description stringlengths 2.98k 3.35M | abstract stringlengths 94 10.6k | cpc int64 0 8 |
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BACKGROUND OF THE INVENTION
The invention relates to a transmission coupling. The invention relates more particularly to a coupling where access is difficult such as in subsea well head operations.
In order to operate, for example, under sea well head control apparatus which is secured to the well head itself, operating means are suspended from cables attached to vessels floating above the well head. In order to operate the under sea well head control apparatus, the operating means must be coupled to the apparatus. As the operating personnel are on the vessel above the well head and the operating means are suspended below the vessel by cables, proper mechanical alignment between the operating means and the well head control apparatus is often difficult, if not impossible to accomplish.
SUMMARY OF THE INVENTION
One of the principal objects of the invention is to provide a reliable mechanical connection for torque transmission. Another object of the invention is to provide a connection between a driven portion and a driving portion of a transmission even when the portions are not aligned. Still another object of the invention is to provide simplicity of connection. And still another object of the invention is to provide guide means to facilitate coupling even when there is considerable misalignment between the portions of the transmission. A still further object of the coupling of the instant invention is to provide constant torque transmission even where the portions of the transmission may be non-aligned.
Further objects and advantages of the invention will be set forth in part in the following specification and in part will be obvious therefrom without being specifically referred to, the same being realized and attained as pointed out in the claims hereof. Other objects of the invention will in part be obvious and will in part appear hereinafter.
With the above and other objects of the invention in view, the invention consist in the novel construction, arrangement and combination of various devices, elements and parts, as set forth in the claims hereof, certain embodiments of the same being illustrated in the accompanying drawings and described in the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and object of the invention, reference should be had to the following detailed description, taken in connection with the accompanying drawings, in which:
FIG. 1 is a fragmentary sectional view of a transmission coupling in accordance with the invention, with the plug and socket non-aligned;
FIG. 2 is a sectional view similar to FIG. 1, but showing a modification, and showing the plug and socket aligned;
FIG. 3 is an end elevational view of the front portion of the plug of FIG. 1; and
FIG. 4, is an elevational view of the socket.
The foregoing and other objects of the invention will be best understood from the following description of exemplification thereof, reference being had to the accompanying drawings wherein:
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In carrying the invention into effect in the embodiments which have been selected for illustration in the accompanying drawings and for description in the specification, and referring now particularly to FIGS. 1-4, a coupling 11, is provided to transmit torque from a first driving portion or connecting means 12 to a second driven portion 13 through an intermediate plug 14 formed with an elongated axis 26.
The connection means may be an Oldham type coupling 112 as shown in FIG. 2; or it may comprise, as shown in FIG. 1, a prismatic cavity 16 having for example a square shape in which there is retained a matching crowned prismatic rear end portion 21 having a crowned surface 34, at the rear portion of the plug 14. A thrust button 29 is provided at the rear of the plug 14 to help prevent binding of the plug 14 while permitting the plug 14 to oscillate. The thrust button 29 bears against a plate 19.
A transmission means such as a crowned prismatic for example, quadratic, outer surface 31 on the front portion 22 of the plug 14, and a matching prismatically shaped cross-section for the inner surface 32 of a socket 17 as provided in the driven portion 13, is provided intermediate the plug 14 and the socket 17 by which torque is transmitted from the plug 14 to the socket 17.
In the preferred embodiment, the front portion 22 of the plug 14 has a frontal taper 28 and a crowned prismatic for example square or quadratic portion 22. The matching prismatically shaped cross-section as shown in the exemplification of FIG. 4 is an eight-pointed star. The star shape is formed by two squares which are displaced for about 45° from one another. The socket 17 terminates in a suitable shaft hub (not shown). The depth "D" of the socket 17 is measured along an elongated central axis 24. The plug 14 has a width "w". The depth "D" of the socket 17 and the width "w" of the plug 14 are such that the deeper the plug penetrates into the socket the closer the axis 26 of the plug 14 and the axis 24 of the socket 17 will be aligned.
As shown in FIG. 2, holes 101 may be provided in the driven portion 113 to communicate interiorly with the socket 17 to permit the outflow of water and debris from the socket 17 when the plug 118 enters the socket 17.
Guide means 27 are provided on the driven portion 13 to facilitate the plug engagement with the socket especially when the longitudinal axes 24, 26 and 33 are non-aligned.
For use in undersea operations, the coupling 11 should be made of a suitable, water resistant material.
OPERATION OF THE INVENTION
The operation of the above described embodiments of the invention is as follows:
In operation of the preferred embodment, the socket 17 is mounted in the driven portion or connecting means 13 to be turned and the plug 14 is mounted on the remotely controlled driving portion 12. The driver (not shown) with the plug 14 connected to it by a connecting means 12 or 112 is brought into position adjacent to the socket 17. The plug 14 is then advanced, in a direction paralled to axis 24, towards the socket 17. The front portion 28 of the plug may contact the guide surfaces 27 of the driven portion 13 and be directed into the socket 17 even though the plug axis 26 and socket axis 24 are not aligned. The crowned prismatic front portion 22 of the plug 14 can interconnect with the socket 17 even though their respective axes 26 and 24 are not completely aligned as shown in FIG. 1. The connecting means 12 or 112 provide two degrees of freedom normal to the axis 33 of the driving means 12 thus further axial movement of the driving means 12 causes the plug 14 to be cammed towards the matching socket 17, at the same time the prismatic surface 31 of the plug 14 seeks to match the face on the socket 17 rotating the plug 14 into alignment with the socket 17 (see FIGS. 3 and 4). Should the square on the plug 14 be balanced on a corner, the plug 14 will then interconnect in the square portion of the socket 17 cross-section (FIG. 4) which is offset from the prismatic surfaces 31 by 45°.
When the plug 14 is engaged with the star-shaped socket (FIG. 4), power is applied to the plug 14 through the connection means 12 or 112. The Oldham coupling 112 accommodates an offset between the axis 26 of the plug 14 and the axis 133 of the driving portion 112; while the crowned prismatic front portion 22 of the plug 14 accommodates an angular misalignment with the socket. For the embodiment of the connecting means 12 shown in FIG. 1, a crowned square 21 at the rear portion of the plug 14 which is provided with a spherical thrust button 29 and is retained in a square socket 16, is a spherical surface which bears against a plate 19 in the bottom of the square socket 16 to allow the plug 14 to oscillate without binding.
I wish it to be understood that I do not desire to be limited to exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art. | A coupling for use in self-engaging and subsequently aligning two portions of a transmission for remote coupling of the portions even when the portions are not aligned. | 5 |
FIELD OF INVENTION
The present invention relates to modular assemblies and is particularly concerned with electronic equipment comprising a supporting structure and a plurality of circuit sub-assemblies or modules mounted to the supporting structure wherein the modules require periodic removal from and replacement into the supporting structure.
BACKGROUND OF THE INVENTION
In conventional rack-mounted computer systems, a number of substantially planar electronics modules are arranged in horizontal or vertical planes extending from a front face of the rack to a rear face thereof. The modules are all connected to a vertical back plane by means of connectors arranged on a back edge of each module mating with co-operating connectors on the backplane. Installation and removal of individual modules from the system is effected by moving the modules in a horizontal direction towards or away from the backplane to connect or disconnect the connectors. The modules are received in horizontally-extending guides to ensure correct alignment and support for the modules.
The components of the electronics modules generate heat when they operate, and in order to remove this heat cooling air is caused to flow over the electronic components of the modules, with air being drawn in at one side of the module and expelled at the opposite side. The cooling air flows are preferably arranged to be in the same direction for all of the modules of the system, so that heated air expelled from one module is not drawn into a neighbouring module. Since a typical installation of a rack-mounted system will comprise a plurality of racks situated side-by-side, the direction of the cooling airflow is usually arranged to be from the “front” of the system to the “back”. The vertical backplane, however, presents a barrier to such a cooling airflow and necessitates a change in airflow direction, which reduces cooling efficiency.
An improved front-to-back airflow is achieved by arranging the modules in vertical planes extending from front to back relative to the supporting structure in the rack-mounted system, with the interconnection of the modules being made by a horizontally arranged “baseplane” rather than a vertically arranged backplane. The front to back cooling airflow thus runs parallel to the plane of the baseplane, and heated air can be expelled from the back of each module without having to change direction to exit the system.
Mounting the baseplane in a horizontal orientation however requires the insertion and removal of modules from the system to be effected by moving the module vertically rather than horizontally to connect it to and disconnect it from the baseplane. For the modules to be insertable and removable with a single linear movement relative to the system supporting structure, the modules may be guided in vertical guides relative to the supporting structure, but to prevent the module from falling during insertion or removal an operative must support the weight of the module during insertion and removal procedures. The modules may weigh several kilograms, typically from 5 to 15 kg, and may have to be lifted or lowered at arm's length.
The modules and their exposed connectors are easily damaged if dropped, and the baseplane of the system may also be damaged if a module is dropped during insertion and falls on to the baseplane.
The present invention seeks to provide a motion control device and a modular assembly for housing a computer system which comprises the motion control device, and modules for an assembly, for controlling the movement of detachable modules relative to the supporting structure of the modular assembly.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, there is provided an assembly for housing a modular electronic circuit, the assembly comprising a supporting structure having vertically extending guides, and at least one circuit module engageable with the guides for movement in a vertical direction between a mounted position and a dismounted position, the circuit assembly further comprising a motion control device having a first component provided on the module and a second component provided on the supporting structure, the first and second components of the motion control device being cooperable to resist downward movement of the module in the guides relative to the supporting structure.
According to a second aspect of the invention, there is provided a motion control device for providing a first degree of resistance to relative movement between first and second objects in a first movement direction, and a second, a smaller, degree of resistance to relative movement between the objects in a second movement direction opposite to the first.
A third aspect of the invention provides a motion control device for a modular assembly comprising a supporting structure and at least one module movable relative to the supporting structure in a movement direction into and out of a mounted position, the motion control device comprising an elongate engagement surface provided on either the supporting structure or module to extend in said movement direction, a rotatable element mountable to the other of the supporting structure and the electronic module to engage the engagement surface for rolling movement therealong, and a retarding device operable to resist rotation of the rotatable element in at least one rotation direction.
A fourth aspect of the invention provides a component for a motion control device, the component comprising a mounting plate, a swinging arm pivotally attached at one of its ends to the mounting plate for swinging movement towards and away from the mounting plate, a rotatable element mounted to a second end of the swinging arm, and a friction clutch or brake operable between the swinging arm and the rotatable element to resist rotation of the rotatable element in at least one rotation direction.
The invention provides, in further aspects, an electronic circuit module comprising a component of a motion control device, and a supporting structure for a modular circuit comprising a component of a motion control device.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described in detail with reference to the accompanying drawings, in which like parts are given like reference numbers. In the drawings:
FIG. 1 is a perspective view of a modular computer system with vertically-arranged modules;
FIG. 2 is a schematic front view of a first motion control device according to the invention;
FIG. 3 is a side view of the motion control device of FIG. 2 ;
FIG. 4A is a side view showing a module, module guides, and the motion control device;
FIG. 4B is a detail perspective view of the upper end of the left-hand guide of FIG. 4A ;
FIG. 4C a sectional view taken in the plane X—X of FIG. 4B ;
FIG. 5 is a schematic perspective view of a second motion control device of the present invention;
FIG. 6 is a schematic perspective view of a third motion control device of the present invention;
FIG. 7 is a schematic perspective view of a fourth motion control device of the present invention;
FIG. 8 is a schematic perspective view showing alternative engagements between the motion control device of the present invention and an electronics module; and
FIGS. 9A , 9 B and 9 C are side, front, and perspective views, respectively, of a fifth motion control device according to the invention; and
FIG. 10 is a schematic perspective view of a sixth motion control device according to the invention.
DETAILED DESCRIPTION
Referring now to the Figures, FIG. 1 shows a perspective view of modular assembly comprising a plurality of substantially planar electronic modules mounted in vertical orientations in slide-out drawers of a rack chassis to form a computing circuit.
In the embodiment shown, the chassis 1 comprises three drawers 2 , each drawer housing a number of electronic modules 3 .
The modules 3 are generally planar in configuration, and are arranged in vertical planes in the drawers 2 .
The drawers 2 are slidingly mounted to the chassis 1 for movement in the direction of arrow A between a retracted, operating position and an extended, maintenance position. The lowermost drawer 2 is shown in the extended, maintenance position, while the upper two drawers are in the operating position.
In the embodiment illustrated, the modules 3 are mounted in vertical planes within the drawers, vertical guides 4 being provided to receive opposing edges of the modules 3 in sliding engagement. In the lowermost drawer 2 of the chassis 1 shown in FIG. 1 , the modules 3 are arranged in planes extending across the drawer, i.e. perpendicularly to the movement direction (A) of the drawer. It is, however, also possible that the modules may be arranged in planes extending from the front to the back of the drawer, as illustrated in relation to the uppermost drawer in FIG. 1 .
To provide cooling airflow over the components of the electronic modules, cooling fans 5 may be provided on the chassis 1 or on the drawer 2 . When the modules are arranged to extend across the drawer, as in the lowermost drawer in FIG. 1 , then cooling fans 5 may be mounted on the side of the chassis 1 . An array of fans may be provided on each side of the chassis, one array drawing air from the outside and blowing it between the modules 3 within the drawer 2 , and the other array of fans extracting air from within the drawer and exhausting it to the outside.
When the modules are mounted front-to-back in the drawer, as in the uppermost drawer in FIG. 1 , the cooling fans 5 may be mounted to the drawer front 6 , and/or either to a back wall of the drawer or to a back wall of the chassis 1 to provide a horizontal air flow between the modules 3 within the drawer 2 . In this arrangement, the modules 3 are mounted in front-to-back orientation within the drawer, and cooling air is drawn in through the drawer front 6 and expelled through the rear of the chassis 1 .
Electrical connections between the modules 3 are made through a horizontal base plane 7 situated in the bottom of each drawer 2 , the base planes 7 of the drawers 2 being optionally connected to each other by cabling. The electronic modules 3 are electrically connected to the base planes by means of connectors situated on the lower edges of the modules 3 which cooperate with connecting sockets 8 on the base planes.
The electronic modules 3 are supported within the drawers 2 by means of vertically-extending guides 4 into which opposite edges of the electronic module 3 engage. In order to insert or remove a module 3 , the module is moved vertically in the guides 4 towards or away from the base plane 7 . In order to prevent the module 3 from freely falling in the guides 4 if the operative should release his grip on the module during insertion or removal, a motion control device is provided between the module 3 and the drawer 2 . A first embodiment of the motion control device is shown schematically in FIGS. 2 and 3 .
FIG. 2 is a front view and FIG. 3 is a side view of a motion control device and a module, showing only the operative parts of the assembly. The motion control device comprises a toothed wheel 10 mounted to a swinging arm 11 which is pivotally attached to a support 2 a of the drawer 2 , and a toothed rack 12 fixed to the module 3 and engageable with the toothed wheel 10 as the module moves along the guides 4 .
The module 3 comprises a main circuit board 3 a (“motherboard”) to which subsidiary circuit boards 3 b (“daughterboards”) are attached by means of connectors 3 c . The main circuit board 3 a has a pair of opposing vertical side edges 3 d which are engageable with the vertical guides 4 mounted to the drawer 2 . The lower edge 3 e of the main circuit board is provided with protruding connector portions 3 f which are engageable with connection sockets 8 disposed on the base plane 7 .
The upper edge of the main circuit board 3 a is attached to a handle assembly 9 which provides a handling grip 9 a and latching levers 9 b , which will be described later.
The toothed rack 12 is attached to the main circuit board 3 a to extend parallel to the side edge 3 d . The rack 12 has its toothed face in a plane perpendicular to the plane of the main circuit board 3 a , facing towards the side edge 3 d.
The swinging arm 11 of the motion control device is pivotally mounted to a support 2 a of the drawer 2 by means of a pivot pin 13 . A biassing spring 14 extends between attachment points 15 and 16 on a support 2 b of the drawer 2 and the swinging arm 11 , respectively, to apply a tensile force causing the swinging arm 11 to rotate anti-clockwise as shown in FIG. 3 . This biassing force urges the free end of the swinging arm 11 towards the toothed face of the rack 12 . A limit stop 17 is provided on the drawer 2 , to limit the clockwise rotation of the swinging arm 11 .
At the free end of the swinging arm 11 , the toothed wheel 10 is mounted for rotation about an axle 18 . In the embodiment shown, the swinging arm 11 is in the form of a clevis, having a pair of slide plates 11 a between which the toothed wheel 10 is mounted. The axle 18 extends through aligned bores in the side plates 11 a.
To apply a frictional force resisting the rotation of the toothed wheel 10 , a friction disk 19 is interposed between the toothed wheel 10 and one of the side plates 11 a of the swinging arm 11 . A compression spring 20 bears at one end on an adjusting nut 21 attached to the axle 18 , and bears at its other end against the side plate 11 a of the swinging arm 11 . The compression spring 20 applies a tensile force to the axle 18 , which draws the toothed wheel 10 and friction disk 19 into close contact with the inside face of the side plate 11 a . The urging together of the side plate, friction disk and toothed wheel provides a friction force on the toothed wheel which resists relative rotation of the toothed wheel and the swinging arm. The magnitude of the frictional resistance can be adjusted by adjusting the compression in the compression spring 20 , by moving the adjusting nut 21 along the axle 18 .
With the module 3 removed from the drawer 2 , the biassing spring 14 urges the swinging arm 11 to rotate until the swinging arm 11 contacts the limit stop 17 . As a module is inserted into the drawer 2 , by engaging the side edges 3 d of the main circuit board of the module 3 with the vertical guide channels 4 , the lower end of the toothed rack 12 will contact the toothed wheel 10 . The lower end of the toothed rack 12 may have an oblique lead-in surface 22 . As the toothed wheel 10 engages the lead-in surface 22 , downward movement of the module 3 will cause the swinging arm 11 to rotate in a clockwise direction as seen in FIG. 3 , tensioning the biassing spring 14 . Further downward movement of the module 3 will cause the teeth of the toothed wheel 10 to engage with the teeth of the rack 12 , so that the toothed wheel 10 will thereafter be rotated by continued downward movement of the module 3 . This rotation of the toothed wheel 10 is resisted by the friction disk 19 , and thus provides a retarding force against movement of the module 3 .
Preferably, the amount of compression in the compression spring 20 is adjusted so that the frictional resistance to rotation of the toothed wheel 10 is not overcome unless the module 3 is subjected to a downward force applied by an operative. In other words, the frictional resistance of the toothed wheel 10 is capable of supporting the self-weight of the module 3 when the module is at rest, and is also capable of arresting downward movement of the module when an externally-applied downward force is removed.
In order that the toothed wheel 10 is retained in close engagement with the rack 12 , the flank angles of the teeth of the toothed wheel 10 and the rack 12 are so arranged that the reaction force acting on the toothed wheel 10 during insertion of the module 3 results in a moment about the pivot pin 13 which urges the swinging arm 11 to rotate anti-clockwise, bringing the toothed wheel 10 into closer engagement with the rack 12 .
As the operative applies a downward force to the module 3 , frictional resistance of the toothed wheel 10 is overcome and the module moves down the guides 4 . The length of the rack 12 is so arranged that resistance to downward movement is provided until the electrical contacts 3 f at the lower edge of the main circuit board 3 a are engaged with the connection socket 8 of the base plane 7 .
The final movement of the module 3 to connect the module with the connection socket is preferably achieved by means of the latching levers 9 b of the handle assembly 9 of the module 3 . Latching levers 9 b are moved to a raised position (shown in broken lines in FIG. 3 ) for removal and insertion of the module, and are rotated to a lowered position (shown in solid lines in FIG. 3 ) to lock the module into the drawer. With the latching lever in its raised position, the module 3 is moved into the guides 4 until the connecting portion 3 f is adjacent the connection socket 8 of the base plane 7 . The latching lever 9 b is then rotated (anti-clockwise as seen in FIG. 3 ) so that a detent 9 b 1 of the lever 9 b engages with an abutment surface 22 of the drawer 2 . As the latching lever 9 b is rotated to its closed position, a lever action urges the module 3 downwards so that the connection portion 3 f enters the connecting socket 8 to complete the installation of the module.
In order to remove the module from the drawer, the latching levers 9 b are raised to disengage the detent 9 b 1 from the abutment surface 22 .
The detent 9 b 1 may engage an upward-facing abutment (not shown) so that raising the latching levers 9 b also raises the module 3 to disengage the electrical connection portion 3 f from the connecting socket 8 . The handle 9 a is then grasped and a vertical upward force applied to the module. As the module moves upwardly, the friction disk 19 provides a resistance to rotation of the toothed wheel 10 . However, the reaction force between the rack 12 and the toothed wheel 10 is now acting to rotate the swinging arm 11 in the clockwise sense as seen in FIG. 3 , tending to disengage the toothed wheel 10 from the rack 12 . The toothed wheel 10 preferably does not rotate, but “jumps” over the teeth of the rack 12 , providing a ratchet-type engagement. Should the operative cease to apply the vertically upward force withdrawing the module 3 , the module is prevented from falling back in the guides by the engagement of the toothed wheel 10 and the rack 12 . As the direction of the reaction force changes, the toothed wheel 10 is brought into close engagement with the rack 12 to prevent downward movement of the module.
In FIGS. 1 to 3 , the module 3 is provided with a single rack 12 extending vertically adjacent one of its side edges 3 d . Since the centre of gravity of the module 3 is spaced horizontally from the rack 12 , the reaction between the toothed wheel 10 and the rack 12 causes a moment to be applied to the module, tending to rotate it about a horizontal axis perpendicular to the plane of the module. This rotation can cause the edges 3 d of the module to become jammed in the guides 4 . FIG. 4 shows an arrangement for overcoming this difficulty by providing a pair of reaction rollers to counteract the moment caused by the asymmetric vertical forces.
FIG. 4A illustrates schematically a module 3 having a rack 12 , and a pair of vertical guides 4 . The right-hand guide is separated into upper and lower portions, between which is mounted a swinging arm 11 and toothed wheel 10 biassed towards the rack 12 by a biassing spring 14 . Adjacent the lower edge 3 e of the module, at its side adjacent the rack 12 , a first reaction roller 23 is mounted to the main circuit board 3 a of the module 3 . In the embodiment shown, the first reaction roller 23 engages an inwardly-facing surface of the guide 4 , to produce a horizontal reaction on the module 3 indicated by the arrow R 1 in FIG. 4A . At the upper end of the left-hand guide, a second reaction roller 24 is provided to engage the edge 3 d of the main circuit board 3 a . The reaction between the second reaction roller 24 and the module 3 produces a second horizontal reaction force on the module 3 , indicated by the arrow R 2 .
As the module 3 is moved downwardly between the guides 4 , the reaction forces R 1 and R 2 provide a moment to counteract the moment generated by the horizontal offset of the reaction force on the rack 12 and the downward force on the module 3 . The module 3 is thus prevented from rotating and jamming in the guides 4 .
As an alternative to the reaction rollers 23 and 24 , the module may be provided with a symmetrical arrangement of two racks 12 , to cooperate with respective toothed wheels 10 mounted on swinging arms 11 adjacent each of the guides 4 . Such an arrangement will provide a symmetrical force distribution, and prevent jamming of the main circuit board 3 a in the guide 4 . It will be appreciated that if the centre of gravity of the module 3 is offset relative to the vertical centre line of the module, this will generate a moment tending to jam the module in the guides if the reaction forces exerted by both of the toothed wheels are equal. It is therefore foreseen that the reaction forces of the two toothed wheels may be different from each other, in order to compensate for horizontal offsetting of the centre of gravity of the module. To achieve this, the compression spring 20 of the motion control device nearest to the centre of gravity of the module is adjusted to increase the frictional resistance of its toothed wheel 10 , so as to provide a larger reaction force at the side edge nearest the centre of gravity of the module.
FIG. 5 shows an alternative arrangement for the motion control device. In the arrangement shown in FIG. 5 , the rack 12 of the module 3 is engaged by an idler wheel 25 , which meshes with a toothed wheel 10 mounted on a support 2 c of the drawer 2 for rotation about an axis fixed in relation to the drawer 2 . Link arms 26 connect the centres of the toothed wheel 10 and the idler wheel 25 , and a biassing spring 14 coupled to a support 2 d of the drawer 2 urges the link arms to rotate in order to bring the idler wheel 25 into close engagement with the rack 12 . A friction resistance device operates on the toothed wheel 10 to resist rotation of the toothed wheel 10 in both directions, and this resistance is transmitted to the rack 12 during insertion of the module. As described previously, the flank angles of the teeth of the idler wheel 25 and the toothed rack 12 are so arranged that reaction forces on the idler wheel 25 urge the idler wheel 25 into closer engagement with the rack 12 during insertion of the module, and cause the idler wheel 25 to “jump” over the teeth in the rack 12 when the module is removed.
As before, the motion control device may be provided at one side only of the drawer, and the module may be provided with a first reaction roller 23 as before, with a second reaction roller 24 being provided in the guide opposite the motion control device. Alternatively, two motion control devices may be provided, as described above.
A further alternative embodiment of the motion control device is illustrate in FIG. 6 . In this arrangement, the toothed rack 12 is positioned on the module 3 with the toothed face of the rack oriented to face away from the plane of the module 3 .
The toothed wheel 10 is mounted to axle 18 , and rotation of the axle 18 relative to the swinging arm 11 is resisted in one direction only by a unidirectional clutch. In the embodiment shown, a “Spragg” clutch is used, wherein a coil spring 27 is wrapped around the axle 18 , and a tangentially-extending free end 28 of the coil spring 27 is captured between abutments 29 on the swinging arm 11 . The direction of wrapping of the coil spring 27 round the axle 18 is such that rotation of the toothed wheel 10 caused by insertion of the module 3 is resisted, due to the frictional engagement between the spring 27 and the axle 18 tending to wrap the spring 27 more tightly about the axle 18 . Conversely, as the module 3 is removed from the drawer 2 , rotation of the toothed wheel 10 is in the sense which causes friction between the spring 27 and the axle 18 to loosen the coils of the spring 27 , thus reducing resistance to rotation of the toothed wheel 10 . The module is therefore removable from the drawer with substantially no resistance being applied by the engagement of the toothed wheel 10 and the rack 12 . The coiled spring 27 shown in FIG. 6 may be replaced by any other suitable unidirectional friction element.
It will be appreciated that, with the toothed surface of the rack 12 facing away from the main circuit board 3 a , the reaction between the toothed wheel 10 and the rack 12 will produce a reaction force on the module which is perpendicular to the plane of the module 3 , increasing frictional resistance to movement between the edges of the main circuit board 3 a and the guides 4 . To counteract this, a second motion control device and a second rack 12 may be provided on the rear face of the module 3 , aligned with the rack 12 on the front face so that the reaction forces produced by the respective motion control devices will cancel each other out. Alternatively, a supporting bearing may be provided on the near face of the module.
FIG. 7 shows a further alternative arrangement of the motion control device. The arrangement is similar to that shown in FIG. 5 , with the toothed wheel 10 being mounted to the drawer 2 with friction means to resist rotation of the toothed wheel 10 . An idler wheel 25 is provided, with the axle 30 of the idler wheel 25 received in a slot 31 in a guide 32 mounted to the drawer 2 . The slot 31 may be straight, as shown in FIG. 7 , or may be arcuate and concentric with the axis of the toothed wheel 10 . The slot 31 is arranged so as to be downwardly convergent towards the rack 12 , so that the reactions on the idler wheel 25 as the module 3 is inserted into the drawer cause the idler wheel 25 to be drawn into close engagement with the rack 12 and with the toothed wheel 10 . When the module 3 is lifted out of the drawer 2 , the idler wheel 25 is moved upward in the slot 31 and engagement between the idler wheel 25 and the rack 12 is released, allowing the module 3 to be removed substantially without resistance, as the idler wheel 25 “jumps” across the teeth of the rack 12 . Should the module start to reenter the drawer, the idler wheel 25 is immediately engaged with the teeth of the rack 12 to prevent the module 3 from falling.
FIG. 8 illustrates schematically alternative methods of engaging the motion control device and the module, otherwise by than the rack-and-pinion arrangements shown in FIGS. 1 to 7 .
At the upper part of FIG. 8 , there is shown a friction engagement wherein a friction surface 33 adjacent the edge 3 d of the main circuit board 3 a is engaged by a friction roller 34 . The friction roller 34 may be supported on a shaft 35 so as to resist relative rotation of the roller 34 and shaft 35 in both directions by means of a friction clutch. Alternatively, the roller 34 may be mounted to the shaft 35 to resist relative rotation only in the insertion direction of the module 3 . In order to provide sufficient pressure between the friction roller 34 and the friction surface 33 , a back up roller 36 may be provided behind the module 3 . In the arrangement shown, the back up roller 36 is mounted on a shaft 37 , and the shafts 35 and 37 are mounted adjacent the free ends of a pair of swinging arms 38 a and 38 b pivotally mounted to a support 2 e of the drawer 2 . A tension spring 39 urges the ends of the arms 38 together, so that the friction roller 34 and the back up roller 36 form a nip through which the edge region of the main circuit board 3 a passes during insertion and removal of the module.
The lower part of FIG. 8 shows a further alternative arrangement, wherein a series of recesses or openings 40 formed in an edge region of the main circuit board 3 a are engaged by projections 41 on a sprocket roller 42 . The sprocket roller 42 may be controlled by a unidirectional or bidirectional friction clutch, either directly or via a transmission, and may be urged into engagement with the main circuit board by being mounted on a swinging arm as illustrated in relation to the friction roller 34 .
The recesses or openings 40 may be circular, as shown in FIG. 8 , or may be square or rectangular. The recesses or openings may have edges shaped to cooperate with a gear wheel, or sprocket wheel.
FIG. 9 illustrates a motion control device for attachment to a drawer of chassis to provide motion control for a vertically movable module 3 . The motion control element comprises a fixing plate 45 providing with fixing locations 46 and 47 to accept fasteners such as screws, bolts of the like. Upstanding edges 48 of the fixing plate 45 support a pivot pin 49 on which is supported a gear housing 50 . A biassing spring 51 is mounted between the fixing plate 45 and the gear housing 50 , to urge the gear housing 50 away from the base plate 45 . A heel part 52 of the gear housing 50 is contactable with the fixing plate 45 to limit the movement of the gear housing 50 away from the fixing plate.
The gear housing 50 supports a gear shaft 53 on which is mounted a gear wheel 54 . Within the gear housing 50 is contained a friction clutch which provides frictional resistance to rotation of the gear wheel 54 in the clockwise sense as seen in FIG. 9A .
In use, the motion control device of FIG. 9 is attached to the drawer 2 , so that the gear housing 50 is supported in such a position as to engage the rack 12 of a module 3 insertable in guides in the drawer. The motion control device may be provided only at one side of a module, adjacent one of the guides. Alternatively, two motion control devices may be provided for each module, one mounted adjacent each of the guides. The racks 12 and motion control devices may be arranged with the axis of the gear wheel 54 extending either parallel to or perpendicular to the plane of the main circuit board 3 a of the module. The friction device within the gear housing 50 may provide frictional resistance to rotation of the gear wheel 54 in both rotation directions, or only in one.
A further embodiment of the invention is illustrated in FIG. 10 , again with like parts being given like reference numerals.
In this embodiment, the motion control device is mounted to the main circuit board 3 a of the module, and engages a rack fixed to the supporting chassis or drawer. In this embodiment, the vertical guide which receives the edge of the main circuit board is formed with a toothed rack surface. In FIG. 10 , the main circuit board 3 a of the module 3 is provided with a mounting pin 55 on which is pivotally mounted a swinging arm arrangement 56 to support a toothed wheel 57 . A tension spring 58 is fixed to the swinging arm 56 and to an anchor pin 59 , to apply a moment to the swinging arm 56 to urge the toothed wheel 57 towards the edge 3 d of the main circuit board 3 a . The swinging arm 56 is arranged to extend downwardly and outwardly relative to the main circuit board 3 a (when the main circuit board is in its insertion position). The guide 4 is provided with a rack surface 60 engageable by the toothed wheel 57 . It will be understood that the rack surface 60 may be provided as a separate component to the guide 4 .
During insertion of the module 3 into the drawer 2 , the toothed wheel 57 engages the rack surface 60 and a friction device resisting rotation of the toothed wheel 57 provides an upward reaction force on the mounting pin 55 to support the weight of the module 3 . When the operative exerts a downward pressure on the module 3 , the toothed wheel 57 is rotated in engagement with the rack surface 60 and the module is moved into the drawer 2 . When an operative applies an upward force to the module 3 , the toothed wheel 57 may “jump” over the teeth of the rack surface 60 , if, the rotation of the toothed wheel 57 is resisted in both directions. If a unidirectional clutch is provided, then the toothed wheel 57 may remain in engagement with the rack surface 60 but provide no resistance to removal of the module.
It will be understood that any of the motion control devices described above may be mounted to the module 3 rather than to the drawer 2 , with the rack 12 mounted to the drawer 2 for engagement with the motion control device.
An advantage to mounting the motion control device on the module is that the frictional resistance provided by the motion control device may be tailored to suit the particular module to which it is mounted, with different degrees of frictional resistance being provided for modules of different mass. Each module may be provided with a single motion control device, or they may be mounted symmetrically in pairs. When a single motion control device is provided, the module and its guide may also be provided with reaction rollers. However, if the motion control device is mounted adjacent the lower edge of the main circuit board 3 a , then the horizontal reaction produced by the motion control device may be sufficient to prevent jamming of the module in the guides.
While in the embodiments shown the electronic modules 3 are moved downwards to their installed positions, it is possible that the modules 3 may be mounted in “overhead” positions in which the modules are moved vertically upwardly during insertion to their mounted positions, and are removed by withdrawing them vertically downwards. Such a situation may arise in avionic applications where systems must be accommodated in limited space. It will be appreciated that the motion control devices are usable in such “overhead” mounting systems, but the direction of the resistance force applied to the module will be such as to prevent the module from falling out of its mount, rather than to prevent the module from falling into its mounted position.
It is also contemplated that the motion control devices may be provided to control insertion and/or removal of modules mounted for horizontal insertion and removal, to prevent an accidental application of excessive force resulting in the module being moved too quickly into or from its mounted position.
The movement speed of the module may be controlled in any of the above-described embodiments or situations by providing a resistance force which increases as the speed of the module relative to the supporting assembly increases, for example by using centrifugal clutch or a fluid damper device in addition to, or instead of, the friction clutch. | There is described a motion control device for preventing free-fall of electronics modules during vertical movement into or out of a supporting structure. The system comprises a rotatable element on the module or structure engageable with surface on the structure or module, respectively, for rolling movement therealong. The rotatable element is provided with a clutch or brake to provide resistance to rotation at least when the module is moving downward relative to the structure. The rotatable element may be a gear engageable with a toothed rack, or a friction roller engageable with a friction surface. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation-in-part of U.S. Non-Provisional application Ser. No. 12/371,727 filed Feb. 16, 2009, and is a continuation-in-part of U.S. patent application Ser. No. 11/427,796 filed Jun. 30, 2006, both of which are hereby incorporated in their entirety herein.
FIELD
[0002] The invention relates to flow restriction devices and, more particularly, to flow restriction devices having a degradable portion.
BACKGROUND
[0003] Materials that react to external stimuli, for instances changes to their surrounding environments, have been the subject of significant research in view of the potential they offer to sectors of the economy as diverse as the medical, consumer-market, transportation, chemical and petro-chemical sectors. For example, such an advanced material that would have the remarkable ability to degrade in order to actuate a well-defined function as a response to a change in its surrounding may be desirable because no or limited external human intervention would be necessary to actuate the function. Such a material, essentially self-actuated by changes in its surrounding (e.g., the presence or ingress of a specific fluid, or a change in temperature or pressure, among other possible changes) may potentially replace costly and complicated designs and may be most advantageous in situations where accessibility is limited or even considered to be impossible.
[0004] In a variety of subterranean and wellbore environments, such as hydrocarbon exploration and production, water production, carbon sequestration, or geothermal power generation, equipment of all sorts (e.g., subsurface valves, flow controllers, zone-isolation packers, plugs, sliding sleeves, accessories, etc) may be deployed for a multitude of applications, in particular to control or regulate the displacement of subterranean gases and liquids between subsurface zones. Some of these equipments are commonly characterized by relatively complex mechanical designs that are controlled remotely from the rig at ground level via wirelines, hydraulic control lines, or coil tubings.
[0005] Alternatively it may be desirable and economically advantageous to have controls that do not rely on lengthy and costly wirelines, hydraulic control lines, or coil tubings. Furthermore, in countless situations, a subterranean piece of equipment may need to be actuated only once, after which it may no longer present any usefulness, and may even become disadvantageous when for instance the equipment must be retrieved by risky and costly interventions. In such situations, the control or actuation mechanisms may be more conveniently imbedded within the equipment. In other applications, it may be beneficial to utilize the inherent ability of a material for reacting in the presence of an environmental change; for instance such a material may be applied to chemically sense the presence of formation water in a hydrocarbon well. In other foreseen applications, such a degradable material, if complemented by high mechanical strengths, may present new advantages in aquatic environments not only to withstand elevated differential pressures but also to control equipments deployed underwater with no or limited intervention.
[0006] In some instances, by way of example only, in the petroleum industry, it may be desirable to deploy a piece of equipment, apparatus, or device that performs a pre-determined function under differential pressures and then degrades such that the device no longer requires retrieval or removal by some method. By way of example only it may be advantageous to perform a multiple-stage oilfield operation such as that disclosed in U.S. Pat. No. 6,725,929. However, after the so-called ball, dart or plug is released in the wellbore to block gas and liquid transfers between isolated zones, it may be desirable to remove it by milling, flow-back, or alternate methods of intervention. In some instances, it may be simply more advantageous to manufacture equipments or devices, such as, by way of example only, balls, darts or plugs using a material that is mechanically strong (hard) and degrades under specific conditions, such as in the presence of water-containing fluids like fresh water, seawater, formation water, brines, acids and bases.
[0007] Unfortunately, the degradability of metallic materials, as defined by their lack of stability in a defined environment, as well as their ability to rapidly degrade (as opposed to the slow and uniform rusting or weight loss corrosion of steels for instance) may, in some instances, be accompanied with a number of undesirable characteristics. For example, among the very few metals that react and eventually fully degrade in water, both sodium metal and lithium metal, in addition to having low mechanical strengths, are water-reactive to the point they present great hazard along with great manufacturing, procurement, shipping and, handling challenges. Calcium metal is another reactive metal that in spite of being lesser reactive and slower to reacts than either sodium or lithium does not possess enough mechanical strength for normal engineering applications. Like sodium metal and lithium metal, calcium metal is thus unfit to many of the pressure-holding applications found for instances in the chemical and petroleum industries. When deficient, the properties of metals may be enhanced by alloying, meaning the chemical mixing of two or more metals and some other substances to form an end product, or alloy, with new properties that may be suitable for practical use. However, the alloying of lithium, sodium, or calcium metals with other metals and substances is not without major metallurgical and manufacturing challenges, and therefore the likelihood of creating an alloy with attractive engineering combinations of high strength, high toughness, and the proper degradability and rate of degradation (in a specific condition) is not only doubtful but also difficult to economically justify.
[0008] Table 1 compares several properties of pure metals with that of exploratory alloys in their annealed conditions (i.e., in the absence of cold working). Are listed in Table 1 measurements of hardness (Vickers hardness, as defined in the ASTM E370 standard) and galvanic corrosion potential, as simply established from voltage average readings of dissimilar metals and alloys electrically coupled by a aqueous electrolyte (here a sodium chloride enriched water). In this document, hardness and microhardness are considered to be fully interchangeable words; i.e., no distinction is made between the two words. Vickers hardness, or Vickers Microhardness, is a well-accepted and straight-forward measure that may be monotonically correlated to the mechanical strength of metals or alloys; e.g., the greater the hardness, the higher the mechanical strength of the material. Differently, galvanic corrosion potential is an electro-chemical measure of reactivity, more precisely degradability, in an aqueous electrolytic environment, as produced by the coupling of materials with unlike chemical potentials. Though a low galvanic corrosion potential correlates to high degradability in water-containing fluid and often to high rates of degradation, rates of degradation are also influenced by other factors (e.g., water chemistry, temperature, pressure, and anode-to-cathode surface areas). Therefore, simplistically correlating rate of degradation to corrosion potential, despite being macroscopically correct as shown in Table 1, is not fully accurate for materials exhibiting especially comparable corrosion potentials. With these materials, factors such as temperature and water chemistry often have greater impacts on the rates of degradation than the galvanic corrosion potential itself. Galvanic corrosion potential and degradability may be considered purely as thermodynamic quantities, whereas rate of degradation is a kinetic quantity that is also influenced by other factors.
[0000]
TABLE 1
Vickers
Galvanic
hardness
corrosion
number
potential
(HVN)
(Volts)*
Aluminum metal (99.99 wt. %)
33.3
−0.60
Magnesium metal (99.99 wt. %)
32.5
−0.90
Calcium metal (99.99 wt. %)
23.1
−1.12
80Al—10Ga—10In **
33.4
−1.48
80Al—5Ga—5Zn—5Bi—5Sn **
33.7
−1.28
75Al—5Ga—5Zn—5Bi—5Sn—5Mg **
40.0
−1.38
65Al—10Ga—10Zn—5Bi—5Sn—5Mg **
39.2
−1.28
*Galvanic corrosion potential was measured against a pure copper electrode (99.99 wt. %) in a 5 percent by eight sodium chloride aqueous solution; i.e., 5 wt. % NaCl in water.
** All alloy compositions are listed in weight percent (wt. %); e.g. 80 wt. % Al—10 wt. % Ga—10 wt. % In.
[0009] Of all aluminum alloys, those referred as the “heat-treatable” alloys exhibit some of the most useful combinations of mechanical strength (hardness), impact toughness, and manufacturability; i.e., the ability to readily make useful articles of manufactures. These alloys are also characterized as being precipitation or age-hardenable because they are hardened or strengthened (the two words are interchangeable) by heat treatments that typically consist of three consecutive steps: (1) a solutionizing (solution annealing) heat-treatment for the dissolution of solid phases in a solid α-aluminum (a refers to pure aluminum's phase), (2) a quenching or rapid cooling for the development of a supersaturated α-aluminum phase at a given low temperature (e.g., ambient), and (3) an ageing heat treatment for the precipitation either at room temperature (natural aging) or elevated temperature (artificial aging or precipitation heat treatment) of solute atoms within intra-granular phases. During ageing, the solute atoms that were put into solid solution in the α-aluminum phase at the solutionizing temperature and then trapped by the quench are allowed to diffuse and form atomic clusters within the □-aluminum phase. These clusters or ultra fine intra-granular phases result in a highly effective and macroscopic strengthening (hardening) that provides some of the best combinations of mechanical strength and impact toughness.
[0010] An important attribute of age-hardenable alloys is a temperature-dependent equilibrium solid solubility characterized by increasing alloying element solubility with increasing temperature (up to a temperature above which melting starts). The general requirement for age hardenability of supersaturated solid solutions involves the formation of finely dispersed precipitates during ageing heat treatment. The ageing must be accomplished not only below the so-called equilibrium solvus temperature, but below a metastable miscibility gap often referred as the Guinier-Preston (GP) zone solvus line. For the development of optimal mechanical properties, age-hardening alloys must therefore be heat-treated according to predetermined temperature vs. time cycles. Failures in following an appropriate heat-treatment cycle may result in only limited strengthening (hardening); however any strengthening (hardening) would still be evidence of an ageing response. The presence of age-hardening novel aluminum alloys that possess the unusual ability to degrade in water-containing fluids is a large part of the alloys disclosed herein.
BRIEF DESCRIPTION OF THE FIGURES
[0011] FIG. 1 is a perspective view of a flapper valve;
[0012] FIG. 2 is a side elevational cross sectional view of a ball valve; and
[0013] FIG. 3 is a side elevational view of a tubular within a wellbore.
DETAILED DESCRIPTION
[0014] All alloys shown in Table 2 (including commercially available 6061 alloy) were prepared by induction melting. The alloys were either prepared from commercial alloys, within which alloying elements were introduced from pure metals, or from pure metals. The commercial alloys and the alloying elements were all melted, magnetically, and mechanically stirred in a single refractory crucible. All melts were subsequently poured into 3-in diameter cylindrical stainless steel moulds, resulting in solid ingots weighting approximately 300 grams. The alloy ingots were cross-sections, metallographically examined (results not shown herein), and hardness tested either directly after casting (i.e., in their as-cast condition after the ingots had reached ambient temperature) and/or after ageing heat treatments. The induction furnace was consistently maintained at temperatures below 700° C. (1290° F.) to ensure a rapid melting of all alloying elements but also minimize evaporation losses of volatiles metals such as magnesium. Gaseous argon protection was provided in order to minimize the oxidation of the alloying elements at elevated temperatures and maintain a consistency in the appearance of the cast ingots. All ingots were solidified and cooled at ambient temperature in their stainless steel moulds.
[0015] Solutionizing (solution annealing) was subsequently conducted at 454° C. (850° F.) for 3 hours to create a supersaturated solution. For purposes of simplifications, all alloys were solutionized at this single temperature, even though in reality each alloy has its own and optimal solutionizing (solution annealing) temperature; i.e., each alloy has a unique temperature where solubility of the alloying elements is maximized, and this temperature is normally the preferred solutionizing temperature. Optimal solutionizing (solution annealing) temperatures are not disclosed in this document, as they remain proprietary.
[0016] Immediately after solutionizing (solution annealing), the alloys were oil quenched (fast cooled) to retain their supersaturated state at ambient temperature, and then aged at 170° C. (340° F.) in order to destabilize the supersaturated state and force the formation of a new and harder microstructure with fine precipitates dispersed within an E-aluminum matrix phase. Grain boundary-phase were also observed, but their consequences on alloy properties are not discussed herein, since not relevant to the invention. Vickers microhardness measurements, carried out with 500 g load in accordance with the ASTM E370 standard, were measured at various stages of the ageing heat-treatment all across ingot cross-sections. Though herein are only reported the arithmetic averages of the hardness readings, at least ten microhardness measurements were conducted at each stage of the ageing heat treatment. Hardness was monitored over time for as long as several weeks with the intention to fully replicate the ageing of an alloy in a warm subterranean environment. Hardness vs. time curves were generated to quantify and compare the age-hardening response of the different alloys, as well as the stability of the formed precipitates. FIGS. 1 and 2 compares hardness vs. time responses of 6061 and HT alloy 20, a novel alloy disclosed in Table 2. Despite an evident scatter in the data plotted on FIGS. 1-2 that is characteristic of microstructural imperfections, the novel alloy of FIG. 2 is considerably harder (stronger), exhibiting an average and maximum hardness of about 120 compared to approximately 80 for the cast 6061 alloy in peak-aged condition. Like other well-known age-hardenable alloys, when heat-treated too long at temperatures or over-aged, the novel alloys then experience softening, in stark contrast to the hardening observed earlier during ageing. Rapid decrease in hardness during over-ageing is a direct indication that the formed precipitates are not thermally stable. In stark contrast, stable precipitates, as revealed by no or barely detectable hardness decay over time, may be preferred for most subterranean applications.
[0017] As a substitute to hardness vs. time curves (similar to that of FIGS. 1-2 ), important hardness results are instead summarized in Table 2 for all 26 novel alloys. Also included in Table 2 are their nominal chemical compositions. For comparison purpose, a 6061 alloy (i.e., a non-degradable and commercially-available aluminum alloy), remelted in the same conditions are the novel alloys is also included in Table 2. Reported in Table 2 are the as-cast hardness (a measure of the hardness after casting and with no subsequent heat-treatment of any sorts) and the peak hardness (i.e., the maximum hardness observed during ageing heat treatment). An increase in hardness from as-cast to aged (heat-treated) conditions is an undeniable proof of age-hardenability.
[0018] In Table 2 the alloys are not categorized in the order they were formulated and thus shaped into ingots; instead they are ranked according to their magnesium content (in percent) to specifically demonstrate the contribution of magnesium as an alloying element. In Table 2, alloying element contents, expressed in percent by weight (wt. %) are as follows: 0.5 to 8.0 wt. % magnesium (Mg), 0.5 to 8.0 wt. % gallium (Ga), 0 to 2.5 wt. % indium (Ga), 0 to 2.3 wt. % silicon (Si), and 0 to 4.3 wt. % zinc (Zn).
[0019] All alloys were purposely formulated to demonstrate a wide range of magnesium and gallium, along with other alloying elements found in several series of commercial aluminum alloys, among others. FIG. 3 , which depicts hardness results from all 26 alloys of Table 2, further reveals that all the novel alloys responded to age-hardening; i.e., they may be strengthened by heat-treatments as are commercial alloys such as the 6061 alloy. While magnesium is known to be an effective solid-solution hardening element that is essential to several commercial alloys, gallium is equally well-known for creating grain-boundary embrittlement by liquation; in other words gallium is known to lower mechanical strength (hardness), specifically by promoting a low-temperature creep-type deformation behavior. In fact in the prior art, gallium—like many low-melting point metals (mercury, tin, lead)—is considered to be detrimental to aluminum; thus gallium like other low-melting point elements is only present in commercial aluminum alloys in impurity levels; removal of these elements even in trace quantities has traditionally been chief in achieving high-quality aluminum alloys for industrial use. FIGS. 4 to 8 confirm that magnesium is also a key contributor in raising hardness in the inventive alloys, either in as-cast or aged condition (heat-treated condition). However, magnesium alone does not suffice to generate an elevated age hardening, unless magnesium is properly combined with gallium, as shown in FIGS. 5 and 8 . The data show that hardness values well in excess to that of commercially-available 6061 may be achieved with appropriate combinations of magnesium and gallium (a peak hardness of 140 HVN, well in excess of the measured value in the 80s for the 6061 alloy is reported herein). Not only a maximum hardening occurs at intermediate gallium percentage, as shown in FIG. 5 , the ratio of magnesium-to-gallium is also demonstrated to be important. A ratio of in the vicinity of 2 is shown to result in maximum hardness; for practical purposes, magnesium-to-gallium ratios between 0.5 and 3.5 may be recommended to create a variety of mechanical strengths and rates of degradation.
[0020] Furthermore, as pointed out by FIG. 6 , silicon (an element essential to alloy 6061 to cause age-hardening) is not seen to influence hardness measurably in any of the novel alloys. Unlike magnesium, zinc ( FIG. 7 ) only appears to slightly reduce hardness, an indication that the addition of zinc in the alloys of this invention interferes with the ageing heat-treatment and the magnesium-gallium alloying. The role of zinc in the novel alloys is thus quite different to that seen in typical commercial aluminum alloys. In many commercial aluminum alloys, zinc is utilized to produce high strength with suitable resistance against corrosion and stress-corrosion cracking.
[0000]
TABLE 2
Mg
Ga
In
Si
Zn
As-cast
HT to
(wt. %)
(wt. %)
(wt. %)
(wt. %)
(wt. %)
Mg/Ga
HVN
Peak HVN
6061-
1.0
0.0
0.0
0.6
0.1
—
55
78
alloy
HT alloy 0
0.5
0.5
0.5
0.0
0.0
1.00
42
78
HT alloy 1
0.5
1.0
1.0
0.0
0.0
0.50
42
78
HT alloy 2
2.0
1.0
1.0
0.0
0.0
2.00
50
90
HT alloy 3
2.1
6.5
2.5
1.1
4.2
0.32
49
75
HT alloy 4
2.2
8.0
2.1
1.1
0.1
0.33
50
85
HT alloy 5
2.2
4.7
0.0
1.1
4.4
0.46
67
97
HT alloy 6
2.2
4.4
1.4
1.1
2.2
0.50
51
88
HT alloy 7
2.2
4.7
1.5
1.1
0.1
0.48
51
89
HT alloy 8
2.3
4.9
0.0
0.5
0.1
0.46
55
104
HT alloy 9
2.3
3.4
1.3
2.3
0.1
0.66
52
100
HT alloy 10
2.3
4.8
0.0
1.4
0.1
0.48
66
100
HT alloy 11
2.3
5.1
0.0
0.6
0.1
0.45
63
107
HT alloy 12
2.3
3.5
1.3
0.6
0.1
0.65
51
96
HT alloy 13
2.3
2.4
0.0
0.6
0.1
0.99
57
94
HT alloy 14
2.4
2.4
0.0
1.2
0.1
0.99
58
91
HT alloy 15
2.4
2.3
0.0
0.6
0.1
1.01
62
100
HT alloy 16
3.5
1.0
1.0
0.0
0.0
3.50
60
99
HT alloy 17
4.3
4.4
0.0
0.5
4.3
0.98
91
125
HT alloy 18
4.4
4.4
1.4
1.1
0.1
1.00
66
104
HT alloy 19
4.4
4.7
0.0
2.2
0.1
0.94
69
108
HT alloy 20
4.5
4.5
0.0
1.1
0.1
1.00
75
123
HT alloy 21
4.5
3.4
1.2
0.5
0.1
1.32
69
125
HT alloy 22
6.2
4.1
1.5
1.2
4.1
1.50
86
111
HT alloy 23
6.6
3.3
1.2
0.5
0.1
1.97
75
143
HT alloy 24
8.0
3.8
1.6
1.2
0.0
2.10
88
132
HT alloy 25
8.0
3.8
1.6
0.0
0.0
2.11
85
136
* HT stands for heat-treatable. HVN stands for Hardness Vickers Number; here measured under a 500 g indentation load.
[0021] Galvanic corrosion potentials of several of the 26 alloys of Table 2 are summarized in Table 3. Galvanic corrosion potential is a valuable indicator of the degradability of the alloy in water-containing environments. Galvanic corrosion potential is here measured by connecting to a voltmeter two electrodes immersed in an electrically conductive 5 wt. % sodium chloride aqueous solution. One electrode is made of one of the test alloys, and the other of a reference material, here selected to be some commercially pure copper (e.g., 99.99% Cu). The voltage, directly read on the voltmeter was determined to be the galvanic corrosion potential. Most generally novel alloys characterized by galvanic corrosion potentials lesser than about −1.2 were observed to exhibit high degradabilities; i.e., they react with the surrounding fluid and produced a characteristic gaseous bubbling. For comparison purposes, galvanic corrosion potentials of magnesium and calcium are shown in Table 1 under the same exact test conditions. Some novel alloys were found to be calcium-like by being highly and rapidly degradable at ambient temperature, while others were found to only rapidly degrade in a calcium-like manner at elevated temperatures and despite the fact that their galvanic corrosion potential is lower than that of either magnesium or calcium. For those alloys not listed in Table 3 but included in Table 2, the measured corrosion potentials were between −1.25 and −1.45. Generally, the lowest potentials were for those alloys containing indium. It is clear from Table 3 that gallium and indium are both responsible for the degradability of the novel alloys while other elements tend to either enhance or reduce degradability and rates of degradation. With the alloys of this invention, the contribution of gallium is two-fold: gallium increases both hardness (strength) and degradability.
[0000]
TABLE 3
As-cast (V)
HT to Peak (V)
Cast 6061
−0.60
−0.60
HT alloy 4
−1.47
−1.42
HT alloy 5
−1.30
−1.31
HT alloy 7
−1.42
−1.41
HT alloy 8
−1.30
−1.30
HT alloy 10
−1.28
−1.35
HT alloy 11 †
−1.32
−1.29
HT alloy 13
−1.28
−1.27
HT alloy 14
−1.28
−1.32
HT alloy 15
−1.30
−1.32
HT alloy 19
−1.29
−1.36
HT alloy 20*
−1.31
−1.32
† Galvanic corrosion potential was found to increase slightly as bubbling proceeded.
*Galvanic corrosion potential was unstable, thus making the measurement unreliable.
[0022] Another type of material useful in forming oilfield elements comprises a combination of normally insoluble metal or alloys with metallurgically-soluble (partially/wholly) and/or blendable elements selected from other metals or alloys, semi-metallic elements, and/or non-metallic elements; thus new compositions to form new complex alloys and composite structures of poor stability in the designated fluid environment. Examples of metals preferentially selected to develop high strength include iron, titanium, copper, combinations of these, and the like, among other metals. Second metals, semi-metallic elements, and non-metallic elements contemplated are any metal, semi-metallic element, or non-metallic element that will form a non-durable (degradable) composition with the first element. Examples include metals such as gallium, indium, tin, antimony, combinations of these, and the like; semi-metallic elements such as carboxylated carbon (e.g. in graphitic or nanotube form), and organic compounds such as sulfonated polystyrene, styrene sulfonic acid, and compositions comprising non-metallic materials such as oxides (anhydride), carbonates, sulfides, chlorides, bromides, acid-producing or basic producing polymers, or in general fluid pH changing polymers. Many of these non-metallic materials may contain metals that are chemically-bonded to non-metallic elements (wherein the bonds may be ionic, covalent, or any degree thereof). These materials include, but are not limited to, alkaline and alkaline-earth oxides, sulfides, chlorides, bromides, and the like. These materials, alone, are at least partially water-soluble and, when properly combined (e.g. blended) with normally insoluble metals and alloys, will degrade the chemical resistance of the normally insoluble metals by changing the designated fluid chemistry, including its corrosiveness, thus creating galvanic cells, among other possible mechanisms of degradations. Examples of normally insoluble metals and alloys made soluble through the additions of elements, including polymers, that would directly destabilize the metallic state of the normally insoluble element for a soluble ionic state (e.g. galvanic corrosion, lower pH created by acid-polymers), or indirectly by promoting ionic compounds such as hydroxides, known to predictably dissolve in the designated fluid environment. Also contemplated are exothermic reactions occurring in fluid such as water that may act as trigger to the degradation of one of the composition. The ratio of normally insoluble metal to metallurgically soluble or blendable elements is dependent on the end use of the oilfield element, the pressure, temperature, and element lifetime requirements as well as the fluid environment compositions, and, without limiting the applications, may range from 4:1 to 1:1 for instance.
[0023] Another group of materials useful in oilfield elements includes one or more solubility-modified high strength and/or high-toughness polymeric materials that may be selected from polyamides (including but not limited to aromatic polyamides), polyethers, and liquid crystal polymers. As used herein, the term “polyamide” denotes a macromolecule containing a plurality of amide groups, i.e., groups of the formula —NH—C(═O)— and/or —C(═O)—NH—. Polyamides as a class of polymer are well known in the chemical arts, and are commonly prepared via a condensation polymerization process whereby diamines are reacted with dicarboxylic acid (diacids). Copolymers of polyamides and polyethers may also be used, and may be prepared by reacting diamines with diacids.
[0024] Useful aromatic polyamides include those generically known as aramids. Aramids are highly aromatic polyamides characterized by their flame retardant properties and high strength. They have been used in protective clothing, dust-filter bags, tire cord, and bullet-resistant structures. They may be derived from reaction of aromatic diamines, such as para- and/or meta-phenylenediamine, and a second monomer, such as terephthaloyl chloride.
[0025] Polyethers as a class of polymer are also well known, where one type of polyether is commonly prepared by reaction of an alkylene oxide (e.g., ethylene oxide) with an initiating group (e.g., methanol). The term “polyether” as used herein denotes a macromolecule containing a plurality of ether groups, i.e., groups of the formula R—O—R where R represents an organic (carbon-containing) group. At present, many polyethers are commercially available that have terminating groups selected from amine, hydroxyl and carboxylic acid. Polyethers having two amine terminating groups may be used according to U.S. Pat. No. 6,956,099, incorporated herein by reference, to introduce polyether blocks into a polyamide copolymer. This approach provides blocks of polyether groups within a polyamide copolymer.
[0026] As noted in U.S. Pat. No. 5,057,600, incorporated herein by reference, “poly(etheretherketone)” or “PEEK” refers to a polymeric material which comprises poly(etheretherketone), i.e., [poly(oxy-p-phenyleneoxy-p-phenylenecarbonyl-p-phenylene]. PEEK is a widely available semi-crystalline or amorphous high performance thermoplastic polymeric material. PEEK is soluble in only a few solvents. Some of the solvents require high temperatures while other solvents such as sulfuric acid, sulfonate the PEEK molecules, which alters the polymer and complicates characterization. Solution properties of PEEK have been studied by Berk, C. and Berry, G. C., J. Polym. Sci.: Part B: Polym. Phys., 28, 1873 (1990); Bishop et al., Macromolecules, 18, 86 (1985); Roovers et al., Macromolecules, 26, 3826 (1993); and Roovers, et al., Macromolecules, 23, 1611 (1990).
[0027] Other similar polymeric (PEEK-type polymers) materials such as poly(aryletherketone) (PAEK), poly(etherketone) (PEK), or poly(etherketoneketone) (PEKK), may also be polymers. Further, poly(etheretheretherketone) (PEEEK), poly(etheretherketoneetherketone) (PEEKEK), poly(etheretherketoneketone) (PEEKK), poly etherketoneetherketoneketone) (PEKEKK) are also to be considered as PEEK-type polymers, both individually and as mixtures and as copolymers with each other. Polymer mixtures of these PEEK-type polymers with poly(phenylene sulfide) or “PPS” are also.
[0028] Other degradable materials include those described in U.S. patent application Ser. No. 11/162,184 filed Aug. 31, 2005, and U.S. patent application Ser. No. 11/427,233, filed Jun. 28, 2006, all of which are incorporated by reference in their entirety herein.
[0029] Although the alloys and other materials disclosed and claimed herein are not limited in utility to oilfield applications (but instead may find utility in many applications in which hardness (strength) and degradability in a water-containing environment are desired), it is envisioned that the alloys and other materials disclosed and claimed herein will have utility in the manufacture of oilfield devices. For example, the manufacture of plugs, valves, sleeves, sensors, temporary protective elements, chemical-release devices, encapsulations, and even proppants. Additionally, oilfield devices include, but is not limited to one or more items or assemblies selected from tubing, blow out preventers, sucker rods, O-rings, T-rings, jointed pipe, electric submersible pumps, packers, centralizers, hangers, plugs, plug catchers, check valves, universal valves, spotting valves, differential valves, circulation valves, equalizing valves, safety valves, fluid flow control valves, connectors, disconnect tools, downhole filters, motorheads, retrieval and fishing tools, bottom hole assemblies, seal assemblies, snap latch assemblies, anchor latch assemblies, shear-type anchor latch assemblies, no-go locators, and the like. These oilfield devices can be used in a number of well operations, including fracturing and stimulation operations.
[0030] Well operations include, but are not limited to, well stimulation operations, such as hydraulic fracturing, acidizing, acid fracturing, fracture acidizing, or any other well treatment, whether or not performed to restore or enhance the productivity of a well. Stimulation treatments fall into two main groups, hydraulic fracturing treatments and matrix treatments. Fracturing treatments are performed above the fracture pressure of the reservoir formation and create a highly conductive flow path between the reservoir and the wellbore. Matrix treatments are performed below the reservoir fracture pressure and generally are designed to restore the natural permeability of the reservoir following damage to the near-wellbore area.
[0031] Hydraulic fracturing, in the context of well workover and intervention operations, is a stimulation treatment routinely performed on oil and gas wells in low-permeability reservoirs. Specially engineered fluids are pumped at high pressure and rate into the reservoir interval to be treated, causing a vertical fracture to open. The wings of the fracture extend away from the wellbore in opposing directions according to the natural stresses within the formation. Proppant, such as grains of sand of a particular size, is mixed with the treatment fluid keep the fracture open when the treatment is complete. Hydraulic fracturing creates high-conductivity communication with a large area of formation and bypasses any damage that may exist in the near-wellbore area.
[0032] In the context of well testing, hydraulic fracturing means the process of pumping into a closed wellbore with powerful hydraulic pumps to create enough downhole pressure to crack or fracture the formation. This allows injection of proppant into the formation, thereby creating a plane of high-permeability sand through which fluids can flow. The proppant remains in place once the hydraulic pressure is removed and therefore props open the fracture and enhances flow into the wellbore.
[0033] Acidizing means the pumping of acid into the wellbore to remove near-well formation damage and other damaging substances. This procedure commonly enhances production by increasing the effective well radius. When performed at pressures above the pressure required to fracture the formation, the procedure is often referred to as acid fracturing. Fracture acidizing is a procedure for production enhancement, in which acid, usually hydrochloric (HCl), is injected into a carbonate formation at a pressure above the formation-fracturing pressure. Flowing acid tends to etch the fracture faces in a non-uniform pattern, forming conductive channels that remain open without a propping agent after the fracture closes. The length of the etched fracture limits the effectiveness of an acid-fracture treatment. The fracture length depends on acid leakoff and acid spending. If acid fluid-loss characteristics are poor, excessive leakoff will terminate fracture extension. Similarly, if the acid spends too rapidly, the etched portion of the fracture will be too short. The major problem in fracture acidizing is the development of wormholes in the fracture face; these wormholes increase the reactive surface area and cause excessive leakoff and rapid spending of the acid. To some extent, this problem can be overcome by using inert fluid-loss additives to bridge wormholes or by using viscosified acids. Fracture acidizing is also called acid fracturing or acid-fracture treatment.
[0034] A “wellbore” may be any type of well, including, but not limited to, a producing well, a non-producing well, an injection well, a fluid disposal well, an experimental well, an exploratory well, and the like. Wellbores may be vertical, horizontal, deviated some angle between vertical and horizontal, and combinations thereof, for example a vertical well with a non-vertical component.
[0035] In addition, it may be desirable to use more than one material as disclosed herein in an apparatus. It may also be desirable in some instances to coat the apparatus comprising the degradable material with a material which will delay the contact between the water-containing atmosphere and the degradable material. For example, a plug, dart or ball for subterranean use may be coated with thin plastic layers or degradable polymers to ensure that it does not begin to degrade immediately upon introduction to the water-containing environment. As used herein, the term degrade means any instance in which the integrity of the material is compromised and it fails to serve its purpose. For example, degrading includes, but is not necessarily limited to, dissolving, partial or complete dissolution, or breaking apart into multiple pieces.
[0036] FIGS. 1 and 2 are exemplary valves with which the degradable material may be utilized. As shown in FIG. 1 , a ball valve mechanism 5 can include a body 10 , a seat portion 15 and a ball portion 20 . The ball valve mechanism 5 can be secured by a securing mechanism 25 , such as a bolt, or the ball valve mechanism 5 can be held in place by an external support, such as a shelf or lip on the inner surface of a tubular member. Any or all of the ball valve mechanism 5 can be constructed from a degradable material, including but not limited to the body 10 , seat portion 15 , ball portion 20 and the securing mechanism 25 , so long that as a result of the degradation, a flow path is opened past the location at which the valve 5 was positioned.
[0037] Similar to FIG. 1 , the flapper valve 30 detailed in FIG. 2 can include a valve body 35 , a flapper portion 40 and a hinge connection mechanism 45 between the valve body 35 and flapper portion 40 . Similar to the ball valve mechanism 5 , the flapper valve 30 can be secured by a securing mechanism, such as a bolt, or the flapper valve mechanism 30 can be held in place by an external support 50 , such as a shelf or lip on the inner surface of a tubular member. Any or all of the flapper valve mechanism 30 can be constructed from a degradable material, including but not limited to the body 35 , flapper portion 40 and the external support 50 , a flow path is opened past the location at which the valve 30 was positioned.
[0038] FIG. 3 illustrates a tubular string 55 positioned within a wellbore 60 . A series of packers 65 are positioned within the annulus about the outer surface 70 of the tubular string 55 and include a metal frame portion 75 and a sealing portion 80 which engages the wall 85 of the wellbore 60 . The metal frame portion 75 of the packers 65 can be formed of a degradable material so that, as the frame portion 75 degrades, the packer 65 comes free from the tubular string 55 and can drop down the wellbore 60 . Alternatively, a securing mechanism 90 , such as a bolt, connecting the packer 65 to the outer surface 70 of the tubular string 55 can be formed of a degradable material so that, as the securing mechanism 90 degrades, the packer 65 is no longer secured to the tubular string 55 . Other oilfield elements known to be positionable within the annulus, such as a slip, can further be constructed to include a degradable material so that, upon degradation of the material, a flow path is formed therepast or the oilfield element can drop away from the tubular to a position downhole.
[0039] Within the tubular string 55 are a series of seat members 95 . The seat members 95 include an upwardly facing concave portion 100 to receive a dropped element 105 , such as a ball, therein to provide a fluid barrier. As shown, the seat members 95 can further include a downwardly, facing concave portion 110 which can also be configured to provide a fluid barrier. As shown in FIG. 3 , the seat members 95 can be secured to the tubular string 55 by a securing mechanism 115 , such as a bolt. Alternatively, for example, the seat members 95 can be placed on a ledge 120 extending from an inner surface 125 of the tubular string 55 . The dropped element 105 can be formed of a degradable material so that, as the dropped element 105 degrades, the flow path through the seat member 95 is reopened. Additionally, the seat member 95 can be completely or partially formed of a degradable material, the securing mechanism 115 can be formed of a degradable material, and/or the ledge 120 extending from the inner surface 125 of the tubular string 55 can be formed of a degradable material.
[0040] In addition to the oilfield elements described above, it is contemplated that valves, plugs, balls, seats and other oilfield elements made of a degradable material can be situated to block flow toward the surface until degradation occurs. In particular, these oilfield elements can be configured to block flow from a formation to a position uphole.
[0041] Certain embodiments and features have been described using a set of numerical upper limits and a set of numerical lower limits. It should be appreciated that ranges from any lower limit to any upper limit are contemplated unless otherwise indicated. Certain lower limits, upper limits and ranges appear in one or more claims below. All numerical values are “about” or “approximately” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.
[0042] Various terms have been defined above. To the extent a term used in a claim is not defined above, it should be given the broadest definition persons in the pertinent art have given that term as reflected in at least one printed publication or issued patent. Furthermore, all patents, test procedures, and other documents cited in this application are fully incorporated by reference to the extent such disclosure is not inconsistent with this application and for all jurisdictions in which such incorporation is permitted.
[0043] 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. | A valve device for restricting flow is provided that includes a degradable portion. A method of temporarily blocking flow is also provided which includes a degradable portion of an oilfield element. | 4 |
FIELD
[0001] Embodiments of the present invention relate generally to the field of Raman spectroscopy, nanoparticle reporters, and the detection of cross-functionality between antibodies and antigens.
BACKGROUND
[0002] Antibodies are naturally-occurring proteinaceous molecules that are a component of the innate and adaptive immune system of vertebrates. In vivo, antibodies defend an organism against infection by binding to viruses and microbial toxins, thereby inactivating them. The binding of antibodies to invading pathogens recruits various types of white blood cells and a system of blood proteins to attack the infectious invaders. In vivo, antibodies are produced in billions of forms. Naturally-occurring antibodies typically have two recognition sites, called antigen binding sites that specifically recognize and bind to an antigenic site on a target invader. A given molecule may present more than one different antigenic site.
[0003] Antibodies have found applications as diagnostic agents and therapeutic treatments in humans (such as for auto-immune diseases). Additionally, antibodies have been employed as research tools, such as, for the study of cellular function and the isolation of biomolecules, through for example, immunoprecipitation, immunoblots, immunoassays, cell surface staining. The process of generating and or engineering specific antibodies for specific applications requires tremendous effort. Traditionally the production of an antibody, such as a monoclonal antibody, requires the isolation of an immunogen, immunization of an animal, screening for the antibody of interest, purification, and commercialization which can take years, for example.
[0004] The ability to detect and identify trace quantities of analytes has become increasingly important in many scientific disciplines, ranging from part per billion analyses of pollutants in sub-surface water to analysis of treatment drugs and metabolites in blood serum. Among the many analytical techniques that can be used for chemical analyses, surface-enhanced Raman spectroscopy (SERS) has proven to be a sensitive method. A Raman spectrum, similar to an infrared spectrum, consists of a wavelength distribution of bands corresponding to molecular vibrations specific to the sample being analyzed (the analyte). Raman spectroscopy probes vibrational modes of a molecule and the resulting spectrum, similar to an infrared spectrum, is fingerprint-like in nature. As compared to the fluorescent spectrum of a molecule which normally has a single peak exhibiting a half peak width of tens of nanometers to hundreds of nanometers, a Raman spectrum has multiple structure-related peaks with half peak widths as small as a few nanometers.
[0005] To obtain a Raman spectrum, typically a beam from a light source, such as a laser, is focused on the sample generating inelastically scattered radiation which is optically collected and directed into a wavelength-dispersive spectrometer. Although Raman scattering is a relatively low probability event, SERS can be used to enhance signal intensity in the resulting vibrational spectrum. Enhancement techniques make it possible to obtain a 10 6 to 10 14 fold Raman signal enhancement.
BRIEF DESCRIPTION OF THE FIGURES
[0006] FIG. 1 provides a flow chart outlining a method for determining the degenerate binding ability of antibodies.
[0007] FIG. 2 provides a diagram of a method for determining the degenerate binding ability of antibodies.
[0008] FIG. 3 is a Surface Enhanced Raman Spectroscopy (SERS) spectrum of degenerate binding assays.
[0009] FIG. 4 is a SERS spectrum of a negative control without antibodies.
DETAILED DESCRIPTION OF THE INVENTION
[0010] As used herein, the term antibody is used in its broadest sense to include polyclonal and monoclonal antibodies, as well as antigen binding fragments of such antibodies. An antibody useful in a method of the invention, or an antigen binding fragment thereof, is characterized, for example, by having specific binding activity for an epitope of an analyte. The antibody, for example, includes naturally occurring antibodies as well as non-naturally occurring antibodies, including, for example, single chain antibodies, chimeric, bifunctional and humanized antibodies, as well as antigen-binding fragments thereof. Such non-naturally occurring antibodies can be constructed using solid phase peptide synthesis, can be produced recombinantly or can be obtained, for example, by screening combinatorial libraries consisting of variable heavy chains and variable light chains. These and other methods of making, for example, chimeric, humanized, CDR-grafted, single chain, and bifunctional antibodies are well known to those skilled in the art.
[0011] The term antigen refers to the molecules that can be recognized (bound) by an antibody. Antigens are most commonly polypeptides or carbohydrates, but they can also be lipids, nucleic acids, or even small molecules like neurotransmitters. A particular antibody molecule can typically only interact with a small region of an antigen and in the case of a polypeptide this is generally about 5-12 amino acids. This region can be continuous or it can be distributed in different regions of a primary structure that are brought together because of the secondary or tertiary structure of the antigen. The region of an antigen that is recognized by an antibody is called an epitope. A particular antigen may have one or more epitotic sites.
[0012] The term monoclonal antibody may include an antibody composition having a homogeneous antibody population derived from only one clone of cells, although the scope of the invention is not limited in this respect. In embodiments of the invention, the term monoclonal antibody is not limited to or by the source of the antibody, species, manner in which it is made, isotype, or structure.
[0013] As described more fully herein, composite organic inorganic nanoclusters (COINs) are composed of a metal and at least one organic Raman-active compound. Interactions between the metal of the clusters and the Raman-active compound(s) enhance the Raman signal obtained from the Raman-active compound(s) when the nanoparticle is excited by a laser. COINs according to embodiments of the present invention can perform as sensitive reporters for use in analyte detection. Since a large variety of organic Raman-active compounds can be incorporated into the nanoclusters, a set of COINs can be created in which each member of the set has a Raman signature unique to the set. Thus, COINs can also function as sensitive reporters for highly parallel analyte detection. Furthermore, not only are the intrinsic enhanced Raman signatures of the nanoparticles of the present invention sensitive reporters, but sensitivity may also be further enhanced by incorporating thousands of Raman labels into a single nanocluster and or attaching multiple nanoclusters to a single analyte.
[0014] It was found that aggregated metal colloids fused at elevated temperature arid that organic Raman labels could be incorporated into the coalescing metal particles. These coalesced metal particles formed stable clusters and produced intrinsically enhanced Raman scattering signals for the incorporated organic label(s). The interaction between the organic Raman label molecules and the metal colloids has mutual benefits. Besides serving as signal sources, the organic molecules induce a metal particle association that is in favor of electromagnetic signal enhancement. Additionally, the internal nanocluster structure provides spaces to hold Raman label molecules, especially in the junctions between the metal particles that make up the cluster. In fact, it is believed that the strongest enhancement is achieved from the organic molecules located in the junctions between the metal particles of the nanoclusters.
[0015] The nanoclusters can be prepared using standard metal colloid chemistry. Generally, the nanoclusters are less than 1 μm in size, and are formed by particle growth in the presence of organic compounds. The preparation of such nanoparticles also takes advantage of the ability of metals to adsorb organic compounds. Indeed, since Raman-active organic compounds are adsorbed onto the metal cluster during formation of the metallic colloids, many Raman-active organic compounds can be incorporated into a nanoparticle. Not only can COINs be synthesized with different Raman labels, but COINs may also be created having different mixtures of Raman labels and also different ratios of Raman labels within the mixtures.
[0016] Table 1 provides examples of the types of organic compounds that can be used to build COINs. In general, Raman-active organic compound refers to an organic molecule that produces a unique SERS signature in response to excitation by a laser. Typically the Raman-active compound has a molecular weight less than about 500 Daltons.
TABLE 1 Abbreviation Name Structure AOH Acridine Orange Hydrochloride CVA Cresyl Violate Acetate AFN Acriflavine Neutral DMB Dimidium Bromide TMP 5,10,1 5,20-Tetrakis(N-methyl-4- pyridinio)porphyrin Tetra(p- toluenesulfonate) TTP 5,10,1 5,20-Tetrakis(4- trimethylaminophenyl)porphyrin Tetra(p-toluenesulfonate) DAA 3,5-Diaminoacridine Hydrochloride PII Propidium Iodide (3,8-diamino-5-(3- diethylaminopropyl)-6- phenylphenanthridinium iodide methiodide MPI Trans-4-[4-(dimethylamino)styryl]-1- methylpyridinium iodide DAB 4-((4- (dimehtylamino)phenyl)azo)benzoic acid, succinimidyl ester
[0017] In general, COINs can be prepared by causing colloidal metallic nanoparticles to aggregate in the presence of an organic Raman label. The colloidal metal nanoparticles can vary in size, but are chosen to be smaller than the desired size of the resulting COINs. For some applications, for example, in the oven and reflux synthesis methods, silver particles ranging in average diameter from about 3 to about 12 nm were used to form silver COINs and gold nanoparticles ranging from about 13 to about 15 nm were used to make gold COINs. In another application, for example, silver particles having a broad size distribution of about 10 to about 80 nm were used in a cold synthesis method. Additionally, multi-metal nanoparticles may be used, such as, for example, silver nanoparticles having gold cores. In general, for applications using COINs as reporters for analyte detection, the average diameter of the COIN particle should be less than about 200 nm. Typically, in analyte detection applications, COINs will range in average diameter from about 30 to about 200 nm.
[0018] Antibody-based probe molecules may be adsorbed to the surface of the COINs or the COINs may be coated before antibody attachment. Typical coatings include coatings such as metal layers, adsorption layers, silica layers, hematite layers, organic layers, and organic thiol-containing layers. Typically, the metal layer is different from the metal used to form the COIN. Additionally, a metal layer can typically be placed underneath any of the other types of layers. Many of the layers, such as the adsorption layers and the organic layers provide additional mechanisms for probe attachment. For instance, layers presenting carboxylic acid functional groups allow the covalent coupling of a biological probe, such as an antibody, through an amine group on the antibody.
[0019] For example, COINs can be coated with an adsorbed layer of protein. Suitable proteins include non-enzymatic soluble globular or fibrous proteins. For applications involving molecular detection, the protein should be chosen so that it does not interfere with a detection assay, in other words, the proteins should not also function as competing or interfering probes in a user-defined assay. By non-enzymatic proteins is meant molecules that do not ordinarily function as biological catalysts. Examples of suitable proteins include avidin, streptavidin, bovine serum albumen (BSA), transferrin, insulin, soybean protein, casine, gelatine, and the like, and mixtures thereof. A bovine serum albumen layer affords several potential functional groups, such as, carboxylic acids, amines, and thiols, for further functionalization or probe attachment. Optionally, the protein layer can be cross-linked with EDC, or with glutaraldehyde followed by reduction with sodium borohydride.
[0020] In general, probes can be attached to metal-coated COINs through adsorption of the probe to the COIN surface. Alternatively, COINs may be coupled with probes through biotin-avidin coupling. For example, avidin or streptavidin (or an analog thereof) can be adsorbed to the surface of the COIN and a biotin-modified probe contacted with the avidin or streptavidin-modified surface forming a biotin-avidin (or biotin-streptavidin) linkage. Optionally, avidin or streptavidin may be adsorbed in combination with another protein, such as BSA, and/or optionally crosslinked. In addition, for COINs having a functional layer that includes a carboxylic acid or amine functional group, probes having a corresponding amine or carboxylic acid functional group can be attached through water-soluble carbodiimide coupling reagents, such as EDC (1-ethyl-3-(3-dimethyl aminopropyl)carbodiimide), which couples carboxylic acid functional groups with amine groups. Further, functional layers and probes can be provided that possess reactive groups such as, esters, hydroxyl, hydrazide, amide, chloromethyl, aldehyde, epoxy, tosyl, thiol, and the like, which can be joined through the use of coupling reactions commonly used in the art. For example, Aslam, M and Dent, A, Bioconjugation: Protein Coupling Techniques for the Biomedical Sciences , Grove's Dictionaries, Inc., (1998) provides additional methods for coupling biomolecules, such as, for example, thiol maleimide coupling reactions, amine carboxylic acid coupling reactions, amine aldehyde coupling reactions, biotin avidin (and derivatives) coupling reactions, and coupling reactions involving amines and photoactivatable heterobifunctional reagents.
[0021] Solid support, support, and substrate refer to a material or group of materials having a rigid or semi-rigid surface or surfaces. In some aspects, at least one surface of the solid support will be substantially flat, although in some aspects it may be desirable to physically separate'synthesis regions for different molecules with, for example, wells, raised regions, pins, etched trenches, or the like. In certain embodiments, the solid support may be porous. Solid substrate may include a bead, plate, tube, filter, particle, or any other suitable material and is not limited to composition, size, shape, or any other physical constraints.
[0022] Substrate materials useful in embodiments of the present invention include, for example, silicon, porous silicon, metal-coated surfaces, bio-compatible polymers such as, for example poly(methyl methacrylate) (PMMA) and polydimethylsiloxane (PDMS), glass, SiO 2 (such as, for example, a thermal oxide silicon wafer such as that used by the semiconductor industry), quartz, silicon nitride, functionalized glass, gold, platinum, and aluminum. Functionalized surfaces include for example, amino-functionalized glass, carboxy functionalized glass, and hydroxy functionalized glass. Additionally, a substrate may optionally be coated with one or more layers to provide a surface for molecular attachment or functionalization, increased or decreased reactivity, binding detection, or other specialized application.
[0023] Antibodies may be placed on the substrate surface in the form of an array. An array is an intentionally-created collection of molecules housed on a solid support in which the identity or source of a group of molecules is known based on its location on the array. The molecules housed on the array and within a feature of an array can be identical to or different from each other.
[0024] Embodiments of the present invention provide the ability to detect cross-functionality between specific antibodies and antigens generally not previously recognized as having binding affinity. Typically, antibodies from a specific species, such as goat, mouse, sheep, rat, rabbit, or hamster, have affinity toward antigens of the same species. In accordance with at least one or more embodiments, antibodies from a non-human species may be used to recognize antigens present in human serum. For example, existing libraries of antibodies can be used to identify the presence or absence of disease, such as cancer, in a human patient serum.
[0025] Monoclonal antibodies may be immobilized on to a solid substrate and exposed to human serum for a sufficient time to allow binding to antigens in the human serum. Subsequently, a binding event may be detected by utilizing Surface Enhanced Raman Spectroscopy (SERS) signals without requiring use of a label. In an alternative embodiment, monoclonal antibodies may be immobilized on to a solid substrate, exposed to human serum for a sufficient time to allow binding to antigens in the human serum, and then exposed for a sufficient time to allow binding to an antibody conjugated to COINS for performing a sandwich type assay. In another embodiment, polyclonal antibodies may be immobilized on a solid substrate, exposed to human serum for a sufficient time to allow binding to antigens in the human serum, and then exposed for a sufficient time to allow binding to antigens in the human serum. A binding event may be detected by utilizing SERS signals without requiring utilization of a label. In yet another embodiment, polyclonal antibodies may be immobilized on a solid substrate, exposed to human serum for a sufficient time to allow binding to antigens in the human serum, and then exposed for a sufficient time to allow binding to an antibody conjugated to COINS for performing a sandwich type assay. The resulting data may then be analyzed to compare one or more results between human serum from cancer patients and non-cancerous patients, and to determine information therefrom.
[0026] Numerous antibodies suitable for utilization in accordance with the present technology are available, both commercially available or currently being researched. For example, monoclonal antibodies are available from the Developmental Studies Hybridoma Bank (http://www.uiowa.edu/˜dshbwww/).
[0027] FIG. 1 provides a flow chart outlining a method for determining the degenerate binding ability of antibodies. To test the degenerate binding ability of the monoclonal antibody, the first step is to obtain and immobilize the antibodies on a solid substrate. Once the antibody is immobilized on the substrate, human serum is added and if the antibody is degenerate, it will bind to proteins in the human serum. The bound protein is detected using surface enhanced Raman scattering (SERS). To identify the bound protein, a label can be introduced, such as COIN, which is a metal nanoparticle aggregate that generates a unique SERS signal. The COIN may be conjugated with a detection antibody that recognizes the bound protein. The bound protein with COIN attached is detected using surface enhanced Raman scattering (SERS).
[0028] FIG. 2 show a diagram of degenerate binding in accordance with embodiments of the invention. An antibody is immobilized onto a solid substrate. Human serum is then added. If the antibody is degenerate it will bind to protein or other molecules in the human serum. The remaining serum is then washed from the surface of the substrate. The bound antigen is detected using surface enhanced Raman scattering (SERS). In FIG. 2 , to identify the bound protein, a label can be introduced, such as, for exmaple, COIN, which is a metal nanoparticle aggregate that generates a unique SERS signal, or a quantum dot. The COIN particle attaches to the bound antigen through, for example, detection antibody that recognizes a second epitope of the bound antigen. The bound antigen with COIN attached is detected using surface enhanced Raman scattering (SERS).
[0029] SERS of the substrate-attached antibody antigen complex can be performed for example, by depositing a solution of metal nanoparticles (such as, for example silver nanoparticles) on the surface of the substrate. The silver nanoparticle solution may optionally contain a signal enhancer, such as LiCl. The term metal or metal nanoparticles may in general refer to and may encompass any metallic structure which may include any structure made wholly, partially, in mixture, or in layers of metal, and which may include rough metal, metal colloids, metal nanoparticles, metal films, and metal coatings, although the scope of the invention is not limited in this respect. Additionally, metal-coated substrates, such as metal-coated silicon or metal-coated porous silicon can function as SERS substrates.
[0030] FIG. 3 shows a SERS spectrum from two different monoclonal antibodies, antibody 1 and antibody 2 . For antibody 1 , unique spectral features are observed when proteins in human serum bind to the antibody as compared to spectral features without human serum. Therefore, antibody 1 exhibits degenerate binding ability for proteins in human serum. However, for antibody 2 , no unique spectral features are observed when human serum is reacted as compared to spectral features without human serum, indicating that antibody 2 does not have degenerate binding ability for proteins in human serum.
[0031] To ensure that the SERS signal was not due to non-specific binding of the proteins in human serum to the substrate, experiments were conducted without the presence of antibodies. FIG. 4 shows that the SERS spectrum is relatively flat and does not contain the strong peaks observed in antibody 1 . This may serve as a reference to determine whether non-specific binding of proteins in human serum generate a SERS signal. | Embodiments of the present invention provide methods for determining the degenerate binding capabilities of antibodies. The methods provide information about degenerate binding capabilities without the use of involved procedures. Optionally, a molecule toward which an antibody exhibits degenerate binding ability may be identified through the use of a reporter, such as, a composite organic inorganic nanocluster (COIN). COINs are sensitive SERS (surface enhanced Raman spectroscopy) reporters capable of multiplex analysis of analytes. | 6 |
FIELD OF THE INVENTION
The invention relates to fluid flow regulating devices.
BACKGROUND OF THE INVENTION
The relationship between flow rate and pressure drop through a flow restriction has been employed to control flow rate. E.g., in Kates U.S. Pat. No. 3,402,735, fluid upstream and downstream of a flow restriction is exposed to opposite faces of a piston that is spring-biased in the direction of the upstream face and moves toward closing an outlet when displaced in the opposite direction owing to a temporary increase in the difference in pressure between the upstream face and the downstream face caused by increased flow.
SUMMARY OF THE INVENTION
It has been discovered that a fluid flow regulating device employing differential pressure on opposite sides of a movable piston can be made to very accurately control flow rate by using a closure member that has an externally curved surface that is movable between positions adjacent to and in front of an outlet orifice as the piston moves in response to changes in the magnitude of the difference in pressure on opposite sides of the piston. Because the closure member has an externally curved surface, when the outlet orifice is fully open, part of the closure member can be positioned in front of, but spaced from, the orifice, and only a small displacement of the closure member is necessary to fully block the orifice.
In preferred embodiments the closure member is a spherical ball; the spherical ball is rotatably mounted on a dowel connected to the piston by pivotal support members; a pair of guide ribs opposite the outlet orifice maintain the spherical ball in the vicinity of the outlet orifice; the piston is a plate having a restricted flow passage through it; an extension spring is used to bias the piston opposite the direction of flow; and the spring is connected to a support mounted on a threaded shaft so that the flow rate of the device can be easily adjusted by rotating the threaded shaft.
Other features and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The drawings will be described first.
DRAWINGS
FIG. 1 is an elevation, partially cut away, of a fluid flow regulating device according to the invention.
FIG. 2 is a vertical sectional view, taken at 2--2 of FIG. 1, of the FIG. 1 device.
FIG. 3 is a diagrammatic exploded perspective view of the FIG. 1 device showing the various components of it.
FIG. 4 is a horizontal sectional view of the FIG. 1 device, taken at 4--4 of FIG. 2.
FIG. 5 is a horizontal sectional view, taken at 5--5 of FIG. 2, of the FIG. 1 device.
FIGS. 6 and 7 are diagrammatic sectional views showing the piston and closure member of the FIG. 1 device in different positions.
STRUCTURE
Referring to FIG. 1, there is shown fluid flow regulating device 10 having inlet 12 and outlet 14 for receiving and delivering a fluid to be regulated. Extending from the inlet end of device 10 is slotted control rod 16 for adjusting the flow rate through device 10. Inlet 12 and outlet 14 are formed in plastic (ABS) housing 18.
Referring to FIGS. 2 and 3, it is seen that housing 18 is made of two pieces 20, 22 joined together by two-piece clamp 26 (FIG. 3) and retainer 28. Smooth portion 19 of slotted rod 16 is mounted for rotation in the end of housing piece 20 (FIG. 2), and threaded portion 30 of rod 16 extends into fluid passage 32. Rod 16 is prevented from moving into housing piece 20 by retaining clip 33 on the outside of housing 20, and is sealed to housing 20 by O-ring 34 and washer 36 on the inside.
Screwed onto threaded portion 30 is spring support 38, having slots 39 (FIG. 4) that engage longitudinal tracks 40, preventing rotation of support 38. The upper end of spring 42 (0.041" diameter, 316 stainless steel, 29±1 turns, 0.375" diameter) is held in hole 44 of member 38 by ring 46. The lower end of threaded portion 30 passes through the center of spring 42 (FIG. 2). The lower end of spring 42 is hooked around extension 48 of piston plate 50.
Piston plate 50 is 1.250" in diameter and has restricted flow passage 52 (0.054" diameter, 0.25" long) passing through it. On the other side of piston plate 50 from extension 48 is cylindrical support 54 formed around the outlet of restricted flow passage 52. Support 54 has a pair of slots 55, through which passes upper dowel 56 of H-shaped ball carrier 58, which includes legs 60 and a cross-member 62. At the lower ends of legs 60 is lower dowel 64, on which is supported spherical plastic closure member 66 (0.187" diameter Teflon TFE).
On the upstream surface of piston plate 50 is diaphragm 68 (1.625" diameter, 0.020±0.001" thick silicone rubber, 40-60 Durometer), which is retained on the upper surface of piston plate 50 by retaining ring 70. The periphery of diaphragm 68 is sealed between housing pieces 20, 22 along with rubber O-ring 72. The diameter of the flow passage where pieces 20, 22 are joined is 1.375".
As is seen best in FIGS. 6 and 7, formed in the bottom of housing piece 22 is outlet orifice 74 (0.062±0.001" diameter). Opposite outlet orifice 74 (FIG. 5) are pair of guide ribs 76 spaced by 0.150" and positioned to retain spherical closure member 66 within the vicinity of outlet orifice 74.
Operation
In operation, e.g., in regulating flow of dialysate in a dialysate preparation machine, fluid flows into inlet 12, through passage 32 and out of outlet 14. In traveling through passage 32, fluid flows through restricted passage 52 of piston plate 50, undergoing a pressure drop that is a function of the flow rate through device 10. This creates a difference in pressure at the upstream surface of piston plate 50 (above diaphragm 68) and at the downstream surface of piston plate 50, creating a net force on piston plate 50 in the downstream direction.
When the net force owing to differential pressure on piston plate 50 is less than the force of spring 42, plate 50 rests against housing piece 20, as shown in FIG. 7. As flow increases, the differential force on piston plate 50 equals the force on spring 42, and flow control begins, with piston plate 50 moving toward the outlet end of device 10, and spherical closure member 66 rolling closer to and extending partially in front of orifice 74, but not preventing flow into outlet orifice 74. Closure member 66 is automatically aligned with orifice 74, owing to water flowing past it into outlet orifice 74. If there is an increase in flow through restricted passage 52, a larger pressure drop results, causing further downstream displacement of piston plate 50, in turn causing closure member 66 to roll directly in front of outlet orifice 74, and to be sucked into orifice 74, as shown in FIG. 6. This temporarily restricts the flow, decreasing the pressure drop and causing the piston to move upstream, and the outlet orifice to be uncovered, holding the flow constant. Because closure member 66 has an externally curved surface, when orifice 74 is fully open, part of closure member 66 can be positioned in front of, but spaced from, orifice 74. As closure member 66 need only travel 1/2 the diameter of outlet orifice 74 to go from a fully open position to a fully closed position, very sensitive throttling is provided. If large flows cause plate 50 to be forced all the way against housing piece 22, member 66 is not forced to go past orifice 74, because it is sucked into orifice 74, dowel 56 remaining stationary in slot 55 while piston plate 50 continues moving. Movement of diaphragm 68 with piston 50 does not involve any force.
By rotating rod 16, spring support 38 moves along threaded portion 30, thereby adjusting the force on spring 42 which counteracts the differential force on piston plate 50 and the flow rate that results. The use of extension spring 42 avoids problems associated with buckling of compression springs and inaccuracies caused thereby.
Device 10 provides constant flow over a wide pressure range, because increases in total pressure drop over device 10 (e.g., caused by increased inlet pressure and constant outlet pressure) are taken up by the pressure drop at outlet orifice 74 and not at restricted flow passage 52. During flow control, in addition to the differential pressure force on piston 50, the force of spring 42 is resisted by the force pulling spherical closure member 66 toward outlet 74 (transmitted through legs 60). An increase in the total pressure drop in device 10 causes spring 42 to extend, and closure member 66 to move toward outlet 74, in turn increasing the pressure drop there by partially blocking orifice 74. At the same time, closure member 66 is sucked partially into orifice 74 as its center goes beyond the edge of orifice 74, greatly increasing the force exerted by it on spring 42 through legs 60. Thus, the ability of the closure member to increase the pressure drop at the outlet orifice when an increased pressure drop is imposed on the overall device makes it less likely that the increase in pressure drop on the overall device will be taken up at the restricted flow passage, something that would tend to increase flow rate.
Device 10 also is insensitive to particulate contamination at outlet orifice 74 (as clogging of orifice 74 automatically causes a smaller flow rate and differential pressure, in turn causing closure member 66 to uncover orifice 74). With the exception of restricted flow passage 52 and the pressure drop at outlet orifice 74, there are small pressure losses in fluid flow through device 10.
Other Embodiments
Other embodiments of the invention are within the scope of the following claims. For example, in addition to being spherical, the closure member can have another shape involving an externally curved surface; e.g., the closure member could be cylindrical. | A fluid flow regulating device comprising a housing defining an inlet, an outlet orifice, and a fluid flow passage therein between the inlet and the outlet orifice, a movable piston in the housing having an upstream surface and a downstream surface exposed to fluid flowing through the passage, means for providing a drop in pressure between the upstream surface and the downstream surface as a function of fluid flow rate through the device, and a closure member that is connected to the movable piston and has an externally curved surface that is movable between positions adjacent to and in front of the outlet orifice as the piston moves in response to changes in the magnitude of the drop in pressure. | 8 |
This application is a division of application Ser. No. 07/643,525, filed Jan. 18, 1991, now U.S. Pat. No. 5,121,536.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to methods and apparatus for strengthening columns or elongate tubes, and more specifically for strengthening spring reinforced catheters and other surgical access devices.
2. Discussion of the Prior Art
It is often desirable to increase the strength of elongate columns or tubes, such as tubes formed from flexible plastics. Ordinarily one would increase the wall thickness of the tube in order to provide increased strength, but in some cases there are limitations on the maximum diameter which can be tolerated. Such is the case with medical catheters which require the smallest possible outer diameter.
For such catheters, it has been found desirable to form the plastic tube over a spring thereby increasing the column strength of the catheter without sacrificing either flexibility or size. The modulus of such a combination has exceeded the sum of moduli associated with the spring and the tubing.
Spring reinforced catheters have been made from several processes all of which require the application of externally generated heat. Most commonly, the spring has been inserted into the bore of flexible polyvinylchloride tubing which is then heat shrunk so that it collapses onto the spring This is a complex process and somewhat restricted as to the materials which can be used for the tubing.
Coextrusion has also been used to manufacture spring reinforced catheters. In this process, the spring is deployed through an extruder as the molten plastic is formed around the spring. Molding processes have also been used for relatively short lengths of tubing.
In all of these methods of manufacture, heat must be applied to the tubing in significant quantities in order to effectively melt or otherwise shrink the tubing onto the spring. In its melted state, the tubing forms a sheath over the spring which is essentially free of stress due to the applied heat. This results from the fact that any stresses in the tubing are essentially relieved by the heat. The resulting structure has a relatively low modulus. Each of these methods of manufacture requires complex machinery for coextrusion, heat shrinking or molding; in addition, the related processes are extensive and must be carefully controlled.
Particularly in a catheter construction, the tubing must meet several requirements. For the processes of the prior art, it is desirable that the material be shrinkable or at least heat formable. It is desirable that it have a high tensile strength and good flexibility. Complex catheters, requiring balloons or thermistors or other associated structures, also require that the tubing material be solvent bondable.
Polyvinylchloride, polyethylene, urethanes and nylon can all be heat shrunk, but each of these materials fail to meet one or more of the forgoing criteria.
SUMMARY OF THE INVENTION
These shortcomings of the prior art are overcome in the present invention by a new process for forming spring reinforced tubing and a material particularly adapted to this process and the requirements for catheter construction.
"Hytrel®" is a trademark of E. I. duPont de Nemours & Co. and is applied to a material which is solvent bondable, flexible, heat formable, and has a high tensile strength. Although this material is not particularly heat shrinkable, it can be longitudinally stretched at normal room temperatures without the application of significant heat. By merely fixing one end of a tube of Hytrel® and grasping the other end of the tube, a tensile stress can be applied to the material which will cause the tube to neck-down, thinning the walls of the tube and decreasing the internal diameter of the bore. This transformation occurs at a zone of transition which progresses along the tube as it is stretched. This process will be referred to herein as "cold extrusion."
It is of particular significance that the stretching of the tubing imparts internal stresses which cause the tubing to shrink slightly thereby imparting the stresses to the internal spring. This results in a substantial increase in the column strength of the catheter, an increase which can be measured in the modulus of the combination.
One aspect of the invention includes a method for making a spring reinforced catheter including the steps of providing an elongate tube defined by a proximal end and a distal end, the tube having an interior bore with an inside diameter; providing a spring having a proximal end, a distal end, and an outside diameter less than the inside diameter of the bore of the tube; inserting the spring at least partially into the bore of the tube; marginally increasing the temperature of the tube at a particular location along the tube relative to the temperature of the remainder of the tube; and stretching the tube at the particular location to reduce the diameter of the interior bore of the tube.
In another aspect of the invention, the method includes the steps of increasing the temperature of the tube at a particular location, drawing the walls of the tube onto the spring at the particular location and exothermically heating the tube at progressive locations along the remainder of the tube.
In still a further aspect of the invention the method includes the steps of stretching the tube to draw the walls of the tube radially inwardly into heat transferring contact with the spring and heating the tube at positions progressing axially from the particular location.
The resulting spring reinforced catheter includes a spring having a longitudinal configuration and a first modulus in its unreinforced state, a sheath overlying the spring and axially compressing the spring to a second state wherein the spring has second modulus greater than the first modulus.
These and other features and advantages of the invention will be more apparent with a description of preferred embodiments and reference to the associated drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side-elevation view of a cold extrudable tube;
FIG. 2 is a side-elevation view of an unreinforced spring;
FIG. 3 is a side-elevation view illustrating the process step of inserting the spring into the tube in a preferred method of the invention;
FIG. 4 is a side-elevation view of a process step whereby a portion of the tube is cooled with a sprayed fluid;
FIG. 5 is a side-elevation view illustrating a step of wiping the tube with an evaporative agent;
FIG. 6 is a side-elevation view illustrating the step of heating a portion of the tubing;
FIG. 7 is a side-elevation view illustrating the step of grasping one end of the tubing and heating the tubing where it is grasped;
FIG. 8 is a side-elevation view illustrating the step of grasping the tubing at the respective ends of the tubing;
FIG. 9 is a side-elevation view illustrating the step of stretching the tubing with the spring at least partially disposed in the bore of the tubing;
FIG. 10 is a side-elevation view illustrating the step of stretching the tubing using a hand thereby causing the tubing to neck-down onto the spring;
FIG. 11 is a side-elevation view illustrating a transition region which progresses along the tubing in a preferred process of the invention;
FIG. 12 is a side-elevation view illustrating the internal stresses of the tubing which axially compress the spring;
FIG. 13 is an enlarged view of the axially compressed spring of FIG. 12;
FIG. 14 illustrates apparatus for testing the modulus of a spring reinforced catheter; and
FIG. 15 is a side elevation view of an exterior tube cold extruded over an interior tube.
DESCRIPTION OF PREFERRED EMBODIMENTS
A tube is illustrated in FIG. 1 and designated generally by the reference numeral 10. The tube 10 can have substantially any dimension but for most purposes will have a high aspect ratio such that its length is substantially greater than its cross-sectional dimension. The tube 10 will typically be cylindrical about an axis 11 and will include walls 12 extending radially between an outside diameter and an inside diameter of the tube 10. The walls 12 define an inner bore 14 which extends axially between a distal end 16 and a proximal end 18 of the tube 10.
In accordance with a preferred method and embodiment of the invention, the tube 10 is formed from a material which can be cold extruded. That is, the ends 16 and 18 of the tube can be separated at room temperature stretching the tube along the axis 11. During the stretching the walls 12 of the tube 10 neck down decreasing both the inside diameter and outside diameter of the tube. It follows that both the thickness of the walls 12 and the diameter of the bore 14 are decreased in this process of cold extrusion.
A spring is illustrated generally in FIG. 2 and designated by the reference numeral 21. The spring 21 is formed from a wire 24 typically having a circular cross-section and being wound into spring convolutions 27 adjacent pairs of which may be contacting. The convolutions 27 provide the spring 21 with an outside diameter less than the diameter of the tube 10, as well as an inside diameter which characterizes a hollow passage 30 extending axially of the spring 21. The wire 24 will typically be formed from stainless steel and will have a cross-sectional diameter of 0.005 inches. In a preferred method involving catheter construction, the tube has an outside diameter of 0.039 inches, and an inside diameter of 0.018 inches; the spring 21 is characterized by an outside diameter of 0.016 inches and an inside diameter of 0.006 inches.
Materials which can be cold extruded include nylon; however, this material is generally unsuitable for complex catheter construction because it is not solvent bondable. A preferred material is manufactured by DuPont and sold under the trademark "HYTREL®". This material is not only cold extrudable but also solvent bondable. It provides a high tensile strength and flexibility which is particularly appreciated in catheter construction. It is also heat deformable. The more common materials found in the art of catheter construction, namely polyvinylchloride, polyethylene and urethanes, are not particularly susceptible to cold extrusion and therefore do not benefit as much from the present concept.
In a preferred method of manufacture, the tube 10 is axially stretched causing the tube to neck down initially at the point of greatest weakness. This point will usually be at a particular location along the tube 10 where the temperature is the highest. In this region the tube 10 will first yield to the stresses associated with stretching.
While the process could proceed without regard to the initial position of that transition region, it may be desirable to dictate that position by initially locating the transition region at a preferred position such as the proximal end 16 of the tube 10. In FIG. 4 this particular location is designated generally by a bracket 32. It is desirable that the temperature of the tube 10 at this particular location 32 be relatively greater than the temperature of the remainder of the tube 10 which is designated by the bracket 34.
One way of relatively heating the particular location 32 is to cool the remainder 34 of the tube 10. This can be accomplished by spraying the remainder 34 with cold air 36 from a nozzle 38 as illustrated in FIG. 4. Another way of cooling the remainder 34 of the tube is to wipe the tube in that region with an evaporative agent 41, such as alcohol, using a cloth 43 or other absorbent material. This wiping step is illustrated in FIG. 5. Neither the air 36 illustrated in FIG. 4 nor the evaporative agent 41 illustrated in FIG. 5 is intended to contact the particular location 32. By thus cooling the remainder 34 of the tube 10, the particular location 32 is relatively heated making this region 32 most susceptible to deformation by stretching.
Another way of relatively heating the particular location 32 is to provide an external heat source such as a current heated wire 45 illustrated in FIG. 6. In this case the heat is applied directly to the particular location 32 and intentionally omitted from the remainder 34 of the tube 10.
In a preferred method and apparatus associated with the present invention, the tube 10 is formed of Hytrel® material which does not require a significant temperature differential between the particular location 32 and the remainder 34 of the catheter 10. In fact, if the remainder 34 is maintained at room temperature, the particular location 32 can be sufficiently heated by merely grasping the tube 10 between the thumb and index finger of a hand 47. This will impart body heat to the particular location 32 without raising the temperature of the remainder region 34. With this process, as illustrated in FIG. 7, the temperature of the particular location 32 approaches skin temperature of the hand 47.
If it is desirable to relatively heat the particular location 32 . . . which is the same as relatively cooling the remainder region 34 . . . some differential in temperature must be achieved. If room temperature is substantially the same as skin temperature, about 98.6° F., the process illustrated in FIG. 7 will not be as effective as the cooling processes illustrated in FIGS. 4 and 5 or the heating process illustrated in FIG. 6. It has been found that when the room temperature is less than 87° F., a suitable temperature differential can be established with body heat as illustrated in FIG. 7.
In axially stretching the tube 10, it is desirable that the ends 16 and 18 of the tube 10 be held in a device or other holding apparatus illustrated by the arrows 49 and 52 in FIG. 8. These holding apparatus 49 and 52 can then be separated to stretch the tube 10. For example, the holding apparatus 49 can be maintained in the fixed location and the holding apparatus 52 moved axially away from the apparatus 49 as illustrated by a pair of arrows 54.
FIG. 9 also illustrates another advantage associated with the preferred method. If the spring 21 is merely inserted into the bore 14 and the ends 16, 18 of the tube 10 are separated, one will not necessarily know where the spring 21 ends up in the tube. However, if the spring 21 is grasped or otherwise held along with the end 16 of the tube, its location will always be determinable in the final product.
Thus as illustrated in FIG. 10, the hand 47 provides the means for grasping the distal end 16 of the tube 10, means for heating the distal end of the tube 10, as well as means for retaining the spring 21 in a predetermined location along the tube 10.
As the tube 10 is stretched, it begins to deform in a relatively short transition region 54. An enlarged view of this region is presented in FIG. 11 where the region 54 is illustrated to include a first zone A, a second zone B, and a third zone C. The first zone A is characterized by the walls of the tube 12 having a temperature (such as room temperature) and being spaced from the spring. The second zone B is characterized by the tube walls 12 having a second temperature (which may be slightly higher than room temperature) and being in substantial contact with the spring 21. The zone C is disposed between zone A and zone B. In zone C, the tube walls 12 are characterized by a third temperature greater than either the first temperature associated with zone A or the second temperature associated with zone B. The diameter of the walls 12 in zone C is less than the diameter of the walls in zone A but greater than the diameter of the walls in zone B.
Zone B is disposed from zone A in a particular direction such as the distal direction of the tube 10. When the tube 10 is drawn axially as illustrated in FIG. 10, the transition zone 54 initially starts in the particular location 32 and then moves proximally along the tube 10 until the entire spring 21 is disposed in zone B.
The temperatures of the respective zones A, B, and C are particularly critical to an understanding of the cold extrusion process. As the tube 10 is initially heated in the particular location 32, the tube first deforms in this area as the enlarged tube of zone A transitions through zone C into contact with the spring 21 in zone B.
As a result of this initial physical deformation, work occurs in an exothermic reaction which heats areas of the tube adjacent to the particular location 32. This heat which occurs primarily in zone C is given up to the spring 21 when the walls 12 contact the spring in zone B. It follows that the temperature of the walls in zone B will be slightly higher than the room temperature associated with the spring 21. Continued axial tension on the tube 10 will deform the tube at the next point of weakness which will be in the area of the tube which has been heated by the mechanical exothermic reaction but has not yet passed that heat to the spring 21. This occurs in the zones A and C of the transition region 45.
If the tube 10 is grasped at the distal end 16 and drawn distally, a series of points 56, 58 and 61 disposed proximally along the tube 10 will individually and progressively pass through the zones A, C and B (in that order) as the transition region 54 moves proximally along the tube 10.
In a preferred method of manufacture, the Hytrel® tubing is loaded at temperatures below 100° F. and cold extruded or drawn at a rate of about 1/10 inch per second. This cold extrusion tends to elongate the tube 10 by a factor of three to four while reducing the inside diameter of the tube 10 by a factor of about two.
When the tensile stretching force is stopped, the cold extruded tubing 10 tends to relax by as much as 1% to 5% of its length. This commonly occurs when tension is applied to any material, as the stretching tends to develop internal stresses which attempt to draw the material back to its original configuration when the tension is relieved. These internal stresses are of particular importance to the preferred methods and embodiments of the invention. It is these internal stresses which urge the tube 10 to shorten its length. Were it not for the presence of the spring 21 and the intimate contact between the walls 12 and the convolutions 27 of the spring 21, the tube 10 would actually exhibit a shortened axial dimension.
In a preferred method wherein the adjacent convolutions 27 of the spring 21 are initially contacting, the spring 21 cannot be further compressed, so the internal stresses of the tube 10 are actually transferred to the spring 21 thereby increasing the column strength or modulus of the spring.
In the enlarged view of FIG. 13, the internal stresses are represented by arrows 65. These stresses are communicated through the walls 12 which may form a slight ridge 66 between each adjacent pair of the convolutions 27. These ridges 66 tend to press against the adjacent convolutions 27 thereby imparting the internal stresses to the spring 21.
The internal stresses offer a significant advantage to the present invention as can be appreciated with reference to FIG. 13 which illustrates a typical test for column strength or modulus. An elongate column such as the reinforced spring 21, is laid across two supports 67 and 69, and a force P is applied to the object intermediate the supports 67 and 69. The amount of deflection which results from the force P provides an indication as to the modulus or stiffness of the object. This modulus considers not only the magnitude of the force P and the distance separating the supports 67, 69, but also the cross-sectional area of the object.
The modulus of elasticity for a tube is given by the following Formula I: ##EQU1## where L is the length between the supports 67, 69;
f is the deflection of the tube; and
P is the force applied to the tube intermediate the supports 67, 69.
Using this formula to calculate the modulus for a 2 Fr. catheter formed of Hytrel® cold extruded over a stainless steel spring, the combination having an outside diameter of 0.027 inches and inside diameter of 0.008 inches, indicates that the modulus of elasticity for this combination is 1,240,000 psi. In order to appreciate the significance of this figure one would have to test the catheters of the prior art using the same formula. Such a test has indicated that polyethylene tubing heat shrunk over the same spring produces a 2 Fr. catheter having a modulus of only 573,000 psi. Thus the cold extrusion process provides a modulus which is more than twice as high as that associated with the catheters of the prior art. This of course translates into axial stiffness, as well as better pushability and torquability for the catheter.
If one were to calculate the modulus of the unreinforced tube 10, and the modulus of the unreinforced spring 21, the prior art which combines these two elements would show a modulus which is perhaps 400% greater than the sum of the moduli associated with these two components. Thus even the shrink tubing or coextrusion methods of the prior art provide some increase in strength for the reinforced column. However, with the cold extrusion concept of the present invention, the modulus can be increased by as much as 800% in order to provide a desired stiffness without sacrificing the increased size of the catheter. Catheters embodying this concept and having a diameter of only 2 Fr. have exhibited a modulus greater than 1,000,000 psi.
It will be appreciated that the spring 21 is merely a preferred embodiment of a cylindrical core element that can be prestressed by the cold extrusion of an outer tube 10. In the case of the spring 21, the convolutions 27 provide a corrugated outer surface which tends to increase the coefficient of friction between the tube 10 and the spring 21. This coefficient of friction can be important in order that the axially compressing tube 10 does not slip on the spring 21 but rather engages the spring 21 to axially stress this cylindrical core element.
In a more generic embodiment, this cylindrical core element comprises a second tube 73 disposed in the bore of the outer sheath or tube 10. An irregular outer surface 75 can be provided to increase the coefficient of friction between the tube 10 and the element 73. Typically the core element 73 will have a modulus greater than the tube 10 in order to provide maximum stiffness. For example, the core element 73 may be formed of polytetrafluoroethylene and provided with a tubular configuration. This embodiment will be of particular advantage where the catheter requires a smooth inner surface 77.
Although specific preferred embodiments of the concept have been disclosed, it will be apparent that both the methods and embodiments of the invention can be otherwise characterized. Other materials may be applicable to the cold extrusion process and facilitate the formation of reinforced springs without expensive heat shrink or coextrusion machinery. Other methods for heating and cooling particular regions of the tube 10 will also be apparent to those skilled in the art. For these reasons, the scope of the invention should not be ascertained with reference only to the drawings or even the particular embodiments described, but should be determined only with reference to the following claims. | A catheter includes a spring having a plurality of convolutions disposed along a longitudinal axis, and a first modulus. A sheath overlying the spring engages the convolutions of the spring and imparts to the spring axial compressive stresses which increase the modulus of the spring. The catheter can be manufactured by inserting the spring into a tube of Hytrel® material, stretching the tube at a transition region which advances along the tube causing the tube to neck down onto the spring. The stretching develops internal stresses which are ultimately imparted to the spring thereby increasing the modulus of the catheter. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a poppet valve actuator apparatus for opening and/or closing valves of various types, and more particularly, to a valve actuator which is powered or controlled by any suitable means, such as pneumatic or hydraulic fluids, electrical power or by manual operation. While the invention is particularly suitable for use with and is described in connection with a tapered plug type of poppet valve formed of "Teflon" plastic material, the valve actuator of the present invention may also be utilized with a wide variety of valves of different types.
2. Description of the Prior Art
Various types of actuators have heretofore been employed for tapered plug valves formed of "Teflon" plastic material. In general these actuators have been of the so-called impact type and do not provide a consistent closing force that is needed to insure a predictable progressive penetration and leak-tight closure of the tapered plug against the seat over the useful life of the valve. Impact actuators operate on the principle of the application of stored spring energy (usually with a normally closed valve) and pneumatic energy (usually with a normally open valve), through conversion to kinetic energy and force recovery through an anticipated deceleration rate. With these impact units pneumatic venting/pressurization rates, and piston and stem seal friction, often varying with wear, and lubrication, temperature and seal differential pressure cannot be controlled sufficiently to insure acceptable performance. Deceleration forces vary with plug alignment during seating and the depth of plug penetration into the seat. Contamination and temperature variation of the valve material further influence the final force value of seating and closing and vary widely. Impact actuators also suffer from a so-called "first cycle stick" problem wherein sliding devices (especially seals) tend to stick after being maintained in a fixed position for a long period of time.
Patents which are generally pertinent to the present invention are the Stouder U.S. Pat. No. 2,752,930, the Snyder U.S. Pat. Nos. 4,074,688 and 4,073,466, the Goehring U.S. Pat. No. 2,564,569, the Mueller U.S. Pat. No. 3,593,958 and the Weber U.S. Pat. No. 983,101.
SUMMARY OF THE INVENTION
The above-discussed disadvantages of impact type actuators for tapered plug valves are avoided in accordance with the present invention by providing a relatively high value, repeatable valve closing force which is momentarily applied to a valve plug formed of material such as "Teflon" plastic to insure positive initial insertion and progressive penetration into the valve seat, independent of manually applied force, spring force, pneumatic pressure or the rate of valve closure. After the valve plug is closed, the holding force acting on the plug to maintain it in a closed position automatically drops to a selectively controlled, lesser value, moderate holding force that positively retains the plug with ample seating pressure but low enough to minimize long term deformation or creep of the "Teflon" material of the valve poppet itself. For valve opening, the actuator of the present invention provides a high value unseating force to positively withdraw the plug and fully open the valve.
OBJECTS OF THE INVENTION
It is, therefore, an object of the present invention to provide a new and improved valve actuator wherein a high value, accurately repeatable closing force is momentarily applied to a valve poppet, and after closure, the force on the poppet is automatically reduced to a lower value which is sufficient to maintain the valve poppet tightly sealed, but is low enough to minimize any substantial deformation of the valve poppet material.
It is another object of the present invention to provide a new and improved valve actuator for a poppet type valve which is capable of producing an accurately repeatable, high initial closing force on a valve poppet followed by a reduced and selectively controlled holding force for long term retention of the valve in a closed position.
It is a further object of the present invention to provide a new and improved valve actuator which can be economically manufactured and which provides a highly reliable and repeatable closure force for a tapered plug type valve poppet formed of plastic material such as "Teflon.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings in which:
FIG. 1 is a sectional side elevational view of a valve actuator according to the present invention for use in connection with a normally open tapered plug type valve;
FIG. 2 is a view similar to FIG. 1 but showing the valve in the position in which a high value, initial closing force is applied to the tapered valve plug;
FIG. 3 is a view similar to FIG. 1 but showing the valve actuator in a position wherein a reduced holding force is applied to the fully seated tapered valve plug; and
FIG. 4 is a cross-sectional view of an alternative arrangement of the present invention for a normally closed, tapered plug type valve poppet.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 to 3 of the drawings, the present invention is therein illustrated in connection with a poppet valve having a frustoconically tapered plug 10 preferably formed of "Teflon" plastic material and adapted to be seated against an annular valve seat 12 formed at the lower end of a housing, which is indicated generally at 14. The valve poppet 10 is connected to one end of an elongated valve stem 16 which is journaled for sliding longitudinal movement along the central axis of the housing 14. The upper end of the valve stem 16 extends through a top or upper end wall 18 of an upper housing section 20 secured to the lower housing 14. Both housings 14 and 20 are provided with outwardly extending annular flanges or lips 22 and 24 between which is secured an outer edge portion of a flexible diaphragm 26. The lips 22 and 24 are sealed together in a suitable manner to provide a control chamber 28 and a lower chamber 30 which are separated by means of the flexible diaphragm 26.
The actuator mechanism for the poppet 10 includes a piston indicated generally at 32 and the piston includes a downwardly extending annular skirt 34 which is adapted to receive and contain the upper end of a main actuating spring 36. The opposite end of the spring is seated in the bottom of an annular recess 38 formed in an intermediate transverse wall of the housing 14.
The valve stem 16 is formed with an annular shoulder 40 defined between upper and lower sections and the surface of the shoulder supports a sleeve 42 retained on the valve stem 16 by a nut 44 threaded onto the upper end section. The valve stem 16 and actuator 32 are interconnected by means of a detent assembly comprising a plurality of balls 46 positioned equilaterally around the outer periphery of the sleeve 42 and biased into corresponding conically shaped recesses in the outer surface of the sleeve by radially positioned coil springs 48. When the balls 46 are seated in the conical recesses of the sleeve 42 as in FIGS. 1 and 2, the stem 16 and sleeve are locked together and move in unison. When the balls are not seated in the recesses as shown in FIG. 3 the stem 16 may slide relative to the sleeve 42 in the central bore thereof.
The inner edge of the annular flexible diaphragm 26 is sandwiched between an annular holding plate 50 and an intermediate radial wall 52 of the actuator 32 so as to provide a sealed actuating pressure chamber 28 into which fluid may be admitted under pressure through an inlet passage 54 in the wall 18 in order to close the valve. A coil spring 56 for providing a reduced value holding force for maintaining the valve in a closed condition after initial seating is mounted between an outwardly extending radial flange 58 on the upper end of the sleeve 42 and a top wall 60 of an upwardly extending cup-like portion 62 on the actuator 32.
In order to shield the lower end of the stem 16 from fluid which may be corrosive that is flowing through the opened valve between the valve seat 12 and a port 64 on a sidewall of the valve chamber, a flexible bellows 66 is provided to seal between the valve member and the actuator mechanism thereof. The bellows 66 is connected to an outwardly extending flange portion 68 at the lower end of the valve stem 16 and the top of the bellows is sealed to a flange portion 70 of the housing 14. In addition, an O-ring 72 is mounted in a groove in the lower end portion of the stem to seal between the valve stem and the bore in contact therewith. An upper end 74 of the valve stem 16 is sealed in sliding engagement with a bore formed in the upper end wall 18 of the housing section 20, and an O-ring 76 is mounted in a groove in an upper portion of the valve stem for this purpose.
Considering now the principles of operation of the positive force poppet valve actuator of the present invention, when the valve is open (FIG. 1), the main actuator spring 36 moves the actuator piston 32 upwardly until the top end wall 60 engages the under side of the upper end wall 18 of the upper housing 20. In this position, the holding spring 56 forces the radial flange portion 58 on the valve stem 16 into engagement with the radial intermediate wall 52 of the actuator 32 so that the balls 46 are seated within their respective recesses in the tubular body of the sleeve 42.
When the pressurized fluid is now admitted to the control chamber 28 no downward movement of the valve stem 16 is produced until the fluid pressure within the chamber 28 produces a downward force on the actuator 32 that exceeds the upward force of the main actuator spring 36. However, as soon as the fluid pressure force in the control chamber 28 is sufficient to overcome the upward force of the spring 36, the actuator 32 begins to move downwardly and because the valve stem 16 is positively interlocked with the actuator 32 by means of the balls 46 seated in their respective recesses as a detent mechanism, the poppet 10 is moved downwardly into closing engagement with the annular seat 12 to the closed or seated position as shown in FIG. 2. As the fluid pressure continues to build up in the chamber 28 an increasing seating force is exerted on the poppet 10 to insure positive seating in the valve seat 12. This seating force continues to increase until the detent mechanism functions to disconnect the actuator 32 from the valve stem 16 as the balls 46 are moved radially outward from their respective recesses. When this occurs, the actuator 32 is slidable and moves downwardly with respect to the valve stem 16. The balls 46 ride along the outer surface or periphery of the sleeve 42 until the bottom edge of the actuator skirt 34 is moved into engagement with an annular stop surface or shoulder 80 formed on an intermediate transverse wall of the housing 14, as shown in FIG. 3.
As soon as the actuator 32 is disconnected from the valve stem 16 and the skirt 34 moves downwardly into engagement with the shoulder 80, the force tending to hold the poppet 10 against the seat 12 is reduced to a lower value that is provided by the auxiliary holding spring 56 even though the fluid pressure in the control chamber 28 continues at a high value which originally caused the detent mechanism to disconnect the actuator 32 from the valve stem 16.
After seating, the valve poppet is retained in the closed position by a reduced holding force substantially less than the value of the force used to initially close or seat the tapered poppet 10. Long term deformation and/or creep or cold flow of the material of the poppet 10 is prevented or greatly reduced by the reduced holding force provided by the spring 56 and this permits excellent sealing action to be achieved even though the normally open valve may be closed for extended periods of time.
In this connection it is pointed out that the force with which the poppet 10 is initially seated on the seat 12 is accurately controlled and limited by the detent mechanism rather than the main actuator spring 36. If, for example, it is desired to initially seat the poppet 10 with a force of from sixty to eighty pounds, the springs 48 are sized so that the balls of the detent mechanism will move out of the recesses to release the sleeve on the stem at this value of seating force exerted on the stem.
Under these assumed conditions, the main actuator spring 36 may exert a force of forty pounds on the stem, but this only means that the actuator 32 will not start moving downwardly from the position shown in FIG. 1 toward the position shown in FIG. 2 until the fluid pressure in the control chamber 28 overcomes the spring force. However, the pressure in the chamber 28 may continue to rise to exert a seating force of sixty to eighty pounds for seating the poppet 10 in the annular valve seat 12, and this force value may occur before the detent mechanism disengages the actuator 32 from the valve stem 16 and moves the actuator to the position shown in FIG. 3. When the actuator moves to the position shown in FIG. 3.
When the actuator moves to the position shown in FIG. 3, the holding force with which the poppet 10 is retained on the seat 12 is reduced to a value of twenty to thirty pounds which is exerted by the holding spring 56. At this lower force value, cold flow of the "Teflon" poppet 10 is prevented or eliminated even though the valve is retained in the closed position over long periods of time.
In order to open the valve poppet 10, the port 54 is vented to atmosphere, and the pressure in the chamber 28 is reduced until the force of the main actuator spring 36 is sufficient to move the actuator 32 upwardly so that the detent mechanism again interconnects the actuator 32 with the valve stem 16. After the balls are seated, the poppet 10 is withdrawn from the seat 12 to open the valve. With this arrangement, a high value plug unseating force is provided to positively withdraw the plug 10 and fully open the valve.
In FIG. 4 is illustrated an alternative embodiment of the present invention which is suitable for controlling a normally closed tapered plug type of poppet valve. In this embodiment, identical reference numerals have been used for corresponding elements of the embodiment heretofore described in connection with FIGS. 1 to 3.
Referring to FIG. 4, a normally closed valve of this embodiment is generally similar to the normally open valve heretofore described. However, in the latter embodiment, a main actuator spring 36A is positioned between the top wall 18 of the upper housing 20 and a radial flange insert 90 which forms a part of the actuator 32. Also, the housing 14 is formed in two separate pieces comprising an intermediate housing 14A which is secured to the upper housing 20 by means of the bolts 92 and a lower housing 14B which is similarly secured to the housing portion 14A.
The actuator spring 36A normally forces the actuator 32 downwardly until a lower end is in stopped engagement with a shoulder 94 formed at the end wall of the housing 14A. A ball detent assembly with a plurality of balls 46 normally seated in recesses of a sleeve 42 act to interlock the actuator 32 and the valve stem 16 together during closing and a low value holding force is exerted on the poppet 10 when closed by means of an auxiliary holding spring 56. The spring 56 is positioned between a flange 58 of the actuator sleeve 42 and an upper end wall 96 of a tubular guide sleeve 98 which is restrained from upward movement by a retaining ring 100.
When it is desired to open the valve, pressurized fluid is introduced in the control chamber 28 through the port 54, and when the fluid pressure exerts a large enough force to overcome the force exerted on the spring 36A, the actuator 32 is moved upwardly until the balls 46 are seated in the recesses 102 provided in the sleeve 42. At this time, the actuator 32 becomes positively interlocked with the valve stem 16 and provides a high value plug unseating force which is capable of unseating and withdrawing the poppet 10 away from the seat 12. The actuator stem and valve 10 move farther upwardly after unseating until an upper end of the actuator 32 engages the top wall 18 of the housing 20. The actuator is continuously held in this position as long as the fluid pressure in the chamber 28 exceeds the force of the spring 36A.
When the valve 10 is to be closed, fluid in the chamber 28 is vented to atmosphere through the port 54 and when the fluid pressure in the chamber 28 is sufficiently low, the spring 36A then is able to force the actuator 32 and valve stem 16 combination downwardly so that the poppet 10 is positively seated on the seat 12.
The normally closed valve of FIG. 4 is provided with a spring 36A having a force sufficiently great to overcome the interlocking forces of the detent mechanism including the sleeve 42, balls 46 seated in the recesses 102 and biased by the springs 48'. As an example, if the valve 10 is to be closed or seated with a force ranging from sixty to eighty pounds, the actuator spring 36A must develop a force which exceeds this amount so that the detent mechanism will disconnect the actuator 32 from the valve stem 16 and permit the actuator 32 to move into stopping engagement with the shoulder 94. After this occurs a lower value holding force exerted by the spring 56 on the valve is sufficient to retain the valve closed in the seat 12 without causing excessive cold flow of the material of the valve poppet.
From the foregoing description it will be seen that in both the normally open and normally closed embodiments of the present invention, a high value and accurately repeatable seating or closing force is momentarily applied by the actuator to the valve poppet. This force value is determined by the detent mechanism including the sleeve 42, the balls 46 and spring 48 and insures positive insertion and progressive penetration of the poppet in the valve seat independently of a manually applied force, a spring biasing force, pneumatic or fluid pressure force or the rate of valve closure. After valve closure, the force acting to maintain the plug in a seated or closed condition is automatically dropped to a controlled moderate holding force that is less than the initial closing force but sufficient to positively retain the plug with ample sealing pressure against the seat to prevent fluid leakage. This seating or holding pressure is low enough to minimize any long term deformation or cold flow of the material of the plug, particularly if the material is a plastic resin such as "Teflon" brand material. For valve opening, the actuator provides a high value plug unseating or opening force to positively withdraw the plug and fully open the valve. In this connection it will be understood that while the present invention has been illustrated in connection with a frustoconically tapered plug type of poppet valve formed of "Teflon" resin, the actuator of the present invention may be used with other styles of poppets where a repeatable, high value initial closing force is desired followed by a reduced value and selectively controlled holding force for maintenance of the valve in a closed position for long term retention.
While the arrangement of the present invention is particularly adapted for control by pneumatic or hydraulic pressurized fluids, it will be appreciated that other forms of power may be employed to control movement of the valve stem. For example, the valve stem 16 may be directly actuated by an electrically operated solenoid or an electric motor, in which case the diaphragm 26 may be eliminated. Also, the valve stem 16 may be manually operated through any suitable type of direct acting linkage or mechanism, insofar as the present invention is concerned.
While there have been illustrated and described various embodiments of the present invention, it will be apparent that various changes and modifications thereof will occur to those skilled in the art. It is intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the present invention. | A poppet valve actuating apparatus includes an actuator for driving a valve poppet closed with substantial but momentary force to effect tight valve shutoff. After driving the poppet closed with a momentarily-applied relatively high-value force, the actuator then automatically reduces the poppet seating or holding force for maintaining the value in the closed position by automatic release of an integral detent coupling that applies a lower-value auxiliary spring holding force after the poppet is seated. The reduced value holding force prevents cold flow of the poppet material during extended periods wherein the poppet is in a closed position. | 5 |
RELATED APPLICATIONS
This is a continuation of U.S. patent application Ser. No. 11/607,763, filed Dec. 1, 2006, now U.S. Pat. No. 7,757,592 issued Jul. 20, 2010 and claims priority thereto.
TECHNICAL FIELD
The invention relates generally to woodworking and industrial power tools, and more particularly, to providing a cutting guide for a hand-held power saw.
BACKGROUND
Miter boxes are cutting guides that allow precision cuts using hand-held saws, because they both constrain the saw to move in a straight line and also align the cutting path with respect to the object being cut. Typical miter boxes are designed for hand-operated saws, and include cutting guides for 90-degree cross cuts, as well as 45-degree miter cuts. The cutting guides in a typical miter box are usually pairs of notches on opposing sides of the box, barely wider than the saw blade, and which are oriented at a precise angle with respect to the box's inner surfaces. These surfaces are a cutting surface, which the blade will score as it cuts through the object, and at least one other alignment surface, which may be identified as a fence. A miter box typically forms a 3-sided trough with a cutting surface at the bottom, and two fences protruding above the cutting surface. The notches are in the fences.
An object to be cut is placed on the cutting surface and held firmly against a fence. The saw blade is then placed in a set of notches, and the user may cut the object by sliding the saw blade back and forth within the notches. The notches work well for guiding hand-operated saws, because the blade spans the width of the miter box and is held in place by both notches. Further, the cutting edge of the blade only engages the object to be cut and the cutting surface. That is, the cutting edge of the blade does not contact the fences.
A typical miter box will not work with a common hand-held power saw, because the blade will not be held in place by both notches simultaneously when the cutting starts. Further, because the blade is circular, it will strike the distant fence and likely cut a new notch in it. For example, if an object to be cut is placed in a typical miter box, the power saw blade is set in one the notch of the first fence, and the saw is turned on, the single notch is unlikely to properly constrain the blade. As a result, as the user passes the saw through the object toward the second fence, the blade will likely engage the fence somewhere other than the pre-cut notch in the second fence. The cutting edge of the blade will then just cut a new notch in the second fence. The miter box will become damaged, and will not have achieved its purpose.
A common power tool for making precision cuts is a power miter saw. A power miter saw arrangement provides a cutting surface, typically a single fence, and a power saw attached to a precisely-oriented moving arm. The arm is allowed to move in an arc about a pivot point, and the angle of the arm motion is usually adjustable. A power miter saw allows precise cuts by guiding the blade via a calibrated arm attached to the motor and coupled to the fence.
Unfortunately, power miter saws may be expensive and heavy, and are often unsuited for some of the tasks for which a power saw is commonly used. Thus, a user may have two saws: a power saw for general cutting tasks and power miter saw for precision cuts. This duplication of power saws can be expensive and burdensome to transport to a job site.
BRIEF SUMMARY
Operating a power saw between a pair of parallel guide rails, which engage opposing sides of saw base plate to constrain the motion of the saw to a straight path, allows for precise cuts. A set of two or more fences allows for multiple cutting options. In some embodiments, two fences may engage opposing sides of the object to be cut simultaneously, holding the object more securely with respect to the guide rails than would a single fence. A possible clamping force holding the two fences against the object allows the miter guide to remain fixed relative to the object so that the user's hand may be freed for another task, such as holding the saw with both hands. The clamping force may result from one fence being adjustable, or the fences may be spaced apart to fit snugly over common sizes of pre-cut lumber.
In some embodiments, non-parallel fences coupled to the guide rails allow for precise cuts at more than just a single angle. One fence may be oriented at an angle between 59 degrees and 91 degrees with respect to the guide rails, and another fence may be oriented at an angle between 29 degrees and 61 degrees with respect to the guide rails. Because the fences are not parallel, they have a closest point on one side of the guide rails. The ends of the fences may be angled so that the end of each fence is parallel to the other fence at the closest point. Some embodiments do not require a cutting surface. That is, unlike a traditional miter box, in which the object to be cut is placed inside the box, embodiments of the invention may be placed on top of the object, with open space below the object.
The foregoing has outlined rather broadly the features and technical advantages of the present 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. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
FIG. 1 shows a prior art cutting guide;
FIG. 2 shows another prior art cutting guide;
FIG. 3A shows an embodiment of a power saw miter guide;
FIG. 3B shows another view of the power saw miter guide of FIG. 3A ;
FIG. 4A shows another embodiment of a power saw miter guide;
FIG. 4B shows another view of the power saw miter guide of FIG. 4A ;
FIG. 5 shows another embodiment of a power saw miter guide; and
FIG. 6 shows a method for using an embodiment of a power saw miter guide.
DETAILED DESCRIPTION
FIG. 1 shows prior art cutting guide 10 for making 90-degree cross cuts with power saw 101 . Prior art cutting guide comprises guide rail 103 and 104 , saw support surface 105 , parallel fences 107 and 108 , and cutting surface 109 . Saw support surface 105 comprises notch 106 through which saw blade 102 passes when cutting an object. Because notch 106 completely separates saw support surface 105 into two pieces, each of guide rails 103 and 104 must be firmly attached to both fences 107 and 108 for structural rigidity. As a result, in the prior art device 10 , fences 107 and 108 are not adjustable.
In operation, a user places an object to be cut on cutting surface 109 , between fences 107 and 105 , completely to the side of one of guide rails 104 and 103 . The object is then slid along cutting surface 109 until the part of the object to be cut is beneath notch 106 . Since the object must be able to slide along cutting surface 109 , and fences 107 and 108 are not adjustable, fences 107 and 108 cannot hold the object firmly. As a result, the user must use one hand to hold the object firmly against one of fences 107 or 108 while the object is being cut. This either requires the use of an assistant, or else leaves the user only a single hand for operating the saw.
FIG. 2 shows prior art cutting guide 20 for making cuts at an arbitrary angle. Cutting guide 20 comprises a single guide rail 201 attached to a single fence 202 , whereby guide rail 201 pivots about hinge 203 . Adjustable arc slot 204 works with hinge 203 to allow guide rail 201 to be oriented at a range of angles with respect to fence 202 . As with prior art cutting guide 10 from FIG. 1 , prior art cutting guide 20 only engages the object to be cut with a single fence, requiring that object be held against prior art cutting guide 20 . Further, since prior art cutting guide only has single guide rail 201 a saw may wander away from guide rail 201 , resulting in an imprecise cut.
FIG. 3A shows an embodiment of power saw miter guide 30 . Power saw miter guide 30 comprises first guide rail 303 , second guide rail 304 , first fence 307 and second fence 308 . Second guide rail 304 is oriented parallel to first guide rail 303 . First fence 307 is coupled to first guide rail 303 and second guide rail 304 and is oriented at an angle between 59 degrees and 91 degrees with respect to guide rails 304 and 304 . As shown in FIG. 3A , first fence 307 is oriented at an angle of approximately 90 degrees with respect to guide rails 304 and 304 . Second fence 308 is also coupled to first guide rail 303 and second guide rail 304 and is oriented at an angle between 29 degrees and 61 degrees with respect to guide rails 304 and 304 . As shown in the figure second fence 308 is oriented at an angle of approximately 45 degrees with respect to guide rails 304 and 304 .
Guide rails 303 and 304 constrain motion of saw 101 to a straight path by engaging opposing sides of the base plate of saw 101 as saw 101 rides on saw support surface 305 . Saw blade 102 passes through notch 306 to cut an object that may be set on cutting surface 309 , and aligned against either fence 307 or fence 308 . Window 302 in saw support surface 305 between guide rails 303 and 304 allows a user to see that the object being cut is aligned properly within miter guide 30 between fences 307 and 308 . Window 302 does not span the entire distance between guide rails 303 and 304 , so that a portion of saw support surface 305 is still available to support saw 101 .
The arrangement of guide rails 303 and 304 , fences 307 and 308 with respect to saw support surface 305 and cutting surface 309 can be seen in FIG. 3A . Saw support surface 305 and cutting surface 309 are parallel. Fences 307 and 308 are on top of cutting surface 309 , and saw support surface 305 is on top of fences 307 and 308 . Guide rails 303 and 304 are the above saw support surface 305 . Fences 307 and 308 are thus coupled to guide rails 303 and 304 through saw support surface 305 . Optional carrying handle 301 in cutting surface 309 makes miter guide 30 conveniently transportable. Alternatively, optional carrying handle 301 could be placed at any convenient location on miter guide 30 .
Since fences 307 and 308 are not parallel, there is a point at which they would intersect, if they were not truncated. This arrangement could limit the length of the object to be cut, or at least limit the length that could be cut from it. As a result, unlike fences 107 and 108 of prior art cutting guide 10 from FIG. 1 , fences 307 and 308 of miter guide 30 must be truncated shortly outside of guide rails 303 and 304 . Fences 307 and 308 reach a closest point just outside guide rail 303 . In this area, end 310 of fence 307 is parallel to fence 308 , while end 311 of fence 308 is parallel to fence 307 . With proper spacing, ends 310 and 311 of fences 307 and 308 , respectively, could provide an extra alignment point for common sized pre-cut lumber.
For example, if the distance between ends 310 and 311 may be set so that if one side of a 2×4 piece of lumber is pressed against fence 307 , the opposing side of the 2×4 could contacts end 311 . Alternatively, a 2×4 pressed against 308 may also contact end 310 . This arrangement will provide added stability for the object to be cut. Typical dimensions for miter guide 30 to accommodate commonly available power saws would be: the distance between guide rails 303 and 304 set between 5 inches and 7 inches, the distance between saw support surface 305 and cutting surface 309 set between 1 inch and 5 inches, and notch 306 set between 1 and 3 inches in depth.
Other dimensions may be used without departing from the spirit and scope of the invention. Further, if cutting surface 309 was eliminated, miter guide 30 would be placed on top of the object to be cut, rather than the object to be cut being placed inside miter guide 30 . That is, the underside of saw support surface 305 or guide rails 303 and 304 would rest on top of the object to be cut. Fences 307 and 308 must then be taller than the depth of notch 306 at the point where notch 306 passes through fences 307 and 308 .
FIG. 3B shows another view of power saw miter guide 30 , but without saw 101 . The extent of window 302 between guides 303 and 304 and fences 307 and 308 is more easily seen in FIG. 3B , as well as the location where notch 306 intersects fence 308 . Note that miter guide 30 allows precision cuts at two different angles, which is not possible with prior art cutting guide 10 , and holds both sides of saw 101 , whereas prior art cutting guide 20 cannot.
FIG. 4A shows another embodiment of the invention as reflected in power saw miter guide 40 . Miter guide 40 comprises guide rails 403 and 404 , along with fences 407 and 408 . Saw support surface 405 is the top surfaces of fences 407 and 408 . Since there is no cutting surface, fences 407 and 408 are taller than the depth of notch 406 , and notch 406 is separated into two parts. End 410 of fence 407 is parallel to fence 408 , while end 411 of fence 408 is parallel to fence 407 . Miter guide 40 is used by setting miter guide 40 atop the object to be cut, rather than setting the object to be cut on a cutting surface. As can be seen from FIGS. 4A and 4B , top surfaces 405 of fences 407 and 408 are parallel and lie in a common plane with the undersides of guide rails 403 and 404 .
Miter guide 40 also has two additional fences 412 and 413 , both of which are visible in FIG. 4B . Fence 412 is parallel to fence 407 , while fence 413 is parallel to fence 408 . With proper spacing between pairs of fences 407 and 412 or 408 and 413 , commonly-sized pre-cut lumber may be held firmly with respect to miter guide 40 . That is, fences 407 and 412 may be set apart such that miter guide 40 fits snugly over a 2×4. Additionally, the spacing of fences 408 and 413 may be set to accommodate a common size of lumber. Typical dimensions for miter guide 40 may be a distance between fences 407 and 412 or 408 and 413 of between 1 inch and 5 inches.
FIG. 5 shows yet another embodiment of the invention as reflected in power saw miter guide 50 . Miter guide 50 comprises guide rails 503 and 504 , along with fences 507 and 508 . Saw support surface 505 is the top surfaces of fences 407 and 408 , along with some extensions added to improve the rigidity of miter guide 50 at the intersections of guide rail 503 with fences 507 and 508 . Fences 507 and 508 are taller than the depth of notch 506 . Ends 510 and 511 of fences 507 and 508 , respectively, are parallel with the opposing fence, 508 and 507 , respectively.
Fences 512 and 513 are two sides of adjustable fence assembly 514 , where fence 512 is parallel to fence 507 and fence 513 is parallel to fence 508 . Adjustable fence assembly 514 has two slots 515 and 516 . Adjustment bolts 517 and 518 in guide rail 504 pass through slots 515 and 516 , so that adjustable fence assembly 514 rides along an angled path with respect to both fences 507 and 508 . For example, if fences 507 and 508 form a 45-degree angle, then fences 512 and 513 also form a 45 degree angle. Slots 515 and 516 then could be at a 22.5-degree angle with respect to both fences 507 and 507 . This way, as adjustable fence assembly 514 moves inward, toward the closest point between fences 507 and 508 , the distance between fences 507 and 512 closes. The distance between fences 513 and 508 will also close as adjustable fence assembly 514 moves inward. Conversely, as adjustable fence assembly 514 moves outward, away from the closest point between fences 507 and 508 , the distances between fences 507 and 512 or 508 and 513 will increase.
In operation, miter guide 50 may be set on top of an object to be cut, and aligned using either fence 507 or 508 . Adjustable fence assembly 514 is then moved so that the object is held between either fences 507 and 512 or fences 508 and 513 . Adjustment bolts 517 and 518 may then be tightened so that miter guide 50 is held firmly relative to the object. Spring loaded or other flexible tension methods may alternatively be used, rather than bolts, in order to provide holding force for adjustable fence assembly 514 .
FIG. 6 shows method 600 for using an embodiment of a power saw miter guide. In process 601 , an object to be cut is aligned against a first fence. In process 602 , a second fence, parallel to the first fence, is brought against the opposing side of the object. If the distance between the parallel fences is not adjustable, but is rather set to be snug against opposing sides of commonly-sized pre-cut lumber, process 602 may be nearly simultaneous with process 601 . In process 603 , a saw base plate is set between parallel guide rails. In process 604 , the saw is operated between two parallel guide rails. The guide rails engage opposite sides of the base plate to constrain motion of the saw to a straight path.
Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. | Operating a power saw between a pair of parallel guide rails, which engage opposing sides of saw base plate to constrain the motion of the saw to a straight path, allows for precise cuts. A set of two or more fences allows for multiple cutting options. In some embodiments, non-parallel fences coupled to the guide rails allow for precise cuts at more than just a single angle. In some embodiments, two fences may engage opposing sides of the object to be cut simultaneously, holding the object more securely with respect to the guide rails than would a single fence. A possible clamping force holding the two fences against the object allows the miter guide to remain fixed relative to the object so that the user's hand may be freed for another task, such as holding the saw with both hands. | 1 |
BACKGROUND OF THE INVENTION
The present invention generally involves well logging instruments, and more specifically discloses embodiments directed to combination instruments which perform such functions as measuring formation density and wellbore diameter in addition to running radioactive logs such as a neutron log.
Previous tool designs accomplished these functions using an elongated body having a widely extendable decentralizer arm and drag pad, which arm also comprised part of the caliper instrument. On the back side of the body was the heavy density pad which preferably was kept close to the tool body for accuracy of the logging function. It was preferable to make this pad slightly extendable from the body, for instance one-fourth to three-fourths of an inch extension.
In one type of prior art device, this slight extension of the so-called "fixed pad" containing the logging signal transmitter and receiver, was achieved prior to lowering the tool into the well, and the fixed pad was actually pinned into place in its extended position. Thus, the pad became known as the fixed pad because it remained in the extended position at all times when in the wellbore.
The disadvantage in the fixed pad design is that it undergoes considerable wear and deterioation moving up and down the borehole at speeds of up to 500 feet per minute. This would also shake and dislodge the electrical components in the pad, causing malfunction there.
One solution to the problem has been to incorporate a complex hydraulic-mechanical system into the tool to provide for extension of the density pad at a selective position in the borehole. Examples of this are found in U.S. Pat. Nos. 3,356,146 and 3,254,221. This complex hydro-mechanical system requires extensive modification of the tool configuration to incorporate the needed pad extension components. In addition, the density pad extension is accompanied by extension of a hydraulic cylinder into the wellbore, and control of the amount of extension is lacking at the top of the assembly.
The present invention overcomes these disadvantages by providing a mechanical linkage assembly which is not overly complex yet which provides a predetermined extension of the density pad at the desired time in the wellbore. The invention does not require extension modification of the tool configuration to achieve the desired pad extension.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1a-1d, when joined at common lines a-a, b-b and c-c form FIG. 1 which comprises a schematic cross-sectional view of one embodiment of the invention.
FIGS. 2, 3, and 4 illustrate different views of a portion of the linkage of the first embodiment.
FIGS. 5a-5d, when joined at common lines a-a, b-b and c-c form FIG. 5 which illustrates a second embodiment of the invention.
FIGS. 6-9 illustrate cross-sectional axial views of the second embodiment taken at lines 6--6 through 9--9 in FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a schematic cross-sectional illustration of one embodiment of the logging tool 10. The tool 10 comprises a generally cylindrical elongated body member 11 in which is located a collapsible linkage assembly 12. A widely extendable caliper arm 13 is pivotally connected to the body at pin 14 and has at its outermost end a contact pad 15.
Caliper arm 13 is arranged to be folded into a receptacle opening 16 cut through the wall of body 11. Caliper arm 13 has a bellcrank arm 17 extending past pivot pin 14 and pivotally connected by pin 18 to a slide arm 19. Arm 19 is pivotally connected by pin 20 to a sliding block 21 located slidably in body 11.
Sliding block 21 has a follower channel 22 formed therein which contains a sliding pin 23 captively held therein. Rotatably connected to pin 23 is a bellcrank arm 24 pivotally connected at 25 to body 11. Arm 24 extends downward past pin 25 in an angular section 26 and an extended vertical section 27. The lower end of extended arm section 27 is pivotally connected at 28 to the back shoulder 29 of a density logging pad 30.
Pad 30 contains various logging signal transmitters and receivers such as radioactive logging elements. A bottom cap 31 is connected to density pad 30 and contains a guide opening 32 formed therein into which projects a limit peg 33 for limiting outward extension of pad 30.
Sliding block 21 is securely connected to an actuator plunger 34 which is abutted by a compression spring 35. A stationary collar 36 is in abutment with the upper end of coil spring 35 and is secured within body 11 against vertical movement. A pair of side bar links (not shown) connect a drive motor (not shown) to crosspin 39a which is securely engaged in the intermediate plunger shaft 39. Shaft 38 extends concentrically inside of spring 35, collar 36 and sleeve 37 and is threadedly connected to intermediate shaft 39, which in turn is attached to a potentiometer shaft 40.
Referring now to FIGS. 2 and 3, an enlarged view of the sliding block 21 and actuator plunger 34 is shown. In FIG. 3 the follower channel 22 is more clearly seen. Channel 22 consists of an elongated vertical section 22a and an angular down-turned section 22b at one end. The engagement of pin 23 is in the lowermost end of section 22b when the tool is completely collapsed and ready for free sliding movement downhole.
In typical operation, the logging tool 11 is placed on the wireline with the other logging tools in its collapsed position as illustrated in FIG. 1. The tools are lowered into the borehole to the formation to be logged. The tool is then actuated by means of the electric motor which applies a downward movement to shafts 38, 39, and 40 through side links (not shown).
The downward movement releases coil spring 38 against actuator plunger 34 thereby moving plunger 34 and slide block 21 downward in the tool. Downward movement of slide block 21 reacts through slide arm 19 to apply an opening force on bellcrank arm 17 thereby pivoting caliper arm 13 outward until pad 15 engages the borehole wall. This engagement of pad 15 against the borehole serves to decentralize tool 11, pushing it across the borehole against the opposite wall. Upon the initial downward movement of slide block 21, pin 23 on bellcrack arm 24 will be forced through section 22b into section 22a of the follower channel 22. This slight angular movement from section 22b applies a very slight rotational moment to bellcrank arm 24 which is transferred through pin 25 to angular section 26 and vertical arm 27.
The multiplication of this rotation of 24 throughout the length of 27 results in a predetermined radial outward movement of density pad 30 by means of pin 28 on the rear shoulder 29 of the density pad. Thus upon initial expansion of caliper arm 13 to contact the borehole wall and force the logging pad 30 against the opposing wall, a slight initial extension of pad 30 will be achieved simultaneous with the opening of caliper arm 13. This preselected extension of density pad 13 is sufficient to provide the optimum logging accuracy of the radioactive instruments located in the large pad.
Referring now to FIGS. 5-9, a second embodiment of the invention is illustrated utilizing a density pad and caliper arm arrangement. In FIG. 5, the logging tool 100 is illustrated in cross-sectional schematic view having an elongated generally cylindrical body 101 in which is located a central shaft 102 connected to potentiometer 105. A pair of coil springs 104 are held in compression by a spring plate 103 around shaft 102. A lower spring plate assembly 106 receives the lower end of springs 104.
Shaft 102 is connected to a plunger rod 107 which extends downwardly into connection with a traveling block 108. A pair of side bar drive links connect the drive motor in the upper portion of the tool with plunger rod 107 by means of a transverse drive pin 109. Side bar links 110, although not shown in FIG. 5 are illustrated in FIG. 9.
A slide bracket 111 is connected to traveling block 108 and contains a follower window 112 formed therein. A circular roller 113 is located in relatively close fitting relationship in window 112. A drive arm 114 is pinned at 115 to the center of roller 113 and is rotatably pinned to the tool body by pin 116. Drive arm 114 has a lower vertical section 117 extending downward generally parallel to and recessed within body 101. An articulated pad arm 118 is pinned to arm section 117 by a pivotal connection 119 in an opening 120 cut through the center portion of section 117. The lower portion of opening 120 is formed in the tapered abutment surface 121 arranged to abut articulated arm pad 118 and rotated outward against the borehole wall. A contact pad 122 is pivotally connected to arm 118 and lower section 117.
A second follower channel 123 is formed in slide bracket 111 and has at one end (not shown) an angular short section similar to the one disclosed in FIG. 3 at 22b. A follower pin 124 is located in close fitting slidable relationship in channel 123 and has retained thereon a bellcrank arm 125 which is rotatably pinned to the body at 126. The bellcrank arm has a second angular section 127 and a generally vertical lower section 128 upon which is rotatably pinned the logging pad 130 at pin 129.
A third follower channel 131 is formed in bracket 111 and receives a stationary guide pin 132 securedly held in the tool body and projecting inward through channel 131 to maintain guide bracket 11 in proper lateral alignment.
In typical operation, the logging instrument 100 is lowered by wireline into the wellbore until it reaches the area of the underground formation to be logged. The electric motor is actuated which applies a downward movement of link bars 110 to release compression springs 104. This applies a downward force to rod 107 which transfers through bracket 111 to roller 113. This applies a rotational moment to drive arm 114 moving linkage 117 and 118 radially outward from the tool body until pad 122 engages the borehole wall thereby decentralizing the tool body against the opposing borehole wall.
Simultaneously, with the opening of the caliper arm 118 and pad 122, bracket 111 moves downward, forcing pin 124 out of the angular end of channel 123 and applying a rotational force to arm 125 which is transferred via arm sections 127 and 128 to the logging pad 130. The slight rotation of arm 125 about pin 126 moves the density pad 130 outward a preselected distance into engagement with the formation to be logged.
Thus, it can be seen that the embodiments of the present invention provide a very dependable and efficient but not overly complex apparatus for a logging tool which maintains the caliper pad and logging pad inside the tool body until the moment that logging operations are to begin. The apparatus removes the need for complex hydro-mechanical assemblies and provides sufficient radial extension of the logging pad to make optimum contact with the borehole wall and yet maintains a logging pad close enough to the tool to maintain maximum accuracy and minimum deterioration of the logging instrument. Furthermore, the tool combines the caliper function of the widely extendable caliper arm with the logging function of the slightly extendable density pad.
Although a specific preferred embodiment of the present invention has been described in the detailed description above, the description is not intended to limit the invention to the particular forms of embodiments disclosed therein since they are to be recognized as illustrative rather than restrictive and it will be obvious to those skilled in the art that the invention is not so limited. For instance, whereas the present invention is described for use as a density measuring instrument, it is obvious that other type logging tools which are required to be maintained close to the borehole wall could be utilized effectively instead of or in conjunction with the density instrument. For example, one type of instrument used in conjunction with the density logging tool is the compensated neutron well logging system. Thus, the invention is declared to cover all changes and modifications of the specific example of the invention herein disclosed for purposes of illustration which do not constitute departures from the spirit and scope of the invention. | A wellbore logging instrument is disclosed of the type having a density pad maintained in close proximity to the tool body, and a decentralizing arm pivotally mounted on the body and arranged to swing outward against the borehole to move the tool body and density pad against the opposite borehole wall. The apparatus includes a linkage assembly to provide a slight extension of the density pad at any selected time in the borehole. | 4 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to farm implements and, more particularly, to a seed metering cassette for a seeding implement, such as an air seeder.
[0002] Air seeders are commonly towed by tractors to apply seed, fertilizer, or micro-nutrients or any granular product to a field. For purposes of this application “seeding” shall include the application or deposition of any granular or particulate material onto a field, and “seed” shall include seed, fertilizer, micronutrients, or any other granular material that may be applied onto a planting surface, farm field, seedbed, and the like. It is generally advantageous to tow an air seeder in combination with a tilling implement, one behind the other, to place the seed and fertilizer under the surface of the soil. An air seeder has as its central component a wheeled seed cart which comprises one or more frame-mounted seed tanks for holding product, generally seed or fertilizer or both. Air seeders also generally include a volumetric metering system operable to measure a fixed volume of seed per unit of linear distance and a pneumatic distribution system for delivering the product from the tank to the soil.
[0003] The volumetric metering system is configured for distribution of product from the tank to the distribution headers of the seed tubes. The metering system typically includes a meter roller assembly employing augers or fluted cylinders (meter rollers) situated in a meter box assembly secured below the tank.
[0004] Typically the meter box will have a series of outlets known as runs that each leads to the distribution lines of the pneumatic distribution system. The pneumatic distribution system generally includes an air stream operable to carry product metered by the meter roller assembly through the distribution lines to a series of secondary distribution manifolds (“headers”), which in turn distribute product to a group of ground openers mounted on the seeding implement operable to place seed in the ground. The ground openers are configured to evenly deliver the product to the span of ground (the “seedbed”) acted upon by the seeding implement.
[0005] To reduce manufacturing costs and eliminate consumer confusion is customizing an air seeder, most manufacturers offer a seed metering assembly in which the meter box and the fluted meter roller that are sized to meter granular material to a preset number of secondary headers. One of the drawbacks of such a construction is that not all implements require or have the preset number of secondary headers. For those implements having fewer secondary headers, sections of the seed metering assembly must be capped off. The result is that the consumer is required to purchase a seed metering assembly that may be larger than the consumer requires.
[0006] Additionally, for some implements, there can be some inconsistency in the number of outlets of the secondary headers. This inconsistency is generally the result of the implement having a particular frame configuration that may be required to achieve a particular transport configuration. Since the meter roller meters granular material to each of the secondary headers at the same metering rate, the amount of granular material per outlet will be higher for those secondary headers having a fewer number of outlets. As a result, the seedbed serviced by the ground opener units that are fed by the headers having fewer outlets will be over-seeded compared to the seedbed serviced by the other ground opener units. This discrepancy in the application of granular material, which heretofore has been generally ignored, can ultimately lead to inconsistent seeding and thus inconsistent per row crop yields.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to a modular seed metering assembly or unit in which several such modular units can be used to build a seed metering apparatus that is matched to a particular implement. Each modular assembly is a stand-alone unit that can be controlled to meter granular material at a metering speed that is independent of the metering speed of the other units of the seed metering apparatus. Each seed metering unit is selectively driven by a common drive member, such as a drive shaft. Thus, when a seed metering unit is engaged with the drive member, the unit will meter granular material. On the other hand, when the seed metering unit is not engaged with the drive member, the metering unit will not meter granular material. Hence, the present invention also provides a seed metering apparatus that provides effective sectional control. Moreover, when an engaged seed metering unit is disengaged, the response time is nearly instantaneous. Thus, metering by the disengaged seed metering unit ceases nearly immediately.
[0008] Accordingly, in one aspect of the invention, a seed metering apparatus is provided that is capable of metering measured amounts of granular material to a number of secondary headers using a series of modular seed metering units that can be independently controlled to provide sectional control during seeding.
[0009] In a further aspect, each metering unit can be caused to run faster or slower than other metering units of the metering apparatus to provide additional control in the metering of seed, fertilizer or other granular material.
[0010] In accordance with another aspect of the invention, a modular seed metering unit or seed metering cassette is provided that allows a seed metering unit to be added or removed from a seed metering apparatus as a stand-alone component. In this regard, the needed number of seed metering units for a given air seeder can be achieved by stacking together modular units. As such, the present invention allows an air seeder to be built using modular components rather than using a single, fixed length meter roller.
[0011] It is therefore an object of the invention to provide a seed metering apparatus with sectional control and, more particularly, sectional control with a quick response time.
[0012] It is another object of the invention to provide a cassette-based seed metering unit in which multiple such units could be arranged together to form a seed metering apparatus.
[0013] Other objects, features, aspects, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.
BRIEF DESCRIPTION OF THE FIGURES
[0014] Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout.
[0015] In the drawings:
[0016] FIG. 1 is an isometric view of a seed metering apparatus for use with an air seeder according to one embodiment of the present invention;
[0017] FIG. 2 is a side elevation view of the seed metering apparatus of FIG. 1 ;
[0018] FIG. 3 is a rear view of one seed metering unit of the seed metering apparatus of FIG. 1 ; and
[0019] FIGS. 4-5 are views of a bulk fill hopper of the seed metering apparatus of FIG. 1 according to another aspect of the invention.
DETAILED DESCRIPTION
[0020] Turning now to FIG. 1 , a seed metering apparatus 10 for an air seeder (not shown) includes a series of seed metering units 12 each mounted to a seeder frame 14 , e.g., frame crossbar 14 a , adjacently below a hopper 16 . In one embodiment, the frame 14 includes the aforementioned crossbar 14 a and an upland crossbar 14 b that are interconnected between a pair of parallel rails 15 . Each seed metering unit 12 is designed to meter granular material, e.g., seed or fertilizer, from the hopper 16 to one or more delivery conduits 18 . The hopper 16 is mounted to the parallel rails 15 in a conventional manner, i.e., by mounts 17 . It will thus be appreciated that the seed metering units 12 are supported at one end by a connection to crossbar 14 a and supported at an opposite end by hopper 16 .
[0021] As will be described more fully below, each seed metering unit 12 is a self-contained, modular, and individual assembly. In this regard, the number of seed metering units for a given seed metering apparatus may vary from that shown in figures. Moreover, the modularity of the seed metering units 12 allows the number of seed metering units to be matched to the number of secondary headers (not shown) of the air seeder. Further, the present invention allows seed metering units to be added to a given air seeder as needed. Additionally, as will be described, each metering unit can be independently controlled. Thus, each metering unit can meter granular material at a speed that is independent of the meter rates of other metering units. This is particularly advantageous for air seeders having secondary headers with differing number of outlets.
[0022] With additional reference to FIGS. 2 and 3 , each metering unit 12 has a bulkhead 20 that defines a cavity 22 containing a meter roller assembly 24 . The meter roller assembly 24 includes a fluted rotor 26 that is rotatably mounted to bulkhead 20 by a bearing assembly 28 , which includes a bearing 30 . O-rings 31 provide sealing of the rotor 26 in the bulkhead 20 . As known in the art, when the rotor 26 rotates, the fluted rotor 26 captures granular material as it falls from the hopper 16 and passes the captured granular material to the delivery conduits associated with the seed metering unit 12 .
[0023] Each fluted rotor 26 further has a pulley 32 that is mounted to, or integrally formed with, the rotor 26 . In the illustrated example, an end of the rotor 26 passes through an opening 33 formed in the bulkhead. The pulley 32 is attached to the exposed portion of the rotor 26 . Each pulley 32 is caused to rotate by a drive belt 34 that is entrained about the pulley 32 and a drive shaft 36 . As shown particularly in FIG. 1 , a series of pulleys 37 are mounted to the drive shaft 36 and thus rotate with rotation of the drive shaft 36 . Each drive belt is each entrained about a respective pulley 32 and a respective drive pulley 37 . In this regard, a single and common drive shaft 36 is used to cause rotation of the fluted rotors 26 . In a preferred embodiment, drive belts 34 are each V-belts, but it is understood that other types of elongated members could be used, such as chains, links, cable, and the like.
[0024] When drive shaft 36 rotates, the drive belts 34 are caused to translate around the drive shaft and their respective pulleys 32 to cause rotation of the fluted rotor 26 and ultimately metering of granular material passed from the hopper 16 to the seed metering unit 12 . The present invention, however, provides sectional control of the seeding process. In this regard, each metering unit 12 also includes an idler roller 38 that is mounted to a bell crank 40 . The bell cranks 40 are pivotably mounted to the seeder frame 14 in a conventional manner. In addition to being entrained about pulley 32 and drive shaft 36 , each drive belt 34 is also entrained about a respective idler roller or pulley 38 . Each idler roller 38 is designed to add or remove tension to its associated drive belt 34 . When the drive belt 34 is tensioned, rotation of the drive shaft 36 will cause translation of the drive belt 34 and thus rotation of the pulley 32 . On the other hand, when there is sufficient slack in the drive belt, the drive belt 34 will be loosely entrained about the drive shaft 36 and, as a result, rotation of the drive shaft 36 will not cause translation of the drive belt 34 . Accordingly, when there is sufficient slack in the drive belt 34 , rotation of the drive shaft 36 will not cause rotation of the fluted rotor 26 . It will thus be appreciated that sectional control can be achieved by selectively disengaging a selected seed metering unit from tensioned engagement with the drive shaft 36 .
[0025] Movement of the idler roller 38 is controlled by a respective bell crank 40 . In this regard, the bell crank 40 is movable between an engaged position and a disengaged position. A tensioning spring 42 is interconnected with the seeder frame 14 , e.g., crossbar 14 b , and the bell crank 40 to bias the bell crank 40 , and thus the drive belt 34 , in the engaged position. In a preferred embodiment, each bell crank 40 is linked to a drive input (not shown) that is operative to move the bell crank 40 between the engaged and disengaged positions. The drive input may be any known or to be developed input device. For example, a hydraulic, pneumatic, mechanical, or electrical circuit could be used to move the bell crank 40 between the engaged and disengaged positions. Moreover, it is contemplated that each input device may be controlled via an operator input or controlled automatically, such as by a GPS-based control.
[0026] In one preferred embodiment, a single input device is used to simultaneously move a set of bell cranks 40 to effectuate engagement/disengagement of a set of seed metering units 12 . This “tying” of multiple seed metering units 12 to a single input device allows all of the seed metering units 12 feeding granular material to a given secondary header to be started or stopped at the same time. While the seed metering units can be grouped together and thus controlled by a shared input device, the present invention is not so limited. Each seed metering unit, or a given group of seed metering units, can be selectively disengaged from the common drive shaft to effectively stop the metering by the selected seed metering units. It will thus be appreciated that the invention provides sectional control without mechanical gates or similar devices.
[0027] Additionally, the modularity of the seed metering units and the independent coupling of each seed metering unit to the drive shaft effectively provides a cartridge or cassette that can be added on an as-needed basis to a given air seeder. Moreover, because each seed metering unit is a separate stand-alone cartridge, metering units will different characteristics can be used on a single air seeder. For example, a larger pulley 32 could be used for one seed metering unit to provide metering at a slower rate and a smaller pulley 32 could be used for another seed metering unit to provide metering at a faster rate. This modularity could be particularly advantageous in instances in which it is desirable to meter seed and fertilizer at different rates.
[0028] Referring briefly again to FIG. 2 , the bulkhead 20 , in one preferred embodiment, has a pair of service openings. One service opening is a drain port 44 that is formed in the lower end of the bulkhead 20 . The drain port 44 , when opened, allows granular material to be drained from the hopper. The drain port 44 is selectively opened and closed by a drain door or panel 46 that is pivotably mounted to the hopper 16 by linkage 48 .
[0029] Generally opposite the drain port 44 is an access opening 50 . The access opening 50 is sized to allow removal of the rotor 26 when disconnected from the rotor bearing assembly 28 . The access opening 50 is opened and closed by an access panel 52 that is pivotably mounted to a lower end of the bulkhead 20 by linkage 54 .
[0030] Referring now to FIGS. 4-5 , hopper 16 has an internal volume 56 defined by a front panel 58 , rear panel 60 , and side panels 62 , 64 . The hopper 16 further has a lower panel 66 . The panels are interconnected in a known manner or could be integrally formed as a single unit. In one preferred embodiment, the lower panel 66 includes a series of openings 68 . The number of openings 68 is matched to the number of seed metering units 12 . It will thus be appreciated that the invention provides a hopper 16 that can be quickly serviced to provide a number of discharge openings matched to the number of seed metering units. In one embodiment, each opening 68 can be closed as needed by a cover plate 70 which is secured to the lower panel 66 using conventional fasteners, such as wing nuts 72 . Alternately, it is contemplated that the lower panel has linearly spaced knockouts. When a knockout is removed, a corresponding opening in the lower panel is exposed. In one embodiment, the knockouts cannot be reattached to the lower panel; although, other embodiments may have re-attachable knockouts. Additionally, it is contemplated that other types of devices may be used to selectively form discharge openings in the lower panel, such as slidable or removable doors, louvers, and the like.
[0031] While a drive belt and pulley arrangement is shown in the figures and has been described above, it is understood that other types of arrangements could be used, such as gears, clutches, individual electric motors or hydraulic motors, and the like.
[0032] From the foregoing it will be appreciated that the present invention provides a seed metering apparatus capable of metering measured amounts of granular material to a number of secondary headers using a series of modular seed metering units that can be independently controlled to provide sectional control during seeding. Each metering unit can be caused to run faster or slower than other metering units of the metering apparatus. Moreover, the modularity of the present invention allows each seed metering unit to be added or removed from the seed metering apparatus as a stand-along cartridge or cassette. It will also be appreciated that the present invention provides sectional control with a quickened response time. When the drive belt for a given seed metering unit is loosened as a result of its bell crank being moved to the disengaged position, the meter roller for the seed metering unit will stop nearly instantaneously. As such, the present invention avoids the shut-off lag times typically associated with sectional control.
[0033] Many changes and modifications could be made to the invention without departing from the spirit thereof. The scope of these changes will become apparent from the appended claims. | The present invention is directed to a seed metering assembly comprised of a set of stand-alone modular seed metering units. Each seed metering unit is selectively driven by a common drive member, such as a drive shaft. When a seed metering unit is engaged with the drive member, the unit will meter granular material. On the other hand, when the seed metering unit is not engaged with the drive member, the metering unit will not meter granular material. Hence, the present invention provides a seed metering apparatus in which the number of seed metering units can be scaled to match the number of distribution headers of a seeding implement. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an operation input device which is applicable to a portable telephone or a portable music player.
2. Description of the Related Art
Heretofore, an operation input device for use in a portable telephone or the like has been, for example, one including a base, a printed circuit board which has a plurality of pushbutton switches and magnetic field detecting elements mounted on its upside and which is stacked on and united with the base, an operation plate which is placed on the printed circuit board, and a disc type operation dial in which an annular magnet with N-poles and S-poles arranged alternately is assembled on the underside of the operation dial and which is turnably assembled on the operation plate. With the operation input device, the operation dial is turned, whereby the changes of the magnetic fluxes of the annular magnet are sensed by the magnetic field detecting elements so as to detect a turning direction, while the operation dial is depressed, whereby the pushbutton switch is operated (refer to JP-A-2003-280799).
The operation input device is schematically shown in FIG. 19 . As seen from the figure, the peripheral edge of a rotary member (operation dial) 154 is retained through a retaining ring 164 which is mounted on a base 120 . Here, the rotary member (operation dial) 154 is subjected to a turning operation and a depressing operation, thereby to drive any of pushbutton switches not shown. In this case, when the upper peripheral edge of the rotary member 154 abuts against the retaining ring 164 in depressing the peripheral edge of this rotary member 154 , an operation feeling worsens, and hence, some gap G 1 is provided. Due to the provision of the gap G 1 , however, the rotary member 154 becomes rickety in a vertical direction. It is therefore considered to urge the rotary member 154 upwards by elastic members. With such a configuration, however, the retaining ring 164 and the upper peripheral edge of the rotary member 154 come into touch, and a friction develops in subjecting the rotary member 154 to the turning operation. This leads to the problem that a smooth turning operation is not attained.
SUMMARY OF THE INVENTION
In view of the problem mentioned above, the present invention has for its object to provide an operation input device of good operation feeling, which removes the vertical ricketiness of an operation dial and ensures a smooth turning operation.
In order to accomplish the object, an operation input device according to the invention consists in comprising a base, a printed circuit board which has a plurality of pushbutton switches and magnetic field detecting elements mounted on its upside and which is stacked on and united with the base, an operation plate which is supported on the base so as to be vertically movable on the printed circuit board, and a disc type operation dial in which an annular magnet with N-poles and S-poles arranged alternately is assembled on an underside of the operation dial and which is turnably assembled on an upside of the operation plate; wherein the disc type operation dial is turned, thereby to sense changes of magnetic fluxes of the annular magnet by the magnetic field detecting elements and to detect a turning direction, while the disc type operation dial is depressed, thereby to operate any of the pushbutton switches through the operation plate.
In the invention, a depressing operation function is allotted to the operation plate which is supported on the base so as to be vertically movable, while a turning operation function is allotted to the operation dial which is turnably assembled on the upside of the operation plate. Therefore, the vertical ricketiness can be eliminated, and a smooth turning operation is permitted, so that the operation input device of good operation feeling is obtained.
As an embodiment according to the invention, the outer peripheral edge parts of a slide sheet which is arranged between the operation plate and the disc type operation dial are supported by the base, thereby to bestow urging forces on the operation plate.
According to this embodiment, the slide sheet urges the operation plate downwards, so that the vertical ricketiness of the operation plate can be prevented more reliably, and the operation feeling is enhanced.
In the invention, an operation input device may well comprise a base, a printed circuit board which has a plurality of pushbutton switches and magnetic field detecting elements mounted on its upside and which is stacked on and united with the base, an operation plate which is arranged on the printed circuit board, a disc type operation dial in which an annular magnet with N-poles and S-poles arranged alternately is assembled on an underside of the operation dial and which is turnably assembled on an upside of the operation plate, and a flexible slide sheet which is arranged between the operation plate and the disc type operation dial and whose outer peripheral edge parts are supported by the base; wherein the disc type operation dial is turned, thereby to sense changes of magnetic fluxes of the annular magnet by the magnetic field detecting elements and to detect a turning direction, while the disc type operation dial is depressed, thereby to operate any of the pushbutton switches through the operation plate.
According to the invention, the operation plate is supported through the flexible slide sheet supported on the base. Here, a depressing operation function is allotted to the slide sheet and the operation plate, while a turning operation function is allotted to the operation dial which is turnably assembled on the upside of the operation plate. Therefore, the vertical ricketiness can be eliminated, and a smooth turning operation is permitted, so that the operation input device of good operation feeling is obtained.
As an embodiment according to the invention, the operation plate may well have its underside pushed up by elastic arms cut and raised from the base, thereby to be urged upwards.
According to this embodiment, the operation plate is pushed upwards, so that superfluous loads do not act on the pushbutton switches, and any maloperation can be prevented. Moreover, since the operation plate need not be pushed up by elastic arms being separate members, the number of components and the number of assembling man-hour are small, and the operation input device of high productivity is obtained.
As another embodiment according to the invention, elastic pads may well be arranged between the pushbutton switches and the operation plate.
According to this embodiment, the compressed elastic pads urge the operation plate upwards, and the vertical ricketiness can be prevented. Moreover, since the elastic pads absorb an assemblage error, a high assemblage precision is not required, and the fabrication of the operation input device is facilitated.
An electronic equipment according to the invention consists in that the operation input device mentioned above is mounted with the disc type operation dial exposed so as to be operable from outside.
According to the invention, there is the advantage that the electronic equipment which is capable of a smooth turning operation without vertical ricketiness is obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a front view of a portable telephone in which the first embodiment of an operation input device according to the present invention is incorporated;
FIG. 1B is an enlarged front view of the operation input device;
FIGS. 2A and 2B are perspective views in which the operation input device shown in FIGS. 1A and 1B is seen from above and from below, respectively;
FIG. 3 is an exploded perspective view in which parts of the operation input device shown in FIG. 2A are disassembled and seen from above;
FIG. 4 is an exploded perspective view in which the operation input device shown in FIG. 2A is seen from above;
FIG. 5 is an exploded perspective view in which parts of the operation input device shown in FIG. 2B are disassembled and seen from below;
FIG. 6 is an exploded perspective view in which the operation input device shown in FIG. 2B is seen from below;
FIGS. 7A , 7 B and 7 C are a front view of the operation input device shown in FIG. 1 , and sectional views taken along a line B-B and a line C-C indicated in FIG. 7A , respectively;
FIGS. 8A , 8 B and 8 C are a front view of the operation input device shown in FIG. 1 , and sectional views taken along a line B-B and a line C-C indicated in FIG. 8A , respectively;
FIGS. 9A and 9B are perspective views in which the second embodiment of the operation input device according to the invention is seen from above and from below, respectively;
FIGS. 10A and 10B are sectional views which correspond to the perspective views shown in FIGS. 9A and 9B , respectively;
FIG. 11 is an exploded perspective view in which the operation input device shown in FIG. 9A is seen from above;
FIG. 12 is an exploded perspective view in which the operation input device shown in FIG. 9B is seen from below;
FIGS. 13A , 13 B and 13 C are a front view of the operation input device shown in FIGS. 9A and 9B , and sectional views taken along a line B-B and a line C-C indicated in FIG. 13A , respectively;
FIGS. 14A and 14B are perspective views in which the third embodiment of the operation input device according to the invention is seen from above and from below, respectively;
FIGS. 15A and 15B are sectional views which correspond to the perspective views shown in FIGS. 14A and 14B , respectively;
FIG. 16 is an exploded perspective view in which the operation input device shown in FIG. 14A is seen from above;
FIG. 17 is an exploded perspective view in which the operation input device shown in FIG. 14B is seen from below;
FIG. 18 is a schematic sectional view showing the operating principle of the operation input device according to the invention; and
FIG. 19 is schematic sectional views showing the operating principle of an operation input device in a prior-art example.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of an operation input device according to the present invention will be described in conjunction with the accompanying drawings of FIG. 1A through FIG. 18 .
The operation input device in each embodiment is applied to a portable telephone. As shown in FIGS. 1A and 1B , a scroll bar (not shown) within a monitor 2 disposed in the portable telephone 1 is scrolled by the operation input device 3 , whereby a selection instruction can be given through a pushbutton 40 , etc. to be stated below. Incidentally, numeral 4 designates ten-keys, numeral 5 a microphone, and numeral 6 a loudspeaker.
As shown in FIGS. 4 and 6 , the operation input device 3 includes a metal base 10 on and with which a flexible printed circuit board 20 is stuck and united, a resin-made film cover 30 which has a center pushbutton switch 29 a and four pushbutton switches 29 b - 29 e stuck on its underside beforehand, the pushbutton 40 which operates the center pushbutton switch 29 a , an operation plate 50 which is supported on the metal base 10 , a slide sheet 60 which is placed on the upside of the operation plate 50 , and an operation dial 70 which has an annular magnet 65 fitted and fixed and has a fixation ring 45 clinched and fixed on its underside and which is turnably mounted on the operation plate 50 .
As shown in FIG. 4 , the metal base 10 is substantially rectangular in plan, and it has a pair of positioning pillars 11 , 11 cut and erected at its central parts and is provided with jig holes 12 , 12 outside the respective positioning pillars. Besides, the metal base 10 has elastic engagement receivers 13 cut and erected centrally of the edges of its respective latera.
The printed circuit board 20 made of a flexible resin film is formed of a circuit board body 20 a of substantially rectangular shape, whose rear surface is coated with a bonding material and is clad with peeling paper, and a lead portion 20 b which extends from the circuit board body 20 a . Here, the circuit board body 20 a is centrally provided with a concentric conductive portion 21 a , and it has concentric conductive portions 21 b , 21 c , 21 d , 21 e arranged crosswise about the conductive portion 21 a thereon. Besides, the printed circuit board 20 is provided with positioning holes 22 and jig holes 23 at positions which correspond respectively to the positioning pillars 11 and jig holes 12 of the metal base 10 . Further, LEDs 24 for notifying an operating state are mounted on the respective corner parts of the circuit board body 20 a , and a pair of Hall elements 25 a , 25 b are mounted on this circuit board body 20 a so as to oppose to each other with the conductive portion 21 a interposed therebetween.
Incidentally, the conductive portions 21 a - 21 e are not restricted to only the concentric ones. Each of these conductive portions may well be, for example, such that one conductive portion which is substantially C-shaped in plan has the other conductive portion arranged centrally so as to be led out.
The resin-made film cover 30 has a planar shape in which this film cover can be mounted on the circuit board body 20 a . This resin-made film cover 30 is provided with sticking portions 31 a - 31 e at those positions of its rear surface coated with a bonding material which correspond to the respective conductive portions 21 a - 21 e . Flat dome-shaped inversion springs which form the pushbutton switches 29 a - 29 e , are respectively stuck to the sticking portions 31 a - 31 e . Further, the resin-made film cover 30 is provided with positioning holes 32 and jig holes 33 at positions which correspond respectively to the positioning pillars 11 and jig holes 12 of the metal base 10 .
The pushbutton 40 has an outer peripheral shape in which this pushbutton can be inserted into the operation hole 71 of the operation dial 70 to be stated later. A coming-off preventive annular rib 41 is unitarily molded at the edge part of the lower end of the outer periphery of the pushbutton 40 . Besides, the pushbutton 40 is protrusively provided with a depressing lug 42 ( FIG. 6 ) centrally of its bottom surface, and it is formed with guiding slits 43 which engage the respective positioning pillars 11 of the metal base 10 , in the outer peripheral surface of the annular rib 41 .
The fixation ring 45 is clinched and fixed onto the underside of the operation dial 70 to be stated later, thereby to turnably assemble the operation dial 70 to the operation plate 50 .
The operation plate 50 is a resin-molded article which is substantially rectangular in plan, and which can cover the metal base 10 . This operation plate 50 is centrally provided with a fitting hole 51 , and it is formed with an annular step 52 at the peripheral edge part of the underside of the fitting hole 51 ( FIG. 6 ). Besides, the operation plate 50 is protrusively provided with depressing lugs 53 b - 53 e at positions which correspond to the respective sticking portions 31 b - 31 e of the resin-made film cover 30 . Further, the operation plate 50 is provided with rectangular holes 54 at positions which correspond to the respective Hall elements 25 a , 25 b , and it is provided with elastic pawls 55 centrally of the edge parts of the respective latera in a manner to protrude sideward. Incidentally, the rectangular holes 54 are provided in order to facilitate the passages of magnetic fluxes.
The slide sheet 60 has a concentric circular shape in which this slide sheet can cover the upside of the operation plate 50 , and it is provided with elastic tongues 61 which engage the respective elastic engagement receivers 13 of the metal base 10 , at its outer peripheral edge parts.
The annular magnet 65 has N-poles and S-poles arranged alternately, and it is fitted and fixed into the annular groove 75 of the operation dial 70 to be stated later. In particular, according to this embodiment, the annular magnet 65 is embedded in the annular groove 75 of the operation dial 70 , and it does not lie in direct touch with the slide sheet 60 . This brings forth the advantage that the operation input device 3 of thin type in which a frictional resistance acting on the operation dial 70 is low and which can be smoothly operated is obtained.
The operation dial 70 is centrally provided with the operation hole 71 into which the pushbutton 40 is fitted, and it is provided with antiskid raises 72 at the peripheral parts of its upside in a manner to extend radially and to lie at equal pitches. Besides, as shown in FIG. 6 , the operation dial 70 is concentrically provided with an annular protrusion 73 for clinching and fixing the fixation ring 45 , at the peripheral edge part of the underside of the operation hole 71 , and it is protrusively provided with clinching projections 74 on the lower surface of the annular projection 73 . Further, the operation dial 70 is concentrically provided with the annular groove 75 for fitting and fixing the annular magnet 65 thereinto, outside the annular protrusion 73 . Incidentally, the disc type operation dial 70 need not always be circular, but it may well be in the shape of, for example, an equilateral octagon as long as it is turnable.
Next, there will be described a process for assembling the constituent components stated above.
First, the jig holes 12 of the metal base 10 are respectively set to one pair of positioning pins of a jig not shown, thereby to position this metal base 10 . Subsequently, the jig holes 23 and positioning holes 22 of the printed circuit board 20 on which the Hall elements 25 a , 25 b and the LEDs 24 are mounted at their predetermined positions are respectively set to the pair of pins of the jig and the positioning pillars 11 of the metal base 10 , thereby to stick and unite the printed circuit board 20 to and with the metal base 10 . Further, the dome-shaped inversion springs to become the pushbutton switches 29 a - 29 e are respectively stuck and united to and with the sticking portions 31 a - 31 e of the resin-made film cover 30 . Besides, the jig holes 33 and positioning holes 32 of the resin-made film cover 30 are respectively set to the pair of positioning pins of the jig and the positioning pillars 11 of the metal base 10 , whereby the resin film 30 is stuck and united to and with the printed circuit board 20 , and the pushbutton switches 29 a - 29 e made up of the inversion springs stuck to the resin film 30 are formed.
On the other hand, the annular magnet 65 is fitted into the annular groove 75 of the operation dial 70 and is bonded and fixed thereto. Besides, the slide sheet 60 is positioned onto the upside of the operation plate 50 , and the annular protrusion 73 of the operation dial 70 is fitted into the fitting hole 51 . Further, the fixation fitting 45 is positioned to the annular protrusion 73 of the operation dial 70 , and the clinching projections 74 of the annular protrusion 73 are inserted into the clinching holes 46 of the fixation fitting 45 and are clinched. Thus, the operation plate 50 and the slide sheet 60 are held between the operation dial 70 and the fixation ring 45 , and the operation dial 70 is turnably supported on the operation plate 50 through the slide sheet 60 .
Besides, as shown in FIG. 3 , the pushbutton 40 is positioned over the pushbutton switch 29 a of the printed circuit board 20 . Further, the pushbutton 40 is fitted into the fitting hole 71 of the operation dial 70 , and the elastic pawls 55 of the operation plate 50 and the elastic tongues 61 of the slide sheet 60 are engaged with the elastic engagement receivers 13 of the metal base 10 , whereby the assembling operations are completed. Here, the elastic tongues 61 of the slide sheet 60 are engaged with the elastic engagement receivers 13 in a state where they are somewhat bent downward, so as to generate urging forces.
According to this embodiment, the operation plate 50 is unturnably fixed to the base 10 , and the operation dial 70 is depressed, thereby to bear the depression operation function of depressing the pushbutton switches 29 a - 29 e . On the other hand, the operation dial 70 turnably assembled onto the upside of the operation plate 50 is turned, thereby to bear a turning operation function.
Thus, according to this embodiment, the elastic pawls 55 of the operation plate 50 are held in engagement with the elastic engagement receivers 13 of the base 10 , so that the operation plate 50 can be prevented from becoming rickety in a horizontal direction.
Moreover, the operation plate 50 is urged upwards by the spring forces of the pushbutton switches, so that it undergoes no ricketiness in a vertical direction.
Furthermore, the elastic tongues 61 of the slide sheet 60 are held in engagement with the elastic engagement receivers 13 , thereby to urge the operation plate 50 downwards, so that the vertical ricketiness of the operation plate 50 can be prevented more reliably. Besides, the slide sheet 60 urges the operation dial 70 also upwards. Therefore, the operation dial 70 can be restrained from excessively turning due to an inertial force, to bring forth the advantage that any erroneous operation is difficult to occur.
Incidentally, the operation plate 50 and the operation dial 70 may well be supported in such a way that only the elastic tongues 61 of the slide sheet 60 arranged between the operation plate 50 and the operation dial 70 are engaged with the elastic engagement receivers 13 of the base 10 .
Next, there will be described an operation method for the operation input device 3 of the above configuration.
When the operation dial 70 is turned, thereby to turn the annular magnet 65 unitarily with this operation dial, the changes of a magnetic field are respectively sensed by the pair of Hall ICs 25 a , 25 b , and a turning direction and a turning magnitude are detected on the basis of the sensed changes.
Besides, the results of the detections are reflected as the movement of the scroll bar on the screen display of the monitor 2 through a control circuit not shown. Subsequently, in a case where the scroll bar has arrived at a desired position, the pushbutton 40 is depressed, whereby the center pushbutton switch 29 a is operated by the depressing lug 42 so as to output a selection command.
Alternatively, the peripheral part of the operation dial 70 as corresponds to, for example, the depressing lug 53 e shown in FIG. 8B may well be depressed, thereby to invert and turn ON the inversion spring of the pushbutton switch 29 e lying directly under the depressing lug 53 e.
As shown in FIG. 9A through FIG. 13C , the second embodiment of the invention corresponds to a case where an operation plate 50 is urged upwards by elastic arms 14 which are cut and raised from the peripheral edge parts of a metal base 10 , thereby to prevent the operation plate 50 from becoming rickety in a vertical direction. The same parts as in the first embodiment are assigned the same reference numerals and signs, and they shall be omitted from description.
According to the second embodiment, the operation plate 50 is pushed upwards, so that superfluous loads do not act on pushbutton switches 29 a - 29 e , and any maloperation can be prevented. Moreover, since elastic arms being separate members are not required, the number of components and the number of assembling man-hour are small, and an operation input device of high productivity is obtained.
As shown in FIG. 14A through FIG. 17 , the third embodiment of the invention corresponds to a case where elastic pads 34 are respectively placed on pushbutton switches 21 a - 21 e through a resin-made film cover 30 . Incidentally, the same parts as in the first embodiment are assigned the same reference numerals and signs, and they shall be omitted from description. For the brevity of illustration, however, the resin-made film cover 30 is not shown in FIGS. 14A through 15C .
According to the third embodiment, the elastic pads 34 are placed so as to push an operation plate 50 upwards, whereby the operation plate 50 can be prevented from becoming rickety in a vertical direction. Especially, since the elastic pads 34 can absorb a cumulative error ascribable to the assemblage of a large number of components, a high assemblage precision is not required, and an operation input device easy of fabrication is obtained.
Incidentally, FIG. 18 illustrates the principle stated above. Elastic members urging the operation plate 50 in the figure correspond to the slide sheet 60 , elastic arms 14 and elastic pads 34 in the respective embodiments stated above.
Besides, the ricketiness may well be prevented in such a way that the elastic pads are arranged between the upside of the printed circuit board 20 and the underside of the operation plate 50 so as to urge this operation plate 50 upwards.
It is a matter of course that the operation input device according to the invention is not restricted to the portable telephone, but that it may well be applied to another mobile equipment or any other electronic equipment. | An operation input device includes a base, a printed circuit board which has a plurality of pushbutton switches and Hall elements mounted on its upside and which is stacked on and united with the base, an operation plate which is supported on the base so as to be vertically movable on the printed circuit board, and a disc type operation dial in which an annular magnet with N-poles and S-poles arranged alternately is assembled on the underside of this operation dial and which is turnably assembled on the upside of the operation plate. Here, the disc type operation dial is turned, thereby to sense the changes of the magnetic fluxes of the annular magnet by the Hall elements and to detect a turning direction, while the disc type operation dial is depressed, thereby to operate any of the pushbutton switches through the operation plate. The operation dial is prevented from becoming rickety in a horizontal direction, and it ensures a smooth turning operation, thereby to afford a good operation feeling. | 6 |
FIELD OF THE INVENTION
This invention relates to FIFO buffers generally and more particularly to a clocking scheme for allowing a contiguous memory array to be utilized with various width data words.
BACKGROUND OF THE INVENTION
It is well known to construct a first-in first-out(FIFO) buffer or memory array that reads various size data words. The prior art required a shift register scheme to generate a number of intermediate signals necessary to incorporate a fixed word width data pack into the memory array. To implement a clocking scheme that stores fixed width data words that are equal to the width of the individual cells in the FIFO buffer, a 16-bit multiplexer would be required. To extend the prior art scheme to a memory array that is twice as wide as the width of the input data word, a 32-bit shift register would be required. Specifically, a 32-bit shift register would be necessary for a 9-bit word design and a 16-bit shift register would be required for a 18-bit word design. The prior art did not allow a single decode block to be used for both the 9-bit and 18-bit devices. The prior art FIFO's used a "carousel" type data placement scheme that used a 16-bit shift register to directly control each of the section signals. To extend the prior art system to decode both a 9-bit and 18-bit word would require a 32-bit shift register. The implementation of a 32-bit shift register would cause extreme difficulty in routing the various signals to appropriately connect the outputs of the shift register to each of the section control blocks. The implementation of a 32-bit shift register would also consume more than twice the amount of chip area that a 16-bit shift register would consume.
Referring to FIG. 1, a prior art scheme is shown generally comprising a shift register 12, a set of multiplexers 14a, 14b, 14c and 14d and a set of memory arrays 16a, 16b, 16c and 16d. A single data input 18 presents an input to each of the multiplexers 14a-d. The 16-bit shift register 12 presents one of a set of control inputs 20a, 20b, 20c and 20d to each of the multiplexers 14a-d. When the control input 20a-d is present at the multiplexer 14a-d, the data input 18 is received and is presented to the appropriate memory array 16a-d. An individual control input 20a-d is required for each memory array 16a-d. As the number of memory arrays 16a-d increases, the number of control inputs 20 will also increase. Each of the select inputs 20a-d would need to be individually routed from the individual multiplexers 14a-d to the shift register 12. The routing necessary to appropriately connect the control inputs 20a-d between the shift register 12 and the multiplexers 14a-d increases. To expand the shift register 12 to a 32-bit shift register would require twice the amount of routing as well as an increased amount of chip real estate to implement the shift register 12. The increase in routing the control inputs 20a-d and the increased chip area makes the prior art scheme difficult to implement with multiple width data words.
SUMMARY OF THE INVENTION
The present invention provides a circuit for distributing data from a common input source to a number of individual memory cells in a memory array. The present invention uses a multi-bit counter to distribute a timing signal to a number of decoder blocks. Each of the decoder blocks receives both a data input signal and the timing signal at all times. When a particular timing signal is present at a given decoder, the input signal containing a fixed width data word is passed through to the corresponding memory array for storing the data word. The present invention reduces the number of internal signal lines necessary to implement the control function.
Objects, features and advantages of the present invention are to provide a control circuit for distributing data to a number of memory arrays for use with both synchronous and asynchronous FIFO's as well as other memory devices. The circuit produces the distributing effect using a minimum number of signal lines, eliminates the need to use a wide bit shift register, can be very easily adopted to larger or smaller memory organization systems with minimum design changes, consumes less overall chip real estate and can easily be adopted to denser and wider memory devices with multiple data input word widths.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, features and advantages of the present invention will be apparent from the following detailed description and the appended claims in which:
FIG. 1 is a block diagram of a prior art scheme;
FIG. 2 is a block diagram of the presently preferred embodiment of the invention;
FIG. 3 is a timing diagram illustrating the effect of the present invention using a 9-bit data word; and
FIG. 4 is a timing diagram illustrating the implementation of the present invention using an 18-bit data word.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 2, a block diagram of a clocking circuit 30 is shown in accordance with a presently preferred embodiment of the invention. The clocking circuit 30 generally comprises a data input 32, a counter 34, a set of decoder and multiplexers 36a, 36b, 36c and 36d and a memory array 38a, 38b, 38c and 38d. Each of the decoder and multiplexer blocks 36a-36d have a signal input 40 and a timing input 42. The signal input 40 of each of the decoder and multiplexer blocks 36a-36d is received from the data input 32. As a result, each of the decoder and multiplexer blocks 36a-36d receive the signal input 40 at all times. The signal input 40 comprises a stream of fixed width data words that can be either a single bit serial input or a multi-bit parallel input. While each of the decoder and multiplexer blocks 36a-36d will receive the signal input 40 at all times, only certain specific decoder and multiplexer blocks 36a-36d present an output to the corresponding memory array 38a-38d at any given time. The decoder and multiplexer block 36a-36d that presents data to the corresponding memory array 38a-38d at a particular time is determined by a signal present at the timing input 42. The timing input 42 receives a timing signal from a timing bus 44 connected to the counter 34. Each of the decoder and multiplexer blocks 36a-36d receive the timing signal at the timing input 42 at all times. The counter 34 produces the timing signal that is a unique multi-bit digital word that changes with each clock cycle. A 4-bit counter 34 produces a 4-bit digital word that produces 2 to the 4th, or 16, unique states. A 5-bit counter produces a 5-bit digital word that produces 2 to the 5th, or 32, unique states. As a result, the addition of a single bit to the counter 34 and the bus 44 doubles the capabilities of the clocking circuit 30. Each unique state produced by the counter provides a specific timing signal that only certain specific decoder and multiplexer blocks 36a-36d will respond.
A specific example of a particular implementation of the present invention will be described where the memory arrays 38a-d are 9-bit devices and the data input signal 32 is a stream of 9-bit digital words. When a first word is presented by the decoder and multiplexer block 36a to the memory array 38a, the decoder and multiplexer blocks 36b, 36c and 36d connected to the memory arrays 38b, 38c and 38d have a timing signal present at the timing inputs 42 and a stream of digital words present at the signal input 40, but do not present the stream of digital words to the memory arrays 38b, 38c and 38d. When the first digital word is completely loaded through the decoder and multiplexer block 36a to the memory array 38a, the timing signal will continue to be present at the timing input 42. The timing signal will then change and be recognized at the timing input 42 of the decoder and multiplexer block 36b connected to the memory array 38b. At this point a second digital word from the data input 32 will be loaded into the decoder and multiplexer block 36b connected to the memory array 38b. The decoder and multiplexer blocks 36a, 36c and 36d connected to the memory arrays 38a, 38c and 38d will not present the second digital word to the memory arrays 36a, 36c and 36d during this time. A similar input word loading is accomplished when the memory arrays 38c and 38d are loaded.
It should be appreciated that each of the memory arrays 38a, 38b, 38c and 38d have a corresponding decoder and multiplexer block 36a, 36b, 36c and 36d. Each of the decoder and multiplexer blocks 36a-36d recognize only a specific multi-bit timing signal present at the timing input 42. Only one of the decoder and multiplexer blocks 36a-36d recognizes the specific multi-bit timing word at any given clock cycle and processes the digital word present at the signal input 40. Effectively, each of the decoder and multiplexer blocks 36a-36d act as a digital valve. The digital valve effect of the decoder and multiplexer block 36 effectively opens when the proper multi-bit timing word is present at timing input 42, presenting an output to the appropriate memory array 38a-38d. Each of the decoder and multiplexers 36a-36d work in combination to completely load a digital word to one of the memory arrays 38a-38d on a given clock cycle before the next digital word from the data input 32 is loaded into the next appropriate memory array 38a-38d at the next clock cycle. The order of the loading of the memory arrays 38a-38d can be any order necessary to fit the particular design criteria of a given application. The sequential loading of memory array 38a, then 38b, then 38c, etc. is for illustrative purposes only.
The example illustrated using the 9-bit memory arrays 38a-d and the 9-bit digital words as the input signal 32 has a one word per timing signal organization. In an application where the width of the digital word is a multiple of the width of the memory arrays 38a-d, each fraction (i.e. one half, one third, one fourth, etc.) of the digital word would be loaded into a separate one of the memory arrays 38a-d on each clock cycle. As a result, the present invention would load a multi width digital word into the memory arrays 38a-38d.
It is generally advantageous for a manufacturer to produce the smallest number of components necessary to maintain all product lines in current production. As a result, from a practical aspect, the present invention would be implemented using a counter 34 that is five-bits wide for all applications that require either 16 unique states or 32 unique states. If only 16 unique states are required for a particular design application, only four of the bits on the counter would be used with one of the bits being disabled. For example, the most significant bit would be disabled if the counter 34 was implemented as an up counter. Other counters could be used that produce a unique state at each clock cycle, such as a random counter. The approach of providing additional bits in the counter 34 is practical since the addition of an additional counter output signal line would be less expensive than producing two separate parts. This is in contrast to the prior art where a 32-bit shift register is far more difficult to manufacture than a 16-bit shift register. To maintain a single component using the prior art techniques, the much more complex 32-bit shift register would have to be produced on each device, even if only a 16-bin shift register portion is actually used.
Referring to FIG. 3, a timing diagram illustrating the functioning of the present invention when operating with a series of 9-bit data words as an input is shown. It should be appreciated that the example illustrated in FIG. 3 uses a 9-bit digital word for illustrative purposes only. Any fixed width digital word, including a single bit word, could be used without departing from the spirit of the invention. FIG. 3 generally comprises a Wclk signal clock 50, a dlatA signal 52, a dlatB signal 54, a dlatC signal 56 and a dlatD signal 58. The dlatA, dlatB, dlatC and dlatD signals provide pulses that represent when a word is loaded into a corresponding memory array 38a-38d. The digital high portions of the Wclk clock 50 are shown as pulses 61, 62, 63, 64, 65, 66, 67 and 68.
When the Wclk clock 50 is high at pulse 61, the dlatA signal 52 is shown as being high at a pulse 71. This loads a full 9-bit digital word into the memory array 38a. When the Wclk clock 50 is high at the pulse 62, the dlatB signal 54 is shown having a pulse 72. When the Wclk clock 50 is shown as being high at the pulse 63, the dlatC signal 56 is shown as being high at a pulse 73. Similarly, when the Wclk clock 50 is shown as being high at the pulse 64, the dlatD signal 58 is shown as being high at a pulse 74. The pulses 71, 72, 73 and 74 represent the loading of a 9-bit digital word to a respective one of the memory arrays 38a, 38b, 38c and 38d. After the dlatD signal 58 receives an input shown as the pulse 74, the next data word is loaded into memory array 38a when the dlatA signal 52 is high at a pulse 75. A similar effect is shown with a pulse 76, a pulse 77 and a pulse 78. A direct relationship is shown where a single word is written to the memory array 38a, then a single digital word is written to the memory array 38b, then a single digital word is written to the memory array 38c and finally a single digital word is written to the memory array 38d. After the digital word is written to the memory array 38d, the process starts again with writing a digital word to the memory array 38a.
It should be appreciated that the number of memory arrays 38a-38d is shown to be four for illustrative purposes only. The number of memory arrays 38a-d can be extended to any number of memory arrays desired for a particular design application or can be reduced to a single memory array. Increasing or decreasing the number of memory arrays would only require replacing the counter 34 with a counter having a sufficiently wide bit path to provide a sufficient number of independent states to accommodate The number of words written into the number of memory arrays 38a-d that are implemented. The width of the bit path would be determined by the width of the digital word, the width and number of the memory arrays 38a-d and the desired order of the loading of the memory arrays 38a-d. To accommodate these adjustments, the width of the bit path may have to be increased, decreased or left unchanged. The order of the loading of the memory arrays 38a-38d can be any order necessary to fit the particular design criteria of a given application. The sequential loading of memory array 38a, then 38b, then 38c, etc. is for illustrative purposes only.
Referring to FIG. 4, an 18-bit data word width implementation of the present invention is illustrated. It should be appreciated that an 18-bit digital word is used for illustrative purposes. The 18-bit data word is considered a double width digital word as compared to the width of the memory arrays 38a-38d. Any multiple of the width of the memory array can be used. FIG. 4 generally comprises a Wclk clock 80, a dlatA signal 82, a dlatB signal 84, a dlatC signal 86 and a dlatD signal 88. Since the data word is 18-bits wide and the individual memory arrays 38a-38d are 9-bits wide, a slightly different loading protocol is established. The 18-bit digital word is broken into a number of fractional portions. The digital high portions of the Wclk clock 80 are shown as pulses 91, 92, 93, 94, 95, 96, 97 and 98.
When the Wclk clock 80 is high at the pulse 91, a first fraction, or half, of a 18-bit digital word is loaded into the memory array 38a and is shown as a pulse 101 on the dlatA signal 82. A second fraction, or half, of the 18-bit digital word is loaded into the memory array 36b and is shown on the dlatB signal 84 as a pulse 102. When the Wclk clock 80 is high at the pulse 92, a first fraction, or half, of the next 18-bit digital word is loaded into the memory array 36c as shown on the dlatC signal 86 as a pulse 103. The second fraction, or half, of the 18-bit digital word is loaded into the memory array 36d as shown on the dlatD signal 88 at a pulse 104. When the Wclk clock 80 is high at the pulse 93, a first fraction, or half, of the next 18-bit digital word is loaded into the memory array 36a as shown as pulse 105 of dlatA signal 82. A second fraction, or half, of the 18-bit digital word is loaded into the memory array 38b as shown by the pulse 106 on the dlatB signal 84. A series of pulses 107, 108, 109, 110, 111, 112, 113, 114, 115 and 116 show similar splitting of 18-bit digital words between either the dlatA signal 82 and dlatB signal 84 or the dlatC signal 86 and the dlatD signal 88. Each of the pulses 101-116 illustrates a 9-bit half of an 18-bit digital word loaded into one of the 9-bit wide memory arrays 38a-38d. The order of which memory arrays 38a-38d are loaded can be adjusted to fit the design criteria of a particular application by programing the decoder and multiplexers 36a-36d to respond to a timing signal that produces a non-sequential loading of the memory arrays 38a-d.
The example of the present invention illustrated in FIGS. 3 and 4 can be extended to larger or smaller width digital words. While the FIG. 4 illustration was limited to a double width digital word, a triple, quadruple or other width digital word could be accomplished by extending the plurality of fractional portions of the word accordingly. The clocking circuit 30 can be programmed to accept any multiple width digital word. The programming can be either during production of the clocking circuit 30, after production by using an external device to program the clocking circuit 30 or by any other programing scheme contemplated. Larger or smaller width memory arrays 38a-38d could also be accommodated. Also, a larger or smaller number of memory arrays 38a-38d could also be included. In any of the above modifications, the size of the counter 34 would have to be adjusted accordingly. This adjustment would be minor since the addition of a single bit to the counter 34 doubles the number of possible independent states.
It is to be understood that modifications to the invention might occur to one with skill in the field of the invention within the scope of the appended claims. | The present invention provides a circuit for distributing data from a common input source to a number of individual memory cells in a memory array. A multi-bit counter is used to distribute a timing signal to a number of decoder blocks. Each of the decoder blocks receives both a data input signal and the timing signal at all times. When a particular timing signal is present at a given decoder, the input signal containing a fixed width data word is passed through to the corresponding memory array for storing the data word. The present invention reduces the number of internal signal lines necessary to implement the control function and significantly reduces the chip area needed to generate the signal lines. | 6 |
FIELD OF THE INVENTION
The present invention relates to improvements to a fastener, and relates in particular, though not exclusively, to improvements to a threaded fastener suitable for fastening a grinding wheel, circular saw blade or carving disk and the like to the spindle of a power tool.
BACKGROUND TO THE INVENTION
Copending Australian Patent Application No. 85296/91 describes a threaded fastener suitable for securing a grinding wheel to the spindle of an angle grinder. The fastener comprises a first disk-shaped component having a first pressure transmitting surface adapted to bear against the grinding wheel, and a second disk-shaped component having a threaded hub non-rotatably fixed thereto. The first and second components are assembled on the hub so as to be rotatable with respect to each other, and the second component is adapted to apply an axially directed compressive force to press the first component against the grinding wheel when a torque is applied to the second component. A solid dry lubricant washer is provided between the first and second components in an annular recess immediately adjacent the hub, for reducing friction, when one of the components is rotated relative to the other. The lubricant washer insures that a significantly increased proportion of the torque applied to the second component is converted to compressive force transmitted through the first component to the grinding wheel.
While the performance of the above-described threaded fastener is entirely satisfactory and represents a great advance upon the art, the second component is typically of complex design and, as it normally carries the full clamping pressure of the nut, must be made from metal. This requires either a complex NC-machining process or the use of sintered powder metallurgy. It would be desirable if a part with such a complex shape could be made from plastics material by injection moulding or by die-casting. In practice, it has also proved difficult for a user to judge whether the fastener has been adequately tightened, due to the fact that the turning friction normally associated with tightening has been substantially eliminated. There is thus a danger of overtightening of the fastener.
SUMMARY OF THE INVENTION
The present invention was developed with a view to providing a number of improvements to the design of the above fastener.
According to one aspect of the present invention there is provided an improved fastener comprising:
first and second disc-shaped components assembled so as to be rotatable with respect to each other about a common axis, said first component having a pressure transmitting portion and a resilient flexing portion, said pressure transmitting portion being adapted to bear against an object to be fastened and being radially spaced from said common axis, said second component having a threaded portion provided in connection therewith and being adapted to apply an axially directed compressive force to press the pressure transmitting portion against said object when a torque is applied to said second component and wherein said flexing portion is adapted to allow the first component to flex when the pressure transmitting portion is pressed against said object so as to apply a clamping pressure to said object, said second component being provided with a recessed annulus within which said first component is rotatably received and wherein said recessed annulus is adapted to accommodate the flexing of the first component; and,
a solid dry lubricant material having a low coefficient of friction provided between said first and second components to reduce friction therebetween when one of the components is rotated relative to the other whereby, in use, said solid dry lubricant material can ensure that a significantly increased proportion of the torque applied to said second component to fasten said object can be converted to said compressive force transmitted to the object through said pressure transmitting portion.
Preferably the improved fastener further comprises containment means provided in connection with said first and second components for containing said solid dry lubricant material therein whereby, in use, said solid dry lubricant material is capable of withstanding substantial compressive loads without being forced from between the first and second components.
Typically said pressure transmitting portion is in the form of an annular protrusion adapted to bear against the object to be fastened. Advantageously said recessed annulus has a radially inclined surface which faces a surface on the first disk-shaped component. Preferably said radially inclined surface of the second disk-shaped component forms a diminishing thickness dimension of the second disk-shaped component in a radially outwards direction.
Typically the second disk-shaped component is provided with a hub incorporating said threaded portion, said hub being received in an aperture provided in the first disk-shaped component whereby said first and second disk-shaped components share said common axis of rotation. Preferably said solid dry lubricant is in the form of a closed ring located concentrically between said disk-shaped components and typically lying immediately adjacent an outer periphery of said hub. Advantageously said hub has a shoulder and said first disk-shaped component is provided with an annular recess adapted to rotatably receive said shoulder therein, said annular recess having said dry lubricant ring contained therein, and wherein the height of said shoulder relative to the depth of said annular recess is selected so that said facing inclined surfaces of the components are normally separated by an air gap.
Preferably said improved fastener further comprises a seal ring Located between an outer periphery of said first component and an outer periphery of said recessed annulus for inhibiting the ingress of contaminants into the air gap between the components, The seal ring is preferably made from a solid dry lubricant material having a low coefficient of friction. Advantageously either one of said first and second components is provided with an annular lip for retaining said seal ring in place. In addition, the seal ring may have a resilient biasing spring, for example, a spring steel split-ring, for biasing the seal ring against the outer periphery of either said first component or said recessed annulus.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to provide a more comprehensive understanding of the nature of the invention a preferred embodiment will now be described, by way of example only, with reference to the accompanying drawings in which;
FIG. 1 is a part section view through an embodiment of the improved fastener according to the invention;
FIG. 2 is similar to FIG. 1 and illustrates the fastener in use;
FIG. 3 is an enlargement of part of the fastener illustrated in FIG. 2;
FIG. 4 is a variation of the part illustrated in FIG. 3;
FIG. 5 illustrates a second embodiment of the improved fastener according to the invention; and,
FIG. 6 illustrates a third embodiment of the improved fastener according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
A preferred embodiment of the improved fastener 10 according to the invention is illustrated in FIGS. 1 and 2. The fastener 10 comprises a first disk-shaped component 12 having a pressure transmitting portion 14 adapted to bear against an object to be fastened. In FIG. 2, the object to be fastened is a grinding disk 16 to be fastened to the spindle of an angle grinder (not illustrated). The pressure transmitting portion 14 of this embodiment is in the form of an annular protrusion which is radially spaced from a central axis of rotation 18 of the fastener 10.
The fastener 10 further comprises a second disk-shaped component 20 assembled with the first disk-shaped component so as to be rotatable with respect to each other about the common axis of rotation 18. The second disk-shaped component 20 is provided with a hub 22 non-rotatably fixed thereto and incorporating a threaded portion adapted to be threaded onto the spindle of the angle grinder. The second disk-shaped component 20 together with hub 22 is adapted to apply an axially directed compressive force to press the pressure transmitting portion 14 of the first disk-shaped component 12 against the object, when a torque is applied to the second component 20. A flap 30 is provided, that can be pivoted to lie substantially parallel to axis 18, for applying a torque manually to the second component 20.
Advantageously, the first component 12 is adapted flex when the pressure transmitting portion 14 is pressed against the object to be fastened. The first component 12 is preferably designed to have a reducing thickness dimension or taper in a radially inwards direction, so that it has a minimum thickness immediately adjacent hub 22. Hence, when a load is applied proximate the centre of the first component 12 it is able to flex or bend at the thinnest point. The material of the first component 12 is selected to be resilient, for example, spring steel or a resilient plastics material, so that when the load is released it returns to its original shape. This is illustrated most clearly in FIG. 2, where it can be seen that an air gap between the first component 12 and the second component 20 has been reduced compared with FIG. 1, as a compressive load is applied to the first component 12. The air gap between the first and second components is typically between 1.0 to 1.5 mm wide. A bending moment is produced in the first component 12 at the point of contact of pressure transmitting portion 14 with the grinding disk 16. The degree of flex of the first component 12 is partly determined by the resilience and thickness of the first component 12. This will vary for different sized fasteners designed for various applications.
The principal advantages of designing the first component 12 so that it can flex when an axially directed compressive force is applied thereto, are as follows:
(1) The first disk-shaped component 12 acts as a spring and the spring force generated when it flexes provides additional pre-loading on the spindle of the angle grinder to maintain sufficient frictional contact between the grinding disk and the backing plate;
(2) The subjective "feel" of the fastener is improved, due to the degree of "give" provided by the flexing of the first component 12 which helps the user judge how much clamping pressure is being applied;
(3) It helps to avoid overloading of the grinding disk due to overtightening of the fastener;
(4) There is a degree of mechanical advantage obtained due to the spaced location of the annular protrusion 14 from the central axis of rotation 18, and more particularly from the thread of hub 22; and,
(5) In view of (4) above, the grinding disk 16 can be held more securely against the backing plate provided on the spindle of the angle grinder as the load is applied primarily at a location spaced outwardly from the centre of the disk, which is the preferred location. Furthermore, it is known that stress fractures are most likely to form immediately adjacent the central aperture in the grinding disk. Hence, by applying the clamping pressure radially spaced from the central aperture the stresses in the disk can be reduced and the disk is less likely to fly off the spindle in the event of failure.
As a load is applied to the grinding disk 16 via pressure transmitting portion 14, the first component 12 may flex sufficiently for the centre region of the first component 12 to come into contact with the disk 16 adjacent its central aperture. The first component 12 typically flexes to produce from between 0.5 to 1.0 mm of travel. The pressure transmitted to the disk 16 adjacent its central aperture may provide additional hold down pressure. However in most applications this is undesirable as it diminishes the mechanical advantage and improved clamping pressure noted in (4) and (5) above. The spring force in the first disk-shaped component 12 is preferably sufficient to provide adequate clamping pressure, (via annular protrusion 14 when flexed between 0.5 to 1.0 mm), without bottoming out.
In some applications, for example, when fastening a saw blade or rotary cutter which are not as thick as grinding disks, it is possible that hub 22 may come into contact with the backing plate on the angle grinder. Normally, one would simply change the backing plate to suit the application. However, if desired, the protruding end of hub 22 may be provided with a solid dry lubricant washer or bearing arrangement to reduce the friction between the end of the hub and the backing plate.
Similar to the fastener of PCT/AU91/00420, the improved fastener 10 further comprises a solid dry lubricant material having a low co-efficient of friction provided between the first and second components to reduce friction therebetween when one of the components is rotated relative to the other. In this embodiment the solid dry lubricant is in the form of a closed ring or washer 24 located concentrically between the disk-shaped components 12, 20 and lying immediately adjacent an outer periphery of the hub 22. Clearly the solid dry lubricant may take any suitable form, for example, a series of radially extending sections. The solid dry lubricant washer 24 ensures that a significantly increased proportion of the torque applied to the second component 20 is converted to a compressive force transmitted to the grinding disk 16 through the pressure transmitting portion 14. It also overcomes the problem of overtightening caused by slipping of the grinding disk, and it enables the fastener to be tightened and loosened by hand.
In this embodiment, hub 22 is provided with a shoulder 26 defined between an upper larger diameter portion 25 and a lower smaller diameter portion 27 of the hub 22, and the first component 12 is provided with an annular recess 28 adapted to rotatably receive the shoulder 26 therein. Annular recess 28 has the lubricant washer 26 located therein. Either one or both of annular recess 28 and shoulder 26 may be manufactured from stainless steel to provide a smooth pressure transmitting surface that bears against washer 24. The hub 22 and annular recess 28 effectively contain the solid dry lubricant material therein so that, in use, the washer 24 is capable or withstanding substantial compressive loads without being forced from between the first and second components 12, 20. The first and second components are accurately fitted to hub 22 to ensure concentric rotation. The height of the shoulder 26, the depth of annular recess 28 and the thickness of washer 24 are selected so that the facing inclined surfaces of the disk-shaped components are normally separated by an air gap. Ideally the hub 22 has a minimum wall thickness in the region of the smaller diameter portion 27. Thus, for example, with an angle grinder spindle outside diameter of 14 mm, the outside diameter of the portion 27 is approximately 17 mm. The first disk-shaped component 12 is retained on the portion 27 of hub 22 by any suitable means, in this case a retaining ring 29 shrink-fitted to portion 27.
In the illustrated embodiment, the second component 20 does not have any pressure transmitting surfaces provided directly thereon, the only pressure transmitting surface provided in connection therewith being that provided on shoulder 26 of the hub 22. Hub 22 is typically manufactured separately from the second component 20 and the outer surface of portion 25 is formed with splines (not illustrated) which engage with corresponding internal splines on the second disk-shaped component 20. The second disk-shaped component 20 is therefore provided purely to enable a torque to be applied to hub 22 and no facilitate manual tightening and loosening of the fastener by means of a gripping device in the form of flap 30, similar to that described in PCT/AU91/00420.
A significant advantage of providing the pressure transmitting surface of the second component on hub 22 is that the fastener then fully complies with Australian Standards specifications, in which the threaded part of a fastener should hold down the washer for safety reasons. Therefore, even if the disk-shaped component 20 should become separated from hub 22, the fastener will remain securely fastened to the spindle of the angle grinder. A further significant advantage is that the second disk-shaped component can be manufactured from a suitable plastics material by injection moulding. This greatly simplifies and reduces the cost of manufacturing the second disk-shaped component 20 which is of relatively complex shape to accommodate a pivotable connection of flap 30.
The second disk-shaped component 20 of this embodiment is provided with a recessed annulus 32 within which the first disk-shaped component 12 is rotatably received. Recessed annulus 32 is provided with a radially inclined surface 34 which faces a matching radially inclined surface 36 on the first component 12. The angle of inclination of surface 36 is different from that of surface 34 in order to provide an enlarged air gap to accommodate the flexing of the first component 12. Furthermore, radially inclined surface 34 forms a diminishing thickness dimension of the second component 20 in a radially outwards direction. This is advantageous in so far as it enables a maximum thickness dimension to be maintained adjacent the hub where maximum strength of the second component 20 is required, both to ensure the integrity of the connection with hub 22 and to accommodate a groove (not illustrated) within which the hinge connection of flap 30 is provided.
In order to inhibit the ingress of contaminants into the air gap between the first and second components 12, 20, a seal ring 38 is located between an outer periphery 40 of the first component 12 and an outer periphery 42 of the recessed annulus 32. The seal ring 38 is preferably made from a solid dry lubricant material having a low coefficient of friction, similar to that of the lubricant washer 24. It is desirable that the material of seal ring 38 have the lowest possible coefficient of friction so that its presence between the outer peripheries 40, 42 causes minimum friction therebetween. The configuration of the seal ring 38 is illustrated more clearly in FIG. 3, which is an enlargement of the part of the fastener circled in FIG. 2. In this embodiment, the outer periphery 40 of the first component 12 is provided with an annular lip 44 for retaining the seal ring 38 in place. Advantageously, the seal ring 38 may have a resilient biasing spring, (not illustrated), for example, a spring steel split-ring, for biasing the seal ring against the outer periphery of the first component 12 or recessed annulus 32. This may be desirable to maintain a seating fit of the seal ring 38 if the material of the seal ring is not itself capable of holding its original shape, ie, if it is not resilient.
The solid dry lubricant material of washer 24 and seal ring 38 is typically a fluoropolymer plastic having a low coefficient of friction such as PTFE, commonly known as teflon. Advantageously, the teflon may be reinforced with a filler material such as ground glass in order to improve its compressibility.
FIG. 4 illustrates a variation of the arrangement of the seal ring 38 between the first and second components 12, 20 respectively. In this embodiment, the seal ring 38 is profiled to fit beneath a lip provided on the outer periphery of the first component 12.
FIGS. 5 and 6 illustrate second and third embodiments of the improved fastener respectively in which parts having the same or similar function are given the same reference numerals as the embodiment of FIGS. 1 and 2. The fastener in FIG. 5 is shown in exploded or disassembled form. As before the first component 12 is provided with an annular recess 28 to accommodate the washer 24 (and to prevent its distortion or extrusion under pressure). However, the first component 12 of this embodiment is also provided with a second annular recess 48 on the underside for containing a second low-friction washer 50. A bow spring-steel or bronze washer 52 is fitted in recess 28 under washer 24 to keep it in firm contact with shoulder 26, and a similar spring washer 54 is fitted under low-friction washer 50 to keep it firmly located in recess 48.
It will be appreciated that when the device of FIG. 5 is assembled like that of FIG. 1, the upper load-bearing faces of low-friction washers 24 and 50 are kept in firm contact with shoulder 26 and the first component 12 respectively so that grit and dirt are excluded.
Another modification to the fastener of this embodiment is in the shape of the first component 12, which is dished so that the undersurface is concave. Hence, when the fastener presses against the grinding disk (not illustrated in FIG. 5) or other tool element, the only part of the fastener that is in pressure-transmitting contact with the disk is a pressure transmitting portion 14 proximate the outer periphery of the facing surface of the first disk-shaped component 12. The outer periphery of the first disk-shaped component 12 is formed with an annular protrusion 14. The first component 12 is adapted to flex in a similar manner to that of the first embodiment when the pressure transmitting portion is pressed against the grinding disk.
The third embodiment of FIG. 6 is similar to that of FIG. 5 except that the first component 12 is formed as a disk-like spring plate, the outer periphery 14 of which bears against the outer face of the grinding disk 16 and acts as the pressure transmitting portion of component 12. Preferably, for reasons made clear in the second embodiment described above, a coil-spring or helical spring washer 56 is located under the inner face of the spring plate 12 so as to bear against the retaining ring 29 and bias the spring-plate against the low-friction washer 24 no exclude grit and dirt from its load-bearing interfaces.
Now that preferred embodiments of the improved fastener have been described in detail it will be apparent that numerous variations and modifications can be made, in addition to these already described, without departing from the basic inventive concepts. For example, the hub 22 need not be manufactured separately from the second component 20 but may be manufactured integral thereto. Furthermore, the first and second components 12, 20 need not be disk-shaped, this shape being merely preferred for ease of manufacture and for aesthetic reasons. Also, the improved fastener is not limited in application to power tools, it can be used in any situation where it is desirable to be able to convert a higher percentage of the applied torque to compressive force. All such variations and modifications as would occur to a person skilled in the mechanical arts are to be considered within the scope of the present invention, the nature of which is to be determined from the foregoing description and the appended claims. | An improved fastener assembly is disclosed comprising a threaded fastener combined with two disc shaped washer components wherein one disc component is resilient and mounted to relatively rotate with respect to the threaded fastener and other disc component. A dry lubricant material is provided between the disc components to facilitate the relative rotation. | 5 |
FIELD
The present disclosure relates to vent assemblies and, more particularly, to a mechanism for raising and lowering the top cover.
BACKGROUND
In motor vehicles, such as motor coaches, that include a living area, it is desirable to have a vent assembly that enables the interior of the coach to vent to the outside. Ordinarily, a vent assembly is utilized that is capable of moving air either into or out of the interior of the motor coach. One such fan assembly is illustrated in U.S. Pat. No. 4,633,769 entitled “Roof Vent Fan Assembly”.
When the motor coach is being driven, it is desirable to have the cover in a down position. However, it is also possible that the cover may be raised to enable the interior to vent. The above vent assembly includes an arm to raise and lower the cover between an open and closed position. The arm is directly connected to a bracket that is coupled with the cover.
The disclosure provides a strut system that connects with an arm and with the cover. The strut system provides two connecting positions to retain the cover onto the base. The system provides an over center retention force to maintain the cover on the base.
SUMMARY
According to a first aspect of the disclosure, a vent assembly comprises a base that is secured in an opening in a vehicle. A cover is connected with the base. The cover is movable between an open and a closed position. Optionally, a fan is mounted for rotation within an opening in the base. A mechanism raises and lowers the cover between the open and closed position. The mechanism includes a strut system connected to the cover at two positions that are spaced from one another. When the cover is in a closed position, a force is provided by the strut system which is distributed about the cover to maintain the cover on the base. The cover includes a hinge on one side of the base. The two connections are positioned on the cover spaced away from the hinge side and on opposite sides of the fan. The strut system includes a U-shape strut coupled with a pair of brackets mounted on the cover to assist in raising and lowering the cover. The cover has a rectangular configuration with the hinge along one side and the two connection positions along the two sides perpendicular to the hinge side, both positions extending towards the opposite parallel side. The mechanism includes an arm connected with the U-shaped strut. The arm includes a pronged receptacle to receive a leg of the U-shaped strut. A pair of bearing blocks are positioned on the base to receive a web of the U-shaped strut. The bearing blocks position the U-shaped strut on the base. The connecting positions extend beyond a mid-line of the cover away from the hinged side to provide an over center force to retain the cover in the closed position.
According to a second aspect of the invention, a mechanism to raise and lower a cover of a vent assembly comprises an arm and a strut. The strut is connected with the cover at two positions that are spaced from one another. When the cover is in its closed position, a retention force is provided by the strut and distributed about the cover. The strut system includes a U-shaped strut to be coupled with a pair of brackets mounted on the cover. The arm includes a pronged receptacle to receive a leg of the U-shaped strut. Also, a pair of bearing blocks receive a web of the U-shaped strut to position the strut onto a base of the fan assembly.
According to a third aspect of the invention, a vent assembly comprises a base to be secured to an opening in a vehicle. A cover is hinged to the base. The cover has a rectangular configuration and is movable between an open and a closed position. A fan is optionally mounted for rotation in an opening in the base. A mechanism to raise and lower the cover between the open and closed position includes an arm associated with the base. The arm is coupled with a crank to initiate movement of the arm to raise and lower the arm. A strut is connected with the arm and with the cover. The strut is connected to the cover at two positions spaced from one another. When the cover is in a closed position, a retention force is provided by the strut and is distributed about the cover to retain the cover in a down position. The arm has an overall J-shape with a strut coupling mechanism at one end and a plurality of teeth at the other. The teeth are coupled with a screw mechanism of the crank to raise and lower the arm. The strut has an overall U-shape and is coupled with a pair of brackets mounted on the cover. The arm includes a pronged receptacle to receive a leg of the U-shaped strut. A pair of bearing blocks are positioned on the base to receive a web of the U-shaped strut to position the strut onto the base.
Further areas of applicability will become apparent from the provided description. 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 is a perspective view of a vent assembly with the cover in an open position.
FIG. 2 is a view like FIG. 1 with the cover in a closed position.
FIG. 3 is a side elevation view of the vent assembly in FIG. 1 .
FIG. 4 is a cross section view of the vent assembly in the open position.
FIG. 5 is a side elevation view like FIG. 3 with the cover in a closed position.
FIG. 6 is a cross section view of the vent assembly in the closed position.
DETAILED DESCRIPTION
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.
Turning to the figures, a vent assembly is illustrated and designated with the reference numeral 10 . The vent assembly 10 includes a base 12 and a cover 14 . A hinge 16 pivotally couples the cover 14 with the base 12 . Thus, the hinge 16 is secured to the cover 14 and either the base upper portion 20 or the deck 22 of the base 12 . The base 12 includes a lower portion 24 which is positioned through an aperture in a vehicle.
An optional fan assembly 26 , including a blade 28 and a motor 30 , is positioned in an opening 32 in the upper portion 20 of the base 12 . When the fan assembly is not included, the vent assembly is a static vent. The fan blade 28 rotates in the opening 32 to withdraw air out of or to deliver air into the interior of the vehicle.
A mechanism 40 is positioned on the base 12 to raise and lower the cover 14 from the base 12 . The raising and lowering mechanism 40 includes a strut 42 , arm 44 and crank 46 . The strut 42 has an overall U-shape as illustrated in FIG. 1 . The strut 42 includes a pair of legs 48 and 50 as well as a web 52 . Each leg includes an end 54 and 56 which projects parallel to the web 52 . The ends 54 and 56 include bushings 58 that ride in slots 60 of brackets 62 . The brackets 62 are secured to the cover 14 via fasteners. The web 52 of the strut 42 is secured into bearing blocks 64 . The bearing blocks 64 include a base 66 secured onto or integrally formed with the top portion 20 of the base 12 . The bearing block bases 66 include a channel 68 to receive the web 52 of the U-shaped strut 42 , as seen in FIGS. 1 and 4 . Also, covers 70 are positioned over the web 52 to secure the web 52 in the bearing block bases 66 onto the base 12 . Fasteners secure the covers 70 with their respective base 66 .
Accordingly, the U-shaped strut provides a connection at two positions on the cover 14 . When the cover 14 is in its closed position as illustrated in FIGS. 2 , 5 and 6 , the ends 54 , 56 of the U-shaped strut 42 extend beyond the mid point 72 of the fan base 12 . Also, the ends 54 , 56 of the struts 42 are spaced from the hinge 16 towards the side of the rectangular cover 14 opposing the hinge 16 . Thus, the strut 42 applies a retention force to maintain the cover onto the base 12 . Ordinarily, a seal 74 is positioned about the periphery of the upper portion 20 so that when the cover 14 is in its down position, the seal is contacted by the cover 14 as seen in FIG. 6 . This compresses the seal 74 to provide sealing of the cover 14 with the base 12 . By having the two point system, the force to retain the cover on the base 12 is distributed substantially equally on both sides of the cover 14 .
The arm 44 has an overall J-shape with a strut receiving receptacle 80 at one end and a plurality of teeth 82 at the other. The J-shaped body 84 of the arm is essentially a flat planar member. The teeth 82 are in the plane with the body 84 . The strut receiving receptacle 80 projects perpendicular to the body 84 . The receptacle 80 includes a pair of prongs 86 which receive the rod-shaped strut leg 50 of the strut 42 .
The tooth end of the arm body 84 includes an aperture 88 which receives a pin 90 to fix the arm 44 within the housing 92 . The housing 92 is opened at the top and includes a cylindrical portion 94 which receives a screw member 96 of the crank 46 . A handle 98 is secured to one end of the screw member 96 to enable rotation of the screw in the housing 92 .
The mechanism 40 lifts and lowers the cover 14 as follows. The handle 98 is rotated which, in turn, rotates the screw 96 . The screw 96 , in meshing contact with the teeth 82 , moves the cover 14 between positions. As the screw 96 rotates, the teeth 82 , move one direction or the other to open or close the cover 14 . As the teeth 82 are moved one way or the other, the body 84 pivots about the pin 90 . As this occurs, the arm receptacle 80 is moved up or down which, in turn, moves the strut 42 . As this occurs, the bushings 58 slide in the slots 60 of the brackets 62 which lift or lower the cover 14 . When the cover 14 is brought into its closed position, as illustrated in FIGS. 5 and 6 , the ends 54 and 56 of the strut 42 are past the center line 72 of the cover 14 . This provides an over center mechanism to compress the seal 74 positioned on top of the base upper portion 20 to seal the cover 14 with the base 12 . The U-shaped strut 42 provides a downward retention force on both sides of the fan via the brackets 62 . This downward force provides a distributed force about the cover 14 to maintain the cover 14 in contact with the base 12 in a closed position.
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. Such variations are not to be regarded as a departure from the spirit and scope of the invention. | A vent assembly has a base and a cover connected to the base. The cover moves between a closed and open position. A fan is optionally mounted for rotation in the base. A mechanism, including a strut system, raises and lowers the cover. The strut system is connected with the cover at two positions spaced from one another. When the cover is in its closed position, a retention force is provided by the strut system and is distributed about the cover. | 4 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of detecting circuit discontinuities in conductor members supported by glass sheets, such as in a defrosting automobile back light.
2. Description of the Technical Difficulties
Windows for automobiles, and particularly back lights, used for automobiles are commonly provided with electric heating elements for defrosting and defogging. Such back lights are generally made from a pattern cut flat glass sheet thermally bent or molded to fit the particular automobile window opening. Prior to the heating and bending of the glass sheet, a number of narrow spaced parallel lines of a conducting material is placed on the inside vision area of the glass. The parallel lines are connected on opposite adjacent margins thereof by a strip of electrodes of the same material which is generally a ceramic frit containing silver or silver oxide. Upon the heat of bending and tempering, the lines and strip electrode buses are fired onto the glass so that the pattern becomes part of the glass substrate. When the automobile electrical power source is connected to the strip electrode buses, the resultant resistant heating in the parallel strips defogs or defrosts the glass.
Normally the silver/silver oxide frit is applied by silk screening the pattern onto one surface of the glass sheet while it is still flat. During the subsequent treatment of the sheet by heating and bending the glass to the desired curvature, the frit material becomes tightly bonded to the glass surface.
Other glass sheets or substrates, such as aircraft transparencies have embedded in them a plurality of very fine conductor members, these being of copper or the like. The conductor members are of size, number, spacing and shape so as to not interfere with the transmission of light through the window and at the same time are such by the application of elecricity to suitable bus bars that it is possible to pass current through them and thereby heat the windshield for defogging or deicing.
Despite the manner in which the windshield or back light heating defrosting/defogging pattern is produced, it is likely that upon the manufacturing process, one or more breaks in the intended circuit pattern will occur. It is difficult to detect such breaks and is time consuming to view the piece of glass through a microscope so as to visually detect discontinuities.
One method of detecting the broken heater lines is described in U.S. Pat. No. 3,590,371 to Shaw. The Shaw patent teaches the use of detecting circuit discontinuities in glass sheets having conductor members embedded therein by placing in association with the glass a stratum of cholesteric-phase liquid-crystal material having appropriate color change temperature-range characteristics. The Shaw reference discloses passing current through the conductors and observing color changes in the vicinity of the operating conductors in the liquid crystal material. In practice, the Shaw invention includes a manual operation of placing a sheet of the temperature sensitive liquid crystal material over the inside surface of the horizontally positioned back light while power is applied to the heater grid. By observing the changing patterns in the liquid crystal material over a short period of time as the adjacent heater lines become hot by observing an ammeter in the power circuit the operator can tell which, if any, lines are broken and the amount of total current passing through the heater pattern. The operator after disconnecting the power and removing the liquid crystal sheets then records the observations manually.
Whereas the Shaw detection method produces good results in detecting discontinuities, due to the necessary manual operation it is not entirely suitable for an automatic detection system. Such an automatic detection system should be able to observe the broken or discontinuitous heater lines while the windshield or back light is passing through the manufacturing process. The detection system should not only record that a discontinuity has occurred but it should note the location and display the information so that the discontinuity can be repaired. It would be helpful if the method of detecting the discontinuity would not contact the glass, and would be capable of detecting the discontinuity as the glass part was moved underneath or would provide a movable probe over or under the heater lines so as to not produce marring or scratching. Further, it would be beneficial if such a testing inspection apparatus were provided that would be able to detect broken lines in silk screened pattern ceramic silver or silver oxide frit prior to being fused into the substrate as such a detecting means would enable the manufacturer to more conveniently repair discontinuitous lines prior to having those lines fused onto the glass substrate.
In 1879 E.H. Hall at John Hopkins University discovered that if a conductor while carring an electric field longitudinally was placed in a magnetic field with the conductor perpendicular to the direction of the field, that there was a difference of electric potential on either side of conductor. He also observed that if such points were joined through a sensitive galvanometer that a feeble current would be indicated. If such a Hall effect instrument is utilized in conjunction with a gaussmeter, the magnetic field surrounding a conducting material can be detected. The resulting device is known as a "Hall effect" probe.
SUMMARY OF THE INVENTION
The invention relates generally to a method and apparatus for detecting discontinuities in the conductor members in a defogging windshield or back light. The discontinuities in the conductor heated back light or similar substrate are detected by the use of a "Hall effect" magnetic field sensing probe which can detect the magnetic field associated with conducting member when the conducting member is conducting electricity. Accordingly, the invention provides a method of applying electric current to the conducting members and then scanning the heater lines with the "Hall effect" detection probe and observing the resultant magnetic field on each heater line. The lack of magnetic field associated with any heater line thus indicates a discontinuity. Not only can discontinuities be observed, but also anomolies wherein the width of a particular heater line is reduced or enlarged to the extent that it affects the magnetic field can be sensed by the "Hall effect" probe. In order to convert the magnetic field as sensed by the probe which produces a signal analagous to the magnetic field detected, it is necessary to condition the signal to convert the analog information into digital information. Accordingly, the invention includes the "Hall effect" sensing probe and an amplifier to amplify the analog signals so produced. Signal conditioning circuitry is provided to condition the analog signal and convert it to a digital signal to be processed by a microprocessor and then displayed. The display could be in the form of readily observable light emitting diodes (LEDs) which would be activated upon the presence and detection of a broken heater line. The display could also include a digital readout of the relative amplitude of the observed magnetic field and it could also include the amount of power applied to the heater pattern itself. The display could thus be a standard liquid crystal display or it could be a printed readout for producing labels which could then be placed on the glass and thus indicating the total "Hall effect" inspection.
In order to fully automate the method of detecting discontinuities, a glass edge sheet detection means is employed which then determines the distance from the glass edge to the first heater line in order to anticipate where magnetic field should be observed. Accurate clocking means and stepping motor is provided to determine the accurate positioning of the probe with respect to the heater lines. In order to keep the probe off the glass and the heater lines itself, the apparatus includes a wheel which suspends the probe from the glass and a bridge mechanism which can move the probe with respect to the glass while the glass is stationary and in a horizontal orientation. The wheel is only used to suspend the probe above the glass. It is also contemplated within the scope of the invention that upon the detection of a broken heater line that an alarm would be sounded when a discontinuity is observed so that that particular back light or windshield could be removed from the line for repair.
By the use of the instant invention a wide variety of heater line patterns could be manufactured in which the detection is automatic thus allowing for high volume production as well as also allowing batch production. The manual labor associated with prior art placing liquid crystal substrates over the glass is considerably reduced.
In order that the invention may be more clearly understood, there are the preferred embodiments of the invention which will now be described in reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatical depiction of the invention for detecting discontinuities in heater back light pattern lines showing a "Hall effect" probe utilized in conjunction with a heater back light grid on a sheet of glass in which the grid is connected to a power supply.
FIG. 2 is a right side perspective view of the sensing probe and movement mechanism to provide relative movement between the depicted glass sheet and the "Hall effect" probe.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The apparatus 10 is shown generally in FIG. 1 in diagrammatic form in which a glass sheet 11 having heater lines 12 and bus bar 13 is connected at connection points 14 to power supply 15. The connection leads 16 and 17 complete a circuit between the power supply and the defogging heater lines 12. Ammeter 18 is placed between leads 16 and 17. The power supply provides a direct current which delivers a current as recorded by ammeter 18 appropriate for the particular pattern of heater lines 12 as defined by the automobile manufacturer who designed the heated back light 11. Heated back light 11 is a tempered glass sheet having ceramic silver or silver oxide frit pattern silk screened on the sheet 11 so as to produce bus bars 13 and heater lines 12 in an appropriate pattern. When the sheet 11 is heated to be bent and formed into the pattern, the silver or silver oxide frit is fused into the substrate of the glass. The instant invention can be utilized to detect broken heater lines prior to the time that the glass sheet 11 is tempered, however in the preferred embodiment the detection of broken heater lines is accomplished after the part has been bent, tempered and the pattern including bus bars 13 and lines 12 have been fused onto the glass sheet 11. The instant invention allows for detection of broken heater lines 13 without actually contacting the glass surface 19 and would work whether the heater lines 12 were placed on either side of the glass.
In the preferred embodiment as depicted in FIG. 2, heater lines 12 are shown on the upper surface 19 of glass sheet 11 and the "Hall effect" probe 21 is suspended above glass surface 19 by use of suspension wheel 22. Suspension wheel 22 is provided with a rubber non-marring contacting surface 23. The purpose of having contact with glass surface 19 by wheel 22 is to maintain a constant distance above heater lines 12 as Hall effect probe 21 is moved across heater lines 12.
With reference to FIG. 1, it can be seen that "Hall effect" Probe 21 is provided with "Hall effect" probe tip 24 which is suspended above heater lines 12 in glass sheet 11. The "Hall effect" probe 21 is electrically connected to conditioning circuitry which includes circuits which will amplify the analog signals detected by "Hall effect" probe 21. The conditioning circuitry further includes electrical filters well known in the art as well as circuitry for producing a digital signal by squaring the analog signals produced by the "Hall effect" probe 21. "Hall effect" probe 21 is a probe which is commercially available from various suppliers. Conditioning circuitry 25 which produces a digital output signal such as the square wave is then operably connected to a microprocessor or computer which is capable of processing the digital signal to display the continuity information of the back light heater lines 12 as the "Hall effect" probe 21 is moved relative to glass sheet 11. Microprocessor 26 could be any commercial microprocessor, however it has been found that the Motorola 6800 Microprocessor provides acceptable results. The microprocessor 26 not only can provide a display of the magnetic field surrounding each heater back light as the "Hall effect" probe 21 passes over it also, it is capable of sounding an alarm 28 when the probe passes over a position where a magnetic field should be. In order to provide such an alarm information, it is necessary to know the glass movement distance with respect to the "Hall effect" probe 21 and have preprogrammed the position of expected magnetic fields that relate to individual lines. Such a distance input to microprocessor 26 is provided by the use of a stepping motor 29 and associated circuitry.
It can be shown in FIG. 2 that stepping motor 29 will accurately measure relative travel between glass sheet 11 and Hall effect probe tip 24. In FIG. 2 it can also be seen in the preferred embodiment that a bridge 31 utilizing a screw shaft 32 and shafting 33 allows the "Hall effect" probe 21 to move in the direction of travel of relative motion between glass sheet 11 and "Hall effect" probe 21. Vertical movement is allowed by vertical slide 34 which is connected to compliancy slide 36. The pressure exerted against the glass by wheel 22 can be controlled by use of screw mechanism 37 which applies a biasing force to a spring in compliance to slide 36 thereby adjusting the amount of pressure against glass surface 12 so as not to mar the glass surface or to scratch heater lines 12 and to inspect curved glass.
In the preferred embodiment, the glass sheet 11 is held stationary and the "Hall effect" probe head is also provided with an optical scanner 41 which detects the edge 25 of glass sheet 11. The bridge 31 thus suspends the optical scanner 41 as well as "Hall effect" probe 21 having "Hall effect" probe tip 24 above the back light 11 being checked. As the steppig motor drives the "Hall effect" probe 21 along and above the back light heater lines, the optical sensor 41 signals microprocessor 26 when the optical scanner 41 is over the glass surface 19 and the Hall Effect probe 21 which is also non-contacting signals microprocessor 26 each time that probe tip 24 has passed through a magnetic field created by an electric current passing through a heater line 12. During this time pulses driving the stepping motor 29 are sent to the microprocessor 26 which thus provides a movement distance clock to signal the program logic in microprocessor 26. The signals received from optical scanner 41 are processed through conditioning scanning circuitry 42 prior to being inputted into microprocessor 26.
It has been found that if the instant invention 10 is placed on a conveyor or other automatic movement mechanisms, that additional inputs into the microprocessor 26 such as "initial set up", "run automatic", and "stop alarm" are also beneficial in that by use of such inputs and logic in the program for the microprocessor 26 that the microprocessor 26 can therefore control the movement of the motor both forward and reverse direction as well as to adquately provide for displays representing that the inspection is complete as well as producing an alarm or LED or other display representing a heater line 12 having a discontinuity.
It is perceived that the instant invention 10 could be placed upon an industrial robot (not shown) which would thereby move optical scanner 41 and "Hall effect" probe 21 over the surface of the glass 19 including heater lines 12 to detect any discontinuities. The invention contemplates relative movement between "Hall effect" probe 21 and heater lines 12. The relative movement could be provided by moving the probe 21 or by moving the heater lines 12 or by movement of both.
As can be appreciated from the foregoing description of the preferred embodiment, the invention is not limited to the above example which is presented for illustration purposes only. It is understood that other steps, examples, components, and methods of operation would occur to those skilled in the art from a thorough reading of this disclosure without departing from the scope of the invention as claimed hereinafter. | A method and apparatus for detecting discontinuities in electric conductor heating lines in automobile heated back lights is disclosed. The apparatus includes a "Hall effect" probe, a microprocessor, a display, a stepping motor drive, an optical scanner and associated circuitry. The method includes the steps of energizing the heating grid and moving a Hall effect probe in the vicinity of each conductor line. Any heater line having discontinuity will lack a detectable magnetic field. | 6 |
BACKGROUND OF THE INVENTION
The invention concerns a clasp with protruding element for jewellery items, such as bracelets, straps, necklaces and alike, particularly suitable for application on watch bracelets. It is known that to wear watches on the wrist bracelets and straps made of gold and other precious alloys are used, the ends of which are reciprocally connected by means of appropriate clasps.
The clasps that are applied to said bracelets or straps must ensure proper fastening, but above all they must ensure easy opening and clasping, considering that the person carrying out these operations can use one hand only.
The clasp object of the present invention aims at achieving these purposes.
SUMMARY OF THE INVENTION
In particular, one of the goals of the invention is the implementation of a clasp that should ensure the stable connection of the strap or bracelet ends and prevent any accidental opening.
Another aim of the invention is the implementation of a clasp that should be easy to open and fasten with one hand only, so that the watch can be comfortably put on and taken off.
The above mentioned goals are achieved through the implementation of a clasp for jewellery items, such as watch straps, bracelets, necklaces and similar ornamental items, which, according to the main claim, comprises a female element provided with first means for the connection to one end of one of said ornamental items and with a hole suitable for housing a protruding element belonging to a male element provided with second connection means for the connection to the other end of the same ornamental item, and wherein said protruding element is provided with a pair of radially protruding coupling elements, each one of which is positioned at one end of a pair of shaped rods cooperating with operating means suitable for achieving the caliper-like movement of said rods around a pin by means of which they are rotatingly connected to each other and to the body of said male element, said caliper-like movement being suitable for achieving the connection or the disconnection of said coupling elements to/from corresponding check elements belonging to said female element when said protruding element is connected or disconnected in or from said hole provided in said female element.
According to a possible application of the invention, said operating means suitable for achieving the caliper-like movement of said shaped rods comprise a pair of pin buttons protruding from the body of said male element, which are operated through the pressured exerted by two opposite fingers, in such a way as to push the coupling elements within the outline of the body of the protruding element and to separate the male element from the female element and unfasten the clasp.
The operating means that, instead, intervene after the male element and the female element have been coupled, comprise a cylindrical spring interposed between said shaped rods beyond the reciprocal hinging point; the thrusting force of the spring, after the insertion of the protruding element into the hole of the female element, achieves the fixing of the coupling elements in the check elements provided in the female element, in such a way as to ensure the proper fastening of the clasp.
As an alternative, the cylindrical spring can be replaced with a cylindrical spring with protruding ends, positioned coaxially to the connection pin between the shaped rods.
To advantage, the clasp object of the invention is easy to use and can be fastened or opened through the opposing pressure exerted by two fingers, which makes it easier and quicker to put on and take off the bracelet.
BRIEF DESCRIPTION OF THE INVENTION
The above mentioned goals and advantages will be better highlighted in the description of a favourite application of the invention in question, illustrated in the attached drawings, wherein:
FIG. 1 is an axonometric view of the clasp object of the invention with the male and female elements that make it up disconnected,
FIGS. 2 and 3 are front views of the two shaped rods that make up the clasp object of the invention, each one provided with the relevant operating pin;
FIG. 4 is a side view of the two shaped rods of FIGS. 2 and 3, with the interposed spring that makes them reciprocally elastic;
FIG. 5 shows a longitudinal section of the male and female elements that make up the clasp disconnected;
FIG. 6 shows a longitudinal section of the male and female elements that make up the clasp object of the invention at the beginning of the coupling phase;
FIG. 7 shows a longitudinal section of the male and female elements that make up the clasp object of the invention during the coupling phase;
FIG. 8 shows a longitudinal section of the male and female elements that make up the clasp object of the invention after the coupling;
FIG. 9 shows a longitudinal section of a variant of the clasp object of the invention.
DESCRIPTION OF THE INVENTION
As shown in FIG. 1, the clasp object of the invention, indicated as a whole by 1, comprises a female element, indicated as a whole by 2, provided with first connection means 3 at one end (not represented) of an ornamental item, for example a bracelet or a necklace, and a male element, indicated as a whole by 5, provided with second connection means 6 at the other end (not represented) of the same ornamental item.
Said male element, as shown in detail in FIGS. 5 to 8, comprises a substantially cylindrical protruding element 7, provided with two slots 8, through each one of which a coupling element 9 protrudes, said coupling element being suitable for fitting into a corresponding check element 71 provided inside said female element 2.
In particular, it can be observed that each coupling element belongs to a shaped rod 12 and said shaped rods are rotatingly connected to each other and to the body 13 of said male element by means of a pin 14.
Furthermore, as shown in detail in FIGS. 2 to 4, said shaped rods are provided with operating means that comprise:
a pair of pin buttons 20, protruding from the body of said male element, each one of which is rotatingly hinged to a corresponding shaped rod by means of a pin 21, in intermediate position with respect to the shaped rod, between the pin connecting said rods with each other and the end opposite the end where said coupling elements are provided;
a cylindrical spring 50 interposed between said shaped rods and coaxial to said pin, whose ends rest against each one of said rods.
As an alternative to the use of the cylindrical spring positioned coaxially to said pin, according to a different application of the invention represented in FIG. 9, a cylindrical spring having the same effect as the spring 22 can be interposed between the ends of said shaped rods arranged opposite the end where said coupling elements are provided. In both the above mentioned applications, the two shaped rods can reciprocally rotate according to a caliper-like movement around the pin when they are subjected to the action of said operating means. More particularly, when said pin buttons are pressed by means of two opposite forces, they get within the outline of the body of the male element and make the shaped rods rotate like a caliper; in turn, the shaped rods push the coupling elements within the outline of the body of the protruding element.
At the same time, the approach of the pin buttons produces tension on the spring, so that when the action exerted by the opposite forces on said pin buttons stops, the elastic recovery of the cylindrical spring causes again the caliper-like rotation of said shaped rods around the same pin, which once again makes the coupling elements protrude through the slots of the protruding element.
Thanks to the presence of the pins connecting each sliding pin to the corresponding shaped rod, said pin buttons get in the body of the male element keeping their axis 210 substantially orthogonal to the longitudinal axis 30 of the clasp, in such a way as not to interfere with the body of the said male element.
As far as each coupling element is concerned, it can be observed that it substantially comprises a tooth shaped like an asymmetrical spire defined by two sides:
a front side 92 shaped with convex profile that, as shown in FIG. 6, during the coupling of the elements constituting the clasp rests against the female element and causes the caliper-like rotation of both the shaped rods, thus making the coupling elements get into the slots to ensure the insertion of the protruding element into the hole 20 of the female element;
a rear side 93 that, together with the body of said shaped rod, defines an undercut area 94 suitable for housing one of the check elements of said female element in order to prevent the separation of the male and female elements, 5 and 2 respectively, after the coupling has taken place.
As far as said check elements are concerned, it can be observed that each one of them is constituted by a radial protrusion having a triangular profile with acute angle 100 directed towards the inside of the female element and defined by the side surface of said hole 70 provided in the said female element and by a second side 101 that is inclined with respect to said side surface of said hole.
In a different, not represented application of the invention, said check elements, which in the application described herein are two, each one positioned in correspondence with a coupling element , can be continuous, in fact they can be constituted by an annular area with acute angle directed towards the inside of the female element.
Starting from the situation in which the clasp is open, that is, with the male and female elements that make it up separated from each other, as shown in FIG. 5, the male element is forced against the female element with an axial movement according to the direction 40, so that, as already explained, the convex profile of the front side 92 of each coupling element causes the rotation of the shaped rods around the pin and the coupling elements are pressed within the outline of the protruding element, which, as shown in FIG. 7, is slided into the hole of the female element.
After the coupling has taken place, the elastic recovery of the cylindrical spring 50 or 22--according to the chosen application--which had previously been compressed, makes the coupling elements protrude from the slots again and fit into the check elements, thus keeping the male and female elements stably connected and fastening the clasp.
As an alternative, the coupling of the male element with the female element can be achieved by pushing the coupling elements within the outline of the protruding element through the application of opposite pressures on the pin buttons with two fingers.
To open the clasp and separate the male and female elements that make it up, it is sufficient to apply a pressure 23 in opposite directions to the pin buttons, in such a way as to produce again the caliper-like rotation of the shaped rods and push the coupling elements within the outline of the protruding element, thus releasing them from the check elements. The protruding element can thus be withdrawn from the hole by separating the male and female elements through a relative axial shift of the male element or of the female element.
According to the above description, the clasp object of the invention achieves the set goals.
In particular, the invention achieves the goal to implement a particularly safe clasp, since, as already explained, to separate the elements that make it up it is necessary to apply a pressure in opposite directions 25 onto the pin buttons of the male element and at the same time to reciprocally separate the male element and the female element.
It has also been demonstrated that the clasp object of the invention is particularly suitable for application on bracelets, in particular watch bracelets, since its opening and fastening can be obtained by using the fingers of one hand only.
Obviously, the clasp can have any shape and size, and likewise the elements that make it up can have any profile, size and shape.
Any variant of the clasp is to be considered as protected by the present invention, provided that it is based on the same innovative concept described herein. | The invention is a clasp for jewellery items comprising a female element suitable for housing a protruding element belonging to a male element. Said protruding element is provided with a pair of coupling elements, each one positioned at one end of a pair of shaped rods cooperating with operating means suitable for achieving the caliper-like movement of said rods around a pin that connects them to each other and to the body of said male element in order to obtain the connection or the disconnection of said coupling elements to or from corresponding check elements belonging to said female element. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates to the field of chemical engineering and technology, In particular relates to the sub-field of synthesis of high quality alternative liquid engine fuel from non-petroleum based feedstock, more particularly relates to a method for regulating and optimizing the synthetic process of polyoxymethylene dimethyl ethers utilizing chemical thermodynamic principle.
BACKGROUND OF THE INVENTION
[0002] Recent investigation shows that, the apparent consumption of diesel fuel in China has already mounted up to 167 million tons, which leads to frequent occurrence of short supply of diesel fuel (the domestic demand ratio of diesel fuel to petrol is about 2.5:1, but the production ratio is about 2.3:1). Besides the reasons of unreasonable pricing of different types of oil products, and slow price linkage mechanism of domestic petroleum products with international crude oil, the fundamental reason is the restriction of resource shortage. Traditionally, diesel fuel is made from petroleum based feedstock, and the resource endowment of China characterized in relatively “rich in coal, poor in oil, and lack in gas” leads to increasingly prominent contradiction between petroleum supply and relatively fast sustainable development of economic society. Since China became a net importer of petroleum in 1993, the import quantum increases fast and constantly, and the foreign-trade dependence already exceeded 56% after 2011, it has a severe impact on national strategic security of energy.
[0003] Furthermore, the worsening crude oil quality leads to continuous scale expansion of domestic catalytic processing of heavy oil and increasing percentage of diesel fuel produced by catalytic processing, which results in gradual decline of the cetane number (CN value) of diesel fuel products and significant increase of noxious substance discharged after combustion, therefore, the urgent problem to be solved is to improve the CN value of diesel fuel.
[0004] The tail gas discharged by diesel engine contains, besides CO, CO2 and NOx, a large amount of noxious substance such as unburned hydrocarbon compounds (HC) and particulate matter (PM), which is one of the main sources of PM2.5 contamination in urban air. International Agency for Research on Cancer (IARC) affiliated with World Health Organization (WHO) declared in June, 2012 the decision to promote the cancer hazard ranking of diesel engine tail gas, from “possibly carcinogenic” classified in 1988 to “definitely carcinogenic”. As scientific research advances, now there is enough evidence to prove that diesel engine tail gas is one of the reasons that cause people to suffer from lung cancer. Furthermore, there is also limited evidence indicating that, inhaling diesel engine tail gas is relevant to suffering from bladder cancer. IARC hopes that this reclassification can provide reference for national governments and other decision makers, so as to actuate them to establish more strict discharge standards of diesel engine tail gas. This significant decision undoubtedly puts forward more rigorous requirements of diesel fuel quality.
[0005] Reducing the content of noxious substance such as sulfur, nitrogen and aromatic hydrocarbon in fuels by petroleum refining process such as hydrofining is an effective technical route to improve fuel quality, but has very demanding requirements of hydrogenation catalyst and reaction process, with relatively high processing cost. Internationally, many scientific research institutes are carrying out research and development on production technologies of oxygen-containing blending components of petrol and diesel fuel, especially those diesel fuel blending components with high oxygen and high cetane number, and this has recently become a research hotspot in the technical field of new energy.
[0006] Polyoxymethylene dimethyl ethers (also known as polymethoxymethylal, dimethyl-polyformal, with the general formla of CH 3 (OCH 2 ) n OCH 3 , abbreviated as DMM n , n=8), which is a yellow liquid with a high boiling point, an average cetane number reaching above 76, and increasing dramatically with the increase of its degree of polymerization, an average oxygen content of 47%-50%, a flashing point of about 65.5° C., and a boiling point of about 160-280° C., is a clean diesel fuel blending component with a high cetane number. When blending into ordinary diesel by a certain percentage (e.g., 15 v %), it can significantly increase oxygen content of diesel fuel products, so as to promote sufficient combustion of diesel fuel and to sharply reduce the discharge of combustion-generated pollutants such as NO x , CO and PM, without the need to make any modification in the fuel supply system of the engine. Furthermore, as polyoxymethylene dimethyl ethers added into ordinary diesel cause the diesel to be diluted, accordingly, the contents of aromatic compounds and sulfides in the diesel fuel products are also reduced.
[0007] Synthesis of polyoxymethylene dimethyl ethers may be carried out by processing synthesis gas through a series of steps of methanol, formaldehyde, methylal, and polyformaldehyde etc. The verified coal reserves in China are about 714 billion tons, and developing coal-based methanol industry has huge resource advantages. However, the problem of excessive production capacity of methanol is particularly prominent in recent years. For example, the production capacity of methanol broke through 50 million tons in 2012, but the rate of equipment operation is merely about 50%. Thus the industrial chain of coal chemical industry is in an urgent need to be further extended. Therefore, developing a technologically advanced and economically rational industrial process for synthesizing polyoxymethylene dimethyl ethers based on methanol as upstream feedstock can not only provide a new technology to significantly improve diesel fuel product quality, but also improve the feedstock structure of diesel fuel production, so as to make it more suitable for the resource endowment of domestic fossil energy and enhance the strategic security of domestic supply of liquid fuel for engines.
[0008] In the aspect of synthesis of polyoxymethylene dimethyl ethers, a lot of work has been done at home and abroad, regarding research and development of methods for synthesizing polyoxymethylene dimethyl ether products where n=1−10 by using methanol, methylal, lower alcohol, aqueous formaldehyde solution, paraformaldehyde, etc. as feedstock, in the presence of acidic catalysts.
[0009] In various kinds of feedstock route, more research has been done about the synthesis of polyoxymethylene dimethyl ethers from trioxane or paraformaldehyde and methylal, which includes:
[0010] U.S. Patent US2007/0260094 A1 discloses a preparation process of polyoxymethylene dimethyl ether using methylal and trioxane as feedstock in the presence of acidic catalyst. The water contained in the reaction mixture of methylal, trioxane and acidic catalyst should not exceed 1%. Polyoxymethylene dimethyl ether where n=3 and 4 in the reaction product is separated by rectification, and methylal, trioxane and polyoxymethylene dimethyl ethers with degree of polymerization of n<3, and some n>4 can be recycled.
[0011] A process of catalytic synthesis of polyoxymethylene dimethyl ether with degree of polymerization of methoxy groups at 2-10, by using methylal and trioxane as feedstock, in the presence of homogeneous or heterogeneous acidic catalysts such as liquid mineral acids, sulfonic acids, heteropolyacids, acidic ion-exchange resin, zeolite, etc. at the pressure of 1-20 bar and the reaction temperature of 50° C.-200° C. and under strictly limited condition of the water content introduced into the system, is disclosed in Chinese patent literature CN101048357A of BASF Aktiengesellschaft. By optimization, polyoxymethylene dimethyl ether with degree of polymerization of methoxy groups at 3 and 4 can be separated by distillation through three towers.
[0012] Tianjin University discloses a process of synthesis of polyoxymethylene dimethyl ether using methylal and trioxane as feedstock in Chinese patent literature CU102432441A, which uses cation exchange resin as a catalyst in the fixed bed reactor, under the reaction condition of the temperature of 80° -150° C., the pressure of 0.6 MPa-4.0 MPa and nitrogen atmosphere, and in the main products obtained, n is 3 or 4.
[0013] Furthermore, in recent years abroad, Jakob Burger etc, [i.e., Fuel 89 (2010) 3315-3319] synthesized DMM n using ion-exchange resin as a catalyst and methylal and trioxane as feedstock in a stirred-tank reactor in laboratory by intermittent operation, which focuses on studying the relationship between the equilibrium composition and reaction temperature, feedstock mass ratio. In China, some colleges and universities such as East China University of Technology, Nanjing University, Lanzhou University of Technology etc. are carrying out some basic and applied basic research in the aspect of chemical thermodynamics, catalyst screening and reaction process.
[0014] In conclusion, there has already been lots of research about preparing target product DMM n using methylal and paraformaldehyde or trioxane as feedstock, the catalysts involved cover almost all the major types of acidic catalysts, but in the implementation process, no matter what kind of catalyst and reactor are used, the rate of chemical reaction is always very low, and the reaction is generally required to last for hours or even longer, it has become a major challenge which limits large-scale industrialization of this technology.
SUMMARY OF THE INVENTION
[0015] The technical problem to be solved by the present invention is, to provide a synthetic process of higher chemical reaction rate, higher one-way yield of target product, high selectivity of target products with higher degree of polymerization of methoxy groups.
[0016] A method for synthesizing polyoxymethylene dimethyl ethers is provided in the present invention, the synthesis reaction is carried out by using paraformaldehyde or trioxane and methylal as feedstock in the presence of acidic catalyst, the initial temperature of reaction is controlled at 100-120° C., then the temperature is reduced to 50-70° C. by successive stepwise cooling or programmed cooling, the reaction pressure is controlled at 0.1-4.0 MPa, and the molar ratio of paraformaldehyde or trioxane metered in formaldehyde units to methylal in the feedstock is 1.5:1-8:1.
[0017] The manner of successive stepwise cooling of the reaction mixture is that the temperature is reduced by 10-20° C. for each step, and then isothermal reaction is carried out, preferably the range of temperature reduced for each step is 10-15° C.
[0018] All kinds of acidic catalysts in prior art which can implement the synthesis of polyoxymethylene dimethyl ethers can be used as the catalyst of the present invention, preferably a strong acidic cation exchange resin, and currently strong acidic cation exchange resin commercially available can achieve the objective of the present invention.
[0019] The amount of the catalyst is equal to 0.3-3 wt % of the total amount of the feedstock, and preferably the amount of the catalyst is equal to 2-3 wt % of the total amount of the feedstock.
[0020] The molar ratio of paraformaldehyde or trioxane metered in formaldehyde units to methylal in the feedstock is 1.5:1-6:1, and preferably 1.5;1-2:1.
[0021] Preferably the pressure is controlled at 1.0-4 MPa, and more preferably 2-3 MPa.
[0022] The reaction time of the synthesis reaction is 2-10 hours, and preferably 4-10 hours.
[0023] As an implementable way, the synthesis reaction is carried out in a single-stage tank reactor using batch operation, and successive stepwise cooling according to time in the reaction process is achieved by a programmed temperature control system.
[0024] As an alternative way, the synthesis reaction is carried out in multi-stage tank reactors connected in series using continuous operation, and successive stepwise cooling in the continuous reaction process is achieved by controlling temperatures of each respective reactor to be different.
[0025] Further, the number of the multi-stage tank reactors connected in series is 2-8.
[0026] More preferably, the tank reactor is slurry bed reactor.
[0027] The present invention further discloses polyoxymethylene dimethyl ethers synthesized by the above-mentioned method.
[0028] The reaction equation of the process of the present invention is as follow:
[0000] CH 3 O(CH 2 O) n-1 CH 3 +HCHO 13 <=>_CH 3 O(CH 2 O) n CH 3 +Q n-1
[0029] where n is degree of polymerization of methoxy groups, and n≧2; Q 1 is the quantity of released heat of the i th main reaction, and i=n−1.
[0030] Because synthesizing DMM n using trioxane or paraformaldehyde and methylal as feedstock is a highly exothermic reversible reaction. It is found in research that the relationship between the equilibrium constant of the reaction and the temperature is significantly dependent on the type of feedstock and polymerization degree of methoxy groups in the reaction product. And from the perspective of structural characteristics of the reaction network of the study, the degree of polymerization of methoxy groups in product increases sequentially, and the activity of all kinds of catalysts used so far is generally lower, the rate of reaction is slower. Similarly in view of the above understanding based on thermodynamics of the reaction system itself, the reaction network structure and dynamic characteristics, further taking into account that, when using certain feedstock systems, the target product will be synthesized while notable amount of water will be produced, so as to increase the investment and energy consumption of the post-separation, within the practicable temperature range of the reaction, the equilibrium constant of the synthetic reaction is sensitive to temperature variation, and the level of sensitivity will increase with the increase of degree of polymerization of methoxy groups in product. Based on these understanding of thermodynamic property of the reaction system, the present invention puts forward to use a specially designed slurry bed reactor system under the conditions of eliminating diffusion effects and suitable temperature and pressure to achieve the synthetic reaction.
[0031] For the slurry bed reactors of batch operation, for example, a single-stage slurry bed tank reactor of batch operation, successive stepwise cooling or programmed cooling is used; for the slurry bed reactors of continuous operation, including multi-stage slurry bed tank reactors connected in series, tubular slurry bed reactors, tower-type slurry bed tank reactors and static hybrid-type slurry bed tank reactors etc., the way used is that the spatial distribution of the reaction temperature is optimized, for example, for multi-stage slurry bed tank reactors connected in series of continuous operation, the reaction temperature is reduced by progressively stepwise cooling, so as to repeatedly and duly break through the limitation of thermodynamic equilibrium of the chemical reaction, to increase the average rate of chemical reaction, one-way conversion rate of the feedstock, and the overall one-way yield of the target product, at the same time, to improve the selectivity of target product with suitable degree of polymerization of methoxy groups, so as to strengthen the reaction process.
[0032] The aforementioned technical solutions of the present invention have the following advantages, as compared to the prior art:
[0033] 1. For the feedstock system of paraformaldehyde or trioxane and methylal and within suitable operating temperature range of the selected catalyst, in consideration of the characteristic that the equilibrium constant of the synthetic reaction is sensitive to temperature variation and the level of sensitivity will increase with the increase of degree of polymerization of methoxy groups in product, the synthetic process by stepwise cooing is designed in the manner of reaction→being close to chemical equilibrium→cooling to make the equilibrium shift in the direction in favor of producing target product→reacting again, so as to repeatedly and duly break through the limitation of chemical reaction equilibrium, to promote continuously forward reaction, to increase the average rate of chemical reaction, one-way conversion rate of the feedstock, and the overall one-way yield of the target product, especially to improve the selectivity of target product with suitable degree of polymerization of methoxy groups, so as to strengthen the reaction process; compared to the method of maintaining a constant reaction temperature all the time, higher overall yield of the target product can be achieved in the same reaction time, and selectivity of products with higher degree of polymerization of methoxy groups can be increased;
[0034] 2. The technical solution can be achieved by using the slurry bed tank reactor of single batch operation, through successive stepwise cooling according to time by a programmed temperature control system, and it also can be achieved by using multi-stage slurry bed tank reactors connected in series of continuous operation, through successive stepwise cooling in the continuous reaction process by controlling temperatures of each respective reactor to be different, which is easy to do.
[0035] 3. The reaction technical ideas provided by the present invention can easily be extended to other types of continuous-operation reactors in which DMM n is synthesized by using paraformaldehyde or trioxane and methylal as feedstock, in the presence of acidic catalyst;
[0036] 4. The method of the present invention can effectively shorten the reaction time, improve one-way yield of the product, and no water is produced in the whole system, and subsequent extraction and refinement process is relatively simple.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] In order to make the present invention clearly understood more easily, detailed description is further presented below, in accordance with specific embodiments and in conjunction with accompany drawings, wherein,
[0038] FIG. 1 is a kind of process flow diagram showing the synthetic process of the present invention;
[0039] FIG. 2 is another kind of process flow diagram showing the synthetic process of the present invention;
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0040] All kinds of strong acidic cation exchange resin catalyst known in the prior art can be selected and used as the catalyst in the technical solution of the present invention, in the following embodiments, D001 macroporous strong acidic styrene type cation exchange resin and 001×7 strong acidic styrene type cation exchange resin produced by Shanghai Jin Kai Resin Co., Ltd (Shanghai resin factory) are taken as examples to expound the technical effect.
Embodiment 1
[0041] Experimental device of the process flow of this embodiment is shown in FIG. 1 . The feedstock solution of paraformaldehyde and methylal is prepared according to a 2:1 molar ratio of paraformaldehyde metered in formaldehyde units to methylal, the solution is added into a 0.3 L single-stage stirred tank reactor, and then D001macroporous strong acidic styrene type cation exchange resin catalyst at the amount of 2 wt % of the overall feedstock is added. The initial pressure of the reaction is controlled at 2.0 MPa, and stirring speed is 250 r/min. And the isothermal reaction experiment using stepwise programmed cooling is carried out in accordance with the following procedures; the reaction mixture is rapidly heated to 100° C., after that the isothermal reaction is carried out for 4 hours; the reaction temperature is rapidly cooled to 90° C. in very short time, then the isothermal reaction is carried out for 2 hours again; the reaction temperature is rapidly cooled to 80° C. in a few minutes, then the isothermal reaction is carried out for 2 hours again; the reaction temperature is rapidly cooled to 70° C. in a few minutes, then the isothermal reaction is carried out for 2 hours again, until the reaction is completed. The sampling is started from when the reaction temperature reaches 100° C. and the timing is started, thereafter samples are taken once per hour for analysis of product composition.
[0042] The overall yield of the target product after 10 hours of reaction is 58.74 wt. %. It is also found that after 5 hours the concentration of DMM 8 in the product has reached about 0.3 wt %.
Embodiment 2
[0043] The process flow of this embodiment is the same as Embodiment 1. The reaction feedstock and conditions of this embodiment are similar to Embodiment 1, and the difference is that the reaction temperature is controlled at 100° C. all the time, after 10 hours the reaction is completed. The final overall yield of the target product is 51.66 wt %, DMM 8 is not detected throughout the reaction.
[0044] The concentration distribution of final products in Embodiment 1 and Embodiment 2 is shown in the following table.
[0000]
Serial number
DMM 2
DMM 3
DMM 4
DMM 5-8
DMM n>8
Embodiment 1
25.45 wt. %
15.12
8.73
9.44
~0
wt. %
wt. %
wt. %
Embodiment 2
22.98 wt. %
13.72
7.33
7.63
~0
wt. %
wt. %
wt. %
[0045] As can be seen by analyzing the table, after the same reaction time of 10 hours, the operation scheme of successive stepwise cooling is compared with the isothermal reaction in which the temperature is kept at the initial temperature of the aforementioned successive cooling, and it is found that the concentration of each kind of the target product of the former is higher than the latter, the overall yield of ΣDMM 2-8 is increased by about 7 percentage points, the proportion of DMM 5-8 in the target product is also higher. It is clearly indicated that successive cooling indeed promote the equilibrium of the reaction system to shift in the direction of producing the target product, and it can not only increase the one-way overall yield of the target product, but also improve the selectivity of target products with higher degree of polymerization of methoxy groups, thus strengthen the synthesis reaction.
