text and/or graphical designs, printed thereon, by inserting a retaining strip 9 of the tag 8 , into an aperture 16 of the retaining member 14 . In some embodiments, the retaining strip 9 must be deformed to be placed within the aperture 16 . The tag 8 , including its retaining strip 9 , or only the retaining strip 9 , can be a sheet like material, comprised of a plastic, or any other material having at least some elastic deformation tendencies sufficient to allow the retaining strip 9 to exert biasing force against the inside wall of the aperture when the retaining strip 9 is crimped and pushed through the aperture 16 , to place the retaining strip 9 under tension against inside walls of the aperture, to thereby retain the tag 8 .
[0018] As shown in FIGS. 1 & 1B , in some embodiments, the retaining strip 9 extends upward from a top portion of the tag 8 , with respect to the orientation of textual information, so that the retaining strip 9 can be inserted in an upwardly direction, from below the rim 4 , into the retaining member 14 , with a main body portion 8 ′ of the tag 8 hanging below the retaining member 14 .
[0019] As best seen in FIGS. 2-3B , the retaining member 14 can comprise a non-linear, elongated aperture 16 (or slot like opening), opening on an upward facing wall 20 of the rim 4 , and an inlet channel 18 leading to the aperture 16 from below the aperture 16 . The inlet channel 18 can have an inlet opening 17 on a downward facing side of the rim 4 , with a laterally inwardly tapering sidewall 19 that extends upward toward the aperture 16 , with one or more portions of the inwardly tapering sidewall 19 , tapering laterally inward toward a perimeter of the aperture 16 and terminating at the aperture 16 .
[0020] As will be appreciated by those skilled in the art after reviewing the present disclosure, a user may insert a portion of a tag (e.g., a retainer strip 9 ) upward through the inlet opening 17 of the retaining member 14 , to be guided by the inwardly tapering sidewall 19 , through the aperture 16 . As the tag is pushed upward, the inwardly tapering sidewall 19 can cause the edges of the tag to be compressed laterally toward one another, to crimp the tag gradually to conform to a contour that can pass through the aperture 16 , before being pushed through the aperture 16 , as best seen in FIG. 3B (showing a top plan view of the aperture with retaining strip 9 pushed through the aperture).
[0021] The aperture 16 itself can be defined by a perimeter 16 ′ formed at the top wall of the rim 4 , with the aperture 16 zigzagging (or otherwise alternating in direction) across a face thereof, as best seen in FIG. 3B . When the tag (or portion thereof, such as the retaining strip 9 ), is pushed through the aperture 17 in crimped or compressed form, and conforming to the zigzag perimeter shape of the aperture 17 , the elastic characteristics of the tag cause it to exert tension on the inside perimeter 16 ′ of the aperture 17 , to removably retain the tag in the retaining member 14 .
[0022] Referring to FIG. 3B , in some embodiments, a length “L” of the elongated aperture is about 1.07 inches. In other embodiments, the length is about 1.07 centimeters. In other embodiments, the length is less than or greater than 1.07 inches, or 1.07 centimeters.
[0023] Length “L” is defined to represent the furthest distance between two perimeter points of the elongated aperture 16 . In some embodiments, the width W 1 , between two perimeter points of the elongated aperture is about 0.11 inches. In other embodiments, W 1 is greater than, or less than 0.11 inches. In some embodiments, the width W 2 , between two perimeter points of the elongated aperture is about 0.03 inches. In other embodiments, W 2 is greater than, or less than 0.03 inches. In other embodiments, the dimensions indicated above as inches, are instead, centimeters.
[0024] In some embodiments, the inwardly tapering sidewall extends vertically a distance that is equal to about one third of a length “L” of the elongated aperture 16 . In some embodiments, the inwardly tapering sidewall extends vertically a distance that is equal to about half of a length “L” of the elongated aperture 16 . In some embodiments, the inwardly tapering sidewall extends vertically a distance that is equal to about ¾ of a length “L” of the elongated aperture 16 . In other embodiments, the inwardly tapering sidewall extends vertically a distance that is greater than one third, one half, or ¾ of a length “L” of the elongated aperture. In other embodiments, the inwardly tapering sidewall extends vertically a distance that is less than one third, one half, or ¾ of a length “L” of the elongated aperture.
[0025] After reviewing the present disclosure, an individual of ordinary skill in the art will immediately appreciate that some details and features can be added, removed and/or changed without deviating from the spirit of the invention. Reference throughout this specification to “one embodiment,” “an embodiment,” or “some embodiments,” means that a particular feature, structure or characteristic described in connection with the embodiment(s) is included in at least one or some embodiment(s), but not necessarily all embodiments, such that the references do not necessarily refer to the same embodiment (s). Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.
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Methods and apparatus for retaining an informational tag to a container are provided. In some embodiments of the disclosure, a container is provided with a retaining member on a rim thereof. The retaining member can have in inlet opening, with an inlet channel having inwardly tapering walls that terminate at an outlet aperture. The outlet aperture can have a zigzagging configuration for compressing the tag.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a roller and cage assembly, and more particularly, to a roller and cage assembly having a favorable lubrication property and which is suitable for high-speed rotation.
2. Description of the Prior Art
Roller and cage assemblies that take advantage of the characteristics of having a small cross-sectional height and large load capacity were frequently used in the past for the connecting rods of motorcycle engines.
FIG. 1 shows a roller and cage assembly of the prior art. This roller and cage assembly is disclosed in Japanese Utility Model Laid-Open Publication No. 4-41115.
As shown in the drawing, this roller and cage assembly is composed of cage 1, in which a plurality of roughly cylindrically shaped pockets 1a are formed at equal intervals and parallel to the axial direction, and rollers 2, which are inserted into each of said pockets 1a.
Cage 1 forms two rings 1b, and bars 1c, which mutually couple both said rings 1b and demarcate said pockets 1a together with each of said rings 1b, into a single unit. One pair each of inner retaining projections 1g and outer retaining projections 1h are formed on both of the insides as well as on both of the outsides of both ends of these columns 1c. These inner retaining projections 1g and outer retaining projections 1h project so as to face pockets 1a, and as a result, rollers 2 are restricted from falling out of pockets 1a.
The above-mentioned inner retaining projections 1g and outer retaining projections 1h are formed by providing two each of caulking grooves 1i and 1j in both the inner and outer surfaces of bars 1c so as to extend in the circumferential direction. These caulking grooves 1i and 1j act as oil grooves resulting in efficient lubrication.
Recently, the rotating speeds of engines have tended to increase. In order to allow the roller and cage assembly of the prior art to be compatible with these increasing engine speeds, the lubricating property was improved by providing oil grooves like those described above to prevent wear and seizure. However, the rotating speeds at which the roller and cage assembly of the prior art was able to withstand were still not satisfactory. Thus, this is a problem that should be solved in terms of development of engines having even higher rotating speeds.
Furthermore, although the lubrication property increases if the number of concave portions acting as oil grooves is increased or their area is expanded, since the rigidity of the cage decreases proportionally thus preventing it from being used practically, this cannot be performed simply.
On the other hand, in the roller and cage assembly of the prior art, wear and seizure is suppressed by performing copper or silver plating in order to accommodate increasing engine speeds. Although roller and cage assemblies on which silver plating has been performed allow the obtaining of favorable high-speed rotation performance in comparison with those on which copper plating has been performed, the maximum rotating speed these roller and cage assemblies are able to withstand is roughly 13,000 rpm. When the rotating speed is increased beyond this point, the disadvantage results in which wear and seizure occur even if considerably large amounts of lubricating oil is supplied. In addition, plating treatment using silver results in high costs, and this is also a problem that should be solved in terms of engine development.
Moreover, the roller and cage assembly of the prior art generates remarkably high levels of heat during high-speed rotation. In addition, it is also considerably heavy. These are also problems that should be solved in terms of engine development.
SUMMARY OF THE INVENTION
In consideration of the above-mentioned disadvantages of the prior art, a first object of the present invention is to provide a roller and cage assembly that achieves improvement of the lubrication properties while maintaining or increasing rigidity.
In addition, a second object of the present invention is to provide an inexpensive roller and cage assembly that together with having high wear resistance, suppresses the generation of heat resulting from high-speed rotation.
Moreover, a third object of the present invention is to provide a roller and cage assembly that achieves suppression of generation of heat resulting from high-speed rotation as well as being lightweight.
In order to achieve the above-mentioned first object, the present invention consists of a roller and cage assembly comprising: a cage in which a plurality of bars are arranged in a row in the circumferential direction so as to demarcate a plurality of cylindrically shaped pockets in parallel in the axial direction; rollers that are inserted into each of said pockets; and, inner retaining projections and outer retaining projections that restrict said rollers from falling out to the inside and outside, which protrude so that a portion of said bars faces said pockets as a result of providing caulking grooves on the inner and outer surfaces of each of said bars extending in the circumferential direction; wherein, together with forming concave portions in the center of the above bars with respect to cage width so as to extend the width of a portion of said pockets on both sides in the circumferential direction, padding equivalent to lightening holes that are removed as a result of forming said concave portions is formed in the insides of said bars.
In addition, in order to achieve the above-mentioned second object, the present invention consists of a roller and cage assembly comprising: a cage in which a plurality of roughly cylindrically shaped pockets are formed in parallel in the axial direction; and, rollers that are inserted into each of said pockets; wherein, composite plated films are formed at prescribed sites consisting of the uniform dispersed coprecipitation of fine particles of fluororesin.
Moreover, in order to achieve the above-mentioned third object, the present invention consists of a roller and cage assembly comprising: a cage in which a plurality of roughly cylindrically shaped pockets are formed in parallel in the axial direction; and, rollers that are inserted into each of said pockets; wherein, said rollers are made of ceramics.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a roller and cage assembly of the prior art.
FIG. 2 is a perspective view of a first embodiment of the roller and cage assembly of the present invention.
FIG. 3 is an overhead view of a portion of the roller and cage assembly shown in FIG. 2.
FIG. 4 is a longitudinal cross-sectional view of the state in which a portion of the roller and cage assembly shown in FIG. 2 is severed along a surface that includes the axial direction.
FIG. 5 is a longitudinal cross-sectional view of the state in which a portion of the roller and cage assembly shown in FIG. 2 is severed along a surface perpendicular to the axial direction.
FIG. 6 is a longitudinal cross-sectional view of the state in which a portion of a second embodiment of the roller and cage assembly of the present invention is severed along a surface that contains the axial direction.
FIG. 7 is a perspective view of a third embodiment of the roller and cage assembly of the present invention.
FIG. 8 is an overhead view of a portion of the roller and cage assembly shown in FIG. 7.
FIG. 9 is longitudinal cross-sectional view of the state in which a portion of the roller and cage assembly shown in FIG. 7 is severed along a surface including the axial direction.
FIG. 10 is a longitudinal cross-sectional view of the state in which a portion of the roller and cage assembly shown in FIG. 7 is severed along a surface perpendicular to the axial direction.
FIG. 11 is an enlarged cross-sectional view of a portion of the roller and cage assembly shown in FIG. 7.
FIG. 12 is a longitudinal cross-sectional of the state in which a portion of a fourth embodiment of the roller and cage assembly of the present invention is severed along a surface including the axial direction.
FIG. 13 is a perspective view of a fifth embodiment of the roller and cage assembly of the present invention.
FIG. 14 is an overhead view of a portion of the roller and cage assembly shown in FIG. 13.
FIG. 15 is a longitudinal cross-sectional view of the state in which a portion of the roller and cage assembly shown in FIG. 13 is severed along a surface including the axial direction.
FIG. 16 is a longitudinal cross-sectional view of the state in which a portion of the roller and cage assembly shown in FIG. 13 is severed along a surface perpendicular to the axial direction.
FIG. 17 is a graph showing the data obtained by placing the roller and cage assembly shown in FIGS. 13 through 16 and the roller and cage assembly of the prior art on a fluctuating load bearing tester.
FIG. 18 is a longitudinal cross-sectional view of the state in which a portion of a sixth embodiment of the roller and cage assembly of the present invention is severed along a surface including the axial direction.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following provides an explanation of a first embodiment of the roller and cage assembly of the present invention with reference to the attached drawings.
As shown in FIGS. 2 through 5, said roller and cage assembly is composed of cage 11, in which a plurality of cylindrically shaped pockets 11a are formed at equal intervals in the circumferential direction and in parallel to the axial direction, and needle-shaped rollers 12 that are inserted into each of said pockets 11a. Furthermore, pockets 11a are formed so that their dimensions are slightly larger than the dimensions of rollers 12 with the exception of the dimensions between each retaining projection to be described later.
Cage 11 forms two (cage) rings 11b and a plurality of (cage) bars 11c, arranged in a row in the circumferential direction so as to mutually couple both said rings 11b and demarcate each of said pockets 11a, into a single unit. As is clear from FIGS. 4 and 5, bars 11c have thick-walled portions 11d, each connected to both rings 11b, and thin-walled portions 11e juxtaposed between said thick-walled portions 11d. Roughly U-shaped concave portion 11f is demarcated in the center of the inside of bar 11c by these thick-walled portions 11d and thin-walled portions 11e. Furthermore, thick-walled portions 11d and thin-walled portions 11e are also shown in FIG. 2. Said concave portion 11f is provided in the form of a so-called lightening hole for reducing the weight of cage 1, and extends further to the outside than the pitch circle diameter (P.C.D.) of roller 12, and is also formed shorter than the length of pocket 11a.
A pair of inner retaining projections 11g are formed on both sides in the vicinity of both ends of said bars 11c, namely in each of thick-walled portions 11d. In addition, a pair of outer retaining projections 11h are formed on the outside at sites corresponding to said inner retaining projections 11g. These inner retaining projections 11g and outer retaining projections 11h protrude so as to face inside pockets 11a, and the interval between corresponding retaining projections of neighboring (cage) bars 11c in the circumferential direction is set to be slightly smaller than the diameter of rollers 12. As a result, rollers 12 are retained and thereby restricted from falling out of pockets 11a.
The above-mentioned inner retaining projections 11g and outer retaining projections 11h are formed by providing caulking grooves 11i and 11j so as to extend in the circumferential direction in both the inner and outer surfaces of bars 11c. Thus, since each retaining projection is formed only by caulking processing, they facilitate volume production and can be fabricated inexpensively. In addition, since these caulking grooves 11i and 11j act as so-called oil grooves, efficient lubrication is performed.
As is clear from each of the drawings, concave portions 11k of a prescribed length are formed in both sides in the circumferential direction of each bar 11c, and more specifically, in both sides of thin-walled portions 11e at the center of said bars 11c with respect to cage width, so as to extend the width of a portion of said pockets 11a demarcated by said stays 11c. These concave portions 11k act as oil grooves together with said caulking grooves 11i and 11j. However, in order to maintain or increase the rigidity of thin-walled portions 11e, the width dimensions of which have become smaller as a result of forming lightening holes by providing these concave portions 11k, padding equivalent to these lightening holes is formed in the insides of said thin-walled portions 11e, and thickness t 1 (FIG. 4) of said thin-walled portions 11e is set slightly thicker. By providing this padding for thin-walled portions 11e in this manner, the section modulus of said thin-wailed portions in the radial direction, and thus their rigidity, is greatly increased. This is an effective means of increasing mechanical strength with respect to roller and cage assemblies bearing radial loads.
As described above, since a large number of oil grooves are provided, lubrication is adequately performed and seizure is prevented, thus making said roller and cage assembly suitable for high-speed rotation.
Furthermore, as is clear from FIG. 4, with respect to thick-walled portions 11d that compose bars 11c together with the above-mentioned thin-walled portions 11e, since their thickness t 2 is set larger to be equal to the thickness of rings 11b, together with this allowing their shape to be simplified as well as facilitating cutting processing to allow them to be fabricated inexpensively, the rigidity of bridges in the form of bars 11c is improved thus making caulking processing easier. Thus, the above-mentioned inner retaining projections 11g and outer retaining projections 11h can be formed with high precision, and the amount of their protrusion can be stabilized, thus allowing them to reliably retain rollers 12.
FIG. 5 shows said roller and cage assembly fitted onto shaft 15 and outer ring 16. When used in this manner, roller 12 makes contact with roller guiding surfaces formed on both sides of the above-mentioned thick-walled portion 11d. Roller 12 is then guided nearly over P.C.D., and dimensions are set so that it does not make contact with inner and outer retaining projections 11g and 11h. Moreover, dimensions are also set so that the traveling surface of outer ring 16 and the outer surface of cage 11 make contact before contact is made between the inner surface of cage 11 and shaft 15.
The following provides an explanation of a second embodiment of the roller and cage assembly of the present invention using FIG. 6. Furthermore, since said roller and cage assembly is composed in the same manner as the first embodiment of the roller and cage assembly shown in FIGS. 2 through 5 with the exception of those portions explained below, an overall explanation will be omitted here, with the explanation only focusing on the essential portions. In addition, the same reference numerals are used for those constituent members that are identical to the constituent members of the roller and cage assembly of the first embodiment.
As shown in the drawing, in this roller and cage assembly, concave portions 11m are formed extending in the axial direction in the inside of outer retaining projections 11h and in the outside of each (cage) bar 11c of cage 11. These concave portions 11m are formed over the entire width of bars 11c, and are connected with the above-mentioned pockets 11a. Depth e of said concave portions 11m is set at roughly 0.1-0.2 mm. These concave portions 11m also act as oil grooves to increase lubrication property, thus making it difficult for seizure and so forth to occur even in the case of high-speed rotation. In addition, as a result of providing said concave portions 11m, together with the surface area that makes contact with the inner diameter side of a connecting rod being decreased, the weight of the roller and cage assembly is further reduced.
The following provides an explanation of a third embodiment of the roller and cage assembly of the present invention with reference to the attached drawings.
As shown in FIGS. 7 through 10, said roller and cage assembly is composed of cage 21, in which a plurality of cylindrically shaped pockets 21a are formed at equal intervals in parallel and in the circumferential direction, and needle-shaped rollers 22 that are inserted into each of said pockets 21a. Furthermore, pockets 21a are formed so that their dimensions are slightly larger than the dimensions of rollers 22 with the exception of the dimensions between each of the retaining projections to be described later.
Cage 21 forms two (cage) rings 21b and (cage) bars 21c that mutually couple both said rings 21b and demarcate said pockets 11a together with said rings 21b, into a single unit. As is clear from FIGS. 9 and 10, bars 21c have thick-walled portions 21d, each connected to both rings 21b, and thin-walled portions 21e juxtapositioned between said thick-walled portions 21d. Roughly U-shaped concave portion 21f is demarcated on the inside of cage 21 by these thick-walled portions 21d and thin-walled portions 21e. Said concave portion 21f is provided in the form of a so-called lightening hole for reducing the weight of cage 21, and extends farther to the outside than the pitch circle diameter (P.C.D.) of roller 22.
Inner retaining projections 21g are formed on both sides of the inner surfaces in the vicinity of both ends of said bars 21c, namely in each of thick-walled portions 21d, while a pair of outer retaining projections 21h are formed on the outside at sites corresponding to said inner retaining projections 21g. These inner retaining projections 21g and outer retaining projections 21h protrude so as to face inside pockets 21a, and the interval between corresponding retaining projections of neighboring (cage) bars 21c in the circumferential direction is set to be slightly smaller than the diameter of rollers 22. As a result, rollers 22 are retained and thereby restricted from falling out of pockets 21a.
The above-mentioned inner retaining projections 21g and outer retaining projections 21h are formed by providing caulking grooves 21i and 21j so as to extend in the circumferential direction in both the inner and outer surfaces of bars 21c. Thus, since each retaining projection is formed only by caulking processing, they facilitate volume production and can be fabricated inexpensively. In addition, since these caulking grooves 21i and 21j act as so-called oil grooves, efficient lubrication is performed.
As is clear from each of the drawings, concave portions 21k of a prescribed length are formed in both sides of each bar 21c, and more specifically, in both sides of thin-walled portions 21e, so as to extend the width of a portion of said pockets 21a demarcated by said bars 21c. These concave portions 21k act as oil grooves together with said caulking grooves 21i and 21j. However, in order to maintain the rigidity of thin-walled portions 21e, the width dimensions of which have become smaller as a result of providing these concave portions 21k, the thickness t 1 (FIG. 9) of said thin-walled portions 21e is set slightly thicker.
As described above, since a large number of oil grooves are provided, lubrication is adequately performed and seizure is prevented, thus making said roller and cage assembly suitable for high-speed rotation.
Furthermore, as is clear from FIG. 9, with respect to thick-walled portions 21d that compose bars 21c together with the above-mentioned thin-walled portions 21e, since their thickness t 2 is set larger to be equal to the thickness of rings 21b, together with this allowing their shape to be simplified as well as facilitating cutting processing to allow them to be fabricated inexpensively, the rigidity of bridges in the form of bars 21c is improved thus making caulking processing easier. Thus, the above-mentioned inner retaining projections 21g and outer retaining projections 21h can be formed with high precision, and the amount of their protrusion can be stabilized, thus allowing them to reliably retain rollers 22.
FIG. 10 shows said roller and cage assembly fitted onto shaft 25 and outer ring 26. When used in this manner, roller 22 makes contact with roller guiding surfaces formed on both sides of the above-mentioned thick-walled portion 21d. Roller 22 is then guided nearly over P.C.D., and dimensions are set so that it does not make contact with inner and outer retaining projections 21g and 21h. Moreover, dimensions are also set so that the traveling surface of outer ring 26 and the outer surface of cage 21 make contact before contact is made between the inner surface of cage 21 and shaft 25.
In the above-mentioned roller and cage assembly, cage 21 is made of, for example, cemented steel (SCM415, STKM13 and so forth), while rollers 22 are fabricated using ball-bearing steel (SUJ2 and so forth).
As shown in FIG. 11, a composite plated film 31 is formed on the surface of base material 30 of cage 21 by plating treatment. Furthermore, FIG. 11 shows an enlarged view of actual dimensions. The thickness of composite plated film 31 is actually roughly 5 μm. This composite plated film 31 is formed by uniform dispersed coprecipitation of fine particles of fluororesin (ethylene tetrafluoride) in a matrix. In said drawing, the black dots represent the fine particles of fluororesin, while the white portion other than the black dots represents the matrix.
Table 1 shown below indicates the composition of the above-mentioned composite plated film 31. However, in this table, two types of compositions are shown, one having a high content of fluororesin (PTFE) (Type A) and one having a low content (Type B).
TABLE 1______________________________________ A. High-Content B. Low Content Type Type For non-sticking, For wear resistanceProperties low wear use and sliding use______________________________________Nickel (Ni) wt % 83-86 88-90Phosphorous (P) wt % 7.5-9 8-9.5Fluororesin (PTFE) 6-8.5 (20-25 vol %) 1.5-3 (5-10 vol %)wt %Fluororesin μm <1 <1particle sizeDensity g/cm.sup.3 6.4-6.8 7.3-7.6Hardness after 250-350 400-500plating HVHardness after 400-500 750-900heat treatment HV______________________________________
As is clear from the above table, the matrix of composite plated film 31 consists primarily of nickel (Ni: non-electrolytic), and contains phosphorous (P). Furthermore, although a composite plated film 31 having the composition shown in said table is commercially available under the name "Kanifron" (trade name: Nippon Kanizen Co., Ltd.), it goes without saying that various compositions of films can be applied provided that it is a composite plated film formed by dispersed coprecipitation of fluororesin particles. In addition, the nickel contained in the form of a matrix is not limited to that which is non-electrolytic, but electrolytic nickel may also be used. In addition, substances other than nickel can be used for the matrix of the composite plated film.
Moreover, said table also shows the hardness (Vicker's hardness: HV) of composite plated film 31 both before and after heat treatment. As is clear from those values, the hardness of the film after adding heat treatment is greater than before. However, with respect to this hardness, better results are obtained for type B than type A shown in the above table.
As described above, in the roller and cage assembly as claimed in the present invention, a composite plated film 31, composed of the dispersed coprecipitation of fine particles of fluororesin, is formed on the portion of cage 21 that makes sliding contact with rollers 22 as well as the portions of cage 21 that make sliding contact with other components in the form of shaft 25 and outer ring 26 that are to be assembled with it. Thus, the composite plated film containing fine particles of fluororesin has an excellent self-lubricating property, and together with having high wear resistance, is also able to suppress the temperature rise accompanying high-speed rotation to a low level. Thus, it is suitable for use in bearings equipped on the connecting rods and so forth of high-speed engines since it promotes long service life. In addition, since its self-lubricating property is large when also used as a general-purpose bearing, the above-mentioned effects are demonstrated even during relatively low levels of lubrication or in the absence of lubrication.
Seizure of roller and cage assemblies occurs due to the amount of heat produced by friction. A comparative test of breakdown pV values was conducted using a centrifugal load bearing tester for the roller and cage assembly on which plating treatment had been performed as claimed in the present invention, and a roller and cage assembly on which conventional silver plating of the same dimensions had been performed.
Here,
p: Contact pressure of the outer surface of the cage (N/cm 2 ) and,
V: Sliding velocity of the outer surface of the cage [m/s]
In the above-mentioned tester, the pV value was determined when the roller and cage assembly demonstrated seizure as the pV value was increased while maintaining the amount of lubricating oil supplied constant. As a result of this experiment, the roller and cage assembly having a composite plated film according to the present invention demonstrated roughly 1.9 times greater pV resistance (shown below) than the roller and cage assembly having conventional silver plating. Furthermore, this value is equivalent to the pV value on the inner surface of the cage in the case of a maximum rotating speed of n=16,000 rpm on an actual engine connecting rod.
pV=678(N/cm.sup.2 ·m/s)
Furthermore, in this case, each of the major dimensions of the roller and cage assembly used as the testpiece in the above-mentioned experiment were as shown below.
Fw: Inner contact diameter=22 mm
Ew: Outer contact diameter=29 mm
Bc: Cage width=17 mm
Dw: Roller diameter=3.5 mm
Lw: Roller length=13.8 mm
Z: No. of rollers=14
The above-mentioned composite plated film 31 can be formed less expensively in comparison with the conventional silver plated film, thus allowing reduced costs to be achieved. In addition, since the fluororesin particles contained in composite plated film 31 also demonstrates a cushioning action in addition to self-lubricating action, silencing effects are also obtained as a result.
The following provides an explanation of a fourth embodiment of the roller and cage assembly of the present invention, referring to FIG. 12. Furthermore, since said roller and cage assembly is composed in the same manner as the third embodiment of the roller and cage assembly shown in FIGS. 7 through 11 with the exception of those portions explained below, an overall explanation will be omitted here, with the explanation only focusing on the essential portions. In addition, the same reference numerals are used for those constituent members that are identical to the constituent members of the roller and cage assembly of the third embodiment.
As shown in the drawings, in this roller and cage assembly, concave portions 21m are formed extending in the axial direction in the inside of outer retaining projections 21h and in the outside of each (cage) bar 21c of cage 21. These concave portions 21m are formed over the entire width of bars 21c, and their depth is set to roughly 0.1-0.2 mm. These concave portions 21m also act as oil grooves to increase the lubrication property, thus making it difficult for seizure and so forth to occur even in the case of high-speed rotation. In addition, as a result of providing said concave portions 21m, together with the surface area that makes contact with the inner diameter side of a connecting rod being decreased, the weight of the roller and cage assembly is further reduced.
Furthermore, although composite plated film 31 is formed over the entire surface of cage 21 in each of the embodiments described above, it may also only be formed at those sites that are particularly susceptible to wear and so forth.
The following provides an explanation of a fifth embodiment of the roller and cage assembly of the present invention with reference to the attached drawings.
As shown in FIGS. 13 through 16, said roller and cage assembly is composed of cage 41, in which a plurality of cylindrically shaped pockets 41a are formed at equal intervals in the circumferential direction and in parallel in the axial direction, and needle-shaped rollers 42 that are inserted into each of said pockets 41a. Furthermore, pockets 41a are formed so that their dimensions are slightly larger than the dimensions of rollers 42 with the exception of the dimensions between each of the retaining projections to be described later.
Cage 41 forms two (cage) rings 41b and (cage) bars 41c, that mutually couple both said rings 41b and demarcate said pockets 41a together with said rings 41b, into a single unit. As is clear from FIGS. 15 and 16, bars 41c have thick-walled portions 41d, each connected to both rings 41b, and thin-walled portions 41e juxtaposed between said thick-walled portions 41d. Roughly U-shaped concave portion 41f is demarcated on the inside of cage 41 by these thick-walled portions 41d and thin-walled portions 41e. Furthermore, thick-walled portions 41d and thin-walled portions 41e are also shown in FIG. 13. Said concave portion 41f is provided in the form of a so-called lightening hole for reducing the weight of cage 41, and extends farther to the outside than the pitch circle diameter (P.C.D.) of roller 42.
Inner retaining projections 41g are formed on both sides of the inner surfaces in the vicinity of both ends of said bars 41c, namely in each of thick-walled portions 41d, while a pair of outer retaining projections 41h are formed on the outside at sites corresponding to said inner retaining projections 41g. These inner retaining projections 41g and outer retaining projections 41h protrude so as to face inside pockets 41a, and the interval between corresponding retaining projections of neighboring (cage) bars 41c in the circumferential direction is set to be slightly smaller than the diameter of rollers 42. As a result, rollers 42 are retained and thereby restricted from falling out of pockets 41a.
The above-mentioned inner retaining projections 41g and outer retaining projections 41h are formed by providing two each of caulking grooves 41i and 41j so as to extend in the circumferential direction in both the inner and outer surfaces of bars 41c. Thus, since each retaining projection is formed only by caulking processing, they facilitate volume production and can be fabricated inexpensively. In addition, since these caulking grooves 41i and 41j act as so-called oil grooves, efficient lubrication is performed.
As is clear from each of the drawings, concave portions 41k of a prescribed length are formed in both sides of each bar 41c, and more specifically, in both sides of thin-walled portions 41e, so as to extend the width of a portion of said pockets 41a demarcated by said bars 41c. These concave portions 41k act as oil grooves together with said caulking grooves 41i and 41j. However, in order to maintain the rigidity of thin-walled portions 41e, the width dimensions of which have become smaller as a result of providing these concave portions 41k, the thickness t 1 (FIG. 15) of said thin-walled portions 41e is set slightly thicker.
As described above, since a large number of oil grooves are provided, lubrication is adequately performed and seizure is prevented, thus making said roller and cage assembly suitable for high-speed rotation.
Furthermore, as is clear from FIG. 15, with respect to thick-walled portions 41d that compose bars 41c together with the above-mentioned thin-walled portions 41e, since their thickness t 2 is set larger to be equal to the thickness of rings 41b, together with this allowing their shape to be simplified as well as facilitating cutting processing to allow them to be fabricated inexpensively, the rigidity of bridges in the form of bars 41c is improved thus making caulking processing easier. Thus, the above-mentioned inner retaining projections 41g and outer retaining projections 41h can be formed with high precision, and the amount of their protrusion can be stabilized, thus allowing them to reliably retain rollers 42.
FIG. 16 shows said roller and cage assembly being used by fitting onto shaft 45 and outer ring 46. When used in this manner, roller 42 makes contact with roller guiding surfaces formed on both sides of the above-mentioned thick-walled portion 41d. Roller 42 is then guided nearly over P.C.D., and dimensions are set so that it does not make contact with inner and outer retaining projections 41g and 41h. Moreover, dimensions are also set so that the traveling surface of outer ring 46 and the outer surface of cage 41 make contact before contact is made between the inner surface of cage 41 and shaft 45.
In the above-mentioned roller and cage assembly, cage 41 is made of, for example, cemented steel (SCM415, STKM13 and so forth).
On the other hand, ceramics is employed for the material of each of rollers 42 equipped on said roller and cage assembly, and said ceramics is, for example, silicon nitride (Si 3 N 4 ).
Since the roller and cage assembly as claimed in the present invention is equipped with rollers made of ceramics, it was confirmed by the following experiment that the temperature rise accompanying its rotation is suppressed to a low level.
This experiment consisted of placing the roller and cage assembly as claimed in the present invention having the above-mentioned composition, and a conventional roller and cage assembly equipped with rollers made of ball-bearing steel in which the dimensions of each portion are equal to those of said roller and cage assembly, on a fluctuating load bearing tester under the same conditions. The temperature rises of both assemblies were then measured over time. Each of the roller and cage assemblies used as the testpieces in this experiment were both fabricated for use with engine connecting rods, and particularly as large end bearings. Each of the major dimensions shown in FIG. 15 are set as shown below. In addition, the roller and cage assemblies used had 14 rollers.
Fw: Inner contact diameter=22 mm
Ew: Outer contact diameter=29 mm
Bc: Cage width=17 mm
Furthermore, the experimental conditions were set as shown below.
Rotating speed: 5000 rpm
Load: ±1000 kgf
Lubrication: 1 liter/min (forced lubrication)
Temperature measurement site: Outer surface of the outer ring fit onto the outside of the roller and cage assembly (ball-bearing steel: SUJ2, external dimension: 40 mm)
The results of the above-mentioned experiment are shown in FIG. 17. In FIG. 17, solid line a indicates the measured values relating to the roller and cage assembly as claimed in the present invention, while broken line b indicates the measured values relating to the roller and cage assembly of the prior art. As shown in the graph, the maximum temperature measured for the roller and cage assembly as claimed in the present invention equipped with rollers made of ceramics was 68° C., while the maximum temperature measured for the roller and cage assembly of the prior art was 85° C., thus indicating that the roller and cage assembly as claimed in the present invention is able to significantly suppress temperature rise in comparison with the roller and cage assembly of the prior art.
As is clear from these results, the roller and cage assembly as claimed in the present invention is suitable for use during high-speed rotation such as for engine connecting rods.
In addition, in the case of ceramic rollers 42, if, for example, their diameter and length are 3.5 mm and 13.8 mm, respectively, their weight is only 0.42 g, thus achieving a weight reduction of 58% in comparison with ball-bearing steel rollers of the same dimensions weighing 1.01 g. Thus, the rotating portion equipped with said roller and cage assembly is lighter in weight, thus contributing to higher engine speed.
The following provides an explanation of a sixth embodiment of the roller and cage assembly of the present invention using FIG. 18. Furthermore, since said roller and cage assembly is composed in the same manner as the fifth embodiment of the roller and cage assembly shown in FIGS. 13 through 16 with the exception of those portions explained below, an overall explanation will be omitted here, with the explanation only focusing on the essential portions. In addition, the same reference numerals are used for those constituent members that are identical to the constituent members of the roller and cage assembly of the fifth embodiment.
As shown in the drawing, in this roller and cage assembly, concave portions 41m are formed extending in the axial direction in the inside of outer retaining projections 41h and in the outside of each (cage) bar 41c of cage 41. These concave portions 41m are formed over the entire width of bars 41c, and their depth is set to roughly 0.1-0.2 mm. These concave portions 41m also act as oil grooves to increase the lubrication property, thus making it difficult for seizure and so forth to occur even in the case of high-speed rotation. In addition, as a result of providing said concave portions 41m, together with the surface area that makes contact with the inner diameter side of a connecting rod being decreased, the weight of the roller and cage assembly is further reduced.
Furthermore, although silicon nitride is used for the ceramic material of rollers 42 in each of the above-mentioned embodiments, other ceramics may naturally also be applied corresponding to the application of the roller and cage assembly and the magnitude of the load to be borne.
As has been explained above, in the roller and cage assembly according to the present invention, since an improved lubrication property is achieved while maintaining or increasing rigidity, said roller and cage assembly is suitable for use as a bearing equipped on the connecting rod and so forth of a high-speed engine as a result of offering the advantage of long service life.
On the one hand, in the roller and cage assembly according to the present invention, since a composite plated film, containing fluororesin particles having excellent self-lubrication property, is formed at prescribed sites, together with said roller and cage assembly having high wear resistance during low levels of lubrication, the temperature rise accompanying rotation is suppressed to a low level, thus making said roller and cage assembly suitable for use as a bearing equipped on the connecting rod and so forth of high-speed engine as a result of offering the advantage of long service life.
In addition, since said composite plated film can be formed less expensively than the silver plating performed in the prior art, an additional advantage is offered in the form of reduced costs.
Moreover, since said fluororesin particles demonstrate a cushioning action in addition to self-lubricating action, silencing effects are also obtained.
On the other hand, in the roller and cage assembly according to the present invention, as a result of the rollers being made of ceramics, the temperature rise accompanying rotation is suppressed to a low level, thus allowing said roller and cage assembly to be suitable for use as a bearing equipped on a connecting rod, and particularly the large end, of high-speed engines.
In addition, since ceramic rollers are lighter in weight than other rollers made of ball-bearing steel and so forth, the weight of the entire roller and cage assembly can be reduced, thus offering the advantage of being suitable for use in high-speed rotating portions.
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Firstly, a roller and cage assembly is disclosed that achieves improved lubricating property while maintaining or increasing rigidity. While concave portions are formed so as to extend the width of the central portion of pockets to allow these to act as oil grooves, on the other hand, padding equivalent to lightening holes that are removed by providing said concave portions is performed in columns to obtain high rigidity.
Secondly, a roller and cage assembly is disclosed that together with being inexpensive and having high wear resistance, suppresses the generation of heat resulting from high-speed rotation. The above-mentioned effects are obtained by forming a composite plated film at prescribed sites by uniform dispersed coprecipitation of fine particles of fluororesin.
Thirdly, a roller and cage assembly is disclosed that together with suppressing the generation of heat resulting from high-speed rotation, also achieves light weight. The above-mentioned effects are obtained by using ceramic rollers.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser. No. 10/395,191 filed Mar. 25, 2003, which is a continuation of U.S. application Ser. No. 10/236,991 filed Sep. 5, 2002, which is a continuation of the U.S. National Stage of International Application No. PCT/EPO 1/03100 filed Mar. 20, 2001, the entire contents of all of which are expressly incorporated herein by reference thereto.
TECHNICAL FIELD
[0002] The present invention relates to a method of producing a beta-glucan; use of a non-pathogenic saprophytic filamentous fungus or composition comprising it for providing a beta-glucan and thereby improving food structure, texture, stability or a combination thereof; use of a non-pathogenic saprophytic filamentous fungus for providing a beta-glucan and thereby providing nutrition; and use of a fungus or composition comprising it in the manufacture of a medicament or nutritional composition for the prevention or treatment of an immune disorder, tumor or microbial infection.
BACKGROUND ART
[0003] Over the last decade there has been a great deal of interest in biopolymers from microbial origins in order to replace traditional plant- and animal derived gums in nutritional compositions. New biopolymers could lead to the development of materials with novel, desirable characteristics that could be more easily produced and purified. For this reason, the characterization of exopolysaccharide (“EPS”) production at a biochemical as well as at a genetic level has been studied. An advantage of EPS is that it can be secreted by food micro-organisms during fermentation, but using EPS produced by micro-organisms gives rise to the problem that the level of production is very low (50-500 mg/l) and that once the EPS is extracted it loses its texturing properties.
[0004] One example of an EPS is a beta-glucan. Beta-glucans are made of a β-glucose which are linked by 1-3 or 1-6 bonds and have the following characteristics that are attractive to processors in the food-industry: viscosifing, emulsifying, stabilising, cryoprotectant and immune-stimulating activities.
[0005] Remarkably, it has been found that fungi can produce high amounts of biopolymers (20 g/l) such as beta-glucans. One example is scleroglucan, a polysaccharide produced by certain filamentous fungi (e.g. Sclerotinia, Corticium, and Stromatina species) which, because of its physical characteristics, has been used as a lubricant and as a pressure-compensating material in oil drilling (Wang, Y., and B. Mc Neil. 1996. Scleroglucan. Critical Reviews in Biotechnology 16: 185-215).
[0006] Scleroglucan consists of a β(1-3) linked glucose backbone with different degrees of β(1-6) glucose side groups. The presence of these side groups increases the solubility and prevents triple helix formation that, by consequence, decreases its ability to form gels. The viscosity of scleroglucan solutions shows high tolerance to pH (pH 1-11), temperature (constant between 10-90° C.) and electrolyte change (e.g. 5% NaCl, 5% CaCl 2 ). Furthermore, its applications in the food industry for bodying, suspending, coating and gelling agents have been suggested and strong immune stimulatory, anti-tumor and anti-microbial activities have been reported (Kulicke, W.-M., A. I. Lettau, and H. Thielking. 1997, Correlation between immunological activity, molar mass, and molecular structure of different (1→3)-β-D-glucans. Carbohydr. Res. 297: 135-143).
[0007] As there is a need for these type materials in the food industry, they have been further investigated by the present inventors, and this invention now has identified unexpected benefits in food processing operations due to the use of these materials.
SUMMARY IF THE INVENTION
[0008] Remarkably, a class of filamentous fungi has now been identified and isolated which has been found to produce a fungal exopolysaccharide that exhibits characteristics that are attractive to the food industry. Two aspects of the EPS of interest are (a) its good texturing properties and (b) its ability to promote an immuno-stimulatory effect in in vitro and in vivo immunological assays. The fungal EPS could be incorporated into a health food (e.g., EPS as texturing fat replacer for low-calorie products or new immuno-stimulatory products) or provided alone for example as a food supplement.
[0009] Surprisingly, it has also been found that these fungi are able to produce a remarkably high yield of a beta-glucan.
[0010] Accordingly, in a first aspect, the present invention provides a method for producing a beta-glucan which comprises: fermenting a suspension comprising a non-pathogenic saprophytic filamentous fungus selected from the group consisting of Penicillium chermesinum, Penicillium ochrochloron, Rhizoctonia sp., Phoma sp., or a combination thereof in a minimal medium consisting essentially of glucose and salts; and extracting the beta-glucan from the fermented suspension.
[0011] Preferably, the fermentation is carried out for at least about 50 hours. The fermentation medium may additionally comprise a component selected from the group consisting of NaNO 3 , KH 2 PO 4 , MgSO 4 , KCl, and yeast extract, such that NaNO 3 (10 mM), KH 2 PO 4 (1.5 g/l), MgSO 4 (0.5 g/l), KCl (0.5 g/l), C 4 H 12 N 2 O 6 (10 mM), and glucose (60 g/l) are present in the fermentation medium. The pH of the medium may preferably be adjusted to a pH of 4.7.
[0012] According to one preferred embodiment, the fungi Penicillium chermesinum, Penicillium ochrochloron, Rhizoctonia sp. and Phoma sp. may be fermented together. The fermentation may be carried out for at least about 50 hours, and the medium may additionally comprise a component selected from the group consisting of NaNO 3 , KH 2 PO 4 , MgSO 4 , KCl, and yeast extract.
[0013] The present invention also provides for enhancing the structure, texture, or stability of a food product by adding an effective amount of the beta-glucan produced according to the present method to the food product. Similarly, the beta-glucan produced by the present method may be added to a nutritional composition to provide enhanced nutrition, or to a medicament for prevention or treatment of an immune disorder, tumor, or microbial infection.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] One or more of a non-pathogenic saprophytic filamentous fungus selected from the group consisting of Penicillium chermesinum, Penicillium ochrochloron, Rhizoctonia sp., Phoma sp., and combinations thereof is fermented to form the beta-glucan. Preferably, at least three of these fungi are fermented together. More preferably all of these fungi are fermented together.
[0015] The fermenting step is conducted for at least about 50 hours, preferably for about 80 hours to about 120 hours, and even more preferably for about 96 hours. These times are advantageous for obtaining high yields of beta-glucan.
[0016] The fermenting step is advantageously conducted in suspension in a medium comprising at least one component selected from the group consisting of NaNO 3 , KH 2 PO 4 , MgSO 4 , KCl and yeast extract. Preferably, at least two or three of these components are used and most preferably all these components are used together to provide the best yields of beta-glucan. Advantageously, the beta-glucan is added to a food product, a nutritional composition, or a medicament.
[0017] Preferably, the fungus is cultivated in a minimal medium. More preferably, the medium consists essentially of glucose and salts, and provides the advantage of enabling isolation of a highly pure polysaccharide at the expense of the production yield. This is because yeast extract contains polysaccharides that are difficult to separate from the EPS. Most preferably, the medium comprises NaNO 3 (10 mM), KH 2 PO 4 (1.5 g/l), MgSO 4 (0.5 g/1), KCl (0.5), C 4 H 12 N 2 O 6 (10 mM) glucose (60) and has a pH of 4.7.
[0018] The suitable fungus that can be used according to the invention includes those selected from the group consisting of Penicillium chermesinum, Penicillium ochrochloron, Rhizoctonia sp., Phoma sp., or a combination thereof.
[0019] Additional features and advantages of the present invention are described in, and will be apparent from the description of the most preferred embodiments which are set out below and in the examples.
[0020] In one preferred embodiment, beta-glucans are produced by fermenting a suspension which comprises a fungus in a medium of (g/l) NaNO 3 (3), KH 2 PO 4 (1), MgSO 4 (0.5), KCl (0.5), Yeast Extract (1.0), and glucose (30) with the pH of medium adjusted to 4.7. The fermentation is allowed to proceed for about 96 hours at about 28° C. with shaking at about 18 rpm. In an alternative embodiment, strains which initially do not appear to produce the polysaccharide are incubated for about 168 hours and then are added to the medium under the previously described conditions.
EXAMPLES
[0021] The following examples are given by way of illustration only and in no way should be construed as limiting the subject matter of the present application.
Example 1
Fungal Beta-Glucan Production
[0022] The following fungal isolates were isolated and classified:
Lab-isolate “Italian”, public name CBS identification P28 Penicillium chermesinum Penicillium glabrum (teleomorph*) P45 Penicillium ochrochloron Eupenicillium euglaucum (anamorph**) P82 Rhizoctonia sp. Botryosphaeria rhodina (teleomorph)/ Lasiodiplodia theobromae (anamorph) P98 Phoma sp. N/A VT13 Phoma sp. N/A VT14 Phoma sp. N/A **anamorph = asexual form, *teleomorph = sexual form N/A = not available.
Example 2
Standard Polysaccharide Production
[0023] Media TB1 (g/l) was used as follows: NaNO 3 (3), KH 2 PO 4 (1), MgSO 4 (0.5), KCl (0.5), Yeast Extract (1.0), and glucose (30) with the pH adjusted to 4.7.
[0024] The fermentation time was 96 h at 28° C. with shaking at 180 rpm. For strains which initially did not seem to produce any polysaccharide the incubation was prolonged to 168 h.
[0025] Results of polysaccharide production were as follows:
Specific Biomass Polysaccharide production Fungal strain (g/l) (g/l) pH (g/g) Slerotium glucanicum NRRL 3006 9.06 ± 2.06 11.20 ± 0.71 3.79 1.24 Botritis cinerea P3 2.64 ± 0.10 5.90 ± 0.57 4.35 2.23 Sclerotinia sclerotiorum P4 1.16 ± 0.16 1.61 ± 0.13 2.50 1.38 Fusarium culmorum P8 6.51 ± 1.05 0.82 ± 0.13 7.70 0.13 Not identified P9 5.43 ± 0.53 1.32 ± 0.02 4.00 0.24 Penicillium chermesinum P28 4.08 ± 1.17 0.68 ± 0.11 3.30 0.17 Penicillium ochrochloron P45 10.53 ± 2.87 0.45 ± 0.07 3.50 0.04 Fusarium sp. P58 8.60 ± 2.12 1.25 ± 0.35 7.44 0.15 Sclerotinia sclerotiorum P62 2.10 ± 0.00 0.86 ± 0.00 3.80 0.41 Sclerotinia sclerotiorum P63 4.08 ± 0.54 1.33 ± 0.04 3.30 0.33 Botritis fabae P65 19.70 ± 0.00 0.50 ± 0.00 4.94 0.03 Rhizoctonia fragariae P70 12.52 ± 0.40 1.55 ± 0.07 8.60 0.12 Colletotrichum acutatum P72 6.01 ± 0.89 1.05 ± 0.07 7.00 0.17 Pestalotia sp. P75 8.70 ± 0.28 1.90 ± 0.28 6.30 0.22 Colletotrichum sp. P80 12.00 ± 1.95 0.65 ± 0.07 6.50 0.05 Colletotrichum sp. P81 5.10 ± 0.71 0.80 ± 0.00 5.70 0.16 Rhizoctonia sp. P82 5.70 ± 0.28 8.90 ± 1.56 6.50 1.56 Acremonium sp. P83 4.69 ± 0.62 1.45 ± 0.07 7.20 0.31 Acremonium sp. P84 5.50 ± 0.00 1.30 ± 0.00 7.20 0.24 Acremonium sp. P86 3.90 ± 0.71 1.00 ± 0.14 5.85 0.26 Acremonium sp. P90 8.08 ± 0.01 0.73 ± 0.18 4.40 0.09 Not identified P91 10.50 ± 0.14 1.28 ± 0.31 6.83 0.12 Chaetomium sp. P94 8.30 ± 1.43 1.00 ± 0.28 7.40 0.12 Phoma herbarum P97 13.61 ± 2.34 0.98 ± 0.22 7.50 0.07 Phoma sp. P98 11.01 ± 1.07 2.89 ± 0.01 8.00 0.26 Phoma sp. P99 11.76 ± 1.66 0.66 ± 0.04 6.45 0.06 *Values are given at the time of maximum EPS production. Data are means of two independent experiments ± standard deviation.
Example 3
Optimized Polysaccharde Production
[0026] Polysaccharide production by Rhizoctonia sp. P82, Phoma sp. P98 and Penicillium chermesinum P28 were studied. The results were as follows:
[0027] A. Effect of Carbon Source Cultivated on TB 1:
Specific Biomass Polysaccharide production Carbon source** (g/l) (g/l) pH (g/g) I. EPS production by Rhizoctonia sp. P82 Glucose 3.74 ± 0.80 18.55 ± 0.57 5.48 4.96 Fructose 4.20 ± 0.58 21.10 ± 0.89 5.60 5.02 Galactose 4.21 ± 0.19 16.67 ± 1.20 6.52 3.96 Xylose 3.45 ± 0.53 15.94 ± 2.42 6.07 4.63 Sorbitol 5.19 ± 0.80 4.70 ± 0.21 6.16 0.91 Glycerol 5.25 ± 0.60 1.54 ± 0.42 6.15 0.29 Sucrose 4.03 ± 0.59 14.07 ± 0.64 5.61 3.49 Maltose 4.07 ± 0.32 12.22 ± 0.34 5.28 3.00 Lactose 4.63 ± 0.47 8.78 ± 0.59 6.34 1.90 Starch 5.77 ± 0.95 17.36 ± 0.69 6.26 3.01 II. EPS production by Phoma sp. P98. Glucose 11.99 ± 0.64 1.97 ± 1.22 7.31 0.16 Fructose 11.11 ± 0.76 1.22 ± 0.45 7.35 0.11 Galactose 10.35 ± 0.78 4.12 ± 0.03 7.44 0.40 Xylose 11.47 ± 1.40 2.57 ± 0.27 7.35 0.22 Sorbitol 11.17 ± 0.69 7.54 ± 1.10 7.10 0.68 Glycerol 11.00 ± 0.37 0.63 ± 0.05 7.29 0.06 Sucrose 12.93 ± 0.44 2.91 ± 0.55 7.36 0.23 Maltose 12.50 ± 0.18 2.65 ± 0.98 6.92 0.21 Lactose 9.77 ± 0.01 1.06 ± 0.14 7.05 0.11 Starch 13.51 ± 1.65 2.28 ± 0.11 7.43 0.17 III. EPS production by Penicillium chermesinum P28*. Glucose 11.69 ± 0.04 0.59 ± 0.13 3.51 0.05 Fructose 12.91 ± 1.20 0.46 ± 0.06 3.64 0.04 Galactose 8.64 ± 2.09 0.00 ± 0.00 5.23 0.00 Xylose 10.68 ± 0.06 0.41 ± 0.13 3.57 0.04 Sorbitol 8.58 ± 1.67 1.09 ± 0.01 5.07 0.13 Glycerol 13.06 ± 1.05 0.18 ± 0.04 3.57 0.01 Sucrose 13.11 ± 0.80 0.59 ± 0.11 3.44 0.05 Maltose 10.90 ± 1.11 0.61 ± 0.16 3.53 0.06 Lactose 9.38 ± 0.34 0.00 ± 0.00 4.69 0.00 Starch 9.92 ± 2.04 0.50 ± 0.05 3.58 0.05 *Values are given at the time of maximum EPS production. Data are means of three independent experiments ± standard deviation. **Carbon sources were added to the medium at 30 g/l.
[0028] B. Effect of Glucose Concentration Cultivated on TB1:
Biomass Polysaccharide Specific production (g/l) (g/l) pH (g/g) I. EPS production by Rhizoctonia sp. P82*. Glucose (g/l) 30 3.74 ± 0.80 18.55 ± 0.57 5.85 4.96 40 7.29 ± 0.42 21.40 ± 0.89 6.03 2.94 50 8.30 ± 0.74 30.20 ± 1.47 5.67 3.64 60 8.17 ± 1.34 35.26 ± 1.64 6.13 4.32 II. EPS production by Phoma sp. P98*. Sorbitol (g/l) 30 8.60 ± 0.88 5.78 ± 0.61 7.22 0.67 40 12.08 ± 0.71 8.76 ± 0.40 7.12 0.73 50 13.22 ± 1.43 10.70 ± 0.48 7.13 0.81 60 16.47 ± 0.21 13.11 ± 0.33 7.56 0.80 *Values are given at the time of maximum EPS production. Data are means of three independent experiments ± standard deviation.
[0029] Surprisingly, it can be seen from the results that increasing the concentration of the carbon source (glucose and sorbitol for Rhizoctonia sp. P82 and Phoma sp. P98, respectively), EPS production by both strains increased markedly (approx. 100% increase) reaching a maximum of 35.2 and 13.1 g/l, respectively.
[0030] C. Effect of Nitrogen Source Cultivated on TB1:
Specific Nitrogen Biomass Polysaccharide production source (g/l) (g/l) PH (g/g) I. EPS production by Rhizoctonia sp. P82.* NaNO 3 3.74 ± 0.80 18.55 ± 0.57 5.53 4.96 NH 4 NO 3 4.05 ± 0.29 13.07 ± 1.87 2.58 3.23 Urea 5.54 ± 0.35 21.20 ± 0.14 5.43 3.82 (NH 4 ) 2 HPO 4 3.09 ± 0.81 14.26 ± 0.52 2.44 4.61 (NH 4 ) 2 SO 4 2.39 ± 0.49 8.91 ± 0.58 2.23 3.73 II. EPS production by Phoma sp. P98* NaNO 3 11.46 ± 0.85 3.24 ± 0.63 7.22 0.28 NH 4 NO 3 6.12 ± 0.33 1.17 ± 0.43 2.33 0.19 Urea 8.09 ± 1.01 3.57 ± 0.97 6.18 0.44 (NH 4 ) 2 HPO 4 6.53 ± 0.44 0.00 ± 0.00 2.43 0.00 *Values are given at the time of maximum EPS production. Data are means of three independent experiments ± standard deviation.
[0031] Besides sodium nitrate, other nitrogen sources such as urea, ammonium nitrate, ammonium phosphate and ammonium sulphate were used. Remarkably, on urea, EPS production by Rhizoctonia sp. P82 and Phoma sp. P98 reached the same levels obtained on sodium nitrate.
Example 4
EPS Purification and Characterization
[0032] The EPSs produced by Rhizoctonia sp. P82, Phoma sp. P98 and Penicillium chermesinum P28 were purified. The polysaccharides were exclusively constituted of sugars, thus indicating suprisingly high levels of purity. Both thin layer chromatography (TLC) and gas chromatography (GC) analysis showed that the EPSs from Rhizoctonia sp. P82 and Phoma sp. P98 were constituted of glucose only. In contrast, that from P. chermesinum P28 was constituted of galactose with traces of glucose.
[0033] The molecular weights (MW) of the EPSs from Rhizoctonia sp. and Phoma sp., estimated by gel permeation chromatography using a 100×1 cm Sepharose CL4B gel (Sigma) column, were both approximately 2·10 6 Da.
[0034] Determination of the position of the glucosidic linkages in the EPSs from Rhizoctonia sp. P82 and Phoma sp. P98 was carried out by GCms and GC after methylation, total hydrolysis, reduction and acetylation. The main products were identified by GCms analysis as glucitol 2,4-di-O-methyl-tetracetylated, glucitol 2,4,6-tri-O-methyl-triacetylated and glucitol 2,3,4,6-tetra-O-methyl-diacetylated indicating that both EPSs were characterised by monosaccharides linked with β-1,3 and β-1,6 linkages. In the case of the EPS from Phoma sp., the GC analyses showed three peaks in a quantitative ratio typical of a glucan with many branches; besides the above reaction products, the same type of analysis showed that the EPS from Rhizoctonia sp. gave rise to other reaction products such as penta- and esa-O-methyl-acetylated compounds which clearly indicated an uncompleted methylation.
[0035] Surprisingly, NMR analysis confirmed that both polysaccharides were pure, constituted of glucose only and characterized by β-1,3 and β-1,6 linkages.
Example 5
EPS Immuno-Stimulatory Effects
[0036] The EPSs from Rhizoctonia sp. P82 and Phoma sp. P98 were subjected to in vitro and in vivo experiments. A purified scleroglucan, obtained from S. glucanicum NRRL 3006, was used as a control. The purified EPSs were randomly broken in fragments of different molecular weights (from 1·10 6 to 1·10 4 Da) by sonication. The free glucose concentrations of the sonicated samples did not increase, thus indicating that no branches were broken. The experiments were carried out with EPSs at high MW (HMW, the native EPSs), medium MW (MMW, around 5·10 5 Da) and low MW (LMW, around 5·10 4 Da).
[0037] Immuno-stimulatory action was evaluated in vitro by determining effect on TNF-α production, phagocytosis induction, lymphocytes proliferation and IL-2 production.
[0038] All the EPSs stimulated monocytes to produce TNF-a factor; its content increased with increased polysaccharide concentration and was maximum when medium and low MWs were used.
[0039] In order to assess the effect of the EPSs on phagocytosis, two methods (Phagotest and Microfluoimetric Phagocytosis Assay) were used. The results gave a good indication that a high concentration of EPS improves phagocytosis.
[0040] In contrast, no significant effects were observed on lymphocyte proliferation and IL-2 production when the EPSs were added either alone or in combination with phytohemagglutinin (PHA). In addition, no cytotoxic effects were observed.
[0041] An in vivo study was carried out to assess immuno-stimulatory activity of the EPS using MMW (around 5·10 5 Da) glucan from Rhizoctonia sp. P82.
[0042] Female mice were inoculated three times subcutaneously (SC) and/or orally (OR) with MMW EPS (2 mg/100 g weight) and Lactobacillus acidophilus (1·10 8 cells/100 g weight) after 1, 8 and 28 days. Bleedings were carried out after 13 and 33 days. In vivo immuno-stimulation was evaluated by comparing antibody production by an ELISA test.
[0043] All the mice that received OR bacteria (groups 3, 4 and 5) showed no increase in their antibody content, regardless of their glucan inoculation. However, differences in antibody production were observed among mice inoculated SC with bacteria. Furthermore, antibody levels of mice that received SC only bacteria were significantly higher (P<0.01, by Tukey Test) than those that had received glucan and bacteria both SC and glucan OR and bacteria SC.
[0044] Interestingly, the results indicate that the EPS from Rhizoctonia sp. Gives rise to a decrease in antibody concentration. Remarkably, it can be concluded from this that the glucan from Rhizoctonia sp. causes activation of an antimicrobial activity of monocytes (see the effects described above relating to TNF-α production and phagocytosis induction) with a consequent reduction in the bacterial number leading, in turn, to a consistent reduction in antibody production.
[0045] In conclusion, the three filamentous fungi Rhizoctonia sp. P82, Phoma sp. P98 and Penicillium chermesinum P28 have a surprisingly good ability to produce extracellular polysaccharides of potential interest. In particular, Rhizoctonia sp. P82 is interesting in view of its short time required for fermentation, its high level of EPS production and its absence of β-glucanase activity during the EPS production phase. Furthermore, its EPS, as well as that from Phoma sp. P98, is a glucan characterised by β-1,3 and β-1,6 linkages. In addition, results relating to immuno-stimulatory effects of the glucan produced by Rhizoctonia sp. P82 indicate the possibility of a good stimulatory activity.
[0046] It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
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A method for producing a beta-glucan from a non-pathogenic saprophytic filamentous fuingus or composition that contains it. Also, methods for providing this beta-glucan in a food product to improve structure, texture, stability or combinations thereof, in a food product to provide nutrition or in the manufacture of a medicament or nutritional composition for the prevention or treatment of an immune disorder, tumor or microbial infection.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the priority benefit of U.S. Provisional Applications No. 60/869,163 titled HIGH PERFORMANCE DUAL-ENERGY IMAGING WITH A FLAT-PANEL DETECTOR: IMAGING PHYSICAL FROM BLACKBOARD TO BENCHTOP TO BEDSIDE filed Dec. 8, 2006 in the names of VanMetter et al. and U.S. Provisional Applications No. 60/889,365 titled DEVELOPMENT AND IMPLEMENTATION OF A HIGH-PERFORMANCE CARDIAC-GATED DUAL-ENERGY IMAGING SYSTEM filed Feb. 12, 2007 in the names of VanMetter et al, both of which are incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates generally to the field of projection radiography and in particular to the acquisition of multiple-energy projection radiographic images. More specifically, the invention relates to a method of cardiac gating for multiple-energy imaging that mitigates artifacts resulting from cardiac motion.
BACKGROUND OF THE INVENTION
In multiple-energy projection radiographic imaging, a number of images of the same object are acquired that reveal the x-ray transmittance of the object for differing x-ray spectra. The images are acquired sequentially through the use of an x-ray detector. The images can be decomposed to produce material specific images, such as tissue-only and bone-only images.
Radiographic imaging procedures that require multiple exposures, such as dual-energy imaging, acquire multiple images over a period of time, which may include different stages of the cardiac cycle. The different stages of the cardiac cycle are associated with motion of the heart and the arterial vessels. As such, the relative anatomical motion of the heart and the arterial vessels between the acquired images gives rise to artifacts in the reconstructed image. Anatomical motion and the resulting artifacts can be avoided by timing the image acquisition to occur only during a particular stage of the cardiac cycle, for example diastole when heart motion is minimal. This is commonly referred to as “cardiac gating”.
Electro-cardio-graph (ECG) signals have been used as a method of cardiac gating. ECG, however, requires that electrical contact be made to the patient's skin by means of adhesive pads with attached electronic wires. The electrical contacts are normally attached to areas of the chest. The conductive pads are radio-opaque and can occlude diagnostically important areas of the patient's anatomy. The use of ECG for cardiac gating also requires time consuming preparation of the attachment site, uncomfortable removal of the conductive pads, and the expense and inconvenience of disposable contact pads.
Therefore, there is a need to provide a more convenient and efficient method of cardiac gating for dual-energy imaging that will not occlude the x-ray beam.
SUMMARY OF THE INVENTION
The present invention provides alternative methods of cardiac gating for projection radiographic imaging. Both methods comprise measuring the duration of the patient's cardiac cycle. The measurement of the duration of the patient's cardiac cycle can be performed using an apparatus that measures peripheral blood perfusion, such as a pulse oximeter. A pulse oximeter reports the percentage of arterial oxygen, computed through absorption characteristics of oxygenated hemoglobin and deoxygenated hemoglobin. The duration of the patient's cardiac cycle can be averaged over a fixed number of cycles to estimate the patient's instantaneous heart rate.
The cardiac cycle can be reduced into two distinct mechanical periods: diastole and systole. As the patient's heart rate changes, the proportion of time that the heart spends within each phase is affected. Lasting for approximately 0.6 seconds in an average person having a heart rate of 67 beats per minute, diastole encompasses the quiescent phase of the heart where blood flows passively from the atria into the ventricles. Systole lasts approximately 0.3 seconds in an average person and is the largest contributor to cardiac motion within the cardiac cycle.
Both methods include determining whether the duration of patient's cardiac cycle provides adequate time to acquire the image during the diastole region of the current cardiac cycle. The determination of whether there is adequate time to acquire the image during the diastole region of the current cardiac cycle is dependent on the duration of the patient's cardiac cycle, physiological and system-component delays in the pulse oximeter, and the maximum delay in the imaging system.
In the event that the duration of the patient's cardiac cycle is sufficient, one example method includes triggering the imaging system to acquire the image during the diastole region of the current cardiac cycle. In the event that the duration of the patient's cardiac cycle does not meet the threshold requirement, a second example method includes implementing a delay that delays acquisition into the diastole period of the subsequent cardiac cycle. The delay can be implemented utilizing either hardware or software. The second method further includes triggering the imaging system to acquire the image during the subsequent diastole region of the patient's cardiac cycle.
Both methods can be designed to acquire images at a fixed point during the diastole period of the patient's cardiac cycle, such as the mid-point of the cardiac cycle. Both methods can be further designed to acquire images during a specific sub-phase of the diastole period.
The present invention provides a method of cardiac gating for multiple-energy imaging that allows for accurate image acquisition during the diastole period of the cardiac cycle while avoiding occlusion of diagnostically important areas of the anatomy. The present invention also provides a more convenient and efficient means of acquiring cardiac cycle information for use in cardiac gating.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of the embodiments of the invention.
FIG. 1 shows a logic flow diagram illustrating a method of cardiac gating for multiple-energy imaging in accordance with an embodiment of the present invention.
FIG. 2 shows a sample graph displaying the signal results for a patient monitored simultaneously using an ECG and a pulse oximeter.
FIG. 3 shows experimental results for a dual-energy exposure where both the first exposure and the second exposure are triggered during the current diastole period.
FIG. 4 shows experimental results for a dual-energy exposure where both the first exposure and the second exposure are triggered following an implemented delay during a subsequent diastole period.
DETAILED DESCRIPTION OF THE INVENTION
In the following description dual-energy imaging is described to illustrate an embodiment of the present invention. The present invention may also be applied to the acquisition of multiple-energy projection radiographic images. Each projection radiographic image of the multiple-energy projection radiographic images may be of the same or different energy level. For example, when three projection radiographic images are generated two projection radiographic images may be of the same energy level and the third projection radiographic image may be of a different energy level. Also, the use of a pulse oximeter is described to illustrate an embodiment of the invention. The present invention may also be performed using alternative devices that measure peripheral blood perfusion.
Referring now to FIG. 1 , a logic flow diagram illustrating a method of cardiac gating for dual-energy projection radiographic image acquisition in accordance with an embodiment of the present invention is shown.
In step 100 , a patient is oriented within the imaging system. In step 110 , a pulse oximeter is attached to the patient's finger. In step 115 the operator asserts a request to acquire an x-ray exposure.
In step 120 , the duration of the patient's cardiac cycle is measured using the pulse oximeter. The pulse oximeter features signal processing firmware that generates both an oximeter signal (plethysmogram) as well as a digital trigger pulse. Although the pulse oximeter does not directly measure heart movement, the oximeter can be calibrated to effectively determine the duration and location within the cardiac phase. In order to calibrate the oximeter physiological and system component delays must be quantified. The most important and largest delay is the time required for blood propagation through the patient's vasculature, for example from the left ventricle to the left index finger. This temporal delay, combined with delays associated with internal processing of the oximeter itself, offsets the plethysmogram and the digital trigger from the true motion of the heart.
The pulse oximeter can be calibrated to predict heart motion by monitoring a patient's heart rate simultaneously using an ECG and a pulse oximeter. Calibration of the pulse oximeter will now be described with reference to FIG. 2 . FIG. 2 depicts a sample graph displaying the signal results for a patient monitored simultaneously using an ECG and a pulse oximeter. In the ECG trace 200 the QT interval 210 is defined as systole. The QRS complex 220 can be used to predict the start of systole. The delay between the QRS complex 220 and various temporal landmarks in the plethysmogram 230 can be determined. The delay between the QRS complex 220 and the digital trigger 240 can also be determined. These delays have been found to be stable across both heart-rate and age. The delay between the ECG signal and the mechanical event of the start of systole must also be taken into account to determine the true delay between the start of systole and the digital trigger. This delay is physiological and has been experimentally determined to be approximately 50 ms.
Referring again to FIG. 1 , in step 130 , the duration of the patient's cardiac cycle, as determined by the plethysmogram, is averaged over a fixed number of cycles to estimate the patient's instantaneous heart rate. The proportion of the time that the heart spends within each phase of the cardiac cycle is affected by the patient's heart rate. Knowledge of the patient's heart rate and an indicator of the relative timing position within the cycle allow for predictions of the duration of diastole and the time at which the subsequent systole will end, thereby providing an accurate indicator of when the subsequent diastole period will begin.
In step 140 , a determination is made whether the duration of patient's cardiac cycle provides adequate time to acquire the image during the diastole region of the current cardiac cycle. The determination of whether there is adequate time to acquire the image during the diastole region of the current cardiac cycle is dependent on the duration of the patient's cardiac cycle, the delay between the start of systole and the digital trigger and the maximum delay in the imaging system.
Imaging systems are affected by internal delays, inherent in each individual imaging system, which act in combination and can influence the timing of image acquisition relative to an arbitrary timing signal, such as the beginning of the diastole period. The imaging system delays can be divided into two categories; delays that affect single image acquisition and delays that occur between dual-energy exposures. Examples of intra-exposure delays include: the time required for the software to assert a request for exposure after an input timing signal is provided, the time required for grid motion to begin and be confirmed after a software request for grid motion is asserted, the time required for the detector to assert an exposure request to the x-ray generator after it receives a software request for exposure, and the time required for the generator to produce an x-ray pulse after it has been requested by the detector. Examples of inter-exposure delays include: the time required for the generator to switch energy levels after a software request is asserted, the time required for the filter wheel to rotate after a software request is asserted, and the time required to transfer image data from the previous exposure from the detector to temporary storage and for the detector to be in a ready state, capable of responding to a software request for exposure.
The delays in the imaging system can be characterized by a fixed component and a variable component. These delays are inherent in the imaging system. The maximum and minimum delays of the imaging system, t max FPD and t min FPD , respectively, can be experimentally determined.
Given the delays in both the cardiac cycle monitoring using a pulse oximeter and the imaging system, correct timing of the x-ray exposure can be assured by using selectively implemented delays in either software or hardware. Both the timing and the duration that the heart spends in diastole are dependent upon the patient's heart rate. Assuring that the x-ray exposure falls within the limits of the diastole period is an important problem, which is confounded by the interdependent delays caused by each of the system components. These considerations make it necessary to provide two methods to trigger a cardiac gated exposure: within the diastole region of the current cardiac cycle or within the diastole region of a subsequent cardiac cycle. While it is always desirable to trigger each acquisition with the current diastole, the length and variability of the delays inherent in the imaging system can preclude that option.
There is adequate time to acquire the image during the diastole period of the current cardiac cycle if the following inequality is satisfied:
[ t HR ( HR )− t trigger ]>[t max FPD +t buffer ]
wherein t HR (HR) represents the duration of the patient's cardiac cycle, t trigger represents the delay between the start of systole and the digital trigger, t max FPD represents the maximum delay in the imaging system and t buffer represents a buffer period used to account for x-ray duration and a designed safety margin.
As indicated in decision block 140 , if the inequality is satisfied the software asserts an exposure request in step 145 . In step 150 the exposure is triggered during the diastole period of the current cardiac cycle. In step 152 the x-ray is acquired by the imaging system. In step 155 the system configures itself to obtain additional exposures. The process is then repeated from step 120 to acquire additional exposures. FIG. 3 depicts experimental results for a dual-energy exposure where both the first exposure 300 and the second exposure 310 are triggered in response to digital triggers 302 and 312 , respectively. The patient's heart rate 320 , as measured by the plethysmogram, provides adequate time to trigger the x-ray exposure during the diastole period of the current cardiac cycle based upon the delays inherent in the oximeter and the imaging system. As such, both exposures are triggered during diastole periods 304 and 314 , which occur during the current cardiac cycle. The patient's instantaneous heart rate 322 is determined by averaging the plethysmogram measured heart rate 320 over several cardiac cycles.
Referring again to FIG. 1 , if the inequality is not satisfied, a delay is implemented in step 160 to acquire the image in the diastole period of the subsequent cardiac cycle. The implemented delay is provided by the following equation:
t imp =[t HR ( HR )− t trigger ]+[t systole ( HR )− t min FPD ]+x[t diastole ( HR )−( t max FPD −t min FPD )]
wherein t imp is the required implemented delay, t HR (HR) represents the duration of the patient's cardiac cycle, t trigger represents the delay between the start of systole and the digital trigger, t systole (HR) and t diastole (HR) represent the duration of systole and diastole, respectively, and t max FPD and t min FPD are the maximum and minimum delay of the system, respectively. The x term represents a variable that is used to determine a fixed-point in the diastole period in which the exposure is obtained. For example, for x=½ the exposure is acquired at the mid-point of the diastole period. The variable term can be adjusted to acquire the image at a specific sub-phase of the diastole period.
In step 165 the software asserts an exposure request. In step 170 , the exposure is triggered during the diastole period of the subsequent cardiac cycle. In step 172 the x-ray is acquired by the imaging system. In step 175 the system configures itself to obtain additional exposures. The method is then repeated from step 120 to acquire additional exposures. FIG. 4 depicts experimental results for a dual-energy exposure where both the first exposure 400 and the second exposure 410 are triggered in response to digital triggers 402 and 412 , respectively. The patient's heart rate 420 , as measured by the plethysmogram, did not provide adequate time to trigger the x-ray exposure during the diastole period of the current cardiac cycle based upon the delays inherent in the oximeter and the imaging system. As such, a delay was implemented such that both exposures are triggered during diastole periods 404 and 414 , which occur during the subsequent current cardiac cycle. The patient's instantaneous heart rate 422 is determined by averaging the plethysmogram measured heart rate 420 over several cardiac cycles.
The invention has been described in detail with particular reference to a presently preferred embodiment, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.
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Methods are provided for cardiac gating of multiple-energy projection radiographic imaging utilizing an apparatus that measures the patient's peripheral blood perfusion. The choice of methods is dependant on the patient's heart rate and the delays inherent in the imaging system. A first method allows for imaging during the diastole period of the current cardiac cycle. A second method provides an implemented delay to acquire the image during the diastole period of a subsequent cardiac cycle. The use of the apparatus that measures the patient's peripheral blood perfusion allows for an efficient and convenient means of cardiac gating while avoiding occlusion of diagnostically important anatomy.
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REFERENCE TO RELATED APPLICATION
This application is related to Ser. No. 08/172,184, filed Dec. 23, 1993, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a moving ornament. More specifically, it relates to a rotating ornament suitable for mounting on an electric light bulb. The ornament is rotated by the heat energy normally wasted by the associated light bulb. This heat energy warms the air surrounding the bulb and creates convective air currents in a well known manner. My invention utilizes these air currents to spin a decorative lamp shade. The broad fields of architecture and advertising are seen as having potential applications for this improved ornament invention, as well as the more obvious field of consumer holiday decoration.
Thus it can be seen that the potential fields of use for this invention are myriad and the particular preferred embodiment described herein is in no way meant to limit the use of the invention to the particular field chosen for exposition of the details of the invention.
A comprehensive listing of all the possible fields to which this invention may be applied is limited only by the imagination and is therefore not provided herein. Some of the more obvious applications are mentioned herein in the interest of providing a full and complete disclosure of the unique properties of this previously unknown general purpose article of manufacture. It is to be understood from the outset that the scope of this invention is not limited to these fields or to the specific examples of potential uses presented hereinafter.
2. Description of the Prior Art
Devices for providing decorative lighting and lamp shades are old and well known in the art. The integration of movement into such lighting is also common. Phased multiple light advertising signs are examples of creating the appearance of movement in a lighted device without actually moving anything. Some startling and dramatic displays have been built using phased multiple neon tubing. Many examples of lamp shades may be found in which a static decorative ornamental appearance may be imbued upon a bare light bulb. However, the examples of providing dynamic lighting features by the provision of a moving lamp shade are rare although some moving lamp shades have been developed. In accordance with conventional terminology, the term lamp shade used herein may be taken to mean any transparent, translucent, or opaque material arranged between the eyes of a viewer and a light source so as to provide a change in the perceived light. The following known prior art has been directed to providing some sort of moving display which is associated with a light source. As will be seen, improvements and effectiveness of my invention are not rivaled in the prior art.
U.K. Pat. No. 527,240, dated Oct. 4, 1940, the applicants being Platers & Stampers, Ltd., describes a shade suitable for mounting on a lamp bulb and being convection driven while mounted thereon. The shade is balanced upon a stationary pin projecting upwardly from the bulb. By contrast, in my invention, the pin is part of the shade, and projects downwardly to be seated in a bearing. The novel arrangement both changes dynamic performance characteristics of the shade and also has safety implications related to the retracted location of the sharp pin.
The subject device of the U.K. patent also engages the light bulb in a manner which tends to insulate the engaged portion of the bulb. Ensuing concentration of heat may affect the life of the support, which is paper or an equivalent material. By contrast, the present invention is designed to engage the bulb more effectively with no more contact area. Whereas the support of the U.K. device surrounds the entire upper part of the bulb, the novel device partially surrounds a light bulb by coiling a wire around the bulb.
A significant degree of support is derived from coils spaced apart from adjacent coils. There is less insulating effect possible with the novel device, and consequently potentially less heat build up to reduce the life of the device. The coiled wire also enables a bearing to be readily installed and removed. This enables both ready insertion of the bearing during initial assembly and replacement, if the latter should be desired. A comparable bearing in the U.K. device is much harder to replace.
U.S. Pat. No. 3,435,201, issued to Kemenczky on Mar. 25, 1969, shows a heat-rotated illuminated ornament. The ornament requires a special incandescent bulb shield with a bearing dimple formed therein for its operation, or alternatively, requires that a comparable dimple be formed in an external support mounted to the bulb. In addition, the Kemenczky device requires this external support frame to maintain verticality. By contrast, the device of the instant invention is immediately attachable to a variety of commonly existing bulbs and requires no external support frame.
U.S. Pat. No. 3,263,353, issued to John P. Quinn on Aug. 2 1966, describes a rotatable lamp shade propelled by convective currents. Quinn's rotatable member is supported on an upwardly directed pin formed integrally with a wire having a coiled section for engaging the bulb of a lamp. By contrast, the present invention anchors a member corresponding to the pin in the rotated member, and downwardly oriented, so that it is partially obscured within the rotated member.
U.S. Pat. No. 2,511,394, issued to Wynnyk on Jun. 13, 1950, shows a decorative attachment for a lamp shade. The attachment is made to rotate by convective heat currents created by a light bulb similar to my device. However, my device forms the actual lamp shade and not a superficial attachment in addition to a lamp shade as is taught by Wynnyk. This seemingly insignificant difference leads to major structural and esthetic advantages for my arrangement which will be more fully developed later. In addition, the Wynnyk device requires an external support frame around the outside of the rotating structure. By contrast, my device requires no external support frame.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
SUMMARY OF THE INVENTION
Briefly, the invention comprises a spinning lamp shade which is powered by the waste heat from the bulb of the lamp. The rising air currents created by the bulb are directed so as to impinge upon angularly directed vanes and thus impart angular momentum to a decorative lamp shade integral with the vanes. A vertically projecting needle is removably attached to the shade to seat within a central bearing which, in turn, supports the shade and vane apparatus. The shade and vane apparatus is die cut from a pliable single flat sheet of material and held in a frustoconical form by the pinning of several points on the sheet at the center at the top of the shade. The needle is anchored to the shade at this center, and depends therefrom.
Preferably, a rivet or similar article is employed both to pin the sheet as described above, and also to provide the needle. This becomes particularly advantageous where suitable rivets are commercially available. No new or separate component need be provided where such a rivet is employed.
A support engaging the bulb and supporting the shade by receiving the needle is provided by a wire coiled about the light bulb. The spring has an expanded section for engaging the bulb, and a tightly wound secton for securely supporting a bearing. A cup is resiliently held within the coiled wire, and forms the bearing receiving the point of the needle. The cup is manually pressed into and removed from the wire support. This enables ready replacement of the bearing cup.
The cup has a broad, flat floor surface which both affords additional space or area for the needle, thereby compensating for possible inclination of the bulb, and also enables the needle to travel randomly thereover when the cup is horizontally oriented, thereby reducing localized wear to the bearing.
The point of contact with the cup or bearing is much lower with respect to the shade than occurs for example in the U.K. device. A consequence of this arrangement is that dynamic stability is improved over the U.K. device. This is a desirable attribute since in some applications, notably when employed with light bulbs mounted tenuously upon Christmas trees and the like, the bulb may be susceptible to swaying and to transient air currents.
A significant advantage of the novel arrangement is that the needle is contained within the shade, which partially surrounds the point of the needle, and also visually obscures the needle. This sheltered location has a greater tendency to protect a user's fingers from contact with the sharp point of the needle. Even the partial obscurity of the needle may prove a boon in reducing likelihood of attracting the attention of children, who might otherwise become interested in the needle and sustain injury by puncture or the like.
Accordingly, it is a principal object of the invention to provide a new and improved convection rotated ornament device which overcomes the disadvantages of the prior art in a simple but effective manner.
It is a major object of this invention to provide a convection rotated ornament for incandescent light bulbs which is easily attached to existing bulbs without the use of tools.
It is another object of the invention to provide a convection rotated ornament for incandescent light bulbs which covers the attached bulb completely, in the manner of a lamp shade, thus substantially altering the ornamental and lighting effect of the combination.
A further object of the invention is to improve stability of the ornament.
It is again an object of the invention to protect users from ready access to the sharp point of the needle.
Yet another object of the invention is to enable ready replacement of the bearing.
It is another object of the invention to provide a convection rotated ornament for incandescent light bulbs which is rotated by convective air currents generated by waste heat from an associated incandescent light bulb.
A further object of the invention is to employ a commercially available article to assemble the invention and to assist in forming an effective pivoting bearing.
It is another object of the invention to provide a convection rotated ornament for incandescent light bulbs which is formed as a lamp shade and is rotated about a single needle bearing at the central part of the top of the shade.
It is another object of the invention to provide a convection rotated ornament for incandescent light bulbs which is formed as a lamp shade and requires no external support frame structure.
It is another object of the invention to provide a convection rotated ornament for incandescent light bulbs which is formed as a lamp shade and requires no internal support frame structure.
It is still another object of the invention to provide a convection rotated ornament for incandescent light bulbs which is formed as a frustoconical lamp shade with its larger cross sectional area at its bottom so as to serve as a converging funnel for air currents as they pass upward and to thereby increase the velocity of the air currents and to maximize their momentum and the propulsive force for rotation.
It is another object of the invention to provide a convection rotated ornament for incandescent light bulbs which is formed as a lamp shade and which is solely supported upon a needle point and is thus naturally and perpetually aligned in a vertical plane so as to maximize the vertical convective air currents providing the propulsive force for rotation.
It is another object of the invention to provide a convection rotated ornament for incandescent light bulbs which is formed as a lamp shade with integral turbine vanes across its top and which vanes are formed so as to have a greater angle of incidence with vertically directed air currents nearer the outer radius of the vanes thus creating an efficient turbine for maximizing the rotative effect of the air currents.
It is another object of the invention to provide a convection rotated ornament for incandescent light bulbs which is formed as a lamp shade and which is made of a translucent or transparent decorated material to allow the light from the associated light bulb to pass through, creating a moving lighted display on the surroundings.
It is a further object of the invention to provide a spring which engages both the bulb and supports the bearing.
Yet another object of the invention is to provide bearing means accommodating tilting of the bulb, and mitigating wear to the bearing.
It is a general goal of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.
The present invention meets or exceeds all the above objects and goals. Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
Various other objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:
FIG. 1 is a perspective environmental view of the invention attached to a representative bulb of a conventional string of lights.
FIG. 2 is an environmental view of the invention, partially broken away and drawn to enlarged scale.
FIG. 3 is a layout of a flat pliable piece of material which can be properly formed to create the shade and vane portion of the invention.
FIG. 4 is a side elevational detail view taken from the top of FIG. 2, shown partially in cross section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The convection rotated ornament of the present invention is generally designated by arrow 1 of FIG. 1. The device comprises the following main parts; shade and vane portion 10, needle and rivet assembly 20, needle support assembly 30 (see FIG. 2), and conventional incandescent bulb parts 40.
The conventional bulb parts 40 are shown in detail here only to illustrate one preferred environment in which the invention can be used. Electrical plug (not shown) supplies voltage through wire 3 and fused switch (not shown) to bulb receptacle 5. Receptacle 5 includes mounting clip 6 for connection to a Christmas tree limb. Of course clip 6 could be placed over any other convenient hanging point on the article to be decorated by the device. Also, it will be obvious to the artisan that receptacle 5 could form a free standing support such as found on decorative electric candle lamps. It is important to note at the outset that the bulb need not be supported in a perfectly vertical orientation for the proper operation of the device. Substantial canting or tilting of the bulb is permissible so the clip 6 need not be adjustable in any way.
Bulb 7 is lit by electrical energy from plug (not shown) in the conventional manner. It is well known that a light bulb produces a considerable amount of waste heat as it is operated. This invention takes advantage of the convective air currents generated by that heat.
As bulb 7 warms the surrounding air its density is decreased and the lower density air begins to rise by virtue of its buoyancy with respect to the denser outer air. This causes an updraft in the direction of arrow A1 which is captured in lower opening 15 of shade 10. The velocity of the air flow is increased as it rises in the shade by virtue of the fact that the cross sectional area of the conical shade decreases in the upward direction. At the top of the shade 10 the air flow impinges on the vanes V and it is deflected generally in the direction of arrow A2. This change in the direction of the air flow represents a change in velocity of the air stream which has been caused by the vanes. The vanes are urged in the opposite direction by the reaction to the impulse which redirected the air and the entire shade and vane portion 10 is urged to turn about vertical axis A.
Integral shade and vane portion 10 will now be described in detail. As seen in FIG. 1, the overall shape of the formed shade and vane portion is frustoconical with a large open lower circular area 15 and smaller upper circular area (not shown) which is partially closed by vanes V. Vanes V are bent so that angled air passages exist for heated air to escape from the top of the shade after being deflected by one of the vanes V. The deflection of the air by the vanes creates an equal and opposite force reaction on the vanes which creates a net turning moment of the entire shade about a central vertical axis A. In a sense, the device acts much like a wind mill with the "wind" being created by the heat of the bulb. As described later, the shade is supported so as to be freely rotatable about vertical axis A so that the net turning moment will cause the entire shade and vane assembly to rotate in a counterclockwise direction as viewed from the top.
An important feature of the vanes may be seen in FIG. 1 by comparing the incidence angle of a typical vane V at its central portion 12 with the increased incidence angle near its outer periphery 11. Note the airflow is approximately normal to the vane surface near the center of the vane V and is angled substantially to the surface of the vane at the outer periphery of the vane at 11. Those familiar with efficient turbine blade design will recognize this varying angle of incidence in the radial direction as being important in taking into account the greater retreating velocity of the vanes near the outer periphery.
An important feature of the overall conical shape of the shade is that the diverging conical section, in the upward direction, will cause the velocity of the air flow to increase as it rises. The velocity of the air as it impinges on the turbine vanes is directly proportional to the rotational impulse delivered to the vanes. The conical constriction cannot be made too severe, however, because the area at the top would become too small to hold effective sized vanes.
The final rotational speed will be achieved when the net turning moment of the rising hot air is just balanced by the rotational resistance offered by needle bearing assembly 30 and the frictional wind resistance of the shade. Of course the turning speed could be adjusted by using different wattage lamp bulbs. The artisan will see many other ways of adjusting the rotational speed such as by skewing the vanes so as to present a different angle of incidence to the airflow. Also, a portion of the incoming air stream at the bottom 15 of the shade could be obstructed or a few of the vane outlets could be plugged.
Shade and vane portion 10 is formed from a single sheet of thin pliable material. Paper has proved adequate, although plastics and still other materials could be employed. In fact, papers containing a certain clay content have exhibited superior resistance to flammability, compared to most plastics available in sheet form.
Shade 10 performs a conventional role in limiting or blocking excessive or bright light emanating from bulb 7. As seen in FIG. 1, shade 10 is preferably imprinted with an ornamental design.
FIG. 3 shows a layout of the flat sheet as it is shaped and cut prior to forming into a shade. The shapes can be stamped or die cut from flat sheets of stock material. Generally a circular frustrum arc is formed with a series of identical ears 13 facing the center of the overall arc. Each ear is pierced with a circular aperture 14 as seen in FIG. 3. The sides of the ears are formed as S-shaped curves and lie adjacent one another in the flattened mode. It will be noted the series of circular apertures 14 also lie upon a circular arc in the flattened condition.
When the shade is created the individual circular apertures are pulled so as to lie atop one another in a collinear relationship. This in turn deforms the remaining portion of the blank into the frustroconical shape of FIG. 1. The individual ears form the vanes of the finished structure and the aligned circular apertures are fastened together with a rivet assembly 20. Rivet assembly 20 comprises a rivet having an expanded head which occupies the aligned circular apertures, the longitudinal dimension of the rivet being arranged vertically and generally coinciding with the axis of rotation of shade and vane portion 10.
A small tab 18 is arranged to overlap the other side of the cone as the blank is deformed for gluing or otherwise fastening the two opposite sides together. This final fastening permanently holds the blank in the final frustoconical form. If desired, the frustoconical form can first be rolled up and the ears bent atop one another as a secondary step.
An advantage gained from forming the shade and vanes from a single sheet of material is that all corners and crevices naturally deform to the shape of minimal internal stress. These minimum stress curvatures are gentle and also form ideal flow paths for a fluid. This allows the convective air to flow smoothly (laminar flow) throughout the interior of the device without turbulence. The lack of turbulent energy loss also tends to increase the efficiency of my device for turning bulb heat into physical rotation.
Another advantage of the single sheet construction of the shade and vanes is the inexpensive nature of the entire process. A multitude of shades and vanes can be made from a single sheet of stock material. There is no supporting frame, external or internal, required as the formed structure is sturdy and relatively rigid, even when made from paper or cardboard.
Another advantage of the single sheet construction of the shade and vanes is the natural swept back contour imparted to the vanes. The advantages of changing the angle of attack of the vanes in the radial direction have been discussed above.
As shown generally in FIG. 2, shade and vane portion 10 is supported from needle 22, which needle 22 is seated in a bearing or cup 32 of needle support assembly 30. Needle 22 projects downwardly from rivet assembly 20, and contacts the upper floor surface 34 (see FIG. 4) of cup 32. An advantage of employing a rivet is that the rivet both secures the single sheet forming shade and vane assembly 10, and also has needle 22 formed integrally therewith. Rivets are commercially available, and thus a pre-existing article may be exploited to serve two purposes in construction of the invention. Needle support assembly 30 is covered by a protective or decorative cap 24.
Needle 22 provides a pivot fixed to shade and vane portion 10. Needle 22 occupies the central or rotational axis of shade and vane portion 10. Shade and vane portion 10 is thus rotatably or pivotally supported on bulb 7. Convection driven rotation proceeds when bulb 7 heats surrounding ambient air.
Cup 32 is removably entrapped within support assembly 30, which comprises a spiralled support spring. Cup 32 need not be adhered, welded or otherwise fastened. If such construction were required, careful orientation of cup 32 would be required during installation and replacement. Support assembly 30 has a tightly wound upper section 36 and an expanded lower section 38. Upper section 36 receives and retains cup 32. Upper section 36 easily distends under manual pressure to receive, conform to, and release cup 32 during insertion and removal of cup 32. Lower section 38 clings to bulb 7, and is expanded to avoid unduly obstructing light.
An important feature of lower section 38 is the fact that its inward spiral makes it adaptable to perch atop bulbs of a wide variety of shapes and sizes. No matter what diameter bulb is involved, there will come a point where the spiral will just mesh with that diameter. The resilient nature of the spring material will permit it to expand slightly, at that mesh point, and grip the bulb firmly.
FIG. 4 shows retention of cup 32 by support assembly 30 in greater detail. Cup 32 resiliently snap fits into upper section 36 of support assembly 30. It will be apparent from examination of FIG. 4 that when shade assembly 10 is lifted therefrom, there is no exposed sharp point which could injure a person. Also, surface 34 is sufficiently broad or wide to accommodate some inclination of bulb 7 (see FIG. 2) while still seating the point of needle 22. When surface 34 is horizontal, needle 22 can travel randomly thereover, which would mitigate a possible tendency of the point of needle 22 to bore through surface 34. This characteristic contrasts with partially spherical or conical configuration seen in the corresponding bearing surfaces in the prior art.
The artisan will note that the single point suspension of the shade will cause the center of gravity of the shade to lie directly below the needle point regardless of the direction the needle is pointed. This means the shade will hang perfectly vertical even if the bulb and attached spring and needle are canted. The convective currents, generated by the heat of the bulb, are also perfectly vertical in the absence of outside drafts. Thus it may be seen the shade, with its integral vanes, is always precisely aligned to take maximum advantage of the feeble energy available in the convective currents generated by a low wattage bulb.
It is noted the needle and support assembly provide a path for heat conduction which allows heat energy to be removed from the bulb without performing the desired function of heating air. However, the minuscule conduction area provided at the needle point renders this effect negligible.
I prefer to use paper having clay content for my shade and vane material. Such a material is easy to decorate with various forms of colorful art work so as to improve the esthetic impact of the device. Of course, it will be recognized that many materials could be used for the shade, the primary requisite being the pliability required to roll and bend a blank sheet to the final form. It would also be possible to construct a die of the final form and then make multiple shades from the die. With this approach, production costs can be held to an absolute minimum.
It is to be understood that the provided illustrative examples are by no means exhaustive of the many possible uses for my invention.
From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. For example, the artisan could easily determine how to change the conical divergence of the air flow or the number of turbine vanes by making simple changes to the layout blank.
It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims:
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A spinning ornamental incandescent bulb cover has a shade portion and a spinning turbine vane portion formed from a single flat sheet of flexible material. Convective air currents, generated by the heat of the bulb, are passed over the turbine vanes to rotate the entire shade. No internal or external support frame structure is required for the shade or the turbine vanes. The turbine vanes meet at a common central point at which there is located a downwardly directed needle which rides in a bearing to allow rotation. The bearing is provided by a small cup held by a spring which engages the bulb. The needle point support also provides for automatic vertical alignment of the shade regardless of the orientation of the needle. The overall shape of the shade is frustoconical so as to converge the convective air currents and increase their velocity relative to the turbine vanes. The turbine vanes have a varying angle of attack in the radial direction for increased efficiency.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to tunnel and like wall cleaning apparatus, and more particularly to readily portable wall cleaning apparatus for cleaning those portions of a tunnel wall or the like located behind railing means placed along the walkway typically provided along the tunnel wall.
2. Description of the Prior Art
In a tunnel, such as an automobile freeway tunnel, it is desirable to periodically clean the walls to remove accumulations of dirt, automobile exhaust, etc.
My U.S. Pat. No. 3,748,680 discloses a self-propelled tunnel cleaning apparatus mounted on a truck which moves along the roadway in the tunnel. The device utilizes a cylindrical brush which may be selectively positioned against the tunnel wall.
Lenhart U.S. Pat. No. 3,473,180, discloses a self-propelled wall scrubbing and buffing machine having a staggered array of flat, circular brushes. The device is guided by the operator who manually steers the device.
Rainey et al U.S. Pat. No. 3,641,618; and Bonami U.S. Pat. No. 3,806,979, disclose various devices operable along an overhead rail system, and which are suspended from the rail being cleaned.
Hirt U.S. Pat. No. 3,457,574, discloses a cleaning device for marker posts on highways or the like having a pair of counter-rotating cylindrical brushes. The device is trailer mounted and is towed along the roadway by a vehicle which supplies it with power through the vehicle's power take-off shaft.
Hodges U.S. Pat. No. 3,643,274, discloses a cut mounted trough cleaning apparatus which utilizes guidance wheels to cant a cylindrical brush within the trough in order to more effectively clean the trough. The cart is towed by a vehicle which supplies power to the cleaning apparatus.
Hartunian U.S. Pat. No. 3,830,430, discloses a self-propelled cleaning device for cleaning the inside of a chamber such as a truck body. The device utilizes high pressure sprays for cleaning and opposing guidance wheels to orient the device within the chamber.
Grant U.S. Pat. No. 3,099,852; and Ventrella U.S. Pat. No. 3,196,427, disclose self-propelled cleaning devices utilizing a cleaning brush mounted on the end of a boom.
Wilson U.S. Pat. No. 2,636,198, and Rousseau U.S. Pat. No. 2,876,472, disclose portable cleaning machines for vehicles utilizing a vertically oriented cylindrical brush and adapted to be transported by a forklift type vehicle.
Posner U.S. Pat. No. 3,543,319, and Petite U.S. Pat. No. 3,865,034, disclose self-propelled devices having a U-shaped frame carrying cylindrical brushes on two sides of the frame for washing trailers and railroad cars, respectively.
Wilson U.S. Pat. No. 2,804,635 discloses a manually propelled, cart mounted vehicle washing device utilizing a vertically oriented cylindrical brush. Power and water are supplied to the cart from an external source through conduits.
Leikweg U.S. Pat. No. 2,950,492, discloses a truck mounted vehicle washing machine utilizing a vertically oriented cylindrical brush.
Whitsitt U.S. Pat. No. 1,823,222, and Byron et al U.S. Pat. No. 2,253,609, disclose railroad car cleaning devices utilizing a reciprocating rack of rectangular brushes and a vertically oriented cylindrical brush, respectively.
SUMMARY OF THE INVENTION
In basic form, the present invention includes a guidance carriage adapted to engage the guard or hand railing typically found alongside a walkway alongside a tunnel to be cleaned, wherein the guidance carriage is movable longitudinally along the railing. A support carriage carries a plurality of motor driven, rotatable surface cleaning devices. Biasing components, connected between the guidance carriage and the support carriage, urge said carriages in opposite directions, the support carriage in turn urging the surface cleaning devices into contact with the tunnel wall and the guidance carriage being urged by the biasing devices against the railing which provides horizontal support for the guidance carriage.
Such a tunnel or like wall cleaning apparatus achieves a basic feature and advantage of the present invention, in the sense of being adapted to clean those portions of a wall laterally behind the railing typically found along a tunnel walkway.
Other aspects of the present invention involve the surface cleaning devices involving a plurality of generally flat, circular brushes, each of which is canted about a generally vertical axis passing through one of its diameters to ensure contact of its leading or trailing edge portion despite the wall's curvature, vertically considered.
Other aspects of the tunnel wall cleaning apparatus of the present invention involve wall contacting wheel means on the support carriage. Such a construction helps to achieve one of the objects of the present invention, that of enabling the cleaning device to ride over an obstacle or obstruction on the wall.
A further aspect of the present invention is the adaptation of the wall cleaning apparatus to be towed by a vehicle riding on the roadbed within the tunnel, inboardly of the walkway. The towing vehicle typically also supplies the tunnel cleaning apparatus with power, compressed air, cleaning solution and rinsing solution. This helps achieve another object of the present invention, that of keeping the weight of the cleaning apparatus at a minimum so that it may be readily and manually installed behind and removed from the railing.
Other aspects of the present invention include construction of the cleaning apparatus so that the guidance carriage and the support carriage are removably engageable with each other. Such a construction also helps to achieve the foregoing object, since by so making the guidance carriage and the support carriage separable, the machine may be conveniently dismantled into two basic components which may be then inserted and removed by hand from behind the railing along the wall, without the aid of mechanical lifting devices.
Another object of the present invention is to provide a cleaning apparatus adapted to clean tunnel or like walls of either curved or flat configuration.
These and other objects, features, advantages and characteristics of the cleaning apparatus of the present invention will be apparent from the following more detailed description of a typical embodiment thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view from an upper aspect of the cleaning apparatus of the present invention, shown in place to clean portions of a tunnel wall behind a walkway railing;
FIG. 2 is a side elevation view of the cleaning apparatus shown in FIG. 1;
FIG. 3 is a front elevational view of the cleaning apparatus shown in FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, the cleaning apparatus of the present invention is shown in a typical freeway or the like tunnel having a side wall 10, a walkway 12, a roadbed 14, and a railing separating the walkway from the roadbed.
The railing shown includes a plurality of vertical supports 18 and two horizontal bars 20, 22.
The cleaning apparatus shown includes two main assemblies. The first of these is the guidance carriage and assembly which includes a guidance carriage 24 which is adapted to engage the railing 16. Secured to the guidance carriage 24 are two horizontal rollers 26 which engage the top bar 22 of the railing, thereby enabling the railing 16 to provide vertical support for the guidance carriage 24, and enabling the guidance carriage 24 to travel along the railing 16. Four vertically oriented rollers 28, which engage the horizontal bars 20, 22 of the railing, are also fastened to the guidance carriage. The rollers 28 serve to transfer horizontal loading of the guidance carriage 24 to the railing 16 which provides horizontal support for the guidance carriage.
Also mounted on the guidance carriage 24 are a pair of horizontally oriented channel members 30, 32 which extend from the guidance frame 24 toward the side wall 10 of the tunnel. Mounted to the channel members 30, 32 are a pair of penumatic biasing cylinders 34, 36 having a pair of push rods 38, 40. To the top of the front channel member 30 is secured a tow bar 42 for the guidance carriage.
Also mounted to the guidance carriage is a railing spray bar 43 for spraying rinsing solution on the railing.
The second main assembly of the tunnel cleaning apparatus of the present invention is the support carriage assembly which includes a support carriage 44 which rides on front and rear wheels 46, 48. As seen, the front and rear wheels engage the surface of the walkway 12 so that the walkway provides vertical support for the support carriage 44. The support carriage includes a pair of push plates 50, 52 against which the push rods 38, 40 of the pneumatic biasing cylinders are adapted to bear. Above the top of the front push plate 50 is a U-shaped opening 54 which is adapted to receive the tow bar 42 for the guidance carriage.
Secured to the front portion of the support carriage 44 are a pair of obstacle avoidance wheels 56 whose function is described subsequently. Journaled to the support carrier 44 are four flat circular brushes 58, of conventional construction. The four circular brushes are driven through two drive chains 62, 64 by a hydraulic motor 60 which is secured to the support carriage 44.
Referring now to FIG. 2, it is seen that a cleaning solution dispensing spray bar 66 is secured to the front of the support carriage 44, while a fresh water rinse spray bar 68 is secured to the rear portion of the support carriage. Not shown in FIG. 1 for clarity, but shown in FIG. 2, are the compressed air delivery lines 70, 72, 74 which supply the pneumatic biasing cylinders 34, 36 with compressed air. Also shown in FIG. 2 are the hydraulic supply 76 and return 78 lines for the hydraulic motor 60, the cleaning solution supply line for the front spray bar 66, the rinsing solution delivery line 82 for the rear spray bar 68, and the rinsing solution delivery line 83 for the railing spray bar 43 which is connected to the supply line 82. The compressed air delivery line 70 which supplies compressed air to the regulator 84, the delivery 76 and return 78 lines for the hydraulic motor 60, and the delivery lines 80, 82, 83 for the front and rear spray bars 66, 68, 43, respectively, are all removably connected to their respective components by conventional snap couplings 86.
The compressed air, the hydraulic fluid under pressure, the cleaning solution and the rinsing solution are supplied from a vehicle tracking along the roadbed, inboardly of the walkway, and which tows the support carriage 44 by means of the tow bar 88 which is pivotally connected to the front of the support carriage by a link pin 98.
It is an important feature of the present invention that it can be used to clean curved tunnel walls, such as that shown in the drawings. However, in order to most effectively employ the circular flat brushes 58 to clean the curved tunnel side wall 10, it is preferable to mount the brushes 58 on the support carriage 44 so that each brush is canted about a generally vertical axis passing through one of its diameters. It will be appreciated that, as seen in FIG. 3 such canting ensures that the leading edges of the flat circular brushes 58 engage the tunnel side wall 10 despite any curvature thereof. Of course, it is to be understood that the brushes could be canted so that their trailing edges, instead of their leading edges engage the curved tunnel wall. Since most tunnels have a substantial diameter, the amount of canting in order to ensure that the brushes engage the curved tunnel side wall 10 most effectively is fairly small. Thus, the cleaning apparatus of the present invention can also be used to clean a vertically planar wall simply by readjustment of the attitude of the brushes.
It is to be also understood that the previously described support carriage assembly and the guidance carriage assembly are basically separate components. Their only interconnections are the tow bar 42 for the guidance carriage 24 and the push rods 38, 40 of the pneumatic biasing cylinders which are adapted to push against the push plates 50, 52 of the support carriage 44. The push rods 38, 40 are not secured to the push plates 50, 52. Thus, as it will be appreciated, the guidance carriage 24 and its associated components are readily removable from the railing 16 and can be taken away while leaving the support carriage 44 and its associated components leaning against the tunnel side wall 10.
The assembly for use and operation of cleaning apparatus according to the present invention is next considered. To place the equipment in operation, the support carriage 44, along with all the components secured thereto, are lifted over the railing 16 and positioned against the tunnel side wall 10, as shown in the drawing. It is notable that the support carriage 44 and its associated components are light enough in weight so that they are emplaceable and removable from behind the railing 16 by two men manipulating such manually, without the necessity of having a crane or other mechanical lifting device present.
With the support carriage in place, the guidance carriage 24 is lifted over and placed upon the railing 16 so that its horizontal and vertical rollers 26, 28 are in engagement with horizontal bars 20, 22 of the railing, as also shown in the drawings. The guidance carriage is light enough so that it also may be positioned on the railing by two men, without need to any mechanical lifting device. As the guidance carriage is lowered into position on the bars 20, 22 of the railing, care is to be taken so that the tow bar 42 for the guidance carriage engages the U-shaped opening 54 in the support carriage. This ensures that the guidance carriage and the support carriage are correctly aligned so that the push rods 38, 40 for the pneumatic biasing cylinders are positioned adjacent the push plates 50, 52 of the support carriage.
Next, the tow bar 88 for the support carriage is pivotally connected to the of carriage by means of a link pin 90 and the ends of the supply and return lines 70, 76, 78, 80 and 82 are connected to their respective components by their snap couplings 86. The other end of the tow bar 88 and the other end of the supply and return lines 70, 76, 78, 80, 82 are connected to a suitable tow vehicle, such as the tunnel cleaning apparatus disclosed in my aforesaid U.S. Pat. No. 3,748,680. Since the tow bar, as well as the vehicle, which includes conventional mechanisms to supply the tunnel cleaning apparatus of the present invention with compressed air, hydraulic fluid under pressure, cleaning solution and rinsing solution, of themselves form no part of the present invention, their construction need not be further described.
After being so assembled and arranged to be towed, the cleaning apparatus of the present invention is now ready for use. The specific sizings of the components hereafter mentioned are by way of non-limiting example only. As hydraulic fluid is supplied through conduit 76 under pressure to the ten horsepower hydraulic motor 60, the circular brushes 58, which are two feet in diameter and have four inch brushes, are driven to rotate counterclockwise at a speed of about 200 rpm. Cleaning solution under pressure is supplied to the front spray bar 66 through the cleaning solution supply line 80, and rinsing solution is supplied to the rear spray bars 68, 83 through the rinsing solution supply line 82, 83. The front, cleaning solution dispensing spray bar 66 is so oriented as to thoroughly wet the wall 10 with the cleaning solution ahead of the circular brushes 58. Similarly, the rear, rinsing solution dispensing spray bar 68 is so oriented as to thoroughly rinse the wall 10 behind the cleaning apparatus of the present invention after the wall has been cleaned by the brushes. The railing spray bar 83 serves to clean the railing.
The support carriage 44 is urged against the wall 10 by the push rods 38, 40 of the one and one-half inch pneumatic biasing cylinders 34, 36 which are supplied with compressed air at about twenty psig through compressed air lines 70, 72, 74. Pneumatic, rather than hydraulic, biasing cylinders are preferred because of the obstacle avoidance wheels 56 at the front of the support carriage 44. If the apparatus of the present invention should encounter an obstacle, such as an electrical conduit or water pipe attached to or standing out from the wall, said wheels 56 enable the front of the apparatus to yieldingly "walk up" and over the obstacle. As the wheels 56 ride up over an obstacle, the support carriage 44 is forced somewhat toward the guidance carriage 24. However, the biasing cylinders 34, 36, since they are pneumatic (and since the contained air is compressible) are able to accommodate this motion, without adjusting the pressure of the compressed air supplied thereto, and the support carriage 44 and brushes 58 are automatically returned to their original positions once the obstacle is passed by.
It should be noted that the wheels 56 also serve to prevent the pneumatic biasing cylinders 34, 36 from urging the support carriage 44, and thus the circular brushes 58, too closely against the wall 10, which might overcompress the bristles and thus lead to early failure of the brushes.
The cleaning apparatus is drawn along the walkway as the towing vehicle courses the roadbed 14, the support carriage 44 being in tow by means of the tow bar 88. The support carriage in turn tows the guidance carriage 24 down the railing 16 by means of the guidance carriage tow bar 42 which is engaged in the previously described U-shaped opening 54 in the support carriage.
It is to be understood that the walkway provides vertical support for the support carriage 44 which rides thereon on its wheels 46, 48, while, the vertical support for the guidance carriage 24 is supplied by the railing 16. It is preferred that the support carriage and the guidance carriage do not carry any of the weight of the other. Horizontal loading of the guidance carriage caused by the action of the pneumatic biasing cylinders 34, 36 is absorbed by the railing 16 which provides horizontal support for the guidance carriage. Of course, the wall 10 provides horizontal support for the support frame 44 and its associated components which are urged thereagainst by the biasing cylinders 34, 36.
As will be apparent, disassembly and removal of the cleaning apparatus from behind the railing occurs in the reverse order of the assembly of the apparatus behind the railing, and need not be further described.
From the foregoing, various further applications, modifications and adaptations of the apparatus disclosed in the invention embodied therein will now be apparent to those skilled in the art to which the invention is addressed, within the scope of the following claims.
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Cleaning apparatus usable to clean those portions of a tunnel wall or the like which are located behind railing means typically placed along a walkway beside the wall, such as in a freeway tunnel. A guidance carriage engages the railing and is movable therealong. A support carriage, which can be moved along the walkway, carries a plurality of motor driven circular brushes for cleaning these wall portions. Between the guidance carriage and the support carriage are located linear fluid motors urging the carriages in laterally opposite directions, the support carriage in turn urging the brushes into contact with the wall, and the guidance carriage being urged by said motors against the railing which provides horizontal support for the guidance carriage. The railing also provides vertical support for the guidance carriage while the walkway provides vertical support for the support carriage. The guidance carriage and the support carriage may be removably engageable with each other to enable the cleaning apparatus to be easily positioned on and removed from the walkway.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] Embodiments of the present invention generally relate to clamps. More particularly, the invention relates to bar clamps. Still more particularly, the invention relates to a coupling configured to connect a pair of bar clamps.
[0003] 2. Description of the Related Art
[0004] Traditional bar clamps are well known in the tool industry for temporarily clamping two workpieces together in order to perform an operation on one or both of the workpieces such as a gluing operation. In recent years, a quick action bar clamp has been introduced to the tool industry. The quick action bar clamp generally includes several clamp components such as a fixed jaw, a slide bar, and a movable jaw. The moveable jaw includes a trigger handle grip assembly for releasably engaging the slide bar to allow the movable jaw to easily move on the slide bar relative to the fixed jaw.
[0005] Typically, the components of the quick action bar clamp are sold in a set rather than being sold separately. For example, most quick action bar clamps are sold in varying standard bar lengths, with the clamp components attached. The quick action bar clamps are generally marketed by the size of the workpiece, such as a clamp capable of clamping a 6″, 12″, 18″, 24″ 30″ or 36″ size workpiece. Among other things, one reason the clamp components are not sold separately from the slide bar is to prevent the users from purchasing one set of clamp members for use with varying slide bar lengths and/or from purchasing replacement clamp members and slide bars.
[0006] The problem associated with the standard quick action bar clamp is the limited range of clamping capability for each individual bar clamp. For instance, a user must purchase a 12″ bar clamp for a workpiece that is 12″ or less and then the user must purchase another bar clamp for workpiece that is longer than 12″. Thus, the user is required to have an individual bar clamp for each different length of workpiece. Another problem associated with the standard quick action bar clamp occurs when the workpiece is an odd length, such as 45″ long. In this instance, the user must locate a nonstandard size quick action bar clamp which may not be readily available in a local hardware store.
[0007] A need therefore exists for a method and an apparatus capable of utilizing standard quick action bar clamps for clamping a variety of different length workpieces. Further, there is a need for a method and an apparatus capable of utilizing standard quick action bar clamps for clamping an odd size workpiece.
SUMMARY OF THE INVENTION
[0008] The present invention generally relates to a method and an apparatus for use in coupling a pair of bar clamps. In one aspect, a coupling member for connecting a first clamp to a second clamp is provided. The coupling member includes a first member and a second member having an end pivotally attached to the first member. The coupling member further includes a connection member for attaching an end of each clamp to the coupling member.
[0009] In another aspect, a connection member for coupling a pair of bar clamps is provided. The connection member includes a body movable between an open position and a closed position. The connection member further includes an attachment member on the body for connecting an end of each bar clamp to the connection member. Additionally, the connection member includes a lock member for selectively locking the body in the closed position.
[0010] In another aspect, a method of connecting a first bar clamp to a second bar clamp is provided. Each bar clamp includes a fixed jaw attached to a slide bar and a selectively movable jaw releasably attached to the slide bar. The method includes reversing the orientation of the moveable jaw relative to the fixed jaw on each bar clamp. The method further includes positioning an end of the first bar clamp adjacent an end of a coupling member and positioning an end of the second bar clamp adjacent another end of the coupling member. Additionally, the method includes attaching the end of each bar clamp to the coupling member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
[0012] FIG. 1 is a perspective view illustrating a coupling member of the present invention with a first bar clamp and a second bar clamp.
[0013] FIG. 2 is a perspective view illustrating the coupling member connecting the first bar clamp to the second bar clamp.
[0014] FIG. 3 is a view illustrating the coupling member in an open position.
[0015] FIG. 4 is a view illustrating the coupling member in a closed position.
[0016] FIG. 5 is another view of the coupling member in the closed position.
DETAILED DESCRIPTION
[0017] The present invention is generally directed to a coupling for quick action bar clamps. Various terms as used herein are defined below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term, as reflected in printed publications and issued patents. In the description that follows, like parts are marked throughout the specification and drawings with the same reference numerals. The drawings may be, but are not necessarily, to scale and the proportions of certain parts have been exaggerated to better illustrate details and features described below. One of normal skill in the art of clamps will appreciate that the various embodiments of the invention can and may be used in all types of clamps.
[0018] FIG. 1 is a view illustrating a coupling member 100 of the present invention with a first bar clamp 10 and a second bar clamp 60 . Generally, the coupling member 100 is used to couple or connect the first bar clamp 10 to the second bar clamp 60 to increase the capability of the bar clamps 10 , 60 to handle any number of different workpiece lengths. For ease of explanation, the invention will be described generally in relation to a standard quick bar clamp. It is to be understood, however, that the invention may be employed in any number of bar clamps without departing from principles of the present invention.
[0019] As illustrated in FIG. 3 , the coupling member 100 is generally made from a first member 115 and a second member 120 . One side of the first member 115 is connected to the second member 120 by a hinge member 105 to allow the coupling member 100 to move between an open position as shown in FIG. 3 and a closed position as shown in FIG. 4 . The coupling member 100 also includes a lock member 110 to secure the first member 115 to the second member 120 when the coupling member is in the closed position. The components of the coupling member 100 will be described in greater detail below.
[0020] Referring back to FIG. 1 , the bar clamp 10 , 60 typically includes several standard components. For instance, the bar clamp 10 , 60 includes a fixed jaw 20 , 70 operatively mounted to a slide bar 15 , 65 . The fixed jaw 20 , 70 is capable of holding one portion of a workpiece (not shown). The bar clamp 10 , 60 also includes a selectively movable jaw 25 , 75 that is capable of moving along the length of the slide bar 15 , 65 . Further, the movable jaw 25 , 75 is capable of holding another portion of the workpiece. The movable jaw 25 , 75 moves relative to the fixed jaw 20 , 70 to accommodate the length of the workpiece. Typically, the moveable jaw 25 , 75 includes a trigger handle grip assembly for releasably engaging the slide bar 15 , 65 to allow the movable jaw 25 , 75 to easily move on the slide bar 15 , 65 .
[0021] The bar clamp 10 , 60 typically includes a stop 30 , 80 at an end of the slide bar 15 , 65 to limit the travel of the movable jaw 25 , 75 . In the embodiment shown, the stop 30 , 80 is a pin member, such as a metal roll pin or a rubber grommet. In another embodiment, the stop 30 , 80 may comprise a hole or any other means capable of limiting the travel of the movable jaw 25 , 75 on the slide bar 15 , 65 .
[0022] FIG. 2 is a view illustrating the coupling member 100 connecting the first bar clamp 10 to the second bar clamp 60 . In comparing FIG. 2 to FIG. 1 , it can be seen that the orientation of the movable jaw 25 , 75 has been reversed or repositioned relative to the fixed jaw 20 , 70 . The repositioning of the movable jaw 25 , 75 can be done by removing or disengaging the stop 30 , 80 at an end of the slide bar 15 , 65 and then sliding the movable jaw 25 , 75 off the of the slide bar 15 , 65 , repositioning the movable jaw 25 , 75 and subsequently sliding the movable jaw 25 , 75 back on to the slide bar 15 , 65 in the orientation shown in FIG. 2 . Once the movable jaw 25 , 75 is repositioned, the coupling 100 is moved from the closed position to the open position. Next, the end of the slide bar 15 is positioned adjacent an end of the coupling member 100 and the end of slide bar 65 is positioned adjacent another end of the coupling member 100 and subsequently the end of each slide bar 15 , 65 is secured in the coupling member 100 . Thereafter, the coupling member 100 is moved from the open position to the closed position and secured in the closed position by the lock member 110 . The movable jaw 25 , 75 is then slideable along the slide bar 15 , 65 to accommodate various lengths of workpieces.
[0023] In the embodiment shown in FIG. 2 , the movable jaws 25 , 75 are utilized to accommodate the length of the workpiece. It is to be understood, however, that the invention is not limited to the embodiment shown, rather it is conceivable that only one movable jaw may be used in conjunction with at least one fixed jaw to accommodate the workpiece without departing from principles of the present invention.
[0024] FIG. 3 is a view illustrating the coupling member 100 in the open position. As shown, the coupling member 100 comprises the first member 115 and the second member 120 . The first member 115 is operatively attached to the second member 115 by the hinge member 105 and the first member 115 is attachable to the second member by the lock member 110 when the coupling member 100 is in the closed position. It should be noted that the hinge member and the lock member are shown generally and any number of hinges and locks may be used with the coupling member 100 without departing from principles of the present invention.
[0025] The second member 120 is typically made from a durable material, such as a plastic, a composite or a metal material. The second member 120 includes a continuous shaped groove 130 formed on a surface thereof. The groove 130 is used to receive the slide bar 15 and the slide bar 65 . In another embodiment, a metal or a plastic insert (not shown) may be placed in the groove 130 to enhance the durability of the coupling member 100 .
[0026] As shown in FIG. 3 , the second member 120 includes a first hole 135 and a second hole 140 formed in the groove 130 . Typically, the holes 135 , 140 do not extend through the second member 120 , but rather the holes 135 , 140 are drilled to a predetermined depth. The holes 135 , 140 are generally used to secure the slide bar 15 , 65 to the coupling member 100 . More specifically, in one embodiment, the holes 135 , 140 accommodate a pin attached to each slide bar 15 , 65 , such as a roll pin (stops 30 , 80 ). In another embodiment, the holes 135 , 140 may accommodate a removable threaded member (not shown), whereby the threaded member acts as a pin to work in conjunction with a hole at an end of each slide bar 15 , 65 to secure the slide bar 15 , 65 to the coupling member 100 . In yet another embodiment, the second member 120 may have at least one pin member (not shown) formed on a surface thereof in place of the holes 135 , 140 . The present invention contemplates any combination of pins, holes, threaded members or any other means capable of securing the slide bar 15 , 65 to the coupling member 100 .
[0027] The first member 115 is typically made from a similar durable material as the second member 120 , such as a plastic, a composite, or a metal material. The first member 115 includes a plurality of holes 125 that extend through the first member 115 . The holes 125 are used to store the stops 30 , 80 or extra pins or extra threaded members when the coupling 100 is in operation.
[0028] FIGS. 4 and 5 are views illustrating the coupling member 100 in the closed position. As clearly shown, the first member 115 is secured to the second member 120 by the lock member 110 . Also shown in FIGS. 4 and 5 , the overall geometric shape of the coupling member 100 is rectangular. It should be understood, however, that the coupling member 100 may be any geometric shape, such as spherical, without departing from principles of the present invention.
[0029] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
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A method and an apparatus for use in coupling a pair of bar clamps. In one aspect, a coupling member for connecting a first clamp to a second clamp is provided. The coupling member includes a first member and a second member having an end pivotally attached to the first member. The coupling member further includes a connection member for attaching an end of each clamp to the coupling member. In another aspect, a connection member for coupling a pair of bar clamps is provided. In another aspect, a method of connecting a first bar clamp to a second bar clamp is provided.
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BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention relates generally to photography, and more particularly to an apparatus for assisting a camera in photographing cylindrical objects.
2. DESCRIPTION OF THE PRIOR ART
It is sometimes required to photograph a curved surface of a cylindrical object, such as a fingerprint, for example, on a coat hanger, a soda can, a cartridge casing, or cocaine tooter. However, it is arduous to take several different-angled pictures of the cylindrical object and compose them later into one entire view of the cylindrical object. Accordingly, some attempts have been made to provide devices for automatically photographing the curved surface of the cylindrical object. One such device, for example, is shown in U.S. Pat. No. 3,462,218 issued Aug. 19, 1969 to Pfaff. Pfaff's device moves a camera in a direction parallel to a diameter of a stationary cylindrical object. Although Pfaff's device can automatically photograph several different-angled pictures of the object it has the following disadvantages, namely: Pfaff's device can photograph only a 180° view of the object; the object's image taken by the camera includes distortion since the camera is not moved parallel to the circumference of the cylindrical object; and the object's image taken by the camera is blurred since the camera is moved while vibrated slightly.
An alternative device is shown in U.S. Pat. No. 4,372,659 issued Feb. 8, 1983 to Ogawa. Ogawa's device arranges a cylindrical object on a first disk, and a slit camera and a mirror on a second disk. The 360° view of the object reflected in the mirror is photographed by the camera by rotating either the first disk or the second disk. The successive film frames are exposed in synchronization with the relative rotation of the object. Although Ogawa's device can automatically photograph the 360° view of the object, it has the following disadvantages, namely, Ogawa's device requires the expensive slit camera in which film is fed continuously behind the slit and it is difficult to synchronize the film feeding speed and the rotation speed of the object.
Yet another device is shown in U.S. Pat. No. 4,457,603 issued Jul. 3, 1984 to Gebhart et al. Gebhart et al. discloses a stationary camera and a rotating cylindrical object. Although Gebhart's device can automatically photograph the 360° view of the object, it has the following disadvantages, namely, Gebhart's device requires, like Ogawa's device, a specific camera in which film is fed continuously behind the slit and it is difficult to synchronize the film feeding speed and the rotation of the object.
Japanese Patent Application No. 52-40327 filed by Tomita and Laid-Open Mar. 29, 1977 discloses another device in which three stationary cameras are placed at different-angled positions. Although Tomita's device can automatically photograph three different-angled pictures of the object it has the following disadvantages. Tomita's device can photograph only a 180° view of the object and it is arduous to compose three pictures into one entire view of the cylindrical object.
Other patents which may be deemed of interest is U.S. Pat. No. 3,471,236 issued Oct. 7, 1969 to Pearson which discloses a prism for an optical stroboscope; U.S. Pat. No. 3,517,447 issued Jun. 30, 1970 to Fox which discloses an optical-reimaging system; U.S. Pat. No. 3,820,130 issued Jun. 25, 1974 to Cornelison, Jr. et al. which discloses a golf instruction device; and U.S. Pat. No. 4,063,259 issued Dec. 13, 1977 to Lynch et al. which discloses a method of matching a golfer with a golf ball, a golf club or style of play.
SUMMARY OF THE INVENTION
The present invention relates to an apparatus for assisting a camera in photographing cylindrical objects. The apparatus according to the present invention provides assistance for a stationary camera in photographing a curved surface of an object. The apparatus comprises rotary means and mobile means. The rotary means is coupled to the object for rotating the object around a predetermined axis. The mobile means is coupled to the rotary means for moving the rotary means along a line perpendicular to the predetermined axis. Thus, the object is rotated by the rotary means as it passes through a photograph area of the camera. While the object passes through the photograph area of the camera, the camera shutter is locked open.
A photograph system according to the present invention for photographing a curved surface of an object is made up of a stationary camera, and the aforementioned apparatus optically coupled to the camera for assisting the camera in photographing the curved surface of the cylindrical objects.
According to one feature of the present invention, the camera is stationary so as not to make a blurred image of the object. According to another feature of the present invention, a standard and relatively inexpensive camera may be used for the present invention. According to another feature of the present invention, the speed of the mobile means is controlled to provide sufficient time and the environmental lighting is controlled to provide sufficient illumination. The control of the mobile means and environmental lighting permits the use of the smaller iris opening (lens opening) sizes of the camera which provides a better depth of field. According to another feature of the present invention, the rotary means rotates the object so as to automatically make one entire view thereof.
Accordingly, it is a general object of the invention to provide a novel and useful apparatus for assisting a camera in photographing a cylindrical object in which the above disadvantages are eliminated.
Another object of the invention is to provide a relatively inexpensive device for assisting a camera in photographing a cylindrical object without blur and distortion.
Still another object of the present invention is to provide a apparatus for assisting a camera in photographing a cylindrical object without a complicated synchronization control.
Yet another object of the present invention is to provide a device for assisting a camera in photographing a cylindrical object in which a 360° view of the object can be generated without composing several pictures.
Other objects and further features of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a block diagram of a photograph system according to the present invention.
FIG. 2 shows a front elevation view of a photograph assistance device of the photograph system shown in FIG. 1.
FIG. 3 shows a top plan view of the photograph assistance device shown in FIG. 1.
FIG. 4 shows a partial cross-section of the turntable and the turntable bearing of the device shown in FIG. 1.
Similar reference characters denote corresponding features consistently throughout the attached drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A description will now be given of a photograph system 1 according to the present invention with reference to FIGS. 1 to 4. The photograph system 1 comprises a photograph assistance device 10 and a camera 50. The photograph assistance device 10 is engaged with a cylindrical object 60. The camera 50 is optically connected to the photograph assistance device 10 so that the camera 50 can photograph a curved surface of the cylindrical object 60.
The photograph assistance device 10 according to the present invention comprises a frame 12, a pair of shafts 14a and 14b a turntable 16, a turntable bearing 18, a platform car 20, a driving device 22, and a rail 46. The shafts 14a and 14b are opposite to each other and secured to the frame 12. The turntable bearing 18 is engaged with the turntable 16. The platform car 20 is movably disposed on the frame 12 and coupled to the turntable bearing 18. The driving device 22 is connected to the frame 12 and the platform car 20. The rail 46 is secured on the frame 12 and engaged with a wheel of the platform car 20.
The frame 12 is fixed on a stationary surface. The frame 12 has a rectangular shape, as shown in FIG. 3. As described later, the platform car 20 moves along the longitudinal side 12a of the rectangle from right to left (in a direction H); the longitudinal side 12a is longer than a circumference of the cylindrical object so that a 360° view of the cylindrical object 60 can be photographed by the camera 50.
The shafts 14a and 14b are perpendicularly secured on the frame 12. A direction from the shaft 14a to the shaft 14b is arranged, as shown in FIG. 3, parallel to the direction H. Preferably, each of the shafts 14a and 14b is made of a metallic material so as not to be easily bent. A distance between the shafts 14a and 14b is longer than a moving distance of the platform car 20.
The turntable 16 is concentrically engaged with the cylindrical object 60 so as to rotate it around an axis V shown in FIG. 2. According to this embodiment, a plurality of differentsized turntables 16 have been prepared so as to photograph various sized cylindrical objects 60 without distortion with respect to a moving direction of the object 60. As discussed below, the moving direction of the object 60 is the direction H. These turntables 16 comprise table parts 16a and tubular parts 16b. The turntable 16 may have a groove having a rough inner surface at a side surface thereof so as to be engaged with a turntable-rotating string 44, which will be described later.
The turntable bearing 18 connects the turntable 16 to the platform car 20, and allows the turntable 16 to rotate relative to the platform car 20. As shown in FIGS. 3 and 4, the turntable bearing is secured on the platform car 20 by three screws 20a and three springs 30b. Each screw 20a and each spring 20b determine an elevational distance of the turntable bearing 18 relative to the platform car 20 and a direction of the axis V of the object 60. The direction V can be changed (for leveling the turntable 16) by clamping each screw 20a. If the turntable 16 has no groove to be engaged with the turntable-rotating string 44, then the string 44 can rest against the top side of the turntable 16.
The platform car 20 carries the turntable 18 and the cylindrical object 60 to a photograph area 52 of the camera 50. When cocking the driving device 22, it moves the object 60 in a direction opposite to the direction H. When the driving device 22 is cocked, it compresses a spring disposed therein. When the driving device 22 is released from its cocked position, the spring forces hydraulic fluid through small adjustable jets or apertures located interiorly of the driving device 22, which allows the spring to return to it normal (uncompressed) posture at a slow and constant rate, moving the object 60 from the right to the left in the direction H as the object 60 is rotated around the axis V. The object 60 typically moves from the right to the left over a period of approximately 60 to 90 seconds. The driving device comprises a lever 24, a body 26, a focus lock 28, a shaft 30, a pair of gears 32a and 32b, a transmission shaft 34, a shaft stand 36, a pair of pulleys 38a and 38b, a pulley stand 40, a car-driving string 42, and a turntable-rotating string 44. The body 26 has a shaft 30, one end of which is connected to the lever 24, and the other end of which is connected to the gear 32a. The focus lock 28 is rotatable and engageable with the lever 24. The gear 32b is engaged with the gear 32a. The transmission shaft 34 is rotatably secured on the shaft stand 36 by a plurality of screws. One end of the transmission shaft 34 is engaged with the gear 32b, and the other end thereof is engaged with the pulley 38a. The pulleys 38a and 38b and the platform car 20 are connected via the car-driving string 42. The pulley stand 40 is engaged with the pulley 38b and secured on the frame 12. The turntable-rotating string 44 is suspended between the shafts 14a and 14b while spring-biased.
The lever 24 is movable between uppermost and lowermost positions. Lever 24, located at the midpoint position is engageable with the focus lock so as to be retained at the midpoint position. In the midpoint position (or in the photographing area 54), the camera 50 may be set up and adjusted to photograph the object 60. The body 26 uses a hydraulic motor. However, any type of motor may be used to the present invention. The lever gradually moves upward from the lowermost position by a hydraulic power generated by the body 26. As the lever 24 moves upward, the object 60 moves from the right to the left passing in front of the camera 50 through the photographing area 54.
The gears 32a and 32b are arranged parallel to the direction H. The transmission shaft 34 is arranged vertical to the direction H, as shown in FIG. 3. The pulleys 38a and 38b are arranged parallel to the direction H, and the car-driving string 42 is arranged parallel to the direction H. The car-driving string 42 is wound around the pulleys 38a and 38b while being spring-biased. The rail 46 is engaged with at least one wheel of the platform car 20 and arranged along the direction H so as to guide the platform car 20 along the direction H. The car-driving string 42 may be made of nylon string. The turntable-rotating string 44, preferably wax string, may be engaged with the groove of the turntable 16 or the outer surface of the turntable 16 providing the turntable 16 does not have an outer groove. The friction between the turntable 16 and the turntable-rotating string 44 rotates the turntable 16 as the turntable 16 is moved along the turntable-rotating string 44 by the driving device 22.
The rail 46 guides the platform car 20 with the turntable 16 in the direction H which is perpendicular to an optical axis L of the camera 50, as shown in FIG. 1. The camera 50 photographs the cylindrical object located in the photograph area 52. The camera 50 includes a shutter (not shown) which may be locked open as the object passes through the photograph area 52. The camera 50 includes a lens (not shown) with the optical axis L, as shown in FIG. 1.
In this embodiment, the object 60 has a cylindrical shape. However, the present invention can be applied to the object 60 which has a cylindroid shape.
Next follows a description of an operation of the photograph system according to the present invention. First, the photograph assistance device 10 and the camera 50 are arranged so as to define the photograph area 52 of the camera 50. Then, the cylindrical object 60 is attached to the turntable 16 which has the same size as that of the object 60. In this embodiment, a driving force is applied by the driving device 22 so as to move and rotate the object 60 past the view of the camera 50, without distortion. Distortion is eliminated only if a diameter of the turntable 16 is equal to that of the object 60. Therefore, if the turntable 16 is larger than the object 60, the object's image taken by the camera 50 is stretched in the direction H; whereas if the turntable 16 is smaller than the object 50 compressed in the direction H. According to the present invention, a generating line of the object 60 which is parallel to the axis V is perpendicular to the direction H and the optical axis L of the camera 50 so as to prevent distortion of the object's image with respect to the generating line of the object 60. However, even if the axis V is not perpendicular to the optical axis L of the camera 50, the curved surface of the object can be roughly recognized.
Next, the lever 24 is advanced down and engaged with the focus lock 28. When the focus lock 28 is released, the lever 24 gradually moves upward by means of the hydraulic power of the body 26 and rotates the gear 32a via the shaft 30 of the body 26. In response, the gear 32a rotates the gear 32b with the transmission shaft 34. The pulley 38a engaged with the transmission shaft 34 is consequently rotated moving the platform car 20 along the direction H. The turntable 16 and the object 60 are thus moved along the direction H. The driving device 22 moves the object 60 at a constant speed along the direction H so as not to generate distortion in the image taken by the camera 50.
When the turntable 16 moves in the direction H, friction between the turntable 16 and the turntable-rotating string 44 rotates the turntable 16 counterclockwise. Consequently, the object 60 rotates with the turntable 16. Since the turntable 16 moves at the constant speed, the object 60 is rotated at a constant rotating speed.
The camera begins to expose the object's image when the object 60 enters the photograph area 52 of the camera 50. The shutter (not shown) of the camera 50 is locked open when the object 60 enters the photograph area 52 and is closed after the object 60 passes the photograph area 52. In addition, the photograph area is broad enough to photograph the entire view of the cylindrical object 60.
According to the present invention, the driving device 22 moves as well as rotates the object 60. However, a distinct mobile unit and a rotary unit may be provided. In that case, the mobile unit moves the object 60 at a constant speed, while the rotary unit rotates the object 60 at a constant rotating speed. The turntable bearing 18 and the platform car 20 may be regarded as the mobile unit. Additionally, the camera 50 may be moved in the direction H while the platform 20 is made stationary.
It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims.
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A photograph assistance device for assisting a stationary camera in photographing a curved surface of cylindrical objects, such as a finger print wrapped around a bullet casing or soda can. The cylindrical object is moved at a constant speed into a photograph area of the camera while rotated at a constant rotating speed. The moving speed of the object is preferably determined so that the object can successfully pass through the photograph area of the camera while the camera and stop is adjusted for a small diameter opening for the best depth of field. The rotating speed of the object is preferably determined so that the image of the object can be rotated onto the field without producing a distorted image, that is, a stretched or compressed image.
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BACKGROUND OF THE INVENTION
This relates in general to security ventilating systems, more particularly as such systems are applied to residential and business premises having laterally rolling or sliding doors and/or windows.
In the present-day state of society, breaking and entering into residential and business premises is all too common. Accordingly, it is necessary to augment the conventional types of locks, which skilled burglers can easily circumvent, additional security is especially needed in the case of horizontally sliding glass doors or windows of the types employed in so many modern houses, apartments and stores. During warm weather, it is desirable to open such doors or windows for ventilation; and even if a screen door is interposed in the opening, it can be readily and quietly cut and opened. Moreover, when the doors or windows are closed, the intruder breaks or cuts the glass, and reaches through to unlock the door by manipulating the handle from the inside, which is located in a conventional position visible from the outside; or he may use a tool to force such doors or windows up to unlock, unlatch or force conventional locks to release, actually removing the door or window from its track.
Numerous security systems have been devised in accordance with the prior art, such as various types of grills, window guards, and screens; but none of them is suitable for use with sliding glass doors or windows which are opened to different positions. Moreover, they are either too expensive or cumbersome to install, or the locks are readily identifiable from the outside and easily removed by a skilled burgler having simple tools; or they are too difficult to open to enable escape from an indoor fire. Furthermore, some of the systems of the prior art are too massive and heavy for the purposes contemplated for the security ventilating system of the present invention and especially for adaptation to existing doors or window frames.
Accordingly, it is the principal object of the present invention to provide an improved security system applicable to an arrangement of sliding doors comprising either a single sliding door or window or a plurality of fixed and sliding doors or windows of various conventional arrangements and of a variety of heights and widths.
A more particular object of the invention is to provide a system which is simple, positive and inexpensive to install for current, or existing old installations and buildings.
A further object of the invention is to provide a security system which can be locked in place when the sliding doors or windows are opened to each of a series of different positions for the purposes of variable degrees of ventilation.
Still another object of the invention is to provide a security system which is not visible to potential intruders from the outside of the doors or windows, and which is not, therefore, readily located or removed.
Another object of the invention is to fully cope with the potential intruder's attempt to unlock, by either raising or sliding, the sliding door or window.
These and other objects are attained in a security system in accordance with the present invention which is particularly applicable to an arrangement of sliding doors or windows. Such a system comprises means adapted to be interposed into the space between the door or window jamb casing and the door or window frame when one of the group of sliding doors or windows is partially opened for ventilation; and which provides additional locking means when the doors or windows are tightly closed. This arrangement comprises a light-weight, high-strength metal lift-out grill which is constructed to be fitted into the void created when one of the sliding doors or windows is opened, the length and width of the grill varying in accordance with the size of the door or window frame. The left-hand vertical bar of the lift-out grill is secured in an auxiliary channel which is fastened along the inside edge of the left-hand door or window frame. Either the right-hand vertical bar of the grill, or alternatively, one of the series of parallel vertical bars thereof, fastens into a series of vertically aligned channels set on the inside edge of the door or window frame. Also, a horizontally directed lug fastened to each of the vertical bars is constructed to be interposed below the door or window handle to further secure the grill in place. Lastly, a strong rough-faced pin or stud is connected to a short chain or cord inside of the door frame; and said pin or stud is constructed to key into one of a series of fairly snug holes perforating the inner edge of the upper door or window corresponding to each of a series of door or window opening positions. This pin or stud passes through the upper frames of the overlapping sliding doors or windows, but does not pass through the outer edge of the door or window frame channel, so that it cannot be seen from the outside.
Another security feature designed to prevent the movable door from being lifted out of its bottom track by a screw driver or crow bar is a square metal bar or tube mounted in the top trough above the sliding door and extended beyond the maximum security opening of the door so that its mounting bolt is never available to a potential intruder. Another security feature is to have the inner flanges of the track actually extend a short distance into recesses in the lower rails of the inner and outer doors, so that the sliding doors slide along these rails. This is not, per se, a novel feature; but in common with the other features described, tends to make a burgler-proof system.
For convenience of description, the security system of the present invention is described hereinafter with reference to an arrangement consisting of one fixed door and one sliding door which is adapted to slide laterally along the inner face of the fixed door so that in completely open position, it is colinear with the fixed door. It will be understood, however, that with slight modification, the security system of the present invention may be applied to numerous variations of this arrangement. For example, the fixed and sliding doors may be reversed in direction. The arrangement may comprise a fixed door at the center with sliding doors at its opposite ends which are adapted to slide toward one another, along the inner face of the fixed door, to open. Alternatively, one sliding door may be adapted to slide along the outer face of the fixed door, and the other sliding door may be adapted to slide along the inner face of the fixed door. In still another arrangement with the fixed door in the center, the sliding doors, in open positions, may be stored in recesses in the wall, moving toward the fixed door to close. Other arrangements will occur to those skilled in the art.
These and other objects, features and advantages will be apparent to those skilled in the art when studying the specification hereinafter with reference to the attached drawings.
SHORT DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view from the left-hand corner, of the security system of the present invention, including a lift-out grill as installed in the door frame, which includes a conventional pair of rolling glass doors in partially open position.
FIG. 2 is a plan view taken along the plane 2--2 of FIG. 1 showing the door jamb casing and top portion of the rolling door-frame, together with the top edge of the lift-out grill.
FIG. 3 is a fragmentary showing in side elevation of the upper portion of FIG. 1, including perforations along the top edge of the door which are designed to receive the locking stud in different positions of the sliding door.
FIGS. 4A, 4B, and 4C show, in perspective, the principal elements added in accordance with the present invention, to the sliding door assembly, which include in FIG. 4A the lift-out grill; in FIG. 4B, the left-hand door frame grill casing; and in FIG. 4C, a series of vertically-aligned channels for the sliding door stile.
FIG. 5 is an enlarged fragmentary showing, in perspective, of the upper end of the left-hand door frame, including the left-hand door frame grill casing, as shown in FIG. 4B.
FIG. 6 is an enlarged fragmentary perspective showing of the central portion of the upper double-door channels with the rolling or sliding doors in over-lapping closed relation, and the locking stud in place.
FIG. 7 is an enlarged exploded view of a horizontal locking lug attached to one of the vertical members of the lift-out grill being moved into locking relation with the door handle.
FIGS. 8A and 8B show in perspective, and cross-section, respectively, the double-channel bottom door casing 14a, 14b of FIG. 1.
FIG. 9 shows, in section, a modification of FIG. 8B in which the central flange has been removed, and replaced by two parallel tracks which ride in longitudinal recesses in the bottom rails of the inner and outer doors, as shown in section in FIG. 10.
FIG. 11 shows in side elevation the top portion of the assemblage of FIG. 1, with the upper inside flange of the door frame partially broken away to show a rod or tube mounted in the top trough above the sliding door and extending beyond the widest security opening of the door.
FIG. 12 is an enlarged fragmentary showing in section indicated by the arrows 12-12 of FIG. 11 of the rod or tube disposed in the top rail above the slidable door.
FIGS. 13A, 13B, 13C, 13D and 13E are schematic plan views of various fixed and movable door or window arrangements to which the present security system might be applied with suitable adjustment.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 of the drawings shows the security ventilating system of the present invention, completely assembled, and in place in cooperative arrangement with a conventional pair of sliding or rolling doors 11 and 12. These are of a type used in many buildings of modern design for ingress and egress between a room at any level and an outdoor yard or patio or upper platforms. In the present example, the two doors comprising a movable door 11 and a fixed door 12, are mounted in a metal door casing 5 feet 111/4 inches in overall width and 6 feet 71/2 inches high. These are equipped with a double-channeled bottom track 14a, 14b (not shown) which is 3 11/16 inches wide; a parallel substantially aligned double-channeled top track 13a, 13b which is 31/2 inches wide (see FIG. 2); a left-hand double-track door jamb casing 15a, 15b, and a right-hand door jamb casing 16a, 16b, each 3 7/16 inches wide. The moving door 11 is 361/2 inches wide; and fixed door 12 is 36 inches wide; and both are 6 feet 7 inches high. They comprise glass panels which are respectively mounted in a pair of conventional door frames for glass doors, which may, for example, be of aluminum or stainless steel. The left-hand inner door 11 has top and bottom rails 17 and 18, which enclose the upper and lower perimeters of the double panes; and in the present example are of stainless steel, or aluminum, 361/2 inches long, 6 feet 61/2 inches in a vertical plane. The left and right-hand door stiles 19 and 20, which respectively enclose the left and right-hand edges of the panes of door 11, are also of stainless steel or aluminum, 6 feet 7 inches long in a vertical direction, 2 inches wide horizontally, and 11/8 inches thick. The outer fixed door 12 is equipped with substantially similar top and bottom rails 23 and 22, and left-hand and right-hand door stiles 21 and 24. The inner door 11 is mounted to slide or move laterally on small wheels mounted on the inside of the top and bottom tracks 13a and 14a; whereas the outer door 12 is mounted to move laterally on the top and bottom outside tracks 13b and 14b (not shown). This is better understood by referring to FIG. 2 which shows a plan view of the doors 11 and 12, with door 11 in partly open position in the upper track 13a.
The door 11 has a conventional handle 25 which projects into the interior as shown in FIG. 1, and in more detail, in FIG. 7; and which serves to move the door 11 laterally in the door frame relative to the door 12.
When the door 11 is moved to the extreme left to engage the left-hand door casing 15a in closed latching relation, there is a slight overlap between doors 11 and 12 at the center.
It is customary, in warm climates, to move the door 11 to the right to provide an opening for the purpose of ventilation. In accordance with my invention, I propose to interpose into the void between the left-hand door jamb casing 15a and the right-hand stile 19 of the door 11, a grill 31 having an overall height of 5 feet 10 inches and an overall width of 251/2 inches which is shown in detail in FIG. 4A of the drawings. In the present illustration, this comprises four vertical flat metal bars 32, 33, 34 and 35, each 5 feet 10 inches long and 3/4 inch by 1/8 inch in cross-section which are held 71/2 inches apart in a parallel fixed relation to six horizontal bars 36 (at the top) and 37, 38, 39, 40 and 41 in lower succession, each 3/4 inch by 1/8 inch in cross-section. The upper bars 36, 37 and 38 are each 12 inches apart, whereas the lower horizontal bars are spaced apart 51/2 inches along the vertical bars. Preferably, the grill 31 is made of iron or steel or high strength aluminum, which cannot be readily bent, distorted in shape or cut; and the horizontal and vertical bars are attached by, say, fillet welds or brazing. It will be understood that the grill can take numerous forms, such as rods, tee-bars, or channels.
As indicated in FIGS. 4B and 5, a vertical channel 42, which is of a suitable length and width to accommodate the left-hand bar 32 of the security grill 31, is fastened to the inside vertical edge of the left-hand door jamb casing 15a. In the present illustrative embodiment, the channel 42 is 5 feet 10 inches long, and formed of sheet metal, such as stainless steel or high-strength aluminum, 1/16 inch thick, the internal dimensions of the U-shaped channel being 1 inch across and having 3/4 inch flanges on the sides. The channel 42, the upper end of which, is shown in FIG. 4B, and in enlarged fragment in FIG. 5, connected to the left-hand door jamb 15a, is equipped along its inner edge-flange with a plurality of round openings 43, 44, 45, 46, 47 and 48. These are large enough to allow passage of a screw driver, which is used to secure a one-way self-tapping screw 49 through the corresponding screw holes in the vertical flange of channel 15a which is aligned with each of the aforesaid openings.
Referring to FIGS. 1 and 4C, there is shown a plurality of substantially identical short channels 51, 52, 53 and 54, which are installed in vertical alignment on the inner periphery of the left-hand door stile 19 of the inner, movable glass door 11. These are of a proper width to accommodate the right-hand vertical bar 35, or alternatively, each of the intermediate bars 34 and 33 of the grill 31. In the present illustration, except as to length, the general shape of the vertically-aligned channels 51, 52, 53 and 54 is substantially the same as that of the elongated left-hand channel 42, each of the short channels being 6 inches long. Each of these short channels 51, 52, 53 and 54 has near its two ends circular holes such as 55 of FIG. 7, large enough to accommodate a screw driver and screw head, and which correspond to a screw hole, such as 56, on the inner flange. The short channels 51, 52, 53 and 54 are mounted in vertical alignment along the inner left-hand edge of the door stile 19, of inner door 11, by means of one-way self-tapping screws applied through screw-holes, through the aligned openings corresponding to 55 and 56, on the outer and inner flanges of each channel. Channels 51, 52, 53 and 54 are respectively positioned along door stile 19 so that the grill 31 is held in place between channel 42, attached to the left-hand door jamb 15a, and the door stile 19, on the right. Channel 51 is centered on vertical bar 35 between the right-hand ends of horizontal bars 36 and 37; channel 52, between bars 37 and 38; channel 53, between bars 39 and 40; and channel 54, beween bars 40 and 41. Channels 51 and 52 may be combined; likewise, 53 and 54.
Fixed to the center of the right-hand vertical bar 35 of grill 31, and to the inner vertical bars 33 and 34, are three horizontal lugs 57, 58 and 59, each of which is directed to the right. These lugs are 21/2 inches long, and 3/4 inch by 1/4 inch in section, and are permanently secured to the respective vertical bars by either welding, or self-tapping, one-way screws, in the manner shown in FIG. 7 of the drawings. The lug 59 is directed to be inserted under and engage the under surface of handle 25 in the manner shown when the door 11 is moved to the opening conforming to the width of the grill 31, thereby locking the grill in position. The lugs 58 and 57 are designed to operate in a similar manner when the door 11 is moved to lesser openings, respectively engaging the vertical bars 34 and 33.
As an additional device of the security system, a single 1/8 inch, or greater, diameter rough galvanized steel nail or locking stud 60, as shown in FIGS. 1, 2 and 6, is used to secure the rolling door 11 in one to six open positions and one closed position. The stud 60 is interposed along the center line of the over-lap between the doors 11 and 12 when they are in closed position. As moving door 11 is moved to the right, the stud 60 is used to secure the door at each of a series of different openings corresponding to the holes 61, 62, 63, 64, 65, 66, and 67 of the top rail 17 of door 11, but always at the left frame of the fixed door 12; therefore, only one hole 68 is required in the inside flange of track 13a.
The outer flange of top track 13a, the top rail 17 of door 11, the inner flange of track 13a, the inner flange of track 13b and the top rail of door 12 are all drilled with holes which are horizontally aligned when doors 11 and 12 are in closed positions.
As shown in FIG. 3, in which the inside flange of channel 13a is partially broken away, the perforations 61 (not shown) and 62, 63, 64, 65, 66 and 67 of the top rail 17 of door 11 are each 3/16 inch in diameter. As door 11 is slid back and forth on track 13a, all seven of the perforations 61-65 are successively placed in alignment with the central opening 68 in the inner flange of the track 13a, and horizontally aligned openings in its outer flange, in the inner flange of track 13b, and opening 69 near the left-hand edge of door 12. It will be noted that there is no corresponding opening in the outer flange of track 13b so that the stud 60 will not be visible from the outside.
When the moving door 11 is at an opening corresponding to any one of the seven hole positions 61-67, it may be secured by the stud 60, which is securely attached to the inner wall or some other point inside of the door frame (see FIG. 1). The connecting cable 70 must be long enough so that it may be interposed through hole 69 to lock the door 11 in any of the seven positions indicated in FIG. 2. A particular feature of the stud or pin 60 is that it is of round section, and rough faced. The hole is approximately horizontal or sloping slightly downward from the inside of the room toward the outside to cause increased tightness of the pin or stud in its locking hole as the potential intruder jiggles the sliding door.
Thus, in accordance with the present illustrative embodiment of the invention, the doors 11 and 12 may be completely closed and locked with the stud 60 interposed in hole 61 in door 11 and aligned hole 69 in door 12. Alternatively, door 11 may be locked at any of the opening positions corresponding to the locking stud holes 62-67. When the grill 31 is in place at the widest secured opening, being accommodated between the channel 42 on the left-hand door frame, and the aligned channels 51, 52, 53 and 54 on the door stile 19, the hole 62 of door 11 is aligned with hole 69 of door 12 and stud 60 is fastened in place. Also, the lug 59 engages the under surface of the door handle 25. A potential intruder has no way to determine from the outside where the locking stud has been applied, or how the grill 31 is fastened in place in the door opening.
In combination with the other features of the invention, in order to prevent the movable door 11 from being lifted out of the lower double track 14a, 14b, having the form shown in FIGS. 8A, 8B, the latter can be modified in a manner shown in FIGS. 9 and 10. This is an expedient well known in the art in which the central flange of FIGS. 8A, 8B is replaced by a pair of rails 74a and 74b, which engage and ride in recesses in the lower rails 18 and 22 of the respective doors 11 and 12.
In accordance with the present invention, another device for preventing the moving door 11 from being lifted off of the track 14a is to provide a rod or tube 76, preferably of aluminum, 1/2 inch square in cross-section, which is mounted in the trough or channel 13a (see FIG. 12) approximately 10 inches from the left-hand door jamb 15a, and extending laterally to the right so that its right-hand end extends about 41/2 inches beyond the maximum security opening of door 11 which is approximately 251/2 inches. The square rod or tube 76 is designed to be secured to the inner top surface of channel 13a by a pair of upwardly projecting flat head bolts 77 and 78, each being 2 inches in from its respective end. Thus, one of the bolts is between the two doors 11 and 12, and never available to an intruder, even when the door is opened to a maximum security opening of 251/2 inches. Neither of the bolts is available to an intruder when the door is opened only 41/2 inches, or closed.
Although the invention has been described in detail with reference to a particular arrangement of glass doors mounted in a double track in which one door 12 is closed, and the other door 11 opens by moving to the right adjacent the inner surface of 12 (see FIG. 13A), it will be apparent to those skilled in the art that with slight modification, the present invention can be adapted to sliding doors of other arrangements, such as that shown in FIG. 13B in which the fixed outer door is on the left, and the sliding door moves to the left to open. In another alternative shown in FIG. 13C suitable for the system of the present invention, a fixed inner door is flanked at its two ends by a pair of sliding doors which are opened by sliding them toward one another across the inner face of the fixed door. In another alternative shown in FIG. 13D, the lateral sliding doors are opened by respectively moving them in opposite directions across the inner and outer surfaces of the fixed central door. In still another arrangement shown in FIG. 13E, the central door is fixed, and the lateral door panels are moved in opposite directions to open, away from the ends of the fixed door and into recesses in the opposite walls. It will be apparent that each of the arrangements shown are suitable for installation of the security system of the present invention, as are similar window arrangements. For example, it will be understood that more than one security grill could be used in the arrangements of FIGS. 13C, 13D and 13E in cooperation with each of the movable doors. Other arrangements will occur to those skilled in the art.
It is necessary to remove sliding doors and windows for rare occasions of repair of frames, glass, panels or their tracks. Therefore, the vertical heights of the fixed and sliding frames are shorter than the total distance from the upper edge of the lower track to the true ceiling of the upper track, thereby permitting the fixed and the sliding frames to be raised up into the extra deep upper track so that they clear the upper edge of the lower track. Then the frame can be pulled or pushed out or in, clear of its lower track; or lowered and cleared of its upper track. Thus, the frame is completely removable for any purpose such as repair, replacement or entrance by an intruder. These essential features are most commonly overlooked or not realized by occupants; but not so by potential intruders. The latter may use a strong flat tool, such as a screwdriver or tire-iron, to lift either the screwed-in-place fixed frame, or more easily, to lift the sliding frame, which is not screwed in place but only has a very small indoor latch, and which automatically unlatches when the sliding frame is lifted at the latch-end, approximately one-quarter to one-half inch.
In accordance with one prior art method, a small percentage of occupants attempt to keep intruders out by installing a stud, bolt or screw vertically in the upper track with its exposed end extending down one-quarter to one-half inch below the ceiling of this upper track at the latch-end of the sliding frame. This attempts to prevent the intruder from lifting the frame up sufficiently to unlatch the extremely small, weak latch. However, a common screwdriver can snap these latches into a non-effective shape from outdoors by prying the sliding door open, thus making stud, bolt or screw completely inaffective by sliding the door frame as previously described. A fairly common prior art practice by more knowledgeable occupants is to lay a horizontal long rod, tube or stick of wood, or the like, in the bottom track of the sliding frame to fully occupy the track length from the sliding frame to the distant wall, a length approximately equal to that of the fixed frame. Frequently such a rod, tube or stick is longer than need be, one end being raised two to six inches, so that it is more easily lifted out by the occupant and inherently seen by intruders. Some occupants also have an alternative rod, tube or stick which is four to five inches shorter to permit a ventilation opening of that width by the sliding door. One end of such a rod may be raised for ease of lifting it out.
It is possible for an intruder to counteract the above described method by using a large screwdriver or tire-iron type of tool to force the fixed frame up, and then push, or lift and push, the horizontal rod, tube or stick out of place, snap the latch of the sliding frame, and slide the latter frame fully open. Such rods, tubes or sticks are so easily seen from the outside that the intruder is encouraged to attempt to enter.
It is a particular advantage of the security locking system of the present invention, in its various disclosed ramifications, herein disclosed, that it cannot be seen from the outside by an intruder, nor is he able to use tools to lift the fixed or sliding frame from the track secured in the manner taught by the present invention.
The invention is not limited to the specific forms or dimensions shown and described by way of example, but only by the scope of the appended claims.
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A security ventilating system for an arrangement of coordinated sliding doors comprising one or more lift-out metal grills each constructed to fit between one partially opened door or window and the door or window frame at each of several different openings. For a typical arrangement in which a left-hand door opens by sliding to the right, the left-hand vertical bar of a lift-out grill is secured in a vertical channel fitted to the inside edge of the left vertical channel of the door frame. The right-hand vertical bar and several of the parallel vertical bars of the grill are designed to fasten in alternative open positions to a series of short vertically-aligned channels fastened to the left-hand stile of the partially open door. A centrally disposed horizontal stud fixed to each of the vertical bars at the different ventilation openings is constructed to engage the door handle of the open door. One additional security feature is a rough-faced nail or stud, fastened inside of the door frame to the end of a cord or chain, which keys into aligned holes along the top of the inner door frame and through the tops of the overlapping door panels corresponding to each of a plurality of openings. Other security features in combination with the invention include studs designed to extend vertically into the bottom of both the fixed and sliding doors. It is understood that the security system of this invention can be applied with suitable modifications to various arrangements of fixed and laterally sliding doors and windows.
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FIELD OF THE INVENTION
The present invention relates to radiation-curable compositions which are useful as laminating adhesives. More specifically, the present invention relates to a radiation-curable composition which is based on epoxy compounds and hydroxy-terminated polyurethanes and which exhibits excellent green strength and overall bonding capability in laminating adhesive applications.
BACKGROUND OF THE INVENTION
The flexible food packaging industry is currently experiencing relatively substantial growth due to the increasing popularity of ready-to-eat and microwaveable foods and drinks which appear to spontaneously multiply on our grocers' shelves. The flexible food packaging utilized in these popular products is typically comprised of a laminate of various polymeric films and/or metal foils. The utilization of a combination of polymeric films and metal foils allows a package to be designed so as to take advantage of the various desirable properties of the films and foils such as permeability, heat resistance and the like. The various films and foils are typically combined into a laminate by utilizing an adhesive to bond the layers of materials together.
Adhesives utilized for the manufacture of these high performance, flexible food packaging laminates have previously been based on conventional two-part urethane adhesive systems. These urethane adhesives are relatively difficult to work with since they require the mixing of two separate parts and since they typically have a limited potlife or storage capability. The urethane adhesives also typically utilize undesirable volatile organic solvents and require an extended cure cycle in order to fully develop the ultimately desired properties.
Although not previously disclosed as being useful for laminating adhesives, various photocopolymerizable compositions containing epoxy compounds have been previously described in the patent literature. For example, U.S. Pat. No. 4,256,828 discloses photocopolymerizable compositions containing epoxides, an organic material with hydroxyl functionality, and a photosensitive aromatic sulfonium or iodonium salt of a halogen-containing complex ion. The epoxide can be a cycloaliphatic epoxide while the hydroxy-functional materials can be alkanols, alkylene glycols, polyoxyalkylene glycols and triols, hydroxyl-terminated vinyl acetate copolymers, hydroxyl-terminated polyvinylacetal resins, hydroxyl-terminated polyesters, hydroxyl-terminated polylactones and hydroxyl-terminated polyalkadienes.
Another example of a photocopolymerizable epoxy-based composition is described in U.S. Pat. No. 4,593,051. This patent describes photocopolymerizable compositions based on epoxide and polymer/hydroxyl-containing organic materials. The epoxide can be a cycloaliphatic epoxide resin while the polymer/hydroxyl-containing organic materials can be polyether polyols or a polymer-polyol dispersion prepared by the free-radical polymerization of acrylonitrile or a mixture of acrylonitrile and styrene in a polyoxyalkylene polyol containing unsaturation.
Various previously described photocopolymerizable compositions such as those disclosed above have been found by the present inventors to be ineffective when utilized as a laminating adhesive for flexible packaging materials. Specifically, the previous photocopolymerizable compositions have been found to not provide a level of bond strength or green strength (the ability to adhere and firmly hold together the materials to be bonded prior to cure) acceptable for an effective utilization in flexible packaging applications.
A need therefore exists for an adhesive composition which can be utilized as a laminating adhesive in a one-part system so as to provide acceptable adhesion and potlife or storage capability. Such an adhesive composition should also exhibit sufficient green strength and should avoid the use of volatile organic solvents.
SUMMARY OF THE INVENTION
The present invention is a one-part radiation-curable adhesive composition which provides high green strength and bonding capability when utilized in laminating adhesive applications. The adhesive of the present invention exhibits instantaneous cure, has indefinite potlife and avoids the use of volatile organic solvents. Specifically, the radiation-curable composition of the present invention comprises an epoxy compound, a hydroxy-terminated polyurethane, and a photoinitiator. It has presently been discovered that the utilization of the present hydroxy-terminated polyurethanes in combination with an epoxy compound results in a radiation-curable composition which is particularly useful for bonding flexible materials in the form of a laminate.
DETAILED DESCRIPTION OF THE INVENTION
The epoxy compound of the present invention can essentially be any compound that contains an epoxy group having the formula: ##STR1## and has a viscosity of about 200 centipoise or higher at 25° C. Such materials, broadly called epoxides, include monomeric epoxides and epoxides of the polymeric type and can be aliphatic, cycloaliphatic, aromatic or heterocyclic. These materials generally have, on the average, at least 1.5 polymerizable epoxy groups per molecule (preferably two or more epoxy groups per molecule). The polymeric epoxides include linear polymers having terminal epoxy groups (e.g., a diglycidyl ether of a polyoxyalkylene glycol), polymers having skeletal oxirane units (e.g., polybutadiene polyepoxide), and polymers having pendent epoxy groups (e.g., a glycidyl methacrylate polymer or copolymer). The epoxides may be pure compounds but are generally mixtures containing one, two, or more epoxy groups per molecule. The "average" number of epoxy groups per molecule is determined by dividing the total number of epoxy groups in the epoxy-containing material by the total number of epoxy molecules present.
These epoxy-containing materials may vary from low molecular weight monomeric materials to high molecular weight polymers and may vary greatly in the nature of their backbone and substituent groups. For example, the backbone may be of any type and substituent groups thereon can be any group free of an active hydrogen atom which is reactive with an oxirane ring at room temperature. Illustrative of permissible substituent groups include halogens, ester groups, ethers, sulfonate groups, siloxane groups, nitro groups, phosphate groups, etc. The molecular weight of the epoxy-containing materials may vary from 58 to about 100,000 or more. Mixtures of various epoxy-containing materials can also be used in the compositions of this invention.
The epoxy compounds of the present invention may be cycloaliphatic epoxides. Examples of cycloaliphatic epoxides include diepoxides of cycloaliphatic esters of dicarboxylic acids such as bis(3,4-epoxycyclohexylmethyl)oxalate, bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, bis(3,4-epoxycyclohexylmethyl)pimelate, and the like. Other suitable diepoxides of cycloaliphatic esters of dicarboxylic acids are described in, for example, U.S. Pat. No. 2,750,395, which is incorporated herein by reference.
Other cycloaliphatic epoxides include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylates such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate; 3,4-epoxy-1-methylcyclohexylmethyl-3,4-epoxy-1-methylcyclohexane carboxylate; 6-methyl-3,4-epoxycyclohexylmethyl-6-methyl-3,4-epoxycyclohexane carboxylate; 3,4-epoxy-2-methylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexane carboxylate; 3,4-epoxy-3-methylcyclohexylmethyl-3,4-epoxy-3-methylcyclohexane carboxylate; 3,4-epoxy-5-methylcyclohexylmethyl-3,4-epoxy-5-methylcyclohexane carboxylate and the like. Other suitable 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylates are described in, for example, U.S. Pat. No. 2,890,194, which is incorporated herein by reference.
Cycloaliphatic epoxides are preferred, in general, for use as the epoxy compound of the present invention. Preferred cycloaliphatic epoxides for use in the invention include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate; bis(3,4-epoxycyclohexylmethyl)adipate; or mixtures thereof.
Further epoxy-containing materials which are useful in the practice of this invention include glycidyl ether monomers of the formula: ##STR2## where R' is alkyl or aryl and n is an integer of 1 to 6. Examples are glycidyl ethers of polhydric phenols obtained by reacting a polyhydric phenol with an excess of chlorohydrin such as epichlorohydrin [e.g., the diglycidyl ether of 2,2-bis(2,3-epoxypropoxyphenol)-propane]. Further examples of epoxides of this type which can be used in the practice of this invention are described in U.S. Pat. No. 3,018,262, incorporated herein by reference, and in "Handbook of Epoxy Resins" by Lee and Neville, McGraw-Hill Book Co., New York, 1967.
There are a host of commercially available epoxy-containing materials which can be used in this invention. In particular, epoxides which are readily available include octadecylene oxide, epichlorohydrin, styrene oxide, vinyl cyclohexene oxide, glycidol, glycidylmethacrylate, diglycidyl ether of bisphenol A (e.g., those available under the trade designations EPON 828, EPON 1004 and EPON 1010 from Shell Chemical Co., DER-331, DER-332, and DER-334, from Dow Chemical Co.), vinylcyclohexene dioxide (e.g., ERL-4206 from Union Carbide Corp.), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexene carboxylate (e.g., ERL-4221 from Union Carbide Corp.), 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexene carboxylate (e.g., ERL-4201 from Union Carbide Corp.), bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate (e.g. ERL-4289 from Union Carbide Corp.), bis(2,3-epoxycyclopentyl) ether (e.g., ERL-0400 from Union Carbide Corp.), aliphatic epoxy modified with polypropylene glycol (e.g., ERL-4050 and ERL-4052 from Union Carbide Corp.), dipentene dioxide (e.g., ERL-4269 from Union Carbide Corp.), epoxidized polybutadiene (e.g., OXIRON 2001 from FMC Corp.), silicone resin containing epoxy functionality, flame retardant epoxy resins (e.g., DER-580, a brominated bisphenol type epoxy resin available from Dow Chemical Co.), 1,4-butanediol diglycidyl ether of phenolformaldehyde novolak (e.g., DEN-431 and DEN-438 from Dow Chemical Co.), and resorcinol diglycidyl ether (e.g., KOPOXITE from Koppers Company, Inc.).
Still other epoxy-containing materials are copolymers of acrylic acid esters of glycidol such as glycidylacrylate and glycidylmethacrylate with one or more copolymerizable vinyl compounds. Examples of such copolymers are 1:1 styrene-glycidylmethacrylate, 1:1 methylmethacrylate-glycidylacrylate and a 62.5:24:13.5 methylmethacrylate-ethyl acrylate-glycidylmethacrylate.
The hydroxy-terminated polyurethane of the present invention is typically prepared by the reaction of at least one compound selected from the group consisting of polyesters and polyethers having a molecular weight of about 300 to about 10,000, preferably about 800 to 5,000, and having at least two hydroxy groups with less than molar amounts of a low molecular weight diisocyanate in a molar ratio of hydroxy group to isocyanate group ranging from about 1.01:1 to 3:1, preferably from about 1.2:1 to 2.2:1. Hydroxy-terminated polyurethanes are also available commercially from Lord Corporation under the tradename TYCEL.
Suitable polyesters useful for the preparation of the hydroxy-terminated polyurethanes are prepared by esterification of dicarboxylic acids or transesterification of methyl esters of dicarboxylic acids with a dihydroxy compound. Examples of suitable dicarboxylic acids are aliphatic acids such as adipic acid, glutaric acid, pimelic acid, etc.; aromatic acids such as phthalic acid, terephathalic acid, naphthalene dicarboxylic acid, etc.; cycloalkyl acids such as cyclohexane dicarboxylic acid; unsaturated acids such as maleic acid, fumaric acid, hexene dicarboxylic acid, etc.; acids containing hetero atoms such as O, S, or N, such as diglycolic acid, ethylether-2,2'-dicarboxylic acid, thiodiglycolic acid, etc.
The dihydroxy compounds useful for preparing polyesters have 2 to 8 carbon atoms and may be aliphatic such as ethylene glycol, propylene glycol, butylene-1,3-diol, butylene-1,4-diol, butylene-2,3-diol, 2,2-dimethylpropane-1,3-diol (neopentylglycol), 2,2-diethylpropane-1,3-diol, 2-methyl-2-propylpropane-1,3-diol, isomeric octanediols, etc.; unsaturated dihydroxy compounds such as heptenediol, butynediol, etc.; and dihydroxy compounds containing N, O or S hetero atoms such as diethylene glycol, triethylene glycol, thioethylene glycol, diethanolamine, N-methyl diethanolamine, etc.
The polyethers can be made in a known manner by splitting of water from a dihydroxy or trihydroxy compound of 2 to 8, particularly 2 to 4, carbon atoms or by ring opening polymerization of an alkylene oxide. The dihydroxy compounds may be the same as the compounds discussed above for the formation of polyesters. The trihydroxy compounds may be any of the trihydroxy compounds typically utilized in the preparation of polyethers. Examples of trihydroxy compounds include trimethylolyl propane, glycerol, and hexanetriol. Examples of suitable alkylene oxides are ethylene oxide, propylene oxide, tetrahydrofuran, and the like.
The low molecular weight diisocyanates may be aliphatic or aromatic and may have 6 to 40 carbon atoms. Examples of suitable diisocyanates are hexane-1,6-diisocyanate, decane-1,10-diisocyanate, diisocyanates derived from dimerized fatty acids, phenylene-1,4-diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, naphthylene-1,5-diisocyanate, diphenylmethane-4,4'-diiosycanate, diphenyl-methane-3,3'-methoxy-4,4'-diisocyanate, etc.
The epoxy compound and the hydroxy-terminated polyurethane of the invention are typically utilized in an epoxy:hydroxy functional ratio ranging from about 1:1 to 20:1, preferably from about 1:1 to 7:1.
The photoinitiator of the present invention may be any one of the well-known photoinitiators such as those described in, for example, U.S. Pat. Nos. 4,231,951; 4,256,828; 4,138,255; 4,058,401 and 4,069,055; all of which are incorporated herein by reference. Preferred photoinitiators include triarylsulfonium complex salts as described in U.S. Pat. No. 4,231,951, aromatic sulfonium or iodonium salts of halogen-containing complex ions as described in U.S. Pat. No. 4,256,828; aromatic onium salts of Group VIa elements as described in U.S. Pat. Nos. 4,058,401 and 4,138,255; aromatic onium salts of Group Va elements as described in U.S. Pat. No. 4,069,055. Such salts are commercially available as FC-508 and FC-509 (available from Minnesota Mining and Manufacturing Company), and as UVE-1014 (available from General Electric Company). The photoinitiator is typically utilized in an amount ranging from about 1 to 10, preferably from about 1 to 5, percent by weight of the radiation-curable composition.
The radiation-curable adhesives compositions of the present invention may optionally contain dyes, flow control agents, thickeners and the like, as is known in the art. The compositions are typically prepared by combining the ingredients and mixing by hand, mechanical stirrer or the like at ambient or slightly elevated temperature until a homogenous mixture is achieved.
The present radiation-curable adhesive compositions may be utilized in combination with conventional laminating machines to bond multiple layers of various materials by techniques well known in the art. One particularly useful method of applying the composition involves a process known as wet bond laminating where the adhesive composition is coated onto a polymeric film or metal foil web by a laminating machine using a gravure or smooth roll technique. The coated web is then run into a zone of ultraviolet (UV) radiation delivered by medium pressure mercury vapor lamps to initiate polymerization. The web is then laminated or nipped by a roller to a second film or foil web before polymerization is complete. Polymerization is then allowed to continue so as to bond the materials together in the form of a laminate. If one of the materials to be bonded is transparent, the two materials can be nipped or laminated with the adhesive prior to exposure to UV radiation. The UV radiation is then applied through the transparent material so as to initiate polymerization of the adhesive between the materials.
The radiation-curable adhesive compositions can be applied to essentially any material capable of receiving the compositions. The compositions are preferably utilized with film-like materials which can be adhered together in the form of a laminate. Examples of materials capable of being bonded with the present adhesive compositions include paper, cellulose hydrate or plastics, such as polyethylene, polypropylene, polyterephthalate, polyvinyl chloride, copolymers of vinylchloride and vinylidene chloride, copolymers of vinyl acetate with low olefins, polyamides, rubber hydrochloride or metal foils made of aluminum, tin, lead, copper, etc. The adhesive compositions are preferably used for the production of compound films, particularly compound films of two or more materials selected from polyethylene, polypropylene, linear polyester, aluminum, paper and cellulose hydrate.
Although preferred for use as a laminating adhesive, the adhesive composition of the present invention may also be utilized as any type of adhesive, coating, carrier vehicle, particle binder, or the like.
The following examples are provided for purposes of further illustrating the present invention and should not be construed as limiting the scope of the invention, which is defined by the claims.
EXAMPLE 1
A radiation-curable adhesive composition is prepared by combining 5.5 g of a cycloaliphatic epoxide (ERL-4221--Union Carbide Corporation), 17.2 g of a difunctional hydroxy-terminated polyurethane (TYCEL 7902--Lord Corporation), and 0.5 g of a photoinitiator (UVI 6990--Union Carbide Corporation). The resulting combination of ingredients is mixed by hand stirring to obtain a homogenous composition having an epoxy:hydroxy functional ratio of 5:1.
EXAMPLE 2
A radiation-curable adhesive composition is prepared according to Example 1 utilizing 5.2 g of the cycloaliphatic epoxide to achieve an epoxy:hydroxy functional ratio of 4:1.
The adhesive compositions of Examples 1 and 2 are utilized to bond transparent polyethylene film (SCLAIR SL1--E. I. Du Pont De Nemours & Co.) to aluminum foil. The adhesive composition is coated onto the aluminum foil at a weight of 2 lbs./ream and the coated foil is nipped to the polyethylene film by a laboratory laminator (Talboys Engineering Corporation). The resulting laminate is irradiated through the polyethylene film under two fusion lamps (300 watts/in.) in a UV curing oven (Fusion Systems, Inc.) at a belt speed of 25'/min. The resulting bonded laminate is tested for peel strength according to ASTM Test D1876-72. Testing is carried out immediately after cure, 24 hours after cure and 30 days after cure. The results are shown below in Table 1.
TABLE 1______________________________________ 24-hour PeelExample Initial Peel Strength 30-day PeelNo. Strength (lbs./in.) (lbs./in.) Strength (lbs./in.)______________________________________1 3.3 3.1 2.82 3.1 2.8 3.0______________________________________
EXAMPLE 3
A hydroxy-terminated polyurethane is prepared by reacting 125 g of diphenylmethane-4,4'-diisocyanate, 210 g of a polyether triol (TP 440, BASF Corporation) and 1020 g of a linear polyester (S1028-55, Ruco Corporation).
A radiation-curable adhesive composition is prepared by combining 1.1 g of a bisphenol-A epoxy resin (EPON 828--Shell Chemical Co.), 5.0 g of the hydroxy-terminated polyurethane resin prepared above, and 0.2 g of a photoinitiator (UVI 6990--Union Carbide Corporation). The resulting combination of ingredients is mixed by hand-stirring to obtain a homogenous composition having an epoxy:hydroxy functional ratio of 1:1. Two additional adhesive compositions are prepared in a similar manner utilizing 3.3 and 5.6 g of epoxy resin and 5.0 g and 5.0 g of hydroxy-terminated polyurethane, respectively, to achieve epoxy:hydroxy functional ratios of 3:1 and 5:1, respectively.
COMPARATIVE EXAMPLE 4
A radiation-curable adhesive composition is prepared in accordance with Example 3 except that an aromatic polyester (S1028-55--Ruco Corporation) is used as the hydroxy-functional material in lieu of the hydroxy-terminated polyurethane. The following gram amounts are utilized to achieve the corresponding epoxy:hydroxy functional ratios:
______________________________________Epoxy (g) Aromatic Polyester (g) Ratio______________________________________0.9 5.0 1:12.8 5.0 3:14.6 5.0 5:1______________________________________
COMPARATIVE EXAMPLE 5
A radiation-curable adhesive composition is prepared in accordance with Example 3 except that an aliphatic polyester (S2011-55--Ruco Corporation) is used as the hydroxy-functional material in lieu of the hydroxy-terminated polyurethane. The following gram amounts are utilized to achieve the corresponding epoxy:hydroxy functional ratios:
______________________________________Epoxy (g) Aliphatic Polyester (g) Ratio______________________________________0.9 5.0 1:12.8 5.0 3:14.6 5.0 5:1______________________________________
COMPARATIVE EXAMPLE 6
A radiation-curable adhesive composition is prepared in accordance with Example 3 except that polypropylene glycol (MW 2025) is used as the hydroxy-functional material in lieu of the hydroxy-terminated polyurethane. The following gram amounts are utilized to achieve the corresponding epoxy:hydroxy functional ratios:
______________________________________Epoxy (g) Polypropylene Glycol (g) Ratio______________________________________0.9 5.0 1:12.8 5.0 3:14.7 5.0 5:1______________________________________
The adhesive compositions of Examples 3-6 are utilized to bond transparent polyethylene film to aluminum foil in accordance with the procedure described for Examples 1 and 2. Peel strength testing is carried out immediately after cure and 3 days after cure. The results are shown below in Table 2.
TABLE 2______________________________________Peel Strength (lb./in.) Epoxy:OH Ratio 1:1 3:1 5:1 3 3 3Hydroxy Compound Initial Day Initial Day Initial Day______________________________________Example 3 2.2 3.0 3.0 3.1 3.6 3.0Comp. Example 4 2.8 2.0 1.1 0.5 0.8 0Comp. Example 5 0.4 0 0.3 0 0.5 0Comp. Example 6 0 0 0.3 0.1 0.4 0.3______________________________________
As can be seen from the above data, hydroxy-terminated polyurethanes can be utilized to produce radiation-curable compositions having surprisingly superior adhesive performance as compared to compositions based on traditional hydroxy-functional polyesters or polyethers.
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A radiation-curable composition containing an epoxy compound, a hydroxy-terminated polyurethane, and a photoinitiator. The curable composition exhibits a high green strength and excellent overall bonding capability and is particularly useful in laminating adhesive applications.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to Chinese Patent Application No. 200710166419.4, filed Oct. 31, 2007, entitled “Method for Implementing Synchronization of Link State Database, Router, Line Card and Master Board,” the content of which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
The disclosure relates to communication field, more particularly, to a method for implementing synchronization of link state database, a router, a line card, and a master board.
BACKGROUND
The characteristic of current high-level routers is that the control and forwarding are separated. Generally speaking, the inner of a router may consist of an active master board (AMB), a standby master board (SMB), and a line card (LC). The AMB and the SMB both belong to the control plane, while the LC belongs to the forwarding plane. They are connected through a switch network. As shown in FIG. 1 , it is a schematic view illustrating the structure of the conventional router. FIG. 1 shows routers A, B, and C. The process of transmitting a message from the router A to the router C is as follows: the LC 1 of the router B receives the message, e.g. a link state advertisement (LSA) message, sent from the router A; by looking up a forwarding table, when it is found out that the router C can be arrived by passing through the LC 2 , the LC 1 transmits the message to the LC 2 by the switch network; and the LC 2 directly transmits the message to the router C. The AMB does not play any role in the forwarding process, and is only responsible for collecting routing information and issuing it to the LC. The LC is only responsible for rapidly forwarding the message. The LC can support different kinds of interfaces. The forwarding table on the LC is generated according to the routing information issued by the AMB.
The control plane running on the router consists of many routing protocols. The open shortest path first (OSPF) protocol is the most widely used one. The OSPF protocol is run to store all the neighbors with the state of Full into the link state advertisement (LSA) message as link information. By the reliable transmission of the protocol, all the routers on the network may include exactly the same link state database (LSDB) and all the routers may use the same arithmetic. The routing with no loops may be obtained by calculating the same LSDB.
Currently, with regard to the application of router, there exists a non-stop routing (NSR) technique. In other words, in order to increase usability of the router, key boards (commonly, master boards) are backuped in the way of 1+1, i.e. they are stored in the AMB and the SMB. Under normal circumstances, the AMB works and the SMB dose not work. When a failure occurs, the AMB may be restarted by switching. At the same time, the SMB becomes the AMB so as to reduce the influence of the failure to the service as much as possible. If switching time is expected to be short as much as possible, the SMB needs to store the data of the AMB as much as possible. The data includes the LSDB needed for generating routing. At the moment, the LSDB stored by the SMB is required to be synchronized with the LSDB before switching as much as possible. After the switching occurs, the SMB obtains a new routing table by calculating according to the existing LSDB, so as to prevent the switching process from affecting the neighbor or the amount of service flows.
Regarding the NSR technique, one solution for implementing synchronization of the LSDB is as follows: after the LC receives a LSA message, the LC transmits the LSA message to the AMB and the SMB, simultaneously. After the SMB receives the LSA message, the SMB does not process the LSA message temporarily but caches and stores the LSA message. After the AMB receives the LSA message, the AMB starts to process the LSA message and transmits the processing result of each LSA message to the SMB. The SMB processes the cached LSA message, according to the processing result of the AMB. Therefore, when the switching occurs, after the SMB becomes a new AMB, the SMB could know that all the cached messages may not be processed by the original AMB, and the new AMB may continue to process these cached LSA messages.
Although the above mentioned technique can implement synchronization of the LSDB, it is complicated. For example, there is a need to encode all the processing manner of the LSA message for management and perform backup for all the places where the LSA message performs branch processing. All modifications for processing the LSA message, e.g. modification of codes and so on, may affect the final characteristic of implementing the NSR.
SUMMARY
The embodiments of the disclosure provide a method for implementing synchronization of LSDB, a router, a LC, and an AMB. They can implement the synchronization of the LSDB simply.
An embodiment of the disclosure provides a method for implementing synchronization of LSDB, including:
receiving a LSA message;
comparing the LSA message with a LSA message in a LSDB; updating the LSA message in the LSDB when recognizing that the LSA message received is a new message by comparing; and transmitting the LSA message received to a virtual neighbor which has established virtual neighborhood.
An embodiment of the disclosure provides a router, including:
a LC adapted to receive a LSA message, compare the LSA message received with a LSA message in a LSDB, update the LSA message in the LSDB when recognizing the LSA message received is a new message by comparing, and transmit the LSA message received to an AMB and a SMB;
an AMB adapted to receive the LSA message sent by the LC, compare the LSA message received with the LSA message in the LSDB, update the LSA message in the LSDB when recognizing that the LSA message received is a new message by comparing, and transmit the LSA message received to the SMB and other LCs except the LC of a transmitting party; and
a SMB adapted to receive the LSA message sent by the LC or the AMB which has established virtual neighborhood.
An embodiment of the disclosure provides a LC adapted to receive a LSA message, compare the LSA message received with a LSA message in a LSDB, update the LSA message in the LSDB when recognizing the LSA message received is a new message by comparing, and transmit the LSA message received to an AMB and a SMB; and
An embodiment of the disclosure provides an AMB adapted to receive the LSA message sent by the LC, compare the LSA message received with the LSA message in the LSDB, update the LSA message in the LSDB when recognizing that the LSA message received is a new message by comparing, and transmit the LSA message received to the SMB and other LCs except the LC of a transmitting party.
The embodiments of the disclosure include: receiving a LSA message; comparing the LSA message with a LSA message in an LSDB, updating the LSA message in the LSDB when recognizing that the LSA message received is a new message by comparing, and transmitting the LSA message received to a virtual neighbor which has established virtual neighborhood. In the technical solution of embodiments of the disclosure, the virtual neighborhood has already been established between component units in the router and the LSDB has been distributedly stored. After receiving the LSA message, a step of comparing with the stored LSA message is added. Only when it is recognized by comparing that the received LSA message is a new LSA message, will the LSA message be sent to the virtual neighbor which has established virtual neighborhood. Therefore, the synchronization of the LSDB is simply implemented by adopting the LSDB synchronization mechanism of the OSPF protocol's own, which greatly reduces the amount of message flow inside the router.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view illustrating the structure of a conventional router;
FIG. 2 is a schematic view illustrating the process of the synchronization of the LSDB between the MB and the LC, in accordance with an embodiment of disclosure;
FIG. 3 is a flow chart illustrating the process that the LC receives the LSA message and synchronizes the LSDB to the virtual neighbor, in accordance with an embodiment of the disclosure;
FIG. 4 is a flow chart illustrating the process that the AMB receives the LSA message and synchronizes the LSDB to the virtual neighbor, in accordance with an embodiment of the disclosure;
FIG. 5 is a schematic view illustrating the structure of the router, in accordance with an embodiment of the disclosure;
FIG. 6 is a schematic view illustrating the structure of the LC in the router, in accordance with an embodiment of the disclosure;
FIG. 7 is a schematic view illustrating the structure of the AMB in the router, in accordance with to an embodiment of the disclosure; and
FIG. 8 is a schematic view illustrating the structure of the SMB in the router, in accordance with an embodiment of the disclosure.
DETAILED DESCRIPTION
The embodiments of the disclosure provide a method for implementing the synchronization of LSDB. This method can implement the synchronization of LSDB simply and has strong expandability.
When the OSPF protocol is running, there exists a designated router (DR), a backup designated router (BDR) and a non-designated router (DR Other). The DR and the BDR need to be elected in network. Once the DR has failure, the BDR as a backup of the DR may turn to be a DR so that the network can continue working. Compared with the DR and the BDR, other non-DRs and non-BDRs all can be called DR Other.
In the method of embodiments of the disclosure, the AMB is taken as the DR, the SMB is taken as the BDR, and the LC is taken as the DR Other. In other words, each of the AMB, SMB and LC inside the router is taken as a single router. They form virtual neighborhood and perform the synchronization of the LSDB in accordance with a synchronization mechanism of the OSPF protocol. At this moment, without election by the DR and the BDR, the AMB may be directly considered as the DR and the SMB may be directly considered as the BDR. Alternatively, the AMB is taken as the BDR and the SMB is taken as the DR. However, the LC should be taken as the DR Other. In addition, the actual interface state and the neighbor state with an outer router are also processed by the LC. The AMB may generate a LSA message but the SMB does not generate any LSA message. With regard to the DR, the DR forms virtual neighborhood with each LC, the interface state and the neighbor state between the DR and the outer router are obtained from the LC, and the related configuration is directly backuped into the BDR. With regard to the BDR, similar to the DR, the BSR forms virtual neighborhood with the LC, and the interface state and the neighbor state between the DR and the outer router are obtained from the LC. With regard to the DR Other, each LC may be called the DR Other. The LC preserves a complete link state database (LSDB) in local. This LSDB is a universal set of the LSDB sent to the LC from all the virtual neighbors associated with the LC. In prior art, the LSDB is stored in the MB. In the method in accordance with embodiments of the disclosure, the LSDB is also stored in the LC, that is, the LSDB is distributed in different LCs. Each of LCs stores the related part of the LSDB, and then transmits it to the AMB and the SMB for collection. Therefore, the LSDB may be called distributed LSDB. Only after the LC received the updated LSA message, it transmits the LSA message to the DR and the BDR.
In the embodiments of the disclosure, each of the AMB, SMB, and LC inside the router is regarded as a single virtual router, and they form virtual neighborhood. Therefore, there is a need to create a virtual interface on the MB (including the AMB and the SMB) and the LC, respectively, and establish the virtual neighborhood. Concerning the actual interface state and neighbor state with the outer router, they may be established with the outer router via the LC. The specific process is similar to the original process of establishment with the outer router via the MB except the process is implemented by the LC instead. Therefore, unnecessary details will not be described here. Accordingly, the LC may manage the virtual interface and the virtual neighborhood with the AMB and the SMB and the interface and neighborhood with the outer router and the LC at the same time. The virtual neighborhood established between the MB and the LC is created following rules of the OSPF protocol. There may be two manner. The first manner is to implement the establishment of the virtual neighborhood by using the process of neighbor establishment stipulated by the protocol. The MB and the LC transmit Hello messages (OSPF neighbor discovery messages) mutually. After receiving the Hello message, the MB and the LC transmit DD messages (OSPF database description messages) mutually and request opposite party to transmit the LSA message needed according to the DD messages, so as to create the virtual neighbor in Full state. The second manner omits the process of transmitting the Hello messages and the DD messages. The MB and the LC may directly get to know the existence of the opposite party according to the provided device management information, and directly transmit the LSA message mutually, so as to create the virtual neighbor in Full state.
Each manner for creating the virtual neighbor mentioned above needs a virtual interface corresponding to the LC or the MB to be set for every area. For example, if there are 500 areas on one LC, the LC and the MB both need to create a corresponding virtual interface for each area. Too many virtual interfaces may cause the ASE LSA message (the fifth-type LSA message) flood all over the virtual interfaces, which results in a certain waste. Therefore, it may be further optimized. Not every area has a set of virtual interfaces created corresponding to the LC and the MB. Instead, only one virtual interface which can process the messages in all areas is created on the LC or the MB. It should be noted that, in the method of the embodiments of the disclosure, the valid LSA message (e.g. the ninth-type LSA message) in the local interface needs to be switched by the MB and the LC, but no longer forwarding of the valid LSA message after being received by the interface, according to the OSPF protocol, needs to be avoided because the conventional LSDB is directly stored in the MB and the LC in the embodiments of the disclosure needs to synchronize its own LSDB to the LSDB on the MB.
The process of implementing the synchronization of the LSDB between the MB and the LC by using the characteristic of the OSPF protocol in the method of the embodiments of the disclosure is described in detail as follows.
As shown in FIG. 2 , it is a schematic view illustrating the process of the synchronization of the LSDB between the MB and the LC, in accordance with an embodiment of disclosure. As shown in FIG. 2 , the synchronization is ensured through a retransmission mechanism between the AMB and the LC. There are many retransmission queues (each retransmission queue corresponds to one LC) on the AMB. There are two retransmission queues (the two retransmission queues correspond to the AMB and the SMB) on the LC. Regarding the SMB, it only receives the LSA message sent by the AMB or the LC and returns an acknowledgement (ACK) message with no LSA message generated. There is difference among the OSPF protocols running on the AMB, the SMB, and the LC. The AMB may generate a new LSA message, which performs aging and refreshment of the LSA message. The SMB and the LC do not perform the aging and refreshment of the LSA message, and maintain their own LSDB by the AMB. The routing calculation is only performed on the AMB, but not on the SMB and the LC.
The LC synchronizes its own LSDB to the AMB and the SMB. After the LC receives a LSA message, the LC performs comparison between the received LSA message and the LSA message in the LSDB stored in the LC itself to recognize whether it is new or old. The above mentioned comparison may be performed, according to a conventional arithmetic in the OSPF standard protocol. For example, the comparison may be performed according to the sequence number, checksum, or age of the LSA message. The message with greater sequence number, greater checksum, or greater age is the new message. The messages with contrary condition are the old message. When the received LSA message is old or the same, it is processed according to the protocol. When the received LSA message is new, it is used to update the stored LSA message. The new LSA message is packed as the size of MTU (IP Maximum Transmission Unit) and the packed LSA message is added into the retransmission queue sent to the AMB and the SMB. The new LSA message is sent to the AMB and the SMB in a way of multi-broadcasting. After the LC receives the ACK message returned by the AMB and the SMB, the LC deletes the LSA message in the corresponding retransmission queue. After the AMB receives the LSA message, the AMB also compares it with the LSA message in the LSDB stored by itself to recognize whether it is new or old. If the received LSA message is the same LSA message, the AMB returns the ACK message to the LC. If the received LSA message is a new LSA message, the AMB updates the stored LSA message and transmits the new LSA message to other interface boards (including the SMB and other LC). If the received LSA message is an old LSA message, the AMB transmits the stored new LSA message to the LC. The AMB transmits the LSA message to the LC (including the LC of the transmitting party and other LCs) also through a retransmission queue. It can be seen that, this mechanism can totally ensure the synchronization of the distributed LSDB.
Taking the situation that the LC receives the LSA message and synchronizes the LSDB to the virtual neighbor as an example, the detail is explained as follows.
As shown in FIG. 3 , it is a flow chart illustrating the process that the LC receives the LSA message and synchronizes the LSDB to the virtual neighbor, in accordance with an embodiment of the disclosure, including the following steps:
Step 301 : The LC compares the received LSA message with the stored LSA message in the LSDB. If the received LSA message is the same as the stored LSA message, Step 302 is executed. If the received LSA message is older than the stored LSA message, Step 303 is executed. If the received LSA message is newer than the stored LSA message, Step 304 is executed.
It should be noted that the LSA message received by the LC may be sent by an outer router or by an AMB.
Step 302 : The LC returns an ACK message to the transmitting party.
Step 303 : The LC forwards the stored LSA message to other outer routers.
Step 304 : The LC updates the stored LSA message. If the received new LSA message is sent by the outer router, the LC adds the new LSA message into a virtual neighbor retransmission queue of the corresponding AMB and SMB. The LC may transmit the new LSA message to the AMB and the SMB in a way of multi-broadcasting. If the received new LSA message is sent by the AMB, the LC may transmit the new LSA message to the SMB and other outer routers in the way of multi-broadcasting, and Step 305 is executed.
When the LSA message is sent to the AMB or the SMB, the LSA message is packed as the size of a MTU and the packed LSA message is added into the retransmission queue sent to the AMB and the SMB. The message headers of the ASE LSA message (the fifth-type LSA message) and the Opaque10 LSA message (the tenth-type LSA message) contain process numbers. The message headers of the Router LSA message (the first-type LSA message), the Network LSA message (the second-type LSA message), and the Summary LSA message (the third-type LSA message) contain process numbers and area numbers. The LSA messages in interface scope also contain interface indexes.
Step 305 : After the LC receives the ACK message of the AMB, the LC deletes the LSA message in the corresponding retransmission queue. After receiving the ACK message of the SMB, the LC deletes the LSA message in the corresponding retransmission queue. If the LC does not receive the ACK message of the AMB or the SMB, the LC retransmits the LSA message in the corresponding retransmission queue to the corresponding AMB or SMB in a way of unicasting, after a retransmission timer expires.
In addition, when the interface state or the neighbor state between the LC and the outer router is changed, the LC notifies the AMB and the SMB so as to enable the AMB and the SMB to acquire the newest interface state or neighbor state.
Taking the situation that the AMB receives the LSA message and synchronizes the LSDB to the virtual neighbor as another example, the detail is described as follows.
As shown in FIG. 4 , it is a flow chart illustrating the process that the AMB receives the LSA message and synchronizes the LSDB to the virtual neighbor, according to an embodiment of the disclosure, including following steps:
Step 401 : The AMB compares the received LSA message with the LSA message in the LSDB stored. If the received LSA message is the same as the stored LSA message, Step 402 is executed. If the received LSA message is older than the stored LSA message, Step 403 is executed. If the received LSA message is newer than the stored LSA message, Step 404 is executed.
Step 402 : The AMB returns an ACK message to the LC of the corresponding transmitting party.
Step 403 : The AMB adds the stored LSA message to the virtual neighbor retransmission queue of the corresponding LC of the transmitting party, transmits the stored LSA message to the LC of the transmitting party, and executes Step 405 ;
Step 404 : The AMB updates the stored LSA message, transmits the new LSA message to other interface boards (including the SMB and other LCs), and executes Step 405 .
The AMB also adds the new LSA message into the virtual neighbor retransmission queue of other LCs and transmits the new LSA message to other LCs, except the LC of the transmitting party.
Step 405 : After the AMB receives the ACK message returned by the LC, the AMB deletes the LSA message in the corresponding retransmission queue. If the AMB does not receive the ACK message returned by the LC, the AMB retransmits the LSA message in the corresponding retransmission queue to the corresponding LC after the retransmission timer expires.
It should be noted that, after the AMB generates a new LSA message, the AMB directly transmits the new LSA message to the SMB and all the LCs. When the new LSA message is sent to the LC, the LSA message is added into the virtual neighbor retransmission queue of the corresponding LC and sent to the LC. If the AMB receives the ACK message returned by the LC, the AMB deletes the LSA message of the corresponding retransmission queue. If the AMB does not receive the ACK message returned by the LC, the AMB retransmits the LSA message in the corresponding retransmission queue to the corresponding LC, after the retransmission timer expires.
The introduction mentioned above is for the processes that the LC and the AMB receive the LSA message and synchronize the LSDB to the virtual neighbor, respectively. With regard to the SMB, it only receives and stores the LSA message, and then returns the ACK message to the transmitting party, but the SMB does not transmit out the LSA message. The LC does not transmit the received LSA message to the AMB and the SMB unless the received LSA message is new. The AMB also does not transmit the received LSA message to the SMB and other LCs unless the received LSA message is new. Alternatively, when the AMB generates a new LSA message, the AMB directly transmits the new LSA message to the SMB and all the LCs. Therefore, generally speaking, all the LSA messages received by the SMB are new. What the SMB needs to do is just to receive and store the LSA messages, and then return the ACK message to the transmitting party.
It should be noted that, if a SMB is newly inserted, the SMB creates a virtual interface and a virtual neighbor corresponding to the AMB and the LCs, and takes the AMB as the DR. Then, all the LCs and AMB start to transmit its own LSA messages to the SMB. If a LC is newly inserted, the LC creates a virtual interface and a virtual neighbor corresponding to the AMB and the SMB, and takes the AMB as the DR. Then, the AMB and the SMB start to transmit all the LSA messages to the LC. In addition, the newly inserted LC establishes a neighborhood with the outer router. Because the virtual neighbor and the virtual interface are established between the LC and the MB, once a new LC is inserted, the MB and the LC can both obtain the processing functions of the corresponding virtual neighbor. In addition, the actual interface state and the neighbor state with the outer router may be also implemented via the LC so that if each LC can support 100 neighbors, 10 LCs can support 1000 neighbors accordingly. Therefore, the expandability is good.
The synchronization of the LSDB performed in accordance with the above manner can guarantee the synchronization of the LSDB between the AMB, the SMB, and the LC, which can greatly reduce the amount of message flow between the AMB, the SMB, and the LC. Because the LSDB is stored on the LC, no matter in the process of establishing the neighbor or in the process of synchronizing the LSDB, the AMB needs to participate in the processing only when a LSA message newer than on the LC is processed or a newer LSA message is required. After receiving the same or the old LSA message or a request, the LSA message can be processed independently on the LC without participation of the AMB. The method in accordance with the embodiments of the disclosure fully takes advantage a LSDB synchronization mechanism of the OSPF's own so that the method can be implemented simply and reliably.
When a switching occurs and the SMB is taken as an AMB, the LC takes the new AMB as the DR. Because each LC stores the LSDB by itself in the method in accordance with embodiments of the disclosure, after the switching, the new AMB may directly obtain the LSDBs on all the LCs. Besides, after the switching occurs, the switching of the AMB will not cause any change for the neighbor state on the LC because the interface state and the neighbor state are stored by the LC. Therefore, the new AMB may directly obtain the interface state and the neighbor state on each of LCs. Therefore, the new AMB may obtain the LSDB and the relationship between the interface state and the neighbor state on the LC from the LC and implement synchronization of the LSDB after switching. Then, the new AMB performs routing calculation once, according to the LSDB and the neighborhood, and then updates the routing table.
It should be noted that, the above content is explained as an example under a situation of 1+1 backup, i.e. one AMB and one SMB. Under a situation of 1+N backup, i.e. one AMB and N SMBs, the content may also be implemented simply because the SMB does not generate any LSA message. The principle is the same only by regarding all the SMBs as the BDRs.
It should be further explained that the methods in accordance with the embodiments of the disclosure take the running of the OSPF protocol as an example, but should not be limited to it. Besides, the methods may also be adopted in other protocols for example in an Intermediate System to Intermediate System (IS-IS) protocol, which is quite similar to the OSPF protocol.
The methods for implementing the synchronization of the LSDB in accordance with the embodiments of the disclosure are described in more detail as the above mentioned. Correspondingly, an embodiment of the disclosure provides a router.
As shown in FIG. 5 , it is a schematic view illustrating the structure of the router, in accordance with the embodiment of the disclosure.
As shown in FIG. 5 , the router includes a LC 501 , a LC 502 , an AMB 503 , and a SMB 504 . It should be noted that two LCs are only taken as an example in FIG. 5 .
In the embodiment of the disclosure, the AMB is taken as the DR, the SMB is taken as the BDR and the LC is taken as the DR Other; in other words, each of the AMB, SMB, and LC inside the router is taken as one single router. They form a virtual neighborhood, and perform the synchronization of the LSDB, according to the synchronization mechanism of the OSPF protocol. At this moment, there is no need to elect the DR and the BDR. The AMB may be directly taken as the DR, and the SMB may be directly taken as the BDR. Alternatively, the AMB may be taken as the BDR, and the SMB may be taken as the DR. However, the LC should be taken as the DR Other.
The LC is adapted to receive the LSA message, compare the received LSA message with the LSA message in the LSDB stored, update the LSA message in the LSDB stored when recognize that the received LSA message is a new message by comparing, and transmit the received LSA message to the AMB 503 and the SMB 504 .
The AMB 503 is adapted to receive LSA message sent by the LC, compare the received LSA message with the LSA message in the LSDB stored, update the LSA message in the LSDB stored when recognize that the received LSA message is a new message by comparing, and transmit the received LSA message to the SMB 504 and other LCs, except the LC of the transmitting party.
The SMB 504 is adapted to receive the LSA message sent by the virtual neighbor LC or the AMB 503 , which has established the virtual neighborhood.
As shown in FIG. 6 , it is a schematic view illustrating the structure of the LC in the router, according to an embodiment of the disclosure.
The LC includes a comparing unit 601 , a first processing unit 602 , a second processing unit 603 , a third processing unit 604 , and a virtual neighborhood creating unit 605 .
The comparing unit 601 is adapted to compare the receive LSA message with the LSA message stored in the LSDB, after receiving the LSA message. The LSA message received by the comparing unit 601 may be sent by other routers or by the AMB of the present router.
The first processing unit 602 is adapted to update the LSA message in the LSDB stored after the comparing unit 601 recognizes that the LSA message received is a new message by comparing, transmit the received LSA message to the AMB and the SMB if the received new LSA message is sent by the outer router, and transmit the received LSA message to the SMB and other outer routers in the way of multi-broadcasting if the received new LSA message is sent by the AMB. The first processing unit 602 of the LC transmitting the received LSA message to the AMB and the SMB specifically includes: adding the received LSA message into the retransmission queue of the corresponding AMB and SMB, and transmitting the received LSA message to the AMB and the SMB in the way of multi-broadcasting; if a returned ACK message is received, deleting the LSA message in the corresponding retransmission queue; if no returned ACK message is received, retransmitting the LSA message in the corresponding retransmission queue in the way of unicasting after the retransmission timer expires.
The second processing unit 603 is adapted to transmit the LSA message in the LSDB stored to other routers, after the comparing unit 601 recognizes that the received LSA message is an old message by comparing.
The third processing unit 604 is adapted to return an ACK message to the transmitting party, after the comparing unit 601 recognizes that the LSA message received is a same message by comparing.
The virtual neighborhood creating unit 605 is adapted to create a virtual interface and establish virtual neighborhood with the AMB 503 and the SMB 504 via the virtual interface.
As shown in FIG. 7 , it is a schematic view illustrating the structure of the AMB in the router, according to an embodiment of the disclosure.
The AMB 503 includes a comparing unit 701 , a first processing unit 702 , a second processing unit 703 , a third processing unit 704 , and a virtual neighborhood creating unit 705 .
The comparing unit 701 is adapted to compare, after receiving the LSA message sent by the LC, the received LSA message with the LSA message in the LSDB stored.
The first processing unit 702 is adapted to update the LSA message in the LSDB stored when the comparing unit 701 recognizes that the LSA message received is a new message by comparing, and transmit the received LSA message to the SMB and other LCs, except the LC of the transmitting party.
The second processing unit 703 is adapted to transmit the LSA message in the LSDB stored to the LC of the transmitting party, when the comparing unit 701 recognizes that the LSA message received is an old message by comparing.
The first processing unit 702 or the second processing unit 703 of the AMB transmitting the LSA message to the LC specifically includes: adding the LSA message into the retransmission queue of the corresponding LC and transmitting the LSA message to the LC; if a returned ACK message is received, deleting the LSA message in the corresponding retransmission queue; and if no returned ACK message is received, retransmitting LSA message in the corresponding retransmission queue after the retransmission timer expires.
The third processing unit 704 is adapted to return an ACK message to the LC of the transmitting party, when the comparing unit 701 recognizes that the LSA message received is a same message by comparing.
The virtual neighborhood creating unit 705 is adapted to create a virtual interface and establish the virtual neighborhood with the LC and the SMB 504 via the virtual interface.
The AMB 503 further includes a generating unit 706 .
The generating unit 706 is adapted to generate a LSA message and transmit the LSA message generated to the SMB and all the LCs. The transmission to the LC specifically includes: adding the LSA message into the retransmission queue of the corresponding LC and transmitting the LSA message to the LC; if a returned ACK message is received, deleting the LSA message in the corresponding retransmission queue; if no returned ACK message is received, retransmitting the LSA message in the corresponding retransmission queue after the retransmission timer expires.
As shown in FIG. 8 , it is a schematic view illustrating the structure of the SMB in the router, according to an embodiment of the disclosure.
The SMB includes a receiving unit 801 , a processing unit 802 , and a virtual neighborhood creating unit 803 .
The receiving unit 801 is adapted to receive the LSA message sent by the LC or the AMB as the virtual neighbor, which has established virtual neighborhood. The processing unit 802 is adapted to obtain the LSDB and the relationship between the interface state and neighbor state stored in the LC from the virtual neighbor LC, when a switching occurs and the SMB becomes the new AMB. The virtual neighborhood creating unit 803 is adapted to create a virtual interface and establish the virtual neighborhood with the LC and AMB 503 via the virtual interface.
After the switching occurs, because the interface state and the neighbor state are stored in the LC, the switching of AMBs will not cause any change for the neighbor state on the LC. When the SMB becomes the new AMB, the processing unit 802 of the SMB may directly obtain the interface state and neighbor state on each LC and then perform routing calculation once according to the LSDB, and update the routing table.
In a word, the technical solution of embodiments of the disclosure is: receiving a LSA message; comparing the LSA message with a LSA in an LSDB; when it recognizes that the received LSA message is a new message by comparing, updating the LSA message in the LSDB and transmitting the received LSA message to a virtual neighbor which has already established virtual neighborhood. In the technical solution of embodiments of the disclosure, the virtual neighborhood has already been established between component units in the router and the LSDB has been distributedly stored. After receiving the LSA message, a step of comparing with the stored LSA message is added. Only when it is recognized by comparing that the received LSA message is a new LSA message, will the LSA message be sent to the virtual neighbor which has established virtual neighborhood. Therefore, the synchronization of the LSDB is simply implemented by adopting the LSDB synchronization mechanism of the OSPF protocol's own, and which greatly reduces the amount of message flow inside the router.
Furthermore, because the LSDB is stored on the LC, no matter in the process of establishing the virtual neighbor or in the process of synchronizing the LSDB, the AMB needs to participate in the processing only when a LSA message newer than that on the LC is processed or a newer LSA message is required. After receiving the same or the old LSA message or a request, the LSA message can be processed independently on the LC without participation of the AMB.
In addition, if switching occurs, the SMB is taken as a new AMB and the LC takes the new AMB as the DR. Because each of LCs stores the LSDB respectively, after switching, the new AMB may be able to directly obtain the LSDBs on all the LCs. Besides, because the interface state and the neighbor state are stored in the LC, the switching of AMBs will not cause any change for the neighbor state on the LC so that the new AMB may directly obtain the interface state and the neighbor state on each LC. Therefore, the new AMB implements synchronization of the switched LSDB, according to the LSDB and relationship between the interface state and the neighbor state on the LC obtained from the LC. Furthermore, when a new LC is inserted, it may be implemented to support more neighbors.
Finally, it should be understood that the above embodiments are only used to explain, but not to limit the technical solution of the disclosure. Despite the detailed description of the disclosure with referring to above preferred embodiments, it should be understood that various modifications, changes or equivalent replacements can be made by those skilled in the art without departing from the spirit and scope of the disclosure and covered in the claims of the disclosure.
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A router is provided including a line card (LC), an active master board (AMB), a standby master board (SMB) and a LC for implementing a simple synchronization of a link state database (LSDB).
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RELATED APPLICATION
[0001] This application claims the priority benefit of U.S. application Ser. No. 13/113,574 filed on May 23, 2011, which claims the priority benefit of provisional application Ser. No. 61/347,391 filed on May 22, 2010. The disclosures of the foregoing U.S. patent applications are specifically incorporated herein by this reference in their entirety and are assigned to STMicroelectronics, Inc., assignee of the present invention.
FIELD OF THE INVENTION
[0002] This invention relates to a method of saving power in wireless network devices, and more specifically, to a method of transmitting frames and switching the power saving mode of WGA network devices.
BACKGROUND OF THE INVENTION
[0003] The Wireless Gigabit Alliance (WGA) Draft Specification 0.8 (WGA-D08), January 2010, herein incorporated by reference, defines modifications to both the 802.11 physical layers (PHY) and the 802.11 Medium Access Control Layer (MAC) to enable operation in the 60 GHz frequency bank (mmWave) for very high throughput wireless networks.
[0004] The personal basic service set (PBSS) is a self-contained network which includes one PBSS control point (PCP) and other stations (STAs). Wireless communication is possible to all member STAs of the PBSS. The infrastructure BSS is a network which includes one access point (AP) and set of stations (STAs) that have successfully synchronized with the AP using the JOIN service primitives and one STA that has used the START primitive. Membership in a BSS does not imply that wireless communication with all other members of the BSS is possible. An AP in BSS serves as gateway to access another network, e.g., the Internet.
[0005] Section 9.23 of WGA-D08 defines the mmWave channel access. Channel access by a mmWave station (mSTA) during the Beacon Intervals (BI) and is coordinated by a schedule. The schedule of the data transfer time (DTT) of a BI is communicated through the Extended Schedule element in the Announce frame or the mmWave Beacon frame. The Extended Schedule element contains the scheduling information of all allocations in the DTT.
[0006] FIG. 1 shows an example BI structure as defined in WGA-D08. In a BI, the DTT is an access period during which frame exchanges are performed between STAs. The DTT is comprised of the contention-based access periods (CBPs) and service periods (SPs). SPs are allocated to specific transmitting and receiving STAs, and CBPs are not specifically allocated to any STA.
[0007] Section 11.2 of WGA-D08 defines power management modes for a wireless device working under mmWave channels. Table 44 lists the various power states for PCP and non-PCP STAs during the various access periods of an Awake BI.
[0000]
TABLE 44
Power management states for an
Awake BI (selected portions reproduced).
PS non-PCP
BI Portion
PPS PCP
STA
CBP marked as PCP available
Awake
Awake
in the schedule
Doze
CBP marked as PCP unavailable
Doze
Awake
in the schedule
Doze
SP with broadcast AID as Destination AID
Awake
Awake
Non-truncatable or non-extensible SP with
Awake
Awake
non-PCP STA (excluding the PS STA) as
Doze
Doze
Source AID and Destination AID
Truncatable SP or extensible SP with
Awake
Awake
non-PCP STA (excluding the PS STA) as
Doze
Source AID and Destination AID
SPs allocated to itself
Awake
Awake
All other SPs
Awake
Awake
Doze
Doze
[0008] However, the power management states are generically defined. There are many inefficiencies when working together with transmitting frames. Thus, there is a need for optimizing the switching of power management modes and transmitting frames.
[0009] Further, a mSTA may additionally work in an infrastructure BSS beyond the PBSS. An infrastructure BSS contains an AP providing access to another network, e.g., the Internet. All STAs within an infrastructure are required to be associated with the AP. WGA-D08 does not define a power saving mechanism for the infrastructure BSS; therefore, only 802.11 baseline power saving mechanism will be used in 60 GHz infrastructure BSS. Thus, there is a further need to implement a power saving mechanism for mSTAs that can work with both PBSS and 802.11 baseline power saving mechanisms.
SUMMARY OF THE INVENTION
[0010] The present invention is directed to a method of saving power in wireless network devices by switching power saving modes and transmitting frames of a BI.
[0011] In one embodiment of the present invention, stations can switch to awake during a CBP. Stations can further eliminate an Announcement Traffic Indication Message (ATIM) frame from the BI.
[0012] In another embodiment of the present invention, stations in a group can schedule a group address frame to be sent during the CBP and group address SP of an active group BI when all stations in the group are in active mode.
[0013] In yet another embodiment of the present invention, stations can change the transmission of frames during a SP to allow for the assigned service period receiver to transmit to the assigned service period initiator.
[0014] In further yet another embodiment of the present invention, stations in peer-to-peer connection can directly notify their peer stations upon switching back to active mode after switching to doze mode of its wakeup schedule and power saving mode.
[0015] In another embodiment of the present invention, stations of an infrastructure BSS may use the same method of saving power as stations of a PBSS noting a difference where each BI is AP's awake BI.
[0016] The foregoing and other features, utilities and advantages of the invention will be apparent from the following more particular description of an embodiment of the invention as illustrated in the accompanying drawings.
[0017] In addition, the features and advantages described in this disclosure and in the following detailed description are not all-inclusive. Many additional features and advantages will be apparent to one of ordinary skill in the relevant art in view of the drawings, specification, and claims hereof. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes and may not have been selected to delineate or circumscribe the inventive subject matter; reference to the claims is necessary to determine such inventive subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 shows the BI structure as defined in WGA-D08;
[0019] FIG. 2 shows a Delivery Traffic Indication Message (DTIM) BI with a group address frame in a CBP according to another embodiment of the invention;
[0020] FIG. 3 shows a BI with a SP according to another embodiment of the invention; and
[0021] FIGS. 4A and 4B show a PBSS under direct peer notification according to another embodiment of the invention.
DETAILED DESCRIPTION
[0022] Embodiments of the present invention are hereafter described in detail with reference to the accompanying figures. Although the invention has been described and illustrated with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the combination and arrangement of parts can be resorted to by those skilled in the art without departing from the spirit and scope of the invention.
[0023] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the present invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[0024] The invention relates to a novel method for saving power in wireless network devices. Embodiments of the invention are directed towards saving power in WGA network devices by re-scheduling communication frames and switching power saving modes for periods of inactivity. The method has added advantages of reducing retransmission, increasing the duration of the doze state for a device, and other advantages that may be learned in practice by one of ordinary skill in the art.
[0025] An active STA or a power save STA in its awake BI is switched to the active power management state during all CBP periods according to one embodiment of the invention.
[0026] Referring to Table 44, a STA in active mode and a power save STA in its awake BI can switch to doze mode in an awake BI during the CBP for a non-PCP STA. If a STA, e.g., STA1, transmits frames in a CBP to another STA in active mode, e.g., STA2, the frame transmission cannot be received correctly by STA2 if STA2 is in doze state. STA1 may have to retransmit frames several times before the frames are received correctly by STA2, thereby wasting power.
[0027] Section 11.2.3.1.3 of WGA-D08 further defines an Announcement Traffic Indication Message (ATIM) frame for an ATIM sender to notify that there are buffered frames for ATIM destination. Before transmitting frames to a STA in active mode in the CBP, a directed ATIM frame to the active STA may be required. This is not a good requirement, as explained in the following example. In each BI, a STA, e.g., STA1, needs to send an ATIM frame to each STA, e.g., STA2, for which STA1 has buffered frames in active mode so that STA2 will be awake in the CBPs. This makes the CBP transmission complicated. However, if the protocol mandates that each active STA is to be awake in each CBP, then if a STA has frames for an active STA, it can transmit frames to the active STA in each CBP without transmitting ATIM to the active STA.
[0028] Therefore, by mandating an active STA to be in awake state during all CBP periods, the complexity of power management is reduced by eliminating the need of transmitting the directed ATIM frame to the active STA before transmitting frames to a STA in an active mode in the CBP. The result is increased bandwidth and power saving as well as simplifying the CBP frame transmission protocol.
[0029] FIG. 2 shows a DTIM BI with a group address frame in a CBP or SP according to another embodiment of the invention.
[0030] Group address frames are multiple destination broadcast frames that a STA can send to a group of STAs in its group SP or a CBP in its active BIs. However, with power saving mode considerations, other STAs may be in doze mode during such BIs. Thus, other STAs may not receive the group address frame sent by the STA. In other words, if a STA wants to receive group address frames, it has to be active in each BI. This is not good for saving power, thus a need for improvement exists.
[0031] Specific periodic BI is defined according to one embodiment of the invention. During such BIs, group address frames can be transmitted. During other BIs, group address frames are not transmitted. One example of a specific periodic BI can be a DTIM BI according to another embodiment of the invention. BI schedule 200 shows an example BI schedule consisting of normal beacon (NB) intervals 210 , 220 , 230 , and a DTIM BI 240 . Here, the group SP 241 is allocated in DTIM BI 240 . The group address frames are transmitted in the group SP 241 . The group address frames are transmitted in CBP 242 which is also allocated in DTIM BI 240 . In normal beacon intervals 210 , 220 , 230 , group address frames are not transmitted.
[0032] FIG. 3 shows a BI with a SP according to yet another embodiment of the invention.
[0033] Normally, a SP in a BI is assigned exclusively to the SP's initiator and the SP's responder. Only the SP's initiator is allowed to transmit data and/or management frames, and only the SP's responder is allowed to receive such data and/or management frames if the reverse direction (RD) protocol is not supported. Therefore, bandwidth and power are wasted when the SP's initiator has nothing to transmit resulting in an idle channel in the SP.
[0034] BI 300 shows an example BI consisting of SP 310 assigned to a SP's initiator STA1 and a SP's responder STA2 according to one embodiment of the invention. During a first period 320 of SP 310 , STA1 may send data and/or management frames exclusively, and STA2 may receive such frames from STA1 exclusively. When STA1 no longer has frames to transmit during the second period 330 of SP 310 , it may be detected that the channel medium is idle for a point (coordination function) interframe space (PIFS) in the SP. According to another embodiment of the invention, the More Data bit in the frame control field of a data frame from SP initiator STA1 can be set to ‘0’ to indicate that it has no more frames to transmit. Thereafter, the SP responder STA2 is allowed to transmit data and/or management frames to SP initiator STA1 during the third period 340 of SP 310 . According to yet another embodiment of the invention, STA1 and STA2 can also choose to go to doze state if the More Data bit from SP initiator STA1 is set to ‘0’ to indicate that it has no more frames to transmit.
[0035] FIGS. 4A and 4B show a PBSS under direct peer notification according to further yet another embodiment of the invention. PBSS 400 has PCP 410 , STA1 420 , and STA2 430 .
[0036] Normally, the wakeup schedule (WS) and power saving mode of STA1 420 and STA2 430 is stored with PCP 410 . STA1 420 and STA2 430 can acquire the peer STA's WS and power saving mode through PCP 410 .
[0037] Referring to FIG. 4A , STA1 420 and STA2 430 starts peer-to-peer communication 465 . When STA2 430 changes from active mode to power saving mode or have a new wakeup schedule, STA2 430 transmits a power saving configuration to PCP 410 to be recorded. STA1 420 , upon realizing that STA2 430 is no longer in active mode by realizing that an unsuccessful transmission threshold has been reached, may transmit an information request 455 to PCP 410 asking for the WS and power saving mode of STA2 430 .
[0038] However, a STA may not always know when to acquire such wakeup and power saving schedule of its peer STAs if a STA changes from power saving mode to active mode. If STA2 430 returns to active mode, it is difficult for peer STA1 420 to decide when to re-acquire the WS and power saving mode of STA2 430 from PCP 410 .
[0039] Direct peer notification, especially when a STA only has one peer STA, makes this notification simple and reasonable. Referring to FIG. 4B , when STA2 430 changes its power save state and/or wakeup schedule, STA2 430 may notify its wakeup schedule and/or power saving mode to peer STA1 420 directly via action frame 466 . One example of such action frame may be information response frame. An information response frame is defined for the direct peer notification to indicate a new WS. A successful exchange of an information response frame between peer STA can be used to indicate a power saving mode change according to an embodiment of the invention.
[0040] An infrastructure BSS may also be adapted to use power saving modes and transmission frames of a PBSS with some modification according to another embodiment of the invention.
[0041] Section 11.2.3 of WGA-D08 discusses power management in a PBSS, but there is no power save protocol defined for a WGA infrastructure BSS. Two possible methods for implementing a power save protocol for a WGA infrastructure are using 802.11 baseline power save protocol defined for 2.4 GHz/5 GHz infrastructure BSS or using PBSS power save protocol. However, neither of these two methods is entirely appropriate. The 2.4 GHz/5 GHz infrastructure BSS does not have SP mechanism, and normally EDCA is the medium access method in all BI. Therefore, the 802.11 baseline power save protocol defined for 2.4 GHz/5 GHz infrastructure BSS is not appropriate for power save in a WGA infrastructure BSS. With the PBSS power save protocol, a PCP can be in doze state for several BIs. Thus, this violates the rules of infrastructure BSS since an AP is always awake in an infrastructure BSS in 2.4 GHZ/5 GHz band. Therefore, the unmodified PBSS power save protocol is also not appropriate for the WGA infrastructure BSS.
[0042] As such, the following describes power saving modes and transmission frames adapted for an infrastructure BSS according to one embodiment of the invention.
[0043] An infrastructure BSS necessary consists of an AP and associated non-AP STAs. The AP, similar to the PCP in a PBSS, should operate under rules different from a non-AP STA. The AP can be in doze state in SPs that are neither the SP initiator nor the responder where the SP is not a truncatable or extensible SP, since such a SP is exclusively allocated to SP's source and SP's destination. The AP will need to be awake in other periods of the BI. However, it is noted that the AP cannot sleep for several BIs under the conditions. In other words, each BI will be AP's awake BI. Since the AP should otherwise always be active, CBP power saving for the AP in an infrastructure BSS uses the same methods of CBP power saving in PBSS CBP.
[0044] A non-AP STA may be in doze state in SPs that the STA is not the SP's initiator or responder in its active BI. A non-AP STA may also be in doze state in the CBP in its active BI if it is in power saving mode. However, the non-AP STA in active mode shall be awake during all CBP according to one embodiment of the invention.
[0045] It is further noted that an infrastructure BSS can further adapt the same methods of SP power saving in a PBSS SP as discussed according to one embodiment of the invention.
[0046] A presently preferred embodiment of the present invention and many of its improvements have been described with a degree of particularity. It should be understood that this description has been made by way of example, and that the invention is defined by the scope of the following claims.
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This invention relates to switching power saving modes and rescheduling communication frames for various periods of a beacon interval (BI) defined under WGA Draft Specification 0.8 for the personal basic service set (PBSS) and infrastructure BSS to achieve further power savings and other advantages. Stations can be awake during a contention-based period (CBP) if it is in active state and can schedule frames during a service period (SP) to allow the assigned receiver to transmit to the assigned initiator. Stations in a group can schedule a group address frame to be sent during the CBP and group SP of a specific periodic BI. Stations in peer-to-peer connection may directly notify its peer stations of its power saving mode and wakeup schedule. Stations of an infrastructure basic service set (BSS) can also use the same power saving mechanism as stations of a PBSS noting a difference where each BI will be an access point's (AP's) awake BI.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority and benefits of U.S. Provisional Patent Application 61/932,465 filed 28 Jan. 2014 and priority and benefits of U.S. Provisional Patent Application 61/941,686 filed 19 Feb. 2014. U.S. Provisional Patent Application 61/932,465 and U.S. Provisional Patent Application 61/941,686 are incorporated by reference in their entireties herein.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
This invention was made with government support awarded by the National Science Foundation under grant #1234830 and #1254540/ARL#W911NF-07-2-0026/W911NF-06-2-0011 and by DTFH61-13-H-00010 from the Federal Highway Administration. The government has certain rights in the invention.
BACKGROUND OF THE INVENTION
Field
The present disclosure relates to the deposition of nanoparticles on substrates, and, more particularly, to the deposition of nanoparticles on electrically non-conductive substrates including the formation of bonds between the nanoparticles and substrates.
Background
There has been broad scientific and technical interest in producing nanostructured composite material systems that exploit the unique properties of nanoparticles in engineering applications. The selective and intelligent integration of nanoparticles by hybridizing with various substrates enables the ability to form local multi-scale architectures for the tailoring of both mechanical and physical properties such as mechanical strength, electrical conductivity, or thermal conductivity of the nanoparticle-substrate combination.
For example, the direct hybridization where nanoparticles fully penetrate the fiber bundles of a textile, the textile forming the substrate, may be utilized as conductors for integrating sensors into the textile.
Advanced fiber-reinforced composites, such as carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) composites may offer improved in-plane tensile properties for their equivalent weight in comparison with traditional metallic materials. However, Advanced fiber-reinforced composites may exhibit poor through-thickness strength and toughness properties. Previous efforts to improve the through-thickness properties of Advanced fiber-reinforced composites, for example, have examined the addition of nanoparticles such as carbon nanotubes to a substrate comprising carbon fibers. Carbon nanotubes offer high strength and stiffness on a sub-micron scale and, therefore are potential candidates to be used to modify the interstitial regions between the carbon fibers where the polymer matrix dominates the composite strength and toughness properties.
Chemical vapor deposition processes have been used for incorporating carbon nanotubes into CFRP composites by growing CNTs directly upon the reinforcing fiber using chemical vapor deposition prior to resin infusion. The chemical vapor deposition process enables carbon nanotubes to be grown at high coverage, leading to high-effective volume fraction of the carbon nanotubes in the matrix.
Chemical vapor deposition processes may cause a reduction in the strength of the carbon fibers as well as of various non-conductive fibers, and, therefore, compromise the tensile properties. For example, chemical vapor deposition may remove sizing(s) disposed about the surface of the fibers that prevent stress corrosion cracking of the fibers or that confer ultra violet light (UV light) protection to the fibers. Removal of the sizing(s) may accordingly degrade the mechanical and physical properties of the fibers, for example, due to increased stress corrosion cracking or degradation by UV light. While the chemical vapor deposition process may be scalable, the high temperatures that may be employed for chemical vapor deposition, for example, between 600° C. and 1,000° C., makes the chemical vapor deposition process energy intensive. The chemical vapor deposition process may also be less amenable to the control of carbon nanotubes purity and manipulation of surface chemistry and adhesion of the carbon nanotubes to the surface of the substrate. Furthermore, the high temperatures of the chemical vapor deposition process may make this process inapplicable to various electrically non-conductive substrates.
Dispersion/infusion approaches have been used for incorporating carbon nanotubes into CFRP composites by inclusion of the CNT within the polymer matrix. CNT volume fraction may be limited to be generally less than 1% because processing high carbon nanotubes volumes in the polymer may be difficult due to factors such as viscosity increases, fabric filtering effects, and adequate dispersion.
Accordingly, there is a need for improved processes as well as related apparatus and compositions of matter that incorporate nanoparticles with various substrates including electrically non-conductive substrates.
BRIEF SUMMARY OF THE INVENTION
These and other needs and disadvantages may be overcome by the processes and related apparatus and compositions of matter disclosed herein. Additional improvements and advantages may be recognized by those of ordinary skill in the art upon study of the present disclosure.
In various aspects, the processes disclosed herein may include the steps of inducing an electric field about a non-conductive substrate, and depositing functionalized nanoparticles upon the non-conductive substrate by contacting a nanoparticle dispersion with the non-conductive substrate, the nanoparticle dispersion comprising functionalized nanoparticles having an electrical charge, the electric field drawing the functionalized nanoparticles to the non-conductive substrate.
In various aspects, the related composition of matter disclosed herein comprise functionalized nanoparticles bonded to a surface of a non-conductive fiber, the surface of the non-conductive fiber comprising a sizing adhered to the surface of the non-conductive fiber.
This summary is presented to provide a basic understanding of some aspects of the processes and related apparatus and compositions of matter disclosed herein as a prelude to the detailed description that follows below. Accordingly, this summary is not intended to identify key elements of the processes and related apparatus and compositions of matter disclosed herein or to delineate the scope thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates by process flow chart an exemplary electrophoretic deposition (EPD) process for the deposition of functionalized nanoparticles upon non-conductive fibers;
FIG. 2 illustrates by process flow chart an exemplary process for forming an exemplary nanoparticle dispersion for use in the exemplary EPD process of FIG. 1 ;
FIG. 3 illustrates by schematic diagram an exemplary apparatus for implementing at least portions of the exemplary process for forming an exemplary nanoparticle dispersion of FIG. 2 ;
FIG. 4A illustrates by perspective view an exemplary electrophoresis apparatus for performing the exemplary electrophoretic deposition (EPD) process of FIG. 1 ;
FIG. 4B illustrates by side view portions of the exemplary electrophoresis apparatus of FIG. 4A ;
FIG. 4C illustrates by perspective exploded view portions of the exemplary electrophoresis apparatus of FIG. 4A ;
FIG. 4D illustrates by perspective exploded view portions of another exemplary implementation of an electrophoresis apparatus;
FIG. 4E illustrates by perspective view yet another exemplary implementation of an electrophoresis apparatus;
FIG. 4F illustrates by Cartesian plot an exemplary waveform having a net zero integral as may be generated in the exemplary implementation of an electrophoresis apparatus of FIG. 4E ;
FIG. 5A illustrates by Cartesian plot exemplary results of exemplary Example 2;
FIG. 5B illustrates by Cartesian plot more exemplary results of exemplary Example 2;
FIG. 6A constitutes an SEM image of glass fiber coated with functionalized MWCNTs fabricated in exemplary Example 2;
FIG. 6B constitutes another SEM image of glass fiber coated with functionalized MWCNTs fabricated in exemplary Example 2;
FIG. 6C constitutes another SEM image of glass fiber coated with functionalized MWCNTs fabricated in exemplary Example 2;
FIG. 6D constitutes yet another SEM image of glass fiber coated with functionalized MWCNTs fabricated in exemplary Example 2;
FIG. 7A constitutes an SEM image of cross-sections of glass fibers coated with functionalized MWCNTs and then infused with resin as fabricated in exemplary Example 2;
FIG. 7B constitutes another SEM image of cross-sections of glass fibers coated with functionalized MWCNTs and then infused with resin as fabricated in exemplary Example 2;
FIG. 7C constitutes another SEM image of cross-sections of glass fibers coated with functionalized MWCNTs and then infused with resin as fabricated in exemplary Example 2;
FIG. 7D constitutes another SEM image of cross-sections of glass fibers coated with functionalized MWCNTs and then infused with resin as fabricated in exemplary Example 2;
FIG. 8A constitutes SEM images of the surfaces of glass fibers coated with functionalized MWCNTs as fabricated in exemplary Example 2 and showing porosity;
FIG. 8B constitutes SEM images of the surfaces of glass fibers coated with functionalized MWCNTs as fabricated in exemplary Example 2 and showing spalling;
FIG. 9A constitutes an optical micrograph of MWCNTs deposited upon glass fibers as fabricated in exemplary Example 4;
FIG. 9B illustrates schematically an exemplary distribution of MWCNTs deposited upon glass fibers as fabricated in exemplary Example 4;
FIG. 10A constitutes an optical micrograph of xGnP deposited upon glass fibers as fabricated in exemplary Example 4;
FIG. 10B illustrates schematically an exemplary distribution of xGnP deposited upon glass fibers as fabricated in exemplary Example 4;
FIG. 11 illustrates by exploded perspective view various exemplary apparatus employed in conducting exemplary screen printing process of FIG. 12A ;
FIG. 12A illustrates by process flow chart an exemplary screen printing process;
FIG. 12B illustrates by process flow chart details of an exemplary step of the exemplary screen printing process of FIG. 12A ;
FIG. 13 constitutes a photograph showing an exemplary pattern comprising nanoparticles printed onto an electrically non-conductive woven glass fabric; and,
FIG. 14 illustrates by perspective view an exemplary application of nanoparticle printer ink onto a non-conductive substrate by an inkjet printer.
The Figures are exemplary only, and the implementations illustrated therein are selected to facilitate explanation. The number, position, relationship, and dimensions of the elements shown in the Figures to form the various implementations described herein, as well as dimensions and dimensional proportions to conform to specific force, weight, strength, flow and similar requirements are explained herein or are understandable to a person of ordinary skill in the art upon study of this disclosure. Where used in the various Figures, the same numerals designate the same or similar elements. Furthermore, when the terms “top,” “bottom,” “right,” “left,” “forward,” “rear,” “first,” “second,” “inside,” “outside,” and similar terms are used, the terms should be understood in reference to the orientation of the implementations shown in the drawings and are utilized to facilitate description thereof. Use herein of relative terms such as generally, about, approximately, essentially, may be indicative of engineering, manufacturing, or scientific tolerances such as ±0.1%, ±1%, ±2.5%, ±5%, or other such tolerances, as would be recognized by those of ordinary skill in the art upon study of this disclosure.
DETAILED DESCRIPTION OF THE INVENTION
In various aspects, processes for the deposition of nanoparticles upon electrically non-conductive substrates and related apparatus and compositions of matter are disclosed herein. The processes for the deposition of nanoparticles upon electrically non-conductive substrate include the steps of forming a nanoparticle dispersion comprising functionalized nanoparticles dispersed in solvent with the functionalized nanoparticles having a charge, generating an electric field about the non-conductive substrate, and attracting the functionalized nanoparticles to the substrate using the electric field to deposit the functionalized nanoparticles upon the substrate.
The non-conductive substrate may be, for example, a non-conductive fiber, fabric formed of non-conductive fiber(s) including micron-sized non-conductive fibers, fabric, cloth, textile, powder including other discretized materials, in various aspects. The non-conductive substrate may be, for example, a non-woven, woven, knitted, or braided textile assembly of the non-conductive fiber(s). Non-conductive substrate, in various aspects, includes non-conductive fibers and non-conductive fibrous-like structures including their various forms: fiber bundles, fibers and bundles formed in 2-D or 3-D arrangements using textile techniques (such as braiding, weaving, knitting, stitching, etc.), non-woven fabric, and fiber-like structures such as open cell foams. Fibers can be continuous or discontinuous or a combination thereof.
The non-conductive substrate is porous, and a fluid may pass through the non-conductive substrate, in various aspects. The non-conductive substrate, in various aspects, is electrically non-conductive (i.e. an electrical insulator). The non-conductive substrate may be composed of, for example, glass, aromatic polyamide (aramid), or polyethylene terephthalate (polyester), other polymers, or other generally electrically non-conductive materials.
The solvent may be, for example, water, alcohol, or other suitable solvent. The charge of the functionalized nanoparticle may be either positive or negative.
Nanoparticle, as used herein, includes, for example, carbon nanotubes, graphene, expanded graphite nanoparticle (xGnP), graphite, carbon black, copper, silver, other metals, and other materials, as would be readily recognized by those of ordinary skill in the art upon study of this disclosure. A nanoparticle may behave as a unit with respect to transport and with respect to various physical properties. A nanoparticle may be sized, for example, in the range of from about 1×10 −9 m to about 1×10 −7 m. The nanoparticles are functionalized, in various aspects.
The functionalized nanoparticles may be formed, for example, by bonding polyethyleneimine (PEI) to oxidized carbon atoms upon surfaces of nanoparticles comprised of carbon, with the oxidized carbon atoms formed by ozonolysis of the nanoparticles. The nanoparticles may be deposited upon the substrate in various patterns, and the patterns may, for example, form electrical circuits for applications such as flexible electronics, solar cells, sensors, strain gauges, or electroluminescent displays. The nanoparticles may be bonded to the substrate by a covalent bond, and the functional group that functionalizes the nanoparticles may be selected to bond to the substrate in order to bond the nanoparticles to the substrate.
The electrophoretic deposition, screen-printing, and inkjet printing processes disclosed herein may be carried out generally at ambient (room) temperature and may be generally energy efficient, in contrast to vapor deposition processes. In various aspects, the temperature at which the electrophoretic deposition, screen-printing, and inkjet printing processes disclosed herein are carried out may range from about 5° C. to about 50° C. The electrophoretic deposition, screen-printing, or inkjet printing processes disclosed herein may be industrially scalable.
Because the electrophoretic deposition, screen printing, and inkjet printing processes may be carried out generally at ambient temperatures, the electrophoretic deposition, screen printing, and inkjet printing processes may not remove sizing(s), if any, adhering to the surface of the electrically non-conductive substrate. For example, when the substrate comprises glass fibers, sizing(s) adhering to the surface of the glass fibers may comprise silanes such as γ-glycidoxypropyltrimethoxy silane (GPS) or other silicon based compounds that adhere to glass. Sizing(s) may comprise various surfactants that, for example, control wetting of the substrate, in various implementations. The sizing(s) may increase the tensile strength of non-conductive fibers that comprise the non-conductive substrate, for example, by preventing stress corrosion cracking of the non-conductive fibers. The sizing(s) may protect non-conductive fibers that comprise the non-conductive substrate from degradation by UV light when the non-conductive fibers comprise, for example, aromatic polyamide, cotton, wool, or polyethylene terephthalate. Sizing may include various dyes. Sizing may include other material(s) and may convey various beneficial properties to the various non-conductive substrates, as would be readily recognized by those of ordinary skill in the art upon study of this disclosure. The sizing(s) may be disposed between the surface of non-conductive fibers forming a non-conductive substrate and functionalized nanoparticles deposited upon the non-conductive fiber to retain, for example, the resistance to stress corrosion cracking of the non-conductive fiber imparted to the non-conductive fiber by the sizing agent, in various aspects.
In various aspects, functionalized nanoparticles in a nanoparticle dispersion are deposited upon the non-conductive substrate. The process of forming the functionalized nanoparticle dispersion may include ozonolysis in alternating combination with high-energy circulative sonication of a solution of nanoparticles to oxidize the nanoparticles and to break up agglomerations of nanoparticles, respectively. Following the steps of ozonolysis in combination with sonication, the process may include the step functionalizing the nanoparticles by attaching functional groups to the surface of the nanoparticles in order to form a functionalized nanoparticle dispersion that is stable. In various aspects, the nanoparticle dispersion is water-based, although other solvents may be used in lieu of water or in combination with water. The addition of functional groups onto the surface of the nanoparticles may be crucial for forming the stable functionalized nanoparticle dispersion by altering the zeta potential of the nanoparticles. The addition of functional groups onto the surface of the nanoparticles may enhance bonding between the nanoparticles and non-conductive fibers to which the nanoparticles are to be bonded, in various aspects. The step of adding functional groups onto the surface of the nanoparticles may include adding a polyelectrolyte to the ozonated and sonicated solution of nanoparticles and then further sonicating the polyelectrolyte—nanoparticle mixture thereby bonding the polyelectrolyte as the functional group to the surface of the nanoparticle.
In various aspects, a variety of additives may be combined with the functionalized nanoparticle dispersion following formation of the functionalized nanoparticle dispersion, for example, to modify the surface tension in order to enable wetting of a surface of the non-conductive substrate by the functionalized nanoparticle dispersion. Various additives may be combined with the functionalized nanoparticle dispersion to alter the viscosity of the functionalized nanoparticle dispersion.
Although the Examples included in this disclosure are generally for carbon nanotubes and graphene nanoplatelets, the techniques for integration may be amenable to a wide range of nanostructures. Similarly, although the Examples herein are generally for glass fiber, the electrophoretic deposition, screen printing, and inkjet printing processes have been successfully applied to aromatic polyamide (aramid), polyethylene terephthalate (polyester), cotton, wool, and to various other non-conductive fibers.
FIG. 1 illustrates an exemplary electrophoretic deposition (EPD) process 100 for the deposition of functionalized nanoparticles upon a non-conductive substrate. EPD process 100 is entered at step 101 . At step 103 , a nanoparticle dispersion, such as nanoparticle dispersion 128 , is formed. The nanoparticle dispersion 128 may be formed by process 200 , which is illustrated in FIG. 2 . The nanoparticle dispersion 128 comprises functionalized nanoparticles dispersed in a solvent such as water.
At step 105 , the functionalized nanoparticles are deposited upon a non-conductive substrate. The non-conductive substrate is biased against an electrode, and positioned between the electrode and the opposing electrode. The nanoparticle dispersion is interposed between the electrode and an opposing electrode, and the nanoparticle dispersion is in contact with the non-conductive substrate. A voltage potential is applied between the electrode and the opposing electrode to generate an electrical field about the non-conductive substrate to attract the charged functionalized nanoparticles toward the non-conductive substrate in order to deposit the functionalized nanoparticles upon the non-conductive substrate. The applied field may be constant or time varying. In other implementations, the electrical field may be generated by imparting a static electric charge to the non-conductive substrate, and the nanoparticle dispersion may be introduced to the non-conductive substrate as an aerosol with the functionalized nanoparticles attracted by the static electric charge of the non-conductive substrate. In still other implementations, the nanoparticle dispersion may be dispersed as an aerosol between the electrodes instead of as a liquid.
At step 111 , the non-conductive substrate is withdrawn from contact with the nanoparticle dispersion and the non-conductive substrate is allowed to dry.
At step 117 , the non-conductive substrate is infused with a polymer when manufacturing a hybrid composite. Exemplary EPD process 100 terminates at step 121
FIG. 2 illustrates an exemplary process 200 for forming exemplary nanoparticle dispersion 128 . Step 103 of EPD process 100 , which is illustrated in FIG. 1 , may be implemented according to process 200 , which is illustrated in FIG. 2 . Process flows in FIG. 2 are indicated by arrows and material inputs and material outputs are indicated by the double arrows.
As illustrated in FIG. 2 , process 200 is entered at step 203 , and process 200 advances from step 203 to step 210 . At step 210 , nanoparticles 106 are combined with water 104 as solvent to form a nanoparticle-water mixture. Other solvents may be used in other implementations. The water may be ultra-pure, deionized, and so forth. The nanoparticle-water mixture formed at step 210 is then ozonated by the addition of O 3 to the water-nanoparticle mixture at step 215 . Ozonation may create various oxidized sites on the surface of the nanoparticle to which the functionalizing material 108 may then bond to functionalize the nanoparticle. The functional group, in various implementations, includes the oxidized carbon bonded to the functionalizing material 108 .
The nanoparticle-water mixture is sonicated at step 217 with the ozonation and the sonication occurring alternately as the nanoparticle-water mixture flows between an ozonation reservoir 425 and a sonicator cell 420 (see FIG. 3 ). As illustrated in FIG. 2 , step 215 and step 217 are repeated in alternation with one another until the ozonation of step 215 in combination with the sonication of step 217 is sufficient to oxidize surfaces of the nanoparticles and to separate the nanoparticles, respectively.
After sufficient ozonation and sonication at steps 215 , 217 , process 200 then advances from steps 215 , 217 to step 220 . At step 220 , the functionalizing material 108 is added to the nanoparticle-water mixture to functionalize the nanoparticles by bonding to the nanoparticles. The water-nanoparticle mixture with the functionalizing material 108 is then sonicated at step 225 to facilitate functionalizing the nanoparticles by the functionalizing material 108 . Following sonication, the functionalized nanoparticle dispersion 128 is output from step 225 . Process 200 terminates at step 231 .
The functionalizing material 108 may comprise a polyelectrolyte such as polyethyleneimine (PEI). Various molecular weights of PEI may be used, in various implementations. Some implementations may omit functionalizing material 108 and steps 220 , 225 . In such implementations, the functional groups are the oxidized sites such as oxidized carbon atoms on the surface of the nanoparticles. Nanoparticles comprised of carbon have a negative charge following ozonation at step 215 .
Example 1
The nanoparticles, in exemplary Example 1, comprise multi-walled carbon nanotubes (MWCNT) (CM-95, Hanwha Nanotech, Korea) functionalized according to process 200 to produce a functionalized nanoparticle dispersion, such as functionalized nanoparticle dispersion 128 (see FIG. 2 ). Steps 210 , 215 , 220 , 225 of process 200 , in Example 1, were implemented, at least in part, using apparatus 400 , which is illustrated in FIG. 3 . Exemplary material flows through apparatus 400 are indicated by the arrows in FIG. 3 .
As illustrated in FIG. 3 , oxygen with a flow rate of 500 mL/min flows from reservoir 440 through moisture trap 435 , and, then the oxygen flows from moisture trap 435 to ozone generator 430 (1000BT-12 from Taoture International). Moisture trap 435 removes water (moisture) from the oxygen prior to introduction of the oxygen into ozone generator 430 . Ozone generator 430 produces ozone from the oxygen.
Ozone from ozone generator 430 flows from ozone generator 430 into ozonation reservoir 425 where the ozone contacts the MWCNT-water mixture in order to ozonate the MWCNT-water mixer per step 215 of process 200 . Ozonation reservoir 425 , in this implementation, is maintained at 5° C. by immersion of ozonation reservoir 425 in temperature control bath 426 . Ozone concentration reached 20 mg/L after 2 h of operation as determined by iodometric titration.
As illustrated in FIG. 3 , the MWCNT-water mixture was sonicated in sonicator cell 420 per step 217 of process 200 . Sonication of the MWCNT-water mixture in sonicator cell 420 used a 12.7 mm diameter horn operating at 60 W (Sonicator 3000 from Misonix, USA). Sonicator cell 420 , in this implementation, was maintained at 5° C. by immersion in temperature control bath 421 . Water is circulated between temperature control bath 421 and temperature control bath 426 , in this implementation.
In this exemplary implementation of steps 215 , 217 of process 200 , the MWCNT-water mixture was ozonated and sonicated for 16 h. A peristaltic pump 410 (Model MU-D01 from Major Science, USA) recirculated the MWCNT-water mixture between ozonation reservoir 425 and sonicator cell 420 (800B Flocell, Qsonica), as illustrated in FIG. 2 . Accordingly, steps 215 , 217 of process 200 were applied to the MWCNT-water mixture as the MWCNT-water mixture recirculated between ozonation reservoir 425 and sonicator cell 420 in a continuous flow process, so that the MWCNT-water mixture was continuously ozonated and sonicated, respectively.
After 16 hours of sonication, the few agglomerates observed were all submicron in size. Ozonolysis oxidized carbon atoms generally on the surface of the MWCNT, and the oxidized carbons may form, for example, carboxyl groups, hydroxyl groups, or carbonyl groups. Following ozonolysis, the MWCNTs, in this implementation, are functionalized by the oxidized carbons on the surface and have a negative surface charge.
The functionalizing material 108 introduced into the now sonicated and ozonated MWCT-water mixture at step 220 of process 200 as implemented in Example 1 was polyethyleneimine (PEI) (H(NHCH 2 CH 2 ) 58 NH 2 ; Mw 25,000; Sigma-Aldrich, USA). Other molecular weights of PEI may be used in other implementations. The PEI was at equal concentration to the MWCNT, in this Example. The PEI-MWCNT-water mixture was sonicated for 4 h in the Example 1 implementation of step 225 of process 200 to functionalize the MWCNT by bonding the PEI to the MWCNT in order to form the functionalized nanoparticle dispersion, such as functionalized nanoparticle dispersion 128 . The PEI may bond to the oxidized carbons on the surface of the MWCNT, and the PEI may be bonded to the MWCNT by a covalent bond. The pH of the PEI-MWCNT-water was adjusted with glacial-acetic add (Sigma-Aldrich) to a pH around 6 during step 225 . The resultant nanoparticle dispersion was then output from apparatus 400 .
The functionalization of the MWCNTs enables a surface charge to develop, and the PEI functionalized MWCNTs have a positive surface charge. The surface charge, which may be described in terms of zeta-potential, may be dependent on the solution pH and may repulse adjacent MWCNTs to aid dispersion and mobility under applied electric fields. PEI has a high-natural pH in aqueous solution, but with addition of a mild acid, the amine groups protonate and a +50 mV zeta-potential may be established below a pH of 8, enabling cathodic deposition of the PEI-functionalized MWCNTs. The resultant functionalized nanoparticle dispersion of Example 1 has been stable for at least a year.
In electrophoretic deposition (EPD), an electric field is induced about a non-conductive substrate. Then, the functionalized nanoparticle, which has a surface charge, is accelerated in the electric field toward the non-conductive substrate for deposition on the non-conductive substrate. As illustrated in FIG. 4A , functionalized nanoparticles 461 may be deposited upon non-conductive substrate 476 that comprises fabric 480 formed of non-conductive fibers 482 by, at least in part, electrophoresis of a functionalized nanoparticle dispersion, such as functionalized nanoparticle dispersion 128 . Non-conductive substrate 476 , fabric 480 , and non-conductive fibers 482 are electrically non-conductive, in this implementation.
In the exemplary implementation of FIG. 4A , electrophoresis apparatus 450 comprises source 457 in communication with electrode 454 having negative charge (cathode) and in communication with an opposing electrode 452 having positive charge (anode). Source 457 , in the illustrated implementation, is a constant source that applies a constant voltage potential between opposing electrode 452 and electrode 454 .
Nanoparticle dispersion 128 including functionalized nanoparticles 461 , as illustrated in FIG. 4A , is disposed between electrode 454 and opposing electrode 452 . In the implementation of FIG. 4A , functionalized nanoparticles 461 have a positive surface charge as, for example, the PEI functionalized MWCNTs of Example 1. The functionalized nanoparticles 461 (positive charge), in this implementation, are repelled by the like charged opposing electrode 452 (positive charge), and the functionalized nanoparticles 461 are drawn to the oppositely charged electrode 454 (negative charge) by the electric field induced about non-conductive substrate 476 by electrodes 452 , 454 .
Non-conductive substrate 476 is biased against electrode 454 between electrode 454 and opposing electrode 452 , and non-conductive substrate 476 is in contact with nanoparticle dispersion 128 . Non-conductive substrate 476 is illustrated in FIG. 4A as partially covering electrode 454 for explanatory purposes. Electrode 454 induces a positive electric field around non-conductive substrate 476 to attract the functionalized nanoparticles 461 into contact with the non-conductive substrate 476 for deposition upon non-conductive substrate 476 . The porous nature of non-conductive substrate 476 may facilitate the induction of the electric field about non-conductive substrate 476 by electrodes 454 by allowing charge to pass through the pores of non-conductive substrate 476 . (Note that juxtaposing a non-porous non-conductive substrate between electrodes 452 , 454 may form a capacitor.)
The transport of functionalized nanoparticles, such as functionalized nanoparticles 461 , toward the electrode 454 and non-conductive substrate 476 may depend upon the mobility of the functionalized nanoparticles 461 that, in turn, may depend upon the size of the functionalized nanoparticles and the magnitude of the surface charge of the functionalized nanoparticles.
The surface charge of the functionalized nanoparticles may be negative in other implementations, for example, MWCNT following ozonolysis. For example, in implementations with negatively charged functionalized nanoparticles, the functionalized nanoparticles are drawn to the positively charged anode 452 , and the non-conductive substrate, such as non-conductive substrate 476 , is disposed about opposing electrode 454 which then induces a positive electric field about non-conductive substrate 476 .
As illustrated in FIG. 4B , mask 486 overlays portions of the non-conductive substrate 476 in biased engagement with non-conductive substrate 476 during deposition to shield the portions of non-conductive substrate 476 engaged with mask 486 from deposition of functionalized nanoparticles 461 . The mask 486 physically blocks the deposition of functionalized nanoparticles 461 onto those portions of non-conductive substrate 476 overlain by mask 486 .
Mask 486 may be variously shaped, for example, as illustrated in FIG. 4C , to create a patterned deposited morphology of the functionalized nanoparticles 461 upon non-conductive substrate 476 . Mask 486 may define a non-deposited region 488 on non-conductive substrate 476 that conforms to the shape of the mask 486 within which the functionalized nanoparticles 461 are not deposited upon non-conductive substrate 476 . Deposited region 487 on non-conductive substrate 476 is that portion of non-conductive substrate 476 that is not covered by the mask 486 within which the functionalized nanoparticles 461 are deposited on the non-conductive substrate 476 , as illustrated in FIG. 4C . Deposited region 487 , as illustrated, has pattern 489 that may, for example, define electrically conductive pathway(s) on non-conductive substrate 476 . Mask 486 may be either conductive or non-conductive, in various implementations. If mask 486 is formed of a non-conductive material, mask 486 decreases the electric field proximate those portions of non-conductive substrate 476 overlain by mask 486 during EPD.
As illustrated in FIG. 4D , electrode 458 of electrophoresis apparatus 490 is shaped to create a patterned deposited morphology of the functionalized nanoparticles 461 upon non-conductive substrate 467 having pattern 471 . Because intimate contact between electrode 458 and non-conductive substrate 467 may be required for deposition of functionalized nanoparticles 461 upon non-conductive substrate 467 , the functionalized nanoparticles 461 may be deposited in a pattern 463 upon non-conductive substrate 467 by correspondingly patterning electrode 458 that biases against non-conductive substrate 467 during the EPD process. Note that, in this FIG. 4D implementation, non-conductive substrate 467 is formed of non-conductive fibers, such as non-conductive fibers 482 .
As illustrated in FIG. 4D , functionalized nanoparticles, such as functionalized nanoparticles 461 , are deposited upon non-conductive substrate 467 by EPD in a deposited region 463 having pattern 471 corresponding to the shape of electrode 458 . The deposited region 463 may, for example, define pattern 471 of electrically conductive pathways 473 upon non-conductive substrate 467 with a desired configuration. Non-deposited regions 459 where functionalized nanoparticles are not deposited may be formed on portions of non-conductive substrate 467 not in biased engagement with electrode 458 , as illustrated in FIG. 4D .
Various combinations of masks, such as mask 486 , and electrodes, such as electrode 454 , 458 , may be combined with one another to create various patterns and combinations of patterns, such as patterns 471 , 489 , of deposited functionalized nanoparticles upon non-conductive substrate, such as non-conductive substrate 476 , 467 . The patterns of functionalized nanoparticles so formed may be hierarchically structured, in various implementations. The nanoscale conductive network can be utilized, itself, as a sensor where the piezoresistive properties of the network can be exploited to sense deformation, temperature and other external stimuli. The hybridization enables the future integration of adaptive, sensory, active, or energy storage capabilities of nanostructures within non-conductive substrate such as textile materials. Other applications may include EMI shielding and heating of the non-conductive substrate through resistive energy dissipation.
Process parameters that may effect the EPD process may include concentration of functionalized nanoparticles in the nanoparticle dispersion, surface charge of the functionalized nanoparticles, spacing between the electrodes, applied field strength, and deposition time. While electro-kinetic factors lead to the deposition of functionalized nanoparticles on non-conductive fibers and film formation on the non-conductive fibers, Brownian diffusion randomizes the particle distribution in solution. Brownian diffusion redistributes the functionalized nanoparticles into inter-fiber regions at longer deposition times.
A constant source, such as source 457 , may cause electrolysis of water and the formation of hydrogen and oxygen bubbles that result in micro-scale porosity and spalling of the deposited functionalized nanoparticles. Furthermore, functionalized nanoparticles may precipitate from solution when a constant source is used due to the high pH gradients that develop near the electrode, such as electrode 454 , and cause solution instability.
Accordingly, in electrophoresis apparatus 510 , voltage source 507 is configured as a time varying source, as illustrated in FIG. 4E . In the exemplary implementation of FIG. 4E , electrophoresis apparatus 510 comprises source 507 in communication with electrodes 501 , 509 . As illustrated, nanoparticle dispersion 128 with functionalized nanoparticles 161 lies between electrodes 501 , 509 .
In the implementation of FIG. 4E , voltage source 507 is configured to generate a waveform having a net zero integral. For example, the exemplary waveform generated by source 507 is that of a simple triangular asymmetric wave where the integral over a single period is zero as illustrated in FIG. 4F . Other waveforms having a net zero integral may be used in other implementations. The net zero integral suppresses the electrolysis of water, thereby eliminating the spalling and micro-porosity that may occur with a DC source. Furthermore, the suppression of electrolysis may reduces or eliminates the pH gradient and may enable deeper and more efficient penetration of the functionalized nanoparticles into fiber bundles of fibers, such as fibers 482 . In addition, the alternating mobility of the functionalized nanoparticles may further enhance penetration of the functionalized nanoparticles into fiber bundles.
At high electric fields the velocity of the functionalized nanoparticle 461 being deposited is a non-linear function of the electric field expressed by:
V eph =μ 1 E+μ 2 E 3 (1)
where V eph is the velocity of the functionalized nanoparticle 461 , E is the voltage potential, and μ 1 and μ 2 are the linear electrophoretic mobility and non-linear electrophoretic mobility, respectively. Because of the non-linearity of Eq. 1, the functionalized nanoparticle 461 moves a greater distance during the high amplitude segment of the waveform of FIG. 4F than during the low amplitude segment of the waveform of FIG. 4F . Accordingly, the positively charged functionalized nanoparticle 461 will be drawn to the one of electrodes 501 , 509 that is negatively charged during the high amplitude segment of the wave form of FIG. 4F in preference to the other of electrodes 501 , 509 that is negatively charged during the low amplitude segment of the waveform of FIG. 4F . Other waveforms having a net zero or net non-zero integral may be used in other implementations.
Example 2
Functionalized nanoparticles in various nanoparticle dispersions were deposited by EPD process under differing conditions upon a non-conductive fabric formed of E glass fibers (non-conductive) and upon a conductive fabric formed of carbon fibers (conductive) in Example 2 for purposes of comparison. The functionalized nanoparticles were MWCNT functionalized with PEI as in Example 1.
Sizing, such as GPS, if any, were not removed from the glass fiber during deposition of functionalized nanoparticles upon the glass fiber by the EPD process. The EPD process, in this Example, was carried out generally at ambient (room) temperature. Because EPD is carried out generally at ambient temperature, the EPD process does not remove sizing, if any, from the surface of other non-conductive fibers, in other implementations.
The glass fiber deposition mass for the nanoparticle dispersion at field strengths between 12.5 and 64 V/cm is shown in the FIG. 5A . In the initial linear deposition stage it was possible to estimate the deposition rate as a function of field strength, which is shown in FIG. 5B . The deposition rate for glass fibers is compared to that measured for carbon fibers in FIG. 5B . As can be seen from FIG. 5B , the deposition rate upon glass fibers at the same field strength is about the same as the deposition rate upon carbon fibers where the concentration of the nanoparticle dispersion for carbon fibers was only half the concentration of the nanoparticle dispersion for glass fibers. On the basis of the linear dependence of deposition rate with dispersion concentration, the deposition rate on glass is around half that observed on carbon fibers. The reduced rate may be expected as the film deposition process on glass fiber (non-conductive) would differ when compared to the film deposition process on carbon fiber (conductive).
FIGS. 6A-6D shows MWCNTs deposited on the E-glass fiber from the nanoparticle dispersion at 25 V/cm for 15 min. The film appears to be compact with the MWCNTs embedded in the PEI polymer. The outer surface of the fabric ( FIG. 6A, 6B ) shows a uniform film around 2 μm thick. Deeper into the fabric tow ( FIG. 6C, 6D ) the film appears as uniform and between 50 and 200 nm. Process parameters may be optimized to control the thickness.
The following mechanism of MWCNT deposition upon the fabric is hypothesized. The MWCNTs precipitate out of solution onto the electrode and onto the surface of the fabric that is biased against the electrode. The portions of the fabric onto which the MWCNTs are deposited then become incorporated into the electrode. This initiation of precipitation of the MWCNTs at the electrode and fabric in biased contact with the electrode may explain why intimate contact is required between non-conductive substrates and the electrode. As portions of the fabric become incorporated into the electrode, the precipitation of the MWCNTs occurs at the boundary between the portion of the fabric incorporated into the electrode and remaining portions of the fabric. Accordingly, precipitation of the MWCNTS progresses from the surface of the fabric that is biased against the electrode outwardly into pores in the fabric to form the film upon fibers within the pores. As the MWCNTs build up upon the fibers, the MWCNTs, which are conductive, may bridge between fibers within the pores to extend the electrode into the fabric. The build-up of MWCNTs in the pores continues progressively from the surface of the fabric biased against the electrode outwardly through the fabric until the build up of MWCNTs reaches the opposite surface of the fabric. When the build up of MWCNTs reaches the opposite surface of the fabric, the fabric is incorporated into the electrode, and MWCNTs are deposited upon the opposite surface of the electrode by attraction to the opposite surface and precipitation upon the opposite surface. Accordingly, the deposition of MWCNTs upon the opposite surface and throughout the fabric may occur by precipitation, not by sedimentation.
Continuing the hypothetical discussion of deposition of MWCNTs, the precipitation of the PEI functionalized MWCNTs or other functionalized nanoparticles may occur by de-protonation of, for example, the PEI functional group at the electrode. Electrolysis of the water may enhance de-protonation and, thus, the precipitation of the MWCNTs. Accordingly, regulation of electrolysis may control the precipitation of the MWCNTs. The porosity of the combination substrate-MWCNTs may be controlled by controlling the precipitation of MWCNTs along with selecting the size of the nanoparticles (MWCNTs). It may be advantageous to use a time varying source with a non-zero integral (bias), in some implementations, to regulate electrolysis in order to control precipitation. This concludes this particular hypothetical discussion.
It was also noted during the experiments that the MWCNTs became strongly attached to the conductive electrode. Abrasion using sandpaper was required to remove the MWCNTs from the electrode, which was made of stainless steel.
Polished cross-sections of the polymer-infused glass-fibers with MWCNTs deposited were also examined to determine porosity and MWCNT distribution throughout the laminate, as shown in FIGS. 7A-7D . The film that builds up on the outer fibers appears to be well infused ( FIG. 7A ) and there are few voids, even when observed at high magnification ( FIG. 7B ), indicating the resin diffuses through the coating and produces a good-quality, low-void laminate. Further into the interior of the fabric, the coating thickness decreases and a thin MWCNT coating is observed around individual fibers together with a network that spans between adjacent fibers ( FIGS. 7C, 7D ). The Figures show examples of microscale porosity ( FIG. 8A ) and spalling ( FIG. 8B ) of the deposited MWCNTs. The microscale porosity and spalling may be the result of the use of a constant voltage source and attendant electrolysis of water.
Functionalized nanoparticles may be deposited in various patterns onto fabrics formed of non-conductive fibers by a screen-printing process, such exemplary screen-printing process 700 (see FIG. 12A ), using screen ink, such as screen ink 640 (see Example 3 and FIG. 11 ). The screen ink may also serve as a sizing for the non-conductive substrate. Sizing on the non-conductive fibers of the non-conductive substrate are not removed by the screen-printing process, in various implementations. Additional processing constraints that may be inherent to the screen-printing may require modification of surface tension and viscosity of the nanoparticle dispersion to obtain an ink with desirable rheological properties.
As illustrated in FIG. 12A , screen-printing process 700 is initiated at step 701 . At step 707 , the screen ink is formed. At step 711 , the stencil is made. Then, at step 717 , the screen ink is applied to the non-conductive substrate using the stencil in ways as would be readily recognized by those of ordinary skill in the art upon study of this disclosure. The non-conductive substrate may have a static electric charge to attract the functionalized nanoparticles. Process 700 terminates at step 721 .
Example 3
Screen ink 640 , in this Example, was formed by, first, adding a coalescing agent (PVP K-90, Ashland Inc.) to ultra-pure water to form a mixture. Then, a polymeric ink binder (Polyox WSR N-60k, Dow) was added to the mixture. The coalescing agent ensures an even dispersion of the polymeric ink binder, which promotes adhesion of the deposition to the glass fibers of a glass fiber fabric. Non-conductive substrate 630 to which the screen ink 640 was applied, in this Example, was a fabric formed of unidirectional E-glass fibers that are electrically non-conductive, so that the substrate was electrically non-conductive. The binder is required to increase the screen ink's surface energy, because the surface energy of the ultrapure water (72 dynes/cm 2 ) exceeds the surface energy of the glass fibers (46 dynes/cm 2 ) causing poor wetting of the glass fibers. The viscosity of the mixture may then be adjusted with hydroxyethyl cellulose water-soluble polymer (Cellosize QP 52000, Dow) to thicken and impart a thixotropic behavior to the mixture. A thixotropic fluid is a form of pseudo-plasticity where the apparent viscosity of the thixotropic fluid decreases over time or ‘thins out’ during application of a constant shear rate to the thixotropic fluid. Shear thinning may be an essential property for printing clear patterns with consistent thicknesses and substrate penetration. All aforementioned rheological additives—coalescing agent, polymeric ink binder, hydroxyethyl cellulose water-soluble polymer—are added to the mixture at 1 weight % of the ultra-pure water in the order of presentation to form the precursor solution.
Nanoparticles are then added to the precursor solution to form the screen ink. The nanoparticles comprise chemical vapor deposition-grown multi-walled carbon nanotubes (MWCNT) from Hanwha Nanotech (CM-95, >95% graphitic carbon, Korea) and exfoliated graphite nanoplatelets (xGnP). The nanoparticles are processed to reduce the agglomerated nanomaterials to the desired morphology. First, the MWCNT are added to the precursor solution and the precursor solution containing the MWCNT is then processed by calendering. Calendering untangles the several micron-long MWCNT that is agglomerated into intertwined bundles while maintaining the desirable aspect ratio, thus enabling electrical percolation at lower concentrations. There exists a non-linear relationship between the extent of carbon nanotube processing and electrical resistivity where smaller gap settings in the calendering mill create local maximum and minimum resistivity values indicating a transition from agglomerated particulate versus disentangled carbon nanotube dispersion.
Second, after calendering the MWCNTs, the as-received powdered xGnP nanomaterial is added to the precursor solution and then processed by a shear mixing approach using a three-roll calendering mill. The larger size of the xGnP in comparison to the MWCNT requires processing in the calendaring mill at larger gap settings than the WMCNT to achieve an electrically conductive solution but requires less processing than carbon nanotubes, which require processing at finer gap settings. Shearing of the xGnP turbostatic carbon planes into the idealized few layer graphene increases the effectiveness of its nanocomposites.
The precursor solution with the added MWCNT and xGnP nanoparticles and following the calendaring of both the MWCNT and xGnP nanoparticles constitutes the screen ink 640 (see FIG. 11 ). The MWCNT and xGnP nanoparticles, for example, provide the necessary electrical conductivity to form sensor networks in the non-conductive substrate for damage sensing or strain sensing.
Example 4
Screen ink 640 formed according to Example 3 including the MWCNT and xGnP nanoparticles dispersed therein was deposited onto unidirectional E-glass substrate 630 in the desired pattern through use of an adapted screen-printing process, as per step 717 of process 700 .
The stencil was made, per step 711 of process 700 , according to process 750 illustrated in FIG. 12B . Process 750 is initiated at step 751 , and mesh fabric 611 is stretched at step 757 . In this implementation of process 750 , a 120-count mesh fabric 611 was stretched by application of a force of 18 N to 22 N, as illustrated in FIG. 11 . The mesh fabric 611 , per step 761 of process 750 , was coated with a UV-sensitive emulsion 613 (illustrated in FIG. 11 as partially covering mesh fabric 611 for explanatory purposes). Then, per step 767 of process 750 , a transparency sheet 617 with a high opacity image 619 was used to shield regions of the mesh fabric 611 to prevent cure of the shielded regions thereby forming uncured regions 625 that conform to the high opacity image 619 (also see FIG. 11 ). Other regions of the mesh fabric 611 were left exposed to allow curing of the exposed regions thereby forming cured regions 623 , as illustrated in FIG. 11 . A UV light was applied to the mesh fabric causing curing of the exposed regions to form the cured regions 623 while the shielded regions remained uncured to form uncured regions 625 , per step 771 of process 750 . The uncured regions 625 conform to nanoparticle pathways 635 to be formed in the substrate 630 , as illustrated in FIG. 11 .
Following curing by application of the UV light, the mesh fabric 611 was rinsed with water to expose the mesh of the uncured regions 625 and to remove uncured UV sensitive emulsion 613 , as per step 775 of process 750 . The mesh of the mesh fabric 611 was blocked by the cured UV-sensitive emulsion 613 in cured regions 623 . The mesh fabric 611 with uncured regions 625 having exposed mesh and cured regions 623 having a blocked mesh forms stencil 628 .
In applying the screen ink 640 to substrate 630 as per step 717 of process 700 , the stencil 628 was set above the substrate 630 in the 0° fiber direction. The screen ink 640 is then directed through the mesh of the un-cured regions 625 by hand using a blade at a consistent speed and pressure by in both forward and backwards directions twice to ensure a high quality print. After screen printing according to process 700 , the substrate 630 was heated at 60° C. for four hours in a vented convention oven to expel the aqueous base of the screen ink leaving the nanoparticle adhered to the substrate 640 . The nanoparticles form pathways 635 upon the substrate 630 in conformance to the uncured regions 625 with exposed mesh of the stencil 628 . The substrate 630 may then be infused with resin. Silver paint may be applied to the pathways at selected locations to provide electrical contact with the pathways.
Observation of the optical micrographs in FIG. 9A and FIG. 10A may elucidate the difference in damage sensing versus strain sensing between the MWCNT nanoparticles 661 and the xGnP nanoparticles 663 . As indicated by FIG. 9A , the MWCNT nanoparticles 661 appear to be dispersed across the fiber lamina and penetrates within the fiber bundles to form an electrically conductive, non-invasive in situ network throughout the substrate 630 . The MWCNT nanoparticles 661 may preferentially form conductive pathways along the fiber direction.
The xGnP nanoparticles 663 , as indicated in FIG. 10A , do not penetrate the fiber bundles, in this Example, so that the xGnP nanoparticles 663 create an electrically conductive network adhered atop the substrate 630 with minimal penetration and with reduced sensitivity compared to the carbon nanotube sensor.
Illustrations of the microstructure are included to aid in the visualization of the deposited MWCNT nanoparticle 661 sensor network and xGnP nanoparticle 663 sensor network in FIG. 9 B and FIG. 10B . Lower xGnP nanoparticle sense baseline resistance values may be the result of a higher concentration of conductive nanomaterial being confined to a limited space on top of the substrate 630 .
Hierarchically structured patterns of nanoparticles may be deposited onto fabrics formed of non-conductive fibers by an ink jet printing process using an ink jet printer with nanoparticle printer ink. While the electrophoretic and screen hybridization approaches may require specific geometry-s or screens, respectively, to form patterns, inkjet printing may be used to form patterns of nanoparticles on a variety of substrates including non-conductive substrates form of non-conductive fibers. The nanoparticles in the patterns formed by inkjet printing may include carbon nanotube, graphene, or combinations of carbon nanotube and graphene. The patterns may form electrical circuits for applications such as flexible electronics, solar cells, sensors, strain gauges, and electroluminescent displays.
A nanoparticle dispersion with carbon nanotubes as the nanoparticle may be specifically formulated to have low viscosity. After oxidation of the nanoparticles, the nanoparticles may be functionalized by the attachment of chemical groups to the surface of the nanoparticle to improve the adhesion between the nanoparticle and the fiber surface of the non-conductive fibers forming the fabric upon which the nanoparticles are deposited. After a stable nanoparticle dispersion is obtained, a variety of additives may be added to the nanoparticle dispersion to enable wetting of the fabric surface or to modify the viscosity of the nanoparticle dispersion. The resultant nanoparticle dispersion may form the nanoparticle printer ink. The nanoparticle printer ink may be applied to the fabric, which is the substrate in this implementation, by use of the inkjet printer.
Use of inkjet printing to apply the nanoparticle printer ink to fabric, which is the non-conductive substrate in this implementation, may enables higher resolution patterning of the patterns of nanoparticles in comparison with either EPD or the screen printing process. Inkjet printing of patterns with nanoparticle printer ink may offer more flexibility in the design of the electrically conductive networks than either EPD or the screen printing processes. In various implementations, inkjet printing of patterns of nanoparticle printer ink may be industrially scalable.
As illustrated in FIG. 14 , the nanoparticle printer ink 811 may form an aerosol as the nanoparticle printer ink 811 is dispensed from the inkjet printer 805 onto the non-conductive substrate 820 , and the non-conductive substrate 820 may have a static electric charge to attract the functionalized nanoparticles in the aerosolized nanoparticle printer ink 811 to the non-conductive substrate 820 . Nanoparticle printer ink 811 forms pathway 825 on non-conductive substrate 820 , as illustrated in FIG. 14 . Aerosol may include a single droplet or single particle in gas including air.
FIG. 13 illustrates a pattern comprising nanoparticles printed onto an electrically non-conductive woven glass fabric in a rectangular pattern by an inkjet printer. The pattern appears as the darker lines in the photograph. The functionalized nanoparticle dispersion 128 of Example 1 was used at the nanoparticle printer ink in the implementation of FIG. 13 . Key processing parameters may include the droplet size, solution concentration, and motion of the inkjet head. Different processing conditions result in varying nanotube morphologies on the fabric. Control of the process enables tailoring of the percolating structure to achieve desired electrical properties.
In various implementations, the processes disclosed herein may include the steps of forming screen ink comprising a nanoparticle dispersion, making a stencil, the stencil allowing the selective passage of the screen ink through the stencil to form pathways in the substrate, and forming pathways of nanoparticles in the fabric by applying the screen ink to the fabric with the stencil interposed between the screen ink and the fabric.
In various implementations, the processes disclosed herein may include the steps of formulating nanoparticle printer ink comprising a nanoparticle dispersion, and depositing hierarchically structured patterns of functionalized nanoparticles upon a fabric by inkjet printing of the nanoparticle printer ink onto the fabric using an inkjet printer.
In various implementations, the processes disclosed herein may form related composition of matter, comprising functionalized nanoparticles bonded to a surface of a non-conductive fiber, the surface of the non-conductive fiber comprising a sizing adhered to the surface of the non-conductive fiber. The composition of matter may further comprising an electric field disposed about the non-conductive fiber. In the composition of matter, the functionalized nanoparticles bonded to the surface of the non-conductive fiber forming a uniform coating upon the non-conductive fiber. The functionalized nanoparticles in the various compositions of matter may include nanoparticles functionalized with polyethyleneimine (PEI) bonded to oxidized carbon atoms on surfaces of the nanoparticles, the nanoparticles selected from a group consisting essentially of carbon nanotubes and graphene. The functionalized nanoparticles in the various compositions of matter may include nanoparticles functionalized with oxidized carbon atoms on surfaces of the nanoparticles, the nanoparticles selected from a group consisting essentially of carbon nanotubes and graphene, and the oxidized carbon atoms formed by ozonolysis of the nanoparticles.
The foregoing discussion along with the Figures discloses and describes various exemplary implementations. These implementations are not meant to limit the scope of coverage, but, instead, to assist in understanding the context of the language used in this specification and in the claims. Upon study of this disclosure and the exemplary implementations herein, one of ordinary skill in the art may readily recognize that various changes, modifications and variations can be made thereto without departing from the spirit and scope of the inventions as defined in the following claims.
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In various aspects, the processes disclosed herein may include the steps of inducing an electric field about a non-conductive substrate, and depositing functionalized nanoparticles upon the non conductive substrate by contacting a nanoparticle dispersion with the non-conductive substrate, the nanoparticle dispersion comprising functionalized nanoparticles having an electrical charge, the electric field drawing the functionalized nanoparticles to the non-conductive substrate. In various aspects, the related composition of matter disclosed herein comprise functionalized nanoparticles bonded to a surface of a non-conductive fiber, the surface of the non-conductive fiber comprising a sizing adhered to the surface of the non-conductive fiber. This Abstract is presented to meet requirements of 37 C.F.R. §1.72(b) only. This Abstract is not intended to identify key elements of the processes, and related apparatus and compositions of matter disclosed herein or to delineate the scope thereof.
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This is a continuation of application(s) Ser. No. 08/729,120 filed on Oct. 11, 1996 now abandoned.
FIELD OF THE INVENTION
The invention is directed generally to safety devices and, more particularly, to a movable barrier for protecting an enclosed work area.
BACKGROUND OF THE INVENTION
Area protection in the vicinity of automated manufacturing machines or in the vicinity of potentially hazardous processes is becoming increasingly important. Area protection is designed to prevent personnel, or even other automated equipment, from intentionally or accidentally entering a work area while a robot or other machine is performing its automatic function. Depending on the machine being enclosed, it may also be important for the area protection to provide a physical barrier between the machine and the surrounding area, as may be the case where an automatic welder is enclosed, and flying sparks and debris need to be contained. Area protection may also provide a barrier to radiation, or heat, or noise generated by the enclosed equipment. At the same time, it is desirable for any area protection system to allow unfettered access to the machine at appropriate time: between cycles, for replenishment of raw materials or work pieces, etc. Of course, area protection may also be used to enclose non-automated processes, such as manual welding stations and the like.
A variety of area protection systems have been used in the past. So-called light curtains comprise an array of photo-sensitive detectors surrounding a doorway or opening adjacent the automated machine. If the detectors sense the presence of an object (personnel or equipment) in the doorway, operation of the machine may be halted. While this may prevent accidental contact with the operating machine, light curtains do not provide a physical barrier against entry, nor do they offer a physical barrier to debris, sparks, radiation, etc. that may emanate from the enclosed equipment. Pressure-sensitive mats disposed on the floor adjacent a door or other opening near an automated machine serve the same purpose, but are similarly limited. Mechanical gates or barriers are also used. However, these tend to be slow-moving and may prevent visual access to the equipment being enclosed, as well as being relatively expensive. Movable, or portable barriers or screens may also be used, but these must be manually moved whenever access to the enclosed machine or work area is desired.
SUMMARY OF THE INVENTION
The present invention has as its primary object providing an improved area protection device. The rolling barrier according to the invention presents a physical barrier to entry into the work area when closed. Reinforcing bars extending across the barrier give it added strength, and allow the barrier to aid in preventing a person or equipment from accidentally falling or passing through the barrier, thus enhancing safety. The reinforcing bars would also allow the barrier to prevent a robotic machine or other automated equipment from accidentally leaving the enclosed area. The rolling barrier also provides a physical barrier between the enclosed machine or area and the surrounding environment. Depending on the nature of the machine, the barrier can be formed of a variety of materials to offer protection from radiation, sparks, debris, heat and/or noise produced by the machine or process. At the same time, the rolling barrier may also be moved rapidly to an open position to allow the ingress or egress of materials or personnel. Additionally, the rolling barrier may be provided with other desirable safety features. For example, the rolling barrier may be provided with a detector for detecting when the barrier is in the fully closed position. The enclosed machine could be coupled to the detector such that it could not operate unless the barrier were fully closed. Further, any movement of the barrier away from the closed position could be sensed, and could trigger the enclosed machinery to cease operation. Accordingly, if an accidental impact to the barrier occurred, moving the barrier slightly away from the closed position, operation of the machine could cease thus helping to prevent any injury or damage to the personnel or object causing the impact. Other interconnections between the rolling barrier and the enclosed equipment could also be employed.
In accordance with the mentioned objects, and other objects and advantages, the rolling barrier of the invention comprises a curtain formed of fabric or other material that rolls onto and off of a tube preferably disposed above a doorway or opening to, respectively, block and unblock the opening. The edges of the curtain are received within guideways disposed laterally of the curtain, and which guide the curtain edges to maintain the curtain in a planar orientation during travel. Barricade members extending across the curtain (and thus the opening when the barrier is in the closed or blocking position) have their ends disposed in the guideways as well. The barricade members reinforce the curtain and are intended to prevent personnel or objects from passing through the opening at least when the barrier is in the closed position. The engagement between the ends of the barricade members and the guideways helps in providing this function. The barrier also includes a detector for detecting when the curtain is in or at least approaching the fully closed position. The detector may advantageously be coupled to other electronics to control or regulate operation of the enclosed machine.
The invention will be described herein in reference to the appended drawings, wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevation of a rolling barrier according to one embodiment of the invention;
FIG. 2 is a side elevation of the barrier of FIG. 1;
FIGS. 3 and 4 are top and side elevational views, respectively of a side frame of the rolling barrier of FIG. 1;
FIG. 5 is a side section view of the curtain forming a portion of the rolling barrier according to the invention;
FIG. 6 is a front elevation view of the curtain showing FIG. 5; and
FIG. 7 is a front elevation view of a pair of rolling barriers according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A rolling barrier 10 according to the invention is shown in FIG. 1. A side-by-side pair of barriers 10 is shown in FIG. 7. Illustratively, the rolling barrier 10 could be disposed adjacent an automated manufacturing machine (depicted in block form as M) to limit access to the machine during its operation. In such an arrangement, the equipment would typically be surrounded by non-moving walls, screens or curtains, with the enclosure having one or more openings or doors to allow selective access to the equipment. The rolling barrier 10 according to the invention would be associated with one or more of such openings. Alternatively, non-moving walls, screens or curtains could form a work-cell, with the rolling barrier 10 (one or more) serving as a "door" to allow ingress and egress from the work cell. Other environments for the rolling barrier according to the invention will be apparent to one of skill in the art. For ease of reference, the area to which the barrier of the invention limits access will be referred to herein as the "enclosed area" regardless of whether the barrier in combination with other structures actually encloses an area.
The roller barrier 10, according to the invention, includes a curtain 12, which is mountable on a roller 14, typically disposed above the doorway or opening with which the barrier 10 is associated. Depending on the nature of the process being carried out in the enclosed area, and the type of protection to be offered by the rolling barrier 10 (flying debris, sparks, radiation, etc.), a variety of coatings or additional fabric layers may be added to a base curtain fabric. Presently, the preferred base fabric is a heavy-duty nylon based fabric manufactured by Cooley, Inc. under Model No. LK50KU. For protection when welding is being performed in the enclosed area, a high-temperature fabric may be attached to the curtain, illustratively Southern Manufacturing's material, designated by Model No. S/10A120 Blue. For even higher temperature applications (if adjacent furnaces or the like), a Silica fabric can be added to the curtain, illustratively 34ST fabric from Ametek. A window, or vision panel 13 may also be included. A support structure 15 is associated with the barrier 10, and serves as a support for the roller 14. Illustratively, the support structure 15 is in the form of sideframe members 16, 17, and a header member 18. A motor assembly 20 is also mounted on the support structure, illustratively on or adjacent the header 18, for rotationally driving the roller 14. The curtain 12 is attached to the roller 14 such that it winds onto and off of the roller 14 as the roller is rotated by the motor 20. Accordingly, the curtain is movable between a doorway or opening blocking position, and a range of unblocking positions (as in FIG. 1), in which the curtain 12 is wound on the roller 14. A "range" of unblocking positions are referred to since the doorway will be partially exposed before the curtain 12 is completely wound on the roller 14. In the fully blocking position, the leading edge of curtain 12 may touch the floor.
To provide added stability to the curtain 12, and to allow the curtain to provide an effective barrier against accidental or unauthorized entry into the enclosed area, the curtain includes two or more reinforcing members disposed across the curtain. "Accidental or unauthorized entry" is intended to encompass entry into the enclosed area when it is undesirable or dangerous, such as when automated equipment is operating. It is this unauthorized or accidental entry which the barrier according to the invention is intended to prevent. One of the reinforcing members is illustratively in the form of a barricade bar 30. In the present embodiment, three barricade bars 30, 34, 35 are disposed at different heights along the curtain 12. Each barricade bar is in the form of a steel pipe, and is slightly longer than the width of the door opening (i.e the distance between the inner edges of the sideframes 16, 17). The ends of the barricade bars 30, 34, 35 are thus disposed within the sideframes 16, 17. Engagement between the ends of the bars 30, 34, 35 and the sideframes, 16, 17 prevents the bars from moving out of the plane of the curtain when it is in the blocking position. The bars 30, 34, 35 may be either coupled to or received within the curtain 12. In the present embodiment, the bars 30, 34, 35 are sewn into pockets 36, 37, 38 formed on the curtain.
In the blocking position, the curtain 12, as reinforced by the barricade bars 30, 34, 35, serves as a barrier to entry to the enclosed area. If personnel or equipment accidentally run into the curtain while it is in the blocking or other positions, the bars 30, 34, 35 engage the sideframes, thereby remaining in the plane of the opening (an imaginary plane substantially parallel to the plane of the curtain in the blocking position). Since the bars are coupled to the curtain, this action effectively prevents the curtain from leaving the plane of the opening, and thus prevents the equipment or personnel from entering the enclosed area.
In order to receive and properly restrain the ends of the barricade bars 30, 34, 35 from moving out of the plane of the opening, the sideframes 16, 17 may have a generally u-shaped configuration, seen most clearly in FIG. 3. The "u" shape of the sideframes 16, 17 defines a slideway or central channel 40, within which the ends of the bars 30, 34, 35 ride. For impact forces on the curtain or the bars 30, 34, 35, the bars will engage the sidewalls 42 or 43 of the track 40. In the side view of FIG. 4, it can be seen that the sideframes 16, 17 may also taper from top to bottom such that the separation between the sidewalls decreases as the sideframes approach the floor. Also, as seen in FIG. 2, the sideframe may be attached for support to a support member such as 16a. The purpose of the taper is to eliminate unnecessary frictional drag between the curtain 12 and the sideframes 16, 17 while the curtain and bars are in the wider upper area of the sideframes. This reduced friction is desirable since the barrier according to the present invention falls largely by gravity to its closed position. At the same time, however, the sideframes 16, 17 taper to a narrower width at the bottom of the sideframe. Despite the possibility of increased friction in this area, the narrowing is desirable as it prevents the barrier in the blocking position from being able to move back and forth in the sideframes and helps maintain the barrier in the blocking position. In cases where the barrier 10 is serving as a barrier to sound or debris from inside the enclosed are, such prevention of back and forth movement is advantageous.
Rolling barrier 10 also includes a leading edge member 48. The leading edge member adds weight to the curtain, which is an advantage as the barrier of the present embodiment falls by gravity. The member also helps provide a seal against the floor in the vicinity of the opening. While a rigid member could be used, the leading edge member of the present embodiment is deformable. In particular, leading edge member 48 is in the form of a tube of sand or ground garnet received within a loop 49 at the leading edge of the curtain, as seen most clearly in FIG. 5. Use of a deformable member like the sand bag allows the leading edge to deform about an obstacle or even personnel that may accidentally be encountered as the barrier moves toward the closing position, or indeed when it is anywhere in its travel.
To enhance the safety provided by the barrier 10, and to prevent accidents or unauthorized entry to the enclosed area from causing a hazardous condition, the barrier 10 may include a detector for determining when the barrier is in the blocking position. The detector may be coupled to the machine or apparatus M inside of the enclosed area to ensure that operation does not begin until the barrier is in the blocking position. At the same time, the detector can detect when the barrier moves away from the unblocking position--such as by being powered open, or by virtue of an accidental impact on the door. The coupling between the detector and the enclosed equipment or process could be used to stop the operation for movement of the barrier away from the blocking position. In the present embodiment, the detector 50 is a magnetic proximity switch manufactured by Sentrol under Model No. 301-CT-06K/12K. A magnet 55 is illustratively carried on the curtain 12 as seen in FIG. 6, and the switch 50 is mounted on the sideframe 16 at the location shown in FIG. 4. In this embodiment, the switch and magnet are mounted about 12 inches above the floor. The barrier assuming the blocking position causes the magnet 55 and the switch 50 to align, thus switching the state of the switch 50. Electronics E (represented by a functional block in FIG. 1) may be coupled to the switch 50 to detect the signal generated by the change in state of the switch 50. This signal may in turn be used to control operation of the process or equipment in the enclosed area (shown graphically by the connection between electronics E and machine M). For example, power to an enclosed automated manufacturing machine may only be applied when the barrier is fully closed, etc. When the barrier 12 is raised, or for an accidental impact on the curtain or the barricade bars, the magnet 55 and the switch 50 will become misaligned. This, in turn, will cause the switch 50 to again switch states. This switch in state may be detected by the electronics E to cease operation of the process or equipment in the enclosed area or otherwise control the enclosed process or equipment. Alternatively or additionally, lights could flash, horns could sound, etc. The electronics E could be any of a wide variety of components, from simple switches or relays to more complex PLC's or microprocessors, as will be apparent to one of skill in the art.
There has thus been disclosed a rolling barrier providing enhanced safety in the form of reinforcing barricade bars and a blocking position detector.
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A rolling barrier including a curtain formed of fabric or other material that rolls onto and off of a tube preferably disposed above a doorway or opening to, respectively, block and unblock the opening, the edges of the curtain are received within guideways disposed laterally of the curtain, and which guide the curtain edges to maintain the curtain in a planar orientation during travel; barricade members extending across the curtain (and thus the opening when the barrier is in the closed or blocking position) have their ends disposed in the guideways as well to reinforce the curtain and prevent personnel or objects from passing through the opening at least when the barrier is in the closed position. The barrier may also include a detector for detecting when the door is in or at least approaching the fully closed position and coupled to other electronics to control or regulate operation of the enclosed machine.
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FIELD OF THE INVENTION
The present invention relates to novel anticancer agents, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, and their pharmaceutically acceptable solvates. The present invention more particularly relates to novel derivatives of Andrographolide, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, and their pharmaceutically acceptable solvates. The novel derivatives of Andrographolide have the general formula (I),
where R 1 , R 2 and R 3 may be same or different and independently represent hydrogen or substituted or unsubstituted groups selected from alkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, alkanoyl, alkenoyl, aroyl, heteroaroyl, sulfonyl group or a group —(CO)—W—R 4 where W represents O, S, or NR 5 , wherein R 5 represents hydrogen or (C 1 -C 6 )alkyl group, R 4 represents substituted or unsubstituted groups selected from alkyl, aryl, aroyl, or aralkyl or R 2 and R 3 together form a substituted or unsubstituted 3 to 7 membered cyclic structure containing carbon and oxygen atoms.
The andrographolide derivatives represented by general formula (I) defined above of the present invention are useful for treating cancer and other proliferative diseases including but not limited to herpes simplex virus types I and II, (HSVI and HSVII) and human immunodeficiency virus (HIV). The compounds of the present invention are also useful in the treatment of psoriasis, restonosis, atherosclerosis and other cardiovascular disorders. The compounds of the present invention are also useful as antiviral, antimalarial, antibacterial, hepatoprotective, immunomodulating agents and for treatment of metabolic disorders. The anticancer activity exhibited may be through cytotoxic activity, antiproliferation, cell cycle kinase inhibition or may be through cell differentiation.
The compounds of formula (I) are also useful for the treatment and/or prophylaxis of insulin resistance (type II diabetes), leptin resistance, impaired glucose tolerance, dyslipidemia, body weight reduction, disorders related to syndrome X such as hypertension, obesity, insulin resistance, coronary heart disease and other cardiovascular disorders.
The present invention also relates to pharmaceutical compositions containing compounds of general formula (I) or mixtures thereof.
The present invention also relates to a process for the preparation of the above defined compounds of general formula (I), their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, and their pharmaceutically acceptable solvates.
BACKGROUND OF THE INVENTION
The plant Andrographis paniculata is extensively used in traditional medicine as a bitter tonic, febrifuge and in bowel complaints ( Glossary of Indian Medicinal Plants., Ed. R. N. Chopra, S. L. Nayar, I. C. Chopra, p18, 1996; The useful plants of India, Ed. By S. B. Ambasta, p39, 1992). The plant is useful in the treatment of bacterial infections ( Int. J. Crude Drug Res. 1990, 28(4), p273-283; Drugs of the Future. 1990, 15(8) p809-816). It is reported to possess antimalarial ( Int. J. Pharmacognosy, 1992, 30(4), p263-274; J. Ethnopharmocol., 1999, 64(3), p249-254) and immunostimulant activity ( J. Nat. Prod., 1993, 56(7), p995-999). The plant has also been shown to be antithrombotic ( Chinese Medical Journal 1991, 104(9), p770-775) and inhibit stenosis and restenosis after angioplasty in the rat ( Chinese Medical Journal, 1994, 107(6), p464-470). It is also known that the plant extract and its constituents exhibit promising hepatoprotective activity ( Planta Medica, 1987, 53(2), p135-140). Significant attention has been paid by several research groups on A. paniculata in recent years due to its cytotoxic, antitumorogenic, cell differentiation inducing activities and anti-HIV activities.
Andrographolide having the formula (II),
the major constituent of the plant A. paniculata was first isolated by Gorter (Rec. trav. chim., 1911, 30, p151-160).
The extracts of the dried plant, which contain compounds of formula (III), have been assayed for the ability to decrease expression and phosphorylation of p34 cdc2 kinase, cyclin B and c-Mos for treating or preventing pathogenecity of diseases such as AIDS, Alzheimer's disease and hepatitis (WO 96/17605).
Cell cycle kinases are naturally occurring enzymes involved in regulation of the cell cycle ( Progress in Cell Cycle Research, 1995, 1, p351-363). Typical enzymes include the cyclin-dependent kinases (cdk) cdk1, cdk2, cdk4, cdk5, cdk6 and wee-1 kinase. Increased activity or temporarily abnormal activation of these kinases has been shown to result in development of tumors and other proliferative disorders such as restenosis. Compounds that inhibit cdks, either by blocking the interaction between a cyclin and its kinase partner or by binding to and inactivating the kinase, cause inhibition of cell proliferation and are thus useful for treating tumors or other abnormally proliferating cells.
The extract of A. paniculata was found to show significant cytotoxic activity against KB and P388 cells. Interestingly, Andrographolide of the formula II, has been shown for the first time to have potent cytotoxic activity against KB as well as P388 lymphocytic leukemia, where as 14-deoxy-11,12-didehydroandrographolide and neoandrographolide having the formulae IV & V
where R represents β-D-glucose moiety, have shown no cytotoxic activity in tumor cell lines ( J. Sci. Soc. Thailand, 1992, 18, p187-194).
The methanolic extract of the aerial parts of A. paniculata Nees showed potent cell differentiation inducing activity on mouse myeloid leukemia (M1) cells ( Chem. Pharm. Bull. 1994, 42(6) 1216-1225).
Japanese patent application JP 63-88124, discloses a mixture of at least two compounds of formula VIa and VIb,
where R 1 , R 2 , R 3 , R 4 and R 5 represent hydrogen or lower alkanoyl group and their activity as antitumorogenic agents.
DASM (Dehydroandrographolide Succinic acid monoester) prepared from Andrographolide of the formula II is found to be inhibiting HIV virus and nontoxic to the H9 cell at the concentrations of 50-200 μg/ml and was inhibitory to HIV-1(IIIB) at the minimal concentration of 1.6-3.1 μg/ml ( Proc. Soc. Exp. Biol. Med., 1991, 197, p59-66).
The plant Andrographis paniculata is also reported to inhibit proprotein convertases-1, -7 and furin possibly by suppressing the proteolytic cleavage of envelope glycoprotein gp 160 of HIV, which is known to be PC-mediated, particularly by furin and PC ( Biochem. J., 1999, 338, 107-113)
In International patent application WO 91/01742, compositions containing one or more ingredients obtained from the plants Valeariana officinalis and/or A. paniculata were disclosed to have antiviral, antineoplastic, antibacterial and immunomodulatory activity.
Although several novel Andrographolide derivatives have been prepared, screened and reported in the above said prior-art literature for their anticancer activity, they are not showing interesting activity.
OBJECTIVE OF THE INVENTION
With an objective of preparing novel andrographolide derivatives useful for treating cancer, HSV, HIV, psoriasis, restonosis, atherosclerosis, cardiovascular disorders and as antiviral, antimalarial, antibacterial, hepatoprotective, immunomodulating agents and for treatment of metabolic disorders, which are potent at lower doses and having better efficacy with lower toxicity, we focussed our research efforts in preparing the novel Andrographolide derivatives of the formula (I) as defined above.
The main objective of the present invention is, therefore, to provide novel Andrographolide derivatives of the formula (I) as defined above, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates and pharmaceutical compositions containing them or their mixtures.
Another objective of the present invention is to provide pharmaceutical compositions containing compounds of the formula (I), their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates, containing them or their mixtures in combination with suitable carriers, solvents, diluents and other media normally employed in preparing such compositions.
Still another objective of the present invention is to provide pharmaceutical compositions containing compounds of the formula (I), their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates, containing them or their mixtures in combination with one or more pharmaceutically acceptable active compounds with suitable carriers, solvents, diluents and other media normally employed in preparing such compositions.
Still another objective of the present invention is to provide a process for the preparation of Andrographolide derivatives of the formula (I) as defined above, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates and pharmaceutical compositions containing them or their mixtures having enhanced activity with little or no toxic effect or reduced toxic effect.
DETAILED DESCRIPTION OF THE INVENTION
Accordingly, the novel derivatives of Andrographolide of the present invention have the general formula (I)
where R 1 , R 2 and R 3 may be same or different and independently represent hydrogen or substituted or unsubstituted groups selected from alkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, alkanoyl, alkenoyl, aroyl, heteroaroyl, sulfonyl group or a group —(CO)—W—R 4 where W represents O, S, or NR 5 , wherein R 5 represents hydrogen or (C 1 -C 6 )alkyl group, R 4 represents substituted or unsubstituted groups selected from alkyl, aryl, aroyl, or aralkyl or R 2 and R 3 together form a substituted or unsubstituted 3 to 7 membered cyclic structure containing carbon and oxygen atoms; their stereoisomers, their polymorphs, their pharmaceutically acceptable salts and their pharmaceutically acceptable solvates.
Suitable groups represented by R 1 , R 2 and R 3 include substituted or unsubstituted, linear or branched (C 1 -C 8 )alkyl group such as methyl, ethyl, n-propyl, iso-propyl and the like; aryl group such as phenyl, substituted phenyl and the like, the aryl group may be substituted; heteroaryl group such as pyridyl, furyl, thiophenyl and the like, the heteroaryl group may be substituted; aralkyl such as benzyl, phenethyl and the like, the aralkyl group may be substituted; heteroaralkyl group such as pyridylmethyl, pyridylethyl, furanmethyl, furanethyl and the like, the heteroaralkyl group may be substituted; (C 2 -C 8 ) alkanoyl group such as ethanoyl, propanoyl, butanoyl and the like, the (C 2 -C 8 ) alkanoyl group may be substituted; (C 3 -C 8 ) alkenoyl group such as propenoyl, butenoyl, pentenoyl and the like, (C 3 -C 8 )alkenoyl group may be substituted; aroyl group such as benzoyl and the like, the aroyl group may be substituted; heteroaroyl group such as pyridyl carbonyl, furyl carbonyl and the like; the heteroaroyl group may be substituted; and sulfonyl group such as methanesulfonyl, benzenesulfonyl, p-toluenesulfonyl and the like, the sulfonyl group may be substituted.
The substituents on R 1 , R 2 and R 3 may be selected from cyano, hydroxy, nitro, halogen atom such as fluorine, chlorine or bromine; substituted or unsubstituted group selected from (C 1 -C 8 )alkyl such as methyl, ethyl, propyl, butyl and the like, the substituents of (C 1 -C 8 )alkyl may be selected from halogen atom, hydroxy, nitro, cyano, amino, phenyl or (C 1 -C 6 )alkoxy groups; amino, mono or disubstituted amino group, the substituents of the amino group may be selected from hydroxy or (C 1 -C 6 ) alkoxy groups; alkanoyl group such as ethanoyl, propanoyl, butanoyl and the like; (C 1 -C 6 ) alkoxy group such as methoxy, ethoxy, propyloxy, butyloxy and the like; aroyl group such as benzoyl and the like; acyloxy group such as acetyloxy, propanoyloxy, butanoyloxy and the like; aryl group such as phenyl, naphthyl and the like, the aryl group may be mono or disubstituted and the substituents may be selected from (C 1 -C 6 )alkyl, halogen atom, amino, cyano, hydroxy, nitro, trifluoroethyl, thio, thioalkyl, alkylthio and (C 1 -C 6 )alkoxy groups; heteroaryl group such as pyridyl, furyl, thienyl and the like; mono(C 1 -C 6 )alkylamino group such as CH 3 NH, C 2 H 5 NH, C 3 H 7 NH, and C 6 H 13 NH and the like; di(C 1 -C 6 )alkylamino group such as (CH 3 ) 2 N, (C 2 H 5 )NCH 3 and the like; acylamino groups such as CH 3 CONH, C 2 H 5 CONH, C 3 H 7 CONH, C 4 H 9 CONH, and C 6 H 5 CONH; arylamino group such as C 6 H 5 NH, (C 6 H 5 )NCH 3 , C 6 H 4 (CH 3 )NH, C 6 H 4 (Hal)NH and the like; aralkylamino group such as C 6 H 5 CH 2 NH, C 6 H 5 CH 2 CH 2 NH, C 6 H 5 CH 2 NCH 3 and the like; alkoxycarbonylamino group such as C 2 H 5 OCONH, CH 3 OCONH and the like; aryloxycarbonylamino group such as C 6 H 5 OCONH, C 6 H 5 OCONCH 3 , C 6 H 5 OCONC 2 H 5 , C 6 H 4 (CH 3 )OCONH, C 6 H 4 (OCH 3 )OCONH, and the like; aralkoxycarbonylamino group such as C 6 H 5 CH 2 OCONH, C 6 H 5 CH 2 CH 2 OCONH, C 6 H 5 CH 2 OCON(CH 3 ), C 6 H 5 CH 2 OCON(C 2 H 5 ), C 6 H 4 (CH 3 )CH 2 OCONH, C 6 H 4 (OCH 3 )CH 2 OCONH and the like; or COOR, where R represents hydrogen or (C 1 -C 6 )alkyl groups.
When the aryl group is disubstituted, the two substituents on the adjacent carbon atoms may form a linking group such as —X—CH 2 —Y—, or —X—CH 2 —CH 2 —Y—, where X and Y may be same or different and independently represent O, NH, S or CH 2 .
When the groups represented by R 1 , R 2 or R 3 are multisubstituted, the substituents present on the two adjacent carbons may form a linking group —X—(CR 6 R 7 ) n —Y— where R 6 and R 7 represent (C 1 -C 8 )alkyl such as methyl, ethyl and the like, X and Y may be same or different and independently represent C, O, S, or NH; and n=1 or 2.
Suitable groups represented by R 4 include substituted or unsubstituted (C 1 -C 6 )alkyl such as methyl, ethyl, n-propyl and the like; aryl group such as phenyl, substituted phenyl and the like, the aryl group may be substituted; aralkyl such as benzyl, phenethyl and the like, the aralkyl group may be substituted; and aroyl group such as benzoyl and the like, the aroyl group may be substituted. The substituents on the alkyl group, aromatic moiety of the aryl group, aralkyl group or aroyl group include halogen atom such as fluorine, chlorine, and bromine; amino group, cyano, hydroxy, nitro, trifluoroethyl, (C 1 -C 6 )alkyl, and (C 1 -C 6 )alkoxy.
Pharmaceutically acceptable salts forming part of this invention include salts of the carboxylic acid moiety such as alkali metal salts like Li, Na, and K salts, alkaline earth metal salts like Ca and Mg salts, salts of organic bases such as lysine, arginine, guanidine, diethanolamine, choline and the like, ammonium or substituted ammonium salts, and aluminum salts. Salts may include acid addition salts where appropriate which include, sulphates, nitrates, phosphates, perchlorates, borates, hydrohalides, acetates, tartrates, maleates, citrates, succinates, palmoates, methanesulphonates, benzoates, salicylates, hydroxynaphthoates, benzenesulfonates, ascorbates, glycerophosphates, ketoglutarates and the like. Pharmaceutically acceptable solvates may be hydrates or comprising other solvents of crystallization such as alcohols.
Particularly useful compounds according to present invention include;
8,17-epoxy andrographolide;
3,14,19-triacetyl 8,17-epoxy andrographolide;
3,14,19-tripropionyl 8,17-epoxyandrographolide;
3,14,19-tris chloro acetyl 8,17-epoxy andrographolide;
8,17-epoxy andrographolide 3,19-acetonide;
14-methoxy 3,19-diacetyl 8,17-epoxy andrographolide;
14-cinnamoyl 3,19-dihydroxy 8,17-epoxy andrographolide;
14-cinnamoyl 3,19-dipropionyl 8,17-epoxy andrographolide;
14-[4′-methoxycinnamoyl]3,19-dipropionyl 8,17-epoxy andrographolide;
8,17-epoxy 14-[3′,4′-dimethoxycinnamoyl]3,19-dipropionyl andrographolide;
14-[3′,4′-methylene dioxy cinnamoyl]3,19-dipropionyl 8,17-epoxy andrographolide;
14-[N-Boc glycinyl]8,17-epoxy andrographolide;
14-[N-Boc glycinyl]3,19-dipropionyl 8,17-epoxy andrographolide;
19-trityl 8,17-epoxy andrographolide;
3-acetyl 8,17-epoxy Andrographolide;
3,14-diacetyl 8,17-epoxy Andrographolide;
14,19-diacetyl 8,17-epoxy Andrographolide;
3,14-dipropionyl 8,17-epoxy Andrographolide;
14-[4S,5R(N-1-butoxycarbonyl)-2,2-dimethyl-4-phenyl-5-oxazolidine]carbonyl-3,19-diacetyl-8,17-epoxy andrographolide; and
14-[2′-acetoxy-3′-N-acetylamino-3′-phenyl]propanoyl-3,19-diacetyl-3,17-epoxyandrographolide.
Cinnamoyl is propenoyl substituted by phenyl.
The present invention also provides a process for the preparation of novel derivatives of Andrographolide of the general formula (I) where R 1 , R 2 and R 3 may be same or different and independently represent hydrogen or substituted or unsubstituted groups selected from alkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, alkanoyl, alkenoyl, aroyl, heteroaroyl, sulfonyl group or a group —(CO)—W—R 4 where W represents O, S, or NR 5 , wherein R 5 represents hydrogen or (C 1 -C 6 )alkyl group, R 4 represents substituted or unsubstituted groups selected from alkyl, aryl, aroyl, or aralkyl or R 2 and R 3 together form a substituted or unsubstituted 3 to 7 membered cyclic structure containing carbon and oxygen atoms, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts and their pharmaceutically acceptable solvates, which comprises:
(i) epoxidising Andrographolide of the formula (II)
by conventional methods to form a compound of formula (VII),
(ii) reacting the compound of formula (VII) with R 1 —L, R 2 —L and R 3 —L, where R 1 , R 2 and R 3 may be same or different and independently represent hydrogen or substituted or unsubstituted groups selected from alkyl, aryl, heteroaryl, aralkyl, heteroaralkyl, alkanoyl, alkenoyl, aroyl, heteroaroyl, sulfonyl group or a group —(CO)—W—R 4 where W represents O, S, or NR 5 , wherein R 5 represents hydrogen or (C 1 -C 6 )alkyl group, R 4 represents substituted or unsubstituted groups selected from alkyl, aryl, aroyl, or aralkyl and L represents a leaving group such as hydroxy, halogen atom like fluorine, chlorine, bromine, or iodine; p-toluenesulfonate, methanesulfonate, trifluoromethanesulfonate, acyl group such as acetate, propanoate, butanoate and the like, to produce a compound of formula (I), and if desired,
(iii) protecting the hydroxy groups present on carbons 3 or 19 or 3 and 19 together in the compound of formula (VII) with suitable protecting groups using conventional methods to produce a compound of formula (VIII),
where P 1 and P 2 may be same or different and represent hydrogen, trityl, t-butyl dimethyl silyl, pivaloyl and the like, or esters such as acetate, propionate, benzoate and the like or together may form methylene dioxy, acetonide, benzilidine and the like, (iv) reacting the compound of formula (VIII) defined above with compound of formula (IX)
R 1 —L (IX)
where R 1 and L have the meanings given above to produce a compound of formula (X),
where R 1 , P 1 and P 2 are as defined earlier,
(v) deprotecting the compound of formula (X) by conventional methods to produce a compound of formula (XI),
where R 1 has the meaning given above,
(vi) reacting the compound of formula (XI) where R 1 has the meaning given above with R 2 —L and/or R 3 —L, where R 2 , R 3 and L are as defined above to produce a compound of formula (I), and if desired,
(vii) converting compound of formula (I) into their stereoisomers, pharmaceutical salts or pharmaceutical solvates by conventional methods.
The epoxidation of a compound of formula (II) may be carried out in the presence of oxidising agents such as per acids which may selected from m-chloroperbenzoicacid, p-nitro perbenzoic acid, mono per phthalic acid, peroxy lauric acid, peroxy acetic acid, magnesium mono per phthalate; peroxides such as hydrogen peroxide of various strengths, t-butyl hydroperoxide and the like; iodine and bromine in presence of silver salts and other epoxidising agents such as N-chlorosuccinimide, N-bromosuccinimide, N-bromoacetamide, or dimethyl dioxirane may be used. During the epoxidation conventional solvents such as methanol, ethanol, chloroform, dichloromethane, tetrahydrofuran, dimethyl formamide (DMF), dioxane and the like or their mixtures may be used. The reaction may be carried out at a temperature in the range of −20° C. to 80° C., preferably in the range of −20° C. to 60° C.
The reaction of a compound of formula (VII) with R 1 —L, R 2 —L and R 3 —L to produce a compound of formula (I) may be carried out in the presence of dicyclohexylcarbo-diimide (DCC), diethyl azadicarboxylate (DEAD), diisopropyl azadicarboxylate (DLAD), ethyl chloro formate or the like. The reaction may be carried out in the absence or presence of a base selected from triethylamine, pyridine, dimethyl aminopyridine and the like. The reaction may also be carried out in the presence of an acid such as H 2 SO 4 , HCl, HClO 4 , TFA, formic acid, Lewis acids like BF 3 , ZnCl 2 etc. The reaction may be carried out in the presence of solvents such as dichloromethane, chloroform, C 6 H 6 , dimethyl sulfoxide, methanol, ethanol and the like or mixtures thereof. The reaction may be carried out at a temperature in the range of −70° C. to 200° C., preferably at a temperature in the range of −70° C. to 160° C. and the reaction time may range from 2 to 12 h, preferably from 2 to 10 h.
The protection of a compound of formula (VII) may be carried out using trityl chloride, t-butyldimethylsilyl chloride, pivaloyl chloride, dimethylsulfoxide, acetone, 2,2-dimethoxy propane, trimethyl ortho acetate, benzaldehyde, p-methoxy benzaldehyde, acetophenone and the like. The reaction may be carried out in the presence of a suitable catalyst such as SOCl 2 , H 2 SO 4 , HClO 4 , pyridinium p-toluene sulphonate, pyridine, p-toluene sulfonic acid, dimethyl aminopyridine, and the like. The reaction may be carried out in the absence or presence of suitable solvent such as benzene, DMF, dimethyl-sulfoxide (DMSO), acetonitrile, dichloromethane (DCM), and the like or mixtures thereof. The reaction may be carried out at a temperature in the range of 0° C. to 60° C., preferably at a temperature in the range of 20° C. to 40° C. The reaction time may range from 2 to 6 h, preferably from 2 to 4 h.
The reaction of a compound of formula (VIII) with a compound of formula (IX) may be carried out in the presence of dicyclohexylcarbodiimide (DCC), diethyl azadicarboxylate (DEAD), diisopropyl azadicarboxylate (DIAD), ethyl chloro formate and the like. The reaction may be carried out in the absence or presence of a base selected from triethylamine, pyridine, dimethyl aminopyridine and the like. The reaction may also be carried out in the presence of an acid such as H 2 SO 4 , HCl, HClO 4 , TFA, formic acid, and Lewis acids like BF 3 , ZnCl 2 etc. The reaction may be carried out in the presence of solvents such as dichloromethane, chloroform, C 6 H 6 , dimethyl sulfoxide, methanol, ethanol and the like or mixtures thereof. The reaction may be carried out at a temperature in the range of −70° C. to 200° C., preferably at a temperature in the range of −70° C. to 160° C. and the reaction time may range from 2 to 12 h, preferably from 2 to 10 h.
The deprotection of a compound of formula (X) to produce a compound of formula (XI) may be carried out using deprotecting agent such as acetic acid, hydrochloric acid, formic acid, trifluoroacetic acid and the like. The reaction may be carried in the presence of suitable solvent such as water, THF, dioxane, DCM, CHCl 3 , methanol and the like or mixtures thereof. The reaction may be carried out at a temperature in the range of 0° C. to 60° C., preferably at a temperature in the range of 20° C. to 40° C. The reaction time may range from 2 to 6 h, preferably from 2 to 4 h.
The reaction of compound of formula (XI) with R 2 —L and/or R 3 —L, to produce a compound of formula (I) may be carried out in the presence of dicyclohexylcarbodiimide (DCC), diethyl azadicarboxylate (DEAD), diisopropyl azadicarboxylate (DIAD), ethyl chloroformate and the like. The reaction may be carried out in the absence or presence of a base selected from triethylamine, pyridine, dimethyl aminopyridine and the like. The reaction may also be carried out in the presence of an acid such as H 2 SO 4 , HCl, HClO 4 , TFA, formic acid, and Lewis acids like BF 3 , ZnCl 2 etc. The reaction may be carried out in the presence of solvents such as dichloromethane, chloroform, C 6 H 6 , dimethyl sulfoxide, methanol, ethanol and the like or mixtures thereof. The reaction may be carried out at a temperature in the range of −70° C. to 200° C., preferably at a temperature in the range of −70° C. to 160° C. and the reaction time may range from 2 to 12 h, preferably from 2to 10 h.
The pharmaceutically acceptable salts are prepared by reacting the compounds of formula (I) with 1 to 4 equivalents of a base such as sodium hydroxide, sodium methoxide, sodium hydride, potassium t-butoxide, calcium hydroxide, magnesium hydroxide and the like, in solvents like ether, THF, methanol, t-butanol, dioxane, isopropanol, ethanol etc. A mixture of solvents may be used. Organic bases like lysine, arginine, diethanolamine, choline, guanidine and their derivatives etc. may also be used. Alternatively, acid addition salts wherever applicable are prepared by treatment with acids such as hydrochloric acid, phosphoric acid, p-toluenesulphonic acid, methanesulfonic acid, acetic acid, citric acid, maleic acid, salicylic acid, hydroxynaphthoic acid, ascorbic acid, palmitic acid, succinic acid, benzoic acid, benzenesulfonic acid, tartaric acid and the like in solvents like ethyl acetate, ether, alcohols, acetone, THF, dioxane etc. A mixture of solvents may also be used.
The stereoisomers of the compounds of formula (I) forming part of this invention may be prepared by using reactants in their single enantiomeric form in the process wherever possible or by conducting the reaction in the presence of reagents or catalysts in their single enantiomer form or by resolving the mixture of stereoisomers by conventional methods. Some of the preferred methods include use of microbial resolution, resolving the diastereomeric salts formed with chiral acids such as mandelic acid, camphorsulfonic acid, tartaric acid, lactic acid and the like or chiral bases such as brucine, cinchona alkaloids and their derivatives and the like. Commonly used methods are compiled by Jaques et al in “Enantiomers, Racemates and Resolution” (Wiley Interscience, 1981).
Various polymorphs of the compounds of general formula (I) forming part of this invention may be prepared by crystallization of compound of formula (I) under different conditions. For example, using different solvents commonly used or their mixtures for recrystallization; crystallizations at different temperatures; various modes of cooling, ranging from very fast to very slow cooling during crystallizations. Polymorphs may also be obtained by heating or melting the compound followed by gradual or slow cooling. The presence of polymorphs may be determined by solid probe nmr spectroscopy, ir spectroscopy, differential scanning calorimetry, powder X-ray data or such other techniques.
Pharmaceutically acceptable solvates can be prepared by conventional methods such as dissolving the compounds of formula (I) in solvents such as water, methanol, ethanol etc., preferably water and recrystallizing by using different crystallization techniques.
The present invention also envisages pharmaceutical compositions containing compounds of the formula (I) defined earlier, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates or their mixtures in combination with the usual pharmaceutically employed carriers, solvents, diluents and other media normally employed in preparing such compositions. The compositions may contain other active ingredients.
The pharmaceutical composition may be in the forms normally employed, such as tablets, capsules, powders, syrups, solutions, suspensions and the like, may contain flavourants, sweeteners etc. in suitable solid or liquid carriers or diluents, or in suitable sterile media to form injectable solutions or suspensions. Such compositions typically contain from 1 to 25%, preferably 1 to 15% by weight of active compound, the remainder of the composition may be pharmaceutically acceptable carriers, diluents or solvents and may also contain other active ingredients.
The compounds of the formula (I) as defined above are clinically administered to mammals, including man, via either oral or parenteral routes. Administration by the oral route is preferred, being more convenient and avoiding the possible pain and irritation of injection. However, in circumstances where the patient cannot swallow the medication, or absorption following oral administration is impaired, as by disease or other abnormality, it is essential that the drug be administered parenterally. By either route, the dosage is in the range of about 0.01 to about 100 mg/kg body weight of the subject per day or preferably about 0.01 to about 30 mg/kg body weight per day administered singly or as a divided dose. However, the optimum dosage for the individual subject being treated will be determined by the person responsible for treatment, generally smaller doses being administered initially and thereafter increments made to determine the most suitable dosage.
Suitable pharmaceutically acceptable carriers include solid fillers or diluents and sterile aqueous or organic solutions. The active compound will be present in such pharmaceutical compositions in the amounts sufficient to provide the desired dosage in the range as described above. Thus, for oral administration, the compounds can be combined with a suitable solid or liquid carrier or diluent to form capsules, tablets, powders, syrups, solutions, suspensions and the like. The pharmaceutical compositions, may, if desired, contain additional components such as flavourants, sweeteners, excipients and the like. For parenteral administration, the compounds can be combined with sterile aqueous or organic media to form injectable solutions or suspensions. For example, solutions in sesame or peanut oil, aqueous propylene glycol and the like can be used, as well as aqueous solutions of water-soluble pharmaceutically-acceptable acid addition salts or salts with base of the compounds. The injectable solutions prepared in this manner can then be administered intravenously, intraperitoneally, subcutaneously, or intramuscularly, with intramuscular administration being preferred in humans.
The invention is explained in detail in the examples given below which are provided by way of illustration only and therefore should not be construed to limit the scope of the invention.
EXAMPLE 1
PREPARATION OF 8,17-EPOXY ANDROGRAPHOLIDE
Andrographolide (500 mg) was dissolved in chloroform (50 ml with few drops of methanol) and to it was added meta chloro perbenzoic acid (980 mg) and the mixture stirred for 4 hours. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was concentrated and chromatographed over a column of silicagel (60-120 mesh; 50 grams) with chloroform acetone (75-25) as solvent system to obtain the title compound as a colourless solid (300 mg, 57%). m.p. 170° C.
1 H NMR: δ6.85 (1H, t, J=10 Hz, C-12 H), 5.00 (1H, d, J=5.8 Hz, C-14H), 4.40-4.00 (m), 3.40 (1H, t, C-3H), 3.25 (1H, d, C-19 Hb), 2.75 (2H, dd, J=12.4 Hz, C-17),
EXAMPLE 2
PREPARATION OF 3,14,19-TRIACETYL 8,17-EPOXY ANDROGRAPHOLIDE
8,17-epoxy andrographolide (100 mg) obtained in Example 1 above was taken in 2 ml of acetic anhydride and refluxed for 5 minutes. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was diluted with solvent ether, washed with water and dried over Na 2 SO 4 and concentrated. The residue obtained was chromatographed over a column of silicagel (60-120 mesh) with light petrol:ethyl acetate (65:35) as the solvent system to afford the title compound as a colourless solid (90 mg, 67%). mp: 195° C.
1 H NMR: δ7.09 (1H, t, J=10 Hz, C-12 H), 5.88 (1H, d, J=5.8 Hz, C-14 H), 4.55 (1H, C-3H), 4.5(1H, C-15Ha), 4.29(1H,C-19Ha), 4.21 (1H, C-15 Hb), 4.16(1H, C-19Hb), 2.6(2H, dd, J=12,4 Hz, C-17H), 2.11 (3H, S, OAc), 2.05(6H, s, OAc)
EXAMPLE 3
PREPARATION OF 3,14,19-TRIPROPIONYL 8,17-EPOXYANDROGRAPHOLIDE
8,17-epoxyandrographolide (200 mg) obtained in Example 1 was taken in propionic anhydride (3 ml) and the mixture was refluxed for 5 minutes. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was poured into water (50 ml) and extracted with dichloromethane. The organic layer was dried over Na 2 SO 4 and concentrated. The concentrated residue was recrystallised with ethanol to yield the title compound as colourless solid (115 mg, 39%) m.p. 119° C.
1 H NMR: δ7.1 (1H, t, J=10 Hz, C-12 H), 5.9 (1H, d, J=5.8 Hz, C-14 H), 4.7-4.5 (m), 4.4 -4.0 (m), 2.6 (2H, dd, J=12, 4 Hz, C-17 H), 2.5 -2.3 (m, Propyl)
EXAMPLE 4
PREPARATION OF 3,14,19-TRIS CHLORO ACETYL 8,17-EPOXY ANDROGRAPHOLIDE
8,17-epoxy andrographolide (400 mg) obtained in Example 1, chloro acetic acid (770 mg), dicyclohexylcarbodiimide (1.6 gms) and triethyl amine (1 ml) were taken in dichloromethane (20 ml) and the mixture stirred for 1 hour at room temperature. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was filtered to remove the insoluble urea, diluted with dichloromethane, washed with saturated NaHCO 3 and water successively. The organic layer was dried over Na 2 SO 4 and concentrated. The residue obtained was chromatographed over a column of silicagel (60-120 mesh) with chloroform:acetone (98:2) as the eluent to yield the title compound as a colourless solid (200 mg, 31%) m.p 180° C.
1 HNMR: δ7.1 (1H, t, J=10 Hz, C-12 H), 6.0 (1H, d, J=5.8 Hz, C-14 H), 4.7-4.5 (m), 4.4-4.0 (m), 2.6 (2H, dd, J=12, 4 Hz, C-17 H).
EXAMPLE 5
PREPARATION OF 8,17-EPOXY ANDROGRAPHOLIDE 3,19-ACETONIDE
8,17-epoxy andrographolide (2 g) was taken in a mixture of 2,2-dimethoxy propane (15 ml) and DMSO (2 ml). The mixture was heated to about 45° C. until a clear solution was obtained. Then the solution was cooled to room temperature, a catalytic amount of pyridinium p-toluene sulphonate (PPTS) was added and the contents were stirred for one hour at room temperature. After the reaction was completed, the reaction mixture was quenched with triethylamine (2 ml), poured into water (100 ml), extracted with DCM (3×200 ml). The organic layer was dried over sodium sulfate and concentrated to dryness. The residue was chromatographed over a column of silicagel with chloroform:acetone (95:5) as the eluent to obtain 8,17-epoxy andrographolide 3,19-acetonide (2 g, 90%). m.p: 179° C.
1 H NMR: δ6.8 (1H, m, C-12), 5.0 (1H, d, C-14), 4.4-4.0 (m), 3.95 (1H, d, C-19Ha), 3.55 (1H, dd, C-33), 3.2 (1H, d, C-19 Hb), 2.8 (2H, dd, J=12, 4 Hz, C-17 H), 1.4 (3H, s) and 1.35 (3H, s) (Acetonide).
EXAMPLE 6
PREPARATION OF 14-METHOXY 3,19-DIACETYL 8,17-EPOXY ANDROGRAPHOLIDE
Step 1
14-METHOXY 8,17-EPOXY ANDROGRAPHOLIDE 3,19-ACETONIDE
8,17-epoxy andrographolide 3,19-acetonide (500 mg) was treated with calcium sulphate (550 mg) in 5 ml of methyl iodide. The mixture was treated with silver oxide (465 mg) and the contents were stirred at room temperature for 28 hours. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was extracted with dichloromethane and filtered through celite. The filtrate was concentrated, chromatographed over a column of silica gel (60-120) with chloroform: acetone mixture (96:4) to yield 14-methoxy 8,17-epoxy andrographolide 3,19-acetonide (350 mg, 67%).
Step 2
14-METHOXY 8,17-EPOXY ANDROGRAPHOLIDE
14-methoxy 8,17-epoxyandrographolide 3,19-acetonide (350 mg) obtained in step 1 above was stirred with 100 ml of 70% aqueous acetic acid for 10 min. After completion of the reaction the reaction mixture was neutralized with sodium bicarbonate and extracted with dichloromethane. The organic layer was dried with sodium sulphate and concentrated to yield crude 14-methoxy 8,17-epoxy andrographolide (300 mg, 95%).
Step 3
14-METHOXY 3,19-DIACETYL 8,17-EPOXY ANDROGRAPHOLIDE
14-Methoxy 8,17-epoxy andrographolide (300 mg) obtained above was refluxed in acetic anhydride (10 ml) for about 10 min. After completion of the reaction the reaction mixture was poured into water and extracted with dichloromethane. The residue obtained after removing the solvent was purified by flash chromatography over a column of silica gel (230-400 mesh) with pet. ether:ethyl acetate (65:35) to yield 14-methoxy 3,19-diacetyl 8,17-epoxy andrographolide (260 mg, 71%). m.p. 164° C.
1 H NMR: δ7.1 (1H, t, C=12), 4.7-4.6 (m), 4.4 & 4.15 (2H, dd, C-19), 4.35 (2H, d, C-15), 3.3 (3H, s, —OMe), 2.65 (2H, dd, C-17), 2.10, 2.15 (3H each, s, OAc).
EXAMPLE 7
PREPARATION OF 14-CINNAMOYL 3,19-DIHYDROXY 8,17-EPOXY ANDROGRAPHOLIDE
Step 1
14-CINNAMOYL 8,17-EPOXY ANDROGRAPHOLIDE 3,19-ACETONIDE
Mixed anhydride of cinnamic acid and ethyl chloro formate was prepared by adding 270 μl of ethyl chloro formate and 500 μl of triethyl amine in succession to a solution of cinnamic acid (370 mg) in 25 ml of dichloromethane at 0° C. under nitrogen atmosphere. The mixture was stirred for 30 minutes at 0° C. To this 500 mg of 8,17-epoxy andrographolide 3,19-acetonide in dichloromethane was added dropwise. The resultant mixture was stirred at room temperature for about 12 hours. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was diluted with dichloromethane, washed with saturated NaHCO 3 followed by water and dried over Na 2 SO 4 and concentrated. The residue was chromatographed over a column of silica gel (230-400 mesh) using chloroform:acetone (98:2) as the eluting solvent.
Step 2
14-CINNAMOYL 8,17-EPOXY ANDROGRAPHOLIDE
14-Cinnamoyl ester of 8,17-epoxy andrographolide 3,19-acetonide obtained above (300 mg) was treated with 70% aq. acetic acid to yield the title compound as a colourless solid (250 mg) m.p. 97° C.
1 H NMR: δ7.7 (1H, d, J=20 Hz, C-3′), 7.5 (2H, m), 7.35(3H, m), 7.05 (1H, triplet, C-12), 6.4(1H, d, J=20 Hz, C-2′), 6.0 (1H, d, J=5.8 Hz, C-14), 4.6-4.5 (m), 4.3-4.1 (m), 3.4 (m, C-3), 3.3 (d, C-19 Hb), 2.5 (2H, dd, C-17H).
EXAMPLE 8
PREPARATION OF 14-CINNAMOYL 3,19-DIPROPIONYL 8,17-EPOXY ANDROGRAPHOLIDE
250 mg of the 14-cinnamoyl 8,17-epoxy andrographolide obtained in Example 7 was refluxed in 10 ml of propionic anhydride for 15 minutes. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was poured into water and extracted with dichloromethane. The dichloromethane layer was dried over sodium sulfate and concentrated. The residue was chromatographed over a column of silicagel with light petrol:acetone (9:1) as the eluting system to obtain the title compound as a colourless solid (100 mg, 32%) m.p. 108° C.
1 H NMR: δ7.7 (1H, d, J=20 Hz, C=3′H), 7.5 (2H, m), 7.45 (3H, m), 7.1 (1H, t, J=10 Hz, C-12H), 6.4 (1H, d, J=20 Hz, C=2′H), 6.0 (1H, d, J=5.8 Hz, C-14 H), 4.6-4.5 (m), 4.4-4.0 (m), (m, C-3H), 2.5 (2H, dd, C-17 H), 2.35-2.20 (propionyl)
EXAMPLE 9
PREPARATION OF 14-[4′-METHOXYCINNAMOYL]3,19-DIPROPIONYL 8,17-EPOXY ANDROGRAPHOLIDE
Step 1
14-[4-METHOXYCINNAMOYL]8,17-EPOXY ANDROGRAPHOLIDE 3,19-ACETONIDE
Mixed anhydride of 4-methoxy cinnamic acid and ethyl chloro formate was prepared by adding 150 μl of ethyl chloro formate and 250 μl of triethyl amine in succession to a solution of 4-methoxycinnamic acid (250 mg) in 25 ml of dichloromethane at 0° C. under nitrogen atmosphere. The mixture was stirred for 30 minutes at 0° C. To this reaction mixture, a solution of 200 mg of 8,17-epoxy andrographolide 3,19-acetonide in dichloromethane was added dropwise. The resultant mixture was stirred at room temperature for about 12 hours. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was diluted with dichloromethane, washed with saturated NaHCO 3 followed by water and dried over Na 2 SO 4 and concentrated. The residue was chromatographed over a column of silica gel (230-400 mesh) using chloroform:acetone (98:2) as the eluting solvent to obtain the title compound in 89% yield.
Step 2
14-[4-METHOXYCINNAMOYL]8,17-EPOXY ANDROGRAPHOLIDE
The 14-[4-methoxycinnamoyl]ester of 8,17-epoxy andrographolide 3,19-acetonide obtained above (120 mg) was treated with 70% aq. acetic acid to get 110 mg of the 14-[4-methoxycinnamoyl]8,17-epoxy andrographolide in quantitative yield.
Step 3
8,17-EPOXY 14-[4-METHOXYCINNAMOYL]3,19-DIPROPIONYL ANDROGRAPHOLIDE
110 mg of the 14-[4-methoxycinnamoyl]8,17-epoxy andrographolide obtained above was refluxed in 10 ml of propionic anhydride for 15 minutes. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was poured into water and extracted with dichloromethane. The dichloromethane layer was dried and concentrated. The residue was chromatographed over a column of silicagel with light petrol:acetone (9:1) as the eluting system to obtain the title compound as a colourless solid (80 mg, 60%) m.p. 111.8° C.
1 H NMR: δ7.7 (1H, d, J=20 Hz, C-3′H), 7.5 (2H, d, J=10 Hz,) 7.15 (1H, t, J=10 Hz, C-12H), 6.95 (2H, d, J=10 Hz), 6.30 (1H, d, J=20 Hz, C-2′), 6.0 (1H, d, C-14), 4.7-4.5 (m), 4.4-4.0 (m), 3.85 (3H, s) 2.55 (2H, dd, C-17), 2.4-22. (m, Propyl).
EXAMPLE 10
PREPARATION OF 8,17-EPOXY 14-[3′,4′-DIMETHOXYCINNAMOYL]3,19-DIPROPIONYL ANDROGRAPHOLIDE
Step 1
14-[3′4′-DIMETHOXYCINNAMOYL]8,17-EPOXY ANDROGRAPHOLIDE 3,19-ACETONIDE
Mixed anhydride of 3,4-dimethoxy cinnamic acid and ethyl chloro formate was prepared by adding 150 μl of ethyl chloro formate and 250 μl of triethyl amine in succession to a solution of 3,4-dimethoxycinnamic acid (250 mg) in 25 ml of dichloromethane at 0° C. under nitrogen atmosphere. The mixture was stirred for 30 minutes at 0° C. To this reaction mixture 200 mg of 8,17-epoxy andrographolide 3,19-acetonide in dichloromethane was added dropwise. The resultant mixture was stirred at room temperature for about 12 hours. The reaction mixture was monitored by TLC. After completion of the reaction, the reaction mixture was diluted with dichloromethane, washed with saturated NaHCO 3 followed by water and dried over Na 2 SO 4 and concentrated. The residue was chromatographed over a column of silica gel (230-400 mesh) using chloroform:acetone (98:2) as the eluting solvent to obtain the title compound in 44% yield.
Step 2
14-[3,4-DIMETHOXYCINNAMOYL]8,17-EPOXY ANDROGRAPHOLIDE
The 14-[3′,4′-dimethoxycinnamoyl]ester of 8,17-epoxy andrographolide 3,19-acetonide obtained in the step 1 (120 mg) was treated with 70% aq. acetic acid to get 110 mg of the 14-[3,4-dimethoxycinnamoyl]8,17-epoxy andrographolide quantitatively.
Step 3
14-[3′,4′-DIMETHOXYCINNAMOYL]3,19-DIPROPIONYL 8,17-EPOXY ANDROGRAPHOLIDE
110 mg of the 14-[3,4-dimethoxycinnamoyl]8,17-epoxy andrographolide was refluxed in 10 ml of propionic anhydride for 15 minutes. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was poured into water and extracted with dichloromethane. The dichloromethane layer was dried and concentrated. The residue was chromatographed over a column of silicagel with light petrol:acetone (9:1) as the eluting system to yield the title compound as a colourless solid (80 mg, 60%) m.p 128.8° C.
1 H NMR: δ7.7 (1H, d, J=20 Hz, C-3′H), 7.2-7.05 (3H, m, C-6′,9′ & 12), 6.9 (1H, d, J=10 Hz, C-5′), 6.45 (1H, d, J=20 Hz, C-2′), 6.0 (1H, d, J=5.8 Hz, C-14), 4.7-4.5 (m), 4.4-4.0 (m), 3.9 (6H, s) 2.6 (1H, d, C-17), 2.4-2.2 (m, Propyl).
EXAMPLE 11
PREPARATION OF 14-[3′,4′-METHYLENEDIOXYCINNAMOYL]3,19-DIPROPIONYL 8,17-EPOXY ANDROGRAPHOLIDE
Step 1
14-[3′,4′-METHYLENEDIOXY]8,17-EPOXY ANDROGRAPHOLIDE 3,19-ACETONIDE
The mixed anhydride of 3,4-methylenedioxycinnamic acid and ethyl chloro formate was prepared by adding 270 μl of ethyl chloro formate and 500 μl of triethyl amine in succession to a solution of 3,4-methylenedioxy cinnamic acid (475 mg) in 25 ml of dichloromethane at 0° C. under nitrogen atmosphere. The mixture was stirred for 30 minutes at 0° C. To this 400 mg of 8,17-epoxy andrographolide 3,19-acetonide in dichloromethane was added dropwise. The resultant mixture was stirred at room temperature for about 12 hours. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was diluted with dichloromethane, washed with saturated NaHCO 3 followed by water and dried over Na 2 SO 4 and concentrated. The residue was chromatographed over a column of silica gel (230-400 mesh) using chloroform:acetone (98:2) as the eluting solvent to yield 53% of 14-[3′,4′-methylenedioxy]8,17-epoxy andrographolide 3,19-acetonide.
Step 2
14-[3′,4′-METHYLENEDIOXY]8,17-EPOXY ANDROGRAPHOLIDE
The 14-[3′,4′-methylenedioxy cinnamoyl]ester of 8,17-epoxy andrographolide 3,19-acetonide obtained in step 1 above (300 mg) was treated with 70% aq. acetic acid to get 200 mg (71% yield) of the 14-[3′,4′-methylenedioxy cinnamoyl]8,17-epoxy andrographolide.
Step 3
14-[3′,4′-METHYLENEDIOXY CINNAMOYL]3,19-DIPROPIONYL 8,17-EPOXY ANDROGRAPHOLIDE
200 mg of the 14-[3′,4′-methylenedioxy cinnamoyl]8,17-epoxy andrographolide obtained in step 2 above was refluxed in 10 ml of propionic anhydride for 15 minutes. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was poured into water and extracted with dichloromethane. The dichloromethane layer was dried and concentrated. The residue was chromatographed over a column of silicagel with light petrol:acetone (9:1) as the eluting system to yield 14-[3′,4′-methylenedioxy cinnamoyl]3,19-dipropionyl 8,17-epoxyandrographolide as colourless solid (180 mg, 75% ) m.p. 76.7° C.
1 HNMR: 7.65 (1H, d, J=20 Hz, C-3′), 7.15 (1H, t, J=10 Hz, C-12), 7.0 (2H, m C-5′ & 9′), 6.8 (1H, d, C-6′), 6.25 (1H, d, J=20 Hz, C-2′), 6.0 (3H, m, C-14 & C-10′) 4.7-4.5 (m), 4.4-4.0 (m), 2.55 (1H,d, C-17), 2.4-2.2 (m, Propyl).
EXAMPLE 12
PREPARATION OF 14-[N-BOC GLYCINY]8,17-EPOXY ANDROGRAPHOLIDE
Step 1
14-[N-BOC GLYCINYL]8,17-EPOXY ANDROGRAPHOLIDE 3,19-ACETONIDE
14-[N-Boc glycinyl]8,17-epoxy andrographolide 3,19-acetonide was prepared by treating 8,17-epoxy andrographolide 3,19-acetonide with the mixed anhydride of N-Boc glycine and ethyl chloro formate. The mixed anhydride of N-Boc glycine and ethyl chloro formate was prepared by adding 1.75 ml of ethyl chloro formate and 2 ml of triethyl amine in succession to a solution of N-Boc glycine (2 gms) in 25 ml of dichloromethane at −40° C. under nitrogen atmosphere. The mixture was stirred for 15 minutes at −40° C. To this 1 gram of 8,17-epoxy andrographolide 3,19-acetonide in 10 ml dichloromethane and 0.5 ml triethyl amine were added. The resultant mixture was stirred at room temperature for about 3 hours. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was diluted with dichloromethane, washed with saturated NaHCO 3 followed by water and dried over Na 2 SO 4 and concentrated to yield 14-[N-Boc glycinyl]8,17-epoxy andrographolide 3,19-acetonide.
Step 2
14-[N-BOC GLYCINYL]8,17-EPOXY ANDROGRAPHOLIDE
14-[N-Boc glycinyl]8,17-epoxy andrographolide 3,19-acetonide obtained above was treated with 70% aq. acetic acid to yield 600 mg of the 14-[N-Boc glycinyl]ester of 8,17-epoxy andrographolide. The residue was chromatographed over a column of silica gel (230-400 mesh) using chloroform:acetone (9:1) to yield 48% of the pure compound. m.p. 98° C.
1 H NMR: δ7.1 (1H, t, J=10 Hz, C-12), 6.00 (1H, d, J=5.8 Hz, C-14), 5.05 (1H, broad singlet NH), 4.7-4.5 (m), 4.35-4.15 (m), 3.95 (2H), 3.55 (1H, m, C-3H), 3.35 (1H, d, C-19), 2.6 (1H,dd, J=12, 4 Hz, C-17 H).
EXAMPLE 13
PREPARATION OF 14-[N-BOC GLYCINYL]3,19-DIPROPIONYL 8,17-EPOXY ANDROGRAPHOLIDE
300 mg of the 14-[N-Boc glycinyl]8,17-epoxy andrographolide obtained in Example 12 was refluxed in 10 ml of propionic anhydride at 180° C. for 5 minutes. The reaction was monitored by TLC. After completion of the reaction, the reaction mixture was poured into water and extracted with dichloromethane. The dichloromethane layer was dried and concentrated. The residue was chromatographed over a column of silicagel with chloroform:acetone (98:2) as the eluting system to yield the title compound as a colourless solid (160 mg, 44%) m.p 86° C.
1 H NMR: δ7.05 (1H, t, J=10 Hz, C-12), 5.95 (1H, d, J=5.8 Hz, C-14), 5.00 (1H, broad singlet NH), 4.7-4.4 (m), 4.35-4.00 (m), 3.85 (2H), 2.55 (1H,dd, J=12, 4 Hz, C-17 H), 2.35-2.20 (propionyl)
EXAMPLE 14
PREPARATION OF 19-TRITYL 8,17-EPOXY ANDROGRAPHOLIDE
Step 1
19-TRITYL ANDROGRAPHOLIDE
A mixture of andrographolide (5 gms) and trityl chloride (10 gms) in dry pyridine were heated to 80° C. under Nitrogen atmosphere. The heating was continued for 4 hours and the mixture was left at room temperature overnight. The mixture was diluted with solvent ether and washed with water. The organic layer was dried and freed from the solvent. The residue was chromatographed over a column of silicagel with chloroform:acetone (95:5) as the eluent system to obtain 6 gms of 19-trityl andrographolide.
Step 2
19-TRITYL 8,17 EPOXY ANDROGRAPHOLIDE
19-trityl andrographolide (4 gms) obtained in the step 1 was taken in 100 ml of DCM and treated with m-chloro perbenzoic acid. The reaction mixture was stirred at room temperature for 8 hours, concentrated and purified by flash chromatography over a column of silicagel with chloroform:acetone (95:5) to get 19-trityl 8,17 epoxy andrographolide (3.5 gins) m.p: 128° C.
1 H NMR: δ7.5-7.15 (15H, m, Aromatic CH), 6.75 (1H, t, C-13A), 4.95 (1H, d, J=4.8 Hz, C-14H), 4.4-4.1 (m), 3.4-3.1 (m), 2.65 (2H, dd, J=12.4 Hz, C-17H).
EXAMPLE 15
PREPARATION OF 3-ACETYL 8,17-EPOXY ANDROGRAPHOLIDE
Step 1
3-ACETYL 19-TRITYL 8,17-EPOXY ANDROGRAPHOLIDE & 3,14-DIACETYL 19-TRITYL 8,17-EPOXY ANDROGRAPHOLIDE
19-trityl 8,17-epoxy andrographolide (500 mg) obtained in Example 14 was heated in acetic anhydride (15 ml) for 10 minutes at 140° C. The reaction was monitored by TLC. After completion of the reaction, the mixture was poured into cold water and extracted with dichloromethane. The dichloromethane layer was dried over Na 2 SO 4 and freed from the solvent. The residue was shown to contain two compounds. The residue was chromatographed over a column of silica gel (60-120) with chloroform:acetone (99:1) as the eluting system to yield 3-acetyl 19-trityl 8,17-epoxy andrographolide (150 mg) and 3,14-diacetyl 19-trityl 8,17-epoxy andrographolide (165 mg).
Step 2
3-ACETYL 8,17-EPOXY ANDROGRAPHOLIDE
3-Acetyl 19-trityl 8,17-epoxy Andrographolide (100 mg) obtained above was taken in 10 ml of dichloromethane and 5 ml of formic acid was added to the solution. The mixture was stirred for 15 minutes. The mixture was neutralized by passing ammonia and the precipitate of ammonium formate obtained was filtered. The dichloromethane layer was washed with water, dried over Na 2 SO 4 and freed from the solvent. The residue obtained was purified by chromatography over a column of silicagel (60-120) with chloroform:acetone (85:15) to yield the title compound as a colourless solid(50 mg) m.p: 194.3° C.
1 H NMR: 6.8 (1H, t, J=10 Hz, C-12 H), 5.0 (1H, d, J=5.5 Hz, C-14 H), 4.75-4.5 (m)), 4.4-4.0 (m), 3.45 (1H, d, C-19 Hb), 2.8 (2H, dd, J=12, 4 Hz C-17H)
EXAMPLE 16
PREPARATION OF 3,14-DIACETYL 8,17-EPOXY ANDROGRAPHOLIDE
Step 1
ACETYL DERIVATIVE OF 19-TRITYL 8,17-EPOXY ANDROGRAPHOLIDE
19-trityl 8,17-epoxy andrographolide (500 mg) obtained in Example 14 was heated in acetic anhydride (15 ml) for 10 minutes at 140° C. The reaction was monitored by TLC. After completion of the reaction the mixture was poured into cold water and extracted with dichloromethane. The dichloromethane layer was dried over Na 2 SO 4 and freed from the solvent. The residue was chromatographed over a column of silica gel (60-120) with chloroform:acetone (99:1) as the eluting system to yield 3-acetyl 19-trityl 8,17-epoxy andrographolide (150 mg) and 3,14-diacetyl 19-trityl 8,17-epoxy andrographolide (165 mg).
Step 2
3,14-DIACETYL 8,17-EPOXY ANDROGRAPHOLIDE
3,14-diacetyl 19-trityl 8,17-epoxy andrographolide (100 mg) obtained above was taken in 10 ml of dichloromethane and 5 ml of formic acid was added to the solution. The mixture was stirred for 15 minutes. After completion of the reaction, the mixture was diluted with solvent ether, washed with saturated NaHCO 3 solution and water. The ether layer was dried over sodium sulfate and freed from solvent. The residue was chromatographed over a column of silica gel (60-120) with chloroform:acetone (90:10) to yield the title compound as a colourless solid (50 mg) m.p.: 167.9° C.
1 H NMR: 7.1 (1H, t, J=10 Hz, C-12 H), 5.9 (1H, d, J=5.5 Hz, C-14 H), 4.75-4.40 (m,), 4.3-4.0 (m), 3.40 (1H, d, C-19 Hb), 2.6 (2H, dd, J=12, 4 Hz, C-17H), 2.15(3H, s, Acetyl), 2.10 (3H, s, Acetyl).
EXAMPLE 17
PREPARATION OF 14,19-DIACETYL 8,17-EPOXY ANDROGRAPHOLIDE
800 mg of 8,17-epoxy andrographolide obtained in Example 1 was dissolved in a mixture of acetic anhydride (10 ml) and pyridine (520 μl) at −7° C. and stirred for 2 hrs under nitrogen atmosphere. After completion of the reaction it was taken in 50 ml of dichloromethane and washed with saturated copper sulphate solution followed by water. The organic layer was dried over sodium sulphate and freed from the solvent. The residue was chromatographed over a column of silica gel and eluted with light petrol:acetone mixture (80:20 to 75:25) to yield the title compound as colourless solid (200 mg, 20%) m.p: 135.4° C.
1 H NMR: δ7.1 (1H, t, J=10 Hz, C-12 H), 5.85 (1H, d, J=5.8 Hz, C-14 H), 4.6-4.4(m,), 4.4-4.0(m), 3.5-3.2 (1H, m, C-3H) 2.55 (2H, dd, J=12, 4 Hz, C-17H), 2.25(3H, s, acetyl) 2.15 (3H, s, acetyl).
EXAMPLE 18
PREPARATION OF 3,14-DIPROPIONYL 8,17-SPIROEPOXY ANDROGRAPHOLIDE
Step 1
3,14-DIPROPIONYL 19-TRITYL 8,17-EPOXY ANDROGRAPHOLIDE
19-trityl 8,17-epoxy andrographolide (1 gram) obtained in example 14 was refluxed in propionic anhydride (20 ml) at 180° C. for 5 minutes. After completion of the reaction, the reaction mixture was cooled, diluted with water and extracted with dichloromethane. The organic layer was washed with water, dried over Na 2 SO 4 and freed from the solvent. The residue obtained was chromatographed over a column of silicagel with chloroform:acetone (98:2) to yield 3,14-dipropionyl 19-trityl 8,17-epoxy andrographolide.
Step 2
3,14-DIPROPIONYL 8,17-EPOXY ANDROGRAPHOLIDE
3,14-dipropionyl 19-trityl 8,17-epoxy andrographolide obtained above was dissolved in 50% formic acid in dichloromethane and stirred at room temperature for 10 minutes. The mixture was diluted with solvent ether, washed with bicarbonate and water successively. The organic layer was dried over Na 2 SO 4 and the residue obtained after removal of the solvent was chromatographed over a column of silicagel with chloroform:acetone (9:1) to yield the title compound as a colourless solid (200 mg). m.p.: low melting solid.
1 H NMR: 7.1 (1H, t, J=10 Hz, C-12 H), 5.9(1 H, d, J=5.5 Hz, C-14 H), 4.75 (1H, m, 15Ha), 4.4-4.0 (m), 3.45 (1H, d, C-19 Hb), 2.6 (2H, dd, J=C-17H), 2.35 (6H, m, propionyl)
Anti-cancer activity
The compounds prepared in the present invention exhibited good in vitro anti-cancer activity towards various human tumor cell lines.
Each test compound was screened against a battery of cell lines representing eight different types of cancer. In a typical procedure 1×10 4 cells were seeded into each well of 96-well plates in 100 μL volume of RPMI-1640 containing antibiotics and 10% FCS.
The plates were incubated at 37° C. in presence of CO 2 . After 24 h, test compounds were evaluated at five 10 fold dilutions ranging from 100 to 0.01 μM. To each test well 100 μL of test compound solution was added and medium with vehicle was added to control wells and the plates were further incubated. After 48 h of incubation, plates were terminated by Sulforhodamine B method.
The optical density which is proportional to protein mass, is then read by automated spectrophotometric plate readers at a wavelength of 515 nm. Readings were transferred to a microcomputer and mean 50% Growth Inhibition (GI50) and mean Total Growth Inhibition were observed. The compounds of the present invention showed anticancer activity as can be seen from the data given below:
GROWTH INHIBITION (GI 50) [μm]
PANEL/CELL LINES
Example-2
Example-4
Example-7
Example-8
Example-9
Example-10
BREAST:
MCF-7/ADR
5.5
0.8
2.0
0.08
3.0
1.5
CNS:
U251
3.0
0.8
6.0
6.0
3.0
2.0
COLON:
SW-620
1.0
25.0
0.5
2.5
0.6
0.4
LUNG:
H522
20.0
5.5
6.0
20.0
4.8
7.5
MELANOMA:
UACC62
0.55
M14
7.5
1.0
2.5
0.75
0.8
OVARIAN
SKOV-3
4.0
0.45
4.0
10.0
2.0
2.5
PROSTATE:
DU145
20
4.5
5.5
4.0
2.0
2.5
RENAL
A498
0.1
15.0
9.0
3.0
3.0
3.5
TOTAL GROWTH INHIBITION (TGI) [μm]
PANEL/CELL LINES
Example-2
Example-4
Example-7
Example-8
Example-9
Example-10
BREAST:
MCF-7/ADR
40.0
5.0
6.0
4.0
7.5
6.5
CNS:
U251
8.0
10.0
20.0
20.0
6.0
5.5
COLON:
SW-620
7.0
70.0
1.5
5.0
2.0
0.75
LUNG:
H522
70.0
50.0
30.0
60.0
15.0
40.0
MELANOMA:
UACC62
8.0
M14
70.0
4.5
7.5
3.0
9.0
OVARIAN
SKOV-3
7.0
7.5
8.0
40.0
5.0
5.2
PROSTATE:
DU145
60.0
15.0
20.0
10.0
5.5
6.2
RENAL
A498
7.0
75.0
90.0
7.0
7.0
>100
Metabolic Disorders
(a) Efficacy in genetic models
Mutation in colonies of laboratory animals and different sensitivities to dietary regimens have made the development of animal models with non-insulin dependent diabetes and hyperlipidemia associated with obesity and insulin resistance possible. Genetic models such as db/db mice have been developed by the various laboratories for understanding the pathophysiology of disease and testing the efficacy of new antidiabetic compounds (Diabetes, (1983) 32: 830-838; Annu. Rep. Sankyo Res. Lab. (1994). 46: 1-57). The homozygous animals, C57 BL/KsJ-db/db mice developed by Jackson Laboratory, US, are obese, hyperglycemic, hyperinsulinemic and insulin resistant (J. Clin. Invest., (1990) 85: 962-967), whereas heterozygous are lean and normoglycemic. In db/db model, mouse progressively develops insulinopenia with age, a feature commonly observed in late stages of human type II diabetes when blood sugar levels are insufficiently controlled. The state of pancreas and its course vary according to the models. Since this model resembles that of type II diabetes mellitus, the compounds of the present invention were tested for blood sugar and triglycerides lowering activities.
Male C57BL/KsJ-db/db mice of 8 to 14 weeks age, having body weight range of 35 to 60 grams, bred at Dr. Reddy's Research Foundation (DRF) animal house, were used in the experiment. The mice were provided with standard feed (National Institute of Nutrition (NIN), Hyderabad, India) and acidified water, ad libitum. The animals having more than 350 mg/dl blood sugar were used for testing. The number of animals in each group was 4.
Test compounds were suspended in chemophore/DMSO/H 2 O and administered to test group at a dose of 0.1 to 500 mg/kg through oral gavage daily for 6 days. The control group received vehicle (dose 10 ml/kg). On 6th day the blood samples were collected one hour after administration of test compounds/vehicle for assessing the biological activity.
The random blood sugar and triglyceride levels were measured by collecting blood (100 μl) through orbital sinus, using heparinised capillary in tubes containing EDTA which was centrifuged to obtain plasma. The plasma glucose and triglyceride levels were measured spectrometrically, by glucose oxidase and glycerol-3-PO 4 oxidase/peroxidase enzyme (Dr. Reddy's Lab. Diagnostic Division Kits, Hyderabad, India) methods respectively.
The blood sugar and triglycerides lowering activities of the test compound was calculated according to the formula.
Formulae for calculation:
1. Percent reduction in Blood Sugar/triglycerides were calculated according to the formula: Percent reduction ( % ) = [ 1 - TT / OT TC / OC ] × 100
OC=Zero day control group value
OT=Zero day treated group value
TC=Test day control group value
TT=Test day treated group value
Body weight of the animals were measured at the beginning and at the end of the study period.
No adverse effects were observed for any of the mentioned compounds of invention in the above test.
The experimental results from the db/db mice, suggest that the novel compounds of the present invention also possess therapeutic utility as a prophylactic or regular treatment for diabetes, obesity, cardiovascular disorders such as hypertension, hyperlipidaemia and other diseases; as it is known from the literature that such diseases are interrelated to each other.
(b) Plasma triglyceride and body weight reduction in Swiss albino mice Male Swiss albino mice (SAM) were obtained from NIN and housed in DRF animal house. All these animals were maintained under 12 hour light and dark cycle at 25±1° C. Animals were given standard laboratory chow (NIN, Hyderabad, India) and water, ad libitum. SAM of 20-25 g body weight range (Oliver, P., Plancke, M. O., Marzin, D., Clavey, V., Sauzieres, J and Fruchart, J. C. Effects of fenofibrate, gemfibrozil and nicotinic acid on plasma lipoprotein levels in normal and hyperlipidemic mice. Atherosclerosis. 1988. 70: 107-114).
The test compounds were administered orally to Swiss albino mice at 0.3 to 500 mg/kg dose for 6 days. Control mice were treated with vehicle (Chremophore/DMSO/H 2 O; dose 10 ml/kg).
The blood samples were collected in fed state 1 hour after drug administration on 0 and 6 day of treatment. The blood was collected from the retro-orbital sinus through heparinised capillary in EDTA containing tubes. After centrifugation, plasma sample was separated for triglyceride (Wieland, O. Methods of Enzymatic analysis. Bergermeyer, H. O., Ed., 1963. 211-214; Trinder, P. Ann. Clin. Biochem. 1969. 6: 24-27). Measurement of plasma triglyceride was done using commercial kits (Dr. Reddy's Diagnostic Division, Hyderabad, India).
Dose
Percentage reduction
Example
(mg/kg)
TG
Body weight
Example-2
250 mg/kg
19
—
Example-7
250 mg/kg
52
13%
100 mg/kg
42
29%
500 mg/kg
62
—
Example-13
250 mg/kg
31
—
The formula used to measure percent reduction in blood sugar/triglycerides is given above.
Anti HIV Activity
Human CD4+ T cell line PM-1 used in the assay was cultured in RPMI-1640 medium containing 10% Fetal bovine serum, 2 g/L sodium bicarbonate, 100,000 units/L Pencillin-G and 100 mg/L streptomycin. Healthy PM-1 cells were plated on the first day in a 96 well plate at 2×10 6 cells per well. After 24 h HIV-1/MN was added to the culture and incubated for 2 h for infection. Cells were washed twice with PBS to remove the virus in the culture. Different concentrations of DRF compounds ranging from 10 −4 to 10 −8 M were added to the culture and incubated for 96 h. The viability of cells was then assessed by standard MTT assay and the viral antigen P24 levels were estimated by ELSA method. Based on the MTT assay values the P 24 antigen values were corrected.
All the samples were tested in triplicates and the average was used for calculations. AZT was used as standard compound for comparison.
Example
Concentration
Percent Inhibition
Example-2
1 μM
77.25
0.1 μM
75.31
Example-7
1 μM
68.37
Example-13
1 μM
73.94
Lymphocyte Proliferation
Human lymphocycles were isolated from whole blood by using Ficoll Hypaque Plus (Amersham). On day one, 1 million lymphocytes were seeded into each well of 96 well plate in 100 μL volume of RPMI 1640 medium containing 10% FCS and Phytohemagglutitin A at 10 μg/ml concentration. Plates were incubated at 37° C. in CO 2 incubator for 24 h. Test compounds at various concentrations were added to test wells and only medium with vehicle was added to control wells. After 48 h of incubation 0.5 mCi of tritiated thymidine was added to each well. After 24 h of thymidine addition the cells were harvested and the incorporated radioactivity was determined.
Stimulation index (si) was calculated using the formula,
SI
=
A
T
-
A
C
A
C
×
100
A T = Average CPM of treated wells,
A C = Average CPM of control wells.
Example
Concentration
Stimulation Index (SI)
Example-2
1 μM
32
Example-7
1 μM
25
Example-13
1 μM
24
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The present invention relates to novel derivatives of Andrographolide, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, and their pharmaceutically acceptable solvates. The novel derivatives of Andrographolide have the general formula (I)
The andrographolide derivatives represented by general formula (I) are useful for treating cancer, HSV, HIV, psoriasis, restonosis, atherosclerosis, other cardiovascular disorders, and can be used as antiviral, antimalarial, antibacterial, hepatoprotective, and immunomodulating agents and for treatment of other metabolic disorders.
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RELATED APPLICATIONS
This application claims the benefit of U.S. provisional patent application No. 61/377,851 which was filed on Aug. 27, 2010.
BACKGROUND
This section provides background information to facilitate a better understanding of the various aspects of the invention. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
The invention relates in general to wellbore operations and more particular to safety devices and methods to seal, control and monitor subsea oil and gas wells. A blowout preventer is a large, specialized valve used to seal, control and monitor oil and gas wells. Blowout preventers are designed to cope with extreme erratic pressures and uncontrolled flow (formation kick) emanating from a well reservoir during drilling. Kicks can lead to the uncontrolled release of oil and/or gas from a well resulting in a potentially subsea well event known as a blowout. Blowout preventers are critical to the safety of crew, rig (the equipment system used to drill a wellbore) and environment, and to the monitoring and maintenance of well integrity. While blowout preventers are intended to be fail-safe devices, accidents may still occur if the blowout preventer fails to properly operate. For example, during the Apr. 20, 2010, Deepwater Horizon drilling rig explosion, it is believed that the blowout preventers may not have properly operated and/or were not activated in a timely fashion. In addition, due to the failure the wellhead equipment was damaged creating additional obstacles to recovering control of the well.
SUMMARY
According to one or more aspects of the invention, a subsea well safing package for installing on a blowout preventer stack on a subsea well comprises a safing assembly connector interconnecting a lower assembly and an upper safing assembly, the safing assembly connector operable to a disconnected position, wherein the lower safing assembly is adapted to be connected to a blowout preventer stack on a subsea well and the upper safing assembly is adapted to be connected to a marine riser; the lower assembly comprising lower slips to engage a tubular suspended in a bore formed through the lower and the upper safing assemblies; the upper safing package comprising upper slips operable to engage the tubular; and a shear positioned between the upper slips and the lower slips, the shear operable to shear the tubular.
A subsea well safing system according to one or more aspects of the invention comprises a safing assembly comprising a lower safing assembly connected to a blowout preventer stack connected to a subsea well and an upper safing assembly connected to a marine riser; a safing assembly connector interconnecting the lower safing assembly and the upper safing assembly providing a bore therethrough in communication with the marine riser and the well; and an ejector device connected between the upper safing assembly and the lower safing assembly, the ejector device operable to physically separate the upper assembly and connected marine riser from the lower safing assembly.
According to one or more aspects of the invention, a subsea well safing sequence comprises utilizing a safing assembly installed between a blowout preventer stack of a subsea well and a marine riser, the safing assembly comprising a lower safing assembly connected to the blowout preventer stack and an upper safing assembly connected to the marine riser forming a bore between the riser and the blowout preventer stack; securing a tubular suspended in the bore at a position in the lower safing assembly; securing the tubular at a position in the upper safing assembly; shearing the tubular in the bore between the position in the lower safing assembly and the position in the upper safing assembly at which the tubular has been secured; and physically separating the upper safing assembly and the connected marine riser from the lower safing assembly connected to the blowout preventer stack.
The foregoing has outlined some of the features and technical advantages of the invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of various features may be arbitrarily increased or reduced for clarity of discussion.
FIG. 1 a schematic illustration of a subsea safing system according to one or more aspects of the invention utilized in a subsea well drilling system.
FIG. 2 depicts a subsea safing system according to one or more aspects of the invention, wherein the safing sequence has been initiated and the riser and upper safing package are physically and hydraulically disconnected from the lower safing package, the BOP stack, and the well.
FIG. 3 illustrates a subsea well safing assembly according to one or more aspects of the invention in isolation.
FIG. 4A-4B is a flow chart of a subsea well safing sequence according to one or more embodiments of the subsea well safing system.
FIGS. 5-17 are schematic diagrams of safing sequence steps according to one or more embodiments of the subsea well safing system.
FIG. 5A is a sectional view of a vent system according to one or more embodiments of the well safing package shown along the line I-I of FIG. 5 .
FIG. 8A is a sectional view of an embodiment of a deflector device shown along the line I-I of FIG. 8 .
FIG. 8B is a sectional, side view of an embodiment of the impingement device of FIG. 8A in isolation.
FIG. 13A illustrates the riser and upper safing package disconnected and separated from the lower safing package and the wellhead in response to progression of the subsea well safing sequence.
DETAILED DESCRIPTION
It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact.
As used herein, the terms “up” and “down”; “upper” and “lower”; “top” and “bottom”; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements. Commonly, these terms relate to a reference point as the surface from which drilling operations are initiated as being the top point and the total depth of the well being the lowest point, wherein the well (e.g., wellbore, borehole) is vertical, horizontal or slanted relative to the surface.
In this disclosure, “hydraulically coupled” or “hydraulically connected” and similar terms, may be used to describe bodies that are connected in such a way that fluid pressure may be transmitted between and among the connected items. The term “in fluid communication” is used to describe bodies that are connected in such a way that fluid can flow between and among the connected items. It is noted that hydraulically coupled may include certain arrangements where fluid may not flow between the items, but the fluid pressure may nonetheless be transmitted. Thus, fluid communication is a subset of hydraulically coupled.
A subsea well safing system is disclosed to provide a means for mitigating the environmental and economic damage that can result from the loss of control of a well, such as occurred in the Macondo well being drilled from the Deepwater Horizon on 20 Apr. 2010. According to one or more aspects of the invention, the subsea well safing system provides a mechanism to separate the riser from the blowout preventer stack and the well in a manner intended to limit the physical damage to the well drilling system and to enhance the potential for successfully reconnecting to the well, for example via BOP stack, to regain control of the well.
FIG. 1 is a schematic illustration of a subsea well safing system, generally denoted by the numeral 10 , being utilized in a subsea well drilling system 12 . In the depicted embodiment drilling system 12 includes a BOP stack 14 which is landed on a subsea wellhead 16 of a well 18 (i.e., wellbore) penetrating seafloor 20 . BOP stack 14 conventionally includes a lower marine riser package (“LMRP”) 22 and blowout preventers (“BOP”) 24 . The depicted BOP stack 14 also includes subsea test valves (“SSTV”) 26 . As will be understood by those skilled in the art with benefit of this disclosure, BOP stack 14 is not limited to the devices depicted.
Subsea well safing system 10 comprises safing package, or assembly, referred to herein as a catastrophic safing package (“CSP”) 28 that is landed on BOP system 14 and operationally connects a riser 30 extending from platform 31 (e.g., vessel, rig, ship, etc.) to BOP stack 14 and thus well 18 . CSP 28 comprises an upper CSP 32 and a lower CSP 34 that are adapted to separate from one another in response to initiation of a safing sequence thereby disconnecting riser 30 from the BOP stack 14 and well 18 , for example as illustrated in FIG. 2 . The safing sequence is initiated in response to parameters indicating the occurrence of a failure in well 18 with the potential of leading to a blowout of the well. According to one or more embodiments of the invention, subsea well safing system 10 may automatically initiate the safing sequence in response to the correspondence of monitored parameters to selected safing triggers. According to one or more embodiments of the invention CSP 28 may include an accumulator 29 , see FIGS. 3 and 7 , hydraulically connected to wellhead 16 to operate the wellhead connector lock as further described below. In the embodiment of depicted in FIG. 7 , wellhead accumulator 29 is depicted as a standalone, accumulator located proximate to seafloor 20 and wellhead 16 .
Wellhead 16 is a termination of the wellbore at the seafloor and generally has the necessary components (e.g., connectors, locks, etc.) to connect components such as BOPs 24 , valves (e.g., test valves, production trees, etc.) to the wellbore. The wellhead also incorporates the necessary components for hanging casing, production tubing, and subsurface flow-control and production devices in the wellbore.
BOP stack 14 commonly includes a set of two or more BOPs 24 utilized to ensure pressure control of well 18 . A typical stack might consist of one to six ram-type preventers and, optionally, one or two annular-type preventers. A typical stack configuration has the ram preventers on the bottom and the annular preventers at the top. The configuration of the stack preventers is optimized to provide maximum pressure integrity, safety and flexibility in the event of a well control incident. For example, one set of rams may be fitted to close on the drillpipe, blind rams to close on the open hole, and another set of shear rams to cut and hang-off the drillpipe. It is also common to have an annular preventer at the top of the stack to close over a wide range of tubular (e.g., drillpipe) sizes and the open hole. BOP stack 14 also includes various spools, adapters, and piping ports to permit circulation of wellbore fluids under pressure in the event of a well control incident.