Embodiment 3
[0046] Experimental device of the process flow of this embodiment is shown in FIG. 2 . The feedstock solution is prepared according to a 2:1 molar ratio of paraformaldehyde metered in formaldehyde units to methylal, the solution is added into a three-stage combination of 5.0 L slurry bed tank reactors connected in series, the temperature of the first reactor, the second reactor and the third reactor is respectively controlled at 100° C., 80° C. and 60° C., with continuous feeding, and the average reaction time of each tank reactor is kept at about 2 hours. The type of catalyst and its amount used and other reaction conditions are the same to Embodiment 1. The operation is carried out continuously until the system is stable and samples are taken for composition analysis. The final overall yield of the target product is ΣDMM 2-8 =57.22 wt. %. DMM 8 is detected in the final product.
Embodiment 4
[0047] The process flow is shown in FIG. 2 . The feedstock solution is prepared according to a 2:1 molar ratio of paraformaldehyde metered in formaldehyde units to methylal, the solution is added into a three-stage combination of 5.0L slurry bed tank reactors connected in series, the temperature of the first reactor, the second reactor and the third reactor is all controlled at 100° C, with continuous feeding, and the average reaction time of each tank reactor is kept at about 2 hours until the constant state is reached. The type of catalyst and its amount used and other reaction conditions are all the same to Embodiment 3. The operation is carried out continuously until the system is stable and samples are taken for composition analysis. The final overall yield of the target product is ΣDMM 2-8 =53.27 wt. %. DMM 8 is not detected in the final product.
[0048] The concentration distribution of final products in Embodiment 3 and Embodiment 4 is shown in the following table.
[0000]
Serial number
DMM 2
DMM 3
DMM 4
DMM 5-8
DMM n>8
Embodiment 3
25.02 wt. %
14.54
8.43
9.23
~0
wt. %
wt. %
wt. %
Embodiment 4
23.55 wt. %
13.71
7.50
8.51
~0
wt. %
wt. %
wt. %
[0049] As can be seen by analyzing the table, for the three-stage combination of slurry bed tank reactors connected in series using continuous operation, the operation scheme of successive stepwise cooling is compared with the isothermal reaction in which the temperature of the three reactors is equally kept at 100° C., and after the same reaction time of about 6 hours, it is found that the concentration of each kind of the target product of the former is higher than the latter, the overall yield of ΣDMM 2-8 is increased by about 4 percentage points, the proportion of DMM 5-8 in the target product is also higher. It is clearly indicated that for the multi-stage combination of slurry bed tank reactors connected in series using continuous operation, the reaction process of successive cooling provided by the present invention on the basis of thermodynamic equilibrium principle of the reaction system is also effective, it indeed promote the equilibrium of the reaction system to shift in the direction of producing the target product, it can not only increase the one-way overall yield of the target product, but also improve the selectivity of target products with higher degree of polymerization of methoxy groups, thus strengthen the synthesis reaction.
Embodiment 5
[0050] Experimental device of the process flow of this embodiment is shown in FIG. 1 . The feedstock solution is prepared according to a 1.5:1 molar ratio of trioxane metered in formaldehyde units to methylal, the solution is added into a 0.3 L single-stage stirred tank reactor, and then 001×7 strong acidic styrene type cation exchange resin catalyst at the amount of 3 wt % of the overall feedstock is added. The initial pressure of the reaction is controlled at about 2.0 MPa, and stirring speed is 250 r/min. And the isothermal reaction experiment using stepwise cooling is carried out in accordance with the following procedures: the reaction mixture is rapidly heated to 100° C., after that the isothermal reaction is carried out for 1 hour; the reaction temperature is rapidly cooled to 90° C., then the isothermal reaction is carried out for 1 hour again; the reaction temperature is rapidly cooled to 80° C. in a few minutes, then the isothermal reaction is carried out for 1 hour, and the reaction is completed after 3 hours in total of reaction. The sampling is started from when the reaction temperature reaches 100° C. and the timing is started, thereafter samples are taken once per hour for analysis of product composition.
[0051] The final overall yield of the target product is 47.55 wt. % after 3 hours.
Embodiment 6
[0052] The process flow of this embodiment is the same as Embodiment 1, as shown in FIG. 1 . The reaction feedstock and conditions are similar to Embodiment 5, and the difference is that the reaction temperature is controlled at 100° C. all the time, after 3 hours the reaction is completed. The final overall yield of the target product is 43.26 wt. %.
[0053] The concentration distribution of final products in Embodiment 5 and Embodiment 6 is shown in the following table.
[0000]
Serial number
DMM 2
DMM 3
DMM 4
DMM 5-8
DMM n>8
Embodiment 5
24.88 wt. %
12.25
5.50
4.92
~0
wt. %
wt. %
wt. %
Embodiment 6
24.30 wt. %
11.27
4.68
3.01
~0
wt. %
wt. %
wt. %
[0054] As can be seen by analyzing the table, the operation scheme of successive stepwise cooling is compared with the isothermal reaction in which the temperature is kept at the initial temperature of the aforementioned successive cooling, and after the same reaction time of 3 hours, it is found that the concentration of each kind of the target product of the former is higher than the latter, the overall yield of ΣDMM 2-9 is increased by about 4.3 percentage points, the proportion of DMM 5-8 in the target product is also higher. It is clearly indicated that successive cooling indeed promote the equilibrium of the reaction system to shift in the direction of producing the target product, it can not only increase the one-way overall yield of the target product, but also improve the selectivity of target products with higher degree of polymerization of methoxy groups, thus strengthen the synthesis reaction.
Embodiment 7
[0055] Experimental device of the process flow of this embodiment is shown In FIG. 2 . The feedstock solution is prepared according to a 1:1 molar ratio of trioxane metered in formaldehyde units to methylal, the solution is added into a three-stage combination of 5.0 L slurry bed tank reactors connected in series, the temperature of the first reactor, the second reactor and the third reactor is respectively controlled at 100° C., 85° C. and 70° C., with continuous feeding, and the average reaction time of each tank reactor is kept at about 1 hour. The type of catalyst and its amount used and other reaction conditions are the same to Embodiment 5. The operation is carried out continuously until the system is stable and samples are taken for composition analysis. The final overall yield of the target product is ΣDMM 2-8 =46-19 wt. %. DMM 8 is detected in the final product.
Embodiment 8
[0056] The process flow of this embodiment is shown in FIG. 2 . The feedstock solution is prepared according to a 1:1 molar ratio of trioxane metered in formaldehyde units to methylal, the solution is added into a three-stage combination of 5.0 L slurry bed tank reactors connected in series, the temperature of reactor of each stage is all controlled at 100° C., with continuous feeding, and the average reaction time of each tank reactor is kept at about 1 hour. The type of catalyst and its amount used and other reaction conditions are all the same to Embodiment 5. The operation is carried out continuously until the system is stable and samples are taken for composition analysis. The final overall yield of the target product is ΣDMM 2-8 =43.07 wt. %. DMM 8 is not detected in the final product.
[0057] The concentration distribution of final products in Embodiment 7 and Embodiment 8 is shown in the following table.
[0000]
Serial number
DMM 2
DMM 3
DMM 4
DMM 5-8
DMM n>8
Embodiment 7
24.45 wt. %
11.77
5.41
4.56
~0
wt. %
wt. %
wt. %
Embodiment 8
24.26 wt. %
11.21
4.60
3.00
~0
wt. %
wt. %
wt. %
[0058] As can be seen by analyzing the table, for the three-stage combination of slurry bed tank reactors connected in series using continuous operation, the operation scheme of successive stepwise cooling is compared with the isothermal reaction in which the temperature of the three reactors is equally kept at 100° C., and after the same reaction time of 3 hours, it is found that the concentration of each kind of the target product of the former is higher than the latter, the overall yield of ΣDMM 2-8 is increased by about 3.1 percentage points, the proportion of DMM 5-8 of the target product is also higher. It is clearly indicated that for the multi-stage combination of slurry bed tank reactors connected in series using continuous operation, the reaction process of successive cooling provided by the present invention on the basis of thermodynamic equilibrium principle of the reaction system is also effective, it indeed promote the equilibrium of the reaction system to shift in the direction of producing the target product, it can not only increase the one-way overall yield of the target product, but also improve the selectivity of target products with higher degree of polymerization of methoxy groups, thus strengthen the synthesis reaction.
[0059] The above data indicates that through the way of continuous stepwise cooling of the present invention using thermodynamic principle in order to break through the chemical equilibrium in the reaction and to promote continuously forward reaction is conductive to increase the content of the target product in the whole system, and meanwhile the distribution of products with higher degree of polymerization is better.
[0060] Obviously, the aforementioned embodiments are merely intended for clearly describing the examples, rather than limiting the implementation scope of the invention. For those skilled in the art, various changes and modifications in other different forms can be made on the basis of the aforementioned description. It is unnecessary and impossible to exhaustively list all the implementation ways herein. However, any obvious changes or modifications derived from the aforementioned description are intended to be embraced within the protection scope of the present invention. | The present invention relates to the field of chemical engineering and technology, in particular relates to the sub-field of synthesis of high quality alternative liquid engine fuel from non-petroleum based feedstock, more particularly relates to a method for regulating and optimizing the synthetic process of polyoxymethylene dimethyl ethers utilizing chemical thermodynamic principle. The process of the present invention Is achieved by conditions wherein the initial temperature of reaction is controlled at 100-120° C., then the temperature is reduced to 50-70° C. by successive stepwise cooling or programmed cooling,, the reaction pressure is controlled at 0.1-4.0 MPa, and the molar ratio of paraformaldehyde or trioxane metered in formaldehyde units to methylal in the feedstock is 1.5:1-8:1. In the process, higher overall yield of the target product can be achieved in the same reaction time, and selectivity of products with higher degree of polymerization of methoxy groups can be increased. | 2 |
FIELD OF THE INVENTION
[0001] The present invention relates generally to a tray device for a stroller, and more particularly to a tray device which is rotatable or detachable by press operation.
BACKGROUND OF THE INVENTION
[0002] A conventional tray accessory 8 for a stroller shown in FIG. 1 is disclosed in U.S. 2002/0175498 A1 laid-open patent application. One end of the tray accessory 8 is pivotally connected to a first handrail 82 of the stroller by a pin 81 and another end with a latch 83 is engaged into a recess 85 in a second handrail 84 of the stroller, whereby the conventional tray accessory 8 is connected to (the handrails of) the stroller.
[0003] In order to conveniently take the baby from and put the baby into the stroller, a tab 86 is pulled open to the extent that the latch 83 is slightly released from the recess 85 and then the end of the tray accessory 8 on the second handrail 84 is lifted so as to leave the tray accessory 8 hung on the first handrail 82 at another end and to form an opening between the first handrail 82 and the second handrail 84 .
[0004] However, the latch 83 of the conventional tray accessory 8 is inclined to be worn out after repeatedly engaging and disengaging, which results in infirm connection between the tray accessory 8 and the second handrail 84 . Therefore, due to the baby's playing with and shaking, the tray accessory 8 may accidentally escape from the second handrail 84 to make the baby riskily fall down from the stroller.
SUMMARY OF THE INVENTION
[0005] Accordingly, the present invention relates to a tray device for a stroller that can substantially obviate one or more of the problems due to the limitations and disadvantages of the related arts.
[0006] One object of the present invention is the provision of a rotatable and detachable tray device for a stroller wherein the connection between the tray device and the stroller is firm and safe.
[0007] Additional features and advantages of the invention will be set forth in the description which follows, and in portion will be apparent from the description, or may be learned by practice of the invention. The objectives and advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
[0008] To achieve these and other advantages and according to the purpose of the present invention, as embodied and broadly described, a tray device for being connected to a frame unit of a stroller comprises: a tray body having a first guider and a second guider; a slider having a first groove, the first guider being received in the first groove; an operating unit having a coupling piece and a second groove, the second guider being received in the second groove and the coupling piece substantially contacting with the slider; an elastic member having two opposed ends, one end contacting with the slider, another end contacting with the tray body; wherein when the operating unit is not actuated, the slider is situated at a first position and engaged with the frame unit so as to connect the tray device and the frame unit together; when the operating unit is actuated, the slider is moved to a second position and escaped from the frame unit so as to separate the tray device and the frame unit.
[0009] It is preferred that the frame unit has a neck portion for connecting with one end of the tray body.
[0010] It is preferred that the tray device has the slider, the operating unit and the elastic member respectively at each of two ends thereof; when the operating unit situated at either end of the tray device is actuated, the tray device can be rotated relative to the frame unit; when the operating units situated at both ends of the tray device are actuated, the tray device can be detached from the frame unit.
[0011] It is preferred that the slider has a stake and the frame unit has a hole, and thus the tray device and the frame unit can be connected together by the stake being received in the hole.
[0012] It is preferred that the first groove is situated at one end of the slider and the slider further has a third groove at another end thereof for receive a third guider of the tray device.
[0013] It is preferred that the another end of the elastic member contacts with the third guider.
[0014] It is preferred that the coupling piece of the operating unit is a tongue which contacts with a rib of the slider.
[0015] It is preferred that the tray device further has a cover for at least shield partially the slider and the operating unit.
[0016] It is preferred that the tray body has an aperture and the operating unit has a head portion which is received in the aperture and at least partially protrudes out of the tray body.
[0017] It is to be understood that both the forgoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a portion of the specification, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention. In the drawings:
[0019] FIG. 1 is a front plane view of a conventional tray accessory illustrating a post-rotated state;
[0020] FIG. 2 is a perspective view of the tray device mounted to a stroller according to the present invention;
[0021] FIG. 3 is a sectional perspective view around the joint of the tray device and an armrest of the stroller according to the present invention;
[0022] FIG. 4 is a bottom perspective view according to the present invention showing a state of the tray device engaged to the armrest without a cover;
[0023] FIG. 5 is a bottom perspective view according to the present invention showing a state of the tray device detachable from the armrest without a cover;
[0024] FIG. 6 is a bottom perspective view according to the present invention showing that the tray device is engaged with two armrests; and
[0025] FIG. 7 is a perspective view according to the present invention showing that the tray device is engaged with only one armrest but is separated with another armrest.
DETAILED DESCRIPTION OF THE INVENTION
[0026] The present invention is adapted to be utilized not only in a stroller, but also in the apparatuses for babies' and children's riding, sitting and lying, such as a high chair or a swinging chair etc.
[0027] As shown in FIG. 2 , a stroller 1 according to the present invention comprises a frame unit 2 and a tray device 3 . The frame unit 2 further includes a front lower bar group 21 , a rear lower bar group 22 , a rear upper bar group 23 and two, left and right, armrests 24 , all of which are pivotally connected together. As shown in FIG. 7 , each armrest 24 , at front end thereof, has a neck portion 241 with a smaller diameter, a ring portion 242 with a larger diameter, and a hole 243 formed at the centers of the neck portion 241 and the ring portion 242 . The tray devices 3 of various type of the stroller 1 may be respectively mounted at the front lower bar group 21 , the rear lower bar group 22 , the rear upper bar group 23 or the armrests 24 . The preferred embodiment hereinafter is illustrated about the case that the tray devices 3 is mounted at the armrests 24 .
[0028] As shown in FIGS. 3 to 5 , the tray device 3 includes a substantially banana-shaped tray body 31 , a substantially U-shaped slider 32 , an operating unit 33 , an elastic member 34 , and a cover 35 .
[0029] The tray body 31 has a base 311 and a skirt 312 perpendicularly extending downwardly around the base 311 . At each of two opposed ends of the tray body 31 , the skirt 312 respectively has an U-shaped opening 314 and an aperture 315 substantially oriented forwardly. A first guider 316 , a second guider 317 , and a third guider 318 downwardly protrude, near each opening 314 , from the base 311 .
[0030] The slider 32 includes a stake 321 longitudinally extending outwardly from the U-shaped closed end thereof, an arc of flange 322 upwardly extending from the U-shaped closed end thereof, an U-shaped rib 323 downwardly extending from the open end thereof, a first groove 324 defined by the flange 322 , and a third groove 325 defined by the rib 323 .
[0031] The operating unit 33 includes a cylinder head portion 331 and a plate-shaped tail portion 332 . The head portion 331 and the tail portion 332 may be integrally formed together, or be separately formed and then be assembled together. The tail portion 332 has a coupling piece 333 , such as an inclined tongue, at the middle section thereof and a second groove 334 at the free end thereof.
[0000] Assembling of the Tray Device 3
[0032] First, the slider 32 is placed at the bottom surface of the base 311 of the tray body 31 and simultaneously the first guider 316 is accommodated in the first groove 324 as well as the third guider 318 is accommodated in the third groove 325 . Next, the elastic member 34 is put into the hollow slider 32 . One end of the elastic member 34 is abutted against the closed end of the slider 32 and another end of the elastic member 34 is abutted against the third guider 318 . Then, the operating unit 33 is provided under the slider 32 and at the same time the head portion 331 is received in the aperture 315 as well as the second guider 317 is accommodated in the second groove 334 . In this state, the coupling piece 333 substantially contacts with the rib 323 and the tail portion 332 can block the elastic member 34 from dropping out of the slider 32 . Finally, the cover 35 is secured to the tray body 1 by screws (not shown) so as to shield the slider 32 and the operating unit 33 except the front part of the head portion 331 , which is revealed outside of the skirt 312 of the tray body 31 . As far as the positions for the screws, the centers of the second guider 317 and the third guider 318 may be included.
[0000] Operating of the Tray Device 3
[0033] As shown in FIGS. 4 and 5 , when the head portion 331 of the operating unit 33 is pressed, the operating unit 33 slides along the direction of the arrow A under the guidance of the second guider 317 . Simultaneously, the rib 323 is pushed by the coupling piece 333 to actuate the slider 32 sliding along the direction of the arrow B under the guidance of the first guider 316 and the third guider 318 , which results in the elastic member 34 is compressed. In this state, because the stake 321 has been moved along the direction of the arrow B, the tray body 31 can be installed to the armrest 24 by put the neck portion 241 of the armrest 24 into the U-shaped opening 314 . Then, after the hand pressing the operating unit 33 is withdrawn, the slider 32 is moved by the restoration force of the elastic member 34 along the opposed direction of the arrow B to the extent that the stake 321 is inserted into the hole 243 of the armrest 24 . In this situation, the tray device 3 is unable to escaped from the armrest 24 along the axial or radial direction of the stake 321 so that the tray device 3 can be firmly connected with the armrest 24 . Also, the operating unit 33 is cooperated by the rib 323 and slides back along the opposed direction of the arrow A, as shown in FIG. 4 .
[0034] As shown in FIG. 5 , when it is desired to take the baby from or put it into the stroller 1 , the head portion 331 of the operating unit 33 is pressed again to the extent that the stake 321 escapes from the hole 243 of the armrest 24 . Then the tray device 3 is upwardly lifted to completely separate the end of the tray device 3 from the armrest 24 . If this operation is executed at both ends of the tray device 3 , the tray device 3 can be entirely detached from the armrest 24 . Alternatively, if this operation is executed at only one end of the tray device 3 , another end of the tray device 3 can by no means escape from the armrest 24 along the axial direction of the stake because the skirt 312 at this another end is blocked by the ring portion 242 . Therefore, the tray device 3 can invert about 180 degrees as shown in FIG. 7 relative to the neck portion 241 , which functions as a pivot, of the armrest 24 at this another end. Consequently, there is no member between two, left and right, armrests 24 , which is convenient for taking baby from and put baby into the stroller 1 .
[0000] Advantages
[0035] By pushing the stake 321 into the hole 243 of the armrest 24 , the tray device 3 disclosed in the present invention can be firmly connected to the armrests 24 . When the stake 321 escapes from the hole 243 , there happens no wear. Therefore, even the operation of mounting and dismounting is repeated but there is no risk of wearing out the related elements. Since no wear may deteriorate the firm connection between the tray device 3 and the armrest 24 , then the baby is secure against dropping from the stroller 1 . Accordingly, the tray device 3 of the present invention is of great safety.
Other Embodiments
[0036] The first guider 316 and the third guider 318 above-mentioned can be combined to a new guider with proper length only if the new guider can maintain smooth movement and direction of the slider 32 . Similarly, the first groove 324 and the third groove 325 above-mentioned can be combined to a new groove to match with the new guider.
[0037] This invention has been disclosed in terms of specific embodiments. It will be apparent that many modifications can be made to the disclosed structures without departing from the invention. Therefore, it is the intent of the appended claims to cover all such variations and modifications as come within the breadth and scope of this invention. | A tray device for a stroller comprises a tray body as well as, at each end of both ends of the tray body, a slider movable relative to the tray body, an operating unit for pushing away the slider, and an elastic member for pushing back the slider. When the operating units both are executed, the stakes of the sliders are respectively escaped from two armrests to enable the tray device being detached from the armrests. If only one operating unit is actuated, the tray device can be turned over. | 1 |
TECHNICAL FIELD
[0001] This disclosure relates to a method of manufacturing sheet metal blanks that include an opening subsequently formed in a drawing operation or other type of forming operation.
BACKGROUND
[0002] Manufacturing sheet metal parts generally begins with a blanking operation where blanks are cut from coils of rolled steel or aluminum. The outer perimeter and large openings may be trimmed to form a blank that is then formed in subsequent drawing, flanging, punching, piercing and hemming processes. One example of a part that is blanked with a large opening is a body side panel that spans the side of a vehicle and defines the opening that receives the doors in a nesting relationship. One problem with forming precut openings in a blank is that in subsequent forming operations the material around the opening must flow from both the inside of the opening and the areas outside the opening. The precut opening is expanded when the blank is formed and may form splits in the material around the opening.
[0003] With the need to reduce the weight of vehicles to meet fuel economy standards, the development of sheet metal parts made from aluminum or high strength alloys is increasing. Aluminum and high strength steel are less malleable than mild steel and the problems relating to splitting at the inner perimeter of larger openings is more prevalent. Small cracks or small imperfections in the cut edge formed when aluminum blanks are cut out expand to form splits in a subsequent forming operations because additional metal is drawn from the inside of the opening.
[0004] The root causes of splitting at the inner edge of the blank during draw die expansion in subsequent forming operation originates from excessive strain hardening and small imperfections due to rough fracture surfaces, micro-cracks, burrs, and gall marks. Excessive strain hardening and imperfections severely limit the expansion capacity of the metal. Avoiding problems relating to splits caused by imperfections in precut openings in aluminum panels limits opportunities to use aluminum sheet metal parts. Panel splits may cause substantial yield losses in the stamping process due to the need to scrap parts that have splits in critical areas. In addition, problems relating to splits in panels result in cost overruns, supply shortages, potential quality problems, and reduced manufacturing line availability.
[0005] This disclosure is directed to solving the above problems and other problems as summarized below.
SUMMARY
[0006] According to one aspect of this disclosure, a method is disclosed for manufacturing a sheet metal part. The method includes the steps of cutting a plurality of blanks defining internal openings from a plurality of sheet metal segments. Stacking the plurality of blanks with the internal openings aligned and machining inner perimeters of the internal openings with a rotary cutting tool to a finish dimension.
[0007] According to other aspects of the method, the method may further comprise clamping the plurality of blanks together before machining. The blanks may be clamped together in a numerically controlled machine tool. The method may further comprise forming the blanks individually in a sheet metal forming operation, wherein the inner perimeter of the internal openings in the blank are expanded as the blank is formed. The rotary cutting tool may be a milling tool. The sheet metal part may be a body side panel for a vehicle that defines a door or window opening or may be another type of panel having an opening or a critical edge area that is expanded in subsequent forming operations.
[0008] According to another aspect of this disclosure, a system is disclosed for manufacturing a sheet metal part from a blank defining an opening. The system comprises stacking a stack of blanks on a base with the openings generally in alignment. A machine tool including a rotary cutter removes material from the openings in the stack of blanks to form a machined blank edge. A forming tool subsequently forms and expands the machined blank edges in each of the machined blanks.
[0009] The system may further comprise a clamping apparatus clamping the stack of blanks on the base while the machine tool cuts material from the openings. The base may include a spacer disposed below the stack of blanks providing clearance for the machine tool to cut material from all of the blanks stacked on the base.
[0010] According to another aspect of the disclosure an article of manufacture is disclosed that comprises a blank defining an internal opening that is initially punched from a sheet metal segment. An inner periphery of the internal opening is formed as a machined surface. The machined surface may be a milled surface. The article of manufacture may be a body side panel for a vehicle and the internal opening may be a door opening, a window opening, or a relief opening.
[0011] According to another aspect of this disclosure, a method is disclosed for manufacturing a sheet metal part by machining inside or outside edges of a blank. The method begins with the step of cutting a plurality of blanks each including a blanked edge from a plurality of sheet metal segments. The blanks are then stacked with the blanked edges generally aligned. The blanked edges of the plurality of blanks are then machined with a machining tool to a finish dimension.
[0012] The above aspects of this disclosure and other aspects will be described below with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 a is an exploded perspective diagrammatic view of a blanking press for cutting openings in a blank and stacking a stack of blanks on a pallet or other supporting surface according to one aspect of this disclosure.
[0014] FIG. 1 b is a perspective view of one example of a body side panel blank.
[0015] FIG. 2 is a perspective view of a numerically controlled machine milling the inner periphery of an internal opening in a plurality of blanks that are clamped in place with the openings in alignment.
[0016] FIG. 3 is a fragmentary cross-section view taken along the line 3 - 3 in FIG. 2 showing a rotary cutting tool removing material from the inner periphery of the internal openings in the stack of blanks.
[0017] FIG. 4 is a diagrammatic perspective view of a draw die for a body side panel with a blank loaded into the die to be drawn into a desired shape.
[0018] FIG. 5 is a flowchart illustrating the steps of the manufacturing process for forming a sheet metal panel including a large internal opening that is machined to remove edge defects.
DETAILED DESCRIPTION
[0019] The illustrated embodiments are disclosed with reference to the drawings. However, it is to be understood that the disclosed embodiments are intended to be merely examples that may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed are not to be interpreted as limiting, but as a representative basis for teaching one skilled in the art how to practice the disclosed concepts.
[0020] Referring to FIGS. 1 a and 1 b, a blanking press 10 is illustrated that includes an upper blanking die 11 and a lower blanking die 12 that cut large openings, such as a door opening 13 , window opening 14 , or relief opening in a blank 15 . The door opening 13 , window opening 14 , or relief opening are referred to as internal openings. The blank 15 is placed on a stack 16 of other blanks on a pallet 17 generally in alignment with a stack 16 of other blanks 15 when the internal openings are cut out of the blank 15 . The pallet 17 may be of the type used on a stamping press (shown in FIG. 4 ) or may be a dedicated machining pallet. A space 18 is defined by the supporting member, or pallet 17 , below the internal openings to facilitate machining the internal openings in the stack of blanks 16 .
[0021] Referring to FIGS. 1 a, 1 b, and 2 , inner peripheries 20 of internal openings 19 contain a band of highly work hardened material which may include edge defects (not shown) created when the internal openings 19 are blanked. The blanks 15 may be imperfectly stacked with some of the blanks 15 being offset relative to the other blanks 15 in the stack 16 . The blanks 15 are “generally aligned” on the stack meaning that the blanks 15 are stacked within +/−1 mm of the average stack location with the overall stack being +/−1 mm over the height of the stack 16 .
[0022] Referring to FIG. 2 , a plurality of blanks 15 , or stack of blanks 16 , is shown supported on a pallet 17 and sandwiched between a top plate 21 and the pallet 17 . The internal openings 19 in the stack of blanks 16 are held in place by a plurality of clamping members 22 that are shown engaging the top plate 21 . The top plate 21 functions to distribute the clamping loads applied by the clamping members 22 . Other clamping arrangements may also be used to apply a clamping load to the stack 16 . A numerically controlled machine 24 (herein after a “NC machine”) is shown with a rotary cutting tool 28 , or mill, that machines the inner periphery 20 of the internal openings 19 .
[0023] Referring to FIGS. 2 and 3 , the stack of blanks 16 is shown being compressed between the top plate 21 and pallet 17 . The rotary cutting tool 28 is shown performing a NC machine controlled milling operation on the inner periphery 20 of the internal openings 19 . The cutter 28 removes material from the inner periphery 20 of the stack of blanks 16 that may be milled as if it was a monolithic metal structure because of the pressure applied by the clamping members 22 to the top plate 21 . The NC machine 24 is initialized by aligning the NC machine 24 relative to the location of the stack 16 on the pallet 17 . The rotary cutting tool 28 includes a plurality of cutter inserts 30 that form a milled surface 32 on the abutting blanks 15 to a finish dimension. The machining operation may be performed with or without a machining lubricant.
[0024] At least one metal thickness of the sheared edge, or blanked edge, is removed to facilitate subsequent hole expansion. The internal openings 19 may be milled up to 4 mm to compensate for stacking tolerance.
[0025] As shown in FIG. 3 , several machined blanks 34 are illustrated in the top portion of the stack of blanks 16 . The rotary cutting tool 28 , as illustrated, moves from the top of the stack of blanks 16 (as shown in solid lines) to the position shown in phantom lines at the bottom of the stack of blanks 16 . A spacer 36 is placed on the base 17 , or pallet, to allow the rotary cutting tool 28 to mill all of the blanks 15 in the stack of blanks 12 by providing a clearance area 38 defined below the stack of blanks 16 and above the pallet 17 . The spacer 36 and pallet 17 are shown as separate parts in FIG. 3 . Alternatively, the space 18 may be defined by the pallet as shown in FIG. 1 a.
[0026] Referring to FIG. 4 , a blank 15 for a body side panel (not shown) is disposed in a draw die 42 that is part of a press line that forms the body side panel. The sheet metal press 42 expands the internal openings 19 in individual blanks 15 .
[0027] Referring to FIG. 5 and with continued reference to the other drawings, the process is disclosed with reference to a flowchart 50 . The process begins by producing a blank 15 in a blanking press 10 , or punching operation, to form the outer periphery of the blank and internal openings 19 . At 52 , the blanks 15 are generally aligned and stacked into a stack of blanks 16 , however, some of the blanks 15 may be imperfectly stacked. Imperfectly stacked blanks 15 with misaligned internal openings 19 may be compensated for by subsequent machining to the finish dimension. At 54 , the stack of blanks 16 is clamped in a NC machine 24 that holds the blanks 15 together and generally in alignment. At 56 , the inner periphery 20 of the internal opening 19 is machined to the finish dimension of the milled surface 32 . After machining, the stack of blanks 16 is cleaned by brushing or blowing machining chips off of the stack 16 . At 58 , the blank 15 is separated from the stack of blanks 16 and each individual blank 15 is formed in a sheet metal press 42 to the desired overall shape of the finished part (not shown).
[0028] While the method is described with reference to milling internal openings 19 such as door openings 13 and window openings 14 , the method is also applicable to smaller openings or outside trim edges that are subsequently stretched in the forming process.
[0029] The embodiments described above are specific examples that do not describe all possible forms of the disclosure. The features of the illustrated embodiments may be combined to form further embodiments of the disclosed concepts. The words used in the specification are words of description rather than limitation. The scope of the following claims is broader than the specifically disclosed embodiments and also includes modifications of the illustrated embodiments. | A method and a system are disclosed for making an article of manufacture from a blank defining an internal opening. A stack of blanks are aligned and the internal openings of the blanks in the stack of blanks are machined by a rotary cutting tool to a finished dimension. The blanks are clamped together before machining in a numerically controlled machine tool. The blanks are subsequently formed individually in a sheet metal forming operation in which the inner perimeter of the internal openings is expanded as the blank is formed. | 1 |
[0001] This is a Continuation of application Ser. No. 14/477,835 filed Sep. 4, 2014, which claims the benefit of U.S. Provisional Application No. 61/959,848 filed Sep. 4, 2013. The disclosure of the prior application is hereby incorporated by reference herein in its entirety.
FIELD OF INVENTION
[0002] The present invention relates to step ladders and more particularly pertains to an improvement to an A-frame ladder allowing it to be placed on uneven surfaces.
BACKGROUND
[0003] Stepladders are free-standing ladders that can be erected without support from a wall, and can be folded together under transport. A stepladder consists of a step frame, which is pivotally attached to a smaller support frame. The step frame includes a number of rungs, or steps. Steps are climbing supports with “walking and/or stepping surfaces” typically ranging anywhere from 8 cm deep to 2-5 cm. The upper step is often a step-plate or platform, enabling a user to stand and move safely and comfortable. The step and support frames are connected by some locking mechanism that prevents the stepladder from collapsing.
SUMMARY OF THE INVENTION
[0004] The present invention overcomes a limitation of the prior designs, specifically by providing an easy to use mechanism wherein the stepladder is self-leveling. Whilst similar to conventional stepladders in some respects, the instant invention is able to accommodate uneven ground by virtue of a unique hinge apparatus.
[0005] A conventional fold out type stepladder only works well on a flat surface and is very unstable on anything else. In such instances, all of the legs of the ladder fail to touch the surface. In such instances, the conventional stepladder is not stable and not easy to stand upon, when set on uneven ground. For example, a fruit picker's ladder solves part of the problem by only having three legs; two in a step frame and a single leg at the back. They work well when pushed between the branches and foliage of a tree, but are mostly unstable when free standing.
[0006] Many inventions have tried to address this problem but they are inadequate at best; most being of the extendable leg type. They are awkward and time consuming to set up, particularly when the ladder has to be moved to many locations as in fruit picking. In accordance with aspects of the present disclosure, the instant self-leveling stepladder with a universal hinge joint provides many new advantages that traditional a-frame step ladders are not capable to deliver.
[0007] In the description herein, some details are provided, such as examples of components and/or methods, to provide a thorough understanding of embodiments of the present invention. One skilled in the relevant art will recognize, however, that an embodiment of the invention can be practiced without one or more of the specific details, or with other apparatus, systems, assemblies, methods, components, materials, parts, and/or the like. In other instances, well-known structures, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Embodiments of the present disclosure are described herein with reference to the drawings, in which:
[0009] FIG. 1 is a side front perspective drawing image of the self-leveling step ladder self-leveling on uneven ground, in accordance with an embodiment of the instant invention;
[0010] FIG. 2 is a side rear perspective drawing image of the self-leveling step ladder self-leveling on uneven ground, in accordance with an embodiment of the instant invention;
[0011] FIG. 3 is a front perspective drawing image of the self-leveling step ladder self-leveling on uneven ground, in accordance with an embodiment of the instant invention;
[0012] FIG. 4 is an exploded top perspective image of the hinge comprised of a rubber tendon joint as the universal hinge, in accordance with one embodiment of the instant invention;
[0013] FIG. 5 is an exploded top perspective image of the hinge comprised of a ball and socket joint as the universal hinge, in accordance with another embodiment of the instant invention;
[0014] FIG. 6 is an exploded top perspective image of the hinge comprised of a mechanical joint as the universal hinge, in accordance with another embodiment of the instant invention;
[0015] FIG. 7 is an exploded top perspective image of the hinge comprised of a set of interlocking eye joints serving as the universal hinge, in accordance with another embodiment of the instant invention; and
[0016] FIGS. 8A and 8B are side and top views of the hinge comprised of a rope threaded ball joint as the universal hinge, in accordance with another embodiment of the instant invention.
[0017] FIG. 9 is an alternate embodiment illustrating a Y-shaped frame side, in accordance with another embodiment of the invention.
[0018] The novel features which are characteristic of the invention, as to organization and method of use, together with further objects and advantages thereof, may be better understood from the following brief disclosure considered in connection with the accompanying drawings in which one or more preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention.
DETAILED DESCRIPTION
[0019] The novelty of this invention revolves around the movement allowed by an unconventional hinge. Its unique design can be applied to almost any type of fold out step ladder. By virtue of the hinge, the two sides of a fold-out step ladder are allowed full movement in all planes. The two sides can open conventionally and also swing from side to side and at angles to each other. Their movement allows all four legs of the ladder to find contact with uneven ground and provide a stable platform to climb up on.
[0020] The universal hinge may be many possible versions, as illustrated in FIGS. 4-8 . For example, the universal joint may comprise an embodiments as simple as two linked eyes ( FIG. 7 ), one on each step frame, a piece of rope or cable passing through each frame. Or, alternatively, in another embodiment, a more complex version such as a knuckle style joint ( FIG. 5 ), similar to that used in automobile suspension. Whatever way, free movement to both frames will allow for all four legs to be stable on uneven ground.
[0021] Although this is a novel universal joint, there is nothing highly technological about the hinge. It could be merely two eye bolts linked together or two U-bolts; one attached to either frame. It could be as simple as a cable or tendon ( FIG. 6 ) from one side to the other. This design allows the ladder to open conventionally and also allows the frames to move from side to side independent of each other. It is this free movement in all planes that allows for all four legs to contact the uneven ground at the same time. The ladder very easily and quickly finds a stable position for safe climbing.
[0022] The applications and usage are many for the instant invention, ranging from a two or three step utility ladder, to high reaching ladders suitable for fruit picking. The invention will suit any application using a four-legged adjustable ladder on uneven ground. This style of four legged fruit picker ladder is much more stable than the three legged version. All versions allow movement in three planes to allow four-leg contact and engagement with uneven ground. It is to be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Thus, while the present invention has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosures, and it will be appreciated that in some instances some features of embodiments of the invention will be employed without a corresponding use of other features without departing from the scope and spirit of the invention as set forth.
[0023] For example, the ladder having a wider base going up to a more triangular pointpicker style—could be made of aluminum and fiberglass sides and round ladder rungs. Various sizes will accommodate all sorts of picking from straddling berries to picking coffee, for example, on mountain sides and all kinds or other fruits up to 16 feet or more. In other examples, configuring the instant invention as a low level two or three step ladder—non wobbly—for garden use, clipping and pruning.
[0024] Therefore, many modifications may be made to adapt a particular situation or material to the essential scope and spirit of the present invention. It is intended that the invention not be limited to the particular terms used and/or to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include any and all embodiments and equivalents falling within the scope of the instant disclosure.
[0025] The foregoing description of illustrated embodiments of the present invention, including what is described herein, is not intended to be exhaustive or to limit the invention to the precise forms disclosed herein. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the present invention, as those skilled in the relevant art will recognize and appreciate. As indicated, these modifications may be made to the present invention in light of the foregoing description of illustrated embodiments of the present invention and are to be included within the spirit and scope of the present invention. | A self leveling stepladder with a universal hinge joint providing many new advantages that traditional a-frame step ladders are not capable to offer. | 4 |
This is a continuation of U.S. Pat. application Ser. No. 481,058, filed Feb. 16, 1990 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of weighing and taking out a powdered dye used for dye adjusting purposes in case of dyeing textile products and synthetic resin products, etc. and an apparatus suitable for carrying out the method, and more particularly, to a method and an apparatus for weighing and taking out a powdered dye efficiently to thereby enable the error or deviation from a required quantity of a powdered dye to be minimized.
2. Description of the Prior Art
To conduct dyeing treatments satisfactorily, it is required basically to adjust a dye liquor containing a proper required quantity of a dye. In case the dye is powdery, it is not always easy to weigh and take out a required quantity of the powdered dye accurately.
As a conventional method of weighing and taking out a powdered dye stored in a container, there has so far been carried out to take out the dye in an approximately required quantity by means of a measuring means such as a measuring cup, or by flowing it out from the lower part of the container and compensating for the surplus or the deficiency of the dye by means of an weighing instrument such as an electronic weigher, or alternatively to dilute the powdered dye, taken out by the same procedure as mentioned above in a quantity slightly more than the required amount, with a liquid such as, for example, water so as to prepare a dye liquor having a known dye concentration, and then taking the dye liquor in a quantity which contains the proper required quantity of the powdered dye out of the prepared dye liquor.
Out of the above-mentioned two conventional methods of weighing and taking out powdered dye, the former method wherein a dye is taken out in powdery state has been conducted commonly in laboratories. However, since this method is troublesome in weighing and compensating the surplus or the deficiency and is therefore inefficient for industrial application, it has been carried out generally to control the quantity of a powdered dye flowing out from a container by means of a fixed quantity delivery means in an error range of ±0.5-0.25 gr.. In case of dyeing, if the quantity of a powdered dye contained in a dye liquor has an error or deviation of 1% or more from a required quantity, then there occurs a visually different result of dyeing. Therefore, the above-mentioned former method of taking out a powdered dye has been used in case of large lot dyeing using a dye liquor containing a required quantity of more than 50 gr. of the dye in which the dye can be weighed and taken out at a high accuracy, but in case of small lot dyeing using a dye liquor containing a required quantity of less than 50 gr. of the dye has required troublesome reweighing and compensation.
Whilst, the latter method wherein a powdered dye is weighed and taken out in the form of a diluted solution which contains a required quantity of the dye provides a highly accurate weighing depending on the degree of dilution. According to this method, however, the quantity of the diluted solution increases with an increase in the required quantity of the dye thus posing problems on installation and operations, and also in case a large quantity of the dye liquor is kept in custody, there is a possibility of aging of the dye liquor. Therefore, the latter method is used only for trial dyeing, sample dyeing and small-lot dyeing, etc. wherein a small quantity of a dye is taken out and used.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-mentioned circumstances in the prior art, and has for its object to provide a method of weighing and taking out a powdered dye, which is completely free from bad influence by an error which occurs at the time of weighing and taking out the powdered dye and which enables the dye to be weighed and taken out quickly and at a high accuracy regardless of the required quantity of the dye thereby improving the efficiency of dyeing operation and achieving a satisfactory result of dyeing, and also an apparatus suitable for carrying out the method.
To achieve the above-mentioned object, according to a first aspect of the present invention, there is provided a method of weighing and taking out a powdered dye, comprising, upon weighing and taking out a required quantity of the powdered dye used for dye adjusting purposes, a first step of taking out and weighing the powdered dye in a quantity slightly less than the required quantity; a second step of taking out and weighing the powdered dye in a quantity slightly more than the value of difference between the weighed value of the powdered dye obtained in the first step and the required quantity, and adding to the powdered dye a liquid, such as water or a solvent or a dispersion medium, at a particular ratio to the weighed value to prepare a diluted solution having a known dye concentration, and a third step of partially taking the diluted solution in a predetermined quantity which contains the powdered dye of the value of difference out of the diluted solution prepared in the second step and adding it to the powdered dye obtained in the first step.
To achieve the above-mentioned object, according to a second aspect of the present invention, there is provided a method of weighing and taking out a powdered dye, comprising, upon weighing and taking out a required quantity of the powdered dye used for dye adjusting purposes; a first operation of weighing and taking out the powdered dye by setting a quantity obtained by subtracting a known maximum powdered dye taking-out error based on powdered dye taking-out means from the required quantity as a target value; a second operation of taking out and weighing the powdered dye in a quantity more than the maximum powdered dye taking-out error, and adding to the powdered dye a liquid, such as water or a solvent or a dispersion medium at a particular ratio to the weighed value to prepare a diluted solution having a known dye concentration; and a third operation of taking partially the diluted solution in a predetermined quantity, which includes the value of difference between the weighed value of the powdered dye obtained in the first operation and the required quantity, out of the diluted solution prepared in the second operation, and adding the diluted solution to the powdered dye obtained in the first operation.
To achieve the above-mentioned object, according to a third aspect of the present invention, there is provided an apparatus for weighing and taking out a powdered dye, comprising: a powdered dye storage tank (1), a large quantity powdered dye discharge pipe (2) and a small quantity powdered dye discharge pipe, each being connected to the lower part of the storage tank and each having a fixed quantity delivery means associated therewith; a first dye container located below the large quantity powdered dye discharge pipe and placed on a first weighing device; a second dye container located below the small quantity powdered dye discharge pipe and placed on a second weighing device; a liquid supply pipe for supplying a liquid such as water or a solvent or a dispersion medium into the second dye container; and a pump piping system for transferring a predetermined quantity of a diluted solution having a particular dye concentration prepared in the second dye container into the first dye container, wherein the operations of the fixed quantity delivery means associated with the large quantity powdered dye discharge pipe and the small quantity powdered dye discharge pipe, respectively, the liquid supply pipe and a pump of the pump piping system are controlled by a computor in accordance with the weighed value or values obtained as a result of weighing by any one or both of the weighing devices.
To achieve the above-mentioned objects, in accordance with a fourth aspect of the present invention, there is provided an apparatus for weighing and taking out plural kinds of powdered dyes, comprising: a plurality of powdered dye storage tanks located in a row; large quantity powdered dye discharge pipes each having a fixed quantity delivery means associated therewith and being connected to the lower part of each storage tank so as to project on one side of the row of the storage tanks; small quantity powdered dye discharge pipes each having a fixed quantity delivery means associated therewith and projecting on the other side of the row of the tanks; a first weighing device mounted so as to be movable on a path located below the large quantity powdered dye discharge pipes of the storage tanks and extending in parallel with the row of the tanks; a first dye container resting on the first weighing device; a second weighing device mounted so as to be movable on a path located below the small quantity powdered dye discharge pipes of the storage tanks and extending in parallel with the row of the tanks; second dye containers each being located below the small quantity powdered dye discharge pipe of each storage tank and between the small quantity powdered dye discharge pipe and the path on which the second weighing device is moved, each of the second dye containers being located on and supported by the second weighing device so as to be selectively weighed by the latter every storage tank; liquid supply pipes each supplying a liquid such as water or a solvent or a dispersion medium into each of the second dye containers associated therewith; and pump piping systems provided separately for each of the second dye containers so as to transfer a diluted solution having a particular dye concentration prepared therein into the first dye container, wherein the movement of the first and second weighing devices to positions opposite to a particular one of the powdered storage tanks located in a row, and operations of the fixed quantity delivery means associated with the large quantity powdered dye discharge pipe and the small quantity powdered dye discharge pipe, respectively, of the particular storage tank, the two weighing devices, the liquid supply pipe and a pump of the pump piping system associated with the particular storage tank are controlled by a computor in accordance with a particular program and the values obtained as a result of weighing by the two weighing devices.
According to the method of the present invention as set forth in the first and second aspects, a powdered dye can be weighed and taken out easily and with a high accuracy by taking out and weighing most of a required quantity of the powdered dye directly in a powdery state, and taking out the remaining quantity of the powdered dye separately in the state of a diluted solution thereby eliminating the bad influence due to an error range in the discharge by the fixed quantity delivery means. Further, according to the first apparatus set forth in the third aspect of the present invention, the above-mentioned method for weighing and taking out a single powdered dye can be carried out simply. Still further, according to the second apparatus as set forth in the fourth aspect, the above-mentioned method can be effected repeatedly to weigh and takeout plural kinds of powdered dyes in turn and continuously in accordance with their respective required quantity. The use of the second apparatus is extremely advantageous in terms of costs of equipment and operation as compared with the case of using a plurality of the first apparatuses.
The above-mentioned and other objects, aspects and advantages of the present invention will become apparent to those skilled in the art by making reference to the following description and the accompanying drawings in which preferred embodiments incorporating the principles of the present invention are shown by way of example only.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary front view showing the section of the principal parts of a first apparatus according to the present invention;
FIG. 2 is a horizontal sectional view of a powdered dye storage tank;
FIGS. 3 and 4 are sectional views of the tank taken along lines III--III and IV--IV, respectively, in FIG. 2;
FIG. 5 is a fragmentary front view showing the section of the principal parts of a second apparatus according to the present invention; and
FIG. 6 is a plane view of the second apparatus of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The method and apparatus of the present invention will now be described below by way of embodiments thereof with reference to the accompanying drawings.
FIG. 1 is a fragmentary front view showing the section of the principal parts of the first apparatus according to the present invention.
In the drawings, reference numeral 1 denotes a storage tank for storing a powdered dye; 2 a large quantity powdered dye discharge pipe projecting from the lower part of the storage tank 1 and provided with a fixed quantity delivery means; 3 a small quantity powdered dye discharge pipe provided with a fixed quantity delivery means; 21 a first weighing device which is an electronic weigher located below the large quantity powdered dye discharge pipe 2; 19 a first dye container placed on the first weighing device 21; 22 a second weighing device which is an electronic weigher located below the small quantity powdered dye discharge pipe 3; and 20 a second dye container placed on the second weighing device 22.
Further, reference numeral 25 denotes a liquid supply pipe for supplying a liquid such as water or a solvent or a dispersion medium for dye into the second dye container 20; 26 a stirrer; and 30 a pump piping system which includes a pump 31, a suction pipe 32 connected to the suction side of the pump 31 and which is inserted into the second dye container 20, and a discharge pipe 33 whose leading end opens above the first dye container 19.
Reference numeral 40 denotes a bed; 41 a cover; 42 and 43 branckets for supporting rotating drive shafts 4, 5 adapted to actuate the fixed quantity delivery means associated with the above-mentioned large quantity powdered dye discharge pipe 2 and small quantity powdered dye discharge pipe 3, respectively; and 44 electrical wirings for the first and second weighing devices 21 and 22.
FIGS. 2, 3 and 4 show the large quantity powdered dye discharge pipe 2 and the small quantity powdered dye discharge pipe 3, respectively, connected to the lower part of the storage tank 1, and the fixed quantity delivery means associated with the discharge pipes 2 and 3, respectively. The large quantity powdered dye discharge pipe 2 is a pipe having a large bore which extends outwardly from the tank wall and in which a helical or screw member 16 extends through the interior of the tank 1 and along the entire length of the large quantity powdered dye discharge pipe 2. The rear end of the helical or screw member 16 is fixedly secured to and supported by a rotating support shaft 8 which extends through the tank wall. Provided above the spiral or screw member 16 and the shaft 8 is a rotating shaft 6 which has a stirring blade mounted thereon and which passes through the tank wall and is supported so as to be slidably moved in the axial direction thereof. One end of the rotating shaft 6 is connected through a sliding-contact coupling to the operating end of a first air cylinder 14, whilst the other end thereof has fixedly secured thereto a bevel gear 12 fitted with a spur gear which meshes with the spur gear mounted on the above-mentioned rotating support shaft 8. With the piston rod within the first air cylinder 14 being extended outwardly, the bevel gear 12 having a spur gear mounted thereon is allowed to mesh with a bevel gear 10 mounted on the rotating drive shaft 5 so as to rotate the rotating shaft 6 fitted with a stirring blade, and also turn, through the intermeshing of the spur gears, the rotating support shaft 8 and the helical or screw member 16 fixedly secured thereto, so that the powdered dye stored in the storage tank 1 is subjected to a stirring action made by the stirring blade mounted on the rotating shaft 6 and also a quick powder delivery action caused by the turning of the helical or screw member 16 having a relatively large pitch within the powdered dye discharge pipe 2 having a relatively large bore thus discharging a large quantity of the powdered dye. Subsequently, when the piston rod in the first air cylinder 14 is withdrawn to its initial position, the bevel gear 12 is disengaged from the bevel gear 10 of the rotating drive shaft 5 to thereby stop the rotation of the shafts 6 and 8 and the turning of the herical or screw member 16.
The small quantity powdered dye discharge pipe 3 is smaller in bore than the large quantity powdered discharge pipe 2, and has a helical or screw member 17 inserted therein to cause powdered dye delivery action. With the exception that the helical or screw member 17 is smaller in diameter and pitch than the helical or screw member 16 and is capable of deliverying powdered dye with a higher accuracy than the former, powdered dye delivery action and the stoppage thereof provided by connection and disconnection between a rotating shaft 7 having a stirring blade mounted thereon, and a rotating support shaft 9, and also that between a bevel gear 11 mounted on the rotating drive shaft 4 and a bevel gear 13 due to actuation of a second air cylinder 15 can be made entirely in the same manner as aforementioned.
One embodiment of the method of weighing and taking out a powdered dye using the above-mentioned first apparatus will be described below.
The maximum error (P) of the accuracy of taking out powdered dye from the large quantity powdered dye discharge pipe 2 of this apparatus is ±0.5 gr., the maximum error of the accuracy of taking out powdered dye from the small quantity powdered dye discharge pipe 3 is ±0.35 gr., the measuring accuracy of the two electronic weighers is ±0.005 gr., and the maximum error of the liquid supply accuracy of the pump piping system is ±0.25 cc. The required quantity (a) of the powdered dye is input to a computor, not shown. If the value of required quantity of the dye is 9.36 gr., then the computor will output the value to the first weighing device 21, and at the same time command the fixed quantity delivery means associated with the large quantity powdered dye discharge pipe 2 of the storage tank 1 to deliver the powdered dye by an amount of 8 gr. which is less by one than the figure at the units place of the value of required quantity. If the weighted value (b) of the powdered dye received in the first dye container 19 is 8.5 gr., then the value (c) of difference of 0.86 gr. between the required quantity (a) and the weighed value (b) which needs to be supplemented is stored by the computor. Whilst, to cover the error range of the accuracy, the computor will command the fixed quantity delivery means associated with the small quantity powdered dye discharge pipe 3 to deliver the powdered dye by an amount of 1.56 gr. which equals to the value (c) of difference plus 0.7 gr. Then, the powdered dye discharged into the second dye container 20 is weighed by the second weighing device 22, and the weighed value is assumed to be 1.5 gr.. Subsequently, the computer will command the liquid supply pipe 25 to supply 750 cc of water to prepare diluted solution of 0.2%, and at the same time command the stirrer 26 to start to stir the solution, and then command the pump 31 in the pump piping system to transfer the diluted solution of 430 cc (including 0.86 gr. of the dye) into the first dye container 19 to thereby supplement the dye liquor with the accuracy of error range of ±0.25 cc. As a result, a dye liquor containing the dye of 9.36 ±0.0005 gr., error or deviation of which from the required quantity is extremely small, is obtained in the first dye container 19.
In the next place, an embodiment of the second apparatus of the present invention will be described below with reference to FIG. 5 which is a fragmentary front view showing the section of the principal parts thereof, and FIG. 6 showing the plan view thereof.
This apparatus comprises a plurality of unit devices having nearly the same arrangement as those of the above-mentioned first apparatus. This apparatus comprises a plurality of storage tanks 1, in which different kinds of powdered dyes are stored, and is arranged such that the aforementioned operations are made in turn and continuously every storage tank 1. The component parts of this apparatus having the same function as those of the afore-mentioned first apparatus are indicated with the same reference numerals. As already mentioned, this apparatus comprises a plurality of storage tanks 1, located in a row, and each of the tanks 1 has a large quantity powdered dye discharge pipe 2 projecting on one side of the row thereof and a small quantity powdered dye discharge pipe 3 projecting one the other side of the row thereof. Two guide rails 38 and 39 are mounted below the discharge pipes 2 and 3, respectively, and in parallel with the row of the storage tanks 1. Further, a first weighting device 21 which is an electronic weigher and a second weighting device 22 which is also an electronic weigher are arranged so that they may be moved on the guide rails 38 and 39, respectively. Both the weighting devices 21 and 22 are controlled such that they may be moved by transfer chains to positions opposite to a particular or any relevant storage tank 1 and stopped there.
The first weighting device 21 holds a first dye container 19 resting thereon, whilst the second weighing device 22 has a dish-shaped surface adapted to support and raise a second dye container 20 resting on a base 36 together the latter every dye storage tank 1. The base 36 is arranged to be moved up and down and loosely fitted in an opening formed in a rack 35. When the second weighing device is arranged to support and raise the container 20 together with the pedestal 36, it is ready for commencing its weighing operation.
A pump piping system 30 is provided independently for each of the dye storage tanks 1, and a liquid supply pipe 25 and a stirrer 26 are provided for each of the second dye containers 20.
By controlling the movement of the first and second weighing devices 21 and 22 to positions opposite to a particular one out of the powdered dye storage tanks 1 located in a row by a computor, and also by controlling the weighing and taking-out of the powdered dyes at respective tanks by the computor in the same manner as in the case of the aforementioned first apparatus, a required quantity of each of different kinds of powdered dyes stored in each of the storage tanks can be transferred or taken in the first dye container 19 with a minimum error or deviation.
It is a matter of course that in the case of the above operation the value of required quantity commanded by the computor to the first weighing device 21 is the total value of required quantities of different kinds of dyes.
Thus, the first dye container 21 in which the weighed and delivered dye is accommodated is transfered to a position where a diluted liquid supply pipe 45 and a dyeing aid supply pipe 46 are installed where the diluted liquid and the dyeing aid is added to the dye to prepare a desired dye liquor composition, which is then transported to a dyeing apparatus.
In the above-mentioned embodiment, if the conditions of the second apparatus controlled by the computor are changed, then a second method of the present invention can be carried out.
It is to be understood that the foregoing description is merely illustrative of preferred embodiments of the present invention, and that the scope of the invention is not to be limited, thereto, but is to be determined by the scope of the appended claims. | A method which enables a dye to be weighted and taken out quickly at a high accuracy regardless of the required quantity of the dye by taking out the greater part of the required quantity of the dye in a powdery state and the remaining quantity of the dye in the state of a diluted solution, upon taking out the required quantity of the powdered dye, and an apparatus suitable for carrying out the above-mentioned method. | 3 |
RELATED APPLICATIONS
This application is a continuation of application Ser. No. 10/623,433 filed Jul. 18, 2003 now U.S. Pat. No. 7,390,960, entitled Electronic Signal Processor, which is herein incorporated by reference in its entirety.
FIELD OF THE INVENTION
The present invention relates generally to electronic signal processors. More particularly, a preferred embodiment of the invention relates to altering or controlling the tonal qualities of electronic signals, such as audio signals, and related methods.
BACKGROUND OF THE INVENTION
Various prior art devices exist for modifying the tonal qualities of electronic signals. In audio frequency applications, the types of signals processed can be speech, musical instruments, synthesized waveforms, and the like. Prior art devices for processing musical instrument signals generally have a very limited ability to provide the musician with a variety of tonal qualities in the resulting sound. For example, prior art circuits exist for processing electric guitar signals that have a singular tonal quality, or “sound”. This is a serious limitation, since the guitarist must frequently employ a plurality of different circuits if different “sounds” are desired.
Some schemes exist in the art that include circuits with more than a singular sound. Usually this involves adding additional active circuits that the guitarist can activate, as desired. While such an arrangement can be successful, it also results in much greater total component count and added expense.
In addition, in some applications, it is desirable to deliberately add distortion to the sound to affect the tonal qualities. For example, deliberately adding distortion to the sound of an electric guitar began in the 1950's when rock music was becoming popular. At this time, the only techniques that an electric guitarist has to increase the amount of distortion into his sound was to increase the volume of a vacuum tube amplifier by (1) picking the strings of the guitar harder, (2) turning the volume of the guitar higher, or (3) turning the volume of the amplifier up; or some combination or variation of all three techniques. However, these techniques have the drawbacks that the guitarist usually could still not achieve the desired level of distortion, and/or high sound pressure levels were created that many people find uncomfortable or even distressing.
During the 1960's, the characteristic sound of an overdriven vacuum tube amplifier was realized while playing at lower volumes by using new types of circuits. These new circuits were frequently called “fuzzboxes” and were separate boxes that were external to the amplifier. Fuzzboxes typically employed a cascade or series connection of two or more transistor amplifier gain stages that had high input-to-output gain and that were easily overdriven by the output signal from the guitar. This provided a favorable increase in distortion and sustain to the guitar sound. However, it also introduced a new quality to the sound that is disliked by many guitarists. This quality is often referred to as the “solid-state sound” or the “transistor sound”. Either of these terms has acquired a very negative connotation to many guitarists. That is, the solid-state or transistor sound is quite different than the “tube sound”, which was developed by the overdriven vacuum tube amplifiers.
Many guitarists continue to believe that the best distortion sounds come from amplifiers that employ tube circuits. While the best solid-state amplifiers come close, they are frequently considered to be inferior to the tube amplifiers. Despite the many solid-state amplifiers that have been developed and introduced to the marketplace since the 1960's, the solid-state sound is still not on par with that of the tube amplifiers. Indeed, many different schools of thought exist on why there are differences in the sound and feel between the solid-state and tube amplifiers. Recent attempts to emulate the sound and feel of tube amplifiers have stagnated.
It has been an objective in the guitar industry for many years to develop solid-state amplifiers that have the sound and feel of the overdriven tube amplifier. “Feel” indicates that a tube amplifier also has a certain tactile quality when overdriven. Many guitarists think that the tube amplifiers respond to the guitarists “touch”, including their picking techniques and playing style, better than the solid-state amplifiers. In this respect, it is frequently stated that tube amplifiers are very touch sensitive.
There has been a long-felt need for a solid-state amplifier or signal processor that emulates the sound and feel of an overdriven vacuum tube amplifier.
A need also exists for a signal processor that emulates the sound of an overdriven vacuum tube amplifier in which the tone may be adjusted or customized to the user's desires.
Accordingly, it is a general object of the present invention to provide a new and improved signal processor that emulates the sound and feel of an overdriven vacuum tube amplifier.
Another object of the present invention is to provide a signal processor of the solid-state type that emulates the desired performance characteristics of a tube amplifier.
Yet another object of the present invention is to provide a signal processor with sound characteristics that may be adjusted to the user's tastes.
A further object of the present invention is to filter the lower frequency input signals with a second order or third order high pass filter before amplification of the input signals to reduce lower frequency intermodulation distortion when the amplifier is overdriven.
A still further object of the present invention is to provide at least two individual gain controls with overlapping gain characteristics that may be switched to provide selectable gain of those frequencies in the passband of the input filter.
Another object of the present invention is to provide related methods of filtering an input signal with an input filter of the second or third order high pass type to substantially reduce lower frequency intermodulation distortion in the signal processor.
BRIEF SUMMARY OF THE INVENTION
This invention is directed to an electronic signal processor that has improved ability to alter the tonal characteristics of an audio frequency input signal and to reduce lower frequency intermodulation distortion. The signal processor may have a buffer stage to receive the input signal and to provide an input signal with low output impedance to the first filter of the signal processor.
A first filter is preferably a second or third order high pass filter with a frequency response curve of 12 db/octave slope or 18 db/octave slope for the lower frequencies, respectively. One of the purposes of the first filter is to substantially reduce lower frequency intermodulation distortion by means of such filtering. The first filter also has at least some user-selectable corner frequencies in its frequency response curve so that the user may customize the tonal quality of the signal processor. The first filter preferably also includes at least two adjustable gain levels with overlapping gain characteristics that may be pre-set by the user and that may be alternately selected. The multiple, user-preset, selectable gain levels allow the user to adjust the amount of distortion present in, and therefore the tonal color of, the processor output.
The output of the first filter is input to one or more limiting gain stages, which are in series or cascade configuration. These gain stages can increase the amount of distortion present in the processor output. Oppositely poled diodes in the feedback circuits of the amplifiers in the gain stages limit the output amplitude of the amplifiers and contribute to the distortion characteristics of the signal processor. Preferably, the gain stages have an additional or second feedback circuit that introduces a controlled amount of hysteresis, a nonlinear distortion, in the amplification characteristic of the gain stages. Thus, when the gain stages are overdriven by the input signal, the clipping or distortion in the output signal of the gain stages will be enhanced.
The present invention also relates to amplifiers with two feedback loops for use in the gain stages of signal processors. The first feedback loop includes a resistor, a capacitor and at least two diodes, with the diodes oppositely poled between the output of the amplifier and its inverting input. The second feedback circuit includes at least one resistor and at least one capacitor coupled between the output of the amplifier and the input of the gain stage. A resistor preferably couples the second feedback loop to the inverting input of the amplifier. The two feedback loops interact to enhance the distortion when the amplifier is overdriven by an input signal.
The output from the gain stages is input to a second filter, which is of the low pass type and preferably of the second order low pass type. The output the second filter is provided as the output of the signal processor.
Related methods of processing an input signal that includes a band of frequencies to reduce lower frequency intermodulation distortion includes filtering the input signal with the first filter of the second or third order type, supplying the filtered signal to the gain stages, amplifying the filtered signal in the gain stages, supplying the amplified signal to a second filter of the low pass type, filtering the amplified signal in the second filter, and supplying the signal from the second filter as the output signal of the signal processor. The methods also include changing at least some of the corner frequencies in the frequency response curve of the first filter to change or customize the frequency response of the first filter. The methods further include selecting one of the two gain controls in the first filter.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with the further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several figures in which like reference numerals identify like elements, and in which:
FIG. 1 is a block diagram of the signal processor of the present invention;
FIG. 2 is a schematic circuit diagram of a preferred embodiment of the signal processor of the present invention;
FIG. 3 is a schematic circuit diagram of a preferred embodiment of an input filter for the signal processor shown in FIGS. 1 and 2 ;
FIG. 4 is a frequency response curve of the input filter of the block diagram shown in the schematic circuit diagram of FIG. 3 under selected circuit conditions;
FIG. 5 is a frequency response curve of the input filter shown in the schematic circuit diagram of FIG. 3 under selected circuit conditions;
FIG. 6 is a frequency response curve of the input filter shown in the schematic circuit diagram of FIG. 3 under selected circuit conditions;
FIG. 7 is a frequency response curve of the input filter shown in the schematic circuit diagram of FIG. 3 under selected circuit conditions;
FIG. 8 is a schematic circuit diagram of a preferred embodiment of an amplifier stage for the signal processor shown in FIG. 2 ;
FIG. 9 is a schematic circuit diagram of an alternate embodiment of an amplifier stage for the signal processor shown in FIG. 2 ;
FIG. 10 is a frequency response curve of the amplifier stages shown in the schematic circuit diagrams of FIGS. 8 and 9 ;
FIG. 11 is a schematic circuit diagram of an output filter for the signal processor shown in FIG. 1 ;
FIG. 12 is a frequency response curve of the output filter shown in the schematic circuit diagram of FIG. 11 under selected circuit conditions;
FIG. 13 is a block diagram that is related to the block diagram of FIG. 1 , but with the preferred frequency responses of the first and second filters inserted in the respective filter blocks;
FIG. 14 is an alternate embodiment of the frequency response curve for the first filter k 1 shown in the block diagram of FIG. 1 ; and
FIG. 15 is an alternate embodiment of the frequency response curve for the second filter k 2 shown in the block diagram of FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
The present invention of a signal processing circuit, generally designated 40 , is shown in block diagram format in FIG. 1 . An input signal is received at an input terminal 41 to a small magnitude output impedance stage 43 . Stage 43 preferably has an output impedance that is significantly smaller than the input impedance of a first filter k 1 44 so as not to materially affect the corner frequencies of the first filter 44 . First filter 44 is a complex filter with multiple user-adjustable corner frequencies and passband gains. The output of filter 44 is input into a first gain stage 45 . The output of the first gain stage 45 is input into a second gain stage 46 . The output of the second gain stage 46 is input into a second filter k 2 47 , which provides the output signal of the signal processing circuit 40 at a terminal 42 .
A preferred schematic for the signal processor circuit 40 is shown in FIG. 2 with the blocks identified in FIG. 1 shown in dashed lines about certain components of the schematic diagram. The design and operation of circuit 40 will now be further considered in its various portions corresponding to the blocks 43 - 47 shown in FIGS. 1-2 .
In general an input signal, such as from a guitar, is buffered by the low output impedance stage 43 before presentation to the first filter 44 . For example, as shown in FIG. 2 , the low output impedance stage 43 may consist of an amplifier 50 that is configured for unity gain. While not shown in block 43 of FIG. 2 , it may also be desirable to provide low pass filtering at the input terminal 41 . For example, frequencies above the audio band, such as radio frequency interference (RFI) or the like, may be attenuated at or near the input to amplifier 50 .
First filter 44 shown in FIG. 3 provides filtering of the low frequencies in the audio frequency range to prevent the generation of significant amounts of low frequency intermodulation (IMD) signals, which may result from the subsequent amplification by the first and second gain stages 45 and 46 . First filter 44 receives its input signal from the output of the low impedance stage 43 at an input terminal 51 . A resistor 52 and a capacitor 53 , connected in series, receive signals present on input terminal 51 . An opposite terminal of capacitor 53 is referenced to ground by a resistor 54 .
A single pole, multiple throw switch 55 , which may be a rotary switch with n positions, is connected to capacitor 53 and resistor 54 . Switch 55 selects one of n capacitors, such as capacitors 56 - 63 in the example shown in FIG. 5 . Opposite ends of capacitors 56 - 63 are connected to a common node 65 .
A double pole, double throw switch 75 selects one of two networks that are also connected to node 65 . In the position shown in FIG. 3 , switch 75 selects the first network that includes a pair of resistors 66 and 68 . Resistor 68 may be in the form of an adjustable resistor or potentiometer with an adjustable terminal 67 to control the amplitude of the signals provided through filter 44 . If switch 75 is in the opposite position from that shown in FIG. 3 , the second network consisting of resistor 70 , capacitor 69 and variable resistor or potentiometer 73 is selected. This second network also provides control of the amplitude of the signals provided through filter 44 by varying the position of the adjustable terminal 72 of variable resistor 73 . In addition, capacitor 69 provides some additional filter effects over that of the first network consisting of resistors 66 and 68 .
Whichever network is selected by switch 75 provides the signals though the series connection of a capacitor 76 and a resistor 77 to the inverting input of an operational amplifier 80 . Op amp 80 has its non-inverting terminal referenced to ground. Op amp 80 also has a pair of diodes 81 and 82 oppositely poled between the output terminal and the inverting terminal of op amp 80 to keep op amp 80 from being overdriven. A resistor 84 and a capacitor 83 are also connected as feedback components, in parallel with diodes 81 - 82 , between the output terminal and inverting terminal of op amp 80 . Op amp 80 also provides the output signal of first filter 44 at an output terminal 85 .
First filter 44 provides different rates of signal gain or attenuation over different frequency ranges. In the illustrated embodiment of first filter 44 , there are four corner frequencies f 1 , f 2 , f 3 and f 4 , where each corner frequency is defined by the known equation f=1/(2πRC) and where R is the effective resistance at the frequency of interest, C is the effective capacitance at the frequency of interest and π is the well-known value of 3.1415 . . . .
FIGS. 4 through 7 illustrate the different effects that are provided by the first filter 44 . While FIGS. 4-7 , 10 and 12 do not have a scale along the frequency axis, it will be understood that these frequency response charts generally cover the frequency range of about 0 Hz to 20 KHz, which includes the audio frequency range, which is often specified as 20 Hz to 20 KHz. As will be presented more fully below, the frequency response of the first filter 44 depends upon which of capacitors 56 - 63 is selected by switch 55 , the first or second network selected by switch 75 , and the position or adjustment selected for potentiometers 68 or 73 . Irrespective of these selections, the gain versus frequency graphs shown in FIGS. 4-7 will, in general, have a slope of 18 db/octave in a first frequency band from 0 Hz to f 1 , 12 db/octave in a second frequency band from f 1 to f 2 , 6 db/octave in a third frequency band from f 2 to f 3 , 0 db/octave in a fourth frequency band (which may also be referred to as a passband) from f 3 to f 4 , and −6 db/octave for frequencies above f 4 .
Filters, such as the first filter 44 that exhibits a slope of 18 db/octave in the lower frequency ranges and a passband of 0 db/octave in the higher frequency ranges are also known in the art as third order high pass filters. In the example of FIG. 6 , there is additionally a high frequency rolloff of −6 db/octave above the corner frequency f 4 . Thus, a filter with the frequency response curve shown in FIG. 4 could also be referred to as a third order high pass filter with high frequency rolloff.
FIG. 4 illustrates the effects of varying the passband gain with potentiometers 68 or 73 , depending upon which of the networks is selected by switch 75 . In frequency response graph 130 , the gain is set higher than in the graph 131 . Of course, if potentiometer 68 is set at for a higher gain value than potentiometer 73 , the user may switch from higher to lower gain (and, hence, from higher to lower volume) by changing switch 75 from the position shown in FIG. 3 to the opposite position, and vice versa. To this end, switch 75 may be a foot-operated switch. As illustrated in FIG. 4 , the changes in gain tend to have greater affect on those frequency bands that are less attenuated, such as those frequencies that lie between f 2 to beyond f 4 . If either of potentiometers 68 , 73 are adjusted by moving the adjustable terminal 67 or 72 to its lower most position, the signal will be completely attenuated since lower pole of switch 75 is referenced to ground. Thus, potentiometers 68 , 73 provide a broad range of signal attenuation.
FIG. 5 illustrates the ability to change the gain characteristics of those portions of the frequency response curve below frequency f 3 , including the frequency of the corner frequency f 3 . This is accomplished by changing the position of switch 55 to select one of capacitors 56 - 63 . Capacitors 56 - 63 are selected to be of different capacitive values to provide different frequency response characteristics. FIG. 5 shows three different frequency response graphs 132 - 134 for three different capacitive values. Of course, with n capacitors of different capacitive value, n different frequency response curves will result instead of the three shown in FIG. 5 . Note also that changing the capacitive value with switch 55 will also affect the corner frequency f 3 . In the example shown, corner frequency f 3 a is associated with frequency response curve 132 , corner frequency f 3 b is associated with frequency response curve 133 and corner frequency f 3 c is associated with frequency response curve 134 . In general, a lower capacitive value for one of the capacitors 56 - 63 will cause the corner frequencies f 1 , f 2 and f 3 to shift toward higher frequencies. For example, in order to provide a range of effects through the selection of one of the n capacitors with switch 55 for audio signal applications, the capacitor with the lowest value preferably moves the 12 db/octave slope up to about 4 to 5 KHz. On the other hand, the capacitor with the highest capacitive value selected by switch 55 preferably moves the 12 db/octave slope down to about 30 Hz. Thus, the lower frequencies that the 12 db/octave portion of the frequency response curve operates on can range from about 30 Hz to about 5 KHz. The actual selection will depend upon the preferences of the user.
FIG. 6 illustrates the ability to change the gain characteristics of that portion of the frequency response curve above the corner frequency f 4 . The feedback components, capacitor 83 and resistor 84 , across op amp 80 normally determine the frequency of corner frequency f 4 a when switch 75 is in the position shown in FIG. 3 . This results in the frequency response graph shown by graph 136 . However, when switch 75 is in the opposite position to that shown in FIG. 3 , capacitor 69 will change the frequency response to a graph such as graph 135 in FIG. 6 . Note that in graph 135 , capacitor 69 also causes an increase in the corner frequency f 4 b above that of f 4 a , and an increase in the higher frequency gain above that of graph 136 .
FIG. 7 is a composite of the frequency response graphs of FIGS. 4-6 . The frequency shifts of some of the corner frequencies have not been illustrated, as in FIGS. 4-6 , for purposes of simplifying this composite graph. It will thus be appreciated that the above-described differing techniques for customizing the frequency response characteristics of the first filter 44 provide the ability to customize or fine tune any portion of the audio frequency spectrum, as desired by the user.
The preferred embodiment of an amplifier for the first gain stage 45 in FIG. 3 is shown in FIG. 8 . An input terminal 88 of the first gain stage 45 passes input signals through a resistor 89 and a capacitor 90 to a node 97 . Node 97 is connected via a feedback resistor 91 to the output terminal of an op amp 98 and via a resistor 96 to the inverting input of op amp 98 . The non-inverting input of op amp 98 is referenced to ground. Feedback components, including a capacitor 94 and a resistor 95 , are connected from the inverting input to the output of op amp 98 . Oppositely poled diodes 92 and 93 , also connected from the inverting input to the output of op amp 98 , keep the op amp output amplitude limited. Diodes 92 - 93 clip symmetrically and therefore tend to limit the amount of distortion when the op amp 98 is overdriven. Diodes 92 - 93 also tend to provide some nonlinear distortion such as hysteresis when op amp 98 is overdriven since the feedback capacitor 94 will be charged by conduction of diodes 92 - 93 . However, when diodes 92 - 93 become non-conductive, the impedance seen by feedback capacitor 94 increases and capacitor 94 takes longer to discharge. Thus, the first feedback circuit consisting of diodes 92 - 93 , capacitor 94 and resistor 95 operates in two different impedance modes, depending upon whether diodes 92 - 93 are conductive or non-conductive.
The amplifier embodiment of FIG. 8 has superior performance characteristics when used in signal processors for guitars. It is desirable for the best tonal characteristics resulting from clipping caused by gain stage 45 , when overdriven, that the clipping not be symmetrical. To this end, a second feedback circuit, consisting of resistors 89 and 91 and capacitor 90 , creates additional nonlinear distortion such as hysteresis in the response of the gain stage 45 . Resistor 96 provides some interaction between the first feedback circuit consisting of resistor 95 , capacitor 94 and diodes 92 - 93 , and the second feedback circuit. This additional nonlinear distortion such as hysteresis provides further distortion of the input signal by gain stage 45 when the op amp 98 is overdriven.
A simplified gain stage, generally designated 48 , is shown in FIG. 9 , may be used in place of the gain stage 45 of FIG. 8 , if desired. Simplified gain stage 48 is similar in structure and operation to gain stage 45 , except that resistors 91 and 96 of gain stage 45 that form a portion of an additional feedback loop about op amp 98 in FIG. 8 are eliminated. Thus, the operation of gain stage 48 is similar in operation to the op amp 80 in the first filter 44 , as described above.
The gain stages employed in the second gain stage 46 in FIG. 1 are preferably similar to those used in the first gain stage, and as shown in FIG. 8 or FIG. 9 . However, the second gain stage may have pairs of diodes 104 - 105 and 106 - 107 oppositely poled across the op amp 112 as shown in the complete schematic of FIG. 2 to allow for greater amplitude signals before the diodes 104 - 107 become operative and limit the output amplitude.
Second gain stage 46 is connected in series or cascade with the first gain stage 45 . Each of gain stages 45 , 46 preferably has a gain of greater than one and is nominally inverting. The frequency response for gain stages 45 or 46 is shown by a graph 137 in FIG. 10 , and has a lower corner frequency f 1 and a higher corner frequency f 1 . From 0 Hz to f 1 , the slope is 6 db/octave. From f 1 to fh, which is the passband, the slope is 0 db/octave. At frequencies above fh, the slope is −6 db/octave.
The second filter stage, generally designated 47 , is shown in FIG. 11 . An input terminal 116 receives input signals from the output terminal of the second gain stage 46 . Input terminal 116 is connected via a resistor 117 and capacitor 118 to a node 122 . A resistor 119 and a capacitor 120 are connected in series between node 122 and ground. Node 122 is also connected via a resistor 121 to another node 127 . A resistor 123 and a capacitor 124 are connected in series between node 127 and ground. Also separately connected in parallel between node 127 and ground are a capacitor 125 and a potentiometer 126 . The variable wiper arm of potentiometer 126 is connected to the output terminal 42 of the signal processor 40 of FIG. 2 . Potentiometer 126 may function as the volume control for the signal processor.
The second filter 47 may have a complex frequency response as shown by the graph 138 in FIG. 12 . Graph 138 may have six positive corner frequencies, f 5 , f 6 , f 7 , f 8 , f 9 and f 10 , in order of increasing frequency. From 0 Hz to corner frequency f 5 , the slope is 6 db/octave; from corner frequency f 5 to corner frequency f 6 , the slope is 0 db/octave; from corner frequency f 6 to corner frequency f 7 , the slope is −6 db/octave; from corner frequency f 7 to corner frequency f 8 , the slope is −12 db/octave; from corner frequency f 8 to corner frequency f 9 , the slope is −6 db/octave; from corner frequency f 9 to corner frequency f 10 , the slope is 0 db/octave; and above corner frequency f 10 , the slope is −6 db/octave. Capacitor 118 creates the low frequency rolloff below corner frequency f 5 , and capacitor 125 creates the high frequency rolloff above corner frequency f 10 .
FIG. 13 is a block diagram that is related to the block diagram shown in FIG. 4 , but with the preferred frequency responses of the first and second filters 44 , 47 shown in the filter blocks. In addition, the two gain stages 45 - 46 are shown combined in FIG. 13 into a single stage. While preferred embodiments of the circuitry for the filters 44 , 47 have been presented above in FIGS. 3 and 11 , it will be appreciated by those skilled in the art that these filters could be active or passive and provide the desired frequency response curves. In accordance with one aspect of the present invention, at least 12 db/octave is used in the lower frequencies of the audio spectrum to provide greater attenuation of the lower audio frequencies. This helps minimize the production of lower frequency intermodulation distortion (IMD) frequency products, as previously discussed above, by the significant gain of the gain stages 45 - 46 . This avoids the commonly known muddy sound produced by prior art amplifiers.
The gain stages 45 - 46 may be combined into a single gain, or constitute a plurality of individual gain stages coupled together in the known cascade configuration.
The distortion produced may be modified by providing some offset voltage to the operational amplifiers, such as by referencing the non-inverting inputs to op amps 98 and 112 in FIGS. 2 and 8 - 9 to a reference (bias) voltage instead of to ground. Such use of bias voltage may be necessary if the op amps have unequal positive and negative supply voltages. These op amps 98 and 112 operate linearly so long as they are not overdriven. As previously discussed, if the op amps 98 and 112 are overdriven, the feedback diodes 92 - 93 and 104 - 107 will be rendered conductive. Thus, in the preferred embodiment of the invention, non-linearity of the gain stages results when these normally nonconductive diodes become conductive. These non-linearities may be modified, if desired, by offset biasing of the op amps 98 and 112 , such as by biasing the non-inverting inputs at a nonzero reference voltage.
An alternative frequency response curve 141 is shown in FIG. 14 for the first filter 44 , instead of the frequency responses shown in FIGS. 4-7 . In this embodiment, frequency response curve 141 has a slope of 12 db/octave at the lowest frequencies instead of 18 db/octave below the corner frequency f 1 in FIGS. 4-7 . Curve 141 also does not have the high frequency rolloff of −6 db/octave for the higher frequencies, such as above the corner frequency f 4 in FIGS. 4-7 . Characteristics of curve 141 can be provided by eliminating capacitors 53 and 83 in the schematic of filter 44 in FIG. 3 . For example, short circuiting of capacitor 53 will eliminate the additional 6 db/octave of slope at the lowest frequencies of interest, thereby also eliminating the corner frequency f 1 . Elimination of capacitor 83 will also eliminate the corner frequency f 4 in FIGS. 4-7 and the −6 db/octave rolloff for frequencies above f 4 . However, since capacitor 83 also contributes to the stability of op amp 80 , it may be desirable to simply decrease the capacitive value of capacitor 83 such that the corner frequency f 4 is above the frequencies of interest, and which effectively increases the passband of 0 db/octave slope. A first filter 44 with the frequency response characteristics of FIG. 14 , instead of with the frequency response characteristics of FIGS. 4-7 , will provide sufficient attenuation of the lower frequencies prior to amplification by the gain stages 45 - 46 to minimize IMD frequency products in many applications.
An alternative frequency response curve 142 is shown in FIG. 15 for the second filter 47 , instead of the frequency response curve 138 shown in FIG. 12 . In this embodiment, frequency response curve 142 has a slope of 0 db/octave at the lowest frequencies instead of 6 db/octave below the corner frequency f 5 in FIG. 12 . Curve 142 also does not have the high frequency rolloff of −6 db/octave for the higher frequencies, such as above the corner frequency f 10 in FIG. 12 . A filter having the frequency response curve shown in FIG. 15 is known as a low pass filter. If the slope above the low frequencies is −12 db/octave for n=2, the filter may be referred to as a second order low pass filter.
The frequency response curve 138 in FIG. 12 may be easily modified to resemble the frequency response curve 142 in FIG. 15 by eliminating the low frequency rolloff capacitor 118 from the schematic shown in FIG. 11 and by eliminating the high frequency rolloff capacitor 125 . This will also eliminate the corner frequencies f 5 and f 10 shown in FIG. 12 . Alternately, capacitor 125 may be decreased in value such that the corner frequency f 10 is moved to a higher frequency beyond the frequency range shown in FIG. 12 .
While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made therein without departing from the invention in its broader aspects. | An electronic signal processor for processing signals includes a complex first filter, one or more gain stages and a second filter. The first filter is characterized by a frequency response curve that includes multiple corner frequencies, with some corner frequencies being user selectable. The first filter also has at least two user-preset gain levels which may be alternately selected by a switch. Lower frequency signals are processed by the first filter with at least 12 db/octave slope, and preferably with 18 db/octave slope to minimize intermodulation distortion products by subsequent amplification in the gain stages. A second filter provides further filtering and amplitude control. The signal processor is particularly suited for processing audio frequency signals. Related methods include filtering the input signal with an input filter of the second or third order high pass type, amplifying the filtered signal and further filtering the amplified signal with a low pass filter, which may be of the second order type. | 7 |
FIELD OF INVENTION
[0001] The present invention relates to a photovoltaic power circuit, such as a solar cell battery, in particular to a photovoltaic power circuit comprising analog devices, which has a much simpler structure than conventional digital photovoltaic power circuit.
BACKGROUND OF THE INVENTION
[0002] More and more advanced countries are devoting research resources to solar cell batteries, in view of energy crisis. Solar cell batteries belong to the family of photovoltaic power circuits. A photovoltaic power circuit functions by means of the characteristics of semiconductor PN junctions. The PN junctions transfer the received photo energy to electric energy, and charge a battery with the electric energy so that it can generate power. FIG. 1 shows the V-I (voltage-current) relationship for a PN junction diode to generate electric energy, in which the solid line represents the relationship between voltage and current, and the dot line represents the product of voltage and current (V*I), i.e., power. The figure shows only one curve because it is assumed that the received photo energy remains unchanged, If the received photo energy changes, the curve correspondingly changes.
[0003] As shown by the curve in FIG. 1 , the maximum voltage point Voc is at the open circuit point, while the maximum current point Isc is at the short circuit point. However, the maximum power output point is neither at the maximum voltage point nor at the maximum current point, but at a maximum power point MPP, with corresponding optimum voltage Vmpp and optimum current Impp. Because the received photo energy often keeps varying, prior art digital photovoltaic power circuits have to make complicated calculation, by sophisticated digital circuit, to extract the electric energy at the MPP corresponding to the received photo energy.
[0004] An example of such prior art digital photovoltaic power circuit is disclosed in U.S. Pat. No. 6,984,970, which is shown in FIG. 2 in a simplified form. The voltage Vin generated by a photovoltaic device 2 is converted to output voltage Vout by a power stage 3 , to be supplied to a load 4 . The load 4 for example can be a charging battery, and the power stage 3 for example can be a boost converter, a buck converter, an inverter, a fly-back converter, etc. To keep the power stage 3 extracting electric energy at the MPP, a digital controller 5 is provided in the circuit, which includes a digital calculation module 51 (e.g., a digital microcontroller) that keeps multiplying the value of the voltage Vin with the value of the extracted current I to obtain the MPP, and further calculates the optimum voltage Vmpp based on the obtained MPP. The calculated voltage Vmpp is compared with the input voltage Vin, and the comparison result drives a controller circuit 52 to control the power stage 3 . The digital controller 5 shown in FIG. 2 is very sophisticated; it requires a huge number of transistors, and it requires analog-to-digital converters (ADC) to capture voltage and current signals. Inevitably, this increases difficulties and cost of the circuit and its design.
[0005] Another prior art digital photovoltaic power circuit is disclosed in US Patent Publication No. 2006/0164065. This prior art only briefly explains the idea that the circuit includes a search mode and a dithering mode. In the initial search mode, the circuit sweeps the voltage-current curve to find the MPP; thereafter, it enters the dithering mode in which it operates according to the current value corresponding to the MPP, and periodically samples and updates the vale (for details, please refer to paragraphs 0008, 0010, 0033 and FIG. 5 of the patent publication). However, this cited patent publication does not explain how it “sweeps” to find the MPP.
[0006] Although there is no detailed circuit structure illustrating how it sweeps, it can be seen from the description relating to the search mode and the sweeping process that this cited patent publication, even if it does not require multiplication of multiple voltage and current values (in fact one can not see how it omits such complicated calculation from the specification of this cited patent publication), requires many digital circuits such as memories or registers and comparators; otherwise it can not select and memorize the maximum power point MPP. In addition to the complexity of the circuit, the sweeping process proposed by this cited patent publication occupies effective operation time of the circuit. Moreover, if light intensity changes after initialization, causing the photovoltaic device to deviate from the original voltage-current curve, the circuit has to reinitiate the search mode with the sweeping process, which is very inefficient.
[0007] In brief, US Patent Publication No. 2006/0164065 requires a complicated circuit and an inefficient process to find the MPP point, so that it can operate in the dithering mode in an analogous manner. Obviously this is disadvantageous.
SUMMARY OF THE INVENTION
[0008] In view of the foregoing, it is desirous, and thus an object of the present invention, to provide an analogue photovoltaic power circuit that improves the drawbacks in prior art.
[0009] To achieve the above and other objects, in one aspect of the present invention, an analog photovoltaic power circuit, comprising: a primary photovoltaic device group for receiving photo energy and generating an input voltage; a power stage for converting the input voltage to an output voltage; an optimum voltage point estimation circuit for estimating an optimum voltage point according to a ratio of the open circuit voltage of the primary photovoltaic device group; and an analog comparison and control circuit for controlling the conversion operation of the power stage according to a comparison between the optimum voltage point estimated by the optimum voltage point estimation circuit and the input voltage.
[0010] In the above-mentioned aspect of the present invention, the ratio is preferably about 70% to about 90% of the open circuit voltage, such as 80%. Because the optimum voltage point is obtained from a ratio of the open circuit voltage of the primary photovoltaic device group, it is not required to use a sophisticated digital calculation circuit, nor any sweeping process.
[0011] In another aspect of the present invention, an analog photovoltaic power circuit comprises: a primary photovoltaic device group for receiving photo energy and generating an input voltage, the input voltage corresponding to an input current; a power stage for converting the input voltage to an output voltage; an optimum voltage point estimation circuit receiving a predetermined voltage and estimating an optimum voltage point according to (1) a direction of variation of the input voltage and a direction of variation of the power generated by the primary photovoltaic device group, or (2) a direction of variation of the input current and a direction of variation of the power generated by the primary photovoltaic device group; and an analog comparison and control circuit for controlling the conversion operation of the power stage according to a comparison between the optimum voltage point estimated by the optimum voltage point estimation circuit and the input voltage.
[0012] In the above-mentioned aspect of the present invention, it is not required to precisely calculate the maximum power point at the initialization stage; the initial value of the optimum voltage point can start from a rough starting point. The rough starting point can be a divisional voltage from a predetermined voltage obtained by a simple voltage divider circuit. The predetermined voltage can be a fixed voltage, or obtained from the primary photovoltaic device group, or obtained from a reference photovoltaic device group, without any sophisticated calculation. Furthermore, it is not required to precisely calculate the power generated by the primary photovoltaic device group, but only required to know the direction of its variation. Hence, a very simple power meter, or a simple power trend meter that only estimates the trend of the power changes (that the power is increasing or decreasing) is sufficient. In some cases, it is sufficient to use even a current sensing circuit, and use the current value sensed by the circuit to represent power.
[0013] In yet another aspect of the present invention, a method for extracting energy from a photovoltaic device group comprises the steps of: providing a reference voltage of about 70% to about 90% of an open circuit voltage of the photovoltaic device group; comparing an output voltage of the photovoltaic device group with the reference voltage, to control the output voltage of the photovoltaic device group substantially at the reference voltage; and extracting energy from the photovoltaic device.
[0014] In still another aspect of the present invention, a method for calculating an optimum voltage point of a photovoltaic device group comprises the steps of: providing a predetermined initial value of a reference voltage; estimating a direction of variation of the output voltage of the photovoltaic device group; estimating a direction of variation of the output power of the photovoltaic device group; comparing the two directions, and increasing the reference voltage when both directions are the same, and decreasing the reference voltage when both directions are opposite; and using the adjusted reference voltage as the optimum voltage point.
[0015] In yet another aspect of the present invention, a method for calculating an optimum voltage point of a photovoltaic device group comprises the steps of: providing a predetermined initial value of a reference voltage; estimating a direction of variation of the output current of the photovoltaic device group; estimating a direction of variation of the output power of the photovoltaic device group; comparing the two directions, and decreasing the reference voltage when both directions are the same, and increasing the reference voltage when both directions are opposite; and using the adjusted reference voltage as the optimum voltage point.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings.
[0017] FIG. 1 shows the voltage-current relationship for a photovoltaic device under the same photo energy.
[0018] FIG. 2 is a schematic circuit diagram showing a prior art photovoltaic power circuit.
[0019] FIG. 3 is a schematic circuit diagram showing a first embodiment according to the present invention.
[0020] FIG. 4 is a schematic circuit diagram showing a second embodiment according to the present invention.
[0021] FIG. 5 is a schematic circuit diagram showing a third embodiment according to the present invention.
[0022] FIG. 6 is a schematic circuit diagram showing a fourth embodiment according to the present invention.
[0023] FIG. 7 is a schematic circuit diagram showing a fifth embodiment according to the present invention.
[0024] FIG. 8 is a schematic circuit diagram showing a sixth embodiment according to the present invention.
[0025] FIG. 9 is a schematic circuit diagram showing a seventh embodiment according to the present invention.
[0026] FIG. 10 is a schematic circuit diagram showing an eighth embodiment according to the present invention.
[0027] FIG. 11 is a schematic circuit diagram showing a ninth embodiment according to the present invention.
[0028] FIG. 12 is a schematic circuit diagram showing a tenth embodiment according to the present invention.
[0029] FIG. 13 is a schematic circuit diagram showing an eleventh embodiment according to the present invention.
[0030] FIG. 14 is a schematic circuit diagram showing a twelfth embodiment according to the present invention.
[0031] FIG. 15 shows an example of a current sensing circuit.
[0032] FIG. 16 is a schematic circuit diagram showing a thirteenth embodiment according to the present invention.
[0033] FIG. 17 is a schematic circuit diagram showing a fourteenth embodiment according to the present invention.
[0034] FIG. 18 is a schematic circuit diagram showing a fifteenth embodiment according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0035] The key feature of the present invention is that it uses analog circuit devices, which are much simpler than the devices in prior art, to calculate the maximum power point MPP in a photovoltaic power circuit. The circuit according to the present invention is thus called “analog photovoltaic power circuit”. However, it should be understood that the term “analog photovoltaic power circuit” only means that the key functions of the circuit are achieved by analog devices; it does not mean that all of the circuit devices are analog devices.
[0036] In general, the optimum voltage Vmpp is about 70% to about 90% of the open circuit voltage Voc. Thus, in the first concept of the present invention, the optimum voltage Vmpp is estimated as about 70% to about 90% of the open circuit voltage Voc of the photovoltaic power circuit.
[0037] Referring to FIG. 3 , it is a schematic circuit diagram showing a first embodiment according to the present invention. In this embodiment, Vmpp is estimated as about 80% of Voc (wherein the number 80% is for illustrative purpose; it can be any number). As shown in the figure, this embodiment includes a primary photovoltaic device group 21 and a reference photovoltaic device group 22 . The primary photovoltaic device group 21 generates electric energy, while the reference photovoltaic device group 22 serves to estimate the optimum voltage Vmpp. The voltage generated by the primary photovoltaic device group 21 is supplied to a power stage 3 as its input voltage Vin; the power stage 3 for example can be a boost converter, a buck converter, an inverter, a fly-back converter, etc. The power stage 3 is controlled by an analog comparison and control circuit 50 , to lock Vin at the MPP, and to receive energy from its input terminal, by a manner below.
[0038] The reference photovoltaic device group 22 generates a reference voltage VinREF. Because the reference photovoltaic device group 22 corresponds to a very small load, the reference voltage VinREF is about equal to the open circuit voltage of the reference photovoltaic device group 22 . The reference photovoltaic device group 22 is proportional to the primary photovoltaic device group 21 , that is, the number or size of its devices is so arranged that the open circuit voltage of the reference photovoltaic device group 22 is about equal to, or is a ratio of the open circuit voltage Voc of the primary photovoltaic device group 21 . The resistors R 1 and R 2 divide the reference voltage VinREF so that the voltage at the node VR is about equal to 80% of the open circuit voltage Voc of the primary photovoltaic device group 21 , i.e., the estimated Vmpp.
[0039] Preferably, the voltage at the node VR and the input voltage Vin are compared in the analog comparison and control circuit 50 , and the comparison result controls the power stage 3 to receive energy from its input terminal. When the input voltage Vin is larger than the voltage at the node VR, the power stage 3 extracts more current from its input terminal; when the input voltage Vin is smaller than the voltage at the node VR, the power stage 3 reduces current it extracts from its input terminal. According to the voltage-current curve shown in FIG. 1 , when current increases, the output voltage of the primary photovoltaic device group 21 decreases, that is, the input voltage Vin decreases. On the other hand, when current decreases, the output voltage of the primary photovoltaic device group 21 increases, that is, the input voltage Vin increases. Thus, by mechanism of comparison and feedback control, the input voltage Vin will be locked at the voltage at the node VR, so that the input voltage Vin is at the estimated Vmpp. In this way, the power stage 3 works at its optimum operation point, to receive maximum energy.
[0040] The analog comparison and control circuit 50 can be embodied by a very simple linear regulator, as referring to the second embodiment shown in FIG. 4 . In this embodiment, an analog output from the error amplifier EA controls a power transistor 31 of the power stage 3 . The conduction of the power transistor 31 follows the analog output from the error amplifier EA, and the conduction decides the current to be extracted from the primary photovoltaic device group 21 .
[0041] There is power loss in a linear regulator. To avoid it for better efficiency, the linear regulator can be replaced by a switching regulator, such as, using a PWM (pulse width modulation) circuit in the analog comparison and control circuit 50 . The details of a PWM circuit and how it regulates voltage are not explained here for that they are known by one skilled in this art. It should be noted that the use of a PWM circuit is not the only approach; other modulation circuits such as PFM (pulse frequency modulation) circuit can be used in the analog comparison and control circuit 50 .
[0042] As an example, please refer to FIG. 5 , which is the third embodiment according to the present invention. In this embodiment, the analog comparison and control circuit 50 includes an error amplifier EA, which receives the voltage at the node VR as its reference voltage, and receives the voltage Vin as the feedback voltage (maybe better phrased as “feed-forward” voltage), and compares them with each other. The result of comparison is inputted to a comparator CMP, to be compared with a sawtooth wave. A logic circuit receives the output from the comparator CMP, to generate a signal to be used for controlling the power stage 3 .
[0043] It should be noted that the above-mentioned is only one possible arrangement; there are other arrangements to achieve the same or similar purpose. The key point is to control the power stage 3 to extract energy according to the comparison between the voltage at the node VR and the input voltage Vin, in which the voltage at the node VR (about equal to Vmpp) can be obtained by a simple voltage division circuit, without complicated digital calculation module.
[0044] Under the above teaching, those skilled in this art can readily think of many variations. For example, the resistors R 1 and R 2 can be replaced by other devices having suitable DC resistances. Moreover, if the number of diodes connected in series in the reference photovoltaic device group 22 is arranged to be around 70%-90% of the number of diodes connected in series in the primary photovoltaic device group 21 , the resistors R 1 and R 2 even can be omitted. All such variations should fall within the scope of the present invention.
[0045] In the embodiment of FIG. 5 , the energy generated by the reference photovoltaic device group 22 is unutilized because it is not supplied to the load 4 . If it is desired to fully utilize the energy generated by every photovoltaic device, under the spirit of the present invention, the circuit can be modified as below. FIG. 6 is a schematic circuit diagram showing a fourth embodiment according to the present invention. In this embodiment, all photovoltaic devices are productive (hence, the circuit only includes the primary photovoltaic device group 21 , without the reference photovoltaic device group 22 ). On the one hand, the primary photovoltaic device group 21 generates the input voltage Vin; on the other hand, it is electrically connected to ground via a diode DR and a capacitor CR. The voltage across the capacitor CR is the reference voltage VinREF. When the power stage 3 is not active, the right side of the input voltage node Vin is equivalent to an open circuit; the input voltage Vin is equal to the open circuit voltage Voc of the primary photovoltaic device group 21 , and the reference voltage VinREF is equal to the open circuit voltage Voc minus the voltage across the diode DR. This voltage charges the capacitor CR and becomes the voltage across the capacitor CR. Similar to the previous embodiments, by properly arranging the resistances of the resistors R 1 and R 2 , the voltage at the node VR is equal to about 80% of the open circuit voltage Voc, i.e., about Vmpp. The diode DR can be a normal diode, a Shocky diode, or other diode devices.
[0046] In the above-described circuit, when the power stage 3 is active in extracting energy, the right side of the input voltage node Vin is not an open circuit. If the circuit keeps operating in such condition, the input voltage Vin will no more be equal to the open circuit voltage Voc of the primary photovoltaic device group 21 . When the capacitor CR gradually discharges, or when the photo energy received by the primary photovoltaic device group 21 varies, the voltage at the node VR inputting to the error amplifier EA will be inaccurate, deviating from Vmpp. Therefore, although the above-described circuit is able to provide the basic function, it is preferred to periodically turn off the power stage 3 so that the right side of the input voltage node Vin is equivalent to an open circuit, and that the capacitor CR can be charged. To periodically charge the capacitor CR can be viewed as an analog calibration process to calibrate the voltage at the node VR so that it is equal to Vmpp. To this end, a circuit embodiment is shown in the figure. The logic circuit 53 has an enable input EN, which receives a signal ENPWM having a waveform as shown in the figure. Most of the time the signal ENPWM enables the logic circuit 53 (L 1 ), but it periodically disables the logic circuit 53 to turn off the power stage 3 , so that the capacitor CR can be charged. In practical application, the period L 1 can last for several to several tens of seconds, while the period L 2 is in the order of milliseconds. The foregoing approach to indirectly turn off the power stage 3 by controlling the logic circuit 53 , is only one among many possible approaches. For example, to provide a switch at the right side of the input voltage node Vin, is an alternative. The key point is to periodically turn off the power stage 3 so that the right side of the input voltage node Vin is an open circuit, and that the capacitor CR can be charged. All variations achieving such purpose should fall within the scope of the present invention.
[0047] In the embodiment shown in FIG. 6 , because the diode only provides one-way conduction, if light intensity decreases drastically, the voltage on the capacitor CR might not follow instantly, affecting the accuracy of the voltage VR. To solve this, as shown in the fifth embodiment of FIG. 7 , a switch SW operating in an opposite phase to the signal ENPWM is provided at the left side of the input voltage node Vin (the switch SW may be, e.g., a PMOSFET switch, or an NMOSFET switch operated by an inverted signal of ENPWM). When the power stage is turned off (period L 2 ), the switch SW is ON so that the primary photovoltaic device group 21 can charge the capacitor CR; when the power stage 3 is extracting energy, the switch SW is OFF so that the primary photovoltaic device group 21 only provides voltage to the input voltage node Vin, but does not charge the capacitor CR. Thus, the voltage on the capacitor CR can be kept very close to the open circuit voltage Voc of the primary photovoltaic device group 21 .
[0048] In all of the above-mentioned embodiments, to be precise, when the right side of the input voltage node Vin is open circuit, the primary photovoltaic device group 21 is not in a complete open circuit status, that is, the input voltage Vin is not precisely equal to the open circuit voltage Voc. There is a small amount of load current flowing through the path from the primary photovoltaic device group 21 -Vin-DR or SW-VinREF-R 1 -R 2 to ground. Hence, if it is desired to obtained a precise open circuit voltage Voc, and to maintain the voltage on the capacitor CR longer so that the capacitor charging frequency can be reduced, a unit gain circuit can be provided in said path to ensure open circuit status, as shown in the two embodiments of FIGS. 8 and 9 . In the sixth embodiment of FIG. 8 , because the diode DR only provides one-way conduction, a weak current source of low current amount is provided so that the capacitor CR can be discharged. In the seventh embodiment of FIG. 9 , because the switch SW provides bi-directional conduction, a current source is not required. The other parts of these two embodiments are similar to those of FIGS. 6 and 7 , and the details thereof are not redundantly repeated here.
[0049] The above-mentioned embodiments are based on an estimation of Vmpp as 70% to 90% of the open circuit voltage Voc. Under the second concept of the present invention, Vmpp can be estimated more accurately.
[0050] FIG. 10 shows the eighth embodiment according to the present invention. In this and following embodiments, the analog comparison and control circuit 50 is shown as a simple block without showing its details, for simplicity of the drawings. The reference voltage VinREF in this embodiment can be extracted from the output of the primary photovoltaic device group 21 , or the output of a reference photovoltaic device group (not shown), or a predetermined constant voltage. A fixed resistor R 3 and a variable resistor R 4 form a variable voltage divider circuit which divides the reference voltage VinREF to determine the voltage at the node VR; in other words, the resistance of the variable resistor R 4 determines the voltage at the node VR, making it equal to Vmpp. It should be noted that the variable resistor R 4 is only one among many usable devices; any other device with variable resistance, even if its resistance does not vary linearly, can be used for the purpose of the present invention, such as a MOSFET, a JFET, a pinch-resistor, etc. The key point is to adjust the voltage at the node VR by the variable voltage divider circuit; any arrangement serving this purpose meets the requirement of the present invention.
[0051] The resistance of the variable resistor R 4 is controlled by a variable resistor control circuit 7 in a manner as follows. Referring to FIG. 1 , at the left side of the MPP on the V-I curve, when voltage decreases, power increases, with opposite slope directions; at the right side of the MPP on the V-I curve, when voltage increases, power increases, with the same slope directions. Thus, by a comparison between the slope direction of the output voltage of the primary photovoltaic device group 21 and the slope direction of the output power, it can be decided as to where the present V-I relationship stands, i.e., at the left side or right side of the MPP. The resistance of the variable resistor R 4 can be adjusted accordingly to move the voltage at the node VR towards Vmpp. Under this concept, in the circuit of FIG. 10 , a direction comparison circuit 60 is provided, which receives the input voltage Vin (corresponding to the output voltage of the primary photovoltaic device group 21 ) and the power at the output terminal (corresponding to the output power of the primary photovoltaic device group 21 ), and compares their slope directions. The comparison result is sent to the variable resistor control circuit 7 for adjusting the resistance of the variable resistor R 4 .
[0052] To adjust the voltage VR by means of a variable resistor control circuit 7 controlling the resistance of a variable resistor R 4 , is only an illustrative embodiment to show the concept. The spirit is to provide a circuit for adjusting the voltage VR according to a comparison between slope directions of voltage and power. When the slope directions are opposite to each other, the circuit decreases the voltage VR; when the slope directions are the same to each other, the circuit increases the voltage VR. Any variation under this spirit falls within the scope of the present invention.
[0053] There are many ways to embody the direction comparison circuit 60 , one of which is shown in the figure as an example. A power meter 40 at the right side of the figure measures the power at the output terminal (corresponding to the output power of the primary photovoltaic device group 21 ), and sends the measured result to a differential circuit (D. Ckt.) 62 ; the output of the derivative circuit 62 represents the slope of the power at the output terminal. On the other hand, another differential circuit (D. Ckt.) 61 receives the input voltage Vin and generates an output representing the slope of the input voltage Vin (corresponding to the slope of the output voltage of the primary photovoltaic device group 21 ). A slope direction comparison circuit (Slope Direct. Comp. Ckt.) 63 receives the outputs from the circuits 61 and 62 , and compare the directions of the two slopes. The comparison result is sent to the variable resistor control circuit 7 for adjusting the resistance of the variable resistor R 4 .
[0054] The ninth embodiment shown in FIG. 11 shows an example of detailed structure of the direction comparison circuit 60 . It includes operational amplifiers OP 1 and OP 2 , and comparators CP 1 and CP 2 . The comparators CP 1 and CP 2 respectively compare the outputs of the operational amplifiers OP 1 and OP 2 with the voltage stored in the capacitors C 1 and C 2 at a previous time point, and determine the slope directions. The output of the exclusive OR gate XOR indicates whether the slope directions are the same or opposite. It should be noted here that what FIG. 11 shows is only one example among many possible arrangements, which is not intended to limit the scope of the present invention. For instance, the differential circuits 61 and 62 in FIGS. 10 and 11 can be replaced by other high pass filter circuits to obtain the same effect. This is because, under the concept of the present invention, it is not required to obtain accurate values of the slopes, but instead only the slope directions of the output voltage and the output power of the primary photovoltaic device group 21 . As another example, the function of the comparators CP 1 and CP 2 is to transfer the outputs of the operational amplifiers OP 1 and OP 2 to digital signals for inputting into the exclusive OR gate XOR. If the operational amplifiers OP 1 and OP 2 are designed so that their outputs can be distinguished and recognized by a logic operation circuit, the slope direction comparison circuit 63 does not have to include the comparators CP 1 and CP 2 ; the outputs of the operational amplifiers OP 1 and OP 2 can be compared with each other directly.
[0055] FIGS. 12 and 13 show two examples of the detailed structure of the variable resistor control circuit 7 , which are the tenth and eleventh embodiments of the present invention. Again, these two embodiments are illustrative rather than limiting. In details, in the embodiment shown in FIG. 12 , when the output of the direction comparison circuit 60 is low, the upper PMOS switch is ON, so that the capacitor C 7 is charged along a positive direction and adjust the variable resistor R 4 corresponding to the positive direction; when the output of the direction comparison circuit 60 is high, the lower NMOS switch is ON, so that the capacitor C 7 is charged along a negative direction and adjust the variable resistor R 4 corresponding to the negative direction. The foregoing “positive” and “negative” directions, the types and locations of the PMOS and NMOS transistors, and the adjusted directions of the variable resistor R 4 , can be arranged according to the design of the direction comparison circuit 60 . For example, if the exclusive OR gate XOR is replaced by an exclusive NOR gate XNOR, then opposite signals and devices should be used.
[0056] The embodiment of FIG. 13 includes a transconductor GM which generates current corresponding to the comparison between the output of the direction comparison circuit 60 and a reference voltage VB, to charge the variable resistor R 4 for controlling the variable resistor R 4 . The reference voltage VB can be set at a value between the high level and low level of the output of the direction comparison circuit 60 , so that, when the output of the direction comparison circuit 60 is low, the transconductor GM generates positive current to charge the capacitor C 7 along a positive direction and adjust the variable resistor R 4 corresponding to the positive direction; when the output of the direction comparison circuit 60 is high, the transconductor GM generates negative current to charge the capacitor C 7 along a negative direction and adjust the variable resistor R 4 corresponding to the negative direction. Similar to the previous embodiment, the “positive” and “negative” directions (the positive and negative inputs of the transconductor GM) can be arranged according to the output types of the direction comparison circuit 60 , i.e., they may be reversed if needed.
[0057] Referring to FIG. 1 again, according to the present invention, besides determining MPP based on the voltage-power relationship, it is also possible to determine MPP based on the current-power relationship. At the left side of the MPP on the V-I curve, when current increases, power increases, with the same slope directions; at the right side of the MPP on the V-I curve, when current increases, power decreases, with opposite slope directions. Thus, by a comparison between the slope direction of the output current of the primary photovoltaic device group 21 and the slope direction of the output power, it can be decided as to where the present V-I relationship stands, i.e., at the left side or right side of the MPP. FIG. 14 shows the twelfth embodiment of the present invention to embody this concept.
[0058] In the embodiment shown in FIG. 14 , a current sensing circuit 8 senses the input current Iin (the output current of the primary photovoltaic device group 21 ), which is compared with the output of the power meter 40 (the output power of the primary photovoltaic device group 21 ) in the direction comparison circuit 60 . The resistance of the variable resistor R 4 is adjusted according to the result of comparison, to move the voltage at the node VR towards Vmpp. Apparently, because the relationship between current and power slope directions is opposite to the relationship between voltage and power slope directions, the detailed structure of the direction comparison circuit 60 or the variable resistor control circuit 7 should be designed based on such fact. For example, if a circuit shown in any of FIGS. 11-13 is used, an inverter gate should be added at a proper location, or an exclusive NOR gate XNOR should be used instead of the exclusive OR gate XOR, or the locations of the PMOS and NMOS transistors in FIG. 12 should be interchanged, or the positive and negative inputs of the transconductor GM should be interchanged, etc.
[0059] The same as above, to adjust the voltage VR by means of a variable resistor control circuit 7 controlling the resistance of a variable resistor R 4 , is only an illustrative embodiment to show the concept. The spirit is to provide a circuit for adjusting the voltage VR according to a comparison between slope directions of current and power. When the slope directions are opposite to each other, the circuit decreases the voltage VR; when the slope directions are the same to each other, the circuit increases the voltage VR. Any variation under this spirit falls within the scope of the present invention.
[0060] There are many ways to embody the current sensing circuit 8 , one of which is shown in FIG. 15 . The circuit shown in FIG. 15 senses the current Iin and transfers it to a voltage signal to be sent to the direction comparison circuit 60 . Again, this embodiment is for illustration, not for limitation.
[0061] A power meter 40 is used in the embodiments of FIGS. 10 , 11 and 14 . From a first sight, the use of a power meter complicates the circuit, because a power meter needs to measure and calculate product of current and voltage values. Actually, under the concept of the present invention, it does not require an accurate measurement of power, and thus it does not require a sophisticated power meter. What is required is only to know the direction of changes of the output power of the primary photovoltaic device group 21 ; therefore, it is sufficient to use a very simple power meter (as described later with reference to FIGS. 17 and 18 ), or even without a power meter. FIG. 16 shows the thirteenth embodiment of the present invention, which is a variation based on the embodiment of FIG. 14 . As shown at the right side of the figure, since the load 4 is a battery in most cases, and the voltage of a battery changes very slowly, the power meter 40 can be replaced by a current sensing circuit 41 which only measures the current flowing to the load 4 , and transfers the sensed result to a voltage signal to be inputted to the differential circuit 62 . Thus, the same purpose as that of the circuit shown in FIG. 14 can be achieved. An example of the detailed structure of the current sensing circuit 41 is shown in FIG. 15 . Likely, the right side of FIG. 10 or FIG. 11 can be replaced by a current sensing circuit in a similar fashion.
[0062] If it is desired to take the voltage variation of the load 4 into consideration, we can use a “power trend meter” having a much simpler structure, instead of a power meter. A power trend meter compares the power at the present time point with the power at a previous time point, and generates a signal corresponding to the comparison result. It should be emphasized that the power trend meter only needs to show the direction of power changes, which does not even need to be proportional to the actual power changes. An example of such power trend meter is shown in FIG. 17 as the fourteenth embodiment of the present invention, wherein the power trend is estimated by sensing the heat of a resistor. As shown in the figure, a bipolar transistor Q BP is used to sense the heat variation on a resistor Rs. In general, the base to emitter voltage variation (dV BE ) of a bipolar transistor corresponds to temperature variation (dT) as:
[0000] dV BE /dT≈− 2 mV/° C.
[0000] Thus, the voltage variation can be used to represent the power trend. However, it should be noted that this is an inverted analog signal and should be processed accordingly.
[0063] If it is desired to detect the actual current and voltage, that is, if it is not desired to simply measure the power trend, the fifteenth embodiment of the present invention shown in FIG. 18 provides a simple solution. Please refer to FIG. 11 in conjunction with FIG. 18 , the circuit of FIG. 18 includes the power meter 40 , the differential circuit 61 , and the comparator CP 2 . The output signal PRFI indicates the power changing direction, i.e., the plus or minus sign of d(V*I)/dt, in which d(V*I) is the power change, and dt is the time change. PRFI is a digital signal which can be sent to the exclusive OR gate XOR in FIG. 11 for a logic operation with the output from the comparator CP 1 , to generate a control signal for controlling the variable resistor control circuit 7 . As shown in FIG. 18 , although the circuit detects current and voltage, no complicated multiplication is required, so the circuit is much simpler than a typical power meter.
[0064] In summary, in order to obtain precise MPP, prior art circuits requires complicated digital calculation circuits to calculate precise current and voltage values, which requires transistors in the number of several tens of thousands; however, the analog circuit according to the present invention only requires less than one thousandth of transistors in number as compared with prior art. Thus, the present invention is apparently much more advantageous than prior art.
[0065] The spirit of the present invention has been explained in the foregoing with reference to the preferred embodiments, but it should be noted that the above is only for illustrative purpose, to help those skilled in this art to understand the present invention, not for limiting the scope of the present invention. Within the same spirit, various modifications and variations can be made by those skilled in this art. For example, additional devices may be interposed between any two devices shown in the drawings, such as a delay circuit, a switch, or a resistor, without affecting the primary function of the circuit. In view of the foregoing, it is intended that the present invention cover all such modifications and variations, which should interpreted to fall within the scope of the following claims and their equivalents. | The present invention discloses an analog photovoltaic power circuit, comprising: a photovoltaic device group for receiving photo energy to generate an input voltage; a power stage circuit for converting the input voltage to an output voltage; an optimum voltage estimation circuit for receiving a predetermined voltage and estimating an optimum voltage according to a direction of variation of the input voltage and a direction of variation of the power generated by the photovoltaic device group; and an analog comparison and control circuit for comparing the optimum voltage with the input voltage, to thereby control the operation of the power stage circuit. | 8 |
This application is a divisional of co-pending application Ser. No. 09/163,720 filed Sep. 30, 1998.
BACKGROUND OF THE INVENTION
The present invention relates to the field of lined explosive charges for perforating targets. More particularly, the present invention relates to a disk shaped component in a shaped charge liner for producing a material penetrating jet to produce a large target perforation downhole in a wellbore.
The invention is particularly useful in the field of downhole well casing perforations. Well casing is typically installed in boreholes drilled into subsurface geologic formations. The well casing prevents uncontrolled migration of subsurface fluids between different well zones and provides a conduit for production tubing in the wellbore. The well casing also facilitates the running and installation of production tools in the wellborfe. Well tubing can be installed within well casing to convey fluids to the well surface.
To produce reservoir fluids such as hydrocarbons from a subsurface geologic formation, the well casing is perforated by multiple high velocity jets from perforating gun shaped charges. A firing head in the perforating gun detonates a primary explosive and ignites a booster charge connected to a primer or detonator cord. The detonator cord transmits a detonation wave to each shaped charge.
In a conventional shaped charge, booster charges within each shaped charge activate explosive material which collapse a shaped liner toward the center of a cavity formed by the shaped charge liner. The collapsing liner generates a centered high velocity jet for penetrating the well casing and the surrounding geologic formations. The jet properties depend on the charge case and liner shape, released energy, and the liner mass and composition. Shaped charge jets perforate the well casing and establish a flow path for the reservoir fluids from the subsurface geologic formation to the interior of the well casing. This flow path can also permit solid particles and chemicals to be pumped from the casing interior into the geologic formation during gravel packing operations.
Various efforts have been made to modify the performance of shaped charges. Barriers and voids have been placed within the explosive material to modify the detonation wave shape collapsing the liner. Examples of detonation wave shaping techniques are described in U.S. Pat. No. 4,594,947 to Aubry et al. (1986), U.S. Pat. No. 4,729,318 to Marsh (1988), and U.S. Pat. No. 5,322,020 to Bernard et al. (1984). In each of these patents, detonation wave shapers are positioned in the explosive material between detonator cord and the liner. In U.S. Pat. No. 5,753,850 to Chawla et al. (1998), a spoiler was positioned within the liner cavity to modify the perforating jet shape.
Other efforts have been made to modify perforating jet performance by changing the liner shape. In U.S. Pat. No. 3,268,016 to Bell (1964), a disk-like appendage in a liner was provided to peen the rough perforation burr after the leading perforating jet portion penetrated through the target. The disk-like appendage was configured to form a slug portion with a diameter larger than the perforating jet entry hole diameter. In U.S. Pat. No. 5,559,304 to Schweiger et al. (1996), a liner having a flattened outer surface for the purpose of stretching and flattening the perforating jet shape. The flattened central region of the liner apex reduced the thickness of the liner between 10-15 percent. The velocity of the perforating jet was reduced to enhance stable flight and end-ballistic performance. In U.S. Pat. No. 4,702,171 to Tal et al. (1987), the liner apex was hollowed, and in U.S. Pat. No. 3,137,233 to Lipinski (1962), a conical liner represented a squared liner apex in one view for the purpose of facilitating the liner manufacture.
One technique for generating a large diameter perforation uses a mandrel to shape the perforating jet shape. In U.S. Pat. No. 4,841,864 to Grace (1989), a mandrel was placed along the liner longitudinal axis to control the perforating jet shape. In U.S. Pat. No. 5,155,297 to Lindstadt et al. (1992), a solid weight member was centrally positioned in the liner to stabilize the deformation of the perforating jet. The weight member extended into the explosive charge and through the liner material.
Another technique for generating a larger perforating hole incorporates a liner having a hemispherical portion attached to a conical skirt. Because the hemispherical portion has a discontinuity in the liner slope, a negative velocity gradient creates a bulge in the material perforating jet which leads to a larger hole in the target material. Although a larger hole is created, the size of the hole is limited by the configuration of the composite liner surfaces.
In certain well completion activities such as gravel packing operations, large diameter well perforations are desirable to facilitate the rapid placement of solid particles into the well. To accomplish this objective, a perforating gun should remove a large target surface area from the casing before the energy of the perforating jet is expended. Conventional shaped charge techniques are limited in their ability to generate large casing holes without significantly increasing the shaped charge size. Accordingly, a need exists for an apparatus that can efficiently create large diameter perforations or minimum penetration in well casing and other selected targets.
SUMMARY OF THE INVENTION
The present invention provides an apparatus actuatable by a detonator to perforate a material. The apparatus comprises an explosive material which can be initiated by the detonator to create a detonation wave, a shaped liner proximate to said explosive material and having a first end facing the detonator and having a second end formed about a longitudinal axis through a hollow space, wherein said shaped liner is collapsible about said hollow space when impacted by said detonation wave to form a material penetrating jet, and a disk proximate to said liner first end and deformable by said detonation wave to modify the material penetrating jet by resisting axial movement of said collapsing liner toward said liner longitudinal axis.
In other embodiments of the invention, the explosive material can be positioned within a housing recess, the disk can be attached to the liner, and the disk can be formed with different materials in different configurations. The disk surfaces can be flat, concave, convex, or other shapes, and the disk can be integrated into the liner.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a liner and disk proximate to the explosive material in a charge case.
FIG. 2 illustrates a disk integrated within a shaped charge liner.
FIG. 3 illustrates a disk having a greater thickness than the liner.
FIG. 4 illustrates a disk having less thickness than the liner.
FIGS. 5-9 illustrate different configurations for disks having flat, concave, or convex surfaces.
FIG. 10 illustrates a multiple material disk having axially positioned layers.
FIG. 11 illustrates a multiple material disk having radially positioned layers.
FIG. 12 illustrates a disk having an aperture through the disk middle section.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As previously described, conventional shaped charges initiate an explosive material to collapse a liner material about a cavity defined by the liner. The collapsing liner material moves axially inwardly toward the longitudinal axis and simultaneously moves outwardly in the direction of the detonation wave to generate a high velocity, perforating jet. Energy from the detonation wave is transferred to the individual particles of the collapsing liner material. The penetration hole diameter of the conventional perforating jet depends on the target composition, the perforating jet diameter, and the energy dissipated radially as the perforating jet penetrates the target material.
The present invention significantly improves conventional large hole penetration capability by creating a substantially larger hole in a target. The invention accomplishes this function by resisting collapse of the liner toward the longitudinal axis, and by maintaining a perforating jet diameter greater than conventional jets.
Referring to FIG. 1, charge case or housing 10 defines a recessed cavity 12 having open end 14 , housing wall 16 , and closed end 18 . If the cavity 12 of housing 10 has a parabolic or elliptical shape, wall 16 and closed end 18 are collectively defined by a continuous shaped surface. Liner 20 forms a geometric figure having liner apex 22 and liner base 24 formed about longitudinal axis 26 . Liner 20 can be symmetrical about longitudinal axis 26 , or can be offset. Liner 20 is positioned within cavity 12 so that liner apex 22 faces housing closed end 18 . Liner base end 24 faces toward open end 14 . Liner 20 defines an interior volume or hollow space 28 between liner base 24 and liner apex 22 .
High explosive material 29 is positioned between housing wall 16 and liner 20 . Detonator 30 comprises a primer or detonator cord suitable for igniting high explosive material 29 to generate a detonation wave. Such detonation wave focuses liner 20 to collapse toward longitudinal axis 26 and to form a material perforating jet. As collapsing liner moves 20 towards open end 14 in the same direction as the detonation wave travel, the perforating jet also moves in such direction consistent with the laws of mass momentum and energy conservation. The perforating jet exits housing 10 at high velocity and is directed toward the selected target. Although liner 20 is preferably metallic, liner 20 can be formed with any material suitable for forming a high velocity perforating jet.
Disk 32 is shown in FIG. 1 as a thin, flat circular plate. Disk 32 is located proximate to liner 20 near liner apex 22 and has disk edge 34 and disk surfaces 36 and 38 . Disk edge 34 can be circular, oval, rectilinear, or irregular in shape. Disk 32 is positioned within aperture 40 through liner apex 22 . As shown in FIG. 1, disk surfaces 36 and 38 are substantially flat and are substantially perpendicular to longitudinal axis 26 . In other embodiments of the invention, disk edge 34 can have an oval, irregular, or other shape, and disk surfaces 36 and 38 can be concave, convex, irregular, or another shape.
The mechanism of the perforating jet resulting from disk 32 generally performs as follows. Disk 32 is accelerated by the detonation wave along longitudinal axis 26 . Because of the curvature of liner 20 , each element of liner 20 is accelerated toward longitudinal axis 26 and forward in a direction parallel to longitudinal axis 26 . By being pushed toward longitudinal axis 26 the elements of liner 20 will create a fast moving perforating jet followed by a slug component.
The resulting jet creates a larger hole in the target than conventional jets formed in the absence of a disk. Disk 32 interrupts the normal formation of the perforating jet by interrupting or resisting the inner collapse of liner 20 toward longitudinal axis 26 . This change in collapse flow significantly alters the conditions forming the perforating jet component and the slug component. The mass and velocity of the perforating jet do not change materially by altering the final position of the collapse process, but the resulting perforating jet diameter is increased because the jet flow is formed away from longitudinal axis 26 as the residue from disk 32 is accelerated along longitudinal axis 26 . The jet hole size, penetration, and other factors can be controlled by the size, mass, thickness, composition, orientation, and other characteristics of disk 32 .
FIG. 2 illustrates another embodiment of the invention wherein disk 40 is integrated into liner 42 . Liner 42 is formed with hemispherical section 44 and conical section 46 . The discontinuity in the slope between hemispherical section 44 and conical section 46 creates a bulge in the resulting perforating jet, and this bulge is enhanced by the operation of disk 40 in response to a detonation wave. By having a discontinuity in the second (or higher) derivative of the liner 42 contour, a negative velocity gradient is generated to form the perforating jet bulge. Disk 40 interferes with the perforating jet to increase the size of the hole generated by the resulting perforating jet. The bulge formation can be controlled to modify the shape and location of the bulge relative to the other portions of the perforating jet.
FIG. 3 illustrates another embodiment of the invention wherein disk 48 has a thickness t D greater than the thickness t L of liner 50 . As illustrated, surfaces 52 and 54 of disk 48 are offset from liner 50 with dimensions “a” and “b”, so that t D =t L +a+b. In different embodiments of the invention, surfaces 52 or 54 can be flush with the respective surfaces of liner 50 , or can be disposed in other positions relative to the respective surfaces along longitudinal axis 26 . The position of liner 50 along longitudinal axis 26 can be adjusted to time the movement of disk 48 relative to the collapse of liner 50 following initiation of explosive material 29 . By moving the initial position of disk 48 along longitudinal axis 26 toward the direction of the perforating jet, the impact of moving disk 48 on the perforating jet can be slowed. In another embodiment of the invention as shown in FIG. 4, the thickness of disk 56 can be less than that of liner 50 .
FIGS. 5-9 illustrate other embodiment of a disk suitable to use in cooperation with a shaped charge liner. In FIG. 5, disk 52 has concave surface 54 and flat surface 56 . In FIG. 6, disk 58 has concave surface 60 and concave surface 62 . In FIG. 7, disk 64 has concave surface 66 and convex surface 68 . In FIG. 8, disk 70 has convex surface 72 and flat surface 74 . In FIG. 9, disk 76 has convex surface 78 and convex surface 80 .
Disks such as disk 32 can be made with materials such as copper, from other metallic materials, from non-metallic materials, from solids or from pressed powders, or other components or combinations of components. The density of disk 32 can be greater or less than the liner density. The type of material forming disk 32 will affect the thickness and diameter of the optimal shape of the disk 32 and the desired location of disk 32 relative to the liner. Various combinations of materials are useful to accomplish different functions. FIG. 10 illustrates disk 82 having axially positioned layers 84 and 86 , and FIG. 11 illustrates disk 88 having radially positioned layers 90 and 92 . Other configurations and orientations of two or more materials are possible. Longitudinal axis 26 can bisect disk 32 or can be placed offset from the center of disk 32 . As shown in FIG. 12, disk 90 can have aperture 92 through the interior of disk 90 to modify the shape and location of the perforating jet bulge.
Although the invention has been described in terms of certain preferred embodiments, it will become apparent to those of ordinary skill in the art that modifications and improvements can be made to the inventive concepts herein without departing from the scope of the invention. The embodiments shown herein are merely illustrative of the inventive concepts and should not be interpreted as limiting the scope of the invention. | A shaped charge for generating a large hole in material such as well casing downhole in a wellbore. A shaped charge liner is oriented about a longitudinal axis, and a disk is positioned at the liner apex. When an explosive material is initiated the liner collapses into a perforating jet. The disk alters the jet formation process and changes the shape and location of a bulge within the perforating jet. Consequently, the shape of the perforating jet retains a larger diameter for generating a larger hole in the material to be perforated or for controlling the penetration depth. The disk surfaces can be flat, concave, convex or other shapes, and the disk composition can be varied to accomplish different design criteria. | 4 |
[0001] The present invention relates to a new method of power converter regulation, in particular regulation of very high frequency (VHF) power converters operating at frequencies in the MHz range.
BACKGROUND OF THE INVENTION
[0002] Reducing the physical size of electronic equipment in power applications is desired in order to add more features into existing products, integrate power converters in places normally unfit for such equipment, and reduce system cost. Increasing the operating frequency of the converter is a direct way of reducing the size of energy storage elements such as bulky capacitors and inductors, which usually dominate the overall converter volume. Due to reduction in energy storage requirements the transient response is dramatically increased. LED lighting applications and point-of-load (PoL) converters particularly benefit from very high frequency (VHF) converters due to size, price, and weight reduction, and faster transient response.
[0003] Conventionally, burst mode control is used to control the output voltage or current of resonant power converters. Burst mode control allows the converter designer to optimize resonant power converters for operation in one operating point. The output voltage or current is controlled by turning the resonant power converters on or off as necessary to maintain constant output voltage or current. A disadvantage of burst mode control is that the EMI performance is the same or worse compared to hard switched converters at the same modulation frequency. Typically, the modulation frequency ranges from 20 kHz to 1 Mhz.
[0004] Typically, prior art burst mode control is either hysteresis based, or pulse width modulation (PWM) based with constant switching frequency.
[0005] With hysteresis and PWM control, fast responses—ideally zero time delays—of the components of the regulation loop are required so that low cost components cannot be used.
[0006] The converter start-up circuit must also provide very little delay. As a consequence, passive start-up circuits (which have lower cost) are usually not an option.
[0007] Hysteresis based control results in tight output regulation, but requires a high cost, high performance comparator with very small propagation delays.
[0008] A conventional hysteretic burst mode control method of controlling a power converter, comprises the steps of
turning the power converter on when an absolute value of a sense voltage is less than or equal to an absolute value of a first reference voltage, and turning the power converter off when the absolute value of the sense voltage is larger than or equal to an absolute value of a second reference voltage that is larger than the absolute value of the first reference voltage.
[0011] Typically, the difference between the first and second reference voltages is a predetermined fixed value.
SUMMARY OF THE INVENTION
[0012] The present invention provides a modulation method for obtaining accurate output regulation of a power converter while exploiting inherent delays in the feedback loop.
[0013] Contrary to hysteresis on/off control, i.e. hysteretic burst mode control, the new method does not require immediate responses to comparisons of a sense voltage to two reference voltages. Rather, according to the new method, only one reference voltage is used, and delays in the feedback loop are allowed to cause some variation of an output of the power converter. The variation can be predicted and accounted for during the converter design process.
[0014] Thus, a new method of controlling a power converter is provided, comprising the steps of
turning the power converter on when an absolute value of a sense voltage is less than or equal to an absolute value of a reference voltage and a first time period has elapsed since a previous turn-off of the power converter, and turning the power converter off when the absolute value of the sense voltage is larger than or equal to the absolute value of the reference voltage and a second time period has elapsed since a previous turn-on of the power converter.
[0017] In the following, the new method is termed phase-shift burst mode control due to the phase shift caused by the first and second time periods. According to the new method, hysteresis is provided in the time domain.
[0018] A power converter operating in accordance with the new method is also provided.
[0019] Thus, a new power converter is provided, comprising a control circuit coupled to compare a sense voltage with a reference voltage, and having a control output that is coupled to control turn-on and turn-off of the power converter in such a way that
the power converter is turned-on when the absolute value of the sense voltage is less than or equal to the absolute value of the reference voltage and a first time period has elapsed since a previous turn-off of the power converter, and the power converter is turned-off when the absolute value of the sense voltage is larger than or equal to the absolute value of the reference voltage and a second time period has elapsed since a previous turn-on of the power converter.
[0022] The first time period may include a third time period of a predetermined duration that has to elapse from the point in time when the absolute value of the sense voltage drops below the absolute value of the reference voltage until the power converter is turned-on.
[0023] The second time period may include a fourth time period of a predetermined duration that has to elapse from the point in time when the absolute value of the sense voltage raises above the absolute value of the reference voltage until the power converter is turned-off.
[0024] The predetermined durations of the third and fourth time periods may be different.
[0025] Throughout the following disclosure, the process of alternatingly turning a power converter on and off, is termed “modulation” of the power converter, and the time between two consecutive turn-on events is termed a “modulation period”, and the rate of turn-on is termed the “modulation frequency”.
[0026] The sense voltage may correspond to an output voltage of the power converter; or an output current of the power converter; or another desired characteristic of the power converter.
[0027] An output current of the power converter is a current consumed by a load connected to an output of the power converter.
[0028] The control circuit may perform turn-off of the power converter by turning at least one switch of the power converter off, e.g. by short-circuiting the gate of a Field-Effect-Transistor (FET) to its source; or, the base of a bipolar transistor to its emitter, and turn-on of the power converter by allowing the at least one switch of the power converter to turn-on again, e.g. by opening the short-circuit.
[0029] The control circuit may also perform turn-on and turn-off of a resonant power converter by changing the impedance or the loop-gain of the resonant part of the power circuit, whereby the resonant power converter is turned-off by changing the impedance or loop-gain to a first value at which the resonant part of the power circuit does not oscillate, and whereby the resonant power converter is turned-on by changing the impedance or loop-gain to a second value at which the resonant part of the power circuit oscillates.
[0030] The control circuit may comprise one or more delays configured to provide at least part of one or more of the respective first and second time periods. Propagation delays in circuit components, such as propagation delays in a comparator, filtering elements, the power circuit, etc., may advantageously be incorporated into the appropriate time period.
[0031] The control circuit may comprise a comparator coupled to compare the sense voltage with the reference voltage, and an output of the comparator may constitute the control output that is coupled to control turn-on and turn-off of the power converter, and thus, the delays with which the comparator changes state of its output from high to low and vice versa, in response to changed input(s), constitute part of the respective first and second time periods.
[0032] The delays with which the comparator changes state of its output from high to low and vice versa, in response to changed input(s), may provide at least part of the third and fourth time periods.
[0033] The output voltage of the power converter may be coupled to signal conditioning circuit, such as a low-pass filter, etc., configured to output the sense voltage.
[0034] The power converter may be of any known type of power converters, and in particular any type of VHF power converters, such as square wave power converters, quasi-square wave power converters, resonant transition power converters, resonant power converters, etc.
[0035] The power converter may have a plurality of power circuits operating in series and/or in parallel and/or interleaved, e.g. with inputs in series and/or parallel and/or with outputs in series and/or parallel. All or some of the plurality of power circuits may be controlled with a single control circuit.
[0036] A resonant power converter may be of any known type of resonant power converters, such as converters comprising: a class E inverter and a class E rectifier, a class DE inverter and a class DE rectifier, a class DE inverter and a class E rectifier, etc.; or, class EF2 (or class φ) converters, resonant Single-Ended Primary-Inductor Converters (SEPIC), etc.
[0037] The power converter may be driven by an oscillator, or the converter may be self-oscillating. Further, the power converter may be interleaved.
[0038] Basing control of the output of the power converter on a single reference voltage and time periods during which the power converter does not change state from a turned-on state to a turned-off state, or vice-versa, leads to lowered performance requirements for control circuit components as compared to components of conventional control circuits, e.g. utilizing PWM-control or hysteresis control. E.g., low cost components and passive start-up circuits may be used in the new control circuit.
[0039] Furthermore, it is possible to include low-pass filtering, or other signal conditioning, of the output voltage for provision of the sense voltage, thus improving signal integrity.
[0040] Increasing at least one of the first and second time periods provided by the control circuit lowers modulation frequency of the control output signal controlling the on/off states of the power converter. This in turn increases variation of the output voltage; however, output voltage variations may be lowered by provision of a suitable output filter at the output of the power converter.
[0041] Due to the time periods provided by the control circuit, the response time of the control circuit is longer than the response time of hysteresis control. Still, desired regulation is achieved within one modulation cycle.
[0042] Conventional control circuits, such as PWM-control or hysteresis control, rely on high-end components and on minimizing time delays in the control circuit, leading to higher cost and lower component availability than for the corresponding components of the new control circuit.
[0043] For example, a comparator used in the new control circuit may be 9-10 times slower than a comparator used in a conventional control circuit, e.g. 4.5 ns vs 40 ns.
[0044] As further explained below, at least one of, or both of, the first and second time periods may be equal to, or substantially equal to, one fourth the modulation period, e.g. at 50% duty cycle, for example at least one of, or both of, the third and fourth time periods may be equal to, or substantially equal to, one fourth the modulation period, e.g. at 50% duty cycle.
[0045] The sense voltage may be a function of the output voltage supplied to a load connected to an output of the power converter; or, the sense voltage may be a function of the output current supplied to a load connected to an output of the power converter; or, the sense voltage may be a function of power, i.e. output voltage times output current, supplied to a load connected to an output of the power converter; etc.
[0046] An output capacitor connected to an output of the power converter stabilizes the output voltage supplied by the power converter. The output capacitor is charged during turn-on of the power converter and discharged during turn-off of the power converter. During turn-on, the capacitor is charged with the current supplied by the power stage of the power converter minus the current supplied to the load connected to the output of the power converter. During turn-off, the capacitor is discharged with the load current. Thus, the slope of the voltage ripple ΔV out developed across the output capacitor as a result of the charging and discharging of the output capacitor depends on the output current. If the output current is low, the slope of the voltage ripple is steep during turn-on of the power converter and low during turn-off of the power converter, and vice versa if the output current is high. This together with the first and second time periods causes the output voltage ripple to vary with varying output current and also causes the mean value of the output voltage V out to vary with varying output current. Correspondingly, the ripple of the output current I out and output power P out , and the mean value of output power P out may also vary with varying output current.
[0047] This variation may be compensated in various ways in order to lower the amount of variation and making the desired output value more constant and independent of the output current at least within a predetermined output current range.
[0048] For example, the control circuit may be configured to compensate a dependence of the sense voltage, and thereby a dependence of the output voltage; or, the output current; or the output power; etc., on the output current, for example by varying the reference voltage in dependence on the output current in such a way that the dependence of the sense voltage on the output current is compensated. For example, an increase in output voltage may be compensated by lowering the reference voltage so that the power converter is turned-on at a lower voltage thereby lowering the resulting output voltage. The change in reference voltage takes place over a plurality of modulation periods. When the load is constant, the reference voltage does not change unless an adjustment of the output, such as the output voltage or current, is performed.
[0049] Additionally; or, alternatively, the control circuit may be configured to vary at least one of the first and second time periods in dependence of the output current, whereby the dependence of the sense voltage on the output current is compensated. For example, an increase in output voltage may be compensated by lowering the second time period so that the power converter is turned-on during a shorter time period thereby lowering the resulting output voltage. When the load is constant, the first and second time periods do not change.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] Below, the new method and the new power converter are explained in more detail with reference to the drawings in which various resonant examples of the new power converter are shown. In the drawings:
[0051] FIG. 1 shows a schematic diagram of a resonant power converter with the new control circuit,
[0052] FIG. 2 shows a schematic circuit diagram of an exemplary new resonant power converter,
[0053] FIG. 3 shows a schematic circuit diagram of an exemplary new resonant power converter,
[0054] FIG. 4 shows a schematic circuit diagram of an exemplary new resonant power converter,
[0055] FIG. 5 shows a schematic circuit diagram of an exemplary new resonant power converter,
[0056] FIG. 6 shows exemplary signal conditioning circuits,
[0057] FIG. 7 shows exemplary switch drivers,
[0058] FIG. 8 shows a schematic circuit diagram of an exemplary new resonant power converter with a stop circuit,
[0059] FIG. 9 shows a switch driver with oscillator turn-off,
[0060] FIG. 10 shows a power circuit diagram of a VHF interleaved self-oscillating resonant SEPIC converter,
[0061] FIG. 11 is a plot of simulated waveforms of the power circuit shown in FIG. 10 ,
[0062] FIG. 12 shows a schematic circuit diagram of a model of a new resonant power converter used for calculation of component values,
[0063] FIG. 13 shows a circuit diagram of a control circuit used to control the power circuit shown in FIG. 10 ,
[0064] FIG. 14 is a plot of characteristic waveforms of the model shown in FIG. 12 ,
[0065] FIG. 15 is a plot of experimental waveforms of the control circuit shown in FIG. 13 ,
[0066] FIG. 16 is a plot of experimental waveforms of the power circuit shown in FIG. 10 ,
[0067] FIG. 17( a ) shows a plot of converter efficiency as a function of output power and ( b ) shows a plot of output voltage offset as a function of the load,
[0068] FIG. 18 is a flowchart of the new method,
[0069] FIG. 19 shows (a) a schematic circuit diagram of a model of the new resonant power converter together with (b) a conventional hysteretic control circuit and (c) a phase-shift burst mode control circuit,
[0070] FIG. 20 shows a plot of simulated waveforms of the model converter current and voltages controlled by the hysteretic control circuit,
[0071] FIG. 21 shows a plot of simulated waveforms of the model converter current and voltages controlled by the phase-shift burst mode control circuit, and
[0072] FIG. 22 shows schematic circuit diagrams of control circuits with varying sense voltage.
DETAILED DESCRIPTION OF EMBODIMENTS
[0073] The accompanying drawings are schematic and simplified for clarity, and they merely show details which are essential to the understanding of the new resonant power converter, while other details have been left out. The new resonant power converter according to the appended claims may be embodied in different forms not shown in the accompanying drawings and should not be construed as limited to the examples set forth herein.
[0074] Like reference numerals refer to like elements throughout. Like elements may, thus, not be described in detail with respect to the description of each figure.
[0075] FIG. 1 shows a schematic block diagram of a resonant power converter 10 controlled in accordance with the new method. The illustrated resonant power converter 10 comprises a VHF power circuit 12 , a control circuit 14 with a control output 16 , and a signal conditioning circuit 18 providing a sense voltage 20 based on and corresponding to the output voltage 22 .
[0076] The control circuit 14 is coupled to compare the sense voltage 20 with a reference voltage 24 .
[0077] Alternatively, the sense voltage 20 may be provided by a current sensor, such as a resistor, a hall element, etc., coupled so that the sense voltage corresponds to an output current of the resonant power converter 10 .
[0078] The control circuit 14 has a control output 16 that is coupled to control turn-on and turn-off of the VHF power circuit 12 of the resonant power converter.
[0079] In the illustrated examples, the output voltage and the sense voltage have positive values, so that the absolute value of the sense voltage or the output voltage is equal to the value itself.
[0080] The VHF power circuit 12 of the resonant power converter 10 is turned-on when the sense voltage 20 is less than or equal to the reference voltage 24 and a first time period has elapsed since a previous turn-off of the VHF power circuit 12 . The VHF power circuit 12 of the resonant power converter 10 is turned-off when the sense voltage 20 is larger than or equal to the reference voltage 24 and a second time period has elapsed since a previous turn-on of the VHF power circuit 12 .
[0081] The VHF power circuit 12 may be of any known resonant power converter topology with a frequency of operation in the MHz range, such as at or above 20 MHz, such as at or above 30 MHz, such as in the 30 MHz-300 MHz range, such as converters comprising: a class E inverter and a class E rectifier, a class DE inverter and a class DE rectifier, a class DE inverter and a class E rectifier, etc.; or, class EF2 (or class φ) converters, resonant SEPIC converters, etc.
[0082] The resonant power converter may be driven by an oscillator, or the converter may be self-oscillating. Further, the resonant power converter may be interleaved.
[0083] Inherent signal propagation delays of the components of the control circuit 14 forms parts of the first and second time periods, and the inherent signal propagation delays may form the entire first and second time periods. Additionally, one or more delay circuits may provide part of the first time period and/or part of the second time period, namely part of the third time period and/or part of the fourth time period.
[0084] The control circuit 14 may comprise a comparator that is coupled to compare the sense voltage 20 with the reference voltage 24 , and having a comparator output that is the control output 16 .
[0085] The delays with which the comparator changes state of its output from high to low and vice versa, in response to changed input(s), constitute part of the respective first and second time periods, namely part of the third time period and/or part of the fourth time period.
[0086] The signal conditioning circuit 18 may be a low-pass filter configured to output the sense voltage.
[0087] The control output 16 may be coupled to control turn-off of at least one power switch (not shown) of the resonant power converter 10 thereby turning the resonant power converter off.
[0088] This is illustrated in the class E inverter based resonant power converters shown in FIGS. 2 and 3 . The only difference between the resonant power converter of FIG. 2 and the resonant power converter of FIG. 3 is that inductor L 3 of FIG. 2 has been substituted by rectifier D 1 in FIG. 3 .
[0089] Alternatively, or additionally, the control output 16 may be coupled to control other parts of the resonant power converter circuit than the power switches, e.g. by enabling and disabling energy transfer from the input to the output of the resonant power converter 10 , e.g. by turning the resonant power converter on and off by changing the impedance or the loop-gain of the resonant part of the power circuit, whereby the resonant power converter is turned-off by changing the impedance to a first value at which the power circuit does not oscillate, and whereby the resonant power converter is turned-on by changing the impedance to a second value at which the power circuit oscillates.
[0090] This is illustrated in FIGS. 4 and 5 showing a class E inverter based resonant power converter similar to the class E inverter based resonant power converters shown in FIG. 3 except for the fact that the control output 16 turns S 2 on and off.
[0091] In FIG. 4 , the resonant part of the resonant power converter 10 does not oscillate when switch S 2 is turned-on, and the resonant part of the resonant power converter 10 oscillates and operates like the resonant power converter 10 of FIG. 3 when switch S 2 is turned-off.
[0092] In FIG. 5 , the functions of rectifier D 2 and switch S 2 of FIG. 4 are combined in switch S 2 functioning as a synchronous rectifier in FIG. 5 when the second self-oscillating gate driver is enabled so that the resonant power converter is turned on.
[0093] FIG. 6 shows circuit diagrams of two examples of low-pass filters that may constitute the signal conditioner 18 .
[0094] The signal conditioners shown in FIGS. 6( a ) and ( b ) may be substituted with any suitable signal conditioner chosen from other signal conditioner designs available to the person skilled in the art.
[0095] Examples of self-oscillating gate drivers are shown in FIG. 7 .
[0096] In FIG. 7( a ) , a low enable signal keeps the gate of the power switch at zero voltage, whereby oscillation of the power circuit is inhibited, while a high enable signal allows propagation of the VHF oscillator signal driving the gate of the power switch causing the power circuit to oscillate.
[0097] In FIG. 7( b ) , a low enable signal switches switch transistor S aux off and keeps the gate of the power switch at a constant voltage, whereby oscillation of the power circuit is inhibited, while a high enable signal allows propagation of the VHF oscillator signal driving the switch transistor S aux on and off thereby driving the power switch on and off causing the power circuit to oscillate.
[0098] The gate drivers shown in FIGS. 7( a ) and ( b ) may be substituted with any suitable gate driver chosen from other gate driver designs available to the person skilled in the art.
[0099] FIG. 8 shows a schematic circuit diagram of an exemplary new resonant power converter with a stop circuit,
[0100] FIG. 9 shows a switch driver with oscillator turn-off,
[0101] FIG. 10 is a circuit diagram of a power circuit 12 of an interleaved self-oscillating resonant SEPIC converter, wherein two power circuits 12 a , 12 b drive each other via capacitive coupling C X1 and C X2 between the switches S 1 and S 2 and operate in interleaved mode.
[0102] The power circuits are substantially identical, i.e.:
[0000] L I1 =L I2 =L I
[0000] C I1 =C I2 =C I
[0000] C X1 =C X2 =C X
[0000] C S1 =C S2 =C S
[0103] The values of the most important parasitic components of the semiconductor devices, namely diode junction capacitors and parasitic capacitors of the semiconductor switches, are included in determination of operating frequency of the resonant power converter. The oscillation frequency f S is determined mainly by the inductance L I and the total capacitance seen from the drain when the rectifiers are shorted, C DS,tot
[0000]
f
s
=
1
2
π
L
I
C
DS
,
tot
where
C
DS
,
tot
=
C
I
+
C
OSS
+
C
S
+
C
X
C
ISS
C
OSS
=
C
DS
+
C
DG
C
ISS
=
C
GS
+
C
DG
[0104] Oscillations start once the gate voltages of the MOSFET switches S 1 and S 2 become slightly higher than the MOSFET threshold voltage. Simulated waveforms of the resonant power circuit of FIG. 10 are shown in FIG. 11 . Ideally, respective waveforms of the two interleaved power converters are identical and shifted 180° with relation to each other.
[0105] If VHF ripple is neglected, the converter output can be modeled as a current source with the current value of I 0 . When an on/off modulation is applied on the converter, the current supplied by the converter i conv to C out and the load may be approximately modeled as a current square wave:
[0000]
i
conv
=
{
I
0
,
when
the
converter
is
ON
0
,
when
the
converter
is
OFF
[0106] Output current I out is equal to average value of i conv over one modulation cycle. The resulting current going into C out is i conv −I out , which has no DC component in steady state. If parasitics of C out are negligible, the resulting V out voltage waveform is a triangular wave. Assuming that turn-on and turn-off delays are independent of the output voltage rate of change, the output voltage ripple is
[0000]
Δ
V
out
=
I
out
C
out
t
D
,
on
+
I
0
-
I
out
C
out
t
D
,
off
[0000] where t D,on is the fourth time period and t D,off is the third time period, i.e. t D,on and t D,off are the control loop turn-on and turn-off delays, respectively, from the sense voltage crossing the reference voltage and to turn-on or turn-off, respectively, of the power converter. If the control circuit's delays are constant, the equation shows that V out is a linear function of I out , and the longer delay defines V out,max . In the special case of t D,on and t D,off being equal, V out is independent of I out . At any given load, the offset of V out : ΔV out,off , and f M are determined from the values of C out and the delays t D,on and t D,off by:
[0000]
Δ
V
out
,
off
=
Δ
V
out
2
t
D
,
on
-
t
D
,
off
t
D
,
off
+
t
D
,
om
and
f
M
=
I
0
C
out
Δ
V
out
I
out
I
0
(
1
-
I
out
I
0
)
[0107] Modulation frequency is highest at 50% duty cycle, i.e. the power converter is turned on half the time:
[0000]
f
M
,
max
=
1
2
(
t
D
,
on
+
t
D
,
off
)
[0108] I 0 is not known from values of circuit components. An approximate value of I 0 can be determined from Spice simulations. Once I 0 is obtained, the output filter and the feedback circuit need to be designed to provide a desired modulation frequency f M at a specified load.
[0109] FIG. 12 shows a block diagram of such a low frequency model of a resonant power. The VHF power circuit 12 is modelled as an on-off controllable DC current source.
[0110] The conditioning circuit 18 at the input of the control circuit 14 , see FIG. 13 , has a simple transfer function:
[0000]
H
(
s
)
=
A
FB
1
+
s
τ
FB
Where
A
FB
=
R
FB
2
R
FB
1
+
R
FB
2
τ
FB
=
R
FB
1
R
FB
2
R
FB
1
+
R
FB
2
C
FB
[0111] The comparator 26 of the control circuit 14 model is ideal; the propagation delay of the real comparator is added into the delay block. The delay block is represented by two different time delays, since the shutdown of the power circuit is significantly faster than the start-up sequence. This is because shutdown is performed by the auxiliary switches S aux1 and S aux2 , while during start-up C ISS is passively charged from the bias voltage V B through the biasing resistors.
[0112] FIG. 13 shows the control circuit 14 . The sense voltage 20 is low-pass filtered in H(s), a voltage divider/low pass filter 18 formed by R FB1 , R FB2 , and C FB , and input to the comparator 26 . The comparator output 16 turns the switches S aux1 and S aux2 on and off in response to the voltage difference at the comparator inputs. When S aux1 and S aux2 are on, v GS1 and v GS2 are zero and the power circuit oscillations are inhibited. Once S aux1 and S aux2 are off, c ISS1 and C ISS2 are charged through R B1 and R B2 , whereby v GS1 and v GS2 start to increase from 0 to V B . After the first time period, when v GS1 and V GS2 exceed the power MOSFET threshold voltage V th , switches S 1 and S 2 enter saturation and initiate oscillations in the power circuit. H(s) has two primary purposes: to filter high frequency noise and adjust the feedback voltage level. It also contributes to propagation delay in the feedback loop.
[0113] In FIG. 14 , characteristic voltage and current levels from a numerical example of the model are shown, where
C out =3.3 μF I 0 =1.04 A, I out =0.52 A R FB2 =2 kΩ, R FB1 =8.2 kΩ C FB =22 pF t d,on =700 ns+170 ns=870 ns t d,off =170 ns
[0120] The parameters are chosen to approximate the experimental setup described below. v gate (t) represents the gate voltages of S 1 and S 2 with removed VHF component. V out (t) passes through the single pole transfer function H(s) and results in a distorted triangular waveform v FB (t). Average value of v FB (t) is slightly lower than the reference V ref voltage, which is due to t d,on >t d,off . This is also the cause of the duty cycle of the comparator output v cmp (t) to be lower than 50%. Since the referent output voltage is 10 V, a small offset can be observed in V out (t). This offset is dependent on the duty cycle of the power circuit, the time difference t d,on −t d,off , and C out . t d,on depends on the voltage difference between V B and V th . Obtained modulation frequency is very close to 300 kHz.
[0121] In order to verify the analysis explained above, a 10.5 W prototype converter with regulation of the output voltage was produced and the measurements for the prototype converter is disclosed below.
[0122] Plots of drain, gate, and rectifier voltages in the power circuit are shown in FIG. 15 . The drain and rectifier voltages were measured with capacitance of 2.2 pF in series with an oscilloscope probe, in order to reduce influence of the probe to the power circuit. This introduces attenuation of A=0.19 in the measurement and removes the DC component of the measured voltages. Component values of the power circuit are listed in Table I. Switching frequency of the power circuit is f S =49 MHz. Open loop output voltage and output voltage and current are V out =10.2 V and I 0 =1.04 A, respectively.
[0123] When the duty cycle of 50% is obtained, I out =0.5 I 0 =0.52 A. Plots of the waveforms of the relevant voltages in the converter for this case are shown in FIG. 9 . Modulation frequency f M is at its maximum value of 300 KHz at 50% duty cycle, and drops as the duty cycle moves away from 50%. In addition, under these conditions output voltage ripple Δ V out , pp is at its maximum as well.
[0124] The comparator used in the circuit is AD8468 from Analog Devices. The component datasheet specifies 40 ns propagation delay. For comparison, a high speed TLV3501 comparator has a 4.5 ns propagation delay, which is a reduction by a factor of 9. This is by no means a limit since there are other significant contributors as well (conditioning and power circuit on-off circuit). This delay may be increased even further at a cost of a lower modulation frequency f M and higher output voltage ripple for a given C out .
[0125] FIGS. 15 and 16 illustrate relationships between the signals in time domain, V cmp+ , v cmp− , v GS , v DS , and v out (upper waveforms) with respect to the comparator output (lower waveforms). High output voltage ripple is caused by a small output filtering capacitance (C out =3.3 pF).
[0126] Efficiency of the converter is shown in FIG. 17( a ) as a function of output power. Since f M is allowed to drop significantly under light load conditions, efficiency is maintained high over wide load range (η>75% above 20% load) with peak efficiency above 81%.
[0127] Since the control is based on phase shift, a small DC error is introduced in the value of v out , which varies with the load. If the output voltage ripple is assumed triangular (which is reasonable since i conv is a current square wave), the peak values of v out are determined as:
[0000]
V
out
+
=
V
out
,
ref
+
I
0
-
I
out
C
out
Δ
t
+
V
out
-
=
V
out
,
ref
+
-
I
out
C
out
Δ
t
-
[0128] So that the offset of V out is determined by
[0000]
V
out
,
offset
=
V
out
,
ref
-
Δ
V
out
+
+
Δ
V
out
-
C
out
Δ
t
-
[0129] V out,ref is a target value for the output voltage set by V ref and R FB1 −R FB2 voltage divider. Δt + and Δt − are the time delays from a point when v out crosses v out,ref to a point where v out reaches its maximum and minimum value, respectively. Depending on the variables in these equations, v out,offset may be either positive or negative, and decreases with I out . Measured dependence of Δv out is shown in the lower plot of FIG. 17 . Both the offset and the output ripple are reduced with increase in C out , while the switching frequency will be reduced.
[0130] A comparison between the model disclosed above and experimental results show close, but not perfect matching. The reasons for this are subjects of further investigation; it is assumed that imperfections in the active components and tolerances of the passive components are the main contributors. Still, the model gives significant insight into the system operation, and can be used as a good estimate during the converter design.
[0131] Compared to hysteresis based burst mode control, the new method of controlling the resonant power converter allows use of a significantly slower and less expensive components in the control circuit, which is of importance for cost sensitive applications such as LED lighting and PoL converters. The illustrated power circuits and control circuits were implemented using only low cost commercially available components, with peak efficiency above 81% and high efficiency over wide load range.
[0132] FIG. 18 is a flowchart 100 of the new method of controlling a resonant power converter. The method starts with method step 110 wherein the resonant power converter is turned on.
[0133] When the resonant power converter is turned on, the output voltage and/or output current increases. A sense voltage is provided in the resonant power converter that corresponds to the output voltage or output current, and a reference voltage is provided in the resonant power converter that corresponds to a desired resulting output voltage or output current of the resonant power converter.
[0134] According to method step 120 , the output voltage and/or output current continue to increase until the corresponding sense voltage V sense is equal to or larger than the reference voltage V ref , and
[0135] according to method step 130 , the output voltage and/or output current continue to increase until also a second time period t 2 has elapsed since a previous turn-on of the resonant power converter.
[0136] Thus, when the sense voltage V sense is equal to or larger than the reference voltage V ref , and a second time period t 2 has elapsed since a previous turn-on of the resonant power converter, the resonant power converter is turned-off in method step 140 .
[0137] When the resonant power converter is turned on, the output voltage and/or output current decreases.
[0138] According to method step 150 , the output voltage and/or output current continue to decrease until the corresponding sense voltage V sense is equal to or less than the reference voltage V ref , and
[0139] according to method step 160 , the output voltage and/or output current continue to decrease until also a first time period t 1 has elapsed since a previous turn-off of the resonant power converter.
[0140] Thus, when the sense voltage V sense is equal to or less than the reference voltage V ref , and a first time period t 1 has elapsed since a previous turn-off of the resonant power converter, the resonant power converter is turned-off in method step 110 .
[0141] In the following, properties of the phase-shift burst mode control method for very high frequency (VHF) DC-DC converters are compared with a conventional control method with hysteresis based on comparison of a sense voltage with two threshold values. Again, an on-off controllable current source is used to model the low-frequency behaviour of VHF converters. Large output capacitance is used for output voltage filtering. The model is shown in FIG. 19( a ) .
[0142] FIG. 19( b ) shows the model of FIG. 19( a ) controlled with a conventional hysteretic control circuit and FIG. 19( c ) shows the model of FIG. 19( a ) controlled with a phase-shift burst mode control circuit.
[0143] For both circuits, the VHF power converter is operating (turned-on) when V ctrl is high, e.g. 2 Volt, delivering an average current of I 0 =2 A. The VHF power converter is turned-off when V ctrl is low, e.g. 0 Volt. In the present example, capacitor C out and load R load are set to 10 μF and 10Ω, respectively. Reference voltage V ref equals 1 V, high impedance signal conditioning network H(s) has ratio of V sense /V out =1:N, e.g. 1:10, independent of frequency. The circuit configurations and component values are selected so that the target output V out is equal to 10 V and at nominal load, the VHF power converter operates at a 50% duty cycle. It is assumed that gate drivers do not introduce any delay in any of the circuits of FIGS. 19( a )-( c ) so that V ctrl =V cmp .
[0144] In the control circuit with hysteresis shown in FIG. 19( b ) , instantaneous response of the comparator is assumed so that the comparator does not add a delay in the control loop. In the present example, the hysteresis window is V H =20 mV. The comparator turns the converter on when V sense <V ref and turns it off otherwise. Simulated waveforms of the converter voltages of the converter with hysteresis control are shown in FIG. 20 .
[0145] Modulation frequency f M , i.e. the frequency at which the converter turns on and off, is given by:
[0000]
f
M
=
I
0
/
2
2
Δ
V
out
C
out
=
I
0
/
2
2
NV
H
C
out
[0146] This equation is derived under the assumption that propagation delay t D of the comparator, the gate driver, and the power stage of the converter is zero, and the equation is a good approximation when t D 1/f M . Expensive components, e.g. comparators, gate drivers, etc., have to be used in VHF designs to realize small propagation delays in the feedback loop.
[0147] Time difference ΔT from V sense =V ref until V sense =V ref +V H in FIG. 20 equals 1/(4 f M ). If V H ->0 and t D ->1/(4 f M ), the waveforms shown in FIG. 20 turn into the waveforms shown in FIG. 21 showing simulated waveforms of the converter voltages of the converter with phase shift burst mode control. The waveforms in FIGS. 20 and 21 are aligned so that V sense voltages cross the respective V ref voltages at the same time, e.g. 2 μs, 4 μs, 6 μs, etc. The output voltage ripples are identical in FIGS. 20 and 21 , however the signal propagation delay through the feedback loop is 1/(4 f M ), see the time difference between converter currents I conv,H/PS , comparator output voltages V cmp,H/PS , etc.
[0148] With the component values mentioned above, the modulation frequency is 250 kHz.
[0149] In FIG. 21 , the power converter is turned-on at 3 μs, 7 μs, 11 μs, and 15 μs, and the power converter is turned-off at 1 μs, 5 μs, 9 μs, and 13 μs, and the first time period is equal to the second time period that is equal to 2 μs and the fourth time period, i.e. the turn-on delay t D,on , is equal to the third time period, i.e. the turn-off delay t D,off , that is equal to 1 μs.
[0150] The converter with phase shift burst mode control provides the same output voltage ripple (i.e. ΔV out,H =ΔV out,PS ) as the converter with conventional hysteresis control, while using one or more components in the feedback loop with significantly larger respective delays. The resulting delay may be distributed arbitrarily between the power stage, the comparator, and the gate driver(s). This is very important for VHF converters, since numerous start-up and shutdown techniques (self-oscillating gate drivers and converters) with small, but finite delays may be utilized in a VHF converter with phase shift burst mode control.
[0151] Turn-on and turn-off delay (t D,on and t D,off ) do not need to be equal, either. Any one of the components in the feedback loop in any combination may contribute to the values of the turn-on and turn-off delays, with the restraint that:
[0000]
t
D
,
on
+
t
D
,
off
=
1
2
f
M
[0152] Output voltage of a converter with hysteresis control resides within the range from H(s) −1 (V ref,H −V H ) to H(s) −1 (V ref,H +V H ), resulting in a voltage ripple of ΔV out,H .
[0153] This is different of a converter with phase shift burst mode control as illustrate in FIG. 19( c ) in which the output voltage V 0 is load dependent. The output voltage V 0 decreases with increased load. If output voltage ripple at I out =1A is ΔV out,PS and under assumptions of constant delay in the comparator (and otherwise ideal components), average value of V out,PS ranges from ΔV out,PS /2 at I out =0 to −ΔV out,PS at I out =I 0 linearly with I out .
[0154] The variation of the output voltage V o as a function of output current may be decreased in various ways. One way is to allow the reference voltage to change as a function of the output voltage V o to compensate for the change in the output voltage V o .
[0155] FIG. 22( a ) shows a control circuit in which the sense voltage 20 is compared to a reference voltage 28 that is adjusted as a function of the mean output voltage V o . H 1 (s) is an ordinary low-pass filter. In the illustrated circuit V ref1 =V ref −(V ref,mean −V ref ), where V ref,mean is the output of the low-pass filter H 1 (s). Thus, V ref1 =V ref when V ref,mean =V ref and V ref1 decreases when the mean output voltage V o increases and vice versa whereby the variation of the mean output voltage V o as a function of output current is counteracted.
[0156] FIG. 22( b ) shows another control circuit in which the sense voltage 20 is compared to a reference voltage 28 that is adjusted as a function of the mean of the comparator output voltage V cmp,PS 16 . The operation of the illustrated control circuit is based on the fact that the average value of V cmp,PS varies linearly with the output current I out .
[0157] Reference voltage V ref1 is formed by superposition of V ref,PS and low-pass filtered V cmp,PS . The resistor and capacitor values in the compensation network need to be chosen to provide sufficient attenuation of the ac component of V cmp,PS .
[0158] In the illustrated control circuit, when the converter operates at 50% modulation, the average of V cmp,PS equals V ref . If the output current I out is reduced, the average value of V cmp,PS is reduced, thus decreasing reference voltage V ref1 28 thereby counteracting the increase of the output voltage V o that would otherwise result for the reduced output current I out . If the output current I out is increased, the average value of V cmp,PS is increased, thus increasing reference voltage V ref1 28 thereby counteracting the decrease of the output voltage V o that would otherwise result from the increased output current I out . V ref1 is calculated with the following formulae:
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. | The present invention relates to a new method of power converter regulation, in particular regulation of very high frequency (VHF) power converters operating at frequencies in the MHz range, wherein accurate output regulation utilises inherent delays in the regulation loop, whereby, contrary to hysteresis on/off control, the new method does not require immediate responses to comparisons of a sense voltage to two reference voltages; rather, according to the new method, only one reference voltage is used, and delays in the feedback loop are allowed to cause some variation of an output of the power converter. | 7 |
BACKGROUND OF THE INVENTION
[0001] This disclosure relates to physiological sensors that are, during a measurement process, in contact with human skin and tend to exert pressure on the skin. This disclosure also relates to physiological measurement devices that utilize such sensors or probes. Below, “sensor” is used to refer to such sensors and probes. A typical example of device/sensor combination is a pulse oximeter provided with a finger sensor.
[0002] Plethysmography refers to measurement of changes in the sizes and volumes of organs and extremities by measuring changes in blood volume. Photoplethysmography relates to the use of optical signals transmitted through or reflected by blood for monitoring a physiological parameter/variable of a subject. Conventional pulse oximeters use red and infrared photoplethysmographic (PPG) waveforms, i.e. waveforms measured respectively at red and infrared wavelengths, to determine oxygen saturation of pulsatile arterial blood of a subject. The two wavelengths used in a conventional pulse oximeter are typically around 660 nm (red wavelength) and 940 nm (infrared wavelength).
[0003] Pulse oximetry is at present the standard of care for continuous monitoring of arterial oxygen saturation (SpO 2 ). Pulse oximeters provide instantaneous in-vivo measurements of arterial oxygenation, and thereby an early warning of arterial hypoxemia, for example. Pulse oximeters also display the photoplethysmographic waveform, which can be related to tissue blood volume and blood flow, i.e. the blood circulation, at the site of the measurement, typically in finger or ear.
[0004] Traditionally, pulse oximeters use the above-mentioned two wavelengths, red and infrared, to determine oxygen saturation. Other parameters that may be determined in a two-wavelength pulse oximeter include pulse rate and peripheral perfusion index (PI), for example. Increasing the number of wavelengths to at least four allows the measurement of total hemoglobin (THb, grams per liter) and different hemoglobin types, such as oxyhemoglobin (HbO 2 ), deoxyhemoglobin (RHb), carboxyhemoglobin (HbCO), and methemoglobin (MetHb). In practice, a pulse oximeter designed to measure all hemoglobin species may be provided with 4 to 8 wavelengths (i.e. light sources) ranging from around 600 nm up to around 1000 nm.
[0005] One drawback related to pulse oximeter measurements is that the use of the sensor may cause skin and tissue damages at the measurement site, typically foot or hand/finger, especially during lengthy measurement sessions. These injuries are manifested in the form of blisters or burns on skin surface. Finger injury, for example, may be caused by one or more mechanisms, which may involve electrical, mechanical and/or chemical interaction with patient's skin tissue. A major reason for this type of skin injury is the mechanical pressure that the sensor exerts on the finger. However, the injury may also result from a low leakage current caused by a damaged sensor and/or from a topical reaction to the sensor material or to the residual manufacturing chemicals. A further reason that may cause an injury is the over-heating of the light emitting diodes of the sensor. Patient's age and state typically plays a significant role in the emergence of the injuries. For example, decreased blood flow may make the tissue more vulnerable to damages. Lowered blood flow may be caused by many reasons, such as age and medication, and prolonged pressure exerted by the sensor may also deteriorate peripheral blood circulation. The time needed for an injury to develop varies a lot depending on the sensor, sensor placement and/or patient's personal attributes. However, lengthy measurement sessions involve an increased risk of skin injury. When the patient is awake and well-oriented, (s)he is usually able to tell the nurse that the sensor is pinching or otherwise painful. However, a non-conscious patient has not the possibility to speak up when the sensor starts to hurt.
[0006] Even though the sensors are carefully designed in every aspect (mechanical, electrical, etc.) to eliminate the emergence of skin injuries at the measurement site, skin injuries still occur. Therefore, manufacturers of pulse oximeter sensors typically recommend that the placement of the sensor should be changed every 3 to 4 hours and that the sensor should not be placed too tightly. However, in practice the sensor placement is usually not reported during healthcare personnel shift reports (neonatal units may be exceptions). Furthermore, in intensive care units (ICUs) the healthcare personnel have so many parameters to follow up that the SpO 2 measurement site is usually changed only when the signal has deteriorated so much that there is an alarm about low saturation, poor signal, or noise. The patient might at that point already have a pressure burn at the measurement site.
[0007] Mechanisms have been developed which generate a user notification indicating that the measurement site of the pulse oximeter sensor should be changed. These mechanisms are based on evaluation of the plethysmographic data to determine if one or more characteristics of the signal data exhibit a trend indicating deteriorating signal quality due to measurement site degradation. However, these mechanisms evaluate the need to change the measurement site only in terms of the actual measurement, to keep the quality of the measurement high enough over an extended period of time. In terms of the skin injuries, a drawback related to these mechanisms is that the signal may remain normal even though skin/tissue damages start to develop. That is, an analysis of the quality or characteristics of the signal data does not necessarily reveal alterations in patient's skin, and therefore cannot efficiently prevent skin injuries from occurring.
BRIEF DESCRIPTION OF THE INVENTION
[0008] The above-mentioned problems are addressed herein which will be comprehended from the following specification.
[0009] Occurrences of one or more predetermined events are monitored and upon detection of a predetermined start event at least one timer is started, which is provided with timer settings that depend on the detected event. Timer settings, which define the operation of the timer, may include one or more parameters that determine the length of the timer period and possible also rules that indicate when the timer is allowed to advance and when the advancing is restricted. For example, one event may trigger a timer that advances constantly (no advancing restrictions) and another event may trigger a timer that is allowed to advance only during intervals that fulfill a given criterion. As the expiration of a timer triggers a site change notification, the above use of one or more timers ensures that there will always be no more than a certain maximum time interval to the site change notification. Further, the length of the time interval may be dimensioned and controlled according to the risk of skin injury of the particular patient. For example, the length of the time interval may be shortened automatically if an event is detected that indicates increased risk of skin injury.
[0010] In an embodiment, a method for controlling sensor placement time in a physiological measurement apparatus comprises monitoring for occurrence of at least one predetermined event, wherein the at least one predetermined event comprises at least one predetermined start event and starting, upon detection of any of the at least one predetermined start event, a respective timer, thereby to start at least one timer, wherein each timer is provided with dedicated timer settings. The method further comprises generating, upon expiration of any of the at least one timer, a notification indicative of a need to change sensor placement.
[0011] In another embodiment, a physiological monitoring apparatus comprises a sensor attachable to a subject so that the sensor comes into contact with the subject's skin and an event detection unit configured to monitor for occurrence of at least one predetermined event, wherein the at least one predetermined event comprises at least one predetermined start event. The apparatus further comprises a timer control unit configured to start a respective timer in response to detection of any of the at least one a predetermined start event, thereby to start at least one timer, wherein each timer is provided with dedicated timer settings, and an indication unit configured to generate, in response to expiration of any of the at least one timer, a notification indicative of a need to change sensor placement.
[0012] In yet another embodiment, a sensor for a physiological monitoring apparatus comprises an event detection unit configured to monitor for occurrence of at least one predetermined event, wherein the at least one predetermined event comprises at least one predetermined start event and a timer control unit configured to start a respective timer in response to detection of any of the at least one a predetermined start event, thereby to start at least one timer, wherein each timer is provided with dedicated timer settings. The sensor further comprises an indication unit configured to generate, in response to expiration of any of the at least one timer, a notification indicative of a need to change sensor placement.
[0013] In a still further embodiment, a computer program product for a physiological monitoring device comprises a first program product portion configured to monitor for occurrence of at least one predetermined event, wherein the at least one predetermined event comprises at least one predetermined start event and a second program product portion configured to start a timer in response to detection of any of the at least one a predetermined start event, thereby to start at least one timer, wherein each timer is provided with dedicated timer settings. The computer program product further comprises a third program product portion configured to generate, in response to expiration of any of the at least one timer, a notification indicative of a need to change sensor placement.
[0014] Various other features, objects, and advantages of the invention will be made apparent to those skilled in the art from the following detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a block diagram illustrating one embodiment of a sensor and monitor system provided with sensor placement timing;
[0016] FIG. 2 is a flow diagram illustrating an example of the operation of the control and processing unit in terms of sensor placement timing;
[0017] FIG. 3 illustrates another embodiment of a sensor and monitor system provided with sensor placement timing;
[0018] FIG. 4 illustrates another example of the control and processing unit in terms of sensor placement timing;
[0019] FIG. 5 illustrates a further example of the operation of the control and processing unit in terms of sensor placement timing;
[0020] FIG. 6 illustrates a further embodiment of a sensor and monitor system provided with sensor placement timing; and
[0021] FIG. 7 illustrates an example of the operational entities of the control and processing unit of a monitor unit.
DETAILED DESCRIPTION OF THE INVENTION
[0022] FIG. 1 illustrates one embodiment of a sensor and monitor system provided with site timing functionality. The sensor system of FIG. 1 comprises a monitor unit 100 and a sensor unit 120 attachable to a subject (not shown). The sensor unit 120 is normally connected through a cable 130 and a monitor interface 110 to the monitor unit, but the connection between the sensor unit and the monitor unit may also be wireless. It is to be noted that the system is here discussed with respect to one monitor unit 100 and one sensor unit 120 connected to the monitor unit. However, the entire system typically includes several sensor units 120 and one or more monitor units 100 .
[0023] The monitor unit 100 may be conceived to comprise three basic elements: a computerized control and processing unit 101 , a memory 102 for the control and processing unit, and a user interface 103 , which typically comprises a display 104 and one or more user input devices 105 .
[0024] A reception branch 106 of the monitor unit is adapted to receive the electrophysiological signals from the sensor. The reception branch typically comprises an input amplifier, a band-pass filter, and an A/D converter (not shown). The digitized signal output from the A/D converter is supplied to the control and processing unit 101 , which processes the signal data and displays the analysis results on the screen of the display. The memory of the control and processing unit holds the measurement algorithm(s) 107 needed to process the data received from the sensor unit.
[0025] The sensor unit of FIG. 1 comprises a sensor element unit 121 . In case of a pulse oximeter, the sensor element unit includes at least one light source for sending optical signals through the tissue and at least one photo detector for receiving the signal transmitted through or reflected from the tissue.
[0026] For limiting the amount of time the sensor is kept at a particular measurement site, the monitor unit may further be provided with a site timing algorithm 109 configured to inform the user when the sensor should be moved to another measurement site. Even though the site timing functionality is typically in the monitor unit, it may also reside in the sensor unit. This is illustrated with a dashed box denoted with reference numeral 122 . The site timing functionality may also be distributed between the two units. It is assumed next that the functionality is implemented by algorithm 109 which is executable by the control and processing unit 101 .
[0027] FIG. 2 illustrates an embodiment of the operation of the site timing algorithm. The algorithm is configured to detect predetermined events that may include start events and control events. A start event starts a timer, whereas a control event is used to control the operation/settings of a timer. The cessation of a “sensor off” message is a typical example of a start event, whereas a user action intended to adjust the settings of a timer, such as the period of the timer, is a typical control event. The “sensor off” message is commonly used in pulse oximeters and it may be generated based on comparison of the red and infrared signals. In connection with the start of a measurement session, the cessation of the message thus indicates that the sensor is now attached to the subject and data is received in a normal manner. As discussed below, the appearance of the “sensor off” message may be regarded as a control event if the message is received in the middle of a measurement session. In this case the message indicates that the sensor may not anymore be properly fitted and should therefore be checked.
[0028] The settings of each timer (not shown in FIG. 1 ) may be stored in the memory prior to the actual measurements. In response to the detection of a predetermined event at step 201 , the site timing algorithm examines whether the event is a start event or a control event. In case of a start event, the site timing algorithm retrieves the timer settings associated with the detected start event and starts time measurement (steps 202 /yes and 203 ) to measure the time elapsed from the start event. The process then constantly monitors for the expiration of the timer (step 204 ). If the predetermined event detected is not a start event but a control event (step 202 /no), the process further checks if the event is a sensor alarm event or a regular control event (step 206 ). In case of a regular control event, the site timing algorithm retrieves the timer settings associated with the detected control event and updates the settings (step 207 ). If the respective timer is currently running, the update immediately effects the operation of the timer. If the timer is not running, the changes take effect next time the timer is started.
[0029] Further, the process constantly monitors if a new predetermined event is detected and starts or controls a timer depending on whether a start or control event is detected. When any of the started timers expires, the site timing algorithm informs the user that the measurement site of the sensor needs to be changed, cf. steps 204 and 205 . The content of the user notification displayed in step 205 may depend on the timer expired, i.e. the process may also indicate the reason for the sensor placement change.
[0030] If it is detected in step 206 that the control event is a sensor alarm event, such as reception of the “sensor off” message, the process enters a sensor alarm handling mode (step 209 ) in which the user may be informed of the need to check the sensor and/or the fitting thereof. However, sensor alarm events are in this embodiment handled during the measurement only and therefore the process first checks at step 208 , whether the measurement has already started, i.e. whether a timer is already running. If this is the case, the process monitors at step 210 for the cessation of the sensor alarm, which occurs when the user has corrected the fitting of the sensor. In response to the cessation of the sensor alarm, the process leaves the sensor alarm handling mode (step 211 ) and jumps to step 204 to continue the measurement.
[0031] In one embodiment, the predetermined events may comprise one start event only. In this embodiment, steps 201 and 202 may be combined and steps 206 to 210 omitted. Further, the arrow from step 204 /no goes to the input of step 204 . In this embodiment, the site timing algorithm thus starts, upon detection of a predetermined start event, a timer with a predetermined time interval, such as 4 hours, and displays a user notification when a predetermined time interval expires. This embodiment may further include a feature that allows the user to control the settings/operation of the timer at any stage of a measurement session. Further, the detection of sensor alarms that require a user action may affect the operation of the timer(s), and therefore a “run-time” sensor alarm handling mode is presented in FIG. 2 . However, in some embodiments, the detection of sensor alarms, such as “sensor off” messages, may have no effect on the operation of a running timer. That is, a running timer may continue running regardless of a “sensor off” message.
[0032] FIG. 3 illustrates another embodiment of the sensor and monitor system. This embodiment corresponds otherwise to the embodiment of FIG. 1 , but is augmented with a verification mechanism configured to verify the authenticity of a sensor unit connected to the monitor unit. In FIG. 3 , like reference numbers are used to denote similar elements as in FIG. 1 and below only the additional elements are described. Furthermore, the reference number of the site timing algorithm is now 309 , since the operation of algorithm deviates from that of algorithm 109 . In this example, the sensor unit also comprises a sensor memory 301 . The sensor memory may be a generic memory from which the monitor unit may read data and into which the monitor unit may write data through a memory access interface 302 . The sensor memory may thus be a plain (non-volatile) memory with no customized areas/parts, associated intelligence, or data processing capability. The memory may be, for example, an EPROM, EEPROM, or a flash memory. The memory holds a sensor-specific identifier 303 that unambiguously identifies the sensor and a sensor-specific usage identifier 304 that is indicative of the cumulative usage of the sensor. The sensor-specific identifier may be, for example, the serial number of the sensor. The usage identifier may be, for example, a usage count that indicates the total number of times the sensor unit has been used. The unique sensor-specific identifier may be stored at the manufacture stage of the memory or the sensor, and the usage identifier may be set to an initial value of zero at the manufacture stage of the sensor.
[0033] The memory 102 of the control and processing unit further holds a sensor verification algorithm 305 that is executed by the control and processing unit when a sensor is connected to the monitor unit 100 . The operation of the verification algorithm is discussed below as if no encryption or any other data security mechanisms were involved. However, it is to be noted that the sensor memory data may be in encrypted form and various known data security mechanisms may be used to encrypt/decrypt the sensor memory data and/or to verify the authenticity of the sensor and/or the integrity of the sensor memory data. The sensor verification algorithm 305 may therefore include various data security mechanisms, in addition to the basic verification mechanism applied to plain data, i.e. non-encrypted data.
[0034] The monitor unit 100 is further provided with a host memory 306 which is here presented as a separate memory unit but which may also be a memory area of the monitor memory 102 . The host memory contains the sensor-specific identifiers and sensor-specific usage identifiers for all sensors that have been used together with the monitor unit, i.e. that have been authenticated successfully by the monitor unit. This information may be in the form of a look-up table 307 , for example. However, the look-up table or the host memory may also include further sensor-specific information needed by the sensor verification algorithm, such as the security parameters related to the possible data security mechanisms involved. For each authorized sensor the system thus includes two usage identifiers, one in the sensor and the other outside the sensor in a memory accessible by the monitor unit(s). As discussed below, inconsistency between the two usage identifiers is indicative of an unauthorized sensor. The system may also create the usage identifier pair in connection with the first use of a sensor, if both the sensor memory data and the host memory data indicate that the sensor has not been used before. The two usage identifiers of an authorized sensor may be unequal even though they are consistent with each other. That is, unequal usage identifiers are not necessarily inconsistent, although equal usage identifiers of a sensor are always consistent. Rather, inconsistency is in this embodiment detected if the usage count in the sensor unit is smaller than the usage count in the monitor unit, since it indicates that the sensor is likely an illegal copy.
[0035] FIG. 4 illustrates an example of the operation of the control and processing unit 102 of FIG. 3 in terms of sensor placement timing. The control and processing unit monitors if a new sensor is connected to the monitoring unit (step 410 ). When a new sensor is detected, the control and processing unit starts an authentication process of the sensor at step 411 . If the two usage identifiers are found to be consistent for the sensor identifier in question (step 412 ), the measurement is allowed and a timer bar is displayed on the screen of the display unit 104 (step 414 ). The timer bar may be green, for example, and the height of the bar may correspond to a preset change interval of the measurement site, such as 4 hours. The process then monitors when the actual measurement is started (step 415 ). Upon detection of the start of the measurement, a timer is started that also starts to update the timer bar shown on the screen (steps 416 and 417 ). The timer bar may continuously indicate the time passed and/or the time left before change of measurement site will be due.
[0036] When it is detected in step 419 that the preset time interval has elapsed, the user is informed of the need to change the sensor to another measurement location (step 420 ). If a sensor alarm event, such as a “sensor off” message, is detected (step 418 /yes) before the timer expires, the timer may be stopped (step 421 ). A user notification may then be displayed to request the user to check the fitting of the sensor (step 422 ). When the user has corrected the fitting of the sensor, the alarm is turned off and the “sensor off” message disappears (step 423 /yes). The process then restarts the timer (step 424 ) and continues to monitor for the expiration of the timer (step 419 ). Thus, in the embodiment of FIG. 4 the sensor alarm handling mode of FIG. 2 involves that the timer is paused for the period during which the sensor is not properly fitted at the measurement site.
[0037] If the two usage identifiers are found to be inconsistent in step 412 , the measurement is rejected and the user is informed of the situation (step 413 ). The information displayed to the user may include a request to change the sensor.
[0038] In the embodiment of FIG. 4 , the site timing functionality is provided with two trigger events; first an “authentication ok” signal obtained from step 412 /yes, which triggers the retrieval of the timer settings and the display of the timer bar on the screen and then the actual start event, i.e. the start of the actual measurement, that starts the timer. Consequently, a start event may comprise a sequence of predetermined occurrences, the start event being detected upon completion of the sequence. A particular event may also trigger different operations depending on the time of the event. For example, the cessation of the “sensor off” message may be regarded as a start event (or as a part of a start event) that starts a timer period at the beginning of a measurement session, while the detection of the cessation may restart a paused timer in the middle of the measurement session.
[0039] FIG. 5 illustrates another example of the operation of the site timing algorithm. It is assumed here that a pulse oximeter sensor is connected to the monitor unit. The control and processing unit first monitors if a new sensor is connected to the monitoring unit (step 51 ). When a new pulse oximeter sensor is detected, the control and processing unit further monitors when the actual measurement starts, i.e. when reception of plethysmographic data from the subject starts (step 52 ). Upon start of the measurement, the control and processing unit creates and starts a first timer (step 53 ). The first timer may be a timer that is advanced continuously for a preset period, such as 4 hours. The process then monitors the plethysmographic waveform and determines perfusion index (PI), which is a relative assessment of the pulse strength at the measurement site. As PI is primarily affected by the amount of blood flow at the measurement site, lowered PI is indicative of an increased risk of skin injury. The process therefore starts to monitor at step 54 whether PI remains above a given threshold value, which may be defined as a certain percentage of the original patient-specific value, for example. If it is detected at step 54 that PI drops below the threshold, the process may create and start a second timer (step 55 ). The second timer may advance only when PI remains below the threshold, thereby to track the total time that PI has remained under the threshold. Further, the period set for the second timer may depend on the time elapsed in the first timer. For example, the period of the second timer may be set to a period corresponding to a predefined proportion of the time period left in the first timer. When either of the two timers expires, the process indicates to the user that the location of the sensor should be changed (step 56 ). The reason for the location check may also be indicated.
[0040] In FIG. 5 , the handling of sensor alarm events is not shown. However, sensor alarm events may be detected and processed similarly as in the embodiments of FIGS. 2 and 4 .
[0041] Instead of starting and advancing a second timer, the process may also advance the first timer at a higher rate in step 55 . That is, the drop of PI below the threshold may be regarded as a start event that starts a new timer or as a control event that controls an existing timer. Generally, it is not necessary to generate multiple timers but different events may be used as (predetermined) control events that control a single timer depending on the skin injury risk associated with the event. In addition to, or instead of, monitoring PI, the process may also monitor sensor motion, since motion of the sensor may also increase the risk of a skin injury. Therefore, a separate motion timer may advance when motion is detected in the plethysmographic signal data or the process may advance the first timer at a higher rate when motion is detected. A further parameter indicative of changes in the skin injury risk is a temperature value indicative of the temperature of skin surface at the measurement site. Thus, one or more parameters that correlate with a risk of a skin injury may be acquired, by deriving one or more parameters from the actual physiological signal data and/or by obtaining one or more parameters from external sources, such as an external temperature sensor or an external acceleration transducer.
[0042] FIG. 6 illustrates one embodiment of a low power pulse oximeter system provided with site timing functionality. The system comprises a smart sensor 600 attachable to a subject and a central unit 607 adapted to communicate with the smart sensor. The smart sensor normally includes two or more light emitting elements, such as LEDs, and at least one photo detector 603 . It is assumed here that the smart sensor includes two LEDs 602 , each emitting light at a dedicated wavelength. The wavelength values widely used are 660 nm (red) and 940 nm (infrared). The light emitted by the LEDs and propagated through (or reflected from) the tissue, such as finger 608 , is received by the photo detector 603 which converts the optical signal received at each wavelength into an electrical signal.
[0043] The smart sensor further comprises a control unit 601 , such as a microcontroller, that controls the LEDs through a LED control interface 604 , and an A/D converter 605 that converts the electrical signal obtained from the photo detector into digitized format. The control unit receives the (photo) plethysmographic signal data from the A/D converter, and there may also be an amplifier between the photo detector and the control unit. The control unit is connected to a radio frequency interface 606 for transmitting the plethysmographic signal data to the central unit 607 and for receiving data from the central unit. Thus, a two-way communication link 609 exists between the smart sensor and the central unit.
[0044] For controlling the LEDs, the control unit 601 is provided with a LED control algorithm 610 configured to control, when executed by the control unit, the LEDs 602 through the LED control interface 604 . The central unit 607 is provided with a LED control algorithm 611 that co-operates with algorithm 610 , and with an SpO2 calculation algorithm 612 . The algorithms 610 and 611 handle the synchronization of the LED operation with the plethysmographic waveforms and the SpO2 calculation algorithm 612 is configured to determine the SpO2 values.
[0045] In various embodiments of the pulse oximeter system of FIG. 6 , plethysmographic signal data may be collected only during certain waveform sections. Therefore, during the recording of the data the LEDs may be switched on during the said sections only. In some embodiments of the system, however, the LEDs may also be used to synchronize the data collection with the said sections. The functionalities of the LED control algorithm 610 depend on the synchronization mechanism and on how the synchronization functionalities are divided between the sensor and the central unit, i.e. between algorithms 610 and 611 .
[0046] In practice, the smart sensor of FIG. 6 may be divided into two different units; a sensor 613 comprising the optical components of a conventional sensor, i.e. LEDs 602 and photo detector 603 , and a base unit comprising the non-optical components of the smart sensor 600 . The sensor 613 , which is attachable to the subject, may be connected through a short cable to the base unit. In this way, the smart sensor may be divided between a disposable unit, i.e. sensor 613 , and a unit with longer durability, i.e. the base unit.
[0047] The site timing algorithm 614 may reside either in the control unit 601 or in the central unit 607 , but the functionality may also be distributed between the two units. If the algorithm resides in the control unit 601 , the base unit (or the disposable unit) may be provided with a visual indicator 615 , such as LED, that indicates the need to change the sensor to another measurement site in response to a timer expiration. The sensor/base unit may also be provided with a start button 616 , the pressing of which is regarded as a start event.
[0048] In the above embodiments, the notification generated upon timer expiration is a user notification given to the user. However, the notification may also be a machine-interpretable notification based on which the apparatus automatically changes the sensor site, i.e. the active sensor from which the physiological signal is measured. This embodiment may be used especially if the cooling down of the sensor, which occurs as a result of the sensor deactivation, is a major factor that prevents a skin injury from developing. Although machine-interpretable notifications may be invisible to the user, the apparatus may indicate the sensor that is active at any given time. Below, a notification indicative of a need to change sensor placement, i.e. the site of the active sensor, may thus refer to a user notification recommending that the sensor placement be changed or to a machine-interpretable notification based on which the apparatus is adapted to change the active sensor.
[0049] In terms of sensor placement control, the functionalities of the control and processing unit (or the control unit of the sensor) may be divided into the units shown in FIG. 7 . An event detection unit 71 is configured to monitor the occurrence of at least one predetermined event and to indicate the detection of a particular event to a timer control unit 72 . Generally, the events monitored may be divided between start events and control events and one or more start events may start the same timer. However, in a simple embodiment the control events may be omitted and only one predetermined start event, such as the start of the measurement or the pressing of a start button, may be used. In a further simple embodiment, only one control event, a user-originated timer control, may be used in addition to a single predetermined start event. The timer control unit is configured to start a timer 73 in response to a start event and control a timer in response to a control event. The control may include control of the settings 74 of one or more timers in response to user input through user interface 104 . That is, a specific user action may be regarded as a predetermined control event. An indication unit 75 is configured to produce the notifications and timer state information based on the data obtained from the timer control unit. The notifications may be supplied to the user interface or to the control unit, depending on whether user notifications or machine-interpretable notifications are used. As obvious from the embodiment of FIG. 5 , the event detection unit may further be configured to monitor a physiological signal, such as a plethysmographic signal, derive a parameter from the physiological signal, and detect a predetermined event when the parameter fulfills predetermined criteria, such as crossing of a predetermined threshold value. The parameter may be any parameter that correlates with the skin injury risk, such as PI parameter or motion parameter, and several different parameters may be determined. The parameter(s) may also be obtained from a separate measurement device, such as a motion detector unit (acceleration transducer) or a temperature sensor.
[0050] A physiological monitoring apparatus, such as a pulse oximeter, may also be upgraded to a device provided with the site timing functionality. Such an upgrade may be implemented by delivering to the apparatus a software module that enables the device to detect at least one predetermined event, start at least one timer in response to the detection of a predetermined start event, and to generate a notification to the user in response to a timer expiration. The software module may be delivered, for example, on a data carrier, such as a CD or a memory card, or through a telecommunications network. The software module may thus include the site timing algorithm shown in FIGS. 1 , 3 , and 6 and it may also include any one or more of the above features.
[0051] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural or operational elements that do not differ from the literal language of the claims, or if they have structural or operational elements with insubstantial differences from the literal language of the claims. | A method for controlling sensor placement time, a physiological measurement apparatus and a sensor and computer program product for a physiological measurement apparatus are disclosed. In order to prevent skin injuries, occurrence of at least one predetermined event is monitored, wherein the at least one predetermined event comprises at least one predetermined start event. Upon detection of any of the at least one predetermined start event, a respective timer is started, thereby to start at least one timer, wherein each timer is provided with dedicated timer settings. Upon expiration of any of the at least one timer, a notification indicative of a need to change sensor placement is generated. | 0 |
NOTICE OF COPYRIGHT
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to any reproduction by anyone of the patent disclosure, as it appears in the United States Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever.
BACKGROUND OF THE PRESENT INVENTION
1. Field of Invention
The present invention relates to flagpoles and more particularly, to a retractable flagpole assembly, which can be set between an extended operative position and a received non-operative position and, which prevents the flag from tangling on the flagpole.
2. Description of Related Arts
A conventional flagpole is known having two receiving portions disposed at different elevations at the top side thereof for the fastening of the top and bottom corners of the fixation end (opposite to the fly end) of a flag. This arrangement cannot prevent the flag from tangling on the flagpole when the flag is flying in the breeze. To avoid the tangled flag problem, a tangle free flagpole is known using two or three swivel pivot holders to secure the flag to the flagpole and a link to link the swivel pivot holders. When the flag is flying in the breeze, the swivel pivot holders can be synchronously turned with the link about the flagpole, preventing the flag from tangling on the flagpole. Taiwan Patent M263591 discloses a similar design. However, this design does not allow the use of a retractable pole. If a retractable pole consisting of multiple parts is used, the swivel pivot holders shall have to be fastened to the top piece of the multiple parts of the retractable pole, however, the swivel pivot holders will become a barrier to stop the top piece of the multiple parts of the retractable pole from being inserted into the inside of the other parts. Therefore, this problem must be settled.
SUMMARY OF THE PRESENT INVENTION
The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a retractable flagpole assembly, which is retractable and can prevent the flat from tangling.
To achieve this and other objects of the present invention, a retractable flagpole assembly comprises a retractable flagpole, a top pivot holder rotatably capped on the top rod of the retractable flagpole and provided with a hanging lug for securing an inner top end of a flag, an end block spaced below the lower pivot holder and provided with a hanging lug for securing an inner bottom end of the flag, a link coupled between the top pivot holder and the end block, and a lower pivot holder rotatably sleeved onto the retractable flagpole and axially movable along the link and lockable to the end block.
Further, the top pivot holder comprises an axle sleeve vertically disposed at one lateral side thereof. The axle sleeve comprises an axial through hole extending through opposing top and bottom ends thereof. The axial through hole of the axle sleeve of the top pivot holder comprises an upper crossed hole portion, a lower flat hole portion, and a stop edge defined between the upper crossed hole portion and the lower flat hole portion. The link comprises a flat top end portion vertically upwardly inserted through the axial through hole of the axle sleeve of the top pivot holder and stopped at the top side of the stop edge of the axle sleeve of the top pivot holder after a rotary motion of the link relative to the top pivot holder.
Further, an upper end plug is plugged in the upper crossed hole portion of the axial through hole of the axle sleeve of the upper pivot holder.
Further, the end block comprises an axial through hole extending through opposing top and bottom ends thereof. The axial through hole of the end block comprising a lower crossed hole portion, an upper flat hole portion, and a stop edge defined between the lower crossed hole portion and the upper flat hole portion. The link further comprises a flat bottom end portion vertically upwardly inserted through the axial through hole of the end block and stopped at the bottom side of the stop edge of the end block after a rotary motion of the link relative to the end block.
Further, a lower end plug is plugged in the lower crossed hole portion of the axial through hole of the end block.
The retractable flagpole assembly further comprises an anchor. The anchor comprises a round tube fastened to the bottom end of the retractable flagpole, an angle plate fixedly fastened to the bottom end of the round tube and terminating in a pointed portion for fastening into the ground, and a force-applying portion perpendicularly extended from an upper part of the angle plate for operation by hand or foot or hammer.
Further, the lower pivot holder comprises a tubular body sleeved onto the retractable flagpole, and locking means adapted to lock the link to the tubular body.
Further, the lower pivot holder comprises a tubular body sleeved onto the retractable flagpole. The locking means comprises two fixed sleeve components fixedly connected to the periphery of the tubular body at different elevations and sleeved onto the link, and a movable sleeve component coupled between the two fixed sleeve components and sleeved onto the link and rotatable relative to the two fixed sleeve components and the link between a locking position to lock the link to the tubular body and an unlocking position for allowing the lower pivot holder to be moved axially relative to the link.
Further, the movable sleeve component comprises an eccentric hole extending through opposing top and bottom ends thereof for the passing of the link. The movable sleeve component is forced into friction engagement with the periphery of the link and the periphery of the tubular body when moved to the locking position.
The retractable flagpole assembly further comprises a first coupling means located on the bottom end of the lower pivot holder, and a second coupling means located on the top end of the end block and detachably engageable with the first coupling means.
In one embodiment, the first coupling means comprises at least one coupling groove, and the second coupling means comprises at least one coupling block detachably engageable with the at least one coupling groove.
In another embodiment, the first coupling means comprises at least one coupling block, and the second coupling means comprises at least one coupling groove detachably engageable with the at least one coupling block.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective exploded view of a retractable flagpole assembly in accordance with the present invention.
FIG. 2 is a perspective exploded view of the flagpole assembly in accordance with the present invention.
FIG. 3 is a schematic sectional assembly view of a part of the flagpole assembly in accordance with the present invention.
FIG. 4 is a schematic sectional view of the present invention, illustrating the flagpole adjusted from the received non-operative condition to the extended operative condition.
FIG. 5 is a schematic sectional applied view of the present invention, illustrating the anchor of the flagpole assembly fastened to the ground.
FIG. 6 is a schematic sectional view of the present invention, illustrating the flagpole adjusted from the extended operative condition to the received non-operative condition.
FIG. 7 is a schematic exploded view of a part of an alternate form of the retractable flagpole assembly in accordance with the present invention.
FIG. 8 is a schematic sectional assembly view of a part of the retractable flagpole assembly shown in FIG. 7 .
FIG. 9 is a schematic drawing of a part of the retractable flagpole assembly shown in FIG. 7 , illustrating the movable sleeve component of the axle sleeve of the lower pivot holder rotated relative to the fixed sleeve components.
FIG. 10 is a schematic drawing of a part of the retractable flagpole assembly shown in FIG. 7 , illustrating the movable sleeve component of the axle sleeve forced into engagement with the link and the periphery of the tubular body of the lower pivot holder.
FIG. 11 is a schematic perspective exploded view of a part of another alternate form of the present invention.
FIG. 12 is a perspective assembly view of the alternate form shown in FIG. 11 .
FIG. 13 is a sectional view of the structure shown in FIG. 12 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , a retractable flagpole assembly in accordance with the present invention is shown. The flagpole assembly comprises a retractable flagpole 1 , a top pivot holder 2 , an end block 3 , a link 4 , a lower pivot holder 5 , and an anchor 6 .
The retractable flagpole 1 is an adjustable in length, comprising a top rod 11 , an intermediate rod 13 and a bottom rod 12 (see FIG. 1 and FIG. 2 ). The top rod 11 has a rounded top end 111 , and a top screw hole 112 located at the center of the rounded top end 111 for the fastening of a bottom screw rod 71 of a finial 7 (see FIG. 3 ).
The top pivot holder 2 is a hollow cylindrical cap member rotatably capped on the rounded top end 111 of the flagpole 1 (see FIG. 3 ), comprising a flat top end wall 24 supported on the rounded top end 111 of the flagpole 1 , a top through hole 25 cut through the flat top end wall 24 at the center for the passing of the bottom screw rod 71 of the finial 7 , an axle sleeve 22 vertically disposed at one lateral side thereof, and a hanging lug 21 formed integral with the periphery of the axle sleeve 22 for the fastening of an upper hook member of a flag 8 . The axle sleeve 22 defines an axial through hole 23 (see FIG. 2 ). The axial through hole 23 comprises an upper crossed hole portion 232 , a lower flat hole portion 231 , and a stop edge 233 defined between the upper crossed hole portion 232 and the lower flat hole portion 231 . Further, after installation of the bottom screw rod 71 of the finial 7 in the top through hole 25 of the top pivot holder 2 , a gap G is left between the finial 7 and the flat top end wall 24 of the top pivot holder 2 , allowing free rotation of the top pivot holder 2 relative to the retractable flagpole 1 (see FIG. 3 ).
The end block 3 comprises a hanging lug 31 formed integral with the periphery thereof for the fastening of a lower hook member of the flag 8 (see FIG. 2 ), and an axial through hole 32 extending through opposing top and bottom ends thereof. The axial through hole 32 comprises a lower crossed hole portion 322 , an upper flat hole portion 321 , and a stop edge 323 defined between the lower crossed hole portion 322 and the upper flat hole portion 321 .
The link 4 is coupled between the top pivot holder 2 and the end block 3 , comprising a flat top end portion 41 and a flat bottom end portion 42 (see FIG. 2 ). The flat top end portion 41 and flat bottom end portion 42 of the link 4 are disposed on the same plane. The flat top end portion 41 of the link 4 is upwardly inserted through the lower flat hole portion 231 and upper crossed hole portion 232 of the axial through hole 23 of the top pivot holder 2 , and then the link 4 is rotated through an angle relative to the top pivot holder 2 , enabling the flat top end portion 41 of the link 4 to be stopped at the top side of the stop edge 233 in the axial through hole 23 of the top pivot holder 2 (see FIG. 3 ). The flat bottom end portion 42 of the link 4 is downwardly inserted through the upper flat hole portion 321 and lower crossed hole portion 322 of the axial through hole 32 of the end block 3 , and then the end block 3 is rotated through an angle relative to the link 4 , enabling the flat bottom end portion 42 of the link 4 to be stopped at the bottom side of the stop edge 323 in the axial through hole 32 of the end block 23 (see FIG. 3 ) to hold the end block 3 in place. Thereafter, an upper end plug 26 and a lower end plug 33 are respectively fastened to the axial through hole 23 of the top pivot holder 2 and the axial through hole 32 of the end block 3 to prevent displacement of the link 4 relative to the top pivot holder 2 or the end block 3 .
The lower pivot holder 5 comprises a tubular body 51 sleeved onto the retractable flagpole 1 , and an axle sleeve 52 vertically formed integral with the periphery of the tubular body 51 . The link 4 is inserted through the axle sleeve 52 of the lower pivot holder 5 before connection between the link 4 and the top pivot holder 2 or end block 3 . After installation, the lower pivot holder 5 is coupled to the link 4 and axially movable along the link 4 between the top pivot holder 2 and the end block 3 (see FIG. 4 ).
The anchor 6 comprises a round tube 61 (see FIG. 1 ), and an angle plate 62 fixedly fastened to the bottom end of the round tube 61 and terminating in a pointed portion 63 for fastening to the ground (see FIG. 5 ), and a force-applying portion 64 perpendicularly extended from an upper part of the angle plate 62 for operation by hand or foot or hammer to fasten the pointed portion 63 into the ground.
As stated above, the link 4 is coupled between the top pivot holder 2 and the end block 3 , the top pivot holder 2 and the end block 3 can be rotated relative to the flagpole 1 synchronously during application (see FIG. 3 ), therefore, when the flag 8 is flying in the breeze, the top pivot holder 2 and the end block 3 can be rotated relative to the flagpole 1 synchronously, preventing the flag 8 from tangling. Further, the lower pivot holder 5 is coupled to the link 4 and axially movable along the link 4 relative to the flagpole 1 between the top pivot holder 2 and the end block 3 (see FIG. 4 ). Thus, when extending out the retractable flagpole 1 from a received non-operative condition to an extended operative condition or retracting it from the extended operative condition to the received non-operative condition, the lower pivot holder 5 will be stopped by the top pivot holder 2 or the end block 3 (see FIG. 4 and FIG. 6 ), and the flag 8 is kept secured to the top pivot holder 2 and the end block 3 . Thus, the user can roll up the flap 8 on the flagpole 1 conveniently after the retractable flagpole 1 is set in the received non-operative condition.
FIGS. 7 and 8 illustrate an alternate form of the lower pivot holder 5 . According to this alternate form, the axle sleeve 52 of the lower pivot holder 5 comprises two fixed sleeve components 521 fixedly connected to the periphery of the tubular body 51 at different elevations and axially aligned, and a movable sleeve component 53 rotatably coupled between the two fixed sleeve components 521 . The movable sleeve component 53 comprises an eccentric hole 531 extending through opposing top and bottom ends thereof. The link 4 is inserted through the eccentric hole 531 of the movable sleeve component 53 . After insertion of the link 4 through the fixed sleeve components 521 and the eccentric hole 531 of the movable sleeve component 53 , the movable sleeve component 53 is rotated through an angle relative to the fixed sleeve components 521 to force the inside wall of the movable sleeve component 53 against the link 4 . At this time, the periphery of the movable sleeve component 53 is forced into friction engagement with the tubular body 51 (see FIGS. 9 and 10 ), and therefore the lower pivot holder 5 is locked to the link 4 , allowing the lower pivot holder 5 to be moved with the top pivot holder 2 , the end block 3 and the link 4 relative to the retractable flagpole 1 synchronously.
FIG. 11 illustrates another alternate form of the present invention, which enables the lower pivot holder 5 to be moved axially up and down relative to the link 4 and turned with the top pivot holder 2 , the end block 3 and the link 4 about the retractable flagpole 1 synchronously. According to this alternate form, a female coupling portion 54 (for example, coupling groove) is located on the bottom end of the lower pivot holder 5 , and a male coupling portion 34 (for example, coupling block) is located on the top end of the end block 3 and detachably engageable into the female coupling portion 54 . Thus, when moving the lower pivot holder 5 downwardly along the retractable flagpole 1 toward the end block 3 , the female coupling portion 54 can be forced into engagement with the male coupling portion 34 (see FIGS. 12 and 13 ) to lock the top pivot holder 2 , the lower pivot holder 5 , the end block 3 and the link 4 together. When unlocking the lower pivot holder 5 from the end block 3 and the link 4 , move the lower pivot holder 5 upwardly to disengage the female coupling portion 54 from the male coupling portion 34 . Further, when released the lower pivot holder 5 from the hand, the lower pivot holder 5 will be forced by its gravity to move downwardly into engagement with the end block 3 . Further, snap, buckle or any of a variety of other fastening means may be used to substitute for the male coupling portion 34 and the female coupling portion 54 for detachably locking the lower pivot holder 5 and the end block 3 together.
By means of moving the lower pivot holder 5 to force the female coupling portion 54 into engagement with the male coupling portion 34 or to disengage the female coupling portion 54 from the male coupling portion 34 , the lower pivot holder 5 can be conveniently locked to or unlocked from the end block 3 . Thus, when pulled the top rod 11 out of the intermediate rod 13 and the bottom rod 12 to extend out the retractable flagpole 1 , the lower pivot holder 5 is then forced into engagement with the end block 3 . At this time, the lower pivot holder 5 can be turned with the top pivot holder 2 , the end block 3 and the link 4 about the retractable flagpole 1 synchronously, preventing the flag 8 from tangling on the retractable flagpole 1 . When the lower pivot holder 5 is disengaged from the end block 3 , the lower pivot holder 5 can be moved axially relative to the link 4 , allowing the top rod 11 to be received with the intermediate rod 13 into the inside of the bottom rod 12 . Briefly speaking, the lower pivot holder 5 can be locked to the end block 3 and the link 4 , preventing the flag 8 from tangling on the retractable flagpole 1 . When unlocked the lower pivot holder 5 from the end block 3 , the retractable flagpole 1 can be received from the extended operative condition to the received non-operative condition.
Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims. | A retractable flagpole assembly includes a retractable flagpole, a top pivot holder rotatably capped on the top rod of the retractable flagpole and provided with a hanging lug for securing an inner top end of a flag, an end block spaced below the lower pivot holder and provided with a hanging lug for securing an inner bottom end of the flag, a link coupled between the top pivot holder and the end block, and a lower pivot holder rotatably sleeved onto the retractable flagpole and axially movable along the link and lockable to the end block. | 4 |
BACKGROUND OF THE INVENTION
The present invention is directed to a universal remote control system which includes the use of a releasable readable media storage device, such as a Smart Card (herein referred to as “Smart Card” or “Card”), in transferring information and data to/from the remote control. A typical releasable readable media storage device is characterized as a device with a non-volatile memory and, in many cases, a microprocessor, which can be releasably mated with a reading device. For example, a Smart Card includes one or more chips (integrated circuits) that are imbedded in the Card for receiving and storing information and data. This information and data can then be “read” from or “written” to the Smart Card.
Smart Cards are in wide spread use and can be broadly classified as either contact, contactless or hybrid Cards. The contact type of Card utilizes appropriate technology to establish a physical electrical contact with an associated device which can read the information on the Smart Card. In the contactless type, the Card is passed over the appropriate technology to be powered by suitable inductive coils and the Card then sends a signal through capacitive plates. A hybrid type of Card is a combination of the two foregoing types. While any of the foregoing types of Cards could be used in the present invention, the preferred embodiment utilizes a contact type Card which connects to an associated remote control, as will be described. Other types of readable media storage devices which can be used in the present invention include virtually any type of releasable media storage device, and the invention is not limited to the use of a Smart Card.
The present invention relates to a user-configurable universal remote control having its device codes, that is the sets of code data needed to operate various electronic devices, supplied from a releasable readable media storage device. In the preferred embodiment, this readable media storage device is a Smart Card. The universal remote control unit is provided or sold to a particular user essentially “empty” of the code data needed to configure the remote control to that user's television, video cassette recorder (“VCR”), cable box, Internet access device or other electronic device. The universal remote control is built with a reader slot or port into which the user can insert separately purchased “device library” Cards which contain the sets of code data necessary to configure the remote control to operate all or some of those electronic devices the user wishes to control. Additional sets of code data can be added to the remote control any time the user obtains a new electronic device, up to the maximum capacity of the remote control, through the use of additional Smart Cards.
The releasable readable media storage device, i.e., Smart Card, to be utilized in the present invention contains a compilation of the device codes suitable for use with a particular universal remote control, and allows a one time transfer of a single device code (i.e., the set of code data needed to remotely operate a particular electronic device) from the readable media storage device into the remote control's on board, non-volatile memory. In the preferred embodiment, a Smart Card constructed of low cost material is utilized and is good for only one use. In one alternative embodiment, each Smart Card is designed for more than one use. In another alternative embodiment, the universal remote control system of the present invention is designed so that information/data from the remote control can be downloaded into and remain stored in a releasable readable media storage device, e.g, a certain device code may be transferred from the remote control to a Smart Card. In a more complicated embodiment involving two-way communication between the remote control and an electronic device, the universal remote control of the subject invention contains an infrared receiver for the purpose of receiving information from a television, computer or other electronic device and a means for transferring such information into the memory of a readable media storage device releasably mateable with that remote control. In such an embodiment, information/data can be transferred from a user's electronic device to the remote control to the readable media storage device, e.g. a video coupon appearing on a television could be transferred from the television to the remote control and then to a Smart Card for later use in a store or other shopping facility where the coupon could be redeemed.
In the preferred embodiment, to set up the universal remote control to operate a particular electronic device, a Smart Card must be inserted into a reader slot or port in the remote control. The location of this reader slot can vary depending on the design requirements of a particular universal remote control. Once the Card is inserted into the reader slot or port, the user is able to experiment with various device codes until he finds the one which will operate his electronic device. Once the user locks in a particular device code, that device code (i.e., set of code data) is transferred into the remote control's non-volatile memory and the balance of the code data on the Card is either erased or blocked from further use.
Another application of the present invention is in the cable television industry. Operators which provide cable or satellite television service to a number of subscriber's receiver sets are faced with the necessity of maintaining control of the service provided to each of the individual sets. Conversely, subscribers to such cable and satellite services each have individual needs and requirements as to the channels, features and functions available on and to their television sets. For example, a cable or satellite service provider offers various types of services to its television subscribers and each subscriber normally has a choice of selecting what channels and/or what programs he or she desires to receive. Accordingly, a service provider must be able to provide the desired service to each subscriber, and the provider must be able to keep track and control over the type of service provided to each subscriber. A subscriber may also want to periodically change or vary the services or functions available on his or her set, or to add equipment to his or her entertainment system.
At present there are various ways for the service providers to track and maintain control of such service, and various ways for the subscriber to change the service he or she receives or the functions available to him or her. However, the known methods and apparatus for maintaining such control and/or making such changes are relatively expensive and cumbersome. The functions, services and equipment currently known are not readily flexible to meet the individual subscriber's needs. The present invention addresses these disadvantages of these known methods and apparatus.
In the system, method and apparatus of the present invention, the user's remote control unit has slots or ports for accommodating one or more releasable readable media storage devices. The releasable readable media storage device of the present invention is utilized in a unique manner with the remote control to provide code data to the remote control and to provide control commands and programming data to the associated electronic devices, as will be described. In addition, the universal remote control system of the present invention can be utilized for two-way communication and used for home shopping, electronic banking, and pay-per-view movie purchase.
BACKGROUND ART
A patent of interest relative to the present invention is U.S. Pat. No. 5,214,622 which discloses a television monitor including a remote control. The remote control is provided with a slot into which memory cards are inserted. The remote control of U.S. Pat. No. 5,214,622 is adapted to use a memory card to provide information which can be transferred between the remote control and the display means. U.S. Pat. No. 5,214,622 is basically directed to providing a calendar timer superimposed on the television display serving as a reference for displaying the information. The remote control also contains a transparent pressure sensitive pad covering a liquid crystal display for inputting hand written information, as well as the standard alpha-numerical and symbol keys for inputting remote control commands such as channel selection, volume control, etc.
Another patent of interest with respect to the present invention is U.S. Pat. No. 5,594,493 which discloses a Smart Card utilized with a television system. The Smart Card disclosed in U.S. Pat. No. 5,594,493 has a photoelectric optical pick-up device embedded in the Card for receiving and storing a signal from the television set. The stored data can be subsequently displayed and read. The Card of U.S. Pat. No. 5,594,493 is used to record data relating to product identification for use in product promotion and sales. The Cards allow advertisers to make special offers of products to the Card holders for use within specific and varied time periods. The patent states that the Card affords a nearly fail safe data transmission via standard computer and television transmission methods.
SUMMARY OF INVENTION
The present invention relates to a user-configurable universal remote control having its device codes, that is the sets of code data needed to operate various electronic devices including Internet access devices, supplied from a releasable readable media storage device. (The system of the present invention can also be utilized with a dedicated remote control wherein the code data needed to operate a particular electronic device is supplied to the dedicated remote control from a releasable readable media storage device.) In the preferred embodiment, this readable media storage device is a Smart Card. The universal remote control is provided or sold to a particular user essentially “empty” of the code data needed to configure the remote control to that user's television, VCR, cable box, Internet access device or other electronic device. The universal remote control is built with a reader slot into which the user can insert separately purchased “device library” Cards which contain the sets of code data necessary to configure the remote control to operate all or some of those electronic devices the user wishes to control. Additional sets of code data can be added to the remote control at any time the user obtains a new electronic device, up to the maximum capacity of the remote control, through the use of additional Smart Cards.
The releasable readable media storage device, i.e., Smart Card, to be utilized in the present invention contains a compilation of the device codes suitable for use with a particular universal remote control, and allows a one time transfer of a single device code (i.e., the set of code data needed to remotely operate a particular electronic device) from the readable media storage device into the remote control's on board, non-volatile memory. In the preferred embodiment, a Smart Card constructed of low cost materials is utilized and is good for only one use. In one alternative embodiment, each Smart Card is designed for more than one use. In another alternative embodiment, the universal remote control system of the present invention is designed so that information from the remote control can be downloaded into and remain stored in a releasable readable media storage device, e.g, a certain device code may be transferred from the remote control to the releasable readable media storage device. In a more complicated embodiment involving two-way communication between the remote control and an electronic device, the universal remote control of the subject invention contains an infrared receiver for the purpose of receiving information from a television, computer or other electronic device and a means for transferring and storing such information in the memory of a readable media storage device releasably mateable with that remote control. In such an embodiment, information can therefore be transferred from a user's electronic device to the remote control to the readable media storage device and stored in that device's memory for later use, e.g. a video coupon appearing on a television could be transferred from the television to the remote control and then to a Smart Card for later use in a store or other shopping facility where the coupon could be redeemed.
To set up the universal remote control to operate a particular electronic device, a releasable readable media storage device, namely a Smart Card, must be inserted into a reader slot in the remote control. The location of this reader slot can vary depending on the design requirements of a particular universal remote control. Once the Card is inserted into the reader slot, the user is able to experiment with various device codes until he finds the one which will operate his electronic device. Once the user locks in a particular device code, that code is transferred into the remote control's non-volatile memory and the balance of the code data on the Card is either erased or blocked from further use using known techniques.
The foregoing system can be used with any electronic device and/or any Internet access device utilizing a remote control. The releasable readable media storage device will include code data for programming the remote control and can also include additional data for controlling the functions and features of the various electronic devices which are controllable by said remote control.
The foregoing features and advantages of the present invention will be apparent from the following more particular description of the invention. The accompanying drawings, listed hereinbelow, are useful in explaining the invention.
DESCRIPTION OF DRAWINGS
FIG. 1 is a front view of a remote control including an internally mounted connector for receiving a releasable readable media storage device which is inserted in a slot opening to the side of the remote control;
FIG. 2 is a side view of the remote control of FIG. 1;
FIG. 3 is a side view of a modification of the remote control of FIG. 1, wherein the connector is formed to be externally mounted on the remote control; the Smart Card is inserted in a slot opening to the top of the remote control;
FIG. 4 shows a drawing of a Smart Card used in the present invention;
FIG. 5A is a schematic diagram of the Smart Card interface as in a remote control;
FIG. 5B is the schematic diagram of FIG. 5A with the addition of an infrared receiver;
FIG. 6 is a flow chart of an operation of the Smart Card of the invention;
FIG. 7 is a flow chart showing the logic implemented to permit the Smart Card and EEPROM interfaces to share common electrical connections;
FIG. 8 shows a series of steps of illustrating the concept of inputting data into an empty remote control; and
FIG. 9 shows a series of steps illustrating the concept of inputting data to enhance the functionality of the remote control.
FIG. 10 shows a series of steps illustrating an electronic transaction utilizing the present invention.
DESCRIPTION OF THE INVENTION
The present invention discloses new and unique uses for a system including a universal remote control and a releasable readable media storage device. The releasable readable media storage device and remote control of the present invention can also provide control for additional equipment including Internet accessible devices. The present invention also enables the releasable readable media storage device to interact with the remote control to vary, change and control the functions of a television receiver, cable box or satellite decoder receiving signals from a service operator. Importantly each user can, by using the appropriate releasable readable media storage device, readily and conveniently configure his remote control to the desired functions, features and channels he obtains from the service operator.
FIGS. 1 and 2 show a remote control 11 , generally patterned after so called universal remote controls of suitable known type. In addition to the standard components and circuitry, remote control 11 includes a connector 12 for a releasable readable media storage device, a Smart Card 15 in the preferred embodiment, which selectively reads and writes to the remote control 11 . Connector 12 comprises a slot or port 14 and a suitable known type socket for connecting to the Smart Card 15 . Slot 14 is molded directly into the case or body 16 of the remote control 11 . Case 16 is preferably made of plastic material. In the embodiment shown, the slot 14 opens to the side of case 16 . Slot or port 14 receives a Smart Card 15 shown in FIG. 4 . Smart Card 15 is approximately 3.3×2.1 inches in size.
Connector 12 can comprise a plurality of slots to accommodate or receive one or more Smart Cards 15 which are inserted in respective slots in the connector 12 . However, in the preferred embodiment and also for purposes of clarity in the drawing, only one slot 14 is indicated. Additional slots as needed may be formed in connector 12 parallel to slot 14 or elsewhere in the remote control 11 .
The electrical and mechanical interface of Smart Card 15 with the remote control 11 conforms to, and complies with, the international standard ISO 7816 for integrated circuit cards which have an interface with electrical contacts. Each slot 14 formed in connector 12 would have a similar interface.
It should be clearly understood that, while the electrical and mechanical interface used in Smart Card 15 is in accordance with ISO 7816 standards, in the preferred embodiment shown the software protocols and data being transferred are unique to the present invention. However, in other applications, the protocol(s) and/or data transferred may correspond to a pre-existing standard format suited to that application, e.g. home banking as explained below.
FIG. 3 shows a modification 11 A of the remote control 11 of FIGS. 1 and 2. In the embodiment of FIG. 3, the connector 12 A is formed essentially as a box externally of the case 16 A and appropriately affixed to the case 16 A. In the embodiment of FIG. 3, the slot 12 A opens upwardly, as indicated by the dotted lines in the Figure, and the Smart Card 15 is inserted into the slot 14 A from the top of the remote control 11 . The operation of the remote control 11 and the Smart Card 15 as depicted in FIG. 3 are the same as for the embodiment of FIGS. 1 and 2.
FIG. 5A shows the electronic circuitry 20 for the remote control 11 and the Smart Card 15 . The circuitry of FIG. 5A, and the operation of the circuitry are well known, hence detailed description is not believed necessary. Microprocessor 26 may be of any suitable known type. The keypad 28 (which includes the various known television TV and VCR function keys depicted in FIG. 1) enables user inputs to microprocessor 26 . Referring to the lower left hand corner of FIG. 5A, the connector 12 receives the Smart Card 15 and connects via leads 23 and 24 to the remote control 15 microprocessor 26 . The connector 12 also supplies power from the remote control batteries 33 to the chip on the Smart Card via connections 34 and 35 . Additionally, a contact is provided within connector 12 , attached to lead 36 , which is used to notify the microprocessor 26 that a Smart Card 15 has been inserted, as is described in greater detail later in conjunction with the flowchart of FIG. 6 . The data in Smart Card 15 selectively control or alter the functionality of the microprocessor 26 in accordance with the data programmed and stored in Smart Card 15 . Microprocessor 26 can also write to Card 15 .
As will be explained hereinbelow, the Smart Card technology of the present invention can be used to enable the remote control to alter various configurable features and/or information in a remote control or on the controlled devices, such as a television set; and, the Smart Card can be used to add code data for different electronic devices to be controlled by a universal remote control. FIG. 5B shows the electronic circuitry of a remote control (as explained above with reference to FIG. 5A) which includes an infrared receiving means 37 .
The flowchart of FIG. 6 describes the operation of the Smart Card 15 and remote control 11 circuitry of FIGS. 5A and 5B. Initially, the microprocessor 26 is in a “sleep,” or shut down mode in order to minimize power consumption and conserve battery life. Insertion of the Smart Card 15 into slot 14 closes a contact which, via transistor 29 and capacitor 30 , generates a pulse on the IRQ—(Interrupt Request) input pin 31 of the microprocessor 26 . Receipt of this signal causes the microprocessor 26 to exit the previously described low power shut down state and begin normal execution. First, the microprocessor 26 inspects the status of the keypad matrix 28 in order to determine if it was “woken up” by the user pressing a key. (If a keypress was the cause of the IRQ signal, the microprocessor 26 would then proceed to execute the indicated remote control function in the normal way.) In the embodiment described in FIG. 6, however, the microprocessor 26 will determine that no key has been pressed, as described in block 1 of FIG. 6 . Initially, the first byte of data on the Smart Card 15 is read and evaluated to determine if the Card 15 is of the correct type. If not, the microprocessor 26 returns to its idle state, as described in block 4 of FIG. 6 . Next, the microprocessor 26 validates the memory block header stored on the Smart Card 15 . This header contains information indicating where in the remote control's non-volatile memory the following Smart Card data bytes are to be stored, and for what purpose. If an invalid header is detected, the microprocessor 26 signals the user (by, for example, flashing the visible LED 32 ), and returns to the idle state, as described in block 7 of FIG. 6 . Once a valid block header has been found, the balance of the data in that block on the Smart Card 15 is copied from the Smart Card 15 to the RAM memory 27 of the microprocessor 26 , and then from there to the designated target address within the remote control's non-volatile memory, as described in blocks 8 and 9 of FIG. 6 . On completion of this transfer, the microprocessor logic returns, as described in block 5 of FIG. 6, to check for another data block contained on the Smart Card 15 . If one is found (as evidenced by a second valid memory block header immediately flowing the end of the first data block), the transfer cycle is repeated. This process continues until no further valid data blocks are found, at which point the microprocessor 26 now checks the Card type previously acquired to determine if the Smart Card 15 currently inserted in connector 12 is the “single use” type. If so, the microprocessor 26 writes data to the memory contained on the Smart Card 15 in order to erase or otherwise disable future use of the Card 15 , as described in blocks 10 and 11 of FIG. 6 . The microprocessor 26 then signals the user and returns to the idle state as described in block 7 of FIG. 6 . In certain applications of the present invention, it may be desirable to provide additional security to the information and data stored on said Smart Card. In connection with such embodiments of the present invention, various security and encryption systems, including but not limited to a requirement that the user first activate the Smart Card through the use of a unique personal identification number (“PIN”) keyed in by the user, have been proposed or implemented and are well known in the art.
In the preferred embodiment shown in FIG. 5A, the Smart Card interface signals 23 and 24 are shared with those of the remote control's non-volatile memory EEPROM 27 . Since the Smart Card 15 and EEPROM 27 have similar electrical interfaces, this allows common firmware code and microprocessor input/output pins to be used to communicate with both devices. Accordingly, a circuit and program logic must be provided to select which device is active at which time. This is accomplished by connecting an input/output port pin 38 on the microprocessor 26 in such a manner that when it is in one state it disables the onboard EEPROM 27 via its enable/disable pin 25 while simultaneously enabling output of the clock signal 24 to the Smart Card connector via transistor 39 , while in the other state it enables the onboard EEPROM 27 while disabling the clock output to the Smart Card connection. The flowchart of FIG. 7 describes how this is accomplished by the firmware during the process of reading data from the Smart Card 15 , e.g. while performing the functions shown in blocks 2 , 5 and 8 of FIG. 6 . The same process would be performed by the firmware in order to select the Smart Card 15 as a target to write data.
A basic concept of one embodiment of the present invention is to provide a standardized remote control 11 with separately available code data for operating different electronic devices. Various Smart Cards are made available for VCRs, for televisions, for stereos, etc. Each Smart Card 15 in the library has code data and programming to control different features, functions and equipment, such as on the television, the VCR and stereo in a user's home entertainment system.
In one embodiment, a user has a remote control 11 which is capable of controlling six devices. Initially the user may acquire “device library cards,” to thereby provide code data to control three of the six possible devices supported by the remote control 11 . If the user subsequently acquires a digital video disc (“DVD”), he can obtain the appropriate Smart Card for controlling the DVD via the remote control 11 .
In the embodiment described in FIG. 8, the remote control 11 is essentially empty of code data. A Smart Card is provided to enable and control the features and equipment of the individual user. In this embodiment, the remote control 11 is essentially passive and is activated by a selected Smart Card 15 . As depicted in FIG. 8, the user obtains and inserts the desired Smart Card into slot 12 of the remote control 11 . The user selects the device code that matches his equipment to load the code data and programming for the selected functions and equipment into the remote control 11 . Once the user locks in a particular device code that code alone is transferred into the remote control 11 , and the Card may be erased or disabled.
The user separately acquires Smart Cards 15 to configure the remote control 11 for exactly those items of service, equipment, or channels he wishes to control. New items, features, functions and equipment are added at any time, up to the maximum capacity of the remote control 11 .
FIG. 9 depicts a second embodiment in which the remote control 11 is preloaded with code data for basic functions and/or equipment. To enable the user to enhance his equipment, Smart Cards are made available that allow purchase of additional function groups of the user's choice or option such as PIP, menu, surround sound adjustments, etc. Also, the remote control 11 may be pre-loaded with a universal library for the basic devices (televisions, VCRs, cable boxes) together with Cards to enable operation of individual additional equipment (DVD, satellite, etc.) as the user adds this equipment to his entertainment system.
The Smart Cards 15 can be designed to allow a single or one time transfer of code data from the Smart Card into the onboard, non-volatile memory of the remote control 11 . Since a Smart Card can be configured to provide essentially a single use it may be fabricated of low-cost materials to be relatively inexpensive. A one-time use capability of the Smart Card 15 acts as a validity and security check to assure that only authorized devices or functions are controlled or changed by a Smart Card 15 . After use, the Smart Card 15 may be discarded. In a modification of the foregoing embodiment, the Smart Card 15 is erased after entry of its input to the remote control 11 , and thereafter the “blank” Smart Card 15 may be recorded and reprogrammed for further use.
By use of the Smart Card technology of the present invention the user can conveniently add to the devices operated by his remote control 11 and the capability of his cable system. For instance, during the hockey season the user can sign on to receive the desired various sports channels for a limited time period. For such use, the cable provider mails an updated Smart Card 15 to the user and the user inserts the Smart Card 15 into the remote to enable his or her system to receive the desired sport channels for that limited period.
As stated above, remote controls 11 are fabricated with features that are enabled or disabled, and various built-in features may be enabled or disabled via Smart Card 15 loaded information. For the cable/satellite service provider, this means that they can selectively enable/disable various buttons or functions on the remote control 11 , depending on what the individual customer has requested. Further this allows a distinct pricing of individual features such as sleep timer, time delay macro playback, favorite channel scan etc.
The Smart Card 15 can be updated to reflect changes in channel line up. A cable or satellite service provider who offers direct channel access keys on its remote control could simply mail an inexpensive Smart Card 15 out to all users whenever the channel line up changes. Thus, the Smart Card 15 becomes the means for delivery of upgraded subscription information, and can be used to modify a customer's service and update the remote control 11 as well.
Since the remote control 11 can transfer data into a Smart Card 15 , Smart Cards are provided that limit access to a particular feature or television program, e.g. five pay-per view movies, monthly or special sport coverage, etc. The Smart Card 15 can, in effect, provide a credit card type of transaction. The remote control 11 is coded to send a particular control signal to the receiver a pre-set number of times, and can specify the data to send. The remote control 11 updates and decrements the authorized number in the Smart Card 15 each time the feature is used, and terminates when the count reaches zero. Alternatively, the remote control 11 can load the counter updated information from the Smart Card 15 into its own internal storage and operated therefrom. In this latter case, after transfer of the information, the Smart Card 15 is erased or disabled, and the card can be discarded.
Another significant use for Smart Card system of the present invention is to limit access to programs of different viewer rating. For example, children in a household have a Smart Card 15 that permits them to view selected programs on the cable system, or to access limited sites on the Internet. In contrast, the parents have Smart Cards with a broader choice of TV programs and/or an unrestricted access to the Internet.
The flowchart in FIG. 10 depicts another type of operation of the Smart Card 15 , when used in a remote control 11 with electronic circuitry such as in shown in FIG. 5B, which includes an infrared receiver 37 in addition to the usual infrared transmitter. The addition of an infrared receiver 37 enables the microprocessor in the remote control 11 to engage in bi-directional communication with other devices such as a cable box, DBS receiver, Internet access device or specialized terminal device (referred to hereafter as “base unit”). There are many different methods and techniques for formatting and modulating data for transmission via infrared or other medium, all of which are well known and are hence not described here. It will also be appreciated that although the preferred embodiment uses infrared to implement this bi-directional communication, similar results could be obtained using other transmission technologies such as radio frequency, ultrasonic, etc.
The Smart Card transaction is initiated by insertion of the Card 15 in the same way as previously described in conjunction with the flowchart of FIG. 6 . This is described in blocks 1 through 4 of FIG. 10 . Once the microprocessor 26 has determined that the card type is “interactive” it enters a loop in which it successively checks for user keyboard 28 input (block 5 ), checks the infrared receiver 37 for data from the base unit (blocks 6 and 7 ), verifies that the Smart Card 15 is still inserted in the slot 14 (block 15 ), and repeats this sequence until either the card 15 is removed (at which point it returns to the idle state) or a command message is received from the base unit. The objective of this process is to allow the user of the remote control 11 to initiate a transaction with the base unit by keying in data on the remote control (for example a menu selection, a PIN, or some other information). Once the base unit has determined that a valid transaction is to occur, it then transmits a command to the remote control 11 to access data on the Smart Card 15 , such as a cash balance, a pay-per-view movie credit, etc. This series of events are shown in the subsequent portion of the flowchart. At block 9 of FIG. 10, the remote control 11 examines the response command from the base unit. If it is “transaction complete,” the remote control 11 signals the user (block 8 ) and returns to the idle state. If the response command is not “transaction complete,” the remote control 11 then determines if the response is a command to read or to write Smart Card data (block 10 ), what location in the Smart Card's memory is to be accessed, and acts accordingly (blocks 11 and 12 ). If the command was a “write,” the remote control 11 then signals completion to the base unit (block 14 ). After executing the read or write function, the remote control 11 returns to the original state (block 5 ) awaiting further action by the user or base unit. A typical transaction might consist of several of these sequences as, for example, the base unit first reads an account balance from the Smart Card 15 , then interacts with the user to finalize a purchase, and finally debits the account balance and writes the updated value back to the Smart Card memory.
It will also be appreciated from the foregoing descriptions and the flowcharts of FIGS. 6 and 10, since the Smart Card type and function is identified in the data stored on the Card, that a single Smart Card can serve more than one purpose. Furthermore, these are not necessarily limited to only remote control applications. For example, a single Smart Card could contain data to both enable new subscription channels on a cable box or DBS receiver via that base units own Smart Card reader, and data to update the remote control functionality to enable access to that channel.
While the invention has been particularly shown and described with reference to a particular embodiment thereof it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. | A system whereby a user-configurable universal remote control has its device library, that is the code data needed to operate various electronics devices, supplied separately from a releasable readable media storage device, such as a Smart Card. The universal remote control is built with a reader slot into which the customer can insert separately purchased Smart Cards to configure the remote control for exactly those electronic devices he/she wishes to control.
A signal transmitting system, such as for example a cable television operator, which provides services to a number of individual receiver sets, and wherein the sets each include an associated remote control unit, the method of controlling the functions and operation of each set with relation to said system by utilizing a Smart Card which cooperates with the remote control unit to selectively control, enable and disable the functions, options and/or equipment of the individual subscriber. | 7 |
BACKGROUND OF THE INVENTION
In digital computing apparatus and related equipment it is often desirable, for maintenance purposes, to be able to manually enter a binary number pattern into a register and to have an indication of the state of each stage of the register from a location which may be remote from the register in question. For example, in many computing systems, the operator's console or the maintenance unit may be located several feet from the central processor unit (CPU) and for convenience, it is desirable to be able to enter a binary data word or an address into a register in the CPU from the remote console. In the past this has been accomplished by having a push-button switch and an associated indicator lamp connected to each stage of the CPU's register by wires such that when the push-button switch is operated, the binary state of the register stage can be changed and a lamp illuminated or extinguished to indicate the condition of the stage.
Problems have arisen in such prior art arrangements because of the inherent contact bounce or vibration present in most all mechanically operated switches which are commercially available at a reasonable price. With these switches, each operation produces a series of makes and breaks rather than a single make or break due to contact bounce. As such, the register stage to which it is connected may be toggled an indeterminate number of times and end up in a state different from that which was intended by the operator.
Prior art solutions to the contact bounce problem have involved the use of delay circuits triggered by the first pulse of a series of noise pulses which disable the logic network for a period sufficient to enable the noise to subside. Exemplary of this approach is the Morgan et al U.S. Pat. No. 3,795,823 and the McIntosh U.S. Pat. No. 3,673,434. Another proposed solution as set forth in the Brahan U.S. Pat. No. 3,381,143 involves the use of a set-reset type flip-flop interposed between the switch contacts and the output logic circuit such that when the mechanical switch is repositioned, the flip-flop switches state, but successive makes and breaks caused by bounce do not reverse the state of the flip-flop and therefore do not affect the voltage appearing at the output of the flip-flop.
The present invention is considered to be an improvement over that disclosed in the aforementioned Brahan patent in that an inexpensive double-pole double-throw push-button switch and indicator assembly can be made to operate as a toggle switch having a debounce feature, the power supply for the indicator being the same as that for the toggle and debounce circuitry.
In the apparatus of the present invention a pair of transition edge-triggered integrated circuit flip-flops are interconnected with each other and with the push-button switch and indicator lamp so that a first depression of the push-button switch will cause the state of one of the flip-flops to switch and operate the indicator and a second depression of the switch will cause the flip-flop to revert to its prior state and extinguish the indicator. The other flip-flop prevents noise produced by contact bounce from affecting the state of said one flip-flop.
OBJECTS
It is accordingly an object of the present invention to provide an improved toggle switch and indicator assembly for use in electronic digital applications.
Another object of the invention is to provide a manual push-button type toggle switch and indicator assembly which can be used in electronic digital equipment without introducing erroneous operation because of contact bounce.
Still another object of this invention is to provide an inexpensive manually operable toggle switch which produces a noise free output even when the contacts of the push-button switch are subject to bounce upon the closing thereof.
These and other objects and advantages of the invention will become apparent to those of ordinary skill in the art upon the reading of the following detailed description in light of the accompanying drawing in which is illustrated an electrical schematic diagram of the preferred embodiment.
DETAILED DESCRIPTION
Referring to the FIGURE, there is shown enclosed by the broken line box 10 a double-pole double-throw push-button type switch 12 and an associated indicator lamp 14 which are commercially available as a self-contained unit in various forms. The poles 16 and 18 of push-button switch 12 are each connected to a point of reference potential such as ground 20.
The self-contained push-button switch and indicator assembly 10 may be located on an operator's console and connected by conductors 22, 24 and 26 to the circuits to be operated which may be somewhat remote from the operator's console. Hence, as will be more fully explained hereinbelow, an operator sitting at the console may enter a bit of information into the remotely located digital apparatus and obtain an indication of the resulting state of that remote circuit.
Continuing with the description of the interconnection of the various components forming the preferred embodiment, a pole 28 of the push-button switch 12 is connected by way of conductor 22 to the Clear input terminal of an integrated circuit edge-triggered flip-flop 30. This Clear input terminal is also coupled through a bias resistor 32 to a source of positive potential such as, for example, a direct current potential of +5 volts. In a similar fashion, the pole 34 of switch 12 is connected by way of a conductor 24 to the Set terminal of the edge-triggered flip-flop 30 and this Set terminal is also coupled through a bias resistor 36 to the same source of DC potential. Thus, when the push-button switch 12 is in a first position connecting poles 18 and 28 together, the "Pre-Clear" input terminal (C) of flip-flop 30 will be held at ground potential whereas the Pre-Set terminal (S) will be at approximately +5 volts. When the push-button switch 12 is operated to bridge poles 16 and 34, the Set terminal (S) will be connected to ground 20 and the "Pre-Clear" terminal (C) will be at +5 volts.
The true output terminal (Q) of the flip-flop 30 is connected by conductor 38 to the Enable input terminal (E) of a second edge-triggered or D-type flip-flop 40. The indicator lamp 14 has a first terminal thereof connected to the positive source of DC potential (+5 volts) and its other terminal connected through conductor 26 and conductor 42 to the Data input terminal (D) of the edge-triggered flip-flop 40. The complement output (Q) of the edge-triggered flip-flop 40 is connected by means of a conductor 44 back to its Data input terminal (D).
Now that the details of the construction of the preferred embodiment have been set forth, consideration will next be given to its mode of operation.
OPERATION
The edge-triggered flip-flops 30 and 40 may be the Type SN 7474 integrated circuit flip-flops manufactured and sold by the Texas Instruments Corporation of Dallas, Texas and, as such, when the Pre-Clear signal assumes a low binary state, the flip-flop 40 is switched to its cleared state in which the Q output terminal is clamped at approximately +5 volts. As such, no current flows through the indicator 14 and it is therefore off. If a low signal is now applied to the Pre-Set terminal, S, of flip-flop 40 the flip-flop will be switched to its Set state in which the Q output terminal is high (+5 volts) and the Q output terminal will be at ground. A current will therefore flow through the indicator 14 causing it to be illuminated.
When the push-button 12 is in its normally closed position so as to bridge the poles 18 and 28, a constant ground will be applied to the Clear input terminal of the debounce flip-flop 30. As the push-button switch is pushed towards its normally open position, this constant Clear signal is removed from the flip-flop 30 and a ground signal is applied to the Set input terminal, S, of the flip-flop 30 as the push-button 12 initially makes contact between the poles 16 and 34. This ground signal applied to the terminal, S, causes the debounce flip-flop 30 to set. As the flip-flop 30 sets, a positive transition signal appears on conductor 38 and is applied to the Enable input terminal, E, of the edge-triggered flip-flop 40. This transition on the E input of flip-flop 40 causes it to become set because at this time the Data input terminal, D, is high due to the fact that the flip-flop 40 had been pre-cleared. The indicator therefore becomes illuminated and the spring biased push-button switch 12 returns to its normally closed position as the operator removes his finger therefrom.
When the switch is again depressed, the debounce flip-flop 30 operates in the manner previously described to produce a positive transition on its output terminal, Q. However, since at this time the toggle flip-flop 40 is set, its D input is low. When this positive transition occurs on the E input of flip-flop 40, flip-flop 40 will be cleared and the indicator will go off.
Since the debounce flip-flop 30 responds only to the initial transition occurring when ground is connected to either the Clear or the Set terminal, repeated making and breaking of the contacts 16 - 34 or 18 - 28 caused by contact bounce will have no affect on the state of the flip-flop 30.
Thus it can be seen that the present invention provides a way of utilizing a momentary action push-button switch to act as a toggle switch having an indication of the on-off condition of that switch which ensures that no noise spikes will appear on the output line therefrom, even when the push-button switch is subject to contact bounce. Furthermore, only one DC voltage need be made available to operate the switch and its associated indicator. The toggle flip-flop 40, being a Type D flip-flop, can be pre-cleared or pre-set from an outside source (not shown) so as to predetermine the state of the toggle flip-flop 40 to either illuminate the light 14 or extinguish it.
It is to be understood that although the invention has been specifically described in conjunction with a particular embodiment, that various modifications may readily be made without departing from the spirit of the invention. | A toggle switch indicator circuit for use with digital logic circuits which may be manually set and cleared by means of a manually operated push-button switch and which incorporates a debounce network and an indicator for displaying the state of the toggle switch at a remote point. | 7 |
RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 10/142,807, filed on May 9, 2002, now U.S. Pat. No. 7,082,736 entitled “PROCESS FOR RETROFITTING AN EXISTING BUS WINDOW HAVING RUBBER SEALS WITH METAL MEMBERS THAT DEFINE A RETENTION SPACE FOR A SACRIFICIAL MEMBER,” which is a continuation in part of U.S. patent application Ser. No. 10/057,617, filed Jan. 23, 2002 entitled “Quick Release Sacrificial Shield for Window Assembly” now U.S. Pat. No. 6,688,044, issued Feb. 10, 2004, which was a continuation of U.S. patent application Ser. No. 09/395,692 filed Sep. 13, 1999, entitled “Quick Release Sacrificial Shield For Window Assembly” now U.S. Pat. No. 6,408,574, issued Jun. 25, 2002, which was a continuation-in-part of U.S. patent application Ser. No. 09/186,513, filed Nov. 4, 1998, entitled “Quick Release Sacrificial Shield For Window Assembly” now U.S. Pat. No. 6,205,723, issued Mar. 27, 2001. This application also claims the benefit of U.S. Provisional Application No. 60/290,136, filed on May 9, 2001, entitled “PROCESS FOR RETROFITTING AN EXISTING BUS WINDOW HAVING RUBBER SEALS WITH METAL MEMBERS THAT DEFINE A RETENTION SPACE FOR A SACRIFICIAL MEMBER.”
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to windows for mass transit vehicles and, in particular, concerns an apparatus and method for reconfiguring bus windows so as to replace rubber retention members with metal retention members that define a space to receive a sacrificial layer.
2. Description of the Related Art
Mass transit vehicles, for example buses and trains and the like, typically have a plurality of windows positioned adjacent the seats of the mass transit vehicles. One difficulty that mass transit vehicle operators experience is that passengers sitting inside the mass transit vehicle will often use sharp objects to scratch the glazing of the window thereby damaging the appearance of the window. Over time, mass transit vehicles, particularly those used in large urban areas, can have windows that are significantly obscured with scratched glazings that may contain offensive comments and slogans. Replacement of the glazing can be a particularly expensive proposition given the difficulty of removing the glazing from the window and the expense of purchasing a replacement sheet of glazing that is specifically sized to meet the contours of particular window opening of the mass transit vehicle.
To address this particular need, sacrificial layers are often positioned at the inner surface of the glazing wherein the sacrificial layer is interposed between the rider of the mass transit vehicle and the inner surface of the glazing. Typically, the sacrificial layer is a layer of inexpensive acrylic or plastic that can be more easily removed and replaced than the underlying glazing. Hence, users who would otherwise attempt to damage the glazing end up damaging the sacrificial layer that can then be easily replaced.
One common mechanism for retaining the sacrificial layer is to position a rubber gasket in the window frame so as to extend around the periphery of the opening of the window frame. This gasket can then define a space into which the edges of the sacrificial layer can be positioned so as to retain the sacrificial layer adjacent the glazing. Such a gasket also retains the glazing of the window within the frame. Thus, when the sacrificial layer and/or the glazing of the window is to be replaced, the rubber gasket needs to be removed from the frame. After the sacrificial layer and/or the glazing of the window is replaced, the gasket, frequently a new set, is repositioned in the window frame.
One difficulty with the use of such a rubber retainer is that replacement of the rubber can be a very time consuming and costly endeavor. In particular, the rubber retainer must be removed from the window frame, and over time such rubber retainer can no longer be used. Consequently, a new rubber retainer must then be installed into the window frame to replace the damaged rubber retainer. Installation of such a rubber retainer is often a very difficult and time consuming process which is even more exacerbated by the fact that most mass transit vehicles have multiple windows that require multiple retainers.
Hence, there is an ongoing need for window protectors and, in particular, sacrificial window protectors that can be more easily replaced at a reduced cost. To this end, there is a need for a reusable retainer for use in conjunction with the sacrificial layers.
SUMMARY OF THE INVENTION
The aforementioned needs are satisfied by a method of retrofitting an existing window in a mass transit vehicle with a replacement sacrificial member retention assembly. The method comprises extracting a rubber gasket from a recess formed in the frame of the window so that the rubber gasket no longer retains the sacrificial member adjacent a first side of a glazing of the window. The rubber gasket also no longer retains the glazing in the frame. The method further comprises sizing a rigid retainer such that the rigid retainer can be positioned in the recess. The method further comprises positioning a plurality of rigid retainers into the recess in the frame such that the rigid retainers are able to retain the sacrificial member adjacent the first side of the glazing. The rigid retainers are also able to retain the glazing in the frame. The method further comprises positioning a sacrificial member adjacent the first side of the glazing so as to be retained by the rigid retainers.
One implementation of the method further comprises, prior to positioning a plurality of rigid retainers, positioning a replacement glazing in the frame. The rigid retainer preferably comprises a first leg sized to fit into the recess in the frame, and a second leg that defines a space sized to receive the sacrificial member such that the sacrificial member is secured adjacent the first side of the glazing. The second leg retains the glazing in the frame by engaging the portion of the first side of the glazing. The space defined by the second leg is dimensioned such that the edges of the sacrificial member slide within the spaces of the rigid retainers positioned at opposite sides of the frame so as to facilitate removal and positioning of the sacrificial member. In one embodiment, the second leg is further adapted to permit a fastener to extend into the space so as to inhibit sliding of the sacrificial member.
The rigid retainer positioned in the recess in the frame remains in place when the sacrificial member is replaced. The rigid retainer is formed from a resilient material to permit repeated use as sacrificial member is replaced repeatedly, and in one embodiment the rigid retainer is formed from a metal. Such rigid retainer is used to retrofit a mass transit vehicle such as a bus.
Another aspect of the invention relates to a method of replacing a sacrificial member of a window in a mass transit vehicle. The method comprises removing a rubber gasket from a recess formed in a frame of the window so that the rubber gasket no longer retains the sacrificial member adjacent a first side of a glazing of the window. The method further comprises removing the existing sacrificial member from the first side of the glazing. The method further comprises substituting the rubber gasket with at least one rigid retainer that is dimensioned to fit into the recess in the frame of the window and retain the sacrificial member adjacent the first side of the glazing. The method further comprises installing a new sacrificial member such that the at least one rigid retainer retains the new sacrificial member adjacent the first side of the glazing.
The rigid retainer preferably comprises a first leg sized to fit into the recess in the frame and a second leg that defines a spaced sized to receive the sacrificial member such that the sacrificial member is secured adjacent the first side of the glazing. The space defined by the second leg is dimensioned such that the edges of the sacrificial member slides within the spaces of the plurality of rigid retainers positioned at opposite sides of the frame.
Installing the new sacrificial member comprises sliding the upper edge of the sacrificial member into the space of the at least one rigid retainer positioned at the top of the frame so as to facilitate positioning of the lower edge of the sacrificial member into the space of the at least one rigid retainer positioned at the bottom of the frame. In one embodiment the second leg is further adapted to permit a fastener to extend into the space so as to inhibit sliding of the sacrificial member.
The rigid retainer is formed from a resilient material to permit repeated use as sacrificial member is subsequently replaced repeatedly, and in one embodiment the rigid retainer is formed from a metal. Such rigid retainer is used to replace the sacrificial member of the window in mass transit vehicles such as a bus.
Yet another aspect of the invention relates to a method of replacing a glazing of a window in a mass transit vehicle. The method comprises removing a rubber gasket from a recess formed in a frame of the window so that the rubber gasket no longer retains the glazing in the frame. The method further comprises removing the glazing from the frame, and installing a new glazing in the frame. The method further comprises substituting the rubber gasket with at least one rigid retainer that is dimensioned to fit into the recess formed in the frame and retain the glazing in the frame.
In one implementation, the method further comprises, after substituting the rubber gasket, installing a sacrificial member adjacent the glazing such that the sacrificial member is also retained by the at least one rigid retainer. In one embodiment, the rigid retainer comprises a first leg sized to fit into the recess in the frame and a second leg adapted to retain the glazing in the frame. The rigid retainer is formed from a resilient material to permit repeated use as glazing is subsequently replaced repeatedly. In one embodiment, the rigid retainer is formed from a metal, and such rigid retainer is used in mass transit vehicles such as a bus.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a typical bus that exemplifies a common mass transit vehicle;
FIG. 2A illustrates a typical window assembly found on mass transit vehicles such as the bus of FIG. 1 ;
FIG. 2B illustrates a cross sectional view of a frame of the window assembly showing how a sacrificial member is traditionally mounted adjacent a glazing;
FIG. 3 illustrates a manner in which the sacrificial member is traditionally replaced;
FIG. 4 illustrates a cross sectional view of the frame showing retrofitting of the window assembly with a retention member that retains the sacrificial member and the glazing;
FIG. 5A illustrates a cross sectional view of the bottom portion of the frame showing the retrofitted window assembly;
FIG. 5B illustrates a cross sectional view of the top portion of the frame showing a space defined by the retention member dimensioned so as to permit improved replacement of the sacrificial member; and
FIG. 6 illustrates one embodiment of the retrofitted window assembly with a plurality of retention members positioned at selected locations.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will now be made to the drawings wherein like numerals refer to like parts throughout. FIG. 1 illustrates a bus 101 that exemplifies a common mass transit vehicle. The bus 101 comprises a plurality of windows 100 positioned at selected locations on side panels 103 . Each window 100 comprises a glazing 104 mounted on a frame 102 . It is common for the window 100 to further comprise a sacrificial member 106 that protects the glazing 104 .
FIG. 2A illustrates an isolated view of one typical window 100 that might be found on mass transit vehicles such as the bus 101 of FIG. 1 . The window 100 comprises the glazing 104 mounted on the frame 102 . The window 100 may further comprise a sacrificial member 106 that forms a layer adjacent to the glazing 104 , so as to provide a replaceable protective barrier between the glazing 104 and occupants of the vehicle. As is known in the art, windows in mass transit vehicles are subjected usual wear and tear as well as acts of intentional vandalism. The replaceable sacrificial member 106 protects the more costly glazing 104 from such mistreatments. Traditionally, the sacrificial member 106 is secured to the window 100 by a gasket 110 in a manner described below. One type of the costly glazing 104 is approximately ¼″ thick, and one type of the sacrificial member 106 is less than ⅛″ thick.
FIG. 2B illustrates a cross sectional side view of the frame 102 , showing the glazing 104 mounted in the frame 102 with an external seal member 112 interposed therebetween. The seal member 112 seals out the exterior of the vehicle from the interior of the vehicle in a manner well known in the art.
The sacrificial member 106 is positioned in a layer adjacent a first side 108 of the glazing 104 , and is secured in place by the gasket 110 that is pressed into a recess 114 defined by the frame 102 . The gasket 110 is selected so as to permit it to securely hold the sacrificial member 106 in place. The gasket 110 may be secured in place either by frictional fit, or by an adhesive. The gasket 110 also retains the glazing 104 in the frame 102 adjacent the seal member 112 .
FIG. 3 illustrates the traditional method of replacing the sacrificial member 106 , wherein the gasket 110 is removed from the frame 102 so as to permit the sacrificial member 106 to be removed. As is well known in the art, once a gasket is removed from its fixed configuration of extended time, it loses some of its usefulness. Thus after several use over time, the gasket 110 may become brittle and cracked, rendering it unsuitable for further use. As a result, the gasket 110 typically needs to be replaced regularly, thus adding to the cost of time and material associated with the procedure. Since the gasket 110 also retains the glazing 104 in the frame 102 , the gasket 110 needs to be removed when the glazing 104 is replaced. This further increases the cost of window maintenance when such gaskets are used. Aside from the material cost of the gasket, re-installing the gasket is labor-intensive, thus further adding to the cost of window maintenance.
FIGS. 4 , 5 A and 5 B illustrate a process for retrofitting the window 100 so as to remove its dependence on the gasket 110 to secure the sacrificial member 106 and the glazing 104 in place. After the gasket 110 is removed from the frame 102 , as described above in reference to FIG. 3 , a retainer member 120 is inserted into the recess 114 that was previously occupied by the gasket 110 . As shown in a cross sectional view in FIG. 4 , one embodiment of the retainer member 120 comprises a first leg 122 and a second leg 124 . The first leg 122 is sized to fit into the recess 114 that previously received the rubber gasket 110 , and the second leg 124 is spaced outward from the first leg 122 so as to define a space 132 into which a sacrificial member 106 can be positioned adjacent the first side 108 of the glazing 104 .
In one embodiment, the first leg 122 has a rounded end 126 so as to facilitate easier insertion into the recess 114 . The first leg 122 further comprises a plurality of serrations 130 that helps to secure the first leg 122 in the recess 114 . In one embodiment, the retainer member 120 further defines various openings 134 that can receive additional seals and the like.
Preferably, the retrofitting of the window 100 is performed when the sacrificial member 106 is replaced. It will be appreciated, however, that the retrofitting of the window 100 can be performed at any time without departing from the spirit of the invention.
FIG. 5A illustrates a cross sectional view of a retrofitted window 100 , wherein the retainer member 120 has replaced the gasket 110 described above in reference to FIGS. 2 and 3 . The first leg 122 engages the frame 102 such that the sacrificial member 106 can be received into the space 132 defined by the second leg 124 , and held therein securely adjacent the first side 108 of the glazing 104 .
As shown in FIG. 5A , the sacrificial member 106 is retained in place adjacent the first side 108 of the glazing 104 by one embodiment of a first seal 146 mounted in the openings 134 defined by the second leg 124 . In particular, the first seal 146 engages the portion of the sacrificial member 106 and pushes it against the first side 108 of the glazing 104 . Furthermore, the cross section of the first seal 146 defines a wedge whose tip engages the first side 108 of the glazing 104 , thus retaining the glazing 104 securely adjacent the seal member 112 . A portion of the wedge defined by the first seal 146 engages the edge of the sacrificial member 106 and inhibits the sacrificial member 106 from sliding beyond the first seal 146 . In one embodiment, the first seal 146 is made from resilient rubber or hard vinyl so as to provide sealing and retaining properties in a reusable manner.
FIG. 5B illustrates another retainer member 140 that is similar to the retainer 120 described above. The retainer member 140 comprises a first leg 142 and a second leg 144 , wherein the second leg 144 is adapted to permit a fastener 152 to extend into a space 150 defined by the second leg 144 . The retainer member 140 is positioned on the opposite side from the retainer member 120 in order to permit the sacrificial member 106 to be installed and removed from the window in a manner similar to the process disclosed in a co-pending Provisional Application by Farrar titled “Sacrificial shield for window assembly”, Ser. No. 09/820,184, filed on Mar. 27, 2001. The sacrificial member 106 is sized such that when installed, the fastener 152 extending into the space 150 inhibits the sacrificial member 106 from moving while occupying a portion of the space 150 . To remove the sacrificial member 106 , the fastener 152 is retracted from the space 150 so as to permit the sacrificial member 106 to slide into the rest of the space 150 , thus freeing the other edge of the sacrificial member 106 from the space 132 described above in reference to FIG. 5A .
FIG. 5B further illustrates one embodiment of a second seal 148 mounted in openings 160 defined by the second leg 144 . In particular, the second seal 148 engages the portion of the sacrificial member 106 and pushes it against the first side 108 of the glazing 104 . Furthermore, the cross section of the second seal 148 defines a wedge whose tip engages the first side 108 of the glazing 104 , thus retaining the glazing 104 securely adjacent the seal member 112 . It will be appreciated that the process of retrofitting the portion of the window with the retainer member 140 is substantially similar to the process described above in reference to the retainer member 120 . It will further be appreciated that other procedures (than that disclosed in Provisional application Ser. No. 09/820,184) may be employed to install and remove the sacrificial member 106 from the window 100 without departing from the spirit of the invention.
FIG. 6 illustrates an exemplary embodiment of the retrofitted window 100 comprising the retainer members 120 being positioned on the opposite sides of the retainer members 140 so as to permit installation and removal of the sacrificial member 106 as described above. In another embodiment of the retrofitted window 100 , the retainer member 140 of FIG. 5B is substantially same as the retainer member 120 of FIGS. 4 and 5A . The window is retrofitted such that the retainer member positioned at the bottom of the window is fitted with the first seal 146 as described above in reference to FIG. 5A , and the retainer members positioned at the top and sides of the window are fitted with the second seal 148 described above in reference to FIG. 5B .
It will be appreciated that the retrofitted window 100 permits subsequent changes of the sacrificial members 106 to be performed in an easier manner. Furthermore, the retrofitted window 100 permits replacing of the glazing itself when necessary (such as when the glazing is damaged) in an improved manner described above. In one embodiment, the retainer members 120 , 140 are formed from a resilient material such as plastic or vinyl so as to permit repeated use, thus providing cost savings by not discarding the traditional gaskets described above.
Although the foregoing description of the preferred embodiment described and pointed out the fundamental features of the invention, it will be understood that various omissions, substitutions and changes in the form of the detail of the apparatus and method as illustrated, as well as the use thereof, may be made by those skilled in the art, without departing from the spirit of the present invention. | A process of retrofitting an existing window that uses a gasket to secure a sacrificial member and a glazing. The sacrificial member forms a replaceable protective barrier between the glazing and occupants of a vehicle such as a bus. The gasket is traditionally used to secure the sacrificial member and the glazing to the window. Over time, after several removal and re-installations during replacement of the sacrificial member or the glazing, the gasket typically becomes unfit for subsequent use. The gasket is replaced with a rigid retainer member that fits into an existing recess that receives the gasket. The retainer member secures the sacrificial member and the glazing to the window so as to permit repeated changes of the sacrificial member without removal of the retainer member. | 4 |
This application is a continuation-in-part Of U.S. patent application Ser. No. 09/089,469 filed on Jun. 2, 1998 that issued as U.S. Pat. No. 6,154,892 on Dec. 5, 2000.
TECHNICAL FIELD
The invention relates to a seat and lid assembly for a toilet, and more particularly to such a seat and lid compromising injection molded, reinforced plastic inserts injection over-molded with a chemically compatible material which provides the desired outer surface characteristics of the seat and lid.
BACKGROUND ART
The invention is directed to the improvement of the feel and comfort of a toilet seat and lid, and to the provision of a comfortable, warm, non-slip seating surface. This is accomplished by utilizing modern thermoplastic material and high-pressure injection molding techniques. While not intending to be so limited, the invention will be described in its application to a toilet seat and lid. It will be understood that the basic teachings of the present invention can be applied to toilet seats without lids and other types of seats.
Prior art workers have devised many types of toilet seats and lids to improve the comfort, look and convenience thereof Heretofore toilet seats and lids have been constructed from rigid materials such as wood or plastic, or made from a solid core upholstered in foam padding and/or a vinyl covering. Typical rigid plastic or wood seats are relatively cold to the touch and slippery. Upholstered seats and lids, with or without padding, are not particularly durable and are susceptible to cuts and tears. Additionally some people find the feel of padded vinyl seats and lids to be undesirable. Prior art workers have molded a material over another material in an attempt to hide imperfections in a thick part but still produce a hard rigid seat that does not address the issues of comfort and non slip characteristics. Prior art workers have also attempted to produce a padded, resilient-type seat using complicated and costly molding methods employing catalyzed materials such as urethane. Molding a seat by using catalyzed low pressure materials requires time-consuming mixing and pouring, resulting in less than satisfactory results and a costly product.
The present invention is based upon the discovery that a seat and lid assembly comprising inserts of reinforced thermoplastic material, with over-molded thermoplastic material which determines the characteristics of the outer surface of the seat and lid, can overcome the above noted problems. There are six Shore scales that are used to measure the hardness of synthetic materials. They are as follows: Shore A, Shore B, Shore C, Shore D, Shore DO and Shore OO. All of the scales range from 0-100. The most commonly used scales are Shore A and Shore D. There is no direct conversion between the different scales. An example of an approximate comparison would be (Shore A 50=Shore B 30-35=Shore C 20=Shore D 10-15). Another example of approximate comparison would be (Shore A 100=Shore B 85=Shore C 65=Shore D 45). The preferred polypropylene material used for the insert has a hardness of approximately Shore D 70. When a thermoplastic elastomeric material with a Shore A durometer of 90 or below is used as the over-mold material, the seat and lid are provided with a soft, comfortable, durable surface which will not tear and which have non-slip characteristics, which, nevertheless, allows reasonable mobility while using the seat. The thermoplastic elastomeric material should not have a durometer hardness greater than Shore D50. Some synthetic materials have a durometer hardness that would be measured on the Shore A scale. Harder synthetic materials would be measured on the Shore D scale. The elastomer provides a completely different and arguably superior feel as compared to conventional seats and padded seats. The seat of the present invention is not padded and does not deform when sat upon. The surface also provides an aesthetically pleasing finish which is easily cleaned and is available in many colors.
It is an object of the present invention to provide an injection molded toilet seat and lid which are soft to the touch and relatively warm and non-slip as compared to a conventional hard seat and lid.
It is an object of the present invention to provide a toilet seat and lid with the above features which are both strong and durable.
It is an object of the present invention to provide a toilet seat and lid with the above features which are easy to clean.
It is an object of the present invention to provide a more comfortable and non-slip toilet seat and lid assembly, than is achievable with existing designs and conventional construction techniques.
It is an object of the present invention to provide a seat and lid with antimicrobial qualities.
Finally, it is an object of the invention to provide a soft feeling injection molded toilet seat shaped to fit the user comfortably.
DISCLOSURE OF THE INVENTION
According to the invention there is provided a strong, durable, comfortable toilet seat and lid assembly which is non-slip and easy to clean. The assembly comprises rigid inserts molded of a reinforced thermoplastic material. The inserts are over-molded with a thermoplastic material which provides them with the desired surface characteristics.
The inserts are precisely dimensioned so that their areas to be over-molded are smaller than the finished seat. The inserts are designed to give maximum strength to the seat and lid and are shaped to promote the flow of the over-mold material to minimize flowjoint or flow weld problems, to be described hereinafter. Each insert is designed to minimize shrinking, swelling or distortion thereof and, to this end, can be provided with strategically located ribs and appropriate cored areas.
When the thermoplastic material of the inserts and the over-mold material elastomer are both of the same chemical base, the over-mold will bond both mechanically and chemically with the inserts and will provide the seat and lid with a soft, comfortable, non-slip surface. The surface may be smooth or textured to enhance the feel and appearance of the seat.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an inside elevational view of the lid insert of the present invention.
FIG. 2 is a top plan view of a seat insert of the present invention.
FIG. 3 is an inside elevational view of an over-molded lid of the present invention.
FIG. 4 is a fragmentary cross-sectional view taken along section line 4 — 4 of FIG. 3 .
FIG. 5 is a top plan view of an over-molded seat of the present invention.
FIG. 6 is a fragmentary cross-sectional view taken along section line 6 — 6 of FIG. 5 .
FIG. 7 is a side elevational view of the lid and seat of FIGS. 3 and 5.
FIG. 8 is an elevational view of the upper surface of the lid of FIG. 7 and the bottom surface of the seat of FIG. 7 .
FIG. 9 is a cross-sectional view taken along section line 9 — 9 of FIG. 8 .
FIG. 10 is a cross-sectional view taken along section line 10 — 10 of FIG. 8 .
FIG. 11 is a perspective view of the over-molded seat of the present invention together with the hinge elements by which it is hingedly attached to the toilet bowl.
FIG. 12 is an exploded view illustrating the outside surface of the lid of the present invention and the bottom surface of the seat of the present invention.
FIG. 13 is a top plan view of a seat of the present invention provided with areas or bands of texture.
FIG. 14 is a top plan view of the lid of the present invention provided with areas or bands of texture.
FIG. 15 is a top plan view of a lid having a sculpture formed by the over-molding.
FIG. 16 is an exploded view of a lid and seat of the present invention provided with hinge elements which are embedded in the inserts thereof.
FIG. 17 is a bottom plan view of a seat of the present invention provided with a groove to receive a heating element. FIG. 18 is a cross-sectional view of a seat of the present invention provided with a groove and heating element therein covered by the over-mold material.
FIG. 18 is a cross-sectional view of a seat of the present invention provided with a groove and heating element therein covered by the over-mold material.
DETAILED DESCRIPTION OF THE INVENTION
It will be understood by one skilled in the art that, for each type or model of seat and lid to which the present invention is to applied, the finished seat and lid, inserts and the molds must be appropriately designed in accordance with the teaching of the present invention.
The exemplary seat and lid are each made of two major parts, (an insert and an over-mold), in two steps. In some embodiments additional parts may be used such as hinges imbedded on or molded as part of the inserts, as will be described hereinafter. In the exemplary embodiment, the first step is the injection molding of the strong substantially rigid, lightweight seat inserts. The inserts are best shown in FIGS. 1 and 2, and are generally indicated at 1 a and 1 b . The inserts 1 a and 1 b constitute substantially the bulk of the finished seat and lid and serve as the skeleton of the over-molded seat 2 b and 2 a of FIGS. 3 and 5. The seat portion insert 1 b of FIG. 2 comprises a generally oval structure forming the shape of the seat, and is dimensioned to fit the particular toilet for which it is designed. The seat may have any appropriate shape including the well-known “C” shape, open-front configuration. The lid insert 1 a is generally shaped in an oval to approximate the shape of the finished lid 2 a . The rearward portions of the lid insert 1 a and the seat insert 1 b have either hinges 3 and 3 a molded as part of the inserts as shown in FIGS. 1 and 2, or hinges imbedded or otherwise appropriately attached to the inserts as shown in FIG. 16 .
The inside surface of the lid insert 1 a is provided with four integral stand-offs constituting a one-piece part of insert 1 a and indicated at 1 c , 1 d , 1 e , and 1 f . In a similar fashion, the bottom surface of the seat insert 1 b is provided with four integral stand-offs constituting a one-piece part of insert 1 b and indicated at 1 g , 1 h , 1 i and 1 j.
Inserts 1 a and 1 b are preferably molded of a strong, reinforced, synthetic material. Any appropriate synthetic material can be used as long as it is chemically compatible with the over-molded material. The synthetic material of the inserts may include a reinforcing filler material. Some examples of a reinforcing filler material are: 1) a fiberglass reinforced, olefin base, thermoplastic material, 2) a fiberglass reinforced polypropylene, 3) a fiberglass reinforced polypropylene containing from about 1% to about 2% of a foaming agent. When the preferred thermoplastic elastomer TPE) over-mold is used as is described hereinafter, an olefin base thermoplastic material is necessary for the insert because, under these circumstances, the over-mold material will chemically bond with the insert material. When the injection molded seat insert comprises an olefin thermoplastic, the over-mold layer may comprise an olefin base thermoplastic elastomer chemically bonded to the injection molded seat insert. When the injection molded seat insert comprises a fiberglass reinforced polypropylene, the over-mold layer may comprise an olefin base thermoplastic elastomer chemically bonded to the injection molded seat insert. Excellent results have been achieved, for example, when specific formulations of polypropylene are used as the base reinforcing insert. The preferred high Crystalline, Homo-polymer polypropylene provides excellent adhesion to compatible olefin elastomers as well as a high resistance to abnormal sinks and flow lines. This material, once cured, has a great scratch resistance and a higher flexural modulus than co-polymer polypropylene. An example of such material is manufactured by Huntsman Corp of Salt Lake City, Utah and is identified as product #HOMPP-P4C6Z052.