LMRP 22 and BOP stack 14 are coupled together by a wellbore connector that is engaged with a corresponding mandrel on the upper end of BOP stack 24 . LMRP 22 typically provides the interface (i.e., connection) of the BOPs 24 and the bottom end 30 a of marine riser 30 via a riser connector 36 (i.e., riser adapter). Riser connector 36 commonly comprises a riser adapter for connecting the lowest end 30 a of riser 30 (e.g., bolts, welding, hydraulic connector) and a flex joint that provides for a range of angular movement of riser 30 (e.g., 10 degrees) relative to BOP stack 14 , for example to compensate for vessel 31 offset and current effects on along the length of riser 30 . Riser connector 36 may further comprise one or more ports for connecting fluid (i.e., hydraulic) and electrical conductors, i.e., communication umbilical, which may extend along (exterior or interior) riser 30 from the drilling platform located at surface 5 to subsea drilling system 12 . For example, it is common for a hydraulic choke line 44 and a hydraulic kill line 46 to extend from the surface for connection to BOP stack 14 .
Riser 30 is a tubular string that extends from the drilling platform 31 down to well 18 . The riser is in effect an extension of the wellbore extending through the water column to drilling vessel 31 . The riser diameter is large enough to allow for drillpipe, casing strings, logging tools and the like to pass through. For example, in FIGS. 1 and 2 , a tubular 38 (e.g., drillpipe) is illustrated deployed from drilling platform 31 into riser 30 . Drilling mud and drill cuttings can be returned to surface 5 through riser 30 . Communication umbilical (e.g., hydraulic, electric, optic, etc.) can be deployed exterior to or through riser 30 to CSP 28 and BOP stack 14 . A remote operated vehicle (“ROV”) 124 is depicted in FIG. 2 and may be utilized for various tasks.
Refer now to FIG. 3 which illustrates a subsea well safing package 28 according to one or more aspects of the invention in isolation. CSP 28 depicted in FIG. 3 is further described with reference to FIGS. 1 and 2 . In the depicted embodiment, CSP 28 comprises upper CSP 32 and lower CSP 34 . Upper CSP 32 comprises a riser connector 42 which may include a riser flange connection 42 a , and a riser adapter 42 b which may provide for connection of communication umbilicals and extension of the communication umbilicals to various CSP 28 devices and/or BOP stack 14 devices. For example, a choke line 44 and a kill line 46 are depicted extending from the surface with riser 30 and extending through riser adapter 42 b for connection to the choke and kill lines of BOP stack 14 . CSP 28 comprises a choke stab 44 a and a kill line stab 46 a for interconnecting the upper portion of choke line 44 and kill line 46 with the lower portion of choke line 44 and kill line 46 . As will be further described below with reference to safing sequence 86 , stabs 44 a , 46 a also provide for disconnecting from the stab and kill lines during a safing operations; and during subsequent recovery and reentry operations reconnecting to the choke and kill lines via stabs 44 a , 46 a . In some embodiments, riser connector 42 may also comprise a flex joint.
CSP 28 comprises an internal longitudinal bore 40 , depicted in FIG. 3 by the dashed line through lower CSP 34 , for passing tubular 38 . Annulus 41 is formed between the outside diameter of tubular 38 and the diameter of bore 40 .
Upper CSP 32 further comprises a slips 48 (i.e., safety slips) adapted to close on tubular 38 . Slips 48 are actuated in the depicted embodiment by hydraulic pressure from an accumulator 50 . In the depicted embodiment, CSP 28 comprises a plurality of hydraulic accumulators 50 which may be interconnected in pods, such as upper accumulator pod 52 . As will be understood by those skilled in the art with benefit of the present disclosure, accumulators 50 may be provided in various configurations. In the depicted embodiment, accumulators 50 are hydraulically charged and do not require connection to a hydraulic source at the surface. It will also be recognized by those skilled in the art that hydraulic pressure may be provided from the surface. In this embodiment, accumulators 50 located in the upper accumulator pod 52 are at least hydraulic connected to slips 48 . In one or more embodiments of the invention, the pressure in accumulators 50 are monitored and accumulators 50 may be actuated in sequence and as needed to ensure that adequate hydraulic pressure is available and provided for actuation of CSP devices such as slips 48 .
Lower CSP 34 comprises a connector 54 to connect to BOP stack 14 , for example, via riser connector 36 , rams 56 (e.g., blind rams), high energy shears 58 , lower slips 60 (e.g., bi-directional slips), and a vent system 64 (e.g., valve manifold). Vent system 64 comprises one or more valves 66 . In this embodiment, vent system 64 comprise vent valves (e.g., ball valves) 66 a , choke valves 66 b , and one or more connection mandrels 68 . Valves 66 b can be utilized to control fluid flow through connection mandrels 68 . For example, a recovery riser 126 is depicted connected to one of mandrels 68 for flowing effluent from the well and/or circulating a kill fluid (e.g., drilling mud) into the well as further described below. Vent system 64 is further described below with reference to FIGS. 5 and 5A .
In the depicted embodiment, lower CSP 34 further comprises a deflector device 70 (e.g., impingement device, shutter ram) disposed above vent system 64 and below lower slips 60 , shears 58 , and blind rams 56 . Lower CSP 34 includes a plurality of hydraulic accumulators 50 that are arranged and connected in one or more lower hydraulic pods 62 for operations of various devices of CSP 28 . As will be further described below, CSP 28 , in particular lower CSP 34 , may include methanol, or other chemical, source 76 operationally connected for injecting into lower CSP 34 , for example to prevent hydrate formation.
Upper CSP 32 and lower CSP 34 are detachably connected to one another by a connector 72 . CSP connector 72 is depicted in the illustrated embodiments as a collet connector, comprising a first connector portion 72 a and a second mandrel connector portion 72 b which are illustrated for example in FIG. 13A . An ejector device 74 (e.g., ejector bollards) is operationally connected between upper CSP 32 and lower CSP 34 to separate upper CSP 32 and riser 30 from lower CSP 34 and BOP stack 14 after connector 72 has been actuated to the unlocked position. CSP 28 also includes a plurality of sensors 84 which can sense various parameters, such as and without limitation, temperature, pressure, strain (tensile, compression, torque), vibration, and fluid flow rate. Sensors 84 further includes, without limitation, erosion sensors, position sensors, and accelerometers and the like. Sensors 84 can be in communication with one or more control and monitoring systems, for example as further described below, forming a limit state sensor package.
According to one or more embodiments of the invention, CSP 28 comprises a control system 78 which may be located subsea, for example at CSP 28 or at a remote location such as at the surface. Control system 78 may comprise one or more controllers which are located at different locations. For example, in at least one embodiment, control system 78 comprise an upper controller 80 (e.g., upper command and control data bus) and a lower controller 82 (e.g., lower command and controller bus). Control system 78 may be connected via conductors (e.g., wire, cable, optic fibers, hydraulic lines) and/or wirelessly (e.g., acoustic transmission) to various subsea devices and to surface (i.e., drilling platform 31 ) control systems.
With reference to the embodiments depicted in FIGS. 3 to 17 , control system 78 includes upper controller 80 and a lower controller 82 . Each of upper and lower controllers 80 , 82 may comprise a collection of real-time computer circuitry, field programmable gate arrays (FPGA), I/O modules, power circuitry, power storage circuitry, software, and communications circuitry. One or both of upper and lower controller 80 , 82 may comprise control valves.
According to at least one embodiment, one of the controllers, for example lower controller 82 , serves as the primary controller and provides command and control sequencing to various subsystems of safing package 28 and/or communicates commands from a regulatory authority for example located at the surface. The primary controller, e.g., lower controller 82 , contains communications functions, and health and status parameters (e.g., riser strain, riser pressure, riser temperature, wellhead pressure, wellhead temperature, etc.). One or more of the controllers may have black-box capability (e.g., a continuous-write storage device that does not require power for data recovery).
Upper controller 80 is described herein as operationally connected with a plurality of sensors 84 positioned throughout CSP 28 and may include sensors connected to other portions of the drilling system, including along riser 30 , at wellhead 16 , and in well 18 . Upper controller 80 , using data communicated from sensors 84 , continuously monitors limit state conditions of drilling system 12 . According to one or more embodiments, upper controller 80 , may be programmed and reprogrammed to adapt to the personality of the well system based on data sensed during operations. If a defined limit state is exceeded an activation signal (e.g., alarm) can be transmitted to the surface and/or lower controller 82 . A safing sequence may be initiated automatically by control system 78 and/or manually in response to the activation signal.
With reference to FIGS. 4A and 4B , a safing sequence 86 according to one or more embodiments of subsea well safing system 10 is disclosed. In sequence step 88 , the safing sequence is initiated in response to monitoring the limit state sensor 84 package by upper controller 80 . In sequence step 90 , pressure is vented from CSP 28 by opening a valve 66 a in vent system 64 , see, e.g., FIGS. 1 , 3 , 5 and 5 A. In sequence step 92 , the choke and kill lines are closed to prevent combustibles from flowing up from the well and to the surface through the kill and choke lines, see, e.g., FIGS. 1 , 3 and 6 . In sequence step 94 , the wellhead 16 connector lock is pressurized to prevent accidental ejection of BOP stack 14 from wellhead 16 , see, e.g., FIGS. 3 and 7 . In sequence step 96 , fluid flowing up from the well is diverted, e.g., partially diverted, to the open vents to prevent erosion of CSP elements such as the slips 48 , 60 , see, e.g., FIGS. 1 , 3 , 8 , 8 A and 8 B. For example, fluid flow may be diverted by operating a deflector device 70 to a closed position. In sequence step 98 , tubular 38 is secured in lower CSP 34 by closing lower slips 60 (e.g., bi-directional slips), see, e.g., FIGS. 1 , 3 and 9 . In sequence step 100 , tubular 38 is secured in upper CSP 32 by closing upper slips 48 (e.g., safety slips), see, e.g., FIGS. 1 , 3 and 10 . In sequence step 102 , tubular 38 is sheared in lower CSP 34 by activating shears 58 , see, e.g., FIGS. 1 , 3 and 11 . In sequence step 104 , upper CSP 32 and lower CSP 34 are disconnected from one another by operating CSP connector 72 to a disconnected position, see, e.g., FIGS. 1 , 3 , 12 and 13 A. In sequence step 106 , riser 30 and upper CSP 32 are separated (e.g., ejected) from lower CSP 34 and BOP stack 14 by activating ejector device 74 (i.e., ejector bollards), see, e.g., FIGS. 1-3 , 13 , and 13 A. In sequence step 108 , (see, e.g., FIGS. 1-3 and 14 ) blind rams 56 are closed to shut-off fluid flow from BOP stack 14 through bore 40 (see FIG. 3 ) and escaping to the environment. In sequence step 110 , treating hydrate formation in lower CSP 34 by injecting methanol, see, e.g., FIGS. 1-3 and 15 . In sequence step 112 , closing the vents 66 a opened in vent system 64 in sequence step 90 , see, e.g., FIGS. 1-3 and 16 . In sequence step 114 , performing a formation stability test, see, e.g., FIGS. 1-3 and 17 .
FIG. 5 is a schematic diagram of sequence step 90 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 and 3 . In response to initiating safing sequence 86 , one or more vent valves 66 a of vent system 64 are opened. Valves 66 a are opened to reduce the flow of fluid through the annulus 41 between tubular 38 and the CSP 28 walls forming bore 40 through CSP 28 (see FIG. 3 , the dashed lines in lower CSP 34 ) and lowering the backpressure on lower slips 60 . The open and closed position of vent valves 66 a can be verified by a control signal from each valve position sensor 84 . An accumulator 50 located in the assigned accumulator pod 62 is activated to provide hydraulic power to the valve actuators 116 of controller 82 . Lower controller 82 continuously monitors the accumulator pod 62 pressure and activates additional accumulators 50 as may be required to maintain working pressure. With reference to FIGS. 5-17 , the active device (e.g., accumulators, valves, slips, shears) of the depicted sequence step are emphasized by hatching.
FIG. 5A is a sectional view of an embodiment of vent system 64 shown along the line I-I of FIG. 5 . FIG. 5A depicts two vent valves 66 a on each side of vent system 64 , which are depicted in the closed position. Valves 66 b are positioned to control flow through connection mandrels 68 . In the depicted embodiment, the sensor 84 located proximate to the connection mandrel 84 is an accelerometer.
FIG. 6 is a schematic diagram of sequence step 92 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 and 3 . In sequence step 92 , valves 118 positioned in each of choke line 44 and kill line 46 are actuated from the open to the closed position to prevent combustibles from flowing up the choke line 44 and the kill line 46 .
FIG. 7 is a schematic diagram of sequence step 94 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 and 3 . Controller 82 initiates the pressurization of wellhead connector lock 120 to prevent the accidental ejection of BOP stack 14 from wellhead 16 due to the high back pressure encountered in subsequent sequence steps, e.g., when deflector device 70 is closed, slips 48 , 60 are closed; and due to the loss of hydraulic pressure to wellhead connector lock 120 when riser 30 is disconnected from BOP stack 14 disconnecting any hydraulic sources extending along riser 30 to CSP 28 .
FIG. 8 is a schematic diagram of sequence step 96 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 , 3 , 8 A and 8 B. In sequence step 96 , controller 82 actuates deflector device 70 , described in the embodiments of FIG. 8 , 8 A and 8 B as shutter ram 70 , to a closed position (see FIG. 8A ) in response to applying hydraulic pressure in the embodiment of FIG. 8 from a hydraulic accumulator 50 of lower accumulator pod 62 . In the closed position, deflector device 70 diverts fluid flow from passing through annulus 41 of CSP 28 to vent system 64 and open vent valves 66 a . The closed shutter ram 70 , depicted in FIG. 8A , protects CSP 28 from the high flow rates and entrained solids that are encountered thereby limiting erosion of devices of CSP 28 , such as upper safety slips 48 and lower slips 60 . Shutter ram 70 may be provided in various manners and configurations. Referring to FIG. 8A , tubular 38 is depicted substantially centered within bore 40 of shutter ram 70 which is coaxial with bore 40 of CSP 28 by rams 70 A, 70 B, and 70 C. According to at least one embodiment, closure of rams 70 A, 70 B, 70 C does not seal annulus 41 . In the embodiment as depicted in FIG. 8B , each of rams 70 A, 70 B and 70 C comprises stacked and spaced apart plates 71 which interleave portions of the plates 71 of the adjacent rams.
FIG. 9 is a schematic diagram of sequence step 98 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 and 3 . In sequence step 98 , controller 82 actuates lower slips 60 (e.g., bi-directional slips) securing tubular 38 within lower CSP 34 in preparation for sequence step 102 . In some embodiments, lower slips 60 may comprise deflector armor to divert fluid flow toward vent system 64 instead of, or in addition to, shutter ram 70 described and disclosed with reference to sequence step 96 and FIGS. 8 , 8 A, and 8 B.
FIG. 10 is a schematic diagram of sequence step 100 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 and 3 . In sequence step 100 , upper slips 48 are actuated to engage tubular 38 within upper CSP 32 . In this embodiment, sequence step 100 is actuated by upper controller 80 . As with other sequence steps, the controller monitors the pressure status of accumulators 50 and if a low pressure is detected, a subsequent accumulator in a pod is activated to actuate the sequence step device (i.e., slips 48 in sequence step 100 ).
FIG. 11 is a schematic diagram of sequence step 102 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 and 3 . After tubular 38 is engaged and secured respectively in upper CSP 32 (i.e., by slips 48 ) and lower CSP 34 (i.e., slips 60 ), lower controller 82 actuates shears 58 thereby shearing tubular 38 between upper slips 48 and lower slips 60 .
FIG. 12 is a schematic diagram of sequence step 104 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 , 2 , 3 and 13 A. In sequence step 104 , CSP connector 72 is actuated to the open, or disconnected, position permitting separation of upper CSP 32 from lower CSP 34 in sequence step 106 . In this embodiment, CSP connector 72 is actuated via upper controller 80 and hydraulic accumulators 50 located in upper accumulator pod 52 . In the depicted embodiment, CSP connector 72 is a collet comprising a first connector portion 72 a and a second connector portion 72 b , depicted for example in FIG. 13A . Second connector portion 72 b is disposed with lower CSP 34 and comprises a mandrel, identified individually by the numeral 72 c (see, FIGS. 13A , 14 - 17 ). The mandrel 72 c provides a mechanism for reconnecting, for example with a riser, for re-entry into well 18 .
FIG. 13 is a schematic diagram of sequence step 106 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1-3 and 13 A. In sequence step 106 , ejector devices 74 (i.e., ejector bollards) are actuated to physically separate upper CSP 32 and riser 30 from lower CSP 34 as depicted in FIGS. 2 and 13A . For example, ejector devices 74 may include piston rods 74 a which extend to push the upper CSP 32 away from lower CSP 34 in the depicted embodiment. FIGS. 2 , 13 A, and 14 - 17 illustrate piston rod 74 a in an extended position. In the embodiment of FIG. 13 , actuation of ejector devices 74 is provided by upper controller 80 and accumulator(s) 50 located in upper accumulator pod 52 .
Typically, riser 30 will be in tension which will assist in pulling the disconnected upper CSP 32 vertically away from lower CSP 34 . In addition, the water currents and deflection in riser 30 (e.g., offset from platform 31 ) will assist in moving riser 30 and separated upper CSP 32 laterally away from lower CSP 34 and the well. Choke line 44 and kill line 46 are disconnected respectively at choke stab 44 a and kill stab 46 a ( FIG. 3 ). Stabs 44 a and 46 b provide a means for reconnection to surface sources during recovery operations.
In the depicted embodiments, ejector device 74 is attached to lower CSP 34 and piston rods 74 a push against a portion of upper CSP 32 , for example a portion of the frame 122 of upper CSP 32 shown generally in FIG. 13 . It will be understood by those skilled in the art with benefit of this disclosure that ejector device 74 may be arranged in different configurations without departing from the scope of the invention. For example, ejector device 74 may be reversed so as to be attached with upper CSP 32 wherein piston rod 74 a acts against lower CSP 34 .
FIG. 14 is a schematic diagram of sequence step 108 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 , 2 and 3 . In sequence step 108 , blind rams 56 are actuated to the closed position sealing bore 40 (see FIGS. 3 and 8A , 8 B) to block any fluid that may be flowing up from well 18 through BOP stack 14 . In the depicted embodiment, actuation of blind rams 56 is provided by lower controller 82 and accumulator(s) 50 located in lower accumulator pod(s) 62 .
FIG. 15 is a schematic diagram of sequence step 110 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 , 2 and 3 . In sequence step 110 , methanol 76 may be injected into lower CSP 34 to prevent hydrate formation CSP 28 , in particular in the vents (e.g., vent valves 66 a ) of vent system 64 . In the depicted embodiment, the injection of methanol 76 is provided by lower controller 82 and may be powered by accumulator(s) 50 located in lower accumulator pod(s) 62 .
FIG. 16 is a schematic diagram of sequence step 112 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1 , 2 and 3 . In sequence step 112 , lower controller 82 actuates hydraulic power (e.g., accumulator 50 ) to actuate the open vent valves 66 a from the open to the closed position.
FIG. 17 is a schematic diagram of sequence step 114 , according to one or more embodiments of subsea well safing system 10 which is described with further reference to FIGS. 1-3 . Subsequent to closing vent valves 66 a in sequence step 112 , lower controller 82 can initiate and perform a formation stability test for example by monitoring wellhead temperature and pressure via one or more sensors 84 .
If stable formation conditions are indicated, safing system 10 may be placed in a standby condition until recovery operations can be initiated and completed. If unstable formation conditions are indicated, vent valves 66 a may be opened to relieve pressure in an effort to prevent a subsurface blowout of well 18 , which will result in loss of the well and require more difficult and time consuming processes to plug well 18 . With effluent venting to the environment, a recovery riser 126 extending, for example from a vessel at surface 5 , may be connected to connection mandrel 68 of vent system 64 as depicted in FIG. 3 . ROV 124 ( FIG. 2 ) may be utilized to connect flexible riser 126 . A valve, such as valve 68 b , may be operated to the open position permitting flow of effluent through mandrel 68 of vent system 64 into riser 126 and to the surface; and the open vent valves 66 a are operated to the closed position, thus providing a means to limit environmental damage until control of well 18 can be recovered.
According to one embodiment, a method of recovery of well 18 comprises closing in well 18 via lower CSP 34 and/or venting effluent from well 18 through vent system 64 and a recovery riser 126 to the surface. A riser 30 and choke line 44 and/or kill line 46 hydraulics are extended from the surface to lower CSP 34 . Choke and kill lines 44 , 46 can be connected to BOP stack 14 and well 18 via choke stab 44 a and kill stab 46 a which are located on lower CSP 34 which is still connected to well 18 . Riser 30 in some circumstances may be connected to connector mandrel 72 b of CSP connector 72 to reestablish hydraulic communication with well 18 through BOP stack 14 . Depending on the status of BOP stack 14 and formation stability, drilling mud may be circulated down one of riser 30 , kill line 46 , choke line 44 , and/or flexible riser 126 to kill well 18 .
According to one or more aspects of the invention, a subsea well safing package for installing on a blowout preventer stack on a subsea well comprises a safing assembly connector interconnecting a lower safing assembly and an upper safing assembly, the safing assembly connector operable to a disconnected position, wherein the lower safing assembly is adapted to be connected to a blowout preventer stack on a subsea well and the upper safing assembly is adapted to be connected to a marine riser; the lower assembly comprising lower slips to engage a tubular suspended in a bore formed through the lower and the upper safing assemblies; the upper safing assembly comprising upper slips operable to engage the tubular; and a shear positioned between the upper slips and the lower slips, the shear operable to shear the tubular.
According to one or more aspects of the invention a subsea well safing package is provided for installing on a blowout preventer stack on a subsea well comprises a safing assembly connector interconnecting a lower safing assembly and an upper safing assembly, the safing assembly connector operable to a disconnected position, wherein the lower safing assembly is adapted to be connected to a blowout preventer stack on a subsea well and the upper safing assembly is adapted to be connected to a marine riser; the lower assembly comprising lower slips to engage a tubular suspended in a bore formed through the lower and the upper safing assemblies; the upper safing assembly comprising upper slips operable to engage the tubular; a shear positioned between the upper slips and the lower slips, the shear operable to shear the tubular; and an ejector device connected between lower safing assembly and the upper safing assembly, the ejector device operable to physically separate the upper safing assembly from the lower safing assembly.
The package may include a vent carried by the lower safing assembly, the vent operable between an open and a closed position. In at least one embodiment the package further includes a vent carried by the lower safing assembly and positioned below the lower slip when connected to the well, wherein the vent is operable between an open and a closed position.
According to one or more embodiments of the invention, the ejector device includes an extendable piston rod. The piston rod may be extendable in response to the application of hydraulic pressure.
According to one or more embodiments of the invention, the safing package comprises a hydraulic accumulator disposed with the safing assembly and in hydraulic communication with the lower slips. In some embodiments, a plurality of hydraulic accumulators are arranged in an upper accumulator pod, wherein the upper accumulator pod is in hydraulic communication with the upper slips. According to at least one embodiment the shear is in hydraulic communication with at least one of a lower hydraulic accumulator pod and an upper hydraulic accumulator pod. Similarly, the ejector device is in hydraulic communication with at least one of a lower hydraulic accumulator pod and an upper hydraulic accumulator pod in some embodiments.
According to one or more embodiments, a vent is carried by the lower safing assembly and positioned below the lower slip when connected to the well, wherein the vent is operable between an open and a closed position; and a deflector device is positioned between the lower slips and the vent, wherein the deflector device is operable to a closed position to divert fluid flow toward the vent. In some embodiments, the deflector device does not seal against the tubular suspended in the lower safing assembly when in the closed position.
A subsea well safing system according to one or more aspects of the invention comprises a safing assembly comprising a lower safing assembly connected to a blowout preventer stack connected to a subsea well and an upper safing assembly connected to a marine riser; a safing assembly connector interconnecting the lower safing assembly and the upper safing assembly providing a bore therethrough in communication with the marine riser and the well; and an ejector device connected between the upper safing assembly and the lower safing assembly, the ejector device operable to physically separate the upper assembly and connected marine riser from the lower safing assembly.
The safing assembly can further comprise, for example, lower slips operable to engage a tubular suspended in the bore of the lower safing assembly; upper slips operable to engage the tubular suspend in the bore of the upper safing assembly; a shear located between the lower slips and the upper slips operable to shear the tubular; and a vent in communication with the bore, the vent operable between a closed position and an open position. In some embodiments, the safing system further comprises a deflector device located in the lower safing assembly between the lower slips and the vent, the deflector device operable to a closed position to divert fluid flow toward the vent.
According to one or more aspects of the invention, a subsea well safing sequence comprises utilizing a safing assembly installed between a blowout preventer stack of a subsea well and a marine riser, the safing assembly comprising a lower safing assembly connected to the blowout preventer stack and an upper safing assembly connected to the marine riser forming a bore between the riser and the blowout preventer stack; securing a tubular suspended in the bore at a position in the lower safing assembly; securing the tubular at a position in the upper safing assembly; shearing the tubular in the bore between the position in the lower safing assembly and the position in the upper safing assembly at which the tubular has been secured; and physically separating the upper safing assembly and the connected marine riser from the lower safing assembly connected to the blowout preventer stack.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the disclosure. Those skilled in the art should appreciate that they may readily use the disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the disclosure. The scope of the invention should be determined only by the language of the claims that follow. The term “comprising” within the claims is intended to mean “including at least” such that the recited listing of elements in a claim are an open group. The terms “a,” “an” and other singular terms are intended to include the plural forms thereof unless specifically excluded.
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A subsea well safing method and apparatus adapted to secure a subsea well in the event of a perceived blowout in a manner to mitigate the environmental damage and the physical damage to the subsea wellhead equipment to promote the ability to reconnect and recover control of the well. The safing assembly is adapted to connect the marine riser to the BOP stack. Pursuant to a safing sequence, the well tubular is secured in the upper and lower safing assemblies and the tubular is then sheared between the locations at which it has been secured. Subsequently, an ejection device is actuated to physically separate the upper safing assembly and connected marine riser from the lower safing assembly that is connected to the BOP stack.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority in U.S. Provisional Patent Application No. 62/289,544, filed Feb. 1, 2016, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to a functional ornamentation and method for use and manufacture thereof, and more specifically to a twisted metal ornamentation with functional features for fishing lures, jewelry, and general decoration.
[0004] 2. Description of the Related Art
[0005] The prior art is manufactured typically by taking a square piece of metal, twisting the metal the appropriate amount of rotations, and then using a grinder and/or cutting tools to form the final shape of the functional ornamentation. This is a tedious and labor intensive process and requires a later step of painting the ornamentation, which is difficult once the ornamentation has been bent.
[0006] When used as part of a fishing lure, the prior art devices are limited to a single type of action, whether that is top of the water fishing, deep water fishing, or vertical jigging. Those intended for deep water fishing typically are confined to travel along a designed arc path, which is not ideal for fishing due to the unnatural path through the water.
[0007] The ornamentation of the prior art has similar issues when used in other fields, such as hanging ornamentation in chandeliers, wind chimes, or jewelry. The cost prohibitive nature of the manufacture of those elements only increases with the size and scale of the ornamentation. What is needed is a method of manufacturing a unique ornamentation device that not only offers superior functionality as a fishing lure, but has multitudes of other uses as well due to its unique shape.
[0008] Heretofore there has not been available a system or method for functional ornamentation with the advantages and features of the present invention.
BRIEF SUMMARY OF THE INVENTION
[0009] The present invention generally provides a functional ornamentation manufactured from a stamped metal plate which is twisted by a specified number of degrees to result in a shape that allows for unique reactions to flowing fluids such as air and water. Due to the shape and twist of the device, the device will spin along with the flowing fluid or when pulled through that fluid, such that it retains a straight trajectory. In a preferred embodiment, such as part of a fishing lure, the ornamentation is connected to a ball bearing swivel which allows for near frictionless rotation. The lure can be used at the surface of the water, in deep water, or in a vertical jig orientation (e.g. ice fishing) with identical results. The lure when drawn through the water travels in a straight path, rather than an arced path of the prior art. This results in a more natural travel path producing greater flash and rotation for attacking fish. Elements may be affixed to the ornamentation or the fishing hook which knock against the ornamentation or spin out from the ornamentation for additional attraction of fish, including additional flash or noise.
[0010] The ornamentation may be used for multiple other purposes, including earrings and other jewelry, chandeliers, and wind chimes. A hanging decoration including a fan for moving air allows for multiple hanging elements of the present invention to spin freely with perfect vertical rotation. When design elements are painted, printed, or cut out from the ornamentation, those design elements produce unique images while the ornamentation is spinning freely. Painted or printed images of figures produce an optical illusion of a three-dimensional figure in the air as the ornamentation spins.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The drawings constitute a part of this specification and include exemplary embodiments of the present invention illustrating various objects and features thereof.
[0012] FIG. 1 is a three dimensional view of a first embodiment of the present invention.
[0013] FIG. 2 is a front elevational view of an embodiment of the present invention in an un-twisted orientation.
[0014] FIG. 3 is a front elevational view of a prior art embodiment thereof.
[0015] FIG. 4 is a front elevational view of the embodiment of FIG. 1 .
[0016] FIG. 5 is a side elevational view thereof.
[0017] FIG. 6 is a front elevational view of a second embodiment of the present invention.
[0018] FIG. 7 is a side elevational view thereof.
[0019] FIG. 8 is a front elevational view of a third embodiment of the present invention.
[0020] FIG. 9 is a side elevational view thereof.
[0021] FIG. 10 is a front elevational view of the embodiment of FIG. 4 shown including a fishing hook.
[0022] FIG. 11 is a front elevational view of the embodiment of FIG. 6 shown including a fishing hook.
[0023] FIG. 12 is a front elevational view of the embodiment of FIG. 4 shown including a pair of tail elements attached by a chain.
[0024] FIG. 13 is a front elevational view of a fourth embodiment of the present invention in an un-twisted orientation.
[0025] FIG. 14 is a front elevational view thereof in a twisted orientation.
[0026] FIG. 15A is a side elevational view thereof.
[0027] FIG. 15B is a side elevational view thereof, showing connection with an external element.
[0028] FIG. 16 is a three dimensional isometric view thereof.
[0029] FIG. 17 is a front elevational view thereof, shown in connection with a sound-maker element.
[0030] FIG. 18 is a front elevational view of the sound-maker element as taken about the circle of FIG. 17 .
[0031] FIG. 19 is a side elevational view thereof.
[0032] FIG. 20 is a front elevational view thereof, shown in an unbent orientation.
[0033] FIG. 21 is a front elevational view of an alternative embodiment of FIG. 14 including front and rear image elements.
[0034] FIG. 22 is a three-dimensional isometric view thereof.
[0035] FIG. 23A is a front elevational view of the embodiment of FIG. 8 including front and rear image elements.
[0036] FIG. 23B is a side elevational view of the embodiment of FIG. 9 including front and rear image elements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
I. Introduction and Environment
[0037] As required, detailed aspects of the present invention are disclosed herein, however, it is to be understood that the disclosed aspects are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art how to variously employ the present invention in virtually any appropriately detailed structure.
[0038] Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, up, down, front, back, right and left refer to the invention as orientated in the view being referred to. The words, “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the aspect being described and designated parts thereof. Forwardly and rearwardly are generally in reference to the direction of travel, if appropriate. Said terminology will include the words specifically mentioned, derivatives thereof and words of similar meaning.
[0039] The four embodiment ornamentations disclosed herein could be used for any type of ornamentation, from household decorations (e.g. Christmas tree ornaments or wind chimes) to pendants, earrings, or other body decorations, to functional ornamentations for use as fishing lures. The twisting of the ornamentations promotes the spinning of the orientation when in contact with a fluid, such as water or air.
II. First Embodiment Functional Ornamentation 2
[0040] FIGS. 1, 2, 4-5, 10, and 12 show a first embodiment functional ornamentation 2 . The present invention is manufactured from a stamped plate having rounded ends and a wider central diameter “D 1 ” than the ends (see FIG. 2 ), which is in contrast to the most relevant prior art 11 (see FIG. 3 ), which has a much narrower central diameter “D 2 .” The widest point of the plate is approximately 36% as wide as the length of the plate, and the thinnest point of the plate at each end is approximately ⅓ of width of the center. The sides form an angle of approximately 150-155 degrees. Said another way—the central diameter D 1 is between sixty percent (60%) and seventy-five percent (75%) of a length L, where D 1 is the widest point of said main body blank, and where length L is the distance between a top-most point of said top end and a point along a line corresponding with said central diameter D.
[0041] The prior art, however, is only approximately 25% as wide as the length of the plate, and the thinnest point at each end only half as wide as the center. The angle formed is therefore approximately between 160-165 degrees. This variance lends a great deal of versatility to the present invention over the prior art.
[0042] FIGS. 1 and 4-5 show the first embodiment ornamentation 2 which includes two ¼ twists of the metal plate, resulting in a half twist or 180 degree twist of the entire blank. The piece can then be broken down to an upper end 4 , a lower end 6 , and the wide central portion 8 . Each end 4 , 6 has a mounting hole 10 for receiving connectors, such as linking rings 14 for fish hooks, fishing lures, earing hooks, or other items for connecting to the ornamentation 2 . In this orientation, the upper 4 and lower 6 ends are perpendicular to the central portion 8 .
[0043] To form this twist, and all of the various embodiments of the present invention, the blank as shown in FIG. 2 is heated, either using a torch or through some other method (e.g. running current through the blank), which allows the blank to become more malleable. At this stage, the blank can be twisted to the desired proportions. The blank is most likely made of brass, cold rolled steel, aluminum, or plastic. Twisting can be done by hand using a vice and vice grips or pliers, or could be performed by a machine.
[0044] No grinding or cutting of the blades is required. The punched template is heated and twisted into shape and the final product is then ready.
III. Second Embodiment Ornamentation 52
[0045] FIGS. 6 and 7 show a second embodiment ornamentation 52 which includes two ½ twists, or a full 360 degree twist of the entire blank. As before, this breaks the ornamentation 52 into a top portion 54 , a bottom portion 56 , and a central portion 58 . The top and bottom portions include mounting holes 60 .
IV. Third Embodiment Ornamentation 102
[0046] FIGS. 8 and 9 show a third embodiment ornamentation 102 which includes one ¼ twist on the top and one ½ twist on the bottom. Again, this separates the ornamentation 102 into a top portion 104 , a bottom portion 106 , and a central portion 108 . The top and bottom portions include mounting holes 110 .
[0047] FIG. 10 shows the first embodiment ornamentation 2 connected to a fishing hook 12 using a connection ring 14 . Any connector could be used to join the ornamentation 2 to the hook 12 . When used as a fishing lure, the ornamentation spins in the water and reflects light in such a way that it attracts fish better than other lures.
[0048] FIG. 11 is a similar combination of the second embodiment ornamentation 52 and the hook 12 and connection rings 14 . It should be noted that the fishing hook 12 could be any type of hook, including a hook for an earring to be worn for personal decoration, or for a Christmas tree ornament hook, or any type of mounting apparatus. Further, in the case of a fishing hook, bait could also be affixed.
[0049] FIG. 12 show the first embodiment ornamentation 2 , but includes a pair of leaf elements 16 connected to the mounting hole 10 by at least one connection ring 14 . If used as a fishing lure, while the ornamentation 2 is drawn through the water, it will spin in a corkscrew fashion. The leaves 16 will similarly be spun and will flare out away from the ornamentation itself, which will attract fish. A unique sound which attracts fish is also produced when this occurs. The leaves 16 are ideally made of metal and produce a knocking sound against the ornamentation 2 , which attracts fish when used as a lure.
V. Fourth Embodiment Ornamentation 152
[0050] FIGS. 13-16 show a fourth embodiment ornamentation 152 . Again, this embodiment begins as a flat blank as shown in FIG. 13 having an upper base portion 154 and two lower leg portions 156 split by a break 158 . Two mounting holes 160 are included. FIG. 14 shows the ornamentation 152 after being twisted into a final form, here including a fishing hook 12 connected to the mounting hole 160 by a connection ring 14 .
[0051] FIG. 15A shows a side elevational view of the ornamentation 152 , which also clearly shows the legs 156 bent at an angle “a” away from perpendicular. This angle would be between 0° (completely perpendicular to the upper base portion 152 ) and 45°. An ideal angle is 22.5°. Further, it is preferably that the twist of the upper base portion 152 continue partially into the bending of the legs 156 , whether the upper base portion 152 is twisted 90° (¼ twist) as shown, or 180° (½ twist). FIG. 15B shows how this embodiment is connected to a bait/hook combination 18 or other element via a connection ring 14 and swivel connection 17 . This allows free rotation of the ornamentation 152 about the swivel connection 17 when being drawn through the water or when hung as ornamentation. The legs 156 act as tails which catch the wind or the water and cause rotation. FIG. 16 shows another clear view of this embodiment.
[0052] FIG. 17 show the embodiment ornamentation 152 with an additional sound-maker element 162 , here shown connected via a connection ring 14 and swivel 16 . As the ornamentation spins 152 , the sound-maker element 162 knocks against the body of the ornamentation, making a ringing or knocking noise.
[0053] FIGS. 18-20 show the sound-maker element 162 in more detail. FIG. 12 shows how the sound-maker element 162 is formed from a flat tear-drop shaped blank with a mounting hole 164 . FIGS. 18 and 19 show a front and side view, respectively, of that blank when it is rolled into the sound-maker element which includes a pair of folded up wings 166 which cause the entire element to act like a bell, producing sound which attracts fish if used as a lure, or otherwise creates a pleasant sound if used as a wind chime or other ornamentation.
[0054] FIGS. 21 and 22 show the embodiment ornamentation 152 when used in conjunction with an image. FIG. 21 shows how a front face image 168 and rear face image 170 can be offset slightly such that when the ornamentation 152 spins about its axis, the resulting image, as shown in FIG. 22 , is presented as a three-dimensional flashing hologram 172 to the viewer. This is a result of the speed at which the ornamentation can spin, such as about a swivel connection 17 . The image could be any picture, or could be a cut-out portion of the upper base portion 154 .
[0055] Alternatively, as shown in FIGS. 23A and 23B , the image located on the ornamentation (the third ornamentation embodiment 102 ), could be a string of letters forming a word. Half of the letters 112 could be on one face of the blank, and half could appear on the other face, such that when the ornamentation 102 spins, the entire word is readable by a viewer. FIGS. 23A and 23B use the third embodiment ornamentation 102 , but any of the embodiment ornamentations 2 , 52 , 102 , 152 could be used here.
[0056] The lures created using the embodiments of the present invention travel through the water in a straight path and not along an arced path as required in the prior art. The shape and twist of the lures produces increased “flash” and spins absolutely horizontally or vertically (as oriented) on the top of the water, deep in the water, or in a vertical jig. The “flash” produced by the spinning twisting motion of the lures attracts more fish than lures of the prior art.
[0057] It is to be understood that while certain embodiments and/or aspects of the invention have been shown and described, the invention is not limited thereto and encompasses various other embodiments and aspects.
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A functional ornamentation manufactured from a stamped metal plate which is twisted by a specified number of degrees to result in a shape that allows for unique reactions to flowing fluids such as air and water. Due to the shape and twist of the device, the device will spin along with the flowing fluid or when pulled through that fluid, such that it retains a straight trajectory. In a preferred embodiment, such as part of a fishing lure, the ornamentation is connected to a ball bearing swivel which allows for near frictionless rotation. The lure when drawn through the water travels in a straight path, rather than an arced path of the prior art. This results in a more natural travel path producing greater flash and rotation for attacking fish.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a National Stage entry from PCT Patent Application No. PCT/GB2008/001256, filed Apr. 10, 2008, which claims priority to United Kingdom Patent Application No. GB0706909.9, filed on Apr. 10, 2007, the contents of each one incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a downhole apparatus and method for use in the completion of hydrocarbon wells, and in one aspect to a downhole screen including a swellable material and a method of use.
BACKGROUND
[0003] In the completion of hydrocarbon wells, it is known to use screens to prevent the production of solids from the formation. Expandable tubular technology has been used to expand metal screens to reduce the annular space around the screen and thereby reduce or eliminate the requirement for gravel packing and provide structural support for the formation.
[0004] There are a number of drawbacks to using expanding tubulars. It can be difficult to control the force used to expand the tubular, and there may be resulting problems with the application of an undue, damaging force onto the formation. Expandable tubulars also have a limited expansion range, which means that maximum expansion can still result in an unsupported formation in a wash out zone.
[0005] US 2005/0173130 describes an arrangement in which a swellable layer is located over an expanding screen to allow the apparatus to conform to the borehole shape. Holes in the swellable layer allow the passage of formation fluids. However, it is desirable in many applications to avoid the use of expanding tubulars. Additionally, by providing the screen around the expandable pipe at a location displaced from the borehole wall, there is an annular space into which solids may be produced, and along which solids may flow. This increases the risk of blocking the screen and creating so-called hotspots which are prone to erosion.
[0006] The proposal of WO 2006/003112 attempts to overcome these deficiencies by providing a screen which is expanded into contact with the borehole wall by swellable rings. This approach relies on overlaid screen sheets which are forced outward by the swelling of the rings. This has the undesirable effect of restraining expansion of the swellable material, which may only be capable of exerting a pressure of 50 to 100 PSI (345 to 690 KPa). In addition, the gaps between overlaid screen sheets provide route for solid particles to enter the production tubing.
SUMMARY
[0007] It is one aim of at least one aspect the invention to provide a downhole apparatus and method which overcomes or mitigates the deficiencies of previously proposed apparatus and methods.
[0008] It is another aim of at least one aspect of the invention to provide an alternative apparatus and method to those previously proposed.
[0009] It is an aim of at least one aspect of the invention to provide a downhole apparatus offering improved performance and or wider operating parameters than the apparatus of the prior art.
[0010] According to a first aspect of the invention there is provided a downhole apparatus comprising a main body having a bore arranged to be coupled with a well tubing; and a swellable mantle disposed on the main body, which swellable mantle expands upon contact with at least one predetermined fluid; wherein the main body comprises at least one opening for fluid flow between an exterior of the main body and the bore, and the swellable mantle is provided with an insert to permit the passage of fluid between the exterior of the apparatus and the at least one opening through the swellable mantle.
[0011] Thus the apparatus may permit fluid flow from its exterior into the bore, through the openings in the main body, and onward to the well tubing. The apparatus may therefore communicate with production tubing, and may be adapted to permit flow of production fluid from a producing zone into the production tubing.
[0012] The swellable mantle may be disposed around an elongate portion of the main body, and may form a substantially cylindrical member around the main body. The elongate portion may comprise at least one opening therein, and the swellable mantle may be adapted to allow the passage of fluid between the exterior of the apparatus and the at least one opening in the elongate portion. The apparatus may therefore be arranged to permit fluid flow across an area or surface over which the swellable mantle is disposed.
[0013] The main body may be a tubular, and may form a base pipe of the apparatus. The main body may comprise a liner tubular. Preferably, the main body comprises a plurality of openings. The openings may be slots or perforations. The main body may therefore be a slotted or pre-perforated tubular.
[0014] In a preferred embodiment, the main body is formed to a fixed diameter, and is not adapted for expansion in use.
[0015] The swellable mantle may be provided with at least one formation to promote fluid flow between the exterior of the apparatus and the at least one opening.
[0016] Preferably, the swellable mantle is provided with at least one aperture therein. The aperture may be a hole, groove or slot in the swellable mantle. The aperture may be a radial opening in the swellable mantle. The aperture may comprise a groove extending circumferentially of the swellable mantle, and may comprise an annular groove in the swellable mantle. Alternatively, or in addition, the aperture may comprise a groove extending longitudinally of the swellable mantle. The aperture may comprise a groove defining a groove axis, which may be oriented longitudinally, circumferentially, or helically of the swellable mantle.
[0017] The aperture may comprise a hole extending radially of the swellable mantle.
[0018] The aperture may provide a fluid flow path from the exterior of the apparatus to main body. The apparatus may comprise a flow path from the exterior of the apparatus to the bore, via the aperture and the at least one opening in the main body. The flow path may be from a producing formation to the bore, via the aperture and the at least one opening in the main body.
[0019] The insert may be provided in the aperture. The insert preferably permits fluid flow through the aperture. The insert may be adapted to maintain a flow path in the aperture. The insert may comprise a fluid permeable material. The insert may function as a filter for filtering solid particles from the fluid flowing through the aperture.
[0020] The insert may be disposed over one or more openings of the main body. The insert may extend longitudinally and/or radially of the main body. The insert may substantially fill a volume defined by the aperture. The insert may function to support or abut a portion of the swellable mantle, and may define a bearing surface for a portion of the swellable mantle. The insert may therefore limit or prevent the expansion of the swellable mantle in at least one direction, and may be arranged to prevent the expansion of the swellable mantle into the flow path defined by the aperture.
[0021] The insert may be formed from a permeable rope, a braided line or a fibrous material, which may be wound into the aperture. Alternatively, the insert may comprise a sintered metal component.
[0022] In a further alternative, the insert may comprise an impermeable metal component having fluid apertures formed therein. The insert may comprise an abrasion- or erosion-resistant material such as tungsten carbide or similar.
[0023] The insert may define a conduit in the swellable mantle. The insert may define a radially extending conduit through an aperture in the swellable mantle. The conduit may be a bounded conduit, which may be adapted to maintain a flow path in the aperture. The conduit may be defined by a tube. The conduit may extend from the exterior of the swellable mantle to main body. The conduit may have a first end arranged for fluid flow to and/or from an exterior of the apparatus and a second end arranged for fluid flow to and/or from the main body. The second end may be located at or adjacent to the main body. The second end may be coupled to the apparatus at an opening on the main body. Alternatively, the second end may fully or partially extend into main body. The second end may be bonded to the main body.
[0024] The conduit may be of variable length. The conduit may be telescopic, and may comprise a first member at the first end, movably coupled to a second member at the second end. The first and second members may therefore move relative to one another to create a channel of variable length. Such relative movement result from expansion of the swellable mantle. The second member may be bonded to the swellable mantle. The first member may be adapted to move relative to the second member on expansion of the swellable mantle. A seal may be provided between the first and second members.
[0025] In an embodiment of the invention, there is provided one or more flow-directing members or channels disposed on an outer surface of the apparatus. The flow-directing member may be adapted to couple multiple apertures, and or direct flow to multiple apertures. The flow-directing member may be provided with holes corresponding to apertures in the swellable mantle. The flow-directing member may provide a fluid path from the exterior of the apparatus to one or more apertures. The flow-directing member may be coupled to an insert to an aperture.
[0026] Preferably, the flow-directing member is coupled to multiple inserts, and may be integral therewith. More preferably, the flow-directing member is coupled to multiple conduits, or first members thereof. The flow directing member may partially or fully define the inserts to the apertures.
[0027] The flow-directing member and the inserts can be considered in one embodiment to function as a gutter and a series of drainpipes respectively.
[0028] Preferably, the apparatus comprises a screen for filtering solids between the exterior of the apparatus and the bore. Preferably the screen is arranged to filter solids from fluid flowing from the exterior of the apparatus to the bore. The screen functions to filter solids produced from the formation, such as sands or shale or the like, from the fluid. The screen may comprise a plurality of layers. The screen may comprise at least one mesh layer, but preferably comprises a plurality of mesh layers.
[0029] The screen may comprise a filter mesh layer having a filter grade of 50 microns to 350 microns. The screen may further comprise one or both of an outer protective shroud or a drainage support mesh layer. Preferably, the screen comprises a first drainage support mesh layer on one side of a filter mesh layer, and a second drainage support mesh layer on an opposing side of a filter mesh layer.
[0030] The screen is preferably disposed over the openings. More preferably, the screen is disposed over the apertures. The screen may be disposed in the flow-directing member.
[0031] The apparatus may comprise multiple screens at discrete locations. The apparatus may comprise at least two screens having different filter grades.
[0032] The swellable mantle is preferably disposed around the main body and may be arranged to expand upon contact with at least one predetermined fluid and thereby move the screen outwardly of the main body. The screen is preferably arranged such that any restraining force imparted by the screen onto the swellable mantle which acts against its expansion can be overcome by the swellable mantle. More preferably, substantially no restraining force is imparted on the swellable mantle by the screen.
[0033] The apparatus may be arranged such that the surface area of the screen is maintained in use, between an unexpanded condition and an expanded condition. The screen may have a screen surface area; and the swellable mantle may be disposed around the main body between the main body and the screen. Preferably, the swellable mantle is arranged to expand upon contact with at least one predetermined fluid and thereby move the outwardly of the main body while maintaining the screen surface area.
[0034] The swellable mantle may comprise a first region located between the main body and the screen which allows the passage of fluid between the exterior of the apparatus and the main body. The swellable mantle may include a second region, which may be circumferentially adjacent the first region, which substantially prevents passage of fluid between the exterior of the apparatus and the main body.
[0035] Preferably, the second region is adapted to be expanded into contact with the borehole wall.
[0036] The screen may be discontinuous around the circumference of the main body. The screen may consist of multiple portions of screening material, which may be discrete in an expanded condition of the apparatus. The multiple portions may additionally be discrete in an unexpanded condition of the apparatus. Preferably, the swellable member is disposed around the main body between the main body and the screen such that on expansion the screen is moved outwardly of the main body. The screen may comprise at least two discrete screens or screen sections circumferentially spaced on the apparatus.
[0037] Preferably, the swellable mantle is disposed between the main body and a borehole wall in use. The apparatus may be adapted to provide stand off of the main body from the bore in the apparatus is located. More preferably the swellable mantle is further adapted to provide support to a wall of the bore in which it is located.
[0038] The apparatus may be used to support a loose or unstable borehole formation, such as a sandstone or shale formation. The apparatus may be adapted for compliant expansion of the swellable mantle to the formation, such that the swellable mantle contacts the formation without unduly stressing the formation. This has the advantage of reducing rock fatigue and reducing the tendency of solids to flow out of the formation with the fluid.
[0039] Although the term “swellable mantle” is used herein it should not be taken to imply a single piece of swellable material unless otherwise specified. Certain embodiments of the invention comprise multiple, separate pieces of swellable material which combine to provide the so-called swellable mantle. Other embodiments comprise a unitary swellable mantle.
[0040] The swellable material may comprise an ethylene-propylene co-polymer cross-linked with at least one of a peroxide and sulphur. More specifically the swellable member may comprise ethylene propylene diene monomer rubber (EPDM).
[0041] Alternatively or in addition the swellable member may contain at least one or multiple water absorbing resins or more precisely any lightly cross-linked hydrophilic polymer embedded within the main swellable member elastomer which may comprise at least one of chloroprene, styrene butadiene or ethylene-propylene rubbers. Such water-absorbing resins are termed “superabsorbent polymers” or “SAPs” and when embedded within the swellable member it may expand when in contact with an aqueous solution.
[0042] Examples of water absorbent resin include cross-linked polyacrylic acid salts, cross-linked copolymers of vinyl alcohol and acrylic acid salt, cross-linked products of polyvinyl alcohol grafted with maleic anhydride, crosslinked copolymers of acrylic acid salt and meth-acrylic acid salt, cross-linked saponification products of methyl acrylate-vinyl acetate copolymer, cross-linked products of starch-acrylic acid salt graft copolymer, crosslinked saponification products of starch-acrylonitrile graft copolymer, crosslinked saponification products of starch-ethyl acrylate graft copolymer, crosslinked carboxymethyl cellulose and the like.
[0043] Alternatively or in addition, the swellable member may comprise an ethylene-propylene-diene polymer with embedded water absorbent resin such that expansion of the swellable member may result from contacting either an aqueous solution or polar liquid such as oil or a mixture of both.
[0044] According to a second aspect of the invention there is provided a well completion or hydrocarbon production method comprising the steps of:
[0000] a. Providing a swellable mantle over an opening on a main body of an apparatus;
b. Locating the apparatus at a downhole location;
c. Expanding the swellable mantle by exposing it to a predetermined fluid;
d. Maintaining a fluid flow path in the swellable mantle using an insert in the swellable mantle;
e. Allowing fluid flow between an exterior of the apparatus and the at least one opening through the swellable mantle.
[0045] The method may comprise the step of allowing fluid to flow through the insert. The method may comprise the step of receiving fluid from the formation and into a well tubing to which the apparatus is coupled.
[0046] The method may include the additional step of screening solids from the fluid received from the formation.
[0047] The method may include the additional step of moving a screen outwardly of the main body during expansion of the swellable mantle.
[0048] The method may include the step of expanding the swellable mantle without changing the surface area of the screen.
[0049] The method may include the step of expanding the swellable mantle such that the screen consists of a plurality of discrete screen sections after expansion.
[0050] Other preferred and optional features of the second aspect of the invention are defined with respect to the first aspect of the invention.
[0051] According to a third aspect of the invention there is provided downhole apparatus comprising a main body having a bore communicating with a well tubing, and at least one opening for fluid flow between an exterior of the main body and the bore; a screen for filtering solids between the exterior of the apparatus and the bore; and a swellable mantle disposed around the main body and arranged to expand upon contact with at least one predetermined fluid and thereby move the screen outwardly of the main body, wherein the swellable mantle comprises a first region located between the main body and the screen which allows the passage of fluid between the exterior of the apparatus and the main body; and a second region, circumferentially adjacent the first region, which substantially prevents passage of fluid between the exterior of the apparatus and the main body.
[0052] Thus the invention in this aspect provides a swellable mantle with a surface which is designed to permit or prevent fluid flow through circumferentially separated areas. This facilitates the use of a screen which is not continuous around the circumference of swellable mantle. The discontinuous nature of the screen permits the screen to be moved outwardly of the main body more readily than if a continuous screen were used.
[0053] Preferably, the second region is adapted to be expanded into contact with the borehole wall.
[0054] The screen is preferably arranged such that any restraining force imparted by the screen onto the swellable mantle which acts against its expansion can be overcome by the swellable mantle. More preferably, substantially no restraining force is imparted on the swellable mantle by the screen.
[0055] The apparatus may be arranged such that the surface area of the screen is maintained in use, between an unexpanded condition and an expanded condition. The screen may have a screen surface area; and the swellable mantle may be disposed around the main body between the main body and the screen. Preferably, the swellable mantle is arranged to expand upon contact with at least one predetermined fluid and thereby move the outwardly of the main body while maintaining the screen surface area.
[0056] The screen may be discontinuous around the circumference of the main body. The screen may consist of multiple portions of screening material, which may be discrete in an expanded condition of the apparatus. The multiple portions may additionally be discrete in an unexpanded condition of the apparatus. Preferably, the swellable member is disposed around the main body between the main body and the screen such that on expansion the screen is moved outwardly of the main body. The screen may comprise at least two discrete screen sections circumferentially spaced on the apparatus.
[0057] Other preferred and optional features of the third aspect of the invention are defined with respect to the first and second aspects of the invention.
[0058] According to a fourth aspect of the invention there is provided a well completion or hydrocarbon production method comprising the steps of:
[0000] a. Providing a swellable mantle over an opening on a main body of an apparatus;
b. Locating the apparatus at a downhole location;
c. Expanding the swellable mantle by exposing it to a predetermined fluid to thereby move a screen outwardly of the main body;
d. Allowing fluid to flow between an exterior of the apparatus and the at least one opening through a first region of the swellable mantle located between the main body and the screen, while substantially preventing passage of fluid between the exterior of the apparatus and the main body in a second region of the swellable mantle, circumferentially adjacent the first region.
[0059] The method may comprise the step of receiving fluid from the formation and into a well tubing to which the apparatus is coupled.
[0060] The method may include the additional step of screening solids from the fluid received from the formation.
[0061] The method may include the step of expanding the swellable mantle without changing the surface area of the screen.
[0062] The method may include the step of expanding the swellable mantle such that the screen consists of a plurality of discrete screen sections after expansion.
[0063] Other preferred and optional features of the fourth aspect of the invention are defined with respect to the first to third aspects of the invention.
[0064] According to a fifth aspect of the invention there is provided a downhole apparatus comprising a main body having a bore communicating with a well tubing, and at least one opening for fluid flow between an exterior of the main body and the bore; a screen for filtering solids between the exterior of the apparatus and the bore having a screen surface area; and a swellable member disposed around the main body between the main body and the screen, wherein the swellable member is arranged to expand upon contact with at least one predetermined fluid and thereby move the screen outwardly of the main body while maintaining the screen surface area.
[0065] Other preferred and optional features of the fifth aspect of the invention are defined with respect to the first to fourth aspects of the invention.
[0066] According to a sixth aspect of the invention there is provided a downhole apparatus comprising a main body having a bore communicating with a well tubing, and at least one opening for fluid flow between an exterior of the main body and the bore; a screen for filtering solids between the exterior of the apparatus and the bore; and a swellable member disposed around the main body between the main body and the screen, wherein the swellable member is arranged to expand upon contact with at least one predetermined fluid and thereby move the screen outwardly of the main body, wherein the screen comprises at least two discrete screen sections circumferentially spaced on the apparatus.
[0067] Other preferred and optional features of the sixth aspect of the invention are defined with respect to the first to fifth aspects of the invention.
[0068] Use of the first, third, fifth and sixth aspects of the invention in well completion or production methods is within the scope of the invention. A volume of hydrocarbon obtained by using the apparatus or methods described also forms part of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0069] There will now be described, by way of example only, various embodiments of the invention with reference to the following drawings, of which:
[0070] FIG. 1 is a perspective view of an apparatus in accordance with a preferred embodiment of the invention;
[0071] FIG. 2 is a perspective view of the apparatus of FIG. 1 with the swellable mantle removed to show other components;
[0072] FIG. 3 is an exploded view of the swellable mantle of the apparatus of FIGS. 1 and 2 ;
[0073] FIG. 4 is a perspective view of an insert used with the apparatus of FIGS. 1 , 2 and 3 ;
[0074] FIGS. 5A and 5B are schematic views of the insert of FIG. 4 in retracted and extended conditions respectively;
[0075] FIG. 6 is a schematic exploded view of a filter used in accordance with embodiments of the invention;
[0076] FIG. 7 is a schematic sectional view of the apparatus of FIG. 1 in use in a wellbore;
[0077] FIG. 8 is a schematic representation of apparatus in accordance with an alternative embodiment of the invention in partial longitudinal section;
[0078] FIG. 9 is a schematic representation of apparatus in accordance with a second embodiment of the invention in partial longitudinal section;
[0079] FIG. 10 is a cross-sectional view of apparatus in accordance with a further embodiment of the invention;
[0080] FIG. 11A is a cross-sectional view of apparatus in accordance with a further embodiment of the invention; and
[0081] FIG. 11B is a cross-sectional view of the apparatus of FIG. 11A in an expanded configuration.
DETAILED DESCRIPTION
[0082] Referring firstly to FIGS. 1 to 3 , there is shown a downhole apparatus, generally depicted at 10 , in accordance with an embodiment of the invention. The apparatus 10 comprises a main body 12 formed from tubular base pipe. The body 12 is adapted to be coupled to well tubing (not shown) such that the bore 14 of the apparatus communicates with the bore of the well tubing.
[0083] A section 16 of the main body 12 extending over a length of the apparatus is provided with openings 18 or perforations distributed longitudinally and circumferentially on the section 16 . The openings are through-openings from an exterior of the main body 12 to the bore 14 . In this embodiment, the openings 18 are regularly distributed, although in alternative embodiments other arrangements of openings may be provided.
[0084] Disposed over the main body 12 is a swellable mantle 20 . FIG. 2 shows the mantle removed from the apparatus 10 . The swellable mantle 20 is a substantially tubular member shaped to fit over the section 16 of the apparatus. The swellable mantle is sized to be bonded or slipped onto the main body, and is located on the section 16 by end rings 22 . The end rings 22 are secured to the main body to prevent axial and radial movement and to abut the respective ends of the swellable mantle 20 .
[0085] The swellable mantle 20 is provided with apertures 24 and inserts 26 to the apertures. The inserts 26 are located in longitudinal recessed grooves 28 on the outer surface of the swellable mantle 20 . The inserts 26 will be described in more detail below.
[0086] The swellable mantle 20 is formed from a material which is selected to expand on contact with a predetermined fluid. Such swellable materials are known in the art. In this example, the swellable mantle is required to swell in oil, and the material comprises ethylene propylene diene monomer rubber (EPDM). In an alternative embodiment, where the swellable mantle is required to swell in water, the material comprises any lightly crosslinked hydrophilic polymer embedded within the main swellable member elastomer, such as at least one of chloroprene, styrene butadiene or ethylene-propylene rubbers. Such water-absorbing resins are termed “superabsorbent polymers” or “SAPS” and when embedded within the swellable member may expand when in contact with an aqueous solution. In a further alternative embodiment, the swellable member comprises an ethylene-propylene-diene polymer with embedded water absorbent resin such that expansion of the swellable member results from contacting either an aqueous solution or polar liquid such as oil or a mixture of both.
[0087] The apertures 24 function to allow fluid to flow from the exterior of the swellable mantle 20 to its interior. When the swellable mantle is positioned on the main body 12 , the apertures 24 allow fluid flow from the exterior of the apparatus to the main body 12 and through the openings 18 in the main body to the bore 14 . In this embodiment, the spacing of the apertures 24 corresponds to the spacing of the openings 18 , such that the apertures 24 and openings 18 may be aligned to provide minimal resistance to fluid flow from the exterior of the apparatus to the bore 14 .
[0088] The swellable mantle 20 functions to expand on contact with a well bore fluid such that the outer surface of the apparatus comes into contact with the borehole wall. The dimensions and properties of the swellable mantle are selected for compliant expansion of the swellable mantle into contact with the borehole wall, such that an appropriately low force is imparted to the borehole to create a seal, but to prevent damage to the rock formation or sandface. The dimensions and material of the swellable mantle are also selected to expand into a washout zone in the borehole to similarly create a seal with a suitably low force on the formation. In this way, the formation is supported from collapse towards the main body 12 , but without damaging the formation in a way that would increase the inflow of solids.
[0089] The insert includes a screen support 30 and screen material 32 . The insert 26 therefore defines screen sections 33 of the apparatus along circumferentially spaced longitudinal regions of the swellable mantle 20 . Disposed between the screen sections are longitudinal regions of the swellable mantle 20 which substantially prevent fluid flow to the interior of the mantle 20 . In this regard, it is noted that the swellable material may permit fluid penetration by diffusion through the swellable material, but does not permit fluid flow such as that required for the inflow of production fluids into the bore 14 or the injection of fluids from the bore 14 into the formation.
[0090] FIGS. 4 , 5 A and 5 B show the insert 26 in more detail, with the screen material 32 removed. The insert 26 includes a plurality of conduits 34 which extend through the swellable mantle to the main body. Multiple conduits are connected by a channel 35 defined by the screen support 30 . The conduits 34 each comprise a first member 36 received in a second member 38 . The first and second members 36 , 38 are movable relative to one another to accommodate expansion of the swellable mantle 20 . The conduits function to maintain the flow path of the aperture after expansion. In alternative embodiments of the invention, the conduits, or a subset of conduits, are provided with flow control members such as valves or check valves to restrict fluid flow therethrough.
[0091] When assembled, the second member 38 is an interference fit with the aperture 24 of the swellable mantle into which it locates. The undersurface 42 of the screen support 30 is bonded to the surface of the swellable mantle 20 along the longitudinal groove 28 . When the swellable mantle expands, the first member 36 moves relative to the second member 38 such that the conduit telescopically extends.
[0092] In alternative embodiments, the second member 38 may be fixed to the main body 12 and/or may be received in the opening 18 in the main body.
[0093] Referring now to FIG. 6 , the screen material 32 is shown as comprising a plurality of overlaid layers. Adjacent the screen support 30 is provided a drainage support mesh 44 , onto which is overlaid a filter mesh 46 . The filter mesh is selected to have an appropriate mesh grade for filtering solids which may be produced from the formation. Typically, the filter mesh will have a mesh grade of around 100 to 300 microns. Over the filter mesh 46 is a further drainage support mesh 48 , and finally an outer protective shroud 50 , having relatively large apertures, is provided on the exterior of the screen material.
[0094] The present invention encapsulates embodiments in which different screen sections are provided with different filter grades. The invention also facilitates customisation of the apparatus by selecting appropriate filter grades during assembly of the apparatus.
[0095] FIG. 7 shows the apparatus 10 in use in a borehole, in a swelled condition. The apparatus 10 has been run to a location in a sand-producing formation 51 , and exposure to wellbore fluids has caused the swellable mantle 20 to expand into contact with the borehole wall 52 . As expansion takes place, the conduits 34 defined by the inserts 26 telescopically extend such that a bounded conduit is formed between the exterior of the apparatus and the openings 18 in the main body 12 . The inserts prevent the swellable mantle 20 from expanding to close the apertures 24 .
[0096] The screen sections 33 are placed adjacent to the sandface by expansion of the swellable mantle under the insert, and adjacent regions 54 of the swellable mantle form a compliant seal on the borehole wall 52 . Fluid flow from the formation is permitted in the areas at which the screen sections 32 are provided, and is directed through the apertures 24 , via the conduits 34 , and into the bore 14 . Flow is not permitted through the regions 54 .
[0097] This embodiment of the invention provides compliant expansion of a swellable member to a borehole wall, providing structural support to the borehole without damaging the sandface. The screen sections 33 are carried or moved in a radial direction to be placed adjacent to the sandface. This minimises the annular space in which solids produced from the formation can flow. The flow of fluid is only permitted in the regions at which the screen material is provided, with adjacent sections supported and sealed by the swellable mantle. By providing the plurality of discrete screen sections, movement of the screen outwardly from the main body of the apparatus is accomplished effectively without restraining swelling of the mantle. The embodiment of the invention is also conducive to customisation and configuration of the filter grades used, which may differ between screen sections.
[0098] There will now be described alternative embodiments of the invention with reference to FIGS. 8 to 11 .
[0099] Referring to FIG. 8 , there is shown a downhole apparatus, generally depicted at 100 consisting of the main body 112 formed from a tubular base pipe and adapted to be coupled to well tubing in the same manner as apparatus 10 . In a similar fashion to apparatus 10 , the main body 112 is provided with a plurality of through-openings 118 distributed on the body.
[0100] Disposed on the body 112 , and shown in the Figure in longitudinal section, are end rings 122 and a swellable mantle 120 consisting of three longitudinally spaced sections 121 a , 121 b , and 121 c . Apertures 124 are provided in the form of circumferential grooves to the swellable mantle 120 extending from its outer surface to the main body 112 . Provided in the apertures 124 are inserts 126 , which in this embodiment are constructed from a permeable rope which is wound around the main body into the aperture. The insert 126 is wound tightly on the main body and provides an abutting surface for the adjacent portions of the swellable mantle 120 . In use, the swellable mantle expands outwardly and partially over the insert 126 , but without covering the aperture to prevent fluid flow.
[0101] The inserts 126 function to permit fluid flow through the aperture and into the main body, while maintaining the flow path and limiting or preventing the expansion of the swellable mantle in the longitudinal direction. The insert additionally functions as a filter for solid particles in the fluid flowing through the aperture.
[0102] In an alternative embodiment, the insert 126 is wound from a braided line or wire, or a fibrous material.
[0103] FIG. 9 shows an alternative embodiment, generally depicted at 130 , similar to the embodiment of FIG. 8 and with like components identified by like reference numerals. This embodiment differs in the form of the inserts 136 , 138 provided to the apertures 124 .
[0104] Insert 136 is in the form of a cylinder sized to slip onto the main body 112 , and provided with first and second flange members 137 a , 137 b extending outwardly from the main body. Holes are provided in the insert 136 to allow fluid flow to the main body. The flange members 137 a and 137 b function to provide an abutting surface to adjacent portions of the swellable mantle to limit or prevent expansion of the swellable mantle across the aperture 124 . Insert 138 consists of a pair of flange portions extending outwardly from the main body, and exposing the main body to the aperture 124 .
[0105] In this embodiment, one or both of the inserts of 136 , 138 may comprise a hardened, erosion-resistant material such as tungsten carbide. This functions to resist erosion caused by solid particles contained in the fluid, which would have a tendency to erode the swellable mantle and/or the openings in the main body 112 . It will be appreciated that the apparatus may comprise only one type of the inserts 136 , 138 .
[0106] FIG. 10 shows a further alternative embodiment of the invention, generally depicted at 140 . In this embodiment, the apertures 144 and the swellable mantle 146 are longitudinal grooves, at the inserts 146 are formed from blocks of sintered metal material. The blocks of sintered metal material are overlaid with screen sections 148 before filtering solids from fluid flowing through the apertures 144 and into the main body. In use, the swellable mantle expands outwardly and partially over the screen section, but without covering the aperture to prevent fluid flow. In alternative embodiments, the apertures 144 are helical or circumferential slots or holes in the swellable mantle.
[0107] A further alternative embodiment is shown in FIGS. 11A and 11B . In this embodiment, shown generally at 150 , a substantially tubular screen 152 is embedded into a swellable mantle 153 . Apertures 158 are provided in the mantle 153 to allow fluid flow to the main body 159 . The screen 152 comprises longitudinal support members 154 which function to provide support to the relatively flexible screen material 156 . In FIG. 13A , the screen material is folded, bent or creased to such that is radial dimension is less than the maximum radial dimension which can be defined by the screen 152 . The screen has a fixed surface area, but is embedded into the swellable mantle such that it may expand radially on expansion of the swellable material to a position shown in FIG. 13B , without stretching the screen material or affecting the filter grade.
[0108] Variations to the above-described embodiments are within the scope of the invention. For example, any of the described insert configurations could be used in combination on the same apparatus in the scope of the invention. Combinations of features other than those expressly claimed are within the scope of the invention.
[0109] In further alternative embodiments of the invention, the apertures, or selected apertures in the swellable mantle, are provided with flow control members such as valves or check valves to restrict fluid flow therethrough.
[0110] The present invention in its various aspects provides an improved and alternative downhole apparatus and method offering improved performance and/or wider operating parameters than the apparatus of the prior art.
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A downhole apparatus is described comprising a main body coupled with a well tubing and a swellable mantle disposed on the main body. The swellable mantle expands upon contact with at least one predetermined fluid, and the main body comprises at least one opening for fluid flow between an exterior of the main body and the bore. An insert permits the passage of fluid, through the swellable mantle, between the exterior of the apparatus and the opening. In one aspect of the invention a screen filters solids between the exterior of the apparatus and the bore, and a swellable mantle comprises a first region which allows the passage of fluid between the exterior of the apparatus and the main body and a second region, circumferentially adjacent the first region, which substantially prevents passage of fluid. Corresponding well completion and production methods are also described.
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PRIORITY
[0001] This application claims priority from application Ser. Nos. 10/195,924, 10/195,945 and 10/197,050, all of which claim priority from both the provisional application entitled “Tape Measure that Incorporates a Marking Device” filed by Dane Scarborough on Dec. 18, 2001, with Ser. No. 60/342,146, and the provisional application entitled “Tape Measure that Incorporates a Marking Device” filed by Dane Scarborough on Feb. 28, 2002 with Ser. No. 60/360,698. This application further claims priority from application serial number (unknown), filed on Jan. 6, 2004 bearing the title “Tape Measure that Incorporates a Marking Device.”
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to measuring devices and more specifically it relates to a tape measure that incorporates a marking device for allowing an individual to measure and mark a wide variety of materials in a more efficient and economical manner.
[0004] 2. Description of the Prior Art
[0005] Various different forms and types of measuring devices are known to the prior art. One particular type of measuring device is known as a “tape measure.” Tape measures typically comprise a flexible tape resiliently coiled within a housing. The tape is normally printed with incremental measuring marks for measuring distances. In use, the flexible tape is uncoiled and extended from the housing and placed on a surface to be measured. Distances can then be marked with a separate marking tool, such as a pencil, directly onto the surface measured.
[0006] Numerous devices incorporating marking tools inside and outside the tape measure housing are known in the prior art. These include devices which are affixed to existing tape measure housings, for instance, the self adhesive scoring attachment of U.S. Pat. No. 6,041,513 (Doak). These devices also include marking tools which are affixed to belt clips of existing tape measure housings. In example, U.S. Pat. No. 4,760,648 (Doak et al.) which discloses a marking device adapted to be mounted on one side of the tape measure, namely as a replacement belt clip.
[0007] These devices also include housings configured for receipt therethrough of marking means, such as pencils or pens. In example, U.S. Pat. No. 5,735,052 (Lin) discloses a tape measure having formed therein a passage for receiving therethrough the marking means.
[0008] These devices also include marking tools which are integral with the tape measure housing. For instance, U.S. Pat. No. 5,435,074 (Holevas et al.) discloses a tape measure having a marker attached to the tape measure's lock so that depression of the lock mechanism also extends the marker out of the housing of the tape measure. Also, U.S. Pat. No. 4,015,337 (Taylor) discloses a marking device integrally formed into the housing of the tape measure.
[0009] These devices can also include scoring means rather than marking (ink, graphite, etc.) means. For instance, U.S. Pat. No. 2,649,787 (Kobayashi), U.S. Pat. No. 3,063,157 (Keene), and U.S. Pat. No. 3,526,964 (Clark, Jr.).
[0010] The main problems with these conventional measuring devices are maintenance, inaccuracy, and lack of versatility.
[0011] Prior art marking means include the use of pencils, pens, scribes, chalk, and/or crayons. These methods of marking require continued maintenance in the form of refilling, sharpening, and/or adjusting the height or position of the marking instrument. Every time these marking means are subject to routine maintenance, inaccuracies become possible.
[0012] Another disadvantage is the fact that these methods for marking are limited in the scope of materials they can mark. For example, it is difficult to use a pencil, pen, or scribe to mark glass or ceramic tile. Conversely, it would not be preferable to use a felt marker or pen to mark material that will receive a clear finish or a painted finish wherein the mark of the pen or marker may bleed through the finish.
[0013] Another problem with conventional measuring devices are the number of procedures required to complete the task of measuring and marking materials accurately. These prior art devices require that the tape measure blade be locked into position prior to the use of the marking device. For instance, the patent to Holevas et al. discussed above. Such use can require additional digital manipulation of the tape measure, and due to the contact of the locking mechanism to the blade, can cause the tape measure blade to shift from the desired position, thereby causing inaccuracies.
[0014] Other problems with conventional measuring devices are their size and complexity. Many prior art devices have protrusions that inhibit or eliminate the ability to carry the tape measure in the standard pouch or holder that is often provided on a carpenter's or tradesmen's tool belt. Furthermore, if the tip of the marking instrument is exposed, it can cause damage or harm to other objects, or it can be damaged itself.
[0015] Prior art measuring tapes with retractable marking instruments require a mechanical means to do so. This retraction means also requires additional moving parts, which increase cost, increase the number of procedures for use, as well as increase the probability of malfunction.
[0016] What is needed is a tape measure, or a marking device able to be utilized with a tape measure, which is readily able to allow an individual to measure and mark a wide variety of materials in an efficient and economical manner; can be used for measuring and marking both the beginning point of reference and the measured position point simultaneously; requires little to no maintenance; is not prone to inaccuracy; is versatile; can be used to mark a wide variety of materials; is simple to use; is compact and not awkwardly shaped; and/or is not prone to damage when in or out of use.
[0017] In these respects, a tape measure that incorporates a marking device according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the above needs.
SUMMARY OF THE INVENTION
[0018] In view of the foregoing disadvantages inherent in the known types of measuring devices found in the prior art, the present invention provides a new tape measure that incorporates a marking device construction wherein the same can be utilized for allowing an individual to measure and mark a wide variety of materials in a more efficient and economical manner. Another purpose of the present invention is for measuring and marking the beginning point of reference and the measured position point simultaneously.
[0019] The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new tape measure that improves on the teachings of the prior art. In doing so, the present invention has many of the advantages of the measuring devices mentioned heretofore, and many novel features. The result is a new tape measure that incorporates a marking device which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art measuring devices, either alone or in any combination thereof.
[0020] The preferred embodiment of the present invention generally comprises a housing, a coiled measuring tape, a tape tip, and a marker for applying a mark to a surface to be measured and marked.
[0021] In the preferred embodiment, the housing is preferably an elongated square or cylindrical shape or a combination thereof, having opposed side walls, a top wall, a bottom wall, a rear wall, and a front wall defining an enclosure. The front wall having therethrough a tape blade aperture. The bottom wall or a portion thereof may be angled in such a way as to allow for engagement of the tape tip to the surface being measured without initiating contact of the marking portion until it is intended.
[0022] The coiled measuring tape is an elongated blade formed of a ribbon of metal or composite material coiled on a means for a spool with a means to retract. The tape tip of the measuring tape attaches to the end of the measuring tape and preferably comprises a means for hooking, including a hook portion that extends at an essentially right angle from the mounting portion of the tape tip. The tape tip may include a mark making means that is separate and independent from the marking portion on the housing. The marking portion on the housing preferably has a circular shaped wheel made of a rigid material such as metal, plastic or a mark making composite. The wheel preferably has an aperture for mating with an axle. This axle is preferably an elongated cylindrical shape.
[0023] The holder embodiment or marker enclosure is preferably an elongated tubular square in shape. It has a means of attachment to the housing in one embodiment. In another embodiment, the marker enclosure is integral with said housing. It preferably has a protruding cursor that is in alignment with a means for holding a marking wheel parallel to the face of the housing and perpendicular to the tape. The means for locking the tape blade has a button section that protrudes to the exterior of the housing.
[0024] There has thus been outlined, rather broadly, the more important features of the invention so that the detailed description thereof may be better understood, and so that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter.
[0025] In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.
[0026] A primary object of the present invention is to provide a tape measure that incorporates a marking device that will overcome the shortcomings of the prior art devices, preferably either through an improved tape measure or an attachment for an existing tape measure.
[0027] An object of the present invention is to provide a tape measure that incorporates a marking device for allowing an individual to measure and mark a wide variety of materials in a more efficient and economical manner.
[0028] Another purpose of the present invention is for measuring and marking the beginning point of reference and the measured position point simultaneously.
[0029] Another object is to provide a tape measure that incorporates a marking device that is directional by nature when engaged with a surface to be measured.
[0030] Another object is to provide a tape measure that incorporates a marking device that can measure and mark two positions simultaneously.
[0031] Another object is to provide a tape measure that incorporates a marking device that does not require maintenance to the marking device.
[0032] Another object is to provide a tape measure that incorporates a marking device that can measure and mark with one hand operation in a single economical movement.
[0033] Another object is to provide a tape measure that incorporates a marking device that once engaged with the material being measured, will accurately hold its position while the mark is being made, without the use of an optional mechanical locking device.
[0034] Another object is to provide a tape measure that incorporates a marking device that can fit into a common tape pouch or holder on a carpenter's tool belt.
[0035] Another object is to provide a tape measure that incorporates a marking device that can engage material to be measured and marked without damaging the material to be marked.
[0036] Another object is to provide a tape measure that incorporates a marking device that in one embodiment, has no moving parts.
[0037] Another object is to provide a tape measure that incorporates a marking device that is interchangeable and/or replaceable with an optional marking portion.
[0038] Another object is to provide a tape measure that incorporates a marking device that can cut a variety of materials.
[0039] Another purpose is for measuring and marking the beginning point of reference and the measured position point simultaneously.
[0040] To the accomplishment of the above and related objects, embodiments of this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated. Embodiments of the present invention accomplish one or more of the above purposes.
[0041] Further, the purpose of the foregoing abstract is to enable the United States Patent and Trademark Office and the public generally, and especially the scientists, engineers, and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measure by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
[0042] Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description wherein I have shown and described only the preferred embodiment of the invention, simply by way of illustration of the best mode contemplated by carrying out my invention. As will be realized, the invention is capable of modification in various obvious respects all without departing from the invention. Accordingly, the drawings and description of the preferred embodiment are to be regarded as illustrative in nature, and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Various other objects, features and advantages of the present invention will become fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views.
[0044] FIG. 1 is a perspective view of one embodiment of the present invention.
[0045] FIG. 2 is a front view of the embodiment shown in FIG. 1 .
[0046] FIG. 3 is a side view of the embodiment shown in FIG. 1 .
[0047] FIG. 4 is a bottom view of the embodiment shown in FIG. 1 .
[0048] FIG. 5 is an environmental perspective view of the embodiment shown in FIG. 1 .
[0049] FIG. 6 is a front view of a second embodiment of the present invention.
[0050] FIG. 7 is a side view of the embodiment shown in FIG. 6 .
[0051] FIG. 8 is a partial side, close-up view of the marking/cutting device of the embodiment shown in FIG. 6 .
[0052] FIG. 9 is a partial, close-up front view of the embodiment shown in FIG. 6 .
[0053] FIG. 10 is a side environmental view of the embodiment shown in FIG. 6 engaging material to be marked.
[0054] FIG. 11 is a front view of a third embodiment of the present invention in position to measure.
[0055] FIG. 12 is a front view of the embodiment shown in FIG. 11 in position to mark.
[0056] FIG. 13 is a front view of the embodiment shown in FIG. 11 showing the angled bottom of the housing in relationship to the tape tip and the marking portion.
[0057] FIG. 14 is a side view of the embodiment shown in FIG. 11 showing the angled bottom of the housing in relationship to the tape tip and the marking portion.
[0058] FIG. 15 is a front view of a fourth embodiment of the present invention.
[0059] FIG. 16 is a side view of the embodiment shown in FIG. 15 .
[0060] FIG. 17 is a front view of a fifth embodiment of the present invention showing a dual marking portion with a flexible housing bottom.
[0061] FIG. 18 is a side view of the embodiment shown in FIG. 17 showing a dual marking portion with a flexible housing bottom.
[0062] FIG. 19 is a side view of a sixth embodiment of the present invention engaged with a surface to be measured and marked.
[0063] FIG. 20 is an overhead view of the embodiment shown in FIG. 19 engaged with a surface to be measured and marked.
[0064] FIG. 21 is a front, close-up view of a tape tip containing a marking portion of one embodiment of the present invention.
[0065] FIG. 22 is a side, close-up view of a tape tip containing a marking portion of one embodiment of the present invention.
[0066] FIG. 23 is an overhead view of a tape tip of some embodiment of the present invention.
[0067] FIG. 24 is a side view of one embodiment of the housing with means for attachment.
[0068] FIG. 25 is a perspective view of one embodiment of the means for holding and the marking portion.
[0069] FIG. 26 is a perspective view of the means for holding and the marking portion shown in FIG. 25 .
[0070] FIG. 27 is a front view of the means for holding and the marking portion shown in FIG. 25 .
[0071] FIG. 28 is a top view of the means for holding and the marking portion shown in FIG. 25 .
[0072] FIG. 29 is a bottom view of the means for holding and the marking portion shown in FIG. 25 .
[0073] FIG. 30 is a side view of the means for holding and the marking portion shown in FIG. 25 .
[0074] FIG. 31 is a perspective view of one embodiment of the marking portion.
[0075] FIG. 32 is a side view of the marking portion shown in FIG. 31 .
[0076] FIG. 33 is a front view of the marking portion shown in FIG. 31 .
[0077] FIG. 34 is a side view of a seventh embodiment of the present invention.
[0078] FIG. 35 is a partial, cross-sectional view of the marking portion of FIG. 34 .
[0079] FIG. 36 is a partial, cross-sectional view of another embodiment of a marking portion.
[0080] FIG. 37 is a front view of another embodiment of the present invention shown in position to mark.
[0081] FIG. 38 is a perspective view of a tape measure bearing yet another embodiment of a means of marking of the present invention.
[0082] FIG. 39 is a partial, first end view of the tape measure of FIG. 39 .
[0083] FIG. 40 is a partial, side view of the tape measure means of marking of FIG. 38 .
[0084] FIG. 41 is a perspective view of another embodiment of the present invention.
[0085] FIG. 42 is a first side view of another directional marker of the present invention.
[0086] FIG. 43 is a first side view of yet another directional marker of the present invention.
[0087] FIG. 44 is a perspective view of one embodiment of a pen-style directional marker of the present invention.
[0088] FIG. 45 is a partial, side view of the embodiment of FIG. 45 .
[0089] FIG. 46 is a partial, close up view of the embodiment of FIG. 45 .
[0090] FIG. 47 is a side view of a second embodiment of a pen-style directional marker of the present invention.
[0091] FIG. 48 is a partial, sectional view of one embodiment of a mechanical pencil-style directional marker of the present invention.
[0092] FIG. 49 is an exploded view of the embodiment of FIG. 48 .
[0093] FIG. 50 is a partial, close up view of a second embodiment of a mechanical pencil-style directional marker of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0094] While the invention is susceptible of various modifications and alternative constructions, certain illustrated embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms or embodiments disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims.
[0095] Turning now descriptively to the drawings in which similar reference characters denote similar elements throughout the several views, the attached figures illustrate embodiments of the present invention. In one embodiment, the present invention is a tape measure that incorporates a marking device. In another embodiment, the present invention comprises a marking device able to be attached to a tape measure.
[0096] Referring initially to FIGS. 1-5 , shown is one embodiment of the present invention 10 . This embodiment comprises a tape measure 2 incorporating a marking portion or “marking device” 80 . This improved tape measure comprising a housing 20 , a coiled measuring tape 40 having measuring indicia thereon, a tape tip 60 , a marking device or marking portion 80 , an axle 100 , an “enclosure” or holder 120 , and a means for locking the tape blade 140 . The present invention is configured to be used upon a surface to be measured and marked 160 .
[0097] The housing 20 is preferably an elongated square, a cylindrical shape or a combination thereof, as shown in the figures. Many different shapes and styles of tape measure housings are known to the prior art and may be configured for use with the present invention. The preferred housing 20 having opposed side walls 22 , 24 , a top wall 26 , a bottom wall or base 28 , a rear wall 30 , and a front wall 32 . These walls defining an enclosure for holding a wound tape blade. The front wall 32 having a tape blade aperture 34 therethrough for allowing a measuring tape blade to be extended.
[0098] In the preferred embodiment, the coiled measuring tape 40 is an elongated blade formed of a ribbon of metal or composite material coiled on a spooling means, such as a spool, with a retraction means, such as a spring mechanism. Such type of coiled blade with spring tape measures are common in the prior art. The tape tip 60 or means for hooking is able to hook onto the edge of the surface to be marked, such as the edge of a board. This tape tip preferably including a hook portion 62 that extends at an essentially right angle from the mounting portion 66 of the tape tip 60 . The use of the phrase “coiled measuring tape” is expressly intended to include all other means for measuring, including laser, proximity sensors, sonar, etc.
[0099] The holder or enclosure 120 of the marking portion 80 is preferably generally elongated square in shape or a combination thereof or any other shape that would effectively house a marking device. In some embodiments, the holder 120 comprises a means of attachment to the housing, whereas, in other embodiments the holder 120 may be integrally formed within the housing 20 of the tape measure. In the embodiment shown in FIG. 1 , the marking device 80 attaches to the housing 20 at the front wall 32 . In such a configuration, the rim 88 of the impression wheel 84 extends from the housing 20 in position to contact the surface to be marked adjacent the portion of the tape extending out of the housing, thereby allowing a user to mark the surface corresponding to a desired indicia marking on the tape of the tape measure.
[0100] In use, particularly as shown in FIG. 5 , the tape tip 60 is hooked on the edge 162 of the surface to be measured 160 . The housing 20 then moved away from the edge 162 thereby extending the tape 40 . Side-to-side movement of the housing at the desired mark location results in the marking portion 80 making a mark on the surface to be measured and marked 162 which is generally perpendicular to the axis of the length of the tape 40 , this mark correlating to a particular measurement position on the tape.
[0101] As shown in FIGS. 25-30 , the holder 120 may also have a protruding cursor 124 that is in alignment with the marking wheel or “impression wheel” 84 of the marking portion 80 . Thus, the cursor 124 gives the user of the present invention an indication of where the marking wheel 84 of the marking portion 80 is aligned, thereby indicating the alignment of the mark to be made by the marking portion.
[0102] Referring back to FIGS. 1-5 , the present invention 10 preferably also comprises a means for locking 140 the tape blade 40 in position. This means for locking 140 has a button section 144 that protrudes to the exterior of the housing 20 . Means for locking tape blades of tape measures, in general, are known in the prior art. The means for locking 140 is completely optional, in that the present invention, unlike many of the prior art devices, will work absent such a means for locking. This is due to the fact that the marking portion 80 is directional, able to create generally a straight line mark generally perpendicular to the extension of the measuring means. Thus, once the marking portion is placed against the surface to be marked at the location of the mark to be made, the tape itself does not need to be locked into place, but could even be retracted. The present invention is superior over the prior art in that the marking process is as easy as extending the housing to the point to be marked, and marking the surface to be marked. No additional steps are required, for instance, the lock does not need to be engaged or the marking portion engaged. Each additional step required can result in errors or variances in location of the marking portion from the point intended to be marked. The present invention, in eliminating these additional steps, thereby results in a more accurate measurement.
[0103] It is preferred that the housing of the present invention be made of a rigid material such as metal, plastic, rubber, composite or a combination thereof. It is preferred that the tape blade of the present invention be made of a resilient material, such as metal, plastic or a composite. It is preferred that the marking wheel be made of a material able to itself leave or create a mark upon or into the surface to be marked. For instance, the wheel could be made of a hard metal, such as steel. The marking wheel could likewise be made of different materials for the different purposes discussed within this application, including, but not limited to metal, composites, rubber, plastic, natural materials, foam, etc. Likewise, the shape of the marking wheel can be as necessary, including but not limited to: rounded, flat, angled, sharpened, solid, porous, etc.
[0104] Referring now to FIG. 5 , the tape tip of the present invention preferably includes a means for hooking the tape tip on the edge 162 of a surface to be measured 160 . This means for hooking having a hook portion 62 that extends at an essentially right angle from the mounting portion 66 of the tape tip 60 . Such tape tips are standard for tape measures in the prior art.
[0105] Referring now to FIGS. 22-23 , the tape tip 60 comprises a means for hooking including a hooking portion 62 that extends at an essentially right angle from the mounting portion 66 of the tape tip 60 . Preferably, the tape tip 60 extends below the bottom 28 of the housing, as shown in FIG. 17 to allow the hooking part 62 to easily engage the edge 162 of the surface to be measured and marked 160 . As seen in FIG. 15 , the tape tip 60 may be of an asymmetrical shape to allow for increased engagement of the tape tip 60 to the surface to be measured and marked 160 .
[0106] Optionally, the tape tip 60 may include a mark making means 180 , for instance as shown in FIGS. 15-16 , 22 - 23 . In FIGS. 15 and 16 , the marking portion 80 may be a serrated edge or the edge of the tape tip 60 itself may be embedded with a mark making means such as diamond particles or a means for leaving a mark. Whereas in FIGS. 21-23 , the tape tip 60 itself may include a mark making means 180 .
[0107] In FIGS. 21-23 , the marking portion 180 preferably comprises a circular shaped wheel 184 or portion thereof. It is preferred that the marking portion 180 be made of a rigid material such as metal, plastic or a mark making composite. One example material is magnesium. While the marking portion 180 does leave an mark on the surface to be marked, it is important that the marking portion 180 not be easily consumed or worn, for instance as a graphite pencil would be. Thus, it is preferred that the marking portion leave a mark, score, or cut the surface rather than itself being readily consumed through its contact with the surface. Example metals which leave a mark without being consumed include, but are not limited to: magnesium, magnesium alloys, etc.
[0108] The wheel 184 preferably has an aperture 182 for mating with an axle. The axle 100 is preferably an elongated cylindrical shape. Likewise, this tape tip 60 has a hooking portion 62 and a mounting portion 66 . This marking portion 180 able to be configured for applying a mark as any other marking portion 80 , 180 disclosed herein. The preferred embodiment of a wheel 184 utilized with the present invention can be found in FIGS. 31-33 . The wheel 84 of the present invention may be likewise shaped.
[0109] Referring now to FIGS. 6-7 , shown is another embodiment of the present invention. This embodiment having a housing 20 , a tape blade aperture 34 , and a tape terminating in a tape tip 60 . This embodiment having a marking portion holder 120 which is integral with the housing 20 . This is in contrast to a holder which is attached to the housing, as shown in FIG. 1 . These figures show that the holder may either be formed within the housing of a tape measure, or configured for attachment to an existing tape measure. This integral holder 120 rendition is likewise shown in FIGS. 15 and 16 .
[0110] Referring now to FIGS. 8 and 9 , the preferred marking portion 80 comprises a circular wheel 84 . Other shapes and configurations are also possible. It is preferred that the marking portion 80 be made of a rigid material such as metal, plastic or of a mark making composite, however other materials are also possible. The preferred wheel 84 having an aperture 82 for mating with an axle 100 . This axle 100 having axle protrusions or ends 102 configured for rotational engagement with the holder 120 . The wheel 84 being preferably mounted at or near the center or middle 104 of said axle 100 . Rotational engagement upon an axle is preferred but not required of the present invention.
[0111] As seen in FIGS. 8-9 and 31 - 33 , the marking portion 80 may be hardened and/or ground at an angle 86 , similar to a glass cutting wheel. This angle 86 may be configured to provide a narrow, accurate mark or may be configured and sharpened to actually serve as a cutting wheel. Thus, “marking” is intended to include marking by cutting, scribing and/or scoring. Also, the impression wheel 84 preferably has a rim 88 for contacting the surface to be marked, at least a portion of this rim extending out of the enclosure/holder 120 .
[0112] The axle 100 is preferably an elongated cylindrical shape, as shown in FIGS. 8-9 . This axle 100 being preferably made of a rigid material such as metal or plastic. The marking portion 80 of FIG. 8 , having an axle 100 , a middle 104 , and two ends 102 . The axle 100 may be integral to the marking portion 80 or the holder 120 or the housing 20 .
[0113] The holder 120 is preferably an elongated square or a right rectangular parallelepiped shape. The holder 120 having a means of attachment to the housing in one embodiment. Examples of such attachment include adhesives, snap fits, magnets, hook-and-loop fasteners, dove-tail joints, etc. In other embodiments, the holder 120 is integral with the housing, being formed into the housing during or after manufacture. The housing preferably has a protruding cursor 124 that is in alignment with a means for holding a marking wheel parallel to the face of the housing and at a precise position to the bottom of the housing.
[0114] As shown in FIGS. 25-30 , the holder 120 is preferably an elongated square (right rectangular parallelepiped) in shape. Other shapes are also possible. The holder 120 preferably has a cavity 126 for nesting of the marking portion 80 . The holder 120 preferably has a means of attachment 122 to the housing 20 , one example of which is shown in FIG. 24 . The housing 120 preferably has a protruding cursor 124 that is in alignment with a marking wheel of the marking portion 80 . This cursor being generally parallel to the face of the housing 20 and generally perpendicular to the means for measuring 40 .
[0115] As shown in FIGS. 17 and 18 , any means for holding the marking portion 80 perpendicular to the means for measuring 40 in such a way as to allow engagement of the marking portion 80 with the surface to be measured and marked 160 may be utilized as can be appreciated.
[0116] As shown in other embodiments, such as FIGS. 11-14 , the bottom wall 28 or a portion thereof (partially sloped base) 29 may be angled in such a way as to allow for engagement of the tape tip 60 to the surface being measured 160 without initiating contact of the marking portion 80 until it is intended. Although one angle is shown, many angles, combinations of angles, cutaways, or geometric reveals or shapes could achieve the desired results as can be appreciated. The preferred angle is between 7° and 9°. As shown, it is preferred that this angular relationship of the wall 28 to the partially sloped base 29 be configured along the base length of the housing. However, any base shape that allows for the engagement of the tape tip 162 to the end 62 without engaging the mark making means 80 will work and are also envisioned.
[0117] In such a configuration, the marking tape measure comprises a housing 20 for containing a tape and a marking device 80 . This housing 20 having a tape opening or aperture 34 and a top wall or side 26 opposite a bottom wall or side. The bottom side comprising a first longitudinal surface (bottom) 28 obliquely joining a second longitudinal surface (partially sloped base) 29 . The tape having measuring indicia thereon, and being extendible through the tape opening in a first direction. The remainder of the tape being coiled within the housing. The marking device thus being connected to the housing in alignment with the second longitudinal surface, configured to extend out of the housing adjacent the second longitudinal surface.
[0118] In such a manner, a user could hook the tape tip 60 on the edge or end 162 of the surface to be marked and measured 160 . With the housing 20 tilted as shown in FIG. 12 , the housing could be slid away from the end 162 thereby extending the tape out of the housing without engaging the marking portion 80 . When the desired extended length is reached, the user could right the housing 20 as shown in FIG. 11 , thereby allowing the marking portion 80 to engage the surface to be measured and marked.
[0119] As shown in FIGS. 17 and 18 , the housing 20 may have a ramp 36 is flexible when pressure is applied. This ramp 36 prevents the marking of the surface being measured and marked 160 until the user presses downwards on the housing 20 thereby flexing said ramp 36 and allowing the marking portion 80 ( 80 ′) to contact the surface to be marked. It is preferred that this ramp 36 be comprised of a resilient material able to return to its original shape after such pressure is removed.
[0120] Another variation of the housing may include the inclusion of at least one roller or bearing located on the bottom wall of the housing to facilitate perpendicular movement of the housing, to the means for measuring, against the surface to be measured and marked.
[0121] The preferred coiled measuring tape utilized with the present invention is an elongated blade formed of a ribbon of metal or composite material. This blade configured to be coiled on a means for a spool (spool means) with a means to retract (retraction means). This tape measure configuration (spool means with retraction means) is well known in the prior art. As shown in FIGS. 5, 19 , 20 , 22 , and 23 of the drawings, the coiled measuring tape 40 comprises an elongated blade 40 formed of a ribbon of metal or composite material coiled on a means for a spool with a means for retraction. It is clearly anticipated that the coiled ribbon measuring tape 40 may be replaced by other means for measuring including digital, GPS, sonar, laser, magnetic, proximity or any other means for determining distance or position.
[0122] Referring now to FIGS. 15-16 , 42 - 43 , the marking portion 80 may not be a wheel, but may be directional in shape. For instance the elongated point of FIG. 16 or the semi-circular shape of the “wheel” 84 of FIG. 15 ; the semi-ovular shaped “wheel” 184 of FIG. 42 ; and the semi-hexagonal shaped “wheel” 284 of FIG. 43 . In such embodiments, the marking portion 80 would not roll along a surface but be scratched, etched, or scribed across the surface to be marked, either leaving a mark or creating a groove in the surface to be marked. In such an embodiment, the fact that the marking portion is directional in shape, particularly directional generally perpendicular to the length of the base 28 of the housing, the marking portion is able to travel generally only perpendicularly across the surface of the surface to be marked. A point, or a scribe, does not have this ability. Neither does a rectangular pencil lead of a contractor's pencil because the lead (graphite) of the pencil is intended to wear (thereby applying a mark to the surface), thereby removing the ability of such a pencil to be directional in shape. The base 28 itself could have formed therein a directional marking portion, for instance a semi-circular ridge.
[0123] The ability to make a mark upon the surface to be marked which is generally perpendicular to the distance measured is key to the preferred embodiment of this invention. This is preferably achieved through the marking portion being directional so that the marking portion will, in use, only apply a mark to the surface which is generally perpendicular to the distance measured (for instance the length of the tape blade). However, other manners may also be utilized to achieve this goal, including manners of restricting the housing itself to perpendicular movement while using a non-directional marking portion, for instance one or more wheels located in the base of the measuring device.
[0124] As shown in FIG. 18 , a particular embodiment may include two or more marking portion 80 , 80 ′. These marking portion 80 , 80 ′ could be separate, as shown, or could be joined together. These marking portion 80 , 80 ′ are preferably aligned with one another so that side to side movement of the housing 20 will result in a single line marked upon the surface to be marked. Optionally, these marking portion could be slightly staggered so that a differing line style or thickness could be provided.
[0125] Referring back to FIG. 1 , it is preferred that the tape measures incorporating the present invention be configured for inclusion with a means for locking the tape blade 140 . The means for locking the tape blade 140 has a button section 144 that protrudes to the exterior of the housing. This is likewise shown in FIG. 3 . There are many alternate means for locking the tape blade 140 , and considered by themselves, are conventional means known in the art and are therefore not shown in detail in the drawings. The means for locking the tape blade 140 is preferably contained in the housing 20 with a button 144 that protrudes to the exterior of the housing 20 . This means for locking the tape blade 140 configured to engage and lock the tape blade 40 . While the inclusion of the means for locking the tape blade is preferred, its use is not necessary for the operation of the present invention.
[0126] The surface to be measured and marked 160 can be of any shape or size material that would commonly be measured with said measuring device. The surface to be measured and marked 160 may also be a structure or a combination of materials. A typical surface to be measured and marked is a piece of dimensional lumber.
[0127] The housing 20 and all the housing sub-components integrally form an enclosure. The coiled measuring tape 40 is retractably contained inside the housing enclosure 20 on a hub with the free end of the coiled measuring tape 40 extending through the housing aperture, attaching to the tape tip 60 . The tape tip 60 is integral with the free end of the coiled measuring tape 40 .
[0128] In the preferred embodiments, the marking portion 80 mates with the middle 104 of the axle 100 . As such, the axle 100 protrudes from both sides of the marking portion 80 . These axle protrusions 102 are able to be received integrally in the walls of the cavity of the holder 126 . The preferred holder 120 includes a means for attachment 122 to the housing 20 , and is preferably interconnected with the housing 20 . Likewise, the holder may be integral with said housing 20 , as shown in FIG. 6 .
[0129] It is preferred that the holder 120 have a protruding cursor 124 that is integral. This cursor 124 indicating to the user the location of the marking portion 80 to the user. Referring now to FIGS. 5, 10 and 11 , in use the housing 20 may be brought into contact with the surface to be measured and marked 160 . The tape tip 60 is allowed to engage the edge 162 of the surface to be measured and marked 160 , while the housing 20 is pulled across the surface to be measured and marked 160 to the desired location as verified by the cursor 124 . The marking portion 80 is then engaged by altering the angle of the housing 20 , as shown in FIGS. 11 and 12 , and applying downward pressure to the marking portion 80 . Due to the generally perpendicular attitude of the marking portion 80 to the means for measuring 40 , the desired position of the marking portion 80 is maintained. This is due to the nature of the marking portion 80 being directional and configured for moving directionally (side to side) and not forward or backward. This is likewise illustrated in FIGS. 5, 10 , 12 , 15 - 16 , and 19 - 22 .
[0130] Referring now to FIGS. 34 and 35 , shown is an alternative embodiment of the present invention. In this embodiment, a chamber 50 is provided for containing an amount of a liquid, powder or gel (preferably a liquid) marking substance. This chamber or well 50 preferably provided with a closure 54 , such as a lid, for allowing additional quantities of the marking substance to be added to the well. The chamber 50 may be of any size or configuration and may be located inside or outside the housing. It may also be integral with the housing or removable as in a cartridge format.
[0131] This marking substance being transmitted to the marking portion 80 through a channel 52 , preferably via a wick to an applicator 54 for applying the marking substance, such as an ink, paint, chemical, etc., to the wheel of the marking portion 80 . It is preferred that in such an embodiment that a wick be employed to transfer the marking substance with the end of the wick comprising the applicator. The rotation of the marking portion transfers the marking substance to the surface to be marked.
[0132] Referring now to FIG. 36 , in yet another embodiment of the present invention, a marking applicator could be provided for applying a marking substance, such as graphite, charcoal, wax, chalk, ink, paint, etc., to the marking portion 80 . For instance, a pencil lead (graphite) 92 could be held under tension against the surface of the marking portion 80 , particularly the wheel 84 , which contacts the surface to be marked 160 . Thus, rotation of the wheel 84 of the marking portion against the surface to be marked 160 also results in rotation of the wheel 84 of the marking portion against the indicia (marking) applicator 90 . This results in the transmission of the marking substance from the marking applicator 90 onto the wheel 84 of the marking portion. Then, continued movement of the marking portion 80 against the surface to be marked 160 results in the transfer of the marking substance to the surface to be marked from the marking portion. Thus, for instance, utilization of the present invention could result in the creation of an ink line along the directional track of the marking portion.
[0133] Additionally, the marking portion utilized with the marking applicator could comprise or be comprised at least partially of, a rubber material or a porous material allowing for easier application of such a marking substance. Such a rubber or porous material would more easily hold and carry to the surface to be marked the marking substance, for instance chalk.
[0134] Additionally, the marking applicator could be selectively engaged or disengaged by the operator through use of an engagement/disengagement means 70 . This would allow the operator or user of the present invention to decide whether to also or instead apply a marking substance to the surface marked. For instance, a spring mechanism 72 could be utilized whereby through pushing a button 74 on the coiled measuring tape the marking applicator could be activated or deactivated.
[0135] As the wheel is rolled on the surface to be marked, ink another marking material or substance is deposited on the wheel. The wheel, as it rolls, deposits the marking material on to the surface to be marked.
[0136] The housing 20 , the holder 120 , and the marking portion 80 , may be molded, cast or machined as one component, preferably from a rigid material such as metal, plastic or a mark making composite, for instance magnesium.
[0137] Referring now to FIG. 37 , shown is another embodiment of the present invention. This embodiment having an asymmetrical tape tip 60 . This tape tip 60 having one side 64 longer than the other side 68 . In such a manner, utilization of the present invention is easier, in that the housing 20 can be tilted as shown in the figure with the tape hook 60 one side 64 , being elongated, more easily engaging the end 162 of the surface to be marked and measured 160 , thereby allowing the device to be utilized without engaging the marking device 80 .
[0138] Referring now to FIGS. 38-40 , shown is another embodiment of the present invention. This embodiment comprising a tape case housing 20 having integrally built therein a directional marking portion 80 . This directional marking portion 80 comprising a marking portion 284 extending downwards there from configured for marking a surface to be marked. The preferred location for such a marking portion 284 being the bottom wall or base 28 of the housing 20 . Other locations are likewise envisioned.
[0139] The major benefits to such an embodiment including the fact that there are no additional moving parts involved in the marking portion and therefore less of a chance of failure or wear, and because the portion can be a part of the case itself, there is little, if any, additional manufacturing cost in that no additional assembly, labor or mold charges are required.
[0140] In the embodiment shown, this marking portion 284 comprises a curved extension away from the bottom wall 28 of the tape case housing 20 . More specifically, the embodiment showing a pair of forwardly extending flanges 280 , 281 extending from the front wall 32 with the marking portion 284 extending downwards from these flanges away from the bottom wall 28 . The marking portion 284 in alignment with cursor(s) 224 . Thus, in said embodiment, the marking portion 284 preferably extends either downwards from the bottom wall or below the plane of at least a portion of the bottom wall 28 . Additionally, the marking portion could be above said plane, requiring the user to tilt the tape case in use.
[0141] The marking portion can comprise anything from a ridge, ledge, rim, knob, protrusion(s), lip, overhang, etc., extending from the housing 20 . The preferred shape of the portion being generally crescent shaped, this crescent shape permitting directional movement of the marking portion. This crescent shape preferably generally convex and integral to the tape case. However, other shapes are also envisioned.
[0142] It is preferred that the directional marking portion 80 be comprised of a material which is configured for marking. Such a material can include plastics, metals and ceramics. A preferred material is magnesium or a magnesium alloy. It is foreseen that the entire tape case, including the marking portion can be made of such a marking material (thereby being comprised of the same material as the tape case), or in other embodiments, just the marking portion being made of the marking material.
[0143] It is preferred that the housing 20 shown having a cursor(s) 224 extending from and adjacent to the marking portion 284 . This cursor(s) for allowing a user to visually determine the location at which the present invention will mark the surface to be marked.
[0144] While it is preferred that the marking portion be an integral part of the housing, optionally, the portion could be removable and replaceable so that when and if the portion becomes worn and/or consumed, the user could recondition the tape measure by replacing the portion. Such an embodiment is shown in FIG. 41 . Such a replaceable portion 284 being fastened to the housing through use of a fastener(s) 291 . This fastener(s) 291 preferably extending through a mounting hole(s) 292 located in the marking portion 284 . Likewise, other fasteners or means of fastening may be used to attach the replaceable portion 284 to the housing, including but not limited to fasteners, adhesives, welds, friction fits, snap fits, hook-and-loop, etc.
[0145] Referring now to FIGS. 44-47 , shown are two embodiments of a “pen-style” directional marker(s) of the present invention. This embodiment having what is referred to as a “pen-style” directional marker 380 . The term “pen-style” is used to indicate any applicator of a liquid or gel marking substance 111 to the wheel(s) 484 , including but not limited to the specific embodiment described herein. Non-exclusive examples of suitable marking substances for this embodiment include, but are not limited to: inks, paints, dyes, liquid graphite, colored liquid materials appropriate for any and all trade applications, visible ink, “invisible” ink, disappearing ink, permanent inks, erasable inks, etc. It is preferred that the marking substance be interchangeable, refillable and/or replaceable. This directional marker (as with all of the other embodiments of the present invention) could be integral to the tape case or could be a separate component which is configured for attachment to the tape case or other structure/location.
[0146] The wheel is preferably configured to, after application of the marking indicia/substance to the wheel, subsequently rotationally transfer the marking indicia to the surface to be marked thereby creating at least one mark. It is preferred that the wheel be generally circular and disposed generally perpendicular to the first direction (the direction the tape measure's blade extends). The wheel having a circumference defining a rim, this rim having a width, wherein said rim width is generally perpendicular to the rotation of the wheel.
[0147] The marking device/directional marker 380 attaching preferably to the front of a tape measure 10 case. Such a tape measure having a tape blade 40 extendable there from. The preferred embodiment utilizing a “ball-point pen” style applicator 90 for applying the marking substance 111 to the wheel 484 . The applicator 90 having a reservoir 112 for holding a supply of the marking substance. The marking substance within the applicator 90 is preferably interchangeable, refillable and/or replaceable. For that reason, in this embodiment a cap 114 is provided for allowing the applicator 90 to be removed. A spring device 113 may be present for biasing the applicator against the wheel or this may be achieved through other means. Some such spring biased applicators may be “clicked” or otherwise configured to be selectively engaged/disengaged against the wheel.
[0148] As can be seen particularly in the close-up view of FIG. 46 , the applicator 90 having a spherical ball 285 . In this embodiment, the applicator is a traditional “ball-point pen” style applicator as is known in the art. However, other types of applicators are also envisioned for applying the marking substance to the wheel. A benefit to this style marking device is the fact that as long as the wheel is not revolving, the marking substance is held separate of the external portion of the tape measure and therefore the marking substance will not leak or otherwise be transferred out of the marker. This prevents stray marks and the mess often associated with such devices. An ideal ball-point pen comprising a spherical writing ball rotationally disposed in and partially exposed from a pen tip, this ball in fluid communication with a marking indicia reservoir.
[0149] The wheel 484 is preferably, but not necessarily, disposed on an axle 116 and configured to engage the ball 285 via a circumvolving groove or channel 485 within the rim of said wheel. This groove facilitating the rolling of the wheel along the wheel face, thereby assisting in the transfer of the marking substance to the wheel face/rim for application to the surface to be measured and marked. This groove is preferably “V-shaped,” however other configurations are also possible, including but not limited to U-shaped, W-shaped, etc. Additionally, no such channel may be present in some embodiments of the present invention. Instead, the ball would merely roll against the wheel face, applying the marking substance directly thereon. In such an instance, the wheel face may contain abrasions, cuts, indentions, pits, holes, etc. for assisting the wheel in obtaining marking substance from the pen and for carrying the marking substance to the surface to be measured and marked.
[0150] In an additional embodiment, a portion of the wheel itself could travel a portion of the pen configured for storing the marking indicia, thereby applying the marking indicia/substance to the wheel without using a spherical ball. In another embodiment, the spherical ball (omni-directional) with a roller (directional) or other directional means. Such a directional roller could be used in lieu of a wheel.
[0151] Referring now to FIGS. 48-50 , shown is another embodiment of the present invention. In this embodiment, the marking device (marking indicia applicator) applies a solid marking substance to the wheel. In one such embodiment, applicator is similar to a mechanical pencil, dispensing a graphite solid marking substance. Other types and configurations of applicators are envisioned, the term “mechanical pencil” not intended to be exclusive to mechanical pencil mechanisms, but intended to include any solid marking substance dispenser. Other types of solid marking substances are also envisioned, including but not limited to graphite, crayon, colored pencil, wax pencil, lead, inks, dyes, etc. The term “solid” intended to include both solid and semi-solid substances.
[0152] In one embodiment, the marking device is merely biasing a solid/semi-solid stick of marking substance against the wheel, the marking substance thus applied to the wheel, the wheel then rotationally transferring the marking substance to the surface to be measured and marked as a line.
[0153] In the embodiment shown in FIGS. 48-50 , the applicator 580 is configured for applying a solid marking substance 121 to the wheel 117 . In the embodiment shown, the applicator has a marking housing 119 therein. This marking housing 119 for aligning the solid marking substance 121 with the wheel 117 . This marking housing preferably containing a passageway there through for the marking substance to pass. The marking housing further configured, at its lower end, for mating with the wheel 117 via a notch 127 formed therein (as specifically shown in FIG. 50 ). In such a manner, the marking substance 121 is effectively applied to the rim of the wheel.
[0154] A channel 581 for receiving therein the components of the applicator 580 is preferably defined within the applicator housing. When installed, inserted into this channel (as shown in FIG. 48 ) is the marking housing 119 , the solid marking substance 121 , a spring 123 for biasing (holding in frictional engagement) the marking substance against the wheel, and a cap/spring housing 125 for holding the marking substance in engagement with the wheel via the spring. While this is the preferred embodiment, obviously other embodiments are envisioned and are included within this disclosure. Likewise in this embodiment, as long as the wheel is not rolled, the marking substance will not leak out of the housing or erroneously be applied to a surface.
[0155] With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
[0156] Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
[0157] While there is shown and described the present preferred embodiment of the invention, it is to be distinctly understood that this invention is not limited thereto but may be variously embodied to practice within the scope of the following claims. From the foregoing description, it will be apparent that various changes may be made without departing from the spirit and scope of the invention as defined by the following claims.
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A tape measure that incorporates a marking device for allowing an individual to measure and mark a wide variety of materials in a more efficient and economical manner, and for measuring and marking the beginning point of reference and the measured position point simultaneously. The tape measure has a housing, a coiled measuring tape, a tape tip, and a marker having a marking wheel mounted on an axle.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to gain control circuits and is more particularly directed to a gain control circuit of the voltage-control type, wherein the gain thereof varies as an exponential function of a control voltage applied thereto.
2. Description of the Prior Art
Conventional gain control circuits for electrically controlling the circuit gain use small signal impedance changes to provide corresponding changes of bias voltage or current for non-linear elements, such as semiconductor diodes, bipolar transistors, or field-effect transistors. However, the control characteristics and input/output characteristics of these circuits are far less than is desirable for high fidelity audio equipment, and such circuits are generally unsuitable for use in an audio-signal noise-reduction circuit.
A voltage-control type gain control circuit having a higher performance characteristic has been proposed, for example, in U.S. Pat. No. 3,714,462 to David E. Blackmer. Such circuit takes advantage of the well-known exponential voltage-to-current characteristic of the base-emitter junction of a bipolar transistor. The circuit includes a log-converting transistor and an antilog-converting transistor. Unfortunately, the total static current flowing through these transistors varies greatly as a gain control signal applied thereto is varied, as will be described hereinafter in greater detail.
Because of the significant variations of the static current of such a circuit, a high static current is accompanied by adverse effects such as increased feed-through of the control signal, increased noise (mainly shot noise), and increased current consumption. Conversely, low static current is accompanied with such problems as the generation of crossover distortion. This occurs because of the reduction of the mutual conductance of transistor in the neighborhood of the zero crossing of the input current. Another adverse effect of low static current is the generation of non-linear distortion. This occurs because the operation of the feedback path and output path formed by the PNP and NPN complementarily conductive transistors approach class B operation when the collector-emitter current is low. Still further problems accompanying low static current are the restriction of bandwidth due to the reduction of the cut-off frequency of the transistors, and the instability of the bias circuit with respect to temperature and to source voltage fluctuations.
The actual static current in the prior art voltage-control type gain control circuit is thus selected as a compromise, or trade-off of the aforementioned opposite high- and low-static-current conditions. However, as aforesaid, the variations of the static current with changes of the gain are rather great. Consequently, the available range of selection mentioned above is unavoidably kept narrow. Furthermore, the aforementioned adverse effects cannot be avoided altogether, because of the wide fluctuations in static current that can occur.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide an improved gain control circuit capable of avoiding the above-mentioned defects of conventional circuits.
A more specific object of this invention is to provide a gain control circuit of the voltage-circuit type, in which the total static current is held at a constant value irrespective of any changed in the gain thereof as determined by a gain control voltage.
Consequently, it is a further object of this invention to provide a voltage-control type gain control circuit, in which the transistor cut-off frequency is reduced, thus increasing frequency response range, and reducing feed-through (i.e., leakage of the control signal) and noise (particularly shot noise), while achieving satisfactory linearity in the gain control characteristics and input/output characteristics thereof.
A still further object of the present invention is to provide a voltage-control type gain control circuit suitable for integration as a semiconductor integrated circuit and which is economically realizable on a small circuit scale by omitting an operational amplifier.
A yet further object of the present invention is to provide a voltage-control type gain control circuit having a low transistor cut-off frequency and a broad bandwidth frequency characteristic.
Another frequency object of the present invention is to provide a gain control circuit having a wide gain control range and a satisfactory linearity over that control range.
A yet still further object of the present invention is to provide a gain control circuit having a satisfactory linear input/output characteristic, while being substantially free of significant distortion.
Another further object of the presdent invention is to provide a gain control circuit which avoids feed-through of the control signals.
A yet still further object of the present invention is to provide a gain control circuit in which noise, particularly shot noise, is substantially reduced.
In accordance with an aspect of the present invention, a gain control circuit of voltage control type comprises an input stage for receiving an input signal; a first differential amplifier having an input coupled to the input stage and first and second differential output terminals; a second differential amplifier having an input coupled to the input stage and first and second differential output terminals; a first pair of transistors of one conductivity type having emitters coupled together to the first differential output terminal of said first differential amplifier, and having respective bases and collectors; a second pair of transistors having an opposite conductivity type to that of the first pair, having emitters coupled together to the first differential output terminal of said second differential amplifier, and having collectors coupled so that the collector of one transistor of the first pair is coupled to the collector of one transistor of the second pair, and the collector of the other transistor of the first pair is coupled to the collector of the other transistor of the second pair, and having respective bases, the base of the one transistor in each pair being joined to the base of the other transistor of the remaining pair; a feedback circuit coupling the collectors of the one transistors to the input stage; a circuit joining the second differential output terminals of the first and second differential amplifiers to each other and to a common point; and an output circuit coupled to the collectors of the other transistors of the first and second pairs. Preferably, the differential amplifiers each include two transistors of the same conductivity type as that of the associated pair of transistors. In such arrangement the emitters thereof are coupled together to a constant current source, and the collectors of these transistors respectively provide the first and second differential output terminals. The bases thereof are connected to the input stage and to a reference point. The input stage can include an operational amplifier, which can be followed by a linearizing resistor.
The above and other objects, features, and advantages of the present invention will become readily apparent from the ensuing detailed description of illustrative embodiments of the invention, to be read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit diagram showing a prior-art gain control circuit;
FIG. 2 is a graph showing the static current characteristics of the circuit of FIG. 1;
FIG. 3 is a circuit diagram showing a first embodiment of the present invention;
FIG. 4 is a graph showing the static current characteristics of the embodiment of FIG. 3;
FIG. 5 is a circuit diagram showing a second embodiment of the present invention;
FIG. 6 is a circuit diagram showing a third embodiment of the present invention;
FIG. 7 is a circuit diagram showing a fourth embodiment of the present invention;
FIG. 8 is a circuit diagram showing a fifth embodiment of the present invention;
FIG. 9 is a circuit diagram showing a sixth embodiment of the present invention; and
FIG. 10 is a circuit diagram showing a seventh embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference initially to FIG. 1 of the accompanying drawings, a conventional gain control circuit will be described in detail for the purpose of emphasizing the advantageous features of this invention.
The conventional circuit, which is of the voltage-control type, has a logarithmic input/output characteristic, and is used as a variable-gain element in a noise-reduction circuit, for example, for use in the recording and playback of magnetic tapes or in the playing of audio records. An explanation of such noise reduction is contained, for example, in U.S. Pat. No. 3,789,143 to David E. Blackmer.
As shown in FIG. 1, the conventional gain control circuit includes an input signal source 1, here shown as a current source, coupled to an inverting input of an operational amplifier 2, whose non-inverting input is grounded. An NPN feedback transistor 3 and a PNP feedback transistor 4 have their collectors coupled to the inverting input terminal of the operational amplifier 2, and have their emitters respectively coupled through a negative bias voltage source 5 and a positive bias voltage source 6 to the output terminal of the operational amplifier 2. The transistors 3 and 4 provide a feedback current to the operational amplifier 2, which thereby acts as an error amplifier.
This conventional gain control circuit further includes an NPN output transistor 7 and a PNP output transistor 8. The emitters of the transistors 7 and 8 are respectively coupled to the emitters of the transistors 3 and 4. The collectors of the transistors 7 and 8 are joined together to one end of an output load resistor 9, whose other end is grounded. First and second control signal inputs 10a and 10b are respectively coupled to the bases of the transistors 3 and 8 and to the bases of the transistors 4 and 7. In this circuit a balanced control voltage V C is applied between the two control signal inputs 10a and 10b, so that a control voltage (-Vc/2) is applied to the bases of the transistors 3 and 8, while a complementary control voltage (+Vc/2) is applied to the bases of the transistors 4 and 7.
In the conventional gain control circuit of FIG. 1, the signal source 1 provides an input signal current i in , and a resulting output current i out flows in the load resistor 9. Also, currents i 1 , i 2 , i 3 , and i 4 flow through the collectors of the respective transistors 3, 4, 7, and 8. For any particular input signal current i in , the operational amplifier 2 provides at its ouput terminal a voltage v 1 . Each of the bias voltage sources 5 and 6 provides a bias voltage difference V B .
If the base-emitter saturation current through each of the transistors 3, 4, 7, and 9 (being the same for each of the transistors) is expressed as I S , and the unit electron charge, Boltzamnn's constant, and the absolute Kelvin temperature of the base-emitter junction are expressed as q, k, and T, respectively, the collector currents i 1 , i 2 , i 3 , and i 4 can be expressed as follows: ##EQU1## At normal temperature (T=300° K.) the expression kT/q is approximately equal to 26 mV.
Thus, the input current i in can be expressed ##EQU2##
Likewise, the output current i out can be expressed ##EQU3##
Thus, the relation between input and output currents can be expressed ##EQU4##
Consequently, the current gain of the conventional circuit of FIG. 1 varies as an exponential function of the control voltage V C .
However, as will now be explained, in the circuit of FIG. 1, the static current, also called the idling current, which flows through the transistors 3, 4, 7, and 8 when there is no input signal (i.e., when i in =0) varies significantly in amplitude as the gain control voltage V C is varied. In FIG. 1, and in the chart of FIG. 2, the static current through the feedback transistors 3 and 4 is represented by ID in while the static current through the output transistors 7 and 8 is represented by ID out . The variation of the static currents ID in and ID out with the gain conrol voltage V C has adverse effects upon the characteristic of the conventional gain control circuit, as will be apparent from the following discussion.
When the input signal i in is zero, and, therefore, the output current i out is also zero, the static current ID in through the feedback path and the static current ID out through the output path can be respectively expressed as
ID.sub.in =i.sub.1 =-i.sub.2 ;
and
ID.sub.out =i.sub.3 =-i.sub.4.
Consequently, ##EQU5##
The foregoing expressions can be shortened by using the symbols I 0 and A defined as
I.sub.0 ≡I.sub.S exp (qV.sub.B /kT)
and
A≡exp (qV.sub.C /kT).
Here, A should be recognized as the current gain as shown in the equation (7). Thus, the expressions (8) and (9) can be rewritten as
ID.sub.in =I.sub.0 ·A.sup.-1/2 . . . (10)
and
ID.sub.out =I.sub.0 ·A.sup.+1/2 . . . (11)
Accordingly, the static current ID in and ID out through the feedback path and the output path respectively vary as a function of gain as shown in the solid line in FIG. 2. Accordingly, the sum of the static currents ID in +ID out , as represented by the dashed curve in FIG. 2 will vary from a value of 2I O to a value of approximately 50 I O . In other words, the ratio of the maximum value of the sum ID in +ID out to the minimum value thereof is about 17 dB. Furthermore, the gain control circuit of the type shown in FIG. 1 has the disadvantage of unacceptably high-feed through of the control signal and an increased noise figure (mainly due to shot noise), and increased power consumption whenever the static current is high. Conversely, when the static current is low, the gain control circuit of FIG. 1 is subject to such problems as crossover distortion due to the reduction of mutual conductance of the transistors 3, 4, 7, and 8 at the neighborhood of the zero crossings of the input current i in . Additionally, when the static current is low, non-linear distortion can occur because the feedback and output paths formed by the PNP and NPN complementary transistors 3, 4, 7, and 8 approximate class B operation. Moreover, when the static current is low, the cutoff frequency of the transistors 3, 4, 7, and 8 is reduced and the bias circuit 5, 6 becomes unstable because of temperature and source voltage fluctuations, with the result that the bandwidth of the circuit of FIG. 1 is reduced.
Consequently, the actual static current selected for the circuit of FIG. 1 is a compromise between the aforementioned extreme conditions. However, because the variations of the static current with gain are so large, as shown in FIG. 2, the range of appropriate values for the static current is rather narrow.
Furthermore, the aforementioned problems cannot be avoided when the static current is caused to vary because of changes in gain.
The present invention seeks to avoid the aforegoing problems, and instead provide a voltage control type gain control circuit in which the total static current is maintained substantially at a constant level regardless of any change in the gain of the circuit caused by the applied gain control voltage V c .
A first preferred embodiment of this invention is shown in FIG. 3. As illustrated in that view, an input signal source 11, here shown as a current source, is coupled to an inverting input terminal of an operational amplifier 12, which is here configured as an error signal amplifier, and has its non-inverting input terminal grounded. The output terminal of the operational amplifier 12 is coupled through bias sources 13 and 14 to respective inputs of first and second differential amplifiers 21 and 22. Constant current sources 15 and 16 are respectively coupled to the differential amplifiers 21 and 22, and bias sources 17 and 18 are respectively coupled to control terminals thereof.
A load resistor 19 absorbs the output signal current I out therefrom.
The first differential amplifier 21 is formed of PNP transitors 23 and 24, whose emitters are commonly connected to the current source 15, and whose bases are respectively coupled to the bias sources 13 and 17. Similarly, the second differential amplifier is formed of a pair of NPN transistors 25 and 26 whose emitters are commonly coupled to the current source 16 and whose bases are respectively coupled to the bias sources 14 and 18. The collectors of the transistors 23 and 25 are grounded.
The bias sources 13, 14, 17, and 18 apply bias voltages +V B to the bases of the PNP transistors 23 and 24 and bias voltages -V B to the bases of the NPN transistors 25 and 26.
Further in the circuit of this invention is a first pair of transistors formed of a PNP feedback transistor 33 and a PNP output transistor 34, and a second pair of transistors formed of an NPN feedback transistor 35 and an NPN output transistor 36. The emitters of the transistors 33 and 34 are joined to each other and to the collector of a transistor 24 of the first differential amplifier 21. Similarly, the emitters of the transistors 35 and 36 of the second pair 32 are joined to each other and to the collector of the transistor 26 of the second differential amplifier 22.
The collectors of the feedback transistors 33 and 35 are joined together and are coupled through a feedback conductor 37 to the inverting input of the operational amplifier 12. The collectors of the output transistors 34 and 26 are joined together to the output load resistor 19. A pair of control signal inputs 38 and 39 are also provided with the input 38 coupled to the base of the output transistor 34 of the first pair 31 and to the base of the feedback transistor 35 of the second pair 32, and with the input 39 coupled to the base of the feedback transistor 33 of the first pair 31 and to the base of the output transistor 36 of the second pair 32.
In the voltage-control type gain control circuit as illustrated in FIG. 3, the output transistors 34 and 36 have respective collector-emitter currents i 1 and i 2 , while the feedback transistors 33 and 35 have respective collector-emitter current i 3 and i 4 . The transistors 24 and 26 have collector-emitter currents i 5 and i 6 , while the transistors 23 and 25 have respective collector-emitter currents i 7 and i 8 . The voltages at the emitters of the first and second pairs of transistors 31 and 32 are respectively expressed v 1 and v 2 , while the voltage at the emitters of the transistors 23, 24 of the first differential amplifier and at the emitters of the transistors 25 and 26 of the second differential amplifier 22 are respectively expressed as v 3 and v 4 . The voltage at the collectors of the transistors 23 and 25 (i.e., ground voltage) is expressed as v 5 . The bias sources 13, 14, 17, and 18 each supply a bias voltage V 8 .
Accordingly, the input current from the input signal source 11 can be expressed
i.sub.in =i.sub.4 -i.sub.3 . . . (12)
while the output current i out through the resistor 19 is expressed
i.sub.out =i.sub.1 -i.sub.2 . . . (13)
Further, the current i 5 flowing through the transistor 24 of the first differential amplifier 21 to the first transistor pair 31 is expressed
i.sub.5 =i.sub.1 +i.sub.3 . . . (14)
Likewise, the current i 6 flowing from the second transistor pair 32 and thence through the transistor 26 of the second differential amplifier 22 can be expressed
i.sub.6 =i.sub.2 +i.sub.4 . . . (15)
The saturation current through the transistors 24, 26, 33, 34, 35, and 36 are all equal to I S , with the saturation current through the transistors 23 and 25 being set to a multiple thereof, KI S (where K is a constant). Here, the grounded-base current amplification factor α of all of the transistors 23, 24, 25, 26, 33, 34, 35, and 36 is assumed to be unity.
The output transistor 34 and the feedback transistor 35 of the first and second transistor pairs 31 and 32 can be assumed to be grounded, so that the gain control voltage V C is applied entirely to the bases of the feedback transistor 33 and output transistor 36. Consequently, the aforementioned currents i 1 -i 4 can be expressed as follows: ##EQU6## Where V T =kT/q.
Substituting the equations (14) and (15) into the equations (16) to (19) yields ##EQU7## Consequently, ##EQU8## Furthermore, ##EQU9## and, consequently, ##EQU10## Substituting the equations (20) and (22) into the equations (16) to (19) yields ##EQU11## Here, the factor A=exp (V C /V T ).
As a result, the net circuit gain G, equal to the ratio of the output current i out to the input current i in , can be obtained by the substitution of the equation (24) to (27) into the equations (12) and (13) to yield ##EQU12## As is apparent from the foregoing the net current gain is an exponential function of the control voltage V C . When there is a zero input signal, that is, when the input current i in =0, the static idling current ID in flowing from the transistor 33 into the transistor 35 can be expressed ID in =i 3 =i 4 . Consequently, the static current ID in can be expressed either by equation (26) or by equation (27). If the expressions i 5 +2I S =i 6 +2I S =I T during the absence of any input signal i in , the static current ID in can be expressed ##EQU13## Further, at the time of the absense of any input signal, the output current i out is also equal to zero, and the static current ID out flowing from the transistor 34 into the transistor 36 can be expressed ID out =i 1 =i 2 , so that the equations (24) and (25) can be rewritten as ##EQU14##
As is apparent, the sum of the equations (29) and (30) is a constant. That is, the sum of the static currents ID in +ID out will have a constant value I T regardless of any change of the current gain A.
As is shown in FIG. 4, where the static current ID in and ID out are represented with solid lines and the sum thereof is shown by a dashed line, the total static current I T has a flat plot with respect to changes in gain A. Normally, as the saturation current I S has a small value, the total static current I T is substantially equal to the collector current i 5 or i 6 . Consequently, the total static current I T can be roughly expressed as a function of the current I O supplied from the constant current sources 15 and 16 to the first and second differential amplifiers 21 and 22, and as a function of the saturation current ratio K of the various component transistors: ##EQU15## The value of the current I O from the constant current sources 15 and 16 is selected in accordance with the maximum values of the input current i in and the output current i out . Consequently, the total static current I T is determined by the selection of the saturation current ratio K.
Because, in the voltage control type gain control circuit of this invention, the static current is held constant regardless of the gain A, it is possible to select the optimum static current which will avoid any of the above mentioned drawbacks which occur when the static current is selected too high or too low. Thus, it is possible to achieve a wide-band frequency characteristic by minimizing the reduction of the cut-off frequency of any of the transistors. It is also possible to increase the control range of the circuit with satisfactory linearity of the control characteristic, and thereby to reduce any distortion in the linearity of the input/output characteristic thereof. Furthermore, the gain control circuit of this invention reduces any feed-through of the control voltage signal V C , minimizes any shot noise or other random noise, and suppresses the generation of crossover distortion in the vicinity of the zero crossings of the input signal i in . Additionally, the total static current I T can be selected sufficiently high so that the voltage sources 15 and 16 will provide a reliable steady current and the bias sources 13, 14, 17, and 18 will provide reliable steady bias voltages regardless of temperature and source voltage fluctuations.
FIG. 5 shows a second embodiment of the gain control circuit of this invention. This embodiment is, in fact, a practical version of the embodiment of FIG. 3. In FIG. 5, elements and parts in common with corresponding elements of FIG. 3 are identified with the same reference numbers, and a detailed description thereof is omitted.
In the second embodiment, the bias sources 13 and 14 are replaced by a series circuit formed of current sources 51 and 52, a PNP transistor 53, and an NPN transistor 54. The emitter of the transistor 53 is connected to the current source 51 and also to the base of the transistor 23 of the differential amplifier 21. Similarly, the emitter of the transistor 54 is connected to the current source 52 and to the base of the transistor 25 of the differential amplifier 22. The collectors of the transistors 53 and 54 are each connected to ground, and the bases of the transistors 53 and 54 are each connected to the output terminal of the operational amplifier 12.
The bias sources 17 and 18 are replaced by a series circuit formed of current sources 55 and 56, a PNP transistor 57 and NPN transistor 58. Here the transistors 57 and 58 are connected in a diodic arrangement, with their collectors and bases each connected to ground. The emitter of the transistor 57 is connected to the current source 55 and to the base of the transistor 24 of the first differential amplifier 21. Similarly, the emitter of the transistor 58 is connected to the current source 56 and to the base of the transistor 26 of the second differential amplifier 22.
It will be understood that the transistors 53 and 54 will provide a substantially constant voltage difference between their respective emitters and bases. Similarly, the diodic transistors 57 and 58 will also provide a substantially constant voltage difference between their respective emitters and ground.
The method of establishing the static current I T in the embodiment of FIG. 5 can be explained as follows.
As in the previous embodiment of FIG. 3, the constant K for establishing the static current I T has been defined to be the saturation current ratio of the transistors 34 and 36 to the transistors 24 and 26 of the first and second differential amplifiers 21 and 22. Thus, the voltages of the bias voltage sources 13, 14, 17, and 19 of FIG. 3 are assumed to be identical. The value of K actually attained in the equation (31) normally ranges from unity to several dozens, and is actually determined by any of several conditions which can affect the biasing of the transistors 24, 26, 34, and 36.
However, it is also possible to establish the value of K in a range of one to five by selection of the saturation current ratio of the transistor 34 and 36 to the transistors 24 and 26. In a practical integrated circuit, K is determined by the ratio of the effective emitter areas. However, when K exceeds about ten, the simple saturation current ratio alone requires excessive transistor area, thus increasing the chip area required for the integrated circuit. This problem can be resolved by providing an offset voltage between the bias voltage sources 13 and 14 and between the sources 17 and 18. In the embodiment of FIG. 5, this is achieved by the use of the transistors 53, 54, 57, and 58.
More particularly, the emitter current density of the transistors 53 and 54, which are coupled between the bases of the transistors 23 and 25, is set to be lower than the emitter current density of the transistors 55 and 58, which are connected to the bases of the other transistors 24 and 26. For this reason, the saturation current of the transistors 53 and 54 can be set relatively high as compared to that of the transistors 57 and 58. Alternatively, the current of the constant current sources 55 and 56 can be set higher than that of the constant currents sources 51 and 52.
The constant K in the equation (31) corresponds to the current distribution ratio of the transistors 23 and 25 in the first and second differential amplifiers 21 and 22 to the other transistors 24 and 26 of the differential amplifiers 21 and 22. If the saturation current ratio of the transistors 23 and 25 to the other transistors 24 and 26 is denoted as a constant K 1 , while the saturation current ratio of the transistors 57 and 58 to the transistors 53 and 54 is denoted as another constant K 2 , and the current ratio of the constant current sources 55 and 56 to the constant current sources 51 and 52 is denoted as yet another constant K 3 , the current distribution ratio, denoted as K 0 , can be substantially established as
K.sub.0 =K.sub.1 ·K.sub.2 ·K.sub.3 (32)
As the current distribution ratio K 0 is a product of three factors, it is possible to attain a ratio K 0 of the order of one hundred by setting the individual factors thereof K 1 , K 2 , and K 3 at values of five or less.
The remaining construction of the second embodiment is substantially the same as that of the first embodiment shown in FIG. 3.
As a consequence of the above defined construction, the second embodiment not only permits the results of the first embodiment to be achieved, but also provides circuit construction well suited for implementation as a semiconductor integrated circuit, as steady bias voltage sources are realized without great difficulty by using the voltage drops across the PN junctions of the transistor 53, 54, 57, and 58.
FIG. 6 illustrates a third embodiment of the gain control circuit of this invention. In the third embodiment, elements which are common to the previous embodiments are identified with the same reference numerals, and a detailed description thereof is omitted.
In the third embodiment, the non-inverting input terminal of the operational amplifier 12 is coupled to the signal source 11 and to the feedback conductor 37, while the inverting input thereof is coupled to ground. Also, unlike the foregoing embodiments, the emitters of the first pair of transistors 31 are connected to the collector of the transistor 23 and the emitters of the second pair of transistors 32 are connected to the collector of the transistor 25. The collectors of the transistors 24 and 26 of the first and second differential amplifiers are connected to ground. In this embodiment, as in that of FIG. 5, it is possible to use the base emitter voltages of transistors in lieu of the bias voltage sources 13, 14, 17, and 18.
FIG. 7 illustrates a fourth embodiment of this invention. In FIG. 7, elements in common with the embodiment of FIG. 5 are identified with the same reference numerals, and a detailed description thereof is omitted. In this embodiment, a resistor 59 is included between the output terminal of the operational amplifier 12 and the bases of the transistor 53 and 54. Also in this embodiment, the collectors of the transistors 23 and 24 of the first and second differential amplifiers 21 and 22 are connected to the resistor 59, rather than to ground. Thus, here the collector current of the transistors 23 and 25 is fed back to the transistors 53 and 55 which serve as the input side bias voltage sources for the first and second differential amplifiers 21 and 22. The resistor 59 and the connection of the collectors of the transistors 23 and 25 to the bases of the transistors 53 and 54 ensures that the transfer characteristic at the output terminal of the operational amplifier 12 is linearized. Thus, the output voltage of the operational amplifier 12 will vary linearly with the input current applied from the input source 11. Of course, the previous embodiments, such as the third embodiment (FIG. 6), could be similarly adapted.
FIG. 8 illustrates a fifth embodiment of the gain control circuit of this invention. FIG. 8 particularly shows a specific circuit construction of a circuit of this invention well suited for integration as semiconductor integrated circuit. In FIG. 8, elements in common with the embodiment of FIG. 7 are identified with the same reference numerals, and a detailed description thereof is omitted.
In this embodiment, multi-emitter transistors are used as the transistor 23 and 25 of the first and second differential amplifiers 21 ans 22, so that the current distribution ratio is established by making the saturation current of the transistors 23 and 25 higher than that of the other transistors 24 and 26. For example, with four-emitter transistors, as shown, for transistors 23 and 25, the saturation current through the transistors 23 and 25 is substantially four times that through the single-emitter transistors 24 and 26. Thus, the constant K 1 of the equation (32) is set at 4. Also in this embodiment, four-emitter transistors are used as the transistors 53 and 54 which serve as the base bias voltage sources for the transistors 23 and 25. Therefore, the constant K 2 of the equation (32) is also set at 4. Further, in this embodiment the constant K 3 of equation (32) is set at 2 by establishing the emitter current through the transistors 53 and 54 to be one half that passing through the transistors 57 and 58. This is achieved by using multi-emitter transistors as constant current sources, for example, in the construction shown in FIG. 8 which will now be discussed.
In FIG. 8, transistors 61 and 62 provide current sources for the transistors 53 and 54, respectively. The transistors 61 and 62 have their emitters respectively coupled to a positive voltage V CC and to a negative voltage V EE and have their collectors coupled to the emitters of the transistors 53 and 54. Similarly, two-emitter transistors 63 and 64 extend between the voltage sources V CC , V EE and the emitters of the transistors 57 and 58, respectively. Four-emitter transistors 65 and 66 extend between the voltage sources V CC , V EE and the emitters of the transistors 23 and 25, respectively. A series circuit formed of diode-arranged transistors 67 and 68 whose collectors are coupled by a series resistor 69 provide bias voltages to the transistors 61, 63, and 65 and to the transistors 62, 64, and 66. As can be readily understood from the foregoing discussion, the emitter current through the transistors 57 and 58 is twice that through the transistors 53 and 54 because the transistors 63 and 64 have twice the emitter area as the transistors 61 and 62.
As a consequence, in the fifth embodiment, the constant K 0 of equation (32) is established substantially at thirty-two. Here, the four-emitter transistors 65 and 66, which serve as current source and current sink for the emitters of the first and second differential amplifiers 21 and 22, are provided to furnish a greater amount of collector current to the differential amplifiers 21 and 22.
Also in this embodiment, a current-to-voltage converter is coupled to the collectors of the output transistors 34 and 36. The current-to-voltage converter includes an operational amplifier 70 having a ground non-inverting input terminal, and inverting input terminal coupled to the collectors of the transistors 34 and 36, and an output terminal connected to a circuit output 71. A feedback resistor 72 is connected between the output terminal of the operational amplifier 70 and the inverting input terminal thereof.
While in this embodiment four-emitter transistors 23, 25, 53, 54, 65, and 66 and two-emitter transistors 63 and 64 are used, it is also possible to use multi-emitter transistors arranged in various other configurations to establish a desired value of the constant K 0 .
FIGS. 9 and 10 show further embodiments of this invention, in which the operational amplifier 12, as used in the first through fifth embodiment, is omitted.
In the sixth embodiment as shown in FIG. 9, elements in common with the previous embodiments are identified with similar reference numberals, but raised by 100, and a detailed description thereof will be omitted. In the sixth embodiment, the input signal source 111 is connected to an input point 110 which is connected through the first and second bias voltage sources 113 and 114 to the bases of the transistors 123 and 125 of the first and second differential amplifiers 121 and 122. Similar to the third embodiment (FIG. 6), the collectors of the transistors 123 and 125 of the differential amplifiers 121 and 122 are coupled jointly to the emitters of the transistors 133 and 134 of the first transistor pair 131 while the collector of the transistor 125 of the second differential amplifier 122 is jointly coupled to the emitters of the transistors 135 and 136 of the second pair 132. The collectors of the other transistors 124 and 126 of the first and second differential amplifiers 121 and 122 are both coupled to ground. The feedback conductor 137 couples the collectors of the feedback transistors 133 and 135 to the input point 110, while the load resistor 119 extends between the collectors of the output transistors 134 and 136 and ground.
The embodiment of FIG. 9, which omits the operational amplifier 12, is highly suited for applications in which the cost of the device is to be minimized.
A seventh embodiment of the invention is illustrated in FIG. 10. Elements in common with the previous embodiments are identified with the same reference characters, but raised by 100 and a detailed description thereof is omitted. The seventh embodiment is a practical version of the embodiment of FIG. 9, and incorporates multi-emitter bias elements and current sources as in the fifth embodiment (FIG. 8). The embodiment of FIG. 10 is well suited for integration as a semiconductor integrated circuit.
In this embodiment, the transistors 124 and 126 of the differential amplifiers 121 and 122 are constructed as two-emitter transistors, and the diode-connected bias transistors 157 and 158 are also constructed as two-emitter transistors.
The ratio K 1 of the current through the transistors 124 and 126 to the current to the transistors 123 and 125 is established by the use of the multi-emitter transistors 124 and 126, and by the use of the multi-emitter transistors 157 and 158 to provide bias voltage thereto. The constant K 0 of equation (32) can be readily determined by the construction of the various transistors hereof as multi-emitter transistors.
Thus, the output voltage at the terminal 171 will vary according to the input current from the source 111, and the gain of the circuit will vary exponentially with the control voltage V C applied between the bases of the transistors 133, 136 and the bases of the transistors 134, 135.
Having described specific preferred embodiments of this invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.
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A gain control circuit particularly suitable for compressing or expanding the dynamic range of an audio signal, and thereby reducing noise produced during recording and playback comprises an input circuit receiving an input signal, first and second differential amplifiers each supplied from the input circuit with a signal derived from the input signal, with the amplifying elements of each being complementary to the amplifying elements of the other, a first pair of transistors having their emitters coupled to the output of the first differential amplifier and a second pair of transistors having their emitters coupled to the output of the second differential amplifier. The transistors of each pair are of the same conductivity type as the amplifying elements of the associated differential amplifier. The collectors of the transistors of each pair are jointed respectively to the collectors of the corresponding transistors of the other pair. Control voltage input terminals are respectively connected to one transistor of each pair and an opposite transistor of the other pair. A feedback signal is applied from the joined collectors of the one transistors to the input circuit, and an output current is applied from the joined collectors of the other transistors to an output stage which can include a load resistor or a current-to-voltage converter circuit. This arrangement prevents variation in total static current when gain is varied, thereby achieving a superior signal-to-noise characteristic.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention pertains generally to solar panels and assemblies therefor, and more particularly to a solar heat collector panel and assembly coming under the general classification of solar heaters, and classified in a more particular sense as a solar heater especially adapted for heating water pumped through the collector panel.
2. Description of the Prior Art
Among the most important directions in which research is presently being conducted for the purpose of conserving energy, is in the development of solar heating systems. Many of these have been designed, for example, for use in residences, although obviously they are not restricted to this particular usage. In a solar heating system, it is well known to provide an assemblage of like, solar heat collector panels. These are joined to provide a bank of said panels, and this grouping of the collector panels is often so arranged as to be especially adapted to be exposed to the rays of the sun. Typically, water is pumped through the panels, and is heated by the solar energy to which the panels are exposed. The water may thereafter be utilized for any suitable purpose, as for example, the heating of the residence in which the collector panels are mounted, the heating of water in a domestic hot water heating system, or perhaps for both of these highly desirable purposes.
One of the problems that has been encountered in the prior art resides in the excessive cost of manufacture of solar heat collection panels of the type described. In many instances, these require, by reason of their inherent design, the use of highly expensive metals or other materials of which the panel is to be constructed.
Or, it is often true that high costs result from the relatively complex design of the components of the collector panel. Again, this is a factor that contributes to an undesirably great expense in the initial manufacture of the panels, and as a result this has militated against the commercial development of the collector panels.
In still other instances, it has been found that the cost of assembling the components of the panels has been too great. Once again, the high cost of manufacture of the collector panel has prevented its widespread commercial development, even though the panel itself may operate with a high degree of efficiency.
All of these factors have contributed toward slowing the development of solar heating systems, and in particular the development of solar heat collector panels designed specifically for employment in such systems.
SUMMARY OF THE INVENTION
The present invention aims to overcome many of the difficulties that have heretofore been encountered in the development and manufacture of solar heat collector panels. It is proposed to accomplish this by providing a collector panel, and a panel assembly that utilizes the panel as its main component, such as to first of all permit the use of very inexpensive materials, specifically a low cost sheet metal such as is commercially known as roofing tin.
Secondly, the invention comprises a solar heat collector panel wherein the number of components required for manufacture of the complete panel is kept to a complete minimum. In particular, the panel comprising the present invention makes use of two rectangular, superposed sheets of inexpensive roofing tin, the lower sheet being folded over the periphery of the upper sheet and being secured along said periphery, by inexpensive mechanical expedients well known in the roofing trade.
The invention further comprises the stamping of the superposed sheets with integral corrugations, the several corrugations of the upper sheet extending in one direction, in parallel relation, normally longitudinally of the upper sheet. The corrugations of the lower sheet extend transversely of the lower sheet, at its ends, in perpendicular relation to the corrugations of the upper sheet. Upon connection of the sheets, the corrugations of the lower sheet are automatically brought into communication with the ends of the corrugations or channels of the upper sheet, so as to define inlet and outlet manifolds, through which water is supplied to and discharged from the channels of the upper sheet. In this way, the invention provides a basic solar heat collector panel of exceedingly inexpensive design and construction, both as to the materials used therein and as to the labor required for construction of the completed panel.
Summarized further, the invention also includes a solar heat collector panel assembly, that comprises a frame that can be readily formed from extruded materials such as aluminum or the like, and which is so designed as to define a plurality of superposed slideways or retention slots. The panel assembly includes, as its outermost component, a pair of spaced glass panel members, which when mounted define between them a dead air space, so as to provide a desirable outer insulative effect while still permitting free and full passage of the rays of the sun to the above described collector panel, which is mounted in the frame immediately below the dual glass pane structure.
Also mounted in the frame, below the collector panel, is a thickness of thermal insulation, which could, for example, comprise the insulation sold under the name "Fiberglass" manufactured and sold by Dow-Corning Corp. of Midland, Michigan. The insulation is sandwiched between the solar heat collector panel and a base of plywood or the like.
The panel assembly described can be joined with other similar assemblies, in a roof of a dwelling or commercial establishment, in a position such as to utilize to the maximum the solar radiation energy directed against the roof. Water pumped through the several collector panels of the panel assemblies that are so arranged is thus heated and directed elsewhere for the purpose of heating the interior of the building, heating water in a domestic hot water system, or for any other purposes found desirable or necessary.
BRIEF DESCRIPTION OF THE DRAWINGS
While the invention is particularly pointed out and distinctly claimed in the concluding portions herein, a preferred embodiment is set forth in the following detailed description which may be best understood when read in connection with the accompanying drawings, in which:
FIG. 1 is a top plan view of one of the solar heat collector panels, per se, constructed according to the present invention, a portion being broken away;
FIG. 2 is a bottom plan view thereof, portions being broken away;
FIG. 3 is a longitudinal sectional view of the collector panel, portions being broken away, taken substantially on line 3--3 of FIG. 1;
FIG. 4 is an enlarged, detail sectional view taken transversely through the collector panel, substantially on line 4--4 of FIG. 1;
FIG. 5 is a partially exploded perspective view, illustrating one of the panel assemblies as it appears in a partially assembled state;
FIG. 6 is a greatly enlarged, fragmentary, detail transverse sectional view through one of the sides of the panel assembly, substantially on line 6--6 of FIG. 5;
FIG. 7 is a view similar to FIG. 6, showing a modified construction; and
FIG. 8 is an enlarged, perspective view of a hold-down clip used in the modified form illustrated in FIG. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The solar heat collector panel 10 illustrated in FIGS. 1-3 includes a flat, elongated, rectangular bottom sheet 12 formed in a preferred embodiment of an inexpensive yet durable and strong metal, as for example, common roofing tin suitably plated or coated to ward off corrosion. The bottom sheet 12, as seen from FIG. 2, includes, at one end, a transverse corrugation 14 terminating at its opposite extremities in closely spaced relation to the opposite longitudinal edges of the bottom sheet. At the opposite end of the bottom sheet 12 there is formed a similar corrugation 16, extending transversely of the bottom sheet. Corrugations 14, 16 respectively define inlet and outlet manifolds for the solar heat collector panel, and in a preferred embodiment, are integrally stamped or formed in the bottom sheet, as readily seen from FIG. 3. Thus, there is provided a simple and highly inexpensive way of defining the inlet and outlet manifolds, without necessity of attaching special channels formed separately from the bottom sheet itself.
As seen from FIG. 2, attached to the corrugation 14, at one end thereof, is an inlet pipe 18, which supplies water to the manifold 14 from a suitable source, as for example, the inlet pipe may extend from the outlet end of a domestic hot water system or domestic hot water heating system, so as to provide the panel with a continuous source of water for reheating by solar energy, after heat has been taken from the water during passage thereof through the domestic hot water heating system.
Preferably, the inlet pipe 18 opens into the inlet manifold 14 at a location adjacent an end of the inlet manifold, near one corner of the collector panel.
Outlet manifold 16 is similarly formed near the opposite end of the bottom sheet 12, and in similar fashion is connected to an outlet pipe 20, which returns to the domestic system the water that has been heated by solar energy after passing from the inlet manifold 14 over the full length of the panel 10, to the outlet manifold 16. In the preferred embodiment, the outlet pipe 20 is located adjacent a corner of the panel 10 diametrically opposite the corner near which the inlet pipe 18 is disposed.
No effort has been made herein to indicate the pump, or the components of the hot water heating system from which the water flows to the pipe 16 for reheating within the panel, and for recirculation back to the hot water heating system via the outlet pipe 20. The components of a complete hot water heating system are known in and of themselves, and as an example, the panel 10 comprising the present invention could be connected in a system such as has been disclosed in U.S. Pat. No. 4,029,080 issued to Warren on June 14, 1977.
The solar heat collection panel 10 includes as a second main component thereof, an upper sheet 22. This, like the lower sheet, is formed of an inexpensive sheet metal material such as roofing tin protectively coated to resist corrosion.
The upper sheet 22 is formed with a plurality of straight, elongated longitudinal corrugations 24, terminating in closely spaced relation to the opposite ends of the upper sheet, and disposed in closely spaced, parallel relation over substantially the entire area of said upper sheet. As seen from FIG. 3, the longitudinal corrugations are integrally stamped or otherwise preformed in the roofing tin material of which the upper sheet is constituted, and open at their opposite ends into communication with the inlet and outlet manifolds 14, 16 respectively. Thus, merely by stamping the corrugations into the material of the lower and upper sheets, a complete pattern of flow channels results, covering substantially the entire area of the panel 10, with said pattern of flow channels resulting merely in response to peripheral connection of the sheets to one another. At the same time, the formation of the transverse and longitudinal corrugations in the bottom and upper sheet respectively provides for a strengthening or rigidifying of the sheet material, so that each sheet has a built-in resistance to deformation from its generally planar form.
As seen from FIG. 4 and also from FIG. 1, the upper and lower sheets are spot welded together at locations 26 occurring at spaced intervals along the length of the panel, between adjacent longitudinal corrugations 24 of the upper sheet. The provision of the spot welds 26 at spaced locations, leaves water free to flow between adjacent longitudinal corrugations at all points where the spot welds have been omitted, as shown at 28 in FIG. 4. This cross-flow of water between adjacent longitudinally extending corrugations 24 assures that there will be a uniform dispersion of the water over the entire area of the solar heat collection panel, with the water thus being given maximum exposure to solar radiation so as to correspondingly assure the greatest amount of efficiency in respect to elevating the temperature of the water as it passes from the inlet to the outlet pipes 18, 20 respectively. Further, the passage of the water through the low, shallow cross-flow areas 28 occurring between adjacent longitudinal corrugations, in effect causes the water to be formed into a relatively thin sheet of water as it passes through the cross-flow areas, thus still further improving the exposure thereof to solar energy and increasing the heating effect achieved by the panel structure that comprises the present invention.
As previously noted herein, the use of superposed sheets of inexpensive metal material such as roofing tin permits the sheets to be connected at their peripheries by inexpensive means that lends itself to mass production methods. Thus, in the illustrated, preferred embodiment (see FIGS. 1 and 6), the material of the bottom sheet is folded along its several edges over the corresponding edges of the upper sheet, as shown at 30. Over the full length of the fold, any suitable means is employed to prevent leakage through the joint, as for example, the welding of the folded over edge 30 to the edge of the upper sheet can be used as shown at 31 in FIG. 6. Or, any suitable sealing material, not shown, can be employed between the folded over edges. Means for joining separate sheets of metal material in a manner to prevent leakage are of course well known in the sheet metal art, and hence need not be specially illustrated and described herein other than by showing one such means as at 31.
A solar heat collector panel 10 formed as illustrated and described herein can be employed advantageously in any of various environments, that is, it can be used in any of various supporting frames or mountings where it will receive full exposure to the rays of the sun and hence will discharge its intended function efficiently. In this connection, one such arrangement is illustrated in FIGS. 5-8 and is believed in itself to be a novel and efficient way of utilizing a solar panel such as has been illustrated in FIGS. 1-4. In FIGS. 5-8, and considering first the form shown in FIGS. 5 and 6, the solar panel 10 has been illustrated in a panel assembly generally designated 32 formed in the illustrated embodiment as an elongated, flat, rectangular unit capable of being assembled with other, similar units in a roof of a building, not shown, such as shown, for example, in the above mentioned Warren patent. It will be understood, in this regard, that when a plurality of the panel assemblies 32 are mounted in side and end abutting relation, the inlet pipes 18 can all extend from a common source of water that needs to be reheated after passage through the domestic hot water heating system. Similarly, the outlet pipes 20 of the several collector panels 10 of panel assemblies 32 can all extend into a common conduit, not shown, through which the heated water is returned to the domestic hot water heating system after being reheated within the solar panels 10.
In any event, the panel assembly 32 in a preferred embodiment includes a rectangular frame 33 which, in the illustrated embodiment includes a pair of longitudinal frame members 34, and end frame members 36, 38. The longitudinal frame members 34 can be formed of extruded aluminum or other material capable of being readily formed to the cross-sectional configuration shown in FIG. 6 or in FIG. 7. It may be possible, for example, to utilize a suitable extrudable plastic material, and it is mainly important that the material be capable of manufacture at relatively low cost, and have the requisite characteristics of durability, resistance to warpage, and strength in retaining in their proper relationship the housed components of the frame assembly.
In a preferred embodiment, the end frame member 36 would be first joined permanently to the respective longitudinal frame members 34, and could be of a cross-sectional configuration similar to that provided for the end frame members and shown in FIG. 6. The end frame member 38, however, is preferably a removable member, which initially is left off for the purpose of permitting the several components of the assembly to be slid into the initially three-sided frame comprised of the members 34 and the end frame member 36. For example, the end frame member 38 might be a simple, flat piece such as shown in FIG. 5, that is, it need not have inwardly facing slots such as are shown in the cross-sectional view of the longitudinal frame member 34 and that may be incorporated in the permanently attached frame member 36.
In this connection, and considering the particular cross-sectional configuration of the longitudinal frame members or sides 34 of the assembly, each of said frame members 34 includes, adjacent its top surface, inwardly facing guide or retention slots 40-42 into which may be slid glass panes 41-43 respectively. If desired, other transparent material can be utilized instead of glass, but in the illustrated example glass is employed and the panes are separated to define between them a dead air space 48. The panes 41, 43 cooperate to define a transparent, double-paned transparent cover panel unit generally designated 44, which provides protection against the rain and the elements in general, and provides against heat loss in a direction outwardly of the assembly 32, while still permitting the free passage of the rays of the sun for the purpose of providing efficient heating of water flowing through the channels of the collector panel 10.
If desired, the glass panes 41, 43 can be sealably engaged in their respective retention slots, through the provision of a suitable flowable sealant 46. In this way, the assembly 42 is provided with an insulated, transparent outer covering defined by the unit 44, and said covering is easily assembled merely by bedding of the glass panes in the respective slots 40, 42.
Inwardly spaced from the transparent unit 44 is an inwardly projecting ledge or rib 49, extending continuously along the full lengths of the longitudinal frame members 34. Rib 49 is formed with an inwardly facing retention slot 50, adapted to receive the sealed, folded edge 30 of the solar collector panel as shown to best advantage in FIG. 6. It will be understood that a suitable sealant or adhesive can be employed to maintain the solar panel in place after it is slid into the slots 50, this being considered sufficiently obvious as not to require special illustration herein.
In a preferred embodiment, a space 52 is left between the glass unit 44 and the collector panel 10, and this provides an additional insulative effect between the solar panel and the glass unit itself.
Referring to FIG. 6, integrally formed at the base or bottom of each of the frame members is an inwardly projecting, longitudinal base rib 53, having an inwardly facing retention slot 54 adapted to receive the opposite side edges of a plywood base panel 56, which can be sealably retained within the associated slots 54 by means of a suitable adhesive 58. A substantial space is left between the panel 10 and the plywood base member 56, and this space is preferably filled with a suitable heat insulation material 60, as for example "Fiberglas", a material made and sold under this mark by Dow-Corning of Midland, Michigan.
In a preferred embodiment, the total thickness of one of the assemblies 32 would be on the order of perhaps 3 and 1/2 inches, so that the space occupied by the insulation 60 might well be on the order of about 1 and 1/2 inches, although of course it will be understood that these dimensions are merely rough and approximate, and are not critical to successful operation of the invention.
It may further be noted that the assembly may proceed as follows: first, with the frame left open at one end, the panel 56 can be slid into the frame through the open end thereof to provide a base for the insulation 60. Then, the insulation can be applied in superposed relation to said base. Thereafter, the collector panel 10 is slid into place, through the open end, being captured within the retention slots 50. Glass panel element 43 is then inserted, and finally the glass panel element 41 is inserted as shown in FIG. 5. When the several components have been mounted in the frame in this way, the end frame member 38 is applied, and for example, can be secured in position closing the hitherto open end of the frame, through the provision of screws 61 (see FIG. 5).
In FIG. 7 there is illustrated a modified or alternative construction for the panel assembly. In this figure the panel assembly has been designated 32a, and includes side frame members 34a cooperating with end frame members to define a rectangular frame 33a. The end frame members can be as shown in FIG. 5, that is, one end frame member can be permanently secured to the respective longitudinal frame members to provide an initially three-sided frame, and the remaining frame member can be applied after the several panel elements 56, 10, 43, and 41 have been inserted.
In any event, the cross-sectional configuration of the sides 34a of the frame differs somewhat from that shown in FIG. 6, since in this case, the solar panel 10 is held in place not by engagement in opposed, facing retention slots 50, but rather, by means of hold down clips. In FIG. 7 there are provided inwardly facing support ledges 62 for the panel 10, with the edges of the panel resting upon said ledges. At suitable locations along the length of the panel 10, hold down clips 64 are utilized, said clips having off-set ends cooperating with the ledge 62 to clamp the solar panel in place between the clips and the ledge. The clips are forced down tightly against the edges of the solar panel through the provision of elongated bolts 66, which extend through registering openings 68, 70 formed in ledge 62 and base rib 71 respectively. Nuts 72 are applied to the several bolts, and when tightened, cause the clamps 64 to bear tightly against the opposite sides of the solar panel.
Either the FIG. 6 or the FIG. 7 arrangements can be employed advantageously, according to the desires of the particular manufacturer.
The plywood panel 56 can be mounted as shown in FIG. 6, or alternatively, in either form of the invention can be held in place through the provision of suitably spaced wood screws or the like threaded into the plywood panel from the bottom of the frame assembly.
The several assemblies 32 can be mounted and incorporated in a roof structure in any suitable fashion, or alternatively could be embodied in a wall structure or in fact in any arrangement designed to facilitate the application of solar radiation energy to the collector panel 10. The arrangement shown in the above mentioned Warren patent, for example, is typical, and can be employed advantageously, utilizing panels formed according to the present invention.
It will be noted that considering the construction of the solar panel 10 in and of itself, this panel can be manufactured at very low cost and yet provides an efficient panel adapted to produce maximum exposure of water passing therethrough, to the rays of the sun, and adapted to promote maximum heat transfer for the purpose of efficiently heating the water or other liquid pumped through or otherwise caused to pass through the panel from the inlet to the outlet thereof. Inexpensive materials can be employed, and the labor involved in assembling the top and bottom sheets need not be skilled labor, thus reducing the cost of manufacture considerably. Even so, the construction, though inexpensive, is designed to promote maximum efficiency as regards the heating of the water passing through the panel, by integral stamping of the communicating transverse and longitudinal corrugations in the bottom and top sheets respectively, accompanied by the promotion of cross-flow between adjacent longitudinal channels with a view to assuring uniform dispersion of the water over the entire area of the solar panel, by forming of the water into a thin sheet of material which flows through the cross-flow areas 28, to promote heat transfer and as a consequence maximize the efficiency of the collector panel during normal use thereof.
The provision of a solar panel as described further facilitates its utilization as a component of a panel unit such as shown at 32 or 32a. The panel unit itself can be assembled at relatively low cost, by reason of the provision of the several guide slots and simple mounting means shown in FIGS. 6 and 7. Yet, a highly efficient frame assembly is provided, having an insulative outer cover means 44 that is yet adapted to freely pass the rays of the sun, an inner insulative means 60, a suitable base 56 which itself can have insulative value, and an open space such as shown at 52 between the collector panel and the protective outer cover means 44.
While particular embodiments of this invention have been shown in the drawings and described above, it will be apparent that many changes may be made in the form, arrangement and positioning of the various elements of the combination. In consideration thereof it should be understood that preferred embodiments of this invention disclosed herein are intended to be illustrative only and not intended to limit the scope of the invention.
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A solar panel has a series of channels through which water or other fluids may flow for exposure to and heating by solar radiation. Common to all the channels are inlet and outlet manifolds through which, respectively, the water is directed into and discharged from the channels. Construction of the panel is simplified and is rendered economical by fashioning of the same from a pair of superposed, inexpensive metal sheets, as for example roofing tin. The sheets are readily preformed with the manifolds and channels, in such fashion that when the sheets are connected along their peripheries by means of mechanical expedients well known in the sheet metal art, the several channels are automatically defined between the sheets, and are further automatically brought into communication with the inlet and outlet manifolds. By means of spot welding or the like, the sheets are firmly, permanently connected together, and the spot welding arrangement permits a cross flow between channels, to assure maximum exposure of the liquid to the effects of solar radiation.
A panel assembly is also disclosed, making use of the solar panel described above. The panel assembly is similarly inexpensively formed, through the provision of a supporting frame readily fashioned from an extrusion of aluminum or the like, said frame being designed with inwardly facing slots, adapted respectively to receive an outer glass panel, an inner glass panel, the solar panel disclosed above, a plywood base, and insulation interposed between the panel and base.
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The invention herein described may be manufactured and used by or for the Government for governmental purposes without payment to me of any royalty therefor.
This application is a continuation-in-part of application Ser. No. 158,977, filed Feb. 22, 1988, now abandoned, for HIGH-STRENGTH GRANULAR PARTICULATES FROM LOW-STRENGTH PRILLS.
INTRODUCTION
The importance of fertilizer products containing relatively high levels of nitrogen in closely sized granular form that exhibit properties of hardness (crushing strength) and low friability (wear resistance) sufficient to prevent fracturing and dust formation thereof during bulk blending, storage, handling, and/or subsequent application in the field has long been recognized as highly desirable and appreciated by both agronomists and process engineers practicing in the chemical fertilizer industry. Closed sized granular-form fertilizers are desirable and necessary to prevent segregation of granules by size when such fertilizers are subsequently incorporated with other materials in the production of custom bulk blends. The importance of size matching and uniformity of particles in bulk blends is discussed more thoroughly in TVA publication Z-49 reprinted from the proceedings of TVA Bulk-Blending Conference, Aug. 1-2, 1973, "Quality Control in a Bulk-Blending Plant."
Presently, urea is the leading solid-form nitrogen source for agricultural uses in the United States as reported by the USDA for 1980 (Consumption of Commercial Fertilizers, 1955-1980 fiscal years: Annual Reports: Economics, Statistics, and Cooperative Service: Crop Reporting Board, U.S. Department of Agriculture, Washington, D.C.). There are several characteristics of urea that are considered favorable and that have caused the chemical industry to increase production of urea and decrease output of ammonium nitrate, which ammonium nitrate is the second leading source of solid-form agricultural nitrogen. For instance, urea has a higher plant nutrient analysis than does ammonium nitrate (46 percent versus 33.5 percent nitrogen, respectively). Further, urea is classified as a nonhazardous material, whereas ammonium nitrate in combination with carbonaceous materials in certain proportions may be rendered an explosive compound and thereby suffers severe restrictions governing the storage, shipping, and handling thereof. In addition, there are many end product uses of urea other than for fertilizer use, such as for example, in the production of certain plastics, glues/cements for production of plywood and other building materials, and as a livestock feed supplement, which end products allow the chemical industry additional markets and year-round production scheduling instead of limiting the industry to seasonal production of nitrogen for the commercial fertilizer market as is the case in the production of ammonium nitrate. A further point in favor of the production of urea is that urea may be produced by any number of several known commercial processes, some of which processes are described in Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd Edition, Volume 23 (1983) pages 551-562. As may be seen, in several such applications, natural gas is the principal raw material in the production of ammonia whereby carbon dioxide is produced from the ammonia production process as a by-product. Urea is produced in such applications by the basic reaction of ammonia and carbon dioxide at elevated temperatures and pressures in the form of aqueous solutions of urea normally in the concentration range of 70 to 80 weight percent. The urea solutions are subsequently concentrated and further processed in ways to produce solid-form particulates such as prills and/or granules by several known commercial finishing applications. Also see Kirk-Othmer, 3rd Edition, Volume 23 (1983) pages 562 and 564-572. Even with all of the advantages enumerated supra as they relate to the production and/or use of urea, it must be noted that the resulting produced urea particulates exhibit certain undesirable characteristics that restrict their usefulness from the engineering and marketing point of view. For instance, the tendency of solid urea particles to cake in storage is a disadvantage that varies in degree of severity depending on the treatment and finishing process used to produce the solid particulates. Such caking tendencies oftentimes make it necessary to employ additional processing to maintain the urea particles in their initial free-flowing condition. Another disadvantageous characteristic of urea is the exhibited tendency of the particles to fracture easily into smaller particles and form substantial quantities of dust while the product is being handled, transported, and applied to the fields. Aside from the health and safety concern for the dust in the workplace, there is also the economical consideration of recovering and reprocessing the dust generated in the urea handling operations. The lack of particulate strength (hardness) and low friability (wear resistance) again varies in degree of severity and is dependent on the finishing process used in producing the urea particulates.
The two general methods of producing solid urea particulates are known as air prilling and granulation or accretion. Air prilling was the initial finishing process and the process used most by national and international urea producers. Prilling is favored for its simplicity, relatively low capital investment requirements and economically attractive operating and maintenance costs. The practice of the art of urea prilling utilizes a tall enclosed tower. Urea in the form of a highly concentrated solution or melt is pumped to or otherwise introduce atop the tower wherein the urea solution or melt is formed into droplets and allowed to free fall to the bottom of the tower through an upward-directed cooling airflow which action solidifies the solution or melt into solid particles or prills. Urea prills from commercial prilling processes are usually relatively small in size, less dense, and suffer from low hardness and high friability when compared to particulates produced from granulation processes. Urea prills are preferred for use as a livestock feed supplement and as raw material in several industrial processes; prills are least preferred for agronomic applications aforementioned. The second method of producing solid urea particulates is described in general terms as the art of granulation or accretion. This art provides for the initial generation of small seed particles and increases of such particles to the predetermined product size by gradual external addition; fusion and/or inclusion of thin layers (coating) of like material in the form of concentrated solutions and/or melts. The granulation processes normally utilize a rotating drum or pan which is designed to form a cascading bed or curtain of recycled undersize and seed particles onto which the urea solution or molten urea is sprayed wherein accretion takes place. Urea particulates as granules produced by any of several commercial granulation processes usually have favorable characteristics for storing, handling, incorporating into bulk blends, and direct application to the field.
Presently, oil-producing nations worldwide have begun producing prilled urea as a means of utilizing and marketing surpluses of natural gas from their oil field activities, whereas previously, the natural gas was either pumped back into the ground or burned off onsite. The added production has served to create vast surpluses of economically priced prilled urea for which the chemical industry is seeking profitable means of utilization.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a granulation process and provides for new and improved apparatus eminently useful for production of high-strength urea granules from low-strength urea prills. It will be appreciated by the chemical fertilizer industry and especially those skilled in the art of urea granulation that the practice of the present invention will result in the production of a predetermined and closely sized, urea-granular product of superior strength that is highly desirable and necessary for the production of nonsegregating bulk blends, sulfur-coated urea, and for direct application to the field. It will also become readily apparent to those skilled in this art that the practice of the present invention results in significant cost benefits in the commercial production of granular urea while utilizing low-cost, surplus urea prills to produce a highly marketable product. Still another benefit derived from the practice of the present invention allows the chemical fertilizer industry to increase the rate of production of granular urea to accommodate the seasonal demand for agricultural nitrogen inherent to the commercial fertilizer market.
A principal consideration relating to the practice of the present invention is the selection and use of methods and/or means wherein the modus operandi comprises the use of low-strength urea prills as substrate to produce high-strength granular urea.
2. Description of the Prior Art
There is a special need within the chemical fertilizer industry for efficient/economical, continuous processes and apparatuses capable of high-capacity production of high-quality urea fertilizer in predetermined, closely sized granular form. It will become apparent and appreciated by those versed in this art that the present invention is particularly well suited for meeting that special need and furthermore that the present invention is also readily adaptable on small scale to the requirements of specific industries such as, for example, the production of coated pharmaceuticals, candies and/or other similar applications. Therefore, the discussions and disclosures in the following sections describe the prior art and the application of the present invention to the production of fertilizer, both for the standpoint of granulation, i.e., gradual increase of the undersize nuclei to the desired product size by successive layering (accretion) and coating or incorporation of dissimilar fertilizer compounds such as, for example, incorporating primary and secondary plant nutrients within the granules or otherwise applying to the surface of substrate particulates permeable or semipermeable coatings of natural or synthetic polymeric compounds, oils, waxes, asphaltic and/or paraffin mixtures, and combination of such material for the purpose of the production of controlled release and other fertilizer products of proven desirable characteristics which can be produced, by my noncomplicated methods and equipment, at reasonable costs.
U.S. Pat. Nos. 3,117,020, Fabris et al. Jan. 7, 1964; 3,165,395, McCamy et al. Jan. 12, 1965; and 3,211,522, Shurter et al, Oct. 12, 1965, disclose various methods and means for the granulation of undersized fertilizer compound nuclei (recycled fines from screened product) by spraying a hot, concentrated aqueous solution or a nearly anhydrous melt of the compound into a rolling bed of the nuceli in an inclined, rotating pan. Although there is some coating action, most of the granulation, or increase to product size, is accomplished by agglomeration, or sticking together, of a number of the nuclei by the solidifying melt or solution. The granules are relatively rough and irregular, compared with layer granulation (see later section), and coating per se is minimal. The unit has little application as a true coating unit because of its natural classification action.
In U.S. Pat. No. 2,815,376, Knowlton et al. Dec. 3, 1957, there is disclosed a process for the granulation of fertilizer compounds by the spraying, or simple mixing, of the undersized fertilizer compound nuclei with a hot solution or melt of the compound in a paddle mixer, i.e., a blunger or pug mill. Again, particulates are formed by agglomeration of several nuclei into a single, larger particle bound together by the solidifying melt. Little coating action is achieved and the particles are rough and irregular.
It has also been shown that granulation, predominantly by a true coating or layering action, can be accomplished by spraying the hot solution or melt of a fertilizer compound into a fluidized bed comprised of undersized compound nuclei. For instance, as disclosed in U.S. Pat. No. 2,600,253, Lutz, June 10, 1952, ammonium nitrate or ammonium sulfate fertilizers are produced by reacting ammonia and nitric acid or sulfuric acid in a fluidized bed of undersized ammonium nitrate or ammonium sulfate particles. In other applications, principally in Europe, a hot melt or concentrated solution in the compound is sprayed into the fluidizing gas (hot air) at the bottom of the fluidized bed. The fluidized bed does achieve truly random motion of the substrate particles, and therefore results in a homogeneous mass with respect to particle size which is a consideration so necessary in uniformly coating particles of varying sizes. However, the fluidization process is inherently costly, it requires close control, and it does not permit visual examination of the sprays or product in the coating section.
In the fertilizer industry, granulation, i.e., increase in particle size from undersize (recycled fines) to product size by coating, and coating for the purpose of imparting special characteristics to the fertilizer substrate, such as controlled release or anticaking properties, is most widely practiced in essentially horizontally disposed rotary drums either with or without internal lifting vanes or flights. In U.S. Pat. No. 3,398,191, Thompson, et al, Aug. 20, 1968, disclose the granulation of urea or ammonium nitrate by spraying an essentially anhydrous melt (98-99.5 percent) of the coating compound from multiple spray heads spaced at intervals along the entire length of the coating section onto a rolling bed and into a showering curtain of undersized nuclei (recycled fines) maintained in motion by the rotation of a slightly inclined (from horizontal) rotating drum equipped with longitudinal lifting vanes or flights specially designed to form continuous longitudinal curtains of falling particles that move in succession across the entire cross-sectional area of the contact or coating zone of the drum in a manner familiar to those versed in the art of horizontal rotary drum coolers and dryers. Transverse retaining rings or dams at the feed end and discharge end of the coating section maintain an adequate depth of bed. Cooling air (ambient temperature) is drawn countercurrently through the showering curtains of falling particles to cool and solidify the layers of melt on the nuclei. The drum is extended beyond the contact zone to a cooling zone equipped with the lifting flights but without spray heads with which to further cool the product with such countercurrent flow of air.
Other essentially identical examples of this form of prior art featuring the falling curtain across the full cross-sectional area of the rotary drum are disclosed in U.S. Pat. Nos. 3,092,489, Smith, June 4, 1963; 3,277,789, Tytus et al, Jan. 4, 1966; and 3,232,703, Thompson et al, Feb. 1, 1966.
The falling curtains of particles across the full cross-sectional area of the drum, as described in the above prior art, approaches the degree of random motion of substrate, and therefore of homogeneity with respect to particle size, that is so important to the uniform coating of a mass of particles of different sizes, but it is now believed that the arrangement of spray heads within the shower of falling particles, and therefore in actual contact with many of the falling particles as a result of the falling curtains across the entire cross-sectional area of the drum, has certain serious disadvantages. Among the most serious of these disadvantages are (1) the lack of control of the spray distance, i.e., the distance that the individual droples of atomized liquid spray travels before impinging upon the moving substrate particles; some of the particles fall on each spray head, some immediately in front of it, some fall at the optimum distance, and some fall well beyond the optimum distance but are still contacted by the spray. This leads to agglomeration of the substrate particles when too short, or too rough--ineffective coatings, when too far; (2) the actual contact of many of the falling particles with the hot spray heads leads to melted substrate, which drips onto the substrate bed, causing serious agglomeration of some of the substrate; (3) visual monitoring of the invidual spray operation of impossible and (4) dusting is serious when the entire section of the rotating drum is filled with falling particles, dust formed by attrition, and solidified spray mist, all of which can be carried from the system by the cooling or heating air flowing through the coating unit. This dust problem substantially increases antipollution equipment requirements.
The coating procedure, as taught in U.S. Pat. No. 3,295,950 Blouin et al. Jan. 3, 1967; U.S. Pat. No. 3,342,577, Blouin et al, Sept. 19, 1967; and U.S. Pat. No. 3,903,333, Shirley et al, Sept. 2, 1975, are almost identical in nature, i.e., the directing of the atomized coating material only onto the rolling bed of substrate in a horizontal rotary drum having a relatively smooth interior with no lifting vanes or flights as is shown and provided for in U.S. Pat. No. 2,741,545, Nielsson, Apr. 10, 1956. The latter art, i.e., Shirley U.S. Pat. No. 3,903,333, discloses certain improvements in the former which, according to the example data disclosed, does result in somewhat more uniform coatings than those of the former art, i.e., Blouin U.S. Pat. No. 3,295,950.
However, both practice essentially the same approach as described above and, therefore, both suffer from the same serious disadvantage that precludes a truly homogeneous moving bed of particles of different sizes and therefrom true uniformity of the coating, namely, the segregation by particle size of particles of varying sizes that occurs in a smooth, horizontal rotary drum. This segregation or demixing is well documented in the extensive work of Campbell et al [Chemical Engineering 73(19), 179-185 (Sept. 12, 1966)]and McDonald et al [British Chemical Engineering 7(10), 749-753 (October 1962--Part I, ibid 7(11), 823-27 (November 1962)--(Part II; and ibid 7(12), 922-23 (December 1962)--Part III]. Although the degree of demixing or segregation that occurs in a smooth drum may be reduced by proper choice of operating and equipment variables such as bed depth or degree of drum loading, drum speed (expressed as percent of critical speed, the critical speed, i.e., revolutions/minute, of a smooth drum being defined as 76.5 /√D, where D=drum diameter in feet), and ratio of drum diameter to drum length, it cannot be eliminated. As a result, smaller particles tend to segregrate from the larger particles by going to the point of lowest particle velocity, namely, the center of the cross-sectional area of the bed and pass on through the drum without coming to the surface of the bed. This, of course, prevents these particles from being coated by the liquid spray.
The problems associated with segregation of particles by size within a horizontal rotating drum during application of coatings and/or granulation have been significantly reduced in the art disclosed in U.S. Pat. No. 3,877,415, Blouin, Apr. 15, 1975. The apparatus in this disclosure provides for a near homogeneous (with respect to particle size) dense mass of sized particles in random motion so that highly uniform coatings of the same or of different solids can be applied to each particle by conventional spray-coating with the liquefied coating material(s). The apparatus is a horizontal rotary drum containing lifting flights. A novel deflector pan is fixed in space inside the upper section of the drum which deflects particles falling from the lifting flights to the side of the drum where they form a narrow, dense falling cascade. The coating material is sprayed onto the cascading particles, preferably as they free-fall after leaving the lower edge of the pan. However, if desired, some or most of the coating material may be directed onto the top edge of the moving bed including the juncture of the cascade therewith. Also see U.S. Pat. No. 3,991,225, Blouin, Nov. 9, 1976.
Further improvements in the prior art of Blouin's disclosure supra were revealed in the procedures taught in U.S. Pat. No. 4,213,924, Shirley et al, July 22, 1980; U.S. Pat. No. 4,424,176, Shirley et al. Jan. 3, 1984; and U.S. Pat. No. 4,506,453, Shirely et al, Mar. 26, 1985. In these further improvements of Shirley et al, there is disclosed an improved process for the granulation or coating of hygroscopic or nonhygroscopic materials where melt is sprayed onto cascading granules of common or uncommon substrate in an enclosed vessel and where the heat given off by solidification of the melt is absorbed by evaporation of water. The water is atomized into the granulator as an extremely fine mist and evaporation is effected without impingement of such mist on either the granules or granulator internals. It was further disclosed by Shirley et al supra that the installation of two or more inclined deflector pans in step fashion in the rotary granulation drum allows the substrate elevated by lifting flights from the cascading bed in the drum to fall onto the pans. Material cascading from the pans form the upper and lower falling curtains of substate. Molten or highly concentrated urea solution is sprayed with a high degree of precision horizontally onto the lower falling curtain of substrate usually throughout the entire length of the lower falling curtain. Air cooled by the evaporation of water, which now and later will be referred to as evaporative cooling, is forced upon and through the uppermost falling curtain of substrate (recycle and nuclei) by several internally-mounted propeller fans to effect the high degree of cooling and removal of heat released in the rotary granulation drum by the solidification of molten or highly concentrated urea solution. For purposes of teaching, disclosing, and claiming the instant invention the full teachings and disclosures of Blouin U.S. Pat. No. 3,991,225 and 3,877,415 as well as Shirley U.S. Pat. Nos. 4,506,453 and 4,424,176 supra are herewith and hereby incorporated herein by reference thereto.
Those skilled in the art are well aware of heat transfer technology as it applies to fluid beds and spouted fluid beds such as have been disclosed in U.S. Pat. No. 4,219,589, Niks et al, Aug. 26, 1980, and in U.S. Pat. No. 4,217,127, Kono et al, Aug. 12, 1980, respectively. Fluid-bed technology is recognized to be one of the best heat transfer means between a gas and solid particles. The heat transfer rates within the bed are exceptionally high.
As disclosed in the teaching of Shirley et al supra, many of the principles of fluid bed were emulated herein in part to achieve extremely effective means of heat transfer. It is also an objective of the present invention to make use of fluid-bed principles to achieve efficient heat transfer and at the same time to eliminate the less desirable features in the art as practiced by Shirley et al. In this respect, the present invention borrows from the fluid bed the principle that gas blowing through suspended solid particles in a more or less dense phase, as in a fluid bed, is the best means of contact for heat transfer purposes and not as gas contact occurs in long rotary drums where gas flow is axial sometimes passing through, but mostly flowing parallel, to the showers of falling solid particles. More specifically, the present invention approaches the principles of fluid bed in the rotary granulation drum by design and action of the lifting vanes or flights and by means of a specially designed multipurpose assembly which comprises upper and lower deflector pans and a cooling-air distribution manifold to form the cascading recycle and nuclei into an upper and lower fixed falling curtain wherein essentially anhydrous urea solution or melt is sprayed hydraulically with great precision at low to moderate pressure at right angles to and along the full length of the lower curtain. Cooling air drawn from outside the facility by a single blower is forced upon and through the upper falling curtain through use of an air-distributing manifold located between and attached to the upper and lower inclined deflector pans and extends the full length of the falling curtain of substrate.
The embodiment of evaporative cooling in the procedures disclosed by Shirley et al supra is incorporated in 14-ton-per-hour falling-curtain urea-granulation plant located at the Tennessee Valley Authority's National Fertilizer Development Center, Muscle Shoals, Ala. Although the plant has been in operation since July 1983, the technology has not been well received by those versed in the art for, among other reasons, the equipment requires unusually high maintenance, the process is complicated and difficult to operate, and when it is operated improperly it causes caking and buildup on the shell and other internal parts of the rotary granulation drum.
Since of the objectives of the present invention is to develop a both a process and granulation apparatus which demonstrates reliability and simplicity in operation, the above-mentioned principle of evaporative cooling is not utilized therein because of its inherent disadvantages. Additionally, the degree of heat transfer and removal cited by Shirley et al for evaporative cooling is not needed in the practice of the present invention which now provides for heat transfer and removal from the rotary granulation drum by a much simpler and much more reliable method and/or means.
SUMMARY OF THE INVENTION
Prior art investigators have developed, taught, and disclosed methods and/or means which utilize in one way or another a number of approaches for producing fertilizers in granular form by the process of accretion, i.e., gradual increase of undersize and nuclei to the desired product size. More specifically, Blouin in U.S. Pat. No. 3,991,225 supra, Shirley and Shirley et al in U.S. Pat. Nos. 4,213,924, 4,424,176, and 4,506,453 supra have found that and taught the utilization and application of lifting flights and single and multiple deflector pans to the principles associated with fluid beds in the rotary granulation drum by causing the formation of falling curtains of homogeneous substrate of recycled undersize and nuclei which provide for the application of successive coatings of essentially anhydrous solution, thus accretion, coupled with the efficient cooling and heat removal from the rotary granulation drum by employing therein the technique of evaporative cooling.
Those skilled in the art will quickly realize and appreciate that the present invention combines certain favorable features of the prior art with new, novel, efficient, and simple techniques to provide a superior means of precision granulation to produce an economically attractive, high-quality, marketable granular urea. The process of the instant invention utilizes relatively low cost and loosely sized urea prills that are increased to predetermined and closely controlled product size. The poor-quality urea prills, utilized herein as feed, normally enter the process from storage, a portion of which is sized appropriately by screening to provide nuclei for granulation. Another portion of these same low-quality prills is routed to a urea melter, along with oversize and fines from the prilled urea screening system and oversize from the product screening system, to provide the essentially anhydrous urea melt or solution for the liquid phase of the instant granulation process. By improved process is equally applicable when the liquid phase is supplied from a urea-synthesis plant. Undersize recycle from the product screening system is returned to enter the rotary granulation drum along with urea-prill nuclei fed at a predetermined rate. The rotary granulation drum, with specially designed internals, causes the recycled undersize and urea-prill nuclei to form into fixed falling curtains. Essentially, anhydrous molten urea or solution is sprayed, with great precision, onto the bottom fixed falling curtain while cooling air at ambient conditions is blown onto and into the upper fixed falling curtain to provide the required cooling in the rotary granulation drum.
Granular urea containing oversize, product size, and undersize which is discharged from the rotary granulation drum is further cooled in a fluid-bed cooler to harden the granules to prevent breakage and thus, formation of unwanted dust. The cooled granules are then elevated and screened, oversize is returned to the urea melter, undersize recycled to the rotary granulation drum, and product size to storage. If necessary, the process provides for additional fluid-bed cooling of the product granules prior to their entering storage.
The gist underlying the concept comprising the principal embodiment of the present invention is that the process and apparatus utilizes low-strength, poor-quality, economically priced surplus urea prills that suffer from limited market acceptance to produce high-strength, high-quality, closely sized urea granules that enjoy greatly enhanced market acceptance. An added benefit to those that practice the art of the present invention is the realization of an energy saving ranging from about 17 to as much as about 25 percent by the fact that urea prills as nuclei, at ambient temperature rather than as a hot melt, are fed into the process and account for or make up from about 25 to about 33 percent of the resulting granular urea product thereby effecting significant cooling and heat removal from the rotary granulation drum.
OBJECTS OF THE INVENTION
In view of the above discussions of the problems besetting the state of the art relating to the production of high-strength granular particulates, it is therefore the principal object of the present invention to utilize the presently available, large surplus of poor-quality, low-strength urea prills to produce high-strength, closely sized urea granules of high quality.
Another object of the present invention was to utilize the presently available, large surplus of poor-quality, low-strength urea prills to produce high-strength, closely sized urea granules of high quality and to provide for the design of the process and apparatus used therefor and obtain in respect thereto for the uncomplicated, easily controlled, energy-efficient, high-capacity production of granular urea product.
Still another object of the present invention was to utilize the presently available, large surplus of poor-quality, low-strength urea prills to produce high-strength, closely sized urea granules of high quality and to provide for the design of the process and apparatus used therefor and obtain in respect thereto for the uncomplicated, easily controlled, energy-efficient, high-capacity production of granular urea product and to further provide that the resulting manufacturing process be flexible and capable of producing several distinct size ranges of granular urea product to accommodate the principal agriculture market, the special-purpose markets, such as for example, the lawn and garden fertilizer market and the forestry fertilizer market.
Still further and more general objects and advantages of the present invention will appear from the more detailed description set forth below, it being understood, however, that this more detailed description is given by way of illustration and explanation only and not necessarily by way of limitation since various changes therein may be made by those skilled in the art without departing from the true spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
My invention, together with further objectives and advantages thereof, will be better understood from a consideration of the following description taken in connection with the accompanying drawings and examples in which:
FIG. 1 represents a process flow diagram for producing granular urea from urea prills by a principal embodiment of the present invention utilizing a urea melter and a dry collector for process dust recovery.
FIG. 2 illustrates a process flow diagram for producing granular urea from urea prills by an alternate embodiment of the present invention in which the liquid phase or urea used for granulation is supplied by the output of a urea synthesis plant and the dust recovery by wet scrubbers.
FIG. 3 is a pictorial isometric view of the rotary granulation drum utilized in the practice of the present invention and which shows the relative positios of the deflector pans, cooling-air distribution manifold, and urea melt or concentrated urea-solution spray header.
FIG. 4 is a cross-section view of the granulation drum utilized in the practice of the present invention which illustrates the action of the specially designed internal equipment components and their relative locations therein.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now more specifically to FIG. 1, in the practice of the process of the present invention, poor-quality, low-strength urea prills from a source not shown enter the process via line 101 and means for control of flow 102 and proceed to splitter gate 103. Splitter gate 103 routes a portion of the urea-prill feed via line 104 to sizing screen 105 and the remaining portion of the urea-prill feed via line 106 to urea-melter feed surge bin 107. In addition to unscreened urea prills via line 106, dust via line 109 from the process recovered in dry collector 108, oversize via line 110 from product screen 111, oversize via line 112 and undersize via line 113 from urea-prill sizing screen 106 also is routed by conveyor means 114 to urea-melter feed surge bin 107 and collectively metered by weigh feeder 115 and line 116 to urea melter 117 at predetermined rates which provides the essentially anhydrous molten urea to provide the liquid phase of the instant granulation process. Urea melter 117 is provided with an internal heat source which may be in the form of steam introduced via line 118. Molten urea from urea melter 117 flows via line 119 into melt pump tank 120. As an optional feature of the instant invention, any of several conditioning-hardening agents can be added from a source not shown via line 121 into the melt pump tank 120 for incorporation into the anhydrous urea melt therein prior to introduction into a later mentioned granulation drum. The melt or resulting conditioned urea melt in tank 120 is introduced via pump 122 and line 123 to rotary granulation drum 124. Appropriately sized urea prills from screen 105 are routed via line 125 to surge bin 126. From surge bin 126, the appropriately sized prills are metered by weigh feeder 127 via line 128 in the amount approximately equal to 25 to 33 percent of the total melt feed rate and, along with undersize (recycle) from product screen 111 via line 129, is introduced into granulation drum 124. The action of the specially designed lifting flights and deflector pans in rotating granulation drum 124 act to form the substrate (sized urea prills and recycled undersize) into fixed falling curtains (not shown). Urea melt introduced via line 123 is sprayed onto and along the entire length of the lower fixed falling curtain (not shown) while an adjusted flow of ambient air from a source not shown is blown via line 130 into and through the entire length of the upper fixed falling curtain (not shown) and distributed thusly by a manifold (not shown) located between the upper and lower deflector pans (not shown) to furnish necessary cooling and temperature control in rotary granulation drum 124. Granular urea discharging from granulation drum 124 via line 131 and comprising oversize, onsize, and undersize is further cooled in fluid-bed cooler 132 to harden the granules thus reducing breakage and dust formation during screening and subsequent handling. Fluid-bed cooler 132 is operatively connected to blower 133 via line 134. The resulting cooled granules from fluid-bed cooler 132 are introduced via line 135 to elevator means 136 for transfer to product screen 111 for screening. Exhaust air from granulation drum 124 via line 137, process cooler 132 and line 138, and product cooler 139 and line 140 as well as from miscellaneous dust pickup points throughout the process, generally illustrated as line 141, is passed through dry collector 108 to recover the urea dust. Dust-free air is vented to the atmosphere by means of exhauster 142 and line 143. Cooled granules from elevator means 136 is appropriately screened at 111 with the oversize routed through feeder 115 to urea melter 117 via line 110 and conveyor means 114, undersize recycled via line 129 to granulation drum 124, and product-size granules routed via line 144 to diversion gate 145. If addition cooling is needed, the product granules are routed from diversion gate 145 via line 146 to product cooler 139. Product cooler 139 is operatively connected to blower 147 via line 148. Cooled product granules from product cooler 139 are moved, via line 149 to storage generally illustrated at 151. If such additional cooling is deemed unnecessary, product granules are routed from diversion gate 145 via line 150 to storage 151.
Referring now more specifically to FIG. 2 which illustrates an alternate embodiment of the process of the present invention, essentially anhydrous urea solution from a urea-synthesis plant (not shown) is utilized and process dust collected from the various pickup points is recovered by a later mentioned wet scrubber. Poor-quality, low-strength urea prills from a source generally illustrated at 201 enters this alterate process via line 202 and means of control of flow 203 and proceeds to sizing screen 204 where the urea feed prills are appropriately sized by properly selected screen cloths into factions of oversize, onsize, and undersize particles. Oversize prills via line 205, undersize via line 206 from sizing screen 204, in addition to oversize via line 207 from process screen 208 are transferred by conveyor means 209 and introduced via line 210 into dissolving tank 211. Dissolving tank 211 is provided with an internal heat source which may be in the form of steam introduced via line 212. Makeup solution for dissolving tank 211 is scrubber solution from web solution 213 and introduced therein via line 214. Urea solution from dissolving tank 211 via pump 215 and line 216 and urea solution via line 217 from a urea-synthesis plant (not shown) are fed to urea evaporator/concentrator means 218 at predetermined rates and at the usual concentration of 75 to 87 weight percent by appropriate metering devices (not shown). Essentially anhydrous molten urea from evaporator/concentrator means 218 and line 219 is routed into molten urea pump tank 220. As an optional feature of the instant invention, any of several conditioning-hardening agents can be added from a source not shown via line 221 into molten urea pump tank 220 for incorporation into the anhydrous molten urea prior to introduction into a later mentioned granulation drum. The molten urea or resulting conditioned molten urea in tank 220 is introduced via pump 222 and line 223 to rotary granulation drum 224. Appropriately sized urea prills from screen 204 are routed via line 225 to surge bin 226. Sized prills from bin 226 are metered by weigh feeder 227 and line 228 in the amount approximately equal to 25 to 33 percent of the total molten urea feed rate and, along with undersize (recycle) from product screen 208 via line 229, are introduced into granulation drum 224. The action of the specially designed lifting flights and deflector pans (not shown) in rotary granulation drum 224 act to form the substrate (sized urea prills and recycled undersize) into fixed falling curtains (not shown). Molten urea introduced via line 223 is sprayed onto and along the entire length of the lower falling curtain (not shown) while an adjusted flow of ambient air from a source not shown is blown via line 230 into and through the entire length of the upper fixed falling curtain (not shown) and distributed thusly by a manifold (not shown) located between the upper and lower deflector pans (not shown) to furnish necessary cooling and temperature control in rotary granulation drum 224. Granular urea discharging from granulation drum 224 via line 231 and comprising oversize, onsize, and undersize is further cooled in fluid-bed process cooler 232 to harden the granules thus reducing breakage and dust formation during screening and subsequent handling. Fluid-bed process cooler 232 is operatively connected to blower 233 via line 234. The resulting cooled granules from fluid-bed process cooler 232 are introduced via line 235 to elevator means 236 for transfer to product screen 208 for screening. Exhaust air from granulation drum 224 via line 237, process cooler 232 via line 238, product cooler 239 via line 240, as well as from miscellaneous dust pickup points throughout this alternate process, generally illustrated as line 241, is passed through wet scrubber 213 to recover urea dust. Essentially dust-free air is vented to the atmosphere by means of exhauster 242 and line 243. Steam condensate or water from a source not shown enters wet scrubber 213 via line 244 as needed. Resulting scrubber solution from wet scrubber 213 and line 245 consisting of dissolved urea dust in water is recirculated to wet scrubber 213 by pump 246 via line 247 and, as needed, scrubber solution is transferred from scrubber 213 via line 245; pump 246 and line 214 to dissolving tank 211 for makeup solution. Cooled granules from elevator means 236 is appropriately screened at 208 with oversize via line 207 routed to dissolving tank 211 via conveyor means 209 and line 210, undersize recycled via line 229 to granulation drum 224, and product-size granules routed via line 248 to diversion gate 249. If additional cooling is needed, product granules are routed from diversion gate 249 via line 250 to product cooler 239. Product cooler 239 is operatively connected to blower 251 via line 252. Adequately cooled granules from product cooler 239 are moved via line 253 to storage generally illustrated at 255. If additional cooling is deemed unnecessary, product granules are diverted from diversion gate 249 via line 254 to storage 255.
Referring now more specifically to FIG. 3 which is a pictorial isometric view of rotary granulation drum 301 utilized in the process of the present invention and which shows the relative positions of the lifting flights 302, a multipurpose assembly that includes the upper deflector pan 303, lower deflector pan 304, cooling-air distribution manifold 305, and urea-melt spray header 306 therein is illustrated and exemplary granulation drum of pilot-plant size that has a granulating capacity of 6,000 pounds per hour of product and is 7 feet in diameter and 10 feet long. Those skilled in the art of granulation will recognize and appreciate the simplicity of design and function of said vessel which provides for a granulation method, principally that of spraying essentially anhydrous molten urea via header 306 and line 307 with great precision onto the lower fixed falling curtain of undersize and urea-prill nuclei feed (not shown). It can be seen that rotary granulation drum 301 is a cylindrical vessel, the axis of which may be mounted horizontally or slightly below horizontal at the discharge end to facilitate solid particle movement through the drum. Granulation drum 301 is provided with feed-end retaining ring 308 and discharge-end retaining ring 309 or angular dams that form and retain the cascading bed of feed particles (not shown). Feed particles collectively made up from sized urea prills and undersize from sources not shown enter rotating vessel 301 via line 310 through fixed chute 311 which projects through the opening of feed-end dam 308. Granulation drum 301 is caused to rotate at the desired speed by a drive assembly (not shown) while mounted on rollers (not shown) in a manner familiar to those versed in the art of horizontal rotary kilns, dryers, and coolers.
The discharge end of rotary granulation drum 301 is equipped with closed and essentially gas-tight hood assembly 312, also familiar to those versed in the art of rotary drum coolers and dryer design. The lower section of hood 312 is provided with discharge port 313 for granular material exiting drum 301. Port 313 is funneled and/or otherwise shaped in such ways as to assist in the movement of granular material, which exits drum 301 via outlet chute 314. The top section of hood 312 is provided with gas port 315 and outlet duct 316 through which the cooling, heating, or ventilating gases are drawn from drum 301 by an exhauster or other means (not shown).
As shown in FIG. 3, multiple and evenly spaced lifting flights or vanes 302, which are longitudinal, are fixed to the internal wall of drum 301, are parallel to its axis, and extend approximately the entire length of drum 301. It can also be seen that upper deflector pan 303, lower deflector pan 304, and cooling-air distribution manifold 305 are constructed as a multipurpose assembly which is installed horizontally along the axis in the upper section of drum 301 and extends essentially throughout its length. Top
deflector pan 303 and lower deflector pan 304 are installed in step fashion such that the planes they form are approximately parallel to one another. Both pans are inclined counter to the drum rotation at angles so that feed particles elevated from the cascading bed (not shown) in drum 301 by lifting flights 302 discharge onto the pans and flow from said pans to form the particles into fixed free-falling curtains (not shown).
Cooling air, via line 317, introduced in drum 301 via duct 318 at velocities ranging from approximately 1,000 to 2,000 feet per minute, from a source not shown, is distributed at velocities usually ranging from about 80 to about 160 feet per minute across the length of the upper falling curtain of feed particles (not shown) by cooling-air manifold 305 located between the upper and lower pans. The side of manifold 305 adjacent to the upper falling curtain of feed particles (not shown) is provided with screen-covered opening 319 that is approximately equal to ten times the cross-sectional area of manifold 305. Depending upon anticipated operating conditions and other considerations, the ratio in commercial plants of opening 319 to the cross-sectional area of manifold 305 may range from about 8:1 to about 15:1. The pressure drop created by cooling airflow through screen-covered opening 319 serves to distribute the said airflow as desired along the length of cooling-air distribution manifold 305 which also serves to prevent feed particles and/or dust particles from entering therein. Cooling-air distribution manifold 305, which preferably is rectangular in cross-section, is provided with air-directional vanes (not shown) on its outside wall above and below the screen-covered opening 319 and extends the entire length of said opening. Cooling-air distribution manifold 305 which is fixed and sealed to upper deflector pan 303 and lower deflector pan 304, is also provided with baffles (not shown) at each end of screen-covered opening 319 to prevent bypassing; therefore, cooling air distributed by said manifold 305 is positively forced through and beyond the upper fixed falling curtain of feed particles to provide efficient and necessary cooling therein.
Referring now more specifically to FIG. 4 which is a cross-sectional view of rotary granulation drum 401 utilized in the process of the present invention and which illustrates its action therein and the relative position of specially designed internal equipment components, therein is illustrated an exemplary granulation drum for large pilot-plant application 7 feet in diameter and 10 feet in length. Granulation drum 401 is equipped with 40 evenly spaced lifting flights or vanes 402 installed at 9-degree intervals. Flights 402 are longitudinal and fixed to the internal wall of drum 401 parallel to its axis. They are flat, about 5 inches wide, 8 feet 10 inches in length, and canted about 15 degrees forward toward the rotation of drum 401 from a perpendicular with its shell.
A multipurpose assembly which includes top deflector pan 403, bottom deflector pan 404, and cooling-air distribution manifold 405 is installed in the upper section of drum 401. Said assembly is installed parallel to drum 401 axis and extends approximately the entire length of drum 401. Top deflector pan 403 is flat, 1 foot 11 inches side, 9 feet 2 inches long, and sloped at an angle of about 35 degrees from the horizontal and counter to the rotation of drum 401. Top pan 403 is attached to manifold 405 with hinges (not shown) and their connection sealed to prevent cooling air from bypassing and to allow the slope of deflector pan 403 to be adjusted without interrupting operation. Dust shield 406 is attached to the uppermost edge of deflector pan 403 and extends approximately vertically by downward and is of sufficient dimension to provide for overlapping the top of manifold 405 to prevent dust buildup in the generally triangular section shown atop manifold 405. Bottom deflector pan 404 is attached to lower edge of manifold 405 with hinges (not shown) and their connection sealed to prevent cooling air from bypassing and to allow its slope to be adjusted without interrupting operation. Bottom pan 404 which is sloped counter to the rotation of drum 401 at an angle of about 35 degrees, is flat, 1 foot 1 inch wide, and 9 feet 4 inches long. Top pan 403 and bottom pan 404 are installed in step fashion so that the planes they form are approximately parallel to one another. Cooling-air distribution manifold 405, which is located between and attached to top pan 403 and bottom pan 404, is rectangular in cross-section, 1 foot wide, 1 foot 4 inches high, and extends essentially the entire length of drum 401. The side of manifold 405 adjacent to upper fixed falling curtain of feed particles 407 is provided with screen-covered opening 408 which extends essentially the entire length of upper fixed curtain of feed particles 407. The area of said opening 408 is approximately equal to ten times the cross-sectional area of manifold 405. A pressure drop created by cooling airflow from a source not shown through screened opening 408 serves to distribute said airflow along the length of upper fixed curtain of feed particles 407 to provide necessary cooling and temperature control of the granulation process effected within drum 401. Cooling-air distribution manifold 405 is provided with air-directional vanes 409 located above and below screen-covered opening 408. Air-directional vanes 409 are flat, approximately 3 inches wide, extend the entire length of opening 408, and serve to direct cooling airflow from manifold 405 onto and through upper fixed falling curtain of feed particles 407.
Feed particles from a source not shown enter drum 401 to form cascading bed 410. As drum 401 rotates, feed particles from cascading bed 410 are elevated by lifting flights 402 which continually discharge said particles to form multiple moving falling curtains 411 which continually travel horizontally and in wave-like fashion toward the center of drum 401. Feed particles discharging from lifting flights 402 fall upon upper deflector pan 402 and flow from said pan to form upper fixed curtain 407. Feed particles flowing from upper fixed curtain 407 and moving curtains 411 fall on and flow from lower deflector pan 404 to form lower fixed falling curtain 412. Essentially anhydrous molten urea from a source not shown is sprayed with great precision onto and along the entire length of lower falling curtain of feed particles 412 by means of urea spray header 413 to produce closely sized granular urea of high strength and quality.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Many of those practicing in the fertilizer industry have found, as I have found, that surplus, economically priced prilled urea which is presently available on the world market is of a relatively small particle size, has low crushing strength, oftentimes contains quantities of small lumps or agglomerates (previously referred to as oversize) and fines or dust (previously referred to as undersize), and further, that such oversize and undersize is never present in consistent amounts. Pilot-plant tests have shown that when oversize and undersize particles were removed from the urea prills fed to the granulation drum, precise control of the granulation process including product size and quality was easily maintained; i.e., closely sized urea prills were fed into the granulation drum at the specified rate, onto which a specified rate of essentially anhydrous molten urea was sprayed, which produced a predetermined, closely sized granular urea product of high strength with other favorable properties.
It will become apparent to those skilled in this art who further read this disclosure that the process of the present invention and several embodiments of such process as for example, those illustrated in FIGS. 1 and 2 are very flexible. For example, by tailoring the feed rate and particle size of the urea-prill feed to the granulation drum for a specified molten urea rate and selecting the proper size product screen cloths, it is quite easy and convenient to produce products of several sizes to meet special applications and market requirments. It will also become apparent to those versed in this art that multigrade fertilizers such as X-X-X, X-X-O, and/or X-O-X can be produced by the process of the present invention by "overcoating" smaller particles of phosphatic, potassium, and/or blends of fertilizer particles such as diammonium phosphate (DAP), monoammonium phosphate (MAP), and muriate of potash (KCl) to produce multigrade fertilizers as is demonstrated in Example IV infra of this disclosure.
A typical application of the method illustrated in FIG. 2 supra would be that of properly retrofitting the process to an existing urea-production facility for the purpose of both producing a superior product and for increasing production. In the instance of a small facility having a urea-synthesis plant with a capacity of about 300 tons per day, a retrofitting, the facility could realize a maximum increase in production of about 65 percent without the added cost of increasing the capacity of the urea-synthesis plant. The increase in production would result from feeding purchased urea prills in the process. The total plant production would be dervied from 300 tons per day (dry basis) of urea solution from the existing urea-synthesis plant, 150 tons per day of persized urea prills fed to the rotary granulation drum, and about 45 tons per day oversize and undersize from the urea-prill sizing screen which would be recovered in the steam-heated dissolving tank, and as 75 to 77 percent solution, fed to the urea evaporator thereby increasing the essentially anhydrous molten urea feed rate to the granulation drum from 300 to 345 tons per day and increasing production from 300 to 495 tons per day.
In the method of the present invention, as illustrated in FIG. 1 supra, dust generated in the process was shown to be recovered in a dry collector, and as dust, makes up a portion of urea feed to the urea melter for processing into molten urea feed to the granulation drum. In some instances, those practicing this art may prefer to recover the generated dust in wet scrubbers utilizing the scrubber liquor produced in liquid fertilizer formulations or other applications. In other instances, those practicing the art of the embodiment illustrated in FIG. 2 may prefer to recover the generaed dust in dry collectors. The collected urea dust would then be recovered in the dissolving tank.
In pilot-plant tests, horizontally rotating screens were used for presizing of the urea-prill feed to the granulation drum and sizing the granules from the fluid-bed cooler. There are several screening systems available that would most probably perform these functions adequately.
It is without doubt that those who practice the art would prefer to perform some of the functions of this disclosure, for example, dust recovery, screening, and cooling of granulated particles by alternate means, all of which are within the scope and spirit of this disclosure--provided, of course, that such alternate means perform the functions of this disclosure within acceptable limits.
Those familiar with process and process equipment development procedures will realize, of course, that there are sometimes more than subtle differences in the design of pilot-plant and production-plant equipment. A case in point is the pilot-plant rotary granulation drum as illustrated in FIG. 3 which was designed with maximum flexibility in mind while a granulation drum for a production plant would not necessarily require such flexibility as for example, the multipurpose assembly which consists of the upper deflector pan, cooling-air distribution manifold, and lower deflector pan and located in the upper section of the granulation drum. The cooling-air distribution manifold was attached to the upper and lower deflector pan with hinges spaced along the length of the manifold. The hinges allowed flexiblity; i.e., the angle of the deflector pans could be adjusted during operation and without alterations. The dust shield was not attached to the cooling-air distribution manifold and was free to move up and down when adjustments to the angle of the upper deflector pan were made. The cooling-air distribution manifold could readily be detached and removed from the drum if necessary by disconnecting the inlet air duct and driving out the hinge pins.
In larger granulation drums, it may be found desirable to construct the multipurpose assembly as a unit to achieve greater structural strength. It may also be desirable that the cooling-air distribution manifold be constructed so that its cross-section is of other configurations such as that of a parallelogram. Additional deflector pans and cooling-air distribution manifolds may be installed in very large granulation drums, all of such variations should be considered to be within the scope and spirit of this disclosure.
Blouin in U.S. Pat. Nos. 3,991,225 and 3,877,415 supra has taught art of utilizing lifting flights and a deflector pan to form a homogeneous distribution of particles into a falling curtain in a granulation vessel onto which essentially anhydrous molten urea is sprayed thus improving granulation. Shirley in U.S. Pat. No. 4,213,924 supra and Shirley et al in U.S. Pat. No. 4,506,453 and 4,424,176 supra have further developed the art of urea granulation and heat transfer by both the rapid evaporation of water inside the granulation drum to cool the ventilation air flowing through the drum and by the use of the multiplicity of propeller-type fans to blow the air cooled by water evaporation onto the upper falling curtain of feed particles. It will be appreciated that the techniques of using propeller-type fans and water evaporation was not employed in the present invention. Although sound in theory, the propeller-type fans and water evaporation technology, as applied to urea granulation, proved difficult to maintain and operate in production-size granulation drums and, as a result, these features were not well accepted by the industry. The most serious problems encountered with the use of fans and water evaporation technology were that water often leaked from its piping and nozzles inside the drum and caused buildups on the drum shell; dust buildup on the blades of the propeller caused them to become unbalanced and break down; and perhaps most seriously, air blown by the fans did not effectively penetrate the dense falling curtain of feed particles to cool the free-falling particles behind the curtain. Instead, air from the fans, after striking the dense curtain, bypassed the curtain by flowing in the reverse direction underneath the upper deflector pans and fans toward the center of the drum and laterally along the curtain into the exhaust hood.
It can be seen from the cross-sectional view of FIG. 3 that the multipurpose assembly was designed and constructed so that the airflow from the cooling-air distribution manifold cannot bypass the falling curtain of feed particles. Since the manifold is attached and sealed to the top and bottom deflector pans and baffled at each end of the manifold (not shown), cooling air was positively forced through the curtain to provide cooling for the falling curtain of particles and the free-falling particles behind the curtain.
The present invention allows for the practice of several variations thereof, for example, airflow through the drum could either be made cocurrent as shown in FIG. 3 or countercurrent to the flow of granules through the drum with equal utility. Also, cooling air entering the feed end of the drum, as shown in FIG. 3, could enter from the discharge without loss of utility. Under almost all ambient conditions, refrigeration of cooling air would not be needed; however, it is conceivable that should a granulating plant of this type be located where the climate is extremely hot and humid, refrigeration and dehumidification of the cooling air would be required. These features, all of which are considered to fall within the scope and spirit of this disclosure, allow the practitioner of the present invention considerable freedom of design and application.
EXAMPLES
In order that those skilled in the art may better understand how the present invention can be practiced, the following examples are presented by way of illustration only and not necessarily by way of limitation since numerous variations thereof will occur and will undoubtedly be made by those skilled in the art without substantially departing from the true and intended scope and spirit of the present invention herein taught and disclosed.
It can be seen that the term size guide number (SGN) is used frequently in the following examples. SGN, which has widespread use in the fertilizer industry, is a dimensionless number that represents an average or median particle-size diameter of an aggregate of particles exposed in millimeters (mm) times (x) 100 and then rounded to the nearest 5. Thus, feed urea prills, granular urea, or other similar particles having an average diameter of 2.18 mm would have an SGN of 220. The SGN can be determined by plotting the values of the cumulative particle-size analysis in the form of a graph and selecting the midpoint of the curve or the SGN can be determined mathematically by the following equation. ##EQU1## where:
x=screen opening size in mm for the screen immediately above 50 percent as determinedd by cumulative particle-size analysis.
y=screen opening size in mm for the screen immediately below 50 percent of cumulative particle-size analysis.
HS=cumulative percent of particles retained on screen y.
LS=cumulative percent of particles retained on screen x.
For convenience to the reader, the tabulated data which reflects the operations of and results from the following examples, are presented together in Table I at the end of Example IV.
EXAMPLE I
Pilot-plant test 122 was one of a series of 19 tests totaling about 96 hours of operation made for the purpose of more clearly defining the parameters affecting the practice of the present invention. The specific purpose of pilot-plant test 122 was to produce a larger-than-standard-size granular urea product of high strength for direct application to such crops as wheat and rice where larger-than-standard-size granular urea is preferred. In this test, a very satisfactory large granular urea product (crushing strength =7 pounds for -7+8 Tyler mesh-size granules) was made at the production rate of 2,940 pounds per hour by the process illustrated in FIG. 1. Large presized urea prills, predominantly -7+9 Tyler mesh (SGN=260) which had a normal crushing strength of about 3 pounds (-7+8 Tyler mesh size), were fed to the granulation drum at the rate of 1,020 pounds per hour. Recycled undersize from the product screens was returned to the drum at the rate of 540 pounds per hour. Onto the falling curtain of solid feed in the drum (1,560 pounds per hour total) was sprayed essentially anhydrous molten urea at the rate of 1,920 pounds per hour. Granulation at the melt/prill weight ratio of 1.9 (melt/solids weight ratio=1.2) was considered very good. The large granular urea product, produced in test 122, and predominantly -6+8 Tyler mesh (SGN=275), was very round and smooth (sphericity=85%) with high crushing strength and other favorable properties. The 1,020-pound-per-hour urea-prill feed represents an increase in production rate of about 53 percent. Operating data and product characteristics are listed in Table I infra.
EXAMPLE II
The purpose of pilot-plant test 145 was to produce a small-size granular urea product suitable for sulfur coating for production of a controlled release nitrogen fertilizer of the size preferred by the fertilizer industry for use in lawn and garden fertilizer formulations. In test 145, a very satisfactory granular urea product was made at a production rate of 3,300 pounds per hour by the process as illustrated in FIG. 1. Small presized urea prills, predominantly -10+20 Tyler mesh (SGN=130), were fed to the granulation drum at the rate of 900 pounds per hour along with recycled undersize particles from the product screen at the rate of 690 pounds per hour. Molten urea was sprayed onto the falling curtain of feed particles in the drum at the rate of 2,400 pounds per hour producing a melt/prill weight ratio of 2.7 (melt/solids weight ratio=1.5). The product from test 145 was about 98 percent -8+12 Tyler mesh (SGN=180). It was very round and smooth (sphericity=94%) and had a crushing strength of 4 pounds for the -8+9 Tyler mesh-size granules. The product was proven to be an excellent substrate for sulfur coating. Operating data and product characteristics for test 145 are given in Table I infra. The urea-prill feed rate of 900 pounds per hour represents an increased production rate of about 37.5 percent.
EXAMPLE III
The purpose of pilot-plant tests 184-5, which were duplicate tests, was to produce a standard-size granular urea product at the production rate of 3,000 pounds per hour of the size that is preferred by the fertilizer industry for incorporating with other fertilizer components for production of bulk-blend fertilizer grades. Tests 184-5 were made using the process illustrated in FIG. 1 with the exception that wet scrubbers were used instead of a dry collector to recover urea dust generated during the tests. Low-quality, purchased urea feed prills were prescreened using screen cloths of 6 mesh and 12 mesh installed in the urea-prill feed screen to remove agglomerates, lumps, and dust. The sized urea prills were predominantly -8+12 Tyler mesh (SGN=190) and were fed to the granulation drum at the rate of 1,020 pounds per hour while recycled undersize particles from the product screen were returned to the drum at the rate of 1,860 pounds per hour. Urea melt was sprayed onto the falling curtain of solid feed particles at the rate of 1,980 pounds per hour or at the melt/prill weight ratio of 1.9 (melt/solids weight ratio=0.7). Very good granular urea product was produced in tests 184-5 which was about 97 percent -7+9 Tyler mesh (SGN=235). The product was very round and smooth (sphericity=85%) and had an average crushing strength of 7 pounds (-7+8 Tyler mesh size) with other favorble properties. Operating data and product characteristics are given in Table I infra. The urea prills fed to the granulation drum at the rate of 1,020 pounds per hour represent an increase in production rate of 51.5 percent.
EXAMPLE IV
The flexibility of the process of the present invention was well demonstrated in pilot-plant test UK-4. In this test, a satisfactory product of 31-0-21 grade (31% N-0% P 2 O s -21% K 2 O) was made at the production rate of 3,000 pounds per hour by "overcoating" small particles of muriate of potash (63% K 2 O) with molten urea (46.5% N). The method used in test UK-4 was the process illustrated in FIG. 1 of this disclosure with the exception that a wet scrubber system, instead of a dry collector, was used to recover process dust. Small, round potash particles, predominantly -8+14 Tyler mesh size (SGN=190), were fed to the granulation drum at the rate of 1,000 pounds per hour with recycled undersize particles from the product screen returned to the drum at the rate of 660 pounds per hour. Urea melt was sprayed on the falling curtain of solid feed particles in the drum at the rate of 2,000 pounds per hour (melt/potash weight ratio=2.0; melt/solids weight ratio=1.2). The granular 31-0-21 grade product produced in test UK-4 (100 percent -6+12 Tyler mesh size; SGN=220) was very round (sphericity=86%) and had a crushing strength of 4 pounds (-7+8 Tyler mesh size), which is considered adequate hardness though somewhat less than desired. Pilot-plant operating data and product characteristics of test UK-4 are presented in Table I below.
TABLE I______________________________________Urea-Granulation Pilot-Plant OperationData and Product Characteristics______________________________________Test No. 122 145 184-5 UK-4Test duration, h 6.0 6.4 8.7 3.2Production rate, lb/h 2,940 3,300 3,000 3,000Urea melterUrea-prill feed rate, 1,920 2,400 1,980 2,000lb/hChemical analysis, wt %Total N 46.5 46.5 46.3 46.5Biuret 0.3 1.2 0.7 0.6Conditioner Nil 0.3.sup.a 0.2.sup.a NilMoisture 0.1 0.1 0.3 0.2Melt concentration, wt % 99.9 99.9 99.7 99.8Conditioner added to 0.23.sup.b -- 0.6.sup.c --melt, wt %Granulation drumFeed rate, lb/hUrea melt 1,920 2,400 1,980 2,000Presized urea prills 1,020 900 1,020 --Size range, Tyler mesh -7 +9 -10 +20 -8 +12 --Size guide number 260 130 190 --Melt/prill wt ratio 1.9 2.7 1.9 --Presized potash particles -- -- -- 1,000K.sub.2 O, wt % -- -- -- 63Size range, Tyler mesh -- -- -- -8 +14Size guide number -- -- -- 190Recycled undersize 540 690 1,860 660Melt/solids wt ratio 1.2 1.5 0.7 1.2Cooling air, acfm 2,100 3,040 3,585 2,810Melt spraying pressure, 200 250 45 N/Alb/in.sup.2Rotation, r/min 6.5 5 6 11Melt spray nozzles, No. 14 17 7 11Process temperatures, °F.Granulation drumUrea melt sprayed 296 303 298 318Presized urea-prill feed 75 80 80 --Presized potash feed -- -- -- 73Recycled undersize feed 88 109 90 73Cooling air entering 72 74 80 68Granules exiting 214 216 208 173Process coolerGranules entering 214 216 208 173Granules exiting 102 110 119 125Product coolerProduct entering --.sup.d --.sup.d 119 --.sup.dProduct exiting --.sup.d --.sup.d 92 --.sup.dProduct characteristicsChemical analysis, wt %Total N 46.5 46.5 46.1 31.1K.sub.2 O -- -- 20.6Biuret 0.9 1.79 1.3 1.6Moisture 0.1 0.1 0.2 N/AConditioner 0.2.sup.b 0.3.sup.a 0.8.sup.e NilPhysical properties.sup.fBulk density, lb/ft.sup.3 47 48 48.5 54Angle of repose, degrees -- -- 24 24Sphericity, wt % 85 94 85 86Hardness, -7 +8 Tyler 7 4.sup.g 7 4mesh,lbSize range, Tyler mesh -6 +8 -8 +12 -7 +9 -6 +12Size guide number 275 180 235 220______________________________________ .sup.a Equivalent formaldehyde content in feed urea prills as purchased. .sup.b Equivalent formaldehyde content added to the urea melt as conditioning agent. .sup.c Equivalent content of calcium lignosulfonate added to the urea mel as conditioning agent. .sup.d Product was not further cooled. .sup.e Product contained 0.2% formaldehyde conditioner from feed prills and 0.6% calcium lignosulfonate conditioner added during test. .sup.f Physical properties determined by proceduees as outlined in TVA Bulletin Y147. .sup.g Value shown represents the crushing strength of -8 +9 Tyler meshsize granules instead of -7 +8 mesh size.
INVENTION PARAMETERS
After sifting and winnowing through the data supra as well as other results and operations of my new, novel, and improved technique and apparatus, including method and means for the effecting thereof, the operating variables, including the acceptable and preferred conditions for carrying out my invention, are summarized below.
TABLE II______________________________________Invention Parameters MostVariables Limits Preferred Preferred______________________________________FeedstockUrea meltConcentration, wt % 95-100 99-100 >99Temperature, °F. 275-315 278-305 286Urea prillsSize guide number.sup.a 85-200 150-190 180Size guide number.sup.b 85-300 225-275 260Size guide number.sup.c 85-150 100-135 125Granulation DrumMelt/prill wt ratio 1:1-40:1 2:1-3.5:1 2.5:1Melt/solids wt ratio 0.5:1-7:1 0.7:1-1.5:1 0.9:1-1.2:1Rotation, % of critical 15-40 17-25 20speedAir velocity through 25-200 50-150 100drum, ft/minProcess temperatures, °F.Urea melt to drum 275-315 278-305 286-290Presized urea prills to 25-160 45-100 60drumRecycled undersize to 50-160 75-140 115drumCooling air to drum 0-110 50-95 60-75Granules exiting drum 170-230 190-225 210-225Exhaust air from drum 100-190 120-150 130-140Granules exiting process 100-155 110-140 115-125coolerProduct to storage 60-110 85-105 90-100Product properties (urea)Chemical analysis, wt %Total N 45.5-46.5 46.0-46.4 46.3Biuret 0.2-3.0 0.2-1.5 0.2-0.7Moisture <0.1-0.3 <0.1-0.2 <0.1-0.1Conditioner 0-2 0.2-1.0 0.2-0.5Physical propertiesCrushing strength, lb (-7 4-8 6-8 7-8+8 Tyler mesh)Size rangeSize guide number.sup.a 200-240 215-235 215-225Size guide number.sup.b 235-600 250-395 275-300Size guide number.sup.c 100-200 160-190 170-180______________________________________ .sup.a For production of standardsize granular urea products. .sup.b For production of largerthan-standard-size granular urea products. .sup.c For production of smallerthan-standard-size granular urea products
While I have shown and described particular embodiments of my invention, modifications and variations will occur to those skilled in the art. I wish it to be understood, therefore, that the appended claims are intended to cover such modifications and variations which are within the true scope and spirit of my invention.
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The present invention teaches a technique and provides for apparatus eminently useful for producing closely sized, high-strength granular particulates from low-strength prills such as, for example, urea and ammoniu m nitrate which are nitrogen fertilizers, i.e., an essential plant nutrient. Advantages and benefits derived from the practice of the present invention relate to the production of closely sized high-strength particulates useful to the chemical fertilizer industry by virtue of their having favorable properties for custom fertilizer blending, direct applications, and as a substrate for sulfur coating to produce a controlled release fertilizer. Further advantages and benefits derived from the practice of the present invention relate to the utilization of low-cost surplus prills of low stren gth as feedstock in the production of the closely sized, high-strength granu lar particulates. Accordingly, the instant granulation process requires considerably less energy input than prior art granulation processes.
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BACKGROUND OF THE INVENTION
Self-watering flower pots, and the like, are well known in the art in relatively simply forms. U.S. Pat. No. 4,219,967 discloses a flower pot or plant holder equipped with a liquid storage reservoir in the base of said pot, which is connected by virtue of a relatively large wick through the bottom of the growing medium holder, to contact the growing medium and transmit moisture thereby.
U.S. Pat. No. 4,121,608 discloses the use of a separate reservoir, and a hose, the flow of liquid being regulated by the expansion of a wooden plug within a valve which is directly inserted into the growing medium, drawing moisture therefrom.
U.S. Pat. No. 4,223,837 discloses the use of a siphon operated liquid feed system from a reservoir and a float-regulated liquid level.
While all of the foregoing inventions operate, there remains a need for a more effective delivery system of liquids to the growing media of a plant which will not result in the over-watering or under-watering conditions which are common in the existing state of the art. Likewise, the current inventions all require frequent attention by virtue of evaporation losses, over-watering or inefficient liquid delivery systems.
The invention disclosed herein overcomes these limitations by use of a novel wick transmission system and support, and a feedback mechanism which regulates the liquid flow.
SUMMARY OF THE INVENTION
The invention provides an apparatus for the supply of water, nutrients or other liquid materials to the growing medium of potted plants. In particular, the invention comprises a purely mechanical and self-powered gravity feed system for the irrigation and feeding of plants, which includes a novel moisture feedback control system. The apparatus comprises a plant-containing vessel comprised of two distinct chambers, one filled with soil for the growing of the plant, and the other divided into three sub-chambers, one being a reservoir for water, one being a delivery passageway for water, and the third being a chamber containing a moisture feedback control system.
Liquid is delivered from a liquid storage chamber to the growing medium by virtue of a rigidly supported wick, which feeds a measured volume of water by gravity to the growing medium. The wick and its support may be enclosed with a clear cover to allow visual observation of the level of the liquid in the reservoir, by virtue of the standing height of the wick support.
A bi-expandable strip is located in a chamber immediately adjacent to the soil and vented to the soil chamber, thereby creating an atmosphere in said chamber holding the bi-expandable strip which is either moist or dry depending on the condition of the soil. When moist, the bi-expandable strip deforms, causing the upper end of said strip to apply pressure to the wick support, fixing the wick support in position and thereby slowing the delivery of liquid to the growing medium. When the growing medium is dry, the bi-expandable stip deforms in an opposite direction, releasing the wick support and allowing the wick assembly to retract into the liquid storage chamber, thereby increasing the flow of liquid to the medium.
Preferably, the bi-expandable strip is adjusted by means of a variable fulcrum, which regulates the deformable length of the bi-expandable strip, thereby establishing the moisture level in the chamber in which said bi-expandable strip is located, at which the strip effectively regulates the movement of the wick support assembly.
In addition, located within the liquid delivery chamber of the invention is a moisture flow indicator means, which is essentially a movable and balanced indicator, one end of which is mechanically connected to a sponge-like substance, which absorbs moisture, and accordingly, increases in weight. The flow of water to the soil is accordingly interdicted by the presence of a small moisture absorbing sponge attached to the pivotable indicator. When the moisture absorbing sponge is wet, it is of sufficient weight as to draw the flow indicator into a more or less upright position. When the sponge material is dry, the pivotable indicator returns to a more or less horizontal position, indicating the absence of water flow through the overall system.
The three sub-chambers containing the liquid delivery system and feedabck control may be manufactured as a unitary part of the chamber in which the growing medium is contained, or may be manufactured as a separate unit, suitable for attachment to an existing flowerpot or planter.
BRIEF DESCRIPTION OF THE DRAWING
Sheet 1 consists of three figures and sheet 2 consists of three figures.
FIG. 1 is a perspective view of the plant container and automatic watering apparatus combination, with a portion of the container shown cut away to show the relationship of the liquid reservoir and the liquid delivery chamber.
FIG. 2 is a cross-sectional view, showing the liquid reservoir and liquid delivery chambers, together with the flow indicator mechanism.
FIG. 3 is a detail of the flow indicator flag and pivot point.
FIG. 4 is a cross-sectional view of the entire liquid delivery assembly, showing the relationship of the feedback control chamber and mechanism to the balance of the system components.
FIG. 5 is a detailed view of the method of operation of the bi-expandable strip, and its relationship to the wick support tube.
Finally, FIG. 6 is a cut away perspective view of the wetness feedback control components.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Initially, it should be noted that while the drawings depict a unified structure for the automatic watering system described herein and the plant growing medium holder, and in fact, it is convenient to manufacture the compounds thus, by no means is it necessary to permanently attach the reservoirs of the automatic watering system to the medium holder. In fact, for large commercial installations, such as planters and the like, a series of movable automatic watering system apparatus can be attached to the growing medium container by suspending said apparatus from the edge of the growing medium container wherein planting it at some point in the surface of the growing medium. In both configurations, the invention functions in exactly the same fashion, the only difference being the absence of a permanent attachment between the automatic watering system reservoirs and chambers, and the medium holder.
Referring now to FIG. 1, the invention pertains to an apparatus for attachment to a plant-growing medium container (1), either permanently or non-permanently, comprising a liquid reservoir chamber, a liquid delivery passageway and a feedback control chamber, said reservoir and chambers being colocated with the growing medium and providing a regulated flow of liquid (for example, water or solutions of water or nutrients) to the soil or growing medium (2) in which the plant (3) is growing.
Referring now to FIG. 4, the growing medium container (1) is filled with soil, peat, mulch or other natural or artificial medium (2) in which are located one or more growing plants. Liquid reservoir chamber (9) is provided, and is separated from the liquid delivery chamber (13) by chamber wall (21). The third chamber in the automatic watering system apparatus is the feedback control chamber (15). Reservoir (9), chamber (13) and chamber (15) together contain the remaining components which comprise the invention herein described.
In the preferred embodiment, liquid is added to chamber (9) through opening (8), which is provided with a removable stopper (17). Contained within chamber (9) is a float guide (10), consisting of a cylinder of slightly larger inside diameter than the outside diameter of cylindrical float (11). The float guide cylinder (10) is connected to the liquid reservoir (9) by opening (12), insuring that the liquid level in the float guide (10) is the same as the liquid level in the balance of the chamber (9). The float guide (10) is also equipped with vent hole (12a) to allow full equalization of pressure. Immediately adjacent to reservoir (9) is liquid delivery chamber (13), which is connected to the growing medium portion of the vessel by virtue of opening (14).
A wick support tube in the shape of an inverted U (6) contains a wick (5) composed of suitable material to attract and allow the transmission of liquid. The wick support tube is inserted in openings (6a), thereby placing one end of the wick support tube into the liquid reservoir (9), and the other end of said wick support tube into the liquid delivery chamber (13). On the end of said tube disposed within reservoir (9), there is placed a float (11), which is roughly cylindrical in shape, and containing an opening (11a) in the center of said float (11), said opening (11a) being round, and of such diameter as to create a snug fit between the wick support tube (6) and the float (11). This fit is a sliding fit, allowing the regulation of the height of the wick support tube (6), thereby regulating the depth of the wick support tube (6) in relation to the fluid contained within reservoir (9). Said wick support tube feeds, by gravity, liquid to the reservoir (13), said liquid moistening the soil (2) contained within the growing medium chamber of the planter or flowerpot (1). Inasmuch as the flow of liquid from the reservoir (9) to the delivery chamber (13) is a function of the length of the columns of liquid supported by the wick (5) contained within the wick support (6), the rate of flow of the liquid can also be adjusted by sliding the float (11) upward or downward upon wick support (6). In the preferred embodiment of the invention, the clearance between the cylindrical float (11) and the float guide cylinder (10) is typically 0.5 millimeters or less. Manually depressing the float guide (6) in a downward direction forces the cylindrical float (11) into the float guide cylinder (10), temporarily increasing the fluid pressure inside the float guide cylinder (10), directing fluid forcibly into the wick (5) through the wick support (6), thereby priming the system to commence operation.
To insure proper functioning of the wick delivery system, a vent (6b) is provided in wick support (6).
Referring now to FIGS. 5 and 6, contained within the feedback control chamber (15) is a bi-expandable strip (16), which consists of a flexible L-shaped pawl (16a) to which is attached a material, such as balsa wood, with a substantially different coefficient of expansion (16b). The lower end of said bi-expandable strip is secured to the floor of chamber (15) by insertion to slot (20). Chamber (15) is equipped with opening (19), allowing the moisture level of the growing medium (2) to affect the moisture level of the atmosphere contained within chamber (15).
The upper end of bi-expandable strip (16) passes through opening (18) in the top of the apparatus, allowing the end of the pawl (16) to contact the wick support (6) when the pawl (16) is moist. In the event that a wick support cover is installed, an opening is placed in the cover to allow the pawl to contact the wick support.
As the atmosphere contained within chamber (15) becomes dry, the layer (16b) of the bi-expandable strip contracts, resulting in the deformation of pawl (16), away from the wick support (6). Normally, the wick support (6) is suspended in the fluid contained within reservoir (9) based on the float height setting of float (11). In this configuration, a regular supply of liquid is provided through wick (5) to liquid delivery chamber (13). However, when the moisture level of the atmosphere in chamber (15) increases, layer (16b) of the pawl (16) expands, flexing the pawl (16) into a position toward wick support (6). The contact of pawl (16) against wick support (6) results in the fixation of wick support (6), preventing wick support (6) from any further downward movement, decreasing the flow of liquid from reservoir (9) to liquid delivery chamber (13) and subsequently to the soil.
Regulation of the action of pawl (16) is effected by a variable fulcrum assembly (17). Said variable fulcrum (17) is equipped with a cylindrical end piece (17a) disposed between the wall of feedback control chamber (15) and bi-expandable strip (16). The remaining portion of variable fulcrum (17) comprises a rigid handle, the upper portion of which protrudes through an opening above the level of the plant containing vessel. The upper end of said fulcrum (17) is equipped with graduations (22), to indicate the height at which the fulcrum is operating on the bi-expandable strip (16). Raising the variable fulcrum (17) decreases the operating length of pawl (16), thereby making the overall operation of the apparatus less sensitive to moisture, and increasing the flow of liquid to the growing medium. Lowering the fulcrum (17) increases the amount of travel allowed by pawl (16), thereby making the apparatus more sensitive, and reducing the amounts of moisture to be fed to the growing medium.
Referring to FIGS. 2 and 3, to monitor the operation of the system more precisely, a flow indicator (26), mounted on a pivot point (27) is equipped with a flow indicator flag (28), cast or painted a highly contrasting color. The end of said pivoting flag disposed opposite the brightly colored indicator is attached to a rod (25), of suitable length to dispose the lower end of said rod (25) below the delivery end of the wick support tube (6), said rod being equipped with a semi-rigid, water absorbant material such as sponge, said semi-rigid water absorbant material (24) being attached to the end of the rod (25) oppositely disposed the connecting point of said rod to the pivotable indicator (26). The flow of water from the delivery end of wick support (6), located within the liquid delivery chamber (13) causes the moisture absorbing material (24) to become saturated, and consequently, heavier, causing a downward force on one end of the flow indicator (26) hereby raising the opposite end of said flow indicator (28) to a more or less vertical position. The absence of water flow of liquid flow to liquid delivery chamber (13) results in the drying of material (24), which, becoming lighter, allows the indicator (26) to pivot to a more or less horizontal position. By this means, the correct operation of the liquid delivery system can be visibly confirmed.
The invention thus described provides means for continuous delivery of liquids to a plant growing medium at a controlled rate, as well as means for indicating the level of liquid in the supply reservoir. While having thus described my invention in detail, it should be noted that many variations may be made therein without substantially deviating from the function, utility and operation herein described, and which would nevertheless be contemplated within the terms of the claims herein stated.
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An apparatus for the delivery of water, nutrients or other liquid materials to the growing medium of potted plants, including a refillable chamber for the storage of the liquid, and means for attachment of the chamber to the vessel in which the growing medium is maintained. The chamber is equipped with a rigidly supported wick in the shape of an inverted U, one end of which is equipped with a float support, holding the wick in the liquid storage chamber. This allows adjustment of the depth of the wick into the chamber. The other end of the wick is inserted in a rigid passageway co-located with the growing medium. The apparatus is also equipped with an adjustable moisture-sensitive brake mechanism, regulating the movement of the wick support in relation to the liquid level in the refillable chamber thereby regulating the flow of liquid from the refillable chamber to the growing medium.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority of German application No. 102006047963.7 DE filed Oct. 10, 2006, which is incorporated by reference herein in its entirety.
FIELD OF INVENTION
[0002] The invention relates to a method for operating a hearing aid consisting of a single hearing device or two. The invention relates further to a corresponding hearing aid or hearing device.
BACKGROUND OF INVENTION
[0003] When we listen to someone or something, interference noise or undesired acoustic signals are everywhere present that interfere with the voice of someone opposite us or with a desired acoustic signal. People with a hearing impairment are especially susceptible to such interference noise. Background conversations, acoustic disturbance from digital devices (cell phones), or noise from automobiles or other ambient sources can make it very difficult for a hearing-impaired person to understand a wanted speaker. A reduction of the noise level in an acoustic signal coupled with an automatic focusing on a desired acoustic-signal component can significantly improve the efficiency of an electronic speech processor of the type used in modern hearing aids.
[0004] Hearing aids have very recently been introduced that employ digital signal processing. They contain one or more microphones, A/D converters, digital signal processors, and loudspeakers. The digital signal processors usually divide the incoming signals into a plurality of frequency bands. An amplification and processing of signals can be individually adjusted within each band in keeping with requirements for a specific wearer of the hearing aid in order to improve a specific component's intelligibility. Further available in connection with digital signal processing are algorithms for minimizing feedback and interference noise, although they have significant disadvantages. What is disadvantageous about the currently employed algorithms for minimizing interference noise is, for example, the maximum improvement they can achieve in hearing-aid acoustics when speech and background noise are located within the same frequency region, which renders them incapable of distinguishing between spoken language and background noise. (See also EP 1 017 253 A2)
[0005] That is one of the most frequently occurring problems in acoustic signal processing, namely filtering out one or more acoustic signals from among different such signals that overlap. The problem is referred to also as what is termed the “cocktail party problem”. All manner of different sounds including music and conversations therein merge into an indefinable acoustic backdrop. People nevertheless generally do not find it difficult to hold a conversation in such a situation. It is therefore desirable for hearing-aid wearers to be able to converse in just such situations like people without a hearing impairment.
[0006] Within acoustic signal processing there exist spatial (directional microphone, beam forming, for instance), statistical (blind source separation, for instance), and hybrid methods which, by means of algorithms and otherwise, are able to separate out one or more sound sources from among a plurality of simultaneously active such sources. Thus by means of statistical signal processing performed on at least two microphone signals, blind source separation enables source signals to be separated without prior knowledge of their geometric arrangement. When applied to hearing aids, that method has advantages over conventional approaches based on a directional microphone. With said type of BSS (Blind Source Separation) method it is inherently possible with n microphones to separate up to n sources, meaning to generate n output signals.
[0007] Known from the relevant literature are blind source separation methods wherein sound sources are analyzed by analyzing at least two microphone signals. A method of said type and a corresponding device therefore are known from EP 1 017 253 A2, the scope of whose disclosure is expressly to be included in the present specification. Relevant links from the invention to EP 1 017 253 A2 are indicated chiefly at the end of the present specification.
[0008] In a specific application for blind source separation in hearing aids, that requires two hearing devices to communicate (analyzing of at least two microphone signals (right/left)) and both hearing devices' signals to be evaluated preferably binaurally, which is performed preferably wirelessly. Alternative couplings of the two hearing devices are also possible in an application of said type. A binaural evaluating of said kind with a provisioning of stereo signals for a hearing-aid wearer is disclosed in EP 1 655 998 A2, the scope of whose disclosure is likewise to be included in the present specification. Relevant links from the invention to EP 1 655 998 A2 are indicated at the end of the present specification.
[0009] The controlling of directional microphones for performing a blind source separation is subject to equivocality once a plurality of competing useful sources, for example speakers, are presented simultaneously. While blind source separation basically allows the different sources to be separated, provided they are spatially separate, the potential benefit of a directional microphone is reduced by said equivocality, although a directional microphone can be of great benefit in improving speech intelligibility specifically in such scenarios.
SUMMARY OF INVENTION
[0010] The hearing aid or, as the case may be, the mathematical algorithms for blind source separation is/are basically faced with the dilemma of having to decide which of the signals produced through blind source separation can be forwarded to the algorithm user, meaning the hearing-aid wearer, to greatest advantage. That is basically an insoluble problem for the hearing aid because the choice of desired acoustic source will depend directly on the hearing-aid wearer's momentary will and hence cannot be available to a selection algorithm as an input variable. The choice made by said algorithm must accordingly be based on assumptions about the listener's likely will.
[0011] The prior art proceeds from the hearing-aid wearer's preferring an acoustic signal from a 0° direction, meaning from the direction in which he/she is looking. That is realistic insofar as the hearing-aid wearer would in an acoustically difficult situation look toward his/her current conversation partner in order to obtain further cues (for example lip movements) for enhancing said partner's speech intelligibility. The hearing-aid wearer will, though, consequently be compelled to look at his/her conversation partner so that the directional microphone will produce an enhanced speech intelligibility. That is annoying particularly when the hearing-aid wearer wishes to converse with precisely one person, which is to say is not involved in communicating with a plurality of speakers, and does not always wish/have to look at his/her conversation partner.
[0012] Furthermore, there is to date no known technical method for making a “correct” choice of acoustic source or, as the case may be, one preferred by the hearing-aid wearer, after source separating has taken place.
[0013] On the assumption that spoken language is of more interest to hearing-aid wearers than non-verbal acoustic signals, a more flexible acoustic-signal selection method can be formulated that is not limited by a geometric acoustic-source arrangement. An object of the invention is therefore to disclose an improved method for operating a hearing aid, and an improved hearing aid. Which of the electric output signals resulting from a source separation, in particular a blind source separation, is acoustically routed to the hearing-aid wearer is especially an object of the invention. It is hence an object of the invention to discover which is very probably a preferred acoustic speech source for the hearing-aid wearer.
[0014] The invention therein provides for performing a feature analysis of separated acoustic signals, once a source separation has taken place, with the aim of the hearing aid's selecting the acoustic source or sources very probably containing spoken language as the acoustic speech source or sources that will be offered to the hearing-aid wearer. The hearing-aid wearer can then decide whether he/she wants said source or sources or not, which can be indicated by means of any input device or a voice-recognition means in or on the hearing aid or a remote control for the hearing aid. It can also be done in an automated manner by the hearing aid (see below).
[0015] A method for operating a hearing aid is inventively provided wherein for tracking and selectively amplifying an acoustic speech source or electric speech signal a signal-processing means of the hearing aid determines and assigns preferably for all electric acoustic signals available to it a probability that they contain spoken language. The acoustic source or sources most probably containing speech will be tracked by the signal-processing means and taken particularly into account in an acoustic output signal of the hearing aid.
[0016] Further inventively provided is a hearing aid wherein electric acoustic signals can be allocated a respective probability of containing spoken language by an acoustic module (signal-processing means) of the hearing aid. The acoustic module selects therefrom at least one electric speech signal that can be taken particularly into account in an output sound of the hearing aid.
[0017] It is inventively possible, depending on the number of microphones in the hearing aid, to select one or more acoustic speech sources within the ambient sound and emphasize it/them in the hearing aid's output sound. It is possible therein to flexibly adjust a volume of the acoustic speech source or sources in the hearing aid's output sound.
[0018] In a preferred exemplary embodiment of the invention the signal-processing means has an unmixer module that operates preferably as a device for blind source separation for separating the acoustic sources within the ambient sound. The signal-processing means further has a post-processor module which, when an acoustic source very probably containing speech has been detected, will set up a corresponding “speech” operating mode in the hearing aid. The signal-processing means can further have a pre-processor module—whose electric output signals are the unmixer module's electric input signals—which standardizes and conditions electric acoustic signals originating from microphones of the hearing aid. As regards the pre-processor module and unmixer module, reference is made to EP 1 017 253 A2 paragraphs [0008] to [0023].
[0019] In a preferred exemplary embodiment of the invention the hearing aid or signal-processing means or post-processor module performs a feature analysis of the electric acoustic signals to the effect that for each of the electric acoustic signals a probability that it contains spoken language information is determined simultaneously and chiefly the electric acoustic signal or signals most probably containing speech will then be fed out by the signal-processing means or post-processor module to a listening means or loudspeaker of the hearing aid, which listening means or loudspeaker will convert the electric acoustic signals into analog sound information.
[0020] A source separation method for acoustic signals, in particular a blind source separation method, is inventively expanded to include a feature-analysis means that determines the probability that speech is contained in the separated source signals. Proceeding from the probabilities determined of containing speech, the acoustic source or sources most probably containing speech will be selected and routed to the hearing-aid wearer. What is therein advantageous is automatable selecting of the acoustic-source signal or signals for which speech intelligibility is at a maximum. Interference signals containing no speech are preferably not focused. Speech signals (too) disrupted by interference signals will contain speech less probably than will undisrupted speech signals and so are likewise not be preferred. The method is based on the assumption that speech and the understanding thereof are most important for the hearing-aid wearer. The acoustic source is therein selected preferably independently of a direction of incidence relative to the hearing aid. It is, though, possible to use the direction of incidence or a volume of the respective acoustic source as a further selection criterion for the signal-processing means or the post-processor module.
[0021] Additional preferred exemplary embodiments of the invention will emerge from the other dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The invention is explained in more detail below with the aid of exemplary embodiments and with reference to the attached drawing.
[0023] FIG. 1 is a block diagram of a hearing aid according to the prior art having a module for a blind source separation;
[0024] FIG. 2 is a block diagram of an inventive hearing aid having an inventive signal-processing means in the act of processing an ambient sound having two acoustically mutually independent acoustic sources; and
[0025] FIG. 3 is a block diagram of a second exemplary embodiment of the inventive hearing aid in the act of simultaneously processing three acoustically mutually independent acoustic sources in the ambient sound.
DETAILED DESCRIPTION OF INVENTION
[0026] Within the scope of the invention ( FIGS. 2 & 3 ), the following speaks mainly of a BSS module that corresponds to a module for a blind source separation. The invention is not, though, limited to a blind source separation of said type but is intended broadly to encompass source separation methods for acoustic signals in general. Said BSS module is therefore referred to also as an unmixer module.
[0027] The following speaks also of a “tracking” of an electric speech signal by a hearing-aid wearer's hearing aid. What is to be understood thereby is a selection made by a hearing aid or by a signal-processing means of the hearing aid or by a post-processor module of the signal-processing means of one or more electric speech signals that are electrically or electronically selected by the hearing aid from other acoustic sources in the ambient sound and which are rendered in a manner amplified with respect to the other acoustic sources in the ambient sound, which is to say in a manner experienced as louder for the hearing-aid wearer. Preferably no account is taken by the hearing aid of a position of the hearing-aid wearer in space, in particular a position of the hearing aid in space, which is to say a direction in which the hearing-aid wearer is looking, while the electric speech signal is being tracked.
[0028] FIG. 1 shows the prior art as disclosed in EP 1 017 253 A2 (see therein paragraph [0008]ff). A hearing aid 1 therein has two microphones 200 , 210 , which can together form a directional microphone system, for generating two electric acoustic signals 202 , 212 . A microphone arrangement of said type gives the two electric output signals 202 , 212 of the microphones 200 , 210 an inherent directional characteristic. Each of the microphones 200 , 210 picks up an ambient sound 100 which is an assemblage of unknown, acoustic signals from an unknown number of acoustic sources.
[0029] The electric acoustic signals 202 , 212 are in the prior art mainly conditioned in three stages. The electric acoustic signals 202 , 212 are in a first stage pre-processed in a pre-processor module 310 for improving the directional characteristic, starting with standardizing the original signals (equalizing the signal strength). A blind source separation takes place at a second stage in a BSS module 320 , with the output signals of the pre-processor module 310 being subjected to an unmixing process. The output signals of the BSS module 320 are thereupon post-processed in a post-processor module 330 in order to generate a desired electric output signal 332 serving as an input signal for a listening means 400 or a loudspeaker 400 of the hearing aid 1 and to deliver a sound generated thereby to the hearing-aid wearer. According to the specification in EP 1 017 253 A2, steps 1 and 3, meaning the pre-processor module 310 and post-processor module 330 , are optional.
[0030] FIG. 2 now shows a first exemplary embodiment of the invention wherein located in a signal-processing means 300 of the hearing aid 1 is an unmixer module 320 , referred to below as a BSS module 320 , connected downstream of which is a post-processor module 330 . A pre-processor module 310 can herein again be provided that appropriately conditions or, as the case may be, prepares the input signals for the BSS module 320 . Signal processing 300 preferably takes place in a DSP (Digital Signal Processor) or an ASIC (Application Specific Integrated Circuit).
[0031] It is assumed in the following that there are two mutually independent acoustic 102 , 104 or, as the case may be, signal sources 102 , 104 in the ambient sound 100 , with one of said acoustic sources 102 being a speech source 102 and the other acoustic source 104 being a noise source 104 . The acoustic speech source 102 is to be selected and tracked by the hearing aid 1 or signal-processing means 300 and is to be a main acoustic component of the listening means 400 so that an output sound 402 of the loudspeaker 400 mainly contains said signal ( 102 ).
[0032] The two microphones 200 , 210 of the hearing aid 1 each pick up a mixture of the two acoustic signals 102 , 104 —indicated by the dotted arrow (representing the preferred, acoustic signal 102 ) and by the continuous arrow (representing the non-preferred, acoustic signal 104 )—and deliver them either to the pre-processor module 310 or immediately to the BSS module 320 as electric input signals. The two microphones 200 , 210 can be arranged in any manner. They can be located in a single hearing device 1 of the hearing aid 1 or be arranged on both hearing devices 1 . It is moreover possible, for instance, to provide one or both microphones 200 , 210 outside the hearing aid 1 , for example on a collar or in a pin, so long as it is still possible to communicate with the hearing aid 1 . That also means that the electric input signals of the BSS module 320 do not necessarily have to originate from a single hearing device 1 of the hearing aid 1 . It is, of course, possible to implement more than two microphones 200 , 210 for a hearing aid 1 . A hearing aid 1 consisting of two hearing devices 1 preferably has a total of four or six microphones.
[0033] The pre-processor module 310 conditions the data for the BSS module 320 which, depending on its capability, for its part forms two separate output signals from its two, in each case mixed input signals, with each of said output signals representing one of the two acoustic signals 102 , 104 . The two separate output signals of the BSS module 320 are input signals for the post-processor module 330 , in which it is then decided which of the two acoustic signals 102 , 104 will be fed out to the loudspeaker 400 as an electric output signal 332 .
[0034] The post-processor module 330 for that purpose (see also FIG. 3 ) performs a feature analysis of the electric acoustic signals 322 , 324 in parallel, with a probability being determined for each of said electric acoustic signals 322 , 324 that it contains human speech. The post-processor module 330 then selects the acoustic signal 322 having the highest inherent probability of containing speech, and delivers said electric acoustic signal 322 in an amplified manner as an electric acoustic output signal 332 (corresponds basically to the electric acoustic signal 322 ) to the loudspeaker 400 .
[0035] FIG. 3 shows the inventive method and the inventive hearing aid 1 in the act of processing three (n=3) acoustic signal sources s 1 (t), s 2 (t), s n (t) which, in combination, form the ambient sound 100 . Said ambient sound 100 is picked up in each case by three microphones, which each feed out an electric microphone signal x 1 (t), x 2 (t), x n (t) to the signal-processing means 300 . Although the signal-processing means 300 herein has no pre-processor module 310 , it can preferably contain one. (That applies analogously also to the first exemplary embodiment of the invention). It is, of course, also possible to process n acoustic sources s simultaneously via n microphones x, which is indicated by the dots ( . . . ) in FIG. 3 .
[0036] The electric microphone signals x 1 (t), x 2 (t), x n (t) are input signals for the BSS module 320 , which separates the acoustic signals respectively contained in the electric microphone signals x 1 (t), x 2 (t), x n (t) according to acoustic sources s 1 (t), s 2 (t), s n (t) and feeds them out as electric output signals s′ 1 (t), s′ 2 (t), s′ n (t) to the post-processor module 330 .
[0037] In the following, two electric acoustic signals, namely s′ 1 (t) and s′ n (t) (corresponding in this exemplary embodiment very largely to the acoustic sources s 1 (t) and s n (t)), contain sufficient speech information. That means that the hearing aid 1 is rendered at least adequately capable of delivering an acoustic signal s′ 1 (t), s′ n (t) of said type to the hearing-aid wearer in such a way that he/she will be able to interpret the information contained therein adequately correctly, meaning will understand speech information contained therein at least adequately. It is further possible when a multiplicity of acoustic signals s′ 1 (t), s′ n (t) containing adequate speech information are present to select only those whose quality is the best or which the hearing-aid wearer prefers. The third acoustic signal s′ 2 (t) (corresponding in this exemplary embodiment very largely to the acoustic source s 2 (t)) contains no or hardly any usable speech information.
[0038] A feature analysis of the electric acoustic signals s′ 1 (t), s′ 2 (t), s′ n (t) is then performed within the post-processor module 330 and a probability p 1 (t), p 2 (t), p n (t) determined separately for each electric acoustic signal s′ 1 (t), s′ 2 (t), s′ n (t) that it contains human speech information. The post-processor module 330 then selects the electric acoustic signal or, as in this case, the electric acoustic signals s′ 1 (t), s′ n (t) with the highest probabilities of containing speech, and makes them available to the loudspeaker 400 in the form of the output signal 332 .
[0039] It is, of course, also possible in the case of the second exemplary embodiment of the invention to render only one or three or more acoustic speech sources s 1 (t), s n (t) in an amplified manner.
[0040] The feature analysis in the post-processor module 330 can inventively always run concurrently in the background of the hearing aid 1 and be initiated when an electric speech signal 322 ; s′ 1 (t), s′ n (t) arises. It is also possible for the inventive feature analysis to be called up by the hearing-aid wearer. That means that the “speech” operating mode of the hearing aid 1 will be established initiated from an input device that can be called up or actuated by the hearing-aid wearer. The input device can therein be a control element on the hearing aid 1 and/or a control element on a remote control of the hearing aid 1 , for example a pushbutton or switch (not shown in the Figs.). It is possible, moreover, for the input device to be embodied as a voice-control means having an assigned speaker-recognition module attuned to a voice of the hearing-aid wearer, with the input device being embodied at least partially in the hearing aid 1 and/or at least partially in the remote control of the hearing aid 1 .
[0041] It is furthermore possible to by means of the hearing aid 1 obtain additional information about which of the electric speech signals 322 ; s′ 1 (t), s′ n (t) are preferably rendered to the hearing-aid wearer as output sound 402 , s″(t). That can be an angle at which the corresponding acoustic source 102 , 104 ; s 1 (t), s 2 (t), s n (t) impinges on the hearing aid 1 , with certain such angles being preferred. Thus, for example, the 0° direction in which the hearing-aid wearer is looking or his/her 90° lateral direction can be preferred. The electric speech signals 322 ; s′ 1 (t), s′ n (t) can furthermore be weighted to the effect—even apart from the different probabilities p 1 (t), p 2 (t), p n (t) that they contain speech information (that of course applies to all exemplary embodiments of the invention)—as to whether one of the electric speech signals 322 ; s′ 1 (t), s′ n (t) is predominant or a relatively loud electric speech signal 322 ; s′ 1 (t), s′ n (t).
[0042] It is inventively not necessary to perform the feature analysis of the electric acoustic signals 322 ; 324 ; s′ 1 (t), s′ 2 (t), s′ n (t) within the post-processor module 330 . It is also possible, for example for reasons of speed, to have the feature analysis performed by another module of the hearing aid 1 and to leave just selecting of the electric acoustic signal or signals 322 , 324 ; s′ 1 (t), s′ 2 (t), s′ n (t) having the highest probability or probabilities p 1 (t), p 2 (t), p n (t) of containing speech to the post-processor module 330 . With that kind of exemplary embodiment of the invention, said other module of the hearing aid 1 ought, by definition, to be included in the post-processor module 330 , meaning in that kind of exemplary embodiment the post-processor module 330 will encompass said other module.
[0043] The present specification relates inter alia to a post-processor module 20 as in EP 1 017 253 A2 (the reference numerals are those given in EP 1 017 253 A2), in which module one or more speakers for an electric output signal of the post-processor module 20 is/are selected by means of a feature analysis and rendered therein at least amplified. See in that regard also paragraph [0025] in EP 1 017 253 A2. The pre-processor module and the BSS module can in the inventive case furthermore be structured like the pre-processor 16 and the unmixer 18 in EP 1 017 253 A2. See in that regard in particular paragraphs [0008] to [0024] in EP 1 017 253 A2.
[0044] The invention furthermore links to EP 1 655 998 A2 in order to make stereo speech signals available or, as the case may be, enable a binaural acoustic provisioning with speech for a hearing-aid wearer. The invention (notation according to EP 1 655 998 A2) is herein connected downstream of the output signals z 1 , z 2 respectively for the right(k) and left(k) of a second filter device in EP 1 655 998 A2 (see FIGS. 2 and 3 ) for accentuating/amplifying the corresponding acoustic source. It is furthermore possible to apply the invention in the case of EP 1 655 998 A2 to the effect that it will come into play after the blind source separation disclosed therein and ahead of the second filter device. That means that a selection of a signal y 1 (k), y 2 (k) will therein inventively take place (see FIG. 3 in EP 1 655 998 A2).
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A “speech” operating mode is established by a signal processor of a hearing aid for tracking and selecting an acoustic speech source in an ambient sound. The electric acoustic signals are generated by the hearing aid from the ambient sound that has been picked up, from which signals an electric speech signal very probably containing speech is identified and selected by the signal-processor, and the electric speech signal is selectively taken into account in an output sound of the hearing aid in such a way that it will for the hearing-aid wearer acoustically at least be prominent compared with another acoustic source and consequently be better perceived by the hearing-aid wearer.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 13/278,341 filed on Oct. 21, 2011, which is a continuation of U.S. patent application Ser. No. 12/474,802 filed on May 29, 2009, now U.S. Pat. No. 8,088,130 issued on Jan. 3, 2012; which is a continuation-in-part of: (1.) U.S. patent application Ser. No. 11/541,506 filed on Sep. 29, 2006, now U.S. Pat. No. 7,601,165 issued on Oct. 13, 2009; (2.) U.S. patent application Ser. No. 11/541,505 filed on Sep. 29, 2006, now U.S. Pat. No. 7,658,751 issued on Feb. 9, 2010; (3.) U.S. patent application Ser. No. 12/014,399 filed on Jan. 15, 2008, now U.S. Pat. No. 7,909,851 issued on Mar. 22, 2011; (4.) U.S. patent application Ser. No. 12/014,340 filed on Jan. 15, 2008, now U.S. Pat. No. 7,905,904 issued on Mar. 15, 2011; (5.) U.S. patent application Ser. No. 11/935,681 filed on Nov. 6, 2007, now U.S. Pat. No. 7,905,903 issued on Mar. 15, 2011; (6.) U.S. patent application Ser. No. 11/869,440 filed on Oct. 9, 2007, now U.S. Pat. No. 7,857,830 issued on Dec. 28, 2010; (7.) U.S. patent application Ser. No. 11/784,821 filed on Apr. 10, 2007; (8.) U.S. patent application Ser. No. 11/347,661 filed on Feb. 3, 2006, now U.S. Pat. No. 7,749,350 issued on Jul. 6, 2010; (9.) U.S. patent application Ser. No. 11/347,662 filed on Feb. 3, 2006, now abandoned.
This application is also a continuation-in-part of U.S. patent application Ser. No. 13/412,105 filed on Mar. 5, 2012, which is a continuation-in-part of: (1.) U.S. patent application Ser. No. 12/196,405 filed on Aug. 22, 2008, now U.S. Pat. No. 8,128,658 issued on Mar. 6, 2012; (2.) U.S. patent application Ser. No. 12/196,407, filed on Aug. 22, 2008, now U.S. Pat. No. 8,137,382 issued on Mar. 20, 2012; and (3.) U.S. patent application Ser. No. 12/196,410, filed on Aug. 22, 2008, now U.S. Pat. No. 8,118,836 issued on Feb. 21, 2012.
The disclosures of the above applications are incorporated herein by reference.
FIELD
The present disclosure relates to method of coupling soft tissue and, more particularly, to a method of coupling soft tissue to a bone.
BACKGROUND
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
It is commonplace in arthroscopic procedures to employ sutures and anchors to secure soft tissues to bone. Despite their widespread use, several improvements in the use of sutures and suture anchors may be made. For example, the procedure of tying knots may be very time consuming, thereby increasing the cost of the procedure and limiting the capacity of the surgeon. Furthermore, the strength of the repair may be limited by the strength of the knot. This latter drawback may be of particular significance if the knot is tied improperly as the strength of the knot in such situations may be significantly lower than the tensile strength of the suture material.
To improve on these uses, sutures having a single preformed loop have been provided. FIG. 1 represents a prior art suture construction. As shown, one end of the suture is passed through a passage defined in the suture itself. The application of tension to the ends of the suture pulls a portion of the suture through the passage, causing a loop formed in the suture to close. Relaxation of the system, however may allow a portion of the suture to translate back through the passage, thus relieving the desired tension.
It is an object of the present teachings to provide an alternative device for anchoring sutures to bone and soft tissue. The device, which is relatively simple in design and structure, is highly effective for its intended purpose.
SUMMARY
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
The present teachings provide for a method for coupling soft tissue to bone. The method includes the following: forming a first bore in a bone; forming a second bore in the bone; positioning a first anchor in the first bore, the first anchor having a first self-locking adjustable suture construct extending therefrom, the first construct including a first adjustable loop, a second adjustable loop, and a pair of first ends; positioning a second anchor in the second bore, the second anchor having a second self-locking adjustable suture construct extending therefrom, the second construct including a third adjustable loop, and a second end; positioning the first adjustable loop relative to the soft tissue; positioning the second adjustable loop about the third adjustable loop; and tensioning the pair of first ends and the second end to pull the first adjustable loop against the soft tissue, couple the second adjustable loop to the third adjustable loop, pull the second adjustable loop against the soft tissue, and pull the third adjustable loop against the soft tissue to thereby couple the soft tissue to the bone.
The present teachings also provide for a method for coupling soft tissue to bone that includes the following: inserting a first anchor in a first bone bore, the first anchor having a first self-locking adjustable suture construct extending therefrom, the first construct including a first adjustable loop, a second adjustable loop, and a pair of first ends; inserting a second anchor in a second bone bore, the second anchor having a second self-locking adjustable suture construct extending therefrom, the second construct including a third adjustable loop, and a second end; positioning the first adjustable loop relative to the soft tissue; compressing a first coupling element connected to the first adjustable loop against the soft tissue by tensioning the pair of first ends; and connecting the second adjustable loop to the third adjustable loop with a second coupling element and compressing both the second adjustable loop and the first adjustable loop against the soft tissue by tensioning the pair of first ends and the second end.
The present teachings further provide for a method for coupling soft tissue to bone including: positioning a first anchor in a first bone bore, the first anchor having a first self-locking adjustable suture construct extending therefrom, the first construct including a first adjustable loop, a second adjustable loop, and a pair of first ends; positioning a second anchor in a second bone bore, the second anchor having a second self-locking adjustable suture construct extending therefrom, the second construct including at least a third adjustable loop, and at least one second end; positioning the first adjustable loop about a first portion of the soft tissue; collapsing a first coupling element connected to the first adjustable loop against the soft tissue by tensioning the pair of first ends; collapsing a second coupling element connected to the third adjustable loop against the second adjustable loop to couple the second adjustable loop to the third adjustable loop by tensioning the second end; and compressing the second adjustable loop and the third adjustable loop against the soft tissue by tensioning both the pair of first ends and the second end.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
FIG. 1 represents a prior art suture configuration;
FIGS. 2A and 2B represent suture constructions according to the teachings;
FIG. 3 represents the formation of the suture configuration shown in FIG. 2A ;
FIGS. 4A and 4B represent alternate suture configurations;
FIGS. 5-7 represent further alternate suture configurations;
FIG. 8 represents the suture construction according to FIG. 5 coupled to a bone engaging fastener;
FIGS. 9-11B represent the coupling of the suture construction according to FIG. 5 to a bone screw;
FIGS. 12A-12E represent the coupling of a soft tissue to an ACL replacement in a femoral/humeral reconstruction;
FIGS. 13A-13D represent a close-up view of the suture shown in FIGS. 1-11B ;
FIGS. 14A and 14B represent the coupling of the suture construction of FIG. 2A and FIG. 4 to bone;
FIGS. 15A-15G represent the coupling of soft tissue to a bone according to the present teachings;
FIGS. 16A-16D represent the coupling of soft tissue to a bone using alternate teachings;
FIGS. 17A-17E represent the coupling of soft tissue to a bone using alternate teachings;
FIGS. 18A-18C represent the coupling of soft tissue to a bone using multiple collapsible loop structures;
FIGS. 19A-19C represent the coupling of soft tissue to a bone using yet alternate teachings;
FIGS. 20A and 20B represent a meniscal repair according to the present teachings;
FIG. 21 represents an insertion tool with associated fastener and soft tissue anchor;
FIG. 22 represents an insertion sleeve associated with the tool shown in FIG. 21 ;
FIGS. 23-31 represent the repair of a rotator cuff using a tool shown in FIG. 21 ;
FIGS. 32-38 represent alternate methods for tying a suture anchor to the fastener;
FIG. 39 represents the suture anchor coupled to a two-piece fastener; and
FIGS. 40-44 represent an alternate system and method of coupling soft tissue to the bone.
DETAILED DESCRIPTION
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
FIG. 2A represents a suture construction 20 according to the present teachings. Shown is a suture 22 having a first end 24 and a second end 26 . The suture 22 is formed of a braided body 28 that defines a longitudinally formed hollow passage 30 therein. First and second apertures 32 and 34 are defined in the braided body 28 at first and second locations of the longitudinally formed passage 30 .
Briefly referring to FIG. 3 , a first end 24 of the suture 22 is passed through the first aperture 32 and through longitudinal passage 30 formed by a passage portion and out the second aperture 34 . The second end 26 is passed through the second aperture 34 , through the passage 30 and out the first aperture 32 . This forms two loops 46 and 46 ′. As seen in FIG. 2B , the relationship of the first and second apertures 32 and 34 with respect to the first and second ends 24 and 26 can be modified so as to allow a bow-tie suture construction 36 . As described below, the longitudinal and parallel placement of first and second suture portions 38 and 40 of the suture 22 within the longitudinal passage 30 resists the reverse relative movement of the first and second portions 38 and 40 of the suture once it is tightened.
The first and second apertures are formed during the braiding process as loose portions between pairs of fibers defining the suture. As further described below, the first and second ends 24 and 26 can be passed through the longitudinal passage 30 multiple times. It is envisioned that either a single or multiple apertures can be formed at the ends of the longitudinally formed passage.
As best seen in FIGS. 4A and 4B , a portion of the braided body 28 of the suture defining the longitudinal passage 30 can be braided so as to have a diameter larger than the diameter of the first and second ends 24 and 26 . Additionally shown are first through fourth apertures 32 , 34 , 42 , and 44 . These apertures can be formed in the braiding process or can be formed during the construction process. In this regard, the apertures 32 , 34 , 42 , and 44 are defined between adjacent fibers in the braided body 28 . As shown in FIG. 4B , and described below, it is envisioned the sutures can be passed through other biomedically compatible structures.
FIGS. 5-7 represent alternate constructions wherein a plurality of loops 46 a - d are formed by passing the first and second ends 24 and 26 through the longitudinal passage 30 multiple times. The first and second ends 24 and 26 can be passed through multiple or single apertures defined at the ends of the longitudinal passage 30 . The tensioning of the ends 24 and 26 cause relative translation of the sides of the suture with respect to each other.
Upon applying tension to the first and second ends 24 and 26 of the suture 22 , the size of the loops 46 a - d is reduced to a desired size or load.
At this point, additional tension causes the body of the suture defining the longitudinal passage 30 to constrict about the parallel portions of the suture within the longitudinal passage 30 . This constriction reduces the diameter of the longitudinal passage 30 , thus forming a mechanical interface between the exterior surfaces of the first and second parallel portions as well as the interior surface of the longitudinal passage 30 .
As seen in FIGS. 8-11 , the suture construction can be coupled to various biocompatible hardware. In this regard, the suture construction 20 can be coupled to an aperture 52 of the bone engaging fastener 54 . Additionally, it is envisioned that soft tissue or bone engaging members 56 can be fastened to one or two loops 46 . After fixing the bone engaging fastener 54 , the members 56 can be used to repair, for instance, a meniscal tear. The first and second ends 24 , 26 are then pulled, setting the tension on the loops 46 , thus pulling the meniscus into place. Additionally, upon application of tension, the longitudinal passage 30 is constricted, thus preventing the relaxation of the tension caused by relative movement of the first and second parallel portions 38 , 40 , within the longitudinal passage 30 .
As seen in FIGS. 9-11B , the loops 46 can be used to fasten the suture construction 20 to multiple types of prosthetic devices. As described further below, the suture 22 can further be used to repair and couple soft tissues in an anatomically desired position. Further, retraction of the first and second ends allows a physician to adjust the tension on the loops between the prosthetic devices.
FIG. 11 b represents the coupling of the suture construction according to FIG. 2B with a bone fastening member. Coupled to a pair of loops 46 and 46 ′ are tissue fastening members 56 . The application of tension to either the first or second end 24 or 26 will tighten the loops 46 or 46 ′ separately.
FIGS. 12A-12E represent potential uses of the suture constructions 20 in FIGS. 2A-7 in an ACL repair. As can be seen in FIG. 12A , the longitudinal passage portion 30 of suture construction 20 can be first coupled to a fixation member or fastener 60 . The fixation member 60 can have a first profile which allows insertion of the fixation member 60 through the tunnel and a second profile which allows engagement with a positive locking surface upon rotation. The longitudinal passage portion 30 of the suture construction 20 , fixation member 60 , loops 46 and ends 24 , 26 can then be passed through a femoral and tibial tunnel 62 . The fixation member 60 is positioned or coupled to the femur. At this point, a natural or artificial ACL 64 can be passed through a loop or loops 46 formed in the suture construction 20 . Tensioning of the first and second ends 24 and 26 applies tension to the loops 46 , thus pulling the ACL 64 into the tunnel. In this regard, the first and second ends are pulled through the femoral and tibial tunnel, thus constricting the loops 46 about the ACL 64 (see FIG. 12B ).
As shown, the suture construction 20 allows for the application of force along an axis 61 defining the femoral tunnel. Specifically, the orientation of the suture construction 20 and, more specifically, the orientation of the longitudinal passage portion 30 , the loops 46 , and ends 24 , 26 allow for tension to be applied to the construction 20 without applying non-seating forces to the fixation member 60 . As an example, should the loops 24 , 26 be positioned at the fixation member 60 , application of forces to the ends 24 , 26 may reduce the seating force applied by the fixation member 60 onto the bone.
As best seen in FIG. 12C , the body portion 28 and parallel portions 38 , 40 of the suture construction 20 remain disposed within to the fixation member 60 . Further tension of the first ends draws the ACL 64 up through the tibial component into the femoral component. In this way, suture ends can be used to apply appropriate tension onto the ACL 64 component. The ACL 64 would be fixed to the tibial component using a plug or screw as is known.
After feeding the ACL 64 through the loops 46 , tensioning of the ends allows engagement of the ACL with bearing surfaces defined on the loops. The tensioning pulls the ACL 64 through a femoral and tibial tunnel. The ACL 64 could be further coupled to the femur using a transverse pin or plug. As shown in FIG. 12E , once the ACL is fastened to the tibia, further tensioning can be applied to the first and second ends 24 , 26 placing a desired predetermined load on the ACL. This tension can be measured using a force gauge. This load is maintained by the suture configuration. It is equally envisioned that the fixation member 60 can be placed on the tibial component 66 and the ACL pulled into the tunnel through the femur. Further, it is envisioned that bone cement or biological materials may be inserted into the tunnel 62 .
FIGS. 13A-13D represent a close-up of a portion of the suture 20 . As can be seen, the portion of the suture defining the longitudinal passage 30 has a diameter d 1 which is larger than the diameter d 2 of the ends 24 and 26 . The first aperture 32 is formed between a pair of fiber members. As can be seen, the apertures 32 , 34 can be formed between two adjacent fiber pairs 68 , 70 . Further, various shapes can be braided onto a surface of the longitudinal passage 30 .
The sutures are typically braided of from 8 to 16 fibers. These fibers are made of nylon or other biocompatible material. It is envisioned that the suture 22 can be formed of multiple type of biocompatible fibers having multiple coefficients of friction or size. Further, the braiding can be accomplished so that different portions of the exterior surface of the suture can have different coefficients of friction or mechanical properties. The placement of a carrier fiber having a particular surface property can be modified along the length of the suture so as to place it at varying locations within the braided constructions.
FIGS. 14A and 14B represent the coupling of suture construction 22 of FIG. 2A and FIG. 4 to a bone. The longitudinal passage 30 is coupled to a fixation member 60 which can be disposed within an aperture formed in the bone. The fixation member 60 can be, for example, a staple or a bone engaging screw. After coupling the suture construction 22 to the bone, loops 46 and 47 and ends 24 and 26 are readily accessible by the physician. The application of tension to the ends 24 and/or 26 causes the loops 46 and 47 to constrict. The loops 46 and 47 can be used to couple two or more portions of the anatomy. In this regard, the loops can be used to couple bone to bone or soft tissue to bone.
FIGS. 15A-15G represent the coupling of soft tissue 80 to bone. As shown in FIGS. 15A and 15B , the suture construction 22 is disposed about a portion of the soft tissue 80 . Alternatively, an aperture or hole 84 can be formed in the soft tissue 80 . A portion of the suture construction 22 , for example, a loop 46 or loops 46 , 47 or ends 24 and 26 can be threaded or pulled through the aperture 84 . As seen in FIG. 15B , a single loop 46 of suture can be coupled to the fastener 60 . This single loop 46 can be disposed over or around the soft tissue 80 .
As shown in FIG. 15C , one loop 46 can have a fastening element 70 coupled thereto. This fastener element 70 can take the form of a loop of suture having a knot 72 . This fastening element 70 along with the loop 46 and one or more strands 24 can be passed through the aperture 84 formed in the soft tissue 80 .
FIG. 15D shows the second loop 47 can be passed around the soft tissue and coupled to the fastening element 70 . The first and second loops 46 and 47 are coupled together about the soft tissue 80 , and optionally can be positioned about the knot 72 .
As shown in FIG. 15E , the first loop 46 and first end 24 can be passed through an aperture 84 of the soft tissue 80 . Coupled to the first loop 46 is a fastener 70 in the form of a suture having a knot 72 . The second loop 47 can be passed through the suture 70 and the knot 72 so as to form a pair of locking loops 73 (see FIG. 15F ). FIG. 15G shows that tension can be applied to the first and second ends 24 and 26 of the suture 22 to constrict the suture 22 about the soft tissue 80 . In this regard, the first and second loops 46 and 47 are tightened to constrict about and fix the soft tissue 80 to the bone.
As seen in FIG. 16A , the construction of FIGS. 14A and 14B can be modified so as to place a pair of collapsible fabric tubes 74 and 76 about a portion of the suture 22 . In this regard, collapsible tubes 74 and 76 can be coupled to the first and second suture loops 46 and 47 . It is also envisioned several collapsible tubes can be coupled to a single loop 46 or the suture ends 26 , 27 .
The collapsible tubes 74 and 76 can be either threaded onto ( 76 ) or disposed about a loop 75 formed in the suture loop 46 . As seen in FIG. 16B , the first collapsible tube 76 can be fed through the loop 75 . When tension is applied to the second end 26 of the sutures 47 , the first loop 46 constricts about the second loop causing the collapse of the first collapsible tube 74 . As shown in FIG. 16D , tension can be applied to the first suture end 24 causing the second loop 47 to constrict causing the collapse of the second collapsible tube 76 and the subsequent locking of the soft tissue 80 to the bone.
FIGS. 17A-17E represent an alternate method for coupling soft tissue 80 to a bone using the construction of FIGS. 14A and 14B . As shown in FIG. 17A , the first loop 46 and first suture end 24 are passed through an aperture 84 formed in the soft tissue 80 . The second loop 47 is passed through the first loop 46 .
The second loop 47 is then doubled back over the first loop 46 causing a pair of intermediate loops 77 . As shown in FIG. 17D , a locking member 70 , soft or hard, can then be passed through the pair of intermediate loops 77 or a portion of the first loop 75 to lock the first and second loops 46 and 47 together. As shown in FIG. 17E , tension applied to the suture ends 26 , 27 tighten the loops 46 and 47 about the locking member 70 . The soft tissue 80 is also fixed to the bone.
FIGS. 18A-18C represent alternate suture constructions 22 which are used to couple soft tissue 80 and 81 to bone. Disposed about the first and second loops 46 and 47 are collapsible tubes 74 and 76 . The tubes 74 and 76 which can be, for example, fabric or polymer, can either be directly disposed about the suture 22 of the first and second loops 46 and 47 , or can be coupled to the suture loops 46 and 47 using a separate loop member 81 .
As shown in FIG. 18C , the suture construction 22 shown in FIGS. 18A or 18B , the collapsible tubes 74 and 76 are passed through the apertures 84 formed in the soft tissue 80 . The application of tension to the ends 26 and 27 causes the soft tissue 80 to be drawn against the bone and cause compressive forces to be applied to the collapsible tubes 74 and 76 . By tightening the suture which passes through the passage 30 , the soft tissue 80 is coupled to the bone without the use of knots.
As can be seen in FIGS. 19A-19C , several fixation members 60 and 60 ′ can be coupled to the suture construction 22 to fasten soft tissue 80 to bone. As seen in FIG. 19A , the collapsible tube 74 can be coupled to a first loop 46 while the second loop 47 can be used to couple the first suture 22 to the second fastener 60 ′. In this regard, they are coupled using a collapsible tube 76 of the second suture 22 ′, thus allowing downward force along the entire length between the fasteners, thus providing bridge fixation as well as point fixation.
As seen in FIG. 19B , tension of the ends 24 and 26 of the first suture 22 draws the second loop 47 into the fixation member 60 ′. The second loop 47 of the first suture 22 is then coupled to the collapsed tube 76 . This couples the first and second fasteners together and applies the downward force.
As seen in FIG. 19C , the second loop 47 of the first suture 22 can be passed through a second aperture 86 in the soft tissue 80 . A second loop 47 is then coupled to the collapsible tube 76 associated with the second suture 22 ′. The collapsed tube 76 of the second suture 22 ′ functions to fix the suture 22 ′ to the fixation member 60 ′. It is envisioned the collapsed tube 76 can be found within a bore defined in the bone or the fastener 60 .
FIGS. 20A and 20B represent the use of a suture construction 22 to repair a meniscus. Fasteners 82 are coupled to first and second loops 46 and 47 . After the fixation member 60 is coupled to bone or soft tissue, the first loop 46 is passed through a first aperture 84 in a first portion of the meniscus. The first loop and collapsible tube 74 is then passed through a second aperture 86 and a second portion of the meniscus. The second loop 47 and second collapsible tube 76 are similarly passed through the meniscus. Tension is applied to the first and second ends 24 and 26 of the suture 22 to pull the meniscus together. As seen in FIG. 20B , a first and second collapsible tube 74 and 76 are constricted so as to couple the suture to the meniscus.
FIG. 21 represents a tool 100 with associated fastener 102 and soft tissue anchor 104 . The tool 100 has a handle portion 106 which releasably engages the fastener 102 . Associated with the handle portion 106 is a hollow longitudinal suture 103 which accepts a soft tissue anchor 104 . Disposed at a distal end 110 of the hollow longitudinal portion 108 is a slot having a portion of the soft tissue anchor 104 disposed therethrough. The distal end 110 is further configured to support the fastener 102 for insertion into a bore defined within bone 112 .
FIG. 22 represents an insertion guide 115 having a handle portion 114 and a curved longitudinal guide tube 116 . The longitudinal guide tube 116 and handle portion 114 slidably accept the fastener 102 and soft tissue anchor 104 . The curved longitudinal tube 116 and handle portion 112 define a slot 118 which also slidably accepts the suture 103 of soft tissue anchor 104 .
FIGS. 23-38 generally depict the repair of labral tissue of a glenoid. While the repair shown generally relates to a specific anatomical injury, it is envisioned the teachings herein can be applied to other anatomical regions which require the coupling of soft tissue to bone. For example, a meniscal repair in a knee may be performed using similar techniques. As shown in FIG. 23 , access to the region of the injury is made through a tube 120 . At this point, a collapsible tube 122 having an extended portion 124 is threaded through tube 120 into close proximity of the soft tissue 126 to be coupled to bone. A suture grabber 128 such as a speed pass by Biomet Sports Medicine is used to pierce the soft tissue 126 and to grab the extended portion 124 of the collapsible tube 122 . This extended portion 124 is then pulled through the soft tissue 126 .
As shown in FIG. 24 , the extended portion 124 of the collapsible tube 122 is fed back out the access tube 120 and clamped with clamp 129 so as to prevent inadvertent translation with respect to the tube. As shown in FIG. 25 , the insertion sleeve 115 is placed through the access tube 120 . The collapsible tube 122 is placed through the slot 118 defined in the handle portion 114 and longitudinal guide tube 116 .
FIG. 26 shows a drill 130 having a flexible drive shaft 132 and a bone cutting drill bit 134 . The drill bit 134 is placed through the guide tube 116 to form a bore 136 in bone at a location adjacent to a soft tissue repair. It is envisioned the bore 136 can be placed under or adjacent the soft tissue repair.
After the bore 136 has been formed in the bone, the tool 100 , fastener 102 , and associated soft tissue anchor 104 are placed through the insertion guide 115 . As shown in FIG. 28 , the fastener is inserted into the bore 136 . It is envisioned the fastener 102 can be a two-part fastener having a first insertion portion 140 and a locking portion 142 . The locking portion 142 can have a plurality of expandable bone engaging members 144 .
As seen in FIG. 30 , the pair of sutures 146 can be pulled through the soft tissue 126 . The sutures 146 can be coupled together using a suture construction shown in FIGS. 1A or 1B . In this regard, the suture 146 can be looped through an integrally formed collapsible member or tube 148 which can be used to fix the suture construction with respect to either the insert or locking portion 140 , 142 of the fastener.
As shown in FIG. 31 , when tension is applied to the suture 146 through the tool 100 , a collapsible portion 150 of the collapsible tube engages the soft tissue 126 . As seen in FIGS. 32-33B , once the collapsible portion 150 of the collapsible tube is set, the tool 100 can be removed from the insertion guide 115 . At this point, the end of the longitudinal tube can be removed, or can be tied to the suture 146 .
FIGS. 34-36 represent an alternate method for coupling a suture construction 104 to the fastener 102 . Shown is a fastener 102 being passed through the loop of the suture. In this regard, the fastener 102 is passed through the loop of the suture prior to insertion of the fastener 102 within the bore 136 in the bone. After removal of the tool 100 , tension is applied to the ends of the suture to constrict the collapsible portion 150 of the collapsible tube. This tensioning pulls the soft tissue 146 into a position with respect to the fastener 102 .
As shown in FIGS. 37 and 38 , the fastener 102 can have an associated integral loop 120 . The integral loop 120 can be a suture or can be an integral polymer construction. The compressible tube 122 can be threaded through the integral loop 120 . Application of tension onto the suture causes the collapsible portion 150 of the collapsible tube to bear against the integral loop 120 and the soft tissue. It is envisioned the integral loop can be elastically deformable or can be fixed with respect to the fastener.
FIG. 39 represents a suture construction coupled to a two-piece fastener 102 . The suture construction 104 can be threaded through the aperture formed within the first or second portions of the fastener 102 . As shown, an integrally formed collapsible tube portion 148 can be disclosed within the aperture of the fastener. Upon application of tension onto the suture, the tension will cause the collapse of this second collapsible tube portion 148 , thus locking the suture to the fastener body 102 .
FIGS. 40-44 represent an alternative system and method of coupling soft tissue to bone. By way of non-limiting example, a fastener 102 can be coupled to the bone as described above and shown in FIGS. 23-30 . Subsequent to this, the collapsible portion 150 of the tube 104 can be passed through the soft tissue 126 .
As best seen in FIGS. 40-42 , a drive tool 160 is used to form a soft tissue engagement site 162 in a bone structure. The tool 160 has a drive (not shown) which rotates a bone cutting bit 164 . The bone cutting bit 164 has a first portion 166 configured to drill a hole 167 through cortical bone and a threaded second portion 168 . The threaded second portion 168 is configured to cut threads in the cortical 169 and cancellous bone 171 structures. This is accomplished by advancing the cutting bit 164 into the bone at a predetermined rate while rotating the bit at a predetermined speed. As shown in FIG. 41 , after the second portion 168 has entered the cancellous bone 171 , the bit is rotated while keeping the rotating tool 160 in a substantially stationary position. The thread cutting threads of the second portion 168 then displace cancellous bone 171 , forming the cavity 162 . The bit is removed by rotating the thread cutting threads through the threads formed in the cortical bone 169 .
As shown in FIG. 43 , the collapsible tube 104 of suture anchor is passed through passage 167 and into the cavity 162 . In this regard, an insertion tool 173 can be used to insert the collapsible tube 104 into the cavity 162 . As shown in FIG. 44 , tension is applied to the end 172 of the suture anchor, thus causing the collapsible portion 104 of the anchor.
The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. For example, any of the above mentioned surgical procedures is applicable to repair of other body portions. For example, the procedures can be equally applied to the repair of wrists, elbows, ankles, and meniscal repair. The suture loops can be passed through bores formed in soft or hard tissue. It is equally envisioned that the loops can be passed through or formed around an aperture or apertures formed in prosthetic devices e.g. humeral, femoral or tibial stems. Further, the suture material and collapsible tubes can be formed of resorbable material. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
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A method for coupling soft tissue to bone including: positioning a first anchor in a first bone bore, the first anchor having a first self-locking adjustable suture construct including a first adjustable loop, a second adjustable loop, and a pair of first ends; positioning a second anchor in a second bone bore, the second anchor having a second self-locking adjustable suture construct including a third adjustable loop, a fourth adjustable loop, and a second end; positioning the first adjustable loop relative to the soft tissue; positioning the second adjustable loop about the third adjustable loop; and tensioning the pair of first ends and the second end to pull the first adjustable loop against the soft tissue, couple the second adjustable loop to the third adjustable loop, pull the second adjustable loop against the soft tissue, and pull the third adjustable loop against the soft tissue.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a transfer case for an all-wheel drive (AWD)/four-wheel drive (4WD) vehicle and, more particularly, to a transfer case for an AWD/4WD vehicle that employs a rear output shaft bushing that is cast with the transfer case housing, where the bushing incorporates a spiral groove for allowing lubricant flow therethrough.
2. Discussion of the Related Art
Various sport utility vehicles (SUV), off-road vehicles, four-wheel drive vehicles, etc. are equipped with drive modes that allow the vehicle to be driven in one or more of two-wheel drive high, four-wheel drive high, four-wheel drive low and AWD. Typically, these types of vehicles employ transfer cases that distribute the drive power received from an output shaft of the vehicle's transmission. Particularly, the output shaft of the transmission is coupled to an input shaft of the transfer case that distributes drive power to a front output shaft that is coupled to a front drive shaft that drives the vehicle's front wheels and a rear output shaft that is coupled to a rear drive shaft that drives the vehicle's rear wheels. Known transfer cases have employed various types of couplings, such as viscous couplings, electromagnetic clutches, positionable spur gears, etc., that allow the drive power from the transmission to be distributed to the front and rear drive shafts to provide the various drive modes.
The rear output shaft of the transfer case is coupled to the rear drive shaft by a slip yoke. The rear drive shaft is coupled to a rear axle of the vehicle, which is mounted to a vehicle suspension system. As the vehicle travels, the rear axle moves up and down in response to road conditions. As the rear axle moves up and down, the slip yoke slides on the rear output shaft so that the suspension load is not significantly transferred thereto. A bushing is typically employed in the opening of the transfer case housing through which the rear output shaft extends. The slip yoke is supported and rotates within the bushing, and is able to reciprocate therein along the axis of the output shaft. This allows the rear drive shaft to slide relative to the rear output shaft in response to rough driving conditions.
The housing of the transfer case is typically cast in two or more pieces and then bolted together. For example, a portion of the transfer case housing is sometimes cast as a separate cover housing and extension housing. An opening through which the rear output shaft extends is then machined into the appropriate housing piece to accept the bushing. The bushing is then pressed into the housing piece in a friction engagement before the housing pieces are bolted together. An inner surface of the bushing is then machined so that it has an internal diameter suitable for the outer diameter of the slip yoke.
It is desirable to limit the number of housing pieces to reduce costs and assembly time. However, if the housing piece to which the bushing is mounted is too large, then it becomes too difficult to machine the opening in the transfer case that accepts the bushing. Further, the bushing has a tendency to spin out of the opening in response to the load applied thereto from the slip yoke during operation. Also, the load from the slip yoke significantly increases the temperature of the bushing, that may lead to part failure of the bushing and/or rear output shaft.
SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention, a transfer case for an AWD/4WD vehicle is disclosed that employs a bushing positioned within a housing of the transfer case. A slip yoke is inserted into the bushing and is rotatable therein. A rear drive shaft is rigidly coupled to the yoke. An output shaft of the transfer case is rigidly coupled to the yoke so that they rotate together and the yoke can slide in an axial direction relative to the output shaft. The bushing is formed to the housing when the housing is cast. The bushing includes one or more axial notches formed in an outer surface of the bushing that fill with housing metal during the casting process that prevent the bushing from rotating in response to the load from the slip yoke. A helical or spiral groove is formed in an inner surface of the bushing and a slot is formed through a housing wall along the bushing that allows lubricant from within the housing to flow through the groove.
Additional advantages and features of the present invention will become apparent to those skilled in the art from the following discussion and the accompanying drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the drive components of an AWD/4WD vehicle employing a transfer case, according to an embodiment of the present invention;
FIG. 2 is a cross-sectional view of part of the transfer case of the invention shown in FIG. 1 ;
FIG. 3 is another cross-section view of part of the transfer case of the invention shown in FIG. 1 ; and
FIG. 4 is a rear-view of the transfer case showing a bushing employed therein.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The following discussion of the embodiments of the invention directed to a transfer case for an AWD/4WD vehicle that includes a rear output shaft bushing is merely exemplary in nature, and is in no way intended to limit the invention or it's applications or uses.
FIG. 1 is a plan view of the drive components of an AWD/4WD vehicle 10 . The vehicle 10 includes an internal combustion engine 12 that provides the power to drive the vehicle 10 , as is well understood in the art. A drive shaft (not shown) is rotated by the engine 12 , and is coupled to a transmission 14 that converts the output power from the engine 12 to a selectively geared output. The operation of the engine 12 and the transmission 14 are well understood to those skilled in the art, and need not be discussed in detail here for a proper understanding of the invention.
The output drive power from the transmission 14 is provided to an input shaft 18 of a transfer case 16 . The transfer case 16 selectively provides output drive power to a pair of rear wheels 20 and 22 and a pair of front wheels 24 and 26 . In the two-wheel drive mode, drive power is only provided to the rear wheels 20 and 22 . The transfer case 16 can also be shifted to neutral, where the transmission 12 is disengaged from the transfer case 16 and the wheels 20 - 26 can rotate freely for towing and the like.
The transfer case 16 includes a rear output shaft 30 and a front output shaft 32 . The rear output shaft 30 is coupled to a rear drive shaft 34 by a slip yoke 28 , and the rear drive shaft 34 is coupled to a rear differential 36 . A first rear axle 38 is coupled at one end to the differential 36 and at an opposite end to the wheel 20 . Likewise, a second rear axle 40 is coupled at one end to the differential 36 and at an opposite end to the wheel 22 . The transfer case 16 provides output power on the rear output shaft 30 , which provides rotational energy to the rear drive shaft 34 . This rotational energy is transferred through the rear differential 36 and the axles 38 and 40 to the wheels 20 and 22 in a manner that is well understood in the art. The rear axles 38 and 40 are coupled to a vehicle suspension system (not shown) so that the axles 38 and 40 move up and down in response to the road conditions. The slip yoke 28 allows the rear drive shaft 34 to slide independent of the rear output shaft 30 so that this load is not significantly imparted to the transfer case 16 .
The front output shaft 32 is coupled to a front drive shaft 44 by a slip yoke 42 , and the drive shaft 44 is coupled to a front differential 46 . A first front axle 48 is coupled at one end to the front differential 46 and at an opposite end to the wheel 24 . Likewise, a second front axle 50 is coupled at one end to the front differential 46 and at an opposite end to the wheel 26 . Drive energy on the front output shaft 32 drives the front drive shaft 44 , and the front differential 46 transfers the drive energy to the wheels 24 and 26 through the front axles 48 and 50 .
A switch 54 , generally mounted on the dashboard of the vehicle 10 , allows the vehicle operator to select the drive mode for two-wheel drive (2WD), AWD or neutral (N). The switch 54 provides a signal to a controller 56 indicating the drive mode selection. The controller 56 provides a control signal to the transfer case 16 to cause the transfer case 16 to make the shift to the desired drive mode, as will be discussed in detail below.
FIGS. 2 and 3 are cross-sectional views of a housing portion 60 of the transfer case 16 . The housing portion 60 is a cast metal member that would be bolted to another housing portion (not shown) to form the complete transfer case housing, as would be understood by those skilled in the art. The housing portions would include various seals, recesses, shoulders, flanges, bores, etc. that accept and position the various components and parts of the transfer case 16 . The rear output shaft 30 is rotatably coupled to the input shaft 18 within the transfer case 16 by various gears, bearings, etc. (not shown) in any suitable manner that would be well understood to those skilled in the art. For example, the input shaft 18 may be coupled to the rear output shaft 30 by a planetary gear assembly (not shown) to provide the desired gear ratio between the input and output of the transfer case 16 . Further, the rear output shaft 30 would be selectively coupled to the front output shaft 32 by a sprocket and chain assembly (not shown) to provide the drive power to the front output shaft 32 for the AWD/4WD drive mode. The coupling between the input shaft 18 and the rear output shaft 30 is not shown in any detail because any type of coupling system suitable for a transfer case can be employed.
As discussed above, the rear drive shaft 34 is mounted to the rear output shaft 30 by the slip yoke 28 . The rear drive shaft 34 is rigidly mounted to the slip yoke 28 , and the slip yoke 28 is rotatably and slidably mounted to the rear output shaft 30 . Particularly, the rear output shaft 30 includes axial splines 62 on its outer surface and the yoke 28 includes cooperating splines 64 on its inner surface that allow the yoke 28 to slide axially relative to the output shaft 30 . A seal 66 is mounted to an annular extension 74 , as shown, to seal the housing portion 60 of the transfer case 16 .
According to the invention, the transfer case 16 includes a bushing 70 mounted to an annular shoulder portion 68 of the housing portion 60 , as shown. FIG. 3 does not show the yoke 28 and the rear output shaft 30 for clarity purposes to better show the bushing 70 . FIG. 4 is a rear-view of the housing portion 60 showing the bushing 70 . As is well understood in the art, the slip yoke 28 rotates on an inner surface 72 of the bushing 70 , and reciprocates in an axial direction within the bushing 70 in response to a rebound rear axle suspension system to provide a slip engagement with the rear output shaft 30 . This allows the rear drive shaft 34 to move independent of the transfer case 16 .
According to the invention, the bushing 70 is mounted to the shoulder portion 68 when the housing portion 60 is cast. Particularly, the bushing 70 is placed in the die cast, and the molten metal forming the housing portion 60 flows around it. In one embodiment, the bushing 70 is a sintered bronze bushing. However, this is by way of a non-limiting example, in that the bushing 70 can be made of any material suitable for the purposes described herein. By casting the bushing 70 with the housing portion 60 , the opening in which the bushing 70 would normally be pressed into does not need to be machined, and the bushing 70 does not need to be later press fit into the housing portion 60 , as was previously done in the art.
If the slip yoke 28 is cocked or angled relative to the axis of the bushing 70 in response to the up and down movement of the rear wheels 20 and 22 , it can exert a significant load thereon. To prevent the bushing 70 from rotating within the shoulder 68 in response to the load, the bushing 70 includes a series of axial notches 76 formed in an outer surface 78 of the bushing 70 that receive molten metal when the housing portion 60 is cast. In this embodiment, there are twelve notches 76 symmetrically disposed around the outer surface 78 of the bushing 70 . However, this is by way of a non-limiting example, in that any suitable number or size of the notches 76 can be provided within the scope of the present invention. The notches 76 prevent the bushing 70 from rotating within the housing portion 60 under the load from the yoke 28 . Because the bushing 70 cannot spin within the housing portion 60 , it will not push on the seal 66 , causing failure of the transfer case 16 .
Further, the load applied to the bushing 70 from the slip yoke 28 creates a significant heat build-up. According to the invention, a spiral or helical groove 80 is machined into the inner surface 72 of the bushing 70 after it is cast to the housing portion 60 . Further, a slot 82 is machined through the shoulder 68 proximate the outer surface 78 of the bushing 70 . The transfer case 16 is mounted to the vehicle 10 so that the rear portion of the transfer case 16 is slightly lower than the front portion of the transfer 16 . This allows lubricating oil within the transfer case 16 to collect within the housing portion 60 proximate the bushing 70 . The oil will flow through the slot 82 under gravity and into a chamber 84 between the seal 66 and the bushing 70 . The oil will be pumped by the helical groove 80 as the yoke 28 and the output shaft 32 rotate back into the housing portion 60 . Therefore, a constant supply of cooling and lubricating oil is provided to the space between the inner surface 72 of the bushing 70 and the yoke 28 to control the heat build-up. The level of the oil in the housing portion 60 is not high enough to cover the opening of the groove 80 into the housing portion 60 .
The foregoing discussion describes merely exemplary embodiments of the present invention. One skilled in the art would readily recognize that various changes, modifications and variations can be made therein without departing from the spirit and scope of the invention as defined in the following claims.
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A transfer case for AWD/4WD vehicle that employs a bushing positioned within a transfer case housing. The bushing is formed to the housing when the housing is cast. The bushing includes one or more axial notches formed in an outer surface of the bushing that fill with the housing metal during the casting process that prevents the bushing from rotating in response to a load from a slip yoke. A helical groove is formed in the inner surface of the bushing and a slot is formed through a housing wall along the bushing that allows lubricant from within the housing to flow through the bushing.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to a use billing system with an arrangement for identifying distances traveled by a moving object (e.g., a passenger automobile, motorcycle, truck, bus, ship, railroad train, aircraft, person, piece item) within a system of traveled distances (e.g., a highway system, waterway system, railroad system) or for identifying geographical zones (e.g., inner-city zones, air space zones, nature preserve zones) entered by the object.
2. Description of the Prior Art
A position detection system for a motor vehicle is known from EP-A-0 519 630. This system determines position data via the GPS system and shows the data on a display. This GPS system is also used for another position detection system described in EP-A-0 519 630. The data can be recorded on a memory card or a PC.
Finally, DE-A-35 37 730 discloses an arrangement for automatically homing on a target point. For this purpose, position finding is carried out via a transmitter in a known location and the actual course of the moving object is determined therefrom.
Charges for the use of bridges or tunnels are commonly collected at toll stations similar to border posts, where the fee is collected by personnel or automatic coin payment machines. In order to charge for the use of sections of highway in France and Italy, a system is used in which the driver takes a ticket on which the entry point is marked in a machine-readable manner when entering the highway and at the junction between a toll-free highway section and a toll highway section. At the exit or when passing from a toll highway section to a toll-free highway section, the total traveled distance can be determined by means of this ticket and the respective use charge can be calculated and collected. Although this system enables reliable billing, its use requires not only considerable investment to provide the necessary infrastructure, in particular for construction of toll stations with automatic ticket machines, barriers and lighting installations, etc., but also a considerable expense for personnel to man the toll stations during the day and night. An additional grave disadvantage consists in that the toll collecting activities severely impede the flow of traffic especially at peak traffic hours.
In order to avoid this expense, Switzerland has for a number of years employed a different system for collecting tolls for the use of highways which is based on a lump payment for a fixed time period. In exchange for a lump payment, the driver receives a sticker which is to be placed in a visible location in the vehicle and which shows an externally visible authorization to travel on the highway and accordingly presents a verifiable record. This system requires no substantial expenditure on infrastructure, since it can make use of existing installations for selling the stickers (e.g., post offices, border posts) and for monitoring (e.g., highway entries and exits). However, it is not possible to charge for the actual extent of use, so that the calculation of costs does not adequately take into account the principle that payment should be commensurate with use.
Systems which permit an individual charge based on the actual extent of use have also already been suggested. However, these systems require that a suitable local infrastructure be provided, since they are based, for instance, upon infrared systems or so-called h-f transponder systems or r-f transponder systems, that is, upon special mechanical devices for detecting and identifying individual vehicles on the toll routes in question or in corresponding fixed geographical zones such as inner-city zones in which automobile traffic is to be restricted. The transponder technique has been known for some years from its use in the field of military air traffic for distinguishing enemy flying objects from friendly flying objects. The applied principle consists in that an object to be identified is "beamed" (e.g., by radar) from a monitoring station (e.g., a ground station, a ship or an aircraft) and an appropriate identification signal is then sent automatically to the respective monitoring station. In order to transfer this principle to a highway toll charging system, for instance, suitable mechanical monitoring stations would have to be provided at determined points along the highway toll route system (particularly at entry and exit points) to enable a complete acquisition of the data required for use billing. Accordingly, a system of this kind requires a considerable expenditure for providing a special infrastructure covering a surface area.
SUMMARY OF THE INVENTION
The object of the present invention is to an arrangement of the type mentioned above which is suitable not only for charging fees for highway use, but also for detecting other instances of use of defined zones (distances, surface areas, spaces) by moving objects and which requires comparatively little expenditure on infrastructure.
Pursuant to this object, and others which will become apparent hereafter, one aspect of the present invention resides in a use billing system having an arrangement for identifying distances traveled by a moving object within a system of traveled distances or for identifying fixed geographical zones entered by the object. The use billing system includes a transmission system installed outside the moving object independently from the distances and fixed geographical zones to be traveled for wireless transmission of information to detect the current geographical position of the object. A reception system is carried by the moving object and is operative to receive the information from the transmission system for detecting the position which is transmitted over the air. A first storage device as carried by the object for a temporary storage of data concerning the current geographical position of the object. A second storage device is carried by the object for permanent storage of predetermined geographical positions for unequivocal identification of the individual travel distances of the system of traveled distances and/or the fixed geographical zones. A comparison device is carried by the object for preparing the respective geographical position of the object determined at regular intervals with the position data of the identification points. An identification device that is also carried by the object identifies the distance traveled by the object and/or the fixed geographical zone entered or exited by the object on the basis of the geographical positions which have just been passed by the object and which have been determined by the comparison device and agree with the identification points. Finally, the billing system has a mobile storage module which can be connected with the identification device by computer techniques and in which the respective identified distances currently being traveled and/or the presence in a fixed geographical zone is logged.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be described more fully in the following with reference to a system for charging fees for the use of highways by way of example. The drawing in FIG. 1 shows a section of a road system with a highway. FIG. 2 is a block diagram of the system components.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The system according to the invention is formed of three main functional blocks, namely:
a position detection system on board the vehicle;
a billing system on board the vehicle; and
a portable or mobile storage medium for storing billing data.
The position detection system has a system 10 for receiving information for detecting the current geographical position of the vehicle and a first storage device 11 for temporary storage of the current position. The information for position detection is received over the air by a system 12 installed independently from of the highway system. This system is often already present or can be adjusted at relatively low cost for the purpose of transmitting appropriate information. Some examples are existing satellite navigation systems (e.g., GPS, GLONASS) or direction finder systems based on existing mobile telephone communications networks (e.g., the German C-, D-, and E-networks) by which a very accurate position detection can be effected on the basis of different signal propagation times to neighboring ground stations. In satellite navigation systems, it may be advantageous to provide the opportunity to receive correction signals (e.g., for the differential GPS system) in order to increase the accuracy of position detection. This compensates for influences due to errors such as satellite orbit errors, timing errors, and signal propagation errors and enables a location resolution of less than 10 m. A correction signal of this kind could be transmitted, for instance, by radio broadcasting (e.g., RDS) or by a GSM mobile communications network. Other systems which determine the vehicle position from radio contact and from sensor equipment installed in the vehicle are also possible. For example, a sensor for determining mileage (e.g., via the revolutions of the rear wheels) and a fluxgate can be provided which enable accurate position-finding with reference to a digitized system of roads when the position of the vehicle is obtained prior to the start of the trip by means of a communications device installed within the vehicle. A "dead reckoning sensor" 13 (e.g., in the form of a fluxgate) which is carded on board the vehicle can be provided to enable a continuous updating of position data in the event of a temporary malfunction of a position detection system (e.g., due to shielding effects or unfavorable satellite position).
The billing system carried on board the vehicle contains a second storage device 14 for permanent storage of predetermined geographical positions (identification points) allowing for an unambiguous identification of individual traveled distances on the system of routes and/or of fixed zones. Further, there is a computing unit which operates as a comparison device 15 and which constantly compares the current position of the vehicle with the stored position data (coordinates) of the identification points at frequent intervals (e.g., once or twice every second). If the agreement between the position data is sufficiently exact, the computing device identifies the section of highway which has just been traveled over and which can be associated with this identification point. This will be explained in more detail in the following.
The use of identified sections of highway is logged by the computing device on a mobile storage medium 16. By mobile storage medium 16 is meant a device which can be carried by the driver of the vehicle and which, if needed, can be connected with the computing device via a read-write device by computer technique. This mobile storage medium is preferably constructed as a magnetic-tape card or chip storage card. However, other media, e.g., programmable storage components such as PAL components, FPLA components or FPLS components, can also be used.
If the information received externally from the position detection system is not position data in a strict sense, the computing device additionally takes on the task of calculating the coordinates of the respective position of the vehicle from this information. The second storage device with the position data for the identification points can be physically integrated in the first storage device. However, it may also be advantageous to integrate the second storage device in the mobile storage module.
The principle of use billing can be illustrated with reference to the section of a system of distances shown in FIG. 1 which shows a toll highway 1 as well as toll-free roads 4, 5, 6 crossing the highway 1. The entry/exit points 2a and 2b of the highway 1 are identified by squares. The geographical positions of these locations are stored in the second storage device as identification points. When the computing device detects a current vehicle position which is in agreement with the position of square 2a or square 2b (with predetermined accuracy), this can mean that the vehicle is located on a toll section of highway. However, it might also mean that the highway 1 has only been crossed via the toll-free road 4 or 5. Even when a second square is passed, there is still no unequivocal determination in this respect. For example, it is also possible to travel from square 2a to square 2b via roads 4 and 5, that is, just as can be done via the highway 1. For this reason, at least one additional identification point 3a, 3b (marked by a circle) on the highway 1 is provided and stored between every two directly successive entry/exit points on the highway 1. This additional identification point, when passed subsequent to an identified entry point/exit point, enables a completely unequivocal determination to be made regarding the section of highway that has just been traveled over, so that a corresponding record can be made on the mobile storage medium for calculating charges. Highway crossings and highway triangles are also detected as identification points with their position coordinates in order to provide a complete identification of all portions of the network of highway sections.
In principle, it would also be possible to effectively bill for use by the month, for instance, by referring to the recorded instances of use at fee payment locations. However, it is considerably more advantageous to use the mobile storage medium like a telephone card; that is, the user purchases a "highway toll card" thus already acquiring beforehand the authorization to make use of the highway to a determined extent (use credit). When the highway is actually used, the charge for every traveled distance is deducted from the actual use credit by recording means 22.
A great advantage is obtained by storing use rates on the mobile storage medium in addition to the identification points of the highway system in that graduated authorizations for use can be realized in a simple manner. For example, it is possible to issue special highway toll cards for the use of determined regions or routes (e.g., transit highways). Different sets of charges to be applied for different vehicle types (passenger automobiles, motorcycles, busses, trucks) can also easily be taken into account by means of highway toll cards with a suitable different design and which are provided with different rates.
The components of the device according to the invention which are internal to the vehicle and which are preferably designed as compact mobile logging devices 21 can also be physically integrated, for instance, within a car radio, a terminal of a traffic control system 20 or in a mobile telephone set and can accordingly be permanently installed in the vehicle. Mobile devices are particularly handy for calculating charges for foreign vehicles which are not outfitted with corresponding arrangements. Thus, in addition to highway use cards, logging devices 21 could also be issued at border crossings for an appropriate fee. The logging device is preferably activated by inserting the highway use card into a corresponding read-write device. The device can be switched off automatically when the vehicle stops and automatically reactivated as the vehicle begins moving again. Display devices 17 are advantageously installed within the vehicle to alert the driver when driving into a toll zone and to provide a timely, clear indication (similar to a fuel gauge) of the impending depletion of use credit. A continuous display of current use credit is advantageous. Stations 19 at which additional use credit can be purchased for a suitable fee or where a new highway use card can be purchased are preferably provided along the highway routes (e.g., at rest stops, gas stations and parking lots).
If needed, the device according to the invention enables highly differentiated use billing which can also take into account the intensity of use (e.g., it can detect the duration of travel within a toll zone). For this purpose, special possibilities can be provided for input of corresponding parameters. For instance, a sensible variant would be to apply lower rates for individual sections of road or for the entire highway system during off-peak traffic times (e.g., based on season or evening hours) in order to reduce traffic at peak periods by a suitable shifting of traffic.
Unauthorized use of toll sections or zones can be prevented and such improper use can be monitored in an advantageous manner by an outwardly acting signal device 18 (e.g., an h-f transmitter, r-f transmitter, laser diode for infrared signals, etc.) which operates and transmits an "OK" signal when the billing procedure is properly followed and proper use is made of the roads. Externally arranged reception stations (e.g., installed in monitoring vehicles used on the highway exits) can accordingly detect vehicles in which there is no fee detection system or in which the installed system is not being operated properly, that is, when the required fee is not paid. As an alternative or in addition to this, an outwardly acting signal device (e.g., a colored warning light) can be automatically activated when travel within a toll region is extended after the use credit has been exhausted. In such cases, a radio signal which allows the vehicle to be identified can also be sent to a monitoring station. In these cases, the extent of unauthorized use of the highway can be recorded on the mobile storage module for purposes of local traffic patrols.
A substantial advantage of the solution according to the invention consists in that it requires new installation of infrastructure only to a negligible extent, if at all, and enables the use of existing arrangements, that is, arrangements which are installed independently from the respective zone which is subject to use billing. A further important advantage consists in that instances of use subject to charges are determined and calculated in the vehicle automatically so as to provide favorable conditions with respect to protection of data and to exclude unwanted monitoring of driving behavior. No information remains in storage which could enable identification of the total distance traveled by the respective vehicle within the toll region. The temporarily stored information about traveled distances is erased after the use charge has been deducted from the use credit. The coordinates of the last identification point passed by the vehicle which represents the beginning of the route currently being traveled over are filed in the storage each time. However, when necessary, special logging devices which carry out continuous documentation of all traveled distances can be provided, if expressly desired, in order to keep a travel log automatically, e.g., for transportation companies.
As was already mentioned above, use of the arrangement according to the invention is in no way restricted to road traffic, but rather is transferrable to many other applications.
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A use billing system with an arrangement for identifying distances traveled by a moving object within a system of traveled distances or for identifying fixed geographical zones entered by the object. In order to provide a billing arrangement which is universally applicable as far as possible and which requires little expenditure on infrastructure, a system is provided which is installed independently for wireless transmission of information to detect the current geographical position of the object. The moving object carries a reception system to receive the information transmitted over the air and a storage device for temporary storage of data. A second storage device for permanent storage of predetermined data is also carried. The object further carries a comparison device for comparing these data. An identification device is carried by the object for identifying the respective traveled distance. A mobile storage module which can be connected with the identification device by computer techniques is also provided.
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BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a method for processing a signal provided by a bidirectional sensor as well as to a device for the implementation of such a method.
The field of the present invention is more particularly the field of the management of signals provided by sensors in an engine of a vehicle, for example an automotive vehicle, so as to determine parameters of the engine with a view to managing the proper operation of the latter.
Description of the Related Art
In an internal combustion engine, there is generally at least one movable piston for varying the volume of a combustion chamber. Admission and exhaust of fluids in combustion chambers are usually carried out with the aid of poppet valves controlled by at least one camshaft. The energy developed in the combustion chambers by combustion of a fuel within an oxidant is transmitted by each piston to a crankshaft.
For the management of the internal combustion engine, it is important to know the “phasing” (also called “synchronization”) of the engine. The term “phasing” refers to the precise determination of the stroke of the engine cycle (for an internal combustion engine of 4-stroke type they are: admission, compression, combustion, exhaust) which the engine is in for each of its cylinders. The precise position within a stroke of the engine cycle is usually established by determining the position of the crankshaft. However, for an internal combustion engine of 4-stroke type, the duration of an engine cycle in a combustion chamber corresponds to two complete revolutions of the crankshaft. Thus, to ascertain the phasing of an internal combustion engine of this type, an additional item of information is necessary. It is then customary to obtain this item of information on the basis of a camshaft position sensor. Indeed, a camshaft has a rotation speed corresponding to half the rotation speed of the corresponding crankshaft and, therefore, traverses only one revolution over the duration of a complete 4-stroke engine cycle.
Customarily, the position sensor corresponding to the crankshaft cooperates with a target comprising a large number of teeth (generally thirty-six or sixty, without taking account of one or two missing teeth making it possible to define an origin on the target) while the target used in cooperation with the camshaft sensor exhibits only few teeth (for example four). The signal provided by the sensor corresponding to the crankshaft is then used to precisely ascertain the position of the crankshaft (and therefore of the pistons).
However, when the signal of this sensor is defective or noisy, provision is made to use the signal emanating from the sensor corresponding to a camshaft in degraded mode.
The signals provided by the sensors corresponding to the crankshaft and to at least one camshaft are injected into an electronic device, such as for example a generic timer module GTM. Within this module, a digital phase locked loop DPLL is provided for managing the synchronization of the engine position and generating an angular clock.
While the engine is stopping, the crankshaft oscillates about an equilibrium position corresponding to the engine stopping position. If it is desired to then rapidly start the engine after it has stopped, it is important to precisely ascertain the engine stopping position. Novel position sensors, also called bidirectional sensors, are making it possible, on the one hand, like the sensors of the prior art, to detect an edge corresponding to a tooth but also, on the other hand, to determine the direction of rotation of the corresponding target. A strategy integrated into the digital phase locked loop makes it possible to take account of the item of information relating to the direction of rotation of the target and thus to ascertain the position of the engine when the latter stops.
A bidirectional sensor of known type, for example from document JP 2005 233622, provides signals exhibiting an active level and an inactive level. The duration of active level depends on the direction of rotation of the target. For example, a double duration of active level can be chosen for a reverse rotation with respect to the duration of active level for a rotation in the usual direction. It is thus possible to determine for each new edge the corresponding direction of transit. A corresponding strategy in the digital phase locked loop is then used for the realization of the angular clock.
However, there exist bidirectional sensors operating according to another principle. The direction of rotation of the target is given in the signal by varying for example the voltage corresponding to the active level and/or to the inactive level. Such a sensor is also known from document JP 2005 233622, FIG. 6, whose signal comprises four different levels.
BRIEF SUMMARY OF THE INVENTION
The aim of the present invention is then to provide a method for processing a signal provided by a bidirectional sensor which makes it possible to provide an angular clock with a sensor giving an indication of the direction of rotation of the corresponding target, for example through a variation in voltage of the active level and/or of the inactive level, while the digital phase locked loop used is programmed to detect different durations of active level. Preferably, the method according to the invention will make it possible to carry out a reliable determination of the angular position of the corresponding engine. Furthermore, advantageously, the modifications to be afforded at the level of the corresponding electronic device will be limited.
For this purpose, the present invention proposes a method for processing a signal provided by a bidirectional sensor detecting the transit of teeth of a target with a view to generating an angular clock of an internal combustion engine with the aid of a first electronic component receiving the signal originating from the bidirectional sensor, said first component exhibiting means for determining, in a signal exhibiting low-level segments and high-level segments, whether the length of a segment of a given level is or is not greater than a predefined threshold, and the signal provided by the bidirectional sensor being a signal in the form of slots comprising at least low-level segments, high-level segments, and intermediate-level segments, each slot corresponding to the transit of a tooth of a target in front of the sensor and the signal also comprising characteristics making it possible to determine the direction of transit of the tooth.
According to the present invention, such a processing method comprises the following steps:
generation of a first signal utilizing all the slots of the signal provided by the sensor but exhibiting only segments corresponding to a first level and segments corresponding to a second level, generation of a second signal utilizing the slots of the signal provided by the sensor and corresponding to a first direction of transit of a tooth in front of the sensor, and exhibiting a constant level during the rotation of the target in the second direction of transit, generation of a third signal utilizing the slots of the signal provided by the sensor and corresponding to a second direction of transit of a tooth in front of the sensor, and exhibiting a constant level during the rotation of the target in the first direction of transit, connection of the first signal to the input of the first electronic component, connection of the second signal and of the third signal to a second electronic component, detection by the second electronic component of rising and/or falling edges of the second signal and of the third signal, change of the value of the predefined threshold in the first component when the second electronic component detects an edge on one of the two signals connected to the second component whereas the previous edge has been detected on the other signal, the threshold value being able to take either a first predefined value termed the maximum value or a second predefined value termed the minimum value in such a way that the length of the slots is always on one and the same side of the corresponding threshold (one in one direction and the other in the other).
The idea at the origin of the present invention is therefore, on the one hand, of adapting the signal so as to render it compatible with the component and, on the other hand, of changing the threshold value used by this component. In this way, the component becomes compatible with several bidirectional sensors. Furthermore, the adaptation of one sensor to another, as emerges from the description hereinafter given with reference to the appended figures, can be done while limiting the amount and the cost of the hardware means necessary for said adaptation.
In one embodiment of the method according to the invention, the third signal is for example obtained by taking the difference between the first signal and the second signal. In this manner the means to be implemented to obtain this third signal are limited.
To facilitate the implementation of the processing method according to the invention, the detection of rising and/or falling edges of the second signal and of the third signal is carried out by carrying out the detection on one signal, and then, as soon as a sought-after edge is detected, the detection is carried out solely on the other signal, until a sought-after edge is detected thereon. In this way, it is needless to permanently monitor two signals.
The present invention also relates to an electronic device exhibiting means for the implementation of each of the steps of a processing method such as described hereinabove.
In one embodiment of an electronic device such as this, a generic timer module inside which are embedded the first component and the second component, as well as at least one third component outside the generic timer module for generating the second signal and the third signal can be envisaged.
In an electronic device according to the invention, the first component is for example a phase locked loop, especially a digital phase locked loop (DPLL).
Finally, the present invention also relates to a management system of an internal combustion engine, noteworthy in that it comprises an electronic device such as described hereinabove as well as at least one bidirectional sensor.
BRIEF DESCRIPTION OF THE DRAWINGS
Details and advantages of the present invention will emerge better from the description which follows, given with reference to the appended schematic drawing in which:
FIG. 1 illustrates a generic timer module that can be used for the implementation of the present invention,
FIG. 2 illustrates a threshold value used in a component of the module of FIG. 1 ,
FIG. 3 illustrates a detection of direction of rotation of the prior art,
FIG. 4A illustrates a first signal provided by a bidirectional sensor and three signals obtained on the basis of this first signal,
FIG. 4B illustrates a second signal provided by a bidirectional sensor as well as three signals obtained on the basis of this second signal,
FIG. 5 schematically illustrates a step that can be implemented in the present invention,
FIG. 6 is a flowchart that can be used for the implementation of the present invention, and
FIG. 7 schematically illustrates an implementation of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a generic timer module, subsequently called GTM. Such a module can be used within an internal combustion engine electronic management system. Inside this module is a first component 2 charged with managing the synchronization of the position of the corresponding engine as well as with generating an angular clock. This first component 2 is for example a digital phase locked loop (DPLL).
The first component 2 is known from the prior art. It generally receives two signals originating from sensors (not represented) embedded in the corresponding engine. A first signal originates from a sensor associated with a toothed target fastened to the crankshaft of the engine. Such a target generally comprises thirty-six or sixty teeth (without taking account of one or two missing teeth making it possible to introduce a discontinuity defining an origin point on the target), thereby yielding a precise signal to define the position of said crankshaft. The second signal used in the prior art with the first component 2 is a less precise signal originating for example from a sensor associated with a target rotating with a camshaft of the engine. However, as the rotation speed of a camshaft corresponds exactly to half the rotation speed of the crankshaft, the received signal originating from the camshaft makes it possible to ascertain the position of the engine over 720°, also called “phasing” or “synchronization” of the internal combustion engine.
For certain engines it is necessary to precisely ascertain the position of the engine when the latter has stopped. Now, when the engine stops, the crankshaft oscillates mechanically about its equilibrium position in which it will ultimately stop. The crankshaft then turns alternately in one direction and then in the other.
By convention, in the subsequent description the direction of rotation corresponding to the direction of rotation of the engine when running will be called the forward (or FW) direction of rotation. The opposite direction of rotation will be called the backward (or BW) direction of rotation.
In order to determine the position of the engine when stopped, it is required not only to detect the teeth of a target transiting in front of the corresponding sensor but also the direction of transit of these teeth. For this purpose, there exist sensors termed bidirectional sensors which provide a signal which, on the one hand, makes it possible to detect the transit of each tooth and, on the other hand, give an indication about the direction of transit of the corresponding tooth.
FIG. 3 illustrates an exemplary signal provided by a bidirectional sensor. It is noted that this signal is formed of slots of two different types. On the left of FIG. 3 are first slots of reduced length. Thereafter there is a dashed line 4 indicating here a change of direction of rotation of the internal combustion engine. To the right of this dashed line 4 , the slots of the signal represented are of bigger width. Thus there are narrow slots and wide slots. FIG. 2 allows comparison of a narrow slot with a wide slot.
Each slot of the signal illustrated in FIG. 3 exhibits a first active edge 6 . The latter is used for the management of the angular clock generated within the first component 2 . The length of the slot is thereafter used to determine the direction of rotation of the tooth in front of the corresponding sensor. The first component 2 is indeed programmed so as, on the one hand, to detect the first active edge 6 and, on the other hand, to determine the length of the slot. A threshold value, called THMI, is recorded in a register of the first component 2 . As long as the length of the slot remains below the value THMI, the first component considers that the tooth has transited in front of the sensor in the forward direction of rotation. In the converse case, it considers that the tooth has transited in front of the sensor in the backward direction of rotation.
In FIG. 3 is thus represented a signal corresponding firstly to the transit of three teeth in front of the corresponding sensor in the forward direction of rotation. The dashed line 4 illustrates, as mentioned above, the change of direction of rotation of the crankshaft, and therefore of the target associated therewith. The following tooth then transits in front of the sensor traveling backwards. One is therefore dealing with the tooth which has just transited in front of the sensor traveling forwards, just before the change of direction of rotation of the crankshaft. The detection by the first component of the change of direction illustrated by the dashed line 4 is carried out only when the corresponding slot has been analyzed by the first component 2 , that is to say substantially at the date illustrated schematically in FIG. 3 by the arrow 8 . The second edges 10 of the slots of the signal illustrated in FIG. 3 are considered to be inactive edges since they do not correspond to a change of shape on the target. However, these second edges 10 are used for determining the direction of rotation of the crankshaft.
This prior art detection strategy works. However, novel bidirectional sensors with different modes of operation from that described hereinabove are appearing and are
providing signals of different shapes from those shown in FIG. 3 . The problem that the present invention proposes to solve is to allow the use of the first component 2 to generate an angular clock with signals of a different type from that illustrated by FIGS. 2 and 3 .
It is assumed by way of illustrative but nonlimiting example that the signals provided by a novel bidirectional sensor are of the type of the signals CRK of FIGS. 4A and 4B . It is noted that these signals are in the form of slots. However, whereas the signals illustrated in FIGS. 2 and 3 exhibited only a bottom level and a top level, it is noted that the signals CRK of FIGS. 4A and 4B comprise low-level segments 12 , high-level segments 14 and intermediate-level segments 16 . The low level corresponds for example to a voltage of 0 V, the high level for example to a voltage of 5 V while the intermediate level can correspond to a voltage of 2.5 V. In a signal CRK, when the voltage difference at the level of a slot is of the order of 5 V, this signifies that the tooth transits in front of the sensor in the forward direction of rotation. When the voltage difference at the level of a slot is of the order of 2.5 V, this then signifies that the tooth transits in front of the corresponding sensor in the backward direction of rotation.
In FIGS. 4A and 4B a chain-dotted line 4 ′ has been represented which corresponds to a change of direction of the crankshaft for two distinct sensors. The signal CRK of FIG. 4A corresponds to a first type of sensor which provides a signal of level 0 V and 2.5 V for a reverse rotation and the signal CRK of FIG. 4B corresponds to a second type of sensor which provides a signal of level 2.5 V and 5 V for a reverse rotation. As a function of the sensor, the active edge of a slot of the signal can be either the first rising edge, or the second falling edge. In FIGS. 4A and 4B , the active edges are labeled by an arrow on the signal. It is noted here that the active edges of the signals CRK are the falling edges.
It is clearly noted that signals of this type cannot be processed as is by the first component 2 . The present invention proposes to render such signals compatible with the first component 2 described above.
It is proposed here to process the signal obtained by the bidirectional sensor so as to generate three distinct signals called in FIGS. 4A and 4B CRK_CNT, CRK_FW and CRK_BW.
The first signal CRK_CNT utilizes all the rising edges and the falling edges of the signal CRK and thus forms slots. Here, however, provision is made for the signal CRK_CNT to have only low-level segments and high-level segments. The low level can correspond to a voltage of 0 V while the high level can correspond to a voltage of 2.5 or 5 V for example.
The second signal CRK_FW is a signal similar to the signal CRK_CNT but for which the slots corresponding to transits of teeth in the backward direction of rotation are “erased”. This second signal CRK_FW is therefore such that when the crankshaft rotates backwards, the level of this second signal CRK_FW is constant. As illustrated in FIGS. 4A and 4B , the constant level can be either the low level or the high level.
The third signal CRK_BW generated on the basis of the signal CRK exhibits, in a similar manner, slots only when the crankshaft rotates in the backward direction of rotation. A signal of constant level is therefore found when the crankshaft rotates in the forward direction of rotation and slots corresponding to transits of teeth in front of the sensor when the crankshaft rotates in the backward direction of rotation. It may be noted here that this third signal CRK_BW may be obtained by differencing between the signal CRK_CNT and the signal CRK_FW.
It is proposed that the first signal CRK_CNT be injected on a first input 18 of the first component 2 . This first input 18 is that provided for receiving a signal of the type of that illustrated in FIG. 3 . The first signal CRK_CNT is then injected on second input 20 of the module GTM at the level of an electronic component of second component 24 type. The latter automatically retransmits, without lag, the signal received on the first input 18 of the first component 2 .
The second signal CRK_FW and the third signal CRK_BW are injected respectively onto a third input 22 and a fourth input 23 of the module GTM. The second signal CRK_FW and the third signal CRK_BW are each then injected into an electronic component of second component 24 type which is intended to detect the edges of the signals that it receives it its input. Both for the second signal CRK_FW and for the third signal CRK_BW the second components 24 can thus detect the active edge of each of these signals (here this may be the rising edge or the falling edge but in the typical case represented it is the falling edge).
It should be noted here that for their processing, the signals may, if necessary, be filtered. It will then be appropriate to take care to limit the duration (delay) of the filter.
The item of information, provided by the second components 24 , regarding level is dispatched directly to a sequencer 26 of the module GTM by way of a transmission module called in FIG. 1 ARU. Each sequencer 26 is permanently on standby awaiting a first edge indicating a change of direction. Having regard to the characteristics of the second signal CRK_FW and of the third signal CRK_BW, it is proposed here that after a detection of an active edge on one signal (CRK_FW or CRK_BW), the other signal (CRK_BW or CRK_FW) is observed so as to detect on the latter the first active edge which arrives. The latter informs of the change of direction of
rotation. FIG. 5 illustrates change-of-direction edges 28 on an example of signals CRK_FW and CRK_BW.
Thus, upon each detection of change of direction, the sequencer 26 changes signal so as to prepare itself for the next change of direction. Furthermore, the sequencer 26 then uses a software interrupt request associated with this sequencer. This interrupt request is carried out at an electronic component external to the GTM. This external component is for example a component of the DMA (“Direct Memory Access”) type. The interrupt at the DMA component is associated with an automatic transfer which is used to vary the value of the register THMI defined above, with reference especially to FIG. 2 .
In the associated electronic memory, a buffer memory, or just buffer, contains two values. It is proposed here that values THMI_MIN and THMI_MAX be chosen as values for the buffer memory.
A first value, for example THMI_MAX, of the buffer memory corresponds to the maximum value that can be taken by the register THMI. When it is recorded in the register THMI, this value will always be greater than the tooth duration measured and which is compared with the THMI. It is then considered, by default, that the target is rotating forwards.
The second value, THMI_MIN, is a value intentionally chosen to be very low so that the first component 2 then sees all the slots as being wide slots, that is to say having a greater width than the threshold width. In the present case, THMI_MIN will be able to take for example the value “1” since it is assumed that the value “0” is used to totally deactivate the direction detection strategy. In this typical case, as explained above, it is therefore considered that the target transits in front of the bidirectional sensor in the backward direction of rotation.
Thus, whenever a software interrupt is requested, passing via the component of DMA type, the value of the register THMI is modified instantaneously, thus switching successively from the value THMI_MIN and then THMI_MAX, and so on and so forth. The time to perform a change of the value of the register THMI is very short and remains less than the duration of the active level. Thus the value of this register is changed before the inactive edge is processed using said value. Likewise, if a detection is made on an inactive edge, the change of register value will be effective for the following active edge. All the steps described relating to the change of value in the register THMI, from the detection of the active edge on one of the signals indicating a change of direction, are carried out instantaneously and do not cause any delay. There is therefore a shiftless updating of the first component 2 when a change of direction is detected. Other means may be implemented to change the value of the register THMI. Software processing within an associated microprocessor may for example be envisaged. In an internal combustion
engine management system, this solution can be envisaged since the detection of reverse direction of rotation is performed only when the engine stops, that is to say at very low revs, and therefore at a moment when the software loading is low.
FIG. 6 presents in the form of an algorithm a processing of the detection of the change of direction within the sequencer 26 . A first step 30 is an initialization step. The direction detection begins only if the system is ready to operate. Upon starting an engine, the latter is always propelled in the same direction which corresponds to the forward direction of rotation. Upon starting, the sequencer 26 therefore considers the target to be rotating in the forward direction of rotation. In the course of step 32 it analyzes the signal CRK_BW transmitted by the ARU on standby awaiting an active edge on this signal. During this detection, the ARU may receive a command from an associated microprocessor (box 34 ) requesting cessation of operation and therefore the detection of direction of rotation. A step 36 is then provided for halting the detection of direction of rotation of the crankshaft. This solution may correspond for example to the typical case in which the engine stalls or in case of loss of synchronization or phasing. In this case, the initialization process (step 30 ) is relaunched.
As long as no command is received from the associated microprocessor, the monitoring continues until detection of an active edge on the signal CRK_BW is obtained (step 38 ). During this step 38 , a software interrupt is requested and the latter leads to a change of the value of the register THMI. In the above numerical example, the register THMI then takes the value THMI_MAX.
The sequencer 26 then passes immediately and without lag to the next step 40 . This step corresponds to step 32 described previously but here the sequencer 26 is on standby awaiting an active edge on the signal CRK_FW. In a manner similar to what was described above (box 34 ′) the detection can be stopped on command of an associated microprocessor. In case of stoppage, the sequencer 26 passes to step 36 as explained previously.
When an active edge is detected on the signal CRK_FW (step 42 ), a software interrupt is triggered and orders the change of the value of the register THMI. The latter then takes the value THMI_MIN in the numerical example given above. The change of direction is then recorded by the first component 2 and the sequencer immediately returns to step 32 of detection on the signal CRK_BW.
FIG. 7 illustrates the present invention with the aid of the signals generated on the basis of the signal provided by the bidirectional sensor. Chain-dotted lines 4 ′ corresponding to changes of direction have been represented in this figure. On the left of the figure, it is assumed that the target is rotating backwards. The directions of rotation (BW for backward and FW for forward) are mentioned at the top of FIG. 7 .
The signal CRK_CNT is represented. It exhibits a slot shape and an arrow each time representing the active edge of a slot. For the present illustration, the teeth of the target have been numbered with letters of the Latin alphabet.
Below the signal CRK_CNT are the signals CRK_FW and CRK_BW. On these signals, an arrow indicates the active edges allowing detection of a change of direction. Below the signal CRK_BW, a chart illustrates the values taken by the register THMI. To each edge corresponding to a change of direction detected on the signals CRK_BW and CRK_FW there corresponds a change of the value of the register THMI.
The last line in FIG. 7 corresponds to the processing done by the first component 2 (DPLL). The signal received by this first component corresponds to the signal CRK_CNT which is injected into the first input 18 of this component. Arrows 44 illustrate the detection of the change of direction by the first component 2 . It is noted that this detection of change of direction is carried out with a delay of one tooth. On account of the detection delayed by the first component 2 of the change of direction, it is appropriate to correct the number of the tooth detected by the first component 2 just before detecting the change of direction. These automatic corrections 46 are illustrated at the bottom of FIG. 7 . Thus, the first component 2 correctly analyzes the signal received and can provide an exact angular clock.
The main advantage presented by the solution proposed by the present invention is that of allowing the use of a component adapted for processing a type of signal provided by one bidirectional sensor to another bidirectional sensor providing different signals. The internal strategy of the digital phase locked loop for detecting a change of direction is unchanged.
This adaptation is carried out here while limiting the electronic means to be implemented to carry out this adaptation. The electronic hardware necessary here corresponds only to the means for processing the signal of the bidirectional sensor. Such means cost much less than the development and the fabrication of an electronic component integrating an adapted software solution (ASIC).
The solution proposed here has the advantage furthermore of having no impact on the loading of a microprocessor. The solution described hereinabove uses only the internal resources of the generic timer module (GTM), in conjunction with the component of DMA type. This also has the advantage of having immediate processing which eliminates any risk of uncontrolled desynchronization related to a delay in the change of configuration of the digital phase locked loop.
The strategy proposed here is flexible. It can adapt to various types of bidirectional sensors, especially diverse types of sensors with variable voltage and with
different types of behavior in case of change of direction. Furthermore, as emerges from the preceding description, it can also adapt to the hardware environment. It may be noted here that this flexibility could not be achieved with the use of an ASIC (“Application-Specific Integrated Circuit”).
Of course, the present invention is not limited to the embodiment described hereinabove by way of nonlimiting example and to its variant embodiments mentioned. It also relates to all variant embodiments within the scope of the person skilled in the art from this description.
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A method and device for processing a signal (CRK) provided by a bidirectional sensor, the method includes the following steps:
generation of a first signal (CRK_CNT) utilizing all the slots of the signal provided by the sensor, generation of a second signal (CRK_FW) utilizing the slots corresponding to a first direction of transit, generation of a third signal (CRK_BW) utilizing the slots corresponding to a second direction of transit, connection of the first signal to the input of the first electronic component, connection of the second and third signals to a second component, detection by the second component of edges of the signals received, change of the value of the predefined threshold (THMI) in the first component upon each detection of an edge.
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FIELD OF THE INVENTION
The present invention relates generally to devices and methods for pulling of metal fence posts or the like from the ground, and more particularly to a solution employing pivotal cam-shaped grippers that are actuated by application of an upward pulling force on the post puller by the lifting arrangement of a working machine.
BACKGROUND
Metal (typically steel) posts or pickets are commonly employed for temporary fencing measures, and most commonly feature a T-shaped, t-shaped, Y-shaped, or star-shaped cross section. In a common temporary fencing setup, a series of posts are driven into the ground at spaced apart positions along the intended fence line, and then wire mesh is strung up between adjacent posts using a series of teeth that are provided on a flange or web of the post. When it becomes desirable to take down or relocate the fence, the mesh is removed and rolled up, and the posts are pulled free of their previously embedded positions in the ground.
A number of devices have been previously proposed for the purpose of pulling posts from the ground, including those disclosed in U.S. patents U.S. Pat. No. 1,774,661, U.S. Pat. No. 4,422,621, U.S. Pat. No. 4,721,335, U.S. Pat. No. 5,011,117, U.S. Pat. No. 5,368,277, U.S. Pat. No. 7,059,587, U.S. Pat. No. 7,290,754, U.S. Pat. No. 7,963,051, U.S. Pat. No. 8,608,132 and U.S. Pat. No. 8,453,993; U.S. Patent Application Publications US2007/0183121, US2012/0279737 and US20090028649; and PCT Publication WO2012116405.
Of these references, U.S. Pat. No. 1,774,661 and U.S. Pat. No. 8,453,993 employ a cam-based post gripping mechanism that is most comparable to that of the present invention, but rely on manual levers to provide the post gripping and pulling forces required to grip the post and pull it free from the ground. Other references make use of external equipment to provide the lifting and gripping force, but not in a manner compatible with a cam-based gripping mechanism like that employed in the present invention.
Applicant has therefore developed a unique solution for actuating post grippers of a post puller using a skid steer, front end loader, excavator, back hoe or other working machine with a powered lifting arrangement.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a post puller for pulling a post from a ground embedded position standing upright from a ground surface, the post puller comprising:
a lifting member having a coupling point thereon that is configured for attachment to lifting arrangement of a working machine to enable upward lifting of said lifting member by the lifting arrangement of the working machine;
a sliding sleeve attached to the lifting member;
a guide shaft about which the sliding sleeve is disposed for axial sliding of the sleeve up and down along a longitudinal axis of the guide shaft;
a pair of movable grippers pivotally supported on the guide shaft by respective pivotal connections on opposing sides of a central longitudinal plane thereof at a fixed location along the longitudinal axis of the guide shaft, each movable gripper having an inner end with a cam-shaped gripping surface that faces across the central longitudinal plane of the guide shaft toward the cam-shaped gripping surface of the other movable gripper, and an opposing outer end spaced laterally outward to a respective side of the guide shaft, each cam-shaped gripping surface increasing in a radial distance thereof from a pivot axis of the respective pivotal connection in a direction moving upward from an imaginary axis intersecting the pivot axes of the pivotal connections;
a pair of links having upper ends pivotally coupled to the lifting member and respective lower ends each pivotally coupled to a respective one of the movable grippers proximate the outer end thereof, whereby raising of the lifting member by the working machine with a web or flange of the post received in a space between the inner ends of the movable grippers lifts the outer ends of the movable grippers via the pair of links, thereby lowering the inner ends of the grippers about the pivot axis and bringing the cam-shaped gripping surfaces into closer proximity to one another to grip the web or flange of the post between the gripping surfaces and pull the post from the embedded position under further raising of the lifting member by the working machine.
Preferably there are provided upper and lower braces situated above and below the movable grippers on a same side of the guide post as said movable grippers, each brace defining a slot for receiving the web or flange of the post therein to align the web or flange in the space between the inner ends of the grippers.
Preferably there is provided a ledge projecting outward from the guide shaft to a same side thereof at which the movable grippers are disposed for resting of said ledge atop the post during placement of the post puller in an operational position situating the web or flange of the post in the space between the inner ends of the grippers.
Preferably the ledge resides at a position above the upper brace.
Preferably the lower brace resides below the fixed position of the movable grippers at a further distance therefrom than the upper brace.
Preferably there is provided at least one handle attached to the guide shaft.
Preferably the at least one handle extends to a side of the guide shaft opposite the movable grippers.
Preferably the at least one handle comprises a pair of handles each extending laterally outward from the post to a respective side thereof in opposing directions away from the central longitudinal plane of the guide shaft.
Preferably each handle comprises an open grip handle having upper and lower arms attached to the guide shaft at spaced apart positions along the longitudinal axis, a central span joining the upper and lower arms together at a radial distance outward from the guide shaft, and an open space bound between the arms, the central span and the guide shaft for gripping of the handle through said open space.
According to a second aspect of the invention, there is provided a method of pulling a post from a ground embedded position standing upright from a ground surface, the method comprising:
(a) positioning the post puller according to anyone of claims 1 to 9 in an operating position in which the web or flange of the post is received in the space between the movable grippers;
(b) supporting the post puller in the operating position independently of the lifting member thereof such that lifting member and links are gravitationally biased downward to push downwardly on the outer ends of the gripping members and raise the inner ends of the gripping members into an open position maximizing the space between the cam shaped gripping surfaces of the gripping members;
(c) pulling upwardly on the lifting member using the lifting arrangement of the working machine, and thereby displacing the sliding sleeve upwardly along the guide shaft and pivoting the movable grippers in a direction moving the cam-shaped gripping surfaces closer together and into frictional engagement with the flange or web received in the space between the gripping surfaces; and
(d) with the flange or web frictionally gripped between the gripping surfaces of the movable grippers, pulling the lifting member further upward using the lifting arrangement of the working machine, thereby pulling the post out of the embedded position.
Supporting the post puller independently of the lifting member in step (b) preferably comprises seating the post puller atop the post at an upper end thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:
FIG. 1 is an elevational front view of a post puller of the present invention in a ready state for acceptance of a web or flange of a post (not shown) between two movable grippers of the puller.
FIG. 2 is an elevational front view of the post puller in an actuated state gripping state in which gripping surfaces of the grippers have been brought together for the purpose of gripping the web or flange of the post (not shown) between the grippers.
FIG. 3 is an elevational side view of the post puller.
FIG. 4 is a rear elevational view of the post puller in the ready state.
FIG. 5 is a perspective view of the post puller in the gripping state during use, in which the post puller is lifted by a cable, strap, or line coupled to the lifting arms of a skid steer, front end loader, excavator, back hoe, or other working machine.
In the drawings like characters of reference indicate corresponding parts in the different figures.
DETAILED DESCRIPTION
FIGS. 1 to 4 illustrate a post puller 10 according to one embodiment of the present invention, which is generally made up of a upright guide shaft 12 , a hollow sliding sleeve 14 , a lifting member 16 , a pair of links 18 , a pair of movable grippers 20 , a pair of braces 22 , a resting ledge 28 and a pair of handles 26 . The terms vertical and horizontal are used herein in relation to the illustrated orientation of the post puller shown in the drawings, in which the guide shaft 12 stands vertically upright so as to lie parallel to a vertical fence post when used thereon. However, in actual practice, fence posts will of course not always stand truly vertical, and so the orientation of the tool will likewise deviate from the vertical orientation described and shown. The terms horizontal and vertical are therefore used only to distinguish the components that lie more vertical than horizontal from those that lie more horizontal than vertical.
The guide shaft 12 and sliding sleeve 14 are both formed of rectangular metal tubing, and the sliding sleeve 14 has a slightly larger cross-sectional area and is concentrically disposed around the guide shaft 12 for sliding movement upwardly and downwardly therealong in the upright longitudinal direction of the shaft 12 . A resting ledge 28 in the form of a small flat horizontal plate welded or otherwise attached to the shaft extends forwardly therefrom at a distance below the top end of the shaft 12 . The sliding sleeve is disposed around the shaft 12 at the portion thereof residing above this resting ledge 28 . The ledge 28 thus defines a stop that prevents the sleeve 14 from sliding downwardly past the ledge 28 , thereby constraining the sleeve's range of travel to an upper portion of the guide shaft 12 .
The lifting member 16 is a flat plate welded or otherwise attached to the front side of the sliding sleeve 14 in a position residing parallel thereto at a short distance forwardly outward therefrom. A coupling point 30 is provided near the top of the lifting member 16 in the form of a through-hole passing horizontally therethrough. Near two lower corners of the lifting member 16 , the two links 18 are respectively coupled to the front face of the lifting member 16 by respective pivot pins 32 passing horizontally through the lifting member 16 in the same direction as the coupling point through hole 30 . As a result, each link 18 is pivotal about a horizontal pivot axis that passes perpendicularly through the lifting member plate 16 . The links are therefore pivotal within a vertical plane lying parallel to the lifting member plate 16 on the front side thereof opposite the shaft 12 .
At an intermediate location along the length of the shaft 12 , a mounting bracket 34 is welded or otherwise attached thereto in a position jutting outwardly from the shaft 12 on at least the front and lateral sides thereof. At a front end of the bracket 34 , each one of the movable grippers 20 is pivotally coupled thereto by a respective pivot pin 36 that passes horizontally through the mounting bracket 34 on a respective side of the shaft 12 in a direction parallel to the pivot pins 32 at the upper ends of the links 18 . A respective cotter pin 38 or other suitable locking secures each of the pivot pins 36 in place by cooperating with the head 36 a of each pivot pin 36 at the other end thereof to prevent sliding of the pivot pin out of the mounting bracket 34 in either direction. This set of pivot pins 36 cooperates with the mounting bracket 34 affixed on the shaft to pivotally mount the movable grippers 20 on the shaft, and therefore may also be referred to herein as mounting pins 36 in order to better distinguish same over the other pivot pins used elsewhere in the assembled post puller.
Yet another pair of pivot pins 36 are used to pivotally connect the movable gripping members 20 to the links 18 that hang downwardly from the lifting member 16 . These pivot pins 36 are also referred to herein as connection pins 40 to better distinguish same over the other pivot pins in the assembled post puller. Each connection pin 40 extends through the respective gripper 20 near the outer end thereof that lies distal to the guide shaft 12 , and lies parallel to the other two sets of pivot pins 32 , 36 . The mounting pins 36 extend through the movable grippers 36 near the inner ends thereof that reside adjacent to a central longitudinal plane of the shaft 12 on opposite sides of this central longitudinal plane. The inner end of each movable gripper 20 is curved non-concentrically around the axis of the respective mounting pin 36 to create a cam-shape that increases in its radial distance from the mounting pin axis in a direction moving upward from an imaginary horizontal axis that perpendicularly intersects the axes of the mounting pins 36 . An upper portion of the inner end of each gripper 20 is serrated to define a series of gripping teeth, therefore defining a gripping surface 20 a that faces toward that of the other gripper across the gap or open space left between the inner ends of the grippers.
An upper brace 22 a of the post puller resides at a location below the resting ledge 28 and above the mounting bracket and movable grippers. The brace 22 features a small horizontal plate welded or otherwise attached to the shaft 12 in a position projecting forwardly outward from the front side thereof on the same side of the shaft 12 as the linkage formed by the lifting member 16 , links 18 and grippers 20 . A lower brace 22 b likewise projects forwardly from the shaft, but at the lower end thereof situated at a distance below the mounting bracket and movable grippers 20 . Each brace 22 a , 22 b features a linear slot 42 that cuts into the brace plate from the distal end thereof that lies opposite to the shaft 12 , whereby the remaining intact portions of the brace plate on opposite sides of the slot define a pair of tongs. Beneath the ledge 28 , a pair of side walls 44 depend vertically downward from the ledge 28 toward the upper brace 22 a on opposite sides of the shaft 12 . In the illustrated embodiment, the resting ledge 28 , upper brace 22 a and side walls 44 are separately defined by respective plates, but in other embodiments, one or more of these components may be integrally combined into a single piece unit. For example, the resting ledge 28 , upper brace 22 a and side walls 44 may be integrally defined by a piece of rectangular tubing that is laser-cut or otherwise configured into a suitable shape for mounting to the guide shaft.
Completing the structure of the post puller are the pair of handles 26 , each of which is provided in the form of a three-segment bar. Each bar-type handle 26 has a lower arm 26 a jutting horizontally outward from the shaft 12 at or near the lower end thereof at an oblique angle so as to span laterally and rearwardly away from the shaft 12 . A similar upper arm 26 b likewise juts horizontally outward from the shaft at an oblique angle matching that of the lower arm 26 a , but farther up the shaft 12 , for example at the same elevation as the upper brace 22 a . A central span 26 c of each bar-type handle spans vertically between the upper and lower arms 26 a , 26 b thereof to complete an open-handle configuration that features an open handle space 46 bound by cooperation of the arms and central span of the handle with the shaft 12 .
Having defined the structure of the post puller, attention is now turned to the operation of its grippers. Due to the linkage defined by the pivotal connection of the links 18 between the lifting member 16 and the grippers 20 , raising of the lifting member 16 relative to the shaft 12 pulls the outer ends of the grippers 20 upward about the axes of mounting pins 36 , which causes the inner ends of the grippers 20 to pivot downwardly about the axes of the mounting pins 36 . Due to the cam-shaped configuration of the serrated gripping surfaces 20 a of the grippers 20 , this causes the gripping surfaces 20 a to move closer together across the central longitudinal plane of the shaft 12 , thereby reducing the width of the gap or space therebetween. FIG. 1 shows the post puller in its default ready state, where the weight of the sleeve 14 and attached lifting member gravitationally bias the lifting member 16 into a lowered position seated atop the resting ledge 28 . This gravitational action biases the outer ends of the grippers 20 downwardly about the axes of the mounting pins 36 , which in turn biases the gripping surfaces 20 a at the inner ends of the grippers upwardly about these axis, and away from one another. Accordingly, in the default state of the post puller, the gap or space between the gripping surfaces 20 a of the grippers is maximized.
With reference to FIG. 2 , when the lifting member 16 is lifted up relative to the shaft, thereby lifting the sleeve 14 up off of the resting ledge 28 , this lifting action raises the outer ends of the grippers 20 about the axes of the mounting pins 36 , which in turn lowers the inner ends of the grippers about the axes of the mounting pins and thereby forces the serrated gripping surfaces 20 a at the inner ends of the grippers toward the central longitudinal plane of the shaft, thus moving these gripping surfaces closer together to reduce the width of the gap or space between them.
Turning to FIG. 5 , use of the post puller to remove a post 100 from its embedded position in the ground is now described as follows. A user grips the two handles 26 in his or her hands and uses same to manually lift the post puller to a position raising the resting ledge 28 to a height great than the top end of the post 100 . With the slots 42 in the two braces 22 a , 22 b aligned with a web or flange 102 of the post 100 , the post puller is manually displaced in a horizontal direction toward the post from the side thereof to which this web or flange 102 extends, until either the free outer edge of the web or flange bottoms out in the slots of the braces 22 a , 22 b or the distal ends of the prongs of the braces 22 a , 22 b are brought into contact with other flanges of the post 100 . As best seen in FIG. 3 , the distance by which the resting ledge 28 projects from the shaft 12 is greater than the projecting distance of the braces 22 a , 22 b , whereby this horizontal shifting of the braces into engagement with the post acts to place the resting ledge 28 in a position overlying the top end of the post, thereby effectively seating or hanging the post puller on the post 100 . The side walls 44 beneath the resting ledge prevent the post puller from falling laterally off the top end of the post.
Turning back to FIG. 5 , a strap, cable, chain, rope or other flexible lifting line 104 is connected to the lifting member 16 , for example by coupling a clevis 106 to the lifting member 16 by way of a clevis pin 108 fed through the coupling point hole 30 at the top of the lifting member 16 . The other end of the flexible lifting line 104 is securely fastened to the lifting arrangement of a skid steer loader, front end loader, excavator, back hoe or other working machine having a raisable and lowerable lifting arrangement. The lifting line 104 may be coupled to a bucket or other implement mounted on the lifting arms or boom of such a working machine, or coupled directly to the lifting arms or boom if a suitable connection point is found thereon. The flexible lifting line may be connected to the lifting member of the post puller prior to placement of the post puller onto the post, and optionally used to help in the initial lifting of same, provided that the final placement of the post puller onto the post is performed manually so as to leave slack in the lifting line so that the upward pulling force on the lifting member is removed to allow the grippers to move into their default open position in which the gap space between them is greater than the width of the flange or web of the post.
With post puller seated atop the post, as shown in FIG. 5 , the lifting arrangement of the working machine is raised, thereby pulling upward on the lifting member 16 of the post puller to cause the gripping surfaces of the grippers 20 to move toward one another and frictionally grip the web or flange 102 of the post 100 between them, whereupon continued raising of the lifting arrangement of the working machine will pull the post free from the ground.
As best shown in FIG. 3 , each link 18 of the illustrated embodiment is made up of two matching link plates 18 a , 18 b disposed in front of and behind the plane of the lifting member 16 and grippers 20 , but it will be appreciated that each link may alternatively be defined by a single unitary piece. Likewise, although the inclusion of two braces 22 a , 22 b spaced notably apart along the longitudinal direction of the shaft provides an effective stabilizing function to keep the post puller 10 in-line with the post 100 , it may be possible to rely on only a single brace, or to even omit the braces altogether without detriment to the gripping and pull efficiency of the post puller 10 . Likewise, the inclusion or configuration of the handles may vary, although the use of two obliquely oriented handles 26 that extend both rearwardly and laterally from the shaft provide for a confident two-handed grip that is balanced across the shaft while keeping the user's hands well back from the post/puller interface during use to avoid inadvertent injury.
Although the use of rectangular tubing maintains proper alignment of the lifting member and links with the shaft-carried grippers at the front side of the shaft, tubing of other non-circular cross-sectional shape may similarly maintain such alignment by preventing relative rotation between the shaft and sleeve to minimize stress on the linkage. Alternatively, circular tubing may be used, either with suitable anti-rotation means acting between the shaft and tube or relying on the linkage itself to self-maintain alignment between its components. Although a hollow shaft is in the best interest of weight reduction and material efficiency, the invention is not limited specifically to the use of a hollow tubing to define the guide shaft for the sliding movement of the sleeve.
In addition to being usable on the post types mentioned in the background section above in the context of temporary fencing, the present invention can also be used with others post types that similarly have an accessible web or flange engagable by the grippers, for example including angle iron or U-channel posts used for road signage support or other ground-embedded applications.
Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the scope of the claims without departure from such scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense.
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A post puller features a lifting member that is slidably disposed on a guide shaft and attachable to a lifting arrangement of a working machine. A pair of movable grippers are pivotally supported on the guide shaft at a fixed position therealong, and a pair of links are pivotally connected between the lifting member and the grippers. With a web or flange of the post received in a space between inner ends of the movable grippers, raising of the lifting member by the working machine lifts the outer ends of the movable grippers via the pair of links, thereby lowering inner ends of the grippers into closer proximity to one another to grip the web or flange of the post between the grippers. With the post gripped in this manner, further raising of the lifting member by the working machine pulls the post from the ground.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the art of medical systems, and more specifically to managing data communications between multiple independent subsystems forming a safety critical system.
2. Description of the Related Art
Today's safety critical systems, such as automated medical system products, for example surgical equipment, may be constructed as a collection of two or more independent modules or subsystems. Constructing a suite of independent modules affords medical system product designers and manufactures the ability to create and deploy subsystems that perform specific functions that are a subset of functions of the complete device or system.
Designs that take advantage of allocating functions to a plurality of specialized modules must include a communications mechanism to enable the modules to interact with each other. Modules may share or communicate control and status information between each other to realize the entire system functionality. These communications are typically realized using a communications protocol that specifies a uniform or consensus format that the modules or subsystems use to transmit and receive information to each other.
Traditionally, medical system products transmit control and status signals between subsystems over a fixed wire or cable using a standard cable interface, such as Universal Serial Bus, Ethernet, etc. Furthermore, these products frequently employ a variety of standardized communications protocols. Some of the most frequently used protocols include: XModem, ZModem, Kermit, MNP, and CCITT V.42. However, each of these currently available protocols exhibits limitations and restrictions that make them unacceptable in the design of a safety critical system. Each of these protocols may exhibit excessive overhead, high bandwidth, lack of system integrity, limited error detection and error correction, and/or a need for excessive processing resources to execute the protocol.
Current standardized communications protocols are problematic in that they require excessive overhead or additional information that must be transmitted with the original data to facilitate control of the protocol by the sending and receiving modules or subsystems. Excessive communications protocol overhead, or poor protocol efficiency, can require additional transmission media (i.e. fixed wire or cable) bandwidth to realize exchange of control and status information between modules. In addition, the excessive overhead requires additional significant processing resources (i.e. CPU cycles, memory, etc.) to execute the protocol. Moreover, this increase in required bandwidth and processing resources adds to cost and complexity to deliver each module.
A major commercial problem with respect to the above mentioned known communications protocols is the lack of a reliable communications watchdog mechanism. A communications watchdog can effectively trigger a control system, such as a surgical device, to switch to a safe state when a module or subsystem exhibits a fault that may result in a dangerous overall system behavior, that is, loss of control of the surgical instrument and potentially severe harm or even death of the patient. Without the benefit of a communications watchdog, current designs do not provide a sufficient level of system integrity for such safety critical systems as surgical devices. Overall systems integrity is paramount to designing and deploying safety critical systems. Thus, today's designers are faced with a difficult and complex implementation challenge to ensure constant communication between independent modules to provide the required level of safety in an operating theater environment.
Furthermore, the protocol employed in the construction of safety critical systems must provide the ability for two modules to send arbitrary data between themselves and to ensure the integrity of that data. The protocol preferably enables either the transmitter or the receiver to detect that an error in the information has been introduced during the transmission, and enables that error to be corrected via the communications protocol.
Based on the foregoing, it would be advantageous to provide a communications protocol for use in safety critical systems that overcomes the foregoing drawbacks present in previously known protocols used in the design of medical systems.
SUMMARY OF THE INVENTION
According to one aspect of the present design, there is provided a method for establishing communications between at least two independent software modules in a safety critical system. The method comprises providing a media connection between software modules, wherein the software modules employ a communications protocol and participate in a bi-directional master-slave relationship between a master module and a slave module. The method further comprises sending a request message comprising an arbitrary length of data comprising optional data between the master and slave modules, wherein the arbitrary length of data comprising optional data is used by the master module to control and obtain status from the slave module, and the request message further enables the slave module to return data and status information to the master module, and employing a safety critical communications watchdog between the master and slave modules, wherein the safety critical communications watchdog monitors communications quality between the master and slave modules.
According to a second aspect of the present design, there is provided a medical device configured to manage communications therein. The device comprises a plurality of software modules comprising at least two software modules configured in a master-slave relationship, and a media connection between a plurality of software modules. The plurality of software modules are configured to communicate using a bandwidth efficient communications protocol. The plurality of software modules provide a medical event safety critical communications watchdog Function to verify communications integrity over the media connection.
According to a third aspect of the present design, there is provided a bandwidth efficient communications protocol for communicating between software modules in a medical device. The communications protocol comprises bytes transmitted using a packet consisting of a start indication, a message identifier, an optional service identifier, a class identifier, an arbitrary length of data pertinent to the medical device comprising optional data, wherein length of the arbitrary length of data depends upon at least one of the class identifier, message identifier, and optional service identifier, a checksum, and a checksum complement.
These and other advantages of the present invention will become apparent to those skilled in the art from the following detailed description of the invention and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which:
FIG. 1 is a block diagram illustrating the components and interfaces of an exemplary medical system employing the novel communications protocol of the present design;
FIG. 2A shows the data packet byte structure for an explicit request message in accordance with the present design;
FIG. 2B represents the data packet byte structure for an explicit response message in accordance with the present design;
FIG. 2C illustrates the data packet byte structure for an explicit acknowledgement (ACK) message and an explicit not acknowledge (NACK) message in accordance with the present design;
FIG. 3A shows the data packet byte structure for an implicit request message in accordance with the present design;
FIG. 3B illustrates the data packet byte structure for an implicit response message in accordance with the present design;
FIG. 4 is the message flow for Get, Set, Start, Stop, and Shutdown service requests in accordance with the present design; and
FIG. 5 represents the message flow for requesting data in accordance with the present design.
DETAILED DESCRIPTION OF THE INVENTION
The following description and the drawings illustrate specific embodiments sufficiently to enable those skilled in the art to practice the system and method described. Other embodiments may incorporate structural, logical, process and other changes. Examples merely typify possible variations. Individual components and functions are generally optional unless explicitly required, and the sequence of operations may vary. Portions and features of some embodiments may be included in or substituted for those of others.
The present design provides a system and method for managing data communications between multiple independent subsystems in a safety critical system. The present design may provide a serial communications protocol for sending and receiving arbitrary data between two modules and ensuring data integrity. The modules, or subsystems, may perform specific functions that are a sub-set of the complete device or system. With the communications provided by the present design, the modules or subsystems may perform as two independent software entities. Each software entity may provide the applications and the appropriate underlying operating systems software. The present designs communications protocol may enable either module to detect that an error in the information has been introduced during the transmission, and for that error to be corrected via the communications protocol.
This serial communications protocol may be used between two modules in a safety critical system communicating over relatively low bandwidth asynchronous media, for example RS-232 or RS-485 serial cables. The present design may be configured to provide a communications watchdog facility capable of monitoring intra-module communications on a predefined time interval, detecting intra-module communications failures, and taking appropriate safety measures in response to a detected fault. The present design may send data between two modules in the form of packets where the packets are configured to efficiently transmit additional information to facilitate control of the protocol by the sending and receiving modules. In this arrangement, the present design may provide an efficient communications protocol that minimizes the amount of communications bandwidth required to support the transmission of overhead information on the transmitted data.
The present design is directed to managing an accurate, reliable, and efficient arrangement for transmitting and receiving data over a fixed wire or cable between independent modules in a system such as a safety critical system. However, the present design is not limited to a fixed cable implementation, and may use a wireless over-the-air communications media. The wireless over-the-air communications may be realized using a radio, light wave (e.g. infrared) or other communications technique that does not require a physical connection. Examples of current wireless devices that may receive and transmit data include, but are not limited to, those devices meeting or complying with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 and Ericson Bluetooth specifications for short range radio technology, or an Infrared Data Association (IrDA) light wave technique.
While the present design may be used in various environments and applications, it will be discussed herein with a particular emphasis on a medical or hospital environment, where a surgeon or health care practitioner performs. For example, embodiments of the present design may include a phacoemulsification surgical system, vitrectomy system, or combined phaco-vitrectomy system comprising an independent graphical user interface (GUI) module, an instrument host module, and a controller module, such as a foot switch, to control the surgical system.