The reinforced synthetic material can also be combined with an endothermic foaming agent. The foaming agent enables the molding of thick, lightweight portions of the insert without visible “sink” areas, gross warping, or the like. In addition, the foaming agent helps minimize or eliminate “joint” and “weld” problems. Welds, for example, are created when portions of molten plastic, traveling in different directions, meet in the mold and solidify. The insert mold must be designed in such a way to overcome this problem so that the weight of a person sitting or standing on the seat will not cause a failure. A preferred way to overcome or minimize flow joints or flow welds is to introduce the material into the mold from one source through a single gate, when possible. On the other hand, in accordance with conventional molding techniques, the sheer size of the seat would dictate the provision of multiple sources of mold material and multiple gates to guarantee complete fill. Multiple sources and gates, however, potentially cause welds and joints. In the insert embodiments illustrated in FIGS. 1 and 2, the joint and weld problems were overcome by using the above noted endothermic foaming agent which, when activated, becomes solvent-like, thereby lowering the polymer viscosity during the injection molding process for the inserts 1 and 1 a . Because of the reduced melt viscosity, molds can be made for the lid and seat inserts, each having a single gate resulting in the production of lid and seat inserts free of numerous polymer welds. With other seat designs and configurations multiple gates may be desired or required.
The foaming agent also enhances the inserts by creating essentially a structural “honeycomb” within the inserts themselves. Excellent results have been achieved with a foaming agent sold by Reedy International of Keyport, N.J., under the trademark SAFOAM and the designation PE-50. The foaming agent constitutes from 1% to 2% of the synthetic material-foaming agent combination.
The inserts are designed to give maximum strength to the finished seat and lid assembly. In addition, the inserts may be cored out in critical thick areas to reduce warping, excessive swelling or other deformation of the insert.
As indicated above, each overall insert is precisely dimensioned so that its areas to be over-molded are smaller than the finished seat. The dimensions are chosen to minimize warpage of the insert and to allow for proper over-molding material flow and bonding.
Once inserts 1 a and 1 b are molded, the next step is to mount the inserts in final molds and injection mold (over-mold under heat and pressure) thereon the thermoplastic elastomer. As indicated above, the thermoplastic elastomeric material preferably should be chemically compatible with the material from which the inserts are molded so that a chemical bond occurs between the synthetic material of the insert and the thermoplastic elastomer of the over-mold. Excellent results have been provided, for example with a thermoplastic elastomer provided by Advanced Elastomer Systems of St. Louis, Mo., under the trademark SANTOPRENE.
An antimicrobial additive can be blended with the Santoprene to give the seat surface built-in antimicrobial characteristics. Excellent results have been achieved with an antibacterial additive provided by Morton International of Boston, Mass. under the designation Vinyzene.
The inside elevation view of FIG. 3 illustrates the over-molded lid insert, generally indicated at 2 a . FIG. 5 is a top view of the over-molded seat insert, generally indicated at 2 b . FIG. 4 is a fragmentary transverse cross-sectional view of the over-molded lid 2 a taken along section line 4 — 4 of FIG. 3 . FIG. 6 is a fragmentary cross-sectional view taken along section line 6 — 6 of FIG. 5 . FIG. 7 is a side elevational view and FIG. 8 is a view of the assembled over-molded lid 2 a and over-molded seat 2 b illustrating the top surface of the over-molded lid 2 a.
In these figures, the thermoplastic rubber over-mold is generally indicated at 10 . The rearward most end of the lid and seat inserts are over-molded, with the exception of the hinge contact points as is clearly shown in FIGS. 3, 5 and 10 . Generally, the entire exterior surfaces of inserts 1 a and 1 b are over-molded although on some designs some insert surfaces will be exposed. For example, in the preferred embodiment, ribs 11 a and 11 b , 11 c and 11 d are not over-molded (see FIG. 8 ). In addition, each of the lid stand-offs 1 c , 1 d , 1 e and 1 f and each of the seat stand-offs 1 g , 1 h , 1 i and 1 j has a hole 12 formed in the over-molding material thereon. These are clearly shown in FIGS. 3 and 8. The holes are formed by the molds for the over-molding process which uses the stand-offs of the lid 2 a and 2 b as contact points for the mold elements which support the inserts 1 a and 1 b in the over-mold molds. FIG. 9 is a cross-sectional view taken along section 9 — 9 of FIG. 8 . The section line passes through stand-off 1 g and clearly shows the hole 12 . FIG. 10 clearly shows that the hinge contact points are not over-molded.
Reference is made to FIGS. 10 and 11. These figures show the hinge elements 3 a of seat 2 b . The figures also illustrate an additional hinge element 3 b for each hinge element 3 a by which the seat and lid are affixed to the toilet bowl. Each of the two hinge elements 3 b have a base portion 3 c and an upstanding hinge member 3 d . Each base portion 3 c has a perforation 3 e formed therein enabling it to be bolted to the toilet bowl. The hinge elements 3 b could comprise over-molded elements except for the hinge contact faces. They could also simply comprise metallic or plastic molded members. In FIG. 11 it is clear that the hinge element 3 a of seat 2 b lie just inside hinge elements 3 d . While the lid 2 a and its hinge elements 3 are not shown in FIG. 11, it is evident from FIG. 5 that the lid hinge elements 3 will lie just outside hinge elements 3 d . The hinge elements of each group of three 3 , 3 d , and 3 a have coaxial perforations for the receipt of a hinge pin.
It will be understood that distortion considerations due to shrinkage, warpage, outside forces and the like are unique with respect to each over-molded seat. The inserts 1 a and 1 b are first molded at which point minimal shrinkage or warpage may occur and thereafter the insert components become stabilized.
Next, the over-molding places a new thermoplastic material over the already stabilized inserts creating stresses not found in single stage molded parts, When the over-mold material is applied to the inserts with the appropriate heat and pressure, and then allowed to cool and stabilize, shrinkage of the thermoplastic rubber will tend to warp certain areas of the lid and seat.
Strategically placed ribs 11 a , 11 b , 11 c and 11 e , as shown in FIG. 12, can be used to minimize or eliminate this distortion. Since the thermoplastic material of the insert and the thermoplastic rubber are compatible, the materials will chemically bond under the heat and pressure of the injection molding operation.
Again it is desirable to prevent unsightly weld and joint lines in the over-mold material. In the exemplary embodiment of FIGS. 3 and 5, it is possible to introduce the over-mold material into the mold through a single gate approximately at 17 . The ribs 11 a , 11 b , 11 c , 11 e and 13 a , 13 b and 13 c of FIG. 12, and ribs 14 a , 14 b , 14 c and 14 d of FIG. 2 (which are unique to each seat and lid) are designed and located to minimize the disturbance of the flow of the thermoplastic elastomer. At the same time, the flow path of the elastomer in the mold must be carefully designed to provide the most efficient elastomer-to-insert bonding.
Insert 1 b is also designed to provide a mechanical bond, wherever possible, between the thermoplastic rubber and the insert. In areas where delamination would be most likely to occur, such as at thin fleeting edges of the insert, the insert is configured to cause the thermoplastic rubber to hook thereabout, forming a permanent melt seal. Such permanent melt seals are indicated at 15 in FIG. 6 .
Because of the two-step injection molding process of the present invention, specific rheological analysis was made to ensure compatibility between the two processes and to provide critical data such as linear and transverse shrinkage ratios, as well on the structural strength, shrinkage, and warpage of the seat assembly.
During the injection molding of the insert 1 a , the reinforced synthetic material was introduced into the mold at a point generally indicated in FIG. 1 at 16 . This, of course, created a sprue which had to be removed. During the over-molding process the insert 1 a was supported in the second mold primarily by means on pins entering openings indicated at 12 in FIG. 3 and also the seat supported by the nibs 11 a , 11 b , 11 c , and 11 e . Again, a single gate was used, the gate being located at a point generally indicated at 17 in FIG. 3 . Again a sprue was created and removed.
It is within the scope of the invention to provide selected portions of the surface of the over-molded thermoplastic elastomer with a appearance-enhancing texture. The texture may be of any appropriate and well known type. In FIG. 13 and 14, the upper seating portions of the seat and the entire lid are shown provided with textured areas 18 and 19 , respectively, wherein the surface is of a subtle type which enhances the appearance. At the same time, the textured surface 18 and 19 preferably allow the user adequate mobility while seated and also retained easy cleaning characteristics. It will be understood that textured areas may be applied to the entire seat and lid surface or selectively as desired or not at all. For decorative purposes some seats and lids may also be molded with sculpted surfaces. The sculpted surfaces may be of any appropriate design. In FIG. 15, the top surface of lid 2 a is shown provided with one such sculpted area indicated at 20 .
As stated above, some seats and lids may be made with the hinges molded as part of the insert and some may use separate decorative hinges made of metal or plastic for example. An exemplary metal hinge is illustrated in FIG. 16 at 20 .
When a seat assembly of the present invention is to be provided with metal hinges such as cooperating hinge elements 20 a and 20 b (see FIG. 16 ), the hinge elements are provided with perforated flanges 21 a and 21 b molded into the inserts providing a secure mechanical bond between each hinge element and its respective seat or lid insert. The over-mold may also incorporate parts of the hinge. FIG. 16 illustrates a seat assembly 22 a and 22 b of the present invention provided with separate molded in hinge elements 20 a and 20 b . The hinge elements 20 a and 20 b may be made of metal, rigid plastic, or any other appropriate rigid material.
To further enhance the flexibility in manufacturing specialized seats and take advantage of the unique molding process, FIGS. 17 and 18 show channels 23 that can be incorporated in the reinforced thermoplastic seat inset 1 b to allow for the installation of a low wattage heating element or elements 24 . The insert with the heating element would then be over-molded thereon with the thermoplastic elastomer totally encasing the heating element. Provisions are made on the over-mold to allow the electrical cord to exit the mold during the molding process. On the finished seat the cord would exit the rear of the seat so that it could be plugged it to a convenient electrical outlet.
Modifications may be made in the invention without departing from the spirit of it. For example, the teachings of the present invention are also applicable to toilet seats without lids. | A toilet seat and lid, each comprising a rigid insert injection molded of thermoplastic material. Each insert is then over-molded by injection molding with a thermoplastic elastomeric material which provides the outer surface of the seat and lid. The inserts are dimensioned with respect to their over-molded surfaces to be smaller than the finished seat and lid and are designed to give maximum strength to the seat and lid. Each insert is shaped to promote the flow of the over-mold material and to minimize shrinking, swelling or distortion of the insert. The elastomeric material is preferably chemically compatible with the inserts to allow a chemical as well as a mechanical bond to take place. The over-molded material provides the desired soft, non-slip, warm to the touch outer characteristics of the seat and lid. | 0 |
[0001] This invention was made with U.S. Government support under Agreement No. DE-AR0000186 awarded by the Department of Energy. The U.S. Government may have certain rights under this invention.
TECHNICAL FIELD
[0002] This invention pertains to the formation of nanometer size particles of iron-nickel alloys in which the iron and nickel atoms are arranged in the tetragonal L1 0 crystal structure. Mixtures of iron and nickel atoms are formed in their vapor state and the iron-nickel vapor is cooled very rapidly to form nanometer size particles in which the iron and nickel atoms are organized in the tetragonal L1 0 crystal structure.
BACKGROUND OF THE INVENTION
[0003] There is a continuing need for relatively inexpensive, high performance permanent magnet materials. For example, in the automotive vehicle industry there is a particular need for such permanent magnet materials, having relatively high curie temperatures Tc (>300° C.), in traction motors, generators, and other applications.
[0004] Iron-nickel alloys are believed to offer permanent magnet properties providing they can be formed in the tetragonal L1 0 crystal structure. There is a need to form very small particles of compositions of elemental iron and nickel that may be consolidated into unitary shapes to serve as permanent magnets. Iron (atomic number 26) and nickel (atomic number 28) are similarly-sized transition element atoms. A molten mixture of elemental iron and nickel may be solidified as a face-centered cubic (fcc) crystal structure with the iron and nickel atoms in a disordered arrangement. But the disordered fcc crystal structure of iron and nickel atoms does not provide the magnetic anisotropy that is necessary for permanent magnet properties. There is a need for a method by which iron and nickel atoms may be formed into nanometer size particles of iron-nickel alloys in which the iron and nickel atoms are arranged in layers such that the resulting crystals are not cubic, but tetragonal and in the L1 0 -type AuCu 1 crystal structure to provide magnetic anisotropy.
SUMMARY OF THE INVENTION
[0005] This invention provides a method for forming nanometer size particles of iron and nickel having a L1 0 -type tetragonal crystal structure. When prepared in this crystal structure the iron-nickel composition particles are magnetically anisotropic and have useful permanent magnet properties.
[0006] In accordance with the invention, solid particles of iron and nickel are introduced into a process medium which is initially a plasma or plasma stream and which quickly heats the particles to form a vapor of iron and nickel atoms. The plasma is suitably formed, as in a DC plasma torch, from a neutral material such as nitrogen that does not chemically react with iron or nickel during their residence in the plasma processing medium. Preferably, the plasma is an element that is not condensable to a liquid at a temperature above 25° C. The plasma is initially at a temperature of many thousand degrees Kelvin, for example, 10,000 Kelvin, and a vapor of a mixture of iron and nickel is quickly formed. A very cold (below about 100K), inert fluid, such as liquid argon, or its vapor, is introduced into the plasma processing medium, containing iron-nickel vapor, to cool the iron-nickel mixture very rapidly to a temperature below 300° C. The vapor mixture of iron and nickel is rapidly transformed into particles of iron and nickel having a particle size smaller than about 250 nanometers. This process is utilized to quickly form and separate particles in which iron and nickel atoms are organized as successive layers of iron atoms and of nickel atoms in the arrangement characteristic of the L1 0 -type tetragonal crystal structure.
[0007] Preferably, each quenched particle consists of a single crystal of the iron and nickel atoms in the tetragonal L1 0 crystal structure. But, if necessary, particles that are partly amorphous, or have a high density of crystallographic defects such as dislocations may be carefully heat treated in an inert gas atmosphere to complete crystal formation. The heat treatment may be performed in the presence of an applied magnetic field in order to impose a preferential direction for formation of the L1 0 structure. But the particles must not be heated to a temperature (above about 320° C.) at which the crystal structure may convert to a disorganized crystal arrangement of the iron and nickel atoms. The nanometer size particles are collected and available for consolidation into a desired magnet body shape.
[0008] In accordance with a preferred embodiment of the invention, a flowing plasma stream is generated like that, for example, produced in a DC plasma generator or torch. A steady stream is established in a defined flow path. The plasma stream may have a generally circular cross-section. Solid pieces or particles of iron and nickel are introduced into the plasma stream. Preferably, but not necessarily, iron and nickel particles are introduced separately into the plasma, each at a plurality of locations around the perimeter of the flowing stream. The iron and nickel materials are quickly vaporized and mixed in the flowing plasma stream.
[0009] When the vapor/plasma process stream has been suitably established, a cryogenic fluid, such as liquid argon or liquid helium, is introduced into the vapor steam in an amount suitable to quench the iron-nickel vapor and form nanometer-size particles of iron and nickel composition. It is intended that the particles be cooled to a temperature below about 300° C. in the quench zone. As the quench fluid is added, the composite flowing stream may be confined and narrowed in cross-section so as to facilitate separation of the iron-nickel particles from the stream, and their recovery. The quenchant may also be separately recovered.
[0010] Preferably the additions of iron and nickel to the plasma processing stream are managed to produce single crystal particles of FeNi no larger than about 250 nm in size. In general, it is preferred that nickel constitutes about 25 to 67 weight percent of iron and nickel content of the particles. In one embodiment it is preferred that nickel constitutes about 45 to 55 weight percent of the iron and nickel content of the particles, and in another embodiment it is preferred that nickel constitutes about 25 to 39 weight percent of the iron/nickel content.
[0011] A minor amount of an additive element (A) may be included in the iron and nickel materials introduced into the plasma processing medium. Preferably, A is one or more of the elements selected from the group consisting of titanium, vanadium, aluminum, boron, carbon, phosphorus, and sulfur. The overall iron, nickel, and additive combination is to comprise no more than about fifteen weight percent of A and, preferably, no more than about ten weight percent A. The additive may be used in an amount to stabilize the formation of the iron/nickel combination in its tetragonal L1 0 crystal phase.
[0012] Accordingly, a method is provided to form a mixture of iron, nickel, and optionally an additive, convert it to a vapor mixture, and rapidly condense nanometer size particles of an organized arrangement of atoms having the tetragonal L1 0 crystal structure. The particles may be consolidated into suitable magnet body shapes by practices such as sintering, hot pressing, hot deformation, spark plasma sintering, or the like. A magnetic field may be applied prior to consolidation to magnetize and align the particles. Alternatively, the particles may be consolidated and the solid body magnetized after consolidation. In either case, complex magnetization patterns (e.g., magnetic poles) may be imposed on the solid compact after consolidation using an appropriate magnetizing fixture.
[0013] Other objects and advantages of the invention will be apparent from a description of illustrative embodiments of the practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The drawing figure is an enlarged schematic illustration of an organized layered arrangement of iron atoms 10 and nickel atoms 12 in a single cell of a L1 0 tetragonal crystal structure. In this illustration, each layer of atoms of the crystal cell is filled with either iron atoms or nickel atoms. Because of the slightly different sizes of the iron and nickel atoms, the cell is tetragonal. This organized layered arrangement of the iron and nickel atoms provides their L1 0 tetragonal crystals with magnetocrystalline anisotropy. In this illustration, the preferred magnetic direction of the crystal cell is in the vertical direction. The use of additive atoms in the practice of the invention (not illustrated in the drawing figure) serves to enhance or stabilize this basic arrangement of the iron and nickel atoms in the basic L1 0 tetragonal crystal structure.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0015] In one aspect of the present invention, a method is provided to convert particles of iron and nickel, or particles of an alloy of iron and nickel, using vapor phase and quench processing into nanometer size particles of single-crystals of iron and nickel atoms which are organized in a L1 0 tetragonal crystal structure.
[0016] The method comprises the formation of a plasma volume or stream, created using a composition that does not react chemically with the iron or nickel. Preferably, but not necessarily, the plasma is formed and used as a flowing high temperature stream to which the iron, nickel, and additive elements, if used, are added. The plasma may be formed from a suitable gas that does not chemically alter the iron or nickel. The gas may be, for example, helium, argon or nitrogen. The plasma initially is at a very high temperature of the order of several thousand degrees Kelvin. The plasma is used in the present process to form a high temperature processing medium into which iron and nickel particles are added and vaporized to form a quenchable mixture. As described above in this specification, the vapor mixture is maintained only for a brief period of time and is then quenched to condense the iron, nickel, and any additive atoms as a solid mixture in the form of very small particles. In general, it is preferred to use the plasma in the form of a flowing process stream with a generally round cross-section, or like perimeter, to facilitate the addition of the starting particles at a plurality of locations around the circumference of the plasma stream.
[0017] Thermal plasmas are often generated in plasma torches when a flowing gas is energized by an electrical discharge, such as a direct current (DC), alternating current (AC), or radio frequency (RF) discharge. A plasma stream in the nature of a DC torch stream is suitable for use as the high temperature processing stream. In a typical DC plasma generator, a gas stream of nitrogen (e.g.) is flowed through a circular tube, along an axial cathode toward an anode ring near the outlet of the tube. A high voltage DC arc discharge is maintained between the downstream end of the axial cathode, near the anode ring. As the nitrogen passes through the DC discharge at a suitable flow rate, it is converted into a highly ionized gas; a plasma. The use of a plasma processing stream is preferred in the practice of this invention because the flowing stream may be quickly and effectively utilized to receive additions of iron, nickel, and additive, to affect their conversion to a mixed vapor, and to accommodate the quenching of the vapor to recover very small, rapidly solidified particles of the permanent magnet material. Accordingly, it is preferred that the stream is established with a generally circular cross-section. Thus, the plasma stream may be enclosed or otherwise formed with a defined periphery, suitable for the addition of the iron, nickel, and any additive solids to be processed.
[0018] Thus, as soon as the plasma processing stream has been established, it is utilized. Suitable amounts and proportions of iron and nickel particles are injected into the high temperature stream so that they are quickly melted and vaporized. In general it is preferred to utilize the plasma processing stream by introducing the solid materials at several locations around the periphery of the stream and, if necessary, along the flow path of the plasma stream. In a preferred embodiment, iron particles and nickel particles are separately introduced into the plasma stream. When the product is to contain an additive element or elements it may be preferred to pre-form alloys of the iron, nickel, and additive(s). The materials may be added, for example, in predetermined proportions by pushing individual or alloyed particles through feed tubes into the flowing plasma stream. Of course, the rate of addition of the iron and nickel must be in proportion to the capacity of the plasma stream to receive them and immediately melt them to form a vapor of the metal elements to be mixed. Thus, a continuous length-wise portion of the flowing plasma processing stream is utilized to receive and rapidly melt and vaporize the predetermined combinations of iron, nickel, and any additive elements to be prepared as a vapor suitable for quenching. Depending on the predetermined thermal capacity of the plasma process stream, less than a meter or so of its flowing length may be required for this step of the process.
[0019] When a suitable vaporized mixture of the elements has been formed, the mixed vapor is quenched to recover the added elements in the form of small solid iron-nickel-based particles. By this stage of the process, the initially plasma material may have cooled into a high temperature gas that is carrying the metal vapor. Again, the generally confined perimeter of the flowing process stream may be utilized for the effective addition of a very low temperature (cryogenic) quench fluid into the stream. Preferably, the quench fluid is directed into the process fluid in several radially inwardly-directed streams applied from the circumference or perimeter of the flowing process stream.
[0020] Liquid argon (initially at about 83 Kelvin) is a preferred quench fluid. Of course, argon has a very narrow liquid temperature range and will soon be converted to a vapor as it encounters the plasma process stream. Liquid helium or liquid nitrogen may also be used as a quench fluid. In order to better utilize the quench fluid and the process stream, it is preferred to add quench fluid from a plurality of locations around the perimeter of the flowing process stream.
[0021] The addition of the quench fluid increases the mass of the flowing stream as it is cooled. If the flowing process stream has not been physically combined within a tube or the like to preserve its thermal content, the quenched process stream may now be directed into a confining tube or the like. The cross-section of the process stream may initially be allowed to expand and cool. But it is then desired to funnel or narrow the stream in which the solid particles of iron and nickel are being formed. This is to facilitate separation of the precipitated iron-nickel-additive particles from the process stream. It is, of course, desirable to completely recover all metal added to the plasma stream. This may be accomplished by passing the channeled, particle-containing, process stream through a suitable filter or centrifuge.
[0022] It is also generally desirable to recover the argon or other quench material for reuse. It may also be desirable to recover the working gas used to form the plasma.
[0023] The practice of the described process is to form generally uniformly-sized particles of (Fe 100-x Ni x ) 100-y A y composition where the particles are no larger than about 250 nanometers in diameter or largest dimension. A representative sample of the particles may be examined and characterized by X-ray diffraction.
[0024] Preferably, the particles consist of single crystals of the (Fe 100-x Ni x ) 100-y A y composition and in the tetragonal L1 0 crystal structure. A schematic illustration of a single crystal cell is presented in the drawing Figure. It is seen that alternate layers of the cell consist of iron atoms 10 and nickel atoms 12 . Ideally, this alternate layer arrangement of the iron and nickel atoms, with interspersed additive atoms (if included) would continue throughout the cells of a single crystal particulate material
[0025] If the quenched particles are not fully crystallized, they may be heat treated in an inert atmosphere at a temperature below about 300° C. for a time determined experimentally, or by experience, to complete the crystallization of the quenched particles. Other methods of inducing complete crystallization in the recovered particles include pressurization under a suitable gas, or application of an applied magnetic field, or combinations of the above, such as heat treatment in the presence of an applied magnetic field. Also mechanical processing of the particles such as rolling, swaging, or ball milling of the particles may be utilized to complete crystallization in the small particles. Combinations of these practices may also be used to induce further crystallization.
[0026] The process is conducted to obtain the (Fe 100-x Ni x ) 100-y A y composition in the form of particles having the magnetically anisotropic, tetragonal, L1 0 crystal structure. Preferably, each particle is a single crystal of the desired structure. As stated it is preferred that the nickel content of the iron-nickel mixture be, by weight, 25 to 67 percent of the total of iron and nickel; x=25-67. Within the overall preferred proportions of iron and nickel are two preferred sub-ranges by weight which are found to reflect good combinations of iron and nickel. These weight ranges are reflected by x=45 to 55 weight percent Ni and x=25 to 39 weight percent Ni.
[0027] When one or more additives (A) are added with the iron and nickel, it is preferred that y be no greater than 15 percent by weight of the total of Fe, Ni, and A. More preferably, it is preferred that y be less than or equal to 10% by weight. It is preferred that an additive, A, is selected to be one or more elements selected from the group consisting of Ti, V, Al, B, C, P, and S.
[0028] In many permanent magnet applications it will be necessary to consolidate the iron-nickel particles into permanent magnet body shapes for use in electric motors, magnetic actuators, and the like. Such consolidation may be accomplished by any of many suitable methods which do not adversely affect the desired tetragonal L1 0 crystal structure of the particles. A permanent magnet may be formed by magnetizing and magnetically aligning the particles prior to consolidation, or by magnetizing the solid body in its entirely, or in regions, after consolidation is complete.
[0029] Practices of the invention have been disclosed as specific illustrations which are not intended to limit the proper scope of the invention. | Particles of iron and nickel are added to a flowing plasma stream which does not chemically alter the iron or nickel. The iron and nickel are heated and vaporized in the stream, and then a cryogenic fluid is added to the stream to rapidly cause the formation of nanometer size particles of iron and nickel. The particles are separated from the stream. The particles are preferably formed as single crystals in which the iron and nickel atoms are organized in a tetragonal L1 0 crystal structure which displays magnetic anisotropy. A minor portion of an additive, such as titanium, vanadium, aluminum, boron, carbon, phosphorous, or sulfur, may be added to the plasma stream with the iron and nickel to enhance formation of the desired crystal structure. | 1 |
This is a continuation of application Ser No. 08/227,567 filed Apr. 14, 1994 of application Ser. No. 08/101,400 filed Aug. 2, 1993, which in turn is a continuation of application Ser. No. 07/523,725 filed May 15, 1990 now abandoned, which in turn is a continuation of application Ser. No. 07/159,780 filed Feb. 24, 1988 (now U.S. Pat. No. 4,951,040).
This is a continuation of application Ser. No. 08/227,567 filed Apr. 4, 1994.
BACKGROUND OF THE INVENTION
This invention relates to electronic image processing systems, especially though not exclusively for processing video signals representing a television picture.
Electronic image processing systems are known, capable of capturing video signals representing a television picture and processing these signals to produce the effect of three dimensional manipulation of the picture. One such system is the Encore system manufactured by Quantel Limited of Newbury, Berkshire, England. With this system it is possible to produce a 3D spin of the picture or change the position, size, or view position of the picture using manual controls which include a tracker ball. To produce these effects, a frame store is provided in which is written a frame of video signals to be processed, and a processing circuit responsive to signals set up by the manual controls determines successive addresses in the frame store from the which successive video signals should be read, to build up an output frame containing the processed picture. The system is interactive, inasmuch as the writing, processing and reading is repeated frame by frame, the input in each frame period being formed by the output of the preceding frame period. A monitor is provided for displaying successive processed frames as a moving picture so that the operator can observe the effect of his manipulation of the controls in real time. During each frame period the processing circuit responds to the incremental control signals set up during the preceding frame. The processing circuit may for example be of the construction described in our British Patent No. B 2,073,988. (equivalent U.S. Pat. No. 4,437,121).
One use to which systems such as described in the preceding paragraph may be put is that of transforming a flat picture so that it can be placed exactly over a polygonal shape (usually quadrilateral) on another picture to build up a composite picture. For example the first picture may be a view through a window and it may be required to place the picture over the window seen from different positions. It is possible to achieve this result using the existing controls on the Encore equipment, but in practice it is a difficult and time consuming process as it may involve a combination of spin—and changes in size, position and point of view of the picture to be superimposed.
One early proposal for solving the above difficulties, attempted in-house by the assignee of this application, involved processing equipment comprising means for defining the corner positions of a picture and means for transforming the addresses of the picture points of the picture to fit the picture over the quadrilateral defined by the corner positions, assuming a given viewpoint. In this in-house attempt, the transformation was carried out in one operation and was not interactive. This technique may have been included before the priority date of this application in equipment available from the assignee under the trade name Graphic Paintbox (GPB).
The object of the present invention is to provide an improved image processing system in which effects such as that described in the preceding paragraph can be more easily achieved.
SUMMARY OF THE INVENTION
According to the present invention there is provided an image processing system comprising a source of picture video signals representing picture points at respective addresses in a first picture projected on a viewing screen, characterized by addressing means for providing address signals representing the addresses of at least four reference points defining corners of a polygon notionally projected on said screen, operator controlled means for producing selective adjustment of said address signals to cause said reference points to define the corners of said polygon as projected on said screen after a movement of said polygon in 3D space, transform means responsive to said address signals after said selective adjustment, for transforming the addresses of said picture video signals so as to cause the picture video signal to represent the picture as projected on said screen after undergoing the same movement in 3D space as said polygon.
The operator-controlled means includes means for selecting the reference points one by one and adjusting the address of the reference point selected at any one time whilst leaving the address for the other reference points unchanged. The transforming means may include means for setting up equations relating the addresses of the reference points at one time with the addresses of the reference points at a later time, means for solving said equations to derive the coefficients defining the movement of said polygon in the interval between said times, predicated upon the operation of said operator-controlled means, said transforming means being responsive to said derived coefficients to tranform the addresses of said picture video signals. Preferably said operator controlled means includes cursor means for providing cursor signals to represent said reference points (which signals may be the corner signals of said first picture), frame store means for storing said cursor signals at the addresses provided by said addressing means (which may be the addresses of the picture corners), reading means for reading said reference signals from said frame store means in successive frame periods and means for displaying said reference signals as read from frame store means. The operator is thus able to observe the successive projection of the polygon defined by the reference signals and also of said picture, and by operating said operator-controlled means can “pin” the reference points, one at a time, at four predetermined points on the screen. As thus pinned, the picture is corrected for perspective.
The operator controlled means may include means for selectively adjusting at one time (if desired) the addresses of more than one of the reference points. Where more than one reference point is selected, the same adjustment is imparted to all the selected points. The operator controlled means may include a tracker ball for setting up the x and y co-ordinate of an displacement. Alternatively it may include a touch tablet-stylus combination. It will be understood that, if all four corners are selected at one time, the displacement of the corners will represent a translation of the image without spin or change in the viewpoint.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 a to 1 d are diagrams illustrating one application of corner pinning according to the invention.
FIG. 2 is a perspective view illustrating a flat rectangle and a transformation thereof into 3D space.
FIG. 3 illustrates the projection onto a screen of a transformation into 3D space.
FIGS. 4 a , 4 b and 4 c illustrate respective projections of a flat object subjected to one-axis rotation.
FIG. 5 illustrates a view hemisphere on a screen.
FIG. 6 is a block diagram of the said example of the invention.
FIG. 7 is a block diagram of a modification of the FIG. 6 example.
FIG. 8 is an explanatory diagram relating to FIG. 7 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, in FIG. 1 a , rectangle ABCD represents a boundary on a television picture representing a scene projected on a viewing screen. Initially, the boundary coincides with the edges of the television frame although it is not necessarily the case. It will be appreciated that the picture will be formed by video signals representing respectively a series of picture points in each of a series of lines in well known manner and it will be assumed that video signals are stored in a frame store. The number of a particular picture point in a line and the number of the respective line in the television frame, determine x, y co-ordinates (the address) for the picture point in the store. For the purpose of illustrating the invention, before describing the example of the invention shown in FIG. 6, its operation in transforming the boundary from the rectangular shape ABCD to the quadrialteral A′B′C′D′ on the screen will be described.
The first step is to move the corner A of the picture boundary to the point A′ in the television frame. The system according to the invention has operator-controlled means which the operator can use first to designate corner A for processing and then to feed in signals representing the two component displacements, dx, dy required for the corner. The control signals form a command to transform the addresses of the video signals in the television frame so that the original boundary ABCD is transformed into the boundary A′BCD. This means that all video signals for points in the boundary line AB (coinciding, it is assumed, with the first line of the television frame) are readdressed to the line A′B. Similarly signals for points on the boundary line AD have to be readdressed to the boundary line A′D. Therefore the video signals on line AB and AD have to be moved to new ‘addresses’ defining the lines A′B and A′D, in the same or a different frame store so that when read out for display they will occupy different positions on the television raster. All other points on and within the boundary ABCD have to be similarly readdressed to appropriate positions within the transformed boundary A′BCD. The transformation is effected by using the x,y co-ordinates of the original corners ABCD and those of the moved corner (only A′ in this case) to derive coefficients which are definitive of the spin, position and view position changes which would be required to make A′BCD the projection on the viewing screen of the original boundary ABCD, after subjecting it to the said spin, position and view position changes. For example picture point m in AB may have its projection at m′ in A′B. It will be appreciated that distances which are in one ratio on AB would generally not be in the same ratio in A′B, since projection is involved.
In the foregoing it has been assumed that the transformation of ABCD to A′BCD was made in one step. According to the invention, however, in the system shown in FIG. 6 the change is made interactively over several frame periods in response to successive incremental changes in x,y for the corner A. In any one frame period, an incremental transformation is effected in response to the incremental changes in x and y for the selected corner, effected by the operator in the previous frame period. The system includes a monitor which displays the transformed frames in succession and so provides the operator with a moving display of the original picture as it is progressively transformed. He is thus able to control the movement to achieve the desired effect.
It have also been assumed that when addresses are transformed, from line AB to line A′B for example, there will be a storage location in the respective frame store with the transformed address for each picture point in the initial image. In practice, a transformed address will in general turn out to be somewhere in a rectangle defined by two storage locations in each of two adjacent lines of the frame store. The video signal for a picture point when translated to the new address may therefore have to be ‘interpolated’ among the respective four addresses. One means of achieving such interpolation is described in the aforesaid British Patent 2073988 (equivalent U.S. Pat. No. 4,437,121) but with a view to simplifying the description of the present invention, it will continue to be assumed that there is a one to one corresponding between transformed addressess in the transformed picture and storage location in the frame store. When movement of the first corner is complete, the transformed picture will have the original boundary A′BCD within a rectangular frame ABCD. The original picture point information will all be on or within the boundary A′BCD, and none in the space ABA′D. The operator then uses the control means to select corner B and inserts displacement signals to move corner B to B′. The transforming circuit responds by transforming the boundary A′BCD to A′B′CD as indicated and to transform other picture points within A′BCD correspondingly.
The procedure is repeated for corners C and D resulting in the original picture being transformed so that the boundary becomes A′B′C′D′, occupying only part of the television frame. As a practical application, assume than the original picture ABCD was a view of a garden, seen looking straight out of a window for example. The transformation enables the scene to be positioned exactly over a window to build up a composite scene.
Consideration will now be given to the algorithm used for effecting the transformations required to put the invention into practice. Referring to FIG. 2, it is known that the image of an object which sits on a flat viewing screen (as displayed on TV monitor say) is transformed into 3D space using the equations:
x′=ax+by+kz+c
y′=dx+ey+lz+f
z′=gz+hy+mz+j
or in matrix form ( x ′ y ′ z ′ 1 ) = ( x y z 1 ) ( a d g o ) ( b e h o ) ( k 1 m o ) ( c f j 1 )
In these equations, x y define the position of an image point on the original screen., z a distance measured normal to the screen, and x′ y′ z′ are the co-ordinates of the respective image point moved in 3D space. The coefficients a, b, c . . . are determined by the spin, position or size change required to effect the movement.
The object now sitting, as a result of the transformation, in 3D space behind the screen, must be projected back onto the viewing screen (as it would be seen by a person sitting at the viewing position (Vx Vy Vz) on the opposite side of the viewing screen, as indicated in FIG. 3 . The co-ordinates x″ y″ z″ define the position of an image point when projected back. The co-ordinate z″ will be zero it the plane of the screen is taken to be z=0.
If we consider the projection of the x′ co-ordinate onto the screen at x″ as in FIG. 3, by similar triangle we have: x ″ = x ′ V z + z ′ V x V z + z ′ and similarly y ″ = y ′ V z + z ′ V y V z + z ′
The 3D transformation set out in relation to FIG. 2 can be substituted into these projection equations to allow transformation of each picture point on a 2D to 2D basis. Such a 2D to 2D transformation produces a projection of the original object after subjection to the spin, position and size changes implicit in the 3D equations.
It can be shown that the 2D to 2D equations are of the form: x ″ = A x + B y + C G x + H y + 1 and y ″ = D x + E y + F G x + H y + 1
In these equations the capital letters ABC . . . are not the a, b, c . . . of the 3D equations though they are again related to the spin, position and size changes implied by the movement of the corner.
As the 2D to 2D transformation equations are known, it is believed to be unnecessary to demonstrate the mathematical derivation of the coefficients A to H. For a fuller treatment reference may be had to “Principles of Interactive Computer Graphics”, Second Edition, W. M. Newman and Robert F Sproull, published by McGraw-Hill Internatioanl Book Company—see especially Chapter 22, page 333.
Applying the equations to the present invention, advantage is taken of the fact that for any particular transformation the starting and finishing co-ordinates of the reference points, the four corners of the pictures, are known. There are therefore four equations in x and four in y which can be set up after each incremental displacement of one or more corners in which these known co-ordinates can be entered, and the equations solved to evalute the coefficients A to H for the particular frame transformation. Using the coefficients thus evaluated, the transformed address for every other picture point in the initial picture can be evaluated.
The projection equations are capable of producing x and y shear or view position change on the input image, as illustrated in FIGS. 4 ( a )- 4 ( c ) which show possible projections of an original image subjected to one axis rotations (spin) from flat on the screen. By comparing FIGS. 4 ( b ) and 4 ( c ), it can be seen that it would be impossible in some circumstances to produce a required shape without changing the viewing position from an initially assumed position, or introducing shear of the original image. Also various arrangements of an object and the viewer may produce the same projection.
This means that a displaced corner such as A′ could be the projection of more than one point in space, depending on the viewing position. There is no unique solution for the coefficients A . . . H and it is therefore necessary when evaluating them for a particular movement to postulate limitations on the viewing position which reject unrealistic projections.
Therefore, on feeding the value of the viewing position back into the machine to effect the address transformations, the system is arranged so that certain conditions have to be satisfied. The viewer has to be on the outside of the screen and the transformed picture behind it. The viewing position is the closest possible to the origin of the screen and a limit for the minimum viewing distance is chosen to be the limit for which 3D controls remain usable. The value for j (which, in the equations above in relation to FIG. 2, is the x and y independent distance of z into the screen) is calculated to produce one side as close to unity as possible and the other to be less then or equal to it.
It has been found in practice that the above conditions are satisfied and acceptable results can be achieved by postulating that the viewing position shall lie on the surface of a hemisphere sitting on the screen and having as a diameter a line joining the vanishing points P 1 P 2 of the projection, as indicated in FIG. 5, assuming four reference points. Spin between FIG. 4 ( a ) and FIG. 4 ( b ), for example, then becomes realistic. Other sets of conditions may be devised.
In the example of a system according to the invention shown in FIG. 6, two frame stores 1 and 2 are provided, having storage locations for storing digital video signals representing every picture point in a television frame. The stores would normally have more than one plane for storing different colour components for each image point in corresponding addresses in the different planes. Video signals representing a picture can be written in each store either from an external source or from the other store, under control of switching circuits 3 and 4 . Writing is under control of a write address generator 5 timed by a clock running at picture point frequency so that picture point video signals are written sequentially in the frame store locations in television raster format. The write addresses are applied alternately for frame periods to the store 1 and 2 via a switching circuit 6 . Reference 7 denotes a read address generator which generates transformed read addresses for reading video signals from selected addresses in one or other of the frame stores at a picture point rate. The read addresses are applied alternately for frame periods to the stores 1 and 2 via a switching circuit 8 , which is synchronised with switching circuit 6 so that when read addresses are applied to one store ( 1 say) write addresses are applied to the other. The video signals output form the stores 1 and 2 , when read addresses are applied to them, are fed back as aforesaid to the switching circuits 3 and 4 and are also applied to a monitor 9 having a display screen 9 a on which successive frames of video signals, read from the stores 1 and 2 and applied to the monitor 9 via switching circuit 10 , can be continuously displayed. The operator may also, by means of selector 12 cause related frames of video signals to be applied to a disc store 13 for storage therein.
The address generator 7 constitutes the transforming circuit referred to previously in the specification. It receives inputs from an operator controlled corner displacement generator 14 , and from a corner designator 15 . The corner designator is also operator-controlled and applies signals to the circuit 7 to determine which corner of a picture is to be displaced at a particular time to effect corner pinning. The generator 14 , which may comprise a tracker ball, applies signals to the circuit representing the x and y displacements of the selected corner or corners required by the operator. If more than one corner is selected by the operator, the displacements x y set up by the generator 14 are applied to all the selected corners. The selector 15 is arranged to provide not only a designation of the selected corners, but also the address of all the corners prior to the most recent adjustment. The address adjustment, though effectively tracking the x and y displacements signalled by the generator 14 , occurs in steps during each frame period in response to the displacement signalled by the generator 14 in the preceding frame period. The transforming circuit 7 includes means 16 responsive to the inputs from the generator 14 and selector 15 to evalute the coefficients A to H of the 2D to 2D transforming equations referred to in the foregoing. The coefficients are applied to means 17 which uses them to solve for each picture point in an initial picture, the addresses to which that picture point must be assigned in the television raster to cause the picture to be transformed to the projection of the initial picture, subjected for the spin, position or view position changes implied by the displacement of the corner or corners signalled by the outputs of 14 and 15 . The evaluations here referred to are subject to conditions which are imposed on the viewing position. The addresses generated by the means 17 are produced at picture point rate. As will be appreciated from the theory described above the addresses generated by the means 17 are addresses to which the successive picture point video signals of the initial picture should be moved in the output raster. However, the addresses produced by the transforming circuit 7 are used in a reading mode to select different addresses from which the untransferred video signal are read from store 1 or 2 , so it is necesssary to invert the addresses from the means 17 and this is carried out in address inverting means 18 . The picture point video signals read from store 1 or 2 as the case may be are therefore in correct order in the raster to represent the transformed picture.
In using the system illustrated in FIG. 6, a picture to be transformed may be read from store 13 and written in one of the stores 1 and 2 , (say 1 ) during a first frame period. During the next frame period this picture is transferred in response to any inputs applied to circuit 7 by the operator and read from the store 1 and written into store 2 . The picture in store 2 is then transformed during the next frame period by the circuit 7 in response to inputs made by the operator during the previous frame period, and so on until a desired transformation is completed. In making the transformation, the operator can continuously observe the effect he is creating on the screen of the monitor 9 . The synchronisation of the switching circuits 3 , 4 , 6 , 8 and 10 to achieve the desired mode of operation can be effected under computer control.
The transforming circuit 7 may in fact be constituted by a suitably programmed computer and this computer may indeed also be programmed so that it can leave the corner pinning mode and effect other transforms such as spin, size, position and view position control which are available in current Encore systems. Means may also be provide, as previously indicated, for effecting interpolation of picture point video signals as required, when a. transformed address does not not coincide with an address of a storage location in the stores 1 and 2 ). Further means may be provided to reduce changes in the brightness of the transformed picture due to compression or expansion of part of the image.
Transformed pictures produced by the system illustrated in FIG. 6 can be keyed into other background pictures to form composite pictures, so that the corner points are “pinned” at predetermined reference points in the background picture or used in other ways. The invention is not confined to television and it could be used in the general graphics field.
The example described with reference to FIGS. 1 to 6 operates to pin corner points of an image originally rectangular, to the corners of a quadrilateral seen in perspective. The invention is not, however, confined to systems which operate on this basis and FIGS. 7 and 8 illustrate the use of the invention to transform an image of any shape so that reference points on the image can be pinned at predetermined points on a surface in another image (called the scene image), which may be represented as seen from an arbitrary view point. In FIG. 7, references 21 to 24 denotes frame store means for storage respectively of (a) cursor video signals representing a cursor, (b) first picture video signals representing an object to be introduced in a scene (picture 1 ), (c) second picture video signals representing the scene (picture 2 ) and (d) stencil video signals which in known manner represent a control image (stencil).
Each of the frame store means may be as described in relation to the frame stores 1 and 2 in FIG. 6, and they have source inputs 25 to 28 from which respective video signals may be applied for storage. Reference 29 denotes write address generating means whereby incoming video signals are written in the correct addresses in the frame store means, determined by the position of the video signals in the signal raster. Reference 30 , on the other hand, denotes a read address generator which can be operated to read video signals from the store means 21 to 24 . The read address signals for the store means 21 , 22 and 23 are however applied to the respective store means via address transforming means 31 similar to means 7 in FIG. 6 .
Reference 32 denotes a combiner 32 for video signals read from the store means 21 to 24 and is controlled by a selector 33 which is operator controlled, and can condition the combiner 32 to superimpose cursor video signals from store means 21 on picture 1 or picture 2 read from store means 22 or 23 , or superimpose part of picture 1 on picture 2 read from 23 under control of the stencil from store means 24 . The superimposition may be partial, whereby the upper picture appears translucent, or may be complete, the upper image then appearing opaque. Video signals output from the combiner are applied to a display device 34 corresponding to device 9 in FIG. 6, and may also be applied to disc storage means 35 for long term storage. The operation of the frame store means 21 to 24 , of the write and read address generator 29 and 30 , the combiner 32 and its selector 33 are well known and need not be further described. The combiner 32 may also be conditioned if desired by the selector 33 to pass the signals from any one of the storage means 21 to 24 uncombined with other signals, to the display means 34 .
Reference 41 denotes a touch tablet-stylus combination which in this example of the invention can be manipulated to provide address signals representing the addresses of reference points defining the corner of say a rectangle which is used to position picture 1 or picture 2 . The touch tablet-stylus combination also provides the operator with means for producing selective adjustment of these addresses to represent positional adjustment of the rectangle. As the operator applies the stylus 45 to different points on the touch table, x y co-ordinate signals of the points are fed to a computer 42 which in turn is connected to a cursor video signal generator 43 . The computer 42 has a mode selector 44 by which the operator can condition the computer to perform different functions. The stylus 45 of the combination 41 has a connection 46 for supplying the computer 42 with a signal representing the pressure with which it is applied to the touch tablet, but this need not be discussed in this application.
As already indicated, the system illustrated in FIG. 7 can be used for “pinning” an image of any shape on another image. In FIG. 8 reference 50 denotes a representative non-rectangular image constituting picture 1 , the image being shown simply as a circle for convenience. In order to pin this image on picture 2 , the operator writes the respective video signals from source 26 into the frame store means 22 and conditions the combiner 32 , using the selector 33 , to combine the video signals in frame store means 22 with those in frame in store means 21 (cursor) and apply the combination repetitively during successive frame periods to the display means 34 . Initially, frame store means 21 will contain no cursor video signals, so the display means will display merely picture 1 , without any superimposed cursor. The operator then selects the cursor generation mode, using selector 44 and while observing the picture 1 in the display operates the stylus 46 to designate four reference points on the image 50 , say the points 51 , 52 , 53 , 54 shown on FIG. 7 . The addresses of these points are fed from 41 to the computer 42 where they are temporarily stored. The computer in response to these address signals causes the cursor generator to produce cursor video signals, in timed relationship with the write addresses from generator 29 , to set up in store 21 a video image of a suitable cursor defined by the four reference points. In FIG. 8 the cursor image is shown as a simple rectangular grid (shown in dotted lines) with corners located at the reference points 51 to 54 . The cursor grid need not be initially rectangular, though in general it must be based on at least four reference points. In principle it could be a polygon of four or more sides.
After generating the cursor, the operator, using the stylus 2 , marks on the cursor image the positions on picture 2 at which the four reference points should be pinned. While doing this the operator may temporarily superimpose the cusor image on picture 2 , via the combiner 32 . For example, the position at which reference point 52 should be pinned is indicated at 52 a . The operator then conditions the computer 42 for generating the address transforms and conditions the combiner 32 to superimpose the cursor image on picture 1 and display the combination on device 34 . Having done so the operator selects a reference point (in this case point 52 ) by pressing the stylus down on the corresponding point on the touch tablet, he then moves the stylus 46 on the touch tablet to drag reference point 52 to point 52 A at which pinning is desired, causing the successive generation of new address signals for reference point 52 as the position of this point is adjusted. At the end of each frame period, while this adjustment is taking place, the addresses of the four reference points (including the adjusted address), together with the addresses as they were at the beginning of the period, are used in the computer to set up and solve the equations for evaluating the co-efficient A . . . H referred to above. These are fed in turn to the address transforming circuit 31 , to produce the desired transformation of the read addresses for the store means 21 and 22 , so that as the position of reference point 52 is adjusted the display means 34 displays picture 1 as if projected on the viewing screen after undergoing the same movement in 3D as implied for the rectangle 51 - 54 by the adjustment of the address of reference point 52 . The same process of adjustment is repeated for each reference point until all of them are positioned at the pinning points derived from picture 2 . The transformation is, moreover, carried out interactively whilst the image of picture 1 with the superimposed cursor is displayed.
It is noted that address transformations are carried out by the circuit 31 for all picture points in the cursor image stored in store means 21 and for all picture points in picture 1 stored in store means 22 . The address transformation is not limited to picture points with the rectangle initially defined by the reference points 51 to 54 . The cursor grid may itself, if desired, initially extend over the whole screen. When the transformation is complete, the image 50 forming picture 1 , as transformed, can then be superimposed on picture 2 under control of the stencil video signals from store means 24 , the combiner 32 being suitabley conditioned for this purpose. The control image formed by the stencil signals may be such that the whole or a part of the picture 1 may be selected for superimposition i.e. picture 1 may be cropped, but in any case the superimposition will be effected in such a way that the four reference points initialy selected by the stylus 46 will be “pinned” at the four chosen points on picture 2 .
It will be understood that the modes of operation described with reference to FIG. 6 and FIG. 7 can both be provided in one system if desired. The algorithm used for effecting the address transformations may be similar but as FIG. 7 is a more general case of projecting any quadrilateral, and not simply a rectangle as in FIG. 6, the transformations are more complex. The procedure used for selecting the view position, in the FIG. 7 system may also be modified. The matrix values such as A B C . . . for an arbitrary view position are first calculated and these values used to calculate the projection of an imaginary rectangle. This projection is then used to postulate a realistic view position for the original quadrilateral using the model illustrated in FIG. 5 .
In the FIG. 7 systems it is possible, as in FIG. 6, to select more than one reference point at a time for adjustment, a suitable control routine being prescribed for picking out the described number of reference points to be moved at the same time. Other modes of operation mav also be provided for. In one such mode the operator can define four reference points, and then select a further point about which he can spin the picture by “dragging” the stylus from the further point in a prescribed manner. In another so called “size” mode, two sides of the quadrilateral are “moved” by means of the stylus so as to maintain the angles made by the corners. This has the effect of altering size in 3D space. | A pixel image at broadcast or graphics resolution is spatially transformed to represent the 2D projection of an image that has undergone movement in 3D space or is seen from a different viewer's position. For example, an image on a screen is delineated with four reference points designated by touching a pen on a tablet and then one is dragged with the pen along the screen to change the shape of the delineated image. At the same time, the entire delineated image is spatially transformed to make it continue to fill the entire changing shape and only that shape, until the dragged reference point is pinned to fix its position on the screen. Two or more designated point can be selected to move together as the pen drags them along the screen. The image being spatially transformed can be combined with a second image under the control of a stencil image to form a composite image. | 7 |
FIELD OF THE INVENTION
[0001] This disclosure relates to a tissue carton comprising a stack of compressed tissues. Various compressed tissue cartons are disclosed. By providing a carton with an oversized carton opening it has been discovered that the compressed stack of tissues may be dispensed normally by a user.
BACKGROUND
[0002] When shipping folded tissue products, such as cartons of facial tissues, a significant portion of the transportation costs incurred are due to shipping air because of the low density of the tissues. Consequently, when shipping by truck, for example, the volume capacity of the truck is reached before the weight capacity. Also, on the retailers' shelves, the bulkiness of the tissue products consumes shelf space and therefore limits the number of items the retailers can stock. Unfortunately, placing more tissues into a given carton to increase shipping cost efficiency and/or reduce consumption of retail shelf space creates compression within the stack of tissues and thereby makes it difficult for the user to remove the first few tissues from the carton without tearing them.
[0003] While the retailer often desires products which use less shelf space, there are disadvantages to using compressed or concentrated products. For example, one disadvantage is that compressed tissue stacks dispense poorly when packaged in traditional flat tissue cartons. Therefore, there is a need for tissue products that can be shipped more economically without sacrificing ease of dispensing or presence of the product on the retailer's shelf.
SUMMARY
[0004] It has now been surprisingly discovered that compressed tissues may be dispensed with ease by packaging the tissues in a carton having an oversized carton opening. The preferred carton opening size is generally from about 110 percent to about 275 percent greater than the opening size found on traditional, non-compressed tissue cartons. Thus, in a preferred embodiment the present disclosure provides a carton for dispensing a compressed stack of tissues, the carton comprising a carton opening located on a top panel, the area of the carton opening comprising from about 50 to about 85 percent of the area of the top panel. In this preferred embodiment, tissues may be compressed significantly, reducing the overall height of the carton, without negatively impacting ease of dispensing.
[0005] In other embodiment the present disclosure provides carton comprising a top panel; a first and a second sidewall; a carton opening located in the top panel; and a dispensing window covering at least a portion of the carton opening; wherein the area of the carton opening is from about 50 percent to about 85 percent of the area of the top panel.
[0006] In still other embodiments the present disclosure provides A carton for dispensing a compressed stack of tissues comprising a top panel; a carton opening disposed on the top panel, the carton opening having an area that is from about 50 percent to about 85 percent of the area of the top panel; a pair of side panels; a dispensing window covering at least a portion of the carton opening and a portion of at least one side panel; a dispensing opening disposed on the dispensing window; a removable surfboard overlaying at least a portion of the dispensing window; a compressed stack of tissues; and a bottom panel.
[0007] In other embodiments the present disclosure provides a carton for dispensing compressed interfolded disposable sheets comprising a dispensing carton configured to house a stack of compressed interfolded disposable sheets and having a plurality of sides defining an interior space, the carton having a carton opening disposed on at least one side, wherein the area of the carton opening is from about 50 percent to 85 percent of the area of the side on which it is disposed.
[0008] In yet other embodiments the present disclosure provides a method of making a carton of compressed tissues comprising the steps of providing a dispensing carton having a top panel and a carton opening disposed thereon, wherein the ratio of the area of the top panel to the area of the carton opening is from about 50 to about 85 percent; compressing a stack of tissue sheets; and inserting the compressed stack of tissue sheets into the dispensing carton, whereby the stack of tissue sheets is constrained within the expandable dispensing carton in a compressed condition.
DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 illustrates a tissue carton dispenser according to one embodiment of the present disclosure;
[0010] FIG. 2 illustrates a cross-section of the embodiment of FIG. 1 taken at line 1 - 1 ;
[0011] FIG. 3 illustrates a tissue carton dispenser according to another embodiment of the present disclosure;
[0012] FIG. 4 illustrates a cross-section of the embodiment of FIG. 3 taken at line 2 - 2 ; and
[0013] FIG. 5 illustrates one embodiment for manufacturing a compressed tissue stack.
DEFINITIONS
[0014] It should be noted that, when employed in the present disclosure, the terms “comprises,” “comprising,” and other derivatives from the root term “comprise” are intended to be open-ended terms that specify the presence of any stated features, elements, integers, steps, or components, and are not intended to preclude the presence or addition of one or more other features, elements, integers, steps, components, or groups thereof.
[0015] As used herein, “tissue” generally refers to various paper products, such as facial tissue, bath tissue, paper towels, napkins, and the like. Normally, the basis weight of a tissue product of the present disclosure is less than about 80 grams per square meter (gsm), in some embodiments less than about 60 gsm, and in some embodiments, between about 10 to about 60 gsm.
[0016] As used herein the term “carton opening” generally refers to an opening formed in one or more walls of a carton.
[0017] As used herein the term “dispensing opening” generally refers to an opening through which tissues are dispensed such as, for example, an opening formed in a material covering a portion of the carton opening.
DETAILED DESCRIPTION
[0018] Generally, the present disclosure relates to a carton for dispensing compressed tissues. By enlarging the size of the dispensing opening, it has been discovered that the compressed tissues may be dispensed with ease. In addition, by extending the dispensing window along at least one of the sidewalls of the carton, dispensing of the compressed tissues may be improved. Thus, the carton of the present disclosure provides dispensing comparable to non-compressed tissue containers, while providing tissues in a compressed or concentrated product form that requires less shelf space.
[0019] Now with reference to FIG. 1 which illustrates one embodiment of a compressed tissue carton of the present disclosure in a form suitable for shipping. As shown in FIG. 1 , the carton 10 comprises a top panel 20 , first 50 and second (not shown) sidewalls, opposing first 54 and second (not shown) end panels, a bottom panel (not shown), a carton opening 30 , and a surfboard 25 covering at least a portion of the dispensing opening. The surfboard
may be present on the top panel 20 (such as represented by the rectangular perforation in FIG. 1 ). Such surfboards are a common feature of current commercially available tissue cartons. In certain embodiments the surfboard may be attached to a cut out section in the dispensing window to allow for a larger dispensing opening. In certain embodiments, to further facilitate dispensing of the first sheet, the surfboard may be attached to the top sheet of the tissue stack such that when the surfboard is removed by a user the top sheet is dispensed. As further illustrated in FIG. 1 the surfboard 25 may also comprises a finger tab 27 to facilitate removal by a user.
[0021] The carton may be constructed from any rigid materials, for example, cardboard, carton stock, paper board, polypropylene, polyethylene, polystyrene, ABS plastic, plastic, metal, wood, and glass amongst other suitable alternatives.
[0022] With reference to FIG. 2 , which is a cross-section of the carton of FIG. 1 along the line 1 - 1 , the stack of compressed folded tissue sheets 60 is constrained within the carton and prevented from expanding into the carton opening by the surfboard 25 . During manufacturing, the stack of tissues can be separately compressed and inserted into the cartons, such as by inserting the compressed stack or clip of tissues into an open end of a carton. This is easily accomplished with sealable end flaps on the upper and lower portions of the carton as are commonly used to load partially-assembled tissue cartons with uncompressed tissue clips or stacks. In such cases, the height of the carton (H) is preferably slightly greater than the compressed height (h 3 , defined below) of the tissue stack. The height of the carton (H) is measured between the inside surface of the top face of the carton and the inside surface of the opposing bottom face of the carton.
[0023] The initial heights of the compressed tissue stack (h 3 ) and the carton (H) may vary depending upon the number of sheets within the stack, the caliper of the individual sheets and the nature of the folding of the sheets. In general, the height of the un-compressed stack (h 1 , discussed further below) will be from about 140 to about 220 percent of the height of the carton (H), more specifically from about 160 to about 200 percent of H, and still more specifically from about 170 to about 190 percent of H. In the compressed state, h 3 will be approximately equal to H or slightly less, for example from about 90 to 100 percent of H. Suitably, h 3 is from about 95 to about 100 percent of the height H, more specifically from about 97 to about 100 percent of H.
[0024] FIG. 3 schematically illustrates the product of FIG. 1 after the user has removed the surfboard and the compressed stack of tissues has been allowed to vertically expand for dispensing the first tissue. As shown in FIG. 3 , the carton 10 comprises a top panel 20 , first 50 and second (not shown) sidewalls, a carton opening 30 , a dispensing window 35 covering at least a portion of the carton opening 30 and a dispensing opening 40 disposed on the carton opening 30 , through which the tissues 60 are dispensed. The carton 10 is preferably designed such that the carton opening 30 allows the compressed clip to decompress and expand into the opening created by the user, easing dispensing.
[0025] The relatively large surface are of the carton opening 30 , relative to the top panel 20 , effectively provides an area for the compressed stack of tissues to expand into when the compression of the tissues within the carton is released by removal of the surfboard. Under this condition, the expanded stack of tissues has raised the flexible dispensing window, effectively increasing the volume of the carton. In a particularly preferred embodiment, upon release of the surfboard by a user the compressed tissue stack expands from a compressed height (h 3 ) to a dispensing height (h 4 ), where the dispensing height (h 4 ) is from about 100 percent to about 150 percent greater than h 3 . As used herein, the dispensing height (h 4 ) refers to the maximum height of the tissue stack measured after the surfboard is removed and before the first tissue dispensed. In should be noted however, that while it is preferable that the stack height expand with the release of the package compression, it is not a requirement of this invention. Therefore, in certain embodiments h 3 may equal h 4 .
[0026] In those embodiments where the dispensing height (h 4 ) is greater than the height of the compressed tissue stack (h 3 ), the carton may be configured such that the total volume of the carton, and not just the stack height of the tissue stack, increases when the carton is opened. The volume of the carton generally increases as a result of the flexible dispensing window material expanding in response to pressure exerted by the stack of tissues. Thus, in certain embodiments the carton may have a volume (V 1 ) prior to removal of the surfboard and dispensing of the first tissue and second volume (V 2 ) upon removal of the surfboard and dispensing of the first tissue, such that V 2 is 0.1 to 5 percent greater than V 1 and more preferably from 0.5 to 3 percent greater than V 1 .
[0027] According, in particularly preferred embodiments, the volume of the carton necessary to achieve satisfactory dispensing may be provided by a relatively large carton opening relative to the top panel of the carton. Thus, in one embodiment, the area of the opening 30 preferably comprises at least about 50 percent of the total area of the top panel 20 . In a particularly preferred embodiment the area of the carton opening 30 comprises from about 50 percent to about 85 percent and still more preferably from about 55 percent to about 70 percent of the total area of the top panel 20 . Accordingly, with reference to FIG. 2 , in certain preferred embodiments the carton opening 30 is substantially rectangular and has a width (w) and a length (l), while the top panel is also substantially rectangular and has a width (W) and a length (L). In certain embodiments the width (w) of the carton opening 30 may be from about 70 to about 100 mm and the length (l) may be from about 170 to about 200 mm, while the width (W) of the top panel 20 may be from about 100 to about 130 mm and the length (L) may be from about 195 to about 235 mm.
[0028] Preferably the carton opening 30 is covered, at least in part, by a dispensing window 35 . The dispensing window 35 may be selected from a moisture impervious material and more preferably from a flexible moisture impervious material that can bend or flex with minimal applied forces. Suitable flexible materials can include paper, polyethylene, polyester, polypropylene, polyvinyl chloride, polyamide, acetate, cellophane, rubber, elastomeric materials, or metal foils, amongst other suitable alternatives. The dispensing window can be a single layer, or a laminate of the above materials.
[0029] As illustrated in FIG. 4 the dispensing window 35 preferably extends beyond the interior surface of the top panel 20 to the sidewalls 50 , 52 . In a particularly preferred embodiment the dispensing window 35 extends the entire height of the sidewalls 50 , 52 . In other embodiments the dispensing window 35 may extend beyond the sidewalls 50 , 52 to the bottom panel 80 . The dispensing window may be attached to the top panel, one or more sidewalls, or the bottom panel, or any combination thereof.
[0030] As further illustrated in FIG. 4 , the tissue 60 is dispensed through a dispensing opening 40 . The dispensing opening 40 may be a simple slit in the dispensing window 35 that allows a user to access the upper most tissue in the stack. In a preferred embodiment the shape of the dispensing opening 40 is optimized to facilitate dispensing of the compressed tissues. Accordingly, in a preferred embodiment the dispensing opening 40 has a length that is about 45 to 85 percent, and more preferably about 60 to 75 percent, the length of the carton opening (l). In other embodiments the width of the dispensing opening 40 is from about 1 to about 30 mm and more preferably from about 10 to about 20 mm. Where the dispensing opening 40 has both length and width dimensions, the ends of the opening may be curved to further facilitate dispensing. In such embodiments the ends may have a radius from about 2 to about 20 mm and more preferably from about 5 to about 12 mm.
[0031] It must be noted that while the general shape of the carton 10 can be rectangular as shown; other shapes can also be employed, such as hexagonal, triangular, square and the like. Similarly, while the general shape of the top panel 20 and carton opening 30 is illustrated as rectangular, other shapes can also be employed, such as square, oval, and the like. In such cases, all that is required is that the area of the opening comprises at least about 50 percent of the total area of the top panel 20 .
[0032] Accordingly, the top and bottom sidewalls of the carton can be any shape or size. Suitable shapes can include triangular, square, rectangular, pentagon, hexagon, octagon, oval, circular, star shaped or fluted. The overall size of the carton and the shape of the sidewalls can be designed as needed to properly dispense the sheet material placed within the carton. The size and shape of the carton can be influenced by the size of the sheet material being dispensed, how the sheets are folded prior to placement in the dispenser, the number of sheets placed into the dispenser, the orientation of the stack, configuration of the stack within the dispenser, and the characteristics of the material being dispensed. Often more than one acceptable shape will work to properly dispense the sheet material.
[0033] In one embodiment, the top panel and bottom panel comprised rectangles having an approximate size of 21.5 cm long by 11.5 cm wide. The sidewalls in this embodiment comprise two pairs of opposing panels attached to the top and bottom panels as illustrated in FIG. 1 . The pair of opposing sidewalls have a height of approximately 3.5 cm and a length of approximately 21.5 cm. The other pair of opposing sidewalls, also referred to as end panels, comprise panels having a height of approximately 3.5 cm and a length of approximately 11.5 cm. Such a size is useful for dispensing standard size facial tissue sheets in a flat carton when folded into a stack and placed within the dispenser. The initial height of the dispenser was approximately 3.5 cm and the final height was approximately 4.2 cm, measured at its highest point, after the surfboard is removed and the carton is prepared for dispensing. With the top and bottom portions attached together, the dispenser comprised a rectangular box.
[0034] The stack of tissues may be interfolded, prefolded interfolded, or non-interfolded. As used herein, the phrase “prefolded interfolded” or “interfolded” tissues means that the tissues are folded and interleaved with neighboring tissues immediately above and/or below in the clip of tissues. The tissues can be interleaved by any suitable means, including the use of an interfolder as employed in the papermaking arts. If an interfolder is used, consecutive tissues may be attached to each other at perforation lines. In such cases, the unperforated segments of the perforation lines should be sufficiently weak to permit the consecutive tissues to separate from each other upon removal from the carton. This can be controlled by the degree of perforation of the tissue sheet. Tissues that may be employed in a non-interfolded clip which are not interleaved with neighboring tissues are releasably attached to neighboring tissues so that upon dispensing one tissue, the next adjacent tissue is ready for dispensing. Particularly preferred folding patterns include interfolding patterns that provide somewhat less friction, which tend to avoid tearing of the tissue when extracted from the container.
[0035] Webs or sheets may be folded in a stacked arrangement. Each web or sheet, when laid flat, may assume a square or rectangular shape, in many instances. Many different folds may be employed, and several embodiments of the invention are shown in the attached Figures. Folds are defined as first folds, second folds, third folds, and the like by reference to their respective position on the sheet. That is, a sheet or web having four folds, for example, typically would have a first fold, second fold, third fold, and fourth fold in that order, respectively, as when moving from one edge of the sheet to the opposite edge of that sheet.
[0036] A folded sheet, for example, would have four panels or folds and three creases. One crease appears at the junction of each fold. For example, a first crease is at the junction of the first fold and a second fold, as will be further described below. A bifolded sheet, for example, would have two folded panels and one crease, while a trifolded sheet would have three folded panels and two creases.
[0037] It should be understood that the term “web,” as used herein, is meant to include a sheet material made of one or more plies of material so that a multiple-ply sheet material is considered to be a “web” of sheet material, regardless of the number of plies.
[0038] As shown in FIG. 5 , the stack of folded tissues has an initial non-compressed height (h 1 ). The stack is subjected to a compressive force, for example, by a continuous rotating belt (illustrated in FIG. 5 ) or by other means known in the art. The compressive force compresses the stack, reducing its height to a compressed height (h 2 ). The compressive force is then removed, allowing the stack to return to the memory compressed height (h 3 ). Preferably the compressive force is controlled so that when the user opens the carton, the stack of folded tissues is not compressed or not significantly compressed to the extent dispensing of the tissues is adversely affected.
[0039] In certain embodiments the non-compressed height (h 1 ) of the stack may be, for example, from about 45 to about 95 mm. The compressive force preferably reduces the height of the stack by about 70 to about 85 percent, such that the compressed height (h 2 ) is from about from about 1 to about 3 cm. After the compressive force is removed the stack may decompress, regaining some of its original height, such that the memory compressed height (h 3 ) is from about 30 to about 60 percent less than the non-compressed height (h 1 ). Accordingly, in certain preferred embodiments the height of the memory compressed height (h 3 ), which is loaded into the carton, may be from about 30 to about 50 mm.
[0040] Likewise, the memory compressed stack height (h 3 ) can be expressed in terms of the difference between the original uncompressed stack height (h 1 ) and the compressed stack height (h 3 ), such that h 1 =h 3 +β(h 3 −h 2 ), where β is the recovery coefficient of the stack of tissue sheets. Thus β can be from about 0 to about 1.5, more preferably from about 0.2 to about 1, and still more preferably from about 0.3 to about 1.
Example
[0041] In order to further illustrate the invention, a tissue carton, similar to the carton illustrated in FIG. 1 , having a top panel, first and second sidewalls, opposing first and second end panels, a bottom panel, a dispensing opening, and a surfboard covering a portion of the carton opening was constructed. The dimensions of the carton were as follows: height (H) 35 mm, length (L) 215 mm, width (W) 115 mm, carton opening length (l) 180 mm, and carton opening width (w) 10 mm. The carton opening was covered by a dispensing window having a dispensing opening that measured 115 mm in length and 12 mm in width and had rounded ends having a radius of 8 mm. The area of the carton opening relative to the top panel was 155.94 to 247.25 cm 2 , or 57 percent of the area of the top panel. A comparison of the dimensions of other tissue cartons is found in the table below.
[0000]
TABLE 1
Total
Top
Carton
Opening
Sheet
Carton
Panel
opening
Area:
Sheet
Area
Volume
Area
Area
Top Panel
Product
Count
(cm 2 )
(cm 3 )
(cm 2 )
(cm 2 )
Area
Example 1
88
210276
865
247.25
155.94
57%
Kleenex ™
56
70560
1344
112
34.9
20%
Cube
Kleenex ™
88
110880
1825.05
264.5
76.58
9%
Original
Kleenex ™
100
159300
2746
499.2
149.41
30%
Mansize
Sainsbury's
150
126000
1912
265.5
128.33
48%
Basics
Facial Tissue
Morrison's
150
126000
1765
248.64
65.60
22%
Regular
Morrison's
56
128967
2417
503.48
181.43
36%
Mansize
Morrison's
90
151200
2188
248.64
56.94
2%
The Best
Family
Tissue
Puffs ®
124
109874
2511
270
106.26
44%
Ultra Soft &
Strong
Great
110
97469
1890
270
96.25
36%
Value ™
Facial Tissue
[0042] The tissue carton was loaded with a compressed stack of 88 sheets of three ply tissue measuring 247.25 cm 2 . The total sheet area (i.e., area of a tissue sheet multiplied by the number of sheets multiplied by the number of plies) was 210276 cm 2 . The 88 sheets had an uncompressed height (h 1 ) of 6.5 cm. The stack was compressed by 78 percent to a height (h 2 ) of 1.4 cm. The compressive force was then removed and the stack was allowed to decompress to a memory compressed height (h 3 ) of 3.2 cm. The compressed clip, having a height of 3.2 cm, was then loaded into the carton.
[0043] The surfboard was removed from the top of the dispensing carton in order to dispense the tissues. Despite the stack of tissues being compressed dispensing was achieved without tearing the tissues.
[0044] A carton volume reduction of approximately 53 percent was achieved compared to traditional cartons used to dispense similar sized non-compressed tissue. Cardboard packaging required was reduced by 28 percent. As a result, the cost savings associated with the material and shipping costs for such a product would be significant.
[0045] It will be appreciated that the foregoing example, given for purposes of illustration, is not to be construed as limiting the scope of the invention, which is defined by the following claims and all equivalents thereto. | Generally, the present disclosure relates to a carton for dispensing compressed tissue sheets comprising a carton having an oversized carton opening and a compressed stack of tissues, such as facial tissues. The compressed carton can significantly reduce costs associated with shipping such low density products. The oversized carton opening permits the compressed stack of tissues to expand, releasing the compression of the tissue stack and allowing the tissues to be dispensed normally. | 1 |
BACKGROUND OF THE INVENTION
The present invention relates to a method of electroplating and to an electroplating device adapted to produce a flow of an electrolyte past a conductive component to be coated, the electrolyte containing dissolved salts of a metal for electrolytic deposition on the component, which forms the cathode of an electrolytic cell of the device.
Use is already made of devices for treating unit components, where the component to be plated moves relative to the electolyte (e.g. in the case of nickel-plating). In the case of hard chromium plating, however, it is normal to use a stationary bath of electrolyte and there are no known devices for high-speed hard-chromium plating in a moving electrolytic bath and suitable for coating components in mass production on an industrial scale. There is thus a gap in the existing technology which the present invention aims to fill.
SUMMARY OF THE INVENTION
The invention provides an electroplating device comprising: at least one electrolytic cell containing a tubular anode and having inlet and outlet connections for a bath of electrolyte flowing longitudinally through the anode; and a removable component-holder comprising means for gripping a component to be electroplated and electrically co-operating with a cathode-supply plate and mounting and centring means on the cell for closing the cell and suspending the component along the axis of the anode.
Preferably, the electroplating device comprises at least one row of a plurality of cells mounted on common suspending means for suspending the cells immersed in a single common tank of electrolyte. The suspending means may inter alia comprise two half-plates for mounting the anodes in their respective cells and holding therebetween a plate for supplying electricity to the anodes.
According to another preferred feature of the invention, in a device comprising at least one row of cells, the associated component-holders of the row are held together by two half-plates which grip between them the aforementioned cathode-supply plate, which is common to the various component-holders associated with the row of cells.
According to a further preferred feature, the device may comprise an electrolyte-distributing grid secured to the anode in the path of electrolyte flowing through the anode.
The device according to the invention can be used for electrolytic deposition in a flow of electrolyte. It is particularly suitable for plating elongate components with hard chromium. Compared with conventional electroplating devices, it enables the current densities to be very substantially increased without burning the deposit. This increase in current density results in a considerable improvement in the faradic output and a consequent reduction in waste energy consumed during the liberation of hydrogen. The reduction in metal fatigue caused by hydrogen is another result of the improvement in the faradic output. There is also a more uniform thickness of the deposit along the generatrices of the plated elongate components, and a very marked improvement in the resistance to corrosion.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be readily understood, an embodiment of an electroplating device according to the invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a top view of the device, showing the methd of joining a number of rows of cells;
FIG. 2 is a fragmentary view of the device of FIG. 1 in elevation, showing only the top parts of the cells;
FIG. 3 is a partly cut-away elevational view of a row of three cells, showing the fixed parts of the device; the movable parts, i.e. the cathodes and the associated bearing means, are shown in broken lines;
FIG. 4 is a top view of the cells in FIG. 3;
FIG. 5 shows one of the cells in FIG. 3 in longitudinal section in a vertical plane (V--V) perpendicular to the plane of FIG. 3;
FIG. 6 shows the cathode-bearing assembly, partly in section in a vertical plane; and
FIG. 7 shows the assembly of FIG. 6 in the position which it occupies over the cells during operation; the cross-sectional plane in FIG. 7 is perpendicular to the plane of FIG. 6 and identical with the plane of FIG. 5.
DESCRIPTION OF PREFERRED EMBODIMENT
In the particular case under consideration, a complete electroplating device embodying the invention comprises three rows each of three electrolytic cells 2. The nine cells 2 are suspended in a common tank 3, where they are partially immersed in an electrolytic bath 4 containing dissolved salts of the metal to be electro-deposited. The actual cells are secured in the tank whereas their covers are removable and also act as component-holders for cathodes constituting the components to be plated.
As shown in FIG. 2, which illustrates the main features of the assembly the three cells in each row are mounted on a common suspension plate 5 resting on the walls of tank 3. The electrical connections for supplying the anodes are also made to plate 5. The drawing shows, for example, connecting strips 6 for supplying anode current. The strips interconnect the rows of cells, as do connecting bars 20 which give mechanical strength to the assembly.
Above tank 3 the various cells are closed by component-holders 7 (FIG. 2) which are secured in groups of 3 by a support plate 8 to which electric connections are made for supplying the cathode. Once the component-holders have been secured in sealing-tight position on their respective cells, the various support plates 8 are interconnected at the sides of the tank, like plates 5, by strengthening bars 9 and by connecting strips 10 for supplying current.
The design of the cells is illustrated in greater detail in the illustration of a row of three cells in FIGS. 3 and 4 and in longitudinal section through an individual cell in FIG. 5.
Each cell comprises a cylindrical conical-bottomed vessel 11 which is open at its top, a cylindrical cap 12 being mounted on the end of the vessel. In order to ensure a flow of electrolyte through the cell longitudinally of the vessel, the vessel bottom has an input connection 13 for supplying electrolyte, whereas cap 12 has two diametrically opposite outlet connections 14 and 15.
Cap 12 as part of a tubular anode is secured to vessel 11 by two half-plates 16 and 17 bolted together and engaging collars on the vessel and cap respectively. The two half-plates together constitute the suspension plate 5 in FIG. 1 and 2, i.e. the plates 16 and 17 are elongate so as to be common to the three cells in the row, which are thus secured together. At their ends the plates 16 and 17 have eyelets 18 for ease in handling the row. At the bottom, the three cells are likewise interconnected by a cross-member 19 made up of two parts interconnected so as to grip the bottoms of the vessels in specially-provided cavities.
The interior of vessel 11 is lined by a cylindrical anode 21 having a collar 22 at its top end for holding the anode between the vessel 11 and cap 12. An annular seal 23 provides sealing between anode 21 and vessel 11 and an annular seal 24 provides sealing between anode 21 and cap 12. A perforated disc or grid 25 is secured to the bottom end of anode 21 across the flow of electrolyte so as to improve the distribution thereof.
A conductive plate 26 is gripped between collar 22 and the top surface of vessel 11 so as to supply electricity to the anode. In the cross-section of FIG. 5, plate 26 is shown enclosed in the cell walls, but in the longitudinal direction of the row of cells it extends through the walls and is common to the three cells. Beyond the end cells, it is enclosed between the two half-plates 16 and 17, from which electrical terminals 27, 28 project.
The row of cells also bears snap-fastener manipulating devices 29 having supports 31 secured to half-plates 16 and 17. Devices 29 are used for positioning and withdrawing the component-holders. They are equipped with pressure means 32 and jacks 33 pivoted to the snap-fasteners. The mechanisms are adapted to press the component-holders in sealing-tight position on the cells. An annular seal 34 is disposed in cap 12.
Referring now to FIGS. 6 and 7, the component-holders are grouped in threes like the corresponding cells. They are secured together by two half-plates 36 and 37 joined together by bolts 38. The half-plates co-operate to enclose a plate 39 in a corresponding recess in the bottom half-plate 36. Plate 39 supplies electricity to the cathodes and has terminals 41 (FIGS. 3-4) projecting from its ends. Eyelets 42 (FIG. 3) are used for manipulating the removable assembly.
The body 43 of each component-holder forms a cone for centring on the top aperture of the corresponding cell. It is secured under the common support means by three screws 44 which extend thrugh half-plate 36 and supply plate 39 and have heads which bear on plate 39 via insulating washers 45.
A shaft 46 slides in it a central hollow of body 43 and carries the three jaws of a gripping means 47 connected thereto by spring strips 48. When body 43 is in the bottom position (FIG. 6) the three jaws come out towards the exterior of body 43 in the grip-open position, whereas when body 43 is in the top position (FIG. 7) the jaws are retracted inside body 43 in the grip-closing position. The gripping means can thus suspend a component for electroplating, e.g. a rod 49 in FIG. 7, from the component-holder. Sealing-tightness in the closed position, for electrolytic treatment, is ensured by a seal 51 between body 43 and means 47 and a seal 52 between body 43 and shaft 46. A cavity is formed above the component-holder in the top half-plate 37 to receive shaft 46 in the open position.
An electrical connection between the component for electroplating and the supply plate 39 is made via shaft 46 and means 47, both made of conductive metal, in co-operation with a braided earth wire 53 having its ends secured in electrical contact with plate 39 and the top of shaft 46, and braided shunt wires 49 having their ends secured to the side of shaft 46 and in each jaw of means 47 respectively.
When the component-holder suspending rod 49 is brought, together with the removable assembly to which it belongs, above the corresponding stationary cell and fitted into it, rod 49 is automatically positioned along the cell axis, i.e. along the axis of the cylindrical anode 21.
During treatment, a flow of electrolyte is maintained by introducing the electrolyte under pressure at the bottom of the vessel and discharging it through an overflow into the tank. A forced flow is maintained by a pump outside the vessel.
By way of example, the aforementioned device can be used on an industrial scale for electroplating hard components such as shock-absorber rods with hard chromium. It can operate under the following conditions, in comparison with treatment in a stationary bath.
______________________________________ Stationary With flow bath______________________________________Bath, g/l CrO.sub.3 50 250 250 250 g/l H.sub.2 SO.sub.4 0.5 2.5 2.5 2.5Temperature (°C.) 70 50 70 50Current density, A/dm.sup.2 200 200 200 40Deposition rate, μm/h 240 360 190 33Output (%) 26 40 21 18______________________________________
It can be seen that, in the case of a given bath, there is an increased in the deposition rate and output compared with conventional conditions. The device, however, can also save material by using baths having a low concentration of chromic acid. Another advantage of the described embodiment is that relatively small-capacity tanks can be used for a given production rate.
Of course, however, the invention is in no way limited to the embodiment described in detail, but includes all variants falling within the spirit of the invention. | The invention relates to the plating of conductive components by electrolytic deposition.
An electroplating device in accordance with the invention comprises at least one electrolytic cell containing a tubular anode and having inlet and outlet connections for a bath of electrolyte flowing longitudinally through the anode. A removable component-holder of the device comprising means for gripping a component for plating, which component holder is electrically connected to a cathode-supply plate and is adapted to be mounted on the cell to close it and suspend the component along the axis of the anode.
The device can be used inter alia for plating with hard chromium. | 2 |
BACKGROUND OF THE INVENTION
This invention relates to an apparatus and method for automatically producing lip-synching between facial animation and a spoken sound track.
There are a number of existing techniques for synchronizing facial animation to a spoken sound track (which, as used herein, is intended to generically include any live or recorded acoustical or electrical representation of communicative sounds). In the common rotoscoping method, an actor saying the dialog is filmed, and the actor's mouth positions are copied onto the animated character. This, and other manual techniques, have the obvious disadvantage of high cost in labor and time.
In Pearce et al., "Speech And Expression: A Computer Solution To Face Animation", Proceedings, Graphics Interface, 1986, there is described an approach to synchronized speech in which a phonetic script is specified directly by the animator. The phonetic script is also input to a phoneme-to-speech synthesizer, thereby achieving synchronized speech. This approach is appropriate when the desired speech is specified in textual form, and the quality of rule-based synthetic speech is acceptable to the purpose. A drawback of this approach is that it is difficult to achieve natural rhythm and articulation when the speech timing and pitch is defined in a script or derived by a rule-based text-to-speech synthesizer. The prosody quality can be improved somewhat by adding information such as pitch and loudness indications to the script.
In the U.S. Pat. No. 3,662,374 of Harrison et al., there is disclosed a system for automatic generation of mouth display in response to sound. Speech sounds are filtered by banks of filters, and a network of potentiometers and summers are used to generate signals that automatically control mouth width and upper and lower lip movement of an animated mouth.
In the U.S. Pat. No. 4,260,229 of Bloomstein, there is disclosed a system wherein speech sounds are analyzed, digitally encoded, and transmitted to a data memory device that contains a program for producing visual images of lip movements corresponding to the speech sounds. In this patent it is stated that an actor speaks and his voice is encoded into a phoneme code which includes sixty-two phonemes (for the English language). Each phoneme is coded at a desired number of frequencies, three being specified as an example. A commercially available speech encoder is suggested for the job. A drawback of this system, however, is the need for such a sophisticated speech encoding capability, with its attendant cost and processing time.
The U.S. Pat. No. 4,600,281 of Bloomstein discloses a method for altering facial displays in cinematic works which does not use phonetic codes.
It is among the objects of the present invention to provide an improved automatic lip-synching apparatus and method which provides realistic representations of mouth movements, but without undue cost, complexity, or operating time requirements.
SUMMARY OF THE INVENTION
The present invention takes advantage of the fact that the speech information and processing needed for successful animation lip-synching is actually much less than the information and processing which is needed for identifying individual words, as in the traditional speech recognition task. The disclosed embodiment utilizes linear prediction (a well known technique, usually used for speech synthesis) to obtain speech parameters which can be used to identify phonemes from a limited set corresponding to visually distinctive mouth positions.
Linear prediction models a speech signal as a broadband excitation signal that is input to a linear autoregressive filter. This provides an abstracted but fairly accurate model of speech production, in which the filter models the vocal tract (mouth, tongue, and lip positions) and the excitation signal approximates the acoustic signal produced by the vocal cords. In the present invention, the latter portion (voicing) is removed from consideration; i.e., the pitch information is convolved out. The remaining information, pertaining to the vocal tract model is advantageously used in a limited matching process that would not be of much use in recognizing vocabulary words, but is sufficient to recognize the sounds associated with the basic visually distinctive mouth positions. [As used herein, the term "mouth position" is intended in a non-limiting sense to include the position, orientation or shape of the mouth, lips, tongue, and teeth.]
In accordance with an embodiment of the invention, there is set forth an apparatus for producing lip-synching for a spoken sound track. Means are provided for storing, for each of a number of mouth positions, an unvoiced phonetic information representation associated with a mouth position. Means, responsive to samples of sound from the sound track, are provided for generating unvoiced phonetic information signals for the samples. Further means are provided for comparing the unvoiced phonetic information signals with the stored unvoiced phonetic information representations to determine which of the stored representations most closely matches the unvoiced phonetic information signals. The determined representations are then stored in time correspondence with the sound track.
In a preferred embodiment of the invention, the means responsive to samples of sound is operative to generate the unvoiced phonetic information signals as linear predictive coding signals representative of a vocal tract filter.
Further features and advantages of the invention will become more readily apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is block diagram of an apparatus in accordance with an embodiment of the invention, and which, when suitably programmed, can be used to practise the method of the invention.
FIG. 2 is a flow diagram of a routine for programming the processor of FIG. 1 to implement the training mode an embodiment of the invention.
FIG. 3 is a flow diagram of a routine for programming the processor of FIG. 1 to implement the production mode of an embodiment of the invention.
FIG. 4 is a flow diagram of the comparison routine of the FIG. 3 flow diagram.
FIG. 5 is shows examples of visually distinctive mouth positions and sounds which result in the respective positions.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is shown a block diagram of an apparatus in accordance with an embodiment of the invention and which, when properly programmed, can be utilized to practise a method in accordance with the invention. A transducer, such as a microphone 10, receives input sounds and produces electrical signals that are representative of the received sounds. The microphone output is amplified by preamplifier 15, and filtered by low-pass filter 20 which, in the present embodiment, is low-pass at 5000 Hz. The output of filter 20 is coupled to analog-to-digital converter 25.
In the embodiment of FIG. 1, a processor 100 is provided, and is programmed, in a manner to be described, to control operation of other elements of the FIG. 1 embodiment, and to also perform various computations which are utilized in processing speech signals and selecting lip synch mouth positions for a control script. In an embodiment of the invention, the processor used was a model VAX-780, sold by Digital Equipment Corp. The processor 100 is typically provided with input/output means 101, which includes a keyboard and monitor, general storage 110 (including RAM and non-volatile storage), and clock circuitry 115. The embodiment of FIG. 1 also shows a data tablet 120 as a further input-generating device, and individual memories identified as audio storage buffer 125, audio disc storage 130, mouth position library 135, and lip-synch control script storage 140. The analog-to-digital converter 25 is coupled to processor 100 and to storage 125 and 130, and is also under control of processor 100. It will be understood that any suitable processor and peripherals can be utilized, consistent with the principles of the invention as set forth. The indicated separate memories facilitate understanding of operation of the invention, but the number, size, and type of memories employed is a matter of design choice.
In the present embodiment of the invention, a training mode is used to store, for each of number of visually distinctive mouth positions, an unvoiced phonetic information representation. Preferably, although not necessarily, the training utterances are spoken by the person who will be speaking on the sound track to be lip synched. In the present embodiment, eleven training utterances are used, and these correspond to eleven visually distinctive mouth positions. FIG. 5 shows an example of some of the characteristic mouth positions and the sounds which produce these positions. [These are available in standard "How To Read Lips" texts.] It will be understood, however, that the principles of the invention apply to any suitable number of mouth positions, and corresponding unvoiced phonetic features. Also, in the example of FIG. 1, the basic mouth positions are sketched by an animator (e.g., from viewing the mouth of the speaker, existing sketches, etc.), and stored in mouth position library 135. Alternatively, graphical representations of mouth positions, from any suitable source, can be stored before, during, or after the present procedure, and utilized when the lip-synching script is employed to compile the completed combination of video and sound track.
During the second mode of operation of the invention, called the "production mode", the sound track for which lip-synching is to be implemented is processed to obtain a lip-synch control script; i.e., in the present embodiment, a sequence of output indications, synchronized in time with the sound track timing, which indicate the mouth position information at each point of the sound track. It will be understood that if a sound track can be lip-synched quickly and efficiently, there is little further advantage to achieving the result in "real time". In the present embodiment, a sound track can be processed "on the fly", e.g. by using the indicated buffering, or a pre-recorded sound track can be processed at a convenient rate, depending upon the computational speed and memory of the computing system utilized and the need and desire for production speed. Thus, although one of the advantages of the invention resides in the efficiency and reduced complexity of processing, the invention does not depend upon the particular source or type (e.g. live, recorded, or mixed) of sound track to be lip-synched.
Referring to FIG. 2, there is shown a flow diagram of a routine for programming the processor 100 of FIG. 1 to implement an embodiment of the invention. The diamond 211 represents selection of the operational mode which is active; namely, the so-called "training" mode or the so-called "production" mode. If the production mode is active, the block 311 is entered (see FIG. 3 below). When the training mode is active, the block 212 is entered, this block representing the initiation of a training utterance index i. In the example of the present embodiment, eleven training utterances, corresponding to eleven visually distinctive mouth positions, are utilized, although any suitable number can be used. A prompt is displayed indicating the next training utterance to be spoken (block 215); i.e., one which has a central sound that characterizes the current mouth position. The energy level of the speech is then monitored (diamond 216), until it is determined that the training utterance has begun, whereupon a timer is started (block 217). The digitized speech (output of analog-to-digital converter 25 in FIG. 1, or previously recorded) is then stored, such as in buffer 125, and this continues until the energy of the received utterance falls below a predetermined threshold (diamond 222), whereupon storage is terminated (block 225) and the timer is stopped (block 226). The block 230 is then entered, this block representing the locating of the approximate center of the stored speech, which is determined from one-half the timer count. A group of digitized speech samples from the center of the utterance are then stored, as represented by the block 231. In the present embodiment the sampling rate of the analog-to-digital converter is 15 KHz, and there are 60 8-bit sample groups per second. Accordingly, each sample group has 250 samples. One approximately central group of 250 samples (as stored via block 231) is subsequently processed.
The next portion of the routine of FIG. 2 involves the analysis of the stored sample group to obtain a parameter set which represents the linear predictive coding ("LPC") coefficients for this group of speech samples, in the frequency domain. This processing, per se, is well known in the art, and is described, for example, in Markel and Gray, "Linear Prediction of Speech", Springer-Verlag, New York, 1986. Reference can also be made to the following U.S. Patents which describe LPC processing: U.S. Pat. Nos. 3,624,302, 4,038,495, 4,191,853, 4,070,709, 4,389,540, 4,544,919, and 4,661,915.
It will be understood that other suitable means can be utilized to obtain unvoiced phonetic characteristics. In FIG. 2, the block 235 represents the computation of LPC coefficients for the stored group of speech samples. In an embodiment hereof, a program called "AUTO" (Programs For Digital Signal Processing", IEEE Press, 1979) was utilized to obtain the LPC coefficients, as twelve 32-bit numbers. A processing chip, namely a Texas Instruments Model 320 DSP chip (illustrated in FIG. 1 as processing chip 190), was then utilized in obtaining a Z-transform, as represented in FIG. 2 by the block 240. In the embodiment hereof, the Z-transform produces a filter response characteristic in the frequency domain, and thirty-two points thereon are output as representing the unvoiced phonetic filter characteristic, as a function of frequency. Each of these points is set forth as a 32 bit number. Accordingly, after the processing indicated by blocks 235 and 240, the result is a numerical representation (thirty-two 32-bit numbers) which represent the unvoiced phonetic features of the reference utterance i that corresponds to a particular mouth position, i. This set of numbers, designated L i , is stored, as represented by the block 245. Inquiry is then made (diamond 250) as to whether the last training utterance has been processed. If not, the index i is incremented, and the block 215 is reentered, whereupon the loop 290 continues until a set of numbers L i , has been obtained for each of the training utterances.
Referring to FIG. 3, there is shown a flow diagram of the so-called "production" portion of the routine. The block 311 is entered (from diamond 211 of FIG. 2), this block representing the initiation of the index for the first group of sound track samples for the present production run; i.e., the beginning of the section of sound track that is to be processed to obtain output mouth positions. In the description of the flow diagram of FIG. 3, it is assumed that the low-pass filtered and digitized samples from the sound track have been stored in buffer memory 125 (or are being stored as processing proceeds) but, as noted above, the source or storage status of the sound track does not affect the principles of the invention. After the index is initiated (block 311), the group of samples identified by the index is retrieved from the buffer, as represented by the block 315. The LPC coefficients for the sample group are then computed (block 320), and the Z-transform is computed to obtain the numerical values for the unvoiced phonetic characteristic of the this group of samples. These computations are the same as those described above in conjunction with blocks 235 and 240, respectively, of FIG. 2. The resultant set of numbers for the current sample group, designated as L c , is stored (block 330), and a comparison routine (block 350) is then performed to determine the best match between L c and the stored unvoiced phonetic characteristic, L i , associated with each of the candidate mouth positions. The routine of block 350 is described in conjunction with FIG. 4. The result of the comparison, which is a selection of one of the eleven (in this embodiment) mouth positions, is then stored (block 355) in a control script (block 140, FIG. 1) in conjunction with the sound track timing information. Accordingly, each 1/60 second on the sound track control script will have a designation of a mouth position that is associated with that 1/60 second interval on the sound track. Inquiry is then made (diamond 360) as to whether the last sample group for this run has been processed. If not, the sound track sample group index is incremented (block 380), and the block 315 is again entered for retrieving of the sample group, and continuing of the loop 375 for processing of each sample group in this run.
Referring to FIG. 4, there is shown a flow diagram of the comparison routine represented by the block 330 of FIG. 3. The block 411 represents the initialization of the candidate index j, the initialization of the spectral parameter index h (i.e., the parameters defining the spectral LPC characteristic, as represented by the 32 numbers in the present embodiment), and the clearing of an accumulator. The block 45 is then entered, and for the candidate j (that is, the first of the eleven stored training word possibilities, in the present embodiment), the square of the difference is computed for the first spectral parameter h. The result is then added to the accumulator (block 417), and inquiry is made (diamond 420) as to whether the last h has been considered. If not, h is incremented (block 425), and the loop 428 is continued until the sum of squares of differences has been obtained (in the accumulator) for the first training sound candidate [which is also the first mouth position candidate]. The sum stored in the accumulator is stored as the sum of squares of differences, called S j (block 430). Inquiry is then made at (diamond 435) as to whether the last candidate has been considered. If not, the candidate index j is incremented and the accumulator is cleared (block 440). The loop 450 is candidate j. The smallest S j is then obtained and stored, as represented by block 460.
After obtainment of the control script (block 140, FIG. 1) standard computer graphics techniques can be utilized in compiling the lip-synched animation using the control script, the mouth position library (block 135, FIG. 1), and a source of animation on which the mouth positions are to be superimposed (block 195, FIG. 1).
The invention has been described with reference to a particular preferred embodiment, but variations within the spirit and scope of the invention will occur to those skilled in the art. For example, it will be understood that silence or low acoustic energy in the sound track will be routinely translated as a closed mouth position, and that sharp discontinuities in mouth position can be smoothed out. In this regard, it may be useful, for example, to retain the second best match candidate mouth position, and the matching scores of the first and second best matches, so that the second best match would be considered in the event of an unnatural seeming sharp discontinuity of mouth position. Also, it will be understood that a speech synthesizer can be used, if desired, to synthesize the sound track from the LPC information, although this is not preferred. Finally, it will be recognized that the frequencies and sampling rates and groups set forth are exemplary, and are not intended in a limiting sense. A degree of trade-off between processing complexity and accuracy will be apparent. | The disclosed invention takes advantage of the fact that the speech information and processing needed for successful animation lip-synching is actually much less than the information and processing which is needed for identifying individual words, as in the traditional speech recognition task, The disclosed embodiment utilizes linear prediction to obtain speech parameters which can be used to identify phonemes from a limited set corresponding to visually distinctive mouth positions. In the disclosed embodiment there is set forth an apparatus for producing lip-synching for a spoken sound track. Means are provided for storing, for each of a number of mouth positions, an unvoiced phonetic information representation associated with a mouth position. Means, responsive to samples of sound from the sound track, are provided for generating unvoiced phonetic information signals for the samples. Further means are provided for comparing the unvoiced phonetic information signals with the stored unvoiced phonetic information representations to determine which of the stored representations most closely matches the unvoiced phonetic information signals. The determined representations are then stored in time correspondence with the sound track. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to filter systems for removing particulate solids from an air stream, and in particular to filter systems for continuously removing resinated wood particles and fibers from an air stream.
2. Description of the Related Art
Filter systems used for continuously removing small particulate solids, such as wood particles and fibers, from an air stream include cyclone separators, bag house filter systems, and porous static filter elements. Each of these types of system has its advantages and disadvantages. Cyclone separators are simple and inexpensive to build, install and maintain. Cyclones' main utility is to separate a single fluid stream having entrained particles over a range of sizes into two or more air streams, namely an underflow stream containing the particles over a predetermined size, and an overflow stream containing the particles under a predetermined size. Cyclones are limited however in their ability to separate very small sized particles from an air stream. Therefore if the cyclone overflow stream is to be discharged to the environment, further treatment to remove a portion of the small particles from the cyclone overflow stream may be required.
Bag houses on the other hand are generally very effective at removing a high percentage of entrained particles down to a very small size from an air stream. Unfortunately, bag house systems capable of filtering large volume air streams are large, complex, and involve high maintenance costs. The primary reason that bag house filter systems are relatively large is that they are designed to separate the solids from the air stream by reducing the velocity of the air stream to approximately 1-3 feet per minute as the air stream passes through the bag element. As a result, a relatively large surface area is required, and may require a thousand or more large bags in some industrial applications. These bags must be connected by a piping system to deliver the air stream to them, and require frequent attention to keep the operating satisfactorily.
Additional difficulties may arise with bag house filtering systems if the solids to be separated are tacky or sticky. Solids which are not free flowing can plug the air distribution system or the bags themselves. Bag house systems are also very susceptible to fire caused by static charges in the vicinity of oxygen containing air carrying finely divided entrained solids. If the solids contain additional flammable materials, such as hydrocarbon resins, the fire danger is further aggravated. The cost of a bag house system is therefore extremely high, and such a system may not be able to provide safe and continuous operation.
Flat filter elements are also well-known means for continuously removing small particulate solids from an air stream, but their use on an industrial has not always proven acceptable, especially in the removal of sticky resinated particles mentioned above. Problems associated with flat filter elements include designing a filter element having sufficient porosity for maintaining a satisfactory flow rate while at the same time removing small particles. In the case of sticky particles, this problem is particularly difficult to solve. In addition, as solids accumulate and compact on a flat filter element, the throughput of the element is decreased further. If the pores of the filter are enlarged to increase air flow through the element, the small entrained particles are not satisfactorily retained on the filter element.
A need therefore remains for a compact, relatively inexpensive filter system for removing small particles from a relatively high-volume air stream, and which will continuously remove small and relatively sticky particles, such as resinated wood particles, from the air stream.
SUMMARY
The present invention meets the need for a compact, relatively inexpensive filter system for removing small particles from a relatively high-volume air stream, and which will continuously remove small and relatively sticky particles, such as resinated wood particles, from the air stream. The present invention is embodied in a filter system comprising means defining an air stream inlet for receiving an air stream containing ligno-cellulosic particles and fibers, means for directing said air stream along a predetermined path, said air stream flowing in a generally upward direction along at least a portion of said path, a filter assembly disposed in said path for removing said particles and fibers from said upwardly flowing air stream.
The filter assembly comprises one or more non-horizontal, foraminous filter elements and a foraminous filtering layer comprising said ligno-cellulosic particles and fibers formed on each filter element, the filters layer having a minimum porosity sufficient to allow said air stream to pass therethrough. Each filter element, which may comprise a screen, and preferably a 6-mesh screen, has openings which are sized to allow the airstream to pass through while retaining a portion of the particles and fibers on said filter element for forming a foraminous filtering layer in situ. the plurality of filter elements are preferably arranged in a generally sawtooth pattern.
The filter system and process further comprise means for maintaining the minimum filter layer porosity, preferably by intermittently reducing the thickness of said filter layer by removing a portion thereof. A portion of the filtering layer may be removed by intermittently vibrating said filter assembly with an impulse vibrator. Said filter layer removal means may be activated in response to a predetermined pressure drop across said filter assembly, or may be activated at predetermined time intervals.
A filter system according to the present invention may further comprise means for collecting and removing said collected filter layer portions from said filter assembly. The collecting means preferably comprises a hopper below said filter elements into which said solids fall under the influence of gravity. An auger assembly may be provided for receiving the collected solids and conveying them out of the filter system for disposal.
The present invention also provides a method for removing ligno-cellulosic particles and fibers from an air stream comprising the steps of introducing an air stream containing entrained particulates into a filter system as just described above, introducing the air stream containing ligno-cellulosic particles and fibers into said air inlet and passing said air stream through said filter element, retaining said first portion of particles and fibers on said filter element, thereby forming a foraminous filtering layer of said particles and fibers having a minimum porosity sufficient to allow said air stream to pass therethrough, retaining a second portion of said particles and fibers on said filtering layer, and discharging a filtered air stream from said filter system. The method preferably includes said air stream containing entrained solids being passed through said filter element at a velocity greater than 20 feet per minute.
The method comprises the step of maintaining said minimum filtering layer porosity, preferably by intermittently reducing the thickness of said filter layer by removing a portion thereof, preferably by intermittently vibrating said filter assembly. The method may include the step of reducing the thickness of said filter layer by removing a portion thereof. The step may be initiated in response to a predetermined pressure drop across the filter assembly, or at a predetermined time interval.
The method preferably removes more than approximately 90% of said entrained solids from said air stream containing entrained solids. The method preferably discharges less than about 2 pounds per hour of entrained solids to the surrounding environment.
These and other features of the present invention will be described with reference to the figures and the description of the preferred embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a side view of a filter system according to the present invention.
FIG. 2 shows an end view of a filter system according to the present invention.
FIG. 3 shows an end cross-sectional view of a filter system according to the present invention.
FIG. 4 shows a side cross-sectional view of a filter system according to the present invention.
FIG. 5 shows a top view of a filter element assembly according to the present invention.
FIG. 6 shows a side view of a filter element assembly according to the present invention.
FIG. 7 shows a cross-sectional side view of a filter element assembly including the screen vibrator assembly.
FIG. 8 shows a detail view of the filter element center support attachment to the side wall of the filter system.
FIG. 9 shows an end cross-sectional view of the filter element assembly upper end and top support.
FIG. 10 shows a center cross-sectional view of the filter element assembly upper end and top support.
FIG. 11 shows an end cross-sectional view of the filter element assembly lower end and bottom support.
FIG. 12 shows a center cross-sectional view of the filter element assembly lower end and bottom support.
FIG. 13 is a schematic view of the filter system compressed air supply piping system.
FIG. 14 is a schematic view showing the operation of the filter element assembly at initiation of the filtering operation.
FIG. 15 is a schematic view showing the operation of the filter element assembly after the filtering layer has been formed.
FIG. 16 is a schematic view showing the operation of the filter element assembly immediately prior to operation of the impulse vibrator.
FIG. 17 is a schematic view showing the operation of the filter element assembly immediately after to operation of the impulse vibrator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning to FIGS. 1, 2 and 3, a filter system according to the present invention is shown generally at 10. In the preferred embodiment, a pair of filter systems 10 are installed on a common supporting frame 12. Filter system 10 includes four main subassemblies, vent section 16, filter section 18, plenum 13, and hopper 15, which are placed one atop the other as shown in FIG. 1. Vent section 16 and filter section 18 each include an enclosed inlet guide, 17 and 19 respectively, which together with inlet 14, receive the incoming air stream and 21 and guide it into plenum 13 below filter section 18. Air stream 21 then passes upwardly through filter section 18 and exits filter system 10 through outlet 30 in vent section 16.
As air stream 21 passes through filter section 18, entrained wood particles and fibers are removed by filter assembly 32 as described below, and collected in hopper 15. As best seen in FIGS. 2 and 3, hopper sidewalls 34 taper inwardly from top to bottom, directing the separated wood particles and fibers through hopper bottom opening 36, into housing 37 of auger assembly 38. Auger 40 is located within auger housing 37, and is driven by 2-3 hp electric auger drive motor (not shown). Auger 40 is preferably operated continuously to move the collected particles and fibers toward auger discharge 44, through which they are discharged from filter system 10 through discharge chute 46 into bin 48. Auger discharge 44 is preferably fitted with a discharge valve 50 to allow operation of filter system 10 for brief periods without the need to continuously discharge separated particles and fibers from hopper 15.
As mentioned above, air stream 21 is directed through plenum 13 and filter section 18 for removal of entrained solids. Plenum 13 is a hollow enclosure 36 feet long by 12 feet wide by 41/2 feet high, and preferably is made from 10 gauge mild steel plate. Plenum 13 serves to receive air stream 21 from inlet guide 19 and distribute air stream 13 evenly into filter section 18. By use of plenum 13, the air pressure, and therefore the air flow, through filter section 18 is equalized along its length. Turning now to FIGS. 3-12, the operation of filter section 18 will be described in greater detail.
As best seen in FIG. 3, filter section 18 includes hollow filter housing 51 which is 36 feet long by 12 feet wide by 9 feet high, made form 10 gauge steel plate, and which is open at its top and bottom. Partition 52 extends vertically downward between its side walls 55 near one end to form inlet guide 19. Partition 52 preferably is curved inwardly near its bottom end to smooth the flow of air stream 21 as it changes direction entering plenum 13. Filter assembly 32 is disposed lengthwise within filter housing 51 lengthwise between partition 52 and end wall 54. Filter assembly 32 preferably consists of fifteen generally flat filter element assemblies 56 disposed angularly in a saw tooth pattern as shown in FIGS. 3 and 5. As shown in FIG. 5, the top ends 58 and bottom ends 60 of adjacent filter element assemblies 56 preferably share a common support 62 and 64 respectively. Top and bottom supports 62 and 64 are preferably 4" ID, schedule 113 steel pipe, which are supported at 48" intervals respectively by being welded or otherwise permanently attached at each end to filter housing side walls 55.
Referring now to FIGS. 4, 5 and 6, each filter element assembly 56 is assembled in place within filter housing 51 as follows. A pair of 6 foot wide, elongated filter screens 66 and 68 are each attached by one end to support 62 side-by-side. Filter screens 66 and 68 are preferably 6 mesh, 0.035 wire 304 stainless steel screen cloth 72" wide as manufactured by Cleveland Wire Cloth and Manufacturing. Screens 66 and 68 are then threaded in parallel around bottom and top supports 64 and 62 (FIGS. 1, 5) to form a series of flat screen sections 69 in a saw-tooth pattern as shown in FIG. 1. After being pulled taut, the free end of each of screens 66 and 68 is attached to end support 70. Screens 66 and 68 should be sufficiently taut to allow the screens to "bow" approximately 3" in operation as described below.
With screens 66 and 68 in place, a supporting framework for each flat screen section 69 is assembled as follows. Referring to FIGS. 4, 6, 10 and 12, upper and lower center stiffeners 72 and 74 are mounted between supports 62 and 64 on opposite sides of each flat screen section 69 along its longitudinal center line, overlapping and sandwiching the adjacent center edges of screens 66 and 68 to connect them together. (FIGS. 4, 6). Stiffeners 72 and 73, preferably made from 3" wide 10 gauge 304 stainless steel, are then riveted together with 1/4"×0.339" stainless steel rivets 74 at 6" intervals. As best seen in FIGS. 5 and 12, upper stiffener 72 is bent at its lower end and riveted to bottom support 64. Upper stiffener 72 is bent at its upper end as shown to accommodate the normal operational flexing of filter element 56 as described below without damaging screens 66 and 68. Referring to FIGS. 5 and 10, lower stiffener 74 is bent at its upper end and riveted to top support 62, and is bent at its lower end as shown to avoid damage to screens 66 and 68 during normal operational flexing.
Referring now to FIGS. 4, 6, 9 and 11, upper and lower edge retainers 76 and 78, preferably made from 11/2" wide 10 gauge 304 stainless steel, are fitted to the outer longitudinal edges of flat screen section 69 and connected to filter housing side walls 55 by means of rubber mounting strip 80 as follows. As best seen in FIGS. 6 and 9, upper pipe saddle 82 is welded onto side wall 55 beneath top support 62, with saddle side walls 86 and saddle bottom wall 88 extending outwardly away from filter housing side wall 55. Lower pipe saddle 86 as shown in FIG. 11 is bolted onto side wall 55 beneath bottom support 64, with side edges 89 and upper edge 90 extending outwardly from side wall 55. Upper and lower pipe saddles 82 and 86 are preferably made from 10 gauge 304 stainless steel. Upper edge retainer 76 is placed atop the outer edge of fiat screen section 69, extending from adjacent to bottom support 64 and overlapping upper pipe saddle 82 as shown in FIG. 9. Rubber mounting strip 80, a 5" wide strip of nitrile rubber, and lower edge retainer 78 are then placed on the opposite face of the outer longitudinal edge of screen section 69 (FIGS. 6, 9). Upper edge retainer 76 is bolted to upper pipe saddle 82, and upper and lower edge retainers 76 and 78 are bolted together, sandwiching the screen edge and rubber mounting strip 80 between them. The inward edges of rubber mounting strip 80 and upper and lower edge retainers 76 and 78 are generally aligned, while rubber mounting strip 80 extends outwardly from between upper and lower edge retainers toward filter housing side wall 55. As best shown in FIG. 7, rubber mounting strip 80 is bent 90° along its length, and its bent portion is bolted flat against side wall 55.
Upper and lower lateral screen stiffeners 92a and 92b are then placed across screen section 69 on opposite sides at a point slightly above center (FIGS. 4, 8), and riveted together along their length. Lateral screen stiffeners are attached at their ends to filter housing side walls 55 by being bolted to spring mounts 94 (FIG. 8). Each spring mount 94 is, a strip of 3" wide 10 gauge 304 stainless steel, having its upper end bent outwardly 90° and bolted to filter housing side wall 55, and having its lower end bolted to lateral screen stiffeners 92a, b, near their ends. By means of rubber mounting strip 80 and spring mounts 94, filter element 56 is firmly but flexibly attached to filter housing side walls 55, and is free to move through its required range during operation as described below, while excess displacement is prevented.
In the preferred embodiment, each filter element assembly 56 is then fitted with an air driven impulse vibrator assembly 94 on its upper surface as shown in FIGS. 4 and 5, although the filter element assemblies may be used without the impulse vibrators. A 6" wide×2" high 304 stainless steel mounting channel 96 3-6 foot long is centered along upper lateral stiffener 92a. Channel 96 has 9/16" holes drilled through its bottom to fit over rivets protruding from lateral stiffener 92a. Backing plate 99 is placed below lower stiffener 92b and aligned with mounting channel 96. Impulse vibrator 98 is then bolted to mounting channel 96 and backing plate 99 through corresponding bolt holes 100. Bolt holes 100 are preferably spaced to place the mounting bolts 102 astride the center and lateral stiffeners, rather than through them (FIG. 4).
Referring to FIGS. 5 and 13, compressed air is supplied to the impulse vibrator assemblies 94 in pairs through a compressed air system shown generally at 104. Compressed air at 150 psi is supplied to compressed air system 104 through 3/4" ball valve 106. Compressed air then passes through a combination filter/regulator/lubricator, 107 such as Ross Model 5M11B3311, and into vibrator air supply line 108 which is mounted to the exterior of filter side wall 55. Air supply line 108 supplies compressed 90 psi air to four manifolds 110a-d, each of which supplies compressed air to four impulse vibrators, except manifold 110a which supplies three impulse vibrators. Compressed air is admitted to each of manifolds 110a-d through a 3/4" ball valve 112, and a Ross Model 2073B5001 3-way 110 VAC solenoid valve 109, which is operated intermittently to admit air to its respective manifold. Each manifold 110a-d splits into two branches 111 which pass through side wall 55, and each of which in turn splits into two branches (except single branch 113), each of which is in turn connected to one impulse vibrator 69 by a flexible air hose, preferably Gates Model 198 3/8" 180 psi air hose. Sidewall 55 is fitted with covered access openings 122 to allow access to the impulse vibrators and their associated supply piping within filter assembly 18 for maintenance and repair.
In operation, as shown in FIGS. 1-3, filter system 10 receives an approximately 45,000 scfm process air stream carrying entrained resinated solids through inlet 14. In one embodiment, the process air stream 21 is an overflow stream from a cyclone 114 containing entrained undersized resinated wood particles and fibers 118 separated from a process stream discharged from a resinated particle steam dryer unit (not shown) used in manufacturing fiberboard. Cyclone overflow air stream 21 enters filter system 10 through downcomer 116, inlet 14 and inlet guides 17 and 19. Air stream 21 enters plenum 13 which serves to reduces the velocity of the air stream, equalizes the pressure below filter assembly 32, and evenly distribute the flow of air stream 21 among the 15 filter element assemblies 56. The air velocity in the plenum 13 is preferably less than 300 feet per minute, which is the settling velocity of 500 micron or less normalized diameter resinated wood particles, to cause a portion of the particulate matter to settle out of the air stream. Air stream 21 then flows upwardly through filter element assemblies 56. A first level of separation of entrained solids occurs as air stream 21 reverses direction in the plenum 13. A portion of the entrained solids continue flowing downwardly rather than reversing direction with air stream 13, and collect in hopper 15. The remainder of the solids are carried upwardly toward filter assemblies 56 with air stream 13 as it reverses direction.
As described above, filter assemblies 56 are flat sections of 6 mesh screen supported at an angle in a flexible frame and attached to the filter housing side walls 55. Turning to FIGS. 14-17, when air stream 21 first passes through filter elements assemblies 56 (FIG. 14), most of the entrained particles and fibers pass through with the air stream, owing to the relatively large openings presented by the 6 mesh screen. The resinated particles and fibers are somewhat sticky from the adhesive resin added in the fiberboard process, and those which impact the screen wires tend to stick and begin to accumulate, initiating the formation of a filtering layer 113 (FIG. 15). As more particles and fibers accumulate, the filter element openings are eventually covered. An increasing percentage of the entrained particles and fibers is retained on the filtering layer 113 as it grows in thickness. By the time the filtering layer 113 reaches a thickness of about 1/2", it is removing an extremely high percentage of the entrained particles and fibers 118. The pressure below filter assembly 32 and the force of air stream 21 against the underside of filter element assembly 56 bows the filter element downstream (which is upwardly at an angle) about 1 1/2" at the center of the filter element assembly, and assists in holding filtering layer 113 in place against gravity (FIG. 15).
As the filtering layer 113 continues to grow, its porosity decreases, and the flow of air stream 21 is increasingly restricted, increasing the pressure below filter assembly 32. The filtering layer eventually reaches a thickness, believed to be approximately 2 to 2 1/2", where the flow of air stream 21 is restricted to a predetermined flow rate (FIG. 16). At this point, solenoid valve 109 is activated, directing a flow of compressed air to impulse vibrator 98. The action of impulse vibrator 98 momentarily deflects filter element assembly 56 upstream (downwardly), causing it to bow about 1 1/2" in the upstream direction at its center (FIG. 17). This action causes an outer portion of filtering layer 113 to break away and fall into hopper 15, while about a portion 120 (believed to be approximately 1/2" thick) of filtering layer 113 remains on filter element 56. After impulse the vibrator is deactivated, filter element 56 returns to its previous position due to effect of the pressure in plenum 13 and the force of air stream 21, which is uninterrupted during this sequence. Since a portion of the filtering layer remains on filter element 56, there is no excessive breakthrough of solids through filter element 56 during or immediately after the activation of impulse vibrator 98.
As mentioned above, filter element assemblies 56 may be constructed without impulse vibrators 98. In that case, as filtering layer 113 continues to build in thickness, a portion of it will in most cases eventually shear and fall into hopper 15. We have found, however, that filtering layer 113 will not in all cases shear before an undesirably low filtering layer porosity is reached. Therefore, it is preferable to construct filter element assemblies 56 with impulse vibrators 98 to assure a means of maintaining a minimum desirable level of porosity, and therefore throughput capacity of the filter system 10.
The air velocity through filter elements 56 is preferably greater than 10 feet per minute, more preferably greater than 13 feet per minute, and most preferably greater than about 30 feet per minute. This represents an order of magnitude increase over air velocities achievable using a bag house system in which the air speed is normally limited to the range of 1-3 feet per minute. This advantage of the present invention allows a filter system according to the present invention to be significantly more compact, and therefore more economical to construct and operate.
After passing through filter section 18, air stream 13 is substantially free of the incoming solids, and passes into vent section 16. It is then discharged from filter system 10 through air stream outlet 30.
By way of example to show the effectiveness of the present invention, an unfiltered 45,000 scfm air stream leaving cyclone 114 was discharged directly into the surrounding atmosphere and found to discharge approximately 16.5 pounds per hour of entrained resinated particles to the surrounding atmosphere. In a second example, the air stream 21 was directed downwardly air through downcomer 116 but was not filtered; no reduction in the amount of discharged solids was realized. In the third example, the air stream 21 was directed downwardly air through downcomer 116 into a filter housing having no filter element assemblies installed; approximately 12.5 pounds per hour of entrained resinated particles were discharged to the surrounding atmosphere. This reduction is believed to represent the reduction in entrained solids resulting from the reversal of air flow in plenum 13. In the final example, the air stream was directed downwardly air through downcomer 116 into a filter system according to the present invention. Approximately 0.86 pounds per hour of entrained resinated particles were discharged to the surrounding atmosphere, representing a significant improvement in filtration realized by use of prior art filters. It is preferable that a filter system according to the present invention remove more than about 80% of the entrained solids, more preferably more than about 90%, and most preferably more than about 95%. It must be appreciated that the present invention requires considerably less expense and effort to install, operate, and maintain than a bag house installation, or other prior art filtering systems.
Referring to FIGS. 1,2, and 3, solids falling into hopper 15 collect in auger assembly housing 37 and are continuously conveyed by auger 40 (FIG.3) to solids discharge 44. The solids pass through solids discharge 44 and through discharge valve 50 and discharge chute 46 into bin 48. Bin 48 is periodically emptied as required.
When operated as described, the preferred embodiment is suitable for continuous operation. As will be recognized by those skilled in the art, size limitations on commercially available filter screen materials may impose an upper limit on the capacity of a filter system according to the present invention. It may be therefore preferable to operate two identical units side-by-side in tandem. The inlets of the side-by-side units may or may not be interconnectable. In this way, the required total capacity can be achieved, and an operational problem in one unit will not cause the entire filtering process to be halted.
Having describe the preferred embodiment of the present invention, those skilled in the art will recognize numerous changes in detail, dimensions and materials which may be made without departing from the scope of the following claims. | An apparatus and process are provided for removing particles from an air stream by filtration, particularly wood particles which have been treated with a resinous material, and which therefore are somewhat sticky. The apparatus is a filter system in which an air stream carrying the resinated particulates is directed upwardly through a set of filter elements which are arranged in a generally sawtooth pattern. The filter elements include a relatively large mesh screen to which the sticky particulates adhere and form of a filtering layer on the mesh in situ. As the filtering layer grows, its porosity is continually reduced, until it reaches a minimum acceptable level, at which time the filter elements are vibrated to cause a portion of the filtering layer to fall away, leaving a portion of the layer adhering to the filter element. In this way, continuous, high-efficiency filtering of a sticky particulate from an air stream is achieved. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application Ser. No. 60/773,419, filed Feb. 15, 2006.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The present invention relates to projection systems where multiple projectors are utilized to create respective complementary portions of a projected image, which may be a video or still image. More particularly, the present invention relates to methods of calibrating and operating such systems. According to one embodiment of the present invention, a method of calibrating a multi-projector image display system is provided. According to the method, non-parametric calibration data for the display system is recovered and used to generate a non-parametric mapping of positions in each projector to their position within a common global reference frame of the display system. Local parametric models that relate to the display surface are generated using a canonical description that either represents the image projection screen or the expected position of neighboring points when projected onto the screen. In addition, these local parametric models may represent the expected position of points in one device, e.g., a projector, when they are known in a second device, e.g., a camera. These local parametric models are compared with data points defined by the non-parametric calibration data to identify one or more local errors in the non-parametric calibration data. The local errors in the non-parametric calibration data are converted to data points by referring, at least in part, to the local parametric models. Although the conversion may be solely a function of the parametric model, it is contemplated that the conversion may be a function of both the parametric model and the non-parametric mapping, e.g., by referring to the predicted data points given by the parametric models and measurements taken from the non-parametric mapping. The projectors are operated to project an image on the image projection screen by utilizing a hybrid calibration model comprising data points taken from the non-parametric model and data points taken from one or more local parametric models.
[0003] In accordance with another embodiment of the present invention, a method of operating a multi-projector display system is provided. According to the method, the display system is operated according to an image rendering algorithm that incorporates a hybrid parametric/non-parametric calibration model.
[0004] In accordance with another embodiment of the present invention, a method of calibrating an image display system is provided. The system comprises a plurality of projectors oriented in the direction of an image projection screen and at least one calibration camera. According to the method, the calibration camera captures k distinct images of the image projection screen. All projectors contributing to each captured image render a set of fiducials captured by the calibration camera. A set of three-dimensional points corresponding to camera image points are computed as respective intersections of back-projected rays defined by the points and a canonical surface approximating the projection screen. The points are matched with projected fiducials to generate a set of corresponding match points. The set of three-dimensional points observed in different camera views are represented as a set of 3D surface points with a known neighborhood function. The 3D points are modeled as a constraint system such that the error distance between two points seen in two different camera views are computed as the geodesic distance between the first point, as seen in the second view, and the second point, as seen in that same view. Points that correspond to the same projector location but have different locations on the 3D surface are adjusted according to an error metric that minimizes the total error represented in the constraint system.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0005] The following detailed description of specific embodiments of the present invention can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
[0006] FIGS. 1 and 2 are schematic illustrations of an image projection system that may be calibrated according to the methodology of the present invention; and
[0007] FIG. 3 is a flow chart illustrating a calibration method according to one embodiment of the present invention.
DETAILED DESCRIPTION
[0008] Generally, various embodiments of the present invention relate to calibration techniques that utilize local parametric models in conjunction with global non-parametric models. Although the calibration methodology of the present invention has broad applicability to any image projection system where an image or series of images are projected onto a viewing screen, the methodology of the various embodiment of the present invention are described herein in the context of a complex-surface multi-projector display system referred to as the Digital Object Media Environment (DOME).
[0009] Referring to FIGS. 1 and 2 , the DOME 10 is composed of a vacuum-shaped back projection screen 20 that is illuminated by a cluster of projectors 30 (P 1 -P 4 ) mounted below the projection surface in a mobile cabinet 40 . Each projector 30 is connected to a projection controller 50 , which may comprise a single computer or a series of personal computers linked via an Ethernet cable or other suitable communications link. The controller 50 provides each projector with rendered images that contribute to the image display. A pan-tilt camera 60 is mounted within the DOME cabinet and is used in the calibration processes described herein. User head-positions are tracked via one or more wireless optical head-tracking units 70 or other suitable head-tracking hardware mounted to the DOME device 10 . Head tracking enables the user 80 to move their head or body through the computer generated scene while the image 90 is continually updated to reflect the user's current eye positions. Given the dynamic head position of each user, the projectors can be controlled to generate images 90 that will synchronously provide users with the perception that the object being visualized is situated within the spherical DOME surface 20 .
[0010] Referring to FIG. 1 , at each instant a ray P v that passes from the center of projection of the user 80 to a point on the image 90 intersects the spherical surface 20 and defines what color should be projected at that point on the spherical DOME surface 20 . System calibration determines what projector and ray P p is required to illuminate the point. Once calibrated, the projectors 30 and the controller 50 cooperate to render distinct images for both users 80 . The DOME system 10 can be self-contained in a rolling cabinet that can be moved from one room to the next. Although the illustrated embodiment utilizes four projectors to illuminate a display surface that is approximately 32 inches in diameter, the calibration and rendering principles introduced herein are equally applicable to displays of different resolutions and sizes and display surfaces of arbitrary shape.
[0011] Referring now to the flow chart of FIG. 3 , data regarding the geometry of the projection screen 20 and the respective geometric positions of the projectors 30 are input to initialize the illustrated calibration routine (see steps 100 , 102 ). Non-parametric calibration data is then recovered utilizing the input data (see step 104 ) and is used to generate a non-parametric model of the display system (see step 106 ) that maps points in each projector to points in a global display space. Non-parametric calibration data may be recovered in a variety of ways. For example, and not by way of limitation, when projecting onto an irregular surface, or when the projector optics induce radial distortion in the projected image, the resulting image warp can be described as a point-wise map, e.g., a lookup table, encoding the projected positions of projected pixels on a pixel-wise basis or as a surface mesh whose vertices are points in the global display space that correspond to observations and whose edges represent adjacency. For the purposes of defining and describing the present invention, it is noted that data recovery should be read broadly enough to cover construction, calculation, generation, retrieval, or other means of obtaining or creating this non-parametric mapping of projector pixels to a common coordinate system.
[0012] Once the non-parametric model has been established (see step 106 ), canonical surface data is used to apply local parametric models to the global, non-parametric calibration data (see steps 108 , 110 ). In this manner, the inherent uniformity of the local parametric models can be used to correct local artifacts and other discontinuities generated by the global, non-parametric calibration data. Broader application of the local parametric models is discouraged here because, although the parametric calibration data helps guarantee smooth calibration across the projector field by minimizing local irregularities within a single projector, global parametric solutions are typically ineffective between adjacent projectors and can lead to abrupt geometric discontinuities at projector edges. In addition, strict adherence to a parametric model often requires that the model be correct and in correspondence with the display surface over a large area, while multiple, local models typically only need to describe how points relate to one another locally.
[0013] The calibration scheme illustrated in FIG. 3 is a fundamentally non-parametric system that incorporates parametric constraints in local regions to detect and correct non-smooth areas in the calibration map. As is noted above, the calibration routine generally proceeds in two stages. First, the non-parametric calibration data is recovered (see step 106 ). This data is globally accurate, but subject to some local perturbances due to image processing, display non-uniformity, or other artifacts. The non-parametric phase of model acquisition determines a mapping from each projector pixel to its corresponding position in a common coordinate system. Typically, the parametric models are only applied once projector pixels have been mapped to a common, global space.
[0014] Once this global, non-parametric model has been acquired (see step 108 ), the local parametric models are applied over local regions (see step 110 ). If the observed, non-parametric model differs significantly from the predicted, parametric model, individual points are identified as local errors (see step 112 ). These local errors are eliminated from the non-parametric model by replacing the perturbed local data points within the non-parametric model with a corresponding point generated by the parametric model (see step 114 ). This replacement step can include, but is not limited to, a straightforward evaluation of the parametric model at an interpolated point or some weighted contribution of the observed point and the point implied by the parametric model. By using the parametric model independently, in small regions, the global problems typically associated with parametric calibration data is avoided, while retaining the local consistency that the parametric model provides. Calibration results can be verified by generating a calibration image that is configured such that errors in the hybrid calibration routine can be readily identified by a user 80 or one or more image analysis cameras when the image is displayed on the projection screen. For example, and not by way of limitation, the calibration image may be constructed as a 3D mesh and displayed on the projection screen 20 . An example of the use of a suitable mesh is described in detail below with reference to the multi-projector system 10 illustrated in FIGS. 1 and 2 .
[0015] Thus, in the multi-projector calibration scheme illustrated in FIG. 3 , each projector pixel is registered to a canonical surface that can approximate the actual display surface. Local perturbations of these mappings account for deviations from the canonical surface. These perturbations, which can arise from screen surface abnormalities, error in the estimated camera position, and differences in the canonical model and true display shape, are classified as local errors and are corrected by replacing perturbed local data points within the non-parametric model with a corresponding point generated by the parametric model. Likewise, a new point can be generated through a weighted combination of the point predicted by the local parametric model and the existing data point. This approach is motivated the observation that local errors, i.e., discontinuities in the projected image where none exists on the projection surface, are far more problematic than global, correlated errors.
[0016] For example, and not by way of limitation, in the multi-projector system 10 illustrated in FIGS. 1 and 2 , a hemisphere is the canonical model, but the true shape of the display surface is a hemisphere intersected with a cone. The pan-tilt camera 60 actuates to several overlapping view positions to capture k distinct images such that all points on the display surface 20 are seen in at least one image. For each camera position, all visible projectors 30 (P 1 -P 4 ) render a set of Gaussian fiducials that are then captured in the camera 60 . Using binary encoding techniques, the observed fiducials are matched with projected targets to generate a set of corresponding match points. For a given pan-tilt position k, the translation [xyz] I T and rotation parameters of the camera 60 are computed from an estimated initial position of the camera in the world reference frame. The camera intrinsics, M are recovered before the camera 60 is placed in the DOME 10 and are then coupled with each view position to derive a complete projection matrix:
P k = M [ e 1 · r 1 k e 1 · r 2 k e 1 · r 3 k - R 1 T T x e 2 · r 1 k e 2 · r 2 k e 2 · r 3 k - R 2 T T y e 3 · r 1 k e 3 · r 2 k e 3 · r 3 k - R 3 T T z 0 0 0 1 ] C w p
where e i are the basis vectors of the estimated coordinate system for the camera 60 in the pan-tilt reference frame, r i k are the basis vectors for pan-tilt frame at position k, and T is the estimated offset from camera to pan-tilt. R i is the i th column of the upper left 3×3 rotation components of the transform matrix. Finally, C w p is the coordinate system change from world, i.e., from where the canonical surface is defined to the estimated frame of the pan-tilt camera 60 .
[0017] Given the assumption that observed points in the camera plane arise from projected fiducials on the canonical surface, then the three-dimensional point [x y z] T corresponding to image point (i, j) k is computed as the intersection of the canonical surface with the back-projected ray defined by the point and focal length f, P k −1 [0001] T +λP k −1 [0011] T Preferably, the observed match points are back-projected prior to evaluation and application of the parametric model.
[0018] Because the canonical surface in the case of the DOME 10 is a hemisphere, the center of a match point in the projector frame p p can be related to a corresponding point in the camera p c via a second degree polynomial, e.g., p c =P(p p ). This locally parametric model can be used to eliminate invalid match points and dramatically increase the robustness of the calibration phase. The locally parametric model is only used to eliminate potentially noisy match points and does not typically play a role in global calibration.
[0019] The nine parameters of P can be recovered via a robust least squares fit, for a given match point over a 5×5 grid of neighboring points. Typically, the match point under consideration is not used during the fit. Instead, the distance between the match point and the fit model P is measured and if this distance exceeds some threshold, the match point is considered to be in error, and is discarded. The local parametric model is then used to interpolate a new match point at this location.
[0020] This set of three-dimensional points observed in different camera views must be registered to a single three-dimensional point cloud. If the same projector point is seen in multiple views only one is selected by iterating through multiple camera views and adding only unique points until the point cloud is fully populated. Next, a 3D Delaunay triangulation is performed on this point cloud to compute neighbor relations.
[0021] Finally, this 3D mesh is modeled as a constraint system in which each edge is assigned a weight of one and a length, i.e., an error distance, that corresponds to the separation of the two points on the sphere. In the case when two points arise from the same camera view, the distance is equivalent to the geodesic distance. However, if the two points p k 1 and p 1 2 are seen in two different camera views, the distance between the two points D(p k 1 ,p 1 2 ) is computed as D(p 1 1 ,p 1 2 ), i.e., the geodesic distance between the first point p 1 1 as seen in the second view, and the second point p 1 2 as seen in that same view.
[0022] Following error distance assignments, the constraint model is relaxed in order to minimize the total error contained in the constraint system. This minimization phase may use a variety of minimization techniques including traditional gradient, downhill simplex, simulated annealing, or any other conventional or yet to be developed energy minimization technique. As a result, local errors are distributed over the mesh, including those arising from error propagation between views, error in estimated camera positions, improperly modeled radial distortion, etc. This yields a perceptually consistent calibration across all projectors 30 .
[0023] Once the projectors 30 have been calibrated, a cooperative rendering algorithm then generates a frame-synchronized image for each user's head position. Although the projectors could be dynamically assigned to each viewer 80 based on their relative head positions, it is often sufficient to partition the set of pixels into two distinct views that illuminate opposite sides of the spherical DOME surface 20 . In this manner, each user 80 can see a correct view of the model being visualized for collaborative purposes. Image rendering may be controlled in a variety of conventional or yet-to-be developed ways, including those where two-pass algorithm is utilized to estimate the projection surface automatically.
[0024] At each frame, the head-positions of the viewers 80 are determined via the head-tracking units 70 and then distributed to individual projection clients or to an integrated controller 50 emulating the clients via a multi-cast signal over a local network or other communications link. Each rendering client then generates an image of the object from the viewpoint of the current head-position.
[0025] The rendered view for each projector 30 is then registered with the global coordinate system by back-projecting the rendered frame buffer onto the display surface 20 . This can, for example, be accomplished via projective texture mapping or any other suitable projection routine. Finally, it is contemplated that intensity blending can be incorporated into the projection routine by using traditional multi-projector blending or modified multi-projector blending routines including, for example, those that utilize a distance metric computed on the sphere.
[0026] It is noted that recitations herein of a component of the present invention being “configured” to embody a particular property, function in a particular manner, etc., are structural recitations, as opposed to recitations of intended use. More specifically, the references herein to the manner in which a component is “configured” denotes an existing physical condition of the component and, as such, is to be taken as a definite recitation of the structural characteristics of the component.
[0027] It is noted that terms like “preferably,” “commonly,” and “typically” are not utilized herein to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the present invention.
[0028] Having described the invention in detail and by reference to specific embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims. More specifically, although some aspects of the present invention are identified herein as preferred or particularly advantageous, it is contemplated that the present invention is not necessarily limited to these preferred aspects of the invention. For example, although the calibration methodology of the present invention has been described herein in the context of a complex-surface multi-projector display system referred to as the Digital Object Media Environment (DOME), the appended claims should not be limited to use with the DOME or similar projection systems unless they expressly recite the DOME. | The present invention relates to projection systems where multiple projectors are utilized to create respective complementary portions of a projected image. More particularly, according to one embodiment of the present invention, a method of calibrating a multi-projector image display system is provided. According to the method, non-parametric calibration data for the display system is recovered and used to generate a non-parametric model of the display system. Local parametric models relating to the display surface of the projection screen are generated using canonical surface data representing the image projection screen. The local parametric models are compared with data points defined by the non-parametric calibration data to identify one or more local errors in the non-parametric calibration data. The local errors in the non-parametric calibration data are converted to data points defined at least in part by the local parametric models and the projectors are operated to project an image on the image projection screen by utilizing a hybrid calibration model comprising data points taken from the non-parametric model and data points taken from one or more local parametric models. Additional embodiments are disclosed and claimed. | 6 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] The present invention relates to an improved side bearing design for mounting on a railroad car truck bolster that allows long travel, substantial weight reduction, improved hunting and curving characteristics, and various safety features.
[0003] 2. Description of Related Art
[0004] In a typical railway freight train, such as that shown in FIG. 1, railway cars 12 , 14 are connected end to end by couplers 16 , 18 . Couplers 16 , 18 are each received in draft sills 20 , 22 of each respective car along with hydraulic cushioning or other shock-absorbing assemblies (unshown). Draft sills 20 , 22 are provided at the ends of the railway car's center sill, and include center plates that rest in center plate bowls of railway car trucks 26 , 28 .
[0005] As better shown in FIG. 2, each typical car truck 26 includes a pair of side frames 30 , 32 supported on wheel sets 34 , 36 . A hollow bolster 38 extends between and is supported on springs 40 mounted on the side frames. A bolster center plate 24 is provided having a central opening 42 . The bolster center plate bowl 24 receives and supports a circular center plate of the draft sill 20 . Side bearing pads 60 are provided laterally to each side of center plate 24 on bolster 38 . Side frames 30 , 32 comprise a top member 44 , compression member 46 , tension member 48 , column 50 , gib 52 , pedestal 54 , pedestal roof 56 , bearing 58 and bearing adapter 62 .
[0006] Constant contact side bearings are commonly used on railroad car trucks. They are typically located on the truck bolster, such as on side bearing pads 60 , but may be located elsewhere. Some prior designs have used a single helical spring mounted between a base and a cap. Others use multiple helical springs or elastomer elements. Exemplary known side bearing arrangements include U.S. Pat. No. 3,748,001 to Neumann et al. and U.S. Pat. No. 4,130,066 to Mulcahy, the substance of which are incorporated herein by reference in their entirety.
[0007] Typical side bearing arrangements are designed to control hunting of the railroad car. That is, as the semi-conical wheels of the railcar truck ride along a railroad track, a yaw axis motion is induced in the railroad car truck. As the truck yaws, part of the side bearing is made to slide across the underside the wear plate bolted to the railroad car body bolster. The resulting friction produces an opposing torque that acts to prevent this yaw motion. Another purpose of railroad car truck side bearings is to control or limit the roll motion of the car body. Most prior side bearing designs limited travel of the bearings to about {fraction (5/16)}″. The maximum travel of such side bearings is specified by the Association of American Railroads (AAR) standards. Previous standards, such as M-948-77, limited travel to {fraction (5/16)}″ for many applications.
[0008] New standards have evolved requiring side bearings that have improved hunting, curving and other properties to further increase the safety and design of railcars. The most recent AAR standard is M-976 that now allows for long travel side bearings and has several new requirements, such as new specifications for bearing preloads. Preload is defined as the force applied by the spring element when the Constant Contact Side Bearing is set at the prescribed height.
SUMMARY OF THE INVENTION
[0009] There is a need for improved side bearings for railroad cars that can meet or exceed these new AAR standards, such as M-976 or Rule 88 of the AAR Office Manual.
[0010] There also is a need for side bearings with better wear characteristics to increase service life.
[0011] There further is a need for side bearings that can be designed for a particular application by incorporating design features that prevent interchangeability of incorrect components for that application.
[0012] There also is a need for a side bearing which maintains the preload force within 10% of the new condition for a long time. Preferably, this condition should be a minimum of 10 years or one million miles.
[0013] There also is a need for redesigned spring rates to improve handling characteristics of the truck and railway car.
[0014] There also is a need for a standardized set of springs that can reduce parts inventories of various custom spring sizes.
[0015] The above and other advantages are achieved by various embodiments of the invention.
[0016] In exemplary embodiments, long travel can be achieved in a side bearing arrangement for railroad car trucks by a combination of features, including reduction of base and/or cap heights and/or reduction of the spring solid height to accommodate ⅝″ travel or more before the spring is fully compressed (solid) and before the base and cap bottom out.
[0017] In exemplary embodiments, substantial weight reduction is achieved by reducing sides and thicknesses of the base and cap in areas not needed for structural rigidity.
[0018] In exemplary embodiments, improved inspection capabilities are achieved by addition of an inspection slot to the base and increasing a corresponding side cutout in the cap to provide a viewing window of considerable size that allows inspection of the spring and other internal components of the side bearing during use. This feature also is able to achieve weight saving advantages over prior designs.
[0019] In exemplary embodiments, various design features are incorporated to the base and/or cap to prevent interchangeability with improper components. This may include features that allow mating of only matching base and cap components. Such mating may further include features that prevent improper orientation of the base relative to the cap. Such interchangeability prevention features may further include features that prevent use of improper spring(s) with the matching base and cap. Also, the springs can be wound in the opposite direction of the adjacent spring to preclude one spring interfering with the travel of this adjacent spring.
[0020] In exemplary embodiments, improved, longer fatigue life is achieved by increasing the hardness of the components from Grade C to Grade E.
[0021] In exemplary embodiments, improved operation of the side bearing, including improved control and hunting characteristics, is achieved by careful control of longitudinal clearances between the cap and base. This has been found to be important to prevent excessive movement between the cap and base, as well as reduce associated impact forces, stresses and wear.
[0022] In exemplary embodiments, improved characteristics of the side bearing and service life are achieved by strategic placement of hardened wear surfaces.
[0023] In exemplary embodiments, improved tracking, curving and load leveling characteristics are achieved without adversely affecting hunting characteristics by changing the spring constant to be within a predetermined range, preferably between 4000-6000 lb/in.
[0024] In exemplary embodiments, a standardized set of three different springs are provided that can be mixed and matched in various combinations to achieve different preload values for use in a multitude of applications, while reducing the need for special, custom-designed springs for each application.
[0025] In exemplary embodiments, a better contact surface arrangement with a car body wear plate is achieved by coping the cap corners and increasing the flatness of the cap top contact surface to improve wear characteristics, such as reduced gouging.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The invention will be described with reference to the following drawings, wherein:
[0027] [0027]FIG. 1 is a schematic elevation of the coupled ends of two typical railroad cars;
[0028] [0028]FIG. 2 is a perspective view of a typical railway car truck for use with the present invention;
[0029] [0029]FIG. 3 is an exploded perspective view of an exemplary constant contact side bearing according to the invention;
[0030] [0030]FIG. 4 is a top view of an exemplary base according to the invention;
[0031] [0031]FIG. 5 is a cross-sectional view of the base of FIG. 4 taken along lines 5 - 5 ;
[0032] [0032]FIG. 6 is a top view of an exemplary cap according to the invention;
[0033] [0033]FIG. 7 is a cross-sectional view of the cap of FIG. 6 taken along lines 7 - 7 ;
[0034] [0034]FIG. 8 is a cross-sectional view of the cap of FIG. 6 taken along lines 8 - 8 configured to receive one or a plurality of springs;
[0035] [0035]FIG. 9 is an exploded perspective view of a first exemplary constant contact side bearing with three springs and a cap with a first keying feature according to the invention;
[0036] [0036]FIG. 10 is a cross-sectional view of the first exemplary side bearing of FIG. 9;
[0037] [0037]FIG. 11 is an exploded perspective view of a second exemplary constant contact side bearing with two springs and a cap having a second keying feature and a first exemplary spring lockout feature according to the invention;
[0038] [0038]FIG. 12 is a cross-sectional view of the second exemplary side bearing showing the second keying structure according to the invention;
[0039] [0039]FIG. 13 is an exploded perspective view of a third exemplary constant contact side bearing with two springs and a cap with a third keying feature and a second exemplary spring lockout feature according to the invention;
[0040] [0040]FIG. 14 is a cross-sectional view of the third exemplary side bearing showing the third keying structure according to the invention;
[0041] [0041]FIG. 15 is a cross-sectional view of the cap of FIG. 6 taken along lines 8 - 8 showing a first exemplary spring lockout configuration used with the side bearing of FIG. 11;
[0042] [0042]FIG. 16 is a cross-sectional view of the cap of FIG. 6 taken along lines 8 - 8 showing a second exemplary spring lockout configuration used with the side bearing of FIG. 13;
[0043] [0043]FIG. 17 is a cross-sectional view of the cap of FIG. 6 taken along lines 8 - 8 showing a third exemplary spring lockout configuration, useable with a single, large spring; and
[0044] [0044]FIG. 18 is a table of exemplary spring combinations usable with the claimed invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0045] A first embodiment of a side bearing according to the invention will be described with reference to FIGS. 3-8. Side bearing assembly 100 has a major longitudinal axis coincident with the longitudinal axis of a railway car. That is, when the side bearing is mounted on railway truck bolster 38 (only partially shown in FIG. 4), the major axis of the side bearing is perpendicular to the longitudinal axis of the bolster. Side bearing assembly 100 includes as main components, a base 110 , a cap 120 , and one or more resilient urging elements 130 , such as a spring or elastomer element. In the exemplary embodiment shown, there are provided three springs, outer spring 130 A, middle spring 130 B and inner spring 130 C that serve as the urging element, each of which may have a different spring constant to provide an overall combined load rating.
[0046] Base 110 is fixed to bolster 38 by suitable means. As shown, base 110 is bolted to bolster 38 by way of mounting bolts 140 , washers 142 and mounting nuts 144 passing through mounting holes 146 provided on base flanges 112 . Alternatively, base 110 could be riveted in place. Then, preferably, base 110 is not welded to bolster 38 along at least transverse sides.
[0047] As best shown in FIGS. 4-5, base 110 has opposing side walls 116 and front and rear walls 118 . Each of the front and rear walls 118 include a large, generally V-shaped opening 114 . Opening 114 serves as a viewing window allowing visual inspection of the springs 130 A-C during use of the side bearing. Opening 114 also serves to reduce weight of the base 110 .
[0048] To increase the travel length of the side bearing, walls 116 , 118 are reduced in total height by {fraction (5/16)}″ from prior designs, such as that used in U.S. Pat. No. 3,748,001. This helps to achieve greater travel of the spring before cap 120 and base 10 mate and prevent further travel. In an exemplary embodiment, base 110 has a total height of 3.312″ (±0.030), with walls 116 , 118 extending approximately 2.812″ above flange 112 .
[0049] Referring to FIGS. 6-8, cap 120 is cup-shaped and includes downwardly extending side walls 121 , and downwardly extending front and rear walls 122 that surround base 110 in a telescoping fashion. Front and rear walls 122 are provided with a large, generally inverted V-shaped notch 124 corresponding in location with opening 114 on base 110 to assist in forming the viewing window. Side walls 121 also include a notch 126 . The downwardly extending walls 121 , 122 of cap 120 overlap base 110 in such a fashion that even when the spring(s) 130 are at their free height or in an uncompressed condition, there is still provided an amount of overlap between walls 121 , 122 and walls 116 , 118 . This eliminates the need for a retaining pin to prevent separation of the cap relative to the base.
[0050] Cap 120 is further provided with a top contact surface 128 , lower stop surface 123 , and lower recessed spring support surface 127 . Preferably, all peripheral edges 129 are coped. This serves several purposes. It reduces weight of the cap. Moreover, by coping the corners, there is a better contact surface is made that abuts against a car body wear plate (unshown but located on the underside of a car body immediately above cap 120 in use). In particular, by having coped corners, it has been found that less gouging occurs on the car body wear plate when the cap slides and rotates in frictional engagement with the car body wear plate during use. To further assist in a better contact surface, top contact surface 128 is formed substantially flat, preferably within 0.010″ concave or 0.030″ convex to further improve wear characteristics. In particular, this bias reduces the chance of the edge “binding” against the wear plate and is easier to manufacture.
[0051] To assist in providing long travel of the springs, cap 120 is shortened similar to that of base 110 . In an exemplary embodiment, cap 120 is shortened in height by {fraction (5/16)}″ over previous designs to allow further travel of spring(s) 130 before cap 120 and base 110 mate and prevent further travel. Cap 120 preferably has a total cap height of 3.50″, with side walls 121 and 122 extending downward approximately 2.88″ below lower support surface 127 . This allows the cap to overlap farther onto base 110 before sides 121 , 122 hit flange 112 .
[0052] As mentioned, the inventive side bearing cap 120 and base 110 can be used with one or more urging members, such as springs 130 . To achieve long travel of at least ⅝″, it is preferably to reduce the spring solid height from that used in prior designs. This is because prior spring designs would have gone solid before ⅝″ of travel was achieved. That is, the individual spring coils would have compressed against each other so that no further compression was possible.
[0053] Many exemplary spring configurations were designed and tested. Suitable exemplary versions are provided in table form in FIG. 18. Each of these are capable of travel during use of at least ⅝″ (0.625″). That is, each have a travel from a loaded height (such as 4.44″) to a fully compressed height (such as 3.68″) where the spring is fully compressed or the cap and base mate that equals or exceeds ⅝″ of travel.
[0054] Although three springs per side bearing are described in many embodiments, the invention in not limited to this and fewer, or even more, springs could be used. In fact, the number and size of springs may be tailored for a particular application. For example, lighter cars will use a softer spring rate and may use softer springs or fewer springs. Similarly, multi-unit articulated cars may use lighter or fewer springs because such cars use four side bearings instead of two per car. As such, the load carrying capacity of each can be reduced. Also, it has been found that better performance can be achieved through use of substantially softer spring constants than previously used. This has been found to provide a suspension system with a slower reaction time, which has been found to achieve improved tracking and curving, without adversely affecting hunting. This also has been found to result in reduced sensitivity to set-up height variations or component tolerances so as to achieve a more consistent preload on the truck system. This tends to equalize the loading and allow a railcar to stay more level , with less lean or roll both statically and dynamically.
[0055] To obtain longer fatigue life, the material used for base 110 and cap 120 has been changed from Grade C steel to Grade E steel, which is harder and stronger. To assist in longer service life, hardened wear surfaces are provided on the outside surfaces of base walls 116 .
[0056] Additionally, in an exemplary preferred embodiment, to prevent excessive movements and accelerated wear, reduced longitudinal clearances between cap 120 and base 110 are provided by reducing the tolerances from prior values. This can be achieved, for example, by more closely controlling the casting or other formation process of the cap 120 and base 110 side walls. In a preferred embodiment, base 110 has a longitudinal distance of 7.000″ (+0.005/−0.015) between outside surfaces of side walls 116 and internal surfaces of side walls 122 of cap 120 have a longitudinal distance of 7.031″ (+0.000/−0.020). This results in a closely controlled combined longitudinal spatial gap having a minimum of 0.006″ and a maximum of 0.046.″ The minimum is achieved when base side walls 116 are at the maximum tolerance of 7.005″ and the cap side walls 122 are at the minimum tolerance of 7.011.″ The maximum is achieved when the base side walls 116 are at the minimum tolerance of 6.985″ and the cap side walls 122 are at the maximum tolerance of 7.031.″
[0057] Also, it is important to keep the distance from top surface 128 to lower stop surface 123 at 1.125″ (±0.030) so as to ensure travel of at least ⅝″ before full compression of cap 120 on base 110 .
[0058] Because of the possibility of various spring combinations, it is desirable to provide a safety feature that prevents interchangeability of improper components for a given application. To achieve this, exemplary embodiments provide keying features on both the cap 120 and base 110 to prevent mismatch of components. Also, caps 120 can be provided with spring lockout features that prevent improper combinations of springs to be used.
[0059] [0059]FIGS. 9-10 show a first exemplary embodiment in which all three springs 130 A, 130 B and 130 C are used. This application would be used for heavier railcars and can use any of the three-spring combinations listed in FIG. 18. However, a preferred combination of springs is the bottom example in FIG. 18. Use of a three-spring combination is particularly suitable for railcars in excess of 50,000 lbs, typically between 50,000 lbs and 110,000 lbs. Such cars are often boxcars, steel coal cars, multi-level auto rack cars and the like.
[0060] This configuration includes a first keying feature configuration consisting of vertical half-circle recessed keying features 150 provided on opposite diagonal outside corners of base 110 and corresponding vertical half-circle protruding keying features 160 provided on corresponding inside corners of cap 120 . With these keying features, base and caps for only this application will be allowed to mate and overlap. This prevents mismatching of components. Moreover, the keying features 150 , 160 preferably prevent improper orientation of components. For example, the keying feature should preferably not prevent use of a proper cap, but rotated 180° from a correct orientation.
[0061] [0061]FIGS. 11-12 show a second exemplary embodiment in which only the two heavier springs 130 A and 130 B are used. This application would be used for medium weight railcars and can use any of the different outer and middle springs listed in FIG. 18. This combination of springs is particularly suited for railcars weighing between about 40,000 lbs. to 65,000 lbs.
[0062] This configuration includes a second keying feature configuration consisting of vertical half-circle recessed keying features 150 provided on different opposite diagonal outside corners of base 110 and corresponding vertical half-circle protruding keying features 160 provided on corresponding inside corners of cap 120 . With these keying features, base and caps for only this application will be allowed to mate and overlap. This prevents mismatching of components. For example, even if rotated, cap 120 for this embodiment will not mate with the base of the previous embodiment.
[0063] [0063]FIGS. 13-14 show a third exemplary embodiment in which only springs 130 A and 130 C are used. This application would be used for lighter railcars or multi-unit railcars and can use any of the different outer and inner spring combinations listed in FIG. 18. This combination of springs is particularly suited for use with railcars weighing less than about 45,000 lbs. It is also suited for use in center trucks of articulated cars, which use four side bearings per truck rather than the standard two. Because there are twice as many side bearings, the spring rate can be lower for each side bearing.
[0064] This configuration includes a first keying feature configuration consisting of vertical half-circle recessed keying features 150 provided on same-side opposite outside corners of base 110 and corresponding vertical half-circle protruding keying features 160 provided on corresponding inside corners of cap 120 . With these keying features, base and caps for only this application will be allowed to mate and overlap. This prevents mismatching of components. For example, cap 120 of this embodiment will not fit on either of the previous two embodiments.
[0065] The use of the above keying features 150 , 160 achieve proper matching of base and cap components. However, additional features are needed to ensure that the proper spring combinations are used for a particular application. The embodiment of FIGS. 9-10 uses all three springs. Because of this, there is no need for a spring lockout feature. As such, the underside of cap 120 in this embodiment will appear as in FIG. 8. However, in the FIGS. 11-12 embodiment, only the two outer springs 130 A and 130 B are used. To prevent usage of spring 130 C, lower recessed spring support surface 127 of cap 120 in FIG. 15 is provided with a suitable spring lockout feature 170 that prevents insertion of an improper spring. In this case, spring lockout feature 170 may be a boss that protrudes downwardly and is sized to prevent use of small spring 130 C, but is sized to not interfere with placement of springs 130 A or 130 B against spring support surface 127 on the interior of cap 120 . Similarly, in the FIGS. 13-14 embodiment, lower recessed spring support surface 127 of cap 120 in FIG. 16 is provided with a second, exemplary spring lockout feature 170 that protrudes downwardly and prevents use of middle spring 130 B, without interfering with placement of springs 130 A or 130 C. Other configurations of a spring lockout feature 170 are contemplated. For example, if only outer spring 130 A was desired to be used, a third exemplary spring lockout feature 170 could be provided as in FIG. 17 to prevent use of both the inner and middle springs 130 B and 130 C. Thus, the combination of base and cap keying features 150 , 160 and the spring lockout features 170 prevent interchanging of improper components for a particular application.
[0066] Additional advantages are achieved by use of specific spring constants in the inventive side bearing. Prior three-spring designs had dramatically higher spring constants, which were believed to be necessary to achieve proper load support and cushion to the railcar. For example, for a 65,000 lb. railcar many prior designs had a combined load rate of about 7100 lb/in (3705 lb/in for the outer spring, 2134 lb/in for the middle spring, and 1261 lb/in for the inner spring). The top example in FIG. 18 falls into this category. However, it has been found that substantially improved ride and load balancing characteristics can be achieved by dramatically reducing the load rate of the springs, in effect making them much softer. Many benefits can be achieved if the combined load rate is between about 4,000-6,000 lbs/in. If the rate is lowered much below 4,000 lb/in, it is possible that the side bearing will disengage from contact with the bottom of the car body, which is undesirable. As the load rate increases towards 6,000 lb/in, similar benefits can be achieved. However, the higher in this range, the more sensitive the springs are to manufacturing tolerance and set-up deviations.
[0067] A preferred embodiment according to the invention is shown at the bottom of FIG. 18 and uses a total combined load rate of about 4506 lb/in (2483 lb/in for the outer spring, 1525 lb/in for the middle spring, and 498 lb/in for the inner spring). A spring combination near the bottom of the preferred range of 4,000-6,000 lb/in. has been found particularly suitable for several reasons. First, it allows the side bearing to become less sensitive to set-up height variations and tolerances. That is, small deviations from one side bearing to another on a truck have been found to have little effect on the achieved preload. Thus, a spring with this range of preload has been found to be capable of a more consistent preload from side bearing to side bearing, even if there are minor set-up height or other tolerance variations or non-uniformities. This tends to equalize the loading and allow a railcar to stay more level, with less lean or roll both statically and dynamically. Second, such lowered rates provide a suspension system with a slower reaction time, which has been found to achieve improved tracking and curving, without adversely affecting hunting. However, as mentioned, increased spring rates approaching 6,000 lb/in. can be used. However, to achieve similar performance, various design tolerances must be more tightly controlled, because as the spring rate increases towards 6,000 lb/in., the sensitivity to set-up and tolerance variances increases. Thus, without appropriate control of these tolerances, such deviations may result in unlevel loading, resulting in undesirable lean of the car body from a flat state if one side bearing on the truck is not set-up the same as the other.
[0068] This combination of features has also achieved great weight reduction from prior designs. For example, the exemplary side bearing 100 has been found to have a weight of only 47.3 pounds, which is down from 55.9 pounds of prior designs.
[0069] While only specific embodiments of the invention have been described and shown, it is apparent that various alternatives and modifications can be made thereto. Those skilled in the art will also recognize that certain additions can be made in these illustrative embodiments. It is, therefore, the intention in the appended claims to cover all such alternatives, modifications and additions as may fall within the true scope of the invention. | A long travel constant contact side bearing for railway cars provides better handling characteristics, achieving improved tracking and curving through use of various combinations of features. Such a long travel side bearing is able to meet recent stringent American Association of Railroads standards, such as M-976. Lowered spring rates, preferably less than 6,000 lb/in., help with stability and reduce set-up sensitivity. Reduced cap and base dimensions and spring design help achieve travel of at least ⅝″. A visual inspection windows allows ready inspection. Increased service life and wear characteristics are obtained by addition of hardened wear surfaces, improved tolerances, changes to Grade E steel, increase of top contact surface flatness and coped top surface peripheral edges. Standardized sets of spring components can be mixed and matched, requiring fewer specialty parts. Interchangeability of improper components can be prevented by a combination of keying features and/or spring lockout features. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a nock travel indicator and more particularly pertains to a bow tuning apparatus which allows a user to map the travel of a nock upon a bow string.
2. Description of the Prior Art
The use of bow tuning devices is known in the prior art. For example, U.S. Pat. No. 5,121,736 to Hawk discloses an archery bow sighting apparatus for use in effecting vertical alignment of the bow with the bow string. Furthermore, U.S. Pat. No. 4,993,397 to Cryar discloses an apparatus for calibrating archery bows. The apparatus allows the nocking point and other features to be adjusted to optimal positions. U.S. Pat. No. 2,763,156 to Garigal discloses a bow pull indicating machine for use in indicating the force and movement of a bow string attached to a resilient bow. The use of bow presses is also known in the art. For example, U.S. Pat. No. 5,222,473 to Lint; U.S. Pat. No. 5,433,186 to Corwin; and U.S. Pat. No. 5,370,103 to Desselle each disclose bow press devices for use in securing a bow during adjustment and/or maintenance.
Finally, applicant's prior patent, U.S. Pat. No. 5,954,041 entitled “Bow Calibrating Device”, the contents of which are incorporated herein by reference, discloses a device for calibrating the draw of an archery bow.
Although the devices described in conjunction with the above-referenced patents achieve their individual objectives and requirements, none of them pertain to a bow tuning apparatus with a nock travel indicator. In this respect, the bow tuning apparatus of the present invention substantially departs from those of the prior art.
BRIEF SUMMARY OF THE INVENTION
The use of bow and arrows has increased in popularity over the years. This popularity comes both in the form of target shooting and bow hunting. The most popular forms of bows today are compound bows. These bows provide an inherent mechanical advantage which reduces the pull force required at full draw. This mechanical advantage, in turn, results in increased accuracy. Those familiar with compound bows will understand the necessity to keep such bows properly calibrated. Improperly calibrated bows result in loss of accuracy and premature wear of the pulleys and wheels. Premature degradation of the bow limbs can also occur as a result of improper calibration. The present invention overcomes the problems inherent in keeping a bow properly calibrated by providing a tuning apparatus which includes a visual nock travel indicator. To this end, the present invention essentially comprises a bow tuning apparatus with a nock travel indicator. The apparatus has, as a first component, an outer frame with measuring indicia formed along the length of the outer frame. A second component is an inner frame slidably positioned within the outer frame. A first winch assembly is secured along a length of the outer frame. Cabling is secured about the first winch and has a distal end secured to the inner frame. In this manner, rotation of the winch causes inward movement of the inner frame with respect to the outer frame. A second winch assembly is secured along a length of the outer frame. Cabling is secured about the second winch assembly. An implement securing means is coupled to the distal end of the cabling of the second winch assembly. Further, a writing implement is positioned within the implement securing means. Lastly, a rigid sheet is removably coupled to the outer frame assembly.
Furthermore, it is an object of the present invention to provide an apparatus whereby a user can easily calibrate a bow.
It is a further object of the present invention to provide a device whereby the travel of the bow string can be recorded for subsequent reference.
An even further object of the present invention is to provide a calibrating device which employs winches and pulleys such that the bow can be drawn with minimal user energy.
It is still yet another object of the present invention to provide a device whereby the initial draw of the bow can be recorded, both in terms of distance and in stress.
Another object of the present invention is to provide a writing implement interconnected with the peak of the bow string such that the travel of the bow string can be recorded and non-linear bow paths may be detected.
These objects of the present invention can be achieved by providing a bow tuning apparatus with a nock travel indicator. The bow tuning apparatus has, as a first component, a mounting platform with first and second sides and a central extent. First and second deflection measuring apparatuses are located on the first and second sides of the platform respectively. An outer frame is secured to the central extent of the mounting platform. Measuring indicia is formed along the length of the outer frame. An inner frame is slidably positioned within the outer frame. The inner frame has a hollow interior. A bow press with associated rollers integral with a forward extent of the inner frame is also provided. The fourth component of the present invention is a first winch assembly secured along a length of the outer frame. A first pulley is rotatably secured at a rearward extent of the outer frame. Cabling is secured about the first winch, the first pulley, and extends within the outer frame with a distal end secured to the interior of the inner frame. In this manner, rotation of the winch causes inward movement of the inner frame with respect to the outer frame. A second winch assembly is secured along a length of the outer frame. A second pulley is secured to the rearward extent of the outer frame. Cabling is secured about the second winch assembly and the second pulley. A strain measuring device is coupled to a distal end of the cabling. An implement securing means is secured to the strain measuring device with a writing implement positioned within the securing means. Lastly provided is a sheet of plexiglass which is removably coupled to the outer frame assembly. A sheet, which has graduations marked thereon, is removably coupled to the plexiglass such that movement of the writing implement corresponds with the movement of a bow string being measured and wherein movement of the writing implement makes marks upon the sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
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:
FIG. 1 is a plan view of the bow tuning apparatus of the present invention.
FIG. 2 is a detailed side elevational view taken from FIG. 1 .
FIG. 3 is a view of the bow tuning apparatus with a bow to be calibrated positioned thereon.
FIG. 4 is a plan view of the bow tuning apparatus in the extended orientation.
FIG. 5 is a plan view of the rigid sheet employed in conjunction with the nock travel indicator.
FIG. 6 is a side elevational view of the sheet depicted in FIG. 5 .
FIG. 7 is a view of the removable sheet with graduations marked thereon.
FIG. 8 is a view of an alternative embodiment of the bow tuning apparatus of the present invention.
The same reference numerals refer to the same parts throughout the various Figures.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention relates to a nock travel indicator for use in conjunction with a bow tuning apparatus. The nock travel indicator allows a user to map the travel of a bow string thereby allowing a user to detect any misalignment or misadjustment of a bow string. In its broadest context, the present invention includes a writing implement which is secured adjacent the bow string and which records the path of the bow string on an underlying sheet. The details of the nock travel indicator, as well as additional embodiments, will be presented in greater detail hereinafter.
With reference now to FIG. 1, the preferred embodiment of the nock travel indicator 22 is depicted. This figure illustrates a mounting platform 24 which forms the major structural feature of the bow tuning apparatus 20 . Such platform 24 is defined by first and second sides as well as a central extent 26 . Furthermore, first and second deflection measuring apparatuses, 28 and 32 respectively, are movably secured to the first and second sides of the platform 24 . The nature and function of these deflection measuring apparatuses will be described in greater detail hereinafter.
With continuing reference to FIG. 1, the outer frame 34 of the bow tuning apparatus 20 is depicted. This outer frame 34 is secured to the central extent 26 of the mounting platform 24 by way of threaded fasteners, or the like, such that the platform 24 and frame 34 are fixedly secured to one another. Preferably, measuring indicia 36 is formed along the intermediate length of the outer frame 34 . The measuring indicia 36 aids users in determining the travel of a bow string in a manner more fully described hereinafter.
The tuning apparatus 20 further employs an inner frame 38 which is slidably positioned within the outer frame 34 . In the preferred embodiment, both the inner and outer frames, 38 and 34 respectively, are of a rectangular cross section and have a hollow interior. Thus, the inner frame 38 is telescopically received within the outer frame 34 such that the bow tuning apparatus 20 can be used with bows of varying shapes and sizes. Furthermore, a bow press 42 is integrally formed at the forward extent of the inner frame 38 . The bow press 42 has outer ends, each of which receives a roller 44 thereon. These rollers 44 are adapted to engage the limbs of a bow 45 secured within the apparatus 20 during a bow press operation described more fully hereinafter. The inward force of the inner frame 38 upon a properly positioned bow 45 is governed by a first winch assembly 46 .
This first winch assembly 46 is secured to the intermediate length of the outer frame 34 by way of threaded fasteners or the like. The winch assembly 46 further includes a first pulley 48 which is rotatably secured at the rearward extent of the outer frame 34 , note FIG. 1 . Cabling 52 is secured about the first winch 46 and threaded about the first pulley 48 with the distal end of the cabling 52 threaded within the interior of the outer frame 34 . The distal end of the cabling 52 is secured to the inner frame assembly. Thus, the cabling 52 is threaded within the hollow interior of both the outer and inner frames, 34 and 38 respectively, and secured to the interior of the inner frame 38 . FIG. 4 shows a partial sectional view of the cabling 52 threaded within the interior of the inner frame 38 . As such, forward rotation of the first winch assembly 46 causes the cabling 52 to be taken up about the periphery of the winch. Furthermore, the first pulley 48 provides a user with a mechanical advantage. Continued winch rotation causes the inner frame 38 to be drawn into the outer frame 34 . As noted in FIG. 3 this, in turn, causes the bow press 42 with its associated rollers 44 to engage the limbs 50 of an archery bow 45 positioned within the apparatus 20 . As is also evident from FIG. 3, with a bow 45 properly positioned within the apparatus 20 , the outer extents of the bow limbs 50 will cause outward pressure to be applied upon the deflection measuring apparatuses 28 and 32 . Each of the apparatuses is adapted to travel along the outer length of the mounting platform 24 and to measure the force exerted upon its upstanding edge 51 .
The apparatus 20 further includes a second winch assembly 54 . This second winch assembly 54 is secured along the intermediate length of the outer frame 34 in a manner similar to the first assembly. The second winch assembly 54 further includes a second pulley 56 which is secured to the rearward extent of the outer frame 34 . As with the first assembly 46 , cabling 58 is secured about the second winch assembly 54 and the second pulley 56 . However, the cabling 58 is not threaded within the interior of the outer frame 34 . Rather, the distal end of the cabling 58 is coupled to a strain measuring device 62 by way of a hook 63 . The coupling of the distal end of the cabling 58 and the strain measuring device 62 is most clearly depicted in the side elevational view of FIG. 2 . The opposite end of the strain measuring device 62 includes a second hook 65 . This second hook 65 is adapted to be removably coupled to the bow string of a bow 45 positioned within the apparatus. With continuing reference to FIG. 2, the implement securing means 64 of the nock travel indicator 22 is depicted. This implement securing means 64 is fixedly secured to the second hook 65 . The implement securing means 64 employs a threaded fastener, the rotation of which causes force to be supplied upon a writing implement 66 positioned within the securing means 64 . Other securing mechanisms are also possible. For example, a simple rubber band or a spring arrangement may also be employed. FIG. 2 also depicts a pencil or other writing implement 66 positioned within the securing means 64 . In this manner, the writing implement 66 is interconnected to the distal end of the bow string.
FIG. 1 depicts the rigid sheet 68 which is removably coupled to the outer frame 34 of the assembly. In the preferred embodiment, this rigid sheet 68 is formed entirely from plexiglass. FIGS. 5 and 6 are detailed views of the plexiglass sheet utilized upon the apparatus 20 of the present invention. As indicated, the outer ends of the sheet include pairs of threaded fasteners 73 . In this manner, the sheet 68 can be secured over the top of the outer frame assembly 34 with the fasteners 73 functioning to positively secure the sheet to the apparatus 20 . FIG. 7 illustrates a sheet 72 with graduations 74 marked thereon. Such sheet 72 is adapted to be removably coupled to the upper surface of the plexiglass sheet 68 through the use of a removable adhesive or the like. The sheet 72 together with the plexiglass 68 are adapted to be positioned underneath the writing implement 66 positioned within the securing means 64 . Thus, as can be appreciated from FIG. 2, movement of the writing implement 66 causes marks to be made upon the sheet 72 depicted in FIG. 7 .
The apparatus thus described can be used in any one of five modes of operation: nock travel indication; synchronization and recording; weakened limb detection; draw length documentation; and finally, for use as a bow press. Each of these usages will be described in greater detail hereinafter.
When being used as a nock travel indicator, care should be taken that the second hook 65 of the securing means 64 is secured to the center of the bow string. Thereafter, the second winch assembly 54 is employed to draw the bow. As this is done, care should be taken to monitor the weight scale 62 . As the bow is drawn, the scale will build until it reaches the maximum draw weight and then the holding weight will suddenly let off. This point is known as the valley and is the draw point which requires the least amount of draw weight. This draw weight is also known as the holding weight. Furthermore, the distance the string is pulled to achieve the holding weight is known as the draw length. At this point, the draw length should be recorded by way of measuring indicia 36 . Furthermore, the weight should likewise be recorded at the bottom of the valley. Subsequent drawing of the bow via the winch 54 will cause weight to build up again. This is known as the wall. The draw length and weight should again be recorded at this point. Thereafter, the user should install the chart 72 on the plexiglass panel 68 . Preferably the chart is installed upon the plexiglass with arrows to indicate the top and bottom of the bow. FIG. 7 illustrates the form of the chart preferably used with notations of top cam and bottom cam indicating the top and bottom of the bow respectively.
As is apparent from FIG. 2, the location of the writing implement is offset with respect to the location of the bow string, which is located in hook 65 . Consequently, vertical adjustment should be undertaken to accommodate for this. Typically, there will be about a ¾ inch difference between the location of the writing implement and the location of the string. When the writing implement is inserted into the securing means 64 it should be pushed in until a slight pressure is applied to the chart. Thereafter, the writing implement holder should be secured. Next, the bow should be released slowly by way of the second winch 54 . This will cause the writing instrument to scribe a line on the chart. As the bow string moves up, the line drawn will represent the travel of the nock and of the arrow in an up and down motion upon normal release in a vertical position. A straight line will indicate a bow which is in proper tune. An acceptable line can have a {fraction (1/16)} deviation from straight. Lines in the shape of an “S” indicate that the bow is in need of adjustment. At this point the chart can be saved for taking future tune readings.
The manner in which the apparatus can be employed for synchronization will next be described. The initial steps for synchronization are the same as described above in conjunction with nock travel indication. However, the scribed line should be examined to decipher the lead cam from the trailing cam. Specifically, the scribed line will arch toward the lead cam and away from the trailing cam. Once this determination is made, adjustments should be conducted such that the trailing cam “catches up with” the lead cam. This is accomplished by twisting the end of the buss cable on the trailing cam to thereby shorten its length. Alternatively, the yoke end of the same cable can have one of its sides removed and rotated around the other side of the yoke one time placing it on the same axle and from which it came. Again, this tightens and shortens the length of the cable. In this manner, the cables are twisted and untwisted to make adjustments on the synchronization of the cams. When twisting the cable to achieve timing, the number of twist changes should be recorded in both number and direction.
The apparatus is employed in draw length documentation by recording the draw length upon the Chart of FIG. 7 . In this manner subsequent draw lengths can be compared and optimal draw lengths can be repeated.
Employing the apparatus for weakened limb detection will next be described. Such is accomplished by first repeating the steps indicated above with respect to the nock travel indication. Thereafter, with the bow at full draw the swing arm devices, or deflection measuring apparatuses 28 and 32 , are brought to the three inch positions. This position is measured from the center of the top axle and likewise the bottom axle to the swing arms hanging straight down against the roll pin. Thereafter, the bow is released about one inch. As this is done, care should be taken to make sure to lock the winch to prevent injury. Next, the distance between the axles and the vertically hanging swing arms are measured. If the limbs are in good condition, these measurements should be very close. However, measurements which are different indicate that the bow has a weak or damaged limb. Even with a weakened limb, the bow can be tuned to shoot properly by achieving straight nock travel. The use of the apparatus as a bow press will now be described. Once a bow is determined to be in need of adjustment, the apparatus can be employed as a press for use while the bow is being adjusted. The first step for use as a bow press is to apply the pressure on the bow strings and cables. Thereafter, with the bow at full draw and making sure that the swing arm devices at the top and bottom are at their extreme outermost positions, the bow press is lowered. This is achieved by way of the first winch assembly 46 . Thereafter, the press is lowered until the rollers come into contact with the bow's limbs. Care should be taken to avoid sights and stabilizers. Next, the bow's pressure is slowly released by way of the second winch.
FIG. 8 illustrates a secondary embodiment of the bow tuning apparatus of the present invention. This apparatus employs an alignment bracket 76 slidably positioned upon the outer frame 34 . This alignment bracket 76 may be used to insure that the bow is properly positioned upon the device 20 . The apparatus depicted in FIG. 8 may be used in conjunction with the nock travel indicator 22 described in conjunction with FIGS. 1 through 7.
As to the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided.
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. | A bow tuning apparatus with a nock travel indicator includes a mounting platform for mounting a compound bow having cam wheels, the mounting platform having first and second deflection measuring gauges on respective first and second sides, to contact the cam wheels for measuring bow deflection as the bow is drawn. An outer frame is mounted to the mounting platform, the outer frame including indicia for measuring bow string travel distance. An inner frame is slidably received in the outer frame, the inner frame having a bow press with rollers to deflect the bow limbs as the inner frame is retracted into the outer frame. A first winch, having a strain gauge, is used to draw the bowstring. A marking pen may be secured to the bowstring, to mark a surface as the bowstring is drawn. A second winch is used to retract the inner frame into the outer frame, to slacken the bowstring. | 5 |
TECHNICAL FIELD
[0001] The present invention relates to an exhaust purification apparatus. Especially, the present invention relates to a urea solution injection device for a ship.
BACKGROUND ART
[0002] Conventionally, an exhaust purification apparatus is known in which a selective reducing type NOx catalyst (SCR catalyst) is arranged inside an exhaust pipe and NOx (nitrogen oxide) is reduced into nitrogen and water with ammonia as a reducing agent for decreasing the NOx in exhaust gas discharged from an internal combustion engine.
[0003] A urea solution is supplied from a urea solution injection nozzle arranged inside an exhaust pipe to exhaust gas, and ammonia is generated from the urea solution by heat of the exhaust gas so as to reduce NOx into nitrogen and water.
[0004] In the exhaust purification apparatus, when an addition amount of the urea solution against a NOx discharge amount is insufficient, NOx cannot be decreased to a target purification rate (denitration shortage). When the addition amount of the urea solution against the NOx discharge amount is excessive, NOx in the exhaust gas is decreased more than the target purification rate (over-denitration) and ammonia slip that ammonia exceeding a theoretical equivalent is discharged to the atmosphere occurs. Then, there is a configuration that a NOx sensor is provided in an exhaust pipe and control is performed so as to add the urea solution of a suitable amount against the NOx discharge amount. For example, it is like the Patent Literature 1.
[0005] However, in the NOx sensor of the exhaust purification apparatus described in the Patent Literature 1, accurate measurement of the NOx discharge amount may not be performed because of interference of ammonia. It is disadvantageous that the NOx sensor in the internal combustion engine which is operated for 24 hours such as an engine for a ship requires frequent maintenance work because of a short life of the NOx sensor.
PRIOR ART REFERENCE
Patent Literature
[0006] Patent Literature 1: the Japanese Patent Laid Open Gazette 2008-157136
DISCLOSURE OF INVENTION
Problems to be Solved by the Invention
[0007] The present invention is provided in consideration of the problems as mentioned above, and the purpose of the invention is to provide an exhaust purification apparatus which can add a urea solution of a suitable amount without measuring directly a NOx discharge amount with a NOx measurement means.
Means for Solving the Problems
[0008] The problems to be solved by the present invention have been described above, and subsequently, the means of solving the problems will be described below.
[0009] According to the present invention, an urea solution injection device of an exhaust purification device in which an urea solution is added as a reducing agent to exhaust gas of an internal combustion engine so as to reduce nitrogen oxide in the exhaust gas, includes a temperature sensor detecting a temperature of atmosphere, a humidity sensor detecting an absolute humidity or a relative humidity of the atmosphere, and a control device calculating an addition amount of the urea solution. A map, which converts an actual NOx discharge amount of the internal combustion engine driven with each rotation speed and each load under predetermined temperature and absolute humidity of the atmosphere into the standard NOx discharge amount of the internal combustion engine with each rotation speed and each load under standard conditions with a correction formula is stored in the control device. A rotation speed detection means detecting the rotation speed of the internal combustion engine and a load detection means detecting the load of the internal combustion engine are connected to the control device. The standard NOx discharge amount corresponding to the rotation speed detected by the rotation speed detection means and the load detected by the load detection means is calculated with the map, the standard NOx discharge amount is converted into the actual NOx discharge amount of the rotation speed and the load under the temperature of the atmosphere detected by the temperature sensor and the absolute humidity of the atmosphere detected by the humidity sensor with the correction formula by inverse operation, and the addition amount of the urea solution is calculated based on the actual NOx discharge amount.
[0010] According to the present invention, the addition amount is calculated in consideration of a target purification rate and a concentration of the urea solution.
Effect of the Invention
[0011] The present invention brings the following effects.
[0012] According to the present invention, the NOx discharge amount based on the characteristic of the internal combustion engine can be calculated while considering the temperature of the atmosphere and the absolute humidity of the atmosphere which influence the NOx discharge amount greatly. Accordingly, the urea solution of the suitable amount can be added without measuring directly the NOx discharge amount with a NOx sensor.
[0013] According to the present invention, the addition amount of the urea solution can be adjusted corresponding to the operating condition. Accordingly, the urea solution or ammonia of the suitable amount can be added without measuring directly the NOx discharge amount with a NOx sensor.
BRIEF DESCRIPTION OF DRAWINGS
[0014] FIG. 1 is a drawing of an exhaust purification apparatus according to an embodiment of the present invention.
[0015] FIG. 2 is a drawing partially in section of a urea solution injection nozzle of the exhaust purification apparatus according to the embodiment of the present invention.
[0016] FIG. 3 is a flow chart of control processes of an addition amount of a urea solution according to the first embodiment of the present invention.
[0017] FIG. 4 is a graph of a relation between an actual NOx discharge amount and the addition amount of the urea solution.
DETAILED DESCRIPTION OF THE INVENTION
[0018] An explanation will be given on an exhaust purification apparatus 1 according to an embodiment of the present invention referring to FIGS. 1 and 2 . In this embodiment, an “upstream side” means an upstream side in a flow direction of fluid, and a “downstream side” means a downstream side in the flow direction of the fluid. The exhaust apparatus is not limited to this embodiment and may alternatively be an air-less type apparatus which does not use pressurized air.
[0019] As shown in FIG. 1 , the exhaust purification apparatus 1 purifies exhaust gas discharged from an engine 20 . The exhaust purification apparatus 1 is provided in an exhaust pipe 21 of the engine 20 . The exhaust purification apparatus 1 has a urea solution injection nozzle 2 , a pressurized air supply pump (compressor) 6 , a pressurized air valve 8 , a urea solution supply pump 9 , a switching valve 11 , a control device 14 , a temperature sensor 12 , a humidity sensor 13 , a first supply flow path 15 , a second supply flow path 16 , a NOx catalyst 19 and the like.
[0020] The urea solution injection nozzle 2 supplies a urea solution to an inside of the exhaust pipe 21 . The urea solution injection nozzle 2 includes a tubular member, and one of sides (lower side) thereof is inserted into the inside of the exhaust pipe 21 from the outside. The urea solution injection nozzle 2 has a double pipe 3 , a liquid nozzle 4 , an air nozzle 5 and the like (see FIG. 2 ).
[0021] The pressurized air supply pump (compressor) 6 supplies pressurized air. The pressurized air supply pump 6 pressurizes (compresses) air and supplies the air. The pressurized air supply pump 6 supplies the air to an air tank 7 when a pressure of the air tank 7 becomes lower than a predetermined pressure, and stops when the pressure of the air tank 7 reaches the predetermined pressure. In this embodiment, the pressurized air supply pump 6 is not limited and may be a member which can maintain the pressure of the air tank 7 .
[0022] The pressurized air valve 8 opens and closes a flow path of the pressurized air. The pressurized air valve 8 is provided in the second supply flow path 16 . The pressurized air valve 8 includes an electromagnetic valve and a solenoid thereof is connected to the control device 14 . The pressurized air valve 8 can be switched to a position V and a position W by sliding a spool. When the pressurized air valve 8 is at the position V, the second supply flow path 16 is closed. Then, the pressurized air is not supplied to the urea solution injection nozzle 2 . When the pressurized air valve 8 is at the position W, the second supply flow path 16 is opened. Then, the pressurized air is supplied to the urea solution injection nozzle 2 . The pressurized air valve 8 is not limited thereto and may alternatively be held at the position V or the position W by a driving motor or the like.
[0023] The urea solution supply pump 9 supplies a urea solution. The urea solution supply pump 9 is provided in the first supply flow path 15 . The urea solution supply pump 9 supplies the urea solution in a urea solution tank 10 via the first supply flow path 15 to the urea solution injection nozzle 2 at a predetermined flow rate. In this embodiment, the urea solution supply pump 9 is not limited and may be a member which can supply the urea solution at the predetermined flow rate.
[0024] The switching valve 11 switches a flow path of the urea solution. The switching valve 11 is provided at the downstream side of the urea solution supply pump 9 in the first supply flow path 15 . A drain pot 17 is connected via a flow path 15 a to the switching valve 11 . The switching valve 11 includes an electromagnetic valve and a solenoid thereof is connected to the control device 14 . The switching valve 11 can be switched to a position X and a position Y by sliding a spool.
[0025] When the switching valve 11 is at the position X, the first supply flow path 15 is closed and the urea solution injection nozzle 2 is communicated with the drain pot 17 . Then, the urea solution is not supplied to the urea solution injection nozzle 2 , and the urea solution in the first supply flow path 15 and the urea solution injection nozzle 2 at the downstream side of the switching valve 11 is discharged to the drain pot 17 .
[0026] When the switching valve 11 is at the position Y, the first supply flow path 15 is opened. Then, the urea solution is supplied to the urea solution injection nozzle 2 .
[0027] The temperature sensor 12 detects a temperature T of the atmosphere. The temperature sensor 12 is arranged at a position such as an engine room of a ship at which the temperature T of the atmosphere sucked by the engine 20 can be detected. This embodiment is not limited thereto, and any means is available if it can detect the temperature T of the atmosphere and transmit a detection signal of the temperature to the control device 14 .
[0028] The humidity sensor 13 detects an absolute humidity H of the atmosphere. The humidity sensor 13 is arranged at a position such as the engine room of the ship at which the absolute humidity H of the atmosphere sucked by the engine 20 can be detected. This embodiment is not limited thereto, and any means is available if it can detect the absolute humidity H and transmit a detection signal of the absolute humidity to the control device 14 . For example, it may alternatively be configured that a relative humidity is detected and a detection signal thereof is transmitted to the control device 14 so as to calculate the absolute humidity H based on the temperature T of the atmosphere.
[0029] The control device 14 controls the urea solution supply pump 9 , the switching valve 11 , the pressurized air valve 8 and the like. Various programs and data for controlling the urea solution supply pump 9 , the switching valve 11 , the pressurized air valve 8 and the like are stored in the control device 14 . The control device 14 may be configured by connecting a CPU, a ROM, a RAM, a HDD and the like by a bus, or may alternatively be configured by a one-chip LSI or the like. The control device 14 may be configured integrally with an ECU 22 which controls the engine 20 .
[0030] A map M is stored in the control device 14 . The map M converts an actual NOx discharge amount, which is an amount of NOx included in exhaust gas of the engine 20 driven with each rotation speed and each load under predetermined temperature and absolute humidity of the atmosphere, into a standard NOx discharge amount Ns, which is an amount of NOx with each rotation speed and each load under standard conditions (for example, 10.71 g/kg 25° C.), with a correction formula F which is known or a measured formula. Concretely, the actual NOx discharge amount of the engine 20 with optional rotation speed and load under the predetermined temperature and absolute humidity of the atmosphere is measured under each driving condition. Then, the actual NOx discharge amount is converted into the standard NOx discharge amount Ns under the standard conditions with the correction formula F based on temperature and absolute humidity of the atmosphere at the time of the measurement. The map M of the standard NOx discharge amount Ns made as the above is stored. In addition, the correction formula F is stored in the control device 14 .
[0031] The control device 14 is connected to the solenoid of the pressurized air valve 8 and can control opening and closing of the pressurized air valve 8 .
[0032] The control device 14 is connected to a driving motor of the urea solution supply pump 9 and can control an operation state of the urea solution supply pump 9 . Namely, by controlling the operation state of the urea solution supply pump 9 , the control device 14 can change optionally an addition amount Q of the urea solution added to the exhaust gas. The control device 14 is connected to the solenoid of the switching valve 11 and can control opening and closing of the switching valve 11 .
[0033] The control device 14 is connected to the temperature sensor 12 and can obtain a signal of the temperature T of the atmosphere detected by the temperature sensor 12 . The control device 14 is connected to the humidity sensor 13 and can obtain a signal of the absolute humidity H of the atmosphere detected by the humidity sensor 13 . A relative humidity can be detected and a detection signal thereof can be transmitted to the control device 14 so as to calculate the absolute humidity with the control device 14 using the temperature T of the atmosphere.
[0034] The control device 14 is connected to the ECU 22 and can obtain various kinds of information about the engine 20 obtained by the ECU 22 . Concretely, the control device 14 can obtain a rotation speed R of the engine 20 , which is detected by a rotation speed sensor 20 a of the engine 20 , via the ECU 22 . The control device 14 can obtain an output of a dynamo 23 , driven by the engine 20 , detected by a load sensor 23 a of the dynamo 23 as a load L of the engine 20 via the ECU 22 . The load L is not limited to the detection value of the load sensor 23 a and may alternatively be calculated from a rack position, a fuel injection amount or an actual rotation speed. The control device 14 may obtain various kinds of information about the engine 20 directly not via the ECU 22 .
[0035] The control device 14 is connected to an input device (not shown) and can obtain a signal about a target purification rate inputted from the input device and concentration of the urea solution. Alternatively, information about the target purification rate and the concentration of the urea solution can be inputted and defined previously.
[0036] The NOx catalyst 19 promotes deoxidization reaction of NOx. The NOx catalyst 19 is arranged inside the exhaust pipe 21 and at the downstream side of the urea solution injection nozzle 2 . The NOx catalyst 19 is configured honeycomb like and promotes reaction that ammonia generated by thermal hydrolysis of the urea solution reduces NOx included in the exhaust gas into nitrogen and water.
[0037] Next, an explanation will be given on the urea solution injection nozzle 2 of internal mixing type concretely referring to FIG. 2 . The type of the urea solution injection nozzle 2 is not limited to this embodiment and an external mixing type urea solution injection nozzle may alternatively be used. A fluid nozzle used for an air-less type exhaust purification apparatus which does not use pressurized air may alternatively be used.
[0038] As shown in FIG. 2 , the urea solution injection nozzle 2 has the double pipe 3 , the liquid nozzle 4 , the air nozzle 5 , and the like.
[0039] The double pipe 3 is a main component of the urea solution injection nozzle 2 and constitutes the flow path of the urea solution and the flow path of the pressurized air. One of sides of the double pipe 3 is arranged inside the exhaust pipe 21 and the other side (upstream side) thereof is arranged outside the exhaust pipe 21 . The downstream end of the double pipe 3 is arranged upstream the NOx catalyst 19 arranged inside the exhaust pipe 21 .
[0040] The double pipe 3 includes an outer pipe 3 b and an inner pipe 3 a arranged inside the outer pipe 3 b . A urea solution flow path 3 c which is a flow path of the urea solution is configured in the inner pipe 3 a . A gas flow path 3 d which is a flow path of the pressurized air is configured in a space between the inner pipe 3 a and the outer pipe 3 b . In a middle part of an outer side of the outer pipe 3 b , a connection part (not shown) which can be connected watertightly to the exhaust pipe 21 is configured. In downstream ends of the inner pipe 3 a and the outer pipe 3 b , a female screw part 3 e and a male screw part 3 f are formed respectively. In an upstream end of the double pipe 3 , a urea solution supply port 3 g communicated with the urea solution flow path 3 c and a gas supply port 3 h communicated with the gas flow path 3 d are configured.
[0041] The liquid nozzle 4 injects the urea solution. The liquid nozzle 4 is formed by a substantially cylindrical member and arranged downstream the double pipe 3 . One of ends (downstream end) of the liquid nozzle 4 is formed conically around the axis. At a center of the end, a projection part 4 a which is substantially cylindrical is formed so as to be projected axially. In the other end (upstream end) of the liquid nozzle 4 , a male screw part 4 b is formed so as to be projected axially. Furthermore, in an axial center part of the liquid nozzle 4 , a urea solution flow path 4 c is formed so as to penetrate axially the whole liquid nozzle 4 from the male screw part 4 b to the projection part 4 a . A middle part of the urea solution flow path 4 c is contracted diametrically so that an inner diameter of a downstream end of the urea solution flow path 4 c is formed smaller than an inner diameter of an upstream end of the urea solution flow path 4 c.
[0042] The male screw part 4 b of the liquid nozzle 4 is screwed to the female screw part 3 e of the double pipe 3 . Accordingly, the double pipe 3 is connected to the liquid nozzle 4 and the urea solution flow path 4 c is communicated with the urea solution flow path 3 c of the double pipe 3 . Then, the urea solution can be supplied from the urea solution flow path 3 c of the double pipe 3 to the urea solution flow path 4 c.
[0043] The air nozzle 5 injects the urea solution which is atomized. The air nozzle 5 is formed by a substantially cylindrical member. The air nozzle 5 is arranged downstream the liquid nozzle 4 so that one of ends (upstream end) of the air nozzle 5 touches the downstream end of the double pipe 3 . A flange part 5 a is firmed in a side surface of an upstream end of the air nozzle 5 . In an axial part of the air nozzle 5 , a hole which has a substantially conical diametrical contracted part contracted diametrically from a middle part toward the other side (downstream side) is formed penetratingly from the upstream end to the downstream end. An inner diameter of an upstream end of the hole is formed enough for the pressurized air to pass therethrough even if a downstream end of the liquid nozzle 4 is inserted into the upstream end of the hole. In an axial center part of a diametrical contracted side end of the diametrical contracted part, a mixing flow path 5 c of the urea solution is formed. In a downstream end of the air nozzle 5 , an injection port 5 e which is an opening of the mixing flow path 5 c is formed.
[0044] The air nozzle 5 is connected to the double pipe 3 by a nut 5 b . The downstream end of the liquid nozzle 4 is inserted into the hole of the upstream side of the air nozzle 5 (the mixing flow path 5 c ). At this time, a space is formed between the hole of the air nozzle 5 and the liquid nozzle 4 . The space is communicated as a gas flow path 5 d with the gas flow path 3 d of the double pipe 3 and the mixing flow path 5 c . Accordingly, the urea solution is supplied from the urea solution flow path 4 c of the liquid nozzle 4 to the mixing flow path 5 c , and the pressurized air is supplied from the gas flow path 5 d to the mixing flow path 5 c . Namely, the injection port 5 e can inject the urea solution by screwing the air nozzle 5 to the double pipe 3 .
[0045] According to the above, the urea solution injection nozzle 2 has the liquid nozzle 4 which injects the urea solution toward one of the sides (downstream side) and the air nozzle 5 , and injects the urea solution toward the NOx catalyst 19 . In this embodiment, in the urea solution injection nozzle 2 , the urea solution flow path 4 c , the gas flow path 5 d , and the mixing flow path 5 c are configured by the liquid nozzle 4 and the air nozzle 5 . However, the configuration is not limited thereto and the urea solution flow path 4 c , the gas flow path 5 d , and the mixing flow path 5 c may be configured respectively.
[0046] An explanation will be given on an operation mode of the pressurized air valve 8 and the switching valve 11 referring to FIG. 1 .
[0047] As shown in FIG. 1 , the air tank 7 is connected to the gas supply port 3 h of the urea solution injection nozzle 2 via the pressurized air valve 8 by the second supply flow path 16 .
[0048] As mentioned above, normally, the pressurized air valve 8 is held at the position V. In this case, since the second supply flow path 16 is closed, the pressurized air is not supplied to the gas supply port 3 h of the urea solution injection nozzle 2 .
[0049] When the control device 14 energizes the solenoid of the pressurized air valve 8 , the pressurized air valve 8 is switched from the position V to the position W. In this case, since the second supply flow path 16 is opened, the pressurized air is supplied to the gas supply port 3 h of the urea solution injection nozzle 2 .
[0050] When the control device 14 stops the energization to the solenoid of the pressurized air valve 8 , the pressurized air valve 8 is switched to the position V. In this case, since the second supply flow path 16 is closed, the pressurized air is not supplied to the gas supply port 3 h of the urea solution injection nozzle 2 .
[0051] As shown in FIG. 1 , the urea solution tank 10 is connected to the urea solution supply port 3 g of the urea solution injection nozzle 2 via the urea solution supply pump 9 and the switching valve 11 by the first supply flow path 15 .
[0052] As mentioned above, normally, the switching valve 11 is held at the position X. In this case, since the first supply flow path 15 is closed, the urea solution is not supplied to the urea solution supply port 3 g of the urea solution injection nozzle 2 . The urea solution supply port 3 g of the urea solution injection nozzle 2 is atmosphere-opened in the drain pot 17 via the flow path 15 a.
[0053] When the control device 14 energizes the solenoid of the switching valve 11 , the switching valve 11 is switched to the position Y. In this case, since the first supply flow path 15 is opened, the urea solution is supplied to the urea solution supply port 3 g of the urea solution injection nozzle 2 . Since the communication with the drain pot 17 is cut off, the urea solution supply port 3 g of the urea solution injection nozzle 2 is not atmosphere-opened.
[0054] When the control device 14 stops the energization to the solenoid of the switching valve 11 , the switching valve 11 is switched to the position X. In this case, since the first supply flow path 15 is closed, the urea solution is not supplied to the urea solution supply port 3 g of the urea solution injection nozzle 2 . Since the communication with the drain pot 17 is permitted, the urea solution supply port 3 g of the urea solution injection nozzle 2 is atmosphere-opened in the drain pot 17 .
[0055] An explanation will be given on an operation mode of the urea solution injection nozzle 2 referring to FIGS. 1 and 2 .
[0056] As shown in FIG. 1 , when the supply (injection) of the urea solution to the inside of the exhaust pipe 21 is started, the control device 14 switches the switching valve 11 to the position Y so that the urea solution is supplied to the urea solution supply port 3 g of the urea solution injection nozzle 2 (the double pipe 3 ). The urea solution is injected from the projection part 4 a of the liquid nozzle 4 to the mixing flow path 5 c of the air nozzle 5 via the urea solution flow path 3 c of the double pipe 3 and the urea solution flow path 4 c of the liquid nozzle 4 .
[0057] In this state, the control device 14 switches the pressurized air valve 8 to the position W so that the pressurized air is supplied to the gas supply port 3 h of the urea solution injection nozzle 2 (the double pipe 3 ). As shown in FIG. 2 , the pressurized air is injected at a predetermined pressure via the gas flow path 3 d of the double pipe 3 and the gas flow path 5 d of the air nozzle 5 to the mixing flow path 5 c of the air nozzle 5 . As a result, the urea solution collides with the pressurized air inside the mixing flow path 5 c of the air nozzle 5 and is atomized, and then injected via the injection port 5 e of the air nozzle 5 .
[0058] As shown in FIG. 1 , when the supply (injection) of the urea solution to the inside of the exhaust pipe 21 is stopped, the control device 14 switches the switching valve 11 to the position X so that the supply of the urea solution to the urea solution supply port 3 g of the urea solution injection nozzle 2 (the double pipe 3 ) is stopped. Accordingly, the urea solution supply port 3 g of the double pipe 3 is atmosphere-opened via the first supply flow path 15 and the switching valve 11 .
[0059] An explanation will be given on a mode of calculation of the addition amount of the urea solution referring to FIG. 3 .
[0060] The control device 14 obtains the signal of the temperature T of the atmosphere from the temperature sensor 12 and obtains the signal of the absolute humidity H of the atmosphere from the humidity sensor 13 . The control device 14 obtains the signal of the rotation speed R of the engine 20 from the rotation speed sensor 20 a and obtains the signal of the load L of the engine 20 from the load sensor 23 a . The control device 14 calculates an actual NOx discharge amount Nr based on the obtained information and controls the operation state of the urea solution supply pump 9 (see FIG. 1 ).
[0061] As shown in FIG. 3 , the control device 14 controls the operation state of the urea solution supply pump 9 with below steps.
[0062] Firstly, at a step S 110 , the control device 14 obtains the signal of the temperature T of the atmosphere from the temperature sensor 12 and obtains the signal of the absolute humidity H of the atmosphere from the humidity sensor 13 . The control device 14 obtains the signal of the rotation speed R of the engine 20 from the rotation speed sensor 20 a and obtains the signal of the load L of the engine 20 from the load sensor 23 a.
[0063] At a step S 120 , the control device 14 calculates the standard NOx discharge amount Ns, which is an amount of NOx discharged from the engine 20 driven with the rotation speed R and the signal of the load L under standard conditions, from the signal of the rotation speed R and the signal of the load L of the engine 20 with the map M.
[0064] At a step S 130 , the control device 14 calculates an actual NOx discharge amount Nr, which is an amount of NOx discharged from the engine 20 driven with the rotation speed R and the signal of the load L under the temperature T and the absolute humidity H of the atmosphere, from the standard NOx discharge amount Ns corresponding to the rotation speed R and the signal of the load L calculated at the step S 120 and the signal of the temperature T and the signal of the absolute humidity H of the atmosphere with the correction formula F by inverse operation. Namely, the actual NOx discharge amount Nr which is necessary to set the amount of NOx discharged from the engine 20 , which is driven with the rotation speed R and the signal of the load L under the temperature T and the absolute humidity H of the atmosphere, to the standard NOx discharge amount Ns is calculated with the correction formula F.
[0065] At a step S 140 , the control device 14 determines the addition amount Q of the urea solution, which is necessary to reduce the actual NOx discharge amount Nr from the target purification rate and the concentration of the urea solution which are set optionally.
[0066] At a step S 150 , the control device 14 controls the operation state of the urea solution supply pump 9 so as to supply the addition amount Q of the urea solution in the urea solution supply pump 9 to the exhaust gas. Subsequently, the control device 14 returns to the step S 110 .
[0067] Accordingly, as shown in FIG. 4 , in the case in which the addition amount Q of the urea solution is Q 1 while the actual NOx discharge amount Nr is Nr 1 , when the actual NOx discharge amount Nr is decreased to Nr 2 ′, NOx is decreased more than the target purification rate (a two-dot chain line in FIG. 4 ) (over-denitration) (see A′). Then, by the above control, the decrease of the actual NOx discharge amount Nr to Nr 2 ′ is calculated, and the urea solution supply pump 9 is controlled so as to set the addition amount Q of the urea solution to a suitable addition amount Q 2 ′. Furthermore, when the actual NOx discharge amount Nr is decreased to Nr 2 , NOx is decreased more than the target purification rate (over-denitration) and ammonia exceeding a theoretical equivalent (a dashed line in FIG. 4 ) and remaining is discharged outside the exhaust pipe 21 (ammonia slip). Then, by the above control, the decrease of the actual NOx discharge amount Nr to Nr 2 is calculated, and the urea solution supply pump 9 is controlled so as to set the addition amount Q of the urea solution to a suitable addition amount Q 2 . When the actual NOx discharge amount Nr is increased to Nr 3 , denitration shortage that NOx cannot be decreased to the target purification rate occurs (see a point B). Then, by the above control, the increase of the actual NOx discharge amount Nr to Nr 3 is calculated, and the urea solution supply pump 9 is controlled so as to set the addition amount Q of the urea solution to a suitable addition amount Q 3 .
[0068] As the above, the exhaust purification apparatus 1 , in which ammonia is added as a reducing agent to the exhaust gas of the engine 20 which is an internal combustion engine so as to reduce nitrogen oxide in the exhaust gas, has the temperature sensor 12 detecting a temperature T of the atmosphere, the humidity sensor 13 detecting the absolute humidity H or the relative humidity of the atmosphere, and the control device 14 calculating the addition amount of the urea solution. The map M, which converts the actual NOx discharge amount Nr of the engine 20 driven with each rotation speed and each load under predetermined temperature and absolute humidity of the atmosphere into the standard NOx discharge amount Ns of the engine 20 with each rotation speed and each load under the standard conditions with the correction formula F is stored in the control device 14 . The rotation speed sensor 20 a which is a rotation speed detection means detecting the rotation speed of the engine 20 and the load sensor 23 a of the dynamo 23 which is a load detection means detecting the load of the engine 20 are connected to the control device 14 . The standard NOx discharge amount Ns corresponding to the rotation speed R detected by the rotation speed sensor 20 a and the load L detected by the load sensor 23 a is calculated with the map M. The standard NOx discharge amount Ns is converted into the actual NOx discharge amount Nr of the rotation speed R and the load L under the temperature T of the atmosphere detected by the temperature sensor 12 and the absolute humidity H of the atmosphere detected by the humidity sensor 13 with the correction formula F by inverse operation. The addition amount Q of the urea solution is calculated based on the actual NOx discharge amount Nr.
[0069] According to the configuration, the actual NOx discharge amount Nr based on the characteristic of the engine 20 can be calculated while considering the temperature T of the atmosphere and the absolute humidity H of the atmosphere which influence the NOx discharge amount greatly. Accordingly, the urea solution of the suitable amount can be added without measuring directly the actual NOx discharge amount Nr with a NOx sensor.
[0070] The addition amount Q is calculated in consideration of the target purification rate and the concentration of the urea solution.
[0071] According to the configuration, the addition amount Q can be adjusted corresponding to the operating condition. Accordingly, the urea solution of the suitable amount can be added without measuring directly the actual NOx discharge amount Nr with a NOx sensor.
INDUSTRIAL APPLICABILITY
[0072] The present invention can be used especially for an exhaust purification apparatus for a ship.
DESCRIPTION OF NOTATIONS
[0000]
1 exhaust purification apparatus
12 temperature sensor
13 humidity sensor
14 control device
20 engine
20 a rotation speed sensor
23 a load sensor
R rotation speed
W load
Ns standard NOx discharge amount
Nr actual NOx discharge amount
Q addition amount | The purpose of the present invention is to provide an exhaust purification device that is capable of adding an appropriate amount of urea solution without the need to directly measure the NOx emissions amount using an NOx measuring means. The exhaust purification device uses urea solution as a reducing agent for reducing nitrogen oxides within exhaust, and is provided with a temperature sensor, a humidity sensor, and a control device. A map is stored in the control device, and in said map the real NOx emissions amount for each rotation speed and each load of an engine occurring at a predetermined air temperature and a predetermined absolute humidity are converted using a correction formula into a reference NOx emissions amount for each rotation speed and each load of the engine while in a standard state. Using the map, the control device calculates a reference NOx emissions amount that corresponds to the rotation speed detected by a rotation speed sensor and to the load detected by a load sensor, uses the correction formula to convert the reference NOx emissions amount into the real NOx emissions amount occurring at an air temperature and an absolute humidity, and calculates a urea solution addition amount. | 5 |
RELATED APPLICATIONS
[0001] None
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] This invention pertains to a shoe shining device, and more particularly to a device incorporating a shining cloth, the device being compact so that it can easily be stored and packed but readily deployable for use.
[0004] 2. Description of the Prior Art
[0005] Clean and shiny shoes are the mark of a professional, well groomed person, and accordingly, various shoe shining kits are readily available. The kits include separate cans of shoe wax, a variety of brushes, and other similar tools. Some kits may also include sprays which disperse waxy substances. These kits are too bulky to be carried easily by travelers. This is particularly true for business travelers who often try to pack everything into carry-on luggage.
[0006] Some hotels provide a small round sponge for shoe shining, but this sponge is too small and inadequate to produce properly shined shoes.
SUMMARY OF THE INVENTION
[0007] A device for shining constructed in accordance with this invention includes an elongated housing with a longitudinal slot. A sheet made of a material suitable for shining shoes and having a generally rectangular shape has one edge secured to a mechanism inside the housing. The second end extends through the slot and can be used to pull the sheet out at least partially so that it can be used to clean shoes. A mechanism is provided inside the housing that locks the sheet while its outside, and then when activated, it automatically retracts the sheet into the housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a side elevational view of a show shine device constructed in accordance with this invention;
[0009] FIG. 2 shows a side view of the device of FIG. 1 with a portion of the housing remove to render its interior visible;
[0010] FIG. 3 shows a top view of the device; and
[0011] FIG. 4 shows an orthogonal view of an alternate embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] As shown in the Figures, a device 10 constructed in accordance with this invention includes a generally cylindrical housing 12 made of a metal, a plastic material, cardboard, etc. Typically the housing may be about 5-7 in. long and have a diameter in the range of ½ to 1 in. The housing is formed with a lateral wall 14 and end walls 16 and 18 . A longitudinal slot 20 is formed on the lateral wall 14 , extending substantially along the length of the housing 10 .
[0013] Disposed in the housing is a shoe shining sheet 22 made of paper, a woven or non-woven fabric, or other materials. Preferably, the sheet 22 is soft and pliable so that it does not scuff the shoes during cleaning. Optionally, the sheet 22 may be impregnated at least on one side with an appropriate waxy substance. The sheet includes two lateral edges 24 , 26 and two ends 28 , 30 . End 28 is the free end that is preferably disposed outside the housing. To insure that the end 28 stays outside, the sheet may be provided with an outside stop 31 formed so that the thickness is effectively increased. The outside stop 31 may be made of fabric, cardboard or other material, or may be implemented by folding a portion of the sheet 22 over itself and securing the folded portion by sewing or gluing.
[0014] As best seen in FIG. 1 , the wall 14 and/or other portions of the housing could be used to provide advertising or other promotional material. Advertising material or other text and graphical images may also be provided on the sheet 22 itself.
[0015] Inside the housing 12 there is provided a mechanism 32 for selectively rolling the sheet 12 up and to allow it to be played out and withdrawn from the housing. For example, the mechanism 32 may be implemented by a mandrel 34 housing a coil spring 36 , with a clutch 38 at one end. This type of device is well known, for example, in window shades.
[0016] Normally, the sheet 22 is disposed within the housing 12 so that only its end 28 is showing in the slot 20 . Outside stop 31 insures that the sheet is not drawn inside the housing 12 . Within the housing 12 the sheet 22 is wound about the mandrel 34 with end 30 secured to the mandrel 34 and is biased in this position by spring 36 . To use the device, a person pulls out the sheet 22 from the housing 12 . While intermediate positions may be provided, it is preferable that the whole sheet be pulled out or extended as shown. The clutch 38 latches unto the mandrel 34 to insure that sheet stays in the extended position and can be used by a person to clean and shine his shoes. When he is done, the person releases the sheet 22 so that the sheet is automatically pulled back into the housing 12 . This may be accomplished in a number of ways. In one embodiment, the person pulls on the sheet 22 slightly and then releases it. This action causes the clutch 38 to disengage from the mandrel and allow the mandrel to rotate and pulls the sheet 22 in. In another embodiment, an external button (not shown) may be provided to disengage the mandrel and, under the action of the spring, cause the sheet 22 to be pulled back. An inside stop 40 is positioned near end 30 . As the sheet 22 is pulled out of the housing, the stop 40 comes into contact with the inner edges of the slot 20 and prevents the sheet to be inadvertently removed or pulled out of the housing 12 . The stop 40 may be made in the same way as the rib 32 .
[0017] Advantageously the device 10 is small enough so that it can be stored easily in a purse, brief case, etc. However, once it is removed, its sheet can be deployed rapidly and easily to allow a person to use it. Moreover, once a person is finished, the sheet 22 is quickly and automatically drawn into the housing and stored there until the next use. The device can be made easily for a relatively small cost.
[0018] In an alternative embodiment of the invention shown in FIG. 4 spring 36 disposed in the mandrel is replaced by a planar coil spring 40 similar to the ones used in watches is disposed at one end of the mandrel to bias the same.
[0019] Numerous modifications may be made to the invention without departing from its scope as defined in the appended claims. | A shoe shine device includes cylindrical housing sized to fit into a purse or briefcase. A sheet of pliable material suitable for shining shoes can be selectively withdrawn from the housing. After use, the sheet is automatically retracted into the housing. | 0 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. provisional application Ser. No. 60/807,949, filed Jul. 21, 2006, which is incorporated herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention is directed at measuring and recording the conditions inside a chamber containing a mixture of cloth items and fluid. The invention has particular utility in characterizing the motion of cloth items in an automatic washing machine, and providing information to help understand the mechanisms at work driving that motion.
[0004] 2. Description of the Related Art
[0005] In the field of clothes washing machine technology, new machines are being designed to increase electrical efficiency, reduce water consumption, and improve cleaning effectiveness. These improvements require a significant departure from current technology, and considerable effort is underway to design new machines.
[0006] In the washing machine design process, reliable measurement and observation of the conditions inside the wash chamber provide important information about the effect of various configurations, features, operational parameters, and settings of the washing machine. This information may allow the designer to use a closed-loop iterative approach in which design changes are based on reliable measured and observed effects.
[0007] In many washing machine design environments, direct visual observation is used, along with some basic measurement of fluid flows, rotational speed, power, timing, and cleaning performance. However, there is currently no method in widespread use to accurately measure the circulation of cloth items and fluids and driving forces of cloth items and fluid in an automatic washing machine. Although some methods to measure the circulation and driving forces exist, the known methods provide limited information, disturb the operation of the machine, or otherwise modify the parameters it is desired to measure. A method and apparatus that could measure the circulation and driving forces without significantly disturbing the operation would be a valuable complementary tool in the design process because it would provide more information to the designer about the nature of the physical processes taking place in the wash chamber.
SUMMARY OF THE INVENTION
[0008] The present invention addresses the foregoing needs by providing a method by which the driving forces and consequent motion of the cloth-fluid mixture within a chamber may be determined. Some of the state parameters that may be measured and recorded include, but are not limited to: position of cloth items, velocity of cloth items, acceleration of cloth items, circulation rate of cloth items, frictional forces between cloth items and chamber surfaces, fluid flow direction, fluid velocity, and fluid acceleration.
[0009] In one aspect of the invention, contact sensors can be used to measure the times and locations at which a pre-determined “target cloth” comes in contact with the inner surface of the wash chamber. In one embodiment, the contact sensors are comprised of discrete copper strips laid down on the metallic chamber surfaces with insulating material between the copper strips and the surfaces. The copper strips are supplied a voltage through a pull-up resistor. This strip voltage is referenced to the metallic inner surface of the wash chamber, and is continually monitored. An electrically conductive target cloth is added to the wash chamber, such that when the target cloth contacts the edge of the contact strip, and overlaps the insulator, it provides increased electrical conduction between the strip and the metallic surface. Contact is then detected as a drop in voltage of the strip to a value lower than some threshold voltage that depends on the wash fluid and on the conductivity of the target cloth.
[0010] In another aspect of the invention, sensors may be used to measure the rotational position, velocity, and acceleration of various components within the washing machine. In one embodiment, Hall effect sensors are used to measure rotation of the wash basket with respect to the wash bucket, and rotation of the impeller with respect to the wash basket. This information can be combined with the contact sensor data and with video of the top of the wash chamber to calculate the complete target cloth trajectory within the chamber.
[0011] In another aspect of the invention, friction sensors may be used to measure the frictional forces between the cloth items and the surfaces within the wash chamber. These surfaces may be on an impeller, agitator, or wash basket, among other surfaces within the chamber. In one embodiment, the friction sensors may be added to a component by cutting a small section of material out of the surface of the component, and reinstalling it very near its original position by mechanically connecting it with a small beam or attachment rod that extends from the cut section to a rigid structure that is part of the component. Two strain gauges mounted on the attachment rod, electrically wired in a half bridge configuration, may be used to measure bending of the rod. This bending can be related to forces tangential to the surface of the sensor (frictional forces) by calibrating the system. Similarly, in another embodiment, the sensor described above as a friction sensor may be used to measure normal forces between the cloth items and the surface by measuring the compressive response of the rod with strain gages wired in a variety of bridge configurations.
[0012] In another aspect of the invention, fluid flow direction and velocity may be determined using a tracer fluid injection system. In one embodiment, an output channel of the microcontroller is used to activate a device that injects dye into the chamber via a flush-mounted port in the surface of an interior component. By capturing video during the wash cycle, and knowing the time at which the dye was released, an estimate of fluid flow direction and velocity is determined. In another embodiment, the dye may be replaced with a conductive tracer fluid, and specialized electrical sensors, or the contact sensors themselves, can be used to track the motion of the tracer fluid, which will flow predominantly along with the main wash fluid.
[0013] In another aspect of the invention, any signals measured by any of the aforementioned sensors or by any other sensors may be communicated out of the washing machine and into an external data acquisition and control computer. These signals may be communicated using mechanical contacts such as a slip ring, or by using wireless technology. Two-way communication between the data acquisition and control computer and the machine will permit the data acquisition and control computer to also control active devices embedded in the machine, such as the dye injectors previously mentioned.
[0014] There are a large number of possible types of motions and circulations of cloth items that this invention can measure. Some of the possible motions that can be measured are: toroidal and inverse toroidal rollover of cloth items, azimuthal motion or circulation of cloth items, and oscillations of cloth items (in any direction or coordinate).
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a washing machine configured for cloth motion testing embodying the present invention.
[0016] FIG. 2 is a block diagram of an instrumentation system for measuring cloth motion in a washing machine.
[0017] FIG. 3 is a washing machine configured for friction sensing according to a second embodiment of the present invention.
[0018] FIG. 4 is a block diagram showing a friction measurement system.
[0019] FIG. 5 is an embodiment of contact sensors in a washing machine.
[0020] FIG. 6 is an embodiment of a contact sensing circuit using for detecting cloth motion in a washing machine.
[0021] FIG. 7 a is an embodiment of a rotational measurement system.
[0022] FIG. 7 b is an embodiment of a rotational measurement system.
[0023] FIG. 8 is an embodiment of a friction measurement system.
[0024] FIG. 9 is the friction measurement system of FIG. 8 mounted in an impeller blade of a washing machine.
[0025] FIG. 10 illustrates a technique for calibrating the friction sensor.
[0026] FIG. 11 illustrates an embodiment of a dye injection system.
DETAILED DESCRIPTION
[0027] The present invention comprises a system and method for measuring cloth motion and forces on cloth items within an automatic washing machine chamber, or more generally, within a chamber containing a mixture of cloth items and a fluid. The invention in whole or in part can be used in any type of clothes washing machine.
Overall System
[0028] A measurement system for measuring cloth motion and forces on cloth items within a washing machine will now be described in detail with initial reference to the illustrative embodiment of the invention as shown in FIGS. 1 and 2 . A washing machine 10 is provided having a measurement system 100 . A complete measurement system 100 may be constructed that includes a sensing system 110 and a data acquisition and control computer 102 . The measurement system 100 may be configured to communicate information from the sensing system 110 to the data acquisition and control computer 102 . In one embodiment, shown in FIGS. 1 and 2 , sensing systems 110 a , 110 b , and 110 c are installed in a washing machine chassis 12 , a wash basket 14 , and an impeller 16 , respectively, in order to measure cloth motion. The sensing systems 110 may include one or more sensors 112 , microcontrollers 114 , communication devices, batteries, and antennae. Signals from the sensing systems are communicated to a data acquisition and control computer 20 via a combination of wired and wireless protocol. The data acquisition and control computer 20 is configured to record the signals from the sensing systems, and has the ability to issue commands to the sensing systems in the washer to affect the cloth-cleaning solution mixture in some way, or to effect the washer operation in some way. As one of skill in the art is aware, any number of sensing systems may be provided in order to accomplish various measurements in a washing machine. One or more of the sensing systems may be provided without changing the scope of the invention.
[0029] Any necessary electronic equipment may be installed in small spaces or non-intrusive areas such as within towers, impeller blades, or other protrusions. Alternately, it may be possible in some cases to route wiring out of the chamber to small remote computers, or to mechanical contacts that enable communication between the sensors and actuators and the data acquisition and control system.
[0030] Another embodiment of a complete measurement system is shown in FIGS. 3 and 4 . In this embodiment, frictional forces between cloth items and the impeller surface are measured.
Contact Sensors
[0031] Contact sensors can be used to measure the times and locations at which a pre-determined “target cloth” comes in contact with the inner surface of the wash chamber. In one embodiment of a contact measurement system 30 , as shown in FIG. 5 , the contact sensors are comprised of a plurality of discrete copper strips 32 laid down on the metallic chamber surfaces with insulating material between the copper strips and the chamber surfaces. As shown in FIG. 5 , the copper strips 32 may be provided on the inner walls of the wash basket 14 and the floor of the wash basket 22 . The copper strips 32 are supplied a voltage Vs through a pull-up resistor R, as shown in FIG. 6 . This strip voltage V is referenced to the metallic surface, and is continually monitored. A conductive target cloth is selected, such that when the target cloth contacts the edge of the contact strip 32 , and overlaps the insulator, it provides a conduction path between the strip and the metallic surface. Contact is then detected as a drop in voltage, V, of the strip to a value lower than some threshold voltage that depends on the wash fluid and on the conductivity of the target cloth.
[0032] A wide range of supply voltages, Vs, may be used. However, very high voltages may lead to corrosion of the contact sensors or of the surfaces of the wash basket, and very low voltages may be more difficult to measure. Low voltages (perhaps down to fractions of a Volt) and higher voltages (perhaps up to tens of Volts) may yield good results. Vs near 5 Volts has been demonstrated to produce a consistently measurable signal while limiting the corrosion rate of copper contact strips to a tolerable level.
[0033] Introduction of cleaning solution may cause the contact sensor voltage, V, to drop due to the conductivity of the solution itself. When using Vs=5 V and a 1 kOhm resistor, the cleaning solution may cause the contact sensor voltage to drop as low as 0.3 Volts. Ideally, a target cloth will have much higher conductivity than the cleaning solution, however. Therefore, a threshold voltage of approximately 0.25 Volts may then be used as criteria for detecting “contact” between a target cloth and a contact sensor.
[0034] The contact sensors may comprise very thin strips of copper tape 32 , preferably having a thickness of about 0.005 inches. The thin strips of copper may be overlying strips of very thin insulating tape 33 , preferably having a thickness of about 0.004 inches, for a total sensor height of about 0.009 inches. These sensor heights are small enough to be considered non-intrusive for most testing purposes. In other words, at these heights, they will not significantly change or disturb the natural behavior of the washer. Alternatively, the contact sensors may be dots, patches, grid patterns, or other configurations.
[0035] The contact sensors may be arranged in a grid so that the position of the target cloth may be determined in two dimensions. For example, the contact sensors may be arranged circumferentially and radially, at pre-determined intervals of each. Then, an estimate of target cloth position may be obtained using the “last known” radial and circumferential positions.
[0036] In using radial contact sensors to estimate the position of a target cloth, the radial contact sensors may be installed on rotating parts. Therefore, their positions may not be constant in time in the inertial frame, and must be adjusted for the amount of rotation they have undergone since the start of the test. This conversion may be accomplished by adding the initial position at the start of the test to the angular position of the given contact sensor at the point of contact. The initial position may be identified by observation or video, while the angular position may be calculated from the rotation sensor signal, as described in the following section.
[0037] Once all of the contact occurrences have been identified in space and time, the positions can be plotted versus time to show the trajectory of the target cloth in the wash chamber. If the target cloth is designed to be similar to an ordinary cloth item, this trajectory is one that may be expected for an ordinary cloth item in the machine tested.
[0038] In another embodiment of the contact sensors, the cloth items do not need to completely close the circuit between the contact sensor and the metallic surface of the wash chamber or ground. In this embodiment, the contact sensors may electrically sense contact with the target cloth through a variety of methods. One such method would be to use a target cloth that generates an AC signal or periodic voltage that is directly detectable by the contact sensors.
[0039] In another aspect of the invention, the target cloth includes a plurality of metallic elements, such as strips, patches, dots, or grids attached thereto and acts as the sensor. The plurality of metallic elements produce identifying electrical signals that are detected by the target cloth and either recorded or transmitted to the outside computer. The identifying electrical signals may be, for example, electrical pulse trains that are distinct for each strip.
Rotation Sensors
[0040] Using the measurements of the times and locations at which a target cloth comes into contact with the inner surface of the wash chamber, and knowing the initial positions of the components, the location, velocity, and acceleration of any point on the impeller or wash basket may be estimated at any time during the test. This can be useful for reconstructing the absolute position of any contact indications, allowing the target cloth trajectory to be calculated from the contact sensor and component position data.
[0041] One embodiment of a rotation measurement system 40 based on Hall effect sensors 42 is shown in FIGS. 7 a and 7 b . It comprises at least two Hall effect sensors spaced by approximately 10 degrees near the perimeter of a rotating component, an impeller in this case. The Hall effect sensors 42 may be placed on the underside of the impeller 16 . The Hall effect sensors 42 pass near a plurality of magnets 44 installed in the component for which relative rotation measurement is desired, in this case a wash basket. As shown in FIG. 7 b (with the impeller removed), the magnets 44 may be arranged in N-S, S-N, N-S, etc. pairs. Thus, as the impeller rotates, the sensors return an alternating +5V and 0V signal as they pass from pair to pair. The rate at which the signal changes is directly related to the angular velocity of the rotating component with respect to the fixed component having magnets. In addition, the direction of rotation may be determined by the leading or lagging of one Hall effect sensor with respect to the next.
Friction Sensors
[0042] Referring again to FIG. 3 , a measurement of the frictional forces between the wash chamber 114 and the cloth items may be acquired by an electromechanical friction sensor 212 . The friction sensor 212 may be used to measure the friction on any portion of the surface of the wash chamber, provided there is enough empty space below the surface to accommodate the components of the sensor. One embodiment of a friction sensor 212 is shown in FIG. 8 . The friction sensor 212 may include a slug 216 , which is a portion of the original surface of the wash chamber, a rod 218 , a mounting plate 220 , and a pair of strain gages 222 wired in a half-bridge circuit. The slug 216 is produced by cutting and removing a portion of the surface of the wash chamber. In previous practice, the diameter of the slug was close to that of an American dime. The slug 216 may be cut from the top surface of an impeller blade used in a washing machine. To cut the slug, it is desirable to use a technique that does not produce burrs or other features that may influence the frictional interaction between the cloth items and the surface of interest. One such technique is electric discharge machining.
[0043] In the embodiment of the friction sensor shown in FIG. 8 , friction may be measured on the surface of an impeller blade 116 in a washing machine. The slug 216 is mounted on a rod 218 and mounting plate 220 such that the surface of the slug 216 is conformal with the surface from which it was cut. The strain gages 222 a and 222 b are mounted on the surface of the rod, coaxial with each other and the rod, and offset 180-degrees from each other along the circumference of the cross-section of the rod. A half-bridge circuit of strain gages produces a non-zero electrical signal only when the two gages detect differing strains. FIG. 9 shows this embodiment from the underside of an impeller instrumented with a friction force sensor. The strain gages are electrically wired in a half-bridge circuit.
[0044] Mounting the slug conformal with the surface from which it was cut ensures that the gap between the slug and the surface does not significantly affect the frictional forces to be measured. One undesired effect is that cloth items may engage the machined edge of the slug and produce forces that are unrepresentative of frictional forces applied to the surface of interest. To show that this effect is not present, a series of tests can be executed. In the tests, the machine is operated with cloth items in the wash chamber and the mass of cloth items in the chamber is varied. If the frictional forces scale linearly with the mass of cloth items in the chamber, the forces measured by the sensor are frictional.
[0045] A frictional force applied to the surface of the slug 216 causes the rod 218 to deflect in a direction tangential to the surface of the slug 216 . If the deflection of the rod 218 has a component parallel to a straight line between the centers of the gages 222 , one gage will be compressed and the other gage will be extended. These differing strains produce a non-zero electrical signal, indicating the presence of a frictional force. For a range of forces, the magnitude of the frictional force is linearly proportional to the amount of deflection of the rod 218 and, therefore, to the signal produced by the strain gage circuit.
[0046] With the strain gages 222 wired in a half-bridge, a non-zero signal is produced only if the force applied to the surface of the slug 216 has a component parallel to a straight line between the centers of the strain gages. A force coaxial with the long axis of the rod 218 , for example, will produce a zero signal because the strain gages will be in equal tension or equal compression. Likewise, a force tangential to the surface of the slug 216 but perpendicular to a straight line between the centers of the strain gages 222 will produce a zero signal because the strain gages will experience equal states of strain. In theory, a force applied to the surface of the slug 216 parallel to but not coaxial with the long axis of the rod 218 would produce a non-zero signal because such a force would produce a moment and consequent bending in the rod 218 . However, if the slug 216 is of sufficiently small size, such moments and consequent non-zero signals are negligible.
[0047] To measure frictional forces in two perpendicular directions tangential to the surface of the slug 216 , an additional pair of strain gages can be mounted offset 90 degrees around the circumference of the cross-section of the rod relative to the first pair of gages and wired in an additional half-bridge circuit.
[0048] A calibration procedure may be used to quantify the relationship between the magnitude of the electrical signal produced by the strain gage circuit and the magnitude of the frictional force. One such calibration procedure is shown in FIG. 10 . As shown, one end of a thin thread 224 is adhered to the surface of the slug 216 with the surface of the slug oriented such that gravity is parallel to the long axis of the rod. An object of known mass 226 is attached to the opposite end of the thread 224 . The thread 224 is extended tangential to the surface of the slug 216 and over a lubricated pulley 228 such that the object of known mass 226 hangs freely, applying its weight tangentially to the surface of the slug. By employing a range of known masses, the relationship between the magnitude of the electrical signal and the force applied to the slug can be identified.
[0049] The description above is applicable to the measurement of frictional forces, forces acting tangential to the surface of interest. The sensor can also be used to measure forces acting normal to the surface of interest. To accomplish this, four strain gages wired in a full-bridge circuit can be used. Alternatively, two gages in a half-bridge circuit with the gages wired in opposing arms of the bridge, or a single gage in a quarter-bridge circuit, can also be used. None of the other components of the sensor need to be altered from the description above in order to measure forces normal to the surface of interest.
Fluid Flow Sensing System
[0050] A fluid flow sensing system 50 may be installed in the washer to determine the direction and velocity of the fluid flow. In one embodiment, as shown in FIG. 11 , a dye injection system 52 receives a command from either a microcontroller or an outside computer to inject a fluid into the washer at a specific location. The event may be captured with video. The direction of flow of the fluid may be determined from the video, which can be synchronized with the dye pulse.
[0051] In one embodiment, the dye injection system consists of a spring-loaded syringe 54 that can be filled with dye through a check valve 56 via a loading port 62 . Once full, the system is loaded and the test begins. A microcontroller receives a signal from an outside computer to inject dye, and then actuates a solenoid valve 58 , which allows the dye to quickly flow into the washer from an emission port 60 flush with the wash chamber surface.
[0052] In another embodiment, a tracer fluid may be injected either in place of or in conjunction with the dye. This tracer fluid may be a conductive liquid that can be detected by other sensors in the wash chamber, or by monitoring contact sensor voltages. In this embodiment, velocity of the fluid may be determined by measuring the transit time between detection of the conductive fluid by adjacent sensors.
Communication System
[0053] In an embodiment of the present invention, microcontrollers may be embedded within the workings of the machine to acquire signals and to control the various sensing systems. The microcontrollers communicate with a computer 20 outside the machine that records the data and commands the smaller electronic units embedded in the machine.
[0054] The communication channels between the microcontrollers and the outside computer can be accomplished using a number of technologies. For example, the communication may be via a wireless link, such as Bluetooth. Since the wireless link must transmit and receive the signals through some amount of cleaning solution, relatively high transmit powers must be used. Additionally, antenna matching should be undertaken to ensure the best link possible given the selected transmit power. Commercially available Class 1 Bluetooth transmitters have been found to successfully transmit through the cleaning solution when used with patch antennas also embedded within the washing machine.
[0055] Other communication channels that may also work are hard-wire (using slip rings if necessary to communicate between parts with relative concentric rotation), optical links such as IRDA, and many other radio frequencies and protocols.
[0056] Buffering of signal data in the microcontrollers may also be used to store data during periods when communication cannot be accomplished. The buffering capacity may range from milliseconds for short link outages to minutes, or even hours for longer link outages. If the buffering is minutes or hours, a complete test may be run, and then the data can be extracted from the buffer. In this case, the microcontrollers act like data loggers, logging the data until the test is complete, at which time it can be communicated to an external computer.
Video
[0057] In another aspect of the invention, video may be taken of the top of the washer either through a transparent lid, or with the lid removed and any safety mechanisms deactivated. This video may be synchronized with any electronic data by including, in the view of the video camera, a display showing a running timer that may be correlated to the instrumentation data signals.
[0058] The video may be very useful for tracking the target cloth during periods when it is not in contact with the contact sensors, but is visible from the top of the washer. Combining the target cloth position data from the video with target cloth position from the instrumentation data can give a much more detailed representation of the trajectory of the target cloth and the cloth motion in general. The information from the Hall effect sensors, the radial contact sensor data, the circumferential contact sensor data and information from the video, such as the initial location and movement of the impeller and the location of the target cloth when it is on the top of the washer, can be combined to give a three dimensional picture in time of the location of the impeller, target cloth and wash basket.
[0059] While the present invention has been described with reference to the above described embodiments, those of skill in the art will recognize that changes may be made thereto without departing from the scope of the invention as set forth in the appended claims. | A method and apparatus for measuring and recording conditions inside a chamber containing cloth items and fluid is provided. The method involves placement of contact sensors inside a wash chamber that can detect contact with a target cloth. The method also involves placement of rotation sensors for determining the position of rotating components within the washer. The method also involves installation of friction sensors that can measure forces between cloth items and the surfaces of the wash chamber. The method also involves installation of a fluid flow sensing system to determine the direction of fluid flow in the washer. All or some of the aforementioned signals are communicated from instruments within the washer to an external computer and may be converted to spatial locations for the impeller, target cloth and basket. Video may be recorded and combined with the sensor data to develop a more complete picture of cloth motion. | 3 |
RELATED APPLICATIONS
[0001] This application in part discloses and claims subject matter disclosed in my earlier filed patent application Ser. No. 12/386,825, filed on Apr. 23, 2009. This application also discloses and claims subject matter disclosed in my earlier filed patent application Ser. No. 12/380,928, filed on Mar. 4, 2009. These applications are incorporated by reference herein. Applicant claims priority under 35 USC §120 therefrom.
FIELD OF THE INVENTION
[0002] The present invention relates to tongue and groove floor, ceiling and wall panels sculpted out of a single piece of wood or other material, with a veneer atop each panel.
BACKGROUND OF THE INVENTION
[0003] Floor panels, such as parquet floor panels, are typically made of an array of interlocking tongue and groove panels. However, often the grooves are gouged out of a single piece of wood, and the corresponding tongues are sculpted out of a single piece of wood, making their manufacture time consuming and subject to minute, small errors.
[0004] U.S. Pat. No. 2,257,048 of Fulbright describes a panel with multiple layers glued together.
[0005] The flooring of Martensson in his U.S. Pat. No. 6,101,778, uses a solid base layer with bonded profiled edges providing snap-together profiles. U.S. Pat. No. 2,283,135 of Bruce for flooring uses solid strips of wood with no veneer upper layer. The flooring of Martensson in his U.S. Pat. No. 6,101,778, uses a solid base layer with bonded profiled edges providing snap-together profiles. However, Martensson '778 requires coupling the respective tongue 7 and groove 6 to respective separate panels 1 , each respective panel 1 having respective lower portions 15 which mate with corresponding flanges 16 and 14 extending respectively from tongue 7 and groove 6 .
[0006] U.S. Pat. No. 2,283,135 of Bruce for flooring uses solid strips of wood with no veneer upper layer. Bruce 135 also uses nails 10 to attach elongated strips 1 to subflooring, a feature not required by Applicant's interlocking panels.
[0007] Martensson '778 therefore uses the idea of one side clamping to the other side, Martensson '778 also uses long panels, not interlocking square panels like the Applicant herein. Martensson '778 does not describe a system where oppositely located, coordinated rotating bits can sculpt not only the tongue and grooves of wall panels from solid blocks, and Martensson cannot sculpt panel edges by rounding or texturing them. Martensson does not describe using coordinated pairs of rotating bits that changes the surface topography of wall panels to the designer's liking and preferences. Martensson '778 does not describe a method of simultaneously cutting opposing sides of a floor panel at the same time, which would make the panels more uniform in structure.
OBJECTS OF THE INVENTION
[0008] It is therefore an object of the present invention to provide tongue and groove floor, ceiling and wall panels using multiple bonded sheet construction, with minimal or no gouging or sculpting of pieces of wood.
[0009] It is also an object to provide a panel made up of three sheets of substantially the same equal thickness, and to form respective protruding tongues and receptacle grooves from overlapping of the substantially equal thick sheets forming the panel.
[0010] It is also an object of the present invention to provide a relatively tight fit of the tongue portions into the respective groove portions of the assembled sheets forming each panel.
[0011] It is also an object of the present invention to be able to install multiple floor, ceiling or wall board panels in a single plane parallel to the surface upon which the panels are being installed.
[0012] Other objects which become apparent from the following description of the present invention.
SUMMARY OF THE INVENTION
[0013] In keeping with these objects and others which may become apparent, the floor, ceiling and wall panels of this invention are constructed of multiple board sheets, preferably three board sheets, of material bonded together using adhesive. The preferred material for each of the board sheets is plywood which may be of different or the same thickness for each. Other rigid durable sheet materials may be used such as flake board or composites incorporating wood materials. Materials such as foamed PVC can also be used for one or all three of the layers. The three pieces of plywood can be attached not only by adhesive, such as glue, but also by fasteners, such as nails, staples, etc. joining one or more of the three layers. The three pieces of plywood also can have plastic sheets inserted between the panels to reduce moisture between them. Also, the three layers can use different types of plywood. Optionally, each plywood board sheet layer can be treated differently to be water resistant, fire proof or insect resistant, etc. A typical fire resistant wood sealer such as described in U.S. Pat. No. 5,879,593 is mixed with the glue before the glue is applied between the layers. Optionally, waterproof glues, such as Gorilla® glue or Titebond® waterproof glue may be used. Fireproof glue, such as GB18583-2001/BS5852 manufactured by Stenzhen Gokangali Chemical Laboratory, Ltd. may be used and mixed with the glue. Insect resistant adhesives, such as manufactured by Henkel Adhesives can also be mixed with the glue and applied between the board layers.
[0014] In one embodiment for floor boards, all three board sheets are of identical size and shape (although the thickness may be different as desired). The shape, as described in the drawings, is either square or rectangular. (Other tiling shapes, such as hexagons or octagons, with straight sides may also be used.) By offsetting the middle board sheet layer so that two adjacent sides extend beyond the top and bottom board sheet layers which are in registration, a protruding tongue is developed on two adjacent sides while the opposite sides will have grooves. Thus such panels can be used to cover a large floor, ceiling or wall area using normal tongue-in-groove techniques by fitting the protruding tongues into the grooves of adjacent panels; a small amount of adhesive may be used in these fitted edges, but it is not essential in all applications. No routing of the edges is required to form the tongues or grooves.
[0015] In an alternate embodiment for walls and ceilings, the middle board sheet is smaller in size than the top and bottom board sheets which are in registration. The middle board sheet is centered within the top and bottom board sheets thus forming grooves on all four edges. To assemble these panels to cover a larger area, separate connecting slat tongues are used to connect the panels thereby acting as the tongues for a tongue-in-groove fit. By using a combination of short slat tongues and long slat tongues, large interconnected areas can be covered. By using slat tongues wider than the depth of two adjacent panel grooves, visible linear grooves the depth of the thickness of the top board sheet are formed between panels. They can be used to simulate a grout line in ceramic tile installations.
[0016] The top surface of each panel can be finished in a variety, of ways including grooving to simulate a parquet floor or patterns formed of veneers with oriented grain directions. It is also known that the pattern can be enhanced by one or more veneer pieces applied to the top of the assembled panels. Any appropriate sealant and/or stain can be used. Obviously the finish for a floor application would probably be different from that of a wall panel due to wear characteristics. Large inlay designs can be accommodated on several adjacent panels which are then assembled like a jigsaw puzzle to form a coherent design.
[0017] The tongue and the reciprocating groove are formed by attaching three panel board sheets, preferably plywood, together in a “sandwiched” overlying pattern. Because the plywood board sheets are flat, the tongues and corresponding grooves extend uni-directionally therefrom. They can be assembled by moving the tongue portions in one surface plane, such as horizontally for a floor or ceiling, and vertically for a wall. They do not need to be inserted at an angle and then locked in place by being moved in a non-planar fashion.
[0018] It is further noted that in the case the underlying wall to which the panels are being installed is warped and non-planar, an underlying layer of Sheetrock® wall board can be installed between the panels and underlying warped surface, to provide a relatively flat surface for installation of the array of panels.
[0019] In an alternate embodiment, the square or rectangular floor, wall, or ceiling panels are of different construction using a different fabrication method. The three-layer plus veneer construction of the embodiment above is replaced by a single solid layer with a veneer layer on top. The single layer is preferably a wood product such as plywood, high density fiberboard (HDF), or medium density fiberboard (MDF). The fabrication method involves the use of edge routing using a tongue cutter on one edge and a groove cutter on the opposite edge to form the edge shapes equivalent to those of the previous embodiment. If two routing heads are spaced apart the appropriate distance for a particular sized panel, a single pass can form a tongue on one edge and a groove on the opposite edge simultaneously. One cutter is spun clockwise while the second is spun counterclockwise to equalize the forces on the panel. Thus two passes are needed to form the edges of a panel. If the panel is square, the spacing of the two router heads need not be changed to form the edges orthogonal to the first ones formed. The veneer layer, which may be bamboo, birch, or other woods such as cherry wood, is adhesively bonded to the top surface as in the earlier embodiment.
[0020] It is further noted that the wood material can be as described in my co-pending patent application Ser. No. 12/380,928 filed Mar. 4, 2009. In that application, I describe a wood article of manufacture thus produced which can be a laminate panel of particle board of particular particle size and particle to glue ratios which provides a durable, lightweight and strong panel which gives the appearance of wood because its exterior veneer layer or layers are made from a thin wood veneer of approximately 0.35 to 0.70 millimeters in thickness. A preferable veneer thickness is 0.5 mm, although veneer thicknesses may range from 0.3 to 0.5 mm, although other suitable thicknesses may be used.
[0021] My co-pending application Ser. No. 12/380,928 describes that to keep the wood lightweight, the particles should be more than 1.0 mm and less than 5.0 mm in length, depth and width, preferably about 3.0 mm in length, depth and width so that they are small enough to have sufficient density for strength, but large enough to provide air spaces therebetween, to be filled by resin glue at a weight lighter than natural wood. The ratio of wood particles to glue should be preferably 100:10 to 100:12, i.e. 100 kg of raw wood particle material to mix with 10-12 kg of glue. The maximum permitted is 100:28, i.e. 100 kg wood particle to 28 gms glue. With the aforementioned parameters, the finished particle board density is 0.8 g/cm 3 . To keep the panels smooth and flat, sanding should be applied to keep height deviation within 0.1 mm. Also, to have sufficient glue without undue buildup or air bubbles, glue should be applied in the ratio of 320 g/m 2 . To further keep the panels smooth, the thin veneer layers with glue are heat and pressure treated at 110 C and pressure of about 1 cm 2 per 7-8 kg. On the edges, veneer strips of about 1.5 cm in with and 0.5 to about 1 mm in thickness, with lengths of 1 meter or more, are applied at a pressure of approximately 200 pounds with a glue at approximately 200 degrees C. heat. For fireproofing, insect proofing or water proofing, a thin layer of Wood Fire Resisting Liquid is applied by putting the panels in a tank full of liquid of pressure more than 1, 2 Mp 3 P for at least 8 hours immersion, which will soak about 150 kg/cubic meter of product into the wood. At low ambient pressure, the wood must be soaked for at least 48 hours, as long as 80 to 100 kg/cubic meter is absorbed into the wood over the 48 hour period. Exterior brushing can also be applied in three layer coatings to a thickness of 0.5 kg/cubic meter. Although other fire resistant, water resistant and pest or mold resistant sealers can be applied, a typical fire resistant liquid wood sealer is described, for example, in U.S. Pat. No. 5,879,593, including a liquid composition of potassium hydroxide, sodium carbonate, silica and water.
[0022] My co-pending application Ser. No. 12/380,928 also describes a manufacturing system, method, and article of manufacture which is capable of producing a laminated product that has the appearance of traditional birch plywood. The laminated article of manufacture has an interior similar to that of particle board, but the laminated article of manufacture should has increased strength and lighter weight compared to that of other particle boards. Additionally, the laminated article of manufacture is capable of having at least one or a plurality of thin or ultra-thin veneers placed on opposing surfaces and opposing edges, and is capable of being painted. The laminated article of manufacture is capable of being manufactured from recycled biodegradable products. In the U.S. and Europe, the natural color of a natural wood surface having a clear coat with the texture of the wood showing through is highly desirable, especially that of Birch Wood grown in Northern Asia, (Northern China and Russia). Birch wood also has characteristics of surface hardness, beautiful texture, a minimum amount of scar marks, black lines, or mineral lines, does not easily break or change shape after having been cut in the format of veneer sheet (usually in the size of 4 feet by 8 feet, 0.3 mm to 0.5 mm in thickness), but these high quality veneers are becoming less and less available, because a 3 foot or larger diameter birch tree takes more than 60 years to grow, and there are only 3 to 5 sheets of 4 feet by 8 feet veneers in that tree. These 3 to 5 sheets of veneers, may be used on surfaces of 4 feet by 8 feet plywood, and used for the manufacture of 5 storage units for toys. One class room of furniture, however, needs at least 5 times of this amount of veneer, which means that a classroom's furniture needs five birch trees to manufacture the furniture.
[0023] My co-pending application Ser. No. 12/380,928 further describes a system which may be used instead of using birch veneer. Chinese Cottonwood (called Chinese Birch or Chinese beech) which grows on tree farms and takes approximately 7-10 years to grow, and which grows into a one and half foot diameter tree may be used. Veneers from these trees, however, have soft surfaces that may scratch easily. However, such veneers may be hardened by methods of the present invention, resulting in finished products that look substantially the same as Russian Birch, or other highly desired woods.
[0024] My co-pending application Ser. No. 12/380,928 also describes that by using the above wood materials and paint processes of the present invention, wood products can be made completely of recycled wood and veneers from fast growing Chinese trees, thus, minimizing impact to the environment.
[0025] My co-pending application Ser. No. 12/380,928 further describes a core of fresh or green wood and/or recycled wood products, which are processed down to a particle size of less than 5 mm, and preferably less than 3 mm, and bonded together with glue, opposing surface inner veneer bonded to opposing surfaces of the core with glue, opposing surface outer veneer bonded to opposing surface inner veneer with glue, opposing edge veneer bonded to opposing edges of the core with glue. Each of the veneers is preferably 0.5 mm thick, although suitable veneer thicknesses may range from 0.3 to 0.5 mm. The article of manufacture thus produced is a laminated wood product having a particle to glue ratios that provides a durable, lightweight, strong attractive product that gives the appearance of wood.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The present invention can best be understood in connection with the accompanying drawings. It is noted that the invention is not limited to the precise embodiments shown in drawings, in which:
[0027] FIG. 1 is a perspective exploded view of three board sheets forming a square panel with integral tongues on two edges and grooves on the other two.
[0028] FIG. 2 is a top view of the assembled panel of FIG. 1 .
[0029] FIG. 3 is a top view of an alternate embodiment square panel with grooves on all four edges.
[0030] FIGS. 4A to 4F show a typical installation of the floor board panels, wherein:
[0031] FIG. 4A is a top plan view of a floor panel;
[0032] FIG. 4B is a front elevation view thereof;
[0033] FIG. 4 BB is a close up partial detail view of the floor panel in FIG. 4B , taken along view circle line “ 4 BB” of FIG. 4B ;
[0034] FIG. 4C is a right side elevation view thereof;
[0035] FIG. 4D is a close detail view taken along view circle line 5 D of FIG. 5C ;
[0036] FIG. 4E is a top plan view during installation of an array of multiple panels; and
[0037] FIG. 4F is a top plan view after completion of installation of the array of multiple panels.
[0038] FIGS. 5A to 5R show the installation of a typical wall board, wherein:
[0039] FIG. 5A is a top plan view of a wall panel 10 of square configuration as in FIG. 3 ;
[0040] FIG. 5B is a front elevation view thereof;
[0041] FIG. 5C is a right side elevation view thereof;
[0042] FIG. 5D is a close up detail view taken along view circle line “ 5 D” of FIG. 5C ;
[0043] FIG. 5E is top plan view of a connecting slat for the panel of FIG. 16A ;
[0044] FIG. 5F is front view thereof.
[0045] FIG. 5G is side view thereof;
[0046] FIG. 5 GG is a close-up detail view of the connecting slat shown in FIG. 5G , taken along view circle line “GG” of FIG. 5G ;
[0047] FIG. 5H is a top plan view of a rectangular wall panel;
[0048] FIG. 5I is a right side elevation view thereof;
[0049] FIG. 5J is a front elevation view thereof;
[0050] FIG. 5K is top plan view of a connecting slat for the panel of FIG. 16H ;
[0051] FIG. 5L is front view thereof;
[0052] FIG. 5M is a top plan view of an array of wall panels during installation;
[0053] FIG. 5N is a top plan view of the array of wall panels also showing connecting slats;
[0054] FIG. 5O is a top plan view of a completed array of wall panels;
[0055] FIG. 5P is a top plan view of the array of connecting slat tongues for the wall panels;
[0056] FIG. 5Q is inverted cross sectional view viewed through view line “ 5 Q- 5 Q” of FIG. 50 ;
[0057] FIG. 5R is a close-up detail view of taken along viewing circle line “ 5 R” of FIG. 5Q ;
[0058] FIGS. 6A-6R show the installation of a typical ceiling pattern, wherein:
[0059] FIG. 6A is a top plan view of a ceiling panel 100 of square configuration, similar to wall panel 10 as in FIG. 3 ;
[0060] FIG. 6B is a front elevation view thereof;
[0061] FIG. 6C is a right side elevation view thereof;
[0062] FIG. 6D is a close up detail view taken along view circle line “ 6 D” of FIG. 6C ;
[0063] FIG. 6E is top plan view of a short connecting slat for the panel of FIG. 6A ;
[0064] FIG. 6F is front view thereof.
[0065] FIG. 6G is side view thereof;
[0066] FIG. 6H is a close up partial detail thereof, taken along view line circle “ 6 H” of FIG. 6G ;
[0067] FIG. 6I is a top plan view of a long rectangular slat for the ceiling panel;
[0068] FIG. 6J is a front view thereof;
[0069] FIG. 6K is a right side elevation view thereof;
[0070] FIG. “ 6 L” is a close up detail thereof, taken along view line circle “ 6 L” of FIG. 6K ;
[0071] FIG. 6M is a top plan view of an array of ceiling panels and connecting slats during installation;
[0072] FIG. 6N is a top plan view of the array of ceiling panels further during installation;
[0073] FIG. 6O is a top plan view of the array of connecting slat tongues for the ceiling panels;
[0074] FIG. 6P is a top plan view of a section of panels installed on a ceiling;
[0075] FIG. 6Q is an inverted cross sectional view viewed through view line “ 6 Q- 6 Q” of FIG. 6P ;
[0076] FIG. 6R is a close-up detail view taken along view circle line “ 6 R” of FIG. 6Q ;
[0077] FIG. 7 is a top view of an alternate embodiment showing a square panel fabricated using a different method, wherein the base section is a single solid layer with a veneer layer bonded on top;
[0078] FIG. 8 is an edge view of the panel of FIG. 7 ;
[0079] FIG. 9 illustrates the fabrication method using two counter-rotating routing heads;
[0080] FIG. 9A is an enlarged close-up detail view of a modified bit with a textured cutting edge;
[0081] FIG. 9B is an enlarged close-up detail view of a modified panel tongue with surface texturization imparted by a bit with a textured cutting edge; and,
[0082] FIG. 9C is an enlarged close-up detail view of a of a modified panel groove with surface texturization imparted by a modified bit with a textured cutting edge.
DETAILED DESCRIPTION OF THE INVENTION
[0083] FIG. 1 shows three equal-sized board sheet layers, top 2 , middle 3 , and bottom 4 which will be adhesively bonded at the factory to form square panel 1 of the first embodiment with an offset middle layer. Each of the layers is preferably a board sheet of plywood. They can all be the same thickness, such as 6 mm, or the board sheets can be of different thickness as desired. These panels, of convenient size such as 12″ or 16″ can be used as floor tiles or for wall covering. While dimensions may vary, preferably square panels 1 have upper board sheets 2 and lower board sheets 4 which are 32 cm in length, sandwiching a mid board sheet 3 of 32 cm in length, which extends outward displaying a protruding tongue of 1.3 cm and a corresponding recess on an opposite side of 1.3 cm in depth. Each board sheet is preferably 6 mm, making panel 1 of three board sheets 2 , 3 and 4 about 18 mm in thickness.
[0084] Each board sheet is preferably a rectangular cuboid, also called a rectangular parallelepiped, of which all faces are rectangular and where “rectangular” implies both rectangles and squares.
[0085] Each of the panels may be of one piece construction, plywood, or other suitable construction. A preferred embodiment of a floor panel system, as in FIG. 1 and FIGS. 4A-4F , constructed in accordance with the present invention comprises:
[0000] A floor panel system, comprising:
a plurality of substantially same size and shape wood floor panels 1 matingly and releasably adjoined one to the other, each floor panel 1 of the plurality of substantially same size and shape wood floor panels 1 adapted to matingly and releasably adjoin to at least two other floor panels 1 of the plurality of substantially same size and shape wood floor panels 1 ,
the each floor panel 1 having:
opposing substantially rectangular cuboid shaped one piece wood board sheets 2 and 4 ,
each opposing substantially rectangular cuboid shaped one piece wood board sheets 2 and 4 of the opposing substantially rectangular cuboid shaped one piece wood board sheets 2 and 4 comprising: substantially flat opposing first and second surfaces, opposing first edges substantially perpendicular to the substantially flat opposing first and second surfaces, opposing second edges substantially perpendicular to the substantially flat opposing first and second surfaces and substantially perpendicular to the substantially opposing first edges,
a substantially centrally disposed substantially rectangular cuboid shaped one piece wood board sheet 3 having substantially the same size and shape as the each opposing substantially rectangular cuboid shaped one piece wood board sheet and having substantially flat opposing third surfaces, opposing third edges, and opposing fourth edges,
the substantially flat opposing third surfaces bonded to each the substantially flat opposing second surface of the each opposing substantially rectangular cuboid shaped one piece wood board sheet and configured to have one of the opposing third edges and one of the opposing fourth edges extending from the each floor panel 1 forming substantially perpendicular adjacent tongues and substantially perpendicular adjacent grooves.
[0096] FIG. 2 shows a top view showing how the offset center board sheet 3 simultaneously forms two adjacent tongue edges as well as two opposite groove edges 5 .
[0097] FIG. 3 is a top view of square panel 10 with smaller central board sheet 13 , top board sheet 11 , bottom board sheet 14 and grooves 12 on all four edges. External tongue slats are used with this embodiment.
[0098] Each of the panels may be of one piece construction, plywood, or other suitable construction. Each board sheet is preferably a rectangular cuboid, also called a rectangular parallelepiped, of which all faces are rectangular and where “rectangular” implies both rectangles and squares.
[0099] A preferred embodiment of a wall panel system, as in FIGS. 5A-5R constructed in accordance with the present invention, or a ceiling panel system, as in FIGS. 6A-6R , comprises:
[0000] a wall or ceiling panel system, comprising:
a plurality of substantially same size and shape wood wall or ceiling panels 10 or 100 panels 100 matingly and releasably adjoined one to the other, each wall or ceiling panel 10 or 100 of the plurality of substantially same size and shape wood wall or ceiling panels 10 or 100 adapted to matingly and releasably adjoin to at least two other wall or ceiling panels 10 or 100 of the plurality of substantially same size and shape wood wall panels 10 or ceiling panels 100 ,
the each wall panel 10 or ceiling panel 100 having:
opposing substantially rectangular cuboid shaped one piece wood board sheets 11 and 14 ,
each opposing substantially rectangular cuboid shaped one piece wood board sheet 11 and 14 of the opposing substantially rectangular cuboid shaped one piece wood board sheets 11 and 14 comprising: substantially flat opposing first and second surfaces, opposing first edges substantially perpendicular to the substantially flat opposing first and second surfaces, opposing second edges substantially perpendicular to the substantially flat opposing first and second surfaces and substantially perpendicular to the substantially opposing first edges,
a substantially centrally disposed substantially rectangular cuboid shaped one piece wood board sheet 13 smaller than and having substantially the same shape as the each opposing substantially rectangular cuboid shaped one piece wood board sheets 11 and 14 and having substantially flat opposing third surfaces, opposing third edges, and opposing fourth edges,
the substantially flat opposing third surfaces bonded to each the substantially flat opposing second surface of the each opposing substantially rectangular cuboid shaped one piece wood board sheet and sandwiched therebetween and configured to have the opposing third edges and the opposing fourth edges inwardly disposed within the each wall panel 10 forming opposing first grooves 12 and opposing second grooves 12 substantially perpendicular to the opposing first grooves, each the opposing first groove 12 of the opposing first grooves 12 and each the opposing second groove 12 of the opposing second grooves 12 having substantially the same depth;
a plurality of spacer block standoffs 27 adapted to be fastened to a wall or ceiling; a plurality of first connecting slat tongues fastened to the plurality of standoffs 27 ,
each first connecting slat tongue of the plurality of first connecting slat tongues adapted to be matingly and removably received within two adjacent abutting opposing first grooves of the opposing first grooves of two adjacent abutting the plurality of substantially same size and shape wood wall panels 10 or ceiling panels 100 ;
a plurality of second connecting slat tongues 28 ,
each second connecting slat tongue 28 of the plurality of second connecting slat tongues 28 adapted to be matingly and removably received within two adjacent substantially collinear second grooves 12 of the opposing second grooves 12 of the two adjacent abutting the plurality of substantially same size and shape wood wall panels 10 or ceiling panels 100 and substantially perpendicular to the plurality of first connecting slat tongues 26 .
[0115] FIGS. 4A-4F show a typical installation of the array of floor board panels 1 with equal sized floor board panels 1 made of top panel board sheet 2 , staggered mid panel board sheet 3 leaving two adjacent tongue portions and lower panel board sheet 4 , wherein the staggered tongues engage grooves 5 forward between opposite edges of top panel board sheet 2 and lower panel board sheet 4 of an adjacent wall panel 10 . While dimensions may vary, preferably square panels 1 have upper board sheets 2 and lower board sheets 4 which are 32 cm in length, sandwiching a mid sheet 3 of 32 cm in length, which extends outward displaying a protruding tongue of 1.3 cm and a corresponding recess on an opposite side of 1.3 cm in depth. Each board sheet is preferably 6 mm, making panel 1 of three board sheets 2 , 3 and 4 about 18 mm in thickness. Floor board panels 1 are installed in a plane in the direction of the arrows indicated.
[0116] FIGS. 5A-5R show the installation of a typical wall board, where the panels are joined by short slat tongues 26 or long slat tongues 28 of FIG. 11 , which are fastened by fasteners such as nails or screws through slats 26 or 28 and through standoff spacer blocks 27 to an underlying wall surface.
[0117] Each top and bottom board sheets 11 and 14 of square panel 10 of FIGS. 3 and 5A , is preferably 39 cm square, sandwiching smaller mid board sheet 13 of 37 cm in length therebetween. Connecting slat tongues 26 are preferably 37 cm in length and 3.6 cm in width and 0.7 cm in thickness, to fit in the grooves 12 on all sides of panel 10 , wherein grooves 12 are 0.7 cm in width, to engage corresponding tongues of 0.7 cm in length.
[0118] Each top and bottom board sheets of rectangular panels 10 a of FIG. 5H are also 39 cm in width, but 120.2 cm in length. Smaller mid board sheets are 3.6 cm in width and 199.4 cm in length, engaging corresponding grooves of 199.4 cm in length formed within rectangular panels 10 a.
[0119] As shown in FIG. 50 , when assembled in the vertical planar direction of the arrows, two square panels plus corresponding slat tongues each have a length of 40.6 cm×40.6 cm, combined with a long rectangle and corresponding slat tongue totaling 121.8 cm in length, for a combined assembly of 203 cm. Other panels may be added depending upon the wall size to be covered.
[0120] In an alternate embodiment, the wall panels can be installed on a ceiling, but preferably each square panel is 2 feet by 2 feet (60.96 cm×60.96 cm).
[0121] FIG. 6A is a top view of square ceiling panel 100 with smaller central board sheet 113 , top board sheet 111 , bottom board sheet 114 and grooves 112 on all four edges. External short connecting slat tongues 126 and long connecting slat tongue 128 of FIG. 6E through 6L are used with this embodiment to connect ceiling panels 100 to each other. Slat tongues 126 or 128 are inserted in place in a plane, in the direction of the arrows shown in FIG. 6M and FIG. 6N . The ceiling panels 100 are connected to a ceiling in a manner similar to that of wall panels in FIG. 5A through FIG. 5R , with fasteners, such as nails or screws, through slat tongues 126 or 128 and bracing standoff spacer blocks 127 . While dimensions may vary, ceiling panels 100 are preferably 60.8 cm square (approximately two feet square). Mid panel board sheet 113 is about 56.8 cm square, revealing grooves on all four sides of about 2 cm in depth. Top board sheet 11 is about 0.4 cm in thickness, mid board sheet 113 is about 0.6 cm (as is groove 112 formed thereat) and bottom board sheet is about 0.5 cm in thickness. Short slat tongues 126 are about 5.8 cm×6.54 cm, and long slat tongues 128 are about 120.14 cm in length×6.54 corn in width. FIG. 6Q shows a section of a ceiling covered by a number of square ceiling panels 100 . Ceiling board panels 1 are installed in a plane in the horizontal planar direction of the arrows indicated. The ceiling panels 100 can be also installed suspended in a drop ceiling configuration, where there are perpendicular connectors or frames spaced between the panels 100 and the ceiling surface above the panels.
[0122] In an alternate embodiment for floor panel 1 , as previously shown in FIGS. 1 , 2 , and 4 A- 4 F, while the three board sheets are substantially equal in thickness, in this alternate embodiment mid board sheets 3 forming tongues may be alternatively slightly thicker at the tongue end than at the end forming the groove between respective top and bottom board sheets 2 and 4 , so that they form a tight fit when pushed into the respective grooves formed between top board sheet 2 and bottom board sheet. For example, the protruding end can be 0.63 cm but the groove can be 0.6 cm. Floor board panels 1 are installed in a plane in the direction of the arrows indicated, without any need to divert away from the horizontal planar direction of installation.
[0123] FIGS. 7-9 pertain to an alternate embodiment of panel of this invention which can be used for the same purposes as in FIGS. 4A-4F , 5 A- 5 R, and 6 A- 6 R. Although the panel is shown as a square panel, the fabrication method can also be extended to cover any rectangular panel as well.
[0124] FIG. 7 shows panel 200 with top veneer layer 202 which is adhesively bonded and protruding tongue edges 204 . FIG. 8 is a side edge elevation of panel 200 showing solid base layer 210 and tongue 204 on one side with matching groove 206 on the opposite edge. Note that panel 200 has the same geometric edge features and veneer placement as the panel described if FIGS. 1-3 . Base layer 210 is typically plywood, HDF, or MDF.
[0125] FIG. 9 illustrates the fabrication method whereby two opposite edges are formed simultaneously. Panel 200 is fed between two counter-rotating routing cutters, 215 and 217 cutting the tongue and groove respectively on opposite edges. The spacing of cutters 215 and 217 matches the desired panel dimensions.
[0126] Each panel can vary in size, but is preferably 30 cm by 30 cm in length and width. The solid supporting layer is preferably 2 cm in height and the top veneer is preferably 0.6 cm in height, although it can be varied up to preferably 0.8 or 1.0 cm in height. Preferably the total panel height is between about 2.6 cm to 3.0 cm in height. The tongue portion protrudes out about 1.5 cm in two directions and the respective grooves are each about 1.5 cm in depth.
[0127] FIGS. 9A , 9 B and 9 C show an alternate embodiment for a method of imparting extrications, such as serrations, threaded cuts and other textures surfaces, which can be used to provide a stronger gripping surface between the tongue of a panel with the groove of an adjacent panel.
[0128] For example, FIG. 9A shows a modified bit 315 with a textured cutting edge 316 .
[0129] FIG. 9B shows a modified panel 300 with a tongue 304 having surface texturization 305 imparted by a bit 315 with a textured cutting edge 316 .
[0130] FIG. 9C shows a modified panel 300 ′ with a groove 306 having surface texturization 307 imparted by a modified bit with a textured cutting edge.
[0131] In the foregoing description, certain terms and visual depictions are used to illustrate the preferred embodiment. However, no unnecessary limitations are to be construed by the terms used or illustrations depicted, beyond what is shown in the prior art, since the terms and illustrations are exemplary only, and are not meant to limit the scope of the present invention.
[0132] It is further known that other modifications may be made to the present invention, without departing the scope of the invention, as noted in the appended Claims. | A method of making a set of interlocking floor or wall panels includes providing a single solid layer with a veneer layer on top. The fabrication method involves the use of edge routing using a tongue cutter on one edge and a groove cutter on the opposite edge to form the edge shapes equivalent to those of the previous embodiment. If two routing heads are spaced apart the appropriate distance for a particular sized panel, a single pass can form a tongue on one edge and a groove on the opposite edge simultaneously. One cutter is spun clockwise while the second is spun counterclockwise to equalize the forces on the panel. Thus two passes are needed to form the edges of a panel. The veneer layer, which may be bamboo, birch, or other woods such as cherry wood, is adhesively bonded to the top surface. | 4 |
THis is a divisional of copending application Ser. No. 07/433,361, filed Nov. 7, 1989, now U.S. Pat. No. 5,026,464.
FIELD OF THE INVENTlON
The present inVention relates to a method and an compounds which are organic compounds, such as chlorofluorocarbons (CFCs) and trichloroethylene, containing fluorine, chlorine, or bromine.
BACKGROUND OF THE INVENTION
Halogenated organic compounds, which are organic compounds, such as CFCs and trichloroethylene, containing fluorine, chlorine, or bromine, find wide use as solvents refrigerants, and fire extinguishing agents, and are employed in large quantities. Therefore, they are of importance in the industry. However, these compounds are volatile, and many of the halogenated organic compounds used in the industry are emitted to the environment such as the atmosphere, water, or soil. It has been pointed out that such emissions destroy the stratospheric ozone layer and generate carcinogenic substances, thus seriously affecting the environment.
Where used, halogenated organic compounds should be disposed of, no appropriate method of decomposing them is currently available because their reactivity is extremely low.
The decomposition techniques which have been heretofore reported are mainly combustion techniques at hazardous organic wastes using such techniques is described in an article entitled "Laboratory Investigation of Thermal Degradation of a Mixture of Hazardous Organic Compounds" by John L. Graham, Douglas L. Hall, and Barry Dellinger, in Environ. Sci. Technol., Vol. 20, No. 7, 1986, pp. 703-710. In this method, however, the energy efficiency is extremely low, because halogenated organic compounds are burned together with a large amount of fuel, such as hydrocarbon. Further, the whole apparatus cannot be made in small size, since the fuel tank and the incinerator are large. In addition, free halogens produced by combustion come into contact with the wall of the incinerator that is at high temperatures to thereby attack the incinerator. This phenomenon is especially conspicuous where organic fluorine compounds are burned.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method of efficiently decomposing halogenated organic compounds, such as chlorofluorocarbons (CFCs) and trichloroethylene, by plasma reaction.
It is another object of the invention to provide a method and an apparatus for efficiently decomposing halogenated organic compounds by efficiently supplying the compounds in a liquid phase into a plasma.
If is a further object of the invention to provide an apparatus capable of decomposing halogenated organic compounds without producing hazardous by-products.
The present inventors and others have investigated a method capable of easily decomposing halogenated organic compounds and have found a method of decomposition using a plasma produced either by induction heating making use of radio-frequency waves or microwaves or by DC heating. The present invention utilizes the fact that substances are very reactive in the plasma state. Even chemicals resistant to decomposition such as halogenated organic compounds can be decomposed in a short time. In particular, within a plasma with a temperature as high as 10,000° C., almost all molecules are considered to dissociate into atoms.
In accordance with the present invention, halogenated organic compounds are introduced into a plasma to decompose them. In one embodiment of the invention, a halogenated organic compound is introduced into a plasma, together with a substance for reacting with the decomposed halogenated organic compound, such as water. The decomposed compound is caused to react with water to prevent the decomposed compound from returning to its original state.
A preferred method according to this invention comprises bubbling a carrier gas through the halogenated
is contained in the carrier gas, bubbling the carrier gas through a liquid substance for reacting with he decomposed halogenated organic compound so that the liquid substance may be contained in the carrier gas, and mixing the carrier gas containing the halogenated organic compound with the carrier gas containing the liquid substance. The mixture is then introduced into a plasma.
In accordance with this invention, there is also provided an apparatus for decomposing halogenated organic compounds. The apparatus comprises a chamber, for example, a cylindrical tube, and a gas supply nozzle opening into the tube. An RF coil is wound around the tube so that when excited it will heat the contents of the tube to the plasma state. A first container is provided for containing the halogenated organic compound in liquid phase. A carrier gas inlet tube is arranged to introduce a carrier gas source into the first container. A second container is provided to contain water. A carrier cas inlet tube is arranged to introduce carrier gas source into the second container. A gas mixer mixes the gas from the first container with the gas from the second container and forces the resulting mixture into the gas supply nozzle.
According to a preferred embodiment of the apparatus for decomposing halogenated organic compounds, a liquid intake tube is mounted in the gas supply nozzle into which a liquid to be supplied to the plasma formed in the chamber.
According to yet another preferred embodiment of the apparatus, means are provided for ejecting a gas or liquid into a portion of the plasma to extinguish the portion of the plasma.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a system for decomposing a halogenated organic compound, the system being fabricated in accordance with the invention;
FIGS. 2 and 3 are schematic diagrams of other systems according to the invention for decomposing a halogenated organic compound; and
FIG. 4 is a schematic diagram of a further system according to the invention for preventing generation of hazardous by-products.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, there is shown a system according to the invention. This system has a torch 1 for producing a plasma by induction. The torch 1 comprises a cylindrical tube 2 made from an insulating material such as quartz, a gas supply nozzle 3, and an RF coil 4 wound around the tube 2. The nozzle 3 is provided with an annular groove 5. An annular plate 6 is welded to the outside of the groove 5. The plate 6 is provided with a number of minute holes 7. The groove 5 is connected with one end of a hole 8 formed in the nozzle 3. The other end of the hole 8 is connected with a tube 9 at the top of the nozzle 3.
The tube 9 branches into a first tubing extending into a first container 10 and a second tubing extending into a second container 11. The first container 10 holds a halogenated organic compound 12, such as CFC, to be decomposed and is in liquid phase. One end of a carrier gas supply tube 13 is inserted in the halogenated organic compound contained in the first container 10. The other end of the supply tube 13 is connected with an argon gas source 15 via a flow controller 14. The second container 11 contains water 16 in which one end of another
is connected with the argon gas source 15 via a flow controller 18.
A selector valve 19 is mounted in the tube 9 to force either gas coming from the first container 10 and the second container 11 or gas coming from the argon gas source 20 into the hole 8 formed in the nozzle 3. The flow of gas from the argon gas source 20 is controlled by the flow controller 21.
The cylindrical tube 2 forming the plasma torch 1 has an opening 22 near its lower end. An exhaust tube 23 that it connected with a cyclone 24 is connected with the opening 22. The cyclone 24 acts to trap powdered material contained in the exhaust fumes. The exhaust fumes passed through the cyclone 24 is guided into a tube 25 which extends into a container 27. An alkaline water solution 26 such as potassium hydroxide (KOH) is contained in the container 27. A tube 28 for discharging internal gas extends from the top of the container 27. The discharge tube 28 is connected with another container 30 near its bottom. The container 30 holds an alkaline solid 29, such as calcium oxide (CaO). The gas passed through the interstices among the particles of the solid 29 is allowed to escape through a discharge tube 31 extending from the top of the container 30.
The operation of the system constructed as described above is now described. In the initial state, the selector valve 19 mounted in the tube 9 is so operated that argon gas from the argon gas source 20 is supplied into the groove 5 via the hole 8 formed in the nozzle 3. The gas then passes through the numerous minute holes 7 formed in the plate 6, and are injected into the cylindrical tube 2. Under this condition, RF waves are supplied to the RF coil 4 to produce a plasma P by an igniting mechanism (not shown).
Subsequently, the selector valve 19 is switched to the other state so that the gases from the first container 10 and the second container 11 may be supplied into the groove 5 via the hole 8 in the nozzle 3, instead of the argon gas from the argon gas source 20. In the first container 10, the carrier gas supply tube 13 connected with the argon gas source 15 is immersed in the halogenated organic compound solution 12 contained in the container. The argon gas is ejected from the end of the tube 13 which opens into the compound solution 12, at a flow rate controlled by the flow controller 14. Since the argon gas is bubbled through the organic compound solution 12, the vaporized organic compound is contained in the gaseous argon and discharged into the tube 9 from the first container 10. In the second container 11, the carrier gas supply tube 17 connected with the argon gas source 15 is inserted in the water 16 contained in the container. The argon gas is ejected from the end of the tube 17 that opens into the water 16, at a suitable flow rate controlled by the flow controller 18. Because the argon gas is bubbled through the water, the vaporized water is contained in the gaseous argon and discharged into the tube 9 from the second container 11.