FIG. 1 illustrates a phacoemulsification system in block diagram to show the components and interfaces for a safety critical medical system in accordance with the present design. The particular embodiment illustrated in FIG. 1 contemplates that the GUT host 101 module and instrument host 102 module are connected by a serial communication cable 103 for the purposes of controlling the surgical instrument host 102 by the GUT host 101 . A foot pedal 104 switch module may transmit control signals relating internal physical and virtual switch position information as input to the instrument host 102 over serial communications cable 105 . The present design may employ the same novel ‘lightweight’ or bandwidth efficient communications protocol for GUI host to instrument host communications and instrument host to foot pedal switch communications.
The phacoemulsification system has a handpiece/needle 110 that includes a needle and electrical means, typically a piezoelectric crystal, for ultrasonically vibrating the needle. The instrument host 102 supplies power on line 111 to a phacoemulsification handpiece/needle 110 . An irrigation fluid source 112 is fluidly coupled to handpiece/needle 110 through line 113 . The irrigation fluid and ultrasonic power are applied by handpiece/needle 110 to a patient's eye, or affected area or region, indicated diagrammatically by block 114 . Alternatively, the irrigation source may be routed to the eye 114 through a separate pathway independent of the handpiece. The eye 114 is aspirated by the instrument host 102 peristaltic pump (not shown) through line/handpiece needle 115 and line 116 . A switch 117 disposed on the handpiece 110 may be utilized as a means for enabling a surgeon/operator to select an amplitude of electrical pulses to the handpiece via the instrument host and GUT host. Any suitable input means, such as, for example, a foot pedal 104 switch may be utilized in lieu of the switch 117 .
The system and method comprising the present design for managing communications between two independent modules within a safety critical medical system will be described. The present discussion is intended to provide a basic foundation for low overhead, reliable, bi-directional communications between two independent modules. For simplicity, the present design system and method will be described for the communications path between the GUT host module and the instrument host module that are part of a phacoemulsification machine, however the description may be applicable to any two modules in communication with one another comprising part of or the entire medical system. In this configuration, the control and feedback of the phacoemulsification machine may be accomplished by exchanging data between the GUI host and the instrument host. In this arrangement, the GUI host may provide the graphical user interface for controlling the instrument host, and the instrument host may provide control for the actual surgical devices connected to the instrument host.
In FIG. 1 , the GUI host 101 and instrument host 102 may be two separate independent software execution environments comprising the medical system applications software and the underlying operating systems. The present design may provide control and feedback of the medical system by exchanging data between the GUI host 102 and the instrument host, between software modules within the instrument host, between the instrument host and modules external to the instrument host 101 and/or GUI host 102 , or between software modules external to the instrument host 101 and/or GUT host 102 . The present design may realize this data exchange using a novel lightweight or bandwidth efficient communications protocol configured to support a master-slave protocol relationship. The communications protocol may be implemented in both the GUI host 102 and instrument host 101 and arranged to enable either module to act as the master and the other as the slave module. More than one software module may employ the protocol and aspects described herein.
General Aspects of the Protocol
The present design system and method communications protocol features data packets, message formats, and a communications watchdog. The present design may support two messaging formats when sending data packets via this lightweight protocol method, being either explicit or implicit format. The present design's explicit message format may contain a description of the data object contained in the message, for example a ServiceID and ClassID specified in the message header, wherein an implicit message may not contain a data object description.
The present design may enable data transmission in an explicit message between two modules in the form of data packets. The present design may construct packets that represent a collection of 8-bit bytes. The system may interpret each packet as a single item of data. Data packets transmitted may include the following bytes: a Start of Text (STX), a message ID (MsgID), a service ID (ServiceID), a class ID (ClassID), arbitrary length of data, Checksum (ChkSum), and ˜Checksum (˜ChkSum) as illustrated in FIG. 2A .
Each explicit request message transmitted by the master module, in accordance with the present design, may contain an STX 201 byte comprising an ACSII code with a value such as 0x02 in the first byte to indicate the start of a new message frame. The MsgID 202 may provide a description of the type of message the packet contains. The types of valid MsgID may include explicit requests, explicit acknowledge, explicit response, implicit request, and implicit response. The ServiceID 203 may provide a description of what the receiving entity (i.e. slave module) is to do with this message. The ServiceID provides the receiving module with the service to be performed on the request sent by the master module. The ServiceID byte is optional depending on the value of the MsgID. Some MsgID values do not require any ServiceID. In this situation, the present protocol may eliminate this byte from the packet. Appropriate values of the ServiceTD are dependent on the MsgID. The protocol may include the following ServiceID's: Get, Set, Start, Stop, and Shutdown. The ClassID 204 may provide a description of the data contained within the packet. The MsgID and ServiceID may define appropriate values for this byte. Not all MsgID and ServiceID combinations require a ClassID. In this situation, the protocol may eliminate this byte from the packet.
The ClassID, if present, may contain an identifier for one of up to 256 possible predefined data objects to indicate which object the attached data belongs, where the object may be sent by the master module and interpreted by the slave module. The data 205 transmitted may be of arbitrary length wherein the number of bytes is dependent upon the ClassID. If no ClassID is present, the data length is then dependent upon the MsgID and ServiceID combination. The objects data may be stored in the field represented by Data 0 to DataN. While data 205 and data 305 are shown as having multiple component bytes (Data 0 through DataN in certain instances) in FIGS. 2A , 2 B, 2 C, and 3 B, in reality data 205 and data 305 may potentially have a data length of zero bytes, as data bytes in general and data 205 and data 305 specifically are optional in these messages and in this design. The protocol may include a simple additive ChkSum 206 byte that stores the modulo-2 addition of all the bytes in the message, excluding its complement byte, itself, and the STX byte. Furthermore, ˜ChkSum 207 may store the 1's complement of ChkSum 206 . Although the protocol described herein is limited to 256 different MsgID's, ServiceID's, and ClassID's, it may be easily extended by using multiple bytes in each packet to encode these entities. Moreover, the protocol may be extended to include additional functionality. For example additional data objects, MsgID's, and ServiceID's may be defined to enable the communications protocol to handle file transfers and/or allow the data objects to be compressed.
Each explicit response message transmitted by the present design may contain an STX 201 byte, MsgID 202 byte, ClassID 204 byte, Data 205 byte(s), ChkSum 206 byte, and ˜Chksum 207 byte arranged in a similar manner as used in an explicit request message. For example, the instrument host, acting as the slave device, may respond to a Get service request message by returning the request data in the explicit response message format illustrated in FIG. 2B . Data fields Data 0 to DataN stores the objects data returned by the slave instrument host. In the situation where the GUI host, acting as the master device, sends a Set service request message, the slave instrument host may apply the data to the intended object and not return the objects data as with a Get service request. After responding with the requested data for the Get service request, the slave instrument host may send an acknowledgement message as illustrated in FIG. 2C to inform the master GUI host that the slave instrument host has completed processing the Get service request. The acknowledgment message sent by the slave instrument host indicates to the master GUI host that the slave has accepted the request it initiated The data 205 byte may contain either an indication of acknowledged or not acknowledge.
The present design may send data in an implicit message between two modules in the form of data packets. The present design master module may employ an implicit message request as illustrated in FIG. 3A to request that the slave module report its status on an on-going periodic basis. Following the implicit message request, the slave module may broadcast its status data to the master module on a timed basis. The frequency of broadcast may be defined when initiating the present design's lightweight protocol. In addition, the master module may modify the frequency of status being returned by the slave by sending an implicit message after the system initiates. In addition, the present design master module may employ implicit messaging to command the slave module to switch between different modes of operation or command the slave module to perform a set of specific operations as specified in the mode 303 byte. The implicit messaging method does not attach or convey data and ClassID as found in explicit messaging.
This implicit messaging method may include information in the message requesting the slave module to change modes of operation. In the situation where the master module desires to command the slave module to perform a set of specific operations, the method may employ a sub-mode 304 byte to send the desired command code. The sub-mode 304 byte may contain a code representing a request for sub-mode change or a code representing an operating command.
The slave module employing the present protocol may use an implicit response message as illustrated in FIG. 3B to report its status on an on-going periodic basis. The implicit response message may be time triggered enabling the slave module to respond without the master module periodically sending out requests for status. The present design may set the implicit response rate in multiples of hundreds of a millisecond and the data 305 is the field where the actual object resides.
Exchanging Message Packets
FIG. 4 illustrates exchanging message packets sent via the present designs lightweight protocol message formats. In this example, the GUI host 101 is deemed the master and the instrument host 102 becomes the slave subsystem or module. Acting as the master module, the GUI host 101 may use explicit messaging to send a request to the instrument host 102 to perform a service on the data object specified in the ClassID. The method may include five types of services associated with explicit messaging. The service to be performed may be specified within the ServiceID byte. Depending on the ServiceID, the instrument host 102 slave may respond with an explicit response, or the slave may take some action that does not require a response to be sent back to the initiating master GUI host. The method may specify a Get, Set, Stop, Start, or Shutdown service request.
For example, the master GUI host 101 may send an explicit message Get 401 service, or an explicit Get request, to request the slave instrument host 102 to send the data for the object specified in the ClassID. The slave instrument host 102 module may immediately respond to the request, and may send the requested data 402 to the master GUT host 101 . In addition, the slave may send an acknowledgement 403 message to indicate the slave instrument host has completed processing the Get request. The GUI host may send an explicit message Set 404 service request to the instrument host module to send data. The instrument host slave module copies the data sent within the Set request message to its internal object and may apply this data to the current operation. The slave module does not send data back to the master when processing Set service requests. The GUI host may send an explicit message Start 405 service request to the instrument host module to initiate and respond to all foot pedal 104 switch positions. The GUI host may send an explicit message Stop 406 service request to the instrument host module in order to suspend operations and enter into a predefined safe state (e.g. inflate eye, stop aspiration and vacuum while disabling cutting and/or other Phaco actions).
The GUI host may send an explicit message Shutdown 407 service request to the instrument host to command that it gracefully shutdown the system and terminate all running application processes. The slave responds with an acknowledgement message 403 for every request in accordance with the present design.
FIG. 5 illustrates an example of the present design's implicit messaging request and response mechanism. In this example, the GUI host may send an implicit GET request 501 message to command the instrument host to switch to a particular mode or sub-mode, or to perform a task as specified within the implicit request. The instrument host may respond to the implicit request with an acknowledgement 502 message to indicate the instrument host has completed the processing the request. In addition, the instrument host may periodically transmit implicit response data 503 messages back to the GUI host on a predefined time interval.
The present design may enable the master and slave modules to start up as two independent subsystems. After successful startup, each module may communicate a successful boot message to the other module. At this point, the master module may initiate the present design communications protocol by sending an explicit request message to start communications. Upon receipt of this request, the slave module may respond to the master by sending a protocol initiation acknowledgement.
Watchdog Function
The present design may enable a synchronous communications watchdog mechanism, also known as a safety critical communications watchdog or a medical event safety critical communications watchdog. The master module may send an explicit request message to the slave module to start a communications data object. This data object may define two bytes that affect the performance of the communication watchdog. A cyclic interval (CycInt) byte may define the interval, in milliseconds, at which both the master and slave test the communications watchdog. An expected packet rate (EPR) byte may define the initial message timer value. Both the master and slave modules contain a copy of the EPR byte. The present design may decrement the EPR byte value for each elapsed interval as defined by the CycInt byte. Each time a data packet is received from the other module, the EPR byte value is reset to the initial value. If a sufficient number of elapsed intervals are experienced by either module to cause the EPR byte value to be decremented to zero, the module may consider the communications watchdog to have failed and may take appropriate safety critical actions at this point.
For example, the master GUI host may send a Start service request message to the slave instrument host directing the slave to transition to an active state. In the active state, the slave instrument host may respond to foot pedal 104 switch commands and becomes operative in Phaco, Irrigation/Aspiration, Diathermy, Silicon Infusion/Extraction and Vitrectomy mode. In order for the GUI host to keep the instrument host in an active state, the master GUI host continues sending explicit messages before the EPR timer in the instrument host expires. If the EPR timer expires within the instrument host, the instrument host transitions to a safe state. For example, the instrument may transition from the active state to a state wherein the foot pedal is placed or returned to a position zero zone making the Phaco machine inoperative. In order to resume or return to an active state, the master GUI host reinitiates the communications protocol with the slave device.
In a preferred embodiment, as one of ordinary skill in the art will appreciate, the watchdog functionality can be implemented in the form of virtual device drivers known in the art, one residing on the master and one residing on the slave to enable the monitoring of the communications in both directions.
Error Detection and Correction
The present protocol may provide error detection and correction capabilities. For example, in order to ensure the instrument host subsystem operates with valid data at all times, the GUI host may use the explicit Get service request message to retrieve and verify the data sent to the instrument host. In the situation where the GUI host detects that the retrieved data is invalid, the GUI host may send the Stop command to the instrument host and cease transmitting messages. Upon receiving the Stop command, the instrument host may make a transition to the safe state In the event that the Stop command failed to arrive at the instrument host, the instrument host may enter the safe state when the EPR value expires since the GUI host has stopped transmitting messages. Alternatively, the GUI host may also periodically send messages to the instrument host to keep the instrument host in an operative mode and to correct the corrupted data with the information transmitted within subsequent messages.
Regarding checksums, the receiver of every packet recalculates the checksums and compares the checksums to the transmitted checksum values. If the checksums do not match, the packet is assumed invalid. Further, the use of explicit not acknowledge (NAK) packets as described herein may cause specific packets to be retransmitted.
The present communications protocol may alternatively be used between any two modules that are communicating via any asynchronous media. This communications protocol may be realized in either hardware or software. In addition, this communications protocol may be implemented inside another protocol, including but not limited to, Bluetooth and Transmission Control Protocol/Internet Protocol.
The design presented herein and the specific aspects illustrated are meant not to be limiting, but may include alternate components while still incorporating the teachings and benefits of the invention. While the invention has thus been described in connection with specific embodiments thereof, it will be understood that the invention is capable of further modifications. This application is intended to cover any variations, uses or adaptations of the invention following, in general, the principles of the invention, and including such departures from the present disclosure as come within known and customary practice within the art to which the invention pertains.
The foregoing description of specific embodiments reveals the general nature of the disclosure sufficiently that others can, by applying current knowledge, readily modify and/or adapt the system and method for various applications without departing from the general concept. Therefore, such adaptations and modifications are within the meaning and range of equivalents of the disclosed embodiments. The phraseology or terminology employed herein is for the purpose of description and not of limitation.
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A method and system of establishing communications between at least two independent software modules in a safety critical system, such as a medical system, is provided. The design comprises providing a media connection between software modules, wherein the software modules employ a communications protocol and participate in a bi-directional master-slave relationship between a master module and a slave module. The design further comprises sending an arbitrary length of data between the master and slave modules, wherein the arbitrary length of data is used by the master module to control and obtain status from the slave module, and sending arbitrary data further enables the slave module to return data and status information to the master module. The design also employs a safety critical communications watchdog between the master and slave modules, wherein the safety critical communications watchdog monitors communications quality between the master and slave modules. The protocol comprises bytes transmitted using a packet consisting of a start indication, a message identifier, an optional service identifier, a class identifier, an arbitrary length of data pertinent to the medical device comprising optional data, a checksum, and a checksum complement.
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CROSS REFERENCE TO RELATED APPLICATION
This application claims priority from U.S. Provisional Patent Application No. 60/843,145 filed Sep. 8, 2006 and U.S. Provisional Patent Application. No. 60/764,842 filed Feb. 3, 2006, which are incorporated by reference as if fully set forth.
FIELD OF INVENTION
The present invention is related to a wireless communication system including a transmitting node and a receiving node. More particularly, the present invention is related to a method for dynamically configuring a memory for hybrid automatic repeat request (H-ARQ) processes in a receiving node to permit a more flexible memory configuration and to improve the performance of H-ARQ processes.
BACKGROUND
Methods for improving data rates and the performance of wireless communication systems using H-ARQ processes are being investigated in the Third Generation Partnership Project (3GPP).
An H-ARQ scheme is used to generate transmissions and retransmissions with low latency. H-ARQ is a variation of an automatic repeat request (ARQ) error control method, which provides better performance than an ordinary ARQ method at the cost of increased implementation complexity. H-ARQ can be used in stop-and-wait retransmission or in selective repeat retransmission. Stop-and-wait retransmission is simpler to use. However, waiting for a receiver's acknowledgment of a signal reduces efficiency. Thus, multiple stop-and-wait H-ARQ processes are used in parallel to overcome the positive acknowledgement (ACK)/negative acknowledgement (NACK) round-trip delay due to this mechanism. Further, multiple H-ARQ processes allow high priority traffic to be sent immediately using a new H-ARQ process, rather than being stalled behind packets in transmission using an existing H-ARQ process. For example, when one H-ARQ process is waiting for an ACK, another H-ARQ process can be used to send more data.
In 3GPP, protocol messaging configures H-ARQ behavior, including H-ARQ memory availability. More specifically, the prior art permits protocol messages to configure an H-ARQ process with a buffer size and to exchange the buffer size with a communicating peer device, such as a WTRU or a Node-B. In the prior art, each H-ARQ process is configured with a particular H-ARQ memory limit. This configuration presents two limitations and inefficiencies. First, certain radio bearers may benefit from more H-ARQ processes, each with small memory requirements. Second, an application may benefit from fewer H-ARQ processes with larger buffer limits when the application has large memory requirements but can tolerate an increased number of H-ARQ retransmissions because the application does not have stringent delay requirements.
A challenge in implementing the H-ARQ mechanism is the receive memory requirement to buffer soft decoding decisions in the H-ARQ memory needed to implement incremental redundancy schemes.
Two of the desired improvements of long term evolution (LTE) of wideband code division multiple access (WCDMA) for universal mobile telecommunication systems (UMTS) are higher data rates as well as improved handling of different applications, particularly with different quality of service (QoS) requirements. LTE is also referred to as evolved universal terrestrial radio access (E-UTRA). To provide these desired improvements, LTE working groups are discussing flexible frame and transmission time interval (TTI) formats. Additionally, particular delay insensitive applications are able to tolerate a greater number of retransmissions.
As data rates increase, the amount of H-ARQ memory, (i.e. soft memory), needed for H-ARQ processes becomes a considerable cost factor for a baseband chipset. Therefore, H-ARQ memory optimizations are potentially a considerable design benefit. Unfortunately, the current H-ARQ memory allocation mechanism is too restrictive to handle these considerations. As a result, a new mechanism that permits for a more dynamic and flexible H-ARQ memory configuration is necessary.
SUMMARY
The present invention is related to a method for dynamically configuring a memory for hybrid automatic repeat request (H-ARQ) processes in a receiving node to permit a more flexible H-ARQ memory configuration and to improve the performance of H-ARQ processes. An H-ARQ memory in a receiving node is dynamically reserved for a plurality of H-ARQ processes. A transmitting node dynamically configures the H-ARQ memory in the receiving node for each new H-ARQ transmission. A receiving node signals a transmitting node during the establishment of an Radio Bearer utilizing H-ARQ transmission. The signaling informs a transmitting node of the capability to share an H-ARQ memory across a plurality of H-ARQ processes in a receiving node. The signaling informs a transmitting node of the capacity of an H-ARQ memory in a receiving node. An H-ARQ memory capacity is based on a maximum data rate and quality of service (QoS) requirement of a radio bearer. A transmitting node may dynamically configure the H-ARQ memory in a receiving node so that the memory requirement for a plurality of H-ARQ processes in aggregate exceeds the H-ARQ memory capacity of the receiving node. A transmitting node signals a receiving node instructing the receiving node to dynamically configure its H-ARQ memory accordingly.
If there is insufficient H-ARQ memory available at a receiving node to support H-ARQ transmission, only a subset of a plurality of H-ARQ processes may be activated at one time. When there is insufficient H-ARQ memory for processing a received H-ARQ transmission, a receiving node may signal a NACK, (with or without additional information indicating the insufficiency of the H-ARQ memory), an ACK, nothing, and/or information indicating the reason for the failed transmission may be transmitted to a transmitting node.
BRIEF DESCRIPTION OF THE DRAWINGS
A more detailed understanding of the invention may be had from the following description of a preferred embodiment, given by way of example and to be understood in conjunction with the accompanying drawings wherein:
FIG. 1 is a block diagram of a wireless communication system configured in accordance with the present invention;
FIG. 2 is a flow diagram of a dynamically configured H-ARQ memory allocation process implemented by the system of FIG. 1 ; and
FIG. 3 is a flow diagram of a dynamically configured H-ARQ memory configuration process implemented by the system of FIG. 1 when the aggregated memory requirement for a set of H-ARQ processes exceeds H-ARQ memory capacity at a receiving node.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereafter, the terminology “wireless transmit/receive unit (WTRU)” includes but is not limited to a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of user device capable of operating in a wireless environment. When referred to hereafter, the terminology “base station” includes but is not limited to a Node-B, a site controller, an access point (AP) or any other type of interfacing device capable of operating in a wireless environment.
The features of the present invention may be incorporated into an integrated circuit (IC) or be configured in a circuit comprising a multitude of interconnecting components.
FIG. 1 is a block diagram of a wireless communication system 100 configured in accordance with the present invention. The system 100 includes a receiving node 102 and a transmitting node 104 configured for H-ARQ transmissions. The receiving node 102 and the transmitting node 104 communicate via explicit signaling or implicit signaling using existing parameters. With respect to downlink H-ARQ transmissions, the receiving node 102 may be a WTRU and the transmitting node 104 may be a Node-B. With respect to uplink H-ARQ transmissions, the receiving node 102 may be a Node-B and the transmitting node may be a WTRU.
As shown in FIG. 1 , the receiving node 102 includes a processor 110 , an H-ARQ memory 114 , a receiver 116 , and a transmitter 118 . The processor 110 is configured to dynamically configure the allocation of H-ARQ memory 114 in accordance with signals received from the transmitting node 104 . The processor 110 is configured to control a plurality of receiving H-ARQ processes 112 .
In an alternative embodiment, the processor 110 may be configured to dynamically configure the allocation of the H-ARQ memory 114 without receiving any signals from the transmitting node 104 . The processor 110 determines a configuration of the H-ARQ memory 114 by itself and signals the determined H-ARQ memory 114 configuration to the transmitting node 104 via the transmitter 118 .
The H-ARQ memory 114 is reserved for a plurality receiving H-ARQ processes 112 . The H-ARQ memory 114 may be referred to as soft memory. Preferably, the H-ARQ memory 114 is dynamically shared across a plurality of H-ARQ processes 112 . The H-ARQ memory 114 is dynamically allocated among H-ARQ processes 112 . When the aggregated soft memory requirement for the plurality of H-ARQ processes 112 exceeds the capacity of the H-ARQ memory 114 , only certain subsets of the plurality of H-ARQ processes 112 may be active at any given time. Further, the amount of configured H-ARQ 114 memory may depend on a maximum data rate and/or QoS requirements of the radio bearer or MAC flow.
The receiver 116 of the receiving node 102 is configured to receive signals from the transmitting node 104 that instruct the receiving node 102 to configure its H-ARQ memory 114 accordingly. The transmitter 118 of the receiving node 102 is configured to signal an H-ARQ memory sharing capability and/or the capacity of the H-ARQ memory 114 to the transmitting node 104 . The H-ARQ memory sharing capability indicates whether the receiving node 102 can share its H-ARQ memory 114 across the H-ARQ processes 112 . The signaling may be explicit or implicit in accordance with existing parameters.
Still referring to FIG. 1 , the transmitting node 104 includes a processor 120 , an H-ARQ memory 124 , a receiver 126 , and a transmitter 128 . The processor 120 is configured to dynamically configure the H-ARQ memory 114 in the receiving node 102 . This memory configuration includes partitioning the H-ARQ memory across the plurality of H-ARQ processes 112 .
The processor 120 in the transmitting node 104 is configured to manage and configure the H-ARQ memory 114 in the receiving node 102 . During a transport format (TF) selection process, the processor 120 is configured to measure the H-ARQ memory 114 used by radio bearers, or MAC flows, being serviced in a current transmission time interval (TTI) when determining a transport block (TB) size and a modulation and coding scheme (MCS). The TF selection process may also consider the total data available to transmit, beyond the current TTI, and to reserve capacity in the H-ARQ memory 114 for subsequent TTIs to permit continuous, or almost continuous, transmission during the TTI for the currently selected TF transmission. The result is that the TB is sized to match the dynamically configurable H-ARQ memory 114 resources. Consequently, the dynamic configuration of the H-ARQ memory 114 in the receiving node 102 improves the performance of the H-ARQ processes 112 and the radio bearers and MAC flows mapped to the HARQ processes. The processor 120 is also configured to process a plurality of transmitting H-ARQ processes 122 .
The transmitter 128 of the transmitting node 104 is configured to signal an H-ARQ memory configuration command or recommendation to the receiving node 102 . As an example, with respect to downlink transmissions, the transmitter sends a command that the receiving node 102 must follow. As another example, with respect to uplink transmissions, the transmitter sends a recommendation that the receiving node 102 may follow. The transmitter 128 signals the receiving node 102 via explicit or implicit signaling using existing parameters. A transport format combination indicator (TFCI), a transport format resource indicator (TFRI), or other transmission associated signaling may be used to implicitly signal the H-ARQ memory requirement for each H-ARQ process to the receiving node 102 . Further, knowledge of an H-ARQ process identity (ID) may be used to implicitly identify the H-ARQ memory requirement for an H-ARQ process 112 . This information can be used to implicitly signal the H-ARQ memory 114 configuration to the receiving node 102 . Alternatively, the transmitter 128 may explicitly signal the amount of H-ARQ memory 124 in the transmitting node 104 that has been allocated to the receiving node 102 With these mechanisms HARQ process memory partitioning may be coordinated between the transmitter and receiver each TTI a new HARQ process transmission is initiated.
Another method of implicit identification of the HARQ memory requirement is when the scheduler identifies a specific TF or subset of allowed TF's that may be utilized by the transmitter. Then, the receiver HARQ memory 114 is partitioned based on the scheduling information.
FIG. 2 is a flow diagram of a dynamically configured H-ARQ memory allocation process 200 implemented by the system 100 of FIG. 1 . In step 202 , the receiving node 102 reserves an H-ARQ memory 114 for a plurality of H-ARQ processes 112 . In step 204 , the receiving node 102 signals an H-ARQ memory sharing capability and/or the capacity of the H-ARQ memory 114 to the transmitting node 104 . Note that step 204 may only be needed when the receiver is a WTRU. The signaling indicates to the transmitting node 104 whether the receiving node 102 is capable of sharing the H-ARQ memory 114 across the plurality of H-ARQ processes 112 . The signaling may also indicate the capacity of the H-ARQ memory 114 in the receiving node 102 . The signaling may be explicit or implicit in accordance with existing parameters.
In step 206 , the transmitting node 104 dynamically configures (partitions) the H-ARQ memory 114 in the receiving node 102 for H-ARQ processes 112 to improve the performance of H-ARQ processes 112 . In step 208 , the transmitting node 104 signals an H-ARQ memory configuration command or recommendation potentially in each new HARQ transmission to the receiving node 102 . The signaling for partitioning of HARQ memory may be explicit or implicit. Preferably, the transmitting node uses fast physical layer signaling to configure and reconfigure the soft memory partitions between the H-ARQ processes 112 in the H-ARQ memory 114 . The transmitting node 104 may also use Layer 2 MAC or Layer 3 radio resource control (RRC) signaling to configure and reconfigure the soft memory partitions between the H-ARQ processes 112 in the H-ARQ memory 114 . As an optional embodiment, the association of H-ARQ processes 112 with specific radio bearers may be reconfigured through MAC or RRC signaling. The signaling is invoked upon establishment, release, or reconfiguration of the radio bearers. Consequently, the H-ARQ memory 114 in the receiving node 102 is dynamically configured to permit the improved performance of H-ARQ processes 112 at any potential time a new HARQ process transmission is initiated. It should be noted that after steps 202 and 204 , steps 206 and 208 may repeat each TTI a new HARQ process transmission is initiated.
FIG. 3 is a flow diagram of a dynamically configured H-ARQ memory allocation process 300 implemented by the system 100 of FIG. 1 when the aggregated H-ARQ memory requirement for a set of H-ARQ processes 112 exceeds the H-ARQ memory 114 at the receiving node 102 .
In step 302 , the receiving node 102 reserves an H-ARQ memory 114 for a plurality of H-ARQ processes 112 . The H-ARQ memory 114 capacity may be changed by the receiving node 102 . In step 304 , the receiving node 102 signals an H-ARQ memory sharing capability and/or the capacity of the H-ARQ memory 114 to the transmitting node 104 . The signaling indicates to the transmitting node 104 whether the receiving node 102 is capable of sharing the H-ARQ memory 114 across the plurality of H-ARQ processes 112 . The signaling may also indicate the capacity of the H-ARQ memory 114 in the receiving node 102 . The signaling may be explicit or implicit in accordance with existing parameters.
In step 306 , the transmitting node 104 dynamically configures the H-ARQ memory 114 in the receiving node 102 so that the aggregated memory requirement for the plurality of H-ARQ processes 112 exceeds the capacity of the H-ARQ memory 114 . In step 308 , the transmitting node 104 signals an H-ARQ memory configuration command or recommendation potentially in each new HARQ transmission to the receiving node 102 .
In step 310 , the receiving node 102 determines whether there is sufficient H-ARQ memory 114 available to support an H-ARQ transmission. If there is insufficient H-ARQ memory 114 to support an H-ARQ transmission and support soft combining, one of the following three options 312 , 314 , and 316 may be implemented for an failed H-ARQ transmissions.
In step 312 (option 1 ), the receiving node 102 signals a NACK to the transmitting node 104 . The NACK informs the transmitting node 104 that the H-ARQ transmission has not been received correctly.
In step 314 (option 2 ), the receiving node 102 signals an ACK to the transmitting node 104 . The ACK falsely indicates that the receiving node 102 has received an H-ARQ transmission when the receive node 102 does not want the transmit node 104 to retransmit the H-ARQ transmission. This procedure exists to prevent H-ARQ retransmission when there is insufficient H-ARQ memory 114 available. This scenario assumes that it is not possible for the receiving node 102 to inform the transmit node 104 that no H-ARQ memory 114 is available. This is beneficial in H-ARQ schemes where H-ARQ retransmissions are not self-decodable. If a separate ARQ scheme exists to correct residual H-ARQ transmission errors, the ARQ scheme could recover the transmission.
In step 316 (option 3 ), the receiving node 102 waits for sufficient H-ARQ memory 114 to become available to support an H-ARQ transmission. The receiver node 102 signals nothing back to the transmitting node 104 .
In an alternative embodiment, the receiving node 102 may signal additional information indicating the reason for the failure to support the H-ARQ transmission. For example, the failure was due to a shortage of H-ARQ memory 114 . This additional information may be signaled along with the ACK/NACK signaling described above. Further, the additional information may be signaled in place of the ACK/NACK signaling.
As an informative example, suppose that an H-ARQ memory 114 in a receiving node 102 has a one (1) Mb capacity and supports four identically configured H-ARQ processes. This process 300 permits a fifth H-ARQ process to be instantiated so that the H-ARQ memory 114 is not guaranteed to be sufficient for the H-ARQ processes 112 . The H-ARQ memory 114 may contain soft memory partitions that are preconfigured to support multiple H-ARQ processes 112 . The dynamic configuration of H-ARQ processes 112 may ensure that the H-ARQ memory 114 capacity is not exceeded.
The features of the present invention may be incorporated into an integrated circuit (IC) or be configured in a circuit comprising a multitude of interconnecting components.
Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention. The methods or flow charts provided in the present invention may be implemented in a computer program, software, or firmware tangibly embodied in a computer-readable storage medium for execution by a general purpose computer or a processor. Examples of computer-readable storage mediums include a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs).
Suitable processors include, by way of example, a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and/or a state machine.
A processor in association with software may be used to implement a radio frequency transceiver for use in a wireless transmit receive unit (WTRU), user equipment (UE), terminal, base station, radio network controller (RNC), or any host computer. The WTRU may be used in conjunction with modules, implemented in hardware and/or software, such as a camera, a video camera module, a videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, a Bluetooth® module, a frequency modulated (FM) radio unit, a liquid crystal display (LCD) display unit, an organic light-emitting diode (OLED) display unit, a digital music player, a media player, a video game player module, an Internet browser, and/or any wireless local area network (WLAN) module.
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A method and apparatus for dynamically configuring a memory for hybrid automatic repeat request (H-ARQ) processes in a receiving node to permit a more flexible H-ARQ memory configuration and improve the performance of H-ARQ processes. An H-ARQ memory in the receiving node is reserved for a plurality of H-ARQ processes. A transmitting node dynamically configures the H-ARQ memory in the receiving node for each H-ARQ transmission so that the memory requirement for a plurality of H-ARQ processes exceeds the H-ARQ memory capacity. If there is insufficient H-ARQ memory available to support H-ARQ transmissions, only a subset of the plurality of H-ARQ processes may be activated at a time. When there is insufficient H-ARQ memory for processing H-ARQ transmissions, a negative acknowledgement (NACK), an acknowledgement (ACK), nothing, and/or information indicating the reason for a failed transmission may be transmitted to a transmitting node.
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This is a divisional of application Ser. No. 08/498,347 filed Jul. 5, 1995, now U.S. Pat. No. 5,562,775.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a plasma downstream processing apparatus and a plasma downstream processing method, and more particularly to a plasma downstream processing apparatus and a plasma downstream processing method adapted for ashing an organic resist or for isotropic etching process used in manufacture of a semiconductor device, and having a high processing speed and giving less damage to the object to be processed.
2. Description of the Related Art
Recently, such a plasma downstream processing technique which can perform the processing at a high precision and give less damage to the substrate to be processed is increasingly demanded along with the high integration of a semiconductor integrated circuit device.
More specifically, high processing speed and less damage in the object to be processed is demanded in an ashing process for an organic resist and in an etching process for an insulating film. Plasma downstream processing would be promising in this regard.
FIG. 4 shows a conventional shower head type ashing apparatus. An ashing apparatus 50 comprises an aluminum housing 51 which defines an inner space. A microwave transmitting window 52 made of quartz is disposed in the housing 51 and hermetically couples to the inner surface of the housing, to define a microwave introduction chamber 61 thereabove. A waveguide 54 for transmitting microwave is connected to the microwave introduction chamber 61 and supplies microwave thereto.
The housing 51 and the microwave transmitting window 52 define an evacuatable hermetic space below the microwave transmitting window 52. A shower head 55 is disposed parallel to the microwave transmitting window 52 and coupled to the inner wall of the housing 51. A plasma generating chamber 64 is defined between the microwave transmitting window 52 and the shower head 55. A gas supply tube 53 is connected to the plasma generating chamber 64. A downstream processing chamber 68 is defined in the housing 51 below the shower head 55. The downstream processing chamber 68 contains a susceptor 60 which is provided with a heater 61.
Most of the constituent parts of the ashing apparatus 50, except the microwave transmitting window 52 and sealing members, are formed of aluminum. A substrate 59 to be processed, such as silicon wafer having an organic resist film thereon is mounted on the susceptor 60.
An O 2 containing gas is introduced from the gas introducing tube 53 to the plasma generating chamber 64 and microwave is introduced from the waveguide 54 through the microwave introduction chamber 61 to the plasma generating chamber 64, to generate plasma of the O 2 containing gas.
By the action of the plasma, oxygen radicals, which are the neutral and reactive species, together with electrons and ions are generated. These oxygen radicals are to be introduced into the processing chamber 68 through the shower head 55. The introduced oxygen radicals are transported downward and irradiated onto the surface of the substrate 59 mounted on the susceptor 60. The organic resist film coated on the substrate 59 is ashed by the irradiated oxygen radicals.
The shower head 55 is formed of a metal plate having a multiplicity of through holes, and is usually called a punching metal. Each through hole has a diameter of about 1 mm and a length (thickness) of the order of 2-3 mm. The O 2 containing gas cannot go above the microwave transmitting window 52. The microwave cannot enter below the shower head 55. Since the through holes in the shower head 55 is small in diameter, plasma generated in the plasma generating chamber 64 is confined in the chamber 64 and cannot enter the processing chamber 68. Charged particles such as electrons and ions also confined in the plasma generating chamber.
Except the microwave transmitting window 52, most of the plasma generating chamber and the processing chamber are formed of aluminum which is a metal capable of shielding microwave and generating no contamination. During the ashing treatment, the inner wall of the ashing chamber 68 becomes 200°-300° C. due to the influence of the plasma in the plasma generating chamber 64, and the shower head 55 becomes hotter,
When the temperature of the metal inner surfaces of the respective chambers becomes hot, the possibility of annihilating oxygen radicals by the collision with the inner wall increases. Therefore, the radical concentration decreases and the ashing rate decreases. The decrease in the ashing rate also means a variation in the ashing rate and accompanies a decrease in the controlling accuracy.
SUMMARY OF THE INVENTION
An object of this invention is to provide a plasma downstream processing apparatus which can afford a high processing speed, less variations in the processing speed, and less damage to the object to be processed.
Another object of this invention is to provide a plasma downstream processing method which gives less damage to the object to be processed, and a high processing speed.
According to an aspect of this invention, there is provided an apparatus for performing plasma downstream processing comprising: a microwave introduction chamber defined by a wall having a microwave transmitting window formed of a microwave transmissive material at a part thereof; a plasma generating chamber facing to said microwave introduction chamber through said microwave transmitting window and having a conductive microwave shield disposed generally parallel to said microwave transmitting window, to define a plasma generating space, said microwave shield including a central member which is formed of a continuous conductor and an outer member disposed outside the central member through a gap which has a folded cross sectional shape in a plane including a central normal to the microwave transmitting window; and an evacuatable processing chamber disposed adjacent to said plasma generating chamber through said microwave shield.
Part of the inner surface of the plasma generating chamber, particularly at the area where the plasma density is high maybe coated with quartz.
According to another aspect of this invention, there is provided a method of performing plasma downstream processing, comprising the steps of: generating plasma of an oxygen-containing gas with a microwave, in a space having a thickness of 1/10 or less of a wavelength λ of the microwave; deriving the gas from opening formed around the central portion of said plasma through a gap, which gap has a loop-shaped cross section in a plane parallel to said space, and a folded cross section in a plane including a central normal to said space; irradiating the derived gas to an object to be processed.
It has been experimentally found that the use of a microwave shield having a gap comprising a cylindrical part and a folded part can effectively transmit radicals and prevent passage of charged particles.
A portion of plasma in the plasma generating chamber, that is the portion where the microwave electric field is high, is shielded by a continuous central conductive member. Thus, the plasma can be effectively confined in the plasma generating chamber. Also, the cylindrical gap can have a sufficiently wide width to enhance the transportation efficiency of radicals. Therefore, the processing speed can be enhanced without giving damages to the substrate to be processed.
By coating the inner surface of the plasma generating chamber with a quartz layer at least partially, the annihilation of oxygen radicals can be reduced even when the temperature of the inner wall is raised, and variation or decrease of the processing speed can be decreased. It is particularly effective when the processing uses no fluorine containing gas. Effective ashing of an organic resist is realized by using one of ashing gases O 2 , O 2 +H 2 O, and O 2 +N 2 , and by coating the inner surface of the plasma generating chamber with a quartz layer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A to 1F show an ashing apparatus according to the first embodiment of this invention, using no quartz cover, wherein FIGS. 1A to 1C, 1E and 1F are cross sectional views and FIG. 1D is a schematic perspective view.
FIGS. 2A to 2C are cross sectional views showing variations of the first embodiment.
FIGS.3A and 3B are cross sectional views showing an ashing apparatus according to the second embodiment of this invention, with quartz covers. FIG. 4 is a cross sectional view of an ashing apparatus of shower head type without quartz cover according to the conventional art.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1A to 1F show an ashing apparatus according to an embodiment of this invention. FIG. 1A is a longitudinal cross section. An ashing apparatus comprises a microwave introduction chamber 1 for introducing microwave from a waveguide 22, a plasma generating chamber 4 for generating plasma of a gas introduced from a gas supply tube 3, a microwave transmitting window 2 made of quartz for hermetically separating the plasma generating chamber 4 from the microwave introduction chamber 1, an ashing chamber 8 containing a susceptor 10 with a heater 11 for carrying a substrate 9 to be processed, and a microwave shield 5 and 6 for separating the ashing chamber 8 from plasma generating chamber 4, shielding the microwave and charged particles, and allowing passage of neutral particles.
As shown in FIG. 1F, a housing 21 defines an evacuatable hermetic space, with the microwave transmitting window 2 and hermetic seal 23 as shown in FIG. 1A, including the plasma generating chamber 4 and the ashing chamber 8. An evacuation system P is connected to the housing 21 at a bottom portion. The microwave shield 5 and 6 includes an outer annular member 5 and an inner cylindrical member 6, which are made of good electric conductor, i.e. metal such as aluminum, and disposed concentrically. An outer annular member 5 has a cylindrical aperture 25 at a central part, and is fixed in close contact to the housing 21 at a peripheral portion thereof with a plurality of screws. The upper surface of the outer annular member 5 at the peripheral portion is stepped to be thin. The inner cylindrical member 6 includes a cylindrical part 6a and a disc-shaped brim 6b extending outwards from a bottom portion of the cylindrical part 6a. The brim 6b is fixed to the outer annular member 5 through spacers 27 with a plurality of screws.
FIG. 1D is a schematic view illustrating decomposed microwave transmitting window 2, outer annular member 5, spacers 27, and an inner cylindrical member 6.
The structure of the microwave shield 5 and 6 will be describe in more detail. FIG. 1B shows a cross section along line IB--IB shown in FIG. 1A. The central portion is occupied by a cylindrical part 6a of the inner cylindrical member 6 and the outer annular member is disposed outside of the cylindrical part 6a through a cylindrical gap 7a.
As shown in FIG. 1B, the outer circumference 26 of the cylindrical part 6a has a smaller diameter than that of the cylindrical opening 25 of the outer annular member 5, to form a cylindrical gap 7a therebetween.
As shown in FIG. 1A, the bottom surface of the outer annular member 5 and the upper surface of the disc-shaped part 6b of the inner cylindrical member 6 are separated by spacers 27 with a width w2, to form a disc-shaped gap 7b. The inner circumference of the disc-shaped gap 7b is connected to the bottom end of the cylindrical gap 7a, jointly defining a gap (gas pass age) 7 of a L-shaped cross section.
As shown in FIG. 1C, a cylindrical gap 7a of a width w1 and a height d1 is formed between the outer circumferential surface 26 of the cylindrical part 6a of the inner cylindrical member 6 and the aperture 25 of the outer annular member 5. A disc-shaped gap 7b of a height w2 and the width d2 is formed between the brim 6b and the bottom surface of the outer annular member 5. It will be apparent that any particles cannot pass through the folded gap 7 without making collision with the gap wall. Further detailed criteria of the gap 7 will be described later.
As shown in FIG. 1A, the plasma generating chamber 4 includes a disc-shaped portion 4a of a height h and ring-shaped portion 4b having a larger height defined by the microwave transmitting window 2 and the stepped surface of the outer annular member 5 at the outer circumference of the disc-shaped portion 4a.
As shown in FIG. 1E, a plurality of gas supply pipes 3 are connected to the ring-shaped portion 4b of the plasma generating chamber 4. As shown in the figure, each two gas passages 3 are connected at the opposing positions of the plasma generating chamber 4. For example, gas A is O 2 , and gas B is H 2 0. Each gas is supplied from a pair of opposing gas passages 3. When one species of gas is used, it is preferable to supply the gas at least from the opposing two positions. The gas supplied from the gas passages 3 are uniformed supplied to the disc-shaped portion 4a through the ring-shaped portion 4b.
A cylindrical gap 7a has a circular opening outside of a central portion 13 of the disc-shaped portion 4a. When O 2 gas is introduced from the gas passages 3 into the plasma generating chamber 4 at a desired pressure, and microwave is applied thereto, plasma is generated in a region near the window 2 confined by the shield 5 and 6 and radiates plasma emissions. In the plasma, electrons, ions, and radicals are generated. The oxygen radicals generated in the plasma are supplied to the ashing chamber 8 through the cylindrical gap 7a and the disc-shaped gap 7b.
It is preferable that the continuous cylindrical part 6a of the inner cylindrical member 6 shields the plasma in the plasma generating chamber 4. In the plasma, charged particles (ions and electrons) of high energy are generated at high density. Those charged particles directed downward from the plasma are shielded by the central cylindrical part 6a.
When the distance between the microwave transmitting window 2; and the microwave shield 5 and 6 becomes long, it has been experimentally found that the matching of the microwave becomes difficult. When the distance becomes long, reflection wave tends to occur. For example, when a microwave of 2.45 GHz is used, reflection occurs at the distance above about 1/10 of the microwave wavelength λ to be used, i.e. above λ/10, to render the matching difficult. For making the matching of the microwave easy, the distance between the window 2 and the shield 5 and 6 is preferably at about λ/10 or below.
When the distance is made short, matching can be easily taken but the capacity for supplying neutral active species is lowered. Then, the ashing rate becomes low. It is preferable to select the distance considering the required ashing rate.
For obtaining a high ashing rate, while preventing reaching of charged particles on the wafer, it seems effective to set the disk-shaped gap 7b to thinner and longer, than the cylindrical gap 7a. Charged particles seem to reach the bottom of the cylindrical gap. The height or width w2 of the disk-shaped gap is preferably selected to annihilate the charged particles sufficiently.
In an example using microwave of 2.45 GHz, the diameter of the plasma generating chamber 4 is 110 mm, the width of the ring-shaped portion 4b of the plasma generating chamber is 20 mm, leaving the central disc-shaped portion 4a with a diameter of 70 mm, the height h of the disc-shaped portion 4a of the plasma generating chamber 4 is 1/10 of the wavelength of the microwave (about 120 mm), λ/10≃12 mm, the width w1 if the cylindrical gap 7a is 1/6 of λ (20 mm), width w2 of the disc-shaped gap 7b is 2 mm, the height (or length) d1 of the cylindrical gap 7a is 14.5 mm, and the width (or length) d2 of the brim 4b is 26 mm.
In performing ashing using this example ashing apparatus, work gas, such as O 2 gas, is introduced from the gas supply pipes 3 into the plasma generating chamber 4, and microwave of 2.45 GHz is applied to generate plasma of O 2 gas, etc to generate oxygen radicals. These oxygen radicals are introduced into the ashing chamber 8 through the gap 7, and irradiated onto the resist film coated on the surface of the substrate 9 to be processed and mounted on the susceptor 10. The resist film is ashed by the oxygen radicals.
Comparison of the above-described ashing apparatus with the conventional apparatus shown in FIG. 4 was made by using gases of O 2 +H 2 O, O 2 +N 2 , and O 2 +CF 4 . First, description will be made on the case of using O 2 +H 2 O. The process conditions include:
O 2 flow rate: 1350 sccm,
H 2 O flow rate: 150 sccm,
pressure: 1 Torr,
microwave power: 1.5 kW, and
substrate temperature: 180° C.
The ashing rate in the example apparatus according to the embodiment was 2.6 μm/min., and that of the conventional apparatus of FIG. 4 was 1.0 μm/min. The ashing rate of the example apparatus was above twice the rate of the conventional apparatus.
In the above example, the cylindrical gap 7a formed between the microwave shield members 5 and 6 was set to 20 mm, which is about λ/6 relative to the microwave wavelength λ. For confirming whether charged particles reach the substrate 9 in the ashing treatment or not, the temperature of the substrate was changed to obtain activation energy, using O 2 gas as the work gas. The obtained activation energy was 0.5 eV. This value coincides with the known value as the activation energy of chemical reaction between oxygen radicals and organic materials (c.f. J. Electrochem. Soc. 130, 2459 (1983)).
When other species than oxygen radicals, e.g. ions and electrons, are incorporated in the reaction, the activation energy will becomes smaller than 0.5 eV, such as 0.4 eV, and 0.3 eV. Thus, it was confirmed that the ashing in the above-described ashing apparatus was damage free, wherein charged particles did not reach the substrate 9.
When with of the gap 7a was increased to 30 mm (≃λ/4), the activation energy became about 0.4 eV, indicating that charged particles reached the substrate 9. In this case, if the diameter of the brim 6b of the inner cylindrical member 6 was increased, charged particles could be prevented from reaching the substrate 9, but the ashing rate would be lowered.
Therefore, for performing damage free processing while maintaining a certain level of ashing rate, the cylindrical gap 7a formed in the microwave shield 5 and 6 is preferably set about λ/5 or less, where λ indicates the wavelength of the microwave to be used.
In the case of using O 2 +N 2 as the wording gas, the processing conditions were set as follows.:
O 2 flow rate: 1350 sccm,
N 2 flow rate; 150 sccm,
pressure: 1 Torr,
microwave power: 1.50 kW, and
substrate temperature: 180° C.
The ashing rate of the above-described example apparatus was 1.2 μm/min while that of the conventional apparatus of FIG. 4 was 0.5 μm/min. The ashing rate of the example apparatus was more than twice the rate of the conventional apparatus.
In the case of using O 2 +CF 4 as the working gas, the processing conditions were set as follows:
O 2 flow rate: 900 sccm,
CF 4 flow rate: 100 sccm,
pressure: 1 Torr,
microwave power: 1.5 kW, and
substrate temperature: 40° C.
The microwave transmitting window 2 is formed of a ceramic resistant to fluorine.
The ashing rate of the example apparatus was 4.0 μm/min, while that of the conventional apparatus of FIG. 4 was 2.5 μm/min. The ashing rate of the example apparatus was about 1.75 times as large as that of the conventional apparatus.
In the respective cases, it was found that the ashing rate of the example ashing apparatus was higher than that of the conventional one and still it was possible to perform damage free ashing.
Next, etching of SiO 2 using the apparatus as described above will be explained. A mixed gas of O 2 +CF 4 was used as the working gas, and the process conditions were:
μwave transmitting window; ceramic
O 2 flow rate; 100 sccm,
CF 4 flow rate: 400 sccm,
pressure: 1 Torr,
microwave power: 1.5 kW, and
substrate temperature: 150° C.
The etching rate of SiO 2 in the example apparatus was 230 nm/min, while that of the conventional apparatus of FIG. 4 was 150 nm/min. The etching rate of the example apparatus was about 1.5 times as large as that of the conventional one.
FIGS. 2A to 2C show variations of the ashing apparatus illustrated in FIGS. 1A to 1F.
FIG. 2A shows a structure wherein an outer annular member 5 and inner cylindrical member 6 having a same height are concentrically disposed, arid a brim 15 is extended from the bottom of the outer annular member 5 toward inside below the inner cylindrical members 6. The brim 15 make a close contact with the outer annular member 5 and couples to the inner cylindrical member 6 through spacers 27. The outer annular member 5 and the inner cylindrical member 6 forms a cylindrical gap 7a therebetween. The inner cylindrical member 6 and the brim 15 form a disc-shaped gap 7b therebetween. The gaps 7a and 7b form a gas passage having an L-shaped cross section. The outlet of the gas passage is directed toward the center of the chamber.
FIG. 2B shows a structure wherein an outer annular member 5 and an inner cylindrical member 6 having a same height are concentrically disposed, and an annular brim 15 is disposed therebelow with a gap therebetween. The brim 15 is coupled to the outer annular member 5 and the inner cylindrical member 6 through spacers 27, forming annular disc-shaped gap 7b with an inner and an outer outlets, therebetween. The lower end of the cylindrical gap 7a is connected to approximately center of the annular disc-shaped gap 7b to form a gas passages of an inverted T-shaped, or upside-down T-shaped cross section.
FIG. 2C shows a structure wherein, in addition to the structure of FIG. 2B, another gas passage is formed through the inner cylindrical member 6. An inner cylindrical member 6 is divided into a central cylindrical member 6A and an outer cylindrical member 6B, to form a cylindrical gap 7c therebetween. Below the central cylindrical member 6A and the outer cylindrical member 6B, an annular disc-shaped brim 16 is disposed with a gap therefrom, to form an annular disc-shaped gap 7d. The gaps 7c and 7d form gas passages of an inverted T-shaped cross section. In this case, two cylindrical gas passages are formed.
The number of gas passages, and the cross sectional shapes of the gas passages are not limited to the above. Various gas passages can be made using cylindrical gas passage and an annular or disc-shaped gas passage which is directed almost orthogonal to the axis of the cylindrical gas passage. Also, looped gaps of various shape other than circular gap, such as ellipsoidal gap, can be employed.
FIGS. 3A and 3B illustrate an ashing apparatus according to another embodiment of this invention. Similar to the foregoing embodiment, the ashing apparatus comprises, a microwave introduction chamber 1 for introducing microwave and transmitting microwave through a microwave transmitting window 2, a plasma generating chamber 4 for generating plasma of a gas introduced from gas supply pipes 3, the microwave transmitting window 2 separating the microwave introduction chamber 1 and the plasma generating chamber 4, an ashing chamber 8 containing a susceptor 10 for mounting a substrate 9 to be processed, and microwave shield 5 and 6 for separating the ashing chamber 8 and the plasma generating chamber 4, shielding the microwave and charged particles, and allowing passage of neutral particles such as neutral reactive species (radicals).
Here, the surface of the microwave shield 5 and 6 exposed to the plasma is covered with quartz layers 12. Further, the surface of microwave shield 5, 6 exposed to the gap 7 is also coated with quartz layers 12. The whole bottom surface of the outer annular member 5 is also covered with the quartz layers 12.
Although FIGS. 3A and 3B show that the surfaces of the microwave shield 5 and 6 exposed in the plasma generating chamber 4 are covered with quartz layers 12, smaller but similar effects can be obtained by coating part of the exposed surfaces of the microwave shield 5 and 6, for example, by shielding the central portion of the upper surface.
When a fluorine-containing gas is used as the work gas, the quartz layer may be etched. Thus, this structure is particularly useful when the work gas contain no fluorine. The quartz layer serves to reduce the annihilation rate of oxygen radicals at the surface. It may be as thin as several tens microns. When the quartz layer is thin enough, the design of the microwave shield 5, 6 may be almost the same as that of the foregoing embodiment. It is preferable to select the height between the microwave transmitting window 2 and the central cylindrical member 6a of the microwave shield to be at λ/10 of the microwave wavelength λ or less for making the matching of the microwave easy. Also, it is preferable to select the cylindrical gap 7a to be λ/5 or smaller for preventing charged particles to reach the substrate 9. For example, the height of microwave generating chamber 4 in a central portion is set at 12 mm and the cylindrical gap 7a is set at 20 mm. The quartz layer can be manufactured separately or can be sputtered on the aluminum parts.
In an example, the thickness of the quartz layer is set at 2mm. When the quartz layer is thick, the microwave transmitting character of the quartz can be considered.
Ashing characteristics of the ashing apparatus shown in FIGS. 3A and 3B were measured in the above-mentioned example structure using O 2 +H 2 O and O 2 +N 2 as working gases.
In the case of using O 2+H 2 O as the wording gas, process conditions were set as follows:
O 2 flow rate: 1350 sccm,
H 2 O flow rate : 150 sccm,
pressure: 1 ; Torr,
microwave power: 1.5 kW, and
substrate temperature: 180° C.
The ashing rate of the example apparatus according to this embodiment was 3.5 μm/min, while that of the example apparatus of the foregoing embodiment was 2.6 μm/min, indicating that the present embodiment can exhibit a higher ashing rate.
In the case of using O 2 +N 2 as the working gas, the process conditions were set as follows:
O 2 flow rate: 1350 sccm,
N 2 flow rate: 150 sccm,
pressure: 1 Torr,
microwave power: 1.5 kW, and
substrate temperature: 180° C.
The ashing rate of the example of this embodiment was 1.6 μm/min, while that of the apparatus of the foregoing embodiment was 1.2 μm/min, indicating that the present embodiment can exhibit a higher ashing rate.
The ashing apparatus of this embodiment with quartz covers 12 is superior to the foregoing embodiment in the point that the annihilation of oxygen radicals at the surface is suppressed by the existence of quartz layer on the surface of the microwave shield 5 and 6. Thus, a higher ashing rate can be obtained in this embodiment, even compared to the first embodiment described earlier.
In the above embodiments, the central portion of the plasma generating chamber 4 coincides with the portion where the electric field of the standing microwave has larger amplitude and plasma density becomes highest. When other shapes than circular shape are employed as the horizontal cross sectional shape of the plasma generating chamber, the central area of high plasma density can be changed accordingly.
A loop-shaped gap surrounding the area of high plasma density can be employed in place of the above-described annular or circular gap. Although aluminum is used as the material for constituting the mechanical components of the microwave shield, plasma generating chamber, and the processing chamber, other metals or conducting materials can also be used. A microwave transmitting window can also be made of ceramics as well as quartz.
The ashing apparatus as described above can be combined with another etching apparatus for etching an aluminum wiring layer, for example, by using an etching gas Cl 2 +BCl 2 +SiCl 4 . In such a case, an evacuatable transport chamber can be coupled to these apparatuses to realize a system in which substrates can be transferred from one apparatus to another without exposing them to external atmosphere.
Although description has been made referring to the preferred embodiments of this invention, the invention is not limited thereto. For example, various changes, substitutions, alterations, improvements, or combinations can be made within the scope of the appended claims.
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A method for performing plasma downstream processing by generating plasma of an oxygen-containing gas with a microwave in a space having a thickness of 1/10, or less, of a wavelength λ of the microwave, deriving the generated plasma of the oxygen containing gas from such space through an opening formed around the central portion of such plasma generating space through a gap having a loop-shaped cross section in a plane parallel to the space and folded cross section in a plane including a central portion normal to such space; and irradiating the generated plasma of the oxygen containing gas derived from the plasma generating space to an object to be processed.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the control of a vehicle stopped on a hill, particularly to holding the vehicle against unintended rolling.
2. Description of the Prior Art
In micro hybrid vehicles where engine is shut down when the vehicle is stopped it is desirable to prevent the vehicle from rolling backwards when vehicle is on an uphill grade. This is particularly critical when the brake pedal is released but the engine is in the process of starting up and has not developed full torque.
At the same time when the vehicle is stopped on a downhill slope it is not necessary to inhibit vehicle motion since it is common driver expectation to see vehicle rolling on the downgrade road when brakes are released.
In some existing art this is accomplished through a hill hold system in which the wheel brakes are applied. These systems require grade detection, which can be challenging due to various electronic noise factors such as temperature and time drift of the grade sensor signal, and various failure modes when the sensor information is not available to the brake system.
Some brake hill hold systems also require an electric pump to create either hydraulic pressure or vacuum, which maintain excessive brake pressure once the brake pedal is released. This pump depletes the vehicle battery and thus reduces potential fuel economy benefit.
SUMMARY OF THE INVENTION
A method for controlling a vehicle on an uphill incline includes automatically shifting a transmission to first gear, automatically stopping the engine, using wheel torque to maintain a one-way clutch engaged and to hold a transmission component against rotation, preventing vehicle rollback by automatically engaging a target gear and tying-up the transmission automatically while restarting the engine, and automatically reengaging first gear.
No brake intervention is required to maintain hill hold eliminating potential need for the brake vacuum supply or for the electric brake pump.
Also no grade sensor, such as a tilt detection sensor, is required for the execution of the hill hold, thereby reducing the cost of the system and improving reliability.
The control does not require a roll back signal or any additional controller functionality but rather relies on the directional properties of a one-way clutch.
The control is robust and works very well even on very small grades.
The scope of applicability of the preferred embodiment will become apparent from the following detailed description, claims and drawings. It should be understood, that the description and specific examples, although indicating preferred embodiments of the invention, are given by way of illustration only. Various changes and modifications to the described embodiments and examples will become apparent to those skilled in the art.
DESCRIPTION OF THE DRAWINGS
The invention will be more readily understood by reference to the following description, taken with the accompanying drawings, in which:
FIG. 1 is a schematic diagram of an automatic transmission;
FIG. 2 is chart showing for each gear the applied and released states of the friction control elements of the transmission of FIG. 1 ; and
FIG. 3 is a graph show the variation of various vehicle parameters as the control is performed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, there is illustrated in FIG. 1 the kinematic arrangement of an automatic transmission 8 . A torque converter 10 includes an impeller wheel 12 connected to the crankshaft 14 of an internal combustion engine, a bladed turbine wheel 16 , and a bladed stator wheel 18 . The impeller, stator and turbine wheels define a toroidal fluid flow circuit, whereby the impeller 12 is hydrokinetically connected to the turbine 16 . The stator 18 is supported rotatably on a stationary stator shaft, and an overrunning brake 20 anchors the stator to the shaft to prevent rotation of the stator in a direction opposite the direction of rotation of the impeller, although free-wheeling motion in the opposite direction is permitted.
The torque converter 10 includes a lockup clutch 22 located within the torque converter impeller housing 23 . When clutch 22 is engaged, the turbine 16 and impeller 12 are mechanically connected to a transmission input shaft 24 ; when clutch 22 is disengaged, the turbine 16 and impeller 12 are hydrokinetically connected and mechanically disconnected. Fluid contained in the torque converter 10 is supplied from the output of an oil pump assembly and is returned to an oil sump, to which an inlet of the pump is connected hydraulically.
Transmission 8 is enclosed in a transmission housing 25 , which is fixed against rotation to the vehicle structure. The input 24 is driven by the engine through torque converter 10 . An output 27 is driveably connected to the vehicle's wheels, preferably through a differential mechanism and a set of transfer gears (not shown).
The transmission 8 includes three epicyclic gearsets 26 , 28 , 30 . The first gearset 26 includes a first sun gear 32 , first ring gear 34 , first carrier 36 , and a first set of planet pinions 38 , supported for rotation on carrier 36 and meshing with first sun gear 32 and first ring gear 34 . Ring gear 34 is secured to carrier 36 and output 27 .
The second gearset 28 includes a second sun gear 40 , second ring gear 42 , second carrier 44 , and a set of planet pinions 46 , supported for rotation on second carrier 44 . Sun gear 40 is secured to input 24 . The output 27 is supported on bearings 47 and secured to a final drive pinion 48 , which transmits torque to the ring gear (not shown) of a differential mechanism 50 . Each of the vehicle wheels 80 , 82 is driveably connected to an output of the differential mechanism 50 .
The third gearset 30 includes a sun gear 52 , ring gear 54 , carrier 56 , and a first set of planet pinions 58 , supported for rotation on carrier 56 and meshing with sun gear 52 and ring gear 54 .
Transmission 8 includes two hydraulically actuated clutches 60 , 62 and three hydraulically actuated brakes 64 , 66 , 68 . The hydraulically actuated clutches and brakes are sometimes referred to as friction elements or control elements. A clutch 60 selectively opens and closes a drive connection between input 24 to carrier 36 and ring gear 42 . A clutch 62 selectively opens and closes a drive connection between sun gear 32 and input 26 . A brake 64 alternately releases and holds sun gear 32 against rotation. A brake 66 alternately releases and holds carrier 36 and ring gear 42 against rotation. A brake 68 alternately releases and holds sun gear 52 against rotation.
Clutches 60 , 62 and brakes 64 , 66 , 68 include plates, which are connected by a spline to a first member, and friction discs, which are connected by a spline to a second member, the plates and discs being interleaved. When hydraulic pressure is applied to a servo that actuates a control element, its plates and discs are forced together into mutual frictional contact, thereby increasing the torque transmitting capacity of the control element and driveably connecting the first and second members. When hydraulic pressure is vented from the servo, the control element transmits no torque, allowing the first and second members to rotate independently.
Although clutches 60 , 62 and brakes 64 , 66 , 68 have been illustrated and described as hydraulically actuated multi-plate clutches and brakes, the invention may be practiced with alternate types of releasable connections including but not limited to dog clutches and brakes, controllable one way clutches and brakes, magnetically actuated clutches and brakes, or electrically actuated clutches and brakes.
A mechanical one-way clutch (OWC) 70 includes an outer race 72 , secured to the housing 25 ; an inner race 74 , secured to carrier 36 ; and an element 76 that alternately engages the races 72 , 74 and produces a drive connection between the races in one rotary direction. OWC 70 overruns or disengages, thereby releasing the inner race 74 for free rotation in the opposite direction. In this way, OWC 70 holds sun gear 42 and carrier 36 against rotation in one rotary direction and releases them to rotate freely in the opposite rotary direction. OWC 70 is arranged in parallel with brake 66 between carrier 36 and housing 25 .
As the table of FIG. 2 shows, first gear is produced by engaging brake 68 . OWC 70 is engaged. When brake 66 is engaged, first gear has engine braking; when brake 66 is disengaged, first gear does not have the engine braking.
Second gear is produced by concurrently engaging brakes 64 and 68 . OWC 70 overruns in each of the forward gears other than first gear. Third gear is produced by concurrently engaging brake 68 and clutch 62 . Fourth gear is produced by concurrently engaging brake 68 and clutch 60 . Fifth gear is produced by engaging clutches 60 and 62 . Sixth gear is produced by concurrently engaging brake 64 and clutch 60 . Reverse gear is produced by concurrently engaging brake 66 and clutch 62 .
When the vehicle is stopped in first gear on a hill having positive slope, negative wheel torque produced by the weight of the vehicle is transmitted from wheels 80 , 82 through the final drive mechanism 84 and transmission gearing, toward the input 24 and engine. FIG. 3 shows wheel brake pressure 90 increasing as the brake pedal is applied and engine speed 92 decreasing when the engine is turned off automatically by an electronic engine control unit (ECU) 94 at 95 . This wheel torque locks OWC 70 , causing it to produce a drive connection between carrier 36 and housing 25 and a torsion reaction to the negative wheel torque.
If under these conditions, transmission 8 shifts from the current gear, first gear, to another gear, the target gear, while the vehicle is stopped in first gear with the engine off on a hill having positive slope, as might occur in response to commands from an electronic transmission control unit (TCU) 93 , the state of engagement of clutches 60 , 62 and brakes 64 , 66 , 68 corresponding to the target gear and the locked OWC 70 will cause transmission 8 to tie-up and will stop the vehicle from rolling backwards on the uphill incline.
Under these conditions, FIG. 3 shows an upshift at 96 to third gear, in which clutch 62 and brake 68 are engaged, OWC remains engage and brake 66 becomes disengaged. Due to the concurrent engagement of OWC 70 , clutch 62 and brake 68 , transmission 8 becomes tied-up, thereby preventing the vehicle from rolling backward down the hill.
Because of the directional properties of OWC 70 , the transmission is not tied-up when the vehicle is stopped on a hill with negative slope. Instead the positive wheel torque produced by the weight of the vehicle unlocks OWC 70 .
FIG. 3 shows that the vehicle operator having released the wheel brakes at 98 , and the engine having been restarted automatically at 100 by the ECU 94 . At 102 , the transmission is shifted into first gear, thereby engaging brakes 66 and 68 . Engine torque propels the vehicle forward preventing rollback 104 on the uphill grade.
In accordance with the provisions of the patent statutes, the preferred embodiment has been described. However, it should be noted that the alternate embodiments can be practiced otherwise than as specifically illustrated and described.
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A method for controlling a vehicle on an uphill incline includes automatically shifting a transmission to first gear, automatically stopping the engine, using wheel torque to maintain a one-way clutch engaged and to hold a transmission component against rotation, preventing vehicle rollback by automatically engaging a target gear and tying-up the transmission automatically restarting the engine, and automatically reengaging first gear.
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This application is a continuation of application Ser. No. 07/961,523, filed Oct. 15, 1992, now U.S. Pat. No. 5,477,249.
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to an apparatus and method for forming images by jetting ink towards an image carrier.
(2) Description of the Related Art
Well known as ink jet image forming apparatus are those applying ink with vibrational energy or electrostatic energy in order to spout it towards a recording medium.
The former includes a Kayser method ink jet recording apparatus (Japanese Patent Publication No. 53-12138) that applies ink held in an ink holding device with vibrational energy generated by piezoelectric vibrators so that the ink is spouted from an orifice.
The latter includes a slit jet recording apparatus (Refer to Denshi Tsuushin Gakkai Ronbunshi Vol: J68-C, No. 2,1985) that has an ink holding device having a slit for ink to jet therefrom to a recording medium, and that is provided with recording electrodes in the slit corresponding to many dots, provided with a counter electrodes behind the recording medium. According to this apparatus, each recording electrode is provided with a voltage responding to image data; these electrodes having voltage applied thereto and the counter electrodes generate the electrostatic field and, as a consequence, the ink is jetted towards the recording medium by the electrostatic attraction force.
The latter also includes such an apparatus as disclosed in U.S. Pat. No. 4,493,550 (Japanese Patent Publication No. 1-40985) in which ink is applied with electrostatic energy by forming electrostatic latent images on the surface of a photoconductive body. A number of holes of a rotatable cylindrical sleeve facing the surface of the photoconductive body are filled with ink so that the electrostatic latent images are bias developed.
The latter further includes an apparatus disclosed in Japanese Patent Application No. 1-235977 in which a development roll is supplied with liquid developer by a cylinder having supply holes, and the liquid developer applied on the roll makes contact with a photoconductive body in order to develop electrostatic latent images.
However, according to the above-mentioned Kayser method ink Jet recording apparatus, the volume of the ink holding device must be large enough to accommodate a large amount of vibrational energy to jet ink. Consequently, a high density multi-nozzle apparatus is hard to be realized.
According to the type including the slit jet recording apparatus, the distance between the recording electrodes can not be shorter than a certain length to avoid cross talks between adjacent recording electrodes. This also makes it difficult to realize a high density multi-nozzle apparatus. In addition, the recording electrodes must be driven separately so as not to cause electrostatic repulsion of ink drops, so that the recording speed is deteriorated.
According to the type including the apparatus disclosed in Japanese Patent Publication No. 1-40985, there are the following problems: first, ink may be evaporated or decomposed during a long term storage, which leads to changing development conditions, secondly, considerable high bias voltage required for development raises the product cost of the apparatus, and thirdly, ink has little color variation and the control of a resistance value is difficult because the ink used for such apparatuses must have a conductivity below about 10 3 Ωcm.
According to the type including the apparatus disclosed in Japanese Patent Application No. 1-235977, there are problems of ink trailing and density changes of the liquid developer caused by evaporation of Isopar.
SUMMARY OF THE INVENTION
The object of this invention is to provide an apparatus and method for forming images, capable of producing high quality images by the use of high density multi-nozzles and various kinds of ink, as well as improving the recording speed and reducing the amount of energy to be consumed.
The above-mentioned object can be achieved by jetting recording liquid onto an image carrier, applying both vibrational energy and electrostatic energy at the same time.
As a result, each energy is less demanded. Thus, not only a unit required to supply vibrational energy to the recording liquid can be minimized, but also the distance between nozzle holes can be shortened because it is more difficult for the vibrational waves become hard to affect each adjacent hole. Therefore, realizing an apparatus having high density multi-nozzles and improved image quality can be made easier.
Moreover, such an apparatus makes it possible to use high viscosity ink which is hard to be jetted only by vibrational energy or high resistance ink which is hard to be jetted only by electrostatic energy such as ink with dispersed pigment in an organic solvent.
Piezoelectric vibrators can be used to apply ink with vibrational energy.
Electrodes can be provided to inject charges into the recording liquid in order to make the best of electrostatic energy.
Both or one of vibrational energy and electrostatic energy can be controlled in order to form images.
Electrostatic energy can be applied by electrostatic latent images formed onto the photosensitive body.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings which illustrate a specific embodiment of the invention. In the drawings:
FIG. 1 is a sectional view of the image forming apparatus of an embodiment of this invention in a stopped state.
FIG. 2 is a sectional view of the same when vibrational energy is being applied thereto.
FIG. 3 is a sectional view of the same when both vibrational energy and electrostatic energy are being applied thereto.
FIG. 4 is a sectional view of the image forming apparatus of another embodiment of this invention in a stopped state.
FIG. 5 is a front view of further another embodiment of this invention in a stopped state.
FIG. 6 is a sectional side view of the same embodiment.
FIG. 7 is a plan view of the same embodiment.
FIG. 8(a), FIG. 8(b), FIG. 8(c), FIG. 8(d), FIG. 8(e) and FIG. 8(f) are plan views of respective units of the same embodiment.
FIG. 9(a), FIG. 9(b), FIG. 9(c), FIG. 9(d), FIG. 9(e) and FIG. 9(f) collectively constitute part of the manufacturing procedure of the same embodiment.
FIG. 10 is a sectional view of another embodiment of this invention.
FIG. 11 is a front view of the same embodiment.
FIG. 12 is a sectional view of another embodiment of this invention.
FIG. 13 is an overall constructional view of the image forming apparatus of another embodiment of this invention.
FIG. 14 is a sectional view of the ink passage in the multi-nozzle head of the same embodiment.
FIG. 15 is a front view of the nozzle plate in the multi-nozzle head of the same embodiment.
FIG. 16 is a sectional view of the vicinity of an ink outlet in the multi-nozzle head of the same embodiment.
FIG. 17 is an overall constructional view of the image forming apparatus of another embodiment.
FIG. 18 is a sectional view of the ink passage in the multi-nozzle head of the same embodiment.
FIG. 19 is a sectional view of the ink passage in the multi-nozzle head of the same embodiment.
FIG. 20 is a table showing the compositions of ink made on an experimental basis.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiment 1!
The following is a description of the image forming apparatus of a first embodiment of this invention referring to FIGS. 1 through 3.
In FIG. 1, the print head 1 of the image forming apparatus comprises a piezo plate 2 polarizing in the direction indicated by an arrow A, an ink supply passage formation member 3 provided thereon, and a nozzle plate 4 further provided thereon. Moreover, an ink room 5 and an inlet 7 to put ink thereto are formed by taking away a portion of the ink supply passage formation member 3.
The piezo plate 2 has a thickness of about 100 μm to 5 mm, including a protruding portion 8 protruding into the ink room 5. This portion 8 is a right square pole of about 30 μm to 250 μm in width, 50 μm to 1 mm in depth, and 40 μm to 1 mm in height.
The piezo plate 2 is provided with a common grounding electrode 9 on top of the protruding portion 8, and a driving electrode 10 on the opposite side. The driving electrode 10 is connected, via a driver 11, with a power source 12, which generates voltage in the range of about 10V to 500V. A predetermined amount of voltage is applied between the two electrodes by a control unit 13 powering the driver 11 on, so that the two electrodes and the piezo plate 2 therebetween are vibrated in the thickness direction of the plate 2. This means that these three components constitute a piezoelectric vibrator 14. AC voltage of 1 kHz to 10 MHz may be added to voltage generated by the power source 12.
The nozzle plate 4 has a thickness of about 25 μm to 1 mm, including a nozzle hole 15, whose cross section can be a circle having a diameter in the range of about 20 μm to 200 μm, or either an oval or a square equivalent thereto, leading out of the ink room 5 to outside the nozzle plate 4. The inside of the nozzle hole 15 is tapered in order to smoothly spout the ink out.
A counter electrode 17 is provided in a position touching the back side of recording paper 16 fed above the hole 15. The counter electrode 17 is connected, via a switch 18, with another power source 19, which generates voltage about 300V to 1 KV. A predetermined amount of voltage is applied between the common grounding electrode 9 and the counter electrode 17 by the control unit 13 powering the switch 18 on, so that the electrostatic field is generated between the two electrodes, and ink charged by touching the common grounding electrode 9 is jetted onto the recording paper 16 by the electrostatic attraction force. This means that the common grounding electrode 9, the counter electrode 17, the switch 18, and the power source 19 constitute the electrostatic field forming device 20, which produces electrostatic energy to jet the ink 6 in the ink room 5 toward the recording paper 16.
The distance between the hole 15 and the recording paper 16 is set in the range about 0.2 to 5 mm. This distance makes it easy to keep the ink 6 away from the recording paper 16 as well as preventing it from not reaching the recording paper 16 by electrostatic resiliency caused among charged ink particles of the ink 6.
The cross-sectional area of the inlet 7 is set below 90% of the minimum sectional area of the hole 15 in order to avoid counterflow of the ink 6.
The control unit 13 powering on the driver 11 and a single or continuous application of pulse voltage to the piezoelectric vibrator 14 makes the vibrator 14 vibrate. Consequently, the ink 6 is jetted towards the recording paper 16 through the hole 15 and then forms an ink meniscus Im as shown in FIG. 2.
In addition, the control unit 13 powering on the switch 18 and the electrostatic field forming device 20 forming the electrostatic field between the common grounding electrode 9 and the counter electrode 17 makes electrostatic attraction force attract the ink meniscus Im towards the recording paper 16. As a result, one or some ink drops Id are formed as shown in FIG. 3, jetted towards the recording paper 16, and then adhered thereto.
The control unit 13 may be constructed so that the electrostatic field forming device 20 is put in operation ahead of the piezoelectric vibrator 14. The unit 13 may also be constructed so that the electrostatic field forming device 20 and the piezoelectric vibrator 14 are both put in operation and ended at the same time. The unit 13 may also be constructed so that either the switch 18 or the driver 11 is put in an on-state all the time and the other is turned on upon request.
This means it is unnecessary that the timing of starting/ending of the application of both vibrational energy and electrostatic energy coincides. The ink does not reach the recording paper 16 when jetting force does not work for lack of vibrational energy or electrostatic attraction force does not work for lack of electrostatic energy. Thus, both vibrational and electrostatic energy as required to be applied at the same time for the ink to jet.
Therefore, it is possible to drop the ink 6 on demand, and it becomes unnecessary to recycle ink used in apparatuses where ink is jetted continuously.
Since the common grounding electrode 9 is in contact with the ink 6, charge injection effects are generated depending on a resistance value of the ink 6 when the electrostatic field forming device 20 is put in operation. However, these effects make the ink 6 easier to be jetted towards the recording paper 16. As a result, voltage applied between the common grounding electrode 9 and the counter electrode 17 by the electrostatic field forming device 20 can be low.
The vibrational energy generated by the piezoelectric energy and the electrostatic energy generated by the electrostatic field forming device 20 compliment each other, demanding less power supply than in the case of jetting the ink 6 independently.
Also, the change of the capacity of the ink room 5 caused by the vibration of the piezoelectric vibrator 14 can be decreased, and as a consequence, the print head 1 can be made more compact by reducing the size of the piezoelectric vibrator 14, as well as lowering voltage applied on the electrostatic field forming device 20.
In the case of an apparatus with multi-nozzles, in addition to reducing the size of the piezoelectric vibrator 14 as above, the distance between two adjacent holes can be shorted because vibrational waves are less likely to affect an adjacent hole. In addition, the distance between two adjacent common grounding electrodes 9 can be shortened because electrostatic repulsion or discharge is less likely to occur, and separate driving becomes unnecessary, which leads to increasing the recording speed. Thus, a construction with multi-nozzles and a compact print head can be easily realized.
Moreover, the combined use of the common grounding electrodes 9 for the piezoelectric vibrator 14 and for the electrostatic field forming device 20 makes the construction of the print head 1 simple, and consequently realizes a compact print head.
Embodiment 2!
As shown in FIG. 4, the print head 101 of the image forming apparatus of this embodiment comprises an ink supply passage formation member 103, and a nozzle plate 104 both united into a single body, and a piezo plate 102 polarizing in the direction indicated by an arrow B, layered under the united body.
A driving electrode 110 and a common grounding electrode 109 are each provided on the side surfaces of the protruding portion 108 in the piezo plate 102; the driving electrode 110 is in contact with a wall 105a of the ink room 105, the common grounding electrode 109 leaving some space from the opposite wall 105b.
FIG. 4 additionally shows an inlet 107 for putting ink 106 into the ink room 105, a nozzle hole 115, a piezoelectric vibrator 114, recording paper 116, a counter electrode 117, and an electrostatic field forming device 120.
The effects of this embodiment are fundamentally the same as those of Embodiment 1 except for the difference of the polarizing direction of the piezoelectric vibrator.
Embodiment 3!
The image forming apparatus of this embodiment is described referring to FIGS. 5 through 9(f).
The print head 201 of this image forming apparatus comprises a glass base 201a of about 1.5 mm in height, 60 mm in depth, and 40 mm in width, and a piezo plate 202 of about 1 mm in height, 24 mm in depth, and 10 mm in width, layered on the front portion of the glass base 201a.
As shown in FIG. 9(a)-(f), the piezo plate 202 is formed as follows. First, resist r is applied all over the upper surface of the piezo plate 202 as shown in FIG. 9(a), a plurality of protruding portions 208 are formed by digging ditches (grooves) in the plate 202 with a dicing saw or the like as shown in FIG. 9(b), electrode metal m is made to adhere onto the protruding portions 208 by evaporating, with the piezo plate 202 slant as shown in FIG. 9(c), the resist r is exfoliated by etching (etching liquid infiltrates in the direction perpendicular to the figure) in order to form piezoelectric vibrators 214 each having a common grounding electrode 209 and a driving electrode 210 as shown in FIG. 9(d), glue b is applied all over the surface of the protruding portions of an upper glass lid 201b having a plurality of ditches (grooves) 205a corresponding to the ink room 205, the glass lid 201b being about 1 mm in height, 9 mm in depth, and 10 mm in width, so that the upper glass lid 201b and the piezo plate 202 are combined with the protruding portions 208 of the piezo plate 202 being set into the ditches (grooves) 205a of the upper glass lid 201b with a space between a bottom surface of each groove 205a and a confronting surface of a protruding portion 208 to define an ink room 205 as shown in FIG. 9(e), and the glue b is baked to be hardened as shown in FIG. 9(f).
The width and the pitch of the protruding portions 208 is about 43 μm and 83 μm respectively. Accordingly, the width of each groove between two of the protruding portions is about 40 μm. The depth of each groove is about 100 μm.
As shown in FIGS. 6 and 7, three glass plates 201c of about 1 mm in height, 7 mm in depth, and 10 mm in width are provided behind the upper glass lid 201b on the piezo plate 202, so that an ink reservoir 221 connected with the ink room 205 is formed between these glass plates 201c and the upper lid 201b. This ink reservoir 221 is about 5 mm in depth and 10 mm in width, its upper surface being covered with, for example, a glass ink lid 201d of about 1 mm in height, 7 mm in depth, and 9 mm in width. The ink reservoir 221 is supplied with ink 206 from outside through an ink supply tube 225.
In addition to the common grounding electrode 209 and the driving electrode 210, a lead connected therewith is formed by aluminum evaporation on the back of the upper surface of the piezo plate 202, and then as shown in FIG. 6, the lead is connected with the print wiring pattern 223 of the print wiring board 222 mounted on the back of the glass base 201a via a wire 224. Each of the driving electrodes 210 is connected to the power source via separate drivers controlled by the control unit so that each driving electrode 210 is powered on and off individually. The above-mentioned print wiring board 222 is about 1 mm in height, 30 mm in depth, and 40 mm in width, consisting of a glass 222a and the print wiring pattern 223 provided thereon.
A nozzle plate 204 made of polyimide resin film or the like is adhered on the front of the piezo plate 202 and the glass base 201a, the nozzle plate 204 having holes 215 corresponding to each ink room 205.
The remaining constructions including the use of the common grounding electrode 209 as the grounding electrode of the electrostatic field forming device 220 are substantially the same as Embodiments 1 and 2.
In this embodiment, each driving electrode 210 is individually powered on or off by an unillustrated control unit driving each driver according to image data; the piezoelectric vibrator 214 in each ink room 205 is separately driven. As a result, vibrational energy is given to the ink 206 in each ink room 205; an ink meniscus is formed and swells out of each hole 215. Then, the ink 206 is jetted towards the recording paper by the force of the electrostatic field formed between the common grounding electrode 209 and a counter electrode behind unillustrated recording paper. Finally, recordings corresponding to image data are formed on the recording paper.
Embodiment 4!
A further another embodiment of this invention is described referring to FIGS. 10 and 11.
The print head 301 of this embodiment has a slit 315 in place of nozzle holes 15, 115, or 215, formed in the ink room 305, and a piezo cylinder 314 is also used as a feed roller for feeding the ink 306 to the slit 315. The piezo cylinder 314, the driving electrode 321 used also as a charge injection electrode for the ink 306, and the common grounding electrode 322 constitute a piezoelectric vibrator 320. The common grounding electrode 322 is also used for the electrostatic field forming device including a counter electrode 317 provided via the recording paper 316. When the electric lines of force generated by applying voltage between the driving electrode 321 and the common grounding electrode 322 pass inside the piezo cylinder 314 in the direction of its axis, the passing area of the electric lines of force in the piezo cylinder 314 expands and contracts in a direction perpendicular to its axis. As a result, the ink 306 is partially given vibrational energy and then jetted towards the recording paper, provided that the electrostatic field is formed.
The remaining parts of this embodiment are constructed in the substantially same way as Embodiments 1, 2, and 3 except that printing is controlled by electrostatic energy controlled by each pixel; the effects are the same as those embodiments. Moreover, the use of the slit 315 avoids clogging of the ink 306 and the use of the feed roller made of piezo enhances ink supply ability, thereby leading to increasing both recording frequency and recording speed.
Embodiment 5!
As shown in FIG. 12, the piezoelectric vibrator 414 of this embodiment is mounted on the head of a nozzle 401 having a hole 415 at the center.
Recording paper 416 and a bias platen roller 417, as the counter electrode of a electrostatic field forming device 420, are positioned in front of the hole 415, the bias platen roller 417 being connected with a power source 419 via a switch print pattern 418.
A protective coat 421 is provided between the common grounding electrode 407 of the piezoelectric vibrator 414 and an ink room 405 inside the nozzle 401, being in contact with both of them. A driving electrode 410, connected with a power source 412 via a driver 411, is formed at the head of the nozzle 401. Ink 406 is held in the ink room 405.
The remaining parts of the construction and effects of this embodiment are substantially the same as those of Embodiments 1 through 4.
Each of the ink rooms 5, 105, 205, 305, and 405 may be constructed by using a structure having a number of fine pores.
Embodiment 6!
As shown in FIG. 13, the image forming apparatus of this embodiment comprises a cylindrical photosensitive body 501, a charger 502 to charge the photosensitive body 501, a multi-nozzle head 504 to supply ink 503 to the surface of the photosensitive body 501, a pressure transfer roller 506 to press recording paper 505 onto the surface of the body 501, a cleaning unit 509 consisting of a cleaning blade 507 and a cleaning roller 508 to clean the surface of the body 501, and an eraser lamp 510 to get rid of charges remaining on the body 501.
The multi-nozzle head 504 has a plurality of ink outlets 512 formed at a certain interval in the axial direction of the photosensitive body 501, an ink reservoir 511 formed behind the head 504 to supply the same amount of ink as that used for development, and an ink passage 513 formed therebetween. A piezoelectric body 514 to vibrate the ink 503 is provided in the ink passage 513, and an electrode 515 as charge injecting device to inject charges into the ink 503 is provided near the ink outlets 512. The electrode 515 is applied about 10V to 500V bias by an unillustrated bias applying device. Such a range of voltage brings out effects of charge injection without causing the deterioration of the quality of the ink 503 or a raise of power cost.
In case that ink with high resistance of about 10 2 Ωcm 10 5 Ωcm is used as the ink 503, the electrode 515 becomes dispensable because the ink 503 inside the multi-nozzle head 504 gets charges by friction with the walls inside the nozzle, which is caused by capillary phenomenon. If the ink is not charged by the friction, polarized charges can be produced by electrostatic induction when the electrostatic field is applied to the ink. As a result, the electrostatic field affects the charges, thereby causing a force to help jet the ink. However, producing a charge injection electrode is still effective in reducing electrostatic energy to jet ink with high resistance.
As shown in FIG. 14, the multi-nozzle head 504 consists of a piezoelectric body 514 having protruding portions 514a . . . and a supporting member 518 having hollowed portions 518a . . . both portions engaging each other. There is some space between the bottom surface of each hollowed portion 518a and the confronting surface of the associated protruding portion of 514a, which is used as an ink passage 513. An electrode 519 is formed at the upper surface of the hollowed portions, while a common electrode 520 is formed at the surface of the other side. Pulse voltage is applied between the electrodes 519 and 520 from an unillustrated power source. The piezoelectric body 514 and the supporting member 518 are combined with each other with glue 521. The surface of the electrode 519 is covered with a dielectric protective layer 522. The electrode 519 can be also used as an electrode for charge injection, the electrode 515 being omitted. If the resistance of the ink 503 is large, the protective layer 522 becomes dispensable.
As shown in FIGS. 15 and 16, a nozzle plate 524 having a number of tapered ink outlets 512 connected with the ink passage 513 is provided at the surface opposite to the photosensitive body 501. The nozzle plate 524 is made from polyimide having a thickness of 100 μm, with holes formed by an excimer laser.
The distance between the ink outlets 512 and the photosensitive body 501 is set to be in the range of about 0.2 mm to 2 mm; the ink 503 is kept away from the photosensitive body 501 without difficulty and the potential of electrostatic latent images, required for applying electrostatic attracting force to the charged ink 503, can be lowered.
Although the pitch of the ink outlets 512 is restricted by machining accuracy and the resolution of images formed, it is desirable to be in the range of about 50 μm to 300 μm. Also, the desirable distance between the electrodes 519 and 520 is in the range of about 10 μm to 5 mm from the viewpoint of strength and cost. In such a case, voltage in the range of about 10V to 500V can be applied between the electrode 519 and the common electrode 520, or 1 kHz to 10 MHz AC voltage can be added to the voltage.
The following is a description of the operation of the above-mentioned image forming apparatus. The photosensitive body 501 is rotated by an unillustrated rotating device in the direction indicated by the arrow therein in FIG. 13. After being evenly charged at about 300V to 1 kV by the charger 502, the surface of the photosensitive body 501 is radiated with light 526 from a light head using an unillustrated liquid crystal display (LCD), a laser beam exposure head, a light emitting diode (LED), PLZT, or the like. As a result, electrostatic latent images corresponding to images to be recorded are formed on the surface of the photosensitive body 501.
On the other hand, the ink passage 513 is supplied with the ink 503 from the ink reservoir 511, at the same time, the piezoelectric body 514 vibrating the protruding portions 514a . . . in thickness vibration mode with pulse voltage applied between the electrode 519 and the common electrode 520. Accordingly, the volume of the ink passage 513 repeatedly expands and contracts, and as a consequence, the ink 503 vibrates and then repeats going in/out through the ink outlets 512. This means that ink near the outlets 512 is not jetted therefrom but reciprocated in the ink running direction of the ink passage 513. At this point, the ink near the outlets 512 is charged the polarity opposite to that of the electrostatic latent images of the photosensitive body 501 by biases applied on the electrode 515. Therefore, the ink near the outlets 512 is, when moved towards the outside of the outlets 512 by vibration, jetted by both the attracting force of the charges of the electrostatic latent images and by vibrational inertia force, finally to adhere on the electrostatic latent images formed on the surface of the photosensitive body. This ink is transferred onto the recording paper 505.
The above-mentioned operation is continued in accordance with the rotation of the photosensitive body 501 and images are transferred onto the recording paper 505. The ink and charges remaining on the surface of the body 501 are gotten rid of by the cleaning unit 509 and the eraser lamp 510 respectively.
Thus, the ink 503 adheres onto the surface of the photosensitive body 501 not only by the vibration of the piezoelectric body 514 but also by electrostatic attracting force, so that bias voltage for development can be reduced, as compared with the case where only the electrostatic attracting force is used. Accordingly, product cost can be reduced. Moreover, substantially any kinds of ink can be used to obtain images of higher quality. Furthermore, the wide range setting of the distance between the photosensitive body 501 and the multi-nozzle head 504 serves to reduce ununiformity of image density.
Embodiment 7!
In this embodiment, light is exposed from inside of a photosensitive body 531 as shown in FIG. 17.
The photosensitive body 531, which is rotated in the direction indicated by an arrow C by an unillustrated driving apparatus, comprises a cylindrical transparent body 532, a thin transparent conductive layer 533 covering the outer surface thereof, a photoconductive layer 534 covering the surface thereof, and a thin ink repellent overcoat layer 535 further covering the surface thereof.
The transparent conductive layer 533 is electrically connected with the cathode terminal of a bias attraction power source 536. Provided inside the photosensitive body 531 are a non-rotatable light writing head 537 for exposing the light conductive layer 534 by radiating light thereto through the transparent body 532 and the transparent conductive body 533, and an optical lens 538. Provided outside the body 531 are a multi-nozzle head 504 to supply ink 503 to positions on the surface of the ink repellent overcoat layer 535, corresponding to positions where light is radiated by the light writing head 537, a rotatable pressure transfer roller 506 to press recording paper 505 onto the surface of the photosensitive body 531, and a cleaning blade 507 to clean the surface thereof. An electrode 515 to charge the ink 503 is provided near the ink outlets 512 of the multi-nozzle head 504. The exposure position of the light writing head 537 faces the outlets 512. The same constructional components as those in FIG. 13 are assigned the same numbers, and detailed description of the construction is omitted.
The light corresponding to image information eradiated from the light writing head 537 passes through the optical lens 538, the transparent body 532, and the transparent conductive layer 533 finally to come into the photoconductive layer 534. As a result, pair of positive photo carriers and negative photo carriers are generated on the photoconductive layer 534. The electrostatic field is formed between the transparent conductive layer 533 applied negative biases by the bias attraction power source 536 and the electrode 515 applied positive biases, and as a consequence, the positive photo carriers are attracted towards the transparent conductive layer 533, so that the negative photo carriers remain on the surface of the photoconductive body 531 as electrostatic latent images, and the potential of portions on the surface of the body 531 onto which the light is eradiated become substantially equal to that of the transparent conductive layer 533. Consequently, a charge injection area is formed between the light writing head 537 and the electrode 515; the ink 503 being charged. On the other hand, the ink passage 513 is supplied with ink 503 from the ink reservoir 511 behind thereof. The protruding portions of the piezoelectric body 514 are displaced in thickness vibration mode by pulse voltage applied between the electrodes. As a result, the volume of the ink passage 513 repeatedly expands and contracts thereby vibrating the ink 503 that, as a consequence, repeats going in and out through the outlets 512. This means that ink near the outlets 512 is not jetted therefrom but reciprocated in the ink running direction of the ink passage 513. Accordingly, the ink near the outlets 512 is, when moved towards the outside of the outlets 512 by vibration, jetted by both attracting force of the charges of the electrostatic latent images and by vibrational inertia force, finally to adhere onto electrostatic latent images formed on the surface of the photosensitive body 531. This ink is transferred onto the recording paper 505. The above-mentioned operation is continued in accordance with the rotation of the photosensitive body 531, and images are recorded on the recording paper 535. The ink remaining on the surface of the body 531 is gotten rid of by the cleaning blade 507. Thus, this embodiment has an electrostatic latent image generation mechanism to form and develop such images at the same time, the mechanism differing from that of Embodiment 6 shown in FIG. 13.
Although the hollowed portions are formed only on one surface of the supporting member 518 in Embodiments 6 and 7, they may be formed on both surfaces of the supporting member 541, engaged with the protruding portions of piezoelectric bodies 542 and 543, and applied with glue 544 as shown in FIG. 18. In this construction, the ink in the ink passage 547 is vibrated by providing electrodes 545 connected with each other onto the upper surface of the protruding portions, and providing common electrodes 546 on the opposite surface of the protruding portions. According to such a construction, the density of the ink outlets can be doubled, thereby improving the resolution. This can be applied to the print head 201 in Embodiment 3.
Although the electrode 519 and the common electrode 520 are respectively formed on the upper surface of each protruding portion of the piezoelectric body 514 and the opposite side thereto so that the protruding portions is vibrated in thickness vibration mode, both the electrodes 519 and 520 may be provided on both surfaces of each protruding portion as shown in FIG. 19 thereby vibrating the protruding portions in length vibration mode like Embodiment 3. According to this construction, the distance between the electrode 519 and the common electrode 520 can be shortened, thereby reducing both the applying voltage to vibrate the piezoelectric body 514 and the product cost of the apparatus.
The image forming apparatuses of all the embodiments mentioned hereinbefore can employ high viscosity (1 cp to 100 cp) ink which is difficult to jet in conventional apparatuses because of the large surface tension, or high resistance (10 2 Ω to 10 15 Ωcm) ink which is difficult to jet only by electrostatic force such as pigment dispersion ink.
The following can be used as organic solvent for such pigment dispersion ink: alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, iso-butyl alcohol, furfuryl alcohol, and tetrahydrofurfuryl alcohol; ketone or ketone-alcohols such as acetone, methyl ethyl ketone, and diacetone alcohol; alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine; amides such as dimethylformamide and dimethylacetonamide; ethers such as tetrahydrofuran and dioxane; esters such as ethyl acetate, methyl benzoic, ethyl lactate, and ethylene carbonate; polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, tetraethylene glycol, polyethylene glycol, glycerine, 1,2,6-hexanetriole, and thiodiglycol; lower alkylmono ether induced by alkylene glycols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol menoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether; diethers; and nitrogen ring compounds such as pyrrolidone.
It is preferable to utilize polyhydric alcohols or alkyl ethers induced by polyhydric alcohol, and more preferable to utilize polyhydric alcohols such as diethylene glycol for further improvement of the pigment dispersion ink properties. Generally, the content of these ingredients ranges 10% to 90% by weight; however, it is desirable to add 20% to 70% of them in order to maintain less temperature dependency of the material value. The content of water generally ranges 5% to 80% in weight, and more preferably 10% to 70%, and most preferably 20% to 70%.
Any organic or inorganic pigments including conventionally used ones can be utilized as the pigment for pigment dispersion ink.
The dispersed particles of these pigments have diameters ranging a few millimicron to a few micron, and it is more desirable to utilize water paste pigment immediately after the production process. The preferable content of the pigment in the pigment dispersion ink ranges 3% to 30% by weight, when influence on tinting strength and viscosity are expected.
Organic pigments are chemically classified as follows: azo series, phthalocyanine series, quinacridone series, anthraquinone series, dioxazine series, indigo series, thioindigo series, perynone series, perylene series, isoindolenone series, and the like.
Well known insoluble pigments are Hansa Yellow, Benzine Yellow, Indathrene Orange, Para Red, Thioindigo Red, Toluindigo Red, both Iudustan Bordeaux and Toluidine Maroon for violet, Indanthrene Blue RS, Phthalocyanine Blue, Phthalocyanine Green and the like.
Well known soluble pigments are auramine and Fast Light Yellow 3G for yellow; Persian Orange and Pigment Scarlet 3G for orange; Lithol Red, Lake Red, Eosin, and Rhodamine for red; Methyl Violet for violet; Victoria Blue and Peacock Blue for blue; and Acid Green and Malachite Green for green.
Inorganic pigments are chemically classified as follows: titanium oxides, lead series, cadmium series, iron oxide series, carbon black, and the like. However, inorganic pigments are generally classified in colors: white, yellow, red, violet, blue, green, black, and others.
White pigments include zinc white (ZnO), lithopone (BaSO 4 +ZnS), titanium white (titanium dioxide, TiO 2 ), white lead (2PbCO 3 -Pb(OH) 2 ), barite (BaSO 4 ), chalk (CaCO 3 ), and clay (kaolin, Al 2 O 3 -2SiO 2 -2H 2 O).
Yellow pigments include chrome yellow (PbCrO 4 ), zinc yellow (ZnCrO 4 ), cadmium yellow (CdS), Antimony Yellow (Naples Yellow, Pb(SbO 3 ) 2 ), ochre (Fe 2 O 3 -xAl 2 O 3 -ySiO 2 ), and Hydrated Yellow, (Mars Yellow, Ferrite Yellow, Fe 2 O 3 nH 2 O).
Red pigments are red iron oxide (Fe 2 O 3 ), red lead (Pb 3 O 4 ), vermilion (HgS), and cadmium red (selenium red, CdS-CdSe).
Violet pigments include Mars Violet (Fe 2 O 3 ), Manganese Violet (Neuremberg, (NH 4 )Mn(PO 4 ) 2 ), and Cobalt Violet, (CO 3 (PO 4 ) 2 --Co 3 (AsO 4 ) 2 ).
Blue pigments include Ultramarine (alminosilicate containing sulfur), Milori Blue (Berlin Blue, Fe(NH 4 ) Fe(CN) 6 !, Fek Fe(CN) 6 !), and Cobalt Blue (CaO-xAl 2 O 3 ).
Green pigments include Chromium Green (a mixture of Chrome Yellow and Milori Blue with Barite added thereto), chromium oxide (Cr 2 O 3 ), Emerald Green (Cu(CH 3 CO 2 ) 2 -3CU(AsO 3 ) 2 ), Cobalt Green (CoO-1OZnO), and natural green (CuCO 3 -Cu(OH) 2 ).
Black pigments are usually called carbon black and include channel black, furnace black, acetylene black, anthracene black, lamp black, pine tar and graphite plumbago.
Dispersion agents utilized for the pigment dispersion ink are: nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyalkyl phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene polyoxypropylene block copolymer; anionic surfactants such as higher alcohol ester sulfate, ester sulfate of polyoxyethylene adduct, and alkylsulfate of fatty acid alkylamide; and cationic surfactants such as higher alkylammonium halide.
The amount of these surfactants added to the pigment dispersion ink is generally less than 20% by weight thereof, and preferably less than 15% by weight.
Also, a resin is added as solvent to the pigment dispersion ink in order to further improve the dispersion of the recording liquid as well as the adhesion to the recording media. More than one natural or synthetic resin among almost all soluble resins as follows are utilized: polymethacrylate resin, polyacrylate resin, acrylic ester-acrylic acid copolymer resin, vinyl resins such as polyvinyl pyrrolidone and polyvinyl butyral resin, hydrocarbon resin, phenol resin, xylene resin, ketone resin, alkyd resin, polyamide resin, polyester resin, maleic resin, cellulosic resin, rosin resin, gelatin, casein, and shellac.
The amount of these resins added to the pigment dispersion ink generally ranges 0.2% to 30% by weight, and preferably, 0.5% to 10%. When less than 0.2 wt/% of the resin is added to the pigment, not only pigment dispersion stability but also the adhesion to recording paper deteriorate.
In addition, other agents such as anti-corrosion, surfactants, lubricant, and perfume can be added to the pigment dispersion ink.
Also, the pigment dispersion ink can be produced through known methods: the above ingredients are kneaded and dispersed by machines such as a homomixer, a ball mill, a homogenizer, a sand mill, and a roll mill.
The above-mentioned pigment dispersion ink has advantages of higher recording density, light stability, water resisting property, and adhesion to the recording paper.
An image forming apparatus is constructed according to the above-mentioned embodiments by using ink (No. 1 through 4) having the composition shown in FIG. 20, and as a consequence, satisfactory images were recorded.
Although the present invention has been fully described by way of examples with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein.
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An ink jet head for jetting ink onto an ink carrier and an ink jet recording apparatus for forming an ink image onto an ink carrier. The ink jet head has a first plate having a plurality of first portions, each first portion having a bottom hollowed from a first surface of the first plate; and a second plate, provided separately from the first plate, having a plurality of second portions corresponding to the first portions, respectively, each second portion having a top which protrudes from a second surface of the second plate and has a piezoelectric material, the second surface being in contact with the first surface so that each top of a second portion confronts to a respective one of the first portions, a space between each top of a protruding portion and the respective one of the bottom of a hollow portion defined as an ink room. The ink jet recording apparatus further includes a driver connected with the second portions to apply an input signal.
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BACKGROUND OF THE INVENTION
The present invention relates generally a safety device for elevators to prevent unintended elevator car movement.
For guiding the elevator car in the case of elevators with guide rails, guide shoes, which are arranged at the elevator car, are employed and such guide shoes are developed either as roller guide shoes or as sliding guide shoes. In the first case, rollers are generally provided with so-called two-dimensional or three-dimensional guides, which roll on appropriate guide surfaces of the guide rail. In the second case, slideway linings slide with small free motion along the guide rails, so that they confer to the elevator car during the vertical transport motion a guide in the horizontal plane. Safety devices, which are physically separate from the guide shoes, are fastened to the elevator car and such safety devices operate to engage the guide rail.
The well-known devices of this kind work in the manner that in case of exceeding the speed limit of the elevator car or respectively in case of over-speed, the safety device is mechanically operated by a speed governor device.
The common safety devices of the state of the art can be categorized according to their construction either to the group of the brake safety devices or the group of the wedge blocking safety devices or the roller blocking safety devices.
A brake safety device is shown in the U.S. Pat. No. 6,131,704, which has a slideway for guiding the elevator car along the guide rail. This safety device includes a forked lever mechanism and a relatively large and heavy electromagnet. With this safety device, the guiding apparatus is functionally separated from the braking device or respectively from the safety device. The usage of such a safety device is therefore uneconomical in particular in the case of low cost elevators with small hoisting height, that is to say for buildings with few floors and low hoisting speeds of the elevator car.
In the case of wedge blocking safety devices or roller blocking safety devices, a loose wedge or loose roller is engaged on a side of the guide rail in order to fit between the stationary guide rail on the one hand and an associated abutment of the safety device on the other hand, by means of the speed limiter, while the safety device block is supported on the opposite side of the guide rail. The prevailing frictional circumstances lead to a further blocking of the clamp body or respectively of the blocking roller and consequently to the braking of the elevator car. Such a blocking roller safety device is described for example in the published European application EP 0 870 719 A1.
Conventional safety devices are applied only in the case of over-speed or in case of inspection work (typically twice per year). Traditional safety devices are in particular of major disadvantage if the elevator car stands at a floor and due to loading, it slips or it falls uncontrolled.
According to the state of the art, an additional so-called creeping protection device prevents the slipping of the elevator car. Thereby, a bolt is pushed into engagement, for example in the appropriate openings of the guide rail, during each stop at a floor, so as to hold in each case the elevator car at the floor level. Further details about the construction and the function of such a creeping protection device are shown in the published European application EP 1 067 084 A1.
A task of the following described invention is therefore to avoid the mentioned disadvantages of the state of the art devices and to create an improved safety device for elevators.
SUMMARY OF THE INVENTION
The safety device according to the present invention has the advantage that it allows, in an excellent manner, an engagement of the safety device in the case of an operating state below the over-speed, that is not so easily possible with the well-known safety devices. Conventional safety devices are never operated in normal operation of the elevator car below the over-speed, which, as a consequence, also makes impossible the early recognition of a possible malfunctioning of the safety device.
A further advantage of the safety device according to the present invention is that it can also be employed as a multifunctional brake device and guiding device for elevators, since it represents a device, which can substitute into one and the same construction three otherwise separated functional units to be employed on an elevator car: these are a guiding device for the elevator car, a safety device and a creeping protection device.
The position of a braking element of the safety device is changeable in a controlled way. Thanks to pre-definition of different positions of the braking element, the safety device can be transferred into different operating states and different functions of the safety device are to be assigned in each case to these different operating states. A mechanism determining the positioning of the braking element allows keeping, in a normal state, the braking element distant from the guide surface of the guide rail. In this normal state, the safety device does not display a braking effect. This normal state of the safety device is adequate for a normal undisturbed drive of the elevator car. The position of the braking element can be changed in a controlled way in such a manner that the braking element touches the guide surface at the guide rail and it is additionally so positioned opposite an abutment that the braking element is not squeezed between the guide surface and the abutment. In this arrangement, the brake is to be arranged in braking readiness, i.e. a state of the readiness for braking. If the safety device is transferred into this state, then a further movement of the elevator car can be possible to a certain extent, since the safety device is not blocked in this state. In the state of braking readiness, an interaction of the braking element with the guide rail is however possible, for example by friction. This interaction between braking element and guide rail makes it possible that the braking element—in a state of braking readiness—is moved in case of a further movement of the elevator car relative to the remaining components of the safety device and opposed to the direction of motion of the elevator car. In case of suitable arrangement of the abutment, the position of the braking element can be changed in such a manner that the braking element comes in addition automatically in contact with the abutment and is squeezed between the guide surface of the guide rail and the abutment. This position of the braking element is called a brake position. In this position, the braking element is blocked and the safety device is arranged in the safety position and in this safety position, a further drive of the elevator car is prevented by the fact that the guide rail is held between the braking element and a retaining element of the safety device.
This safety device can be constructed as a creeping protection device or respectively as a sliding safety device, by transferring the safety device, in case of a stop, into the state of braking readiness. If, under these premises, the elevator car should be additionally loaded, so that the suspension means of the elevator car are stretched and the elevator car is lowered, then the braking element would be moved relative to the safety device. As described above, the safety device can be brought thereby into the safety position, if the elevator car is lowered at least by a defined minimal distance. In case of a suitable arrangement of the abutment, a slipping of the elevator car can thus be prevented, if the elevator car threatens to drop due to an overload.
In case of this safety device, any reversible controlled transition between the normal condition and the condition of the braking readiness can be realised.
This safety device can also serve as guiding device for the elevator car along the guide rail. The retaining element of the safety device is arranged in such a manner that it acts, in normal state of the safety device, as a guiding device for guiding the elevator car alongside the guide rail. The range of motion in a plane perpendicularly to the direction of motion of the elevator car can be arbitrarily limited by further guiding devices. In this way, a guide for guiding the elevator car alongside the guide rail can be functionally integrated into the safety device thanks to a suitable arrangement of the safety device. Such a guide is usually realised, in conventional elevator systems, independently from a safety device with the help of separated guide shoes. The combination of a safety device and of a guiding device or respectively the integrating of a guide into a safety device is particularly economical and entails a favourable weight saving and space saving. The safety device enables a construction in a particularly compact form. For example, the retaining element, and/or one or more guiding elements, and/or the abutment can be developed as part of the walls of a housing for the safety device. This housing can also be constructed as single piece and offers the basis for a simple modular construction of the safety device according to the present invention.
For the safety device, a constructive simple embodiment results if the braking element is developed as blocking roller. This execution form enables a reliable transition of the safety device from the state of the braking readiness into the safety position. This transition is connected with an rolling motion of the blocking roller, which is simply controllable and which can automatically take place by itself even in case of increasing wear of the retaining element and/or of the blocking roller.
The operating mechanism for the positioning of the braking element can be realized in a simple way with the help of an electromagnet. By a suitable pre-definition of the current flowing through the electromagnet, forces can be varied, and with the assistance of these forces, the braking element can be brought in each case into the desired position. Such an operating mechanism can be controlled in a simple manner electronically.
DESCRIPTION OF THE DRAWINGS
The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:
FIG. 1 is a perspective view of a safety device according to the present invention with a blocking roller as a braking element and an electromagnet for operating the safety gear;
FIG. 2 is another perspective view of the safety device shown in FIG. 1 ;
FIG. 3 is a front elevation view of the safety device shown in FIG. 1 ;
FIG. 4 is a bottom plan view of the safety device shown in FIG. 1 ;
FIG. 5 is a top plan view of the safety device shown in FIG. 1 ;
FIG. 6 is a view similar to FIG. 3 with the safety device in a normal state, i.e. with the magnet carrying current;
FIG. 7 is a view similar to FIG. 6 with the safety device in readiness for braking with a retaining element without wear;
FIG. 8 is a view similar to FIG. 7 showing wear of the retaining element;
FIG. 9 is a view similar to FIG. 7 with the safety device in readiness for braking with a retaining element without wear, however with an extension of the suspension means of the elevator car;
FIG. 10 is a view similar to FIG. 9 with the safety device in the safety position with a retaining element without wear;
FIG. 11 is a view similar to FIG. 10 showing wear of the retaining element;
FIG. 12 is a schematic representation of an embodiment of the suspension of the blocking roller of the safety device;
FIG. 13 is a schematic representation of a simpler embodiment of the suspension of the blocking roller;
FIG. 14 is a schematic representation of a guide rail with a guide flange in cross section; and
FIG. 15 is a schematic representation of a further embodiment safety device in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a base 1 , on which a safety device block 2 and an electromagnet 3 of the safety device are firmly installed. The safety device block 2 has a U-shaped cross section formed by two legs 4 and 5 , whereby the inside of the leg 4 is provided with a guide and brake lining 6 . The safety device is installed on an elevator car (not shown) in an elevator system (not shown) and at the same time is aligned on a guide rail 30 (see FIG. 14 ), which serves for guiding the elevator car, in such a manner that a guide flange 31 (see FIGS. 4 and 14 ) of the guide rail 30 is arranged between a braking element, which is developed in the present case as a blocking roller 7 , and the guide and brake lining 6 .
In operation, the guide and brake lining 6 touches a guide surface 32 (see FIG. 14 ) of the guide flange 31 . The leg 4 forms together with the guide and brake lining 6 an oblong retaining element for the guide flange 31 . With the safety device, the elevator car can be held or respectively braked at the guide flange 31 , whereas the guide flange 31 is held between the guide and brake lining 6 and the blocking roller 7 . The other leg 5 is arranged inclined and represents thus an abutment for the blocking roller 7 . So that the elevator car can be braked against a direction of motion, the space between the leg 5 and the lining 6 is narrowed in opposition to the direction of motion in such a manner that the blocking roller 7 can be squeezed between the leg 5 and the guide flange 31 . As clearly shown in FIG. 1 , in the present case the space between the leg 5 and the guide and brake lining 6 is upwards reduced. The safety device represented in FIG. 1 is therefore suitable to react against a descent of the elevator car.
A lever mechanism 8 is operated by an operating mechanism including the electromagnet 3 , whereby the lever mechanism 8 is mounted for swivelling around an axle 9 , which is arranged parallel to a longitudinal surface of the guide and brake lining 6 and perpendicularly to the direction of motion of the elevator car. Preferably, a free end of the lever mechanism 8 is coupled with the electromagnet 3 . Thereby, the location of the blocking roller 7 in the mentioned interspace can be changed depending upon the operating state, preferably in that way that the position of an axle 10 of the blocking roller 7 is changeable along a guide 11 of the lever mechanism 8 , for example via rolling of the axle 10 alongside the guide 11 .
The safety device block 2 is preferably constructed as single piece with the leg 4 , acting as retaining element, and the leg 5 , acting as abutment. The legs 4 and 5 are rigidly connected to the base 2 in such a manner that when blocking further movement of the blocking roller 7 , the leg 4 together with the guide and brake lining 6 is pressed against the guide flange 31 on the side opposite the blocking roller 7 .
The lever mechanism 8 includes for example a part, which serves as a suspension 12 for the blocking roller 7 . This suspension 12 comprises the guide 11 , in which the axle 10 of the blocking roller 7 is moveably placed. The guide 11 can be formed as a groove or respectively as an oblong recess. In order to operate the lever mechanism 8 , the electromagnet 3 exhibits a holding or tie bolt 13 connected with the free end of the lever mechanism 8 , and such holding or tie bolt 13 can be moved in its lengthwise direction relative to the electromagnet 3 , by means of a magnetic field generated with the electromagnet 3 , as indicated in FIGS. 1 and 6 by double headed arrows.
In FIG. 2 , the base 1 is represented with the safety gear block 2 and the electromagnet 3 in such a manner that a first range with the U-shaped cross section between the two legs 4 and 5 and a second range with an L-shaped cross section as well as a surface structure 14 of the guide and brake lining 6 are clearly visible. In the shown example, the surface structure 14 exhibits an X-shaped applied profile. Over a support 15 , being connected with the base 1 on the side of the leg 5 applied from the blocking roller 7 , those forces that act on the leg 5 when braking can be absorbed by the base 1 .
From the FIGS. 3 , 4 and 5 , a free space 16 is clearly evident and such free space 16 is reserved for the guide flange 31 of the guide rail 30 . In FIGS. 4 and 5 , a part of the guide flange 31 is shown in section.
As shown in FIGS. 1-3 and 6 - 11 , a spring 17 is arranged at the electromagnet 3 and the electromagnet 3 is electrically controllable by means of a release mechanism. In case of a suitable electrical control of the electromagnet 3 , the holding or tie bolt 13 can be moved and the free end of the lever mechanism 8 can be deflected against a restoring force of the spring 17 . At the same time, the lever mechanism 8 is rotated around the axis of rotation 9 around an appropriate bevel and the position of the blocking roller 7 in the interspace between the leg 5 and the guide flange 31 is changed in a controlled way. In normal operation (driving the elevator car), the electromagnet 3 is current-activated and the holding or tie bolt 13 is held against the spring resistance in an upper extreme position in order to keep the blocking roller 7 distant from the guide flange 31 . In this arrangement, the spring 17 is therefore compressed. If the electromagnet 3 is not current-activated, the holding or tie bolt 13 is arranged under the effect of the spring 17 in a position, which is shifted downwards in such a manner that the blocking roller 7 is brought into contact with the guide flange 31 ( FIG. 7 ). If the blocking roller 7 touches the guide flange 31 , then the premise is created that the safety device achieves a braking action by an interaction with the guide flange 31 . The safety device is then either in the state of braking readiness (braking readiness position), as long as the blocking roller 7 is not squeezed between the guide flange 31 and the leg 5 , or in the safety state wherein the blocking roller 7 is squeezed between the guide flange 31 and the leg 5 in a brake position.
In the case of power failure, just as with an appropriate control of the electromagnet 3 , the safety device is therefore due to the effect of the spring 17 in the braking readiness state or the safety state.
In FIG. 6 , the elevator is in the operating state and in such operating state, the elevator runs undisturbed (standard drive) and the safety brake is arranged in the rest position. The electromagnet 3 is current-activated and the lever mechanism 8 is deflected in such a manner that the blocking roller 7 is out of contact with the guide rail 30 . In this position, the axle 10 of the blocking roller 7 rests under effect of the weight on a lowest end or point 27 of the guide 11 of the lever mechanism 8 .
FIG. 7 corresponds to an operating state in which the elevator stands for example at a floor stop, so that no relative motion between the guide rail and the elevator car or respectively the safety device takes place. The current supply to the electromagnet 3 is interrupted, whereupon the lever mechanism 8 is so far swiveled that the blocking roller 7 abuts against a zone or portion 20 of the guide flange 31 of the guide rail. The safety device is in the braking readiness position, and no additional loading of the elevator car took place. The blocking roller of 7 rests unaltered at the lower end 27 of the guide 11 . FIG. 8 corresponds to the same case, however with a wear of the guide and brake lining 6 of for example 2 mm within a zone or portion 21 . In this case, the bolt 13 is somewhat further extended and the blocking roller 7 approaches thereby nearer to the leg 4 , since the guide and brake lining 6 became thinner due to wear. The axle 10 of the blocking roller 7 is still placed—as in the case of the FIG. 7 —at the lower end 27 of the guide 11 .
FIG. 9 serves for the explanation of an operating state, in which the elevator stands and the elevator car was loaded and is lowered consequently within the limits of the elastic resilience of the suspension or respectively of the suspension means, whereupon a movement of the safety device occurred relative to the stationary guide flange 31 of the guide rail 30 . During the lowering of the elevator car, the blocking roller 7 , which is already adjacent to the guide rail in accordance with FIG. 7 , has been put into an anticlockwise rotation under effect of the friction with the guide rail 30 and is rolled along the guide 11 . The axis of rotation 10 of the blocking roller 7 has taken thereby a new position 22 (in FIG. 9 defined by the lowest point of the axis of rotation 10 ), which is shifted opposite to the direction of motion of the elevator car. At the same time, the blocking roller 7 is pushed along closer to the leg 5 , however not yet squeezed between the leg and the guide rail. That the blocking roller 7 has automatically changed its position alongside the guide 11 with the described lowering of the elevator car is a consequence of the superposition of all forces affecting the blocking roller 7 . These forces are in particular:
(i) the friction between the blocking roller 7 and the guide rail 30 ;
(ii) the friction between the axle 10 of the blocking roller 7 and the guide 11 ;
(iii) the weight of the blocking roller 7 ; and
(iv) the force, which is exercised by the guide 11 due to the effect of the forces of the electromagnet 3 and of the spring 17 on the blocking roller 7 .
If the safety device is as described in a condition of braking readiness, then the blocking roller 7 is in a state of equilibrium, which changes only if the elevator car changes its position. The state of equilibrium is characterised by the fact that with a suitable adjustment of the guide 11 relative to the guide rail 30 , an equilibrium of the forces is set in such a manner that only in a case of a lowering of the elevator car and consequently of the safety gear block 2 , the lever mechanism 8 is swivelled relative to the guide rail 30 under effect of the force of the spring 17 (with a lowering of the safety device relative to the guide rail 30 , the spring 17 lengthens in its lengthwise direction) and during this swivelling motion the blocking roller 7 rolls alongside the guide 11 and at the same time realises a movement relative to the safety gear block 2 , this movement being parallel to the guide rail 30 and opposite the direction of motion of the elevator car. In this way, in the state of braking readiness, the blocking roller 7 takes on a new state of equilibrium after each lowering of the elevator car, and such state of equilibrium exhibits a reduced distance from the leg 5 . Therefore, the blocking roller 7 passes through a series of states of equilibrium when lowering the elevator car, until the blocking roller 7 is finally squeezed between the leg 5 and the guide flange 31 and consequently brought into the brake position. The initial tension of the spring 17 and the form of the guide 11 can be co-ordinated for optimization purposes, in order to reliably control the described change of the position of the blocking roller 7 relative to the guide 11 and to the leg 4 in space and time.
If the elevator car is ready for the continuation of the drive, the electromagnet 3 is current-activated and in this manner the lever mechanism 8 and the blocking roller 7 are moved under effect of the electromagnet 3 and of the gravitational force in such a way that the safety device arrives again into the normal or rest position. The described operating sequence recurs with each “stop”. The resilience of the suspension and of the suspension means of the elevator car and the geometrical proportions of the safety device are thereby co-ordinated in such a way that by loading the elevator car beyond the permissible maximum weight, the blocking roller 7 rolls so far alongside the guide 11 that the blocking roller 7 is squeezed between the inclined leg 5 and the guide rail and the safety gear is shifted into the safety or brake position. In this way, the function of a creeping protection device is realised with the safety device.
FIG. 10 shows a state in which the safety device is shifted into the safety or brake position. As a result of a relative motion between the safety device and the guide flange 31 of the guide rail 30 , whose amount exceeds the useful load range described in connection with FIG. 9 , the blocking roller 7 moves along the guide 11 up to a position 23 and is now squeezed between the guide rail and the leg 5 . The prevailing frictional proportions in a zone or portion 24 lead to further blocking of the blocking roller 7 in case of a further on appearing relative motion. At the same time, the leg 5 is finally pushed from the blocking roller 7 in a direction (left in FIG. 10 ) away from the guide rail or respectively the blocking roller 7 is pressed against the guide flange 31 . FIG. 11 shows the state for example in case of a 2 mm wear of the guide and brake lining 6 with a strong friction in a zone or portion 25 . In the final case, the axle 10 takes an extreme position 26 within the upper range of the guide 11 .
After that the safety device is set into the safety or brake position, the force of the electromagnet 3 is not sufficient any more in order to release the blocking roller 7 from the blocking and to release again the movement of the elevator car, but rather the safety device is to be released in a so-called reversal drive from the safety position, before the elevator car can be moved again downwards.
The leg 4 has a flat surface, as evident from the figures. The guide and brake lining 6 preferably consists of a material, which preferably exhibits a small coefficient of friction during a small surface pressure and a large coefficient of friction during a large surface pressure. Such materials are for example used in multi-plate clutches or brake linings, well known from the automobile industry point of view. The characteristic of the coefficient of friction that the guide and brake lining 6 exhibits as a result a transition zone is as steep as possible between a range with a low coefficient of friction and a range with a very high coefficient of friction. This enables the utilization of the guide and brake lining 6 for the purpose of braking (in case of a large contact pressure) and for the purpose of guiding (in case of a small contact pressure) subject to the size of the contact pressure between the guide and brake lining 6 and the guide flange 31 . In case of a suitable material choice, it is therefore possible to undertake the provided functional combination, according to the present invention, of a brake safety device and a guiding device into a single multi-functional brake in the shape of the present safety device and to optimize independently from each other their employment as a brake device or as a guiding device for the elevator car.
As particularly evident from the FIGS. 6 to 12 , the guide 11 does not exhibit a straight-lined form for the axle 10 of the roller 7 , but it is provided with a middle portion 28 , in which it makes first a curve to the right and then a curve to the left. This curvature course can be optimized depending upon each employment. The detailed course of the guide 11 between the lower end 27 and the upper extreme position 26 determines in which measure the blocking roller 7 changes its position relative to the leg 5 , if the safety device block 2 is moved around a given measure alongside the guide rail 30 . This change is anyhow non-linear as a function of the path alongside the guide rail 30 , if the guide 11 exhibits a curved course.
A peculiarity, which can be brought back to the special course of the curvature of the guide 11 , is represented in FIG. 12 . The curvature of the guide is at the same time exaggeratedly represented for reasons of clarity. The suspension 12 of the lever mechanism 8 is developed in accordance with FIG. 12 in such a manner that, depending on the operating state, the position of the axle 10 of the blocking roller 7 is changed along the guide 11 at two locations in an at least approximately discontinuous manner. The average lengthwise direction of these grooves or oblong recesses forms preferably an angle with the direction of motion of the elevator car. The guide 11 exhibits, because of its curvilinear course, several locations at which the blocking roller 7 can take, due to its form, a stable position—in the following designated as locking position—if the blocking roller were transported alongside the guide of 11 to one of these locking positions as a result of the mechanisms described before. If the blocking roller 7 has arrived alongside the guide 11 at one of these locking positions, then the lever mechanism 8 takes under the effect of the spring 17 a position in which the guide 11 supports the blocking roller 7 in such a way, that the position of the blocking roller 7 is not substantially influenced through small changes in the deflection of the lever mechanism 8 and is therefore stabilized, in particular against the influence of the weight of the blocking roller 7 . The suspension 12 has a lower locking position at the lower end 27 of the guide 11 for the normal operation in the normal state of the safety device in case of current-activated electromagnet 3 , a middle locking position within the middle portion 28 or above the middle portion 28 of the guide 11 for the operation as creeping protection device or respectively for the operation of the safety device in the safety position in each case with a not current-activated electromagnet 3 , and an upper locking position at an extreme position 26 ′ at the upper end of the guide 11 .
FIG. 13 shows a guide 29 , which can be used as a simplified alternative to the guide 11 in the safety device and which exhibits a linear course. In the example according to FIG. 13 , the guide 29 does not exhibit any change of direction. In this case, there is no locking position in the middle portion of the guide 29 for more precisely controlling the position of the blocking roller 7 in case of operation as creeping protection device, in contrast to the example in accordance with FIG. 12 .
FIG. 14 shows an example of the simple guide rail 30 with the guide flange 31 , whose thickness is so designed that it fits into the free space 16 (see FIGS. 3 and 5 ). The guide rail 30 with the guide flange 31 is vertically arranged in the elevator hoistway. Preferably, two guide rails with guide flange are arranged laterally to the elevator car. The elevator car carries in this case two or four safety devices, which stand in interaction with the guide rails. The principle of the present invention is however independent from the thickness or form of this guide flange, provided that at least one guide surface 23 is available.
The momentary position of the electromagnet 3 and, thus, the condition of the safety device is ascertained in the shown example by two switches 18 and 19 , which supervise the position of the holding or tie bolt 13 or respectively the deflection of the lever mechanism 8 and consequently also the operating state of the safety device. The one switch 18 is provided in order to indicate whether the safety device of the elevator installation is in readiness and the other switch 19 (also called “brake—in engagement—switch”) is provided in order to indicate whether the safety device is in the safety position. The brake—in engagement—switch is advantageously integrated into the safety circuit of the elevator.
In a further embodiment of the invention, the safety device can exhibit a two-dimensional or even a three-dimensional guide for the elevator car at the safety device block. Such an example is represented in FIG. 15 . The safety device, in accordance with FIG. 15 , exhibits beside a blocking roller 67 , which is guided alongside the guide 29 , a retaining element 64 with a guide and a brake lining 66 and an abutment 65 . A lever mechanism 68 is available, which is pivoted as indicated by a double arrow 61 . Through the lever mechanism 68 , the blocking roller 67 can be brought into a brake position, and in such brake position, the blocking roller 67 is squeezed between a guide surface 63 of an oblong guide flange 62 installed in the elevator hoistway and the abutment 65 . The safety device comprises an operating mechanism (e.g. an electromagnet, or a mechanical, or pressure controlled mean), which is arranged in such a manner that it acts upon the blocking roller 67 by means of this operating mechanism and lever mechanism 68 in order to change the position of the blocking roller 67 with respect of the oblong guide flange 62 . The safety device is thereby characterised in accordance with FIG. 15 by an additional guiding device 69 that is provided, whose guide surface is provided with a guide lining 70 . The guide lining 70 can be realised in a different way in respect to the guide and brake lining 66 , for example as a wear resistant lining with a small coefficient of friction. The latter is meaningful since the guiding device 69 has exclusively a guide function and, in contrast to the retaining element 64 , it does not deploy any braking action.
Furthermore, a suitable safety switch (not shown) can be provided, which measures and/or controls the wear of the guide lining and in case of excessive wear, it stops the elevator.
The multi-functional safety device is brought into the state of braking readiness with each stop in the regular driving of the elevator in accordance with the invention, as the current of the electromagnet is switched off. The execution of the safety device allows the lowering of the elevator car in the stopping place in case of loading, without the safety devices getting blocked with the guide rail. By moving the safety devices at each stop, a quasi-automatic checking of the functional efficiency of the multi-functional rail brake takes place.
There are further conceivable embodiments of the invention, which emanate from modifications of the described safety devices. As a braking element also wedges, ellipsoids or other objects can be considered in place of the described blocking roller, if they are squeezable due to their form. Instead of the described lever mechanism, each mechanism can be considered if with this mechanism the position of the braking element can be changed in a controlled manner, in order to guarantee the described functionality of the safety device. The described electromagnet could be replaced by another operating mechanism, which is suitable for changing, via a controlled force effect, the position of the braking element in such a manner that the safety device changes from the normal state into the state of the braking readiness and inversely. Obviously, the described switches 18 and 19 can be replaced also by a sensor, which is suitable to characterize the momentary position of the braking element or respectively their change in order to seize the momentary operating state of the safety device and as the case may be to derive thereon signals for controlling the elevator. The safety device can also be developed for braking for any direction of motion alongside a guide rail. The abutment must be merely aligned according to the respective suitable purpose relative to the guide rail, in order to enable a squeezing of the braking element. Further on, the braking element must be guided accordingly, in order to enable an automatic transition between the normal position of the safety device in the state of the braking readiness and from there in the respective safety position. In case of suitable guidance of the braking element and a suitable arrangement of the appropriate abutment, a single safety device can be designed on the basis of the present invention for the purpose of braking alongside each of the two directions of motion, which can be realised alongside a guide rail.
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.
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A safety device brakes an elevator car with a guide rail exhibiting an oblong guide flange. The safety device includes a base carrying a retaining element and an abutment with the guide flange positioned therebetween. A mechanism squeezes, when braking, a braking element blocking roller between the guide flange and the abutment. The mechanism, co-operating with an electromagnet, moves the braking element in a controlled way between different positions associated with different operating conditions of the safety device.
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BACKROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a high-speed spindle unit for machine tools for machining workpieces.
[0003] 2. Discussion of Related Art
[0004] Modem high-speed spindles are driven with speeds up to several ten thousand rpm, which is, of course, only possible with fully functional and highly precise bearings. The precision bearings used for the spindle of such high-speed spindle units are, however, highly susceptible to pressure or shock loads acting on the tool and spindle body. These loads are, in particular, transmitted to the housing via the front roller bearing. This holds true for impact and shock loads acting on the clamped tool or on the tool spindle, or both. These loads are caused by a collision with a machine part or the workpiece during shifting movements of the workpiece or the spindle unit, or both, while no machining operation is carried out.
[0005] Further, extremely high loads may occur during a machining operation, for example, in case of an excessive feeding movement, an erroneously selected cutting tool, or a change of the material structure of the workpiece. In both cases of stress the impact-like shock loads or peak loads may damage the high-precision roller bearings, and thus, affect the true running properties, which are particularly critical. This may lead to a possibly permanent damage of the components involved, which will inevitably require an exchange of the spindle unit.
SUMMARY OF THE INVENTION
[0006] It is an object of the invention to provide a high-speed spindle unit in which a deterioration of the front bearings of the spindle, due to mechanical peak loads as well as damage caused by overload, can largely be avoided.
[0007] According to the invention, this object is addressed by dimensioning a gap between the two faces so that the two faces are in contact with each other when an axial load acting on the spindle has reached a certain value. The load is directly transmitted from the spindle component to the housing component under avoidance of the roller bearing parts.
[0008] If the spindle receives a shock-like axial load, for example, because of a collision with the workpiece while the tool is inactive or idle, the impact forces, up to a certain tolerable magnitude, are transmitted to the housing via the clamped tool holder, the spindle body and the inner race of the front roller bearing while the components are deformed to a permissible degree without any damage being caused. If the shock loads exceed the predetermined magnitude, the ring nut attached to the rear spindle body comes into pressure contact with the associated face of the terminating ring of the housing after the gap has closed so that the peak pressures are directly introduced into the housing and the bearing components are withdrawn from the influence of the peak loads.
[0009] If axial loads which are within predetermined limits, act on the tool during a machining operation, they are transmitted from the spindle body to the housing via the roller bearings in the manner described above. The width of the gap according to the invention decreases depending on the magnitude of the load. Only after the gap has fully closed under a heavy load is there a pressure contact between the rotating rear face of the ring nut and the front face section of the stationary terminating ring of the housing, which results in a strong heating of the paired frictional surfaces.
[0010] The described function of the gap according to the invention gives rise to a relief of the roller bearing parts in case of abnormally large loads acting on the spindle. Since the individual surfaces of the paired friction surfaces will regularly tarnish, or change their color, it can be determined by visual inspection during maintenance work whether the spindle was driven with excessive loads during operation which exceeded the manufacturer's specifications.
[0011] For obtaining the intended effects, the dimensions of the gap according to the invention are of substantial importance. The gap width is determined for different kinds of spindles based on different constructional and operational parameters of the respective spindle unit. So far, gap widths in the range of 50 μm to 100 μm have been found to be suitable.
[0012] The effects described above apply analogously for loads acting in a direction transverse or inclined with respect to the spindle axis. For compensating such loads a circumferential gap accurately dimensioned within predetermined limits is provided between the distance ring and the terminating ring of the housing.
[0013] To cope with the detrimental effects of the occurrence of friction welding, an advantageous further development of the invention is that the spindle component and the housing component consist of a friction welding resistant material, at least at the contact areas of their friction surfaces. In this way the occurrence of a permanent connection of the components caused by friction welding can be prevented. For obtaining that effect one or both of the friction surfaces may also be coated with a friction welding resistant material.
BRIEF DESCRIPTION OF THE DRAWING
[0014] Further particularities and advantages of the invention will become clear from the following description of preferred embodiments with reference to the drawing, in which:
[0015] [0015]FIG. 1 is an axial cross sectional view of the front end portion of a high-speed spindle unit according to the invention;
[0016] [0016]FIG. 2 is an enlarged view of details of a portion of FIG. 1; and
[0017] [0017]FIG. 3 is an enlarged portion of the upper spindle bearing according to another embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] The high-speed spindle unit shown comprises a spindle 1 driven on its rear side by a drive unit (not shown), the front end portion of the spindle being supported in two roller bearings 2 and 3 arranged in a row within a multiple-component housing 4 . Housing 4 comprises outer spindle housing 5 in which housing portion 6 and front bearing housing 7 are accommodated. Terminating ring 8 of the housing, having a profiled cross section, is fixed to the front face of bearing housing 7 by means of screws. The terminating ring of the housing is provided with central ring groove 10 on its radial rear face, which faces front roller bearing 2 . The radially outer portion 11 of the ring groove is supported by stationary outer bearing race 12 of roller bearing 2 . As can be seen in FIG. 2, the front portion of terminating ring 8 of the housing is formed with stepped radial front surfaces 13 , 14 , and 15 .
[0019] In a central bore of spindle 1 , collet chuck 16 is provided for clamping tool holder 17 in the front recess of the spindle, the collet chuck being of a conventional type so that its further description will be omitted. The inner bearing shells or inner races 18 and 19 of roller bearings 1 and 2 have an approximately rectangular cross section and are fixedly attached to the front portion of spindle 1 . The spindle has step 20 , against which inner race 19 of rear roller bearing 3 is supported. Between inner races 18 and 19 of the roller bearings is clearance-free spacer ring 21 fixedly attached to spindle 1 . The spacer ring is surrounded by cooling ring 22 which has a profiled cross section. The cooling ring is provided with central ring chamber 23 and a respective circumferential ring groove in both of its faces. Cooling channel 24 extending in an angled manner in housing portions 7 , 6 and 5 terminates in the ring chamber. As can be seen particularly in FIG. 2, the radially outer portions of the faces of the cooling ring are in contact with the two outer bearing races of roller bearings 2 and 3 .
[0020] On the front face of inner race 18 of front roller bearing 2 is distance ring 25 , which is fixedly attached to spindle 1 . The rear face of this distance ring is in contact with inner race 18 .
[0021] Threaded bush 26 is formed with a plurality of steps in its outer circumference which correspond to step surfaces 13 , 14 , and 15 of terminating ring 8 of the housing as shown. Bush 26 is fixedly screwed to the leading end portion of spindle 1 . A radially inner portion of radial rear face 27 of threaded bush 26 is supported by the front face of distance ring 25 . According to the invention, a continuous ring-shaped gap indicated by reference numeral 29 in FIG. 1, the gap has an accurately dimensioned width and is provided between the radially outer section of face 27 and radial surface 13 of terminating ring 8 of the housing in the embodiment according to FIGS. 1 and 2. The function of the gap will be described in more detail below.
[0022] Another circumferential gap 30 with precisely set dimensions is formed between the mantle surface of distance ring 25 and the opposed inner circumferential surface of terminating ring 8 of the housing. In addition to gaps 29 and 30 having accurately dimensioned gap widths, another wider continuous gap is provided between the rotating spindle components and the stationary housing components to enable a rotation of the spindle body inside the housing. The width of that continuous gap, however, is set so that even in case of extreme peak loads the rotating components associated with the spindle cannot contact the stationary components associated with the housing.
[0023] Gaps 29 and 30 provided according to the invention are to protect roller bearings 2 and 3 against an overload caused by peak loads acting on the clamped tool or the spindle body. If the tool is extended in the direction of the spindle axis by a feeding movement while the spindle is standing still and the tool hits a stationary element, for example, the workpiece, the resulting shock is transmitted in the axial direction to the spindle through tool holder 17 . In prior art machines the impact forces caused by the shock were introduced into the dimensionally stable housing portions via the roller bearings alone, which resulted in the damage mentioned above, particularly of the front roller bearing in cases of higher loads. The provision of accurately dimensioned ring-shaped gap 29 extending in the radial direction has the effect that normal axial shock loads acting on the spindle are introduced into housing part 7 via threaded bush or ring nut 26 , distance ring 25 and front roller bearing 2 , as long as the shock loads do not exceed a predetermined value. With an increase of such shock loads the width of gap 29 will be reduced. If the shock loads have reached a certain magnitude gap 29 will be closed so that the radially outer portion of rear face 27 of threaded bush 26 will be in contact with opposed surface area 13 of terminating ring 8 of the housing. Therefore, the shock loads acting on spindle 1 are directly introduced into terminating ring 8 via threaded bush 26 and paired ring-shaped surfaces 13 and 27 . Note that terminating ring 8 of the housing is rigidly connected to bearing housing 7 of housing 4 . This means that the axial peak forces will no longer act on inner bearing shell 18 via distance ring 25 so that front roller bearing 2 is protected against extreme stresses.
[0024] The width of ring-shaped gap 29 according of the invention is selected on the basis of different constructional and operational parameters so that the loads occurring are introduced into housing 4 via front roller bearing 2 in the conventional way, up to a harmless value, while the width of gap 29 decreases depending on the magnitude of the axial load. Below the load critical for roller bearing 2 , gap 29 will already be closed so that the axial stress forces are directly introduced into terminating ring 8 from this moment on. It is obvious that the widths of gap 29 and circumferential gap 30 are each selected depending on the specific parameters of the respective spindle type.
[0025] Similar effects and results will occur when the idle spindle collides with a machine part, for example, a workpiece, due to a lateral relative movement, which will result in preferably radial or transverse loads acting on the spindle which were also introduced into the housing only via the roller bearings in the spindle units conventionally used. For the protection of mainly front roller bearing 2 , circumferential gap 30 according to the invention is provided between distance ring 25 and the opposed surface of terminating ring 8 , the gap width of gap 30 being set within a range of about 50 to about 120 μm, depending on the respective constructional and operational parameters of the spindle type concerned.
[0026] If axial or transverse peak loads which exceed the thresholds mentioned above and leading to a closure of the one or the other gap 29 and 30 occur while the spindle unit is rotating at a high speed during a machining operation, friction welding can occur at the surfaces which are then in contact with each other. The intensity of such friction welding must be limited to prevent the spindle from jamming. This case, however, rarely occurs in practice, that is, only if the maximum loads determined by the manufacturer are exceeded due to misdemeanour during operation. To reduce the detrimental effects of such friction welding under extremely high loads, distance ring 25 , ring nut 26 , and terminating ring 8 consist of materials selected in view of high heat resistance or good sliding properties at high temperatures, or both, at least at the wall portions defining gaps 29 and 30 . Such materials comprise, for example, special ceramic materials, possibly containing reinforcing fibres, hard steel, brass, bronze, or any of the foregoing alone or in combination. The respective surfaces of those components may also be coated with such materials in an appropriate thickness to cope with extremely high temperatures in the area of the pairing friction surfaces or to prevent welding effects from occurring, or both.
[0027] The variant shown in an enlarged axial cross sectional view in FIG. 3 corresponds to the embodiment according to FIGS. 1 and 2 in its constructional features so that corresponding components are indicated by the same reference numbers. This variant differs from the embodiment according to FIGS. 1 and 2 in that radial ring-shaped gap 40 dimensioned according to the invention is formed between a rear ring-shaped collar of ring nut 26 a and a ring-shaped surface on the front side of terminating ring 8 a. The width of ring-shaped gap 40 is in a range from about 10 μm to about 80 μm, similar to the embodiment according to FIGS. 1 and 2, and will be determined for the respective spindle type depending on the specific conditions and parameters. In the variant according to FIG. 3, ring nut 26 a attached to the front end portion of spindle 1 comprises radially inner shoulder 41 , the end surface of which is in contact with the face of distance ring 25 a. The distance ring is narrower here than in the earlier embodiment and is fixed on spindle 1 by appropriate means such as by shrink fitting. Between the outer circumferential surface of distance ring 25 a and the opposed surface of terminating ring 8 a a relatively wide ring-shaped gap is provided. The width of this gap excludes any mutual contact of components 25 a and 8 a, even under extremely high peak loads. Precisely dimensioned circumferential gap 39 , functionally corresponding to circumferential gap 30 of the embodiment according to FIGS. 1 and 2, is located between the outer circumferential surface of inner shoulder 41 of ring nut 26 a and an inner circumferential surface of terminating ring 8 a in the variant according to FIG. 3. The variant described above and shown in FIG. 3 has the advantage of a facilitated maintenance and inspection since distance ring 25 a is withdrawn from the influences of the peak loads and can remain on spindle 1 . Two ring-shaped or circumferential gaps 39 and 43 , relevant in view of the peak loads, are located between ring nut 26 a and terminating ring 8 a. Both components can be removed and replaced if required in a simple manner by detaching the respective screw connection. In this way several hours of mounting time can be saved.
[0028] The invention is not limited to the embodiments shown but includes spindle units in which other ring-shaped gaps or circumferential gaps are dimensioned between the rotating spindle parts and the stationary housing parts in the manner explained above to protect load sensitive components.
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A high-speed spindle unit for milling and drilling machines. The spindle unit has a spindle housing on the front end portion of which a terminating ring detachably mounted and a rotationally driven tool spindle which is supported in at least a front roller bearing inside the spindle housing, a ring nut being attached to the front end portion of said spindle. Between the terminating ring and the ring nut a pre-dimensioned ring-shaped gap extending in the radial direction is formed, the gap width of the gap being decreasable to zero with increasing axial load acting on the spindle.
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This is a continuation of international application Ser. No. PCT/EP94/01352, filed Apr. 28, 1994.
This is a continuation of international application Ser. No. PCT/EP94/01352, filed Apr. 28, 1994.
FIELD OF THE INVENTION
The invention relates to a method for sealing natural or artificially heaped ground sites against an existing or potential gaseous, liquid, radiating and/or solid center of contamination, such as, for example, in the case of abandoned polluted areas (such as abandoned dumping grounds, abandoned locations), waste dumps, pipelines or the like, or also excavated construction sites, using liquid, semiplastic and finely divided sealants or eluates.
BACKGROUND OF THE INVENTION
At the present time, various methods are already known for subsequently encapsulating centers of contamination, particularly disordered garbage dumps, so that the pollutants deposited therein cannot be emitted to the environment.
A method is known from the German Auslegeschrift 3 407 382 for the subsequent underground sealing preferably of dumping grounds. For this method, working pipes are introduced under the waste dump site from a region outside of a waste dump site, without having to drill through the dump site for this purpose. These working pipes are set up below the waste dump from a previously produced vertical shaft produced by a mining method. The sealant is injected from these working pipes with a special apparatus into the soil region. In the case of this method, a very large technical effort is required and the mining procedure for incorporating the working pipes is justifiable only in special cases.
The German Auslegeschrift 34 39 858 discloses that a continuous sealing base is produced with the help of cutting and injection equipment outside of the shielded subterranean curtain surrounding the mass of soil that is to be enclosed by undercutting the latter and is connected tightly with the vertical subterranean curtain. The vertical, supported subterranean curtains, required for this method, once again require a high technical effort and are very expensive.
A further method for the subsequent treatment of waste dumps for protecting the environment is described in the German Auslegeschrift 33 80 897. For this method, the ground surface of the waste dump is divided into immediately adjacent sections. Where the latter are joined, pilot boreholes are made as controlled target boreholes from the starting shafts to the respective opposite draw shafts. Conducting elements are then introduced into these pilot boreholes and their start and end are in opposite starting and draw shafts. In the annular space between the conducting elements, a broaching and injecting apparatus is introduced between the conducting elements and loosens the soil of the sections with a broaching element and prepares it for treatment with a sealant. For this method also, expensive starting and draw shafts are required in order to accommodate the broaching and injection equipment. Moreover, it is not possible to adapt the sealing of the waste dump site to the contours, since the pilot boreholes must run straight for operating the broaching and injection equipment.
From the EP-A-0 317 369, a method for sealing soil sites is known. The known method is an electronic one, for which suitable sealants, such as asphalt or the like, are injected with an electrode, which is subsequently used as injection pipe and, before the sealant is injected, is used to heat the surrounding soil region. The sealant is injected under low pressure through perforation openings introduced in the electrode, so that saturation of the soil takes place.
The technical problem, on which the invention is based, consists of providing a simple method for completely sealing ground sites, particularly centers of contamination such as waste dumps, pipelines or also construction sites, which are still to be excavated, for which method tunnels, flat mining spaces or shafts, produced by mining procedures, are not required.
SUMMARY OF THE INVENTION
This technical problem is solved owing to the fact that a drilling method for producing at least one borehole, the progression of which method is fully controlled, is advanced from the surface outside of the ground site underneath the ground site and that a gaseous, liquid and/or finely divided solid sealant is injected continuously during a longitudinal motion of the drilling head in the borehole into the soil region surrounding the borehole. All forms of introducing the sealant are referred to as injecting in the following.
Due to the drilling method, the progression of which is controlled, all activities can be carried from the surface, so that starting and draw shafts, etc., which are produced by expensive mining procedures, are no longer required.
In this connection, it is particularly advantageous that the boreholes can be adapted, as required, to the contour of the contaminated region for example, as a result of which only a minimum of sealant need be injected into the soil regions. The number and length of the boreholes, required for completely enclosing the center of contamination or the construction site that is still to be excavated, is minimized hereby. Preferably, the drilling diameter for the borehole is up to one meter.
Depending on the soil conditions and on the preliminary investigation of the lower contour of the center of contamination, which investigation either is in existence or still has to be conducted, a safety distance between the boreholes, which have been introduced, and the center of contamination and/or below the lowest points of the investigational boreholes of at least several decimeters is advantageous, in order to achieve absolutely reliable sealing of the center of contamination.
For advancing the boreholes, a known, yet modified, fully controllable, remotely controlled drilling head is used, which enables the boreholes to be advanced in any desired direction and to any desired depth.
The inventive method is particularly simple and efficient, if the sealant is injected continuously into the region of the soil surrounding the borehole during a longitudinal motion of the drill head in the borehole. The injection can take place already while the borehole is being advanced and also when the drilling head or a special broaching device is being retracted towards the inlet opening. The sealant is injected into the soil region through nozzles or outlet openings disposed on the drilling head.
In order to produce a 2-dimensional barrier layer through boreholes, the progression of which is controlled, it is advantageous to bring out the sealant either through at least one lateral nozzle (additional front nozzles are possible) from the rotating drilling strand for producing adjoining to overlapping cylindrical injection sites or, if the drilling strand is not rotating, to bring it out through at least two lateral and/or front nozzles to produce wing-shaped contacting to overlapping injection sites or to have it emerge with a different geometric arrangement of nozzles for the arrangement of injection sites resulting therefrom. The overall objective is to produce barrier layers, which act predominantly horizontally and appear, for example, to be tub-shaped or basin-shaped.
The possibilities for arranging the above-described injection variations are manifold. Advantageously, in the case of non-rotating drilling strands, the injection paths of in each case one borehole, which are produced by at least two injection outlets and lie side by side or above one another, enclose an angle of about 90° to 180°. By these means, percolating water, for example, can run in the thereby formed gutters to the lowest points and be collected and raised in micro-tunnels, which are produced by the same drilling technique and in which filter pipes are installed.
So that the center of contamination is enclosed completely by a barrier layer, it is advantageous to advance a number of boreholes, which are spaced apart and parallel to one another, in the soil. The in each case adjacent regions of a borehole, injected with sealant, should contact one another or intersect a previously produced lamella, that is, a region of soil injected with sealant, so that percolating water can no longer pass through these barrier layers and their overlapping areas into lower layers of soil.
It is also possible to produce such barrier layers next to and underneath the center of contamination, in order to achieve absolutely reliable sealing of the center of contamination. For this purpose, a further number of boreholes is advanced at defined distances from one another at, for example, a vertical angle to the first number of boreholes, which are below the center of contamination, and the sealant once again is injected from these boreholes into the adjacent regions of soil. By these means, two or more, completely closed barrier layers are formed, which surround the center of contamination and ensure absolutely reliably that it is closed off.
In order to achieve reliable sealing of the center of contamination, it is, for example, also possible to advance a network of boreholes, adapted to the contour, underneath the center of contamination, as a result of which the regions of soil, in each case adjacent to a borehole, can be injected several times with sealant. By these means, it is ensured that there are no leaks in the barrier layer formed
In the case of multiple barrier layers, the boreholes of beds, adjacent to one another in the vertical direction, are advanced below the center of contamination parallel to and at a distance from one another at an angle of 20° to 160° to a first number of boreholes of the adjacent plane.
It has been observed that the use of a lignite wax emulsion as a liquid sealant has excellent properties. Likewise, polymeric silicates, resins, different waxes or other chemically-resistant injection media, which remain flexible, also have very advantageous properties.
A barrier layer, formed by injecting, for example, a lignite wax emulsion, is very flexible with respect to subsequent settling of the waste dump site and enables flexural deformability of the barrier layer or layers.
Moreover, the barrier layer, formed by the lignite wax emulsion, is resistant to liquid and gaseous materials, which attack the barrier and are present in the percolating, capillary and subterranean water.
It has been observed that a barrier layer, 30 to 60 cm thick, is completely adequate for achieving reliable sealing.
Moreover, in the case of the inventive method, it is possible to admix further materials or, in the case of a multi-layered construction, to introduce also layers with other injective, absorptive and/or sealing materials, in order to achieve outstanding sealing depending on the soil circumstances. Water glass may be used, as may a cement emulsion in admixture with one of the aforementioned sealants.
The high sliding ability of the lignite wax emulsion is particularly useful in the case of the inventive method, since it also enables other substances to be transported well and, for example, causes very little wear at the nozzles and thus makes a long service life of the drilling head possible.
Depending on the permeability structure of the region surrounding the borehole, it is also possible to inject the sealant pursuant to the invention below the frame structure. The barrier layers to be produced can be adapted in an optimum manner to the soil conditions by low pressure injections.
Depending on the nature of the soil or on the permeating materials to be expected, it is advantageous, in the case of several barrier layers, formed pursuant to the invention in a consecutive or superimposed arrangement, if each of the barrier layers is built up of different sealants or injection materials.
An apparatus for carrying out the method advantageously has nozzles at a fully-controllable, remotely controlled drilling head. These nozzles make it possible to introduce the liquid sealant into the soil region with a sensitive or high pressure up to a distance of 2 to 3 m from the borehole wall.
For example, it is particularly advantageous to dispose a first pair of nozzles opposite a second pair of nozzles offset by 5° to 180° with respect to the longitudinal axis of the drilling head. Each of the pairs of nozzles comprises two opposite nozzles, which in each case are directed so that an angle of 30° to 90° is enclosed in each case with the longitudinal axis of the drilling head. By these means, different geometries of soil regions, with concentrations of the material injected, can be produced.
Advantageously, these nozzles can be surrounded by compressed air outlets, which produce a strong air-induced, preparatory cutting or parallel cutting, which makes it possible to form a sealing jet of any shape, the two-dimensional introduction of the sealant into the soil being preferred. Generally, injections by monophasic to multiphasic methods are possible. Due to the barrier layers, which form, for example, two-dimensional gutters and are disposed below the center of contamination, it is possible to direct the percolating water in particular directions. Of course, cylindrically-interlocking barriers can also be produced.
BRIEF DESCRIPTION OF THE DRAWINGS
Several examples for the further explanation and better understanding of the invention are described and explained in greater detail in the following with reference to the drawings, in which
FIG. 1 shows a diagrammatic representation of a contour-adapted sealing of a waste dump by means of the inventive method,
FIG. 2 shows a diagrammatic representation of the drilling bead as it is advancing a borehole under an abandoned dumping ground,
FIG. 2a shows a diagrammatic representation of the formation of a barrier layer by injecting a sealant as the drilling head is being retracted,
FIG. 3 shows a cross section of a number of boreholes below the waste dump,
FIGS. 4 to 10 in each case show a diagrammatic representation of a cross section of a number of boreholes, for which the arrangement of the boreholes to one another as well as the associated injection regions are constructed differently,
FIG. 11 shows a diagrammatic representation of a front view of a drilling head with nozzles aligned in different directions,
FIG. 12 shows a diagrammatic representation of the side view of the drilling head shown in FIG. 11,
FIG. 13 shows a diagrammatic representation of the progression of the boreholes and of the injection regions for sealing an excavation,
FIG. 14 shows a diagrammatic representation of a cross section of a pipeline with boreholes and injection regions introduced parallel thereto,
FIG. 15 shows a diagrammatic representation of a cross section of a pipeline with a leak, which is sealed by a borehole,
FIG. 16 shows a further diagrammatic representation for completely sealing a pipeline,
FIG. 17 shows a diagrammatic representation of a cross section of a pipeline, which is surrounded with contaminated fragments of a destroyed pipe and is secured by a borehole advanced below and by injections,
FIG. 18 shows a further diagrammatic representation of a cross section of FIG. 17, which is enveloped completely according to the inventive method by boreholes and injections.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 1 to 3, a waste dump site 1 is shaped irregularly in the subterranean part. A number of boreholes 2 are advanced outside of the waste dump site from the surface with known drilling methods, the progression of which is controlled with heed to the contour below the center of contamination and as far as the opposite side of the waste dump site 1.
Starting out from each borehole 2, sealant is injected into the soil regions in each case surrounding a borehole 2, the adjacent regions of a borehole 2 touching or overlapping one another and thus forming a closed barrier layer 3, which runs, with heed to the contour, up to the waste dump site 1.
It can be seen from FIG. 2a that a second barrier 4 is formed underneath the first barrier layer 3 by a network of boreholes 5, which are spaced apart and parallel to one another. The network is turned here through an angle of 90°. Starting out from the boreholes 5, injected regions 4 of soil are formed.
The fully-controllable, remotely controlled drilling head 6 is shown in FIG. 2 as it is moving below the waste dump site 1.
Different arrangements of the boreholes are possible for forming a contour-adapted barrier layer. One example is shown in FIG. 3. The boreholes, parallel to one another and spaced apart, are offset slightly to one another in the vertical direction and the two-dimensional barrier layers 4, starting out in each case from a borehole 2, overlap and form an angle of about 120° with one another.
After the course of the contour of the waste dump site 1 has been investigated accurately by means of maps, previously-taken pictures, geophysical photographs, preliminary drilling, etc., a network of boreholes 2, which extend below the waste dump site 1 with heed to the contour, are advanced with the drilling method, the progression of which is fully controlled. At the same time, or while retracting, the liquid sealant, preferably lignite wax, is injected into the soil regions surrounding in each case a borehole. These soil regions 4, mixed with the liquid sealant, in each case overlap and thus form a closed barrier layer 3, which encloses the waste dump site 1 completely and tightly.
In the case of the inventive method, it is not absolutely necessary to take the boreholes 2 as far as a further opening opposite to the inlet opening. Barrier layers 3 can also be introduced only in partial regions of the soil layer.
Further examples for the arrangement of boreholes, advanced with the inventive method, are shown diagrammatically in FIGS. 4 to 10. In the case of the examples shown, the boreholes, in each case proceed horizontally or also vertically. They can be introduced from the surface to any place desired, in order to seal the soil site
As shown in FIG. 4, a first row of boreholes 2a are superimposed on one another in the soil at equal distances from one another. Offset to this first row of boreholes 2a is a second row of boreholes 2b, which also lie above one another and proceed at the same distances from one another. Extending from each borehole 2a, 2b, there are two slightly expanded injection regions, the injection region starting out from one borehole enclosing an angle of about 130°. Adjacent injection regions in each case overlap. The injection regions, starting out from the first row of boreholes 2a and from the second row of boreholes 2b, in each case intersect so that they form completely enclosed regions, in which, for example, further boreholes 10 are introduced, the progression of which is fully controlled and which serve as monitoring boreholes. This arrangement of boreholes 2a, 2b brings about a sort of double-wall seal.
In the case of the arrangement of boreholes 2a, 2b, 2c shown in FIG. 5, there is introduced between the first row of boreholes 2a and the second row of boreholes 2b a further number of boreholes 2c between these boreholes 2a, 2b. Four individual boreholes of the boreholes 2c extend in each case in the cross section of injection regions, which fan out slightly. These regions in turn intersect in each case the two injection regions emanating from the first row of boreholes 2a and from the second row of boreholes 2b. A very good cross linking of the individual injection regions and, with is that, a very effective sealing of the soil site is ensured hereby.
A further diagrammatic representation of the arrangement of boreholes, similar to the arrangement of the boreholes of FIG. 4, is shown, by way of example, in FIG. 6. Compared to the embodiment of FIG. 4, the individual injection regions extend even further into the ground and overlapping injection regions or injection planes, extending along the individual boreholes 2a, 2b, are formed.
In the case of the example of the arrangement of boreholes 2a, 2b, 2c shown in FIG. 7, a sort of 3-fold wall is formed. For this purpose, a first row of parallel boreholes 2a is formed in the ground. Starting out in each case from a borehole, two injection regions enclose an angle of about 130°. Two injection regions of two adjacent boreholes 2a, approaching one another, cross one another and thus form a first sealing wall. A row of boreholes 2c of similar construction is parallel to and offset from the first row of boreholes 2a. A third row of boreholes 2b with associated injection regions is disposed in mirror image fashion parallel to the second row, as a result of which the injection regions, extending from the individual boreholes 2b, 2c, cross over one another and, in cross section, form a chess board-like arrangement of injection planes. Once again, a reliable sealing of the soil site is ensured.
The construction of the injection regions, shown in FIGS. 4 to 7, arise owing to the fact that, as it is being retracted, the drilling head carries out a rotation and injection material is injected uniformly into the surrounding soil region through different arrangements of nozzles. The diagrammatically shown injection regions are thus, in actual fact, barrier layers or planes, in which the injected material is accumulated and which extend from the boreholes. It is self-evident that the boreholes can be horizontal, vertical or inclined at any angle, since these are introduced starting from the surface and are advanced in a manner, in which their progression is controlled completely, below the soil site that is to be sealed.
In the case of the further examples 8 to 10, further, diagrammatically shown arrangements of boreholes are shown by way of example, for which, however, the drilling head swings back and forth within a specified angular range or rotates constantly about its longitudinal axis.
FIG. 8 shows a cross section of a number of boreholes 2a, 2b, for which, as the drilling head is retracted or also already as the individual boreholes 2a are being advanced, injection material is injected constantly, with rotation of the drilling head, into the surrounding soil region. By these means, columnar injection regions are formed about, in each case, one borehole 2a. The boreholes 2a are at such a distance from one another, that the injection regions of an adjacent borehole in each case overlap. Parallel to this, there are further boreholes 2b, from which individual soil layers extend, in which the injected material is concentrated and which, in turn, intersect the columnar injection regions about the borehole 2a.
For the cross sections of the boreholes, shown diagrammatically in FIGS. 9 and 10, the drilling head 6, as it is being retracted, can swing back and forth through a specified angle. Pairs of nozzles, which cause the injected material to penetrate the region around the borehole to a different depth, are mounted on either side of the drilling head. By these means, two pairs of injected regions are formed in each case in the region of a borehole 2, one pair having a larger radius and the pair, disposed at right angles thereto, having a smaller radius. The boreholes 2 once again are parallel to one another and are at such a distance from one another, that the injected regions of larger radius intersect one another. By these means, once again, effective sealing is achieved, for which the region of soil next to the borehole is also injected absolutely tightly with injection material. For the example shown in FIG. 9, the swiveling angle is about 45° and, for the example shown in FIG. 10, the drilling head is swung back and forth through an angle of about 90° to 100°.
FIGS. 11 and 12 show a diagrammatic representation of the arrangements of the nozzles at the drilling head 6, which is used advantageously for the Examples given FIG. 11 is a front view and shows the nozzles, which are arranged in pairs on opposite sides and have injection angles 15 and 16. FIG. 12 is a side view of the drilling head 6 of FIG. 11, for which the front pair of nozzles is directed slightly forwards and the rear pair of nozzles, turned through 90° with respect to the front pair, is directed slightly towards the rear. FIG. 12 also shows compressed air outlet 101 surrounding one of the outlet nozzles, which optionally can be used to shape jet 102, and further shows an optional front nozzle 103 for producing a jet 110 oriented in the longitudinal direction of the borehole.
FIG. 13 shows a further area of use of the inventive method, for which an excavation is sealed as protection against intrusion of water or infiltration of pollutants. The boreholes 2 are introduced here from a location outside of the intended excavation 25 up to the desired depth. Depending on circumstances, a sealing tub is created by one of the arrangement of boreholes, described, by way of example, above and by injecting the injection material. Since different boreholes 2 can be advanced from the one location with the inventive drilling method, only one change in location of the drilling equipment is required for sealing a diagrammatically shown excavation 25. Starting out from a first location, boreholes 2 are advanced underneath the intended excavation 25 and injection material is injected in each case, so that a sealing tub results. Starting out from a further location, horizontal boreholes 2 are advanced with intersecting injection regions in such a manner with respect to the already produced boreholes, that the soil tub, formed first, is intersected and the soil site or the intended excavation 25 is enveloped tightly. The pit 25 can now be excavated and ground water or pollutant-containing percolated water cannot penetrate into it.
FIGS. 14 to 18 show a further area of use of the inventive drilling method.
FIG. 14 shows a cross section through a pipeline 20 in the soil, which serves, for example, for carrying away pollutant-containing, percolated water. Since these pipelines 20 in many cases are porous and old, subsequent sealing of the soil layers beneath them frequently is necessary. As shown in FIG. 14, a number of boreholes 2, parallel to the pipeline 20, are advanced from the surface for this purpose. While the drilling head is being retracted, injection material is injected uniformly in two-dimensional jets into the surrounding regions of soil. At the same time, the individual boreholes 2 are parallel to one another on a shell surface about the center of the pipeline 20. The injection regions of adjacent boreholes 2 intersect once again. Accordingly, a collection channel is formed beneath the pipeline 20 and collects and carries away the pollutants trickling out in the event of a leak.
FIG. 15 shows a defect 20a in a pipeline 20, through which pollutants trickle into the layers of soil below. This defect can be repaired with the inventive method. For this purpose, a borehole 2 is taken, starting out from the surface, to the located defect 20a and injection materials are injected from the borehole 2 into the soil region in such a manner that these materials extend up to the pipeline 20 and tightly enclose the defect 20a.
FIG. 16 shows a cross section of a pipeline 20, which is surrounded in a lower partial region by two parallel boreholes 2 with injection regions emanating perpendicularly from each borehole 2.
FIGS. 17 and 18 show yet another area of use of the inventive method In many cases, the dimensions of the pipeline 20 for carrying away percolated water are too small and there is therefore a need for pipelines of larger cross section. In a well-known method, the older pipelines are destroyed for this purpose in a "pipe-bursting" or "pipe-eating" method and replaced by larger pipelines. In the case of this known method, however, the problem continues to exist that the fragments 21 of the older pipelines furthermore contain pollutants, which can reach the layers of soil below. To secure these layers below, a borehole 2 is advanced from the surface and injection material is injected into the surrounding regions of soil, so that either, as shown in FIG. 17, a half-shell is formed, which forms a channel for carrying away this percolated water, or, as shown in FIG. 18, several boreholes 2 are advanced, the injection regions of which completely envelope and tightly encapsulate the new pipeline 20 and the fragments 21 of the older pipeline.
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The invention pertains to a process for sealing off ground sites in particular a waste dump, abandoned dumping grounds, pipelines or the like, or also excavated construction sites, using sealants, wherein a fully course-controlled boring technique is used to drive at least one bore underneath the ground site from the surface outside the ground site and the sealant is injected into the soil surrounding the bore. To implement the process, jets for injecting the sealant into the soil are mounted on the steerable remote-controlled boring head.
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BACKGROUND OF THE INVENTION
1. Field of the Invention.
This invention relates to an adjustable weight exercise device used in weight lifting, body building or physical therapy and rehabilitation utilizing auxiliary weights.
2. Description of the Prior Art.
Heretofore attempts to add weight to exercise device have required the keying of one weight to another to interlock them for use such as disclosed in U.S. Pat. No. 5,221,244 ('244) to Doss. This has the disadvantage of requiring the person making the addition to take the time to make sure the weight pieces are interlocked. Also in the '244 patent with the threaded bore of the auxiliary or extra weight there can be a projection that extends beyond the weight that could catch on something or it could cause injury to a person.
In addition, the prior art has included added weights to exercise device such as barbells and dumbbells which are magnetically attached to the device, such as found in U.S. Pat. No. 5,256,121 ('121) to Brotman. Such device has the disadvantage and deficiency of the weights becoming dislodged and falling during use which may cause injury.
SUMMARY OF THE INVENTION
As used throughout the specification and claims "exercise device" shall refer to dumbbells or barbells where each have a center bar for gripping by a hand or hands with a weight juxtaposed each end of the center bar and the exercise device is for lifting.
It is the purpose of the present invention to provide exercise device that is capable of having auxiliary weights added thereto in a quick, convenient and safe manner.
Another object of the present invention is to provide a conventional dumbbell or barbell with a center bar and a pair of disk weights secured on the ends of the center bar, and each weight includes a threaded centrally spaced collar projecting outwardly of the disk to threadably receive auxiliary weights.
A yet further object of the present invention is to provide a set screw to retain the threaded collar to an existing disk weight and center bar for holding an auxiliary weight.
Another object of the present invention is to provide a conventional dumbbell or barbell wherein the added weights are only partially threaded through their thickness so that when positioned on the threaded collar, the collar will not project through the auxiliary weight.
These and other objects and advantages will become apparent from the following part of the specification wherein details have been described for the competence of disclosure, without intending to limit the scope of the invention which is setforth in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
These advantages may be more clearly understood from the following description and by reference to the drawings in which:
FIG. 1 is an exploded view of the adjustable weight exercise device forming a part of the present invention showing that disks of differing weights may be added;
FIG. 2 is a cross sectional elevational view of the present invention showing one end assembled with an auxiliary weight in position, and
FIG. 3 is a front elevational view of the present invention fitted with auxiliary weight disks ready for use.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The drawings illustrate an adjustable weight exercise device generally designated 10 which preferably may be either a barbell or a dumbbell. For the purpose of this application either "barbell" or "dumbbell" shall be interchangeable terms with adjustable weight exercise device.
The device 10 includes a central annular bar 12 that is preferably knurled to assure a proper hand grip for lifting the barbell or dumbbell 10. Each end 14 and 16 of bar 12 is flared outwardly forming annular stops 18 and 20. Each stop includes an annular stop flange 22 and an annular shank portion 24.
Extending inwardly from end 26 (FIG. 2) through the shank 24 into the bar 12 is a thread bore 28, the purpose of which will be described.
Mounted on the shank 24 of each annular stop 18 and 20 are disk weights 30. These are conventional weights that include a center bore 32 and they are preferably annular with rounded annular edges 34. Each disk 30 is equal in weight.
In order to mount the disk weights 30 on the central bar 12, preferably rubber washer 36 (FIG. 1 and 2) is placed over the shank 24 and the weight bore 32 slides over the shank 24 and abuts the washer 36. This will help to lock the weights in place.
Part of the invention resides in the weight locking-holding means or collar designated 44 that abuts the outer face 46 of disks 30. The weight locking-holding means 44 is annular and includes a recess 48 that extends inwardly from outer face 50. It has a tapered inner face 52 as best seen in FIG. 2, and includes a bore 54 that extends through an inner face 56 of the means Optionally, a washer 58 may be placed between the disk weight 30 and the locking holding means 44.
In order to both lock the disk weight 30 to the central bar 12 and to secure the collar 44 to the face 46 of the weight 30 a set screw 60 passes into the collar 44 and is threaded into bore 28 by any conventional means, such as an Allen wrench and Allen opening 62. As can be seen as the screw enters bore 28 it will draw the weight 30 and collar 44 against the stop flange 22 and lock them in place.
Once the locking-holding means or collar 44 is in place auxiliary disk weights 64, 64' or 64" may be inserted. In the preferred embodiment the inventor, when utilizing a dumbbell for one hand exercising, envisions several different disk weights, such but not limited to weights of 2.5, 5, 7.5, 10 and 12.5 pound increments. Such variations will allow a weight lifter or person exercising for therapy to customize the weights to be lifted.
In FIG. 1 there is shown three sizes and poundage of auxiliary disk weights 64 that may be used to accomplish the desired weight for lifting. In other words the person could start with the dumbbell 10 of FIG. 1 and add the increased auxiliary weights 64 to the desired amount.
With the present invention, the adjustment of weight or the dumbbell or barbell 12 can be interchanged or added with relative ease.
The collar 44 is externally threaded, as best seen in FIGS. 1 and 2.
The auxiliary disk weights 64, etc. are generally of the same configuration as weights 30 except their diameters are different depending upon the specific pounds of each disk weights 64.
The weights 64, 64' etc. each include a central thread bore 66 that extends inward from face 68, but does not extend through the thickness of the disk 64. The bore terminates in an end wall 70. Preferably the bore 66 is fitted with a lock washer 72.
In order to attach auxiliary disk weights 64, 64 or 64" or other weights, it is threaded onto the threaded collar 44 and is cinched up against the washer 58 to assure a tight fit that will not easily be dislodged. The weights 64 are placed on both ends and a new weight reading is available for body building or therapy.
It should be noted that if the exercise device 10 is a barbell then the central bar 12 would be longer and the disk weights could vary in poundage and dimension. However, the same principle is available for customizing the weights thereof as with a dumbbell.
With the auxiliary weights 64' etc. having limited entrance onto the collar 44, it will not protrude from the auxiliary disk weights outer face 72, see FIG. 2 to injure anyone that might hit the auxiliary disk weight 64.
In addition, each of the disk weights 64, 64', 64" may have bores 74 for hanging the disk weights on a rack (not shown) when not in use.
Further, in order to protect the disk weights 30 and 64 or any of the outer auxiliary weights 64, etc. and to help deaden the sound if dropped, they may be coated with latex rubber or other plastic substances.
The invention and its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangements of the parts without departing from the spirit and scope thereof or sacrificing its material advantages, arrangements herein before described being merely by way of example. I do not wish to be restricted to the specific forms shown or uses mentioned, except as defined in the accompanying claims, wherein various portions have been separated for clarity of reading and not for emphasis.
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A body building or therapy adjustable weight exercise device for use in strengthening hands, arms, chests and neck of a person using the same, wherein it is either a barbell or dumbbell including a central bar section to be gripped by a hand or hands with equal poundage weights at each end of the bar, and weights holding-locking means to affix the weights to the central bar and auxiliary disk weights capable of being removably mounted on the holding-locking means to alter the total weight of the device.
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BACKGROUND OF THE INVENTION
1. Technical Field
The invention relates generally to polypropylene and materials or articles made from polypropylene.
2. Background of the Art
Polypropylene is used for a variety of different products or applications. These may include films, fibers or molded articles. Polypropylene used in such materials or articles is usually produced as an isotactic propylene polymer, which is a stereospecific polymer.
Stereospecific polymers are polymers that have a defined arrangement of molecules in space. Both isotactic and syndiotactic propylene polymers are stereospecific. Isotactic polypropylene is characterized by having all the pendant methyl groups oriented either above or below the polymer chain or backbone. Isotactic polypropylene can be illustrated by the following general chemical formula:
Syndiotactic propylene polymers are those in which the methyl groups attached to the tertiary carbon atoms of successive monomeric units in the polymer chain lie on alternate sides of the plane of the polymer. Syndiotactic polypropylene can be illustrated by the following general structural formula:
While both syndiotactic and isotactic polypropylene are semi-crystalline polymers, however, they each have different characteristics or properties.
Conventional polypropylene is usually prepared as an isotactic polymer from Ziegler-Natta polymer catalysts. The Ziegler-Natta catalysts produce a highly isotactic polypropylene that is easily processed and useful in preparing a wide variety of articles or products.
In certain applications, it is necessary that the polypropylene materials be sterilized. This is particularly true for materials used in medical and food handling and sterilization applications. One method of sterilizing such materials is through the use of high-energy radiation. Both gamma radiation and electron-beam (E-beam) radiation are commonly used for irradiating and sterilizing many materials and articles. While exposure to such radiation is effective in sterilizing such materials, the radiation may also have an effect on the material itself. In many cases, these effects are undesirable.
With respect to isotactic polypropylene prepared from conventional Ziegler-Natta catalysts, for example, exposure of the polypropylene to high-energy radiation can result in a degradation of the polymer. The polypropylene will often become brittle and may be discolored, turning to a light or deep yellow. Such changes in the polymer usually do not occur immediately after irradiation, but may occur slowly, appearing sometime later after sterilization.
The mechanism by which such degradation of polypropylene occurs is believed to be, without being limited to any one particular theory, an auto-oxidative reaction in which free radicals are formed that react with oxygen, usually from air, and which results in the degradation of the polymer. The reaction steps can be represented as follows:
R→R. (1)
R.+O2→RO2. (2)
RO2.+RH→ROOH+R. (3)
RO2.+R.→ROOR (4)
RO2.+RO2.→ROOR+O2 (5)
R.+R.→R−R (6)
where R is the irradiated polypropylene chain, and R. is the alkyl radical formed during irradiation. The alkyl radical R. is regenerated in equation 3 and each alkyl radical formed will consume numerous molecules of oxygen unless such radicals are terminated earlier as shown in equations 4-6.
As discussed earlier, degradation effects are usually seen over time. This may be a result, at least in part, due to slower radical migration from within the crystalline regions of the polymer towards the surface to react with ambient oxygen. Thus, polymer degradation may occur over time as a result of this radical migration. Polypropylene articles having high surface areas per unit volume will usually tend to degrade much faster than those having low surface areas per unit volume.
SUMMARY OF THE INVENTION
n one aspect, the invention is a polymer material including a blend of an isotactic propylene polymer and a syndiotactic propylene polymer wherein the isotactic propylene polymer has a molecular weight distribution (Mw/Mn) of 4.0 or less and a xylene solubles of 2 percent or less, and wherein the polymer material provides a SMS fabric material having a 50% or greater retention of machine direction elongation strength at a radiation dose of 3-5 Mrads.
In another aspect, the invention is a fabric including a network of fibers prepared using a polymer material including a blend of an isotactic propylene polymer and a syndiotactic propylene polymer wherein the isotactic propylene polymer has a molecular weight distribution (Mw/Mn) of 4.0 or less and a xylene solubles of 2 percent or less, and wherein the isotactic propylene polymer provides a SMS fabric material having a 50% or greater retention of machine direction elongation strength at a radiation dose of 3-5 Mrads.
In still another aspect, the invention is a fabric material in which at least two layers of fabric are laminated together wherein the layers of fabric include a network of fibers prepared using a polymer material including a blend of an isotactic propylene polymer and a syndiotactic propylene polymer wherein the isotactic propylene polymer has a molecular weight distribution (Mw/Mn) of 4.0 or less and a xylene solubles of 2 percent or less, and wherein the isotactic propylene polymer provides a SMS fabric material having a 50% or greater retention of machine direction elongation strength at a radiation dose of 3-5 Mrads.
Another embodiment of the invention is an article formed from a polymer material including a blend of an isotactic propylene polymer and a syndiotactic propylene polymer wherein the isotactic propylene polymer has a molecular weight distribution (Mw/Mn) of 4.0 or less and a xylene solubles of 2 percent or less, and wherein the isotactic propylene polymer provides a SMS fabric material having a 50% or greater retention of machine direction elongation strength at a radiation dose of 3-5 Mrads. The article is selected from a group consisting of diapers, incontinence products, sanitary towels, tampons, feminine hygiene pads, protective clothing, work clothing, disposable clothing, gowns, masks, insulating material, headwear, overshoes, flannels, bandages, bedcloths, wipes, syringes, tongue depressors, vacuum cleaner bags, tea bags, coffee filters, book covers, carpet underlay, wall coverings, bedclothes, table cloths, covers, mattress filing, covering material, furniture fabrics, cushion covers, upholstery, wadding, filters, air filters, gas filters, water filters, oil adsorbent materials, sanding material, cable sheaths, insulation tape, reinforcements, insulation, roof sealing, geotextile material, capillary mats, covering material for crop forcing, covering material for seedling protection, greenhouse shielding, packaging material, packaging material for fruits or vegetables, insulation material for automobiles, roof linings, battery separators and coating carriers, luggage, handbags, sacks, carrier bags, bags, self-adhesive materials, tents, cheese wrappers, artist's canvas and advertising articles.
DETAILED DESCRIPTION OF THE INVENTION
It has been found that addition of amounts of syndiotactic polypropylene as a blend with isotactic polypropylene, which may be either Ziegler-Natta or metallocene-catalyzed isotactic polypropylene, can increase the polymer's radiation resistance or reduce degradation of the polymer from radiation when compared to the same polymer without any syndiotactic polypropylene. These materials may show as much as 70%, 80% or even 90% retention in strength properties after exposure to high energy radiation dependent upon the dosage of radiation, the presence or absence of oxygen, and the use of antioxidants and mobilizing additives such as mineral oil.
The metallocene catalyst systems used with the invention may be selected from those useful for olefin preparation. Such metallocene catalyst systems may be characterized generally as coordination compounds incorporating one or more cyclopentadienyl (Cp) groups (which may be substituted or unsubstituted, each substitution being the same or different) coordinated with a transition metal through pi (or π) bonding.
The Cp substituent groups may be linear, branched or cyclic hydrocarbyl radicals. The cyclic hydrocarbyl radicals may further form other contiguous ring structures, including, for example indenyl, azulenyl and fluorenyl groups. These additional ring structures may also be substituted or unsubstituted by hydrocarbyl radicals, such as C 1 to C 20 hydrocarbyl radicals.
A specific example of a metallocene catalyst is a bulky ligand metallocene compound generally represented by the formula:
[L] m M[A] n
where L is a bulky ligand, A is a leaving group, M is a transition metal and m and n are such that the total ligand valency corresponds to the transition metal valency. For example, when the valence of M is 4, m may be from 1 to 3 and n may be from 1 to 3 and n+m=4.
The metal atom “M” of the metallocene catalyst compound, as described throughout the specification and claims, may be selected from Groups 3 through 12 atoms and lanthanide group atoms in one embodiment; and selected from Groups 3 through 10 atoms in a more particular embodiment, and selected from Sc, Ti, Zr, Hf, V, Nb, Ta, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, and Ni in yet a more particular embodiment; and selected from Groups 4, 5 and 6 atoms in yet a more particular embodiment, and Ti, Zr, Hf atoms in yet a more particular embodiment, and Zr in yet a more particular embodiment. The oxidation state of the metal atom “M” may range from 0 to +7 in one embodiment; and in a more particular embodiment, is +1, +2, +3, +4 or +5; and in yet a more particular embodiment is +2, +3 or +4.
The bulky ligand generally includes a cyclopentadienyl group (Cp) or a derivative thereof. The Cp ligand(s) form at least one chemical bond with the metal atom M to form the “metallocene catalyst compound”. The Cp ligands are distinct from the leaving groups bound to the catalyst compound in that they are not highly susceptible to substitution/abstraction reactions.
The Cp group typically includes ring, fused ring(s) and/or substituted ring or fused ring systems. The ring(s) or ring system(s) typically include atoms selected from group 13 to 16 atoms, for example, carbon, nitrogen, oxygen, silicon, sulfur, phosphorous, germanium, boron, aluminum and combinations thereof, wherein carbon makes up at least 50% of the ring members. Non-limiting examples include cyclopentadienyl, cyclopentaphenanthreneyl, indenyl, 4,5-benzindenyl, 4,5-bis-benzindenyl, fluorenyl, cyclooctatetraenyl, cyclopentacyclododecene, phenanthrindenyl, 3,4-benzofluorenyl, 9-phenylfluorenyl, 8-H-cyclopent[a]acenaphthylenyl, 7-H-dibenzofluorenyl, indeno[1,2-9]anthrene, thiophenoindenyl, thiophenofluorenyl, hydrogenated versions thereof (e.g., 4,5,6,7-tetrahydroindenyl, or “H 4 Ind”), substituted versions thereof, and heterocyclic versions thereof.
Cp substituent groups may include hydrogen radicals, alkyls, alkenyls, alkynyls, cycloalkyls, aryls, acyls, aroyls, alkoxys, aryloxys, alkylthiols, dialkylamines, alkylamidos, alkoxycarbonyls, aryloxycarbonyls, carbomoyls, alkyl- and dialkyl-carbamoyls, acyloxys, acylaminos, aroylaminos, and combinations thereof. More particular non-limiting examples of alkyl substituents include methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, benzyl, phenyl, methylphenyl, and tert-butylphenyl groups and the like, including all their isomers, for example tertiary-butyl, isopropyl, and the like. Other possible radicals include substituted alkyls and aryls, optionally containing halogens such as, for example, fluoromethyl, fluoroethyl, difluoroethyl, iodopropyl, bromohexyl, chlorobenzyl and hydrocarbyl substituted organometalloid radicals including trimethylsilyl, trimethylgermyl, methyldiethylsilyl and the like; and halocarbyl-substituted organometalloid radicals including tris(trifluoromethyl)silyl, methylbis(difluoromethyl)silyl, bromomethyldimethylgermyl and the like; and disubstituted boron radicals including dimethylboron for example; and disubstituted Group 15 radicals including dimethylamine, dimethylphosphine, diphenylamine, methylphenylphosphine, Group 16 radicals including methoxy, ethoxy, propoxy, phenoxy, methylsulfide and ethylsulfide. Other substituents R include olefins such as but not limited to olefinically unsaturated substituents including vinyl-terminated ligands, for example 3-butenyl, 2-propenyl, 5-hexenyl and the like. In one embodiment, at least two R groups are joined to form a ring structure having from 3 to 30 atoms selected from the group consisting of carbon, nitrogen, oxygen, phosphorous, silicon, germanium, aluminum, boron and combinations thereof. Also, a substituent group R group such as 1-butanyl may form a bonding association to the element M.
Each anionic leaving group is independently selected and may include any leaving group, such as halogen ions, hydrides, C 1 to C 12 alkyls, C 2 to C 12 alkenyls, C 6 to C 12 aryls, C 7 to C 20 alkylaryls, C 1 to C 12 alkoxys, C 6 to C 16 aryloxys, C 7 to C 18 alkylaryloxys, C 1 to C 12 fluoroalkyls, C 6 to C 12 fluoroaryls, and C 1 to C 12 heteroatom-containing hydrocarbons and substituted derivatives thereof; hydride, halogen ions, C 1 to C 6 alkylcarboxylates, C 1 to C 6 fluorinated alkylcarboxylates, C 6 to C 12 arylcarboxylates, C 7 to C 18 alkylarylcarboxylates, C 1 to C 6 fluoroalkyls, C 2 to C 6 fluoroalkenyls, and C 7 to C 18 fluoroalkylaryls in yet a more particular embodiment; hydride, chloride, fluoride, methyl, phenyl, phenoxy, benzoxy, tosyl, fluoromethyls and fluorophenyls in yet a more particular embodiment; C 1 to C 12 alkyls, C 2 to C 12 alkenyls, C 6 to C 12 aryls, C 7 to C 20 alkylaryls, substituted C 1 to C 12 alkyls, substituted C 6 to C 12 aryls, substituted C 7 to C 20 alkylaryls and C 1 to C 12 heteroatom-containing alkyls, C 1 to C 12 heteroatom-containing aryls and C 1 to C 12 heteroatom-containing alkylaryls in yet a more particular embodiment; chloride, fluoride, C 1 to C 6 alkyls, C 2 to C 6 alkenyls, C 7 to C 18 alkylaryls, halogenated C 1 to C 6 alkyls, halogenated C 2 to C 6 alkenyls, and halogenated C 7 to C 18 alkylaryls in yet a more particular embodiment; fluoride, methyl, ethyl, propyl, phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, fluoromethyls (mono-, di- and trifluoromethyls) and fluorophenyls (mono-, di-, tri-, tetra- and pentafluorophenyls) in yet a more particular embodiment; and fluoride in yet a more particular embodiment.
Other non-limiting examples of leaving groups include amines, phosphines, ethers, carboxylates, dienes, hydrocarbon radicals having from 1 to 20 carbon atoms, fluorinated hydrocarbon radicals (e.g., —C 6 F 5 (pentafluorophenyl)), fluorinated alkylcarboxylates (e.g., CF 3 C(O)O − ), hydrides and halogen ions and combinations thereof. Other examples of leaving groups include alkyl groups such as cyclobutyl, cyclohexyl, methyl, heptyl, tolyl, trifluoromethyl, tetramethylene, pentamethylene, methylidene, methyoxy, ethyoxy, propoxy, phenoxy, bis(N-methylanilide), dimethylamide, dimethylphosphide radicals and the like. In one embodiment, two or more leaving groups form a part of a fused ring or ring system.
L and A may be bridged to one another. In catalysts where there are two L groups, they may be bridged to each other. A bridged metallocene, for example may, be described by the general formula:
XCp A Cp B MA n
wherein X is a structural bridge, CP A and CP B each denote a cyclopentadienyl group, each being the same or different and which may be either substituted or unsubstituted, M is a transition metal and A is an alkyl, hydrocarbyl or halogen group and n is an integer between 0 and 4, and either 1 or 2 in a particular embodiment.
Non-limiting examples of bridging groups (X) include divalent hydrocarbon groups containing at least one Group 13 to 16 atom, such as but not limited to at least one of a carbon, oxygen, nitrogen, silicon, aluminum, boron, germanium and tin atom and combinations thereof; wherein the heteroatom may also be C 1 to C 12 alkyl or aryl substituted to satisfy neutral valency. The bridging group may also contain substituent groups as defined above including halogen radicals and iron. More particular non-limiting examples of bridging groups are represented by C 1 to C 20 alkylenes, substituted C 1 to C 6 alkylenes, oxygen, sulfur, R 2 C═, R 2 Si═, —Si(R) 2 Si(R 2 )—, R 2 Ge═, RP═ (wherein “═” represents two chemical bonds), where R is independently selected from the group hydride, hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, hydrocarbyl-substituted organometalloid, halocarbyl-substituted organometalloid, disubstituted boron, disubstituted Group 15 atoms, substituted Group 16 atoms, and halogen radical; and wherein two or more Rs may be joined to form a ring or ring system. In one embodiment, the bridged metallocene catalyst component has two or more bridging groups (X).
Other non-limiting examples of bridging groups include methylene, ethylene, ethylidene, propylidene, isopropylidene, diphenylmethylene, 1,2-dimethylethylene, 1,2-diphenylethylene, 1,1,2,2-tetramethylethylene, dimethylsilyl, diethylsilyl, methyl-ethylsilyl, trifluoromethylbutylsilyl, bis(trifluoromethyl)silyl, di(n-butyl)silyl, di(n-propyl)silyl, di(i-propyl)silyl, di(n-hexyl)silyl, dicyclohexylsilyl, diphenylsilyl, cyclohexylphenylsilyl, t-butylcyclohexylsilyl, di(t-butylphenyl)silyl, di(p-tolyl)silyl and the corresponding moieties, wherein the Si atom is replaced by a Ge or a C atom; dimethylsilyl, diethylsilyl, dimethylgermyl and/or diethylgermyl. The bridging groups may also have carbons or silicons having an olefinic substituent.
In another exemplary catalyst, the bridging group may also be cyclic, and include 4 to 10 ring members or 5 to 7 ring members in a more particular embodiment. The ring members may be selected from the elements mentioned above, and/or from one or more of B, C, Si, Ge, N and O in a particular embodiment. Non-limiting examples of ring structures which may be present as or part of the bridging moiety are cyclobutylidene, cyclopentylidene, cyclohexylidene, cycloheptylidene, cyclooctylidene and the corresponding rings where one or two carbon atoms are replaced by at least one of Si, Ge, N and O, in particular, Si and Ge. The bonding arrangement between the ring and the Cp groups may be cis-, trans-, or a combination thereof.
The cyclic bridging groups may be saturated or unsaturated and/or carry one or more substituents and/or be fused to one or more other ring structures. If present, the one or more substituents are selected from the group hydrocarbyl (e.g., alkyl such as methyl) and halogen (e.g., F, Cl) in one embodiment. The one or more Cp groups which the above cyclic bridging moieties may optionally be fused to may be saturated or unsaturated and are selected from the group of those having 4 to 10 ring members, more particularly 5, 6 or 7 ring members (selected from the group of C, N, O and S in a particular embodiment) such as, for example, cyclopentyl, cyclohexyl and phenyl. Moreover, these ring structures may themselves be fused such as, for example, in the case of a naphthyl group. Moreover, these (optionally fused) ring structures may carry one or more substituents. Illustrative, non-limiting examples of these substituents are hydrocarbyl (particularly alkyl) groups and halogen atoms.
The metallocene catalysts also include the CpFlu family of catalysts (e.g., a metallocene incorporating a substituted or unsubstituted Cp fluorenyl ligand structure) represented by the following formula:
X(CpR 1 n R 2 m )(FluR 3 p )
wherein Cp is a cyclopentadienyl group; Flu is a fluorenyl group; X is a structural bridge between Cp and Flu; R 1 is a substituent on the Cp; n is 0, 1, or 2; R 2 is a substituent on the Cp at carbons 3 or 4 (a position which is proximal to the bridge); m is 0, 1, or 2; each R 3 is the same or different and is a hydrogen or a hydrocarbyl group having from 1 to 20 carbon atoms with R 3 being substituted at carbons 2, 3, 4, 5, 6, or 7 (a nonproximal position on the fluorenyl group) and at least one other R 3 , if present, being substituted at an opposed position on the fluorenyl group; and p is 0, 1, 2, 3, or 4.
Exemplary CpFlu molecules include those having a general structure such as:
wherein M is a metal, the X in this embodiment is a methylene structural bridge. Note that all rings are aromatic notwithstanding the placement of the double bonds in the general structure.
The bis-indenyl metallocene catalysts are also useful in olefin polymerization. A bridged metallocene, the bis-indenyls may be described by the general formula:
XCp A Cp B MA n
wherein X, M and A are as described above, but Cp A and Cp B each denote an indenyl group. These catalysts have been reported to be particularly useful for production of isotactic polypropylene in U.S. Pat. No. 6,414,095, the contents of which are incorporated herein by reference.
Exemplary bis-indenyl molecules include those having a general structure such as:
wherein M is a metal, and the X in this embodiment is a methylene structural bridge.
Another family of the metallocene catalyst includes bridged mono-ligand metallocene compounds (e.g., mono cyclopentadienyl catalyst components). In this embodiment, the at least one metallocene catalyst component is a bridged “half-sandwich” metallocene catalyst. In yet another aspect of the invention, the at least one metallocene catalyst component is an unbridged “half sandwich” metallocene.
Described another way, the “half sandwich” metallocenes above are described in U.S. Pat. No. 6,069,213, U.S. Pat. No. 5,026,798, U.S. Pat. No. 5,703,187, and U.S. Pat. No. 5,747,406, including a dimer or oligomeric structure, such as disclosed in, for example, U.S. Pat. No. 5,026,798 and U.S. Pat. No. 6,069,213, which are incorporated by reference herein.
The metallocenes may be present as racemic or meso compositions. In some embodiments, the metallocene compositions may be predominantly racemic. In other applications, the metallocenes may be predominantly meso.
Non-limiting examples of metallocene catalyst components include:
cyclopentadienylzirconiumA n , indenylzirconiumA n , (1-methylindenyl)zirconiumA n , (2-methylindenyl)zirconiumA n , (1-propylindenyl)zirconiumA n , (2-propylindenyl)zirconiumA n , (1-butylindenyl)zirconiumA n , (2-butylindenyl)zirconiumA n , methylcyclopentadienylzirconiumA n , tetrahydroindenylzirconiumA n , pentamethylcyclopentadienylzirconiumA n , cyclopentadienylzirconiumA n , pentamethylcyclopentadienyltitaniumA n , tetramethylcyclopentyltitaniumA n , (1,2,4-trimethylcyclopentadienyl)zirconiumA n , dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(cyclopentadienyl)zirconiumA n , dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(1,2,3-trimethylcyclopentadienyl)zirconiumA n , dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(1,2-dimethylcyclopentadienyl)zirconiumA n , dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(2-methylcyclopentadienyl)zirconiumA n , dimethylsilylcyclopentadienylindenylzirconiumA n , dimethylsilyl(2-methylindenyi)(9-fluorenyl)zirconiumA n , diphenylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(3-propylcyclopentadienyl)zirconiumA n , dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(3-t-butylcyclopentadienyl)zirconiumA n , dimethylgermyl(1,2-dimethylcyclopentadienyl)(3-isopropylcyclopentadienyl)zirconiumA n , dimethylsilyl(1,2,3,4-tetramethylcyclopentadienyl)(3-methylcyclopentadienyl)zirconiumA n , diphenylmethylidene(cyclopentadienyl)(9-fiuorenyl)zirconiumA n , diphenylmethylidenecyclopentadienylindenylzirconiumA n , isopropylidenebiscyclopentadienylzirconiumA n , isopropylidene(cyclopentadienyl)(9-fluorenyl)zirconiumA n , isopropylidene(3-methylcyclopentadienyl)(9-fluorenyl)zirconiumA n , ethylenebis(9-fluorenyl)zirconiumA n , ethylenebis(1-indenyl)zirconiumA n , ethylenebis(2-methyl-1-indenyl)zirconiumA n , ethylenebis(2-propyl-4,5,6,7-tetrahydro-1-indenyl)zirconiumA n , ethylenebis(2-isopropyl-4,5,6,7-tetrahydro-1-indenyl)zirconiumA n , ethylenebis(2-butyl-4,5,6,7-tetrahydro-1-indenyl)zirconiumA n , ethylenebis(2-isobutyl-4,5,6,7-tetrahydro-1-indenyl)zirconiumA n , dimethylsilyl(4,5,6,7-tetrahydro-1-indenyl)zirconiumA n , diphenyl(4,5,6,7-tetrahydro-1-indenyl)zirconiumA n , ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconiumA n , dimethylsilylbis(cyclopentadienyl)zirconiumA n , dimethylsilylbis(9-fluorenyl)zirconiumA n , dimethylsilylbis(1-indenyl)zirconiumA n , dimethylsilylbis(2-methylindenyl)zirconiumA n , dimethylsilylbis(2-propylindenyi)zirconiumA n , dimethylsilylbis(2-butylindenyl)zirconiumA n , diphenylsilylbis(2-methylindenyl)zirconiumA n , diphenylsilylbis(2-propylindenyl)zirconiumA n , diphenylsilylbis(2-butylindenyl)zirconiumA n , dimethylgermylbis(2-methylindenyl)zirconiumA n , dimethylsilylbistetrahydroindenylzirconiumA n , dimethylsilylbistetramethylcyclopentadienylzirconiumA n , dimethylsilyi(cyclopentadienyl)(9-fluorenyl)zirconiumA n , diphenylsilyi(cyclopentadienyl)(9-fluorenyi)zirconiumA n , diphenylsilylbisindenylzirconiumA n , cyclotrimethylenesilyltetramethylcyclopentadienylcyclopentadienylzirconiumA n , cyclotetramethylenesilyltetramethylcyclopentadienylcyclopentadienylzirconiumA n , cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(2-methylindenyl)zirconiumA n , cyclotrimethylenesilyl(tetramethylcyclopentadienyl)(3-methylcyclopentadienyl)zirconiumA n , cyclotrimethylenesilylbis(2-methylindenyl)zirconiumA n , cyclotrimethylenesilyl(tetramethylcyclopentadienyl) (2,3,5-trimethylclopentadienyl)zirconiumA n , cyclotrimethylenesilylbis(tetramethylcyclopentadienyl)zirconiumA n , dimethylsilyl(tetramethylcyclopentadieneyl)(N-tertbutylamido)titaniumA n , biscyclopentadienylchromiumA n , biscyclopentadienylzirconiumA n , bis(n-butylcyclopentadienyl)zirconiumA n , bis(n-dodecycicyclopentadienyl)zirconiumA n , bisethylcyclopentadienylzirconiumA n , bisisobutylcyclopentadienylzirconiumA n , bisisopropylcyclopentadienylzirconiumA n , bismethylcyclopentadienylzirconiumA n , bis(n-oxtylcyclopentadienyl)zirconiumA n , bis(n-pentylcyclopentadienyl)zirconiumA n , bis(n-propylcyclopentadienyl)zirconiumA n , bis(trimethylsilylcyclopentadienyl)zirconiumA n , bis(1,3-bis(trimethylsilyl)cyclopentadienyl)zirconiumA n , bis(1-ethyl-2-methylcyclopentadienyl)zirconiumA n , bis(1-ethyl-3-methylcyclopentadienyl)zirconiumA n , bispentamethylcyclopentadienylzirconiumA n , bispentamethylcyclopentadienylzirconiumA n , bis(1-propyl-3-methylcyclopentadienyl)zirconiumA n , bis(1-n-butyl-3-methylcyclopentadienyl)zirconiumA n , bis(1-isobutyl-3-methylcyclopentadienyl)zirconiumA n , bis(1-propyl-3-butylcyclopentadienyl)zirconiumA n , bis(1,3-n-butylcyclopentadienyl)zirconiumA n , bis(4,7-dimethylindenyl)zirconiumA n , bisindenylzirconiumA n , bis(2-methylindenyl)zirconiumA n , cyclopentadienylindenylzirconiumA n , bis(n-propylcyclopentadienyl)hafniumA n , bis(n-butylcyclopentadienyl)hafniumA n , bis(n-pentylcyclopentadienyl)hafniumA n , (n-propylcyclopentadienyl)(n-butylcyclopentadienyl)hafniumA n , bis[(2-trimethylsilyiethyl)cyclopentadienyl]hafniumA n , bis(trimethylsilylcyclopentadienyl)hafniumA n , bis(2-n-propylindenyl)hafniumA n , bis(2-n-butylindenyl)hafniumA n , dimethylsilylbis(n-propylcyclopentadienyl)hafniumA n , dimethylsilylbis(n-butylcyclopentadienyl)hafniumA n , bis(9-n-propylfluorenyl)hafniumA n , bis(9-n-butylfluorenyl)hafniumA n , (9-n-propylfluorenyl)(2-n-propylindenyl)hafniumA n , bis(1-n-propyl-2-methylcyclopentadienyl)hafniumA n , (n-propylcyclopentadienyl)(1-n-propyl-3-n-butylcyclopentadienyl)hafniumA n , dimethylsilyltetramethylcyclopentadienylcyclopropylamidotitaniumA n , dimethylsilyltetramethylcyclopentadienylcyclobutylamidotitaniumA n , dimethylsilyltetramethylcyclopentadienylcyclopentylamidotitaniumA n , dimethylsilyltetramethylcyclopentadienylcyclohexylamidotitaniumA n , dimethylsilyltetramethylcyclopentadienylcycloheptylamidotitaniumA n , dimethylsilyltetramethylcyclopentadienylcyclooctylamidotitaniumA n , dimethylsilyltetramethylcyclopentadienylcyclononylamidotitaniumA n , dimethylsilyltetramethylcyclopentadienylcyclodecylamidotitaniumA n , dimethylsilyltetramethylcyclopentadienylcycioundecylamidotitaniumA n , dimethylsilyltetramethylcyclopentadienylcyclododecylamidotitaniumA n , dimethylsilyltetramethylcyclopentadienyl(sec-butylamido)titaniumA n , dimethylsilyl(tetramethylcyclopentadienyl)(n-octylamido)titaniumA n , dimethylsilyl(tetramethylcyclopentadienyl)(n-decylamido)titaniumA n , dimethylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titaniumA n , methylphenylsilyltetramethylcyclopentadienylcyclopropylamidotitaniumA n , methylphenylsilyltetramethylcyclopentadienylcyclobutylamidotitaniumA n , methylphenylsilyltetramethylcyclopentadienylcyclopentylamidotitaniumA n , methylphenylsilyltetramethylcyclopentadienylcyclohexylamidotitaniumA n , methylphenylsilyltetramethylcyclopentadienylcycloheptylamidotitaniumA n , methylphenylsilyltetramethylcyclopentadienylcyclooctylamidotitaniumA n , methylphenylsilyltetramethylcyclopentadienylcyclononylamidotitaniumA n , methylphenylsilyltetramethylcyclopentadienylcyclodecylamidotitaniumA n , methylphenylsilyltetramethylcyclopentadienylcycloundecylamidotitaniumA n , methylphenylsilyltetramethylcyclopentadienylcyclododecylamidotitaniumA n , methylphenylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)titaniumA n , methylphenylsilyl(tetramethylcyclopentadienyl)(n-octylamido)titaniuman, methylphenylsilyl(tetramethylcyclopentadienyl)(n-decylamido)titaniuman, methylphenylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titaniumA n , diphenylsilyltetramethylcyclopentadienylcyclopropylamidotitaniumA n , diphenylsilyltetramethylcyclopentadienylcyclobutylamidotitaniumA n , diphenylsilyltetramethylcyclopentadienylcyclopentylamidotitaniumA n , diphenylsilyltetramethylcyclopentadienylcyclohexylamidotitaniumA n , diphenylsilyltetramethylcyclopentadienylcycloheptylamidotitaniumA n , diphenylsilyltetramethylcyclopentadienylcyclooctylamidotitaniumA n , diphenylsilyltetramethylcyclopentadienylcyclononylamidotitaniumA n , diphenylsilyltetramethylcyclopentadienylcyclodecylamidotitaniumA n , diphenylsilyltetramethylcyclopentadienylcycloundecylamidotitaniumA n , diphenylsilyltetramethylcyclopentadienylcyclododecylamidotitaniumA n , diphenylsilyl(tetramethylcyclopentadienyl)(sec-butylamido)titaniumanA n , diphenylsilyl(tetramethylcyclopentadienyl)(n-octylamido)titaniumA n , diphenylsilyl(tetramethylcyclopentadienyl)(n-decylamido)titaniumA n , diphenylsilyl(tetramethylcyclopentadienyl)(n-octadecylamido)titaniumA n , and derivatives thereof.
As used herein, the term “metallocene activator” is defined to be any compound or combination of compounds, supported or unsupported, which may activate a single-site catalyst precursor compound (e.g., metallocenes, Group 15 containing catalysts, etc) to form the metallocene catalyst system. Typically, this involves the abstraction of at least one leaving group (A group in the formulas/structures above, for example) from the metal center of the catalyst component. The catalyst components of the present invention are thus activated towards olefin polymerization using such activators. Embodiments of such activators include Lewis acids such as cyclic or oligomeric polyhydrocarbylaluminum oxides and so called non-coordinating ionic activators (“NCA”), alternately, “ionizing activators” or “stoichiometric activators”, or any other compound that may convert a neutral metallocene catalyst component to a metallocene cation that is active with respect to olefin polymerization.
More particularly, it is within the scope of this invention to use Lewis acids such as the aluminoxanes as activators. Aluminoxanes are well known in the art and can be made by conventional methods, such as, for example admixing an aluminum alkyl with water. Nonhydrolytic routes to form these materials are also known. Traditionally, the most widely used aluminoxane is methylaluminoxane (MAO), an aluminoxane compound in which the alkyl groups are methyls. Aluminoxanes with higher alkyl groups include hexaisobutylalumoxane (HIBAO) isobutylaluminoxane, ethylaluminoxane, butylaluminoxane, heptylaluminoxane and methylbutylaluminoxane; and combinations thereof. Modified aluminoxanes (e.g., “MMAO”), may also be used. The use of MAO and other aluminum-based activators in polyolefin polymerizations as activators are well known in the art.
Ionizing activators are well known in the art and are described by, for example, Eugene You - Xian Chen & Tobin J Marks, Cocatalysts for Metal - Catalyzed Olefin Polymerization: Activators, Activation Processes, and Structure - Activity Relationships 100(4) CHEMICAL REVIEWS 1391-1434 (2000). Examples of neutral ionizing activators include tri-substituted compounds, in particular, tri-substituted boron, tellurium, aluminum, gallium and indium compounds, and mixtures thereof (e.g., tri(n-butyl)ammonium tetrakis(pentafluorophenyl)boron and/or trisperfluorophenyl boron metalloid precursors). The three substituent groups are each independently selected from alkyls, alkenyls, halogen, substituted alkyls, aryls, arylhalides, alkoxy and halides. In one embodiment, the three groups are independently selected from the group of halogen, mono or multicyclic (including halosubstituted) aryls, alkyls, and alkenyl compounds and mixtures thereof. In another embodiment, the three groups are selected from the group alkenyl groups having 1 to 20 carbon atoms, alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms and aryl groups having 3 to 20 carbon atoms (including substituted aryls), and combinations thereof. In yet another embodiment, the three groups are selected from the group alkyls having 1 to 4 carbon groups, phenyl, naphthyl and mixtures thereof. In yet another embodiment, the three groups are selected from the group highly halogenated alkyls having 1 to 4 carbon groups, highly halogenated phenyls, and highly halogenated naphthyls and mixtures thereof. By “highly halogenated”, it is meant that at least 50% of the hydrogens are replaced by a halogen group selected from fluorine, chlorine and bromine. In yet another embodiment, the neutral stoichiometric activator is a tri-substituted Group 13 compound comprising highly fluorinated aryl groups, the groups being highly fluorinated phenyl and highly fluorinated naphthyl groups.
Illustrative, not limiting examples of ionic ionizing activators include trialkyl-substituted ammonium salts such as:
triethylammoniumtetraphenylboron, tripropylammoniumtetraphenylboron, tri(n-butyl)ammoniumtetraphenylboron, trimethylammoniumtetra(p-tolyl)boron, trimethylammoniumtetra(o-tolyl)boron, tributylammoniumtetra(pentafluorophenyl)boron, tripropylammoniumtetra(o,p-dimethylphenyl)boron, tributylammoniumtetra(m,m-dimethylphenyl)boron, tributylammoniumtetra(p-tri-fluoromethylphenyl)boron, tributylammoniumtetra(pentafluorophenyl)boron, tri(n-butyl)ammoniumtetra(o-tolyl)boron, and the like; N,N-dialkylanilinium salts such as: N,N-dimethylaniliniumtetraphenylboron, N,N-diethylaniliniumtetraphenylboron, N,N-2,4,6-pentamethylaniliniumtetraphenylboron and the like; dialkyl ammonium salts such as: diisopropylammoniumtetrapentafluorophenylboron, dicyclohexylammoniumtetraphenylboron and the like; triaryl phosphonium salts such as: triphenylphosphoniumtetraphenylboron, trimethylphenylphosphoniumtetraphenylboron, tridimethylphenylphosphoniumtetraphenylboron, and the like, and their aluminum equivalents.
In yet another embodiment, an alkylaluminum may be used in conjunction with a heterocyclic compound. The ring of the heterocyclic compound may include at least one nitrogen, oxygen, and/or sulfur atom, and includes at least one nitrogen atom in one embodiment. The heterocyclic compound includes 4 or more ring members in one embodiment, and 5 or more ring members in another embodiment.
The heterocyclic compound for use as an activator with an alkylaluminum may be unsubstituted or substituted with one or a combination of substituent groups. Examples of suitable substituents include halogen, alkyl, alkenyl or alkynyl radicals, cycloalkyl radicals, aryl radicals, aryl substituted alkyl radicals, acyl radicals, aroyl radicals, alkoxy radicals, aryloxy radicals, alkylthio radicals, dialkylamino radicals, alkoxycarbonyl radicals, aryloxycarbonyl radicals, carbomoyl radicals, alkyl- or dialkyl-carbamoyl radicals, acyloxy radicals, acylamino radicals, aroylamino radicals, straight, branched or cyclic, alkylene radicals, or any combination thereof. The substituents groups may also be substituted with halogens, particularly fluorine or bromine, or heteroatoms or the like.
Non-limiting examples of hydrocarbon substituents include methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, benzyl or phenyl groups and the like, including all their isomers, for example tertiary butyl, isopropyl, and the like. Other examples of substituents include fluoromethyl, fluoroethyl, difluoroethyl, iodopropyl, bromohexyl or chlorobenzyl.
In one embodiment, the heterocyclic compound is unsubstituted. In another embodiment one or more positions on the heterocyclic compound are substituted with a halogen atom or a halogen atom containing group, for example a halogenated aryl group. In one embodiment the halogen is selected from the group consisting of chlorine, bromine and fluorine, and selected from the group consisting of fluorine and bromine in another embodiment, and the halogen is fluorine in yet another embodiment.
Non-limiting examples of heterocyclic compounds utilized in the activator of the invention include substituted and unsubstituted pyrroles, imidazoles, pyrazoles, pyrrolines, pyrrolidines, purines, carbazoles, and indoles, phenyl indoles, 2,5,-dimethylpyrroles, 3-pentafluorophenylpyrrole, 4,5,6,7-tetrafluoroindole or 3,4-difluoropyrroles.
Other activators include those described in WO 98/07515 such as tris(2,2′,2″-nonafluorobiphenyl) fluoroaluminate, which is incorporated by reference herein. Combinations of activators are also contemplated by the invention, for example, alumoxanes and ionizing activators in combinations. Other activators include aluminum/boron complexes, perchlorates, periodates and iodates including their hydrates; lithium (2,2′-bisphenyl-ditrimethylsilicate)-4T-HF; silylium salts in combination with a non-coordinating compatible anion. Also, methods of activation such as using radiation, electro-chemical oxidation, and the like are also contemplated as activating methods for the purposes of rendering the neutral metallocene-type catalyst compound or precursor to a metallocene-type cation capable of polymerizing olefins. Other activators or methods for activating a metallocene-type catalyst compound are described in for example, U.S. Pat. Nos. 5,849,852 5,859,653 and 5,869,723; and WO 98/32775.
In general, the activator and catalyst component(s) may be combined in mole ratios of activator to catalyst component from 1000:1 to 0.5:1 in one embodiment, and from 300:1 to 1:1 in a more particular embodiment, and from 150:1 to 1:1 in yet a more particular embodiment, and from 50:1 to 1:1 in yet a more particular embodiment, and from 10:1 to 0.5:1 in yet a more particular embodiment, and from 3:1 to 0.3:1 in yet a more particular embodiment, wherein a desirable range may include any combination of any upper mole ratio limit with any lower mole ratio limit described herein. When the activator is a cyclic or oligomeric poly(hydrocarbylaluminum oxide) (e.g., “MAO”), the mole ratio of activator to catalyst component ranges from 2:1 to 100,000:1 in one embodiment, and from 10:1 to 10,000:1 in another embodiment, and from 50:1 to 10,000:1 in a more particular embodiment. When the activator is a neutral or ionic ionizing activator such as a boron alkyl and the ionic salt of a boron alkyl, the mole ratio of activator to catalyst component ranges from 0.5:1 to 10:1 in one embodiment, and from 1:1 to 5:1 in yet a more particular embodiment.
More particularly, the molar ratio of Al/metallocene-metal (e.g., Al from MAO:Zr from metallocene) ranges from 40 to 1000 in one embodiment, ranges from 50 to 750 in another embodiment, ranges from 60 to 500 in yet another embodiment, ranges from 70 to 300 in yet another embodiment, ranges from 80 to 175 in yet another embodiment; and ranges from 90 to 125 in yet another embodiment, wherein a desirable molar ratio of Al(MAO) to metallocene-metal “M” may be any combination of any upper limit with any lower limit described herein.
The activators may or may not be associated with or bound to a support, either in association with the catalyst component (e.g., metallocene) or separate from the catalyst component, such as described by Gregory G. Hlalky, Heterogeneous Single - Site Catalysts for Olefin Polymerization 100(4) CHEMICAL REVIEWS 1347-1374 (2000).
Metallocene catalysts may be supported or unsupported. Typical support materials may include talc, inorganic oxides, clays and clay minerals, ion-exchanged layered compounds, diatomaceous earth compounds, zeolites or a resinous support material, such as a polyolefin.
Specific inorganic oxides include silica, alumina, magnesia, titania and zirconia, for example. The inorganic oxides used as support materials may have an average particle size of from 5 microns to 600 microns, or from 10 microns to 100 microns, a surface area of from 50 m 2 /g to 1,000 m 2 /g, or from 100 m 2 /g to 500 m 2 /g, a pore volume of from 0.5 cc/g to 3.5 cc/g, or from 0.5 cc/g to 2 cc/g.
Desirable methods for supporting metallocene ionic catalysts are known in the art and described in, for example, U.S. Pat. No. 5,643,847, which is incorporated by reference herein. The methods generally include reacting neutral anion precursors that are sufficiently strong Lewis acids with the hydroxyl reactive functionalities present on the silica surface such that the Lewis acid becomes covalently bound.
When the activator for the metallocene supported catalyst composition is a NCA, desirably the NCA is first added to the support composition followed by the addition of the metallocene catalyst. In some processes, when the activator is MAO, the MAO and metallocene catalyst may be dissolved together in solution. The support is then contacted with the MAO/metallocene catalyst solution. In another embodiment of the process, MAO is first reacted with silica and then a metallocene is added to prepare a catalyst. Other methods and order of addition will be apparent to those skilled in the art. Such processes are known in the art and disclosed in, for example, U.S. Pat. Nos. 6,777,366 and 6,777,367, both to Gauthier, et al., and incorporated herein by reference.
In one embodiment, the heterocyclic compound described above is combined with an alkyl aluminum scavenger. The alkyl aluminum compounds can remove or mitigate materials such as water and oxygen that could otherwise interfere with the metallocene catalysts. Non-limiting examples of alkylaluminums include trimethylaluminum, triethylaluminum (TEAL), triisobutylaluminum (TIBAL), tri-n-hexylaluminum, tri-n-octylaluminum, tri-iso-octylaluminum, triphenylaluminum, and combinations thereof. While most often used as scavengers, the compounds can also, in some applications, function as cocatalysts or activators also. One of ordinary skill in the art of performing metallocene catalyzed polyolefin polymerizations will be versed in selecting and employing such scavengers.
Metallocene catalysts may be supported or unsupported. Typical support materials may include talc, inorganic oxides, clays and clay minerals, ion-exchanged layered compounds, diatomaceous earth compounds, zeolites or a resinous support material, such as a polyolefin. Specific inorganic oxides include silica, alumina, magnesia, titania and zirconia, for example. The inorganic oxides used as support materials may have an average particle size of from 5 microns to 600 microns, or from 10 microns to 100 microns, a surface area of from 50 m 2 /g to 1,000 m 2 /g, or from 100 m 2 /g to 400 m 2 /g, a pore volume of from 0.5 cc/g to 3.5 cc/g, or from 0.5 cc/g to 2 cc/g.
Desirable methods for supporting metallocene ionic catalysts are known in the art and described in, for example, U.S. Pat. No. 5,643,847, which is fully incorporated by reference herein. The methods generally include reacting neutral anion precursors that are sufficiently strong Lewis acids with the hydroxyl reactive functionalities present on the silica surface such that the Lewis acid becomes covalently bound. Activators may also be incorporated onto the support, using processes such as those disclosed in, for example, U.S. Pat. Nos. 6,777,366 and 6,777,367, both to Gauthier, et al., both of which are fully incorporated herein by reference.
To prepare a polymer it is necessary, in general, to contact the monomer or mixture of monomers and the given metallocene catalyst and the described cocatalyst(s). In certain cases it is desirable that the catalyst has been preactivated. Those skilled in the art will understand that this refers to subjecting the metallocene catalyst to conditions that promote the desired interaction between the activator or cocatalyst and the metallocene. The most commonly employed method of activating a catalyst is simply heating it to a sufficient temperature and for a sufficient time, determined as a matter of routine experimentation. This is discussed further in, for example, U.S. Pat. No. 6,180,732, the disclosure of which is fully incorporated herein by reference. Other methods can be used. Those skilled in the art will appreciate that modifications in the above generalized preparation method may be made without altering the outcome. Therefore, it will be understood that additional description of methods and means of preparing the catalyst are outside of the scope of the invention, and that it is only the identification of the prepared catalysts, as defined herein, that is necessarily described herein.
The metallocene catalysts described herein may be used to make copolymers using monomers including ethylene and propylene. A variety of processes may be employed to prepare the copolymers. Among the varying approaches that may be used include procedures set forth in, for example, U.S. Pat. No. 5,525,678, which is fully incorporated herein by reference. The equipment, process conditions, reactants, additives and other materials will, of course, vary in a given process, depending on the desired composition and properties of the polymer being formed. For example, the processes discussed in any of the following patents may be useful, each of which is fully incorporated herein by reference: U.S. Pat. Nos. 6,420,580; 6,380,328; 6,359,072; 6,346,586; 6,340,730; 6,339,134; 6,300,436; 6,274,684; 6,271,323; 6,248,845; 6,245,868; 6,245,705; 6,242,545; 6,211,105; 6,207,606; 6,180,735; and 6,147,173.
The catalyst systems described herein, including the identified family of cocatalysts, may be used over a wide range of temperatures and pressures. The temperatures may be in the range of from about 20° C. to about 280° C., or from about 50° C. to about 200° C. and the pressures employed may be in the range of from 1 atmosphere to about 500 atmospheres (0.10 mPa to 50.66 mPa) or higher. Such polymerization processes include solution, bulk, gas phase, slurry phase, high pressure processes, and combinations thereof.
Examples of solution processes are described in U.S. Pat. Nos. 4,271,060; 5,001,205; 5,236,998; and 5,589,555; and are fully incorporated herein by reference.
One example of a gas phase polymerization process generally employs a continuous cycle, wherein a cycling gas stream (otherwise known as a recycle stream or fluidizing medium) is heated in a reactor by heat of polymerization. The heat is removed from the recycle stream in another part of the cycle by a cooling system external to the reactor. The gaseous stream containing one or more monomers may be continuously cycled through a fluidized bed in the presence of a catalyst under reactive conditions. The gaseous stream is withdrawn from the fluidized bed and recycled back into the reactor. Simultaneously, polymer product is withdrawn from the reactor and fresh monomer is added to replace the polymerized monomer. See, for example, U.S. Pat. Nos. 4,543,399; 4,588,790; 5,028,670; 5,317,036; 5,352,749; 5,405,922; 5,436,304; 5,456,471; 5,462,999; 5,616,661; and 5,668,228 are fully incorporated herein by reference.
The reactor pressure in a gas phase process may vary from about 100 psig to about 500 psig (about 689.47 kPa to about 3,447.38 kPa), or from about 200 to about 400 psig (1378.95 kPa to 2757.90 kPa), or from about 250 to about 350 psig (1723.69 kPa to 2413.16 kPa). The reactor temperature in a gas phase process may vary from 30° C. to 120° C. in one embodiment, or 60° C. to 115° C. in an additional embodiment, or 70° C. to 110° C. or 70° C. to 95° C. in further embodiments.
Other gas phase processes contemplated by the process includes those described in U.S. Pat. Nos. 5,627,242; 5,665,818; and 5,677,375; and European publications EP-A-0 794 200; EP-A-0 802 202; and EP-B-634 421; all of which are fully incorporated herein by reference.
Slurry processes generally include forming a suspension of solid, particulate polymer in a liquid polymerization medium, to which monomers and optionally hydrogen, along with catalyst, are added. The suspension, including the polymerization diluent, may be intermittently or continuously removed from the reactor where the volatile components may be separated from the polymer and recycled, optionally after a distillation, to the reactor. The liquefied diluent employed in the polymerization medium is typically an alkane having from 3 to 7 carbon atoms, preferably a branched alkane. The medium employed should be liquid under the conditions of polymerization and relatively inert, such as hexane or, in one particularly desirable embodiment, isobutane.
The catalyst as a slurry or as a dry free flowing powder may be injected regularly to the reactor loop, which can itself be filled with circulating slurry of growing polymer particles in a monomer. Hydrogen, optionally, may be added as a molecular weight control. The reactor may be maintained at a pressure of from about 27 bar (2.7 mPa) to about 45 bar (4.5 mPa) (and a temperature of from about 38° C. to about 121° C. Reaction heat can be removed through the loop wall since much of the reactor is in the form of a double-jacketed pipe. The slurry may exit the reactor at regular intervals or continuously to a heated low pressure flash vessel, rotary dryer and a nitrogen purge column in sequence for removal of unreacted monomer and comonomers. The resulted hydrocarbon free powder can then be compounded for use in various applications. Alternatively, other types of slurry polymerization processes can be used, such stirred reactors is series, parallel or combinations thereof.
A slurry and/or polymerization process generally includes pressures in the range of 1 to 50 atmospheres (0.10 to 5.06 mPa) and even greater and temperatures of from about 0° C. to about 120° C.
A solution process can also be used. Examples of solution processes are described in U.S. Pat. Nos. 4,271,060; 5,001,205; 5,236,998; and 5,589,555, all of which are fully incorporated herein by reference.
In one embodiment the invention may be a copolymer prepared using a metallocene catalyst wherein the metallocene catalyst includes a bis-indenyl metallocene. The copolymer may be a random copolymer of propylene and ethylene. Ethylene may be present at weight percentage of from about 3 to about 5 percent. The copolymer may have a ductile/brittle transition of from about −7° C. to about 0° C. The copolymer may have a melting point of from about 108 to about 120 and, in one embodiment, has a melting point of about 114° C.
In another embodiment, the invention may be a copolymer prepared using a metallocene catalyst wherein the metallocene catalyst includes a CpFlu metallocene. The copolymer may be a random copolymer of propylene and ethylene. Ethylene may be present at weight percentage of from about 1.8 to about 3 percent. The copolymer may have a ductile/brittle transition of from about −7° C. to about 0° C. The copolymer may have a melting point of from about 108 to about 120 and, in one embodiment, may have a melting point of about 113° C.
The metallocene random copolymer may have an ethylene content, typically greater than about 2.0 weight %, alternatively greater than about 5 wt %, alternatively greater than about 6 wt %, and even about 6.5 wt %, as measured by carbon-13 nuclear magnetic resonance spectroscopy ( 13 C-NMR). All weight percentages (wt %) are per total weight of the copolymer. Metallocene random copolymers of the invention may be produced and marketed under the same name but different lots might have differences in the levels of ethylene and in other characteristics. As with other random copolymers, the ethylene may be in the backbone of the polymer chain, randomly inserted in the repeating propylene units.
The processes useful in preparing metallocene random copolymers having good impact resistance and high clarity are well known in the art of preparing such copolymers and may be made by using processes such as those disclosed in U.S. Pat. Nos. 5,158,920; 5,416,228; 5,789,502; 5,807,800; 5,968,864; 6,225,251; and 6,432,860; all of which are fully incorporated herein by reference. Standard equipment and procedures as are well known in the art may be used to polymerize the propylene and ethylene into the metallocene random copolymer.
A clarifier may optionally be added to the metallocene random copolymer for clarity enhancement. Since the clarifier is not necessarily included in the metallocene random copolymer, the lower limit on the amount of clarifier is 0 parts per million (ppm) by weight. The upper limit may be typically the U.S. Food and Drug Administration limit on such materials, which in this case is 4000 ppm. A desirable range for the clarifier may be 1000 ppm to 3000 ppm. A more desirable clarifier level may be about 2000 ppm. Suitable clarifiers include dibenzylidene sorbitols (CDBS), organophosphate salts, and phosphate esters. Examples of a commercially available clarifiers are Millad 3988, 3905, and 3940, powdered sorbitols available from Milliken Chemical of Spartanburg, S.C.; NA-11 and NA-21 phosphate esters available from Asahi Denka Kogyo; NC-4 from Mitsui Chemicals; HPN-68, a norbornane carboxylic-acid salt available from Milliken Chemical; and Irgaclear D or DM sorbitol based clarifiers available from Ciba Specialty Chemicals. Of course other clarifiers known to one skilled in the art for such purposes can also be used.
If the clarifier is to be included in the metallocene random copolymer, the clarifier, typically in the form of a powder or pellet, may be added to the copolymer after the polymerization process described above but before the copolymer is melted and formed into pellets. The copolymer and the clarifier are typically dry blended into a polymer blend for subsequent forming into end-use articles. Examples of apparatus suitable for blending the materials include a Henschel blender or a Banbury mixer, or alternatively low shear blending equipment of the type that typically accompanies a commercial blow molding or sheet extrusion line. The clarifier increases clarity by greatly increasing the rate of crystal formation in the copolymer. During the normal, slower crystallization process, relatively large crystals tend to form. These large crystals refract light and thus reduce the clarity of a copolymer. When the clarifier is added, the higher rate of crystal formation results in a greater number of smaller-sized crystals. The smaller crystals allow light to pass without refraction, thus increasing the clarity of the copolymer.
In addition to the clarifier, other additives may optionally be added to the metallocene random copolymer. The additives may include stabilizers, ultraviolet screening agents, oxidants, antioxidants, anti-static agents, ultraviolet light absorbents, lubricants, fire retardants, processing oils, mold release agents, coloring agents, pigments, nucleating agents, fillers, and the like. Additives may be suited for the particular needs or desires of a user or maker and various combinations of the additives may be used.
In some embodiments of the invention, the additives used may include a neutralizer such as Irganox 1076 and/or Irgafos 168, which are commercially available from the Ciba-Geigy Corporation. In other embodiments, the additive used may include Ethanox 330, an antioxidant available from Ethyl. In another embodiment, the additives used may include a hydrotalcite such as those with the trade name DHT4A, available from Kyowa Chemical Industries Co., LTD, for example. Another neutralizer that may be used with the invention is calcium stearate.
The radiation exposure may be from, for example, Co 60 gamma radiation or lower level radiation, such as that from E-beam radiation. The radiation exposure may be that used in sterilization techniques for medical or food handling applications. The materials of the invention may have application where radiation exposure is usually in the range of 1-6 mega rads (Mrads).
Ziegler-Natta catalysts also useful in the preparation of isotactic polypropylene are typically derived from a halide of a transition metal, such as titanium, chromium or vanadium with a metal hydride and/or metal alkyl, typically an organoaluminum compound as a co-catalyst. The catalyst is usually comprised of a titanium halide supported on a magnesium compound. Ziegler-Natta catalysts, such as titanium tetrachloride (TiCl 4 ) supported on an active magnesium dihalide, such as magnesium dichloride or magnesium dibromide, as disclosed, for example, in U.S. Pat. Nos. 4,298,718 and 4,544,717, both to Mayr et al., and which are fully incorporated herein by reference, are supported catalysts. Silica may also be used as a support. The supported catalyst may be employed in conjunction with a co-catalyst or electron donor such as an alkylaluminum compound, for example, triethylaluminum (TEAI), trimethyl aluminum (TMA) and triisobutyl aluminum (TiBAI). Ziegler-Natta catalyst systems incorporating diethers and succinates may also be used with the invention.
The isotactic polypropylene used in the present invention may be a propylene homopolymer, which may be prepared from either Ziegler-Natta or metallocene catalyst useful in preparing istotactic polymers. As used herein, “homopolymer” shall mean those polymers having less than about 0.1% by weight of polymer of other comonomers. The isotactic polypropylene component employed will typically have a meso dyad content, as determined by 13 C-NMR spectra, of at least 75%, and may be at least 95% or more. For metallocene-catalyzed isotactic polypropylene the polymer will typically have a molecular weight distribution or polydispersity index (Mw/Mn) of less than about 4.0, with from about 2.5 to about 3.5 being typical. Reactor grade metallocene-catalyzed polypropylenes typical have a melt flow rate of from about 0.5 g/10 minutes to about 48 g/10 min, but is often further treated to produce melt flow rates targeted for specific applications. For example, polymers to be employed in spunbond applications may typically have a melt flow rate of from about 14 to about 37 g/10 minutes. In another embodiment, the polymer to be used in a melt blown application may have a melt flow rate of from about 50 to about 1700 g/10 minutes, as measured by ASTM-D1238, Condition L at 230° C. The metallocene-catalyzed isotactic polypropylene may have a xylene solubles of less than about 1 weight percent, with from about 0.2 to about 0.5 being typical, as measured by ASTM-D5492.
For Ziegler-Natta isotactic polypropylene, the polymer may typically have a molecular weight distribution of from about 4 to about 15. Controlled rheology Ziegler-Natta polypropylene polymers typically have a higher xylene solubles compared to miPP. The ZNiPP will typically have xylene solubles of greater than 1, more typically from about 1.5 to about 5.0, with 2% being common. Because reactor-grade ZN-iPP typically has a fairly broad molecular weight distribution, it is often necessary for the polymer to undergo further processing to narrow its molecular weight distribution, such as for use in high speed melt spinning.
The isotactic polypropylene used in the present invention may also include isotactic propylene random copolymers, which may be prepared from either Ziegler-Natta or metallocene catalysts useful in the preparation of isotactic polymers. As used herein, “copolymers” shall mean those propylene polymers having 0.1% or more by weight of polymer of other comonomers. The isotactic propylene component of the random copolymers employed will typically have a meso dyad content, as determined by 13 C-NMR spectra, of at least 75%, and may be at least 95%. Those isotactic copolymers typically used in the present invention are those propylene copolymers of the olefin monomers having from 2 to 10 carbon atoms, with ethylene being the most typical comonomer employed. Typically, the comonomer will make up from about 0.1% to about 10% by weight of polymer, with from about 0.5% to about 6% being typical, and from 1% to about 3% being more typical. Copolymers will often have higher xylene solubles content.
The syndiotactic polypropylene used in the present invention may be a polypropylene homopolymer or polypropylene random copolymer. The syndiotactic polypropylene component typically has a racemic dyad content, as measured by 13 C-NMR spectra, of at least 75%, and may be at least 90% or more. The syndiotactic polypropylene will typically have a molecular weight distribution (MWD) or polydispersity index (Mw/Mn) of less than about 5, and may typically range from 2 to about 4.5. The melt flow rate of the syndiotactic polypropylene will usually be from about 5 g/10 minutes to about 30 g/10 minutes, with from about 10 g/10 minutes to about 20 g/10 minutes being more typical. The melt flow rate of the syndiotactic polypropylene may vary, however, depending upon the particular application. The metallocene-catalyzed syndiotactic polypropylene may have a xylene solubles of less than about 9, with from about 4 to about 9 being typical.
The syndiotactic polypropylene may also include copolymers of olefin monomers having from 2 to 10 carbon atoms, with ethylene being the most common comonomer employed. Typically, the comonomer will make up from about 0.1% to about 10% by weight of polymer, with from about 0.5% to about 6% being typical, and from 1% to about 3% being more typical.
The addition of syndiotactic polypropylene as a blend with isotactic polypropylene, either Ziegler-Natta or metallocene-catalyzed isotactic polypropylene has been found to increase the polymer's radiation resistance or reduce degradation of the polymer from radiation when compared to the same polymer without the syndiotactic polypropylene. Where such blends are employed, the amount of syndiotactic polypropylene may be less than 20% by total weight of polymer, with from about 0.5% to about 10% being more typical. The polymer blends may be melt blended within an extruder, such as during extrusion of the polymer sheet. Alternatively, the polymer blends may be reactor blended, such as described in U.S. Pat. No. 6,362,125, which is fully incorporated herein by reference.
The final melt flow rate of the polypropylene materials may vary, depending upon the particular application. In certain cases the propylene polymers may be modified or degraded to further change the characteristics of the polymer through controlled rheology techniques, which are known to those skilled in the art. This is typically done to adjust the polymer's final melt flow characteristics so that it has a higher melt flow rate. This may be particularly true with respect to ZN-iPP, which typically has a low MFI without CR'ing. Modification of the polymer may be accomplished through the addition of peroxides or other free-radical initiators, which degrade the polymer to thereby increase its melt flow rate.
The isotactic and syndiotactic propylene polymers may contain radiation stabilization additives or combinations of such stabilizers. These additives or stabilizers react with the alkyl radicals formed during irradiation and thereby terminate the chain reaction early on and thus reduce loss of polymer properties.
Such radiation stabilizers include the non-phenolic compounds of benzhydrols or derivatives of benzhydrol. Such compounds are aromatic compounds and are described in U.S. Pat. No. 4,431,497, which is herein incorporated by reference. Such stabilizers typically used in amounts of from about 500 to about 5000 ppm although these amounts may vary.
The stabilizers may also include the hindered amine light stabilizer (HALS) compounds, such the tetraalkyl-piperidene-containing polytriazine compounds, including the derivatives of 2,2,6,6-tetramethylpiperidine. Such compounds are described in U.S. Pat. Nos. 4,086,204, 4,234,707, 4,331,586, 4,335,242, 4,459,395, 4,492,791, 5,204,473 and 6,409,941, as well as EP0053775, EP0357223, EP0377324, EP0462069, EP0782994, and GB 2,301,106, all of which are herein incorporated by reference. An example of a suitable stabilizer is:
poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethl-4-piperidinyl)imino-1,6-hexanediyl[2,2,6,6-tetramethyl-4-piperidinyl)imino]]),
which is commercially available as CHIMASSORB 944, from Ciba Specialty Chemicals, Inc. Such compounds are typically used in amounts of from about 0.05 to about 1.0% by weight of polymer, although these amounts may vary.
Another useful stabilizer is the benzofuran-2-one type compounds. Such compounds are described in U.S. Pat. Nos. 4,325,863; 4,388,244; 5,175,312; 5,252,643; 5,216,052; 5,369,159; 5,488,117; 5,356,966; 5,367,008; 5,428,162; 5,428,177; 5,516,920 and 6,140,397, all of which are herein incorporated by reference. Such stabilizers are carbon-centered free radical scavengers may be used alone, or in combination with other stabilizers. The benzofuran-2-one type compounds may be used to regenerate such compounds in a regeneration cycle, where such compounds would be otherwise depleted during use. An example of a useful benzofuran-2-type compound is 5,7-di-t-butyl-3-(3,4 di-methylphenyl)-3H-benzofuran-2-one, which is commercially available as HP-136, from Ciba Specialty Chemicals, Inc. Such compounds are typically used in amounts of from 0.005 to about 0.05% by weight of polymer, although these amounts may vary.
Other additives may include such things as acid neutralizers, anti-static agents, lubricants, filler materials, mobilizing agents such as hydrocarbons, halogenated hydrocarbons, phthalates, polymeric fats, vegetable oils, silicone oils, and the like, which are well known to those skilled in the art.
The choice of radiation stabilizers or other additives may depend upon the type of polypropylene employed. Certain stabilizers or additives may react with peroxide used during controlled rheology so that they are consumed or are less effective. With respect to the radiation stabilizers or antioxidants, these may be consumed by the reaction with peroxide so that their effectiveness in preventing degradation from radiation exposure is reduced or eliminated.
Because reactor-grade metallocene-catalyzed polypropylene materials may have a higher melt flow rate than reactor-grade Ziegler-Natta-catalyzed polypropylenes, it may not be necessary for the miPP or msPP materials to be processed further through controlled rheology techniques. The addition of peroxide to the polymer during controlled rheology to increase the polymer's melt flow rate may thus be eliminated in these materials. Thus, the metallocene-catalyzed polymers may contain little or no peroxide or peroxide residues to react with the radiation stabilizers or other antioxidants.
Polypropylene fibers prepared from the radiation resistant polypropylene material may be used in fabrics and textiles and can be prepared using a variety of different methods. Such methods include spinning, melt blowing and the fibrillation of films into fibers. The polypropylene fibers may have different deniers, lengths and cross-sectional configurations and can be consolidated or networked in many different ways to provide fabrics and textiles having different characteristics and properties. The fibers may be formed into both woven and non-woven fabrics. Woven fabrics are formed through the conventional weaving or knitting techniques.
Non-woven materials may be produced using spunbonding or melt blowing techniques, in which the fabric is formed from generally continuous polymer fibers that are joined together at random cross-over points. Melt blown fibers typically have a denier of from about 50 to about 2000. They may be formed using polypropylene polymers having a final melt flow of about 700 to about 2000 g/10 min, more typically from about 800 to about 1500 g/10 minutes and with a molecular weight distribution of from about 2.5-4.5. Spunbond fibers typically have a denier of from about 20 to about 40. They may be formed from polypropylene having a final melt flow of about 15 to about 45 g/10 minutes, more typically from about 20 to about 35 g/10 minutes and having a molecular weight distribution of from about 2 to 4.5.
Additionally, staple fibers, which are filaments or fibers that are cut into smaller lengths or “staples,” can be formed into non-woven fabric material. Staple fibers typically have a denier of from about 1.5 to about 5.0. They may be formed from polypropylene having a final melt flow of about 4 to about 20 g/10 min, more typically from about 5 to about 15 g/10 minutes and having a molecular weight distribution of from about 2 to about 10, more typically from about 2 to about 8. Such staple fibers may be carded and joined together, such as through thermal bonding or by needle punch. The fibers may also be entangled or otherwise networked into a fabric material, such as through hydroentaglement or otherwise.
Different materials may be laminated or formed into composite materials. Two or more fabric materials may be joined together. Further, one or more fabrics may be joined to a layer or layers of film or to other non-fabric materials, such as superabsorbents or activated charcoal. The polypropylene or polymer materials are typically joined together through thermal bonding, however, resin bonding or other bonding methods may be employed as well.
One particular laminated or composite fabric that is commonly manufactured is spunbonded-meltblown-spunbonded (SMS) composite fabric material. This material utilizes outer layers of spunbonded nonwoven fabric, which provide strength to the fabric. The outer layers of spunbonded fabric are laminated to an inner layer of meltblown nonwoven fabric material, which serves as a barrier layer. The resulting composite fabric has good strength and barrier properties. SMS fabrics are often employed in medical and surgical environments in which the material must be sterilized. As a result, it is important for such materials to have good resistance to radiation.
The polypropylene materials may be used for or in a variety of different products or articles. Non-limiting examples include materials for diapers or incontinence products, sanitary towels, tampons and pads, protective and work clothing, disposable clothing, gowns, masks, insulating material, headwear, overshoes, flannels, bandages, bedcloths, wipes, syringes, tongue depressors, vacuum cleaner bags, tea bags and coffee filters, book covers, carpet underlay, wall coverings, bedclothes, table cloths, covers, mattress filing and covering material, furniture fabrics, cushion covers, upholstery and wadding, filters, air filters, gas filters, water filters, oil adsorbent materials, sanding material, cable sheaths, insulation tape, reinforcements, insulation, roof sealing. They may be used in geotextiles, such as in road and railway construction, dyke and canal construction, soil stabilization, drainage systems, golf, park and sporting ground surfacings, capillary mats in farming and agriculture, covering material for crop forcing and seedling protection. The materials may be used for greenhouse shielding and as packaging materials for fruits, vegetables or produce. The materials may be used in the automobile industry as insulation material, roof linings, battery separators and coating carriers. They may be used for luggage and handbags, sacks, carrier bags, bags, packaging. They may be used in self-adhesive materials, tents, cheese wrappers, artist's canvas and in advertising articles.
Metallocene catalyzed isotactic and syndiotactic polypropylene homopolymers, ethylene propylene random copolymers, and heterophasic copolymers offer superior properties after irradiation in other applications. Ziggler-Natta catalyzed polypropylene polymers and copolymers are often used in gamma resistant applications requiring moderate impact resistance after irradiation such as but not limited to: sterilization of food packaging, laboratory equipment, and medical applications. Metallocene catalyzed polymers and copolymers are more resistant to the degradation caused by irradiation. Many medical or food applications such as these require low odor and low aqueous or chemical extractables, thus metallocenes that do not use peroxides or use less peroxide may be particularly useful.
Other reasons why metallocenes catalyzed polymers and copolymers are well suited for these applications include 1) they have less extractables relative to Ziegler-Natta catalyzed resins with similar copolymer content, 2) they retain their clarity at ethylene levels above 3 wt % by NMR, and 3) improved mixing with other polymers and copolymers and color concentrates because of narrow molecular weight distribution. In these applications, the metallocene catalyzed polymers and copolymers may be either neat or blended with other non-metallocene polymers and copolymers.
The following examples are provided to more fully illustrate the invention. As such, they are intended to be merely illustrative and should not be construed as being limitative of the scope of the invention in any way. Those skilled in the art will appreciate that modifications may be made to the invention as described without altering its scope. For example, selection of particular monomers or combinations of monomers; and modifications such as of catalyst concentration, feed rate, processing temperatures, pressures and other conditions, and the like, not explicitly mentioned herein but falling within the general description hereof, will still fall within the intended scope of both the specification and claims appended hereto.
EXAMPLES
Various polypropylene materials were prepared for use in fabric materials. The characteristics and properties of the polypropylene materials used are presented in Table 1, below. Unless otherwise specified, all percentages are by total weight of polymer.
TABLE 1
Resin Sample
1
3
ZN-iPP
2
ZN-iPP
4
(Spunbond)
m-sPP
(Melt Blown)
m-iPP
Initial MFR (g/10 min)
1.5
4
350
30
Final MFR (g/10 min)
22
4.5
918
32
Additives
DHT-4A, (%) A
0.02
0.02
0.02
0.02
Milliken RS200 (%)
0.2
0.2
0.2
0.2
Chimasorb 944 (%)
0.2
0.2
0.2
0.2
Lupersol 101 (%)
0.05
0
n.a. B
0
GMS (%) C
0.04
0.04
0.04
0.04
EBS (%) D
0
0.1
0
0
A Stabilizer from Kyowa Chemical Industry Co
B Amount not precisely known but estimated to be about 600-800 ppm
C Glycerol monostearate
D Ethylene bisstearamide
The above materials are used in forming either spunbonded or melt blown fiber materials. The syndiotactic polypropylene of Sample 2 was combined with isotactic polypropylene of both Samples 1 and 4 in amounts of approximately 5% by total weight of polymer by pellet/pellet tumble blending. Table 2 sets forth the make up of the different fabric samples. These materials are then used to prepare a spunbonded/meltblown/spunbonded (SMS) laminated fabric. The SMS fabric is produced on a 1.5 meter STP Impianti SMS fabric line, which utilizes two spunbonded beams and a single melt blown die. The spunbond unit had a slot-design aspirator unit to draw down the fibers at approximately 2000 m/min. The melt spinning temperatures at the spunbond beam were held constant at approximately 235° C.
TABLE 2 SMS Fabric 1 st Spunbond Melt Blown 2 nd Spunbond Sample Layer Layer Layer 1* ZN-iPP ZN-iPP ZN-iPP (Sample 1) (Sample 3) (Sample 1) 2 ZN-iPP (Sample 1) + ZN-iPP (Sample ZN-iPP (Sample 5 wt % m-sPP 3) 1) + 5 wt % m- (Sample 2) sPP (Sample 2) 3* m-iPP (Sample 4) ZN-iPP m-iPP (Sample 3) (Sample 4) 4 m-iPP (Sample 4) + ZN-iPP (Sample m-iPP (Sample 5 wt % m-sPP 3) 4) + 5 wt % m- (Sample 2) sPP (Sample 2) *Comparative example, not an example of the invention.
The SMS fabric samples are then subjected to gamma radiation using a Cobalt 60 radiation source at the dosage levels set forth in Table 3. In certain cases, the fabric was oven aged in a convection oven at a temperature of approximately 60° C. for six weeks. Various properties of the SMS fabric material were then measured and are set forth in Tables 3 A&B below. These included machine-direction (MD) and cross-direction (CD) grab strength, tear strength, and elongation. The term “trap” refers to the test specimen shape. In Table 3C, the percent elongation retained in both the machine direction and the cross machine direction are calculated and displayed. Sample 2 is then compared to Sample 1 and Sample 4 is compared to Sample 3 and the comparative retained elongation is calculated and displayed in Table 3C. Overall average percent elongation retention is also calculated and displayed in Table 3C.
TABLE 3A
CD-
SMS
Basis
CD
MD-Trap
Trap
Fabric
Radiation
Weight
MD Grab
Grab
Tear
Tear
Sample
and Aging Conditions
(oz./yd)
(lb/in)
(lb/in)
(g)
(g)
1
Non-Irradiated
1.46
28
20
14
11
3 Mrads
1.46
21
14
10
6
3 Mrads + 6 wks. Oven Aging
1.46
19
13.5
6.2
4
6 Mrads
1.46
17
12
8
4
6 Mrads + 6 wks. Oven Aging
1.42
13.1
8.8
3.2
2.2
10 Mrads
1.42
11
6
2.3
1.5
2
Non-Irradiated
1.52
28
20
14
9
3 Mrads
1.52
18
14
13
7
3 Mrads + 6 wks. Oven Aging
1.48
18.1
14.6
7.4
4.5
6 Mrads
1.48
18
17
8
5
6 Mrads + 6 wks. Oven Aging
1.59
13.7
7.7
3.3
2.3
10 Mrads
1.59
15
10
7
3.4
3
Non-Irradiated
1.39
25
18
12
8
3 Mrads
1.39
22
17
11
7
3 Mrads + 6 wks. Oven Aging
1.37
16.7
13.5
6.7
4.5
6 Mrads
1.37
19
13
7
5
6 Mrads + 6 wks. Oven Aging
1.33
14.2
9.6
4.3
2.6
10 Mrads
1.33
15
11
6
3
4
Non-Irradiated
1.48
25
18
15
9
3 Mrads
1.48
18
16
10
6
3 Mrads + 6 wks. Oven Aging
1.50
21
14.7
7.1
5.1
6 Mrads
1.50
19
13
8
6
6 Mrads + 6 wks. Oven Aging
1.53
15.1
11.1
4.5
3.1
10 Mrads
1.53
13
8.6
6
3
TABLE 3B
SMS
MD-
CD-
Fabric
Radiation
Elong.
Elong.
Air Perm.
Sample
and Aging Conditions
(%)
(%)
(cfm/ft 2 )
1
Non-Irradiated
80
93
154
3 Mrads
45
54
143
3 Mrads + 6 wks. Oven Aging
36.4
43
145
6 Mrads
39
41
138
6 Mrads + 6 wks. Oven Aging
22.9
23.5
143
10 Mrads
17
19
143
2
Non-Irradiated
79
93
138
3 Mrads
68
64
168
3 Mrads + 6 wks. Oven Aging
38.8
43.4
165
6 Mrads
49
43
150
6 Mrads + 6 wks. Oven Aging
22.7
31.4
178
10 Mrads
35
49
148
3
Non-Irradiated
101
103
136
3 Mrads
57
62
138
3 Mrads + 6 wks. Oven Aging
40.8
42.6
169
6 Mrads
40
42
142
6 Mrads + 6 wks. Oven Aging
30.5
36.8
174
10 Mrads
28
29
139
4
Non-Irradiated
93
94
136
3 Mrads
61
70
144
3 Mrads + 6 wks. Oven Aging
38.7
41
153
6 Mrads
48
53
143
6 Mrads + 6 wks. Oven Aging
28.5
32.8
124
10 Mrads
30
40
130
TABLE 3C SMS MD- MD CD- CD Overall Fabric Radiation % Elong. Comp % % Elong Comp % Avg Sample and Aging Conditions Retained Retained Retained Retained MD/CD 1 Non-Irradiated — — 3 Mrads 56 58 3 Mrads + 6 wks. Oven Aging 45 46 6 Mrads 48 44 6 Mrads + 6 wks. Oven Aging 28 25 10 Mrads 21 20 2 Non-Irradiated — — — — 15.6/11.0 3 Mrads 86 36 69 11 3 Mrads + 6 wks. Oven Aging 49 5 47 1 6 Mrads 62 14 46 2 6 Mrads + 6 wks. Oven Aging 28 0 34 9 10 Mrads 44 23 52 32 3 Non-Irradiated — — 3 Mrads 56 60 3 Mrads + 6 wks. Oven Aging 41 41 6 Mrads 40 41 6 Mrads + 6 wks. Oven Aging 30 36 10 Mrads 28 28 4 Non-Irradiated — — — — 5.4/8.2 3 Mrads 66 10 74 14 3 Mrads + 6 wks. Oven Aging 41 0 44 3 6 Mrads 52 12 56 15 6 Mrads + 6 wks. Oven Aging 31 1 33 −3 10 Mrads 32 4 34 6
The SMS fabric samples incorporating 5 percent metallocene polypropylene components in the spunbond layers out performed those fabric samples that did not incorporate 5 percent metallocene polypropylene components at retaining toughness after exposure to radiation and after exposure to both radiation and oven heat aging. For example, the SMS fabrics of the invention have a 50% or greater retention of machine direction elongation strength at a radiation dose of 3-6 Mrads
While the invention has been shown in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes and modifications without departing from the scope of the invention. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.
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A polypropylene material is provided having increased radiation resistance compared to solely isotactic polypropylene. The material is formed by utilizing a syndiotactic polypropylene. The isotactic polypropylene may be an isotactic metallocene or Ziegler-Natta catalyzed polypropylene and may include an amount of syndiotactic polypropylene. The material may be used in forming a variety of materials that may undergo exposure to radiation, such as sterilization procedures using radiation. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.
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FIELD OF THE INVENTION
This invention is related to the field of configuring cylindrical objects, and more specifically to forming an outwardly projecting bead on a spinning cylindrical object.
BACKGROUND OF THE INVENTION
Cylindrical objects, such as containers and cans, are available in a variety of types and configurations. Two of the more common types are two-piece containers and three-piece containers. Two-piece containers are typically manufactured by a drawing and ironing process. In such processes a cup-shaped metal blank is drawn, optionally redrawn, then passed through successive ironing rings in order to lengthen and thin the sidewalls of the container. The open end of the two-piece container is then closed with a separate end piece. Three-piece containers are typically manufactured from metal roll stock that is cut into strips having a width that will substantially define the height of the resultant containers. Each strip is formed into a cylindrical shape and a longitudinal seam is established, e.g. by welding. The two open ends are then closed by attaching end pieces.
It is often desirable to alter the configuration of the sidewalls of cylindrical containers, including two-piece and three-piece containers, during the manufacturing process. For instance, the open end or ends of a container may be flanged in order to facilitate the attachment of end pieces. Additionally, the "necking-in" (i.e. reduction of diameter) of at least one end of the sidewalls of containers in order to reduce the material required for closing and sealing has become or is becoming standard practice for many container applications.
Another desirable configuration modification is the incorporation of one or more beads in the sidewalls of containers. Such beads can serve a number of useful functions, depending on their cross-sectional configuration and location on the sidewall.
For example, beads can increase the sidewall strength of a container, which is especially advantageous for containers fabricated from lightweight materials. As a result of the stronger sidewall, the container can withstand rough treatment in handling and transportation.
An outwardly projecting bead is also advantageous on containers having labels. For instance, if the outwardly projecting bead is placed at one or both ends of the container it can help prevent the label from sliding up or down along the longitudinal axis of the container. Additionally, by providing a recess for the label, the outwardly projecting bead can help protect the label when the container is rolled across a surface. These advantages can result in improved marketability and increased sales of the product packaged in the container.
Due to their method of manufacture, some containers will have different diameters at their two ends. For example, when a three-piece container is manufactured, it may have a flange and connected end piece at the bottom of the container which protrude laterally beyond the sidewall. On the other hand, the top flange and connected end piece may not laterally extend as far because the top may have been necked-in prior to flanging and attachment of the end piece. As a result of the different diameters at the two ends, the container will not roll straight on material handling equipment surfaces. An outwardly projecting bead placed near the top of the container can substantially equalize the diameters, thereby allowing the container to roll straight, easing and expediting the handling process.
It is known to form beads in a container sidewall by positioning opposing, mating die members adjacent to the interior and exterior surfaces of a container sidewall, and causing relative movement of the die members radially towards each other to bead the sidewall therebetween. For example, U.S. Pat. No. 4,487,048 by Frei et al. issued Dec. 11, 1984, discloses a method for beading the bodies of metal containers by rolling the container bodies between an inner tool and an outer tool, for instance, inner and outer mating rolls, in order to increase the container body sidewall strength. The inner tool has an expandable body and the container is rotated by rotating the inner tool after insertion and expansion within the container. The outer tool moves radially inward toward the inner tool to carry out the beading operation. Specifically, the outer tool is rolled upon the intermediately, radially inward disposed container body in order to force the container body to conform to the bead configuration of the mating surfaces.
It is believed that known beading methods have not been employed simultaneously with known container sidewall configuring processes which require relative axial (e.g. camming) movement between forming members positioned on opposing sides of a container sidewall. Additionally, it is believed that known beading devices cannot be successfully employed simultaneously or sequentially with such configuring processes to consistently form outwardly projecting beads at a desired location immediately adjacent to necked-in portions of container body sidewalls.
With particular respect to the present invention, it is known to vary the diameter of cylindrical objects, e.g. necking-in, by employing a spin forming process wherein the cylindrical objects are spun about their longitudinal axes while the sidewalls thereof are contacted by inner and/or outer forming members. U.S. Pat. No. 3,688,538 by Hoyne issued Sept. 5, 1972; U.S. Pat. No. 4,070,888 by Gombas issued Jan. 31, 1978; U.S. Pat. No. 4,563,887 by Bressan et al. issued Jan. 14, 1986; and U.S. patent application Ser. No. 858,774 by Bressan et al. filed May 2, 1986, now U.S. Pat. No. 4,781,047 issued Nov. 1, 1988, all disclose methods for necking-in cylindrical objects using spin forming methods. As indicated above, the necking-in of container bodies has or is becoming standard practice for many container applications. The above-referenced spin forming U.S. Pat. Nos. 4,563,887 and 4,781,047 are hereby incorporated by reference in their entirety. None of the spin forming references noted above disclose a method or apparatus for forming an outwardly projecting bead in the sidewall of a container before, during or after spin forming.
In view of the foregoing, it should be appreciated that it would be advantageous to consistently and reliably form outwardly projecting beads immediately adjacent to inwardly projecting, necked-in portions of container sidewalls. Further, it would be advantageous to form such outwardly projecting beads in the same operation during which the inwardly projecting, necked-in portions are formed. Additionally, it would be advantageous to form outwardly projecting beads in conjunction with a spin forming process.
SUMMARY OF THE INVENTION
The present invention provides a novel method and apparatus for forming an outwardly projecting bead in the sidewall of a cylindrical object. The invention may be employed in combination and simultaneously with known spin forming processes, and allows for precise positioning of beads relative to necked-in portions of container body sidewalls.
The method of the present invention includes the steps of supporting the interior side of the sidewall of a spinning cylindrical object and applying pressure to the exterior side of the sidewall. The interior support is provided adjacent the area where the outwardly projecting bead is to be formed. During the process pressure is applied to the exterior of the container sidewall at longitudinally and radially progressing locations on each lateral side of the inner support means. The longitudinal distance between such locations, together with the longitudinal width of the inner support means, substantially determines the longitudinal width of the bead to be formed. The means for providing pressure to the exterior side of the sidewall moves radially inward and longitudinally relative to the sidewall until, when the outwardly projecting bead forming process is complete, the pressure providing means is adjacent both lateral sides of the inner support means and also projects radially inward beyond the outer periphery of the inner support means. The radial distance that the exterior pressure providing means is located inward relative to the radially outermost portion of the inner support means is a major factor in determining the amount of outward projection of the resulting bead. Following the beading operation, the cylindrical object is released from between the inner support means and the outer pressure providing means. The shape and size of the bead may change slightly when the cylindrical object is released, depending upon the resiliency of the material out of which the cylindrical object is fabricated.
The novel apparatus of the present invention includes an inner forming member and an outer forming member. The inner forming member has a radially outwardly projecting peripheral forming surface which supports the interior of the sidewall during the forming process. The outer forming member includes a trailing support surface and a leading support surface for engaging and applying pressure to the exterior side of the sidewall, the two support surfaces being separated by a recess for receiving and restricting an outwardly projecting sidewall region. Means are provided to spin the cylindrical object about its longitudinal axis.
The method and apparatus of the present invention have a number of advantages. For example, an outwardly projecting bead can be formed in the sidewall of a cylindrical object immediately adjacent to a radially inwardly projecting necked-in portion. The relative positions of the outwardly projecting bead and the necked-in portion can be controlled with a high degree of accuracy. Additionally, an outwardly projecting bead and a radially inwardly projecting necked-in portion may be formed in a single spin forming operation.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a side view of a tooling arrangement for configuring cylindrical objects, including a preferred embodiment of the apparatus of the present invention;
FIG. 2 is a partial cross-sectional view of one embodiment of the inner and outer forming members of the present invention;
FIGS. 3 through 6 illustrate partial cross-sectional views of another embodiment of the inner and outer forming rolls, and also illustrate successive steps in the disclosed bead forming process;
FIGS. 7 through 9 show front plan views of three different container configurations in which an outwardly projecting bead has been formed immediately adjacent to a necked-in and flanged portion of an open end of a container.
DETAILED DESCRIPTION OF THE INVENTION
The apparatus and method of the preferred embodiment of the present invention will be described with reference to FIG. 1. In FIG. 1, a tooling assembly 20 is shown having an inner forming member 22 and an outer forming member 24. While the preferred embodiment is shown with respect to a container C having an open end disposed towards assembly 20 and a closed end, it should be appreciated that a container having both ends open could also be beaded in accordance with the present invention.
The outer forming member 24 is mounted for free rotation on a mandrel 26, and is able to slide axially along the mandrel 26 against the urgings of a coil compression spring 28 in reaction to longitudinal forces applied to the outer forming member 24 during the disclosed process. The mandrel 26 and outer forming member 24 supported thereon are interconnected with means for controlled movement toward and away from the longitudinal axis A of the container C, such as, for example, by a timed cam means.
The inner forming member 22 is mounted on a shaft 30 having a center axis B that is offset to one side of the axis A. Known means are provided for moving the shaft 30 and inner forming member 22 towards and away from the interior surface 34 of sidewall 36 of the container C. The inner forming member 22 is supported for free rotation about axis B and is restrained from axial movement. The inner forming member 22 has an outer peripheral forming surface 32 which, in operation, contacts and supports the interior surface 34 of the sidewall 36 of container C during the bead forming process.
Means are provided to support and rotate the container C about its longitudinal axis A. For example, the closed end of the container C can be supported by vacuum means or mechanical clamp means (not shown). The end of the container C closest to the assembly 20 is supported on a holder 38. The holder 38 is biased towards the inner forming member 22 by compression springs 40. During the configuring process the holder 38 may move in an axial direction away from the inner forming member 22, in response to longitudinal forces applied to holder 38 by the outer forming member 24. Either one or both of &:he holder 38 and support means provided at the other end of the container C can be driven to rotate, or spin, the container C about its longitudinal axis A.
The outer forming member 24 has a peripheral forming surface 56, a trailing support surface 42, an interfacing surface 50, and a recess defined by side surfaces 44 and 46 and bottom surface 48. As will be appreciated, the longitudinal width of the recess must be greater than the widest portion of the outer peripheral forming surface 32 of the inner forming member 22 that protrudes into the recess during the disclosed bead forming process. In addition to a peripheral forming surface 32, the inner forming member 22 may optionally include a trailing support surface 52. Preferably the outer forming member 24 and the inner forming member 22 have mating, sloped surfaces 50 and 54 in order to interface to form a necked-in portion on the container sidewall 36, adjacent to where the outwardly projecting bead is to be formed.
In use, a container C is mounted on the assembly 20 for rotation about the container's longitudinal axis A. Initially the peripheral forming surface 32 of the inner forming member 22 is brought into contact with the interior surface 34 of the spinning container C and rotates relative thereto. In certain applications, it may be desirable to begin the beading process by positioning the inner forming member 22 so that the outermost extent of the peripheral forming surface 32, and the interfacing container sidewall portion, extend beyond the plane initially defined by the adjacent sidewall region of container C prior to the start of the beading process. The outer forming member 24 is moved in a radial direction towards the container C. The outer peripheral nose 56 of the outer forming member 24 initially contacts the container C substantially opposite the peripheral forming surface 32 of the inner forming member 22. Such contact causes the outer forming member 24 to rotate about mandrel 26. As the outer forming member 24 continues radially inward, external pressure is applied to the sidewall 36. Furthermore, the opposing interface between the mating surfaces 54 and 50 on the inner forming member 22 and the outer forming member 24, respectively, squeezes, or restricts, the container sidewall therebetween and forces the outer forming member 24 in an axial direction towards the open end of the container C supported by holder 38.
The continued inward and simultaneous axially forward motion of the outer forming member 24 allows the support surface 42 of the outer forming member 24 to contact and apply external pressure to the container sidewall 36. The region of contact moves radially inward and axially towards the open end of container C. As the outer forming member 24 continues radially inward and axially forward, the portion of the container sidewall 36 which contacts the peripheral forming surface 32 of the inner forming member 22 is shaped by the peripheral forming surface 32. This outwardly projecting portion of the sidewall 36 protrudes into the recess of the outer forming member 24, which limits the outward projection to a desired longitudinal region of the sidewall 36, thereby forming an outwardly projecting bead therein. As will be appreciated, the dimensions of the recess must be such that the peripheral forming surface 32 can be accommodated therein during the entire, disclosed process. Although the figures show the recess to be substantially rectangular in shape, it can assume other shapes as well, as long as the outer peripheral forming surface 32 can be accommodated within the recess as the outer forming member 24 moves radially inward and axially forward. The limitation of the outward projection of the container sidewall 36 to a desired longitudinal region may be optionally further effected by causing the outer forming member 24 to move radially inward until the container sidewall 36 is rolled, or squeezed, between the support surface 42 of the outer forming member 24 and the optional trailing support surface 52 of the inner forming member 22. The process described above can be further understood by referring to FIGS. 3-6, which are discussed below.
As can be appreciated, an outwardly projecting bead can be formed in the sidewall of a container utilizing the present invention, while simultaneously necking-in an immediately adjacent portion of the container. Further, those skilled in the art will appreciate that the diameter and length of a bead can be selectively provided for by adjusting the relative dimensions of the above-discussed features of the inner forming member 22 and outer forming member 24.
FIG. 2 shows partial cross-sectional views of another embodiment of an inner forming member 122 and an outer forming member 124. The inner forming member 122 has a sloping radially inwardly projecting leading surface 154, a peripheral forming surface 132 and an optional trailing support surface 152. The outer forming member 124 has a peripheral forming surface 156, a radially inwardly sloping interfacing surface 150, a recess defined by the interfacing surface 150, sidewalls 144 and 146 and bottom wall 148, and a trailing surface 142. A portion of the trailing surface 142 can be shaped to provide a sloping trailing surface 142a to accommodate the inward angulation of the container body sidewall during the process of the present invention. The inward angulation results from the radially inward pressure applied to the exterior of the sidewall by the outer forming member 124.
FIGS. 3 through 6 show another embodiment of the inner forming member 222 and the outer forming member 224 at successive stages of the disclosed process. The members 222 and 224 are shown in partial cross-section. In FIG. 3 the inner forming member 222 has a radially inwardly sloping leading surface 254, an outer peripheral forming surface 232 and an optional trailing surface 252. The outer forming member 224 has a sloping foward surface 280, a peripheral forming surface 256, a radially inwardly sloping interfacing surface 250 which is configured to cooperate with the leading surface 254 of the inner forming member 222, a recess defined by interfacing surface 250, sidewalls 244 and 246 and bottom wall 248, and a trailing surface 242 having a sloping trailing surface portion 242a. FIG. 3 illustrates the positional relationship of the inner and outer forming members 222 and 224 as the outer forming member 224 initially contacts the exterior sidewall surface 290 of the container C.
In FIG. 4 the outer forming member 224 has moved radially inward to squeeze the container C sidewall between the sloping interfacing surface 250 of the outer forming member 224 and the sloping leading surface 254 of the inner forming member 222. The interface, or camming, of the two mating surfaces 250 and 254 forces the outer forming member 224 to move towards the open end of container C, thereby necking-in the container sidewall. Additionally, in the shown embodiment, the sloping forward surface 280 of the outer forming member 224 has interfaced with the sloping surface 284 of the holder 238 to initiate the spin forming of an outward flange in the sidewall portion therebetween.
FIG. 5 shows the outer forming roller 224 having further moved radially inward and axially towards the open end of the container C. In FIG. 5 the trailing surface 242 of the outer forming member has contacted the exterior sidewall surface 290 of the container C.
In FIG. 6 portions of the sidewall of container C have been forced radially inward by interfacing surface 250 and trailing surface 242 of the outer forming member 224. As a result, the outer peripheral forming surface 232 forms an outwardly projecting bead in the portion of the sidewall of container C located between surfaces 242 and 250 and contacted by peripheral forming surface 232. As shown in FIG. 6, the trailing surface 242 may optionally interface with the trailing surface 252 of the inner forming member 222, to squeeze the container sidewall therebetween. As can be appreciated, the rounded edge 292 between the wall 246 and trailing surface 242 of the outer forming member 224 will substantially define the lower boundary of the sidewall region in which the outwardly projecting bead is formed.
FIGS. 7, 8, and 9 illustrate three different configurations of outwardly projecting beads achievable with the present invention. In FIG. 7 an outwardly projecting bead is shown on a two-piece can, and in FIGS. 8 and 9 outwardly projecting beads are shown on three-piece cans. In these figures the innermost boundary of the outwardly projecting bead is shown as 60, 62 and 64. The radially outermost point on the outwardly projecting bead is shown as 70, 72 and 74. The transition region between the outwardly projecting bead and a necked-in region of the can is shown as 80, 82 and 84. A flange portion of the can is shown as 90, 92 and 94.
While various embodiments of the present invention have been described in detail, it is apparent that further modifications and adaptations of the invention will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention.
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A method and apparatus are disclosed for forming an outwardly projecting bead in the sidewall of a cylindrical object. The apparatus includes an inner forming member and an outer forming member having a leading forming surface, a trailing support surface, and a recess therebetween. The method includes forcing the sidewall of the container in a radially outward direction by applying a force to the inside of the sidewall, and limiting the resulting projection to a desired sidewall region to form an outwardly projecting bead in the container sidewall.
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This application is a continuation of co-pending Application No. 09/458,708, filed on Dec. 13, 1999, the entire contents of which are hereby incorporated by reference and for which priority is claimed under 35 U.S.C. §120; and this application claims priority of Application No. 1010798 filed in The Netherlands on Dec. 14, 1998 under 35 U.S.C. §119.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printing apparatus adapted to eject ink droplets from ink ducts, comprising at least one ink duct provided with an electromechanical transducer, a drive circuit provided with a pulse generator to energize the transducer, a measuring circuit for measuring an electrical signal generated by the transducer in response to the energization, and means to break the circuits in such manner that the drive circuit is open if the measuring circuit is closed.
2. Background Art
A printing apparatus of this kind is known from U.S. Pat. No. 4,498,088. In this printing apparatus, which is of the “drop-on-demand” type, the drive circuit applies an electrical pulse across the electromechanical transducer, more particularly a piezo element, so that the transducer is energized and generates a pressure wave in the ink duct. An ink droplet is ejected from the ink duct as a result. To guarantee reliability of such a printing apparatus, means are provided to detect breakdown of the ink duct, e.g. due to the presence of an air bubble in said duct. These means form part of a measuring system and comprise a measuring circuit with which it is possible to measure the resulting vibration in the ink duct after a pressure wave has been generated by the transducer. For this purpose, the transducer is used as a sensor: Thus, a vibration in the duct in turn results in the deformation of the electromechanical transducer, so that it generates an electrical signal. If air bubbles are present in the duct, this results in another vibration and consequently another electrical signal. A breakdown of an ink duct can thus be readily detected by measuring the electrical signal. A repair operation for the duct in question can then be carried out. One important disadvantage of a printing apparatus of this kind is that in order to check the condition of the ink ducts, the printing apparatus must leave the normal printing mode, i.e. the mode in which at least one ink duct ejects ink droplets for generating an image on a substrate, to pass to a measuring mode. In the measuring mode the transducer is energized so that the ink duct is vibrated but it is not possible to achieve ejection of an ink droplet from that duct. The resulting electrical signal is measured, and after this it is possible to determine whether there are any air bubbles in the ink duct. After the ink duct has been checked, the printing apparatus is returned to the printing mode, possibly after a repair operation has been carried out. The need to switch between a printing mode and a measuring mode results in a loss of productivity of the printing apparatus. Productivity will further fall with increasing reliability requirements for the printing apparatus, which means that the interval of time between the measuring modes has to be reduced. In addition to loss of productivity, the known printing apparatus has the disadvantage that two drive circuits provided with pulse generators are required for the transducer: one drive circuit to energize the transducer when the printing apparatus is in a printing mode, and a drive circuit to energize the transducer when it is in a measuring mode. This not only makes the printing apparatus expensive, but also, due to the increase in the number of components, less reliable.
SUMMARY OF THE INVENTION
The object of the present invention is to obviate the above-identified disadvantages. To this end, a printing apparatus has been invented wherein measurement of the electrical signal generated by the transducer in response to energization takes place when the printing apparatus is in a printing mode. There is therefore no need to interrupt the printing mode. The electrical signal is measured immediately after the transducer has been energized, the energization being such that an ink droplet is ejected with the duct operating as normal, in order to generate an image on a substrate. As a result there is no loss of productivity and in addition only one drive circuit is required for the transducer. An additional advantage is that the breakdown of the ink duct can be detected practically immediately, so that in many cases a repair operation can be carried out before any visible artefacts have appeared in an image. This means that a printing apparatus according to the present invention has a very high reliability. In one preferred embodiment the drive circuit and the measuring circuit are connected to the transducer via a common line serving as an input and output for electrical signals. This has advantages when the print-head is provided with a large number of ink ducts. The circuit can further be simplified by breaking the circuits by means of a changeover switch, so that the drive circuit is automatically opened as soon as the measuring circuit is closed. This changeover switch can be embodied by known electrical means but can also be integrated in the drive IC.
To check whether a vibration in the duct differs from a normal vibration, i.e. from a vibration when the duct is operating properly, the electrical signal generated by the transducer in response to energization can be compared with the electrical signal generated by a dummy element having the same impedance as the transducer in response to a comparable energization. Since, however, it is difficult to find a dummy element having in all circumstances exactly the same impedance as the transducer, it is preferable not to compare the electrical signal with a signal generated by a dummy element, but to characterize the electrical signal itself. For this purpose, at least one wave characteristic selected, for example, from the group comprising: amplitude, zero-axis crossing, frequency, phase and damping should be determined. It has been surprisingly discovered that in this way deviation in an ink duct can be detected with much higher accuracy. In this way it is possible to determine unambiguously what is the cause of malfunctioning of the ink duct (whether an air bubble, a solid particle clogging the duct, or a mechanical fault in the piezo element and so on) so that a repair operation can be accurately adapted to such cause.
In addition, a small deviation can be found which at that time is not yet affecting the ejection of ink droplets, for example an air bubble which is too small or still too far away from the opening of the ink duct to prevent ejection of an ink droplet. This enables preventive repair of an ink duct, so that generally there should be no artefacts appearing in an image. This is a considerable contribution to the reliability of the printing apparatus. In one preferred embodiment, a measured wave characteristic is compared with a reference value so that it is possible to determine easily whether a repair operation is required. In order further to increase the sensitivity of the measuring circuit, it can be provided with an amplifier. If an input of the amplifier is connected to the printing apparatus earth, stray capacitances (e.g. in the wiring) and leakage currents will also have hardly any effect on the measurement of the electrical signal generated by the transducer, so that the measurement accuracy further increases. In view of the simplicity of the measuring circuit in the printing apparatus according to the present invention, it is possible to provide a separate measuring circuit for all the transducers in the printing apparatus, even if there are several hundred. This makes it possible to check each duct, after an ink droplet has been ejected, for correct operation thereof, so that maximum reliability can be guaranteed.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
FIG. 1 is a diagram of the main components of a printing apparatus provided with ink ducts;
FIG. 2 is a diagram of an ink duct provided with an electromechanical transducer;
FIG. 3 is a block schematic of the electromechanical transducer, the drive circuit and the measuring circuit in a preferred embodiment;
FIG. 4 is a diagram showing how the circuits can be switched; and
FIG. 5 shows a number of electrical signals generated by a transducer according to the condition of the ink duct.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a printing apparatus provided with ink ducts. In this embodiment, the printing apparatus comprises a roller 10 to support a receiving medium 12 and guide it along the four printing heads 16 . The roller 10 is rotatable about its axis as indicated by the arrow A. A carriage 14 carries the four print-heads 16 , one for each of the colors cyan, magenta, yellow and black, and can be moved in reciprocation in the direction indicated by the double arrow B, parallel to the roller 10 . In this way the print-heads 16 can scan the receiving medium 12 . The carriage 14 is guided on rods 18 and 20 and is driven by suitable means (not shown). In the embodiment as illustrated in the drawing, each print-head 16 comprises eight ink ducts, each with its own outflow aperture 22 , said ducts forming an imaginary line perpendicular to the axis of the roller 10 . In one practical embodiment of a printing apparatus, the number of ink ducts for each print-head 16 will be many times greater. Each ink duct is provided with an electromechanical transducer (not shown) and associated drive circuit. In this way, the ink duct, transducer and drive circuit form a unit which can serve to eject ink droplets in the direction of the roller 10 . If the transducers are energized image-wise, then an image forms, built up from ink droplets, on the receiving medium 12 .
In FIG. 2, an ink duct 5 is provided with an electromechanical transducer 2 , in this example a piezo element. Ink duct 5 is formed by a groove in base plate 1 and is defined at the top mainly by piezo element 2 . At the end the ink duct 5 merges into an outflow aperture 22 formed by a nozzle plate 6 . When a pulse is applied across piezo element 2 by pulse generator 4 via the drive circuit 3 , said element generates a pressure wave in ink duct 5 so that an ink droplet is ejected from the outflow opening 22 .
FIG. 3 is a block schematic diagram of the electromechanical transducer 2 , the drive circuit 3 and the measuring circuit 7 in a preferred embodiment. Drive circuit 3 provided with pulse generator 4 , and measuring circuit 7 provided with amplifier 9 , are connected to piezo element 2 via a common line 15 . The circuits are opened and closed by changeover switch 8 . After a pulse has been applied across the piezo element 2 by the pulse generator 4 , element 2 in turn experiences a resulting vibration in the ink duct, and this is converted to an electrical signal by element 2 . If, after termination of the pulse, changeover switch 8 is switched so as to close the measuring circuit, the said electrical signal is discharged through the measuring circuit 7 . Amplifier 9 amplifies this signal which is fed via output 11 to an interpretation circuit (not shown), which if required may be followed by an action circuit (not shown).
FIG. 4 shows how the circuits 3 and 7 could be switched. During a drive period A the drive circuit 3 is closed so that piezo element 2 can be energized. After energization has taken place, a measuring period M starts, in which measuring circuit 7 is closed via changeover switch 8 and drive circuit 7 is opened. After expiration of measuring period M, in which the electrical signal generated by piezo element 2 is measured, the drive circuit is closed and a new drive period A starts. Of course there are many variants of this switching procedure. For example, a measuring period M could also follow after the piezo element has been energized a number of times in a drive period. In an embodiment in which very high reliability is required, each duct could be checked after each pulse. If a repair operation is necessary, it can be restricted to the duct in which the malfunctions occur. Of course, it is possible to check the functioning of an ink duct during the repair operation as well and to stop this operation as soon as the duct operates properly again. If reliability is less important, it could be decided, for example, to check one jetting duct for each jet pulse. It would also be possible to check a duct after a fixed number of ejected ink droplets or after a specific interval of time.
FIG. 5 shows a number of electrical signals as generated by a transducer in response to a pressure wave in an ink duct, dependent on the state of said ink duct. If an ink duct is operating properly, the result is a damped sinusoidal electrical signal as shown by Curve 1 . For a given ink duct geometry, the presence of an air bubble results in an electrical signal as shown in Curve 2 . This signal has a higher frequency, higher initial amplitude and weaker damping. If a duct is (partially) closed by a solid particle, then for the same duct geometry this results in an electrical signal having a lower frequency, smaller initial amplitude and stronger damping as shown in Curve 3 . Finally, Curve 4 is an example of an electrical signal measured in the case of a specific mechanical deviation of the piezo element.
It will be apparent from the foregoing that the cause of the malfunctioning of an ink duct (or the expected malfunctioning) can be accurately determined in a printing apparatus according to the present invention so that it is possible to adapt the repair operation to such cause.
The measurement can be used, for example, to check the operation of the individual ducts after production of a print-head provided with one or more such ducts. If errors have occurred in production, e.g. a layer of glue that has worked loose, a scratch in a wall of a duct, a faulty piezo element etc., these faults are recognized and can be repaired if possible.
In the case of a printing apparatus in use, the measurement can be used to check the state of the ink ducts (continuously) without any loss of productivity. The high accuracy with which irregularities in an ink duct can be detected even makes it possible to carry out preventive repairs on ducts, i.e. before there is any question of failure of an ink duct.
In a preferred embodiment of the printing apparatus, one or more wave characteristics of the electrical signal as shown in FIG. 5 are compared with a set of reference values which in a practical embodiment are provided with top and bottom limits within which a wave characteristic of a normally operating duct should be located. The reference values can be determined in many ways, but this is not an essential part of the invention. For example, the reference values can be determined after completion of the production process of a print-head. In addition, the reference values could be determined when the printing apparatus is in operation, by taking the average over a large number of pulses. In this way it is possible to adapt these values continuously, so that, for example, (slow) wear processes in the print-head have no adverse influence on the measurement. It is also possible to compare the wave characteristics of an individual duct with those of one or more (neighboring) ducts.
The invention is not limited to the embodiments described. Modifications can easily be made by one skilled in the art. For example, the required reliability in relation to the productivity of the printing apparatus depends, inter alia, on the way in which the reference values are determined, and whether this is carried out for each individual duct or for all the ducts together, how far apart the top and bottom limits of the reference value are situated, how many wave characteristics are determined to establish the condition of a duct, and so on.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
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A printing apparatus including at least one ink duct provided with an electromechanical transducer, a driver circuit provided with a pulse generator and operatively associated with the transducer to energize the transducer, a measuring circuit operatively associated with the transducer for measuring an electrical signal generated by the transducer in response to energizing by the pulse generator, a device for breaking the circuits in such a manner so that when the drive circuit is open, the measuring circuit is closed, wherein measurement of the electrical signal takes place when the printing apparatus is in a printing mode.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International Application No. PCT/GB2004/001598 filed Apr. 13, 2004, the disclosures of which are incorporated herein by reference, and which claimed priority to Great Britain Patent Application No. 0308912.5 filed Apr. 17, 2003, the disclosures of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to improvements in signal apparatus for a vehicle, especially but not exclusively for signalling the intent of a driver during a lane change manoeuvre on a highway.
[0003] A lane change on a highway having multiple lanes such as a motorway or dual carriageway requires the use of an indicator by the driver during the lane change. The indicator, usually a lamp that can produce a flashing amber light visible at the side of the vehicle in which the driver wants to turn, warns other drivers that the vehicle is changing lane. After a lane change manoeuvre is complete the driver must cancel the indicator, as a self-cancelling mechanism will not operate during such a manoeuvre in many situations. Often drivers forget to cancel the indicator, which can prove annoying to other drivers.
[0004] Some attempts have been made to overcome this problem using a timer to cancel the indicator after a predetermined time or number of flashes of the indicator. This does not provide a satisfactory solution, as the driver may not have completed the manoeuvre in the predetermined time.
BRIEF SUMMARY OF THE INVENTION
[0005] According to a first aspect, the invention provides a signal apparatus for a vehicle having at least one input at which signals are received from components associated with the vehicle, the received signals comprising an indication demand signal initiated by a driver of the vehicle and a lane detection signal produced by a lane detection apparatus indicative of the position of the vehicle relative to a lane of a highway, and a processing means which is arranged to produce an indication signal that is dependent upon both the indication demand signal and the lane detection signal.
[0006] The processor may be arranged to produce the indication signal following receipt of an indication demand signal and cancel the indication signal when the lane detection signal indicates that the vehicle is at an appropriate position relative to the lanes of the highway. The vehicle may be considered to be at an appropriate position relative to the lanes by determining the heading angle of the vehicle relative to the lane. Most preferably, it is considered appropriate to cancel when the vehicle is going straight ahead in the lane, i.e. by checking that the vehicle is at a heading angle of approximately zero degrees relative to the heading of the lane.
[0007] Checking the heading angle allows a vehicle to cross multiple lanes without the indicator auto-cancelling the cancellation only occurring at the end of the manoeuvre when the vehicle is travelling straight along its lane.
[0008] The processing means may cancel the indication signal by cancelling the indication demand signal, i.e. returning it to it original state prior to the driver initiated demand. Alternatively, a cancel signal may be produced which is combined with the indication demand signal to produce the indication signal. The combination may be by way of a logical operation, perhaps by passing both through an AND gate.
[0009] The processing means may be adapted to produce an indication demand signal after a driver initiated demand which continues even after a driver has indicated that the indication signal should be cancelled. This would prevent a driver cancelling a signal before a lane change has been completed.
[0010] The processing means may learn over time whether or not the indication should be cancelled after the driver has demanded that it is cancelled. For example, where a driver persistently cancels the indication before a lane change is completed, the processing means may learn this driver behaviour. On all subsequent operations of the indicator a time delay may be applied which is equal to the average time delay between a driver cancelling the demand signal and the vehicle completing the manouevere as determined from the lane detection signal.
[0011] Producing an indication signal that is dependent on both the indicator demand signal and a lane change signal allows the indicator to be cancelled when a manoeuvre has been completed. In this way, the driver no longer needs to remember to cancel the indicators. It also permits an indication to be cancelled at the correct time even if the vehicle changes lanes within a bend.
[0012] The processing means may comprise an electronic circuit such as an ASIC. It may, alternatively, be distributed across a multiple of electronic circuits, possibly connected across a bus or wiring loom of a vehicle. The processing means may therefore be distributed around the vehicle.
[0013] According to a second aspect, the invention provides a signal apparatus which includes: a turn signal indicator, which illuminates in response to an indication signal; an indicator switch, which is operable by a user to produce an indication demand signal; a lane detection apparatus, which produces a lane detection signal indicative of the position of a vehicle relative to the lanes of a multi-lane highway; and a processor, which references the indication demand signal with the lane detection signal to generate an indication signal.
[0014] The indication signal produced by the processor may activate the turn signal following receipt of an indication demand signal and cancel the indicator when the vehicle is at an appropriate position relative to the lanes of the highway as indicated by the lane detection signal.
[0015] The lane detection apparatus may include a camera, which is located on the vehicle such that a portion of the highway in front of the vehicle is included within its field of view. An example of such an apparatus is known from our earlier International Patent Application number PCT/GB02/02324, published under publication number WO02/092375, the disclosures of which are incorporated by reference herein.
[0016] The indicator switch may comprise a stalk, which is located close to the steering wheel of a vehicle for operation by a driver as is known in the prior art. It may produce an indication demand signal which changes state when the driver moves the stalk. The stalk may include a latch, which holds the output of the switch in either a rest state or a demand state when operated by the driver.
[0017] The processor may be arranged to cancel the indication signal regardless of whether the indicator is in the rest or the demand positions.
[0018] The indication signal may in a simple arrangement comprise a flag, which is raised by the processor when an indication is needed and lowered when it is not needed.
[0019] According to a third aspect the invention provides a method of operating an indicator of a vehicle during a lane change manoeuvre comprising initiating the indicator when an indication demand signal is received from an indicator switch and cancelling the indicator when a signal from a lane detection apparatus indicates that the vehicle has reached an appropriate position relative to the lanes of the highway.
[0020] The method may also cancel the indicator when a cancel signal is received without waiting for the lane signalling apparatus to indicate that the appropriate position has been reached. Such a signal may be received if a driver of the vehicle operates the indicator switch to cancel the indicator.
[0021] Other advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 shows a side view of a vehicle fitted with a signal apparatus according to the present invention;
[0023] FIG. 2 shows a view from the interior of the vehicle of FIG. 1 , forwards through the front window showing the road ahead; and
[0024] FIG. 3 shows a flowchart depicting the method carried out in the signal apparatus of FIGS. 1 and 2 .
DETAILED DESCRIPTION OF THE INVENTION
[0025] The vehicle 1 shown in the accompanying drawings is fitted with a set of indicators, of which only the front left indicator 116 is shown. These are mounted in the usual fashion at each corner of the vehicle and are arranged to be illuminated in sets, with each set comprising the indicators on the left or right hand side of the vehicle 1 .
[0026] In order to control the indicators 116 , an indicator stalk 108 is provided in the region of steering wheel 106 . This is of the common design where the driver of vehicle 1 signals a demand for illumination of the indicators 116 of one set or the other by pushing the indicator stalk 108 up or down for (in the example shown in FIG. 2 of the accompanying drawings where the indicator stalk 108 is mounted on the left hand side of the steering wheel 106 ) left or right sets respectively. The indicator stalk 108 latches in position once pushed and can be reset by the driver overriding the force of the latch or by the latch being released. In an alternative embodiment, the demand for indication is stored electronically by raising or lowering one or more flags and in which case a latch is not needed and a simple tap-up tap-down switch may be used.
[0027] An icon 112 is provided on dashboard 110 in view of the driver, which lights to indicate illumination of the indicators 116 and hence remind the driver that they are indicating. Indicator control means 104 detects the indictor demand and flashes the relevant set of indicators in the usual manner.
[0028] The vehicle is also fitted with a video camera 100 mounted behind front window 114 , which captures images of the view of the road ahead of the vehicle 1 . This is coupled to a lane detection apparatus 102 , which analyses the captured images to detect lane boundaries such as those at the edge 120 of the road 121 or those separating lanes 122 . The lane detection apparatus 102 fits the lane markings to a curve and uses this to calculate the heading angle and offset of the vehicle 1 relative to the lane boundaries 120 , 122 .
[0029] Although the indicator control means 104 and lane detection apparatus 102 are depicted as separate entities, the skilled man will envisage that these could be combined into one module, or one or more of the control means 104 and lane detection apparatus 102 could be combined into modules controlling other vehicle functions.
[0030] The indicator control means 104 also acts to cancel the flashing of the indicators 116 once a lane change has been completed. It does this by releasing the latch of the indicator stalk 108 , hence cancelling the driver's demand for indication. The method that the control means 104 uses to determine whether to cancel the driver's demand is shown in FIG. 3 of the accompanying drawings.
[0031] In a first step 200 , the control means checks whether the driver has demanded indication by use of the indicator stalk 108 . If not, then the control means need take no further action other than to ensure the icon 112 has been extinguished 208 . The method then repeats back to the first step 200 .
[0032] If the driver has demanded indication, the control means 104 checks 202 whether the vehicle 1 has moved to the centre of the next lane. It does this by checking the offsets from lane boundaries measured by lane detection apparatus 102 . The vehicle 1 is determined to have changed lane once it is roughly (typically within percent) in equidistant from the lane boundaries of the next lane in the indicated direction. Until this happens, the method is restarted from first step 200 to check whether the driver is still demanding an indication.
[0033] Once the control means 104 has determined that the vehicle 1 is in the correct lane, it checks 204 whether the vehicle 1 is straight in the lane. It does this by checking that the vehicle 1 is at a heading angle of approximately zero (typically within a range of 5° from zero) with respect to the lane boundaries of the new lane. This check is repeated until the vehicle 1 is straight in the lane.
[0034] Once the vehicle 1 is straight, the indication may be cancelled 206 . The latch is released, although in an alternative embodiment the indicator stalk 108 may be driven into the cancelled position by a solenoid or other actuator or, in the case where the demand is stored electronically, the demand flag may be cleared. The indicator icon 112 is extinguished 208 and the method returns to the first step 200 where the control means 104 waits for the driver to indicate a demand.
[0035] In a further alternative, the control means 104 records if the driver cancels the demand before the method described above would have done. If the driver consistently does this, the control means may adjust when the method cancels the demand 206 by expanding the ranges of the lane offsets and heading angles in which the vehicle 1 is determined to be straight ahead in the appropriate lane. This is subject to a maximum limit from central in the lane and within a predetermined degrees of straight-ahead.
[0036] In accordance with the provisions of the parent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this inventiono may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.
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A signal apparatus for a vehicle having at least one input at which signals are received from components associated with the vehicle. The received signals comprise an indication demand signal initiated by a driver of the vehicle and a lane detection signal produced by a lane detection apparatus indicative of the position of the vehicle relative to a lane of a highway. A processing means is arranged to produce an indication signal that is dependent upon both the indication demand signal and the lane detection signal.
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FIELD OF INVENTION
[0001] This Invention relates to golf clubs and particularly to an improved golf club head that will enable the golfer to swing the golf club so that the club head has a greater velocity (as compared with the velocity of a generally similar conventional golf club). The present invention relates to club head velocity enhancement.
DESCRIPTION OF THE RELATED ART
[0002] FIGS. 1 and 2 of the attached drawings show a golf club having a club head of generally conventional construction (or shape). During a golf ball-striking event the club head is swung in an arc from a starting position in which the club head is above and slightly behind the golfer's head. The club head travels in an arc angularly downwardly and then in front of the golfer's upright body so as to come into forcible contact with a stationary golf ball located at or slightly above ground level.
[0003] The club head continues the arcuate movement to an elevated point away from the golfer's body, while the golf ball is propelled forwardly from the ball-striker face of the club head. The golf ball travel distance is generally proportional to the club head velocity at the moment when the club head makes contact with the ball; i.e. a higher club head velocity at the ball contact moment will generally produce a desirably longer ball travel.
[0004] One obstacle to a higher club head velocity is the air resistance or turbulence associated with arcuate travel of the club head from the starting (elevated) position to the ball contact position (at or near ground level). FIG. 1 of the attached drawings shows generally how the club head disturbs the air as it travels in a right-to-left direction. The airstream flow lines (with arrows) are relative to the club head, which is moving in an absolute sense, so that air in area 20 on the front face of the club is pressurized to force the air outwardly and then around the club head side surfaces. At some point (or plane) the air separates from the club head to form a low pressure wake area 24 behind the trailing surface 16 of the club head. In FIG. 1 of the drawings the air separation point (or plane) is designated by numeral 11 .
[0005] The low pressure wake area exerts a suction effect on the club head, to reduce the club head velocity. At the same time the pressurized area 20 proximate to the front face 14 of the club head also has a retarding (or reducing) effect on the club head velocity. To sum up, the suction effect of suction wake area 24 and the pressurizing effect in area 20 are additive to provide a total air resistance contributing to an undesired loss of club head speed. The present invention concerns an air passage system designed to reduce the total air resistance that contributes to an undesired loss of club head speed.
SUMMARY OF THE INVENTION
[0006] The invention involves a golf club head having one or more air passages extending from the front face of the club head to the trailing face of the club head, so that during a ball-striking event some of the air in front of the club head is transferred through the passage(s) to the wake area behind the club head. This transfer of air partially reduces the air pressure in front of the club head while at the same time raising the air pressure in the low pressure wake area behind the club head. The net effect of this air transfer is to reduce the air resistance to club head movement, thereby promoting a faster club head speed and greater golf ball travel distance.
BRIEF DESCRIPTION OF THE DRAWING
[0007] FIG. 1 is a top plan view of a conventional golf club head, showing the relative air flow pattern around the club head during a golf ball-striking event, i.e. while the golfer is swinging the golf club to drive the golf ball down the fairway.
[0008] FIG. 2 is a front view of the FIG. 1 golf club head, taken in a direction looking toward the club head front face 14 .
[0009] FIG. 3 is a top plan view of a golf club head embodying the present invention.
[0010] FIG. 4 is a front view of the FIG. 3 golf club head.
[0011] FIG. 5 is a sectional view of the FIG. 3 golf club head, taken on line 5 - 5 in FIG. 3 . A conventional golf ball is shown in phantom, in front of the club head.
[0012] FIG. 6 is a top plan view taken in the same direction as FIG. 3 , but showing another form that the invention can take.
[0013] FIG. 7 is a front view of the FIG. 6 construction.
[0014] FIG. 8 is a sectional view taken on line 8 - 8 in FIG. 6 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Before describing the golf club of the present invention, it is believed that a better understanding of the invention can be realized by first describing the conventional prior art golf club, as shown, e.g., in FIGS. 1 and 2 . The conventional golf club comprises a club head 10 attached to a conventional shaft 12 . The club head has a ball-striker front face 14 , a convex curvilinear rear face 16 , and side surfaces 17 extending rearwardly from the peripheral edges of front face 14 to merge smoothly with curvilinear rear face 16 . As shown in FIG. 1 , side surfaces 17 taper in a direction from the front face to the rear face, so as to promote (as much as possible) a smooth air flow relative to the club head. The flow is “relative” since the club head is moving in a right-to-left direction, while the air is essentially stagnant except for air that is momentarily displaced by passage of the club head. Numeral 22 generally designates the relative air stream components, particularly the displaced air stream elements.
[0016] Air in zone 20 proximate to the club head front face 14 is pressurized by the advancing club so as to offer some resistance to continued club head motion. Air in the path of the club head is displaced outwardly by pressurized air in zone 20 to points beyond the peripheral edges of front face 14 , as indicated by numeral 22 A. The displaced air than collapses back toward the club head side surfaces 17 to flow, as much as possible, along those surfaces. Numeral 22 B designates the collapsing air.
[0017] At some point the air separates from side surfaces 17 to form a low pressure wake area 24 proximate to curvilinear rear face 16 . Numeral 11 designates generally the imaginary separation plane, i.e. the point(s) where the boundary air layer on surfaces 17 can no longer control or hold the main air stream on the club surface. In actuality, the rear surface 16 of the club head is moving so fast in a right-to-left direction that the air cannot collapse toward the club head centerline 19 rapidly enough to keep pace with club head movement. Rear face 16 tends to produce a vacuum in wake area 24 , thereby generating turbulence that prevents the collapsing air from attaching to surface 16 .
[0018] It will be seen that resistance to club head motion in a right-to-left direction is provided by the pressurized air condition in zone 20 plus the low pressure suction condition in turbulent wake area 24 . The result is an undesired loss of club head speed.
[0019] FIGS. 3 through 5 shows a club head of the present invention designed to reduce air resistance to club head movement. The club head is similar to the conventional club head depicted in FIG. 1 except that an air passage means is provided in the club head to transfer air from pressurized zone 20 to wake area 24 . The effect is to reduce the pressure in zone 20 and simultaneously increase the air volume in wake area 24 (thereby reducing the suction effect on club rear face 16 ).
[0020] The air passage means comprises a first slot-shaped air passage 30 having an entrance opening proximate to upper edge 32 of the club front face 14 and a second slot-shaped air passage 30 having an entrance opening proximate to lower edge 34 of the club front face 14 . Front face 14 can be defined by a metal place 28 having a relatively hard ball-striker surface (face). Each air passage 30 extends from front face 14 entirely through the club head body to form an exit opening 33 in curvilinear rear face 16 . Motion of the club head in a right-to-left direction provides the motive force for transferring air from pressurized zone 20 through air passages 30 into depressurized wake area 24 . The net effect is to reduce the air resistance to club head motion, thereby facilitating an increased (enhanced) velocity for a greater ball travel distance.
[0021] FIG. 5 shows, in phantom, a golf ball 36 in the path of the club head just prior to being stuck. Passages 30 are spaced apart by a distance that approximates the golf ball diameter. Face 14 of the club head has an optimal ball-strike point 18 ( FIG. 4 ) that is designated by the golf club designer as the ball strike point that will produce the greatest ball travel distance for a given input force. Strike point 18 is located half way between the two air passages 30 , such that when the ball is struck in the intended fashion the ball does not come into contact with either passage entrance opening. Each entrance opening is spaced from strike point 18 by a substantial distance that is approximately equal to the golf ball radius, such that the ball can contact face 14 above or below optimal strike point 18 without engaging either passage 30 .
[0022] Each exit opening 33 is located in an area of curvilinear rear face 16 that communicates with wake area 24 , so that air exiting each passage immediately raises the pressure in wake area 24 , thereby reducing wake area turbulence and minimizing the suction effect on rear face 16 .
[0023] FIGS. 6 through 8 show another form that the invention can take. In this case the air passage means comprises a series of separate circular cross-section air passages 30 A and 30 B, each spaced a substantial distance from optimal strike point 18 . Passages 30 A have entrance openings located near the upper edge of front face 14 . Passages 30 B have entrance openings located near the bottom edge of front face 14 . As shown, each passage has a circular cross section. However other cross sectional shapes could be used, e.g. oval. Preferably the cross section should be “corner free” in order to avoid flow losses associated with such corners. Each passage 30 A or 30 B extends from face 14 through the club body to rear face 16 , so that during a ball-striking motion air in the path of the club head is transferred from the pressurized zone 20 to the depressurized wake area 24 . The net effect is to reduce air resistance and increase club head velocity (as more particularly described in connection with FIGS. 3 through 5 ).
[0024] As best shown in FIG. 8 , each air passage is defined by a sleeve 39 formed separately from the club head body. Each sleeve is formed of a high strength material (e.g. titanium) so as to reinforce the club head against structural failure, e.g. splintering or deformation.
[0025] While specific forms of the invention are shown in the drawings, it will be appreciated that some variations and alternate designs can be used while still practicing the invention.
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A golf club includes a club head that has one or more air passages extending from its front face to its rear face, so that when the club is swung in a ball-striking action air in the path of the club head is transferred from a pressurized zone on the head front face through the air passages into a low pressure wake area behind the club head. The air transfer action minimizes resistance to club movement, so as to contribute to a faster club head speed and a longer ball travel.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention disclosed in this specification relates to a doping method using an ion doping apparatus which does not require mass separation of generated ions and a method of manufacturing a field effect transistor using the doping method.
[0003] 2. Description of the Related Art
[0004] In a manufacturing process of a semiconductor element such as a field effect transistor, when a donor impurity or an acceptor impurity is added into a processing object such as a semiconductor film formed over a substrate having an insulating surface or a semiconductor substrate, an ion implantation apparatus or an ion doping apparatus is used. An ion implantation apparatus is a mass-separation type apparatus in which an unnecessary ion species can be separated by using a mass separator and in which a processing object placed in a treatment chamber can be subjected to only a desired ion species. Therefore, the dose amount of a desired ion species can be precisely controlled.
[0005] On the other hand, since a mass separator is not included in an ion doping apparatus, the ion doping apparatus is a non-mass-separation type apparatus in which a processing object placed in a treatment chamber is irradiated with all ions included in an ion beam (hereinafter- referred to as total ions in this specification) which is extracted from plasma generated in an ion source. Accordingly, the doze amount is counted by not only a desired ion species but also total ions including an unnecessary ion species, which makes it difficult to precisely control the doze amount of a desired ion species.
[0006] Hereinafter, an ion implantation apparatus refers to an apparatus with a mass separator, and an ion doping apparatus refers to an apparatus without a mass separator in this specification.
[0007] As a source gas, for example, PH 3 (phosphine) diluted with hydrogen is used in a case of using phosphorus as a donor, and B 2 H 6 (diborane) diluted with hydrogen is used in a case of using boron as an acceptor. In an ion source, the source gas is separated into positive ions and electrons; in other words, the source gas is ionized to generate plasma. Then, an ion beam is extracted from the plasma. Since the source gas includes hydrogen as described above, a large amount of hydrogen ions is included in the generated plasma. This hydrogen ion is an unnecessary ion species.
[0008] Since the dose amount is counted by total ions including the hydrogen ions in the ion doping apparatus, a proportion of a desired ion species in total ions is varied depending on a condition of plasma even if the dose amount of total ions is not changed. In this case, the dose amount of only a desired ion species is forced to change.
[0009] In addition, the precise control of a concentration of boron in a semiconductor substrate or a semiconductor film is required in doping a portion where a channel region is formed with boron as an impurity at a low concentration, that is to say, in channel doping, in order to control a threshold voltage V th of a field effect transistor. However, the ion implantation apparatus is sometimes used only in a step of channel doping since the precise control is difficult to be performed with the ion doping apparatus.
[0010] Among the ion doping apparatuses, there is an ion doping apparatus including a mass spectrometer. By using the mass spectrometer, a proportion of a desired ion species can be monitored. However, when doping of boron at a low concentration is performed as in the case of channel doping, there is a problem in which ions of a compound including boron, in other words, a desired ion species is not detected by the above mass spectrometer.
[0011] The invention described in Reference 1 focuses on that a peak with high intensity due to H 3 + ions is observed by using a mass spectrometer (referred to as E×B) equipped in an ion doping apparatus, even in such a condition in which doping is performed with an impurity at a low concentration (Reference 1: Japanese Patent Laid-Open No. 2004-39936). In other words, the invention attempts to control the dose amount of boron by finding a correlation between the peak intensity due to H 3 + ions and a concentration of boron in a processing object, which has been measured by SIMS (secondary ion mass spectrum) analysis.
[0012] However, it is found that even when the invention described in Reference 1 is used, a concentration of boron in the processing object is not stable and the variation is not small in the condition of doping with an impurity at a low concentration. Since the dose amount of boron cannot be controlled precisely, the improvement of the above invention is required.
SUMMARY OF THE INVENTION
[0013] It is an object of the present invention disclosed in this specification to control a concentration of a donor impurity or an acceptor impurity in a processing object after doping, by a method different from that of the invention described in Reference 1 and reduce the variation of the concentration thereof. Further, it is an object to reduce a variation of a threshold voltage of a field effect transistor, for example, a thin film transistor, and control a voltage so as to be in a predetermined range.
[0014] One feature of the invention disclosed in this specification is to include a step of obtaining a dose amount D 1 of total ions required to obtain a peak concentration Y correspondingly to a change of a proportion X (0<X<1) of ions from a first relational expression. The proportion X is a proportion of the ions of a compound including a donor impurity or an acceptor impurity in total ions, which is measured from mass spectrum. The peak concentration Y is a peak concentration of the donor impurity or the acceptor impurity in a processing object doped with the donor impurity or the acceptor impurity. The first relational expression is a relational expression of the proportion X and the peak concentration Y. The invention also includes a step of doping a processing object with the donor impurity or the acceptor impurity by an ion doping apparatus in a condition in which a source gas used in the doping is used, a dose amount of total ions is set at a value obtained in the step, and an acceleration voltage is a same value as that of the doping.
[0015] One feature of the invention disclosed in this specification is to include a step of obtaining a dose amount D 1 of total ions required to obtain a threshold voltage Vth correspondingly to a change of a proportion X (0<X<1) of ions from a first relational expression and a second relational expression. The proportion X is a proportion of the ions of a compound including a donor impurity or an acceptor impurity in total ions, which is measured from mass spectrum The threshold voltage Vth is a threshold voltage of a field effect transistor manufactured by using a processing object which is doped with the donor impurity or the acceptor impurity. The first relational expression is a relational expression of the proportion X and a peak concentration Y of the donor impurity or the acceptor impurity in the processing object doped with the donor impurity or the acceptor impurity. The second relational expression is a relational expression of the threshold voltage Vth and the peak concentration Y. The invention also includes a step of doping a processing object with the donor impurity or the acceptor impurity by an ion doping apparatus in a combination in which a source gas used in the doping is used, a dose amount of total ions is set at a value obtained in the step, and an acceleration voltage is a same value as that of the doping.
[0016] In a case of heavy doping using a source gas in which a compound of a donor impurity or an acceptor impurity is diluted with hydrogen to 5% to 40%, which is a first concentration, a peak due to ions of the above compound including the impurity as well as a peak due to hydrogen ions is observed by a mass spectrometer equipped in an ion doping apparatus to be used. The above-described compound of the acceptor impurity is, for example, B 2 H 6 , and the above-described compound of the donor impurity is, for example, PH 3 . In a case of using B 2 H 6 , B 2 H y + ion (y is a positive integer) can be given as a main ion of a compound including the above impurity. The first concentration is calculated from a flow ratio of a compound of a donor impurity or an acceptor impurity included in a source gas to the source gas. The same can be applied to a second concentration to be described later. The flow ratio can be translated into a volume ratio.
[0017] In the heavy doping, a peak due to ions of a compound including a donor impurity or an acceptor impurity and a peak due to hydrogen ions can be observed by the above mass spectrometer. The number of the each peak is not limited to one. A plurality of peaks may each be observed. A proportion X (0<X<1) of the ions of the compound including the impurity included in total ions can be obtained from a ratio of a peak intensity of the ions of the compound including the above impurity to the sum of the peak intensities. For example, when peaks of H + ions, H 2 + ions, H 3 + ions, and B 2 H y + ions (y is a positive integer) are observed and an intensity ratio of the above peaks is 10:5:100:50, a proportion X of the B 2 H y + ions is 0.30. This is obtained by dividing 50 by 165, which is the sum of 10, 5, 100, and 50.
[0018] As a diluent gas included in the above source gas, a rare gas such as helium or argon may be used instead of using hydrogen.
[0019] In the above heavy doping, even when the dose amount of total ions is constant, a proportion X of the ions of the compound including a donor impurity or an acceptor impurity included in total ions is varied. This is because the state of plasma generated in an ion source in an ion doping apparatus is varied in accordance with time; in other words, this is because the plasma state is not stable over a long period.
[0020] After obtaining the proportion X of the above ions, a source gas is used, in which the above compound of a donor impurity or an acceptor impurity is diluted with hydrogen to a second concentration equal to or lower than the first concentration, and a processing object is doped with the above donor impurity or the acceptor impurity at a predetermined acceleration voltage without changing the ion doping apparatus to be used. At that time, a dose amount of total ions D 0 (cm −2 ) is needed to be measured. The second concentration may be 5% or more. For example, when the first concentration is 15%, the second concentration can be 7.5%. As a diluent gas contained in the source gas, a rare gas such as helium or argon may be used instead of using hydrogen.
[0021] The processing object is a target object to be doped, such as a semiconductor film formed over a substrate having an insulating surface or a semiconductor substrate. This doping is done, for example, for a case of channel doping where the concentration or the dose amount is set to a condition of channel doping.
[0022] Then, a peak concentration Y (cm −3 ) of a donor impurity or an acceptor impurity in the processing object is analyzed by an analysis method such as SIMS (secondary ion mass spectrum) analysis. The peak concentration is a maximum value of the concentration of a donor impurity or an acceptor impurity in a profile, in which the horizontal axis shows a depth of a donor impurity or an acceptor impurity from a surface of the processing object and in which the vertical axis shows a concentration of the above impurity. In the plasma state in which a proportion X of ions of a compound including a donor impurity or an acceptor impurity is obtained, since the peak concentration Y of the donor impurity or the acceptor impurity in the processing object is varied depending on the value of X, the following relational expression, which is referred to as Formula 1, can be obtained: Y=aX+b (a and b are real numbers).
[0023] The Formula 1 can be employed only when the dose amount of total ions is specific value, in other words, D 0 , in conducting a doping process to the processing object by an ion doping apparatus. Regarding an arbitrary dose amount D 1 (cm −2 ) of total ions, a following relational expression, which is referred to as Formula 1′, can be obtained: Y=(D 1 /D 0 )(aX+b). Note that D 1 /D 0 shows a fraction in which D 0 is a denominator and D 1 is a numerator.
[0024] From the Formula 1′, the dose amount D 1 of total ions corresponding to a desired value of a peak concentration Y of a donor impurity or an acceptor impurity can be obtained. The dose amount D 1 can be obtained by an electronic calculator. The dose amount of total ions is adjusted to be the above obtained value, and doping is performed to a processing object without changing the other conditions.
[0025] On the other hand, a threshold voltage V th (V) of a field effect transistor formed through the above doping step to the processing object is varied depending on the peak concentration Y obtained by the analysis method such as SIMS analysis or the square root of the peak concentration Y. Accordingly, a following relational expression, which is referred to as Formula 2, can be obtained: V th =cY+d, or V th =cY 1/2 +d (c and d are real numbers).
[0026] By assigning Formula 1′ to Formula 2, a relational expression, V th =c(D 1 /D 0 )(aX+b)+d, or V th =c(D 1 /D 0 ) 1/2 (aX+b) 1/2 +d, can be obtained. Accordingly, a dose amount D 1 of total ions corresponding to a desired threshold voltage V th can be obtained. This dose amount D 1 can also be obtained by an electronic calculator.
[0027] In the ion doping apparatus used to obtain Formula 1, a dose amount of total ions is adjusted to be the value of D 1 . Then, doping is performed to a semiconductor film or a semiconductor substrate, and a field effect transistor is manufactured using the semiconductor film or the semiconductor substrate. In the above-described doping, the conditions except the dose amount is set to the same as the conditions at the time of doping to the processing object analyzed by an analysis method such as SIMS analysis.
[0028] Further, comparing the condition of heavy doping with the condition of channel doping, a concentration of a compound of a donor impurity or an acceptor impurity included in a source gas, for example, B 2 H 6 in the case of channel doping is lower than that of the case of heavy doping. Further, the dose amount of total ions in the case of channel doping is reduced. Therefore, it is important to change the conditions such as the concentration of the above compound of an impurity in a source gas to be introduced, the dose amount of total ions, or the like and stabilize the conditions after the change, when the same ion doping apparatus is used, the source gas is introduced into an ion source in an apparatus in the condition of heavy doping to generate plasma, and doping is subsequently performed in the condition of channel doping.
[0029] However, there is a problem in that the concentration of a compound of a donor impurity or an acceptor impurity in a source gas takes more time to be stabilized in comparison with the dose amount of total ions. In order to solve the problem, the following treatment process can be used.
[0030] Before doping in the condition of channel doping, supply of a source gas is stopped. Then, the gas which is introduced into an ion source in a ion doping apparatus is switched to a diluent gas, which is included in the source gas. For example, in the case of using a source gas in which B 2 H 6 is diluted with hydrogen, it is switched to hydrogen (preferably, the concentration of H 2 is 100%). In a case of using a source gas in which B 2 H 6 is diluted with argon, it is switched to argon (preferably, the concentration of Ar is 100%). Subsequently, plasma is generated in the ion source, and a first plasma treatment, in which a dummy substrate is irradiated with a generated ion beam, is performed for a predetermined period. A substrate used as the dummy substrate is a glass substrate, a silicon substrate, or the like, and it is placed on a stage in a treatment chamber (chamber) connected to a vacuum pumping system.
[0031] Subsequently, the supply of the diluent gas is stopped, and the treatment chamber is exhausted by using the vacuum pumping system. Then, a source gas, in which the compound of a donor impurity or an acceptor impurity is diluted to a lower concentration than the condition of heavy doping, is supplied to the ion source. In the condition of channel doping using this source gas, a second plasma treatment, in which the dummy substrate is irradiated with an ion beam, is performed for a predetermined period.
[0032] In a case where the first plasma treatment is not performed, the second plasma treatment is needed to be performed for approximately two hours in order to stabilize the concentration of the compound of the impurity included in the source gas. By performing the first plasma treatment, the total time required to perform the first and the second plasma treatments can be decreased to less than two hours.
[0033] After finishing the second plasma treatment, the dummy substrate on the stage is changed to a processing object to be analyzed by an analysis method such as SIMS, and the processing object is doped by the same condition of the second plasma treatment.
[0034] Comparing with a case of performing only the second plasma treatment without the first plasma treatment, the case of performing the first plasma treatment can reduce the variation of the concentration of a donor impurity or an acceptor impurity in the processing object which has been subjected to the doping process; accordingly, the variation of sheet resistance in the object can be reduced.
[0035] In accordance with the invention disclosed in this specification, the following effects can be obtained.
1) In manufacturing a field effect transistor, the aimed threshold voltage can be obtained even when an ion doping apparatus is used. 2) The variation of the threshold voltage of the manufactured field effect transistor can be reduced. 3) The variation of the peak concentration of a donor impurity or an acceptor impurity in a processing object, which has been subjected to a doping process, can be reduced by using an ion doping apparatus. 4) Even when doping is performed at a low concentration as in the case of channel doping, since an ion implantation apparatus is not needed, the manufacturing cost of a field effect transistor can be reduced. 5) When the concentration of the compound of the donor impurity or the acceptor impurity included in the source gas which is introduced to an ion doping apparatus is changed from the first concentration to the second concentration which is lower than the first concentration, the second concentration after the change can easily become stable.
BRIEF DESCRIPTION OF DRAWINGS
[0041] In the accompanying drawings:
[0042] FIG. 1 is a schematic view of an ion doping apparatus;
[0043] FIG. 2 shows a measurement result using a mass spectrometer;
[0044] FIG. 3 shows a measurement result obtained by a mass spectrometer as a comparative example;
[0045] FIG. 4 shows a measurement result obtained by a mass spectrometer;
[0046] FIG. 5 shows a measurement result obtained by a mass spectrometer;
[0047] FIG. 6 shows the concentration distribution of boron in a depth direction analyzed by SIMS;
[0048] FIG. 7 shows a relation between the proportion of B 2 H y + ions in total ions in the condition of heavy doping and the peak concentration of boron in the condition of channel doping;
[0049] FIG. 8 shows a relation between the threshold voltage of an n-channel thin film transistor and the peak concentration of boron in an active layer;
[0050] FIG. 9 shows a relation between the threshold voltage of an n-channel thin film transistor and the square root of the peak concentration of boron in an active layer; and FIGS. 10A to 10 D show manufacturing steps of a thin film transistor.
DETAILED DESCRIPTION OF THE INVENTION
Embodiment Modes
[0000] (Embodiment Mode 1)
[0051] An example of an ion doping apparatus used in the invention disclosed in this specification will be described with reference to FIG. 1 .
[0052] FIG. 1 is a schematic view of an ion doping apparatus. A gas introduction port 101 is connected to a gas supply system 102 which can supply a source gas, in which B 2 H 6 is diluted with hydrogen or a rare gas (such as helium or argon), hydrogen, or a rare gas. The source gas, hydrogen, or the rare gas is introduced to a plasma generating portion 104 in an ion source 103 from the gas supply system 102 to generate plasma in the plasma generating portion 104 . The ion source 103 further includes a discharge generating means 106 and an electrode portion 107 . The electrode portion 107 includes an extraction electrode, an accelerating electrode, a decelerating electrode, and an earth electrode. The electrode portion 107 is also referred to as an extraction electrode system, and the above four electrodes are each provided with a plurality of holes so that an ion beam 108 can pass therethrough. In FIG. 1 , V EXT denotes extraction voltage, V ACC denotes acceleration voltage, and V DEC denotes deceleration voltage.
[0053] The discharge generating means 106 in FIG. 1 is a filament made of a high-melting point material typified by tungsten, which can withstand high temperature of 2000° C. or more, and is provided to be exposed in the plasma generating portion 104 . The number of filaments is not limited to one as shown in FIG. 1 , and a plurality of filaments can be used. The voltage is applied to the filament from a direct-current power source 105 to produce direct-current discharge, and the gas introduced in the plasma generating portion 104 is ionized to generate plasma. Instead of using the above filament, a plate electrode or an antenna having a particular shape, which is connected to a high-frequency (RF) power source, may be used to produce high-frequency discharge, so that plasma is generated.
[0054] The ion beam 108 is extracted from the plasma generated in the plasma generating portion 104 , and is accelerated and irradiated to a substrate 111 on a stage 110 provided in a treatment chamber 109 . The stage 110 can move in a predetermined direction, together with the substrate 111 , and can be applied to a large sized substrate.
[0055] The treatment chamber 109 is provided with a mass spectrometer 113 and a dose amount measuring means 114 at a backside of (below) the stage 110 . Since the stage 110 is movable as described above, the mass spectrometer 113 and the dose amount measuring means 114 can be irradiated with the ion beam 108 without being blocked by the stage 110 . In addition, the treatment chamber 109 is connected to a vacuum pumping system 112 which uses a known vacuum pump such as a turbo-molecular pump. A load lock chamber may be connected to the treatment chamber 109 directly or indirectly, and a means capable of automatically transporting the substrate 111 may be provided between the load lock chamber and the treatment chamber 109 .
[0056] Next, by using the ion doping apparatus shown in FIG. 1 , a specific example of a process to obtain the aforementioned Formula 1, Formula 1′, and Formula 2 is described below.
[0057] As the source gas introduced to the plasma generating portion 104 , B 2 H 6 diluted with hydrogen to a concentration of 5% is used, and a dose amount of total ions is set at 2.0×10 16 cm −2 and an acceleration voltage is set at 80 kV. These values are the conditions of heavy doping. With these conditions, a proportion X of ions of a compound including boron in total ions is calculated from a measurement result obtained by the mass spectrometer 113 .
[0058] FIG. 2 shows a measurement result by the mass spectrometer 113 , i.e. mass spectrum. The horizontal axis shows the mass of ions, and the vertical axis shows the intensity. Peaks of H + ions, H 2 + ions, H 3 + ions, and B 2 H y + ions (y is a positive integer) in the order of increasing the mass are each measured. Besides these peaks, a peak due to BH x + ions (x is a positive integer) is observed in some cases. However, since the amount of the BH x + ions is much smaller than that of the B 2 H y + ions, the peak due to the BH x + ions has much lower intensity than that due to the B 2 H y + ions and is not quantified. From the result shown in FIG. 2 , a proportion X of the B 2 H y + ions is calculated to be 0.174.
[0059] FIG. 3 is a graph shown as a comparative example, which shows a measurement result by the mass spectrometer 113 (mass spectrum). As a source gas, B 2 H 6 diluted with hydrogen to a concentration of 1% is used. A dose amount of total ions is set at 1.3×10 14 cm −2 , and an acceleration voltage is set at 25 kV. These values are the conditions of channel doping. With these conditions, as apparently shown in FIG. 3 , only the peak due to H 2 + ions and the peak due to H 3 + ions are measured. The peak due to the B 2 H y + ions as outstandingly shown in FIG. 2 cannot be distinguished virtually. Therefore, a proportion X of B 2 H y + ions cannot accurately obtained from the result shown in FIG. 3 .
[0060] Since the amount of B 2 H y + ions in total ions depends on the concentration of B 2 H 6 in a source gas, it is impossible to obtain the proportion X of the B 2 H y + ions with high accuracy in the case where a concentration of B 2 H 6 is 1%. When the concentration is 5% or more, the proportion X can sufficiently obtained. Note that a material containing B 2 H 6 at a concentration of 40% or more is not usually used as a source gas since B 2 H 6 is a dangerous gas.
[0061] FIG. 4 and FIG. 5 are graphs showing results (mass spectrum) measured under the same condition as that of FIG. 2 . From the result shown in FIG. 4 , a proportion X of B 2 H y + ions is calculated to be 0.292, and from the result shown in FIG. 5 , a proportion X of B 2 H y + ions is calculated to be 0.374. Further, when various proportions X of B 2 H y + ions is calculated by performing the measurement by the mass spectrometer a plurality of times, the result that the X value varies in the range of 0.1 to 0.4 is obtained.
[0062] FIG. 2 , FIG. 4 , and FIG. 5 are the results measured on different days, waiting one or more week between each measurement. On the other hand, when a plurality of measurements is performed on the same day by the mass spectrometer 113 , the proportion X of B 2 H y + ions is not varied. The result shows that plasma state generated in the plasma generating portion 104 in the ion doping apparatus does not change in one day; however, the plasma state changes when one or more week has passed.
[0063] Next, the source gas is changed to a material in which B 2 H 6 is diluted with hydrogen to a concentration of 1%, the dose amount of total ions is changed to 1.3×10 14 cm −2 , and the acceleration voltage is changed to 25 kV A glass substrate over which a semiconductor film containing silicon as its main component is formed is placed as the substrate 111 on the stage 110 , and doping is performed to the semiconductor film. In this doping step, a plasma state in which a proportion X of B 2 H y + ions is made is maintained. After the doping, a peak concentration Y (cm −3 ) of boron in the semiconductor film is analyzed by SIMS in this embodiment mode.
[0064] FIG. 6 shows the concentration distribution of boron in a depth direction analyzed by SIMS. The horizontal axis shows the depth (nm), and the vertical axis shows the concentration of boron (cm− 3 ). In FIG. 6 , due to a measurement problem, an actual concentration distribution of boron is not reflected in a region to around a depth of 20 nm from a surface. Accordingly, a maximum value of the concentration of boron in a region under a depth of 20 nm is referred to as a peak concentration Y.
[0065] In FIG. 7 , the horizontal axis shows the proportion X of B 2 H y + ions in total ions, the vertical axis shows the peak concentration Y of boron, and a result obtained by plotting values of Y corresponding to values of X is shown. In addition, when a relation of X and Y is shown with collinear approximation, a relational expression, Y=3.1×10 18 X−2.5×10 17 , can be obtained. This expression corresponds to Formula 1. Further, from Formula 1, a relational expression, Y=(D 1 /(1.3×10 14 ))(3.1×10 18 X−2.5×10 17 ), can be obtained, and this corresponds to Formula 1′. D 1 denotes an arbitrary dose amount of total ions.
[0066] Next, channel doping is performed in the same conditions of the concentration of B 2 H 6 in a source gas, the dose amount of total ions, and the acceleration voltage as those after the above change. A semiconductor film containing silicon as its main component, which is channel-doped, is used as an active layer (channel formation region). A channel length L, a channel width W, and an LDD length are set to predetermined sizes, and an n-channel thin film transistor in which a gate insulating film is set to have a predetermined thickness is manufactured. Then, a threshold voltage V th (V) thereof is measured. An LDD length is a length in the same direction as a channel length in an LDD region. Note that the LDD region is not necessarily provided. In this embodiment mode, the channel length is 1 μm, the channel length is 20 μm, the LDD length is 0.2 μm, and the thickness of the gate insulating film is 40 nm. As the gate insulating film, an SiO x N y film (x>y>0) is used. Alternatively, a silicon oxide film may be used as the gate insulating film.
[0067] In FIG. 8 , the vertical axis shows the threshold voltage V th of the n-channel thin film transistor, and the horizontal axis shows the peak concentration Y of boron in the semiconductor film containing silicon as its main component, which is the active layer in the n-channel thin film transistor, and a result obtained by plotting values of V th corresponding to values of Y is shown. From the result, when a relation of V th and Y is shown with collinear approximation, a relational expression, V th =2.1×10 −18 Y−0.11, can be obtained. This corresponds to Formula 2.
[0068] In FIG. 9 , the vertical axis shows the threshold voltage V th of the n-channel thin film transistor, the horizontal axis shows the square root of the peak concentration Y of boron in the semiconductor film containing silicon as its main component which is the active layer of the n-channel thin film transistor, and a result obtained by plotting values of V th correspondingly to values of the square root of Y is shown. From this result, when a relation between V th and the square root of Y is shown with collinear approximation, a relational expression, V th =3.7×10 −9 Y 1/2 −1.7, can be obtained. This also corresponds to Formula 2. Accordingly, it is found that there is not much difference between a correlation coefficient of the relational expression shown in FIG. 9 and that of the relational expression shown in FIG. 8 .
[0069] In addition, in a MOS structure in which metal, an oxide material, and a semiconductor is laminated, it is known that, in a case where the semiconductor is a p-type, a threshold voltage, in which conductivity of a surface of the semiconductor is reversed, is proportional to the square root of the concentration of an acceptor impurity (cm −3 ) in the semiconductor. In a case where the semiconductor is an n-type, a threshold voltage is proportional to the square root of the concentration of a donor impurity (cm −3 ) in the semiconductor. In consideration of this, it is preferable to select the relational expression obtained from FIG. 9 as Formula 2. However, when comparing the relational expression obtained by FIG. 8 with the relational expression obtained by FIG. 9 , there is not much difference between them in a range where the peak concentration Y of boron is high, for example, Y of 5×10 17 cm −3 or more.
[0070] Accordingly, relational expressions corresponding to Formula 1, Formula 1′, and Formula 2 can each be obtained.
[0000] (Embodiment Mode 2)
[0071] When an n-channel thin film transistor is manufactured using an ion doping apparatus in a step of channel doping, steps to obtain a dose amount of total ions in channel doping, required to approximate a threshold voltage V th of the n-channel thin film transistor to a predetermined value (in this embodiment mode, +1.0 V), are carried out. The process is described below.
[0072] According to Formula 2 obtained in Embodiment Mode 1 of this specification, a peak concentration Y of boron in a semiconductor film (used as an active layer) containing silicon as its main component, required to obtain a threshold voltage of +1.0 V is 5.3×10 17 cm −3 .
[0073] In the case where a proportion X of B 2 H y + ions is 0.30, X of 0.30 and Y of 5.3×10 17 cm −3 are assigned to Formula 1′ obtained in Embodiment Mode 1; accordingly, D 1 =1.0×10 14 cm −2 can be obtained. From this result, it is found that a dose amount D 1 of total ions in channel doping, required to obtain a threshold voltage V th , +1.0 V, of the n-channel thin film transistor is 1.0×10 14 cm −2 . Note that a source gas used in the channel doping step is B 2 H 6 diluted with hydrogen to a concentration of 1%, which is used to obtain Formula 1, Formula 1′, and Formula 2 in Embodiment Mode 1.
[0074] Though the calculation in the case where X is 0.30 as an example, is performed, the dose amount D 1 of total ions required to obtain a predetermined threshold voltage varies depending on a proportion X of B 2 H y + ions. Therefore, by adjusting the dose amount of total ions as the proportion X of B 2 H y + ions changes, the threshold voltage can be approximate to an aimed value.
[0075] Further, when Formula 1′ is assigned to Formula 2, a relational expression, V th =2.1×10 −18 (D 1 /(1.3×10 14 ))(3.1×10 18 X−2.5×10 17 )−0.11 or V th =3.7×10 −9 (D 1 /(1.3×10 14 )) 1/2 (3.1×10 18 X−2.5×10 17 ) 1/2 −1.7 can be obtained. Using the relational expression, when values of X and V th are identified, the value of D 1 can be obtained.
[0076] The ion doping apparatus is, in some cases, additionally provided with an electronic calculator capable of controlling the apparatus. A structure may be used, in which Formula 1′, Formula 2, and the above relational expression obtained by assigning Formula 1′ to Formula 2 are stored in this electronic calculator and in which, when inputting an aimed threshold voltage V th , the dose amount D 1 of total ions required to obtain the threshold voltage can be calculated. In addition, a structure may be used, in which the dose amount of total ions can be automatically adjusted to the calculated value by an output signal from the electronic calculator.
[0077] The above electronic calculator is connected to a mass spectrometer, and a proportion X of a predetermined ion species in total ions (in this embodiment mode, B 2 H y + ) can be calculated based on a measurement result by this mass spectrometer. In addition, a calculated result of a necessary dose amount D 1 of total ions is varied depending on the calculated value of X.
[0078] The predetermined threshold voltage is not limited to +1.0 V. In a case of an n-channel thin film transistor, the predetermined threshold voltage is set in the range of +0.3 V to +1.5V, preferably in the range of +0.5 V to +1.0 V; accordingly, electric characteristics are improved, and high yield can be achieved.
[0000] (Embodiment Mode 3)
[0079] After performing channel doping to a semiconductor film containing silicon as its main component by using an ion doping apparatus, steps of obtaining the dose amount of total ions in doping are carried out, which is required to approximate a peak concentration of boron in the semiconductor film obtained by a result of analysis by SIMS to a desired value (in this embodiment mode, 4.4×10 17 cm −3 ). The steps are described below
[0080] When a proportion X of B 2 H y + ions is 0.30, Y of 4 . 4 × 10 17 cm −3 is assigned to Formula 1′ obtained in Embodiment Mode 1; accordingly, D 1 of 8.4×10 13 cm −2 can be obtained. From this result, a dose amount D 1 of total ions required to obtain a peak concentration of boron of 4.4×10 17 cm −3 in a semiconductor film containing silicon as its main component is found to be 8.4×10 13 cm −2 . Note that a source gas used in the channel doping step is B 2 H 6 diluted with hydrogen to a concentration of 1%, which is used to obtain Formula 1 and Formula 1′ in Embodiment Mode 1.
[0081] Though the calculation in the case where X is 0.30 as an example, is performed, the dose amount D 1 of total ions required to obtain a predetermined peak concentration of boron is varied depending on the proportion X of B 2 H y + ions. Therefore, by adjusting the dose amount D 1 of total ions as the proportion X of the B 2 H y + ions changes, the peak concentration of boron in the semiconductor film containing silicon as its main component can be approximated to a desired value.
[0082] A structure may be used, in which the Formula 1′ is stored in an electronic calculator provided in an ion doping apparatus and in which, when inputting a predetermined peak concentration Y of boron, the dose amount D 1 of total ions required to obtain the concentration can be calculated. In addition, a structure in which the dose amount of total ions can be automatically adjusted to the calculated value by an output signal from the electronic calculator may be used.
[0083] In accordance with the process described in this embodiment mode, ten samples are manufactured by performing channel doping while adjusting the dose amount of total ions required to obtain the peak concentration of boron of 4.4×10 17 cm −3 . Then, peak concentrations of boron of the manufactured samples are analyzed by SIMS. In channel doping step, B 2 H 6 diluted with hydrogen to a concentration of 1% is used as a source gas, and an acceleration voltage is set at 25 kV. As the result, three samples have peak concentrations of boron in a range of 3×10 17 cm −3 or more and less than 4×10 17 cm −3 , six samples have peak concentrations of boron in a range of 4×10 17 cm −3 or more and less than ×10 17 cm −3 , and one sample has a peak concentration of boron in a range of 5×10 17 cm −3 or more and less than 6×10 17 cm 3 .
[0084] On the other hand, ten samples are manufactured by a conventional method in which channel doping is performed to a semiconductor film containing silicon as its main component with an ion doping apparatus, and peak concentrations of boron is analyzed by SIMS. In the channel doping, B 2 H 6 diluted with hydrogen to a concentration of 1% is used as a source gas, and an acceleration voltage is set at 25 kV. In addition, a dose amount of total ions is fixed at 1×10 14 cm −2 . As the result, three samples have peak concentrations of boron in the range of 2×10 17 cm −3 or more and less than 3×10 17 cm −3 , three samples have peak concentrations of boron in a range of 3×10 17 cm −3 or more and less than 4×10 17 cm −3 , two samples have peak concentrations of boron in the range of 5×10 17 cm −3 or more and less than 6×10 17 cm −3 , one sample has a peak concentration of boron in a range of 6×10 17 cm −3 or more and less than 7×10 17 cm −3 , and one sample has a peak concentration of boron in a range of 8×10 17 cm −3 or more and less than 9×10 17 cm −3 .
[0085] In comparing the both results with each other, it is clear that the variation of the peak concentration of boron in the case of using the present embodiment mode can be smaller than that of the case where the conventional method is used, and that a value close to the predetermined peak concentration of boron can be obtained according to the present embodiment mode.
[0000] (Embodiment Mode 4)
[0086] A process for changing a source gas to be used having a concentration of B 2 H 6 of 5% to that having a concentration of 1% in Embodiment Mode 1 of this specification is described below.
[0087] Supply of the source gas (B 2 H 6 diluted with hydrogen to a concentration of 5%) into the plasma generating portion 104 of the ion doping apparatus shown in FIG. 1 is stopped, and hydrogen is substituted as a supplied gas. Then, hydrogen plasma is generated, and a dummy treatment in which the dummy substrate placed on the stage 110 in the treatment chamber 109 is irradiated with the ion beam 108 extracted through the electrode portion 107 is performed for one hour. The dummy substrate may be any of a glass substrate or a silicon substrate. At that time, the dose amount is set at 3×10 15 cm −2 , and the acceleration voltage is set at 50 kV.
[0088] Then, supply of hydrogen to the plasma generating portion 104 is stopped, and the treatment chamber 109 is exhausted for one hour by using the vacuum pumping system 112 . Subsequently, the source gas in which B 2 H 6 is diluted with hydrogen to a concentration of 1% is supplied to the plasma generating portion 104 to generate plasma, and a dummy treatment in which the above substrate is irradiated with the ion beam 108 extracted through the electrode portion 107 is performed for 30 minutes. At that time, a dose amount of total ions is set at 1.3×10 14 cm −2 , and an acceleration voltage is set at 25 kV.
[0089] Then, the dummy substrate on the stage 110 is converted to a glass substrate over which a semiconductor film containing silicon as its main component is formed. The semiconductor film is doped, without changing conditions such as the dose amount of total ions and the acceleration voltage.
[0090] In this embodiment mode, a dummy treatment, before the semiconductor film is actually doped, only requires an hour and a half.
[0000] [Embodiment]
[0091] Steps of manufacturing a thin film transistor by using the invention disclosed in this specification will be described below.
[0092] As shown in FIG. 10A , a base layer 902 is formed over a substrate 901 having an insulating surface. A base layer 902 is formed of a plurality of films and can have a structure including two or more of a silicon nitride film containing oxygen, a silicon oxide film containing nitrogen, a silicon oxide film, or a silicon nitride film. Either or both of a film containing high-melting point metal having a melting point of 2000° C. or more (for example, tungsten) as its main component and a film containing a compound of the high-melting point metal as its main component can be further provided between the substrate 901 and the base layer 902 or between two films of the films forming the base layer 902 .
[0093] A semiconductor film containing silicon as it main component, for example, a crystalline or amorphous silicon film, is formed over the base layer 902 , and a pattern 903 having a predetermined shape is formed from this semiconductor film by a photolithography step.
[0094] Channel doping is performed to the pattern 903 with an ion doping apparatus as described in FIG. 1 . In the channel doping, B 2 H 6 diluted with hydrogen to a concentration of 1% is used as a source gas, and an acceleration voltage is 25 kV. The dose amount of total ions is set at the value obtained in accordance with Embodiment Mode 2 or Embodiment Mode 3 in this specification. By using the invention disclosed in this specification, when the dose amount of total ions is set, a predetermined peak concentration of boron or a predetermined threshold voltage can be obtained easily.
[0095] After the channel doping of the semiconductor film is performed before forming the pattern 903 , the pattern 903 may be formed by a photolithography step.
[0096] Subsequently, a gate insulating film 904 is formed to cover the pattern 903 as shown in FIG. 10B . Further, a conductive layer is formed over the gate insulating film 904 . This conductive layer is formed of a plurality of films and can have a structure including a metal film of titanium, niobium, tantalum, tungsten, molybdenum, chromium, aluminum, or copper. In addition to the metal film, a conductive metal nitride film can be used. Then, a gate electrode 905 having a predetermined shape is formed from this conductive layer by using a photolithography step.
[0097] Next, a portion of the pattern 903 shown with diagonal lines is doped with phosphorus using the gate electrode 905 as a mask by using an ion doping apparatus. At this time, PH 3 diluted with hydrogen to a concentration of 5% is used as a source gas, the dose amount of total ions is set at 2.5×10 13 cm −2 , and the acceleration voltage is set at 80 kV. In this doping, the dose amount of total ions can be set by applying the invention disclosed in this specification so that a peak concentration of phosphorus in the pattern 903 can have a predetermined value.
[0098] An insulating layer for forming a sidewall is formed to cover at least a side surface of the gate electrode 905 , over the gate insulating film 904 . This insulating layer can have a structure including either or both of a silicon oxide film and a silicon oxide film containing nitrogen. By performing anisotropic etching to this insulating layer, a sidewall 906 shown in FIG. 10C is selectively formed.
[0099] Doping of phosphorus is again performed by using the gate electrode 905 and the sidewall 906 as masks. At this time, PH 3 diluted with hydrogen to a concentration of 5% is used as a source gas, the dose amount of total ions is set at 3.0×10 15 cm −2 , and the acceleration voltage is set at 20 kV. As the result, since a region overlapping with the sidewall 906 in the pattern 903 is prevented from being doped with phosphorus, source and drain regions 907 and 908 , and LDD regions (low concentration impurity regions) 909 and 910 are formed in the pattern 903 . A portion of the pattern 903 , which is below the gate electrode 905 and between the LDD regions 909 and 910 , is a channel formation region.
[0100] Next, an interlayer insulating layer 911 is formed as shown in FIG. 10D . The interlayer insulating layer 911 is formed of a plurality of films and can have a structure including two or more of a silicon nitride film containing oxygen, a silicon oxide film containing nitrogen, a silicon oxide film, or a silicon nitride film.
[0101] Anisotropic etching is performed to the interlayer insulating layer 911 and the gate insulating film 904 to form contact holes to partially expose the source and drain regions 907 and 908 . Then, wirings 912 and 913 are formed over the interlayer insulating layer 911 . The wirings 912 and 913 can be formed of a plurality of films including a film containing metal as its main component or a conductive film containing a metal compound. The wirings 912 and 913 are each electrically connected to either the source or drain region 907 or 908 through the contact holes.
[0102] In accordance with the above described steps, an n-channel thin film transistor, in which a channel length, a channel width, and an LDD length each have predetermined sizes and a gate insulating film has a predetermined thickness, can be manufactured.
[0103] The present application is based on Japanese Priority Application No. 2005-034719 filed on Feb. 10, 2005 with the Japan Patent Office, the entire contents of which are hereby incorporated by reference.
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A doping method comprising the steps of; obtaining a proportion X of ions of a compound including a donor or an acceptor impurity in total ions from mass spectrum by using a first source gas of a first concentration; analyzing a peak concentration Y of the compound in a first processing object which is doped by using a second source gas of a second concentration equal to or lower than the first concentration, referring to a dose amount of total ions as Do and setting an acceleration voltage at a value, obtaining a dose amount D 1 of total ions from a expression, Y=(D 1 /D 0 )(aX+b), and doping a second processing object with the donor or the acceptor impurity by a ion doping apparatus using a third source gas, wherein a dose amount of total ions is set at D 1 , and an acceleration voltage is set at the value.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Korean Patent Application No. 10-2007-0123375, filed on Nov. 30, 2007, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention generally relates to an organic light emitting display and a driving method thereof.
[0004] 2. Description of Related Art
[0005] Recently, various flat panel display devices having reduced weight and volume in comparison to a cathode ray tube (CRT) have been developed. Examples of flat panel display devices include liquid crystal displays, field emission displays, plasma display panels, organic light emitting displays, etc.
[0006] Among these examples, the organic light emitting display displays an image utilizing organic light emitting diodes (OLEDs) that generate light by the recombination of electrons and holes. An organic light emitting display generally has a rapid response speed and a low power consumption.
[0007] FIG. 1 is a circuit diagram illustrating a pixel of a conventional organic light emitting display.
[0008] Referring to FIG. 1 , a pixel 4 of a conventional organic light emitting display includes an organic light emitting diode OLED and a pixel circuit 2 that is coupled to a data line Dm and a scan line Sn to control the organic light emitting diode OLED.
[0009] An anode electrode of the organic light emitting diode OLED is coupled to the pixel circuit 2 , and a cathode electrode thereof is coupled to a second power ELVSS. The organic light emitting diode OLED generates light having a brightness (which may be predetermined) corresponding to a current supplied from the pixel circuit 2 .
[0010] The pixel circuit 2 controls an amount of current supplied to the organic light emitting diode OLED in accordance with a data signal supplied to the data line Dm when a scan signal is supplied to the scan line Sn. To this end, the pixel circuit 2 includes a second transistor M 2 coupled between a first power ELVDD and the organic light emitting diode OLED, and a first transistor M 1 coupled to the second transistor M 2 , the data line Dm and the scan line Sn, and a storage capacitor Cst coupled between a gate electrode and a first electrode of the second transistor M 2 .
[0011] A gate electrode of the first transistor M 1 is coupled to the scan line Sn, and a first electrode thereof is coupled to the data line Dm. And, a second electrode of the first transistor M 1 is coupled to one terminal of the storage capacitor Cst. Herein, the first electrode is set as one of a source electrode or a drain electrode, and the second electrode is set as an electrode different from the first electrode. For example, if the first electrode is a source electrode, the second electrode is a drain electrode, and vice versa. The first transistor M 1 coupled to the scan line Sn and the data line Dm supplies a data signal on the data line Dm to the storage capacitor Cst by being turned on when the scan signal is supplied from the scan line Sn. At this time, the storage capacitor Cst is charged with a voltage corresponding to the data signal.
[0012] A gate electrode of the second transistor M 2 is coupled to one terminal of the storage capacitor Cst, and a first electrode thereof is coupled to the other terminal of the storage capacitor Cst and the first power ELVDD. And, a second electrode of the second transistor M 2 is coupled to an anode electrode of the organic light emitting diode OLED. The second transistor M 2 controls an amount of current flowing from the first power ELVDD, through the organic light emitting diode OLED, to the second power ELVSS in accordance with a voltage stored in the storage capacitor Cst. At this time, the organic light emitting diode OLED generates light corresponding to the amount of current supplied by the second transistor M 2 .
[0013] In the conventional pixel 4 , the second transistor M 2 is driven as a substantially constant current source supplying a current (e.g., a predetermined current) to the organic light emitting diode OLED in accordance with the voltage stored in the storage capacitor Cst. Herein, the transistor M 2 should be driven in its saturation region in order that the second transistor M 2 drives a substantially constant current. Therefore, the voltage of the first power ELVDD and the second power ELVSS are set so that the second transistor M 2 is driven in the saturation region.
[0014] In more detail, the voltage between the first power ELVDD and the second power ELVSS can be expressed as shown in the following Equation 1:
[0000] ELVDD−ELVSS>Vds — sat+Voled+Vmt+Vmo Equation 1
[0015] In Equation 1, Vds_sat represents a minimum voltage between the first electrode and the second electrode (e.g., the source and the drain) of the second transistor M 2 for driving the second transistor M 2 in the saturation region when a maximum current (i.e., the saturation current of the second transistor M 2 when the data value representing the highest gray level is supplied on the data line Dm and stored in the storage capacitor Cst) flows from the pixel circuit 2 to the organic light emitting diode OLED. Voled represents a voltage applied to the organic light emitting diode OLED when the maximum current is supplied.
[0016] Vmt represents voltage margin due to a process deviation of the second transistor M 2 , and Vmo represents a voltage margin corresponding to the process deviation and the temperature characteristics of the organic light emitting diode OLED.
[0017] Actually, in the organic light emitting diode OLED, the voltage margin Vmo corresponding to the temperature changes even in the case where the same current is supplied. Therefore, Vmo is set such that the pixel 4 can be stably driven in consideration of the temperature characteristics of the organic light emitting diode OLED.
[0018] Meanwhile, when the voltages of the first power ELVDD and the second power ELVSS are set as shown in Equation 1, power consumption may be undesirably high. In particular, the voltage margin Vmo that is added in consideration of the temperature characteristics may result in 20% to 30% of the power consumption. Therefore, a method capable of reducing power consumption by lowering the margin voltage of Vmo is desired.
SUMMARY
[0019] To address these and other issues, an organic light emitting display and a driving method thereof having features of an exemplary embodiment of the present invention is capable of reducing power consumption by lowering the voltage margin corresponding to process deviations and the temperature characteristics of the organic light emitting diode OLED.
[0020] According to an exemplary embodiment of the present invention, an organic light emitting display includes first and second power generators for generating first and second powers, respectively. A plurality of pixels within the display each include an organic light emitting diode (OLED). At least some pixels among the plurality of pixels are in a display region of the organic light emitting display, and the at least some pixels each include a driving transistor for controlling a first current through the OLED. A voltage controller supplies a second current to the OLED of at least one specific pixel of the plurality of pixels, and controls a voltage of the second power supply in correspondence to a first voltage of the OLED provided when the second current is supplied to the OLED.
[0021] In a further exemplary embodiment, the voltage controller includes a controller for controlling a turn-on and a turn-off of the first transistor, the controller comprising a memory for storing first data representing a saturation voltage for driving the driving transistor in a saturation region, and a margin voltage corresponding to a range of process deviation of the driving transistor when the driving transistor supplies a maximum current; and a register for generating second data, wherein the register is configured to adjust a value of the second data in accordance with a comparator output; a first digital-analog converter for converting the first data into a second voltage; a current source for supplying the second current to the OLED when the first transistor is turned on; an adder for adding the first voltage and the second voltage to generate a third voltage; a comparator for comparing the third voltage with a voltage of the first power, and for supplying the comparator output; and a second digital-analog converter for converting the second data to an analog voltage.
[0022] According to another exemplary embodiment of the present invention, a method is provided for driving an organic light emitting display including a first power, a second power, an organic light emitting diode, and a pixel circuit comprising a driving transistor for controlling a current through the organic light emitting diode. In this embodiment, the method includes storing first data representing a saturation voltage for driving the driving transistor in a saturation region, and a margin voltage corresponding to a range of process deviation of the driving transistor when the driving transistor supplies a current corresponding to a highest gray level; supplying a first current to an OLED of at least one specific pixel; comparing a third voltage with a voltage of the first power, the third voltage comprising a sum of a first voltage extracted from the OLED while supplying the first current and a second voltage generated by converting the first data to an analog signal; and controlling a voltage of the second power in accordance with a result of comparing the third voltage with the voltage of the first power.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The accompanying drawings, together with the specification illustrate exemplary embodiments of the present invention, and, together with the description, serve to explain the principles of the present invention.
[0024] FIG. 1 is a circuit diagram illustrating a conventional pixel in the related art;
[0025] FIG. 2 is a block diagram illustrating an organic light emitting display according to a first exemplary embodiment of the present invention;
[0026] FIG. 3 is a block diagram illustrating an organic light emitting display according to a second exemplary embodiment of the present invention; and
[0027] FIG. 4 is simplified schematic diagram illustrating the voltage controller and the pixel of FIGS. 2 and 3 .
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0028] Hereinafter, certain exemplary embodiments of the present invention will be described with reference to the accompanying drawings. Herein, when a first element is described as being coupled to a second element, the first element may be directed coupled to the second element, or it may be indirectly coupled to the second element via a third element. Further, some of the elements that may not be essential for a complete understanding of the invention have been omitted for clarity. Like reference numerals refer to like elements throughout.
[0029] Hereinafter, certain exemplary embodiments of the present invention, which can be easily carried out by those skilled in the art, will be described with reference to the accompanying FIGS. 2 through 4 .
[0030] FIG. 2 is a block diagram illustrating an organic light emitting display according to an exemplary embodiment of the present invention.
[0031] Referring to FIG. 2 , the organic light emitting display according to the exemplary embodiment of the present invention displays images during a plurality of frames, and includes a display region (or display unit) 30 that includes a plurality of pixels 40 and 42 coupled to scan lines S 1 -Sn and data lines D 1 -Dm, a scan driver 10 that drives the scan lines S 1 -Sn, a data driver 20 that drives the data lines D 1 -Dm, and a timing controller 50 that controls the scan driver 10 and the data driver 20 .
[0032] The organic light emitting display according to the exemplary embodiment of the present invention further includes a first power generator 60 that generates first power ELVDD, a voltage controller 80 that controls a second power generator 70 corresponding to a voltage extracted from a pixel (e.g., a specific pixel) 42 , and a second power generator 70 that generates a second power ELVSS under the control of the voltage controller 80 .
[0033] In the display region 30 , the first power ELVDD from the first power generator 60 and the second power ELVSS from the second power generator 70 are coupled to the pixels 40 and 42 . When the scan driver 10 supplies the scan signal, the respective pixels 40 and 42 coupled to the first power ELVDD and the second power ELVSS are selected, and emit light at a brightness corresponding to the data signal supplied by the data driver 20 .
[0034] To this end, the respective pixels 40 and 42 include an organic light emitting diode (not illustrated in FIG. 2 ) and a pixel circuit (not illustrated in FIG. 2 ) that supplies current to the organic light emitting diode. The pixel circuit, which typically includes at least one transistor and capacitor, controls an amount of current supplied from the first power ELVDD to the second power ELVSS via the organic light emitting diode, in accordance with the data signal. The organic light emitting diode emits red, green, or blue light in accordance with the amount of current supplied from the pixel circuit.
[0035] The scan driver 10 sequentially supplies the scan signals to the scan lines S 1 -Sn. If the scan signals are sequentially supplied to the scan lines S 1 -Sn, rows of pixels 40 and 42 are sequentially selected.
[0036] The data driver 20 generates data signals using data supplied from the timing controller 50 , and supplies the generated data signals to the data lines D 1 -Dm whenever the scan signals are supplied. Then, the data signals are supplied to the pixels 40 and 42 selected by the scan signals.
[0037] The timing controller 50 generates a data driving control signal DCS and a scan driving control signal SCS that correspond to synchronization signals supplied from the outside. The data driving control signal DCS generated from the timing controller 50 is supplied to the data driver 20 , and the scan driving control signal SCS generated therefrom is supplied to the scan driver 10 . And, the timing controller 50 rearranges data supplied from the outside to supply it to the data driver 20 .
[0038] The voltage controller 80 is coupled to at least one specific pixel 42 included in the display region 30 . The voltage controller 80 extracts a voltage applied to the organic light emitting diode of the specific pixel 42 , while supplying a reference current (e.g., a predetermined current) to the specific pixel 42 . At this time, the voltage extracted from the organic light emitting diode includes voltage information applied to the organic light emitting diode corresponding to the temperature currently driven (i.e., Vmo+Voled). The voltage controller 80 extracting a voltage of the pixel 42 controls the second power generator 70 to minimize or reduce power consumption.
[0039] The second power generator 70 generates second power ELVSS corresponding to the signal from the voltage controller 80 (described below) and supplies the generated second power ELVSS to the pixels 40 and 42 .
[0040] The first power generator 60 generates first power ELVDD and supplies the generated first power ELVDD to the pixels 40 and 42 .
[0041] In FIG. 2 , the voltage controller 80 is illustrated as being coupled to the specific pixel 42 included in the display region 30 , but the present invention is not limited thereto. In practice, as shown in FIG. 3 , the voltage controller 80 may be coupled to at least one dummy pixel 44 positioned in a region (i.e., a non-display region) other than the display region 30 .
[0042] FIG. 4 is simplified schematic diagram illustrating the voltage controller 80 and the pixel 42 , 44 of FIGS. 2 and 3 .
[0043] Referring to FIG. 4 , the pixel 42 , 44 includes a pixel circuit 48 that supplies current to an organic light emitting diode OLED, whereby the organic light emitting diode OLED emits light corresponding to the current supplied from the pixel circuit 48 , and a first transistor M 3 coupled between an anode electrode of the organic light emitting diode OLED and a voltage controller 80 .
[0044] Herein, when the pixel as shown in FIG. 4 is the dummy pixel 44 , the first transistor M 3 is turned on every i th (i is a natural number) frame period. When the first transistor M 3 is turned on, the voltage controller 80 supplies a current, e.g., a maximum current corresponding to the brightest gray level, to the organic light emitting diode OLED. At this time, the pixel circuit 48 blocks an electrical coupling between a first power ELVDD and the organic light emitting diode OLED. Actually, when a pixel as shown in FIG. 4 is the dummy pixel 44 , the pixel circuit 48 and the first power ELVDD may be omitted.
[0045] Whenever the first transistor M 3 is turned on, the voltage controller 80 controls a voltage of a second power ELVSS in accordance with a voltage applied to the organic light emitting diode OLED. Herein, if a period in between times that the first transistor M 3 is turned on is a short period (for example, i=2), the voltage of the second power ELVSS is frequently changed, resulting in frequent changes in the brightness of a panel, which may negatively affect a user's viewing experience. Therefore, i is experimentally determined in consideration of the size and resolution of the panel such that the changes in the brightness of the panel are not necessarily observed by a viewer.
[0046] Meanwhile, when the pixel as shown in FIG. 4 is the specific pixel 42 within the display region 30 , the first transistor M 3 is turned on when the specific pixel does not perform a display operation. For example, the first transistor M 3 included in the specific pixel 42 is turned on during a period when the specific pixel displays black. In this case, the voltage controller 80 is supplied with data from a timing controller 50 to the specific pixel 42 , and turns on the first transistor M 3 when the data displays black (e.g., in the case of having “00000000” bits). As described above, the first transistor M 3 is turned on during the period that the specific pixel 42 displays black, thereby not causing a collision between the current (e.g., the predetermined current) supplied from the voltage controller 80 and the current supplied form the pixel circuit 48 .
[0047] Meanwhile, in the exemplary embodiment described, the voltage controller 80 does not unconditionally turn on the first transistor M 3 when the specific pixel 42 displays black. In other words, the voltage controller 80 controls a point of time when the first transistor M 3 is turned on such that the change in voltage of the second power ELVSS is not observed by a viewer.
[0048] The voltage controller 80 includes a current source 81 , an adder 82 , a comparator 83 , a first digital-analog converter 84 (hereinafter, referred to as “first DAC”), a second DAC 85 , and a controller 86 .
[0049] The current source 81 supplies a current (e.g., a predetermined current) to the organic light emitting diode (OLED) corresponding to a current when the pixels 40 emit light at the highest brightness.
[0050] The adder 82 adds a first voltage Vsamp applied to the organic light emitting diode OLED with a second voltage Vtft supplied from the first DAC 84 when the current source 81 supplies the current to the organic light emitting diode OLED, and supplies the sum as a third voltage to the comparator 83 .
[0051] The comparator 83 compares the third voltage with the voltage of the first power ELVDD, and provides the comparative result to the controller 86 .
[0052] The controller 86 controls turn-on and turn-off of the first transistor M 3 . The controller 86 includes a memory 87 and a register 88 .
[0053] A first data corresponding to a total voltage of VDS_sat and Vmt is stored in the memory. In this exemplary embodiment, VDS_sat and Vmt are set as fixed values in every panel so that they can be previously stored in the memory 87 .
[0054] The first DAC 84 converts the first data supplied from the memory 87 to the second voltage (Vtft=VDS_sat+Vmt) to supply it to the adder 82 .
[0055] The register 88 supplies a second data of j (j is a natural number) bits, the value of which increases or decreases in accordance with the comparative result of the comparator 83 , to the second DAC 85 .
[0056] The second DAC 85 converts the second data supplied from the register 88 to analog voltage FBV to supply it to a second power generator 70 .
[0057] The second power generator 70 generates the second power ELVSS using the analog voltage FBV supplied from the second DAC 85 . Herein, the second power ELVSS is generated as shown in the following equation 2:
[0000] ELVSS=α×FBV+ΔV Equation 2
[0058] In Equation 2, α represents a real number larger than 0 and ΔV represents a voltage, and is also a real number. In Equation 2, α and ΔV are previously and experimentally determined in order that the second power ELVSS can be stably generated from the analog voltage FBV. Herein, α and ΔV are set as fixed values so that the voltage of the second power ELVSS is determined by the analog voltage FBV.
[0059] Explaining an exemplary operation process in detail, first the first data stored in the memory 87 is supplied to the first DAC 84 . The first DAC 84 converts the first data supplied form the memory 87 to the second voltage Vtft to supply it to the adder 82 .
[0060] The first transistor M 3 is turned on by controlling the controller 86 . At this time, current is not supplied from the pixel circuit 48 to the organic light emitting diode OLED. If the first transistor M 3 is turned on, a current (e.g., a predetermined current) from the current source 81 is supplied to the organic light emitting diode OLED. At this time, the first voltage Vsamp is applied to the organic light emitting diode OLED. Herein, the value of the first voltage Vsamp varies depending on the temperature currently experienced. For example, the first voltage Vsamp may be about 4V at a high temperature (e.g., 80° C.) and may be about 8V at a low temperature (e.g., −30° C.).
[0061] The first voltage Vsamp applied to the organic light emitting diode OLED is supplied to the adder 82 . At this time, the adder 82 generates the third voltage by adding the first voltage Vsamp and the second voltage Vtft, and supplies the generated third voltage to the comparator 83 .
[0062] The comparator 83 supplied with the third voltage compares the third voltage with the voltage value of the first power ELVDD and supplies the comparative result to the register 88 . For example, when the first power ELVDD has a high voltage, the comparator 83 supplies a first control signal to the register 88 , and when the third voltage has a high voltage, the comparator 83 supplies a second control signal to the register 88 .
[0063] The register 88 increases or decreases the value of the second data in accordance with the control signal supplied from the comparator 83 . For example, when the first control signal is input, the comparator 83 increases the value of the second data, and when the second control signal is input, the comparator 83 decreases the value of the second data. In other words, the comparator 83 increases or decreases the value of the second data in order that the third voltage output from the adder 82 has a similar value with the first power ELVDD.
[0064] The second DAC 85 converts the second data into the analog voltage FBV to supply it to the second power generator 70 .
[0065] The second power generator 70 generates the second power ELVSS by using the analog voltage FBV supplied from the second DAC 85 . Thereafter, the voltage controller 80 generates an optimal voltage of the second power ELVSS corresponding to the temperature currently driven, repeating the processes as described above.
[0066] In summary, the organic light emitting display according to the exemplary embodiment of the present invention extracts the voltage applied to the organic light emitting diode OLED corresponding to the temperature, and controls the voltage of the second power ELVSS corresponding to the extracted voltage. As described above, the voltage of the second power ELVSS is controlled using the voltage extracted from the organic light emitting diode OLED, making it possible to reduce or minimize power consumption. In other words, the voltage of Vmo as shown in Equation 1 is controlled to correspond to the temperature currently driven so that there is no need for an unnecessarily wide margin.
[0067] Meanwhile, in another exemplary embodiment of the present invention the voltage controller 80 can be coupled to at least two specific pixels 42 or dummy pixels 44 . In this case, the voltage controller 80 repeats the processes as described above in the specific pixel 42 or the dummy pixel 44 . And, the register 88 controls the voltage of the second power generator 70 only when the same result is obtained in both or all the specific pixels 42 or the dummy pixels 44 , that is, only when the same control signal (the first control signal or the second control signal) is generated in all the specific pixels 42 or the dummy pixels 44 .
[0068] The organic light emitting display and the driving method thereof according to various exemplary embodiments of the present invention sets the voltage value of the second power ELVSS to correspond to the temperature currently driven, making it possible to reduce power consumption.
[0069] While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, and equivalents thereof.
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An organic light emitting display and a driving method thereof capable of reducing power consumption. A driving transistor controls a current through an organic light emitting diode of the display. A voltage controller supplies a first voltage to the anode of the OLED of at least one specific pixel and controls the cathode voltage of the OLED in correspondence to a second current through the OLED, such that the cathode voltage corresponds to the first voltage supplied to the OLED. Thus, the driving transistor can be driven in saturation mode with consistent current in spite of process variations, with a reduced power consumption.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an adaptive echo canceller technique used in communications equipment. More particularly, the invention relates to a testing method and device which are preferable to make sure of a function of an echo canceller.
2. Description of the Related Art
FIG. 10 shows arrangement of a testing system used for making sure of a function of an echo canceller contained in the conventional communications equipment. As shown, 11 is an echo canceller, 101 is a white noise generator, 102 is a level detector, 103 is a delay circuit, and 104 is an attenuator. The arrangement is defined according to the echo canceller and its relevant testing method discussed in CCITT Recommendation G. 165, (red book) pp 258-279. FIG. 2 is a block diagram showing basic arrangement of the echo canceller shown in FIG. 10. As shown in FIG. 2, 21 is a tap coefficient updating unit, 22 is a tap coefficient memory, 23 is an echo estimator, 24 is a far-end talker signal memory, 25 is a double talk detector, 26 is a subtracter, and 27 is a center clipper.
In order to make sure of a function of the normal echo canceller 11 under the foregoing arrangement, as shown in FIG. 10, the echo canceller 11 is connected at a terminal 3a to the white noise generator 101 in a manner to receive an output signal r(n) from the generator 101 and connected between terminals 3b and 3c to the delay circuit 103 and the attenuator 104 for simulating an echo path in a manner to receive an output signal s(n) from the attenuator 104. Under the connecting arrangement, the echo canceller 11 serves to send an output signal e(n) to the level detector 102 for detecting a residual echo level of an output signal e(n) from the echo canceller 11. The prior art relevant to detection of an echo canceller is discussed in JP-A-63-42528 and Dutteiler et al. "A single-chip VLSI Echo Canceller", the Bell System Technical Journal, Feb, 1980, pp 149-160.
The aforementioned prior art does not offer a simple function-testing method the echo canceller itself can realize. That is, it is necessary to connect the white noise generator 101, the level detector 102, the delay circuit 103, and the attenuator 104 to the echo canceller 11. Besides, the testing method requires disabling a call/talk alive in the echo canceller 11 for doing the test. It results in being unable to do a function test while a talk is alive.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a testable echo canceller which is, by itself, capable of simply making sure of its function.
It is another object of the invention to provide a testable echo canceller and its relevant testing method which are capable of making sure of the function while a call/talk is alive and are preferable to any use of a communications system.
In order to achieve those objects, a testable echo canceller according to the invention comprises, in itself, a test far-end talker signal generating means, an echo signal generating means for simulating an echo path and generating an echo signal, an echo detecting means for detecting a residual echo level, and a control means for switching a signal path to an echo cancel mode or test mode. This arrangement results in allowing the echo canceller to makes sure of the function by itself.
With a means for enabling a call/talk signal to bypass the echo canceller in the course of the test in a communications system, it is possible to test an echo canceller while a call/talk is alive.
The function offered by each of those means can be realized by digital signal processors (DSP) composing the echo canceller and the software run on these processors. It means that simple arrangement makes it possible to realize those means.
For performing a test with the testable echo canceller, the far-end talker signal generating means serves to generate a l-bit white noise as a far-end talker signal and the echo signal generating means serves to generate an echo signal, which is the white noise far-end talker signal delayed and attenuated to the same extent as the simulated echo path. The residual echo detecting means serves to detect a level of a residual echo signal, which means the echo signal left after each cancellation, and the signal path switching means serves to control a signal input or output to the echo canceller and send out a testing result of the echo canceller through the residual echo detecting means.
With the bypassing means, a near-end talker signal input to the echo canceller for testing the function bypasses the echo canceller when it is output. Hence, the test can be performed without having to interrupt a call/talk passing on to the echo canceller.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing one embodiment of a testable echo canceller according to an embodiment of the invention;
FIG. 2 is a block diagram showing a conventional echo canceller to be used for that shown in FIG. 1;
FIG. 3 is a flowchart showing the operation of a control unit shown in FIG. 1;
FIG. 4 is a flowchart showing the operation done in the echo canceller shown in FIGS. 1 and 2;
FIG. 5 is a block diagram showing one example of a far-end talker signal generating unit of the echo canceller shown in FIG. 1;
FIG. 6 is a block diagram showing one example of an echo signal generating unit of the echo canceller shown in FIG. 1;
FIG. 7 is a block diagram showing a testable echo canceller according to another embodiment of the invention;
FIG. 8 is a flowchart showing the operation of the embodiment shown in FIG. 7;
FIG. 9 is a block diagram showing an embodiment of a communications equipment to which the testable echo canceller according to the invention is applied; and
FIG. 10 is a block diagram illustrating a testing method of the conventional echo canceller.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the invention will be described in detail with reference to the appended drawings.
FIG. 1 is a block diagram showing a testable echo canceller according to an embodiment of the invention. As shown, 11 is an echo canceller, 12 is a far-end talker signal generating unit, 13 is an echo signal generating unit, 14 is a residual echo detecting unit, and 15 is a control unit for controlling a signal input or output to the echo canceller in a manner to form an echo canceller mode and a test mode for the far-end talker signal by switching a signal path in the echo canceller.
The basic arrangement of the echo canceller 11 can employ the arrangement shown in the block diagram of FIG. 2.
FIG. 3 is a flowchart showing the operation of the control unit 15 in FIG. 1. As shown, the control unit 15 serves to normally connect a switch SW1 to a terminal 1e side, a switch SW2 to a terminal 1h side, and a switch SW3 to a terminal 1j side if the test is determined to be OFF in the test ON check at a step 301. The echo canceller 11, therefore, receives a far-end talker signal r(n) at a terminal 1a and an echo signal s(n) at a terminal 1c through an echo path connected between terminals 1b and 1c and sends out a residual echo signal e(n) at a terminal 1d. When the echo canceller stays in this normal operating state, the process returns to a step 301 if the test is determined to be OFF in the test ON check.