The argon gas containing the vapor of halogenated organic compound is mixed with the argon gas containing the water vapor, at the branching point J of the tube 9. The mixture gas is forced into the groove 5 via the hole 8 in the nozzle 3. The mixture gas then passes through the numerous minute holes 7 formed in the plate 6 and is ejected into the tube 2. Finally, the mixture gas is admitted into the plasma P. At this time, the temperature of the plasma is between 10,000° C. and 15,000° C. The halogenated organic compound introduced into the plasma P are decomposed at a high efficiency because of the high temperature and caused to react.
Where trichlorofluoromethane (Freon 11) CCl 3 F is decomposed as a halogenated organic compound within the plasma, the compound reacts with water as given by
CCl.sub.3 F+2H.sub.2 O=CO.sub.2 +3HCl+HF (1)
The exhaust fumes containing the decomposed molecules are sent to the cyclone 24 through the exhaust tube 23 from the opening 22 of the tube 2 that is located close to the bottom of the tube 2. At this time, if the water is insufficient in quantity as compared with the Freon 11, excessive carbon will be produced. Fine powder of carbon and other substances contained in the exhaust fumes are trapped in the cyclone 24. The gas passed through the cyclone 24 is introduced into the water solution of a potassium hydroxide 26 in the container 27 through the tube 25. As a result, the exhaust fumes containing acids such as HCl and HF are neutralized. The neutralized gas is admitted into the container 30 from the bottom of the container 26 via the exhaust tube 28 and then dehydrated by the calcium oxide 29 in the container 30. The dehydrated gas is a stable compound which hardly affects the environment. This gas is appropriately emitted into the atmosphere.
Since the high-temperature plasma P is produced close to the nozzle 3, this nozzle is heated by the plasma. Because the temperature of the plasma P is quite high, there arises the possibility that the nozzle melts or deforms. Therefore, it is necessary to form a coolant passage in the nozzle 3 and to circulate a coolant such as water or oil through the passage, for cooling the nozzle. If the temperature of the coolant is so low that the nozzle is cooled excessively, then the vaporized halogenated organic compound and water forced into the groove 5 through the hole 8 return into droplets. For this reason, it is desired to preheat the coolant to about 40° C. to 50° C., for preventing the nozzle from getting cooled excessively.
Table 1 shows the results of an experiment conducted to decompose trichlorofluoromethane (Freon 11) CCl 3 F that is a halogenated organic compound, by the aforementioned system. In this experiment, the above-described system was used, and a gas chromatograph (not shown) was connected with the discharge tube 31. Qualitative and quantitative analyses were made of the gas decomposed by the plasma. The used induction plasma generator was operated under the following conditions:
______________________________________flow rate of argon gas 40 l/minRF power supplyplate voltage 6 KVplate current 2.2Areaction pressure 1 atm.______________________________________
TABLE 1______________________________________concentration of added gas Freon 11gas of halogenated gas decompositionorganic compound kind concentration ratio______________________________________2.2% over 99%2.2% H.sub.2 2.5% 62%2.2% H.sub.2 O 2.5% over 99%______________________________________
As can be seen from Table 1, when only a CFC was introduced into the plasma, the decomposition ratio of the Freon 11 exceeded 99%. However, a large amount of carbon adhered to the inner wall of the tube 2. When hydrogen gas was introduced into the plasma together with Freon 11, the decomposition reaction did not proceed after a decomposition ratio of 62% was reached. Also, deposition of carbon was not suppressed. On the other hand, when a mixture of Freon 11 and water was admitted into the plasma, the decomposition rate exceeded 99%. Further, generation of carbon was greatly suppressed. When a metal compound, such as calcium oxide (not shown in Table 1) was added instead of hydrogen gas or water, a metal halide such as calcium chloride or calcium fluoride was obtained. Such metal halides are stable compounds and hardly affect the environment.
Table 2 shows the results of an experiment performed to decompose 1,1,2-trichloro-1,2,2-trifluoroethane (Freon 113) CCl 2 FCClF 2 . This experiment shows that when only Freon 113 was decomposed at a rate exceeding 99%, in the same way as Freon 11. When water was added to Freon 113, the decomposition rate exceeded 99%. Also, generation of carbon was greatly suppressed. The used induction plasma generator was operated in the same conditions as in the aforementioned experiment on decomposition of Freon 11.
TABLE 2______________________________________concentration of added gas Freon 113gas of halogenated gas decompositionorganic compound kind concentration ratio______________________________________0.57% over 99%0.57% H.sub.2 2.5% 99%0.57% H.sub.2 O 2.6% over 99%______________________________________
Referring to FIG. 2, there is shown another system according to the invention. It is to be noted that like components are denoted by like reference numerals throughout all the figures. In this example, a torch 1 has a nozzle 3 provided with a hole 8 connected with a groove 5. The nozzle 3 is centrally provided with a hole 50. A tube 9 through which carrier gas flows from a first container 10 and a second container 11 is connected with the central hole 50. In the first container 10, argon has is bubbled through a halogenated organic compound. In the second container 11, argon gas is bubbled through water. A tube 52 is connected with the hole 8 and also with an argon gas source 20 via a flow controller 51.
In this example, when the system is in its initial condition, the selector valve 19 mounted in the tube 9 is operatede to supply argon gas from the argon gas source 20 into the hole 50 in the nozzle 3. The argon gas from the argon gas source 20 is supplied into the groove 5 via the hole 8, at a flow rate controlled by the flow controller 51. Therefore, inside the tube 2, argon gas is ejected at two locations, i.e., from minute holes 7 in the plate 6 and from the hole 50. Under this condition, RF waves are supplied to an RF coil 4, and a plasma P is ignited by an igniting mechanism.
Thereafter, the selector valve 19 is switched to the other state. Instead of the argon gas from the argon gas source 20, the gases from the first container 10 and the second container 11 are ejected into the tube 2 via the hole 50 in the nozzle 3. As a result, the halogenated organic compound admitted into plasma P is decomposed at a high efficiency because of high temperature, in the same way as in the example described already in connection with FIG. 1.
Referring to FIG. 3, there is shown a further system according to the invention. A torch 1 has a nozzle 3 provided with a hole 8 connected with a groove 5. A tube 61 is connected with the hole 8 and also with an argon gas source 63 via a flow controller 62. A tube 64 is inserted into the central portion of the nozzle 3. A tube 65 is mounted inside the tube 64. Therefore, the central portion of the nozzle 3 is of double structure. The outer tube 64 is connected with a mixer 66. A halogenated organic compound 68 held in a container 67 is supplied into the mixer 66 by a pump 69. Also, water 71 received in a container 70 is supplied into the mixer 66 by a pump 72. The tube 65 is connected with an argon gas source 74 via a flow controller 73.
In the initial state of the system constructed as described above, argon gas is supplied at an adequate flow rate from the argon gas source 63 via the flow controller 62, forced through the tube 61, the hole 8, the groove 5, and the minute holes 7, and ejected into the tube 2. Under this condition, RF waves are fed to an RF coil 4 to ignite a plasma P by an igniting mechanism (not shown). Then, the pumps 69 and 72 are operated to supply both halogenated organic compound and water into the mixer 66, where they are mixed together. The mixture liquid passes through the tube 64 into the outer tube of the double tubes mounted in the center of the nozzle 3.
Argon gas is supplied from the argon gas source 74 into the inner tube 65 of the double tubes in the center of the nozzle 3 at a flow rate controlled by the flow controller 73. At the front end of the double tubes, argon gas is ejected from the inner tube. This atomizes the mixture of the halogenated organic compound and water supplied from the outer tube of the double tubes. The atomized mixture is introduced into the plasma together with argon gas.
The decomposition of Freon 11 proceeds within substances are maintained at high temperatures for a long time, the decomposition reaction proceeds further, producing hazardous substances such as dioxin. FIG. 4 shows an example of the invention which is designed, taking the above consideration into account In this example, an annular passage 80 is formed in the tube 2. A multiplicity of minute holes 81 are formed in the inner wall of the passage 80. A tube 84 which is connected with an argon gas source 88 via a flow controller 82 is connected with the passage 80. The flow rate of the gas from the argon gas source 88 is appropriately controlled by the flow controller 82, and the gas is supplied into the passage 80. Then, the argon gas is ejected into the tube 2 from numerous minute holes 11.
In the system described just above, the argon gas from the minute holes 81 in the passage 80 is injected into the plasma P. Consequently, the plasma is momentarily cooled. The portion of the plasma into which gas stream is admitted disappears. Hence, the decomposed halogenated organic compound is prevented from being placed in the plasma for a long time. Thus, no excessive reactions proceed. In this way, production of hazardous by-products is prevented.
In the above examples, argon gas is ejected into plasma. If generation of NO x produces no problems, nitrogen gas may be ejected. Also, water may be ejected instead of gas. In this case, HCl and HF produced by decomposition are absorbed into water. This absorption is promoted by ejecting an alkaline water solution into plasma flame and neutralizing the acids. An alkaline gas such as ammonia may be used to neutralize the acids. In this case, the acid gases can be converted into solids such as ammonium chloride and ammonium fluoride by neutralization. Also in the above examples, argon gas is ejected from the minute holes 11 to extinguish plasma. Alternatively, an annular slit is formed, and gas or liquid is injected into a plasma from this slit.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details can be made therein without departing from the spirit and scope of the invention. In the example shown in FIG. 1, the nozzle of the torch is provided with a single groove. Argon gas and carrier gas containing a vaporized halogenated organic compound are interchangeably supplied into the groove. The carrier gas is caused to contain the vapor of the organic compound by bubbling gas through the organic compound. The nozzle may also be provided with two grooves one of which is supplied with argon gas and carrier gas interchangeably. The carrier gas is made to contain a vaporized halogenated organic compound by bubbling gas through the organic compound. The other groove is constantly supplied with argon gas. Also in the above examples, halogenated organic compounds are decomposed by an RF induction plasma generator. This plasma generator for decomposing the compounds may be of direct heating type. In the above description, halogenated organic compounds in liquid phase are introduced into plasma. The invention is also applicable to the case in which halogenated organic compounds in gaseous or liquid phase are decomposed.
Having thus described our invention with the detail and particularity required by the Patent Laws, what is claimed and desired to be protected by Letters Patent is set forth in the following claims. | A halogenated organic compound is introduced into a plasma. In the plasma state, substances are very reactive and chemical substances which are not readily decomposed such as halogenated organic compounds are decomposed in a short time. Specifically, in a high-temperature plasma exceeding 10,000° C., almost all molecules are considered to dissociate into atoms. A reactive substance such as water is introduced into a plasma together with a halogenated organic compound. The decomposed halogenated organic compound is caused to react with the reactive substance, for preventing the decomposed organic compound from returning to its original state. | 8 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of application serial no. 07/295,873 filed Jan. 11, 1989.
FIELD OF THE INVENTION
The present invention concerns blends of cyanate ester compounds and brominated polystyrene.
BACKGROUND OF THE INVENTION
Cyanate ester resins are generally considered to be high performance thermosetting resins at least to the extent that they usually exhibit high glass transition temperatures. In some applications such as in electrical laminates and the like it is desirable that they exhibit high fire retardant properties in that it is desirable that they exhibit an Underwriters Laboratory test no. 94 rating of V-0. The current industry standard cyanate ester resin is based on bisphenol A.
A typical method for obtaining ignition resistance in cyanate ester systems has been by the addition of brominated epoxy resins as disclosed by R. Kubens et al. in U.S. Pat. No. 3,562,214. Unfortunately, the addition of epoxy resins can result in a lower glass transition temperature, a decreased onset of thermal degradation, and a loss in moisture resistance with a corresponding increase in dielectric constant for the blended system.
Blends of non-brominated cyanate esters with brominated cyanate esters are disclosed by C. Burkhards et al. in U.S. Pat. No. 4,097,455, by G. W. Bogan and G. A. Monnerat in U.S. Pat. No. 4,806,625 and by J. P. Godschalx et al. in U.S. Pat. No. 4,782,178: however, this method to achieve flame resistance can be expensive. Blends of cyanate ester resins with ethylenically unsaturated reactive brominated monomers are disclosed by G. W. Bogan and P. A. Lucus in U.S. Pat. No. 4,746,727: however, some of these monomers, like bromostyrene, may suffer from volatility problems. Moreover, these approaches may still experience similar losses of performance as enumerated above with the brominated epoxy blends, or they may suffer from a lack of availability.
It would be desirable to have available, a cyanate ester resin composition which (1) has excellent flame resistance without an unacceptable sacrifice in the physical, thermal, electrical and moisture resistance properties which renders these cyanate ester resins desirable in such applications, (2) at the same time be reasonably affordable in terms of cost, and (3) maintains handling characteristics of an unmodified cyanate ester resin.
SUMMARY OF THE INVENTION
The present invention pertains to a blend comprising (A) at least one compound containing a plurality of --OCN groups: and (B) a brominated homopolymer or brominated interpolymer of styrene or alkyl- or halo-substituted styrene or any combination thereof: wherein components (A) and (B) are present in an amount such that the blend contains a bromine content of from about 4 to about 25 percent by weight based on the combined weight of components (A) and (B).
Another aspect of the present invention pertains to a curable composition comprising the aforementioned blend and a curing amount of a suitable curing agent therefor.
Another aspect of the present invention pertains to an article resulting from curing the aforementioned curable composition.
The present invention provides a cyanate ester resin composition which has excellent flame resistance without an unacceptable sacrifice in the physical, thermal, electrical and moisture resistance properties which renders these cyanate ester resins desirable in electrical laminate and encapsulation applications and at the same time be reasonably affordable in terms of cost. In some instances, one or more of the properties are actually improved.
DETAILED DESCRIPTION OF THE INVENTION
Suitable brominated polymers which can be employed herein include, for example the brominated homopolymers and brominated interpolymers of styrene, halo-or alkyl-substituted styrene, said alkyl groups having from 1 to about 10 carbon atoms. Particularly suitable brominated polymers include, for example, brominated homopolymers or brominated interpolymers of styrene, o-methylstyrene, p-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene p-tert-butylstyrene, p-chlorostyrene, α-methylstyrene, combinations thereof and the like. Also suitable are the bromine-containing polymers resulting from polymerizing bromine-containing monomers such as, for example, bromostyrene, dibromostyrene, tribromostyrene, C 1 -C 4 alkyl substituted monobromostyrene, C 1 -C 4 alkyl substituted dibromostyrene, any combination thereof and the like as well as their interpolymers with any one or more non-bromo-containing polymerizable ethylenically unsaturated monomer as enumerated above.
The brominated polymers which can be employed herein include, for example, those which contain suitably from about 24 to about 70, more suitably from about 50 to about 68, most suitably from about 55 to about 68, percent bromine by weight: have a weight average molecular weight (Mw) suitably from about 750 to about 700,000, more suitably from about 2,000 to about 600,000, most suitably from about 2,000 to about 500,000: and a degree of polymerization (Dp) suitably from about 3 to about 3,000, more suitably from about 10 to about 2,500, most suitably from about 10 to about 2,300.
Suitable cyanate ester compounds employed in the present invention as the compound containing a plurality of --OCN groups are the cyanate esters of a hydrocarbon-aromatic hydroxyl containing compound which can be prepared by reacting a hydrocarbon-aromatic hydroxyl containing compound resin with cyanogen chloride or cyanogen bromide.
The hydrocarbon-aromatic hydroxyl containing compound resin can be prepared by reacting an unsaturated hydrocarbon or mixture of such hydrocarbons with an aromatic hydroxyl containing compound. Suitable methods as well as suitable aromatic hydroxyl containing compounds and unsaturated hydrocarbons are described by Vegter et al. in U.S. Pat. No. 3,536,734, Nelson in U.S. Pat. No. 4,390,680, Gebhart et al. in U.S. Pat. No. 3,557,239 and Nelson in U.S. Pat. No. 4,167,542, all of which are incorporated herein in their entirety.
Particularly suitable unsaturated hydrocarbons which, either in crude or purified state, can be employed include, for example, butadiene, isoprene, piperylene, cyclopentadiene, cyclopentene, 2-methylbutene-2, cyclohexene. cyclohexadiene, methyl cyclopentadiene, dicyclopentadiene, limonene, dipentene, linear and cyclic dimers of piperylene, methyl dicyclopentadiene, dimethyl dicyclopentadiene, norbornene, norbornadiene, ethylidine norbornene, mixtures thereof and the like. Also suitable unsaturated hydrocarbons include the other dimers, codimers, oligomers and cooligomers of the aforementioned unsaturated hydrocarbons. Particularly suitable unsaturated hydrocarbons which can be employed herein include, for example, a dicyclopentadiene concentrate containing from about 70 to about 100 percent by weight of dicyclopentadiene: from zero to about 30 percent by weight of C 9 -C 2 - dimers or codimers of C 4 -C 6 dienes such as, for example, cyclopentadieneisoprene, cyclopentadiene-piperylene, cyclopentadienemethylcyclopentadiene, and/or dimers of isoprene, piperylene, methyl cyclopentadiene and the like: from about zero to about 7 percent by weight of C 14 -C 18 trimers of C 4 -C 6 dienes and from about zero to about 10 percent by weight of aliphatic diolefins such as, for example, piperylene, isoprene, 1,5-hexadiene and cyclic olefins such as cyclopentadiene, methyl cyclopentadiene, cyclopentene and the like. Methods of preparations for these dicyclopentadiene concentrates and more detailed descriptions thereof can be found collectively in the aforementioned U.S. Pat. No. 3,557,239 issued to Gebhart et al and U.S. Pat. No. 4,167,542 issued to Nelson.
Also, particularly suitable unsaturated hydrocarbons which can be employed include a crude dicyclopentadiene stream containing from about 10 to about 70 percent by weight dicyclopentadiene, from about 1 to about 10 percent codimers and dimers of C 4 -C 6 hydrocarbons (described above), from about zero to about 10 percent oligomers of C 4 -C 6 dienes and the balance to provide 100 percent, C 4 -C 6 alkanes, alkenes and dienes.
Also, particularly suitable unsaturated hydrocarbons which can be employed include a crude piperylene or isoprene stream containing from about 30 to about 70 percent by weight piperylene or isoprene, about zero to about ten percent by weight C 9 -C 12 and codimers of C 4 -C 6 dienes, and the balance to provide 100 L30 percent by weight of C 4 -C 6 alkanes, alkenes and dienes.
Also particularly suitable unsaturated hydrocarbons which can be employed include a composition comprising from about 95 percent to about 100 percent by weight of dicyclopentadiene and the balance, if any, to provide 100 percent by weight of C 4 -C 7 saturated or unsaturated hydrocarbons or oligomers thereof.
Also, particularly suitable are hydrocarbon oligomers prepared by polymerization of the reactive components in the above hydrocarbon streams e.g., dicyclopentadiene concentrate, crude dicyclopentadiene, crude piperylene or isoprene, individually or in combination with one another or in combination with high purity diene streams.
Suitable aromatic hydroxyl-containing compounds which can be employed herein include those described in the aforementioned patents by Vegter et al., Gebhart et al. and Nelson. Suitable such aromatic hydroxylcontaining compounds include, for example, those compounds which contain one or two aromatic rings, at least one phenolic hydroxyl group and at least one ortho or para ring position with respect to a hydroxyl group available for alkylation. These and others are disclosed in the aforementioned patents by Vegter et al., Gebhart et al. and Nelson which have been incorporated herein by reference.
Particularly suitable aromatic hydroxylcontaining compounds which can be employed herein include, for example, phenol, chlorophenol, bromophenol, dimethylphenol, o-cresol, m-cresol, p-cresol, hydroquinone, catechol, resorcinol, guaiacol, pyrogallol, phloroglucinol, isopropylphenol, ethylphenol, propyiphenol, t-butyl-phenol, isobutylphenol, octylphenol, nonylphenol, cumylphenol, p-phenylphenol, o-phenylphenol, m-phenylphenol, Bisphenol A, dihydroxydiphenyl sulfone, mixtures thereof and the like.
The process of reacting the unsaturated hydrocarbon with the aromatic hydroxyl-containing compound can best be conducted in two steps.
In the first step, the unsaturated hydrocarbon is fed slowly into a mixture of the aromatic hydroxylcontaining compound and a suitable catalyst at temperatures suitably from about 40° C. to about 130° C., more suitably from about 50° C. to about 100° C., most suitably from about 60° C. to about 90° C. for a period of time sufficient to complete the addition of the unsaturated hydrocarbon while maintaining the exothermic reaction temperature within the above stated limits, suitably from about 0.25 to about 8, more suitably from about 0.5 to about 6, most suitably from about 1 to about 4 hours.
Suitable Lewis acid catalysts which can be employed herein include, for example, those described in the aforementioned U.S. Pat. No. 3,536,734 to Vegter et al. and U.S. Pat. No. 4,390,680 to Nelson. Particularly suitable catalysts include, for example, BF 3 , AlCl 3 , FeCl 3 , SnCl 4 , the coordination complexes thereof, and combinations thereof and the like.
The Lewis acid catalyst is employed in a catalytically effective amount, i.e. that amount which will sufficiently catalyze the reaction between the unsaturated hydrocarbon and the aromatic hydroxylcontaining compound at the particular reaction conditions employed. Usually, these amounts include that which provides a molar ratio of catalyst to aromatic hydroxyl-containing compound suitably from about 0.002:1 to about 0.1:1. more suitably from about 0.003:1 to about 0.05:1, most suitably from about 0.003:1 to about 0.01:1.
In the second step, the reaction mixture of the first step is allowed to digest at temperatures suitably from about 90° C. to about 180° C., more suitably from about 140° C. to about 150° C. for a period of time sufficient to substantially complete the reaction between the unsaturated hydrocarbon(s) and aromatic hydroxylcontaining compound(s), suitably from about 1 to about 8. more suitably from about 2 to about 6, most suitably from about 3 to about 4 hours.
The unsaturated hydrocarbon and the aromatic hydroxyl-containing compound are reacted in amounts which provide a molar ratio of aromatic hydroxylcontaining compound to unsaturated hydrocarbon suitably from about 1:1 to about 20:1, more suitably from about 2:1 to about 15:1, most suitably from about 3:1 to about 10:1. When the molar ratio is above about 20:1, reactor capacity is reduced by excess reactants and therefore effective yields are reduced. No particular advantage is seen for conducting the reaction at higher ratios. When the molar ratio is below about 1:1, incomplete reaction of the unsaturated hydrocarbon will likely occur, thus preventing complete conversion of the reactants to the desired product.
The resinous product can be recovered, if desired, from the reaction mixture by simply removing the excess aromatic hydroxyl-containing compound by distillation or the like. In the preparation of cyanate resins, the reaction mass can be reacted directly. without purification, with cyanogen, chloride or cyanogen bromide to produce a polycyanate resin.
The cyanate ester of the above resin prepared from one or more unsaturated hydrocarbons and one or more aromatic hydroxyl-containing compounds hereinafter referred to as unsaturated hydrocarbon/aromatic hydroxyl-containing resin can be prepared by the procedure described by D. J. Murray and E. P. Woo in U.S. Pat. No. 4,748,270 which is incorporated herein by reference in its entirety. The cyanate ester of the above unsaturated hydrocarbon/aromatic hydroxyl containing resin can also be prepared by the procedure described by Ernst Grigat and Rolf Putter in U.S. Pat. No. 3,553,244 which is incorporated herein by reference in its entirety.
The preferred compounds containing a plurality of --OCN groups are those represented by the following formula I ##STR1## wherein each R and R' is independently hydrogen or a hydrocarbyl or hydrocarbyloxy group having suitably from 1 to about 12, more suitably from 1 to about 6, most suitably from 1 to about 4, carbon atoms or a halogen atom, preferably chlorine or bromine: each m independently has a value suitably from 1 to about 6, more suitably from 1 to about 3, most suitably from 1 to about 2, and m' has a value suitably from zero to about 4, more suitably from zero to about 2, most suitably from zero to about 0.4.
Other suitable compounds containing a plurality of --OCN groups include those represented by the following formulas II, III and IV ##STR2## wherein each A is independently a divalent hydrocarbyl group containing suitably from 1 to about 12, more suitably from 1 to about 6, most suitably from 1 to about 4 carbon atoms, --S--, --S--S--, --SO--, --SO 2 --, --O--, or --CO--; each A' is independently a divalent hydrocarbyl group containing suitably from 1 to about 12, more suitably from 1 to about 6, most suitably from 1 to about 4 carbon atoms: each Q is independently a hydroxyl or --OCN group with the proviso that at least two of them are --OCN groups: R is hydrogen or an alkyl group having from 1 to about 4 carbon atoms: each X is independently hydrogen or a hydrocarbyl group containing suitably from 1 to about 12, more suitably from 1 to about 6, most suitably from 1 to about 4 carbon atoms or a halogen atom, preferably chlorine or bromine: n has a value of zero or 1; n' has an average value suitably from zero to about 5, more suitably from zero to about 3, most suitably from zero to about 2; and n" has an average value suitably from about 0.001 to about 4, more, suitably from about 0.001 to about 2, most suitably from about 0.001 to about 1.
The term hydrocarbyl as employed herein means any aliphatic, cycloaliphatic, aromatic, aryl substituted aliphatic or cycloaliphatic, or aliphatic or cycloaliphatic substituted aromatic groups. The aliphatic groups can be saturated or unsaturated. Likewise, the term hydrocarbyloxy means a hydrocarbyl group having an oxygen linkage between it and the carbon atom to which it is attached.
Particularly suitable other cyanate ester compounds include, for example, bisphenol A dicyanate, bisphenol K dicyanate, bisphenol F dicyanate, methylene bis (3,5-dimethylphenyl-4-cyanate), 4,4'-thiodiphenylcyanate, polycyanate of phenol-formaldehyde novolac resins, polycyanate of cresol-formaldehyde novolac resins, combinations thereof and the like.
The cyanate ester containing compound and the brominated styrene polymers or resins are blended in amounts which provide the resultant blend with a bromine content suitably from about 4 to about 25, more suitably from about 8 to about 20, most suitably from about 10 to about 18, percent bromine by weight based upon the combined weight of the cyanate containing compound and the brominated styrene polymer or resin.
Suitable curing agents for the compositions of the present invention include, for example, acids, bases, nitrogen or phosphorus compounds, transition metal salts or complexes, combinations thereof and the like, such as metal salts of aliphatic and aromatic carboxylic acids, tertiary amines, and the like. Particularly suitable curing agents include, for example, cobalt octoate, cobalt naphthenate, cobalt acetylacetonate, zinc octoate, zinc naphthenate, tin octoate, diazobicyclo-(2,2,2)-octane, triethylamine, combinations thereof and the like.
If desired, the compositions can be blended with other compounds such as, for example, solvents, fillers, mold release agents, pigments, dyes, flow modifiers, combinations thereof and the like.
Suitable such solvents include, for example, halogenated hydrocarbons, aromatic hydrocarbons, cyclic ethers, amides, ketones, combinations thereof and the like. Particularly suitable solvents include, for example, dimethylformamide, tetrahydrofuran, methylethylketone, methylene chloride, combinations thereof and the like.
Suitable such fillers include, for example, graphite, carbon, metals, glass, natural and synthetic materials, combinations thereof and the like in the form of matts, monofiliments, multifilaments, woven fibers, powders, rovings, and the like. Particularly suitable fillers include, glass fibers, graphite or carbon fibers, combinations thereof and the like.
The blends of the present invention can be employed in the preparation of coatings, laminates, composites, eastings, moldings and the like.
In the preparation of laminates, the blends are mixed with a curing agent and applied to a substrate material. Then two or more plies of the impregnated substrate are subjected to heat and pressure resulting in a laminate or composite. Electrical laminates are prepared in the same manner as the laminates or composites except that they contain at least one outer layer of an electrical conducting material.
Suitable substrate materials for preparing the laminates and composites include, for example, glass, nylon, rayon, polyamide, graphite, and the like. The substrate materials can be in the form of woven fabric, mat, monofilament, multifilament rovings, and the like.
Suitable electrical conducting materials for use in the electrical laminates include, for example, gold, silver, copper, aluminum, and the like.
The following examples are illustrative of the invention, but are not to be construed as to limiting its scope in any manner.
The following components are employed in the examples and comparative experiments.
Component A is a cyanate containing resin prepared by cyanating with cyanogen chloride the reaction product of dicyclopentadiene containing three percent or less of codimers and unreactive lights and phenol, said reaction product having an average phenolic hydroxyl functionality of about 2.25 and a phenolic equivalent weight of 163 to 168. The cyanate equivalent weight is 191 (calculated).
Component B is a brominated polystyrene resin having a bromine content of about 60-62 percent by weight, a weight average molecular weight (Mw) of about 470,000 and a Dp of 1,700-2,200.
Component C is bromostyrene monomer.
Component D is the reaction product of vinyl benzyl chloride and tetrabromobisphenol A . The resultant vinylbenzyl ether product has a bromine content of 41.2 percent by weight.
Component E is a brominated vinyl ester resin (60% non-volatiles in styrene) containing 33.3 percent bromine by weight based o non-volatiles only.
Component F is a polycarbonate resin prepared by reacting phosgene with tetrabromobisphenol A. The resultant brominated polycarbonate has a Mw of 100,000 to 200,000 and a bromine content of 56 percent by weight.
Component G is a brominated polystyrene resin having a bromine content of about 68 percent by weigh and a Mw of about 2000. The resin is available from the Ferro Corp. as Pyro-Chek LM.
Component H is the dicyanate ester of bisphenol A available from the Mitsubishi Gas Co. under the name BT-2000.
Component I is a brominated polystyrene resin having a bromine content of about 60.3 percent by weight and a weight average molecular weight (Mw) of about 450,000-480,000.
Component J is a brominated polystyrene resin having a bromine content of about 60 percent and a molecular weight (Mw) of about 215,000. The resin is available from the Ferro Corp. as Pyro-Chek 60PB.
Component K is a diglycidyl ether of tetrabromobisphenol A with a bromine content of 18-20 percent and an epoxide equivalent weight of 405-425.
Component L is a brominated polystyrene resin having a bromine content of about 60 percent and a molecular weight (Mw) of about 10,000 prepared by the
EXAMPLE 1
Blending of Resins
19.7 grams of brominated polystyrene (Component B) are dissolved in 50 ml of tetrahydrofuran. To this mixture are added 80.3 grams of a cyanate ester resin (Component A). The mixture is placed on aluminum foil in a vacuum oven to remove the solvent. During the first hour, the temperature is 128° C. or less. The vacuum is approximately 25 inches (635 mm) Hg. After the first hour, the temperature varies between 128° C. and 137° C. The vacuum is increased to 28 to 29 inches Hg. After a total of 22/3 hours, the resin blend is removed from the oven and allowed to cool. The resulting product contains approximately 12% bromine by weight.
Casting and Curing of Resin Blend
Seventy grams of the above material are heated in a 130° C. oven. To this is added 1.75 grams of a catalyst solution. The solution has been made by dissolving 0.32 gram of cobalt (III) acetylacetonate in 5 grams of divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into a glass mold, the internal surfaces of which are treated with Release All #30. The mold is placed in an oven preheated to 177° C. After one hour, the temperature is raised to 225° C., followed by 21/2 hours at 250° C. This casting is tested for flammability by the UL 94 test.
EXAMPLE 2
Blending of Resins
13.1 grams of brominated polystyrene (Component B) are dissolved in 50 ml of tetrahydrofuran. To this mixture is added 86.9 grams of a cyanate ester resin (Component A). The mixture is placed on aluminum foil in a vacuum oven to remove the solvent. During the first hour, the temperature is 128° C. or less. The vacuum is approximately 25 inches Hg. After the first hour, the temperature varies between 128° C. and 137° C. The vacuum is increased to 28 to 29 inches (711-736 mm) Hg. After a total of 22/3 hours, the resin blend is removed from the oven and allowed to cool. The resulting product contains approximately 8% bromine.
Casting and Curing of Resin Blend
70 grams of the above material are heated in a 130° C. oven. To this heated mixture is added 1.75 grams of a catalyst solution. The solution has been made by dissolving 0.32 gram of cobalt (III) acetylacetonate in 5 grams of divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into a glass mold, the internal surfaces of which are treated with Release All #30. The mold is placed in an oven preheated to 177° C. After one hour, the temperature is raised to 225° C., followed by 2 1/2 hours at 250° C. This casting is tested for flammability by the UL 94 test.
EXAMPLE 3
Blending of Resins
52.5 grams of brominated polystyrene (Component B) are dissolved in 75 ml tetrahydrofuran (THF) This is blended into 347.5 gm of cyanate ester resin (Component A) preheated to 90° C. The blend is placed into a vacuum oven at 115° C. to 125° C. for 1.75 hours under a maximum vacuum of 29 to 30 in. (736-762 mm) Hg.
Casting and Curing of Resin Blend
4.54 gm of catalyst solution is added to the blend. The solution has been made by dissolving 1.5 gm cobalt (III) acetylacetonate in 28.5 gm of divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into an aluminum mold, the internal surfaces of which are treated with a 5% by wt. solution of Dow Corning 20 silicone oil in isopropanol as a mold release agent. The mold is placed in an oven preheated to 175° C. for one hour. Then the temperature is raised to 225° C. for one hour, followed by 2 hours at 50° C. The physical and electrical properties of the cured product are given in Table I.
EXAMPLE 4
Blending of Resins
20.45 grams of brominated polystyrene (Component G) are dissolved in 100 ml of methylene chloride. To this mixture are added 55.0 grams of a cyanate ester resin (Component A). After the cyanate ester is dissolved in the solvent, the solvent is removed using a rotary evaporator. The maximum temperature reached is 165° C. and the maximum vacuum obtained is 10 mm Hg. The solvent removal requires about 32 minutes. The resulting product contains approximately 18 percent bromine by weight.
Casting and Curing of Resin Blend
65.9 grams of the above material are heated in a 150° C. oven until the material becomes pourable. To this is added 1.65 grams of a catalyst solution. The solution is made by dissolving 0.771 gram of cobalt (III) acetylacetonate in 12 grams of divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into a preheated (177° C.) glass mold, the internal surfaces of which are treated with Release All #30 as a mold release agent. The mold is placed in an oven preheated to 177° C. After seventy minutes, the temperature is raised between 220° C. to 225° C. for an hour, followed by two hours at 248° C. to 250° C. The thermal, electrical and moisture resistance properties are given in Table I.
EXAMPLE 5
Blending of Resins
44.78 grams of brominated polystyrene (Component I) and 105.22 grams of cyanate ester resin (Component H) are mixed in 300 ml of methylene chloride. The solvent is removed using a rotary evaporator. The maximum temperature reach is 170° C. and the maximum vacuum obtained is 10 mm Hg. The solvent removal requires about 38 minutes. The resulting product contains approximately 18 percent bromine by weight.
Casting and Curing of Resin Blend
139.3 grams of the above material are heated in a 177° C. oven until the material becomes pourable. To this is added 3.48 grams of a catalyst solution. The solution is made by dissolving 0.835 gram of cobalt (III) acetylacetonate in 13 grams of divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into a preheated (177° C.) aluminum mold, the internal surfaces of which are treated with a five percent by weight solution of Dow Corning DC-20 silicone oil in isopropanol as a mold release agent. The mold is placed in an oven preheated to 177° C. for one hour, followed by four hours at 225° C. After several days the casting is postcured for two hours at 250° C. The electrical, thermal, and moisture resistance properties are give in Table I.
EXAMPLE 6
Blending of Resins
15.0 grams of brominated polystyrene (Component L) are dissolved in 100 ml of methylene chloride. To this mixture are added 60.0 grams of a cyanate ester resin (Component A). After the cyanate ester is dissolved in the solvent, the solvent is removed using a rotary evaporator. The maximum temperature reached is 139° C. and the maximum vacuum obtained is 9 mm Hg. The solvent removal requires about 48 minutes. The resulting product contains approximately 12% bromine by weight.
Casting and Curing of Resin Blend
68.3 grams of the above material are heated in a 150° C. oven until the material becomes pourable. To this is added 1.48 grams of a catalyst solution. The solution is made by dissolving 2.25 grams of cobalt (III) acetylacetonate in 35 grams of divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into a preheated (175° C.) glass mold, the internal surfaces of which have been treated with Release All #30 as a mold release agent. The mold is placed in an oven preheated to 177° C. After 1, hours, the temperature is raised to 250° C. for two hours. The thermal, electrical and moisture resistance properties are given in Table I.
COMPARATIVE EXPERIMENT A
600 grams of a cyanate ester resin (Component A) are heated in a 120° C. oven. To this is added 6.8 grams of a 10% catalyst mixture of cobalt (III) acetylacetonate in divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into an aluminum mold, the internal surfaces of which are treated with a 5% by wt. solution of Dow Corning 20 silicone oil in isopropanol as a mold release agent. The mold is placed in an oven preheated to 100° C. After one hour, the temperature is increased to 175° C. for one hour, and then the temperature is raised to 225° C. for one hour, followed by 2 hours at 250° C. The physical and electrical properties of the cured product are given in Table I.
COMPARATIVE EXPERIMENT B
Blending of Resins
73.3 grams of bromostyrene monomer (Component C) are weighed into 326.7 grams of a cyanate ester resin (Component A), preheated to 100° C. The resulting product contains approximately 8% bromine.
Casting and Curing of Resin Blend
To this heated mixture is added 4.54 grams of a catalyst solution. The catalyst solution is made by dissolving 1.5 grams of cobalt (III) acetylacetonate in 28.5 grams of divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into an aluminum mold, the internal surfaces of which are treated with a 5% by wt. solution of Dow Corning 20 silicone oil in isopropanol as a mold release agent. The mold is placed in an oven preheated to 125° C. After one hour, the temperature is raised to 175° C. for one hour, followed by one hour at 225° C. and then 2 hours at 250° C. The physical and electrical properties of the cured product are given in Table I.
COMPARATIVE EXPERIMENT C
Blending of Resins
77.7 grams of the reaction product of vinyl benzyl chloride and tetrabromobisphenol A (Component D) are blended with 329.3 grams of a cyanate ester resin (Component A) preheated to 100° C. The resulting product contains approximately 8% bromine.
Casting and Curing of Resin Blend
To this heated mixture is added 4.54 grams of a catalyst solution. The catalyst solution is made by dissolving 1.5 grams of cobalt (III) acetylacetonate in 28.5 grams of divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into an aluminum mold, the internal surfaces of which are treated with a 5% by wt. solution of Dow Corning 20 silicone oil in isopropanol as a mold release agent. The mold is placed in an oven preheated to 175° C. After one hour, the temperature is raised to 225° C. for one hour, followed by 2 hours at 250° C. The physical and electrical properties of the cured product are given in Table I.
COMPARATIVE EXPERIMENT D
Blending of Resins
160 grams of 60% by wt. brominated vinyl ester resin in styrene (Component E) are blended with 304 grams of a cyanate ester resin (Component A). The mixture is placed in a vacuum oven for 3.5 hours at 72° C. to 84° C. to remove the styrene. The vacuum is approximately 29 to 30 inches Hg. The product is stored in a freezer until used. The product is transferred to a round bottom stripping flask and is stripped on a rotary evaporator at 80° C. to 85° C. under a vacuum (10 mm Hg). The resulting product contains approximately 8% bromine.
Casting and Curing of Resin Blend
To this heated mixture is added 4.54 grams of a catalyst solution, containing 5% by wt. cobalt (III) acetylacetonate in divinylbenzene. The resin-catalyst blend is well mixed, then degassed on the rotary evaporator under vacuum. The degassed material is poured into an aluminum mold, the internal surfaces of which are treated with a 5% by wt. solution of Dow Corning 20 silicone oil in isopropanol as a mold release agent. The mold is placed in an oven preheated to 175° C. After one hour, the temperature is raised to 225° C. for two hours. The physical and electrical properties of the cured product are given in Table I.
COMPARATIVE EXPERIMENT E
Blending of Resins
57.0 grams of brominated polycarbonate (Component G) are dissolved in 250 ml of tetrahydrofuran and poured into a round bottom flask containing 343 grams of a cyanate ester resin (Component A). The mixture is heated under vacuum (8 mm Hg) on a rotary evaporator at a maximum temperature of 170° C. for approximately one hour. The resulting product contains approximately 8% bromine.
Casting and Curing of Resin Blend
The above material is then poured into an aluminum mold, the internal surfaces of which are treated with a 5% by wt. solution of Dow Corning 20 silicone oil in isopropanol as a mold release agent. The mold after sitting overnight at room temperature is placed in an oven preheated to 175° C. After one hour, the temperature is raised to 225° C. for one hour, followed by 2 hours at 250° C. The moisture resistance and electrical properties of the cured product are given in Table I.
COMPARATIVE EXPERIMENT F
400 grams of a cyanate ester resin (Component A) are heated in a 140° C oven. To this is added 10.0 grams of a catalyst solution. The solution is made by dissolving 2.25 grams of cobalt (III) acetylacetonate in 35 grams of divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into a preheated (175° C.) glass mold, the internal surfaces of which have been treated with Release All #30 as a mold release agent. The mold is placed in an oven preheated to 177° C. After 1 hour, the temperature is raised to 250° C. and held for two hours. The electrical, thermal, and moisture resistance properties are given in Table I.
COMPARATIVE EXPERIMENT G
140 grams of a cyanate ester resin (Component H) are heated in a 130° C. oven. To this is added 3.5 grams of a catalyst solution. The solution is made by dissolving 0.835 gram of cobalt (III) acetylacetonate in 13 grams of divinylbenzene. The resin-catalyst blend is well mixed, then degassed under a bell jar using vacuum. The degassed material is poured into a preheated (177° C.) aluminum mold, the internal surfaces of which have been treated with a 5% by wt. solution of Dow Corning DC-20 silicone oil in isopropanol as a mold release agent. The mold is placed in an oven preheated to 177° C. for one hour, followed by four hours at 225° C. After several days, the casting is postcured at 250° C. for two hours. The electrical, thermal, and moisture resistance properties are given in Table I.
TABLE I__________________________________________________________________________ EXAMPLE NUMBER OR COMPARATIVE EXPERIMENT LETTER__________________________________________________________________________PROPERTY Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6__________________________________________________________________________Component, A, 86.9 A, 80.3 A, 86.9 A, 72.9 H, 70.1 A, 80% by weight B, 13.1 B, 19.7 B, 13.1 G, 27.1 I, 29.9 L, 20% Br in formulation 8 12 8 18.4 18 12Flex. Str..sup.1psi -- -- 15,846 -- -- --MPa 109 1Flex. Mod..sup.2psi -- -- 499,744 -- -- --MPa 3,443Tensile Str..sup.3psi -- -- 10,874 -- -- --MPa 75Tensile Mod..sup.4psi -- -- 466,769 -- -- --MPa 3,216% Elongation.sup.5 -- -- 3.0 -- -- --Dielect. Constant.sup.6Initial -- -- 2.91 2.83 2.94 2.78After Moist. Exp..sup.7 3.35 3.49 3.58* 3.26Tg (DSC), °C..sup.8 -- -- 255 259.9 >270 264Tg (TMA) °C..sup.9 -- -- 241 -- -- 230UL 94 Flame V0** V1** -- -- -- --Rating.sup.10Onset of -- -- 424.6 -- -- 418Degredation, °C..sup.12Moisture 1.93* 1.29Resistance, % Wt.Gain.sup.7__________________________________________________________________________ *100 hours in autoclave instead of 500 hours. **This numberical rating is for comparative purposes only and is not an indication of how the composition might perform under actual fire conditions.PROPERTY A* B* C* D* E* F* G*__________________________________________________________________________Component, A, 100 A, 81.7 A, 80.6 A, 76 A, 85.7 A, 100 H, 100% by weight C, 18.3 D, 19.4 E, 24 F, 14.3% Br in None 8 8 8 8 None NoneformulationFlex. Str..sup.1psi 17,695 17,613 16,694 17,860 18,694 -- --MPa 122 121 115 123 129Flex. Mod..sup.2psi 465,718 514,842 513,825 501,824 492,372 -- --MPa 3,209 3,547 3,540 3,458 3,392Tensile Str..sup.3psi 9,923 11,804 9,486 9,902 10,248 -- --MPa 68 81 65 68 71Tensile Mod..sup.4psi 489,918 501,693 486,040 472,234 494,343 -- --MPa 3,376 3,457 3,349 3,254 3,406% Elongation.sup.5 2.2 3.0 2.3 2.3 2.7 -- --Dielect. Constant.sup.6Initial 2.86 2.84 2.98 2.87 2.87 2.80 2.97After Moist. Exp..sup.7 3.47 3.17 3.85 3.33 Broke.sup.11 3.35 3.72*Tg (DSC), °C..sup.8 263 244 258 233 255 269 >270Tg (TMA) °C..sup.9 241 223 224 206 237 246 --UL 94 Flame -- -- -- -- -- -- --Rating.sup.10Onset of 421.4 418.9 326.9 335.8 371.4 433 --Degredation, °C..sup.12Moisture -- 1.71 2.48**Resistance, % wt.gain.sup.7__________________________________________________________________________ *Not an example of the present invention. **100 hours in autoclave instead of 500 hours. Footnotes to Table I. .sup.1 Flexural strength determined by ASTM D790 (1984) on 1" × 3" × 1/8" (25.4 mm × 76.2 mm × 3.2 mm) coupons. .sup.2 Flexural modulus determined by ASTM D790 (1984) on 1" × 3" × 1/8" (25.4 mm × 76.2 mm × 3.2 mm) coupons. .sup.3 Tensile strength determined by ASTM D638 (1984). .sup.4 Tensile modulus determined by ASTM D638 (1984). .sup.5 Elongation determined by ASTM D638 (1984). .sup.6 Electrical properties determined on 33/8" × 3" × 1/8" (85.7 mm × 76.2 mm × 3.2 mm) specimens. The surfaces are wipe with acetone prior to testing on a Gen Rad Precision 1689 RLC Digibridge equipped with a LD3 specimen cell. .sup.7 Determined after sample is exposed in an autoclave containing a pa of water at 15 psig (103.4 kPa) and 250° F. (121.1° C.) for 500 hours. .sup.8 Glass transition temperature determined by differential scanning calorimetry (DSC). .sup.9 Glass transition temperature determined by thermal mechanical analysis (TMA). .sup.10 Determined by Underwriters Laboratory UL 94 Flame spread test. .sup.11 The coupon broke before property could be determined. .sup.12 Onset of thermal degradation is determined by thermal gravimetric analysis (TGA). Cured samples are run on a Dupont 1090 Thermal analyzer equipped with a TGA module #951 with a 200 cc/min. flow of N.sub.2. The temperature is increased at a rate of 10° C./min.
EXAMPLE 7
4000 grams of cyanate ester resin (Component A) are dissolved in 1600 grams of dimethylformamide and 100 grams of methyl ethyl ketone. To this solution are added 840 grams brominated polystyrene (Component G). To this solution are added 32 grams of a 10% catalyst mixture of zinc octoate. This solution is well mixed for one hour on horizontal shaking device. This solution varnish is then used to preimpregnate 7628 style fiber glass and is heated to 350° F. (160° C.) for 2.5 minutes. These B-staged prepregs are then cut into 12"×12" (304.8×304.8 mm) sheets. These sheets are then stacked (eight in a book) and placed in 14"×14" (355.7×355.6 mm) lamination press. The press is operated with the following pressing parameters:
Step 1:
Temperature =200° F. (93.3° C.)
Force=72,000 pounds (32,659 kg)
Step 2:
Temperature is ramped from 200° F. to 290° F. (93.3° C.-143.3° C.) at a rate of 4° F. (2.2° C.)/min.
Force held constant at 72,000 pounds (32,659 kg).
Step 3:
Temperature is ramped from 290° F. to 350° F. (143.3° C.-176.7° C.) at a rate of 20° F./min.
Force held constant at 72,000 pounds (32,659 kg).
This condition is held constant for a duration of one hour.
Step 4:
Temperature is ramped from 350° F. to 200° F. (176.7° C.-93.3° C.) at a rate of 8° F. (4.4° C.)/min.
Step 5:
Force is reduced to zero applied pounds.
The cured laminate is then post-baked at 225° C. in a convection oven. The physical and electrical properties of the cured product are given in Table II.
EXAMPLE 8
4000 grams of cyanate ester resin (Component A) are dissolved in 1680 grams of dimethylformamide and grams of methyl ethyl ketone. To this solution are added 1000 grams brominated polystyrene (Component J). To this solution are added 18 grams of a 10% catalyst mixture of zinc octoate. This solution is well mixed for one hour on horizontal shaking device. This solution varnish is then used to preimpregnate 7628 style fiber glass and is heated to 350° F. (176.7° C.) for 2.5 minutes. These B-staged prepregs are then cut into 12"×12" (304.8×304.8 mm) sheets. These sheets are then stacked (eight in a book) and placed in 14×14" (355.6×355.6 mm) lamination press. The press is operated with the following pressing parameters:
Step 1:
Temperature=200° F. (93.3° C.)
Force=72,000 pounds (32,659 kg).
Step 2:
Temperature is ramped from 200° F. to 290° F. (93.3° C.-143.3° C.) at a rate of 4° F./min. Force held constant at 72,000 pounds (32,659 kg).
Step 3:
Temperature is ramped from 290° F. to 350° F. (143.3° C.-176.7° C.) at a rate of 20° F./min.
Force held constant at 72,000 pounds (32,659 kg). This condition is held constant for a duration of one hour.
Step 4:
Temperature is ramped from 350° F. to 200° F. (176.7° C.-93.3° C.) at a rate of 8° F./min.
Step 5:
Force is reduced to zero applied pounds.
The cured laminate is then post-baked at 225° C. in a convection oven. The physical and electrical properties of the cured product are given in Table II.
EXAMPLE 9
4000 grams of cyanate ester resin (Component A) are dissolved in 1640 grams of dimethylformamide and grams of methyl ethyl ketone. To this solution are added 960 grams brominated polystyrene (Component B). To this solution are added 9.2 grams of a 10% catalyst mixture of zinc octoate. This solution is well mixed for one hour on horizontal shaking device. This solution varnish is then used to preimpregnate 7628 style fiber glass and is heated to 350° F. (176.7° C.) for 2.5 minutes. These B-staged prepregs are then cut into 12"×12" (304.8×304.8 mm) sheets. These sheets are then stacked (eight in a book) and placed in 14"×14" (355.6×355.6 mm) lamination press. The press is operated with the following pressing parameters:
Step 1:
Temperature=200° F. (93.3° C.)
Force=72,000 pounds (32,659 kg)
Step 2:
Temperature is ramped from 200° F. to 290° F. (93.3° C.-143.3° C.) at a rate of 4° F. (2.2° C.)/min.
Force held constant at 72,000 pounds (32,659 kg).
Step 3:
Temperature is ramped from 290° F. to 350° F. (143.3° C.-176.7° C.) at a rate of 20° F. (11.1° C.)/min.
Force held constant at 72,000 pounds (32,659 kg). This condition is held constant for a duration of one hour.
Step 4:
Temperature is ramped from 350° F. to 200° F. (176.7° C.-93.3° C.) at a rate of 8° F. (4.4° C.)/min.
Step 5:
Force is reduced to zero applied pounds.
The cured laminate is then post-baked at 225° C. in a convection oven. The physical and electrical properties of the cured product are given in Table II.
EXAMPLE 10
1600 grams of cyanate ester resin (Component A) are dissolved in 656 grams of dimethylformamide and 282 grams of methyl ethyl ketone. To this solution are added 400 grams brominated polystyrene (Component L). To this solution are added 51.4 grams of a 1.0% catalyst mixture of zinc octoate. This solution is well mixed for one hour on horizontal shaking device. This solution varnish is then used to pr impregnate 7628 style fiber glass and is heated to 350° F. (176.7° C.) for 2.5 minutes. These B-staged prepregs are then cut into 12"×12" (304.8 mm×304.8 mm) sheets. These sheets are then stacked (eight in a book) and placed in 14"×14" (355.6 mm×355.6 mm) lamination press. The press is operated with the following pressing parameters:
Step 1:
Temperature=200° F. (93.3° C.)
Force=72,000 pounds (32,659 kg)
Step 2:
Temperature is ramped from 200° F. to 290° F. (93.3° C. to 143.3) at a rate of 4° F. (2.22° C.)/min.
Force held constant at 72,000 pounds (32,659 kg).
Step 3:
Temperature is ramped from 290° F. to 350° F. (143.3° C. to 176.7° C.) at a rate of 20° F./min.
Force held constant at 72,000 pounds (32,659 kg).
This condition is held constant for a duration of one hour.
Step 4:
Temperature is ramped from 350° F. to 200° F. (176.7° C. to 93.3° C.) at a rate of 8° F. (4.4° C./min.)
Step 5:
Force is reduced to 0 applied pounds.
The cured laminate is then post-baked for two hours at 225° C. in a convection oven.
The physical and electrical properties of the cured product are given in Table II.
COMPARATIVE EXPERIMENT H
5000 grams of cyanate ester resin (Component A) are dissolved in 1665 gram of dimethylformamide and 200 grams of methyl ethyl ketone. To this solution are added 12.5 grams of a 10% catalyst mixture of zinc octoate. This solution is well mixed for one hour on horizontal shaking device. This solution varnish is then used to preimpregnate 7628 style fiber glass and is heated to 350° F. (176.7° C.) for 2.5 minutes. These B-staged prepregs are then cut into 12×12" (304.8×304.8 mm) sheets. These sheets are then stacked (eight in a book) and placed in 14"×14" (355.6×355.6 mm) lamination press. The press is operated with the following pressing parameters:
Step 1:
Temperature=200° F. (93.3° C.)
Force=72,000 pounds (32,659 kg)
Step 2:
Temperature is ramped from 200° F. to 290° F. (93.3° C.-143.3° C.) at a rate of 4° F. (2.2° C.)/min.
Force held constant at 72,000 pounds (32,659 kg).
Step 3:
Temperature is ramped from 290° F. to 350° F. (143.3° C.-176.7° C.) at a rate of 20° F. (11.1° C.)/min.
Force held constant at 72,000 pounds (32,659 kg).
This condition is held constant for a duration of one hour.
Step 4:
Temperature is ramped from 350° F. to 200° F. (176.7° C.-93.3° C.) at a rate of 8° F. (4.4° C.)/min.
Step 5:
Force is reduced to zero applied pounds.
The cured laminate is then post-baked at 225° C. in a convection oven. The physical and electrical properties of the cured product are given in Table II.
COMPARATIVE EXPERIMENT I
3200 grams of brominated epoxy resin (Component K) are dissolved in 800 grams of acetone. To this solution are added 86 grams of dicyandiamide dissolved in a solution of 389 grams of ethylene glycol methyl ether and 389 grams of dimethylformamide. To this resin solution are added 32 grams of a 10% catalyst solution in dimethylformamide. This solution is well mixed for one hour on a horizontal shaking device. This solution varnish is then used to preimpregnate 7628 style fiber glass and is heated to 350° F. (176.7° C.) for 2.5 minutes. These B-staged prepregs are then cut into 12"×12" (304.8×304.8 mm) sheets. These sheets are then stacked (eight in a book) and placed in 14" ×14" (355.6×355.6 mm) lamination press. The press is operated with the following pressing parameters:
Step 1:
Temperature=200° F. (93.3° C.)
Force=72,000 pounds (32,659 kg)
Step 2:
Temperature is ramped from 200° F. to 290° F. (93.3° C.-143.3° C.) at a rate of 4° F. (2.2° C.)/min.
Force held constant at 72,000 pounds (32,659 kg).
Step 3:
Temperature is ramped from 290° F. to 350° F. (143.3° C.-176.7° C.) at a rate of 20° F. (11.1° C.)/min.
Force held constant at 72,000 pounds (32,659 kg).
This condition is held constant for a duration of one hour.
Step 4:
Temperature is ramped from 350° F. to 200° F. (176.7° C.-93.3° C.) at a rate of 8° F. (4.4° C.)/min.
Step 5:
Force is reduced to zero applied pounds.
No additional post-cure was performed. The thermal and electrical properties of the cured product are given in Table II.
TABLE II______________________________________Example or Comparative ExperimentEx. 7 Ex. 8 Ex. 9 Ex. 10 C.E. H* C.E. I*______________________________________Glass 213 231 237 225 243 132TransitionTemp., °C.Coefficient 53 90 79 77 47 72of ThermalExpansion,ppm/°C.Dielectric 3.8 3.7 3.9 3.7 .sub. 3.9 5.1ConstantDissapation 0.0022 0.0036 0.0028 0.002.sub.-- 0.0035 0.0193Factor______________________________________ *Not an example of the invention. | The fire retardant properties of polycyanates are improved by blending them with a brominated homopolymer or brominated interpolymer of styrene or alkyl- or halo-substituted styrene without an unacceptable sacrifice in the physical, thermal, electrical and moisture resistance properties. | 2 |
FIELD
Embodiments described herein encompass a method of improving plant growth responses, reducing nitrogen input, and improving plant development by application of a plant bio-stimulant composition in combination with urea and/or other agricultural compounds. A method for combining the composition with urea and/or other agricultural compounds is also encompassed. Embodiments described herein further encompass a bio-stimulant composition for obtaining improved plant growth, either combined or uncombined with urea and/or other agricultural compounds.
BACKGROUND
New Zealand has traditionally relied on clover and other legumes to biologically fix the nitrogen that is required to grow pasture. More recently, there has been increased use of nitrogen fertilisers such as urea to increase pasture production further and address seasonal deficits in feed supply.
There are a number of negative environmental consequences of excessive use of nitrogen fertilisers. The one that is most publicised is the potential to increase the level of nitrates that are leached into groundwater and can therefore pollute waterways. There are also implications relevant to the concern over greenhouse gases. The use of high amounts of nitrogen fertiliser can increase the level of denitrification that can occur leading to higher levels of nitrous oxide emissions (a potent greenhouse gas). Furthermore, the production of artificial nitrogen fertiliser is highly energy intensive; this energy requirement is derived from the burning of natural gas resulting in the production of the other greenhouse gas, carbon dioxide. This also represents a significant use of a limited natural gas resource increasingly important for other uses including electricity generation.
Use of nitrogen fertiliser is steadily increasing. In New Zealand, a country with an economy that relies heavily on dairy, sheep and beef farming, total fertiliser use increased by 113 percent from 1986 to 2002 (Statistics New Zealand, Fertiliser use and the environment, August 2006). The application of urea increased by approximately 27 percent between 2002 and 2004 (ibid.).
A problem with the application of nitrogen fertilisers is that often excess nitrogen is applied to the pasture. In addition, if nitrogen is not applied at the correct time, for example, if it is applied when plants are not actively growing, the loss of nitrogen is exacerbated. There are several approaches that have been taken to minimise adverse effects of fertiliser use. One such approach is the use of nitrification inhibitors.
The most common nitrification inhibitors are 2-chloro-6(trichloromethyl)pyridine, dicyandiamide and 3,4-dimethylpyrazole-phosphate. Such inhibitors act to reduce nitrate leaching and nitrogen oxide emissions. Plant growth is increased. However, the effects can be variable and depend on timing of application, amount of nitrogen fertiliser applied and physical factors such as soil temperature, moisture, and pH.
Urease inhibitors have also been used to prevent loss of nitrogen to the atmosphere by volatilisation as ammonia. Urease inhibitors act by slowing the rate of hydrolysis. Other ways of reducing nitrogen loss are through farm management practices, including timing of application of fertiliser, split fertiliser applications, grazing management, pasture species choices, cropping type and landscape modification.
However, there remains a need for new products and methods for improving plant growth responses and development, while reducing nitrogen input.
SUMMARY
Embodiments described herein encompass a microbial bio-stimulant composition that has been shown to increase pasture productivity alone and in conjunction with the use of solid nitrogen fertiliser. The mode of action includes stimulating nitrogen uptake and amino acid synthesis.
It is an object of embodiments described herein to provide a means for stimulating plant growth with up to 50% less urea, or at least provides a useful alternative to other means of stimulating plant growth.
In one aspect, a method of improving plant growth by application of a bio-stimulant composition either combined or uncombined with urea and/or other agricultural compounds is provided. The method may also be used to reduce nitrogen input and improve plant development. The agricultural compounds may be urea, fertilisers, foliar fertilisers, herbicides, insecticides, fungicides, or mineral solutions.
In another aspect, a bio-stimulant composition for improving plant growth either combined or uncombined with urea and/or other agricultural compounds is provided. The composition may also be used to reduce nitrogen input and improve plant development. The agricultural compound may be urea, fertiliser, herbicide, insecticides, fungicides or foliar fertilisers or mineral solutions.
In a particular aspect, the bio-stimulant composition comprises a fermentation broth comprising one or more species or strains of microorganisms which have been grown in the fermentation broth and then killed or lysed to produce a mixture of cellular components in the fermentation broth (e.g., lysed fermentation broth).
In a further aspect, a method for combining the bio-stimulant composition described herein with urea and/or other agricultural compounds is provided. In one particular aspect, the method comprises dissolving urea in water and adding the bio-stimulant composition to the solution. This can be applied to the plants to achieve more even application (e.g., via spraying) than is possible with granular application of urea. This can also take advantage of the increases foliar uptake and decreased foliage nitrate levels of the bio-stimulant composition.
In a still further aspect, a formulation combining the bio-stimulant composition described herein with urea and/or other agricultural compounds is provided. The formulation can comprise dissolved urea added to the bio-stimulant composition. This formulation can be adapted, for example, for foliar applications (e.g., foliar sprays or drips). The formulation can be used to improve plant growth.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments are described with reference to specific embodiments thereof and with reference to the figures.
FIG. 1 : Field testing results for the bio-stimulant composition (Donaghys LessN® 40) compared to sprays containing the same amount of urea (U 40) and double the amount of urea (U 80) at Day 23.
DETAILED DESCRIPTION
The bio-stimulant is produced by fermentation of a single species or combination of microorganisms including but not limited to lactic acid bacteria and yeasts that are then killed or lysed. Any microorganism or combinations of microorganisms capable of fermentation can be used in accordance with the embodiments described herein. The fermentation can involve growing a liquid broth that includes carbohydrate and mineral sources for the microorganisms. Any fermentation media can be used, and many suitable media are well known in the art.
Bacteria useful for the embodiments described herein include but are not limited to Lactobacillus plantarum, Streptococcus thermophilus (also called Streptococcus salivairus ) and Propionibacter freudenreichii . Embodiments encompass various species of Lactobaccilius, Streptococcus , and Propionibacter . As further examples, the invention encompasses Lactobacillus acidophilus, Lactobacillus buchneri, Lactobacillus johnsonii, Lactobacillus murinus, Lactobacillus paraplantarum, Lactobacillus pentosus, Lactobacillus delbrueckii, Lactococcus lactis, Leuconostoc oenos, Bifidobacter bifidus, Propionibacter shermani, Propionibacter pelophilus , and Propionivibro limicola.
Yeasts useful for the embodiments described herein include but are not limited to Saccharomyces cerevisiae . The embodiments encompass various species of Saccharomyces . As further examples, the embodiments encompass Saccharomyces pastorianus, Saccharomyces boulardii, Saccharomyces bayanus, Saccharomyces exiguous, Saccharomyces pombe , as well as species of Candida, Pichia, Hanseniaspora, Metschnikowia, Issatchenkia, Kluyveromyces , and Kloeckera.
In accordance with embodiments described herein, the microorganisms produce a range of growth promoting compounds including cytokinins, betaines, gibberellins and antioxidants. There is also a range of amino acids, oligopeptides and cell fragments resulting from the lysis of the microorganisms. In particular aspects, the microorganisms can be grown in the media to concentrations of about 10 4 cfu/ml, about 10 5 cfu/ml, about 10 6 cfu/ml, about 10 7 cfu/ml, about 10 8 cfu/ml, about 10 9 cfu/ml, about 10 10 cfu/ml, about 10 11 cfu/ml, about 10 12 cfu/ml, about 10 13 cfu/ml, about 10 14 cfu/ml, or in a range of about 10 6 to about 10 10 cfu/ml, or about 10 7 cfu/ml to about 10 9 cfu/ml.
The microorganisms can be killed or lysed by various means, for example, by freezing, heating, bead beating, detergents including non-ionic and zwitterionic detergents, low pH treatment including by hydrochloric, hydrofluoric and sulphuric acids, and high pH treatment including by sodium hydroxide. Also included is enzymatic lysis including but not limited to one or more of types of cellulase, glycanase, lysozyme, lysostaphin, mannase, mutanolysin, protease and zymolase enzymes.
Included also is solvent treatment such as with sodium dodecyl sulfate treatment followed by acetone solvent use, or ultrasonic treatment. Further included are means which increase pressure followed by a rapid decrease in pressure such as is achievable with a pressure bomb, cell bomb, or with processors that provide high shear pressure such as valve type processors including but not limited to French pressure cell press or rotor-stator processors or fixed geometry fluid processors.
The compositions and formulations described herein can be applied to plants by various means, including sprays, sprinklers, drips, dips, drenches, dressings, oils, and any, type of irrigation system. As non-limiting examples, embodiments encompass foliar sprays, turf sprays, in-furrow sprays, root dips, root drenches, stem drenches, seedling drenches, tuber drenches, fruit drenches, soil drenches, soil drips, and soil injections. As further examples, the compositions and formulations can be applied in dry form, e.g., granules, microgranules, powders, pellets, sticks, flakes, crystals, and crumbles.
For formulations, the bio-stimulant composition can be combined with urea, e.g., for concentrations of urea at about 0.1 kg/L, about 0.12 kg/L, about 0.15 kg/L, about 0.18 kg/L, about 0.2 kg/L, about 0.22 kg/L, about 0.25 kg/L, about 0.28 kg/L, about 0.3 kg/L, about 0.35 kg/L, about 0.38 kg/L, about 0.4 kg/L, about 0.42 kg/L, about 0.45 kg/L, about 0.48 kg/L, or about 0.50 kg/L, or in a range of about 0.15 kg/L to about 0.25 kg/L, or about 0.18 kg/L to about 0.22 kg/L, or about 0.35 kg/L to about 0.45 kg/L, or about 0.38 kg/L to about 0.42 kg/L.
The composition described herein can be used to stimulate plant growth and the plant immune system. It can be used to overcome periods of plant stress. In particular, the bio-stimulant composition described herein can be used to assist the plant to achieve more efficient nutrient utilisation. The composition described herein is understood to act as a biological growth promoter that assists pasture production through the stimulation of plant photosynthesis, proliferation of the fine feeder roots and subsequent increased nutrient uptake.
The bio-stimulant composition can be applied at a time when soil temperatures are conducive to pasture or crop growth response. The composition can be applied by diluting by a factor of at least one in ten and can be distributed by spraying or through irrigation. The bio-stimulant composition can be used for improving pasture growth and is also useful on a wide range of crops.
The composition described herein may comprise a range of naturally produced and balanced growth promotion factors. The principal precursors are forms of cytokinin (a microbial and plant hormone responsible for promoting cell division and growth), betaines (substances used by plant cells for protection against osmotic stress, drought, high salinity or high temperature) and oligopeptides (short chains of amino acids that improve nutrient uptake through cell membranes). Although plants produce their own cytokinin, production may be restricted when the plant is under stress.
The use of the composition described herein enhances nitrogen utilisation. It has also been shown to encourage white clover growth relative to perennial ryegrass. This has benefits because of the high feed value of white clover and the importance of root nodules of this plant in fixing atmospheric nitrogen so that more nitrogen is available for use by the plant itself and other pasture plants. In addition, the use of the composition described herein reduces the amount of urea that needs to be applied. This benefits the clover component of pasture because higher rates of nitrogen can potentially reduce nitrogen fixation rates of clover and also favours grass growth over clover growth.
EXAMPLES
The examples described herein are for purposes of illustrating embodiments described herein. Other embodiments, methods, and types of analyses are within the scope of persons of ordinary skill in the molecular diagnostic arts and need not be described in detail hereon. Other embodiments within the scope of the art are considered to be part of the embodiments described herein.
Example 1
Fermentation Broth
The bacteria Lactobacillus plantarum, Streptococcus thermophilus and Propionibacter freudenreichii and the yeast Saccharomyces cerevisiae were isolated and maintained using standard methods known in the art. A broth medium was prepared using Diffco™ Lactobacilli MRS Broth augmented with the following ingredients.
TABLE 1
Fermentation broth composition (all ingredients per litre of broth)
DiffcoTM Lactobacilli MRS Broth
55
g
Urea
2
g
Carrot Juice
1.25
mL
Molasses powder from sugar cane
2.5
g
The broth was prepared by constant stirring while bring to the boil and keeping there for one minute. This ensured full dissolving of the broth medium, urea and molasses.
The broth was then sterilised in autoclave (121° C. for 15 mins) and poured into a sterilised 20 L bioreactor. After the broth was cooled to about 35° C., pure cultures of the three bacterial species (minimum of 10 6 colony forming units or cfu s for each species) and one yeast species (minimum 10 4 cfu's) were then added to the broth using standard sterile technique known in the art to avoid contamination with other microbial species. The fermentation was run for 12 days at 35° C. by which stage there were at least 10 8 cfu per mL of the dominant species Lactobacillus plantarum.
The fermentation broth was then placed in a fixed geometry fluid processor for cell lysis of the microorganisms. Two passes were required with the broth being cooled in between passes to compensate for the temperature increase due to pressurisation and release. The process was optimised for pressure to a maximum of 200 MPa.
Example 2
Preparation of the Formulation with Dissolved Urea
Urea fertiliser prills were dissolved in water at a concentration of 40 kg urea per 197 L total volume. Dissolution was aided by agitation of the water without a requirement for heating the water.
The dissolving of urea is an endothermic process and the time taken to dissolve depends on the concentration of urea and total volume involved as well as the initial temperature of the water and the method of agitation. With constant stirring and an initial water temperature of 12° C., the complete dissolution of urea (sourced from Ballance Agri-nutrients Limited, Tauranga New Zealand) at the above concentration and volume took 7 minutes. Source and amount of hardener added to urea prills in their manufacture are likely to affect the speed of dissolution in water.
The dissolved urea solution had a pH of around 9.0. The majority of the nitrogen, however, was found to remain in the organic form. Titrametric determination as known in the art revealed only 0.004% ammonium nitrogen and 0.002% nitrate nitrogen expressed in terms of grams of these forms per 100 mL of solution.
Once the urea was fully dissolved, lysed fermentation broth as prepared in Example 1 was added at a rate of 3 L broth to 197 L volume of urea solution. As the broth had an acidic pH of 3.6 due largely to the presence of organic acid fermentation products, the pH of the total solution was brought closer to neutral to a pH of around 6.2. Both the dissolved urea and the comparatively small amount of broth had a low buffering effect on solution pH.
The prepared solution was then ready to be applied to pasture or suitable crops.
Example 3
Field Experiment Utilising the Formulation on Pasture in Conjunction with Dissolved Urea Fertiliser
Introduction: The field trial's objective was to identify if Donaghys LessN® (3 L/ha) applied in combination with 40 kg/ha urea (18 kg N), would increase the pasture dry matter (DM) response to a level equivalent to 80 kg/ha urea (37 kg N/ha). Pasture DM accumulation was measured by Grass Master (GM) probe on Day one (pre-treatment, start point) and 21 Days after treatment application. The GM Probe estimated DM accumulation using pre-programmed calibration equation provided by the manufacturer.
Methodology: A dairy farm property with irrigation was selected in mid-Canterbury region of New Zealand in December 2007. A recently grazed paddock with even pasture cover was selected to reduce variability between plots. The paddock was in re-growth phase having just been grazed by stock. Livestock were excluded from the trial area during the trial period.
A complete randomised block design (CRBD) consisting of 4 treatments ( FIG. 1 ) with 5 replicate plots used for each treatment. This provided a total of 20 plots, which was divided into 5 blocks. Within each block one replicate of all 5 treatments was randomly assigned.
Within each block, treatments were randomly allocated to plots, using a random number generator. Plots were 4 m wide by a 100 m long. The spray boom was 4 m wide. Plots were marked with 60 cm long flags, at 0, halfway and full length.
Pre-treatment pasture dry matter was estimated for each plot by using the Grass Master Probe. Measurements were taken on every other pace one way up the plot length, randomly dropping probe to near where foot falls but at least 15 cm away from body to avoid false reading. This resulted in around 50-65 readings for each plot. Individual readings were spoken into an audio recorder and later listened and entered into Excel sheet for analysis. Readings were taken in each plot without knowledge of what the plot treatment is to eliminate risk of bias. The probe was set to “slow” reading (i.e. takes around 3 seconds to read). The probe was left stable for each reading until it emitted a beep. Average pasture cover recorded on the first day was used as the baseline for each plot from which growth was based.
The spray tank was cleaned and the nozzles checked. The spray pump is set at 30 psi. The spray rig was calibrated, using containers to collect volume of spray over time information from each nozzle, to deliver 200 L per hectare equivalent using the amount of time to deliver given volume of water and maintaining an appropriate speed (10 km/hour).
Control: Fifty 50 liters of water was added to the spray tank. The pump was started 1-2 m prior to plot perimeter and the vehicle was driven steadily at the determined speed (around 10 km/hour) over each control plot. The tank was then emptied.
U40-(Dissolved Urea sprayed at 40 kg urea/ha): Twenty liters of water was added to the spray tank and then 10 kg or urea prills was added. The water was stirred until all urea dissolved. The tank was then topped up with approximately 23 L of water to make a total volume of 50L. The nozzles where checked again for correct operating and the pressure set at 30 psi. The pump was started 1-2 m prior to plot perimeter and the vehicle was driven steadily at the determined speed (around 10 km.hour) over each U40 plot. The tank was then emptied and rinsed with water.
Donaghys LessN® 40-(Dissolved Urea sprayed at 40 kg urea/ha with 3 L of the broth called Donaghys LessN®: Twenty liters of water was added to the spray tank andthen 10 kg of urea prills was added. The water was stirred until all urea dissolved. Fermentation broth was at 0.75 L to the solution and then the tank was topped up with approximately 22.25 L of water to make a total volume of 50 L. The nozzles where checked again for correct operating and the pressure set at 30 psi. The pump was started 1-2 m prior to plot perimeter and the vehicle was driven steadily at the determined speed (around 10 km.hour) over each Donaghys LessN® 40 plot. The tank was then emptied and rinsed with water.
U80-(Dissolved Urea sprayed at 80 kg urea/ha): Thirty five liters of water was added to the spray tank and then 20 kg or urea prills was added. The water was stirred until all urea dissolved which took about 25 minutes. The tank was then topped up with approximately one liter of water to make a total volume of 50 L. The nozzles where checked again for correct operating and the pressure set at 30 psi. The pump was started 1-2 m prior to plot perimeter and the vehicle was driven steadily at the determined speed (around 10 km.hour) over each U80 plot. The tank was then emptied and rinsed with water.
Post Treatment-Pasture DM Measurements: Post-treatment pasture dry matter was assessed 23 days after treatment by using a Grass Master Probe using the methods described for pre-treatment readings.
Statistical Analysis: Data analysis was performed in Genstat using analysis of variance (ANOVA) in CRBD. The level of significance of treatment differences was assessed.
Results: Pasture growth was calculated from subtracting the relevant baseline pasture dry matter measurement from the pasture dry matter measurement at the end of each of the three grazing rotations. Donaghys LessN® 40 performed similarly to Urea 80 and both these treatments caused statistically significantly greater pasture growth than Urea 40 (which was not statistically significantly better than Control).
TABLE 2
Pasture dry matter production (kg/ha)
Treatment
DM Rotation 1*
Control
1322 a
Urea 40
1527 a
Urea 80
1979 b
Donaghys LessN ® 40
1809 b
a,b Numbers with a different letter beside them are statistically significantly different from each other (p < 0.05)
All publications and patents mentioned in the above specification are herein incorporated by reference. Any discussion of the publications and patents throughout the specification should in no way be considered as an admission that such constitute prior art, or widely known or common general knowledge in the field.
Where the foregoing description reference has been made to integers having known equivalents thereof, those equivalents are herein incorporated as if individually set forth. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. It is appreciated that further modifications may be made to the invention as described herein without departing from the scope of the invention. The invention illustratively described herein may be practiced in the absence of any element or elements, or limitation or limitations, which are not specifically disclosed herein as essential.
In addition, in each instance herein, in embodiments or examples of the present invention, the terms ‘comprising’, ‘including’, etc. are to be read expansively without limitation. Thus, unless the context clearly requires otherwise, throughout the description and the claims, the words ‘comprise’, ‘comprising’ and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say in the sense of “including but not limited to”. | A bio-stimulant composition for obtaining improved plant growth, either combined or uncombined with urea and/or other agricultural compounds, as well of methods of producing and using said composition. | 2 |
This application is a Continuation of Ser. No. 08/167,002, filed Dec. 15, 1993, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates generally to frequency and protocol agile, wireless communication devices and systems adapted to enable voice and/or data transmission to occur using a variety of different radio frequencies, transmission protocols and radio infrastructures.
Many communication industry experts believe that a personal information revolution has begun that will have as dramatic an impact as did the rise of personal computers in the 1980's. Such experts are predicting that the personal computer will become truly "personal" by allowing virtually instant access to information anytime or anywhere. There exists no consensus, however, on the pace or form of this revolution.
For example, the wireless communication industry is being fragmented by the emergence of a substantial number of competing technologies and services including digital cellular technologies (e.g. TDMA, E-TDMA, narrow band CDMA, and broadband CDMA), geopositioning services, one way and two-way paging services, packet data services, enhanced specialized mobile radio, personal computing services, two-way satellite systems, cellular digital packet data (CDPD) and others. Fragmenting forces within the wireless communication industry have been further enhanced by regulatory actions of the U.S. government. In particular, the U.S. government is preparing to auction off portions of the radio spectrum for use in providing personal communication services (PCS) in a large number of relatively small contiguous regions of the country. The U.S. government is also proposing to adopt regulations which will encourage wide latitude among successful bidders for the new radio spectrum to adopt innovative wireless technologies.
Until the market for wireless communication has experienced an extended "shake-out" period it is unlikely that a clear winner or group of winners will become apparent. Any portable unit which is capable of interacting with more than one service provider or radio infrastructure would obviously have advantages over a portable unit which is capable of accessing only a single service provider. Still better would be a portable unit which could be reprogrammed to interact with a variety of different service providers. Previous attempts to provide such multi modal units have produced a variety of interesting, but less than ideal, product and method concepts.
Among the known multi-modal proposals is a portable telephone, disclosed in U.S. Pat. No. 5,127,042 to Gillig et al., which is adapted to operate with either a conventional cordless base station or cellular base station. U.S. Pat. No. 5,179,360 to Suzuki discloses a cellular telephone which is capable of switching between either an analog mode of operation or a digital mode of operation. Yet another approach is disclosed in U.S. Pat. No. 4,985,904 to Ogawara directed to an improved method and apparatus for switching from a failed main radio communication system to a backup communication system. Still another proposal is disclosed in U.S. Pat. No. 5,122,795 directed to a paging receiver which is capable of scanning the frequencies of a plurality of radio common carriers to detect the broadcast of a paging message over one of the carriers serving a given geographic region. In U.S. Pat. No. 5,239,701 to Ishii there is disclosed a radio receiver which is responsive to an RF signal containing a plurality of channel frequencies, each having broadcast information, and a circuit for producing a wide band version of the received RF signal and a circuit for producing a narrow band version of the received RF signal.
While multi-modal in some regard, each of the technologies disclosed in the above listed patents is highly specialized and limited to a specific application. The systems disclosed are clearly non-adaptive and are incapable of being easily reconfigured to adapt to different transmission protocols or different radio infrastructures. Recently, Motorola has announced beta testing of a system called "MoNet" which will allegedly allow users to operate on whatever wireless network happens to be available using protocol and frequency agile radio modems. The MoNet technology will be integrated in both networks and mobile devices and will permit first time users to fill out an electronic application, transmit it, and receive a personal ID to allow the user to operate on any of several mobile networks yet receive just one bill. Another provider of an open system is Racotek of Minneapolis, Minn. which offers client server architecture designed to be portable across different mobile devices, host platforms, and radio infrastructures.
While the limited attempts to deal with the fragmentation of the wireless communication industry have had some merits, no one has yet disclosed a truly self adaptive, omni-modal wireless product which enables an end user to access conveniently various wireless services in accordance with a selection process which is sufficiently under the control of the end user.
SUMMARY OF THE INVENTION
A fundamental objective of the subject invention is to overcome the deficiencies of the prior art by providing a truly omni-modal wireless system and method which is adaptive to the selectively variable desires of the end user and is reconfigurable to allow maximum utilization of the total radio frequency spectrum assigned in any given geographic are for wireless communication.
Another more specific object of the subject invention in the provision of multiple portable product in the hands of plural individual users wherein each portable product would be capable of utilizing any one of the wireless data services within a given geographic area based on a user determined criteria such as: (1) the cost of sending a data message, (2) the quality of transmission link (signal strength, interference actual or potential), (3) the potential for being bumped off of the system (is service provider at near full capacity), (4) the security of transmission, (5) any special criteria which the user could variably program into his omni-modal wireless product based on the user's desires or (6) any one or more combinations of the above features that are preprogrammed, changed or overridden by the user.
Another object of the subject invention is to provide plural omni-modal wireless products which would allow for adaptive service provider selection based on user experience with specific service providers.
A more specific object of the subject invention is to provide plural omni-modal wireless products which would have the effect of inducing intense competition for customers among various wireless data service providers based on quality of service and price by allowing the user to easily and conveniently identify the service providers that best meet the user's performance requirements.
Another object of the invention is to provide a network of omni-modal wireless products and service providers which is designed to provide the most business and profit making potential to the service providers who best meet the varying demands of the greatest number of omni-modal wireless product users.
Still another objective of the subject invention is to promote and encourage introduction of innovative technology which will satisfy the desires of end users to receive the best possible quality wireless service at the lowest possible cost by promoting real time adaptive price and service competition among cell service providers.
Another objective of the subject invention is to allow wireless service providers to broadcast electronically as part of any "handshaking" procedure with a omni-modal wireless product information such as (1) rate information and (2) information regarding system operating characteristics such as percent of system capacity in use and/or likelihood of being dropped.
Still another objective of the subject invention is to create a user oriented source enrollment and billing service in the wireless data market by establishing uniform standard for "handshakes" to occur between cell service providers and omni-modal wireless products.
A more specific object of this invention is to provide a network of wireless service providers adapted to interact with a population of omni-modal wireless products within a given geographic area in a manner to permit the wireless service providers to "borrow" radio frequencies from other wireless service providers within the same geographic region. As a cellular service provider in a given region finds that one of its service areas or cells has become nearly or fully loaded, frequency could be borrowed from a competitor, such as a PCS provider serving the same region. Selected omni-modal wireless product users in the overloaded area would be told to switch their omni-modal to the "leased" frequency but to use the non-PCS communications protocol appropriate to the type of service desired by the user. Implementation of this method broadly within a given geographic region will have the effect of insuring that the available radio spectrum is used to its maximum capacity to serve the needs of the wireless users on a real time basis.
These objects, and others which will be apparent to those skilled in the art upon review of the specification, are achieved in the present invention by an omni-modal radio circuit implemented by a standard radio computing chip or chipset which can serve as a computer (special or general purpose), or as an interface to a general purpose personal computer. The chip preferably includes a modem and associated processing circuits. So that it can perform at least basic processing functions such as displaying data, accepting input, etc., the chip may also incorporate at least a basic microprocessor. The processor may provide only predetermined functions, accessible through a standard applications programming interface, or in more advanced designs the processor can run other software or firmware added by the product maker. Exemplary processor functions of the chip include radio network interface control (call placement, call answering), voice connection, data transmission, and data input/output. The chip can be used to implement a variety of omni-modal devices and can provde computing resources to operate fundamental communications programs.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 are block schematic diagrams of an omni-modal radio communications circuit according to the present invention;
FIG. 2 is a block schematic diagram of an advanced cellular telephone implemented using an omni-modal radio communications circuit according to the present invention;
FIG. 3 is a block schematic diagram of a personal communicator implemented using an omni-modal radio communications circuit according to the present invention;
FIG. 4A is a plan view of the front of a data transmission and display radiotelephone implemented using an omni-compatible radio communications circuit;
FIG. 4B is a plan view of the back of a data transmission and display radiotelephone implemented using an omni-compatible radio communications circuit;
FIG. 5 is a block schematic diagram of a telephone/pager implemented using the present omni-modal radio communications circuit;
FIG. 6A is a block schematic diagram of a dual mode cellular/cordless landline telephone implemented using the present omni-modal radio communications circuit;
FIG. 6B is a flowchart showing a method of operation of a dual mode cellular/cordless landline telephone according to the present invention;
FIG. 7 is a block schematic diagram of a personal computer incorporating an omni-modal radio communications circuit;
FIG. 8 is a block schematic diagram of a special purpose radio data transmitting device implemented using an omni-modal radio communications circuit;
FIG. 9 is a flowchart showing a radio system selection method by which information carriers are selected according to varying specified criteria;
FIG. 10 is a flowchart showing a method of broadcasting local carrier information to facilitate carrier selection by customers for a particular information transmission task;
FIG. 11 is a flowchart showing a handshake sequence for arranging information transmission using the omni-modal device of the present invention;
FIG. 12 is a plan view of a modular implementation of the omni-modal radio communications circuit of the present invention installed in a cellular telephone;
FIG. 13 is a plan view of a modular implementation of the omni-modal radio communications circuit of the present invention installed in a personal computer;
FIG. 14 is a block schematic diagram showing a system for relaying paging signals to the omni-modal device of the present invention using a cellular telephone system; and
FIG. 15 is a flowchart showing a method of relaying paging signals to the omni-modal device of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A preferred embodiment of a standardized radio processing circuit 1 is shown in FIGS. 1A and 1B. The standardized radio processing circuit 1, shown in FIGS. 1A and 1B taken together, may be implemented on a single VLSI chip or on a set of VLSI chips making up a chipset. As will be seen, this chip or chipset provides a standard building block which can be used to make a plurality of consumer products that provide data transmission capability. As will be seen later with reference to FIGS. 2 through 8, by adding minimal external components to the standardized circuit 1, a wide variety of products can be produced. Also, as will be seen, the standardized circuit 1 can be advantageously implemented on a removable card with a standardized interface connector or connectors, so that it can then be selectively inserted into and removed from a variety of devices to provide the devices with radio information transmission capability.
In terms of the preferred functional and operational characteristics of circuit 1, it is particularly significant that this circuit provides a multi-modal or omni-modal communications capability. That is, circuit 1 can be adjusted by the user, or automatically under stored program control, to transfer information over at least two different radio communications networks, and preferably all networks available in a particular area within the frequency range of the transceiver of circuit 1.
Examples of radio communications networks which circuit 1 may be designed to use include commercial paging networks; the U.S. cellular telephone network or Advanced Mobile Phone System (AMPS); alternative cellular telephone network standards such as the European standard; digitally modulated radiotelephone systems operating under various encoding techniques such as TDMA, CDMA, E-TDMA, and BCDMA; Cellular Digital Packet Data (CDPD); Enhanced Specialized Mobile Radio (ESMR); ARDIS; Personal Cellular Systems (PCS); RAM; global positioning systems; FM networks which transmit stock prices or other information on subcarriers; satellite-based networks; cordless landline telephones (such as 49 Mhz and particularly 900 Mhz systems); and wireless LAN systems. Preferably, circuit 1 is also designed to use the landline/public switched telephone network (PSTN).
As another feature, the omni-modal circuit 1 may perform local positioning calculations to accurately determine its location by monitoring precisely synchronized timing signals which may be broadcast by cell sites for this purpose. If such timing signals were provided, the omni-modal circuit 1 could receive the signals, determine the relative time delay in receiving at least three such signals from different transmitter locations, and triangulate to determine the distance of the omni-modal circuit to each of the transmitters. If the omni-modal circuit 1 is installed in a vehicle, this information may be used to determine the location of the vehicle.
As will be seen, for each system which can be accessed by circuit 1, appropriate cross connections are provided between the radio circuit or landline interface, as selected, and voice or data sources and destinations. The appropriate cross connections are established under program control and include conversions between digital and analog signal forms at appropriate points in cases where a signal in one form is to be transmitted using a method for which a different signal form is appropriate. The operating parameters of the transceiver may be optimized by a digital signal processor for either voice or data transmission.
In addition, a library of command, control and data transmission protocols appropriate for each supported system may be included in circuit 1, and the device can implement the correct protocols by consulting a lookup table during transmissions to obtain the data channel protocols appropriate to the system selected. In another embodiment, the library of command, control, and data transmission protocols may be replaced, or supplemented, by information transmitted over the radio frequencies to the device by the carrier, or information downloaded from a hardwired connection to another device. Flash memory, EEPROMs, or non-volatile RAM can be used to store program information, permitting replacement or updating of the operating instructions used by the device.
As examples, the library functions accessible by the device (and also by external devices which may call the library functions) may include the following: Select RF modulation frequency; select RF modulation protocol; select data formatting/conditioning protocol; transmit data in input stream using selected network and protocol; select output; select input; select data/voice mode; answer call; generate DTMF tones and transmit on selected network; scan for control channels/available systems; obtain cost information for current selected system; obtain cost information for all systems; obtain operating quality information for current system; obtain operating quality information for all systems; request transmission channel in system; obtain signal strength for current channel; obtain signal strength for all active systems; and initiate a transmission on the selected network.
FIG. 1A shows a block schematic diagram of a preferred embodiment of an omni-modal radio communication radio frequency (RF) circuit. In the example shown, the RF circuit includes antenna 2, diplexer 4, amplifier 6, transmit mixer 8, receiver mixer 10, programmable local oscillator 12, modulation selector switches 14 and 16, analog detector-demodulator 18, digital demodulator 20, analog modulator 22, digital modulator 24, voice grade channel output 26, digital output 28, voice grade channel input 30, and digital input 32.
Voice grade channel output 26 is connected to analog detector-demodulator 18 and digital output 28 is connected to digital demodulator 20. Analog detector-demodulator 18 and digital demodulator 20 are selectively connected to receiver mixer 10 through switch 14. Receiver mixer 10 is connected to both local oscillator 12 and diplexer 4. Diplexer 4 is connected to antenna 2. These components provide radio frequency receive circuitry that allows selective reception and demodulation of both analog and digitally modulated radio signals.
Voice grade channel input 30 is connected to analog modulator 22 and digital input 32 is connected to digital modulator 24. Analog modulator 22 and digital modulator 24 are selectively connected to transmit mixer 8 through switch 16. Transmit mixer 8 is connected to both local oscillator 12 and amplifier 6. Amplifier 6 is connected to diplexer 4 and diplexer 4 is connected to antenna 2. These components comprise radio frequency transmit circuitry for selective transmission of analog or digitally modulated radio signals.
The operation of the omni-modal radio communication RF circuit shown in FIG. 1A will now be described in more detail. Antenna 2 serves to both receive and transmit radio signals. Antenna 2 is of a design suitable for the frequency presently being received or transmitted by the RF circuit. In the preferred embodiment, antenna 2 may be an antenna suitable for receiving and transmitting in a broad range about 900 Mhz. However, different antennas may be provided to permit different transceiver ranges, including dipole, yagi, whip, micro-strip, slotted array, parabolic reflector, or horn antennas in appropriate cases.
Diplexer 4 allows antenna 2 to receive broadcast radio signals and to transmit the received signals to the demodulators 18 and 20, and to allow modulated radio signals from modulators 22 and 24 to be transmitted over antenna 2. Diplexer 4 is designed so that signals received from amplifier 6 will be propagated only to antenna 2, while signals received from antenna 2 will only be propagated to receiver mixer 10. Diplexer 4 thus prevents powerful signals from amplifier 6 from overloading and destroying receiver mixer 10 and demodulators 18 and 20.
The receive path of the omni-modal RF circuit comprises receiver mixer 10, which is connected to, and receives an input signal from, diplexer 4. Receiver mixer 10 also receives a reference frequency from local oscillator 12. Receiver mixer 10 converts the signal received from diplexer 4 to a lower frequency signal and outputs this intermediate frequency on output line 36 to switch 14. Switch 14 is connected through control line 38 to a microprocessor (not shown). Control line 38 selectively controls switch 14 to pass the intermediate frequency signal on output line 36 to either analog detector-demodulator 18 or to digital demodulator 20. This selection is controlled based upon the type of signal currently being received. For example, if the omni-modal circuit 1 is tuned to an analog communication system, switch 14 would be connected to analog detector demodulator 18. If, however, the omni-modal circuit 1 is receiving a digital modulated signal, switch 14 would be in a state to allow an intermediate frequency on output line 36 to be transmitted to digital demodulator 20.
Analog detector demodulator 18 receives analog signals through switch 14 from receiver mixer 10 on output line 36. Analog detector demodulator converts the RF modulated signal received as an intermediate frequency into a voice grade channel or VGC. The voice grade channel may comprise an audio frequency spectrum going from approximately 0 Hz to approximately 4 KHz. Analog detector demodulator 18 is designed for demodulation of analog radio frequency signals. For example, analog detector demodulator would be capable of demodulating a frequency modulated (FM) radio signals. Analog detector demodulator 18 may also be capable of demodulating amplitude modulated (AM) radio signals.
Digital demodulator 20 is designed to demodulate digital signals received from receiver mixer 10 through switch 14. Digital demodulator 20 is designed to demodulate digital signals such as, for example, pulse code modulation (PCM), time division multiple access (TDMA), code division multiple access (CDMA), extended time division multiple access (E-TDMA) and broad band code division multiple access (BCDMA) signals. The output 28 from digital demodulator 20 could consist of a digital bit stream.
The transmit circuitry of the omni-modal RF circuit will now be described in detail. Analog voice grade channel signals can be received over analog input 30 which is connected to analog modulator 22. Analog modulator 22 acts to modulate the received voice grade channel onto an intermediate frequency signal carrier. Analog modulator 22 would be capable of modulating frequency modulation (FM) or amplitude modulation (AM) signals, for example.
As can be seen in FIG. 1A, analog modulator 22 is connected to switch 16. The intermediate frequency output from analog modulator 22 on output line 42 is sent to switch 16. Switch 16 is connected to a microprocessor (not shown) in a manner similar to switch 14 described above. Switch 16 is capable of selectively connecting transmit mixer 8 to either analog modulator 22 or digital modulator 24. When switch 16 is connected to analog modulator 22 through output line 42, analog modulated signals are transmitted to transmit mixer 8.
Digital input can be received by the transmit portion of the RF modulator circuitry through digital input 32. Digital input 32 is connected to digital modulator 24 which acts to modulate the received digital data onto an intermediate frequency RF carrier. Digital modulator 24 may preferably be capable of modulating the signal into a PCM, TDMA, E-TDMA, CDMA and BCDMA format. The output 44 of digital modulator 24 is connected to switch 16. Switch 16 can be controlled through control line 40 to select the digital modulated signal on output 44 and to selectively transmit that signal to transmit mixer 8.
Transmit mixer 8 is connected to programmable local oscillator 12 which is capable of generating frequencies that cover the frequency spectrum of the desired communication systems. Transmit mixer 8 operates in a manner well known in the art to convert the intermediate frequency signal received from switch 16 to a radio frequency for transmission over a radio communication system. The output of transmit mixer 8 is connected to amplifier 6. Amplifier 6 acts to amplify the signal to insure adequate strength for the signal to be transmitted to the remote receiving station. Amplifier 6 may be connected to control circuitry to allow the power output of amplifier 6 to be varied in accordance with control signals received from the control circuitry. The output of amplifier 6 is connected to diplexer 4 and, as described above, to antenna 2.
FIG. 1B is a block schematic diagram of the input and control circuitry of omni-modal circuit 1. As can be seen from FIG. 1B, the input and control circuitry comprises speaker 100, microphone 102, voice processing circuitry 104, digital to analog converter 106, analog to digital converter 108, first selection switch 122, microprocessor 110, memory 112, data input 114, data output 116, data processing circuitry 118, second selector switch 120 and modem 124.
Microprocessor 110 is connected to memory 112 and operates to control the input circuitry as well as the programmable local oscillator 12 and switches 14 and 16 shown in FIG. 1A. Memory 112 can contain both data storage and program information for microprocessor 110. Microprocessor 110 may be any suitable microprocessor such as an Intel 80X86 or Motorola 680X0 processor. Memory 112 contains a program that allows microprocessor 110 to selectively operate the voice processing circuitry, data processing circuitry and switches to select the appropriate transmission channel for the communication signal currently being processed. In this manner, microprocessor 110 allows omni-modal circuit 1 to selectively operate on a plurality of radio communication systems.
As can be seen in FIG. 1B, an externally provided speaker 100 and microphone 102 are connected to voice processing circuitry 104. Voice processing circuitry 104 has output 142 and input 144. Voice processing output 142 is connected to switch 122. Similarly, voice processing input 144 is connected to switch 122. Switch 122, which may be an electronic analog switch, comprises two single pole double throw switches which operate in tandem to selectively connect voice output 142 and voice input 144 to appropriate data lines. Switch 122 is connected through control line 146 to microprocessor 110. Control line 146 allows microprocessor 110 to selectively operate switch 122 in response to commands received from the user or in response to a program in memory 112. In a first position, switch 122 connects voice processing input 144 to voice grade channel output 126. Referring to FIG. 1A, voice grade output 126 is connected to the output 26 of analog detector demodulator 18. In this manner, voice processing circuitry 104 is able to receive demodulated analog voice signals from analog detector demodulator 18. When voice processing input 144 is connected to 126, voice processing output 142 will be connected to voice input 130. As can be seen in FIG. 1A, voice input 130 is connected to voice grade channel input 30 of analog modulator 22. In this manner, voice processing circuitry 104 can transmit voice through the transmit circuitry of FIG. 1A.
If switch 122 is changed to its alternate state, voice processing input 144 will be connected to digital to analog converter 106. Digital to analog converter 106 is connected to digital input 128 which, referring to FIG. 1A, is connected to digital output 28 of digital demodulator 20. Digital to analog converter 106 acts to receive a digital information bit stream on digital input 128 and to convert it to an analog voice grade channel. The analog voice grade channel from digital to analog converter 106 is sent through voice input 144 to voice processing circuitry 104. Voice processing circuitry 104 can then amplify or alter the voice grade channel signal to the taste of the user and outputs the signal on speaker 100. Voice processing output 142 is connected to analog to digital converter 108 which in turn is connected to digital output 132. Digital output 132 is connected in FIG. 1A to digital input 32 and to digital modulator 24. In this manner, voice processing circuitry 104 is capable of transmitting a voice or other analog voice grade channel signal through a digital modulation system.
As noted above, omni-modal circuit 1 is capable of transmitting data over a plurality of radio frequency communication systems. As can be seen in FIG. 1B, data input 114 and data output 116 are connected to data processing circuitry 118. Data input 114 allows the processing circuitry to receive data from any number of user devices. The format of the data received on data input 114 may be variable or standardized depending on the circuitry provided in data processing circuitry 118. For example, data input 114 may use a standard RS-232 serial interface to receive data from a user device. Data input 114 may also use a parallel twisted pair or HPIB interface as well. Data output 116 similarly transmits data in a format compatible with the equipment being used by the user. Data processing circuitry 118 is connected to microprocessor 110 which acts to control the formatting and conditioning of the data done by data processing circuitry 118. For example, data processing circuitry 118 may add protocol information or error correction bits to the data being received on data input 114. Conversely, data processing circuitry 118 may act to remove overhead bits such as protocol or error correction bits from the data prior to its output on data output 116. Data processing circuitry 118 is connected to switch 120 through data output 150 and data input 152. Switch 120 operates in a manner similar to that described with respect to switch 122 above. Switch 120 is connected to microprocessor 110 through control line 148. Microprocessor 110 operates to control switch 120 to selectively connect the data output 150 to either digital circuit output 140 or to modem input 156. Switch 120 also operates to connect digital data input 152 to either digital input 138 or digital modem output 154. Modem 124 may be any standard modem used to modulate digital data onto an analog voice grade channel. For example, modem 124 may incorporate a modem chip set manufactured by Rockwell International Corporation that receives digital data and modulates it into a 4 KHz band width for transmission over standard telephone systems. Modem input 156 receives data from data processing circuitry 118 through data input 152 and switch 120. The data received over modem input 156 is modulated onto a voice grade channel and output on modulated modem output 136. Modulated modem output 136 is connected to voice grade channel input 30 of analog modulator 22 shown in FIG. 1A. Similarly, digital modem output 154 receives demodulated baseband signal from modem 124. The modulated data signal is received by modem 124 from modem input 134, which is connected to voice grade channel output 26 of analog detector demodulator 18. Modem 124 acts to demodulate the data received over modem input 134 and outputs a digital data stream on digital modem output 154. This digital data stream is connected through switch 120 and data input 152 to data processing circuitry 118. As described above, data processing circuitry 118 conditions and formats the data received from the modem and outputs the data to the user on data output 116. If the user has selected a digital RF transmission system, it is not necessary to use modem 124. In this case, switch 120 is operated so that the digital data output 150 from data processing circuitry 118 is connected through digital output 140. Digital output 140 is connected to digital input 32 of digital modulator 24 shown in FIG. 1A. Similarly, data input 152 to data processing circuitry 118 is connected through digital input 138 to digital output 28 of digital demodulator 20 shown in FIG. 1A.
As is readily apparent from the above discussion, FIGS. 1A and 1B together depict a radio frequency communication system that is capable of operating over a plurality of different radio channels and is further capable of transmitting either analog or digital data information signals as well as analog or digital voice signals. The system is also capable of transmitting a 4 Khz voice grade channel having both data and voice simultaneously present.
FIG. 1B broadly depicts the operation of the circuit which involves the selection by the microprocessor 110 of either a voice or data call. Once this selection is made, the data is then sent to the RF modulation circuitry shown in FIG. 1A. The RF modulation circuitry is capable of modulating or demodulating either analog or digital signals.
Circuit 1 is designed to facilitate product differentiation by companies making use of circuit 1 as a standard building block for radio voice and/or data communications devices. For example, each manufacturer may provide specialized interface features for the user, and specialized hardware controls appropriate for various user groups. Circuit 1 is particularly advantagous in facilitating these goals in that it provides microprocessor 110 and memory 112 that allow manufacturers to customize the operation of the circuit with little or no additional components. Furthermore, circuit 1 could be pre-programmed with a series of primitives that would allow a manufacturer to quickly and easily integrate the complex features of the device into a use friendly consumer product.
Referring next to FIG. 2, a block schematic diagram of an advanced cellular telephone implemented using an omni-modal radio communication circuit 1 shown in FIG. 1 is depicted. The omni-modal radio communication circuit of FIGS. 1A and 1B is shown in outline form as reference number 1. Also shown in FIG. 2 are speaker 100, microphone 102, digital data input 114, digital data output 116 and universal digital input/output interface 158. As can be seen from FIG. 2, the present radio communications circuit allows a cellular phone to be constructed with the addition of minimal components. The advanced cellular phone of FIG. 2 includes keypad 202, display 204 and interface connector 206. Keypad 202 and display 204 are connected to interface connector 206. Interface connector 206 connects with the universal digital input/output interface 158 which connects to the omni-modal radio communications circuit 1 depicted in more detail in FIGS. 1A and 1B. Keypad 202 may be any keypad used with telephone devices. Similarly, display 204 can be any display used with standard cellular telephones or other computing devices. For example, display 204 could be a light-emitting diode (LED) or a liquid crystal display (LCD) as commonly used with telephones, calculators and/or watches.
As shown in FIG. 2, keypad 202 and display 204 connect through interface connector 206 to universal digital input/output interface 158 of the omni-modal RF circuit. The universal digital input/output interface 158 allows the omni-modal circuit 1 to be connected with a variety of electronic devices including keypad 202 and display 204. It is contemplated that universal digital input/output interface 158 may comprise one connector or a plurality of connectors each having different data protocols transmitted and received therein. For example, universal input/output interface 158 may include a keyboard or keypad interface circuit as well as a display interface circuit. The keypad interface circuit would include necessary circuitry for buffering key strokes and receiving key input data from a keyboard. The display driver circuitry would include a memory and processor necessary for the display of data stored in the display memory. In this manner, the omni-modal circuit 1 is capable of interacting with many different keypads and display devices. In one preferred embodiment, the universal interface connector includes a serial addressable interface wherein the components connected to the serial interface have a unique address byte assigned to each component. This allows the serial interface to communicate with a plurality of devices sequentially. Keypad 202 for example may be assigned an address byte of 001, while display 204 would be assigned address byte of 002. When the universal interface desires to communicate from microprocessor 110 shown in FIG. 1B with the keypad or display, the appropriate address would be included in the data sent to the universal interface connector. Keypad 202 and display 204 would monitor the data coming across the universal interface 158 and would respond only to those bytes having an appropriate address corresponding to the selective device.
The advanced cellular phone of FIG. 2 includes digital data input 114 and digital data output 116. This allows the phone to transmit digital computer data without the need of bulky external interface devices. For example, it is often necessary to use a tip and ring interface emulator to communicate over a cellular network from a computer or other data source. With the present invention, however, it is only necessary to connect to the digital data input 114 and to the digital data output 116. The data protocol used on these may be any protocol suitable for data communication, but in the preferred embodiment would be a RS 232 serial interface. By connecting a computer serial interface port to data input 114 and data output 116, data may be transmitted using the omni-modal circuit 1. The microprocessor 110 and memory 112 shown in FIG. 1B would configure the internal circuitry of the omni-modal circuit for data transmission.
Also shown in FIG. 2 are speaker 100 and microphone 102. Speaker 100 and microphone 102 may be standard speakers and microphones used on cellular telephones and are adapted to allow the omni-modal circuit 1 to transmit voice communications over a cellular radio network.
FIG. 3 is a block schematic diagram of a personal communicator implemented through the use of the omni-modal circuit 1 shown in FIGS. 1A and 1B. As shown in FIG. 3, the personal communicator includes omni-modal circuit 1, personal communicator computing circuitry 302, telephone handset 318, and interface circuitry comprising data input 114, data output 116, and universal interface 158.
The personal communicator computing circuitry 302 includes display 304, microprocessor 306, memory 308, input device 316, data interface jack 310 and RJ-11 jack 312. As can be seen in FIG. 3, the microprocessor 306 is connected to the display 304, the memory 308, the input device 316 and to the data interface jack 310 and RJ-11 jack 312.
The personal communicator computing circuitry 302 acts to allow the user to interface and process data in a manner known to those of skill in the art. For example, display 304 may include an LCD display panel and may be color or black and white. Microprocessor 306 may include an Intel 80X86 microprocessor or any other microprocessor manufactured by Intel or Motorola or other computer processing chip manufacturers. Memory 308 includes random access memory (RAM) and read-only memory (ROM) necessary for the functioning of the computing device. Input device 316 may be a keyboard or a pen-based interface or other interface including voice recognition that allows for data to be input to the personal communicator computing circuitry 302. Microprocessor 306 is interfaced through data interface jack 310 to data input 114 and data output 116 of the omni-modal circuit. This allows the personal communicator computing circuitry 302 to transmit data using the omni-modal circuit 1. Also, as seen in FIG. 3, microprocessor 306 is connected through universal interface 158 to microprocessor 110 in the omni-modal circuit 1. This permits the microprocessors 306 and 110 to exchange control and operating information with each other. Should the microprocessor desire to make a data call, microprocessor 306 can instruct the microprocessor 110 shown in Figure 1B of the omni-modal circuit 1 to initiate a data call through a designated service provider. In response to such command from microprocessor 306, microprocessor 110 shown in FIG. 1B may initiate a switching action and configure the omni-modal circuit 1 to transmit data over a selected service provider. To increase the flexibility of the personal communicator computing device, an RJ-11 jack 312 is included. The RJ-11 jack is connected to the data lines from the microprocessor 306 and allows the personal communicator computing device to transmit data over a standard landline telephone.
In one particularly preferred embodiment of the invention, the omni-modal circuit 1 can transmit data over a landline telephone line using RJ-11 jack 312 and modem 124 shown in FIG. 1B. The microprocessor 306 of the personal communicator computing device would transmit data through data interface jack 310 and data input 114 to the omni-modal circuit 1. The omni-modal circuit 1, would receive the data at the data processing circuitry 118 and transmit the data through data output 150 and modem input 156 to modem 124 shown in FIG. 1B. Modem 124 would then modulate the data onto a voice grade channel and transmit the modulated data signal on modem output 154 through switch 120 and data input 152 to data processing circuitry 118. The data processing unit may then transmit the data over data output 116 and into microprocessor 306 through interface jack 310 shown in FIG. 3. The microprocessor 306 may then route the data through auxiliary data output line 314 to RJ-11 jack 312. In this manner, the personal communicator computing circuitry 302 is able to send data over standard landline telephone lines without the use of a second additional modem. The modem in the omni-modal circuit 1 serves two functions allowing the personal communicator user to send data through his standard landline wall jack or over a wireless network depending on the availability of each at the time the user desires to send the data.
Also shown in FIG. 3 is handset 318. In the preferred embodiment of the personal communicator, the speaker 100 and microphone 102 would be embodied in a separate handset 318. This handset 318 would connect to the omni-modal circuit 1 through an appropriate interface connection.
FIGS. 4A and 4B depict a communication device 402 employing the omni-modal circuit 1 of the present invention, and having an integrated display device for conveying information to a user. FIG. 4A shows the front of the communication device 402 that could serve as a cellular phone. The device 402 includes speaker 100, antenna 2, microphone 102 and key pad buttons 406. In this regard, the external features of the device are similar to those of a standard commercially available cellular phone. As shown in FIG. 4B, the device is unique in that it incorporates an expanded display 404 and control buttons 408, 410, 412 for the display of information to the user. For example, the display 404 could convey airline flight information to the user while they are connected with an airline representative. In response to a user request, the airline representative could transmit flight information to the user's communication device 402, which would then display this information on the display 404. The user could then cycle through the information using increment button 408 and decrement button 410. When the user desired to select a given flight, they could indicate assent by pressing the enter button 412. This information would then be transmitted digitally to the airline representative's computer.
The capabilities of the omni-modal circuit 1 facilitate its use in a device as shown in FIGS. 4A and 4B. Since the device is programmable through the use of microprocessor 110 and memory 112 (FIG. 1B), it is capable of switching between voice and data modes of operation. This allows the user to conduct a voice conversation and then to receive data for display on the integrated display device. Alternatively, the omni-modal circuit could access another communication service to receive data for display, or it might receive data over a subchannel during the conversation. This would be particularly advantageous if the user desired to continue a voice call while continuing to receive data information, as in the case of the airline flight selection example given above.
Referring next to FIG. 5, a block schematic diagram of a telephone/pager device using the omni-modal circuit 1 is shown. As can be seen from FIG. 5, the telephone/page device includes keypad 502, display 504 and control circuitry 506. The keypad 502 is connected to control circuitry 506. Display 504 is also connected to control circuitry 506. Control circuitry 506 is farther connected through universal digital input/output interface 158 to the microprocessor 110 of the omni-modal circuit shown in FIG. 1B.
The combination telephone/pager device shown in FIG. 5 is generally similar in design to the advanced cellular telephone shown in FIG. 2. One particularly advantageous aspect of the omni-modal circuit 1 is its ability to provide a great degree of flexibility in the design and implementation of communication circuits. For different implementations external to the omni-modal circuit, the memory 112 shown in FIG. 1B can be reprogrammed to provide different functions through microprocessor 110 for the universal digital interface 158.
In FIG. 5, the telephone/pager implementation includes control circuitry 506 which receives information through the universal digital interface 158 from microprocessor 110. The control circuitry can then determine whether or not a page signal has been received by the omni-modal circuit 1 and if so it can display the appropriate information on display 504. If, however, control circuitry 506 receives information from microprocessor 110 that a telephone call has been received or is being used, then control circuitry 506 can appropriately display the telephone information on display 504. Similarly, control circuitry 506 can receive information from keypad 502 and selectively process this information depending on the current mode of operation. For example, if the device shown in FIG. 5 is in pager mode, control circuitry 506 may allow keypad input to cycle through stored paging messages. If however, the device shown in FIG. 5 is in telephone mode, control circuitry 506 may process the keypad information received from keypad 502 as telephone commands and transmit control signals through interface 158 to microprocessor 110 to cause a telephone call to be placed. Further, control circuitry 506 can actuate alarm 508 which may be a audible alarm such as a beeping or a vibration generator. Alarm 508 serves to notify the user when a telephone call or page is received.
FIG. 6A is a block schematic diagram of a dual mode cellular/cordless landline telephone is disclosed. The dual mode device includes key pad 602, optional display 604, handset 606, and interface connector 608. The key pad 602 and optional display 604 are connected to microprocessor 110 (FIG. 1B) through interface connector 608 and universal digital interface 158.
Key pad 602 allows a user to provide information to microprocessor 110 for operating the dual mode device. For example, the user may operate the key pad to indicate that a certain call should be made on the cordless telephone network and not on the cellular network. To the contrary, the user may specify that the cellular network was to be used by operating the key pad 602 to so indicate.
One particularly preferred embodiment of a dual mode device may be programmed to allow for automatic selection of either a cellular communications network or a cordless telephone landline network. This is particularly advantageous in that a cordless telephone landline network is often considerably cheaper to access than is a cellular telephone network. Therefore, if the device will automatically access a cordless telephone network whenever one available, and use the cellular network only we absolutely necessary, the user can achieve substantial savings while still having a single, portable, communications unit that operates over a large geographic area. If the user requests service while within his home, for example, the cordless telephone system would be used and the user would be charged a minimal amount. If the user were to place a call while away from his home a greater charge would be incurred. The user, however, would use the same communications equipment regardless of where the service was used, and the service selection would appear transparent to the user.
FIG. 6B is a flowchart of one method that may be used to implement this embodiment. The process of FIG. 6B begins 650 by determining if the user has activated the device to request communications services 652. If the user has not requested communication services, the devices continues to check for a user request. If a user request is detected, the device then determines if it is within range of a cordless telephone landline system 654. If the device is within range of a cordless telephone landline system, then the device services the user's request using the cordless landline communication system 662 and the process terminates 664. If the device is not within range of a cordless landline network, then the device determines if it is within the service range of a cellular phone system 656. If the device is within range, the user's request is serviced using the cellular phone system 660 and the process terminates 664. If the device is not within range of a cellular system, then the device issues an alert to the user to indicate that no service is available 658 and the process terminates 664.
Although FIG. 6A and the above discussion focus on a dual mode cellular/cordless landline telephone, it should be understood that the a device in accordance with the present invention may include the ability to access additional communication systems. For example, it may be desirable to have a device substantially as shown in FIG. 6A, but having the ability to access a personal communication service (PCS) network in addition to the cellular and cordless landline systems. This would allow the user to achieve further cost savings while seamlessly moving throughout a given geographic area.
Referring next to FIG. 7, a block schematic diagram of a personal computer 702 incorporating an omni-modal circuit 1 is shown. As can be seen in FIG. 7, computer 702 includes antennae 2 and an interface port 704 that allows for a integrated circuit card to be inserted into the computer. As shown in FIG. 7, the interface port 704 has installed therein a removable card 701 comprising an omni-modal circuit 1. The omni-modal radio communications card 701 includes connector 706, which may include data input 114, data output 116 and universal digital interface 158 shown in FIG. 1B. This connector allows the omni-modal radio interface card 701 to communicate with the computer through a corresponding mating connector 708 inside the personal communicator. This allows the microprocessor 110 on the omni-modal radio communications card 701 to communicate with the memory and microprocessor contained in the computer 702. In a preferred embodiment, the omni-modal radio communications card 701 is in the form of a PCMCIA card adapted to interface into a standard slot in a portable or other computing device. FIG. 7 also shows an optional telephone handset 710 which may be interfaced to the radio communication interface card 701. Optional handset 710 includes speaker 100 and microphone 102, and serves to allow for voice communication over radio network service providers that provide such capability.
The omni-modal radio communication card 701 also has an external RJ-11 data jack 712. The external RJ-11 data jack 712 allows omni-modal communications card 701 to transmit data over a telephone landline circuit using a common RJ-11 interface cable. Omni-modal communications card 701 includes a modem 124 in FIG. 1B for modulating digital data onto a voice grade channel suitable for transmission over a landline telephone connection.
Therefore, the radio communications card 701 serves as a modem to the personal computer and a separate modem card or external modem is not necessary in order to transmit data over a landline jack. The microprocessor 110 in the omni-modal circuit card 701 allows the circuitry to select either landline transmission via external RJ-11 jack 712 or cellular radio transmission through antennae 2. This may be accomplished for example through an analog switch circuit as disclosed in U.S. Pat. No. 4,972,457, the disclosure of which is incorporated herein by reference.
FIG. 8 is a block schematic diagram of a special purpose radio data transmitting device 801 that is implemented using the omni-modal circuit. It is often desirable to be able to construct a device that will be capable of operating to send data wirelessly. For example, it may be desirable to include such a device in a vending machine or gasoline pump. Device 801 may then relay data at a predetermined time concerning the amount of consumables (e.g. food, beverages, gasoline, etc.) still remaining in stock. In this manner, it is not necessary to have a person physically inspect the device and evaluate the remaining stock, which would be considerably more expensive.
The omni-modal circuit 1 of the present invention can be used to implement a system as described above. Referring to FIG. 8, the omni-modal circuit 1 is connected to a data source 802 through data lines 806 comprising data input line 114 and data output line 116. Additionally, microprocessor 110 (FIG. 1B) is connected to the data source through universal digital interface 158 and control line 804. The resulting omni-modal device 801 can be programmed to access a selected communications service at a periodic interval and to transmit data from the data source at that time. This function can be included in the library of functions available on circuit 1. After accessing the communications service, microprocessor 110 may instruct data source 802 using control line 804 to transmit data over data lines 806. Of course, the omni-modal device 801 will have the circuits necessary to use a plurality of different transmission networks. However, because of mass production and the availability of predetermined designs it may be desirable to use the standard building block circuit 1 to implement limited-purpose devices which will be used with only one or two systems, even though these limited purpose devices will use only a portion of the built-in capabilities of circuit 1.
In addition to functions directly related to radio communications and modulation, the library may desirably include other functions which enable desirable computing features. For example, data displaying, electronic mail storage, retrieval, and composition, and other computing functions may be included in the library. In addition, if a high powered processor is provided, the library may be expanded to include substantial operating system functions so that circuit 1 can be used to construct full-fledged personal computers and personal communicators capable of running third party applications programs.
As described above, circuit 1 will be capable of utilizing any one of the wireless data services within a given geographic area. The selection of the service to be used can be made manually by the user, or can be selected automatically. Referring to FIG. 9, circuit 1 may have a preprogrammed routine for selecting information carriers based on varying criteria. As shown in FIG. 9, the criteria for selecting a carrier may be varied by the user. Possible criteria include the cost of sending a data message; quality of transmission link (signal strength, interference actual or potential); available bandwidth on a carrier for data transmission (or transmission speed supported); potential for being bumped off the system or having transmissions delayed (that is, is the service provider at nearly full capacity); security of transmission; or other special criteria which the user or the device may establish based on the user's individual priorities. As another example, the length of a data message to be transmitted may be considered as a factor in selecting the carrier. If the length of the proposed message is made known to circuit 1, this information can be used in conjunction with pricing information to determine the lowest cost route. For example, for very short messages a paging service or cellular digital packet data (CDPD) service might be selected. For longer messages, such as fax or data file transmission, a circuit switched connection with high speed data transfer capacity (such as AMPS cellular) may be more cost-effective.
Information about the costs and services offered by carriers in the area will be made available to the omni-modal circuit 1 for use in this competitive selection process, either through pre-programming by the user or selling organization or by transmission of the information in a manner described elsewhere herein.
The carrier may be selected by any one of the characteristics of the available competing carriers. For example, a given user may be price sensitive, and wish to always employ the lowest cost transmission method. Another user may have time-critical communications needs (e.g. securities trading or news reporting) and may prefer the most reliable or the highest speed transfer regardless of price.
In determining the cost of a particular transmission, circuit 1 preferably first determines the type and quantity of data to be transmitted. For example, if the user has selected a function of transmitting a file or an electronic mail message, circuit 1 will determine the length of the message, and file. This information is then used in determining the projected cost of transmitting the data on each system. For example, for a short E-mail message, the expected cost for an AMPS cellular system will be the cost of making a one-minute call. For a packet radio system, the expected cost will be the length of the message divided by the number of characters per packet, times the cost per packet. As long as the basis for carrier charges is provided to circuit 1, the cost factors relevant for any particular message can be calculated. Thus, circuit 1 can intelligently predict relative costs of transmitting over various networks and can operate with a low-cost preference dependent on characteristics of an individual message. Different low-cost transmission modes are appropriately selected for messages having different characteristics.
A more sophisticated approach than pure low-cost selection allows the user to assign weights to different competitive factors (price, signal clarity, transmission speed or other factors) depending on the individual preferences and needs of the user. Based on the assigned weights, the circuit then calculates a "score" for each available system and selects the system with the highest score. As an example, a user may instruct the circuit to select carriers based 60% on the ratio of the lowest price to the price of the particular carrier and 40% on normalized signal strength. If the cost to send the message on System I is $0.50 (signal strength 2), the cost on System II is $0.60 (signal strength 4), the cost on System III is $0.85 (signal strength 5) and the cost on System IV is $0.50 (signal strength 1) circuit 1 would calculate scores of:
System I: 0.60(0.50/0.50)+0.40(2/5)=0.76
System II: 0.60(0.50/0.60)+0.40(4/5)=0.82
System III: 0.60(0.50/0.85)+0.40(5/5)=0.75
System IV: 0.60(0.50/0.50)+0.40(1/5)=0.68
so System II would be selected. With the same systems available, if the user preferred a selection based 80% on cost and only 20% on signal quality, the scores would be
System I: 0.80(0.50/0.50)+0.20(2/5)=0.88
System II: 0.80(0.50/0.60)+0.20(4/5)=0.83
System III: 0.80(0.50/0.85)+0.20(5/5)=0.67
System IV: 0.80(0.50/0.50)+0.20 (1/5)=0.84
and System I would be selected. Of course, the application of this weighted selection criteria is not limited to, and is not necessarily based on, price and signal strength. Any number of criteria, including these or others, can be considered in a formula to meet the individual user's needs. The criteria for a particular user are stored in a user profile in the memory of circuit 1. Preferably, a default user profile corresponding to the preferences of a large number of users is established. Then, the individual user can change his or her user profile to establish different selection parameters and preferences at any time through appropriate input to circuit 1.
Particularly desirable selection algorithms may also take multiple factors into account by employing branching algorithms to select the carrier. For example, one multistage selection process based on multiple criteria would operate as follows. Initially, systems which are incapable of performing the desired function would be eliminated from consideration. For example, if the user wants to place a voice call, data-only systems would not be considered. As another example, if the user wants to send a fax to a customer and a given network has no capability of transmitting fax information to a specified telephone number, that system would not be considered for the proposed task. Next, among the systems available, circuit 1 may predict the lowest cost route based on a formula accounting for the message length and the costs of the available systems, including consideration of any long-distance surcharges implied by the destination of the information transfer. Finally, users may also prefer that circuit 1 automatically avoid selecting carriers which are suffering performance degradations because of capacity limits, or which have a particularly weak signal at the location of the user. In this way, if the carrier which would otherwise be preferred will not be able to provide a fast, accurate information transfer at the time from the user's location, the carrier that is the "next best" according to the primary programmed selection criteria (cost in this example) may be automatically selected. A tradeoff between signal quality and cost may also be arbitrated by the weighting method described above.
Preferably, any one or combination of the above selection criteria is available in the circuit 1 and the selection criteria can be selected, programmed, changed or overridden by the user. Adaptive service provider selection may be implemented based on user experience. That is, the information transmission track record of circuit 1 with a particular service provider (e.g. error rate, dropped connections, transmission time) can be stored and updated, and this information can be used as a weighted factor in selecting service providers. In this way, service providers providing poor services can be avoided in cases where more desirable alternatives are available.
The market and consumer implications of the present invention are substantial, in that the circuits and methods of the present invention tend to introduce intense competition for customers among various wireless carriers. The present invention automatically identifies service providers that best meet the user's performance requirements. In this way, service providers that meet the varying demands of the most user will have a large market share and maintain full usage of their available frequency spectrum. The invention therefore allows the users to drive the market by creating price and service competition among carriers.
In addition, the omni-modal capability of the present invention facilitates a free market for the use of frequency spectrum. Circuit 1 can be activated to select a specified channel frequency, but may be activated to use command, control, and data protocols on that channel that are normally appropriate for different channels, if the carrier controlling the frequency has authorized another carrier to temporarily use the first carrier's channel. As an example, a local AMPS cellular telephone carrier may have open channels, which may be temporarily "rented" to a Specialized Mobile Radio (SMR) carrier which is experiencing heavy traffic on its assigned channels. The SMR carrier may then direct persons requesting SMR service to operate on the "rented" channel, but using SMR protocols rather than the AMPS protocols which would normally be appropriate to that channel. This method of operation maximizes the efficient use of available frequencies by allowing carriers to shrink and expand the number of channels available based on current demand. During rush hours, when AMPS traffic is high, additional channels might be reallocated to AMPS by market forces; that is, the AMPS carrier will rent additional channels from under-utilized carriers to provide the services desired by the public at that time. At other times, demand for other systems may increase, and AMPS or other carriers may rent their under-utilized bandwidth to carriers having a substantial demand. This might occur, for example, if a network providing status reporting services from remotely located equipment (vending machines, gas pumps, etc.) is designed to transmit a large volume of data during late night or early morning hours. If the remotely located equipment is provided with an omni-tunable device, the status report network can rent channels from other carriers and use multiple channels to service its customers. In this way, economic incentives are established to ensure that airwave channels are assigned to their most productive use at all times, and the anti-competitive effects of carrier monopolies established by FCC channel assignments are reduced.
Referring to FIG. 9, one method for evaluating system selection is shown. The process begins 902 with the determination by the omni-modal circuit 1 of whether a data of voice service is desired 904. If a data service is desired, the circuit 1 obtains price information 908 for the available data service providers. If a voice service is desired, the circuit 1 obtains voice pricing information 906. Once this pricing information is obtained, the circuit 1 evaluates the information to make a service provider selection based on the criteria supplied from the user. Once this selection is made, circuit 1 is configured for accessing the selected service provider 912 and establishes a connection with that provider 914. Once the user has completed his use of the selected service provider, the process ends 916.
FIG. 10 is a flowchart showing steps useful in a method according to the present invention for "advertising" available carrier services in a geographic area. In this method, wireless service providers broadcast electronically, as part of any "handshaking" procedure with an omni-modal product, information such as rate information, information specifying system operating characteristics such as system utilization, the likelihood of being dropped, and other factors noted above which may be desirably considered in carrier selection. This information may be broadcast in each geographical region by a jointly operated or government-operated transmitter operating at a predetermined frequency. Circuit 1 may then be operated to scan the predetermined "service advertising" channel and obtain necessary information for use in selecting carriers. On a government-operated channel, government-collected statistics on the operation of the various carriers in the area may be transmitted as a consumer service to further encourage service competition and assist users in selecting the most appropriate carrier.
Alternatively, individual carriers may broadcast pricing information on individual command channels. Pricing can be changed on a dynamic basis to maintain a desired system load level. In fact, in one preferred embodiment, an automated price negotiation can be performed in which the circuit 1 transmits an indication of the type and amount of information which is to be transmitted, and the carrier responds by quoting a price for the transmission. Such quotes can be obtained from multiple carriers and the lowest cost transmission mode can be selected, or the quoted prices can be factored into an equation that considers other factors in addition to price, as disclosed previously. As part of this scheme, radio carriers may implement a dynamic demand curve evaluation program in which system load and profitability are constantly monitored. The evaluation program may also monitor the percentage of requested quotes which are not accepted. In this way, the radio carrier's system can dynamically adjust prices to maximize revenue to the carrier at all times, based on a real-time model of the current demand curve for airtime service in the area.
One method in which system information could be distributed to users is shown in FIG. 10. The process starts 1002 by contacting a selected service provider 1004. The service provider provides information to a central location as discussed above. Once the information for the first selected service provider is complete, the process determines if other service providers exist 1008. If other providers exist, the process 1004 and 1006 is repeated for each additional service provider. When service information is compiled for all service providers, the process compiles and formats the information into a standard reporting form the is understandable to all mobile units 1010. The process then determines the proper modulating frequency and protocol for the desired geographic area 1012 and broadcasts this information to all mobile users on the selected frequency and using the selected protocol 1014. Once the information has been broadcast to the users, the process ends 1016.
Referring next to FIG. 11, a flowchart showing a handshake sequence for arranging information transmission using the omni-modal circuit 1 of the present invention is shown. The process begins 1102 with the omni-modal circuit 1 accessing a service provider 1104 and receiving carrier cost information from the service provider 1106. The omni-modal circuit 1 may also receive additional information from the service provider such as signal quality, system resources, and available bandwidth. The circuit 1 then stores the information received from the service provider 1108. The circuit determines if other service providers exist 1110 and, if they do, repeats the above steps to acquire cost and availability information for each service within the omni-modal circuit's range.
Once information has been acquired for all available service providers, the information is evaluated 1112. This evaluation could consist of a simple determination based on a single factor, or could include more complex calculations relating to weighting of given factors and qualities. The results of the evaluation are used to select a service provider to process the users pending request for services. A connection is established 1114 on the selected service provider, and the user's request is processed, after which the process ends 1116.
FIG. 12 is a view of a cellular radiotelephone 1200 which is generally of the type and configuration described above with reference to FIG. 2. However, radiotelephone 1200 is constructed using a modular omni-modal circuit 1 constructed on a removable card 1204 which is provided with a standardized connector or connector (for example, a PCMCIA connector) 1205 to establish all necessary interface connections to a plurality of receiving devices in the manner described above with reference to FIG. 7.
As can be seen in FIG. 12, a telephone shell 1202 containing a battery power supply, microphone, speaker, keypad, and antenna 2 has a receiving slot 1206 for receiving card 1204 carrying circuit 1. When card 1204 is installed in telephone shell 1202, connector 1205 mates with connector 1208 within slot 1206 and the external components of the shell 1202 are operatively combined with card 1204 to create a functional multi-modal cellular telephone.
FIG. 13 illustrates the installation of the same card 1204 in a notebook sized computer 1302, whereby the computer 1302 is provided with complete omni-modal network access. By using the same card 1204 containing standardized circuit 1 to provide radio network access for various devices, the user can avoid maintaining multiple accounts or telephone numbers, yet can communicate by radio using many devices. For example, a receiving slot for card 1204 could be provided in the user's automobile, and insertion of card 1204 upon entering the car would activate cellular communications capability in the car. The same card 1204 can be readily transferred between the car, a portable handset shell as shown in FIG. 12, and a computer as shown in FIG. 13 for data transmission.
The omni-modal circuit of the present invention can perform both page receiving and other functions, such as placing cellular telephone calls. However, since only a single transmitting and receiving circuit is provided, when the device is in use on a non-paging communications network such as an AMPS cellular telephone system, any pages directed to the device may not be received. The present invention provides a solution to this potential problem in which the paging system control is interconnected with other network(s) such as the local AMPS cellular system. It should be understood that while connection of the pager system to the AMPS system is shown as an example, such connections may be provided between any systems used by the omni-modal circuit 1 to achieve similar objectives.
FIG. 14 is a block schematic diagram of a paging relay system according to the present invention for use with omni-modal circuits 1 that support pager functions and also a non-pager network function such as cellular telephone operation. FIG. 14 shows a paging system 1400 which is connected in a conventional manner by lines 1406 to a broadcast antenna 1408 which transmits pager signals to pager devices such as the omni-modal circuit 1 shown in the Figure. In addition, FIG. 14 shows a cellular telephone network office 1402 which is connected to control the operation of the cellular telephone cell site transmitter 1412 by lines 1410.
Significantly, the paging system 1400 is connected to the cellular telephone network office 1402 by lines 1404 which permit transfer of operational and control information between the paging system 1400 and cellular telephone network office 1402. Because of the connection of lines 1404, the paging system can determine whether the omni-modal device 1 is engaged in a cellular call and will thus be unable to receive a page.
FIG. 15 is a flowchart showing a preferred operation of the pager and other (for example AMPS) systems interconnected as described with reference to FIG. 14. In block 1502, the pager system first determines by reference to stored records whether the pager device which is to be contacted is an omni-modal circuit 1 which may be engaged in data transmission with another system at the time of any given page. If not, the page can be sent by the usual broadcast method in block 1504. If an omni-modal circuit 1 is involved in the paging operation, the pager system then contacts any connected networks which might be in use by omni-modal device 1 and inquires whether the device is in fact using such networks in block 1506. If not, the omni-modal device is presumed to be available for receiving a page and control transfers to block 1504 for transmission of the page by conventional methods. If circuit 1 is in use, the pager system determines whether delivery by the alternate network may be accomplished in block 1508. This may be determined by appropriate factors, including whether the network (e.g. AMPS) is capable of and willing to deliver the page information to circuit 1, and whether the user of circuit 1 has subscribed to this service.
If delivery by the alternate network is not available, control transfers to block 1510 which imposes a time delay. The page information is stored, and after some appropriate period of time, control transfers to block 1506 and the pager system again attempts to determine whether the page can be transmitted by conventional means.
If the alternative network is able to deliver the page and this service is to be provided, control transfers from block 1508 to block 1512 and the page is transmitted over the alternative system. In the case of the AMPS system, the page information may be transmitted as a momentary interruption in an ongoing conversation, as information provided on a command channel, as subaudible information (e.g. in a band from 0 to 300 Hz), or by another appropriate method. | A network and method of operating a network of wireless service providers adapted to interact with a plurality of omni-modal wireless products within a given geographic area in a manner to permit the wireless service providers to "borrow" radio frequencies from other wireless service providers within the same geographic region. As a cellular service provider in a given region finds that one of its service areas or cells has become nearly or fully loaded, frequency could be borrowed from a competitor, such as a PCS provider serving the same region. Selected omni-modal wireless product users in the overloaded area would be told to switch their omni-modal to the "leased" frequency but to use the non-PCS communications protocol appropriate to the type of service desired by the user. Implementation of this method broadly within a given geographic region will have the effect of insuring that the available radio spectrum is used to its maximum capacity to serve the needs of the wireless users on a real time basis. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation application of U.S. patent application Ser. No. 11/365,323 (now U.S. Pat. No. 7,905,451), filed Mar. 1, 2006, which claims the benefit of U.S. Provisional Patent Application No. 60/658,125, filed Mar. 3, 2005, and of German Patent Application No. 10 2005 009 750.2, filed Mar. 3, 2005, the disclosures of which applications are each hereby incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to an arrangement. In particular, the present invention relates to an arrangement of a first furnishing and a second furnishing, as well as a means of transportation.
In commercial transports, in particular means of transportation, providing passengers with sufficient comfort in the transport is often a concern. Sufficient comfort for the passengers means a sufficiently large space offered which may be occupied by the passengers.
A generous and roomy design of an interior makes an especially pleasant impression on the passengers. A compromise must often be made, since every available space and/or any arbitrary surface may not be used for placing passenger seats or making an occupancy area for passengers. Thus, for example, emergency exits must be kept free and may not be considered in the planning, for positioning passenger seats, for example. In addition, extensive safety and supply devices must be placed, because of which further space is not available.
There are furnishings, such as flight attendant seats, which must only be used during the takeoff and landing phases of an aircraft.
A flight attendant folding chair arrangement, which is attached to the wall of an aircraft cabin using multiple individual holders, is known from the patent specification U.S. Pat. No. 4,460,215. Moreover, a cabin attendant seat of thin profile, which folds together automatically when the occupant stands up, is known from patent specification U.S. Pat. No. 3,594,037.
SUMMARY OF THE INVENTION
Amongst other things, it may be an object of the present invention to provide a space-saving arrangement of furnishings.
This object maybe achieved by an arrangement of a first and a second furnishing and by a means of transportation having a corresponding arrangement having the features according to the independent claims.
According to an exemplary embodiment of the present invention, an arrangement of a first and a second furnishing is provided, wherein at least one part of the first furnishing being movable in the direction of the second furnishing, and wherein at least one part of the second furnishing being movable to free a space to receive the at least one part of the first furnishing.
According to another exemplary embodiment of the present invention, a means of transportation having an arrangement comprising the features described above is provided.
It may happen that in partitioned spaces, only limited space is available because of the spatial delimitation. In spite of this, it may be necessary to house different furnishings on this limited available space or room. Furnishings may, for example, be monuments, interior furnishing components, seats, particularly passenger seats, a partition wall, a safety or supply unit, or other furnishings for the aircraft interior.
It may be that a first furnishing is to be movable. Due to the movement, a space or room requirement for the first furnishing may be greater than for a corresponding statically attached first furnishing. The additional room requirement arises because of the deflection which is caused by the movement of at least one part of the first furnishing.
For example, a first furnishing may be seat, particularly a passenger seat. A seat may have a seat surface and a backrest. For a seat, particularly a reclining seat, the seat may have two operating position or modes of operation. A first operating position may be a seated position having an upright backrest, while a second operating position may be a rest position. The rest position may make it possible for the user to assume a reclining position on the seat in a relaxed posture. In this case, the backrest may be folded down to recline. An additional clearance zone may be necessary for the movement of the backrest.
An additional clearance zone may be necessary if a second furnishing is positioned so close to the seat that in the second operating position, the seat, in particular the rest, and the second furnishing do not obstruct one another. Upon a deflection of the seat in the direction of the second furnishing, the proximal arrangement of the second furnishing may obstruct the deflection of the rest.
The space or clearance zone required for the movement, inclination, or deflection of the backrest may result from the dimensions of the seat. For example, at a height of the backrest of approximately 1100 mm, a space of approximately 150 to 230 mm may be necessary.
However, the required clearance zone may be occupied by the second furnishing, for example. The second furnishing may be a partition wall or a flight attendant seat or another monument and/or furnishing element, for example. However, it may be that the second furnishing claims a space and/or clearance zone which would be required for the movement, particularly the pivot and/or inclination movement of a backrest. It may be, however, that the second furnishing must be installed in this obstructing position in order not to block exits, particularly emergency exits and/or areas or surfaces to be kept free.
If the first furnishing, particularly the seat rest, moves toward the second furnishing, such as a flight attendant seat or a partition wall having a flight attendant seat, at least a part of the second furnishing may be movable to free a space for receiving the first furnishing, particularly a part of the first furnishing. In other words, this means that, for example, the second furnishing frees a space which the first furnishing requires. The space or room may be any arbitrary spatial volume perpendicular to the base of the second furnishing in this case.
The space and/or room may be a partial space or three-dimensional partial volume of the room required by the second furnishing. This room may be positioned perpendicular to the base of the second furnishing. The first furnishing and/or a part of the first furnishing may penetrate into this new, freed clearance zone after the space is freed by the second furnishing.
Therefore, a chronological use of the first and second furnishings may be taken into consideration. In this case, time is mapped to a use of the different modes of operation. The two modes of operations of the seats may not occur simultaneously.
For example, the first furnishing may be a flight attendant seat and the second furnishing may be a passenger seat having an at least partially foldable back part and/or a backrest. Particularly in an aircraft and/or in an internal area of an aircraft fuselage, there may be different uses of the flight attendant seat and/or passenger seat at different times. During takeoff and landing, the backrest of the passenger seat should be placed upright. This may be a first mode of operation, for example. During takeoff and landing, the cabin personnel take their places on the flight attendant seats. A flight attendant seat may have a back area, in particular a partition wall, which projects into a spatial area of the aircraft interior.
During the flight, it may occur that the flight attendant seats are not used. The flight attendants normally pursue their activities during the flight. Therefore, their flight attendant seats remain free. During the flight phase, the passengers may be allowed to adjust the backrests of their seats. In particular, an inclination of the backrest may be desired for a rest and/or sleep phase. If the flight attendant seat and the passenger seat are close together, the inclination of the backrest may be obstructed by the space claimed by the flight attendant seat.
However, if the unused flight attendant seat, particularly the partition wall, also particularly a part thereof, may be moved out of the obstructing spatial area, an inclination, particularly a further inclination of the backrest of the passenger seat is possible. The passenger seat may thus be operated in a second mode of operation.
The second furnishing, particularly the flight attendant seat, does therefore not obstruct the first furnishing, particularly the passenger seat having its movable components, such as the movable backrest. Therefore, minimum dimensions of areas, such as occupancy area or entry/exit areas, may be maintained, although any arbitrary area may not be used.
According to a further exemplary embodiment of the present invention, the second furnishing is implemented to free the space automatically. The obstructing part of the second furnishing may thus be automatically removed from the interfering area. For the automatic release, the second furnishing may have a device which recognizes nonuse of the second furnishing, for example, and therefore automatically frees the space occupied by the second furnishing. However, the automatic mechanism may also be triggered by a user.
For example, the second furnishing may have a flap which is folded down by the weight of a user. If the weight of a user falls away, the flap may fold away automatically and cause a movement of at least a part of the second furnishing. However, an automatic mechanism may also be a trigger device, for example, particularly a button or a lever, after whose actuation the movement of the part of the second furnishing is triggered.
Through an automatic mechanism, no additional force or only a slight additional force may be necessary for removing the at least one part of the second furnishing from the obstructing area. The operation of the second furnishing is thus simplified. For example, the automatic release may also be performed using electromechanical converters.
According to a further exemplary embodiment of the present invention, a movement of the at least one part of the second furnishing is coupled to a movement of the at least one part of the first furnishing.
A connection between the movement of the first furnishing and the movement of the second furnishing may thus be produced. The second furnishing may thus provide the required clearance zone for the first furnishing when the second furnishing requires this clearance zone for its movement. It may be a mechanical or an electrical coupling, for example.
The coupled movement between the first and second furnishings does not have to be executed uniformly and/or congruently. This means that a backward movement of the at least one part of the first furnishing may result in a forward movement i.e., in opposite direction, of the at least one part of the second furnishing. In addition, a rapid movement of a part of the first furnishing may also result in a slow movement of a part of the second furnishing and vice versa. For example, joints, gears, or gear wheels may be used in any arbitrary combination to reshape the movement.
According to further exemplary embodiments of the present invention, the second furnishing may be a passenger secondary seat, a partition wall, and particularly a partition wall which has a further furnishing. For example, a further furnishing on the partition wall may in turn be a passenger seat. This means a flight attendant seat may be integrated into a partition wall. A partition wall may be used for the spatial partitioning of an area. It may also be used as an information platform, however. Information such as posters or electronic data may be displayed on the partition wall. A draft for passengers may also be avoided using a partition wall, however. A partition wall may also be used for sound insulation.
According to a further exemplary embodiment of the present invention, the second furnishing may have at least one pivot device, such as a joint, for pivoting the at least one part of the second furnishing. The joint may be positioned between parts of the second furnishing. It may thus be made possible for only a partial area of the second furnishing to be pivoted if additional space is claimed. A joint may allow the second furnishing, particularly a part thereof, to be permanently connected to a floor, particularly an aircraft floor, while a partial area of the second furnishing is movable and may free a space.
According to a further exemplary embodiment of the present invention, the second furnishing has a displacement device, such as a friction bearing, for displacing the at least one part of the second furnishing. The second furnishing may completely free the spatial area required of it. Using a slide rail, it may be possible for a furnishing, particularly a partition wall, to be displaced into a free area at a time in which it is not required. The area into which the second furnishing is displaced may be free, since it is not required or used at the time in which the space claimed by the second furnishing is required.
According to a further exemplary embodiment of the present invention, the displacement device is a seat rail. Particularly in an aircraft in which monuments and/or furnishings may be mounted on seat rails, the furnishing may comprise a displacement device or a friction bearing which fits on a seat rail. The mounting of the second furnishing may thus be simplified.
According to a further exemplary embodiment of the present invention, an arrangement is specified in which the second furnishing has an elastic element for pivoting the at least one part of the second furnishing. The elastic element may be positioned between parts of the second furnishing.
The elastic element may be a rubber element or a spring element, for example, so that a part of the second furnishing which has an elastic element may be slightly inclined, tilted, or displaced. A deflection of the part of the second furnishing may thus occur. This deflection may occur against the return force of the elastic element. Due to the return force of the elastic element, the part of the second furnishing is moved back into its starting position when the part of the second furnishing is released.
A displacement device, a pivot device, a joint, a friction bearing, or an elastic element may be easily retrofitted in an existing furnishing. By exerting pressure or coupling on the at least one part of the first furnishing, a movement of the at least one part of the second furnishing may occur. This movement may be an inclination or a linear movement, for example.
In particular, an aircraft cabin which is already existing and/or equipped with conventional passenger seats or an aircraft interior may be provided with the arrangement according to the present invention.
According to a further exemplary embodiment of the present invention, an arrangement is specified in which the second furnishing has at least one upper part and at least one lower part. The at least one upper part of the second furnishing may be lowered into the at least one lower part of the second furnishing. The upper part is further from the attachment, such as a floor surface, than the lower part. By lowering the at least one upper part into the at least one lower part of the furnishing, a spatial area above the lower part of the second furnishing may be freed. The height, particularly the length, of the second furnishing may thus be reduced telescopically. The space thus obtained may be used for a part of the first furnishing, particularly for the movement of a part of the first furnishing.
According to a further exemplary embodiment of the present invention, a means of transportation is specified in which the second furnishing is positioned in front of the exit and/or in an exit area of the means of transportation. In particular, a means of transportation is specified in which the second furnishing is positioned between a seat and an exit of the means of transportation.
In a means of transportation, it may be necessary to keep an exit free, particularly an exit door or an entry or exit area, during a specific time, such as the entry or exit time. The area kept free may be unused during a usage time of the means of transportation, for example. The at least one part of the second furnishing may use the exit area to free the space, if the second furnishing is positioned in front of the exit area. For this purpose, the at least one movable part of the second furnishing may be displaced or deflected into the exit area in a time in which the exit area is not used.
Through this displacement of the at least one part of the second furnishing, a movement of the at least one part of the first furnishing in the direction of the second furnishing may be made possible. This may be particularly advantageous if the means of transportation is an aircraft. In an aircraft, flight attendants may use the flight attendant seats attached in the exit areas of the aircraft. The time in which the flight attendants use the flight attendant seats is the takeoff time and/or the landing time, i.e., the time during takeoff and landing. During the flight, the flight attendant seats are normally not used. They may be displaced and/or inclined into an area of the exit during this time. Additional space for seats, particularly passenger seats may thus be provided.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following, exemplary embodiments of the present invention are described with reference to the figures, in which:
FIG. 1 shows an arrangement of a first and a second furnishing according to an exemplary embodiment of the present invention.
FIG. 2 shows a flight attendant seat and a passenger seat in a first mode of operation according to an exemplary embodiment of the present invention.
FIG. 3 shows a flight attendant seat and a passenger seat in a second mode of operation according to an exemplary embodiment of the present invention.
FIG. 4 shows a further arrangement of a flight attendant seat and a passenger seat in a first mode of operation according to an exemplary embodiment of the present invention.
FIG. 5 shows a further arrangement of a flight attendant seat and a passenger seat in a second mode of operation according to an exemplary embodiment of the present invention.
FIG. 6 shows a top view of the interior of an aircraft having an arrangement according to an exemplary embodiment of the present invention.
FIG. 7 shows a detail of an aircraft interior having an arrangement according to an exemplary embodiment of the present invention.
The illustrations in the figures are schematic and are not to scale. In the following description of FIG. 1 through FIG. 7 , identical reference numbers are used for identical or corresponding elements.
DETAILED DESCRIPTION
FIG. 1 shows the arrangement of a first furnishing 8 and a second furnishing 2 . The first furnishing 8 is a passenger seat 8 and the second furnishing 2 is a flight attendant seat 2 . The flight attendant seat 2 has a partition wall 4 and a seat surface 6 . The passenger seat 8 and the flight attendant seat 2 are mounted on the floor 22 of an aircraft. The passenger seat 8 and the flight attendant seat 2 are positioned at a distance 20 from one another. In this case, the flight attendant seat 2 is behind the passenger seat 8 . Behind is defined in this case as the direction located in the back area of a passenger during normal usage of the passenger seat 8 .
The passenger seat 8 is mounted on the floor 22 using a pedestal 14 . The armrest 16 and seat cushion 12 are mounted on the pedestal 14 . A passenger may sit on the seat cushion 12 . In this case, his viewing direction points to the front. The back rest 10 is movably mounted on the armrest 16 . The back rest 10 may be moved in the direction of the flight attendant seat 2 .
The distance 20 defines the movement space of the back rest 10 of the passenger seat 8 . During a movement of the back rest 10 in this area 20 , there is no obstruction of the back rest 10 by the flight attendant seat 2 .
FIG. 1 shows a seated position. The back rest 10 of the passenger seat 8 is in its upright position, i.e., it is essentially perpendicular to the floor surface 22 . A fixed distance 20 thus results between back rest 10 and flight attendant seat 2 , in particular the partition wall 4 of the flight attendant seat 2 . The flight attendant seat 2 has a seat surface 6 . For example, the second furnishing 2 may have a flap 6 which is folded down by the weight of a user. If the weight of a user falls away, the flap 6 may fold away automatically and cause a movement of at least a part of the second furnishing 2 . However, an automatic mechanism may also be a trigger device, for example, particularly a button or a lever, after whose actuation the movement of the part of the second furnishing 2 is triggered.
In FIG. 1 , the seat surface 6 is perpendicular to the floor 22 . The position of the seat surface 6 perpendicular to the floor 22 means that the flight attendant seat 2 is not used. To use the flight attendant seat 2 , the seat surface 6 is folded parallel to the floor surface 22 . A flight attendant may thus sit on the seat surface 6 .
The distance of the fixed mounting of the flight attendant seat 2 having attachment 24 on the floor 22 and the fixed mounting of the passenger seat 8 using floor frame 14 on the floor 22 determines the distance 20 between back rest 10 and partition wall 4 . Distance 20 is the clearance zone in whose extension the back rest may be moved in the direction of partition wall 4 .
The clearance zone required for inclining the back rest 10 results from the dimensions of the passenger seat 8 . At a height of the back rest 10 of approximately 1100 mm, a space requirement 20 of approximately 150 to 230 mm results. The clearance zone 20 may restrict the required clearance zone for the complete inclination of the back rest 10 because of the mounting of the passenger seat 8 and the flight attendant seat 2 , which is too close.
The seat surface 6 of the flight attendant seat 2 is in a horizontal position during a first mode of operation, so that the cabin personnel and/or a flight attendant may take a seat on this seat surface 6 .
FIG. 2 also shows the seat back rest 26 indicated in a completely inclined position. The flight attendant seat 2 is divided into two separate parts by the joint 28 . The two parts of the flight attendant seat are an upper part 4 a and a lower part 4 b . It may be seen that there is an overlap of the back rest 26 and upper part 4 a of the flight attendant seat 2 . In order to allow the complete inclination of the back rest 26 , the upper part 4 a of the flight attendant seat 2 must be folded away in order to free a spatial area for the back rest 26 . In other embodiments, the upper part 4 a of the flight attendant seat 2 may be lowered into the lower part 4 b , as depicted by arrow A, thus reducing the height of the flight attendant seat telescopically. The space thus obtained may be used for a part of the first furnishing, particularly for the movement of a part of the first furnishing.
FIG. 3 shows an inclination of the upper part 4 a counterclockwise around the joint 28 of the flight attendant seat 2 . The lower part 4 b of the flight attendant seat 2 is fixed on the floor 22 using attachment 24 and is not inclined.
The passenger seat 8 is also fixed on the floor 22 using the pedestal 14 . The distance between the lower part 4 b of the flight attendant seat 2 and the pedestal 14 is thus permanently predefined. Via inclination of the upper part 4 a , space may be provided above the lower part 4 b of the flight attendant seat 2 in order to allow the complete inclination of the back rest 26 . FIG. 3 shows the arrangement in a cruise mode or during flight operation.
During the flight in a second mode of operation, the flight attendants perform their activities and the flight attendant seat 2 remains free. This means that the seat surface 6 is folded essentially parallel to the upper part 4 a of the flight attendant seat 2 . The inclination of the back rest 26 in the direction of flight attendant seat 2 may be selected individually between the maximum inclination 26 and the vertical position 10 of the back rest as desired by the passenger. There is no restriction in relation to other passenger seats at other locations. This means that the flight attendant seat 2 and/or the upper part 4 a of the flight attendant seat 2 does not obstruct the inclination of the back rest 26 .
The upper part 4 a may be inclined automatically when the seat surface 6 is folded back into the position essentially parallel to the upper part 4 a . The lock of the flight attendant seat in the first mode of operation may be performed by folding down the seat surface of the flight attendant. This principle does not have to be operated by the flight attendant personnel. A coupling between the back rest 10 and upper part 4 a of the flight attendant seat 2 is also possible, so that the upper part 4 a of the flight attendant seat 2 is moved simultaneously with inclination of the back rest 10 . Like a flight attendant seat 2 , a partition wall may also be equipped with a buckle joint 28 .
FIG. 4 shows the passenger seat 8 and the flight attendant seat 2 in the first mode of operation. The first mode of operation identifies the takeoff or landing phase of an aircraft. In this case, the seat surface 6 is folded horizontally to the aircraft floor 22 . A flight attendant may take a seat on the seat surface 6 in this phase. The flight attendant seat 2 is positioned on the seat rail 32 using linear or friction bearings 30 . In the first mode of operation, the flight attendant seat is in the position on the seat rail 32 identified by the letter A.
The back rest 10 of the passenger seat and the partition wall 4 of the flight attendant seat 2 thus have a distance 34 . The passenger seat 8 is attached using pedestal 14 to the aircraft floor 22 or also to the seat rail 32 .
The seat rail 32 corresponds to a seat rail typical in aircraft construction and is positioned below the surface of the floor 22 . The friction bearing 30 allows displacement of the complete flight attendant seat 2 parallel to the floor surface 22 . The flight attendant seat 2 is attached in position A using a constructively secure lock. This secure lock may be easily opened by an operator, however, in order to allow easy displacement of the flight attendant seat 2 .
FIG. 5 shows the arrangement according to the present invention of the passenger seat 8 and the flight attendant seat 2 in a second mode of operation. The second mode of operation, for flight operation or cruise mode, is to allow inclination of the back rest 26 of the passenger seat 8 . In order to obtain the clearance zone 36 for the inclination of the back rest 26 , the flight attendant seat 2 is displaced during the flight into position B. The distance 36 corresponds to the maximum inclination of the back rest 26 from the vertical position.
The distance or clearance zone 36 in relation to the vertical inclination of the back rest 10 is greater in this position than the distance 34 in position A. Position B may be located in a work space or an exit space not used during the flight phase. During entry into and/or exit out of the aircraft, passengers near an entry or exit are to have sufficient movement freedom to walk and move. The rest 10 of a passenger seat remains in its vertical position.
For comfortable entry and exit, a specific space is provided for the aircraft attendant seat near the passenger seat. The entry/exit area is thus enlarged.
However, during the flight, the space in front of the exit is not used. Therefore, the flight attendant seat 2 may be displaced and/or moved into the space, in order to thus provide a clearance zone 36 for inclining the back rest 26 . In position B, the flight attendant seat 2 is also attached using a constructively secure lock. The adjustment from position A into position B and vice versa may also occur automatically. During the flight, the flight attendant seat 2 is not used by the flight attendant. Therefore, the seat surface 6 is folded against the partition wall 4 of the flight attendant seat in flight operation.
A linear bearing has the advantage that during a displacement of the entire flight attendant seat 2 , the flight attendant seat 2 is usable unrestrictedly.
FIG. 6 shows the top view of an interior of an aircraft fuselage 42 . Passenger seats are positioned in seat rows between the aircraft bow area 44 and the aircraft stern area 46 . Two diametrically opposite doors 40 and an entry/exit or working area 38 are located in each of the two occupancy areas 48 . Each occupancy area 48 also contains an arrangement of a passenger seat 8 having a flight attendant seat 2 positioned between passenger seat 8 and entry/exit area 38 .
In order to provide the largest possible entry and exit area 38 , the flight attendant seat 2 is positioned as close as possible to the passenger seat 8 . The flight attendant seat 2 or cabin attendant seat 2 thus obstructs a maximum inclination of the back rest 26 of the passenger seat 8 . In order to allow the inclination of the back rest 10 of the passenger seat 8 during the flight, the flight attendant seat 2 or part of the flight attendant seat 2 may be displaced and/or inclined into the entry or exit area 38 , particularly the occupancy area 48 .
FIG. 7 shows a detail from FIG. 6 . The aircraft fuselage 42 having the entry/exit doors 40 is shown. To board the aircraft, the entry/exit area 38 is used by the passengers. The free surface of the entry/exit area 38 is to be selected as largest possible in order to make the entry/exit of the passengers easier. Therefore, the flight attendant seat 2 is positioned as close as possible to the passenger seat 8 . During the entry phase, the back rest 10 of the passenger seat 8 is in an upright position.
During the flight phase, the entry area 38 is not used. Therefore, the flight attendant seat 2 or part of the flight attendant seat 2 may use the entry/exit area 38 and/or the work space 38 .
In addition, it is to be noted that “comprising” does not exclude other elements or steps and “a” or “an” does not exclude multiples. Furthermore, it is to be noted that features or steps which have been described with reference to one of the above exemplary embodiments may also be used in combination with other features or steps of other exemplary embodiments described above. Reference numbers in the claims are not to be viewed as a restriction.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. | An arrangement, includes a first furnishing and a second furnishing, at least one part of the first furnishing being movable in the direction of the second furnishing, and at least one part of the second furnishing being movable to free a space for receiving the at least one part of the first furnishing. | 1 |
TECHNICAL FIELD
[0001] The present invention relates to photodiode manufactured by semiconductor for the purpose of the operation in super frequency, in a terahertz band in particular.
BACKGROUND ART
[0002] As a method of generating terahertz band (0.3˜3 THz) radiation light based on an optical technique, a device has been conventionally used that mainly uses optical nonlinear material or optical electricity-conducting material. Optical electricity-conducting material and photodiode are both one type of a light-receiving device. Recently, attention has been paid on a photomixing method using photodiode (the conversion of optical beat to an electric signal) because of the high efficiency. With regard to a case using photodiode operating at a communication waveband (wavelength of 1.5 gm), the antenna radiation of a few ρW level at 1 THz has been already reported and has been considered as a promising technique. The use of a high-performance photodiode operating at a THz band provides a remarkably-improved spectroscopic performance than in the case where a conventional light-receiving device is used. As a result, an application has been expected for example in which a substance-specific absorption spectrum called as a fingerprint spectrum is observed so that a lot of substances (e.g., medical agents) can be determined.
[0003] However, the conventional photodiode structure developed for the purpose of application for an optical communication or a measurement instrument device (having a bandwidth up to 100 GHz at the maximum) is manufactured so as to have a response characteristic having a wide bandwidth suitable for digital application. Thus, the conventional photodiode is not always suitable for the THz band operation. The reason is that, while a typical conventional photodiode has an operation frequency range of about 3 dB bandwidth, in a THz application a wide frequency band including a frequency range much higher than a 3 dB bandwidth is typically used.
[0004] The photodiode true response is obtained by a delay id caused by the transit time of electrons or the transit time of both of electrons and holes among carriers (electrons and holes) generated in a light absorption layer. Generally, id can be reduced by reducing the thickness of a depletion layer. This reduction of the thickness of the depletion layer is still one factor required for a higher speed of transit. However, since the reduction of the thickness of the depletion layer requires an increase of the junction capacitance, the photodiode junction size or operation current must be adjusted for optimization. No detailed result has been reported with regard to the photodiode operation focusing on the THz operation as described above.
[0005] Furthermore, in the case of a communication photodiode, not only a bandwidth but also a light-receiving sensitivity are considered important. On the other hand, there is a difference in requirement such as that the maximum output is regarded as an important in a THz application. Thus, requirements are different. Although in the THz application, a light-receiving sensitivity having a fixed level or more must be secured, its importance is low. Generally, the operation current is maximized in order to increase the THz output, thus causing a disadvantage of the self heating of the photodiode. Under such conditions, how much THz output can be taken out with regard to fixed operation current is most important than the light-receiving sensitivity. No specific report has been found with regard to the design of a THz photodiode from the viewpoint as described above.
Conventional Example 1
[0006] For example, Non-patent Publication 1 reports the THz output characteristic of a “photodiode module” manufactured using a Uni-Traveling-Carrier Photodiode (UTC-PD) and a semiconductor chip obtained by integrating a log periodic antenna on an InP substrate. The THz output declines with a frequency and, when about 300 GHz is exceeded, the tendency of the decline becomes rapid. It is considered that the characteristics of the photodiode modules as described above include a frequency dependency composed of a superimposed combination of a response decline due to the true bandwidth and a response decline due to the junction capacitance of the photodiode. This will be described briefly in the following section.
[0007] In the most simplified form, the photodiode true response R 1 (φ) is represented by the following formula using the delay id due to the carrier transit time when assuming that the light modulation frequency (=optical beat frequency) is f(2πf=ω).
[0000] R 1(ω)=1/[1+ jωτd]
[0000] The response R 2 (ω) related to a RC constant, which is determined by the photodiode junction capacitance Cj and the pure resistance antenna load RL, is approximated by the following formula.
[0000] R 2(ω)=1/[1+ jωCjRL]
[0000] Thus, the frequency characteristic of the THz output is represented by the following formula.
[0000] P out(ω)=1/[| R 1(ω)|×| R 2(ω)|] 2 ∝1/ω 4 (high-frequency area: ω>>1/τ d and ω>>1/ Cj×RL )
[0000] The measurement value of the THz output observed in Non-patent Publication 1 also shows a tendency of ∝1/ω 4 in a range exceeding about 400 GHz. Specifically, it is considered that the true response of the photodiode used in Non-patent Publication 1 is not special and has a substantially typical frequency characteristic.
Conventional Example 2
[0008] Effenberser et al. suggest a partial absorption layer-type pin photodiode (see Non-patent Publication 2). FIG. 7 illustrates the band diagram. This photodiode is configured so that an n-type contact layer 71 has thereon a layered structure of an electron drift layer 72 , a light absorption layer 73 , a p-type contact buffer layer 74 , and a p-type contact layer 75 and the p-type contact layer 75 has thereon a p electrode 76 . The electron drift layer 72 (═depletion layer) having a certain thickness and having no light absorption is inserted to the n contact layer 71 having the pin-type structure. Among carriers generated by light absorption, holes directly flows to the p-type contact buffer layer 74 . On the other hand, electrons passes the electron drift layer 72 to subsequently reach the n-type contact layer 71 .
[0009] The electron speed higher than the hole speed prevents, even when the electron travels for a relatively-long distance, the entire current response from being deteriorated. Specifically, the 3 dB bandwidth determined by the carrier transit time is prevented from declining when the thickness of the electron drift layer has a certain value or less. As a result, the junction capacitance can be reduced without deteriorating the bandwidth, and entire response characteristic of the photodiode including an RC constant will be improved.
[0010] However, what is discussed is a photodiode structure having the 3 dB bandwidth of only about 30-40 GHz. No guideline for THz application is disclosed. The following section will describe, based on a simple model, a case where a “partial absorption layer-type” pin-type photodiode structure suggested in Non-patent Publication 2 is scaled from the viewpoint of a THz application.
[0011] The light absorption layer of InGaAs is used. While the thickness of the entire depletion layer including the light absorption layer 73 (layer thickness of Wa) and the electron drift layer 72 is being maintained at 0.23 μm, the light absorption layer thickness Wa is changed within a range of 600 A to 2200 A. The current response (i.e., the above-described frequency response due to the transit time of both of electrons and holes) is calculated based on an assumption that the electron travel speed is 6×10 7 cm/s in a speed overshoot status (in contrast with the case of Non-patent Publication 2) and the travel speed has a normal value of 0.45×10 cm/s.
[0012] FIG. 8 shows the simulation result of the THz response. In the case of the Wa=2200 A structure close to a conventional pin-type structure having a thick InGaAs light absorption layer, it is understood that the frequency response [R 22 ( f ) in FIG. 8 ] is composed of a hole response component declining at about 100 GHz and an electronic response component increasing to a frequency of 100 GHz or more. When Wa=2200 A, the 3 dB bandwidth is undesirably governed by the hole current response. Reduce of Wa as from 1400 A to 600 A cause the response [R 14 ( f ) and R 06 ( f )] increases to the high frequency side. When Wa=600 A, the 3 dB bandwidth increases to 1.1 THz. Due to such an increase of the 3 dB bandwidth, when an asymmetric structure is provided in which the light absorption layer in the depletion layer is provided to the p contact side, the contribution of the induction current components of the electrons increases relative to the contribution of the induction current components of the holes, thus resulting in the entire response governed by the electron response.
[0013] On the other hand, with regard to the responses on a operation in the region of 1 THz or more in all of the structures compared here, a 10 dB reduction bandwidth (f10 dB) exists in the vicinity of 2 THz and thus no significant difference is found. A response on a operation near 3 THz rapidly decreases to a value of about 1/50 or less when compared with a low-frequency area. In the case of the Wa=600 A structure having a superior 3 dB bandwidth, a tendency of a response decrease on a operation in from 2 THz to 3 THz is more remarkable.
CITATION LIST
Non Patent Literature
[0000]
NPL1: Hiroshi Ito et al., J. Lightwave Tech. Vol. 23, No. 12, pp. 4016-4021, 2005
NPL2: F. J. Effenberger and A. M. Joshi, J. Lightwave Tech. Vol. 14, No. 8, pp. 1859-1846, 1996
SUMMARY OF INVENTION
Technical Problem
[0016] As described above, the operation in THz of the photodiode has been already reported. A tendency in a reverse proportion to approximately the fourth power of the frequency has been experimentally observed. However, it has been not yet clarified what a kind of photodiode structure should be selected in order to improve a THz frequency range much higher than f3 dB output characteristic.
[0017] It is an objective of the present invention to provide a photodiode that can provide a THz operation with a stable output (i.e., a photodiode that can provide a high output to fixed operation current).
Solution to Problem
[0018] In order to solve the above disadvantage, the invention according to one embodiment is a photodiode having a pin-type semiconductor structure including a semiconductor layer structure obtained by sequentially layering an n-type contact layer, a low concentration layer, and a p-type contact layer and an n electrode and a p electrode connected to the n-type contact layer and the p-type contact layer, respectively. During the operation, the low concentration layer is depleted. The low concentration layer is obtained by layering an electron drift layer, a light absorption layer, and a hole drift layer while being abutted to the n-type contact layer.
BRIEF DESCRIPTION OF DRAWINGS
[0019] FIG. 1A illustrates photodiode of the first embodiment;
[0020] FIG. 1B illustrates the photodiode of the first embodiment;
[0021] FIG. 2A illustrates the photodiode of the second embodiment;
[0022] FIG. 2B illustrates the photodiode of the second embodiment;
[0023] FIG. 3A illustrates the calculation result of the THz response output of the photodiode of the second embodiment;
[0024] FIG. 3B illustrates the calculation result of the THz response output of the photodiode of the second embodiment;
[0025] FIG. 4 illustrates the relation between the band diagram and the field strength with regard to the photodiode of the third embodiment;
[0026] FIG. 5 illustrates the relation between the band diagram and the field strength with regard to the photodiode of the fourth embodiment;
[0027] FIG. 6 illustrates the relation between the band diagram and the field strength with regard to the photodiode of the fifth embodiment;
[0028] FIG. 7 illustrates the band diagram of a conventional photodiode module that can provide THz output; and
[0029] FIG. 8 illustrates the simulation result of the THz response output in a conventional photodiode module.
DESCRIPTION OF EMBODIMENTS
[0030] The following section will describe in detail an embodiment of the present invention.
First Embodiment
[0031] FIGS. 1A and 1B illustrate the photodiode. FIG. 1A illustrates the layer configuration thereof. FIG. 1B illustrates the band diagram thereof.
[0032] As shown in FIG. 1A , in the photodiode of this embodiment, a semi-insulating InP substrate 10 has thereon a layered structure of an n-type contact layer 11 consisting of InP; a low-impurity concentration electron drift layer 12 consisting of InGaAsP (bandgap levy; a low-impurity concentration InGaAs light absorption layer 13 ; a low-impurity concentration hole drift layer 14 consisting of InAlGaAs (bandgap 1 eV); a p-type contact buffer layer 15 consisting of InP; and a p-type contact layer 16 consisting of InAlGaAs. The n-type contact layer 11 has thereon an n electrode 18 . The p-type contact layer 16 has thereon a p electrode 17 .
[0033] Within the active region of this photodiode, as shown in the band diagram of FIG. 1B , light absorption causes electrons 19 a and holes 19 b to occur, thus inducing the current due to the carrier travel.
[0034] The method of manufacturing the photodiode may be a method similar to the conventional one to manufacture an ultrahigh-speed photodiode. For example, the MO-VPE method is used to manufacture a substrate obtained by subjecting, on the semi-insulating InP substrate 10 , a layered structure of the n-type contact layer 11 to the p-type contact layer 16 to epitaxial growth. The device processing is carried out by performing a chemical etching on the first mesa including layers from the InAlGaAs-p-type contact layer 16 to the InGaAsP-electron drift layer 12 and the second mesa of the InP-n contact layer 11 . The device processing is performed by further forming the p electrode 17 and the n electrode 18 by metal vapor deposition to form the other required separation insulating film and metal wiring for example.
[0035] When the photodiode is applied a reverse bias voltage via the p electrode 17 and the n electrode 18 , then the InGaAsP electron drift layer 12 , the InGaAs light absorption layer 13 , and the InAlGaAs hole drift layer 14 are depleted, thus inducing an electric field. When signal light enters in this status, electrons and holes are generated in the InGaAs light absorption layer 13 as described above. When these carriers travel through the depletion layer, induction current is generated in an external circuit. The hole drift layer 14 and the electron drift layer 12 have different material systems because the hole drift layer 14 and the electron drift layer 12 have small valance band discontinuity and small conduction band discontinuity to InGaAs, respectively, and thus the effect of a carrier trap effect due to a band discontinuity is reduced in a low electric field.
[0036] The above photodiode is mainly characterized in that, although this diode is based on a pin-type diode structure, the hole drift layer is inserted to the p-type contact layer side. A conventional pin-type diode is configured so that an electron drift layer is inserted to the n-type contact layer side, as has been already disclosed in Non-patent Publication 2. However, no disclosure is found according to which the hole drift layer is inserted to the p-type contact layer side. This is caused by the fact that the conventional pin-type diode has been required to provide a wide bandwidth and efficient device. Specifically, 3 dB bandwidth or output has been required and thus the hole drift layer not contributing to a wide bandwidth and efficient device has been considered as an unnecessary layer. In the case of the technique disclosed in Non-patent Publication 2, the electron speed is higher than that of the holes. Thus, an advantage is obtained according to which the 3 dB bandwidth can be expanded by increasing the 3 dB bandwidth or by reducing the junction capacitance.
[0037] On the contrary, the photodiode of this embodiment has a tendency according to which, when the hole drift layer is inserted to the p-type contact layer side, the contribution of the current component of holes having a slow speed is increased and the 3 dB bandwidth declines despite the intention. Specifically, with regard to the typical objective of improving the 3 dB bandwidth, the diode structure of the photodiode of this embodiment has no significance. However, under conditions having a fixed depletion layer thickness, it is clear that the transit time is reduced in proportion to the reduction of the average travel distance of the electrons generated in the InGaAs light absorption layer 13 . Finally, the characteristic is that the frequency range of the electron current response is expanded and the response increases in the THz frequency region on the contrary.
[0038] In the above description of the embodiment, material lattice-matched to InP was selected and the hole drift layer was composed of InAlGaAs and the electron drift layer was composed of InGaAsP. However, the photodiode of this embodiment has basically no remarkable limitation by the material system and thus has a design concept that can be commonly applied.
Second Embodiment
[0039] The photodiode of this embodiment has the InInGaAs light absorption layer of which position in the depletion layer is changed from that of the photodiode of the first embodiment. FIGS. 2A and 2B illustrate the band diagram in the photodiode of the second embodiment. In the photodiode having the band diagram shown in FIG. 2A , the light absorption layer 23 a is provided closer to the p-type contact layer 16 and the hole drift layer 24 a has a thin thickness and the electron drift layer 22 a has a thick thickness. On the contrary, in the photodiode having the band diagram shown in FIG. 2B , the light absorption layer 23 b is provided closer to the n-type contact layer 11 , the hole drift layer 24 b has a thick thickness, and the electron drift layer 22 b has a thin thickness. The other configurations are the same as those of the configuration shown in the first embodiment.
[0040] The photodiode of the present invention has a main feature that the hole drift layers 24 a and 24 b are inserted to the p-type contact layer 15 side (i.e., the positions of the light absorption layers 23 a and 23 b in the depletion layer are adjusted). The electron drift layers 22 a and 22 b as well as the hole drift layers 24 a and 24 b have a thickness adjusted according to the required light response characteristic. The configuration of FIG. 2A is not superior or inferior to the configuration of FIG. 2B . The photodiode of this embodiment may be set so as to maximize the response in a required frequency range by adjusting the position of the light absorption layer in the depletion layer. The following section will describe a difference in the response characteristic depending on the structure.
[0041] The following section will compare the following four types of structures. Table 1 shows parameters. FIGS. 3A and 3B show the result of the calculation of the THz response output in the photodiode of this embodiment. FIG. 3A is a double logarithm graph illustrating the calculation result of the THz response output in a range from 10 GHz to 1×10 4 GHz. FIG. 3B is a single logarithm graph illustrating the calculation result of the THz response output in a range from 10 GHz to 5×10 3 GHz. In FIGS. 3A and 3B , for the comparison of (the logarithmic axis and the linear axis), such a structure is also included that has a hole drift layer having a thickness of zero based on the structure suggested in Non-patent Publication 2 (response 0). The curve at the response 0 is the same curve of R 06 ( f ) of FIG. 8 .
[0000]
TABLE 1
Structure parameters for simulation of
photodiode of the present invention
Light
Electron
Total
Hole drift
absorption
travel
depletion
Curve in
layer
layer
layer
layer
the
thickness
thickness
thickness
thickness
drawing
Response 1
600 Å
600 Å
1100 Å
2300 Å
Rleft2(f)
Response 2
900 Å
600 Å
800 Å
2300 Å
Rcent2(f)
Response 3
1200 Å
600 Å
500 Å
2300 Å
Rright2(f)
Response 0
0 Å
600 Å
1700 Å
2300 Å
Rhbpin(f)
[0042] In the case of the conventional structure having no hole drift layer (curve of response 0), the 3 dB bandwidth is 1.1 THz (the same curve as R 06 ( f ) of FIG. 8 ). The comparison shown in FIG. 3A clearly shows that an increase of the hole drift layer from 600 A through 900 A to 1200 A causes the 3 dB bandwidth to rapidly decline to about 120 GHz. On the other hand, according to FIG. 3B , the response in the THz region shows that an increase of the hole drift layer causes an increase of the skirt of the frequency response. When the operation frequency exceeds 2 THz, the conventional structure (response 0) shows a sharp decline of the response output in spite of the fact that the photodiode of this embodiment shows substantially no decline of the response output. Thus, it can be recognized that the photodiode of the present invention is superior to the conventional structure.
[0043] The response decline in the conventional structure is seen at 3 THz. On the other hand, this photodiode has a structure in which the response decline shifts to the high frequency side in accordance with the increase of the thickness of the hole drift layer. In particular, in the curve shown by the response 3 having the hole drift layer thickness of 1200 A, the response characteristic is relatively flat until 5 GHz is reached. It can be consequently recognized that the photodiode of this embodiment has a structure that can effectively provide the electron response in the THz frequency region by sacrificing the 3 dB bandwidth.
[0044] As described above, the photodiode of this embodiment has an effect similar to that of the photodiode of the first embodiment. Furthermore, the photodiode of this embodiment can be adjusted to provide a required output in a desired frequency range by changing the position of the light absorption layer in the depletion layer.
Third Embodiment
[0045] The photodiode of this embodiment has a so-called step-type field strength profile in which, the field strength of the light absorption layer is higher than the field strengths of the electron drift layer and the hole drift layer of the photodiode of the first embodiment. FIG. 4 illustrates the relation between the band diagram of photodiode of the third embodiment and the field strength. As shown in FIG. 4 , the photodiode of this embodiment includes an electron drift layer 32 , an InGaA light absorption layer 33 , and a hole drift layer 34 instead of the electron drift layer 12 , the light absorption layer 13 , and the hole drift layer 14 of the first embodiment. The electron drift layer 32 has an impurity concentration distribution consisting of InGaAsP (bandgap 1 eV). The InGaA light absorption layer 33 has a low-impurity concentration. The hole drift layer 34 has an impurity concentration distribution consisting of InAlGaAs (bandgap 1 eV). The electron drift layer 32 has an n-type doping layer 32 n at the light absorption layer 33 side constituting a part thereof. The hole drift layer 34 has a p-type doping layer 34 p at the light absorption layer 33 side constituting a part thereof. The ionized donor charge amount of the n-type doping layer 32 n and the ionized acceptor charge amount of the p-type doping layer 34 p are adjusted depending on a required difference in the field strength.
[0046] Since the n-type doping layer 32 n and the p-type doping layer 34 p have a narrow width, a step-like field strength profile as shown in FIG. 4 is obtained. Thus, the light absorption layer 33 has a field strength relatively higher than those of the electron drift layer 32 and the hole drift layer 34 . When the light absorption layer 33 has a high field strength, electrons generated by light absorption can be accelerated within a shorter time to accelerate the response of the photodiode of this embodiment (i.e., the response of the THz region). The increase of the field strength of the light absorption layer 33 also has an action to suppress a change of the potential in the electron drift layer 32 to prevent the electron kinetic energy from being excessively high. Another structure also may be used in which a complicated structure is prevented by not inserting the p-type doping layer 34 p and by inserting the n-type doping layer 32 n only. When the hole drift layer 34 the electron drift layer 32 have a lower electric field, another advantage is obtained according to which a required bias voltage of the photodiode declines and thus the operation with high heat generation is possible.
[0047] As described above, the photodiode of this embodiment can provide not only an effect similar to that of the photodiode of the first embodiment but also provide an improved response speed by having a step-like field strength profile.
Fourth Embodiment
[0048] The photodiode of this embodiment has been doped in electron drift layer and hole drift layer of the photodiode of the first embodiment. FIG. 5 shows the relation between the band diagram and the field strength of the photodiode of the fourth embodiment. As shown in FIG. 5 , the photodiode of this embodiment includes an electron drift layer 42 , an InGaA light absorption layer 43 , and a hole drift layer 44 instead of the electron drift layer 12 , the light absorption layer 13 , and the hole drift layer 14 of the first embodiment. The electron drift layer 42 is composed of InGaAsP (bandgap 1 eV) and is subjected to n-type doping. The InGaA light absorption layer 43 has a low-impurity concentration. The hole drift layer 44 is composed of InAlGaAs (bandgap 1 ev) and is subjected to p-type doping.
[0049] The electron drift layer 42 and the hole drift layer 44 are subjected to n-type and p-type dopings, respectively. Thus, no light signal is inputted. As shown in FIG. 5 , the electric field strength profile in which no electron or hole flows has a smooth trapezoidal shape. If a light signal is inputted, electrons travelling in the electron drift layer 42 and holes travelling in the hole drift layer 44 modulate the field strength distribution in the depletion layer 43 by the charge thereof. However, the present photodiode adjusts the n-type doping amount of the electron drift layer 42 and the p-type doping amount of the hole drift layer 44 so as to compensate the negative charge of the electrons during the operation and the positive charge of the holes.
[0050] The respective doping concentrations to be balanced with the carrier concentration are determined based on the operation current density. For example, when the operation at 5 mA current is performed in the junction area of 10 μm 2 , the current density is 5×10 4 A/cm 2 . The current density J is given by J=q×n×v based on the carrier concentration n, the carrier travel speed v, and the electron charge q. Thus, the electron charge density is calculated by J/(q×ve)=5.2×10 15 /cm 3 . The hole charge density is calculated by J/(q×vlh)=6.9×10 16 /cm 3 . In this manner, the n-type doping amount of the electron drift layer 42 and the p-type doping amount of the hole drift layer 44 are determined. In this manner, the structure is determined so that an appropriate electric field profile can be maintained at predetermined operation current. Thus, such a structure can be realized that has a good characteristic even at a higher photodiode operation current.
[0051] As described above, the photodiode of this embodiment can provide not only the same effect as that of the photodiode of the first embodiment but also an appropriate operation even at higher operation current.
Fifth Embodiment
[0052] The photodiode of this embodiment applys both of the step-like electric field profile shown in the third embodiment and the doping of the electron drift layer and the hole drift layer shown in the fourth embodiment. FIG. 6 shows the relation between the band diagram and the field strength of the photodiode of the fifth embodiment. As shown in FIG. 6 , the photodiode of the fifth embodiment uses an electron drift layer 52 , an InGaAs light absorption layer 53 , and a hole drift layer 54 instead of the electron drift layer 12 , the light absorption layer 13 , and the hole drift layer 14 of the first embodiment. The electron drift layer 52 is composed of InGaAsP (bandgap 1 ev) and is subjected to n-type doping. The InGaAs light absorption layer 53 has a low-impurity concentration. The hole drift layer 54 is composed of InAlGaAs (bandgap 1 ev) and is subjected to p-type doping. Furthermore, the electron drift layer 52 has the n-type doping layer 52 n having a higher concentration by the light absorption layer 53 constituting a part thereof. The hole drift layer 54 has the p-type doping layer 34 p having a higher concentration at the light absorption layer 33 side constituting a part thereof.
[0053] The photodiode of this embodiment uses a combination of the two functions of the step-like electric field profile described in the third embodiment as well as the n-type doping to the electron drift layer and the p-type doping to the hole drift layer described in the fourth embodiment. The light absorption layer 53 has a field strength relatively higher than those of the electron drift layer 52 and the hole drift layer 54 . Thus, electrons generated by light absorption can be accelerated within a shorter time to accelerate the current response and an appropriate operation can be performed even at operation current.
[0054] As described above, the photodiode of this embodiment can provide not only an effect similar to the photodiode of the first embodiment but also can accelerate the current response and can perform an appropriate operation even at high operation current.
[0000]
Reference Signs List
10
Substrate
11 and 71 N-type contact layer
12, 22a, 22b, 32, 42, 52, and 72
Electron drift layer
13, 23a, 23b, 33, 43, 53, and 73
Light absorption layer
14, 24a, 24b, 34, 44, and 54
Hole drift layer
15 and 74 P-type contact buffer layer
16
P-type contact layer
11
N-type contact layer
18
N electrode
16 and 75 P-type contact layer
17 and 76 P electrode
19a and 19e
electron
19b and 19h
Hole
32n N-type doping layer
34p P-type doping layer | A photodiode that can provide a THz operation with a stable output. A photodiode having a pin-type semiconductor structure includes a semiconductor layer structure and n and p electrodes. The semiconductor layer structure is obtained by sequentially layering an n-type contact layer, a low concentration layer, and a p-type contact layer. The low concentration layer is obtained by layering an electron drift layer, a light absorption layer, and a hole drift layer while being abutted to the n-type contact layer. The n electrode and the p electrode are connected to the n-type contact layer and the p-type contact layer, respectively. During operation, the low concentration layer is depleted. | 7 |
RELATED APPLICATIONS
[0001] This is a continuation-in-part of application Ser. No. 10/236,097, filed on Sep. 6, 2002, which is a continuation-in-part of application Ser. No. 09/841,844, filed on Apr. 25, 2001, which is a continuation-in-part of application Ser. No. 09/826,976, filed on Apr. 5, 2001, now U.S. Pat. No. 6,419,944, which is a continuation-in-part of application Ser. No. 09/563,651, filed on May 2, 2000, which is a continuation-in-part of application Ser. No. 09/476,643, filed on Dec. 31, 1999, now U.S. Pat. No. 6,177,077, which is a continuation-in-part of application Ser. No. 09/275,070, filed on Mar. 23, 1999, now U.S. Pat. No. 6,015,557, which is a continuation-in-part of application Ser. No. 09/256,388, filed on Feb. 24, 1999, now abandoned.
FIELD OF THE INVENTION
[0002] The present invention relates to novel methods of use of specific cytokine antagonists for the treatment of neuropsychiatric and neurological disorders in humans. More particularly, these cytokine antagonists are used in a new treatment of neuropsychiatric and neurologic diseases and disorders, including, but not limited to affective disorders, including unipolar and bipolar affective disorders; schizoaffective illness, schizophrenia, autism, depression, anorexia nervosa, obsessive-compulsive disorders, narcotic addiction, and smoking cessation/nicotine withdrawal; diseases and disorders of the brain; neurodegenerative disorders, including but not limited to Parkinson's Disease and Alzheimer's Disease; spinal cord injury, amyotrophic lateral sclerosis; headache syndromes, including, but not limited to migraine headaches and cluster headaches; neurologic disorders associated with neuropathic pain, including, but not limited to lumbar and cervical radiculopathy, low back pain, vertebral disc disease, fibromyalgia, post-herpetic neuralgia, and reflex sympathetic dystrophy; and chronic fatigue syndrome; utilizing specific anatomic methods of administration of these specific biologics. The delivery of these cytokine antagonists is performed by specific methods, most of which fall into the categories of perispinal administration or intranasal administration. Perispinal administration involves an anatomically localized injection performed so as to deliver the therapeutic molecule directly into the vicinity of the spine. Perispinal administration includes, but is not limited to the subcutaneous, intramuscular, interspinous, epidural, peridural, parenteral, or intrathecal routes, and may be perilesional or alternatively, particularly when treating diseases of the brain, remote from the ultimate site of pathology. Intranasal administration includes the delivery of these particular cytokine antagonists by instillation into the nasal passages, either by nasal spray or nasal inhaler. The cytokine antagonists of consideration are those designed to block the action of, inhibit, or antagonize the biologic effects of tumor necrosis factor-alpha (TNF) or interleukin-1 (IL-1). These antagonists may take the form of a fusion protein (such as etanercept); a monoclonal antibody (such as infliximab); a binding protein (such as onercept, Serono); an antibody fragment (such as CDP 870, Pharmacia); or other types of molecules which are potent, selective, and specific inhibitors of the action of these pro-inflammatory cytokines and are capable of being used by parenteral injection.
BACKGROUND OF THE INVENTION
[0003] Localized administration for the treatment of localized clinical disorders has many clinical advantages over the use of conventional systemic treatment. Locally administered medication after delivery diffuses through local capillary, venous, arterial, and lymphatic action to reach the anatomic site of pathology, or, alternatively, to reach the cerebrospinal fluid (CSF). In addition local administration of a biologic in the vicinity of the spine (perispinal administration) has the key advantage of improved delivery of the agent to the central nervous system (CNS). Local intranasal administration of a biologic is another method to improve delivery of the biologic to the CNS, and is discussed here as a method to treat neuropsychiatric disorders, including disorders of mood (depression, bipolar disorder) utilizing TNF antagonists or IL-1 antagonists.
[0004] All of the cytokine antagonists which are currently available have been developed for systemic administration. This is because all were developed to treat systemic illnesses, including rheumatoid arthritis, juvenile rheumatoid arthritis, psoriatic arthritis, or Crohn's Disease.
[0005] The use of cytokine antagonists to treat neurological disorders is discussed in several previous patents of this inventor, including U.S. Pat. Nos. 6,015,557, 6,177,077, 6,419,944 B2 and other pending applications of this inventor. This invention includes further applications of these ideas.
[0006] Perispinal administration of biologics when compared to systemic administration, carries with it one or more of the following advantages:
1) greater efficacy due to the achievement of higher local concentration; 2) greater efficacy due to the ability of the administered therapeutic molecule to reach the target tissue without degradation caused by hepatic or systemic circulation; 3) more rapid onset of action; 4) longer duration of action; 5) Potentially fewer side effects, due to lower required dosage; 6) greatly improved efficacy due to improved delivery of the therapeutic molecule to the CNS.
[0013] Clinical experience utilizing perispinal administration of etanercept for treating lumbar and cervical radiculopathy and other forms of neuropathic pain caused by vertebral disc disease has demonstrated the dramatic efficacy, and the extraordinarily rapid onset of action produced by perispinal administration of etanercept for these disorders. Perispinal administration of the other cytokine antagonists of consideration here, for treating other neurological disorders or for treating neuropsychiatric disorders, as partially enumerated above, shares the above advantages.
[0014] The therapeutic molecules of consideration here have many biologic effects. Etanercept, for example, in addition to being a potent anti-inflammatory also has important anti-apoptotic effects which may be of particular importance in treating neurodegenerative diseases, such as Alzheimer's Disease and Parkinson's Disease, where apoptosis plays a pathogenetic role.
[0015] Biologics have been developed which have been shown to offer dramatic clinical benefit for systemic illnesses in humans, even for those disorders which have not responded to large and repeated doses of corticosteroids. These biologics fall into the category of cytokine antagonists because they block, or antagonize, the biologic action of a specific cytokine which has adverse clinical effects. These cytokines include the pro-inflammatory cytokines interleukin-1 and TNF. For the purposes of this discussion, “antagonist”, “inhibitor”, and “blocker” are used interchangeably.
[0016] Specific inhibitors of TNF, only recently commercially available, now provide for therapeutic intervention in TNF mediated disorders. These agents have been developed to treat systemic illnesses, and therefore have been developed for systemic administration. Various biopharmaceutical companies have developed TNF antagonists to treat systemic illnesses: Immunex Corporation developed etanercept (Enbrel) to treat rheumatoid arthritis; Johnson and Johnson developed infliximab (Remicade) to treat Crohn's Disease and rheumatoid arthritis; D2E7, a human anti-TNF monoclonal antibody (Abbott) is being developed to treat rheumatoid arthritis and Crohn's Disease; Celltech is developing CDP 571 to treat Crohn's Disease and CDP 870 to treat rheumatoid arthritis; and Serono is developing onercept, a recombinant TNF binding protein (r-TBP-1) for treating rheumatoid arthritis and psoriasis/psoriatic arthritis.
[0017] Recent research has demonstrated that a new TNF antagonist can be manufactured from an existing molecule by subtracting a portion of the amino acid sequence from the molecule. This has the advantage of making the molecule smaller. This smaller molecule can be easier to manufacture and may have clinical advantages, such as reduced immunogenicity in the human in vivo. Therefore, the molecules of consideration here shall also include, in addition to those specified, any molecule which contains a fragment of any of the named molecules. A fragment shall be defined as an identical amino acid sequence 50% or greater in length of the original molecule and possessing TNF binding capability or interleukin-1 binding capability.
DESCRIPTION OF THE PRIOR ART
[0018] Pharmacologic chemical substances, compounds and agents which are used for the treatment of neurological disorders, trauma, injuries and compression having various organic structures and metabolic functions have been disclosed in the prior art. For example, U.S. Pat. Nos. 5,756,482 and 5,574,022 to ROBERTS et al disclose methods of attenuating physical damage to the nervous system and to the spinal cord after injury using steroid hormones or steroid precursors such as pregnenolone, and pregnenolone sulfate in conjunction with a non-steroidal anti-inflammatory substance such as indomethacin. These prior art patents do not teach the use of specific cytokine antagonists administered by the perispinal route as a way of treating neurological or neuropsychiatric disorders or diseases, as in the present invention.
[0019] U.S. Pat. No. 5,863,769 discloses using IL-1 RA for treating various diseases. However, it does not disclose administering cytokine antagonists by the perispinal route as a way of treating neurological or neuropsychiatric disorders or diseases.
[0020] U.S. Pat. No. 6,013,253 discloses using interferon and IL-1 RA for treating multiple sclerosis. However, it does not disclose administering cytokine antagonists by the perispinal route as a way of treating neurological or neuropsychiatric disorders or diseases.
[0021] U.S. Pat. No. 5,075,222 discloses the use of IL-1 inhibitors for treatment of various disorders. However, it does not disclose administering cytokine antagonists by the perispinal route as a way of treating neurological or neuropsychiatric disorders or diseases.
[0022] U.S. Pat. No. 6,159,460 discloses the use of IL-1 inhibitors for treatment of various disorders. However, it does not disclose administering cytokine antagonists by the perispinal route as a way of treating neurological or neuropsychiatric disorders or diseases.
[0023] U.S. Pat. No. 6,096,728 discloses the use of IL-1 inhibitors for treatment of various disorders. However, it does not disclose administering cytokine antagonists by the perispinal route as a way of treating neurological or neuropsychiatric disorders or diseases.
[0024] U.S. Pat. No. 6,277,969 discloses the use of anti-TNF antibodies for treatment of various disorders. However, it does not disclose administering cytokine antagonists by the perispinal route as a way of treating neurological or neuropsychiatric disorders or diseases.
[0025] U.S. Pat. No. 5,605,690 discloses the use of TNF inhibitors for treatment of various disorders. However, it does not disclose administering cytokine antagonists by the perispinal route as a way of treating neurological or neuropsychiatric disorders or diseases.
[0026] None of the prior art patents disclose or teach the use of localized administration of a cytokine antagonist as in the present invention as a way of treating neurological or neuropsychiatric disorders or diseases, in which the cytokine antagonist provides the patient with a better opportunity to heal, slows disease progression, or otherwise improves the patient's health.
[0027] Accordingly, it is an object of the present invention to provide a biologic administered through perispinal administration as a new method of pharmacologic treatment of neurological or neuropsychiatric diseases or disorders such that the use of these biologics will result in the amelioration of these conditions.
[0028] Another object of the present invention is to provide cytokine antagonists for providing suppression and inhibition of the action of specific cytokines in a human to treat neurological or neuropsychiatric diseases or disorders.
[0029] Another object of the present invention is to provide cytokine antagonists that produce biologic effects in patients with neurological or neuropsychiatric diseases or disorders by inhibiting the action of specific cytokines in the human body for the immediate, short term (acute conditions) and long term (chronic conditions), such that these biologic effects will produce clinical improvement in the patient and will give the patient a better opportunity to heal, improve cognitive function, slow disease progression, prevent neurological damage, reduce pain, or otherwise improve the patient's health.
[0030] Another object of the present invention is to provide cytokine antagonists, using anatomically localized administration in the vicinity of the spine as the preferred forms of administration, that provide therapeutic benefit utilizing either acute or chronic treatment regimens for treating neurological or neuropsychiatric diseases or disorders.
SUMMARY OF THE INVENTION
[0031] The present invention provides methods for treating neurological or neuropsychiatric diseases or disorders in humans by administering to the human a therapeutically effective dose of a specific biologic. The biologics of consideration include antagonists of tumor necrosis factor-alpha or of interleukin-1. The administration of these biologics is performed by specific methods, most, but not all of which fall into the categories of anatomically localized administration involving perispinal or intranasal delivery. Anatomically localized administration involving perispinal use includes, but is not limited to the subcutaneous, intramuscular, interspinous, epidural, peridural, parenteral or intrathecal routes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] Perispinal administration is a novel new concept for a delivery method for cytokine antagonists for treating neurological or neuropsychiatric diseases.
[0033] For the purposes of this discussion, “perispinal” means in the anatomic vicinity of the spine. For this discussion “anatomic vicinity” is generally defined as within 10 centimeters, or functionally defined as in close enough anatomic proximity to allow the therapeutic molecules of consideration herein to reach the spine and/or the subarachnoid space surrounding the spinal cord in therapeutic concentration when administered directly to this area. For the treatment of brain disorders, such as Alzheimer's, perispinal administration is effective because it delivers the biologic to the CNS in a therapeutic amount. This is accomplished through enhanced delivery of the therapeutic molecule to the CNS, either by direct diffusion or via enhanced delivery into the cerebrospinal fluid (CSF) which is present in the thecal sac. This usually occurs without direct intrathecal injection, but rather by diffusion from the peridural space into the subarachnoid space. Direct injection of these specific cytokine antagonists into the CSF (intrathecal administration) is also a form of localized anatomic administration and can be accomplished by the perispinal route.
[0034] One of the advantages of perispinal delivery is that administration is simplified. For example, administration for the treatment of an annular tear of an intervertebral disc in the lumbar spine is effective by the interspinous route adjacent to the involved disc. This route is simple and safe. Hemorrhage due to the use of long or large bore needles is minimized because perispinal administration, by the subcutaneous route, requires only a short, narrow bore needle. Time-consuming and difficult epidural injection is not necessary. Epidural administration, for the purposes of this patent, is also a form of perispinal administration, and, in certain clinical circumstances may be the delivery method of choice, despite its greater difficulty and greater risk. Local perispinal administration also has the advantage of providing a depot of therapeutic medication in the surrounding tissue, which will provide therapeutic levels of medication to the treatment site for a prolonged period of time. This decreases the necessity for another injection of medication. Additionally, administering medication locally limits the exposure of the medication to the systemic circulation, thereby decreasing renal and hepatic elimination of the medication, and decreasing exposure of the medication to systemic metabolism. All of these factors tend to increase the therapeutic half-life of the administered cytokine antagonist. Intranasal administration is also a form of localized anatomic administration. It shares the above advantages with perispinal administration, and has the additional advantage of delivering the biologic to the area (upper nasal passages) directly adjacent to the brain. Additionally the biologics are delivered in this same manner directly to branches of the olfactory nerve, providing another route of delivery to the CNS. Taken together, all of these forms of localized anatomic administration have significant clinical advantages over the various forms of systemic administration previously used to deliver these cytokine antagonists. These forms of systemic administration include the intravenous route; the intramuscular route, when the site of intramuscular administration is remote from the site of pathology; the subcutaneous route, when the site of subcutaneous administration is remote from the site of pathology (such as an abdominal, thigh, or arm administration for the treatment of sciatica); or other methods of administration which rely on the use of the systemic circulation to deliver the medication to the target area of pathology.
[0035] For the sake of this invention, the following definitions also apply: perilesional is defined as in anatomic proximity to the site of the pathologic process being treated; and peridural is defined as in anatomic proximity to the dura of the spinal cord. The “interspinous route” for the purposes of this patent, is defined as parenteral injection through the skin in the midline, in the interspace between two spinous processes, to deliver the therapeutic molecule in anatomic proximity to the spine.
[0036] Biologics to be used for the purposes of this patent fall into the general categories of TNF antagonists or interleukin-1 antagonists.
[0037] TNF antagonists include, but are not limited to the following: etanercept (Enbrel®—Amgen); infliximab (Remicade®—Johnson and Johnson); D2E7, a human anti-TNF monoclonal antibody (Knoll Pharmaceuticals, Abbott Laboratories); CDP 571 (a humanized anti-TNF IgG4 antibody); CDP 870 (an anti-TNF alpha humanized monoclonal antibody fragment), both from Celltech; soluble TNF receptor Type I (Amgen); pegylated soluble TNF receptor Type I (PEGs TNF-R1) (Amgen); and onercept, a recombinant TNF binding protein (r-TBP-1) (Serono). Antagonists of interleukin-1 include, but are not limited to Kineret® (recombinant IL1-RA, Amgen), IL1-Receptor Type 2 (Amgen) and IL-1 Trap (Regeneron).
[0038] In one preferred embodiment a patient with bipolar affective disorder complaining of severe depression is treated by injection of a TNF antagonist selected from the group of etanercept, infliximab, CDP 870, D2E7, or onercept in a therapeutically effective dose to the anatomic area adjacent to the spine.
[0039] In one preferred embodiment a patient with Alzheimer's Disease with dementia is treated by injection of a TNF antagonist selected from the group of etanercept, infliximab, CDP 870, D2E7, or onercept in a therapeutically effective dose to the anatomic area adjacent to the spine, with the dose repeated as a form of chronic therapy at intervals as often as twice per week to as little as once per three months.
[0040] In one preferred embodiment a patient with post-herpetic neuralgia complaining of severe persistent pain is treated by injection of a TNF antagonist selected from the group of etanercept, infliximab, CDP 870, D2E7, or onercept in a therapeutically effective dose to the anatomic area adjacent to the spine with a single dose administered 48 hours after beginning a course of antiviral medication.
[0041] In another preferred embodiment a patient with clinical depression is treated by intranasal administration of a TNF antagonist selected from the group of etanercept, infliximab, CDP 870, D2E7, or onercept in a therapeutically effective dose.
[0042] In another preferred embodiment a patient with lumbar radiculopathy due to an intervertebral disc herniation is treated by injection of a IL-1 antagonist selected from the group of IL-1 RA, Kineret, IL-1 R type 2 or IL-1 Trap in a therapeutically effective dose to the anatomic area adjacent to the involved disc.
[0043] In another preferred embodiment injection of the therapeutic molecule to the anatomic area adjacent to the spine is accomplished by interspinous injection.
[0044] In another preferred embodiment interspinous injection is accomplished by injection through the skin in the anatomic area between two adjacent spinous processes of the vertebral column.
[0045] An example of one preferred embodiment for treatment of lumbar radiculopathy due to disc herniation at the L 3-4 interspace is the perispinal administration of etanercept 25 mg by injecting through the skin of the back, between the L3 and L4 spinous processes, to deliver etanercept in anatomic proximity to the site of disc herniation.
[0046] In another preferred embodiment injection of the therapeutic molecule to the anatomic area adjacent to the disc herniation is accomplished by subcutaneous injection.
[0047] In another preferred embodiment injection of the therapeutic molecule to the anatomic area adjacent to the disc herniation is accomplished by epidural injection.
[0048] In another preferred embodiment injection of the therapeutic molecule to the anatomic area adjacent to the disc herniation is accomplished by peridural injection.
[0049] In another preferred embodiment injection of the therapeutic molecule to the anatomic area adjacent to the disc herniation is accomplished by perispinal injection.
Scientific Background:
[0050] Antibodies (immunoglobulins) are proteins produced by one class of lymphocytes (B cells) in response to specific exogenous foreign molecules (antigens). Monoclonal antibodies (mAB), identical immunoglobulin copies which recognize a single antigen, are derived from clones (identical copies) of a single B cell. This technology enables large quantities of an immunoglobulin with a specific target to be mass produced.
[0051] Monoclonal antibodies with a high affinity for a specific cytokine will tend to reduce the biologic activity of that cytokine. Substances which reduce the biologic effect of a cytokine can be described in any of the following ways: as a cytokine blocker; as a cytokine inhibitor; or as a cytokine antagonist. In this patent, the terms blocker, inhibitor, and antagonist are used interchangeably with respect to cytokines.
[0052] Advances in biotechnology have resulted in improved molecules as compared to simply using monoclonal antibodies. One such molecule is CDP 870 which, rather than being a monoclonal antibody, is a new type of molecule, that being an antibody fragment. By removing part of the antibody structure, the function of this molecule is changed so that it acts differently in the human body. Another new type of molecule, distinct from monoclonal antibodies and soluble receptors, is a fusion protein. One such example is etanercept. This molecule has a distinct function which acts differently in the human body than a simple soluble receptor or receptors.
[0053] Monoclonal antibodies, fusion proteins, and all of the specific molecules discussed above under the categories of TNF antagonists and interleukin antagonists are considered biologics, in contrast to drugs that are chemically synthesized. These biologics are derived from living sources (such as mammals (including humans), other animals, and microorganisms). The biologics mentioned above are manufactured using biotechnology, which usually involves the use of recombinant DNA technology. Cytokine antagonists are one type of biologic. Biologics are regulated through a specific division of the FDA.
[0054] Cytokine antagonists can take several forms. They may be monoclonal antibodies (defined above). They may be a monoclonal antibody fragment. They may take the form of a soluble receptor to that cytokine. Soluble receptors freely circulate in the body. When they encounter their target cytokine they bind to it, effectively inactivating the cytokine, since the cytokine is then no longer able to bind with its biologic target in the body. An even more potent antagonist consists of two soluble receptors fused together to a specific portion of an immunoglobulin molecule (Fc fragment). This produces a dimer composed of two soluble receptors which have a high affinity for the target, and a prolonged half-life. This new molecule is called a fusion protein. An example of this new type of molecule, called a fusion protein, is etanercept (Enbrel).
[0055] Tumor necrosis factor (TNF), a naturally occurring cytokine present in humans and other mammals, plays a key role in the inflammatory response, in the immune response and in the response to infection. TNF is formed by the cleavage of a precursor transmembrane protein, forming soluble molecules which aggregate in vivo to form trimolecular complexes. These complexes then bind to receptors found on a variety of cells. Binding produces an array of pro-inflammatory effects, including release of other pro-inflammatory cytokines, including IL-6, IL-8, and IL-1; release of matrix metalloproteinases; and up regulation of the expression of endothelial adhesion molecules, further amplifying the inflammatory and immune cascade by attracting leukocytes into extravascular tissues.
[0056] Interleukin-1 is a naturally occurring cytokine, present in humans and other mammals. Interleukin-1 plays a key role in the inflammatory response and in the immune response. Interleukin-1 receptor antagonist (IL-1 RA) is a naturally occurring molecule which reduces the biologic effects of interleukin-1 by interfering with the binding of IL-1 to its receptor (IL-1 R1, interleukin-1 type I receptor). Kineret (Amgen) is a recombinant form of IL-1 RA which is FDA approved for treating rheumatoid arthritis. IL-1 Receptor Type 2 (Amgen), AMG719 (Amgen), and IL-1 Trap (Regeneron), are all biologic inhibitors of interleukin-1.
[0057] Etanercept (Enbrel®, Amgen), infliximab (Remicade®), D2E7, CDP 870, and onercept are potent and selective inhibitors of TNF. D2E7, CDP 870, and onercept are in clinical development. Etanercept and infliximab are FDA approved for chronic systemic use to treat rheumatoid arthritis.
[0058] Perispinal administration and intranasal administration of cytokine antagonists are new methods of administration of the specific cytokine antagonists of consideration here. These new methods result in improved delivery of these therapeutic molecules to the nervous system, either by local diffusion; by improved transport into the cerebrospinal fluid (CSF); or by direct transport into the CNS. Improved delivery thereby enables these specific cytokine antagonists to produce therapeutic benefit for patients with a variety of neurological and neuropsychiatric disorders.
Clinical Disorders
[0059] Patients with the following clinical disorders, among others, will benefit from treatment with cytokine antagonists delivered by the perispinal route or by intranasal administration:
[0060] 1. Unipolar and Bipolar Affective Disorders
[0061] These are disorders of mood, causing recurrent depression and/or recurrent episodes of mood elevation, resulting in mania or hypomania. Current treatment regimens include the use of lithium carbonate, carbamazepine, or anti-psychotic medication. Inflammatory cytokines are involved in the regulation of sleep and mood. In the present invention, perispinal administration of TNF antagonists or IL-1 antagonists is used for the acute or chronic treatment of these disorders. Clinical experience has demonstrated the rapid beneficial effect, and the lasting beneficial effect, of this method of treatment for these disorders. Acute administration of a TNF antagonist results in rapid improvement in affect and cognitive function. Chronic administration results in decreased lability of mood, increased time intervals between mood swings, and decreased amplitude of mood swings. Chronic administration may require twice weekly dosing, but in some patients will be effective when given much less often, sometimes as little as once per three months. Some patients may only require a single dose given at the onset of a mood disturbance. Sleep improvement and improvement in cognition is noted by patients responding to treatment.
[0062] 2. Schizoaffective Illness
[0063] These patients have a thought disorder as well as a mood disorder. These patients can be difficult to distinguish from patients with pure schizophrenia or bipolar affective disorder. Most require treatment with anti-psychotic medication. Some will respond to treatment with lithium carbonate. These patients respond to treatment with the cytokine antagonists of consideration here delivered by the perispinal route. Treatment can be acute or chronic, as outlined in the discussion of unipolar and bipolar affective disorder.
[0064] 3. Schizophrenia
[0065] Schizophrenia is a thought disorder prevalent throughout the world, affecting about 1% of the world's population. Paranoid schizophrenia is a common clinical type. Treatment is almost uniformly unsuccessful. Chronic treatment with neuroleptic medication is usually required with less than satisfactory results These patients have a disturbance in cytokine patterns, which is amenable to treatment with TNF or IL-1 antagonists by perispinal administration or by intranasal administration. Treatment can be acute or chronic, as outlined in the discussion of unipolar and bipolar affective disorder.
[0066] 4. Depression
[0067] Clinical depression is characterized by depressed mood, often accompanied by additional clinical manifestations, such as sleep disturbance, weight loss, loss of appetite, apathy, anhedonia, and when severe, can be associated with suicidal ideation. It is currently treated, when indicated, with antidepressant medication, most commonly selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants. Post-partum depression can be especially serious, occurring after childbirth. Depression, even when treated, is associated with an increased suicide risk. These patients have a disturbance in cytokine patterns, which is amenable to treatment with TNF or IL-1 antagonists by perispinal administration or by intranasal administration. Clinical experience has demonstrated the rapid beneficial effect, and the lasting beneficial effect, of this method of treatment for these disorders. Treatment can be acute or chronic, as outlined in the discussion of unipolar and bipolar affective disorder.
[0068] 5. Autism
[0069] This is an incapacitating, lifelong cognitive developmental disability which usually appears in early childhood. There is no reasonably effective treatment regimen. These patients have a disturbance in cytokine patterns, which is amenable to treatment with TNF or IL-1 antagonists by perispinal administration or by intranasal administration.
[0070] 6. Anorexia Nervosa
[0071] Anorexia Nervosa is an eating disorder characterized by refusal to maintain body weight above a minimally normal weight (usually defined as 85% of expected), combined with a disturbance in the way one's weight or body shape is experienced and intense fear of gaining weight. This is associated with a disturbance in cytokine patterns, which is amenable to treatment with TNF or IL-1 antagonists by perispinal administration or by intranasal administration. Clinical experience has demonstrated weight gain as a result of the use of TNF antagonists.
[0072] 7. Obsessive-Compulsive Disorder (OCD)
[0073] OCD is an anxiety disorder characterized by persistent intrusive thoughts that can only be alleviated by patterns of rigid and ceremonial behavior. Traditional treatment may include the use of SSRIs but is often unsuccessful. These patients have a disturbance in cytokine patterns, which is amenable to treatment with TNF or IL-1 antagonists by perispinal administration or by intranasal administration.
[0074] 8. Narcotic Addiction
[0075] People attempting to discontinue the use of narcotics have great difficulty without pharmacologic assistance if they have been using the narcotics chronically at high dosage levels. Chronic narcotic use creates significant physiological changes in the CNS. These patients have a disturbance in cytokine patterns, which is amenable to treatment with TNF or IL-1 antagonists by perispinal administration or by intranasal administration.
[0076] 9. Alcohol Withdrawal
[0077] People attempting to discontinue the use of alcohol have great difficulty without pharmacologic assistance if they have been consuming large amounts of alcohol on a chronic basis. Both chronic alcohol use and alcohol withdrawal create significant physiological changes in the CNS. These patients have a disturbance in cytokine patterns, which is amenable to treatment with TNF or IL-1 antagonists by perispinal administration or by intranasal administration.
[0078] 10. Smoking Cessation/Nicotine Withdrawal
[0079] People attempting to stop smoking tobacco have great difficulty without pharmacologic assistance. Tobacco smoke contains nicotine, which, on a chronic basis, has potent biologic effects. Smoking cessation and the accompanying nicotine withdrawal creates significant physiological changes in the CNS. These patients have a disturbance in cytokine patterns, which is amenable to treatment with TNF or IL-1 antagonists by perispinal administration or by intranasal administration.
[0080] 11. Degenerative Disorders Including Parkinson's Disease, Alzheimer's Disease, Idiopathic Dementia and ALS
[0081] These chronic neurological disorders include but are not limited to Alzheimer's Disease, Pick's Disease, Creutzfeldt-Jacob Disease (CJD), Variant CJD, Parkinson's Disease, Lewy Body Disease, Idiopathic Dementia, Amyotrophic Lateral Sclerosis (ALS), and the Muscular Dystrophies. Alzheimer's Disease, Pick's Disease, CJD, Lewy Body Disease, Idiopathic Dementia and Variant CJD are all irreversible, progressive forms of dementia. ALS is a progressive motor neuron disease of unknown etiology characterized by progressive weakness. The muscular dystrophies are a group of related neuromuscular disorders which result in progressive loss of muscular function. The exact causation of all of these disorders is uncertain, and there are no curative treatment regimens currently available. Many of these disorders involve CNS, neuronal, or muscular inflammation, and many also involve accelerated neuronal apoptosis. Treatment of these disorders with TNF antagonists or IL-1 antagonists by perispinal administration and/or intranasal administration leads to clinical improvement and/or slowing of disease progression. Chronic treatment regimens are necessary, with doses usually administered at an interval varying from twice per week to once per month. Clinical experience has demonstrated the beneficial effect of this method of treatment for these disorders.
[0082] 12. Spinal Cord Injury
[0083] About 10,000 cases occur per year in the U.S., with a current population of over 200,000 patients with residual neurologic damage, many of whom are paralyzed (quadriplegia or paraplegia). Current treatment for the acute injury is inadequate. In the early 1990's it was shown that early (within 8 hours of injury) treatment with high doses of steroids (methyl prednisolone) was beneficial for some of these patients. Surgical stabilization and spinal decompression is often necessary because of excessive swelling (edema) which can itself cause further severe injury to the cord due to further compression of the cord against its bony spinal canal. The etiology of most of these cases are motor vehicle accidents, with the remainder being sports injuries, falls, and other accidents. The window of opportunity for treatment is small, since massive swelling can occur within minutes. The use of a cytokine antagonist, delivered by perispinal administration, ameliorates neurological damage caused by acute spinal cord injury, and is also beneficial for patients with chronic spinal cord injury. Treatment with TNF antagonists or IL-1 antagonists given parenterally by perispinal administration leads to clinical improvement. Clinical experience has demonstrated the beneficial effect of this method of treatment for these disorders.
[0084] 13. Headache Syndromes, including Migraine Headaches and Cluster Headaches
[0085] Elevated levels of inflammatory cytokines are found in patients with severe neurologic headache syndromes, including, but not limited to migraine headaches and cluster headaches. Migraine headaches, a form of vascular headache, are common, and may have associated neurologic symptoms, such as visual disturbance, photophobia, and, in rare instances, can be associated with stroke. Treatment of these disorders with TNF antagonists or IL-1 antagonists by perispinal administration leads to clinical improvement. Treatment regimens can be either acute or chronic, and will vary with the clinical setting. Clinical experience has demonstrated the beneficial effect of this method of treatment for these disorders, often with rapid diminution of headache pain demonstrated.
[0086] 14. Neuropathic Pain
[0087] TNF has been found to be of central importance in the pathogenesis of several types of neuropathic pain, including, but not limited to spinal radiculopathy, nerve root inflammation due to intervertebral disc herniation, and neuropathy associated with chronic constriction injury. There are many other forms of neuropathic pain, defined generally as pain initiated or caused by a primary lesion or dysfunction in the nervous system. Treatment of these disorders with TNF antagonists or IL-1 antagonists by perispinal administration leads to clinical improvement. Treatment regimens can be either acute or chronic, and will vary with the clinical setting. Clinical experience has demonstrated the beneficial effect of this method of treatment for several different forms of neuropathic pain.
[0088] 15. Lumbar and Cervical Radiculopathy
[0089] Inflammation of the nerve roots in the lumbar or cervical region may lead to neurologic dysfunction. These forms of radiculopathy commonly result in pain in a nerve root distribution, often with sensory dysfunction characterized by numbness and/or paresthesia. A smaller subset of these patients also experience motor weakness. TNF has been strongly implicated in the pathogenesis of these clinical syndromes. Release of TNF from damaged intervertebral discs, as the result of disc herniation or other forms of disc disease has been suggested to be the central causative factor. Clinical experience has established the efficacy of treatment of these disorders with TNF antagonists delivered by perispinal administration.
[0090] 16. Fibromyalgia
[0091] Fibromyalgia is a syndrome of unknown cause that results in chronic, widespread neuromuscular pain and fatigue, often with multiple, tender areas, sleep disturbance, and additional clinical symptoms. Clinical experience has established the efficacy of treatment of patients with this diagnosis utilizing TNF antagonists delivered by perispinal administration. Treatment with TNF antagonists or IL-1 antagonists given parenterally by perispinal administration leads to clinical improvement.
[0092] 17. Low Back Pain
[0093] Low back pain (LBP) can result from a wide variety of clinical conditions. Many forms of LBP are mild or spontaneously resolve. Other types are severe, treatment refractory, and can either be acute, subacute or chronic. Many of these patients have been diagnosed with intervertebral disc disease, ranging from a solitary annular tear of one disc capsule, to a mild disc bulge, to multiple large disc herniations present in a single individual. Clinical experience has established the efficacy of treatment of patients with these disc disorders through the use of TNF antagonists delivered by perispinal administration. In addition this method of treatment has been beneficial for other patients with back pain, including those patients with apparently normal MRI examination of the spine. Many of these patients may have undiagnosed annular tears of their intervertebral disc capsules, or other forms of internal disc derangement. Treatment with TNF antagonists or IL-1 antagonists given parenterally by perispinal administration leads to clinical improvement.
[0094] 18. Post-Herpetic Neuralgia
[0095] Persistent severe pain following herpes zoster can be chronic and treatment refractory, particularly with patients over the age of 65. Inflammation in the dorsal root ganglion, continuing after the healing of cutaneous lesions, has been documented. Treatment with TNF antagonists, administered by the perispinal route, in conjunction with orally administered anti-viral therapy, such as famciclovir, helps alleviate this form of neuropathic pain. Treatment with TNF antagonists or IL-1 antagonists given parenterally by perispinal administration leads to clinical improvement. Clinical experience has confirmed the beneficial effect of this treatment modality.
[0096] 19. Vertebral Disc Disease
[0097] Disease of one or more intervertebral discs can be the result of trauma, aging, arthritis, or other inflammatory disorders. The resulting damage can produce disruption of the capsule of the disc, allowing release of TNF into the extradiscal space. This may result in TNF-mediated neurotoxicity, inflammation, and resulting neuropathic pain and/or sensory and motor neuropathy or radiculopathy. These patients may have frank disc herniation, or more subtle forms of disc disruption, such as disc bulging, disc protrusion, or annular tear of the disc capsule. Many of these patients are diagnosed as having degenerative disc disease. Treatment with TNF antagonists or IL-1 antagonists given parenterally by perispinal administration leads to clinical improvement. Extensive clinical experience has documented the favorable effect of this method of treatment for patients in this clinical category.
[0098] 20. Chronic Fatigue Syndrome (CFS)
[0099] Patients with CFS have severe chronic fatigue of six months or longer duration, with known causes excluded; and have additional symptoms, including memory impairment, sore throat, adenopathy, myalgias, arthralgias, and sleep disturbance. Treatment with TNF antagonists or IL-1 antagonists by perispinal administration or intranasal administration leads to clinical improvement. Clinical experience has documented the favorable effect of this method of treatment for patients with this diagnosis.
[0100] 21. Reflex Sympathetic Dystrophy (RSD)
[0101] RSD is a chronic pain syndrome characterized by chronic, severe, treatment refractory neuropathic pain of unknown etiology, but often associated with a pre-existing injury, and often accompanied by skin and joint changes and diminished motor function in the involved extremity. Inflammatory cytokines are involved in the pathophysiology. Treatment with TNF antagonists or IL-1 antagonists given parenterally by perispinal administration leads to clinical improvement.
Dosages and Routes of Administration
[0102] The dosage of a cytokine antagonist used for perispinal administration will in general be within one order of magnitude of the dosage used as a single dose for systemic administration. For example, if the usual dose when administered systemically is 100 mg, then the dose used for perispinal administration will usually be between 10 mg and 100 mg. The exception to this general guideline occurs with intrathecal injections or intranasal administration, where the required dosage is smaller, usually in the range of 1% to 10% of the corresponding systemic dose for the intrathecal route, and usually in the range of 10% to 25% for the intranasal route.
[0103] For the treatment of acute or severe conditions, the dose will generally be adjusted upward. In the above example the dose selected would therefore be 100 mg, rather than 10 mg, if the condition were acute and/or severe.
[0104] Localized perilesional injection can allow the use of subcutaneous administration even in the case when the medication is normally administered intravenously. An example of this would be the use of infliximab subcutaneously in the interspinous area for the treatment of nerve root inflammation associated with intervertebral disc disease.
[0105] For treating the above diseases with the above mentioned TNF antagonists, these TNF antagonists may be administered by the following routes:
[0106] The above TNF antagonists may be administered subcutaneously in the human and the dosage level is in the range of 1 mg to 300 mg per dose, with dosage intervals as short as one day.
[0107] The above TNF antagonists may be administered intramuscularly in the human and the dosage level is in the range of 1 mg to 200 mg per dose, with dosage intervals as short as two days.
[0108] The above TNF antagonists may be administered epidurally in the human and the dosage level is in the range of 1 mg to 300 mg per dose, with dosage intervals as short as two days.
[0109] The above TNF antagonists may be administered peridurally in the human and the dosage level is in the range of 1 mg to 300 mg per dose, with dosage intervals as short as two days.
[0110] The above TNF antagonists may be administered by interspinous injection in the human and the dosage level is in the range of 1 mg to 300 mg per dose, with dosage intervals as short as two days.
[0111] The above TNF antagonists may be administered by intranasal administration utilizing a nasal spray or nasal inhaler in the human and the dosage level is in the range of 1 mg to 50 mg per dose, with dosage intervals as short as four hours.
[0112] Interleukin-1 antagonists are administered in a therapeutically effective dose, which will generally be 10 mg to 200 mg per dose. The dosage interval will be as short as once daily.
ADVANTAGES OF THE PRESENT INVENTION
[0113] Accordingly, an advantage of the present invention is that it provides for the localized administration of specific biologics as a new pharmacologic treatment of neurological and neuropsychiatric diseases and disorders; such that the use of these cytokine antagonists will result in the amelioration of these conditions.
[0114] Another advantage of the present invention is that it provides for specific biologics delivered by anatomically localized administration, which, when compared to systemic administration, produces one or more of the following: greater efficacy; more rapid onset; longer duration of action; improved delivery to the CNS; or fewer side effects.
[0115] Another advantage of the present invention is that it provides for specific biologics for providing suppression and inhibition of the action of cytokines in a human to treat neurological and neuropsychiatric diseases and disorders.
[0116] Another advantage of the present invention is that it provides for specific biologics administered by specific methods for treating humans with neurological and neuropsychiatric diseases and disorders which due to their biologic action will produce clinical improvement in the patient and will give the patient a better opportunity to heal, slow disease progression, prevent neurological damage, reduce pain, or otherwise improves the patient's health.
[0117] Another advantage of the present invention is that it provides for specific biologics, including cytokine antagonists to tumor necrosis factor alpha or to interleukin-1, using localized administration, including perispinal administration, as the preferred form of administration, for the treatment of neurological disorders, including dementia, low back pain, and neuropathic pain.
[0118] Another advantage of the present invention is that it provides for specific biologics, including cytokine antagonists to tumor necrosis factor alpha or to interleukin-1, using localized administration, including perispinal administration or intranasal administration, as the preferred form of delivery, for the treatment of neuropsychiatric disorders, including depression, schizophrenia, anorexia nervosa and chronic fatigue syndrome.
[0119] A latitude of modification, change, and substitution is intended in the foregoing disclosure, and in some instances, some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.
GENERAL REFERENCES
[0000]
[1]. Bathon J M, Martin R W, Fleischmann R M, et al. A comparison of etanercept and methotrexate in patients with early rheumatoid arthritis. N Engl J Med (2000); 343:1586-1593.
[2]. Mease P J, Goffe B S, Metz J, VanderStoep A, Finck B, Burge D J. Etanercept in the treatment of psoriatic arthritis and psoriasis: a randomised trial. Lancet. (2000) July 29; 356(9227):385-90.
[3]. Gorman J D, Sack K E, David J C. Treatment of ankylosing spondylitis by inhibition of tumor necrosis factor-alpha. N Engl J Med (2000); 346:1349-1356.
[4]. Moreland L W, Schiff M H, Baumgarmer S W, et al. Etanercept therapy in rheumatoid arthritis: a randomized, controlled trial. N Engl J Med (1999); 130:478-486.
[5]. Weinblatt M E, Kremer J M, Bankhurst A D, et al. A trial of etanercept, a recombinant tumor necrosis factor receptor: Fc Fusion protein, in patients with rheumatoid arthritis receiving methotrexate. N Engl J Med (1999); 340 (4):253-259.
[6]. Lovell D J, Giannini E H, Reiff A, et al. Etanercept in children with polyarticular juvenile rheumatoid arthritis. N Engl J Med (2000); 342:763-769. | A method of treating a nerve disorder mediated by nucleus pulposus in a mammal in need thereof, comprising: administering to said mammal a TNF-α inhibitor that is a monoclonal antibody which blocks TNF-α activity, thereby inhibiting TNF-α and treating said disorder. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates to aluminum brazing sheet and, more particularly, the present invention relates to high strength aluminum brazing sheet with high levels of Magnesium in the core layer and having good Controlled Atmosphere Brazing (CAB) brazeability.
BACKGROUND OF THE INVENTION
[0002] Aluminum brazing sheet is used extensively in the fabrication of heat exchangers where the light weight and high thermal conductivity of aluminum alloys provide advantages over other materials such as copper. This is particularly true for heat exchangers used in the transportation industry where weight and size are important considerations. Fabricators of these heat exchangers continue to reduce the size and weight of these units often by reducing thickness and increasing strength of the starting raw materials used to form the various components of the units. Down-gauging typically needs to be accompanied by increased post-braze strength so to not compromise the integrity of the final product. Increasing post-braze strength usually means increasing the overall amount of alloying elements (Cu, Mn, Si, Mg, etc.) in the core alloy. Magnesium (Mg) in particular is a very potent solid solution strengthening element in aluminum. Additionally, when Mg is present at high enough concentrations in combination with Silicon (Si) then it can participate in an age-hardening reaction, which can significantly increase the strength of the material.
[0003] While Mg is a tolerable and necessary element in the vacuum brazing process for aluminum, it has a very negative impact on the braze-ability of aluminum in the Controlled Atmosphere Brazing (CAB) process. The reason for the negative impact has long been recognized as due to the interference of Mg with the fluxing action of the commonly utilized CAB fluxes, as exemplified by the industry standard Nocolok® brazing flux. Consequently, the level of Mg in the core alloy of the brazing sheet is typically limited to 0.25 wt. % or lower for CAB brazing applications, and even that can result in a noticeable degradation in the brazing performance. The vacuum brazing process is an older technology and continues to be displaced by the newer CAB process. Therefore, the limitations on Mg as a strengthening element is becoming more commercially important with the current aluminum braze sheet designs and CAB process. There are CAB fluxes that are modified with Cesium that have some moderately increased tolerance for Mg, those fluxes are more expensive than standard Nocolok® and often are not acceptable for that reason. The greater use of Mg presents a clear opportunity for increasing strength with some current alloys reaching their reasonable limits for the other primary alloying elements (Mn, Si, Cu and Cr). However, the known negative impact Mg has on brazing performance is restricting that opportunity.
[0004] In addition to the known CAB brazing issues with high Mg alloys, fabrication of multi-layer composite brazing sheet alloys with high Mg layers is very challenging on a commercial level. These products are traditionally fabricated by a hot-roll bonding process. The use of high Mg layers brings with it significant problems from a bonding standpoint in the hot mill. The large difference in high temperature flow stress between Mg-bearing layers and Mg-free layers results in non-uniform metal flow and therefore difficulty in control of the thickness of the various layers through the sealing process. In addition, Mg-bearing alloys readily generate thick oxide layers at high temperatures. These oxide layers can strongly impede the bonding process between adjacent layers. The present invention resolves these fabrication problems by casting the high Mg-bearing core alloy as part of a multi-layer ingot in a multi-alloy casting process in which the high-Mg core is cast adjacent to at least one Mg-free or very low Mg-bearing interliner. That composite multi-layer ingot is then further processed in the mill via hot and cold rolling and annealing to fabricate the final product.
SUMMARY OF THE INVENTION
[0005] The present invention is embodied in claims 1 - 33 and is suitable for use with brazing flux with or without the addition of Cesium, such as NOCOLOK® brazing flux.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 an envisioned high strength tubestock material (150 to 400 microns thickness);
[0007] FIG. 2 a an envisioned “one side clad” high strength side-support or tank material (≧1 mm thickness);
[0008] FIG. 2 b an envisioned “two side clad” high, strength side-support or header material (≧1 mm thickness);
[0009] FIG. 3 is a schematic structure of a fabricated high strength tubestock material; and
[0010] FIG. 4 are plots of exemplar braze liner and inter liner thicknesses versus core Mg content.
DETAILED DESCRIPTION OF THE INVENTION
[0011] The present invention is a multi-layer brazing sheet partially or completely fabricated via a multi-alloy casting process by which the beneficial impact of Mg on post-braze strength can be realized in brazed heat exchangers while maintaining excellent CAB brazing performance with standard Nocolok® brazing flux. The present invention is a composite multi-layer brazing sheet in which a Mg-rich core layer is effectively isolated from the braze filler metal by interlayers that functionally act as diffusion barriers for the Mg during fabrication in the mill and during the braze cycle. The process starts by producing a multi-layer composite ingot in which the Mg-rich core layer is adjacent to or between essentially Mg-free interlayers (up to 0.05 wt. %). The composition and thickness of these interlayers is such that after processing the ingot to the wrought sheet product and subjecting it to the required forming and braze thermal cycle, that the Mg content of the liquid filler metal during the braze cycle does not exceed 0.10 wt. %, wherein one embodiment includes a Mg content below 0.05 wt. %.
[0012] In the present invention, core Mg levels of up to 3.0 wt. % are possible. One embodiment of a high Mg core comprised about 0.5 wt. % to 3.0 wt. % Mg. Another embodiment of a high Mg core comprises about 1.0 wt. % to about 3.0 wt. % Mg. Another embodiment of a high Mg core comprises about 1.1 wt. % Mg. Another embodiment of a high Mg core comprises about 1.5 wt. % to about 3.0 wt. % Mg. Yet another embodiment of a high Mg core comprises about 2.0 wt. % to about 3.0 wt. % Mg. Another embodiment of a high Mg core comprises about 2.5 wt. % to about 3.0 wt. % Mg. This is a significant departure from all previous brazing sheet composite materials and will result in significant increases in post-braze strength while maintaining excellent CAB braze-ability. When referring to any numerical range of values, such ranges are understood to include each and every number and/or fraction between the stated range minimum and maximum. For example, a range of about 0.5 to 3.0 wt. % would expressly include all intermediate values of 0.6, 0.7, 0.8, 0.9, and 1.0 wt. %, all the way up to and including 2.8, 2.9, and 3.0 wt. % Mg. The same applies to each other numerical property, relative thickness and/or elemental range set forth herein.
[0013] One embodiment of the present invention includes a substantially Magnesium (Mg)—free inter-liner (skin) on a high Mg core alloy whereby the control of the thickness of the skin material controls the Mg diffusion out of the core.
[0014] One aspect of the present invention is the ability to cast multi-alloy layer composite ingots with discrete layers of different alloy compositions as described below. One embodiment of the present invention employs the Simultaneous Multi-Alloy Composite casting technology disclosed in U.S. Pat. No. 6,705,384 by Kilmer et al. (incorporated herein by reference). Another embodiment of the present invention employs the Simultaneous Multi-Alloy Composite casting technology disclosed in U.S. Pat. No. 7,407,713 by Kilmer et al. (incorporated herein by reference). Another embodiment of the present invention employs the Unidirectional Solidification of Casting process disclosed in U.S. Pat. No. 7,264,038 by Men Chu et al. (incorporated herein by reference). Another embodiment of the present invention employs the Unidirectional Solidification of Casting process disclosed in U.S. Pat. No. 7,377,304 by Men Chu et al. (incorporated herein by reference). Another embodiment of the present invention employs the “Fusion” method for casting composite ingot disclosed in U.S. Pat. No. 7,472,740 by Anderson et al. (incorporated herein by reference). The invention is not limited to those multi-layer ingot casting processes sited. Any casting process that can produce a multi-layer ingot wherein at least one of the layer compositions is a high Mg-bearing alloy is envisioned to be embodied in this invention. By casting the various alloy layers in a controlled manner into one multi-layer ingot the significant aforementioned production issues associated with bonding on the hot mill are eliminated. The composite ingot of this present invention can be partially processed in the conventional manner (e.g., hot-roll/bonding). For example, the fabrication steps can include hot-roll bonding a multi-layer composite ingot cast via a multi-layer alloy casting process comprising a high-Mg core layer bounded by one or two essentially Mg-free interliner layers to one or two 4000-series braze layers in a hot roll bonding process. Alternatively that multi-layer composite ingot can be bonded to one 4000-series braze liner and a different layer (for instance a 3000-series or 7000-series alloy on the opposing side of the composite in a hot-roll bonding process. The AA4000 series braze cladding alloy can comprise up to about 2.5 wt. % Zn. Another embodiment of the AA4000 series braze cladding alloy can comprise less than 0.1 wt. % Mg. Those multi-layer composites would then be fabricated to finished product of desired gauge and temper in the traditional manner.
[0015] There can be several types of final products manufactured from the above mentioned process. One embodiment is braze sheet for tubestock, which will typically have a thickness ranging from about 150 to about 400 microns and produced in an H2X or H1X temper. The braze sheet would be constructed using a predetermined set of alloys and relative layer thicknesses to achieve the desired combination of formability, braze-ability, post-braze strength and corrosion resistance. Another embodiment of the present invention is for the manufacture of a heavier gauge product, such as for a radiator side support or a stiffener plate. The higher gauge product can utilize a different set of alloys and would generally be fabricated with a different relative layer thicknesses to optimize the product's attributes. One of the design considerations of a braze sheet is the diffusion distance of the Mg from the core layer towards the surfaces of the product during the fabrication in the mill and during the brazing cycle. As an example FIG. 4 shows the calculated thickness of the interliner needed to keep the average amount of Mg below 0.05 wt. % in the braze liner for a representative braze cycle for different core Mg contents. The example assumed an O-temper braze sheet of nominal 1 mm thickness having a range of about 0.8 to about 1.2 mm. Two different braze liner thicknesses were considered. Another consideration is the melting point (as reflected by the alloy solidus temperature) of the various layers since only the braze liners should melt during the braze cycle.
[0016] One of the final products of the present invention is tubestock. Tubestock is so thin that the high-Mg core alloy needs to be relatively thin and positioned near the mid-thickness of the tubestock. For example, radiator tubestocks are clad on the outside with a 4000 series filler alloy and to provide sufficient filler metal at the desired gauge, the clad ratio for the 4000 series liner will be in the range of about 10 to about 20% of the total thickness. The remaining 80 to 90% of the thickness would be a high Mg core and an interliner on one or both sides of the core and possibly a water side liner on the surface opposite the braze liner. One embodiment of the tubestock includes interliners and possibly a water-side liner that are Mg-free to promote good brazing especially in a folded tube configuration. For example, the first interliner situated between the filler metal and the core can be a 3000 series alloy with a composition comprising Mg up to about 0.15 wt. %, Mn up to about 1.8 wt. %, Si up to 1.2 wt. %, Cu up to 0.9 wt. %, Zn up to 2.0 wt. %, Fe up to 0.7 wt. %, and Ti for corrosion resistance up to 0.20 wt. %. The second interliner on the opposite side of the core is considered the water-side liner if there is no other layer bonded to its surface opposite the core since it will constitute the interior surface of the tube. In this case the second interliner can be a Zn-bearing alloy comprising Mn up to about 1.8 wt. % for additional strength, Si up to about 1.2 wt. %, Cu up to about 0.9 wt. %, Mg up to about 0.15 wt. %, Ti for corrosion resistance up to about 0.20 wt. %, Fe up to about 0.7 wt. %, and Zn up to about 6.0 wt. %. The core can be a 5000 series alloy with a Mg level up to approximately 3 wt. % and can contain Mn and or Cr for added strength, Si to provide the potential for age-hardening by Mg 2 Si precipitation after brazing, and up to about 0.2 wt. % Ti can be added for corrosion protection. The thickness of each of the two inter layer materials in the final product can be approximately 40 microns or thicker, preferably 50 microns or thicker. However, it need only be as thick as thick as necessary to assure that the amount of Mg that diffuses from the core to the filler metal will be limited and not interfere with CAB brazing.
[0017] The interliner alloys can be 1000-series, 3000-series, 7000-series or 8000-series alloys to provide the diffusion barrier function and corrosion resistance functions required for the final product.
[0018] FIG. 1 illustrates one embodiment of the present invention being a high strength, 4-layer tubestock having a thickness between about 150 microns to 400 microns. Another embodiment of the present invention can include a 5-layer structure which the second interlayer embodiment of the present invention can include a 5-layer structure which the second inter layer (indicated as the water-side liner in FIG. 1 ) comprising two layers instead of one layer. A 3000 series alloy layer can be adjacent to the core similar in composition to the first layer interlayer and the second layer (e.g., a water-side liner) being a Zn-bearing alloy of the type described above. For the case of folded tube applications where the inside surface of the tube becomes part of a braze joint, then the second interliner and water-side liners would be essentially Mg-free. For welded tube applications, those layers could contain intentional Mg additions up to 1.0 wt. %. The thicknesses of the layers based on a percentage of the total thickness contemplated for the 4-layer structure shown in FIG. 1 can be a braze liner between about 15 to about 20%, first interlayer between about 30 to about 40%, core between about 10 to 25%, and waterside liner between about 30 to about 40%.
[0019] The core layer illustrated in FIG. 1 can comprise between about 0.5 wt. % and about 3.0 wt. % Mg, up to about 1.5 wt. % Mn, up to about 0.8 wt. % Cu, up to about 0.7 wt. % Si, up to about 0.7 wt. % Fe, up to about 0.15 wt. % Zr, up to about 0.25 wt. % Cr, up to about 0.2 wt. % Ti, and up to about 0.25 wt. % Zn. Another embodiment of the core layer can comprise Si between, about 0.20 to about 0.70 wt. % Si. Another embodiment of the core layer can comprise Mn up to about 1.8 wt. %.
[0020] FIGS. 2A & 2B illustrate schematically another of the final products of the present invention, namely a braze sheet for high strength side support or tank material being approximately 1 mm to 4 mm in thickness, which is considered a heavy gauge. The relative thickness of the interlayers to the core alloy (in comparison to the ratios required in the tubestock products) can be reduced while still maintaining the required level of effective Mg diffusion barrier to assure excellent brazing performance. The interlayers are more typically 5% to 20% of the final product thickness or approximately 50 to 300 microns thick. The thickness of the interlayers allows for increasing the Mg content of the core layer, therefore, further increasing the post-braze strength. The thicknesses of the layers based on a percentage of the total thickness contemplated for the 4-layer structure shown in FIG. 2 a can be a braze liner between about 5 to about 15 %, two (2) interlayers each between about 5 to about 20%, and a core between about 70 to 80%. The thicknesses of the layers based on a percentage of the total thickness contemplated for the 5-layer structure shown in FIG. 2 b can be two (2) braze liners each between about 5 to about 10%, two (2) interlayers each between about 5 to about 20%, and a core between about 65 to 75%.
[0021] In FIG. 2 a the core alloy is a 5000 series alloy with up to about 3 wt. % Mg. The Mg level can be adjusted to accommodate the anticipated maximum temperature that will be experienced during the braze cycle. For example, if the anticipated maximum braze temperature is 610° C. then the Mg level in the core should be limited to approximately 2.6 wt. % to avoid partial melting of the core during brazing. The interlayer materials can be 3000 series alloys with Mn up to about 1.8 wt. %, Si up to about 1.2 wt. % for strength, Cu up to about 1 wt. % can be present in either or both interliners for strength, Ti up to about 0.20 wt. % can be present in either or both interlayers for corrosion resistance, and Zn up to about 6.0 wt. % can be present in either or both interlayers for adjusting the through thickness corrosion potentials. A braze liner on one surface provides the filler metal needed to join to the fin, header or other components of the heat exchanger. Alternatively, the interliners could be 1000-series or 7000-series alloys selected to provide the desired Mg-diffusion barrier and corrosion resistance attributes to the final product.
[0022] FIG. 2 b illustrates braze liners on both outer surfaces of the interlayers for instances where filler metal is needed at both surfaces. The elemental contents of the various layers are similar to those described for the one-side clad material except that in this case the second interliner necessarily would be essentially Mg-free.
EXAMPLE 1
[0023] Testing was performed on a laboratory fabricated 5-layer braze sheeting having a core alloy of Al-1.73 Mg-0.53 Si bonded on both surfaces with interlayers of Al-1.66 Mn-0.92 Si-0.62 Cu-0.14 Ti via a hot mill process. The other surface of the first interlayer was clad with a braze liner of AA4045. The other surface of the second interliner was clad with a water-side liner of Al-4.07 Zn-0.75 Si-0.17 Ti. FIG. 3 illustrates schematically the general aspects of the structure of the as-produced sheet having approximate layer thicknesses in terms of percentage relative to the total sheet thinkness comprising a brazing layer (11-15%), two (2) interlayers (33-35% each interlayer), a core (10-15%), and a waterside liner (5-9%). The braze sheet was processed to H24 tubestocks having 200 microns and 150 microns final thickness. The post-braze strength of these two materials after different post-braze histories are reported in Tables 1-3. The age-hardening response of the materials is evident in these results as the 14 day at room temperature and the 30 day at 90° C. tensile properties are notably higher than the properties Immediately after brazing. These samples show significant increases in strength over a typical three layer 3000 series tubestock material which has a post-braze Ultimate Tensile Strength (UTS) of approximately 140-150 MPa, Yield Strength (YS) 45-55 MPa and does not exhibit any measurable post-braze age-hardening response.
[0000]
TABLE 1
Post-braze tensile properties (immediately after brazing
Gauge of material
UTS
YS
el
200 microns
182 MPa
68.6 MPa
13.2%
150 microns
186 MPa
75.4 MPa
11.8%
[0000]
TABLE 2
Post-braze tensile properties (after 14 days at room temperature)
Gauge of material
UTS
YS
el
200 microns
200 MPa
84.5 MPa
12.8%
150 microns
203 MPa
89.5 MPa
10.8%
[0000]
TABLE 3
Post-braze tensile properties (after 30 days at 90 C.)
Gauge of material
UTS
YS
el
200 microns
234 MPa
121.4 MPa
12.9%
150 microns
235 MPa
126.9 MPa
10.4%
[0024] Brazeability of this multi-layer tubestock material, as judged by simple brazing tests including brazing bare fin to the tubestock in a laboratory braze furnace, was very good.
EXAMPLE 2
[0025] Testing was performed on laboratory fabricated O-temper 1 mm gauge 4-layer composite materials. This material was composed of nominally 6% braze liner AA4045, a first interliner nominally 120 microns thick of Alloy I/L 1, nominally 710 micron thick core layer of alloys Cl, and a second interliner, nominally 117 microns thick of Alloy I/L 2. The alloy compositions are outlined below.
[0000]
Alloy
Si
Fe
Cu
Mn
Mg
Cr
Zn
Ti
I/L 1
0.77
0.5
0.54
1.25
0.01
0
0.02
0.13
C1
0.07
0.24
0
0.03
2.44
0.11
0
0.14
I/L 2
0.28
0.52
0.11
1.1
0.03
0.02
1.45
0.02
[0026] The post-braze tensile strength of this material was measured as: 187 MPa UTS, 73 MPa YS, 20% elongation after 7 days at room temperature. Due to the low Si content of the core in this material the age hardening response is low and properties did not change significantly at room temperature over time.
[0027] In brazing evaluation for this material, the braze-ability was generally judged as very good. The one exception to that is where the sheared or cut edge of the multi-layer material is required to braze against another sheet. In this case the magnesium in the high-Mg core has a largely unimpeded ability to interfere with the action of the flux and in those instances the braze joint was not as continuous or as large as desired.
[0028] The layer thicknesses shown in FIGS. 1-3 are examples and are not intended to limit the claimed invention.
[0029] While various embodiments of the present invention have been described in detail, it is apparent that modifications and adaptations of those embodiments may 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. | The present invention relates to aluminum brazing sheet with high levels of Magnesium in the core layer and having good Controlled Atmosphere Brazing (CAB) brazeability and suitable for use with any commercially available brazing flux, including brazing flux with or without Cesium. | 2 |
FIELD OF THE INVENTION
[0001] The invention provides active, affordable, durable, and sulfur-tolerant catalysts and related precursors and processes useful in hydrogen production. The catalysts have a wide applicability. For example, in one embodiment, the invention provides sulfur-tolerant catalysts which, when used in a catalytic fuel processor, will facilitate sufficient hydrogen generation within a short period after automobile start-up to generate a relatively substantial amount of fuel cell power. Catalysts of the instant invention are made by reducing a catalyst precursor comprising a support phase impregnated with one or more elemental transition metals, wherein:
[0002] (a) the support phase is formed by dispersion of a monolayer on the surface of a high surface area alumina support; and
[0003] (b) the monolayer comprises XO n YO 2 , where (1) XO n is a redox active metal oxide and n is either 1.5, 2, 2.5, or 3 depending on the oxidation number of X, and (2) YO 2 is a redox inactive metal oxide.
BACKGROUND OF THE INVENTION
[0004] Fuel cells convert the chemical energy in fuels such as alcohols and hydrocarbons into usable electricity at efficiencies higher than those obtained by conventional thermal combustion. Such conversion is accomplished without production of pollutants such as SO n , NO n , and carbon soot. Since fuel cells operate at optimal efficiencies when H 2 is used as a fuel, there is currently a worldwide effort to develop and refine means of generating hydrogen from conventional fuels. These efforts include developing on-board automobile catalytic fuel processors that will generate hydrogen from gasoline or diesel fuel in a manner compatible with existing vehicle fuel distribution networks.
[0005] Conventionally, H 2 is produced in the chemical industry (for the manufacture of NH 3 or methanol, for example) from hydrocarbons by way of a four-stage process. First, hydrocarbon feedstock is hydrodesulfurized to less than 0.5 ppm of S using sulfided CoMo or NiMo catalysts and a ZnO. Second, the feedstock is subjected to steam reforming with excess steam at 800-1000° C. pursuant to the following (highly endothermic) reaction:
CH 4 +H 2 O→CO+3H 2
[0006] that uses Ni catalysts supported on alumina, magnesia, silica, or calcium aluminate. The H 2 and CO product of this reaction is referred to as synthesis gas. Next, the CO generated in steam reformation is subjected to a two-step, exothermic water gas shift reaction at 200-450° C. pursuant to the following reaction:
CO+H 2 O→CO 2 +H 2
[0007] that utilizes a high temperature shift reaction employing Fe-based catalysts and a low temperature shift reaction on Cu—ZnO catalysts. Finally, the CO content of the steam reforming reaction effluent is reduced to about 1 ppm by methanation according to the following reaction:
CO+3H 2 →CH 4 +H 2 O
[0008] using nickel-based catalysts or by partial oxidation (CO+0.5O 2 →CO 2 ) using Pt-based catalysts such as Pt—CeO 2 .
[0009] Alternatively, exothermic partial oxidation of alkanes or other hydrocarbon-containing feedstocks can be used to generate H 2 in a much lower ratio of H 2 to CO. Partial oxidation occurs pursuant to the following reaction, using methane as a feedstock example:
CH 4 +0.5O 2 →2H 2 +CO
CO+0.5O 2 →CO 2
[0010] The most active catalysts for steam reforming or partial oxidation of hydrocarbons usually contain nickel. However, conventional steam reforming or partial oxidation catalysts based on Ni (such as Ni—Al 2 O 3 , Ni—MgO, Ni—Ca—Al 2 O 4 , Ni—SiO 2 etc) lack sufficient activity for conversion of CO to CO 2 . Although nickel on alumina catalysts are effective for the conversion of methane to synthesis gas using molecular oxygen, such a catalyst, as well as commercial nickel-containing steam reforming, steam cracking, and partial oxidation catalysts, form coke and deactivate relatively rapidly. While transition metal catalysts, such as ruthenium on alumina, can be used to reform a hydrocarbyl compound in the presence of molecular oxygen, such transition metals are expensive.
[0011] One disadvantage of known catalysts and processes for the generation of hydrogen is that the hydrocarbon or alcohol feedstock that is used must be desulfurized to a level of less than 0.5 ppm of sulfur-containing compounds. This is because in the presence of such compounds, prior art catalysts undergo severe deactivation leading to drastic reduction in their productivity, selectivity and durability. The desulfurization of hydrocarbon feedstocks to a level of below 0.5 ppm of sulfur compounds prior to their use in hydrogen production processes such as steam reforming, autothermal reforming, water gas shift reaction and partial oxidation is expensive and increases the cost of the hydrogen generated by such processes.
[0012] Thus, there is a significant interest in improving the efficiencies and yields of processes that generate hydrogen, for example by reforming hydrocarbon feedstocks such as gasoline, diesel fuel, natural gas, or other fuel sources such as alcohol. Economically improving such efficiencies and yields calls for an affordable, durable, sulfur-tolerant, coke-resistant, highly active, and selective hydrogen generation catalyst. In particular, fuel cells require active, multi-functional catalysts that (1) can operate at lower temperatures; (2) facilitate the aforementioned hydrogen generation reactions; and (3) enable a more compact fuel processor design.
[0013] To meet the power needs of hydrogen-oxygen fuel cells, a hydrogen generation catalyst employed in a fuel processor must be able to generate H 2 from a hydrocarbon fuel containing typical quantities of sulfur compounds at acceptable rates and operating temperatures. Ideally, the catalyst must perform over extended periods of time and in a relatively short start-up time. The activity of the preferred catalyst must be such that it generates a gas sufficiently rich in hydrogen in a relatively small fuel processor. Among numerous potential applications of this catalyst, a current automotive design objective is the production, within 30 seconds of start-up, of 50 kW of fuel cell power derived from a 7 liter fuel processor. The fuel processor could be an integral packed bed catalytic reactor capable of generating, within the aforementioned start-up times, H 2 in sufficient yields, and at acceptable temperatures, to meet vehicular power requirements.
[0014] In designing a fuel processor for generation of hydrogen, the effect of catalyst type and configuration on steam reforming or partial oxidation reactor design and performance must be considered. Variation in catalyst type, volumetric density, and dispersion within a reactor bed can lead to increased pressure drop.
[0015] Ashcroft et al., Nature, Volume 352, page 225, (1991), describes the reforming of methane with carbon dioxide to form synthesis gas, a mixture of CO and hydrogen, using catalysts such as palladium, ruthenium and iridium on alumina, as well as nickel on alumina.
[0016] In U.S. Pat. No. 3,791,993, catalysts containing nickel for reforming gaseous or vaporizable liquid hydrocarbons using steam, carbon oxide, oxygen and/or air were prepared by coprecipitating a nickel salt, a magnesium salt and an aluminate to form a sludge. The sludge was then washed until substantially free of sodium and potassium, dried, and dehydrated at 300° C. to 750° C. The ultimate catalyst was formed after calcination at 850° C. to 1100° C. Examples show that compositions having a 1:1:2 or a 2:7:1 mole ratio of nickel, magnesium and aluminum, respectively, are suitable for converting naphtha to hydrogen-rich gaseous products using steam reforming.
[0017] U.S. Pat. No. 6,162,267 discloses steam reforming catalysts that include nickel with amounts of noble metal, such as cobalt, platinum, palladium, rhodium, ruthenium, iridium, and a support such as magnesia, magnesium aluminate, alumina, silica, zirconia, singly or in combination. These catalysts can be a single metal such as nickel or a noble metal supported on a refractory carrier such as magnesia, magnesium aluminate, alumina, silica, or zirconia, singly or in combination, promoted by an alkali metal such as potassium. Nickel supported on alumina and promoted by an alkali metal such as potassium is preferred.
[0018] Redox active transition metal oxides are well known as components of commercial catalysts. Such oxides are typically incorporated by impregnation on a support or co-precipitation to form a bulk catalyst. Examples are found in Catalytic Air Pollution Control, Commercial Technology, 2 nd Ed. 2002, R. M. Heck and R. J. Farrauto, John Wiley and Roh et al., Cat.Lett., Vol. 74, p. 31, 2001.
[0019] An example of a catalyst with a single component “two-dimensional” redox active metal oxide monolayer has been reported by Putna et al., Cat. Today, Vol. 50, p. 343, 1999. An example of a two-component, monolayer of metal oxide has been reported by Gampine et al., J Cat., Vol. 179, p. 315, 1998 (“Gampine”). Gampine does not disclose catalysts comprising both a redox inactive and a redox active component within a monolayer of metal oxide and does not disclose a monolayer comprised of a redox inactive and a redox active metal oxide as a component of an active catalyst phase. The TiO 2 and ZrO 2 used in the monolayer employed in Gampine's catalysts are both redox inactive metal oxides.
OBJECTS OF THE INVENTION
[0020] It is an object of the instant invention to provide improved catalysts and related precursors for use in generating hydrogen, for example by steam reforming.
[0021] It is an additional object of the instant invention to provide improved catalysts which are affordable, durable, sulfur-tolerant, coke-resistant, highly active, and selective.
[0022] It is an additional object of the instant invention to provide improved catalysts which, when used in steam reforming, can operate at lower temperatures and enable a more compact processor design.
[0023] It is an additional object of the instant invention to provide improved catalysts which meet the power needs of hydrogen-oxygen fuel cell powered units of various types by generating, at acceptable rates and operating temperatures, H 2 from various fuels including alcohol and hydrocarbon fuels containing typical quantities of sulfur compounds.
[0024] It is a further object of the instant invention to provide improved catalysts which, when used in steam reforming, perform over extended periods of time, have a relatively short start-up time and which generate a gas sufficiently rich in hydrogen using a relatively small catalyst volume.
SUMMARY OF THE INVENTION
[0025] In accordance with the above-stated objects, the present invention provides active, affordable, and durable catalysts and related precursors useful in the production of hydrogen by steam reforming even in the presence of significant quantities of sulfur and aromatic compounds. Catalysts of the instant invention are made by reducing a catalyst precursor comprising a support phase impregnated with one or more elemental transition metals, wherein:
[0026] (a) the support phase is formed by dispersion of a monolayer on the surface of a high surface area alumina support; and
[0027] (b) the monolayer comprises XO n YO 2 , where (1) XO n is a redox active metal oxide and n is either 1.5, 2, 2.5, or 3 depending on the oxidation number of X, and (2) YO 2 is a redox inactive metal oxide.
[0028] Catalyst precursors of the instant invention include precursors of the formula M-XO n —YO 2 /Al 2 O 3 , wherein:
[0029] (a) M is an elemental reduced transition metal or mixture of elemental reduced transition metals including one or more of Ni, Pd, Pt, Rh, and Ru;
[0030] (b) XO n is a redox-active metal oxide such as Mn 2 O 3 , V 2 O 5 , and CeO 2 ; and
[0031] (c) YO 2 is a redox-inactive metal oxide such as TiO 2 and ZrO 2
[0032] Representative catalysts of the instant invention include M-V 2 O 5 —ZrO 2 /Al 2 O 3 , where M is an elemental reduced transition metal or mixture of reduced transition metals including Ni, Pt, Pd, Rh and Ru. The instant invention also includes, for example, Ni—Y—V 2 O 5 —ZrO 2 /Al 2 O 3 catalysts, where Y is an elemental reduced transition metal or mixture of elemental reduced transition metals including Pd, Pt, Rh or Ru. Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 catalysts are preferred.
[0033] In a particularly preferred embodiment, catalysts and related precursors of the instant invention comprises around 10% by weight Ni and oxides of V and Zr wherein the molar ratio of V:Zr is from about 1:2 to about 1:3 and the Zr has been obtained from zirconium n-butoxide. As another example, a catalyst of the instant invention comprising 5% by weight Ru as the sole transition metal has utility in steam reforming reactions. Catalysts and related precursors of the instant invention comprised of approximately 1% or more of palladium (Pd), platinum (Pt), or rhodium (Rh) as the sole transition metal are also within the scope of the instant invention.
[0034] The invention also provides methods of making catalysts of the instant invention by reducing related precursors through contact with a (1) hydrocarbon feed in situ in a reactor (2) hydrogen gas-rich stream at a temperature of between about 300° C. to around 600° C. (3) helium gas-rich stream at a temperature of between about 400° C. to around 800° C., or (4) CO gas-rich stream at a temperature of between about 400° C. to around 800° C.
[0035] The invention also provides processes for the generation of hydrogen using the aforementioned catalysts and related precursors wherein hydrocarbons and steam are reacted under hydrogen-forming conditions in the presence of the catalysts or precursors. Catalysts of the instant invention are highly selective to hydrogen, have high productivity and durability, and generate hydrogen from hydrocarbon mixtures containing significant quantities of sulfur compounds. From an economic point of view, catalysts of the instant invention that include nickel are very attractive because they are less expensive than noble metal catalysts.
[0036] In one embodiment, catalysts of the instant invention are used in steam reforming of fuels including natural gas, gasoline, propane, diesel fuel or methanol. During steam reforming, catalysts of the instant invention produce a suitably high percentage yield of hydrogen to make them useful steam reforming catalysts. These catalysts, and processes of the instant invention employing such processes, are also useful in other applications, including ammonia and methanol production, that require a high hydrogen yield and full hydrocarbon conversion under typical reaction conditions.
[0037] Where Pt, Pd or Rh are used as the sole transition metal in a catalyst or related precursor of the instant invention, such metal is preferably present in the catalyst or related precursor in an amount in excess of about 1% by weight. A catalyst of the instant invention containing around 5% Ru as the sole transition metal has been shown to perform satisfactorily in steam reforming reactions. In a steam reforming reaction using Ru—V 2 O 5 —ZrO 2 /Al 2 O 3 catalysts of the instant invention (comprising around 5% by weight elemental Ru) at 750° C., a steam to carbon ratio of around 2.5 and about 0.375 g of catalyst, the following approximate product composition was obtained (mole percent): H 2 equals 66%, CO equals 11%, CO 2 equals 15%, and CH 4 equals 8%.
[0038] Catalysts of the instant invention facilitate hydrogen generation, for example by steam reforming of hydrocarbons or other suitable fuel sources at low water to carbon ratios, relatively low temperatures, and with minimal formation of C 2 or higher hydrocarbons or coke. The hydrocarbon or alcohol fuel source may, optionally, also contain sulfur compounds in concentrations similar to those found in conventional transportation fuels like gasoline and diesel. A catalyst composition of the instant invention containing only about 10% elemental nickel and the oxides of vanadium and zirconium is preferred as it displayed the highest activity and the greatest stability with time. The performance of this particular catalyst has proven superior to other catalysts of the instant invention that have been tested.
[0039] Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 catalysts of the instant invention have been used in the steam reforming of isooctane having 20 ppm sulfur, as well as a sample of gasoline containing 33 ppm of sulfur (California fuel). A hydrogen-rich product may also be generated by reacting catalysts of the instant invention in the presence of fuels such as methane, natural gas, liquefied petroleum gas, naphtha, propane, gasoline, kerosene, jet fuel, diesel or mixtures of these, and methanol.
[0040] The catalysts of the instant invention have proven stable even in the presence of sulfur compounds. In addition, the CO/CO 2 molar ratio obtained in steam reforming using Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 catalysts of the instant invention is less than around 1.5, unlike the higher and less desirable ratios obtained with conventional steam reforming catalysts. Without any intention to limit the scope of the instant invention, hydrogen spillover, its reverse, and strong metal support interaction (SMSI) are believed to contribute to the performance of the catalysts of the instant invention. The vanadia-zirconia layer is thought to partially cover the acidic sites of the support (alumina) and thus impede coke formation. Sulfur is, perhaps, eliminated as SO 2 by the O atoms originating from H 2 O adsorption/dissociation on V 2 O 5 —ZrO 2 . Again, these mechanistic postulates have no bearing on the scope of the instant invention
[0041] In another aspect of the claimed invention, Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 catalysts were dispersed in an integral packed bed reactor in a volumetric ratio of about 1:2 with silicon carbide to achieve total conversion of isooctane at reactor fuel space velocities as high as 80 g/g-catalyst-hour (g cat.hr).
[0042] The invention also provides a catalyst precursor or a catalyst prepared according to a process as described herein.
[0043] The invention is illustrated further in the following detailed description
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] [0044]FIG. 1 depicts a plot of steam reforming reaction product composition in which a 10% Ni—VO n —ZrO 2 /Al 2 O 3 catalyst of the instant invention is used during reforming (Results are shown for 4 values of the V:Zr ratio of the alkoxide impregnation solutions used in preparing the catalyst).
[0045] [0045]FIG. 2 depicts a plot of steam reforming reaction product composition in which a 10% Ni—VO n —ZrO 2 /Al 2 O 3 catalyst of the instant invention is used during reforming at different space velocities of the fuel (V:Zr impregnation solution ratio in the catalyst equals 1:4; steam to carbon ratio is 2.5:1 and the oven temperature is 750° C.).
[0046] [0046]FIG. 3 depicts a plot of steam reforming reaction product composition relative to water to carbon (or steam to carbon) ratio using a 10% Ni—VO n —ZrO 2 /Al 2 O 3 catalyst of the instant invention during reforming (V:Zr impregnation solution ratio in the catalyst equals 1:4).
[0047] [0047]FIG. 4 depicts a plot of steam reforming reaction product composition as a function of reactor wall temperature using a 10% Ni—VO n —ZrO 2 /Al 2 O 3 catalyst of the instant invention (V:Zr impregnation solution ratio in the catalyst equals 1:4, steam to carbon ratio is 3:1).
DETAILED DESCRIPTION OF THE INVENTION
[0048] As used herein, the following notation and terms have the following respective meanings:
[0049] Catalyst and precursor composition notation: the composition of a catalyst is described herein using the format M 1 -M 2 -M 3 /Al 2 O 3 , where “/” indicates that all materials to the left are supported on Al 2 O 3 and “-” separates the identities of the supported materials.
[0050] “Catalyst threshold limits” refers to the maximum fuel space velocity (g fuel/g cat.hr), that can be achieved while maintaining almost complete fuel conversion and without forming significant amounts of higher hydrocarbons (C 2 and above) and coke.
[0051] “Cold start operation” means the startup test conditions that involve rapid heating of the catalyst to the operating temperature followed by initiation of fuel and water flow.
[0052] “Formula-unit” means the smallest number of atoms that represent the composition of a compound.
[0053] “Fuel-space velocity” means grams of fuel passed per gram of catalyst per hour.
[0054] “Hydrocarbon feed” means a feedstock comprising compositions that may be used as fuels, e.g., a composition that can be steam-reformed to generate hydrogen. Examples of fuels include straight and branched alkyls such as methane, propane, isooctane; aromatic hydrocarbons such as toluene; oxygenated hydrocarbons including alcohols such as methanol and ethanol, ethers such as dimethyl ether and methyl tertbutyl ether, and glycols such as ethylene glycol; and hydrocarbon mixtures such as gasoline, kerosene, and diesel.
[0055] “Precursor” means a composition or compositions that can be converted through a controlled process to a final desired form, including for example a desired oxidation state. For example, “catalyst precursors” as used herein means compositions which, upon reduction through methods disclosed hereinafter, are converted to a catalytically-active form through a change in oxidation state.
[0056] “Impregnation” means transfer of a composition onto a surface, usually through dissolving a solution of the composition onto the surface. “Co-impregnation” means impregnation of a surface with a solution that contains two or more solutes.
[0057] “Monolayer” means a one formula unit-thick (“two-dimensional”) layer, e.g., of metal oxide, deposited (i.e., dispersed) on a surface. For example, a two-component monolayer of redox active and redox inactive metal oxides is deposited onto a high surface-area alumina support to form a catalyst and related precursor support phase. Monolayer formation was established in the case of VO n —ZrO 2 embodiments of the instant invention based on a combination of analyses including elemental analysis, surface area measurements, thermogravimetric measurements, and the absence of any lines characteristic of crystalline V 2 O 5 , VO 2 , V 2 O 3 , or ZrO 2 in the x-ray powder diffraction patterns of newly prepared and used samples of VO x —ZrO 2 /Al 2 O 3 based catalysts. This technique is an accepted means of establishing the monolayer or “two-dimensional” nature of deposited metal oxide (Roozeboom, et al., J Phys. Chem. 84, 2783-2791, 1980). A monolayer need not be continuous across the surface.
[0058] “Alkoxides” are compounds formed by the reaction of an alcohol and an alkali metal and have the formula A-OR, where A is the alkali metal and where R can be for example a C 1 to C 20 straight or branched chain alkyl, preferably a C 1 to C 6 alkyl. Alkoxides used in making the catalysts and related precursors of the instant invention include vanadium isopropoxide, zirconium isopropoxide, zirconium n-butoxide, and cenium isopropoxide. In the instant invention, alkoxides can be (but need not necessarily be) the source of the redox active metal oxide (in the case, e.g., of vanadium isopropoxide) and redox inactive metal oxide (in the case, e.g., of zirconium isopropoxide and zirconium n-butoxide) comprising the monolayer deposited onto the high surface area alumina support to form a catalyst and related precursor support phase.
[0059] A “redox active metal oxide” undergoes reduction and oxidation under steam reforming conditions described hereinafter. Redox active metal oxides include, but are not limited to, manganese (III) oxide (Mn 2 O 3 ), vanadium(V) oxide (V 2 O 5 ), cerium(IV) oxide (CeO 2 ), molybdenum(VI) oxide (MoO 3 ), and oxides of the lanthanides such as praseodymium (Pr), neodymium (Nd), gadolinium (Gd), and cerium (Ce).
[0060] A “redox-inactive metal oxide” is chemically inert under steam reforming conditions described hereinafter. Redox inactive metal oxides include, but are not limited to, ZrO 2 and TiO 2 .
[0061] The “impregnation solution” refers to a solution of the alkoxides used to impregnate alumina in the catalyst preparation producing the redox active metal oxide and the redox inactive metal oxide. This solution can contain different ratios of the alkoxides but this ratio does not define the actual ratio of the metals in the two dimensional film of the prepared catalyst.
[0062] “Skin temperature” and “quartz reactor wall temperature” mean the temperature of the outside of the quartz reactor wall.
[0063] “Sulfur-tolerant” when used herein to describe a catalyst means that the catalyst does not loose its effectiveness as the result of chemical interaction with sulfur-containing compounds in a hydrocarbon feed.
[0064] “Transition metals” (referred to herein on occasion as “M”) include but are not limited to nickel (Ni), palladium (Pd), platinum (Pt), ruthenium (Ru) and rhodium (Rh). “Elemental transition metals” means transition metals that exist in the 0 oxidation state.
[0065] “Impregnable metallic solution” as used herein means soluble compositions comprising transition metal compounds dissolved in a solvent. The transition metal compound dissolved in the impregnable metal solvent is converted to its elemental state by solvent removal followed by reduction with hydrogen. Dissolution of the impregnable metallic compound in a solvent followed by addition to the alumina supported two-component monolayer of redox active and redox inactive metal oxide deposits the elemental transition metal compound onto the monolayer. Impregnable metallic compound solvents comprise solvents such as water, tetrahydrofuran, diethyl ether, toluene, and dimethylsulfoxide. More than one transition metal compound dissolved in a solvent is used to impregnate the support in sequential operations to impregnate transition metal mixtures.
[0066] “Steam reforming” is a chemical reaction in which a fuel reacts with water to generate hydrogen and carbon oxides. Steam reforming reactions have been described above and examples of such reactions are provided hereinafter.
[0067] Catalyst precursors of the instant invention are made by impregnating a support phase with one or more elemental transition metals, wherein:
[0068] (a) the support phase is formed by dispersion of a monolayer on the surface of a high surface area alumina support; and
[0069] (b) the monolayer comprises XO n YO 2 , where (1) XO n is a redox active metal oxide and n is either 1.5, 2, 2.5, or 3 depending on the oxidation number of X, and (2) YO 2 is a redox inactive metal oxide.
[0070] Thus, the invention provides an article comprising one or more transition metals impregnated in a support phase that comprises 1) a monolayer comprising XO n YO 2 , and 2) an alumina support, wherein XO n is a redox active metal oxide, n is 1.5, 2, 2.5, or 3 depending on the oxidation number of X, and YO 2 is a redox inactive metal oxide.
[0071] In a preferred embodiment, catalysts and related precursors of the instant invention are made as follows. A boiling solution of zirconium n-butoxide and vanadium isopropoxide is deposited onto a high surface area alumina support. The resulting material is processed to form a two-component monolayer of redox active V 2 O 5 and redox inactive ZrO 2 on the alumina support. The processing entails removal of solvent by vacuum, followed by passage of water vapor for 24 hours, followed by calcining at 500° C. The resultant two-component monolayer film of redox active V 2 O 5 and redox inactive ZrO 2 on the alumina support is called the support phase. Ni is impregnated into the support having a monolayer film through dissolution of an impregnable metal compound solution comprising NiNO 3 .6H 2 O dissolved in THF and acidified with HNO 3 (pH=0.2 to 0.4) to complete formation of the catalyst precursor. The precursor is then reduced by one or more of the methods described previously to complete formation of the active, sulfur-tolerant catalyst. The ratio of V to Zr in the solution used to impregnate alumina ranges from approximately 2:1 to approximately 1:15 on a molar basis; a value of around 1:4 is particularly preferred. These preferred catalysts and related precursors can have (1) a surface area of about 200 to 250 m 2 (2) a pore volume of about 0.50 to 0.75 cm 3 per gram, and (3) an average pore diameter of about 6 to 9 nanometers. Typically, the alumina support is in the form of a spherically-shaped granule. These preferred characteristics and values are discussed further hereinafter.
[0072] Catalyst formulations of the instant invention were varied to achieve different mole ratios of V:Zr in the two component monolayer of redox active and redox inactive metal oxides. This was accomplished by using impregnation solutions with V:Zr ratios of 2:1, 1:1, 1:2, 1:3, 1:4. However, the molar ratio of V:Zr in the impregnation solution can range from about 2:1 to around 1:15 or higher. The weight percentage of the preferred transition metal Ni was also varied between about 0%, 1%, 5%, 10% and 15% by weight of the total catalyst. As shown in FIG. 2, a catalyst comprising 10% nickel, prepared using an impregnation solution with a V:Zr molar ratio of of 1:4, which was made using zirconium n-butoxide, achieved complete conversion of isooctane during steam reforming without the formation of higher hydrocarbons or coke. Fuel space velocities of as high as 80 g fuel/g cat.hr were obtained at a water to carbon ratio of 2.5:1 and at a quartz reactor wall, or skin temperature, below 715° C. At the same fuel space velocity and a skin temperature of 670° C., small amounts of unconverted isooctane and higher hydrocarbons were detected, but these were present in an amount of 0.1% on a weight basis of total gas products. Importantly, these results were obtained during a cold start operation. That is, after passing air for around eight hours at temperatures up to 200° C., the catalyst was used at the indicated fuel-space velocity immediately after the steam-reforming reactor reached operating temperature.
[0073] The steam reforming yield of hydrogen obtained by use of these preferred catalysts remained at approximately 70% by volume notwithstanding variation of V:Zr molar ratios, the weight percentage of Ni, and the use of a steam to carbon ratio in the range 2-3:1. However, as shown in FIG. 1, it was observed that a catalyst prepared with an impregnation solution having a V:Zr mole ratio of 1:4 yielded a CO/CO 2 ratio of approximately 0.6, whereas a catalyst prepared with an impregnation solution having a V:Zr mole ratio of 1:2 yielded a CO/CO 2 ratio of 1.4 and a catalyst prepared with an impregnation solution having a V:Zr mole ratio of 2:1 yielded a CO/CO 2 ratio of 1.6. Without any intent to be bound by theory or to otherwise limit the scope of the instant invention, it is believed that ZrO 2 acts as a spacer between VO n formula units in the monolayer with the result that larger amounts of ZrO 2 stabilize VO n . The presence of a relatively large amount of ZrO 2 interspersed with VO n may lower the mobility of the vanadium oxide formula units and lead to a more stable dispersion with a higher fraction of active surface sites.
[0074] Variation of the deposition sequence of the oxides of V and Zr onto the alumina confirmed the importance of the mixed monolayer dispersion of V 2 O 5 and ZrO 2 . In one experiment, a ZrO 2 layer was deposited onto an alumina support followed by deposition of a V 2 O 5 layer (prepared with an impregnation solution having V:Zr ratio of 1:1). However, this catalyst, although initially active, deactivated quite rapidly.
[0075] Using a catalyst prepared with an impregnation solution having a V:Zr ratio of 1:2 prepared from zirconium n-butoxide in place of zirconium isopropoxide resulted in a steam reforming product composition having a lower ratio of CO/CO 2 . Both of these catalysts, however, resulted in reforming H 2 yields in excess of 65%. Other zirconium alkoxides such as ethoxide or t-butoxide could be used in the preparation of the mixed oxide film.
[0076] The water to carbon, or steam to carbon, ratio during steam reforming was also varied to assess performance of the catalysts. Although the standard water to carbon ratio of reactants for steam reforming reaction used was 3.0, a lower ratio is desired. Theoretically, the stoichiometric ratio of water to carbon for the steam reforming of octane to produce H 2 and CO is 1.0. It would be expected that higher amounts of water should increase the formation of CO 2 and thus reduce the amount of CO in the product. Experiments on steam reforming reactions using a Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 catalyst (prepared with an impregnation solution having V:Zr mole ratio=1:4; Zr from zirconium n-butoxide) with variation of water to carbon ratio from 3:1 to 2:1 were conducted. Plots of the average product composition as a function of water to carbon ratio are displayed in FIG. 3. In contrast to observations at low space velocity where the product composition is not affected by the change of water to carbon ratio between 3:1 and 2:1, with increasing fuel space velocity there is a gradual increase in the CO/CO 2 ratio.
[0077] Variations in reactor fuel-space velocity indicate that there are preferred catalyst configurations in packed bed reactors employing the catalysts of the instant invention. Slow heat transfer to and from the reactor bed and a large pressure drop across the bed were not problematic at a low fuel space velocity (e.g., 2.5 g fuel/g cat.hr or less). However, with a typical catalyst bed configuration (3 g catalyst forming 11.5 cm packed-bed contained in a 0.75 cm ID quartz column), reactions at a fuel space velocity of 18 g/g cat.hr created a large temperature gradient between the reactor wall and the bed center. This large temperature gradient, which was sometimes as high as 100° C., was due to the large amount of heat taken by the endothermic steam reforming reaction. At oven set-temperatures of 750° C., the front end of the bed was found to be as low as 450° C. while the reactor wall temperature was around 550° C. As indicated by the data in FIG. 4, there is a slight rise in the amount of hydrogen production going from 700° C. to 800° C. but the CO/CO 2 ratio is not influenced. Methane production decreases with increasing temperature.
[0078] Very good performance was observed using a catalyst bed configuration that employed a mixture of catalyst and silicon carbide in a 1:2 volume ratio. With this reactor configuration, during steam reforming at fuel space velocities as high as 18 grams of fuel/g cat.hr, the temperature difference between reactor wall and the center of the bed can be as low as 10° C.
[0079] Catalyst threshold limits in the operation using the packed-bed reactor system of the instant invention were also determined. Experiments to determine the threshold limit of the catalyst show that the Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 (V:Zr mole ratio=1:4; Zr obtained from zirconium n-butoxide) catalyst formulation can undergo steam reforming reaction at fuel space velocity of 80 g/g cat.hr at water to carbon ratio of 2.5 resulting in 100% fuel conversion without any formation of higher hydrocarbons or coke. It was observed also that the reactions at these space velocities gave a product selectivity of around 70% H 2 and a CO/CO 2 ratio of no greater than 1.5. This CO/CO 2 ratio suggests that the catalyst is also enhancing the high temperature water gas shift reaction. While the H 2 production is unchanged at high space velocities, the CO/CO 2 ratio is significantly increased. Furthermore, the catalyst was able to perform well in cold-start operations involving using the catalyst for reaction at high fuel space velocities immediately after the reactor reached operating temperature. The fuel space velocities obtained thus far indicate that the catalyst threshold limit has not been reached.
[0080] The invention is further described in the following examples, which are illustrative and not limiting. All percentages are weight percentages, unless otherwise specified.
EXAMPLE 1
Preparation of Catalyst Support Phase
[0081] Alumina from Norton Chemical Company was supplied as spherically-shaped granules. These were either used as spherically-shaped granules or crushed and sieved to 40/60 mesh. Vanadium(V) isopropoxide (98%), and zirconium(W) isopropoxide isopropanol (99.9%) complex were purchased from Aldrich. These materials were kept in a nitrogen-filled atmosphere prior to use. Ruthenium(III) acetylacetonate, rhodium(III) acetylacetonate, palladium(II) acetylacetonate, platinum(II) acetylacetonate and nickel(II) nitrate were purchased from Strem. HPLC grade THF from Fisher Scientific was used after being dried over potassium by distillation. The gases hydrogen, nitrogen, helium, argon, and air, purchased from Air Products, were purified by in-line gas dryers and oxygen scavengers. Air was purified using in-line moisture scavengers.
[0082] The preparation of the oxide support involved reaction of the metal oxide monolayer precursors, metal alkoxides, with the surface hydroxyl groups of the supporting oxide under controlled conditions in order to achieve monolayer dispersions. The alumina was dried at 110° C. to remove any physisorbed water, leaving the surface hydroxylated. In a typical preparation of the V 2 O 5 —ZrO 2 /Al 2 O 3 catalyst support, vanadium isopropoxide and zirconium isopropoxide, taken in a 1:1 mole ratio and the amount required to react with all the surface hydroxyl groups, were dissolved in 15 mL of dry THF. The alkoxide solution was heated to boiling and kept under reflux for 1 hour. Then the alumina was impregnated with the hot alkoxide solution and heating was continued for 24 hours. The excess solvent along with small amounts of unreacted alkoxides was removed followed by washing with THF. The remaining solid residue was slowly hydrolyzed by passing water vapor in a nitrogen carrier for 24 hours at 80° C. At the end of the hydrolysis period the material was calcined at 500° C. to yield the final support. Other supports prepared using other zirconium alkoxides were prepared in the same manner.
EXAMPLE 2
Preparation of Catalyst Precursors
[0083] To prepare around 22 g of Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 catalyst precursor containing 10% Ni, 9.91 g of NiNO 3 .6H 2 O is dissolved in THF and acidified with HNO 3 (pH=0.2 to 0.4) and stirred overnight. To this is added 20 g of V 2 O 5 —ZrO 2 /Al 2 O 3 that has been treated in vacuum overnight at 10° C. After stirring for 24 hours, the solvent is removed by evaporation in air. It is then dried in an oven at 110° C. for 4 hours and then calcined at 600° C.
[0084] For catalysts comprised of Pd, Pt or Rh alone, at least around 1% by weight of such transition metals should typically be used. For catalysts containing Ni in combination with other transition metals, mixtures of 10% elemental Ni with at least 1% of one or more of the other elemental transition metals should be preferred. For 1 g of V 2 O 5 —ZrO 2 /Al 2 O 3 catalyst containing 1% Pt, around 0.021 g of platinum(III) acetylacetonate precursor is dissolved in 8 mL of THF and acidified with HNO 3 (pH=0.2 to 0.4) and stirred overnight. It is then dried in an oven at 110° C. for 4 hours and then calcined at 600° C.
EXAMPLE 3
Catalyst Screening
(a) Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 Catalysts
[0085] In this and the following examples, all catalysts tested or described were, or would be, in the form of 40-60 mesh particles unless otherwise noted. Reactant feed was controlled with mass flow controllers or syringe pumps. The product stream was analyzed using gas chromatography.
[0086] Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 catalysts, prepared from catalyst precursors and characterized as described in Examples 1 and 2 were screened by measuring catalytic activities using an integral packed bed reactor. The catalyst support alumina was also tested as were compositions containing only one of Ni, Pd, Pt, Ru or Rh supported on alumina. While these were catalytically active initially, they deactivated quickly during testing. Similarly, catalyst compositions comprising an elemental transition group metal, e.g., Ni, Pd, Pt, Ru or Rh supported on inert supports such as alumina were tested and were catalytically active initially, but soon deactivated. Samples containing the oxides of vanadium and zirconium supported on alumina exhibited high hydrogen generation catalytic activity when contacted with hydrocarbons and steam but also rapidly deactivated. 10% Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 (Ni is elemental Ni) catalysts displayed the highest activity and the greatest stability with time.
(b) Catalytic Activity (Nickel-Containing Catalysts)
[0087] Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 catalysts of the instant invention were calcined for 5 hours and reduced for 12 hours at 600° C. prior to reaction. They showed a remarkable reactivity and longevity. In a typical steam reforming run using such compositions comprising 10% elemental Ni at 750° C., a steam to carbon ratio of 2.5 and 0.375 g of catalyst, the following product composition at a time on stream of 100 hours was obtained (mole percent): H 2 =70%, CO=15%, CO 2 =10% and CH 4 =3%. No significant loss in activity was observed after 200 hours of operation and no carbon deposition occurred on the catalyst particles. The only reaction products generated throughout the run were H 2 , CO 2 , CO and CH 4 ; no higher hydrocarbons were generated. Repeated studies indicate that a combination of all three components, namely, the transition group metal and the oxides of vanadium and zirconium are essential for high catalytic activity.
EXAMPLE 4
Catalysts with Other Metals
[0088] Catalysts containing 1% Pd, Pt, Ru, and Rh, supported on V 2 O 5 —ZrO 2 /Al 2 O 3 were also studied. Their oxides, generated by calcining the impregnated precursors, are all easily reducible (typically done at 350° C. for ten hours under hydrogen flow). When these metals are supported on alumina (without the presence of the oxides of vanadium and zirconium) the catalysts exhibit high initial activity and selectivity toward H 2 in steam reforming of isooctane, but generally deactivated quickly due to formation of coke on their surface. Increasing the amount of such transition metals to 10% by weight should yield catalysts with a prolonged activity just as was observed when nickel content was increased from 1% to 10%.
EXAMPLE 5
Catalysts with TiO) as the Redox Inactive Metal Oxide Component
[0089] A catalyst prepared using titania, TiO 2 , in place of ZrO 2 , Ni(10%)-V 2 O 5 —TiO 2 /Al 2 O 3 , was tested using both isooctane and methane as fuels. With isooctane a space velocity threshold limit of 52 g/g cat.hr was observed at an oven set temperature of 775° C. and a reactor skin temperature of 715° C. With methane a threshold of 26 g/g cat.hr was observed at an oven set temperature of 775° C. and a reactor skin temperature of 715° C.
EXAMPLE 6
Catalyst With a Lanthanide Oxide as the Redox-Active Metal Oxide: Ni(10%)-CeO 2 —ZrO 2 /Al 2 O 3
[0090] A catalyst prepared using ceria, CeO 2 , in place of V 2 O 5 , Ni (10%)-CeO 2 —ZrO 2 /Al 2 O 3 , was tested using isooctane as fuel. A space velocity threshold limit of 43 g/gcat.hr was observed at an oven set temperature of 750° C. and a reactor skin temperature of 715° C.
EXAMPLE 7
Catalyst Test with California Fuel
[0091] The Ni(10%)-V 2 O 5 —ZrO 2 /Al 2 O 3 (40-60 mesh) catalyst was tested using the California fuel. This fuel contains a blend of 26.3% aromatic compounds, 5.9% olefins, 67.8% saturates, and also 33 ppm of sulfur. The catalyst was able to convert the fuel entirely to H 2 , CO, CO 2 , and CH 4 at an oven set temperature of 750° C. During 5 days of operation, there was no catalyst deactivation, coke formation was not detected, and high H 2 selectivity and a ratio of CO 2 /CO of greater than 1 was achieved. A typical composition of the product reformate (product of the steam reforming reaction) (on H 2 O and N 2 -free basis) comprised H 2 (66.2%) ;CO (8.4%) ;CO 2 (25.2%) and CH 4 (0.2%).
EXAMPLE 8
Ru Catalysts
[0092] Ru—V 2 O 5 —ZrO 2 /Al 2 O 3 catalysts of the instant invention were calcined for around 5 hours and reduced at 12 hours at around 600° C. prior to reaction. In a typical steam reforming run using such compositions comprising 5% by weight elemental Ru at 750° C. a steam to carbon ratio of 2.5 and 0.375 g of catalyst, the following product composition was obtained (mole percent): H 2 =66%, CO=11%, CO 2 =15% and CH 4 =8%. The maximum space velocity attained without appearance of more than 2% C 2 or C 3 was 24 g fuel/g cat.hr.
EXAMPLE 9
Demonstration of Redox Activity of the Metal Oxide Monolayer
[0093] A Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 catalyst, comprised of vanadium in an initial (V) oxidation state, after reduction in a hydrogen stream to produce V 2 O 3 (black), was observed to react with water vapor to generate a blue colored material consistent with the color of VO 2 . This observation is evidence for the water oxidation of V(III),to V(IV) in the solid state. The redox activity of the vanadium component of this catalyst is established by this observation. A X-ray photoelectron spectroscopy study of a used sample of the catalyst established the presence of vanadium in oxidation states V, IV, and III. | The invention provides active, affordable, durable, and sulfur-tolerant catalysts and related precursors and processes useful in hydrogen production. The catalysts have a wide applicability. For example, in one embodiment, the invention provides sulfur-tolerant catalysts which, when used in a catalytic fuel processor, will facilitate sufficient hydrogen generation within 30 seconds or so of automobile start-up to generate around 50 kW of fuel cell power. Catalysts of the instant invention are made by reducing a catalyst precursor comprising a support phase impregnated with one or more elemental transition metals, wherein:
(a) the support phase is formed by dispersion of a monolayer on the surface of a high surface area alumina support; and
(b) the monolayer comprises XO n YO 2 , where (1) XO n is a redox active metal oxide and n is either 1.5, 2, or 2.5 depending on the oxidation number of X, and (2) YO 2 is a redox inactive metal oxide.
Ni—V 2 O 5 —ZrO 2 /Al 2 O 3 catalysts of the instant invention are preferred. | 8 |
CLAIM OF PRIORITY UNDER 35 U.S.C. §119
[0001] The present application for patent claims priority to Provisional Application No. 60/830,735 entitled “METHOD AND APPARATUS FOR CONTINUOUS ASSESSMENT OF A CARDIOVASCULAR PARAMETER USING THE ARTERIAL PULSE PRESSURE PROPAGATION TIME AND WAVEFORM,” filed Jul. 13, 2006, and assigned to the assignee hereof and hereby expressly incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The invention relates generally to a system and method for hemodynamic monitoring. More particularly, the invention relates to a system and method for estimation of at least one cardiovascular parameter, such as vascular tone, arterial compliance or resistance, stroke volume (SV), cardiac output (CO), etc., of an individual using a measurement of an arterial pulse pressure propagation time and a waveform.
DESCRIPTION OF THE RELATED ART
[0003] Cardiac output (CO) is an important indicator not only for diagnosis of disease, but also for continuous monitoring of the condition of both human and animal subjects, including patients. Few hospitals are therefore without some form of conventional equipment to monitor cardiac output.
[0004] One way to measure CO is using the well-known formula:
[0000] CO=HR*SV, (Equation 1)
[0000] where SV represents the stroke volume and HR represents the heart rate. The SV is typically measured in liters and the HR is typically measured in beats per minute, although other units of volume and time may be used. Equation 1 expresses that the amount of blood the heart pumps out over a unit of time (such as a minute) is equal to the amount it pumps out on every beat (stroke) times the number of beats per time unit.
[0005] Since the HR is easy to measure using a wide variety of instruments, the calculation of CO usually depends on some technique for estimating the SV. Conversely, any method that directly yields a value for CO can be used to determine the SV by dividing by the HR. Estimates of CO or SV can then be used to estimate, or contribute to estimating, any parameter that can be derived from either of these values.
[0006] One invasive method to determine CO (or equivalently SV) is to mount a flow-measuring device on a catheter, and then to thread the catheter into the subject and to maneuver it so that the device is in or near the subject's heart. Some such flow-measuring devices inject either a bolus of material or energy (usually heat) at an upstream position, such as in the right atrium, and determine flow based on the characteristics of the injected material or energy at a downstream position, such as in the pulmonary artery. Patents that disclose implementations of such invasive techniques (in particular, thermodilution) include:
[0007] U.S. Pat. No. 4,236,527 (Newbower et al., 2 Dec. 1980);
[0008] U.S. Pat. No. 4,507,974 (Yelderman, 2 Apr. 1985);
[0009] U.S. Pat. No. 5,146,414 (McKown et al., 8 Sep. 1992); and
[0010] U.S. Pat. No. 5,687,733 (McKown et al., 18 Nov. 1997).
[0011] Still other invasive devices are based on the known Fick technique, according to which CO is calculated as a function of oxygenation of arterial and mixed venous blood. In most cases, oxygenation is sensed using right-heart catheterization. There have, however, also been proposals for systems that non-invasively measure arterial and venous oxygenation, in particular, using multiple wavelengths of light; but to date they have not been accurate enough to allow for satisfactory CO measurements on actual patients.
[0012] Invasive methods have obvious disadvantages. One such disadvantage is that the catheterization of the heart is potentially dangerous, especially considering that the subjects (especially intensive care patients) on which it is performed are often already in the hospital because of some actually or potentially serious condition. Invasive methods also have less obvious disadvantages. One such disadvantage is that thermo-dilution relies on assumptions such as uniform dispersion of the injected heat that affects the accuracy of the measurements depending on how well they are fulfilled. Moreover, the introduction of an instrument into the blood flow may affect the value (for example, flow rate) that the instrument measures. Therefore, there has been a long-standing need for a method of determining CO that is both non-invasive (or at least as minimally invasive as possible) and accurate.
[0013] One blood characteristic that has proven particularly promising for accurately determining CO less invasively or non-invasively is blood pressure. Most known blood pressure based systems rely on the pulse contour method (PCM), which calculates an estimate of CO from characteristics of the beat-to-beat arterial pressure waveform. In the PCM, “Windkessel” (German for “air chamber”) parameters (characteristic impedance of the aorta, compliance, and total peripheral resistance) are used to construct a linear or non-linear hemodynamic model of the aorta. In essence, blood flow is analogized to a flow of electrical current in a circuit in which an impedance is in series with a parallel-connected resistance and capacitance (compliance).
[0014] The three required parameters of the model are usually determined either empirically, through a complex calibration process, or from compiled “anthropometric” data, that is, data about the age, sex, height, weight, etc., of other patients or test subjects. U.S. Pat. No. 5,400,793 (Wesseling, 28 Mar. 1995) and U.S. Pat. No. 5,535,753 (Petrucelli et al., 16 Jul. 1996) are representative of systems that utilize a Windkessel circuit model to determine CO.
[0015] Many extensions to the simple two-element Windkessel model have been proposed in hopes of better accuracy. One such extension was developed by the Swiss physiologists Broemser and Ranke in their 1930 article “Ueber die Messung des Schlagvolumens des Herzens auf unblutigem Wegf,” Zeitung für Biologie 90 (1930) 467-507. In essence, the Broemser model—also known as a three-element Windkessel model—adds a third element to the basic two-element Windkessel model to simulate resistance to blood flow due to the aortic or pulmonary valve.
[0016] PCM systems can monitor CO more or less continuously, without the need for a catheter to be left in the patient. Indeed, some PCM systems operate using blood pressure measurements taken using a finger cuff. One drawback of PCM systems, however, is that they are no more accurate than the rather simple, three-parameter model from which they are derived; in general, a model of a much higher order would be needed to accurately account for other phenomena, such as the complex pattern of pressure wave reflections due to multiple impedance mis-matches caused by, for example, arterial branching. Other improvements have therefore been proposed, with varying degrees of complexity.
[0017] The “Method and Apparatus for Measuring Cardiac Output” disclosed by Salvatore Romano in U.S. Pat. No. 6,758,822, for example, represents a different attempt to improve upon PCM methods by estimating the SV, either invasively or non-invasively, as a function of the ratio between the area under the entire pressure curve and a linear combination of various components of impedance. In attempting to account for pressure reflections, the Romano system relies not only on accurate estimates of inherently noisy derivatives of the pressure function, but also on a series of empirically determined, numerical adjustments to a mean pressure value.
[0018] At the core of several methods for estimating CO is an expression of the form:
[0000] CO=HR *( K*SV est ) (Equation 2)
[0000] where HR is the heart rate, SV est is the estimated stroke volume, and K is a scaling factor related to arterial compliance. Romano and Petrucelli, for example, rely on this expression, as do the apparatuses disclosed in U.S. Pat. No. 6,071,244 (Band et al., 6 Jun. 2000) and U.S. Pat. No. 6,348,038 (Band et al., 19 Feb. 2002).
[0019] Another expression often used to determines CO is:
[0000] CO=MAP*C/tau (Equation 3)
[0000] where MAP is mean arterial pressure, tau is an exponential pressure decay constant, and C, like K, is a scaling factor related to arterial compliance K. U.S. Pat. No. 6,485,431 (Campbell, 26 Nov. 2002) discloses an apparatus that uses such an expression.
[0020] The accuracy of these methods may depend on how the scaling factors K and C are determined. In other words, an accurate estimate of compliance (or of some other value functionally related to compliance) may be required. For example, Langwouters (“The Static Elastic Properties of 45 Human Thoracic and 20 Abdominal Aortas in vitro and the Parameters of a New Model,” J. Biomechanics, Vol. 17, No. 6, pp. 425-435, 1984) discusses the measurement of vascular compliance per unit length in human aortas and relates it to a patient's age and sex. An aortic length is determined to be proportional to a patient's weight and height. A nomogram, based on this patient information, is then derived and used in conjunction with information derived from an arterial pressure waveform to improve an estimate of the compliance factor.
[0021] It is likely that the different prior art apparatuses identified above, each suffer from one or more drawbacks. The Band apparatus, for example, requires an external calibration using an independent measure of CO to determine a vascular impedance-related factor that is then used in CO calculations. U.S. Pat. No. 6,315,735 (Joeken et al., 13 Nov. 2001) describes another device with the same shortcoming.
[0022] Wesseling (U.S. Pat. No. 5,400,793, 28 Mar. 1995) attempts to determine a vascular compliance-related factor from anthropometric data such as a patient's height, weight, sex, age, etc. This method relies on a relationship that is determined from human nominal measurements and may not apply robustly to a wide range of patients.
[0023] Romano attempts to determine a vascular impedance-related factor solely from features of the arterial pressure waveform, and thus fails to take advantage of known relationships between patient characteristics and compliance. In other words, by freeing his system of a need for anthropometric data, Romano also loses the information contained in such data. Moreover, Romano bases several intermediate calculations on values of the derivatives of the pressure waveform. As is well known, however, such estimates of derivatives are inherently noisy. Romano's method has, consequently, been unreliable.
[0024] What is needed is a system and method for more accurately and robustly estimating cardiovascular parameters such as arterial compliance (K or C) or resistance, vascular tone, tau, or values computed from these parameters, such as the SV and the CO.
[0025] One of the present inventors earlier published that the SV can be approximated as being proportional to the standard deviation of the arterial pressure waveform P(t), or of some other signal that itself is proportional to P(t): U.S. Published Patent Application No. 2005/0124903 A1 (Luchy Roteliuk et al., 9 Jun. 2005, “Pressure based System and Method for Determining Cardiac Stroke Volume”). Thus, one way to estimate the SV is to apply the relationship:
[0000] SV=K σ( P )= Kstd ( P ) (Equation 4)
[0026] where K is a scaling factor and from which follows:
[0000] CO=K σ( P ) HR=Kstd ( P ) HR (Equation 5)
[0027] This proportionality between the SV and the standard deviation of the arterial pressure waveform is based on the observation that the pulsatility of a pressure waveform is created by the cardiac SV into the arterial tree as a function of the vascular tone (i.e., vascular compliance and peripheral resistance). The scaling factor K of equations 4 and 5 is an estimate of the vascular tone.
[0028] Recently, one of the present inventors also published that vascular tone can be reliably estimated using the shape characteristics of the arterial pulse pressure waveform in combination with a measure of the pressure dependant vascular compliance and the patient's anthropometric data such as age, gender, height, weight and body surface area (BSA): U.S. Published Patent No. 2005/0124904 A1 (Luchy Roteliuk, 9 Jun. 2005, “Arterial pressure-based automatic determination of a cardiovascular parameter”). To quantify the shape information of the arterial pulse pressure waveform, he used higher order time domain statistical moments of the arterial pulse pressure waveform (such as kurtosis and skewness) in addition to the newly derived pressure weighted statistical moments. Thus, the vascular tone is computed as a function of a combination of parameters using a multivariate regression model with the following general form:
[0000] K =χ(μ T1 , μ T2 , . . . μ Tk , μ P1 , μ P2 , . . . μ Pk , C ( P ), BSA , Age, G . . . ) (Equation 6)
[0000] where
K is vascular tone (the calibration factor in equations 4 and 5);
X is a multiregression statistical model;
μ 1T . . . μ kT are the 1-st to k-th order time domain statistical moments of the arterial pulse pressure waveform;
μ 1P . . . μ kP are the 1-st to k-th order pressure weighted statistical moments of the arterial pulse pressure waveform;
[0029] C(P) is a pressure dependent vascular compliance computed using methods proposed by Langwouters et al 1984 (“The Static Elastic Properties of 45 Human Thoracic and 20 Abdominal Aortas in vitro and the Parameters of a New Model,” J. Biomechanics, Vol. 17, No. 6, pp. 425-435, 1984);
BSA is a patient's body surface area (function of height and weight);
Age is a patient's age; and
G is a patient's gender.
[0030] The predictor variables set for computing the vascular tone factor K, using the multivariate model χ, were related to the “true” vascular tone measurement, determined as a function of CO measured through thermo-dilution and the arterial pulse pressure, for a population of test or reference subjects. This creates a suite of vascular tone measurements, each of which is a function of the component parameters of χ. The multivariate approximating function is then computed, using known numerical methods, that best relates the parameters of χ to a given suite of CO measurements in some predefined sense. A polynomial multivariate fitting function is used to generate the coefficients of the polynomial that gives a value of χ for each set of the predictor variables. Thus, the multivariate model has the following general form:
[0000]
χ
=
[
A
1
A
2
⋯
A
n
]
*
[
X
1
X
2
⋯
X
n
]
χ
=
[
A
1
A
2
⋯
A
n
]
*
[
X
1
X
2
⋯
X
n
]
(
Equation
7
)
[0000] where A 1 . . . A n are the coefficients of the polynomial multiregression model, and X are the model's predictor variables:
[0000]
X
n
,
1
=
∏
m
(
[
μ
T
1
…
μ
Tk
μ
P
1
…
μ
P
1
…
μ
Tk
C
(
P
)
BSA
Age
G
…
]
^
[
P
1
,
1
⋯
P
1
,
m
⋯
⋯
⋯
P
n
,
1
⋯
P
n
,
m
]
)
(
Equation
8
)
[0031] The method listed above relies solely on a single arterial pulse pressure measurement. Its simplicity and the fact that it does not require a calibration are advantages of this method. However, due to the empirical nature of the vascular tone assessment relationships, the accuracy of this method may be low in some extreme clinical situations where the basic empirical relationships of the model are not valid. For this reason, a second independent measurement may be beneficial if added to the basic multiregression model.
[0032] As shown above, many techniques have been devised, both non-invasive and invasive, for measuring the SV and CO, and particularly for detecting vascular compliance, peripheral resistance and vascular tone. It should be appreciated that there is a need for a system and method for estimating CO, or any parameter that can be derived from or using CO, that is robust and accurate and that is less sensitive to calibration and computational errors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 illustrates an example of two blood pressure curves representing two different arterial pressure measurements received from a subject according to an embodiment of the invention.
[0034] FIG. 2 illustrates an example of an Electrocardiogram measurement (ECG) and a blood pressure measurement received from a subject according to an embodiment of the invention.
[0035] FIG. 3 is a graph illustrating the relationship between the arterial pulse pressure propagation time and the arterial compliance according to an embodiment of the invention.
[0036] FIG. 4 is a graph illustrating the relationship between the pulse pressure propagation time and vascular tone on patients recovering from cardiac arrest according to an embodiment of the invention.
[0037] FIGS. 5-6 are graphs illustrating the correlation between the pulse pressure propagation time and vascular tone for different hemodynamic conditions of the subjects according to several embodiments of the invention.
[0038] FIGS. 7-9 are graphs illustrating the correlation between the CO computed using the pulse pressure propagation time, Continuous Cardiac Output (CCO) and CO values measured by thermodilution bolus measurements (TD-CO) for different hemodynamic states of the subjects according to several embodiments of the invention.
[0039] FIG. 10 is a graph showing the relationship between the CO estimated using the arterial pressure propagation time according to several embodiments of the invention and CO estimated using the arterial pulse pressure signal.
[0040] FIG. 11 is a block diagram showing an exemplary system used to execute the various methods described herein according to several embodiments of the invention.
[0041] FIG. 12 is a flow chart showing a method according to an embodiment of the invention.
SUMMARY OF THE INVENTION
[0042] One embodiment of the invention provides a method for determining a cardiovascular parameter including receiving an input signal corresponding to an arterial blood pressure measurement over an interval that covers at least one cardiac cycle, determining a propagation time of the input signal, determining at least one statistical moment of the input signal, and determining an estimate of the cardiovascular parameter using the propagation time and the at least one statistical moment.
[0043] One embodiment of the invention provides an apparatus for determining a cardiovascular parameter including a processing unit to receive an input signal corresponding to an arterial blood pressure measurement over an interval that covers at least one cardiac cycle, determine a propagation time of the input signal, determine at least one statistical moment of the input signal and determine an estimate of the cardiovascular parameter using the propagation time and the at least one statistical moment.
DETAILED DESCRIPTION
[0044] Methods and systems that implement the embodiments of the various features of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention. Reference in the specification to “one embodiment” or “an embodiment” is intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least an embodiment of the invention. The appearances of the phrase “one embodiment” or “an embodiment” in various places in the specification are not necessarily all referring to the same embodiment. Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements.
[0045] In broadest terms, the invention involves the determination of a cardiac value, such as a stroke volume (SV), and/or a value derived from the SV such as cardiac output (CO), using the arterial pulse pressure propagation time. The arterial pulse pressure propagation time may be measured by using arterial pressure waveforms or waveforms that are proportional to or derived from the arterial pulse pressure, electrocardiogram measurements, bioimpedance measurements, other cardiovascular parameters, etc. These measurements may be made with an invasive, non-invasive or minimally invasive instrument or a combination of instruments.
[0046] The invention may be used with any type of subject, whether human or animal. Because it is anticipated that the most common use of the invention will be on humans in a diagnostic setting, the invention is described below primarily in use with a “patient.” This is by way of example only; however, it is intended that the term “patient” should encompass all subjects, both human and animal, regardless of setting.
[0047] FIG. 1 illustrates an example of two blood pressure curves representing two different arterial pressure measurements received from a subject. The top curve represents a central arterial pressure measurement detected from the subject's aorta and the bottom curve represents a measurement detected from the subject's radial artery. The pulse pressure propagation time (t prop ) can be measured as the transit time between the two arterial pressure measurements.
[0048] The rationale of using the pulse pressure propagation time for hemodynamic measurements is based on a basic principle of cardiovascular biomechanics. That is, if the subject's heart pumped blood through a completely rigid vessel, upon contraction of the heart, the pressure waveform would instantaneously be present at any distal arterial location in the subject's body. However, if the subject's heart pumped blood through a compliant vessel, upon contraction of the heart, the pressure waveform would be present some amount of time after the heart contracted at a distal arterial location in the subject's body.
[0049] The pulse pressure propagation time can be measured invasively or non-invasively at several different locations on the pressure waveform (or any other waveform related to the pressure waveform). In the example shown on FIG. 1 , the pulse pressure propagation time may be measured by using two different arterial pressure measurements, for example, one reference measurement from the aorta and one peripheral measurement from the radial artery.
[0050] FIG. 2 illustrates an example of using an electrocardiogram signal as a reference signal for the propagation time measurement. The top curve represents an electrocardiogram (ECG) signal detected with electrodes placed near the subject's heart and the bottom curve represents an arterial pressure measurement detected from the subject's peripheral artery. In this example, the arterial pulse pressure propagation time (t prop ) may be measured by using the transit time between the ECG signal and the peripheral arterial pressure. Similarly, a transthoracic bioimpedance measurement could be used as a reference site, and the propagation time could be measured as a transit time versus a peripheral measurement derived from or proportional to the arterial blood pressure.
[0051] The arterial pulse pressure propagation time provides an indirect measure of the physical (i.e., mechanical) properties of a vessel segment between the two recording sites. These properties include primarily the elastic and geometric properties of the arterial walls. The properties of the arterial walls, for example their thicknesses and lumen diameters, are some of the major determinants of the arterial pulse pressure propagation time. As a result, the pulse pressure propagation time depends mainly on the arterial compliance.
[0052] FIG. 3 illustrates an example where the pulse pressure propagation time increases with increasing arterial compliance (C). Hence, the pulse pressure propagation time (t prop ) can be represented as a function of arterial compliance (C), i.e.,
[0000] t prop =f ( C ) (Equation 9)
[0053] The arterial pulse pressure propagation time can therefore be used as a simple measure to estimate the arterial compliance. The propagation time can be used as a separate measure to assess a patient's vascular status or can be used in a pulse contour cardiac output algorithm along with other parameters to account for the effects of vascular compliance, vascular resistance and vascular torie. In one embodiment, the arterial pulse pressure propagation time is measured using an arterial pulse pressure signal from relatively large arteries (e.g., radial, femoral, etc.) and therefore the influence of the peripheral resistance is minimal. Also, this measurement may include the average arterial compliance between the measurement sites and may not reflect the pressure dependence of the arterial compliance.
[0054] The basic relationship could be derived from the well known Bramwell-Hill equation used to calculate the pulse wave velocity (PWV):
[0000]
PWV
2
=
P
V
·
1
ρ
·
V
(
Equation
10
)
[0000] where
dP is the change in pressure;
dV is the change in volume;
ρ is the blood density; and
V is the baseline volume.
[0055] The arterial compliance (C) may be defined as the ratio of the incremental change in volume (dV) resulting from an incremental change in pressure (dP), i.e.,
[0000]
C
=
V
P
(
Equation
11
)
[0056] Substituting equation (11) into equation (10), we obtain the following equation:
[0000]
PWV
2
=
1
C
·
1
ρ
·
V
(
Equation
12
)
[0057] On the other hand PWV is defined as follows:
[0000]
PWV
=
L
t
prop
(
Equation
13
)
[0058] where L is the vascular length between the two recording sites and t prop is the arterial pulse pressure propagation time.
[0059] If equation 13 is substituted into equation 12, the arterial compliance can be given by:
[0000]
C
=
1
L
2
·
1
ρ
·
V
·
t
prop
2
(
Equation
14
)
[0060] If we define γ as:
[0000]
γ
=
1
L
2
·
1
ρ
·
V
(
Equation
15
)
[0061] The arterial compliance can be represented as:
[0000] C=γ·t prop 2 (Equation 16)
[0062] where the scaling factor γ is a function, which depends on the blood density, the effective vascular distance between the two recording sites and the basic volume, i.e., γ depends on the physical vascular volume between the two recording site and the blood viscosity (i.e., Hematocrit . . . etc).
[0063] Based on the above equations, the arterial pulse pressure propagation time can be used in a number of different ways.
[0064] 1. The use of the arterial pulse pressure propagation time to estimate arterial compliance. The pulse pressure propagation time may be used as an input to a hemodynamic model based on the standard deviation of the arterial pulse pressure to evaluate the dynamic changes in the arterial pressure created by the systolic ejection. The CO can be represented as a function of the standard deviation of the arterial pulse pressure as follow:
[0000] CO=K*std ( P )* HR (Equation 17)
[0065] where K, as we have shown above, is a scaling factor proportional to the arterial compliance, std(P) is the standard deviation of the arterial pulse pressure, and HR is the heart rate.
[0066] It is also understood that:
[0000]
CO
=
C
·
MAP
τ
(
Equation
18
)
[0067] where MAP is the mean arterial pressure, τ is an exponential pressure decay constant, and C, like K, is a scaling factor related to arterial compliance.
[0068] From equations 17 and 18, the scaling factor K is a measure equal to vascular compliance. If we substitute the scaling factor K in equation 17 for the compliance as given in equation 16, CO can be computed using the standard deviation of the arterial pulse pressure waveform and the arterial pulse pressure propagation time:
[0000] CO=γ·t prop 2 ·std ( P )· HR (Equation 19)
[0069] where standard deviation of the arterial pulse pressure can be calculated using the equation:
[0000]
std
(
P
)
=
1
n
-
1
∑
k
=
1
n
[
P
(
k
)
-
P
avg
]
2
(
Equation
20
)
[0070] where n is the total number of samples, P(k) is the instantaneous pulse pressure, and P avg is the mean arterial pressure. The mean arterial pressure can be defined as:
[0000]
P
avg
=
1
n
∑
k
=
1
n
P
(
k
)
(
Equation
21
)
[0071] FIG. 4 is a graph illustrating the relationship between the square of the arterial pulse pressure propagation time and the scaling factor K of patients during recovery from cardiac bypass surgery. FIG. 4 plots ten (10) averaged data points from ten (10) different patients. In the example of FIG. 4 , the arterial pulse pressure propagation time has been calculated as a transit time between the ECG signal and the radial arterial pressure. The data shown in FIG. 4 illustrates that the K scaling factors of equation 17 can be effectively estimated using the arterial pulse pressure propagation time as given by equation 16.
[0072] FIGS. 5 and 6 are graphs illustrating the correlation between the arterial pulse pressure propagation time and the K scaling factor of equation 17 for different hemodynamic states of two subjects. Both trends correspond to animal data taken from experiments using porcine animal models. These figures show identical trends of the scaling factor K and the square of the pulse pressure propagation time. The data on FIGS. 5 and 6 illustrate that the K or the C scaling factors of equations 17 and 18 can be effectively estimated using the arterial pulse pressure propagation time.
[0073] The scaling factor γ of equation 19 can be determined using any pre-determined function of the propagation time and the pressure P(t); thus,
[0000] γ=Γ( t prop ,P ) (Equation 22)
[0000] where Γ is a pre-determined function of the propagation time and pressure, used to develop computational methods to estimate γ.
[0074] Any known, independent CO technique may be used to determine this relationship, whether invasive, for example, thermodilution, or non-invasive, for example, trans-esophageal echocardiography (TEE) or bio-impedance measurement. The invention provides continuous trending of CO between intermittent measurements such as TD or TEE.
[0075] Even if an invasive technique such as catheterization is used to determine γ, it will usually not be necessary to leave the catheter in the patient during the subsequent CO-monitoring session. Moreover, even when using a catheter-based calibration technique to determine γ, it is not necessary for the measurement to be taken in or near the heart; rather, the calibration measurement can be made in the femoral artery. As such, even where an invasive technique is used to determine γ, the invention as a whole is still minimally invasive in that any catheterization may be peripheral and temporary.
[0076] As discussed above, rather than measure arterial blood pressure directly, any other input signal may be used that is proportional to blood pressure. This means that calibration may be done at any or all of several points in the calculations. For example, if some signal other than arterial blood pressure itself is used as an input signal, then it may be calibrated to blood pressure before its values are used to calculate standard deviation, or afterwards, in which case either the resulting standard deviation value can be scaled, or the resulting SV value can be calibrated (for example, by setting γ properly), or some final function of SV (such as CO) can be scaled. In short, the fact that the invention may in some cases use a different input signal than a direct measurement of arterial blood pressure does not limit its ability to generate an accurate SV estimate.
[0077] In addition to the blood viscosity, y depends mainly of the physical vascular volume between the two recording sites. Of course, the effective length (L) and the effective volume (V) between the two recording sites can not be known. Vascular branching and the patient to patient differences are two main reasons why the effective physical vascular volume between the two recording sites can not be known. However, it is obvious that this physical volume is proportional to the patient's anthropometric parameters and therefore it can be estimated indirectly using the patient's anthropometric parameters. The anthropometric parameters may be derived from various parameters such as the measured distance ( 1 ) between the two recording sites, patient's weight, patient's height, patient's gender, patient's age, patient's bsa, etc., or any combination of these factors. In one embodiment, all the anthropometric parameters, for example, the distance ( 1 ) between the two recording sites, patient's weight, patient's height, patient's gender, patient's age and patient's bsa, may be used to compute γ. Additional values are preferably also included in the computation to take other characteristics into account. In one embodiment, the heart rate HR (or period of R-waves) may be used. Thus,
[0000] γ=Γ M ( l,H,W,BSA ,Age, G,HR ) (Equation 23)
[0078] Where
[0000] l is the measured distance between the two recording sites;
H is the patient's height;
W is the patient's weight;
BSA is the patient's bsa;
Age is the patient's age;
G is the patient's gender;
HR is the patient's heart rate; and
ΓM is a multivariate model.
[0079] The predictor variables set for computing γ, using the multivariate model Γ, are related to the “true” vascular compliance measurement, determined as a function of CO measured through thermo-dilution and the arterial pulse pressure, for a population of test or reference subjects. This creates a suite of compliance measurements, each of which is a function of the component parameters of Γ M . The multivariate approximating function is then computed using numerical methods that best relates the parameters of Γ M to a given suite of CO measurements in a predefined manner. A polynomial multivariate fitting function is used to generate the coefficients of the polynomial that give a value of Γ M for each set of the predictor variables. Thus, the multivariate model has the following general equation:
[0000]
Γ
M
=
[
a
1
a
2
⋯
a
n
]
*
[
Y
1
Y
2
⋮
Y
n
]
(
Equation
24
)
[0080] where a 1 . . . a n are the coefficients of the polynomial multiregression model, and Y are the model's predictor variables:
[0000]
Y
n
,
1
=
∏
m
(
[
l
H
W
BSA
Age
G
HR
]
⋀
[
P
1
,
1
⋯
P
1
,
m
⋯
⋯
⋯
P
n
,
1
⋯
P
n
,
m
]
)
(
Equation
25
)
[0081] The use of the arterial pulse pressure propagation time to estimate vascular tone. Vascular tone is a hemodynamic parameter used to describe the combined effect of vascular compliance and peripheral resistance. In the prior art, the shape characteristics of the arterial pressure waveform in combination with patients anthropometric data and other cardiovascular parameters were used to estimate vascular tone (see Roteliuk, 2005, “Arterial pressure-based automatic determination of a cardiovascular parameter”). The arterial pulse pressure propagation time can also be used to estimate vascular tone. In one embodiment, the arterial pulse pressure propagation time can be used as an independent term to a multivariate regression model to continuously estimate vascular tone. In one embodiment, the arterial pulse pressure propagation time can be used in combination with the shape information of the arterial pulse pressure waveform to estimate the vascular tone. The higher order shape sensitive arterial pressure statistical moments and the pressure-weighted time moments may be used as predictor variables in the multivariate model along with the arterial pulse pressure propagation time. Additional values are preferably also included in the computation to take other characteristics into account. For example, the heart rate HR (or period of R-waves), the body surface area BSA, as well as a pressure dependent non-linear compliance value C(P) may be calculated using a known method such as described by Langwouters, which computes compliance as a polynomial function of the pressure waveform and the patient's age and sex. Thus,
[0000] K =χ( t prop , μ T1 , μ T2 , . . . μ Tk , μ P1 , μ P2 , . . . μ Pk , C ( P ), BSA , Age, G . . . ) (Equation 26)
[0082] where
K is vascular tone;
X is a multiregression statistical model;
[0083] t prop is the arterial pulse pressure propagation time;
μ 1T . . . μ kT are the 1-st to k-th order time domain statistical moments of the arterial pulse pressure waveform;
μ 1P . . . μ kP are the lest to k-th order pressure weighted statistical moments of the arterial pulse pressure waveform;
[0084] C(P) is the pressure dependent vascular compliance as defined by Langwouters et al. (“The Static Elastic Properties of 45 Human Thoracic and 20 Abdominal Aortas in vitro and the Parameters of a New Model,” J. Biomechanics, Vol. 17, No. 6, pp. 425-435, 1984);
BSA is the patient's body surface area (function of height and weight);
Age is the patient's age; and
Gender is the patient's gender.
[0085] Depending on the needs of a given implementation of the invention, one may choose not to include either skewness or kurtosis, or one may include even higher order moments. The use of the first four statistical moments has proven successful in contributing to an accurate and robust estimate of compliance. Moreover, anthropometric parameters other than the HR and BSA may be used in addition, or instead, and other methods may be used to determine C(P), which may even be completely omitted.
[0086] The exemplary method described below for computing a current vascular tone value may be adjusted in a known manner to reflect the increased, decreased, or altered parameter set. Once the parameter set for computing K has been assembled, it may be related to a known variable. Existing devices and methods, including invasive techniques, such as thermo-dilution, may be used to determine CO, HR and SV est for a population of test or reference subjects. For each subject, anthropometric data such as age, weight, BSA, height, etc. can also be recorded. This creates a suite of CO measurements, each of which is a function (initially unknown) of the component parameters of K. An approximating function can therefore be computed, using known numerical methods, that best relates the parameters to K given the suite of CO measurements in some predefined sense. One well understood and easily computed approximating function is a polynomial. In one embodiment, a standard multivariate fitting routine is used to generate the coefficients of a polynomial that gave a value of K for each set of parameters t prop , HR, C(P), BSA, μ 1P , σ P , μ 3P , μ 4P μ 1T , σ T , μ 3T , μ 4T .
[0087] In one embodiment, K is computed as follows:
[0000]
K
=
[
A
1
A
2
⋯
A
n
]
*
[
X
1
X
2
⋯
X
n
]
where
(
Equation
27
)
X
n
,
1
=
∏
m
(
[
t
prop
,
μ
T
1
,
μ
T
2
,
…
μ
T
2
,
μ
P
1
,
μ
P
2
,
…
μ
Pk
,
C
(
P
)
,
BSA
,
Age
,
G
…
]
^
[
P
1
,
1
⋯
P
1
,
m
⋯
⋯
⋯
P
n
,
1
⋯
P
n
,
m
]
)
(
Equation
28
)
[0088] 3. The use of the arterial pulse pressure propagation to directly estimate CO is discussed below.
[0089] The pulse pressure propagation time may be used as an independent method to estimate CO. That is, the arterial pulse pressure propagation time is independently proportional to SV, as shown below:
[0000]
SV
=
K
p
·
1
t
prop
(
Equation
29
)
[0090] CO can be estimated if we multiply equation 29 by HR:
[0000]
CO
=
K
p
·
1
t
prop
·
HR
(
Equation
30
)
[0091] The scaling factor K p can be estimated using a direct calibration, for example, using a known CO value from a bolus thermo-dilution measurement or other gold standard CO measurement. FIGS. 7-9 are graphs illustrating the correlation between the CO computed using the pulse pressure propagation time as shown in equation 30 (COprop), Continuous Cardiac Output (CCO) and CO values measured by intermittent thermodilution bolus measurements (ICO). CCO and ICO are measured using the Vigilance monitor manufactured by Edwards Lifesciences of Irvine, Calif. The measurements have been performed on animal porcine models in different hemodynamic states of the animals. These graphs show experimentally that changes in CO are related to changes in the pulse pressure propagation time and that the pulse pressure propagation time can be used as an independent method to estimate CO.
[0092] The scaling factor K p of equation 30 can be determined using any pre-determined function of the propagation time and CO or SV. Any independent CO technique may be used to determine this relationship, whether invasive, for example, thermo-dilution, or non-invasive, for example, trans-esophageal echocardiography (TEE) or bio-impedance measurement. The invention provides continuous trending of CO between intermittent measurements such as TD or TEE.
[0093] Even if an invasive technique such as catheterization is used to determine K p , it may not be necessary to leave the catheter in the patient during the subsequent CO-monitoring session. Moreover, even when using catheter-based calibration technique to determine K p , it may not be necessary for the measurement to be taken in or near the heart; rather, the calibration measurement can be made in the femoral artery. As such, even where an invasive technique is used to determine K p , the method is still minimally invasive in that any catheterization may be peripheral and temporary.
[0094] The approach shown in equation 30 allows measuring CO to be performed completely non-invasively if non-invasive techniques are used to measure the propagation time and if a predefined function or relationship is used to measure K p . The non-invasive techniques to measure the propagation time can include, but are not limited to: ECG, non-invasive arterial blood pressure measurements, bio-impedance measurements, optical pulse oximetry measurements, Doppler ultrasound measurements, or any other measurements derived from or proportional to them or any combination of them (for example: using Doppler ultrasound pulse velocity measurement to measure the reference signal near the heart and using a bio-impedance measurement to measure the peripheral signal . . . etc).
[0095] The scaling factor K p , depends mainly on blood viscosity and the physical vascular distance and volume between the two recording sites. Of course, the effective length (L) and the effective volume (V) between the two recording sites can not be known. Vascular branching and the patient to patient differences are two main reasons why the effective physical vascular volume between the two recording sites can not be known. However, the physical volume may be proportional to the patient's anthropometric parameters and therefore it can be estimated indirectly using the patient's anthropometric parameters. The anthropometric parameters may be derived from various parameters such as the measured distance (L) between the two recording sites, patient's weight, patient's height, patient's gender, patient's age, patient's bsa etc., or any combination of these parameters. In one embodiment, all the anthropometric parameters: the distance (L) between the two recording sites, patient's weight, patient's height, patient's gender, patient's age and patient's bsa are used to compute K p . Thus,
[0000] K p =M ( L,H,W,BSA ,Age, G ) (Equation 31)
[0096] where
L is the measured distance between the two recording sites;
H is the patient's height;
W is the patient's weight;
BSA is the patient's bsa;
Age is the patient's age;
G is the patient's gender; and
M is a multivariate linear regression model.
[0097] The predictor variables set for computing K p , using the multivariate model M, are related to the “true” CO measurement, determined as a function of the propagation time, where CO is measured through thermo-dilution, for a population of test or reference subjects. This creates a suite of measurements, each of which is a function of the component parameters of M. The multivariate approximating function is then computed using numerical methods that best relates the parameters of M to a given suite of CO measurements in some predefined sense. A polynomial multivariate fitting function is used to generate the coefficients of the polynomial that give a value of M for each set of the predictor variables. Thus, the multivariate model has the following equation:
[0000]
M
=
[
a
1
a
2
⋯
a
n
]
*
[
Y
1
Y
2
⋯
Y
n
]
(
Equation
32
)
[0098] where a 1 . . . a n are the coefficients of the polynomial multiregression model, and Y are the model's predictor variables:
[0000]
Y
n
,
1
=
∏
m
(
[
L
H
W
BSA
Age
G
]
^
[
P
1
,
1
⋯
P
1
,
m
⋯
⋯
⋯
P
n
,
1
⋯
P
n
,
m
]
)
(
Equation
33
)
[0099] FIG. 10 is a graph showing the relationship between the CO estimated using equation 17 (CO std on the x-axis) and CO estimated using equation 30 (CO prop on the y-axis) from a series of animal experiments. The data shows CO measurements from a total of ten (10) pigs. Three (3) selected data points from each pig are used for the graph. In order to cover a wide CO range, each selected data point corresponds to a different hemodynamic state of the pig: vasodilated, vasoconstricted and hypovolemic states, respectively. The proportionality shown in FIG. 10 is experimental proof of the effectiveness and the reliability of using the propagation time to estimate CO.
[0100] FIG. 11 is a block diagram showing an exemplary system used to execute the various methods described herein. The system may include a patient 100 , a pressure transducer 201 , a catheter 202 , ECG electrodes 301 and 302 , signal conditioning units 401 and 402 , a multiplexer 403 , an analog-to-digital converter 405 and a computing unit 500 . The computing unit 500 may include a patient specific data module 501 , a scaling factor module 502 , a moment module 503 , a standard deviation module 504 , a propagation time module 505 , a stroke volume module 506 , a cardiac output module 507 , a heart rate module 508 , an input device 600 , an output device 700 , and a heart rate monitor 800 . Each unit and module may be implemented in hardware, software, or a combination of hardware and software.
[0101] The patient specific data module 501 is a memory module that stores patient data such as a patient's age, height, weight, gender, BSA, etc. This data may be entered using the input device 600 . The scaling factor module 502 receives the patient data and performs calculations to compute the scaling compliance factor. For example, the scaling factor module 502 puts the parameters into the expression given above or into some other expression derived by creating an approximating function that best fits a set of test data. The scaling factor module 502 may also determine the time window [t 0 , tf] over which each vascular compliance, vascular tone, SV and/or CO estimate is generated. This may be done as simply as choosing which and how many of the stored, consecutive, discretized values are used in each calculation.
[0102] The moment module 503 determines or estimates the arterial pulse pressure higher order statistical time domain and weighted moments. The standard deviation module 504 determines or estimates the standard deviation of the arterial pulse pressure waveform. The propagation time module 505 determines or estimates the propagation time of the arterial pulse pressure waveform.
[0103] The scaling factor, the higher order statistical moments, the standard deviation and the propagation time are input into the stroke volume module 506 to produce a SV value or estimate. A heart rate monitor 800 or software routine 508 (for example, using Fourier or derivative analysis) can be used to measure the patient's heart rate. The SV value or estimate and the patient's heart rate are input into the cardiac output module 507 to produce an estimate of CO using, for example, the equation CO=SV*HR.
[0104] As mentioned above, it may not be necessary for the system to compute SV or CO if these values are not of interest. The same is true for the vascular compliance, vascular tone and peripheral resistance. In such cases, the corresponding modules may not be necessary and may be omitted. For example, the invention may be used to determined arterial compliance. Nonetheless, as FIG. 11 illustrates, any or all of the results, SV, CO, vascular compliance, vascular tone and peripheral resistance may be displayed on the output device 700 (e.g., a monitor) for presentation to and interpretation by a user. As with the input device 600 , the output device 700 may typically be the same as is used by the system for other purposes.
[0105] The invention further relates to a computer program loadable in a computer unit or the computing unit 500 in order to execute the method of the invention. Moreover, the various modules 501 - 507 may be used to perform the various calculations and perform related method steps according to the invention and may also be stored as computer-executable instructions on a computer-readable medium in order to allow the invention to be loaded into and executed by different processing systems.
[0106] While certain exemplary embodiments have been described and shown in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of and not restrictive on the broad invention, and that this invention not be limited to the specific constructions and arrangements shown and described, since various other changes, combinations, omissions, modifications and substitutions, in addition to those set forth in the above paragraphs, are possible. Those skilled in the art will appreciate that various adaptations and modifications of the just described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein. | A method and apparatus for determining a cardiovascular parameter including receiving an input signal corresponding to an arterial blood pressure measurement over an interval that covers at least one cardiac cycle, determining a propagation time of the input signal, determining at least one statistical moment of the input signal, and determining an estimate of the cardiovascular parameter using the propagation time and the at least one statistical moment. | 0 |
FIELD OF THE INVENTION
[0001] The present invention relates to a method and a device for coordinating the subsystem of a vehicle dynamics network system. The increasing complexity and the rising number of electronic systems in vehicles, which actively affect handling characteristics or vehicle stability, requires a controller network in order to achieve an optimal interaction of the individual electronic systems.
BACKGROUND INFORMATION
[0002] European Patent no. 0 507 072 discusses a network system, which relays the instruction to execute the driver command in a hierarchical structure of an overall system from top to bottom. This results in a clear structure having elements independent of one another.
[0003] German patent document no. 44 39 060 discusses a complex vehicle control system, which combines, for example, an antilock braking system (ABS) with a traction control system (TCS) and a yaw moment control (GMR) in a vehicle stability control (FSR). If an error occurs in this control system, then, if possible, only the affected component will be switched off.
[0004] German patent document no. 41 40 270 discusses a method, in which, during braking and/or acceleration maneuvers, the suspension systems are operated in such a way that on every wheel unit the current normal force between tire and road surface, or the wheel load, is influenced in the direction of its highest possible value.
[0005] German patent document no. 39 39 292 discusses a network control system comprising an active chassis control and an antilock braking system (ABS) and/or traction control system components (TCS), which, during the ABS or TCS control phases, always implement the damping force adjustments in such a way that wheel load fluctuations are minimal.
SUMMARY OF THE INVENTION
[0006] The exemplary embodiment and/or exemplary method of the present invention is to a method or a device for influencing the handling characteristics of a vehicle. The influence is directed at increasing the vehicle stability while maintaining the driving comfort for the driver of the vehicle. This goal is achieved by activating at least two systems in the vehicle, which improve the handling characteristics and hence the vehicle stability. The activation of a system occurs in a specified sequence as a function of the activation and/or of the effect of the preceding systems on the handling characteristics achieved by the activation.
[0007] The emphasis here is primarily on the stabilization of the handling characteristics. The sequence is established on the basis of the effects of the interventions of the systems on the handling characteristics. A further important aspect in the choice of the sequence of the activated systems is the perceptible driving comfort of the driver. Thus priority is given to the intervention of a system, in which the driver of the vehicle least notices the effect of the intervention on the handling characteristics, i.e. the stabilizing effect. For example, an additional steering intervention for stabilizing the vehicle, which is superimposed on the steering interventions on the part of the driver and produced by the activated steering system, is noticed more distinctly than an intervention of the chassis system (e.g. an adjustment of the hardness of the spring or damper). Furthermore, a driver senses a braking action and hence a change in the longitudinal movement of the vehicle more strongly than is the case in an additional steering intervention. With the activation of a chassis system, followed by a steering system and finally a brake system, this results in a prioritization of the activation, which provides the driver with an increased vehicle stability with a high driving comfort at a minimal loss of speed or an optimized braking deceleration performance. The advantage vis-à-vis available strategies for peaceful coexistence is the increase of the overall utility without giving up the basic idea of autonomous subsystems.
[0008] In the exemplary embodiment and/or exemplary method of the present invention, the operating state of the activated system and/or the achievable effect on the handling characteristics are taken into account in the activation of the systems. This allows for a situation-dependent activation of the individual actuators of the system.
[0009] The exemplary embodiment and/or exemplary method of the present invention ascertains a deviation between specifiable nominal handling characteristics and the current actual handling characteristics. The handling characteristics are influenced subsequently by the activation of the systems as a function of the ascertained deviation.
[0010] In a further embodiment, the deviation between specified nominal handling characteristics, provided in particular as handling characteristics according to the driver command, and the current actual handling characteristics is ascertained by a stabilization variable, which represents the deviation. It is furthermore provided that a nominal yaw moment is assigned to the stabilization variable as a function of the stabilization variable. The activation of the systems can subsequently occur as a function of the ascertained nominal yaw moment.
[0011] An advantage of the exemplary embodiment and/or exemplary method of the present invention lies in the fact that the activation of the systems reduces the ascertained deviation between nominal and actual handling characteristics to a minimum. An increase in vehicle stability can thereby be achieved. The functional activation of the systems in the specified sequence is arranged or configured to reduce the deviation to a minimum by the activation of a preceding system. The reduction of the deviation achieved in preceding systems is then taken into account in the activation of the subsequent systems.
[0012] Checking the necessity of activating subsequent systems, which is performed following the implemented activation of a preceding system, also has an advantageous effect. Thus, if the deviation between the nominal and the actual handling characteristics has been sufficiently reduced by preceding systems, an activation of subsequent systems in the sequence may be omitted.
[0013] For influencing handling characteristics, particularly vehicle stability, the exemplary embodiment and/or exemplary method of the present invention is arranged or configured to influence a force between the vehicle body and at least one wheel unit by activating a chassis system. For example, an advantageous adjustment of the spring and/or damping property of the chassis may be performed on this basis. The handling characteristics may be additionally influenced by activating the position of at least one steerable wheel of a steering system. As in the case of a chassis system and a steering system, an advantageous influence on the handling characteristics may also be exerted via the activation of a brake system. Thus the activation of the braking force of at least one wheel of the motor vehicle can have a favorable effect on the handling characteristics in that critical driving situations are detected and mitigated independently of the situation of the driver.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 shows the intake of the operating parameters of the systems within the vehicle controller network as well as the activation of the vehicle dynamics systems.
[0015] FIG. 2 shows in a flow chart the processing of the deviation between nominal and actual handling characteristics and the influence of the vehicle dynamics systems on the handling characteristics.
[0016] FIG. 3 shows the control sequence in the vehicle network system.
[0017] FIG. 4 shows the algorithm for calculating the normal force intervention of a chassis system in the vehicle network.
[0018] FIG. 5 shows the determination of the lateral force intervention of a steering system.
[0019] FIG. 6 shows the determination of the longitudinal force intervention of a brake system.
DETAILED DESCRIPTION
[0020] FIG. 1 shows an exemplary embodiment for influencing the handling characteristics of a motor vehicle, with special emphasis being placed on increasing the vehicle stability. In addition to the current actual yaw rate Ψ act ( 160 ) from a yaw-rate sensor 110 , the performance quantities 170 , 180 , 190 of the existing systems, chassis control 120 , steering 130 and vehicle dynamics control 140 , are read in the control block 100 . From the ascertained or determined performance quantities ( 170 , 180 , 190 ), the nominal yaw rate In case of a deviation between the actual value 160 and the nominal value 210 of the yaw rate On the basis of these interventions, the roll inclination may be suppressed by stabilizing interventions 175 using a chassis system 120 , as can be implemented, for example, by an electronic active roll stabilizer (EAR) or an active body control (ABC). In addition, with the use of such a chassis component, the roll momentum distribution (e.g. the oversteering and understeering behavior) may be influenced.
[0021] With the help of a steering system 130 , as featured in electronic active steering (EAS) or steer by wire (SbW) systems, in addition to the steering movements of the driver, steering interventions 185 , which result in an increase in the vehicle stability may be superimposed on the steering. In addition, with the activation of a vehicle dynamics control 140 , as is implemented by an electronic stability program (ESP), vehicle-stabilizing brake interventions 195 may be undertaken.
[0022] In a block diagram, FIG. 2 depicts the mode of operation in the ascertainment of the necessary control interventions for increasing the vehicle stability. By comparing a suitable actual value 200 with nominal value 210 , a system deviation 230 is ascertained in block 220 . System deviation 230 , for example, can be formed by a difference between the actual yaw rate Furthermore, however, a formation of the system deviation by comparing the actual sideslip angles with the nominal sideslip angles is conceivable as well. Based on system deviation 230 thus obtained, a nominal yaw moment M Z ( 250 ) with regard to the vehicle's gravitational center is calculated in block 240 for the required stabilization of the handling characteristics. Nominal yaw moment M z ( 250 ) thus ascertained from system deviation 230 is relayed as an actuating command to vehicle controller network 260 . From this vehicle controller network, chassis system 120 , steering system 130 and brake system 140 are activated in the specified sequence and as a function of their possible influence on the handling characteristics.
[0023] The flow chart in FIG. 3 shows the implementation of the activation of the control systems in the specified sequence and as a function of nominal yaw moment M z ( 250 ). Based on the originally ascertained nominal yaw moment M z ( 250 ), a modification is performed on nominal yaw moment 250 in block 300 , which is necessary due to a residue moment 360 of a preceding control intervention. In block 310 , current nominal yaw moment 302 thus ascertained is used as a function of current performance quantities 170 of the chassis to determine the intervention of chassis system 120 in the moment modification of the vehicle's gravitational center. In the process, the calculated chassis interventions are converted into actuating commands 175 for the chassis. The moment modification with regard to the vehicle's gravitational center produced by the intervention in chassis system 120 is subsequently determined in block 315 and is used in block 320 for modifying nominal yaw moment 302 .
[0024] The residue yaw moment 322 thus produced is then used in block 330 , corresponding to the procedure in the activation of the chassis control, as a function of the current performance quantities of steering 180 for determining the intervention of steering system 130 in the moment modification of the vehicle's center of gravity. In the process, the calculated steering interventions are converted into actuating commands 185 for steering system 130 . The moment modification with regard to the vehicle's gravitational center produced by the intervention is then determined in block 335 and is used in block 340 for modifying residue yaw moment 322 . Residue yaw moment 342 thus produced is subsequently used in block 350 , corresponding to the procedure in the activation of the preceding vehicle controls, as a function of the current performance quantities ( 190 ) of the brake system for determining the intervention of brake system 140 in the moment modification of the vehicle's center of gravity. In the process, the calculated brake interventions are converted into actuating commands 185 for the brake system.
[0025] The moment modification with regard to the vehicle's gravitational center produced by the intervention is then determined in block 355 and is used in block 360 for modifying residue yaw moment 342 . If it is established in the process that following the brake intervention there is still a remaining residue moment 362 , then this can be used via a model correction 365 to perform an additive correction of the moment balance in block 300 . Using nominal yaw moment 302 thus updated, the activation of the control systems can be run through anew.
[0026] The calculation and the verification of the chassis interventions is represented in the flow chart of FIG. 4 . These interventions can be used to produce modifications of the normal forces that act from the wheels perpendicularly to the ground below. In the present exemplary embodiment, the modification of the normal forces at the wheels of the vehicle is used to bring about a modification of the nominal yaw moment M z ( 302 ) with regard to the gravitational center. For calculating the required normal force interventions, a controller algorithm is used in block 400 . For activating the individual actuators of chassis system 120 , the actuating reserves 430 of the normal forces at the actuators as well as the current operating state of the actuators of the chassis are taken into account. In this manner, for example, the situation can be prevented that an actuator is activated which has no road adhesion and which hence cannot effect a modification of the normal force. Furthermore, the failure of an actuator can be taken into account in the activation. Via an inverse vehicle model in block 400 , the required nominal actuating variables 405 are ascertained from the intervention selection made and are transferred to the control unit of chassis system 120 .
[0027] As feedback of the chassis system, the actual actuating variables 415 of the actuators are queried in block 420 . Together with the general operating state variables of the components and a chassis model, these actual actuating variables 415 are converted into a normal force distribution. This distribution is used to determine the actuating reserves of normal forces 430 . Finally, in block 440 , the moment modification with regard to the vehicle's gravitational center through the chassis interventions is estimated with the help of the vehicle geometry. The reduction of the yaw moment thereby ascertained is subtracted from nominal yaw moment 302 and yields residue yaw moment 322 .
[0028] Following the procedure in ascertaining the interventions of the chassis control for modifying the yaw moment in FIG. 4 , the flow chart of FIG. 5 shows the calculation and the verification of the steering interventions of steering system 130 . In the present exemplary embodiment, the modification of residue yaw moment 322 with regard to the gravitational center is brought about by a modification of the lateral forces on the steerable wheels. For calculating the required lateral force interventions, a controller algorithm is used in block 500 . For activating steering system 130 , actuating reserves 530 of the lateral forces on the wheels are taken into account as well as the current operating state of the wheels.
[0029] In this manner, for example, the situation can be prevented that a wheel is activated which has no road adhesion and which hence cannot effect a modification of the lateral force. Via an inverse vehicle model, the required nominal steering angles 505 of the wheels are calculated and transferred to steering system 130 . As feedback of the steering system, the actual steering angles 515 of the wheels are queried in block 520 . Together with a tire model, actuating reserves 530 for modifying the lateral forces are ascertained from these actual steering angles 515 . Finally, in block 540 , the moment modification with regard to the vehicle's gravitational center through the steering interventions is estimated with the help of the vehicle geometry. The reduction of the yaw moment thus ascertained is subtracted from residual yaw moment 322 , thereby yielding the new, updated residual yaw moment 342 .
[0030] As already shown in the chassis interventions in FIG. 4 and the steering interventions in FIG. 5 , FIG. 6 shows a flow chart describing the calculation, control and verification of the brake interventions. In the present exemplary embodiment, the modification of residue yaw moment 342 with regard to the gravitational center is brought about by a modification of the longitudinal force on the vehicle. For calculating the required longitudinal force interventions, a controller algorithm is used in block 600 . For activating the individual actuators of brake system 140 , actuating reserves 630 of the longitudinal forces on the wheel brakes of the vehicle as well as the current operating state of the brake system are taken into account. In this manner, for example, the situation can be prevented that a brake activation by the vehicle controller network counteracts another brake activation.
[0031] The ascertained brake interventions are transferred to the control unit of brake system 140 via an inverse vehicle model as required nominal variables 605 on the wheels. As feedback of brake system 140 , actual slip variables 615 are queried in block 620 . Together with the general operating state variables of the brake system and a chassis model, these actual slip variables 615 are converted into a longitudinal force distribution. This distribution can be used to determine actuating reserves 630 of the longitudinal forces. Finally, in block 640 , the moment modification with regard to the vehicle's gravitational center through the brake interventions is estimated with the help of the vehicle geometry. The thus ascertained reduction of the yaw moment is subtracted from residue yaw moment 342 and yields a possibly remaining residual moment 362 . | A method and a device for influencing the handling characteristics of a vehicle, by increasing the vehicle stability and hence increasing the driving comfort for the driver of the vehicle. This is done by activating at least two systems in the vehicle, which improve the handling characteristics and thus the vehicle stability. The activation of a system occurs in a specified sequence as a function of the activation and/or of the effect of the preceding systems on the handling characteristics achieved by the activation. The sequence provided for this purpose is the initial activation of a chassis system, followed by a steering system and finally by a brake system. | 1 |
FIELD OF THE INVENTION
[0001] The present invention relates to improved fire-retardant formulations. More specifically, the present invention relates to improved fire-retardant formulations for styrene polymers and more particularly for High Impact Polystyrene (HIPS) and Acrylonitrile-Butadiene-Styrene terpolymer (ABS).
BACKGROUND
[0002] Styrenic resins are widely used in many applications including those where fireproof materials are necessary. Such applications include for example TV cabinets, in which there is a need for the incorporation of fire-retardants (FR) in styrene-polymeric materials.
[0003] Traditional FRs for these applications include, inter cilia, decabromodiphenyl oxide and more recently tris(2,4,6-tribromophenoxy)-s-triazine the latter known as FR-245. The advantages of FR-245 are good balance of properties, high level of mechanical properties, high processing heat stability, good light stability, high melt flow and no blooming. However, unlike formulations based on decabromodiphenyl oxide, the formulations based on FR-245 tend to induce long after glow time. This effect is enhanced when carbon black is added to the formulation.
[0004] JP 11323064 discloses the incorporation of fire-retardant formulation comprising tris(2,4,6-tribromophenoxy)-s-triazine known as FR-245, tris(3-bromo-2,2(bromomethyl)propyl)phosphate known as FR-370, antimony trioxide (Sb203) and PTFE (polytetrafluoroethylene) in rubber reinforced polystyrene also known as HIPS, wherein the bromine content, the main component responsible for fire retardation, is between 9.5 and 11 wt. % and wherein antimony trioxide, serving as a synergist, is between 3.5 and 3.7 wt. %.
[0005] This formulation is claimed to successfully meet the requirement of UL-94 class V-0 according to the flammability tests, where five specimens are ignited, twice each, and the fulfillment of 5 requirements is necessary to pass a UL-94 V-0 standard, namely:
[0000] 1. Maximum after flame time≦10 seconds (for each ignition).
2. Total after flame time of 10 ignitions less or equal to 50 seconds.
3. Maximum after flame+after glow time less or equal to 30 seconds.
4. None of the test specimens burns or glows up to the holding clamp.
5. No cotton ignition by dripping.
[0006] UL-94V is UL (Underwriter Laboratories) Standard for Safety for Tests for Parts in Devices and Appliances.
[0007] A fire-retardant formulation containing FR-245 with 11.5 wt. % Br, 0.08 wt. % PTFE and 3.5 wt. % antimony trioxide is also rated UL-94 V-0, but reducing the bromine content to 10.5 wt. % Br results in derating to UL-94 V-1 because of long afterglow time. JP 11323064 overcomes this problem by introducing FR-370 to the formulation, which effectively reduces that time, while keeping relatively low levels of bromine-based fire-retardant.
[0008] Although JP 11323064 states that incorporation of FR-370 in the formulation allows maintaining low levels of bromine, which enhances technical properties of articles incorporating it and leads to cost-effective FR formulations, the inventors of the present invention note that FR-370 is a very expensive material and its use in fire-retardant formulations offers a high-cost non-economical solution for reducing or eliminating the afterglow phenomenon and for achieving V-0 flammability test rating.
SUMMARY OF THE INVENTION
[0009] The applicants have surprisingly found that by lowering the concentration levels of antimony trioxide to certain ranges while maintaining low levels of bromine, a fire-retardant formulation that essentially meets the requirement UL-94 class V-0 standards is achieved without evoking the need for high-cost or other materials. In particular, it has also been found that even when incorporating additives to the formulation as carbon black pigment those concentration ranges of the respective components still allow to successfully pass the standard flammability tests.
[0010] It is therefore an object of the present invention to provide a fire-retardant formulation that essentially meets the requirement standard according to the flammability tests.
[0011] It is yet another object of the present invention to provide a pigmented fire-retardant formulation that essentially meets the requirement standard according to the flammability tests.
[0012] Still another object of the present invention is to provide a fire-retardant formulation with improved technical and mechanical properties.
[0013] Still another object of the present invention is to provide a fire-retardant formulation that is cost-effective.
[0014] Still another object of the present invention is to provide a fire-retarded styrene-containing polymer for injection molding or extrusion essentially comprising said fire-retardant formulation.
[0015] Still another object of the present invention is to provide fire-retarded styrene-containing polymer that may be HIPS or ABS.
[0016] This and other objects of the invention will become apparent as the description proceeds.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The present invention provides a fire-retardant formulation that meets the requirement UL-94 V-0 standard according to the flammability tests and which is also cost-effective.
[0018] According to the present invention the formulation comprises FR-245, antimony trioxide, PTFE and optionally carbon black pigment, in which the acceptable concentrations of bromine range between about 9.0 and about 10.5 wt. % and those of antimony trioxide range between about 1.8 and about 3.2 wt. %.
[0019] Styrene rubber reinforced polymers containing fire-retardant formulations (FR-HIPS) are often required to possess a black or gray color. This is achieved by the incorporation of carbon black, a preferred pigment, to these formulations. However, a side-effect of carbon black when introduced in a fire-retardant formulation is long period of time afterglow effect, where the formulation comprises essentially the same components having the same concentrations as disclosed in JP 11323064, excluding the presence of FR-370.
[0020] In addition to the polystyrenic polymer, halogen based fire retardant, antimony oxide, PTFE and the carbon black, there can be present in the formulation conventional additives in their conventional amounts. Examples of such additives are: fillers, pigments, dyes, impact modifiers, UV stabilizers, antioxidants, processing aids, nucleating agents, lubricants and the like.
[0021] The flame retarded formulations may be shaped into the final object by processes that are well known to the person skilled in the art; non limiting examples of such processes are: injection molding, extrusion, press molding, vacuum forming, etc.
EXAMPLES
[0022] The present invention will now be described in more detail with Examples and Reference Examples.
[0023] Tables 1-3 below summarize the materials used for the preparation of the test samples as well as the methods and conditions for their preparation. Flammability was tested according to UL-94V.
[0000]
TABLE 1
Materials
TRADE NAME
GENERAL INFO
HIPS
Styron 472 ex Dow Chemical
ABS
Magnum 3404 ex Dow Chemical
Antimony trioxide
ACC-BS ex Antraco
FR-245 ex DSBG
Tris(2,4,6-tribromophenoxy)-s-
triazine
F-3020 ex DSBG
Endcapped brominated epoxy
oligomer (MW 2,000)
FR-1210 ex DSBG
Decabromodiphenyl oxide
Carbon Black
PSB 183 ex Hubron
manufacturing division limited
PTFE
Hostaflon 2071 ex Dynon-fine
powder (500μ)
Antimony trioxide is added as 80% concentrate in polystyrene carrier.
Carbon black is added as 35% concentrate in polystyrene carrier.
Compounding
[0024] All formulations were prepared under the same conditions.
[0025] The components are weighed on Sartorius semi-analytical scales with consequent manual mixing in plastic bags, All the components are introduced into an extruder via K-SFS 24 gravimetric feeding system ex. K-Tron.
[0026] Compounding is performed in a co-rotating twin-screw extruder ZE25 ex Berstorff with L/D=32. The compounding conditions are presented in Table 2. The extruded strands are pelletized in pelletizer 750/3 ex Accrapak Systems Limited.
[0027] The obtained pellets are dried in a circulating air oven ex Heraeus Instruments at 75° C. for 4 hours.
[0000]
TABLE 2
Compounding conditions
PARAMETER
UNITS
Set values
Feeding zone temperature (T 1 )
° C.
no heating
T 2
° C.
160
T 3
° C.
230
T 4
° C.
230
T 5
° C.
230
T 6
° C.
230
T 7
° C.
200
T 8
° C.
230
T 9
° C.
230
Temperature of melt
° C.
230
Screw speed
RPM
300
Injection Molding
[0028] Test specimens were prepared by injection molding in an Allrounder 500 150 ex. Arburg. All test specimens were prepared under the same conditions. The injection molding conditions are presented in Table 3.
[0000]
TABLE 3
Injection molding conditions
PARAMETER
UNITS
Set values
T 1 (Feeding zone)
° C.
180
T 2
° C.
200
T 3
° C.
230
T 4
° C.
230
T 5 (nozzle)
° C.
230
Mold temperature
° C.
40
Injection pressure
bar
500
Holding pressure
bar
250
Back pressure
bar
20
Injection time
sec
0.1
Holding time
sec
10.0
Cooling time
sec
5.0
Mold closing force
kN
500
Filling volume (portion)
ccm
21
Injection speed
ccm/sec
10
Conditioning
[0029] Prior to UL-94 testing test specimens are conditioned at 70° C. for 168 hours and at 23° C. for 168 hours.
[0030] Compositions and flammability test results are presented in Table 4 for HIPS compositions and in Table 5 for ABS compositions.
[0000]
TABLE 4
HIPS compositions and flammability test results
Reference
Reference
Reference
Reference
Reference
Reference
Reference
Reference
Reference
Components
Units
Example 1
example 2
example 3
example 4
example 5
example 6
example 7
example 8
example 9
HIPS Styron 472
%
82.5
81.5
84.4
84.5
83.4
79.2
78.2
81.5
81.6
FR-245
%
17.2
17.2
14.9
14.9
FR-1210
%
13.9
13.9
12.0
12.0
12.0
F-3020
%
Antimony trioxide
%
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
3.5
PTFE Hostaflon 2071
%
0.1
0.1
0.1
0.1
0.1
0.1
0.1
Carbon Black
%
1.0
1
1.0
Bromine calculated
%
11.5
11.5
10
10
10
11.5
11.5
10
10
Flammability UL-94V at 1.6 mm
Max flaming time
sec
2
1
2
4
1
2
1
2
3
Total flaming time
sec
10
9
10
17
10
11
7
12
11
Max after glow time
sec
12
0
0
0
11
20
36
31
0
Max after glow +
sec
13
1
1
1
12
22
36
31
1
after flame time
Specimens dripped
num
0
0
0
3
0
0
0
0
5
Cotton ignition
num
0
0
0
2
0
0
0
0
5
Sample burned up to
num
0
0
0
0
0
0
0
0
0
the holding clamps
Rating
V-0
V-0
V-0
V-2
V-0
V-0
V-1
V-1
V-2
HIPS compositions and test flammability results
Reference
Reference
Reference
Reference
Reference
Reference
example
example
example
example
example
example
Components
Units
10
11
12
13
14
15
Example 1
Example 2
Example 3
HIPS Styron 472
%
80.5
80.8
83.0
81.6
81.2
79.6
81.0
81.5
80.6
FR-245
%
14.9
14.9
14.9
14.9
14-9
10.4
14.9
14.9
10.4
FR-1210
%
F-3020
%
5.4
5.4
Antimony trioxide
%
3.5
3.2
1.0
2.5
2.5
3.5
3.0
2.5
2.5
PTFE Hostaflon 2071
%
0.1
0.1
0.1
0.02
0.4
0.1
0.1
0.1
0.1
Carbon Black
%
1
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
Bromine calculated
%
10
10
10
10
10
10
10
10
10
Flammability UL-94V at 1.6 mm
Max flaming time
sec
1
3
78
6
1
3
2
7
4
Total flaming time
sec
9
13
338
26
7
12
12
16
18
Max after glow time
sec
54
35
0
31
45
35
21
2
22
Max after glow +
sec
55
37
78
33
46
38
22
2
24
after flame time
Specimens dripped
num
0
0
3
0
0
0
0
0
Cotton ignition
num
0
0
3
0
0
0
0
0
Sample burned up to
num
0
0
4
0
0
0
0
0
0
the holding clamps
Rating
V-1
V-1
HB
V-2
V-1
V-1
V-0
V-0
V-0
[0031] Table 4 above summarizes several composition and flammability test results of prior art related fire-retardant formulations as well as of formulations relating to the present invention. From this table it is clearly seen that:
(a) Formulations (Reference Example-6) based on JP 11323064 pass successfully the V-0 flammability test, but introducing 1 wt. % carbon black pigment (Reference Example-7), results in derating to V-1 due to long afterglow time. (b) In fire-retardant FR-1210 (decabromodiphenyl oxide) based formulations—Reference Examples 1-5—the first two formulations substantially having the same bromine, antimony trioxide and PTFE concentrations as in Reference Examples 6 and 7 pass V-0 tests, even when containing carbon black pigment (Reference Example 2). Reducing bromine content to 10 wt. % and then further elimination of PTFE from this formulation result in V-0 and V-2 rating, respectively (Reference Example 3 and Reference Example 4), the latter is due to burning drops ignited cotton effect. Addition of carbon black to Reference Example 3 does not derate the formulation and it passes V-0 tests (Reference Example 5). It should be noted that the antimony trioxide remains essentially unchanged in all those formulation variations. (c) Reference Example 8, Reference Example 9, Reference Example 10 and Example 2 to Example 3 relate to FR-245 containing formulations having varying concentrations of the components Further reduction of FR-245 to 10 wt. % bromine while keeping the antimony trioxide concentration relatively high (Reference Example 8) results in derating to V-1. Omission of PTFE from this formulation (Reference Example 9) results in dripping with cotton ignition and V-2 rating. Further addition of carbon black to Reference Example 8 (Reference Example 10) results in long afterglow effect and a rating of V-1. However, reduction of antimony trioxide to 2.5 wt. % (Example 2) surprisingly improves flammability retardation and is rated V-0. Further reduction of antimony trioxide to 1 wt. % (Reference Example 12) results in total burning of the specimen up to the clamps and in a HB rating. The upper concentration limit of antimony trioxide is tested in Reference Example 11 vs. Example 1; at antimony trioxide concentration of 3.2 wt. % the formulation is rated V-1 because of long after glow time (Reference Example 11); at antimony trioxide concentration of 3.0 wt. % the formulation is rated V-0 (Example 1). The concentration limits of PTFE are tested in formulations Reference Example 13, 0.02 wt. %, and Reference Example 14, 0.4 wt. %. In the first an effect of burning drops ignited cotton leads to V-2 rating. The second is rated V-1 due to long afterglow time. (d) The employment of both FR-245 and F-3020 (MBEO endcapped brominated epoxy resin) as the bromine fire-retardants, the first contributing about 7 wt. % and the second about 3 wt. % of the bromine content, leads to long afterglow time (Reference Example 15) when incorporating 3.5 wt. % antimony trioxide, i.e. V-1 rating, and to successful results (Example 3) when lowering antimony trioxide concentration to 2.5 wt. %, i.e. V-0. These two results are similar to the ones achieved for formulations containing only FR-245, i.e. Reference Example 10 and Example 2, and further stress the optimal relation between bromine fire-retardant and antimony trioxide synergist contents.
[0000]
TABLE 5
ABS compositions and results of flammability results
Reference
Components
Units
example 16
Example 4
ABS Magnum 3404
%
80.0
81.0
FR-245
%
14.9
14.9
Antimony trioxide
%
4.0
3.0
PTFE Hostaflon 2071
%
0.1
0.1
Carbon Black
%
1.0
1.0
Bromine calculated
%
10
10
Flammability UL-94V at 1.6 mm
Max flaming time
Sec
5
7
Total flaming time
Sec
16
29
Max after glow time
Sec
36
21
Max after glow + after
Sec
38
23
flame time
Specimens dripped
Num
0
0
Cotton ignition
Num
0
0
Sample burned up to the
Num
0
0
holding clamps
Rating
V-1
V-0
[0036] Table 5 demonstrates that the same effects, which are observed in HIPS formulations, are also applied in ABS based formulations.
[0037] HIPS and ABS containing fire-retardant formulations containing FR-245 or a combination of FR-245 and BEO's at low bromine content and with the incorporation of carbon black do not pass UL-94 V-0 because of long after glow time. It is surprisingly found that at low antimony trioxide concentrations it is possible to pass UL-94 V-0 and get economic cost-effective formulations with good mechanical, thermal and processing properties.
[0038] While examples of the invention have been described for purposes of illustration, it will be apparent that many modifications, variations and adaptations can be carried out by persons skilled in the art, without exceeding the scope of the claims. | A fire-retardant formulation for styrene-containing polymers comprising tris(2,4,6-tribromophenoxy)-s-triazine (FR-245), antimony trioxide and polytetrafluoroethylene (PTFE), wherein the bromine concentration in said fire-retardant formulation is from about 9.0 to about 10.5 wt. %, said antimony trioxide concentration being lower than about 3.2 wt. %. | 2 |
This invention relates to rotary fluid pressure actuators.
A type of rotary fluid pressure actuator has been known for many years which comprises a cylinder with two pistons, each integral with a rack, the two racks engaging a pinion which extends transversely of the cylinder at the mid-length point of the cylinder. As the pistons move simultaneously either towards or away from one another under the influence of a fluid under super-atmospheric pressure, the pinion is moved angularly about its axis of rotation by said racks. The pistons are not guided on or supported by any rods during their reciprocating movements. Equal torque is said to be produced in each direction of angular movement of said pinion. This type of actuator has been described and illustrated in "Machine Design, Fluid Power" dated Sept. 19, 1968, to quote but one example.
The type of actuator described in the preceding paragraph will hereinafter be referred to as "a rotary actuator of the type described".
A rotary actuator of the type described (as defined above) has an inherent defect in that, in the case of each piston and its integral rack, that end of the piston in which the rack is formed tends to score the cylinder wall during operation of the actuator. The reason for this is very well-known, namely, that the teeth of the rack of each piston tend to ride up the pinion teeth with which they mesh by virtue of the fact that the shaft in which the pinion teeth are cut or to which the gear pinion(s) is or are secured is only free to rotate or move angularly and that the piston is only free to perform rectilinear movements. The separating force which causes the rack teeth to ride up the pinion teeth is known to be greater when the pistons are moved towards one another than it is when they are moved away from one another, and of course, the piston itself becomes scored as it scores the cylinder wall.
Naturally, a part of the available power is wasted in overcoming the friction developed as the rack-bearing end of each piston rubs along the cylinder wall. Moreover, if the scoring of the cylinder wall becomes sufficiently severe (as it does eventually), not only is there the danger of the O-ring or other seal carried by the full-diameter part of the piston failing to seal against the cylinder wall, but also there is the danger of the scored metal tearing the O-ring or other seal and eventually rendering it useless for its purpose.
The primary object of the present invention is to overcome these defects.
According to a first aspect, the present invention consists in a rotary actuator of the type described (as defined above) wherein, in the case of each piston, that part of the piston in which the rack is provided carries an element or elements which is or are made of an elastomeric or synthetic resin material having a low coefficient of friction and which is or are so placed as to be in contact with the adjacent portion of the cylinder wall at all times, whereby the separating forces are counteracted which are generated by movement of said pistons towards or away from one another and which tend to displace said part of each of said pistons towards the cylinder wall.
If one element is employed, said element will preferably be accommodated in and project radially from a channel formed in the curved periphery of said part of the piston, which periphery may have a curvature matching that of said adjacent portion of the cylinder wall.
If two or more elements are employed, each will preferably be accommodated in and project radially from an equal number of housing cavities or recesses which are formed in the curved periphery of said part of the piston, which periphery may have a curvature matching that of said adjacent portion of the cylinder wall.
Said channel, and said housing cavities or recesses, may extend or be aligned, respectively, circumferentially of said curved periphery or axially of said piston or along a part-helical path. One convenient arrangement which would provide a circumferential channel or channels would be to make said part of the piston in such a manner that a portion of its free end (viz. the end remote from the full-diameter part of the piston) is removably securable to the remainder of said part of the piston in which the rack is provided, the abutting faces being appropriately cut away to create a channel of a cross-sectional shape such as to enable one or more than one element to be positively held in said channel or channels.
According to a second aspect, the present invention consists in a rotary actuator of the type described (as defined above) wherein the cylinder carries an element or elements which is or are made of an elastomeric or synthetic resin material having a low coefficient of friction and which is or are so placed as to be in contact at all times with the curved outer periphery of that part of each piston in which said rack is provided.
Said element may extend circumferentially (viz. its median line will be contained in a diametral plane of said cylinder), or, in the case of two or more elements being carried by the cylinder, said elements may extend axially of the cylinder or in part-helical paths along said cylinder.
If the pinion output shaft of the actuator according to either of the first and second aspects of the present invention is provided with two sets of teeth, one set being spaced from the other set along the axis of the output shaft, said output shaft will preferably carry an annulus which
(a) is made of an elastomeric or synthetic resin material having a low coefficient of friction; and
(b) is of a diameter such as will contact a flat runway which is provided on said part of each of said pistons and which divides the rack teeth on each of said pistons into two spaced sets of teeth; whereby said annulus in contact with the opposed runways on the pistons will, during operation of the actuator, positively maintain contact between said elements or element and the metal parts or part concerned and will positively maintain correct meshing of the teeth of the racks and the pinion.
Alternatively, in the case where the pinion output shaft has a set of teeth which is uninterrupted axially of the shaft, said shaft will carry axially spaced annuli each of which
(a) is made of an elastomeric or synthetic resin material having a low coefficient of friction; and
(b) is of a diameter such as will contact one of two spaced flat runways which are provided on said part of each of said pistons;
whereby said annuli in contact with the opposed runways on the pistons will, during operation of the actuator, positively maintain contact between said element or elements and the metal part or parts concerned and will positively maintain correct meshing of the teeth of the racks and the pinion.
The present invention will now be more particularly described with reference to the accompanying drawings, in which:
FIG. 1 represents, schematically, an axial section of a preferred embodiment of a rotary fluid pressure actuator according to the present invention;
FIG. 2 represents a transverse section through the actuator illustrated in FIG. 1 on the line A--A thereon;
FIG. 3 is a perspective view of a cylinder having a plurality of radial bearing strips;
FIG. 4 is a perspective view of a cylinder having a plurality of axial bearing strips;
FIG. 5 is a perspective view of a piston having a helical bearing strip;
FIG. 6 is a perspective view of a piston and an output shaft showing end guide rollers which contact associate axial guide strips;
FIG. 7 is a perspective view of a cylinder and an output shaft having a central roller guide which contacts a central axial guide strip;
FIG. 8 is a diagramatic perspective view of the cylinder having a plurality of axial bearing strips;
FIG. 9 is a diagramatic view of a perspective of the cylinder having a plurality of circumferential bearing strips.
DETAILED DESCRIPTION
Referring to the drawings, there is illustrated therein a rotary actuator of the type described (as defined above) which comprises a cylinder 10 whose open ends are closed by end caps 11, 12. An output shaft 13 extends transversely of the cylinder 10 in such a manner that its axis of rotation is contained by a diametral plane which is normal to the longitudinal axis of said cylinder and in such a manner that said axis of rotation extends through the mid-length point of said longitudinal axis. End portions 14, 15 of said shaft 13 are journalled in the cylinder 10, and said shaft 13 is also provided at one end thereof with a projecting boss 16 of non-circular cross-sectional shape and at the other end thereof with a recess 17 of square cross-sectional shape.
Said shaft 13 further includes teeth 18 which form a center gear, the teeth 18 on opposite sides of said center gear being in mesh with the teeth of two racks 19 which are integral with two pistons 20. The pistons 20 are of course of a circular configuration and size commensurate with those of the inside surface of the cylinder 10, and the periphery of each piston is so formed as to accommodate an O-ring seal 21 and a piston bearing 22 which is split to facilitate the fitting thereof to the piston. The racks 19, on the other hand, are constituted by axially extending members each of which is joined at one end thereof to the associated piston and each of which terminates at the other end thereof in a radially extending portion 23 which is so formed as to accommodate a guide bearing 24, each of said members incorporating at least one stiffening web 25 so as to strengthen the connection between the piston 20 and the associated portion 23.
The end caps 11, 12 are provided with inlet/exhaust ports 26, 27 and the cylinder 10 is provided with a centrally positioned inlet/exhaust port 28. These various ports are provided for the purpose of supplying a fluid under super-atmospheric pressure to the appropriate piston faces and exhausting used pressurised fluid from the other piston faces in order to obtain the required angular movement of the shaft 13 in known manner.
O-ring seals are provided, as illustrated, in other places in the usual way, namely, at the journals of the shaft 13 and between each end cap and the relevant end of the cylinder 10.
The boss 16 is provided to enable a human operator, equipped with an appropriate tool, to move the shaft 13 angularly as desired, for example, in the case of failure of the pressurised fluid line. The recess 17, or any other mechanical equivalent thereof, is provided for the connection of the shaft 13 to the valve or other apparatus which is to be operated by the actuator.
Although not actually illustrated in FIG. 2 of the drawings, bearings will be provided at the journals of the shaft 13 and said bearings will be positioned axially outwardly of the O-ring seals which are illustrated in FIG. 2. Besides being provided to cater for the tooth separating forces generated between the teeth 18 of the center gear and the teeth of the racks 19 when the pistons are moved towards or away from one another, the bearings referred to in the preceding sentence are necessary also to cater for any slight misalignment due to manufacturing tolerances; said bearings permit the misalignment to be made good with the result that the center gear will be equally driven by said racks.
The preferred material for the guide bearings 24 is an acetyl resin (for example DELRIN, Registered Trade Mark) which wears well, possesses good compressive stress characteristics, and has a low coefficient of friction.
The preferred embodiment of the present invention has been illustrated in the drawings and has been described above. However, the invention is not to be interpreted as limited only to such embodiment. As described earlier in this specification, other mechanical equivalents (such as strips of DELRIN carried by the cylinder instead of by the portion 23) are to be considered as falling within the scope of at least some of the appended claims. As indicated above, FIG. 3 shows a perspective view of a piston having a plurality of radial bearing strips, and FIG. 4 shows a piston having a plurality of axial bearing strips. FIG. 5 shows a piston having a helical bearing strip. FIG. 6 shows a piston and an output shaft wherein the output shaft is provided with a pair of end guide rollers which contact axial guide strips on the piston. FIG. 7 shows a piston and an output shaft wherein the output shaft is provided with a central roller guide which contacts an axial central guide strip on the piston. FIG. 8 is a diagramatic view of a cylinder having a plurality of axial bearing strips. FIG. 9 is a diagramatic view of another cylinder having a plurality of circumferential bearing strips. | A piston rack rotary actuator, devoid of guiding tubes or rods along which the pistons reciprocate, is provided with guide bearings which eliminate or at least reduce the incidence of the separating forces which otherwise act on the racks (particularly when the pistons are moved towards one another) to displace them towards the cylinder wall and which thereby otherwise cock the pistons in the cylinder and cause scoring of the cylinder wall. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority to Korean Patent Application Number 10-2010-0029200 filed Mar. 31, 2010, the entire contents of which application is incorporated herein for all purposes by this reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the structure of an automatic transmission equipped with a vehicle, and more particularly to a valve body cover of an automatic transmission.
2. Description of Related Art
The valve body of automatic transmission is a device that can control the operation of the automatic transmission, using hydraulic pressure, which is disposed in a transmission case of the automatic transmission and of which the outer side is covered and protected by a valve body cover mounted on the transmission case.
The valve body cover is provided with an oil level plug to check whether an appropriated amount of oil exists in the transmission case.
In the related art, a nut is welded where the oil level plug is mounted in valve body covers made of metal and a nut is inserted in valve body covers made of plastic, in order to mount the oil level plug, which is a bolt type, in the nut with predetermined torque.
Theses structure, however, had a problem that the nut is likely to separate from the valve body cover after a long time and additional works are required due to inserting or welding the nut in manufacturing the valve body cover, such that the manufacturing cost increases and the weight is increased by the metal nut.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
BRIEF SUMMARY OF THE INVENTION
Various aspects of the present invention are directed to provide a valve body cover of an automatic transmission that makes it possible to reduce the manufacturing works, the manufacturing cost, and the weight, and improve durability, by mounting an oil level plug without additionally inserting or welding a nut.
In an aspect of the present invention, the valve body cover of an automatic transmission may include a cover plate having a hole; an oil level plug having a cap detachably mounted onto the cover plate from the outside of the cover plate and an insertion extended from the cap and selectively inserted into the hole of the cover plate; and rotational pressing members formed in the insertion of the oil level plug and the cover plate respectively to press the cap against the cover plate while the insertion of the oil level plug inserted in the hole may be rotated relatively with respect to the cover plate.
The valve body cover of the automatic transmission may further include a sealing member which may be disposed between the cap and the cover plate and compressed by the cap for sealing a gap formed between the cap and the cover plate while the cap may be rotatably coupled to the cover plate, wherein the sealing member may be formed in a ring to be fitted around the insertion, wherein the cover plate includes a receiving groove formed along the hole of the cover place to retain the sealing member therein, and wherein a locking protrusion may be formed on an inner circumference of the receiving groove to couple the sealing member in the receiving groove.
The rotational pressing members may include a locking protrusion disposed with a predetermined distance from the cap in a longitudinal direction of the insertion and protruding from the insertion radially from the longitudinal direction of the insertion; a receiving hole formed in the cover plate and extending from the hole of the cover plate outwards so as to allow the locking protrusion of the insertion to pass through the receiving hole at a predetermined position of the cover plate; and a spiral protrusion spirally protruding from the cover plate toward the inside of the cover plate such that the locking protrusion passing through the receiving hole moves toward the inside of the cover plate in the longitudinal direction of the insertion while the locking protrusion of the insertion rotates along the spiral protrusion.
The spiral protrusion may spirally protrude from the cover plate toward the inside of the cover plate with a predetermined slope with respect to the cover plate along a circumferential direction of the hole.
The valve body cover of the automatic transmission may include a rotation range restricting member that may be disposed between the oil level plug and the cover plate to restrict a rotation of the oil level plug rotating with respect to the cover plate within a predetermined range such that the locking protrusion of the insertion spirally move along the spiral protrusion with the predetermined slope and may be mounted to the spiral protrusion, wherein the rotation range restricting member has a restricting leg protruding from the cap with a predetermined length; and an arc locking slot formed on the cover plate such that the restricting leg may be inserted and locked therein to mount the locking protrusion onto the spiral protrusion, wherein the rotation range restricting member further includes an arc guide slot which may be integrally formed to one end portion of the arc locking slot, wherein a ridge portion may be formed between the arc guide slot and the arc locking slot to make a thickness of the arc guide slot smaller than the thickness of the arc locking slot, and wherein the restricting leg may be elastically biased against the ridge portion of the arc guide slot such that the restricting leg sliding along the arc guide slot may be locked into the arc locking slot when the restricting leg passes over the ridge portion into the arc locking slot.
The cap may be formed in a circular plate and the restricting leg protrudes downwards from an outer circumference of the cap toward the cover plate with the predetermined length.
A tool groove may be formed approximately at the center of the cap to insert a tool thereto and apply a rotational force to rotate the oil level plug with respect to the cover plate.
The present invention has a structure that makes it possible to combine or separate an oil level plug with or from cover plate itself of a valve body cover, without additionally inserting or welding a specific nut. Therefore, it is possible to reduce manufacturing works and manufacturing cost of a valve body cover of an automatic transmission and also reduce the weight and improve durability with stable sealing, by changing the structure of the oil level plug.
The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a showing a valve body cover of an automatic transmission according to the present invention.
FIG. 2 is a view showing in detail the main parts that are exploded of FIG. 1 .
FIG. 3 is a view showing the oil level plug of FIG. 2 .
FIG. 4 is a view comparing the inner side and the outside around a hole of a cover plate.
FIG. 5 is a cross-sectional view illustrating the operation the oil level plug mounted on the cover plate.
FIG. 6 is a view illustrating the process of mounting the oil level plug to the cover plate.
It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.
In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.
DETAILED DESCRIPTION OF THE INVENTION
Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.
Referring to FIGS. 1 to 4 , a valve body cover of an automatic transmission according to an exemplary embodiment of the present invention includes a cover plate 3 having a hole 1 and mounted to a transmission case to cover a valve body, an oil level plug 9 having a cap 5 mounted to be positioned outside cover plate 3 and an insertion 7 that is inserted into hole 1 from cap 5 , a rotational pressing member formed in oil level plug 9 and cover plate 3 to gradually move cap 5 to cover plate 3 when oil level plug 9 is rotated relatively to cover plate 3 , with insertion 7 in hole 1 , and a sealing member 11 compressed between cap 5 and cover plate 3 for sealing, when cap 5 is moved to cover plate 3 .
That is, the portion implemented by a nut in the related art is integrally formed with cover plate 3 and oil level plug 9 that was a bolt type in the related art is modified, such that oil level plug 9 is assembled and disassembled only by one rotation at the most with respect to cover plate 3 .
It is preferable that cover plate 3 is made of plastic to achieve the complicate shape around hole 1 at one time by injection molding and oil level plug 9 assembled with it may be made of similar plastic.
In the present embodiment, the rotational pressing member includes locking protrusions 13 protruding radially from insertion 7 , receiving holes 15 extending from hole 1 of cover plate 3 to allow locking protrusions 13 to pass through the receiving holes 15 at predetermined positions, spiral protrusions 17 spirally protruding toward the inside of cover plate 3 such that locking protrusions 13 passing through receiving holes 15 can move toward the inside of cover plate 3 while rotating with cover plate 3 .
Therefore, when insertion 7 is inserted in hole 1 , with locking protrusion 13 positioned to pass through receiving holes 15 , and the cap 5 is rotated, as shown in FIG. 5 , locking protrusions 13 spirally moves along spiral protrusions 17 and cap 5 moves to cover plate 3 .
An exemplary embodiment of the present invention may include a receiving groove 20 formed in the cover plate 3 around the hole 1 and receive a sealing member 11 therein. The receiving groove 20 may include at least a locking protrusion 22 on the inner circumference thereof to retain the sealing member 11 firmly.
In this operation, the sealing member 11 is pressed by the movement of cap 5 between cap 5 and cover plate 3 to seal the space between cap 5 and cover plate 3 , thereby preventing oil inside cover plate 3 from leaking outside.
In the present embodiment, sealing member 11 is formed in a ring fitted around the insertion 7 , as shown in FIG. 2 to seal the entire circumference of insertion 7 of oil level plug 9 without a gap between insertion 7 and cover plate 3 .
Sealing member 11 may be made of the same materials of common sealing parts of the related art, such as rubber or urethane.
In the present embodiment, a rotation range restricting member that restricts the rotation of oil level plug 9 rotating with respect to cover plate 3 within a predetermined range such that locking protrusions 13 spirally move along spiral protrusions 17 is disposed between oil level plug 9 and cover plate 3 .
The cover plate 3 includes an arc guide slot 23 . The rotation range restricting member has restricting legs 19 protruding from cap 5 to cover plate 3 through the arc guide slot 23 formed to guide the rotational movement of the restricting legs 19 and the arc locking slots 21 formed an end portion of the arc guide slot 23 on cover plate 3 such that restricting legs 19 are inserted and locked therein after a predetermined rotation along the arc guide slot 23 .
In an exemplary embodiment of the present invention; the arc guide slot 23 includes a ridge portion 27 such that the thickness of the arc guide slot 23 is smaller than the thickness of the arc restricting slot 21 . The restricting leg 19 is elastically biased toward the insertion 7 such that when the restricting legs 19 rotates into the arc locking slots 21 over the ridge portion 27 , the restricting leg 19 is snapped thereto.
Cap 5 is formed in a circular plate, restricting legs 19 protrude downward from the outer circumference of circular plate-shaped cap 5 to cover plate 3 , and a tool groove 23 is formed at the center of cap 5 to insert a tool and apply rotational force.
Therefore, referring to FIG. 6 , when insertion 7 is inserted in hole 1 , with locking protrusions 13 aligned with receiving holes 15 , the position shown at the upper portion of FIG. 6 is achieved, and then, as it is rotated by inserting an appropriate tool in tool groove 23 , as shown at the lower portion in FIG. 6 , restricting legs 19 rotate and stop within the allowable range of arc locking slots 21 . Accordingly, sealing member 11 between cap 5 and cover plate 3 is sufficiently pressed by the rotation and desired sealing is sufficiently achieved.
Meanwhile, tool groove 23 on cap 5 may be modified in a common hex wrench groove or groove that a driver can be inserted in, other than the rectangular groove shown in the figure.
For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner” and “outer” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. | A valve body cover of an automatic transmission, may include a cover plate having a hole, an oil level plug having a cap detachably mounted onto the cover plate from the outside of the cover plate and an insertion extended from the cap and selectively inserted into the hole of the cover plate, and rotational pressing members formed in the insertion of the oil level plug and the cover plate respectively to press the cap against the cover plate while the insertion of the oil level plug inserted in the hole is rotated relatively with respect to the cover plate. | 5 |
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of application Ser. No. 08/284,896 filed on Aug. 2, 1994, now U.S. Pat. No. 4,452,933.
FIELD OF THE INVENTION
The present invention pertains to an exterior sun visor which is mountable to a vehicle above the vehicle's front windshield.
BACKGROUND OF THE INVENTION
Exterior sun visors that can optionally be mounted to vehicles are known. Such visors are currently sold in the vehicle accessory market. Increasingly, these are sold as plastic component kits attachable either by dealers or by the ultimate customer. These lightweight visors replace those that were sold perhaps 30-50 years ago as original option accessories with the vehicle.
While lightweight, attractive visors have their desirable features, they also have some inherent problems. First, because the visor is located on the forward portion of the vehicle just above the windshield, it necessarily is subject to extreme wind forces. As a result, if they are improperly constructed or improperly mounted, extreme vibration will occur. This extreme vibration is not only annoying to the vehicle driver, but also may eventually cause damage to both the visor and the vehicle cab, especially at the point of attachment of the visor to the cab.
Since one of the primary purposes of a visor is to shield the driver's eyes from sun, it necessarily follows that a desirable feature is the use of a translucent material on at least a portion of the visor so that it shields the driver's eyes in similar fashion that sun glasses do. This feature particularly involves the use of an additional type of material, different from that of the visor frame. While the shading for the driver's eyes is a nice feature, the use of two or more materials to form the visor composite compounds problems caused by high wind velocity, since the multicomponents sacrifice structural integrity. As a result, wind velocity may often damage, destroy or pull away a shaded visor insert.
One way that the prior art has solved the structural integrity problems is to utilize a visor which has a rigid interior steel frame, the theory being that this steel frame will make it more rigid to withstand the wind velocity to avoid vibration problems. However, this use of such a steel frame drastically increases cost, and the increased weight will exacerbate vibration damage, if and when the unit vibrates.
It can therefore be seen that there is a real and continuing need for the development of a lightweight, economical, easy-to-install visor.
The primary objective of the present invention is to develop the needed lightweight, economical, easy-to-install, and structurally strong visor.
Another objective of the present invention is to prepare a visor insert which, because of its streamlined and contoured shape, as well as its integrated structure, avoids normally attendant vibration problems.
Another objective of the present invention is to provide a windshield visor which can use a visor insert, but which avoids potential damage to the insert caused by wind velocity.
Another objective of the present invention is to provide a hollow interior visor frame, preferably of a multicomponent hollow monocoque frame. These and other objectives will become apparent from the detailed description of the invention which follows.
A yet further objective is to provide a visor which has no exposed edges, and the mating surface matches the contour of the vehicle in a flush manner.
Another objective of the present invention is to provide a windshield visor that has running lights formed on it.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a vehicle with the windshield visor embodying the present invention attached.
FIG. 2 is a side elevational view of the vehicle along line 2--2.
FIG. 3 is a plan view of the visor.
FIG. 4 is a perspective view of the visor.
FIG. 5 is an exploded view showing how the visor components fit together for securement to the cab of a vehicle.
FIG. 6 is a sectional view along line 6--6 of FIG. 5.
FIG. 7 is a sectional view along line 7--7 of FIG. 5.
FIG. 8 is a plan view with parts broken away showing how the visor frame is attached to the vehicle.
FIG. 9 is a sectional view along line 9--9 of FIG. 8.
FIG. 10 is a perspective view of the visor including five running lights.
FIG. 11 is an exploded view taken from line 11--11 in FIG. 10 showing how the light fixtures fit together with the visor.
FIG. 12 is a plan view of a light fixture with the lens removed.
FIG. 13 is a sectional view along line 13--13 of FIG. 11.
FIG. 14 is a sectional view along line 14--14 of FIG. 12.
FIG. 15 is a sectional view along line 15--15 of FIG. 14.
FIG. 16 is a perspective view of the back of the light fixture showing how it plugs into the wiring.
SUMMARY OF THE INVENTION
The present invention pertains to a windshield visor that may be sold in a kit for the vehicle accessory market. It preferably is comprised of a multicomponent hollow monocoque frame which defines an upper insert area to which a translucent visor insert can matingly fit and be bonded thereto, preferably by a pressure sensitive adhesive bonding strip. A number of running lights can be formed in the visor. The entire unit is structurally strong, of integrated, streamlined shape, lightweight, and avoids vibration problems.
DETAILED DESCRIPTION OF THE INVENTION
With continuing reference to the drawings, the visor 10 may be mounted to a vehicle cab 11 as illustrated in FIG. 1. The visor 10 is comprised of a visor frame 12 having a first outer end 16 and a second outer end 18. Visor outer ends 16 and 18 have a series of apertures 19 for use in securement of the visor frame 12 to the vehicle cab 11.
Visor frame 12, in addition to first outer end 16 and second outer end 18, may have a midpoint brace 14, also having apertures 19. Midpoint brace 14 is optional. It may or may not be used, but when used provides additional strength.
Visor frame 12 has a forward or leading edge 20. Visor frame 12 extends rearwardly from forward edge 20 in both a rearward and upward manner as depicted to a rear edge 21, dropping downwardly to define a rear shoulder 22. The drop from rear edge 21 to rear shoulder 22 defines an insert area 24.
The windshield visor frame 12 is preferably a multicomponent hollow monocoque frame which is ideally comprised of a thermoset plastic reinforced with woven fiberglass, with the thermoset plastic preferably being either polyester or polyurethane. As best seen in FIGS. 6 and 7, monocoque frame has cardboard insert 26 formed and fit during the molding process. Placed over the insert 26 is the resinous bottom material 28. In this way, strength is substantially increased in a lightweight structure.
Insert area 24 is adapted so that it may matingly hold, in conforming relationship, a translucent visor insert 30. Visor insert 30 may be made of translucent acrylic or Lexan®. Any suitable translucent plastic material will work. Visor insert 30 is bonded to visor frame 10 adjacent the inner edges of the insert area close to rear shoulder 22. As illustrated, a cushioned adhesive strip 32 is laid adjacent rear shoulder 22, and the visor insert 30 pressed downwardly against the adhesive strip to securely hold it. Because visor insert 30 is of a conforming and mating relationship with the insert area 24, it does not destroy the overall streamlined contour defined by forward edge 20, and the rearwardly extending portion of the frame towards rear edge 21. In this way, wind is deflected up and over without the potential of ripping visor insert 32 away from visor frame 10.
Bolts 34 are, of course, inserted into apertures 19 and into the cab 11 of the vehicle, using expandable anchors 36. These are, of course, inserted and secured before the visor insert 30 is bonded to the visor frame. As can be seen best in FIGS. 6 and 7, the interior of the visor frame is hollow, and if desired, may be used, for example, for interior mounting of visor lights, etc. The unit is lightweight, and has all the advantages of previously used shaded visors without sacrificing structural integrity. It can also be used with a minimum of wind-caused vibration problems.
The visor frame 12 may have a number of snap-in running lights 40 formed on the frame as illustrated in FIG. 10. The running lights 40 are each comprised of a housing 42, a bulb 44, a PVC gasket 46 and a lens 48 as shown in FIG. 11. The running lights 40 are inserted in apertures 52 which are formed in the visor frame 12 of the present invention. Each running light 12 includes 4 securement tabs 50 as shown in FIGS. 11-16. The securement tabs 50 are preferably made from a resilient material and include a plurality of locking members 51 on one side (FIG. 15). The tabs 50 are normally biased outward from the housing 42. When each running light 40 is inserted through the aperture 52, the securement tabs 50 press against the aperture 52 and come into engagement with the inside surface of the visor frame 12 as shown in FIG. 15. The locking members 51 help to secure the light 40 in place. The securement tabs 50 prevent the light fixture 40 from coming out of the visor frame once it is inserted. When each running light 40 is inserted into the aperture 52, the gasket 46 is disposed between the visor frame 12 and the lens 48. This ensures a moisture proof seal.
A power supply wire 54 is provided inside the visor frame for providing power to the bulbs 44. As shown in FIG. 16, before the running lights are inserted in the aperture 52, a wiring plug 56 is connected to the light fixture contacts 58 to provide power to the bulb 44. After this connection is made, the running light assembly can be inserted through the aperture 52.
The bulbs 44 used with the present invention are preferably bulbs that can be snapped in or out as opposed to conventional socket type bulbs. These snap-in bulbs 44 have a lower profile, are simpler, and are less expensive than conventional socket bulbs. When the insertion of the running lights 40 is complete, there are no visible fasteners holding the light fixture in place. Also, the lights 40 have a low profile so that they can conform to the shape of the frame 20 (FIG. 13).
It can therefore be seen that the invention accomplishes at least all of its stated objectives. | A windshield visor which has a visor frame, a plurality of running lights formed on the visor frame, a translucent insert which fits within the visor frame, bonding member positioned between the translucent insert and the visor frame, and which preferably has the translucent visor insert in conforming relationship to the visor frame structure, and fitting wholly over all fastening means. In a preferred embodiment, the visor frame is a multicomponent, hollow monocoque frame. | 1 |
The present invention relates to manufacturing parts made of ceramic matrix composite (CMC). More precisely, the invention relates to a method of manufacturing CMC parts, the method being of the type comprising making a fiber preform which is then consolidated by being impregnated by means of a liquid, and with the consolidated preform then being densified.
BACKGROUND OF THE INVENTION
Together with carbon/carbon composites, CMCs are thermostructural composite materials that are characterized by good mechanical properties that make them suitable for building structural elements, and by their ability to retain these mechanical properties up to high temperatures.
Thermostructural composites are used in particular in aviation and in space applications, and in particular for making parts of aircraft engines, or structural elements of space vehicles.
The manufacture of a part made of composite material generally comprises making a fiber preform to a shape that is close to that of the part to be manufactured, and then in densifying the preform with the matrix.
The fiber preform constitutes the reinforcement of the part to which it essentially confers its mechanical properties. The preform is obtained from fiber products such as thread, cloth, felt, etc. Shaping is performed by reeling, weaving, stacking two-dimensional plies of cloth or sheets of cables, . . .
Densification of the fiber preform with the matrix consists in filling the pores of the preform throughout its volume with the material that constitutes the matrix.
A first densification technique uses a liquid and consists in impregnating the preform with a liquid mixture that contains a precursor of the matrix material and then, optionally after drying and curing, in subjecting the impregnated preform to heat treatment in order to transform the precursor. Several consecutive cycles of impregnation and of heat treatment are generally necessary in order to achieve the desired degree of densification.
A second densification technique consists in infiltrating the preform with the material from which the matrix is made by chemical vapor infiltration (CVI). To this end, the preform is placed in an infiltration oven into which a gas is admitted. Under determined conditions of temperature and pressure, the gas penetrates into the core of the preform and, on contact with the fibers, the matrix material is formed by the gas decomposing or by component parts of the gas reacting.
In order to enable the fiber preform to retain the desired shape while chemical vapor infiltration is taking place, it is necessary at least during a first portion of the densification process, to hold the preform in tooling, generally made of graphite. Such solid tooling is expensive to make, in particular when the preform is complex in shape. It also needs to have numerous holes machined therein in order to provide the gas with access to the preform through the tooling. In addition, the tooling is heavy and bulky.
Unfortunately, chemical infiltration is a process that is generally very lengthy and very expensive. For example, a densification process typically requires several hundreds of hours. In addition, tooling that occupies an appreciable fraction of the working volume of the infiltration oven and having significant thermal inertia constitutes a drawback. Furthermore, matrix material is inevitably deposited on the tooling, with the consequence of large numbers of rejects due to the preform adhering to the tooling. Even in the best of cases, such deposits require the tooling to be renewed frequently.
Tooling is required during chemical vapor infiltration only until the preform has been consolidated. This stage is reached when a sufficient quantity of the matrix-forming material has been deposited to bond the fibers together throughout the volume of the preform so that after the tooling is removed the preform remains in the desired shape and can be handled. Densification can then be completed with the preform free from tooling. The tooling is nevertheless necessary during at least a portion of infiltration, and infiltration must be interrupted in order to enable the tooling to be withdrawn once the preform has been consolidated.
It is therefore desirable to be able to perform the entire chemical vapor infiltration process without it being necessary to hold the preform in tooling.
When the composite material has a carbon matrix, it is possible, prior to chemical vapor infiltration, to consolidate the preform by means of a liquid. The preform is impregnated with a precursor of carbon, e.g. a resin having a high coke content. The impregnated preform while held in tooling, also known as a "shaper", is dried so as to eliminate any solvent, and then the carbon-precursor resin is polymerized (cured) and heat treatment is performed to cause pyrolysis of the precursor and to leave a carbon residue that consolidates the preform.
An analogous consolidation technique could be devised for use with CMC. However, tests performed by the Applicant in which a fiber preform is consolidated by being impregnated by means of a liquid constituting a precursor of an organosilicon type ceramic, in particular polycarbosilane (PCS) as a precursor for silicon carbide (SiC), by using the conventional methods for cross-linking such precursors, have not given satisfaction.
CMC parts have been made from fiber preforms made of carbon or of silicon carbide, consolidated by being impregnated with a PCS solution, dried, cross-linked by the oxygen in the air, and heat treatment, and the consolidated preforms were densified by chemical vapor infiltration using silicon carbide. Parts made in this way demonstrate mechanical properties that are considerably less good than those obtained when consolidation is performed by chemical vapor infiltration.
This deterioration in mechanical properties appears to stem from the technique used for cross-linking the PCS. Uniform cross-linking throughout the volume of the preform is practically impossible to obtain, in particular when the preform is thick. As a result, a cross-linking gradient exists and zones may even be present where the PCS is not cross-linked, i.e. where it has not been made unmeltable, and as a result it takes up the liquid state during the heat treatment. Furthermore, it is necessary to use very strong tooling for holding purposes in order to counter substrate deformation due to the production of volatile species during pyrolysis. In addition, the presence of oxides in the ceramic residue runs the risk of putting a limit on the refractory properties of the CMC.
Other known techniques for cross-linking PCS, such as cross-linking by means of sulfur or by electromagnetic radiation, or by electron beam process, or by plasma treatment, cannot give satisfaction either, even if the inclusion of oxygen into the ceramic residue is avoided.
Sulfur may constitute a source of pollution. Use of radiation generally leads to long-duration treatment and, like electron beam process, requires an installation that is cumbersome and expensive. Finally, plasma treatment also requires an expensive installation and is effective over a limited thickness only.
An object of the present invention is thus to provide a method of manufacturing CMC parts in which the preform can be consolidated by liquid impregnation using a ceramic precursor, prior to being densified by means of a liquid or by means of chemical vapor infiltration, while avoiding the above-mentioned drawbacks, and without degrading the mechanical properties of the resulting parts.
SUMMARY OF THE INVENTION
According to the invention, this object is achieved by the fact that the impregnation for the purpose of consolidating the fiber preform is performed by means of a thermosetting impregnation composition containing a ceramic precursor, and the consolidation of the preform is obtained by heat treatment at the end of which the precursor is transformed into ceramic without passing through a meltable phase.
The impregnation composition is advantageously constituted by a mixture of a thermosetting monomer and a ceramic-precursor polymer. The monomer is cross-linked during the heat treatment, thereby achieving "in situ" cross-linking of the polymer mixture prior to transformation of the precursor into ceramic. It is important to observe that the polymer mixture is cross-linked uniformly throughout the volume of the preform, regardless of the thickness thereof.
The impregnation composition may further include an accelerator for accelerating cross-linking of the thermosetting monomer.
In an implementation of the invention, the ceramic precursor is an organosilicon polymer such as PCS, a precursor for SiC, while the thermosetting monomer is an acrylic monomer. It is then possible to use dicumyl peroxide as an accelerator for adding to the impregnation composition to accelerate cross-linking of the monomer.
The acrylic monomer is selected from those possessing a solvent in common with the organosilicon polymer. It is also preferable for the resulting acrylic polymer to have a coke content that is as low as possible in order to avoid leaving any significant quantity of carbon residue after pyrolysis.
Three-function monomers constituted by trimethylol propane trimethacrylate (TMPTMA) and trimethylol propane triacrylate (TMPTA) are suitable for this purpose, their coke contents being respectively 2% and 5% by weight.
Other multi-function acrylic monomers may be used, such as ethoxy acrylates, isocyanurate acrylates, erythritol acrylates, and epoxy acrylates, for example.
When the ceramic precursor is PCS and when it is associated with an acrylic monomer such as TMPTMA or TMPTA, the solvent used for making the liquid impregnation composition is selected, for example, from hexane and 1,1,1-trichloroethane (TCE).
DETAILED DESCRIPTION
Examples of the method of the invention for manufacturing parts made of SiC matrix composite material are described below by way of non-limiting indication.
In the examples, the impregnation composition is constituted by PCS and TMPTMA, in solution in TCE or in hexane, together with dicumyl peroxide as an accelerator of TMPTMA cross-linking. The respective quantities by weight of PCS and of TMPTMA in the impregnation composition lie in the range 80/20 to 40/60, and are preferably about 60/40. The concentration of the dicumyl peroxide is about 2% to 3% by weight relative to the weight of the TMPTMA.
EXAMPLE 1
In this example the preform is impregnated for consolidation purposes after it has been shaped.
The preform is made by cutting out plies of cloth, by stacking the plies, and by inserting the stack of plies in shaping tooling to impart the desired shape and fiber fraction to the preform (where fiber fraction is the percentage of the apparent volume of the preform that is actually occupied by fibers).
While the preform is held in the tooling, a thin coating of carbon is deposited on the fibers for the purpose of constituting an interphase between the fibers of the preform and the ceramic material of the matrix. The carbon interphase may be constituted by a resin coke, as described in U.S. Pat. No. 4,748,079, or by pyrolytic carbon obtained by chemical vapor infiltration, as described in U.S. Pat. No. 4,752,503.
An impregnation composition is prepared by dissolving 60 parts by weight (pbw) of coarsely ground PCS in 90 pbw of TCE. After complete dissolution, 40 pbw of TMPTMA and 0.80 pbw of dicumyl peroxide are added.
The preform, held in its tooling and provided with the carbon interphase, is placed in an enclosure where a vacuum is established prior to the impregnation composition being inserted therein.
Following impregnation and returning to atmospheric pressure, a drying step is performed in an oven at around 80° C. to cause the solvent to completely evaporate, leaving an homogeneous translucent phase or "gel".
The TMPTMA is then cross-linked in the oven by raising the temperature of the preform to 90° C. for a period of 1 hour, and then to 120° C. or even 150° C. for a period of one and a half hours.
While the preform is still held in its tooling, it is subjected to pyrolysis heat treatment in a furnace under an inert atmosphere (nitrogen sweeping). During the heat treatment, the temperature is raised progressively to 900° C. during a period lying in the range 40 hours to 130 hours, so as to transform the unmeltable polymer mixture into SiC.
After heat treatment, the preform consolidated by the SiC from the PCS is withdrawn from the tooling and is placed in an SiC infiltration furnace to be densified by chemical vapor infiltration, e.g. as described in patent FR 2 401 888. Densification is continued until the residual porosity lies in the range 10% to 15%.
Table I below gives the results of tensile tests performed on parts A and B manufactured in this way, respectively from a preform made of carbon fiber cloth and a preform made of SiC fiber cloth. Before impregnation, the preforms were provided with an interphase coating of pyrolytic carbon (PyC) having a thickness of 1 micron for the carbon fibers, and a thickness of 0.1 microns for the SiC fibers. The deposit was obtained by chemical vapor infiltration. Table I also gives the results of tensile tests performed on a part C manufactured in similar manner, but using a preform made of SiC fiber cloth and subjected to chemical treatment for the particular purpose of eliminating the silica present at the surface of the fibers, as described in U.S. Pat. No. 5,071,679. After that treatment, a 0.1 micron thick pyrolytic carbon interphase was made by chemical vapor infiltration.
By way of comparison, Table I also shows the results of identical tensile tests performed on parts A', B', and C' made using the same preforms as the parts A, B, and C, using the same respective interphases, but consolidated by chemical vapor infiltration (using a gas) as in the prior art.
In Table I, σ T , ε and E respectively designate traction strength, strain, and Young's modulus. The relative density (d) of the parts is also given.
TABLE I__________________________________________________________________________Part A B C A' B' C'__________________________________________________________________________Preform C cloth SiC cloth SiC cloth C cloth SiC cloth SiC clothPyC interphase 1 μm 0.1 μm 0.1 μm 1 μm 0.1 μm 0.1 μmConsolidation liquid liquid liquid gas gas gasσ.sub.T (MPa) 440 210 300 480 180 280ε (%) 1 0.37 0.69 0.95 0.21 0.60E (GPa) 67 140 190 83 200 200d (g/cm.sup.3) 1.9 2.3 2.3 2.1 2.5 2.5__________________________________________________________________________
From Table I, it can be seen that the parts obtained by the method of the invention have mechanical performance of the same order as parts obtained by using a gas to consolidate the preform. The method of the invention is thus particularly advantageous since using a liquid to consolidate the preform makes it possible to achieve a cost price saving that has been calculated to be at least 30% because of the manufacturing time saved and because of the better utilization of the infiltration furnaces. It may also be observed that the method of the invention makes it possible to obtain parts of lower density than those in which the preform is consolidated by means of a gas.
EXAMPLE 2A
In this example, impregnation is performed on the fiber fabric used for making the preform, prior to shaping thereof.
Cloth made of carbon fibers and in the form of a roll, for example, is subjected to prior treatment to form a carbon interphase coating on the fibers. The coating is formed, e.g. by chemical vapor infiltration, so as to have relatively little thickness, e.g. about 0.1 micron, so as to avoid stiffening the cloth.
The cloth provided with its interphase coating is impregnated by being passed continuously through a bath and then dried in a tunnel at 80° C. during a transit time of 5 minutes. The impregnation composition is identical to that used in Example 1.
Dry plies of impregnated cloth are cut out and shaped in a hot press to obtain the desired preform. The temperature of the preform is raised uniformly to 80° C. and then with the plates of the press under pressure to avoid possible deformation of the preform, its temperature is raised to 120° C. over a period of 15 minutes and is then kept at this temperature for about 1 hour and a half.
After cooling in the press, the preform is removed for the purposes of pyrolysis and subsequent densification by SiC vapor infiltration as in Example 1.
EXAMPLE 2B
The procedure is the same as in Example 2A, but using a different impregnation composition constituted by 80 pbw of PCS, 80 pbw of hexane, 20 pbw of TMPTMA, and 0.6 pbw of dicumyl peroxide.
EXAMPLE 2C
The procedure is the same as in Example 2B, but using a different impregnation composition constituted by 40 pbw of PCS, 60 pbw of hexane, 60 pbw of TMPTMA, and 1.2 pbw of dicumyl peroxide.
Table II gives the results of tensile tests performed on parts D, E, and F obtained by the methods of Examples 2A, 2B, and 2C. By way of comparison, the results are shown as obtained on a part D' manufactured using a preform identical to that of part D, using the same carbon interphase, but consolidated by chemical vapor infiltration (i.e. by means of a gas), as in the prior art.
In Table II, ILSS designates interlaminar shear strength (i.e. resistance to shear parallel to the planes of the plies in the preform).
TABLE II______________________________________Part D E F D'______________________________________Preform C cloth C cloth C cloth C clothConsolidation liquid liquid liquid gasPCS/TMPTMA 60/40 80/20 40/60σ.sub.T (MPa) 330 270 270 260ε(%) 0.81 0.68 0.62 0.87E (GPa) 82 95 82 110ILSS (MPa) 25 about 21 20 about 19d (g/cm.sup.3). 1.82 1.87 1.73 2______________________________________
Table II shows that parts obtained by the method of the invention are lower in density than parts obtained by the prior art method, and that their performance is comparable, with the performance of the part D being substantially better than that of the parts E and F, moreover with a lower density.
EXAMPLE 3A
The procedure is the same as in Example 2A, but the carbon fiber cloth is replaced by an SiC fiber cloth.
EXAMPLE 3B
The procedure is the same as in Example 3A, but using a different impregnation composition constituted by 50 pbw of PCS, 75 pbw of TCE, 50 pbw of TMPTMA, and 1 pbw of dicumyl peroxide.
EXAMPLE 3C
The procedure is the same as in Example 3A but using a different impregnation composition, constituted by 40 pbw of PCS, 60 pbw of TCE, 60 pbw of TMPTMA, and 1.2 pbw of dicumyl peroxide.
Table III gives the results of tensile tests performed on parts G, H, and I obtained using the methods of Examples 3A, 3B, and 3C. By way of comparison, the results obtained on above-mentioned part B' are recalled.
TABLE III______________________________________Part G H I B'______________________________________Preform SiC cloth SiC cloth SiC cloth SiC clothConsolidation liquid liquid liquid gasPCS/TMPTMA 60/40 50/50 40/60σ.sub.T (MPa) 210 200 220 180ε(%) 0.37 0.38 0.53 0.21E (GPa) 140 120 110 200ILSS (MPa) 39 20 13 30d (g/cm.sup.3). 2.4 2.3 2.1 2.5______________________________________
Table III also shows that the method of the invention makes it possible to obtain parts that give comparable results to parts obtained by the prior art gas consolidation method, and in addition the parts have lower density. | A fiber preform is initially consolidated by being impregnated with a thermosetting impregnation composition that contains a ceramic precursor, and by heat treatment at the end of which the precursor has been transformed into ceramic, without passing through a meltable phase. The consolidated preform is then densified. The impregnation composition is constituted by a mixture of a thermosetting monomer and a ceramic precursor polymer, and the monomer is cross-linked during the heat treatment so as to achieve "in situ" cross-linking of the polymer mixture prior to transforming the precursor into ceramic. | 2 |
CROSS REFERENCES TO RELATED APPLICATIONS
The present application is a continuation application of U.S. Non-Provisional application Ser. No. 12/420,693 filed on Apr. 8, 2009, which, in turn, claims priority from and is a continuation application of U.S. Non-Provisional application Ser. No. 10/669,523 filed on Sep. 23, 2003, the entire contents of both of which are herein incorporated by reference for all purposes.
BACKGROUND OF THE INVENTION
The present invention relates generally to database systems and more particularly to query optimization systems and methods for use in multi-tenant database systems, wherein a centralized computer or set of computing devices serve and store applications and data for use by multiple tenants.
Multi-tenant database systems allow for users to access applications and/or data from a network source that, to the user, appears to be centralized (but might be distributed for backup, redundancy and/or performance reasons). An example of a multi-tenant system is a computing system that is accessible to multiple independent parties to provide those parties with application execution and/or data storage. Where there is an appearance of centralization, and network access, each subscribing party (e.g., a “tenant”) can access the system to perform application functions, including manipulating that tenant's data.
With a multi-tenant system, the tenants have the advantage that they need not install software, maintain backups, move data to laptops to provide portability, etc. Rather, each tenant user need only be able to access the multi-tenant system to operate the applications and access that tenant's data. One such system usable for customer relationship management is the multi-tenant system accessible to salesforce.com subscribers. With such systems, a user need only have access to a user system with network connectivity, such as a desktop computer with Internet access and a browser or other HTTP client, or other suitable Internet client.
In database systems, to access, retrieve and process stored data, a query is generated, automatically or manually, in accordance with the application program interface protocol for the database. In the case of a relational database, the standard protocol is the structured query language (SQL). SQL statements are used both for interactive queries for data from the database and for gathering data and statistics. The efficiency of the query method underlying the actual query is dependent in part on the size and complexity of the data structure scheme of the database and in part on the query logic used.
Previous database query methods have been inefficient for multi-tenant databases because such methods do not understand, and fail to account for, the unique characteristics of each tenant's data. For example, while one tenant's data may include numerous short records having only one or two indexable fields, another tenant's data may include fewer, longer records having numerous indexable fields.
In addition to these structural (schema) differences, the distribution of data among different tenants may be quite different, even when their schemas are similar. Modern relational databases rely on statistics-based query optimizers that make decisions about the best manner to answer a query given accurate table-level and column-level statistics that are gathered periodically. Importantly, however, because existing relational databases are not multi-tenant aware, these statistics cut across all tenants in the database. That is, the statistics that are gathered are not specific to any one tenant, but are in fact an aggregate or average of all tenants. This approach can lead to incorrect assumptions and query plans about any one tenant.
As a specific example, Oracle provides a query optimizer that can be used on an Oracle database. This query optimizer works generally as follows: for each table, column, or index, aggregate statistics are gathered (typically periodically or on demand by a database administrator (“DBA”)). The gathered statistics typically include the total number of rows, average size of rows, total number of distinct values in a column or index (an index can span multiple columns), histograms of column values (which place a range of values into buckets), etc. The optimizer then uses these statistics to decide among a possible set of data access paths.
In general, one goal of a query optimizer is to minimize the amount of data that must be read from disk (e.g., because disk access may be a slow operation). The optimizer therefore typically chooses tables or columns that are most “selective”—that is, will yield the fewest rows when the query condition is evaluated. For instance, if a single query filters on two columns of a single table, and both columns are indexed, then the optimizer will use the index that has the highest number of distinct values because statistically for any given filter value a smaller number of rows are expected to be returned. If the optimizer knows that a certain column has a very high cardinality (number of distinct values) then the optimizer will choose to use an index on that column versus a similar index on a lower cardinality column. The optimizer assumes relatively even distribution of data and therefore reaches the conclusion that the high-cardinality column is likely to yield a smaller number of satisfying-rows for a given equality filter.
Now consider in a multi-tenant system a physical column (shared by many tenants) that has a large number of distinct values for most tenants, but a small number of distinct values for a specific tenant. For this latter tenant the query optimizer will use this overall-high-cardinality column in error—because the optimizer is unaware that for this specific tenant the column is not selective.
In the case of table joins, the optimizer's decisions may be even more important—deciding which table to retrieve first can have a profound impact on overall query performance. Here again, by using system-wide aggregate statistics the optimizer might choose a query plan that is incorrect or inefficient for a single tenant that does not conform to the “normal” average of the entire database as determined from the gathered statistics.
Accordingly, it is desirable to provide systems and methods for optimizing database queries, and for dynamically tuning a query optimizer, in a multi-tenant database system which overcome the above and other problems.
BRIEF SUMMARY OF THE INVENTION
The present invention provides methods and systems for optimizing database queries in a multi-tenant database system. In certain aspects, for example, the present invention provides methods for dynamically tuning a query optimizer based on particular data characteristics of the tenant whose data is being searched and the particular query being executed.
The systems and methods of the present invention advantageously harness greater semantic knowledge about the use of data tables by the underlying relational database. By tracking tenant-level statistics on top of the typical system-gathered statistics (e.g., Oracle-gathered statistics), the present invention is advantageously able to optimize queries and/or make recommendations to the underlying query optimizer to improve its knowledge of the data, and therefore increase system performance, particularly for individual tenants.
According to the present invention, a multi-tenant database stores data from multiple tenants. While the overall database structure or schema is fixed, each tenant may have a tenant-specific virtual schema that describes the logical structure of that tenant's data. In certain aspects, each tenant's virtual schema includes a variety of customizable fields, some or all of which may be designated as indexable.
According to an aspect of the present invention, a method is provided for optimizing a query in a multi-tenant database having one or more data tables, each table having one or more logical columns defining data categories and one or more logical rows associated with one or more tenants, wherein a plurality of tenants have data stored in the data tables. The method typically includes generating tenant-level statistics for each of said plurality of tenants for each of the data tables, receiving a SQL query, and optimizing the SQL query based on the tenant-level statistics. In certain aspects, the method also includes generating user-level statistics for each user of each tenant and optimizing the SQL query based on the user-level statistics.
According to another aspect of the present invention, a multi-tenant database system is provided. The multi-tenant database system typically includes a database having one or more data tables, each table having one or more columns defining data categories and one or more rows associated with one or more tenants, wherein a plurality of tenants have data stored in the data tables. The database system also typically includes a statistics generating module configured to generate tenant-level statistics for each tenant for each of the data tables, and a query optimization module, configured to optimize a database query based on the tenant-level statistics. In certain aspects, the statistics generation engine is configured to generate user-level statistics for each user of each tenant, and the query optimization module is configured to optimize a database query based on the user-level statistics.
Reference to the remaining portions of the specification, including the drawings and claims, will realize other features and advantages of the present invention. Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with respect to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an environment wherein a multi-tenant database system (MTS) might be used according to one embodiment.
FIG. 2 illustrates elements of an MTS and interconnections therein in more detail according to one embodiment.
FIG. 3 illustrates an example of a data model for sharing.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates an environment wherein a multi-tenant database system might be used. As illustrated in FIG. 1 (and in more detail in FIG. 2 ) any user systems 12 might interact via a network 14 with a multi-tenant database system (MTS) 16 . The users of those user systems 12 might be users in differing capacities and the capacity of a particular user system 12 might be entirely determined by the current user. For example, where a salesperson is using a particular user system 12 to interact with MTS 16 , that user system has the capacities allotted to that salesperson. However, while an administrator is using that user system to interact with MTS 16 , it has the capacities allotted to that administrator.
Network 14 can be a LAN (local area network), WAN (wide area network), wireless network, point-to-point network, star network, token ring network, hub network, or other configuration. As the most common type of network in current use is a TCP/IP (Transfer Control Protocol and Internet Protocol) network such as the global internetwork of networks often referred to as the “Internet” with a capital “I,” that will be used in many of the examples herein, but it should be understood that the networks that the present invention might use are not so limited, although TCP/IP is the currently preferred protocol.
User systems 12 might communicate with MTS 16 using TCP/IP and, at a higher network level, use other common Internet protocols to communicate, such as HTTP, FTP, AFS, WAP, etc. As an example, where HTTP is used, user system 12 might include an HTTP client commonly referred to as a “browser” for sending and receiving HTTP messages from an HTTP server at MTS 16 . Such HTTP server might be implemented as the sole network interface between MTS 16 and network 14 , but other techniques might be used as well or instead. In some implementations, the interface between MTS 16 and network 14 includes load sharing functionality, such as round-robin HTTP request distributors to balance loads and distribute incoming HTTP requests evenly over a plurality of servers. Preferably, each of the plurality of servers has access to the MTS's data, at least as for the users that are accessing a server.
In preferred aspects, the system shown in FIG. 1 implements a web-based customer relationship management (CRM) system. For example, in one aspect, MTS 16 can include application servers configured to implement and execute CRM software applications as well as provide related data, code, forms, web pages and other information to and from user systems 12 and to store to, and retrieve from, a database system related data, objects and web page content. With a multi-tenant system, tenant data is preferably arranged so that data of one tenant is kept separate from that of other tenants so that that one tenant does not have access to another tenant's data, unless such data is expressly shared.
One arrangement for elements of MTS 16 is shown in FIG. 1 , including a network interface 20 , storage 22 for tenant data, storage 24 for system data accessible to MTS 16 and possibly multiple tenants, program code 26 for implementing various functions of MTS 16 , and a process space 28 for executing MTS system processes and tenant-specific processes, such as running applications as part of an application service.
Several elements in the system shown in FIG. 1 include conventional, well-known elements that need not be explained in detail here. For example, each user system 12 could include a desktop personal computer, workstation, laptop, PDA, cell phone, or any WAP-enabled device or any other computing device capable of interfacing directly or indirectly to the Internet or other network connection. User system 12 typically runs an HTTP client, e.g., a browsing program, such as Microsoft's Internet Explorer™ browser, Netscape's Navigator™ browser, Opera's browser, or a WAP-enabled browser in the case of a cell phone, PDA or other wireless device, or the like, allowing a user (e.g., subscriber of a CRM system) of user system 12 to access, process and view information and pages available to it from MTS 16 over network 14 . Each user system 12 also typically includes one or more user interface devices, such as a keyboard, a mouse, touch screen, pen or the like, for interacting with a graphical user interface (GUI) provided by the browser on a display (e.g., monitor screen, LCD display, etc.) in conjunction with pages, forms and other information provided by MTS 16 or other systems or servers. As discussed above, the present invention is suitable for use with the Internet, which refers to a specific global internetwork of networks. However, it should be understood that other networks can be used instead of the Internet, such as an intranet, an extranet, a virtual private network (VPN), a non-TCP/IP based network, any LAN or WAN or the like.
According to one embodiment, each user system 12 and all of its components are operator configurable using applications, such as a browser, including computer code run using a central processing unit such as an Intel Pentium processor or the like. Similarly, MTS 16 (and additional instances of MTS's, where more than one is present) and all of their components might be operator configurable using application(s) including computer code run using a central processing unit such as an Intel Pentium processor or the like, or multiple processor units. Computer code for operating and configuring MTS 16 to intercommunicate and to process web pages and other data and media content as described herein is preferably downloaded and stored on a hard disk, but the entire program code, or portions thereof, may also be stored in any other volatile or non-volatile memory medium or device as is well known, such as a ROM or RAM, or provided on any media capable of storing program code, such as a compact disk (CD) medium, digital versatile disk (DVD) medium, a floppy disk, and the like. Additionally, the entire program code, or portions thereof, may be transmitted and downloaded from a software source, e.g., over the Internet, or from another server, as is well known, or transmitted over any other conventional network connection as is well known (e.g., extranet, VPN, LAN, etc.) using any communication medium and protocols (e.g., TCP/IP, HTTP, HTTPS, Ethernet, etc.) as are well known. It will also be appreciated that computer code for implementing aspects of the present invention can be implemented in any programming language that can be executed on a server or server system such as, for example, in C, C+, HTML, Java, JavaScript, or any other scripting language, such as VBScript.
According to one embodiment, each MTS 16 is configured to provide web pages, forms, data and media content to user systems 12 to support the access by user systems 12 as tenants of MTS 16 . As such, MTS 16 provides security mechanisms to keep each tenant's data separate unless the data is shared. If more than one MTS is used, they may be located in close proximity to one another (e.g., in a server farm located in a single building or campus), or they may be distributed at locations remote from one another (e.g., one or more servers located in city A and one or more servers located in city B). As used herein, MTS's could include one or more logically and/or physically connected servers distributed locally or across one or more geographic locations. Additionally, the term “server” is meant to include a computer system, including processing hardware and process space(s), and an associated storage system and database application as is well known in the art. It should also be understood that “server system” and “server” are often used interchangeably herein. Similarly, the databases described herein can be implemented as single databases, a distributed database, a collection of distributed databases, a database with redundant online or offline backups or other redundancies, etc., and might include a distributed database or storage network and associated processing intelligence.
FIG. 2 illustrates elements of MTS 16 and various interconnections in more detail. In this example, the network interface is implemented as one or more HTTP application servers 100 . Also shown is system process space 102 including individual tenant process spaces 104 , a system database 106 , tenant database(s) 108 and a tenant management process space 110 . Tenant database 108 might be divided into individual tenant storage areas 112 , which can be either a physical arrangement or a logical arrangement. Within each tenant storage area 112 , user storage 114 might be allocated for each user.
It should also be understood that each application server 100 may be communicably coupled to database systems, e.g., system database 106 and tenant database(s) 108 , via a different network connection. For example, one server 100 1 might be coupled via the Internet 14 , another server 100 N-1 might be coupled via a direct network link, and another server 100 N might be coupled by yet a different network connection. Transfer Control Protocol and Internet Protocol (TCP/IP) are preferred protocols for communicating between servers 100 and the database system, however, it will be apparent to one skilled in the art that other transport protocols may be used to optimize the system depending on the network interconnect used.
In preferred aspects, each application server 100 is configured to handle requests for any user/organization. Because it is desirable to be able to add and remove application servers from the server pool at any time for any reason, there is preferably no server affinity for a user and/or organization to a specific application server 100 . In one embodiment, therefore, an interface system (not shown) implementing a load balancing function (e.g., an F5 Big-IP load balancer) is communicably coupled between the servers 100 and the user systems 12 to distribute requests to the servers 100 . In one aspect, the load balancer uses a least connections algorithm to route user requests to the servers 100 . Other examples of load balancing algorithms, such as are round robin and observed response time, also can be used. For example, in certain aspects, three consecutive requests from the same user could hit three different servers, and three requests from different users could hit the same server. In this manner, MTS 16 is multi-tenant, wherein the MTS 16 handles storage of different objects and data across disparate users and organizations.
As an example of storage, one tenant might be a company that employs a sales force where each salesperson uses MTS 16 to manage their sales process. Thus, a user might maintain contact data, leads data, customer follow-up data, performance data, goals and progress data, all applicable to that user's personal sales process (e.g., in tenant database 108 ). In the preferred MTS arrangement, since all of this data and the applications to access, view, modify, report, transmit, calculate, etc., can be maintained and accessed by a user system having nothing more than network access, the user can manage his or her sales efforts and cycles from any of many different user systems. For example, if a salesperson is paying a visit to a customer and the customer has Internet access in their lobby, the salesperson can obtain critical updates as to that customer while waiting for the customer to arrive in the lobby.
While each user's sales data might be separate from other users' sales data regardless of the employers of each user, some data might be organization-wide data shared or accessible by a plurality or all of the sales force for a given organization that is a tenant. Thus, there might be some data structures managed by MTS 16 that are allocated at the tenant level while other data structures are managed at the user level. Because an MTS might support multiple tenants including possible competitors, the MTS should have security protocols that keep data, applications and application use separate. Also, because many tenants will opt for access to an MTS rather than maintain their own system, redundancy, up-time and backup are more critical functions and need to be implemented in the MTS.
In addition to user-specific data and tenant-specific data, MTS 16 might also maintain system level data usable by multiple tenants. Such system level data might include industry reports, news, postings, and the like that are sharable among tenants.
In certain aspects, client systems 12 communicate with application servers 100 to request and update system-level and tenant-level data from MTS 16 that may require one or more queries to database system 106 and/or database system 108 . MTS 16 generates automatically one or more SQL statements (the SQL query) designed to access the desired information.
Each database can generally be viewed as a set of logical tables containing data fitted into predefined categories. Each table generally contains one or more data categories logically arranged in physical columns. Each row of a table contains an instance of data for each category defined by the columns. For example, a CRM database may include a table that describes a customer with columns for basic contact information such as name, address, phone number, fax number, etc. Another table might describe a purchase order, including columns for information such as customer, product, sale price, date, etc.
Now, consider in a multi-tenant system a physical column (shared by many tenants) that has a large number of distinct values for most tenants, but a small number of distinct values for a specific tenant. For this latter tenant, a typical database optimizer will choose to use this overall-high-cardinality column in error because the optimizer is unaware that for this specific tenant the column is not selective.
In the case of table joins the optimizer's decisions may be even more important—deciding which table to retrieve first can have a profound impact on overall query performance. Here again, by using system-wide aggregate statistics the optimizer might choose a query plan that is incorrect or inefficient for a single tenant that does not conform to the “normal” average of the entire database.
As a specific example of the importance of table joins, consider the sharing feature in the salesforce.com service. The sharing feature allows a specific list of users to have access to privileged data, such as specific accounts or opportunities. In one aspect, a Many-to-Many (MTM) physical table serves as the storage for this sharing information. The MTM table specifies that a user has access to a particular entity (e.g., account or opportunity) row. When displaying a list of all rows that the current user can see (possibly with a filter on the entity rows, such as the name of the account or the dollar amount of the opportunity) the query optimizer must choose between accessing this MTM table from the user or the entity side of the relationship. If the entity filter is highly selective (for instance, a particular account name such as “XYZ Corp”) it will generally make more sense to begin the query access path from this side. If, however, the entity is not filtered selectively, but the current user has access to a small amount of data, then the query optimizer should access rows in the MTM table through the user side of this relationship.
However, in the above example in a multi-tenant database system the optimizer's native statistics may be insufficient to make this determination because the native statistics will aggregate across too many tenants and will not have context into the current tenant's data.
Note, because of the wide range of business types, industries, and sizes potentially served by multi-tenant database systems such as the salesforce.com service, the likelihood of data “skew” is greatly increased. That is, the statistical profile of the largest most complex tenants is likely to look very different from that of small or medium sized customers.
In Oracle database systems, override mechanisms are provided to affect the Oracle automatic query optimizer. The use of query “Hints” allows the SQL author the ability to choose explicitly a query plan. For instance, a human-authored SQL statement might mention the explicit order of table joins, or explicit index names to use (rather than letting the optimizer choose automatically). Another mechanism for controlling the query plan explicitly is to re-write the query using different SQL syntax. For instance, a single flat SQL statement can be re-written using a nested SELECT in the FROM clause of the outer query. Joins and semi-joins are sometimes inter-changeable. Anti joins can be written using the MINUS operator, etc. All of these are examples of ways in which a human-author, or a programmatic SQL generator, can alter the behavior of the underlying query optimizer by using higher-level knowledge to change the plan.
In certain aspects, the present invention configures or tunes a query optimizer, such as the Oracle query optimizer, by supplying appropriate “hints.” For example, when SQL is generated programmatically by the MTS, the tenant-level statistics are consulted and a dynamic decision is made as to the syntax of the query. The tenant-level statistics preferably mirror the underlying relational database statistics in many ways (for example, in one aspect they track the total number of distinct values for indexed columns) but the statistics are kept on a per-tenant basis (e.g., in tables in tenant database storage areas 112 ). Similarly for important application functionality, such as the sharing feature, the MTS tracks the approximate number of rows to which each user has access and stores such statistics (e.g., tables stored in user storage areas 114 of database 108 ). Then, when a filtered sharing query arrives, the dynamically generated SQL includes the appropriate hints and structure to force a query plan that is optimal.
Optimizer
In one aspect, metadata information about users and tenants/organizations and the data contained in entity rows for that tenant are tracked (e.g., relevant information and metadata stored to separate user-level and tenant-level data tables) in order to make choices about query access paths, particularly for list-style queries such as reports. The areas targeted include:
1. The evaluation of a sharing model, which controls which users can see which records. The optimizer preferably distinguishes between users that can see many rows in an organization (e.g., bosses) versus users who can see very few rows (e.g., lower level employees). 2. The choice of which filters are the most selective for fields that contain enumerated lists of values (e.g., list of status values for an account, list of industries, list of states, etc.).
Sharing Model
For each user in the system an approximate count of the number of rows (for each entity type that has a sharing model) that the user can see is tracked. This number of rows (as a percentage of the total number of entity rows for that organization) is used as a decision point in choosing between two different query paths. It has been determined empirically that users who can see most of the entity rows (e.g., bosses) benefit from a certain query structure, whereas users who can see a small percentage of the entity rows (e.g., lower level employees) benefit from a different query structure. Current systems are not able to choose between these paths without having an entirely different SQL provided via a programmatic decision. In preferred aspects, an optimization engine reads data from multi-tenant data tables and stores metadata (e.g., number of rows accessible per tenant or per user, or other metadata) to tenant-level tables or user-level tables in database 108 . For example, a tenant-level metadata table might be stored to a tenant storage area 112 and a user-level table might be stored to a user storage area 114 . For example, in one aspect, the optimization engine includes a statistics generation engine that process multi-tenant tables and produces tenant-level and user-level statistics tables. The optimization engine and statistics generation engine might execute in process space 110 or other process space. The optimization engine retrieves and processes the appropriate tables when optimizing SQL queries. In other aspects, flags or tags are implemented in the multi-tenant database tables to distinguish users and tenants.
In order to keep the statistics up to date it is important to track the percentage of rows that each and every user can see. In one aspect, there are three ways in which a user might gain access to data in a private security model:
(1) Rows owned by the user or users below him in the role hierarchy; (2) Rows that are shared via sharing rules to a group to which this user belongs; and (3) Rows that are shared via manual/team sharing to this user (possibly via a group).
In a preferred aspect, statistics and metadata are tracked for user and organization quotas. In some aspects, such information is tracked periodically (e.g., on a scheduled basis—during off-peak hours, amortizing the work over multiple days), wherein the number of visible rows for each user is calculated exactly or approximately, or before every Nth query (e.g., every 10 th query) by a user, that user's visibility is calculated explicitly and then that statistic is used until it is again calculated (here it is assumed that users do not change very often from one strategy to another). In yet a further aspect, whenever an unconstrained query is run, the number of visible rows is remembered and that number is used until the user runs the next unconstrained query.
In one aspect, the total number of rows for each entity type for each organization is tracked (this is useful for any of the strategies above). Also, the total number of rows owned by each user in a metadata table is tracked.
If it is assumed that (1) and (2) are the most important reasons for why a user has access to entity records (this might be known empirically from how organizations use the system) then the information needed to calculate the number of rows a user can see, approximately, is known. Namely, the role hierarchy metadata tables can be used in conjunction with the metadata table to determine the number of records owned by the user or his subordinates. The sharing rule metadata can also be used along with the group definition metadata to calculate the total number of rows visible via sharing rules. While these two sets may overlap, for the purpose of the heuristic decision between “boss” and “lower level employee,” the sum of these two values is sufficiently close to the true value.
In one aspect, the use of metadata tables only (which are generally much smaller than the actual entity tables which might have millions of rows) ensures that the calculation of visible rows will itself not require much time. In one aspect, this decision is cached in a user-information data structure kept by the running application servers 100 , e.g., with a timeout value. In this manner, even though the calculation itself may be relatively lightweight, it is only performed periodically while a user is logged in.
To focus on how the “boss” vs “lower level employee” decision should drive an appropriate query plan, consider a query of the form: “Show me all accounts that I can see” in a private account sharing model. An example of a data model for sharing appears in FIG. 3 (middle table is sharing table, final table is the user/group “blowout” table which describes which users are contained in a group, or above a user in the role hierarchy (UG=User or Group)). According to one aspect, for a “lower level employee” user it is typically most advantageous to join these tables starting from the right, filtering on users Id to form a temporary result of the rows that can be seen. Because the user can not see many rows, this will yield a relatively selective path. An example query follows:
select a.name “ACCOUNT.NAME”,
from sales.account a,
(select distinct s.account_id
from core.ug_blowout b, sales.acc_share s
where s.organization_id = ?
and b.organization_id = ?
and b.users_id = ?
and s.ug_id = b.ug_id
and s.acc_access_level > 0) t,
core.users u
where (t.account_id = a.account_id)
and (u.users_id = a.owner)
and (a.deleted = ‘0’)
and (a.organization_id = ?)
and (u.organization_id = ?))
Conversely for a “boss” user who can see most of the entity records in the organization, it is typically most advantageous to begin the query from the left and use a nested loop query plan onto the sharing table (acc_share), an example of which follows:
select
a.name “ACCOUNT.NAME”,
from
sales.account a, core.users u
where (u.users_id = a.owner)
and (a.deleted = ‘0’)
and (a.organization_id = ?)
and (exists (select 1
from core.ug_blowout b,
sales.acc_share s
where s.organization_id = ?
and b.organization_id = ?
and b.users_id = ?
and s.ug_id = b.ug_id
and s.acc_access_level > 0
and s.account_id = a.account_id))
and (u.organization_id = ?)
Note that this query in general runs in relatively constant (reasonable) time for all users in an organization. It may not be particularly fast since it must look at all top-level entity records, but it is suitable for a boss who can in fact see most records. The first “lower level employee” query runs much faster for users who in fact can not see many records, but it may run much slower for bosses who can see all records. This, again, is why it is desirable to have an accurate decision between the two paths.
Filter Choice
A typical end user report execution includes a set of displayed columns from multiple tables along with a set of filter conditions. A typical report might join between 3 and 7 (or more) main tables with filtering possibly occurring on one or more of these tables. In addition, certain filters, such as the sharing filter discussed above (which can take the form of an additional join or a nested sub-query), should be applied to assure that the end user only sees data to which he has been given access.
Information about enumerated “picklist” fields (those fields that are known to contain a small list of possible values) are tracked in one aspect. Examples of these fields include the list of priority values for a task and the list of industries for an account. These fields are often used as filters for executive reporting and data rollup reports. In addition to the values themselves, the approximate number of times each value appears in the actual entity table for that organization (tenant) is tracked in the metadata. When a user provides a filter value such that the value appears infrequently for that organization, the overall query is preferably driven from that table and possibly from an index on that column, if such as index exists.
In one aspect, when a user runs a report with N filters, each filter is evaluated for expected selectiveness. If, for example, the user filters on “California” and “Florida” from a list of states and it is known that these values represent, respectively, 5 and 2 percent of the overall rows, then it is assumed that the filter has a 7% selectivity. Similarly if a boolean field has 95% true values, then filtering on false appears attractive as a filter, whereas filtering on Male from a random list of people would not be very selective, since 50% reduction would not make a good filter condition.
The selectivity of the sharing condition is also considered in one aspect. For a user with very low (perhaps 2%) visibility, the sharing filter might prove to be the best starting point and therefore the optimizer is instructed to begin with the filter, rather than one of the main entity tables such as, e.g., Account or Contact tables.
The cost-based optimizer, in one aspect, incorporates other filter types, in addition to semantics knowledge about the application. For example, if an organization has imported all opportunities for the last 3 years, and a user report filters on “all opportunities that closed in the last week” then this is likely to represent a selective filter. The presence of custom field indexes (e.g., a certain set of columns that administrators can choose to place into a B-tree indexed custom field columns into these heuristic decisions) are also factored in one aspect.
In one aspect, a query is only hinted if it is assumed that a particular starting table will yield a selective path. All other tables would then be joined via nested loops. Note, these types of cost-based decisions are similar to the decisions that the optimizer (e.g., Oracle optimizer) itself makes when deciding how to join tables. Importantly, the system of the present invention makes tenant-level data decisions based on tenant-level statistics and user-level data decisions based on user-level statistics. The system of the present invention also takes into account application-level concepts such as sharing that are beyond the generic nature of the underlying RBDMS.
For picklist fields, the statistics tracked and stored do not need to reflect the exact number of occurrences for each value, a reasonable estimate is sufficient in one aspect. Values missing from the statistics either do not occur at all, or occur infrequently—it is assumed that they make good filters.
In one embodiment, each update or insert into an entity table passes through an application server 100 . Therefore as the data is being processed in Java counters are incremented and decremented for individual picklist values. Inserts increment a counter, while updates to a different value decrement a counter for the old value and increment a counter for the new value. Since these statistics do not need to be exact, the statistics metadata is preferably not updated with each and every database insert or update (which might affect performance). Rather, in one aspect, an in-memory cache server (which already contains the metadata for valid picklist values) is augmented with the counters for these values, with the ability to update the database values periodically to persist the changes. An example of such a cache server can be found in U.S. patent application Ser. No. 10/418,961, filed Apr. 17, 2003, titled “Java Object Cache Server for Databases”, the contents of which are hereby incorporated by reference in its entirety.
For row deletion, the data preferably does not pass through the application server 100 . However, all main entities are preferably soft-deleted (with a modification stamp), meaning the rows are left in the database for possible un-deletion. Therefore, an asynchronous process is preferably used to update the statistics when rows are deleted and un-deleted since it is known which rows have been touched since the last running of that process.
While the invention has been described by way of example and in terms of the specific embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. | More efficient querying of a multi-tenant database using dynamic tuning of database indices. A layer of meta-data associates data items with tenants, e.g., via tags, and the meta-data is used to optimize searches by channeling processing resources during a query to only those pieces of data bearing the relevant tenant's unique tag. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Patent application Ser. No. 11/906,048 filed Sep. 28, 2007 and which is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to molded plastic siding panels which are used to cover an exterior building wall surface and, in particular, to a molded plastic siding panel which has improved locking and attachment features.
BACKGROUND OF THE INVENTION
[0003] Molded plastic siding panels used on exterior wall surfaces are well known in the prior art. These siding panels are typically made of synthetic thermoplastic polymers and are nailed to a wall support surface in horizontal rows partially overlapping each other for aesthetic purposes. The siding panels are typically installed on a wall surface starting with a bottom course and nailing several adjacent courses. Side marginal edge regions of each panel can mate with adjacent panels utilizing a male-female tongue-in-groove configuration.
[0004] Various arrangements have been proposed for interlocking a siding panel with another siding panel provided directly above it. For example, U.S. Pat. No. 6,224,701 to Bryant, et al. discloses a molded plastic panel for covering an exterior building wall. The panel has a panel body which includes a locking lip for engaging a locking tab on an adjacent panel and a flexible hinge which connects the locking lip to the panel body. The panel also has an attachment hem or nail hem adjacent to a top wall having laterally elongated, laterally spaced nail slots 31 of the same size for locating nails.
[0005] U.S. Pat. No. 6,955,019 to Donlin, et al. shows a wall covering comprising a plurality of plastic panels which are mounted on a support surface with a lower marginal edge region of one panel overlaying an upper marginal edge region of a previously mounted panel in a lower course and with a side marginal edge region of one panel overlying the side marginal edge region of the previously mounted adjacent panel in the same course. The marginal edge regions are provided with interlocks which engage and secure both the overlapping upper and lower marginal edge regions and the overlapping side marginal edge regions. For securing a panel to a support surface, the upper marginal edge region of each panel is formed with a row of elongated laterally spaced nailing apertures of the same size.
[0006] In conventional panels which have intermittent locks, the siding installers may occasionally miss a lock and due to the line of sight during the installation, it may not be detected until the installer is finished with the installation and is reviewing the work. The missed lock would then be readily apparent and the correction of this would require the installer to reset the panel.
[0007] Although U.S. Pat. No. 6,715,250 discloses a conventional siding panel which utilizes a continuous lock feature in which the panel is injection molded with a living hinge which is folded and welded to the panel to form the top lock, this panel requires additional steps to form the top lock.
[0008] Additionally, conventional siding panels are provided with nail slots having a center nail hole that substantially anchors the location of the panel with all of the other nail holes being slots of the same size in which nails are inserted and left slightly raised so they do not anchor the panel to the wall and thereby allow the panel to expand and contract with a change in temperature and still remain flat on the wall. However, these conventional panels have a problem in that the center hole must be aligned with a stud in a non-nail based sheathing installation, i.e., a sheathing not capable of adequately supporting a fastener.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to provide a molded plastic siding panel having a continuous top interlocking mechanism that will easily allow the alignment of adjacent siding panels during installation.
[0010] It is a further object of the present invention to provide a plastic siding panel having an attachment portion with nail slots provided therein which allow any slot provided on the panel to be used for the center location, such that the stud closest to the center of the panel to be the anchoring nail location.
[0011] It is still a further object of the present invention to provide a plastic siding panel having an attachment portion with nail slots provided therein which allows any nail slot provided on the panel to be used as the centermost anchoring location regardless of the cut in the panel or location of intermediate framing members.
[0012] These and other objects of the present invention are met by providing a monolithic molded plastic siding panel which is made in one molding process and comprises a continuous top interlocking mechanism which facilitates an easier installation by minimizing the chances of a non-continuous top interlocking mechanism not engaging with a bottom interlocking mechanism provided on an adjacent panel.
[0013] These and other objects of the present invention are met by providing a plastic siding panel which has a continuous top interlocking mechanism formed by a separate member which engages with the attachment portion in a snap-fit connection.
[0014] These and other objects of the present invention are also met by providing a plastic siding panel having an attachment portion containing apertures which gradually become more horizontally elongated as they are positioned away from a center portion of the attachment portion, thereby enabling any of the apertures to serve as a center anchoring position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 illustrates the top and bottom locking mechanisms of a plastic siding panel according to an embodiment of the present invention.
[0016] FIG. 2 illustrates a top interlocking mechanism of a plastic siding panel according to another embodiment of the present invention.
[0017] FIG. 3 illustrates the apertures contained in an attachment portion of a plastic siding panel according to an embodiment of the present invention.
[0018] FIG. 4 illustrates an embodiment of an attachment portion of a siding panel of the present invention where the nail slots progressively become wider as they extend from right to left.
[0019] FIG. 5 illustrates an embodiment of an attachment portion of a siding panel of the present invention where the nail slots progressively become wider as they extend from left to right.
[0020] FIG. 6 illustrates an embodiment of an attachment portion of a siding panel of the present invention where the nail slots have the same width for a portion of the right side of the siding attachment portion and then progressively become wider as they extend from right to left.
[0021] FIG. 7 illustrates an embodiment of an attachment portion of a siding panel of the present invention where the nail slots have the same width for a portion of the left side of the siding attachment portion and then progressively become wider as they extend from left to right.
[0022] FIG. 8 illustrates an embodiment of an attachment portion of a siding panel of the present invention where the nail slots have the same width at a center portion of the siding attachment portion and then progressively become wider as they extend outwardly from the siding center portion.
[0023] FIG. 9 illustrates an embodiment of an attachment portion of a siding panel of the present invention where a conventional siding top interlocking mechanism is converted into a continuous top interlocking mechanism of the present invention.
[0024] FIG. 10 is a front elevation view.
DETAILED DESCRIPTION OF THE INVENTION
[0025] FIG. 1 illustrates an embodiment of a plastic siding panel 1 according to the present invention. The plastic siding panel 1 is monolithic and is prepared by molding a thermoplastic resin selected from the group consisting of a polyolefin, a polycarbonate, polyvinyl chloride, and mixtures and copolymers thereof. Preferably, the thermoplastic resin is a polyolefin, with polypropylene being especially preferred. Conventional additives used in siding panels can be present in the siding panel of the present invention and include fillers, pigments, UV inhibitors, anti-oxidants, etc.
[0026] The thermoplastic resin can be formed into the monolithic plastic siding panel of the present invention by conventional molding processes such as injection molding, compression molding, transfer molding, extrusion molding, blow molding, etc. with injection molding being preferred. As illustrated in FIG. 1 , the monolithic molded plastic siding panel 1 of the present invention comprises a rectangular shaped body portion 2 and a strip-shaped attachment portion 3 provided immediately above and adjacent to the body portion 2 . Panel 1 has a top edge T, a bottom edge B, and front and rear surfaces F, R.
[0027] As illustrated in FIGS. 1 and 3 , an embodiment of an attachment portion 3 of the present invention is provided with a plurality of apertures 15 which sequentially become more horizontally elongated as they are position away from a center position C on the attachment portion 3 . The apertures 15 serve as nail slots for fastening the plastic siding panel 1 to a wall structure. The varying widths of the apertures 15 eliminate the need to initially fasten the panel through a center nail slot and will prevent the siding panel 1 from distorting in dramatic temperatures regardless of the width of the panel. It is only necessary that the fastener be placed at the center of the aperture or nail slot 15 . Markings can be provided on the attachment portion 3 to indicate the center of the nail slots 15 and/or the nail slots may be formed to guide the fasteners into the proper position.
[0028] A continuous top interlocking mechanism 5 is provided on an upper portion of the siding panel 1 , preferably on the attachment portion 3 immediately below the apertures 15 . The top interlocking mechanism 5 is adapted to engage with a bottom interlocking mechanism 10 provided on an adjacent panel to align the panels on the wall structure during installation. As illustrated in FIG. 1 , the top interlocking mechanism 5 comprises a plurality of spaced-apart ledge portions 6 which extend laterally from the attachment portion 3 . Each ledge portion 6 has a length L. As seen in FIGS. 1 and 10 , the length L is defined by the distance between the edges E of each ledge portion 6 . At least two whole apertures 15 are located within length L of each ledge portion 6 . The spaced-apart ledge portions 6 are separated by ledge slots S and joined by a continuous side wall portion 7 which is joined to and extends downwardly from the ledge portions 6 . Alternatively, the continuous top interlocking mechanism 5 can be provided on the attachment portion 3 above the apertures 15 without departing from the scope of the present invention.
[0029] At a lower portion of the body portion 2 , a bottom interlocking mechanism 11 is provided. The bottom interlocking mechanism 10 comprises a continuous ledge portion 11 which extends laterally along the length of the body portion 2 in a direction opposite to the ledge portions 6 and a continuous lip portion 12 which extends upwardly from the continuous ledge portion 11 . The bottom interlocking mechanism 10 is adapted to resiliently engage with the top interlocking mechanism 5 through the resilient engagement between the continuous side wall 7 and the continuous lip portion 12 . As with conventional siding panels, a longitudinally extending groove can be provided in one of the side surfaces of the body portion 2 and a longitudinally extending ridge can be provided in the opposite side surface which is adapted to engage with a longitudinally extending groove provided in an adjacent siding panel.
[0030] Another embodiment of the top interlocking mechanism 8 of the present invention is illustrated in FIG. 2 . In this embodiment, the attachment portion 3 is molded to form a first connection member 16 containing a space 17 defined by a bottom wall 18 and inwardly extending lips 19 which is adapted to receive a plug portion 21 of a second connection member 20 . The second connection member 20 is an extruded part which extends laterally continuously along the width of the attachment portion 3 and together forms the top interlocking mechanism 5 with the first connection member 16 when the plug portion 21 is engaged in the space 17 . The plug portion 21 has a bottom wall 24 which flush engages with the bottom wall 18 of the space 17 and outwardly extending lips 25 having a top surface which sealingly engages with the bottom surface of lips 19 to firmly attach the second connection member 20 to the first connection member 16 and form another embodiment of the continuous top interlocking mechanism 5 of the present invention.
[0031] FIG. 9 illustrates another embodiment of the top interlocking mechanism 9 of the present invention wherein a conventional top interlocking mechanism 30 made up of a plurality of “L-shaped” spaced-apart locking members 31 is converted to a continuous top interlocking mechanism of the present invention by inserting a continuous “U-shaped” member 32 by inserting U-shaped member 32 under the L-shaped member 31 along the entire width of the attachment portion 10 .
[0032] FIGS. 4-8 all illustrated different embodiments of the nail slots 15 provided on an attachment portion 3 of the present invention. In FIG. 4 , the nail slots 15 progressively become wider as they are provided in the leftward direction on the attachment portion 3 . FIG. 5 illustrates an embodiment of an attachment portion 3 of the present invention in which the nail slots 15 progressively become wider as they are provided in the rightward direction along the attachment portion 3 . FIG. 6 illustrates an attachment portion 3 according to an embodiment of the present invention where the nail slots 15 have a constant size at the right side of the attachment portion 3 and then become progressively wider as they are provided in the leftward direction along the attachment portion 3 . FIG. 7 illustrates another embodiment of an attachment portion 3 of the present invention where the nail slots 15 have a constant size at the left side of the attachment portion 3 and then become progressively wider as they are provided in the rightward direction along the attachment portion 3 . FIG. 8 illustrates an attachment portion 3 according to another embodiment of the present invention wherein the nail slots 15 have a constant size at a central portion of the attachment portion 3 and become progressively wider as they are provided outwardly from the central portion of the attachment portion 3 .
[0033] By providing the attachment portion 3 with nail slots 15 having a different width, it is not necessary for a center nail slot of an attachment portion to be centered on a nail stud during installation of the plastic siding as the varying widths of at least some of the nail slots 15 allow them to be used as the center nail slot and still give the siding panel the ability to compensate for thermal expansion and reduction. Additionally, the attachment portion of the present invention having nail slots of varying widths are especially suitable for use in non-nail based sheathing applications using rigid foam, gypsum, etc. where the varying widths of the nail slots allow the nails slots to be easily located over a framing member without the need for a center nail hole to be provided over a framing member, or in installations where a sheathing member is not used.
[0034] The body 2 of the siding panels of the present invention can be provided with a decorative pattern characteristic of conventional roofing and siding materials such as shake shingles, tile, brick or the like and the color of the siding panel can be evenly distributed throughout the resin, painted on the siding panel or achieved by a combination thereof. Moreover, since the monolithic plastic siding panels of the present invention are molded in one molding process step, there is no need for hinges or other attached components as is typically required with the prior art plastic siding panels.
[0035] Although the present invention has been described in connection with specific embodiments, it is not limited to the particular constructions herein disclosed and shown in the drawings and also comprises any modifications or equivalents within the scope of the appended claims. | A molded plastic sliding panel used for covering an exterior building wall surface is made up of a body portion, an attachment portion provided above and adjacent to the body portion, a top locking portion extending horizontally across an upper portion of the sliding panel and a bottom locking portion provided at the bottom of the body portion. The top locking portion is adapted to engage with the bottom locking portion on an upper adjacent siding panel. The attachment portion can contain a plurality of apertures provided therein which sequentially become more elongated as they are positioned toward a side edge of the attachment portion in order to deal with thermal expansion and contraction of the panel. | 4 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a process for producing a laminated sheet comprising an alumina fiber precursor spun out from a spinning solution containing an aluminum compound. More particularly, it relates to a process for producing a laminated sheet comprising an alumina fiber precursor having a uniform basis weight throughout. Alumina fiber sheet obtained by calcining the said laminated sheet has excellent refractory and heat insulating properties as well as high mechanical strength and chemical stability even under high temperatures and are used as a high-temperature refractory/heat insulator, high-temperature cushioning medium and such.
[0002] It is known to produce alumina fiber by first forming an alumina fiber precursor by spinning from a spinning solution, and then calcining the said precursor. This method is especially suited for producing alumina fiber whose alumina content exceeds 65% by weight, such the production that the conventional melt fiber-forming method is inapplicable. The spinning solution used in this method is principally comprising an aluminum compound and contains small amounts of various adjuvants. The adjuvants include those which become the structural elements of the finally produced alumina fiber, such as metal compounds, and those which serve for adjusting the properties of the spinning solution, such as water-soluble polymeric compounds. For example, a spinning solution prepared by adding silica sol and polyvinyl alcohol to a basic aluminum chloride solution formed by dissolving aluminum in hydrochloric acid is used.
[0003] Blowing method and spindle method utilizing centrifugal force are known for spinning out an alumina fiber precursor from a spinning solution, but usually blowing method is used. According to this blowing method, the spinning solution is supplied into a high-speed spinning air stream from a nozzle, the supplied spinning solution being drawn out in the spinning air stream, deprived of moisture and solidified to form an alumina fiber precursor.
[0004] The thus formed alumina fiber precursor is amassed to form an alumina fiber precursor sheet having a specified basis weight, i.e., a specified weight per unit area. Although the constituent alumina fiber precursor has flexibility, the precursor sheet itself is low in fiber strength and also unstable as it contains structural water and/or additives in fiber, so that usually this precursor sheet, can not be offered as a commercial product in the form as it is. Therefore, it is necessary to calcine the alumina fiber precursor sheet to form an alumina fiber sheet having high crystallinity while maintaining a stable oxide state. It is also possible to obtain an alumina fiber sheet with even higher mechanical strength by needling the precursor sheet before calcining. (See U.S. Pat. Nos. 4,752,515, 4,931,239 and 5,104,713).
[0005] As means for producing an alumina fiber precursor sheet having a specified basis weight (fiber weight per unit area or basis area weight) by amassing the alumina fiber precursor, a method is known in which the alumina fiber precursor in the spinning air stream is fallen and stacked on an accumulator until a sheet with a specified basis weight is formed. For example, the alumina fiber precursor is fallen and stacked on a rotating endless belt, and the alumina fiber precursor sheet formed by stacking the said precursor is successively tugged out from the endless belt.
[0006] A method is also known in which the alumina fiber precursor carried in the spinning air stream is fallen and stacked on an accumulator to form a thin lamina sheet which is far smaller in thickness than the sheet to be formed having a specified basis weight, and this lamina sheet, in the next step, is wound round a number of times until forming the sheet with a specified basis weight. In a typical example of this method, a spinning air stream containing the alumina fiber precursor is let impinge almost at right angles against a rotating endless belt of the type which allows easy passage of air, such as a belt made of (metal) wire mesh (net). The spinning air stream is allowed to pass through the endless belt, but the alumina fiber precursor is caught and amassed on the endless belt to form a lamina sheet. This lamina sheet of alumina fiber precursor is pulled apart from the endless belt and wound around a rotator in whatever layers until forming a sheet having a specified basis weight. Then the roll of the laminated sheet on the rotator is cut into sections, and subjected to the ensuing steps such as calcining.
[0007] According to the above method, although capture and amassing of the alumina fiber precursor from the spinning air stream is easy, the sheet forming operations are complicated as they are batch type, and further, since the length of the sheet that can be treated depends on the circumferential length of the rotator, it is impossible to obtain sheets of all required lengths.
[0008] A further problem of the said conventional method is that the formed alumina fiber precursor sheet is non-uniform in basis weight along the width thereof, the basis weight being particularly small at both end portions of the sheet. This is for the reason that when the alumina fiber precursor is fallen from the spinning air stream and stacked on an accumulator, the precursor does not stack uniformly along the whole width of the accumulator, and most remarkably the stacking at both ends in the width direction is relatively small.
[0009] That the basis weight of the alumina fiber precursor sheet is non-uniform along the width thereof, particularly small at both ends, signifies corresponding variation of the basis weight of the calcined alumina fiber sheet in its width direction. An alumina fiber sheet as a commercial product is required to be uniform in basis weight in its entirety, so that both end portions in the width direction where the basis weight is smaller than the specified value must be cut out rather overly, which results in a reduced yield of the alumina fiber sheet. Also, even if both end portions are cut out, the sheet would have to be disposed off as a substandard product if there still exists a portion where the basis weight is outside the specified range.
[0010] In recent years, attention is focused on application of alumina fiber sheets to such areas as holding means for exhaust gas cleaning systems, heat-resistant filters and the like, and in such uses, higher precision of sheet thickness than in the conventional uses is required. For example, in the internal combustion engines, as a measure for disposal of exhaust gas, a cleaning system having a honeycomb catalyst housed in a casing is provided in the exhaust gas passage. For securely holding such honeycomb catalyst in the catalyst casing, it is necessary to wind a holding mat for catalyst holding member around the honeycomb catalyst to as much a uniform thickness as possible and house this catalyst in the casing so that it will be closely secured to the inside wall of the casing by the restoring force of the holding member. Such a holding member is preferably a fiber sheet which is proof against fiber deterioration and capable of maintaining an appropriate surface pressure even under high temperatures. Japanese Patent Application Laid-Open (KOKAI) No. 7-286514, for instance, teaches that among alumina fiber sheets, the one produced by laminating alumina fiber having a composition of Al 2 O 3 :SiO 2 =70−74:30−26 (by weight) and needling the laminate is especially preferred.
[0011] As a result of the present inventors' earnest studies to solve the above problem, it has been found that by folding the thin lamina sheet of alumina fiber precursor by a predetermined width while stacking the folded sheet and continuously moving the stacking sheet in the direction orthogonal to the folding direction, the obtained alumina fiber precursor sheet has uniform basis weight along the full width thereof.
[0012] The present invention has been attained on the basis of the above finding.
SUMMARY OF THE INVENTION
[0013] An object of the present invention is to provide a process for producing an alumina fiber precursor sheet which is uniform in basis weight along the full width thereof.
[0014] To attain the above aim, in the first aspect of the present invention, there is provided a process for producing a laminated sheet comprising an alumina fiber precursor, which process comprises spinning out an alumina fiber precursor from a solution mainly comprising an aluminum compound, falling and stacking said alumina fiber precursor on the surface of an accumulator to form a thin lamina sheet of alumina fiber precursor, continuously pulling out said lamina sheet from the accumulator, transferring the resultant lamina sheet to a folding device, and folding the sheet by a predetermined width while stacking the folded sheet and continuously moving the stacking sheet in the direction orthogonal to the folding direction.
[0015] In the second aspect of the present invention, there is provided a process for producing an alumina fiber sheet which comprises calcining a laminated sheet of alumina fiber precursor obtained from a process according to the first aspect.
[0016] In the third aspect of the present invention, there is provided a holding mat for catalyst holding member, which comprises an alumina fiber sheet produced by needling and calcining a laminated sheet of alumina fiber precursor obtained from a process comprising spinning out an alumina fiber precursor from a solution mainly comprising an aluminum compound, falling and stacking said alumina fiber precursor on the surface of an accumulator to form a thin lamina sheet of alumina fiber precursor, continuously pulling out said lamina sheet from the accumulator, transferring the resultant lamina sheet to a folding device, and folding the sheet by a predetermined width while stacking the folded sheet and continuously moving the stacking sheet in the direction orthogonal to the folding direction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] [0017]FIG. 1 is a schematic flow sheet illustrating an embodiment of the present invention.
[0018] [0018]FIG. 2 is a schematic illustration of a folder system usable in carrying out the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The present invention is described in detail below.
[0020] In the present invention, preparation of the spinning solution and formation of the alumina fiber precursor can be accomplished according to the conventional methods. For example, the spinning solution can be prepared by forming a basic aluminum chloride solution by dissolving aluminum in hydrochloric acid, and adding silica sol to the solution so that the finally obtained alumina fiber will have a composition of Al 2 O 3 :SiO 2 =preferably 65˜98:35˜2, more preferably 70˜97:35˜3 (by weight). When the silicon content increases excessively, although it becomes easy to form fibers, heat resistance lowers excessively, while a too small silicon content make the fibers fragile. In order to improve spinnable properties, it is preferable to add a water-soluble organic polymer such as polyvinyl alcohol, polyethylene glycol, starch, cellulose derivatives or the like. In some cases, the solution is properly concentrated to adjust the viscosity usually to 10 to 100 poise.
[0021] Blowing method, in which the spinning solution is supplied into a high-speed spinning air stream, is preferably used for forming alumina fiber precursor from the spinning solution. The nozzles usable in the blowing method include two types: in one type, a spinning solution nozzle is provided in an air stream nozzle which generates a spinning air stream; in the other type, a spinning solution nozzle is provided so as to supply the spinning solution externally to the spinning air stream. Both types can be used in the present invention. In case where spinning is carried out according to the said blowing method, preferably an endless belt made of metal gauze is set substantially at right angles against the spinning air stream, and the spinning air stream containing the formed alumina fiber precursor is let impinge against the rotating belt. The alumina fiber precursor formed by the said spinning is usually about several micrometers (μm) in diameter and several ten to several hundred mm in length.
[0022] The thin lamina sheet of alumina fiber precursor formed on the accumulator is successively pulled out from the accumulator and transferred to a folder by which the sheet is folded to a predetermined width and amassed, and the amassed sheet is continuously moved in the direction orthogonal to the folding direction. In other words, the lamina sheet is successively pulled apart from the accumulator, folded and stacked in the advancing direction of the sheet, and continuously moved transversely to the folding direction. Therefore, the folded sheet width becomes equal to the width of the laminated sheet to be formed. Thereby both end portions in the width direction of the lamina sheet are dispersed in the formed laminated sheet, so that the basis weight of the laminated sheet becomes uniform throughout the sheet.
[0023] The basis weight of the lamina sheet should at least be enough to form a thinnest allowable sheet; it is usually 10 to 200 g/m 2 , preferably 30 to 100 g/m 2 . This thin lamina sheet is not necessarily uniform in both of its crosswise and longitudinal directions, so that the laminated sheet is formed by laminating the lamina sheet in at least 5 layers, preferably 8 or more layers, more preferably 10 to 80 layers. By this lamination, local non-uniformity of the lamina sheet is countervailed, so that it is possible to obtain a laminated sheet having a uniform basis weight throughout. The number of laminations is not specifically limited, but it is to be noted that a too large thickness of the sheet may make it unable to obtain preferred improvement of peel strength in the thickness direction by needling normally conducted in a later step, or may cause a reduction of sheet productivity.
[0024] For forming the laminated sheet, the lamina sheet is delivered out continuously from the accumulator and transferred to a folder whereby the sheet is folded to a predetermined width, stacked and continuously moved in the direction orthogonal to the folding direction. For example, in the accumulator, alumina fiber precursor is stacked on a metal gauze-like rotating endless belt to form a thin lamina sheet, and this sheet is separated from the endless belt and forwarded to the folder. In this folder, the sheet is folded to a predetermined width and piled up on an endless belt rotating in the direction substantially orthogonal to the folding direction. The number of laminations of the laminated sheet depends on the moving speed of the endless belt. Slow speed increases the number of laminations, while fast speed decreases the number of laminations.
[0025] [0025]FIG. 1 is a schematic flow sheet illustrating an embodiment of the present invention. In this embodiment, there is used a folding system 3 comprising an endless belt 1 for carrying the lamina sheet 2 , another endless belt 5 for carrying the laminated sheet, said endless belt 5 being disposed at a position lower than the endless belt 1 and in the direction transverse thereto, and a folding means by which the lamina sheet hanging from the rear end of the endless belt 1 is folded and stacked on the endless belt 5 . In this folding system 3 , the folding means is arranged movable laterally, and the width of the laminated sheet is decided by the range of travel of the folding means. Use of such folding system makes it possible to continuously produce a laminated sheet 4 of any optional width from the continuously transferred thin lamina sheet.
[0026] The folding system usable in the present invention is not limited to the structure illustrated in FIG. 1; it is possible to use a vertical folding system such as illustrated in FIG. 2.
[0027] The thus produced laminated sheet of alumina fiber precursor is then calcined by a conventional method and thereby made into an alumina fiber sheet. Calcining is carried out usually at a temperature not lower than 500° C., preferably 1,000 to 1,300° C. When the laminated sheet is subjected to needling before calcining, it is possible to obtain an alumina fiber sheet with high mechanical strength in which the alumina fibers are also oriented in the thickness direction. Needling is conducted usually at a rate of 1 to 50 stitches/cm 2 . Generally, the higher the needling rate is, the higher become the bulk density and peel strength of the obtained alumina fiber sheet.
[0028] According to the present invention, it is possible to produce a laminated sheet of alumina fiber precursor having a uniform basis weight throughout. By calcining this laminated sheet by a conventional method after needling, if necessary, there can be obtained an alumina fiber sheet having a uniform basis weight throughout. Further, the present invention enables continuous production of alumina fiber sheet of any optional length with ease and can remarkably improve production efficiency over the conventional methods.
EXAMPLES
[0029] The present invention is described in further detail by showing the examples thereof, which examples however are merely intended to be illustrative and not to be construed as limiting the scope of the invention.
Example 1
[0030] To an aqueous solution of basic aluminum chloride (aluminum content: 70 g/1, Al/Cl=1.8 (atomic ratio)) was added silica sol so that the finally obtained alumina fibers would have a composition of Al 2 O 3 :SiO 2 =72:28 (by weight). After further adding polyvinyl alcohol, the mixed solution was concentrated to prepare a spinning solution having a viscosity of 40 poises and an alumina/silica content of about 30% by weight, and spinning thereof was carried out with this spinning solution according to the blowing method. A spinning air stream carrying the thus formed alumina fiber precursor was let impinge against a metal gauze-made endless belt, thereby capturing and amassing the alumina fiber precursor to obtain a 1,050 mm wide thin sheet thereof with a basis weight of 40 g/m 2 , which was relatively non-uniform and had the alumina fiber precursor arranged randomly in the plane.
[0031] This thin sheet of alumina fiber precursor was folded and stacked using a folding device of a structure shown in FIG. 1 to produce a continuous 950 mm wide laminated sheet of alumina fiber precursor comprising 63 layers of folded lamina sheet. This laminated sheet was calcined by first placing it under 300° C. for 2 hours, then successively raising the temperature to 300˜550° C. at a rate of 2° C./min and then to 550˜1,250° C. at a rate of 5° C./min, and finally leaving it under 1,250° C. for 30 minutes to make a continuous alumina fiber sheet measuring about 25 mm in thickness and about 650 mm in width. This alumina fiber sheet was cut to a width of 600 mm and both end portions comprising the turnups were removed. A 2,000 mm portion of this alumina fiber sheet was divided into 6 equal sections in the width direction and into 20 equal sections in the longitudinal direction, and the basis weight of each section was measured. The mean value of basis weight in the width direction of the longitudinally eicosasected sections and the tripled value (3σ/mean value of basis weight×100; %) of its standard deviation were determined. The scatter determined by averaging the determinations in the longitudinal direction (n=20) was 7.7%.
Comparative Example 1
[0032] A thin lamina sheet obtained according to the same procedure as in Example 1 was wound around a round rotator to produce a 1,050 mm wide laminated sheet of alumina fiber precursor comprising 63 layers of the lamina sheet, and this laminated sheet was calcined to obtain an approximately 40 mm thick and approximately 740 mm width alumina fiber sheet. This alumina fiber sheet was cut to a width of 600 mm and subjected to the same test as said above. The scatter determined in the same way as in Example 1 was 17.4%.
Example 2
[0033] A thin lamina sheet with a basis weight of 40 g/m 2 and a width of 1,050 mm obtained in the same way as in Example 1 was folded, stacked and separated at a higher rate than in Example 1 to produce a 950 mm wide continuous laminated sheet of alumina fiber precursor comprising 30 layers of the lamina sheet. To this laminated sheet was sprayed 30 ml/kg of a 10 wt % higher fatty acid ester/mineral oil solution as a lubricant, after which the sheet was subjected to needling at a rate of 5 stitches/cm 2 and then calcined in the same way as in Example 1 to make a continuous alumina fiber sheet having a thickness of about 10 mm and a width of 650 mm. Evaluations of this alumina fiber sheet by the same method as used in Example 1 showed a scatter of 6.7%.
[0034] In order to evaluate suitability of the obtained alumina fiber sheet for use as a holder for exhaust gas cleaning systems, five 50 mm×50 mm square test pieces were collected from the sheet by cutting it in the width direction at equal intervals, and each test piece was subjected to 5-time repetition of a compression/release operation which comprised compressing the test piece to a thickness of 4 mm at room temperature by a compression tester, measuring the surface pressure and then releasing the compression. Each test piece was also subjected to 5-time repetition of a compression/release operation which comprised compressing the test piece to a thickness of 3 mm, measuring the surface pressure and releasing the compression. The results of the above evaluation tests are shown in Table 1.
Comparative Example 2
[0035] A thin lamina sheet obtained in the same way as in Comparative Example 1 was wound around a round rotator to produce a 1,050 mm wide laminated sheet of alumina fiber precursor comprising 30 layers of the said lamina sheet, and this laminated sheet was needled and calcined as in Example 1 to obtain an alumina fiber sheet having a thickness of about 10 mm and a width of about 740 mm. The scatter of this alumina fiber sheet as determined in the same way as described above was 16.8%.
[0036] Suitability of the obtained alumina fiber sheet for use as a holder for exhaust gas cleaning systems was evaluated in the same way as in Example 2, the results are shown in Table 1. Comparing Example 2 and Comparative Example 2, both are high in surface pressure, which is little reduced even if thickness alteration is repeated, and both are also high in restorative force of fibers and suited for use as a holder. However, it is remarkable that Example 2 is small in scatter of surface pressure properties between the sheets than Comparative Example 2, and particularly suited for use as a holder material.
TABLE 1 Example 2 Comp. Example 2 Compression thickness 4 mm 3 mm 4 mm 3 mm Surface pressure (after 1st/5th application of compression, kg/cm 2 ) Test piece 1 1.5/1.3 3.9/3.8 1.0/1.0 2.8/2.8 Test piece 2 1.4/1.3 3.7/3.7 1.6/1.5 3.9/3.8 Test piece 3 1.6/1.5 4.0/3.9 1.1/1.0 2.9/2.8 Test piece 4 1.5/1.4 3.8/3.7 1.7/1.5 4.3/4.1 Test piece 5 1.6/1.5 4.1/4.0 2.5/2.1 5.2/4.7 | The present invention relates to a process for producing a laminated sheet comprising an alumina fiber precursor, which process comprises spinning out an alumina fiber precursor from a solution mainly comprising an aluminum compound, falling and stacking said alumina fiber precursor on the surface of an accumulator to form a thin lamina sheet of alumina fiber precursor, continuously pulling out said lamina sheet from the accumulator, transferring the resultant lamina sheet to a folding device, and folding the sheet by a predetermined width while stacking the folded sheet and continuously moving the stacking sheet in the direction orthogonal to the folding direction. | 3 |
RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 60/866,301, filed on Nov. 17, 2006, the disclosure of which is hereby incorporated herein in its entirety.
BACKGROUND OF THE INVENTION
Unprotected metal surfaces can suffer severe corrosion when exposed to the environment. To protect metal surfaces from corrosion, the surfaces are often treated with various corrosion inhibitors, such as zirconium or chromium compounds, as well as phosphates such as iron phosphate and zinc phosphate. Each of these corrosion inhibitors has disadvantages such as inadequate protection of the metal surface from the environment, expense, toxicity, and not being environmentally friendly. There is a need for a corrosion inhibitor that offers greater protection than the currently available corrosion inhibitors.
SUMMARY OF THE INVENTION
The present invention is premised on the realization that organofunctional siloxane oligomers applied to metal surfaces function as more effective corrosion inhibitors than the inhibitors currently available on the market. In particular, an aqueous solution containing a small percentage of organofunctional siloxane oligomers is particularly effective as anticorrosion treatments for metal surfaces. The organofunctional siloxane oligomer is applied to a clean metal surface and allowed to dry. Then, optionally, a topcoat may be applied onto the organofunctional siloxane oligomer treated metal surface.
The siloxane oligomers can be used in combination with other mono- and bis-functional silanes to further enhance corrosion protection.
The objects and advantages of the present invention will be further appreciated in light of the following detailed description.
DETAILED DESCRIPTION
The coating composition utilized in the present invention is an aqueous-based coating composition that includes an organofunctional siloxane oligomer.
Organofunctional siloxane oligomers for use in the present invention include the group of spherosilicates known as silsesquioxanes. Silsequioxanes are polycyclic compounds formed from silicon and oxygen atoms with at least one silicon atom covalently linked to an organofunctional group. Silsesquioxanes can be fully or partially hydrolyzed. Fully hydrolyzed silsesquioxanes have the general formula [RSiO 1½ ] 2n , where R is an organofunctional group. The oxygen ratio is increased in partially hydrolyzed silsesquioxanes such as, for example, trisilanols, and tetrasilanols.
The organofunctional groups included with the siloxane oligomers of the present invention include any group that is compatible with subsequent coating compositions. For example, amino substituted silsesquioxanes are particularly compatible with subsequent epoxy and polyester coatings. Examples of organofunctional groups contemplated in the present invention include alkyl and alkoxy groups and at least one additional organofunctional group such as amino, ureido, epoxy, vinyl, cyanato, urethane, methacrylato, isocyanate, acrylato, sulfane, or mercapto functionalities. Organofunctional oligomers can also be formed from organofunctional silanes reacted with nonfunctional silanes.
The organofunctional siloxane oligomers for use in the present invention include commercially available fully hydrolyzed linear silsesquioxanes and partially hydrolyzed silsesquioxanes, such as for example, tetrasilanols and trisilanols. Examples of siloxane oligomers are aminosilsesquioxane, aminopropylsilsesquioxane oligomer, aminopropylsilsesquioxane-methylsilsesquioxane, which is a copolymer oligomer, and 3((2-aminoethyl)amino)propyl)silanetriol homopolymer. Additional commercially available siloxane oligomers, such as for example, aminopropylsilsesquioxane-vinylsilsesquioxane, are available for use in the present invention.
The organofunctional siloxane oligomers for use in the present invention should have a molecular weight in the range of about 250 to about 650. Preferably, the molecular weight of the organofunctional siloxane oligomers is less than about 500.
The aqueous solution of organofunctional siloxane oligomer is made by diluting the desired amount of organofunctional siloxane oligomer in deionized water and adjusting the pH with an acid or a base. Specifically, the organofunctional siloxane oligomer of the present invention is diluted in deionized water in a range of about 0.01 wt.-% to about 10 wt.-%. In one embodiment, the organofunctional siloxane oligomer is diluted in the aqueous solution in a range of about 0.02 wt.-% to about 2 wt.-%. In another embodiment, the organofunctional siloxane oligomer is diluted in the aqueous solution to about 0.05 wt.-% to about 1 wt.-%.
The pH of the aqueous solution should be slightly acidic to alkaline. The pH of the solution may be adjusted with any acid or base known in the art such as, for example, acetic acid or sodium hydroxide. The pH is preferably in a range from about 5 to about 12, and more preferably, from about 10 to about 12.
The aqueous solution of organofunctional siloxane oligomers can optionally include additional corrosion inhibitors. For example, zirconium, chromium, and zinc-phosphate based corrosion inhibitors may be dispersed in the aqueous solution as desired. These compounds should be added to the aqueous solution of organofunctional siloxane oligomers in quantities sufficient to inhibit corrosion of metal surfaces or promote passivation as is known in the art.
The aqueous solution of organofunctional siloxane oligomer of the present invention can be used to treat any metal surface that requires protection from corrosion. Examples of metal surfaces that can be utilized with this method include steel, stainless steel, cold rolled steel, galvanized steel, galvanneal, iron, aluminum, alloys of these metals, and others. The metal surface may optionally be treated with a standard corrosion inhibitor or passivation agent used in industry prior to application of the aqueous solution containing the organofunctional siloxane oligomer. The standard corrosion inhibitors or passivation agent should be applied to metal surfaces as known in the art. Examples of standard pretreatments for metals are zinc phosphate, iron phosphate, fluorotitanic acid, fluorozirconic acid and combinations thereof. Another example of a pretreated metal is anodized aluminum. Examples of passivation agents include silane-containing compounds such as, for example, bis-[triethoxysilyl]ethane.
To apply the coating of the present invention, the metal surface to be treated is first cleaned. The metal surface can be cleaned with any material known in the art such as, for example, an alkaline cleaner. The metal surface is then rinsed with water and allowed to dry.
The aqueous solution of organofunctional siloxane oligomers can be applied to the metal surface by any method known in the art that is used to apply a liquid to a surface such as, for example, dip coating, spraying, rolling, or brush application. The metal surface is exposed to the organofunctional siloxane oligomer for about 1 second to about 60 seconds, preferably for about 3 seconds to about 30 seconds. Generally the metal surface is exposed to organofunctional siloxane oligomer for about 5 seconds to about 10 seconds.
After coating with organofunctional siloxane oligomer, the metal surface is allowed to dry at room temperature. The surface can also be dried at an elevated temperature such as, for example, at about 100° C. for about 5 minutes.
After coating with the aqueous solution of organofunctional siloxane oligomer, a topcoat may be applied to the metal surface. The topcoat can be any coating known in the art that is used on metal. For example, the topcoat can be any organic solvent or water dispersed polymerizable coating composition including primers, pigment containing paints, as well as clear coats. In addition, powder coating techniques may be used. Exemplary topcoats include polyurethanes, acrylates or methacrylates, epoxies, or polyesters.
In a further embodiment, the organofunctional siloxane oligomer can be combined with an organofunctional silane. Suitable organofunctional silanes include amino silanes, vinyl silanes, bis-functional amino silanes, polysufide silanes, epoxy silanes, ureido silanes and isocyanato silanes, as well as mixtures thereof. Such silanes are disclosed in U.S. Pat. No. 6,416,869; U.S. Pat. No. 6,756,079; PCT application WOP2004/009717; pending application U.S. 2005/0058843; and U.S. Pat. No. 6,919,469, the disclosures of which are hereby incorporated by reference.
Suitable monofunctional silanes include: vinylethoxysilane, gamma-methacryloxypropyltrrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-ureidopropyltrimethoxysilane and gamma-isocyanatopropyltriethoxysilane.
In addition to using straight monomeric silanes, a mixture of monomeric silanes can be employed, in particular, a blend of aminosilane in combination with vinyl silane has been found to be particularly advantageous. A ratio of 5:1 volume/volume of bis-aminosilane and vinyl silane is particularly beneficial, as is discussed below.
Bis-silyl aminosilanes which may be employed in the present invention have two trisubstituted silyl groups, wherein the substituents are individually chosen from the group consisting of alkoxy, aryloxy and acyloxy.
The ratio of organofunctional silane to oligomer can vary from 10:1 to 1:10 by volume.
The present invention will be further appreciated in light of the following detailed examples.
Example 1
The following metal pretreatments were tested as a replacement for conventional iron phosphates and its corresponding sealers. Conventional metal surface anti-corrosion pretreatment require a step in which the corrosion inhibitor is sealed. An additional benefit with organofunctional siloxane oligomer pretreatments is that the conventional sealing step is omitted.
Solutions preparation: Aqueous solutions of organofunctional siloxane oligomers were prepared by adding 2 volume parts of the following individual chemicals into 95 volume parts of de-ionized water (hereinafter “DI water”). 3 volume parts of 1 N sodium hydroxide solution were added into the above solution for pH adjustment. The final pH was 11.
The organofunctional siloxane oligomer used in these examples include: methoxy terminated aminosilsesquioxanes (hereinafter “Z-6184”, available from Dow Corning in >60 wt.-% solution), 3-((2-aminoethyl)amino)propyl)silanetriol homopolymer (hereinafter “Z-6137”, available from Dow Corning in a 15 wt.-% to 40 wt.-% solution), aminopropylsilsesquioxane-methylsilsequioxane copolymer oligomer, (hereinafter “AMME”, available from Gelest Inc. in a 22 wt.-% to 25 wt.-% solution) and aminopropylsilsesquioxane oligomer (hereinafter “AM”, available from Gelest Inc. in a 22 wt.-% to 25 wt.-% solution).
The practical usage level of the above solutions is normally below 2 wt.-%. Therefore, the final concentration was obtained simply by dilution of the above 2 wt.-% solutions.
Substrate: Cold rolled steel panels (hereinafter “CRS”, from ACT Laboratories) were cleaned with a 7 wt.-% Chemclean (purchased from Chemetall/Oakite Inc) at 60° C., followed by tap water rinsing and blow air drying.
Application and drying: The cleaned CRS panels were immersed into the aqueous solutions of organofunctional siloxane oligomers with the concentrations of 0.5 wt.-%, 0.25 wt.-%, 0.1 wt.-% and 0.05 wt.-% for 5 to 10 seconds, followed by 100° C. drying for 5 minutes.
Topcoats: Two Morton® powder coatings, (1) Corvel sky white, polyester; and (2) epoxy black (available from Rohm & Haas), were applied onto the organofunctional siloxane oligomer pretreated CRS panels.
Test: Powder painted CRS panels were then scribed and were exposed to salt spray test (hereinafter “SST) according to ASTM B117. The creepages of the coatings were examined periodically.
Results: Table 1 displays a 500-hr SST result for polyester powder painted CRS panels with different pretreatments and epoxy-powder painted CRS panels after SST. It is clearly seen in Table 1 that organofunctional siloxane oligomer pretreatments perform very well without sealer. The organofunctional siloxane oligomer pretreatment after 400 hrs in SST even outperforms the control which utilize commercial iron phosphate pretreatment followed by a non-chrome sealer after only 250 hrs in SST. The nonpretreated control showed complete delamination (Del) after 500 hours in SST.
TABLE 1
Pretreatment
100 hr
190 hr
300 hr
450 hr
500 hr
0.5 wt.-% AM
<0.5
1
2
3
3.5
0.25 wt.-% AM
<0.5
0.75
1.5
3
3.5
0.2 wt.-% AM
<0.5
0.75
1.5
3.5
3.5
0.1 wt.-% AM
<0.5
0.5
<1.5
2.5
2.5
0.05 wt.-% AM
<0.5
0.5
<1.5
3
3
0.5 wt.-% AMME
0
0
<1.5
<2
2
0.25 wt.-% AMME
0
<0.5
<1.5
1.5
2
0.2 wt.-% AMME
<0.5
0.5
1
2.5
2.5
0.1 wt.-% AMME
<0.5
<0.5
<1.5
3.5
3.5
0.05 wt.-% AMME
0.5
1
2
3.5
3
0.5 wt.-% Z-6184
1
1.5
2
4
4
0.25 wt.-% Z-6184
<1
1
2.5
3.5
4.5
0.2 wt.-% Z-6184
<1
<1.5
2.5
3.5
4.5
0.1 wt.-% Z-6184
0.5
<1
2.5
3.5
3.5
0.05 wt.-% Z-6184
0.5
<0.5
2
2
3.5
Example 2
The following metal pretreatments were tested as a replacement for conventional hexavalent chromium pretreatment in the coil industry.
Solutions preparation: Aqueous solutions of organofunctional siloxane oligomers were prepared by adding 2 volume parts of the following individual chemicals into 95 volume parts of DI water. The solution pH was adjusted by the addition of 3 parts acetic acid. The final pH was 6.
The organofunctional siloxane oligomers used in this example include: Z-6184, Z-6137, AMME, and AM.
The practical usage level of the above solutions is normally below 2 wt.-%. Therefore, the final concentration was obtained simply by dilution of the above 2 wt.-% solutions.
Substrate: Hot-dip galvanized steel panels (hereinafter “HDG”, from PPG Industries) were cleaned with a 7 wt.-% Chemclean (purchased from Chemetall/Oakite Inc) at 65° C., followed by tap water rinsing and blow air drying.
Application and drying: The cleaned HDG panels were immersed into the above organofunctional siloxane oligomer solutions with the concentration of 0.5 wt.-% for 5 to 10 seconds, followed by 100° C. drying for 5 minutes.
Primers: Two chromate-containing solvent-borne primers (from PPG), 1 PLY 5823 and 1 PLY 5440, were applied onto the above treated HDG panels with a #30 draw down bar. The curing condition was 150° C. for 5 minutes. The dry film thickness was around 15 microns.
Topcoat: A solventborne polyester topcoat (Polydure® 5000 Torres Blue S/G), was drawn down onto the above primed HDG panels with a #30 draw down bar. The curing condition was 150° C. for 20 minutes. The dry film thickness was around 15 microns.
Test: Polyester topcoated HDG panel surfaces were then scribed and were exposed to SST according to ASTM B117. The creepages of the coatings were examined periodically.
Results: Table 2 displays a 500-hr SST result for polyester painted HDG with different pretreatments. In Table 2, AM and Z-6184 show the best results, i.e., no creepage, after 500 hrs in SST.
TABLE 2
Pretreatment
Primer
Creepage (mm)
AM (0.5 wt.-%)
1 PLY 5440
0
AMME (0.5 wt.-%)
1 PLY 5440
0.5
Z-6137 (0.5 wt.-%)
1 PLY 5440
1
Z-6184 (0.2 wt.-%)
1 PLY 5440
0
AM (0.5 wt.-%)
1 PLY 5823
NA
AMME (0.5 wt.-%)
1 PLY 5823
0.5
Z-6137 (0.5 wt.-%)
1 PLY 5823
Del
Z-6184 (0.2 wt.-%)
1 PLY 5823
1
NONE
1 PLY 5823
Del
Example 3
The following metal pretreatments were tested as a replacement for conventional zinc phosphate based pretreatment that is used in the automotive industry.
Solutions preparation: An aqueous solution of organofunctional siloxane oligomer was prepared by adding 1 volume parts of the following individual chemicals into 99 volume parts of DI water.
AMME is the organofunctional siloxane oligomer used in this example.
Substrate: Sand-blasted high-strength carbon steel coils were cleaned with a 7 wt.-% Chemclean (purchased from Chemetall/Oakite Inc) at 65° C., followed by tap water rinsing and blow air drying.
Application and drying: The AMME solution was spray-applied onto the cleaned steel coils, followed by 100° C. drying for 5 minutes.
Topcoat: An epoxy powder was applied onto the above steel.
Test: The epoxy powder painted steel coil surfaces were then scribed and were exposed to GM 9505P Environmental Cycle J-5 cycles.
Results: Table 3 displays the test results for epoxy powder painted carbon steel coils after GM 9505 Environmental Cycle J-5 cycles. It is clear in Table 3 that AMME pretreatment performed equally well as a conventional zinc phosphating process. This indicates that organofunctional siloxane oligomer pretreatments have a potential to be a viable replacement of pretreatment of metal surfaces with Zinc phosphate.
TABLE 3
Pretreatment
Creepage (mm)
AMME, 1 wt.-%
7.8
Zn-phosphate
8.4
Alkaline-cleaned only
18.4
Example 4
The following metal treatments were tested as sealers or post rinses of metal surfaces having a zirconium-based treatments as used in general industry.
Solutions preparation: Aqueous solutions of organofunctional siloxane oligomers were prepared by adding 2 volume parts of the following individual chemicals into 95 volume parts of DI water. 3 volume parts of 1 N sodium hydroxide solution were added into the above solution for pH adjustment. The final pH was 11.
The organofunctional siloxane oligomers used in this example include: AMME and AM.
The practical usage level of the above solutions is normally below 2 wt.-%. Therefore, the final concentration was obtained simply by dilution of the above 2 wt.-% solutions.
Substrate: Zirconium treated cold-rolled steel (hereinafter “CRS”).
Application and drying: The zirconium treated CRS panels were immersed in the above organofunctional siloxane oligomer solutions at different concentrations, ranging from 0.01 wt.-% to 0.25 wt.-% by volume for 5 to 10 seconds, followed by 100° C. drying for 5 minutes.
Topcoat: A solvent borne polyester topcoat was drawn down onto the above treated CRS panels with a #50 draw down bar. The curing condition was 160° C. for 20 minutes. The dry film thickness was around 35 microns.
Test: Polyester topcoated CRS panel surfaces were then cross cut and were exposed to a salt spray test (SST) according to ASTM B117. The creeps of the coatings from the scribes were examined after 120 hrs in SST.
Results: Table 4 displays a 120-hr SST result for polyester painted CRS with different organofunctional siloxane oligomer sealers. It is clearly seen in table 4 that the zirconium-treated CRS panels show better performance (i.e., smaller creeps) after organofunctional siloxane oligomer post-rinsing than the panel without any organofunctional siloxane oligomer post rinses.
TABLE 4
Pretreatment
Creepage (mm)
AMME (0.25 wt.-%)
2.8
AMME (0.1 wt.-%)
8
AMME (0.05 wt.-%)
10
AMME (0.01 wt.-%)
9
AM (0.25 wt.-%)
2.8
AM (0.1 wt.-%)
3.1
AM (0.05 wt.-%)
7.5
AM (0.01 wt.-%)
>15
Zr treatment ONLY
>15
Example 5
The following metal pretreatments were tested as sealers or post rinses for conventional iron phosphating used in general industry.
Solutions preparation: Aqueous solutions of organofunctional siloxane oligomers were prepared by adding 2 volume parts of the following individual chemicals into 95 volume parts of DI water. The solution pH was adjusted by sodium hydroxide. The final pH was 11.
The organofunctional siloxane oligomers used in this example included AMME and AM.
The practical usage level of the above solutions is normally below 2 wt.-%. Therefore, the final concentration was obtained simply by dilution of the above 2 wt.-% solutions.
Substrate: Iron phosphate treated cold-rolled steel (CRS).
Application and drying: The iron phosphated CRS panels were immersed in the above organofunctional siloxane oligomer solutions at different concentrations, ranging from 0.01 wt.-% to 0.25 wt.-% for 5 to 10 seconds, followed by 100° C. drying for 5 minutes.
Topcoat: An epoxy-polyester hybrid powder paint was applied onto the above treated CRS panels. The curing condition was 177° C. for 15 minutes. The dry film thickness was around 50 microns.
Test: Powder painted CRS panels were then cross cut and were exposed to a salt spray test (SST) according to ASTM B117. The creepage of the coatings from the scribes was examined after 230 hrs in SST.
Results: Table 5 displays a 230-hr SST result for polyester painted CRS with different organofunctional siloxane oligomer sealers. It is clearly seen in Table 5 that the organofunctional siloxane oligomer post rinses at certain concentrations enhance the coating performance of the organofunctional siloxane oligomer rinsed panels as compared to the panel without organofunctional siloxane oligomer post rinsing.
TABLE 5
Pretreatment
Creepage (mm)
AMME (0.25 wt.-%)
2
AMME (0.1 wt.-%)
3.5
AMME (0.05 wt.-%)
5
AMME (0.01 wt.-%)
7
AM (0.25 wt.-%)
2
AM (0.1 wt.-%)
2.5
AM (0.05 wt.-%)
6.5
AM (0.01 wt.-%)
6
Fe PO 4 treatment ONLY
7
Example 6
The following metal pretreatments were tested as passivation treatments of hot dip galvanized steel (“HDG”) for white rust prevention in coil industry.
Solutions preparation: Mixed solutions of AMME and bis-[triethoxysilyl]ethane (hereinafter “BTSE”, available from GE Silicones) were prepared by adding 5 wt.-% AMME solution into 5 wt.-% BTSE aqueous solution at different volume rations (see Table 6).
Substrate: Bare hot dip galvanized steel (from CORUS).
Application and drying: The HDG panels were immersed into the above mixed solutions for 5 to 10 sec, followed by 100° C. drying for 30 min.
Test: 3.5 wt.-% NaCl neutral salt immersion test was conducted on the above treated HDG panels. The exposure time was 4 days.
Results: Table 6 displays a 4-day salt immersion test result for the treated HDG panels. It is clearly seen in Table 6 that HDG panels treated with the system of BTSE/AMME (5 wt.-%, 3/1) show the best corrosion prevention performance (i.e., no white rust) after 4 days of immersion in a 3.5 wt.-% NaCl solution.
TABLE 6
BTSE:AMME
HDG surface appearance after 4 days of salt immersion
BTSE-only
A little white rust at the edges and along the water line
9:1
A little white rust at the edges and along the water line
7:1
Slight white rust at the edges and along the water line
5:1
Slight white rust at the edges and along the water line
3:1
No white rust
1:1
Slight white rust at the edges and along the water line
1:3
Slight white rust at the edges and along the water line
1:5
Considerable amount of white rust along the water line
1:7
Considerable amount of white rust along the water line
1:9
Considerable amount of white rust along the water line
AMME-only
Heavy white rust at the edges and along the water line
As shown, a 3:1 volume ratio of BTSE to AMME performed best.
As shown in the above examples and general description, the present invention provide the advantage of offering greater protection to metal surfaces from corrosion than conventional corrosion inhibitors. In addition, the organofunctional siloxane oligomers are in an aqueous solution, reducing the amount of solvents used in the metal coating process.
This has been a description of the present invention along with the preferred method of practicing the present invention. However, the invention itself should only be defined by the appended claims, wherein we claim: | A method of applying to a clean metal surface an aqueous solution comprised of a small percentage of organofunctional siloxane oligomers. The organofunctional siloxane oligomers used in this method include silsesquioxanes. The organofunctional siloxane oligomers are applied to a metal surface prior to the application of a topcoat and function to inhibit corrosion of the metal surface. | 2 |
BACKGROUND OF THE INVENTION
Humans have been applying tattoos to the skin for over 8000 years. The inks and dyes used were historically derived from substances found in nature and comprise a heterogeneous suspension of pigmented particles and other impurities. A well-known example is India ink, a suspension of carbon particles in a liquid.
Tattoos are typically produced by applying, with tattoo needles, tattoo ink into the dermis, where the ink remains permanently. This technique introduces the pigment suspension through the skin by an alternating pressure-suction action caused by the elasticity of the skin in combination with the up-and-down movement of the tattoo needles. Water and/or other carriers for the pigment introduced into the skin diffuse through the tissues and are absorbed. The insoluble pigment particles remain in the dermis where they were initially placed, for the most part. Inks used for tattooing resist elimination by virtue of their inertness and the relatively large size of the insoluble pigment particles. A tattoo produced in this manner will partially fade over time but will generally remain present throughout the life of the tattooed person.
Tattoos are used for a variety of reasons, primarily for ornamentation of the skin. While tattoos have traditionally been applied as designs for the skin, they are also used for permanent cosmetics, such as eyeliner and lip color often by people who cannot apply makeup, such as those suffering from arthritis or Parkinson's disease. Additionally, for breast reconstruction after mastectomy, it is desirable to reconstruct the nipple and areola area with darker flesh tone tattooing in order to produce a natural-looking breast. Moreover, tattooing has been used to treat hypo- and hyper-pigmentation caused by vitiligo, skin grafts, port-wine stains, and other dermatologic conditions.
Quite often people have a change of heart after being tattooed. For example, a person may desire to remove or change the design of a decorative tattoo, such as the name of an old girl friend after the tattooed persons marries someone else. Alternatively, an individual with cosmetic tattooing, such as eyeliners, eyebrows, or lip coloring, may wish to change the color or area tattooed as fashion changes. In addition, following breast reconstruction, the geometry of the breast may change over time, leading to a tattooed nipple changing from an aesthetically pleasing position to an unpleasant one.
Unfortunately, there is currently no simple and completely successful way to remove tattoos. Removal by surgical excision, dermabrasion, requires invasive procedures associated with potential complications, such as infections, and usually results in conspicuous scarring. Removal by laser therapy is the most common technique and is usually limited to eliminating only from 50–70% of the tattoo pigment, resulting in a residual smudge. Laser removal requires multiple treatment sessions (usually five to twenty) with expensive equipment for maximal elimination. Thus, the overall cost of laser removal is generally prohibitively expensive for many people. Additionally, most tattooing inks are made of pigments which have a wide range of particle size. If the pigment particles are small, they may diffuse through the tissues, causing “bleeding” of the color, “blurring” of the lines of the tattoo, or partial fading of the tattoo.
Prior art temporary substitutes for tattoos are unsatisfactory because they tend to be very short-lived. If only the surface of the skin is colored, such as by painting on the skin, the ornamentation is easily removed by wetting or rubbing the skin or by the natural sloughing of epidermis every three to four weeks. While this technique produces only temporary skin ornamentation, it would be desirable to have the option to color the skin to last longer than a few hours, days, or weeks.
The epidermis, 39 in FIG. 1 and FIG. 1A of the human skin comprises several distinct layers of skin tissue. The deepest layer is the stratum basale layer which consists of columnar cells. The next layer up is the stratum spinosum composed of polyhedral cells. Cells pushed up from the stratum spinosum are flattened and synthesize keratohyalin granules to form the stratum granulosum layer. As these cells move outward they lose their nuclei and the keratohyalin granules fuse and mingle with tonofibrils. This forms a clear layer called the stratum lucidum. The cells of the stratum lucidum are closely packed. As the cells move up from the stratum lucidum they become compressed into many layers of opaque squamas. These flattened cells have become completely filled with keratin and have lost all other internal structure, including nuclei. These squamas constitute the outer layer of the epidermis, the stratum corneum. At the bottom of the stratum corneum the cells are closely compacted and adhere to one another strongly, but higher in the stratum they become loosely packed and eventually flake away at the surface. Also shown in FIG. 1 is hair stem 33 sebaceous gland 38 , hair duct 31 , nerve ending 34 , veins and arteries 36 and 37 , sweat gland 35 and pupilla 32 .
It is known that graphite vaporizes at about 3,600.degrees. C. It is known that graphite is a strong absorber of infrared light and that infrared light such as the 1.06 micron laser beam produced by the Nd:YAG laser will penetrate several millimeters through human skin. It is also known that short pulses of light energy absorbed by a strongly absorbing material can result in shock waves creating mechanical forces.
What is needed is a better method for applying tattoo quickly and without needles and pain.
SUMMARY OF THE INVENTION
The present invention provides a light-triggered tattoo process. A strong absorber of light energy and tattoo material are sandwiched under pressure between a skin region and a transparent window. Short pulses of light, at frequencies strongly absorbed by the strong absorber, illuminates the strong absorber through the window creating micro-explosions in the strong absorber that drive particles of the tattoo material into the skin region producing a tattoo.
In a preferred embodiment the strong absorber is small particles of graphite, such as the graphite particles in India ink. The graphite is printed on a transparent substrate such as an overhead transparency. A thin layer of tattoo material is applied over the graphite particles. The transparent substrate is pressed firmly against a skin region with the tattoo material and the graphite particles sandwiched between the skin and the transparency. The transparency functions as the window. Pulsed laser beams are directed through the transparent substrate and absorbed by the graphite to produce thousands of micro-explosions in the graphite and the explosions drive tattoo material into the epidermis layers of the skin. In preferred embodiments the tattoo material may be printer color ink. For black portions of tattoos the tattoo material can be the same graphite particles functioning as the strong absorber.
Very high quality tattoo patterns can be prepared quickly and easily using modern color printer/copiers. The tattoos can be applied safely to the skin of a patient in a matter of a few minutes or even seconds with no pain. In these preferred embodiments a glass plate may be applied on top of the transparency substrate to provide uniform pressure in the region between the substrate and the skin. In this case both the glass plate and the transparency functions as the window. A preferred light source is a Nd-YAG laser operating at a 1.06 micron wavelength with short pulses in the range of a 100 to 300 microseconds with repetition rates up to a few hundred Hz. Shorter pulses in the range of a few nano-seconds can also be utilized, but care must be taken to control the pulse energy so that the tattoo material is not vaporized. Many other short pulse light sources could be utilized including a wide variety of short pulse lasers and flash lamps, such as xenon flash lamps. Tattoos in preferred embodiments are limited to depths of about 100 to 200 microns in the epidermis and are not permanent. In addition, if desired, they can be quickly removed using a variety of techniques such as the same Nd-YAG laser operating at increased power density.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 1A show the composition of human skin.
FIG. 2 shows layers of the epidermis.
FIG. 3 shows how black ink (comprised of graphite particles) is applied to a transparency by a modern color printer to produce a gray color.
FIG. 4 shows a cross section of a gray transparency with rows of graphite particles.
FIG. 5 shows the gray transparency with a layer of color (such as red) ink covering the graphite rows.
FIG. 6 shows a setup in preparation to applying a color tattoo.
FIG. 6A shows graphite particles exploding to force color ink into the epidermis region of the skin.
FIG. 7 shows color particles distributed in the epidermis.
FIG. 8 shows a cross section of a transparency with a 1 mm wide black line printed on it.
FIG. 9 shows a setup in preparation for a black line tattoo.
FIG. 9A shows graphite particles exploding to force graphite particles into the epidermis region of the skin.
FIG. 10 shows the graphite distributed in the epidermis.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Applicants discovered some time ago that when small particles of graphite are illuminated with very short pulses of laser light of sufficient energy the individual particles explode violently. If the pulse-duration and energy is chosen correctly graphite particles in the sub-micron size range will violently break apart into smaller fragments. Subsequent pulses continue to break the particles into even smaller sizes until the particles disappear. For example, in an inert atmosphere after repeated illumination with 1.06 micron, 12 nanoseconds, 3 Joules per cm 2 pulses, the particles are broken into extremely small particles barely visible to the unaided eye. But in air the particles after such repeated illumination disappear completely, apparently forming CO 2 .
The present invention utilizes the micro-explosive force (created by the partial or complete vaporization of small particles due to the absorption of light energy in very short time intervals) to force black and/or color ink particles into the epidermis region skin tissue.
First Embodiment—Color Application
A first preferred embodiment of the present invention can be described by reference to FIGS. 2 through 8 .
FIG. 2 shows layers of the epidermis as discussed in the Background section. The epidermis is typically a few hundred microns thick. The purpose of the present invention is to deposit beautiful color patterns in the epidermis region of the skin quickly and painlessly using lasers to produce micro explosions to drive the tattoo ink into this region of the skin.
In this embodiment a color printer/copier is used to prepare a color tattoo pattern. FIG. 3 shows how black ink (comprised of graphite particles) is applied to a transparency (such as Xerox laser/copier transparencies, Model 3R3108) by a modern color printer to produce a gray color. In a modern color printer/copier such as the Xerox Docucolor 12, colors are laid down in rows as shown in FIG. 3 . Applicants count 5 rows per millimeter, so that the rows are on 200 micron centers. Dark to light control is produced by making the lines thicker. At the dark setting the lines tend to meet each and blur together to produce a solid pattern. The pattern shown in FIG. 3 would correspond to a light setting. If the printer/copier is set to black and white, the rows are produced with black printer ink that is basically small graphite particles. As indicated above these small graphite particles explode when illuminated with very short pulses of laser infrared light at (for example) a wavelength of 1.06 micron. FIG. 4 shows a cross section of a gray transparency with rows of graphite particles. Next a color pattern is copied over the graphite rows on the transparency. FIG. 5 shows the gray transparency with a layer of color (such as red) ink covering the graphite rows. Next the transparency is placed on the skin to be tattooed with the color layer sandwiched between the skin and the transparency. And a glass plate is placed over the transparency to apply pressure on the skin to hold the color layer tightly against the skin. FIG. 7 shows the setup in preparation to applying a color tattoo. The layer is then illuminated with short pulses of the laser light to explode the graphite particles. Applicants' best results using an Nd-YAG laser were with 300 micro-second pulse-width pulses operating at 250 Hz. The spot size was only about 1.0 mm so the beam had to be scanned rapidly so as to not produce spot heating. FIG. 7A shows graphite particles exploding to force color ink into the epidermis region of the skin. FIG. 8 shows the result of the procedure with the color particles distributed in the epidermis. Prototype tests were performed with animal skin similar to human skin. Microscopic examination of the skin showed that the particles penetrated to about 150 microns into the skin. None of the tattoo ink would rub off with normal rubbing. To tattoo a pattern of one square centimeter onto the skin of a client could be done in about 10 seconds.
Second Embodiment—Black Patterns
A second technique for producing black tattoo patterns is shown with FIGS. 8 through 10 . In this embodiment, relatively thick black lines are printed on transparencies using the same equipment as described above. The normal settings of the printer/copier provide adequate results. The cross section of a single line, such as the cross section of an “I” that is about 1 mm wide and maybe 50 graphite particle high is shown in FIG. 8 . The tattoo could be a short phrase such as “NANCY MY LOVE” or a black outline pattern. The mirror image of the letters should be printed on the transparency. FIG. 9A shows the illumination step that is the same as above. In this case some of the graphite particles explode driving other particle into the skin. Excellent tattoos were produced with particles driven about 150 microns into the skin.
Explosive Graphite
Graphite is very absorptive of laser energy at the 1.06 micron wavelength. The latent heat of vaporization is about 10 5 J/cm 3 for cold solid graphite. (The energy required to heat room temperature graphite to the sublimation temperature is roughly 4% of the sublimation energy.) Thus, to vaporize a 1 micron cube (10 −12 cm 3 ) would require approximately 10 −7 J. The energy falling on the surface of the 1 micron particle (1×10 −8 cm 2 ) in a 3 J/cm 2 pulse is 3×10 −8 J, about one third of the energy needed to totally vaporize the particle. Therefore, a significant portion of the particle is vaporized. The energy is deposited too quickly for the heat to diffuse; therefore, the particle explodes violently upon being illuminated by the short-duration pulse. (Subsequent pulses will vaporize the smaller particles created by the earlier pulses.) The resulting forces of the tiny explosions forces a portion of the ink into the skin tissue.
OTHER TECHNIQUES AND EMBODIMENTS
The two examples described above are experiments actually performed to prove the feasibility of the present invention. Persons skilled in the arts to which this invention relates will recognize that there are many other ways to practice the present invention.
Other Light Sources
For example, numerous other lasers and wavelengths and could be utilized. In fact any technique that employees a material capable of producing micro-explosions upon illumination with very short pulsed of light to produce tattoos in the skin could be substituted for the techniques described above. This includes lasers operated with pulse durations of a few nanoseconds. Care should be taken however to tailor the pulses so that they do not vaporize the colors. Short pulse flash lamps can also be used as the light source. A good choice would be a xenon flash lamp.
Other Strong Absorbers
Many particles in addition to graphite will explode upon illumination with short laser pulses. Particles chosen, however, must have a high absorption at the wavelength of the laser chosen.
Other Tattoo Materials
The tattoo material, of course, could be tattoo ink. By matching a particular color ink to a light source highly absorbent in that ink, the ink itself can function as the strong absorber so that portions of the ink undergoes micro-explosions to drive other portions of that color into the skin. This technique is basically the technique described in the second preferred embodiment where small graphite particles function both as the absorber and the tattoo material.
Other Sandwich Techniques
Other techniques for sandwiching the strong absorber and the tattoo material between the window and the skin could be used. Instead of the printer/copier referred to in the description of the first embodiment an inkjet printer could be used to print the tattoo patterns on transparencies. In this case tattoo ink can be used in the inkjet printer (perhaps with some modifications to the printer). Instead of printing the absorber and the tattoo material on the transparent substrate (window), the tattoo material could be painted on the skin as a tattoo pattern and a strong absorber (such as India ink) could be sprayed over the pattern. A glass window could be pressed over the graphite sprayed pattern and the pattern could then be illuminated to produce tattoos similar to those described above. Alternative, the tattoo pattern could be painted on the skin and the graphite printed on a transparency as shown in FIG. 3 . With a glass plate a sandwich could then be made to create a sandwich that looks the same as the one shown in FIG. 6 .
Control Techniques
The present invention presents several opportunities to control various qualities of the tattoos produced. For example, the depth of the particle penetration can be controlled to various extents through variations of pulse energy, pulse duration, choice of strong absorber (e.g., graphite), density of absorber, pressure applied to the window against the skin region.
USES OF THE INVENTION
Applicants expect that the present invention will applied for all or substantially all of the uses to which conventional tattoos are now applied such as tattoos for skin decoration. However, since the present process is so quick, so simple, so safe, so painless and temporary, Applicants believe that its use will be far more extensive than conventional tattoo processes. A lady can have a facial make-over that will have a completely natural look in a few minutes that will last for weeks or months (instead of hours). A skin tan can be applied quickly that may last all winter. It should be feasible to tattoo an ink that is highly absorbent in the ultraviolet to reduce the risk of sunburn or skin cancer. The invention can be practice by dermatologist using existing equipment now used for treatments such as hair removal (or tattoo removal!). Some embodiments of the invention may also be practiced in traditional or up-scale tattoo parlors.
Thus, the reader should not construe the above examples as limitations on the scope of the invention, but merely as exemplifications of preferred embodiments thereof. Those skilled in the art will envision many other possible variations are within its scope. Accordingly the reader is requested to determine the scope of the invention by the appended claims and their legal equivalents, and not by the examples which have been given. | A light-triggered tattoo process. A strong absorber of light energy and tattoo material are sandwiched under pressure between a skin region and a transparent window. Short pulses of light, at frequencies strongly absorbed by the strong absorber, illuminates the strong absorber through the window creating micro-explosions in the strong absorber that drive particles of the tattoo material into the skin region producing a tattoo. | 0 |
FIELD OF THE INVENTION
The present invention relates to engines in vehicles that employ belt and pulley systems to drive some of the vehicle accessories and more particularly to pulley systems that limit the driven speed of the accessories at high engine speeds.
This application is related to a co-pending patent application titled SPEED LIMITING ACCESSORY DRIVE AND CRANKSHAFT DAMPER, filed herewith, and incorporated herein by reference.
BACKGROUND OF THE INVENTION
Conventional engines in vehicles not only provide power for the drivetrain but also provide power for accessories. Such accessories may include an air conditioning compressor, a water pump, a power steering pump, an alternator, etc. Generally, these accessories are driven by the engine via driven pulleys coupled to a driving pulley by a belt, with the driving pulley driven by the engine crankshaft. Thus, the accessories are driven at some predetermined ratio of the engine crankshaft speed, with the driving speed changing when the engine speed changes.
In today's vehicles, drivers expect that the accessories will work for all engine operating conditions. Thus, at engine idle, when the engine is generally running its slowest, and therefore the accessories are driven at their slowest speeds, the ratio of accessory driven speed to crankshaft speed must be sufficient to completely power these accessories (i.e., have adequate capacity). However, with this capacity designed-in for low engine speed conditions, when the engine is running at very high speeds (RPMs) the driving speed may be too high and overpower some accessories, creating the possibility for excessive wear of the accessories and additional noise and vibrations. Currently, for a given set of accessories, this situation requires a trade-off, then, between the minimum idle speed allowed for an engine and the maximum speed at which the engine can operate depending upon the ratio of the pulleys.
With a fixed pulley system and accessory size, possible solutions to this predicament are to either limit the minimum RPMs for engine idle conditions, thereby allowing for adequate capacity for the accessories, or to limit the upper speed (RPM) range, limiting the potential for overpowering; neither one a very satisfactory solution. The first hurts fuel economy at idle and the second would limit the engine power.
Accordingly, it is desirable to provide an accessory pulley system that will allow the accessories to be sized to handle the accessory load (adequate capacity) at low idle speeds, to increase fuel economy, while not over-driving the accessories at high engine speeds and minimizing the cost and complications needed in the pulley system to accomplish this. Furthermore, it is desirable that this system will operate automatically, without the need for external inputs, in order to minimize the complexity of the system.
SUMMARY OF THE INVENTION
In its embodiments, the present invention contemplates a speed limiting accessory drive, adapted to be rotationally driven by a crankshaft of an engine and drive engine accessories, which limits the maximum speed at which the accessories are driven. The speed limiting accessory drive includes a hub member adapted to be rotationally fixed to the crankshaft, and a housing mounted about and rotatable relative to the hub, the housing including a cavity. A pulley member is mounted on and rotationally fixed relative to the housing. A wet clutch assembly, mounted radially outward within the housing cavity, includes a plurality of friction discs and a plurality of separator plates interleaved with the friction discs, with the friction discs being rotationally fixed relative to the hub and the separator plates being rotationally fixed relative to the housing. A front cover is mounted to the housing for sealing the cavity in the housing, Biasing means are located in the cavity and rotationally fixed relative to the housing, for exerting a first force on the clutch assembly to press the separator plates into contact with the friction discs. Fluid fills the cavity in the housing, whereby the pulley member will be driven at crankshaft speed for low crankshaft rotational speeds, and the fluid will exert a second force on the biasing means opposite the first force to allow clutch slip at a maximum pulley rotational speed for high crankshaft rotational speeds. Temperature compensating means create a third force on the biasing means in the direction of the first force as the temperature of the biasing means rises.
Accordingly, an object of the present invention is to provide a speed limiting accessory drive for use in a pulley system of an engine, which limits the maximum speed at which the pulley system drives the accessories, enabling increased drive ratios for the pulley system at low engine speeds over conventional pulley systems.
An advantage of the present invention is that the engine can be made to idle at lower speeds, while still providing adequate accessory capacity at these speeds, by employing increased drive ratios for the pulley system, while still not over-driving the accessories at high engine speeds, thereby increasing the fuel economy of the vehicle.
A further advantage of the present invention is that the maximum speed of the pulley system is automatically limited without the need for operator or electronic inputs to the system.
An additional advantage of the present invention is that the accessories are driven slower at higher engine speeds, thereby increasing operating life of and reducing noise and vibrations produced by the accessories at these speeds.
A still further advantage of the present invention is that the accessories will not need to change speed on wide open throttle shifts, which eliminates belt squeal problems associated with shifts from first to second gear under wide open throttle conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial perspective view of the front of an engine with a pulley system in accordance with the present invention;
FIG. 2 is a side, sectional view of the speed limiting drive pulley assembly;
FIG. 3a is a sectional view taken along line 3a--3a in FIG. 2 and FIG. 3b is a sectional view taken along line 3b--3b in FIG. 2;
FIG. 4 is a partial front view of the pulley system with the front cover removed;
FIG. 5 is a view of the inside of the front cover of the pulley system;
FIG. 6 is a graph illustrating an example of the driven speed of an accessory versus the engine speed with and without the speed limiting drive pulley assembly;
FIG. 7 is a view similar to FIG. 2 illustrating a second embodiment of the present invention;
FIG. 8 is an exploded perspective view of the speed limiting drive pulley assembly of the alternate embodiment of FIG. 7; and
FIG. 9 is a view similar to FIG. 2 illustrating a third embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An engine 12 includes a crankshaft 14 having a speed limiting drive pulley assembly 16 attached to it, forming part of a pulley system 17. The drive pulley assembly 16 frictionally engages an accessory belt 18 mounted about it, which engages driven pulleys 20 on conventional engine accessories 22.
The speed limiting drive pulley assembly 16 includes a pulley member 24 which is affixed about a ring shaped pulley housing via a tolerance ring 27. The tolerance ring 27 serves to retain the pulley member 24 to the housing 26 and yet insulates the pulley member 24 from the temperature of the housing 26.
An outer ring portion of the housing 26 includes internal splines 28 splined to teeth 30 on a series of separator plates 32. This rotationally fixes the separator plates 32 relative to the housing 26. The separator plates 32 are interleaved with a series of friction discs 34 to form a wet clutch assembly 36. The friction discs 34 have friction paper on each side and radially spiraling grooves 35 on both of their paper faces.
The friction discs 34 also have teeth 37 which are engaged to splines 38 on a ring shaped damper mass (damper ring) 40. This rotationally fixes the friction discs 34 relative to the damper mass 40. The damper mass 40 is elastically attached to a hub 42 through damper spring packs 44, made up of steel leaf springs. Alternate spring packs 44 are pre-stressed in opposite directions (clockwise and counterclockwise) so that even at maximum damper excitation the springs never become completely unloaded, eliminating the possibility for unsprung free-play. A bushing 43 separates the damper springs 44 from the housing 26. A damper plate 46 is rigidly attached to the hub 42 and is located adjacent to the face of the damper mass 40 to provide viscous friction to the damper mass 40.
The hub 42 of the speed limiting drive pulley assembly 16 includes a bore 48 which is splined to the conventional engine crankshaft 14 and held in place with a screw and washer/puller 45. When removal of the hub 42 from the crankshaft 14 is desired, a retaining ring 41 serves to transfer the pulling force from the washer/puller 45 to the hub 42. A rear oil seal 49 seals between the housing 26 and the hub 42, while allowing the two to rotate relative to each other.
The clutch assembly 36 basically allows torque to be transmitted from the hub 42 to the pulley member 24. The torque transmitting capability of the clutch assembly 36 is proportional to the load it receives which presses its members together.
A front cover 50 includes a series of radial grooves 52 on its inside surface. It also includes radially extending fins 53 on the outside surface. The front cover 50 mounts to the housing 26, and a front oil seal 51 seals between the cover 50 and the hub 42 while allowing the two to rotate relative to each other. An O-ring 47 seals between the cover 50 and housing 26.
A piston 54 is located adjacent to the clutch assembly 36 in a mating bore in the housing 26, with a belleville spring (disc spring) 56 mounted between the piston 54 and the housing 26 to bias the piston 54 toward the clutch assembly 36. The belleville spring 56 provides a spring force that is relatively constant over the range of the piston travel, which reduces sensitivity to assembly tolerances and clutch wear. As an option, the spring force of the belleville spring 56 can be selected to produce an increased force when the clutch pack wears and a glazing of the friction discs 34 causes a reduction of the coefficient of friction.
During assembly, the piston 54 is initially installed into the mating bore in the housing 26 with the enclosed volume between the piston 54 and the bottom of the bore entirely filled with a volatile liquid such as a solution of water and ethylene glycol. A retaining ring 58 is installed to keep the piston 54 inside the bore and the piston 54 is forced to the bottom of the bore to force most of the liquid out through an evacuation passage 60 in the housing 26. The back face of the piston 54 is configured so that when the piston 54 is forced to the bottom of the bore and the belleville spring 56 is pressed flat, the enclosed volume is very small. The evacuatic passage 60 is then permanently sealed with a plug 62 to retain the small remaining amount of the liquid inside the bore and to prevent the entry of any air. When the piston 54 is released, the belleville spring 56 pushes the piston 54 outward against the retaining ring 58. The enclosed volume now contains only a small amount of the liquid and the vapor from the liquid.
The front face of the piston 54 has radially oriented fins 64 to give good heat transfer from oil, discussed below, in front of the piston 54 to the liquid behind the piston 54. The fins 64 also force the oil to rotate with the piston 54 so that the hydraulic force acting on the piston 54 is a function of the housing rotational speed, and not of the hub speed. The first separator plate in the series includes a member 66 that engages with the radial fins 64 of the piston 54 to prevent the piston 54 from rotating relative to the housing 26.
During assembly, the internal spaces of the pulley housing 26 are filled with oil and sealed therein when the front cover 50 is attached, so oil surrounds the entire clutch assembly 36.
During engine operation, the speed limiting drive pulley assembly 16 is basically direct drive at low engine speeds, i.e., the pulley member 24 rotates at crankshaft speed with no slip between the two. The belleville spring 56 biases the piston 54 against the wet clutch assembly 36 with enough force to allow torque to be transmitted through the pulley assembly 16 from the hub 42 to the pulley member 24 with no slip.
As the housing 26 is rotated faster by the crankshaft 14, the centrifugal force on the oil will cause it to push outward. As it pushes outward, it also presses against the piston 54 in the opposite direction of the belleville spring force. This reduces the amount of force with which the piston 54 pushes against the clutch assembly 36. Thus, as the housing 26 speeds up more, the force of the piston continues to be reduced, and the torque transmitting capability of the clutch assembly 36 lessons. The friction discs 34 can then begin to slip relative to the separator plates 32.
The torque transmitted during slipping operation conditions is through shearing of the fluid (oil) between the separator plates 32 and friction discs 34, which minimizes wear of the friction elements. By selecting the appropriate size and shape of piston 54 and spring force for the belleville spring 56, the oil pressure can completely cancel the force of the belleville spring 56 and allow the slipping at the desired rotational speed.
With increasing speed, the torque transmitting capability of the clutch assembly 36 diminishes such that with minimal accessory load, the pulley member speed is limited to a particular maximum speed while the hub 42 (and crankshaft 14) may rotate considerably faster. Line 68 in FIG. 6 illustrates the speed limit.
During clutch slipping, heat is produced in the fluid being sheared at the clutch faces. The difference in rotational speed between the grooves 35 in the friction discs 34, which rotate faster than the housing 26 and fling oil outward; and grooves 52 in the front cover 50, which rotates slower than the crankshaft 14 and allows the oil to travel radially inward, creates a pressure differential that pumps the fluid in a loop out from the clutch assembly 36, in past the front cover 50 and back to the clutch assembly 36. Further, the fins 53 on the outside of the front cover 50 reject heat from the oil in the grooves 52 to the air around the engine.
It is expected that in most applications and for most typical engine operations, the engine 12 will spend very little time at high enough speeds to cause slipping in the clutch assembly 36 and the small amount of slipping that occurs will not produce a large amount of heat. In some applications, however, the engine 12 may operate at high speeds for extended periods of time. The resulting prolonged slipping in the clutch assembly 36 will release a significant amount of heat, which will raise the temperature of the speed limiting drive pulley assembly 16.
There is a high temperature compensating feature to limit the maximum temperature at which the clutch operates. With increasing temperature of the oil, and hence the piston 54, the water vapor pressure behind piston 54 (in the housing bore with the belleville spring) acts on the piston 54 against the pushing action of the oil. This puts additional clamping load on the clutch assembly 36, increasing the housing speed at which the clutch will begin slipping. Since water vapor pressure versus temperature is highly non-linear, very little change in pressure occurs between cold and normal operating temperature and thus does not significantly affect the force applied to the clutch assembly 36 by piston 54, yet a large increase in force occurs between normal to hot temperatures, due to an increase of the pressure behind the piston 54 and adding to the clamping load on the clutch assembly 36. This serves to account for engine operating conditions where the clutch assembly 36 is heating up too much due to operation at high crankshaft speed for an extended period of time. While the accessories are now driven at a faster upper speed limit, possibly increasing noise and wear, the possible damage to the speed limiting drive assembly due to overheating is minimized.
The graph in FIG. 6 illustrates higher maximum speed cutoffs 70 above the base cut off speed 68 for an alternator based upon the effect of the heat compensating mechanism.
A separate function that the speed limiting drive pulley assembly 16 performs is as a crankshaft damper. The damper mass 40, being elastically connected to the crankshaft 14 through the damper springs 44 acts in a manner similar to a conventional rubber mass mounted to a crankshaft. However, the damper springs 44 are made of steel rather than rubber to resist the strain caused by the higher amplitude of motion of the smaller inertia mass that is required to allow it to be packaged inside of the housing 26. With this arrangement, both the speed limiting and damper functions are performed using less space than with two separate assemblies.
A second embodiment is disclosed in FIGS. 7 and 8 where the piston and belleville spring of the first embodiment are replace with a sealed bellows arrangement. For purposes of this description, elements in this embodiment that have counterpart elements in the first embodiment have been identified by similar reference numerals, although given 100 series numbers.
The hub 142 still drives the pulley member 124 through a clutch assembly 136. In this case, however, the axial force applied to the clutch assembly 136 is provided by a sealed bellows 176. The bellows 176 is located between the front cover 150 and clutch assembly 136. The free length of the bellows 176 is longer than its installed length, so that in assembly, the elastic compression of the bellows' convolutions produces a spring force on the clutch assembly 136, enabling the clutch assembly 136 to transmit torque. Optionally, if needed, an additional spring, not shown, may augment the force. In this embodiment, damper plates 146 are located on both sides of the damper mass 140.
Oil in the housing 126 surrounds the bellows 176. Similar to the first embodiment, when the housing 126 rotates at high speed, centrifugal acceleration on the oil produces a pressure that acts to compress the bellows 176, reducing the clamping load on the clutch assembly 136 and allowing the clutch to slip.
Further, the interior of the bellows 176 is evacuated except for a small amount of fluid (such as water). This acts as a high temperature compensating feature as in the first embodiment. When the clutch 136 is slipping, heat is produced in the fluid being sheared at the clutch faces, as discussed above. As the oil passes from the clutch assembly 136 to the front cover 150 and back again, it flows around the bellows 176 and heats it to the oil temperature. If the temperature rises, the bellows 176, being evacuated of air, but containing the small amount of liquid, will try to expand due to an increase in vapor pressure. The bellows 176 will then press harder against the clutch assembly 136, reducing the slipping, and thus reducing the heat input to the system. At low and moderate temperatures, the torque transmitting capability is not significantly affected by changes of temperature, but as the temperature of the clutch 136 approaches damaging levels, the torque carrying capacity increases sufficiently to decrease the amount of slipping and resulting friction heat to minimize additional temperature increase.
FIG. 9 illustrates a third embodiment of the present invention, which is similar to the first embodiment except that the damping function of the damper mass and spring is not incorporated into the speed limiting assembly. For purposes of this description, elements in this embodiment that have counterpart elements in the first embodiment have been identified by similar reference numerals, although given 200 series numbers.
The damper mass and damper springs are replaced with a single ring member 240 that rotationally couples the hub 242 directly to the friction discs 234 without the elasticity of damper springs. In this case, there will be no torsional damping effect for the crankshaft, but the speed limiting effect of the clutch assembly 236 will still operate to protect the engine accessories and the high temperature compensating feature will limit the temperature in the housing. Although, the combination of the damper assembly with the overall speed limiting drive pulley eliminates the need for a separate conventional rubber crankshaft mounted damper, making the assembly that performs the two functions more compact. Further, the ring member 240 and the hub 242 can also be formed as one integral part, if so desired.
While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims. | A speed limiting accessory drive for use with an engine in a vehicle. A speed limiting drive pulley (16) is affixed to a crankshaft (14) via a hub (42) and includes a pulley member (24) which drives the accessory belt (18). A Clutch assembly (36) is operatively located between the hub and pulley member, with a piston (54) or bellows biased against and engaging the clutch assembly. Oil located throughout the clutch assembly is acted on by centrifugal force when the drive pulley is rotating and acts to push against the biases of the piston. This allows the clutch to slip at high engine speeds, thus limiting the speed of the pulley member. A heat compensating mechanism acts to counter the pushing force of the oil if the temperature of the oil rises too high due to the clutch slippage, thereby reducing clutch slip. | 5 |
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application Ser. No. 11/302,951 (Attorney Docket No. 021872-002200US) filed Dec. 13, 2005, the full disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to devices and methods for percutaneous sealing of puncture sites in body lumens or tissue tracts. More specifically, the present invention relates to drug eluting vascular closure devices and methods for hemostasis of vascular puncture sites.
[0004] Percutaneous access of blood vessels in the human body is routinely performed for diagnostics or interventional procedures such as coronary and peripheral angiography, angioplasty, atherectomies, placement of vascular stents, coronary retroperfusion and retroinfusion, cerebral angiograms, treatment of strokes, cerebral aneurysms, and the like. Patients undergoing these procedures are often treated with anti-coagulants such as heparin, thrombolytics, and the like, which make the closure and hemostasis process of the puncture site in the vessel wall at the completion of such interventional procedures more difficult to achieve.
[0005] Various devices have been introduced to provide hemostasis, however none have been entirely successful. Some devices utilize collagen or other biological plugs to seal the puncture site. Alternatively, sutures and/or staples have also been applied to close the puncture site. External foreign objects such as plugs, sutures, or staples however may cause tissue reaction, inflammation, and/or infection as they all “leave something behind” to achieve hemostasis.
[0006] There is also another class of devices that use the body's own natural mechanism to achieve hemostasis wherein no foreign objects are left behind. Such devices typically provide hemostasis by sealing the puncture site from the inside of the vessel wall wherein the device is left in place in the vessel lumen until hemostasis is reached and thereafter removed. Although such safe and simple devices have achieved relative levels of success, they often are slow in achieving complete hemostasis, particularly in highly anti-coagulated patients. As such, such devices are often used as an adjunct to manual compression which still remains to be the most used method in closing the puncture site after the interventional procedure.
[0007] There is yet another class of devices where highly thrombogenic substances are mixed and injected to the puncture site for the purpose of accelerating the hemostatic process. These mixtures contain one or more clot promoting substances, such as thrombin and/or fibrinogen, along with other substances, such as collagen. These devices generally work by first occluding the puncture site from the inside of the vessel, usually by use of a balloon, and then injecting the mixture into the tissue tract. The balloon is then removed. Such devices suffer from several drawbacks which may cause severe complications. For example, the occluding member may not be adequate to prevent these highly thrombogenic substances from entering the blood vessel. Further, the injection of the mixture is often not well controlled and highly technique dependant, which again may allow these substances to enter the blood stream.
[0008] In light of the above, it would be desirable to provide alternative devices and methods for providing complete hemostasis of a puncture site in a body lumen, particularly blood vessels of the human body. It would be particularly desirable if such devices and methods utilize the body's own natural healing mechanism to achieve hemostasis. It would be further desirable if the natural hemostatic process can be safely accelerated by the controlled use of bio-chemical agents. It would be further desirable if such devices and systems utilize a simple construction and user interface allowing for convenient application without numerous intermediary steps. Further, such devices should be safe and reliable without the need for much user intervention. At least some of these objective will be met by the devices and methods of the present invention described hereinafter.
[0009] 2. Description of the Background Art
[0010] Hemostasis devices for use in blood vessels and tracts in the body are described in pending U.S. patent application Ser. Nos. 10/974,008; 10/857,177; 10/821,633; 10/795,019; and 10/718,504 and U.S. Pat. Nos. 6,656,207; 6,464,712; 6,056,770; 6,056,769; 6,045,570; 6,022,361; 5,951,589; 5,922,009; and 5,782,860, assigned to the assignee of the present application. The following U.S. Patents and Publications may be relevant to the present invention: U.S. Pat. Nos. 4,744,364; 4,852,568; 4,890,612; 5,108,421; 5,171,259; 5,258,000; 5,383,896; 5,419,765; 5,454,833; 5,626,601; 5,630,833; 5,634,936; 5,728,134; 5,836,913; 5,861,003; 5,868,778; 5,951,583; 5,957,952; 6,017,359; 6,048,358; and 6,296,657; U.S. Publication Nos. 2002/0133123; 2003/0055454; 2003/0045835; and 2004/0243052.
[0011] The full disclosures of each of the above mentioned references are incorporated herein by reference.
BRIEF SUMMARY OF THE INVENTION
[0012] The present invention provides drug eluting, self-tensioning closure devices and methods for percutaneous access and closure of puncture sites in a body lumen, particularly blood vessels of the human body. It will be appreciated however that application of the present invention is not limited to the blood vasculature, and as such may be applied to any of the vessels, even severely tortuous vessels, ducts, and cavities found in the body as well as tissue tracts. Such closure devices and methods utilize the body's own natural healing mechanism to achieve hemostasis. This natural hemostatic process is further accelerated by the integration of bio-chemical agents or means for delivering such agents.
[0013] In a first aspect of this invention, a device for closing a blood vessel puncture site disposed at a distal end of a tissue tract comprises a shaft having a proximal end and a distal end, an expansible member, a bio-chemical sealing member, and a bio-chemical region or release region. The shaft is configured to advance through the tissue tract while the expansible member disposed on the distal end of the shaft is deployable within the blood vessel. The bio-chemical sealing member is slidably disposed over the shaft and proximal the expansible member. The bio-chemical region or release region is disposed under the sealing member. Advantageously, displacement of the bio-chemical sealing member in a proximal direction exposes the region so as to allow for safe and controlled release of bio-chemical agents into the tissue tract for enhanced and complete hemostasis of the puncture site.
[0014] The bio-chemical sealing member prevents severe complications as a result of bio-chemical agents from coming in contact with the blood stream by only allowing for the controlled exposure of such agents in the tissue tract. The sealing member has a length in a range from about 0.1 cm to about 100 cm, typically from about 5 cm to about 20 cm and a diameter in a range from about 0.5 mm to about 5 mm, typically from about 1 mm to about 3 mm. The sealing member may be a tubular member formed from a variety of medical grade materials, including coiled stainless steel tubing or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like.
[0015] In a preferred embodiment of the device, a tensioning element, such as a spring or coil, is further provided. The tensioning element is slidably disposed over the shaft and under the sealing member proximal the expansible member. Generally, during application of the device, the tensioning element is preferably positionable in the tissue tract, but in other instances may be outside the tissue tract. The tensioning element gauges how much tension is being applied to the expansible member as it is seated against the puncture site so as to prevent a user from applying excessive force on the device causing undesirable movement (e.g., device is pulled out of patient body). The tensioning element also provides device compliance in cases of patient movement while the device is in place. The expansible member allows for sealing of the puncture site while the tensioning element along with an external clip apply and maintain tension to the expansible occluder so that it is seated against the puncture site at a vascular surface (e.g., blood vessel wall).
[0016] Positioning the expansible member against the vessel wall positions the bio-chemical region or release region outside the vessel lumen at a predetermined distance from the vessel wall and proximal the expansible member. Therefore, the expansible member provides not only occlusion at the vessel puncture site but also functions as a locator so as to position the bio-chemical region or release region outside the vessel lumen. This in turn ensures safe release of bio-chemical agents in the tissue tract and outside the blood stream. The predetermined distance is in a range from about 0 to about 20 mm, typically in a range from about 2 mm to about 10 MM.
[0017] The bio-chemical region or release region has a length in a range from about 1 mm to about 100 mm, typically in a range from about 5 mm to about 50 mm. It will be appreciated that the length and/or volume of the region may be varied in order to integrate and release the desired amount of bio-chemical agent. In one embodiment, the bio-chemical region includes at least one bio-chemical agent disposed on the distal end of the shaft proximal the expansible member and distal the tensioning element. In another embodiment, the region includes at least one bio-chemical agent disposed on the tensioning element. The agents may be coated, sprayed, molded, dipped, vapor deposited, plasma deposited, or painted thereon. Such a bio-chemical region on the occlusion device itself further minimizes variations due to user techniques, which may be particularly problematic with injection protocols where such agents are injected into the tract by the user. In yet another embodiment, the device may further incorporate an expansible feature disposed on the distal end of the shaft proximal the expansible member, wherein the region includes at least one bio-chemical agent associated with the expansible feature.
[0018] In alternative embodiments of the present invention, the device may further incorporate at least one bio-chemical delivery conduit disposed over the shaft and under the tensioning element and a bio-chemical injection port in fluid communication with the delivery conduit. The injection port may be connected to a syringe by use of a compression fitting or with an integrated luer lock. The bio-chemical agents are injected into the device via the syringe once the device is properly positioned. It will be appreciated that the size of the injection port and the delivery conduit may be selected to control the delivery rate of such agents. In one example, the release region includes at least one opening, aperture, or orifice in fluid communication with a distal end of the conduit proximal the expansible member. It will be appreciated that any number, size, and/or shape of opening(s) may be utilized in order to obtain the desired release rate of bio-chemical agent. The release region may incorporate about 1 opening to about 100 openings, typically about 1 opening to about 10 openings. In another example, the release region includes at least one porous member in fluid communication with a distal end of the conduit proximal the expansible member so as to allow for the desired release of the bio-chemical agent.
[0019] A controlled delivery rate allows the bio-chemical agents to “ooze” out of the release region. This may eliminate the potential of high pressure release, which in turn minimizes the possibility of these agents from entering the blood stream. In addition, the sealing member serves to cover the bio-chemical release region so as to prevent any blood from flowing back through the release region, through the delivery conduit, and out through the injection port. The sealing member is only slidably displaced, revealing the bio-chemical release region, when it is desirable to deliver the bio-chemical agents.
[0020] The device of the present invention may further incorporate a spacer element disposed between the sealing member and the tensioning element so that the sealing member may easily slide over the tensioning element. The spacer element may be a tubular member formed from a variety of materials, including tubular polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. The device further includes a handle on a proximal end of the shaft. A safety tab may be disposed between the handle and the sealing member. The safety tab prevents any undesirable displacement of the sealing member so as to inhibit inadvertent release of bio-chemical agents.
[0021] The present invention integrates the expansible member, bio-chemical sealing member, bio-chemical region or release region, and tensioning element in a single unitary catheter construction. This simple construction and user interface allows for safe, easy and convenient application of the device without numerous intermediary steps. The sealing member in combination with the locating expansible member ensures that the bio-chemical region or release region is only exposed in the tissue tract. This results in a more reliable, safe, and effective device which provides immediate and complete hemostasis, which in turn reduces the risk of bleeding, hematoma formation, thrombosis, embolization, and/or infection.
[0022] In another aspect of the present invention, methods for hemostasis of a puncture site in a blood vessel at a distal end of a tissue tract are provided. One method comprises introducing any one of the closure devices as described herein through the tissue tract. The expansible member is deployed at a distal end of the device within the blood vessel. The bio-chemical sealing member disposed proximal the expansible member is then displaced once properly positioned so as to expose a bio-chemical region or release region of the device. At least one bio-chemical agent is then released from the device and into the tissue tract.
[0023] The sealing member is displaced in a proximal direction so as to expose at least a portion of the region. This displacement distance is in a range from about 0.1 cm to about 10 cm, typically from about 0.5 cm to about 5 cm. The method further comprises deploying the tensioning element disposed proximal the expansible member within the tissue tract so that the expansible member is seated against a puncture site. Typically, deploying the tensioning element and displacing the sealing member is carried out simultaneously so as to provide for easy and convenient application of the device without numerous intermediary steps. However, it will be appreciated that deployment of the tensioning element may be carried out independently, typically prior to displacement of the sealing member, so as to provide for proper positioning of the region or release region within the tissue tract and closure of the puncture site.
[0024] The amount of tension applied to the expansible member by the tensioning coil or spring is in the range from about 0.5 ounce to 30 ounces, typically in a range from about 2 ounces to 10 ounces. As described above, the expansible member locates and closes the puncture site in the blood vessel wall. Coil elongation is sufficient to provide adequate amount of tension on the expansible member to temporary seal the puncture and to adequately displace the sealing member to reveal the bio-chemical region or release region. In some embodiments, coil elongation may be limited by a coupling member. Generally the amount of elongation of the tensioning coil may be the same as for displacement of the sealing member. The tension provided by the tensioning coil and the exposure of the bio-chemical agents may be maintained by application of an external clip on the tensioning coil, generally over the sealing member, wherein the clip rests over the skin at the puncture site.
[0025] Bio-chemical agent release generally comprises positioning the region at a predetermined distance proximal to the expansible member and outside the blood vessel wall. In particular, increasing the tension in the coil positions the expansible member against the puncture site and locates the bio-chemical region or release region in the tissue tract at the predetermined distance. Further increase in tension will cause the sealing member to disengage from an attachment point at the proximal end of the expansible member and the tensioning coil to elongate. Elongation of the tensioning coil will result in the sealing member to slide proximally so as to expose the region to the surrounding tissue for release of the bio-chemical agent.
[0026] The bio-chemical agents may accelerate the coagulation process and promote the formation of coagulum at the puncture site so to achieve complete hemostasis. The bio-chemical agent may comprise a variety of agents including clot promoting agents (e.g., thrombin, fibrinogen, etc.) or vaso-constricting agents (e.g., epinephrine, etc.). The bio-chemical agent is released for a time period in the range from about 0.1 minute to about 15 minutes, typically from about 0.5 minute to about 5 minutes. As described above, the occlusion device may be modified in several ways (e.g., region length, region volume, release region openings, conduit dimensions, number of conduits, or port dimensions) to achieve the desired bio-chemical agent release characteristics (e.g., rate, amount, time, etc.). The methods of the present invention may involve re-hydrating the bio-chemical agent with fluid in the tissue tract so as to generate coagulum. These agents may use the blood components to form a coagulum even at the presence of anti-coagulants.
[0027] As described above, the bio-chemical agent may be coated, sprayed, molded, painted, dipped, or deposited at the region. Alternatively, bio-chemical agents may be injected in a delivery conduit in fluid communication with at least one opening disposed at the release region. The sealing member in such an embodiment further prevents any blood from flowing back through the openings of the release region prior to placing the expansible member against the vessel wall when the release region is in the vessel lumen. Injection of bio-chemical agents in the presence of blood in the bio-chemical delivery pathway may cause undesirable coagulum to form in the pathway which could prevent the bio-chemical agents from reaching the target site.
[0028] A further understanding of the nature and advantages of the present invention will become apparent by reference to the remaining portions of the specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The following drawings should be read with reference to the detailed description. Like numbers in different drawings refer to like elements. The drawings, which are not necessarily to scale, illustratively depict embodiments of the present invention and are not intended to limit the scope of the invention.
[0030] FIG. 1 illustrates a first embodiment of a drug eluting, self-tensioning vascular closure device for hemostasis of vascular puncture sites constructed in accordance with the principles of the present invention.
[0031] FIG. 2 illustrates an exploded view of the bio-chemical region on the distal end of the device of FIG. 1 .
[0032] FIG. 3 illustrates the device of FIG. 1 in an expanded configuration with the occluding member deployed.
[0033] FIG. 4 illustrates the device of FIG. 1 in an expanded configuration with the occluding member under tension after removal of the safety seal and with the bio-chemical sealing member displaced proximally so as to expose the contents of the bio-chemical region.
[0034] FIGS. 5A through 5F illustrate a method for hemostasis of a puncture site in a body lumen employing the device of FIG. 1 .
[0035] FIG. 6 illustrates a second embodiment of a drug eluting, self-tensioning vascular closure device for hemostasis of vascular puncture sites constructed in accordance with the principles of the present invention.
[0036] FIG. 7 illustrates an exploded view of the bio-chemical injection port and delivery conduit of the device of FIG. 6 .
[0037] FIG. 8 illustrates an exploded view of the bio-chemical release region on the distal end of the device of FIG. 6 .
[0038] FIG. 9 illustrates the device of FIG. 6 in an expanded configuration with the occluding member deployed.
[0039] FIG. 10 illustrates the device of FIG. 6 in an expanded configuration with the occluding member under tension and with the bio-chemical sealing member displaced proximally so as to expose the bio-chemical release region so that attachment of a syringe to the bio-chemical injection port provides delivery of bio-chemical agents.
DETAILED DESCRIPTION OF THE INVENTION
[0040] Referring now to FIG. 1 , a first embodiment of a drug eluting, self-tensioning vascular occlusion device 70 for hemostasis of vascular puncture sites is illustrated, wherein at least one bio-chemical agent 152 is integrated with the device in a bio-chemical region or chamber 151 . Device 70 generally comprises a first flexible elongated tubular member 71 formed from coiled stainless steel tubing or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. Tubular member 71 may have a length in a range from about 5 cm to about 50 cm, typically in the range from about 10 cm to about 30 cm and a diameter in the range from about 0.25 mm to about 5 mm, typically in the range from about 0.5 mm to about 2 mm. An expansible occlusion member 74 is disposed on the distal end of tubular member 71 . A bio-chemical sealing member 153 is slidably disposed over the tubular member 71 and proximal the expansible member 74 . The bio-chemical region 151 containing the bio-chemical agent 152 is disposed under the sealing member 153 . It will be appreciated that the above depictions are for illustrative purposes only and do not necessarily reflect the actual shape, size, or dimensions of the device 70 . This applies to all depictions hereinafter.
[0041] The expansible member 74 may be formed from a variety of medical grade materials, including stainless steel, superelastic material such as NITINOL®, or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. Preferably the expansible member 74 is made of superelastic NITINOL® material. The expansible member 74 in a retracted or collapsed state has a diameter of less than about 3 mm, preferably less than about 1.5 mm, as shown in FIGS. 1 and 2 . When deployed, the expansible member 74 in an expanded state has a diameter in a range from about 3 mm to about 20 mm, preferably from about 3.5 mm to about 8 mm, as shown in FIGS. 3 and 4 . Exemplary expansible structures 74 are described in detail in co-pending U.S. patent application Ser. No. 10/718,504. Still further embodiments of a braided mesh member 74 are described in U.S. Pat. No. 5,836,913.
[0042] The expansible member 74 may at least partially or preferably be fully covered with an elastomeric membrane material 96 . Membrane 96 may be formed from a variety of medical grade materials, such as thermoplastic elastomers (e.g., CHRONOPRENE® or POLYBLEND®) having durometers in a range from 15 Å to about 40 Å. Membrane 96 may be connected at a distal connection point 77 and a proximal connection point 75 . Adhesives such as LOCTITE® 4014 may be used to attach membrane 96 to the expansible member 74 and catheter shaft 71 . Alternatively, membrane 96 may take a form of a sock having its distal end sealed through a heat stake process or the like. In this case membrane 96 may not have to be attached distally. Membrane 96 preferably has a diameter that is sufficient to cover the expansible member 74 . In some embodiments, membrane 96 may be designed and attached to facilitate expansible member deployment as well as to reduce the amount of required elongation when the expansible member 74 is deployed. This may be achieved by molding the membrane 96 so that its midpoint diameter, where deployed expansible member 74 has its greatest diameter, is larger than its proximal and distal end diameters (e.g., a spherical shape). Membrane 96 may also be formed like a tube with a larger diameter than needed (e.g., diameter of retracted expansible member 74 ), and then stretched over expansible member 74 and attached. The stretch should be enough to reduce the diameter of the membrane 96 to that of the expansible member 74 . In such a case, when member 74 is deployed, there is less elongation and stress experienced by membrane 96 . The membrane 96 may additionally form a membrane tip at a distal end of catheter 70 so as to provide a soft and blunt point for percutaneous access.
[0043] Referring now to FIG. 2 , the bio-chemical agents 152 may be composed of clot promoting agents such as thrombin and fibrinogen and/or vaso-constrictors such as epinephrine. These agents 152 may take on a form of a powder, paste that can be applied to the bio-chemical chamber or region 151 . Alternatively, such agents 152 may be molded in a form of a cylindrical tube with a longitudinal central hole that can be slidably disposed over member 71 and positioned between fixed attachment members 75 and 150 in the assembly process. The bio-chemical chamber/region 151 is located between the proximal end of member 75 and distal end of attachment member 150 . The length of region 151 determines the amount of bio-chemical agents 152 that can be integrated with the device, as well as the extent of the exposure of such agents to the tissue. It should also be noted that by increasing the outside diameters of members 75 and 150 , the volume of chamber 151 can be increased and hence the volume of the bio-chemical agents 152 incorporated with the device.
[0044] The bio-chemical sealing member 153 generally comprises a flexible elongated tubular member. In a preferred embodiment, the tubular member 153 may have a length that extends from attachment member 75 , and overlapping member 75 , to grip member 85 , partially or fully overlapping member 85 . The inside diameter of member 153 , at least at the distal end, is similar to the outside diameter of member 75 . Member 153 is slidably positioned, at least partially, over member 75 . The interaction of members 153 and 75 provide for a fluid tight barrier so that blood will not come in contact with the bio-chemical agent prior to the intended time.
[0045] In the preferred embodiment of the present invention, a tensioning element 86 is slidably disposed over the tubular member 71 and proximal the expansible member 74 . the tensioning coil 86 is attached to the tubular member 71 with attachment member 150 . Member 150 may be in a tubular form and made from stainless steel tubing or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. Coil 86 , attachment member 150 and tubular member 71 are connected together by use of epoxy. The attachment point may be from 1 mm to 100 mm proximal to the member 75 , preferably in the range of 5 mm to 50 mm. The tensioning element 86 is described in more detail in co-pending U.S. patent application Ser. No. 10/974,008.
[0046] The function of bio-chemical seal 153 is to provide a barrier between the bio-chemical agents 152 and bodily fluids such as blood, and only allow the exposure of such agents to the tissue when the device is in correct position and the operator chooses to do so. Exposure of the bio-chemical region 151 to the surrounding tissue happens when the tensioning coil 86 is grabbed at grip member 85 and is pulled proximally with respect to member 75 to apply tension to the deployed expansible member 74 at the puncture site. The proximal pull of grip member 85 causes the tensioning coil 86 to elongate. The seal member 153 is attached to the coil 86 and grip member 85 . Since member 153 is not stretchable, the elongation of coil 86 results in disengagement of the distal end of member 153 from member 75 . Seal 153 slides proximally over the bio-chemical chamber/region 151 and exposes the bio-chemical agents 152 to the surrounding tissue. A spacer 154 provides adequate space between coil 86 and sealing member 153 , so that member 153 can easily slide over coil 86 . It should be noted that coil 86 elongation happens as the result of interference of the occluding expansible member 74 with the vessel wall at the puncture site. This in turn slides the sealing member 153 proximally, exposing the bio-chemical agents 152 in the tissue tract where it is needed.
[0047] It will be appreciated that bio-chemical seal 153 may be constructed to function independently from the tensioning coil 86 . Also, in some embodiments, a length of coil 86 , or the entire length of coil 86 may be coated with the bio-chemical agent 152 . In such case, when coil spring 86 is elongated to provide tension to the expansible member 74 , the deformation of the elongating coil spring 86 may result in breaking off of the agents 152 from the coil. This may result in faster re-hydration of the bio-chemical agents 152 and consequently acceleration of the coagulation process in the tract. Still further, the bio-chemical chamber 151 of device 70 may include an expansible feature over which the bio-chemical agent 152 is dispensed (e.g., coated). When desirable, this expansible member which may take the form of a balloon or a braided mesh, can be expanded, resulting in the agents 152 breaking off in the surrounding tissue, and hence accelerating the bio-chemical reaction.
[0048] The device 70 of the present invention may further incorporate a safety seal 155 to prevent inadvertent release of bio-chemical agents 152 by preventing coil 86 from sliding over member 71 . Safety seal 155 may be made of different materials and be implemented in different fashions. One such implementation may take the form of heat shrinkable tubing. The tubing may be shrunk over member 71 to the proximal end of the coil 86 or preferably overlapping grip member 85 . To remove the safety seal with ease, seal 155 may have a tab 156 that may be easily grabbed and pulled, tearing the safety seal 155 along the length of member 71 . Removal of the safety seal 155 would allow coil 86 to freely slide over tubular member 71 , exposing the bio-chemical agents 152 to the surrounding tissue.
[0049] The bio-chemical agent 152 is sealed from coming in contact with the circulating blood and generally is released in the tissue tract in the fascia at the puncture site. During device application, the expansible member 74 will be positioned and anchored against the puncture site in the vessel lumen. In particular, the expansible member 74 allows for sealing of the puncture site and locating the bio-chemical agents 152 appropriately in the tissue tract. The tensioning element 86 applies and maintains tension to the expansible occluder 74 while the sealing member 153 simultaneously reveals the bio-chemical agents 152 to bring such agents in contact with the surrounding tissue to accelerate the process of hemostasis.
[0050] Referring now to FIGS. 3 and 4 , a proximal end of the device 70 comprises deployment means 78 . Deployment of the expansible member 74 typically comprises pushing or pulling the two part handle assembly 78 coupled to the expansible member 74 . A proximal end of handle assembly 78 comprises an actuating assembly 101 which is coupled to a push/pull member 76 . Proximal movement of assembly 101 relative to a grip handle 102 deploys the expansible member 74 . The grip handle 102 comprises a tubular member 103 formed from suitable metal tubing (e.g., stainless steel) or polymer materials (e.g., polyurethane, polyimide, PEEK®, PEBAX®, and the like). Member 103 is coupled to the catheter shaft 71 by means of an expander element 104 so as to account for the difference in an outside diameter of catheter 71 and an inside diameter of member 103 . Elements 71 , 103 , and 104 may be attached by the use of adhesives. Member 103 further includes a feature 105 , such as an indentation from a crimping process when element 103 is formed from a stainless steel or other metallic hypotube. Indentation 105 provides interference to element 106 of the actuating assembly 101 .