If the test is determined to be ON in the test ON check at the step 301, the control unit 15 serves to connect the switch SW1 to a terminal if side, the switch SW2 to a terminal 1g side, and the switch SW3 to a terminal 1i side at a step 303. The echo canceller 11, therefore, receives a far-end talker signal r(n) from the far-end talker signal generating unit 12 and an echo signal s(n) from the echo signal generating unit 13. At a next step 304, the process serves to set a ready state for starting the test of the echo canceller 11. In the ready state, if the test is determined to be ON in the test ON check at a step 305, the process serves to output a testing result at a step 306 and then returns to a step 301.
FIG. 4 is a flowchart showing the operation of the echo canceller shown in FIGS. 1 and 2. As shown, if the test is determined to be OFF in the test ON check at a step 401, the control unit 15 serves to normally connect the switches SW1, SW2, and SW3 to the terminals 1e, 1h, and 1j sides, respectively. At a step 402, the echo canceller receives a far-end talker signal r(n) at the terminal 1a (3a) into the far-end talker signal memory 24. The echo canceller 11 receives an echo signal s(n) at the terminal 1c (3c) through an echo path connected between the terminals 1b and 1c (3b and 3c). Based on the normal fundamental operation of the echo canceller 11, if the test is determined to be OFF in the test ON check at a step 405, the center clipper 27 serves to send out an output as a residual echo signal e(n) at the terminal 1d (3d).
Then, a description will be directed to the fundamental operation of the echo canceller 11 shown in FIG. 2. Based on the far-end talker signal r(n) stored in the far-end talker signal memory 24 and a tap coefficient h 1 stored in the tap coefficient memory 22, the echo estimator 23 serves to perform a filtering operation of; ##EQU1## where N denotes a number of filter steps and K denotes a tap number. It results in deriving a pseudo echo signal y(n). Based on the echo signal s(n) and the pseudo echo signal y(n), the subtracter 26 serves to perform an operation of;
e(n)=s(n)-y(n)
It results in producing a residual echo signal e(n).
The center clipper 27 serves to derive a residual echo signal level e pow . Then, the following equation is performed. ##EQU2## where TH1 represents a threshold level of the center clipper. If the residual echo signal e(n)is quite weak, the output signal e(n) is forcibly reduced to zero for enhancing an echo suppressing effect.
On the other hand, the tap coefficient updating unit 21 serves to sequentially update a tap coefficient h i in a manner to reduce the residual echo signal e(n) as small as possible using a learning identification algorithm. With this learning identification algorithm, the tap coefficient h i is updated according to the equation; ##EQU3## And, if a double talk is caused, the double talk detector 25 serves to cancel updating of a tap coefficient h i in the tap coefficient updating unit 21 for avoiding correction of the identified tap coefficient h i .
Next, a description will be directed to the testing operation of making sure of the function of the echo canceller 11. In FIG. 4, the control unit 15 receives a test-starting command from the external except the echo canceller 11 involved in a communications equipment. If the test is determined to be ON in the test ON check at the step 401, it serves to connect the switches SW1, SW2, and SW3 to the terminals 1f, 1g, and 1i sides, respectively. Then, at a step 403, the far-end talker signal generating unit 12 generates a white noise for producing a far-end talker signal r(n). At a step 404, the echo signal generating unit 13 produces an echo signal s(n) for an echo path used for the test. The echo canceller 11 serves to receive the output signal of the far-end talker signal generating unit 12 as a far-end talker signal r(n) and to receive an output signal of the echo signal generating unit 13 as an echo signal s(n).
Further, for making sure of whether or not the system is stable at the testing time, the echo canceller 11 is disabled for predetermined (x) seconds after starting the test in order to stop the operation of the subtracter 36, such that the equation of;
e(n)=s(n)
is performed. After the predetermined (x) seconds are passed since the test is started, the echo canceller 11 is enabled in order to start the operation of the subtracter 38 for the test. If the test is determined to be ON in the test ON check at the step 405, the echo canceller 11 serves to send out the output signal e(n) to the residual echo detector 14 in which a power level of the residual echo signal e(n) is derived. Then, at a step 408, the control unit 15 serves to output a testing result, and the process returns to the step 401.
FIG. 5 is a block diagram showing the far-end talker signal generating unit 12 shown in FIG. 1. As shown in FIG. 5, 51 1 , 51 2 , . . . 51 l each denotes a delayed flip-flop (D-F/F) and 52 denotes an exclusive OR circuit. This far-end talker signal generating unit 12 is serviceable as a white noise generator. The generator consists of a l-bit shift register having a l-stage D-F/F 51 1 to 51 l for generating a white noise. As an initial input, an exclusive OR at a proper stage of the output tap is supplied to the shift register through the exclusive OR circuit 52 and the output of each D-F/F 51 1 to 51 l is drawn to producing a white noise. This white noise signal is input as a far-end talker signal r(n) to the echo canceller 11 as well as the echo signal generating unit 13. The foregoing function can be realized using a program run on the memory and the processors (DSP). And, it is well known that the function of the echo canceller itself can be realized using the DSPs. Hence, it is to be understood that such DSPs can be used for the testing circuit in the present invention. That program should be pre-loaded in ROMs of those processors.
FIG. 6 is a block diagram showing the echo signal generating unit 13 shown in FIG. 1. As shown in FIG. 6, 61 1 to 61 m each denotes a delaying element, 62 1 to 62 m each denotes a multiplier, and 63 denotes an adder. This echo signal generating unit 13 consists of M-stage finite impulse response (FIR) filters simulating an echo path and serves to perform the following operation for producing an echo signal s(n), which is entered into the echo canceller 11. ##EQU4## where a k denotes a filter coefficient.
The echo canceller 11 receiving the far-end talker signal r(n) and the echo signal s(n) operates to presume an echo path (the echo signal generating unit 13 at this testing time) and sends out the output signal s(n) to the residual echo detector 14. The residual echo detector 14 serves to derive a power e pow of the residual echo signal e(n) with the equation of; ##EQU5## This power e pow is input to the control unit 15.
The control unit 15 receiving the power e pow of the residual echo signal e(n) serves to output the following testing results according to the power e pow given in the disabled echo canceller 11 from the test-starting point unit an x-second one. ##EQU6## Further, it also serves to output the following testing results according to the power e pow given in the enabled echo canceller 11 between an x-second time point and an x'-second one since the test is started. ##EQU7## where TH is a constant given according to an echo-cancelling amount of the echo canceller 11 and the level of the white noise generated by the far-end talker signal generating unit 12.
As discussed above, the testing result is provided according to each residual echo given in case of the disabled or the enabled echo canceller 11. Hence, it is possible to detect a state of e=0 in which the echo canceller 11 is failed for producing no output.
The present embodiment makes it possible to test the function of the echo canceller by itself.
FIG. 7 is a block diagram showing a testable echo canceller according to another embodiment of the invention. As shown in FIG. 7, the same reference numbers as those shown in FIG. 1 indicate the same elements. 11 is an echo canceller shown in FIG. 2, 12 is a far-end talker signal generating unit shown in FIG. 5, 13 is an echo signal generating unit shown in FIG. 6, 14 is a residual echo detector, and 15 is a control unit, the operation of which is represented in FIG. 3. 8b and 8d represent input and output terminals, which are used for composing a bypassing circuit for a near-end talker signal along with switches SW4 and SW5, 8a and 8c represent input and output terminals used in the normal echo-cancelling operation.
FIG. 8 is a flowchart showing the operation shown in FIG. 7.
As shown in FIG. 8, in a normal state, if the test for the echo canceller 11 is determined to be OFF in the test ON check at a step 801, at a step 802, the echo canceller 11 serves to connect the switch SW4 to the terminal 8a side and the switch SW5 to the terminal 8c side. Then, at a step 803, the control unit 15 serves to set the test to OFF. In this arrangement, the echo canceller 11 receives a far-end talker signal r(n) at the terminal 1a and an echo signal s(n) at the terminal 1c. Then, it presumes an echo path connected between the terminals 1b and 1c and outputs a residual echo signal e(n) at the terminal 1d.
And, in the testing state, at a step 801, if the test is determined to be ON, the echo canceller 11 serves to connect the switch SW4 to the terminal 8b side and the switch SW5 to the terminal 8d side. Then, at a step 805, it serves to set the control unit 15 to an ON state. Hence, the echo canceller 11 operates to test the function similarly as described in FIG. 1. The echo signal s(n) to be input at the terminal 1c through the echo path bypasses the echo canceller 11, that is, directly leads to the terminal 1d. It results in being able to perform the test without having to interrupt a call/talk.
At a test-completing stage, if the test is determined to be completed in the test completion check at a step 806, the control unit 15 is released from an active testing state at a step 808 and then the echo canceller 11 is reset. Next, at a step 809, the echo canceller 11 serves to switch the switch SW4 to the terminal 8a and SW5 to terminal 8b in a manner to start presuming an echo path connected between the terminals 1b and 1c again from the initial state.
FIG. 9 is a block diagram showing an embodiment of a communications equipment including a testable echo canceller. This embodiment described a multiplexing device to which the testable echo canceller shown in FIG. 7 is applied. As shown, 90 is a multiplexing device, 91 l to 92 n (n is a positive integer) are each trunk circuit, 92 1 to 92 n are each testable echo canceller according to the invention, 93 is a control unit for the echo canceller's, 94 is a multiplexer/demultiplexer unit, and 95 is a high-speed digital line interface circuit.
When the multiplexing device performs the test for the echo canceller 11, the echo canceller control unit 93 serves to issue a test-starting command to the testable echo cancellers 92 l to 92 n . In receipt of the command, each canceller performs the foregoing testing operation and sends out the testing result to the echo canceller control unit 93. With the display of the received testing result, for example, the echo canceller control unit 93 is capable of making sure of the function of the echo canceller 11. Further, for performing the test, the control unit 93 can selectively or serially use those echo cancellers in accordance with the program. In addition, the test can be accomplished in an automatic and steady manner.
As set forth above, the present invention offers an advantage that it is possible to easily make sure of the performance of the echo canceller, because the invention makes it possible to perform the test with the echo canceller itself.
Further, the invention enables the test to be performed while a talk is alive. It thus offers an advantage that it is possible to easily make sure of if the echo canceller functions normally or abnormally without having to block a communications line.
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A communications system adaptive echo canceller integrally contains a test far-end talker signal generator, an echo signal generator for generating an echo signal with a simulated echo path, a residual echo detector for detecting a residual echo based on the output of a subtracter, and a switching unit for switching an input and output signal of the echo canceller into an echo canceller test mode. Further, it provides a bypassing unit for, in a test mode, separating a call/talk connected to the echo cancellers from the echo cancellers and forming a bypass path between trunk circuits and a transmission circuit. The bypassing unit results in being able to realize a test for the echo canceller while a talk is alive.
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BACKGROUND OF THE INVENTION
Starches, and particularly potato starches, are often used commercially to prepare edible food products. Some of those products may, for example, include puddings, pie fillings, gravies, baby foods, salad dressings, and the like.
It is common when preparing such food products to use a chemically cross-linked starch. The reason for using cross-linking agents is that it is well-known in the art that certain starches upon gelatinization will thicken, followed by thinning. This is well-known behavior of starches, believed to be caused by gelatinization to the point where the starch granules implode and fragment, leaving them thin and possibly stringy (long-pasted).
It is, of course, expensive to cross-link natural starches in order to prevent the thinning of starch materials; additionally, there has been some question about the safety of some of the modified starches. There is additionally a market interest in "natural" foods, unmodified by chemicals. Thus it would be desirable to prepare starches which did not need added cross-linkers.
It is a primary objective of the present invention to prepare a potato starch material which does not need to be chemically modified by linking, but yet which will have certain characteristics of a chemically modified starch.
Another objective of the present invention is to prepare food products using as the starch source a potato starch prepared from Pontiac potatoes as the primary starch source. Examples of such food products include puddings, pie fillings, gravy mixes, soups, and the like.
The method of accomplishing each of these, as well as other objectives for the present invention will become apparent from the detailed description which will follow hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an amylograph curve comparing the Pontiac potato starch of the present invention with other starches from other potatoes from the standpoint of viscosity.
DETAILED DESCRIPTION OF THE INVENTION
This invention is premised upon the discovery that Pontiac potato starch behaves abnormally in an amylograph in comparison with other starches. In particular, it is common for potato starches to undergo gelatinization, followed by thinning, and a decrease in viscosity after either holding at higher temperatures or after introducing shear. Such behavior is illustrated in an amylograph.
Pontiac potato starch does not behave typical of other starches. It is believed that this property of Pontiac potato starch was not heretofore known. The invention is premised upon the discovery that this abnormal behavior of Pontiac potato starch can be taken advantage of in desirable ways.
In particular, one can prepare food products using as the major portion of the starch Pontiac potato starch. When this is done, it eliminates the need for cross-linking the starches ordinarily used to prevent the undesirable results occurring after prolonged holding and/or heating and/or inducing of shear after gelatinization.
The starch of this invention is Pontiac potato starch, and as such it is known. However, this ability of the natural starch to be resistant to starch thinning and to have a shorter-textured paste is not known. This abnormal behavior allows Pontiac potato starch to be used without the necessity for added chemical cross-linking treatment. For example, when Pontiac potato starch is used as a major starch source in edible food products that contain potato starch mixes, such as gravy mixes, pudding mixes, pie fillings, soups and other starch-based edible food product mixes, there is no need for additional thickening agents that have undergone the chemical treatment. Chemical cross-linking is commonly utilized because texture is controlled during shear, heat and acid conditions. As a result, the products can be made less expensively. They are also more nearly natural.
The amount of Pontiac potato starch used is merely a function of the thickness desired. One can use up to 100% Pontiac potato starch. Preferably, the amount of Pontiac potato starch should be a major portion, that is, at least 50% of the starch mixture, and it can be up to 100%. Preferably the amount will be 70%, more preferably 80%, and in some instances 90% or 100%. The amount used is simply a matter of economics and characteristics desired for the given food product. The requirements for added thickening agents relate inversely to the amount of Pontiac potato starch. Put another way, at lower levels it may be necessary for some added thickening agent, but at higher levels there is a need for none.
The examples which will follow hereinafter are illustrative of showing of a relationship between the texture of four potato cultivars and the properties of the potato starches and juices and to specific gravity at the time of shear. They show abnormal behavior with regard to the amylograph for Pontiac potato starch.
EXAMPLES
Russet Burbank and Norchip cultivars, commonly utilized as examples of high-specific-gravity, mealy potatoes, and red-skinned Pontiac and LaSoda cultivars, commonly used as typical low-specific-gravity, waxy potatoes, were selected.
For starch isolation, stem halves of peeled potatoes (eyes and blemishes removed) were cut into pieces and shredded in an Acme Juicerator (Model 6001). Juice was collected, centrifuged to remove starch granules, and frozen immediately. The pulp was rinsed with distilled water in the juicerator, then transferred to a Waring blender with additional distilled water for thorough maceration. The mixture was placed on graduated mesh screens and washed numerous times with distilled water to separate starch from the pulp. Rinse water was centrifuged to recover starch granules. Starch was rinsed with distilled water, dried, powdered and stored. Scanning electron microscopy indicated the starch granules were undamaged.
In an amylograph, suspensions of 3.25% starch (dry basis) in distilled water were heated at a constant temperature increase of 1.5° C. per min from 30° C. to 95° C., held at 95° C. for 15 min, then cooled at a constant temperature decrease of 1.5° C. per min to 50° C.
Swelling powers were conducted by modification of the method described by Schoch, Methods in Carbohydrate Chemistry, Vol. IV, Academic Press, p. 106 (1964). Two series of tests were run, varying the amount of starch and time of heating. All starch used was from the 1984 potatoes. Each starch, 0.5 g (dry substance), was placed in a centrifuge bottle with a magnetic stirring bar and 200 g distilled water. Bottles with starch from each of the four potato cultivars were heated together in water baths at 75° C., 80° C. and 85° C., with only enough agitation to keep the slurries suspended. After 30 min heating, the samples were centrifuged for 20 min at 190×g. To allow thickening of the precipitated layer and hence better separation, samples were chilled for 16-20 hr before the supernatant was removed. An aliquot was dried to give percentage soluble starch. The swelling power was determined by dividing the weight of the swollen starch layer by the weight of the dry starch used. The corrected swelling power was calculated. Because of the difficulty in separation, 20 replicates were used.
The statistics used to separate the means were ordinary t-tests rather than more conservative range tests. The comparisons were only among four means and the use of range tests would lead to substantially the same conclusions.
SWELLING POWER
Swelling powers of potato starch were so high above 85° C. that the supernatant layer was poorly distinguished and 85° C. was the highest temperature used.
As the temperature was elevated, the swelling powers and percentage solubles increased (Table 1). The mealy potato starches (Russet and Norchip) exhibited nearly the same swelling powers and percentage solubles, but the waxy potato starches differed from one another. LaSoda starch swelled the most, though the percentage solubles was almost identical to that from Russet Burbank starch. Values for LaSoda cultivar at 85° C. seemed to show lower swelling; however, the syrupy appearance of the swollen granules indicated much greater swelling at that temperature; accurate separation of the layers was impossible. Swelling of pontiac starch was significantly lower than any of the others.
Amylograph
The minimal swelling of the Pontiac starch could also be seen in the amylograph comparisons (FIG. 1). Unrau and Nylund, supra, using lyophilized potato tissue, found that the Pontiac potato attained a lower maximum Brabender viscosity than two cultivars judged to be mealy. FIG. 1 also showed that Pontiac starch was the only cultivar that did not attain a peak viscosity and that increased in viscosity during the 15-min holding period at 90° C. After cooling to 50° C., Pontiac starch was thickest of the four starches and was at its maximum viscosity. The other starches were not distinguishable from one another based on viscosity.
TABLE 1__________________________________________________________________________Swelling powers, solubles and correctedswelling powers of starches fromfour potato cultivars (1984) CorrectedTemp. Swelling Percent SwellingCultivar(°C.) Power Mean Soluble Mean Power Mean__________________________________________________________________________Russet75 60 13.8 6980 95 93.sup.a 19.8 18.6.sup.mn 119 115.sup.x85 121 21.8 155Norchip75 74 13.7 87 125.sup.xy80 95 99.sup.ab 19.5 19.6.sup.m 11985 127 25.6 170Pontiac75 46 10.9 51 82.sup.z80 70 70.sup.c 13.7 13.8° 8285 92 16.8 111LaSoda75 88 13.2 10380 124 111.sup.b 18.8 17.5.sup.n 153 135.sup.y85 115 20.1 144__________________________________________________________________________ .sup.1 In a given column, means with the same superscript are not significantly different based on a ttest (P < 0.05).
It can be seen from the above data that Pontiac potato starch was more resistant to swelling than the starches from other cultivars, and that it was more resistant to thinning.
Using the Pontiac potato starch without any added cross-linkers at the percentage levels specified, one may prepare successfully a number of food products which are equally as good as the conventional produces with chemically cross-linked starches. Such products include puddings, pie fillings, gravies, baby foods and salad dressings.
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A method of preparing edible food product mixes that ordinarily require chemically cross-linked starch by preparing them from a major amount of Pontiac potato starch which has not been chemically cross-linked.
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BACKGROUND OF THE INVENTION
The invention relates to offshore oil production apparatus and in particular to a connector for connecting a tieback conductor to a wellhead.
Offshore oil wells may be drilled from a floating platform and thereafter produced to a later constructed, fixed platform. Such a procedure requires the running of tieback conductors from the platform deck to the wellhead. Tubing is then run, surface production trees installed, and the wells produced in the conventional manner.
One conductor, and possibly other concentric conductors, is run to the wellhead from each platform. The largest or outermost conductor is connected and sealed to the wellhead. Horizontal offset may occur between the wellhead centerline and the corresponding platform well location. Angular misalignment between the wellhead and the guidance system of the conductor often occurs. Although the conductor string runs through guides located on the platform structure at various elevations, offset may occur as a result of inherent manufacturing and installation tolerances. Centralizers may be eccentrically located on the conductor to compensate for this misalignment.
The problem remains, however, of angular misalignment between the conductor and the wellhead as the conductor approaches the wellhead. Existing tieback tools cannot be engaged if the angular misalignment exceeds 0.5 degrees. Attempts to make up the joint may result in damage to the threads.
Seals are provided between the conductor connector and the wellhead. Rotation of the conductor for make up causes rubbing of the seal under compression with potential damage to the seal. Rotation of the string is cumbersome and does not allow the use of eccentric centralizers affixed to the conductor.
SUMMARY OF THE INVENTION
A conductor tieback connector for connecting a conductor to a subsea wellhead includes a tubular body which is connectable to the lower end of a conductor. A downwardly extending funnel is attached to the body and has two internal bearing surfaces, one located near the body and the other remote from the body. The funnel also includes a tapered guide at its lower end.
The tapered guide aids in initial stabbing of the connector over the wellhead, and the two bearing surfaces operate on the outside surface of the wellhead to force the conductor into angular alignment under the influence of the weight of the conductor. The internal diameter of the connector between the two bearing surfaces is greater than the diameter at each of the bearing surface locations with gradual slope in diameter occurring immediately below the upper bearing surface. Seals are located between the connector and the wellhead which are compressed with axial movement of the connector.
The bearing surfaces first act to bring the connector into accurate alignment with the wellhead. Thereafter, a lockdown means engages the wellhead and clamps the connector into precise alignment and compresses the seals. An internal floating bushing which is threadable with the interior surface of the wellhead permits this lockdown and clamping operation to the carried out without rotation of the conductor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates the connector as it approaches the wellhead,
FIG. 2 illustrates the connector in the seated position, and
FIG. 3 illustrates the assembled connection as fully engaged.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A plurality of wells may be drilled from a floating platform while a fixed platform is being constructed. Each of the wells has a wellhead 10 located near the seabed. Once a well is drilled to depth, it is plugged, a protective cap installed, and the floating, drilling vessel moved to another well location preferably on a common drilling template.
Tieback of the subsea wells to the platform begins immediately after the platform installation is complete. The external conductor 12 is to be connected and sealed to the wellhead 10. The conductor tieback connector 14 is threadably connected and sealed to the conductor 12. This connector includes an upper tubular body 16 including seal grooves 18 at a location where seal rings may be contained for sealing with the wellhead 10.
The lower portion of the connector includes a funnel 20 which is securely attached to the tubular body and is a part of a single weldment. This funnel may include on its outer surface a plurality of guide ribs 22 which are tapered at the lower end faring uniformly into a tapered surface 24 at the lower end of the cylindrical funnel 20. If the connector approaches the wellhead with some horizontal offset, the lower edge of the guide ribs 22 interact with a tapered surface 26 at the upper edge of the wellhead. The weight of the conductor forcing the connector downwardly causes the conductor to deflect laterally and encircle the wellhead 10. The funnel includes a first and lower bearing surface 28 which has an internal diameter only slightly greater than the outside diameter of the wellhead. This provides accurate guidance of the lower end of the connector.
An upper bearing surface 30 also has a diameter only slightly greater than the outside diameter of the wellhead. The funnel at an intermediate location 32 between the first and second bearing surfaces has a diameter greater than that of either of the surfaces. The diameter gradually approaches that of the second bearing surface at the sloped internal diameter location 34.
As the connector is lowered with the first bearing surface 28 engaged, the internal surface 32 rides at the top of wellhead 22 followed by the sloped surface 34 and ultimatelythe upper bearing surface 30. Interaction between the two bearing surfaces and the outside surface of the wellhead applies a bending moment to force the conductor into alignment with the wellhead. The weight of the conductor applies the driving force, which may be augmented with a connector tool described hereinafter. Selection of tolerances between the various diameters should be such that this forces axial alignment within preferably 0.1 degrees.
At this time abutting surfaces of the wellhead and connector contact, and seals 36 located within grooves 18 are compressed against the upper surface 38 of the wellhead. Only the weight of the conductor string operates to compress the seal.
The interior surface of the wellhead 10 contains screw threads 40. A floating bushing 42 has lower external threads 43 adapted to mate with threads 40. The conductor connector 14 also includes upper internal threads 44, which mate with upper external threads 45 of the floating bushing 42.
These upper threads operate to support the bushing in a withdrawn and protected position during the running of the conductor. Prior to sealably connecting the connector 14 to the conductor 12 at joint 46, the bushing 42 is inserted from the top of the connector and rotated into engagement with threads 44. The inside diameter 47 of the connector below the threads 44 is greater than the outside diameter of threads 45, so that the bushing may be later rotated to pass through the threads.
The bushing includes vertical slots 50 which provide a means for interlocking the bushing with a rotating tool 52. This rotating tool includes spring activated latches 54 which engage the vertical slots. A tubing string, carrying tool 52 may be run down and the tool used to rotate the bushing thereby releasing the bushing from its upper position. The longitudinal spacing of the threaded sections is such that the bushing is released from engagement between threads 44 and 45 before threads 40 and 43 engage. This provides a floating position of the bushing which facilitates engagement of the lower threads. Further rotation of the bushing compresses the connector against the wellhead through the action of shoulders 53 and 55. The connector is thus brought into precise alignment, and the seals further compressed. This brings the connection into precise alignment through the interaction at slope 26 of the wellhead and further compresses the seals.
The conductor tieback connector also includes an internal land 56 which provides a sealing surface. When the torque tool is landed, it rests on shoulder 58 of the bushing. With the bushing in its supported position, the seal rings 60 of the torque tool are then at an elevation where they will seal against the land 56. Accordingly, a low pressure tightness test may be run before releasing and tightening the bushing, by attempting to pressurize the interior of the conductor.
If a seal has not been effected under the weight of the conductor, additional force may be applied using torque tool weight thru the bushing. Drill collars on the running string of the torque tool may be used for this purpose. After it is determined that the connector is properly sealed, the bushing is rotated free of threads 44 and torqued into threads 40, as described above.
The conductor tieback connector permits engagement between the conductor and the wellhead with some horizontal offset and with significant angular misalignments. The bearing surfaces of the funnel operate to generate a bending moment which brings the conductor into alignment with the wellhead and, accordingly, brings the threaded bushing into alignment, whereby the threaded connection may be safely made without cross threading or damaging of threads. The conductor connector is also adaptable to interact with the torque tool to permit a low pressure test of the conductor to verify full engagement of the connector over the wellhead prior to securing the connection with the floating bushing. Furthermore, the connection is made without any rotation of the conductor 12 and any rotational wear on seals 36.
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A conductor tieback connector for connecting a conductor to a subsea wellhead includes a downwardly extending funnel. Two bearing rings within the funnel interact with the outside surface of the wellhead to generate bending forces to force the tool in alignment with the wellhead. Thereafter a separate lockdown nut secures the connector to the wellhead without rotation of the conductor.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority of Korean Patent Application No. 10-2011-0049725 filed on May 25, 2011, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method for providing information for diagnosing cancer using a quantitative Real-Time PCR and a kit for diagnosing cancer for the same.
[0004] 2. Description of the Related Art
[0005] Our country currently has the highest death rate from cancer so that cancer is an important disease; and cancer development is increasing every year and our country reported a cancer rate of at least 300 per 100,000 in 2008 (Jemal, A.; Siegel, R.; Xu, J.; Ward, E., Cancer statistics, 2010. CA Cancer J Clin 2010, 60, (5), 277-300).
[0006] In the case of the early stage of cancer, most malignancies can be cured by a simple operation or a drug treatment, but if cancer has spread to other organs, the cancer is difficult to treat, and also the prognosis and the survival rate after 5 years of patient are decreasing. In the case of the metastatic cancer as mentioned above, a cancer cell presented in the initial solid cancer comes out of the original lesion to settle in other organs through a lymph node, a blood stream, or a born-marrow thereby inducing the metastatic cancer. The cancer cell presented in the blood stream as mentioned above is called a circulating tumor cell (Ross, J. S.; Slodkowska, E. A., Circulating and disseminated tumor cells in the management of breast cancer. Am J Clin Pathol 2009, 132, (2), 237-45).
[0007] The circulating tumor cell is called a minority of tumor cells that come out of the primary tumor tissue and then get around through the blood flow, and it may get around in the blood and then may cause metastatic cancer at a secondary region. Therefore, the diagnosis of the circulating tumor cell may be effectively used for detecting as to whether the cancer has expanded for a patient with early stage cancer. Since it is generally known that the progress of the patient with the metastatic cancer can react badly to the treatment and the prognosis after the operation is bad, the diagnosis of the circulating tumor cell is being used as a good marker for detecting the progress or the prognosis of the patient because it can help to measure as to whether the cancer of the patient can be progressed to the metastatic cancer (Meng, S.; Tripathy, D.; Frenkel, E. P.; Shete, S.; Naftalis, E. Z.; Huth, J. F.; Beitsch, P. D.; Leitch, M.; Hoover, S.; Euhus, D.; Haley, B.; Morrison, L.; Fleming, T. P.; Herlyn, D.; Terstappen, L. W.; Fehm, T.; Tucker, T. F.; Lane, N.; Wang, J.; Uhr, J. W., Circulating tumor cells in patients with breast cancer dormancy. Clin Cancer Res 2004, 10, (24), 8152-62; Pachmann, K., Longtime recirculating tumor cells in breast cancer patients. Clin Cancer Res 2005, 11, (15), 5657; author reply 5657-8).
[0008] In addition, the cancer cell has a significantly fast differentiation speed of cell unlike a general cell. Therefore, if it is expressed by using the marker used for the cell differentiation that the differentiation speed is faster, it can be found that there are certain diseases and disorders.
[0009] Currently, a method for a diagnosis of metastatic cancer is being made by detecting as to whether a cancer cell is presented using a detecting method by an invasive lymph node, and an image equipment, such as MRI and PET. However, it has a limitation that the detecting method as mentioned above can use in the case of the metastatic cancer. However, the prognosis management of the cancer patient may be carefully made by diagnosing the patient that has a possibility to expand among the patients with early stage cancer that have not expanded by testing as to whether the circulating tumor cell is presented.
[0010] An antigen-antibody detecting method using the difference between the surface antigens of cancer cells and blood cells is very popular. The surface of cancer cells has the epithelium antigen, as distinct from the blood cells. The antigens as mentioned above are presented on the epithelium cell, but are not presented at the interior wall of blood vessel and the blood cells. Especially, it is known that Cytokeratin 19 among the antigens as mentioned above is expressed on breast cancer, bladder cancer, cervical cancer, colorectal cancer, lung cancer, pancreatic cancer, stomach cancer, and the like (Karantza, V., Keratins in health and cancer: more than mere epithelial cell markers. Oncogene 2011, 30, (2), 127-38). Therefore, a method for diagnosing the circulating tumor cell is currently being used using Cytokeratin 19 antigen. As a method for diagnosing that is currently being used, CellSearch from Veridex Inc. is the most commonly used, in which the method is to test as to whether the circulating tumor cell is presented using Pan-Cytokeratin antibody after distinguishing the cells that are negative to CD45 and positive to EpCAM through Antigen-antibody binding reaction using a fluorescent-marked antibody (Allard, W. J.; Matera, J.; Miller, M. C.; Repollet, M.; Connelly, M. C.; Rao, C.; Tibbe, A. G.; Uhr, J. W.; Terstappen, L. W., Tumor cells circulate in the peripheral blood of all major carcinomas but not in healthy subjects or patients with nonmalignant diseases. Clin Cancer Res 2004, 10, (20), 6897-904). However, the technique as mentioned above is currently not introduced in our country, and also it has a limitation that it requires expensive equipment. In addition, a method for diagnosing the circulating tumor cell based on RT-PCR that is now developed has limitations because it detects the bands of amplified fragments using an electrophoresis, as follows: the specificity is low; the experiment process is complicated, and the quantitative results are difficult to obtain. Therefore, the present inventors invented a new method for diagnosing the circulating tumor cell based on Real-time RT-PCR that can obtain a simple and a quantitative result by targeting mRAN not Antigen-antibody reaction in order to replace the above mentioned technique.
SUMMARY OF THE INVENTION
[0011] The present invention is for solving the above limitations and invented for the above needs, and an object of the present invention is to provide a method for diagnosing a circulating tumor cell based on Real-Time RT-PCR.
[0012] Another of the present invention is to provide a kit for diagnosing the circulating tumor cell.
[0013] In order to achieve the above objects, the present invention provides a method for providing information for diagnosing cancer, comprising: a) isolating full-length RNA from cells (all cells except a red blood cell) obtained from blood of a patient suspicious for cancer; b) synthesizing cDNA from the isolated full-length RNA; c) performing Real-Time PCR with the synthesized cDNA using at least one primer pair and probe selected from the group consisting of a primer pair and a probe that can amplify Cytokeratin 19, a primer pair and a probe that can amplify Ki67, and a primer pair and a probe that can amplify TBP; and d) comparing the amplified amount of the above step with the amplified amount of the normal.
[0014] A method for isolating full-length RNA (Total RNA) and a method for synthesizing cDNA from the isolated full-length RNA that are generally used can be performed through the known method, and the detailed description about the process is disclosed in Joseph Sambrook et al., Molecular Cloning, A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (2001); and Noonan, K. F., and the like, which may be incorporated in the present invention as a reference.
[0015] The primer of the present invention can be chemically synthesized using a phosphoramidite solid support method, or other known methods. The nucleic acid sequence may be also modified by using many ways that are known in the prior art. The non-limited example of the modifications may be a methylation, “a capping,” a substitution with at least one homologue of natural nucleotide, and the modification between nucleotides, for example, the modification to a non-charged linker (For example: methyl phosphonate, phosphotriester, phosphoroamidate, carbamate, and the like) or a charged linker (For example: phosphothioate, phosphorodithioate, and the like). Nucleic acid may include at least one additionally covalent bonded residue, for example, protein (For example: nuclease, toxin, antibody, signal peptide, poly-L-lysine, and the like), an intercalating agent (For example: acridine, psoralens, and the like), a chelating agent (For example: metal, radioactive metal, iron, oxidative metal, and the like), and an alkylation agent. The nucleic acid sequence of the present invention may be also modified with the marker that can directly or indirectly provide a detectable signal. Example of the marker may include a radioactive isotope, fluorescence molecular, a biotin, and the like.
[0016] For the method according to the present invention, the amplified target sequence (Gene, such as Cytokeratin 19, Ki67, and the like) may be marked with a detectable marker material. For one embodiment, the marker material may be the material that emits a fluorescence, a phosphorescence, a chemiluminescence, and a radioactivity, but limited thereto. Preferably, the marker material may be fluorescein, phycoerythrin, rhodamine, lissamine Cy-5 or Cy-3. The marker material may be marked with a detectable fluorescent marker material by performing Real-Time RT-PCR through marking Cy-5 or Cy-3 to 5′-end and/or 3′-end of primer when amplifying a target sequence.
[0017] In addition, the marking using the radioactive material may be achieved by marking the amplified fragment with a radioactivity through incorporating the radioactivity to the amplified fragment while synthesizing the amplified fragment by adding a radioactive isotope, such as 32 P or 35 S to PCR reaction solution when performing Real-Time RT-PCR. At least one oligonucleotide primer set that is used for amplifying the target sequence may be used.
[0018] The marking may be performed through various methods that are typically performed in the art, such as, a nick translation method, a random priming method [Multiprime DNA labelling systems. booklet, “Amersham” (1989)], and a kination method [Maxam & Gilbert, Methods in Enzymology, 65:499 (1986)]. The marker provides a detectable signal by fluorescence, a radioactivity, a chromophore measurement, a weight measurement, X-ray diffraction or absorption, magnetism, an enzymatic activity, amass analysis, a binding affinity, a hybridization high frequency, and a nano crystal.
[0019] According to one aspect of the present invention, the present invention measures the level of expression in the level of mRNA through RT-PCR. To achieve this, new primer pair and fluorescent-marked probe that are specifically bonded to Cytokeratin 19, Ki67, and TBP genes are required; the primer and probe specified with the specific base sequence for the present invention can be used, but not limited thereto; if they provide the detectable signal by specifically binding to those genes and can perform Real-Time RT-PCR, they can be used without limit. In the above sentence, FAN and BHQ1 mean a fluorescent dye.
[0020] Real-Time RT-PCR method applied for the present invention can be performed through the known process that is typically used in the art.
[0021] The measuring of mRNA expression level can be used without limit if it can measure a general mRNA expression level, and according to a type of used probe markers, it can be performed through a radioactivity measurement, a fluorescence measurement, or a phosphorescence measurement, but not limited thereto. As one of methods for detecting an amplified fragment, a fluorescence measuring method can be performed as follows: Cy-5 or Cy-3 is marked to 5′-end of primer and then Real-Time RT-PCR is performed with the marked primer to mark a fluorescent marker material to a target sequence; and then the marked fluorecence can be measured using a fluorometer. In addition, the radioactivity measuring method can be performed as follows: when performing Real-Time RT-PCR, an amplified fragment is marked with a radioactivity isotope, such as 32 P or 35 S, and the like by adding the radioactivity isotope to PCR reaction solution, and then the radioactivity can be measured using a radioactivity measuring instrument, such as Geiger counter or
Liquid Scintillation Counter.
[0022] According to one preferable embodiment of the present invention, a fluorescent-marked probe is attached to PCR product amplified through the Real-Time PCR to fluoresce a specific wavelength; the expression levels of mRNAs of genes according to the present invention are measured in real time with a fluorometer of Real-Time PCR apparatus at the same-time with the above amplification; and then the measured values are calculated and visualized through PC so that a tester can easily confirm the expression levels.
[0023] According to one embodiment of the present invention, the comparing of the above amplified amount with the amplified amount of the normal is preferably performed by a standard or Cut-Off value, and for the Cut-Off value, Ct value (Threshold Cycle) is more preferably 34.0, but is not limited thereto.
[0024] According to another embodiment of the present invention, preferably, the primer pair has the base sequences that are disclosed as Sequence Nos. 1 & 2 and the probe has the base sequence that is disclosed as Sequence No. 3, in which the primer pair and the probe can amplify Cytokeratin 19.
[0025] Preferably, the primer pair has the base sequences that are disclosed as Sequence Nos. 4 & 5 and the probe has the base sequence that is disclosed as Sequence No. 6, in which the primer pair and the probe can amplify Ki67.
[0026] Preferably, the primer pair has the base sequences that are disclosed as Sequence Nos. 7 & 8, and the probe has the base sequence that is disclosed as Sequence No. 9, in which the primer pair and the probe can amplify TBP.
[0027] However, the above primers and the probes are not limited thereto.
[0028] Additionally, the present invention provides a primer pair and a probe for diagnosing cancer, including at least one primer pair and probe selected from the group consisting of: a primer pair having the base sequences that are disclosed as Sequence Nos. 1 & 2 and the probe having the base sequence that is disclosed as Sequence No. 3, which can amplify Cytokeratin 19; a primer pair having the base sequences that are disclosed as Sequence Nos. 4 & 5 and the probe having the base sequence that is disclosed as Sequence No. 6, which can amplify Ki67; and a primer pair having the base sequences that are disclosed as Sequence Nos. 7 & 8 and the probe having the base sequence that is disclosed as Sequence No. 9, which can amplify TBP.
[0029] Additionally, the present invention provides a composition for diagnosing cancer, including the primer pair and probe according to the present invention.
[0030] According to one embodiment of the present invention, the cancer may be preferably breast cancer, bladder cancer, cervical cancer, colorectal cancer, lung cancer, pancreatic cancer, stomach cancer, ovarian cancer, blood cancer, liver cancer, prostate cancer, or head and neck cancer, but is not limited thereto.
[0031] Additionally, the present invention provides a kit for diagnosing cancer, including the composition according to the present invention.
[0032] According to another aspect of the present invention, the kit for diagnosing may be a kit for diagnosing cancer, in which the kit for diagnosing includes essential ingredients that need for performing RT-PCR. RT-PCR kit may include each specific primer pair to the genes according to the present invention. The primer is a nucleotide having a specific sequence to nucleic acid sequence of each marker gene; the length of the primer may be about 7 by to 50 bp, more preferably about 10 by to 30 bp; and more preferably the primer may include new primer pair that is expressed as Sequence Nos. 1 & 2 and a fluorescent-marked probe that is expressed as Sequence No. 3; new primer pair that is expressed as Sequence Nos. 4 & 5 and a fluorescent-marked probe that is expressed as Sequence No. 6; and/or new primer pair that is expressed as Sequence Nos. 7 & 8 and a fluorescent-marked probe that is expressed as Sequence No. 9.
[0033] And also, RT-PCR kit may include a test tube or other proper container, a reaction buffer (pH and magnesium concentration are varied), deoxynucleotide (dNTPs), Taq-polymerase, and enzyme, such as a reverse transcriptase, DNAse, RNAse inhibitor, DEPC-water, a sterilized water, and the like.
[0034] The term, “Method for providing information for diagnosing cancer” in the present invention is a preliminary stage for diagnosing to provide objective basic information required for diagnosing cancer, but not include a clinical judgment and opinion by a doctor.
[0035] The term, “Primer” indicates a nucleic acid sequence having a short free 3′ hydroxyl group; can form a complementary template and base pair; and indicates a short nucleic acid sequence having the function of starting point in order for the template strand transcription. The primer can start DNA synthesis under presence of different four nucleoside triphosphates and the reagent for a polymerization (that is, DNA polymerase or reverse transcriptase) in a proper buffer solution and at a proper temperature. The primer according to the present invention is sense and anti-sense nucleic acid having 7 to 50 nucleotide sequences, which is each marker gene-specific primer. The primer may be incorporated with an additional feature that cannot change a basic property of primer that acts as a starting point of DNA synthesis.
[0036] The term, “Probe” is a single chain nucleic acid molecular, and includes a complementary sequence to a target nucleic acid sequence.
[0037] The term, “Real-Time RT-PCR” is a molecular-biological polymerization method to quantitatively detect the signal generated at the marker of the target probe, in which the target is amplified using a target probe including a target primer and marker using cDNA as a template, and the cDNA is produced after Reverse-transcription of RNA with a complementary DNA (cDNA) using a reverse transcriptase.
[0038] Hereinafter, the present invention will be described.
[0039] The present inventors provides a test method that can confirm the potential metastatic cancer patients by testing as to whether circulating tumor cells are presented after collecting one-tube of blood from cancer patient, in which the metastatic cancer cannot be detected with the existed image equipment. Especially, there are advantages that since the method uses a method for amplifying a gene using mRNAs of Ki67 that is a cell division marker and Cytoketatin 19 that is an epithelial antigen, it can detect the unseeable amount and since it does not use Antigen-Antibody reaction, it is very cheap method.
[0040] Hereinafter, the present invention will be described in more detail.
[0041] Confirmation as to Whether Cytokeratin 19 and Ki67 are Expressed in Each of Cell Lines
[0042] It was confirmed as to whether Cytokeratin 19 and Ki67 were expressed using cell lines that are corresponded to each of cancer cells. The cell lines used included three types of breast cancer-cell line (MCF7, SKBR3, MDA-MB 231), lung cancer-cell line (A549), cervical cancer-cell line (HeLa), and ovarian cancer-cell line (SKOV3), and also human monocyte-cell line (THP-1) was used as a negative control.
[0043] The cell number of each cell line was maintained at 100,000 to confirm the expression aspect of Cytokeratin 19 per cell line. As a result, it could be found that Cytokeratin 19 was highly expressed in the breast cancer-cell line and lung cancer-cell line and was not expressed in the ovarian cancer-cell line and monocyte-cell line. It could be also found that Ki67 was expressed in all of cancer cells.
[0000]
TABLE 1
Clinical Specimen
Cytokeratin 19
Well
Name
(Ct value)
Note
A
MCF7
20.62
Breast Cancer
B
SKBR3
21.30
Breast Cancer
C
MDA-MB 231
24.65
Breast Cancer
D
A549
27.17
Lung Cancer
E
HeLa
34.66
Cervical Cancer
F
SKOV3
Undetermined
Ovarian Cancer
G
THP-1
Undetermined
Monocyte
H
Blank control
Undetermined
[0044] Table 1 shown the expression aspects of Cytokeratin 19 per cell lines.
[0000]
TABLE 2
Clinical Specimen
Ki67
Well
Name
(Ct value)
Note
A
MCF7
23.49
Breast Cancer
B
SKBR3
23.65
Breast Cancer
C
MDA-MB 231
22.91
Breast Cancer
D
A549
26.64
Lung Cancer
E
HeLa
25.03
Cervical Cancer
F
SKOV3
31.82
Ovarian Cancer
G
THP-1
23.00
Monocyte
H
Blank control
Undetermined
[0045] Table 2 shown the expression aspects of Ki67 per cell lines.
[0046] Confirmation as to Whether Ki67 is Expressed, Cut-Off Value Set-Up, and Sensitivity of Cytokeratin 19 Expression
[0047] 10 ml of blood was collected from healthy human without cancer, a model of circulating tumor cell was intentionally prepared by mixing from 10 5 to 1 cell of MCF7 that was the breast cancer-cell line with the above collected blood by stages, and then the sensitivity was confirmed. In addition, Cut-Off value was experimentally set-up using the blood of healthy human without cancer. As a result, 10 per 10 ml in the circulating tumor cell intentionally prepared could be detected, and also Cut-Off value of Ct value could be set-up as 34.0.
[0048] In the case of Ki67, after TBP (TATA BOX BINDING Protein) and Ki67 were amplified, respectively, Ct values were measured, and then the expression aspects were confirmed based on the normal 4 . The expression aspects were confirmed from 1.0 to 3.27.
[0049] TBP in the present invention was used as Internal control. In the case of Ki67, TBP was added at all times in order to set the standard unlike Cytokeratin 19 (As to whether Cytokeratin 19 is expressed can be confirmed by detecting a relative cell number through preparing a quantitative curve using the circulating tumor cell model as a standard) and TBP and ki67 were added at all times based on DNA with the same concentration with Ct value of TBP of the normal in order to compare the expression amount of the normal. When at least 10 times was expressed after the standard of TBP was set-up to 1, it was tested the positive.
[0000]
TABLE 3
Clinical
Cytokeratin 19
Specimen Name
(Ct value)
Relative Cell No.
Blood + MCF7 10 5
20.6
100000.0
Blood + MCF7 10 4
24.0
10000.0
Blood + MCF7 10 3
28.2
1000.0
Blood + MCF7 10 2
31.4
100.0
Blood + MCF7 10
32.0
10.0
Blood + MCF7 1
34.0
1.0
Normal 1
34.8
Normal 2
35.1
Normal 3
37.2
Normal 4
35.9
[0050] Table 3 shown the sensitivities of circulating tumor cells models.
[0000]
TABLE 4
Clinical Specimen
TBP
Ki67
Name
(Ct value)
(Ct value)
Expression
Normal 1
27.10
31.6
1.77
Normal 2
28.71
31.0
3.29
Normal 3
27.80
31.9
2.77
Normal 4
27.0
32.6
1.00
[0051] Table 4 shown Ki67 expressions of the normal.
[0052] Confirmation of Ki67 and Cytokeratin 19 in the Blood of the Patient with Metastatic Breast Cancer
[0053] It was confirmed as to whether Cytokeratin 19 was expressed after receiving the blood of the patients with the metastatic breast cancer from Sinchon Severance Hospital. After a quantitative curve was prepared using the arbitrary circulating tumor cell model used for the above test as a standard, a relative cell number was confirmed. As a result, there was one patient, in which at least 10 of the circulating tumor cell among total 6 patients was detected, and there was two patients having not more than Cut-off value but not at least 10 of the circulating tumor cell.
[0054] In addition, it could be found that Ki67 was highly expressed in the patient group that shown high Cytokeratin 19 expression as compared with the normal. Considering maximum 3.29 of expression rate of the normal, it could be found that Ki67 was expressed at a high rate in the patient group 4 and patient group 6, respectively. Therefore, when detecting using two markers at the same time, the positive ratio can be more increased so that it could be more easily used for observing the cancer patients who could develop the metastatic cancer.
[0000]
TABLE 5
Clinical Specimen
Cytokeratin 19
Name
(Ct value)
Relative Cell No.
Blood + MCF7 10 5
20.6
100000.0
Blood + MCF7 10 4
24.0
10000.0
Blood + MCF7 10 3
28.2
1000.0
Blood + MCF7 10 2
31.4
100.0
Blood + MCF7 10
32.0
10.0
Blood + MCF7 1
34.0
1.0
Patient Group 1
34.4
1.9
Patient Group 2
34.4
1.8
Patient Group 3
33.8
3.0
Patient Group 4
30.7
43.9
Patient Group 5
35.4
0.8
Patient Group 6
33.7
3.2
[0055] Table 5 is a table for detecting the circulating tumor cell in the patients with metastatic breast cancer.
[0000]
TABLE 6
Clinical Specimen
TBP
Ki67
Ki67
Name
(Ct value)
(Ct value)
Expression rate
Patent Group 1
26.9
30.5
4.08
Patent Group 2
26.0
29.2
5.47
Patent Group 3
27.0
31.5
2.0
Patent Group 4
29.6
31.2
16.0
Patent Group 5
27.5
31.9
2.3
Patent Group 6
29.6
31.0
18.4
[0056] Table 6 shown the expression aspects of Ki67 in the patient groups.
[0057] Comparison with Existed Known RT-PCR Method
[0058] In order to compare with a method for detecting the circulating tumor cell using the existed known RT-PCR method, the comparison experiment with Primer Set that was already used in other patent was performed. As a result, in the case of the existed known primer set, it could be found that the band with the same size as the band of Cytokeratin 19 was presented in the normal clinical specimen 4, but when using Real-Time PCR method used for the present invention, it could be not confirmed as to whether it was expressed, so that it could be found that the new developed primer and probe set had high specificity as compared with the existed known RT-PCR. In addition, the step for confirming the band using an electrophoresis was not required so that it had an advantage such that the result could be easily found.
[0059] The present invention can confirm the potential metastatic cancer patients by testing as to whether circulating tumor cells are presented after collecting one-tube of blood from cancer patient, in which the metastatic cancer cannot be detected with the existed image equipment. Especially, according to the present invention, there are advantages that since the method uses a method for amplifying a gene using mRNAs of Ki67 that is a cell division marker and Cytoketatin 19 that is an epithelial antigen, it can detect the unseeable amount, and since it does not use Antigen-Antibody reaction, it is very cheap method. Additionally, it could be found that the present invention had high specificity as compared with the existed known RT-PCR method, and also the result could be more easily confirmed because the step for confirming the band using an electrophoresis was not required.
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0061] FIG. 1 is a diagram showing as to whether Cytokeratin 19 is expressed per cell lines, in which A; MCF7, B; SKBR3, C; MDA-MB 231, D; A549, E; HeLa, F: SKOV3, G; THP-1, and H; Blank Control.
[0062] FIG. 2 is a diagram showing as to whether Ki67 is expressed per cell lines, in which A; MCF7, B; SKBR3, C; MDA-MB 231, D; A549, E; HeLa, F: SKOV3, G; THP-1, and H; Blank Control.
[0063] FIG. 3 is a diagram showing the detection of Cytokeratin in a metastatic breast cancer patient, in which Red Quadrangle; Standard Curve (Blood+MCF7 10 5 -1), and Blue Quadrangle; Patient Group.
[0064] FIG. 4 is a diagram showing the confirmation of sensitivity and specificity of RT-PCR method to cytokeratin 19 . MCF7 that is a breast cancer-cell was diluted from 10 5 to 1 cell by stages with 10 ml of healthy person's blood, and then the experiment was performed. As a result, it could be detected to one cell. In addition, as a result for confirming the expression aspect in each cancer-cell line, it could be found that the cell was not detected in a monocyte and the band of Cytokeratin 19 could be confirmed in each cancer-cell line. {circle around (1)} THP-1 (Monocyte), C SKOV3 (Ovarian cancer-Cell line) {circle around (3)} HeLa (Cervical cancer-Cell line) {circle around (4)}˜{circle around (6)} Breast cancer-Cell line (MDA-MB 231, MCF7, SKBR3) {circle around (7)} Blank control. Additionally, in the case of Patient Group (P1-P6), the band of Cytokeratin 19 was confirmed in all of 6 clinical specimens and also the band was confirmed in one group of the normal (N1-N4).
[0065] FIG. 5 is a diagram showing Primer positions of the existed method and the present invention, in which Red color indicates the position of primer used for the existed method ( 516 - 675 ), Blue color indicates the position of primer used for the present invention ( 1012 - 1107 ), and Green color indicates the position of probe used for the present invention ( 1037 - 1059 ).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0066] Hereinafter, the present invention will be described in more detail through the non-limited Examples. However, Examples are only for illustrating the present invention and the range of the present invention is not limited to Example.
Example 1
Isolation of Cell from Patient's Blood
[0067] The blood was collected to EDTA tube from the vein of cancer patient. 5 ml of the blood that was first collected was discarded in order to prevent a contamination from an epithelial cell, and then 10 ml of the blood that was lately collected was used for the test method. An erythrocyte lysis process that was a first process should be started within 4 hours after collecting the blood in order to prevent mRNA damage from the patient's blood. In order to lysis an erythrocyte from the blood, 5 times volume of the erythrocyte lysis solution containing 154 mM of NH 4 Cl, 9 mM of KHCO 3 , and 0.1 mM of EDTA was added, vortexed, maintained for 10 minutes at room temperature, centrifuged at 400 g and 4° C., and then the supernatant was carefully discarded. In order to remove extra erythrocyte, 10 ml of RBC lysis buffer was added; maintained for 5 minutes in an ice; again centrifuged at 3000 rpm and 4° C. for 2 minutes; the supernatant was carefully discarded; 1 ml of PBS was added; the pellet was again floated; and then RNase A (100 ug/ml) was treated for 5 minutes in order to remove a free nucleic acid that was presented in the blood.
Example 2
Total RNA Isolation from Isolated Cell
[0068] The pellet that was again floated was centrifuged at 3000 rpm and 4° C. for 2 minutes; the supernatant was removed with pipetting; then 1 ml of Trizol reagent (Invitrogen) was added and then Total RNA was isolated according to the protocol of the manufacturing firm.
Example 3
cDNA Production from Isolated Total RNA and Real-Time PCR Performance
[0069] 1) cDNA Synthesis
[0070] cDNA was synthesized by adding 2 ug of the isolated total RNA, 0.25 ug of random primer (Invitrogen), 250 uM of dNTP (Cosmo gene tech), 50 mM of Tris-HCl (pH 8.3), 75 mM of KCl, 3 mM of MgCl 2 , 8 mM of DTT, and 200 units of MMLV reverse transcriptase polymerase (Invitrogen), adding DW treated with DEPC to be 20 ul of the final volume, mixing, and then reacting the synthesizing reaction solution at 25° C. for 10 minutes, at 37° C. for 50 minutes, and then at 70° C. for 15 minutes in a thermocycler (ABI).
[0071] 2) Real-Time PCR Performance
[0072] For the reactant composition of Real-Time PCR, 25 mM of TAPS (pH 9.3, 25° C.), 50 mM of KCl, 2 mM of MgCl 2 , 1 mM of 2-mercaptoethanol, 200 μM of each dNTP, 1 unit of Tag polymerase (TAKARA), 1 pmole of Forward primer, 1 pmole of Reverse primer, 1 pmole of probe, and 2 ul of synthesized cDNA were added to be 20 ul of the finial volume and then perform.
[0073] Each of primers and probes were as follows:
[0000]
Primer and Probe for Cytokeratin 19 (Amplified
Fragment 96 bp)
Forward:
(Sequence No. 1)
5′GATGAGCAGGTCCGAGGTTA-3′
Reverse:
(Sequence No. 2)
5′TCTTCCAAGGCAGCTTTCAT-3′
Probe:
(Sequence No. 3)
5′FAM-CTGCGGCGCACCCTTCAGGGTCT-BHQ1-3′
Primer and Probe for Ki67
Forward:
(Sequence No. 4)
5′TAATGAGAGTGAGGGAATACCTTTG-3
Reverse:
(Sequence No. 5)
5′AGGCAAGTTTTCATCAAATAGTTCA-3
Probe:
(Sequence No. 6)
5′FAM-GGCGTGTGTCCTTTGGTGGGCA-BHQ1-3
Primer and Probe for TBP
Forward:
(Sequence No. 7)
5′CACAGTGAATCTTGGTTGTAAACTTGA-3
Reverse:
(Sequence No. 8)
5′AAACCGCTTGGGATTATATTC G-3
Probe:
(Sequence No. 9)
5′FAM-AAGACCAATGCACTTCGTGCCCGA-BHQ1-3
[0074] PCR reaction was performed using ABI 7500Fast (Applied Biosystem) as follows: performing one time at a denaturation temperature, 94° C. for 5 minutes; and then performing 40 times the cycle of a denaturation temperature, 95° C. for 30 seconds and an annealing temperature, 55° C. for 20 seconds, repeatedly. In addition, the fluorescence measurement steps were added after each of the annealing processes to measure the fluorescent value that was increased per each of cycles.
Example 4
Result Analysis
[0075] Each of experiment results was analyzed using 7500 Software v2.0.4 (Applied Biosystem). In the case of Cytokeratin 19, MCF7 that was a breast cancer-cell was diluted by stages using 10 ml of normal blood from 10 5 to 1 cell and then drawn the relative quantitative curve so that the amount of relative circulating tumor cell could be measured using Ct value. In the case of Ki67, Ki67 expression amount was compared and quantitatively weighed based on the expression amount of Ki67 expressed in the normal blood for checking the expression rate. At this point, each of Ki67 expression amounts was compared based on the expression amount of TBP that was a house keeping gene.
[0076] While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.
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There is provided a method for providing information for diagnosing cancer using Real-Time RT-PCR, and a kit for diagnosing cancer for the method.
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FIELD OF THE INVENTION
[0001] This invention relates generally to the field of telecommunication data management. Specifically to Session Initiation Protocol (SIP) networks and enabled devices. More specifically to secure communications over SIP networks and enabled devices.
BACKGROUND OF THE INVENTION
[0002] In traditional circuit-switched networks, such as the Public Switched Telephony Network (“PSTN”), each user endpoint is connected to at most one switching system. In a business enterprise, a business telephone is connected to a single Private Branch Exchange (“PBX”). A PBX is an intelligent switching point within a circuit-switched network that is responsible for routing calls to a plurality of internal nodes or public destinations via a single PSTN switching system.
[0003] Newer telephony networks that employ packet-switching technologies are growing in popularity. In particular, packet-switched telephony networks that use the Internet Protocol (IP) as a network protocol for transmitting and receiving voice data are becoming more prevalent. These so-called Internet Telephony (IT) networks have the potential to offer new features and services that are currently unavailable to subscribers of circuit-switched telephony networks. Conceptually, IT Networks differ from the PSTN systems in that they generally transmit voice data exchanged between two subscriber endpoints, according to an IP format. More specifically, they encapsulate voice data into data packets, which are transmitted according to an IP format in a similar manner as textual data is transmitted from one computer to another via the internet.
[0004] The Session Initiation Protocol (SIP) is one of several protocols that may be used with the Internet Protocol to support Internet Telephony applications. The SIP specification is defined in the Internet Engineering Task Force (IETF) Request for Comments (RFC) 3261, dated June 2002; the disclosure of which is incorporated herein by reference in its entirety. SIP is an application-layer control protocol for creating, modifying, and terminating sessions between networked endpoints, which are referred to as SIP Enabled Devices, User Agents or simply SIP endpoints.
[0005] As discussed above, SIP Enabled Devices implement a network communication protocol, wherein a communication session is established for two endpoints to transmit and receive data. As such, each SIP Device in a SIP network is assigned a unique SIP address or terminal name, which is defined in a SIP Universal Resource Identifier (URI). The format of a SIP URI is similar to that of an email address, which typically includes a user name “@” a domain name, for example “sip:alice@siemens.com.” SIP URI data is placed into header fields of SIP messages, for example to identify a sender and a receiver of the SIP message. For secure communications, the SIP Specification also defines a SIPS URI, for example “sips:alice@siemens.com.” Accordingly, when a SIPS URI is used the SIP Enabled Device associated with the SIP URI may implement an encryption protocol for transmitting data in a secure communication session. It should be noted that the SIPS URI protocol may be used in the same way as the SIP URI
[0006] The mechanism to establish secure voice over IP communication calls involves exchange of components of the security keys that are used for media encryption. The more secure key management solutions involve establishment of the keys using a key negotiation technique wherein each end of the call provides one half of the component of the key (this method is commonly known as dynamic key exchange (DKE) and employed in key management protocols such as MIKEY option 3 or SDescription).
[0007] These mechanisms require high amount of processing capacity for the originating device if a call is forked (multiple recipients are called) since the originating party must negotiate the key independently with each called device. As such these mechanisms work well for one-to-one call scenarios but not for one-to-many call scenarios like parallel ringing, pickup groups, multiple line appearances, etc. In forking scenarios the call is presented to many parties and the first one to answer determines where the call media will be established. Since SIP phones have limited processing power and SIP servers (B2BUA) do not expose multiple dialogs towards the originator these mechanisms cannot be implemented.
[0008] Therefore, it is desirable to have a system that allows a caller to initiate a secure call to multiple users over a SIP network.
SUMMARY OF THE INVENTION
[0009] These and other drawbacks in the prior art are overcome in large part by a system and method according to embodiments of the present invention.
[0010] In some embodiments, a call forking dynamic key exchange system may include one or more of the following features: (a) a memory comprising, (i) a dynamic key exchange program that allows a caller to initiate a call having a security request to multiple subscribers and selecting at least one subscriber who answers the call, and (b) a processor coupled to the memory that executes the dynamic key exchange program.
[0011] In some embodiments, a method for securing multiple-call telecommunications may include one or more of the following steps: (a) placing a call with a first half of a security key to multiple subscribers, (b) receiving a response from at least one answering subscriber, (c) terminating the call to all non-answering subscribers, (d) receiving a second half component of a security key from the one subscriber, (e) determining if the one subscriber has answered, (f) detecting an indicator to begin secure communications, (g) initiating secure media communication.
[0012] In some embodiments, a machine readable medium comprising machine executable instructions may include one or more of the following features: (a) call instructions that route a call to multiple subscribers, (b) termination instructions that terminate the call to all non-answering subscribers, (c) secure instructions that initiate secure media communications based upon an answering subscriber's security key, and (d) detect instructions that detect when the unsecured speech path has been created.
[0013] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not necessarily restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which:
[0015] FIG. 1 shows a block diagram of software modules and hardware components implemented in a SIP Enabled Device in an embodiment of the present invention;
[0016] FIG. 2 shows a diagram of a user interface of a SIP Enabled Device in an embodiment of the present invention;
[0017] FIG. 3 shows an exemplary network of SIP Enabled Devices connected to a network for use in a SIP Enabled Internet Telephony application in an embodiment of the present invention;
[0018] FIG. 4 shows a diagram of a communication session message exchange between two SIP Enabled Devices in an embodiment of the present invention;
[0019] FIG. 5 shows a call flow for a secure user to user communication;
[0020] FIG. 6 shows a call flow for a secure user to multiple users call implementation in an embodiment of the present invention;
[0021] FIG. 7 shows a flow chart for a dynamic key exchange for call forking program in an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The following discussion is presented to enable a person skilled in the art to make and use the present teachings. Various modifications to the illustrated embodiments will be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments and applications without departing from the present teachings. Thus, the present teachings are not intended to be limited to embodiments shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like elements in different figures have like reference numerals. The figures, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the present teachings. Skilled artisans will recognize the examples provided herein have many useful alternatives and fall within the scope of the present teachings.
[0023] Generally, under the present invention, a SIP Enabled Device is a hardware device implementing an SIP Enabled Application module that facilitates communication sessions based on the SIP Internet Telephony communication protocol. Examples of SIP Enabled Devices include telephones, personal computers, and multimedia conferencing systems or any other type of device capable of implementing the SIP communication protocol.
[0024] Embodiments of the present invention disclose a mechanism that enables implementation of dynamic key exchange for media encryption in call forking scenarios that cannot otherwise be implemented within limited SIP devices (SIP UA (user agent) and SIP servers (B2BUA (back-to-back user agent))) processing power. An embodiment of the present invention proposes a solution that can be implemented by delaying the second half of the key exchange after call establishment. A mechanism, wherein an end-to-end call can be established employing a more secure key negotiation mechanism with half key negotiation techniques and still work for one-to-many (forking) call scenarios is employed.
[0025] Referring to FIG. 1 , an SIP Enabled Device 100 is comprised of a User Interface Control Logic module 101 that interfaces with a user interface (an exemplary user interface is shown in FIG. 2 and discussed below). The User Interface Control Logic module 101 also interfaces with an SIP Enabled Application 104 . SIP Enabled Application 104 implements a controller coordinating the various modules interacting within a single SIP Enabled Device 100 to send and receive SIP messages (as shown in FIG. 4 and discussed below). SIP Enabled Application 104 is also responsible for processing data from SIP communication messages and controlling additional functionality associated with SIP Enabled Device 100 . SIP Enabled Application module 104 and the Network Communication Logic module 106 are modules that are stored on SIP enabled device 100 in memory 120 and executed by processor 125 .
[0026] Further, the SIP Enabled Application 104 also interfaces with Network Communications Logic module 106 to send and receive non-SIP messages (not shown). Network Communications Logic module 106 implements data management and communications protocols for communicating with other network resources. Network Communications Logic module 106 interfaces with Network Interface 107 , which is used to physically interface to a network (an exemplary network is shown in FIG. 3 and discussed below) that provides connectivity with other networked devices.
[0027] FIG. 2 shows an example of a User Interface 200 for an SIP Enabled Device used for Internet telephony applications. User Interface 200 is comprised of components including: handset mouthpiece 201 , handset earpiece 202 , handset switch 203 , text display 204 , ringer 205 , and keypad 206 , as well as user input button 207 and an LED indicator 208 . A user physically manipulates the User Interface 200 components to operate the SIP Enabled Device 200 in a manner that is similar to a telephone.
[0028] SIP Enabled Device 200 may display data extracted from a SIP URI corresponding to the specific SIP Enabled Device. More specifically, one aspect of the SIP Enabled Device's SIP Enabled Application 104 is to maintain current date and/or time information 214 and display the data on text display 204 . Also, SIP Enabled Application 104 may be configured to extract Host Address and/or User Information 215 —data routing information, such as “561-55X-1234” and “x1234” (Terminal Number and Terminal Name) data from the SIP URI (a listing of SIP Enabled device data specific to a terminal that is used to facilitate data transmissions) for the SIP endpoint.
[0029] FIG. 3 depicts an SIP Enabled Device network diagram illustrating exemplary devices that may be connected in a SIP network. In this example, subscriber A's SIP Enabled Device 300 is connected to a Local Area Network (LAN) 301 . LAN 301 , in turn, is connected to Network Server 302 , which is also connected to Wide Area Network 303 . Wide Area Network 303 is also connected to Network Server 304 , wherein the Network Server 304 is connected to LAN 305 , which is also connected to subscriber B's SIP Enabled Device 306 . For illustrative simplicity, Network Servers 302 and 304 each perform the function of a SIP Proxy Server, a SIP Redirect Server, and a SIP Registrar; the functionality of which are defined in the SIP protocol specification. These Network Servers also contain additional functionality that is required for the SIP Enabled Devices to communicate; for example a Domain Name System (DNS) server, a Dynamic Host Control Protocol (DHCP) server, and a Lightweight Directory Access Protocol (LDAP) server.
[0030] FIG. 4 illustrates a generic exchange of data messages during SIP communication session creation. The SIP session shown results from subscriber A's SIP Enabled Device 400 initiating a voice call to subscriber B's SIP Enabled Device 420 . For illustrative simplicity, only the SIP Enabled Application ( 401 / 411 ) for each SIP Enabled Device is shown. Prior to placing the voice call, subscriber A has configured the SIP Enabled Device 400 with a SIP address of “561-55x-1234” 403 (host address data from the SIP URI) and subscriber B has configured the SIP Enabled Device 420 with a SIP address of “561-55x-1235” 413 .
[0031] During the SIP communication session, each SIP Enabled Application ( 401 / 411 ) uses these SIP addresses ( 403 , 413 ) for routing data transmissions, and thereby establish and maintain a communication session. This is achieved by the respective SIP Enabled Applications interacting with a User Interface on the SIP Enabled Device to sample, encapsulate voice data for transmission on one SIP Enabled Device, while processing transmitted data packets and synthesizing the corresponding voice data on the other SIP Enabled Device. With regard to data transmission, subscriber A's SIP Enabled Application 401 communicates with subscriber B's SIP Enabled Application 411 by inserting the address (561-55x-1235) 413 into the SIP Communication Request (Comm. Request) message 410 . Accordingly, in response subscriber B's SIP Enabled Application 411 prepares a Communication Request Acknowledgement response message 415 (The message exchange between the SIP Enabled Devices 400 and 420 has been modified for the purposes of illustration and simplification, for a more detailed description of the actual SIP communication protocol refer to RFC 3261.)
[0032] With reference to FIG. 5 , a call flow for a secure user to user communication is shown. To initiate a secure SIP session with traditional DKE subscriber A 400 would pick up the phone and call the entity (s)he desired to have a secure phone conversation with. This would initiate a security request containing the first half of a secure key. Telephony server 450 would then route this request to the desired entity, in this case subscriber B 420 . To accept the call, the security answer would be sent back. The security answer contains the other half of the secure key. Telephony server 450 would then route this answer back to subscriber A where it would be determined if the second half of the key was valid and if so a secure phone conversation could take place. Such a protocol can be found in the Internet Engineering Task Force (IETF) Request for Comments (RFC) 3830, dated August 2004. However, this form of DKE requires high processing power for the originating device when a call is forked since the originating party must negotiate the key independently with each called device. As such this form of DKE works well for one-to-one call scenarios but not for one-to-many call scenarios.
[0033] With reference to FIGS. 6 & 7 , a call flow for a secure user to multiple users call implementation in an embodiment of the present invention is shown. DKE for call forking system 700 begins when subscriber 600 initiates a call to multiple subscribers at state 702 . This causes a request call to go out with a first half of the security key attached 606 . Telephony server 602 then relays this message to subscribers 604 A and 604 B at 608 . A first half of the security key is passed along to all forked destinations but the destinations are instructed not to respond with the second half of the key until the call has been answered and subsequently a period of silence is detected enabling the answering destination to send the second half of the key. System 700 then determines if any subscriber has answered at state 704 . If no subscriber has answered, system 700 routes back to state 704 to inquire again. If a subscriber answers, system 700 proceeds to state 706 where a response with delayed security is sent to telephony server 602 at 610 . Response 610 from the answering party indicates to phone 600 that security is pending. Typically securing a phone call can occur very quickly and therefore user interface 600 may not require this information. However, if the call were a data call, e.g., fax, the calling party could delay sending information and have some quiet time so security could be negotiated prior to sending data. Telephony server 602 then relays this message to subscriber 600 at 612 . At state 708 all calls to non-answering subscribers is terminated 614 .
[0034] An unsecured speech path 616 has now been created. System 700 then determines at state 710 if silence can be detected 618 on unsecured speech path 616 . It is contemplated that any method of determining when a secure media can be established is fully contemplated, such as putting the caller and subscriber on hold, without departing from the spirit of the invention. If silence is not detected, then system 700 routes back and continues to ask the question at state 710 . If silence is detected, then system 700 can proceed to state 712 where the second half of the security key is provided by subscriber 604 B at 620 . Server 602 then relays the second half of the security key to caller 600 at 622 . Once again, if the second half of the security key is valid, then secure media 624 can be established at state 714 .
[0035] It is believed that the present invention and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof, it is the intention of the following claims to encompass and include such changes.
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In some embodiments, a call forking dynamic key exchange system may include one or more of the following features: (a) a memory comprising, (i) a dynamic key exchange program that allows a caller to initiate a call having a security request to multiple subscribers and selecting at least one subscriber who answers the call, and (b) a processor coupled to the memory that executes the dynamic key exchange program.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present U.S. patent application claims a priority under the Paris Convention of Japanese patent application No. 2006-24507 filed on Feb. 1, 2006, and shall be a basis of correction of an incorrect translation.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a biometric authentication apparatus, a biometric authentication system, and a biometric data management method.
[0004] 2. Description of Related Art
[0005] In recent years, authentication using biometric data of a person such as a fingerprint, a vein, an iris, a retina, a hand shape, a facial configuration, a somatotype, a voice print or the like for security protection has been widely recognized. Accordingly, techniques relative to the improvement of authentication accuracy and the improvement of an authentication speed have been proposed (for example, refer to JP-2003-186847A and JP-2001-344605A). Because authentication based on biometric data has no problems of loss unlike authentication by a possession such as an ID card or the like, the biometric data authentication has high convenience. Further, because the biometric data authentication has a feature of the difficulty of masquerade, the application of the biometric data authentication to various fields is being promoted. For example, an image formation apparatus such as a copier, a multi-function printer (MFP) or the like, having a biometric authentication function has been studied.
[0006] By the way, because registration and deletion of verification data described above is generally performed by an administrator of an authentication apparatus or an authentication system using an exclusive management tool, a user himself or herself cannot perform an additional registration of biometric data for verification (hereinafter it may be referred to as verification data) nor deletion of unnecessary verification data, and consequently such a system lacks convenience.
[0007] Furthermore, in the techniques disclosed in JP-2003-186847A and JP-2001-344605A, because management of verification data is performed by an administrator, the techniques cannot solve the problem mentioned above.
SUMMARY
[0008] The present invention has been made to solve the above problems. An object of the invention is to provide a biometric authentication apparatus, a biometric authentication system or a biometric data management method, capable of increase in the level of convenience in the management of verification data.
[0009] In order to achieve the above object, according to one embodiment reflecting a first aspect of the present invention, the biometric authentication apparatus, comprises: an operation unit receiving an instruction from a user; a biometric reading unit reading biometric data; a verification data storage unit storing a plurality of pieces of verification data for verifying against the biometric data; a control unit verifying the biometric data read by the biometric reading unit against the verification data and storing the biometric data as the verification data into the verification data storage unit based on the instruction input through the operation unit; and an information unit informing of a verification result by the control unit, wherein the control unit verifies the biometric data against the verification data before the storage of the biometric data, and when the verification result indicates a disagreement, the control unit stores the biometric data into the verification data storage unit.
[0010] According to another embodiment reflecting a second aspect of the present invention, the biometric authentication apparatus, comprises: an operation unit receiving an instruction from a user; a biometric reading unit reading biometric data; a verification data storage unit storing a plurality of pieces of verification data for verifying against the biometric data; a control unit verifying the biometric data read by the biometric reading unit against the verification data and storing the biometric data as the verification data into the verification data storage unit based on the instruction input through the operation unit; and an information unit informing of a verification result by the control unit, wherein the information unit gives a notice of urging ascertainment of whether to store the biometric data into the verification data storage unit when a verification result by the control unit indicates a disagreement, and the control unit stores the biometric data into the verification data storage unit when an instruction allowing the storage of the biometric data into the verification data storage unit is input through the operation unit.
[0011] Preferably, the information unit informs of a result of the storage of the biometric data by the control unit.
[0012] Preferably, the biometric authentication apparatus further comprises a user management information storage unit storing user management information including identification information for identifying the user and/or personal identification number peculiar to the user, wherein the control unit stores the biometric data into the verification data storage unit when the user management information input through the operation unit agrees with the user management information stored in the user management information storage unit.
[0013] Preferably, when an instruction instructing deletion of specific verification data among the plurality of pieces of verification data stored in the verification data storage unit is input, the control unit deletes the specified verification data from the verification data storage unit.
[0014] Preferably, the biometric authentication apparatus further comprises a user management information storage unit storing user management information including identification information for identifying the user and/or personal identification number peculiar to the user, wherein when the user management information input through the operation unit agrees with the user management information stored in the user management information storage unit, the control unit deletes the specified verification data from the verification data storage unit.
[0015] The biometric reading unit preferably reads as the biometric data at least one of a fingerprint, a vein, an iris, a retina, a hand shape, a facial configuration, a somatotype and a voice print of the user.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention will become more fully understood from the detailed description given hereinafter and the accompanying drawings which are given by way of illustration only, and thus are not intended as a definition of the limits of the scope of the invention, and wherein:
[0017] FIG. 1 is a view showing the configuration of a biometric authentication system;
[0018] FIG. 2 is a view showing the internal configuration of an image formation apparatus 1 to which a biometric authentication apparatus of the present invention is applied;
[0019] FIG. 3 is a view showing an example of a priority order table stored in a storage unit;
[0020] FIG. 4 is a view showing the internal configuration of a biometric data server;
[0021] FIG. 5 is a view showing the procedure of verification data registration processing;
[0022] FIG. 6 is a view showing the procedure of duplication ascertainment processing in the verification data registration processing in FIG. 5 ;
[0023] FIG. 7 is a view showing the procedure of registration processing in the duplication ascertainment processing in FIG. 6 ;
[0024] FIG. 8 is a view showing the procedure of verification data deletion processing;
[0025] FIG. 9 is a view showing the procedure of biometric authentication processing;
[0026] FIG. 10 is a view showing the procedure of deletion processing in the biometric authentication processing in FIG. 9 ; and
[0027] FIG. 11 is a view showing the procedure of registration processing in the biometric authentication processing in FIG. 9 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] An embodiment relating to the biometric authentication apparatus, the biometric authentication system, and the biometric data management method of the present invention will be described with reference to the attached drawings.
<First Embodiment>
[0029] First, the configuration of a biometric authentication system 100 according to the embodiment is described with reference to FIGS. 1-3 .
[0030] FIG. 1 is a view showing the schematic configuration of the biometric authentication system 100 . As shown in FIG. 1 , in the biometric authentication system 100 according to the embodiment, a plurality of image formation apparatuses 1 as biometric authentication apparatuses and a biometric data server 3 are connected to one another in the state capable of mutual communication through a network N such as a local area network (LAN), a wide area network (WAN) or the like. Incidentally, the kind and the number of the equipments connected to the network N are not limited to the example shown in FIG. 1 .
[0031] FIG. 2 is a view showing the internal configuration of each of the image formation apparatus 1 . As shown in FIG. 1 , the image formation apparatus 1 is composed of a control unit 10 , an operation unit 11 , a display unit 12 , a biometric reading unit 13 , a storage unit 14 , an image reading unit 15 , a printing paper housing and conveying unit 16 , an image formation unit 17 , a communication unit 18 , an I/F unit 19 and the like. Each unit is connected with each other through a bus 20 .
[0032] The control unit 10 is composed of a central processing unit (CPU) which is not shown, a random access memory (RAM) and the like. The CPU executes various kinds of processing by using a predetermined region of the RAM as a working area in cooperation with the various control programs previously stored in the storage unit 14 , and wholly controls the operation of each unit constituting the image formation apparatus 1 .
[0033] Specifically, the control unit 10 periodically or any time obtains (downloads) verification data 331 stored in a storage unit 33 of the biometric data server 3 together with the data ID corresponding to the verification data 331 through the network N, and stores the verification data 331 into the storage unit 14 as verification data 141 in association with the data ID. Incidentally, also a mode in which the difference between the verification data 331 and the existing verification data 141 stored in the storage unit 14 is detected at the time of performing the obtainment of the verification data 331 and only the difference value is obtained or is reflected on the verification data 141 , may be adopted.
[0034] At the time of using the image formation apparatus 1 , the control unit 10 performs one-to-N verification of one piece of biometric data read from the biometric reading unit 13 to a plurality (N) of pieces of verification data 141 previously stored in the storage unit 14 in the order based on the priority order registered in a priority order table 142 , and the control unit 10 performs the control to allow the use of the image formation apparatus 1 only when the biometric data agrees with the verification data 141 .
[0035] The control unit 10 stores the biometric data read with the biometric reading unit 13 based on an instruction signal input through the operation unit 11 into the storage unit 14 as verification data, and transmits the verification data to the biometric data server 3 through the network N.
[0036] When an instruction signal instructing deletion of specific verification data among a plurality of pieces of verification data stored in the storage unit 14 is input through the operation unit 11 , the control unit 10 deletes the specified verification data from the storage unit 14 , and transmits the instruction information instructing deletion of the specific verification data to the biometric data server 3 through the network N.
[0037] The control unit 10 makes the storage unit 14 store the image data read by the image reading unit 15 . Further, the control unit 10 controls the printing paper housing and conveying unit 16 and the image formation unit 17 to make them print the image data read by the image reading unit 15 , document data input through the communication unit 18 , or the like on a sheet of printing paper.
[0038] The operation unit 11 is equipped with input keys and the like, and receives information input by an operation of a user as an input signal to output the input signal to the control unit 10 . The display unit 12 is composed of a liquid crystal display (LCD) or the like, and displays various kinds of information based on display signals from the control unit 10 . The display unit 10 may be integrally configured with the operation unit 11 to form a touch panel.
[0039] The biometric reading unit 13 is an apparatus capable of reading at least one kind of biometric data among various kinds of biometric data indicating physical features of a human being such as a fingerprint, a vein, an iris, a retina, a hand shape, a facial configuration, a somatotype, a voiceprint and the like, and is composed of various function units corresponding to biometric data which is an object to be read. The biometric reading unit 13 reads the biometric data of the user of the image formation apparatus 1 under the control by the control unit 10 , and outputs the read biometric data to the control unit 10 .
[0040] The storage unit 14 is equipped with a nonvolatile storage medium made of a magnetic recording medium, an optical recording medium or a semiconductor memory, and stores programs necessary for the operation of the image formation apparatus 1 and the data relative to the execution of the programs.
[0041] Specifically, the storage unit 14 previously stores (or manages) a plurality of pieces of verification data 141 for performing verification to the biometric data read by the biometric reading unit 13 in association with the data IDs. Here, the data IDs mean the identification information capable of uniquely identifying each user (verification data) such as the employee numbers of the users, and the verification data is managed based on the data IDs. Moreover, the storage unit 14 stores the priority order table 142 indicating the relations between the priority orders registered beforehand through the operation unit 11 and the verification data.
[0042] FIG. 3 is a view showing an example of the priority order table 142 stored in the storage unit 14 . As shown in FIG. 3 , priority orders (1, 2, 3, 4, 5 . . . 9999, 10000) and the data IDs of the respective pieces of verification data corresponding to the priority orders are set in association with each other. Incidentally, in the embodiment, it is meant that the first rank has the highest priority order, and the priority orders become gradually lower as the value of the rank increases.
[0043] The control unit 10 refers to the data IDs in order based on the priority orders of the data ID priority order table to read the verification data 141 corresponding to each data ID in order, and performs verification to the biometric data of the user read by the biometric reading unit 13 .
[0044] Further, the storage unit 14 previously stores user management information 143 for identifying each user using the image formation apparatus 1 . Here, the user management information indicates the information for managing the users of the image formation apparatus 1 , and includes the identification information for identifying each user and/or the personal identification number peculiar to each user. Incidentally, in the embodiment, it is supposed that employee numbers of the users are used as the identification information and the employee numbers are regarded as the information corresponding to the data IDs described above.
[0045] When the control unit 10 is instructed by a user to register new verification data or to delete specific verification data, the control unit 10 urges the user to input user management information peculiar to the user. The control unit 10 performs registration of the new verification data or deletion of the specific verification data only when the user management information input by the user and the user management information 143 stored in the storage unit 14 agree with each other. That is, the user management information is an authentication key relative to the management of the verification data 141 .
[0046] In FIG. 2 , the image reading unit 15 includes a light source radiating light onto a manuscript, an image sensor such as a charge coupled device (CCD) image sensor, a complementary metal-oxide semiconductor (CMOS) image sensor or the like, which photoelectrically converts the light reflected from the manuscript, a scanning unit scanning the light to be radiated to the manuscript, an image processing unit performing various kinds of conversions and processing of an electric signal read by the image sensor to output image data, and the like, which are not shown. Under control by the control unit 10 , the image reading unit 15 reads an image recorded in the manuscript, and generates image data to output the generated image data to the control unit 10 .
[0047] The printing paper housing and conveying unit 16 includes a printing paper housing unit housing printing paper therein, a printing paper existence detection unit detecting whether printing paper is housed in the printing paper housing unit or not, a size detection unit detecting the paper size of the printing paper housed in the printing paper housing unit, a conveyance unit conveying the printing paper housed in the printing paper housing unit, and the like, all not shown. Under control by the control unit 10 , the printing paper housing and conveying unit 16 conveys the printing paper with the paper size depending on image data or instructed through the operation unit 11 to the image formation position of the image formation unit 17 , and ejects the printing paper after image formation.
[0048] The image formation unit 17 is a printer of an ink jet type, a laser type, a thermal transfer type, a dot impact type or the like, and forms and records an image on printing paper based on the image data input from the control unit 10 .
[0049] The communication unit 18 is a modulator/demodulator (modem), a terminal adapter, a LAN adapter and the like, and performs communication control of various kinds of information given or received between the other equipment (biometric data server 3 ) connected to the network N under control by the control unit 10 .
[0050] The I/F unit 19 is a communication interface which performs data communications with other apparatus, and is configured by, for example, universal serial bus (USB), IEEE 1284, IEEE 1394, PCMCIA or the like. Incidentally, the embodiment adopts a mode to store the verification data 141 and the priority order table 142 into the storage unit 14 . However, when an external storage unit is connected to the I/F unit 19 , a mode to store the verification data 141 and/or the priority order table 142 may be adopted.
[0051] FIG. 4 is a view showing the internal configuration of the biometric data server 3 . As shown in FIG. 4 , the biometric data server 3 is composed of a control unit 30 , an operation unit 31 , a display unit 32 , the storage unit 33 , a communication unit 34 and the like, and each unit is connected with one another through a bus 35 .
[0052] The control unit 30 is composed of a CPU which is not shown, an RAM and the like, and the CPU executes various kinds of processing using a predetermined region of the RAM as a working area in cooperation with various control programs stored in the storage unit 33 beforehand to wholly control the operation of each unit constituting the image formation apparatus 1 .
[0053] Specifically, the control unit 30 controls the storage unit 33 so that an image formation apparatus 1 connected through the network N is able to obtain (download) the verification data 331 stored in the storage unit 33 , and supplies the verification data 331 in response to an obtainment request from the image formation apparatus 1 .
[0054] Moreover, when the control unit 30 receives verification data transmitted from the image formation apparatus 1 , the control unit 30 stores (i.e., registers) the verification data into the storage unit 33 . Moreover, when the control unit 30 receives instruction information instructing deletion of specific verification data transmitted from the image formation apparatus 1 , the control unit 30 deletes the verification data specified based on the instruction information from the storage unit 33 .
[0055] The operation unit 31 is equipped with the input keys and the like, and receives information input by an operation of the user as an input signal to output the input signal to the control unit 30 . The display unit 32 is composed of a liquid crystal display (LCD) or the like, and displays various kinds of information based on a display signal from the control unit 30 . Moreover, a mode in which the display unit 32 integrally constitutes a touch panel together with the operation unit 31 may be adopted.
[0056] The storage unit 33 is equipped with a nonvolatile storage medium composed of a magnetic recording medium, an optical recording medium or a semiconductor memory, and stores the programs necessary for the operation of the biometric data server 3 and the data relative to the execution of the programs.
[0057] Moreover, the storage unit 33 includes a data management region such as a data base in the storage region of the storage unit 33 , and the storage unit 33 stores the verification data 331 to be used by each of the image formation apparatus 1 in association with the data IDs in the data management region to manage the verification data 331 .
[0058] The communication unit 34 is a modem, a terminal adapter, a LAN adapter and the like, and performs communication control of various kinds of information given and received between the other equipment (image formation apparatus 1 ) connected to the network N under control by the control unit 30 .
[0059] In the following, with reference to FIG. 5 , the operation of the biometric authentication system 100 according to the embodiment is described.
[0060] FIG. 5 is a view showing the procedure of verification data registration processing of the image formation apparatus 1 according to the embodiment. Incidentally, each piece of processing in FIG. 5 shows the processing executed by the control unit 10 in cooperation with a predetermined program stored in the storage unit 14 .
[0061] First, when an instruction signal instructing registration of verification data is input through the operation unit 11 (Step S 11 ; Yes), the procedure stands by until a detection signal of a user is input from the biometric reading unit 13 (Step S 12 ; No). When the input of the detection signal is ascertained (Step S 12 ; Yes), the procedure moves to the duplication ascertainment processing (Step S 13 ). In the following, the duplication ascertainment processing at Step S 13 is described with reference to FIG. 6 .
[0062] FIG. 6 is a view showing a procedure of the duplication ascertainment processing.
[0063] First, when the biometric data read by the biometric reading unit 13 is obtained (input) (Step S 14 ), a pointer P specifying the priority order at the time of reading the verification data based on the data IDs of the priority order table 142 is set at the first rank (P=1) (Step S 15 ).
[0064] Successively, a data ID corresponding to the present pointer P is specified from the priority order table 142 (Step S 16 ), and the verification data 141 stored in association with the data ID is read from the storage unit 14 (Step S 17 ). The read verification data 141 is verified against the biometric data obtained at Step S 14 (Step S 18 ), and it is judged whether both the data agree with each other or not (Step S 19 ).
[0065] When it is judged that the verification data 141 and the biometric data agree with each other at Step S 19 (Step S 19 ; Yes), the information indicating agreement of the biometric data and the verification data 141 (for example, the character information such as “already registered” or the like) is displayed on the display 12 , and thereby the fact is informed to the user (Step S 20 ). Thereafter the procedure moves to Step S 33 in FIG. 5 .
[0066] On the other hand, when it is judged that the verification data 141 and the biometric data do not agree with each other at Step S 19 (Step S 19 ; No), it is judged whether all pieces of verification data 141 stored in the storage unit 14 have been verified against the biometric data or not (Step S 21 ). Here, when it is judged that there is non-verified verification data 141 (Step S 21 ; No), the priority order is lowered by one rank by the execution of the increment of the pointer P by one (P=P+1) (Step S 22 ). Thereafter, the procedure returns to Step S 16 again.
[0067] On the other hand, when it is judged that all pieces of verification data 141 have been verified against the biometric data (Step S 21 ; Yes), the procedure moves to registration processing (Step S 23 ). In the following, with reference to FIG. 7 , the registration processing at Step S 23 is described.
[0068] FIG. 7 is a view showing the procedure of a registration processing at Step S 23 .
[0069] First, a screen urging the user to input the user management information of the user of the present image formation apparatus 1 is displayed on the display unit 12 (Step S 24 ), and the procedure stands by until the input of the user management information through the operation unit 11 (Step S 25 ; No).
[0070] Here, when it is judged that the user management information has been input (Step S 25 ; Yes), the user management information and the user management information 143 stored in the storage unit 14 beforehand are verified against each other (Step S 26 ). When it is judged that the verification result indicates disagreement (Step S 27 ; No), the information indicating disagreement of the user management information (for example, the character information such as “The user management information does not agree.” or the like) is displayed on the display unit 12 (Step S 28 ). Thereafter, the present processing, i.e. the duplication ascertainment processing and the verification data registration processing, ends.
[0071] On the other hand, when it is judged that both the user management informations agree with each other (Step S 27 ; Yes), the biometric data obtained at Step S 14 is stored (registered) in the storage unit 14 in association with the data ID (employee number) included in the user management information input at Step S 25 as the verification data (Step S 29 ). Thereby, the data ID corresponding to the new verification data is registered in the priority order table 142 , and a predetermined priority order is set to the data ID. Incidentally, the priority order to be set is not especially limited, and for example, the order of the first rank, which means the highest priority, or of the end rank may be set. When the priority order is specified through the operation unit 11 at the time of inputting the biometric data of the new registration object, the specified priority order may be set.
[0072] Subsequently, it is judged whether the biometric data server 3 is connected to the network N, to which the present image formation apparatus 1 is connected, or not. When it is judged that the biometric data server 3 is not connected to the network N (Step S 30 ; No), the procedure moves to Step S 32 in FIG. 6 .
[0073] On the other hand, when it is judged that the biometric data server 3 is connected to the network N at Step S 30 (Step S 30 ; Yes), the verification data registered at Step S 29 and the data ID corresponding to the verification data are transmitted (uploaded) to the biometric data server 3 through the network N (Step S 31 ), and the procedure moves to Step S 32 in FIG. 6 .
[0074] In the biometric data server 3 which has received the verification data and the data ID transmitted from the image formation apparatus 1 , the verification data and the data ID are stored in the storage unit 33 in association with each other by the control of the control unit 30 , and consequently the registration of the new verification data is performed.
[0075] Returning to FIG. 6 , at Step S 32 , the information indicating completion of the registration of the new verification data (for example, the character information such as “Registration of the verification data has been completed.” or the like) is displayed on the display unit 12 to be informed to the user (Step S 32 ). Thereafter, the procedure moves to Step S 33 in FIG. 5 . According to such a configuration, because the storage (or registration) result is informed to the user, the user can recognize whether the verification data has been registered or not.
[0076] Returning to FIG. 5 , at Step S 33 , the information of ascertaining whether the registration of the verification data is ended or not (for example, the character information such as “Is verification data registration processing ended?” or the like) is displayed on the display unit 12 (Step S 33 ). When the instruction information instructing continuation of the registration of verification data is input through the operation unit 11 based on the display (Step S 34 ; No), the procedure returns to Step S 12 again. On the other hand, when the instruction information indicating ending of the registration of the verification data is input through the operation unit 11 at Step S 34 (Step S 34 ; Yes), the present processing is ended.
[0077] When the biometric data (verification data) which is read by the biometric reading unit 13 and becomes the new registration object is verified against the existing verification data in response to the instruction of the user in this manner and the verification result does not indicate the agreement of them, the verification data of the new registration object is stored (i.e., registered). Thereby, it becomes possible to register the verification data in response to the instruction of the user, and the duplication registration of the verification data with the existing verification data. Consequently, convenience of the management of the verification data can be improved.
[0078] Because the user is authenticated based on the user management information including the identification information for identifying the user and/or the personal identification number peculiar to the user and the storage (registration) of the verification data is performed only when the authentication has been normally performed, the security of the management of the verification data can be improved.
[0079] Further, because a new verification data 141 registered in the image formation apparatus 1 can be registered in the biometric data server 3 as a verification data 331 , it is possible to reflect (or register) the registered new verification data 331 ( 141 ) from the biometric data server 3 to another image formation apparatus 1 .
[0080] Next, verification data deletion processing is described with reference to FIG. 8 .
[0081] FIG. 8 is a view showing the procedure of the verification data deletion processing in the image formation apparatus 1 according to the embodiment. Incidentally, each processing in FIG. 8 shows the processing executed by the control unit 10 in cooperation with a predetermined program stored in the storage unit 14 .
[0082] First, when an instruction signal instructing deletion of verification data is input through the operation unit 11 (Step S 41 ; Yes), a screen urging the user to input user management information for identifying the user of the present image formation apparatus 1 is displayed on the display unit 12 (Step S 42 ), and the procedure stands by until the user management information is input through the operation unit 11 (Step S 43 ; No).
[0083] Here, when it is judged that the user management information has been input (Step S 43 ; Yes), the input user management information is verified against the user management information 143 stored in the storage unit 14 beforehand (Step S 44 ). When it is judged that the verification result does not indicate the agreement of them (Step S 45 ; No), the information indicating disagreement of the user management information (for example, the character information such as “The user management information does not agree.” or the like) is displayed on the display unit 12 to be informed to the user (Step S 46 ). Thereafter, the present processing is ended.
[0084] On the other hand, when it is judged that both the user management informations agree with each other at Step S 45 (Step S 45 ; Yes), a screen urging the user to select the verification data to be the deletion object from the verification data stored in the storage unit 14 (Step S 47 ), and the procedure stands by until specific verification data is specified through the operation unit 11 (Step S 48 ; No).
[0085] Here, when it is judged that the specific verification data has been specified (Step S 48 ; Yes), the specified specific verification data is deleted from the storage unit 14 , and the information related to the data ID associated with the specific verification data is deleted from the priority order table 142 (Step S 49 ).
[0086] Subsequently, it is judged whether the biometric data server 3 is connected to the network N or not. When it is judged that the biometric data server 3 is not connected to the network N (Step S 50 ; No), the procedure moves to Step S 52 .
[0087] On the other hand, when it is judged that the biometric data server 3 is connected to the network N at Step S 50 (Step S 50 ; Yes), the instruction information indicating deletion of the verification data and the data ID corresponding to the verification data which have been deleted at Step S 49 is transmitted to the biometric data server 3 through the network N (Step S 51 ), and the procedure moves to Step S 52 .
[0088] When the biometric data server 3 receives the instruction information instructing deletion of the specific verification data and the data ID transmitted from the image formation apparatus 1 , the biometric data server 3 deletes the instructed verification data and the data ID from the storage unit 33 by the control of the control unit 30 .
[0089] At Step S 52 , the information indicating completion of deletion of the verification data specified by the user (for example, the character information of “The verification data has been deleted.” or the like) is displayed on the display unit 12 to be informed to the user (Step S 52 ). Thereafter, the information ascertaining whether deletion of the verification data is ended or not (for example, the character information such as “Is the verification data deletion processing ended?” or the like) is displayed on the display unit 12 (Step S 53 ).
[0090] Here, when the instruction information instructing continuation of deletion of the verification data is input through the operation unit 11 (Step S 54 ; No), the procedure again returns to Step S 47 . On the other hand, when the instruction information instructing end of deletion of the verification data is input through the operation unit 11 at Step S 54 (Step S 54 ; Yes), the present processing is ended.
[0091] Because it becomes possible to delete verification data in response to an instruction from the user in this manner, the convenience regarding the management of verification data can be improved.
[0092] Further, because a user is authenticated based on the user management information including the identification information for identifying the user and/or the personal identification number peculiar to the user and deletion of the verification data is performed only when the authentication has been normally performed, the security regarding the management of the verification data can be improved.
[0093] Because the verification data 331 corresponding to the verification data which was deleted in the image formation apparatus 1 can be deleted from the biometric data server 3 , it is possible to delete the deleted verification data 331 ( 141 ) from another image formation apparatus 1 through the biometric data server 3 .
[0094] Incidentally, although the biometric data deletion processing according to the embodiment adopts the mode capable of specifying arbitrary verification data to be a deletion object from the verification data stored in the storage unit 14 , the mode is not limited to this one. For example, a mode capable of deleting only the verification data corresponding to the data ID (employee information) of the user management information input from the user may be adopted. Moreover, although the mode of performing the input of the user management information is adopted in the biometric data deletion processing according to the embodiment, the mode is not limited to this one. For example, a mode capable of using the biometric data of a user read from the biometric reading unit 13 as a substitute of the user management information to delete only the verification data agreeing with the biometric data may be adopted.
<Second Embodiment>
[0095] Next, a second embodiment of the present invention is described. For simplification of the description, the same components as those of the first embodiment are denoted by the same reference marks as those of the first embodiment, and the detailed descriptions of them are suitably omitted.
[0096] In the following, with reference to FIG. 9 , the biometric authentication processing of the image formation apparatus 1 according to the embodiment is described.
[0097] FIG. 9 is a view showing the procedure of the biometric authentication processing of the image formation apparatus 1 according to the embodiment.
[0098] First, when the biometric authentication processing is started based on a biometric detection signal input from the biometric reading unit 13 (Step S 61 ; Yes), the biometric data read by the biometric reading unit 13 is obtained (i.e., input) (Step S 62 ).
[0099] Next, the pointer P specifying the priority order when verification data is read based on a data ID of the priority order table 142 is set to the first rank (P=1) (Step S 63 ).
[0100] Successively, the data ID corresponding to the pointer P is specified based on the priority order table 142 (Step S 64 ), and the verification data 141 stored in association with the data ID is read from the storage unit 14 (Step S 65 ). When the read verification data 141 is verified against the biometric data obtained at Step S 62 (Step S 66 ), and it is judged whether both the data agree with each other or not (Step S 67 ).
[0101] When it is judged that the verification data 141 and the biometric data agree with each other at Step S 67 (Step S 67 ; Yes), the information indicating agreement of the biometric data and the verification data 141 (for example, the character information such as “We succeeded in authentication.” or the like) is displayed on the display unit 12 to inform the user of the agreement (Step S 68 ). Thereafter, the information ascertaining whether the agreed verification data is deleted or not (for example, the character information “Is the verification data deleted?” or the like) is displayed on the display unit 12 (Step S 69 ).
[0102] Next, when the contents of the instruction information input by the user through the operation unit 11 is judged and it is judged that the instruction information instructing non-deletion of the verification data has been input (Step S 70 ; No), the processing is immediately ended.
[0103] On the other hand, when it is judged that the instruction information instructing execution of deletion of the agreed verification data has been input at Step S 70 (Step S 70 ; Yes), the procedure moves to deletion processing (Step S 71 ). In the following, the deletion processing at Step S 71 is described with reference to FIG. 10 .
[0104] FIG. 10 is a view showing the procedure of the deletion processing at Step S 71 .
[0105] First, a screen urging the user to input the user management information relative to the user of the present image formation apparatus 1 is displayed on the display unit 12 (Step S 72 ), and the procedure stands by until the user management information is input through the operation unit 11 (Step S 73 ; No).
[0106] Here, when it is judged that the user management information has been input (Step S 73 ; Yes), the user management information is verified against the user management information 143 stored in the storage unit 14 beforehand (Step S 74 ). When it is judged that the verification result does not indicate the agreement of them (Step S 74 ; No), the information indicating disagreement of the user management information (for example, the character information such as “The user management information does not agree.” or the like) is displayed on the display unit 12 to inform the user of the disagreement (Step S 76 ). Thereafter, the present processing and biometric authentication processing is ended.
[0107] On the other hand, when it is judged that both the user management information agree with each other at Step S 75 (Step S 75 ; Yes), the verification data which has agreed at Step S 67 in FIG. 9 is deleted from the storage unit 14 , and the information relative to the data ID associated to the verification data is deleted from the priority order table 142 (Step S 77 ).
[0108] Next, it is judged whether the biometric data server 3 is connected to the network N or not. When it is judged that the biometric data server 3 is not connected to the network N (Step S 78 ; No), the procedure moves to Step S 80 in FIG. 9 .
[0109] On the other hand, when it is judged that the biometric data server 3 is connected to the network N at Step S 78 (Step S 78 ; Yes), the instruction information instructing deletion of the verification data and the data ID corresponding to the verification data which have been deleted at Step S 77 is transmitted to the biometric data server 3 through the network N (Step S 79 ), and the procedure moves to Step S 80 in FIG. 9 .
[0110] When the biometric data server 3 receives the instruction information which has been transmitted from the image formation apparatus 1 and instructs deletion of the specific verification data and the data ID, the biometric data server 3 deletes the instructed verification data and the data ID from the storage unit 33 by the control of the control unit 30 .
[0111] Returning to FIG. 9 , the information indicating completion of the deletion of the verification data (for example, the character information such as “The verification data has been deleted.” or the like) is displayed on the display unit 12 to inform the user of the completion of the deletion (Step S 80 ). Thereafter, the present processing is ended.
[0112] On the other hand, when it is judged that the verification data 141 and the biometric data do not agree with each other at Step S 67 (Step S 67 ; No), it is judged whether all pieces of verification data 141 stored in the storage unit 14 have been verified against the biometric data or not (Step S 81 ). Here, when it is judged that there is non-verified verification data 141 (Step S 81 ; No), the increment of the pointer P by one (P=P+1) is performed, and thereby the priority order is lowered by one rank (Step S 82 ). Thereafter the procedure returns to Step S 64 again.
[0113] On the other hand, when it is judged that all pieces of verification data 141 have been verified against the biometric data at Step S 81 (Step S 81 ; Yes), the information indicating disagreement of the biometric data with the verification data 141 (for example, the character information such as “The verification data has not been registered yet.” or the like) is displayed on the display unit 12 , and the information indicating ascertainment of the registration of new verification data (for example, the character information such as “Is the verification data newly registered?” or the like) is displayed on the display unit 12 (Step S 83 ).
[0114] Next, the contents of the instruction information input through the operation unit 11 by the user are judged. When it is judged that the instruction information instructing not to perform the registration of the new verification data has been input (Step S 84 ; No), the present processing is immediately ended.
[0115] On the other hand, when it is judged that the instruction information instructing to perform the registration of the new verification data has been input at Step S 84 (Step S 84 ; Yes), the procedure moves to the registration processing at Step S 85 . In the following, the registration processing at Step S 85 is described with reference to FIG. 11 .
[0116] FIG. 11 is a view showing a procedure of the registration at Step S 85 .
[0117] First, a screen urging the user to input the user management information relative to the user of the present image formation apparatus 1 is displayed on the display unit 12 (Step S 86 ), and the procedure stands by until the user management information is input through the operation unit 11 (Step S 87 ; No).
[0118] Here, when it is judged that the user management information has been input (Step S 87 ; Yes), the user management information is verified against the user management information 143 stored in the storage unit 14 beforehand (Step S 88 ). When it is judged that the verification result does not indicate the agreement of them (Step S 89 ; No), the information indicating disagreement of the user management information (for example, the character information such as “The user management information does not agree.” or the like) is displayed on the display unit 12 to inform the user of the disagreement (Step S 90 ). Thereafter, the present processing and biometric authentication processing is ended.
[0119] On the other hand, when it is judged that both the user management information agree with each other at Step S 89 (Step S 89 ; Yes), the biometric data input at Step S 62 is stored (registered) into the storage unit 14 as the verification data in association with the data ID (employee number) included in the user management information input at Step S 87 (Step S 91 ). Thereby, the data ID corresponding to the new verification data has been registered in the priority order table 142 , and a predetermined priority order is set to the data ID. Incidentally, the priority order to be set is not especially limited, and for example, the order of the first rank, which means the highest priority, or of the end rank may be set. Moreover, when the priority order has been specified through the operation unit 11 at the time of inputting the biometric data of the new registration object, the specified priority order may be set.
[0120] Next, it is judged whether the biometric data server 3 is connected to the network N or not. When it is judged that the biometric data server 3 is not connected to the network N (Step S 92 ; No), the procedure moves to Step S 94 in FIG. 9 .
[0121] On the other hand, when it is judged that the biometric data server 3 is connected to the network N at Step S 92 (Step S 92 ; Yes), the verification data newly stored at Step S 91 and the data ID corresponding to the verification data are transmitted to the biometric data server 3 through the network N (Step S 93 ), and the procedure moves to Step S 94 in FIG. 9 .
[0122] When the biometric data server 3 receives the verification data and the data ID transmitted from the image formation apparatus 1 , the biometric data server 3 stores the verification data and the data ID into the storage unit 33 in association with each other by the control of the control unit 30 to perform the registration of the new verification data.
[0123] Returning to FIG. 9 , the information indicating completion of the registration of the new verification data (for example, the character information such as “The registration of the verification data has been completed.” or the like) is displayed on the display unit 12 to inform the user of the completion of the registration (Step S 94 ). Thereafter, the present processing is ended.
[0124] As described above, according to the biometric authentication system 100 according to the embodiment, the biometric data (verification data) read by the biometric reading unit 13 is verified against the existing verification data. When the verification result does not indicate the agreement of them, the storage (registration) is performed in accordance with the instruction of the user. Thereby, it becomes possible to register or delete the verification data in response to the instruction of the user, and because the duplication registration with the existing verification data can be prevented, the convenience of the management of the verification data can be improved.
[0125] Moreover, the authentication of the user is performed based on the user management information including the identification information for identifying the user and/or the personal identification number information peculiar to the user, and the storage (registration) or the deletion of the verification data is performed only when the authentication has been normally performed. Consequently, the security of the management of the verification data can be improved.
[0126] The detailed configurations and the detailed operations of the image formation apparatus 1 in the embodiments described above can be suitably modified within the range without departing the sprit of the present invention.
[0127] For example, when the registration or the deletion of verification data is performed, history information of the information indicating the contents of the processing (for example, the addition of the verification data of data ID: 07059, the deletion of the verification data of data ID: 24680, or the like) and the data ID of the user who has instructed the processing, both associated with each other, is recorded in order in the storage unit 14 or the storage unit 33 . Thereby, because it becomes possible for an administrator to ascertain the record later, the convenience of the management of verification data can be improved.
[0128] Further, although the embodiments described above adopt a mode in which the execution of the procedure of each processing is realized by the cooperation of the control unit 10 and the predetermined programs stored in the storage unit 14 , the execution mode is not limited to the one. The mode may be realized by exclusive hardware circuits.
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Disclosed is an information processing device including a biometric authentication apparatus, including: an operation unit receiving an instruction from a user; a biometric reading unit reading biometric data; a verification data storage unit storing a plurality of pieces of verification data for verifying against the biometric data; a control unit verifying the biometric data read by the biometric reading unit against the verification data and storing the biometric data as the verification data into the verification data storage unit based on the instruction input through the operation unit; and an information unit informing of a verification result by the control unit, wherein the control unit verifies the biometric data against the verification data before the storage of the biometric data, and when the verification result indicates a disagreement, the control unit stores the biometric data into the verification data storage unit.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser. No. 12/457,957, filed Jun. 26, 2009, which is an divisional of U.S. application Ser. No. 11/175,281, filed Jul. 7, 2005 and claims priority to Finnish Patent Application No. 20045268 filed on Jul. 7, 2004. The prior applications, including the specifications, drawings and abstracts are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The invention relates to a feeder hopper for a mobile mineral material processing device, a method for locking the walls of the feeder hopper of a mineral material processing device into a working position and a locking means.
BACKGROUND OF THE INVENTION
[0003] Mineral material processing devices are typically used for feeding, conveying, crushing, screening or washing mineral materials. Typically such a processing device comprises a frame and at least one processing unit suitable for processing of mineral materials, for example a feeder, a belt conveyor, a crusher, a screen, or a corresponding device for transferring, refining or sorting mineral material. Often two or several processing units are integrated in the same frame, thus attaining a device suitable for versatile processing of mineral material.
[0004] Often such mineral material processing devices are designed so that they can be transported between different working sites or at least within one working site. Thus, the frame of the mineral material processing device is often provided with runners, wheels or tracks. Mineral material processing devices are often also provided with an independent power source, for example a diesel motor that is connected to wheels or tracks underneath the frame, thus attaining a movable device that is capable of moving independently.
[0005] When a new movable mineral material processing device is designed, the objectives of the design work is in addition to the processing efficiency and productivity that the processing device can be transported and used easily and safely. Sometimes these objectives are contradictory, and the designers must resort to compromises. For example, a high level of productivity requires the use of productive, large-sized processing units in the mineral material processing device. However, the use of such units makes the entire processing device large in size and difficult to transport not only inside the working site, but also between different working sites.
[0006] There are several patent publications known in the world, which disclose inventions with the aim of facilitating the mobility of various kinds of mineral material processing devices. Such publications include for example EP 1 110 625 A2, DE 198 05 378 A1, WO 98/46472 A1, WO 90/08720 WO 2004/018106 A1 and F1109662 B.
[0007] Finnish patent publication F1109662 B discloses a mobile mineral material processing device, in which the processing units include a vibrating feeder, a jaw crusher, two belt conveyors and a magnetic separator. The device comprises a power source of its own as well as tracks connected to the frame of the device, by means of which it is possible to transport the unit in the working site, and drive it for example on the platform of a truck for road transport between different working sites. Furthermore, in the upper part of the device there is a feeder hopper in which the material to be processed is fed and from which a vibrating feeder transfers the material to a crusher. To facilitate the mobility of the device as well as to attain a height of the cargo that is below the maximum cargo height allowed for road transports, the feeder hopper is composed of walls which can be turned downward and are hinged to the frame of the device. The publication shows an inventive transport locking of a vibrating feeder that facilitates and speeds up the process of bringing the presented crushing device from the working position to the transport position.
[0008] In mineral material processing devices in which a feeder hopper which comprises turning walls is located in the upper part of the device, there are still some unsolved problems relating to the easy and safe mounting of the feeder hopper in a situation in which the feeder hopper of the processing device is transferred from the transport position to the working position or vice versa, from the working position to the transport position.
[0009] The feeder hopper of the mineral material processing device receives strong impacts, when big stones are fed into the feeder hopper. Such impacts may also be exerted on the feeder hopper for other reasons, for example when a device that is feeding the processing device, such as the bucket of an excavator or a bucket loader hits the feeder hopper by accident. Thus, the feeder hopper must be manufactured so that it becomes very firm. At the same time it becomes heavy.
[0010] The feeder hopper is supported against the main frame of the mineral material processing device, wherein the impacts exerted on the feeder hopper are also exerted on the main frame of the mineral material processing device. Thus, this main frame must also be manufactured to be very firm. At the same time it becomes heavy as well. Often the feeder hopper is supported against the main frame by means of a separate feeder module frame. The same requirements as those directed to the main frame are directed thereto, i.e. it must be very firm and it must have a strong structure. At the same time it is often very heavy.
[0011] The mounting of the feeder hopper, i.e. the turning of the heavy walls of the feeder hopper around their hinges to the working position and the locking of the walls to each other is a slow, difficult and dangerous work stage. In the most developed processing devices for mineral materials currently on the market the walls of the feeder hopper can be turned by means of hydraulic cylinders in such a manner that the turning of them from the transport position to the working position and back is easy. However, the impacts exerted on the walls of the feeder hopper cannot be received with mere hydraulic cylinders. Thus, the walls of the hopper must be locked to the working position separately. Conventionally this has been done by means of firm and heavy wedges by means of which the walls are locked so that they do not move with respect to each other and the frame of the processing device for mineral material or the frame of the feeder module. The wedges have been used especially for locking the wall of the feeder hopper and the frame of the processing device for mineral materials, but also for locking the separate walls of the feeder hopper to each other.
[0012] Up until now the transferring of the feeder hopper of a processing device for mineral materials from the working position to the transport position or back has required the climbing of the user up to the hopper to install or remove the locking wedges. In quarry conditions working high up with heavy wedges as well as working between the frame and the heavy wall of the hopper that is attached by means of hinges to the frame is a safety risk.
[0013] In present feeder hoppers there also occurs a problem that the impacts exerted on the feeder hopper, either the impacts on the walls caused by the stones fed into the feeder hopper or other kinds of impacts affect the frame of the processing device, thus causing impacts and vibration therein. As a result of this the frame structure of the processing device itself and all the other structures relating thereto become fatigued and rupture as time goes on. Furthermore, the impacts and the vibration may cause damage to the sensitive components of the processing units and auxiliary devices installed on the frame.
BRIEF DESCRIPTION OF THE INVENTION
[0014] The purpose of the present invention is thus to attain a durable and reliable processing device of mineral materials comprising a feeder hopper with turning walls that can be installed from the transport position to the working position and back easily and safely.
[0015] The invention is based on the idea that the walls of a feeder hopper are locked to a working position with locking means, which can be brought to the locking position without the presence of the user of the processing device near the wedges. In other words, it is not necessary for the user to climb up to the hopper to install or remove the locking wedges belonging to the locking means. According to the invention the locking means include transfer means by means of which the locking means can be transferred to the locking position. The locking means are installed outside the wall of the feeder hopper in a stationary manner, and they contain a locking means that cause the locking, i.e. a movably installed locking wedge and transfer means for transferring the locking wedge to the locking position and out of the same. If desired, the transfer means can be connected to an electrical or hydraulic control system of the processing device, wherein the locking of the walls of the feeder hopper to the working position and the unlocking can be performed by utilizing the control system of the processing device, for example from the control cabin or by means of remote control.
[0016] The locking wedge is also provided with a elastic part that is made for example of rubber, said part attenuating the impacts directed to the walls of the feeder hopper that are caused by the feeding of the mineral material, such as rocks.
[0017] It is an advantage of the invention that the walls of the feeder hopper can be installed and locked from the transport position to the working position and back from a safe place that is located further away from the locking means, without risking the user to physical danger. The locking can also take place by utilizing the control system of the processing device. Furthermore, by means of the elastic part located in the locking means it is possible to attenuate the impacts exerted on the walls of the feeder hopper in such a manner that they do not cause strong impacts and vibration on the frame of the processing device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In the following, the invention will be described in more detail with reference to the appended drawings, in which
[0019] FIG. 1 shows a mobile mineral material processing device in a side view, partly cut open,
[0020] FIG. 2 shows in more detail a feeder hopper of the mineral material processing device of FIG. 1 in a rear view,
[0021] FIG. 3 shows a wall of the feeder hopper according to the invention lifted up into the working position, when seen from outside the feeder hopper, a locking means being attached to said wall,
[0022] FIG. 4 shows a section A-A of FIG. 3 ,
[0023] FIG. 5 shows a section B-B of FIG. 3 , and
[0024] FIG. 6 shows a locking means in a perspective view.
[0025] The main parts of the mineral material processing devices according to FIGS. 1 to 6 include:
main frame 1 feeder 2 frame 3 of the feeder module crusher 4 main conveyor 5 feeder hopper 6 magnetic separator 7 tracks 8 power source 9 side conveyor 10 separating chute 11 grizzly section 12 wall 21 of the feeder hopper wall 22 of the feeder hopper wall 23 of the feeder hopper hinge 24 of the wall of the feeder hopper opening 25 bracket 26 locking wedge 27 locking pin 28 lifting lug 29 locking member, i.e. locking wedge 31 transfer means 32 counter surface 33 of the locking wedge located against the wall of the feeder hopper counter surface 34 of the locking wedge located against the frame of the feeder module rear plate 35 of the locking wedge guiding grooves 36 of the locking wedge fastening and guiding means 37 of the locking wedge front plate 41 of the locking wedge first fastening means 42 of the transfer means elastic element 43 second fastening means 51 of the transfer means elastic element 52 elastic element 53 control means 54 of the elastic element locking means L
DETAILED DESCRIPTION OF THE INVENTION
[0062] FIG. 1 shows a typical prior art mineral material processing device which has been partly cut open in such a manner that the running of the material inside the device can be more easily detected. The main frame 1 of the device is provided with units participating in the processing of mineral material, i.e. a feeder 2 , a crusher 4 , a main conveyor 5 , and a side conveyor 10 . In this case the feeder 2 is positioned on the main frame 1 via the separate frame 3 of a feeder module. The device has a power source 9 of its own that can be for example a diesel engine. The power source drives all processing units of the device by means of electric, mechanical or hydraulic power transmission (not shown). By means of the power source the entire device can move on its tracks 8 .
[0063] In the example according to the figure an excavator feeds the mineral material processing device with construction waste that in addition to concrete blocks contains reinforcement bars used for reinforcing the concrete. The feed material is fed to the feeder hopper 6 underneath of which the feeder 2 is positioned. In this case the feeder is a vibrating feeder that feeds the feed material as a constant flow into the crusher 4 . At the final end of the feeder there is a grizzly section 12 that separates from the feed material the fine-grained substance harmful for the crusher before the feed material enters the crusher 4 . By means of a separating chute 11 the fine-grained substance separated by the grizzly section 12 can be guided away from the processing device either to the side conveyor 10 or—as shown in the figure—to the main conveyor 5 . In this case both the side conveyor 10 and the main conveyor 5 are belt conveyors.
[0064] The crusher 4 reduces the grain size of the feed material. The crushed material falls from the opening of the crusher on the main conveyor 5 that conveys the finished crushed material out of the processing device. The process according to the figure also comprises a magnetic separator 7 that separates the reinforcement bars from the crushed concrete and conveys them out of the processing device to another pile than the crushed concrete.
[0065] FIG. 2 shows in more detail the feeder hopper 6 of the mineral material processing device according to FIG. 1 when seen from behind the mineral material processing device in the travel direction of the feed material. In the situation shown in the figure the feeder hopper 6 is composed of three walls, a left wall 21 , a right wall 22 and a rear wall 23 , attached to the frame 3 of the feeder module in a turnable manner by means of hinges 24 . To illustrate the function of the walls, the right side of the rear wall 23 and the right wall 22 are drawn in working position, i.e. upward, and the left wall 21 is drawn in the transport position, downward. In the working position the walls are tilted upward from the horizontal plane into an angle of 15 to 75 degrees, advantageously into an angle of 30 to 60 degrees so that the feed material fallen on the wall rolls therefrom to the feeder 2 .
[0066] The bottom of the feeder hopper 6 is open in such a manner that the material fed to feeder hopper falls directly on top of the feeder 2 .
[0067] When the feeder hopper is installed in the working position its walls are rotated around their hinges one at a time up to the working position. This may take place for example by lifting the wall with the lifting device by a lifting accessory attached to the lifting lug 29 . Alternatively, for this purpose it is possible to install a hydraulic cylinder (not shown) between the frame of the feeder module and the wall, said hydraulic cylinder rotating the wall around its hinge.
[0068] FIG. 2 shows how the rear wall 23 of the feeder hopper is provided with an opening 25 in which the bracket 26 of the right wall is positioned when the walls are in the working position. The bracket 26 is provided with an opening in which a locking wedge 27 is installed when the walls are locked into the working position. The wedge is locked in its place by means of a locking pin 28 .
[0069] The locking of the walls of the hopper into the working position in the above-described manner is manual work. The bracket 26 on the wall and the locking wedge 27 are located quite high above the ground, wherein there is a risk of falling involved in the installation of the wedge. When installing the wedge, it is necessary to work underneath the upward lifted wall. If an error occurs in the lifting of the wall, and the wall 21 , 22 , 23 can rotate down by gravity around its hinge, there is a risk that the person installing the wedge 27 in its place becomes squeezed between the heavy wall and the feeder 2 or between the wall and the frame 3 of the feeder module.
[0070] FIGS. 3 to 5 show the details of the feeder hopper according to an embodiment of the invention, when the wall 22 of the feeder hopper is lifted up to the working position. FIGS. 3 to 5 will be described in more detail later in this description.
[0071] FIG. 6 shows a locking means L which comprises a locking member 31 , i.e. a locking wedge and transfer means 32 . The first wedge surface of the locking wedge 31 i.e. the rear plate 35 is provided with guiding means, i.e. guiding grooves 36 , to which the fastening and guiding means 37 of the locking wedge are positioned, said fastening and guide means 37 allowing the sliding of the locking wedge 31 on the counter surface 33 of the wall 22 (shown in FIGS. 3 to 5 ) in the vertical direction of the wall, but they prevent the lateral movement of the wedge 31 with respect to the wall 22 . The other wedge surface of the wedge 31 i.e. the front plate 41 is in contact with the counter surface 34 formed in the frame 3 of the feeder module. The locking means L also includes transfer means 32 fastened to the front plate 41 of the locking wedge by fastening means 42 . The transfer means produce the substantially vertical movement of the locking wedge 31 . In this embodiment a double-acting hydraulic cylinder is presented as an example to be used as transfer means 32 . The transfer means 32 can, of course, be any hydraulic, pneumatic or electrically operating actuator. Similarly, the transfer means can also be connected to a hydraulic, pneumatic or electric control system of the processing device.
[0072] If an hydraulic cylinder is used as transfer means, it can be coupled to the hydraulic system (not shown) of the mineral material processing device in a generally known manner so that the moving of the locking wedge 31 to the locking position and out of it can be performed from a safe location further away from the locking wedge 31 and the walls 21 , 22 , 23 than has been possible in solutions known so far. It is, for example, possible to control the movement of the transfer means 32 and thereby the movement of the locking wedge 31 via the control system of the mineral material processing device. During the processing of the mineral material it is possible to monitor the pressure of the hydraulic cylinder 32 by means of the control system (not shown) of the mineral material processing device in such a manner that the pressure prevailing in the cylinder is constant or the variation of the pressure is thus allowed only within predetermined limits. Thus, it is possible to ensure that the locking wedge 31 remains in its place in all situations.
[0073] The front and rear plates 41 and 35 of the locking wedge are made of hard, wear-proof material, for example of steel. Advantageously, there is a elastic part 43 between these that attenuates the impacts exerted on the walls 21 , 22 , 23 during the processing work of the mineral material. Thus, the impacts are not exerted as strongly on the frame of the feeder module 3 and the main frame 1 of the mineral material processing device as before. Thus, it is possible to improve the durability and lifetime of the walls 21 , 22 , 23 themselves, the frame 3 of the feeder module and the main frame 1 of the mineral material processing device. The elastic part 43 is advantageously made of rubber or other resilient material that has been vulcanized, glued or otherwise attached to the front and rear plates 41 , 35 of the wedge 31 . The hardness of the rubber used in the elastic part 43 must be selected in accordance with the type of work for which the processing device for mineral materials is intended, and what kind of impacts can be expected in the hopper in this work. For example rubber whose hardness is “shore 60” is in some applications suitable material for this purpose. It is, of course, possible to use other kinds of generally known resilient, elastic materials, such as polyurethane, instead of rubber.
[0074] The locking wedge 31 can also be formed of a continuous element in such a manner that separate parts such as front and rear plates and a flexible part cannot be distinguished therefrom. Thus, the locking wedge can be for example a continuous metal element.
[0075] FIGS. 3 to 5 show a locking means L attached to the outer surface of the wall 22 of the feeder hopper. FIGS. 4 and 5 show sections A-A and B-B marked in FIG. 3 . In the above-mentioned figures the locking member 34 is in the locking position, i.e. the wall is wedged immobile with respect to the frame of the feeder module.
[0076] The locking wedge 31 is attached in a slidable manner to the wall 22 of the feeder hopper. The path of the transfer means of the locking wedge 31 is in FIGS. 4 and 5 shown by means of an arrow A. The transfer means 32 are used for lifting the locking wedge 31 away from the space formed for the same between the wall 22 and the frame 3 of the feeder module in such a manner that the wall can be turned freely around its hinge 24 down to the transport position. The transfer means 32 are attached from their one end to the wall 22 with fastening means 51 and from the other end to the locking wedge 31 with fastening means 42 , which fastening means allow the moving of the wedge with respect to the wall 22 back and forth in the direction of the stroke of the cylinder 32 .
[0077] Controlling of the movement of the locking wedge 31 on the surface of the wall 22 can also be arranged in other ways than that shown in FIGS. 3 to 6 . To control the wedge, it is possible to provide the wall of the feeder hopper with projections, rails or grooves, or similarly, the wedge can be provided with corresponding parts that guide the movement of the wedge 31 along the wall produced by the transfer means.
[0078] The invention is not intended to be limited to the embodiments presented as examples above, but the invention is intended to be applied widely within the scope of the inventive idea as defined in the appended claims.
[0079] Thus, the invention is not restricted to the number of locking means bringing about the locking between the walls of the feeder and the frame of feeder module: there may be one or several means bringing about the locking on each downward turning wall of the feeder hopper. The invention is not restricted to any specific number of walls either.
[0080] The invention is not restricted to any specific way of moving the side walls of the feeder hopper either. The side walls of the feeder hopper can be lifted up by means of a separate lifter, and lowered down by means of gravity. The invention is implemented best in mineral material processing devices, in which the walls of the feeder hopper can be moved by means of hydraulic cylinders, wherein it is possible to eliminate all manual work stages from the process of transferring the walls of the feeder from the transport position to the working position and vice versa.
[0081] The invention is not restricted to such mineral material processing devices whose frame has been divided into a separate main frame and a feeder module frame. These can also form one common frame.
[0082] Furthermore, the invention is not limited to any particular technology of moving a mobile mineral material processing device. The device can be, for example, mounted on runners, wheels or tracks. It can be moved by means of an external transfer device or it can be a device capable of moving independently.
[0083] The invention is not restricted to the handling of any specific mineral material either. The mineral material can be ore, blasted rock or gravel, different kind of recyclable construction waste, such as concrete, tile or asphalt. The invention is not restricted to situations in which mineral materials are processed with a device suitable for processing of mineral materials: by means of such devices it is also possible to process many other feed materials, such as different kinds of soils and industrial products, side products or waste.
[0084] The invention is not restricted to any specific feeder positioned underneath the feeder hopper. In addition to a vibrating feeder, the feeding device can be for example an apron feeder, a carriage feeder or a feed conveyor.
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Feeder hopper for a movable mineral material processing device, whose walls are arranged to be turned upward to a working position, and which are locked into said working position. To lock the walls, there is at least one locking means in connection with them, said locking means containing at least a locking member and transfer means. According to the method the locking member is transferred to the locking position with the transfer means.
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This is a Division, of application Ser. No. 08/040,957 filed Mar. 31,1993, now U.S. Pat. No. 5,404,041.
FIELD OF THE INVENTION
This invention generally relates to semiconductor device design and more specifically to source contact placement for efficient ESD/EOS protection in grounded substrate MOS integrated circuits.
BACKGROUND OF THE INVENTION
Electrostatic discharge (ESD) and electrical overstress (EOS) are two of the most dominant reliability concerns in the semiconductor industry. The failure susceptibility of integrated circuits (ICs) to ESD and EOS increases as the IC technology progresses towards submicron feature lengths. In spite of the fact that EOS embodies a broad category of electrical threats to semiconductor devices, it is generally accepted that EOS stress sources cause device failure as a result of device self-heating and furthermore, that these sources can be modeled as current sources. This being the case, EOS/EOS immunity of integrated circuits may be qualified in terms of the stress power and/or the stress current required to induce device failure in a specified time.
ESD protection for input, output and/or power supply pins in advanced CMOS ICs is achieved by a protection network that shunts the protected pin and the ground bus under stress events. For input pins, a dedicated protection network that is completely passive under normal operating conditions is added to the input's functional circuitry. For output pins, protection against ESD and EOS is attained with a dedicated protection network whose failure thresholds can in some cases be enhanced by the self-protection capability of the output buffer transistors.
The most common protection schemes used MOS ICs rely on the parasitic bipolar transistor associated with an nMOS device whose drain is connected to the pin to be protected and whose source is tied to ground. The protection level or failure threshold can be set by varying the nMOS device width. Under stress conditions, the dominant current conduction path between the protected pin and ground involves the parasitic bipolar transistor of that nMOS device. This parasitic bipolar transistor operates in the snapback region under pin positive with respect to ground stress events.
The dominant failure mechanism found in the nMOS protection device operating in snapback conditions is the onset of second breakdown. Second breakdown is a phenomena that induces thermal runaway in the device wherever the reduction of the impact ionization current is offset by the thermal generation of carriers. Second breakdown is initiated in a device under stress as a result of the self-heating. The peak nMOS device temperature at which second breakdown is initiated is known to increase with the stress current level. The time required for the structure to heat-up to this critical temperature is dependent on the device layout and stress power distribution across the device.
SUMMARY OF THE INVENTION
Generally, and in one form of the invention, an ESD/EOS protection circuit for protecting an integrated circuit is disclosed. A MOS transistor is connected between a pad to be protected and ground. At least one source contact is located in the source region of the MOS transistor at a first distance from the gate of the MOS transistor. At least one drain contact is located in the drain region of the MOS transistor at a second distance from the gate. The source contact to gate spacing (i.e., the first distance) is designed to be smaller than the drain contact to gate spacing (i.e., the second distance) in order to increase the failure threshold of the protection circuit.
In one embodiment of the invention, the MOS transistor is arranged in a multi-finger configuration. A plurality of source contacts are located in each of the source regions at a minimum distance from an associated gate. A plurality of drain contacts is located in each of the drain regions. A first metal slab extends over and substantially covers each of the drain regions. The first metal slab is in contact with each of the drain regions via the drain contacts. A second metal slab extends over and substantially covers each of the source regions. The second metal slab is in contact with each of the source regions via the source contacts. A third metal slab extends over and substantially covers the MOS transistor. A plurality of metal-to-metal contacts connects the third metal slab with the second metal slab over each of the source regions.
An advantage of the invention is providing an ESD/EOS protection circuit having uniform stress current distribution.
A further advantage of the invention is providing an ESD/EOS protection circuit capable of handling higher stress currents.
These and other advantages will be apparent to those of ordinary skill in the art having reference to the following specification conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a schematic diagram of a prior art ESD/EOS protection circuit;
FIG. 2 is a cross-sectional view a portion of the prior art circuit of FIG. 1;
FIGS. 3a-c are graphs of I-V characteristics for various stress current levels;
FIG. 4 is a graph of stress current level versus the time-to-failure;
FIG. 5 is a cross-sectional view of the preferred embodiment of the invention;
FIG. 6 is a layout diagram of the preferred embodiment of the invention;
FIG. 7 is a schematic circuit model of the circuit of FIG. 6; and
FIGS. 8a-d are cross-sectional views of the preferred embodiment of the invention at various fabrication steps.
Corresponding numerals and symbols in the different figures refer to corresponding parts unless otherwise indicated.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The preferred embodiment of the invention will be described in connection with a grounded substrate MOS IC. It will be apparent to those skilled in the art that the invention is equally applicable to MOS, CMOS and BiCMOS processes.
In MOS technologies, a widely used ESD/EOS protection structure for input, output, and supply pins can be schematically represented by the circuit 10 in FIG. 1. An nMOS transistor 12 is connected between the pin 14 and ground 16. The gate 18 of nMOS transistor 12 is connected to driving circuit 20. Driving circuit 20 is connected between the pin 14 and ground 16. Typically, circuit 10 is implemented in a multi-finger configuration. FIG. 2 show a cross-sectional view of a finger of prior art nMOS transistor 12. Source region 22 and drain region 24 are located in semiconductor body 26. Gate 18 is located above semiconductor body 26 between source and drain regions 22,24. Drain contact 28 and source contact 30 are located on the opposite ends of drain region 24 and source region 22, respectively, from gate 18. The source contact to gate spacing (SCGS) is equal to the drain contact to gate spacing (DCGS).
The failure time of a protection structure may be defined as the time required by the protection structure to reach either silicon melting temperature or the onset of second breakdown for a given stress level measured in terms of the peak stress current. FIGS. 3a-c show the simulated transient current-voltage (I-V) characteristics for three different cases of contact-to-gate spacing. Referring to FIGS. 3a-b, a uniform increase of the DCGS and the SCGS causes an increase of the ballasting resistance and an increase of the snapback voltage. However, referring to FIG. 3c, a substantial reduction in the snapback voltage is attained if minimum SCGS is used. If the areas of drain region 24 and source region 22 are kept equal, the reduced snapback voltage of FIG. 3c translates into reduced nMOS device self-heating for a fixed stress current level. Therefore, structures with minimum SCGS are capable of handling higher stress current level before reaching failure.
FIG. 4 shows the expected behavior of the failure current versus the time to failure for the same three different conditions of the contact spacings. A marginal improvement in the failure current level can be obtained when uniformly increasing the drain and source contact-to-gate spacings. However, a substantial improvement in the failure current level (and thus the failure threshold) can be achieved if the SCGS is kept to a minimum.
A cross-sectional view of a finger 140 of nMOS transistor 102 according to the preferred embodiment of the invention is shown in FIG. 5. Source region 122 and drain region 124 are located in semiconductor body 126. Source region 122 and drain region 124 are of approximately equal size. Source contacts 128 are located such that the SCGS is minimal in order to obtain the improved ESD/EOS performance discussed above. Drain contact 130 is placed on the opposite side of drain region 124 from gate 118. The DCGS is chosen to achieve an appropriate level of drain ballasting resistance.
FIG. 6 shows a preferred layout for the preferred embodiment of the invention. The improved ESD/EOS performance obtained by using minimum SCGS (as determined by the process design rules), is achieved in each device finger 140 of nMOS transistor 102 by placing a row of source contacts 128 at a minimum distance from the gate 118 edge as allowed by the particular design rules. In order to minimize the power density per unit area of the device 100 and therefore improve the device resistance to EOS/ESD, a minimum area for source region 122 is not used. Instead the source 122 and drain 124 areas may be equal, with the drain 124 area determined by the DCGS necessary to achieve an appropriate level of drain ballasting resistance.
FIG. 7 shows a circuit schematic model for the npn parasitic bipolar transistors 150 associated with the multi-finger nMOS layout 102 of FIG. 6. In order to have uniform stress current distribution across the entire device 100, all of parasitic bipolar transistors 150 should operate with the same current level. This can be achieved if the emitter (nMOS source) parasitic interconnect resistances of all the fingers are equal. To accomplish this, a level 2 metal layer 156 interconnects all the sources 122 in the device 100 and provides a solid pad to ground 116 as shown in FIG. 6.
Referring to FIG. 6, each diffusion area (source regions 122 and drain regions 124) is delimited by two polysilicon gates 118. Source regions 122 are covered with a level 1 metal slab 154 and drain regions 124 are covered with a level 1 metal slab 162. The entire nMOS protection device 100 is covered by a level 2 metal layer 156. For each source region 122 in the multi-finger device 100, two rows of source contacts 128 (level 1 metal to source region contacts) are placed each at a minimum distance from the gate 118. The minimum distance is defined as the minimum allowed by the applicable design rules. For example, in a particular 0.5 micron process, the minimum distance may be 0.5 microns. The space in between these two rows of source contacts 128 is then filled by alternating level I metal to level 2 metal contact rows 160 with rows of source contacts 128. The level 2 metal layer 156 interconnecting all the source regions 122 is then connected to the chip ground 116. Each one of the drain regions 124 is covered with a level I metal slab 162 and a single row of drain contacts 130 is placed at a distance DCGS from the neighboring gate 118 edges. All level 1 metal slabs 162 are then interconnected outside the active area by another level 1 metal strap 166 that can then be tied to the pad 168 to be protected.
A preferred method of forming circuit 100 will now be described with reference to FIGS. 8a-d. Referring to FIG. 8a, a plurality of gates 118 are formed over the surface of semiconductor body 126 by conventional techniques. For example, a polysilicon layer may be deposited over a thermally grown gate oxide layer 114 and etched to form gates 118. Next, a plurality of source regions 122 and a plurality of drain regions 124 may be implanted on opposite sides of gates 118 such that one of said source regions 122 is located on one side of each gate 118 and one of said drain regions 124 is located on the other side of each gate 118. Source regions 122, drain regions 124 and gates 118 comprise a multi-finger nMOS transistor 102. A layer of insulating material 125 is deposited and etched as shown in FIG. 8a.
Referring to FIG. 8b, a layer of conductive material is deposited and etched to form a plurality of drain contacts 130 and source contacts 128. Drain contacts 130 are formed over each of the drain regions 124 at a distance of DCGS from the adjacent gates 118 to connect metal slab 162 to drain region 124. Source contacts 128 are formed over each source region 122 to connect metal slab 154 to source regions 122. Preferably, source contacts 128 are arranged in rows such that one row of source contacts 128 is at a minimum distance from the adjacent gate 118, as shown in FIG. 6. Next, a layer of metal I is deposited and etched to form metal slab 162 over drain regions 124 and metal slab 154 over source regions 122.
Referring to FIG. 8c, an insulator layer 155 is deposited over the surface and etched. A conductive layer is deposited and etched to form a plurality of level 1 metal to level 2 metal contact rows 160 over source regions 122, as shown in FIG. 8d. Finally, a layer of level 2 metal 156 is deposited over insulator layer 155 and level 1 metal to level 2 metal contact rows 160.
A few preferred embodiments have been described in detail hereinabove. It is to be understood that the scope of the invention also comprehends embodiments different from those described, yet within the scope of the claims.
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.
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An ESD/EOS protection circuit (100) for protecting an integrated circuit. A MOS transistor (102) is arranged in a multi-finger configuration having a plurality of drain regions (124), a plurality of source regions (122) and a plurality of gates (118). A first metal layer (162) substantially covers each of the drain regions (124) and is in contact with each of the drain regions (124) via drain contacts (130). A second metal layer (154) substantially covers each of the source regions (122) and is in contact with each of the source regions via source contacts (128). A plurality of source contacts (128) are located at a minimum distance from gates (118). Metal-to-metal contacts (160) connect a third metal layer (156) with the second metal layer (154) over each of the source regions (122).
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This application claims priority under 35 U.S.C. §119 to patent application no. DE 10 2010 028 751.2, filed May 7, 2010 in Germany, the disclosure of which is incorporated herein by reference in its entirety.
BACKGROUND
The present disclosure relates to a guide rail for a hand-held power tool.
Such a guide rail, which is designed to guide an electric hand-held tool such as, for example, a hand-held circular saw, router or compass saw onto the workpiece to be worked, is known from DE 10 2004 017 420 A1. The electric hand-held tool can be displaced along a guide groove in the guide rail, to enable a straight cut to be made. A slide block, which is connected to the hand-held power tool, slides in the guide groove of the guide rail.
To enable longer cuts to be made, the guide rail can be connected to an extension rail. For this purpose, the end face of the guide rail has a plurality of receiving openings, in which pegs that are disposed on the axial end face of the extension rail can be inserted.
Since the pegs on the end face of the extension rail can only be inserted in associated receiving openings, there is a risk, as a result of the working of the workpiece and the forces acting upon the rail during such working, of the connection between the guide rail and the extension rail becoming at least partially released and the extension rail becoming skewed relative to the guide rail and assuming an angle, which can negatively affect the work result.
A further disadvantage is the unergonomic handling of the guide rail and extension rail.
SUMMARY
The disclosure is based on the object of simplifying the handling of a guide rail for a hand-held power tool, which guide rail is composed of at least two individual rail elements. According to a further aspect of the disclosure, a clean cross section is to be ensured.
This object is achieved, according to the disclosure, by the features of set forth herein.
The guide rail according to the disclosure is used to guide a hand-held power tool, in particular an electric hand-held power tool such as, for example, a hand-held circular saw, a router or a compass saw, in order to ensure a straight cut in the workpiece to be worked during the sawing operation, by means of the hand-held power tool. The hand-held power tool is put onto the guide rail, which, for example, is provided with a guide groove, in which a slide block or the like of the hand-held power tool can be inserted in a sliding manner. The guide rail comprises at least two rail elements, which can be locked together by means of a releasable connecting device and can be joined to form a common rail. In the case of the guide rail according to the disclosure, the connecting device is realized as a joint device, which allows the individual rail elements to be pivoted between a folded-together, non-functioning position and a functioning position in which the individual rails, or rail elements, lie in a common plane. Preferably, the rail elements, when in the functioning position, extend along a common longitudinal axis, a functioning position in which the rail elements are disposed parallelwise in relation to one another also being possible in principle.
The joint device via which the rail elements are pivotally coupled to one another significantly improves the ergonomics, or handling, of the guide rail. When in the non-functioning position, the rail elements are folded together and, in particular, are in a position in which they lie on one another, such that the pack size in the folded-together state does not exceed the size of an individual rail in respect of the length and width, and is larger only in thickness. In the folded-out state, the rail elements are preferably pivoted by 180° relative to the non-functioning position, the pivoting motion between the non-functioning position and the functioning position being easily effected. In the non-functioning position with the rail elements lying on one another, the latter form a rail stack that is easily transported and stored, owing to the compact pack size. In the folded-out, functioning position, the rail elements assume the desired relative angle in relation to one another, owing to the kinematic coupling via the joint device. In particular, a coaxial alignment of the rail elements is achieved, such that the guide rail forms a rectilinear seating for guiding the hand-held power tool.
According to an expedient embodiment, a latching device is provided, by means of which the individual rails can be latched to one another, at least in the functioning position. In principle, however, it is also possible for the individual rails to be latched to one another also in the non-functioning position by means of the latching device, or a further latching device. In the functioning position, the latching device offers the advantage that inadvertent folding together by means of the joint device is prevented. Conversely, in the non-functioning position, inadvertent folding out of the rail elements is precluded because of the latching device.
The latching device is realized, for example, as a displaceable locking bar, which is preferably to be displaced in the axial direction along rail elements. In the latching position, the displaceable locking bar overlaps the end face of adjacent rail elements and thereby prevents the rail elements from being folded together. In order to achieve the non-functioning position, the locking bar must be displaced into its non-latching position, whereupon the rail elements can be folded about the pivot axis into the non-functioning position.
Embodiments in which the latching device is realized so as to be separate from the joint device and embodiments in which the latching device is a constituent part of the joint device are both possible. This is the case, for example, if the joint device comprises two slide strips and one intermediate joint unit that is pivotally connected to each slide strip, the slide strips being displaceably received in the rail elements. In this embodiment, the entire joint device is to be displaced along the rail elements, the joint device being displaced, for the purpose of changing over the rail elements between the non-functioning position and the functioning position, into a position in which the joint unit of the joint device is located between the rail elements. In order to achieve locking of the rail elements in the functioning position, on the other hand, the joint device is displaced axially to such an extent that the joint unit is located outside the end edge region between the two rail elements and, instead, the end edge region is overlapped by a slide strip of the joint device. Thus, at least one of the slide strips performs the function of a displaceable locking bar.
According to a further expedient embodiment, it is provided that the joint device comprises a respective hinge on each rail element, the hinges being able to be pivotally coupled to an intermediate joint piece. The hinges, which in the position of use are fixedly connected to the associated rail element, have, for example, a shaft receiver, in which a joint shaft on the joint piece can be inserted. The hinges are preferably composed of plastic, and can be inserted in end-face recesses in the individual rails. According to a further expedient embodiment, two shaft receivers, which are disposed with an axial offset, are provided on at least one hinge of the joint device, in which shaft receivers the joint shaft of a joint piece can be inserted, respectively, each of the shaft receivers expediently constituting a latching position. Depending on the position of the joint shaft in the one or other shaft receiver, the joint device has a differing length, the shorter length being assumed in the functioning position and the greater length serving to effect the adjustment between the functioning position and the non-functioning position, in order to have a sufficiently large motion space for the pivoting motion.
Even if the hinge is provided only with one shaft receiver for the joint shaft on the joint piece, the shaft receiver expediently constitutes a latching position. In order to obtain the required motion space for the pivoting motion, at least one hinge can be received, if necessary, so as to be also longitudinally displaceable on the rail element concerned.
In principle, any number of rail elements can be pivotally coupled together by means of joint devices and together constitute the guide rail. Thus, for example, it is possible for three or more rail elements to be respectively coupled to one another in a Z-shaped fold by means of end-face joint devices.
Further advantages and expedient embodiments are disclosed by the description and drawings below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a perspective view of a guide rail having a total of three guide elements, which are represented in a folded-together, non-functioning position, lying on one another, the rail elements being connected to one another in a jointed manner,
FIG. 2 shows a detail representation of a plastic hinge that can be inserted in a recess in a rail element and is a constituent part of a joint device between two rail elements,
FIG. 3 shows a perspective view of the end face of the rail elements folded together to form a stack,
FIG. 4 shows the rail elements of the guide rail in the folded-out functioning position,
FIG. 5 shows an enlarged detail representation from the transition region between adjacent rail elements in the functioning position, having a displaceably disposed locking bar, which constitutes a latching device for locking the rail elements in the functioning position,
FIG. 6 shows, in a further embodiment, a guide rail having three rail elements in the non-functioning position, in which the joint device comprises two slide strips and an intermediate joint unit, the slide strips being displaceably received, respectively, in a rail element,
FIG. 7 shows an enlarged view of the joint device between the rail elements folded together in the non-functioning position,
FIG. 8 shows a view of the underside of the guide rail, with the individual rail elements in the folded-out functioning position,
FIG. 9 shows a perspective representation of the guide rail in the functioning position,
FIG. 10 shows the folded-together rail elements in the non-functioning position, with transport cap pieces fitted on the end faces and connected by a transport strap.
In the figures, components that are the same are denoted by the same references.
DETAILED DESCRIPTION
Represented in FIGS. 1 to 5 is a guide rail 1 consisting of three individual rail elements 2 , which are each pivotally coupled to one another by means of end-face joint devices 3 . In FIG. 1 , the guide rail 1 is shown in the folded-together state, which constitutes the non-functioning position, and in which the individual rail elements 2 are stacked such that they lie directly on one another. The rail elements 2 are each identical to one another in their structure, and can be folded out, in a Z-shaped fold, between the non-functioning position represented in FIG. 1 and the functioning position shown in FIGS. 4 and 5 , in which the rail elements 2 adjoin one another at the end faces and are aligned coaxially in relation to one another, such that a continuous seating surface is obtained for guiding a hand-held power tool. The reference 15 denotes the separation line between two rail elements 2 placed against one another without a gap.
Each rail element 2 is provided with a locking bar 4 , which is displaceably mounted on the top side of one of the rail elements, and which constitutes a latching device by means of which the rail elements are latched in the functioning position and secured against being inadvertently folded together. In the non-latching position according to FIG. 1 , the locking bar 4 is in the retracted state, in which the locking bar 4 in its entirety is located on the top side of a rail element 2 and extends maximally only as far as the end edge of the rail element. By contrast, in the latching position, which is represented in FIGS. 4 and 5 , the locking bar 4 overlaps the end edges of adjacent rail elements, which are combined to form the common guide rail and adjoin one another axially. Since only a pivoting or folding motion in one direction is possible, either because of kinematic limitations in the joint device 3 or on account of the end-face seating of adjacent rail elements, overlap of the locking bar 4 on only one side of the rail elements 2 suffices for securing against inadvertent folding together. For the changeover from the functioning position according to FIGS. 4 and 5 into the non-functioning position according to FIG. 1 , the locking bar 4 must be pushed back, out of the position in which it overlaps the end edge, into the non-latching position, in which the locking bar is at a distance from the end edge. The locking bar 4 is disposed parallelwise in relation to the joint device 3 , and is to be displaced along the top side of the rail elements 2 , in the direction of the longitudinal axis of the guide rail.
The joint device 4 consists of two hinges 5 , which are each realized as a plastic component and are fixedly inserted in an end-face recess in the rail elements 2 . Furthermore, the joint device 3 comprises a joint piece 8 , which, at opposing end faces, is provided with a respective joint shaft 9 that is pivotally received in a shaft receiver 6 or 7 realized in the hinge 5 . In the joint device 3 , therefore, there exists the possibility for pivoting about two axially offset, parallel joint shafts, which are realized on the joint piece 8 . Each joint shaft 9 is received in a shaft receiver 6 or 7 in the hinge 5 .
Each hinge 5 has two shaft receivers 6 and 7 , which are adjacent but offset parallelwise in relation to one another with axial spacing, and which are each realized as latching recesses, such that the joint shaft 9 is in a latching position in each of the two shaft receivers 6 and 7 , but can be turned in the shaft receiver. Owing to the axial offset between the shaft receivers 6 and 7 —as viewed in the longitudinal direction of the rail elements—the total axial length of the joint device 3 , consisting of two hinges 5 and the intermediate joint piece 8 , can be set in a variable manner. If the joint shaft 9 is in the front shaft receiver 7 that faces towards the end face, the total axial length is greater than if the joint shaft 9 is positioned in the rear shaft receiver 6 , which is at a greater distance from the end face. For the changeover motion between the non-functioning position and the functioning position, therefore, it is possible to bring the joint device into the position having a greater axial extent, such that there is more motion clearance available for the pivoting motion and blocking resulting from self-collision between the rail elements is precluded. In the non-functioning position according to FIG. 1 , also, the joint device 3 assumes the axially lengthened position. To achieve the functioning position according to FIGS. 4 and 5 , on the other hand, the joint device 3 is brought into the axially shortened position, in order to ensure that the end faces of adjacent rail elements 2 contact one another and that a continuous, gapless guide rail is formed.
A further exemplary embodiment for a guide rail 1 is represented in FIGS. 6 to 10 . The guide rail 1 comprises three individual rail elements 2 , which are each pivotally coupled to one another in a Z-shaped fold by means of joint devices 3 . In this case, in the non-functioning position, which is represented in FIGS. 6 , 7 and 10 , the joint devices 3 are located between, respectively, two directly adjacent rail elements 2 that are coupled together, on opposite sides of the rail stack.
The joint device 3 in the second exemplary embodiment differs from that of the first exemplary embodiment. As can be seen from FIGS. 7 and 8 in particular, the joint device 3 comprises two slide strips 10 and 11 , which are each displaceably disposed in adjacent rail elements 2 , and comprises an intermediate joint unit 12 that is coupled to each slide strip 10 and 11 , respectively, in a jointed manner. Each of the slide strips 10 , 11 is held so as to be displaceable in the axial direction of the rail elements 2 . In the exemplary embodiment, guides 13 and 14 are provided for this purpose on the top side of the rail guide, which guides are realized so as to be integral with the guide rail, and extend in the direction of the longitudinal axis of each rail element.
In FIGS. 6 , 7 and 10 , the guide rail 1 is represented in the non-functioning position, with rail elements 2 lying over one another. FIGS. 8 and 9 , by contrast, show the guide rail 1 in the folded-out functioning position, in which the individual rail elements 2 have been folded by 180° relative to the non-functioning position. As can be seen, in particular, from the view of the underside according to FIG. 8 , immediately after folding out the joint unit 12 is located level with the separation line 15 between two adjacent rail elements 2 adjoining one another at the end faces. When the joint unit 12 is in this position, the rail elements 2 pivotally coupled by means of the joint device 3 can be pivoted into the folded-together position. If, on the other hand, the slide strips 10 and 11 , including the joint unit 12 that is coupled to the rail strips in a jointed manner, is displaced in the direction of the longitudinal axis of the rail elements 2 , the joint unit 12 comes into an axial position outside the separation line 15 , and at the same time the separation line 15 denoting the meeting end faces of adjacent rail elements 2 is overlapped by one of the slide strips 10 or 11 . The adjacent rail elements 2 that are coupled to one another by means of the joint device 3 are thereby latched by means of the joint device 3 and secured against a pivoting motion, such that the joint device 3 additionally assumes the function of a latching device.
In the exemplary embodiment, two joint devices 3 , disposed next to one another, are provided to connect two adjacent rail elements 2 .
As represented in FIG. 7 , a latching element 16 is inserted in the guides 13 and 14 , respectively, which latching element is to be brought into a latching position with a corresponding latching element on one of the slide strips 10 or 11 , respectively. The non-functioning position represented in FIGS. 6 , 7 and 10 thus also constitutes a latching position.
As can be seen from FIG. 10 , for transport purposes the guide rail 1 , with the rail elements lying on one another in the non-functioning position, can be provided with transport cap pieces 17 , which can be placed on the end faces and connected via a transport strap 18 . The rail elements 2 lying on one another are enclosed by the transport cap pieces 17 at the end faces.
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A guide rail for a hand-held power tool includes at least two rail elements, which are to be joined together to form a common rail and which are held on one another by means of a releasable connecting device. The connecting device includes a joint device, by means of which the individual rails can be pivoted between a folded-together non-functioning position and a functioning position that lies in a common plane.
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This is a continuation of application Ser. No. 398,935 filed Aug. 16, 1973, and now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel control system for supercharged, fuel injected internal combustion engines, in particular diesel engines employing exaust gas turbo-chargers. The individual control units of the control system each comprise a movable partition which is displaceable against the force of at least one return spring in dependence on the intake air pressure of the engine. The movable partitions are connected to a setting member by means of which the operating region of a supply quantity adjustment member of the engine injection system is changeable in the direction of increasing supply quantity during a period of increasing intake manifold air pressure.
2. Description of the Prior Art
Known control systems of the above-mentioned construction which are also designated as manifold pressure dependent full load stops or smoke limiters, are installed either at the injection pump or at the corresponding regulator of the engine, and their setting member influences either the position of a full load stop for the limitation of the control rod path or it limits the maximum excursion of the adjustment lever of the regulator attached to the injection pump, or again, it interacts with the control linkage in such a way as to change the position of the control rod of the injection pump from that which may have been set by the regulator to a new position lying further in the direction of increasing supply quantity, the magnitude of the change depending on the magnitude of the intake manifold air pressure. These known control systems have the disadvantage that the controlled increase of the fuel quantity during acceleration of the engine occurs with a time delay, because the manifold air pressure is used to measure the fuel increase and, in engines employing exhaust gas turbo-chargers, the manifold air pressure increases only after an increase of the exhaust gas pressure and of the exhaust gas temperature. This mutual dependence of fuel quantity, intake manifold pressure and exhaust gas pressure determines the acceleration characteristics of an engine equipped with an exhaust gas turbo-charger and employing the known control system. These acceleration characteristics are often incapable of meeting the demands made especially on modern vehicular diesel engines.
In order to achieve a more rapid acceleration of the engine, it would be possible, in principle, to increase the fuel quantity metered by the control system so that the desired acceleration of the engine would be achieved. This method has the considerable disadvantage, however, that during full load operation and during constant speed operation, the engine then develops inadmissible amounts of smoke.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to avoid the above-mentioned disadvantages inherent in a control system of the above-mentioned construction and to improve this system in such a way that during the acceleration of the engine, a higher than normal fuel quantity is metered but that this increase can be regulated away, i.e. it is cancelled during the constant speed operation of the engine.
It is a more specific object of the present invention to provide a control system including a supplementary control unit having a flow-restricting delay member, the supplementary control unit imparting an additional displacement to a fuel control setting member.
These and other objects of the present invention are attained in that the position of the setting member is made to be additionally changeable by means of a supplementary second pneumatic control unit having delayed feedback characteristics and employing a second movable partition which is acted on by a differential pressure of a pneumatic control medium, the pressure being a measure of the acceleration of the engine. During a period of increasing pressure of the control medium, the setting member tends to be displaced, in the direction of increasing fuel supply quantity, beyond the position that was set by the first movable partition, and during a constant speed operation, this position change is reversible to a zero value by the effect of an increasing counter pressure exerted by the control medium and delayed by the action of a delay member. In this way, the so-called "lag" of the manifold pressure can be compensated for simply and advantageously without also increasing the normal fuel injection quantity which properly corresponds to a given manifold air pressure, during periods of constant speed operation of the engine.
A particularly advantageous embodiment of the present invention is achieved by letting the air in the intake manifold serve as the control medium and by using the instantaneous difference between the intake manifold air pressure which increases during acceleration of the engine and the counter air pressure which increases at a lower rate due to a delay member, to define the magnitude of the differential pressure. In this way, the expense of a second pressure source is avoided and the conduits are simplified. This does not exclude the possibility of using other pneumatic control media, especially for particularly precise control of the supplementary control unit, and this can be, for example, an rpm-dependently increasing air pressure.
In the subsequent description, the symbol P L will designate the instantaneous value of the full intake manifold air pressure and the symbol P LV will designate the instantaneous value of the pressure prevailing downstream of a delay member which contains a flow throttle and is connected to the intake manifold.
During increases of P L , P LV also increases, but at a lower rate, due to the presence of the delay member. Thus during increases of P L , the instantaneous values of P LV are always lower than those of P L , i.e. P LV lags behind P L or it is "delayed".
Similarly, P AB will designate the full exhaust gas pressure and P AV will designate the delayed exhaust gas counter pressure.
The symbol P AT will designate the ambient or atmospheric air pressure.
A simple and neat contruction of the supplementary control unit derives from letting only the second movable partition effect the supplementary position change of the setting member and from providing that the primary pressure side of the partition is acted on by the full manifold air pressure P L , and that the counter pressure side is acted upon by the delayed increasing manifold air counter pressure P LV , delayed by the delay member.
Furthermore, it is advantageous that the movable partitions are two diaphragms which are fastened to connecting rods pivotably attached to the two ends of a two-armed lever, whose center is pivotably connected to the setting member. The two lever arms transmit the travel of both diaphragms in diminishing ratio to the setting member; the independently carried out setting of the two diaphragms and of the two lever arms makes possible a very precise adaptation of the control system to the prescribed control motions.
It is advantageous to make the pre-tension of the return spring which loads the first diaphragm changeable by means of an adjustable support bushing which is screwed into the housing of the control system and which also serves as a guide sleeve for the connecting rod of the first diaphragm.
A further advantageous embodiment of the present invention is that the movable partitions are formed by two coaxial and sequentially disposed diaphragms, of which the first diaphragm is fixedly connected with the setting member and the second diaphragm acts through a connecting rod on the setting member, so that very few moving parts are present.
In order that the forces exerted by both diaphragms be additive, an advantageous embodiment of the invention is characterized in that the two diaphragms define and separate four chambers, of which the two chambers which are contiguous to the primary pressure sides of the two diaphragms are acted upon by the full manifold air pressure P L , the chamber which is contiguous to the counter pressure side of the first diaphragm is acted upon by ambient air pressure P AT , and the chamber contiguous to the counter pressure side of the second diaphragm is acted upon by the increasing manifold air counter pressure P LV , delayed by the delay member.
Another advantageous embodiment of the present invention is provided in that the second diaphragm is made larger than the first diaphragm and that these two diaphragms separate three chambers from one another, of which the chamber contiguous to the primary pressure side of the second diaphragm experiences the full manifold air pressure P L , the middle chamber which is contiguous simultaneously to the counter pressure side of the second diaphragms and the pressure side of the first diaphragm is acted upon by the delayed increasing manifold air counter pressure P LV , and the chamber which is contiguous to the counter pressure side of the first diaphragm is acted upon by ambient air pressure. This advantageous arrangement of both diaphragms requires only a small construction space and, during a constant speed operation of the engine, substantially only the area of the smaller diaphragm is effective.
Because the increase of the exhaust gas pressure with rpm occurs faster that that of the manifold air pressure, a further advantageous embodiment of the present invention is achieved when the control medium is exhaust gas and the second movable partition is affected by the full exhaust gas pressure P AB acting on its primary pressure side for effecting the supplementary position change of the setting member, whereas the counter pressure side of the partition is acted upon by the delayed increasing exhaust gas counter pressure P AV , delayed by the delay member.
A simple influence on the feedback time constant is achieved in that the delay member contains, in a known manner, a flow throttle which is inserted in a supply channel leading to the chamber contiguous to the counter pressure side of the second movable partition. Furthermore, it is provided that, parallel to the flow throttle, a check valve is so disposed that it makes possible an unthrottled return flow of the control medium from the chamber contiguous to the counter pressure side of the second movable partition by which means a rapid adaptation of the control system to the decreasing pressure of the control medium is possible during deceleration of the engine.
In order to influence the response threshold and the control characteristics of the supplementary control unit, an advantageous embodiment of the present invention is that the counter pressure side of the second movable partition is loaded by the return spring, and its pressure side is loaded by an equalization spring whose pre-tension acts in opposition to the pre-tension of the return spring.
In order to guarantee a reliable operation of the control unit for any value of the pressure of the control medium, it is provided in a further advantageous development of the present invention that the second movable partition comprises two coaxial, sequentially disposed diaphragms of equal size, which are connected by a connecting rod which in turn is pivotably connected to the setting member, and where the primary pressure side of one diaphragm experiences the full manifold air pressure, and the corresponding primary pressure side of the other diaphragm acts as the counterpressure side of the second movable partition and experience the delayed increasing manifold air counter pressure. In this way the influence of the connecting rod on the pressure-related forces acting on the diaphragm is eliminated.
In order to eliminate the influence of the connecting rod on the forces acting on the diaphragm and at the same time to avoid using guide bushings which must be sealed against the manifold pressure, a further advantageous development of the present invention is achieved by having two coaxial, sequentially disposed and oppositely acting diaphragms of different diameter serve as the movable partitions. They are connected with one another by a connecting rod which further attaches to the setting member and the larger of the two diaphragms is exposed to the full manifold air pressure whereas the smaller of the two diaphragms is exposed to the delayed increasing manifold air counter pressure so that, during constant rpm of the engine, only the differential area of the two diaphragms is effective; the space surrounding the connecting rod and lying between the two diaphragms being exposed to ambient air pressure.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing, seven exemplary embodiments of the control system according to the present invention are illustrated and are described further below.
FIG. 1 is a partial cross sectional view in elevation illustrating one exemplary embodiment of the control system according to the present invention including details of a first and supplementary control units;
FIG. 2 is a partial cross sectional view in elevation illustrating a second exemplary embodiment of the control system according to the present invention;
FIG. 3 is a partial cross sectional view illustrating a third exemplary embodiment according to the present invention;
FIG. 4 is a partial cross sectional view illustrating a fourth exemplary embodiment according to the present invention;
FIGS. 5 - 7 are more schematic illustrations of three additional exemplary embodiments according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the first exemplary embodiment illustrated in FIG. 1, there is shown a housing 10, in which two control units 11 and 12 are disposed parallel to each other. The first control unit 11 incorporates a movable partition in the form of a diaphragm 13 which is fixedly attached to one end of a connecting rod 14 whose other end is pivotably fastened to an end 15 of a two-armed lever 16. The center of the diaphragm 13, which is attached to the connecting rod 14, is fixed between two discs 17 and 18. The disc 18 serves also as a spring support for a return spring 19 which loads the diaphragm 13. The end of the spring 19 which faces away from the disc 18 bears on an adjustable support bushing 21 that is screwed into the housing 10 of the installation. The bushing 21 is rotatable by means of a tool inserted into depressions 22 for the purpose of changing the pre-tension Pvl of the return spring 19. The adjustable support bushing 21 also serves as a guide bushing for the connecting rod 14 and has a serrated edge 23, which engages a detent spring 24 for securing a rotation position of the bushing 21.
In a known manner the diaphragm 13 is hermetically joined to the housing 10 by a cover 25 and separates two chambers 26 and 27 from one another. The chamber 26 communicates through a connecting bore 28 with an intake manifold air line 29 which is shown only schematically. The intake manifold air is admitted to the chamber 26 through the intake air line 29 and acts on one side of the diaphragm 13 which is designated 31. The pressure P L of the intake air serves as the pneumatic control medium. The side designated 32 will be referred to as the counter pressure side. The side 32 seals off the chamber 27 from the chamber 26 and is itself acted on by an ambient air pressure P AT , since the chamber 27 always has an open communication to the outside through a bore 33. The drawn rest position of the diaphragm 13 is determined firstly by the pre-tension of the return spring 19 and secondly, by a fixed stop, consisting of a cylindrical cap 34. The cap 34 is fixedly attached to the cover 25 and contains the connecting bore 28. The cap 34 is also provided with slots 34a through which intake manifold air streaming through the connection bore 28 can flow into that part of the chamber 26 that lies outside of the cap 34 when the disc 17 abuts the cap 34.
Control unit 11 operates in a known manner in dependence on the intake manifold air pressure of the engine, and parallel to this control unit 11 there is disposed the second control unit 12 which employs a second movable partition in the form of a diaphragm 35. On one side, designated 36, of the diaphragm 35, there acts the full manifold air pressure P L which is communicated through a branch line 29b. On the counter pressure side, designated 37, there acts a delayed increasing air counter pressure P LV . The counter pressure P LV builds up with a delay due to a delay element 38. The delay element 38 consists of a threaded insert which is screwed into a threaded bore 39 in the wall of the housing 10, and which serves as a supply channel containing a flow throttle 41 formed as a narrow bore. The threaded insert 38, in addition to the flow throttle, 41, also contains a connecting thread 42 to which a branch line 29a of the manifold air line 29 is connected. The diaphragm 35 divides the interior of the control unit 12 into chambers 43 and 45. The counter pressure side 37 is acted upon by the intake manifold pressure P LV as a result of intake manifold air streaming through the flow throttle 41 and into the chamber 43, whereas the primary pressure side 36 is acted upon by manifold air pressure P L , which streams without throttling through a connecting bore 44 into the chamber 45. The shown rest position of the diaphragm 35 is determined, in the same way as in the first control unit 11, by a cap 40 serving as a stop.
Diaphragm 35 serving as the second movable partition similar to the first diaphragm 13, is attached to a connecting rod 46 whose one end is pivotably fastened to an end 47 of the two-armed lever 16. The lever 16 has a central pivot which is formed by a bolt 48 which pivotably connects lever 16 to a setting member 49. The connecting rod 46 is guided in a guide bushing 51. The bushing 51 is provided with a packing 52 that seals off the chamber 43 from the outside.
As with the first movable partition 13, the second movable partition 35 is loaded on its counter pressure side 37 by a return spring 53, which is opposed on the primary pressure side 36 by a compensating spring 54. The pre-tension Pv3 of the spring 54 acts in opposition to the pre-tension Pv2 of the return spring 53. The oppositely acting compensating spring 54 permits a very exact setting of the response threshold of the second control unit 12. The return spring 53 determines the characteristics of the second control unit, which operates as a supplementary control unit with delayed feedback in the manner of a pneumatic differentiating unit. The cooperation of the two control units will be described more fully below.
The setting member 49, in a known manner not shown in FIG. 1, acts upon the operating region of a supply quantity adjustment member belonging to the injection system of a diesel engine equipped with an exhaust gas turbo-charger. In FIG. 2 there is exemplarily shown an embodiment in which the setting member limits the motion of a stop mounted on a centrifugal rpm regulator for the limitation of the maximum full load position of a control rod serving as a supply quantity setting member in an injection pump.
This second exemplary embodiment shown in FIG. 2 differs from the first exemplary embodiment of FIG. 1 especially in that the movable partitions are embodied as two coaxial and serially disposed diaphragms 61 and 62. The first diaphragm 61 is fixedly attached to a connecting rod 63, which serves as a setting member. The second diaphragm 62 actuates another connecting rod 64, whose one end 65 presses against one end 63a of the connecting rod 63. The other end 63b of the connecting rod 63 is developed as a fork and, through the intermediate action of a bolt 66, actuates an angled lever 57 mounted within the housing 10' of the control unit. The angled lever 57, in turn, limits the position of a full load stop 68 which forms part of a centrifugal rpm regulator 69 (only partly shown). The full load stop 68 consists of a limit bolt 72 guided in a guiding bushing 71. The bolt 72 has a head 73 which serves as an abutment for the nose 74. The nose 74 abuts the head 73 in a known manner whenever the control rod 75, serving as the supply quantity setting member of the injection pump not further shown, is moved by a control lever 76, of the centrifugal rpm regulator 69, in the direction of arrow A for the purpose of regulating a maximum quantity of injection fuel. The limit bolt 72 is held in its shown position by a spring 77, and, in this position, a stop nut 78 engages a butting surface 79 of the angled lever 67. An abutment screw 81 limits the path of the angled lever 67 and therefore also limits the maximum position change (Δs max) of the setting member 63 which may be regulated by the control unit in dependence on the intake manifold air pressure P L .
The diaphragm 61 separates a chamber 82 lying above this diaphragm from a chamber 84 which houses two return springs 83 and which is open to the ambient air pressure P AT through a bore 33. The chamber 82 communicates through the connection bore 28 with the intake air line 29, and therefore receives the full intake manifold air pressure P L . An intermediary wall 85 belonging to a second housing 86 contains a guide bore 87 to receive connecting rod 64 of the second diaphragm 62 and includes a labyrinth seal 88. This intermediary wall 85 also contains the delay element 38 which is inserted into the threaded bore 39. The delay element 38 includes the flow throttle 41. The intermediary wall 85 further contains a check valve 89 lying parallel to the delay member 38.
The second diaphragm 62 separates a chamber 92, defined by the intermediate wall 85 and by the counter pressure side 91 of the diaphragm 62, from another chamber 93 to which the full intake air pressure P L occurring in the intake manifold pressure line 29 is communicated through the branch line 29b. The primary pressure side 94 of the diaphragm 62 is acted upon by the full manifold pressure P L , whereas the counter-pressure side 91 of this diaphragm 62 experiences the counter pressure P LV whose increase is delayed by the delay member 38. As was the case with the diaphragm 35 in FIG. 1, the diaphragm 62 is tensioned between two springs 53 and 54, and the shown rest position is determined by an abutment plate 95. The primary pressure side 96 of the first diaphragm 61 experiences the manifold air pressure P L , and the counter pressure side 97 experiences the ambient air pressure P AT . In this construction of the control system, the supplementary control unit 98 is equipped with a second diaphragm 62 and operates both against the force of the return spring 53 as well as against the force of the return springs 83 of the first diaphragm 61. In addition, the check valve 89 makes possible a pressure equalization between the chamber 92 and the chamber 82 in the even of rapid pressure variations. If the control characteristics permit it, the return spring 53 can be omitted, and the return force can be provided by only springs 83.
The control system according to the third exemplary embodiment shown in FIG. 3, includes a supplementary control unit 100 which has a diaphragm 101. And just as the second exemplary embodiment of FIG. 2, the embodiment of FIG. 3 has two coaxial and sequentially disposed diaphragms 61 and 101, which however, in contrast to the two diaphragms 61 and 62 of the second exemplary embodiment of FIG. 2, separate from one another only three chambers 84, 102 and 103. The first diaphragm 61 and the only partially shown housing 10' correspond to those already shown in FIG. 2 and are therefore designated in the same way. As in the second exemplary embodiment of FIG. 2, the chamber 84 and therefore the counter pressure side 97 of the first diaphragm 61 in FIG. 3 experience the ambient pressure P AT , whereas the side 96' of the first diaphragm 61 experiences the delayed counter pressure P LV prevailing in the chamber 102 and communicated to it through the delay member 38. This pressure acts also upon the counter pressure side 104 of the second diaphragm 101, because the chamber 102 occupies the entire space between the two diaphragms 61 and 101 by reason of the openings 105 located in the intermediary wall 85' of a second housing 86'. The chamber 103 communicates with the intake manifold air line 29 through branch line 29b so that the entire manifold air pressure P L prevails in it and acts upon a primary pressure side 106 of the second diaphragm 101.
In this exemplary embodiment, the second diaphragm 101 must be larger than the first diaphragm 61, since, when the engine rpm is constant, and when the pressure in the chamber 103 is equal to the pressure in the chamber 102, only the smaller area of the diaphragm 61 is effective against the return force of the return springs 83; whereas during acceleration, the larger area of the diaphragm 101 is effective. The equalization spring 54, which is very weak and whose only purpose is to effect an abutment of a push rod 107 of the second diaphragm 101 to the setting member 63, is not opposed by a special return spring as is the case in the embodiment illustrated in FIG. 2. According to the embodiment of FIG. 3, springs 83 serve as the common return springs for both diaphragms 61 and 101. Of course, if the control characteristics require it, the second diaphragm 101 can be loaded directly by a return spring 53 as was done in the embodiment of FIG. 2.
The fourth exemplary embodiment depicted in FIG. 4 is constructed in a similar manner to that of the embodiment of FIG. 2 and those parts which are identical with the parts of FIG. 2, and whose operation is also the same, have been designated with the same reference numerals. The diaphragm 61 acting as the first movable partition and in the same way as in the second exemplary embodiment of FIG. 2, experiences the full manifold air pressure P L on its primary pressure side 96. The manifold air at pressure P L streams into the chamber 82 from the intake air line 29 through the connecting bore 28. The chamber 84, closed off by the counter pressure side 97 of the diaphragm 61, is acted upon by ambient air pressure P AT admitted through the bore 33 in the wall of the housing 10'. The connecting rod 63, which is fixedly attached to the membrane 61 and which serves as the setting member, abuts at its end 63a with a coaxial rod 108, which, in turn, is attached to a diaphragm 109 serving as a second movable partition. The diaphragm 109 has a primary pressure side 110 which experiences the full exhaust gas pressure P AB of the exhaust gases, which serve as a control medium and whose counter pressure side 111 experiences the exhaust gas counter pressure P AV , which builds up at a rate which is delayed by a delay member 38'. The delay member 38' is provided with a flow throttle 41' for effecting this purpose. The exhaust gas flows in through the exhaust gas line 113, and is led through a branch line 113a into a chamber 114, contiguous to the primary pressure side 110 of diaphragm 109. The full exhaust gas pressure P AB is effective in chamber 114, whereas as has already been mentioned, a delayed rising exhaust gas counter pressure P AV prevails in a chamber 112 and acts upon the counter pressure side 111 of the diaphragm 109. The supply channel to the chamber 112 is formed by a connecting bore 115 disposed in the wall of a housing section 116. The housing section 116 also includes the delay element 38' as well as tube connectors 117 for the exhaust gas lines 113 and 113a. The diaphragm 109, together with the push rod 108 and the surrounding chambers 112 and 114 is a fundamental component of the supplementary control unit 118 which is acted upon by exhaust gas serving as the control medium.
The fifth exemplary embodiment, shown in FIG. 5 in a simplified form, corresponds in its basic contruction to the first exemplary embodiment of FIG. 1, and identical parts are therefore identically designated. In order to eliminate the influence of the connecting rod 46 in FIG. 1 on the forces exerted by the manifold air pressure P L on the second movable partition 35, the second control unit 120 of the exemplary embodiment of FIG. 5 incorporates as a second movable partition two equally large coaxial, sequentially disposed diaphragms 121 and 122 which are attached to the two ends of a connecting rod 123. The connecting rod 123 is in turn pivotably connected via a lever 16 to a setting member 49. The setting member 49 can also be acted upon by the control unit 11. The primary pressure side 124 of the diaphragm 121 experiences the full intake air pressure P L prevailing in the intake manifold line 29 and admitted to a chamber 120a through a branch line 29b. The corresponding, equally large primary pressure side 125 of the other diaphragm 122, which serves as the counter pressure side of the second movable partition, is acted upon by a rising manifold air counter pressure P LV in the chamber 120b which is delayed by the delay member 38. The effect of a return spring 53 is to influence the operation of the second movable partition 121, 122 and the threshold response of the second control unit 120 can be adjusted by means of a compensating spring 54 as was done with the control unit 12 in FIG. 1. Two stops, 126 and 127, limit the stroke of the connecting rod 123 and therefore limit the position change (Δs) of the setting member 49 that can be produced by the second control unit 120. This second control unit 120 which is equipped with the two diaphragms 121 and 122 also has the advantage that the connecting rod 123 exerts no influence on the pressure surfaces and has the further advantage that the sleeves 128 and 129 for the rod 123 do not have to be specially sealed since in all the spaces surrounding these sleeves, ambient air pressure prevails.
The sixth exemplary embodiment, shown in FIG. 6 in a simplified form, is similar in construction to the fifth exemplary embodiment shown in FIG. 5. The second control unit 130 acts on a lever 16 and therefore also on a setting member 49, this action being in addition to that of a first control unit 11. The second movable partition consists of two diaphragms 131 and 132, both of which are attached to a connecting rod 133 which in turn is connected via the lever 16 with the setting member 49. In contrast to the example of FIG. 5, the primary pressure sides designated 137 and 134 of the two diaphragms 131 and 132 are opposed to each other, with the primary pressure side 134 being acted upon by the full manifold air pressure P L admitted through a manifold pressure line 29, and with the primary pressure side 137 being acted on by the manifold air counter pressure P LV , which is built up in a delayed manner by the member 38. The disposition of the diaphragms 131 and 132 according to FIG. 6 has the advantage over the disposition according to FIG. 5 of a constructionally more favorable placement at only one side of the lever 16, however, the guide sleeve 135 must be provided with a seal 136.
The seventh exemplary embodiment according to FIG. 7 employs a supplementary control unit 140 comprising two coaxial sequentially disposed and oppositely acting diaphragms 141 and 142 of different diameters. The diaphragms 141 and 142 are connected with one another by a rod 143, and are connected with the setting member 49 by a lever 144. The larger diaphragm 141 is exposed to the full manifold air pressure P L admitted through a manifold air line 29, while the smaller diaphragm 142 is exposed to the rising delayed counter pressure P LV , which is delayed by a delay member 38 so that during constant rpm operation of the engine, only the differential surface area of the two diaphragms 141 and 142 is effective. A chamber 145 surrounding the rod 143 and lying between the two diaphragms 141 and 142 contains air at ambient pressure P AT so that this construction contains no guide sleeve which must be sealed against a higher pressure.
OPERATION OF THE VARIOUS EMBODIMENTS
The method of operation of the control system according to the present invention is described below where, in particular, the method of operation of the supplementary control units 12, 98, 100, 118, 120, 130 and 140 is explained.
In FIG. 1, both control units 11 and 12 are shown in their quiescent position determined by the return springs 19 and 53 and the stops 34 and 40. The control unit 11 acts in a known manner as an intake manifold pressure dependent stop which includes a chamber 26 within which manifold air at a pressure P L is admitted through the manifold pressure line 29. During periods of increasing manifold air pressure P L the connecting rod 14 is displaced downwardly by the diaphragm 13 corresponding to the force acting on the diaphragm 13 and in opposition to the return spring 19. During this displacement the lever 16 pivots on the bolt 48 and at the same time moves the setting member 49 in the direction indicated by the arrow s. The setting member 49, in a known and therefore not more explicitly represented manner, either may actuate a full load stop for the supply quantity setting member of an injection system neither of which is shown, or it may displace the pivotal point of an intermediate lever belonging to a centrifugal rpm governor (also not shown) in such a way that the entire control region is displaced in the direction of increasing supply quantity.
The supplementary control unit 12 and its chamber 45, like chamber 26, are exposed to the full manifold air pressure P L through the branch line 29b; whereas the second chamber 43 is acted upon by a rising manifold air counter pressure P LV which is developed as a result of the flow throttle 41 in the delay member 38. Hence the supplementary control unit 12 acts as a pneumatic differentiating element or as a control unit with a delayed feedback. During, for example engine acceleration and therefore increasing manifold air pressure P L , a larger or smaller, depending on the magnitude of the acceleration, differential pressure Δ P (Δ P = P L - P LV ) acts upon the connecting rod 46 and displaces it downwardly. This causes the setting member 49 to be moved by the lever 16 also in the direction s beyond the position set by the first control unit 11 and in the direction of increasing supply quantity. The magnitude of the motion is designated in FIG. 1 by Δ s; with the second position of the setting member 49 being shown in broken lines.
Only during constant speed operation of the engine, i.e. when the rpm no longer changes, (n = const.), does the flow throttle 41 become ineffective and the same manifold air pressure P L prevails in the chamber 43 as well as in the chamber 45. Since no pressure difference Δ p is now present, the change of position Δ s which was produced by the secondary control unit 12 is restored to zero (Δ s =0), i.e. the connecting rod 46 and its diaphragm 35 return to their starting position, shown in FIG. 1. They are urged by the return spring 53 into their starting position in which position the diaphragm 35 abuts the cap stop 40. A stop 55, shown only schematically, limits the path of the rod 46 and therefore limits the maximum supplementary position change Δ s max provided for the setting member 49.
The design of the flow throttle 41 is such that during a slow intentional, operator controlled acceleration of the engine it is ineffective and therefore no effective differential pressure Δ p occurs at the supplementary control unit 12. The control unit 12 remains in the shown rest position and only the control unit 11, acting as a manifold pressure dependent stop is active.
By changing the throttle aperture of the flow throttle 41, and by changing the characteristics and pre-tension of the springs 53 and 54 as well as the adjustment of the stop 55 or perhaps by changing the surface area of the diaphragm 35, the supplementary control unit 12 can be adapted to produce any desired position change Δ s of the setting member 49.
In the second exemplary embodiment of FIG. 2, the supplementary control unit 98, as has been described above, is disposed at an extension of the axis of the connecting rod 63 and the force deriving from the differential pressure Δ P, which is transmitted from the diaphragm 62 to the connecting rod 64, just as was the case in the control unit 12 of FIG. 1, is added to the force which is exerted, in dependence on the manifold pressure P L , by the diaphragm 61 on the push rod 63 serving as a setting member. In this arrangement, the supplementary control unit 98 also becomes ineffective during constant rpm operation because the full manifold air pressure P L prevailing in the chamber 93 also builds up in the chamber 92 adjacent to the counter pressure side 91 of the diaphragm 62.
The check valve 89, disposed in the intermediate wall 85 of the housing section 86 permits equalization of the pressure between the chambers 92 and 82 during rapid pressure changes.