[0051] Actuating assembly 101 further includes a tubular member 107 that is attached to the push/pull member 76 by a crimp process and/or adhesive. Member 107 provides added stiffness to the actuating mechanism 101 as well as provides for a larger surface area that consequently allows for enhanced adhesion of elements 106 , 108 , and 109 to member 107 . These elements may comprise individual, separate parts, preferably formed from polymer materials such as polyurethane, polyimide, PEEK®, PEBAX®, and the like. These elements may be optionally incorporated into element 107 through an over molding process. Once the device 70 is deployed, interference of detent element 106 with indentation 105 securely maintains the expansible member 74 in its deployed position as shown in FIGS. 3 and 4 . A proximal end of detent 106 may have a shallow angle in relation to the catheter shaft 71 so as to provide simplified deployment of the expansible member 74 . A distal end of detent 106 may be more perpendicular to the catheter shaft 71 so as to provide more interference to feature 105 , thereby requiring greater force to undeploy the expansible member 74 . The increased undeployment force is desirable to avoid inadvertent device collapse. Optionally, indentation 105 may be designed so that a distal side of the feature has a much shallower angle in relation to the catheter shaft 71 than a proximal side.
[0052] Elements 108 and 109 primarily provide support and alignment of the actuating assembly 101 . Element 109 may be formed from a bright distinct color to indicate when the expansible member 74 is deployed. Element 110 comprises a tubular member, preferably having the same outer diameter as member 103 . A distal end of tubular member 110 abuts a proximal end of member 103 so as to provide a positive stop to the movement of the actuating assembly 101 during the undeployment of the expansible member 74 . Cap 111 at the most proximal end of the device 70 provides a soft tip for easier undeployment of expansible member 74 . Cap 111 may be formed from rubber or similar materials.
[0053] In operation, handle assembly 78 is held by grabbing onto element 103 with one hand and element 110 with the other hand. Element 110 is then pulled in a proximal direction while holding element 103 stationary. As element 110 is pulled back, detent 106 slides over indentation 105 until it is completely moved to the proximal side of feature 105 . FIGS. 3 and 4 illustrate the expansible member 74 that is in the form of a tubular braided mesh in the deployed and expanded state. The interference between elements 105 and 106 keeps the expansible member 74 in the deployed configuration. Undeployment of the device 70 may be effected with a single hand. In particular, member 103 may be grabbed by the palm of the hand while the thumb presses on cap 111 . This causes the actuating mechanism 101 to move forward and the detent member 106 to slide distally over feature 105 resulting in the retraction of the expansible member 74 .
[0054] Referring now to FIGS. 5A through 5F , a method for hemostasis of a puncture site in a body lumen employing the device 70 of FIG. 1 is illustrated. FIG. 5A depicts an existing introducer sheath 40 advanced through an opening in a skin surface 46 , tissue tract in fascia 45 and vessel wall 43 and seated in a vessel lumen 41 at the completion of a catheterization procedure. Device 70 is then inserted through the hub of the sheath 40 and is advanced until the expansible member 74 is outside the sheath 40 and in the vessel lumen 41 , as shown in FIG. 5B . This positioning may be indicated by a mark or feature on the catheter 71 or the handle assembly 78 .
[0055] As shown in FIG. 5C , the expansible member 74 is then deployed by operation of the handle assembly 78 . The sheath 40 is then slowly pulled out of the body, placing the expansible member 74 against the inner wall of the vessel 43 at the puncture site 42 . As the sheath 40 is removed, the grip member 85 which is slidably disposed over the catheter shaft 71 and the handle assembly 78 are revealed. Sheath 40 is then discarded, leaving deployed expansible member 74 seated at the puncture site 42 and the bio-chemical chamber/region 151 in the tissue tract 47 as shown in FIG. 5D . If the device is equipped with the safety seal 155 as in device 70 , then the safety seal 155 is removed by pulling the tab 156 proximally along the catheter shaft.
[0056] Referring now to FIG. 5E , once safety seal 155 is removed, the grip element 85 is grabbed and pulled in a proximal direction. Grip 85 is moved proximally to provide adequate amount of tension to the deployed expansible member 74 to achieve hemostasis. Typically, the amount of tension applied to the expansible member 74 is in the range of 0.5 ounces to 30 ounces. In particular, proximal movement of grip 85 causes simultaneous elongation of the tensioning coil 86 , causing the expansible member to locate and close the puncture site 42 , and displacement of the bio-chemical seal 153 , exposing the bio-chemical agent 152 to the surrounding tissue at a predetermined distance from the puncture site. The elongated position of coil 86 is maintained by application of a small external clip 50 to the catheter and seated against the surface of the skin 46 , as shown in FIG. 5E . Device 70 is left in this position for a period of time to allow the bio-chemical agent 152 to reconstitute with the fluids in the tissue tract 47 , generating coagulum. Clip 50 is then removed and the expansible member 74 is collapsed by manipulation of the handle assembly 78 . Device 70 is then removed, leaving the active bio-chemical agents 152 and the coagulum in the tract 47 and adjacent the vessel puncture site 42 , as shown in FIG. 5F . Additional finger pressure at the puncture site may be required to allow the coagulum to seal the small hole left in the vessel wall after removal of the device.
[0057] Referring now to FIG. 6 , another embodiment of an exemplary drug eluting, self-tensioning vascular occlusion device 80 for hemostasis of vascular puncture sites is illustrated, wherein the bio-active agents 152 may be stored separately and safely injected into the target site through a bio-chemical release region 163 once the device is properly positioned. The bio-chemical delivery system of device 80 is composed of an elongated tubular member 160 . Member 160 may be coaxially located over member 71 as shown in FIG. 6. 160 has an inside diameter that is larger than the outside diameter of member 71 . Member 160 is formed from coiled stainless steel tubing or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. The gap made between the inside of member 160 and the outside of member 71 defines the bio-chemical delivery conduit 161 .
[0058] Referring now to FIG. 8 , the distal end of member 160 has a plurality of openings 162 defining the bio-chemical release region 163 . Openings 162 vary in number and may be from 1 opening to 100 opening, preferably from 1 opening to 10 openings. The size, shape, and/or number of openings 162 determines the rate of the release of the bio-chemical agents into the surrounding tissues. Alternatively, the bio-chemical release region 163 may not be part of member 160 , and may be a separate member, made of porous material which is in fluid communication with member 160 . In either embodiment, release region 163 is located at a predetermined distance proximal to the expansible member 74 .
[0059] Referring now to FIG. 7 , a bio-chemical injection port 164 is illustrated. Port 164 comprises a flexible elongated tubular member that transitions to member 160 at its distal end by means of a coupling member 165 . At a proximal end, the port 164 provides a coupling to a syringe 167 for the injection of bio-chemical agents 152 . Members 164 and 165 may be constructed from stainless steel tubing or polymer materials such as nylon, polyurethane, polyimide, PEEK®, PEBAX®, and the like. Member 165 may or may not be a flexible member. Member 165 preferably has an outside diameter that is not larger than the outside diameter of the handle assembly 78 . This ensures that device 80 can go through the existing sheath 40 without interference, as was described for device 70 in FIGS. 5A through 5F . Coupling member 165 is connected to member 160 via member 166 . Members 164 , 165 and 160 are attached by means of epoxy to provide a fluid tight seal at attachment points 166 .
[0060] It will be appreciated that the drug delivery conduit 160 may comprise a single or multiple elongated tubular member(s) of varying length(s) that run(s) along the length of member 71 . At a proximal end, these conduits couple into delivery port 164 via coupling member 165 . At a distal end, these tubular members may terminate at different points proximal to the expansible member 74 , dispersed over release region 163 . Distally, these conduits may have at least one opening for the release of the bio-chemical agents into the region.
[0061] The bio-chemical sealing member 153 of device 80 functions in a similar fashion as in device 70 . In addition, the sealing member 153 of device 80 prevents blood from flowing back through the bio-chemical deliver path 163 , 162 , 161 , 164 . However, it will be appreciated that the back flow of blood through the bio-chemical delivery pathway may be used as an indicator that the bio-chemical release region 163 is in the vessel lumen. When the back flow stops, that may be an indication that the release region 163 is in the tissue tract, where there is no appreciable blood pressure. In addition to the expansible member 74 , this feature may add more certainty to the positioning of the bio-chemical release region 163 and hence improve safety. In such case, prior to injection of the bio-chemical agents 152 , the pathway may be flushed with solutions such as saline.
[0062] The tensioning coil 86 , spacer element 154 , and grip member 85 of device 80 function in a similar fashion as in device 70 . In device 80 , however, the elongation of tensioning coil 86 is limited by the distal end of coupling member 165 at attachment point 166 . The distance between the proximal end of the coil spring 86 and the distal end of coupling member 165 at point 166 is long enough to provide the adequate amount of tension. This distance is also sufficient to allow the bio-chemical seal 153 to move proximally to expose the entire bio-chemical release region 163 . FIG. 9 illustrates device 80 with a deployed expansible member 74 . FIG. 10 illustrates device 80 when the coil 86 is elongated to apply adequate amount of tension to expansible member 74 and to expose the bio-chemical release region 163 . The attachment of syringe 167 to delivery port 164 for delivery of bio-chemical agents 152 to the target site is also illustrated.
[0063] In operation, device 80 is inserted through the sheath 40 and advanced until the expansible member 74 is out of the sheath 40 and in the blood vessel 41 . The expansible member 74 is deployed by manipulation of the handle assembly 78 , the sheath 40 is removed and discarded, and the deployed expansible member 74 is placed against the inside wall of the vessel at the puncture site 42 . Tension is then applied by proximally sliding grip member 85 of coil 86 . The applied tension at the deployed expansible member 74 will provide hemostasis, and locates bio-chemical release region 163 . Elongation of the coil 86 reveals the bio-chemical release region 163 to the surrounding tissue tract 47 . The tension and coil elongation are maintained by application of an external clip 50 . Syringe 167 containing the bio-chemical agents 152 is then connected to the bio-chemical injection port 164 . An adequate amount of the agent(s) is injected into the site at tissue tract 47 . The bio-chemical agents 152 promote and accelerate the hemostatic process. After injection of the bio-chemical agents 152 , enough time is given for the agents to react with the blood tissue to form coagulum. External clip 50 is then removed, expansible member 74 is collapsed, and device 80 is removed. Removal of the device 80 may be followed by a few minutes of manual compression at the site to close the small hole left in the vessel wall.
[0064] Although certain exemplary embodiments and methods have been described in some detail, for clarity of understanding and by way of example, it will be apparent from the foregoing disclosure to those skilled in the art that variations, modifications, changes, and adaptations of such embodiments and methods may be made without departing from the true spirit and scope of the invention. Therefore, the above description should not be taken as limiting the scope of the invention which is defined by the appended claims. | Drug eluting vascular closure devices and methods for closing a blood vessel puncture site disposed at a distal end of a tissue tract are described. The devices and methods rely on a combination of the body's own natural mechanism to achieve hemostasis with bio-chemical agents to accelerate the hemostatic process. One method includes the steps of introducing a closure device through the tissue tract and deploying an expansible member at a distal end of the device within the blood vessel to occlude the puncture site. A bio-chemical sealing member disposed proximal the expansible member is then displaced so as to expose a bio-chemical region or release region of the device. At least one bio-chemical agent is thereafter released from the device and into the tissue tract to accelerate the occlusion process in the tract. | 0 |
The present application is a division of U.S. Pat. application Ser. No. 300,718 filed Oct. 25, 1972, copending herewith, and now abandoned.
CROSS-REFERENCE TO RELATED APPLICATION
The present invention relates to methods of displaying waveforms, such as those indicating seismic and geophysical measurements, as does my co-pending application "Multi-Variable Seismic Display" (U.S. Ser. No. 300,672, filed Oct. 25, 1972, as well as other waveforms indicating scientific or technical measurements.
BACKGROUND OF INVENTION
1. Field of Invention
This invention is concerned with the display in color of variables which may be presented as waveforms and graphs. It is also concerned with the combined display, for visual appraisal, of several quantities which are different functions of the same variable or variables.
2. Description of Prior Art
In several branches of science useful conclusions can be drawn from variations of several quantities as a function of a common variable. One example is in seismic exploration, where the geological value of the conventional display of seismic vibration as a function of reflection time may be enhanced, by adding to the display further variables (such as interval velocity). Another example is in the interpretation of acoustic, electric, neutron and other logs taken in a borehole as a function of depth. Another example is in the interpretation of gravity and magnetic field readings taken as a function of distance along a profile. Another example is in the interpretation of medical waveforms (such as electroencephalographic signals as a function of time). Another example is in the formulation of a fault-condition diagnosis from a number of transducers (which may be in an engine, or a computer, or in the human body).
Where the expected nature of the relationship between several functions can be expressed mathematically, it has been usual to employ the techniques of cross-correlation to obtain a numerical measure of this relationship. In appropriate applications these techniques were very powerful, being able to find relationships between functions when such relationships could not be detected by visual examination of the corresponding waveforms. However, cross-correlation techniques were better than visual examination only if the integration intervals were long enough to include many cycles of variation and if there is no significant variation of the common-variable axis. Further, the need for visual correlation remained in every case where a skilled human judgment had to be made on the significance of the correlation, and where this skill had not yet advanced to the stage where the basis for judgment could be quantified. These situations existed in the aforementioned examples of geology, log analysis, medicine and brain research, and in other technological arts.
SUMMARY OF INVENTION
Briefly, the present invention provides a new and improved method for juxtaposed or superposed display, in color, of a plurality of physical measurements which represent different functions of the same variable. These displays may be associated with the display of further such functions in the variable-area or variable-density form of optical recording of images on film. It has been found that such displays convey to the eye of the analyst, very quickly and easily, information on various types of relationships which exist between the several functions.
Accordingly it is an object of the invention to display a plurality of functions of the same or a related variable in the form of one or more colored traces.
It is a further object to provide a composite display of a plurality of functions of the same or a related variable, in which one such function is displayed in variable-area form and in which the color of the area normally black or normally white may be modulated in accordance with a further such function or functions.
It is a further object to provide a composite display of a plurality of functions of the same or a related variable, in which one such function is displayed in conventional variable-density form and in which the other functions are used to modulate the color of the light or dark parts of the variable-density trace.
The invention therefore provides a method of making a combined display of a plurality of functions of the same or a related variable, by preparing each such function in a form suitable for display as a trace of a distinctive color, whose linear extent represents the independent variable and in which the intensity of color represents the magnitude of the function, and by merging the plurality of such displays so that particular relationships between the magnitudes of the several functions are characterized by particular mixed colors.
It also provides a method of making a combined display of a plurality of functions of the same or a related variable by constructing for each such function a colored trace whose linear extents represents the independent variable and whose local color changes to represent the local magnitude of the function, and by arranging such plurality of traces in appropriate positions relative to each other in order to facilitate visual appraisal.
It also provides a method of associating either of the above plural displays with the display of an additional function represented in black or shades of grey by the superposition of a variable-area or variable-density trace.
It also provides a color key by which the local color of a trace may be interpreted quantitatively in terms of the variable it represents.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 shows three functions of the same variable, together with their separate and combined representations as colored traces.
FIG. 2 shows a single function of a variable, the manner of resolving the variable into three colored traces, and the superposition of the latter to yield one multi colored trace representative of the variable.
FIG. 3 shows the application of the technique of FIG. 2 to the problem of contouring.
FIG. 4 illustrates the technique of superposing a variable-area trace representing one variable function and a colored trace representing another variable function.
FIG. 5 shows the application of the invention to a problem in seismic prospecting. It represents, in four vertical waveforms: a variable-area seismic trace displayed with true amplitude relationships, the same trace after amplitude equalization, a measure of reflection strength for the first two events and the general manner of its representation in color and a measure of the stacking coherence of the reflection events on the assumption that the first two events are primary reflections and that the third is a multiple.
FIG. 6 shows, in block-diagram form, the stages of operating on three input variables to make one or more colored traces, and the manner of superimposing a fourth variable in variable-area form.
FIG. 7 shows how the plotting operations of FIG. 6 may be accomplished simultaneously, using a color cathole-ray-tube.
FIG. 8 shows how the plotting and printing operations of FIG. 6 may be accomplished simultaneously, using three modulatable light sources of distinctive colors and colour photographic material.
FIG. 9A shows how the plotting operations of FIG. 6 may be accomplished sequentially using a single modulatable light source and black-and-white photographic material; and FIGS. 9B and 9C show two variations on the color printing operation which may be associated with FIG. 9A.
FIG. 10 shows how a single variable may be processed to yield three variables in form suitable for input to FIG. 6.
FIG. 11 illustrates the addition of a color key to the display of one or more variables in color.
DESCRIPTION OF PREFERRED EMBODIMENT
In the drawings FIG. 1 illustrates one form of display according to the present invention. Waveforms 1, 2 and 3 are displays of three signals of functions of a common variable; these might represent, for example, different physical measurements, obtained in a borehole, as a function of depth in the borehole. With a first embodiment of the present invention, each such variable is plotted as a variable-density trace of a distinctive color. As shown at 4, the trace corresponding to function 1 is displayed in shades of red; three densities of red are used, to represent the three levels present in the function in waveform 1, and these three densities are given density levels or values 0, 1 and 2. Similarly the second function in waveform 2 is represented in FIG. 1 as a trace 5 exhibiting three density levels of green, and the third function in waveform 3 as a trace 6 exhibiting three density levels of blue. The three traces may be of equal width, and plotted to the same scale of the independent (vertical) variable of depth; the three colors are selected as being distinctive, and may be the primary colors, their complements, or any other suitable hues. The present invention then provides for the superposition of these three traces to yield a composite trace 7. This trace exhibits color variations, as indicated (FIG. 1), which represent and identify particular combinations of values for the three contributory functions or waveforms 1, 2 and 3. It has been found that such a display according to the present invention is of great value for the visual identification of particular borehole conditions which may be detected or discerned only as a combination or resultant of several effects.
FIG. 2 illustrates another form of display according to the present invention, representing in different colors different levels or values of a single variable function. Waveform 8 is a form of such a function, having in this case five levels of variation. From this single function are constructed in a manner to be set forth below, three variable-density traces 9, 10 and 11, colored in three distinctive colors. As has been set forth, these colors may be the primary colors or their complements. It should be understood that although in the example illustrated the five levels of variation in the waveform 8 are represented with only two levels of density for each of the three colored traces, the practice of the invention is not limited to this particular example. The three traces 9, 10 and 11 are superposed to form the composite trace 12, in which the five levels of variation in the original waveform 8 are represented by five distinguishable colors as indicated (FIG. 2). By extension of the principle of this embodiment, a continuum of values for the original waveform may be represented by a continuum of hues across the whole range of primary and mixed colors.
FIG. 3 illustrates an application of this embodiment to the technique of contouring. In several forms of geophysical exploration, for example, it is desirable to contour the geophysical measurements which are made along lines. The lines are assembled forming a grid which is plotted on a map. In FIG. 3 these lines are represented, in their assembled positions on the map, by colored traces 13. In FIG. 3, the value of the measurement at positions along each line is represented by a numeral from 1 to 5, plotted in the appropriate positions for each of the lines on the grid. It should be understood that each of the numbers 1 through 5 represent a particular color (for example, from blue for low level to red for high level measurements as in FIG. 2). In this way contouring lines 14 in the conventional sense are hardly necessary; the high measurement areas stand out as red portions where the lines cross them, and the low areas are indicated in a like manner as blue. The merit of this display, contrasted to one in simple variable-density, is the increased dynamic range and the increased visual impact afforded by the color in the traces. An analyst using this method can gain a prompt appraisal of the extent and location of different measurement levels from the amount and placement of the different colors in the grid.
FIG. 4 illustrates superposition of a colored trace on a conventional variable-area trace. The terms "variable-area" and "variable-density" as used hereinbelow are used in the sense established in the technology of optical recording of sound on film; a variable-area track or trace is one in which the black area of a partly-black-partly-white trace is modulated in accordance with the dependent variable, and a variable-density track or trace is one in which the grey density of a constant-width trace is so modulated. The area 15 which is black on the variable-area trace to indicate a variable being measured remains black, but the area 16 which is white in the prior art is colored, as will be set forth. In this way two variables 17 and 18 are displayed on the same trace, and their inter-relation is more easy to perceive. Equally well, the information displayed in variable-area form may be displayed in variable-density form; in this case the color is clearly seen in those regions in which a conventional variable-density trace would be white or grey. Several examples applications of the technique of FIG. 4 are set forth below.
The first example is the addition of interval-velocity information to a seismic cross-section. Such cross- sections normally involve side-by-side display of hundreds of conventional variable-area or variable-density traces, each representing the reflection response of the layered earth observed from a particular point on the surface. According to this embodiment of the invention, there is superimposed (on some or all of these traces) color information representing auxiliary seismic variables which are, like the reflection traces themselves, functions of reflection time. Typical of these auxiliary seismic variables is the interval velocity-computed, by techniques well known in the art, between particular reflectors (see, for example, "Velocity Spectra - Computer Derivation of Velocity Function" by Taner and Koehler, Geophysics 1969 vol. 34 p. 859). Such computations may result in interval-velocity values between 1500 and 6500 meters/second, and it has been found that these may be displayed conveniently according to the present invention in from approximately 20 to 30 steps of color from blue to orange-brown, with each successive step representing a velocity increment of 150 or 200 meters/second. When the computations of interval velocity are performed and displayed continuously across the seismic section, there results a very intelligible display which adds easily-assimilated information on the lithology of the area. Further, the color display so formed removes the need for lateral averaging of the interval velocity values; the analyst can assess without difficulty both the mean color, indicating velocity, and the scatter of the measurements.
A second example of an auxiliary variable which may be superimposed in color on a seismic section is an estimate of cross-dip. This is a measure of the component of reflector dip transverse to the line of profile, obtained by scanning in this direction across the results obtained by a three-dimensional field technique (see, for example, "Three-Dimensional Seismic Method" by Walton, Geophysics 1972, vol. 37, p. 417). The auxiliary variable, in this case, is a measure of cross-dip obtained from the cross-members of the spread. This is conveniently done by first scanning the profile itself for reflection alignments extending each side of the intersection with the cross-members, and then by searching for corresponding alignments on the cross-members. Thus a time waveform may be obtained at each intersection, in which positive cross-dips are represented by corresponding positive numbers, in which negative cross-dips are represented by corresponding negative numbers, and in which all values not associated with a reliable cross-dip measurement are set to zero. If desired, these waveforms may be given a slight degree of averaging in the direction of the profile. They then become the auxiliary variable to be displayed in combination with the reflection profile itself. They may be displayed, for example, so that reflection alignments which originate well in front of the plane of section are colored red, those in the plane of section are colored yellow, and those which originate well behind the plane of section are colored blue with appropriate gradation between these extremes.
A third example of an auxiliary variable which may be superimposed in color on a seismic section is a measure of coherence between the elements of common-depth-point gathers entering the stack, as determined by computing according to the method disclosed in "Semblance And Other Coherency Measures For Multichannel Data"by Neidell and Taner, Geophysics 1971, vol. 36, p. 482. This gives an immediate and forceful indication of those reflectors which are shown to be primary reflectors on the basis of the velocity distribution employed.
A fourth example is a measure of the strength of individual reflections, which may be adjusted by reference to a known reflection coefficient and to measured spectral change in order to represent effective reflection coefficients, as determined by computing according to the method disclosed in "Reflections on Amplitudes" by O'Doherty and Anstey, Geophysical Prospecting 1971, pp. 430-458. This is illustrated in FIG. 5, as a suitable example of the general principle of the display in color of auxiliary seismic measurements.
In FIG. 5, a seismic reflection trace without time-varying amplitude manipulations such as automatic gain control or equalization is shown at 19, in the familiar variable-area representation. Three reflection events are depicted: a high-amplitude primary reflection at 20, a low-amplitude primary reflection at 21, and a low-amplitude multiple reflection at 22. It is a common observation that if the entire trace is displayed at a level appropriate to reflection 20, then the low-amplitude multiple reflection 22 is kept suitably subdued but the low-amplitude primary reflection 21 cannot be seen as clearly as the analyst or interpreter would wish. Therefore it is usual to apply some sort of trace equilization, by which different scale factors are applied to the reflections to keep their amplitudes comparable; the effect of this is seen in the equalized trace 23. However, this has three well-known disadvantages: the true amplitude relationship between different primary reflections is lost, the multiple reflections attenuated by the stacking process are restored to obtrusive amplitudes, and the background noise is likewise elevated in amplitude.
In this application of the present invention the color of the equalized trace 23 is modulated by a measure of the strength of the reflections on the original unequalized trace 19. An example of this measure of strength appears at 26. To a degree, as disclosed in the "Reflections on Amplitudes" reference above, this measure of strength may be interpreted in terms of the apparent reflection coefficient of the reflecting interface.
This strength variable is then used to modulate the color of either the "black" part 24 or the "white" part 27 of the variable-area trace 23. Thus reflections with high real amplitude (such as 28) are modulated to a red color; reflections with low real amplitude (such as 29) are modulated to a blue color. Intermediate amplitudes are represented by intermediate spectral hues, as shown generally by the color levels 30.
This approach is sufficient to distinguish between reflections of high and low amplitude (such as distinction between 20 and 21) but does not itself distinguish between low-amplitude primary reflections and low-amplitude multiple reflections (such as distinction between 21 and 22). Neither does it permit discrimination between reflections and noise. Therefore, in a further embodiment of the invention, the information from the strength variale 26, determined as set forth above, is combined with that from the coherence variable 25, determined in the manner set forth. For example, the strength variable 26 is plotted in the appropriate spectral color only if the coherence variable 25 exceeds a preset threshold value which may be fixed or time variant. Such a threshold is shown generally by the dashed line 31. Since the coherence exceeds the threshold 31 both on the high-amplitude event 20 and the low-amplitude event 21, both are modulated to their corresponding color. However, since the coherence on the multiple reflection 22 is poor, the latter is either left or colored to a natural grey. This display, therefore, identifies those reflections which are both strong and primary on the basis of the velocity distribution employed, indicating these as the ones appropriate to the calculation of interval velocities.
It should be understood that in the foregoing material the word "strength" may be used to represent any one of several possible measures of magnitude of the reflection signal.
In particular, the strength may be represented by the numerical (that is, `rectified`) value of the amplitude of the seismic signal, or by the square or other power of the amplitude, or by a time-averaged or smoothed version of either of these. A preferred measure is that of the instantaneous energy of the signal, evaluated by summing the potential energy and the kinetic energy represented by the waveform, according to techniques well known in the art. This measure of strength has the virtue of being smoothly varying, and of stressing that part of the seismic event which may be expected to travel with a velocity most closely approximating to that characteristic of the transmitting medium. However, other measures may be used, including in particular a simple smoothed version of the rectified amplitude.
Whatever the measure of strength employed, the resulting color display may be calibrated in terms of the apparent reflection coefficient of the seismic events. Thus it may be arranged that apparent reflection coefficients in the range above 0.2 are indicated by a red color, those between 0.15 and 0.2 by orange, between 0.1 and 0.15 by yellow, between 0.05 and 0.1 by green and between 0 and 0.05 by blue.
FIG. 6 illustrates the method steps of forming the display of FIG. 1. In this figure the three variable functions or waveforms 1, 2 and 3 are recorded on three tapes 32, 33 and 34, in the conventional manner, from which they may be called out on demand. At step 35 they are each then suitably processed (for example, filtered) according to techniques well known in the art, and then scaled and formatted in a manner appropriate to the type of plotter to be used. The plotting step 36 plots each of the three signals in a distinctive color, with the intensity of each color being related to the level of the particular associated original variable 32, 33 and 34, and further allows the superposition of light of three distinctive colors and the recording of the superposition of these three colors on the color print 37.
FIG. 7 illustrates generally how the function of step 36 (FIG. 6) is accomplished by means of a color cathode ray tube 38, which may be of any type well known in the art. The three plot signals 39, 40 and 41 correspond to the output of the three formatting stages 35 in FIG. 6. The final color print 37 may be made by contact exposure on the face of the cathode-ray tube (for which usage the faceplate of the tube is preferably of the fiberoptic type), or by standard photographic techniques using a conventional camera 42.
FIG. 8 illustrates generally how the function of step 36 (FIG. 6) is accomplished by the modulation of three sources of colored light. For example, these sources may be lasers 43, 44 and 45, each of a distinctive color and connected to a Pockel-cell modulator 46, 47 and 48. The three light beams are combined in lens 49 and focused onto color film 50. The representation of the independent variable is then formed by motion of the combined light image 51 relative to the film 50. This may be by scanning of the image across a stationary film by means of moving mirros (not shown) or by movement of the film 50 by means of the traversing mechanism shown generally at 52. It should be understood that the combination of lasers 43, 44 and 45 and modulators 46, 47 and 48 may be replaced by alternative sources of light. Glow-modulators, incandescent lamps and light-emitting diodes are examples of alternative light sources and each of these may be used in combination with optical filters to improve the separation of the colors.
FIG. 9A illustrates generally how the function of step 36 may be accomplished by the sequential use of a single modulatable light source. The modulation apparatus 55 is connected to the three plot-control signals 39-41 in turn, as indicated by the switch 53. A separate variable-density trace is made on a strip of monochrome film 57 in combination with the optical system 56 and a traversing mechanism (not shown, but similar to that illustrated at 52 in FIG. 8) for each of the three plot-control signals. Each of the three traces so made is then dyed by well-known chemical means (not shown) to a suitable distinctive color.
The three film strips 57a, 57b and 57c so formed by the apparatus of FIG. 9A carrying these colored traces are then placed in registration in front of a broad light source 58 (FIG. 9B) and photographed by a conventional camera 42.
An alternative method to that of FIG. 9B is that the final color print 60 (FIG. 9C) is made by three separate exposures to the light source 58, each with a distinctive color of light. Light from the broad source 58 is filtered through optical filter 59 and used to expose color material 60 through the first monochrome film 57a; subsequent exposures of the other two monochrome films 57b and 57c, in registration, are made through different optical filters 59 having distinctive colors.
As set forth hereinbefore, the three colors employed may conveniently be the primary colors or their complements, according to the order and number of photographic processes and the final effect desired. In a preferred embodiment of the technique represented by FIGS. 6, 9A and 9C, the processing steps 35 include the complementation of the variable function (for example, by its subtraction from a fixed large number) so that the plot instructions 39, 40 and 41 represent a negative photographic image. For example, for a variable function 32 due to be represented by the intensity of red on the final print 37, a large value of the variable 32 is represented by an instruction 39 to plot at a light-grey density on monochrome film 57. When the optical filter 59 is blue-green, an intense blue-green light is then transmitted through the light-grey density of the film 57 to the color print material 60. This produces, after photographic processing, an intense red coloration at the trace position appropriate to the said large value of the variable 32, due to the heavy blue-green filter 59. Correspondingly, a small value of the variable 32 produces a dark-grey density on film 57, a weak blue-green illumination of the print 60, and a weak red coloration on the processed print 60. Similar processes are used for variable 33, employing a red-green filter 59 and producing a blue image on the print 60, and for variable 34, employing a red-blue filter 59 and producing a green image on the print 60. With this technique, a suitable material for the print 60 is Ektacolor RC37, marketed by Kodak Limited.
As set forth with respect to FIG. 4, it is desirable to superimpose a variable-area trace 15 on the colored trace, with the variable-area trace representing a fourth variable. In Fig. 6 the steps corresponding to this additional input are shown in phantom; the variable itself is derived from storage medium 62, suitably scaled and formatted in the manner set forth at step 35, and plotted in variable-area plotter according to plot insturctions 63. The variable-area film so obtained from the plotter is used as a fourth stage in the above color-printing sequence; the film in this fourth stage is used in conjunction with the white light 58, either with no filter at 59 or with a special filter matched to give a good black from the light 58 and the paper 60 in use.
Although the "red" exposure, the "blue" exposure, the "green" exposure and the variable-area "black" exposure have been described in that order, any other convenient and suitable order may be used.
Also as discussed hereinbefore, the fourth input to be superposed on the color traces may be in variable-density instead of variable-area, with the operational sequence performed as described above.
In the sequence represented by Figs. 6, 9A and 9C, the function of step 35 is conveniently effected by a suitable digital computer and the function of step 36 by an LGP 2703 Laser Graphic Plotter developed by SIE - Dresser Industries of Houston, Texas. This machine and others of similar type represent a preferred means of performing the function of step 36, since they allow accurate digital control of photographic densitites.
In the aforesaid digital plotter, a monochrome photographic film is exposed by a laser beam, which builds up a complete photographic picture as a matrix of small dots. The intensity of each dot is under digital control; a 4-bit word associated with each dot defines 16 tones from black through 14 shades of grey to white (or clear). The beam scan defines one dimension of the display (normally taken as that of the independent variable), while the indexing of the film between scans defines the other dimension.
In the prior art, this plotter was used for making variable-density seismic cross-sections by reducing the dynamic range of the normal reflecton signal to 4 bits, by presenting each trace in turn to the computer controlling the plotter, and by building up the trace to the required width by making an appropriate number of identical scans.
Again in the prior art, this plotter was used for making variable-area seismic cross-sections by building up each trace as an appropriate number of different scans, the difference between scans being determined by a logical discrimination program designed to construct a variable-area trace in a stepwise manner. In this variable-area case only a single bit was used to define the condition of any dot on the scan.
In my copending application Ser. no. 300,672, referred to hereinabove, the method of controlling this plotter for the display of more than one variable function, in monochrome, is described in connection with seismic cross-sections. For example, the usual seismic vibration may be displayed as a variable-area trace, while a second numerical function, such as a measure of the coherence between several samples of the vibration, is displayed as density variations in the "black" part of the said variable-area trace. Alternatively, the second function may be used to deflect the "zero-deflection" position of the variable-area trace, or to modulate the "zero" grey-level value of a variable-density trace.
In the present invention the machine is used with the variable-area and variable-density plotting techniques described above. The three color-plot signals 39, 40 and 41 are used to make three separate variable-density traces (corresponding to traces 4, 5 and 6 in FIG. 1) in the manner set forth above for making variable-density traces. Similarly a variable-density grey trace may be made to be superimposed on the color trace. Also, a variable-area black-clear trace 15 to be superimposed on the color trace 16 (as in FIG. 4) may be prepared by the variable-area technique described above.
The techniques set forth above are also adapted to display of a single waveform in color (as in FIG. 2) and the superposition on such a color display of another variable in variable-area or variable-density form as set forth with respect to FIG. 5.
In FIG. 10, process steps for controlling a digital computer to perform the present invention are set forth. The waveform or variable to be displayed is available from storage means 64. It is scaled at process step 65 into a number n of incremental ranges corresponding to the number n of color steps to be displayed (for the example of FIG. 2, five steps). The working store 66 therefore contains all the samples input from storage 64, but these samples can have only one of the n possible values. For each of these possible values there is stored in a density table 67 the densities of the red, green and blue plots which will provide the final color corresponding to such sample value. An example table is given hereinafter. Operation step 68 causes the computer to search or look up, in the stored density 67, the red plot density table corresponding to each sample value in turn, and to output at 32 a string or series of red plot density values corresponding to the string or series of input samples constituting the original variable. Either simultaneously or sequentially, a like operation is then performed at steps 69 and 70 to obtain similar strings or series of green and blue plot density values; these are recorded at 33 and 34, respectively.
The three output storage media 32, 33 and 34 (which may be the same tape if the generation and/or plotting operations are done sequentially) correspond to the first three inputs of FIG. 6. Hence, application of the techniques described hereinbefore with reference to FIGS. 6 through 9 produces the desired final plot in color. Other variables 62 are added (as in FIG. 6, and described hereinbefore) in order to superimpose variable-area or variable-density traces on this color plot.
A suitable density table 67 for the case of the aforesaid LGP-2703 plotter, which has 16 possible densities defined by a 4-bit plotting instruction is set forth below. These 16 densities are denoted by levels 0 through 15, for which colors representing 26 sample-value ranges, are then synthesized from these 16 densities by the combinations shown in Table 1.
Table 1______________________________________Sample Blue Yellow-Green RedValue Density Density Density______________________________________0 15 0 01 13 0 02 11 0 03 10 0 04 9 1 05 8 2 06 7 3 07 6 4 08 5 5 09 4 6 010 3 7 011 2 8 012 1 9 013 0 9 114 0 8 215 0 7 316 0 6 417 0 5 518 0 4 619 0 3 720 0 2 821 0 1 922 0 0 1023 0 0 1124 0 0 1325 0 0 15______________________________________
This table is given solely for purposes of illustration, and major variations on it are possible and beneficial for particular purposes. One such variation is the provision of a greater or smaller number of color steps or sample values. Another variation is for the accommodation of particular photographic materials, light sources, filters of processing techniques. Another variation is to accomplish the optimum adaptation of the display to the nature of the variable being displayed (in particular, its amplitude distribution). Another variation is the provision of a bias to the display (for example, in the table above, the representation of sample values 0-3 by a constant blue density of 10). Another variation is for adaptation of the visual impact to the expected measure of error in the variable displayed. (An example of this occurs in the display of interval velocities superimposed on a seismic cross-section; the highest values of interval velocity are usually those which are least accurately measured, and it has been found best to display these in shades of brown and orange rather than in bright red.)
Table 2 gives density values which have been found particularly appropriate to the display of interval velocities. The 29 color shades may conveniently represent increments of 150 meters/second in interval velocity, with the first step beginning at 1500 meters/second.
Table 2______________________________________ IntervalSample Velocity, Colour Cyan Yellow MagentaValue m/s Density Density Density______________________________________ 0 1500 Indigo 14 0 14 1 1650 15 0 13 2 1800 15 0 12 3 1950 Blue 15 0 11 4 2100 15 0 10 5 2250 15 0 9 6 2400 15 0 6 7 2550 15 8 0 8 2700 15 9 0 9 2850 Green 15 11 010 3000 14 13 011 3150 13 15 012 3300 12 15 013 3450 11 15 014 3600 10 15 015 3750 9 15 016 3900 8 15 017 4050 Yellow 7 15 018 4200 0 15 519 4350 0 15 820 4500 0 15 1021 4650 0 15 1122 4800 Brown 0 15 1223 4950 0 15 1324 5100 0 15 1425 5250 0 15 1526 5400 0 11 1527 5550 0 9 1528 5700 Magenta 0 7 15______________________________________
The density values given in Table 2 are complemented in the manner set forth, in conjunction with the techniques of FIGS. 6, 9A and 9C, and with Ektacolor RC37 paper as set forth, so that they yield the colors indicated in the third column of Table 2 (with appropriate gradation therebetween).
Quantitative assessments of the variable displayed in color may be assisted during analysis if each ploted output sheet carries therewith a color key, and this constitutes an important part of the invention. As suggested in FIG. 11 (which is an example adapted to the illustration of Table 2), a main display 71 is accompanied by a color key 72. This color key 72 is a broad trace to which the sample values of the first column of Table 2 are applied in turn, producing the color gradation indicated by the third column of Table 2. The numerical values of the variable with which the colors of the key 72 are associated (that is, the second column of Table 2) are annotated by the side of the key 72 as a color calibration, as shown in part at 73. Thus a color displayed on the main display 71 may be matched by the analyst to the corresponding colour on the key 72, and thereby identified with a numerical value (or range of values) of the variable.
Although the practice of the invention has been described primarily with reference to specific examples, these examples do not limit the invention. The same techniques are appropriate wherever the interpretation of a plurality of variables is best done by a skilled human analyst, and where the problem is the optimum manner of transferring the interrelation between these variables to the analyst visually. | A new and improved method of forming color graphic displays from input data is disclosed. In the displays so formed differing colors quantitatively identify and indicate differing values or ranges of values of the data. The input data are processed to determine sample values for data display points, and numerical codes from an assignment table are assigned according to the sample values. The assigned codes are arranged into output sequences for each of plural component displays of the final display, and the component displays formed and displayed in superposition to form the color graphic display with colors therein graphically indicating the data. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to integrated circuit manufacturing, and more particularly to selectively exposing a material on a semiconductor substrate.
2. Description of Related Art
Photolithography is frequently used in semiconductor fabrication to selectively expose regions of a material on a semiconductor wafer or substrate. Typically, the wafer is cleaned and prebaked to drive off moisture and promote adhesion, an adhesion promoter is deposited on the wafer, a few drops of photoresist are deposited onto the spinning wafer to provide a uniform layer, the wafer is soft baked to drive off remaining solvents, the wafer is put into a photolithographic system and exposed to a radiation pattern, and then the photoresist is developed. Positive photoresist, in which the developer removes the irradiated regions, is usually used. The photoresist is further hard baked to improve its resistance, and then the wafer is subjected to an additive process (such as ion implantation) or a subtractive process (such as etching) using the photoresist as a mask. Thereafter, the photoresist is stripped.
Photolithographic systems often use a radiation source and a lens in conjunction with a mask or reticle to selectively irradiate the photoresist. The radiation source projects radiation through the mask or reticle to the lens, and the lens focuses an image of the mask or reticle onto the wafer. A mask transfers a pattern onto the entire wafer (or another mask) in a single exposure step, whereas a reticle transfers a pattern onto only a portion of the wafer.
The three major methods of optically transferring a pattern on a mask or reticle to a photoresist-coated wafer include contact printing, proximity printing, and projection printing. In contact printing, the mask is clamped against a photoresist-coated wafer. Although this optimizes image transfer and resolution, the contacting process results in mask defects. In proximity printing, the mask and photoresist are spaced by a small distance. Although this overcomes the defect problems associated with contact printing, it also requires extremely flat wafers and masks. In projection printing, lens elements or mirrors are used to focus the mask or reticle image on the photoresist, which is spaced from the mask or reticle by a large distance. Several projection printing techniques have been developed, including projection scanners and step and repeat systems. Projection scanners use a reflective spherical mirror to project the mask onto the wafer by scanning the wafer and the mask with a narrow arc of radiation. Step and repeat systems (steppers) project an image only onto a portion of the wafer. Multiple images of the reticle pattern are stepped and repeated over the entire wafer using multiple exposures. The reticle pattern is typically 2× to 20× the size of the image on the wafer due to reduction by the lens. However, non-reduction (1×) steppers offer a larger field, thereby allowing more than one pattern to be printed at each exposure.
Step and repeat systems often use a mercury-vapor lamp as the illumination source. In mercury-vapor lamps, a discharge arc of high-pressure mercury vapor emits a characteristic spectrum that contains several sharp lines in the ultraviolet region--the I-line (365 nm), the H-line (405 nm) and the G-line (436 nm). Step and repeat systems are designed, for instance, to operate using the G-line, the I-line, a combination of the lines, or at deep UV (240 nm). To obtain the proper projection, high power mercury-vapor lamps are used that draw 200 to 1,000 watts and provide ultraviolet intensity on the order of 100 milliwatts/cm 2 . In some systems, air jets cool the lamp, and the heated air is removed by an exhaust fan. The reticle is typically composed of glass with relatively defect-free surfaces and a high optical transmission at the radiation wavelength. Popular reticle glasses include soda-lime glass, borosilicate glass, and quartz. Quartz has a low thermal expansion coefficient and high transmission for near and deep ultraviolet light. Although quartz tends to be expensive, it has become more affordable with the development of high quality synthetic quartz material.
In general, the term "resolution" describes the ability of an optical system to distinguish closely spaced objects. The minimum resolution of a photolithographic system is the dimension of minimum linewidth or space that the machine can adequately print or resolve. While optical photolithography continues to be the dominant technology because it is well established and is capable of implementing sub-micron resolution at least as low as 0.35 microns using current equipment, as feature sizes approach 0.5 microns and below, and these features extend across wafer areas of a square inch and more, extensive efforts are being directed at developing alternative technologies. Electron-beam, ion-beam, and x-ray technologies have demonstrated patterning capabilities that extend beyond the limits of optical systems. Electron-beams and ion-beams can also directly write image patterns onto the photoresist without the use of a mask or reticle, for instance by using a controlled stage to position the wafer beneath the tool. However, these alternative approaches have certain drawbacks. For instance, electron-beam lithography has low throughput, x-ray lithography has difficulties with fabricating suitable masks, and ion-beam lithography has low throughput and difficulties with obtaining reliable ion sources.
Thus, workers in the art recognize that there are obvious incentives for trying to push the currently dominant technology (optical photolithography) into the fine-line region. Such an effort, if successful, has the potential for significantly better patterning capabilities.
Accordingly, a need exists for improvements in semiconductor processing techniques employing optical photolithographic systems in order to pattern fine-line dimensions of 0.5 microns and below.
SUMMARY OF THE INVENTION
The invention addresses the forementioned need by providing an improved method of selectively exposing a material over a semiconductor substrate. The method includes forming a material over a semiconductor substrate, forming a photosensitive layer over the material, projecting a first image pattern onto the photosensitive layer that defines a first boundary for the material, projecting a second image pattern onto the photosensitive layer after projecting the first image pattern such that the second image pattern partially overlaps the first image pattern and defines a second boundary for the material, and removing portions of the photosensitive layer corresponding to the first and second image patterns. In this manner, the photosensitive layer selectively exposes the material adjacent to the first and second boundaries while covering the material between the first and second boundaries. Advantageously, the first and second boundaries can be closer than the minimum resolution of the photolithographic system used to pattern the photosensitive layer.
Preferably, the material includes first and second portions adjacent to and on opposite sides of a central portion, the first boundary is between the first and central portions, the second boundary is between the central and second portions, the first image pattern covers the first portion without covering the central and second portions, and the second image pattern covers the second portion without covering the first and central portions.
It is also preferred that the first and second image patterns are formed using separate radiation exposure steps, and are essentially identical to and laterally shifted with respect to one another. The lateral shift reduces the size of a minimum linewidth region by irradiating a portion of the minimum linewidth region.
The first and second image patterns can be provided by projecting radiation through a reticle while the reticle has a first position with respect to the substrate, and then projecting radiation through the reticle while the reticle has a second position with respect to the substrate, with the second position laterally shifted with respect to the first position. Alternatively, the first and second image patterns can be provided by projecting radiation through a first reticle having a first radiation-transmitting pattern, and then projecting radiation through a second reticle having a second radiation-transmitting pattern, with the second radiation-transmitting pattern essentially identical to and laterally shifted with respect to the first radiation-transmitting pattern. Furthermore, the first and second image patterns can be laterally shifted with respect to one another along a single coordinate axis, or along first and second mutually orthogonal coordinate axes.
The invention is well-suited for forming extremely narrow gate electrodes using photoresist as the photosensitive layer and polysilicon as the material to be selectively exposed and subsequently etched. Advantageously, a polysilicon gate electrode formed using the present invention can have an extremely narrow length, for instance 0.2 microns and below.
These and other aspects of the invention will be further described and more readily apparent from a review of the detailed description of the preferred embodiments which follow.
BRIEF DESCRIPTION OF THE DRAWINGS
The following detailed description of the preferred embodiments can best be understood when read in conjunction with the following drawings, in which:
FIGS. 1A-1E show top plan views of successive process steps for forming a gate electrode using first and second essentially identical image patterns laterally shifted with respect to one another along a single coordinate axis in accordance with a first embodiment of the invention,
FIGS. 2A-2E show cross-sectional views of FIGS. 1A-1E, respectively,
FIGS. 3A-3B show reticle(s) for forming the image patterns of FIGS. 1A-1E, and
FIGS. 4A-4E show top plan views of successive process steps for forming a gate electrode using first and second essentially identical image patterns laterally shifted with respect to one another along first and second mutually orthogonal coordinate axes in accordance with a second embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings, depicted elements are not necessarily drawn to scale and like or similar elements may be designated by the same reference numeral throughout the several views.
FIGS. 1A-1E show top plan views of successive process steps for forming a gate electrode using first and second essentially identical image patterns laterally shifted with respect to one another along a single coordinate axis in accordance with a first embodiment of the invention, and FIGS. 2A-2E show cross-sectional views of FIGS. 1A-1E, respectively.
In FIGS. 1A and 2A, silicon substrate 102 includes an 8 micron thick P-type epitaxial surface layer with a <100> orientation and a resistivity of 12 ohm-cm. Preferably, the epitaxial surface layer is disposed on a P+ base layer (not shown). Substrate 102 is suitable for integrated circuit manufacture. A blanket layer of gate oxide 104, composed of silicon dioxide, is formed on the top surface of substrate 102 using tube growth at a temperature of 700° to 1000° C. in an O 2 ambient. Gate oxide 104 has a thickness in the range of 30 to 150 angstroms. Thereafter, a blanket layer of undoped polysilicon 106 is deposited by low pressure chemical vapor deposition (LPCVD) on the top surface of gate oxide 104. Polysilicon 106 has a thickness of 2000 angstroms. If desired, polysilicon 106 can be doped in situ as deposition occurs, or doped before being etched by implanting arsenic with a dosage in the range of 1×10 15 to 5×10 15 atoms/cm 2 and an energy in the range of 2 to 50 kiloelectron-volts. However, it is generally preferred that polysilicon 106 be doped during a later process step when a dopant is introduced into substrate 102.
Photoresist layer 108 is disposed on polysilicon 106. Photoresist layer 108 is deposited as a continuous layer and selectively irradiated using a photolithographic system, such as a step and repeat optical projection system, in which I-line ultraviolet light from a mercury-vapor lamp is projected through a reticle and a focusing lens to obtain image pattern 110 on photoresist layer 108. Image pattern 110 includes inner borders 112 and outer borders 114. Inner border 112a is adjacent and orthogonal to inner border 112b, inner border 112b is adjacent and orthogonal to inner border 112c, inner border 112c is adjacent and orthogonal to inner border 112d, and inner border 112d is adjacent and orthogonal to inner border 112a. Likewise, outer border 114a is adjacent and orthogonal to outer border 114b, outer border 114b is adjacent and orthogonal to outer border 114c, outer border 114c is adjacent and orthogonal to outer border 114d, and outer border 114d is adjacent and orthogonal to outer border 114a. Inner borders 112a and 112c are spaced by 0.4 microns, as are inner borders 112b and 112d. Outer borders 114a and 114c are spaced by 1.2 microns, as are outer borders 114b and 114d. Region 116 of photoresist layer 108 is not exposed to image pattern 110. The length of region 116 between borders 112a and 112c is 0.4 microns, and the width of region 116 between borders 112b and 112d is 0.4 microns. Similarly, the length of image pattern 110 between borders 112a and 114a, 112b and 114b, 112c and 114c, and 112d and 114d is 0.4 microns. This represents the minimum resolution (i.e. linewidth and spacing) of the step and repeat system. Therefore, if region 116 is used to define the length of a gate electrode in polysilicon 106, and anisotropic etching is used, then the gate length will be 0.4 microns. However, the present invention provides for far narrower gate lengths.
In FIGS. 1B and 2B, photoresist layer 108 is selectively irradiated again using the step and repeat system, and image pattern 120 is projected onto photoresist 108. Image pattern 120 includes inner borders 122 and outer borders 124, shown as the broken lines. Inner border 122a is adjacent and orthogonal to inner border 122b, inner border 122b is adjacent and orthogonal to inner border 122c, inner border 122c is adjacent and orthogonal to inner border 122d, and inner border 122d is adjacent and orthogonal to inner border 122a. Likewise, outer border 124a is adjacent and orthogonal to outer border 124b, outer border 124b is adjacent and orthogonal to outer border 124c, outer border 124c is adjacent and orthogonal to outer border 124d, and outer border 124d is adjacent and orthogonal to outer border 124a. Inner borders 122a and 122c are spaced by 0.4 microns, as are inner borders 122b and 122d. Outer borders 124a and 124c are spaced by 1.2 microns, as are outer borders 124b and 124d. Region 126 of photoresist layer 108 is not exposed to image pattern 120. The length of region 126 between borders 122a and 122c is 0.4 microns, as is the width of region 126 between borders 122b and 122d. Similarly, the length of image pattern 120 between borders 122a and 124a, 122b and 124b, 122c and 124c, and 122d and 124d is 0.4 microns.
Image pattern 120 is superimposed on image pattern 110 (or the region of photoresist layer 108 irradiated by image pattern 110) for the sake of comparison. However, it is critical to note that image patterns 110 and 120 are projected using separate exposure steps. That is, image pattern 110 is projected onto photoresist layer 108, the exposure is discontinued, and then image pattern 120 is projected onto photoresist layer 108. Therefore, although image patterns 110 and 120 partially overlap, image patterns 110 and 120 are not simultaneously projected onto photoresist layer 108. It should also be noted that image pattern 120 is essentially identical to, and laterally shifted by 0.2 microns along the x-axis with respect to image pattern 110. For instance, borders 114a and 124a are spaced by 0.2 microns, as are borders 112a and 122a, 112c and 124c, and 114c and 124c. Likewise, since image patterns 110 and 120 are not shifted with respect to one another along the y-axis, there is partial overlap and alignment between borders 112b and 122b, 112d and 122d, 114b and 124b, and 114d and 124d. The overlap between image patterns 110 and 120 occurs, for instance, in the 0.2 micron region between borders 112a and 124a, and in the 0.2 micron region between borders 114c and 124c. Of importance, region 128 of photoresist layer 108, which represents the overlap of regions 116 and 126, is outside both image pattern 110 and image pattern 120. In fact, region 128 is the only region of photoresist layer 108 inside borders 114 or borders 124 that remains unirradiated. The length of region 128 between borders 112c and 122a is 0.2 microns. Moreover, the length of region 128 is a function of the overlap between image patterns 110 and 120. The smaller the overlap (as border 112c approaches border 122a), the narrower region 128 becomes.
In FIGS. 1C and 2C, photoresist layer 108 is developed, and since photoresist layer 108 is positive-acting, the portions of photoresist 108 irradiated by image pattern 110, image pattern 120, or both are removed. As a result, photoresist 108 contains opening 130 that selectively exposes portions of polysilicon 106. For illustration purposes, region 128 of photoresist layer 108 defines first portion 134, second portion 136 and gate electrode portion 138 of polysilicon 106. First portion 134 and second portion 136 are adjacent to opposite edges of gate electrode portion 138. Boundary 140 (shown as broken lines) is located between first portion 134 and gate electrode portion 138, and boundary 142 (shown as broken lines) is located between second portion 136 and gate electrode portion 138. As is seen, boundary 140 is aligned with border 122a, and boundary 142 is aligned with border 112c. Thus, first portion 134 and second portion 136 of polysilicon 106 are exposed by opening 130 in photoresist layer 108.
In FIGS. 1D and 2D, an anisotropic dry etch is applied through opening 130 that is highly selective of polysilicon 106. Photoresist layer 108 protects gate electrode portion 138 from the etch, but opening 130 exposes first portion 134 and second portion 136 to the etch. As a result, the etch completely removes first portion 134 to form first vertical edge 144 for gate electrode portion 138, and completely removes second portion 136 to form second vertical edge 146 for gate electrode portion 138. First vertical edge 144 is aligned with border 122a and corresponds to boundary 140, whereas second vertical edge 146 is aligned with border 112c and corresponds to boundary 142. Although the etch is highly selective of polysilicon, it is non-selective of silicon dioxide, so only a negligible amount of gate oxide 104 beneath first portion 134 and second portion 136 is removed, and substrate 102 is unaffected. Advantageously, gate electrode portion 138 provides an extremely narrow gate electrode, with a length of merely 0.2 microns, and a width of 0.4 microns, for an insulated-gate field-effect transistor (IGFET) such as an N-channel metal-oxide-semiconductor field-effect transistor (MOSFET).
In FIGS. 1E and 2E, photoresist layer 108 is stripped, thereby exposing gate electrode portion 138 and the remaining unetched regions of polysilicon 106.
As previously mentioned, image patterns 110 and 120 are essentially identical to and laterally shifted with respect to one another. FIGS. 3A and 3B illustrate alternative embodiments for using a reticle (or reticles) to form image patterns 110 and 120.
In FIG. 3A, a single reticle is used for providing both first image pattern 110 and second image pattern 120. Reticle 170 includes radiation-transmitting pattern 172 and radiation-blocking pattern 174. As is seen, radiation-transmitting pattern 172 corresponds to the configuration of first image pattern 110, as well as second image pattern 120, although the dimensions of radiation-transmitting pattern 172 are larger than those of image patterns 110 and 120 since the step and repeat system includes a reduction lens between reticle 170 and photoresist layer 108. Reticle 170 is constructed with a chrome pattern disposed on a quartz base. The chrome pattern provides radiation-blocking pattern 174, and includes through-holes, or openings, that define radiation-transmitting pattern 172. Reticle 170 is disposed in a first position, P1, with respect to substrate 102, during a first exposure step when radiation is projected through reticle 170 to form first image pattern 110 on photoresist layer 108. Thereafter, the radiation is discontinued, and reticle 170 is repositioned to a second position, P2, with respect to substrate 102. The repositioning of reticle 170 from position P1 to position P2 is depicted by arrows 176, between the broken lines extending from similar regions of reticle 170. Accordingly, reticle 170 is laterally shifted along the x-axis, but not the y-axis, in order to displace second image pattern 120 by 0.2 microns along the x-axis with respect to first image pattern 110. When reticle 170 is in position P2, radiation is projected through reticle 170 during a second exposure step to form second image pattern 120 on photoresist layer 108. Advantageously, reticle 170 can be repositioned (or stepped) using the step and repeat system, which has an alignment tolerance on the order of 0.03 microns, to provide the first and second image patterns using a single reticle.
In FIG. 3B, first and second reticles are used for providing first image pattern 110 and second image pattern 120, respectively. Reticle 180, which includes radiation-transmitting pattern 182 and radiation-blocking pattern 184, is essentially identical to reticle 170. Reticle 190, which includes radiation-transmitting pattern 192 and radiation-blocking pattern 194, is essentially identical to reticle 180, except that radiation transmitting pattern 192 (and thus radiation-blocking pattern 194) is laterally shifted with respect to radiation-transmitting pattern 182 (and thus radiation-blocking pattern 184). Radiation-transmitting pattern 182 corresponds to the configuration of first image pattern 110, and radiation-transmitting pattern 192 corresponds to the configuration of second image pattern 120, although the dimensions of radiation-transmitting patterns 182 and 192 and the displacement therebetween are larger than those of image patterns 110 and 120 since the step and repeat system includes a reduction lens between the reticle in use and photoresist layer 108. Reticle 180 is disposed in a first position with respect to substrate 102 during a first exposure step when radiation is projected through reticle 180 to form first image pattern 110 on photoresist layer 108. Thereafter, the radiation is discontinued, and reticle 180 is replaced with reticle 190. Since the displacement between first image pattern 110 and second image pattern 120 is provided by reticles 180 and 190, reticle 190 is disposed in the same position as reticle 180 with respect to substrate 102. The displacement between radiation-transmitting patterns 182 and 192 is depicted by arrows 186, between the broken lines extending from similar regions of reticles 180 and 190. Accordingly, radiation-transmitting pattern 192 is laterally shifted along the x-axis, but not the y-axis, with respect to radiation-transmitting pattern 182, in order to displace second image pattern 120 by 0.2 microns along the x-axis with respect to first image pattern 110. When reticle 190 is in the first position, radiation is projected through reticle 190 during a second exposure step to form second image pattern 120 on photoresist layer 108. Advantageously, although two reticles are required, the step and repeat system need not adjust the relative positions of the reticles with respect to the substrate to provide the desired displacement between the first and second image patterns.
Furthermore, since radiation-transmitting pattern 182 can be a small portion of the entire radiation-transmitting pattern of reticle 180, and the radiation-transmitting pattern 192 can be a small portion of the entire radiation-transmitting pattern of reticle 190, reticles 180 and 190 can form other image patterns with various amounts of displacement or overlap therebetween. For instance, reticles 180 and 190 can form a first gate electrode with a length of 0.4 microns using 100% overlap between a first set of essentially identical image patterns over a first region, a second gate electrode with a length of 0.3 microns using 75% overlap between a second set of essentially identical image patterns over a second region, a third gate electrode with a length of 0.2 microns using 50% overlap between a third set of essentially identical image patterns over a third region, and a fourth gate electrode with a length of 0.1 microns using 25% overlap between a fourth set of essentially identical image patterns over a fourth region. The relative positions of the radiation-transmitting patterns for reticles 180 and 190 can be adjusted by appropriate shifting of the database coordinates that define the configurations of the chrome patterns on the quartz bases.
FIGS. 4A-4E show top plan views of successive process steps for forming a gate electrode using first and second essentially identical image patterns laterally shifted with respect to one another along first and second mutually orthogonal coordinate axes in accordance with a second embodiment of the invention. In the first embodiment (FIGS. 1A-1E), the second image pattern is displaced with respect to the first image pattern along a single coordinate axis. Although this can provide a gate electrode with an extremely narrow length, in certain applications it may also be desirable to provide the gate electrode with an extremely narrow width. The primary difference between the second embodiment and the first embodiment is that in the second embodiment, the second image pattern is displaced with respect to the first image pattern along both the x-axis and y-axis. Unless otherwise noted, the elements for the second embodiment (substrate 202, gate oxide 204, etc.) are similar to elements of the first embodiment (substrate 102, gate oxide 104, etc.), and the description of related elements and process steps need not be repeated.
In FIG. 4A, photoresist layer 208 is disposed on polysilicon 206 (not shown), which is disposed on a gate oxide 204 (not shown), which is disposed on semiconductor substrate 202 (not shown). Image pattern 210 is projected onto photoresist layer 208. Image pattern 210 includes inner borders 212a, 212b, 212c and 212d, and outer borders 214a, 214b, 214c and 214d. Borders 212a and 214a, and 212c and 214c are spaced by 0.4 microns along the x-axis, and borders 212b and 214b, and 212d and 214d are spaced by 0.4 microns along the y-axis.
In FIG. 4B, image pattern 220 is projected onto photoresist layer 208. Image pattern 220, shown by the broken lines, includes inner borders 222a, 222b, 222c and 222d, and outer borders 224a, 224b, 224c and 224d. Borders 222a and 224a, and 222c and 224c are spaced by 0.4 microns along the x-axis, and borders 222b and 224b, and 222d and 224d are spaced by 0.4 microns along the y-axis. Thus, image pattern 220 is essentially identical to image pattern 210, except that image pattern 220 is displaced from image pattern 210 by 0.2 microns along the x-axis and 0.2 microns along the y-axis. As a result, region 228 of photoresist layer 208 has a length of 0.2 microns between borders 212c and 222a, and a width of 0.2 microns between borders 212d and 222b. This can be contrasted, for instance, with region 128 of photoresist layer 108, which has a width of 0.4 microns between borders 112d and 122b.
In FIG. 4C, the regions of photoresist layer 208 irradiated by first image pattern 210, second image pattern 220, or both are removed to selectively expose polysilicon 206, in FIG. 4D the exposed polysilicon is etched and removed, and in FIG. 4E photoresist layer 208 is stripped. Advantageously, gate electrode portion 238 has a length of 0.2 microns and a width of 0.2 microns.
Of course, image patterns 210 and 220 can be provided by stepping reticle 170 along both the x-axis and y-axis, or alternatively, by shifting radiation-transmitting pattern 192 of reticle 190 along both the x-axis and y-axis with respect to radiation-transmitting pattern 182 of reticle 180.
After the gate electrode (such as gate electrode portion 138 or 238) is formed, N-type source/drain regions for an N-channel MOSFET are formed in substrate 102. For instance, lightly doped source/drain regions are introduced by subjecting the structure to ion implantation of arsenic, at a dosage in the range of 1×10 13 to 5×10 14 atoms/cm 2 and an energy in the range of 2 to 50 kiloelectron-volts, using the gate electrode as an implant mask, so that lightly doped source/drain regions are self-aligned to the gate electrode and are doped N- with an arsenic concentration in the range of 1×10 17 to 1×10 18 atoms/cm 3 and a junction depth in the range of 100 to 1500 angstroms. Thereafter, an oxide layer with a thickness in the range of 600 to 2000 angstroms is conformally deposited over the exposed surfaces by CVD at a temperature in the range of 300° to 400° C., and the structure is subjected to a reactive ion etch (RIE) that forms sidewall spacers adjacent to the edges of the gate electrode and that removes the regions of gate oxide 104 outside gate electrode and spacers. Thereafter, heavily doped source/drain regions are implanted into substrate 102 by subjecting the structure to ion implantation of arsenic, at a dosage in the range of 1×10 15 to 5×10 15 atoms/cm 2 and an energy in the range of 2 to 50 kiloelectron-volts, using the gate electrode and spacers as an implant mask. The heavily doped source/drain regions are self-aligned to the spacers and are doped N+ with an arsenic concentration in the range of about 1×10 18 to 1×10 19 atoms/cm 3 and a junction depth in the range of 200 to 3000 angstroms. Preferably, the junction depth of heavily doped source/drain regions exceeds that of lightly doped source/drain regions, and the heavy dose of arsenic also provides sufficient doping to render the gate electrode conductive. Finally, the structure is annealed to remove crystalline damage and to activate and drive-in the implanted arsenic by applying a rapid thermal anneal on the order of 950° to 1050° C. for 10 to 60 seconds. The implanted arsenic in substrate diffuses both laterally and vertically, so that the source regions merge to provide a source and the drain regions merge to provide a drain.
Further processing steps in the fabrication of IGFETs typically include forming a thick oxide layer over the active regions, forming contact windows in the oxide layer to expose the gate electrode, source and drain, forming appropriate interconnect metallization in the contact windows, and forming a passivation layer over the interconnect metallization. In addition, subsequent high-temperature process steps can be used to supplement or replace the anneal step to provide the desired anneal, activation, and drive-in functions. These further processing steps are conventional and need not be repeated herein. Likewise the principal processing steps disclosed herein may be combined with other steps readily apparent to those skilled in the art.
The present invention includes numerous variations to the embodiments described above. For instance, the image patterns can be projected onto a photosensitive layer. The material to be selectively exposed through openings in the photosensitive layer can be a nitride, an oxide, a metal, a semiconductor, or any other material disposed on a semiconductor substrate. Different amounts of overlap (or lateral shifting) between the image patterns will result in different sizes and configurations of the exposed region of the material. If desired, three or more image patterns can be employed. Once selectively exposed, the material can be subjected to either an additive or subtractive operation.
The invention is particularly well-suited for fabricating N-channel MOSFETs, P-channel MOSFETs, CMOS devices and other types of IGFETs, as well as integrated capacitors, interconnect vias and lines, and various other circuit elements, particularly for high-performance microprocessors where high circuit density is essential. Although only a single FET has been described for purposes of illustration, it is understood that in actual practice, many devices are fabricated on a single semiconductor wafer as widely practiced in the art. Accordingly, the invention is well-suited for use in an integrated circuit chip, as well as an electronic system including a microprocessor, a memory and a system bus.
Those skilled in the art will readily implement the steps necessary to provide the structures and methods disclosed herein, and will understand that the process parameters, materials, and dimensions are given by way of example only and can be varied to achieve the desired structure as well as modifications which are within the scope of the invention. Variations and modifications of the embodiments disclosed herein may be made based on the description set forth herein, without departing from the scope and spirit of the invention as set forth in the following claims. | A method of selectively exposing a material over a substrate is disclosed. The method includes forming a material over a semiconductor substrate, forming a photosensitive layer over the material, projecting a first image pattern onto the photosensitive layer that defines a first boundary for the material, projecting a second image pattern onto the photosensitive layer after projecting the first image pattern such that the second image pattern partially overlaps the first image pattern and defines a second boundary for the material, and removing portions of the photosensitive layer corresponding to the first and second image patterns. Preferably, the first and second image patterns are essentially identical to and laterally shifted with respect to one another. In this manner, the photosensitive layer selectively exposes the material adjacent to the first and second boundaries while covering the material between the first and second boundaries, and the distance between the first and second boundaries decreases as the overlap between the first and second image patterns decreases. Advantageously, the first and second boundaries can be closer than the minimum resolution of the photolithographic system used to pattern the photosensitive layer. | 6 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation from U.S. patent application Ser. No. 13/402,506, filed Feb. 22, 2012, and entitled “INTERNET SIP REGISTRATION/PROXY SERVICE FOR AUDIO CONFERENCING”, the entire contents of which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
This disclosure relates to audio conferencing and in particular to systems and methods for providing audio conferencing to uses of software phones.
BACKGROUND OF THE INVENTION
There is a growing need to allow valid Internet softphone users to gain access to an audio conferencing bridge without compromising security (Encryption and Authentication), and without manually building SIP trunks for each user.
SUMMARY OF THE INVENTION
To enable load balancing and the like for audio conferencing systems of an audio conferencing network, a DNS server may receive a DNS lookup from an internet softphone and return a prioritized list of audio conferencing system identities. The internet softphone may select an audio conferencing system and forward a SIP Invite to a bridge interface layer, such as a Bridge interface layer, of the respective audio conferencing system. If the SIP Invite does not generate a successful connection or generates a timeout, the internet softphone forwards the SIP Invite to the next prioritized Bridge interface layer in the list.
In one aspect of the disclosure, there is provided an audio conferencing network comprising a plurality of audio conferencing systems, each audio conferencing system comprising an audio conferencing bridge and a Bridge interface layer. The network further comprises at least one internet softphone and a DNS Server. The DNS server may be configured to receive a DNS lookup request from the internet softphone and return a list of one or more of the audio conferencing systems. The at least one internet softphone is configured to receive the list of one or more of the audio conferencing systems and provide a SIP Invite to the Bridge interface layer of a first of the audio conferencing systems in the list.
In one aspect of the disclosure, there is provided a method for connecting an internet softphone to an audio conference. The method may comprise providing a DNS lookup request from the internet softphone to a DNS Server, receiving a list of one or more of the audio conferencing systems from the DNS server, and providing a SIP Invite to the Bridge interface layer of a first of the audio conferencing systems in the list.
In one aspect of the disclosure, there is provided non-transitory computer-readable storage medium comprising instructions for receiving a DNS lookup request in a DNS Server from an internet softphone, generating a list of audio conferencing systems based on the request, and providing the list to the internet softphone.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will now be made, by way of example only, to specific embodiments and to the accompanying drawings in which:
FIG. 1 shows SIP server and a SIP Register process;
FIG. 2 shows a SIP Invite process;
FIG. 3 shows a SIP Invite and Refer process;
FIG. 4 shows a SIP Invite and 302 Redirect process;
FIG. 5 shows an alternative SIP Invite and 302 Redirect process; and
FIG. 6 shows a SIP Invite with load balancing.
DETAILED DESCRIPTION OF THE INVENTION
As outlined broadly above, there is a requirement to allow Internet VoIP callers to gain access to audio conferencing platforms via secure, trusted means.
One option is to allow Internet VoIP users to register with a Bridge Interface Layer (such as a SIP server) associated with the audio conferencing bridge, and subsequently place calls to the audio conferencing bridge numbers using SIP. Validation of users may be handled by Authentication, rather than having to setup a SIP trunk for each end-point. In the following, there will be described a Bridge Interface Layer that can fulfill the registrar, proxy and authentication services required for allowing Internet VOIP users to participate in calls on an audio conferencing platform, in a secure, authenticated and encrypted manner.
In FIG. 1 , there is a shown a system 10 including a Bridge Interface Layer 12 . The Bridge Interface Layer 12 provides a proxy service, a location service and Registration service. An authentication database may be included in the Bridge Interface Layer or may be a separate system accessible from the Bridge Interface Layer.
The Bridge Interface Layer 12 processes inbound SIP REGISTER requests and stores location information (actual IP address of end-point) in a logical database. The Bridge Interface Layer is used in conjunction with Authentication (described below) to validate callers against a known database of users. The Registrar Service receives REGISTER requests from SIP UAs and updates its location service appropriately. Using the registrar function, the service provider can receive calls from any SIP UA 22 using a unique SIP-URI.
The Bridge Interface Layer 12 processes inbound SIP INVITE requests and routes calls to the appropriate end-point (such as an audio conferencing bridge or other registered end-points). The Bridge Interface Layer is also used in conjunction with Authentication (described below) to validate callers against a known database of users. The Bridge Interface Layer 12 routes SIP requests from a SIP UA 22 to the most appropriate endpoint based on its registrar database or other routing database. The Bridge Interface Layer 12 can also support SIP redirect features if needed, as will be described in greater detail below.
Authentication may be used to validate the identity of users (via username/password) that are making inbound SIP requests. The authentication processes, described in more detail below, can be used for multiple SIP request types e.g. REGISTER and INVITE. For encryption, a certificate authority (CA) may be used to sign SIP and RTP messages that traverse unsecure networks (Internet). Encrypted communications over the Internet (un-secure) is a must for SIP (TLS) and RTP (SRTP). Any man-in-the-middle attack could retrieve sensitive information if encryption is not used. By specifying authentication settings on REGISTER or INVITE requests, the service provider can limit & manage calls that pass through the SIP Server 12 to a known user base (username/password).
The Bridge Interface Layer 12 can be used to connect a customer SIP user agent softphone 22 to an audio conferencing bridge 24 via internet 26 and Session Border Controller (SBC) 28 . The softphone 22 may be a softphone proprietary to the audio conferencing bridge 24 or may be a 3 rd party softphone.
FIG. 1 shows a process for registering the customer. At step 101 , an initial inbound REGISTER request is received by the Bridge Interface Layer 12 using a suitable IP Address or Domain Name. All SIP messaging is encrypted on the unsecure side of SBC (TLS) 28 and unencrypted on secure side of SBC 28 . At step 102 , the Bridge Interface Layer 12 returns a 401 Unauthorized response (or other suitable SIP response code), indicating authentication for REGISTER requests is required, and includes a challenge for authentication.
At step 103 , the user re-sends REGISTER plus the authentication challenge response. In one embodiment, the challenge response may be an MD5 hash of various data including username and password. However, many different challenge/authentication methods will be apparent to a person skilled in the art and the specific authentication method is not pertinent to the present embodiments.
At step 104 , the authentication response is validated via a transaction to the user DB to find username and password. If valid, the location information is stored in the Bridge Interface Layer 12 . Step 105 is a reply to user with 200 OK indicating REGISTER request was accepted.
In FIG. 2 , there is shown an INVITE process on the system 10 . At step 201 , an initial inbound INVITE request is received by Bridge Interface Layer 12 . As for the REGISTER process described above, all SIP messaging is encrypted on unsecure side of SBC (TLS) and unencrypted on secure side of SBC. At step 202 , the Bridge Interface Layer 12 returns a 407 Proxy-Authentication Required response and includes a challenge for authentication (includes specifics for method of Authentication). At step 203 , the customer UA 22 provides an ACK 407 response and then at step 204 the UA 22 re-sends INVITE plus the authentication challenge response, which in one embodiment may be an MD5 hash of various data including username and password.
At step 205 , the authentication response is validated via a transaction to user DB 19 to find username and password, and if valid, route INVITE on to next hop. In the present case, at step 206 , the call routes to an audio conference bridge locally, but could be to some other entity such as another registered user or to some other site. At step 207 , the audio conference bridge 24 replies to the Bridge Interface Layer 12 with 200 OK indicating INVITE request was accepted. At step 208 , the Bridge Interface Layer 12 replies to user 22 with 200 OK indicating INVITE request was accepted. At step 209 , RTP Media is setup between user end-point 22 and audio conferencing bridge 24 (via SBC 28 , but not Bridge Interface Layer 12 . RTP may be encrypted on unsecure side of SBC (SRTP) 28 and unencrypted on secure side of SBC 28 .
In one embodiment, internet softphone 22 may be configured to provide parameters of an audio conference in the SIP Invite. The Bridge Interface Layer 12 or the audio conferencing bridge 24 may be configured to extract these parameters from the SIP Invite, rather than through a DTMF prompts as would be typical for a standard telephone interaction.
In one embodiment, the parameters may be provided in one or more X-header fields of the transaction used to define the SIP Invite. For example, the internet softphone 22 may be configured to provide a passcode for an audio conference into an X-header field of the SIP INVITE transaction. The Bridge Interface Layer 12 or the audio conferencing bridge 24 may be configured to receive the SIP Invite and extract the passcode from the appropriate x-header field. If the passcode is valid, the internet softphone 22 can be validly connected to the audio conference, routed to another SIP endpoint or otherwise turned away. Sending the passcode as an X-Header as part of the SIP Invite means that the leader or participant does not need to manually enter the passcode using DTMF digits.
Other parameters of the audio conferencing set-up that may be provided in an X-header field may include, without limitation:
Is Host—An X-header to identify whether a person joining a call is a leader or participant.
Leader Pin—Sending the Leader Pin as an X-Header as part of the SIP Invite means that the Leader does not need to manually enter the Leader Pin using DTMF digits.
Security Code/Phone PAC—These two parameters may be sent as X-Headers in the SIP Invite to set the Security Code or Project Accounting Code for a call without needing to manually enter them via DTMF. A softphone based collection method is required to collect this information from the Leader (and participants in the case of Security Code). This collection mechanism can take the form of a keypad UI or some other text input UI provided as part of the internet softphone software.
Attendee ID—Sending a unique ID as an X-Header in the SIP Invite to allow synchronization between an audio conference and web based conference. Sending this in an X-Header means that the conference participant does not need to manually enter this information via DTMF.
For all these X-Header use cases, it is the softphone 22 which sends the X-Header and the Bridge Interface Layer 12 or the audio conference bridge 24 which interprets the X-Header. Other elements that may be between the softphone 22 and the Bridge Interface Layer 12 or audio conferencing bridge (typically a Session Border Controller) will transparently pass the SIP Invite with X-headers on unchanged.
As an alternative to providing the audio conference parameters in an x-header of the SIP Invite, one or more of the audio conference parameters may be provided in a URI.
Encryption may be required as part of SIP Registration and Proxy Service. The SBC 28 processes encryption verification on unsecure side, and allows for non-encrypted communication on secure side. Encryption may be applied to both SIP messaging (Secure SIP using TLS with Signed Certificates) and RTP Media (SRTP). SIP messaging may include both REGISTER events and INVITE call-flows. Each SBC open to Internet SIP traffic would need individual certificate, e.g. based on assigned IP and/or domain. SBC may handle the communication between Certificate Authority for gathering of public keys for inbound calls from encrypted sources.
The main reason for Proxy and Registration Authentication is to validate that an incoming call or register event is coming from a valid user of the proprietary audio conferencing services. That is, callers that are not valid users should be rejected. In general, calls received at the Bridge Interface Layer from an authorized SIP client will be valid. Calls from other stand-alone clients may be valid, but will need unique Authentication credentials to be established before the call is allowed to complete.
The authentication process may be approached in several ways. In one embodiment, it can be deemed necessary to know the individual identity of every caller that reaches the bridge network (i.e. an entry for each user). In an alternative embodiment, it may be sufficient to know that the caller is reaching the network using an approved SIP phone. In this case, i.e. where it is not necessary to know the identity of each caller it may be possible to use generic Authentication credentials that can be shared amongst multiple users.
Below are a few possibilities that could be used for the Authentication credentials when a SIP call attempts to reach the bridge platform.
In a first authentication embodiment, a random, unique username/password is created when the SIP client is installed on the end-user PC (i.e. customer softphone 22 ). This would not change but instead is hard-set per install. The end-user may be allowed to setup the username/password (part of install process), or the credentials could be generated randomly or logically by the service provider. Once generated, the credentials are loaded into the client as well as stored in the Authentication database. When the client connects (REGISTER or INVITE), a challenge is issued and the client returns hashed values for username/password, e.g. using the MD5 or Digest method. The user would not need to configure anything on their end, and auth entry would be hidden from user.
In a second authentication embodiment, a set of usernames/passwords may be created for each passcode provisioned in the audio conferencing database with IP calling privileges. Example—If trying to join a conference using passcode 123456789, the username/password for participant 1 may be 123456789/001. The Auth credentials would be dynamically allocated to client per call. This would require some connection back to the service provider to retrieve the username/password. When the client connects (REGISTER or INVITE), the authentication challenge is issued and with the client returning hashed values for username/password. The user would not need to configure anything on their end, and entry would be hidden from user.
In a third authentication embodiment, a random username/password may be assigned to each user as they attempt to join a conference from the SIP client. The Authentication credentials would be dynamically allocated to client per call. Like the methods above, this process may require a separate method such as a Call Control API (CCAPI) to retrieve the assigned username/password as the client initially attempts to connect. Dynamically assigning random username/password to the Authentication DB may require the service provider to de-register each end-point at the end of the call. In this embodiment, only active callers would have entries in the DB. A mechanism to remove valid auth entries once calls complete would be required.
If individual identity of each caller is not required, then in a fourth authentication embodiment, a single username/password combination can be created for each passcode provisioned in the audio conferencing bridge database with IP calling privileges. All callers to the passcode would use same username and password combination to connect. This would require some connection back to the service provider to retrieve the username/password.
In a fifth authentication embodiment, the same random username/password is assigned to all users as they attempt to join any conference from the SIP client. The username/password combination could be left static, or changed periodically based on security concerns. This process would require a method to retrieve the assigned username/password before or during the client's initial attempt to connect. However, a mechanism to change auth entry in auth proxy DB at regular intervals would be required.
When the Bridge Interface Layer or audio conferencing bridge receives the passcode of the conference that the client wishes to join, routing logic can be built so that the calls are routed to the correct site/SIP server. A separate method such as CCAPI will send DNIS and destination IP information to the client.
When a call participant wishes to join an audio conference, they initialize their installed SIP client. Initialization may be automated as part of a larger client, such as a WebEx or InterCall web client, or may be a standalone softphone. As part of that initialization a connection to CCAPI (or similar web service) is made to retrieve parameters relevant to the softphone, based on the passcode. CCAPI will return relevant parameters to the client including, but not limited to, the Authentication credentials, the SIP URI, codec selection, passcode, security code and account code settings. When the participant chooses to join a conference, the relevant parameters are mapped into SIP URI and custom SIP X-headers in a SIP Invite. Such parameters may include, but are not limited to, the conference passcode, participant role, web-conference synchronisation, Security code, account code. In general, conference information is passed from the softphone client to the Bridge Interface Layer and audio conferencing bridge via X-headers and without requiring user input, though this is not a strict requirement depending on the features enabled in a conference.
When a conference host wishes to join a conference, they initialize their installed SIP client. Initialization may be automated as part of a larger client, such as a WebEx or InterCall web client, or may be a standalone softphone. As part of that initialization, a connection to CCAPI (or similar web service) is made to retrieve parameters relevant to the softphone, based on the passcode. The CCAPI will return relevant parameters to the client including, but not limited to, Authentication credentials, the SIP URI, codec selection, passcode, Security code and Account code settings. When the host chooses to join a conference, the relevant parameters are mapped into SIP URI and custom SIP X-headers in a SIP Invite. Such parameters may include, but are not limited to, the conference passcode, participant role, leader PIN, web-conference synchronisation, Security code, account code. In general, conference information is passed from the softphone client to the InterCall conference bridge via X-headers and without requiring user input, though this is not a strict requirement depending on the features enabled in a conference.
CCAPI may also be used for in-conference control (mute, record, etc.) via the client, if desired.
The above described embodiments allow internet softphone users to register with a Bridge Interface Layer (where the Bridge Interface Layer can be defined as a server that can accept REGISTER and INVITE messages from Internet sourced IPs), and subsequently place call to audio conference bridge numbers using SIP. Calls may be encrypted on the Internet side (from end-user to the network edge/Session Border Controller (SBC)), and Authentication will be used to identify specific callers as they reach the network (performed within the Bridge Interface Layer).
An audio conference bridge that is configured to read parameters of an audio conference from a SIP Invite message may be used to facilitate other intelligent aspects of audio conference processing and call routing. In one embodiment, the audio conference bridge may be employed for referring misdirected calls from internet softphones. A system for REFER is depicted in FIG. 3 .
In this case, at step 301 , a user dials a number in the user interface of the internet softphone 22 . In the present example, the dialed number is “1234”. At step 302 , a SIP Invite is passed from the internet softphone 22 through internet 26 and ultimately to the audio conferencing bridge 24 following the SIP Invite procedure described above (steps 303 to 307 ), thereby establishing an RTP media stream (step 308 ). Bridge 24 accepts the call and extracts the Passcode from the SIP Invite. Bridge is configured to process the Passcode and is able to determine that in this example, the passcode is homed on bridge 25 in Data Center 2 (step 309 ). The bridge 24 sends a REFER back to caller UA (steps 310 to 312 ) with referred-by header. The UA 22 is configured to accept the REFER and generate a new INVITE to the SBC for Data Center 2 (steps 313 to 315 ). The new INVITE may include the passcode in an x-header as described above. Bridge 25 accepts the new SIP Invite and (based on referred-by info) is able to place the caller into conference without having to re-prompt for passcode (step 316 ). 200-OK messages are returned to the caller (steps 317 to 319 ). RTP is torn down between the UA and the bridge 24 and re-established direct from UA to Bridge 25 (step 320 )(no MPLS bandwidth used).
In addition to the enhanced functionality provided by the audio conferencing bridge, other aspects of the SIP system may be configured for enhanced audio conference bridge processing and call routing.
FIG. 4 shows a distributed architecture and a process for redirecting SIP Invites based on Dialed Number Identification Service (DNIS). The process of sending the SIP Invite from the internet softphone to the audio conferencing bridge 24 (steps 401 to 404 ) are the same as for the process shown in FIG. 3 . In this case, the dialed number (in To: SIP URI) is “1234”. When bridge 24 does a lookup of the DNIS (step 405 ), it sees that the DNIS is assigned to bridge 26 in Data Center 2 , and sends back a 302 message with sip2.intercall.com (10.28.162.100) in contact field (step 406 ). Some entity (in this case the Bridge Interface Layer 12 in Data Center 1 ) processes the 302 Redirect and sends INVITE to sip2.intercall.com with new contact info (step 407 ) via the Multiprotocol Label Switching (MPLS) backbone 40 and Bridge Interface Layer 42 in Data Center 2 . Bridge 25 receives the SIP INVITE (step 408 ), and since the dialed number is assigned to bridge 25 (look up step 409 ), it sends a 200 OK message indicating call is accepted (step 410 ) which is returned to the internet softphone 22 via the Bridge Interface Layer 42 and Bridge Interface Layer 12 .
RTP is setup between internet softphone 22 and audio conference bridge 25 through Data Center 1 SBC 28 , then traverses MPLS backbone 40 to Data Center 2 audio conferencing bridge 25 (step 414 ). In an alternative embodiment, the 302 Redirect message may be returned all the way back to the calling UA (softphone or Proxy server) so that the INVITE could be sent direct to the redirected site (bridge 25 ) and then RTP is setup direct from UA to the new site (bridge 25 ) via the SBC 48 of the new site.
One instance where a redirect may be required is where an audio conference has been moved, either temporarily or permanently, from one bridge to another for load balancing reasons.
FIG. 5 shows an alternate distributed architecture. In this embodiment, the call routing is performed by the Bridge Interface Layer 12 and is based on information in the SIP Invite including X-headers. For example, the call routing decision may be based on the SIP URI, the passcode, or some other piece of information in the SIP Invite. The process of sending the SIP Invite from the internet softphone to the Bridge Interface Layer 12 (steps 501 to 503 ) is the same as for the process shown in FIG. 3 . In this case, the dialed number (in To: SIP URI) is “1234”. When the Bridge Interface Layer 12 does a lookup of the information contained in the SIP Invite ( 504 ) it sees that the conference should be hosted on audio conferencing bridge 25 in Data Center 2 . The Bridge Interface Layer sends a 302 Redirect ( 506 ) to the UA 22 with the IP Address or DNS name of Data Center 2 SBC 48 in the Contact header. The UA 22 initiates a new SIP Invite to Data Center 2 ( 507 - 508 ) where Bridge Interface Layer 42 confirms that the call is destined for Bridge 25 . Bridge 25 receives the SIP INVITE (step 510 ), and since the dialed number is assigned to bridge 25 (look up step 511 ), it sends a 200 OK message indicating call is accepted (step 512 ) which is returned to the internet softphone 22 via the Bridge Interface Layer 42 .
RTP is setup between internet softphone 22 and audio conference bridge 25 through Data Center 2 SBC 48 .
In the system depicted in FIG. 6 , load balancing may be performed between multiple bridges 24 , 25 by a Domain Name System (DNS) server 51 . The bridges 24 , 25 are each uniquely identified by a domain name that is registered with the DNS Server 51 . The multi-bridge system is setup with two or more possible routes within DNS server 51 for sip.serviceprovider.com. In the present example 53, the primary route may be sip1.serviceprovider.com (IP is 10.72.196.100 assigned to SBC in Data Center 1 ), and backup may be sip2.serviceprovider.com (10.28.162.100 in Data Center 2 ).
In this case, user dials 1234@sip.serviceprovider.com (step 601 ) and the DNS Server 51 tries to resolve sip.serviceprovider.com (step 602 ). The DNS server 51 returns dialed number (in To: SIP URI) “1234” (step 603 ) and a corresponding SIP INVITE is sent toward bridge 215 (steps 604 to 606 ). When bridge 24 app server does lookup of DNIS, it sees that DNIS is assigned to bridge 24 and 200 OKs the INVITE (steps 607 to 609 ). RTP is setup between UA and bridge 24 (via SBC 28 ) (step 610 ).
If the SIP INVITE to the primary bridge 24 gets no response within a configurable and pre-set time limit, the UA 22 would then send the SIP INVITE to backup bridge 25 via SBC 48 .
Various load balancing strategies may be employed. For example, the DNS server 51 could be set so that the two priorities for the two entries are the same and/or a bridge could be chosen based on various current or historical usage criteria. Additional entries for other connected sites could also be include. These may include, without limitation: Language Requirements, maintenance or other administration requirements, hot-standby/failover or load-balancing, or historical usage patterns.
The components of the system may be embodied in hardware, software, firmware or a combination of hardware, software and/or firmware. In a hardware embodiment, administration module may be executed on one or more processors operatively associated with one or more memories. The memory may store instructions that are executable on the processor to perform the methods and techniques described herein.
Although embodiments of the present invention have been illustrated in the accompanied drawings and described in the foregoing description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the spirit of the invention as set forth and defined by the following claims. For example, the capabilities of the invention can be performed fully and/or partially by one or more of the blocks, modules, processors or memories. Also, these capabilities may be performed in the current manner or in a distributed manner and on, or via, any device able to provide and/or receive information. Further, although depicted in a particular manner, various modules or blocks may be repositioned without departing from the scope of the current invention. Still further, although depicted in a particular manner, a greater or lesser number of modules and connections can be utilized with the present invention in order to accomplish the present invention, to provide additional known features to the present invention, and/or to make the present invention more efficient. Also, the information sent between various modules can be sent between the modules via at least one of a data network, the Internet, an Internet Protocol network, a wireless source, and a wired source and via plurality of protocols. | To enable load balancing and the like for audio conferencing systems of an audio conferencing network, a DNS server may receive a DNS lookup from an internet softphone and return a prioritized list of audio conferencing system identities. The internet softphone may select an audio conferencing system and forward a SIP Invite to a Bridge interface layer of the respective audio conferencing system. If the SIP Invite does not generate a successful connection or generates a timeout, the internet softphone forwards the SIP Invite to the next prioritized Bridge interface layer in the list. | 7 |
This application is a division of application Ser. No. 07/994,523 filed Dec. 21, 1992, now abandoned, which in turn is a division of application Ser. No. 07/834,999 filed Feb. 14, 1992, now U.S. Pat. No. 5,202,702, which in turn is a continuation of application Ser. No. 07/746,214 filed Aug. 16, 1991, now abandoned, which in turn is a continuation of application Ser. No. 07/598,778 filed Oct. 18, 1990, now abandoned, which in turn is a continuation of application Ser. No. 07/449,411 filed Dec. 18, 1989, now abandoned, which in turn is a continuation of application Ser. No. 07/267,632 filed Oct. 31, 1988, now abandoned, which in turn is a continuation of application Ser. No. 06/846,887 filed Apr. 1, 1986 now abandoned. SPECIFICATION TO ALL WHOM IT MAY CONCERN:
Be it known that we, KOJI TERASAWA, AKIRA MIYAKAWA and HIDEKI YAMAGUCHI, subjects of Japan, residing at 9-5-103, Shimorenjaku 9-chome, Mitaka-shi, Tokyo, Japan, 2-10, Shibakubo 2-chome, Tanashi-shi, Tokyo, Japan and 33-7, Aobadai 2-chome, Midori-ku, Yokohama-shi, Kanagawa-ken, Japan, have jointly invented a certain new and useful improvement in AN INK JET RECORDING APPARATUS AND A METHOD OF CLEANING A RECORDING HEAD USED IN THE APPARATUS of which the following is a full, clear, concise and exact description.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an ink jet recording apparatus having a cleaning mechanism for cleaning a surface in which an ink discharge port is provided (the front surface of a recording head) and to a method of cleaning the recording head used in the apparatus.
2. Related Background Art
In ink jet recording apparatuses, paper powder, dust or ink of increased viscosity may adhere to a surface in which is provided the ink discharge port of a recording head installed on a carriage movable along recording paper, and the ink discharge port may be clogged thereby causing unsatisfactory ink discharge. Heretofore, it has been practised to provide cleaning means in order to remove these foreign materials.
A mechanism for wiping the ink discharge port surface of the recording head by a flexible blade may be adopted as such cleaning means.
Also, in ink jet recording apparatuses, in order to prevent the ink discharge port from being clogged by ink of increased viscosity resulting from evaporation of ink solvent, or adherence of dust, or bubbles caused by gases remaining after solution, capping means for capping the ink discharge port surface of the recording head and ink discharge recovery means for effecting idle discharge of ink may be adopted. The capping operation and the ink discharge recovery operation by these means, respectively, are usually performed when the carriage mounting the recording head thereon is in its home position.
However, in the ink jet recording apparatus according to the prior art, the operation of cleaning said ink discharge port surface is independent of said capping operation and said ink discharge recovery operation and thus, requires a drive source exclusively for cleaning and is performed in a discrete sequence, and this has led to structural complexity and increased cost.
Also, even in a case where a mechanism for wiping the front surface of the recording head by a flexible blade made of a plastic sheet or the like is adopted as cleaning means, the cleaning operation by said blade is performed as an independent operation and an exclusive drive source (motor) is required for the driving of the blade, and this has also led to structural complexity and bulkiness as well as increased cost.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an ink jet recording apparatus which solves the above-noted problems peculiar to the prior art.
It is another object of the present invention to provide an ink jet recording apparatus which does not require a drive source for exclusive use and in which the front surface of the recording head, i.e., the ink discharge port surface, can be wiped by a minimum mechanism.
In accordance with one aspect of the invention, an ink jet apparatus comprises a recovery device for performing a recovery operation on an ink jet head to recover a discharge condition thereof and a test print mechanism for conducting a test print using the ink jet head.
In accordance with another aspect of the invention, a recording method for an ink jet apparatus comprises the steps of performing a recovery operation on an ink jet head to recovery a discharge condition thereof and conducting a test print using the ink jet head.
It is a further object of the present invention to provide an ink jet recording apparatus and a cleaning method which do not require any new cleaning mechanism and any special sequence or the like and in which the ink discharge port surface can be wiped always by a clean blade.
It is still a further object of the present invention to provide an ink jet recording apparatus and a cleaning method in which the direction of wiping by the blade is set to one direction, whereby dust is not forced into the ink discharge ports and cleaning of the ink discharge port surface can be accomplished reliably.
It is also an object of the present invention to provide a method of cleaning an ink jet recording head characterized in that a flexible blade is moved forwardly and backwardly in response to the capping operation of the front surface of the recording head and the movement of a carriage and the front surface of the recording head is wiped by said blade in response to the movement of said carriage.
It is another object of the present invention to provide an ink jet recording apparatus having a recording head disposed on a carriage, cap means for covering the front surface of said recording head and a blade for cleaning the front surface of said recording head, and further having blade moving means for moving said blade forward or backward in the direction of said recording head in response to the movement of said cap means and the movement of said carriage.
It is still another object of the present invention to provide a method of cleaning an ink jet recording head wherein when the front surface of said recording head is wiped by a flexible blade with the aid of the movement of a carriage mounting said recording head thereon, the direction of wiping of said blade is only one direction.
In addition, it is an object of the present invention to provide an ink jet recording apparatus having first moving means for moving a flexible blade in its received position to a cleaning position to clean the front surface of a recording head, carriage moving means for moving a carriage mounting said recording head thereon in one direction to clean said recording head when said blade is in the cleaning position, and second moving means for moving said blade from the cleaning position to said received position when the carriage is moved in a direction opposite to said one direction.
It is also an object of the present invention to provide a method of cleaning an ink jet recording head characterized in that when the front surface of said recording head is to be wiped by a flexible blade with the aid of the movement of a carriage mounting said recording head thereon, said blade is wiped by the movement of said carriage, whereafter the front surface of said recording head is wiped by said blade.
In addition, it is an object of the present invention to provide an ink jet recording apparatus having a recording head for discharging liquid and forming flying liquid droplets, a carriage having said recording head mounted thereon, a flexible blade for cleaning the surface of said recording head in which a discharge port is disposed, and a cleaning member provided to clean said blade.
It is another object of the present invention to provide an ink jet recording apparatus characterized by a flexible blade, a movable carriage mounting a recording head thereon, means for moving said carriage and causing said flexible blade to wipe the front surface of said recording head, and means for effecting pre-discharging or pre-heating of ink by electro-thermal energy converting members provided in said recording head after the front surface of said recording head is wiped.
It is still another object of the present invention to provide an ink jet recording apparatus having a recording head, a flexible blade, ink discharge recovery means, and operation control means for controlling both of the operation for cleaning the front surface of said recording head by said flexible blade and the ink discharge recovery operation by said ink discharge recovery means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 3 are schematic plan views showing the essential portions of an ink jet recording apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view of the ink discharge recovery device of FIG. 1.
FIG. 4 is a flow chart showing an example of the operation sequence of the apparatus of FIG. 1.
FIG. 5 is a flow chart showing another example of the operation sequence of the apparatus of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention will hereinafter be specifically described with reference to the drawings.
FIG. 1 shows the construction of the essential portions of an ink jet recording apparatus according to an embodiment of the present invention.
Referring to FIG. 1, a guide shaft 3 is installed forwardly of recording paper 2 backed up by a platen 1, and a recording head 5 movable along the guide shaft is mounted on a carriage 4.
An ink discharge recovery device 6 (which, in the example shown, is of the pump suction type) is provided at the home position HP of the carriage (at the left side of the platen 1 as viewed in FIG. 1). The ink discharge recovery device 6 is provided with capping means 7 driven forwardly and backwardly relative to the recording head 5 and hermetically sealing the front surface of the recording head (the surface formed with an ink discharge port) at the forwardly moved position, and a pump 9 driven by a suction operation lever 8 and sucking ink from the discharge port through capping means 7.
A flexible blade 10 for wiping the front surface of the recording head 5 is mounted on a side (the right side as viewed in FIG. 1) of the capping means 7. This blade 10 is moved forwardly with the forward movement of the capping means 7 which is accomplished by transmitting the drive of a motor or the like thereto by the use of a cam or the like, and during the backward movement of the capping means, it is mounted on the capping means by a mechanism adapted to be left restrained at its forwardly moved position. The backward movement of the blade 10 may be accomplished by releasing the restrained state by the movement of the carriage 4 when the carriage passes from right to left.
FIG. 2 illustrates the structure of the ink discharge recovery device 6.
Referring to FIG. 2, the suction operation lever 8, the pump 9 driven by depression of the lever 8, and the capping means 7 are supported on a bed 11, and the capping means is supported for forward and backward movement.
A blade supporting plate 12 is mounted on the right side of the capping means 7 while being biased backwardly by means of a slot 13, a stop pin 14 and a backwardly biasing spring 15, and the flexible blade 10 comprising a plastic sheet or a rubber sheet is attached to the fore end portion of the blade supporting plate 12. An engaging member 17, having a pivotable type fitting portion biased to a position engageable with the supporting plate 12 by a spring 16, is attached to the bed 11. This engaging member 17 is adapted to be pivoted (depressed) in the direction of arrow B when the carriage 4 (or the projection thereof) strikes against the inclined surface at the end of the engaging member 17.
A switch (not shown) is connected to the suction operation lever 8, and the circuit construction is such that the switch is closed by the suction operation lever 8 being once depressed and when this is detected, the wiping of the recording head 5 by the blade 10 is effected and the normal ink discharge recovery operation is effected by the suction operation lever being depressed once more.
The operation of the above-described construction will now be described with reference to FIG. 1.
When the carriage 4 is moved from right to left and comes to the home position HP, the capping means 7 moves forward and closes the front of the recording head 5. That is, the cap closing operation is automatically effected. At this time, the blade 10 also moves forward.
The suction operation lever 8 is then pushed to effect an ink discharge recovery operation (an ink suction operation) and, when the ink suction operation is completed, the capping means 7 moves backward. At this time, the blade 10 is still left in its forwardly moved position.
The carriage 4 is then moved leftwardly from the home position HP and at this time, the engaging member 17 (FIG. 2) is depressed and the blade 10 moves backward.
The carriage 4 is then moved rightwardly from its leftmost position and passes the home position HP and is stopped at a position spaced rightwardly from the home position by a predetermined distance.
Thereupon, the capping means 7 is moved forwardly to thereby move the blade 10 forward, and then the capping means is moved backwardly. At this time, the blade 10 is left in its forwardly moved position.
Subsequently, the carriage 4 is moved leftwardly and driven to its leftmost position past the home position HP. In this case, before the carriage arrives at the home position HP, the front surface of the recording head 5, i.e., the surface thereof provided with an ink discharge port, is first wiped by the blade 10 to clean the discharging surface, and then the carriage 4 or the projection thereof strikes against the engaging member 17 (FIG. 2) to move the blade 10 backward while the carriage is further moved leftwardly from the home position HP.
Thereafter, the carriage 4 is moved rightwardly and in the ordinary case, test print is effected and subsequently, an ordinary printing operation in which printing is started by a printing signal is effected.
According to the embodiment described above, the blade 10 is driven forwardly and backwardly by the movement of the capping means 7 and the movement of the carriage 4 and the front surface of the recording head 5 is wiped by the blade utilizing the movement of the carriage 4, and therefore no drive source for exclusive use is required but the cleaning of the ink discharge port surface by the blade 10 can be accomplished by the utilization of the existing mechanism.
Thus, the device for wiping the recording head 5 can be inexpensively constructed by a very simple and compact mechanism.
In the foregoing description, the wiping by the blade 10 has been effected once, but if required, a sequence in which the wiping is repeated twice or more often can be freely carried out.
Also, the direction in which the front surface of the recording head is wiped by the blade 10 may be set to only a direction in which the carriage 4 is moved leftwardly, namely, one direction.
Again in this case, the carriage 4 is moved rightwardly after the completion of the cleaning by the blade 10, and in the ordinary case, test print is effected and subsequently, a normal printing operation in which printing is started by a printing signal is effected.
Usually, in the printing operation from the capped condition, the carriage 4 is moved leftwardly and the blade 10 is moved backwardly, whereafter printing is effected and therefore, the recording head 5 does not contact the blade 10.
As described above, design is made such that the front surface of the recording head 5 can be wiped by the blade 10 only when the carriage 4 is moved from right to left, whereby the direction in which the front surface of the recording head is wiped by the blade 10 is set to one direction and therefore, it never happens that, as in the prior art, the dust pushed away in one direction is forced into the ink discharge port while it is again pushed away in the other direction, and thus, cleaning of the ink discharge port can be reliably accomplished.
In the foregoing description, the wiping operation of the blade 10 has been completed by one operation, but again in the case of the cleaning in one direction, if required, the wiping operation can be freely set to twice or a greater desired frequency by suitably modifying the sequence.
Also, in the embodiment shown, the blade 10 is driven forwardly and backwardly when the ink discharge port surface is wiped, but alternatively, design may be such that the recording head 5 is driven forwardly and backwardly.
Further, the wiping operation by the blade may be effected at any time independently of the capping operation.
In the present invention, when the front surface (the ink discharge port surface) of the recording head 5 is to be wiped, the blade 10 may first be wiped by the movement of the carriage 4, whereafter the front surface of the recording head may be wiped by the blade 10.
FIG. 3 shows a state in which the blade 10 is wiped by the movement of the carriage 4.
In this state, as previously described, the capping means 7 is in its backwardly moved position and the blade 10 is in its forwardly moved position.
On the opposite sides (or only on the left side as viewed in FIG. 3) of the recording head 5, there are provided protrusions 20 which utilize a portion of the carriage 4 or of a head holder 19 holding the recording head to slidably contact and wipe the blade 10 by movement of the carriage 4 (in the direction of arrow A).
Thus, by movement of the carriage 4, the protrusion 20 wipes and clean the surface of the blade 10, whereafter the blade wipes the front surface of the recording head 5, namely, the surface thereof formed with an ink discharge port.
The portion of the carriage 4 for wiping the blade 10 which portion corresponds to the protrusion may be provided at any other location on the carriage 4 than the surface formed with the ink discharge port.
According to the embodiment described above, even if any special mechanism for cleaning the blade 10 is not provided, the blade 10 can be cleaned by the utilization of the movement of the carriage 4.
Also, the blade 10 can be cleaned without fail before the recording head 5 is wiped and therefore, the ink discharge port can always be cleaned effectively.
Further, any special sequence for cleaning the blade 10 is not required, but cleaning of the blade 10 can be realized simply by providing the protrusions (the sliding contact portions) 20 on the carriage side.
In the embodiment shown, description has been made of a case where the front surface of the recording head 5 is wiped only when the carriage 4 is moved from right to left, that is, only from one direction, but the present invention is equally applicable also to the case of cleaning means of the type which wipes the recording head 5 from the opposite direction or from both directions.
Description will hereinafter be made by taking as the recording head 5 an example using a system wherein a plurality of electro-thermal energy converting members (heat generating elements) corresponding to a plurality of ink discharge ports are driven on the basis of a printing signal and the generated heat energy is utilized to form flying ink droplets. In the recording head 5, in addition to the electro-thermal energy converting members for printing drive as mentioned previously, there are provided in some cases electro-thermal energy converting members (pre-heating heaters or the like) for heating the atmospheric temperature to bring about a printable condition when the atmospheric temperature is low and viscosity of ink is high, and the electro-thermal energy converting members in the present invention refer to one or both of these energy converting members.
FIGS. 4 and 5 are flow charts illustrating the sequence of the blade wiping operation by the operation control means of the above-described ink jet recording apparatus.
The sequence of FIG. 4 will first be described with reference to FIGS. 1 and 2.
Step 101: The carriage 4 is moved from right to left and arrives at the home position HP, whereupon the movement thereof is stopped and then the capping means 7 is moved forwardly and closes the front surface (ink discharge port surface) of the recording head 5. At this time, the blade 10 is also moved forward. (The carriage is in the home position.)
Step 102: The suction operation lever 8 of the discharge recovery device is pushed to thereby effect the ink discharge recovery operation. At the same time, the contact making for effecting the wiping operation by the blade is effected by the lever 8. (For example, the pressure force thereof is detected by a switch and the contact making is effected.) (The carriage is in the home position.)
Step 103: When the suction operation is completed, the flicker of LED as an operation signal is completed and the capping means 7 is moved backwardly. The blade 10 is left in its forwardly moved position by the leaving mechanism. (The carriage is in the home position.)
Step 104: Subsequently to the contact making at step 102, LF (line feed) switch is closed.
Step 105: The carriage 4 is moved leftwardly from the home position HP, whereby the engaging member 17 is depressed and the blade 10 is moved backwardly. (The carriage is at the left of the home position.)
Step 106: The carriage is moved rightwardly and is stopped at a position spaced rightwardly from the home position by a predetermined distance. (Since the blade is moved backwardly, the wiping (cleaning) operation by the blade is not performed.)
Step 107: The capping means 7 is moved forwardly, whereby the blade 10 is also moved forwardly. (Since the carriage is at the right of the home position, the front of the recording head 5 is not closed.)
Step 108: The capping means 7 is moved backwardly. The blade 10 is left at its forwardly moved position by the leaving mechanism. (The carriage is at the right of the home position.)
Step 109: The carriage 4 is moved leftwardly to the home position. The front surface of the recording head 5 is wiped by the blade 10 while the carriage is thus moved. (The blade is moving forward.)
Step 110: The electro-thermal energy converting members provided in the recording head 5 are driven by transmitting a signal processed in control means 35 in accordance with a pre-discharge signal 33 or a pre-heat signal 34 through flexible wiring 36 to effect the pre-discharging or pre-heating of the ink in the vicinity of the ink discharge ports, thereby reducing the viscosity of the ink near the ink discharge ports. (The carriage is in its home position and the blade is in its forwardly moved position.)
Step 111: The carriage 4 is moved leftwardly from the home position HP, whereby the engaging member 17 is depressed and the blade 10 is moved backwardly. (The carriage is at the left of the home position.)
Step 112: The carriage 4 is moved to the right printing starting position and test print is effected. By this time, the blade 10 has already been moved backwardly and therefore, the front surface of the recording head 5 is not wiped by the blade 10.
Thereafter, the normal printing operation based on a printing signal is started.
At step 104, the LF switch may be replaced by other switch which need not be a special external switch. This step is not always necessary if a recording member is already prepared or if a pre-discharge position is provided discretely.
Further, normal printing may be effected on the basis of a printing command without the test print of step 112 being effected.
According to the above-described embodiment, the wiping of the ink discharge port surface of the recording head 5 by the blade 10 is carried out within the operation sequence of the ink discharge recovery operation and the operation of these is effected in a series by the contact making which starts the ink discharge recovery operation and therefore, the wiping operation and the control system therefor can be much simplified. Also, the influence upon the ink discharge ports can be reduced.
Furthermore, the wiping operation of the blade is accomplished by the utilization of the movement of the carriage 4, and this eliminates the necessity of providing a special drive source, which in turn leads to the provision of simple and inexpensive ink discharge port cleaning means.
The sequence of FIG. 5 of the control means will now be described with reference to FIGS. 1 and 2.
Step 201: When the carriage 4 is moved from right (for example, the printing area or the printing starting position) to left and arrives at the home position HP, this movement is stopped, and then the capping means 7 moves forward and closes the front (ink discharge ports) of the recording head 5. At this time, the blade 10 also moves forward with the capping means 7.
Step 202: The suction operation lever 8 is pushed to effect the ink discharge recovery operation and the switch is closed (the first contact making), and the contact making is detected, whereby starting a series of operations for wiping the front surface of the recording head 5, i.e., the surface formed with the discharge ports, by the blade 10.
Step 203: The capping means 7 is moved backwardly from the recording head 5 to open the cap. At this time, the blade 10 is left in its forwardly moved position. The carriage is in its home position.
Step 204: The carriage 4 is moved leftwardly from the home position HP to thereby depress the engaging member 17, thus moving the blade 10 backward.
Step 205: The carriage is moved rightwardly from its leftmost position and passes the home position HP and is stopped at the right thereof. Since the blade 10 has already been moved backwardly, the front surface of the recording head 5 is not wiped.
Step 206: The capping means 7 is moved forwardly and the blade 10 is also moved forwardly. The carriage is not moved from the right of the home position.
Step 207: The capping means 7 is moved backwardly. The blade 10 is left in its forwardly moved position by the leaving mechanism.
Step 208: The carriage 4 is moved leftwardly to the home position HP, whereby the ink discharge port surface of the recording head 5 is wiped by the blade 10 (blade cleaning).
Step 209: The capping means 7 is moved forwardly and closes the ink discharge port surface of the recording head which is now in the home position.
Step 210: The suction operation lever 8 is pushed to effect the second contact making (the contact making for the ink discharge recovery operation).
Step 211: The ink suction operation from the ink discharge ports is completed and the flicker of LED as the operating signal for the suction operation is completed.
Step 212: The electro-thermal energy converting members of the recording head 5 are driven by transmitting a signal processed in control means 35 in accordance with a pre-discharge signal 33 or a pre-heat signal 34 through flexible wiring 36 to effect the pre-discharging or pre-heating of the ink in the vicinity of the ink discharge ports for reducing the viscosity of the ink, whereafter the capping means 7 is moved backwardly and the cap becomes open. At this time, the blade 10 is left in its forwardly moved position by the leaving mechanism.
Step 213: The carriage 4 is moved leftwardly from the home position HP to thereby depress the engaging member 17 and move the blade 10 backward.
Step 214: The carriage 4 is moved to the printing starting position or the printing capable position, whereupon test print is effected. By this time, the blade 10 has already been moved backwardly and therefore, the wiping of the recording head 5 does not take place.
Thereafter, the normal printing operation is started on the basis of a printing signal.
According to each embodiment described above, the ink discharge port surface (the front surface of the recording head 5, is wiped by the blade 10, where-after pre-discharging or pre-heating of the ink discharge ports is effected by the heating means provided in the recording head and therefore, even if ink of increased viscosity adheres to the ink discharge ports when wiped by the blade, the recording head 5 can be heated to pre-discharge the ink of increased viscosity by the pre-discharging or reduce the viscosity of the ink to a proper value by the pre-heating and thus, it becomes possible to secure normal printing operation.
Also, the above-described operation can be carried out simply by the utilization of the existing heating means and therefore, it is not necessary to provide a new mechanism and proper viscosity of the ink can be realized by only modifiying a part of the sequence and by a very simple and inexpensive construction.
The present invention can be freely carried out in a suitable sequence as defined in the appended claims even if the operation control means and the sequence of the control means are other than those described above.
According to the present invention, as described above, there can be provided an ink jet recording apparatus which does not require a drive source for exclusive use and in which the front surface of the recording head, i.e., the ink discharge port surface, can be wiped by a minimum mechanism.
Also, according to the present invention, there can be provided an ink jet recording apparatus which uses the actuating (contact-making) means of the ink discharge recovery device and can execute the cleaning of the ink discharge port surface and the ink discharge recovery operation in a series of sequence and which permits omission of individual driving systems.
Further, according to the present invention, there can be provided an ink jet recording apparatus in which the ink discharge port surface can be cleaned by a simple operation and the ink discharging capability can be maintained normal.
Furthermore, according to the present invention, there can be provided an ink jet recording apparatus and a cleaning method which do not require any new cleaning mechanism and any special sequence or the like and in which the ink discharge port surface can be wiped always by a clean blade.
In addition, according to the present invention, there can be provided an ink jet recording apparatus and a cleaning method which can solve the problems peculiar to the prior art and in which the direction of wiping by the blade is set to one direction, whereby dust is not forced into the ink discharge ports and cleaning of the ink discharge port surface can be accomplished reliably. | A system using an ink jet recording head for scanning between a recording area and a non-recording area and for discharging ink to record an image on a recording medium at the recording area. The system includes wiping a discharge surface of the ink jet recording head, preliminarily discharging ink from the recording head after wiping, and performing normal recording in response to a recording signal without wiping the discharge surface of the ink jet recording head after the preliminary discharge. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to solvent-free or low-solvent coating compositions which harden to form polyurethanes and to the use thereof for the coating of substrates, in particular textiles.
2. Description of the Prior Art
The coating of textiles with polyurethane urea solutions containing up to 70%, by weight, of solvents is known. Either completely reacted polyurethane ureas or those which require a second component for subsequent crosslinking in order to achieve the coating properties thereof may be used for this purpose. Coating compositions of the last-mentioned type have been described, for example, in U.S. Pat. No. 3,711,571, according to which the dissolved polyurethane ureas are mixed with oxime-blocked isocyanate prepolymers and cured during a heat treatment in a drying channel. This method of coating has the disadvantage of requiring at least 50%, by weight, of solvents (not counting the quantity of blocking agent).
Other polyurethane urea coating compositions, which do not require solvent, have been disclosed in U.S. Pat. No. 3,755,261 and in German Offenlegungsschrift No. 2,462,317. These are thermosetting mixtures of liquid isocyanate prepolymers and a latent hardener based on salts of 4,4'-diaminodiphenylmethane ("MDA"). The latent hardener may be liquefied by suspending the MDA salt complex in at least 50%, by weight, of a PVC plasticizer of the phthalic acid ester type. According to the examples given, the isocyanate prepolymers contain a relatively high proportion of free diisocyanates.
Such a coating system has disadvantages in the physiological field. The relatively high free diisocyanate content and particularly the toxicity of MDA used as a constituent of the latent hardener are problematic. A further disadvantage of such coatings is the plasticizer content thereof. Due to "blooming" or "bleeding" of the plasticizer, dry top coats having perfect surfaces are unobtainable.
In British Pat. No. 970,459, there is described a process for bonding a foam foil to a textile substrate. The adhesive coating used is a reactive mixture consisting substantially of ketoxime-blocked isocyanate prepolymer and N,N,N',N'-tetrakis-(2-hydroxypropyl)-ethylene diamine as crosslinking agent. Since this system is cured via the urethane groups and not via urea groups, the end products are soft films which are not suitable for the production of top coats.
According to publication by J. Verhanik (publication of lectures held at the Congress of the Leather Industry, 18-22.10.78 in Budapest, pages 1279 to 1288, OMKDK-Technoinform 1428; Budapest Postbox 12) concerning a "thermoactive, solvent-free PUR system", polyether based isocyanate prepolymers which are blocked with phenol groups may be worked-up with polyether amines having molecular weights of approximately 750 to produce foam coatings. Apart from the toxic effect of the phenol blocking agent when released, this system has the disadvantage that it is restricted to a very narrow field of application on account of its mechanical properties.
It was, therefore, an object of the present invention to overcome the disadvantages mentioned above and provide a solvent-free or low solvent, physiologically harmless coating system which would fulfill the technical requirements of any coating component used, for example, for an adhesive coat, foam coat or top coat, including also a fusible top coat which may be welded.
This problem could be solved by using the coating composition described below.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to thermosetting two-component coating systems containing:
(A) a prepolymer having an average molecular weight of from about 1,000 to 15,000, preferably from about 2,000 to 8,000, having an average of from 2 to 4, preferably from 2 to 3, ketoxime-blocked aromatic isocyanate groups;
(B) a crosslinking agent corresponding to the following general formula: ##STR2## wherein R 1 to R 4 independently represent hydrogen or a C 1 -C 3 -alkyl group with the proviso that if R 1 to R 4 all represent hydrogen atoms, the diamine contains at least 75% of the cis,cis-isomer; and, optionally,
(C) pigments, fillers, blowing agents and other known additives;
wherein the equivalent ratio of blocked isocyanate groups to NH 2 groups is from about 1.35:1 to about 0.95:1, preferably from about 1.25:1 to about 1:1, and the coating compound contains not more than about 15% by weight, preferably not more than about 10% by weight of organic solvents and is free from aqueous polymer dispersions or polymer solutions such as those described in German Offenlegungsschrift No. 28 14 079.
The present invention also relates to a direct or reversal process for the coating of substrates with thermosetting two-component coating systems based on polyurethane, characterized in that the coating compounds according to the present invention are used as top coat, adhesive coat or foam coat.
DETAILED DESCRIPTION OF THE INVENTION
The isocyanates used for the synthesis of the ketoxime-blocked isocyanate prepolymers may be aromatic polyisocyanates, such as those described in detail in U.S. Pat. Nos. 3,984,607 and 4,035,213, German Offenlegungsschrift No. 2,402,840 and German Auslegeschrift No. 2,457,387. 2,4'- and 4,4'-diisocyanatodiphenylmethane, tolylene diisocyanate isomers and, in particular, mixtures of these diisocyanates are preferred according to the present invention.
Suitable reactants for these polyisocyanates to produce the isocyanate prepolymers include polyhydroxyl compounds having a molecular weight of from about 500 to 10,000, preferably from about 1,000 to 6,000, having from 2 to 8, preferably 2 or 3, hydroxyl groups, such as those described in detail in the above-mentioned publications.
The polyhydroxyl compounds preferably used according to the present invention include propylene oxide polyethers which have an average of from 2 to 3 hydroxyl groups and may also contain polyethylene oxide units as well as hydroxypolyesters having an average molecular weight of from about 1,000 to 6,000 which have 2 or 3 OH end groups and melt at temperatures below 60° C.
Particularly preferred according to the present invention are mixtures of the above-mentioned hydroxypolyethers with hydroxypolyester of adipic acid, hexane diol-(1,6) and neopentyl glycol having an average molecular weight of from about 1,000 to 3,000.
Low molecular weight polyols having a molecular weight of less than about 300, such as those known as crosslinking agents, may possibly also be used in the preparation of the isocyanate prepolymers. Among these low molecular weight polyols, those which are preferred according to the present invention include butane diol-(1,4) and trimethylol propane.
Preparation of the isocyanate prepolymers is carried out in known manner by reacting the above-mentioned polyhydroxyl compounds with excess diisocyanate, preferably at from about 70° to 110° C., generally using an NCO/OH ratio of from about 1.5:1 to 6.0:1, preferably from about 1.7:1 to 2.5:1.
Suitable blocking agents for the isocyanate prepolymers include, for example, ketoximes of hydroxylamine and ketones, such as acetone, methyl ethyl ketone, diethyl ketone, cyclohexanone, acetophenone and benzophenone.
A preferred blocking agent according to the present invention is methyl ethyl ketoxime (butanone oxime).
The blocking reaction is carried out by reacting the isocyanate prepolymer with stoichiometric quantities of ketoxime at elevated temperatures, e.g. at from about 70° to 100° C., until the isocyanate groups disappear.
The blocked isocyanate prepolymers may be mixed with up to about 15% by weight, preferably up to about 10% by weight, based on the blocked isocyanate prepolymer, of organic solvents to adjust them to the optimum processing viscosity of from about 20 to 40,000 mPas at 20° C. Since the isocyanate groups are blocked, the solvents used need not necessarily be inert towards isocyanate groups. For example, the solvents used may be isopropanol, ethylene glycol monomethyl ether and ethylene glycol monoethyl ether and the acetic acid esters thereof, methyl ethyl ketone, cyclohexanone, butyl acetate or DMF.
According to the present invention, the crosslinking component used for the blocked isocyanate prepolymer is preferably 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, which is an aliphatic diamine having a very low vapor pressure which is liquid at room temperature. Examples of other diamines include 4,4'-diamino-dicyclohexylmethane (at least 75% of the diamine being the cis-cis-isomer), 4,4'-diamino-3,3',5,5'-tetramethyl-dicyclohexylmethane and the homologous tetraethyl, tetrapropyl and tetraisopropylderivatives, 4,4'-diamino-3,5-dimethyl-3',5'-diethyl-dicyclohexylmethane and 4,4'-diamino-3,3'-diisopropyl-dicyclohexylmethane.
The blocked isocyanate prepolymers and diamine crosslinking agents are generally mixed in proportions of the equivalent weights thereof, although less than complete crosslinking may be suitable for certain purposes, so that the equivalent ratio of blocked NCO to NH 2 used according to the present invention is generally from about 1.35:1 to about 0.95:1, preferably from about 1.25:1 to about 1:1.
The reactive mixtures according to the present invention may be mixed with known additives, such as pigments, UV-stabilizers, levelling agents, antioxidants, fillers or blowing agents, to produce the finished coating compounds ready for use.
The thermosetting reactive mixtures may be used to produce coatings by the direct or reversal coating process in the conventional coating installations. Coatings having differing properties, e.g. adhesive coats, foam coats or top coats, may be produced according to the particular specific chemical structure of the isocyanate prepolymer.
For reversal coating by the process according to the present invention, the reactive mixture for the top coat is applied in a quantity of from about 30 to 100 g/m 2 to a suitable intermediate support, e.g. a separating paper, and hardened in a drying channel. The reactive mixture for the adhesive coat is then applied to the dry top coat, again in a quantity of from about 30 to 100 g/m 2 , the substrate is laminated to it and the coating is cured in another drying channel at from about 120° to 190° C., preferably from about 140° to 170° C., and the coated substrate is then removed from the separating support. One could, of course, equally well use the coating compounds according to the present invention only for producing the top coat or the adhesive coat and use a conventional coating system for the other coat.
As mentioned above, the reactive mixtures may also be applied directly to the textile substrate by the direct coating process. The solvent-free or low solvent character of the coating compounds according to the present invention is a great advantage in this method for the production of thick coatings having an even surface. By applying the mixtures in quantities of from about 100 to 200 g/m 2 , technical coatings about 0.4 mm in thickness may be produced by this method in only a few stages.
If the coating compositions according to the present invention are required for the production of foam layers, compounds which release gas when heated are added as blowing agents and foam stabilizers are also preferably added. Suitable additives have been described, for example, in German Offenlegungsschrift No. 1,794,006 (British Pat. No. 1,211,339) and in U.S. Pat. No. 3,262,805.
The known PUR reactive systems could generally only be used for the production of interlayers, for example, adhesive layers or foam layers. When the systems were used for the production of top coats, the defects mentioned above were encountered, such as insufficiently dry hand or physiologically undesirable properties of the starting components. From the wide range available in the known art, it was not to be expected that the particular reactive system obtained by the process according to the present invention would also be able to be used for the production of top coats for coating textiles. It was, therefore, surprising to find that top coatings comparable to those obtainable from PUR solutions in the mechanical properties thereof could also be produced according to the present invention.
The advantage of the process according to the present invention compared with the known art also lies in the fact that the starting components used are, according to our present state of scientific knowledge, physiologically harmless.
The following Examples illustrate the present invention.
EXAMPLES
Preparation of Blocked Isocyanate Prepolymers
Prepolymer A
4,000 g of a hydroxyl polyether having a molecular weight of 6,000 based on trimethylol propane and propylene oxide and 275 g of a hydroxyl polyether having a molecular weight of 550 based on bisphenol A and propylene oxide are reacted with 375 g of 4,4'-diisocyanatodiphenylmethane and 261 g of 2,4-diisocyanatotoluene at from 80° to 90° C. until the isocyanate content is just below the calculated amount of 2.56% by weight. The mixture is then stirred into 261 g of butanone oxime at from 60° to 70° C. No isocyanate may be detected by IR spectroscopy after about 20 minutes. The blocked isocyanate prepolymer, a clear colorless liquid having a viscosity of about 50,000 mPas at 20° C., has a determinable latent isocyanate content of 2.34% by weight, and hence an isocyanate equivalent weight of 1,800.
Prepolymer B
2,000 g of a polyether having a molecular weight of 6,000 based on trimethylol propane and propylene oxide, 1,000 g of a linear polyether having a molecular weight of 1,000 based on propylene glycol and propylene oxide, 1,450 g of a linear polyester having a molecular weight of 1,700 based on hexane diol-(1,6), neopentyl glycol and adipic acid and 22.5 g of butane diol-(1,4) are reacted with 1,125 g of 4,4'-diisocyanatodiphenylmethane and 174 g of 2,4-diisocyanatotoluene at from 80° to 90° C. for about 3 hours, until the isocyanate content is just below the calculated content of 4.26% by weight. 496 g of butanone oxime and 696 g of ethylene glycol monomethyl ether acetate are then rapidly stirred in at from 60° to 70° C. No isocyanate may be detected IR spectroscopically after 20 minutes. The blocked isocyanate prepolymer, a colorless clear liquid having a viscosity of about 40,000 mPas at 20° C., has a determinable latent isocyanate content of 3.3% by weight, and hence an isocyanate equivalent weight of 1,280.
Prepolymer C
2,000 g of a hydroxyl polyester having a molecular weight of 1,700 based on hexane diol-(1,6), neopentyl glycol and adipic acid are reacted with 358 g of 2,4-diisocyanatotoluene at from 80° to 90° C. until the isocyanate content is 4.25% by weight. 174 g of butanone oxime and 250 g of ethylene glycol monomethyl ether acetate are then rapidly stirred into this prepolymer at 70° C. No isocyanate groups may be detected IR spectroscopically after about 20 minutes. The blocked isocyanate prepolymer, a colorless clear liquid having a viscosity of about 40,000 mPas at 20° C., has a determinable latent isocyanate content of 3.5% by weight, and hence an isocyanate equivalent weight of 1,200.
EXAMPLE 1
This Example illustrates the production of a textile coating consisting of a cotton substrate, an adhesive coat and a top coat by the reversal process.
The paste used for the adhesive coat consists of 1,800 g of prepolymer A and 119 g (i.e. an equimolar quantity) of 4,4'-diamino-3,3'-dimethyl-dicyclohexylmethane. Its viscosity at room temperature is about 30,000 mPas and remains unchanged for at least 2 weeks.
The paste for the top coat comprises 1,280 g of prepolymer B and 119 g (i.e. an equimolar quantity) of 4,4'-diamino-3,3'-dimethyl-dicyclohexylmethane. In addition, it contains 10% by weight of a commercial pigment triturate, 0.2% by weight of silicone oil and 2% by weight of a silicate filler. The viscosity of this paste when ready for use is about 40,000 mPas at room temperature.
This top coat is applied to a separating paper in a thickness corresponding to 70 g/m 2 by means of a roller applicator in a coating machine equipped with two coating tools and the paste is then cured in a drying channel at from 140° to 160° C. for 2 minutes. The paste for adhesive coat described above (applied at 60 g/m 2 ) is applied in a similar manner to the cured top coat by means of the second coating tool. The textile web, a napped cotton fabric, is then laminated to it. The adhesive coat is subsequently cured at from 140° to 160° C. for from 2 to 3 minutes in the second drying channel.
The coating has a dry, soft hand having a surface hardness in the region of Shore A 80. It has good folding resistance, resistance to chemical dry cleaning agents and resistance to hydrolysis.
EXAMPLE 2
A textile coating is prepared consisting of a cotton substrate and an adhesive coat, foam coat and top coat by the reversal process.
The pastes for the adhesive coat and the top coat have the same composition as described in Example 1.
The paste for the foam coat comprises 1,280 g of prepolymer B and 119 g (i.e. an equimolar quantity) of 4,4'-diamino-3,3'-dimethyl-dicyclohexylmethane. In addition, it contains 1,5% by weight of diphenyl-3,3'-disulphone hydrazide as blowing agent, 0.2% by weight of silicone oil and 2% by weight of a silicate filler. The viscosity of this paste, when ready for use, is about 40,000 mPas at room temperature.
Using the second coating tool in the coating machine described in Example 1, the top coat paste is applied to a separating paper in a quantity of 60 g/m 2 and the paste is hardened in the following drying channel at from 140° to 160° C. for from 1 to 3 minutes, depending on the efficiency and arrangement of the nozzles in the drying channel. The crosslinked top coat is rolled together with the separating paper. After this operation, the top coat on the separating paper is returned to the beginning of the coating machine. The paste for the foam coat is applied to the top coat in a quantity of 180 g/m 2 using the first coating tool and the paste is foamed in the drying channel at from 140° to 160° C. and crosslinked. In the second coating tool, the paste for the adhesive coat is applied to the foam layer in a quantity of 60 g/m 2 , using a coating knife. The textile web, an unnapped cotton fabric, is then added by laminating. After further curing in the drying channel and passage through the cooling rollers, the coating is stripped off the separating paper and rolled up. The coating has a dry and soft hand. Its folding strength is very high, even after the aging test by hydrolysis at 90° C.
EXAMPLE 3
Preparation of a thick, weldable coating for a tarpaulin, using the direct coating process.
The paste for the adhesive coat comprises 1,280 g of prepolymer B and 102 g of 4,4'-diamino-3,3'-dimethyldicyclohexlmethane. It contains the reactive components in an equivalent ratio of NCO/NH 2 =1.25:1. In addition, the paste contains 2% by weight of a silicate filler, 0.5% by weight of silicone oil and 10% by weight of a PVC plastisol.
The top coat paste comprises 1,200 g of prepolymer C and 119 g (i.e. an equimolar quantity) of 4,4'-diamino-3,3'-dimethyl-dicyclohexylmethane. In addition, the top coat paste contains 10% by weight of a ground pigment powder and 2% by weight of silicone oil. The paste when ready for use has a viscosity of about 40,000 mPas at room temperature.
Using a coating machine of the type mentioned in Examples 1 and 2, the paste for adhesive coats described above is applied to a polyester textile web in a quantity of 100 g/m 2 by means of the first roller coater. This adhesive coat is cured in the following drying channel at from 140° to 160° C. The top coat paste is applied to this adhesive coat in a quantity of 200 g/m 2 in the second coating tool and cured in the second drying channel in the manner described above.
The coating process described here may, if necessary, also be used for coating the undersurface of the tarpaulin.
The tarpaulin is obtained in a thickness of about 0.3 mm and has good resistance to light and weathering. Its folding strength is very high. The tarpaulin may be welded both by heat and by high frequency.
Although the invention has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims. | The present invention relates to thermosetting two-component coating compositions containing
(A) a prepolymer having an average molecular weight of from 1,000 to 15,000 having an average of from 2 to 4 ketoxime-blocked aromatic isocyanate groups;
(B) a crosslinking agent corresponding to the following general formula: ##STR1## wherein R 1 , R 2 , R 3 and R 4 independently represent hydrogen or C 1 - to C 3 -alkyl groups with the proviso that if R 1 to R 4 all are hydrogen, 75% of the diamine have the cis,cis-structure and optionally
(C) pigments, fillers blowing agents or other known additives. The equivalent ratio of blocked isocyanate groups to NH 2 groups is from about 1.35:1 to about 0.95:1, and the coating composition contains not more than about 15% by weight of organic solvents and is free from aqueous polymer dispersions or solutions. The coating compositions may be applied to substrates by the direct or reverse process and may be applied as a top coat, adhesive coat or foam coat. | 3 |
BACKGROUND OF THE INVENTION
[0001] Certain embodiments of the present invention generally relate to conductive pads or contacts of electronic circuit cards, electrical cable assemblies, electrical components and the like, and more particularly to conductive pads that protect against electrical and electrostatic charge and build up on electrical elements that are mated with the conductive pads
[0002] Various electronic systems, such as computers, comprise a wide array of components mounted on circuit boards, such as daughtercards and motherboards that are interconnected to transfer signals and power throughout the systems. Circuit cards having mating contacts are used to transfer signals and power between the circuit boards and other components of the systems. Various cable assemblies are used as well to transfer signals between components.
[0003] [0003]FIG. 1 is an isometric view of a conventional circuit card 10 housed in a connector to interconnect circuit boards and other components. The circuit card 10 includes a mating edge 12 , a top edge 14 and a channel edge 16 defining a main body 17 therebetween. The circuit card 10 includes a plurality of conductive pads 18 (signal and ground conductive pads) arranged along the mating edge 12 of the main body 17 . Conductive pads 22 (ground and signal pads) are arranged along the channel edge 16 of the main body 17 . Traces 26 connect corresponding conductive pads 18 and 22 . The traces 26 are staggered on opposite sides of the circuit card 10 and connected to corresponding conductive pads 18 and 22 through vias 20 and 24 , respectively. The traces 26 may also be positioned to electrically connect two or more vias 20 or 24 .
[0004] The channel edge 16 is received and retained within a channel of a connector housing (not shown). Typically, contact pins (not shown) engage the conductive pads 22 through cavities within the channels. Also, contacts (not shown) electrically connect conductive pads 18 on one circuit card 10 to conductive pads 18 on another circuit card 10 .
[0005] Different types of circuit cards, which may be used in various applications, are known in the art. The circuit cards may be housed or retained in a wide variety of housings. The circuit card 10 is merely an example of a typical circuit card having conventional conductive pads 18 and 22 . Typically, conductive pads 18 and 22 , which may be used on circuit cards and on other electrical components, are single unitary conductive pieces directly connected to traces 26 .
[0006] In order to establish electrical contact with the circuit card, a mating element of a corresponding circuit board or electrical component contacts the conductive pad. Often, electrostatic or other electrical energy builds up in the mating element. Often, an electrical charge may arc from the mating element to the circuit card. Also, when the mating element initially contacts the conductive pad, electrostatic energy built up on the mating element is discharged into the conductive pad. The electrostatic or electrical charge travels from the conductive pad through the electrical path emanating from the conductive pad. Typically, the electrical path leads to another component. The circuitry of the component, however, may not be able to handle the surge of electrostatic energy. Often, the electrostatic or electrical charge, or surge, may degrade or destroy the circuitry of components within an electrical system.
[0007] Thus, a need exists for a conductive pad that protects against the harmful effects of an electrostatic discharge.
BRIEF SUMMARY OF THE INVENTION
[0008] Certain embodiments of the present invention provide a circuit card or electrical mating component having a conductive pad configured to join a mating element having a charge build-up. The conductive pad comprises first and second contact portions separate and distinct from one another and a charge-controlling device. The first contact portion is configured to receive the mating element before the second contact portion receives the mating element. The charge-controlling device is connected to the first contact portion to establish an electrical path in which the charge build-up is discharged through the charge-controlling device. The charge-controlling device may be surface mounted, or positioned within the circuit card or electrical mating component.
[0009] Certain embodiments of the present invention also provide a bifurcated conductive pad positioned on a circuit card having a main body and a mating edge. The bifurcated conductive pad receives a mating element having a built-up charge. The conductive pad comprises an initial contact portion and a final contact portion, wherein the initial contact portion is configured to receive the mating element before the second contact portion receives the mating element. At least one of the initial and final contact portions is grounded so that the final contact portion receives a reduced amount of the built-up charge.Certain embodiments of the present invention also provide a circuit board comprising a main body and a charge-controlling conductive pad system. The charge-controlling conductive pad system includes at least one surface mount pad positioned on said main body; and a resistor mounted on said at least one surface mount pad, wherein said at least one surface mount pad is connected to ground
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0010] [0010]FIG. 1 illustrates an isometric view of a conventional circuit card configured to be mounted in a connector housing.
[0011] [0011]FIG. 2 illustrates a side view of a circuit card formed according to an embodiment of the present invention.
[0012] [0012]FIG. 3 illustrates a side view of a portion of a circuit card formed according to an embodiment of the present invention.
[0013] [0013]FIG. 4 illustrates a partial end view of a mating edge of a circuit card formed according to an embodiment of the present invention.
[0014] [0014]FIG. 5 illustrates a partial plan view of a top edge of a circuit card formed according to an embodiment of the present invention.
[0015] [0015]FIG. 6 illustrates a schematic diagram representative of a charge-controlling system according to an embodiment of the present invention.
[0016] [0016]FIG. 7 illustrates a side view of a circuit card formed according to an alternative embodiment of the present invention.
[0017] [0017]FIG. 8 illustrates a partial plan view of a top edge of a circuit card formed according to an alternative embodiment of the present invention.
[0018] [0018]FIG. 9 illustrates a side view of a circuit card formed according to an alternative embodiment of the present invention.
[0019] [0019]FIG. 10 illustrates a partial sectional view of the circuit card of FIG. 9 taken along line 10 - 10 in FIG. 9.
[0020] The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, certain embodiments. It should be understood, however, that the present invention is not limited to the arrangements and instrumentalities shown in the attached drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0021] [0021]FIG. 2 illustrates a side view of a circuit card 28 according to an embodiment of the present invention. One or more circuit cards 28 may be mounted in connector housings having a variety of shapes and sizes. The circuit card 28 includes a mating edge 30 , a top edge 32 , a back edge (not shown) and a bottom edge (not shown) that define a main body 34 . The circuit card 28 also includes a plurality of charge-controlling pads 36 , which may be signal or ground pads. The charge-controlling pads 36 may be used to control electrical charges exchanged between the circuit cards 28 and matable components during mating. For example, the charge-controlling pads 36 may control electrostatic discharge (ESD) from a mating element to the circuit card 28 . The charge-controlling pads 36 are bifurcated pads in that they include an initial contact portion 38 and a final contact portion 40 separated by a gap 41 of non-conductive circuit board material. The initial contact portion 38 and the final contact portion 40 include vias 42 and 44 , respectively, that interconnect parallel initial and final contact portions 38 and 40 located on opposite sides of the circuit card 28 . The final contact portions 40 may be connected to traces 46 , which provide an electrical connection to other conductive pads, electrical components, etc., on the circuit card 28 .
[0022] It is to be understood that the charge-controlling pads 36 may be used with circuit cards, or any elements or component that have a conductive surface that is mated with another conductive surface. That is, the charge-controlling pads 36 may be used within electrical connectors, electrical cable assemblies, chassis assemblies, motherboards, daughtercards, and various other electrical components in which electrical mating between two elements is needed. For example, the charge controlling pads 36 may be utilized with electrical cable assemblies such as those disclosed in U.S. Pat. No. 5,766,027, issued to Fogg (the '027 patent), which is herein incorporated by reference in its entirety. The charge-controlling pads 36 may be used on, or as, contact portions of the electrical cable assemblies disclosed within the '027 patent.
[0023] A charge-controlling device 47 , such as a resistor, is positioned within or on the surface of the circuit card 28 proximate the gap 41 . The charge-controlling device 47 may be connected to the initial and final contact portions 38 and 40 through traces. The initial contact portion 38 and the final contact portion 40 may be electrically connected through the charge-controlling device 47 . A variety of charge-controlling devices 47 may be used depending on the configuration. FIGS. 3-5 show exemplary configurations for charge-controlling devices 47 . The charge-controlling device 47 may be surface mounted or deposited (such as a carbon deposit on a thick film circuit board) on the circuit card 28 between the initial contact portion 38 and the final contact portion 40 . Alternatively, the charge-controlling device 47 may be embedded within the circuit card 28 . The charge-controlling device 47 may be any suitable material that safely and efficiently resists a predetermined voltage threshold.
[0024] In operation, an electrically conductive mating element 45 , such as a terminal contact, is moved along the direction of arrow A to mate with the charge-controlling conductive pad 36 such that the mating element 45 engages the initial contact portion 38 before engaging the final contact portion 40 . That is, the mating process includes two stages, namely an initial mating stage and a final mating stage.
[0025] During the initial mating stage, the mating element 45 may discharge an electrostatic surge or spike, which has been stored on or within the mating element 45 and/or circuitry connected thereto. Also, an electrical surge, such as a power signal, may arc from the mating element to the charge-controlling pad 36 . The electrostatic or electrical surge travels from the initial contact portion 38 into the via 42 . The electrostatic or electrical surge then travels through the via 42 to a trace (not shown) connected to the charge-controlling device 47 , which impedes, diminishes, attenuates or otherwise resists the flow of the electrostatic or electrical surge. A diminished electrical signal then travels from the charge-controlling device 47 to a trace that is electrically connected to the via 44 of the final contact portion 40 .
[0026] Optionally, the initial contact portion 38 may not be electrically connected to the final contact portion 40 . Instead, the via 42 may be electrically connected to a trace and the charge-controlling device 47 , which in turn is electrically grounded through a trace. The grounding trace need not be electrically connected to any portion of the final contact portion 40 . Thus, as the mating element 45 is slid or otherwise moved into position over the charge-controlling conductive pad 36 , an electrostatic or other electrical charge is received by the initial contact portion 38 , and discharged through the charge-controlling device 47 . Hence, the full electrostatic or electrical charge is not introduced onto the final contact portion 40 , where the electrical path from the initial contact portion 38 is grounded. Because the initial contact portion 38 is grounded, the charge-controlling conductive pad 36 , and consequently the circuit card 28 , does not store or experience excess charge. As the mating element 45 is moved beyond the initial mating position into a final mating position over the final contact portion 40 , the possibility of an electrostatic or other electrical surge traveling from the final contact portion 40 to any electrically connected component is minimized due to the mating element 45 first discharging an electrostatic or other electrical charge through the initial contact portion 38 .
[0027] [0027]FIG. 3 illustrates a sectional view of the circuit card 28 according to an alternative embodiment of the present invention. The charge-controlling conductive pads 36 may include a charge-controlling device 48 , such as a resistor, surface mounted on gap 41 and connecting the initial contact portion 38 to the final contact portion 40 . In this embodiment, the initial contact portion 38 need not be grounded. Instead, the resistive qualities of the charge-controlling device 48 are sufficient to adequately dissipate the electrostatic or other electrical charge between the initial contact portion 38 and the final contact portion 40 .
[0028] [0028]FIG. 4 illustrates an end view of a portion of a circuit card 28 formed according to an alternative embodiment of the present invention. As shown in FIG. 4, the arrow A (depicted by X) is oriented into the page. The initial contact portions 38 and final contact portions 40 (shown in FIG. 3) are positioned proximate the mating edge 30 on the sides of the circuit card 28 such that a charge-controlling device 50 (such as a resistor) and trace segments 51 provide an electrical path between each side of the initial and final contact portions 38 and 40 , respectively. The charge-controlling device 50 may be positioned in, or formed integrally with, vias 42 (and also vias 44 ). The electrical path including the charge-controlling device 50 may also be grounded.
[0029] [0029]FIG. 5 illustrates a partial plan view of a top edge of a circuit card formed according to an alternative embodiment of the present invention. The initial and final contact portions 38 and 40 are positioned on the sides of circuit card 28 such that the vias 42 and 44 provide an electrical path between each side of the circuit card 28 . A charge-controlling device 52 , such as a resistor, may be positioned between the via 42 of the initial contact portion 38 and the via 44 of the final contact portion 40 . Additionally, the electrical path including the charge-controlling device 52 may be grounded.
[0030] [0030]FIG. 6 illustrates a schematic diagram representative of a charge-controlling system 54 according to an embodiment of the present invention. The system 54 includes initial and final contact portions 38 and 40 connected by way of a trace 56 . The trace 56 is in turn electrically connected to a charge-controlling device 58 , which is in turn connected to ground 60 (that is, the charge-controlling device 58 is grounded). Electrostatic or other electrical surges or spikes travel from the initial contact portion 38 into the charge-controlling device 58 (such as a resistor). The electrostatic or electrical surges or spikes are dissipated by the charge-controlling device 58 and then passed to ground 60 .
[0031] Optionally, more than one charge-controlling device may be used within the conductive pad 36 . For example, one charge-controlling device may be positioned between the initial contact portion 38 and the ground, while another charge-controlling device may be positioned between the initial contact portion 38 and the final contact portion 40 . Also, multiple ESD-controlling devices may be positioned within a single electrical path. For example, two ESD-controlling devices may be positioned in series or in parallel between the initial contact portion 38 and the ground.
[0032] Additionally, the conductive pad 36 may be bifurcated into more than two parts. That is, the conductive pad 36 may include an initial, intermediate and final contact portions. Further, a plurality of intermediate contact portions may be positioned between the initial and final contact portions. The intermediate contact portions, similar to the initial contact portions, may be grounded and/or connected to the final contact portions through charge controlling devices and/or traces.
[0033] [0033]FIG. 7 illustrates a side view of a circuit card 100 formed according to an alternative embodiment of the present invention. One or more circuit cards 100 may be mounted in connector housings having a variety of shapes and sizes. The circuit card 100 includes a mating edge 102 , a top edge 104 , a back edge (not shown) and a bottom edge (not shown) that define a main body 106 . The circuit card 100 also includes a plurality of charge-controlling pads 108 . The charge-controlling pads 108 include an initial contact portion 110 and a final contact portion 112 separated by a gap 114 . A surface mounted resistor 116 is disposed within the gap 114 and connects the initial contact portion 110 to the final contact portion 112 . Only the initial contact portion 110 includes a via 118 . The via 118 interconnects the initial contact portion 110 to a ground plane (shown with respect to FIG. 8) located on the opposite side of the circuit card 100 . The final contact portions 112 may be connected to traces 120 , which provide an electrical connection to other conductive pads, electrical components, etc., on the circuit card 100 .
[0034] The charge-controlling pads 108 may be utilized with electrical cable assemblies such as those disclosed in the '027 patent. The charge-controlling pads 108 may be used on, or as, contact portions of the electrical cable assemblies disclosed within the '027 patent.
[0035] A variety of charge-controlling devices 116 may be used depending on the configuration. For example, the charge controlling devices 116 may be 1.0 to 10.0 MOhm resistors. In this way, when a mating element (such as mating element 45 shown with respect to FIG. 2) contacts the initial contact portion 110 , any electrostatic discharge from the mating element travels from the initial contact portion 110 to the ground plane through the via 110 . Further, electrostatic charge is dissipated by shorting the final contact portions 112 to the ground plane through the charge-controlling devices
[0036] [0036]FIG. 8 illustrates a partial plan view of the top edge 114 of the circuit card 100 formed according to an alternative embodiment of the present invention. The initial contact portion 110 on a first side 122 of the circuit card 100 is electrically connected to a ground plane 124 on the second side 126 through the via 118 . As shown in FIG. 8, the charge-controlling device 116 is surface mounted on the first side 122 and electrically connects the initial contact portion 110 to the final contact portion 112 . Electrostatic charge does not build up on the circuit card 100 because any such charge is dissipated through the charge-controlling device 116 , and/or passed to the ground plane 124 . Optionally, no via 118 may connect the initial contact portion 110 to the ground plane 124 . Instead, any electrostatic energy may be sufficiently dissipated through the charge-controlling device 116 .
[0037] In general, embodiments of the present invention may be used with a variety of electrical components, such as electrical connectors, electrical cable assemblies and chassis assemblies. Embodiments of the present invention provide an improved conductive pad that may be used with electrical components that mate with other electrical components. Further, the bifurcated conductive pads provide electrical mating between electrical components that safeguards against electrostatic discharge (ESD), arcing, and other electrical spikes or surges from one component to the other.
[0038] [0038]FIG. 9 illustrates a side view of a circuit card 200 formed according to an alternative embodiment of the present invention. Circuit card 200 includes a mating edge 212 , a top edge 214 , a back edge (not shown) and a bottom edge (not shown) that define a main body 216 . Circuit card 200 includes a charge controlling system 218 that includes a contact pad 220 , a first surface mount pad 222 , an additional surface mount pad 224 , and a charge controlling device 226 surface mounted between surface mount pad 222 and surface mount pad 224 . Surface mount pad 222 is also connected to a signal trace 228 on circuit card 200 . In an exemplary embodiment, charge controlling device 226 is a resister. Surface mount pad 224 includes a via 228 that connects surface mount pad 224 to a ground plane (see FIG. 10). The ground plane may be either an internal layer of circuit card 200 or on the opposite surface of the circuit card 200 . This embodiment provides for flexibility in the circuit layout since the charge controlling device 226 need not be immediately proximate the contact pad 220 or the card mating edge 212 .
[0039] [0039]FIG. 10 illustrates a partial sectional view of the circuit card 200 of FIG. 9 viewed from the line of sight 10 - 10 in FIG. 9. The via 228 is shown extending through circuit card 200 and connecting surface mount pad 224 to ground at 230 at the surface of the circuit card 200 or alternatively at 232 representing an internal layer at ground within circuit card 200 . Charge controlling device 226 is surface mounted between surface mount pads 222 and 224 . Electrostatic charges are dissipated in charge controlling device 226 and/or passed to ground.
[0040] While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims. | A bifurcated conductive pad positioned on an electrical mating component, such as a circuit card, a contact portion of a cable assembly, or the like, having a main body and a mating edge. The bifurcated conductive pad receives a mating element having a built-up charge. The conductive pad comprises an initial contact portion and a final contact portion. The initial contact portion is configured to receive the mating element before the final contact portion receives the mating element, and wherein at least one of the initial and final contact portions is grounded so that the final contact portion receives a reduced amount of the built-up charge. | 8 |
TECHNICAL FIELD
[0001] This disclosure relates to protective structures for battery enclosures for electric vehicle batteries.
BACKGROUND
[0002] Electric vehicles use batteries that are enclosed in an enclosure or housing that is assembled to the vehicle body. The battery may be assembled to the vehicle body at a location that is spaced from the front, rear and sides of the vehicle. For example, the battery may be assembled below the passenger compartment, in the trunk, in front of the passenger compartment or in a longitudinally extending tunnel.
[0003] The battery must be protected from damage in a collision. The battery housing may be tightly packed with lithium ion battery packs or other types of battery cells. Deformation of the battery housing is to be avoided to prevent intrusion of the housing into the area housing the battery cells. Intrusions into the battery housing may rupture of battery cells and spill the contents of the battery cells.
[0004] When the battery housing is assembled in a central location in the vehicle, e.g. beneath the passenger compartment, limited crush space is available between the side of the vehicle body and the battery enclosure. More crush space is available between the battery enclosure and the front or rear ends of the vehicle. In either situation, there is a long felt and unfulfilled need for an efficient and effective lightweight structure for absorbing energy from a collision that minimizes battery enclosure deformation. The structure must have limited package space requirements while providing added stiffness to the battery enclosure assembly including the impact absorbing structure.
[0005] Some approaches to protecting the battery enclosure have proposed adding beams and cross members on the battery enclosure or extending outboard of the battery enclosure. These approaches add weight to the vehicle and require additional space to package the beams and cross members. Added weight is to be avoided because added weight adversely affects fuel economy. Increasing packaging space requirements adversely affects vehicle design freedom.
[0006] The above problems and other problems are addressed by this disclosure as summarized below.
SUMMARY
[0007] According to one aspect of this disclosure, a housing is disclosed for a traction motor battery of a vehicle. The housing includes a plurality of side walls, a top wall and a bottom wall. Each of the walls includes a plurality of parallel T-shaped guides. The T-shaped guides on the top wall and on the bottom wall extend horizontally and the T-shaped guides on some of the side walls extend vertically. The housing also includes a plurality of elongated attachments assembled between the T-shaped guides.
[0008] According to other aspects of this disclosure, the T-shaped guides may include a pair of cantilevered flanges and a spacing leg that extends from each of the walls to a juncture of the pair of cantilevered flanges. The attachments may include edge portions that have a thickness that is substantially equal to the length of the spacing leg.
[0009] The attachments may include a first edge portion and a second edge portions that are adapted to be received by a pair of parallel T-shaped guides. The attachments may also include a central portion between the first edge portion and the second edge portion that is co-planar with the edge portions. The attachments may include a central portion between the first edge portion and the second edge portion that includes a partially cylindrical wall that protrudes outwardly from the T-shaped guides and connects the first edge portion and the second edge portion. Alternatively, the attachments may include a central portion between the first edge portion and the second edge portion that includes an impact receiving outer face and supporting walls that extend between the central portion and the edge portions.
[0010] The attachments may include a first embodiment including a first central portion between the first edge portion and the second edge portion that includes a first impact receiving outer face and a first pair of supporting walls that extend a depth “D” between the first central portion and the first and second edge portions, and a second embodiment including a second central portion between a third edge portion and a fourth edge portion including a second central portion between the third edge portion and the fourth edge portion that includes a second impact receiving outer face and supporting walls that extend a depth “D” between a second central portion and the third and fourth edge portions, wherein the depth “D” is greater than the depth “d.”
[0011] According to another aspect of this disclosure, the plurality of attachments may include different first and second sets of attachments. The first set of attachments may have a depth “D” measured from the respective wall to an impact receiving surface of the attachment in a direction normal to the wall. The second set of attachments may have a depth “d” measured from the respective wall to an impact receiving surface of the attachment in a direction normal to the wall, wherein the depth “D” is greater than the depth “d.” The attachments may also include a third set of attachments having a depth “d 1 ” measured from the respective wall to an impact receiving surface of the attachment in a direction normal to the wall, wherein the depth “d” is greater than the depth “d 1 .”
[0012] The attachments may include different types of attachments. A first type of attachment may be provided that has a first central portion between a first edge portion and a second edge portion, wherein the first central portion is partially cylindrical. A second type of attachment may have a second central portion between a third edge portion and a fourth edge portion, wherein the second central portion includes a planar impact receiving outer face. The second type of attachment may include first and second supporting walls that extend between the second central portion and the third and fourth edge portions. Alternatively, the planar impact receiving outer face may be provided on an outer side of a planar reinforcement plate.
[0013] According to another aspect of this disclosure, method is disclosed for providing an impact absorbing enclosure for a battery of a vehicle having a battery powered traction motor. The method comprises providing vertically extending walls that have a plurality of parallel vertical guides providing a plurality of attachments and inserting the attachments between the vertical guides to provide the vertically extending walls with an impact absorbing assembly formed by of the attachments on an outer surface of the vertically extending walls.
[0014] According to other aspects of this disclosure as it relates to the method, the method may further comprise providing horizontally extending walls that having a plurality of parallel horizontally extending guides. Providing a plurality of second attachments and inserting the second attachments between the horizontally extending guides to provide the horizontally extending walls with impact absorbing assembly formed by the second attachments on a second outer surface of the horizontally extending walls.
[0015] According to other alternative aspects of this disclosure the vertically extending guides on the vertical walls may be T-shaped guides and the horizontally extending guides on the horizontal walls may be T-shaped guides. The T-shaped guides may include a spacing leg and a pair of cantilevered flanges, wherein the spacing leg extends from each of the walls to a juncture of the pair of cantilevered flanges. The attachments may include edge portions that have a thickness that is substantially equal to the length of the spacing leg.
[0016] According to other aspects of this disclosure, a peripheral space may be defined by the vehicle around the impact absorbing enclosure that is available for inserting the attachments includes small areas and large areas. The method may further include: a first additional step of selecting a first set of attachments having a depth “D” measured from the respective wall to an impact receiving surface of the attachment in a direction normal to the wall, and inserting the first set of attachments in the large areas; and a second additional step of selecting a second set of attachments having a depth “d” measured from the respective wall to an impact receiving surface of the attachment in a direction normal to the wall, and inserting the second set of attachments in the small areas, wherein the depth “D” is greater than the depth “d.”
[0017] The method may also relate to a peripheral space defined by the vehicle around the impact absorbing enclosure that is available for inserting the attachments includes a first area having a first configuration and a second area having a second configuration. The method may include the use of a first type of attachment having a partially cylindrical first central portion between a first edge portion and a second edge portion. The method may further include the use of a second type of attachment having a planar second central portion between a third edge portion and a fourth edge portion, wherein the first area is provided with the first type of attachment and the second area is provided with a second type of attachment.
[0018] The above aspects of this disclosure and other aspects are described below with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a diagrammatic bottom plan view of a vehicle illustrating a battery enclosure disposed on the vehicle frame beneath the passenger compartment.
[0020] FIG. 2 is a perspective view of a first embodiment of a battery enclosure including several different types of attachments provided on the sides and top of the enclosure.
[0021] FIG. 3 is a fragmentary enlarged perspective view of a portion of the battery enclosure illustrated in FIG. 2 .
[0022] FIG. 4 is a fragmentary enlarged cross-sectional view of a portion of the battery enclosure illustrated in FIG. 2 .
DETAILED DESCRIPTION
[0023] The illustrated embodiments are disclosed with reference to the drawings. However, it is to be understood that the disclosed embodiments are intended to be merely examples that may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed are not to be interpreted as limiting, but as a representative basis for teaching one skilled in the art how to practice the disclosed concepts.
[0024] Referring to FIG. 1 , a vehicle 10 is diagrammatically illustrated with a battery 12 for a battery-powered traction motor. The vehicle 10 includes a body 14 that is supported on a frame 16 . A traction motor 18 is also assembled to the frame 16 . The traction motor 18 is a battery-powered traction motor that is powered by the battery 12 to drive the wheels 20 . This disclosure focuses on the enclosure 21 for the battery.
[0025] The body 14 includes a side body 22 , a front bumper 24 and a rear bumper 26 . The battery 12 in the enclosure 21 is shown to be centrally located underneath the passenger compartment of the vehicle 10 . It should be noted that there is a substantially greater amount of space between the battery and the front and rear bumper 24 and 26 compared to the relatively closer spacing of the side body 22 to the battery 12 . Side impact collisions that result in driving the side body 22 toward the battery 12 present a greater challenge when designing attachments for the battery 12 due to the reduced amount of crush space available between the side body 22 and the battery 12 .
[0026] Referring to FIGS. 2-4 , the enclosure, generally indicated by reference numeral 21 , is shown to include a bottom wall 30 (shown in FIG. 1 ) and a top wall 32 . A front wall 36 faces the front bumper 24 (shown in FIG. 1 ) and a rear wall 38 faces the rear bumper 26 (shown in FIG. 1 ). The battery enclosure 21 includes a right side wall 40 and a left side wall 42 . The side walls are joined at corners 44 .
[0027] In the illustrated embodiments three different types of attachments are shown but it should be understood that other configurations and shapes of attachments may be utilized depending in part on the space available within the vehicle. The three types of attachments illustrated include a partially cylindrical attachment 48 , a trapezoidal space defining attachment 50 and a planar attachment 52 .
[0028] The impact absorbing wall 54 of the semi-cylindrical attachment 48 as illustrated in FIGS. 2 and 3 is an arcuate, or semi-cylindrical, wall 54 that forms a semi-cylindrical pocket 56 with the planar wall of the enclosure 21 . The impact absorbing wall 48 is an arcuate shaped elongated member with the arc of the wall being generated about a horizontal axis X when the partially cylindrical attachment 48 is mounted in a horizontal orientation when the partially cylindrical attachment 48 is attached to a top wall 32 or a bottom wall 30 or a vertical axis Y when attached to a vertical wall 36 - 42 . The attachments may also be secured in a horizontal orientation on one or more of the vertical walls. Attachment flanges 58 and 60 are provided on opposite edges of the semi-cylindrical impact absorbing wall.
[0029] The trapezoidal space defining attachment 50 defines a trapezoidal pocket 62 . The attachment 50 includes a spaced wall, or impact absorbing wall 64 , a right ramp wall 66 and a left ramp wall 68 on opposite sides of the impact absorbing wall 64 . The right ramp wall 66 and the left ramp wall 68 extend to right and left attachment flanges 72 and 74 , respectively. As shown the ramp walls 66 and 68 are disposed at about a 45° angle relative to the wall of the enclosure. It should be understood that the orientation of the ramp surfaces could be at any angle or even at a right angle to the wall of the enclosure.
[0030] The planar attachment 52 is a planar member that is attached to one of the walls on the enclosure 21 . The planar attachment 52 has a right edge 76 and a left edge 78 that function as attachment flanges.
[0031] The attachments 48 - 52 are attached to the walls of the enclosure by T-shaped guides 80 that are provided on the enclosure in a parallel orientation. The attachment flanges 58 and 60 of the semi-cylindrical attachment, right and left flanges 72 and 74 of the trapezoidal attachment 50 and edges 76 and 78 are adapted to be received by adjacent T-shaped guides 80 that hold the attachments against the enclosure 21 . The T-shaped guides include a central flange 82 that is attached to a wall on an inner end and extends outwardly to a crossbar 84 . The cross-bar 84 is parallel to the wall of the enclosure to which the T-shaped guide 80 is attached. Generally, one T-shaped guide supports two attachments except at a corner where only one attachment flange requires support.
[0032] Referring to FIG. 4 , the different styles of attachments each have a different depth as measured from the walls and require more or less space. For example, in FIG. 4 the semi-cylindrical attachment 48 is shown to have a depth “D” and the trapezoidal attachment 50 has a depth “d.” Depth “d” is less than depth “D” and would require less packaging space around the enclosure. The depth of the planar attachment is equal to the thickness of the planar attachment 52 and would be less than the depth “d” and would require even less space.
[0033] The ability of the respective attachments to absorb impact energy also varies depending upon the type of attachment. The attachments may be fabricated to have different thicknesses and may be made of different materials including aluminum alloys, steel alloys, fiber reinforced composites or polymers compositions. This disclosure enables the battery enclosure 21 to resist a wide range of impact forces while being accommodated within the packaging space available around the enclosure 21 . Other vehicle components are generally indicated by structure 86 shown in FIG. 4 . The other structure may be frame rails, beams, floor structure, accessories, or the like.
[0034] The T-shaped guides 80 provide a flexible mechanism for supporting the attachments on the enclosure 21 . Changes in the design of a vehicle may impact the space available for the impact absorbing attachments. If there is a reduction in the space available as a result of a design change, a trapezoidal attachment may be substituted for a semi-cylindrical attachment. If a test indicates that additional impact energy absorption is needed on a side or part of one of the sides, stronger or thick attachments may be used or a different style of attachment may be specified.
[0035] The embodiments described above are specific examples that do not describe all possible forms of the disclosure. The features of the illustrated embodiments may be combined to form further embodiments of the disclosed concepts. The words used in the specification are words of description rather than limitation. The scope of the following claims is broader than the specifically disclosed embodiments and also includes modifications of the illustrated embodiments. | A battery housing for a traction motor battery of a vehicle is disclosed that includes attachments retained by parallel T-shaped guides on the outer surface of the walls of the enclosure. The attachments are oriented to extend either in a horizontal orientation or vertical orientation. The depth of the attachments and shape of the attachments may be selected to meet impact force requirements and packaging space limitations imposed by the structure of the vehicle. | 8 |
BACKGROUND OF THE INVENTION
The invention relates to a sewing machine and more particularly relates to a feed dog dropping control mechanism for a sewing machine in which a pulse motor is operated by the signals from an electric control circuit to switch the feed dog to the operative condition and to the inoperative condition.
In the conventional sewing machines with a mechanical pattern generating device, the feed dog dropping mechanism has been operated by manipulation of a knob provided on the machine housing. The manipulation, however, has to overcome a considerable load applied thereto and is hard to the machine operator. Such a mechanism may be operated automatically by using a solenoid or other means. But in this case, the solenoid to be employed must be of a big capacity and requires a large space in the machine housing. Thus there have been practically many problems for operating the feed dog dropping mechanism in association with the pattern selecting elements.
SUMMARY OF THE INVENTION
The present invention has been provided to eliminate the defects and disadvantages of the conventional sewing machines.
It is a primary object of the invention to control the feed dog in association with the pattern selecting operation.
It is a second object of the invention to drive a sewing machine in a reduced speed when an electrically driven device is operated to control the feed dog, thereby to apply no substantial load to the electrically driven device.
The other features and advantages of the invention will be apparent from the following description of the invention in reference to the attached drawings. This invention is employed in a sewing machine provided, in place of a mechanical pattern generating device, with an electric pattern generating device which electrically controls both or one of the needle swinging amplitude and the feeding amount by way of electrically driven elements so as to form the predetermined stitch patterns. According to the invention, the elements for selecting the straight stitching and the zigzag stitching are electrically operated to switch the vertical reciprocating movement of the feed dog to an operative or inoperative condition.
BRIEF DESCRIPTION OF THE DRAWINGS SHOWING THE EMBODIMENTS OF THE INVENTION
FIG. 1 is a perspective view of a sewing machine provided with the invention,
FIG. 2 is a simplified schmatic representation of a feeding mechanism of the sewing machine in accordance with the invention,
FIG. 3 is a perspective view of a control device of the invention,
FIG. 4 is a perspective view of a bracket supporting the control device of the invention,
FIG. 5 is an exploded view of the control device,
FIG. 6 is a perspective view of a lever operated by the control device,
FIG. 7 is an exploded view of a clutch solenoid of the invention,
FIG. 8 is an assembled clutch solenoid partly in a vertical section,
FIG. 9 is a block diagram of an electronic control circuit controlling the control device of the invention,
FIG. 10 is a flow chart for the invention,
FIG. 11 is a perspective view of a control device of the invention showing a second embodiment thereof,
FIG. 12 is an exploded view of the essential part of the control device,
FIG. 13 is a vertical sectioned view of a shaft part of the control device,
FIG. 14 is a block diagram of a electronic control circuit for controlling the control device of the second embodiment of the invention,
FIG. 15 is a front elevational view of a control link of the control device shown in relation to a feed control arm,
FIG. 16 is a flow chart of the block diagram of FIG. 14,
FIG. 17 is a perspective view of a control device of a third embodiment of the invention,
FIGS. 18 and 20 are front elevational views of the control device shown in different operations,
FIG. 19 is a front elevational view of a cam on the control device, and
FIG. 21 is a block diagram of a control circuit for the control device of the invention.
DETAILED DESCRIPTION OF THE INVENTION
In reference to FIG. 1, the reference numeral 1 is a machine housing of a sewing machine provided with a laterally extended bed frame 2 which has a needle plate 3 arranged on the upper face thereof. The reference letter B shows collectively a plurality of pattern selecting elements arranged in a pattern selecting device of the sewing machine. The numeral 4 shows a bracket in the machine housing for supporting the necessary control devices including a pulse motor 5 for controlling a horizontal feeding amount of the feed dog of the sewing machine. As shown, an inverted L-shape lever 6 is turnably mounted on a pivot pin 6a secured to the bracket 4. The lever 6 has a lower end 6c (shown in FIG. 6) connected to a rod 8 which is connected to a plunger 7 and is axially shiftable. A schematical view of a feeding mechanism is shown in FIG. 2. This mechanism may be preferably of the type shown and described in U.S. Pat. No. 3,426,712 issued to Janome Sewing Machine Co. Ltd. The plunger 7 is, as simply illustrated in FIG. 2, axially displaced into or out of holes 10a, 11a formed respectively at the ends of a vertically swingable link 10 and a vertically swingable arm 11. The link 10 is vertically swingable in synchronism with rotation of the sewing machine by a rocking shaft 9, and the arm 11 is at the end thereof loosely mounted on the rocking shaft 9. The vertically swingable arm 11 has a lateral pin 11b which is inserted into a forked part 13a of a base 13 supporting a feed dog 12. One end of the base 13 is pivotally connected to the upper end of a link 15 which is swingable by a rocking shaft 14 to horizontally reciprocate the base 13 in synchronism with rotation of the sewing machine. Thus the feed dog 12 feeds the sewn fabric by a combination movement of the base 13 which is vertically and horizontally reciprocated. It is, therefore, apparent that the feed dog 12 is vertically moved when the plunger 7 is inserted into the holes 10a, 11a of the vertically swingable link 10 and arm 11. It is also apparent that the feed dog 12 is dropped to below the level of the needle plate 3 and becomes vertically inoperative if the plunger 7 is displaced out of the holes 10a, 11a. In FIG. 1, a tension spring 16 is at one end connected to the plunger rod 8 and is at the other end hung to the bed frame so as to bias the rod 8 in the leftward direction and the feed control lever 6 in the clockwise direction.
In FIGS. 1 and 3, the reference numeral 17 is a feed control arm turnably mounted on a pivot pin 17a secured to the bracket 4. One end 17b of the control lever 17 is engaged to the lower face of a horizontally bent end 6e of the control lever 6. Therefore the control lever 17 is biased in the counterclockwise direction by the action of the tension spring 16 influencing the plunger lever 8. A stopper 19 is secured to the bracket 4 and is engaged by the other end of the control lever 17 to limit the counterclockwise turning movement of the lever 17 having a pin 18.
In reference to FIGS. 3, 7 and 8, the numeral 20 is a clutch solenoid secured to a support plate 21 which is secured to the bracket 4 together with the pulse motor 5. The numeral 22 is a solenoid plunger formed with an axial groove 22a at the outer end thereof. The solenoid plunger 22 is connected to a feed control shaft 23 by means of a connecting plate 26 which is inserted at one end into the axial groove 22a of the plunger 22 and is at the other end inserted into an axial groove 23b of the feed control shaft 23, and is connected at both ends thereof to the forms and the latter by means of pins 25, 25. The feed control shaft 23 is placed in a bushing 24 and is provided with a flange 23a at the outer end thereof as shown and is axially displaceable together with the solenoid plunger 22. The axial movement of the feed control shaft 23 is limited in the rightward direction by means of a stop ring 27 secured on the shaft 23. A U-shape element 28 is loosely mounted on the bushing 24 and stradles a part of the bracket 4. The wall 28a of the U-shape element 28 is pressed against the flange 23a of the feed control shaft 23 by means of a spring 29 which is mounted on the bushing 24 between the wall 28a and a part of the bracket 4. In this condition, a clearance (a) is provided between the flange 23a and the rightward end of the bushing 24, and a pin 24 a on the bushing 24 engages a cutout 28b in the wall 28a of the U-shape element 28. The wall 28a has an extended part provided with a pin 30 on the inside thereof, and has another extended part provided with an oblong hole 28c for engaging onto the pin on the feed control lever 17.
In FIGS. 3 and 5, the pulse motor 5 has a motor shaft 5a to which a sensor plate 31 is secured. The sensor plate 31 sets the initial angular position of the motor shaft 5 in cooperation with a block 32 which is secured to the bracket 4 and is provided with a light emitting diode and a photo transistor (not shown) for detecting the presence of the sensor plate 31. A link 33 is also secured to the motor shaft 5, and the turning movement of the link 33 is limited by a stopper 34 secured to the bracket 4. The link 33 is formed with a groove 33a which is to engage the pin 30 on the U-shape element 28 when the link comes to the leftward end position during the turning movement thereof. A feed control belt wheel 35 with a shaft 35a is turnably mounted on the bracket 4, and a feed control arm 36 is secured to the end of the shaft 35a on the opposite side of the bracket 4. The feed control arm 36 is connected to a feed adjusting mechanism (not shown) which is to give a horizontal movement to the feed dog 12. The link 33 and the feed control wheel 35 is connected by a timing belt 37.
In reference to FIG. 9 showing an electronic control circuits diagram for the pulsemotor 5, the arrow marks indicate the flow of electric signals between the circuit elements. ROM is an electronic read only memory and stores a plurality of pattern stitch control signals including a signal for producing straight stitches and also stores the program controls. CPU is a central process unit for performing individual program controls. RAM is a write - read static memory for temporarily storing the processes on effects during the program performance. I/O is an input port. PS is a pattern selecting device operated by way of the pattern selecting elements (B) in FIG. 1 which select a desired pattern in such a manner that the RAM stores the pattern control signal from the ROM. PG is a pulse generator generating a pulse in synchronism with each rotation of the main drive shaft of the sewing machine. The pulse is applied to the CPU to read out a selected pattern signal from the ROM. DV is an electric drive means to drive the horizontal feed control pulse motor 5 and the clutch solenoid 20 in accordance to the signals from the CPU.
The operation of the invention will be described in reference to the flow chart in FIG. 10; IF the power source is introduced, the circuit shown in FIG. 9 becomes operative. A desired pattern is selected by manipulation of the pattern selecting elements (B in FIG. 1,) and the CPU reads out a control signal from the ROM to drivingly control the pulse motor 5 and the clutch solenoid 20 by way of the DV. If the order "DOWN" for dropping the feed dog 12 is selected by manipulation of a pattern selecting element B, it is checked whether the precedingly selected order was "DOWN" or not. If the precedingly selected order was not the "DOWN", the rotation speed of the sewing machine is reduced and then the clutch solenoid 20 is energized. Then the U-shape element 28 is pulled against the compression spring 29 in the direction P by way of solenoid plunger 22 and the control shaft 23 an shown in FIG. 8. Simultaneously the pulse motor 5 is driven and turns the feed control link 33 in the counterclockwise direction until the groove 33a of the link 33 engages the pin 30 on the U-shape element 28. (In this case, the horizontal feeding amount is predetermined and constant, about 2.5 mm in the forward feeding direction in this embodiment.) Subsequently the pulse motor 5 turns back the control link 33 to the end in the clockwise direction with a condition as the groove 33a of the link 33 is in engagement with the pin 30 of the element 28 (In this case, the horizontal feeding amount is predetermined and constant, about 2.5 mm in the backward feeding direction in this embodiment.). Since the recess 28b of the U-shape element 28 is displaced out of engagement with the pin 24a of the bushing 24 when the solenoid 20 is energized, the turning movement of the control link 33 in the clockwise direction turns the U-shape element 28 in the counterclockwise direction in FIG. 3. The counterclockwise movement of the U-shape element 28 turns the feed control lever 17 in the clockwise direction around the pivot pin 17a, because the control lever 17 is connected to the element 28 by the pin 18 which is secured to the lever 17 and is in engagement with the oblong hole 28c of the element 28. As the result, the inverted L-shape feed control lever 6 is turned in the counterclockwise direction and the plunger rod 8 is axially displaced in the rightward direction in FIG. 1, and the plunger 7 is, therefore, displaced out of engagement with the vertical swingable arm 11. Therefore the feed dog 12 is dropped to the position below the level of needle plate 3 and becomes inoperative to the sewn fabric. Then the "DOWN" condition of the feed dog 12 is memorized in the control circuit and the operation process of the circuit returns to the "START". Simultaneously the low speed rotation of the sewing machine is switched to a high speed rotation, and the clutch solenoid 20 is deenergized, and the solenoid plunger 22 and the control shaft 23 are returned to the rightward initial position. The U-shape element 28 is, however, held in the operative position on the bushing 24 by the pin 24a which, in this case, engages a part other than the recess 28b of the wall 28a of the U-shape element 28 which is in cooperation with the control link 33 of the pulse motor 5. Therefore the feed dog 12 is held in the dropped condition. If the order "DOWN" is repeatedly selected, the pulse motor 5 is not driven due to the fact that the "DOWN" has already been precedingly selected.
Subsequently, if a different order ("NO DOWN") other than "DOWN" is selected, the pulse motor 5 is driven by a control signal after it is checked that the sewing machine is in a low speed. Namely the control link 33 of the pulse motor 5 is turned in the counterclockwise direction and turns the U-shape element 28 in the clockwise direction until the recess 28b of the U-shape element 28 comes to a position in alignment with the pin 24a of the bushing 24. Then the U-shape element 28 is axially displaced in the rightward direction by the action of the compression spring 29 until it is stopped by the flange 23a of the control shaft 23 and the pin 30 of the element 28 is disengaged from the groove 30a of the link 33, and the engaging relation is re-established between the pin 24a of the bushing 28 and the recess 28b of the U-shape element 28. Therefore the control lever 17 is turned in the counterclocwise direction around the pivot 17a, and accordingly the plunger 7 is axially displaced into engagement with the hole 11a of the vertically swingable arm 11 by the action of the tension spring 16. As the result, the feed dog 12 is brought up to the operative position above the needle plate 3 and is vertically reciprocated in addition to the horizontal reciprocation thereof. Simultaneously the "NO DOWN" condition is memorized in the control circuit and the operation process of the circuit returns to the "START". The sewing machine is switched to a high speed from a low speed, and the pulse motor drives the horizontal feed adjusting mechanism by way of the control arm 36. According to the invention, it must be noted that the pattern or order selection is normally made when the sewing machine is standstill, but that such a pattern or order selection is possible if it is made when the sewing machine is driven in a high speed.
FIG. 10 of flow chart.
1. High Speed Rotation of Machine
2. Clutch Solenoid OFF
3. Performance of Pattern Program
4. Low Speed Rotation of Machine
5. Precededly DOWN or not?
6. Low Speed Rotation of Machine or not?
7. Clutch Solenoid ON
8. Pulse Motor is driven and Clutch Solenoid is energized
9. Precededly DOWN or not?
10. Low Speed Rotation of Machine or not?
11. Clutch Solenoid OFF
12. Pulse Motor is driven to release Element 28 from Link 33 and then Pattern Program is carried out
13. High Speed Rotation of Machine
14. Perfarmance of Pattern Program
15. Low Speed Rotation of Machine
FIGS. 11-16 show a second embodiment of the invention. The explanation will be made regarding only the parts different from the first embodiment.
In reference to FIGS. 11-13, a control lever 38 is turnably mounted on a pivot 39 secured to the bracket 4 and the one end is engageable to the horizontally bent end 6e of the inverted L-shape lever 6. A pin 40 is secured to the other end part of the control lever 38. A bell-crank lever 42 is turnably mounted on a pivot 43 secured to the bracket 4. The upper arm 42a engages the pin 40 of the control lever 38 by way of an oblong hole formed therein. The pulse motor shaft 5a has a sensor plate 44 secured thereto for setting an initial position of the pulse motor 5 in cooperation with a block 44 which is secured to the bracket 4 and is provided with a light emitting diode and a photo transistor (not shown) for detecting the presence of the sensor plate 44. The pulse motor shaft 5a has a control element 46 secured thereto which is formed with projections 46a and 46b. A feed control element 47 is mounted on the pulse motor shaft 5a between the sensor plate 44 and the control element 46. The feed control element 47 is turnable relative to the shaft 5a, and is connected to the control element 46 by means of a coil spring 50. The feed control element 47 is formed with a projection 47a and a gear 47b. The element 47 is connected to the control element 46 by the spring 50 in such a manner that the face (a) of the projection 47a of the element 47 is pressed against the projection 46b of the control element 46 which is as shown laterally projected a little out of the inner end of the control element 46 toward the feed control element 47. The feed control element 46 is connected to the feed control belt wheel 35 which engages the gear 47b of the element 47 and the gear 35b of the wheel 35. Therefore when the pulse motor 5 is driven, the feed control element 47 is driven via the control element 46, and the feed control wheel 35 is driven to control the feed adjusting mechanism (not shown) by way of the control arm 36 secured to the control shaft 35a of the wheel 35. A stopper 51 is secured to the bracket 4 so as to engage the face (a) of the projection 47a of the control element 47, thereby to stop the rotation of the same when the control element 47 comes to an angular position corresponding to the feeding amount 2.5 mm in the backward feeding direction. On the other hand, the projection 46a of the control element 46 engages the arm 42d of the bell-crank lever 42 when the control element 46 comes to an angular position corresponding to the feeding amount 2.5 mm in the backward feeding direction. FIG. 14 shows a block diagram of the control circuit for the pulse motor 5, which is the same with that shown in FIG. 9 regarding the first embodiment of the invention.
The operation of the second embodiment will be described in reference to the flow chart of FIG. 16; If the order "DOWN" is selected by manipulation of the pattern selecting elements B, the control circuit checks if the order "DOWN" was precededly selected. If the order was not precededly selected, the rotation speed of the sewing machine is reduced in case it has been driven in a high speed, and then the pulse motor 5 is driven. With the drive of the pulse motor, the projection 46a of the control element 46 is turned and engages the arm 42d of the bell-crank lever 42 at an angular position (P) which corresponds to the feeding amount 2.5 mm in the backward direction as shown in FIG. 15A. As the control element 46 is further turned, the projection 47a of the feed control element 47 engages the stopper 51, and the rotation of the element 47 is stopped. The control element 46 is, however, continuously turned in the clockwise direction until the projection comes to an end position which corresponds to the feeding amount 4 mm in the backward direction. In this case, the arm 42d of the bell-crank lever 42 is displaced from the position (P) to the position (q) in the counterclockwise direction as shown in FIG. 15B. With this turning displacement of the bell-crank lever 42, the control lever 38 is turned around the pivot 19 in the clockwise direction. As the result, the inverted L-shape lever 6 is turned in the counterclockwise direction against the action of the tension spring 16. Thus the feed control plunger 7 is axially displaced and disengaged from the hole 11a of the vertically swingable arm 11, and the feed dog 12 is dropped to the inoperative position below the level of the needle plate 3 in the same manner as described in the first embodiment. Then the "DOWN" condition of the feed dog 12 is memorized in the control circuit and the operation process of the circuit returns to the "START", and simultaneously the machine is switched from the low rotation speed to a high rotation speed. If the order "DOWN" is repeatedly selected, the pulse motor 5 is not driven.
Subsequently if an order "NO DOWN" is selected, the control circuit checks that the sewing machine is driven in a reduced low speed, and drives the pulse motor 5 in the reverse direction and alows the arm 42d of the bell-crank lever 42 to return to the position (P) from the position (q), Therefore the control lever 38 is turned in the clockwise direction allowing the inverted L-shape lever 6 to turn in the clockwise direction due to the action of the tension spring 16. As the result, the feed control plunger 7 is axially displaced into engagement with the hole 11a of the vertically swingable arm 11, and the feed dog 12 is brought up to the operative position above the level of the needle plate 3. Then the "NO DOWN" condition is memorized in the control circuit and the operation process of the control returns to the "START", and the sewing machine is switched from the reduced speed to the high speed. Then the pulse motor 5 is disconnected from the feed dropping mechanism and controls only the feed adjusting mechanism (not shown) by way of the feed control arm 36.
FIG. 16--flow chart
1. High Speed Rotation of Machine
2. Performance of Pattern Program
3. Low Speed Rotation of Machine
4. Precededly DOWN or not?
5. Low Speed Rotation of Machine or not?
6. Pulse Motor is driven to drop Feed Dog
7. Precededly DOWN or not?
8. Low Speed Rotation of Machine or not?
9. Pulse Motor is driven to allow Feed Dog to Upper Operative Position
10. High Speed Rotation of Machine
11. Performance of Pattern Program
12. Low Speed Rotation of Machine
FIGS. 17-21 shows a third embodiment of the invention. In this embodiment, a pulse motor 53 for controlling the lateral swinging movement of the needle is secured to a bracket 52 which is fixedly mounted in the machine housing. The pulse motor 53 has a central drive shaft 54 which is as shown fixedly provided with a base element 55. The base element 55 is formed with projections 55a, 55b with a space therebetween on the periphery thereof. The rotation of the base element 55 is limited by a stopper 56 formed on the bracket 52. A sensor or a light screening plate 57 is secured to the base element 55 to cooperate with an element 58 provided with a light emitting diode and a photo transistor and is fixedly mounted on the bracket 52 to generate a signal indicating an angular position of the motor shaft 54. A needle swinging control cam 59 is secured to the base element 55. The control cam 59 has on the periphery thereof a region A for controlling the needle swinging mevemement and a region B for controlling the exchange of the needle hole of the needle plate from the needle hole for straight stitches to the one for zigzag stitches and vice versa as shown in FIG. 19. The control cam 59 is engaged by a pin 61 secured to one end of a L-shape lever 60 which is turnable around a pivot 62 on the bracket 52. The L-shape lever 60 is at the other end connected to a transmission rod 63 for controlling the needle swinging movement. The L-shape lever 60 is held in engagement with the control cam 59 by means of a spring 64 biasing the lever 60 in the counterclockwise direction as shown in FIG. 18. When the pin 61 engagles the point (A1) of the control cam 59, the transmission rod shifts the needle to the extreme left end of the whole needle swinging region. On the other hand, when the pin 61 engages the point (A2) of the control cam 59, the transmission rod 63 shifts the needle to the extreme right end of the whole needle swinging region. When the pin 61 engages the region B of the control cam 59, the needle is in the center position of the whole needle sweinging region.
Reference numeral 65 is a control shaft for changing the needle hole of the needle plate, and has a control arm 66 secured thereto. The control shaft 65 is turnably mounted on a boss 67 of the bracket 52. The control lever 66 is pressed against a stopper (not shown) by a spring (not shown) in the counterclockwise direction to the position as shown in FIG. 18. As shown a pin 68 is secured to the base element 55. The pin 68 is adapted to engage the control lever 66 and turns the same in the clockwise direction if the base element 55 is turned in the counterclockwise direction together with the motor shaft 54. In this case, the pin 61 of the needle swinging control lever 60 engages the region B of the control cam 59 as shown in FIG. 20 which shows that the pulse motor 53 has been driven in the counterclockwise direction to the maximum extent to set the sewing machine to a condition for stitching the straight stitches, in which the needle has been brought to the center position and the needle hole has been reduced for the straight stitches from the laterally extended zigzag stitching needle hole. On the other hand, FIG. 18 shows that the sewing machine has been set to a condition for stitching the zigzag stitches in which the needle has been brought to a position defined by the region A of the control cam 59 and the needle hole has been laterally enlarged for zigzag stitches from a reduced hole for straight stitches. The light screening plate 57 is positioned on the base element in respect to the photo emitting element 58 so as to engage the pin 61 to the point (A1) of the control cam 59 corresponding to the reset position of the pulse motor 53 when the power source is introduced.
FIG. 21 shows a block diagram of control circuit for the third embodiment, in which the solid lined arrow marks indicate the flow of electric signals between the circuit elements and the broken lined arrow marks indicate mechanical relations of the elements. The block diagram will be explained regarding only the points different from the block diagram of FIG. 9; DV is an electric drive device for controlling the needle swinging mevement and the feeding movement, and drives the needle and needle hole control pulse motor 53 and the feed control pulse motor 5 in accordance to the signals from the central processing unit (PCU). Reference numerals 58, 32 are sensors respectively cooperating with the respective light screening plates 57, 31 generate a pulse signal which is transmitted to the central processing unit (PCU) for resetting the respective pulse motors 53, 5.
The operation of the third embodiment is as follows; If the power source is introduced, the circuit in FIG. 21 becomes operative. In this instance, if the screening plate 57 is not in alignment with the sensor element 58 as shown in FIG. 20, the pulse motor 53 is driven to a reset position as shown in FIG. 18 where the screening plate 57 is in alignment with the sensor 58. Simultaneously the central processing unit PCU checks by the signal from the pulse generator PG that the needle is positioned approximately at the upper dead point. In this condition of FIG. 18, the needle hole control lever 66 is in an extreme end position in the counterclockwise direction and therefore the laterally extended needle hole is provided for zigzag stitches, and the pin 61 engages the region A of the control cam 59. Therefore if a pattern including zigzag stitches is selected by way of pattern selection device PS, the pattern can be stitched. Namely the pulse motor 53 is driven within the confined region A of the control cam 59 by the electric drive device DV which is operated by the central processing unit PCU receiving a pulse per stitch from the pulse generator PG to read out stitch control signals from the static mamory ROM for the selected pattern.
Subsequently if the straight stitching is selected by manipulation of the pattern selecting device PS, the electric drive device DV drives the pulse motor 53 in dependence upon the control signals from the static memory ROM which is read out by the central processing unit PCU. As the result, the control lever 66 is turned by the pin 68 in the clockwise direction to the position as shown in FIG. 20 and the precededly selected zigzag stitching needle hole is reduced to a straight stitching one. In this instance, the pin 61 engages the region B of the control cam 59, and therefore the needle is shifted to the center position by way of the transmission rod 63. The needle hole replacing operation is finished when the pin 61 comes to engage the point (B1) of the control cam 59. This operation is, of couse, carried out after it is confirmed by the control circuit that the needle is positioned at the upper dead point thereof. According to the invention, it can be easily conceived that the other function, for example, an automatic thread cutting may be realized by providing an additional control lever such as 66 and also by providing an additional control cam such as the cam 59 so as to hold the needle position unchanged when the thread cutting operation is made. | A sewing machine including stitch forming device, electrically driven means for driving the needle and the feed dog, a static memory to control the electrically driven means and a pattern selecting arrangement. The electrically driven means comprise a pulse motor for controlling a horizontal feeding amount of the feed dog and a clutch solenoid operatively connected to a shaft of the pulse motor. The device is provided with a feed control arrangement having an operating member to actuate the position of the feed dog. The clutch solenoid is operatively connected to the operating member and is energized in response to a stitch signal from the static memory to define the position of the feed dog in accordance with a selected pattern. | 3 |
BACKGROUND OF THE INVENTION
Description of the Related Art
[0001] Polling is a term used in many technological areas to describe a process when one device makes an inquiry or communicates with a second device. Typically polling involves one device querying a number of other devices in a defined order. For example, in computer and communications networks, one computer may communicate with another computer or computers to accomplish a number of procedures. Typically the initiating computer (i.e., polling computer) will begin the polling process by communicating with a computer (i.e., polled computer) that receives the poll. The receiving computer will then respond to the poll or communication.
[0002] Polling may be used for a number of reasons. For example, polling is often used for troubleshooting in a communications network. One network device will simply communicate with the other network device(s) as a way of determining if all of the network device(s) are operational in the network. Should one device fail to respond to the poll, it may be an indication that the device is not operational.
[0003] Polling is used to perform network administrative procedures. In this scenario, one computer is in charge of polling other computers and communicating commands to perform various administrative procedures. For example, administrative procedures, such as backups and various types of updates, may be accomplished using a polling process.
[0004] Irrespective of the specific function accomplished during polling, conventional polling systems are typically configured in client-server or master-slave architecture. In each of these scenarios, the polling device (i.e., the device initiating a poll, inquiry, or communication) controls the polling process and the polled device (i.e., the device receiving and responding to the poll, inquiry, or communication) responds to the polling inquiry. The polling device typically has the process intelligence and manages errors during the polling process. The polled devices are often responsive devices although they may have varying levels of sophistication. The procedural logic is typically associated with the polling device. Therefore, the polling device determines, who is polled, how they are polled, and what happens as a result of the poll. In this scenario, the polled device serves as nothing more than a repository of information.
[0005] The flaw in this design is obvious; there is a single point of failure. Should the polling device fail, it puts at risk the procedures associated with the poll across the network. Therefore, a number of techniques have been implemented to address the single point of failure issue. Just about all of these techniques involve more complex polling procedures and architectures. For example, implementing a redundant polling device may supplement and avoid the single point of failure, however, as the number of polling devices increase, the complexity of the system increases, which also increases cost, troubleshooting time, etc.
[0006] Thus, there is a need for a cost-effective method and apparatus for performing polling in a network. There is a need for a method and apparatus for performing polling in a network that creates redundancy, but minimizes complexity.
SUMMARY OF THE INVENTION
[0007] In accordance with the teachings of the present invention, a method and apparatus is presented for performing polling. In accordance with the teachings of the present invention, clients are defined as polling devices and poll for information in a public or private network. The polled devices (i.e., servers) maintain the intelligence associated with the poll for each client. Therefore, although the polling device (i.e., client) performs the poll (i.e., initial communication or inquiry), the polled device includes the intelligence that controls and instructs the client on the various tasks that the client should perform.
[0008] In accordance with the teachings of the present invention, a client performs a first polling process to poll a polling server, the polling server receives the poll based on the clients use of the first polling process, the polling server then changes the polling process and directs or controls the client to perform a second polling process. It should be appreciated that a variety of clients may access the polling server and that the polling server specifically directs and controls each client individually. For example, the polling server may uniquely change the polling process of each client that accesses the polling server or the polling server may group clients and change the polling process associated with groups of clients.
[0009] In one embodiment, the clients access polling servers using a process. The process facilitates load balancing in the network. For example, in one embodiment, the clients generate a pseudo-random number and select a polling server based on the pseudo-random number. As such, polling network load is balanced across the network, since clients randomly access available polling servers. In addition, the polling servers may change and direct the random selection of polling servers. Therefore, dynamic real-time load balancing may be attained across the network. Lastly, the polling server may direct and/or control the clients in a way that separates and groups polling servers. For example, the polling server may direct the client to randomly select a polling server from a group of polling servers positioned behind a Virtual Private Network (VPN). As such, the network may be separated into subgroups to accommodate user purposes and then each subgroup may be dynamically load-balanced for polling and data traffic.
[0010] A method of polling, comprises the steps of receiving a poll from a client; performing at least one client specific task in response to receiving the poll from the client; and controlling client operations in response to performing the client specific task.
[0011] A method of polling comprises the steps of receiving a poll from a plurality of polling clients, each of the plurality of polling clients using a first polling process; performing a tasks associated with each of the plurality of polling clients in response to receiving the poll; and uniquely controlling each of the plurality of polling clients in response to performing the polling tasks.
[0012] A method of load balancing in a network, comprises the steps of receiving polling information from a client; directing the client to randomly select a polling data server in response to receiving the polling information; and effecting load-balancing across the network in response to directing the client to randomly select a polling data server.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 displays an architecture implemented in accordance with the teachings of the present invention.
[0014] FIG. 2 displays a flow diagram detailing a first method of polling implemented in accordance with the teachings of the present invention.
[0015] FIG. 3 displays a flow diagram detailing a second method of polling implemented in accordance with the teachings of the present invention.
[0016] FIG. 4 displays a flow diagram detailing a third method of polling implemented in accordance with the teachings of the present invention.
[0017] FIG. 5 displays a computer architecture implemented in accordance with the teachings of the present invention.
DETAILED DESCRIPTION
[0018] While the present invention is described herein with reference to illustrative embodiments for particular applications, it should be understood that the invention is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the present invention would be of significant utility.
[0019] In accordance with the teachings of the present invention, client machines poll polling-server machines. When the client machine contacts a specific polling machine, a set of tasks (i.e., methods) is performed. The tasks are the action items or functions associated with the specific client.
[0020] FIG. 1 displays a network architecture implemented in accordance with the teachings of the present invention. An administration client 100 is displayed. An end user operates the administration client 100 to configure the network, provide content to the network, etc. The administration client 100 may be implemented with a variety of technologies, such as a standard computer or as a computer network. The administration client 100 is in communication with a network 102 . The network 102 may be a public data network or a private data network. A variety of technologies may be used to implement the network 102 , such as packet-switched technology, circuit-switched technology, optical technology, wireless technology, etc.
[0021] A database 104 is in communication with the network 102 . The database 104 may be implemented as a single database, a distributed database, a database network cluster, etc. The database 104 stores network information about various components of the network shown in FIG. 1 . Administration servers 106 are in communication with the network 102 . The administration servers 106 include computers in the network used to administer the network 102 . The administration servers 106 may include a single database, a distributed database, a database network cluster, etc. Media data centers 108 and 112 are also in communication with the network 102 . The media data center (MDC_ 1 ) 108 and the media data center (MDC_N) 112 may each represent a plurality of media data centers. The media data centers ( 108 , 112 ) may be implemented as a database for storing information, storage media, a network cluster of databases, a network cluster or storage media.
[0022] Polling (i.e., requesting) clients 110 are shown in communication with the network 102 . Polling clients 110 include those clients that an end user operates to request content from the network 102 and/or poll the network 102 . Polling servers 114 are in communication with network 102 . The polling servers 114 may be implemented with hardware and/or software as a single database, multiple databases, single computer, network computers, etc. In one embodiment, the polling servers 114 receive polls from the polling clients 110 and respond to the polling clients 110 . It should be appreciated that while one polling server 114 is shown, polling servers 114 represent multiple polling servers.
[0023] FIG. 2 displays a flow diagram detailing a first method of polling implemented in accordance with the teachings of the present invention. FIG. 2 will be discussed in conjunction with FIG. 1 . At step 200 , polling clients 110 format polling packets that contain information that needs to be sent to polling servers 114 . In one embodiment, this information is sent in a web request.
[0024] A variety of different types of information is sent with a poll from the polling clients 110 to the polling servers 114 . Among the different types of information are: 1) the polling clients' 110 identification (ID), which may be in the form of an email address or may be a uniquely generated ID (i.e., 093b11e8-1dc4-4720-994f-ba90154dfdf2); 2) a list of companies that the polling clients 110 are associated with; 3) the current IP address of the polling clients 110 ; 4 ) a set of bit flags that tell the polling servers 114 how the polling clients 110 are connected to the Internet (through a LAN, Modem, etc.); 5) any “view events” that have taken place since the last poll (i.e., in one embodiment, “view events” represent the content a user operating the polling clients 110 has viewed, and which sub-sections within that content the polling clients 110 have viewed, along with the viewing duration for each subsection and a total time spent viewing the content); 6) flags that specify whether or not host software is currently installed, and if so, if it is currently running. In one embodiment, the software operating on the polling clients 110 includes: host software (i.e., which provides a user interface for the user to select and view content) and a networking component, which handles polling the polling servers 114 , downloading content, executing poll commands, etc; and 7) version information for both, the host software and the networking component.
[0025] In one embodiment, during polling, a web request (i.e., from polling clients 110 ) and response (i.e., from the polling server 114 ) is generated. For example, consider a web request:
[0000] http://www.google.com/search.cgi?q=foo&flaqs=1234;
[0026] and a response to such a request would be a web page:
<html> <head> <title>Google web page</title> </head> <body> ...........
In one embodiment, a poll is implemented as a web request, for example:
http://poll01.matcast.neVpoll.cgi?clientID=093b11e8-1dc4-4720-994f-ba90154dfdf2&company=ahalaa&lp=8497690
and, the response to this request may be the following:
[0027] p 24000
[0028] #
[0029] In one embodiment, the response is not an HTML document, but rather a series of commands. In our example, the “p 24000” is a specific response to the client to set the poll time to 24000 seconds (6.666 hours). The hash symbol is used to denote the end of the list of commands.
[0030] At 202 , the polling servers 114 accept these polls from polling clients 110 , and examine the client's record in the database 104 . In accordance with the teachings of the present invention, based on what the polling servers 114 retrieve from the database 104 (i.e., the unique instructions associated with the client), the polling servers 114 decide (i.e., the “logical component of the polling servers” 114 ) the tasks that will be performed for and by the polling clients 110 and which commands need to be sent to the polling clients 110 . In other words, the polling servers 114 operate to control the polling clients 110 . For example, the polling servers 114 send a response to the polling clients 110 . In one embodiment, a poll response is a set of commands (i.e., commands followed by an optional command parameters).
[0031] In accordance with the teachings of the present invention, the polling clients 110 poll the polling servers 114 . The polling servers 114 perform tasks (i.e., methods) that are specifically tailored for that polling client 110 . As mentioned previously, the polling servers 114 receive specific identifying information and/or instructions from the polling clients 110 . In response, the polling servers 114 may decide to do one or more of four fundamental tasks: 1) accept polls from new polling clients 110 and add them to the database 104 ; 2) send the polling clients 110 media packets (i.e., where to get new media); 3) manage “other activities” for that polling client 110 ; 4) update the database 104 with the most recent polling clients 110 activity information. Each of these categories of tasks is an independent process that may be implemented with a variety of technologies, such as active server pages.
[0032] One of the four fundamental tasks is accepting polls from the new polling clients 110 and adding them to the database 104 . New polling clients 110 are recognized since their ID does not already exist in the database 104 . As such, their polling information is used to create a new record in the database 104 for the polling clients 110 . The database 104 stores a moderate amount of information about each polling client 110 , including, but not limited to:
1. the user agent used during the poll; 2. the current version information for both, the host software and the networking component; 3. the first and last poll time (timestamp format); 4. the IP address that the polling clients 110 used during the last poll; 5. the media (i.e., content) scheduled to be delivered to the client; 6. the list of media that has already been sent to the client; 7. the client ID; 8. the companies that a client is associated with (American Airlines, etc.); 9. the client's connection type (i.e., LAN, Modem, etc.); 10. subscription information (if they are subscribed, when it expires, etc.); 11. which video codecs the client is scheduled to receive; 12. the complete set of view events recorded for the client since the last poll; 13. flags specifying whether or not the host software is still installed on the client, and if so, if it was currently running during the last poll; 14. etc.
For new polling clients 110 , the database 104 is populated with a minimal amount of information(i.e., as much of this information is available on the network 102 ). In one embodiment, only a small amount of this information must be present in the database 104 (i.e., just a client ID and the list of companies that the client is associated with) during operation.
[0047] In one embodiment, a special set of tasks is implemented for new polling clients 110 . Primarily, the polling clients 110 must be sent the latest video codecs (i.e., drivers that allow you to view various types of audio/video content), so that they can properly view the media and so that they can receive the media. These codecs are special—they are not treated like media content because the client must receive the codecs before it receives any media. However, media is not sent to the client in any particular order. Therefore, the binary data for these codecs is sent to the client as part of the polling response. This is done using an installation command whose parameter is a base64-encoded binary data for an installation package containing the video codecs.
[0048] A second task performed by the polling servers 114 includes sending media packets. Sending a client a media packet is another type of response to a poll. It is a set of responses from the polling servers 110 . Whether or not media is to be sent to a client (and if so, what media) is determined by querying the database 104 .
[0049] A third task includes managing activities for the client. Any command that the client should perform may be send from the polling servers 114 . In one embodiment, every response to a poll is a command or series of commands. In addition, commands can be sent individually or streamed together. For example, a single poll response could cause the client to receive ten pieces of media, change the client's poll time to thirty minutes, have it install a set of codecs and restart itself, all within in a single poll response. Each poll may be separated into individual polls, but a batch process may also be used.
[0050] The final of the four general tasks is updating the database 104 with the most recent client information. This last task is similar to adding new clients except that a record is not created, but instead we simply modify a few existing fields. In one embodiment, these fields include:
1. the time of the last poll; 2. the IP address and user agent used by the client during the last poll; 3. adding any view events sent by the client in the last poll; 4. updating the software version information for our software running on the client; 5. updating the client's connection type (modem, LAN, etc).
Along with these updates, the polling servers 114 also update the client's record in the database 104 with the latest information detailing what the polling servers 114 have done. For example, if the client is scheduled to receive a piece of content, then once that data has been sent to the client, that piece of content is removed from the database list of content scheduled to be delivered to the client.
[0056] As part of the polling process, the client can send back error information. If the client has had difficulty performing any of its tasks installing codecs, downloading media, or even connecting to the polling servers 114 , then the errors are accumulated on the client. Every time the client polls, these errors are sent along with the poll and the client purges its current list of errors. The polling servers 114 record these errors in the database 104 for subsequent troubleshooting. The database 104 is then updated.
[0057] At step 204 , the polling clients 110 receive the polling response from the polling servers 114 and act upon them. In one embodiment, every poll response includes a list of active polling servers 114 . The polling clients 110 store this information for future reference. When it comes time for the polling clients 110 to perform a poll, it consults its current list of polling servers 114 , and in accordance with the teachings of the present invention, randomly selects one from the list and polls that polling server 114 . If the poll fails, the address associated with the failed polling server 114 is removed from the polling clients' 110 local copy of the list and the polling clients 114 select another polling server 114 (i.e., at random) from the list. At step 206 , any errors are accumulated for future polls and if media is scheduled, then the polling clients 110 can begin to gradually download the media.
[0058] FIG. 3 displays a flow diagram detailing a second method of polling implemented in accordance with the teachings of the present invention. FIG. 3 will be discussed in conjunction with FIG. 1 . At step 300 , polling clients select polling servers and generate a poll using a first polling process. For example, polling clients 110 select polling servers, such as polling servers 114 , and generate a poll to polling servers 114 . In accordance with the teachings of the present invention, the polling clients 110 may select the polling servers using a static address provided to the polling clients 110 or the polling clients may use a random method to select polling servers 114 . When a static address is provided to the polling clients 110 , the polling clients 110 will poll the polling servers 114 identified by the static address. In an alternative embodiment, a plurality of addresses is provided to the polling client 110 . When a plurality of addresses is provided to the polling clients 110 , the polling clients 110 may use a variety of random methods to select polling servers 114 to poll. As such, polling is distributed across a number of different polling servers 114 and load balancing is accomplished across the network 102 . Once again, it should be appreciated that polling clients 110 represent many clients and polling servers 114 represents many polling servers.
[0059] In accordance with the teachings of the present invention, the polling clients 110 may be provided with a list of polling servers' addresses and perform a LIFO function to select a polling server 114 . In a second embodiment, the polling servers 114 may perform a FIFO function. In a third random method the polling client 110 may associated an index with each address of each polling server 114 and select a polling server 114 based on a pseudo-random number generation technique. For example, in one embodiment, the address is randomly selected by taking the modulus of the output of the pseudo-random number generator with the size of the list. Once again, with a plurality of polling clients 110 each using a random method to select a polling server 114 and randomly polling a polling server 114 based on the random method, load-balanced polling is accomplished across the network 102 shown in FIG. 1 .
[0060] The foregoing method of polling, in which a static address is provided to the client 110 and a polling server 114 is selected, may be considered a first polling process. In the alternative, the random method used to poll may be considered a first polling process. Further, a variety of alternative methods may be considered a first polling process. For example, polling clients 110 may be given a specific order that should be used to poll polling servers 114 . Polling clients 110 may be given directions to poll and then wait for a given time before issuing another poll. Polling clients 110 may be given initial directions to poll several polling servers 114 at the same time and then respond to the first response that is received. It should be appreciated that a variety of different permutations and combinations may be performed.
[0061] At 302 , the polling servers 114 accept these polls generated by polling clients 110 , and examine the polling clients' 110 records in the database 104 . In accordance with the teachings of the present invention, based on what the polling servers 114 retrieve from the database 104 (i.e., the unique instructions associated with the polling clients 110 ), the polling servers 114 decide (i.e., the “logical component of the polling servers” 114 ) the tasks that will be performed for and by the polling clients 110 and which commands need to be sent to the polling clients 110 . In other words, the polling servers 114 operate to control the polling clients 110 . For example, the polling servers 114 send a response to the polling clients 110 . In one embodiment, a poll response is a set of commands (i.e., commands followed by optional command parameters).
[0062] In accordance with the teachings of the present invention, the polling clients 110 poll the polling servers 114 . The polling servers 114 perform tasks (i.e., methods) that are specifically tailored for that polling client 110 . As mentioned previously, the polling servers 114 receive specific identifying information and/or instructions from the polling clients 110 . In response, at 304 , the polling servers 114 control and direct the polling clients 110 and change the first polling process to a second method of operation. The second method of operation may be a second polling process or some other second method of operation. In accordance with the teachings of the present invention, in a scenario where the polling clients 110 poll the polling servers 114 using a first polling process, the polling servers 114 may completely redirect the polling clients 110 to perform a second polling process immediately, on the next poll, or some time later. For example, the polling clients 110 may have a static address for a polling server 114 and just poll the polling server 114 the first time that the polling clients 110 poll the network 102 . The static method of polling would be the first polling process. The polling servers 114 may then provide the polling clients 110 with a list of addresses associated with polling servers 114 . The polling clients 110 may then use a random method of selecting a polling server 114 and a) immediately, randomly select a second polling server 114 and perform a poll, b) randomly select a polling server 114 at some time later and performing a poll, and/or c) randomly selecting a polling server 114 and on the next scheduled poll of the polling server 114 , performing a poll using the randomly selected polling server 114 . The method of randomly selecting a polling server 114 is a change to the first polling process (i.e., statically selecting a polling server 114 ). As such, the random method of polling is a second polling process.
[0063] In one embodiment, the polling servers 114 provide the polling clients 110 with several addresses of polling servers 114 and direct the polling clients 110 to randomly select a polling server 114 . The list of addresses in combination with the directions to randomly select addresses from the list for polling enables the polling servers 114 to control load balancing across the network 102 . For example, the polling servers 114 may provide the polling clients 110 with a list of polling servers 114 located in a VPN and direct the polling clients 110 to randomly select from the list of polling servers 114 in the VPN. As such, load balancing is accomplished across a subset of the polling servers 114 (i.e., poling servers in the VPN) in the network 102 . Using this foregoing method, the polling servers 114 may dynamically perform load shifting and load balancing across various parts of the network 102 . For example, polling clients 110 may pay for different levels of quality of service (QoS) and the polling clients 110 may load balance the entire network 102 so that polling clients 110 that require the highest levels of QoS use a group of low traffic polling servers 114 and polling clients 110 that require a lower level of QoS use a group of high traffic polling servers 114 . Using the foregoing technique, load balancing may be dynamically maintained so that regardless of the varying traffic demands in the network 102 , the high level QoS polling clients 110 are always receiving the best service and the lower level QoS polling clients 110 are always receiving a lesser service. Further, using the foregoing methods, load balancing and QoS can be dynamically changed in real-time.
[0064] It should be appreciated that a variety of combinations and permutations may be performed in accordance with the teachings of the present invention. For example, the polling clients 110 may poll polling servers 114 in a certain order, time schedule, etc. and then the polling servers 114 may respond changing the order, time schedule, etc. of polling after which, at 306 , the polling clients 110 poll polling servers 114 in a different order, time schedule, etc.
[0065] FIG. 4 displays a flow diagram detailing a third method of polling implemented in accordance with the teachings of the present invention. FIG. 4 will be discussed in conjunction with FIG. 1 . At 400 , the polling clients 110 sleep for a period of time. At step 402 , the polling clients 110 send a polling packet to the polling servers 114 . At 404 , the polling servers 114 receive the poll from the polling clients 110 and query the database 104 for client information. If the polling clients 110 are not found in the database 104 , at 408 , the polling servers 114 add the polling clients 110 information to the database 104 . At 410 , the polling clients 110 are sent a start-up packet through a polling connection. At 412 , the polling clients 110 receive and execute the start-up packet. At 414 , If the polling clients 110 are found in the database (i.e., 406 ) and new media is available for the polling clients 110 , then a media delivery packet is created for the polling clients 110 as stated at 416 . At 418 , the polling servers 114 send the latest polling clients' 110 information to the database 104 . At 420 , the polling clients 110 are sent a media delivery packet and at 422 , the polling clients download media and execute this process when the download is complete. At 414 , if there is no new media for the polling clients 110 , but there are other activities for the polling clients 110 (i.e., 424 ), the other activities packet is sent as stated at 426 . At 428 , the polling servers 114 send the latest polling clients' 110 information to the database 104 . At 430 , the polling servers 114 send the other activities packets to the polling clients 110 . At 430 , the polling clients 110 download media and execute the content when the download is complete (i.e., 432 ). If there are no other activities for the polling clients 110 , the polling servers 114 send the latest polling clients' 110 information to the database 104 as stated at 436 and the polling clients 110 are sent a null packet as stated at 434 .
[0066] FIG. 5 displays a computer hardware architecture implementing the teachings of the present invention. The computer 500 may be used to implement the client 100 , network 102 , database 104 , administration servers 106 , polling servers 114 , or a media data center 108 , 112 , or 114 of FIG. 1 . A central processing unit (CPU) 502 functions as the brain of the computer 500 . Internal memory 504 is shown. The internal memory 504 includes short-term memory 506 and long-term memory 508 . The short-term memory 506 may be a Random Access Memory (RAM) or a memory cache used for staging information. The long-term memory 508 may be a Read Only Memory (ROM) or an alternative form of memory used for storing information. Storage memory 520 may be any memory residing within the computer 500 other than internal memory 504 . In one embodiment of the present invention, storage memory 520 is implemented with a hard drive. A communication pathway 510 is used to communicate information within computer 500 . In addition, the communication pathway 510 may be connected to interfaces, which communicate information out of the computer 500 or receive information into the computer 500 .
[0067] Input devices, such as tactile input device, joystick, keyboards, microphone, communications connections, or a mouse, are shown as 512 . The input devices 512 interface with computer 500 through an input interface 514 . Output devices, such as a monitor, speakers, communications connections, etc., are shown as 516 . The output devices 516 communicate with computer 500 through an output interface 518 .
[0068] Thus, the present invention has been described herein with reference to a particular embodiment for a particular application. Those having ordinary skill in the art and access to the present teachings will recognize additional modifications, applications, and embodiments within the scope thereof.
[0069] It is, therefore, intended by the appended claims to cover any and all such applications, modifications, and embodiments within the scope of the present invention. | A method and apparatus for performing polling is presented. Polling servers include the intelligence and as such may control polling clients. What is polled, when it is polled and how it is polled is controlled by the polling server and may be dynamically changed and any time. As such, the polling server may dynamically reconfigure the polling process for a polling client. In one embodiment, the polling server directs and controls the polling client(s) in a manner that effects load-balancing in a network. | 7 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a three-dimensional image display device and a three-dimensional image display method and program for displaying a three-dimensional image enabling depth perception and produced from a plurality of images acquired by imaging a subject from different viewpoints.
[0002] Conventionally, a sense of depth is produced using a parallax caused by displaying a plurality of images having different lines of sight. Examples of methods for producing a sense of depth include a method (1) applying linear polarization to the left eye image and the right eye image in directions crossing each other at right angles and using polarized glasses, a method (2) whereby the left eye image and the right eye image are displayed alternately and viewed with glasses equipped with liquid crystal shutters synchronized with the display means, and a method (3) using red and blue light that are superposed on the left eye image and the right eye image, respectively, and glasses having red and blue color filters on the left and the right piece of glass.
[0003] Another method of producing a sense of depth to the naked eye is one whereby, for example, an image is cut into a plurality of strips and arranged alternately for the left and the right eye to view their respective images using a parallax barrier or a lenticular lens to enable depth perception.
[0004] As related to the present invention may be cited prior art literature JP 2009-239389 A and JP 2008-5203 A.
[0005] JP 2009-239389 A describes displaying a three-dimensional image in such a manner as to lessen a feeling of fatigue felt by the viewer in a case where a subject is imaged from different viewpoints to produce a plurality of images, from which those enabling depth perception are displayed, wherein complementary images having a smaller parallax than the parallax between the plurality of images are produced to gradually change the parallax of the three-dimensional images.
[0006] To solve a problem that the viewer is fatigued by a frequent change between a 2D and a 3D image, JP 2008-5203 A describes a display method wherein a 2D image is converted into a new 3D image or a 3D image is converted into a new 2D image, and these converted images are used when a change is made between 2D and 3D images to allow the change to take place gradually.
SUMMARY OF THE INVENTION
[0007] Three-dimensional moving images can relatively easily produce a sense of depth to the viewer because of the motion, but three-dimensional still images, when viewed individually, cannot effectively cause the viewer to perceive depth as compared with three-dimensional moving images. Particularly when depth perception is to be achieved with the naked eye, i.e., without the aid of, for example, polarized glasses, depth is yet more difficult to be perceived by the viewer.
[0008] In addition, when a planar image is displayed full-screen on a monitor and when the parallax between a plurality of images for displaying a three-dimensional image is great, the area enabling depth perception decreases as illustrated in FIG. 12B , and, as compared with a case where the parallax is small as illustrated in FIG. 12A , the displayed area grows smaller, which may cause a discomfort to the viewer.
[0009] Thus, an object of the present invention is to provide a three-dimensional image display device and a three-dimensional image display method and program capable of easily displaying a three-dimensional image by changing the pop-out amount thereof in an appropriate manner so that the viewer can readily perceive depth in the three-dimensional image and capable of enhancing the perceived depth.
[0010] In order to attain the object described above, the present invention provides a three-dimensional image display device for displaying a three-dimensional image enabling depth perception and produced from a plurality of images acquired by imaging a subject from different viewpoints, the three-dimensional image display device comprising:
[0011] a timer unit for setting and measuring a given time over which a pop-out amount of the three-dimensional image changes;
[0012] a pop-out amount change mode memory for storing information on a time-dependent change of the pop-out amount occurring over the given time;
[0013] a pop-out amount controller for producing the pop-out amount for each unit time based on a parallax between the plurality of images, the given time, and the time-dependent change information;
[0014] a changing image producer for producing a given number of pairs of pop-out amount changing images from the plurality of images according to a pop-out amount by the unit time;
[0015] a three-dimensional image producer for producing a corresponding pop-out amount changing three-dimensional image from the given number of pairs of pop-out amount changing images; and
[0016] a display controller for displaying the corresponding pop-out amount changing three-dimensional image on a monitor based on the given time measured by the timer unit and the unit time.
[0017] Also, it is preferred that the pop-out amount is changed so that a given region in the three-dimensional image is displayed with an enhancement applied to a greater extent than another region except for the given region.
[0018] Moreover, it is preferred that the plurality of images are larger than a screen of the monitor, and wherein the pop-out amount changing three-dimensional image is substantially as large as or larger than the screen of the monitor.
[0019] Also, it is preferred that the pop-out amount changes from a first predetermined level to at least a second predetermined level over the given time. Moreover it is preferred that the first predetermined level is zero.
[0020] Also, it is preferred that the pop-out amount is greater at the second predetermined level than at the first predetermined level.
[0021] Moreover, it is preferred that one or more of sound, light, and enhanced display are used to notify that the pop-out amount is at least at a third predetermined level.
[0022] Also, it is preferred that the pop-out amount is controlled based on the time-dependent change information that varies according to a kind of content of the plurality of images.
[0023] Moreover, it is preferred that the time-dependent change information is included in header information of the plurality of images.
[0024] Also, the present invention provides a three-dimensional image display method of displaying a three-dimensional image enabling depth perception and produced from a plurality of images acquired by imaging a subject from different viewpoints, the three-dimensional image display method comprising:
[0025] a time measuring step of setting and measuring a given time over which a pop-out amount of the three-dimensional image changes;
[0026] an information reading step of reading information on a time-dependent change of the pop-out amount occurring over the given time from a pop-out amount change mode memory;
[0027] a pop-out amount controlling step of producing the pop-out amount for each unit time based on a parallax between the plurality of images, the given time, and the time-dependent change information;
[0028] a changing image producing step of producing a given number of pairs of pop-out amount changing images from the plurality of images according to a pop-out amount by the unit time;
[0029] a three-dimensional image producing step of producing a corresponding pop-out amount changing three-dimensional image from the given number of pairs of pop-out amount changing images; and
[0030] a display controlling step of displaying the corresponding pop-out amount changing three-dimensional image on a monitor based on the measured time and the unit time.
[0031] Also, the present invention provides a non-transitory computer readable recording medium embodied with a program for causing a computer to execute the steps of the three-dimensional image display method described above.
[0032] According to the present invention, wherein the pop-out amount of a displayed three-dimensional image is changed as appropriate, the viewer can easily perceive depth in the three-dimensional image. Further, the present invention, wherein the perceived depth of a displayed three-dimensional image can be enhanced, enables display thereof with increased entertaining qualities.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a block diagram of a configuration of the three-dimensional image display device according to one embodiment of the present invention.
[0034] FIGS. 2A to 2D are graphs illustrating examples of time-dependent pop-out amount change information.
[0035] FIGS. 3A and 3B are views for explaining an example of processing for informing that the pop-out amount has exceeded a predetermined level.
[0036] FIGS. 4A and 4B are views for explaining another example of processing for informing that the pop-out amount has exceeded a predetermined level.
[0037] FIG. 5 is a flowchart illustrating an example of flow of operation performed by the three-dimensional image display device of the present invention.
[0038] FIG. 6 is a view for explaining an example of a time-dependent change from a planar image to a three-dimensional image.
[0039] FIG. 7 is a view for explaining an example of a time-dependent change from a three-dimensional image having a small pop-out amount to a three-dimensional image having a great pop-out amount.
[0040] FIG. 8 is a view for explaining an example of a table showing a relationship between kind of image content and time-dependent change information.
[0041] FIG. 9 is a flowchart showing an example of flow of processing for selecting an optimum time-dependent change information from the table.
[0042] FIGS. 10A and 10B are views for explaining an example where a three-dimensional image is not desirably displayed.
[0043] FIGS. 11A and 11B are views for explaining an example where a three-dimensional image is desirably displayed.
[0044] FIGS. 12A and 12B are views for explaining the relationship between a pop-out amount of a three-dimensional image and the resulting display thereof.
DETAILED DESCRIPTION OF THE INVENTION
[0045] The three-dimensional image display device for implementing the three-dimensional image display method of the present invention will be described in detail based on the preferred embodiments shown in the attached drawings.
[0046] FIG. 1 is a block diagram illustrating a block diagram illustrating a configuration of the three-dimensional image display device according to one embodiment of the present invention.
[0047] The three-dimensional image display device 10 illustrated in FIG. 1 comprises an operating button 12 , a medium R/W 14 , a CPU 16 , an internal memory 18 , a compressor/expander 20 , a frame memory 22 , a temporary storage 24 , a time controller 26 , a timer unit 28 , a pop-out amount change mode memory 30 , a pop-out amount controller 32 , an effect controller 34 , a display controller 36 , an LCD 38 , and a bus 40 . All these except the operating button 12 and the LCD 38 are connected via the bus 40 . The medium R/W 14 has a recording medium 42 inserted therein.
[0048] The operating button 12 is used by the user to perform various operations of the three-dimensional image display device 10 . The operating button 12 may be any known operating equipment including but not limited to a keyboard or a mouse or a touch panel permitting selection of a button displayed on the screen.
[0049] The recording medium 42 described later is inserted and connected to the medium R/W 14 to enter therein a pair of images for displaying a three-dimensional image (hereinafter referred to also as 3D image). The entered pair of images are outputted as 2D image data. The pair of images is acquired by imaging a subject from two different imaging points and thus has a parallax according to the difference between the imaging points. The pair of images, acquired from two imaging positions, i.e., from a left-side and a right-side position, is also referred to herein as a left image and a right image, respectively. Although the present invention produces a three-dimensional image from a pair of images according to this embodiment, a three-dimensional image may be produced from three or more images acquired from three or more imaging positions.
[0050] Further, the pair of images is not limited to a pair of images acquired as 3D images and may be a pair of images that are still images acquired by the user with a digital still camera or a digital video camera or still images obtained by processing still image data downloaded from a network.
[0051] The CPU 16 , together with the internal memory 18 described later, constitutes a changing image producer and a three-image producer. The CPU 16 receives information entered with the operating button 12 and controls various components among other functions.
[0052] The internal memory 18 is a memory used by the CPU 16 for computation and comprises a DRAM (Dynamic Random Access Memory). In the internal memory 18 , various programs are run and computation results are temporarily stored. Part of the internal memory 18 is constituted by a non-volatile memory (e.g., flash memory) to store, for example, programs.
[0053] The compressor/expander 20 expands entered 2D image data when it is compressed data and compresses image data when recording it in the recording medium 42 . For example, the compressor/expander 20 expands 2D image data compressed into the JPEG (Joint Photographic Experts Group) format to the bit map format or, conversely, compresses bit-map image data into the JPEG format.
[0054] The frame memory 22 stores display image (frame image) data and is inputted with pop-out amount changing three-dimensional image data produced by the three-dimensional image producer.
[0055] The temporary storage 24 buffers the pop-out amount changing three-dimensional image data stored in the frame memory 22 and temporarily stores frame image data of the pop-out amount changing three-dimensional images repeatedly displayed in the slide show.
[0056] The time controller 26 is inputted with the display time of the pop-out amount changing three-dimensional image displayed on the LCD 38 through the operating button 12 . The time controller 26 is inputted with, for example, the display time of one pop-out amount changing three-dimensional image in the slide show and the display time of the whole group of a plurality of kinds of pop-out amount changing three-dimensional images. An entered display time is outputted as display time information.
[0057] The timer unit 28 sets and measures a time over which the pop-out amount of a pop-out amount changing three-dimensional image is allowed to change. The time over which a pop-out amount is allowed to change (pop-out amount change time: t m ) is preferably set to a length of time allowing the viewer to easily perceive depth, say about 1 to 2 seconds. The timer unit 28 outputs the pop-out amount change time t m and a measured time.
[0058] The pop-out amount change mode memory 30 stores time-dependent-change information on the pop-out amount change taking place in the pop-out amount change time t m . The time-dependent pop-out amount change information may be, for example, changes represented by graphs shown in FIGS. 2A to 2D .
[0059] FIG. 2A is a graph showing an exponential increase of a pop-out amount Δ over the pop-out amount change time t m ; FIG. 2B is a graph showing a step-wise increase of the pop-out amount Δ over the pop-out amount change time t m . FIG. 2C is a graph showing an acute increase of the pop-out amount Δ to a threshold (Δ th in the drawing) over the pop-out amount change time t m ; FIG. 2D is a graph showing the pop-out amount Δ exponentially increasing to about a half of a maximum (Δ max in the drawing), then leveling off before exponentially increasing again to the maximum over the pop-out amount change time t m .
[0060] The pop-out amount controller 32 is inputted with 2D image data, the pop-out amount change time t m , and the time-dependent change information. The pop-out amount controller 32 calculates a parallax between a pair of images used when producing a 3D image from 2D image data and produces the pop-out amount Δ by unit time based on the pop-out amount change time t m and time-dependent change information. In other words, the pop-out amount controller 32 produces the pop-out amount Δ by unit time from graphs showing time-dependent change information as illustrated in FIGS. 2A to 2D and outputs the pop-out amount Δ.
[0061] The unit time is set to a value not greater than a value corresponding to a refresh rate of the monitor (LCD 38 ) so that the viewer does not sense flickers on the screen. With an NTSC monitor, for example, the refresh rate may be set to 60 Hz, and the unit time to 16.7 ms. The monitor may be of any scan mode and resolution as appropriate; it is preferable that the refresh rate is set to 60 Hz or more, the unit time to 16.7 ms or less, while the resolution may be arbitrary. A still higher refresh rate may be used such as, for example, 120 Hz for double speed drive and 240 Hz for quadruple drive as used in a liquid crystal television, when the device used for the monitor is capable of such high refresh rates. The scan mode used may be of progressive mode.
[0062] The changing image producer will now be described.
[0063] The changing image producer comprises the CPU 16 and the internal memory 18 . The changing image producer is inputted with 2D image data and the pop-out amount Δ by unit time. The changing image producer produces pairs of pop-out amount changing images by unit time. When, for example, the unit time is 16.7 ms and the pop-out amount change time t m is 1 second as in the above example, 60 pairs of pop-out amount changing images are produced.
[0064] These pairs of pop-out amount changing images are a plurality of new pairs of images of which the pop-out amount (parallax) Δ between the left image or the right image (pop-out amount Δ=0) of each pair of images and the pair of images constituting a 3D image, where Δ=y, meaning the images are two-dimensional, changes sequentially from 0 to y. Thus, a plurality of pairs of pop-out amount changing images based on which a 3D display is achieved are produced. The pop-out amount Δ may be allowed to grow greater than the pop-out amount of a 3D image produced from original 2D image data.
[0065] The three-dimensional image producer will now be described.
[0066] The three-dimensional image producer comprises the CPU 16 and the internal memory 18 as does the changing image producer. The three-dimensional image producer is inputted with pairs of pop-out amount changing images, performs conversion in accordance with the display mode, produces a pop-out amount changing three-dimensional image, and outputs the pop-out amount changing three-dimensional image data.
[0067] While the display mode depends on the LCD 38 , examples thereof include: (1) a parallax type or a lenticular lens type whereby images of pairs of the pop-out amount changing images are arranged alternately by line; (2) a liquid crystal shutter type whereby images of pairs of the pop-out amount changing images are displayed alternately and viewed with glasses equipped with liquid crystal shutters synchronized with the display means; (3) a polarized filter type whereby linear polarization is applied in directions crossing each other at right angles to images of pairs of the pop-out amount changing images, which are then superposed and viewed with polarized glasses; (4) an anaglyph type whereby red and blue light are superposed on images of pairs of the pop-out amount changing images, and the images are superposed and viewed with glasses having a red and a blue color filter provided on the left and the right piece of glass, respectively. Where the viewer does not keep his/her eyes on an image for an extended period of time as in the case of a digital photo frame, the parallax type or the lenticular lens type display mode enabling depth perception for the naked eye is preferred.
[0068] The effect controller 34 applies an effect to the pop-out amount changing three-dimensional images when the pop-out amount has reached or exceeded a predetermined level (third predetermined level). Examples of the effect that may be applied include: increasing and decreasing the pop-out amount, generating a sound, lighting an area around the subject where the pop-out amount has reached or exceeded a predetermined level, indicating an area where 3D-effect may be produced, displaying an indication that the 3D-effect changes depending on the direction in which the image is viewed, highlighting an area where 3D-effect is not readily recognized by lighting, applying 3D-effect only to a particular area, and changing the degree of the 3D-effect applied.
[0069] In an example of the effect whereby an area around a subject where the pop-out amount has reached or exceeded a predetermined level is caused to light, when the pop-out amount of a subject 70 as illustrated in FIG. 3A has reached or exceeded a predetermined level, an effect may be applied so that light 72 surrounds the subject 70 as illustrated in FIG. 3B . In an example of the effect whereby an area where 3D-effect may be produced is indicated, the effect may be applied so that a tree 74 illustrated in FIG. 4A is shown with light 76 surrounding the tree 74 as illustrated in FIG. 4B . Thus, even where a 3D-effect is not readily recognized, as in an area close to the edge of the screen, the viewer may be allowed to note that the pop-out amount is at least at a predetermined level.
[0070] The display controller 36 is inputted with the measured time, the unit time, and the pop-out amount changing three-dimensional image. Based on the measured time and the unit time, the display controller 36 reads corresponding pop-out amount changing three-dimensional image data from the frame memory 22 and outputs the data to the LCD 38 to display the pop-out amount changing three-dimensional image.
[0071] The LCD 38 is a monitor, a liquid crystal display capable of 3D display. The LCD 38 may be a liquid crystal display of, for example, parallax barrier type. The LCD 38 may use another 3D display mode. Where a large display device is used, the LCD 38 is not limited to a liquid crystal display and may be a plasma display or another type of display including a projector, provided that it is capable of 3D display.
[0072] Next, the operation of the three-dimensional image display device 10 of the invention for implementing the three-dimensional image display method will be described.
[0073] FIG. 5 is a flowchart illustrating an example of flow of operation of the three-dimensional image display method of the present invention.
[0074] First, in preparation, the recording medium 42 is provided by a person who installs the three-dimensional image display device 10 (hereinafter referred to as installer) having therein stored image data of a plurality of pairs of images for displaying a 3D image is provided and inserted into the medium R/W 14 .
[0075] When the three-dimensional image display device 10 is switched on, the number of images of a plurality of pairs of image data stored in the recording medium 42 are counted, and the number of images M is set to N max . The counter (count) N is initialized to “1” (step S 10 ).
[0076] The installer uses the operating button 12 to enter the pop-out amount changing three-dimensional image display time, which may be, for example, a display time of one pop-out amount changing three-dimensional image in the slide show and a display time of the whole group of the plurality of kinds of pop-out amount changing three-dimensional images i.e., not the complemented pop-out amount changing three-dimensional images but the original images, in the time controller 26 , and the display time is outputted as display time information.
[0077] The display time of one pop-out amount changing three-dimensional image may be designated directly or obtained from the display time and the number of images of the whole group of images. In lieu of the installer entering the data, preset defaults may be used. For example, the display time of one pop-out amount changing three-dimensional image may be preset to 10 seconds.
[0078] Subsequently, a pair of images for a first (Nth) image are read via the medium R/W 14 from the recording medium 42 and outputted as 2D image data (step S 12 ). Now, the 2D image data is entered in the display controller 36 , and the left image or the right image of the 2D image data is displayed on the LCD 38 for the installer to check the image.
[0079] Next, the installer uses the operating button 12 to select or enter the time for the pop-out amount of the first pop-out amount changing three-dimensional image to reach or exceed a predetermined level, i.e., the pop-out amount change time t m (step S 14 ). The selected or entered pop-out amount change time t m is entered in the timer unit 28 and set. The pop-out amount change time t m may be a preset default, say 2 seconds.
[0080] With the pop-out amount change time t m set, the installer uses the operating button 12 to select a mode in which the pop-out amount is changed, i.e., time-dependent change information (step S 16 ), whereupon corresponding time-dependent change information is read from the pop-out amount change mode memory 30 and entered in the pop-out amount controller 32 and set (step S 18 ). The time-dependent change information of the pop-out amount Δ as illustrated in FIGS. 2A to 2D is selected. A default may be set; time-dependent change information showing a pop-out amount increasing exponentially as illustrated in FIG. 2A , for example, may be set as a default.
[0081] With the time-dependent change information set, first 2D image data and the pop-out amount change time t m are entered in the pop-out amount controller 32 . The pop-out amount controller 32 calculates the parallax between the left image and the right image constituting a 3D image from 2D image data, produces the pop-out amount Δ by unit time based on the pop-out amount change time t m and the time-dependent change information, and outputs the pop-out amount Δ.
[0082] The pop-out amount Δ by unit time is entered in the changing image producer, where pairs of pop-out amount changing images by unit time, i.e., a left and a right image constituting each of 3D images for each unit time (a pair of image), are produced and outputted.
[0083] The pairs of pop-out amount changing images by unit time are entered in the three-dimensional image producer. The pairs of pop-out amount changing images by unit time undergo conversion according to the display mode of the LCD 38 , the pop-out amount changing three-dimensional image by unit time is produced, and all the pop-out amount changing three-dimensional images for the pop-out amount change time t m , i.e., pop-out amount changing three-dimensional image data corresponding to one image is outputted (step S 20 ).
[0084] When an effect is applied to the pop-out amount changing three-dimensional image data, the pop-out amount changing three-dimensional image data is entered in the effect controller 34 . The effect controller 34 applies an effect to the pop-out amount changing three-dimensional image data and outputs the data with the effect applied. The effects applied by the effect controller 34 include production of sound and lighting of an area around a subject where the pop-out amount has reached or exceeded a predetermined level.
[0085] The frame memory 22 temporarily stores pop-out amount changing three-dimensional image data or pop-out amount changing three-dimensional image data to which an effect has been applied. The same data is temporarily buffered in the temporary storage 24 . The pop-out amount changing three-dimensional image data of the whole group of images or the pop-out amount changing three-dimensional image data to which an effect has been applied is buffered in the temporary storage 24 and sequentially written back into the frame memory 22 again during the slide show.
[0086] The measured time and the unit time outputted from the timer unit 28 are inputted to the display controller 36 , whereupon, based on the measured time and the unit time, corresponding pop-out amount changing three-dimensional image data or pop-out amount changing three-dimensional image data to which an effect has been applied is read from the frame memory 22 and sequentially outputted from the LCD 38 as display image data to display the pop-out amount changing three-dimensional image. Thus, one 3D image is displayed as its pop-out amount changes (step S 22 ).
[0087] When a first pop-out amount changing three-dimensional image (i.e., display image) is displayed, the count N of the counter is compared with N max (step S 24 ) and, when the count N is smaller than N max (“N” in step S 24 ), N is increased by 1 increment (step S 26 ), whereupon the procedure returns to step S 12 , where the next one pair of images undergo the same processing. When the count N is equal to N max (“Y” in step S 24 ), the processing ends.
[0088] Upon termination of the processing in the flowchart shown in FIG. 5 , the temporary storage 24 has the pop-out amount changing three-dimensional image data corresponding to all the 2D image data buffered therein.
[0089] Subsequently, the installer uses the operating button 12 to give a slide show start instruction, whereupon corresponding pop-out amount changing three-dimensional image data is read by the display controller 36 based on the measured time and the unit time from the frame memory 22 and sequentially outputted as display image data to the LCD 38 in order to display the pop-out amount changing three-dimensional image.
[0090] Now, when Nth pop-out amount changing three-dimensional image data is read from the frame memory 22 , (N+1)th (first when N=N max ) pop-out amount changing three-dimensional image data is written back into the frame memory 22 from the temporary storage 24 . Therefore, when the pop-out amount changing three-dimensional image data is read the next time by the display controller 36 from the frame 22 , (N+1)th (first, when N=N max ) pop-out amount changing three-dimensional image data is read. Accordingly, a plurality of three-dimensional images with changing pop-out amount Δ are repeatedly displayed on the LCD 38 in the slide show.
[0091] The change in pop-out amount will now be described referring to specific examples.
[0092] First, a slide show where the time-dependent change information shown in FIG. 2D is selected will be described referring to FIGS. 6 and 7 . In the explanation to follow, the pop-out amount changing three-dimensional image is also referred to simply as 3D image.
[0093] FIG. 6 illustrates a change from a state where the pop-out amount Δ=0 (first predetermined level), that is, where the left image or the right image of 2D image data is displayed and, through a state where the pop-out amount Δ=a, to a state where the pop-out amount Δ=b, that is, a 3D image is displayed, a and b being a second predetermined level. When the pop-out amount Δ=0, a background 50 and a person 52 a are both planar images, that is, they do not project forward. The pop-out amount Δ increases exponentially according to the graph of FIG. 2D until it temporarily levels off at Δ=a. In other words, the person 52 a becomes a 3D image that pops out as a person 52 b . The pop-out amount Δ thereafter increases again exponentially before reaching Δ=b. In other words, the person 52 b becomes a 3D image that further pops out as a person 52 c . In the process, the background 50 remains unchanged in dimensions, making the time-dependent change in pop-out amount the more easier to perceive.
[0094] FIG. 7 illustrates a change in pop-out amount Δ from a state where the pop-out amount Δ is small (Δ=a) and, through a state where the pop-out amount Δ=b, to a state where the image is a 3D image with a pop-out amount of Δ=c. Thus, the slide show may start with a display image that is a 3D image having a small pop-out amount Δ in lieu of a planar image, changing into a 3D image having a great pop-out amount L.
[0095] Next, a selection of time-dependent change information representing an optimum pop-out amount according to the content or imaging mode of a plurality of images (pairs of images) is described referring to FIGS. 8 and 9 .
[0096] FIG. 8 illustrates an example of a table correlating information on imaging mode used to acquire a pair of images to time-dependent change information.
[0097] Image data acquired by, for example, a digital camera often contains header information in the form of Exif (exchangeable image file format). Because Exif data includes imaging mode information, Exif data may be used to automatically select time-dependent change information on a pair of images (2D image data) for a 3D image.
[0098] To select time-dependent change information according to the imaging mode, the step S 16 in the flowchart shown in FIG. 5 is replaced by the flowchart shown in FIG. 9 . Selection of time-dependent change information according to the imaging mode is now described referring to the flowchart shown in FIG. 9 .
[0099] First, Exif data including information on the imaging mode is read from 2D image data in step S 30 . The imaging mode information is extracted from the Exif data and noted in step S 32 , a table stored in, for example, the internal memory 18 is read in step S 34 , and according to the table, time-dependent change information is set in step S 36 .
[0100] According to the example shown in FIG. 8 , when the imaging mode contained in the Exif data is “macro,” time-dependent change information No. 4 or time-dependent change information shown in FIG. 2C is selected, so that the image, which is a close-up shot, may be displayed with an enhancement. When the imaging mode is “landscape,” time-dependent change information No. 3 or time-dependent change information shown in FIG. 2D is selected, so that the image may be displayed with a gradual change in perceived depth. When the imaging mode contained in the Exif data is “sport,” time-dependent change information No. 2 or time-dependent change information shown in FIG. 2B is selected, so that the image may be displayed with an emphasis placed on movement. When the imaging mode is “person,” time-dependent change information No. 1 or time-dependent change information shown in FIG. 2A is selected, so that the image may be displayed with a gradual change in perceived depth.
[0101] Displaying an image on the LCD 38 will now be described.
[0102] FIG. 10A illustrates a state where the pop-out amount Δ=0, that is, where the left image or the right image of 2D image data (2D image) is displayed on the LCD 38 . A 2D image 80 a is displayed in substantially the same dimensions as a frame 82 of the LCD 38 . Should the pop-out amount Δ having such dimensions be increased until a 3D image 80 b is displayed, the area thereof permitting depth perception decreases to a size smaller than the display frame 82 . For the 3D image 80 b to have substantially the same size as the display frame 82 requires enlargement processing, which, implemented simultaneously as the 2D image 80 a changes to the 3D image 80 b , could cause discomfort to the viewer. Conversely, should the enlargement processing not be implemented, an area would be produced between the display frame 82 and the 3D image 80 b , where depth perception is impossible, impairing the look of the image.
[0103] Therefore, as illustrated in FIG. 11A , when a 2D image 84 a is displayed so as to be larger than the display frame 82 first, so that part of the 2D image 84 a is outside of the display frame 82 , increasing the pop-out amount Δ does not cause a 3D image 84 b to be smaller than the display frame 82 as illustrated in FIG. 11B . Thus, the area of the image visible to the viewer as defined by the display frame 82 remains unchanged so that the viewer may see the 3D image without feeling discomfort. Moreover, there is produced no area where depth perception is impossible.
[0104] The three-dimensional image display device of the present invention, wherein the pop-out amount of a displayed three-dimensional image is changed as appropriate, enables the viewer to easily recognize the three-dimensional image. Further, the three-dimensional image display device of the present invention, wherein the perceived depth of a displayed three-dimensional image can be enhanced, is capable of displaying images with increased entertaining qualities.
[0105] Further, according to the present invention, displaying a planar image so as to be larger than the display frame of the monitor first prevents occurrence of an area where depth perception is impossible as the pop-out amount is increased and thus obviates the necessity of enlarging the image as the pop-out amount is increased, thereby allowing the viewer to see the three-dimensional image without feeling discomfort.
[0106] Further, because the image is allowed to change gradually, the strain on the viewer's eyes can be lessened.
[0107] While a digital photo frame is described by way of example in the above embodiment, the invention is not limited thereto. Where glasses are used to view an image on a large-screen television, for example, the effect such as pop-out amount and other effects may be applied to a degree that may vary depending on the viewer, or a still 3D image stored in a cloud data home server may be viewed.
[0108] Further, the time-dependent change information may be included in the header information.
[0109] According to the invention, the three-dimensional image display program may be one for causing a computer to execute the steps of the three-dimensional image display method described above or one for causing a computer to function as individual means for executing the steps of the three-dimensional image display method, or a program for causing a computer to function as individual means constituting the above three-dimensional image display device.
[0110] Further, according to the present invention, the three-dimensional image display program may be configured as a computer-readable program or a computer-readable memory.
[0111] While the three-dimensional image display device and the three-dimensional image display method and program according to the present invention have been described above in detail, the present invention is by no means limited to the foregoing embodiments, and various improvements and modifications may be made without departing from the spirit of the present invention. | A three-dimensional (3D) image display device enables easy recognition of a 3D image by appropriately changing the popout amount of a 3D image. The display device includes a timer setting and measuring a given time over which the popout amount of a 3D image changes, a popout amount change mode memory storing information on time dependent change of the popout amount occurring over the given time, a popout amount controller producing the popout amount for each unit time based on parallax between a plurality of images, the given time, and the time dependent change information, a changing image producer producing pairs of popout-amount-changing images from the plurality of images according to a popout amount by the unit time, a 3D image producer producing a corresponding popout-amount-changing 3D image, and a display controller. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims priority under 35 U.S.C. 119 from Taiwan Patent Application No. 103126106 filed on Jul. 30, 2014, which is hereby specifically incorporated herein by this reference thereto.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an air filter, especially to an air filter for filtering suspended particles from air.
2. Description of the Prior Arts
An air filter is a device for filtering suspended particles from air, and is usually installed in a ventilation system of a building, an air compressor, or an engine of a vehicle. The conventional air filter such as an air cleaner disclosed in U.S. Pat. No. 6,190,432 as shown in FIG. 8 comprises a housing 91 , a filter core 92 and a sealing system 93 . The housing 91 has a first housing 911 and a second housing 912 . The first and second housings 911 , 912 are assembled together, and an accommodating space is formed between the first and second housings 911 , 912 . The first housing 911 has an outlet 914 communicating with the accommodating space. The second housing 912 has an inlet 913 communicating with the accommodating space.
With reference to FIGS. 8 to 10 , the filter core 92 is mounted in the accommodating space and has a wavy filtering sheet 922 and a flat filtering sheet 921 , both for filtering suspended pollutants. The wavy filtering sheet 922 and the flat filtering sheet 921 are rolled into a cylinder and are alternately stacked to form multiple layers of the wavy filtering sheet 922 and layers of the flat filtering sheet 921 . Thus, two surfaces of each layer of the wavy filtering sheet 922 are respectively flush with two adjacent layers of the flat filtering sheet 921 . Multiple channels 923 A, 923 B are formed between each layer of the wavy filtering sheet 922 and the two adjacent layers of the flat filtering sheet 921 A, 921 B. An end sealing adhesive layer 924 A is adhered between each layer of the wavy filtering sheet 922 at the side adjacent to the inlet 913 and one of the layers of the flat filtering sheet 921 A that are adjacent to said layer of wavy filtering sheet 922 . Thus, the channels 923 A between said layer of the wavy filtering sheet 922 and said layer of the flat filtering sheet 921 A are sealed at the side adjacent to the inlet 913 . Another end sealing adhesive layer 924 B is adhered between said layer of the wavy filtering sheet 922 at the side adjacent to the outlet 914 and the other layer of the flat filtering sheet 921 B that is adjacent to said layer of the wavy filtering sheet 922 . Thus, the channels 923 B between said layer of the wavy filtering sheet 922 and said layer of the flat filtering sheet 921 B are sealed at the side adjacent to the outlet 914 . As a result, the air to be filtered enters the cylinder-rolled filter core 92 from the inlet 913 of the second housing 912 , and then enters channels 923 B, which are not sealed at the side adjacent to the inlet 913 . Afterwards, the air axially moves to the other end of the channels 923 B, and is unable to flow out from the filter core 92 due to the end sealing adhesive layer 924 B. Thus, the air would pass through the layer of the wavy filtering sheet 922 to arrive at another channels 923 A, such that the air can flow out from the filter core 92 to arrive at the outlet 914 . When the air passes through the layer of the wavy filtering sheet 922 , the wavy filtering sheet 922 filters the suspended particles from the air to clean the air. In addition, the air may pass through the layer of the flat filtering sheet 921 B to arrive at another channel, and said layer of the flat filtering sheet 921 B also can filter the suspended particles from the air.
With reference to FIG. 8 , the sealing system 93 has an annular frame 931 and a seal member 932 . The annular frame 931 is mounted around the filter core 92 in an end adjacent to the outlet 914 . The seal member 932 is mounted around the annular frame 931 in an end adjacent to the outlet 914 , and transversely abuts an inner wall of the first housing 911 . The seal member 932 is made of pressable and resilient material, and an original outer diameter of the seal member 932 is bigger than an inner diameter of the first housing 911 at a position corresponding to the seal member 932 . The seal member 932 is pressed transversely to transversely and tightly abut the inner wall of the first housing 911 , thereby transversely sealing a gap between the filter core 92 and the first housing 911 . Accordingly, the air to be filtered must pass through the filter core 92 to arrive at the outlet 914 .
However, the conventional air filter has the following shortcomings.
First, the sealing system 93 seals the gap between the filter core 92 and the first housing 911 by transversely compressing the seal member 923 , and thus the outer diameter of the seal member 923 is bigger than the inner diameter of the corresponding position of the first housing 911 as mentioned above. Accordingly, installing the sealing system 93 into the first housing 911 is difficult, since the user has to apply much physical force to push the sealing system 93 into the first housing 911 .
Second, with reference to FIGS. 9 and 10 , the conventional wavy filtering sheet 922 and the flat filtering sheet 921 are adhered to each other by adhesives 925 . The adhesives 925 are spread on a surface of the flat filtering sheet 921 and extended along an elongated side of the flat filtering sheet 921 . Since the wavy filtering sheet 922 undulates as a wave, the flat filtering sheet 921 only adheres to a small part of peaks of the wavy filtering sheet 922 , and thus the adhered area between the flat filtering sheet 921 and the wavy filtering sheet 922 are too small to securely connect the filtering sheets 921 , 922 to each other. Besides, the adhesives 925 are spread between any two peaks, and thus occupy a part of the space of the channels 923 A, 923 B, thereby interfering with the flowing of the air. In addition, since the adhesives 925 are spread on only one surface of the flat filtering sheet 921 , each layer of the wavy filtering sheet 922 is only adhered to one of the layers of the flat filtering sheet 921 B, and is not adhered to the other layer of the flat filtering sheet 921 B. As a result, the connection between the flat filtering sheet 921 and the wavy filtering sheet 922 is not strong enough. After in use for a period of time, the wavy filtering sheet 922 and the flat filtering sheet 921 may have stained with suspended particles, which lower the filtering efficiency. Therefore, to clean the wavy filtering sheet 922 and the flat filtering sheet 921 , clean air is blown into the filtering core from the outlet 914 . When the clean air passes through the wavy filtering sheet 922 and the flat filtering sheet 921 in a reverse direction, the air brings the stained suspended particles out of the filtering sheets 921 , 922 , and the air is blown out of the inlet 913 together with the suspended particles. However, the connection between the flat filtering sheet 921 and the wavy filtering sheet 922 is not strong enough, and there is no annular frame 931 in an end adjacent to the inlet 913 to axially abut the filter core 92 . Consequently, as the air blows, the layers of the wavy filtering sheet 922 and the flat filtering sheet 921 in the center of the filter core 92 may separate from each other and axially protrude out along the blowing direction of the air, which causes the filter core 92 to be dysfunctional.
Third, with reference to FIG. 8 , as mentioned above, the annular frame 931 axially abuts and fixes the filter core 92 . The annular frame 931 has multiple connecting ribs 9311 . The connecting ribs 9311 are transversely connected to an inner wall of the annular frames 931 , and axially abut the filter core 92 . However, the connecting ribs 9311 also block the channels of the filter core 92 at the abutment position of the connecting ribs 9311 , and thus the air flow is interfered.
To overcome the shortcomings, the present invention provides an air filter to mitigate or obviate the aforementioned problems.
SUMMARY OF THE INVENTION
The main objective of the present invention is to provide an air filter that has an easily-installed filter core.
The air filter has a housing, a filter core, a resilient abutting element, a sleeve, a threaded rod bracket, a threaded rod, and a nut. The housing has an accommodating space, an inlet, an outlet, and a first stepped surface. The inlet and the outlet communicate with the accommodating space. The first stepped surface is formed annularly around an inner wall of the housing. The filter core is mounted in the accommodating space of the housing, and has a through hole. The through hole is formed axially through a center of the filter core. An outer diameter of the filter core is bigger than an inner diameter of an inner periphery of the first stepped surface of the housing. The resilient abutting element is annularly formed on a periphery of an end surface of the filter core that is adjacent to the outlet, transversely and axially wraps said periphery, and axially abuts the first stepped surface of the housing. The sleeve is mounted in the through hole of the filter core, and is adhered to a hole wall of the through hole. The threaded rod bracket is mounted securely in the accommodating space of the housing, and is disposed between the filter core and the outlet. The threaded rod is mounted securely on the threaded rod bracket, and is axially mounted through the sleeve. The nut is mounted around and is screwed on the threaded rod, axially abuts the sleeve in a direction toward the outlet, such that the resilient abutting element axially and tightly abuts the first stepped surface of the housing via the sleeve and the filter core to axially seal a gap between the first stepped surface and the filter core.
The axial sealing is achieved by axially compressing the resilient abutting element, such that the user does not have to apply much physical effort to compress the resilient abutting element. The user can easily push the filter core into the housing, and then rotates and tightens the nut, which can axially and indirectly compress the resilient abutting element. It is easy to apply force on rotating the nut, and better still, the nut can be rotated by an electric tool, which further facilitates the convenience in assembling the filter core into the housing. In addition, the nut only abuts the sleeve, and the threaded rod bracket does not abut the filter core. Therefore, two axial end surfaces of the filter core are almost completely unblocked, thereby ensuring the air can smoothly pass through the filter core.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an air filter in accordance with the present invention;
FIG. 2 is an exploded perspective view of the air filter in FIG. 1 ;
FIG. 3 is a side view in partial section of the air filter in FIG. 1 ;
FIG. 4 is an enlarged side view in partial section of a resilient abutting element of the air filter in FIG. 1 ;
FIG. 5 is an enlarged side view in partial section of a nut of the air filter in FIG. 1 ;
FIG. 6 is a partial operational perspective view of a filter core of the air filter in FIG. 1 , showing the filter core expanded;
FIG. 7 is an operational side view in partial section of the filter core of the air filter in FIG. 1 , showing the filter core expanded;
FIG. 8 is a side view in partial section of a conventional air filter in accordance with the prior art;
FIG. 9 is a perspective view of a filter core of the air filter in FIG. 8 ; and
FIG. 10 is a partial operational perspective view of the filter core of the air filter in FIG. 8 , showing the filter core expanded.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIGS. 1 and 2 , an air filter in accordance with the present invention comprises a housing 10 , a filter core 20 , a resilient abutting element 30 , a sleeve 40 , a threaded rod bracket 50 , a threaded rod 60 , a nut 70 , and a spacer 80 .
With reference to FIGS. 1 to 3 , the housing 10 has an accommodating space, an inlet 11 , an outlet 12 , a first stepped surface 13 , and a second stepped surface 14 . The inlet 11 and the outlet 12 communicate with the accommodating space. The first stepped surface 13 and the second stepped surface 14 are formed annularly around an inner wall of the housing 10 . The second stepped surface 14 is disposed between the first stepped surface 13 and the outlet 12 . An inner diameter of an inner periphery of the second stepped surface 14 is smaller than an inner diameter of an inner periphery of the first stepped surface 13 as shown in FIG. 3 . In a preferred embodiment, an inner diameter of the housing 10 remains unchanged from the first stepped surface 13 to the inlet 11 . A fixing bracket 15 is mounted securely on an outer wall of the housing 10 , is made of a bent elongated sheet, and has two elongated holes 151 formed through the fixing bracket, thereby facilitating convenience in assembling the fixing bracket on another object.
The filter core 20 is mounted in the accommodating space of the housing 10 and has two axial end surfaces and a through hole 26 . The through hole 26 is formed axially through a center of the filter core 20 . With reference to FIGS. 6 and 7 , the filter core 20 has a wavy filtering sheet 22 , a flat filtering sheet 21 , multiple adhesives 25 , and two end sealing adhesive layers 24 A, 24 B. The wavy filtering sheet 22 and the flat filtering sheet 21 are for filtering suspended pollutants, are rolled into a cylinder, and are alternately stacked to form multiple layers of the wavy filtering sheet 22 and layers of the flat filtering sheet 21 . Thus, two surfaces of each layer of the wavy filtering sheet 22 are respectively flush with two adjacent layers of the flat filtering sheet 21 . Multiple channels 23 A, 23 B are formed between each layer of the wavy filtering sheet 22 and the two adjacent layers of the flat filtering sheet 21 A, 21 B. The adhesives 25 are respectively spread on the two surfaces of each layer of the wavy filtering sheet 22 , and are respectively and axially spread along peaks of the surfaces of said layer of the wavy filtering sheet 22 , to be respectively adhered securely with the two adjacent layers of the flat filtering sheet 21 A, 21 B. One of the end sealing adhesive layers 24 A is adhered between each layer of the wavy filtering sheet 22 at the side adjacent to the inlet 11 and one of the layers of the flat filtering sheet 21 A that are adjacent to said layer of the wavy filtering sheet 22 . Thus, the channels 23 A between said layer of the wavy filtering sheet 22 and said layer of the flat filtering sheet 21 A are sealed at the side adjacent to the inlet 11 . The other end sealing adhesive layer 24 B is adhered between said layer of the wavy filtering sheet 22 at the side adjacent to the outlet 12 and the other layer of the flat filtering sheet 21 B that is adjacent to said layer of the wavy filtering sheet 22 . Thus, the channels 23 B between said layer of the wavy filtering sheet 22 and said layer of the flat filtering sheet 21 B are sealed at the side adjacent to the outlet 12 . In a preferred embodiment, the adhesives 25 and the end sealing adhesive layers 24 A, 24 B are preferably, but not limited to, hot-melt adhesives or Polyurethane (PU) structural adhesives. The flat filtering sheet 21 A, 21 B and the wavy filtering sheet 22 do not need to be pre-heated when adhered by hot-melt adhesives or Polyurethane structural adhesives, thereby facilitating convenience in manufacturing the filter core 20 . With reference to FIGS. 3 and 4 , an outer diameter of the filter core 20 is bigger than the inner diameter of the inner periphery of the first stepped surface 13 of the housing 10 , and the filter core 20 protrudes out of the inlet 11 of the housing 10 .
With reference to FIGS. 2 to 4 , the resilient abutting element 30 is annularly formed on a periphery of the end surface of the filter core 20 that is adjacent to the outlet 12 , transversely and axially wraps said periphery as shown in FIG. 4 , and axially abuts the first stepped surface 13 of the housing 10 . In a preferred embodiment, an outer diameter of the resilient abutting element 30 is smaller than the inner diameter of the housing 10 from the first stepped surface 13 to the inlet 11 , such that a transverse gap is formed between the resilient abutting element 30 and the inner wall of the housing 10 at a position corresponding to the resilient abutting element 30 as shown in FIG. 4 . In a preferred embodiment, the resilient abutting element 30 is made of Polyurethane directly foaming on the periphery of the filter core 20 . Preferably, a liquid colloid is filled by a mold into gaps between structure fibers of the filtering sheets 21 , 22 of the filter core 20 , and then the liquid adhesive is solidified to form the resilient abutting element 30 . But the resilient abutting element 30 is not limited by the manufacturing method mentioned above, and also can be made by other manufacturing methods or other resilient materials, such as rubber and silica gel. In a preferred embodiment, an axial thickness of the resilient abutting element 30 protruding out of the end surface of the filter core 20 that is adjacent to the outlet 12 ranges, but is not limited to, from 5 mm to 10 mm, preferably 5 mm, and is not altered with variations of the outer diameter or an axial length of the filter core 20 . In a preferred embodiment, a transverse thickness of the resilient abutting element 30 protruding out of an outer wall of the filter core 20 is, but not limited to, 2.5 mm, and is not altered with variations of the outer diameter or the axial length of the filter core 20 .
With reference to FIGS. 2, 3 and 5 , the sleeve 40 is mounted in the through hole 26 of the filter core 20 , and is adhered to a hole wall of the through hole 26 . Two ends of the sleeve 40 are respectively aligned with the end surfaces of the filter core 20 .
With reference to FIGS. 2 and 3 , the threaded rod bracket 50 is mounted securely in the accommodating space of the housing 10 , and is disposed between the filter core 20 and the outlet 12 . In a preferred embodiment, the threaded rod bracket 50 is an elongated sheet, and two ends of the elongated sheet are bent toward the outlet 12 to be axially welded securely to the second stepped surface 14 of the housing 10 . A gap is formed between a middle of the elongated sheet and the filter core 20 .
With reference to FIGS. 2, 3 and 5 , the threaded rod 60 is welded securely to a middle of the threaded rod bracket 50 , is axially mounted through the sleeve 40 , and protrudes out of the end of the sleeve 40 that is adjacent to the inlet 11 . In a preferred embodiment, outer threads 61 of the threaded rod 60 are formed only on a part of an outer wall of the threaded rod 60 that is adjacent to the end of the threaded rod 60 , rather than all over the outer wall of the threaded rod 60 .
The nut 70 is mounted around and is screwed on the threaded rod 60 , axially abuts the sleeve 40 in a direction toward the outlet 12 , such that the resilient abutting element 30 axially and tightly abuts the first stepped surface 13 of the housing 10 via the sleeve 40 and the filter core 20 to axially seal a gap between the first stepped surface 13 and the filter core 20 as shown in FIG. 4 .
The spacer 80 is mounted around the threaded rod 60 and is axially clamped between the nut 70 and the corresponding end of the sleeve 40 . In a preferred embodiment, outer diameters of the nut 70 and the spacer 80 are both slightly bigger than an outer diameter of the sleeve 40 , but the nut 70 and the spacer 80 do not block the channels 23 A, 23 B of the filter core 20 .
With reference to FIGS. 2 and 3 , when the air filter of the present invention is assembled, the threaded rod bracket 50 and the threaded rod 60 are mounted securely in the housing 10 first. Then, the filter core 20 , which has been assembled with the sleeve 40 and the resilient abutting element 30 , is mounted in the housing 10 from the inlet 11 , and is mounted around the threaded rod 60 at the same time. Since the outer diameter of the resilient abutting element 30 is smaller than the inner diameter of corresponding position of the housing 10 as shown in FIG. 4 , the filter core 20 can be put into the housing 10 easily and smoothly. Afterwards, the spacer 80 and the nut 70 are assembled on the sleeve 40 , and the nut 70 is rotated and tightened. Then the assembling of the air filter is completed. The air filter is easy to be assembled. In particular, the nut 70 not only allows easy application of the user's manual force for rotation, but also can be rotated by an electric tool, which enhances the efficiency of the assembling.
With reference to FIGS. 3 to 5 , the nut 70 abuts the sleeve 40 when rotated, and the sleeve 40 is moved with the filter core 20 and the resilient abutting element 30 , thereby making the resilient abutting element 30 axially and tightly abut the first stepped surface 13 . Thus, the gap between the filter core 20 and the first stepped surface 13 can be effectively sealed as shown in FIG. 4 , which ensures that the air entering the housing 10 from the inlet 11 will enter the filter core 20 . In addition, the outer diameter of the filter core 20 is bigger than the inner diameter of the inner periphery of the first stepped surface 13 , such that the filter core 20 may abut the resilient abutting element 30 tightly on the first stepped surface 13 .
With reference to FIGS. 3 and 5 , in addition, since the nut 70 only abuts the sleeve 40 , and the threaded rod bracket 50 does not need to abut the filter core 20 , the axial end surfaces of the filter core 20 are almost completely unblocked, thereby ensuring that air can smoothly pass through the filter core 20 .
With reference to FIG. 3 , moreover, since two ends of the threaded rod bracket 50 axially abut the second stepped surface 14 , the threaded rod bracket 50 may be supported in an axial direction, which further strengthens the supporting of the threaded rod 60 .
Nevertheless, when the filter core 20 is disassembled, since the filter core 20 protrudes out of the inlet 11 of the housing 10 , the user can directly hold the filter core 20 , which makes it easy for the user to apply force on and take out the filter core 20 .
With reference to FIG. 1 , the air filter of the present invention may be used in an air compressor or a diesel engine. When the air filter is in use, the air to be filtered directly enters the filter core 20 , which protrudes out of the inlet 11 of the housing 10 . With reference to FIGS. 6 and 7 , the air enters the channels 23 B, which are not sealed in the end surface of the filter core 20 that is adjacent to the inlet 11 . Then, when the air moves in the channels 23 B to the other end surface of the filter core 20 , the air is blocked by the end sealing adhesive layer 24 B. Consequently, the air passes through the wavy filtering sheet 22 to the other channels 23 A, and then flows out of the filter core 20 to arrive at the outlet 12 . When the air passes through the wavy filtering sheet 22 , the wavy filtering sheet 22 filters the suspended particles from the air to clean the air. In addition, the air may pass through the flat filtering sheet 21 B to arrive at another channel, and the flat filtering sheet 21 B also can filter the suspended particles from the air.
Since the adhesives 25 are spread on both surfaces of the wavy filtering sheet 22 , and are axially spread along the peaks of the wavy filtering sheet 22 , the adhered area between the wavy filtering sheet 22 and the flat filtering sheet 21 is large enough, and thus the connection between the filtering sheets 21 , 22 is strong enough. Therefore, no matter in use, wherein the air to be filtered enters the filter core 20 from the inlet 11 , or in a filter core 20 cleaning situation, wherein the clean air enters the filter core 20 from the outlet 12 , the wavy filtering sheet 22 and the flat filtering sheet 21 do not separate from each other, and do not axially protrude out along the direction of the air flow.
In addition, the adhesives 25 are axially spread along the peaks of the wavy filtering sheet 22 , thereby preventing spaces of the channels 23 A, 23 B from being occupied by the adhesives 25 to further avoid interfering with the air flow.
With reference to FIG. 3 , furthermore, with the resilient abutting element 30 axially abutting the periphery of the filter core 20 and the nut 70 axially abutting the sleeve 40 , which is adhered with the filter core 20 , both the resilient abutting element and the nut assist with preventing the wavy filtering sheet 22 and the flat filtering sheet 21 from separating from each other and axially protruding out.
In another embodiment, the filter core may be replaced by filter cores of other kinds, such as a filter core with adhesives spread not along the peaks but in other manners. In this situation, the embodiment also has the advantages of preventing the axial end surfaces of the filter core from being blocked.
In another embodiment, the outer diameter of the resilient abutting element may be equal to the inner diameter of the housing at a position corresponding to the resilient abutting element, thereby transversely supporting the resilient abutting element and the filter core firmly.
In another embodiment, the filter core may not protrude out of the inlet of the housing, and the housing further has a first housing and a second housing. The first and second housings are assembled together to form the accommodating space, and the filter core is mounted in the accommodating space.
In another embodiment, the housing may not have the second stepped surface, and the threaded rod bracket is transversely mounted securely on the inner wall of the housing.
In another embodiment, the threaded rod bracket may not be a bent elongated sheet but is of a different structure, as long as the threaded rod bracket can be mounted with and support the threaded rod.
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. | An air filter has a housing, a filter core, a resilient abutting element, a sleeve, a threaded rod bracket, a threaded rod and a nut. The axial sealing is achieved by axially compressing the resilient abutting element, such that the user does not have to apply much physical effort to compress the resilient abutting element. The user can easily push the filter core into the housing, and then rotates and tightens the nut, which can axially compress the resilient abutting element. It is easy to apply force on rotating the nut, and better still, the nut can be rotated by an electric tool, which further facilitates the convenience in assembling. Besides, the nut only abuts the sleeve, and the threaded rod bracket does not abut the filter core. Consequently, the filter core is not blocked, thereby making the air smoothly pass through the filter core. | 1 |
This application is a division of application Ser. No. 07/808,141 filed Dec. 16, 1991, now U.S. Pat. No. 5,206,335.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to selected poly(dianhydride) compounds made by the polymerization of certain aromatic dianhydrides. The present invention also relates to selected poly(dianhydride) compounds terminated with reactive end groups. The present invention further relates to selected poly(amic acid) compounds and selected poly(amic acid) compounds terminated with reactive end groups both of which are based on said selected poly(dianhydride) compounds. Still further, the present invention relates to selected poly(imide) compounds and selected poly(imide) compounds terminated with reactive end groups, both of which are based on selected poly(dianhydride) compounds.
2. Brief Description of the Prior Art
Dianhydrides are known precursors to many chemical products, including poly(amic acids) and poly(imide) resins. See, for example, C. E. Sroog, J. Polymer Science, Macromolecular Reviews, 11, 161 (1976). Known dianhydrides include 1,2,4,5-benzene tetracarboxylic dianhydride (CAS No. 89-32-7) also known as pyromellitic dianhydride (PMDA) which has formula (A): ##STR3##
Other known dianhydrides include those in the general formula (B): ##STR4## wherein R is an organic or inorganic linking group.
It is known to react dianhydrides with epoxides to form thermoset systems. It is also known to react dianhydrides with diamines to form poly(amic acids). For example, see the Sroog article cited above.
Also, it is known to convert poly(amic acids) into poly(imide) resins. See U.S. Pat. No. 4,480,088 which issued to Pike on Oct. 30, 1984.
It is also known to react poly(imides) with polymerizable end groups having amino functionalities to form poly(imides) terminated with reactive end groups. See, for example, U.S. Pat. No. 3,845,018 which issued to N. Bilow, A. L. Landis, and L. J. Miller on Oct. 29, 1974.
It is also known that poly(imides) and poly(imides) terminated with reactive end groups have utility as adhesives. See, for example, A. K. St. Clair and T. L. St. Clair "The Development of Aerospace Polyimide Adhesives" in Polyimides, K. L. Mittal, Ed. Vol. 2, Plenum Press, New York (1984).
It is also known to dimerize anhydrides to form bislactones are different in chemical structure from dianhydrides. See F. Ramirez, H. Yomanaka, and O. H. Basedow Journal of American Chemical Soc., 83, 173 (1961).
There is still a need for better high temperature epoxy systems which can be used as adhesives and composite matrices (e.g., composites used in aerospace applications). It is believed that the poly(dianhydrides) of the present may be suitable curatives for these epoxy systems.
There is also a need for better rigid-rod resin systems (i.e., where the resin structure has limited flexibility) to provide better strength to adhesives and composite matrices. It is believed that the poly(dianhydrides) with reactive end groups of the invention may solve this need for some applications.
There is also a need for resin systems which have a rigid rod portion and a flexible portion to provide both strength and flexibility to adhesives and composite matrices.
There is also a need for poly(imide)-type polymers which are more thermally stable and have more strength than the conventional ones made by dianhydrides and diamines. It is believed that the poly(imides) and poly(imides) with reactive end groups provide better thermal stability and better strength.
BRIEF SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to poly(dianhydride) compounds having formulae (I) or (II): ##STR5## wherein m is 0 to 50; and ##STR6## wherein n is from 0 to 20 and X═bond junction, oxygen atom, sulfur atom, SO 2 , C(CF 3 ) 2 , CO, C(CH 3 ) 2 , CF 2 --O--CF 2 , CH 2 , and CHOH.
The present invention is further directed to poly(dianhydride) compounds terminated with reactive end groups having formulae (III) and (IV): ##STR7## wherein m is defined as above and Z is selected from the group consisting of benzocyclobutene, a phenylacetylene, a cyclohexeneimide, a NADIC, N-propargylimide, ad a maleimide; and ##STR8## wherein X, Z, and n are the same as defined above.
The present invention is is further directed to poly(amic acid) compounds made from a poly(dianhydride) and a diamine and having either formulae (V) or (VI): ##STR9## wherein m is the same as defined above and Y is bond junction, oxygen atom, sulfur atom, CH 2 , C(CH 3 ) 2 , C(CF 3 ) 2 , CHOH, and O--C 6 H 4 --O; and wherein p is 1 to 100 and wherein T is defined as wither above-defined poly(dianhydride) or diamine used in this synthesis; and ##STR10## wherein n, T, X, and Y are the same as defined above and wherein q is 1 to 100.
The present invention is further directed to poly(amic acid) compounds terminated with reactive end groups made by reacting a poly(dianhydride) of formulae (I) and (II) with a polyamine to form a poly(amic acid) of formulae (V) and (VI) and then reacting said
The present invention is is further directed to poly(amic acid) compounds made form poly(dianhydride) and a diamine and having either formulae (V) or (VI): ##STR11## wherein m is the same as defined above and Y is bond junction, oxygen atom, sulfur atom, CH 2 , C(CH 3 ) 2 , C(CF 3 ) 2 , CHOH, and O--C 4 H 6 --O; and wherein p is 1 to 100 and wherein T is defined as either above-defined poly(dianhydride) or diamine used in this synthesis; and ##STR12## wherein n, T, X, and Y are the same as defined above and wherein q is 1 to 100.
The present invention is further directed to poly(amic acid) compounds terminated with reactive end groups made by reacting a poly(dianhydride) of formulae (I) and (II) with a polyamine to form a poly(amic acid) of formulae (V) and (VI) and then reacting said poly(amic acid) with polymerizable reactive groups and having formulae (VII) or (VIII): ##STR13## wherein m, p, Y, and Z are defined above; and ##STR14## wherein n, q, X, Y, and Z are the same as defined above.
The present invention is further directed to poly(imide) compounds made by dehydrating (either thermally or chemically) the above-noted poly(amic acid) compounds having formulae (V) and (VI).
These poly(imide) compounds are represented by formulae (IX) and (X): ##STR15## wherein m, p, T, and Y are the same as defined above. ##STR16## wherein n, q, T, X, and Y are the same as defined above.
The present invention is further directed to poly(imides) terminated with reactive end groups and made by heating said poly(amic acids) and having reactive end groups of formulae (XII) and XIII). These poly(imides) terminated with reactive end groups are represented by formulae (XI and XII): ##STR17## wherein m, p, Y, and Z are the same as defined above. ##STR18## wherein n, q, X, Y, and Z are the same as defined above.
DETAILED DESCRIPTION
The term "poly(dianhydride)" as used in the present invention refers to a compound containing two or more dianhydride moieties which are linked together or an isomeric form thereof [e.g., bis(biisocoumarins)].
The precursors to the poly(dianhydrides) of the present invention may be any dianhydride which is capable of being polymerized with a polymerizing agent. Preferred precursors include aromatic dianhydrides such as the following:
3,3'3,4'-benzophenone tetracarboxylic dianhydride [CAS No. 2421-28-5] (also referred to herein as BTDA)
3,3'4,4'-diphenylsulfone tetracarboxylic dianhydride [CAS No. 2540-99-0] (also referred to herein as DSDA)
4,4'-oxydiphthalic anhydride [CAS No. 1823-59-2] (also referred to herein as ODPA)
pyromellitic dianhydride (also referred to herein as PMDA)
The preferred class of polymerizing agents are phosphites. The preferred class of phosphites is trialkyl phosphites. The most preferred phosphite is triethyl phosphite. Other conventional polymerizing agents may be used instead.
The poly(dianhydrides) of the present invention are generally made by introducing the dianhydride precursor and excess polymerizing agent into a reaction vessel and heating the reaction mixture sufficiently to cause the desired polymerization.
If a phosphite polymerizing agent is used, it may also act as a solvent for this reaction. The preferred molar ratio of the dianhydride to phosphite polymerizing agent is from about 1:2 to about 1:100, more preferably from about 1:30 to about 1:60.
The polymerizing reaction is generally carried out at a temperature from about 100° C. to about 250° C., more preferably, from about 120° C. to about 180° C. The reaction is preferably carried out under atmospheric pressure, although super- and subatmospheric pressures may be used.
This polymerization reaction may occur in the presence of an additional solvent. Any polar, high boiling organic solvent capable of dissolving the dianhydride precursors may be employed. Xylene and dichlorobenzene are preferred solvents. However, it is most preferred to employ excess triethyl phosphite as a solvent.
Generally, it is preferred to carry out this polymerization reaction under an inert atmosphere. The preferred inert atmosphere is either a dry nitrogen or a dry argon atmosphere. The polymerization reaction may be carried out in standard chemical reacting vessels which allow heating and the use of an inert atmosphere blanket.
As recovery and purification steps for the poly(dianhydride), it is preferred to use any standard solid-from-liquid filtration apparatus followed by washing with methanol to remove solvent. The preferred filtration means is vacuum filtration.
Poly(dianhydrides) of formulae (I) and (II) which may be made according to this polymerization include the following:
Homopolymers of bis(4,4'-diphthalic anhydride) ethers
Homopolymers of bis(4,4'-diphthalic anhydride) sulfones
Homopolymers of bis(4,4'-diphthalic anhydride) ketones
Poly(biphthalyl) ethers
Poly(biphthalyl) sulfones
Poly(biphthalyl) ketones
Poly(4,4'-oxydiphthalic anhydride)
Poly(3,3'4,4'diphenylsulfone tetracarboxylic dianhydride)
The poly(dianhydrides) of the present invention may be used as curatives for epoxy resins.
The poly(dianhydrides) of the present invention may be reacted with a primary amine compound with a reactive group contained therein to produce the poly(dianhydride) terminated with reactive end groups (Z) of formulae (III) and (IV).
The primary amine compound sued as a precursor for compounds of formulae (III) and (IV) is denoted generically as H 2 N--Z, wherein Z is defined as above.
The preferred chemical classes of Z include the following six formulae: ##STR19##
The most preferred primary amine precursors are propargylamine (CAS No. 2540-71-7), aminophenyl acetylene (CAS No. 54060-30-9); and 4-aminobenzocyclobutene.
The poly(dianhydride) and the primary amino precursor are preferably reacted together in the presence of a solvent or mixture of solvents. The preferred solvents include either N,N'-dimethylacetamide, 1-methyl-2-pyrrolidinone, and N,N'-dimethyl formamide alone. The most preferred solvent system is N,N'-dimethylacetamide.
Generally, it is preferred to add sufficient solvent to dissolve the poly(dianhydride) reactant. The preferred amount of solvent is such that there is about 0.01 to about 0.05 moles poly(dianhydride) reactant per liter of solvent. In addition, molecular sieves are added to the reaction mixture to aid this dehydration reaction. Preferably, molecular sieves of about four angstroms are employed.
The reaction is generally carried out at a temperature of about 100° C. to about 200° C., preferably to about 110° C. to about 185° C. The reaction pressure is generally preferred to be atmospheric; although superatmospheric and subatmospheric pressures may be used.
Preferably, the mole ratio of the poly(dianhydride) precursor to the primary amine precursor is from about 1:2 to about 1:6, most preferably about 1:4.
The reaction is preferably carried out under an inert atmosphere such as dry nitrogen or dry argon. The most preferred atmosphere is a dry argon atmosphere. Any standard chemical reacting vessel which allows for heating and for the use of a dry inert atmosphere may be used herein.
Any standard recovery and purification steps for this product may be employed. The preferred recovery and purification steps for these poly(dianhydrides) terminated with reactive end groups involve the vacuum evaporation of the solvent away from the product followed by slowly introducing the mother liquor into water and then employing a standard solid-from-liquid filtration step, most preferably, vacuum filtration.
Several illustrative compounds of formulae (III) and (IV), above, include the following:
Propargyl terminated poly(ODPA)
Propargyl terminated poly(DSDA)
Propargyl terminated poly(BTDA)
Phenyl Acetylene terminated poly(ODPA)
Phenyl Acetylene terminated poly(DSDA)
Phenyl Acetylene terminated poly(BTDA)
The poly(dianhydrides) terminated with reactive end groups of formulae (III) and (IV) may be used in formulations for adhesives, dielectrics, and composite matrices.
The poly(dianhydrides) of formulae (I) and (II) may also be converted into novel poly(amic acids).
This reaction encompasses the reaction of the poly(dianhydrides) of formulae (I) and (II) with a polyamine, preferably an aromatic diamine.
The preferred diamines are aromatic diamines such as p-phenylenediamine, 2,2'-bis(4-aminophenyl) hexafluoropropane, 2,2'-bis(4-aminophenyl) methane, 2,2'-bis[4-(4 -aminophenoxy)phenyl]hexafluoropropane, 4,4'-oxydianiline, 4,4'-diamino diphenylsulfone (referred to herein as DADS), amine-terminated poly(dimethyl) siloxane, amine-terminated poly(diphenyl) siloxane, and 4,4'oxydianiline or 4-aminophenylether [CAS No. 101-80-4] (also referred to herein as ODA).
This reaction is generally carried out at room temperature and atmospheric pressure in the presence of a solvent.
Furthermore, the reaction is preferably carried out under an inert atmosphere such as dry nitrogen or dry argon. Any standard chemical reaction vessel may be used which allows for stirring and for the use of an inert atmosphere.
Preferably, the mole ratio of the poly(dianhydride) to the aromatic diamine is from about 1:1 to about 1:1.4. Most preferably, the mole ratio is from about 1:1.1 to about 1:1.3.
The preferred solvents for this reaction include N,N'-dimethylacetamide, N,N'-dimethylformamide, 1-methyl-2-pyrrolidinone, and ethyl lactate. The most preferred are 1-methyl-2-pyrrolidinone and ethyl lactate.
Any conventional recovery and purification steps may be used for these poly(amic acids).
Illustrative poly(amic acids) of formulae (V) and (VI) include the following:
Poly(amic acid) of poly(4,4'-oxydiphthalic anhydride and 4,4'-diamino diphenylsulfone;
Poly(amic acid) of poly(3,3'4,4'-diphenylsulfone tetracarboxylic dianhydride) and 2,2'-bis(4-aminophenyl) hexafluoropropane; and
Polyamic acid of poly(3,3',4,4'-benzophenone tetracarboxylic dianhydride) and 2,2'-bis(4-aminophenyl) hexafluoropropane.
The poly(amic acids) for formulae (V) and (VI) be used in formulations for adhesives, dielectrics, and composite matrices.
The poly(amic acids) of the present invention may be reacted with a primary amine compound to produce a poly(amic acid) terminated with a reactive end group of formulae (VII) or (VIII).
The primary amine compound used as a precursor for compounds of formulae (VII) and (VIII) is denoted generically as H 2 N--Z, wherein Z is defined as above.
The preferred reactive amino end group precursors are propargylamine (CAS No. 2540-71-7), 4-aminophenyl acetylene (CAS No. 54060-30-9); and 4-aminobenzocyclobutene.
The poly(amic acid) and primary amine precursor are preferably reacted together in the presence of a solvent or mixture of solvents. The preferred solvents include either N,N'-dimethylacetamide, 1-methyl-2-pyrrolidinone, and N,N'-dimethyl formamide alone.
Generally, it is preferred to add sufficient solvent to dissolve the poly(amic acid) reactant. The preferred amount of solvent is such that there is about 0.01 to about 0.05 moles poly(amic acid) reactant per liter of solvent.
The reaction is generally carried out at a temperature from about 100° C. to about 200° C., preferably to about 110° C. to about 185° C. The reaction pressure is generally preferred to be atmospheric; although superatmospheric and subatmospheric pressures may be used. Preferably, the mole ratio of the poly(amic acid) precursor to the primary amine compound is from about 1:2 to about 1:6, most preferably about 1:4.
The reaction is preferably carried out under an inert atmosphere such as dry nitrogen or dry argon. The most preferred atmosphere is a dry argon atmosphere. Any standard chemical reacting vessel which allows for heating and for the use of a dry inert atmosphere may be used herein.
Any standard recovery and purification steps for this product may be employed. The preferred recovery and purification steps for these poly(amic acids) terminated with reactive amino end groups involve the vacuum evaporation of the solvent away from the product followed by slowly introducing the mother liquor into water and then employing a standard solid from liquid filtration step, most preferably, vacuum filtration.
Several illustrative compounds of formulae (VII) and (VIII), above, include the following:
Phenylacetylene Terminated [(Poly ODPA)·ODA]
Phenylacetylene Terminated [(Poly BTDA)·ODA]
Phenylacetylene Terminated [(Poly DSDA)·ODA]
Propargyl Terminated [(Poly ODPA)·DADS]
Propargyl Terminated [(Poly BTPA)·DADS]
Propargyl Terminated [(Poly DSDA)·DADS]
The poly(amic acids) having terminated with reactive end groups of formulae (VII) and (VIII) may be used in formulations for adhesives, dielectrics, and composite matrices.
The above-noted poly(amic acids) of formulae (V) and (VI) may be converted into novel poly(imide) compounds of formulae (IX) and (X) by subjecting them to either chemical imidization or elevated temperatures in the presence of a solvent. Preferably, this reaction is carried out at atmospheric pressure under an inert gas atmosphere (e.g., dry nitrogen or dry argon). Any standard film casting apparatus which allows for thermal curing of the precursor poly(amic acids) and for removal of the carrier solvents may be used.
A preferred cure schedule for making these poly(imides) is to cure the poly(amic acids) for one hour at 150° C. followed by curing for two hours at 250° C.
Preferred carrier solvents for this reaction include N,N'-dimethylacetamide, N,N'-dimethylformamide, 1-methyl-2-pyrrolidinone, and ethyl lactate. The most preferred solvents are 1-methyl-2-pyrrolidinone and ethyl lactate.
Illustrative poly(imides) of formulae (IX) and (X) include the following:
Poly[hexafluoropropyl diphenyl poly(3,3'4,4'-diphenylsulfone dianhydride)]
Poly[hexafluoropropyl diphenyl poly(3,3'4,4'-benzophenone dianhydride)]
Poly[oxydiphenyl poly(3,3'4,4'-benzophenone dianhydride)]
Polyimide of poly(3,3',4,4'-benzophenone tetracarboxylic dianhydride) and 2,2'-bis(4-aminophenyl) hexafluoropropane
Polyimide of poly(3,3',4'4-diphenylsulfone tetracarboxylic dianhydride) and 2,2'-bis(4-aminophenyl) hexafluoropropane
Polyimide of poly(3,3',4'4-benzophenone tetracarboxylic dianhydride) and 4,4'-oxydianiline
The poly(imides) for formulae (IX) and (X) may be ingredients in adhesives, dielectrics, and composite matrice compositions.
The above-noted poly(amic acids) having reactive end groups of formulae (VII) and (VIII) may be converted into novel poly(imide) compounds having reactive end groups of formulae (XI) and (XII).
Illustrative poly(imides) of formula (XI) and (XII) include the following:
Phenyl Acetylene Terminated [Poly(PMDA)·ODA]Polyimide
Phenyl Acetylene Terminated [Poly(ODPA)·ODA]Polyimide
Phenyl Acetylene Terminated [Poly(BTDA)·ODA]Polyimide
Propargyl Terminated [Poly(PMDA)·DADS]Polyimide
Propargyl Terminated [Poly(OSDA)·DADS]Polyimide
Propargyl Terminated [Poly(ODPA).DADS]Polyimide
These poly(imide) compounds having reactive end groups of formulae (XI) and (XII) may be ingredients in adhesives, dielectrics, and composite matrix compositions.
The following Examples are provided to further illustrate the present invention. All parts and percentages are by weight and all temperatures are by degrees Celsius, unless explicitly stated otherwise.
EXAMPLE 1
SYNTHESIS OF POLY(OXYDIPHTHALIC ANHYDRIDE)
A 1,000 ml 3-necked round bottom flask fitted with an overhead mechanical stirrer and a condenser was charged with triethyl phosphite (581 grams, 3.50 moles). This compound was then deoxygenated with dry argon for 20 mins. To this solution was added 4,4'oxydiphthalic anhydride (ODPA) (31.0 grams, 0.10 moles); the solution was then heated to reflux under argon (approximately 135° C.) for 24 hours. An orange precipitate formed on the sides of the flask and on the stirring rod. The mixture was cooled to 0° C. and the material was collected via vacuum filtration, washed with 500 ml of cold methanol, and dried overnight at 80° C. to yield 22.96 g or product. Characteristic IR peaks: 1,776, 1,018 cm -1 . Gel permeation chromatography showed M n =1,870, M w =2,445.
EXAMPLE 2
SYNTHESIS OF POLY(3,3,'4,4'-BENZOPHENONE TETRACARBOXYLIC DIANHYDRIDE)
The same reaction as above was carried out, except (3,3',4,4'-benzophenone tetracarboxylic dianhydride) (32.2 grams, 0.10 moles) was substituted for ODPA. These reactants were refluxed for 12 hours. Again, an orange material precipitated, was vacuum filtered, and washed with methanol to yield 30.80 grams of an orange-yellow solid. Characteristic IR peaks: 1,785, 1,017 cm -1 . Gel permeation chromatography showed M n =3,569, M w =10,682.
EXAMPLE 3
REACTIVE END CAPPING OF POLY(4,4'-OXYDIPHTHALIC ANHYDRIDE)
A 500 ml glass round bottom flask was fitted with a condenser and overhead mechanical stirrer. This flask was charged with dimethyl acetamide (40 ml) and poly(4,4'-oxydiphthalic anhydride) (13.7 grams, M w =2,445). This mixture was warmed to 50° C. and stirred until all materials were dissolved. At this time, m-aminophenyl acetylene (2.4 grams, 0.0205 moles) was added and the reaction temperature was raised to 135° C. This was followed by the addition of molecular sieves, 4A. Then the mixture was held at 165° C. for 24 hours. The molecular sieves were then removed by filtration through a Celite Pad.
After cooling the reaction mixture, the remaining materials were dropped very slowly into quickly stirred water to precipitate solids. The materials were collected via vacuum filtration on a fritted glass filter. The product was dried overnight in a 100° C. oven. The material remaining was a brown powder (15.11 grams) with a melting range of 135°-150° C., (IR peaks, cm -1 -3,446, 2,160, 1,777, 1,718, 790).
EXAMPLE 4
REACTIVE END CAPPING OF POLY(3,3',4'-BENZOPHENONE TETRACARBOXYLIC DIANHYDRIDE)
The same reaction, as above, was carried out, except poly(3,3',4,4'-benzophenone tetracarboxylic dianhydride)(10 grams, M w =4,224) was substituted for poly(4,4'-oxydiphthalic anhydride). An orange-brown powder (9.01 grams) with a melting range of 165°-177° C. was recovered (IR, cm -1 3,285, 1,768, 1,720, 1,660, 741, 683).
EXAMPLE 5
SYNTHESIS OF POLY(AMIC ACIDS) FROM POLY(DIANHYDRIDES)
In a 500 ml round bottom flask, 1-methyl 2-pyrrolidinone (250 ml) was sparged with dry argon for 20 minutes. After sparging, poly(BPDA) (25 g. M w =1,080) prepared by the above method was introduced and dissolved with magnetic stirring. At this point, oxydianiline (4.63 grams, 0.023 moles) was introduced and the solution was stirred for 24 hours at room temperature under dry argon.
EXAMPLE 6
SYNTHESIS OF POLY(IMIDES) FROM POLY(AMIC ACID) SOLUTIONS
To convert poly(amic acids) produced above to poly(imide) systems, the mixture can be cast into film form on a suitable substrate (for example, Teflon coated foil). At this point, the solution can be cured either in atmospheric pressure argon or in a vacuum to remove the solvent. Temperatures for this cure can range from 100° to 250° depending upon pressure. After 2-5 hours of cure, the resulting polyimide can be recovered from the surface of the foil.
EXAMPLE 7
SYNTHESIS OF POLY(AMIC ACIDS) TERMINATED WITH REACTIVE END GROUPS
Termination of poly(amic acids) with reactive end groups was accomplished using the amic acid preparation from above with a slight modification in ratios of poly(dianhydride) to aromatic diamine, such as oxydianiline. Instead of the 1:1 molar ratio, the concentration of the aromatic diamine should be added so the ratio is 0.9:1 aromatic diamine:poly(dianhydride), for example oxydianiline (4.17 grams, 0.021 moles):poly (BPDA) (25 grams M w =1,080) in 250 ml of 1-methyl 2-pyrrolidinone sparged with argon. These reactants were stirred for 24 hours at room temperature as above. At the end of 24 hours, a reactive end group, such as aminophenyl acetylene (2.4 grams, 020 moles) was added and stirred at room temperature for 8 hours. At this point, the amic acid terminated with reactive end groups is synthesized. There are various means for adjusting the lengths of the poly(amic acid) segments.
EXAMPLE 8
SYNTHESIS OF POLY(IMIDE) TERMINATED WITH REACTIVE END GROUPS
Poly(imides) with reactive end groups are synthesized from the poly(amic acids) with reactive end groups made in the previous sample. These amic acids in 250 ml of 1-methyl 2-pyrrolidinone are heated for 24 hours at 165° C. to convert amic acids to imides. At this point, the poly(imides) can then be precipitated by pouring the mixture into stirring methanol. After precipitation, the poly(imide) can be collected on a fritted glass funnel and dried in a vacuum oven.
While the invention has been described above with reference to specific embodiments thereof, it is apparent that many changes, modifications, and variations can be made without departing from the inventive concept disclosed herein. Accordingly, it is intended to embrace all such changes, modifications, and variations that fall within the spirit and broad scope of the appended claims. All patent applications, patents, and other publications cited herein are incorporated by reference in their entirety. | Poly(dianhydride) compounds having formulae (I) and (II): ##STR1## where m is 0 to 50. ##STR2## wherein n is 0 to 20 and X is bond junction, oxygen atom, sulfur atom, SO 2 , C(CF 3 ), CO, C(CH 3 ) 2 , CF 2 --O--CF 2 , CH 2 , and CHOH. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in general to control systems for a paper refiners and in particular to a novel programmable refiner controller.
2. Description of the Prior Art
U.S. patents such as U.S. Pat. No. 3,604,646 which issued on Sept. 14, 1971 assigned to the assignee of the present application and in which the inventors are Marion A. Keyes IV and John A. Gudaz and U.S. Pat. No. 3,654,075 which issued on Apr. 4, 1972 in which the inventors are Marion A. Keyes IV and John A. Gudaz assigned to the assignee of the present application disclose control systems for paper refiners and the disclosure in these patents is hereby incorporated by reference.
SUMMARY OF THE INVENTION
The present invention comprises a programmable refiner controller which utilizes a microprocessor, whereby it is desired to combine two mass flow inputs which together represent the total mass flow and to relate the total mass flow to a power set point resulting in uniform and equal changes in power with actual changes in mass of dry pulp. In the present invention this problem is solved by treating the flow input as a percentage value BCD since the flow meters range from zero to a maximum and the consistency input is converted to a factor because consistency transmitters have a range from a minimum value consistency to a maximum value. The factor is equal to 1 at 50% consistency transmitter output and is equal to the maximum consistency over the mean consistency at 100% consistency transmitter output. This produces a resulting set point representative of a percent of maximum tons per day of dry pulp and is used to control the power in kilowatts which is directly proportional to horse power applied to the drive motor of the refiner.
In the present invention, a microprocessor which has a programmable read only memory is utilized and the memory routine controls the microprocessor so that for each input it operates so as to properly control the power applied to the system.
Thus, the invention comprises an automatic controller which can also be adapted for operation with consistency transmitters of different ranges so as to provide accurate control.
Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the programmable refiner controller of the invention;
FIG. 2 is a block diagram in greater detail of a portion of the apparatus; and
FIG. 3 is a table giving constant values for different transmitter.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a motor 37 which drives through its output shaft 41 and a clutch, a refiner 39 which might be, for example a paper refiner such as described in U.S. Pat. No. 3,654,075. The refiner has a suitable beater element. The fluid stock enters the refiner 39 through an inlet conduit 11 and is discharged through an outlet conduit 17 and the heavy fiber stock which has been refined that moves through the conduit 17 is forwarded to the paper making machine where it is made into paper. The refiner 39 includes rotary and stationary disk elements which based upon the position between them as determined by a positioning mechanism 42 that moves these elements relative to each other determines the amount of refining work applied to the stock.
The consistency transmitter 13 receives an input 12 from conduit 11 and produces an output signal A indicative of the consistency of the stock in the conduit 11. A flow transmitter 19 receives an input 18 from the conduit 17 and produces an output signal on line 21 indicative of the flow through the conduit 17 of the stock.
The outputs of the flow transmitter 19 and the consistency transmitter 13 are supplied to a programmable refiner controller designated generally as 10 which includes the signal converter 14. The signal converter 14 changes the input analog signal A to a signal B which represents the percentage full scale of the transmitter 13. For example, if the transmitter range is 4--20 milliamperes and the measured signal is 12 milliamperes the output of the converter 14 will be 50. If the measured signal changes to 20 milliamperes, the output will change to 100. Thus, the output signal B is indicative of the percentage full scale of the transmitter 13. The signal converter 22 performs a similar function on the flow measurement signal D appearing on lead 21 and converts it into a percentage flow signal E that is supplied to lead 23. After the signal has been converted to a percentage signal, the consistency signal B is transformed to a mass factor by multiplying the signal B by an adjustable constant P1 in the multiplier 16 to obtain a signal C. The signal C is supplied to an adder 24 which receives another adjustable constant P2 from the constant generator 27 and the output of the adder 24 comprises a signal G. The signal G is multiplied in multiplier 26 with the representative percentage flow signal E which produces an output signal H which represents the tons per day flow through the refiner 39.
The resultant tons per day signal H is multiplied in the multiplier 70 with a signal obtained from a set point potentiometer 60 which is controlled by a knob 28 which sets the net kilowatts per day per ton. This set point is scaled in HPD/T net as shown in the following scaling sheet.
______________________________________Ratio Set PointPotentiometer Signal Net Horsepower-Output 29 Days Per Ton______________________________________.00 .00.05 .18.10 .36.15 .54.20 .71.25 .89.30 1.07.35 1.25.40 1.48.45 1.61.50 1.79.55 1.97.60 2.14.65 2.32.70 2.68.80 2.86.85 3.04.90 3.22.95 3.401.00 3.571.09 3.751.10 3.931.15 4.111.20 4.291.25 4.471.30 4.65The motor connected gross horsepower has been exceeded.1.40 5.001.45 5.181.50 5.36______________________________________
Specifically, the Ratio Set Point Potentiometer produces a signal multiplier ranging from 0.0 to 3.0 and will then be scaled according to the maximum Net Horsepower of the motor 37 divided by the maximum flow from flow transmitter 19 and the maximum stock consistency as can be measured by the consistency transmitter 13. These maximum values produce a maximum net horsepower per bone dry ton of paper pulp which is attainable, due to the limits of the installed system hardware, and is in turn scaled linearly with respect to the Ratio Set Point Potentiometer scale. Therefore, the Ratio Set Point Potentiometer 60 controls the gain of the signal H to arrive at a value of net KW per day per ton.
An adder 31 adds to the signal I the no-load KW signal which can be obtained from a variable potentiometer 61 that can be set to provide a signal representative of the percent no-load kilowatts of the total system gross kilowatts. The output of the adder 31 now comprises a signal M indicative of the gross kilowatts. The signal M is in percent and is received by signal converter 32 which changes this percent gross kilowatt signal M to an analog signal M' for comparison with the actual power measurement signal N. Signal N is received from a power transmitter 36 coupled to the motor 37 by shaft 38. Comparator 33 produces an output N' which is the difference between the signals N and M'. The power controller 34 senses the difference signal N' and provides a corrective signal P which is supplied to the refiner adjusting mechanism 42.
It is essential that in combining the two flow and consistency signals, that a mass factor be derived from the consistency signal, because in obtaining a mass flow signal we are combining flow which is measured from zero to maximum and consistency which is measured from a given minimum consistency to a maximum consistency. The consistency signal, because of its narrow span and non-zero minimum range, affects the total mass flow to a much lesser degree than the flow signal. The consistency signal is not generated linearly in measurement units and therefore must be compensated for by using the mass factor method described. A specific example is given.
ASSUME
(A) Flow at Time X=500 GPM
(B) Flowmeter calibration=0-1000 GMP, 4-20 MA output
(C) Consistency at Time X=3.75
(D) Consistency Transmitter Cal.=3.0-4.5, 4-20 MA output
(E) T/D at Time X=500 GMP×3.75×0.06=112.5 T/D
(F) Available HP=600 HP
(G) No-Load HP=60 HP
(H) Desired HPD/T (net)=3.57
USING PRC METHOD
1. Consistency Transmitter output at Time X=12 MA=50%
2. Flowmeter output at Time X=12 MA=50%
3. From FIG. 3 P 1 =0.004
P 2 =0.8
REFERRING TO FIG. 1
Signal (A)=12 MA
Signal (B)=50
Signal (C)=(B)×P 1 =50×0.004=0.2
Signal (F)=P 2 =0.8
Signal (G)=(F)+(C)=0.8+0.2=1.0
Signal (D)=12 MA
Signal (E)=50
Signal (H)=(E)×(G)=50×1.0=50
______________________________________Signal (K) = Refer to listing of Net HPD/T vs. Ratio From that table at a desired net HPD/T, we need a ratio = 1.0 Therefore Signal K = 1.0______________________________________
Signal (I)=(K)×(H)=1.0×50=50 ##EQU1## Signal (M)=(I)+(L)=50+7.46=57.46% ##EQU2##
FIG. 2 illustrates the PRC 10 and the inputs D, A and N. Power leads 51, 52 and 53 supply three phase power to the motor 37 and the transmitter 36 and lead 62 comprises output from the refiner of alarm signals that are supplied to the PRC 10. The gear motor starter relay 63 is also connected to the controller 10.
The PRC has been designed to solve all of the complex problems of meeting all the signal and measurement units conversion factors. Ultimately, it will be necessary to interface the PRC with systems other than the standard 1.5% consistency range transmitter. This can be done by simply solving for new constants based on the existing formulas and hardware. ##EQU3## The constants have the following ranges in P.R.C. prototype:
P 1 =0.0001 to 0.0099 step 0.0001
P 2 =0.01 to 0.99 step 0.01
The span and range of consistency transmitter affects P 2 . Constant P 2 is solved for first and substituted into the equation for P 1 , P 2 will never be out of range unless the consistency transmitter range has 0.0% consistency as a minimum. P 2 will cause P 1 to fall out of range if the following exists.
P 1 is out of range if 0.50>P 2 >0.99
Effectively causing P 1 to be >0.0099 or <0.0001.
Specifically P 2 will cause P 1 to be out of range if the following relationship exists.
X=minimum consistency ##EQU4##
Therefore, as the minimum consistency of the consistency transmitter increases, the usable span can also increase and alternately as the minimum consistency of the transmitter decreases, the usable span must decrease if constants P 2 and P 1 are at the limits of their range as defined by the ranges given above.
Referring to the drawings, a signal (A) is derived from a measurement of consistency and is transmitted to a signal converter within the PRC module. The signal converter changes this analog signal (A) to a signal (B) representative of percent full scale of the transmitter.
For example: If the transmitter range is 4-20 MA and the measured signal is 12 MA, the output of the converter will be 50. If the measured signal changes to 20 MA, the output will change to 100.
The same function is performed on the flow measurement signal (D) resulting in a percent flow signal (E).
After the conversion to percent, the consistency signal (B) is transformed to a mass factor by multiplying an adjustable constant P 1 and adding to the result (C) another adjustable constant P 2 . The adjustable constants P 1 and P 2 are derived from the consistency range of the particular transmitter used.
For example: Assume the range of the consistency transmitter is 3.0 to 4.5-- ##EQU5##
These constants are derived for each transmitter range encountered. FIG. 3 comprises a summary table of values of P 1 and P 2 vs. transmitter range.
Although the invention has been described with respect to preferred embodiments, it is not to be so limited as changes and modifications can be made which are within the full intended scope of the invention as defined by the appended claims. | A micro-processor is useable which can be programmed so as to provide a controller for a refiner, for example, for a paper stock refiner in which flow and consistency transducers are utilized to measure these parameters of the paper stock and these signals are supplied to a programmable refinery controller which also receives an input of the power supplied to the refinery and supplies a control signal to the refiner so as to control the power supplied to the refinery. One or more fixed inputs may also be supplied to the controller. | 3 |
BACKGROUND OF INVENTION
The invention concerns a device for generating a dry, cold air flow for treatment of rheumatic diseases.
Cold therapy for treatment of rheumatic diseases was developed some years ago in Japan and is increasingly gaining recognition. Both whole body therapy and local therapy has been applied. In whole body therapy, the patient must remain in a severly chilled room for a specific period of time. In local therapy, a cold air flow is directed onto the diseased body portion. The invention concerns a device for local therapy.
The cold air flow for local therapy must be dry and free of ice. Since the air is cooled to approximately -150° C., it is by nature dry, but the ice particles removed from the air by freezing must be prevented from impacting on the body surface. This would cause cold damages at least in the form of micronecroses.
From the Japanese disclosure document for design registration, No. 30 189/80 (Application No. 114 029/78), a device is known for generating a dry, cold air flow for treatment of rheumatic diseases, which fulfills the above-mentioned requirements. In this device, the air flow generated by means of a blower is led through an air cooler, in which it is cooled to the required low temperature. This air cooler is a heat exchanger with cooling hoses, in which liquid nitrogen is being evaporated. The moisture is frozen out at these cooling hoses. The dry cold air is removed from the air cooler through an insulated hose and fed to the treatment location.
Although this device fulfills its purpose in a satisfactory manner, it has some disadvantages, particularly in respect to economy. Thus, the investment costs are relatively high, since the heat exchanger for the air cooling is expensive. The heat exchanger must be set up outside of the treatment rooms. For this reason, long feed lines are required. The long hose line for the cold air is also expensive, due to the cost of the insulation. When the device is started up, it is necessary to first cool the heat exchanger with its great mass as well as the hose lines, before it is possible to give the patient the cold treatment. The start-up times are thus considerable. The loss of cooling agent per treatment is correspondingly great. If the device is being used for a longer period of time without interruption, which is frequently the case in the practice, the moisture frozen out of the air may ice the surfaces of the heat exchanger and cause a failure of the device. This can be prevented only if the operation of the equipment is set for regular intervals to thaw off the accumulated moisture.
SUMMARY OF THE INVENTION
The purpose of the invention is to create a device for generating a dry, cold air flow for treatment of rheumatic diseases, which does not have these disadvantages but is particularly ready for rapid use with low cooling agent consumption and suitable for constant use.
A device was designed for generating a dry, cold air flow for treatment of rheumatic diseases, with a connection to a feed line for a cryogenic liquefied gas, a blower for generating the air flow, and a device for heat exchange between liquefied gas and air flow, which makes possible a separation of the frozen out moisture, whereby, according to the invention, a cyclone separator serves as heat exchanger, the intake line of which is connected over a line with the outlet opening of the blower, in which the connection for feeding the liquefied gas ends, and at the outlet opening of which a flexible hose is attached.
Accordingly, the principle of the invention is to design a device where there is a direct heat exchange between the cryogenic liquefied gas, generally nitrogen, and the air. For this purpose, the liquefied gas is sprayed into the intake line of a cyclone separator. The air is thereby immediately and greatly cooled, and the moisture contained therein freezes out in the form of ice particles.
The heat exchange is continued in the cyclone separator, and the ice is separated. The separated moisture collects in the lower part of the cyclone separator, thaws out there and is discharged from time to time in the form of water, e.g., during interruptions in the operation of the device.
When liquid nitrogen is used as a cooling agent, physician and patient may be endangered due to excessive nitrogen content in the breathing air. In order to eliminate this danger, a ventilator for discharging air is installed in the vicinity of the device according to the invention which is automatically activated when the device is started up. In addition, an electrical blockage may serve the purpose of interrupting the feed of liquid nitrogen if the air discharge fan does not operate. However, such safety devices would be superfluous if liquid air is used as a cooling agent.
THE DRAWINGS
FIG. 1 is a perspective view of a device with separate, removable supply container for liquid nitrogen; and
FIG. 2 is a schematic representation of the device according to FIG. 1 combined with an air discharge fan.
DETAILED DESCRIPTION
The equipment for generating the cold air flow is contained in the interior of the device represented in FIG. 1; start-up and monitoring are achieved by means of instrumentation and switches on the front side 1 of the device. A flexible insulated hose 2 leads out of the device and ends in a hand-held piece 3. Further, the device has a connection opening 4 for liquid nitrogen feed and a plug 5 for establishing an electrical connection. Furthermore, the device has a separate, removable supply container 6 for liquid nitrogen. In the interior of this supply container 6 is the actual nitrogen container 7. It also has a connection 8, over which liquid nitrogen can flow out of the liquid nitrogen container 7. In addition, there is a plug 9 for electrical connection. The device is ready for operation as soon as the supply container 6 is connected, whereby the plugs 5 and 9 as well as the connection opening 4 and the connection 8 are engaged.
FIG. 2 is a schematic representation of the device in FIG. 1. Liquid nitrogen is drawn from the nitrogen container 7 by means of the pump 10. The rapid coupling 11 represents the connection between the connection point 8 and the connecting opening 4. In the connection 8, which is lengthened by means of the rapid coupling 11, there is also a magnet valve 12 and an adjustable diaphragm 13. The air flow is generated by a blower 14, which suctions in air through the filter 15. The outlet opening of the blower 14 is connected to intake opening of a cyclone separator 17. According to the invention, the connection 8 from the nitrogen container 7 ends in the line 16. The insulated hose 2 with the hand-held piece 3 is attached to the outlet connectors 18 of the cyclone separator 17. At the lower, conical part of the cyclone separator 17, there is a valve 19, to which is connected a discharge water separator and evaporator 20. In the vicinity of the hand-held piece 3, there is a temperature measurement device 21. In the vicinity of the device, there is also an air discharge fan 22. By means of an electrical connection, which is not shown, it is also achieved that the nitrogen feed is interrupted by the magnet valve 12 if the air discharge fan 22 does not function, e.g., due to a technical defect. Also in the vicinity of the device according to the invention, there is a warning device 23 for the oxygen level; however, this does not have a functional connection with the device according to the invention.
When the device is started up, the air discharge fan 22, the blower 14 and the pump 10 are simultaneously activated. Thereby, liquid nitrogen is sprayed into the line 16 through the connection 8. There is then a direct heat exchange between the nitrogen sprayed into the line 16 and the air from the blower 14. Since both the line 16 and the cyclone separator 17 have little mass, the entire device is rapidly cooled, so that only little nitrogen is required for cooling the device according to the invention to its operating temperature. The moisture contained in the air from the blower 14 freezes out in the form of ice particles, which are separated in a known manner by means of the cyclone separator 17. They collect in the lower, conical part of the cyclone separator 17, where they thaw out again and are discharged from time to time through the valve 19 into the discharge water separator and evaporator 20. The dry, cold air with some admixture of nitrogen leaves the cyclone separator 17 through outlet connectors 18, insulated flexible hole 2, and hand-held piece 3. It then arrives directly onto the body portion to be subjected to the treatment. The temperature of the air flow is monitored and adjusted by means of the temperature measurement device 21. The temperature adjustment is extremely simple, since only the quantity of sprayed-in nitrogen need be varied. The air quantity can also be easily varied by means of changing the speed of the blower 14. The air mixed with nitrogen is constantly being suctioned out by means of the air discharge fan 22. Should the oxygen level nevertheless fall below a permissible value, this will be optically and acoustically indicated by means of the oxygen warning device 23.
The device according to the invention is a compact unit, which can be set up in any room without external feed lines. The supply container 6 can easily be exchanged at any time when the nitrogen in the container 7 is running out. Since the liquid nitrogen can be stored in small quantities directly in the treatment room, it is possible to utilize the very shortest connections. The only requirement is a connection to the electrical power supply. The quantities of air and liquid nitrogen which are to be mixed with one another may be adjusted separately and independently of one another. The temperature of the cold air flow can be preselected and adjusted according to desire or requirement. The device is ready for operation within very short time. The ice separation in the cyclone separator 17 is safe and reliably prevents ice particles to touch the body surface of the patient which could cause cold injuries due to micronecroses. | A device for generating a dry, cold air flow in the treatment of rheumatic diseases includes a cyclone separator as its heat exchange device. The intake line of the cyclone separator is connected to the outlet line of the blower means of a line in which the cryogenic liquefied gas feed ends. The outlet opening of the cyclone generator has attached to it an insulated flexible hose. | 0 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to processes for producing 3,3,3-trifluoro-2-hydroxypropionic acid and its derivatives, which are useful intermediates for medicines and liquid crystals.
[0002] There are known the following first to fourth processes for producing 3,3,3-trifluoro-2-hydroxypropionic acid, which is represented by the formula 2.
[0003] In the first process, it is derived from 3,3,3-trifluoro-2-hydroxypropanol or 3,3,3-trifluoropropene-1,2-oxide (see Synlett, 7, pp. 507-508 (1994); and Japanese Patent Application Publications 5-078277 and 5-078278).
[0004] In the second process, it is derived from trifluoropyruvate (see Chem. Ber., 125(12), pp. 2795-2802 (1992)).
[0005] In the third process, it is derived from trifluoroacetaldehyde (see Japanese Patent Application Publication 3-148249).
[0006] In the fourth process, it is derived from hexafluoroisopropanol (see Nippon Kagaku Kaishi No. 9, pp. 1576-1586 (1989)).
[0007] Other processes for producing 3,3,3-trifluoro-2-hydroxypropionic acid are disclosed in Japanese Patent Application Publications 2002-080429 and 2001-226316; Organic Letters, 3(3), pp. 457- 4 59 (2001); Tetrahedron Letters, 41(23), pp. 4603-4607 (2000), and Tetrahedron Letters, 41(22), pp. 4507-4512 (2000).
[0008] Although it is possible to obtain 3,3,3-trifluoro-2-hydroxypropionic acid with a relatively high yield by the above conventional processes, the raw materials (i.e., trifluoromethyl-containing compounds) used in these processes have very high prices. Therefore, these processes are not suitable for industrially producing 3,3,3-trifluoro-2-hydroxypropionic acid.
[0009] The following reaction scheme is taught in WO 02/00601 corresponding to European Patent Application EP 1300391 A1; WO 00/55113 corresponding to U.S. patent application Publication 2002/0026081 A1; Huaxue Gongcheng (Xilan, China), 28(4), pp. 44-45, 51 (2000); Japanese Patent Application Publication 10-139724; WO 98/07687 corresponding to U.S. Pat. No. 6,020518; J. Indian Chem. Soc., 66(4), pp. 239-240 (1989); J. Antibiot., 40(11), pp. 1555-1562 (1987); Tetrahedron, 37(17), pp. 3061-3065 (1981); Yukagaku, 28(7), pp. 501-502 (1979); and German Patent Application Publication 2648300 corresponding to U.S. Pat. No. 4,052,460.
[0010] Furthermore, it is disclosed in Chem. Ber., 125(12), pp. 2795-2802 (1992) that 3,3,3-trifluoro-2-hydroxypropionic acid alkyl ester is protected at its hydroxyl group (bonded to the second carbon) with a THP (tetrahydropyranyl) group, and then its alkoxycarbonyl group (—COOR) is reduced to a hydroxymethyl group (—CH 2 OH) using lithium aluminum hydride. Then, it is necessary to conduct a deprotection to produce 3,3,3-trifluoro-2-hydroxypropanol. Thus, the process of this publication is cumbersome for industrial production.
[0011] Japanese Patent Application Publication 2000-063306 discloses that 1,1-dichloro-3,3,3-trifluoroacetone is hydrolyzed in the presence of disodium hydrogenphosphate to trifluoropropanetetraol. It is further disclosed in this publication that the hydrolysis is conducted at a pH of from 2 to 9.
[0012] Japanese Patent Application Publication 5-70406 discloses a process for producing a β, β,β-trifluorolactic acid ester by reacting β,β,β-trifluorolactic acid with an alcohol (having a carbon atom number of at least 3) in the presence of a catalyst.
SUMMARY OF THE INVENTION
[0013] It is an object of the present invention to provide a process for efficiently producing 3,3,3-trifluoro-2-hydroxypropionic acid or its derivative(s), which are useful intermediates for medicines and liquid crystals.
[0014] According to the present invention, there is provided a process for producing 3,3,3-trifluoro-2-hydroxypropionic acid represented by the formula 2. This process includes the step of (a) bringing a 1,1-dihalogeno-3,3,3-trifluoroacetone represented by the formula 1 into contact with a basic aqueous solution (for example, having a pH of 12 or higher),
[0015] wherein X is Cl, Br or I.
[0016] The above raw material, 1,1-dihalogeno-3,3,3-trifluoroacetone, is industrially available with a low price.
[0017] It is possible to convert 3,3,3-trifluoro-2-hydroxypropionic acid into 3,3,3-trifluoro-2-hydroxypropanol represented by the formula 4 almost quantitatively, by a process including the steps of:
[0018] (b) reacting the 3,3,3-trifluoro-2-hydroxypropionic acid, which has been obtained by the above step (a), with a lower alcohol represented by the formula 5, under an acidic condition, thereby producing a 3,3,3-trifluoro-2-hydroxypropionate represented by the formula 3; and
[0019] (c) reacting the 3,3,3-trifluoro-2-hydroxypropionate with a hydride reducing agent, thereby producing the 3,3,3-trifluoro-2-hydroxypropanol,
[0020] wherein R is a C 1 -C 6 lower alkyl group.
[0021] It is possible by the above step (c) to efficiently reduce the alkoxycarbonyl group (—CO 2 R) into the hydroxymethyl group (—CH 2 OH) using a hydride reducing agent (e.g., sodium borohydride), without necessity of protecting the hydroxyl group (bonded to the second carbon) of the raw material, 3,3,3-trifluoro-2-hydroxypropionate and without necessity of the following deprotection. Thus, it is possible to easily obtain 3,3,3-trifluoro-2-hydroxypropanol with high yield and less load in industrial production.
[0022] The above-mentioned exemplary hydride reducing agent, sodium borohydride, is low in price and easy for handling. Thus, this sodium borohydride is considerably superior in safety and economy to lithium aluminum hydride.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] In general, strongly basic condition (for example, having a pH of 12 or higher) has been considered as being not preferable for trifluoromethyl-containing compounds due to the tendency of decomposition of the trifluoromethyl group under such condition. The inventors, however, tried to bring the above 1,1-dihalogeno-3,3,3-trifluoroacetone into contact with a basic aqueous solution. With this, we unexpectedly found that the decomposition of the trifluoromethyl group does actually not occur and thereby the target product, 3,3,3-trifluoro-2-hydroxypropionic acid, can be obtained with high yield.
[0024] The above-mentioned steps (a), (b) and (c) for producing 3,3,3-trifluoro-2-hydroxypropanol can be shown by the following reaction scheme. As stated above, a target product of the present invention, 3,3,3-trifluoro-2-hydroxypropionic acid, can be obtained by the step (a).
[0025] The step (a) is described in detail as follows. It is possible to efficiently produce 1,1-dichloro-3,3,3-trifluoroacetone, which can be the raw material of the step (a), by a process of Japanese Patent Application Publication 10-287609, 10-330308, 11-001451 or 2000-063306, in which pentachloroacetone is fluorinated in a gas or liquid phase into 1,1-dichloro-3,3,3-trifluoroacetone. Similarly, it is possible to obtain 1,1-dibromo-3,3,3-trifluoroacetone and 1,1-diiodo-3,3,3-trifluoroacetone by fluorinating pentabromoacetone and pentaiodoacetone, respectively.
[0026] Although the obtained 1,1-dihalogeno-3,3,3-trifluoroacetone itself can be used as the raw material of the step (a), it can be used in the step (a) as a hydrate since it mixes freely with water. This hydrate is easy for handling and can have, for example, the following formula 6:
[0027] wherein X is defined as in the formula 1, and n is a number greater than 0. Furthermore, it is optional to mix 1,1-dihalogeno-3,3,3-trifluoroacetone with a solvent (e.g., alcohol) other than water to form a solvate. This solvate can also be used as the raw material of the step (a). Thus, 1,1-dihalogeno-3,3,3-trifluoroacetone of the formula 1 to be used in the step (a) is defined in the present specification as including its hydrate and solvate.
[0028] In case that 1,1-dihalogeno-3,3,3-trifluoroacetone is used as its hydrate in the step (a), the amount of water relative to that of 1,1-dihalogeno-3,3,3-trifluoroacetone for preparing the hydrate is not particularly limited. This water is in an amount of preferably 1-10 moles, more preferably 1-5 moles, relative to 1 mol of 1,1-dihalogeno-3,3,3-trifluoroacetone. A typical exemplary hydrate is a trihydrate in which 3 moles of water coexist with 1 mole of 1,1-dihalogeno-3,3,3-trifluoroacetone. This trihydrate is represented by the formula 6, in which n equals to 2. Using too much amount of water for preparing the hydrate is not problematic to the reactivity, but lowers the productivity. Therefore, it is not preferable.
[0029] The type of a base for preparing the basic aqueous solution of the step (a) is not particularly limited. It is preferably an inorganic base (e.g., sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, and potassium carbonate), in terms of reactivity and of preventing the production of impurities that are difficult to be separated from the target product. It is optional to combine a plurality of inorganic bases for preparing the basic aqueous solution. Of the above examples, sodium hydroxide and potassium hydroxide are preferable, since they are high in basicity and since pH of the resulting basic aqueous solution can easily be controlled. In particular, sodium hydroxide is more preferable.
[0030] In the step (a), the base concentration of the basic aqueous solution is not particularly limited and can suitably be set in view of solubility of the inorganic base in water. The base concentration is preferably 1-50 wt %, more preferably 1-40 wt %, of the basic aqueous solution.
[0031] The base of the basic aqueous solution may be in an amount of at least 2 equivalents, preferably 2-20 equivalents, more preferably 2-10 equivalents, relative to 1 equivalent of the compound of the formula 1.
[0032] The pH of the basic aqueous solution during the step (a) is preferably 12 or higher, more preferably 12-14, still more preferably 13-14. Although it may have a pH within these ranges by using the base in the above-described amount, it is preferable to measure pH of the reaction mixture at a suitable interval by using a known measure (e.g., pH test paper). In fact, pH of the reaction mixture (solution) gradually lowers as the reaction of the step (a) proceeds, since a halogenated hydracid (e.g., hydrochloric acid) is generated by the reaction. If the pH becomes too low, conversion and selectivity of the reaction become extremely low. Therefore, it is preferable in the reaction of the step (a) to measure pH of the reaction mixture at a suitable interval and to add the base to the reaction mixture when the measured pH is lower than 12.
[0033] It is optional to use a reaction solvent in the step (a). Its nonlimitative examples include (1) aliphatic hydrocarbons such as n-pentane, n-hexane, cyclohexane, and n-heptane; (2).aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; (3) halogenated hydrocarbons such as methylene chloride, chloroform, and 1,2-dichloroethane; (4) ethers such as diethyl ether, tetrahydrofuran, t-butyl methyl ether, and dioxane; (5) esters such as ethyl acetate and n-butyl acetate; (6) nitriles such as acetonitrile and propionitrile; (7) alcohols such as methanol, ethanol, n-propanol, and i-propanol; and (8) water. Of these, preferable examples are diethyl ether, tetrahydrofuran, t-butyl methyl ether, methanol, ethanol, i-propanol, and water. In particular, tetrahydrofuran, methanol, ethanol, and water are more preferable. It is possible to use a single solvent or a mixture of at least two of these. It is possible to conduct the reaction without using any reaction solvent.
[0034] The reaction temperature of the step (a) may be from −10° C. to +100° C., preferably −10° C. to +80° C., more preferably 0° C. to +60° C.
[0035] The way of adding the substrate is not particularly limited in the step (a). It is, however, preferable to add the substrate gradually in order to stably maintain the temperature of the reaction mixture, since the reaction of the step (a) generates a relatively strong heat. For example, the compound of the formula 1 may be added dropwise to the basic aqueous solution, or the basic aqueous solution may be added dropwise to the compound of the formula 1. In this case, the dropping rate may suitably be adjusted such that the inside temperature of the reactor does not become significantly higher than the outside set temperature. For example, it may be adjusted that the temperature difference between the inside and the outside is 10° C. or less.
[0036] In the reaction of the step (a), it is optional to stir the reaction mixture for about 1-3 hrs for ageing, after gradually adding the substrate. A stirring for a very long time (e.g., 24 hr or longer) may not further improve yield. Such stirring may lower the efficiency of the reaction and thus may not be preferable.
[0037] Post-treatment of the step (a) is not particularly limited. At the end of the reaction of the step (a), the target product, 3,3,3-trifluoro-2-hydroxypropionic acid represented by the formula 2, is present as a salt formed by a reaction of 3,3,3-trifluoro-2-hydroxypropionic acid with the base in an excessive amount. Thus, it is easily possible to add an inorganic acid to a reaction liquid obtained by the step (a) to convert this salt into 3,3,3-trifluoro-2-hydroxypropionic acid, followed by extraction with an organic solvent to isolate 3,3,3-trifluoro-2-hydroxypropionic acid. The inorganic acid may be selected from hydrochloric acid, hydrobromic acid, sulfuric acid, and phosphoric acid. Of these, hydrochloric acid and sulfuric acid are preferable, and hydrochloric acid is more preferable.
[0038] The above-mentioned extraction solvent may be selected from (1) aliphatic hydrocarbons such as n-pentane, n-hexane, cyclohexane, and n-heptane; (2) aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; (3) halogenated hydrocarbons such as methylene chloride, chloroform, and 1,2-dichloroethane; (4) ethers such as diethyl ether, tetrahydrofuran, t-butyl methyl ether, and dioxane; and (5) esters such as ethyl acetate and n-butyl acetate. Of these, preferable examples are toluene, t-butyl methyl ether, and ethyl acetate. In particular, t-butyl methyl ether and ethyl acetate are more preferable. It is possible to use a single solvent or a mixture of at least two of these.
[0039] In the step (a), the resulting extracted solution may be subjected to washing with water and brine, drying, and concentration, thereby obtaining a crude product. According to need, the crude product may be subjected to purification (e.g., the use of activated carbon, rectification, recrystallization, and column chromatography), thereby obtaining 3,3,3-trifluoro-2-hydroxypropionic acid of the formula 2 with high purity.
[0040] The step (b) is described in detail as follows. The step (b) can be conducted by reacting 3,3,3-trifluoro-2-hydroxypropionic acid, which has been obtained by the step (a), with a lower alcohol represented by the formula 5, in the presence of an acid catalyst, thereby producing 3,3,3-trifluoro-2-hydroxypropionate represented by the formula 3. The step (b) may be conducted in accordance with a conventional esterification.
[0041] The lower alcohol represented by the formula 5 may be selected from methanol, ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, i-propanol, 2-butanol, and cyclohexanol.
[0042] The lower alcohol of the formula 5 may be in an amount of 1 equivalent or greater, relative to 1 equivalent of 3,3,3-trifluoro-2-hydroxypropionic acid. In particular, it is possible to use an excessive amount of the lower alcohol as a reaction solvent.
[0043] The acid catalyst for conducting the step (b) may be selected from organic acids (e.g., benzenesulfonic acid, p-toluenesulfonic acid, 10-camphorsulfonic acid) and inorganic acids (e.g., hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, zinc chloride, and titanium tetrachloride). Of these, p-toluenesulfonic acid and sulfuric acid are preferable. In particular, sulfuric acid is more preferable.
[0044] The acid catalyst may be in a catalytic amount relative to that of 3,3,3-trifluoro-2-hydroxypropionic acid. It is preferably 0.001-1 equivalent, more preferably 0.005-0.5 equivalents, relative to one equivalent of 3,3,3-trifluoro-2-hydroxypropionic acid.
[0045] In the step (b), water is produced as a by-product as the reaction proceeds. It is possible to accelerate the reaction by removing such water from the reaction system. Thus, the reaction of the step (b) can be conducted in the presence of a dehydrating agent such as zeolite (e.g., molecular sieve), phosphorus pentoxide, anhydrous sodium sulfate, and anhydrous magnesium sulfate, to remove water during the step (b). In case that the lower alcohol of the formula 5 is immiscible with water, has a specific gravity less than that of water, and forms an azeotropic mixture with water, it is possible to remove water from a Dean-Stark trap, while the reaction is conducted under reflux with or without reaction solvent (e.g., benzene and toluene).
[0046] The reaction temperature of the step (b) may be from 0° C. to +200° C., preferably from 0° C. to +150° C., more preferably from 0° C. to +100° C. The reaction time for conducting the step (b) may be 48 hr or shorter and may vary depending on the reaction conditions. Therefore, it is preferable to terminate the reaction after confirming that the raw material was almost completely consumed, by checking the progress of the reaction by a suitable analytical technique (e.g., gas chromatography, thin layer chromatography, and NMR).
[0047] Post-treatment of the step (b) is not particularly limited. It is possible to easily obtain a crude product by subjecting a reaction mixture itself at the end of the reaction to distillation. This crude product can be used in the subsequent step (c). Alternatively, according to need, the crude product may be subjected to purification (e.g., the use of activated carbon, rectification, recrystallization, and column chromatography), thereby obtaining 3,3,3-trifluoro-2-hydroxypropionate of the formula 3 with very high purity.
[0048] The step (c) is described in detail as follows. As stated above, the step (c) can be conducted by reacting 3,3,3-trifluoro-2-hydroxypropionate of the formula 3 with a hydride reducing agent, thereby producing 3,3,3-trifluoro-2-hydroxypropanol of the formula 4.
[0049] The hydride reducing agent may be selected from (1) aluminum hydrides such as (i-Bu) 2 AlH, (i-Bu) 3 Al, [2,6-(t-Bu) 2 -4-MePh]Al(i-Bu) 2 , LiAlH 4 , LiAlH(OMe) 3 , LiAlH(O-t-Bu) 3 and NaAlH 2 (OCH 2 CH 2 OCH 3 ) 2 ; (2) boron hydrides such as diborane, BH 3 -THF, BH 3 -SMe 2 , BH 3 -NMe 3 , 9-BBN, NaBH 4 , NaBH 4 -CeCl 3 , LiBH 4 , Zn(BH 4 ) 2 , Ca(BH 4 ) 2 , Li(n-Bu)BH 3 , NaBH(OMe) 3 , NaBH(OAc)3, NaBH 3 CN, Et 4 NBH 4 , Me 4 NBH(OAc) 3 , (n-Bu) 4 NBH 3 CN, (n-Bu) 4 NBH(OAc) 3 , Li(sec-Bu) 3 BH, K(sec-Bu) 3 BH, LiSia 3 BH, KSia 3 BH, LiEt 3 BH, KPh 3 BH, (Ph 3 P) 2 CuBH 4 , ThxBH 2 , Sia 2 BH, catechol borane, IpcBH 2 and Ipc 2 BH; and (3) silicon hydrides such as Et 3 SiH, PhMe 2 SiH, Ph 2 SiH 2 and PhSiH 3 -Mo(CO) 6 , where Bu represents butyl group, Ph represents phenyl group, Me represents methyl group, THF represents tetrahydrofuran, 9-BBN represents 9-borabicyclo[3,3,1]nonane, Ac represents acetyl group, Sia represents siamyl group, Et represents ethyl group, Thx represents thexyl group, and Ipc represents isopinocampheyl group. Among these, LiAlH 4 , diborane, NaBH 4 and LiBH 4 are preferable. NaBH 4 is particularly more preferable, since it is low in price and can easily be used in a large amount. These hydride reducing agents can also be used in the presence of various inorganic salts.
[0050] The hydride reducing agent may be in an amount of 0.25 equivalents or greater, preferably 0.25-10 equivalents, more preferably 0.25-7.0 equivalents, relative to one equivalent of 3,3,3-trifluoro-2 -hydroxypropionate.
[0051] It is preferable to conduct the reaction of the step (c) in solvent. Its nonlimitative examples include (1) aliphatic hydrocarbons such as n-pentane, n-hexane, cyclohexane, and n-heptane; (2) aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; (3) halogenated hydrocarbons such as methylene chloride, chloroform, and 1,2-dichloroethane; (4) ethers such as diethyl ether, tetrahydrofuran, t-butyl methyl ether, and dioxane; (5) esters such as ethyl acetate and n-butyl acetate; (6) nitriles such as acetonitrile and propionitrile; (7) alcohols such as methanol, ethanol, n-propanol, and i-propanol; and (8) carboxylic acids such as acetic acid, propionic acid, and butyric acid. Of these, preferable examples are diethyl ether, tetrahydrofuran, t-butyl methyl ether, methanol, ethanol, and i-propanol. In particular, tetrahydrofuran, methanol, ethanol, and i-propanol are more preferable. It is possible to use a single solvent or a mixture of at least two of these.
[0052] The reaction temperature of the step (c) may be from −100° C. to +100° C., preferably −80° C. to +80° C., more preferably −60° C. to +60° C. The reaction time for conducting the step (c) may be 24 hr or shorter and may vary depending on the reaction conditions. Therefore, it is preferable to terminate the reaction after confirming that the raw material was almost completely consumed, by checking the progress of the reaction by a suitable analytical technique (e.g., gas chromatography, thin layer chromatography, and NMR).
[0053] In a reaction mixture at the end of the reaction of the step (c), 3,3,3-trifluoro-2-hydroxypropanol of the formula 4 is stably present as a five-membered cyclic compound represented by the formula 7.
[0054] Thus, the target product is still mostly in the form of the above five-membered cyclic compound, even if the reaction mixture obtained by the step (c) is extracted with organic solvent.
[0055] It is, however, possible to easily hydrolyze the five-membered cyclic compound by treating the same with an inorganic acid (e.g., hydrochloric acid, hydrobromic acid, sulfuric acid, and phosphorus acid) or fluoride ions, thereby isolate 3,3,3-trifluoro-2-hydroxypropanol. In fact, it is possible to add an inorganic acid to a reaction product (containing the five-membered cyclic compound) of the step (c), followed by heating at a constant temperature, thereby isolating the target product (i.e., 3,3,3-trifluoro-2-hydroxypropanol) with high yield. Although the way of this isolation is not particularly limited, it can effectively be conducted by dissolving the reaction product of the step (c) in methanol, then by adding a sulfuric acid aqueous solution, and then by heating under reflux.
[0056] It is possible to conduct a solvent extraction with an organic solvent to collect 3,3,3-trifluoro-2-hydroxypropanol, which has been isolated by the above-mentioned acid treatment. Examples of the organic extraction solvent include (1) aliphatic hydrocarbons such as n-pentane, n-hexane, cyclohexane, and n-heptane; (2) aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; (3) halogenated hydrocarbons such as methylene chloride, chloroform, and 1,2-dichloroethane; (4) ethers such as diethyl ether, tetrahydrofuran, t-butyl methyl ether, and dioxane; and (5) esters such as ethyl acetate and n-butyl acetate. Of these, preferable examples are toluene, diethyl ether, t-butyl methyl ether, and ethyl acetate. In particular, diethyl ether and ethyl acetate are more preferable. It is possible to use a single solvent or a mixture of at least two of these.
[0057] In the step (c), the resulting extracted solution may be subjected to washing with water and brine, drying, and concentration, thereby obtaining a crude product. According to need, the crude product may be subjected to purification (e.g., the use of activated carbon, rectification, recrystallization, and column chromatography), thereby obtaining 3,3,3-trifluoro-2-hydroxypropanol with high purity.
[0058] The following nonlimitative Examples are illustrative of the present invention.
EXAMPLE 1
[0059] The step (a) of the present invention was conducted as follows. At first, 235 g (1 mol, 1 eq.) of 1,1-dichloro-3,3,3-trifluoroacetone trihydrate were added dropwise by spending 2.5 hr to 533 g (4 mol, 4 eq.) of 30 wt % sodium hydroxide aqueous solution under cooling with ice, while the internal temperature of the reaction liquid was maintained at 25° C. or lower, followed by stirring for 1 hr. After that, 197 g (2 mol, 2 eq.) of 37 wt % hydrochloric acid aqueous solution were added dropwise to the reaction liquid under cooling with ice, while the internal temperature of the reaction liquid was maintained at 25° C. or lower. Then, 180 ml of water were added under room temperature to dissolve the precipitated sodium chloride. The resulting solution was extracted two times with 500 ml of ethyl acetate. Then, the combined organic layer was washed one time with 500 ml of saturated brine, concentrated and dried under vacuum, thereby obtaining 163 g of a crude product of 3,3,3-trifluoro-2-hydroxypropionic acid. This crude product was found by 1 H-NMR to contain 81.5 wt % of 3,3,3-trifluoro-2-hydroxypropionic acid (yield: 92%). This crude product was used in the following step (b) of Example 2 without conducting a further purification. The obtained 3,3,3-trifluoro-2-hydroxypropionic acid was found to have the following characteristics.
[0060] [0060] 1 H-NMR (standard substance: TMS; solvent: CD 3 OD), δ ppm: 4.53 (q, 7.6 Hz, 1H); 19 F-NMR (standard substance: C 6 F 6 , solvent: CD 3 OD), δ ppm: 87.75 (d, 7.6 Hz).
EXAMPLE 2
[0061] The step (b) of the present invention was conducted as follows. At first, 2.84 g of the crude product obtained by Example 1 (containing 16.07 mmol (1.00 eq.) of 3,3,3-trifluoro-2-hydroxypropionic acid) and 19.6 mg (0.20 mmol, 0.01 eq.) of 98% sulfuric acid were added to 20 ml of ethanol, followed by stirring for 43 hr with heating under reflux. The resulting reaction liquid itself was subjected to a vacuum distillation (52° C./3,500 Pa), thereby obtaining 1.87 g of white, needle-like crystals of ethyl 3,3,3-trifluoro-2-hydroxypropionate of the following formula 8. The yield was 68%. The obtained crude product (the white, needle-like crystals) was used in the following step (c) of Example 3 without conducting a further purification.
[0062] Ethyl 3,3,3-trifluoro-2-hydroxypropionate was found to have the following characteristics.
[0063] [0063] 1 H-NMR (standard substance: TMS; solvent: CDCl 3 ), δ ppm: 1.35 (t, 7.6 Hz, 3H), 3.42 (br, 1H), 4.30-4.47 (m, 2H), 4.47 (q, 7.6 Hz, 1H); 19 F-NMR (standard substance: C 6 F 6 , solvent: CDCl 3 ), δ ppm: 85.58 (d, 7.6 Hz).
EXAMPLE 3
[0064] The step (c) of the present invention was conducted as follows. At first, 1.87 g (10.87 mmol, 1.00 eq.) of the white, needle-like crystals of ethyl 3,3,3-trifluoro-2-hydroxypropionate, which had been produced in Example 2, were dissolved in 20 ml of ethanol. Then, 0.41 g (10.84 mmol, 1.00 eq.) of sodium borohydride were added under cooling with ice, followed by stirring at room temperature for 12 hr. Then, the reaction was terminated by adding 10 ml of 10 wt % hydrochloric acid aqueous solution, followed by adding 5 ml of water to dissolve undissolved substances. The resulting liquid was extracted two times with 20 ml of diethyl ether. The combined organic layer was washed one time with 10 ml of saturated brine. The resulting organic layer was dried with anhydrous sodium sulfate, concentrated and dried under vacuum, thereby obtaining an organic matter residue. This organic matter residue was found by 1 H-NMR to be formed mostly of a five-membered cyclic compound (represented by the following formula 9), obtained by a reaction of 3,3,3-trifluoro-2-hydroxypropanol with boron.
[0065] Then, to the total amount of the obtained organic matter residue 10 ml of methanol and 10 ml of 10 wt % sulfuric acid aqueous solution were added, followed by stirring for 24 hr with heating under reflux. After the reaction, methanol was distilled away, and the organic matter residue was dissolved by adding 20 ml of water. The obtained solution was extracted two times with 20 ml of diethyl ether. The combined organic layer was dried with anhydrous sodium sulfate, concentrated, dried under vacuum, and distilled under vacuum (62° C./1000 Pa), thereby obtaining 1.12 g of 3,3,3-trifluoro-2-hydroxypropanol as a purified distillate. The yield was 79%. The obtained 3,3,3-trifluoro-2-hydroxypropanol was found to have the following characteristics.
[0066] [0066] 1 H-NMR (standard substance: TMS; solvent: CDCl 3 ), δ ppm: 2.02 (br, 1H), 3.06 (br, 1H), 3.83-3.92 (m, 2H), 4.03-4.13 (m, 1H); 19 F-NMR (standard substance: C 6 F 6 , solvent: CDCl 3 ), δ ppm: 84.05 (d, 7.6 Hz).
[0067] The entire contents of Japanese Patent Application No. 2002-179554 (filed Jun. 20, 2002), which is a basic Japanese application of the present application, are incorporated herein by reference. | The invention relates to a process for producing 3,3,3-trifluoro-2-hydroxypropionic acid. This process includes the step of (a) bringing a 1,1-dihalogeno-3,3,3-trifluoroacetone into contact with a basic aqueous solution. The obtained 3,3,3-trifluoro-2-hydroxypropionic acid may be reacted with a C 1 -C 6 lower alcohol under an acidic condition, thereby producing a 3,3,3-trifluoro-2-hydroxypropionate. This propionate may be reacted with a hydride reducing agent (e.g., sodium borohydride), thereby producing 3,3,3-trifluoro-2-hydroxypropanol. These products (i.e., 3,3,3-trifluoro-2-hydroxypropionic acid and its derivatives) are important intermediates for medicines and liquid crystals. | 2 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] Embodiments of the present invention generally relate to a method and apparatus for temporarily sealing a bore of a tool. More particularly, the invention relates to a ball seat and a method and apparatus for remotely releasing the ball.
[0003] 2. Description of the Related Art
[0004] In the completion and operation of a hydrocarbon well, it is often necessary to remotely actuate a downhole tool in order to move the tool from a first to a second state. In one example, a packer is run into the well on a string of tubulars and then actuated, thereby causing sealing members to extend radially outwards into sealing contact with walls of the wellbore. One way of remotely actuating the tool is through a temporary increase in fluid pressure adequate to shift a piston formed on the tool that in turn causes the sealing members to move. In order to increase pressure in the area of the tool, the wellbore is typically blocked at a location below the tool. In one instance, the wellbore is blocked with a ball and ball seat. In one example, a ball is dropped from the surface of the well into the ball seat. With the bore blocked, pressure is increased to a point that sets the tool. Thereafter, pressure is increased to a higher level in order to “blow out ” the ball seat, permitting the ball to fall through the seat and the bore to be re-opened. While the forgoing arrangement is operable, it necessarily requires high pressures, especially to blow out the ball seat. High pressure can damage hydrocarbon-bearing formations through shock loading due to pressure surge or water hammer effect.
[0005] There is a need therefore, for a ball and seat arrangement wherein the ball can be released from the seat without the use of a fluid pressure differential across the seat.
SUMMARY OF THE INVENTION
[0006] The present invention generally relates to a downhole device for shifting a component from a first state to a second state. In one embodiment, the device includes a body having the component in a bore thereof and an annular space formed within an inner and outer wall of the body. The annular space includes a first fluid chamber in fluid communication with the bore at a first location and with a pressure transducer at a second location, the transducer constructed and arranged to measure pressure of the fluid and provide a signal to circuitry controlling a valve upon reception of a predetermined pressure pulse sequence. When the pulse sequence is delivered, the valve opens, placing a source of pressurized fluid in communication with an actuator that shifts the valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] 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.
[0008] FIG. 1 is a cross section view of a tool according to one embodiment of the invention.
[0009] FIG. 2 is a cross section view of the tool of FIG. 1 shown in a different rotational position.
[0010] FIG. 3 is a cross section view showing two portions of the tool in greater detail.
[0011] FIG. 4 is a cross section view showing a valve assembly with a valve shown in a closed position.
[0012] FIG. 5 is a cross section view showing the valve in an open position.
[0013] FIGS. 6 and 7 are section views of the valve in a different rotational position, shown in the open and closed positions, respectively.
[0014] FIG. 8 is a cross section view showing a lower portion of the tool including a ball seat with a ball held therein.
[0015] FIGS. 9 A-D are perspective views of the ball seat.
[0016] FIG. 10 is a cross section view shown the lower portion of the tool wherein the ball seat has been shifted to an enlarged diameter position.
DETAILED DESCRIPTION
[0017] The present invention relates to a downhole tool for temporarily blocking and un-blocking a flow path through a wellbore. More particularly, the invention relates to a ball and ball seat wherein the ball can be released from the seat without the use of a pressure differential across the seat.
[0018] FIG. 1 is a cross section view of a tool 100 according to one embodiment of the invention. The tool is constructed and arranged to be installed in a tubular string, typically production string (not shown) and is provided with threaded connections at an upper and lower ends. As shown, the tool includes a central bore 105 , the bore including a ball seat 200 , shown in a reduced diameter position with a ball 201 therein. In the position of FIG. 1 , the ball and ball seat are configured to block the bore 105 of the tool 100 and permit pressure to be developed in the wellbore at any location above the tool. Another tool needing pressure actuation would typically be disposed in the tubular string at a location above the tool 100 . The tool is constructed with an annular space formed between an inner 101 and outer 102 walls and in one embodiment of the invention; components are housed in the annular space. The various components are shown in greater detail in other Figures but the primary portions include a wellbore fluid chamber 110 , an annular piston 115 , a hydraulic fluid chamber 120 , electronic circuitry 125 and batteries 130 . Additionally, a number of interconnected fluid paths are formed in the annular space as well as a valve assembly 300 with a valve that is remotely openable to expose pressurized fluid in the fluid paths to an annular piston 150 that shifts the ball seat 200 to its larger diameter position in order to release the ball 201 and un-block the bore 105 .
[0019] FIG. 2 is a cross section view of the tool of FIG. 1 shown in a different rotational position and illustrates a first fluid path 250 (shown on the left side of the annular space) in greater detail. FIG. 3 is a cross section view showing two portions of the tool 100 in greater detail. In particular, the upper portion of the Figure illustrates an aperture 122 leading from the bore 105 of the tool to the annular wellbore fluid chamber 110 . The aperture 122 permits fluid pressure communication between the bore and the first fluid path 250 disposed in the annular area of the tool. As will be shown, the pressure of the fluid in the bore, and with it the pressure in the annular chambers 110 , 120 can be increased or decreased and delivered in pulses. A predetermined delivery of such pulses can be used to open the valve and ultimately shift the ball seat 200 from the smaller diameter position of FIG. 1 to a larger diameter position. Wellbore fluid chamber 110 is separated from hydraulic fluid chamber 120 by an annular piston 115 in order to prevent contamination of the hydraulic fluid while allowing it to be effected by pressure and pulses from the bore of the tool. The first fluid path 250 extends from the hydraulic fluid chamber 120 to a tubing pressure transducer 155 that is placed in the fluid path 250 where it receives and measures pressures and pulses in the bore of the tool as well as timing associated with those pressures and pulses and then generates an electrical signal based upon those values to circuitry 125 disposed in an adjacent area of the annular space ( FIG. 1 ). The first fluid path 250 is connected to a second fluid path 252 extending from one side of the annular space to the other. Located just above the tubing pressure transducer 155 on the left side of the Figure is a port 254 that leads into the second fluid path 252 around the annular body terminating at another port 255 visible on the right side of the Figure. Port 255 , in turn is connected to a third fluid path 256 that leads to the valve assembly 300 not visible in FIG. 3 but visible in FIG. 4 .
[0020] FIG. 4 is a cross section view showing the valve assembly 300 with a valve 302 shown in a closed position. As shown, the third fluid path 256 leads to the valve. In the embodiment shown, the valve assembly 300 includes a Kevlar fuse 350 which is designed to operate based upon an electronic signal from the on-board circuitry 125 in the tool 100 . The valve 302 includes a plunger 305 which in the closed position, blocks a fluid path through the valve 302 that otherwise connects the third fluid path entering the valve with a fourth fluid path 258 leading from valve. The plunger 305 is biased towards an open position due to a spring 306 but is initially held in a closed position, against the force of the compressed spring by retaining members 310 that are equipped with electrodes (partially shown) 312 causing them to fail in the event of a predetermined electrical signal from the circuitry 125 . One example of a Kevlar fuse-type device is shown and described in U.S. Pat. No. 5,558,153 and that patent is incorporated by reference in its entirety herein.
[0021] FIG. 5 is a cross section view showing the valve 302 in an open position. As shown, the retaining members 310 have been caused to fail and the plunger 305 has been moved from a first closed position ( FIG. 4 ), in which port 257 is blocked by the plunger 305 , to an second, open position ( FIG. 5 ) wherein fluid traveling in port 257 is free to enter and pass through the valve due to the extended spring 306 which was initially held in a compressed position. FIGS. 6 and 7 are section views of the valve assembly 300 from a different rotational position, shown in the open and closed positions, respectively. Visible in each is the valve 302 with its plunger 305 biased by the spring 306 . In FIG. 6 the port 257 (not shown) leading into the valve is blocked by a plunger member 307 . In FIG. 7 however, port 257 is visible and the fluid therein is in communication with the fourth fluid path 258 leading out of the valve.
[0022] FIG. 8 is a cross section view showing a lower portion of the tool 100 including ball seat 200 with ball 201 held therein. The ball seat is constructed of a plurality of castellations 202 , equally spaced around a perimeter of a sealing ring 205 and more completely illustrated in FIGS. 9 A-D, which include various perspective views of the ball seat 200 . Each castellation 202 has an angled inner surface 203 and is mounted at a lower end to a sealing ring 205 . The ring 205 includes at least one O-ring (visible in FIGS. 8, 10 ) for sealing against an upwardly facing shoulder 207 formed in the body of the tool and constructed and arranged to retain and seal the ball seat 200 in the bore 105 of the tool 100 . The purpose of the angled inner surface 203 of each castellation 202 is to mate with and move upwards relative to a conical surface 210 formed on an outer diameter of a sleeve 211 installed in the bore 105 of the tool above the ball seat 200 . Visible in FIG. 8 is an annular shifting piston 150 with a piston surface 152 formed on a lower end thereof and in communication with the lower end of fourth fluid path 258 extending from the valve 302 (when the valve is open). A space 153 above the piston 150 is filled with air at atmospheric pressure permitting the gap to be reduced in volume as the piston moves.
[0023] FIG. 10 is a cross section view showing the lower portion of the tool 100 wherein the ball seat 200 has been shifted to an enlarged diameter position. As shown, the annular shifting piston 150 has moved from a first lower to a second higher position relative to the ball seat due to fluid pressure acting on the piston surface 152 of the piston 150 . Consequently, the space 153 has been reduced in volume. In operation, an upwardly facing shoulder 154 of the annular piston 150 that is in contact with a lower surface 212 of the castellations 202 has forced the ball seat 200 with its castellations 202 upwards along the conical surface 210 , thereby enlarging the inner diameter of the sealing ring 205 to a size exceeding the outer diameter of the ball 201 . In this manner, the ball is released and fluid communication is reestablished between the portions of the bore above and below the ball seat 200 .
[0024] In one embodiment, the invention is practiced in the following manner: A tool 100 including the ball 201 and ball seat 200 is run into a wellbore in a string of tubulars to a predetermined depth. The ball seat is in its smaller diameter position as shown in FIG. 1 , however, the bore through the tool is open because there is no ball in the seat during run in. At some later time, an operator decides to set a pressure-actuated tool, like a packer disposed in the string above the tool 100 . A ball is dropped from the surface and lands in the seat as shown in FIG. 1 . With the bore of the tool blocked, pressure in the tubular string is increased to a predetermined threshold, typically by pumping from the surface, until the pressure-actuated tool is set. Thereafter, there is a need to remove the ball from the seat and reopen the bore through the tool.
[0025] In one embodiment, the ball seat 200 is shifted from its smaller to larger diameter state based upon predetermined parameters consisting of signals to circuitry 125 housed in the tool. Those signals begin as pressure pulses delivered to the tubing pressure transducer 155 from the bore of the tool via aperture 122 ( FIG. 3 ). A complete “pulse” in one instance is a specified pressure applied via the tubing to the tubing pressure transducer followed by a “bleeding off” of that pressure to zero. In one example, the circuitry is programmed to operate the Kevlar fuse of the valve assembly 302 in the event that it receives data from the transducer 155 indicating three separate and distinct pulses have been received. In another example, the data includes not only pulses but pulses separated by a predetermined time delay in seconds or minutes. Additionally, the circuitry can include programming that delays the operation of the fuse for a predetermined period of time after the data has been received. Numerous variations are available limited only by the ability to provide pulses from the bore of the tool to the transducer 155 . In one embodiment, an annulus pressure transducer 156 ( FIG. 1 ) is provided. The annulus pressure transducer is in fluid communication with the annulus between the tool 100 and the wellbore walls. By calculating the difference between tubing and annulus pressure, an effective pressure can be determined and that effective pressure data provided to the circuitry for operation of the valve assembly 302 with its Kevlar fuse.
[0026] Once conditions for operation of the Kevlar fuse have been met, the electrodes operate to break the retaining members retaining the valve 302 in a closed position and the valve moves from the closed position of FIG. 4 to the open position of FIG. 5 . As described in conjunction with FIG. 5 , the open valve permits fluid to flow into the fourth fluid path 258 to the annular shifting piston 150 , thereby moving the ball seat from the position of FIG. 8 to the position of FIG. 10 . With the seat 200 in its larger diameter position, the ball 201 is released, the bore 105 unblocked and wellbore operations can be resumed without having subjected the wellbore and surrounding formations to a pressure surge.
[0027] 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. | A downhole device shifts a component from a first state to a second state. In one embodiment, the device includes a body having the component in a bore thereof and an annular space formed within an inner and outer wall of the body. The annular space includes a first fluid chamber in fluid communication with the bore at a first location and with a pressure transducer at a second location, the transducer constructed and arranged to measure pressure of the fluid and provide a signal to circuitry controlling a valve upon reception of a predetermined pressure pulse sequence. When the pulse sequence is delivered, the valve opens, placing a source of pressurized fluid in communication with an actuator that shifts the valve. | 4 |
This invention relates to an improved process for preparing valuable terpene alcohols from acyclic terpene allylic halides. More specifically this invention relates to an improved process for preparing unsaturated terpene alcohols such as:
A. myrcenol (2-methyl-6-methylene-7-octene-2-ol). ##SPC1##
B. cis-ocimenol (cis-2,6-dimethyl-5,7-octadiene-2-ol). ##SPC2##
C. trans-ocimenol (trans-2,6-dimethyl-5,7-octadiene-2-ol). ##SPC3##
Terpene alcohols of the type produced by this invention are especially valuable because of their fragrance. Their odors are useful in citrus and floral fragrances employed in cosmetic and soap manufacture. Ocimenol, in particular, is especially prized in perfume compositions. Ocimenol is said to offer "new tonalities, freshness and rich cool notes, unobtainable with the natural citrus oil" in "Perfume and Flavor Chemicals" by S. Arctander (1969) no. 2389. Additionally, the esters of myrcenol and ocimenol are much prized for their odors.
Prior art processes for the manufacture of these terpene alcohols have suffered from many disadvantages. Processes for the production of myrcenol as described in U.S. Pat. Nos. 2,871,271 and in 2,947,780 give mixtures containing major quantities of other less desirable alcohols. Another process described in U.S. Pat. No. 3,075,003 produces none of the more desired alcohol, ocimenol. Moreover, this process requires highly specialized manufacturing equipment consisting of a low vacuum "wiping" still for the purification of intermediates. In yet another process, described in U.S. Pat. No. 3,549,679, it is necessary to use large quantities of a toxic and expensive compound, iron pentacarbonyl to produce myrcenol. Further, the process of that patent also gives none of the more valuable ocimenol. The process described in U.S. Pat. No. 3,344,171 requires the use of precious metals such as rhodium and iridium for the production of ocimenol. Moreover, the theory yield of ocimenol from myrcenol by this process is reported to be only 60%.
In summary, prior art processes for the manufacture of unsaturated terpene alcohols have encountered numerous problems and disadvantages such as (a) low yields, (b) impure mixtures of terpene alcohols containing major quantities of less desirable alcohols, (c) the need for expensive highly specialized process equipment, (d) high inefficiency, (e) require the use of expensive catalysts such as precious metals and/or toxic ingredients and (f) unstability of unsaturated terpene alcohols in that they tend to polymerize readily due to its conjugated double bond.
It is an object of this invention to provide an improved process for the production of unsaturated terpene alcohols such as myrcenol and cis and trans-ocimenol and mixtures thereof. It is a further object of this invention to provide a highly efficient commercially feasible process for the synthesis of unsaturated terpene alcohols such as myrcenol and cis and trans-ocimenol of high purity without the aforementioned problems of the prior art.
BRIEF DESCRIPTION OF THE INVENTION
Unsaturated terpene alcohols (conjugated dienic terpene alcohols) such as myrcenol and cis and trans-ocimenol are prepared by quaternizing an acyclic terpene allylic halide such as neryl, geranyl, and linalyl halides and mixtures thereof with a tertiary amine to form the corresponding quaternary ammonium salt. The tertiary amines useful for this invention are represented by the following formula: ##EQU1## wherein (a) R 1 , R 2 and R 3 are lower alkyl groups having 1-2 carbon atoms, (b) R 1 and R 2 are joined as a heterocyclic residue and R 3 is a lower alkyl having 1-2 carbon atoms, (c) R 1 and R 2 are lower alkyl groups having 1-2 carbon atoms and R 3 is a cycloalkyl, aralkyl or aryl carbon compound.
After quaternization, the quaternary ammonium salt of the terpene allylic halide is acidified by adding an aqueous acid medium to the reaction mixture thereby removing the ethylenic un-saturation, between the 6th and 7th carbon of the terpene allylic halide salt and adding an hydroxy substituent on the 7th carbon of the terpene halide salt. Following hydration is neutralization of the hydroxy substituted terpene quaternary ammonium salt by base or aqueous alkaline solution and thereafter thermally decomposing the neutralized hydroxy substituted terpene quaternary salt to form the unsaturated terpene alcohols.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the invention, the first step of the process for preparing the unsaturated terpene alcohols such as myrcenol and ocimenol (cis and trans) is the quaternization step. An halo-substituted acyclic terpene is reacted with a tertiary amine of the formula heretofore described to form a quanternary ammonium salt of the terpene halide. Typical halo-substituted acyclic terpenes also referred to as acyclic terpene allylic halides which can be used for the quaternization reaction are linalyl halides, geranyl halides, and neryl halides. One common source of linalyl, geranyl, and neryl chlorides is the hydrochlorination of commercial myrcene using a copper catalyst to form crude myrcene hydrochloride described in U.S. Pat. No. 2,882,323. Myrcene hydrochloride contains about 60% neryl and geranyl chloride, 10% linalyl chloride, about 10-15% non-allylic terpene chlorides and the remainder is a mixture of terpene hydrocarbons. Myrcene hydrochloride is an intermediate produced in large volume for the synthesis of nerol, geraniol and citral. The following chemical reaction is illustrative of the quaternization step when neryl and geranyl chlorides are employed. ##SPC4## ##SPC5##
Mixtures of acyclic terpene allylic halides are also reacted with the tertiary amine to form the quaternary ammonium salt of the terpene halide. Generally, the amount of tertiary amine reacted with the acyclic terpene allylic halide is not critical, usually an excess of the stoichiometric amount necessary for the quaternization reaction, from about 1.01 to about 2.00 moles per mole of the acyclic terpene allylic halides. The preferred ranges are 1.1 to 1.2 moles of the amine per mole of the terpene halide. Any excess tertiary amine used in the reaction can be readily recovered by known procedures.
Tertiary amines useful for the quaternization reactions are represented by the formula: ##EQU2## wherein (a) R 1 , R 2 and R 3 are lower alkyl groups having 1-2 carbon atoms, (b) R 1 and R 2 are joined as a heterocyclic residue and R 3 is a lower alkyl having 1-2 carbon atoms, (c) R 1 and R 2 are lower alkyl groups having 1-2 carbon atoms and R 3 is a cycloalkyl, aralkyl or aryl carbon compound.
Tertiary amines useful for this reaction are those which generally give satisfactory rates of quaternization of alkyl halides. Typical of such amines represented by the formula heretofore described are aliphatic amines, such as trimethylamine, triethylamine and methyldiethylamine. Cyclic aliphatic amines such a N-methyl-piperidine and N-methyl morpholine are also effective. Examples of other effective amines are N-N-dimethylcyclohexylamine and N,N-dimethyl benzylamine. Sterically hindered tertiary amines, such as tri-n-butylamine, N-cyclohexyl morpholine, N-methyl-dicyclohexylamine and N-cyclohexyl piperidine as well as tertiary-aromatic amines such as dimethylaniline, are useful, but only with long reaction times. Trimethylamine is the preferred tertiary amine for reasons of economy. Further, because trimethylamine has no hydrogens on a beta-carbon, the resultant quaternary ammonium hydroxide can eliminate in only one direction and thus give improved yields.
Quaternization temperature can range from -20°C to 100°C. Temperatures in the range of 20° to 60°C are preferred.
The quaternary ammonium salt of the terpene halide is a solid which precipitates as a product from the quaternization reaction. If the reaction mixture becomes too thick, solvents such as a mixture of menthadienes or aliphatic and aromatic hydrocarbons may be added to make the reaction mixture more fluid. Alternatively, water may be incrementally added. The amount of water is not critical. The amount would further depend on the nature of the quaternary ammonium salt. About 8% water based on the weight of myrcene hydrochloride is sufficient to form an aqueous solution of the trimethyl quaternary ammonium chloride. Additional quantities can be used but are not preferred because large quantities would promote the hydrolysis of terpene allylic halides to the corresponding alcohols. Quaternization reaction time is complete when all the allylic terpene halides are absent from the reaction mixture. The progress of the reaction can be monitored by removing samples from the oil phase and determining the concentration of the allylic halides by vapor phase chromatography or infra-red analysis.
STEP II -- HYDRATION REACTION
Following quaternization is hydration of the quaternary ammonium salt of the terpene halide with an aqueous acid to form a hydroxy substituent on the seventh carbon atom. The quaternary ammonium salts from the quaternization step are solid compounds and were found to be highly water soluble. This high water solubility has two valuable features. One, the water solubility facilitates a more rapid hydration of the 6,7-double bond. Secondly, the quaternary ammonium salts can be purified easily from the unreacted chloride compounds and hydrocarbons, originally present in the crude myrcene hydrochloride which are not water soluble. The following reaction is illustrative of the hydration step: ##SPC6##
The hydration reaction is started after the termination of the quaternization reaction by the addition of water and acid to catalyze hydration. Acids useful for the hydration are mineral acids such as HCl, H 2 SO 4 , and H 3 PO 4 .
The normality of the acid used for hydration ranges from 1.0 N to 6.0 N. Preferred acid normality is 1.2 N to 3.0 N. The amount of water added is not critical. For economy and efficiency water is added first to dissolve the quaternary ammonium terpene halide salt in an aqueous solution and to separate any hydrocarbons and terpene non-allylic halides in a separate oil layer.
The aqueous layer is then washed with a suitable paraffinic or aromatic hydrocarbon solvent to remove the last traces of any unreacted terpene compounds. Generally the temperature of hydration ranges from 15° to 60°C. Preferred temperature is room temperature. Time of the hydration reaction is dependent upon normality of the acid used.
One normal acid will give complete hydration in 24 hours at 25°C. If 3.4 N acid is used, hydration is complete in 4 hours.
The progress of the hydration step may be followed by removing a sample from the reaction and subjecting it to heat in the presence of aqueous alkali. The volatile oil formed is then analyzed by vapor phase chromatography to determine the degree of hydration of the 6,7-double bond.
STEP III -- NEUTRALIZATION
Following the hydration step the aqueous layer is neutralized with solid base or an aqueous alkaline solution (See Chart I). Performance of this step is not critical but for best yields it is preferred that the aqueous solution of the hydrated quaternary ammonium compounds be neutralized before subjecting this solution to the conditions of the next step. In the decomposition the temperature is elevated and if the acidic aqueous solution is momentarily heated to an elevated temperature, there results some dehydration of the 7-hydroxy substituent on the allylic terpene quaternary ammonium compound. The terpene alcohols can be made without the neutralization step but neutralization is preferred for economy, efficiency and higher yields.
The base may be added as a solid or as an aqueous solution. The concentration of the base may be 100%-5%. Preferably a sodium hydroxide solution having a concentration between 10% and 30% is employed for efficiency and economy. Similar results were obtained with other concentrations and with other bases such as potassium hydroxide or sodium carbonate. The neutralization can be carried out at temperatures between -15° and 60°C. Preferably the hydroxy substituted terpene quaternary ammonium salt solution is cooled to about room temperature, 25°C, during neutralization.
During neutralization the quaternary ammonium hydroxide of the hydroxy substituted terpene is formed. However, it is postulated that it may not be exclusively in the hydroxide form. The reaction mixture may contain terpene quaternary ammonium hydroxide in the form of a solution of ions.
STEP IV -- THERMAL DECOMPOSITION
The final step of the process is the thermal decomposition of the quaternary ammonium hydroxide of the hydroxy substituted terpene. (See Chart I). Thermal decomposition was accomplished at a temperature range of above about 100°C to below about 170°C. The preferred temperature of decomposition is 125°C to 140°C. The rate of decomposition was found to be slow below 110°C.
The quaternary ammonium hydroxide is decomposed for convenience preferably in the presence of sodium hydroxide solution. Alternately, the quaternary ammonium hydroxide can be heated alone in order to bring about decomposition. This latter alternative is commercially less attractive because of the difficulty of isolating the quaternary ammonium hydroxide.
In the preferred manner of operation, the neutralized aqueous solution of the quaternary ammonium salt is fed to a refluxing solution of a base, such as sodium hydroxide or potassium hydroxide, at a rate proportional to the rate of steam distillation of the myrcenol and ocimenol from the decomposition.
In order to achieve more rapid rates of decomposition, the reaction temperature must be in the vicinity of at least 120°C. To achieve such a temperature, the sodium hydroxide solution must be at least 25% in concentration. Weaker concentrations tend to give lower reflux temperatures and thus slower rates. Good results are obtained using solutions containing 50-60% aqueous alkali which give reflux temperatures of 135° to 140°C. The preferred range is 125° to 140°C. Concentration of 10-70% can be used.
The ratio of myrcenol to cis and trans-ocimenol was found to be dependent upon the concentration of the alkaline solution employed during the thermal decomposition. The amount of myrcenol increased with decreasing concentration of alkali. For example, when an alkaline solution was employed having a concentration of 50-60% during the thermal decomposition reaction the product ratio was 60% myrcenol and 40% cis and trans-ocimenol. When an alkaline solution having a concentration of 25% was employed, the ratio was 80% myrcenol and 20% cis and trans-ocimenol.
The rate of decomposition is dependent primarily upon the temperature of decomposition. When the temperature of the reaction is less than 110°C, decomposition is slow. Optionally, the rate of decomposition can be increased by the addition of high boiling solvent such as ethylene glycol, or by the addition of neutral salts such as NaCl, Na acetate, sodium formate and sodium phosphate.
As the quaternary ammonium hydroxide decomposes, the unsaturated terpene alcohol products formed are readily separated by conventional phase separation methods such as steam distillation, decantation, cohobation; unsaturated terpene alcohols are advantageously removed from the alkaline solution rapidly to prevent polymerization. ##SPC7##
The following examples show ways in which the invention has been practiced but should not be construed as limiting the invention. All parts are parts by weight and all temperatures are degrees Centigrade unless otherwise indicated.
EXAMPLE 1
The starting material, prepared by hydrochlorination of commercial myrcene using a copper catalyst, contained about 10% linalyl chloride and 60% neryl and geranyl chlorides, about 10-15% non-allylic terpene chlorides and the remainder was a mixture of various terpene hydrocarbons.
Trimethylamine (285 grams) was added gradually over 4 hours at 20°-30°C to 1000 grams myrcene hydrochloride. In order to make the reaction more fluid, 500 grams of a mixture of terpene hydrocarbons is added to the reaction at the beginning. The reaction mixture containing solid quaternary ammonium chlorides was stirred for an additional 16 hours at 20°-30°C. Then 1000 grams of water was added to dissolve the solid.
The oil layer containing terpene hydrocarbons and unreactive terpene chlorides after separation weighed 766 grams. The water layer was washed once with 200 grams of heptane to remove occluded oils. The water layer, which weighed 2019 grams, was diluted with 1615 grams of water and acidified with 385 grams 37% aqueous hydrochloric acid. The mixture was allowed to stand for 24 hours. The normality of the acid layer was 1.3N.
The solution was then carefully made alkaline at 25°C with cooling by the addition of an aqueous solution containing 324 grams of sodium hydroxide. The hydrated geranyl trimethyl ammonium hydroxide remained dissolved in the water layer.
The aqueous solution was then added gradually to a refluxing solution of 1800 grams sodium hydroxide in 2700 grams of water. The rate was such that the volatile alcohols, formed on decomposition, could be readily removed by steam distillation. The decomposition temperature was maintained at 120°-130°C.
A total of 669 grams of steam distilled alcohols was obtained. Vapor phase chromatographic analysis showed the myrcenol content to be 80% and the cis- and trans-ocimenols to be 20%.
EXAMPLE 2
Trimethylamine (340 grams) was added to 1000 grams of myrcene hydrochloride under the same conditions as in Example 1. The reaction was then diluted with 1000 grams of water. The unreacted oils, including the 500 grams of terpene hydrocarbons which were added during the trimethylamine addition, were not separated from the oil layer.
To the reaction was then added 600 grams 37% hydrochloric acid solution. The normality of the water layer was 2.6N. Analysis of the water layer after 6 hours indicated that the hydration was complete.
The water layer was then separated from the oil layer which weighed 757 grams. The water layer after washing with 200 grams heptane was carefully made alkaline (pH greater than 9) using cooling at 25°C. with the addition of 290 grams NaOH (97%).
The water layer, now weighing 2973 grams, was added gradually to a refluxing solution of 300 grams NaOH, 615 grams sodium acetate and 900 grams of water. The temperature of the decomposition was maintained between 125°-130°C. At completion the steam distilled oil weighed 540 grams and analyzed 79.4% myrcenol and 18.6% cis- and trans-ocimenols.
The alcohol product may then be given a distillation at reduced pressure to produce perfume quality myrcenol and ocimenols. An oxidation inhibitor such as 2,6-dibutyl-p-cresol can be added to the distillation to give better yields.
The alcohol product also may be reacted with acetic anhydride at room temperature with a few precent mineral acid catalyst. After a suitable reaction period, the reaction is washed up and the mixed acetates are distilled to give a perfume grade mixture of myrcenyl and cis- and trans-ocimenyl acetates.
EXAMPLE 3
Trimethylamine (285 grams) was added to 1000 grams of myrcene hydrochloride over 4 hours at 20°-30°C. The reaction was made more fluid by the addition of 500 grams of mixed terpene hydrocarbons. After 16 hours, 1000 grams of water was added with mixture. The separated oil layer weighed 766 grams and the water layer after washing with 200 grams heptane weighed 2019 grams. The water layer was then diluted with 2000 grams water and acidified with 393 grams of 37% hydrochloric acid. After 24 hours at room temperature, the hydration was virtually complete.
Then the water layer was made very strongly alkaline (pH 14) by the gradual addition of 1023 grams of sodium hydroxide. The hydrated quaternary ammonium compounds separated as a thick, oil layer. This oil layer, after separation, weighed 1958 grams.
The oil layer was then fed gradually to a refluxing solution of 900 grams sodium hydroxide, 1845 grams sodium acetate and 2700 grams water. The oil distillate weighed 573 grams and contained 79.2% myrcenol and 20.8% cis- and trans-ocimenols. Much of the aqueous distillate was returned to the decomposition vessel so as to maintain a reaction temperature of 125°-130°C.
EXAMPLE 4
The conditions of Example 3 were repeated except that the hydroxygeranyltrimethylammonium hydroxide oil layer was decomposed to alcohols by gradually adding it to a refluxing solution of 300 grams sodium hydroxide and 2982 grams ethylene glycol. The temperature of the decomposition was maintained at 165°-170°C. throughout the run. The crude product weighed 591 grams and contained 81.9% myrcenol and 17.3% ocimenols.
EXAMPLE 5
Trimethylamine (294 grams) was added gradually to a mixture of 1000 grams of myrcene hydrochloride and 80 grams of water at 20°-30°C. over 4 hours. The reaction was then stirred for an additional 16 hours at about 25°C. The reaction mixture remained fluid throughout.
To the mixture was added 1160 grams of water. The aqueous layer after separation weighed 1914 grams and the oil layer weighed 304 grams. VPC analysis of the oil layer showed no unreacted terpene allylic chlorides and only traces of alcohols.
The aqueous layer was washed with 100 grams of heptane to remove occluded oils and then acidified with 225 grams of 37% hydrochloric acid solution. The hydration was virtually complete after 24 hours at room temperature.
The solution was neutralized by the gradual addition of 215 grams of sodium hydroxide with agitation and cooling. The neutralized solution was then fed gradually to a refluxing solution of 1040 grams NaOH in 975 grams of water. A total of 526 grams of alcohol mixture was obtained which by VPC analysis contained 3.1% hydrocarbons, 63.5% myrcenol and 33.4% ocimenols. | An improved process for the preparation of unsaturated terpene alcohols such as myrcenol and cis and trans ocimenol is described. Acyclic terpene allylic halides are reacted with a tertiary amine of the formula hereinafter described to form the corresponding quaternary ammonium salt which is then acidified to remove the ethylenic unsaturation between the 6th and 7th carbon atom and adding a hydroxy substituent on the 7th carbon atom of the terpene halide salt. The hydrated terpene ammonium halide salt is made neutral and thermally decomposed into the unsaturated terpene alcohols. Myrcenol and ocimenol cis and trans are useful for their fragrance and aroma in perfumery and cosmetic manufacture. | 2 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a divisional application of U.S. Ser. No. 08/713,526 filed on Sep. 13, 1996 now U.S. Pat. No. 5,769,822 and entitled "Non-Reusable Retractable Safety Syringe".
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to a syringe device and, more particularly, to a non-reusable retractable syringe having an automatically retracting hypodermic needle to prevent reuse of the syringe. A method for delivering fluid to a patient and retracting the needle within the syringe after the fluid is delivered is disclosed.
(2) Description of Problems and the Prior Art
Many communicable diseases are commonly spread by contacting bodily and/or medicinal fluids of an infected person, reuse of hypodermic syringes is one of the most common causes of such contact.
Various mechanisms are provided in medical facilities for the disposal or destruction of syringes and hypodermic needles after usage. However, it is not uncommon for a medical worker to be scratched or punctured by a needle after usage and before disposal, resulting in injury and exposure to disease. Accordingly, there exists a need to protect personnel from accidental skin injuries from such contaminated needles, as well as the need to provide a safe and efficient means for disposing of the needles themselves.
There has been increased emphasis in designing hypodermic syringes with extendible shields which protect and project over the needle area after injections are completed. Such devices often involve manual manipulation of the shield over the needle after the injection is completed. It follows that when the shield is manually extended over the needle, the operator's hands or fingers may come into contact with the tip of the needle, thus causing risk of infection. To correct this problem, many devices have built-in biasing means which provide a shield over the needle after the injection is completed.
In U.S. Pat. No. 5,053,010, entitled "Safety Syringe with Retractable Needle", issued Oct. 1, 1991, there is shown and disclosed an improved safety syringe with retractable needle which allows retraction of the needle into a hollow plunger by additional forward pressure on the plunger after fluid is driven from the syringe into the patient. The syringe includes a hollow plunger which is inserted into one end of a cylindrical barrel and a hollow needle attached to the other end of the barrel. Biasing means are attached to the barrel for biasing the needle towards the hollow plunger, and means are provided for releasing the needle into the hollow plunger by applying additional forward pressure upon the plunger after the plunger is telescopically contracted relative to the barrel. This design, as well as others which are commercially available, provide a plunger which is made of a plastic material, such as polypropylene, which is manufactured by known techniques. Typically carried thereon is a sealing element which is made of a comparatively soft elastomeric material, which forms the seal between the housing and the moving plunger, to prevent leakage therebetween of the fluid to be injected.
The design disclosed in U.S. Pat. No. 5,053,010 incorporates a sliding elastomeric seal which displaces from its forward position to a retracted position, thereby allowing additional forward travel of the plunger to actuate the retraction mechanism. However, with this configuration, the soft nature of the seal depicted could allow it to slide prematurely during an injection. Increasing the stiffness of the sealing member would reduce the tendency to slide prematurely, but at the expense of the seal integrity.
There is need for an improved design of syringe in which an elastomer or other relatively soft seal can be used to provide maximum sealing integrity while also permitting sufficient pressure to be applied through the device to complete the injection, and thereafter to permit a cutter operatively associated with the plunger to continue to travel to cut the seal and, in turn, initiate retraction of the needle into the device after completion of the injection.
Moreover, it has been found desirable to prevent telescopic expansion of the plunger relative to the barrel of the device after activation of the retraction mechanism to assure that the needle tip cannot easily be re-exposed through withdrawal of the plunger.
SUMMARY OF THE INVENTION
The present invention provides a non-reusable retractable safety syringe. A cylindrical barrel is provided which has first and second barrel ends and an inside diameter wall there between. A chamber is provided for receipt of fluid within the barrel and between the first and second barrel end. A plastic hollow plunger is fully extendible into the barrel and is inserted into the first end of the barrel. The plunger is selectively movable from expanded position toward and placeable into an expended position. Thereafter, the plunger may be moved to a fully collapsed position relative to the second end of the barrel.
A hollow needle is secured relative to the second end of the barrel. Biasing means are provided in an initially secured relationship relative to the second end of the barrel for biasing the needle toward the hollow plunger. Means are provided for directing forward pressure upon the plunger, and sealing means include an elastomeric sealing member which is engaged to one end of the plunger for slidable sealing engagement with the inside diameter wall of the barrel. A cutting tip is provided and is carried by the plunger for cutting through the sealing member such that the biasing means releases the needle into the plunger when the plunger is at the fully collapsed position relative to the second end of the barrel.
The plunger may also include the sealing means which is engaged to one end of the plunger when the plunger is in the expanded and expended positions, as well as when the plunger is moving toward the collapsed position, with the sealing means being disengageable from one end of the plunger during movement of the plunger toward, but prior to, the plunger being placed at the collapsed position.
The syringe may comprise one of a number of engaging means for securing the plunger relative to the sealing means.
Fluid is drawn into the syringe through the needle. The needle is then implanted into the patient and the medication delivered via one-handed force applied to one end of the plunger--moving the plunger and sealing means to the expended position.
While or after removing the needle from the patient, additional one-hand force is applied to the plunger to move the plunger into the collapsed position. As the plunger collapses, the cutting tip extends through the sealing means and then through the needle retaining element to thereby release the biased needle into the plunger element of the device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a horizontal, sectional view of the device of the present invention prior to usage and, further, prior to introduction of medication therein.
FIG. 2 is a view similar to that of FIG. 1 showing the device with the plunger expanded and medication filling the interior portion of the chamber.
FIG. 3 is a view similar to those of FIGS. 1 and 2 showing the plunger collapsed within the barrel after medication has been injected into the patient, with the needle being retracted into the interior of the plunger, and the plunger being moved to the locked position.
FIG. 4 is a partial sectional view of a preferred means for securing the plunger relative to the sealing means.
FIG. 5 is a partial horizontal sectional view of the device in FIG. 1, illustrating an alternate preferred embodiment means for securing the sealing means to the plunger.
FIG. 6 is a cross-sectional view of the device of FIG. 5 taken along lines 6--6 of FIG. 5.
FIG. 7 is a view similar to FIG. 5 showing movement of the cutter through the sealing means.
FIG. 8 is a partial horizontal view of another preferred means of moving the plunger relative to the seal means, illustrating a series of support struts defined on the plunger in initial expanded position.
FIG. 9 is a view similar to that of FIG. 8 illustrating the operation and position of the support struts during movement of the plunger toward the collapsed position after reaching the expended position.
FIG. 10 is a view similar to that of FIGS. 8 and 9, illustrating the final collapsed position of the plunger resulting in the movement of the plunger and cutting of the seal element.
FIG. 11 is a horizontal sectional view of an alternate preferred embodiment of securing the plunger relative to the seal means.
FIG. 12 is a detailed horizontal sectional view of the area highlighted in FIG. 11.
FIG. 13 is a view similar to that shown in FIG. 11 showing yet another alternative preferred means for securing the plunger relative to the seal means.
FIG. 14 is a horizontal sectional view of still another alternative preferred embodiment for securing the plunger to the sealing means.
FIG. 15 is a view of still another alternative preferred embodiment shown in the initial expanded position.
FIG. 16 is a horizontal section view of the device depicted in FIG. 15, illustrating the sealing means in the fully collapsed position.
FIG. 17 is another illustration of still another preferred embodiment, showing the cutter element being defined at the distal end of the plunger.
FIG. 18 is a view similar to that of FIG. 15, but showing yet another alternative embodiment of providing the sealing means 600 in a single element, thereby eliminating the need for the housing member 602.
FIG. 19 is a view similar to that of FIG. 18 but showing the embodiment of FIG. 18 moved to the collapsed position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now, with first reference to FIG. 1, the syringe 10 of the present invention is shown with an outer elongated barrel element 100 interiorally receiving a plastic hollow plunger 200. The plastic hollow plunger is manufactured by known techniques for making such plastic components, but will be typically made through injection molding techniques of a plastic such as polypropylene.
Also, as shown in FIG. 1, the syringe device 10 of the present invention includes a hollow needle 300 having a pointed open end 301. An unextended portion of the needle 300 is securely engaged within a spring housing 30 with the needle 300 extending out of an open end 31 of the spring housing 30.
A cover 20 is slidably, but securely engaged around the spring housing 30 and has an inwardly circumferentially conically defined shoulder 21 which snugly engages a companion conically shaped shoulder 32C on the spring housing 30. As the cover 20 is moved toward the housing 100, it freely moves dorsally along the spring housing 30 until the portions 21 and 32C interface. Prior to interface, a circular groove 32B, which is indented around the exterior dorsal end of the spring housing 30, receives a companion abatement 32A around the interior diameter of the body 25 of the cover 20 to snap-secure the case 20 in place. This snap engagement may be overcome by hand manipulation of the guide 20 distally away from the housing 100.
The cover 20 has a closed end 22, extended radially around the exterior of the pointed open end 301 of the hollow needle 300. The cover, as shown, has a series of circumferentially extending wing member 23, 24 protruding outwardly from the body 25 of the cover 20 and formed as an integral unit or portion of body 25. Additionally, the body 25 has a radially outwardly extending ring 26 including a shoulder 27 for assisting in one-handed removal of the cover 20. The human operator may remove the cover 20 by hand or finger application to either the ring 26 or one or more of the wings 23, 24, or both the ring 26 and one or more of the wings 23, 24 to unsnap the engagement 32A/32B.
Continuing with reference to FIGS. 1 and 2, there is shown an opening 101a in the barrel through which the plunger 200 is introduced through the first end 101 to the expended position 202. If medication or other fluid 105 is pre-introduced into the syringe 10 and into a chamber 104 within the inside diameter wall 103 of the barrel 100, it will be appreciated that the plunger 200 will be in the expanded position 201 as shown in FIG. 2. In other words, the syringe 10 is designed such that a medicinal fluid 105 may be placed into the syringe 10 and the cap or cover 20 snugly secured around a second or distal end 102 of the barrel or housing 101 and the cover 20 thereafter removed for injection of the fluid 105 into the patient.
Alternatively, the syringe 10 may be provided and positioned, such as in FIG. 1, the cover 20 thereafter removed at or about the application site and just before injection of the fluid 105 is needed. Thereafter, the cover 20 is removed and the pointed open end 301 of the needle 300 may be introduced into an exterior container for the fluid 105 and the plunger moved to the expanded position 201 (FIG. 2) to draw the fluid 105 through the pointed open end 301 into the chamber 104 by vacuum caused by the movement of the plunger 200 from the expended position 202 as shown in FIG. 1 to the expanded position 201, as shown in FIG. 2.
The barrel 100 has immediate its second or distal end 102 a series of radially and circumferentially extending thread-like elements 106 which are inter-engaged with companion thread-like elements 33 disposed around the exterior of the spring housing 30. Accordingly, the spring housing 30, during manufacture of the syringe 10, may be merely hand or mechanically threaded to the barrel 100 to secure the barrel 100 and the spring housing 30 together.
A spring lock device 34 is also initially contained within the spring housing 30, but is disengageable therefrom to the position shown in FIG. 3.
As stated above, the plunger 200 is manufactured of a plastic material which enables a considerable amount of force to be hand-applied to the plunger 200 through the finger or thumb of a human operator upon the means for directing forward pressure upon the plunger, such as ring or plate-like surface 500 (FIGS. 1, 2, and 3). This force is transmitted through the plunger 200 for movement of the fluid 105 through the pointed open end 301 of the needle 300 and introduction into the patient, thereby fully expending fluid within the chamber 104, and, thereafter, enabling a cutting tip 700 to further advance.
When the sealing means 600 has been fully cut and the spring lock 34 has been disengageably secured in relationship with the spring housing 30 and the barrel 100, the plunger 200 is moved to the collapsed position shown in FIG. 3. This technique is described in somewhat more detail in U.S. Pat. No. 5,053,010 entitled "Safety Syringe With Retractable Needle" issued Oct. 1, 1991.
Also, as stated above, it has been found that the sealing means 600 does not provide as effective sealing between the exterior thereof and the inside diameter wall 103 of the barrel 100 if the sealing means 600 includes a sealing member 601 (as in FIGS. 5-19) which is made of a material having the same given hardness as that of the plastic hollow plunger 200. A softer and more elastomeric material can be utilized to provide such an effective sealing means 600.
To assure that the barrel 100 and the plunger 200 do not telescopically expand relative to one another after the syringe 10 has been moved from the position as shown in FIG. 2 to the position as shown in FIG. 3, and, further, to avoid the possible loss of the needle 300 and/or exposure of the pointed open end 301 resulting in inadvertent contact with the patient or other human, the syringe 10 is provided with a radially interiorally extending lock ring 106 (FIG. 2) or other locking means, such as a series of inwardly projecting fingers, extensions, or the like, which are emplaced and defined on the barrel 100 immediate the first or dorsal end 101 thereof. Cooperative locking doughnut, or tabs, 207 are placed radially around the exterior of the plunger 200 just below or away from the plate or surface 500.
As the syringe 10 is moved from the position as shown in FIG. 2 to the collapsed position 203 shown in FIG. 3, the locking tabs or ring will be placed into contact with a beveled lock ring surface 106a (FIG. 2), and when such contact is made between surface 106a of the ring 106 and tabs 207, slight resistance to further telescopically retracting movements between the barrel 100 and the plunger 200 will be felt by the human operator through his/her finger upon plate 500. Continued application of slightly increased pressure on plate 500 will cause the locking tabs 207 to slide over and below the lock ring 106, with the lock ring 106 expanding, just slightly, immediate to the first end of 101. When the locking tabs 207 pass inwardly below the lock ring 106, the lock ring 106 will flexibly move back into its initial position and, in fact, will radially inwardly retract, just slightly, due to contact upon a profile surface 207a defined on the plunger 200. Since the lock ring 106 now has its outer surface in contact with the surface 207a of the plunger 200, the barrel 100 and the plunger 200 are inter-engageably locked by the position of the lock ring 106 relative to outwardly extending locking tabs 207.
As shown in FIG. 4, the plunger 200 is positioned to the fully expended position 202 and the distal end of the plunger 204 is about to move to the collapsed position, allowing the cutter 700 to continue through the sealing means 600. This permits the spring lock 34 to become disengaged such that the biasing or spring means 400 now may be released, causing the force contained within the spring 400 when it is in its retracted position as shown in FIG. 1, to urge the spring lock 34 away from the spring lock housing 35. The spring 400 has an end 401 which is snuggly contained within the spring housing 30 by means of an arresting shoulder 32 which extends internally, with an open end 31 permitting the hollow needle 300 to extend thereout.
Now with reference to FIGS. 5 through 19, there are shown a number of alternate preferred means 800 for engaging the plunger 200 to the sealing means 600. For example, with first reference to FIGS. 5, 6 and 7, there is shown an engaging means 800 which is provided on the distal end of plunger 204. As shown, the engaging means 800 is defined by a series of radially extending support struts 802 which are members extending between the plunger 200 and the sealing means 600. The struts 802 can be made of the same material utilized to make the plunger 200 and/or the housing 602 for the sealing member 601. Each of the support struts 802 will have an external diameter 803 which is slightly less than the internal diameter 602a of the companion housing 602 of the sealing means 600. As pressure is applied to the plunger 600, the support struts 802 will be caused to be sheared, thus permitting the plunger 200 to provide means 801 for telescopically engaging the plunger 200 to the distal end 204 relative to the sealing means 600, and the plunger 200 will continue to move interiorally of the sealing means 600 to the collapsed position shown in FIG. 7. The number and size of the struts can be varied to achieve different levels of shear forces required to collapse the sealing means. For example, as shown in FIG. 4, this may be simply a very thin connecting ring, 610 of plastic material between the housing 602 and the end of the plunger 200.
Now referring to FIGS. 8, 9, 10, another alternative means for securing the end of the plunger 200 to the sealing means 600 is shown. With first reference to FIG. 8, the device is shown in expended position 201, with the distal end 204 of the plunger 200 providing either one or a series of vertically collapsible support pleats 206 having a series of vertically positioned horizontal pleat elements 205. As pressure is applied to the plate 500 of the plunger 200, the plunger will telescope relative to the barrel 100 and the pleats 206 will first be caused not to be able to sustain resistance to such amount of pressure and will, in turn, cause the collapsible pleat 205 members to collapse as the pleats 206 are flexed, as shown in FIG. 9, to the collapsed position 202 as shown in FIG. 10.
Of course, the horizontal pleats 206 can sustain the amount of pressure necessary to cause the plunger 200 to telescope retractedly relative to the barrel 100 to eject the medication or fluid 105 from the chamber 104 and, thus, close the chamber 104, i.e., the expended position, without deflecting the collapsible members 205. When all medication is ejected through the pointed open end 301 of the needle, and when the seal means 600 is moved to the abutting position as shown in FIG. 1, the resistance to further movement caused thereby will result in the struts 205 moving from the position as shown in FIG. 8 to the position as shown in 9 as increased pressure is applied to the plate 500 and transmitted through the plunger 200. This increased mechanical pressure will move the plunger 200 to the collapsed position 202 as shown in FIG. 10 when the plunger 200 has moved relative to the barrel 100 to cut through the seal means 600.
Now with respect to FIGS. 11 and 12, there is shown still another alternate preferred means 800 for engaging the plunger 200 to the sealing means 600 which uses a snap-fitting detent assembly comprising a ring 820 and a ring recess 810. As shown in the blowup FIG. 12, the plunger 200 is secured to the housing element 602 of the seal means 600 by means of a ring 820 received within a beveled shoulder 650 of the seal means 600. The bevel-shaped shoulder 650 snugly secures the ring 820 for affixation purposes. However, when sufficient pressure is applied through the plunger 200, the ring 820 will move along the shoulder 650 such that the ring 820 is caused to be flexed inwardly just slightly until it reaches the profile 902 carried on the member 602, at which time the ring 820 will be caused to radially expand, just slightly, into snug securing engagement relative to the profile 902 and thus permits continued movement of the plunger 200 from the expended position to the collapsed position to be accomplished.
Housing 602 is molded as a separate component and snapped onto the end of plunger 200. The distal end of plunger 200 has the annular ring 820 molded onto it. The interior of the housing 602 has a mating recess 810 whose shoulder 650 resists expansion and compression. However, the shoulder 650 resists compression of the ring component 820 and allows it to be overcome with a predetermined amount of force, thereby allowing the cutter 700 to advance.
Now with respect to FIG. 13, there is shown still another alternate preferred means 800 for engaging the plunger 200 to the sealing means 600, using either one or a series of adhesive spots 606. When the plunger reaches the expended position, hand pressure for continued forward movement of the plunger 200 will be resisted and further applied pressure will shear or break the spots 606 so that the plunger may thereafter move to the collapsed position. There are, of course, a number of adhesives which can be utilized, such as cyanoacrylate, Super-Glue™, Durabond™ or UV-15™, made by Masterbond.
Also, as shown in FIG. 13, the housing 602 has an internal diameter 603 which, at the dorsal end 605, is contourly beveled to provide a smooth radially and outwardly extending shoulder 606 for application of the adhesive and also to the outer surface of the plunger distal end 204. The distal end 204 of the plunger is first flexed somewhat inwardly to permit the shoulder configuration of the dorsal end 605 to come over, just slightly, the end 204, such that, in some circumstances, the use of the adhesive means 900 may be combined with slight mechanical inward bias between the sealing member housing 602 and the end 204 such that the sealing means 600 and the plunger 200 are engaged together by a combination of mechanical and chemical means. The amount of adhesive used, the extent to which it completely surrounds the housing 602, and the shape of the bead provided through application of the adhesive, all act to effect the amount of force required to move the plunger 200 relative to the sealing means 600. Of course, as the adhesive engagement between the members is broken, the plunger 204 will continue inwardly within the housing 602 to effect operation of the device 10, as shown in FIGS. 1, 2, and 3.
Now with respect to FIG. 14, there is shown yet another alternative embodiment, somewhat similar to FIG. 13. FIG. 14 shows housing 602 firmly attached to the distal end of plunger 200 by means of ultrasonic, heat staking, friction welding or any other means resulting in a similar weld, as is well known to those skilled in such arts. Each of these techniques can be used to create one or more rigid connections 902a and 902b between parts 602 and 200.
With respect to FIGS. 15 and 16, another alternative preferred means 800 for engaging the plunger 200 to the sealing means 600 is shown. As shown in FIG. 15, a projection 842 which may be continuous or collet-like outwardly extends from the tip of the end of the plunger 200 and into the sealing means 600 at receptacle 843. The shape of this projection resists pulling out of the sealing means 600. Further, under forward pressure the shape tends to expand the sealing means tighter against the barrel 100 to prevent leakage. Under sufficient pressure, however, the projection 842 can no longer resist movement of the sealing means 600, allowing it to collapse to the position shown in FIG. 16 and the profile 844 now receives the projection(s) 842 which are flexed outwardly after passage across the internal housing wall 640. It will be appreciated that a shoulder 620 is provided on the housing 602 and is substantially vertical (in the views of FIGS. 15 and 16) to the horizontally disposed plunger 200. this assists in enabling the plunger 200, securing means 800 and the sending means 600 to travel as a unit from the position shown in FIG. 1 to that shown in FIG. 2, during introduction of fluid 105.
Now, with reference to FIG. 17, yet another embodiment of the invention is illustrated in which the cutter 700 is an integral component of the plunger 200 and, in fact, is formed near the distal end of the plunger member 200.
The distance 850 defines the travel of the plunger 200 to the no-go end 651 of the housing 602 of the seal means 600. Travel of the plunger 200 this distance 850 is the distance from the expended position to the collapsed position in all embodiments shown in the Figs.
FIGS. 18 and 19 show yet another embodiment of the invention where the sealing means 600 is provided with the seal 601 extended and used without a separate housing 602. The seal element 601 still provides the groove 843 with the shoulder 620 for receipt of the protrusion 842. Some economical savings might be enjoyed if it is desired to use the construction as shown in FIGS. 18 and 19.
The invention also contemplates usage of a needle 700 with the cutting end as contoured such as 760 (FIG. 17). Alternatively, the cutting configuration 760 may provide that the end of the cutter 700 is dome-like or pyramid-like or any other variant to the form 760.
The invention includes the method of delivering fluid to a patient utilizing the device 10 of the present invention. When in the "ready" or expanded position of FIG. 2, after removal of the cover means 20 (FIG. 1), the method contemplates the use of the apparatus 10 which will include inter-engagement of the plunger 200 relative to the seal means 600 in one of the preferred embodiments. The needle is implanted into the patient by the operator either by application of hand or fingers around the exterior of the barrel 100 and/or application of forward pressure to the plate 500 by the operator. Force is applied one handedly to one end of the plunger 200 to coerce the fluid 105 from within the chamber 104 within the barrel 100 and into the patient through an arm, leg, or otherwise. The plunger is moved to the expended position shown in FIG. 2 and, thereafter, additional one handed force is applied to the plate or surface 500 at one end of the plunger 200 to further drive the plunger to the collapsed position (FIG. 3) so that the cutting tip 700 extends through the spring lock housing 30 to thereby release the biased needle 300 into the plunger 200. The plunger 200 then is locked relative to the barrel 100 by the inter-engagement of the locking tabs 207 relative to the lock ring 106 (FIG. 3).
Although the invention has been described in terms of specified embodiments which are set forth in detail, it should be understood that it is by illustration only and that the invention is not necessarily limited thereto, since other alternative embodiments and operating techniques will become apparent to those skilled in the art in view of the disclosure. Accordingly, modifications are contemplated which can be made without departing from the spirit of the described invention. | A non-reusable retractable safety syringe is provided which has a hollow plunger and a seal member carried thereon. The provision of the plunger and the seal relative to the barrel permits the plunger, with sufficient strength, to carry applied pressure through the device during injection of a medicinal or other fluid into a patient, and yet permit the seal disposed at one end of the plunger to have maximum sealing integrity between the plunger and a cylindrical barrel disposed around the exterior of the plunger, to abate leakage of the liquid in a chamber within the barrel, as the plunger is manipulated from an expanded position to an expended position and thereafter to a third, or collapsed position. Designs for securing the seal relative to the plunger are disclosed. The syringe may be used to insert and/or withdraw fluid relative to the patient. | 0 |
FIELD OF THE INVENTION
The present invention relates to devices for providing individual workpieces such as silicon wafers or flat panel displays with a pre-selected orientation relative to a treatment beam.
BACKGROUND OF THE INVENTION
The manufacture of semiconductors during the front end stages includes a number of process steps whereby a silicon wafer is presented to an incoming ion beam, plasma, molecular beam, or other irradiating elements. In some cases, the irradiating element is scanned across the surface of the silicon wafer to provide a uniform spatial irradiation and the time spent determines the doping level. In others, the wafer is moved across a stationary beam of irradiating elements. High current ion implanters with purely mechanically scanned workpiece holders are examples of systems that scan the wafers through a stationary beam and provide on average uniform spatial doping. Doping uniformity is servo-controlled using the measured doping rate to vary the speed and duration of one mechanical axis while the other is controlled at a constant speed. Doping level is controlled by adjusting the number of completed scan passes in the servocontrolled direction such that the total dose is equally divisible by the number of scan passes. This technique is well known to those knowledgeable in the art and needs no further explanation.
The semiconductor industry is now migrating to 300 mm wafer diameters that cause the vacuum chambers and extent of mechanical motion to increase beyond practical limits for two direction mechanical scan systems. Furthermore, the cost of a single 300 mm wafer is currently very expensive which makes it desirable to process wafers individually rather than in batches because of the cost and wafer handling risks. Finally, the recent requirement of increasing the wafer tilt angles from the current 7 degrees to as much as 60 degrees precludes the use of mechanically scanned batch systems due to the variation in implant angle and twist across the wafer.
SUMMARY OF THE INVENTION
The present invention provides high angle tilt ion implants for silicon wafers with fast servo-controlled mechanical scanning in one direction and fast magnetic scanning in the orthogonal direction. Some of the features of this invention are:
(1) a differentially pumped integral air bearing vacuum seal for linear motion in the Y direction for the mechanical scan structure;
(2) a differentially pumped integral air bearing vacuum seal for rotary motion about the X-axis;
(3) air bearings for supporting the mechanical scan structure, centering and supporting the rotary seal, and centering and supporting the Y-scan linear seal; and
(4) synchronous gating of the ion beam during transitions between implant states.
In other words, the ion beam is held off the wafer whenever a loss of beam is detected or other requirements dictate that the system go from an implant in progress to an implant hold state. This can occur while a flag Faraday is inserted into the beam path for set-up or tuning purposes.
For purposes of describing the geometry of the system, the mechanical scanning system uses Cartesian coordinates X, Y, and Z while the magnetic scanned beam uses Cartesian coordinates X', Y', and Z'. In all cases X and X' are identical. The ion beam is perpendicular to the X'Y' plane and is magnetically scanned in the X' direction.
In one aspect of the present invention, there are two movable bearing plates spaced from a fixed plate using gas bearings with an integral differentially pumped vacuum seal to prevent physical contact between seal surfaces on each of the plates. The combination gas bearing and vacuum seal for the outermost plate provides friction free movement in the Y direction. The combination gas bearing and vacuum seal for the inner plate provides friction free rotation about the X axis. The combination of the two moveable bearing plates provides tilting of a workpiece holder at any angle between 0 and 60 degrees for ion implanting in a silicon wafer and 90 degrees for horizontal wafer handling. This is accomplished by rotating the two moveable bearing plates about the X axis creating an angle between the Z & Z' and Y & Y' directions. The Z' direction is parallel with the incoming ion beam and Z is perpendicular to the surface of the workpiece holder. The tilting of the workpiece holder allows implants into the sides of deep trenches and gate structures located on the surface of the silicon wafer, a desirable feature for state of the art semiconductor manufacture. Horizontal wafer handling is a desirable feature in that it uses gravity to hold wafers while in motion obviating the need for edge clamping on the wafer that may result in damage to the wafer. Additional gas bearings center the rotating bearing plate about the X axis as well as prevent lateral motion of the outermost bearing plate along the Z direction.
In another aspect of the present invention, the ion beam intercepts each point on the surface of the workpiece (e.g., wafer) at the same distance along the Z' axis as the workpiece is reciprocated in the Y direction. This is accomplished using only three axes of controlled motion. If one assigns a unit vector to the wafer surface orientated with respect to the crystal lattice and another unit vector to the incoming ion beam, the relationship between these two vectors is constant as the wafer is reciprocated in front of the ion beam throughout the implantation process. Furthermore, the distance along the Z' axis to every point on the surface of the wafer as the wafer is reciprocated through the beam is the same such that each point on the wafer surface experiences exactly the same ion flux and trajectory. Thus enabling precise control over ion channeling through the crystal lattice during implantation leading to superior control over implant uniformity throughout the volume of the implanted surface.
In another aspect of the present invention, the magnetic scanner is used to hold the ion beam in the overscan region for a short duration while an upstream Faraday is inserted or retracted to prevent fine structure (i.e., non-uniformity) in the doping level across the wafer. To avoid non-uniformity in the doping, the ion beam is sampled when it is scanned off the edge of the wafer and both the magnetic and mechanical scanning controls are stopped if beam loss is detected. The implant is started in the same way, the beam is deflected off the wafer path before the Faraday is retracted and scanning starts precisely where it was interrupted. This method is also used to temporarily interrupt the implant for any reason deemed necessary.
In another aspect of the present invention, there is provided an apparatus having a vacuum chamber having a chamber wall, a workpiece holder disposed within the vacuum chamber and extending through the chamber wall, a reciprocating member receiving the workpiece holder, and a rotating member interposed between the reciprocating member and the chamber wall.
In yet another aspect of the present invention, there is provided a method for ion implantation of a workpiece, including the steps of generating an ion beam perpendicular to a first XY plane, tilting the workpiece to a second XY plane relative to the first XY plane, scanning the ion beam across the workpiece along the X axis of the first XY plane and translating the workpiece along the Y axis of the second XY plane with all points on a face of the workpiece being equidistance from the source of the ion beam.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic representation of an ion implantation device in accordance with the present invention.
FIGS. 2A-2D are detailed views of the translating and rotating seal assembly of the present invention.
FIGS. 3A-3C are detailed views of the rotating seal assembly.
FIG. 4 is a vacuum schematic.
FIG. 5 is a diagrammatic representation of a portion of the Faraday system in accordance with the present invention.
FIG. 6 is an illustration of the current integrator function.
FIG. 7 is a diagrammatic representation of the Faraday system in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention can be used to mechanically scan 200 or 300 mm silicon wafers through an ion beam at speeds sufficient to reduce wafer heating and charging effects. It is important to note that although the present invention is described herein with respect to ion implantation, the present apparatus can also be used for other scanning operations, such as for the treatment of flat panels for flat panel displays. The ion beam is either fanned (i.e., a large rectangular cross section) or scanned (i.e., a small beam swept back and forth to form a large rectangular scanned area) at high speeds (e.g., in the range of about 150 Hz) in a direction (e.g., the X direction) orthogonal to that of the mechanical scan direction (e.g., the Y direction). The term "scanning" as used herein encompasses either magnetic or electrostatic fanning and magnetic or electrostatic scanning. The mechanical scanning (i.e., reciprocating) in the Y direction moves the wafer back and forth at high speeds (e.g., in the range of about 0.5 to 1 Hz) through the ion beam at a speed that is proportional to the measured beam current. In this way, the doping level per mechanical scan pass is controlled and the total dose is proportional to the dose per scan pass times the number of scan passes. In order to achieve mechanical scanning within the vacuum chamber 24 at high speeds with frictionless operation for long wear life and no particle generation, the present invention uses a novel combination of a linear motion bearing with differentially pumped vacuum seal (for friction-free movement in the Y direction) mounted on a rotary motion bearing with differentially pumped vacuum seal (for friction-free rotation about the X axis) on the exterior of the vacuum chamber 24. The linear motion bearing has a shaft 11 with a workpiece holder 10 at the distal end which extends through each of the vacuum seals into the vacuum chamber 24. The shaft 11 and workpiece holder 10 are translated in the Y direction by reciprocating the bearing and seal member or plate 12. The shaft 11 and workpiece holder 10 are tilted, along with bearing and seal member 12, by rotating the bearing and seal assembly 17.
The novel combination of a linear motion bearing and seal member with a workpiece holder and shaft attached thereto mounted on a rotary motion bearing and seal member provides isocentric scanning of the workpiece using the least number (i.e., three) of axes of motion possible. Isocentric scanning means that every intersection point of the ion beam with the surface of the workpiece is the same distance from the collimator magnet 98 exit boundary and the angular orientation of the ion beam and the angular orientation of the workpiece remain constant during the implant. The only three axes of motion required are (1) magnetically scanning the ion beam back and forth in the X' direction, (2) tilting the workpiece 18 and linear motion bearing and seal member 12 about the X axis, and (3) reciprocating the workpiece 18 and linear motion bearing and seal member 12 along the tilted Y axis (i.e., reciprocating the workpiece 18 and linear motion bearing and seal plate 12 in the plane of the surface of the workpiece).
Referring to FIG. 1, the workpiece holder 10 is attached to a hollow shaft 11 connected to the linearly moveable bearing and seal member or plate 12. Bearing plate 12 reciprocates in the Y direction providing mechanical scanning of the workpiece (e.g., a silicon wafer) 18 through the parallel magnetically scanned ion beam 13. The ion beam 13 is directed along the Z' direction and magnetically scanned back and forth in the X' direction perpendicular to the X'Y' plane creating a parallel scanned ion beam 13. Hollow shaft 11 extends through bearing plate 12 and slot 32 (FIG. 3) in the raised portion 21 of wall of vacuum chamber 24 and rotating bearing assembly 17. Portion 21 is described herein as a raised portion of the vacuum chamber wall but it should be understood that the portion 21 need not be raised. Likewise, it should be understood that the portion 21 can be a fixed plate attached to the wall of the vacuum chamber.
The combination of the moveable bearing members 12 and 17 provides tilting of the workpiece holder 10 (see FIG. 5) at any angle between 0 and 60 degrees from vertical for ion implanting in a silicon wafer and between 0 and 90 degrees for wafer handling. Tilting is accomplished by rotating the moveable bearing members 12 and 17 about the X axis creating an angle between the Z & Z' and Y & Y' axes. The Z' direction is defined as being parallel with the incoming ion beam and Z is defined as being perpendicular to the surface of the workpiece holder 10. The tilting of the workpiece holder 10 allows implants into the sides of deep trenches and gate structures located on the surface of the silicon wafer. Horizontal wafer handling (i.e., tilting the workpiece holder 90 degrees from vertical) in accordance with the present invention uses gravity to hold the wafer on the workpiece holder while in motion obviating the need for edge clamping on the wafer that may result in damage to the wafer. Gas bearings 28 (FIG. 2B) on the exterior of vacuum chamber wall 21 center the rotating bearing and seal assembly 17 about the X axis. Gas bearings 30 mounted on rectangular bearing plate 19 prevent lateral motion of the bearing member 12 along the Z direction.
The bearing member or plate 12 (FIG. 1) is connected to a drive motor 14 controlled by a computer 15. The computer 15 in combination with a current integrator 73 monitors the ion flux arriving in a downstream Faraday 16. The velocity in the Y direction imparted to the bearing plate 12 by the motor 14 is varied in proportion to the ion flux measured by the control computer 15 so as to create uniform average flux density across the surface of the workpiece 18. With the laterally moveable bearing plate 12 connected to the rotating bearing member or assembly 17 by support arm 97 the intercept of the ion beam 13 with the workpiece 18 is maintained at a constant distance along the Z' axis as the workpiece 18 is translated back and forth through the ion beam 13 by the linear drive motor 14. The rotary motion of the rotating bearing assembly 17 is provided by a linear drive motor (not shown) and associated linkage (not shown) as known in the art.
Rotation of the bearing assembly 17 by 90 degrees from vertical about the X axis when the bearing plate 12 is in its uppermost position allows horizontal handling of the workpiece 18 during wafer load and unload from the wafer handler 99. The surface of the workpiece holder 10 may be rotated about its Z axis to any rotation angle between 0 and 360 degrees through a drive system (not shown) connected through the hollow shaft 11. This permits wafer flat or notch orientation prior to implantation and may be done while the workpiece holder 10 is in motion from the load position to the implant position eliminating time normally wasted for wafer flat orientation. The present invention uses a video camera and processing software for the purpose of locating the position and orientation of each wafer relative to the load/unload robot 99 and workpiece holder 10 while the handler is in motion. This allows precise loading of the wafer onto the workpiece holder 10 as well as correct flat or notch orientation. This video image may also be used to capture the part code or number scribed onto the wafer surface for material tracking purposes. Rotation about the Z axis of the surface of the workpiece holder is also an enabling function for implants into the sides of deep trenches and gate structures.
Referring to FIGS. 2A-3C, the details of the linear reciprocating bearing and seal plate 12 and the rotating bearing and seal assembly 17 are shown. Rotating bearing and seal assembly 17 is made up of bearing and seal plate 19 and a circular bearing and seal plate 20 attached on opposite sides of a center plate 31. The gas bearings will be described first. Bearing and seal plate 20 of seal assembly 17 is separated from wall portion 21 by a gas bearing formed by an array of gas nozzles 25 (FIG. 3C) located on the surface 59 of the bearing plate 20. A high pressure gas manifold 58 (FIG. 2D) is connected to each of the gas nozzles 25 to provide a steady supply of gas for the gas bearing. The pressure over surface 59 between the outer and inner gas nozzles 25 is maintained at a constant pressure by flow restrictors in the nozzles 25 and the spacing between the seal and bearing plate 20 and the wall portion 21. The wall portion 21, which is a circular seal plate, is fixed in position relative to the overall vacuum chamber 24. Wall portion 21 contains a set of air bearings 28 (FIG. 2B) that center the rotating seal assembly 17 about the center of the fixed seal plate 21 by applying a gas force directed in the radial direction against the side of the center plate 31. Bearing and seal plate 19 of seal assembly 17 is separated from bearing and seal plate 12 by a gas bearing formed by an array of gas nozzles 26 (FIGS. 2B and 3A) located on the surface 90 of the bearing plate 19. A high pressure gas manifold (not shown) supplies a steady supply of gas for the gas bearing. The pressure over surface 90 between the outer and inner gas nozzles 26 is maintained at a constant pressure by flow restrictors in the nozzles 26 and the spacing between the seal and bearing plate 19 and the seal and bearing plate 12. A set of gas bearings 30 attached to the bearing plate 19 prevent movement of the seal plate 12 in the Z direction by applying a gas force to the opposite sides of the seal plate 12.
Having described the gas bearings, the vacuum seals will now be described. Pumping grooves 37, 40 and 41 (FIGS. 3B and 3C) in the surface of the bearing and seal plate 20 form a differentially pumped vacuum seal between bearing and seal plate 20 and wall portion 21 of the vacuum chamber 24. Pumping grooves 33, 38 and 39 (FIGS. 3A and 3B) in the surface of the bearing and seal plate 19 form a differentially pumped vacuum seal between bearing and seal plate 19 and bearing and seal plate 12. Grooves 33, 38 and 39 have an oval shape to accommodate the rectangular shape of the reciprocating seal plate 12. The bearings and seals are non-contact with respect to each other and the reciprocating shaft 11 thus providing a friction-free, non-particle generating, high speed rotation and linear motion vacuum feed-through.
The balance of force on each of the elements of the vacuum seal assembly is as follows. Atmospheric pressure working against the vacuum inside the vacuum chamber 24 applies an external force which balanced against the air cushion created by the gas bearing between the bearing and seal plate 12 and the bearing and seal plate 19 creates a slight separation between the plate 12 and plate 19 while preventing movement in the X direction of the seal plate 12. The set of air bearings 30 located on opposite sides of the seal plate 12 and attached to the rotating seal assembly 17 apply equal forces in the positive Z and negative Z directions preventing contact and relative Z motion between the seal plate 12 and the bearing plate 19. In this way seal plate 12 is prevented from moving in either the X or Z direction but allowed frictionless translation in the Y direction. Atmospheric pressure working against the vacuum inside the vacuum chamber 24 also applies an external force which balanced against the air cushion created by the gas bearing between the bearing and seal plate 20 and the wall portion 21 creates a slight separation between the plate 20 and wall portion 21 while preventing contact and relative X motion between the wall portion 21 and the bearing and seal plate 20. The set of air bearings 28 attached to the wall portion 21 apply a uniform radial force against the center plate 31 preventing contact and relative radial motion between the seal assembly 17 and the wall portion plate 21. The wall portion 21, which is a seal plate, is attached to the vacuum chamber 24 fixing the position of the seal plate 21 which in turn fixes the position of the seal assembly 17 which in turn fixes the position of the seal plate 12 relative to the vacuum chamber 24. The rotating seal assembly 17 is constrained in X, Y and Z but allowed frictionless rotary motion about the X axis. The pressure inside the air bearing regions 59 and 90 is self-regulated to some fraction of the pressure inside the high pressure manifold. This self-regulation occurs because the gap between the bearing and seal plates is constrained only by the atmospheric pressure applied to the outside of the seal plates, thereby controlling the leak rate of air out of the bearing regions. By adjusting the pressure in the high pressure manifold, one can vary the gap between the seal and bearing plates. The gap between the seal and bearing plates is, preferably, 0.001 inches or less.
Since the gas bearing gap is very small, the gas flow rates required to produce the gas bearing are also very small (e.g., 1 to 4 cubic feet per minute). For proper spacing, the opposing seal and bearing plate surfaces must be very flat across their entire width. A technique known as "lapping" performed by Form Centerless Co. in St. Medfield, Mass. can be used to achieve the desired flatness which should be within 0.0003 inches of true flatness. To prevent damage to the seal and bearing plate surfaces if they were to come into contact, an anodized surface such as polytetrafluoroethylene-penetrated hardcoat anodizing for aluminum alloys sold under the tradename NITUFF available from Nimet Industries, Inc. in South Bend, Ind., nickel, or hard chrome can be applied to the surface of the seal surfaces and bearing plate.
Referring now to FIGS. 3 and 4, the differentially pumped vacuum seal system will now be described. An oval slot 32 extends through the plates 19, 20, and 31 in direct communication with the high vacuum region of the vacuum chamber 24. The slot 32 allows non-contact full translation of the workpiece holder 10 and shaft 11 in the Y direction. Adjacent to slot 32 is the oval pumping groove 33 (FIG. 3A) in the surface of the plate 19. Ports 36 extending through the center plate 31 connect groove 33 to circular groove 37 in the surface of the bearing plate 20. Oval grooves 38 and 39 are connected to circular grooves 40 and 41 through ports 42 and 43, respectively. Each pair of oval and circular grooves are connected through ports (not shown) to the differential pumping vacuum system shown in FIG. 4 as follows. Grooves 33 and 37 and ports 36 are connected to the third stage 34 of the differential pumping system and nearly isolated from the high vacuum region 52 and the second stage 53 of the differential pumping system by the seal surfaces 29 and 35 and 46 and 49, respectively. Grooves 38 and 40 and ports 42 are connected to second stage 53 of the differential pumping system and nearly isolated from the third stage 34 and the first stage 54 of the differential pumping system by the seal surfaces 46 and 49 and 47 and 50, respectively. Grooves 39 and 40 and ports 43 are connected to the first stage 54 of the differential pumping system and nearly isolated from the second stage 53 of the differential pumping system and atmosphere 55 by the seal surfaces 47 and 50 and 48 and 51, respectively. Grooves 56 and 57 in seal plates 19 and 20, respectively, located at a greater diameter than the other grooves are ported to the atmosphere side of the vacuum seal assembly to exhaust the air that escapes the inside perimeter of the air bearing assembly. Each set of grooves are described as "nearly" isolated because there is some movement of gas over the seal surfaces toward the vacuum region.
Referring now to FIG. 4, the vacuum schematic illustrates the differential pumping system which includes a high vacuum cryo-pump 60 to create a vacuum in the vicinity of the workpiece 18, a turbomolecular mechanical pump 61 to maintain the pressure in the third stage differential pumping region 34, a second turbomolecular pump 62 connected to the exhaust port 65 of the first turbomolecular pump 61 and to the second stage differential pumping region 53, a dry mechanical pump 63 connected to the exhaust port 66 of the second turbomolecular pump and to the first stage differential pumping region 54 with its outlet exhausted to atmosphere 55. The pressure in each of the successive differential pumping stages 54, 53 and 34, drops by roughly an order of magnitude from atmosphere at 55 to less than a millibar in the third stage 34. The conductance between the third stage 34 and the high vacuum region 52 is several orders of magnitude lower than the pumping speed of the high vacuum pump 60 reducing the pressure in the vicinity of the workpiece 18 to a level near the base pressure of the high vacuum pump 60.
As bearing and seal member 12 reciprocates along the Y axis, the two outermost ends 92 and 94 (FIGS. 1 and 2B) are extended beyond the ends of the seal plate 19 thus exposing the ends 92 and 94 to the atmosphere where the ends pick up moisture. As the end exposed to the atmosphere is translated to a position where it is exposed to the vacuum seal grooves, moisture from the seal member 12 is drawn into the vacuum region creating a load causing the vacuum pumps to work harder. Therefore, in a preferred embodiment, a dry gas (e.g., nitrogen) blanket is applied using a shield or bag to each of the ends 92 and 94 as they travel past the ends of the seal plate 19 to prevent them from picking up moisture.
As conventionally known in the prior art, the workpiece holder 10 has an electrostatic chuck for holding silicon wafers onto a ceramic coated platen surface, a plurality of gas cooling ports to feed gas to the region between the back of the wafer and the surface of the platen, a plurality of water cooling passages to cool the backside of the electrostatic chuck, a rotary bearing, a differentially pumped rotary shaft seal assembly, a plurality of wafer lifting pins, and a drive assembly used to rotate the surface of the workpiece holder 0 to 360 degrees about an axis perpendicular to the workpiece.
Magnetic scanning is conducted with the present invention such that the ion beam trajectory is maintained perpendicular to the X' Y' plane at all times. As described previously, two magnetic deflection systems 95 and 98 (FIG. 7) located one after the other along the beam flight path are used. Referring to FIGS. 5 and 7, the implantation control system will be described. A Faraday assembly 16 is mounted to a linear actuator 68 that provides motion of the Faraday 16 along the X' direction. The Faraday 16 is fitted with an aperture plate 69 positioned with its surface in the X'Y' plane. A thin slit aperture 70 is located through the aperture plate 69 with its long dimension oriented in the Y' direction. The Faraday 16 is moved by the linear actuator 68 such that the slit 70 may be positioned anywhere within the transverse range of the scanned beam 13 along the X' direction. The aperture plate 69 and its slit 70 are longer in the Y' direction than the Y' height of the beam 13. This allows for the beam 13 to be scanned across the surface of the aperture plate 69 admitting a fraction of the beam current into the Faraday cup 71 located behind the plate 69. The current-time profile of the Faraday signal may be transformed into a one-dimensional beam intensity-position profile using suitable arithmetic in a computer controlled measurement system as known by those of ordinary skill in the art. This enables correlation between magnetic scan amplitude and beam position in the X' direction.
In a preferred embodiment, there are two movable Faraday assemblies 16 and 72. Downstream Faraday 16 is located in the beam scanning plane next to the workpiece holder 10 and the Faraday 72 is located upstream. Both Faraday assemblies have the same freedom of motion allowing identical measurements of the ion beam 13 both upstream and downstream inside the vacuum chamber 24. The downstream Faraday 16 serves the dual purposes of beam setup and measuring and controlling implant dose. The upstream and downstream Faradays 16 and 72 are used to measure beam parallelism. Each of these Faradays is positioned in the beam path 13 at identical X' positions but with different Z' positions. Since the magnetic scan waveform (amplitude versus time) is repetitive, the amplitude versus beam position can be expressed in terms of the phase angle of the repeated wave form. The phase angle difference between measurements of beam position in the two Faradays 16 and 72 is used to calculate the deviation from parallel for the scanned rays of the ion beam 13. These phase angle measurements are made when the workpiece holder 10 is moved out of the beam path.
The Faraday cup 72 is electrically connected to the vacuum chamber 24 through an electrometer circuit (not shown) to measure the total ion beam charge entering the Faraday cup 96 through slit 70' in plate 69'. For each positive ion entering the field of the Faraday cup 72, a negative charge is induced on the surface of the cup. These charges combine to maintain net neutrality. The flow of negative charge into the cup from the electrometer is a measure of ion beam flux entering the cup. When the ion beam consists of singlely charged ions, the number of negative charges equals the number of positive ions entering the Faraday cup 72 through the slit 70'.
In another aspect of the present invention, the magnetic scanner is used to hold the ion beam 13 in an overscan region off of the workpiece holder 10 for a short duration while the flag Faraday 93 is inserted or retracted from in front of the ion beam to prevent fine structure (i.e., non-uniformity) in the doping level across the workpiece. To avoid non-uniformity in the doping, the ion beam 13 is sampled when it is scanned off the edge of the wafer with the present invention and both the magnetic and mechanical scanning controls are stopped if beam loss is detected. The magnetic scanner is capable of holding the ion beam off the edge of the wafer for approximately 200 milliseconds providing ample time to insert the flag Faraday 93 into the ion beam path. This method is also used to temporarily interrupt the implant for any reason deemed necessary. The implant state is started in a similar manner, the ion beam 13 is turned on before the flag Faraday 93 is retracted and scanning starts precisely where it was interrupted.
In other words, the ion beam is held off the wafer whenever a loss of beam is detected or other requirements dictate that the system go from an implant in progress to an implant hold state. This occurs within a few tens of milliseconds while a flag Faraday 93 is inserted into the beam path for set-up or tuning purposes. The process of starting an implant occurs in a similar way. First the scanning magnet is set to deflect the beam off of the wafer path while the flag Faraday 93 is retracted. Then, the scanning starts with the beam off the wafer to prevent structure (i.e., non-uniformity) in the doping of the implanted wafer.
The ion beam 13 is scanned at a constant velocity V x across both the Faraday cup 71 and the workpiece 18 such that the ion beam 13 moves completely off the workpiece 18 and past the slit 70 during ion implantation steps. The one dimensional dose D x is measured by integrating the flux of charge entering the Faraday cup 71. This one dimensional dose D x is simply the integral of the charge flux and is measured by the scan control computer 15. The mechanical scan velocity V y of the workpiece holder 10 in the Y direction is controlled by the scan control computer 15 in proportion to the one dimensional dose D x measured during each back and forth pass of the ion beam 13 across the Faraday cup 71 and workpiece 18. The dose D x multiplied by a constant K determines the total dose per unit area that the workpiece 18 receives in a single back and forth pass of the workpiece 18 through the scanned ion beam 13. The total dose per unit area received by the workpiece in a complete implant cycle is determined by the single pass dose times the number of passes N. Both the number of passes N and the constant K are predetermined such that after N passes the desired dose is received by the workpiece 18.
During beam setup, the workpiece holder 10 is moved in the Y direction to a location clear of the Faraday 16 to allow for X' motion of the Faraday 16 for purposes of measuring beam parallelism and scan uniformity. FIG. 6 illustrates the amplitude time wave form of the current integrator 73 (FIG. 1) associated with the scan control computer 15. The wave form results from the ion beam 13 being scanned across the Faraday slit 70. The current integrator 73 consists of a current-to-voltage converter section followed by an integrator section. The output wave form 74 of the current-to-voltage converter section is integrated to produce the integral wave form 75. The flat regions 76 and 78 of the integrator output represent the periods when no part of the ion beam 13 is entering the Faraday cup 71. The rising region 79 of the integrator output represents the period when the ion beam 13 passes over the Faraday slit 70 allowing a portion of the ion beam to enter the Faraday cup 71. The sharp negative slope 80 of the wave form 75 represents the integrator-reset function. A fast sampling A/D converter (not shown) is used to measure the amplitude of the integrator output during the periods 76, 79 and 78 to determine instrument offset, dark or stray current, and beam current reproduced by the current-to-voltage converter. Offset and dark current are determined by the slope of the amplitude during periods 76 and 78. Beam current is measured during the period 79. The slope of periods 76 and 78 are multiplied by the total integrator period 81 and then subtracted from the difference between the starting sample 82 and ending sample 83 to arrive at a corrected integral measurement. The time of the one-half height measurement 84 corresponds to the time when the beam is centered over the Faraday slit 70 which precisely defines the beam position in the X' direction. Each of the Faradays 16 and 72 are stepped across the X' positions and measure the beam arrival times 84 relative to the turn around points in the magnetic scan space X'. Although the Faradays 16 and 72 cover the same X' positions, they occupy separate but parallel X'Y' planes during these measurement steps.
A pulse integrator (not shown) in combination with a sampling A/D converter (not shown) and the small movable Faraday cups 16 and 72 measure beam profiles, magnetic scan linearity, beam parallelism, dose rate, and instrumentation offset. This information is used in combination to compensate for offset or dark current, scan non-linearity, variations in beam current versus X' position, and beam parallelism during set-up and during implant operations. The magnetic scan profile of magnet current versus time may be modified to produce a one-dimensional uniform doping profile across the target plane in the X' direction. The method of measuring dark current (which is all unwanted constant currents including instrumentation offset) is accomplished by sampling the slope of the integrator output as the beam passes across the Faraday aperture, including a period before and a period after its passage. The pulse integrator is enabled for a precisely fixed period of time and produces an analog output that is the time integral of the beam current pulse and any stray current not related to the ion beam. The stray current may include instrument offset current, leakage current in the Faraday, electron current from wafer charged neutralizers, ion current from the background plasma surrounding the ion beam, or any other source of constant current summed together and included in the integral measurement. The characteristic wave form of the integrator output, when sampling a pulse or current with no contributing offsets has two periods of time one before and one after passage of the pulse when the slope of the integrator output versus time is zero. When an offset current is simultaneously summed with the true beam current pulse, the slope before and after the passage of the beam pulse is constant and is easily measured using a fast sampling A/D convertor. Since the slope is constant and measurable, the product of the slope and the integrator time period can easily be subtracted from the integral measurement to arrive at the true integrated beam current pulse.
The method of measuring beam parallelism and scan uniformity utilizes the two separate Faradays 16 and 72 in combination with the integrator 73 to measure the X' position of the ion beam in two parallel X'Y' planes. Each Faraday 16 and 72 is positioned using a stepper motor drive 91 in combination with a linear drive mechanism 68 and 68' to provide accurate and repeatable X' position in small discrete 0.001 inch steps (FIG. 5). Faraday 16 is positioned such that its slit 70 is located in the implant plane while the Faraday 72 is positioned upstream. The width of the beam 13 is larger than the slit width, however, this is of no consequence since the integrator output yields the total integrated current once the beam passes over the slits 70 and 70'. This integrated current is the one dimensional dose D x at the X' position of each of the Faradays. Varying the X' position of each of the Faradays enables measurement of D x at discrete locations across the magnetic scan space. The output wave form, after it has been corrected for offset or dark current will have three pieces of information critical for this control algorithm. The ending amplitude of the integrator output less the beginning amplitude is the integral of the beam current. The time at which the half amplitude of the integrator output is reached corresponds to the time when the beam center is coincident with the center of the Faraday slit. These two measurements, D x and X'(t), provide the basis for calibrating parallelism and scan or dose uniformity of the system. Since the magnetic scan wave form is repetitive, the ion beam retraces the same space across the X' direction in a continuous manner with each successive magnetic scan pass. It follows that by positioning a Faraday at discrete locations in the X' scan space one can measure X' and D x at each of these locations. Assigning X' i and X' j to locations corresponding to the upstream and downstream Faradays 16 and 72, respectively, with the i and j positions being identical in X' but not Z', then the angular deviation in the ion beam trajectory from the Z' direction is the arc-tangent of Δx/Δz. Where Δx is equal to X' i minus X' j . The collimator magnet 98 is adjusted under software control to assure a minimum angular variation across the scan space.
The next step is to calibrate the scanner magnet 95. It is a requirement for uniform dose control in the implant plane that the discrete values of D xj be equal. The scan velocity V x must be constant to achieve a uniform dose when the beam current is constant. The scanner 95 is simply calibrated by measuring values of X j versus B j and finding a scan wave form that satisfies the requirement for constant scan velocity. Once the wave form is defined that produces a constant velocity V x , the doses checked, D x against X is measured and variations are used to recalculate a function to modify the scan velocity. The final result is a polynomial in time T that defines the magnetic scan wave form that includes corrections for beam intensity variation as well as non-linearity in the scanner magnet 95.
It will be appreciated by those of ordinary skill in the art that the invention can be embodied in other specific forms without departing from the spirit or essential character thereof. 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 rather than the foregoing description, and all changes which come within the meaning and range of equivalents thereof are intended to be embraced therein. | An apparatus used to control a workpiece inside a vacuum chamber. The workpiece is supported on a workpiece holder in the vacuum chamber. The workpiece is isolated from the atmosphere outside of the vacuum chamber by differentially pumped vacuum seals and an integral air bearing support. The differentially pumped vacuum seals and integral air bearing support allow for multiple independent motions to be transmitted to the workpiece supported by the workpiece holder. The workpiece holder motions provided are (1) rotation about the X axis, (2) translation back and forth along the Y direction of an X-Y plane on the surface of the workpiece holder, and (3) rotation of the workpiece in the X-Y plane about its Z axis. Concentric seals, oval for the translation motion and circular for the rotational motion, are differentially pumped through common ports to provide successively decreasing pressure and gas flow in order to reduce the gas load into the vacuum vessel to a negligible rate. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2007-295962, filed on Nov. 14, 2007, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a nonvolatile semiconductor memory device and method of manufacturing the same.
2. Description of the Related Art
Electrically erasable programmable nonvolatile memories include a flash memory as well known in the art, which comprises a memory cell array of NAND-connected or NOR-connected memory cells having a floating gate structure. A ferroelectric memory is also known as a nonvolatile fast random access memory.
On the other hand, technologies of pattering memory cells much finer include a resistance variable memory, which uses a variable resistor in a memory cell as proposed. Known examples of the variable resistor include a phase change memory element that varies the resistance in accordance with the variation in crystal/amorphous states of a chalcogenide compound; an MRAM element that uses a variation in resistance due to the tunnel magneto-resistance effect; a polymer ferroelectric RAM (PFRAM) memory element including resistors formed of a conductive polymer; and a ReRAM element that causes a variation in resistance on electrical pulse application (Patent Document 1: JP 2006-344349A, paragraph 0021).
The resistance variable memory may configure a memory cell with a serial circuit of a Schottky diode and a resistance variable element in place of the transistor. Accordingly, it can be stacked easier and three-dimensionally structured to achieve much higher integration advantageously (Patent Document 2: JP 2005-522045A).
SUMMARY OF THE INVENTION
In an aspect the present invention provides a nonvolatile semiconductor memory device, comprising: a plurality of first lines; a plurality of second lines crossing the plurality of first lines; a plurality of memory cells each connected at an intersection of the first and second lines between both lines and including a variable resistor operative to store information in accordance with a variation in resistance; and a protection film covering the side of the variable resistor to suppress migration of cations at the side of the variable resistor.
In another aspect the present invention provides a nonvolatile semiconductor memory device, comprising: a plurality of first lines; a plurality of second lines crossing the plurality of first lines; a plurality of memory cells each connected at an intersection of the first and second lines between both lines and including a variable resistor operative to store information in accordance with a variation in resistance; and a protection film covering the side of the variable resistor to suppress at least one of reduction reaction, oxidation reaction and migration of anions at the side of the variable resistor.
In another aspect the present invention provides a method of manufacturing nonvolatile semiconductor memory devices, comprising: sequentially depositing a first metal layer, a barrier metal layer, anon-ohmic element layer, a first electrode layer, a variable resistor layer, and a second electrode layer in a memory cell array to form a stacked structure; forming a trench to separate the stacked structure; forming a protection film on the side of the trench; burying an insulator film in the trench covered with the protection film and planarizing the insulator film; and forming a second metal layer in the memory cell array over the insulator film, the protection film and the second electrode layer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a nonvolatile memory according to a first embodiment of the present invention.
FIG. 2 is a perspective view of part of a memory cell array in the nonvolatile memory according to the same embodiment.
FIG. 3 is a cross-sectional view of one memory cell taken along I-I′ line and seen from the direction of the arrow in FIG. 2 .
FIG. 4 is a schematic cross-sectional view showing a variable resistor example in the same embodiment.
FIG. 5 is a schematic cross-sectional view showing another variable resistor example in the same embodiment.
FIG. 6 is a schematic cross-sectional view showing a non-ohmic element example in the same embodiment.
FIG. 7 is a perspective view of part of a memory cell array according to another embodiment of the present invention.
FIG. 8 is a cross-sectional view of one memory cell taken along II-II′ line and seen from the direction of the arrow in FIG. 7 .
FIG. 9 is a cross-sectional view of the nonvolatile memory according to the same embodiment.
FIG. 10A is a flowchart showing a step of manufacturing the nonvolatile memory according to the same embodiment.
FIG. 10B is a flowchart showing a step of manufacturing the nonvolatile memory according to the same embodiment.
FIG. 10C is a flowchart showing a step of manufacturing the nonvolatile memory according to the same embodiment.
FIG. 11 is a perspective view showing a step of forming the upper layer portion in the nonvolatile memory according to the same embodiment in order of step.
FIG. 12 is a perspective view showing a step of forming the upper layer portion in the nonvolatile memory according to the same embodiment in order of step.
FIG. 13 is a perspective view showing a step of forming the upper layer portion in the nonvolatile memory according to the same embodiment in order of step.
FIG. 14 is a perspective view showing a step of forming the upper layer portion in the nonvolatile memory according to the same embodiment in order of step.
FIG. 15 is a perspective view showing a step of forming the upper layer portion in the nonvolatile memory according to the same embodiment in order of step.
FIG. 16 is a perspective view showing a step of forming the upper layer portion in the nonvolatile memory according to the same embodiment in order of step.
FIG. 17 is a perspective view showing a step of forming the upper layer portion in the nonvolatile memory according to the same embodiment in order of step.
FIG. 18A is a flowchart showing a step of manufacturing a nonvolatile memory according to a third embodiment of the present invention.
FIG. 18B is a flowchart showing a step of manufacturing the nonvolatile memory according to the third embodiment of the present invention.
FIG. 19 is a cross-sectional view of a nonvolatile memory according to a fifth embodiment of the present invention.
FIG. 20A is a flowchart showing a step of manufacturing a nonvolatile memory according to the third embodiment of the present invention.
FIG. 20B is a flowchart showing a step of manufacturing the nonvolatile memory according to the third embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
The embodiments of the invention will now be described with reference to the drawings.
First Embodiment
Entire Configuration
FIG. 1 is a block diagram of a nonvolatile memory according to a first embodiment of the present invention.
The nonvolatile memory comprises a memory cell array 1 of memory cells arranged in matrix, each memory cell including a later-described ReRAM (variable resistor). A column control circuit 2 is provided on a position adjacent to the memory cell array 1 in the bit line BL direction. It controls the bit line BL in the memory cell array 1 to erase data from the memory cell, write data in the memory cell, and read data out of the memory cell. A row control circuit 3 is provided on a position adjacent to the memory cell array 1 in the word line WL direction. It selects the word line WL in the memory cell array 1 and applies voltages required to erase data from the memory cell, write data in the memory cell, and read data out of the memory cell.
A data I/O buffer 4 is connected to an external host, not shown, via an I/O line to receive write data, receive erase instructions, provide read data, and receive address data and command data. The data I/O buffer 4 sends received write data to the column control circuit 2 and receives read-out data from the column control circuit 2 and provides it to external. An address fed from external to the data I/O buffer 4 is sent via an address register 5 to the column control circuit 2 and the row control circuit 3 . A command fed from the host to the data I/O buffer 4 is sent to a command interface 6 . The command interface 6 receives an external control signal from the host and decides whether the data fed to the data I/O buffer 4 is write data, a command or an address. If it is a command, then the command interface 6 transfers it as a received command signal to a state machine 7 . The state machine 7 manages the entire nonvolatile memory to receive commands from the host to execute read, write, erase, and execute data I/O management. The external host can also receive status information managed by the state machine 7 and decides the operation result. The status information is also utilized in control of write and erase.
The state machine 7 controls the pulse generator 9 . Under this control, the pulse generator 9 is allowed to provide a pulse of any voltage at any timing. The pulse formed herein can be transferred to any line selected by the column control circuit 2 and the row control circuit 3 .
Peripheral circuit elements other than the memory cell array 1 can be formed in a Si substrate immediately beneath the memory cell array 1 formed in a wiring layer. Thus, the chip area of the nonvolatile memory can be made almost equal to the area of the memory cell array 1 .
[Memory Cell Array and Peripheral Circuits]
FIG. 2 is a perspective view of part of the memory cell array 1 , and FIG. 3 is a cross-sectional view of one memory cell taken along I-I′ line and seen in the direction of the arrow in FIG. 2 .
There are plural first lines or word lines WL 0 -WL 2 disposed in parallel, which cross plural second lines orbit lines BL 0 -BL 2 disposed in parallel. A memory cell MC is arranged at each intersection of both lines as sandwiched therebetween. Desirably, the first and second lines are composed of heat-resistive low-resistance material such as W, WSi, NiSi, CoSi.
The memory cell MC comprises a serial connection circuit of a variable resistor VR and a non-ohmic element NO as shown in FIG. 3 .
The variable resistor VR can vary the resistance through current, heat, or chemical energy on voltage application. Arranged on an upper and a lower surface thereof are electrodes EL 1 , EL 2 serving as a barrier metal layer and an adhesive layer. Material of the electrodes may include Pt, Au, Ag, TiAlN, SrRuO, Ru, RuN, Ir, Co, Ti, TiN, TaN, LaNiO, Al, PtIrOx, PtRhOx, Rh/TaAlN. A metal film capable of achieving uniform orientation may also be interposed. A buffer layer, a barrier metal layer and an adhesive layer may further be interposed.
The variable resistor VR may include one that comprises a composite compound containing cations of a transition element and varies the resistance through migration of cations (ReRAM).
FIGS. 4 and 5 show examples of the variable resistor. The variable resistor VR shown in FIG. 4 includes a recording layer 12 arranged between electrode layers 11 , 13 . The recording layer 12 is composed of a composite compound containing at least two types of cation elements. At least one of the cation elements is a transition element having the d-orbit incompletely filled with electrons, and the shortest distance between adjacent cation elements is 0.32 nm or lower. Specifically, it is represented by a chemical formula A x M y X z (A and M are different elements) and may be formed of material having a crystal structure such as a spinel structure (AM 2 O 4 ), an ilmenite structure (AMO 3 ), a delafossite structure (AMO 2 ), a LiMoN 2 structure (AMN 2 ), a wolframite structure (AMO 4 ), an olivine structure (A 2 MO 4 ), a hollandite structure (A x MO 2 ), a ramsdellite structure (A x MO 2 ), and a perovskite structure (AMO 3 ).
In the example of FIG. 4 , A comprises Zn, M comprises Mn, and X comprises O. In the recording layer 12 , a small white circle represents a diffused ion (Zn), a large white circle represents an anion (O), and a small black circle represents a transition element ion (Mn). The initial state of the recording layer 12 is the high-resistance state. When the electrode layer 11 is kept at a fixed potential and a negative voltage is applied to the electrode layer 13 , part of diffused ions in the recording layer 12 migrate toward the electrode layer 13 to reduce diffused ions in the recording layer 12 relative to anions. The diffused ions arrived at the electrode layer 13 accept electrons from the electrode layer 13 and precipitate as a metal, thereby forming a metal layer 14 . Inside the recording layer 12 , anions become excessive and consequently increase the valence of the transition element ion in the recording layer 12 . As a result, the carrier injection brings the recording layer 12 into electron conduction and thus completes setting. On data reading, a current may be allowed to flow, of which value is very small so that the material configuring the recording layer 12 causes no resistance variation. The programmed state (low-resistance state) may be reset to the initial state (high-resistance state) by supplying a large current flow in the recording layer 12 for a sufficient time, which causes Joule heating to facilitate the oxidation reduction reaction in the recording layer 12 . Application of an electric field in the opposite direction from that at the time of setting may also allow resetting.
In the example of FIG. 5 , a recording layer 15 sandwiched between the electrode layers 11 , 13 is formed of two layers: a first compound layer 15 a and a second compound layer 15 b . The first compound layer 15 a is arranged on the side close to the electrode layer 11 and represented by a chemical formula A x M1 y X1 z . The second compound layer 15 b is arranged on the side close to the electrode layer 13 and has gap sites capable of accommodating cation elements from the first compound layer 15 a.
In the example of FIG. 5 , A comprises Mg, M1 comprises Mn, and X1 comprises O in the first compound layer 15 a . The second compound layer 15 b contains Ti shown with black circles as transition element ions. In the first compound layer 15 a , a small white circle represents a diffused ion (Mg), a large white circle represents an anion (O), and a double circle represents a transition element ion (Mn). The first compound layer 15 a and the second compound layer 15 b may be stacked in multiple layers such as two or more layers.
In such the variable resistor VR, potentials are given to the electrode layers 11 , 13 so that the first compound layer 15 a serves as an anode and the second compound layer 15 b serves as a cathode to cause a potential gradient in the recording layer 15 . In this case, part of diffused ions in the first compound layer 15 a migrate through the crystal and enter the second compound layer 15 b on the cathode side. The crystal of the second compound layer 15 b includes gap sites capable of accommodating diffused ions. Accordingly, the diffused ions moved from the first compound layer 15 a are trapped in the gap sites. Therefore, the valence of the transition element ion in the first compound layer 15 a increases while the valence of the transition element ion in the second compound layer 15 b decreases. In the initial state, the first and second compound layers 15 a , 15 b may be in the high-resistance state. In such the case, migration of part of diffused ions in the first compound layer 15 a therefrom into the second compound layer 15 b generates conduction carriers in the crystals of the first and second compounds, and thus both have electric conduction. The programmed state (low-resistance state) may be reset to the erased state (high-resistance state) by supplying a large current flow in the recording layer 15 for a sufficient time for Joule heating to facilitate the oxidation reduction reaction in the recording layer 15 , like in the preceding example. Application of an electric field in the opposite direction from that at the time of setting may also allow reset.
The non-ohmic element NO may include various diodes such as (a) a Schottky diode, (b) a PN-junction diode, (a) a PIN diode and may have (d) a MIM (Metal-Insulator-Metal) structure, and (e) a SIS (Silicon-Insulator-Silicon) structure as shown in FIG. 6 . In this case, electrodes EL 2 , EL 3 forming a barrier metal layer and an adhesive layer may be interposed. If a diode is used, from the property thereof, it can perform the unipolar operation. In the case of the MIM structure or SIS structure, it can perform the bipolar operation. The non-ohmic element NO and the variable resistor VR may be arranged in the opposite up/down relation from FIG. 3 . Alternatively, the non-ohmic element NO may have the up/down-inverted polarity.
Plural such memory structures described above may be stacked to form a three-dimensional structure as shown in FIG. 7 . FIG. 8 is a cross-sectional view showing an II-II′ section in FIG. 7 . The shown example relates to a memory cell array of a 4-layer structure having cell array layers MA 0 -MA 3 . A word line WL 0 j is shared by an upper and a lower memory cells MC 0 , MC 1 . A bit line BL 1 i is shared by an upper and a lower memory cells MC 1 , MC 2 . A word line WL 1 j is shared by an upper and a lower memory cells MC 2 , MC 3 . In place of the line/cell/line/cell repetition, an interlayer insulator may be interposed as a line/cell/line/interlayer-insulator/line/cell/line between cell array layers.
The memory cell array 1 may be divided into MATs of several memory cell groups. The column control circuit 2 and the row control circuit 3 described above may be provided on a MAT-basis, a sector-basis, or a cell array layer MA-basis or shared by them. Alternatively, they may be shared by plural bit lines BL to reduce the area.
FIG. 9 is a cross-sectional view of the nonvolatile memory including the above-described memory structure in one stage. In this example, it is described that the first line is the bit line BL and the second line is the word line WL. This relation is opposite to that between the bit line BL and the word line WL as described in FIG. 2 but not related to the essence of the present embodiment. There is provided a silicon substrate 21 with a well 22 formed therein, on which an impurity-diffused layer 23 and a gate electrode 24 of a transistor contained in a peripheral circuit are formed, on which a first interlayer insulator 25 is deposited. The first interlayer insulator 25 includes a via-hole 26 appropriately formed therethrough to the surface of the silicon substrate 21 . On the first interlayer insulator 25 , a first metal 27 is formed of a low-resistance metal such as W to form the first line or bit line BL in the memory cell array. In an upper layer above the first metal 27 , a barrier metal 28 is formed. In a lower layer below the first metal 27 , a barrier metal may be formed. These barrier metals may be formed of both or one of Ti and TiN. Above the barrier metal 28 , a non-ohmic element 29 such as a diode is formed. On the non-ohmic element 29 , a first electrode 30 , a variable resistor 31 and a second electrode 32 are formed in this order, thereby configuring a memory cell MC including the barrier metal 28 through the second electrode 32 . A barrier metal may be interposed beneath the first electrode 30 and above the second electrode 32 . A barrier metal, and an adhesive layer or the like may be interposed below the second electrode 32 and on the first electrode 30 . The side of the memory cell MC is covered with a protection film 33 serving as an ion migration suppressing film. A second interlayer insulator 34 and a third interlayer insulator 35 are buried between the memory cell MC and an adjacent memory cell MC (the second interlayer insulator 34 is not shown in FIG. 9 ). On the memory cells MC in the memory cell array, a second metal 36 is formed to configure a second line or word line WL extending in the direction perpendicular to the bit line BL. A fourth interlayer insulator 37 and a metal wiring layer 38 are formed thereon to complete the variable resistance memory or nonvolatile memory. A multi-layered structure may be realized by stacking the barrier metal 28 through the second electrode 32 and forming the protection film 33 and the second and third interlayer insulators 34 , 35 between the memory cells MC, repeatedly by the number of layers required.
FIGS. 10A-10C show process flows associated with the above-described volatile memory. First, a FEOL (Front End of Line) process for forming transistors and so forth to form necessary peripheral circuits is executed (S 1 ), and then the first interlayer insulator 25 is deposited thereon (S 2 ). The via-hole 26 is formed as well in this step.
Subsequently, the upper layer portion above the first metal 27 is formed.
FIGS. 11-17 are perspective views showing steps of forming the upper layer portion in order of step. Referring to FIGS. 11-17 appropriately, processes of forming the upper layer portion are described.
Once the first interlayer insulator 25 and the via-hole 26 are formed as described above, deposition thereon of a layer 27 a turned into the first metal 27 in the memory cell array (S 3 ), formation of a layer 28 a turned into the barrier metal 28 (S 4 ), deposition of a layer 29 a turned into the non-ohmic element 29 (S 5 ), deposition of a layer 30 a turned into the first electrode 30 , deposition of a layer 31 a turned into the variable resistor 31 (S 7 ), and deposition of a layer 32 a turned into the second electrode 32 (S 8 ) are executed sequentially. Through the above steps, the stacked structure of the upper layer portion shown in FIG. 11 can be formed.
Examples of the layer 31 a turned into the variable resistor 31 include binary metal oxides such as NiO, TiO, WO and tertiary metal oxides such as ZnMnO, MgMnO. In the case of the binary metal oxide, oxidation increases Rset (the resistance at the time of set) and reduction decreases Rset. Therefore, oxidation/reduction of the metal oxide can optimize Rset. Oxidation of the side of the variable resistor material makes it possible to avoid further oxidation to achieve stabilized Rset. The oxidation of the side also makes it difficult to vary the resistance of the variable resistor and can exert the data retention improving effect.
As shown in FIG. 10B , in the step of depositing the layer 31 a turned into the variable resistor 31 (S 7 ), the gaseous atmosphere can be changed to vary Rset. Post-annealing in the Ar atmosphere (S 11 ) after the step of depositing the layer 32 a turned into the second electrode 32 (S 8 ) may exert such the effect as exerted by reduction, which can adjust Rset. It also exerts the film quality improving effect such as crystallization. At this time, the temperature and the gaseous atmosphere can be changed. Thereafter, as shown in FIG. 12 , trenches 41 are formed along the bit line BL to separate the stacked structure into pieces. For the purpose, a first etching is executed with L/S at the minimum pitch (S 12 ). In this case, the side of the variable resistor 31 facing the trench 41 is exposed and accordingly a first oxide film is formed as the protection film 33 (S 13 ) through oxidation such as ISSG (In-Situ Steam Generation), RTA (Rapid Thermal Annealing), and HTO (High-Temperature Oxide) with the temperature unchanged. Thus, a protection film 33 a is formed of an oxide film as shown in FIG. 13 .
Next, the second interlayer insulator 34 is buried in the trench 41 covered with the protection film 33 a (S 14 ). For the second interlayer insulator 34 , a suitable material has excellent insulation, a low capacity and an excellent burial property. Subsequently, a process of CMP or the like is applied in planarization to remove extra portions from the second interlayer insulator 34 and the protection film 33 a and expose the upper electrode 32 (S 14 ). A cross-sectional view after the planarization is shown in FIG. 14 . If a hard mask is used in this case, an etching or the like therefor is required.
A layer 36 a turned into the second metal 36 is stacked over the planarized portion after CMP (S 16 ). The state after this step is shown in FIG. 15 .
Thereafter, a second etching (S 17 ) is executed with L/S in the direction crossing the first etching (S 12 ), thereby forming trenches 42 along the word line WL orthogonal to the bit line BL as shown in FIG. 16 . At the same time, the memory cells MC separated in pillar shapes are formed at cross-points of the bit lines BL and the wordlines WL in a self-aligned manner. Thus, the side of the variable resistor 31 facing the trench 42 is exposed and accordingly a second oxide film is formed as the protection film 33 (S 18 ). Subsequently, the third interlayer insulator is buried (S 19 ) and then the third interlayer insulator is planarized (S 20 ), thereby forming the memory array layer of the cross-point type as shown in FIG. 17 .
Thus, through stacking flat films and patterning them twice with orthogonal L/S, such the cross-point cells can be formed in a self-aligned manner without any misalignment.
The above stacked-structure may be formed repeatedly to form a memory cell array of the multi-layered cross-point type (S 21 ). In this case, repetition of the steps of and after depositing the barrier metal layer 28 (S 4 ) can realized a memory cell array in which an upper layer and a lower layer share a line in the memory cell array. Alternatively, repetition of the steps of and after forming the first interlayer insulator 25 (S 2 ) can realized a memory cell array in which an upper layer and a lower layer share no line in the memory cell array.
Thereafter, the metal wiring layer 38 is formed (S 22 ) to complete the nonvolatile semiconductor memory device of the present embodiment.
In the present embodiment, the protection film 33 serving as the ion migration suppressing film is an oxide. Specific examples of the oxide may include oxides of chromium (Cr), tungsten (W), vanadium (V), niobium (Nb), tantalum (Ta), titanium (Ti), zirconium (Zr), hafnium (Hf), scandium (Sc), yttrium (Y), thorium (Tr), manganese (Mn), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi) or rare earth elements including lanthanum (La) through lutetium (Lu). Aluminum oxide (Al 2 O 3 ), copper oxide (CuO), and silicon oxide (SiO 2 ) may also be formed.
Examples of the composite material include barium titanate (BaTiO 3 ), strontium titanate (SrTiO 3 ), as well as calcium titanate (CaTiO 3 ), potassium niobate (KNbO 3 ), bismuth iron oxide (BiFeO 3 ), lithium niobate (LiNbO 3 ), sodium vanadate (Na 3 VO 4 ), iron vanadate (FeVO 3 ), vanadium titanate (TiVO 3 ), vanadium chromate (CrVO 3 ), nickel vanadate (NiVO 3 ), magnesium vanadate (MgVO 3 ), calcium vanadate (CaVO 3 ), lanthanum vanadate (LaVO 3 ), molybdenum vanadate (VMoO 5 ), molybdenum vanadate (V 2 MoO 8 ), lithium vanadate (LiV 2 O 5 ), magnesium silicate (Mg 2 SiO 4 ), magnesium silicate (MgSiO 3 ), zirconium titanate (ZrTiO 4 ), strontium titanate (SrTiO 3 ), lead magnesate (PbMgO 3 ), lead niobate (PbNbO 3 ), barium borate (BaB 2 O 4 ), lanthanum chromate (LaCrO 3 ), lithium titanate (LiTi 2 O 4 ), lanthanum cuprate (LaCuO 4 ), zinc titanate (ZnTiO 3 ), and calcium tungstate (CaWO 4 ). These can be used to form thin films and are accordingly usable as protection films.
Among those, aluminum oxide (Al 2 O 3 ), silicon oxide (SiO 2 ), barium titanate (BaTiO 3 ), strontium titanate (SrTiO 3 ), calcium titanate (CaTiO 3 ), potassium niobate (KNbO 3 ), bismuth iron oxide (BiFeO 3 ), lithium niobate (LiNbO 3 ), sodium vanadate (Na 3 VO 4 ), magnesium silicate (MgSiO 3 ), zirconium titanate (ZrTiO 4 ), strontium titanate (SrTiO 3 ), barium borate (BaB 2 O 4 ), and zinc titanate (ZnTiO 3 ) are suitable for protection films because of extremely higher insulation thereof.
In addition, iron vanadate (FeVO 3 ), vanadium chromate (CrVO 3 ), lanthanum vanadate (LaVO 3 ), molybdenum vanadate (V 2 MoO 8 ), lead magnesate (PbMgO 3 ), lanthanum chromate (LaCrO 3 ), and calcium tungstate (CaWO 4 ) have relatively nice insulation.
The oxidation/reduction of the binary metal oxide as above and the thin film formation of the protection film make it possible to optimize Rset, reduce the side leakage current in the metal oxide, and improve the data retention.
Second Embodiment
In the above first embodiment the variable resistor including the binary metal oxide is described. In contrast, in the present embodiment an example using a variable resistor including a tertiary or higher metal oxide is described. An excessively oxidized tertiary or higher metal oxide such as ZnMnO and MgMnO increases O and elevates Rset. An excessively reduced one may also be considered to decrease O and elevate Rset. A variation in the amount of other metal ions may change Rset because the type of bond of metal ions to oxygen ions causes a conductor or an insulator correspondingly. Thus, the tertiary or higher metal oxide requires a protection film serving as the ion migration suppressing film to achieve optimization of O ions and metal ions and the composition thereof unchanged.
In the present embodiment, after the process flow of steps S 1 -S 6 in FIG. 10A is executed like in the first embodiment, the temperature and the gaseous atmosphere are changed at deposition of the layer turned into the variable resistor (S 7 ). As a result, the composition including plural types of metal ions and oxygen ions can be changed, thereby changing Rset. Then, the step of depositing the layer turned into the variable resistor (S 7 ) and the deposition of the layer turned into the second electrode (SB) are executed. Thereafter, post-annealing of FIG. 10B in Ar atmosphere or the like (S 11 ) may exert such the effect as exerted by reduction, which can adjust Rset. It also exerts the film quality improving effect such as crystallization. At this time, the temperature and the gaseous atmosphere can be changed. Thereafter, a first etching is executed (S 12 ) to expose the variable resistor material. Accordingly, a first oxide film is formed (S 13 ) like in the first embodiment through oxidation such as ISSG, RTA, and HTO.
In the present embodiment, the protection film 33 serving as the ion migration suppressing film is an oxide. Specific examples of the oxide may include oxides of chromium (Cr), tungsten (W), vanadium (V), niobium (Nb), tantalum (Ta), titanium (Ti), zirconium (Zr), hafnium (Hf), scandium (SC), yttrium (Y), thorium (Tr), manganese (Mn), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi) or rare earth elements including lanthanum (La) through lutetium (Lu). Aluminum oxide (Al 2 O 3 ), copper oxide (CuO), and silicon oxide (SiO 2 ) may also be formed.
Examples of the composite material include barium titanate (BaTiO 3 ), strontium titanate (SrTiO 3 ), as well as calcium titanate (CaTiO 3 ), potassium niobate (KNbO 3 ), bismuth iron oxide (BiFeO 3 ), lithium niobate (LiNbO 3 ), sodium vanadate (Na 3 VO 4 ), iron vanadate (FeVO 3 ), vanadium titanate (TiVO 3 ), vanadium chromate (CrVO 3 ), nickel vanadate (NiVO 3 ), magnesium vanadate (MgVO 3 ), calcium vanadate (CaVO 3 ), lanthanum vanadate (LaVO 3 ), molybdenum vanadate (VMoO 5 ), molybdenum vanadate (V 2 MoO 8 ), lithium vanadate (LiV 2 O 5 ), magnesium silicate (Mg 2 SiO 4 ), magnesium silicate (MgSiO 3 ), zirconium titanate (ZrTiO 4 ), strontium titanate (SrTiO 3 ), lead magnesate (PbMgO 3 ), lead niobate (PbNbO 3 ), barium borate (BaB 2 O 4 ), lanthanum chromate (LaCrO 3 ), lithium titanate (LiTi 2 O 4 ), lanthanum cuprate (LaCuO 4 ), zinc titanate (ZnTiO 3 ), and calcium tungstate (CaWO 4 ). These can be used to form thin films and are accordingly usable as protection films.
Among those, aluminum oxide (Al 2 O 3 ), silicon oxide (SiO 2 ), barium titanate (BaTiO 3 ), strontium titanate (SrTiO 3 ), calcium titanate (CaTiO 3 ), potassium niobate (KNbO 3 ), bismuth iron oxide (BiFeO 3 ), lithium niobate (LiNbO 3 ), sodium vanadate (Na 3 VO 4 ), magnesium silicate (MgSiO 3 ), zirconium titanate (ZrTiO 4 ), strontium titanate (SrTiO 3 ), barium borate (BaB 2 O 4 ), and zinc titanate (ZnTiO 3 ) are suitable for protection films because of extremely higher insulation thereof.
In addition, iron vanadate (FeVO 3 ), vanadium chromate (CrVO 3 ), lanthanum vanadate (LaVO 3 ), molybdenum vanadate (V 2 MoO 8 ), lead magnesate (PbMgO 3 ), lanthanum chromate (LaCrO 3 ), and calcium tungstate (CaWO 4 ) have relatively nice insulation.
The oxidation/reduction of the tertiary or higher metal oxide as above and the thin film formation of the protection film make it possible to optimize Rset, reduce the side leakage current in the metal oxide, and improve the data retention.
Third Embodiment
The above-described first embodiment uses an oxide as the protection film 33 serving as the ion migration suppressing film. In contrast, a third embodiment uses a nitride as the protection film 33 for a binary metal oxide. Nitriding the side of the variable resistor material makes it possible to avoid further oxidation of the metal oxide to achieve stabilized Rset. Nitriding the side also makes it difficult to vary the resistance of the variable resistor and can improve the data retention.
A process flow in this case is shown in FIGS. 18A and 18B . Different from FIGS. 10B and 10C , a step of forming a first nitride (S 31 ) is inserted in place of the first oxide formation (S 13 ) after the first etching (S 12 ). In addition, a step of forming a second nitride (S 32 ) is inserted in place of the second oxide formation (S 18 ) after the second etching (S 17 ).
In the present embodiment, the protection film 33 serving as the ion migration suppressing film is a nitride. Specifically, titanium nitride (TiN), gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si 3 N 4 ), magnesium nitride (MgN), molybdenum nitride (MoN), calcium nitride (CaN), niobium nitride (NbN), tantalum nitride (TaN), vanadium nitride (VN), zinc nitride (ZnN), zirconium nitride (ZrN), iron nitride (FeN), copper nitride (CuN), barium nitride (BaN), lanthanum nitride (LaN), chromium nitride (CrN), yttrium nitride (YN), lithium nitride (LiN), titanium nitride (TiN), and composite nitrides thereof are applicable. In addition, oxynitrides, for example, saialons in IA, IIA, IIIB groups, such as barium saialon (BaSiAlON), calcium saialon (CaSiAlON), cerium saialon (CeSiAlON), lithium saialon (LiSiAlON), magnesium saialon (MgSiAlON), scandium saialon (ScSiAlON), yttrium saialon (YSiAlON), erbium saialon (ErSiAlON) and neodymium saialon (NdSiAlON), or multinary saialons are also applicable. Further, lanthanum nitrosilicate (LaSiON), lanthanum europium nitrosilicate (LaEuSi 2 O 2 N 3 ) and silicon oxynitride (SiON 3 ) are also applicable.
Among those, gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si 3 N 4 ), magnesium nitride (MgN), lanthanum nitride (LaN), chromium nitride (CrN), yttrium nitride (YN), barium saialon (BaSiAlON), lanthanum nitrosilicate (LaSiON), lanthanum europium nitrosilicate (LaEuSi 2 O 2 N 3 ) and silicon oxynitride (SiON 3 ) are suitable for protection films because of extremely higher insulation thereof.
In addition, molybdenum nitride (MoN), calcium nitride (CaN), niobium nitride (NbN), vanadium nitride (VN), zinc nitride (ZnN), zirconium nitride (ZrN), iron nitride (FeN), copper nitride (CuN), barium nitride (BaN), and lithium nitride (LiN) exhibit excellent insulation abilities.
The thin film formation of the nitride as the protection film for the binary metal oxide as above makes it possible to optimize Rset, reduce the side leakage current in the metal oxide, and improve the data retention. In addition, the nitride is a material that can cut hydrogen and accordingly it is effective to prevent reduction.
Fourth Embodiment
In the above third embodiment the variable resistor including the binary metal oxide is described. In contrast, in the present embodiment an example using a variable resistor including a tertiary or higher metal oxide is described. An excessively oxidized tertiary or higher metal oxide such as ZnMnO and MgMnO increases O and elevates Rset. An excessively reduced one may also be considered to decrease O and elevate Rset. A variation in the amount of other metal ions may change Rset because the type of bond of metal ions to oxygen ions causes a conductor or an insulator correspondingly. Thus, the tertiary or higher metal oxide requires a protection film serving as the ion migration suppressing film to achieve optimization of O ions and metal ions and the composition thereof unchanged.
In the present embodiment, after the process flow of steps S 1 -S 6 in FIG. 10A is executed like in the third embodiment, the temperature and the gaseous atmosphere are changed at deposition of the layer turned into the variable resistor (S 7 ). As a result, the composition including plural types of metal ions and oxygen ions can be changed, thereby changing Rset. Then, the step of depositing the layer turned into the variable resistor (S 7 ) and the deposition of the layer turned into the second electrode (S 8 ) are executed. Thereafter, post-annealing of FIG. 18A in Ar atmosphere or the like (S 11 ) may exert such the effect as exerted by reduction, which can adjust Rset. It also exerts the film quality improving effect such as crystallization. At this time, the temperature and the gaseous atmosphere can be changed. Thereafter, a first etching is executed (S 12 ) to expose the variable resistor material. Accordingly, a first oxide film is formed (S 13 ) like in the third embodiment.
In the present embodiment, the protection film 33 serving as the ion migration suppressing film is a nitride. Specifically, titanium nitride (TiN), gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si 3 N 4 ), magnesium nitride (MgN), molybdenum nitride (MoN), calcium nitride (CaN), niobium nitride (NbN), tantalum nitride (TaN), vanadium nitride (VN), zinc nitride (ZnN), zirconium nitride (ZrN), iron nitride (FeN), copper nitride (CuN), barium nitride (BaN), lanthanum nitride (LaN), chromium nitride (CrN), yttrium nitride (YN), lithium nitride (LiN), titanium nitride (TiN), and composite nitrides thereof are applicable. In addition, oxynitrides, for example, saialons in IA, IIA, IIIB groups, such as barium saialon (BaSiAlON), calcium saialon (CaSiAlON), cerium saialon (CeSiAlON), lithium saialon (LiSiAlON), magnesium saialon (MgSiAlON), scandium saialon (ScSiAlON), yttrium saialon (YSiAlON), erbium saialon (ErSiAlON) and neodymium saialon (NdSiAlON), or multinary saialons are also applicable. Further, lanthanum nitrosilicate (LaSiON), lanthanum europium nitrosilicate (LaEuSi 2 O 2 N 3 ) and silicon oxynitride (SiON 3 ) are also applicable.
Among those, gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si 3 N 4 ), magnesium nitride (MgN), lanthanum nitride (LaN), chromium nitride (CrN), yttrium nitride (YN), barium saialon (BaSiAlON), lanthanum nitrosilicate (LaSiON), lanthanum europium nitrosilicate (LaEuSi 2 O 2 N 3 ) and silicon oxynitride (SiON 3 ) are suitable for protection films because of extremely higher insulation thereof.
In addition, molybdenum nitride (MoN), calcium nitride (CaN), niobium nitride (NbN), vanadiut nitride (VN), zinc nitride (ZnN), zirconium nitride (ZrN), iron nitride (FeN), copper nitride (CuN), barium nitride (BaN), and lithium nitride (LiN) exhibit excellent insulation abilities.
The thin film formation of the nitride for the tertiary or higher metal oxide as above makes it possible to optimize Rset, reduce the side leakage current in the metal oxide, and improve the data retention. In addition, the nitride is a material that can cut hydrogen and accordingly it is effective to prevent reduction.
Fifth Embodiment
The protection film serving as the ion migration suppressing film is formed of a single thin film of oxide or nitride in the above-described embodiments though the protection film may also be formed of plural thin films in a multi-layered structure. FIG. 19 shows an example of protection films 33 , 43 formed in a two-layered structure. Formation of plural thin films such as ON, NO, ONO, or ONONO in this way can form a much better protection film. Thus, band engineering in thin films can prevent electrons from entering from external and further stabilize the metal oxide. The formation of thin films as the protection film for the binary metal oxide or the tertiary or higher metal oxide in this way makes it possible to optimize Rset, reduce the side leakage current in the metal oxide, and improve the data retention.
Sixth Embodiment
The protection film 33 serving as the ion migration suppressing film is formed through oxidation or nitriding in the first through fifth embodiments though the protection film may be formed through a deposition process for either the binary metal oxide or the tertiary or higher metal oxide. A process flow in this case is shown in FIGS. 20A and 20B . Similar to other embodiments, after post-annealing the variable resistor (S 11 ), the first etching (S 12 ) is executed to expose the variable resistor material and a first protection film is deposited (S 41 ) with the temperature unchanged. Thus, the layer 33 a turned into the protection film can be deposited as shown in FIG. 13 . In addition, after the second etching (S 17 ), as shown in FIG. 20B , a second protection film is deposited (S 42 ) through the same process as above.
In this case, oxides (SiO 2 ), nitrides, SiN, SiON, Al 2 O 3 , low-permittivity insulators SiOF (fluorine-added silicon oxide), SiOC (carbon-added silicon oxide), organic polymeric materials may also be used. Further, oxides of chromium (Cr), tungsten (W), vanadium (V), niobium (Nb), tantalum (Ta), titanium (Ti), zirconium (Zr), hafnium (Hf), scandium (Sc), yttrium (Y), thorium (Tr), manganese (Mn), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi) or rare earth elements including lanthanum (La) through lutetium (Lu) may also be deposited. In addition, aluminum oxide (Al 2 O 3 ), copper oxide (CuO), and silicon oxide (SiO 2 ) may also be deposited.
As the composite material, barium titanate (BaTiO 3 ), strontium titanate (SrTiO 3 ), as well as calcium titanate (CaTiO 3 ), potassium niobate (KNbO 3 ), bismuth iron oxide (BiFeO 3 ), lithium niobate (LiNbO 3 ), sodium vanadate (Na 3 VO 4 ), iron vanadate (FeVO 3 ), vanadium titanate (TiVO 3 ), vanadium chromate (CrVO 3 ), nickel vanadate (NiVO 3 ), magnesium vanadate (MgVO 3 ), calcium vanadate (CaVO 3 ), lanthanum vanadate (LaVO 3 ), molybdenum vanadate (VMoO 5 ), molybdenum vanadate (V 2 MoO 8 ), lithium vanadate (LiV 2 O 5 ), magnesium silicate (Mg 2 SiO 4 ), magnesium silicate (MgSiO 3 ), zirconium titanate (ZrTiO 4 ), strontium titanate (SrTiO 3 ), lead magnesate (PbMgO 3 ), lead niobate (PbNbO 3 ), barium borate (BaB 2 O 4 ), lanthanum chromate (LaCrO 3 ), lithium titanate (LiTi 2 O 4 ), lanthanum cuprate (LaCuO 4 ), zinc titanate (ZnTiO 3 ), and calcium tungstate (CaWO 4 ) may be deposited.
As the nitride to be deposited, titanium nitride (TiN), gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), boron nitride (BN), silicon nitride (SiN), magnesium nitride (MgN), molybdenum nitride (MoN), calcium nitride (CaN), niobium nitride (NbN), tantalum nitride (TaN), vanadium nitride (VN), zinc nitride (ZnN), zirconium nitride (ZrN), iron nitride (FeN), copper nitride (CuN), barium nitride (BaN), lanthanum nitride (LaN), chromium nitride (CrN), yttrium nitride (YN), lithium nitride (LiN), titanium nitride (TiN), and composite nitrides thereof are applicable. In addition, oxynitrides, for example, saialons in IA, IIA, IIIB groups, such as barium saialon (BaSiAlON), calcium saialon (CaSiAlON), cerium saialon (CeSiAlON), lithium saialon (LiSiAlON), magnesium saialon (MgSiAlON), scandium saialon (ScSiAlON), yttrium saialon (YSiAlON), erbium saialon (ErSiAlON) and neodymium saialon (NdSiAlON), or multinary saialons are also applicable. Further, lanthanum nitrosilicate (LaSiON), lanthanum europium nitrosilicate (LaEuSi 2 O 2 N 3 ) and silicon oxynitride (SiON 3 ) are also applicable.
An available method of forming thin uniform oxide or nitride films as the first and second protection films may include ALD (Atomic Layer Deposition). The deposition of the protection films for the binary metal oxide and the tertiary or higher metal oxide as above makes it possible to optimize Rset, reduce the side leakage current in the metal oxide, and improve the data retention. In addition, the use of the nitride as the protection film is effective to prevent reduction because the nitride is a material that can cut hydrogen.
Seventh Embodiment
In the above embodiments the oxide or nitride is formed or deposited as the protection film. In contrast, in the present embodiment a material having a covalent bond is used as the protection film. This material can be used to form the protection film for either the binary metal oxide or the tertiary or higher metal oxide. Namely, the protection film plays a role in preventing oxygen ions and other metal ions from being accepted/released. In a word, a film may be formed preferably to prevent ions from migrating easily. With the use of the material having a covalent bond as the protection film, the covalent bond prevents the protection film itself from deteriorating, eliminates the migration path of ions, and prevents the metal film from deteriorating. For example, SiO 2 , diamond, carbon, and DLC (Diamond like Carbon) may be used as such the protection film.
The deposition of the protection film having a covalent bond for either the binary metal oxide or the tertiary or higher metal oxide as above makes it possible to optimize Rset, reduce the side leakage current in the metal oxide, and improve the data retention.
Eighth Embodiment
In the above embodiments the oxide or nitride is formed or deposited as the protection film, or the material having a covalent bond is used. In contrast, in the present embodiment a material having a higher valence of ion is used as the protection film. This material can be used to form the protection film for either the binary metal oxide or the tertiary or higher metal oxide. Namely, the protection film plays a role in preventing oxygen ions and other metal ions from being accepted/released. In a word, a film may be formed preferably to prevent ions from migrating easily. With the use of the material having a higher valence of ion as the protection film, the higher valence of ion prevents the protection film itself from allowing ions to migrate easily, eliminates the migration path of ions, and prevents the metal film from allowing ions to migrate and deteriorating. For example, Al 2 O 3 , and AlN may be used as such the protection film.
The deposition of the protection film having a higher valence of ion for either the binary metal oxide or the tertiary or higher metal oxide as above makes it possible to optimize Rset, reduce the side leakage current in the metal oxide, and improve the data retention.
Ninth Embodiment
In the above embodiments, after the thin film turned into the protection film is formed on the side of the variable resistor formed through the first and second etchings, the second and third interlayer insulators 34 , 35 are buried in the trenches 41 , 42 . In contrast, the second and third interlayer insulators 34 , 35 themselves may be used to serve as the protection film for the metal oxide.
In the present embodiment, the material, the film formation method, the film formation temperature, the atmosphere and so forth may be changed appropriately for film formation.
As the protection film, oxides (SiO 2 ), nitrides, SiN, SiON, Al 2 O 3 can be used, and low-permittivity insulators such as SiOF (fluorine-added silicon oxide) and SiOC (carbon-added silicon oxide), and organic polymeric materials may also be used. Further, oxides of chromium (Cr), tungsten (W), vanadium (V), niobium (Nb), tantalum (Ta), titanium (Ti), zirconium (Zr), hafnium (Hf), scandium (Sc), yttrium (Y), thorium (Tr), manganese (Mn), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), aluminum (Al), gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb), bismuth (Bi) or rare earth elements including lanthanum (La) through lutetium (Lu) may also be exemplified. In addition, aluminum oxide (Al 2 O 3 ), copper oxide (CuO), and silicon oxide (SiO 2 ) may also be formed.
As the composite material, barium titanate (BaTiO 3 ), strontium titanate (SrTiO 3 ), as well as calcium titanate (CaTiO 3 ), potassium niobate (KNbO 3 ), bismuth iron oxide (BiFeO 3 ), lithium niobate (LiNbO 3 ), sodium vanadate (Na 3 VO 4 ), iron vanadate (FeVO 3 ), vanadium titanate (TiVO 3 ), vanadium chromate (CrVO 3 ), nickel vanadate (NiVO 3 ), magnesium vanadate (MgVO 3 ), calcium vanadate (CaVO 3 ), lanthanum vanadate (LaVO 3 ), molybdenum vanadate (VMoO 5 ), molybdenum vanadate (V 2 MoO 8 ), lithium vanadate (LiV 2 O 5 ), magnesium silicate (MgZSiO 4 ), magnesium silicate (MgSiO 3 ), zirconium titanate (ZrTiO 4 ), strontium titanate (SrTiO 3 ), lead magnesate (PbMgO 3 ), lead niobate (PbNbO 3 ), barium borate (BaB 2 O 4 ), lanthanum chromate (LaCrO 3 ), lithium titanate (LiTi 2 O 4 ), lanthanum cuprate (LaCuO 4 ), zinc titanate (ZnTiO 3 ), and calcium tungstate (CaWO 4 ) may be formed.
In this case, TiN, gallium nitride (GaN), indium nitride (InN), aluminum nitride (AlN), boron nitride (BN), silicon nitride (SiN), magnesium nitride (MgN), molybdenum nitride (MoN), calcium nitride (CaN), niobium nitride (NibN), tantalum nitride (TaN), vanadium nitride (VN), zinc nitride (ZnN), zirconium nitride (ZrN), iron nitride (FeN), copper nitride (CuN), barium nitride (BaN), lanthanum nitride (LaN), chromium nitride (CrN), yttrium nitride (YN), lithium nitride (LiN), titanium nitride (TiN), and composite nitrides thereof are applicable. In addition, oxynitrides, for example, saialons in IA, IIA, IIIB groups, such as barium saialon (BaSiAlON), calcium saialon (CaSiAlON), cerium saialon (CeSiAlON), lithium saialon (LiSiAlON), magnesium saialon (MgSiAlON), scandium saialon (ScSiAlON), yttrium saialon (YSiAlON), erbium saialon (ErSiAlON) and neodymium saialon (NdSiAlON), or multinary saialons are also applicable. Further, lanthanum nitrosilicate (LaSiON), lanthanum europium nitrosilicate (LaEuSi 2 O 2 N 3 ) and silicon oxynitride (SiON 3 ) may be formed as interlayer insulators.
The use of the interlayer insulator as the protection film for the binary metal oxide and the tertiary or higher metal oxide as above makes it possible to optimize Rset, reduce the side leakage current in the metal oxide, and improve the data retention. In addition, the use of the nitride as the protection film is effective to prevent reduction because the nitride is a material that can cut hydrogen. | A nonvolatile semiconductor memory device includes a plurality of first lines; a plurality of second lines crossing the plurality of first lines; a plurality of memory cells each connected at an intersection of the first and second lines between both lines and including a variable resistor operative to store information in accordance with a variation in resistance; and a protection film covering the side of the variable resistor to suppress migration of cations at the side of the variable resistor. | 7 |
BACKGROUND OF THE INVENTION
This invention relates to the treatment of and the prevention of vaginal infections and the prevention of transmission of sexually transmitted diseases. The methods of this invention may be used to kill or inactivate virus, bacteria, chlamydia, rickettsia, mycoplasma and other potentially pathogenic microorganisms in humans and other mammals.
The following abbreviations used in the following disclosure are defined as follows:
______________________________________Povidone Povidone USP and equivalent products. Povidone has a molecular weight of above about 30 kd, the average molecular weight being about 40 kd typically. Povidone is polyvinyl pyrrolidone of the type generally available from GAF and BASF.Povidone Povidone complexed with iodine. Povidone iodineiodine typically comprises about 5 weight percent of iodine, plus about 10 weight percent iodide.LMW Polyvinyl pyrrolidone that has an average molecularPovidone weight of about 15,000 kd, typically 15,000 to 25,000 kd.______________________________________
Povidone-iodine is a widely used commercial product. Povidone-iodine, abbreviated here as povidone iodine is a complex of molecular iodine with polyvinyl pyrrolidone. Povidone iodine complexes of the type under consideration have been described in the literature and are marketed by The Purdue-Frederick Co. When percent concentrations are referred to in connection with povidone iodine, the percentage refers to the percent of povidone iodine by weight, based upon the weight of the solution or material to which the povidone iodine is added. Thus, a 1 weight percent ( w /o) solution of povidone iodine indicates that enough povidone iodine has been dissolved to result in a concentration of 1 w /o povidone iodine. In most instances, povidone iodine is added as a solution, e.g. 10% solution in water, pH about 1.5, but it can be added as a powder or otherwise. Povidone iodine powder contains approximately 85% povidone, 10% I and 5% iodide. A 10% solution of this powder contains 1% free, available iodine. (Gershenfeld, Am. J. Surgery 94, 938 (1957)).
Many and diverse diseases are transmitted sexually. Among the more common sexually transmitted diseases are condylomata acuminata (venereal warts), gonorrhea, syphilis, herpes simplex, granuloma venereum, chancroid, granuloma inguinale, non-gonococcal urethritis, acute pelvic inflammatory disease, vaginitis, and anorectal disease, and, of increasing concern, AIDS. Commonly sexually transmitted disease-causing organisms include Neisseria gonorrhoeae, Chlamydia trachomatis, Papillomavirus, Ureaplasma urealyticum, Mycoplasma hominis, Trichomonas vaginalis and Candida species.
Condylomata acuminata (venereal warts) is a sexually transmitted disease which has increased markedly in both adults and children during the past 15 years. The human papilloma virus is notoriously difficult to treat and often requires multiple office visits utilizing a variety of treatment modalities. Venereal warts are an ancient disease, but the relationship between certain human papillomavirus serotypes and genital neoplasia is just being recognized. Women are at higher risk for development of neoplasia from the infection and are more likely to be reinfected, because a male partner's lesions may be invisible without application of acetic acid or examination of a urethral smear. Other factors that favor progression to cancer are young age at first exposure, multiplicity of exposures, and immunosuppression.
Nonoxynol-9, a detergent that is widely used as a spermicide, has limited antibiotic activity; however, it does not kill or inactivate papillomavirus, the causative organism for venereal warts.
Vaginitis is a wide-spread disease which may be transmitted sexually or through other means. Vaginitis is a manifestation of a local infection by T. vaginalis, Candida, or Gardnerella vaginalis or other organisms. This invention has application to the treatment of vaginal diseases whether sexually transmitted or acquired through other contacts.
Herpesviruses, of which CMV is a member, represent a very large group of viruses which are responsible for, or involved in, cold sores, shingles, a venereal disease, mononucleosis, eye infections, birth defects and probably several cancers. Three subfamilies are of particular importance. The alpha subfamily includes HSV 1 (herpes simplex virus 1 ) which causes cold sores, fever blisters, eye and brain infections, HSV 2 (herpes simplex virus 2) which cause genital ulceration, and HSV 3 (HSV varicella zoster) which causes chicken pox, shingles and brain infections. The beta subfamily includes HSV 5, the principal member of which is CMV discussed above. The gamma subfamily includes HSV 4 (Epstein-Barr) which cause infectious mononucleosis and is involved in Burkitt's lymphoma and nasopharyngeal carcinoma.
The use of elemental iodine as an antiseptic dates back to about 1839. It is used today for various medicinal purposes. The combination of iodine with various solubilizing polymers led to a class of new compositions known as iodophors, which dominate the market once satisfied by simple alcoholic or aqueous iodine solutions. The iodine complexes with either nonionic surfactants, eg, polyethylene glycol mono(nonylphenyl)ether, or poly(vinylpyrrolidone) (povidone). The complexes function by rapidly liberating free iodine in water solutions. They exhibit good activity against bacteria, molds, yeasts, protozoa, and many viruses; indeed, of all antiseptic preparations suitable for direct use on humans and animals and upon tissues, only povidone iodine is capable of killing all classes of pathogens: gram-positive and gram-negative bacteria, mycobacteria, fungi, yeasts, viruses and protozoa. Most bacteria are killed within 15 to 30 seconds of contact. These iodophors are generally nontoxic, nonirritating to the skin and nonirritating upon short term application to membranes, non-sensitizing, and noncorrosive to most metals (except silver and iron alloys). Medicinal povidone iodine preparations include aerosol sprays, gauze pads, lubricating gels, creams, solutions, douche preparations, suppositories, gargles, perineal wash solutions, shampoos, and skin cleansers and scrubs. Povidone iodine preparation are applied topically to the skin and to membranes, e.g. vaginal membranes, and in infected wounds and surgical incisions. The uses continue to be largely medicinal, though some iodophors are used in industrial sanitation and disinfection in hospitals, building maintenance, and food-processing operations. There has been some interest in the use of iodine for purification of potable water and swimming pools. Two other iodine-containing compounds, p-tolyl diiodomethyl sulfone and p-chlorophenyldiiodomethyl sulfone have been recommended as preservatives.
Iodine and iodine-containing compounds and preparations are employed extensively in medicine, eg, as antiseptics, as drugs administered in different combinations in the prophylaxis and treatment of certain diseases, and as therapeutic agents in various thyroid dyscrasias and other abnormalities. Iodine is a highly reactive substance combining with proteins partly by chemical reaction and partly by adsorption. Therefore its antimicrobial action is subject to substantial impairment in the presence of organic matter such as serum, blood, urine, milk, etc. However, where there is no such interference, non-selective microbicidal action is intense and rapid. A saturated aqueous solution of iodine exhibits anti-bacterial properties. However, owing to the low solubility of iodine in water (33 mg/100 ml at 25° C.), reaction with bacteria or with extraneous organic matter rapidly depletes the solution of its active content. Iodide ion is often added to increase solubility of iodine in water. This increase takes place by the formation of triiodide, I 2 +I - =I 3 - . An aqueous solution of iodine and iodide at a pH of less than 8 contains mainly free diatomic iodine I 2 and the triiodide I 3 - The ratio of I and I - depends upon the concentration of iodide.
An important solubilizing agent and carrier for iodine is polyvinyl pyrrolidone (povidone), one grade of which is identified as povidone USP. Povidone iodine, is widely used externally on humans as an antiseptic. Such products are marketed as Betadine and Isodine, povidone iodine products and the preparation of such products are described in U.S. Pat. Nos. 2,707,701, 2,826,532, and 2,900,305 to Hosmer and Siggia, assigned to GAF Corporation and in a number of GAF Corporation publications; see, e.g. Tableting with Povidone USP (1981 ) and Povidone Polyvinylpyrrolidone (1982). Povidone iodine powder contains approximately 85% povidone, 10% I and 5% Iodide. A 10% solution of this powder contains 1% free, available iodine. (Gershenfeld, Am. J. Surgery 94, 938 (1957)).
Under ordinary conditions, povidone is stable as a solid and in solution. The single most attractive property of povidone is its binding capability. This property has permitted utilization in numerous commercial applications. Small quantities of povidone stabilize aqueous emulsions and suspensions, apparently by its absorption as a thin layer on the surface of individual colloidal particles. The single most widely studied and best characterized povidone complex is that of povidone-iodine. For example, hydrogen triiodide forms a complex with povidone that is so stable that there is no appreciable vapor pressure. It is superior to tincture of iodine as a germicide.
The use of conventional povidone iodine, i.e. compositions which have an povidone to iodine ratio of under 10 to 1, typically 8.5 to 1, in vaginal treatments has been reported. Women being prepared for total abdominal hysterectomy were treated by insertion of povidone-iodine tampons that remained in the vagina until the end of the operation. Statistically significant decreases both in infectious morbidity and in the percentage of positive cultures from the cervix and vagina, at the time of the operation resulted from this use of povidone-iodine. Vaginal Preparation with Povidone-Iodine before Abdominal Hysterectomy, Zakut Z; Lotan M; Bracha Y, Clin Exp Obstet Gynecol 14 (1). 1987. 1-5. The use of povidone-iodine (`Betadine`) pessaries in the treatment of candidal and trichomonal vaginitis was reported by Henderson JN; Tait IB Curr Med Res Opin 1975, 3 (3) p157-62. In the Henderson et al study one hundred and thirty-five women suffering from trichomonal, candidal, or both infections simultaneously, were treated with povidone-iodine pessaries, 2 pessaries being inserted nightly. Ninety-nine women were given a 7-day course of treatment, but the results obtained were disappointing, and the authors do not recommend such a regime for routine treatment. Better results were obtained with the recommended 14-day course. A further 36 women suffering from chronic trichomonal and/or candidal infections which had previously resisted orthodox treatment were given a prolonged 28-day course of pessary treatment. The results obtained were very encouraging, 92% of the trichomonal and 96% of the candidal infections being cured. Furthermore, although povidone-iodine is slightly less effective in trichomoniasis, most patients suffering from a chronic infection (candidal, as well as trichomonal) were cured by the one preparation. Side-effects did occur. Subjective symptoms, especially any offensive odor, disappeared within 3 days of the start of the treatment. The authors recommend that the 28-day course of povidone-iodine pessaries is used in those cases where trichomoniasis or candidiasis has been a therapeutic problem in the past, particularly if the patient is currently on the oral contraceptive pill.
Other uses of povidone iodine in vaginal preparations and as a spermicidal preparations have been reported. The treatment of minor vaginal irritation with disposable povidone iodine preparation (Betadine Medicated Douche) in cases associated with infertility was reported by Beaton J H., et al, Int J Fertil 29 (2). 1984. 109-112. The effect of chemical intravaginal contraceptives and betadine on ureaplasma urealyticum was studied by Amortegui, A. J.; Melder, R. J.; Meyer, M. P.; Singh, B., CONTRACEPTION; 30(2), pp. 135-142 1984. The purpose of the study was to find a barrier contraceptive agent capable of controlling infections and sexual transmission of Ureaplasma urealyticum from the female genital tract, especially to help reduce non-gonococcal urethritis in males caused by this organism. In vitro antimicrobial activity of Betadine(TM-Purdue Frederick Co.) against the eight serotypes of the organism was investigated. The results indicate that some of these contraceptives produce partial inhibition of the Ureaplasma at low dilutions, while Betadine produces a ureaplasmicidal effect up to dilutions of 1:64. Quantitative studies of the interaction of polyvinylpyrrolidone iodine and spermatozoa were conducted by Pfannschmidt N; Nissen HP, Z Hautkr Nov. 15, 1988. In this study, 27 ejaculates were incubated together with polyvinyl pyrrolidone iodine diluted with physiological saline solution in various proportions. 10 minutes, 1 hour, 4 hours, and 20 hours later, we determined the percentages of mobile and viable spermatozoa in both the native and the incubated seminal fluid. 1% polyvinyl pyrrolidone iodine solution was totally spermicidal already after 10 minutes of incubation. 0.1% solution only slightly reduced the sperm motility and viability. 0.01% polyvinyl pyrrolidone iodine solution even resulted in a temporary increase of motility.
Douche preparations containing povidone iodine are widely used, and efforts have been made to treat and/or prevent vaginal infections with povidone iodine.
Notwithstanding considerable interest in povidone iodine-based spermicide-microbicides, no satisfactory product has been developed and frequent regular use of povidone iodine products frequently results in irritation of the vaginal membrane and considerable discomfort to the user. It also is evident that no effective physical form of povidone iodine for use as a spermicide-biocide has been available. The invention described hereinafter solves the problems, both recognized and unrecognized, that have plagued workers in this field.
SUMMARY OF THE INVENTION
Gels and foaming gels containing levels of iodine in the general range of about 1 to 5 weight percent and having a ratio of povidone to I very much higher than previously disclosed, a portion of the extra povidone being low molecular weight compound for use as spermicide-biocides are disclosed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
My studies on the effect of higher than normal povidone to iodine ratios on cells and tissues of several times have established that increasing the povidone to iodine ratio very substantially above the ratio found in previous formulations, i.e. to provide at least about a 50% higher povidone to iodine ratio, of at least about 15 parts by weight of povidone to 1 part by weight of iodine, and preferable at a ratio of above 20 parts povidone to 1 part of povidone, very significantly reduce detrimental effects on cells and tissues and irritation of membranes such as the vaginal membrane. This result has been shown even in relation to highly fragile cell membranes. For example, it has been found that high povidone to iodine ratios virtually eliminate lysis of cells.
It has also been discovered that polyvinyl pyrrolidone alone is capable of killing about 2 to 5 logs of virus in body fluids; consequently, the increase in povidone to iodine ratio is not a simple dilution of the biocidal value of iodine.
Efforts to formulate an effective spermicidal gel using conventional povidone iodine, MW>˜30,000 d, resulted in compositions that were either too fluid to retain any physical configuration for a period long enough to form a physical barrier to the entry of sperm into the uterus or so firm as to break too easily thereby opening cracks and passages through which the sperm may bypass the gel entirely.
It was also found that gels such as described above provided little if any lubricity and, indeed, generally tended to be so liquid as to be useless or so firm as to be likely to break into pieces which would be uncomfortable.
The compositions of this invention perform three very important functions:
First, the compositions formed an effective, retentive film, and which provide additional lubricity.
Second, the compositions were non-irritating.
Third, the compositions form gels and foams that would retain whatever physical configuration into which they were formed for a period of several minutes with only modest flow at body temperature and yet would flow when subjected to force without fragmenting.
The inclusion of low molecular weight povidone i.e. povidone having a molecular weight at least as low as 20 kd (LMW povidone) results in a compositions which have very high high-lubricity form a coherent film that entraps sperm mid semen totally eliminates or very greatly reduces the tendency of iodine to irritate the vaginal membrane.
The composition may be applied as a gel into the vagina as a lubricant, spermicide and virucide. In addition, the gel may contain a foaming agent such as pentane or, less desirably one of the chlorofluorocarbons, and contained under modest pressure until use. When applied the gel foams to partially fill the vagina.
Viscosity is widely used and widely misunderstood term. Viscosity standards within a given system when measured in the same manner may provide very precise indicia of molecular weights, stiffness, etc. However, no single system of viscosity measurements has been standardized so as to permit a precise definition of viscosity relationships in all systems. Accordingly, the best and most informative definition of the viscosity of the gels and foamed gels of this invention requires reference to observable characteristics. With these limitations in the language of the art and the uncertainty of viscosity relationships, the viscosity of the gels and foamed gels of this invention is described as follows.
Gels and foamed gels must be sufficiently firm that a cone of gel or foamed gel formed by drawing a glass stirring rod upwardly from a body of the same will hot visible slump at temperatures of between 37° C. for a period of at least 1 minute.
It will be appreciated that there are a very large number of formulations of the components as discussed that will result in a suitable vaginally protective gel or foamed gel lubricant, virucide and spermicide. The following examples are, therefore, merely illustrative and not limiting.
EXAMPLE I
Basic Formulation No. I
A gel is formulated of 5 parts LMW povidone, 5 parts of conventional povidone (MW from about 30 Kda to 50 Kda) and 10 parts of povidone iodine (povidone from about 30 Kda to 50 Kda) The above are solid powdered products. The powders are mixed and purified water is slowly added while stirring until a very thick gel is formed. This is a basic gel formulation which may completed using various constituents. This basic gel formulation is referred to hereinafter as Formula I. The povidone to iodine ratio in Formula I is about 20:1 and the iodine content is about 5 wt/% of the total solids. Forming a gel with an equal amount of water results in a 2.5 wt/% iodine content based on the total composition. The amount of water required will vary some from batch to batch depending upon the molecular weight of the povidone, which varies from lot to lot and batch to batch.
While povidone to iodine ratios of as low as about 15:1 and even slightly lower may be used, there is an increasing risk of membrane irritation if the povidone to iodine ratio is lower than about 15:1 to 17:1. The LMW povidone constitutes about 25 weight percent of the total povidone and povidone iodine. Amounts as low as about 1 weight percent as high as about 25 weight percent provide generally satisfactory lubricity and film forming characteristics. Higher amounts result in a sticky, adherent material but which lacks sufficient body to be an effective sperm barrier.
EXAMPLE II
Water is slowly to Formula I. Viscosity measurements are made periodically. Once a gel of acceptable viscosity is obtained, then any of the generally used rotating disk or cup viscometers may be used. However, a simple and effective viscosity measurement is a cone-slump measurement. Since the gel must not slump or flow over an extended period of time, the simple cone-slump test described above is satisfactory for laboratory work but a more standard production viscometer may be used in the manufacture of larger lots. Water is added slowly in increments to achieve a gel that can be pumped and extruded and which also has the specified viscosity.
EXAMPLE III
The process of Example II is followed except that the mixing is carried out at ambient laboratory temperature, or higher, in a closed pressure container filled with >1 atmosphere, preferably >3 atmospheres, of pentane. The mixing is continued until the gel is saturated with pentane.
Samples are viscosity tested in the same manner, except that when the cone is filled the gel foams and expands. The viscosity test is carried out with the cone filled with the foamed gel.
Gels may be packaged in insertable robes as are commonly used to introduce gels, creams, etc. into the vagina. A body of gel conforming to the vagina and covering the external uterine opening is formed. Some gel may enter the cervix of the uterus. During coitus the body of gel is, of course, disturbed but in most instances will prevent direct ejaculation of semen into the uterus and will quickly absorb the semen and immobilize the sperm. The reaction of iodine is quite rapid, even in low proportions in the Povidone iodine gel and the sperm will be killed before they have the opportunity to migrate to the uterus. In addition, and very importantly, the semen is very quickly incorporated into the very hygroscopic gel thereby preventing direct contact of the semen and the microbes carried therein with the vaginal membrane. The microbes, e.g. HIV, are killed virtually instantaneously and no infection results.
The user should be instructed to withdraw the insertion tube in such a manner as to form a layer of the gel, or foam, on the walls of the vagina. The gel deposited in the vagina can be manually spread over the internal vaginal walls and labia and vestibule to provide protection from microbes that may be carried on the surface or under the foreskin of the penis of the users partner in coitus.
While other forms of iodine could, in theory, be used to prevent the transmission of disease during sexual intercourse, none are suitable either because they are unduly irritating or because they do not reside on the membranes long enough and in a form that will intercept microbes carried on the penis or in the ejaculate.
It is noted in closing that the gel or foam may be left in the vagina for an extended period without discomfort or irritation of the vaginal membrane. A catamenial pad may be worn if desired to absorb the gel as it takes up moisture from the tissues and becomes less viscous. The user may, of course, use a douche after a suitable period of time to assure that a complete kill of sperm and microbes has been accomplished. A waiting period of 20 minutes to an hour is adequate for this purpose.
INDUSTRIAL APPLICATION
This invention finds application in health care industries and as a consumer product. | A virucidal, spermicidal vaginal gel consisting essentially of povidone iodine having a povidone to iodine ratio of about 15:1 or higher containing from about one percent to about twenty percent low molecular weight povidone having a molecular weight of about 20 kd or lower, the gel having a viscosity such that a conical body drawn from a body of the same does not visibly slump at 37C. for a period of at least one minute and a method of preventing sexual transmission of disease and preventing pregnancy using the same are disclosed. | 0 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a semiconductor nonvolatile memory, and particularly to a decode circuit suitable for an electrically data reprogrammable flash memory.
[0003] 2. Description of the Related Art
[0004] An EEPROM has been known as an electrically erasable programmable semiconductor nonvolatile memory. A general EEPROM takes a stacked structure in which a memory cell transistor has a floating gate electrode and a control gate electrode. Upon data erasure, a boost or step-up level (VPP: about 12V) higher than a power supply level (VCC) used in a normal circuit is applied to a control gate electrode (WL) to pull or draw out electrical charges from a flowing gate electrode, thereby controlling the amount of the electrical charges in the floating gate electrode. That is, the amount of the electrical charges in the floating gate electrode is reduced to thereby bring the memory cell transistor into conduction when the power supply level (VCC) is applied to the corresponding control gate electrode (WL). Upon reading, the control gate electrode (WL) is set to the power supply level (VCC) and a decision as to whether data is 1 or 0 is made according to conduction and non-conduction of the memory cell transistor. Thus, two cases arise in which the power supply level (VCC) is applied to the control gate electrode (WL) according to an operation mode and the step-up level (VPP) is applied thereto according to an operation mode.
[0005] FIG. 1 is a block diagram showing a control gate electrode type decode circuit (decode circuit) of a batch erasable programmable EEPROM (Flash EEPROM). FIGS. 2 through 5 are respectively configurational diagrams of respective circuits used in the decode circuit.
[0006] The decode circuit 1 comprises a predecode circuit 18 which inputs address signals A<1:0> and a control signal /CHIP brought to a ground level (VSS) at batch erasure, a redundant element 10 which holds and outputs a redundancy replacement flag (RDDEN) and redundant relief addresses (RA) set to a power supply level (VCC) where redundancy replacement is required, a redundancy determination circuit 12 which inputs the outputs (RA<1:0> and /RA<1:0>) of the redundant element and the outputs (XA<1:0> and /XA<1:0>) of the predecode circuit 18 , a redundancy selector 14 which inputs the outputs (RXA<1:0>) of the redundancy determination circuit 12 , the outputs (XA<1:0> and /XA<1:0>) of the predecode circuit 18 and the control signal /CHIP, a decoder array 16 which inputs the outputs (XEN and RXEN) of the redundancy selector 14 , the outputs (XA<1:0> and /XA<1:0>) of the predecode circuit 18 and a control signal (ERASE), and a charge pump circuit 20 which supplies a boost or step-up level (VPP) to a boost or step-up power supply line (VEP) when the control signal ERASE is of the power supply level (VCC), and supplies the power supply level (VCC) to the step-up power supply line (VEP) when the control signal ERASE is of the ground level (VSS).
[0007] The decoder array 16 comprises a plurality of decoders (XDEC) 50 through 56 each of which inputs one of the outputs XA<0> and /XA<0> of the predecode circuit 18 and one of the outputs XA<1> and /XA<1> thereof, and the output XEN of the corresponding redundancy selector 14 , a redundant decoder (RXDEC) 58 which inputs the output RXEN of the redundancy determination circuit 12 , and a level shifter (LS 1 ) which inputs the control signal (ERASE).
[0008] Each of the decoders (XDEC and RXDEC) comprises a logic gate (NA) which decodes each address, an inverter (INV) which inputs the output of the logic gate (NA), a transfer gate (CM 00 ) of which the source is connected to the output of the inverter (INV) and the drain is connected to its corresponding control gate electrode (WL), a level shifter (LS 0 ) which inputs the output of the logic gate (NA) and the output of the inverter (INV), and a transfer gate (CM 01 ) of which the source is connected to the output of the level shifter (LS 0 ) and the drain is connected to its corresponding control gate electrode (WL).
[0009] The transfer gate (CM 00 ) comprises a PMOS transistor whose gate is configured as the output (ER) of the level shifter LS 1 , and an NMOS transistor whose gate is configured as the output (ER) of the level shifter LS 1 .
[0010] The transfer gate (CM 01 ) comprises a PMOS transistor whose gate is configured as the output (ER) of the level shifter LS 1 , and an NMOS transistor whose gate is configured as the output (ER) of the level shifter LS 1 .
[0011] The operation of the conventional decode circuit 1 will be explained below with being divided into a read operation (a), an erase operation (b) and a batch erase operation (c).
[0000] (a) Read Operation
[0012] When data is read from the EEPROM-(Flash EEPROM), a control signal /CHIP is set to a power supply level (VCC) and a control signal ERASE is held at a ground level (VSS) In this condition, address signals A<1:0> are inputted. Owing to the setting of the control signal /CHIP to the power supply level (VCC) at this time, a step-up power supply line (VEP) assumes the power supply level (VCC) and the control signal ERASE is set to the ground level (VSS). Thus, the output ER of the level shifter LS 1 results in the ground level (VSS) and the output /ER thereof assumes the power supply level (VCC)
[0013] The outputs (RDDEN, RA<1:0 and /RA<1:0>) of the redundant element 10 respectively hold a predetermined logic level. That is, when no redundancy replacement is required, the RDDEN is held at the ground level (VSS), whereas when the redundancy replacement is required, the RDDEN holds the power supply level (VCC) and redundancy relief address data holds a potential corresponding to a control gate electrode WL<m> (where m=0, 1, 2 and 3) that needs replacement.
[0014] When address signals A<1:0> are inputted, the predecode circuit 18 converts the address signal A<n> (where n=0 and 1) into complementary address signals XA<n> (where n=0 and 1) and /XA<n> (where n=0 and 1) and outputs them.
[0015] If the value of the output RA<n> (where n=0 and 1) of the redundant element 10 is of the power supply level (VCC), then the redundancy determination circuit 12 outputs the address signal XA<n> (where n=0 and 1) to the corresponding redundant address RXA<n> (where n=0 and 1), whereas if the value of the output RA<n> (where n=0 and 1) is of the ground level (VSS), then the redundancy determination circuit 12 outputs the address signal /XA<n> (where n=0 and 1) to the corresponding redundant address RXA<n> (where n=0 and 1).
[0016] That is, when the value of the output RXA<n> (where n=0 and 1) of the redundancy determination circuit 12 is of the power supply level (VCC), the value of the RA<n> (where n=0 and 1) assumes the power supply level (VCC) and the address signal XA<n> (where n=0 and 1) is brought to the power supply level (VCC). Alternatively, the value of the /RA<n> (where n=0 and 1) assumes the power supply level (VCC) and the address signal /XA<n> (where n=0 and 1) assumes the power supply level (VCC). Thus, the input address A<n> (where n=0 and 1) and the redundant relief address RA<n> (where n=0 and 1) are brought into coincidence.
[0017] When information (based on XA<1:0> and /XA<1:0> outputted from the predecoder 18 and RXA<1:0> outputted from the redundancy determination circuit 12 ) about the coincidence of the input addresses A<1:0> and the redundant relief addresses RA<1:0> is transmitted to the redundancy selector 14 , the redundancy selector ANDs all the redundant addresses RXA<1:0> and the redundancy replacement flag RDDEN to thereby make a decision as to whether or not redundancy replacement is required. When the redundancy replacement is required, the redundancy selector outputs the power supply level (VCC) and the ground level (VSS) to the RXEN and XEN respectively. When no redundancy replacement is required, the redundancy selector outputs the ground level (VSS) and the power supply level (VCC) to the RXEN and XEN respectively.
[0018] Each of the decoders constituting the decoder arrays 50 through 58 ANDs one of the address signals (XA<0> and /XA<0>), one of the address signals XA<1> and /XA<1>, and the output XEN of the redundancy selector and thereby selects the corresponding control gate electrode WL<m> (where m=0, 1, 2 and 3). Further, the corresponding redundant control gate electrode RWL is selected according to the output RXEN of the redundancy selector.
[0019] When no redundancy replacement is required, for example, that is, the XEN is of the power supply level (VCC) and the RXEN is of the ground level (VSS), the input addresses A<1:0> are transmitted from the predecoder 18 to the decoders, and the result of a decision as to whether the redundancy replacement is required, is transmitted to each corresponding decoder via the predecoder circuit 18 and the redundancy determination circuit 12 , whereby the control gate electrode WL<m> (where m=0, 1, 2 and 3) corresponding to the input addresses A<1:0> is selected.
[0020] When the redundancy replacement is required, that is, the XEN is of the ground level (VSS) and the RXEN is of the power supply level (VCC), the result of a decision as to whether the redundancy replacement is required, is transmitted to the corresponding decoder via the predecoder 18 , redundancy determination circuit 12 and redundancy selector 14 so that the corresponding redundancy control gate electrode RWL is selected.
[0021] Since, at this time, the result of the decision as to whether the redundancy replacement is required, is transmitted to the corresponding decoder via the predecoder 18 , redundancy determination circuit 12 and redundancy selector 14 , the control gate electrodes WL<3:0> are brought to non-selection.
[0022] In the decoder which drives the selected control gate electrode, the output of a logic gate NA changes from the power supply level (VCC) to the ground level (VSS), and the output of an inverter INV changes from the ground level (VSS) to the power supply level (VCC). Since, at this time, a gate signal ER of a PMOS transistor constituting the transfer gate (CM 00 ) and a gate signal /ER of an NMOS transistor constituting the transfer gate (CM 00 ) are of the ground level (VSS) and the power supply level (VCC) respectively, the selected control gate electrode WL is driven to the power supply level (VCC) by the transistors constituting the transfer gate (CM 00 ).
[0023] During the above operation, the control signal ERASE holds the ground level (VSS), and the charge pump circuit 20 inputted with the control signal ERASE supplies the power supply level (VCC) to the step-up power supply line (VEP).
[0000] (b) Erase Operation
[0024] When the data stored in the EEPROM (Flash EEPROM) is erased, a control signal /CHIP is set to a power supply level (VCC) and a control signal ERASE is held at a ground level (VSS). In this condition, address signals A<1:0> are inputted. Owing to the setting of the control signal /CHIP to the power supply level (VCC) at this time, a step-up power supply line (VEP) assumes the power supply level (VCC) and the control signal ERASE is set to the ground level (VSS). Thus, the output ER of the level shifter LS 1 takes the ground level (VSS) and the output /ER thereof assumes the power supply level (VCC). The outputs (RDDEN, RA<1:0> and /RA<1:0>) of the redundant element 10 respectively hold a predetermined logic level.
[0025] When no redundancy replacement is required, the RDDEN holds the ground level (VSS)). When the redundancy replacement is required, the RDDEN holds the power supply level (VCC)), redundancy relief address data holds a potential corresponding to a control gate electrode WL<m> (where m=0, 1, 2 and 3) that needs replacement.
[0026] When the address signals A<1:0> are inputted, the predecode circuit 18 converts the address signal A<n> (where n=0 and 1) into complementary address signals XA<n> (where n=0 and 1) and /XA<n> (where n=0 and 1) and outputs them.
[0027] If the value of the output RA<n> (where n=0 and 1) of the redundant element 10 is of the power supply level (VCC), then the redundancy determination circuit 12 outputs the address signal XA<n> (where n=0 and 1) to the corresponding redundant address RXA<n> (where n=0 and 1), whereas if the value of the output RA<n> (where n=0 and 1) is of the ground level (VSS), then the redundancy determination circuit 12 outputs the address signal /XA<n> (where n=0 and 1) to the corresponding redundant address RXA<n> (where n=0 and 1).
[0028] When the value of the output RXA<n> (where n=0 and 1) of the redundancy determination circuit 12 is of the power supply level (VCC), the value of the RA<n> (where n=0 and 1) assumes the power supply level (VCC) and the address signal XA<n> (where n=0 and 1) is brought to the power supply level (VCC). Alternatively, the value of the /RA<n> (where n=0 and 1) assumes the power supply level (VCC) and the address signal /XA<n> (where n=0 and 1) assumes the power supply level (VCC). Thus, the input address A<n> (where n=0 and 1) and the redundant relief address RA<n> (where n=0 and 1) are brought into coincidence.
[0029] When information about the coincidence of the input addresses A<1:0> and the redundant relief addresses RA<1:0> is transmitted to the redundancy selector 14 via the predecoder 18 and the redundancy determination circuit 12 , the redundancy selector 14 ANDs all the redundant addresses RXA<1:0> and the redundancy replacement flag RDDEN to thereby make a decision as to whether or not redundancy replacement is required. When the redundancy replacement is required, the redundancy selector outputs the power supply level (VCC) and the ground level (VSS) to the RXEN and XEN respectively. When no redundancy replacement is required, the redundancy selector outputs the ground level (VSS) and the power supply level (VCC) to the RXEN and XEN respectively.
[0030] Each of the decoders constituting the decoder array 16 ANDs one of the address signals XA<0> and /XA<0>, one of the address signals XA<1> and /XA<1>, and the output XEN of the redundancy selector 14 and thereby selects the corresponding control gate electrode WL<m> (where m=0, 1, 2 and 3). Further, the corresponding redundant control gate electrode RWL is selected according to the output RXEN of the redundancy selector 14 .
[0031] When no redundancy replacement is required, for example, that is, the XEN is of the power supply level (VCC) and the RXEN is of the ground level (VSS), the input addresses A<1:0> are transmitted from the predecoder 18 to the decoders, and the result of a decision as to whether the redundancy replacement is required, is transmitted to the corresponding decoder via the predecoder 18 , the redundancy determination circuit 12 and the redundancy selector 14 , whereby the control gate electrode WL<m> (where m=0, 1, 2 and 3) corresponding to the input addresses A<1:0> is selected.
[0032] When the redundancy replacement is required, that is, the XEN is of the ground level (VSS) and the RXEN is of the power supply level (VCC), the result of a decision as to whether the redundancy replacement is required, is transmitted to the corresponding decoder via the predecoder 18 , the redundancy determination circuit 12 and the redundancy selector 14 so that the corresponding redundancy control gate electrode RWL is selected.
[0033] Since, at this time, the result of the decision as to whether the redundancy replacement is required, is transmitted to the corresponding decoder via the predecoder 18 , redundancy determination circuit 12 and redundancy selector 14 , the control gate electrodes WL<3:0> are brought to non-selection.
[0034] When the control signal ERASE is next raised from the ground level (VSS) to the power supply level (VCC), the charge pump circuit 20 inputted with the control signal ERASE supplies a step-up level (VPP) to its corresponding step-up power supply-line (VEP), and the output /ER of the level shifter (LS 1 ) is changed to the ground level (VSS) and the output ER thereof is transitioned to the step-up level (VPP).
[0035] Owing to the supply of the step-up level (VPP) to the step-up power supply line (VEP), the output of the level shifter (LS 0 ) in the decoder which drives the selected control gate electrode, is changed to the step-up level (VPP) and the output /ER thereof is brought to the ground level (VSS), whereby the selected control gate electrode is driven to the step-up level (VPP) through the corresponding level shifter (LS 0 ) and transfer gate (CM 01 ).
[0000] (c) Batch Erase Operation
[0036] When the data of the EEPROM (Flash EEPROM) is collectively erased, a control signal /CHIP is first set to a power supply level (VCC) and a control signal ERASE is held at a ground level (VSS). Owing to the setting of the control signal /CHIP to the power supply level (VCC) at this time, a step-up power supply line (VEP) assumes the power supply level (VCC) and the control signal ERASE is set to the ground level (VSS). Thus, the output ER of the level shifter LS 1 takes the ground level (VSS) and the output /ER thereof assumes the power supply level (VCC). The outputs (RDDEN, RA<1:0> and /RA<1:0>) of the redundant element respectively hold a predetermined logic level.
[0037] When no redundancy replacement is required, the RDDEN holds the ground level (VSS). When the redundancy replacement is required, the RDDEN holds the power supply level (VCC), redundancy relief address data holds a potential corresponding to a control gate electrode WL<m> (where m=0, 1, 2 and 3) that needs replacement.
[0038] When the control signal /CHIP is transitioned to the ground level (VSS) in this condition, the predecode circuit 18 outputs the power supply level (VCC) to both of complementary address signals XA<n> (where n=0 and 1) and /XA<n> (where n=0 and 1).
[0039] Since both of the complementary address signals XA<n> (where n=0 and 1) and /XA<n> (where n=0 and 1) are of the power supply level (VCC), the redundancy determination circuit 12 outputs the power supply level (VCC) to the redundant addresses RXA<1:0> without depending on the output RA<n> (where n=0 and 1) of the redundant element 10 . Since the control signal /CHIP is of the ground level (VSS), the redundancy selector 14 outputs the power supply level (VCC) to both of the XEN and RXEN.
[0040] On the other hand, each of the decoders constituting the decoder array 16 ANDs one of the address signals XA<0> and /XA<0>, one of the address signals XA<1> and /XA<1>, and the output XEN of the redundancy selector 14 and thereby selects the corresponding control gate electrode WL<m> (where m=0, 1, 2 and 3). Further, the corresponding redundant control gate electrode RWL is selected according to the output RXEN of the redundancy selector 14 . However, all the control gate electrodes WL<3:0> and the redundant control gate electrode RWL are selected to bring all of the inputs of the decoders and redundant decoder to the power supply level (VCC).
[0041] In the decoder which drives the selected control gate electrode, the output of a logic gate NA changes from the power supply level (VCC) to the ground level (VSS), the output of an inverter INV changes from the ground level (VSS) to the power supply level (VCC), and the output of a level shifter (LS 0 ) is transitioned to the power supply level (VCC).
[0042] When the control signal ERASE is next raised from the ground level (VSS) to the power supply level (VCC), the charge pump circuit 20 supplies a step-up level (VPP) to its corresponding step-up power supply line (VEP), and the output /ER of a level shifter (LS 1 ) is changed to the ground level (VSS) and the output ER thereof is transitioned to the step-up level (VPP).
[0043] Owing to the supply of the step-up level (VPP) to the step-up power supply line (VEP), the output of the level shifter (LS 0 ) in the decoder which drives the selected control gate electrode, is changed to the step-up level (VPP) and the output /ER thereof is brought to the ground level-(VSS), whereby the selected control gate electrode is driven to the step-up level (VPP) through the corresponding level shifter (LS 0 ) and transfer gate (CM 01 ).
[0044] Since the control gate electrode is driven to a step-up level (VPP: about 12V) higher than a power supply level (VCC) used in a normal circuit upon data erasure in the EEPROM (Flash EEPROM), all the MOS transistors connected to the control gate electrodes and the boost or step-up power supply line (VEP) need a withstand voltage greater than the step-up level (VPP: about 12V).
[0045] In general, high withstanding of each MOS transistor is realized by thickening a gate oxide film and lengthening a gate length to thereby relax an electric field between respective terminals of the MOS transistors. However, a problem arises in that the MOS transistors are reduced in drive capacity.
[0046] In the conventional decode circuit, the level shifters (LS 0 and LS 1 ) and the transfer gates (CM 00 and CM 01 ) are respectively made up of high-withstand MOS transistors. However, the control gate electrode at reading is driven through the transfer gate (CM 00 ). Thus, the reduction in the drive capacity of each of the MOS transistors constituting the transfer gate (CM 00 ) incurs a delay in the operation of the control gate electrode. This delay is noticeable in particular upon the rise of a control gate electrode (WL) by a P type MOS transistor lower in channel mobility.
[0047] As a method of suppressing the delay in the rise of the control gate electrode, there has been known a method of expanding a gate width of each of P type MOS transistors constituting a transfer gate (CM 00 ) to thereby ensure drive capacity of the transfer gate (CM 00 ). Since, however, the transfer gate (CM 00 ) needs a long gate width for the purpose of its high withstanding and is required for each control gate electrode, an increase in layout area cannot be avoided.
[0048] Even in the case of either a case in which the control gate electrode WL<m> (where m=0, 1, 2 and 3) is selected or a case in which the control gate electrode WL<m> (where m=0, 1, 2 and 3) is not selected, the conventional decode circuit needs the transfer of the result of a decision as to whether redundancy replacement is required, to the corresponding decoder via a predecoder, a redundancy determination circuit and a redundancy selector in addition to a path through which the input address A<n> is transmitted. Therefore, a delay in reading occurs in the path.
[0049] In the conventional decode circuit, all the control gate electrodes (WL<3:0> and RWL) are driven to the step-up level (VPP) upon batch erasure regardless of whether the redundant relief is required. There is, however, a possibility that when a defect with a leak has occurred in the control gate electrode WL<m> (where m=0, 1, 2 and 3), for example, the control gate electrode WL<m> (where m=0, 1, 2 and 3) having such a leak will be driven to a step-up level (VPP), thus causing a reduction in the step-up level (VPP) due to the leak from the control gate electrode WL<m> (where m=0, 1, 2 and 3). On the other hand, since a control gate electrode WL<i> (where i≠m) having no defect is also driven to the step-up level (VPP), there is a possibility that a failure will occur even in the control gate electrode WL<i> (where i≠m) having no defect where the step-up level (VPP) is reduced.
SUMMARY OF THE INVENTION
[0050] The present invention has been made in view of the foregoing problems. It is an object of the present invention to provide a nonvolatile semiconductor memory device capable of making a reading speed faster and reducing a layout area.
[0051] According to one aspect of the present invention, for achieving the above object, there is provided a nonvolatile semiconductor memory device comprising memory cell transistors. A control gate electrode of each memory cell transistor is configured so as to be able to assume a first power supply potential (VCC) and a second power supply potential (VPP) higher than the first power supply potential upon its operation. A second NMOS transistor is provided between the gate of a first NMOS transistor which drives the control gate electrode (WL) to the first power supply potential (VCC) and a control signal (/ER) connected to the gate thereof. The source of the second NMOS transistor is inputted with the control signal (/ER), and the drain thereof is connected to the gate of the first NMOS transistor. A PMOS transistor is disposed in parallel with the first NMOS transistor. A transfer gate comprising these NMOS and PMOS transistors drives the control gate electrode (WL).
[0052] The above and further objects and novel features of the invention will more fully appear from the following detailed description appended claims and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] FIG. 1 is a block diagram showing a configuration of a conventional decode circuit;
[0054] FIG. 2 is a circuit diagram illustrating an internal configuration of a conventional redundancy selector;
[0055] FIG. 3 is a diagram depicting a redundant element;
[0056] FIG. 4 is a circuit diagram showing an internal configuration of a redundancy determination circuit;
[0057] FIG. 5 is a block diagram illustrating a configuration of a conventional decoder array;
[0058] FIG. 6 is a block diagram depicting a specific example of a decode circuit of the present invention;
[0059] FIG. 7 is a block diagram showing a configuration of a redundancy selector array of the present invention; and
[0060] FIG. 8 is a block diagram illustrating a configuration of a decoder array of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0061] Preferred embodiments of the present invention will be explained hereinafter in detail with reference to the accompanying drawings.
[0062] FIG. 6 is a block diagram showing a configuration of a control gate electrode (WL) type decode circuit of the present invention. FIGS. 7 and 8 are respectively configurational diagrams of respective circuits employed in the present decode circuit. A redundant element and a redundancy determination circuit are similar to the conventional circuits.
[0063] The present decode circuit 60 comprises a predecode circuit 68 which inputs address signals A<1:0> and a control signal /CHIP, a redundant element 10 which holds and outputs a redundancy replacement flag (RDDEN) and a redundant relief address (RA) set to a power supply level (VCC) where redundancy replacement is required, a redundancy determination circuit 12 which inputs the outputs (RA<1:0>, /RA<1:0>) of the redundant element and the outputs (XA<1:0>, /XA<1:0>) of the predecode circuit 68 , a redundancy selector array 64 which inputs the outputs (RDDEN, RA<1:0>, /RA<1:0>) of the redundant element, a decoder array 66 which inputs the output (RDDEN) of the redundant element 10 , the outputs (XEN<3:0>) of the redundancy selector array 64 , the outputs (RXA<1:0>) of the redundancy determination circuit 12 , the outputs (XA<1:0>, /XA<1:0>) of the predecode circuit 68 , and a control signal ERASE, and a charge pump circuit 70 which supplies a boost or step-up level (VPP) to a step-up power supply line (VEP) in response to a power supply level (VCC) of the control signal ERASE and supplies a power supply level (VCC) to its corresponding step-up power supply line (VEP) in response to a ground level (VSS) of the ERASE.
[0064] The redundancy selector array 64 comprises a plurality of redundancy selectors each of which inputs one of the outputs RA<0> and RA/<0> and one of the outputs RA<1> and /RA<1>, and RDDEN.
[0065] The decoder array 66 comprises a plurality of decoders (XDEC) each of which inputs one of the outputs XA<0> and /XA<0> of the predecode circuit 68 and one of the outputs XA<1> and /XA<1> thereof, and the output XEN<M> (where m=0, 1, 2 and 3) of the corresponding redundancy selector, a redundant decoder (RXDEC) which inputs the outputs RXA<1:0> of the redundancy determination circuit 12 and the output RDDEN of the redundant element 10 , and a level shifter (LS 1 ) which inputs the control signal (ERASE).
[0066] Each of the decoders (XDEC and RXDEC) comprises a logic gate (NA) which decodes each address, an inverter (INV) which inputs the output of the logic gate (NA), a transfer gate (CM 00 ) of which the source is connected to the output of the inverter (INV) and the drain is connected to the control gate electrode (WL), a level shifter (LS 0 ) which inputs the output of the logic gate (NA) and the output of the inverter (INV), a transfer gate (CM 01 ) of which the source is configured as the output of the level shifter (LS 0 ) and the drain is configured as a control gate electrode (WL), and an NMOS transistor (NM 0 ) of which the source is configured as the output (/ER) of the level shifter LS 1 and the gate is biased to a power supply level (VCC).
[0067] The transfer gate (CM 00 ) comprises a PMOS transistor whose gate is connected to the output (ER) of the level shifter LS 1 , and an NMOS transistor whose gate is connected to the drain of the NMOS transistor (NM 0 ).
[0068] The transfer gate (CM 01 ) comprises a PMOS transistor whose gate is connected to the output (/ER) of the level shifter LS 1 , and an NMOS transistor whose gate is connected to the output (ER) of the level shifter LS 1 .
[0069] The operation of the decode circuit according to the specific example will be explained below with being divided into a read operation (a), an erase operation (b) and a batch erase operation (c).
[0000] (a) Read Operation
[0070] When data is read from an EEPROM (Flash EEPROM), a control signal /CHIP is set to a power supply level (VCC) and a control signal ERASE is held at a ground level (VSS). In this condition, address signals A<1:0> are inputted. Owing to the setting of the control signal /CHIP to the power supply level (VCC) at this time, the potential of the step-up power supply line (VEP) assumes the power supply level (VCC) and the control signal ERASE is set to the ground level (VSS). Thus, the output ER of the level shifter LS 1 takes the ground level (VSS) and the output /ER thereof assumes the power supply level (VCC), and the gate of the NMOS transistor constituting the transfer gate (CM 00 ) is brought to a potential (VCC−Vt) lower than the power supply level (VCC) by a threshold voltage.
[0071] The outputs (RDDEN, RA<1:0> and /RA<1:0>) of the redundant element 10 and the XEN<3:0> which determine logic, based on the outputs of the redundant element, respectively hold a predetermined logic level.
[0072] When no redundancy replacement is required (RDDEN is of the ground level (VSS)), all the outputs XEN<3:0> are maintained at the power supply level (VCC) respectively. When the redundancy replacement is required (RDDEN is of the power supply level (VCC)), an output XEN<m> (where m=0, 1, 2 and 3) corresponding to a control gate electrode WL<m> (where m=0, 1, 2 and 3) of a cell that needs replacement, holds the ground level (VSS), and the output other than it, i.e., XEN<i> (where i≠m) holds the power supply level (VCC).
[0073] When address signals A<1:0> are inputted in this condition, the predecode circuit 68 converts the address signal A<n> (where n=0 and 1) into complementary address signals XA<n> (where n=0 and 1) and /XA<n> (where n=0 and 1) and outputs them. If the value of the output RA<n> (where n=0 and 1) of the redundant element 10 is of the power supply level (VCC), then the redundancy determination circuit 12 outputs the address signal XA<n> (where n=0 and 1), whereas if the value of the output RA<n> (where n=0 and 1) is of the ground level (VSS), then the redundancy determination circuit 12 outputs the address signal /XA<n> (where n=0 and 1) to the corresponding redundant address RXA<n> (where n=0 and 1).
[0074] When the value of the redundant address RXA<n> (where n=0 and 1) is of the power supply level (VCC), the value of the RA<n> (where n=0 and 1) assumes the power supply level (VCC) and the address signal XA<n> (where n=0 and 1) is brought to the power supply level (VCC). Alternatively, the value of the /RA<n> (where n=0 and 1) assumes the power supply level (VCC) and the address signal /XA<n> (where n=0 and 1) assumes the power supply level (VCC). Thus, the input address A<n> (where n=0 and 1) and the redundant relief address RA<n> (where n=0 and 1) are brought into coincidence.
[0075] On the other hand, each of the decoders (XDEC<0:3>) constituting the decoder array 66 ANDs one of the address signals XA<0> and /XA<0>, one of the address signals XA<1> and /XA<1>, and the output XEN<m> (where m=0, 1, 2 and 3) of the redundancy selector array and thereby selects the corresponding control gate electrode WL<m> (where m=0, 1, 2 and 3). The decoder RXDEC ANDs the outputs RXA<1:0> of the redundancy determination circuit 12 and the output RDDEN of the redundant element 10 and thereby selects the corresponding redundant control gate electrode RWL.
[0076] When the redundancy replacement is not required, that is, the RDDEN is of the ground level (VSS) or the input addresses A<1:0> are different from the redundant relief addresses RA<1:0> held in the redundant element, the input addresses A<1:0> are transferred from the predecode circuit 68 to the decoder so that a control gate electrodes WL<m> (where m=0, 1, 2 and 3) corresponding to the input addresses A<1:0> is selected.
[0077] When the redundancy replacement is required, that is, the RDDEN is of the power supply level (VCC) and the input addresses A<1:0> coincide with the redundant relief addresses RA<1:0> retained in the redundant element 10 , information about the coincidence of the input addresses A<1:0> and the redundant relief addresses RA<1:0> is transmitted to the corresponding redundant decoder so that the corresponding redundant control gate electrode RWL is selected. Since, at this time, the redundant relief addresses RA<1:0> held in the redundant element 10 are already transmitted to the decoder XDEC<m> (where m=0, 1, 2 and 3) through the redundancy selector RXSEL<m> (where m=0, 1, 2 and 3), the control gate electrode WL<m> (where m=0, 1, 2 and 3) corresponding to the input addresses A<1:0> is not selected.
[0078] In the decoder which drives the selected control gate electrode, the output of a logic gate NA changes from the power supply level (VCC) to the ground level (VSS). Thus, the output of an inverter INV is transitioned from the ground level (VSS) to the power supply level (VCC). Since, at this time, the gate of an NMOS transistor constituting a transfer gate (CM 00 ) is separated from /ER by an NMOS transistor NM 0 , the gate thereof is self-boosted to rise to a potential of about 2*VCC−Vt.
[0079] The control gate electrode of the selected cell is driven to the power supply level (VCC) by both the NMOS transistor and PMOS transistor constituting the transfer gate (CM 00 ).
[0080] The PMOS transistor constituting the transfer gate (CM 00 ) can also be deleted. Since, however, the gate potential of the NMOS transistor, which has been boosted by self boost, is considered to drop along the passage of time, this may preferably be utilized in combination to hold the control gate electrode at the power supply level (VCC).
[0081] During the above operation, the control signal ERASE holds the ground level (VSS), and the charge pump circuit inputted with the control signal ERASE supplies the power supply level (VCC) to the step-up power supply line (VEP).
[0000] (b) Erase Operation
[0082] When the data stored in the EEPROM (Flash EEPROM) is erased, a control signal /CHIP is set to a power supply level (VCC) and a control signal ERASE is held at a ground level (VSS). In this condition, address signals A<1:0> are inputted. Owing to the setting of the control signal /CHIP to the power supply level (VCC) at this time, a step-up power supply line (VEP) assumes the power supply level (VCC) and the control signal ERASE is set to the ground level (VSS). Thus, the output ER of the level shifter LS 1 takes the ground level (VSS) and the output /ER thereof assumes the power supply level (VCC), and the gate of a NMOS transistor constituting a transfer gate (CM 00 ) is brought to a potential (VCC−Vt) lower than the power supply level (VCC) by a threshold voltage.
[0083] The outputs (RDDEN, RA<1:0> and /RA<1:0>) of the redundant element and XEN<3:0> which determine logic, based on the outputs of the redundant element, respectively hold a predetermined logic level.
[0084] When no redundancy replacement is required (RDDEN is of the ground level (VSS)), all the outputs XEN<3:0> are maintained at the power supply level (VCC) respectively. When the redundancy replacement is required (RDDEN is of the power supply level (VCC)), an output XEN<m> (where m=0, 1, 2 and 3) corresponding to a control gate electrode WL<m> (where m=0, 1, 2 and 3) that needs replacement, holds the ground level (VSS), and the output other than it, i.e., XEN<i> (where i≠m) holds the power supply level (VCC).
[0085] When the address signals A<1:0> are inputted in this condition, the predecode circuit 68 converts the address signal A<n> (where n=0 and 1) into complementary address signals XA<n> (where n=0 and 1) and /XA<n> (where n=0 and 1) and outputs them therefrom.
[0086] If the value of the output RA<n> (where n=0 and 1) of the redundant element 10 is of the power supply level (VCC), then the redundancy determination circuit 12 outputs the address signal XA<n> (where n=0 and 1) to the corresponding redundant address RXA<n> (where n=0 and 1), whereas if the value of the output RA<n> (where n=0 and 1) is of the ground level (VSS), then the redundancy determination circuit 12 outputs the address signal /XA<n> (where n=0 and 1) to the corresponding redundant address RXA<n> (where n=0 and 1).
[0087] That is, when the value of the redundant address RXA<n> (where n=0 and 1) is of the power supply level (VCC), the value of the RA<n> (where n=0 and 1) assumes the power supply level (VCC) and the address signal XA<n> (where n=0 and 1) is brought to the power supply level (VCC). Alternatively, the value of the /RA<n> (where n=0 and 1) assumes the power supply level (VCC) and the address signal /XA<n> (where n=0 and 1) assumes the power supply level (VCC). Thus, the input address A<n> (where n=0 and 1) and the redundant relief address RA<n> (where n=0 and 1) are brought into coincidence.
[0088] On the other hand, each of decoders (XDEC<0:3>) constituting the decoder array 66 ANDs one of the address signals XA<0> and /XA<0>, one of the address signals XA<1> and /XA<1>, and the output XEN<m> (where m=0, 1, 2 and 3) of the redundancy selector array 64 and thereby selects the corresponding control gate electrode WL<m> (where m=0, 1, 2 and 3). The redundant decoder RXDEC ANDs the outputs RXA<1:0> of the redundancy determination circuit 12 and the output RDDEN of the redundant element 10 and thereby selects the corresponding redundant control gate electrode RWL.
[0089] When the redundancy replacement is not required, that is, the RDDEN is of the ground level (VSS) or the input addresses A<1:0> are different from the redundant relief addresses RA<1:0> held in the redundant element, the input addresses A<1:0> are transferred to the corresponding decoder so that a control gate electrode WL<m> (where m=0, 1, 2 and 3) corresponding to the input addresses A<1:0> is selected. When the redundancy replacement is required, that is, the RDDEN is of the power supply level (VCC) and the input addresses A<1:0> coincide with the redundant relief addresses RA<1:0> retained in the redundant element, information about the coincidence of the input addresses A<1:0> and the redundant relief addresses RA<1:0> is transmitted to the corresponding redundant decoder via the predecoder 68 and the redundancy determination circuit 12 so that the corresponding redundant control gate electrode RWL is selected.
[0090] Since, at this time, the redundant relief addresses RA<1:0> held in the redundant element 10 are already transmitted to the decoder XDEC<m> (where m=0, 1, 2 and 3), the control gate electrode WL<m> (where m=0, 1, 2 and 3) corresponding to the input addresses A<1:0> is not selected.
[0091] In the decoder which drives the selected control gate electrode, the output of a logic gate NA changes from the power supply level (VCC) to the ground level (VSS), the output of an inverter INV is transitioned from the ground level (VSS) to the power supply level (VCC), and the output of a level shifter (LS 0 ) changes to the power supply level (VCC).
[0092] When the control signal ERASE is raised from the ground level (VSS) to the power supply level (VCC), the charge pump circuit inputted with the control signal ERASE supplies a step-up level (VPP) to its corresponding step-up power supply line (VEP), and the output /ER of the level shifter (LS 1 ) is changed to the ground level (VSS) and the output ER thereof is transitioned to the step-up level (VPP).
[0093] Owing to the supply of the step-up level (VPP) to the step-up power supply line (VEP), the output of the level shifter (LS 0 ) of the decoder which drives the selected control gate electrode, is changed to the step-up level (VPP) and the output /ER thereof is brought to the ground level (VSS), whereby the selected control gate electrode is driven to the step-up level (VPP) through the corresponding level shifter (LS 0 ) and transfer gate (CM 01 ).
[0000] (c) Batch Erase Operation
[0094] When the data of the EEPROM (Flash EEPROM) is collectively erased, a control signal /CHIP is first set to a power supply level (VCC) and a control signal ERASE is held at a ground level (VSS). Owing to the setting of the control signal /CHIP to the power supply level (VCC) at this time, a step-up power supply line (VEP) assumes the power supply level (VCC) and the control signal ERASE is set to the ground level (VSS). Thus, the output ER of the level shifter LS 1 takes the ground level (VSS) and the output /ER thereof assumes the power supply level (VCC).
[0095] The outputs (RDDEN, RA<1:0> and /RA<1:0>) of the redundant element 10 and outputs XEN<3:0> which determine logic, based on the outputs of the redundant element, respectively hold a predetermined logic level.
[0096] When no redundancy replacement is required (RDDEN is of the ground level (VSS)), all the outputs XEN<3:0> are maintained at the power supply level (VCC) respectively. When the redundancy replacement is required (RDDEN is of the power supply level (VCC)), an output XEN<m> (where m=0, 1, 2 and 3) corresponding to a control gate-electrode WL<m> (where m=0, 1, 2 and 3) that needs replacement, holds the ground level (VSS), and the output other than it, i.e., XEN<i> (where i≠m) holds the power supply level (VCC).
[0097] When the control signal /CHIP is transitioned to the ground level (VSS) in this condition, the predecode circuit 68 outputs the power supply level (VCC) to both of complementary address signals XA<n> (where n=0 and 1) and /XA<n> (where n=0 and 1).
[0098] Since both of the complementary address signals XA<n> (where n=0 and 1) and /XA<n> (where n=0 and 1) are of the power supply level (VCC), the redundancy determination circuit 12 outputs the power supply level (VCC) to the redundant addresses RXA<1:0> without depending on the output RA<n> (where n=0 and 1) of the redundant element.
[0099] Each of the decoders (XDEC<0:3>) ANDs the address signals XA<0> (/XA<0>) and XA<1> (/XA<1>) and the output XEN<m> (where m=0, 1, 2 and 3) of the redundancy selector array 64 and thereby drives the corresponding control gate electrode WL<m> (where m=0, 1, 2 and 3).
[0100] The redundant decoder (RXDEC) ANDs the outputs RXA<1:0> of the redundancy determination circuit 12 and the output RDDEN of the redundant element 10 and thereby drives the corresponding redundant control gate electrode RWL.
[0101] Since, in this case, both the address signals XA<1:0> and /XA<1:0> are of the power supply level (VCC) and the redundant addresses RXA<1:0> are also of the power supply level (VCC), all the control gate electrode WL<3:0> are selected where, for example, no redundancy replacement is required, i.e., the RDDEN is of the ground level (VSS) and all of XEN<3:0> are of the power supply level (VCC). When the redundancy replacement is required, i.e., the RDDEN is of the power supply level (VCC)), an output XEN<m> (where m=0, 1, 2 and 3) corresponding to a control gate electrode WL<m> (where m=0, 1, 2 and 3) that needs replacement, is the ground level (VSS), and the output XEN<i> (where i≠m) other that it is of the power supply level, the corresponding control gate electrode WL<i> (i≠m) and redundant control gate electrode are selected.
[0102] In the decoder which drives the selected control gate electrode, the output of a logic gate NA changes from the power supply level (VCC) to the ground level (VSS), the output of an inverter INV changes from the ground level (VSS) to the power supply level (VCC), and the output of a level shifter (LS 0 ) changes to the power supply level (VCC).
[0103] When the control signal ERASE is next raised from the ground level (VSS) to the power supply level (VCC), the charge pump circuit 70 inputted with the control signal ERASE supplies a step-up level (VPP) to its corresponding step-up power supply line (VEP), and the output /ER of a level shifter (LS 1 ) is changed to the ground level (VSS) and the output ER thereof is transitioned to the step-up level (VPP).
[0104] Owing to the supply of the step-up level (VPP) to the step-up power supply line (VEP), the output of the level shifter (LS 0 ) of the decoder which drives the selected control gate electrode, is transitioned to the step-up level (VPP) and the output /ER thereof is brought to the ground level (VSS), whereby the selected control gate electrode is driven to the step-up level (VPP) through the corresponding level shifter (LS 0 ) and transfer gate (CM 01 ).
[0105] As described above, the NMOS transistor whose gate is biased to the power supply level (VCC), is added between the gate of the NMOS transistor constituting the transfer gate (CM 00 ) that drives the control gate electrode (WL) upon reading, and the control signal (/ER). Therefore, it is possible to set the gate of the NMOS transistor constituting the transfer gate (CM 00 ) to the potential greater than or equal to the power supply level (VCC) and drive the control gate electrode (WL) to the power supply level (VCC) by means of the NMOS transistor high in channel mobility as compared with the PMOS transistor. Thus, the present invention is capable of achieving the speeding-up of reading and area saving as compared with the case in which the control gate electrode (WL) is driven by the PMOS transistor.
[0106] The redundancy selectors (RXSEL) inputted with only the data (RA, /RA and RDDEN) programmed and retained in the redundant element in advance are provided for the respective decoders (XDEC), and the decoders are activated and deactivated by the outputs of the redundancy selectors, whereby the corresponding control gate electrodes (WL) can be selected without awaiting the result of a decision as to whether or not the redundancy replacement is required. Thus, it is possible to achieve the speeding up of reading, and an improvement in yield and an improvement in reliability by non-biasing of a control gate electrode (WL) with a defect to a high voltage.
[0107] While the preferred form of the present invention has been described, it is to be understood that modifications will be apparent to those skilled in the art without departing from the spirit of the invention. The scope of the invention is to be determined solely by the following claims. | The present invention provides a nonvolatile semiconductor memory device capable of achieving the speeding-up of reading and a reduction in layout area. A control gate electrode of each of memory cell transistors employed in the nonvolatile semiconductor memory device according to the present invention is configured so as to be capable of assuming a first power supply potential (VCC) and a second power supply potential (VPP) higher than the first power supply potential upon its operation. A second NMOS transistor is provided between the gate of a first NMOS transistor that drives a control gate electrode (WL) to the first power supply potential (VCC) and a control signal (/ER) connected to the gate thereof. The source of the second NMOS transistor is inputted with the control signal (/ER) and the drain thereof is connected to the gate of the first NMOS transistor. A PMOS transistor is provided in parallel with the first NMOS transistor. A transfer gate comprising these NMOS and PMOS transistors drives the control gate electrode (WL). | 6 |
This application is a continuation-in-part of U.S. Ser. No. 059,703, filed June 8, 1987 now U.S. Pat. No. 4,798,078 by the applicant of the present invention.
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for cutting metal bars, such as bars used during construction to reinforce concrete, generally known as rebars, and in particular to such a device which is portable and can be used on the ground at construction sites.
U.S. Pat. No. 4,594,875, issued June 17, 1986 to the inventor hereof, the disclosure of which is incorporated herein by reference, discloses and claims an improved rebar bending machine which is lightweight, hand operated and adapted to be used in the field by a single person. It has a laterally stabilized, elongated base and, mounted to the base a pair of spaced apart forming posts which straddle a slide mounted pair of lugs that form between them a groove into which rebar to be bent is placed. The slide is movable in an elongated guideway in a direction perpendicular to a line interconnecting the centers of the forming posts so that the groove defined by the lugs can be moved from a first position, at which a rebar placed in the groove is substantially tangent to the peripheries of the posts, past the line interconnecting the post centers, to a second position on the other side of the posts. In the course of this linear movement of the grooves a bend is formed in that portion of the rebar disposed between the lugs. Depending upon the length of travel of the lugs a bend of less than equal to or greater than 90° is formed in the rebar although 90° bends are by far the most common.
That patent further discloses to generate the relatively large bending forces with an elongated handle that is pivotally attached to the base. Suitable linkage connected to the handle and the slide translates the pivotal handle movements into linear slide motions.
To minimize the weight of the bending machine, and to maximize the bending force, the slide, post and linkage are arranged so that the slide does not travel substantially more than the distance it must travel to effect the greatest bend in the bar typically a bend of not more than about 120°. In this manner, the overall length of the device in general and of the slide, base and guideway in particular can be minimized, which saves weight, labor and costs. Within a given size and configuration of the machine, the bending force that can be generated with the manually operated handle can be maximized. An effective, high speed and accurate bending of the rebar is thus possible with the device of that patent.
Bending machines constructed in accordance with the above-mentioned patent have been on sale for more than a year and have met with exceptional success. It is believed that the success is to a large extent attributable to its compact size, relatively low weight and to its easy operation even on the uneven ground frequently encountered at construction sites.
At construction sites, it is frequently necessary to cut a bent or straight rebar. Although many rebar cutters are known and available, they are usually heavy, stationary, and/or machine-operated devices which, not infrequently, are relatively remote from the place where a rebar is being bent with a bending machine of the type disclosed in the '875 patent. Thus, the bar to be cut must be hand-carried to the cutting machine, wherever it may be located, cut, and then returned to the location where it will be used. This is time-consuming, for large diameter and/or long rebars constitutes heavy physical labor, and is, therefore, costly.
U.S. Ser. No. 059,703, now U.S. Pat. No. 4,798,078, the parent of the present application, discloses a machine for cutting rebar adapted to be attached to the improved rebar bending machine disclosed in the '875 patent discussed above. This cutting machine has a pair of closely adjacent cutting discs, one stationary and the other pivotal relative thereto, both of which include a peripherally open slot into which the rebar to be cut can be placed. The discs are mounted in a frame, preferably defined by two spaced apart, rigidly interconnected plates which have an upright portion through which a pivot shaft for the discs extends and a relatively horizontal portion which is used to connect the cutter with the rebar bending machine of the '875 patent.
In use, a rebar is placed in the aligned slots. An operator lowers the handle to move a slide and engage the roller of an arm connected to one of the cutting discs, causing relative movement of the discs and a corresponding rotational offset of the two slots of the discs, thereby severing the rebar. This cutter is a significant improvement over the prior art, allowing rebar cutting at the site with a simple, rugged, lowcost device. However, a relatively large force is still required to rotate the disc especially when cutting larger diameter rebar. The total force required to cut the rebar must be applied in one stroke. Thus, relatively heavy physical labor is still required. In particular, at times so much force must be applied to the handle that slightly built workers might have insufficient weight to push the handle down.
SUMMARY OF THE INVENTION
The present invention provides a significantly improved cutting machine which enhances the usefulness of the bending machine disclosed in the '875 patent, discussed above, by making it possible to cut, as well as bend, even relatively large diameter rebar with the same basic bending machine and at the location where the rebar is to be used, thereby eliminating the need to hand carry the rebar to a separate cutting machine. This cutting machine may be used by almost any construction worker because a significantly lesser force is required to operate it.