During constant speed operation or during very slow acceleration, no pressure difference Δ p exists across the membrane 62 and hence only the diaphragm 61 operates in dependence on the manifold pressure P L and, by means of angled lever 67, sets the full load stop 68 to the desired maximum fuel quantity to be provided. The set screw 81 limits the maximum possible adjustment path Δs max of the lever 67. This is necessary because the highest fuel supply quantity metered by the control system corresponding to the maximum manifold pressure must not be exceeded even when a more rapid acceleration is desired, because of the smoke restrictions placed on the engine. The excess fuel quantity metered by the supplementary control unit 98, and which is intended to permit a more rapid acceleration of the engine and also to compensate for the so-called lagging of the supercharger, is therefore effective only in that region which lies between the two limiting positions of the full load stop 68. These two limiting positions are set by the stops 95 and 81 and the setting region can also be shifted in a parallel sense by rotation of the set nut 78.
In the third exemplary embodiment according to FIG. 3, the supplementary control unit 100 contains a second diaphragm 101. This second diaphragm 101 must be larger than the first diaphragm 61, so that when the full manifold pressure P L is effective on the primary pressure side 106 of the second diaphragm 101 during acceleration of the engine the setting member 63 is moved downwardly via the push rod 107. When the pressure in the chamber 102, lying between the diaphragms 61 and 101, becomes equal to P L , that is, it equalizes with the pressure in the chamber 103, the larger diaphragm 101 is ineffective and the smaller diaphragm 61 acts alone. In this exemplary embodiment, in contrast to the exemplary embodiment according to FIG. 2, the pressure acting upon the primary pressure side 96' of the diaphragm 61 in the chamber 102 is continuously influenced by the flow throttle 41 of the delay element 38. Under certain operational conditions, this can be advantageous. If, however, the throttling effect is not desired, for example, during a deceleration of the engine, i.e. during a decrease of the manifold air pressure, then, similar to what was done in FIG. 2 between chambers 92 and 82, a check valve (not shown) can be inserted here in the connection between the manifold pressure line 29 and the chamber 102, making possible an undisturbed pressure decrease in the chamber 102.
The exemplary embodiment according to FIG. 4 shows the same basic construction as that according to FIG. 2; however, in this case, the control medium is the exhaust gas of the engine whose pressure increases more rapidly than does the manifold air pressure during an acceleration of the engine. For this reason the chambers 112 and 82 are separated from one another and manifold air streaming into the chamber 82 through the manifold pressure line 29 acts upon the diaphragm 61. The diaphragm 61 moves the setting member 63 in the same manner as was done in the exemplary embodiment according to FIG. 2. To this motion of the setting member 63, which is controlled by the diaphragm 61 and hence by the manifold air pressure P L , there is added the position change s produced by the supplementary control unit 118 when, during an acceleration of the engine, a differential pressure ΔP(ΔP=P AB - P AV ) acts on the side 110 of the diaphragm 109 in the chambers 114 and 112. This pressure difference urges the push rod 108 downwardly just as occurred in the previously described examples, and a supplementary position change of the setting member 63 is thereby effected.
In the previously described example according to FIG. 1, the surface area of the counter pressure side 37 of the diaphragm 35 which is acted upon by the control medium counter pressure P LV , is smaller than the surface area of the primary pressure side 36 of this same diaphragm which is acted upon by the full control pressure, the difference being equal to the cross section of the connecting rod 46. From this difference derives a delayed reponse threshold of the supplementary control unit 12 which is caused by the pre-tension Pv2 of the return spring 54. This influence of the connecting rod 46 is completely eliminated in the two exemplary embodiments according to FIGS. 5 and 6.
In the fifth exemplary embodiment according to FIG. 5, the full surface area of both the diaphragms 121 and 122 is effected at constant speed and since both diaphragms are of equal size, no differential force can occur. In other respects, the supplementary control unit 120 operates in the same way as the control unit 12 of FIG. 1.
In the sixth exemplary embodiment according to FIG. 6, the effect of the supplementary control unit 130 on the setting member 49 is the same as that described for FIGS. 5 and 1. Because the effective surface areas of the sides 137 and 134 of the two diaphragms 131 and 132, which are acted upon by manifold air pressure, are diminished by the same amount, i.e. by an area equal to the cross sectional area of the connecting rod 133, no net force due to unequal effective surface areas can develop. The differential pressure vanishes whenever, during constant speed operation, manifold air counter-pressure P LV acting on the side 137 of the diaphragm 131 has become equal to the manifold pressure P L acting on the side 134 of the membrane 132.
The exemplary embodiment according to FIG. 7 is designed so that during a rapid acceleration of the engine, the entire surface area of the larger diaphragm 141 is acted upon and, via the connecting rod 143 and lever 144, the setting member 49 is displaced for the provision of an increased fuel supply quantity. During constant speed operation or during a slow acceleration of the engine, the pressure exerted on the diaphragm 142 approximates that exerted on the diaphragm 141, and only the differential surface area of the two diaphragms 141 and 142 is effective for moving the setting member 49. This arrangement has the advantage that the construction is simple and neat, that there are no guiding sleeves to be sealed and that the cross sectional area of the connecting rod 143 has no influence on the forces acting upon the membranes 141 and 142.
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A fuel control system to provide an excess fuel quantity during engine acceleration and including manifold pressure actuated control units. The pressure increase in one control unit is delayed by throttling, resulting in net differential control forces tending to increase the fuel supplied to the injection nozzles of the engine injection system while the manifold pressure is rising.
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FIELD OF THE INVENTION
[0001] This invention relates generally to an electro-optical device and, more particularly, to a surface-emitting semiconductor laser.
BACKGROUND OF THE INVENTION
[0002] Conventional vertical cavity surface-emitting lasers (VCSELS) typically have two flat resonator cavity mirrors formed onto the two outer sides of a layered quantum-well gain structure, and are significantly limited in single spatial-mode output power, typically a few milliwatts. While greater optical power can be achieved from conventional VCSEL devices by using larger emitting areas, such a large aperture device is not particularly practical for commercial manufacture or use, and produces an output which is typically distributed across many higher order spatial modes. Several schemes have been proposed for increasing single-model output power from surface-emitting devices. One approach is to replace one of the mirrors adjacent the active region of a conventional VCSEL device with a more distant reflector whose curvature and spacing from the active region preferentially supports a fundamental spatial mode. Such a device architecture is called a VECSEL (vertical Extended cavity surface Emitting Laser).
[0003] “High single-transverse mode output from external-cavity surface emitting laser diodes”, M. A. Hadley, G. C. Wilson, K. Y. Lau and J. S. Smith, Applied Phys. Letters, Vol. 63, No. 12, 20 Sep. 1993, pp. 1607-1609, describes a triple-mirror, coupled-cavity device with an epitaxial p-type bottom Bragg mirror and undoped quantum-well gain structure grown on an external p-type substrate followed by an n-type coupled cavity intermediate mirror. The medium between the coupled cavity intermediate n-type mirror and the output coupler was air. Since any heat produced in the active gain region must be removed through the relatively thick p-type substrate, the practical output power from such a device is limited to about 100 mw for pulsed operation and to only a few mw for continuous (“cw”) operation.
[0004] “Angular filtering of spatial modes in a vertical-cavity surface-emitting laser by a Fabry-Perot étalon,” by Guoqiang Chen, James R. Leger and Anand Gopinath, Applied Physics Letters, Vol. 74 No. 8, Feb. 22, 1999, pp. 1069-1071, describes an integrated Fabry-Perot étalon formed of GaAs between a reduced bottom mirror stack of the VCSEL and a backside dielectric mirror, to thereby form an integrated coupled oscillator in which the angular plane-wave spectra of the higher-order modes have been spatially filtered out. No electrode configurations are shown or described and it is not apparent how that device could be electrically excited to produce high levels of output power.
[0005] My commonly assigned PCT publication WO 98/43329 describes a novel architecture for an electrically-excited vertical extended cavity surface emitting laser (VECSEL) device that enables the output power emitted in the single, lowest order TEM 00 spatial mode to be scaled upwards more than an order of magnitude beyond that achievable with other known VECSELS, while being much more practical and manufacturable than was previously achievable. In that device, the quantum-well gain layers were grown directly on the bottom surface of the n-type substrate; this growth was then followed by the usual highly-reflecting p-type DBR cavity mirror. The laser cavity was formed by depositing an anti-reflective coating on the top surface of the n-type substrate, and placing a concave external mirror away from the substrate with the mirror's optical axis oriented perpendicular to the plane of the substrate, such that the n-type substrate was located physically and optically within the laser cavity. Such an internal substrate configuration not only provides structural integrity and ease of manufacture (especially when the external mirror is formed on or otherwise placed directly on top of the inverted substrate), it also facilitates an electrode placement that is optimal for efficient electrical excitation and operation in the TEM 00 mode with a larger aperture and high output power levels than would otherwise be possible. However, especially in an electrically pumped device with a relatively thick substrate inside the laser cavity, increasing the doping of the substrate (desirable to minimize carrier crowding and electrical resistance) also increases the optical loss at the laser wavelength and the overall efficiency of the device is correspondingly reduced.
SUMMARY OF THE INVENTION
[0006] An overall objective of the present invention is to provide a surface emitting coupled cavity semiconductor laser device capable of producing one or more desired spatial modes at higher power levels and with greater device efficiency than would be feasible with known prior art VCSELs and VECSELs.
[0007] In accordance with the broader aspects of the present invention, an undoped gain region sandwiched between a nominally 100% reflective bottom Bragg mirror and an intermediate partially reflecting Bragg mirror is formed on a bottom lower surface of a supporting substrate, to thereby provide the first (“active”) resonator cavity of a high power coupled cavity surface emitting VECSEL laser device. The bottom mirror is preferably in direct thermal contact with an external heat sink for maximum heat removal effectiveness. The reflectivity of the intermediate mirror is kept low enough so that laser oscillation within the first active gain region will not will not occur without optical feedback from a second, passive resonator cavity, formed by the intermediate mirror and an external mirror contiguous to the upper surface of the VECSEL substrate. Thus, the substrate is entirely outside the first active resonator cavity but is contained within a second (“passive”) resonator cavity defined by the intermediate mirror and a partially reflecting output mirror. This second passive resonator cavity is directly coupled optically to the first active resonator cavity, and is designed to effectively increase the gain within the first active resonator cavity above the laser threshold, and/or to reduce the threshold for laser action in the first active resonator cavity, such that the output of the device is largely determined by the optical feedback from the second passive resonator cavity. Since the substrate is contained only in the second passive resonator cavity, and since the intermediate mirror forming this second passive resonator cavity typically has a transmissivity of only a few percent, the optical laser power in the second cavity is only a small fraction of the laser intensity circulating in the first active resonator cavity; therefore the substrate sees only a correspondingly small percentage of the light intensity energy that is circulating in the gain region. Thus any loss or other undesired effects caused by light intensity energy passing through the substrate are only that same small percentage that they would have been had that same substrate been placed in the same resonant cavity as the active gain region.
[0008] In a preferred embodiment, an electrically-excited coupled-cavity VECSEL electrically excited coupled cavity VCSEL utilizes an n-type semiconductor substrate with a partially reflective intermediate reflector (preferably an n-type Bragg mirror) grown on a bottom surface of the substrate. An undoped gain medium is grown or positioned under the intermediate reflector, and a bottom reflector is grown or positioned under the gain medium, to thereby form a first an active resonant cavity containing having an active gain region. The bottom reflector is preferably a p-type Bragg mirror having a reflectivity of almost 100%, which is soldered to or otherwise placed in thermal contact with an external heat sink. A second passive resonator cavity is formed by the partially-transmitting intermediate cavity mirror grown on the bottom surface of the n-type substrate, and a partially-transmitting output cavity mirror, positioned externally above the upper surface of the substrate. The output mirror is positioned above the substrate at the opposite side of the p-type Bragg mirror and defines a passive resonant cavity. This second passive resonator cavity is designed to control the spatial and frequency characteristics of the optical feedback to, and thus the laser oscillation within, the first active resonant cavity. It in effect functions as a spatial filter, with the external output cavity mirror preferably configured (curvature, reflectivity, and distance from the intermediate reflector) to limit the laser to confine the resonant radiation within the second passive resonator cavity to a single fundamental mode; since the mode of any laser output from the first active resonator cavity is determined by the mode of the feedback from the second passive resonator cavity, the output spatial mode from the overall device is essentially confined to that single fundamental mode.
[0009] Such a novel VECSEL structure is particularly advantageous when the electrical current is applied to an external electrode and must pass through a conductive substrate in order to reach the active gain region. Since the active gain region is in a first one cavity and the conductive substrate is in second another cavity, the substrate can have a substantially higher doping level and/or a substantially associated lower electrical resistance than would otherwise be possible. The electrode configuration is preferably similar to that described in my referenced International patent publication, with the disk shaped bottom electrode formed by an oxide current aperture between the bottom mirror and the heat sink and with the annular top electrode formed on the top surface of the substrate (above or surrounding the AR coating), to thereby define a cylindrical electrically excited primary gain region surrounded by an annular secondary gain region.
[0010] In accordance with the method aspects of the present invention, the first active resonant cavity is epitaxially grown on the bottom surface of the substrate. The top surface of the substrate is provided with an anti-reflective coating and an external output mirror configured to control the desired mode or modes of the laser energy resonating both in the second passive resonant passive and in the first active cavity. In the preferred embodiment the external mirror is separated from the substrate and is configured to provide the desired fundamental mode output. In an alternative embodiment that takes particular advantage of the coupled-cavity configuration to reduce losses within the second passive cavity, the substrate may occupy the full extent of the second passive cavity and its top surface may be configured by binary optics techniques prior to depositing the required upper electrode and top reflector, to thereby produce monolithic fully integrated coupled cavity device.
[0011] Optionally a non-linear frequency doubling material may be included inside the second passive resonant cavity to thereby convert or reduce the output wavelength from the longer. Wavelengths associated with typical semiconductor laser materials, such as GaAs and GaInAs, to the shorter wavelengths necessary or desirable for various medical, materials processing, and display applications. In that case, the reflectivity characteristics of the various optical components are preferably chosen to favor the feedback of the unconverted fundamental wavelength back towards the active gain region and the output of any already converted harmonics through the output mirror.
[0012] As another option, a polarizing element which selectively favors a desired polarization orientation may be included within the second passive resonant cavity. Such a polarizing element may be in the form of a two-dimensional grid of conductive lines located at an anti-node of the optical energy resonating within the second passive resonant cavity to thereby absorb polarization parallel to those lines, and may be conveniently formed on the upper surface of the substrate adjacent to the anti-reflection layer.
[0013] Alternatively a saturable absorber or other suitable mode-locking means may be included within the second passive resonator cavity to provide a high peak power output pulse.
[0014] In yet another optional embodiment, the second passive resonator cavity is integrated with one end of a single mode optical fiber by means of a focusing lens element and the reflector defining the upper end of the second passive resonant cavity is in the form of a distributed Bragg reflector formed by longitudinal variations in the refractive index of the fiber.
[0015] A plurality of coupled cavity vertical extended cavity surface emitting lasers (VECSELS) devices having different modes and/or frequencies may be fabricated in one- or two-dimensional arrays, to thereby provide a wideband transmission source for multimode optical fiber transmission systems and/or to provide a 3-color light source for a projection display. Alternatively the individual devices of such an array may be operated coherently by means of a shared passive external resonator cavity to provide a coherent single mode output having an even higher power than would otherwise be possible. Such a device would use, for example, a spatial filter in the passive cavity to force all elements of the array to emit in phase.
[0016] An additional advantage of a coupled cavity device constructed in accordance with the present invention is that the output laser wavelength is determined by the Fabry-Perot resonance frequency of the active cavity. This wavelength tunes with temperature at the rate of about 0.07 nm per degree centigrade for GaInAs type devices operating in the 980 nm wavelength region, thereby providing a convenient tuning mechanism for certain applications requiring a variable wavelength tunable output, in discrete jumps essentially corresponding to the possible resonances within the second passive cavity.
[0017] Although the hereinafter-described preferred embodiment utilizes electrical excitation and an n-type doped substrate, many aspects of the invention are also applicable to optical or e-beam excitation, and to the use of n-type materials for the Bragg mirrors at both ends of the first active resonator cavity, with one or more Esaki diodes placed at resonant nodes inside the first active resonator cavity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The foregoing and other objects, features and advantages of the invention will be apparent from the more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.
[0019] FIG. 1 is a longitudinal cross section of a vertical coupled cavity high power semiconductor laser according to the present invention, with an external output mirror and an optional mode control region between the substrate and the output mirror.
[0020] FIG. 2 is a longitudinal cross section of an alternative embodiment of the present invention, with a integrated output mirror formed directly on the upper surface of the substrate.
[0021] FIG. 3 is an output power curve showing pulsed output power for a preferred embodiment as a function of current.
[0022] FIG. 4 shows a polarizing element which may be included within the mode control region.
DETAILED DESCRIPTION OF THE INVENTION
[0023] A preferred embodiment of a coupled cavity VECSEL 10 according to the present invention is shown schematically in FIG. 1 . The coupled cavity VECSEL 10 includes an n-type semiconductor substrate 12 . The substrate 12 of the present invention should be sufficiently thick to be conveniently handled during manufacturing process and is sufficiently doped with n-type dopants to reduce the electrical resistance of substrate 12 to a value required for efficient operation and nearly uniform carrier injection across the current aperture region at high power levels (so that the active gain region is pumping uniformly without excessive carrier crowding), but without a corresponding sacrifice of the optical efficiency, as will be explained in detail in the following paragraphs. In an exemplary embodiment, the current aperture diameter is 100 μm and the doping level of the n-type dopants in the substrate is approximately between 1×10 −17 cm −3 and 5×10 −17 cm −3 ; the substrate is approximately 50 μm to 350 μm thick.
[0024] An intermediate reflector 14 is formed on a first (as illustrated, the bottom) surface of the n-type substrate 12 . The intermediate reflector 14 may be epitaxially grown on the substrate 12 or it may be positioned on substrate 12 by various techniques well known in the semiconductor art. In an exemplary embodiment, intermediate mirror 14 is an n-type Bragg reflector built up of 12 to 15 pairs of GaAs/AlAs wells doped with n-type dopants, such as silicon or tellurium, at a concentration of approximately 2×10 −18 cm −3 and can be grown by using the MOCVD or MBE growth that are well know in the art, to thereby produce a reflectivity of about 95%. A typical reflectivity range would be from 80-98%, although it could vary from near zero to more than 99%, depending on the specific application. In general, it should be as high as possible without permitting sufficient gain to occur in the first active resonator cavity to produce stimulated emission without any feedback from the second passive resonator cavity. However, in certain applications in which a non-linear frequency doubler or other mode control element is contained in the second passive resonator cavity, the reflectivity of the intermediate reflector 14 is preferably reduced to a value sufficient to ensure that the power contained in the passive cavity is adequate for efficient frequency conversion.
[0025] A gain-region 16 is epitaxially grown or positioned on the lower surface (the side facing away from substrate 12 ) of the intermediate reflector 14 . The gain region 16 is made of multiple-quantum-well III-V compound materials, such as GaInAs, that are well-known in the art. In general, the more quantum wells in the gain region 16 the higher the single pass stimulated gain of the VECSEL will be. However, strain compensation in the gain region 16 containing GaInAs wells may be required for more than three quantum wells to avoid excessive strain that will potentially generate crosshatch or fracture defects during manufacturing.
[0026] A p-type Bragg mirror 18 is epitaxially grown or positioned on the gain region 16 at the opposite side to the substrate 12 . Preferably, the p-type Bragg mirror 18 has a reflectivity of approximately 99.9% and is formed by approximately 18 to 30 pairs of quarter wave stacks of GaAs/AlAs layers doped with p-type dopants, such as zinc, carbon or Be, at a concentration of approximately 2-3×10 18 cm −3 . The p-type Bragg mirror 18 may be epitaxially grown by using the MOCVD or MBE techniques well known in the art. In an alternative embodiment, the p-type Bragg mirror 18 can also be spatially doped in a narrow region at the interfaces with carbon at a concentration of approximately 1×10 19 cm −3 to reduce the electrical impedance of the p-type Bragg mirror 18 by reducing the effects of localized heterostructure junctions at the quarter wave interfaces within the p-type Bragg mirror 18 .
[0027] Intermediate reflector 14 , gain region 16 and bottom reflector 18 cooperate to define an active cavity having a cavity length l at the wavelength of interest (this wavelength is determined by the Fabry-Perot resonance frequency of the first active resonator cavity and in the absence of a non-linear frequency doubler in the second passive resonator cavity, will be the output wavelength of the device). Since this wavelength tunes with temperature at the rate of about 0.08 nm per degree centigrade for GaInAs type devices operating in the 980 nm wavelength 20 region, a heat sink 20 or other suitable temperature control means is provided which is in thermal contact with the lower surface of the relatively conductive p-type Bragg mirror 18 . In the preferred embodiment, the heat sink 20 is formed of beryllia or diamond and includes a conductive electrode 20 A. An oxide aperture defining layer 22 is preferably provided between the p-type Bragg mirror 18 and the heat sink 20 , which has a generally circular current limiting aperture 22 A though which the excitation current I, required to operate the device is confined.
[0028] The upper surface of the GaAs wafer 12 is preferably anti-reflection coated with a conventional AR layer 24 , but may be left uncoated (nominal 30% reflectivity). Additionally, in yet another embodiment, the first surface of the substrate 12 may be coated with anti-reflection coating to improve efficiency of the VCSEL. For example, the substrate 12 may be coated to be anti-reflection at a fundamental wavelength and be highly reflective at a second harmonic wavelength of the optical emission.
[0029] An annular electrode 26 similar to that disclosed in my previously identified International patent publication is formed on the upper surface of substrate 12 . The top electrode could cover the entire top surface of the chip with a circular aperture for the laser beam. Its central aperture 26 A is preferably substantially larger than the effective diameter of lower electrode 22 A, to effectively eliminate any loss due to aperturing of the laser mode. In particular, as described in further detail in that publication (which is hereby incorporated in its entirety by reference), the diameter of the bottom electrode 22 A corresponds to the electrically pumped region D 1 within the active cavity l and the inner diameter of the upper electrode 26 corresponds to the outer diameter D 2 of an optically pumped annular region extending laterally outwards from region D 1 .
[0030] An output mirror 28 is positioned externally and approximately parallel to the substrate 12 in the preferred embodiment, as shown in FIG. 1 . The output mirror 28 has a reflectivity in the range of approximately 40%-80%. The external output mirror 28 may be a dielectric mirror.
[0031] In an alternative embodiment, a nonlinear material 30 may be positioned inside the passive resonant cavity L defined by the output mirror 28 and the intermediate mirror 14 . The nonlinear material 30 may be external to the substrate 12 or it maybe monolithically positioned directly on the substrate 12 . The nonlinear material 30 is used in an otherwise conventional manner to convert a substantial portion of the resonant energy to a higher (typically a first harmonic) frequency, with the spectral response of the output mirror being substantially more transmissive for the higher frequency. Suitable nonlinear materials include KTP, KTN, KNbO 3 , or LiNbO 3 and periodically-poled materials such as periodically-poled LiNbO 3 .
[0032] Since the optical emission intensity within the nonlinear material 30 has to be sufficiently high in order to have an efficient nonlinear conversion, by the nonlinear material 30 , the reflectivity of the intermediate reflector 14 may be lower and the gain of the active region 16 may be higher (for example, by the use of more quantum wells) than what would otherwise be optimal for output at the fundamental frequency of the active cavity l. Alternatively, the optical emission intensity of both resonant cavities l, L and thus the frequency conversion efficiency of the device could be increased by means of an RF driven injection current that would produce a mode-locked operation of the device operating at a repetition frequency equal to the cavity round trip frequency or harmonics of it. This would produce short optical pulses with peak power levels as much as 100 times that of a cw device.
[0033] To further increase the efficiency of the nonlinear conversion, the transmissivity of the intermediate reflector 14 and or/of the AR coating 24 is preferably made substantially higher for the fundamental frequency than for the higher frequency harmonics, thereby selectively feeding back only the fundamental frequency into the active cavity l.
[0034] In another alternative embodiment, the output mirror 28 may be formed directly on the substrate 26 , as shown in FIG. 2 . In the alternative embodiment, the output mirror 28 may be formed by a dielectric mirror or by an n-type Bragg mirror having a reflectivity in the above-mentioned range. For the n-type Bragg output mirror in the alternative embodiment, the output mirror 28 is monolithically grown on a first surface of the substrate 12 . Prior to the growth of the output mirror 28 , the first surface of the substrate 12 is etched by otherwise conventional binary optics etching techniques to form an appropriately shaped surface. Alternatively, a dielectric mirror can be deposited on the etched surface that would form a concave mirror output coupler.
[0035] The optical emission that passes the intermediate reflector 14 and into the substrate 12 would effectively see significantly less optical loss than it would have been without the intermediate reflector 14 . The doping density and the thickness of the substrate 12 normally dominate the optical loss of the VCSEL due to the free carrier absorption effect in the substrate 12 . As noted, there is a design trade-off between the thickness, electrical resistance, and optical loss of the substrates of conventional VCSELs for optimum device performance. Generally, the higher the doping. Level of the substrate or the thicker the substrate, the bigger the optical loss of the VCSELS will be. Consequently, substrates of conventional VCSELS tend to have high doping levels to reduce the impedance and to have thin substrates to reduce the optical loss. In contrast, the present invention limits the amount of optical emission, approximately 5% of the optical emission, entering the substrate 12 before it reaches the lasing threshold, thereby reducing the overall optical loss of the VCSEL 10 . As a result, by having an intermediate reflector 14 , the present invention can further increase the doping level of the substrate 12 for a low impedance and/or utilize a thicker substrate 12 for better handling during manufacturing of the VECSEL 10 , while at the same time greatly increasing the overall efficiency of the VCSEL 10 . In general, the thickness of the substrate 12 according to the present invention ranges from about 50 μm to 350 μm that would allow the VCSELS to be handled rather easily for mass production. Moreover, the high doping concentration in the substrate 12 produces additional benefits of a near uniform injected carrier distribution across the aperture region surrounded by the oxide aperture 22 , even at very high current densities.
[0036] In the present invention, much of the optical energy emission originating in the gain region 16 will be confined inside the gain region 16 due to high the reflectivities (for example 95% and 99.9% respectively) of the intermediate reflector 14 and the p-type Bragg mirror 18 and will resonate therein until the optical emission reaches the threshold lasing level. Since the substrate is contained only in the second passive resonator cavity and the exemplary intermediate mirror has a transmissivity of only a few percent, the energy level in the second passive resonator cavity is only a few percent of the energy level in the first cavity and the substrate sees significantly less of the light energy that is circulating in the gain region. Thus any loss or other undesired effects caused by light energy passing through the substrate are only a few percent of what they would have been had that same substrate been in the same resonant cavity as the active gain region, and the overall efficiency of the device have been increased by as much as 10 to 20 fold.
[0037] Thus, the coupled cavity design according to the present invention is capable of generating a very high emission power. For example, more than one watt has been produced in a TEM 00 mode at wavelengths of about 960-980 nm, with injection current diameters ranging from 75 to 250 μm, and intermediate reflector reflectivity of about 90% to 95% and output mirror reflectivity of about 20% to 90%. However, optimum output power is generally achieved by using an output mirror 28 having a reflectivity ranging between 40% and 60% and with the Fabry-Perot wavelength of the active cavity kept close to that of the desired emission peak, for example by careful control of active cavity length l during the growth process. In this case, the surface of the substrate was anti-reflection coated.
[0038] FIG. 3 shows a polarizing element 32 which selectively favors a desired polarization orientation. AS illustrated it is in the form of a two-dimensional grid of conductive lines and is located at an anti-node of the optical energy resonating within the second passive resonant cavity to thereby preferentially absorb polarization parallel to those lines. In an exemplary embodiment, it may be conveniently formed on the upper surface of the substrate 12 adjacent to the anti-reflection layer 24 . Since polarizing element 32 is inside 25 the second (passive) cavity, higher losses in the favored polarization direction can be tolerated than would be the case for a single cavity device.
[0039] Referring specifically to FIG. 3 , a 100-micron current aperture coupled cavity device operating in pulsed power mode has been observed to produce a circular TEM 00 mode at 963 nm with an output power as a function of current is that is essentially kink-free up to the full power level. The slight change just above one ampere corresponds to a scale change in the power supply. The change in slope efficiency is likely due to transient heating that shifts the gain peak away from coupled cavity Fabry-Perot wavelength, since the device under test was not soldered to a heat sink and likely experienced an increase in temperature during the injection current pulse. Additionally the design of the test device did not take into account the presence of any lateral stimulated optical emission in the plane of the device structure that would direct energy out of the mode region, and would be even more efficient (and the power curve would be more linear) at higher power levels if designed to incorporate the teachings of my referenced International patent publication. since the dominant wavelength inside the active resonant cavity 16 tunes with temperature at the rate of about 0.07 nm per degree centigrade for GaInAs type devices operating in the 980 nm wavelength region, changes in temperature (for example, by selective adjustment of current density) provide a convenient tuning mechanism for certain applications requiring a wavelength corresponding to one or more of the possible resonances within the passive resonant cavity. Alternatively, it may be desirable to apply a small dither to the excitation current I to force partition (sharing of power) over several longitudinal modes. For example, by providing a relatively long passive cavity L, the supported modes will be more than 20 GHz apart and the effects of stimulated Brillouin scattering in single-mode optical fibers can be substantially reduced by varying the power and therefor the temperature of the active gain region. In that case, the frequency of dither should be substantially faster than the time it takes for backward SBS wave to build up, with higher dither frequencies being required for higher levels of laser power in the fiber.
[0040] Even higher levels of output power may be achieved by means of an array of VECSELS constructed in accordance with the preset invention. Power levels of more than 10 watts can be achieved from such array approaches.
[0041] A plurality of the above-described VECSEL elements 10 fabricated on a single semiconductor substrate 12 may be made to oscillate together incoherently by driving them in parallel from a common source of electrical or optical energy, to thereby provide a higher output power than would be possible from a single VECSEL device. Alternatively, the individual VECSELS may be driven optically in serail fashion, with some or all of the output from one element driving the next. In either case, each of the individual coupled cavity laser elements can have a structure and a mode of operation substantially identical to that described previously. The output beams from the individual elements will all travel effectively in the same direction and can be focused by a single lens to one point.
[0042] It is also possible to fabricate an array of the above-described coupled cavity VECSELS such that the all elements of the array operate coherently with respect to one-another. This can be achieved in either of two ways. In the first, similar to what has been described in my U.S. Pat. No. 5,131,002 for a set of non-coupled cavity emitting elements (which is hereby incorporated by reference) all of the optical elements are connected in series to add the optical laser power from each element, but the elements are separated to spear the thermal load. Alternatively, all elements of the array may be made to oscillate coherently with respect to one another by a single common external cavity with the light output from all the elements focused at an output coupler, by means of a spatial filter that rejects light in those regions which would have no light present if all elements of the array were oscillating coherently together as a result of destructive interference. Such a “spatial filter” based on destructive interference is described by Rutz in U.S. Pat. No. 4,246,548 (which is also incorporated by reference). However, when applying Rutz' spatial filter to an array of coupled cavity VECSELS, it is important that the frequencies of all of the emitting elements lie close to each other. Each frequency is defined by the length of the short active cavity, while the bandwidth of the allowed frequencies is related to the magnitude of the mirror reflectivity values. This requires that the temperature variation across the array must be controlled to better than a degree. It is also important that the growth tolerance of the wafer is to be such that a corresponding level of accuracy is maintained, which is not particularly difficult with present epitaxial growth technology.
[0043] From the foregoing, it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made by persons skilled in the art without deviating from the spirit and/or scope of the invention. Specifically, the VECSEL according to the present invention is capable of producing high power output. However, the present invention may be readily adapted to various low power applications by appropriate adjustments of both the effective diameter of the gain region and the injection current level, so as to provide an optimal current density in the active gain region for laser operation. The dimensions and doping levels of various regions of the devices may also be modified to accomplished optimum performance for various applications. The reflectivities of the intermediate reflector 14 , the p-type Bragg mirror 18 , and the output mirror 28 may also be adjusted to accomplish optimum performance results.
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An active gain region sandwiched between a 100% reflective bottom Bragg mirror and an intermediate partially reflecting Bragg mirror is formed on a lower surface of a supporting substrate, to thereby provide the first (“active”) resonator cavity of a high power coupled cavity surface emitting laser device. The bottom mirror is preferably in direct thermal contact with an external heat sink for maximum heat removal effectiveness. The reflectivity of the intermediate mirror is kept low enough so that laser oscillation within the active gain region will not occur. The substrate is entirely outside the active cavity but is contained within a second (“passive”) resonator cavity defined by the intermediate mirror and a partially reflecting output mirror, where it is subjected to only a fraction of the light intensity that is circulating in the gain region. The active gain region is preferably electrically excited, with a circular bottom electrode formed by an oxide current aperture between the bottom mirror and the heat sink, and with an annular top electrode formed on an upper surface of the substrate.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and apparatus for reproducing data from a signal read out from a recording medium or transferred by a communication means and, more particularly, to a method and apparatus for reproducing data subjected to convolution based on partial response, by using maximum likelihood.
2. Related Background Art
In recent years, high-density information recording or information transfer at a high transfer rate has become popular for a data reproducing apparatus. For example, a signal processing method called PRML is known as a means for realizing such high-density recording or high transfer rate. The PRML signal processing method uses a combination of PR (Partial Response) and ML (Maximum Likelihood). Partial response is a technique of reproducing data by waveform equalization. A signal read out from a recording medium or transferred by a communication means is output while its waveform is distorted by intercode interference. To properly reproduce data from this signal, the noise component may be removed by filtering. However, the frequency band of the noise component overlaps that of the data signal component over a wide range in fact, and it is therefore difficult to remove the noise component. In partial response, data convolution is performed on the basis of predetermined rules to narrow the band of the data signal, thereby performing data reproduction with a high S/N ratio. The use of partial response allows high-density signal recording in a recording medium and also can cope with an increase in influence of intercode interference on the signal read out from the medium, so that the capacity of information recordable in the recording medium can be increased.
Several schemes are known as partial response, and the above scheme is normally expressed as “PR(1,1)”. “PR” is the initials of “partial response”. The first “1” in the parentheses represents the original signal, and the second “1” represents that a signal delayed by one bit is superposed on the original signal. Assume a binary signal “010100101100”, as shown in FIG. 14A. A signal shown in FIG. 14B, which is delayed by one bit, is superposed on the binary signal, thereby obtaining a signal shown in FIG. 14 C. The signal shown in FIG. 14C is called a signal obtained upon waveform equalization by PR(1,1). This signal is a ternary signal with signal amplitude levels “1”, “0”, and “−1”. The signal shown in FIG. 14C has a frequency band narrower than that of the original signal.
Similarly, PR(1,2,1) represents that a signal (FIG. 15B) obtained by delaying a binary signal as shown in FIG. 15A by one bit and doubling its amplitude and a signal (FIG. 15D) obtained by delaying the signal (FIG. 15A) by two bits but with the same amplitude as that of the original signal (FIG. 15A) are superposed on the original binary signal. Consequently, a signal shown in FIG. 15D is obtained. The signal shown in FIG. 15D is called a signal obtained upon waveform equalization by PR(1,2,1). This signal is a quinary signal with signal amplitude levels “2”, “1”, “0”, “−1”, and “−2”. The signal shown in FIG. 15D has a frequency band narrower than that of the original signal. It can be regarded in PR(1,2,1) that signals obtained upon waveform equalization by PR(1,1) are shifted from each other by one bit, and convolution is further performed.
Maximum likelihood is a technique used when data is to be detected in accordance with information convolution by the above-described partial response. Data with the highest probability is selected to determine the data.
For a signal obtained upon waveform equalization by partial response, a value at a certain time point contains previous information, e.g., information two bits before in PR (1,2,1). For this reason, the original data cannot be determined on the basis of only that value. When maximum likelihood is performed, the data can be properly reproduced from the signal obtained by partial response.
As a specific technique of realizing such maximum likelihood, a matrix method is proposed in, e.g., “A Reliable Signal Detection Method for the Combination of PRML Method and Ternary Recording Code”, S. Tazaki, et. al., Proc. '94 IEEE ISIT, p. 214 (June, 1994). The present inventors have filed on an information recording/reproducing apparatus which employs partial response PR(1,1) and reproduces binary digital information by maximum likelihood, which is disclosed in Japanese Patent Application No. 6-181363.
In the former technique, however, a large usable memory must be ensured, and the calculation time is long. In the latter apparatus, detection data is input to a shift register array, and signal processing performed. Data “1” and “0” stored in the shift register correspond to the number of states, so this apparatus can hardly cope with four or more states.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a data reproducing method and apparatus capable of solving the above problems and performing maximum likelihood with a small memory capacity even when the number of states is large.
In order to achieve the above object, according to the present invention, there is provided a data reproducing apparatus for reproducing data subjected to convolution by partial response, by using maximum likelihood, wherein the data reproducing apparatus comprises memory means including a plurality of memory arrays which respectively correspond to plural states that the data can take and each of which has a predetermined number of regions each corresponding to a time point, detection means for periodically detecting, from the data, states before the plural states have been shifted, and control means for causing values respectively representing the detected states before shifting to be sequentially stored in said regions of said memory arrays every time detection is performed by said detection means, causing the values previously stored in said memory arrays to be replaced in accordance with the detected states before shifting, and when all values stored in said regions of said memory arrays corresponding to the same time point match, reproducing the data on the basis of the matching value.
According to the invention, there is provided a method of reproducing data subjected to convolution by partial response, by using maximum likelihood, in a data reproducing apparatus comprising memory means including a plurality of memory arrays which respectively correspond to plural states that the data can take and each of which has a predetermined number of regions each corresponding to a time point, and detection means for periodically detecting, from the data, states before the plural states have been shifted, wherein the data reproducing method comprises the steps of:
periodically detecting, from the data, the states before the plural states have been shifted by using said detection means;
sequentially storing a value representing the detected state before shifting in each region of said each memory array every time detection is performed by said detection means;
replacing values previously stored in said memory arrays, in accordance with the detected states before shifting; and
when all values stored in said regions of said memory arrays corresponding to the same time point match, reproducing the data on the basis of the matching value.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing a data reproducing apparatus according to an embodiment of the present invention;
FIG. 2 is a chart showing the waveform of a reproduction signal obtained upon waveform equalization by PR(1,2,1);
FIG. 3 is a state diagram showing state transition observed when waveform equalization by PR(1,2,1) is performed;
FIG. 4 is a graph showing a distribution of the reproduction signal at data identification points, which is observed when waveform equalization by PR(1,2,1) is performed;
FIG. 5 is a circuit diagram showing an arrangement of the binarizing circuit of the apparatus shown in FIG. 1;
FIG. 6 is a trellis diagram showing an example of state transition of the reproduction signal;
FIGS. 7A to 7 E are views for explaining the operation principle of reproduction/decoding when the states change as shown in FIG. 6 in the apparatus shown in FIG. 1;
FIG. 8 is a circuit diagram showing an arrangement of the maximum likelihood circuit of the apparatus shown in FIG. 1;
FIG. 9 is a circuit diagram showing an arrangement of a 2-bit memory used in the maximum likelihood circuit shown in FIG. 8;
FIG. 10 is a circuit diagram showing an arrangement of a select circuit used in the maximum likelihood circuit shown in FIG. 1;
FIG. 11 is a circuit diagram showing another arrangement of the binarizing circuit of the apparatus shown in FIG. 1;
FIG. 12 is a circuit diagram showing another arrangement of the maximum likelihood circuit of the apparatus shown in FIG. 1;
FIG. 13 is a circuit diagram showing an arrangement of a select circuit used in the maximum likelihood circuit shown in FIG. 12;
FIGS. 14A to 14 C are views for explaining waveform equalization by PR(1,1); and
FIGS. 15A to 15 D are views for explaining waveform equalization by PR(1,2,1).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a data reproducing apparatus according to an embodiment of the present invention. Referring to FIG. 1, a reproduction signal 1 is read out from a recording medium (not shown) such as an optical disk, which is a reproduction signal obtained upon waveform equalization by partial response. In this embodiment, partial response PR(1,2,1) is employed. A binarizing circuit 2 detects the level of the reproduction signal 1 and outputs state transition. A maximum likelihood circuit 3 receives an output signal from the binarizing circuit 2 , performs maximum likelihood, and outputs reproduction data 4 . The maximum likelihood circuit 3 is constituted by a memory 5 and a control circuit 6 . The arrangements and operations of the binarizing circuit 2 and the maximum likelihood circuit 3 will be described later in detail.
FIG. 2 is a chart showing the waveform of the reproduction signal 1 shown in FIG. 1, i.e., a reproduction signal read out from the recording medium and subjected to waveform equalization by partial response. Referring to FIG. 2, the reproduction signal 1 is divided into five values at a data identification point (time: 0.0) by performing information convolution based on waveform equalization by partial response. More specifically, the reproduction signal is divided into five values “−2”, “−1”, “0”, “1”, and “2” from the lower amplitude level side. V th1 to V th4 represent comparison levels for detecting the state transition of the reproduction signal by the binarizing circuit 2 as will be described later. In this embodiment, partial response PR(1,2,1) is employed, as described above. When information convolution is performed by imparting intercode interference by partial response, the reproduction signal as shown in FIG. 2 is obtained. A description of partial response PR(1,2,1) has been made above with reference to FIGS. 15A to 15 D.
FIG. 3 is a state transition diagram showing state transition of the reproduction signal shown in FIG. 2 in a trellis. In FIG. 3, S 0 to S 3 represent the states of the reproduction signal. For example, the state S 0 follows the state S 0 or the state S 2 , as indicated by arrows. A change from the state S 0 to the state S 0 is represented by −2/000 in which “−2” represents the detection level at the data identification point shown in FIG. 2, and “000” represents the reproduction data candidate at that time.
In a change from the state S 2 to the state S 0 as well, “−1” of −1/100 represents the detection level at the data identification point, and “100” represents the reproduction data candidate. The state S 1 results from the state S 0 or the state S 2 , the state S 2 results from the state S 1 or the state S 3 , and the state S 3 results from the state S 1 or the state S 3 , as indicated by arrows. In any case, an arrow represents the direction of state transition together with the detection levels at the data identification point and the reproduction data candidate at that point.
The number of states is determined depending on the manner of convolution by partial response. For example, in PR(1,2,1), convolution of information two bits before is made, so that the number of states is 2×2=4. When convolution of information n bits before is made, the number of states is 2 n .
FIG. 4 is a graph showing the reproduction signal amplitude distribution at the data identification point shown in FIG. 2 . As is apparent from FIG. 4, the reproduction signal amplitude distribution is a Gaussian distribution having peaks at amplitude levels “−2”, “−1”, “0”, “1”, and “2”. The width of the Gaussian distribution can be considered to be determined by the S/N ratio of the reproduction signal. As for state transition from a certain time point to the next time point, which has been described above with reference to FIG. 3, transition with a high probability is selected in accordance with the Gaussian distribution shown in FIG. 4 . In maximum likelihood, a reproduction data string with the highest probability is selected by selecting state transition, thereby reproducing data.
FIG. 5 is a circuit diagram showing an arrangement of the binarizing circuit 2 in detail. The binarizing circuit 2 comprises four comparators 14 to 17 . Each comparator compares the reproduction signal 1 with a predetermined comparison level, and outputs the comparison result. The reproduction signal 1 is a reproduction signal obtained upon waveform equalization, as described above. The comparison level V th1 is input to the comparator 14 , the comparison level V th2 is input to the comparator 15 , the comparison level V th3 is input to the comparator 16 , and the comparison level V th4 is input to the comparator 17 . Each comparator compares the reproduction signal with the comparison level and outputs the comparison result to the maximum likelihood circuit 3 . The comparison levels V th1 to V th4 correspond to those shown in FIGS. 2 and 4.
The comparator 14 compares the reproduction signal with the comparison level V th1 in FIG. 2 at the data identification point and outputs the comparison result. In this case, when the amplitude level of the reproduction signal at the data identification point is higher than the comparison level V th1 , there is a high probability that the amplitude level of the reproduction signal at the data identification point is “−1” rather than “−2”, as is apparent from FIG. 4 . To the contrary, when the amplitude level of the reproduction signal at the data identification point is lower than the comparison level V th1 , there is a high probability that the amplitude level of the reproduction signal at the data identification point is “−2” rather than “−1”.
This difference corresponds to determination of state transition described above with reference to the state diagram of FIG. 3, i.e., whether the state before the state S 0 is the state S 0 or the state S 2 . More specifically, the comparator 14 compares the reproduction signal with the comparison level V th1 as shown in FIG. 2 to detect the level of the reproduction signal at the data identification point and outputs data representing the state before the state S 0 , i.e., the state S 0 or the state S 2 . In this manner, the comparator 14 detects the level of the reproduction signal, detects the state transition on the basis of the level of the reproduction signal, and outputs the detection result from its output terminal and ground line to the maximum likelihood circuit 3 as an output 10 , i.e., 2-bit data “00” or “10”.
The comparator 15 compares the reproduction signal with the comparison level V th2 in FIG. 2 and outputs the comparison result. In this case as well, as in the above description, when the amplitude level of the reproduction signal at the data identification point is higher than the comparison level V th2 , there is a high probability that the amplitude level of the reproduction signal at the data identification point is “0” rather than “−1”, as is apparent from FIG. 4 . To the contrary, when the amplitude level of the reproduction signal at the data identification point is lower than the comparison level V th2 , there is a high probability that the level of the reproduction signal at the data identification point is “−1” rather than “0”. This difference also corresponds to determination in the state diagram of FIG. 3, i.e., whether the state before the state S 1 is the state So or the state S 2 . The comparator 15 compares the reproduction signal with the comparison level V th2 , detects the level of the reproduction signal at the data identification point, and outputs data representing the state before the state S 1 , i.e., the state S 0 or the state S 2 . This data is output from the output terminal and ground line of the comparator 15 to the maximum likelihood circuit 3 as an output 11 , i.e., 2-bit data “00” or “10”.
The comparator 16 compares the reproduction signal with the comparison level V th3 in FIG. 2 and outputs the comparison result to the maximum likelihood circuit 3 . In this case as well, when the amplitude level of the reproduction signal at the data identification point is higher than the comparison level V th3 , there is a high probability that the level of the reproduction signal at the data identification point is “1” rather than “0”, as is apparent from FIG. 4 . To the contrary, when the amplitude level of the reproduction signal at the data identification point is lower than the comparison level V th3 , there is a high probability that the level of the reproduction signal at the data identification point is “0” rather than “1”. This difference also corresponds to determination in the state diagram of FIG. 3, i.e., whether the state before the state S 2 is state S 1 or the state S 3 . The comparator 16 compares the reproduction signal with the comparison level V th3 , detects the level of the reproduction signal at the data identification point, and outputs data representing the state before the state S 2 , i.e., the state S 1 or the state S 3 . This data is output from the output terminal and power supply line of the comparator 16 to the maximum likelihood circuit 3 as an output 12 , i.e., 2-bit data “01” or “11”.
Finally, the comparator 17 compares the reproduction signal with the comparison level V th4 in FIG. 2 . In this case as well, when the amplitude level of the reproduction signal at the data identification point is higher than the comparison level V th4 , there is a high probability that the level of the reproduction signal at the data identification point is “2” rather than “1”, as is apparent from FIG. 4 . To the contrary, when the amplitude level of the reproduction signal at the data identification point is lower than the comparison level V th4 , there is a high probability that the level of the reproduction signal at the data identification point is “1” rather than “2”. This difference also corresponds to determination in the state diagram of FIG. 3, i.e., whether the state before the state S 3 is the state S 1 or the state S 3 . The comparator 17 compares the reproduction signal with the comparison level V th4 , detects the level of the reproduction signal at the data identification point, and outputs data representing the state before the state S 3 , i.e., the state S 1 or the state S 3 . This data is output from the output terminal and power supply line of the comparator 17 to the maximum likelihood circuit 3 as an output 13 , i.e., 2-bit data “01” or “11”. As described above, the binarizing circuit 2 detects the level of the reproduction signal at the data identification point by using the four comparators and outputs the detection result to the maximum likelihood circuit 3 as the state transition of the reproduction signal.
The above operation will be described in more detail. One of the states S 0 to S 3 , from which each of the four states S 0 to S 3 has changed at a time point T 1 , is detected in the following manner. First, the state S 0 changes from the state S 0 or the state S 2 , as can be seen from FIG. 3 . When the signal level at the time point T 1 is “−1”, the state S 0 has changed from the state S 2 , and when the signal level is “−2”, the state S 0 has changed from the state S 0 , as is apparent from FIG. 3 . When the output from the comparator 14 shown in FIG. 5 is “10”, there is a high probability that the signal level at the time point T 1 is “−1”, and it is therefore determined that the state S 0 has changed from the state S 2 at the time point T 1 , as shown in FIG. 6 . Similarly, it is determined that the state S 1 has changed from the state S 0 , the state S 2 has changed from the state S 3 , and the state S 3 has changed from the state S 1 . In this manner, state transition is periodically detected on the basis of the outputs from the binarizing circuit 2 .
The operation principle of the maximum likelihood circuit 3 will be described below with reference to FIGS. 6 and 7A to 7 E. In this embodiment, a maximum likelihood operation performed when the states have changed as shown in the trellis diagram of FIG. 6 will be described. FIG. 6 shows state transition detected by the binarizing circuit 2 , as described above. FIGS. 7A to 7 E are views showing the contents of data stored in the memory 5 in correspondence with the state transition. Time points T 1 to T 5 in FIGS. 7A to 7 E correspond to time points T 1 to T 5 in FIG. 6 . As described above in FIG. 1, the maximum likelihood circuit 3 is constituted by the memory 5 and the control circuit 6 for controlling data storage in the memory 5 . The memory 5 has four 2-bit memories in correspondence with the four states shown in FIG. 6 . The four 2-bit memories corresponding to 16 clocks are time-serially ensured. The path memory length of the memory 5 may be three or more times the number of states. In this case, a path memory length corresponding to 16 clocks is provided.
The operation principle will be described in detail. At the time point T 1 in FIG. 6, the state S 0 has changed from the state S 2 , as indicated by an arrow. In this case, as shown in FIG. 7A, data “2” representing that the state S 0 has changed from the state S 2 is stored in a memory corresponding to the state S 0 by the control circuit 6 . Similarly, at the time point T 1 , the state S 1 has changed from the state S 0 , the state S 2 has changed from the state S 3 , and the state S 3 has changed from the state S 1 . Therefore, data “0”, “3”, and “1” are stored in memories corresponding to the state S 1 , the state S 2 , and the state S 3 , respectively, by the control circuit 6 , as shown in FIG. 7 A.
At the time point T 2 , the state S 0 has changed from the state S 0 , as shown in FIG. 6 . Therefore, data “0” representing that the state S 0 has changed from the state S 0 is stored in the memory corresponding to the state S 0 , as shown in FIG. 7B (second column). Similarly, the state S 1 has changed from the state S 2 , the state S 2 has changed from the state S 3 , and the state S 3 has changed from the state S 1 . Therefore, data “2”, “3”, and “1” are stored in the memories corresponding to the states S 1 , S 2 , and S 3 , respectively, as shown in FIG. 7 B. Similarly, the control circuit 6 performs processing of shifting the data stored in the memory 5 at the time point T 1 in accordance with the data stored at the time point T 2 .
More specifically, since the state S 0 has changed from the state S 0 at the time point T 2 , the data for the state S 0 at the time point T 1 is transferred as data corresponding to the state S 0 . That is, since the data “2” is stored in correspondence with the state S 0 at the time point T 1 , the control circuit 6 stores the data “2” in the memory corresponding to the state S 0 , as shown in FIG. 7B (first column). At the time point T 2 , the state S 1 has changed from the state S 2 , the state S 2 has changed from the state S 3 , and the state S 3 has changed from the state S 1 . Therefore, the data “3” for the state S 2 at the time point T 1 is stored as data corresponding to the state S 1 , the data “1” for the state S 3 at the time point T 1 is stored as data corresponding to the state S 2 , and the data “0” for the state S 1 at the time point T 1 is stored as data corresponding to the state S 3 .
Similar processing is performed at the time point T 3 . The state S 0 has changed from the state S 2 , so that the data “2” is stored in the memory corresponding to the state S 0 , as shown in FIG. 7C (third column). Similarly, the state Si has changed from the state S 2 , the state S 2 has changed from the state S 3 and the state S 3 has changed from the state S 1 . Therefore, as shown in FIG. 7C (third column), the data “2”, “3”, and “1” are stored in the memories corresponding to the states S 1 , S 2 , and S 3 respectively. At the same time, the data stored at the time points T 1 and T 2 are shifted in accordance with the data at the time point T 3 .
More specifically, when the data at the time point T 2 are to be shifted in accordance with the data at the time point T 3 , the data “3” for the state S 2 at the time point T 2 is stored in the memory corresponding to the state S 0 , as shown in FIG. 7C (second column), because the state S 0 has changed from the state S 2 at the time point T 3 . Similarly, at the time point T 3 , the state S 1 has changed from the state S 2 , the state S 2 has changed from the state S 3 , and the state S 3 has changed from the state S 1 . Therefore, as shown in FIG. 7C (second column), the data “3” for the state S 2 at the time point T 2 is stored in the memory corresponding to the state S 1 , the data “1” for the state S 3 at the time point T 2 is stored in the memory corresponding to the state S 2 , and the data “2” for the state S 1 at the time point T 2 is stored in the memory corresponding to the state S 3 . The data are shifted in the memory 5 in the this manner. As a result, data of the second column in the memory is represented as “3”, “3”, “1”, and “2”, as shown in FIG. 7 C.
When the data at the time point T 1 are to be shifted in accordance with the data at the time point T 3 , the data “1” for the state S 2 at the time point T 1 is stored as data corresponding to the state S 0 , as shown in the first column of FIG. 7C, because the state S 0 has changed from the state S 2 at the time point T 3 . Similarly, at the time point T 3 , the state S 1 has changed from the state S 2 , the state S 2 has changed from the state S 3 , and the state S 3 has changed from the state S 1 . Therefore, as shown in the first column of FIG. 7C, the data “1” for the state S 2 at the time point T 1 is stored in the memory corresponding to the state S 1 , the data “0” for the state S 3 at the time point T 1 is stored in the memory corresponding to the state S 2 , and the data “3” for the state S 1 at the time point T 1 is stored in the memory corresponding to the state S 3 . As a result, data of the first column of the memory 5 is represented as “1”, “0”, and “3”, as shown in FIG. 7 C.
At the time point T 4 as well, the same processing as described above is performed. At the time point T 4 , the state S 0 has changed from the state S 2 , the state S 1 has changed from the state S 0 , the state S 2 has changed from the state S 1 , and the state S 3 has changed from the state S 1 . Therefore, as shown in FIG. 7D (fourth column), “2”, “0”, “1”, and “1” are stored in the memories corresponding to the states S 0 , the state S 1 , the state S 2 , and the state S 3 , respectively. In addition, the data stored at the time points T 1 , T 2 , and T 3 are shifted in accordance with the data stored in the time point T 4 . This processing is performed on the basis of the same principle as described above. When the data at the time point T 3 are shifted in accordance with the data at the time point T 4 , “3” is stored in the memory corresponding to the state S 0 , “2” is stored in the memory corresponding to the state S 1 , “2” is stored in the memory corresponding to the state S 2 , and “2” is stored in the memory corresponding to the state S 3 , as shown in FIG. 7D (third column).
The data stored at the time point T 2 are shifted in accordance with the data at the time point T 4 on the basis of the same principle as described above. As shown in FIG. 7D (second column), “1” is stored in the memory corresponding to the state S 0 , the “3” is stored in the memory corresponding to the state S 1 , “3” is stored in the memory corresponding to the state S 2 , and “3”is stored in the memory corresponding to the state S 3 . When the data at the time point T 1 are shifted in accordance with the data at the time point T 4 on the basis of the same principle, “0” is stored in the memory corresponding to the state S 0 , “1” is stored in the memory corresponding to the memory state S 1 , “1” is stored in the memory corresponding to the state S 2 , and “1”is stored in the memory corresponding to the state S 3 , as shown in FIG. 7D (first column).
The same processing is performed at the time point T 5 as well. At the time point T 5 , the state S 0 has changed from the state S 2 , the state S 1 has changed from the state S 2 , the state S 2 has changed from the state S 1 , and the state S 3 has changed from the state S 3 . Therefore, as shown in FIG. 7E (fifth column), “2” is stored in the memory corresponding to the state S 0 , “2” is stored in the memory corresponding to the state S 1 , “1”is stored in the memory corresponding to the state S 2 , and “3” is stored in the memory corresponding to the state S 3 . In addition, the data stored at the time point T 4 are shifted in accordance with the data at the time point T 5 on the basis of the same principle as described above. As a result, “1” is stored in the memory corresponding to the state S 0 , “1” is stored in the memory corresponding to the memory state S 1 , “0” is stored in the memory corresponding to the state S 2 , and “1”is stored in the memory corresponding to the state S 3 , as shown in FIG. 7E (fourth column).
The data at the time point T 3 are shifted in accordance with the data at the time point T 5 . As shown in the third column in FIG. 7E, “2” is stored in all the memories corresponding to the states S 0 to S 3 . When the data at the time point T 2 are shifted in accordance with the data at the time point T 5 , “3” is stored in all the memories corresponding to the states S 0 to S 3 , as shown in the second column in FIG. 7 E. When the data at the time point T 1 are shifted in accordance with the data at the time point T 5 , “1” is stored in all the memories corresponding to the states S 0 to S 3 , as shown in the first column in FIG. 7 E. In this manner, the control circuit 6 controls the data in the memory 5 in accordance with the state transition.
As is apparent from FIG. 7E, at the time point T 5 , the contents of data stored in the memory before the time point T 3 match in the memories corresponding to all the states. More specifically, at the time point T 2 , “2” is stored in all the memories corresponding to the states S 0 to S 3 . At the time point T 1 , “3” is stored in all the memories corresponding to the states S 0 to S 3 . At a time point T 0 , “1” is stored in all the memories corresponding to the state S 0 to S 3 . This means that the state has changed from the state S 2 at the time point T 2 , from the state S 3 at the time point T 1 , and from the state S 1 at the time point T 0 . Consequently, as is apparent from the state diagram shown in FIG. 3, since the data for the state S 2 is “10”, the data for the state S 3 is “11”, and the data for the state S 1 is “01”, the reproduction data can be determined as “0110”.
A detailed arrangement of the maximum likelihood circuit 3 will be described below. FIG. 8 is a circuit diagram showing an example of the maximum likelihood circuit 3 . Referring to FIG. 8, the inputs 10 to 13 correspond to the outputs from the binarizing circuit 2 shown in FIG. 5 . These outputs are input to the corresponding memory arrays of the memory 5 in the maximum likelihood circuit 3 , respectively. More specifically, the output 10 is input to a memory array consisting of 2-bit memories 20 to 24 p corresponding to the state S 0 , the output 11 is input to a memory array consisting of 2-bit memories 21 to 25 p corresponding to the state S 1 , the output 12 is input to a memory array consisting of 2-bit memories 22 to 26 p corresponding to the state S 2 , and the output 13 is input to a memory array consisting of 2-bit memories 23 to 27 p corresponding to the state S 3 . As the path memory length of each memory array, a length corresponding to 16 clocks is ensured, as described above. In addition, select circuits 28 a to 28 o for shifting data are arranged between the memories of each memory array (to be described later in detail).
As the 2-bit memory, two DFFs (data flip-flops) 31 and 32 are used, as shown in FIG. 9. A reproduction clock 33 is input from a PLL circuit (not shown) to the two DFFs 31 and 32 , so that data is shifted by this reproduction clock. The data input to the 2-bit memories 20 to 23 are output as outputs 10 a , 11 a , 12 a , and 13 a in synchronism with the reproduction clock. These outputs are input to the next 2-bit memories 24 a , 25 a , 26 a , and 27 a. These 2-bit memories have the same arrangement as shown in FIG. 9 . The 2-bit memories 24 a , 25 a , 26 a , and 27 a are respectively connected to 2-bit memories 24 b , 25 b , 26 b , and 27 b through the select circuit 28 a. When data are to be shifted, as described above, the select circuit 28 a shifts the data by switching connection of the memories.
FIG. 10 is a circuit diagram showing an arrangement of the select circuit 28 a. The select circuit 28 a is constituted by four multiplexers 40 to 43 corresponding to the states S 0 to S 3 . The multiplexers 40 to 43 are connected to the input-side memories 24 a , 25 a , 26 a , and 27 a , respectively, so that the data in the memories are shifted in accordance with the switching operation of the multiplexers 40 to 43 .
In this case, the switching operation of the multiplexers 40 to 43 is controlled such that the data stored in the memories 24 a , 25 a , 26 a , and 27 a are shifted in accordance with the corresponding outputs 10 a , 11 a , 12 a , and 13 a , i.e., currently input data. Though not illustrated in FIG. 8, the control circuit 6 controls the switching operation of the multiplexers.
At the time point T 1 in FIG. 6, the memory 5 stores data contents as shown in FIG. 7 A. In fact, these data are positioned at the second memory of each memory array shown in FIG. 8 . More specifically, at the time point T 1 , “2” is stored in the memory 24 a, “0” is stored in the memory 25 a, “3” is stored in the memory 26 a , and “1” is stored in the memory 27 a. In this state, the next data shown in the second column of FIG. 7B are input to the memory array, so that “0” is stored in the memory 20 , “2” is stored in the memory 21 , “3” is stored in the memory 22 , and “1” is stored in the memory 23 . At this time, the select circuit 28 a shifts the data at the time point T 1 in accordance with the data input at that time under the control of the control circuit 6 , as in the above description of the operation principle. More specifically, since the data input to the memory array corresponding to the state S 0 is “0”, data corresponding to the state S 0 at the time point T 1 , i.e., “2” stored in the memory 24 a is shifted to the next memory 24 b corresponding to the state S 0 . The data is shifted by connecting the memories 24 a and 24 b through the multiplexer 40 in the select circuit 28 a.
The data input to the memory array corresponding to the state S 1 is “2”. Similarly, data corresponding to the state S 2 , i.e., “3” stored in the memory 26 a is shifted to the next memory 25 b corresponding to the state S 1 . In this case, the memories 26 a and 25 b are connected through the multiplexer 41 . The data input to the memory array corresponding to the state S 2 is “3”, and the data corresponding to the state S 3 i.e., “1” as the data stored in the memory 27 a is shifted to the next memory 26 b. At this time, the memories 27 a and 26 b are connected through the multiplexer 42 . Finally, the data “1” is input to the memory array corresponding to the state S 3 . The data corresponding to the state S 1 , i.e., “0” stored in the memory 25 a is shifted to the next memory 27 b. At this time, the memories 25 a and 27 b are connected through the multiplexer 43 . The select circuit 28 a shifts the data in this manner.
In the respective memory arrays, a select circuit is connected to the memories 24 b , 25 b , 26 b , and 27 b , 2-bit memories are connected to the select circuit, and another select circuit is connected the 2-bit memories. In this manner, memories and select circuits are alternately arranged, and 2-bit memories 24 p , 25 p , 26 p , and 27 p are arranged at the end of the memory arrays. The data shift operation in the memories by the select circuit 28 a has been described above. At the subsequent memories of the memory arrays, the control circuit 6 controls each select circuit to shift the data in accordance with the corresponding data inputs, as in the description of the operation principle with reference to FIGS. 6 and 7. In each memory array, data is sequentially shifted in synchronism with the reproduction clock. As in the above description of the operation principle, when data are output to the memory 24 p , 25 p , 26 p , and 27 p at the output stage, the data contents match for all the states. Therefore, when upper or lower bits are extracted from the 2-bit memories 24 p , 25 p , 26 p , and 27 p at the output stage, reproduction data can be obtained.
As described above, in this embodiment, information can be reproduced using the memory arrays corresponding to the number of the states of the reproduction signal and the memory 5 having a predetermined path memory length. Maximum likelihood can be performed with a smaller memory capacity than that of the prior art. When the number of states is large, the number of memory arrays of the memory 5 is increased accordingly. With this arrangement, maximum likelihood can be similarly performed, so this arrangement can cope with a large number of states.
Another embodiment of the present invention will be described below. As shown in the state diagram of FIG. 3, the number of state transitions is two. Therefore, the number of bits necessary to transfer state transition can be one instead of two. In this embodiment, data corresponding to each state is represented by one bit. FIG. 11 is a circuit diagram showing a binarizing circuit 2 used in this embodiment. In this binarizing circuit, each of comparators 14 to 17 outputs one signal, i.e., 1-bit data representing state transition to a maximum likelihood circuit 3 . The operation of the binarizing circuit 2 is the same as in the first embodiment shown in FIG. 5 .
FIG. 12 is a circuit diagram showing the maximum likelihood circuit 3 used in this embodiment. In this case as well, 1-bit memories 50 to 52 are arranged in place of the 2-bit memories 20 to 23 of the first embodiment. Select circuits 68 a to 68 o are also different from those of the first embodiment. FIG. 13 shows the select circuit of this embodiment. In FIG. 13, since the number of state transitions is two, each of multiplexers 60 to 63 has two input terminals. The operation of the maximum likelihood circuit shown in FIG. 12 is the same as in the first embodiment. In this embodiment, 1-bit data is processed. Therefore, the memory capacity can be further decreased as compared to the first embodiment, and the circuit arrangement can be simplified.
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A data reproducing apparatus for reproducing data subjected to convolution by partial response, by using maximum likelihood, includes a memory including a plurality of memory arrays which respectively correspond to plural states that the data can take and each of which has a predetermined number of regions each corresponding to a time point. A detecting device periodically detects, from the data, states before the plural states have been shifted, and a control device causes values respectively representing the detected states before shifting to be sequentially stored in the regions of the memory arrays every time detection is performed by the detection device, causing the values previously stored in the memory arrays to be replaced in accordance with the detected states before shifting, and when all values stored in the regions of the memory arrays corresponding to the same time point match, reproducing the data on the basis of the matching value.
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This application claims benefit of provisional application Ser. No. 60/026,313, filed Sep. 18, 1996
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the fields of molecular virology and immunology. More specifically, the present invention relates to viral defective interfering particles and uses thereof.
2. Description of the Related Art
"Incomplete particles" were discovered by von Magnus in 1947 during successive undiluted passages of influenza viruses (von Magnus '47). In general, these incomplete particles contain less than a full-length genome and are replication-defective. They can be rescued by and interfere with the replication of homologous helper viruses.
To date, most defective interfering particles are discovered in laboratory settings (Holland et al., '87 & '91; Dimmock '96). It is not known if defective interfering particles could also exist in natural infection in humans. Furthermore, most defective interfering studies have demonstrated a correlation between genomic deletion and the defective interfering phenotype. Whether deletion is indeed the cause to the defective interfering phenomenon and whether the identified deletion alone is necessary and sufficient for the defective interfering behavior, have never been proven experimentally.
Another important characteristic of these incomplete particles is their ability to enrich their proportion of the total viral yield in mixed infection with wild type and incomplete viruses (Holland '87). Based on these properties, Huang and Baltimore defined these biologically active defective particles as defective interfering (DI) particles and the replication competent homologous virions as standard virus (Huang & Baltimore, '70). Defective interfering particles are wide-spread in many DNA and RNA viruses in bacteria, plants and animals (Holland, '87; Huang & Baltimore, '77). The biological significance of these defective interfering particles remains an important and intriguing issue in virology and evolutionary biology. Defective interfering particles may play a key role in disease progression of chronic infection.
Hepatitis B virus (HBV) is one of the most common infectious agents in humans (approximately 200 million chronic carriers of HBV worldwide) and chronic active hepatitis B infection leads to the development of cirrhosis and liver cancer (Shih et al, '96). HBV infection is the most common cause of death due to viral infections in humans and is behind only malaria as a cause of death from an infectious agent. Every newborn should be vaccinated against HBV. To date, there is no simple, specific and effective therapy for a deadly fulminant hepatitis B infection.
The molecular and cellular mechanism of chronicity and pathogenesis of HBV infection remains to be elucidated. HBV replication in various hepatoma cell lines in tissue culture does not exhibit any apparent cytopathic effect (Sureau et al., '87; Shih et al., '89). It is generally believed that hepatitis and liver damage are due to immune-mediated cytotoxicity (Milich '91; Chisari & Ferrari, '95). HBV core antigen (HBcAg or nucleocapsid protein) has been shown to be a major target of T cell immunity (Mondelli et al., '82, Vento et al., '85; Ferrari et al., '90; Tsai etal., '92).
Immune escape mutations are known to occur within the major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocyte (CTL) epitopes (Pircher et al., '90; Phillips et al., '91). Surprisingly, frequent missense mutations of HBcAg were found to coincide with mapped MHC class II-restricted T cell epitopes (Hosono et al., '95; Lee et al., '96; Bozkaya et al., '96). In addition to these missense mutations, a naturally occurring core antigen internal deletion (CID) was found to be geographically ubiquitous in 4 out of 4 asymptomatic HBV carriers (Okamoto et al., '87), 7 out of 11 chronic active hepatitis (Wakita et al., '91), 2 out of 10 hepatocellular carcinoma tissues (HCC) (Hosono et al, '95) and 6 out of 6 HBV-infected immunosuppressed transplantation patients (Gunther et al., '95). More often, these deletions were in-frame, occurring around HBcAg codon 80-130, and varying in size from 18 to 61 amino acids (approximately 10-33% of wild type HBcAg). The amino terminal moiety of HBcAg is responsible for the polymerization of nucleocapsid particles, while the arginine-rich carboxyl terminus of HBcAg is known to be involved in binding of HBV pregenomic RNA and the reverse-transcribed cDNA (Gallina et al., '89; Hatton et al., '92). The internal deletion of HBcAg is located outside the nucleic acid binding domain and its biological functions have been unclear.
Hepatitis B virus was discovered by Blumberg in 1964 and the initial reports of core internal deletion (CID) mutants of HBV was by Okamoto et al. in 1987 and Wakita et al. in 1991. However, there has been no report of HBV defective interfering particles. Previously, Gerin et al. reported the identification of HBV defective interfering particles based on the morphology of "empty" particles under electron microscope. (American J. of Path., 81:651-668, 1975). As mentioned earlier, the definition of defective interfering is a functional one, not strutural. Morphological features are neither a necessary nor a sufficient criterion for the definition of defective interfering particles. To the contrary, defective interfering particles are not "empty" or without viral genome. Defective interfering particles do have a functionally defective genome. Therefore, defective interfering particles are a life form which can perpetuate itself, while "empty" particles are not life form, since they are simply protein aggregates and do not have a genome to duplicate themselves. Although there has been speculation that CID mutants of HBV could be defective interfering particles (Akarca & Lok, '95), no experimental data, evidence and proof of the four major characteristic features of defective interfering particles, i.e., replication defective, rescuability by helper viruses, interference of helper virus, and enrichment of defective interfering particles, has been reported. As admitted by the authors, "We acknowledge that we do not have direct proof that the deletions result in defective genomes" (p. 1825 near the end, Akarca & Lok, '95). This deficiency in the prior art's ability to determine defective interfering particles is in part due to both technical and conceptual difficulties.
The conventional approach of identifying defective interfering particles relies on plaque assay and infection assay. Since HBV infection in tissue culture is not a well established procedure, and HBV replication in tissue culture does not produce plaques, there is no prior art as to how to determine the presence of defective interfering particles without infection and plaque assay. The CID mutants also contain a number of mutations elsewhere in the HBV genome. It is not obvious how one could circumvent these complications to study the native naturally occurring CID mutation without the enormous complication from other coexisting mutations in the CID variants.
A misconceptual difficulty in the prior art involves the nomenclature of defective interfering particles. In fact, "enrichment" is another equally important feature of defective interfering viruses. The prior art nomenclature often leads to the misconception that the overall viral titer will be dramatically decreased due to a dominant negative effect of defective interfering particles.
Laboratory-derived defective interfering particles of human hepatitis A virus (HAV) have been reported (Siegl et al., '90 and '93). However, these HAV-defective interfering viruses were originated from tissue culture in the laboratory setting. As admitted by the authors (Siegl et al., '90, page 106): " . . . Under conditions of natural infection, however, defective interfering particles of the very same viruses have not yet been observed. Hence, it is not known whether the predicted positive and/or negative effects of this specific class of particles play the expected role during natural infection . . . ". Second, HAV and HBV are different viruses. HAV is an RNA virus transmitted via the oral-fecal route while HBV is a DNA virus transmitted through blood and intimate contact.
The prior art is deficient in the lack of the understanding, experimental support, evidence and proof of the functional behaviors of defective interfering particles in human viruses in natural infections. The present invention fulfills this longstanding need and desire in the art by providing experimental data, evidence and proof of the functional features of human defective interfering viruses.
SUMMARY OF THE INVENTION
Internal deletion of human hepatitis B virus (HBV) core antigen is frequently found in HBV infections worldwide. Functional characterization of these mutants revealed features reminiscent of defective interfering particles (DI) originally discovered in influenza virus half a century ago. Internal deletion of HBV core antigen is necessary and sufficient for the defective interfering phenotype. The virus-virus interactions between the populations of wild type and defective interfering particles could provide a way of quantitative modulation of immune targets in virus-host interactions in pathogenesis and persistence of HBV infection. The present invention demonstrates the first experimental evidence that defective interfering variants exist in natural infection in humans. The present invention also determined whether the naturally occurring CID mutation, identified from HBV-infected human patients, can confer any defective interfering phenotype when this mutation is introduced into a wild type HBV background.
In one embodiment of the present invention, there is provided a composition of matter comprising a defective interfering virus particle, wherein said particle naturally occurs in a human infection and wherein said particles has a naturally occurring core antigen internal deletion.
In another embodiment of the present invention, there is provided a pharmaceutical composition, comprising defective interfering virus particle and a pharmaceutically acceptable carrier.
In yet another embodiment of the present invention, there is provided a method for preparing defective interfering virus, comprising the steps of: (1) introducing a defective interfering virus and a complementing plasmid expressing a wild type virus core antigen and optionally containing a drug resistance gene, into a recipient cell; (2) selecting for stably transfected colonies; (3) growing the drug resistant cells and screening for the production of virus DNA replication; and (4) collecting defective interfering virus particles from the medium.
In still yet another embodiment of the present invention, there is provided a vaccine, comprising a defective interfering virus particle of the present invention.
In yet another embodiment of the present invention, there is provided a vector comprising a DNA sequence coding for a defective interfering virus particle of the present invention, wherein the vector is capable of replication in a host and said vector comprises, in operable linkage: a) an origin of replication; b) a promoter; and c) a DNA sequence coding for a defective interfering virus particle.
In yet another embodiment of the present invention, there is provided a host cell transfected with a vector of the present invention, said vector expressing a defective interfering virus particle of the present invention.
In yet another embodiment of the present invention, there is provided a novel cell line producing the defective interfering virus particle of the present invention.
Other and further aspects, features, and advantages of the present invention will be apparent from the following description of the presently preferred embodiments of the invention given for the purpose of disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
So that the matter in which the above-recited features, advantages and objects of the invention, as well as others which will become clear, are attained and can be understood in detail, more particular descriptions of the invention briefly summarized above may be had by reference to certain embodiments thereof which are illustrated in the appended drawings. These drawings form a part of the specification. It is to be noted, however, that the appended drawings illustrate preferred embodiments of the invention and therefore are not to be considered limiting in their scope.
FIG. 1 shows that the HBV-CID variants are replication defective upon transfection into human hepatoma cell line Huh7. FIG. 1A illustrates the deletion regions of HBV core antigen of two different CID variants identified from two different hepatoma patients T85 and T109. This deletion region does not overlap with any other HBV genes, including X, P (polymerase) and pre-S/S (envelope). DEL85 deleted amino acids 88-135 while DEL109 deleted amino acids 82-122. To construct plasmids pDEL85 and pDEL109, the DNA fragments of nucleotide 1636 to 2688 containing the mutant HBV core gene were PCR amplified from total DNA samples of hepatomas T85 and T109 (Hosono et al., '95), and were used to replace both copies of the wild-type counterparts of an HBV tandem dimer plasmid (Roychoudhury & Shih, '91). FIG. 1B shows that five days after transfection with wild type or mutant HBV, viral DNAs of intracellular core particles were harvested and subjected to Southern blot analysis using the 3.1 kb full-length vector-free HBV DNA probe (Yuan et al, '95). No detectable replication of mutants pDEL85 and pDEL109 were observed. FIG. 1C shows that encapsidation activity was assayed by primer extension using core particle-associated viral RNA from transfected culture and a 5'-end-labeled oligonucleotide primer (nucleotides 1980 to 2001) (Roychoudhury et al., '91). FIG. 1D shows that similar levels of the pregenomic RNA were produced from wild type and CID mutants. Twenty five micrograms of cellular RNA from transfected cells were subjected to Northern blot analysis and probed with a 3.1 kb full-length HBV probe (top). Similar amounts of cellular RNA were used in each lane as indicated by similar intensity of ethidium bromide staining (bottom). FIG. 1E shows that the reporter gene of chloramphenicol acetyl transferase (CAT) gene was fused in-frame with the carboxyl termini of the pol genes originated from pWT, pDEL85, and pDEL109. CAT activities of the pol-CAT fusion proteins were measured two days after transfection (Pei & Shih, '91). FIG. 1F shows that the core proteins produced from pWT, pDEL85, and pDEL109 were analyzed by immunoblot assay using a rabbit polyclonal anti-core antibody (Lanford).
FIG. 2 shows that the replication defective CID mutants can be rescued by trans-complementation with wild-type HBV core antigen and secreted into media with a similar buoyant density to wild-type HBV. FIG. 2A shows that various doses of a wild-type HBcAg expression vector, pSVC, was co-transfected with constant amount of pWT, pDEL85 and pDEL109, respectively. Viral DNAs of intracellular core particles were analyzed by Southern blot using the 3.1 kb full-length HBV probe. FIG. 2B shows that ten micrograms of pDEL85 or pDEL109 was either transfected alone or with 10 μg of pSVC. Extracellular HBV particles from 20 ml conditioned media were collected 5 days after transfection via centrifugation through a 20% sucrose cushion. FIG. 2C: medium collected from cells transfected with 10 μg of pWT. Viral particles in the media were purified and subjected to isopycnic centrifugation. Fractions were assayed for HBsAg using Abbott Auszyme EIA kit (top). Southern analysis located the fractions containing HBV genomes(bottom). FIG. 2D shows the medium from cells transfected with 10 μg of DEL85 and pSVC was assayed.
FIG. 3 shows the defective interfering phenomenon of HBV-CID variants were observed in human hepatoma Huh7 and HepG2 (FIG. 3D) cells. FIG. 3A shows that seven μg of pWT was co-transfected with increasing amounts of pDEL85, pDEL109, or pTGAGC, respectively. HBV core particle associated DNA was analyzed by Southern blot using 3.1 kb full-length HBV fragment. Replicative intermediates of relaxed-circular (RC) and single-stranded (SS) DNAs are indicated by arrows. FIG. 3B shows that after the 3.1 kb full-length HBV probe was removed from the nitrocellulose filter, the same filter was reprobed with a radio-labelled wild-type specific DNA fragment. The wild-type specific DNA fragment is 135 nucleotides in length (from nucleotide 2141 to 2275) and was amplified by PCR using pWT as a DNA template. The relative intensity of replicative intermediates was measured by densitometer image analysis. FIG. 3C: after the wild-type specific probe was removed, the nitrocellulose filter of FIG. 3B was reprobed with DEL85-specific and DEL109-specific fragments. The DEL85 specific DNA probe is 181 nucleotides (from nucleotide 2041 to nucleotide 2365 with a deletion of 144 nucleotides) and synthesized by PCR using pDEL85 as a DNA template. The DEL109 specific probe is 208 nucleotides (from nucleotide 2041 to 2365 with a deletion of 123 nucleotides) and synthesized by PCR using pDEL109 as a DNA template. The non-specific hybridization of background noise around SS DNA region was observed in lanes transfected with pWT alone or cotransfected with pTGAGC. FIG. 3D shows that the HepG2 human hepatoblastoma cell. line was used in the same assay with a wild type-specific probe. FIGS. 3E and 3F shows that the defective interfering phenomenon was also observed when the secreted extracellular HBV particles were analyzed in the replication assay using a full-length 3.1 kb HBV probe (FIG. 3E) and the wild type-specific probe (FIG. 3F). FIG. 3G shows a cartoon illustration of the wild type-specific and DEL- specific probes used above.
FIG. 4 shows the comparison of the relative abundance of wild type and CID mutants via PCR analysis using HBV core gene-specific primers (16). Top, An aliquot of the premixed donor plasmid DNAs (pWT and pDEL85) was amplified by PCR before transfection. The results for pWT and pDEL109 (data not shown) are very similar to that of pWT and pDEL85. Bottom, seven μg of pWT were cotransfected with increasing amounts of pDEL85 (right) or pDEL109 (left) into Huh7 cells, and core particle-associated DNAs were harvested 5 days after transfection. Identical PCR conditions were used for both amplifications of the plasmid and core particle-associated DNAs. The relative intensities of full-length and deleted core gene fragments were measured by densitometric scanning.
FIG. 5 shows that the defective interfering phenomenon conferred by CID variants is species specific and not mediated through soluble factors. FIG. 5A shows the conditioned media of Huh7 cells were collected 2 days after transfection with various combinations of plasmids pWT, PSVC, and pDEL85. Huh7 cells transfected with 7 μg of pWT were then incubated with 5 ml of each respective conditioned media and 5 ml of fresh media. As a control, transfected culture incubated with 10 ml of fresh media were included in the last lane. Full-length 3.1 kb HBV DNA was used as a probe in replication assay. FIG. 5B shows that seven micrograms of duck hepatitis B virus plasmid (pSP65DHBV5.1) was co-otransfected with increasing amount of pDEL85, pDEL109, or pTGAGC into Huh7 cells. Replication assay was performed as described in FIG. 1 above and probed with 3.1 kb full-length DHBV fragment.
FIG. 6 shows that the internally deleted core proteins can be detected in vitro but not in vivo. The flu-epitope peptide sequence (YPYDVPDYA) from the influenza hemagglutinin (Field et al., '88) was introduced into the carboxyl termini of the core proteins using an SV40 expression vector. The wild-type core protein from pWT, and the wild-type and deleted core-flu fusion proteins from pSVCflu, pSV85flu, and pSV109flu were measured by immunoblot assay using anti-core (FIG. 6A) or anti-hemagglutinin (FIG. 6B) antibody. FIG. 6C shows that the absence of the deleted core-flu fusion protein is not due to the instability of its mRNA. Twenty-five micrograms of cellular RNAs from cells transfected with either pSVCflu, pSV85flu, or pSV109flu were hybridized with wild-type-, DEL85-, and DEL109-specific RNA fragments respectively in the RNase protection assay. FIGS. 6D and 6E show that if the deleted core gene is indeed translatable, the wild-type and deleted core proteins were expressed in vitro from pSPC, pSP85, and pSP109 using rabbit reticulocyte lysate (Promega Co., Wis.). The in vitro synthesized proteins were analyzed on a 12% acrylamide gel either in the presense (FIG. 6D, top) or absence (FIG. 6E) of 2-mercaptoethanol. pSP109ATA is a similar plasmid to pSP109, except that the initiation codon ATG of the core gene has been changed to ATA. To control for the equal amount of RNAs used in the in vitro translation experiment described in FIG. 3D, the in vitro synthesized RNA transcripts from these plasmids were quantitated by electrophoresis (FIG. 6D, bottom). The β-actin transcript with a size of 360 nucleotide from pRT1 was used as positive control and size marker. FIG. 6F shows that no apparent interference effect on wild type HBV replication was observed by the deleted core protein from cotransfected pSV109 or pSV109ATA. The replication assay was performed as described using the 3.1 kb full-length HBV probe.
FIG. 7 shows the cycling-like phenomenon of HBV defective interfering mutants in the serially collected serum samples (1989-1993) from an HBV-infected patient with hepatocellular carcinoma. FIG. 7A shows that HBV DNA in the sera were prepared (Wakita et al., '91) and PCR amplified as detailed (Hosono et al., '95). Amplified DNA fragments were separated by agarose gel electrophoresis and stained with ethidium bromide. ALT (alanine amino transferase) has been used as a clinical indicator of liver damage. The normal upper limit of ALT activity is approximately 40 IU/liter. Acute hepatitis patients often have several hundred IU per liter. FIG. 7B shows the comparison of HBV core amino acid sequences among DEL85, wild type (consensus), and viruses serially collected from a chronic active hepatitis B patient (December 1989-December 1993). The consensus sequences used here are the most prevalent HBcAg sequences in Asia (Ono et al., '83; Kobayashi & Koike, '84). PCR amplified DNA fragments were gel-purified, subeloned and sequenced as described (Hosono et al., '95). The letter "Z" represents a translational stop codon and the letter "X" represents deletion. The symbol "/" represents frame shift mutation. Subtype specific sequence heterogeneity was indicated by *. Hotspot mutational domains I and V coincides with MHC class II-restricted T cell epitopes (Hosono et al., '95). Recent studies also indicated that domain IV contains an MHC class II- restricted T cell epitope (Jung et al., '95; Tsai et al., '96). The sequences of CID mutants are highlighted with yellow color. Frequent missense mutations at codons 13, 151, and 182 are present in helper virus and absent in defective interfering virus, and are highlighted with pink color. pol represents the overlapping polymerase gene. FIG. 7C shows the case F090245 from 1986 to 1991. Serum samples from 1987 and 1988 were not available. FIG. 7D shows the case F090063 from 1986 to 1991. Each sample was PCR-amplified, then gel analyzed in duplicate.
FIG. 8 shows that the same CID deletion as DEL85 was also observed in a British patient and a patient from Hongkong.
FIG. 9 shows that stable Q7 rat hepatoma cell lines were transfected with plasmids pSVC and pSV2NeoDEL85 and were selected with G418 as described previously. HBV core particle-associated DNA was purified from 6 independent clones and characterized by gel electrophoresis and Southern blot analysis. Two neomycin-resistant clones, 1-12-2 and 1-15-1, exhibited the pattern characteristic of HBV replication intermediates such as relaxed circular (RC) and single stranded forms of DNA.
DETAILED DESCRIPTION OF THE INVENTION
Definitions
The following terms are defined as used herein. Terms not defined should be interpreted as is usual and customary in the fields of molecular biology and virology.
As used herein, the term "replicative defective" shall mean that a virus is unable to duplicate or multiply by itself.
As used herein, the term "interfere" shall mean a decrease in the number of helper viruses.
As used herein, the term "incomplete particle" shall refer to the virus variants that can interfere with the replication of other viruses.
As used herein, the term "defective interfering" shall refer to the fact that viral particles are replication defective, rescuable by helper viruses, have an interference effect on wild type virus, and enrich the replication defective virus.
As used herein, the term "immune escape mutation" shall mean a mutation which allows immune evasion from a host's immune surveilance.
As used herein, the term "trans complementation" shall mean a genetic experiment designed to determine if two different genetic entities, e.g., two different viruses or plasmids, could cross support each other.
As used herein, the term "cycling-like phenomenom" shall mean a dynamic equilibrium between the defective interfering particle and the helper viruses and describes the reciprocal relationship between the defective interfering and the helper viruses.
As used herein, the term "core antigen internal deletion" or "CID" shall mean a deletional mutation within the central portion of the HBV core antigen, e.g., around amino acids 80 to 130.
As used herein, the term "rescuability" shall mean the ability to survive when supplied with the normal functional core proteins.
As used herein, the term "enrichment" shall mean to increase in proportion in a mixture of different viruses.
As used herein, the term "hotspot" or a "hotspot mutation" shall mean a highly frequent mutation.
As used herein, the term "immunologically anergic" shall mean unable to induce an immune response.
As used herein, the term "immunogenic agent" refers to an agent used to stimulate the immune system of a living organism, so that one or more functions of the immune system increased and is directed towards the immunogenic agent. Immunogenic agents include vaccines. Immunogenic agents can be used in the production of antibodies, both isolated polyclonal and monoclonal antibodies using techniques well known to those of ordinary skill in this art.
As used herein, the term "vaccine" is meant an agent Aused to stimulate the immune system of a living organism so that protection against future harm is provided. Immunization refers to the process of inducing a continuing high level of antibody against cellular immune response in which T-lymphocytes can either kill the pathogen and/or activate other cells, e.g., phagocytes to do so in an organism, which is directed against a pathogen or antigen to which the antigen has been previously exposed.
As used herein, the term "individual" is meant any member of the subphylum Vertebrata. All vertebrates are basically capable of responding to vaccines and producing antibodies.
Although vaccines are commonly given to mammals, e.g., humans and dogs, vaccines for commercially raised vertebrates of other classes may be within the scope of the present invention.
Vaccination
An "effective amount" of live-virus or subunit vaccine prepared as disclosed herein can be administered to a subject (human or animal) alone or in conjunction with an adjuvant (e.g. as described in U.S. Pat. No. 5,223,254 or Stott et al., (1984) J. Hyg. Camb. 251-261) to induce an active immunization against a pathogenic infection. An effective amount is an amount sufficient to confer immunity against the pathogen and can be determined by one of skill in the art using no more than routine experimentation.
Determination of an effective amount may take into account such factors as the weight and/or age of the subject and the selected route for administration. Vaccines can be administered by a variety of methods known in the art. Exemplary modes include oral (e.g. via aerosol), intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, parental, transdermal and intranasal routes. If necessitated by a particular mode, the vaccine may be encapsulated.
Current commercial HBV vaccine consists of HBV-encoded envelope protein alone. It does not have other HBV-encoded protein antigens, such as polymerase, preS1, preS2 or core antigen (also known as nucleocapsid antigen). Pre-S1 antigen is present in HBV virion and effective in protection (Milich et al., '85; Neurath et al., '85 & '88). In addition, the HBV-defective interfering vaccine should be virtually identical in every aspect to the fully infectious HBV in nature, except that HBV-defective interfering mutant is not viable and not infectious. Thus, the HBV-defective interfering vaccine of the present invention will produce a much stronger, more effective, and long-lasting protection against HBV infection than the current surface antigen subunit vaccine. The HBV-defective interfering vaccine failure rate would also be much lower.
The HBV-defective interfering vaccine of the present invention may not be suitable for a small fraction of babies born to HBV carrier mothers, i.e., babies preinfected with HBV in utero or perinatally infected with HBV during delivery before vaccination. In both cases, the conventional subunit vaccine could not be effective either. The HBV-defective interfering vaccine of the present invention is most safe for babies born to healthy noncarrier mothers, who are the majority (>80 or 90%) of the pregnant population. One specific application of the HBV-defective interfering vaccine of the present invention is to use an active-passive immunization protocol (Beasley et al., '83). That is, one would administer to the newborns both HBIG (hepatitis B immunoglobulin) and the HBV-defective interfering vaccine of the present invention, instead of conventional subunit vaccine, within the first two hours after delivery.
The art of vaccine production and delivery is well established. A person having ordinary skill in this art would be able to use the defective interfering particles of the present invention in a vaccine and determine the appropriate dosages without undue experimentation. One possible regimen for vaccination would be: 2-3 doses of alum-absorbed defective interfering particles 5 μg/ml are injected intramuscularly. The defective interfering virus can be prepared from a tissue culture medium of a stable hepatoma cell line producing and secreting defective interfering, e.g., HBV defective interfering particles.
The procedure for preparing defective interfering viruses are detailed below as an example and the methodology is further described in Shih et al., '89; U.S. Pat. No. 5,156,970. These steps include (1) Introduce both defective interfering viruses, e.g., HBV-DEL85 and the complementing plasmid, e.g., pSVC which expresses the wild type HBV core antigen, into the same recipient cell (e.g., HepG2, Huh7 or Morris hepatoma 7777 cell lines) via a gene transfer techniques, e.g., calcium phosphate transfection technique, lipofectin technique. Ideally, but not necessarily, one of these plasmids contains a drug resistance gene, e.g., neomycin resistance. (2) Select for the stably transfected colonies using a medium containing selective drugs, e.g., neomycin resistance. (3) Grow up these drug resistant cells and screen for the production of HBV surface antigen and core/e antigen in the medium via enzyme immunoassay, e.g., Abbott EIA kit. (4) Cell lines which can produce both surface and core/e antigen are screened for HBV DNA replication using Southern blot analysis and the full length HBV DNA probe. HBV DNA is isolated from the intracellular core particles (for further details, see Examples 3 and 5 below). (5) Confirm the above Southern results using a defective interfering virus-specific probe, e.g., DEL85 mutant specific probe described in Example 14 and FIG. 3C. (6) Screen for the cell lines that produce the most abundant quantity of defective interfering viruses as in steps 4 and 5 described above. Test the genetic stability of the chosen cell lines by comparing the replication activities of cells in the presence or absence of the selective drug in the medium for a certain period (e.g., one month). Alternatively, genetically stable DI virus-producer cell lines can be further adapted or selected for growth in medilim of lower cost, such as lower concentration of fetal bovine serum, or calf serum instead of fetal calf serum. Selected clones can also be adapted to grow in suspension, instead of adhering to the surface of the culture container. Store such high-producer cell lines in Dulbecco Modified Eagle's Medium (DMEM) containing 10% fetal bovine serum (FBS). Long term storage of these cell lines can be made using DMEM containing 10% fetal bovine serum and cryopreseravatives, e.g., 10% glycerol or 10% DMSO, in liquid nitrogen. Reactivation of these cell lines can be done quickly by thawing the frozen vials at 37° C. in a water bath and gradually diluting the cell culture to a 10 fold final volume using DMEM with 10% FBS. Once the most ideal cell clones have been selected (i.e., highest yield of DI virus production, genetically stable, grow well in inexpensive medium, adapted for scale-up production, and other desirable features), they can be expanded in cell number and aliquoted to a number of frozen vials (e.g., 100 vials). These are referred to as cells of early passages. Cells from the early passages can be again expanded and aliquoted into a large number of vials, referred to as cells of late passages. When cells of late passages are no longer available (e.g., due to the loss of rulture by microbial contamination or inadequate culture condition), cells from early passage will be used to create more frozen cells of late passage. This is the so-called seed-lot system commonly used for manufacturing biological products. The method for the scale up production of DI virus will be the same as the routine scale up production of mammalian cells. (7) Defective interfering virus particles are collected from the medium (See Example 4). (8) The defective interfering virus pellets are resuspended in phosphate buffered saline (PBS). To clean up the virus preparation further, one can dialyze against PBS at 4° C. overnight or repeat the centrifugation and resuspension steps. (9) The defective interfering virus preparation can be stored in 10% glycerol or DMSO in PBS at -70° C. or a lower temperature. These virus preparations, after reactivation at room temperature are used for vaccination or therapeutic purpose. (10) The virus preparations obtained can be characterized further, such as by morphological examination via electron microscope or density gradient analysis. Further modification of the virus preparation for practical applications, such as vaccination, therapy and storage can be made. For example, aluminum-absorbed virus preparation can be used.
Therapy
An "effective amount" of an antiviral defective interfering particle of the present invention as a drug specifically interfering with the replication or transcription of a non-segmented virus, can be administered to a subject (human or animal). An effective amount is an amount sufficient to alleviate or eliminate the symptoms associated with viral infection. The effective amount for a particular antiviral agent can be determined by one of skill in the art using no more than routine experimentation. Determination of an effective amount may take into account such factors as the weight and/or age of the subject and the selected route for administration.
Antiviral agents can be administered by a variety of methods known in the art. Exemplary modes include oral (e.g. via aerosol), intradermal, intramuscular, intraperitoneal, intravenous, subcutaneous, parental, transdermal and intranasal routes. If necessitated by a particular mode, the gene therapy vector may be encapsulated.
It is specifically contemplated that pharmaceutical compositions may be prepared using the novel HBV-defective interfering particles of the present invention. In such a case, the pharmaceutical composition comprises the novel HBV-defective interfering particles of the present invention and a pharmaceutically acceptable carrier. A person having ordinary skill in this art would readily be able to determine, without undue experimentation, the appropriate dosages and routes of administration of the novel HBV-defective interfering particles of the present invention. Application of HBV-defective interfering particles of the present invention could be used to treat acute hepatitis patients (fulminant hepatitis). These patients have extremely high mortality rate (60-90%) within a very short period (a few days to 2 weeks). There is no effective treatment currently available for fulminant hepatitis.
Treatment of patients with deadly fulminant hepatitis with the HBV-defective interfering particles of the present invention may convert some patients to chronic asymptomatic carriers or chronic active hepatitis. If a patient is converted to chronic asymptomatic carriers, no further treatment of these healthy carriers is necessary. If a patient is converted to chronic active hepatitis, intervention of chronic infection via further treatment, such as interferon-alpha, can be considered. In either case, the patient's life expectancy may be prolonged by decades.
In the therapy of patients with deadly fulminant hepatitis with the HBV-defective interfering particles of the present invention, a person having ordinary skill in this art could determine the dosage needed with routine experimentation. Most likely, higher titer of defective interfering particles (such as 10 8 or 10 9 particles in a few c.c. in one shot per patient) will be most effective. The defective interfering virus can be stored in 10% glycerol or DMSO in PBS at a very low temperature. Before injection, the frozen vials of defective interfering viruses can be thawed at room temperature. Intravenous injection may be an optimal route of administration.
Therapy using these HBV-defective interfering particles is not limited to fulminant hepatitis patients; this therapy is useful to treat chronic or acute hepatitis. As long as the titer of the wild type HBV is significantly reduced by the defective interfering viruses, the hosts' immune system will do the rest.
The present invention discloses the presence of defective interfering viruses in humans, which will not be limited to HBV. Two indepentently derived HBV-CID mutants (pDEL85 and pDEL 109) isolated from two different patients (T85 and T109) are the first proof of human defective interfering viruses in natural infections. Thus, the present invention is directed to HBV-defective interfering particles. In addition, HBV defective interfering mutants containing a genetic defect, e.g., a missense mutation or out of frame deletion, in any part of the HBV genome, within or outside the nucleocapsid protein, is also within the scope of the present invention.
The present invention demonstrates the existence of naturally occurring CID mutants that are defective interfering-like particles. However, it is possible that defective interfering particles of HBV or other viruses can be created, e.g., by site-directed mutagenesis. Using such techniques, a person having ordinary skill in this art would be able to prepare or create other human defective interfering viruses or other human defective interfering-HBV viruses having different structural lesions.
Although the infectivity of DEL85 and DEL109 defective interfering-HBV has not been shown directly, a person having ordinary skill in this art would interpret the following data as evidence of their infectivity. First, the protein moiety of these HBV-defective interfering particles, including envelope, core, polymerase and X proteins, is bascially identical to wild type HBV. Further, the deleted core protein is extremely unstable in vivo. Therefore, the nucleocapsid of the defective interfering-HBV is probably made up exclusively from wild type core protein. Second, when the secreted defective interfering-HBV particles were banded on gradient centrifugation, their sedimentation profile was indistinguishable from that of wild type HBV. Wild type HBV produced in tissue culture in this way was infectious (e.g., Shih et al., '89).
In one specific embodiment of the present invention, a novel stable cell line is provided. HBV-defective interfering particles can be rescued by supplying the wild type core protein in a co-transfection assay (FIG. 2). Thus, one can establish a stable cell line by introducing both an HBV-defective interfering plasmid and an expression vector of wild type core protein into the same replication permissive cells, such as the rodent Morris hepatoma cell line (Shih et al., '89) or human hepatoma cell line HepG2 as is well known to those having ordinary skill in this art.
Replication permissive cell lines are not limited to hepatocytes; HBV is hepatotropic. However, one may engineer a heterologous promoter/enhancer element for HBV expression and replication in a non-hepatocyte system. For example, one may use non-hepatocyte systems, such as fibroblast, lymphocyte, Hela, and transgenic animals/plants.
The HBV-defective interfering viruses are not limited to pDEL85 or pDEL109 (FIG. 1) in this patent application. Other HBV-defective interfering viruses, such as, but not limited to, those with a different length of deletion or degree of defective interfering effect, an out-of-frame deletion, within or outside core antigen, can also be prepared by those having ordinary skill in this art.
The SV40 expression vector of wild type HBV core antigen has been constructed (FIG. 2). Different expression vectors, such as those with inducible promoters or more potent promoters, can also be used, as would be well known by those having ordinary skill in this art.
The rescued defective interfering particles can be enveloped and secreted into the tissue culture medium (FIG. 2). The medium can be harvested by methods, such as centrifugation, filtration, PEG precipitation, or passing through columns of anti-surface antibodies; whichever is the most cost-effective.
For the purification of DI viruses, various techniques may be used. For example, DI viruses from conditioned medium (e.g., 24-48 hour incubation) can be harvested in a number of ways. Existing protocols for the purification of the 22 nm HBsAg particles can be modified or adopted to purify the DI virus particles. For example, the following steps in different combination and orders can be used. The efficiency of each step involved in the purification scheme is monitored by examining the deleted core gene DNA fragment via PCR amplification (Example 1). One important caveat is to purify the DI virus preparation without losing the biological activity and infectivity of DI viruses. Therefore, existing protocols for the biochemical purification of HBV surface antigen molecules (a non-life form) is not necessarily the best or even applicable for the biological purification of DI viruses (a life form, especially if it is to be used for treatment of fulminant hepatitis patients).
Centrifugation methodology is described in Example 4. For adsorption onto colloidal silica such as aerosil (which is optional), it is unclear if the DI virus can adsorp to aerosil. If they do, after adsorption and washing, DI virus can be eluted from the silica by warm borate buffer. This step is optional since centrifugation steps described above might he sufficient to reduce the process volume, enrich DI virus particles and remove debris and serum proteins.
Size exclusion, ion exchange, or hydrophobicity (e.g., butyl agarose or sepharose) chromatography methods can be used if they are more cost-effective , simpler or easier than centrifugation. PEG-precipitation, i.e., the precipitation of viruses using PEG6000 at 4° C. for a period of hours may also be used.
Immunoaffinity chromatography, e.g., using a two column system may also be used. The first column consists of anti-HBV envelope antibody attached to Sepharose and eluted with 3M NASCN.
The second column contains sheep or rabbit anti-bovine serum antibodies designed to remove any residual contamination of bovine serum proteins with the virus preparation. Pepsin treatment at pH2 can be used to remove and degrade contaminants from bovine serum, although dialysis of the DI virus preparation against PBS at 4° C. overnight will be sufficient,
Formulation of the DI virus into a vaccine or therapeutic agent can be accomplished by kepping the DI virus prepagation in sterile PBS. Sterilization can be done by filtration throuhgh a 0.22 μm membrane. Long term storage could include the use of 10% glycerol or DMSO in PES in liquid nitrogen. Short term storage could be in 4° C. or -20° C. It is also possible that glycerol and DMSO are not necessary. Frozen vials of DI viruses should be administerd as soon as they are thawed at room temperature or 37° C. For large scale purpose, tissue culture systems, such as microcarriers, can be tested. Long term storage of defective interfering viruses can be attempted using 10% glycerol or DMSO in the presence of serum and medium (e.g., DMEM) at -70° C. or in liquid nitrogen.
In general, defective interfering-viruses cannot be separated from the helper viruses. The prior art of isolation of defective interfering variants of rhabdoviruses from the infectious helper viruses utilized rate zonal sucrose centrifugation (Huang et al., '66). The present invention discloses a novel approach to make defective interfering virus preparations which does not require the use of a laborious separation step via centrifugation from helper viruses. Most importantly, separation of defective interfering from infectious helper viruses always has a risk of contamination of defective interfering preparation by trace amounts of infectious helper viruses. This approach is much safer than prior art since only the replication defective defective interfering will be rescued and secreted, and there is no chance of contamination of defective interfering preparation by infectious helper viruses.
The following examples are given for the purpose of illustrating various embodiments of the invention and are not meant to limit the present invention in any fashion.
EXAMPLE 1
Preparation of DNA from liver tissues and amplification by PCR and detection of the core deleted variant by Southern blot
For construction of plasmids, pSV2ANeo-HBV dimer containing two head-to-tail copies of HBV genome was used as a wild type HBV expression vector. The fragments from nucleotide 1636 to nucleotide 2688 of pdel85 and pdel109 were amplified from tumor samples, T85 and T109, by PCR with two oligonucleotides. One 30-mer (5'-AAGGGCAAATATTTGGTAAGGTTAGGATAG-3') contains HBV minus-strand DNA aequence from nucleotide 2659 to nucleotide 2688 with a intrinsic SspI cleavage site (underlined). The other primer is a 27-mer (5'-AGAAATATTGCCCAAGGTCTTACATAA-3') containing HBV plus-strand DNA sequence from nucleotide 1636 to nucleotide 1659 with a created SspI cleavage site (underlined). One microgram of tumor DNA and 100 ng of each primer were used in a 10-μl PCR reaction consisting of a denaturing cycle at 94° C. (20 sec) followed by a 40-cycle amplification at 94° C. (1 sec), 47° C.(1 sec), and 72° C. (40 sec). The amplified target sequence (0.9 kb) was subcloned into the pGEM-T vector (purchased from Promega) and secreened for clones containing HBV deleted core sequence by DNA sequencing. The characterized fragment which contains HBV deleted core sequence was purified by digestion with SspI and subsequently swapped for the counterpart of wild type HBV genome carried on a puc12-HBV monomer (HW-1). The dimerization of the core deleted HBV genome was achieved by ligating the EcoRl site spanning fragment (3 kb) of the puc12-HBV deletion monomer back to the downstream EcoRI site of the same plasmid. The resulting dimer constructs, pdel85 and pdel109, were then characterized by restriction enzyme digestion and DNA sequencing was performed for the entire core regions (data not shown).
To construct pSVC, the PCR amplified core fragment from nucleotide 1877 to nucleotide 2463 was digested with restriction enzymes HindIII and SacI and subdloned into the HindIII and SacI sites of the parental plasmid pGCE under the control of the SV40 enhancer and early promoter (Pei., 1991). Two oligonucleotides were used for PCR reaction. One 30-mer (5'-AGAAAGCTTAGCTGTGCCTTGGGTGGCTTT-3') contains HBV plus-strand DNA sequence from nucleotide 1877 to nucleotide 1897 with a HindIII cleavage site (underlined). The other primer is also a 30-mer (5'-AGAGAGCTCATACTAACATTGAGATTCCCG-3') containing A SacI cleavage site (underlined). One nanogram of pSV2ANeo-HBV monomer and 100 ng of each primer were used in a 10 μl PCR reaction consisting of a denaturing cycle at 94° C.(20 sec) followed by 40-cycle amplification at 94° C. (1 second), 53° C. (1 second), and 72° C. (40 second).
To construct p1903, site-direct mutagenesis was performed using plasmid RG6 containing a full-length HBV monomer DNA (Roychoudhury, 1990) and a oligonucleotide (5'- -3') which eliminated the ATG translational start codon of the core region. The procedure for site-direct mutagenesis was adapted from that of Kunkel (Kunkel, 1985) and the dimerization of the HBV genome was described elsewhere (Roychoudhury, 1990).
EXAMPLE 2
Cell culture and transfection
The human hepatoma cell line Huh7 was maintained in Dulbecco's modified Eagle's medium (DMEM) with 10% fetal bovine serum at 37° C. in the presence of 5.5% CO 2 . The calcium phosphate transfection procedure was detailed elsewhere (Shih, 1989). Briefly, 10 6 cells per 10-cm dish were transfected with certain amount of assayed DNA plus human genomic DNA to a total amount of 35 μg. Donor DNA was removed at about 6 hours post-transfection, and cells were fed with fresh DMEM containing 10% fetal bovine serum.
EXAMPLE 3
Preparation of intracellular core particles
The procedure used to prepare intracellular core particles was described in detail (Roychoudhury, 1991). At 5 days post-transfection, cells from one 10-cm dish (6×10 6 cells) were lysed at 37° C. (15 minutes) in 1 ml of buffer containing 10 mM Tris hydrochloride (pH 7.5), 1 mM EDTA, 50 mM NaCl, 0.25% Nonidet P-40, and 8% sucrose. The lysate was then spun in a microcentrifuge for 2 minutes, and the supernatant was transfered to another tube. The supernatant was brought to 8 mM CaCl 2 and 6 mM MgCl 2 , followed by digestion with 30 U of micrococcal nuclease and 1 U of DNase I at 37° C. (15 minutes). The crude core particles were then precipitated by adding 330 μl of 26% polyethylene glycol (molecular weight 8000) in 1.5M NaCl and 60 mM EDTA. After incubation for 1 hour at 4° C., the crude core particle preparations were pelleted by spinning in microcentrifuge for 4 minutes.
EXAMPLE 4
Collection of extracellular core particles
Extracellular core particles were collected 5 days post-transfection from a 10-cm dish of 48-hour conditioned media (10 ml). The medium was precleared by spinning at 3,200 rpm for 15 min. in a IECCentra-8 centrifuge. Particles from the clarified medium were pelleted through a 16-ml cushion of 20% sucrose by spinning at 25,000 rpm for 16 hours at 4° C. in a Beckman SW28 rotor.
EXAMPLE 5
Preparation of core associated DNA
The core pellet was resuspended in 100 μl of buffer containing 10 mM Tris (pH 7.5), 8 mM CaCl 2 , and 6 mM MgCl 2 . The suspension was then treated with 30 U of micrococcal nuclease and 1 U of DNase I for 15 minutes at 37° C. Core particles were lysed by the addition of 300 μl of lysis buffer containing 25 mM Tris (pH 7.5), 10 mM EDTA, and 1% SDS in the presence of protinase K at a final concentration of 400 μg/ml. After incubation at 50° C. for 1 hour, DNA was phenol and chloroform extracted and ethanol precipitated.
EXAMPLE 6
Preparation of core associated RNA and total RNA
Briefly, the core pellet was first dissolved in 100 μl of denaturation solution (4M guanidine thiocyanate, 25 mM sodium citrate, 0.5% Sarkosyl, 0.1M 2-mercaptoethanol). Following dissolution, 10 μl of 2M sodium acetate (pH 4.0) and 100 μl of water-saturated phenol were added with mixing of the solution by inversion. Finally, 20 μl of a chloroform-isoamyl alcohol mixture (49:1) was added and vortexed for 30 sec. The whole mixture was kept on ice for 15 minutes and then centrifuged for 15 minutes at 4° C. The resulting aqueous phase was transfered to another tube, and RNA was precipitated by the addition of an equal volume of isopropanol. For isolation of total RNA, cells from a 6-cm dish were lysed in 350 μl of denaturation solution 2 days post-transfection, and the volume of the rest of the solutions were adjusted accordingly.
EXAMPLE 7
Primer extension analysis
A 5'-end-labeled 22-nucleotide synthetic oligonucleotide (nucleotide 1980 to nucleotide 2001) was used as a primer. Approximately 10 5 cpm (0.1 pmol) was lyophilized with half of core-associated RNA isolated from one 10-cm dish. The dried pellet was dissolved in 30 μl of hybridization buffer containing 40 mM PIPES [piperazine-N,N'-bis(2-ethanesulfonic acid)] (pH 6.4), 400 mM NaCl, 1 mM EDTA, 80% formamide. The hybridization mixture were heated up to 85° for 10 minutes and quickly transfered to a water bath at 30° for 2 hours. After annealing, 170 μl of water and 400 μl of ethanol were added for precipitation. The washed and dried pellet was then dissolved in 20 μl of reverse transcription buffer (50 mM Tris hydrochloride [pH 8.5], 8 mM MgCl 2 , 30 mM KCl, 1 mM dithiothreithol, 1 mM of four deoxynucleotide triphosphates, 50 μg of actionmycin D per ml, 10 U of human placental RNase inhibitor) and incubated with 25 U of reverse transcriptase from avian myeloblastosis viruses (Boehringer Mannheim GmbH) at 45° for 90 minutes. The reaction was terminated by the addition of 1 μg of 0.5M EDTA, and the RNA was digested with 1 μg of pancreatic RNase A at 37° C. for 30 minutes. A 100 μl volume of 2.5 mM ammonium acetate was then added, followed by phenallchloroform extraction and ethanol precipitation. The washed and dried pellet was dissolved in 3 μl TE (10 mM Tris hydrochloride [pH 7.5], 1 mM EDTA), and 4 μl of loading buffer (80% formamide, 1 mM EDTA, 0.1% bromophenol blue, 0.1% xylene cyanol) was added. A 3-μl portion of each sample was analysed on a 6% polyacrylamide sequencing gel.
EXAMPLE 8
In vitro translation, CAT assay and Southern (DNA) and Northern (RNA) analyses
Southern and Northern blot analyses followed standard procedure (Maniatis, 1989). Filters were probed with a vector-free 32 P-labeled full-length HBV DNA fragment (3.1 kb).
EXAMPLE 9
Western (protein) blot analysis and antibodies
Immunoblot procedure was adapted from Harlow and Lane (1988). Cells from one 6-cm dish were lysed at 3 days posttransfection with 150 μl 2× loading buffer (0.5M Tris hydrochloride [pH 6.8], 2% SDS, 5% β-mercaptoethanol, 20% glycerol, and 0.0025% bromophenol blue), and one 25-μl aliquot was subjected to SDS-PAGE electrophoresis before transfering to nitrocellulose (Schleicher and Schuell). The blotted filter was blocked with 2% nonfat milk in PBS for 30 minutes at room temperature. The blocked filter was incubated with primary antibody overnight at 4° C., and then washed 3 times with 5 minutes interval with PBS containing 0.05% Tween 80 (TW80/PBS). Rabbit anticore antiserum was developed by Dr. Lanford (Lanford, 1987) and mouse antiPS-1 antiserum was developed by Dr. Gerlish. After TW80/PBS wash, the blot was rinsed with cold PBS and then incubated with 0.25% glutaradehyde in PBS for 15 minutes at 4° C. After briefly rinsed with cold PBS, the blot was reblocked with the buffer containing 0.2% BSA and 0.1M glycine in PBS (pH 8.5) for 20 minutes at room temperature. Either goat anti-rabbit or goat anti-mouse antiboy conjugated with horseradish peroxidase (BIO-RAD) was applied to the blot and incubated for 2 hours at room temperature. The filter was washed 3 times with TW80/PBS and then developed using ECL kit as recommended by the manufacturer (Amersham).
EXAMPLE 10
Sedimentation and fractionation of virus particles: Surface and e Ag assays
Abbott HBe (rDNA) EIA and Auszyme Monoclonal kits were used for the immunoassay of e and surface antigens according to the manufacturer's procedure (Abbott Laboratory).
EXAMPLE 11
Construction of HBV-CID plasmids
In studies (Hosono et al., '95), HBV-CID mutants were identified in Taiwanese HCC patients T61 and T109. The internal deletion of core antigen of T61 and T109 ranges from around codons 80 to 120. The present invention identified a third CID mutant from patient T85, which contains an even larger deletion (codons 89-136) by extending into the adjacent hotspot mutational domain V.
The deletion-containing HBcAg fragments of T85 and T109 were PCR-amplified and substituted with the normal counterpart of a wild type HBV plasmid (Shih et al., '89). To mimic the circular configuration of HBV genome, the monomeric recombinant chimera between CID and wild type were dimerized in tandem. The tandem homodimer plamids are abbreviated as pDEL85 and pDEL109, respectively. DEL85 deleted HBcAg amino acids 88 to 135 while DEL109 lost amino acids 82 to 122 (FIG. 1A). The construction of these plasmids has been confirmed by DNA sequencing across the recombinant junctions.
EXAMPLE 12
Replication and Packaging Defects of HBV-CID Mutants
To see if the CID mutants are viable by itself, either DEL85 or DEL109 alone were transfected into a human hepatoma cell line Huh7. As shown in FIG. 1B, both mutants are replication defective by Southern blot analysis. The deficiency in DNA synthesis is due to their defect in RNA encapsidation as indicated by primer extension analysis using encapsidated pregenomic RNA (FIG. 1C). Productive pregenomic RNA encapsidation requires at least three different viral components: nucleocapsid protein, polymerase and the 3.5 kb pre-genomic RNA.
To identify the defect of CID mutants in encapsidation, the steady state level of the pregenomic RNA was first examined by Northern blot analysis (FIG. 1D). No significant difference between wild type and CID mutants was detected. The deletion endpoints of a-DEL109 is 15 amino acids upstream from the translational initiation codon (AUG) of polymerase (Hosono et al., '95) while the deletion endpoint of DEL85 is exactly next to the AUG initiation codon of polymerase (nucleotide sequence data not shown; see FIG. 7B for amino acid sequence). Therefore, the open reading frames of polymerase in both CID mutants are not directly affected by the core internal deletions.
To measure the low level expression of polymerase, a fusion construct was engineered between polymerase and the reporter gene of chloramphenicol acetyltransferase (CAT). Again, no appreciable difference of CAT activities between CID mutants and wild type was detected (FIG. 1E). Finally, the production of nucleocapsid proteins from either wild type or CID mutants was examined. The defect in RNA encapsidation of CID mutants is correlated with the absence of a 22 kD or lower molecular weight HBcAg protein by immunoblot analysis (FIG. 1F).
EXAMPLE 13
CID mutants are Rescuable by Wild Type Core Protein
The fact that these replication-defective CID mutants can be detected in patients by PCR suggested that they might be able to survive in the presence of other HBVs. CID mutants were cotransfected with a wild type HBcAg expression vector. Both CID mutants can be rescued to at least 80% level of wild type replication activity (FIG. 2A). These rescued CID mutants can also be secreted into the medium (FIG. 2B). The sedimentation profile of these rescued and secreted CID viral particles on gradient centrifugation by Southern blot analysis was almost indistinguishable from wild type in the Dane particle fractions (FIGS. 4C and D). The presence of the core gene deletion in the rescued and secreted Dane particle fractions was confirmed by PCR amplification (data not shown).
EXAMPLE 14
Interference and Enrichment
As shown in FIG. 3A, when increasing amounts of CID mutants were cotransfected with wild type HBV, the replication activity of HBV remains more or less constant by Southern blot analysis using the full-length HBV DNA probe. However, the relaxed circle form of HBV replicative intermediate purified from cotransfected culture reproducibly migrates slightly faster than that from cultures transfected with wild type DNA alone.
The same filter of FIG. 3A was washed and reprobed with a wild type-specific DNA fragment from within the internally deleted region of HBcAg gene (FIG. 3B). This probe should not hybridize with the CID mutant DNAs. In contrast to the results in FIG. 3A, in the presence of equal amount of CID mutant DNAs, wild type specific DNA replication was reduced by approximately 7 fold in the case of DEL85 and approximately 3 fold by DEL109. As a control for nonspecific effects, such as squelching of limiting amount of cellular transcription factors, a packaging and replication defective HBV mutant TGAGC was included for comparison (Yuan et al., '95). No apparent reduction of wild type replication was observed by cotransfection with mutant TGAGC (FIG. 3B). To directly demonstrate that the signals of HBV replication in cotransfection experiment in FIG. 3A was largely due to the replication of CID mutants, the same filter was probed with mixtured probes specific for DEL85 and DEL109. Consistent results were obtained (FIG. 3C). Taken together, FIGS. 3A-C indicated that while the CID mutant is increased in proportion, wild type replication is greatly reduced.
To show that the defective interfering-like behavior of HBV-CID mutants was not idiosyncratic to Huh7 cell line, the same experiment were repeated using another replication-permissive human hepatoblastoma cell line HepG2. Similar results were obtained in HepG2 system although the defective interfering effect appears to be even stronger in HepG2 than Huh7, as indicated by a 10 to 16 fold reduction in wild type replication (FIG. 3D). This defective interfering phenomenon, including interference of wild type and enrichment of CID mutants was also evident when extracellular HBV particles was examined using the full-length HBV probe (FIG. 3E) or wild type-specific probe (FIG. 3F). In general, the defective interfering effect of DEL85 was more potent than that of DEL109 (FIG. 3B and 3D). FIG. 3G shows a cartoon illustration of the wild type-specific and DEL- specific probes used.
EXAMPLE 15
PCR analysis before and after transfection
To confirm the results obtained by Southern blot analysis, a PCR assay was used to measure directly the relative population of wild type helper virus and CID variants in the cotransfection experiment. When a mixture of the donor DNAs (pWT and pDEL85) in the 2:1 dose ratio was used in the PCR assay, the wild type-specific DNA fragments exhibited similar intensity to that of the DEL85 deleted fragment after amplification (FIG. 4, top). This is probably because the shorter (deleted) DNA fragments tend to be amplified favorably during PCR. However, the relative intensity between amplified wild type and mutant DEL85 DNA fragments shifted from 1:1 (before cotransfection) to 1:5 (after cotransfection), suggesting the preferential de novo replication of CID variants over wild type HBV in vivo (FIG. 4, bottom).
EXAMPLE 15
Specific vs. Nonspecific Interference
Based on the enrichment phenomenon of CID mutants, one would conclude that the interference on wild type is probably not caused by a nonspecific effect, such as different degree of resistance to cytotoxicity or defective interfering-induced interferon-like soluble factors to which wild type is perhaps more sensitive. Consistent with this, FIG. 5A showed that the conditioned media of CID mutant-transfected culture did not confer any apparent interference effect when applied to the wild type HBV transfected culture. Furthermore, when duck hepatitis B virus DNA was cotransfected with human CID mutants, no apparent decrease of duck hepatitis virus DNA replication was observed (FIG. 5B). The DNA probe of duck hepatitis virus does not cross react with human HBV even at highly relaxed stringency (data not shown). Therefore, the interference phenomenon of HBV-CID appears to be homotypic and species-specific. In summary, as characterized above, the properties of CID mutants seem to fit well with the conventional definition of defective interfering particles: deleted genome, replication defective, rescuability by helper viruses, and enrichment of themselves at the expense of helper viruses (Huang & Baltimore, '70).
EXAMPLE 16
Highly Unstable CID-HBcAg and e Antigen
One mechanism for the interference phenomenon of HBV CID mutants is the dominant negative effect on the wild type HBV mediated through the deleted core protein. The existence of the internally deleted core antigen was determined by immunoblot analysis using a polyclonal anti-HBcAg antibody. Despite the use of different anti-HBcAg antibodies, no core protein was detected from the CID mutant (FIG. 1F). This negative result could be due to a number of possibilities, such as loss of a dominant antibody recognition site and/or instability of the produced mutant core protein.
To differentiate among these possibilities both the deleted and wild type core proteins, were tagged with a flu epitope. As shown in FIG. 6, wild type core-flu fusion protein can be detected by either anti-core (FIG. 6A) or anti-flu antibodies (FIG. 6B). In contrast, CID core-flu fusion proteins cannot be detected by either antibodies, despite the stable expression of CID mutant core-flu mRNAs from plasmids pSV85flu and pSV109flu (FIG. 6C). Therefore, the loss of a dominant anti-core antibody recognition site alone is a less likely explanation for the absence of CID-specific core protein.
However, using an in vitro transcription and translation assay, CID mutant core protein with a reduced molecular weight can be expressed in vitro, albeit with a lower intensity relative to the wild type core protein. Furthermore, when the ATG initiation codon of the CID core protein is ablated by changing into ATA, no translated protein was observed (FIG. 6D). When the wild type and deleted core proteins were analyzed under non-denaturing condition, CID core proteins appeared to homopolymerize more readily than wild type core protein (FIG. 6E). Taken together, these results are consistent with the interpretation that the CID core protein is highly unstable in vivo and in vitro.
The core antigen is structurally related to HBV e antigen. Because core and e antigens share the same open reading frame, the CID deletion not only creates an unstable core protein, but also an unstable e antigen. No production of e antigen from CID variants were detected using Abbott EIA kit. Therefore, CID mutant DEL85 and DEL109 exhibited an e antigen negative phenotype (data not shown). Absence of e antigen has been proposed to be associated with fulminant hepatitis (Shafritz et al., '91). The biological function of e antigen is not fully understood; nontheless, it may be involved in HBV pathogenesis (Milich et al '90; Carman et al., '89).
EXAMPLE 17
No Dominant Negative Effect of CID-Core Antigen
Dominant negative mutants of hepadnaviruses have been artificially created by fusing the core and surface genes (Scaglioni et al., '94), or by deleting part of the DHBV core antigen (Horwich et al., '90). One essential feature of the defective interfering viruses is their enrichment behavior. Although the dominant negative mutants can interfere with the replication of wild type, they are not able to enrich themselves at the expense of the wild type. Therefore, it is unlikely that the defective interfering phenomenon is mediated through a dominant negative effect.
To demonstrate whether the defective interfering phenomenon could be (solely) caused by the deleted core protein via a dominant negative effect, wild type HBV was cotransfected with an expression vector of CID mutant core protein (pSV109). As a control, a derivative of pSV109 with an ablated initiation codon changing from ATG to ATA were also cotransfected in parallel wild type and pSV109ATA. No apparent reduction in wild type HBV replication was observed when pSV109 was used (FIG. 6F). This result is consistent with the aforementioned high instability of CID mutant core protein in vivo. In summary, the interference phenomenon of CID mutant does not appear to be caused by any dominant negative effect through the deleted core protein.
EXAMPLE 18
Cyclic Interactions in vivo between Helper Virus and defective interfering Particles
Although the DEL85 and DEL109 constructs are faithful facsimiles of the original CID variants isolated from human patients in nature, these studies were based on tissue culture cell lines. To see if there is any dynamic equilibrium between the defective interfering and helper HBV in nature, HBV populations were examined in serially collected serum samples of a chronic active hepatitis patient. This patient (KP) died of HBV-related liver cancer and was followed up longitudinally from 1989 to 1993 at Fox Chase Cancer Center. Except for the samples collected in February 1992 and June 1993, HBV DNA can be detected in the sera of this patient via PCR (FIG. 7A). The relative abundance of helper and defective interfering viruses appears to be variable at different times. For example, only wild type, but not defective interfering viruses, were detectable in February 1990 and December 1993. However, both wild type and defective interfering mutations were detected in December 1989 and February, 1991.
To confirm the PCR data, DNA sequencing of 2-4 independent HBV clones from serum samples collected at different time points was performed. Two different CID mutants in FIG. 7B (clone 3 from December 1989 and clone 4 from February 1991) bears identical deletion endpoints to those of mutant DEL85. An out-of-frame internal deletion of core protein was also identified from clone 4 of December 1989. There is no correlation between the populations of either defective interfering or helper viruses and the clinical marker of liver injury (ALT) (FIG. 7A). Unlike the helper viruses, CID mutants, including DEL85, clone 3 of Dec/89, and clone 4 of Dec/93, did not accumulate any putative immune escape mutations at codon 13 within the hotspot mutational domain I. Nor did they accumulate any hotspot mutation at codon 151 of domain VI and codon 182 of domain VII (FIG. 7B; Hosono et al., '95). The wax and wane of defective interfering HBV from time to time was reminicent of the reported cycling phenomenon between defective interfering and helper viruses in other viral systems using tissue culture and animal models.
Despite the ubiquity and prevalence of HBV CID mutants in various hepatitis B carriers, the biological significance of CID mutants remain unclear. Two different CID mutants (DEL85 and DEL109) isolated from two different patients using two different hepatoma cell lines (Huh7 and HepG2) were characterized. CID mutants behave like defective interfering particles: deleted genome, replication defective, rescuable by standard helper virus, interfering with standard virus and enrichment of defective interfering particles. The interference effect is 3-16 fold in a single cycle, depending on the specific defective interfering virus per se, the host cell lines, and the relative dose of defective interfering and helper viruses. This effect could in theory become dramatized exponentially after a few serial cycles of infection.
As a DNA virus, hepadnaviruses can replicate through a pregenomic RNA intermediate (Summers & Mason, '82). Thus, hepadnaviruses have a unique phylogenetic status between DNA and RNA viruses. Although defective interfering viruses have been found in tissue culture or animal model of DNA and RNA viruses, the prevalent CID mutants of HBV characterized here are the first example of defective interfering-like particles in this hepadnaviridae family. To date, there have been no reports of defective interfering particles found in human infections in nature (Holland '87 and '91).
The conventional approach of defective interfering particles relies on the plaque assay via infection in tissue culture or passage in animal models. Although in vitro infection assay of HBV has been reported, it is still not generally adopted by most HBV research laboratories. The present invention demonstrates a new approach to defective interfering studies without relying on the conventional infection and plaque assays.
EXAMPLE 19
Mechanism of Occurrence of Core Internal Deletion
The occurrence of CID mutants is not due to the reverse transcription of spliced HBV-specific RNA (Terre '91). First, none of the deletional endpoints have the consensus sequences required for RNA splice donor and acceptor sites (i.e., GT and AG rule). Second, the deletion end points are variable in positions (Okamoto et al., 87; Wakita et al., '91; Ackrill et al., '93). Third, the deletion endpoints do not coincide with any of the reported splice junctions in HBV literature (Chen et al., '89). There is a 2-3 nucleotide junctional homology at both ends of internal deletion of several CID variants. This result is more in line with a mechanism of intramolecular illegitimate recombination (Shih et al., '87).
EXAMPLE 20
Mechanism(s) of Enrichment and Interference
One mechanism of the defective interfering phenomenon is the induced production of interferon by defective interfering particles, as was reported in influenza viruses. As demonstrated herein, the defective interfering phenomenon in HBV is not due to nonspecific cytotoxicity, nor is it due to production of interferon or other unknown soluble factors (FIGS. 5A and 5B).
It remains unclear if the mechanisms of HBV-defective interfering enrichment and interference are related or independent. If they are independent, they may be caused by two or more separate mutations or by a single pleiotropic mutation. In the constructions of plasmids pDEL85 and pDEL109, a 1 kb SspI fragment of CID mutants was amplified and subdloned into the backbone of a wild type HBV plasdmid. Therefore, the defective interfering phenotype of CID mutants is encoded entirely within this 1 kb fragment. When the amino acid sequences of this 1 kb insert of DEL85 and DEL109 were compared, the only common mutations between these two different CID mutants was the core internal deletion as well as an A-to-T change and a G-to-A change at nucleotide 1762 and 1764 respectively (referred to as TA mutations). The TA mutations occurring within the basal core promoter/X gene have been found in patients with chronic hepatitis, fulminant hepatitis and hepatocellular carcinomas. TA mutants are replication competent and might replicate slightly better than wild type (Buckwold et al., '96). The modest effect of TA mutation on the replication of HBV cannot explain for the interference of up to a 16 fold effect.
When the deleted core protein alone was provided to the wild type HBV, no apparent negative effect on the replication of wild type HBV was observed (FIG. 6F). There is also no negative effect from the CID mutant at the level of transcription. Taken together, the defective interfering phenotype of HBV CID mutants appears to be caused mainly by a single deletional mutation and no detectable negative effect is involved in the interference. Interference of HBV-CID mutants may be secondary to enrichment.
EXAMPLE 21
Multiple Immune Escape Mutations and defective interfering-Immune Shelter Hypothesis
As described earlier, the deleted core protein is highly unstable in vivo (FIG. 6). This result led to the hypothesis that the deleted core protein often gets degraded soon after synthesis without ever being presented to the immune system as a target antigen. This hypothesis is supported by the previous observation that CID mutants T61 and T109, accumulated no mutation in the other known hotspot mutational domains of core antigen (Hosono et al., '95). By contrast, late stage helper virus variants generally accumulate an average of 4 mutational domains in HBcAg (Hosono et al., '95). This result is reinforced by the present invention that three additional clones of CID mutants from two different patients also contain no mutation in other mutational domains (FIG. 7B). Taken together, 5 different CID clones from 4 different patients accumulated a total of zero mutations, instead of the predicted total of 12 mutations, in the other hotspot mutational domains of HBcAg. Therefore, the deleted core proteins of CID mutants appear to ignore the immune selective pressure and can be considered as "immunologically anergic".
When lymphocytic choriomeningitis virus (LCMV) was injected into transgenic mice bearing a LCMV-specific T cell receptor (TCR), LCMV variants containing immune escape mutations within the cytotoxic T lymphocyte (CTL) epitope were found to prevail from evolution. Although immune escape mutations of LCMV were possible in this artificial animal model which bears a monospecific TCR, it is unclear how could multiple independent immune escape mutations occur simultaneously in the field within multiple epitopes of multiple viral antigens concurrently under immune surveillance. For example, there are an average of 4 different putative immune escape mutations within different HLA-class II-restricted T cell epitopes of HBV core antigen (Hosono et al., '95). Similarly, at least four different mutations at four topographically distinct antibody recognition sites on the three-dimentional structure of the influenza haemagglutinin have been proposed as a requirement for the production of new epidemic strains between 1968 and 1975 (Wiley et al., '81; Caton et al., '82). The internal deletion of CID mutants only deleted one, sometimes two, of the four potentially important T cell epitopes (FIG. 7B; Jung et al., '95; Hosono et al., '95; Tsai et al., '96). Since the occurrence of mutations is always a rare event, to date, it is unknown whether the statistically unlikely occurrence of multiple immune escape mutations of viruses could actually occur in nature under the host's multispecific immune system.
To look for a similar phenomenon in natural HBV infections, serum samples were collectedfrom three chronic carriers during a longitudinal study and found the deleted core mutation in HBV by PCR. The deletions in these DNA fragments were found to occur in the central part of HbcAg via sequencing. Furthermore, in the case of a Korean patient, the same CID variant population appeared to predominate during the 4 year follow-up period. The total HBV DNA titer was seen to fluctuate over time and somtimes even dropped to a very low or undetectable level (FIG. 7C). Interestingly, the relative abundance of CID variants and helper viruses also appeared to vary over time. The relative intensity of helper virus-specific DNA was often greater than that of the CID variant DNA. However, at some time points, the reverse was observed (FIG. 7C, in 1991; FIG. 7D, in 1989). It should be mentioned here that in FIGS. 7C, and 4D, the absolute amount of the PCR product was not measured. Rather, the ratios between the wild type and CID variant populations at different time points were compared. Therefore, the quantity of each band is internally controlled by the other band.
These results indicate that a dynamic equilibrium could exist between the CID and helper HBV in vivo. This observed waxing and waning of DI-like and helper viruses are reminiscent of the cycling phenomenon reported in other DI viral systems, such as rabies and vesicular stomatitis virus (VSV) (21, 29).
Defective interfering particles were often found in cultures persistently infected with virulent viruses. The attenuating effect of defective interfering particles on the titer of helper viruses should provide the parental helper virus an advantage in establishing or maintaining persistent infection. Since HBV is not directly cytopathic to hepatocytes, the symbiotic relationship between defective interfering and helper HBV is different from previously reported defective interfering particles in other viruses (Holland '87). The present invention indicates that defective interfering particles could contribute to latency and chronicity of HBV infection by attenuating the replication of wild type helper viruses (FIGS. 3C, 3E, 3F) and subsequently decreasing the total amount of loaded wild type antigens to a subclinical level (which is) below the detection threshold of the hosts' immune surveillance. This hypothesis is supported by the finding that CID mutants are rarely (or never) found in acute hepatitis patients (Ehata et al., '93; Aye et al., '94), but are found in 100% of asymptomatic HBV carriers (Okamoto et al., '87), 64% of Japanese chronic hepatitis patients (Wakita et al., '91), 100% of HBV-infected kidney transplantation patients (Gunther et al., '95), and 75% of European Caucasian chronic active hepatitis (Ackrill et al., '93); however, in only 7% of chronic hepatitis B patients in Hongkong (Akarca and Lok '95). The discrepancy of the defective interfering prevalence between Hongkong and other places is unclear. It is possible that some of the HBV defective interfering viruses do not have deletion in HBcAg.
EXAMPLE 22
The in vivo cycling of variants in the Korean patient happens to contain a predominant CID variant population which shares an identical deletion with DEL85 and two other CID variants independently identified by two other research groups (see FIG. 8). Despite the identical CID deletion in the core region, DEL85 and the CID variants in the Korean patient are different from each other in the non-deleted portion by a total of 6 amino acids (data not shown). Thus, PCR contamination between DEL85 and the Korean sample is highly unlikely. In summary, the behavior of the cloned variant DEL85 probably can be directly related to the in vivo cycling data. Finally, according to the definition of cycling, the ratio between helper and DI particles does not remain constant. Depending on the timing of the sampling, the ratio between helper and DI viruses is expected to vary.
FIG. 9 shows the transfection of DEL85 plasmid DNA with a wild type core protein expression vector (pSVC) at a 10:1 DNA mass ratio into rat Morris hepatoma cell line 7777 or Q7. A total of 30 neomycin resistant colonies were selected from the transfected culture. After screening for active HBV DNA replication by Southern blot analysis, two independent clones (designated as DEL85/Q7 clones 1-15-1 and 1-12-2), producing the putative DEL85 HBV replication. Thus, the present invention demonstrates that one can produce a stable cell line producing defective interfering particles of viral origin. Furthermore, one can now purify defective interfering particles to homogeneity that are free from contamination of the replication competent helper virus.
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Any patents or publications mentioned in this specification are indicative of the levels of those skilled in the art to which the invention pertains. These patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.
One skilled in the art will readily appreciate that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. The present examples along with the methods, procedures, treatments, molecules, and specific compounds described herein are presently representative of preferred embodiments, are exemplary, and are not intended as limitations on the scope of the invention. Changes therein and other uses will occur to those skilled in the art which are encompassed within the spirit of the invention as defined by the scope of the claims.
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The present invention provides a composition of matter comprising a defective interfering virus particle, wherein said particle naturally occurs in a human infection and wherein said particles has a naturally occurring core antigen internal deletion. Provided is a pharmaceutical composition, comprising defective interfering virus particle and a pharmaceutically acceptable carrier. Provided is a method for preparing defective interfering virus, comprising the steps of: (1) introduce a defective interfering virus and a complementing plasmid expressing a wild type virus core antigen and optionally containing a drug resistance gene, into a recipient cell; (2) selecting for stably transfected colonies; (3) growing the drug resistant cells and screening for the production of virus DNA replication; and (4) collecting defective interfering virus particles from the medium. Further provided is a vaccine, comprising a defective interfering virus particle.
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PRIORITY INFORMATION
This application claims the benefit of U.S. Provisional Application No. 60/432,418 on Dec. 12, 2002.
FIELD OF THE INVENTION
The field of this invention relates to a method of cleaning a well bore with a tubular wiper and valve arrangement.
BACKGROUND OF THE INVENTION
During the process of drilling and completing a well it is often desirable to remove all solid materials from the mud system in the well bore as well as removal of cement, metal and other materials which may cling to the wall of the tubular or in the case of a deviated well be laying on the side or bottom of the partially horizontal tubular. In many cases it is also desirable to change out the mud system in the well bore to a completion fluid, which is free of solids.
Currently this process is accomplished by running a tubular (commonly called a “work string”) to or near the bottom of the well. Then circulating fluid through or down this work string and into the annulus between the tubular and well bore. Circulation is accomplished by pumping fluid down the work string and back to the surface through the annulus between the work string and casing.
To assist in these process mechanical devices such as casing scrapers and brushes are attached near the bottom of the work string to remove the solids that may cling to the casing such as cement, formation debris or metal particles.
Circulation to remove the solids requires turbulent flow. In most if not all cases sufficient pump capacity is not available to accomplish the required flow rates. The flow area of the annulus is no less than 3 times and more often 5 to 10 times that of the work string. Therefore the flow rate required to maintain turbulent flow in the annulus is at least 3 times that required in the work string. By causing the solid laden fluid to flow to the surface through the work string the solids are more likely to be removed from the well due to the higher velocity fluid stream in the work string. This is particularly true in deviated wells where it is known that the mud system will “channel” and not cover the entire annular area. In these cases the solids remain in the well bore and can cause failure of packers, valves, etc. that are run in the well as a part of the completion process. These solids can also cause formation damage that prevents the well from producing at its maximum or prevents injection into the formation.
It is therefore evident to those familiar with these processes that it is desirable to move the solids to the surface by forcing them into the highest velocity flow available this being the work string.
The newest known device that represent this type of well bore clean out method is from Baker Oil Tools titled “The Well Bore Custodian” These devices are run and pulled from the well bore to remove the solids from the casing wall and place them in the mud system. Most devices require circulation to remove the solids; recognizing that circulation alone can not remove the solids, Bakers' device attempts to remove the solids by filtering them from the mud system. This device relies on the filtering system to retain the solids until the device is removed from the well. As seen in the prior art, filtering devices have been tried in the past and found not to remove all of the solids.
In the past, as illustrated in several patents, there have been a variety of tools and techniques used to remove debris. U.S. Pat. No. 2,782,860 shows the use of reverse circulation into a pickup tube held by a packer inside a tubular. Several devices involve pulling vacuum on the tubular to suck fluid and debris into it. Some examples are U.S. Pat. Nos. 3,775,805; 4,630,691; 5,269,384; 5,318,128; 3,958,651 and 5,033,545 (fluid jet creates a vacuum). U.S. Pat. No. 5,402,850 uses a seal and crossover to force fluid with debris into the annulus around the tubular string for the trip to the surface. Other techniques involve reverse flow into the tubing string, such as: U.S. Pat. Nos. 4,944,348 and 5,069,286. Also of interest are U.S. Pat. Nos. 5,562,159 and 5,718,289.
SUMMARY OF THE INVENTION
Multiple embodiments of well bore clean out systems are disclosed. These embodiments remove the solids from the well bore annulus as soon as they are encountered and places them into the tubular being run in the well bore. This will place the solids into the inside of the work string where higher velocities will move the solids to the surface where they can be separated from the mud system. This is made practical by newly patented devices such as those disclosed in patents U.S. Pat. Nos. 6,390,190 and 6,415,862.
The system consists of at least one circulator assembly having a port below a packer cup to divert fluid from the annulus into the work string as the work string is being lowered into the well bore. This system can consist of a circulator assembly for each casing size in the well being cleaned, in other words, multiple circulator devices on one work string with porting to control the flow of fluids.
Valve assemblies are also be disclosed which selectively open and/or close to direct flow either into the tubular or around the packer cup. This valve assembly provides a path for fluid around the packer cup when the work string and circulator is removed from the well.
A method comprises of directing the mud above any mechanical cleaning devices and through a port below the packer cup into the tubular immediately below the packer cup.
A valve assembly is disclosed that selectively opens the very bottom of the work string to allow reverse circulation to the bottom of the work string to thoroughly clean the well bore prior to removing any one of the assemblies from the well bore.
An arrangement of packer cups is disclosed that assures that annulus fluid between circulators in different casing strings will be directed into the work string. In addition, a process comprises removing solids from the fluid system and casing wall.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a well showing the apparatus positioned in a well having a single casing.
FIG. 2 is a sectional view of a well having a casing and liner of different sizes showing different sizes of the apparatus positioned in each of the casing string and liner.
FIGS. 3 and 3A are a sectional view of a mechanically operated apparatus being run into a well showing the port opened and a cup seal to force the fluid in the annulus into the inside of the apparatus. This view also shows a plug in the lower end of the apparatus to force all fluid in the well below the apparatus into the inside of the apparatus.
FIGS. 4 and 4A are a sectional view of the apparatus in FIG. 3 showing the port closed so that pressure may be applied to the inside of the apparatus to force the plug out of the apparatus.
FIGS. 5 and 5A are a sectional view of the apparatus in FIG. 4 showing the port closed and a passage opened under the cup seal to allow communication of multiple annuli above and below the cup seal. This view also shows a plug in the lower end of the apparatus to force all fluid in the well below the apparatus into the inside of the apparatus.
FIG. 6 is a partial sectional view showing detail of the upper latch shown in the apparatus in FIG. 3 .
FIG. 6 a is an external view of FIG. 6 .
FIGS. 7 and 7A are a sectional view of a hydraulically operated apparatus being run into a well showing the port opened and a cup seal to force the fluid in the annulus into the inside of the apparatus. For simplicity, this view also shows the plug in the lower end of the apparatus removed.
FIGS. 8 and 8A are a sectional view of the apparatus in FIG. 6 showing the port closed and a passage opened under the cup seal to allow communication of the annulus' above and below the cup seal.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , an embodiment A is illustrated that mounts a seal 10 to the work string 12 . Seal 10 can be any one of a variety of styles but a downwardly oriented cup seal is preferred. Not shown in FIG. 1 is the top end of the work string 12 that is connected to a device described in U.S. Pat. Nos. 3,390,190 or 6,415,862 or another surface mounted device that can connect the top of the work string 12 to separation equipment so the debris can be removed prior to the fluid returning to the mud pit. While the seal 10 is advanced downhole, it cleans the debris from the inner wall 14 of the casing 16 . Fluid in the annular space 18 below seal 10 is forced into the work string 12 , through ports 20 . Any suspended debris or debris scraped from the inner wall 14 goes into the work string 12 as a result of advancement of seal 10 . Annulus 2 above seal 10 can have fluid added into it to compensate for the downhole movement of seal 10 and to prevent high pressure from forming across seal 10 , which could retard the further advance of the apparatus A. The displaced fluid and debris that gets into the work string 12 will be directed through a connection apparatus of the type described in U.S. Pat. Nos. 6,390,190 or 6,415,862 or another device into surface separation equipment of known design (not shown) so that the screened fluid can be returned to the mud pit for future use.
Also shown are ports 30 and 31 , which can be selectively opened or closed with ports 20 or conversely closed or opened to allow circulation or reverse circulation around seal 10 at any time during the deployment of apparatus A. The importance and operation of these ports will be more fully described later.
Not illustrated are mechanical devices such as brushes and casing scrapers which may be placed below apparatus A to facilitate removal of solids from the casing wall 14
FIG. 2 adds a second apparatus A′ to the assembly shown in FIG. 1 for deployment in wells that have more than one casing size. Illustrated is apparatus A being deployed into casing 16 on work string 12 while apparatus A′ is deployed into liner 16 ′ on work string 12 ′. The transition from casing 16 to liner 16 ′ is shown by use of a seal and anchor system 3 which is often a liner hanger.
Apparatus A will capture fluid and solids in annulus 18 while apparatus A′ will capture fluid and solids in annulus 18 ′.
It is understood by those familiar with the art that apparatus A will be attached to a work string 12 which will be a length to position apparatus A near the liner hanger 3 , while the length of the work string 12 ′ will be sufficient to place apparatus A′ near the depth of the liner 16 ′.
Also shown are ports 30 , 30 ′, 31 and 31 ′, which can be selectively opened or closed with ports 20 and 20 ′ or conversely closed or opened to allow circulation or reverse circulation around seals 10 and 10 ′ at any time during the deployment of apparatus A and A′. The importance and operation of these ports will be more fully described later.
Again not illustrated are mechanical devices such as brushes and casing scrapers may be used below apparatus A and A′ to facilitate removal of solids from the casing walls 14 and 14 ′.
FIGS. 3 and 3A show one of the preferred embodiments being run into the well casing 16 . The top sub 32 of the apparatus is threaded to the work string 12 . The top sub 32 is threaded to a mandrel 33 , which runs through the apparatus and terminates in a threaded connection to the bottom sub 41 . The top sub 32 and bottom sub 41 are sealed at the mandrel 33 connection with seals 42 and 45 respectively.
A sleeve 11 is threaded to sleeve 35 . These sleeves have mounted on their exterior, cup seals 10 and 22 , which are supported by thimbles 10 B and 22 B. Though both cup seals, in FIG. 2 , are shown facing downward it is apparent either of these seals can be positioned so that at lease one is facing upward. This can be important if circulation around the exterior of the seals is not wanted or if the fluid pressure in the annulus above the seals is higher than the pressure of fluid below the seals.
These cup seals 10 and 22 are held firmly to the sleeves 11 and 35 by use of the threaded connection 54 between sleeves 11 and 35 so that rotation of mandrel 33 will not rotate sleeve 11 or 35 . The cup seals 10 and 22 are also separated by use of a cup sleeve 10 A.
Sleeves 11 and 35 are held in an upward position and prevented from rotating by frictional forces between the cups 10 and 22 and the casing wall 14 . As the work string 12 is lowered the mandrel 33 will be urged downward with respect to the cups 10 and 22 until the sleeve 35 shoulders on the lower end 56 of the top sub 32 .
Should it be anticipated that fluids of a higher pressure may be above the upper cup (one of the cup seals will then be facing upward), the sleeves 11 and 35 may be held in this upward position by threaded fingers 58 on collet 15 ( FIG. 6 ) which is mounded to the mandrel 33 and has threaded fingers 58 ( FIG. 6A ) engaged into the internal mating threads 15 B ( FIG. 6 ). Should there not be fluids of a higher pressure in the upper annulus there is no need to use the collet 15 .
It is apparent to those familiar with the art that several apparatus may be run into a well on the same work string as indicated in FIG. 2 . Each apparatus would have the same or similar porting arrangement as illustrated in FIGS. 3 , 3 A.
As the apparatus is being run into the casing 16 fluid and solids below the seal 22 flow into ports 23 of the sleeve 35 and into ports 25 in the mandrel 33 then to the interior of the mandrel 18 where they flow to the surface where they flow directly to the mud system or separator and filtering equipment (not shown). Seal 42 located on the mandrel 33 isolates ports 19 and 17 . If this is the lowest apparatus in the work string as shown by apparatus A′ in FIG. 1 , fluid is prevented from entering the lower end of the apparatus by plug 29 which is sealed to the interior of the mandrel 33 at seal 27 and is held in position by shear screws 37 mounted between the plug 29 and mandrel 33 . Plug 29 assures that all flow is through the ports 23 and 25 to maintain the highest velocity possible in annulus 34 . This will prevent solids from collecting and plugging the annulus 34 . This can be important where a casing scraper and or brushes (not shown) are used below the apparatus. The higher flow will help keep the solids moving through and around this equipment. Should this not be the lowest apparatus in the work string, plug 29 would not be used since flow from the lower apparatus' must move through the work string and all apparatus above and plug 29 would prevent this.
A collet 40 is also shown at the lower end of the mandrel 33 the purpose of which will be explained later.
Other devices such as scrapers, brushes, magnets, filters, plug catchers, work string, etc can be attached below the apparatus at threaded connection 49 .
Referring now to FIGS. 4 and 4A , the apparatus is now shown as it would reach its lower most position in the well bore. At this time it would be desirable to reverse circulate the fluid that is in the work string to the surface since this fluid would contain solids swept from the well as the apparatus is deployed. Reverse circulation defined as moving fluid down the annulus 9 and up the inside of the tubular 18 as shown in FIGS. 5 and 5A .
To reverse circulate it is necessary to close the ports 23 and 25 and open port 17 . This is accomplished by picking up on the work string 12 at the surface so that the mandrel 33 moves upward relative to sleeves 11 and 35 . In this position seal 37 will isolate ports 25 from 23 closing them and port 17 moves below seal 42 thereby opening port 17 . This will open an annular space 50 located between sleeves 11 and 35 and mandrel 33 forming a flow path between the upper annulus 9 and the lower annulus 34 to allow fluid above the apparatus to flow below the apparatus freely.
Should the latch 15 be used it would be necessary to rotate the work string 12 as it was being raised to unscrew latch 15 from the mating threads 16 ( FIG. 6 ) in sleeve 11 to allow the mandrel 33 to move upward relative to sleeves 11 and 35 . The same is true for latch 15 ′ except that the work string is rotated as it is being lowered to unscrew latch 15 ′ from mating threads 16 ′ ( FIGS. 4 and 4A ) in sleeve 35 .
It is apparent that latches 15 and 15 ′ are not necessary for operation of the apparatus but serve the purpose of locking the apparatus in one of its two positions.
When the mandrel 33 moves upward until the bottom sub 41 contacts sleeve 35 latch 15 ′ also engages mating latch threads 16 ′ at the lower end of sleeve 35 . This will hold sleeve 35 so that the tool remains in the reversing position. It is understood that the tool can be shifted back to the previous position by lowering the work string 12 while rotating to disengage the latch 15 ′ from its mating threads 16 ′. This will close port 17 and open ports 23 and 25 and engage latch 15 with mating threads 16 as shown in FIG. 6 .
To provide a flow path through the apparatus with ports 23 and 25 closed it is necessary to remove plug 29 . Pressure can now be applied to the interior of the work string 12 . This pressure will apply a force to plug 29 shearing screws 37 thereby releasing plug 29 from mandrel 33 and forcing plug 29 to the bottom of the work well or into a plug catcher sub located at the end of the tool assembly mounted below the apparatus, thus opening the work string.
Referring now to FIGS. 5 and 5A , the apparatus is now shown in the reverse circulating position. Fluid can now be pumped into annulus 46 (at the surface) through port 17 , through the annular area 50 between mandrel 33 and sleeves 11 and 35 , out port 19 through annulus 34 then into the interior of the tool string 18 back to the surface. Reverse circulating will completely flush all fluid from the well bore replacing it with fluid that is pumped into the annulus at the surface. Again it is understood that there can be other assemblies below the apparatus.
The arrangement of the sleeves 11 and 35 along with the friction of the cup seals 10 and 22 with the casing 16 provides a method of shifting the tool from the run in position to the reversing position at will.
In addition the use of the latches 15 and 15 ′ with mating threads 16 and 16 ′ in sleeves 11 and 35 provides a method of not only shifting from one position to the other but locking the apparatus in either of the positions at will.
Referring again to FIG. 2 , should this be the upper assembly A in a tool string such that the fluid moving through the annulus 9 , 9 A and 28 will progress to the bottom assembly A′ then into the interior of the work string 12 .
Referring now to FIGS. 7 and 7A , another embodiment is shown with a top sub 51 attached to the work string 12 . Inside the top sub 51 is a sleeve 52 sealed in the top sub 51 by seals 53 and 54 . A shifting sleeve 55 is located inside the sleeve 52 and is sealed in the sleeve 52 by seals 56 and 57 . The shifting sleeve 55 is also secured to the sleeve 52 and by shear screws 77 . Annulus pressure is vented through port 60 to an annular space 61 between top sub 51 and sleeve 52 , this pressure is then vented to the annular space 63 through port 62 where it operates on surface 59 of shifting sleeve 55 .
This upper portion of the apparatus forms a hydraulic system with pressure inside the work string 12 operating on the upper portion of the shifting sleeve 55 at surface 58 and pressure in the annulus 9 working on the lower side of the shifting sleeve at surface 59 .
Top sub 51 is attached to mandrel 64 . A number of cup seals 65 , 66 , and 67 are mounted on mandrel 64 and supported by thimbles 68 , 69 and 70 and held in place by cup spacers 71 and 72 while being secured to the mandrel by cup sleeve 73 . The cup seals, thimbles, cup spacers and cup sleeve components are secured by the bottom sub 74 , which is connected to the lower end of the mandrel 51 .
If this is the lower apparatus such as A′ in FIG. 2 a plug 29 can be secured to the bottom sub 74 by shear screws 37 . Seal 27 also seals the plug 29 inside the bottom sub 74 .
Other devices such as scrapers, brushes, magnets, filters plug catcher subs etc can be attached below the apparatus at threaded connection 49 .
As indicated by arrows 28 , as this apparatus is lowered into the casing 16 by the work string 12 solids adhering to the casing wall 14 and fluids below the cup seals are directed into the work string 12 through ports 75 and 76 located in the cup sleeve 73 and mandrel 64 . Fluid is prevented from entering annular space 78 located between mandrel 64 and shifting sleeve 55 by seals 79 . Thus fluid is directed through the work string 12 to the surface where it can flow to the mud or filter system.
After reaching the desired depth, application of surface pressure to the interior of the work string 12 will first shear screws 27 forcing plug 29 out the bottom of the assembly to the bottom of the well or into a plug catcher sub (not shown) located at the end of all devices below the lowermost apparatus in the work string (this apparatus), secondly this pressure will shear screws 77 allowing shifting sleeve 55 to move downward until it contacts bottom sub 74 . As this movement occurs seals 79 are moved below port 76 opening ports 75 and 76 to the annular space 78 between the mandrel 64 and shifting sleeve 55 thereby opening a path through port 80 to the annulus above the upper cup seal 65 . Prior to the shifting sleeve 55 contacting the bottom sub 74 surface 83 of the shifting sleeve will open “C” ring 84 . When shifting sleeve 55 contacts bottom sub 74 “C” ring 84 will snap into grove 82 of shifting sleeve 55 . This “C” ring 84 will hold shifting sleeve in this position. With this arrangement the shifting sleeve once shifted cannot be returned to its original position.
Now referring to FIGS. 8 and 8A , as shown by arrows 81 reverse circulation can now occur by pumping fluid into the annulus between the casing 16 and work string 12 at the surface. This fluid will then be directed through ports 80 , annular spaces 78 and ports 75 and 76 of all such devices in the well to the lower most end of all devices where it will enter the interior of the work string 12 to be directed to the surface and back to the mud or filter system.
The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without departing from the spirit of the invention.
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Several well bore clean-out apparatus' are disclosed that provides a method of cleaning a well bore while the apparatus' are being deployed into a well forcing well bore fluid into a work string and for moving solids to the surface. A method of cleaning multiple diameters of well casings is also disclosed. A method of circulating or reverse circulating the well at anytime during the deployment of the apparatus' is disclosed.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is the U.S. national phase of PCT Application No. PCT/CN2009/070699 filed Mar. 9, 2009, the disclosure of which is incorporated in its entirety by reference herein.
TECHNICAL FIELD
The present invention relates to a communication system, especially to an apparatus and method for compensating for clipping power losses in the communication system.
BACKGROUND OF THE RELATED ARTS
FIG. 1 shows a typical transmit lineup used in a communications system. A baseband signal is generated [ 1 ] which can theoretically be shifted up to a desired carrier frequency and transmitted through the communications medium. However, modern communications systems use amplitude modulation which produces a signal with a large peak to average ratio (PAR). The PAR is also known as the crest factor (CF) of a signal. A signal with a large PAR is difficult to amplify in a real world transmitter because it places stringent requirements on the analog components of the TX path. Specifically, a D/A [ 2 ] needs more dynamic range and a power amplifier (PA) [ 3 ] becomes very inefficient.
Very often, a crest factor reduction (CFR) module [ 4 ] is inserted in the TX lineup. The purpose of the CFR module [ 4 ] (also sometimes called a clipping module) is to reduce the PAR of the signal while introducing as few distortions into the signal as possible. Several different CFR algorithms are in existence, but one factor many have in common is that the gain of the CFR module is not constant. For example, it may be that at low TX power levels, the gain of the CFR module is 0 dB. However, at high TX power levels, the gain of the CFR module may be −0.9 dB.
This presents a problem because it is difficult for the baseband signal generation module [ 1 ] to guarantee the actual signal power level that will be delivered to the communications medium. The actual TX power level may be lower or even higher than what the baseband signal generator assumes it to be. From a system performance perspective, it would be better if there was a method to guarantee that the gain of the TX path remains constant.
One method that is often used to correct for the gain error of the CFR module is to add a gain module [ 15 ] after the CFR module [ 4 ], as can be seen in FIG. 2 . In the gain module [ 15 ], a gain is applied that is equal in value and opposite in sign to the gain going through the CFR module [ 4 ]. Thus, the overall gain of the CFR module [ 4 ] and the gain module [ 15 ] together will be 0 dB.
One of the beneficial features of typical CFR modules is that for a wide range of average input power values, the peak instantaneous value on the output of the CFR module remains more or less constant, or at most changes very slightly. For example, when transmitting at the maximum rated power of the transmitter, the average power on the output of the CFR module may be −13 dB with the peaks located at approximately −5 dB. If the average TX power is reduced to −15 dB, the peaks on the output of a typical CFR module will still be typically located around −5 dB.
The fact that the peak instantaneous power values coming out of the CFR module are constant for a wide range of TX power values is of beneficial to all the components that come after the CFR module. For example, if the peak power values are more or less constant, less headroom is required by the D/A converter [ 2 ] since no margin is needed to cover varying peak power levels.
The problem with the prior art described in FIG. 2 is that because the gain of the gain multiplier [ 15 ] will be changing, the peak values coming out of the gain multiplier will not be consistent and will vary in time. This places more difficult requirements on the D/A converter [ 2 ] and even may place more difficult requirements on a digital predistortion (DPD) system that may be present in the TX lineup.
There is a need for technical solutions for which the peaks of the signal being transmitted is consistent over a wide range of TX power values.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an apparatus for compensating for clipping power losses, which has the benefit that the peaks of the signal to be transmitted will be consistent over a wide range of TX power values. The apparatus comprises: a gain multiplier for applying a gain to a signal input into a crest factor reduction module in a TX chain, so that a power of a signal output from the crest factor reduction module is equal to a power of a signal output from a baseband signal generation module in the TX chain, wherein the gain multiplier is arranged between the baseband signal generation module and the crest factor reduction module.
In accordance with a certain embodiment of the invention, the apparatus further comprises: a device for calculating the gain by using the power of the signal output from the baseband signal generation module and the power of the signal output from the crest factor reduction module, and outputting the calculated gain to the gain multiplier.
In accordance with a further embodiment of the invention, the apparatus further comprises: a first power estimator for estimating the power of the signal output from the baseband signal generation module and outputting the estimated power of the signal output from the baseband signal generation module to the device; and a second power estimator for estimating the power of the signal output from the crest factor reduction module and outputting the estimated power of the signal output from the crest factor reduction module to the device.
In accordance with a further embodiment of the invention, the device performs an iteration algorithm to calculate the gain.
In accordance with a further embodiment of the invention, the iteration algorithm is given by G(n+1)=G(n)+alpha*(P BB (n)−P CFR (n)), wherein P BB is the power of the signal output from the baseband signal generation module, P CFR is the power of the signal output from the crest factor reduction module, G(0) is set to 0 dB, n is a iteration time, and alpha is set according to gain characteristics of the crest factor reduction module.
In accordance with a further embodiment of the invention, the calculated gain is specified to be within but never fall outside of a specified range.
In accordance with a still further embodiment of the invention, the apparatus further comprises: a device for calculating the gain by using the power of the signal output from the baseband signal generation module, and outputting the calculated gain to the gain multiplier, wherein in the TX chain a gain of the crest factor reduction module is a function of a power of the signal input into the crest factor reduction module.
In accordance with a further embodiment of the invention, the apparatus further comprises: a power estimator for estimating the power of the signal output from the baseband signal generation module and outputting the estimated power to the device.
In accordance with a further embodiment of the invention, the device further comprises: a means for receiving the power of the signal output from the baseband signal generation module and outputting the calculated gain corresponding to the power of the signal output from the baseband signal generation module to the gain multiplier by looking up a table, the table being produced by the device to map the power of the signal output from the baseband signal generation module to the calculated gain and stored in the means.
In accordance with a further embodiment of the invention, the function is stored in the device, and the device calculates the gain to be applied to the signal input into the crest factor reduction module, by using the function stored in the device and the power of the signal output from the baseband signal generation module, so that an overall gain of a cascade of the gain multiplier and the crest factor reduction module is 0 dB.
In accordance with a further embodiment of the invention, the device calculates a value of the gain by subtracting a first power which is equal to the power of the signal output from the baseband signal generation module from a second power, the second power is a horizontal coordinate value of an intersection of a line with a slope of −1 dB and a curve of the function, the line with a slope of −1 dB passes through an intersection of a vertical line with a horizontal coordinate value of the power of the signal output from the baseband signal generation module and a horizontal line with a vertical coordinates value of 0 dB.
In accordance with a further embodiment of the invention, when the line with the slope of −1 dB and the curve of the function have multiple intersections, the second power is set to a horizontal coordinate value of one intersection with the horizontal coordinate nearest to the power of the signal output from the baseband signal generation module.
Another object of the present invention is to provide an apparatus for compensating for clipping power losses, which has the benefit that the peaks of the signal to be transmitted will be consistent over a wide range of TX power values. The apparatus comprises: a gain compensation device, the gain compensation device being configured to calculate a gain by using a power of a signal output from a baseband signal generation module in a TX chain and a power of a signal output from a crest factor reduction module in the TX chain, and apply the calculated gain to a signal input into the crest factor reduction module, so that the power of the signal output from the crest factor reduction module is equal to the power of the signal output from the baseband signal generation module.
In accordance with a certain embodiment of the invention, the gain compensation device is configured to perform an iteration algorithm for calculating the gain.
In accordance with a further embodiment of the invention, the iteration algorithm is given by G(n+1)=G(n)+alpha*(P BB (n)−P CFR (n)), wherein P BB is the power of the signal output from the baseband signal generation module, P CFR is the power of the signal output from the crest factor reduction module, G(0) is set to 0 dB, n is a iteration time, and alpha is set according to gain characteristics of the crest factor reduction module.
In accordance with a further embodiment of the invention, the calculated gain is specified to be within but never fall outside of a specified range.
A further object of the present invention is to provide an apparatus for compensating for clipping power losses, which has the benefit that the peaks of the signal to be transmitted will be consistent over a wide range of TX power values. The apparatus comprises: a gain compensation device, the gain compensation device being configured to calculate a gain by using a power of a signal output from a baseband signal generation module in a TX chain, and apply the gain to a signal input into a crest factor reduction module in the TX chain, so that a power of a signal output from the crest factor reduction module is equal to the power of the signal output from the baseband signal generation module, wherein in the TX chain a gain of the crest factor reduction module is a function of a power of the signal input into the crest factor reduction module.
In accordance with a certain embodiment of the invention, the gain compensation device is configured to produce a table to map the powers of the signal output from the baseband signal generation module to the calculated gains, and apply one of the calculated gains corresponding to one of the powers of the signal output from the baseband signal generation module by looking up the table.
In accordance with a further embodiment of the invention, the gain compensation device is configured to calculate a value of the gain by subtract a first power which is equal to the power of the signal output from the baseband signal generation module from a second power, the second power is a horizontal coordinate value of an intersection of a line with a slope of −1 dB and a curve of the function, the line with a slope of −1 dB passes through a intersection of a vertical line with a horizontal coordinate value of the power of the signal output from the baseband signal generation module and a horizontal line with a vertical coordinates value of 0 dB.
In accordance with a further embodiment of the invention, when the line with the slope of −1 dB and the curve of the function have multiple intersections, the second power is set to a horizontal coordinate value of one intersection with the horizontal coordinate nearest to the power of the signal output from the baseband signal generation module.
An another object of the present invention is to provide a method for compensating for clipping power losses, which has the benefit that the peaks of the signal to be transmitted will be consistent over a wide range of TX power values. The method comprises: applying a gain to a signal input into a crest factor reduction module in a TX chain, so that a power of a signal output from the crest factor reduction module is equal to a power of a signal output from a baseband signal generation module in the TX chain.
In accordance with a further embodiment of the invention, the method further comprises: calculating the gain by using the power of the signal output from the baseband signal generation module and the power of the signal output from the crest factor reduction module.
In accordance with a further embodiment of the invention, in the step of calculating, the gain is calculated by performing an iteration algorithm.
In accordance with a further embodiment of the invention, the iteration algorithm is given by G(n+1)=G(n)+alpha*(P BB (n)−P CFR (n)), wherein P BB is the power of the signal output from the baseband signal generation module, P CFR is the power of the signal output from the crest factor reduction module, G(0) is set to 0 dB, n is a iteration time, and alpha is set according to gain characteristics of the crest factor reduction module.
In accordance with a further embodiment of the invention, the calculated gain is specified to be within but never fall outside of a specified range.
In accordance with a further embodiment of the invention, the method further comprises: calculating the gain by using the power of the signal output from the baseband signal generation module, wherein in the TX chain a gain of the crest factor reduction module is a function of a power of the signal input into the crest factor reduction module.
In accordance with a further embodiment of the invention, in the step of calculating, the gain is calculated by using the function and the power of the signal output from the baseband signal generation module, so that an overall gain of the calculated gain adding the gain of the crest factor reduction module is 0 dB.
In accordance with a further embodiment of the invention, the gain is calculated by subtracting a first power which is equal to the power of the signal output from the baseband signal generation module from a second power, the second power is a horizontal coordinate value of a intersection of a line with a slope of −1 dB and a curve of the function, the line with a slope of −1 dB passes through a intersection of a vertical line with a horizontal coordinate value of the power of the signal output from the baseband signal generation module and a horizontal line with a vertical coordinates value of 0 dB.
In accordance with a further embodiment of the invention, when the line with the slope of −1 dB and the curve of the function have multiple intersections, the second power is set to a horizontal coordinate value of one intersection with the horizontal coordinate nearest to the power of the signal output from the baseband signal generation module.
A further object of the present invention is to provide a method for compensating for clipping power losses, which has the benefit that the peaks of the signal to be transmitted will be consistent over a wide range of TX power values. The method comprises: calculating a gain by using a power of a signal output from a baseband signal generation module in a TX chain and a power of a signal output from a crest factor reduction module in the TX chain; and applying the calculated gain to a signal input into the crest factor reduction module, so that the power of the signal output from the crest factor reduction module is equal to the power of the signal output from the baseband signal generation module.
In accordance with a certain embodiment of the invention, in the step of calculating, the gain is calculated by using an iteration algorithm.
In accordance with a further embodiment of the invention, the iteration algorithm is given by G(n+1)=G(n)+alpha*(P BB (n)−P CFR (n)), wherein P BB is the power of the signal output from the baseband signal generation module, P CFR is the power of the signal output from the crest factor reduction module, G(0) is set to 0 dB, n is a iteration time, and alpha is set according to gain characteristics of the crest factor reduction module.
In accordance with a further embodiment of the invention, the calculated gain is specified to be within but never fall outside of a specified range.
A further object of the present invention is to provide a method for compensating for clipping power losses, which has the benefit that the peaks of the signal to be transmitted will be consistent over a wide range of TX power values. The method comprises: calculating a gain by using a power of a signal output from a baseband signal generation module in a TX chain; and applying the calculated gain to a signal input into a crest factor reduction module in the TX chain, so that a power of a signal output from the crest factor reduction module is equal to the power of the signal output from the baseband signal generation module, wherein in the TX chain a gain of the crest factor reduction module is a function of the power of the signal input into the crest factor reduction module.
In accordance with a certain embodiment of the invention, in the step of calculating, the gain is calculated by using the function and the power of the signal output from the baseband signal generation module, so that an overall gain of the calculated gain adding the gain of the crest factor reduction module is 0 dB.
In accordance with a further embodiment of the invention, the gain is calculated by subtracting a first power which is equal to the power of the signal output from the baseband signal generation module from a second power, the second power is a horizontal coordinate value of a intersection of a line with a slope of −1 dB and a curve of the function, the line with a slope of −1 dB passes through a intersection of a vertical line with a horizontal coordinate value of the power of the signal output from the baseband signal generation module and a horizontal line with a vertical coordinates value of 0 dB.
In accordance with a further embodiment of the invention, when the line with the slope of −1 dB and the curve of the function have multiple intersections, the second power is set to a horizontal coordinate value of one intersection with the horizontal coordinate nearest to the power of the signal output from the baseband signal generation module.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a typical communication TX chain which includes a CFR module (Prior Art);
FIG. 2 shows post CFR gain compensation (Prior Art);
FIG. 3 shows a closed loop embodiment of the invention;
FIG. 4 shows an open loop embodiment of the invention;
FIG. 5 shows an example with reference to a CFR gain function f( ) of the invention;
FIG. 6 shows another example with reference to the CFR gain function f( ) of the invention; and
FIG. 7 shows an example with reference to another CFR gain function f( ) of the invention.
DETAILED DESCRIPTION OF THE INVENTION
An embodiment is described with reference to FIG. 3 . In this embodiment, the baseband signal generation module [ 1 ] creates a baseband version of the signal that should be transmitted over the communications medium. The output of this module is sent through the gain multiplier [ 8 ] which applies a gain to the signal so that the power on the output of the subsequent CFR module [ 4 ] will be equal to the power of the signal from the baseband generation module [ 1 ]. The output of the CFR module [ 4 ] is passed to the D/A converter [ 2 ] from which point it is shifted up in frequency using a mixer [ 9 ] and finally sent to the power amplifier [ 3 ].
Two power estimators [ 5 ] and [ 16 ] are used to estimate the power of the signal coming from the baseband generation module [ 1 ] and also the power of the signal coming out of the CFR module [ 4 ] respectively. Several algorithms are generally known that can be used to estimate the power of a signal. In one algorithm, the average of the square of the absolute value of several samples is computed. The number of samples to be averaged varies depending on the desired accuracy of the power estimator. Another algorithm is that the square of the absolute value of the signal may be sent through an alpha filter which performs long term averaging. By adjusting the alpha value of the filter, more averaging can be used to produce more and more accurate estimates of the power of the signal.
The power estimator [ 5 ] on the output of the baseband signal generator [ 1 ] will produce regular power estimates P BB (n) measured in dB. The power estimator [ 16 ] on the output of the CFR module [ 4 ] will produce regular power estimates P CFR (n) measured in dB. The closed loop gain calculator [ 7 ] will examine P BB (n) and P CFR (n) to determine the next gain value G(n+1) that should be used by the pre-CFR multiplier [ 8 ]. The update equation used by the closed loop gain calculator [ 7 ] is given by:
G ( n+ 1)= G ( n )+alpha*( P BB ( n )− P CFR ( n )) Eq 1
Where G(n), P BB , and P CFR are expressed in dB and the initial value for G, ie G(0) is 0 dB. Alpha typically takes on values between 0 and 1 and can be used to trade off convergence against stability. The higher the value of alpha, the more quickly the algorithm will converge. The lower the value of alpha, the more stable the algorithm will be. And it should be noted that in some instances, depending on the gain characteristics of the CFR module, values greater than 1 may be suitable. In an example, alpha will take on a value around 0.8. In another example, if we have a rough idea of what the gain of the CFR will be for different power levels, we could use this information to allow the system to converge more rapidly.
In addition to the update procedure shown by Eq 1, some hard limits may be specified to make sure that the gain never falls outside a specified range. The reason for setting hard limits is that any power estimation module can possibly make power estimation mistakes. If enough mistakes are made, it is possible for the gain value to become very large or very small. One way to prevent this is to declare a maximum and a minimum possible gain value. Thus, even if there are many severe power estimation errors, the gain will stay within a reasonable range. For example, an upper limit and a lower limit may be specified for G(n). If any update produces a G(n) value above the upper limit, G(n) may be forced back to this upper limit. If any update produces a G(n) lower than the lower limit, G(n) may be forced back to this lower limit.
In an ideal situation where there are no power estimation errors, when P BB (n) is equal to P CFR (n), the iterative procedure will finish. Then the gain value G(n) used by the gain multiplier [ 8 ] will not be changed, until the gain of the CFR module [ 4 ] begins to change again. However, in practical situations, because power estimation modules are not perfect, the actual gain value will be constantly changing, even if the TX power is not changing. Thus, P CFR (n) will be constantly changing, but it will retain a value close to P BB (n).
There are many situations, where the gain of the CFR module is not simply a function of the power level on the input to the CFR module. There are situations where the gain is also a function of several other factors, such as, for example, the number of carriers being transmitted or the exact distribution of power among the different carriers. In such situations, the embodiment described in FIG. 3 is preferred because it can adaptively search out and find the optimal gain value that should be applied on the input to the CFR module. Further more, this embodiment is also applicable when the gain of the CFR module is a known and unchanging function of the average power of the signal coming into the CFR module.
Another embodiment of the invention is shown in FIG. 4 . This embodiment is applicable when the gain of the CFR module is a known and unchanging function of the average power of the signal coming into the CFR module. In other words, this embodiment is applicable if the gain of the CFR module can be expressed as:
G CFR =ƒ( P CFR — in ) Eq 2
Where G CFR is the gain of the CFR module, P CFR — in is the average power of the signal coming into the CFR module, and f( ) is any function that is continuous in the range between 0 and the maximum expected value for P CFR — in .
The baseband signal generation module [ 1 ] creates a baseband version of the signal that should be transmitted over the communications medium. The output of this module is sent through a gain multiplier [ 8 ] which applies a gain to the signal so that the power of the signal output from the subsequent CFR module [ 4 ] will be equal to the power of the signal from the baseband signal generation module [ 1 ]. The output of the CFR module is passed to the D/A converter [ 2 ] from which point it is shifted up in frequency using a mixer [ 9 ] and finally sent to the power amplifier [ 3 ].
The output of the baseband signal generator [ 1 ] is also sent to a power estimation module [ 5 ] which attempts to estimate the power of the signal coming from the baseband signal generator [ 1 ]. Several algorithms are generally known that can be used to estimate the power of a signal. In one algorithm, the average of the square of the absolute value of several samples is computed. The number of samples to be averaged varies depending on the desired accuracy of the power estimator. Another algorithm is that the square of the absolute value of the signal may be sent through an alpha filter which performs long term averaging. By adjusting the alpha value of the filter, more averaging can be used to produce more and more accurate estimates of the power of the signal.
The output of the power estimation module [ 5 ] is sent to an open loop gain calculation module [ 6 ] which decides which gain value should be applied to the gain multiplier [ 8 ] so as to ensure that the power of the signal coming out of the CFR module [ 4 ] is equal to the power of the signal coming from the baseband signal generator [ 1 ].
The procedure by which the gain value used by the gain multiplier [ 8 ] is calculated will be described graphically using FIG. 5 . Line [ 10 ] represents a typical CFR gain curve where, in this example, the gain is 0 dB for CFR input power levels below −16 dB. Above −16 dB, the gain of the CFR module [ 4 ] begins to gradually decrease as the input power level is increased more and more. Please note that line [ 10 ] and −16 dB are ‘typical’ for the CFR modules in this example. Different CFR modules will have different curves.
Assume, for the purpose of the example, that the power level coming from the baseband signal generation module [ 1 ] is −13 dB and hence the desired power level on the output of the CFR module [ 4 ] is also −13 dB. Line [ 12 ] represents this baseband power level and it can be seen that if a signal with a −13 dB power level is placed on the input to the CFR module [ 4 ], the gain will be about −0.7 dB and the power of the output of the CFR module [ 4 ] will be about −13.7 dB.
Clearly, the power of the signal on the input to the CFR module [ 4 ] must be increased to compensate for this gain loss. However, it is not sufficient to increase the power of the signal coming into the CFR module [ 4 ] by 0.7 dB to −12.3 dB. A −12.3 dB power level appearing on the input to the CFR module [ 4 ] will cause the CFR module [ 4 ] to have a gain of approximately −0.9 dB, since at this input power level, the gain of the CFR module [ 4 ] decreases as the input power level increases. Thus, the power of the signal coming out of the CFR module [ 4 ] will be −12.3 dB −0.9 dB=−13.2 dB. This is closer to the desired output power of −13 dB, but not exactly correct.
To calculate the correct gain value that must be applied to the input of the CFR module [ 4 ], one must draw a line starting from the intersection of the vertical line [ 12 ] placed at the baseband power level of −13 dB and a horizontal line [ 11 ] at the gain of the CFR module [ 4 ] of 0 dB. This line will have a slope such that there is a −1 dB change in the y direction for every +1 dB change in the x direction and is indicated in FIG. 5 by line [ 13 ].
The intersection between line [ 13 ] and line [ 10 ] represents the desired operating point. In the current example, this intersection is approximately located at (−11.9, −1.1). This means that if the signal input to the CFR module [ 4 ] has a power of −11.9 dB, the gain of the CFR module [ 4 ] will be −1.1 dB and the output of the CFR module [ 4 ] will have a power of −13 dB, as desired. Thus, the gain that should be applied to the input of the CFR module [ 4 ] is represented by the length of line [ 14 ], which is 1.1 dB.
It is noted that the overall gain of the gain multiplier and CFR module is:
OverallGain= G+ ƒ( P BB +G ) Eq 3
Where G, P BB , and f( ) are all expressed in dB. Since it is desired that the overall gain be 0 dB, mathematically, one needs to find the value of G such that:
G=− ƒ( P BB +G ) Eq 4
The length of line [ 14 ] is the solution to the above equation.
Another example is shown in FIG. 6 when the baseband power level is −14 dBFS. In this case, performing the same procedure described above, the gain before the CFR module should be set to +0.5 dB so that the output of the CFR module will have a power level of −14 dBFS.
Another example is shown in FIG. 7 where the baseband power level is again −14 dBFS, however, in this case, the gain of the CFR module is positive and hence G must be set to a negative dB value so that the overall gain of the system will be 0 dB. In this example, the gain before the CFR module should be set to −0.9 dB so that the output of the CFR module will have a power level of −14 dBFS.
It should be noted that it is possible for line [ 13 ] (or line [ 23 ] or line [ 33 ]) and line [ 10 ] (or line 30 ) to intersect several times. In this case, any intersection is a valid solution, but in order to keep the power levels in the system as consistent as possible, it is best to choose the solution whose x coordinate is as close as possible to line [ 12 ] (or line [ 22 ] or line [ 32 ]). It is also possible for line [ 13 ] and line [ 10 ] to never intersect. In this situation, no solution is available, and it is not possible to adjust the gain of the signal coming into the CFR module [ 4 ] so that the cascade of the gain multiplier [ 8 ] and the CFR module [ 4 ] will produce an overall gain of 0 dB.
It should be noted that in this embodiment, the procedure by which the gain value used by the gain multiplier [ 8 ] is calculated is performed in the OL gain calculator, so the CFR gain function is stored in the OL gain calculator.
Although the procedure above was described through the use of graphical methods, the procedure could also easily be implemented using a computer. Furthermore, all the calculations for all the possible baseband power levels could be performed once, offline, that is, the calculations are done once by a computer which will produce a table mapping baseband power estimates to gain values. Then the calculated gain values are stored in the open loop gain calculator [ 6 ], so that the open loop gain calculator [ 6 ] is simply implemented as a lookup table. The currently estimated baseband signal power is used as an index into the lookup table and the value returned from the table is used directly as the gain for the multiplier [ 8 ] before the CFR module [ 4 ].
The invention has two main benefits. One benefit is that the invention will ensure that the gain of the full lineup of the entire TX chain will be constant, regardless of whether the gain of the CFR module is constant or not. Please note that this assumes that the overall gain of all the other modules in the TX chain is also of constant gain. This benefit can also be achieved by the prior art described in FIG. 2 . Furthermore, this invention has the benefit that the peaks of the signal to be transmitted will be consistent over a wide range of TX power values, because the signal to be transmitted directly comes out of the CFR module. This will have a positive impact on the choice of D/A converter and also on any DPD circuit that may appear in the TX lineup. This benefit is the main benefit of the invention and can not be achieved by the prior art described in FIG. 2 .
While several embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes and modifications may be made without departing from the spirit and scope of the invention.
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An apparatus and method for compensating for transmit power losses that are caused by the addition of a clipping or crest factor reduction module in the TX path of a communications system. The method includes applying a gain to a signal input into the crest factor reduction module, so that a power of a signal output from the crest factor reduction module is equal to a power of a signal output from a baseband signal generation module in the TX chain. The apparatus and method have the benefit that the peaks of the signal to be transmitted will be consistent over a wide range of TX power values.
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