This is achieved, in accordance with the present invention, by providing a pair of closely adjacent cutting discs which are incrementally movable relative to each other through a "predetermined arc", i.e., that arc required to cut the rebar. Each disc includes an axially oriented groove which can be aligned with the groove of the other disc.
A force exerted by the construction worker in order to pivot the discs relative to each other moves the discs only an increment, i.e. through less than the predetermined arc, thereby reducing the total force that must be exerted in a single stroke. The first increment of relative movement begins to cut the rebar, although, alone, it is insufficient to sever it. With one or more additional increments of movement, the rebar is further cut until it is fully severed.
Generally speaking, the rebar cutting machine of the present invention has a pair of closely adjacent cutting discs, one stationary and the other pivotal relative to the one, both of which include a peripherally open groove into which the rebar to be cut can be placed. The discs are mounted in a frame, preferably defined by two spaced apart, rigidly interconnected plates which have an upright portion through which a pivot shaft for the discs extends, and a relatively horizontal portion which is used to connect the cutter to an activating mechanism. The pivot shaft is preferably a bolt which is sufficiently tightened to generate substantial friction between the discs. This facilitates the cutting of rebar and the operation of the devices as is further described below.
In the preferred embodiment of the invention the cutter is used with and actuated by a rebar bending machine as generally described in the above-referenced '875 patent, although other means for activating the cutter can be employed. Turning now momentarily to the construction of such a rebar bending machine, it has a base including a hollow guideway for the slide adjacent one end of the base. The guideway for the base is open and the slide is constructed and movable so that one end thereof projects from the open guideway end when the slide is in one of its limiting positions of travel. The guideway is at the end of the base which includes the lateral stabilizer.
The horizontal portion of the cutter frame includes an upwardly open recess into which the base and/or the lateral stabilizer can be dropped. The slots are formed so as to constrain the base to the horizontal portion of the cutter frame. i.e., to prevent relative movement between the two, both in a direction parallel to the slide movement and a (horizontal) direction perpendicular thereto.
The connection of the cutter to the bending machine is simple. The operator lifts the end of the bending machine, aligns it with the recess in the horizontal portion of the frame, and drops it into registration with the recess. Since the weight of the bending machine rests on the horizontal portion of the frame, the two are effectively constrained and secured to each other.
Although for operational purposes the rebar cutter can be permanently secured to the base of the bending machine, for example by welding, bolting, or otherwise permanently securing the base to the horizontal portion of the cutter frame, it is preferred to have the two easily detachable so that the bending machine can be used without the cutter. Thus, the cutter is coupled to the bending machine only when rebar cutting is required.
Turning now again to the cutting machine of the present invention, the movable disc includes a radial extension, a free end of which is spaced from and generally parallel to the horizontal portion of the frame. An obliquely inclined push bar has a first, lower end defined by a roller that is movable along a guide track formed by the horizontal portion of the frame in alignment and parallel to the reciprocating slide of the bending machine when the bending machine and the cutter of the present invention are operatively connected. A second, upper end of the push bar is proximate the free end of the radial extension of the movable disc and forms a plurality, e.g., three steps or recesses, each of which is engageable with the free end of the radial extension.
A link is pivotally connected to the radial extension and the second end of the push bar and constrains the two to each other while permitting limited relative movements between them in a manner further described below. In addition, a spring biases the upper end of the push bar towards the free end of the extension.
The rebar cutter of the present invention further includes a hook pivotally connected to the push bar, e.g., coaxially with the roller at the lower end thereof, and extending between the upright plates of the frame towards the bending machine so that the hook can be engaged with one of the lugs projecting upwardly from the reciprocating slide of the bending machine.
The push bar, the steps at the upper end thereof, and the free end of the radial extension of the movable disc are configured and positioned relative to each other so that when the axial cutting grooves of the discs are aligned, the lower end of the push bar is at its first or initial position where it is proximate the reciprocating slide of the bending machine when the slide is fully retracted into its elongated guideway. Activation of the handle of the bending machine moves the slide against the lower end of the push bar, thereby pushing it along the guide track formed by the frame of the cutter. As a result of the interengagement between the lug and the first step at the upper end of the push bar, the radial extension and therewith the movable disc are pivoted by an amount which is a function of the linear slide movement.
The push bar, the free end of the radial extension and the steps at the upper end of the push bar are formed and arranged so that for maximum pivotal movement of the bending machine handle the rotational movement of the first disc is less than the amount of rotational movement required to fully offset the rebar cutting grooves in the disc. In a present preferred embodiment the geometry is selected so that the movable disc pivots through an arc of approximately one-third to one-half the full predetermined arc the disc must be pivoted through to fully offset the rebar cutting grooves in the discs.
Upon the return movement of the slide from its terminal position toward its initial position, by raising the handle of the bending machine, the return hook pulls the lower end of the push bar with the slide. The significant friction generated between the stationary and movable discs referred to earlier prevents the latter from following the return movement of the push bar even though the two are interconnected by a spring biasing them towards each other. In addition the return link interconnecting the free end of the radial disc extension at the upper end of the push bar provides sufficient freedom of motion between the two so that the push bar, as its lower end follows the slide, permits relative slidable motions between the free end of the extension and the first step at the upper end of the push bar. When the free extension end reaches the second step in the push bar the biasing force exerted by the spring snaps the two together so that the free extension end seats in the second step of the push bar. This changes the connecting geometry between the two so that, immediately thereafter, the operator can again lower the handle of the bending machine. The slide again presses against the lower end of the push bar, and thereby causes a further incremental pivotal movement of the movable disc. This incremental advancement of the movable disc can be repeated any number of times, depending on the construction and geometry of the cutter that is employed, until the two grooves are fully offset from each other. At that point the rebar has been cut.
Thereafter, the operator raises the handle to fully retract the slide of the bending machine into its guideway and move it back to its initial position. The hook attached to the lower end of the push bar and engaging the slide follows this motion, thereby pulling the lower end of the push bar along with it.
The frame includes a guide which prevents the roller at the lower end of the push bar from lifting off the track during this return movement. In a preferred embodiment of the invention this guide is formed by a protrusion extending from an inside of one of the plates and positioned so as to engage a generally upwardly facing side thereof intermediate its two ends. As a result of this constraint on the path the push bar can follow during the return movement, the upper end of the push bar in effect pivots about the roller at the lower end while the roller remains in contact with or proximate to the track. The double pivoted link connecting the push bar and the free end of the radial extension follows the movement of the upper push bar end and thereby pivots the disc through the entire predetermined arc back to its original position at which the cutting grooves in the disc are axially aligned.
As a result of this construction of the cutting machine of the present invention rebar is cut by operating the pivotal actuating handle of the bending machine a plurality of times, e.g., two or three times to effect the pivotal movement of the cutting disc through the predetermined arc and thereby sever the rebar placed into the aligned cutting grooves of the disc. This significantly reduces the amount of force that must be applied by the worker to cut the bar. Thus even slightly built workers can readily operate it.
Cutting is further made easier because after the initial or first activation of the handle it needs to be raised only partially for each subsequent activation. This leaves the handle at a less steeply inclined orientation as that the workman has a better mechanical advantage when he applies a force e.g. his weight to the handle. In addition, when the operator retracts the slide, by raising the handle of the bending machine after the completion of an incremental cutting step, an audible click signals to him when he can reverse the handle motion and again push downwardly to pivotally advance the cutting disc an additional increment.
After the completion of the cut, however, return of the disc to its original position, in which the cutting grooves of both discs are aligned, is accomplished with a single reverse stroke of the handle from its inclined to its fully raised position. This reduces the amount of time required for readying the cutting machine of the present invention for another cut and, therefore, enhances its efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective, side elevational view of a cutting machine constructed in accordance with the present invention, with parts broken away, and illustrates the relative position of two cutting discs after the completion of a cut:
FIG. 2 is a fragmentary, side elevational view, partially in section, and illustrates the cutting machine of the present invention in operative engagement with a rebar bending machine used to actuate the cutter;
FIGS. 3-6 are fragmentary, schematic, side elevational views which sequentially illustrate the manner in the movable cutting disc of the cutter of the present invention is incrementally moved through a predetermined arc and returned to its original position:
FIG. 7 is a plan view of a rebar bending machine with which the cutter of the present invention is preferably used; and
FIG. 8 is a front elevational view in cross section and is taken on line 8--8 in FIG. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIGS. 1, 2, 7 and 8, and initially describing a portable, hand-operated rebar bending machine 2 with which a rebar cutter 4 of the present invention is preferably used, it comprises an elongated base 6, a bending mechanism 8 at one end of the base and an actuating handle 10 operatively coupled with the bending mechanism. To provide stability for the machine the base includes generally transversely oriented cross-legs 12 at one end thereof and a transversely extending yoke 14 at the other end of the base and which forms part of the bending mechanism. To reduce the weight of the machine while maintaining rigidity, the base and the cross-legs are preferably constructed from steel pipe.
Yoke 14 forms one end of the base and supports and houses the bending mechanism 8. It includes a tubular center section 16, which is secured, e.g. welded to or integrally constructed with the proximate end of an elongated steel pipe 18 which forms the major portion of the base, and a pair of angularly inclined arms 20, 22 which laterally protrude from the center section to either side thereof. The free ends of the arms are joined, e.g., welded together, for strength and rigidity. The upwardly facing surfaces of the center section 16 and arms 20, 22 are flat and lie in a common plane to define a flat, horizontal support surface for the rebar to be bent by the machine.
The tubular center section 16 of the yoke defines an internal, elongated, linear guideway 26 which has an open end facing cutter 4 and which linearly reciprocally mounts an elongated slide 28 which is movable between an initial or retracted position and a terminal or extended position. One end of the slide projects from the open guideway when the slide is in its terminal position.
The slide includes a pair of spaced apart lugs 30 which protrude through an elongated, upwardly open slot 32 in the tubular center section 16 of the yoke. The lugs have opposing convexly arcuate bending surfaces 34 which define between them a first groove 36 of a sufficient width so that straight rebar to be bent can be placed in to the groove. The height of the lugs is typically greater than the diameter of the largest rebar capable of being bent by the machine, i.e. the height is greater than the width of groove 36.
A pair of bending posts 38 are positioned on a line perpendicular to the guideway 26 at the outward ends of arms 20, 22. Each post comprises a shaft 40 firmly secured, e.g. welded to the yoke and protruding upwardly past the flat support surface 24. A roller 42 is rotatably carried by the protruding portion of the shaft 40 and is suitably restrained to the shaft to prevent relative axial movements of the roller. Each roller has a height greater than the diameter of the largest rebar capable of being bent by the machine and a concave peripheral surface 44 for nesting the rebar during bending.
Handle 10 is preferably an elongated section of steel pipe having a free end 46 which is proximate cross legs 12 and a second end which is pivotal about a pivot shaft 48 carried on supports 50 protruding upwardly from the base. A lever 52 fixed e.g. welded to the second end of the handle is angularly inclined relative to and extends from the handle past the pivot shaft towards guideway 26. A link 54 has its respective ends pivotally attached to the free end of the lever and the proximate end of slide 28. The link translates pivotal movements of handle 10 and the lever 52 into correspondingly reciprocating, linear movements of the slide 28 in guideway 26.
In use the lever is fully raised so that the groove between jaws 30 is disposed to the left of bending post rollers 42 as seen in FIG. 7. Next, rebar 4 is placed into the groove and the operator lowers handle 10 in a clockwise direction, as seen in FIG. 2, until it is in a substantially horizontal position. This causes a corresponding linear movement of the slide within guideway 26 and, thereby, moves jaws 30 from the left hand side of post 38 to the right hand side thereof. In the course of this movement a bend is formed in the rebar.
The rebar bending device is particularly adapted for use in the rough environment typically surrounding construction sites. It is relatively lightweight and is readily carried by one person. Cross-legs 12 and the laterally protruding arms 20, 22 of yoke 14 assure stability of the device even when placed on uneven ground. Tubular center section 16, which defines guideway 26, protects slide 26 from contact with abrasive ground, sand, etc. In addition slide 28 is relatively long, e.g. five to ten times its width, to provide accurate guidance as it reciprocates within guideway 26 without causing wedging even when the forces applied by lugs 30 to the rebar tend to skew the slide.
Still referring now to FIGS. 1, 2, 7 and 8, the construction of rebar cutter 4 of the present invention will be described in detail. It has a frame 60 including a pair of spaced apart, upright plates 62. Their lower ends are interconnected by a horizontal member 64, the upwardly facing surface of which defines a horizontal track 66. The frame further includes a forwardly (towards cutting machine 2) extending connector 68 defined by spaced apart, generally vertically oriented bars 70. Recesses 72 formed in the upper surfaces of the vertical bars have a depth equal to the height or thickness of angular arms 20, 22 of bending machine yoke 14. Further, ends 74 of the recesses are positioned and oriented so that the yoke can be placed into the recess with little play. For the illustrated embodiment, in which the yoke of the bending machine is diamond-shaped, the ends 74 of the recesses have angular orientations which correspond to the angular orientation of the sides of the yoke.
To connect cutter 4 of the present invention to a bending device 2, the cutter is placed on the ground and yoke 14 of the bending machine is lifted and positioned above recess 72 in cutter frame 60. The end of base 6 opposite from the yoke is preferably slightly raised, so as to incline the yoke and point the open end of the guideway slightly downwardly. When so inclined, the yoke is lowered to seat it in the recess, thereby aligning the open end of the guideway with the space between upright plates 62 of the frame and slightly above horizontal track 66. Thereafter, the opposite end of base 6 (from which cross-legs 12 extend) is lowered until the entire yoke is nested in the recess. At this point, the yoke is fully supported on the ground by vertical bars 70 of connector 68 and cross-legs 12 of the base support the opposite end thereof. The bending machine and the cutter of the present invention are now ready for use.
Returning now to the construction of cutter 4, a first, stationary disc 76 and a second, pivotable disc 78 are carried by a bolted shaft 80 extending between upright plates 62. The bolt is firmly tightened so that there is no play between the discs and sufficient friction is generated between them to prevent the pivotable disc from rotating freely on the disc, i.e., without the need to apply a substantial force to it.
The fixed disc includes a downwardly depending arm 82, the free end of which is secured to the proximate upright plate 62 with a bolt 84 extending through a slot 86 (illustrated in FIG. 1 only). The bolt prevents the arm, and thereby disc 76 from pivoting on shaft 80. A slot 86 permits slight adjustments of the position of the fixed disc. A threaded screw 87 on the side of plate 62 is preferably to facilitate precise adjustments in the position of the fixed disc.
The pivotable disc has a radial extension 88 that terminates in a free end 90 and includes a generally downwardly facing lug 92. Both discs further include at least one set of axially alignable rebar cutting grooves 94, 96. Groove 94 in the fixed disc is positioned so that it faces generally upwardly, as is clearly shown in FIG. 1, when bolt 84 secures arms 82 to the adjoining plate 62. If desired, a second set of axially alignable grooves 98 may be provided for cutting rebar of a different, e.g., smaller diameter, for example.
A push bar 100 operatively connects the free end 90 of extension 88 with slide 28 of bending machine 2 to effect relative pivotal movement of disc 76 through a predetermined arc in a plurality of increments from an original position, in which rebar cutting grooves 94, 96 are axially aligned, to a terminal position in which the grooves are fully axially offset (as illustrated in FIG. 1, for example). A lower end 102 of the push bar is appropriately bifurcated to provide space for a roller 104 which is mounted on a shaft 112 and rests on and can roll along track 66 of horizontal frame member 64. The lower end further pivotally mounts a return hook 106, the forward (towards bending machine 2) end of which has a notch 108 of a sufficient width so that the notch loosely engages the lug 30 on slide 28 of the bending machine closest to cutter 4. In a presently preferred embodiment of the invention, hook 106 has a bifurcated end 110 which straddles lower end 102 of the push bar. It is also secured to shaft 112.
As is best seen in FIG. 2, the end of slide 28 of bending machine 2 projecting from the open end of guideway 26 is opposite from a forwardly facing skirt 114 of the hook. When bending machine handle 10 is lowered and slide 28 is moved to the right, as seen in FIG. 2, to extend it from the open guideway end, the projecting end of the slide engages skirt 114 of the hook and thereby pushes the hook and the lower end of push bar 100 to the right, again as seen in FIG. 2. Notch 108 in hook 106 is dimensioned so that substantially no force is transmitted from lug 30 to the hook when the bending machine handle is operated to extend the slide out of its guideway. When the handle is raised, to retract the slide into the guideway, however, the lug 30 engages the notch in hook 106 to thereby pull the lower end 102 of the push bar with it.
An upper end 116 of the push bar is defined by a plurality, e.g. three successive steps or recesses 118, 120 and 122. The first step is lowest and closest to shaft 80 for pivotal disc 76 while step 122 is highest and furthest removed from the shaft. Further, a tension spring 124 has its respective ends attached to radial extension 88 and an upper portion of push bar, respectively. It biases the upper end of the push bar towards the radial extension.
A link 126 is used for the return of the disc from its terminal to its home position, as further described below, and has a first end pivotally secured to the radial extension 88 adjacent the free end 90 thereof. The other end of the link is pivotally attached to the upper end 116 of the push bar. An elongated slot in the link at one or the other pivot points thereof, say, at its pivot with the push bar permits limited relative movements between the lug 92 on the extension and steps 120, 122, 124 over a distance slightly greater than the height of one step for purposes further described below.
Referring now to FIGS. 1-8, with emphasis on FIGS. 3-6, the operation of cutter 4 of the present invention is as follows. Initially, the cutter is connected to bending machine 2 as was described above (or to another actuator), actuating handle is fully raised (to correspondingly fully retract slide 28 into guideway 26 to its initial position) and notch 108 in return hook 106 is engaged with lug 30 attached to the slide. The free end of the slide is now immediately opposite skirt 114 of the hook.
Cutting grooves 94, 96 in discs 76, 78 are aligned and a rebar to be cut (not separately shown) is placed into the aligned grooves. The relative positions of movable disc 78, extension 88 and push bar 100 are illustrated in the schematic of FIG. 3 in solid lines. It should be noted that lug 92 at the free end of radial extension 88 engages the first step 118 at the upper end 116 of the push bar. Tension spring 124 biases the push bar towards the extension and thus keeps the two engaged.
By lowering handle 10 of the bending machine a horizontally acting force, schematically shown in FIG. 3 by the arrow "F", is applied to the lower end 102 of the push bar. This forces the push bar to the right, as seen in FIG. 3. Since roller 104 engages track surface 66 and lug 92 is frictionally constrained to first step 118, the horizontal movement of the lower push bar end in effect results in a pivotal motion of the push bar about lug 92. This raises the upper end of the push bar into the position shown in FIG. 3 in phantom lines and correspondingly pivotally moves extension 88, and therewith disc 78 into the position shown in phantom lines.
The geometry of the push bar, the extension and the interengaging lug and steps are chosen so that for a maximum horizontal slide motion "S 1 " from its initial position to its terminal position, resulting from pivotal movement of the handle from its fully raised to its fully lowered horizontal position, disc 78 pivots through an arc which is less, say approximately one-half of the predetermined arc through which it must be rotated to fully offset rebar cutting grooves 94 and 96. When the slide is in its terminal position the grooves are offset as approximately shown in FIG. 3.
Once the handle has been fully lowered, the operator raises it to retract slide 28, and therewith return hook 106 to the left, as seen in FIG. 3. The lower end 102 of the push bar is thereby moved to the left also. The substantial friction between discs 76 and 79 maintains the pivotable disc 76 in its advanced position (illustrated in FIG. 3). i.e., it does not follow the return motion of the push bar. Instead, it leads to a slidable movement between lug 92 and the vertical wall of first step 118. Slot 128 in link 126 is of a sufficient length to permit this relative motion. In addition, tension spring 124 continuously biases push bar in a counterclockwise direction, as seen in FIG. 3, against lug 92. Consequently, the continued retraction of the slide into the guideway eventually aligns lug 92 with second step 120. When this occurs the biasing force of the spring snaps the push bar to the left, as seen in FIG. 3, to seat the lug in the second step. This causes a pronounced, audible click which advises the operator that he can again lower the handle to continue the cutting operation. It should be pointed out that this occurs before the slide has been returned to its initial position, i.e., when its return motion has covered a distance less than "S 1 ".
The relative position of the extension 88 and push bar 100 at the beginning of the second incremental pivotal motion of disc 78 through the predetermined arc is illustrated in FIG. 4. By lowering the handle 10 the operator again extends the slide to the right. This moves the lower end 102 of the push bar along track 66 to the right, as seen in FIG. 4, into the position shown in phantom lines, and pivotally moves the extension and the disc a further increment, also as illustrated in phantom lines in FIG. 4. At the end of the second increment, the relative axial offset of cutting grooves 94. 96 is approximately shown in FIG. 4.
Although the relative dimensioning and positioning of the components of the cutter may be selected so that cutting is completed at the end of the second increment, in the illustrated embodiment this is not the case. After the second cutting increment the cutting grooves are still not fully offset and, therefore, the rebar cutting operation is still not complete. Consequently, the operator repeats the incremental cutting operation by again raising the handle as discussed above to eventually place the push bar 100 and the radial extension 88 into the position shown in FIG. 5 in solid lines. Lug 92 engages the third, highest step 122 of the push bar. By lowering the handle the lower end of the push bar is again to the right, as seen in FIG. 5, into the position shown in phantom lines. This results in a further incremental rotation of the disc 76 and thereby completes its incremental pivotal movement through the predetermined arc. Cutting grooves 94, 96 are now fully axially offset and completing the rebar cutting step is complete.
As is apparent from the foregoing description of how the cutter 4 operates, the push bar and the radial extension of the movable disc, in conjunction with spring 104 and link 126 form in effect a ratchet mechanism for incrementally advancing the disc through the predetermined arc.
Since it is not necessary to move the handle to its fully raised position each incremental step its angular inclination at the start of the second and third steps is substantially less than at the beginning of the operation. Hence, it is easier for the operator to continue cutting because he has a greater available moment arm to push the handle downwardly than is the case when the handle is fully raised. This is of advantage because when severing rebar the amount of cutting force typically is lowest at the beginning of the cutting operation and becomes greatest shortly before the cut is completed. At these points the handle is much less steeply inclined and, therefore, a greater effective (horizontal) moment arm is available. Hence, cutting can be completed with a relatively smaller force.
Since the slide travels a lesser distance during the second and third handle activations, the horizontal distance travelled by the lower end 102 of the push bar during the second and third cutting steps becomes also less. Hence, "S 1 " (FIG. 3) is greater than "S 2 " (FIG. 4) and "S 3 " (FIG. 5).
Upon the completion of the cutting operation the operator grasps handle 10 and brings it to its fully raised position. This retracts slide 28, and with it return hook 106 and lower end 102 of the push bar the full distance "S 1 " to the left as seen in FIG. 6, until the slide reaches its initial position.
Referring now specifically to FIG. 6, the relative positions of radial extension 88 and push bar 102 at the end of the cutting operation are shown in solid lines. As the lower end 102 of the push bar is moved to the left, as seen in FIG. 6, a guide block 130 secured to one of the upright plates 62 of frame 60 and projecting towards the opposite plate, engages a generally upwardly facing surface 132 of the push bar. The guide block prevents the movable connections between slide lug 30, hook 106, lower push bar end 102, link 126 (after slot 128 thereof bottomed out and engages the pin extending therethrough), and extension 88 from "straightening" in a manner a chain straightens when subjected to tension. Instead the guide block constrains roller 104 to track 66 and induces a pivotal movement of the push bar about shaft 112 so that upper end 116 thereof moves pivotally downward (towards track 66). Link 126 transfers this downward motion to extension 88 and thereby pivots disc 76 to its home position.
It should be noted that in practice the movement of the push bar during the full return of the slide is not a precise pivotal movement about shaft 112. Due to required tolerances roller 104 will normally lift off track 66 and the actual path followed by the push bar will resemble a compound pivotal movement about guide block 130, or about a plurality of points along a short portion of upwardly facing surface 132 of the push bar.
A new cut is commenced by lowering handle 10 of the bending machine to initially move the lower end of the push bar to the right, from the position shown in FIG. 6 in phantom lines to a point where the pin engaging slot 128 and link 126 is spaced from the respective ends of the slot and lug 92 engages the first step 118 at the upper end of the push bar. This position is illustrated in FIG. 3 in solid lines. | A hand-operated rebar cutting apparatus including first and second discs carried by a shaft mounted on a frame. The discs are pivotable relative to each other and each includes grooves which can be aligned for receipt of a bar to be cut. The first discs is pivotal on a shaft carried by a frame and moves incrementally through a predetermined arc such that the grooves become substantially axially offset from each other. The appartus is attached to a manually operable bender and straightener having a linearly reciprocable slide mounted within a guideway. As the slide is reciprocated, the first and second discs of the apparatus are pivoted relative to each other. The apparatus includes a ratchet mechanism for allowing incremental pivoting of the discs relative to each other through the predetermined arc, while allowing reciprocable movement of the slide to its initial position without returning the first and second discs to the position in which the grooves are aligned. The apparatus also includes return means for pivotally returning the first discs in a second direction through the entire predetermined arc during a single return stroke of the slide. When the grooves are substantially axially offset from each other, a bar placed in the aligned groove is thereby cut. | 8 |
REFERENCE
This application is a continuation of PCT/EP2007/056208 filed Jun. 21, 2007 which is based on and claims priority to European Patent Application No. EP 06 116 245.9 filed Jun. 28, 2006, which are hereby incorporated by reference.
FIELD
The invention relates to a method for monitoring an arrangement for determining the concentration of an analyte in a body fluid in the body of a living human or animal, and to such an arrangement with corresponding monitoring means.
BACKGROUND
Arrangements of this kind are used in the prior art, for example, for monitoring glucose concentration in human blood. EP 0 722 288 relates to a method and a device for monitoring the concentration of a selected substance or a selected group of substances in a body fluid in the body of a living human or animal. The substance or group of substances to be monitored is conveyed out of the body through an interface and is transported away from the reverse side of the interface in a stream of perfusion liquid. The concentration of the substance or group of substances to be monitored is measured in the perfusion liquid downstream from the interface, the rate of flow of the stream of perfusion liquid being less than 60 μl/h.
DE 44 05 149 relates to an arrangement for determining the concentration of constituents in body fluids using a dialysis probe which can be implanted in body tissue and through which a perfusion solution flows, the inflow end of the dialysis probe being connected via a pump to a perfusion solution reservoir and the return flow end being connected to a collecting container via at least one enzyme cell serving as a sensor for the substance concentration. The enzyme cell output is connected to an extracorporeal evaluation/display unit. The perfusion solution reservoir, the pump, the enzyme cell and the collecting container are combined, separately from the evaluation/display unit, as a sensor unit in their own first housing. The dialysis probe, the perfusion solution reservoir, the pump, the enzyme cell and the collecting container are combined, separately from the evaluation/display unit, as a probe/sensor unit in their own second housing.
In such arrangements known in the prior art, a great many malfunctions can occur that have negative impacts on measurement accuracy. An incorrectly determined concentration value of the analyte can, however, have serious consequences for the person who is using the arrangement and who, for example, is controlling the administration of insulin as a function of the glucose concentration value that is determined. Consequently, reliable monitoring of the arrangement for determining the concentration of the analyte is necessary.
SUMMARY
The present invention avoids the disadvantages of the prior art and, in particular, provides a method for reliable monitoring of an arrangement for determining the concentration of an analyte in a body fluid.
The present invention provides a method for monitoring an arrangement for determining a concentration of an analyte in a body fluid, in which the determination of the concentration of the analyte by means of the arrangement involves a procedure in which the analyte from the body fluid passes through an interface and is transported in a stream of liquid into a flowmeter chamber, in which a measurement is carried out to determine the concentration of the analyte, and an evaluation of the measurement takes place in a signal processor. The monitoring of the arrangement comprises the following steps: measurement of measured values of at least two correlated system parameters of the arrangement by means of a sensor system, and comparison of the measured values with limit values stored for each of the system parameters in a storage unit, to obtain a combination of at least two comparison results.
The arrangement to be monitored comprises an interface through which the analyte (for example, glucose) can pass from the body fluid (for example, blood or interstitial fluid) into the arrangement. The body fluid, in which the concentration of the analyte is determined by the arrangement, can be in direct contact with the interface, or the concentration in the body fluid can be calculated indirectly from the concentration of the analyte in the liquid in contact with the interface. The interface is, for example, a semipermeable membrane in a microdialysis probe that is introduced subcutaneously into the tissue of a body. The semipermeable membrane separates the interstitial space from the interior of the probe and permits the diffusion of the analyte from the interstitial fluid into a perfusion liquid in the interior of the probe. However, the interface of the arrangement that is to be monitored can be in the form of any desired interface that allows the analyte to pass into the arrangement, in particular also an open window.
The analyte that has passed through the interface is transported in a stream of liquid (stream of perfusion liquid/stream of dialysate) into a flowmeter chamber. The perfusion liquid (for example, an isotonic analyte-free liquid) is preferably transported by a transport device (in particular a pump, for example, a micro-mechanical diaphragm pump or a roller pump) from a reservoir to the interface and, together with the analyte contained in it, from the interface to a flowmeter chamber via a liquid conduit.
In the flowmeter chamber, a measurement takes place to determine the concentration of the analyte. For this purpose, a detector arrangement is contained in the flowmeter chamber. The detector arrangement is advantageously designed as an amperometric detector arrangement. Amperometry is an electrochemical method based on a current measurement at constant potential. To this end, the “three electrodes method” known in the art and a potentiostat are preferably used.
To determine the glucose concentration in a fluid, the enzyme glucose oxidase, for example, is used to convert the glucose into hydrogen peroxide, among other things. The hydrogen peroxide formed serves as a detector molecule and is oxidized on a working electrode included in the detector arrangement, and the electric current thus generated is detected. For this purpose, a three-electrode measurement arrangement is used, consisting of a working electrode, a counterelectrode and a reference electrode, i.e., an electrode of constant electrochemical potential. The potential between working electrode and reference electrode, required for the desired reaction, is set by regulation of the current between working electrode and counter-electrode by the potentiostat.
The measurement carried out by the detector arrangement in the flowmeter chamber (for example, the measured current generated during the oxidation of the hydrogen peroxide on the working electrode) is evaluated by means of a signal processor contained in the arrangement. The signal processor determines, from the measured values of the detector arrangement, the concentration of the analyte in the body fluid. The fluid used up is preferably transported from the flowmeter chamber into a collecting container in the arrangement and is stored in said collecting container.
A malfunction of such an arrangement for determining the concentration of an analyte in a body fluid can have an effect on a large number of system parameters. The expression “system parameters” relates, in the context of the invention, to parameters that depend on the actual state of the arrangement and influence its functionality, in particular, the accuracy of the measured values determined by the arrangement. Examples of system parameters are the temperature of the stream of liquid flowing through the flowmeter chamber, the electrical voltage between the working electrode and counterelectrode and between the working electrode and reference electrode of a detector arrangement present in the flowmeter chamber, the flow rate of the perfusion liquid through the flowmeter chamber, pump parameters of a pump provided for pumping the perfusion liquid along the interface and through the flowmeter chamber, for example, the electric current of the pump and the speed of the pump, the battery voltage of a battery provided for supply of energy to the arrangement, and the active membrane exchange surface of a membrane provided as interface.
To identify a malfunction of the arrangement in good time and to avoid dangers resulting therefrom (for example, the administration of too high or too low a dose of insulin to a diabetic), the arrangement is monitored by means of the method according to the invention.
For monitoring the arrangement, a sensor system is provided in the arrangement. According to the invention, measured values of at least two correlated system parameters of the arrangement are measured by means of this sensor system. In this context, correlated system parameters are system parameters whose values are linked.
According to exemplary embodiments of the invention, the measured values of the at least two correlated system parameters are compared with limit values stored for each of the at least two parameters in a storage unit of the arrangement (preferably with comparison of two or three correlated system parameters). The limit values can define, for each system parameter, an upper limit and/or a lower limit. Conceivable comparison results for each system parameter are then: the measured value of the system parameter lies above the upper limit; the measured value lies below the upper limit; the measured value lies below the upper limit and above the lower limit; or the measured value lies above the lower limit, or the measured value lies below the lower limit.
The comparison of the measured values of the at least two correlated system parameters with the limit values yields a certain combination of comparison results. For example, the measured values of two correlated system parameters could yield the following combination of two comparison results: (1) the measured value of the first system parameter lies above a defined upper limit; and (2) the measured value of the second system parameter lies between a defined lower limit and a defined upper limit.
A specific state of the arrangement can be assigned to this combination of at least two comparison results. States that can be assigned to certain combinations of comparison results are states of the arrangement that affect its functionality. States can be assigned that are expressed in the combination of the measured system parameters. Possible states that can be assigned to the arrangement are preferably selected from the following group: that the correct function of the arrangement is ensured; that the efficiency of a component of the arrangement is reduced; that a certain defect of the arrangement is detected; or that an unknown defect of the arrangement exists.
The evidence of the measurements of the at least two correlated system parameters together permits a detection of the state of the arrangement, in particular of certain defects of the arrangement, which is not permitted by measurement of one system parameter alone. A reliable and continuous monitoring of the functionality of the arrangement is thus made possible by the method according to the invention.
The invention further relates to an arrangement for determining a concentration of an analyte in a body fluid, comprising an interface for taking the analyte from a body fluid into a stream of perfusion liquid in the arrangement, a liquid conduit for routing the stream of liquid from the interface to a flowmeter chamber, a transport device for transporting the stream of liquid through the liquid conduit from the interface to the flowmeter chamber, a detector arrangement located in the flowmeter chamber and used to carry out measurements to determine the concentration of the analyte, and a signal processor for calculating the concentration of the analyte from results of the measurement by the detector arrangement. The signal processor is preferably configured such that it can accept a reference value and compute it for calibration. The arrangement moreover may contain a sensor system for measurement of measured values of at least two (in particular, at least three) correlated system parameters, a storage unit, and means (in particular, a processor) for comparing the measured values with limit values stored for each of the system parameters in the storage unit, to obtain a combination of at least two (in particular, at least three) comparison results.
This arrangement can be used to carry out the method according to the invention. During use, the arrangement can be arranged outside the body of a living human or animal, except for the interface (for example, a microdialysis probe with semipermeable membrane) and, if appropriate, a small part of the liquid conduits extending to the interface and away from the interface. In particular, the monitoring method is performed exclusively outside the body. For this purpose, the sensors of the sensor system are arranged upstream of, downstream of and/or in the flowmeter chamber. The entire arrangement can be substantially miniaturized and constitutes a portable arrangement. Preferably, the sensor system comprises at least two sensors selected from the following group: electrical voltage sensor, electric current sensor, temperature sensor, flow rate sensor, revolution counter and concentration sensor. The concentration sensor is provided in particular for measuring the change in concentration of a substance exchange marker.
The concentration of the analyte can be determined by electrochemistry and amperometry, the measurement sensor comprising a polarizable electrode arrangement disposed in a flowmeter chamber. This electrode arrangement can consist, for example, of a working electrode made of platinum, a counterelectrode made of silver or platinum, and a reference electrode made of silver or silver/silver chloride.
According to one embodiment of the present invention, the signal processor, with defined combinations of comparison results, triggers at least one reaction of the arrangement, the at least one reaction being selected from the following group: display of a warning or problem report by a display unit of the arrangement, display of a recalibration prompt by the display unit, display, by the display unit, of a prompt to replace a component of the arrangement, switching off of the arrangement, output of an optical, acoustic or haptic alarm signal, regulation of at least one system parameter, influencing of values of a first system parameter by regulation of the values of a second system parameter correlated with the first system parameter, brief modification of a system parameter in order to eliminate a possible system error as a result of the combination of the comparison results.
The arrangement may comprise a display unit (for example, a liquid crystal display) which, in addition to warnings, can also display, for example, concentration values determined by the arrangement, or user menus from which a user is able to select user menu items, for example, by means of a keypad or other form of operating unit. With certain combinations of comparison results, the display unit can display warnings which, for example, warn a user of a defect of the arrangement or of resulting incorrect determination of a concentration value. For example, in the case of the following combination of comparison results: a) the measured value of the countervoltage (first system parameter) between counterelectrode and working electrode lies outside a range defined for this system parameter by an upper limit and a lower limit; b) the temperature of the stream of liquid (second system parameter correlated with the first system parameter) lies below a defined upper limit and above a defined lower limit; and c) the flow rate through the flowmeter chamber (third system parameter correlated with the first system parameter) lies below a defined upper limit and above a defined lower limit the display unit preferably displays a warning of a system error.
Moreover, with defined combinations of comparison results (in particular, those combinations pointing to a defect of the arrangement), the arrangement can output an optical alarm signal (for example, flashing of an LED), an acoustic alarm signal (for example, a warning tone) and/or a haptic alarm signal (for example, vibration of a component of the arrangement).
Another possible reaction of the arrangement to certain combinations of comparison results is the display, by the display unit, of a recalibration prompt. A recalibration can be carried out by directly measuring the concentration of the analyte in a collected sample of the body fluid and inputting this directly measured concentration value into the arrangement as a calibration value. Such a calibration is necessary, for example, if a defective state of the arrangement, which leads to an inadmissibly high measurement error, cannot be converted, by regulation of a system parameter, to a fault-free state that results in an admissibly high measurement error. Another possible reaction of the arrangement to certain combinations of comparison results is the display, by the display device, of a prompt to replace a component of the arrangement. For example, the user can be prompted to replace a battery.
Furthermore, the reaction to a defined combination of comparison results can be the regulation of a system parameter and/or the influencing of values of a first system parameter by regulation of the values of a second system parameter correlated with the first system parameter. For this purpose, regulating means are provided in the arrangement according to the invention. For example, the flow rate lying below the limit value can be regulated with the aid of the pump speed. Unsuccessful regulation results in a changed sensitivity of the current/concentration curve, such that, for example, a recalibration prompt is made.
Moreover, the signal processor can in certain cases cause the arrangement to switch off. For example, the signal processor can cause the arrangement to switch off if, after a temporary increase in the pumping rate, the mean flow rate measured over one hour falls below the stored limit value for the flow rate.
Another possible reaction of the arrangement to certain combinations of comparison results is a brief modification of a system parameter in order to eliminate a possible system error on account of the combination of the comparison results. For example, in the following combination of comparison results a) the measured value of the flow rate lies below a defined lower limit, b) the measured value of the battery voltage lies above a defined lower limit, and c) the measured value of a pump variable (for example, the speed of the pump) is below a defined upper limit, the pump variable (for example, the speed of the pump) can be increased briefly (for a defined time interval Δt), in order to flush away a flow obstruction possibly present in the conduits for the perfusion liquid. After the time interval has elapsed, the pump variable is lowered again, and a flow rate measured value is detected again and compared with the limit values defined for the flow rate.
In a method according to one embodiment of the invention, the sensor system preferably carries out measurements for the determination of at least two system parameters selected from the following group: temperature of the stream of liquid, electrical voltage between at least two electrodes along which the stream of liquid flows in the flowmeter chamber, time change of an electric current in relation to the time change of an electrical voltage with reference to at least two electrodes arranged in the flowmeter chamber, system variable of a transport device which is contained in the arrangement and which serves to transport the stream of liquid, battery voltage of at least one battery provided for energy supply in the arrangement, flow rate of the stream of liquid through the flowmeter chamber, and concentration of a marker.
The temperature of the stream of liquid can, for example, be measured directly by means of a temperature sensor which is positioned in the stream of liquid directly upstream of, in or directly downstream of the flowmeter chamber. However, it can also be recorded indirectly by a temperature measurement, by means of the temperature sensor, in which the temperature sensor measures the temperature of a structural part that is in direct or indirect contact with the stream of liquid. The electrochemical reaction taking place in an electrochemical flowmeter chamber for determination of the concentration of analytes is dependent on the temperature of the perfusion liquid (dialysate) in the flowmeter chamber, among other reasons because of the temperature dependency of the substance transport of analytes, reactants and reaction products from and to the electrode and the rate constants of the reaction itself. Therefore, if the temperature dependency of the measurement signal is known, it is possible, for example, on the one hand, to measure the temperature and to compensate mathematically for temperature fluctuations that occur, or, on the other hand, to minimize the temperature fluctuations by thermostating.
The electrical voltage between a counterelectrode and a working electrode (countervoltage) and/or between a reference electrode and a working electrode (cell voltage) can be determined, the counterelectrode, reference electrode and working electrode being provided for measuring the concentration of an analyte (for example, glucose). The cell voltage applied for the electrochemical reaction of the analyte is to be selected such that the measured current of the electrochemical reaction can be attributed as far as possible to the reaction of the analyte on the working electrode, i.e., that the reaction can be kept as free of interference as possible. For this purpose, it is necessary for the cell voltage to be maintained as constant as possible during the operation of the arrangement.
A transport device contained in the arrangement, and used to transport the perfusion liquid, is, for example, a pump that can be designed as a diaphragm pump (e.g., with piezoelectric drive), a piston pump (e.g., syringe pump), a dynamic pump (e.g., hydrodynamic or electro-osmotic pump) or as a hose pump. System variables of a pump are, for example, the electric current of the pump or the speed of the pump.
The at least one battery (or one accumulator) provided in the arrangement is used, for example, for supply of energy to an electrically operated pump, provided as transport device for the perfusion liquid, to a display unit, to a signal processor and to other components of the arrangement according to the invention.
To determine the flow rate of the stream of liquid through the flowmeter chamber, a flow rate sensor can be provided which is positioned, for example, downstream from the flowmeter chamber. The cross-membrane diffusive transport of substance in a (microdialysis) catheter is subject to a nonlinear dependency of the flow rate. Moreover, in an amperometric flowmeter chamber, a sensor signal dependent on flow rate can be established at constant analyte concentration. Finally, the flow rate has a direct effect on the time delay between the enrichment of the analyte in the perfusate and the measurement of the analyte concentration in the ex vivo flowmeter chamber (dead time). In view of these relationships, it is desirable for the system flow rate to be maintained as constant as possible. Within the technically acceptable tolerances of the system flow rate, the system flow rate is also to be selected such that a slight change in the system flow rate results in only slight changes of the measurement signal.
Moreover, the concentration of a marker in the stream of liquid can be determined in order to indicate the cross-membrane diffusive transport of substance at the interface of the arrangement (if a membrane is present). For a given perfusion liquid and temperature, the cross-membrane diffusive flux is dependent on the flow rate through a conduit (catheter) along the membrane and on the membrane exchange surface. The variation of the membrane exchange surface in vivo can be determined by determining the concentration of an endogenous marker, for example, sodium ions, present at an almost constant concentration. The cross-membrane diffusive flux of the analyte can be mathematically determined from this such that, for example, the flow rate can be adjusted in order to increase the diffusive flux.
Two correlated system parameters within the meaning of the present invention are in particular: a) the flow rate and the battery voltage (since, when the battery voltage drops, the capacity of the pump and thus the flow rate drop); b) the flow rate and a system variable of the transport device (since a system variable of the transport device directly influences the flow rate); c) the battery voltage and a system variable of the transport device (see comments for a) and b); d) the countervoltage and the temperature of the perfusion liquid (as the temperature increases, the turnover increases and, consequently, the countervoltage required to obtain a constant cell voltage increases); e) the countervoltage and the flow rate (as the flow rate increases, the electrochemical turnover per unit of time in the flowmeter chamber drops and the countervoltage therefore also drops); and f) the ratio of the time change of the electric measured current in the flowmeter chamber to the time change of the counter voltage and the flow rate (when the ratio lies below a certain limit value, there is a suspicion of the working electrode being coated with particles or an air bubble, which in turn has a negative impact on the flow rate).
According to an exemplary embodiment of the present invention, when carrying out the monitoring method according to the invention, a countervoltage between a counterelectrode, arranged in the flowmeter chamber, and a working electrode, a temperature of the stream of liquid, and a flow rate of the stream of liquid through the flowmeter chamber, are in each case compared by the signal processor with limit values stored in the storage unit.
According to a preferred embodiment of the present invention, when carrying out the monitoring method according to the invention, a flow rate of the stream of liquid through the flowmeter chamber, a battery voltage of a battery contained in the arrangement, and a system variable of a transport device contained in the arrangement and used to transport the stream of (perfusion) liquid, are in each case compared by the signal processor with limit values stored in the storage unit.
Values of at least one system variable measured by the sensor system can be taken into account in the determination of the concentration of the analyte. For example, the temperature of the stream of liquid can be measured by means of a temperature sensor, and a compensation value can then be determined from the measured temperature value. The temperature dependency of the electrode signal for determination of the concentration of the analyte can then be mathematically eliminated by means of the concentration value. Various possible ways of determining the compensation value are known in the prior art.
According to an exemplary embodiment of the present invention, at least two correlated system parameters are continuously monitored by the sensor system, while the determination of the concentration of the analyte typically takes place continuously. The measurement to determine the concentration of the analyte particularly preferably takes place with a defined measurement frequency, and the determination of the measured values of the at least two correlated system parameters also takes place with this defined measurement frequency. Measured values that are used to determine the concentration of the analyte can thus be attributed directly to values of the system parameters.
According to an exemplary embodiment, the method according to the invention is used to monitor an arrangement for determining the concentration of glucose in a body fluid, particularly in blood, of a live human. This arrangement can be used to determine the concentration of glucose in a body fluid of a live human.
BRIEF DESCRIPTION OF THE DRAWINGS
The above-mentioned aspects of the present invention and the manner of obtaining them will become more apparent and the invention itself will be better understood by reference to the following description of the embodiments of the invention, taken in conjunction with the accompanying drawing, wherein:
FIG. 1 shows a schematic representation of an arrangement according to the invention,
FIG. 2 shows a flow chart of a first embodiment of a monitoring method according to the invention, and
FIG. 3 shows a flow chart of a second embodiment of a monitoring method according to the invention.
DETAILED DESCRIPTION
The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention.
FIG. 1 is a schematic representation of the components of an arrangement according to the invention for determination of a concentration of an analyte in a body fluid. The arrangement comprises an interface 1 , for example, a microdialysis probe, via which an analyte (for example, glucose) from a body fluid (for example, interstitial fluid) can pass into a stream of liquid 2 in the arrangement (sample collection). The perfusion liquid is pumped from a reservoir 3 through a first liquid conduit 4 to the interface 1 and from there through a second liquid conduit 5 , a flowmeter chamber 10 and a third liquid conduit 6 into a collecting container 8 . A transport device 9 is provided for pumping the liquid. In the flowmeter chamber 10 there is a detector arrangement 7 (for example, a three-electrodes system containing a reference electrode, a working electrode and a counterelectrode with a potentiostat), which is used to carry out measurements for determining the concentration of the analyte. In the area of the flowmeter chamber 10 , there is a sensor system 11 , which is used to measure values of at least two correlated system parameters. The sensor system 11 and the detector arrangement 7 are connected to a signal processor 12 . From the results of the measurements by the detector arrangement 7 , the signal processor 12 calculates (if appropriate taking into account a calibration value) the concentration of the analyte. The relationships between the measurement signal, the concentration of the analyte in the stream of liquid 2 , the concentration of the analyte in the body fluid with which the interface 1 is in contact (for example, interstitial fluid) and, if appropriate, the concentration of the analyte in another body fluid (for example, blood) are known in the prior art and are stored in the signal processor 12 , preferably in the form of calculation rules.
The signal processor 12 is connected to a memory 13 in which, for example, measured or calculated values can be stored. Moreover, a further storage unit 14 can be provided which contains reference values for comparison with the measured values of the sensor system 11 . The reference values stored in the further storage unit 14 can be limit values for the at least two determined system parameters, for which purpose the memory 13 can also be used. The signal processor 12 serves as a means for comparing the actual values of the at least two correlated system parameters with these limit values stored in the storage unit 14 . This in each case yields an actual combination of at least two comparison results. With defined combinations of comparison results, the signal processor 12 triggers a reaction of the arrangement. The reaction, for example, involves a display unit 15 displaying a warning (for example, of a heightened measurement error of the detector arrangement 7 ), a problem report, a recalibration prompt, or a prompt to replace a component of the arrangement. By way of an interface 16 (for example, a keypad), a user can, for example, adjust the settings or functions of the arrangement or input a recalibration value. Other possible reactions to an actual combination of at least two comparison results can be the triggering of an alarm tone generator 17 , which emits an acoustic alarm signal. Furthermore, a regulator 18 can be activated, for example, for regulating a system parameter such as the cell voltage or the flow rate. Such a regulator has the advantage that the arrangement can operate over a long period of time without intervention by the user.
FIG. 2 shows a flow chart of a first embodiment of a monitoring method according to the invention.
This monitoring method is used to monitor the sensor voltages and currents of an amperometric detector arrangement. The cell voltage (polarization voltage) between the working electrode and the reference electrode is monitored by a comparison 19 of mean cell voltage values Ū pol , determined from measured values of a voltage sensor of the sensor system, with limit values Ū polmin and Ū polmax . If the cell voltage lies outside the range set by the limit values (comparison result n), it must be assumed that there is a problem with the arrangement or with the coupling between arrangement and voltage sensor. Consequently, an alarm is triggered/a warning report displayed 20 in order to prompt a trained user to eliminate the problem.
If the comparison 19 reveals that the cell voltage values lie within the range set by the limit values (comparison result y), the battery voltage U BATT is checked. The battery voltage measured by a voltage sensor of the sensor system is compared with a lower limit value U BATT,min (reference number 21 ). If the battery voltage lies below the limit value (comparison result n), an alarm is triggered/a report displayed 22 , in order to prompt the user to change the battery.
If the comparison 21 reveals that the battery voltage values lie above the lower limit value (comparison result y), the countervoltage U CE between the counterelectrode and working electrode of the detector arrangement is checked. For this purpose, the countervoltage measured by a voltage sensor of the sensor system is compared with lower and upper limit values U CEmin and U CEmax (reference number 23 ). If the countervoltage lies outside the range defined by the limit values (comparison result n), then the temperature T correlated with the countervoltage is checked by a comparison 24 with lower and upper limit values T min and T max . If the temperature measured by a temperature sensor of the sensor system lies outside the range set by the limit values (comparison result n), then the combination of the comparison results for countervoltage and temperature (n, n) reveals that a system error is present and an alarm 25 should be triggered.
If the temperature lies within the range defined by the limit values (comparison result y), then, according to the invention, the mean flow rate F correlated with the countervoltage is checked by comparison 26 with limit values F min and F max .
If the mean flow rate F determined from measured values of a flow rate sensor of the sensor system lies within the range set by the limit values (comparison result y), then the combination of the comparison results for countervoltage, temperature and mean flow rate (n, y, y) reveals that a system error is present and an alarm 27 should be triggered.
If the mean flow rate F lies outside the range set by the limit values (comparison result n), then the combination of the comparison results for counter-voltage, temperature and mean flow rate (n, y, n) reveals that a flow obstruction is possibly leading to at least partial coating of the counterelectrode. Therefore, in order to eliminate this problem, a pump variable P (for example, the electric current of the pump) is increased by ΔP (reference number 28 ) for a time interval Δt 5 in order to increase the flow rate. After Δt 5 has elapsed (reference number 29 ), the pump variable is lowered again by ΔP (reference number 30 ). Then, after a time interval Δt 6 has elapsed (reference number 31 ), a comparison 32 of the countervoltage U CE with the limit values U CEmin and U CEmax is again carried out.
If the comparison 32 reveals that the countervoltage still lies outside the range defined by the limit values (comparison result n), an alarm 27 is triggered as a reaction. If it now lies within the range (comparison result y), then the ratio of the time change of the measured current dI/dt to the time change of the countervoltage dU CE /dt is next checked by a comparison 33 with lower and upper limit values. This comparison is also carried out if the original comparison 23 of the countervoltage has delivered the comparison result y (countervoltage lying within the limit values). If the ratio of the time change of the measured current to the time change of the counter-voltage lies between the limit values (comparison result y), then the method is carried out again, starting with the comparison 19 of the cell voltage. If the ratio lies outside the range set by the limit values, a distinction is made between two cases 34 , 35 . In the first case 34 , the lower limit value is undershot. As a reaction to this, the method, as described above, is continued by checking the flow rate (comparison 26 ). In the second case 35 , the upper limit value is exceeded and, as a reaction, the arrangement is switched off 36 , since a short circuit is suspected.
FIG. 2 is shown enlarged, with further inscriptions, in both subsidiary FIGS. 2 a and 2 b.
FIG. 3 shows a flow chart of a second embodiment of a monitoring method according to the invention.
The embodiments according to FIGS. 2 and 3 can be implemented singly or in combination in an arrangement according to the invention (for example, according to FIG. 1 ). The monitoring method according to FIG. 3 is used to monitor the flow rate in an arrangement for determining the concentration of an analyte.
The constancy of the flow rate of a stream of liquid is an important condition for a constant dead time, a constant substance exchange via the interface (for example, membrane wall of a catheter) and the concentration measurement in the flowmeter chamber (for example, electrochemical measurement). The mean flow rate is therefore preferably monitored by a comparison 37 of a flow rate F, determined from measured values of a flow rate sensor, with lower and upper limit values F min and F max . If the flow rate lies within the range defined by the limit values (comparison result y), then the pump variable P correlated with the flow rate is checked by a comparison 38 with lower and upper limit values P min and P max in order to test the transport device (pump). In the case of a pump variable lying between the limit values (comparison result y), the combination of the comparison results of flow rate and pump variables (y, y) reveals that the transport device (pump) is functioning correctly. The comparison 37 of the actual flow rate with the limit values is then repeated after a time interval Δt 4 (reference number 39 ).
In the case of a pump variable lying outside the range defined by the limit values in the comparison 38 (comparison result n) (for example, if the current consumption of the pump is too high), an alarm is triggered/a report displayed 40 , in order to prompt a user to check the pump.
If the comparison 37 of the mean flow rate reveals that it lies outside the range set by the limit values (comparison result n), then the battery voltage U BATT correlated with the mean flow rate is checked. It is compared for this purpose with a lower limit value U BATT,min (reference number 41 ). If the battery voltage drops below the limit value (comparison result n), then an alarm or a message 42 prompts the user to replace the battery or accumulator. If the battery voltage lies above the limit value (comparison result y), then a distinction is made between two cases 43 , 44 for this combination of comparison results of flow rate and battery voltage (n, y).
In the first case 43 , the mean flow rate lies below the lower limit value F min . In this case, the pump variable P correlated with the flow rate (for example, the pump current or speed) is checked by comparison 45 with limit values P min and P max . If the pump variable lies outside the range set by the limit values (comparison result n), then the combination of the comparison results for mean flow rate, battery voltage and pump variable (n, y, n) reveals that there is a defect of the transport device (pump), such that an alarm is triggered/a report displayed 46 in order to prompt the user to check the pump.
If the pump variable lies within the range defined by the limit values (comparison result y in comparison 45 ), then the combination of the comparison results for mean flow rate, battery voltage and pump variables (n, y, y) reveals that a bubble or a particle may be forming a temporary flow obstruction. In order to eliminate this problem, the pump variable P (for example, the pump current) is increased by ΔP (reference number 48 ) for a time interval Δt 1 in order to increase the flow rate. After Δt 1 has elapsed (reference number 49 ), a comparison 50 of the mean flow rate with the limit values F min and F max is carried out again.
If the comparison 50 reveals that the mean flow rate still lies outside the range defined by the limit values (comparison result n), an alarm is triggered as a reaction or a warning report is displayed (reference number 51 ). If it lies within the range (comparison result y), then the pump variable is lowered again by ΔP (reference number 53 ) after a time interval Δt 2 has elapsed (reference number 52 ). The mean flow rate is then checked again (comparison 37 ) after a defined time interval Δt 3 has elapsed (reference number 54 ).
In the second case 44 , the mean flow rate lies above the upper limit value F max . In this case, an alarm 47 is triggered directly in order to warn of a system error.
Thus, embodiments of the method for monitoring an arrangement for determining the concentration of an analyte in a body fluid are disclosed. One skilled in the art will appreciate that the teachings can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation, and the invention is only limited by the claims that follow. | The invention relates to a method for monitoring an arrangement for determining a concentration of an analyte in a body fluid. The determination of the concentration of the analyte by means of the arrangement involves a procedure in which the analyte from the body fluid passes through an interface and is transported in a stream of liquid into a flowmeter chamber, in which a measurement is carried out to determine the concentration of the analyte. The evaluation of the measurement takes place in a signal processor. The monitoring of the arrangement comprises the following steps: measurement of measured values of at least two correlated system parameters of the arrangement by means of a sensor system, and comparison of the measured values with limit values stored for each of the system parameters in a storage unit, to obtain a combination of at least two comparison results. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit to U.S. Provisional Application No. 60/364,100 filed on Mar. 15, 2002.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention pertains to the art of refrigerators and, more particularly, to a support arrangement for a pull-out freezer drawer.
[0004] 2. Discussion of the Prior Art
[0005] There exist various styles of refrigerators on the market. Most common are side-by-side, top mount, and bottom mount models. In a side-by-side model, fresh food and freezer compartments are arranged laterally adjacent one another. A top mount refrigerator includes an upper freezer compartment and a lower fresh food compartment. Finally, bottom mount models have the fresh food compartment located above the freezer compartment.
[0006] In bottom mount models, it is known to employ both pivoting freezer doors and freezer doors which slide between open and closed positions. In a bottom mount style refrigerator including either a pivoting or sliding door, it is known to employ one or more sliding baskets to store food items within the freezer compartment. More specifically, in connection with a bottom mount refrigerator including a pivoting freezer door, it is known to thermoform a freezer compartment defining liner with integral side rails upon which one or more baskets can be directly slidably supported. In bottom mount refrigerators employing sliding doors, it is common to mount elongated support members to the opposing side walls of the freezer compartment through the use of mechanical fasteners, and then to support one or more baskets, either directly or indirectly, upon the support members. Typically, in this case, at least the support for one of the baskets is also connected to the door such that, as the door is slid relative to a cabinet of the refrigerator, the basket shifts into and out of the freezer compartment. Most commonly, these types of bottom mount refrigerators employ metal liners into which mechanical fasteners in the form of screws are secured to attach the support members.
[0007] Given construction and assembly variations between these different types of bottom mount refrigerators, completely different liners are required depending on whether a pivoting or sliding door arrangement is desired. Therefore, it is not possible to simply change a bottom mount refrigerator designed for use with a pivoting door to employ a sliding door arrangement. Based thereon, it would be beneficial to provide a supplemental adapter assembly which would enable a bottom mount refrigerator cabinet to be used with either pivoting or sliding doors and their associated basket arrangements.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to a support assembly which is adapted to be fitted between rail structure formed in a thermoformed or injection molded freezer compartment liner of a bottom mount refrigerator in order to enable the refrigerator to be used with a slidably mounted freezer door/storage drawer combination. More specifically, a freezer compartment liner, formed with integral side rail structure that can directly, slidably support storage drawers or baskets, is adapted to receive side support adapters that enable the liner to be used in combination with a slidable freezer door which is interconnected to extensible slide structure for one or more drawers or baskets.
[0009] In accordance with the most preferred embodiment of the invention, each side support adapter includes upper and lower basket support structure. The lower basket support structure defines a channel which is adapted to snap-fittingly receive a drawer support slide member that is indirectly attached to a slidable freezer door of the refrigerator. The upper basket support structure is defined by a ledge on each of the side adapters which provides a support surface for an upper basket to slide independently of the lower basket. Projecting from a rear of each side support adapter are multiple lugs which are received within grooves or recesses defined in the liner and rest on substantially horizontal ledge portions through which vertical loads are transferred to the overall cabinet of the refrigerator. Each side adapter is preferably tapered from front to back to offset a tapering of the thermoformed or injection molded liner. In this manner, the opposing side adapters extend substantially parallel to each other. Mechanical fasteners are used to secure the side support adapters in place.
[0010] Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a partial exploded view of a bottom mount style refrigerator incorporating the freezer drawer support assembly of the invention;
[0012] FIG. 2 is an enlarged view of a side wall portion of a liner provided in the refrigerator of FIG. 1 , with a side adapter of the freezer drawer support assembly shown adjacent thereto prior to mounting;
[0013] FIG. 3 is a rear view of the side adapter of the freezer drawer support assembly of the invention;
[0014] FIG. 4 is a partial view of the side wall portion of FIG. 2 , with the side adapter of the freezer drawer support assembly of the invention secured thereto; and
[0015] FIG. 5 is a cross-sectional view of the overall drawer support assembly of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] With initial reference to FIG. 1 , a refrigerator incorporating the invention is generally indicated at 2 . Refrigerator 2 includes a cabinet shell 6 to which is attached a fresh food compartment door 10 . At this point, it should be readily recognized that refrigerator 2 constitutes a bottom mount style refrigerator wherein fresh food compartment door 10 is adapted to seal off an upper fresh food compartment defined within cabinet shell 6 . In a manner known in the art, fresh food compartment door 10 is preferably, pivotally mounted about a vertical axis to cabinet shell 6 through upper and lower hinges (not shown). Refrigerator 2 also includes a lower freezer compartment 13 which is defined by a liner 15 . Freezer compartment 13 is adapted to be sealed by means of a freezer door 18 having an associated handle 19 . In accordance with the present invention, freezer door 18 is adapted to slide towards and away from cabinet shell 6 through the use of a slide assembly generally indicated at 22 in order to selective access or seal freezer compartment 13 .
[0017] As shown in this figure, slide assembly 22 generally includes a pair of opposing basket support plates 28 and 29 which are adapted to be fixedly secured to a rear portion of freezer door 18 through suitable brackets and fasteners (not shown). Basket support plates 28 and 29 respectively mate with a pair of door support plates 32 and 33 which, in turn, interconnect basket support plates 28 and 29 to respective extensible drawer slides 36 and 37 . As will be detailed more fully below, drawer slides 36 and 37 are interconnected to liner 15 of freezer compartment 13 through respective side adapters 40 and 41 . The present invention is particularly concerned with the inclusion, construction, and mounting of each side adapter 40 , 41 as will be detailed below. FIG. 1 also illustrates a lower basket 44 which is adapted to be carried by basket support plates 28 and 29 so as to be shiftable into and out of freezer compartment 13 with the movement of freezer door 18 .
[0018] FIG. 2 illustrates details of liner 15 and side adapter 40 . In general, liner 15 includes a flat bottom portion 52 , an inclined bottom portion 53 , a rear wall 54 , and opposing side walls 55 . Each side wall 55 is shown to include an aft section 57 and a frontal section 58 . In the preferred embodiment shown, aft and frontal sections 57 and 58 extend in different planes and are interconnected by an offset section 59 . In any event, frontal section 58 leads to a frontal edge generally indicated at 61 .
[0019] Formed in side wall 55 , from offset section 59 to directly adjacent rear wall 54 , is an elongated upper groove or recess 66 , as well as a lower groove or recess 67 . In general, upper and lower grooves 66 and 67 are formed in each side wall 55 in order to enable upper and lower baskets (not shown) to be slideably mounted within liner 15 when refrigerator 2 is utilized in combination with a pivoting freezer door. In accordance with the present invention, side adapters 40 and 41 are provided to mate with the structure of upper and lower grooves 66 and 67 in order to enable liner 15 to be utilized in connection with slideable freezer door 18 and slide assembly 22 .
[0020] Based on the above, it should be recognized that, although the actual configuration of upper and lower grooves 66 and 67 can take various forms, the preferred form shown in FIG. 2 is known in the art for use in connection with a bottom mount refrigerator employing a pivotable freezer door and upper and lower freezer baskets. In any event, the actual configuration shown for upper and lower grooves 66 and 67 are perhaps best defined by the supporting structure associated therewith. Therefore, due to the inclusion of lower groove 67 , side wall 55 is formed with a lower frontal ledge portion 73 , an intermediate, lower ledge portion 74 , and a lower, rear ledge portion 75 . In addition, due to the presence of upper groove 66 , side wall 55 defines an upper frontal ledge portion 80 , an upper intermediate ledge portion 81 , and an upper, rear ledge portion 82 . Again, this structure enables an upper rim of a lower basket, and a lower rim of an upper basket to extend between the side walls 55 of liner 15 and be slideably mounted for movement into and out of freezer compartment 13 . However, in accordance with the present invention, side adapters 40 and 41 are mounted utilizing the existing structure of side walls 55 to accommodate the overall slide assembly 22 in accordance with the invention.
[0021] Reference will now be made to FIGS. 2-4 in describing the construction of each side adapter 40 , 41 of the present invention. At this initial stage, it should be noted that side adapters 40 and 41 are essentially mirror images of one another, such that the common structure will be described with respect to side adapter 40 shown in FIGS. 2 and 4 and side adapter 41 as shown in FIG. 3 . In general, each side adapter 40 , 41 includes a frontal section 90 and a rear section 91 . As it is important to enable freezer door 18 to shift straight away from cabinet shell 6 and return to a position which establishes a proper seal, each side adapter 40 , 41 is specifically constructed to accommodate for any divergence between side walls 55 of liner 15 in order that side adapters 40 and 41 define parallel paths for extensible drawer slides 36 and 37 . Therefore, in accordance with the most preferred form of the invention, each side adapter 40 , 41 slightly tapers from frontal section 90 to rear section 91 as indicated in these figures.
[0022] In any event, each side adapter 40 , 41 is shown to include an upstanding wall 95 which follows the contour of side wall 55 from offset section 59 through aft section 57 , with upstanding wall 95 leading to an upper ledge 96 . In turn, upper ledge 96 leads to an upper wall 97 behind which is defined an elongated recess indicated at 98 in FIG. 3 . Preferably defined within recess 98 is a first boss 101 provided with a hole 102 , as well as a second boss 103 provided with a corresponding hole 104 . Below upper wall 97 is provided a recessed, intermediate wall 105 that is shown to include an upper row of slots 107 and a lower row of slots 108 . Located forward of recess 98 is a third boss 111 having an associated hole 112 . As will be detailed more fully below, first, second and third bosses 101 , 103 and 111 are adapted to receive mechanical fasteners through respective holes 102 , 104 and 112 in mounting side adapters 40 and 41 to liner 15 . For reinforcement purposes, a plurality of ribs, such as those indicated at 115 - 117 are provided as structural reinforcements around bosses 101 , 103 and 111 respectively. An additional structural reinforcement 121 is preferably provided forward of third boss 111 as well.
[0023] In the most preferred form of the invention, each side adapter 40 , 41 is injection molded of plastic. Most preferably, when forming each side adapter 40 , 41 , intermediate wall 105 is integrally formed with an upper frontal lug 127 and a rear lug 132 . In the most preferred form of the invention, each of upper frontal lug 127 and rear 132 is generally boxed-shaped, with at least upper frontal lug 127 being provided with various cross supports 135 . Also formed along intermediate wall 105 is a pair of central bosses 139 and 140 , as well as a cantilevered member 143 .
[0024] Below intermediate wall 105 , and preferably beneath upper frontal lug 127 , is a lower frontal lug 147 . In accordance with the embodiment shown, lower frontal lug 147 includes a main plate portion 148 from which extend a plurality of ribs 149 . Also arranged below intermediate wall 105 is a lower wall 151 which is shown to be formed with a fourth boss 153 .
[0025] As shown in FIGS. 2-4 , upper ledge 96 has projecting therefrom an upstanding stop 155 . Upstanding stop 155 is spaced from upstanding wall 95 by upper ledge 96 . Adjacent upstanding stop 155 , upper ledge 96 leads to a lateral section 157 of a respective side adapter 40 , 41 . Lateral section 157 forms part of frontal section 90 and leads to a forwardly sloping section 160 , a front face section 163 , a rearwardly sloping section 165 , and a short bottom section 167 . With this overall construction, each side adapter 40 , 41 defines a channel 176 that extends along intermediate wall 105 and which defines a lower ledge 178 . Channel 176 is also defined, at least laterally, by an upper row of teeth members 179 and a lower row of teeth members 180 . As clearly shown in these figures, cantilevered member 143 is exposed to channel 176 and is provided at a rear end thereof with a wedge section 188 which projects into channel 176 .
[0026] During assembly of refrigerator 2 , liner 15 is preferably thermoformed with upper and lower grooves 66 and 67 . With this construction, liner 15 can be used to directly, slideably support upper and lower freezer baskets when refrigerator 2 is used in combination with a pivoting freezer door. However, in accordance with the present invention wherein freezer door 15 is slideable relative to cabinet shell 6 , each side wall 55 has mounted thereon a respective side adapter 40 , 41 . In mounting each side adapter 40 , 41 , upper frontal lug 127 is positioned to rest upon upper frontal ledge portion 80 , rear lug 132 is positioned upon upper rear ledge portion 82 , and lower frontal lug 147 sets upon lower frontal ledge portion 73 . The resting of upper frontal lug 127 and lower frontal lug 147 in this manner is seen to be clearly illustrated in FIG. 5 .
[0027] Due to the construction of each side adapter 40 , 41 , frontal section 90 is made to conform to frontal section 58 , as well as offset section 59 , of a respective side wall 55 . Correspondingly, rear section 91 conforms to aft section 57 of side wall 55 . Once supported in this fashion, mechanical fasteners (not shown) are extended through holes 102 , 104 and 112 in bosses 101 , 103 and 111 in order to fixedly secure each side adapter 40 , 41 to a respective side wall 55 . Most preferably, refrigerator 2 is provided with mounting structure, such as in the form of plates, which are arranged behind liner 15 at the location of at least bosses 101 , 103 and 111 , with this mounting structure being rigidly maintained in a desired position upon the curing of foamed insulation injected between cabinet shell 6 and liner 15 in a manner known in the art. Therefore, the threaded fasteners associated with bosses 101 , 103 and 111 extend not only through liner 15 but also into additional mounting structure to secure each side adapter 40 , 41 in place. If desired, an additional fastening point can be established at fourth boss 153 .
[0028] Once side adapters 40 and 41 are mounted in this fashion, each drawer slide 36 , 37 can be secured to a respective side adapter 40 , 41 within channel 176 . More specifically, each drawer slide 36 , 37 is slid upon a respective lower ledge 178 , between intermediate wall 105 and the upper and lower rows of teeth members 179 and 180 . As best shown in FIG. 5 , each drawer slide 36 , 37 preferably includes an outermost cabinet member 201 , an intermediate member 202 and a drawer member 203 . Interposed between cabinet member 201 and intermediate member 202 are respective ball bearings 206 . Similarly, ball bearings 207 are provided between intermediate member 202 and drawer member 203 .
[0029] In any event, each drawer slide 36 , 37 is adapted to be mounted within a respective channel 176 . As cabinet member 201 reaches cantilevered member 143 , the abutment with wedge section 188 will cause cantilever member 143 to deflect inward, thereby allowing at least a portion of cabinet member 201 to pass cantilever member 143 . Although not shown in these figures, cabinet member 201 preferably includes an aperture which becomes aligned with wedge section 188 upon full insertion of slide assembly 22 within channel 176 such that cantilevered member 143 will be caused to again deflect to the position shown in FIGS. 2 and 4 , thereby selectively retaining drawer slide 36 , 37 in position. Actually, there is preferably a rather snug fit between drawer member 201 and channel 176 as generally represented in FIG. 5 .
[0030] As also shown in this figure, drawer member 203 is fixedly secured to a respective door support plate 32 , 33 which, in turn, is interconnected to a respective basket support plate 28 , 29 . Since each basket support plate 28 , 29 is secured to freezer door 18 , when freezer door 18 is pulled away from cabinet shell 6 , basket support plates 28 and 29 and door support plates 32 and 33 will be drawn out of freezer compartment 13 with drawer member 203 . Drawer member 203 will be shifted relative to intermediate member 202 due to the arrangement of ball bearings 207 . When drawer member 203 reaches a fully extended position, then both drawer member 203 and intermediate member 202 will extend relative to cabinet shell 6 and cabinet member 201 . Eventually, extensible drawer slides 36 and 37 will achieve their maximum extended position, at which point at least basket 44 is fully exposed outside of freezer compartment 13 .
[0031] Based on the above description, it should be readily apparent that the inclusion of side adapters 40 and 41 not only enable the use of a common liner 15 on various model refrigerators, but accommodates the tapering of side walls 55 to assure that extensible drawer slides 36 and 37 will extend parallel to one another. The incorporation, structure and positioning of lugs 127 , 132 and 147 enable each side adapter 40 , 41 to nest in the existing geometry formed into liner 15 either through a thermoforming or injection molding process. Therefore, lugs 127 , 132 and 147 transfer vertical loads directly to the overall foamed refrigerator assembly which is considered to be extremely advantageous, as opposed to hanging side adapters 40 , 41 from liner 15 solely through the use of screws and anchors. The inclusion of cantilevered member 143 and wedge section 188 advantageously provides a snap feature for the mounting of a respective drawer slide 36 , 37 and prevents the drawer slide 36 , 37 from undesirably sliding forward. Upper ledge 96 on each side adapter 40 , 41 establishes a setting surface for an upper basket (not shown) which can slide independently of drawer slides 36 and 37 . This configuration is considered to allow a greater range of motion for an upper basket. When such an upper basket is employed, it should be noted that the basket can be drawn out to also rest upon an uppermost edge 210 of basket support plates 28 and 29 .
[0032] Although described with reference to a preferred embodiment of the invention, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, it should be readily apparent that side adapters 40 and 41 have been configured based on the preferred construction shown for side walls 55 of liner 15 . This configuration is currently used in connection with a freezer compartment 13 of approximately 33 inches wide. On more narrow models wherein only a single basket may be utilized, only a single groove may be provided in the liner. Therefore, the actual configuration of the side adapters and the number of lugs for supporting the same would correspondingly change. Of course, it is also known to produce refrigerator liners with inwardly projecting rails and a side adapter in accordance with the present invention could also be configured for use with this type of arrangement. Regardless, given that the invention is intended for use in connection with a slideable freezer door 18 , it is important to maintain the parallel relationship between the respective channels 176 and therefore side adapters 40 and 41 must be constructed in such a manner as to compensate for variations in the lateral dimensions of the freezer liner, such as in cases where the freezer liner tapers from front to rear. In any event, side adapters 40 and 41 can advantageously define support structure for multiple baskets and are integrally formed with lug structure which effectively transfers vertical loading. In general, the invention is only intended to be limited by the scope of the following claims. | A freezer drawer support assembly is provided for a refrigerator including an upper fresh food compartment and a lower freezer compartment having a rearwardly tapering liner. The support assembly includes a pair of side adapters which compensate for the tapering of the liner, while defining both channels for the attachment of extensible drawer slides, to which a freezer door and a slidable basket is attached, and ledges for slidably supporting another basket. Preferably, the side adapters mate with groove and ledge structure formed into the liner to enhance the transfer of weight from the baskets, while enabling a refrigerator liner designed to directly support one or more slidable baskets to indirectly support multiple baskets which can be slid relative to each other. | 5 |
RELATED APPLICATIONS
[0001] The present application is related to U.S. Pat. No. 6,968,194, entitled “METHOD AND SYSTEM FOR LOCATION FINDING IN A WIRELESS LOCAL AREA NETWORK” issued on Nov. 22, 2005; U.S. Pat. No. 6,963,289, entitled “WIRELESS LOCAL AREA NETWORK (WLAN) CHANNEL RADIO-FREQUENCY IDENTIFICATION (RFID) TAG SYSTEM AND METHOD THEREFOR”, issued on Nov. 8, 2005; and United States Patent Application entitled “ENHANCED AREA SEPARATION IN WIRELESS LOCATION SYSTEMS SYSTEM AND METHOD” filed on Aug. 8, 2006 and having Ser. No. 11/466,540. The above are all assigned to the same assignee and are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention relates generally to a Wireless Local Area Network (WLAN) and, more specifically, to a WLAN location system which provides the real time location of an asset as well as the exact room in which the asset is located at a given time with high reliability and accuracy.
BACKGROUND OF THE INVENTION
[0003] In many sites where a real time location system is installed, it is important not only to know the real time location of an asset but also the exact room number in which it is located at a given time with high reliability. This is specifically required in large building floor areas that are divided into many small rooms such as in hospital buildings.
[0004] A typical WLAN based Real Time Location System (RTLS) utilizes radio wave signals in order to calculate the device location. This is typically done RSSI (remote signal strength indication) or TOA (time of arrival) measurements of a radio signal that is transmitted by the tag. The signal is received by several location receivers or access points that are in different positions, and special geometrical and mathematical algorithms are implemented to calculate the device's location. Further elaboration of these systems and methods can be found in the above mentioned patent application.
[0005] Even though such systems today can reach high location accuracies (below 1-2 m), present systems have problems with providing the best solution for knowing the exact room location/number. This characteristic will be referred to as “room separation”. Therefore, an asset that is located in one room can appear by mistake on the other side of a wall, i.e. in the adjacent room. This happens due to the fact that radio signals can penetrate through walls and the system sometime is not “sensitive” to the existence of a wall.
[0006] The main challenges with respect to room separation are as follows: (1). Provide almost 100% room separation, tell the user the exact room location of an asset with very low probability of locating the asset in a wrong room, (2) Maintain the location capabilities and other advantages of the WLAN based real time location system, such as outdoor location, telemetry etc, and (3) Obtain the above with minimal additional cost per room.
[0007] A typical solution to “room separation” issues would be to use low frequency radio communication: A low frequency transmitter (sometime referred to as Exciter) is periodically transmitting a beacon signal which includes the room number information. The tag is triggered by the low frequency transmission, wakes up and transmits a WLAN message that reports the Exciter ID and-or room number to the system. The Exciter is positioned at the entrance to a room, so that it triggers every tag that gets into the room. In other scenarios, the Exciter is located on a wall inside a room, and tuned so that its radiation will be received in almost every position inside the room and only in the room. Further elaboration of these systems and methods can be found in the above mentioned patent application.
[0008] The above system solves the requirement # 2 , as it is fully integrated with the WLAN RTLS. However, it completely does not satisfy the requirement # 3 —it is difficult to obtain a relatively low cost solution per room due to the cost of an Exciter. Furthermore, it does not always provide 100% room separation (Requirement # 1 ) since: (a) it is sometimes very difficult to tune the Exciter to be received at each point in the room and only in one room; and (b) it is difficult to differentiate between entrance and exit events to a room, which complicates the overall system solution.
[0009] Using ultrasonic waves is another way to provide room separation, since they expand freely in empty space, but do not penetrate through walls. Existing real time location systems that utilize ultrasonic waves, include a transmitter in the tag and one or more ultrasonic receivers connected in a network and are attached to the walls or ceiling inside a room. The tag constantly transmits an ultrasonic signal and the receivers report the signal level and/or tag ID to the network, which identifies the room in which the tag transmits. Since the ultrasonic signals transmitted by the tag are received only by those receivers that are in the same room with it, it is rather easy to determine the exact room. Determining the exact location in a room is also possible but rather more difficult.
[0010] This system solves the Requirement # 1 , as it provides a good method to obtain almost perfect room separation. However, the ultrasonic wave system is an independent system which requires its own unique infrastructure, and hence it does not satisfy Requirement # 2 , and does not include all the benefits a user obtains from using his standard WLAN infrastructure for the location system. It further does not satisfy Requirement # 3 as it requires a unique infrastructure in addition to a WLAN infrastructure, which increases the total cost of the solution. In each room, a few receivers need to exist hence the total cost per room is also relatively high.
[0011] Therefore, a need existed to provide a system and method to overcome the above problem. The system and method allows for performing room separation using ultrasonic signals, as well as WLAN based location and services. The architectural way in which the two technologies are combined and integrated together enables answering all of the requirements for room separation mentioned above in a very efficient way.
SUMMARY OF THE INVENTION
[0012] In accordance with one embodiment of the present invention, a wireless location system is disclosed. The wireless location system is used for tracking and locating a wireless tag in a structure having defined areas that provides for differentiation between the defined areas. The wireless location system has at least one ultrasonic transmitter positioned in each of the defined areas for transmitting an ultrasonic signal having area identification and/or transmitter ID information. A plurality of wireless tags are provided wherein each wireless tag transmits the last area identifying information or the last transmitter ID received and accepted by the wireless tag in a tag message. A plurality of location receivers and/or WLAN Access Points is installed in the structure for receiving the tag message and for reporting the received message from the tag along with optional measured parameters to a common server. The server determines the location of each wireless tags in the structure also using the defined area or transmitter ID as reported by each wireless tag.
[0013] In accordance with another embodiment of the present invention a method for tracking and locating wireless tags in defined areas of a structure and that provides for differentiation between the defined areas is disclosed. The method comprises: providing location receivers and/or WLAN Access Points installed in the structure to locate wireless tags; installing at least one ultrasonic transmitter in each individual defined area; transmitting an ultrasonic signal by each of the at least one ultrasonic transmitter in each individual defined area, each ultrasonic signal confined to the individual defined area where transmitted, the ultrasonic signal having area identifying information and/or transmitter ID; receiving the ultrasonic signal having the area identifying information and/or transmitter ID by a wireless tag in coverage range of the at least one ultrasonic transmitter in the individual defined area; and transmitting a tag message by the wireless tag in coverage range, the tag message including a last identifying information (area identification and/or transmitter ID) received and accepted by the wireless tag and a wireless tag identification data.
[0014] In accordance with another embodiment of the present invention, a wireless tag is disclosed. The wireless tag has an ultrasonic receiver module for receiving an ultrasonic signal having area identification and/or transmitter ID information. A transmitter is provided for transmitting the area identification and/or transmitter ID information received and accepted by the wireless tag and an identification number of the wireless tag. A memory is provided for storing at least the identification numbers (area and/or transmitter ID). A micro processor is coupled to the memory, the ultrasonic receiver module, and the transmitter. A power supply is provided for supplying power to circuitry of the wireless tag.
[0015] The present invention is best understood by reference to the following detailed description when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a map having the system of the present invention;
[0017] FIG. 2 is a simplified block diagram showing the system of FIG. 1 ;
[0018] FIG. 3 is a simplified block diagram of a wireless tag used in the present invention; and
[0019] FIG. 4 is a simplified block diagram of an ultrasonic transmitter used in the present invention.
[0020] Common reference numerals are used throughout the drawings and detailed descriptions to indicate like elements.
DETAILED DESCRIPTION
[0021] Referring to the Figures, one embodiment of a wireless network 100 of the present invention will be disclosed. The network 100 is a wireless location system which provides the real time location of an asset as well as the exact room in which the asset is located at a given time with high reliability and accuracy.
[0022] The network 100 uses a standard wireless tag 102 . In FIG. 1 , six different tags 102 are shown. However, this is only shown as an example and should not limit the scope of the present invention. In accordance with one embodiment, the tag 102 is a WLAN based tag. However, the present invention can be implemented in tags 102 as well as in any standard wireless client operating in such networks. For the sake of simplicity, any reference to tags 102 in the application, applies also to WLAN mobile units or WLAN standard clients and vice versa.
[0023] The tag 102 is used in a wireless location system 104 . The wireless location system may be a WLAN based location system or the like. Other types of wireless location systems may be used without departing from the spirit and scope of the present invention. The description below will be drawn towards a WLAN based system. However, this should not be seen as to limit the scope of the present invention. As shown in FIG. 1 , the wireless location system 104 uses a plurality of location receivers and/or Access Points 110 located throughout Map A and able to receive messages transmitted by the tags 102 . As stated above, however, room differentiation is a problem. The location of each tag 100 is calculated by a server (not shown in FIG. 1 ) connected to those location receivers and/or Access Points 102 based on the information reported by these location receivers and/or Access Points 102 for each of the tags 100 . As previously mentioned, when this location is calculated only based on parameters measured on RF radio signals, there is some probability that it will be in the wrong room.
[0024] To overcome the issue of room differentiation, each tag 102 is integrated with an ultrasonic receiver module 106 (See FIG. 3 ). Once triggered by an ultrasonic signal (US) transmitted by an US transmitter 108 which includes a room and/or transmitter ID number, the tag 102 transmits a WLAN radio message (RM) to the network 100 which includes the room and/or transmitter ID and associates the specific tag 102 with a specific room.
[0025] According to one embodiment of the present invention, one or more ultrasonic based transmitters 108 are located inside the room and periodically transmit a ultrasonic signal (US) which includes the room ID (i.e. Area # 1 , Area # 2 , etc.) or any other identification information (e.g. transmitter ID). Due to the non penetrating nature of ultrasonic signals (US), the tag 102 will be triggered only by the ultrasonic signal (US) of transmitters 108 that are located inside the room in which the tag 102 is located. The ultrasonic signals (US) cannot penetrate through the room walls and hence tags 102 located outside the room will not be triggered. Due to the propagation nature of ultrasonic signals (US) inside an enclosure, they will be received by the tag 102 in any position or angle inside the room. It should be noted that in FIG. 1 , doors will generally be used in the entry/exit areas of the room to prevent the ultrasonic signals (US) from triggering tags 102 on an opposite side of the entry/exit area of the room. Thus, tag # 2 in Area 2 of FIG. 1 will not receive the ultrasonic signals (US) transmitted by transmitters 108 in Area # 1 .
[0026] The tag 102 can measure the TOA (time of arrival) of several US signals received by the tag 102 and the information can be used by the location server to perform a precise location using TDOA (Time Difference Of Arrival). Measuring the ultrasonic signal TOA and the LF signal TOA with an accuracy of ±1 msec, both signals transmitted from a single transmitter also makes it possible to calculate the distance of the tag 102 from the transmitter 108 .
[0027] One key benefit of the network 100 is that the network 100 utilizes the backbone WLAN connectivity of the tag 102 in order to transmit the room and/or transmitter ID and tag ID. Thus, the network 100 does not require any additional network connectivity or new network infrastructure from the ultrasonic units.
[0028] In another embodiment of the network 100 , it is possible to increase the location accuracy of the WLAN based system 104 and not only provide the information in which room an asset is located. The transmitted ID sent by the transmitters 108 limits the location coordinates of an asset to a defined area (i.e., a defined room area), and therefore the transmitted ID can eliminate location calculation results that results in coordinates that are outside the defined room area of the transmitted ID. In another embodiment, this additional information can be used to avoid detecting an asset in a wrong floor (floor separation) as the room information is a subset of the floor information. In another embodiment of this method, the room and/or transmitter ID information can be used to filter readings of some WLAN locations receivers 110 . This way error factors (such as interference to certain location receivers) can be eliminated and the overall location coordinates calculated by the WLAN system 104 will be more accurate.
[0029] Referring now to FIG. 3 and in accordance with one embodiment, the tag 102 will include one or more ultrasonic microphones 112 . The ultrasonic microphone 112 is connected to the ultrasonic receiver module 106 that can retrieve data from the received ultrasonic signal (US). The transmitted ID from the ultrasonic signal (US) is sent to a micro processor 120 . The periodic ultrasonic signal (US) in the air will trigger the transmitter 114 which will transmit the relevant information (e.g. Room ID and/or transmitter ID) through the WLAN based location system 104 . Alternatively, the information can be stored in a memory 116 of the tag 102 and transmitted in the next session of the WLAN transmission of the tag 102 . The WLAN transmitted signal is typically transmitted periodically at predetermined intervals and will further include broadcast address, sequence number and other information relevant to the tag including tag ID and telemetry information. The transmitted signal as a minimum includes an identification number associated with the tag 102 that is retrieved from memory 116 , which may also store micro processor 120 instructions and data.
[0030] A sensor circuit 122 may be coupled to the signal processor 120 to receive signals from external sensor connector 124 or internal sensor 126 and a battery status monitoring circuit 128 may also be coupled to the signal processor 120 to indicate the strength of the power supply 130 . The battery status circuit 128 and sensor circuit 122 provide information to the signal processor 120 that may be transmitted along with the tag ID to location receivers and/or Access Points 110 in the WLAN based location system 104 .
[0031] A sniffer circuit 132 may be included to determine whether or not the WLAN channel is clear. If the WLAN channel is clear, the transmitted signal is transmitted at the predetermined time, otherwise a back-off algorithm as specified by the particular WLAN specification employed by the WLAN is applied and the signal is transmitted subsequently when the channel is clear. Alternatively, the sniffer circuit 132 may be omitted, in which case the transmitted signal is differentiated from the standard WLAN signals by using a non-standard code sequence or a non-standard preamble.
[0032] In another embodiment of the present invention, the tag 102 can utilize an already existing low frequency receiver 134 (such as the one used for the Exciters solution described above) for the purpose of receiving the ultrasonic signals (US), since the low frequency receiver 134 usually operate in the same frequency ranges (40 Khz-200 Khz). Both the ultrasonic microphone 112 and a low frequency antenna 134 A of the low frequency receiver 134 can be connected in parallel as two antennas to the low frequency receiver 134 , and the tag 102 can include both options.
[0033] In accordance with another embodiment of the present invention, the tag 102 can be triggered by a low frequency radio signal that is synchronized with the ultrasonic signal (US) at the transmitter side. In this embodiment, due to the low propagation velocity of ultrasonic waves relative to radio waves, the synchronization can be used to calculate a range between the tag 102 and the transmitter/s 108 by measuring the time delay between the radio and the ultrasonic signals (US). This information can be transmitted through the WLAN based location system 104 and be used for various location purposes such as improved location inside the room. In any case, having the ultrasound receiver side in the tag 102 and not the ultrasound transmitter enables low power consumption which will provide long battery life, as the tag 102 is a very power sensitive device.
[0034] In certain embodiments of the system, the tag 102 can have a receiving window in which the low frequency receiver 134 is periodically activated and detects existence of an ultrasound signal. The low frequency receiver 134 can be activated from an idle (power saving mode) or from a complete power down situation. This feature can be used in order to reduce the overall power consumption of the tag 102 and increase its battery life. The importance of this feature is the fact that due to the slow propagation of ultrasonic signals, reception of the message is a power consuming task for the tag 102 .
[0035] In another embodiment of the invention, a low frequency Exciter may be located at the entrance/exit of an area that has many rooms and can be used to activate/deactivate the ultrasound receiver 106 (either constantly or to activate/deactivate the periodic receive interval) in the tag 102 as it enters/exits the area. This is used in order to increase the tag's battery life, so that at time periods when it is not located in a section of the site that requires ultrasound area separation, the ultrasound receiver 106 will be deactivated completely. In another embodiment, the Exciter can be used to modify the ultrasound receive interval of the tag rather than just activating/deactivating the ultrasound receiver.
[0036] In another embodiment of the invention, the tag 102 can have its own wireless network receiver (a bi-directional tag). In a system that is capable of knowing the tag's location in other means (such as RF based location), the system will send the tag 102 through its RF receiver a command to activate/deactivate the ultrasound receiver 106 (or the periodic receive window) when it enters/exits an area that requires ultrasound area separation.
[0037] Now referring to FIG. 4 , the ultrasound transmitter 108 includes an ultrasonic transducer 108 A used to periodically transmit the ultrasonic signal. A micro processor 108 C may be used to determine when the ultrasonic signal (US) is transmitted. The ultrasonic signal (US) includes the room ID or any other identification information (e.g. transmitter ID) in its data payload. In a preferred embodiment, the ultrasound transmitter 108 will include a power supply 108 D. The power supply may be an electricity plug which will enable the transmitter 108 to be mounted on the wall and obtain power for the transmitter operation. Alternatively, the power supply 108 D can operate from a battery or be connected directly to the electricity network like a ceiling lamp. Alternatively, a few transmitters 108 can be installed inside the same room, all transmitting the same data, to ensure coverage for very large enclosures.
[0038] The room ID (or any other relevant ID) can be configured to the transmitter 108 manually, (for example, using DIP switches 108 E) or with any other interface such as serial connector 108 F and the like.
[0039] In another embodiment of the present invention, the transmitter 108 can be connected to the WLAN based location system 104 for over the network configuration purpose (such as of the room ID or output power) or to a wired network (e.g. Ethernet) for power supply using a PoE (Power over Ethernet) switch. Network configuration (wired or wireless) will enable more flexibility to the user upon installation and maintenance. When using WLAN connection, the microprocessor 108 C in the ultrasound transmitter unit 108 can be connected to the WLAN based location system 104 by integrating into the unit an optional wireless transceiver 108 G thus providing OTA (Over The Air) configuration and control.
[0040] In accordance with another embodiment of the transmitter 108 , the transmitter 108 includes integration with a low frequency transmitter 108 B such as the Exciter described above to form an ultrasonic Exciter. This will enable synchronizing the ultrasonic beacon with a low frequency radio beacon, which will enable triggering the tag with low frequency radio, for tags that prefer such triggering due to power consumption reasons.
[0041] In this embodiment, the ultrasound Exciter can include more than 1 speaker. In a typical embodiment, there shall be one speaker in front of the box, and up to 4 speakers on each side, all transmit simultaneously or sequentially. Each speaker can be activated or deactivated. The amplitude and phase of each speaker can also be controlled and set to any level between zero and the maximum output available. This feature can be used to increase the flexibility of mounting the ultrasonic Exciter in different positions in the room, optimizing its coverage over the entire room volume and reducing its leakage through openings in the room such as doors and windows
[0042] In various embodiments of the invention, the transmission frequency of the ultrasonic Exciter can vary between 20 KHz to 200 KHz. Due to higher propagation losses of the higher frequencies, higher frequencies can be used for more precise location accuracies. In other embodiments, different frequencies can be used to avoid interference for the receiver in the tag 102 (such as interference caused by other near-by US sources). Avoiding interference can be done by changing the frequency dynamically or statically.
[0043] In a certain embodiment of the invention, the ultrasound Exciters (or hybrid LF+Ultrasound Exciters) can be daisy-chained together. The chaining can be used to provide larger or optimized coverage of the ultrasound signal in a certain space, by having all Exciters transmit simultaneously (so that the space phase is correlated between them). In another embodiment, the ultrasonic Exciters can be synchronized so that each can transmit at a different time interval. This can be used to avoid air interference between their transmissions with several ultrasonic Exciters in the same room, and create higher resolution area separation in the same room.
[0044] In a typical embodiment of the invention, the ultrasound Exciter status will be monitored. This monitoring can be done by mechanisms of self test or by embedding a reduced range ultrasound receiver (such as the one used in the tags) inside the Exciter itself, to detect the transmitted signal. Monitoring indications can be done locally in the Exciter (for example, by switching an LED on) or through a network connection of the Exciter.
[0045] In a preferred embodiment of the invention, the US Exciter can be designed in a box that includes a built in AC power outlet on the back of the box, so that it can be mounted and powered by simply plugging it into the socket. This provides a combination of a simple mounting and powering solution
[0046] The present invention can also be implemented in any radio based WLAN networks. A preferred embodiment is a standard Wi-Fi network, but any other WLAN radio infrastructure, whether standard or proprietary can be used for the implementation of the present invention.
[0047] The present invention satisfies all 3 requirements for “room separation”. In the present invention, very close to 100% room separation is obtained via the introduction of ultrasonic signals into the system. The system is based upon the WLAN real time location system and hence maintains all the advantages of the WLAN location system, including the usage of existing infrastructure, the location accuracy, WLAN based services and the use of telemetry. The total cost per room is low due to the low amount of additional components required for the tag, the low cost and simplicity of the ultrasonic transmitter unit, and the utilization of the existing network infrastructure. The present invention is simple to implement and effective. It provides the above advantages in an implementation that naturally combines into the WLAN location system with minimal additional cost to the existing components, and minimal effect on the lifetime of the tag's battery.
[0048] This disclosure provides exemplary embodiments of the present invention. The scope of the present invention is not limited by these exemplary embodiments. Numerous variations, whether explicitly provided for by the specification or implied by the specification, such as variations in structure, dimension, type of material and manufacturing process may be implemented by one skilled in the art in view of this disclosure. | A wireless location system for tracking and locating a wireless tag in a structure having defined areas that provides for differentiation between the defined areas has at least one ultrasonic transmitter positioned in each of the defined areas for transmitting an ultrasonic signal having area identification and/or transmitter ID information. A plurality of wireless tags are provided wherein each wireless tag transmits a last area identifying and/or transmitter ID information received and accepted by the wireless tag in a tag message. A plurality of location receivers is installed in the structure for receiving the tag message and for reporting the received message from the tag along with optional measured parameters to a common server. The common server determines the location of each wireless tags in the structure using the defined area or transmitter ID as reported by each wireless tag. | 7 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a facility of preventing environmental pollution and processing wastewater such as excretion and urine, and sewage due to water cleaning, and more particularly, to a method for building a functional pigpen and a pigpen structure, which is built by modifying various unreasonable facilities in pig houses into an economic structure to play a multiple role, greatly reducing a cost for building and installing the pigpen, heightening productivity of pigs with a sanitary breeding management having no bacilli, harmful insects, and offensive odor, and providing a comfortable circumstance capable of heightening a working efficiency and preventing environmental pollution.
2. Description of the Related Art
In general, wastewater such as excretion and urine, and sewage due to water cleaning is generated in a pigpen during breeding. The excretion and urine pollute underground water or river, and the offensive odor has a bad influence upon a comfortable living condition. Accordingly, in view of the governmental position, a pigpen should be standardized and controlled.
The governmental control has caused a pig breeding business to be recently enlarged on a large scale. As a result, an amount of polluted materials such as wastewater including excretion and urine, and sewage due to water cleaning becomes massive to thereby cause environmental pollution and destruction which pollutes river and underground water. Also, wastewater mixed with excretion and urine, and sewage due to water cleaning is rotten to generate offensive odor, to thus have a bad influence upon the living circumstances of neighbors and towns as well as the inside and outside of the pigpen. As a result, the government should control a pig breeding business.
As an example, referring to FIGS. 1A , 1 B, 2 A– 2 B, and 3 , FIG. 1A is an exploded perspective view showing a conventional pigpen structure according to an existing pigpen standard design drawing (Korean Government Construction Department Publication No. 1993-200). FIG. 1B is a side cross-sectional view of FIG. 1A . FIGS. 2A–2B is an exploded perspective view showing a partial structure of the lateral cross-section of FIG. 1A . FIG. 3 is a plan view of a conventional pigpen.
A facility of an existing pigpen 100 according to the existing standard design drawing includes sewage channels 2 installed in the left-hand and right-hand of a working passage 1 formed in the pigpen 100 . Each of the left and right pig houses 10 includes vertically shaped pipe partitions 22 a and 23 a which are installed upright with a height of 1.2 m˜1.5 m. A vertically shaped pipe partition is installed in the front face of each pig house 10 , and thus a worker cannot feed directly into a feed bucket 13 in the pig house 10 . Accordingly, an iron-made feed input container 26 is attached on part of each partition 23 a , with which feed is not be equally supplied but inconveniently and indirectly input all at a time. The partition 23 a is used as an entrance and exit gate when the excretion generated in the left and right pig houses or the excretion and urine mixed with sawdust is collected and then water-cleaned Wastewater channels are installed in the left and right of the working passage 1 . As a result, the working passage 1 is always in a polluted state, produces offensive odor, and provides a habitat for bacilli and harmful insects. Also, the vertically shaped pipe partitions 22 a and 23 a cause an economical burden on an installation thereof. If block wall partitions are installed as an alternative, sunlight is intercepted and wastewater is absorbed on the block walls, and thus heightens humidity, to thereby provide a habitat for bacilli and harmful insects, which becomes a factor for lowering a growth rate of pigs, and further pollutes dark and dim pig houses 10 .
Also, a water supply pipe 25 is vertically connected to a plastic water supply vessel 24 installed in the rear surface of each pig house 10 , at a position higher than that of the partition 22 a. The water supply pipe 25 is connected to a water supply source of a water facility in the pigpen. As a result, the plastic water supply vessel 24 can be frozen in winter season.
Also, a wastewater storage tank 30 a is installed with a predetermined width and length under the left and right pig houses 10 from the working passage 1 . If the wastewater storage tank 30 a is full of wastewater within about 20 days (a rotting function is the most activated for 30 to 40 days after generation of the wastewater, to thus generate ammonia gas and other noxious gas, see FIG. 4 ), a wastewater tube installed in one end of the pigpen 100 is made opened, and then the wastewater is moved to a wastewater storage tank (not shown) located out of the pigpen 100 . In the case that a subsidiary facility for purifying the wastewater in a wastewater separation and filtering processing facility (not shown) is burdensome, a stirrer facility for mixing sawdust with the wastewater is provided as an alternative. However, if an amount of the wastewater is suddenly increased, the overflow wastewater can pollute the river and the underground water.
Also, the bottom surfaces of the pig houses corresponding to the underground wastewater storage tank formation position are covered with iron-made or wooden bottom plates 31 a. On each bottom plate 31 is provided excretion passing holes 32 a each having a size preventing the pig's foot from falling into the hole. Accordingly, excretion and urine and sewage due to water cleaning fall into the wastewater tank under the pig house 10 . That is, when pigs are eating, sleeping and playing in the pig house with the excretion and urine and sewage due to water rubbed and tread by their bodies and feet, the excretion and urine and sewage due to water fall into and are collected in the underground wastewater storage tank 32 through the excretion passing holes 32 a.
As described above, the existing pigpen 100 constructed by the conventional standard design drawing has been built under the wrong recognition that pigs are dirty animals which do not discriminate an evacuation place from a lodging place. As a result, excretion and urine are in a muddle at a place of the pig house 10 , which pollutes the bottom plates 31 a, the partition and block walls, the bottom surface of the pig house 10 and the feed bucket 13 , in whole, and smells offensive odor due to the moisture.
Also, the bottom plates 31 a are always wet due to the successively evacuated excretion and urine, which become habitats of various bacilli, or harmful insects during a zymolysis process of the wastewater contained in the underground storage tank. These circumstances raise various diseases such as fatal pneumonia, bronchial disease, or skin disease to pigs, and thus have a bad influence on a pigs breeding businessman due to a high death rate and a low growth rate of pigs and a deteriorated international competitiveness of a pig breeding business.
Pigs are severely stressed due to the unreasonable structure in the pig houses 10 . Accordingly, it is necessary to perform water cleaning with high-pressure sprayed water. As a result, an amount of wastewater is increased due to the mixture of excretion and urine and sewage due to water cleaning, which requires for a bigger underground wastewater storage tank 30 a in each pig house 10 . Accordingly, a self-control purifying facility and a public pigpen wastewater processing facility face to social problems based on natural surroundings.
An amount of wastewater generated per day from a pig is 8.6 kg which is shown in Korean Government Environment Department Publication No. 1999-109. Since a total number of pigs bred in 2001 is about 88 millions, a yearly amount of wastewater generated is about 27 million tons. A BOD concentration of the wastewater is 20,000˜25,000 ppm. By the way, since a local facility built in each province is a public pigpen wastewater processing facility which processes the wastewater based on the BOD concentration of 5,000 ppm, such facilities cannot run at present.
As an alternative of solving the above problems, the underground wastewater storage tank 30 a is made closed. The cement bottom is covered with sawdust of 40 cm˜50 cm, on which pigs are evacuated and living. This raises an ill effect. Sawdust includes components of tannin acid and lignin acid which are harmful for pigs. Thus, if pigs eat the sawdust, they suffer from indigestion, and if they breathe sawdust, they suffer from pneumonia. Also, since noxious gases are generated due to a rotting function of excretion mixed with sawdust, a growth rate is reduced and a death rate is increased. Collection of excretion mixed with sawdust and water cleaning are performed in the working passage 1 . Since the working passage 1 is always in a polluted state, offensive odor and bacilli and harmful insects are generated in both the pig houses 10 and the working passage 1 .
As an alternative in case that an investment cost is burdensome, the bottom surface of each pig house 10 is plastered with concrete without having a wastewater storage tank 30 a under each pig house 10 , and then sawdust of 50 cm or so (or 1.0 m) high is put into the pig house 10 , on which pigs are living and thus evacuated excretion and urine are naturally mixed with sawdust. Thus, the underground wastewater storage tank 30 a need not be installed, but an amount of sawdust mixed with the excretion and urine becomes massive, which requires for a subsidiary processing facility. Also, since all the things are accomplished in the working passage 1 , a manpower required becomes double. Thus, the pigs breeding business is one of 3D (Dirty; Difficulty and Danger) industries, which causes a difficulty in obtaining a manpower. Also, since the height of the partition is heightened by the height of the sawdust laid, the partitions screen pigs from being visible to a worker which prevents sanitary breeding management.
Also, since the structure of the working passage 1 has a width of 1.05 m and the front-surface vertically shaped pipe partition is installed upright with a height of 1.2˜1.5 m, working space is narrow. Thus, it is impossible to perform all the works with a shovel while moving the upper body of a worker. As an alternative, a business person installs a passage with a width of 1.5 m˜2.0 m and also sewage channels 2 in the left and right sides of the passage to convenience all works. However, since a worker should bend his or her upper body when he or she supplies food into the feed buckets 13 in the left and right pig houses, a physical fatigue is added and a feeding time is increased.
Also, since the vertically shaped partitions 23 a are installed in the front surfaces of the pig houses, according to the existing standard design drawing, it is difficult to supply food from the working passage 1 . Thus, an iron-made feed input bucket 26 is attached on part of the vertically shaped partition in each pig house 10 . Meanwhile, length of a feed bucket 13 attached on the bottom of the pig house 10 corresponds that of the feed input bucket 26 . Thus, if feed is put into the feed input bucket 26 , pigs fight crying with each other when they eat since the length of the feed bucket 13 is short in comparison with the number of pigs, which makes the pigs stressed. During fighting, feed are scattered out of the pig house, which causes a loss of feed.
Meanwhile, in the structure of the pigpen 100 according to the existing standard design drawing, the partitions constituting the pig house 10 are made of metal pipes in order to secure economic installation, breeding management convenience, working efficiency, ventilation and lighting for sanitary management. However, since the partitions are installed in vertical shape, it is difficult to supply feed for a feed bucket 13 installed in the pig house 10 . As an alternative, a feed input bucket 26 is attached on part of the vertically shaped partition in each pig house 10 . Accordingly, the food supplied in the feed input bucket 26 should move to the feed bucket 13 . In the structure of the pigpen 100 according to the existing standard design drawing, when the pipe partition in each pig house 10 is vertically installed, an amount of pipes consumed for the metal pipe partition is calculated as follows.
The size of each of the left and right pig houses 10 along the working passage 1 is 3 m×4.125 m. A pipe is cut into eight pieces of 1.35 m (an average length of 1.2 m˜1.5 m) in units of meter, and then the eight pieces of pipes are vertically welded. In this way, if four partitions are installed upright around the four walls of the pig house, an amount of consumed vertically shaped partitioning pipes 22 a and 23 a becomes 182 m. Also, since the whole length of the pig houses 100 according to the existing standard design drawing is 92 m, a total number of the pig houses 10 which are installed in the left and right of the working passage 1 is 58. Accordingly, a total length of the total pipes consumed for the vertically shaped partitioning pipes in the pig houses 10 becomes 10,556 m (=58 rooms×182 m).
Here, the water supply pipe 25 connected to the plastic water supply vessel 24 in each pig house 10 consumes a water supply pipe of 8 m. Since the total number of the whole pig houses is 58, an amount of the water supply pipes consumed is 464 m (=58 rooms×8 m). Accordingly, the total length of the pipes consumed is 13,054 m in addition to the metal partitioning pipes.
As described above, in order to install the vertically shaped partitions, metal pipes are cut and then welded which causes cost of a welding process for the vertically shaped partitions. Also, each of the 58 plastic water supply vessels are installed in each pig house 10 , and each of the 58 iron-made feed input buckets 26 are installed in each pig house 10 . As an alternative because the above structure is burdensome economically, a gate is installed on the vertically shaped partition in the front surface of each pig house 10 , and an iron-made feed input bucket 26 is installed on part of the gate. It is general to install cement block wall partitions in the remaining three walls.
Therefore, the existing, pigpen installation structure has the following problems.
Due to polluted circumstances in a pigpen because of wastewater, productivity of pig meat is not increased up to a level of developed countries which perform a sanitary breeding management under the comfortable circumstances in and out of the pigpen.
Since materials consumed various structures and elements in the pigpen are not utilized in multiple purposes, only subsidiary facilities are increased which adds an economical burden on a breeding business person; to thereby increase a production cost.
In view of the structural improvement in the pigpen, a working efficiency of breeding pigs is not accomplished, and thus the breeding business is not escaped from a 3D business group to thereby cause a difficulty in securing a manpower.
SUMMARY OF THE INVENTION
To solve the above problems, it is an object of the present invention to provide a method for building an environment-affinitive pigpen and a pigpen structure in which a structure of a pig house in the pigpen is divided into an evacuation room, a lodging room, and a feed bucket, so that pigs evacuate excretion and urine in the evacuation room, to thereby prevent pollution of the lodging room and to thus constitute comfortable and sanitary breeding circumstances, and so that excretion evacuated in the evacuation room is collected in a lump and urine naturally flows down to thereby automatically separately collect the excretion and urine and convenience collection of excretion and urine.
It is another object of the present invention to provide a method for building an environment-affinitive pigpen and a pigpen structure in which a power cable is installed on a partitioning pipe in the pig house, horizontally with respect to the pipe, to thereby build the height of the partitioning pipe with half the height in comparison with the existing partitioning pipe, and to thus save a facility cost.
It is still another object of the present invention to provide a method for building an environment-affinitive pigpen and a pigpen structure in which the height of the partition in the pig house is lowered to thereby facilitate an observing of the pig breeding states, and enhance a working efficiency.
It is yet another object of the present invention to provide a method of building an environment-affinitive pigpen in which a pig house is divided into an evacuation room and a lodging room so that urine excreted in the evacuation room is naturally moved into an external urine storage tank, and in which if each gate of the evacuation rooms is opened, pigs cannot go out of the lodging rooms, and the evacuation rooms are converted into a working passage to thereby conveniently and easily do an excretion collection work and separately collect excretion and urine.
It is still yet another object of the present invention to provide a method of building an environment-affinitive pigpen having a heating facility, in which pipes constituting each pig house are utilized as water supply pipes and they are used as heating pipes.
It is a further object of the present invention to provide a method of building an environment-affinitive pigpen, in which excretion and urine can be separately collected without water cleaning, so that a BOD concentration of the urine is within 5,000 ppm, to thereby water-process the urine through a public wastewater processing facility and make the excretion decomposed at a low cost.
It is still a further yet another object of the present invention to provide a method of building an environment-affinitive pigpen, in which an underground wastewater storage tank is not installed under each pig house, and thus urine is made to flow into an underground urine storage tank in the field of making excretion decomposed far away from a pigpen, so that ammonia gas or noxious gas caused by rotting of the wastewater does not go up to a pig house to thereby prevent generation of offensive odor fundamentally, and provide a comfortable and sanitary pigpen.
It is still yet a further object of the present invention to provide a method of building an environment-affinitive pigpen, in which no works such as excretion collection works and going in and out of a pig house which can cause a series of pollutions are performed in a working passage, and thus the working passage can be prevented from being dirty due to the wastewater to thus maintain the working passage to be cleanly and to thus improve insanitary and uncomfortable working conditions to resultantly help overcoming a difficulty in finding a manpower.
To accomplish the above object of the present invention, according to an aspect of the present invention, there is provided a method of building an environment-affinitive pigpen breeding pigs in pig houses successively provided in the lengthy direction of the pigpen, in which the pigpen is partitioned into pig houses, each pig house being divided into a feed bucket, a lodging room, and an evacuation room, where an entrance and exist gate which is opened and closed on a frame for partitioning the pig houses installed between the pig houses is provided, and if the gate is opened, an evacuation room in a successively installed pig house is converted into a single passage to collect excretion, in which case urine excreted in the evacuation room flows down into an external urine storage tank out of the pigpen through a urine tube.
The evacuation room is slantly formed on the bottom surface in, order to collect the urine, so that the urine naturally flows down into the urine tube connected to the external urine storage tank out of the pigpen, to thereby separately collect the urine from the excretion without having an additional labor force, and to thereby collect the urine within a BOD concentration of 5,000 ppm, and thus to enable the wastewater of the urine to be processed at a low cost through a nationwide public wastewater processing facility, and to resultantly re-run a resting wastewater processing facility.
The pipes of partitions constituting each pig house are installed horizontally, in which a power cable is installed so that pigs do not step over the horizontally installed pipes, to thus enable the height of the partitions to be about half the existing height, and to thus save the facility cost and widen a field of vision in the pigpen to easily observe and sanitarily control the breeding state of the pigs.
Also, each pig house is divided into the evacuation room and the lodging room, so that the lodging room is not polluted by excretion, to thereby prevent the pigs from suffering from diseases basically and prevent offensive odor to provide a sanitary and comfortable working condition.
Also, since the pipes for partitions installed between the pig houses and the pipes positioned toward the working passage are all horizontally installed, in which the lower-end pipe can be utilized as a water supplying pipe, and the left and right partitioning pipes can be utilized as heated water circulation pipes, that is, the pipes have the functions of the partitioning and circulating the water supply and heated water.
The evacuation room provides a multiple function playing a role of a passage function which enables pigs to go in and out from the pig house and a working passage function for collecting excretion, in addition to the evacuation room.
Also, if an evacuation room gate provided between the evacuation room and the lodging room is opened toward the lodging room, pigs cannot go out from the pig house, to thereby perform an excretion collection work freely from interruption of the pigs during collection of excretion. Meanwhile, if an evacuation room gate provided between the evacuation room and the lodging room is opened toward the evacuation room, the evacuation room and the lodging room communicate with each other and the neighboring evacuation rooms are blocked from each other to thereby constitute an independent pig house.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and advantages of the present invention will become more apparent by describing the preferred embodiment thereof in more detail with reference to the accompanying drawings in which:
FIG. 1A is an exploded perspective view showing a conventional pigpen structure;
FIG. 1B is a side cross-sectional view of FIG. 1A ;
FIGS. 2A–2B are exploded perspective view showing a partial structure of the lateral cross-section of FIG. 1A ;
FIG. 3 is a plan view of a conventional pigpen;
FIG. 4 is a graphical view showing a decomposition proceeding state after having contained wastewater mixed with excretion and urine and sewage in a wastewater tank;
FIGS. 5A–5B are exploded perspective view partially showing the essential portions of a pigpen according to the present invention;
FIG. 6 is an exploded enlarged perspective view partially showing the structure in pig houses according to the present invention;
FIGS. 7A–7B are cross-sectional views of the pigpen structure according to the present invention;
FIG. 8 is a plan view of a pigpen according to the present invention, in which evacuation rooms and a lodging rooms communicate with each other; and
FIG. 9 is a plan view of a pigpen according to the present invention which is similar to that of FIG. 8 , where an evacuation room is modified into a single path.
DETAILED DESCRIPTION OF THE INVENTION
Hereinbelow, a method of building an environment-affinitive pigpen, and a pigpen structure according to the present invention will be described in detail with reference to the accompanying drawings.
FIGS. 5A–5B are perspective view showing a pigpen structure according to the present invention. The same elements as those of the existing elements are assigned the same reference numerals as those of the existing elements.
In the drawings, a reference numeral 100 denotes the whole of a pigpen. A reference numeral 1 denotes a working passage through which a worker or workers can pass in the inside of the pigpen 100 . A reference numeral 10 denotes a pig house in which pigs are bred. A reference numeral 20 denotes partitioning pipes including partitioning pipes 22 and 23 which partition the pig house. A reference numeral 30 b denotes a urine storage tank in which urine is input.
The pig houses 10 can be successively and symmetrically installed in the left and right sides of the center of the working passage 1 , or either of the left and right sides thereof.
As shown in FIG. 6 , the pig house 10 is partitioned by partitioning pipes 10 a so that it is divided into an evacuation room 11 in which pigs excrete and a lodging room 12 in which pigs live. This is a result from the long observation and experiment for habits with respect to excretion of pigs. That is, pigs have certain intelligences with which pigs can discriminate an excreted place from a sleeping place. Thus, the evacuation room and the lodging room are separately provided by using the above habits of pigs.
FIG. 6 is an exploded enlarged perspective view partially showing the structure in pig houses according to the present invention. FIGS. 7A–7B are cross-sectional view of the pigpen structure of FIG. 6 . Referring to FIGS. 6 and 7 A– 7 B, a feed bucket 13 is installed in the lodging room 12 of the front surface of the pig house in the lengthy direction of the pigpen. The evacuation room 11 is preferably installed at a place lower than the bottom surface of the lodging room 12 . According to a preferred embodiment of the present invention, the bottom surface of the evacuation room 11 is formed at a position lower y about 10˜20 cm than that of the lodging room 12 .
The reason is to prevent excretion of the evacuation room 11 from adhering to the pigs and moving into the lodging room 12 when the pigs reciprocate between the evacuation room 11 and the lodging room 12 . Further, the bottom surface of each evacuation room 11 is slantly formed toward the central portion thereof. On the center of the evacuation room 11 is a urine tube 31 connected to a urine storage tank 30 b buried at a place from away from the pigpen 100 , for example, under an excretion decomposition area. A manhole is formed at the entrance of the urine tube 31 so that excretion does, not go in and urine naturally flows in.
The urine tube makes the urine excreted on the bottom surface of the evacuation room 11 go into the urine storage tank 30 b. At a place in the middle of the urine tube is further installed an excretion sludge vessel 32 in order to collect a small amount of excretion separately before having arrived at the urine storage tank 30 b when the small amount of excretion has been input together with the urine which has been input into the urine tube 31 . The excretion deposited in the excretion sludge vessel 32 is removed by a special spoon. Thus, only excretion is left in the evacuation room 11 .
An exit is provided in the evacuation room 11 and the lodging room 12 , respectively, so that pigs can go in and out. The exit is opened and closed by the evacuation room gate 21 . That is, as shown in the drawing, the evacuation room gate 21 is combined with a frame provided between the pig houses 10 so as to be opened and closed through a hinge.
If the evacuation room gate 21 is opened toward the lodging room 12 , pigs go in the lodging room 12 , in which case the evacuation room 11 communicates with the neighboring evacuation rooms. As shown in FIG. 9 , if the evacuation room gates 21 installed in the respective evacuation room 11 are successively opened toward the lodging rooms 12 , all the evacuation rooms 11 are deformed into a single long working passage. The excretion is pushed out by a motor car at any one direction in the evacuation room 11 , or the excretion is dug out by a plastic shovel to thereby remove the excretion to an excretion decomposition area easily and conveniently. Also, the evacuation room gates 21 are functional portions having an opening and closing function of an exit for making pigs go into the pig houses 10 , respectively.
If the evacuation room gate 21 having a partitioning function is restored into an original position after having collected excretion as shown in FIG. 8 , the evacuation room 11 and the lodging room 12 communicate with each other so that pigs can go in and out between the evacuation room 11 and the lodging room 12 . Also, the evacuation room 11 is independently separated from an excretion collection passage or the pig house 10 is independently separated from each pig house.
In the present invention, the partitioning pipes 20 which partition the pig houses 10 are all installed horizontally. In particular, it is preferable that the front-side partitioning pipes 23 in the pig house 10 are slantly installed by about 60˜70°.
The reason why the front-side partitioning pipes 23 in the pig house 10 have been slantly installed is to widen a space so that a worker can freely move the upper body although the width of the working passage 1 is formed more narrowly by about half than the existing working passage width of 1.5˜2.0 m. Accordingly, a worker can freely work in the working passage. Also, since the width of the working passage can be reduced half the width of the existing working passage 1 , an architectural area can be efficiently used.
However, when the partitioning pipes 20 are horizontally installed, pigs can go up the pipes. To prevent this, a power cable 40 is installed on the upper end of the pipes so that pigs cannot go up the pipes.
An electric switch is turned on so that current flows through the power cable 40 when a worker approaches the working passage 1 . If the worker approaches the working passage 1 , pigs may misunderstand that the worker will supply them with feed. In this case, as soon as pigs go up the horizontally installed pipes 20 , they contact the power cable 40 and undergo a minor electric shock, which can prevent pigs from going up the pipes. If the worker passes away from the working passage 1 , the electric switch is turned off to cut off current flowing through the power cable 40 .
Since the power cable 40 is installed on the upper portion of the partitioning pipes 20 in the present invention, the height of the existing partitioning pipes 20 can be lowered by about half. As a result, a cost of facilities in the pigpen can be saved by about one third or more. Also, since a field of vision in the pigpen 100 is widened, a breeding state of pigs can be easily checked and a sanitary management breeding is easily accomplished.
The front-side partitioning pipes 20 in the pig house 10 are horizontally installed, and the lowest-end pipe is used as a water supply pipe 23 b. That is, the lowest-end pipe of the front-side partitioning pipes 20 in the pig house 10 is connected to a water supply pipe to automatically feed water therein. Thus, water can be automatically supplied to a feed bucket 13 .
Further, an automatic water supply 28 and a water tap 27 are additionally provided in the water supply pipes 23 b. At normal times, drinking water is supplied by the automatic water supply 28 , and at emergency times drinking water is supplied to the feed bucket 13 in each pig house 10 . In this case, the feed bucket 13 plays a role of a water vessel as well.
As described above, since the emergency water tap 27 is added in the water supply pipe 23 b passing through the front-side lodging room 12 in each pig house 10 , a water supply vessel 24 of FIG. 1 and a water supply pipe 25 of FIG. 1 need not be additionally installed as in the existing pigpen. Further, the front-side partitioning pipes 23 in the pig house 10 circulate hot water for heating in which the front-side partitioning pipes 20 in the pig house 10 can be used as a heating water circulation pipe. As shown in FIG. 6 , as an alternative of the heating water circulation pipe, a heating pipe 12 a can be installed on the bottom surface of the lodging room 12 .
Moreover, the working passage 1 provided between the pig houses 10 is preferably formed at a position lower than the height of the pig house 10 , preferably by 40˜50 cm. The reason is to make a worker in the working passage 1 work without bending his or her waist and at a standing position.
Here, as described above, the partitioning pipes 20 are horizontally installed to thereby conveniently feed without having the spilt feed which may be caused because the work may be hit and interrupted by the partitioning pipes 23 during feeding. Accordingly, the working passage 1 is clean and sanitary. Thus, the existing iron-made feed input vessel 26 is not needed any more.
As described above, the present invention separately provides the evacuation room 11 in each pig house in order to separately collect excretion and urine. Accordingly, the present invention need not do water cleaning and generate cleaning sewage at all. As a result, a wastewater storage tank and a purifying facility for separately filtering and processing wastewater need not be installed under the pig houses. Also, since a BOD concentration of the urine collected separately from the excretion is 5,000 ppm or less, a pigpen wastewater pressing facility which is a resting facility can be used to process water.
As described above, the effects according to the present invention are summarized as follows.
Excretion and urine are separately collected fundamentally in advance. Accordingly, excretion having a small amount of moisture is decomposed and then commercialized, and urine can be used as liquid fertility at once. However, if a breeding business person has no cultivating land, he or she sends the wastewater to a public pigpen wastewater processing facility to be purified. Here, since a BOD concentration of urine is 5,000 ppm or less which can be processed in a nationwide public wastewater processing facility, the public pigpen wastewater processing facility which is a resting facility can be re-run to perform purification.
An existing pigpen processes wastewater post factor, but the pigpen according to the present invention need not do a water cleaning work, and separately collects excretion and urine fundamentally in advance to prevent an environmental pollution.
Pigs are bred by dividing a pig house into an evacuation room and a lodging room. The excretion and urine are separately collected differently from the wastewater mixed with excretion, urine and sewage due to water cleaning in an underground wastewater storage tank in an existing pig house, to thereby prevent harmful insects or bacilli from growing, and thus accomplish a sanitary breeding circumstance.
The present invention installs a urine storage tank under an excretion decompost area far away from a pigpen, differently from a wastewater storage tank installed under each pig house installed in an existing pigpen. Thus, offensive odor or noxious gas generated from the rotten urine stored in the urine storage tank does not go up to the pigpen. Accordingly, pigs can be prevented from being infected with various diseases. As a result, a growth rate of pigs can be heightened and a more comfortable or sanitary working circumstance can be accomplished.
The present invention makes excretion and urine separately collected in each evacuation room, and no works in a working passage, to thereby maintain the working passage cleanly and sanitarily all at times. Accordingly, foreign buyers or visitors can see overall breeding circumstances such as a sanitary breeding circumstance, a comfortable working circumstance, and a practical workability, to thereby promote a reliability with respect to all the breeding processes. As a result, the present invention can contribute an increase of export and solve a difficulty in finding a manpower by improving a worse working circumstance to be a comfortable and sanitary working circumstance.
The height of the partitioning pipes in each pig house is lowered. As a result, a cost of facilities in the pigpen can be saved by about one third or more. Also, since a field of vision in the pigpen 100 is widened, a breeding state of pigs staying in each pig house.
Partitioning pipes are horizontally installed. The pipes are used as a water supply pipe or a heating hot water circulation pipe which is used as a heating device for each pig house.
The upper portions of the pipes are slantly installed toward the pig house. Although the width of the working passage in the pigpen is narrowed in comparison with the conventional art, no impediment occur. Thus, a pigpen area can be effectively used.
An existing pigpen collects wastewater generated by high-pressure water cleaning in order to clean excretion and urines and processes them in a bundle. The present invention separately collects excretion and urine fundamentally and does not perform any water cleaning, to thereby an environment-affinity pigpen structure without generating wastewater basically.
As described above, the present invention has been described with respect to particularly preferred embodiments. However, the present invention is not limited to the above embodiments, and it is possible for one who has an ordinary skill in the art to make various modifications and variations, without departing off the spirit of the present invention. | A pig pen structure has a walking passage and a plurality of pig houses for housing an animal installed along the walking passage. Each pig house has an evacuation room, a lodging room having front, back, and two side walls, and an evacuation room gate installed between the evacuation room and the lodging room. The evacuation room is accessible to the animal for excretion when the evacuation room gate is opened. The evacuation room gate when closed becomes a part of the back wall. A urine tube is installed on the bottom of the evacuation room, so that the excreted urine in the evacuation room flows down to the urine tube to remove the excreted urine outside the pig house. The plurality of the pig houses is arranged so that the front walls of the pig houses adjoin the walking passage. A continuous passage way is formed by the evacuation rooms along the back wall of the lodging room when the evacuation room gates of the pig houses are in closed position. | 0 |
Attention: More than one reissue application has been filed for the reissue of U.S. Pat. No. 5 , 840 , 556 . The reissue applications are application Ser. Nos. 09 / 716 , 319 ( the present application ) and 09 / 971 , 575 .
This application claims benefit of priority under 35 U.S.C. 119(B) of Provisional application 60/016,311, filed May 8, 1996.
BACKGROUND OF THE INVENTION
Pasteurella haemolytica, P. multocida, and Haemophilus somnus are members of the Family Pasteurellaceae. Each is involved in respiratory disease syndromes in domestic cattle. These organisms have proven difficult to genetically manipulate, and therefore the construction of live, attenuated vaccines has been hampered.
Live attenuated bacterial strains generally provide superior protection as compared to killed bacterial vaccines (bacterins). In general, live vaccines elicit a stronger cell mediated response in the host than do bacterins. The superior immunity provided by attenuated live organisms may be explained by their ability to induce expression of stress-proteins and, possibly, of certain toxins within the host. The immune response generated by live organisms can be directed against these abundant proteins and thereby provide better protection.
There is a need in the art for live, attenuated vaccines against respiratory disease syndrome in domestic cattle caused by the Pasteurellaceae. There is also a need for techniques and tools to facilitate the construction of such vaccines.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a replication-conditional plasmid.
It is another object of the invention to provide a cell-free preparation of a plasmid which is purified from genomic DNA and which is replication-conditional.
It is still another object of the invention to provide Pasteurellaceae host cells which comprise a plasmid which is replication-conditional.
It is an object of the invention to provide methods for introducing DNA into H. somnus.
It is an object of the invention to provide methods for mutagenizing H. somnus.
It is an object of the invention to provide H. somnus transformant strains.
It is an object of the invention to provide H. somnus mutant strains.
It is another object of the invention to provide genetically engineered H. somnus.
It is an object of the invention to provide a method of introducing a DNA segment into a Pasteurellaceae genome.
It is another object of the invention to provide genetically modified Pasteurellaceae.
These and other objects of the invention are provided by one or more embodiments described below. In one embodiment a plasmid which is conditional for replication in H. somnus, P. multocida, and P. haemolytica is provided.
In another embodiment of the invention a cell-free preparation of plasmid DNA is provided. The plasmid DNA is purified free of genomic DNA. The plasmid is temperature-conditional for replication in H. somnus, P. multocida, and P. haemolytica.
In another embodiment of the invention a host cell of the family Pasteurellaceae is provided. The host cell comprises a plasmid which is replication-conditional in H. somnus, P. multocida, and P. haemolytica.
In one embodiment of the invention, a method of introducing DNA to H. somnus is provided. The method comprises the steps of: providing a DNA molecule; methylating the DNA molecule with a methyl transferase enzyme having a recognition site of 5′-GCGC-3′, to form methylated DNA; and transforming H. somnus cells with the methylated DNA.
In another embodiment of the invention a method for producing a mutation in a particular region of DNA of an H. somnus genome is provided. The method comprises the steps of: isolating a region of the genome from H. somnus; introducing a mutation into the region to form a mutated DNA region; methylating the mutated DNA region with a methylating enzyme which inhibits endonuclease cleavage at a recognition sequence 5′-GCGC-3′ to form methylated DNA; introducing the methylated DNA into an H. somnus cell to form transformants; and screening the transformants for those which have the mutation in the region on chromosomal DNA of the H. somnus cell.
In yet another embodiment of the invention a preparation is provided of an isolated HsoI restriction endonuclease.
In still other embodiments H. somnus mutants and transformants made by the process of the invention are provided.
In another embodiment of the invention a method is provided of introducing a DNA segment to a Pasteurellaceae genome comprising: administering to a Pasteurellaceae cell a recombinant construct comprising the DNA segment and a plasmid which is temperature-conditional for replication in the Pasteurellaceae cell to form transformants; subjecting the transformants to a non-permissive temperature; screening the transformants for the presence of the DNA segment; and screening the transformants for the absence of the plasmid.
In yet another embodiment a genetically modified Pasteurellaceae is provided which is made by the method of administering to a Pasteurellaceae cell a recombinant construct comprising the DNA segment and a plasmid which is temperature-conditional for replication in the Pasteurellaceae cell to form transformants; subjecting the transformants to a non-permissive temperature; screening the transformants for the presence of the DNA segment; and screening the transformants for the absence of the plasmid.
These and other embodiments of the invention provide the art with the means to construct desirable mutants and transformants of the economically important and previously intractable Pasteurellaceae family of pathogens.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the generation of defined mutations in the Pasteurellaceae, it is desirable to introduce a segment of the genome carrying a defined mutation which has been made either in vitro or in another bacterium. Typically, the segment of the genome is introduced on a plasmid. In order to “transfer” the defined mutation from the incoming DNA to the genome, homologous recombination is required. A single recombination event will result in integration of the entire plasmid, which results in one wild-type and one mutant copy of the gene. A second recombination event is desirable, to delete the wild-type copy of the gene and the vector sequences. Since the occurrence of the desired double recombination is a rare event, occurring in only a fraction of the cells which receive the introduced DNA, increasing the number of cells which contain the introduced DNA will increase the recovery of cells which are double recombinants. The use of a plasmid which can replicate in the Pasteurellaceae increases the number of cells which have the introduced DNA. However, the presence of a plasmid in cells which may ultimately be used for vaccines is undesirable, as such plasmids often contain ecologically and medically undesirable drug- and toxin-resistance determinants.
The inventors have solved this problem by creating a plasmid which does not replicate under defined conditions, i.e., which is conditional for replication. Thus genomic DNA carrying a defined mutation introduced to cells via the plasmid can be present in many copies in many directly transformed and progeny cells, by growing the cells at the permissive temperature. This feature increases the absolute number of desired double recombinants obtained by increasing the starting population of cells carrying the DNA-segment. In addition, by switching to the non-permissive conditions (e.g., high temperature), one can eliminate plasmids which are episomal. It is a discovery of the present invention that placing such plasmid-bearing bacteria at a higher temperature which does not permit efficient plasmid replication, results in quick loss of the plasmid.
The conditionality of the replication of the plasmids of the present invention can be based on any selectable phenotype. For example, the plasmids might be unable to replicate in the presence of a particular agent, such as a drug or toxin. The plasmids might not be able to replicate in the presence or absence of certain metabolites or salts. Temperature-conditionality has been demonstrated for a mutant of pD70, but other conditionalities can be used, as well as other plasmids which replicate in the Pasteurellaceae. Particularly preferred are those plasmids of the same incompatibility group as pD70.
The plasmids of the present invention can be purified according to any art recognized method from genomic DNA Typical separations of plasmid from genomic DNA in a cell-free preparation are electrophoretic, chromatographic, density gradient sedimentation, alkaline lysis, etc. The plasmids can be introduced into bacterial host cells of the Pasteurellaceae by any means known in the art, including transformation, conjugation, liposome mediated gene transfer, particle bombardment, etc. Any Pasteurellaceae host can be used.
Plasmid mutations may be induced by any means known in the art. These include in vitro or in vivo chemical mutagenesis, passage through a mutator strain, etc. Even spontaneous mutations can be used if one is willing to screen more extensively. Particularly preferred are deletions and insertions which are non-reverting. Such mutations are easily generated in vitro using restriction enzymes, for example. Conditional mutations are most likely missense mutations, but nonsense mutations can also be used in the presence of a temperature-sensitive suppressor tRNA.
The temperature-conditional plasmids of the present invention can be administered to a Pasteurellaceae cell according to standard methods known in the art, including, but not limited to electroporation, transformation, transfection, transduction. One can screen by genetic or physical methods to detect those cells which have received the plasmid DNA Subsequently, one can screen among the plasmid recipients for those which have lost the plasmid and retained the DNA of interest carried on the plasmid. The screening methods can be genetic or physical, such as screening for a phenotype or screening for the presence of a particular DNA sequence in the cell by hybridization.
It is an additional discovery of the present invention that H. somnus contains a restriction-modification system, called herein the HsoI system. The HsoI restriction endonuclease has been isolated and its cleavage sequence determined to be 5′-GCGC-3′. It has also been discovered by the present inventors, that a barrier to transformation of H. somnus can be overcome by treating DNA with a methylating enzyme, such as the HsoI methyl transferase (M. HsoI). Such enzymes modify DNA substrates such that endonucleases which recognize 5′-GCGC-3′ sequences are inhibited in their ability to digest such modified substrates. The methyl transferases produce a site which is 5′-GmCGC-3′, i.e., the 5′ cytosine is methylated. Examples of such methyl transferases are HsoI methyl transferase, HinPI methyl transferase, and HhaI methyl transferase, which is commercially available from New England Biolabs, Beverly, Mass., 01915. Cells containing such methyl transferase enzymes can also be used. Preferably, these are recombinant cells with the methyl transferase enzymes introduced, so that they lack the cognate restriction enzyme. Alternatively, they are mutant or natural variants which lack the cognate restriction enzyme. In some instances, it may be possible to passage DNA through cells which have both the restriction and methyl transferase enzymes, if the former is less active (slower) or less prevalent than the latter.
Methylation of DNA substrates for transformation (electroporation, or other means of introduction of DNA into cells) can be accomplished in vitro or in vivo. For in vitro methylation, DNA is incubated with a preparation of methyl transferase in the presence of a methyl donor, such as S-adenosylmethionine (SAM). In vivo methylation can be accomplished by passaging the DNA substrate through a bacterium which contains an appropriate methyl transferase, such as HsoI, HinPI, or HhaI methyl transferase. A mutant or natural variant of H. somnus which lacks the HsoI endonuclease could also be used to prepare DNA for subsequent introduction into H. somnus. Such a mutant can be made inter alia according to the method for site-directed mutagenesis disclosed herein.
Site-directed mutagenesis of H. somnus can be accomplished according to the present invention by first isolating a wild-type DNA region from H. somnus. A mutation is created in the isolated, wild-type DNA region according to any method known in the art. For example, the isolated DNA can be chemically mutagenized, either in a bacterium or in vitro. Alternatively, restriction endonucleases can be used to create precise deletions or insertions in vitro. Other methods as are known in the art can be used as is desirable for a particular application.
After H. somnus DNA has been isolated and mutagenized, it is methylated as described above. Then it can be introduced into H. somnus according to any technique known in the art, including but not limited to transfection, transformation, electroporation, and conjugation. Alternatively, rather than methylating the mutagenized DNA and introducing it into a H. somnus which expresses HsoI restriction endonuclease, one can omit the methylation of the mutagenized DNA and introduce the mutagenized DNA into an H. somnus, H. haemolyticus, or H. influenza cell which does not efficiently express the HsoI restriction endonuclease or an isoschizomer of it. Such cells can be isolated from nature by extensive screening, isolated following chemical mutagenesis of a cell which does express the HsoI restriction endonuclease, or made by the site-directed mutagenesis method disclosed herein. According to one aspect of the invention, the mutagenized and methylated H. somnus DNA region is introduced into a P. multocida cell on a plasmid which includes a P. haemolytica approximately 4.2 kb streptomycin resistance determining plasmid (pD70). This plasmid has also been deposited at the American Type Culture Collection, 12301 Parklawn Drive, Rockville, Md., 20852, USA, on Dec. 2, 1993, under the terms of the Budapest Treaty as Accession No. ATCC 69499. Derivatives of this plasmid or other pD70-incompatible plasmids can be used similarly. The origin of replication of pD70 can be isolated on a 1.2 kb Sau3AI fragment immediately downstream of the streptomycin resistance determinant. Gene conversion can be monitored inter alia by Southern hybridization with probes to the gene of interest, by screening for genetic markers on the introduced DNA construct (such as ampicillin® or streptomycin®), and by screening for the presence/absence of plasmid in the transformed cells' progeny.
Also provided by the present invention are mutant and transformant strains made by the disclosed methods of transformation and/or site-directed mutagenesis. Such mutants can provide the veterinary arts with attenuated, live strains of Pasteurellaceae, which are suitable for vaccines to induce protective immunity against Pasteurellaceae infection. For vaccine production, it is desirable that the mutation which attenuates the bacterium be an essentially non-reverting mutation. Typically these are deletion or insertion mutations, the latter not being caused by a transposable element. Strains which contain multiple attenuating mutations may also be used, so that the risk of reversion to a wild-type, virulent bacterium is vanishingly small.
Suitable attenuating mutants may be, for example, auxotrophic. Mutants with altered virulence factors may also be used.
One mutant strain which can be made by the site-directed mutagenesis method disclosed is one which is HsoI restriction endonuclease negative. Such a strain is useful for genetic engineering in H. somnus. Such a strain can be a recipient of DNA which is not HsoI methyl transferase methylated, yet would yield DNA which is HsoI methyl transferase methylated.
A preparation of isolated HsoI endonuclease can be prepared inter alia by passing a cell-free lysate of H. somnus over a column of heparin-sepharose. Other known techniques for isolating restriction endonucleases can be used as is appropriate. Typically the specific activity of such a preparation will be enriched as compared to the cell-free lysate.
The present invention thus allows those of ordinary skill in the art to stably introduce DNA into H. somnus. The DNA can be from other strains or species. The DNA can be artificially modified or in its native state. If recombination into the genome is desired two regions of flanking homology are preferred. Such techniques are generally known for other bacteria, but have been hitherto unsuccessful in H. somnus due to its restriction system.
Vaccines are typically formulated using a sterile buffered salt solution. Sucrose and/or gelatin may be used as stabilizers, as is known in the art. It is desirable that the Pasteurellaceae vaccines of the invention be administered by the intranasal or intratracheal route, but subcutaneous, intramuscular, intravenous injections also may be used. Suitable formulations and techniques are taught by Kucera U.S. Pat. No. 4,335,106, Gilmour U.S. Pat. No. 4,346,074, and Berget U.S. Pat. No. 4,957,739. Typically, between 10 7 and 10 11 CFU are administered per dose, although from 10 5 to 10 3 CFU can be used. Adjuvants also may be added.
EXAMPLES
Example 1
Plasmid Construction and Mutagenesis
The 4.2 kb plasmid (pD70) which encodes streptomycin resistance in Pasteurella haemolytica serotype 1 has been previously sequenced and described (Chang, Tatum). The plasmid was linearized by HindIII digestion and made blunt by treatment with dNTPs and Klenow fragment. A kanamycin cassette (Genblock) previously digested with BamHI and made blunt as above was ligated into pD70 to produce pD70kan. This plasmid was amplified in E. coli DH10B containing PhaI methyltransferase on cosmid PhaImtase. The plasmid was introduced into P. haemolytica strain NADC-D153. Plasmid DNA (1 ug) recovered from a kanamycin-resistant transformant was mutagenized with hydroxylamine for 90 minutes at 70° C. as previously described. The treated DNA was dialyzed against TE, ethanol-precipitated, and resuspended in TE (10 mM Tris, 1 mm EDTA, pH 8.0).
Example 2
Recovery of Temperature-Sensitive Plasmids.
Pasteurella haemolytica serotype 1, strain NADC D153, was grown to late logarithmic phase in 100 ml columbia broth at 37° C. with gentle shaking. The bacteria were pelleted by centrifugation at 5000 x G and washed in 100 ml 272 mm sucrose at 0° C. The pellet was resuspended in an equal volume of 272 mm sucrose at 0° C. Competent cells (100 ul) were placed into six 0.1 cm electroporation cuvettes and mixed with 100 ng of the treated DNA. The cells were electroporated (Gene pulser, Bio-Rad) at 18,000 V/cm and 800 ohms yielding time constants ranging from 11-12 msec. Immediately after each electroporation the cells were resuspended in 1.0 ml columbia broth at 0° C. Recovery was for 2 hours at 30° C. The suspension was spread (100 ul/plate) onto columbia agar (Difco) plates containing 50 ug/ml kanamycin. Plates were incubated 28 hours at 30° C. then transferred to 42° C. for 6 hours. Colonies were picked which were smaller than typical colonies and dotted onto kanamycin plates. After overnight incubation at 30° C., growth from each selected colony was duplicated onto columbia agar plates with and without kanamycin and then incubated overnight at 42° C. Growth from non-selective plates was transferred to kanamycin plates which were incubated overnight at 30° C. Clones which failed to grow with selection at 42° C. but which grew well on selective media at 30° C. after passage without selection at 42° C. were presumed to be temperature-sensitive for kanamycin expression. Similar clones which exhibited reduced growth on selective plates at 30° C. after passage without selection at 42° C. were presumed to be temperature-sensitive for plasmid maintenance. Four of the latter clones were selected for further study.
Example 3
Testing of Temperature-Sensitive Plasmids
Plasmid DNA was recovered by an alkaline lysis procedure from four P. haemolytica clones presumed to contain temperature-sensitive plasmid origins of replication. The DNA was electroporated into P. multocida strain NADC TT94, a bovine lung isolate which is Carter-Heddleston type A:3. After specific methylation with HhaI (as previously described) the DNA was electroporated into H. somnus strain HS91, a bovine lung isolate. Transformants were grown overnight on columbia agar plates supplemented with 5% bovine blood and 50 ug/ml kanamycin at 30° C. in 10% CO 2 . Duplicate broth cultures were inoculated with transformants of each organism and plasmid. One culture was grown overnight at 40° C., the other at 30° C. Plasmid was recovered from each broth by an alkaline lysis procedure and resolved on 1% agarose gels. Selective and non-selective plates were struck for subjective assessment of percentage CFU resistant to kanamycin after passage.
Example 4
Properties of the Replication-Conditional Plasmid
Pasteurella haemolytica was transformed to kanamycin resistance by the mutagenized plasmid at an efficiency of about 6×10 4 CFU/ug DNA. Of the transformants, about 1% (360) were found to form atypically small colonies after the incubation at 42° C. Passage of these colonies at either 30°C. or 42° C. on plates with or without kanamycin revealed that about 90% of the transformants were temperature sensitive for expression of kanamycin-resistance (about 10% failed to grow on the first passage and were not tested further). These organisms formed colonies on selective or non-selective plates at 30° C. but failed to grow on selective plates at 42° C. Passage of growth from non-selective plates at 42° C. to selective plates at 30° C. resulted in heavy growth, indicating plasmid was still present. A 5.5 kb plasmid was detected in plasmid preparations out of representatives of these cultures.
Ten of the 360 colonies behaved on passage similar to the colonies containing temperature-sensitive kanamycin genes except growth was reduced on selective media at 30° C. after passage without selection at 42° C. These colonies appeared to vary in percentage resistant to kanamycin after passage without selection at 42° C., indicating possible differences in their degree of instability at non-permissive temperature (42° C.). Four were selected based on their low yield of kanamycin-resistant colonies after passage without selection at the non-permissive temperature.
The four temperature-sensitive plasmids were readily introduced into P. multocida strain NADC-TT94 and into H. somnus strain NADC-HS91 (after appropriate methylation). The plasmids behaved as they did in P. haemolytica. No growth was observed on selective plates incubated at 40° C. and no plasmid was detected in broth cultures grown without selection at 40° C. Cultures transformed with wild-type plasmid grew well under selection at 40° C. and yielded plasmid DNA from non-selective broth cultures at that temperature. All cultures grew and yielded plasmid when grown with or without selection at 30° C. The results indicate that plasmid replication is temperature-conditional in each of the three species bacteria.
One of the temperature-conditional plasmids called pBB192 has been deposited in P. haemolytica NADC D153 at the American Type Culture Collection, Rockville, Md., 20852 under Accession No. ATCC 55893 on Dec. 2, 1996.
Example 5
Isolation and Characterization of Restriction Endonuclease, HsoI, from Haemophilus somnus and Protection of Heterologous DNA by HhaI Methyl Transferase.
Chromatographic fractions exhibiting endonuclease activity eluted from the heparin-sepharose columns by 680 and 760 mm NaCl (960-1060 μS). A single pass through these columns was sufficient to identify both the recognition specificity and cleavage site. Digestion of lambda DNA with the concentrated HsoI preparation resulted in a distinctive restriction fragment pattern identical to that produced by HhaI, a commercially available restriction endonuclease isolated from Haemophilus haemolytica. The cleavage site (5′. . . G↓CGC . . . 3′) was found to differ from that of HhaI, producing a 5′ overhang identical to that produced by HinPI.
Methods Used
Bacterium, growth, and crude extract.
Haemophilus somnus, strain 2336 (kindly supplied by Lynette Corbeil, San Diego, Calif.), was grown for 16 h on eight chocolate agar plates (Columbia blood agar base; Difco, Detroit, Mich., supplemented with 5% defibrinated bovine blood at 90 C, 200-ml total volume). The cells were harvested in TE (10 mm Tris, 1 mm EDTA, pH 8.0), pelleted by centrifugation at 16,000 x g for 5 min at 4 C, and washed once in TE. The washed pellet was resuspended in 12 ml chromatography running buffer (20 mm sodium phosphate, 10 mm 2-mercaptoethanol, pH 8.0, 0 C) and placed on ice. The bacterial cells were disrupted by sonication for 2 min in 15-s bursts. Debris and unbroken cells were removed by centrifugation at 16,000 x g for 10 min, and the supernatant was filtered through a 0.45-um-pore-size membrane (Millex-HA; Millipore Corp., Bedford, Mass.). No further treatment of the crude extract was performed prior to chromatography.
Chromatographic separation of proteins.
All chromatographic procedures were performed at room temperature. Prepacked heparin-Sepharose columns (Econo-pac heparin columns; Bio-Rad, Richmond, Calif.) were equilibrated as recommended by the manufacturer. A flow rate of 1.0 ml/min was used for separation, using a gradient low pressure automated chromatography system (Automated Econo-System; Bio-Rad, Richmond, Calif.). Five ml of crude extract was injected and a linear gradient from 0 to 1.0M NaCl in 60 ml of running buffer was used to elute proteins. Fractions (1 ml) were stored on ice prior to activity assay. A second identical chromatographic separation was performed with a new column from which active fractions were collected and pooled for storage.
Assay for restriction endonuclease activity.
Aliquots (5 ul) of the chromatographic fractions were incubated with 1 ul of React 1 (BRL, Gaithersburg, Md.) and 0.5 ul of unmethylated bacteriophage lambda DNA (0.5 ug/ul; New England Biolabs, Beverly, Mass.) at 37° C. for 2 h. After addition of tracking dye and electrophoresis on a 1% agarose gel in Tris-borate-EDTA buffer, the banding patterns were visualized by ethidium bromide staining and UV illumination. The fraction corresponding with DNA cleavage activity were pooled from the second chromatographic separation, concentrated 20-fold on 30,000-molecular-weight-cutoff ultrafilters, and brought to final concentrations of 150 mm NaCl, 10 mm sodium phosphate, 0.1 mm EDTA, 5 mm 2-mercaptoethanol, 0.25 ug of bovine, serum albumin per ml, and 50:50 (vol/vol) glycerol, pH 8.0, for storage at −20 C. The concentrated preparation was designated HsoI.
Determination of the recognition and cleavage sites for HsoI.
The recognition sequence was identified by digestion of pBluescript (Stratagene, La Jolla, Calif.) and of lambda DNA. The cleavage site was identified by digestion of a primed-synthesis reaction on pBluescript. An oligonucleotide primer was synthesized which is complementary with sequences 3′ from an HsoI site of pBluescript. Single-stranded DNA was used for the template. Standard dideoxy DNA sequencing reactions were performed and an additional reaction containing no dideoxy terminator was extended through the HsoI site with the Klenow fragment of DNA polymerase I by using 32 P-end-labeled primer. The extension reaction was stopped by phenol-chloroform extraction followed by ethanol precipitation. HsoI or HhaI (New England Biolabs) was added to the additional reactions and allowed to digest the DNA for 2 min. The reaction was stopped by addition of gel loading buffer and heating to 80° C. for 3 min.
Example 6
Transformation of H. somnus with Methylated DNA
DNA obtained from Haemophilus somnus or from E. coli and in vitro methylated with HhaI methyl transferase was resistant to cleavage by both HsoI and HhaI. Protection by in vitro methylation was found to often be partial, based on electrophoretic mobility of DNA after digestion with and without prior in vitro methylation, even when the substrate DNA had been phenol-chloroform-isoamyl alcohol extracted and then purified by CsCl gradient centrifugation.
Introduction of plasmid DNA into Haemophilus somnus was enhanced about 4 orders of magnitude by previous in vitro methylation of the plasmid. Each of the pD70-based plasmids transformed H. somnus, but efficiency dropped as the size increased. It is possible a second restriction-modification system may be responsible for the marked reduction in efficiency as plasmid size is increased. The possibility of systems analogous to mcr or mrr in E. coli was not investigated. Partial rather than complete protection conferred by in vitro methylation could also account for the reduction.
No ampicillin-resistant transformants were recovered, indicating either that the ampicillin-resistance cassette of pD80 does not express in H. somnus or that the origin of replication does not function. A pD70-based replicon containing the pD80 ampicillin-resistance cassette in the HindIII site transformed H. somnus to yield streptomycin-resistant colonies. Those colonies failed to replicate on ampicillin-containing media, indicating the ampicillin cassette does not function in H. somnus. The pD80 origin of replication was not tested further.
The kanamycin-resistance cassette derived from Tn903 was found to be excellent for selection of transformants. Streptomycin provided only fair selection. Transformants containing both streptomycin- and kanamycin-resistance cassettes were more robust on kanamycin selection than on streptomycin. Conversely, untransformed colonies were common on streptomycin selection but were not encountered on kanamycin selection.
A second strain of H. somnus, 649 (kindly supplied by Dr. Lynette Corbeil), was not transformed by derivatives of pD70. This strain was found to harbor a small plasmid which we presume to be incompatible with pD70. This plasmid, like pD70, might serve as a useful vector for the introduction of DNA into the bacterium.
The restriction-modification system carried by Haemophilus somnus are useful to genetically manipulate this pathogen. Specific methylation against the restriction endonuclease allows introduction of foreign DNA. Two replicons, both based on similar origins of replication, were discovered which may be of use as vectors for the introduction of foreign genes.
Methods Used
Construction and methylation of shuttle vector.
A derivative of pD70, the 4.2 kb streptomycin-resistance plasmid of Pasteurella haemolytica serotype 1, was previously constructed during experiments involving that bacterium. Briefly, the 2.2 kb PstI fragment of pD70 containing streptomycin-resistance was excised from a 1% agarose gel, electroeluted, and ligated with a PstI kanamycin cassette derived from Tn903.(Genblock, Pharmacia) The resulting plasmid conferred kanamycin-resistance in E. coli and in P. haemolytica. The plasmid was methylated with commercially available HhaI methyl transferase according to instructions. Other plasmids based on the pD70 origin of replication were tested, including intact pD70, pD70kan (pD70 with the kanamycin cassette blunt-ligated into the unique HindIII site), and pD80 (the 4.2 kb P. haemolytica plasmid encoding for ampicillin-resistance).
Electroporation of methylated DNA into Hemophilus somnus.
Haemophilus somnus strain NADC Hs91 (pneumonic bovine lung isolate) was grown in 100 ml Levinthol's broth at 37° C. in 10% CO 2 to late logarithmic phase, approximately four hours. The growth was pelleted by centrifugation at 5000 x G for fifteen minutes and washed once in 100 ml 272 mm sucrose at 0 C. The pellet was resuspended 1:3 packed bacteria: 272 mm sucrose on ice. Competent bacteria (100 ml) were mixed with 100 ng plasmid DNA either unmethylated or in vitro methylated in 0.1 cm electroporation cuvettes (Bio-Rad). The cells were quickly electroporated after addition of DNA (Gene pulser, Bio-Rad) at 18,000 V/cm, 800 ohm, 25 mFd with resultant time constants ranging from 11 to 15 msec. Levinthal's broth (1 ml, 0 C) was immediately added to the electroporated cells and the suspension was incubated at 25° C. approximately 10 minutes. The cells were then recovered at 37° C. with 10% CO 2 for 2 hours. Ten-fold dilutions were plated onto chocolate agar plates (Columbia blood agar base with 5% defibrinated bovine blood) containing 50 mg/ml kanamycin, 100 mg/ml streptomycin, or 20 mg/ml ampicillin. Colonies were enumerated after 36 hours incubation at 37° C. with 10% CO 2 . Representative colonies were examined for plasmid content using a rapid alkaline lysis procedure.
Example 7
Use of a Temperature Conditional Replicon to Generate an aroA Deletion Mutant of Pasteurella multocida
Previous attempts to produce gene-replacement mutants of P. multocida in our lab were hindered by poor electroporation efficiencies and by replication of ColE1-based replicons in P. multocida (unpublished results). In addition, products of gene-replacement typically contain foreign antibiotic resistance genes which may preclude or delay particular uses of otherwise desirable mutants. The shuttle plasmid constructed here was used to overcome those problems.
The origin of replication of the P. haemolytica plasmid pD70 was found to be within a 1.2 kb Sau3A1 fragment downstream from the streptomycin coding region. Together with a kanamycin cassette derived from Tn903, the vector (pBB192) proved to replicate in members of the Family Pasteurellaceae but not particularly well in E. coli, requiring cloning of sequences relying on the pD70 origin to be performed in a Pasteurellaceae host. While unsuitable for use in P. multocida, a derivative of the shuttle vector was constructed which contains a ColE1 origin of replication in the BamHI site (pBB192C) to facilitate construction in E. coli of temperature-conditional constructs for use in P. haemolytica or H. somnus target organisms (unpublished results). Plasmid pBB192C replicated efficiently in E. coli.
Approximately 100 P. multocida transformants were received on kanamycin at 30° C. from electroporation with 25 ng of replacement plasmid. Passage of broth cultures from 6 representative colonies to kanamycin plates at 40 C resulted in about 20 well isolated colonies from each 10 ul inoculum, but the number of colonies produced varied among the 6 cultures. The colony size varied significantly on each plate, yielding a number of small colonies and a few large colonies. The relative proportion of these sizes varied among the 6 cultures. Southern blot analysis of genomic DNA from the colonies (probing with aroA) revealed that the small colonies were products of single crossover events. The large colonies contained sequences homologous to aroA which were not similar in size to the replacement plasmid in addition to a fragment consistent with wild-type chromosomal aroA. The large colonies were not examined further. Our interpretation of the data is that the integrated replacement plasmid destabilizes the chromosome, resulting in a substantial reduction in replication rate and therefor conferring small colony size. The replacement plasmid, however, replicates so inefficiently by itself at the non-permissive temperature that colonies do not form at all under kanamycin selection. This situation put strong selective pressure to rearrange the plasmid for improved replication or to integrate into chromosome plasmid sequences containing the kanamycin gene, resulting in some potential unlikely products.
Passage of growth from products of single-crossover events without kanamycin selection resulted in >99% loss of kanamycin resistance in a single passage. These results indicate substantial instability of the single-crossover product. Among 500 isolated colonies from such a passage, 5 failed to grow on both defined medium and under kanamycin selection. Southern blot analysis confirmed the loss of DNA sequences homologous to the deleted ClaI-EcoRV fragment, failed to show homology with plasmid vector, and showed a reduction of about 300 bp in size of chromosomal aroA. Results of PCR analysis indicated a 300 bp reduction in product size. Sequencing of the PCR product confirmed a deletion extending from the EcoRV site to slightly beyond the ClaI site, 5′-ATTGATAT-GAACCAT-3′, which does not alter the reading frame of downstream DNA sequences.
The temperature-sensitive shuttle vector separated the operations of bacterial transformation from that of selection of crossover products in gene-replacement. It also simplified the generation of products without foreign selectable markers. The instability of single-crossover products appeared to facilitate resolution of the plasmid from the chromosome to generate deletion mutants without use of negative selection afforded by such genes as SacB. Since the vector replicates temperature-conditionally in P. haemolytica and in H. somnus, it is likely that it should be equally useful in these or other Pasteurellaceae as well.
The P. multocida aroA mutant constructed here which was deposited on Dec. 2, 1996, at the ATCC, and given the accession number ATCC 55892, differs from that described by Homchampa et al because the present strain is of bovine origin, a deletion was introduced in aroA, and no foreign DNA sequences are present in the product. This mutant can be used as an attenuated live vaccine.
Methods Employed
Construction temperature-sensitive shuttle vector.
A shuttle-vector was constructed based on the previously described temperature-sensitive origin of replication of pD70, the streptomycin-resistance plasmid isolated originally from P. haemolytica serotype 1 (Tatum et al, Chang). A PCR product approximately 1450 bp was produced from temperature-sensitive pD70kan #192 using forward primer 5′-GCCTGTTTTTCCTGCTC-3′ and reverse primer 5′-CCTGCGGTGTAAGTGTTATT-3′. The product was digested with Sau3A1 to completion to produce an approximately 1.2 kb fragment. A kanamycin resistance cassette from Tn903 (GenBlock, Pharmacia) was digested with EcoRI, ligated into the EcoRI site of pBC SK (Stratagene), and electroporated into E. coli strain 30-9G to produce PhaI-methylated plasmid DNA (Briggs et al). The approximately 1.3 kb kanamycin-resistance cassette was excised from the methylated plasmid with BamHI and ligated overnight to the 1.2 kb Sau3A1. The ligation mixture was electroporated into P. haemolytica strain NADC-D153 and plasmid was recovered from kanamycin-resistant colonies. It was found that a portion of the pBC SK multiple cloning site from the EcoR1 site to the BamHI site had been transferred along with the kanamycin cassette, resulting in a 2.5 kb plasmid with a unique EcoR1 site and an effectively unique BamHI site which replicates in P. haemolytica, P. multocida, and H. somnus at 30° C. but very poorly in E. coli. The plasmid was named pBB192.
Cloning and deletion of P. multocida aroA.
A 1.2 kb PCR product containing the aroA gene was produced using forward primer 5′-TTACTCTCAATCCCATCAGCTATA-3′ and reverse primer 5′-CTATCTGTAGGCTACTTCGCGTG-3′. The product was cloned into a vector which contains EcoR1 sites flanking the PCR product insert (TA vector, Invitrogen). The insert was excised with EcoR1 and ligated into the EcoR1 site of puC9. The product was double digested with ClaI and EcoRV to remove an approximately 300 bp fragment. The ends of the remaining plasmid were made blunt using Klenow fragment of DNA polymerase I and dNTPs then ligated upon themselves to generate a deletion of aroA. The deleted plasmid was amplified in E. coli strain 30-9G to PhaI methylate the DNA then digested with EcoR1 and electrophoresed on an agarose gel to confirm the deletion. The PhaI-methylated EcoR1 aroA fragment containing the deletion was ligated into the EcoR1 site of pBB192 to create pBB192PmΔaroA. The ligation mixture was electroporated into P. haemolytica strain NADC-D153 and plasmid was recovered from kanamycin-resistant colonies.
Production of P. multocida single-crossover products.
Pasteurella multocida strain NADC-TT94, a bovine lung isolate of Carter-Heddleston type A:3, was grown 4 hours in 100 ml columbia broth containing 2,500 U hyaluronidase. Growth was centrifuged at 5000 x G for 15 minutes and washed twice in 272 mm and sucrose at 0° C. then resuspended in 1 ml 272 mm sucrose. The cells (100 μl) were electroporated (Gene Pulser, Bio-Rad) with 25 ng pBB192PmΔaroA in a 0.1 cm cuvette at 1.8 kv, 800 Ω, and 25 μF with a resultant time constant of 14.7 ms. The cells were immediately resuspended in 1 ml columbia broth at 0° C. then incubated for 2 hours at 30° C. The recovered cells were spread 100 ul/plate on columbia agar plates containing 50 μg/ml kanamycin then incubated 24 h at 30° C. Six colonies were passed separately to 5 ml columbia broth containing 50 μg/ml kanamycin which were incubated 18 hours at 30 C. Growth was spread (10 p/plate) onto columbia agar plates with kanamycin which were incubated 24 hours at 40 C. Representative colonies were passed to columbia broth (25 ml) with kanamycin (to confirm single crossover products by Southern blot analysis) and to columbia broth (5 ml) without kanamycin (to screen for deletion mutants) and incubated overnight at 40 C.
Screening for P. multocida deletion mutants.
From the non-selective broth culture above, columbia agar plates were struck for isolated colonies and incubated overnight. Five-hundred isolated colonies were passed into microtiter plates containing 100 μl columbia broth/well and incubated 6 hours. Growth (1 μl) was passed into each of two microtiter plates containing either 100 μl/well columbia broth with kanamycin or 100 μl/well chemically defined medium lacking tryptophane based on that of Wessman et al and that of Watko et al. Wells which grew only on the original non-selective microtiter plate but not on either kanamycin or defined medium were suspected deletion mutants. These were passed for Southern blot analysis and for PCR analysis using forward primer 5′-CTACCCACCTATCGCCATTC-3′ and reverse primer 5′-TCCGCCCCCACCTTA-3′. The PCR product from one of the deletion mutants was cloned for sequencing of the deletion.
7
15 base pairs
nucleic acid
single
linear
DNA (genomic)
NO
NO
PASTEURELLA MULTOCIDA
aroA-
1
ATTGATATGA ACCAT 15
17 base pairs
nucleic acid
single
linear
DNA (genomic)
NO
NO
Pasteurella haemolytica
serotype 1/pD70
2
GCCTGTTTTT CCTGCTC 17
20 base pairs
nucleic acid
single
linear
DNA (genomic)
NO
NO
Pasteurella haemolytica
serotype 1/pD70
3
CCTGCGGTGT AAGTGTTATT 20
24 base pairs
nucleic acid
single
linear
DNA (genomic)
NO
NO
Pasteurella multocida
NADC-TT94
4
TTACTCTCAA TCCCATCAGC TATA 24
23 base pairs
nucleic acid
single
linear
DNA (genomic)
NO
NO
Pasteurella multocida
NADC-TT94
5
CTATCTGTAG GCTACTTCGC GTG 23
20 base pairs
nucleic acid
single
linear
DNA (genomic)
NO
NO
Pasteurella multocida
ATCC 55892
6
CTACCCACCT ATCGCCATTC 20
15 base pairs
nucleic acid
single
linear
DNA (genomic)
NO
NO
Pasteurella multocida
ATCC 55892
7
TCCGCCCCCA CCTTA 15 | Tools for genetically engineering Pasteurellaceae are provided. Replication-conditional plasmids which are useful for the Pasteurellaceae have been isolated and characterized. The plasmids can be utilized for delivery of DNA segments into the Pasteurellaceae in situations where control of extra-chromosomal replication desired, such as in achieving allelic exchange or site-directed mutagenesis.
A restriction endonuclease, HsoI, was isolated from a bovine lung isolate of Haemophilus somnus. The enzyme was found to be a true isoschizomer of HinPI, a commercially available enzyme originally isolated from Haemophilus influenzae PI. Commercially available HhaI methyl transferase was found to protect against cleavage by both enzymes. Methylation of foreign plasmid DNA was found to enhance transformation of Haemophilus somnus in excess of four orders of magnitude. | 2 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is an U.S. national phase application under 35 U.S.C. §371 based upon co-pending International Application No. PCT/NO2006/000345 filed on Oct. 6, 2006. Additionally, this U.S. national phase application claims the benefit of priority of co-pending International Application No. PCT/NO2006/000345 filed on Oct. 6, 2006. The entire disclosures of the prior applications are incorporated herein by reference. The international application was published on Apr. 10, 2008 under Publication No. WO 2008/041856.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a platform which produce electric power, more specific an oil or/and gas producing platform holding its own power plant on one of its upper decks.
[0004] 2. Description of the Prior Art
[0005] Productions of hydrocarbons (oil and gas) is normally done through concepts consisting of platforms either floating or standing on the seabed or by use of special purpose built ships.
[0006] Today power plants are positioned onshore with a fuel supply from a hydrocarbon source. This source could be either through a pipeline from a platform or it could be from a hydrocarbon storage facility nearby. The energy generated by the power plant is then transported across a power energy network to the end user.
[0007] One of the negative aspects of power plants using hydrocarbon fuel today is the CO2 outlets through the exhaust. Today it is known that CO2 gas influence the weather and temperature and thus a threat to the environment. The handing of CO2 has become an expensive and difficult task to clean before the exhaust fumes can be let out into the air. Furthermore, it is very expensive to transport hydrocarbons from an oil producing facility offshore to an onshore facility either through permanent pipelines or by vessel and thus contribute considerably to the cost of producing electric power using hydrocarbons.
SUMMARY OF THE INVENTION
[0008] Thus, the main objective with present invention is to provide an offshore platform which is constructed with an eye to reduce the cost of transporting hydrocarbons on shore and getting rid of C O2 gas without adding it to the atmosphere and causing further environmental problems. This is achieved with the platform according to present invention as it is defined in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] 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:
[0010] FIG. 1 is a cross section of a separate module.
[0011] FIG. 2 is a horizontal cross section of a completed platform.
[0012] FIG. 3 is a vertical cross section A-A of the platform showing the circular columns partly filled with oil or ballast.
[0013] FIG. 4 is a block diagram of an additional process on the platform which will be carried out in connection with the power plant.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] With reference to FIGS. 1 , 2 , 3 and 4 . A platform 10 according to the invention will consist of a circle of modules 1 , each module consisting of at least one of circular column 2 , with the same or different size of diameter, surrounded by concrete to create a desired outer surface. The straight sides 3 , 4 of the module will have an angle [alpha] given by the number of modules 1 the platform 10 shall consist of and thus giving the size of the platform. The modules will be held together by some fixing means, like bolts or similar. The internal circular “column” 5 generated by the modules 1 in the middle of the platform 10 can be either sealed at the bottom and be used for storage of oil, gas, etc. or nothing, or completely filled with the water surrounding the platform. The modules may be put together in a sealing way so that the central space of the platform can be utilized as desired. The production of a module 1 is based on the Norwegian patent 162 255 for building bridges submerged in water (fresh or sea water). The Norwegian patent 162 255 describes a method for producing these circular columns 2 in a rational and economical way. However, the method is not essential for the end result, so other methods available can be used. When all the modules 1 have been produced and put in place to create the complete platform 10 , it is then taken offshore, positioned and either lowered down to the seabed on top of one or more production wells for oil and or gas, anchored in position like a floating vessel/platform, or “tied” down like a tension-leg platform.
[0015] The production of this type of platform 10 is much cheaper than the method used for known platforms like a Condeep where the use of a sliding frame which is moved in the vertical direction which results in a higher cost and more difficult process of providing concrete at a steady pace. The known techniques for such sliding frames require high level of man power compared to the technique described in the Norwegian patent 162 255.
[0016] As the modules 1 are produced they are simply turned 90[deg.] into a vertical position and put in the respective radial position until the platform 10 has reached its final dimension/size.
[0017] Some of the advantages with this type of platform relative to the known concepts utilized today are, a) expansion chambers (i.e. one of the circular columns 2 ) can be utilized in stead of a flare system, b) the internal volume of the platform makes it possible to utilize passive separation for separation of production water, and c) through the vertical circular columns 2 it can be carried out dry drilling (i.e. not subsea/subwater drilling) which reduces the danger for uncontrolled blowouts. Any leakage in or collapse of one or more of the circular columns 2 will not necessarily be critical for the platform 10 when it comes to lack of buoyancy etc., because of the number of circular columns 2 the platform 10 consist of.
[0018] On at least one of the deck 6 to the platform 10 there will be a processing plant adapted to the type of hydrocarbons being produced, in addition to the power plant. The oil and/or gas which normally would have been transported either by a vessel or by a pipeline to an oil refinery/storage facility onshore will now be fed to an onboard storage tank. This storage tank could be at least one or more of the vertical circular columns 2 . When the oil/gas are placed in one or more of these columns at a high temperature, a natural horizontal separation will take place in that or those columns 2 , hereafter referred to as the separation tank 12 .
[0019] The different quality of hydrocarbon will be used for specific engines suitable for that type of fuel. The engines will drive a generator to produce electric power. In the separation tank 12 will sand and/or debris 13 be taken out and deposited. Any water from the production, production water 14 , will be drained out and used for reinjection 24 . The power production can be carried out by use of different type of engines 18 . However to simplify the description we have only described the process by use of diesel engines, but the process would be the same with the use of other types of engines.
[0020] With reference to FIG. 4 . Oil and/or gas 11 from the oil well are allowed to separate in the separation tank 12 . Sand/debris 13 and production water 14 is taken out from the separation tank 12 . The separated oil and gas 15 is lead to the process plant 16 on the platform for production of fuels which are stored in the fuel tanks 17 . The fuel for the diesel engines will be taken from the fuel tank and supplied to the diesel engines 18 . The diesel engine cooling water 19 and exhaust gas 20 will be used to heat up the production water 14 . When the exhaust gas have been through a dry filter 21 to remove debris, the exhaust gas 20 and the production water 14 are put under high pressure by a compressor 22 for injection 24 . By adding the exhaust gas 20 and the temperature transfer 23 from the cooling water 19 of the diesel engine 18 to the production water 14 will combined create very high efficiency when injected back into the reservoir. The advantage with this method is that the mixture of water and oil remnants 14 together with the exhaust gas 20 which include CO2, having a high temperature, will better dissolve the oil and gas within the reservoir when injected.
[0021] However, the most important reason for returning the exhaust gas 20 is that it would be deposited in its entirety at a low cost and the withdrawal from the reservoir will be increased. This process is feasible because the present invention has a very large storage capacity. No other platform today has this opportunity.
[0022] Another advantage with the present invention is that there exists no need for transportation of the hydrocarbons to an onshore facility, either through pipelines or by use of vessels. The distribution network for electric power is much cheaper to install and do not hold such a threat environmental pollution as a pipeline or vessel do. | Platform for a power plant equipped for producing oil and made of reinforced concrete to reduce maintenance cost, consisting of at least one module. Each module will consist of at least one circular column surrounded by concrete to create a desired outer surface. Any of the columns can be used to store the petroleum (oil, gas, production water, sand, etc.), act as expansion chamber(s) and act as passive ballast or separation tank. The platform will have at least one deck for oil producing equipment, at least one deck for a power plant, and will have equipment necessary for electric power distribution. | 4 |
PRIORITY CLAIM
[0001] This application is based on, and claims the priority of, PCT International Application No. PCT/IN2004/000368 Filed on Nov. 29, 2004.
TECHNICAL FIELD
[0002] This invention of automatic sunlight redirector comprises of a device which redirects sunlight to a place of user's choice by arranging incident sun-ray, target-line and the mirror-axis as sides of an isosceles triangle.
BACKGROUND OF THE INVENTION
[0003] In the last three decades solar energy has been recognized as a potential source of energy for various purposes. The two known manifestations of solar energy—namely light and heat are being converted in to useful energy. Light is converted in to electricity through photo-voltaic cells and heat is either being used for heaters or for generating electricity through thermal power plants.
[0004] It is common knowledge that photo-voltaic power generation in spite of all its advantages is very costly option. For this reason, the progress in this area has not been quite impressive.
[0005] In countries between 45 degree north and 45 degree south latitude, sunlight is quite rich and it can be harnessed for many purposes including lighting of the interiors of the buildings. This is done through passive reflectors and glazed windows/roofs. Some active sun-tracking devices have also been invented which can send light into the interiors. For redirection of sunlight into interiors very accurate sun-tracking is essential. However, as yet no device has been invented which can help harnessing solar energy to fuller extent at affordable price for individual users for domestic purposes or for small requirements. The cost of machines is high because movements of the sun during the day and during the year are very complicated and defy any simple mathematical formulation capable of being translated into mechanical device, and therefore help of costly computers and sensors etc. have to be taken for sun-tracking.
Importance of Sun-Tracking
[0006] Solar energy begins to shower on the earth as soon as the sun appears on the eastern horizon. Its intensity increases until noon, then it begins to decrease until sun sets in the west. This variation is due to angularity of the sun-beams in relation to the surface of the earth. In the morning the sun-rays have to pass through greater layer of air and dust particles; also each unit area of sun-beam falls on larger area of earth-surface due to this angularity.
[0007] While nothing can be done to reduce the layer of air and dust, human effort can help in catching larger amount of sunlight by keeping the receiver perpendicular to the sun-rays. This activity of moving objects according to the movement of the Sun is known as sun-tracking. Owing to its importance various types of sun-tracking devices have come into existence.
[0008] By sun-tracking, not only the output of the system increases but also some activities like producing high temperature become possible.
Problems in Sun-Tracking
[0009] Sun tracking is very complex affair for following reasons:
[0000] 1) Sun changes its route everyday throughout the year.
2) Sun takes different time every day during the year to travel from eastern horizon to western horizon.
3) Both the route and the timing vary from place to place even on the same day of the year. Apart from these simple problems, there are some much more complex problems which are narrated later.
[0010] Therefore no simple mechanical device could be designed so far which could help in following the route of the sun at every place in the world—this has precluded large scale production of a mechanical device which could be universally useful.
[0011] For sun-tracking the object e.g. a mirror, sought to be sun-oriented has to be moved in the direction of the sun. This can be done by fixing the mirror on a machine moving on north-south axis and rotating from east to west. The object is oriented towards sun at sunrise. Then with the climbing of the sun the machine is to be rotated from east to west.
[0012] When such a simple rotation is given, it is observed that the mirror does not follow the route as explained below because except on equator the sun moves not only westward but also north-south-north-ward also.
[0013] A probable solution is to move mirrors slowly towards south also, from sunrise to noon. So there is a necessity for following information, and a device to achieve this:
[0000] 1) Angle of deviation from east at sunrise.
2) Angle of elevation of the sun at noon.
3) Time taken by the sun to traverse from horizon to reach noon position.
4) A device to move the mirror both westward and southward at the required speed calculated from the above three information.
[0014] But unfortunately such arrangement will not work on next day because all 3 factors namely:
[0000] 1) Angle of deviation from east at sun rise,
2) Angle of elevation of the sun at noon and
3) Time taken by the sun to traverse from horizon to reach noon position, will be different every day. So the information for all the 365 days of the year have to be at hand and the mirror-rotating device has to be programmed for these different movements and for different timings.
[0015] This is a horrible work. Unfortunately, even if such a machine is built, it will be useful only for that particular place. It will not work at a place with different latitude. For this reason no device could be invented which can have simple function and universal application. Therefore, electronics-supported costly systems were opted by large-scale users of solar energy and nothing could be done for small users.
[0016] One can imagine the problem of reflecting light on a point of one's choice when sun-tracking itself is a tough task. This is so because for reflecting light, not only the sun is to be tracked but the mirror has to be moved such that the light is always reflected on the desired place while the angle of incidence and reflectance are changing every moment as shown in FIG. 5 .
Prior Art
[0017] As mentioned earlier, owing to the complexities of the movement of the Sun no mechanical device could be built which could track the Sun and redirect sunlight on desired target on each day of the year and at each place in the world at a price affordable to a small-scale user.
[0018] With the advancement of Science and Technology and efforts of inventors, many systems have come into existence for reflecting light on user's choice. This is being done today with the help of computers. Obviously these systems are very sophisticated and costly, therefore they are not becoming popular. There are also some machines which can send sunlight into the kitchen for cooking. These machines have a parabolic mirror, which rotates on polar-axis and sends light along this axis into the house. They cannot send light to any point of users' choice. This limitation coupled with high cost and unsuitability to lifestyle has precluded its acceptability to the users. This machine can be used for daylighting also but with the above limitations.
SUMMARY OF THE INVENTION
[0019] The problems mentioned above have been solved by the device of the present invention. The advantages of the machine are as follows:
[0000] 1) It can be operated manually, through torque of spring or by electricity.
2) It is a universal model.
3) It can reflect light on any point of users' choice, thereby making possible—solar-cooking inside the kitchen, heating and day-lighting of the buildings etc. This can also be useful for increasing the output of the costly photo-voltaic panels by using multiple reflectors and supplying greater amount of sunlight on the panels. It can also help for its security against winds etc. as the panels can be housed inside lock and key while receiving light through a window etc.
4) Its functioning is very simple and with a very limited training one can be able to install, operate or repair the machine.
5) Its cost is low.
DISCLOSURE OF THE INVENTION
[0020] The present invention has been devised to reflect sunlight at a point of user's choice for daylighting, heating etc. This has two parts namely sun-tracking part and the reflector part. Sun-tracking part is based on polar-axis tracking with novel features to make it a completely automatic system.
[0021] The present invention has a declination-setter which automatically sets the sun-tracking-bar according to the declination of the sun for the day of operation, and thereby does away with the two-axis tracking to cope with the north-south-north movement of the sun during the day or the trouble of adjusting for sun-declination in the polar-axis tracking.
[0022] The present invention has arrangement for starting of the machine at a particular time of the day through time-setter. This has advantage over the sensor-based systems, which have problem if the morning is cloudy and the light lining is far away from the actual point of sunrise. This has advantage of not only cost but also of simplicity over the computer-data-software based systems because their data and software are place-specific; also in the present invention there is absolutely no necessity of calculating angle of reflectance for the mirror—the machine performs both the jobs simultaneously—the sun-tracking and the redirection of sunlight on the desired target area.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 generally illustrates a side perspective view of the light machine of the present invention.
[0024] FIG. 1 a generally illustrates a side perspective view of a declination-setter device of the light machine.
[0025] FIG. 2 generally illustrates a side perspective view of a detailed portion of the light machine.
[0026] FIG. 3 generally illustrates the movement of the sun around the Earth.
[0027] FIG. 4 generally illustrates the change of declination of the sun at local noon.
[0028] FIG. 5 generally illustrates the change in the angle between the sun and the target.
[0029] FIG. 6 generally illustrates the time-disc mover of the present invention.
[0030] FIG. 7 generally illustrates the effect of a ray falling on the mirror of the present invention.
[0031] FIG. 8 generally illustrates the arrangement for reflection of light to the target area.
[0032] FIG. 9 generally illustrates the arrangement extension of the size of the mirror from the B to the F position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1.
[0033] This is perspective of the complete machine. The parts that need elaboration are separately shown in FIGS. 2 and 6 .
[0000] 01 Stand—to support the whole structure.
02 Base pipe—to hold revolving arc couple ( 3 ) and the shaft ( 7 -A)
03 Arc-couple—revolving on pipe ( 2 ). Free to move 360 degree, thereby, together with arc-couple (β) makes possible to move mirror in any direction and even then maintaining same distance between the pivot of director bar ( 10 ) and pivot of mirror-arm ( 12 ).
04 Axle—giving free movement to mirror arm ( 12 ) caused by sliding director-bar ( 10 ) in north-south-north direction when in operation.
05 Pipe-holding axle ( 5 -A). Axle ( 5 -A) fitted inside pipe ( 5 ) helps to give free movement to mirror-arm ( 12 ) caused by movement of director-bar ( 10 ) in the east-west direction when in operation.
06 Arc-couple—fitted on arc couple ( 3 ) with nut-bolt for adjusting the position vertically in the desired direction.
07 Arc—made of two arcs and having gap to allow its placing on the supporting rod ( 7 -A) such that the polar-axis-bar ( 9 ) can be placed on the position parallel to the axis of the earth.
08 Declination setter—This device automatically sets the director-bar according to the declination of the Sun on that day. It is described in details in the description of the FIG. 2 .
09 Polar-axis-bar—This is a rotating bar fitted on arc ( 7 ) on free bearings. This has to be placed parallel to the axis of the earth. This position is attained by bringing the rotating bar in geographical north-south line (alternately called meridian line) and then by moving it in vertical plain by an angle equal to the latitude of the place of operation, e.g. at a place at 30 degree north latitude, the northern end of rotating-bar will have to be moved upwards by an angle of 30 degree in relation to horizontal line. Director bar—When adjusted by the declination setter for the date of operation, and moved by the rotating bar it remains sun oriented. And as the movement of the Sun has two components namely east-west and north-south-north, the director-bar also moves accordingly. By its movement the director-bar moves the mirror-arm ( 12 ) to a position that it reflects sunlight on the target-area. Slide—Either spherical or cylindrical, fitted on the director-bar and sliding on groove on the mirror-arm ( 12 ), it helps to move the mirror-arm ( 12 ) in east-west and south-north-south direction. Mirror-arm—Holds mirror and is moved by the slide ( 11 ) fitted on the director-bar ( 10 ). This has free movement in two directions because of free axles ( 4 ) and ( 5 -A). Timer—Moves the rotating bar at a speed of one round every 24 hours. This starts working as soon as the alarm-clock sends the message to start operation and continues to move the polar-axis-bar ( 9 ) until the alarm-clock sends the message to stop and come back to the original position for the next morning. The original position for the next day would be different and would be taken care of by the time-setter. Orientation-Bar-disc—The bar of this bar-disc is virtually extension of the director-bar ( 10 ). It is to be fitted on the free end of the director bar ( 10 ) passing through the mirror-arm ( 12 ). There is a disc between the director-bar ( 10 ) and this bar. When the director-bar ( 10 ) is moved such that there is no shadow of this bar on the disc, it is ensured that the director-bar is sun-oriented. This helps in making the director-bar ( 10 ) sun-oriented if the machine is to start operation during any time of the day after installation or after repair of the machine. Time setter—It is attached with the arc ( 7 ) on a metal-plate. The user may fix the time for starting of the machine automatically with the help of this component and an alarm-clock ( 16 ). This time-setter is described in detail in the description of FIG. 6 . Alarm-clock—This is an electronically programmed alarm-clock which sends the message to the timer ( 13 ) to start and end the working at a specified time everyday. The user has an option to program the starting and ending of the movement of timer-motor ( 13 ) as per his choice through electronic circuits {these circuits may be used to bring back the director bar ( 10 ) to the position of next day immediately after stopping of the timer at the end of the day).
FIG. 2.
[0034] This is declination-setter device for the director-bar described above as ( 10 ) in FIG. 1 and has following components:—
[0000] 1 . This is a rotating bar named as declination-bar fitted on a steel frame. There is a hole at the center of the bar through which passes another small bar. On this small bar a U-shaped clamp is fitted and on this clamp another bar is fitted which is connected on the other end with the circular strip ( 3 ) such that the circular movement of the strip ( 3 ) forms a cone of 23.5 degree having its vertex on the center of this declination-bar ( 1 ).
[0035] On this declination-bar ( 1 ) is fitted the director-bar described as ( 10 ) in the FIG. 1 . When circular strip ( 3 ) is moved one full circle by movement of the gear ( 6 ) it gives all the angles to declination-bar ( 1 ) which the Sun forms with the earth axis during one year, and the director-bar thereby is adjusted to the position for each day of the year.
[0000] 2 . This bar connects the free moving clamp to the circular strip ( 3 ) and makes a cone of 23.5 degrees when rotated by the movement of the calendar-disc described in ( 6 ) below and may be named as coninq-bar.
3 . This circular strip is a part of a virtual circle which is formed having its center on the center of the axis of the declination-bar ( 1 ). The bar ( 2 ) is fastened on this strip in a hole at a distance of 23.5 degree from the pivot of the circular strip.
4 . This is a freely moving pivot-axle fitted through a strip which is fitted on the frame parallel to the rotating-bar ( 1 ). On one side of this pivot is fitted the circular strip ( 3 ) and on the other side is fitted another strip ( 5 ).
5 . This strip has a hole on which a small nail is inserted, which nail is fitted on the toothed disc ( 6 ).
6 . This is toothed disc fitted on a pivot that is eccentric in relation to the pivot ( 4 ) to the extent that its movement equal to 177.2 degree causes a movement of the strip ( 5 ) equal to 180 degree during one half of its movement, and in its second half of the movement its 182.8 movement causes 180 degree of the movement of strip ( 5 ). The movement of the strip ( 5 ) is caused due to fastening of the nail fitted in the gear-disc ( 6 ) and fastened on the hole of strip ( 5 ). This gear-disc is moved by a motor at a speed of one round every 365.25 days. This disc may be used as a calendar if suitably the dates are marked on the circumference of the disc; these markings can be useful for installation of the machine. Then this disc may be named as calendar-disc.
7 . This is a motor for moving calendar-disc ( 6 ) at a speed of one round every 365.25 days.
FIG. 3
[0036] Shown in FIG. 3 is the movement of the earth around the sun
FIG. 4
[0037] Shows the change of declination of the sun at local noon
FIG. 5
[0038] Shows the change in the angle between the Sun and the target FIG. 6 .
[0000] 1 . Timer—This moves time-disc-mover ( 2 ) at a speed of one round per year.
2 . Time-disc-mover—This disc has marking for each day of the year and fitted on one side of the time-setter-plate ( 4 ) and fitted firmly with the time disc ( 3 ) with an axle passing through the base-plate ( 4 ). When moved by the timer it moves time disc through the common axle between itself and time-disc ( 3 ).
3 . Time-disc—This has varying radius corresponding to each date of the time-disc mover.
4 Time-setter-base-plate—On this all components of time-setter except ( 6 ) and ( 7 ) are fitted.
5 Time point—This is a flat square shaped thick plate sliding on a groove fitted on time-setter-base-plate. It is so fitted that one of the two opposite corners touches the time disc ( 3 ) and on its other corner time bar ( 6 ) rests after the end of the day to begin working at the appointed time as per users choice. This point is shifted by the movement of the time-disc because of its varying radius for each day.
6 Time-bar—This is fitted on a co-axial pipe on the rotating bar numbered in Rg-I as ( 9 ) whose cross section is represented by ( 7 ) and which is fitted on that position of the rotating bar according to the desire of the user for the starting time of the machine.
7 This is cross section of the polar-axis-bar. FIG. 7-A shows the effect of a ray falling on the mirror
FIG. 7-B shows an isosceles Triangle ABC
FIG. 7-C , is an isosceles triangle ABC where sides AB and AC are equal.
FIG. 7-D shows the shift of position C in an isosceles triangle due to fixature of BA and sun orientation of AC.
FIG. 8 Shows the arrangement for reflection of light to target area
FIG. 9 Shows the arrangement extension of the size of the mirror from B to F position
BEST MODE FOR CARRYING OUT THE INVENTION
[0039] The invention machine performs two operations, namely it tracks the Sun and it redirects sunlight on a fixed point throughout the day from where it can again be redirected to where it is needed. Obviously the invention machine has to be in two parts, one for sun-tracking and the other for redirection of sunlight. Since the sun-tracking part is subservient to the redirection system the redirection system is being described first.
Part-1: Redirection-System.
[0040] As narrated earlier the sun-tracking itself is a very complicated work and therefore computers have been put to service for the purpose. When the light is to be reflected/concentrated within the system a good sun-tracking system is sufficient because a concentrator can be fitted in the system which can be kept sun-oriented and the sun-rays get concentrated on the focal point of the concentrator. But when the light is to be reflected on a point outside the system the job becomes still tougher, because as shown in figure ( 5 ) angle of incidence of sunlight and therefore, the angle of reflectance also goes on changing every minute of the day and therefore this new factor is to be taken care of, in addition to locating the position of the Sun. Looking to the complexity of the problem, in the existing systems, help of computers is being taken.
[0041] The invention takes into consideration the principles of reflection of Light, basic geometry and the mechanics as explained below:—
1. Reflection of Light:
[0042] As per the principles of Optics when a ray falls on the mirror the angle between the incident ray and the reflected ray is divided equally by a perpendicular on the mirror at the point of incidence as shown in the figure ( 7 - a ). 2. Principles of Geometry: As per simple principles of geometry, in an isosceles triangle, the line which divides the angle between equal sides equally, is perpendicular on the third side as shown in figure ( 7 - b ).
3. Combining 1 and 2 Above:
[0043] The combination of these two principles by which is devised a formula for reflection of ray of light whose direction is known and the direction of the target is also known as described below.
[0044] Shown in figure ( 7 - c ), is an isosceles triangle ABC where sides AB and AC are equal. If a ray of light CA is to be reflected in the direction AB then the mirror MR will have to be placed such that a perpendicular on the mirror at point A divides angle BAC in to two equal parts—as per the laws of reflection quoted above. In this position all the rays coming parallel to CA will be reflected in the direction parallel to AB. Now if the position of the mirror is shifted to the position of BC, even then all the rays parallel to the line CA will be reflected in the direction parallel to AB. This will happen so because AD is perpendicular on BC also because ABC is an isosceles triangle, and therefore line MR and BC are parallel to each other. So is achieved the formula that if the rays are coming in the direction parallel to one of the equal sides of an isosceles triangle and they are to be reflected towards the direction parallel to the other equal side of the triangle then the mirror has to be placed along the line parallel to the third side of the triangle, or the mirror may even be kept along the third line itself.
[0045] Now, coming to the application of the above formula what is to be achieved is that, the light coming from the Sun, which is changing its position every moment of the day, is to be reflected. Therefore, the point C will go on shifting its position because AC will always be sun-oriented, whereas the line BA will always be fixed as a fixed target to reflect light upon. When CA will be shifted, C will occupy some other position, say E 7 in the space, which will not be coplanar with our triangle ABC as shown in figure ( 7 - d );
[0000] therefore to be sure that our system continues to work, it must be ensured that the mirror is brought along the line BE so that all the three lines continue to be coplanar. It is also to be ensured that the new triangle ABE continues to be isosceles and the rays coming from the Sun are reflected along the direction parallel to AB—our target.
[0046] Therefore the following arrangement must be created where:
[0000] 1) Line AB is fixed,
2) Lines CA and AB maintain their original length, and still they are moveable on points A and B respectively so that ever changing position of the Sun (C)—and thereby ever changing direction of CA can be kept pace with. Also it is ensured that CA be always kept coplanar with the line AB.
3) The isosceles character of the triangle ABC is maintained—by keeping the length of CA and AB same, while the length of the line BC goes on changing due to change in the angle BAC as shown in figure ( 7 - d ). (This change in the angle between the Sun and the target can be seen in the FIG. 5 )
Application of Mechanics and Making of the Invention Machine.
[0047] (This is only an explanation how the above technique has been applied, the actual design is narrated later.)
[0048] Now to realize what has been narrated just above in paragraphs 1, 2 and 3 three bars occupy the positions of the three sides of our triangle ABC. For convenience the name of the components are designed on the basis of above principles.
Nomenclature:
[0049] Please see figure ( 8 ):
1 ) Sun-tracking bar will occupy the position of the line CA and may be named as SUN-ARM,
2 ) Bar holding the mirror will occupy the position along the line BC and may be named as MIRROR-ARM,
3 ) At the point B, mirror will have its pivot and may be named as MIRROR-PIVOT,
4 ) Sun-tracking bar—SUN-ARM—will rotate on point A as its pivot, therefore let us name this point A as SUN-ARM-PIVOT.
5 ) Bar occupying the position of the line AB will be oriented towards target and may be called TARGET-ARM.
Application:—
[0050] Now following arrangements are to be made as shown in FIGS. 8 and 9 :
[0000] 1 . Since the Sun will go on moving and the position of C will go on changing and therefore the magnitude of the angle BAC will also change during the day, therefore the Mirror-arm must be sufficiently long to allow all possible locations to point C after knowing the longest angle which the sun-arm may bear with the target-arm. Also the mirror-arm must have sliding-space on which the sun-arm will slide for different locations of C. 2 . Target-arm must be oriented towards the target and then must be fixed securely on a base to ensure that movements of sun-arm and mirror-arm do not disturb its fixed position. The target-arm must also have on one end of it a pivot for the mirror-arm, and arrangement to allow the movement of mirror-arm both ways—one in the circular direction along the circumference of the target arm and the other in the plane of sun-arm and target arm because the Sun will move not only east-west but also north-south-north; this north-south-north movement will appear in the form of up and down movement of the Sun. For this reason the target-arm must also have on the other end a pivot for the movement of sun-arm both ways to adjust for all positions of the Sun during the day.
3 . The sun-arm must have some arrangement so that while it slides on the mirror-arm, yet it keeps the mirror-arm moving so that the isosceles triangle of the three arms continues to exist.
[0051] If the above arrangements are made our system is complete for reflection of light on target area as shown in FIG. 8 .
[0052] However, if the size of the mirror is equal to only BC, then reflected light will keep changing the position and the target will not be fully illuminated at any point of time. Therefore, there must be an extention of the size of the mirror from B to F position as shown in FIG. 9 .
[0000] (Also the size and shape of illuminated area will go on changing and therefore size and the shape of the mirror should be such that the whole target area is always illuminated. An elliptic shaped mirror would be preferable, as it would illuminate nearly a circular area throughout.) Part-2: Sun-tracking system.
[0053] As narrated above in the description of the Redirection System would require a SUN-ARM—a bar—which should be sun-oriented throughout the day. This is realized in the present invention through a perfect tracking system, which provides solution for all the problems unsolved so far, through invention of new devices of declination-setter and time-setter as described herein below.
[0054] The present sun-tracking system is based on polar-axis tracking. Polar-axis tracking is based on the principle derived from following phenomenon:—
[0055] The earth moves around the Sun with a tilted axis and completes one round in a year. Because of the revolution of the earth around the Sun, position of the earth-axis in relation to the direction of the Sun undergoes change everyday which results in the change of declination of the sun at local noon as shown in FIG. 4 .
[0056] Now let us imagine that a bar is placed parallel to the axis of the earth—let us name this as polar-axis-bar and it is rotated such that its direction and speed neutralize the rotation of the earth. Then, if a second bar is fitted on this bar, and then this second bar is once oriented towards the Sun, this second bar will remain sun-oriented throughout the day because the said movement of the polar-axis-bar neutralizes the movement of the earth by moving from east to west (while the earth rotates on its axis from west to east). On the basis of this principle polar-axis tracking is done.
[0057] However, the next day, the second bar, let us name this as director-bar, will have to be moved north or south depending upon quantum of the shift of the sun. This is not a simple task The declination of the sun is uneven during the year. The difference is very vast which can be seen as follows:—
[0000] Period. Declination-Change (Northwards)
March 22 to April 22-12 degrees April 22 to May 22-8 degrees May 22 to June 22 3 degrees
[0058] Since this uneven change in declination has evaded any mathematical formulae, the problem has also evaded mechanical solution. Therefore, the scientists have opted sensor/computers etc for the purpose. The present inventor has solved this problem through his invention of declination-setter described later herein.
[0000] (For changing the position of the director-bar the inventor in his earlier invention—application 559/mum/2002 dtd.26 June 2002—solved this problem by using a calendar-arc on which there was marking for fixing the director-bar. The director-bar could be fixed for the date of operation manually, or through an electronically programmed motor. The calendar-arc was devised because the declination of the Sun changes unevenly as described below, and evades any mathematical solution which could be translated into a mechanical device.)
[0059] There is another problem in tracking the Sun. The movement of the sun cannot be synchronized with our earth-clock even when polar-axis sun-tracking is opted. This is so because the length of the day i.e. time elapsing between two local noons is not always 24 hours. The variation can be as much as nearly one minute. The cumulative effect of this variation over a period of time is too much; the earliest local noon at any place comes at 11-44 a.m. and the latest at 12-14 p.m.—a difference of half-an hour. This phenomenon is known as analemma-curve effect. This variation also being uneven during the year, also evades any mechanical solution. This problem has been solved through time-setter in the present invention. Inventor has invented these new components which ensure working of the machine automatically through-out the year and there is no need of adjusting the director bar for each day. The innovation is useful for all sun-tracking systems based on polar-axis tracking. These devices are described as below.
Declination Setter:
[0060] The device to set declination has been named as declination-setter. The mechanism is devised on the basis of following facts and imaginations:—
(Please see FIG. 3)
[0061] As narrated above the earth moves around the Sun with a tilted axis at 23.5 degree, and completes one round in 365.25 days.
[0062] Let us imagine that the position of the Sun and the earth are interchanged. By interchanging the position of the sun and the earth—the earth static and the Sun revolving around her—it will be found that different angles of sunrays are created on the earth-axis during the revolution of the Sun around the earth.
[0063] Let us further imagine, as shown in the third drawing of the FIG. 3 , that the Sun is stopped at a point and then the earth-axis is rotated around a perpendicular on the ecliptic—an imaginary plain in which the earth revolves around the sun during the year—then, all those angles will be created between the sunray and the earth-axis which are created by the (imaginary) revolution of the Sun around the earth. In this rotation of the earth axis it can be seen that a cone of 23.5 degree will be created by this rotation.
[0064] Now if the positions of the earth-axis and sunrays are interchanged i.e. instead of rotating the earth-axis against a fixed sunray, the sunray is rotated on the fixed earth-axis such that the sunray creates a cone of 23.5 degree as achieved by the rotation described above, one gets all the angles which were created by the above rotation of the earth-axis against the fixed Sun.
[0065] From the above is achieved a formula that if on the polar-axis-bar the director-bar is rotated such that it forms a cone of 23.5 degree, then it can cover all the positions of the sun during the year.
[0066] However there is again a problem. The Sun moves from north to south from 22 nd June to 22 nd December and from south to north from 22 nd December to 22 nd June, thus taking equal time, but it takes different time for moving from central position to 23.5 degree north and coming back to central position and then moving to south and coming back to central position; it takes roughly 186 days for the first and only 179 days for the second movement. This fact has also been taken into account while devising the declination setter.
[0067] The above formulae of 23.5 degree cone has been translated into mechanism as follows:—
(Please See FIG. 2 if Necessary.)
[0068] The purpose of declination-setter is to move the director-bar according to the change in the declination of the Sun; this can be done by moving director-bar on the polar-axis-bar to form a cone of 23.5 degree with its vertex on the axis of the polar-axis-bar as seen above. But the inventor has devised another device, the time-setter by providing for the polar-axis-bar a zero position as the staring point permanently, therefore the east-west movement of the director-bar in its conic movement would disturb the arrangement. Thus the requirement of the other device namely time-setter is such that the movement of the director-bar takes place in just two dimensional plane. Therefore more components have been added so that only north-south-north changes are obtained and the east-west changes of the director-bar caused by its conic movement are eliminated. This is achieved as follows. The polar-axis-bar is cut into two equal pieces and then a frame is fitted between the two pieces at a perpendicular. A bar, fitted in the frame, is placed along the perpendicular on the axis of the polar-axis-bar such that the axis of this another bar forms a right angle on the axis of the polar-axis-bar. Let us name this another bar as declination-bar. The declination-bar has free movement along its axis. There is a hole at the center of the declination-bar. A U-shaped clamp is fitted on a nail passing through the hole on this declination-bar. A thin bar is fitted on the clamp. Now if the thin bar is rotated in a circle, because of the combined effect of the nail and the clamp the declination-bar will also rotate. If the thin bar is rotated such that it forms a cone of 23.5 degree with its vertex on the axis of the declination-bar, the declination-bar will experience all the angles which a the director-bar needs in the north-south-north direction during the year. For achieving this the following arrangement is had.
[0069] On the frame on which declination-bar is fitted, there is another strip, let us call it second strip, parallel to the declination-bar. At the center of this second strip there is a pivot for a circular strip. This circular strip is an arc cut out of an imaginary circle which has its center on the axis of declination-bar, the thin bar is fastened on a hole on the circular-strip at a distance equal to 23.5 degree from its pivot. This circular-strip is rotated one full circle in one year. In its regular movement it causes all angles in the declination-bar for the year.
[0070] However, one has to provide for the eccentricity of the earth-orbit around the Sun which is experienced in the peculiarity that the central position for the sun on the polar axis comes once in 179 days and then in 186 days approximately. This is provided for as follows.
[0071] The circular-strip is fitted on an axle passing through the second-strip. On the other end of the axle is fitted another strip. This strip has a hole on which a nail coming from the parallelly moving gear disc is fastened.
[0072] There is a third strip on the frame, which is also parallel to the declination-bar. On this third strip a disc having teeth on its circumference is fitted parallel to the declination-bar. Though the gear is placed parallel to the declination-bar its pivot is eccentric in relation to pivot of circular-strip. A nail is fitted on this disc which is fastened on the strip fitted on the other side of the circular-strip. The distance of the nail from the pivot of the disc is scaled according to the difference—the quantum of eccentricity—between the pivots of the circular-strip and the disc and it has to be such that when the disc moves, the movement of the director-bar from central position to the south and back is completed by 177.2 degree movement of the disc and the northern movement of the director-bar is completed in 182.8 degree movement of the disc.
[0073] The disc completes one round in one year i.e. 365.25 days when moved by the timer. For convenience for installation or on resumption of operation after repair caused by breakdown etc., a circular lamina having marking of dates on its circumference may be fitted on the disc and may be named as calendar-disc. (This calendar may be used with caution keeping in mind the effect of leap-year.)
[0074] This declination setter is one complete invention in itself, yet it forms unity of invention of the present machine because it helps in automation of the polar-axis tracking system.
Time-Setter:
[0075] The device of time-setter is based on the actual experience of the difference in the timing of noon.
[0076] The device has two versions.
[0077] The first is based on the principle that there should be a fixed zero position for starting of the operation of the machine and it should reach the noon—the meridian position of the Sun—when the Sun is expected to be there as per real experience for the particular day and for the particular place where it is operating. The zero point will be resting point for the machine till it begins operating in the morning. On the basis of actual experience a the data is created for each place of operation and then a microprocessor is designed and programmed for starting of the machine at the time stipulated for each day of the year. This is a simple mechanism.
[0078] In the second version, the time bf starting the machine is fixed and no data or microprocessor is required; therefore this is preferable for reducing cost and easier maintenance of the machine. In this version the starting point is manipulated everyday.
[0079] For example if the machine is fixed for starting at 6 a.m. then for a standard day i.e. when the Sun actually reaches meridian point at 12.00 p.m. the polar-axis-bar will move 90 degree because it is moving at a speed of one round per 24 hours. So the basic point for starting will be 90 degree before the meridian point. A time-bar parallel to the director-bar is fitted on the polar-axis-bar and the basic point is decided as described above. Then with the help of time-disc described in the description of FIG. 6 which has varying radius for each day the time-bar is brought to the suitable starting point as per actual experience. This time-disc is not place specific because the apparent slow and fast movement of the Sun is same globally.
[0000] Combining of the Two Parts Viz. Redirection System and Sun-Tracking System:
[0080] As mentioned earlier the sun-tracking part is designed to realize the technique of the redirection system. In actual designing of the machine one has to just place the director-bar—described in Sun-tracking Part—in the sun-arm position of the system described above in Redirection System.
[0081] As shown in FIG. 1 in the actual design of the machine, however, while the same principle is used, the target-arm is truncated and only tiny axle ( 5 -A) as shown in FIG. 1 is retained. Also the sun-arm, though occupying the position as per original plan, is fitted on the polar-axis-bar and gets movement due to the movement of the polar-axis-bar.
[0082] By combining these two parts a complete machine has been created which has been described in the description of FIG. 1 .
[0000] Functions of the Components and their Assembling for Operation:—
(Please See FIG. 1.)
[0083] The whole device is supported by stand ( 1 ). The stand ( 1 ) has to be adjusted such that the shaft ( 7 -A) supporting arc ( 7 ) is in vertical position.
[0084] Arc ( 7 ) is then placed on the supporting shaft ( 7 -A) such that the polar-axis-bar ( 9 ) comes in the position parallel to the axis of the earth. Circular shape of Arc ( 7 ) ensures that in any position of the rotating bar ( 9 ) the pivot point of director bar is at the same distance from mirror-pivot.
[0085] The mirror is fitted on the mirror-arm ( 12 ) such that its surface is precisely parallel to the axle ( 4 ). Free movement of axle ( 4 ) and ( 5 -A) must be checked before slide ( 11 ) is fitted into mirror-arm ( 12 ) and the machine is put to operation.
[0086] With the help of declination-setter ( 8 ) the director-bar ( 10 ) is set at the position for the date of operation. In this position the director bar has the same angle with the polar-axis-bar ( 9 ) as the sun has with the earth-axis on that day of the year.
[0087] The time-setter is also adjusted for the date of operation so that the machine starts at the desired time next day. Timer of the Time-setter is also put on. Before starting timer ( 13 ) the director-bar which has extension on the other side of the mirror arm ( 12 ) bar disc ( 14 ) is fitted and the rotating bar is rotated on either side until there is no shadow of the bar on the disc. This ensures sun-orientation of the director-bar ( 10 ).
[0088] Then Arc-couple ( 3 ) and ( 6 ) are so adjusted that the sun-light is reflected on the desired target area. The sun orientation of the director bar ( 10 ) must be checked again and arc couples and director bar adjusted if necessary.
[0089] Now the timer ( 13 ), timer of the declination setter and the timer of the time-setter must be put on.
Working of the Machine:—
[0090] When timer ( 13 ) is energized by the spring work/electricity starts moving the polar-axis-bar ( 9 ), the director bar ( 10 ) also starts moving. This movement of the director bar ( 10 ) ensures that it is constantly sun oriented. By the movement of director bar, the slide ( 11 ) fitted on the director bar ( 10 ) starts moving the mirror arm. The mirror-arm has movement in two directions and as explained earlier, it continues to occupy the position of the third side of the triangle which ensures reflection of sun light parallel to the direction of target arm. As long as the timer ( 13 ) keeps moving the rotating bar at the speed of one round every 24 hours, sun-light is reflected continuously on the target area until the sun sets in the west. | An automatic sunlight redirector comprises of a device which redirects sunlight to a place of user's choice. This is a universal model and does not need data and microprocessor to track the sun at different latitudes, nor does it need any computer to calculate the angle of reflectance. This device works on principle of arranging incident sun-ray, target-line and the mirror-axis as sides of an isosceles triangle and is realized by the devices of sun-tracking director-bar, a slide fitted on this director-bar, and a groove on the mirror-axis pipe/bar ( 5 ) for free movement of the director-bar ( 10 ) which not only tracks the sun but continuously adjusts the position of the mirror such that the light is reflected on the fixed target. The declination-setter ( 8 ) and time-setter ( 15 ) track the daily changes in the declination of the sun and the length of the day respectively. | 5 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of earlier application Ser. No. 454,623, filed Dec. 21, 1989, now abandoned which, in turn, is a continuation-in-part of application Ser. No. 280,481 filed Nov. 18, 1988, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to fluorescent marking compounds and more particularly to fluorescent marking compounds which transfer to anything coming in contact with a treated surface.
2. Related Prior Art
Fluorescent compounds and marking solutions are well known in the art. Numerous powders, liquids and pastes are commercially available. Many of these products are used to impart "invisible" marks for purposes of theft detection, inventory control, quality control, tracking, document security and verification, and the like. Preferred products feature a low color profile in while light and a strong fluorescent signal under long, short or midwave ultraviolet light.
In the field of theft detection, to which the instant invention most particularly pertains, it is highly desirable to have an easily applied product which will impart both a long term, rub-out resistant, "blow-away" proof, strong fluorescent mark to the material being treated and still be capable of readily transferring to the hands of a thief upon only minimal contact and in a quantity sufficient to ensure that the fluorescent residue is easily detectable on the thief's fingers when examined under low-powered UV light. Such a fluorescent compound is ideally noncolor-contributing under white light examination and must not impart undesirable or unusual textural properties, such as a stiff, gritty or greasy feel.
While dry organic and inorganic fluorescent powders can be applied by brushing, rubbing or otherwise distributing them over the paper's surface so to minimize any sign of treatment under white light examination, these techniques are time consuming, messy and uneconomical, and are incapable of efficiently and uniformly marking every square millimeter of a dollar bill, for example. As a practical matter, it is unrealistic for investigators to treat large amounts of currency, such as might be involved in a ransom operation, in such a manner. Furthermore, these application methods typically leave a gritty feel because conventional grinding and milling techniques are generally capable of economically providing powders having diameters in the submicron range. In those cases when finelydivided organic powders are available, normal storage results in undesirable clumping and aggregation. The most critical shortcoming of this approach, however, is the nonpermanent nature of the markings: they may be rubbed off or blown away by bursts of compressed gas, as virtually none of the fluorescent organic compound penetrates the fibrous web.
Another marking approach involves dissolving an organic fluorescent compound in a solvent and spraying or otherwise applying the solution to currency or other porous materials. Among the critical shortcomings of this technique is that most solvents carry the fluorescent compound into the web and little, if any, powder is available on the surface for ready transfer to a thief's fingers, pockets, wallet, or other surfaces. Thus it will be seen that merely dissolving an organic fluorescent compound in an organic solvent does not provide a product having optimum, or even satisfactory, transfer capabilities. This limitation can be overcome by utilizing solvents characterized by a narrowly defined boiling point range in combination with dissolved fluorescent agents at specified concentrations, as described herein.
Another approach involves dispersing an inorganic phosphor or organic fluorescent compound in a solvent and spraying or otherwise applying the mixture to currency or other surfaces. In such a system the fluorescent phosphor or compound is insoluble or very substantially insoluble in the solvent. An example of such an approach would be a mixture of an inorganic zinc sulfide-based fluorescent phospor in 1,1,1-Trichloroethane or methyl ethyl ketone, two common volatile solvents. A serious shortcoming of this approach is that most of the fluorescent compound is deposited on the surface of the currency, where it is easily blown or wiped away. Additionally, the application is usually uneven, often gritty, and is almost always noticeable to a thief. Further disadvantages of this approach include the easy visibility without a UV light of the fluorescent compound, and the limitation of having to treat each bill or surface individually, as it is extremely difficult to maintain particles in uniform suspension without the use of various nonvolatile processing aids. Thus it will be seen that merely dispersing an organic or inorganic fluorescent compound in a solvent will not cause the treated surface to be permanently marked, because the fluorescent powder, which is insoluble in the solvent, cannot adequately infiltrate the paper web.
The use of fluorescent solutions is described in the patent literature. U.S. Pat. No. 3,812,052 to Weston and 3,960,755 to Beachem, et. al. describe compositions consisting of fluorescent compounds dissolved in solvents characterized by a diverse range of boiling points, including polar solvents such as water and butyl formate which would cause paper to swell. Each of these patents teaches the use of a resin or polymer dissolved in the solvent, rendering them unsuitable for the surreptitious marking of paper webs as taught in the instant invention. U.S. Pat. Nos. 3,753,647 and 3,899,450 to Molina teach a dye penetrant for detecting flaws and defects on nonporous metal surfaces comprising fluorescent dyes and volatile halocarbon solvents in combination with substantially higher-boiling ketone or alkyl pyrrolidone solvents and nonvolatile nonionic surfactants, which agents would stain paper and impart a greasy character. The use of novel fluorescent compounds in various coating and printing vehicles is described in U.S. Pat. Nos. 3,169,129 to Rodgers, et. al. and 3,066,105 to McCafferty.
SUMMARY OF THE INVENTION
Surprisingly, it has been found that a solution containing between 0.05-2.5 (g of fluorescent compound in 100 ml of solvent), and most preferably about 0.05-1.4 of selected fluorescent dissolved in volatile halocarbon solvents is capable of both marking the paper or other fibrous web in a substantially permanent fashion which resists attempts to remove the powder by rubbing or applying a stream of compressed gas, yet provides for excellent transfer of the fluorescent compound in response to the lightest touch. The system can be quickly and easily applied to hundreds of bills in minutes by pouring or immersion. Advantageously, no grit or unusual feel is imparted to treated materials. Of critical importance, treatment of most papers can be quickly accomplished by an unskilled operator so that the marking is undetectable in white light to the unaided eyes, yet provides a very strong fluorescent signal under long, short or midwave UV light, including the lowest powered hand-held commercial models. An additional advantage is the low order of toxicity of the preferred fluorescent compounds relative to most inorganic phosphors and 8-Hydroxyquinoline chelates used in commerce. A further advantage is the excellent adhesion to skin and other surfaces as compared to inorganic phosphors and many other organic fluorescent compounds. A still further advantage of the present teachings is that a simple fluorometric field assay is available since the fluorescent emission wavelength shifts toward the blue on the application of organic or inorganic bases. Additional advantages include the speed, convenience, and uniformity of each application. The present system affords other advantages which will be apparent to those skilled in the art upon a reading of the specification and the appended claims.
DESCRIPTION OF THE PREFERRED EMBODIMENT
"Organic fluorescent compound" and "fluorescent organic compound" includes organic compounds which emit visible radiation in the spectral region of about 380-700 nanometers when irradiated by commercially available ultraviolet lights. By ultraviolet light is meant radiation between about 250-370 nanometers. Since it is an important object of the instant invention to provide a product which, on application to paper and other porous webs and surfaces, is essentially invisible to the unaided eye without UV illumination, the preferred organic fluorescent compounds will be white, off-white, colorless or nearly colorless, or otherwise essentially noncolor contributing in the dry state; however, colored fluorescent compounds are also suitable for specific applications, particularly when matched with the color of the surface to be treated.
The preferred compounds are fluorescent azoles. These include heterocycles containing nitrogen substitution, and are particularly intended to include benzoxazoles (containing nitrogen and oxygen substitution) and benzothiazoles (containing nitrogen and sulfur substitution), and their derivatives. Selected members of these classes of compounds are described, for example, in paper by David L. Williams and Adam Heller starting on page 4474 of the Journal of Physical Chemistry, Vol. 74, No. 26, 1970. Of particular interest are the compounds appearing in Table I of the cited Williams and Heller paper which have quantum efficiencies greater than 13.0. The preferred compound of this class is 2-(o-Hydroxyphenyl)benzothiazole. After several washings with ethanol and recrystallization from acetic acid, the product of commerce appears as a nearly-white crystalline powder which is characterized by a strong green fluorescent signal under UV light.
Other compounds which are suitable as the fluorescent compounds of this invention include the 2-ortho-hydroxyphenyl4-(3H)-quinazolinones as described in U.S. Pat. No. 3,169,129 to Rodgers and Millionis. Of particular interest are the following disclosed compounds:
2-(2-hydroxypheny)-4(3)-quinazolone;
2-(2-hydroxy-4-methoxyphenyl)-4(3)-quinazolone;
2-(3,5-dichloro-2-hydroxyphenyl)-4(3)quinazolone;
2-(5-chloro-2-hydroxyphenyl)-4(3)-quinazolone;
2-(2-hydroxy-3-methylphenyl)-4(3)-quinazolone;
2-(4-ethyl-2-hydroxyphenyl)-4(3)-quinazolone
Still other compounds suitable as the organic fluorescent compounds of this invention are described in U.S. Pat. No. 3,066,105 to McCafferty. Of particular interest are the fluorescent derivatives of 2-(o-Hydroxyphenyl)benzothiazole and 2-(o-Hydroxyphenyl)benzoxazole described in columns 3 and 4 of said patent.
Still additional compounds of interest include the coumarin derivatives which are used as laser dyes. These compounds are described in Eastman Kodak Laboratory and Research Products Catalog No. 53 on pages 106-111. Among these "laser dyes" are Coumarin 1, 2, 4, 6, 7, 30, 102, 120, 138, 151, 152, 153, 307, 314, 334, 337, 338, 339, and 343. The fluorinated coumarin derivatives, such as Coumarin 153 and 152, while color-contributing, have high quantum efficiencies and are easily soluble in halocarbon solvents.
Although not as satisfactory for identification purposes as other recited organic fluorescent compounds due to the ubiquity of blue-fluorescing compounds, the blue fluorescing solvent-soluble optical brighteners are suitable for the current invention. These include proprietary commercial products such as Uvitex® OB, a bis(benzoxazolyl) derivative; PHORWITE® BBH, a stilbene derivative; PHORWITE® K2002, a pyrazoline derivative; and although characterized by very low solubility in nonpolar solvents, LEUCOPURE®EGM.
Another class of fluorescent compounds, although often colored under white light examination, includes conjugated polycyclic aromatic compounds which have at least 3 fused rings. These include, without limitation, anthracene, benzanthracene, phenanthrene, substituted phenanthrene, napthacene, pentacene, substituted pentacene, and derivatives thereof.
Other fluorescent compounds also may be used provided that they are soluble at room temperature in the organic solvents of the invention at concentrations of at least about 0.01% and more preferably about 0.05% on a weight/volume basis. The preferred fluorescent compounds are solids in the dry state so that as the solvents evaporate during the treatment process, the fluorescent compound will precipitate out of solution and deposit as an extremely fine powder on contact with the paper or other surface. In this way, the very finely precipitated powder is available on the surface of treated materials for ready transfer to fingertips and other surfaces. The preferred treatment processes or application methods include pouring the fluorescent marking solution over paper or fabric, dipping items to be marked into the marking solution, application by pipette or premeasured dosage syringes, by brush or fabric dauber and, less desirably, by aerosol sprayer. Additionally, the most desirable compound have a high quantum efficiency, a low order of toxicity, are nonreactive with the preferred solvents, are noncolor contributing, and have good substantivity to skin and other surfaces. Organic fluorescent compounds which are insoluble or substantially insoluble in water are advantageous in that they cannot be easily washed off once applied to a surface. Other features of the preferred organic fluorescent compounds include good lightfastness, heat stability, and fluorescent colors which are distinctly different than those found in common items of commerce (i.e. fluorescent colors other than blue). Selected fluorescent compounds may be mixed and the fluorescent solution may contain a combination of fluorescent compounds. Although most of the fluorescent compounds recited herein exhibit visible fluorescence when irradiate by long or shortwave UV light, it is within the scope of this invention to utilize fluorescent compounds which exhibit visible fluorescence only under shortwave UV or only under longwave UV or, alternately, exhibit a first color under longwave UV and a second color under shortwave UV.
In selected cases, it may be desirable to utilize as the fluorescent organic compounds of this invention, those which sublime at or slightly above room temperature. In this way tell-tale fluorescent residues will be deposited on surfaces (such as the interior of a wallet or envelope) contiguous to, or in close proximity to, the treated documents, fabrics, or other marked material. 2-(o-Hydroxyphenyl)benzothiazole and 2-(o-Hydroxy-5-methoxyphenyl)benzothiazole, along with other low molecular weight azoles, have been observed to sublime when subjected to elevated temperatures such as those expected in an automobile glove compartment during summer months.
It is also within the scope of this invention to add to the solvents, along with the fluorescent organic compound or combination of compounds, substances such as colorimetric reagents, organometallic compounds, oils and other substances which impart a characteristic taste, odor, or "vapor trail" or "signature" colored dyes, and the like. These substances also may be dissolved in the solvents of the invention without any organic fluorescent compounds, in which case marked currency and the like would not necessarily exhibit any visible fluorescence under UV light. Such compounds may also be added in addition to the fluorescent compounds of the instant invention for purposes of adding unique chemical "tags."
The preferred solvents in accordance with the teachings of this invention include those which have a boiling point or distillation range at 760mm Hg between about 12°-35° Centigrade, and most preferably between about 19°-28 C. Solvents which have boiling points or distillation ranges above about 35° C. tend to carry virtually all of the fluorescent compounds into the fibrous web or fabric fibers, leaving a negligible quantity on the surface for transfer to a thief's hands. The effect is particularly dramatic when applied under cool ambient air conditions, i.e., lower than about 65 degrees Fahrenheit. Solvents with boiling points or distillation ranges below about 15° C. tend to evaporate before even contacting the paper, resulting in marginal penetration, thereby limiting the permanent marking ability of the solution. Additionally, solvents boiling at such low temperature are generally impractical to work with, present packaging and shipping limitations, and pose a frostbite threat to unprotected skin. Nevertheless, solvents with boiling points as low as about 12 degrees C. can be useful for special cold weather applications.
So as not to damage paper sheets, the preferred solvents should be nonpolar liquids, although in limited situations such as the treatment of colorfast fabrics, moderately polar solvents, preferably used in combination with nonpolar liquids, may be considered. Highly polar and hydrogen bonded solvents are generally unsatisfactory for most purposes of this invention since their polar character as indicated by relatively high solubility parameter values will tend to swell paper fibers, thereby causing visible damage, thus minimizing the utility of the instant invention for use on paper. Further, polar and even moderately polar compounds are not preferred due to their strong tendency to cause most inks to run. A full discussion of solubility parameters, including nonpolar, moderately polar, and polar liquids is found in the CRC Handbook of Solubility Parameters and other Cohesion Parameters, 1983, by A. Barton.
Among the preferred solvents are the halocarbons, particularly chlorofluorocarbons and hydrochlorofluorocarbons. These solvents typically have low toxicity profiles, very low surface tension values, low solubility parameter values, relatively low solvent power values (i.e., low Kauri-Butanol values), pose little or no fire risk and tend to be volatile below their literature boiling points. One chlorofluorocarbon which is particularly advantageous in the practice of the instant invention is Fluorotrichloromethane, which is sold under the tradenames FREON® 11 AND GENETRON® 11. This solvent has been extensively studied and is characterized by a low order of toxicity and is nonreactive with the organic fluorescent compounds of this invention. Substitutes for this compound which are believed to have less tendency to degrade the earth's protective ozone layer include fluorocarbons 123(CH2FCF3) and 141b(CH3CCL2F) and other developmental products, as described, for example, in Chemical & Engineering News, Vol. 66(1988), No. 6, pp 17-20, which is incorporated herein by reference.
Additional volatile organic solvents which are useful in accordance with the practice of this invention, alone or in combination with other solvents to achieve the necessary degree of solvency to dissolve desired amounts of organic fluorescent compounds, include without limitation:
______________________________________1,2-Dichloro-1,2-difluoroethylene BP @ 760 mm Hg 21-22° C.1,1-Dichloro-1,1-difluoroethylene 191,2-Dichlorotrifluoroethane 283,3,4,4,5,5,5-Heptafluoropentene-1 302,2,2-Trifluoroethyl bromide 262,2-Dichloro-1,1,1-trifluoroethane 271-Chloro-1,1,3,3,3-pentafluoropro- 28paneOctafluorocyclopentene 272-Bromo-1,1,1-trifluoroethane 26Dibromodifluoromethane 25______________________________________
Those compounds mentioned above which have unsaturated bonds pose potential health threats and must be applied using appropriate protective measures. In addition to the use of halocarbons may be mentioned the use of suitable hydrocarbons, such as 2-Methylbutane, 1-Pentene and volatile silicon-containing liquids characterized by boiling points within the teachings of the instant invention. Despite their limitations for general applications, which are noted in parentheses, 1,1,1-Trifluoroacetone (high toxicity, high solvent power), ethyl chloride (extremely flammable, frostbite risk) and methyl formate (relatively high polarity) may also be mentioned as being useful for special applications or may be used in minor proportions in combination with other preferred solvents of the instant invention.
The concentration of dissolved fluorescent organic compound in the volatile solvents of this invention should be sufficient to impart a readily detectable fluorescent mark under UV light on the material being treated and allow for ready transfer to a thief's fingers upon contact, and most desirably upon light contact. The exact concentration is dependent upon a number of factors, including the fluorescent intensity of the fluorescent organic compound, the characteristics (such as fluorescence, texture, porosity, color) of the surface being treated, the desired degree of transfer, limitations imposed by the maximum quantity of a fluorescent compound or combination of fluorescent compounds which will dissolve in a given quantity of volatile solvent or a mixture of volatile solvents (including an azeotropic or nonazeotropic mixture of an active solvent capable of dissolving the fluorescent compound and a nonsolvent diluent, which may be a perfluorinated liquid having a boiling point within the range of the instant invention), and the white-light color of the fluorescent organic compound. A range of between about 0.01% w/v to the saturation point may be mentioned. As a general rule, the closer to the saturation point, the greater the quantity of fluorescent compound that will precipitate on the surface of the item being treated. In some cases, such as manila envelopes which do not contain appreciable amounts of fluorescent brighteners and have essentially no observable fluorescence under UV light, very low concentrations of the selected fluorescent compound or combination of compounds will impart a satisfactory signal and suitable transfer. On the other hand, papers and fabrics which contain brighteners or fluorescent dyes will require higher levels of fluorescent compounds for a readily detectable signal to be observed under UV light. In some circumstances the concentration of fluorescent compound can be reduced so that there is virtually no transfer of fluorescent compound to fingertips and other surfaces.
It is also within the scope of this invention to utilize supersaturated solutions of fluorescent organic compounds and to incorporate minor percentages of solvents which have boiling points or distillation ranges which slightly exceed 35° C., as cosolvents in order to dissolve selected fluorescent organic compounds.
Having provided a description of the invention, the following examples are given to more fully illustrate the teachings of the invention. The examples are not intended to limit the scope of the invention.
EXAMPLE 1
0.27 g of 2-(o-Hydroxyphenyl)benzothiazole was dissolved in 30 milliliters (approximately 0.68% weight/weight; 0.9% weight/volume) of Dichloromethane, a volatile organic solvent which has a literature boiling range at 760 mm Hg of between 39.8°-40.0°C. and is a solvent for the organic fluorescent compound. Approximately 3 milliliters was poured over a dollar bill from a height of 3 inches at room temperature. The solvent evaporated in approximately 45 seconds. No sign of treatment was apparent under white light; under long wave UV light, a strong fluorescent signal was observed. When two fingertips were lightly passed over treated portions of the bill and then examined under UV light, virtually no fluorescent powder was observed on the fingertips. This example serves to illustrate the critical limitations which result from the use of a solvent with a boiling range above the upper limits of this invention.
EXAMPLE 2
0.27 g of 2-(o-Hydroxyphenyl)benzothiazole was dissolved with stirring in 30 milliliters (approximately 0.6% weight/weight; 0.9% weight/volume) of Fluorotrichloromethane, a volatile organic solvent which has a literature boiling point of 23.7° C. and is a solvent for the organic fluorescent compound. Approximately 3 milliliters was poured over a dollar bill from a height of 3 inches at room temperature. In about 15 seconds the solvent evaporated. No sign of treatment was apparent under white light; under longwave UV light, a very strong fluorescent signal was observed. When two fingertips were lightly passed over treated portions of the bill and then examined under UV light, a very strong green fluorescent signal was observed under longwave UV light; under white light, there was no visible residue on the fingertips.
Further, the fingertips which contacted treated portions of the bill were in turn contacted with dark clothing, an amber bottle and a leather wallet. In all cases, the fluorescent powder was transferred to the objects. This example is illustrative of a preferred embodiment of the invention.
EXAMPLE 3
A 0.6% w/w solution (0.9% weight/volume) of 2-(o-Hydroxy-5-methoxyphenyl)benzothiazole was prepared in Fluorotrichloromethane. The fluorescent solution was applied as described in examples 1 and 2. Following evaporation of the solvent, a moderately strong orange signal was observed under longwave UV light on treated areas of the dollar bill. There was no sign of treatment on examination under white light. The powder readily transferred to fingertips on glancing contact where it was plainly visible under UV light, but not under white light. This example is illustrative of the use of a 2-(o-Hydroxyphenyl)benzothiazole derivative in the practice of the invention.
EXAMPLE 4
A 1.34 w/w (2.01 weight/volume) solution of 2-(o-Hydroxyphenyl)benzoxazole was prepared in Fluorotrichloromethane. The fluorescent solution was applied as described in examples 1 and 2. Following evaporation of the solvent, a strong blue-green fluorescent signal was observed under longwave UV light on treated areas of the dollar bill. There was no sign of treatment under white light. On light, glancing contact the powder readily transferred to fingertips and was plainly visible under longwave UV light, but not under white light. This example illustrates the use of a benzoxazole derivative in accordance with the teachings of the invention.
EXAMPLE 5
A 0.46% w/w (approx. 0.58% weight/volume) solution of 2-(o-Hydroxyphenyl)benzothiazole was prepared in the hydrochlorofluorocarbon 1,1-Dichloro-1-fluoroethane. The fluorescent solution was applied to currency as described in examples 1 and 2. In addition, the solution was poured over white bond paper (Southworth Stock no. 403C). Treated papers were fanned in the air for 10 seconds until dry. While no sign of treatment was evident on unaided examination, a strong green fluorescent signal was observed under both short and longwave UV light. Glancing contact resulted in very slight transfer of the fluorescent agent to fingertips; repeated handling resulted in good transfer to the fingertips. The transfer was undetectable without the use of UV light. This example serves to illustrate the use of a hydrochlorofluorocarbon in the practice of the invention and the use of a low concentration of fluorescent compound to limit transfer only upon repeated contact or aggressive frictional contact.
EXAMPLE 6
A 1.2% w/w (1.77% weight/volume) solution of 2-(o-Hydroxyphenyl)benzothiazole was prepared in the hydrochlorofluorocarbon 2,2-Dichloro-1,1,1-Trifluoroethane. The solution was applied to currency and bond paper as described in examples 1 and 2. In addition a dollar bill was immersed for five seconds in the solution, then allowed to air dry. In each case, no sign of treatment was evident to the unaided eye, while UV examination revealed a strong green fluorescent signal on treated portions. The fluorescent residue readily transferred to dry fingertips upon light handling where it was detectable under UV examination only. After repeated handling, the fluorescent powder continued to transfer without significantly diminishing the fluorescent intensity on the respective paper surfaces. This example serves to illustrate additional application techniques and the use of a hydrochlorofluorocarbon in the practice of the invention.
EXAMPLE 7
Using the hydrochlorofluorocarbon of example 6, a solution having a strength of 1.6% w/w (2.36% weight/volume) of 2-(o-Hydroxyphenyl)benzothiazole was prepared with vigorous stirring. A wool dauber was immersed in the solution and while still wet, was rubbed over the face of a dollar bill and bond paper. No damage to the respective papers was noted and the fluorescent residue transferred readily to fingertips in light frictional contact. The areas of the papers which were handled retained their intense fluorescent character. In a variant, the instant solution was poured over a KLEENEX tissue. The tissue was allowed to dry and return to room temperature whereupon it was used as a fluorescent "duster" to impart finely precipitated fluorescent powder to a wide variety of wiped surfaces, including papers, plastics, glass, metals, and fabrics. This example serves to further illustrate the use of a hydrochlorofluorocarbon.
EXAMPLE 8
A w/w solution of approximately 0.9% (approx. 0.58% weight/volume) of 2-(o-Hydroxyphenyl)benzothiazole in 1-Pentene was prepared. The solution was applied to currency as described in example 2, with very similar results. Since 1-Pentene is miscible in all proportions with most of the preferred fluorocarbons as described herein, suitable solutions may comprise a mixture of 1-Pentene and one or more of the recited fluorocarbons. This example illustrates the use of a hydrocarbon solvent in the practice of the instant invention. | A composition for rendering materials fluorescent substantially without visible trace comprises an organic fluorescent compound dissolved in a solvent characterized by a boiling point or distillation range at atmospheric pressure of between about 12°-35° C. The preferred composition comprises fluorescent azoles, such as 2-(o-Hydroxyphenyl)benzoxazole, 2-(o-Hydroxyphenyl)benoxazole, and derivatives thereof dissolved in volatile halocarbon solvents, such as Fluorotrichlormethane, 1,1-Dichloro-1-Fluoroethane, and 2,2-Dichloro-1,1,1-Trifluoroethane. The resultant product is particularly suited for marking currency, papers, fabrics, and other porous webs and surfaces. Treated surfaces appear normal in white light, are highly fluorescent under UV light and feature excellent transfer of the fluorescent compound to fingertips and other surfaces in direct or glancing contact. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a door handle system that employs a plurality of levers for simultaneously latching and unlatching a plurality of associated latch mechanisms provided on a door. This door handle system employs varying numbers and placement of levers and associated latch mechanisms, can be installed on doors that open to the inside or on doors that open to the outside, can be used on either left or right hand opening doors, can be operated from either side of the door, and can be locked by employing a single padlock in association with only one of the levers of the system.
2. Description of the Related Art
Most of the door handle systems that are currently employed utilize only one latch mechanism to hold the door shut. One latch mechanism holds the door to the door frame in only one location. For use with doors that are flexible and can be easily warped, such as metal doors, it is desirable to employ door handle systems with more than one latch mechanism so that various points on the door can be held to the door frame.
Various multiple latch door handle systems have been proposed. However, each of these multiple latch door handle systems has one or more problems associated with its installation or use.
Some of the multiple latch door handle systems have a number of latch mechanisms that work independently. These systems are time consuming to open and close because each latch mechanism must be operated individually in order to open or close the door.
Other multiple latch door handle systems employ latch mechanisms that work in conjunction with each other, but are designed so that the latch mechanisms must be located at a certain point and distance from the other latch mechanisms in the system. Installation of these systems can be time consuming, and often the locations of the latch mechanisms are not convenient for the door onto which they are to be installed.
Still other multiple latch door handle systems are complicated in operation and may employ latch mechanisms that are directed in opposite directions from each other. Again, installation for these types of systems is complicated and time consuming. The systems are not flexible enough for installation on different types or sizes of doors, on both left and right hand opening doors, or for inside and outside opening doors without making major modifications to the hardware. These systems often employ complicated linking mechanisms with numerous parts that can break. Once a part is broken on one of these systems, they are often hard to repair.
Some multiple latch door handle systems are designed for installation on only one side of a door, i.e. either a right handed opening door or a left handed opening door. And most of these multiple latch door handle systems can not be opened from both sides of the door, i.e. opened from both the front side and back side of the door and can not be used on both inside opening doors and on outside opening doors.
Also, many of these multiple latch door handle systems are difficult or impossible to lock so that all of the latch mechanisms of the system remain locked in a latched position.
The present invention addresses all of these problems by providing a simple, multiple latch door handle system for simultaneously latching and unlatching a plurality of associated latch mechanisms provided on a door. The present door handle system is easy to install, allows flexibility in the number of levers and latch mechanisms employed, and allows flexibility in the distance that the levers and latch mechanisms are spaced apart from each other. This system can be installed either an inside opening door or on an outside opening door, can be used on either a left hand opening door or a right hand opening door, and can be operated from either side of the door. Also, all of the latch mechanisms of this door handle system can be locked in a latched position by employing a single padlock in association with the distal end on just one of the levers of the system.
SUMMARY OF THE INVENTION
The present invention is a door handle system that employs a plurality of levers for simultaneously latching and unlatching a plurality of associated latch mechanisms provided on a door. This system is mounted externally on the door to the surface of the door and to the surface of the door frame so that the entire system is readily visible and accessible for operation and repair.
Each lever is paired with and attached to an associated latch mechanism so that the latch mechanism rotates in conjunction with its associated lever. Each lever is provided with a shaft that is provided on a proximal end of the lever. The shaft extends outward from the lever so that a longitudinal axis of the shaft is approximately perpendicular to a longitudinal axis of the lever. Two opposite sides of the shaft are flattened along the length of the shaft so that items that are fitted to the shaft, i.e. are provided with openings therein having two flattened sides to the opening, and are slipped over a distal end of the shaft will not be able to rotate relative to the shaft, but those items will rotate in conjunction with rotation of the shaft and its associated lever.
A groove is provided in the proximal end of the lever so that the groove surrounds the shaft. A compressible washer slips over the distal end of the shaft and is received in the groove to seal the lever to the door in order to prevent air leakage between the door and the lever.
Next, a hollow snap bushing is placed over the distal end of the shaft so that a cylindrical end of the snap bushing faces away from the lever. The opposite end of the snap bushing is provided with a shoulder which has a larger diameter than the diameter of the cylindrical end. Then the shaft is inserted through an opening provided in a door for this purpose, and the cylindrical end of the snap bushing enters the opening and is secured therein by wings that are provided on the cylindrical end, with the shoulder resting against the front surface of the door.
After the shaft has been inserted through the opening in the door, a hollow second bushing inserts over the distal end of the shaft so that a cylindrical portion of the second bushing extends through the opening in the door. The second bushing is provided with a shoulder that is larger in diameter than its cylindrical portion, and this shoulder engages the back surface of the door. The shoulder of the second bushing rests against the back surface of the door.
Next a collar with a shaft opening therein is slipped, via its shaft opening, over the distal end of the shaft and is secured to the shaft by a screw that inserts into a screw opening that is provided in the collar approximately perpendicular to the longitudinal axis of the shaft. A shaft opening in the collar is fitted to the shaft, i.e. it is provided with two flattened sides to the shaft opening. The collar is provided with a second groove similar to the groove provided in the proximal end of the lever. The second groove receives the shoulder of the second bushing. The screw is threaded into the screw opening until a tip of the screw engages the shaft, thereby securing the collar to the shaft and capturing the second bushing, door, snap bushing, and washer between the collar and the lever.
A latch mechanism with a shaft opening therein is next slipped onto the shaft, via its shaft opening, and is secured to the shaft by a second screw that inserts into a second screw opening provided in the latch mechanism approximately perpendicular to the longitudinal axis of the shaft. A shaft opening in the latch mechanism is also fitted to the shaft, i.e. it is provided with two flattened sides to the latch mechanism opening. The second screw is threaded into the second screw opening until a tip of the second screw engages the shaft, thereby securing the latch mechanism to the shaft.
The latch mechanism has a circular protrusion on a back or rear side of the latch mechanism by which the latch mechanism attaches to a bus bar. The circular protrusion is provided with a third screw opening that is provided approximately parallel with the longitudinal axis of the shaft but is offset therefrom because the circular protrusion is provided on a distal end of an arm that extends outward approximately perpendicular to the longitudinal axis of the shaft. The circular protrusion is first inserted through a protrusion opening provided in the bus bar for this purpose, and then a third screw is first inserted through a large diameter second washer and bar bushing and then threaded into the third screw opening to secure the latch mechanism to the bus bar. The bar bushing is provided with a cylindrical end that enters the protrusion opening and with a shoulder that abuts the bar.
When inserting the latch mechanism onto the shaft and before the latch mechanism is attached to the bus bar, either a front side of the latch mechanism can face the shaft when the latch mechanism is inserted onto the shaft, as illustrated in FIGS. 2, 3 and 3 A, or alternately, a rear side of the latch mechanism can face the shaft, as illustrated in FIG. 2A, when the latch mechanism is inserted onto the shaft. The circular protrusion is provided on the rear side of the latch mechanism and it attaches to the bus bar to operationally link this latch mechanism with other identical latch mechanisms to form the door handle system.
The shaft opening in the latch mechanism is provided with two flattened sides that can align with the two flattened sides of the shaft in two different ways simply by rotating the latch mechanism while keeping the front side of the latch mechanism facing the door. Therefore, when the latch mechanism is facing the door, it can be inserted on the shaft in one of two ways so that the latch mechanism can be employed to fit either right or left hand doors, i.e. it can be inserted directly so that the flattened sides of the latch mechanism coincide with the flattened sides of the shaft or it can be rotated 180 degrees before inserting it on the shaft. In addition, the latch mechanism can be flipped over 180 degrees so that the rear side of the latch mechanism faces the door, as previously described. In this orientation, i.e. with the rear side of the latch mechanism facing the door, the latch mechanism can also be inserted on the shaft in one of two ways, similar to the two different ways the latch mechanism could be inserted on the shaft when the front side of the latch mechanism faced the door.
The latch mechanism is provided with a wedge shaped tongue that extends outward perpendicular from the longitudinal axis of the shaft and is located in a plane that is parallel to a plane in which the arm is located. A longitudinal axis of the tongue forms an obtuse angle of approximately 140 degrees with a longitudinal axis of the arm, with a pointed edge of the wedge facing away from the arm.
A plurality of door handles comprised of lever, and associated latch mechanism pairs along with associated washers bushings and collar, that are all identical to those previously described are secured to the door so that all the door handles are aligned with each other and are attached to the same bus bar which is provided with a protrusion openings therethrough for this purpose. Protrusion openings can easily be made in the bus bar so that the door handles can be spaced apart as desired.
When the door handle system is thus installed in the door, for outward opening doors, the tongue will engage the door frame, as illustrated in FIGS. 2 and 3. However, a tongue receiving bracket is needed for inwardly opening doors, as illustrated in FIGS. 2A and 3A. The tongue receiving bracket is attached to the door frame in association with and for the purpose of being removably engaged by its associated tongue. The tongue receiving bracket is secured to the door frame on the side of the door frame where the latch mechanism is positioned when the door is closed. If the receiving bracket is made of sheet metal for mounting on the back side of the door facing, a reinforcing flange is provided on the receiving bracket to give it extra strength. Because the tongue and receiving bracket are both surface mounted to the inside of the door and door frame, respectively, the latch mechanism can be operated from either side of the door unless the door handle system has been locked in a closed position.
An L-shaped lock bracket with a lock opening provided extending through one leg of the bracket is secured to the front side of the door via a screw in association with one or more of the levers. The lock bracket is preferably provided with a counter-bored hole in its second leg into which a screw inserts to secure the lock bracket to the door facing. The hole is preferably counter-bored so that the head of the screw does not interfere with movement of the lever. Each lock bracket is secured to the door on the same side as the levers and is positioned so that the lock opening provided in the lock bracket is aligned with an associated lock opening provided in a distal end of the lever. When the two lock openings are aligned with each other, i.e. the two lock openings are aligned with each other only when the tongue is in its latched position, a link of a padlock can be insert through the two aligned lock openings, thereby locking the door handle system in its closed or latched position. In order to unlock the door handle system, the padlock is removed and then the levers are free to rotate to unlatch the tongues from their associated receiving brackets or door frames, thereby unlatching the door from its door frame. It should be obvious that because all of the levers and latch mechanisms of a given door handle system operated in conjunction with each other, all levers and latch mechanisms are rendered inoperative when any one of the levers is locked.
The arm of each latch mechanism is provided with an ear to prevent the latch mechanism from overextending when it is opened. The ear has an ear surface that positioned approximately perpendicular to a vertical lip provided on the bus bar whenever the latch mechanism is in its latched position. The ear surface engages the vertical lip when the latch is in its fully opened position, thereby preventing the latch mechanism from accidentally being rotated further than its fully opened position.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective rear view of a door handle system constructed in accordance with a preferred embodiment of the present invention shown in use on an outwardly swinging door.
FIG. 2 is a rear view taken along line 2 — 2 of FIG. 1 showing the door handle system in use with an outwardly swinging door.
FIG. 2A is a rear view of the same door handle system in use on an inwardly swinging door that is swung from the same side of the door frame as the door illustrated in FIG. 2 .
FIG. 3 is a rear view similar to FIG. 2 showing the door handle system in use on an outwardly swinging door that opens in a direction opposite to the direction of opening of the door illustrated in FIGS. 1 and 2.
FIG. 3A is a rear view of the same door handle system in use on an inwardly swinging door this is swung from the same side of the door frame as the door illustrated in FIG. 3 .
FIG. 4 is a cross sectional view taken along line 4 — 4 of FIG. 2 A.
FIG. 5 is a cross sectional view taken along line 5 — 5 of FIG. 3 A.
FIG. 6 is an exploded view of a single door handle of the door handle system shown in association with a door.
FIG. 7 is a side view of a lever of the door handle system.
FIG. 8 is a rear view taken along line 8 — 8 of FIG. 7 .
FIG. 9 is a side view of a first washer of the door handle system.
FIG. 10 is a rear view taken along line 10 — 10 of FIG. 9 .
FIG. 11 is a side view of a second bushing of the door handle system.
FIG. 12 is a front view taken along line 12 — 12 of FIG. 11 .
FIG. 13 is a side view of a collar of the door handle system.
FIG. 14 is a front view taken along line 14 — 14 of FIG. 13 .
FIG. 15 is a rear view of a latch mechanism of the door handle system.
FIG. 16 is a side view taken along line 16 — 16 of FIG. 15 .
FIG. 17 is an opposite side view taken along line 17 — 17 of FIG. 15 .
FIG. 18 is a top plan taken along line 18 — 18 of FIG. 15 .
FIG. 19 is a bottom plan taken along line 19 — 19 of FIG. 15 .
FIG. 20 is a side view of a snap bushing of the door handle system.
FIG. 21 is a rear view taken along line 21 — 21 of FIG. 20 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Invention
Referring now to the drawings and initially to FIG. 1, there is illustrated a door handle system 10 that is constructed in accordance with a preferred embodiment of the present invention. Although for ease of illustration and description, only two door handles 12 are illustrated in the door handle system 10 shown in FIG. 1, the invention is not so limited. The door handle system 10 attaches to a door 14 and employs a plurality of handles in the form of levers 16 for simultaneously latching and unlatching a plurality of associated latch mechanisms 18 . This system 10 is mounted externally to the front and back surfaces 20 and 21 , respectively, of the door 14 and the back surface 23 , respectively, of the door frame 24 so that the entire system 10 is readily visible and accessible for repair.
Referring now to FIG. 6, each lever 16 is paired with and attached to an associated latch mechanism 18 so that the latch mechanism 18 rotates in conjunction with its associated lever 16 . Each door handle 12 for the present system 10 is comprised of a lever 16 , its associated latch mechanism 18 , associated washers 56 and 100 , associated bushings 51 , 60 , and 101 , associated collar 40 , and associated screws 74 , 80 , and 98 , as will be more fully described hereafter.
As shown in more detail in FIGS. 7 and 8, each lever 16 is provided with a shaft 26 that attaches on a proximal end 28 of the lever 16 . The shaft 26 extends outward from the lever 16 so that a longitudinal axis 30 of the shaft 26 is approximately perpendicular to a longitudinal axis 32 of the lever 16 . Two opposite sides 34 and 36 of the shaft 26 are flattened along the length 38 of the shaft 26 . The purpose of the flattened sides 34 and 36 is so that the collar 40 and latch mechanism 18 , both of which are provided with shaft openings, 42 and 44 respectively, therein that are fitted to the shape of the shaft 26 . This means that each opening 42 and 44 has two flattened sides 46 and 48 , and therefore, neither the collar 40 or the latch mechanism 18 will rotate relative to the shaft 26 when they are slipped over the distal end 50 of the shaft 26 , but they will instead rotate in conjunction with rotation of the shaft 26 and its attached lever 16 .
A groove 52 is provided in the proximal end 28 of the lever 16 so that the groove 52 surrounds the proximal end 54 of the shaft 26 . A first washer 56 slips over the distal end 50 of the shaft 26 and is partially received within the groove 52 . The first washer 56 is preferably compressible so that it seals to the lever 16 and the door 14 to prevent air leakage between the door 14 and the lever 16 . The first washer 56 is shown in detail in FIGS. 9 and 10.
Next, a hollow snap bushing 51 is placed over the distal end 50 of the shaft 26 so that a cylindrical end 53 of the snap bushing 51 faces away from the lever 16 . The snap bushing 51 is illustrated in detail in FIGS. 20 and 21. An opposite end 55 of the snap bushing 51 is provided with a shoulder 57 which has a larger diameter 59 than a diameter 61 of the cylindrical end 53 . Then the shaft 26 is inserted through a handle opening 58 provided in the door 14 for this purpose, and the cylindrical end 53 of the snap bushing 51 enters the handle opening 58 and is secured therein by wings 63 that are provided on the cylindrical end 53 , with the shoulder 57 resting against the front surface 20 of the door 14 .
After the shaft 26 has been inserted through the handle opening 58 in the door 14 , a hollow second bushing 60 inserts over the distal end 50 of the shaft 26 so that a cylindrical portion 62 of the second bushing 60 extends through the handle opening 58 in the door 14 . The second bushing 60 , as illustrated in FIGS. 11 and 12, is provided with a shoulder 64 that has a larger diameter 66 than the diameter 68 of the cylindrical portion 62 , and this shoulder 64 engages the back surface 21 of the door 14 . Thus, the shaft 26 extends from a front side 72 of the door 14 to a back side 70 of the door 14 via handle opening 58 .
Next, the collar 40 , illustrated in detail in FIGS. 13 and 14, is slipped over the distal end 50 of the shaft 26 via its shaft opening 42 and is secured to the shaft 26 by a first screw 74 that inserts into a first screw opening 76 provided in the collar 40 approximately perpendicular to the longitudinal axis 30 of the shaft 26 . As previously described, the shaft opening 42 in the collar 40 is fitted to the shaft 26 , i.e. it is provided with two flattened sides 46 and 48 that engage the two flattened sides 34 and 36 of the shaft 26 as the collar 40 is slipped onto the distal end 50 of the shaft 26 . The collar 40 is provided with a second groove 77 similar to the groove 52 provided in the proximal end 28 of the lever 16 . The second groove 77 receives the shoulder 64 of the second bushing 60 . The first screw 74 is threaded into the first screw opening 76 until a tip 78 of the first screw 74 engages the shaft 26 , thereby securing the collar 40 to the shaft 26 and capturing the second bushing 60 , the door 14 , the snap bushing 51 , and the first washer 56 between the collar 40 and the lever 16 .
The shaft opening 44 of the latch mechanism 18 is next slipped onto the distal end 50 of the shaft 26 . The latch mechanism 18 is illustrated in FIGS. 15-19. The latch mechanism 18 is secured to the shaft 26 by a second screw 80 that inserts into a second screw opening 82 provided in the latch mechanism 18 approximately perpendicular to the longitudinal axis 30 of the shaft 26 .
Because the latch mechanism 18 is secured to the shaft 26 with the second screw 80 that can engage the shaft 26 anywhere along the length of the shaft 26 and because the shaft 26 can be made so that it is several inches in length, by simply adjusting the position of the latch mechanism 18 along the shaft 26 the door handle 12 can be used to accommodate doors 14 that are very thin or very thick.
As also previously described, the shaft opening 44 in the latch mechanism 18 is fitted to the shaft 26 , i.e. it is provided with two flattened sides 46 and 48 that engage the flattened sides 34 and 36 of the shaft 26 when the latch mechanism 18 is slipped onto the distal end 50 of the shaft 26 . The second screw 80 is threaded into the second screw opening 82 until a tip 84 of the second screw 80 engages the shaft 26 , thereby securing the latch mechanism 18 to the shaft 26 .
The latch mechanism 18 has a circular protrusion 86 provided on and extending outward from a rear side 87 of the latch mechanism 18 by which the latch mechanism 18 is attached to a bus bar 88 . The circular protrusion 86 is provided with a third screw opening 90 therein that is approximately parallel with the longitudinal axis 30 of the shaft 26 but is offset therefrom because the circular protrusion 86 is provided on a distal end 92 of an arm 94 of the latch mechanism 18 that extends outward approximately perpendicular to the longitudinal axis 30 of the shaft 26 .
As shown in the drawings, the arm 94 is offset from the tongue 104 . This offset positioning is important because it allows the latch mechanism 18 to be used with its front side 102 facing the door 14 , or alternately, flipped over so that its rear side 87 faces the door 14 .
The circular protrusion 86 is first inserted through a protrusion opening 96 created in the bus bar 88 for this purpose. Then a third screw 98 is first inserted through a large diameter second washer 100 , next through a bar bushing 101 , and then threaded into the third screw opening 90 to secure the latch mechanism 18 to the bus bar 88 . The bar bushing 101 is provided with a cylindrical end 103 that enters the protrusion opening 96 and receives internally the circular protrusion 86 , and the bar bushing 101 is provided with a shoulder 105 on an opposite end 107 that abuts the bus bar 88 .
When inserting the latch mechanism 18 onto the shaft 26 and before the latch mechanism 18 is attached to the bus bar 88 , either a front side 102 of the latch mechanism 18 can face faces the shaft 26 when the latch mechanism 18 is inserted onto the shaft 26 , as illustrated in FIGS. 2, 3 and 3 A, or alternately, a rear side 87 of the latch mechanism 18 can face the shaft 26 , as illustrated in FIG. 2A, when the latch mechanism 18 is inserted onto the shaft 26 . The circular protrusion 96 is provided on the rear side 87 of the latch mechanism 18 and it attaches to the bus bar 88 to operationally link the latch mechanism 18 of this door handle 12 to the latch mechanisms 18 of all of the other identical door handles 12 of the door handle system 10 .
The shaft opening 44 in the latch mechanism 18 is provided with two flattened sides 46 and 48 that can align with the two flattened sides 34 and 36 of the shaft 26 in two different ways simply by rotating the latch mechanism 18 while keeping the front side 102 of the latch mechanism 18 facing the door 14 . Therefore, when the latch mechanism 18 is facing the door 14 , it can be inserted on the shaft 26 in one of two ways so that the latch mechanism 18 can be employed to fit either right or left hand doors 14 , i.e. it can be inserted directly so that the flattened sides 46 and 48 of the shaft opening 44 of the latch mechanism 18 coincide with the flattened sides 34 and 36 , respectively, of the shaft 26 . Alternately, the latch mechanism 18 can be rotated 180 degrees before inserting it on the shaft 26 so that flattened sides 46 and 48 align, respectively, with sides 36 and 34 , respectively. In addition, the latch mechanism 18 can be flipped over 180 degrees so that the rear side 87 of the latch mechanism 18 faces the door 14 , as previously described. In this orientation, i.e. with the rear side 87 of the latch mechanism 18 facing the door 14 , the latch mechanism 18 can also be inserted on the shaft 26 in one of two ways, similar to the two different ways the latch mechanism 18 could be inserted on the shaft 26 when the front side 102 of the latch mechanism 18 faced the door 14 .
The latch mechanism 18 is provided with a wedge shaped tongue 104 that extends outward approximately perpendicular to the longitudinal axis 30 of the shaft 26 and is located in a plane parallel to a plane in which the arm 94 is located. A longitudinal axis 106 of the tongue 104 forms an obtuse angle, identified on the drawing as angle “A”, of approximately 140 degrees with a longitudinal axis 108 of the arm 94 . A pointed edge 110 of the wedge-shaped tongue 104 points away from the arm 94 .
A plurality of door handles 12 , each identical to door handle 12 previously described herein, are secured to the door 14 so that all the door handles 12 are aligned with each other and are attached to the same bus bar 88 into which properly spaced protrusion openings 96 have been created for this purpose. Protrusion openings 96 are drilled into the bus bar 88 so that the door handles 12 can be spaced apart as desired.
When the door handle system 10 is thus installed in the door 12 , for outward opening doors 12 , the tongue 104 will engage the door frame 24 , as illustrated in FIGS. 2 and 3. However, a tongue receiving bracket 112 is needed for inwardly opening doors 12 , as illustrated in FIGS. 2A and 3A. A tongue receiving bracket 112 is not necessary on outwardly opening doors 14 as the tongue 104 simply engages the door frame 24 to latch the door 14 closed. The tongue receiving bracket 112 is attached to the door frame 24 in association with and for the purpose of being removably engaged by its associated tongue 104 . The tongue receiving bracket 112 is secured to the door frame 24 via screws 114 or other suitable fasteners so that the tongue receiving bracket 112 is on the back surface 23 of the back side 116 of the door frame 24 where the latch mechanism 18 is positioned when the door 14 is closed. If the tongue receiving bracket 112 is made of sheet metal, an outwardly extending flange 113 is provided on the tongue receiving bracket 112 to strengthen it against bending. Because the tongue 104 and the tongue receiving bracket 112 are both surface mounted, i.e. surface mounted respectively to the back side 70 of the door 14 and to the back side 116 of the door frame 24 , the latch mechanism 18 can be operated from either side of the door 14 , i.e. the front side 72 or the back side 70 , unless, of course, the door handle system 10 has been locked in a closed position 118 . Also, employing this door handle system 10 , the door 14 can be opened either inwardly or outwardly and can be opened from either the left or right side.
An L-shaped lock bracket 120 with a lock opening 122 provided extending through one leg 123 of the lock bracket 120 is secured to the front side 72 of the door 14 via a lock screw 124 or other suitable fastener in association with at least one of the levers 16 . The lock bracket 120 is preferably provided with a counterbored hole 125 in its second leg 127 into which the lock screw 124 inserts to secure the lock bracket 120 to the door 14 . The hole 125 is preferably counterbored so that a head 129 of the lock screw 124 is recessed within the lock bracket 120 and does not interfere with movement of the lever 16 .
Each lock bracket 120 is secured to the door 14 on the same side of the door 14 , i.e. the front side 72 , where the levers 16 are located when the door 14 is in its closed position 118 . Each lock bracket 120 is positioned so that the lock opening 122 provided in the lock bracket 120 is aligned with an associated lock opening 126 provided in a distal end 128 of the lever 16 . When the two associated lock openings 122 and 126 are aligned with each other, i.e. when the tongue 104 is in its closed or latched position 118 , a link of a padlock (not illustrated) can be inserted through the two aligned lock openings 122 and 126 , thereby locking the door handle system 10 in its closed or latched position 118 . Also, when the lever 16 is in its locked position, the lever 16 covers the lock screw 124 , thereby preventing the lock bracket 120 from being removed from the door 14 in an effort to unlock the door handle system 10 without removing the padlock from the two aligned lock openings 122 and 126 .
In order to unlock the door handle system 10 , the padlock is removed from the lock openings 122 and 126 and then the levers 16 are free to rotate to thereby unlatch the tongues 104 from their associated tongue receiving brackets 112 , thereby unlatching the door 14 from its door frame 24 . It should be obvious that because all of the levers 16 and latch mechanisms 18 of a given door handle system 10 operated in conjunction with each other, all levers 16 and latch mechanisms 18 are rendered inoperative when any one of the levers 16 is locked.
The arm 94 of each latch mechanism 18 is provided with an ear 130 to prevent the latch mechanism 18 from overextending or rotating too far when it is opened. The ear has 130 an ear surface 132 that is approximately perpendicular to a vertical lip 134 provided on the bus bar 88 when the latch mechanism 18 is in its latched position 118 . The ear surface 132 engages the vertical lip 134 when the latch mechanism 18 is fully opened; thereby preventing the latch mechanism 18 from accidentally being rotated further than it's fully opened position.
While the invention has been described with a certain degree of particularity, it is manifest that many changes may be made in the details of construction and the arrangement of components without departing from the spirit and scope of this disclosure. It is understood that the invention is not limited to the embodiments set forth herein for the purposes of exemplification, but is to be limited only by the scope of the attached claim or claims, including the full range of equivalency to which each element thereof is entitled. | A door handle system for a door employing a plurality of door handles that operate in unison. Each door handle comprised of a lever with a perpendicular shaft, and the shaft extending through sequentially and securing together the following additional elements of the door handle to insure that the latch mechanism rotates together with the lever: a sealing washer, snap bushing, handle opening through the door, second bushing, collar and latch mechanism. An arm provided on each latch mechanism that attaches to a common bus bar. An outwardly extending tongue provided on each latch mechanism for engaging either a door facing or a tongue receiving bracket attached to the door facing to latch the door in a closed position. A lock bracket on the door with a lock opening to align with a lock opening provided the lever for padlocking the lever closed. | 8 |
CROSS REFERENCE TO RELATED APPLICATION
This application claims the priority of German Application No. 197 08 261.0 filed Feb. 28, 1997, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
This invention relates to a sawtooth clothing for a roll advancing fiber material, such as a feed roll which advances a fiber lap to a licker-in of a carding machine. The feed roll rotates slowly and forwards the fiber material with the leading tooth flanks, as viewed in the direction of roll rotation.
In a known sawtooth clothing for a feed roll, pointed teeth are provided and thus such clothing generally corresponds to the sawtooth clothing of the licker-in. The tooth height and the tooth gap height are relatively large so that the tooth gaps are filled with a substantial amount of fiber material. The tooth points are oriented opposite the direction of rotation of the feed roll; the back angle is approximately 30°. As a result of such a construction, the fiber material is pulled in as it sweeps over the trailing flank of the teeth, that is, in a somewhat force-locking manner which is disadvantageous as concerns the fiber advancing action. It is a further drawback that the tooth gaps are deep and are filled with a substantial amount of fiber material so that disadvantages may appear in measuring the thickness of the pulled-in fiber lap, particularly by virtue of the fact that only the small fiber part projecting beyond the tooth points is measured rather than the greater part of the fiber material which is situated in the tooth gaps.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved sawtooth clothing of the above type from which the discussed disadvantages are eliminated and which, in particular, makes possible an improved conveyance of the fiber material and a more accurate detection of the thickness fluctuations of the fiber material pulled in by the feed roll.
This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the roll for advancing fiber material has a roll surface provided with a sawtooth clothing which includes a plurality of teeth separated from one another by respective tooth gaps each having a gap bottom. Each tooth has a frontal flank oriented in a direction of roll rotation and a tooth point. Each tooth has a tooth height h 2 measured from the roll surface to the tooth point and a tooth gap height h 3 measured from the tooth gap bottom to the tooth point. The tooth height h 2 and the tooth gap height h 3 are small for defining a small fill volume between teeth. Each tooth has a back angle γ having a magnitude of at least approximately 90° and further has a large tooth division t and a large pitch P for defining a large open space about the teeth.
By virtue of the fact that the tooth height above the roll surface and the tooth gap height are small, a small fill volume for the fiber material in the tooth gaps is present, that is, the apparatus for measuring thickness fluctuations of the fiber material may detect the fiber material in its entire depth. The back angle having a magnitude of at least approximately 90° makes possible a form-fitting entrainment of the fiber material and therefore a significantly improved conveyance thereof towards the licker-in. The combination, according to the invention, of the shape of the teeth with the rectangular flanks and the above-noted small dimensions advantageously permits an improvement as concerns the delivery and the thickness measurement of the fiber material. Despite the small teeth the fiber material is, because of the large back angle, entrained in an effective manner, and because of the small teeth and tooth gaps it is possible to reliably detect the fiber mass during the measuring process. By providing that for achieving an open space about the teeth, the tooth division and the pitch are large, that is, wide and not deep, an undesired feed of the fiber material between the teeth and between turns (windings) of the clothing are avoided.
The invention has the following additional advantageous features:
The breast angle α is 0° or approximately 0°. The wedge angle β is 0° or approximately 0°. The tooth division t is approximately between 2.45 mm to 2.85 mm. The tooth gap is of approximately semicircular shape. The tooth gap at its opposite ends is approximately of quarter-circle configuration and the tooth gap has a planar bottom portion. The tooth length S (measured in the circumferential direction of the roll) is greater than 0.5 mm. The tooth gap height h 3 is approximately between 0.6 mm and 1.5 mm. The tooth height h 2 is approximately between 0.8 mm and 1.5 mm. The point width b S (measured parallel to the roll axis) is greater than 0.2 mm and smaller than 1 mm. The foot width b F (measured parallel to the roll axis) is greater than 1 mm and smaller than 4 mm and is preferably 2 mm. The tooth density T is approximately between 3.5 and 4.0 teeth/cm. The number of turns z is approximately between 4.8 and 5.2 teeth/cm. The tooth distribution density B over the roll surface is approximately between 18.5 and 19.5 teeth/cm 2 . The sawtooth clothing according to the invention may be used for example, as the delivery roll of a fiber tuft feeder for a carding machine or a cleaner or may be used as the intake roll for an opener or for a cleaner. The feed roll may be associated with a device for measuring thickness deviations of the conveyed fiber material.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side elevational view of a fiber processing assembly formed of a fiber tuft feeder and an after-connected carding machine, incorporating the invention.
FIG. 2 is an enlarged schematic sectional detail of the structure of FIG. 1 showing a feed roll which is disposed between the lower end of a feed chute of the fiber tuft feeder and a licker-in of the carding machine and which is provided with a clothing structured according to the invention.
FIG. 3 is an enlarged schematic side elevational detail incorporating the invention and showing a device for measuring thickness fluctuations of the fiber material.
FIG. 4 is an enlarged schematic side elevational detail of FIG. 1 showing a delivery roll of the fiber tuft feeder, cooperating with an opening roll and carrying a clothing structured according to the invention.
FIG. 5a is a side elevational view of a sawtooth clothing according to the invention, illustrated in a flat-lying (developed) state.
FIG. 5b is an axial sectional view of the sawtooth clothing according to the invention shown in a wound state (that is, installed on the roll surface).
FIG. 5c is a view similar to FIG. 5b, showing a variant from which the spacer wire of the FIG. 5b structure is omitted.
FIG. 5d is a fragmentary side elevational view similar to FIG. 5a, illustrating an approximately semicircular bottom of a tooth gap.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a carding machine 17 which may be an EXACTACARD DK 803 model, manufactured by Trutzschler GmbH & Co. KG, Monchengladbach, Germany. The carding machine 17 has a feed roll 1, a feed plate 2 cooperating therewith, licker-ins 3a, 3b, 3c, a main carding cylinder 4, a doffer 5, a stripping roller 6, cooperating crushing rolls 7 and 8, a web guiding element 9, a sliver trumpet 10, cooperating calender rolls 11 and 12, travelling flats 13 including flat bars 15, a sliver coiler 16 and a coiler can 14.
The slowly rotating feed roll 1 is provided with a sawtooth clothing structured according to the invention, to be described in more detail in conjunction with FIGS. 5a, 5b and 5c. Upstream of the carding machine a fiber tuft feeder 18 is arranged which supplies a fiber lap to the carding machine 17 and which may be a DIRECTFEED model, manufactured by Trutzschler GmbH & Co. KG.
As shown in FIG. 2, the slowly rotating feed roll 1 moves in the direction A while the rapidly rotating licker-in 3a moves in the direction B. The clothing 1' of the feed roll 1 is a sawtooth wire wound helically on the roll body 1". The feed roll 1 draws fiber tufts from the feed chute 30 of the card feeder 18 and advances the tuft through the clearance between the clothing 1' and the surface 2' of the feed plate 2 towards the licker-in 3a which further advances the fiber tuft. The licker-in 3a has a clothing which is formed of short needles 3'.
Turning to FIG. 3, the surface 2' of the throughgoing tray of the one-piece feed table 2 forms a clamping gap 19 with the clothing 1' of the feed roll 1. The feed table 2 is mounted on the machine frame and is biased by a spring 20 towards the feed roll 1, so that the feed table may resiliently yield in case particularly pronounced thickened portions of the running fiber material or foreign bodies are encountered. A holding element 21 which is biased by a spring 22 is also pivotally mounted on the machine frame for measuring and scanning the fiber material. The holding element 21 is a beam (summing beam) whose length is perpendicular to the plane of the drawing FIG. 3 and carries, along its length, a plurality of leaf springs 14 (only one is visible) which, at their upper end, are secured to the holding element 21 and in their lower end region serve as clamping springs for the fiber material, as they cooperate with the clothing 1' of the feed roll 1. Thus, during operation, the free (lower) end of the leaf springs 14 lifts off the end face 2" of the feed table 2 and the clothing 1' and applies a measurable torque to the beam 21. Such a device for measuring thickness fluctuations of the fiber material is disclosed in U.S. Pat. No. 5,479,679.
Turning to FIG. 4, upstream of the carding machine 17 a vertically oriented reserve chute 23 is provided which is charged at the top with finely opened fiber material. Such fiber supply to the reserve chute 23 may be effected via a condenser through a pneumatic supply and distributing duct 24. In the upper zone of the reserve chute 23 air outlet openings 25 are provided, through which transporting air G passes after being separated from the fiber tufts and enters into a suction device 26 as indicated by the arrow H. The lower end of the reserve chute 23 is obturated by a delivery roll 27 which cooperates with a tray surface 28. The delivery roll 27 is provided with a sawtooth wire clothing 27' which is constructed according to the invention and which is wound helically on the roll body 27'. The slowly rotating delivery roll 27 which moves in the direction C, advances the fiber material from the reserve chute 23 to a rapidly rotating opening roll 29 which is provided on its surface with pins 29' or with a sawtooth wire clothing and which, along a path of its circumferential surface, bounds a lower chute (feed chute) 30. The opening roll 29 moving in the direction D advances the fiber material (arrow I) into the feed chute 30 from which, in turn, the fiber material (arrow h) is drawn by the feed roll 1 for advancing the material to the carding machine 17. The licker-in 3 carries a sawtooth clothing 3".
Turning to FIG. 5a, the sawtooth clothing 1' is viewed in a line of sight which is parallel to the roll axis, that is, the roll axis is oriented perpendicularly to the drawing plane of FIG. 5a. For the sake of simplicity, the clothing wire is shown as extending linearly; it will be understood that in reality, it is helically wound about the roll 1, concentrically to the roll axis.
The clothing 1' has consecutive teeth 1' 1 , each having a height h 1 of, for example, 2.5 mm. Each tooth 1' 1 has a tooth point 1' 4 having a short straight zone S , for example 0.6 to 1.5 mm which extends parallel to the foot plane 1' 9 of the tooth foot 1' 2 . Further, each tooth 1' 1 has a tooth breast 1' 5 and a tooth back 1' 6 . The breast angle α is 0° or substantially 0°. The angle δ, that is, the angle between the straight zone of the tooth point 1' 4 and the line at the tooth breast 1' 5 perpendicular to the foot plate 1' 9 of the tooth foot 1' 2 is 90°. The back angle γ, that is, the angle between the straight zone 1' 4 and the line at the tooth back 1' 6 perpendicular to the foot plane 1' 9 is 90°. The tooth zone above the tooth foot 1' 2 is designated at 1' 3 . In each instance, between a tooth breast 1' 5 and a tooth back 1' 6 of two adjoining teeth 1' 1 a tooth gap 1' 7 is provided which has two arcs which have the approximate shape of a quarter-circle and which are interconnected by the planar gap base 1' 8 . The radii of the two arcs of the tooth gap 1' 7 are designated at r' Z and r" Z , and are of identical length which is approximately 0.6 mm. As an alternative to the planar gap base, the gap bottom may be cross-sectionally semicircular. The height h 3 of the tooth gap 1' 7 is approximately 0.6 to 1.5 mm, whereas the tooth division t is, for example, approximately 2.45 to 2.85. mm (in the straight wire). As shown in FIG. 5d, the bottom of the tooth gap 1' 10 is approximately semicircular.
FIG. 5b shows the sawtooth clothing 1' in a sectional view in which the line of sight is perpendicular to the roll axis which lies in the drawing plane of FIG. 5b. FIG. 5b shows two teeth 1' 1 which are thus axially spaced and which belong to two adjoining turns of the wire helix wound on the feed roll 1. The pitch between the two teeth is designated at P. Further, between the clothing helix a spacer wire 31 is helically wound on the roll body. It is feasible to omit the spacer wire 31 as illustrated in the variant shown in FIG. 5c. In such a case, no space between adjoining turns of the clothing helix is present. The axially measured tooth point width b S of the tooth 1' 1 may be, for example, greater than 0.2 mm and smaller than 1 mm. The axially measured foot width b F of the tooth 1' 1 (that is, the material thickness of the wire) may be greater than 1 mm and less than 4 mm, for example, 2 mm. The tooth density T=10/t may be, for example, about 3.5 to 4.0 teeth/cm. The pitch number z=10/b F may be about 4.8 to 5.2/cm. The tooth density over the surface of the roll=G×T may be about 18.5 to 19.5 cm 2 .
In operation, the fiber material (not shown) is advanced with the tooth back 1' 6 through the gap 19 (FIG. 3) towards the licker-in 3a. The tooth gaps 1' 7 are filled with fiber material, and the leaf springs 14 scan the fiber material which projects beyond the tooth gaps 1' 7 and tooth points 1' 4 .
The invention was, as an example, described in connection with the sawtooth clothing 1' of the feed roll 1 of the carding machine 17 and for the delivery roll 27 of a card feeder (fiber tuft feeder) 18. It should be understood that the clothing 1' according to the invention may find application in a take-in roll of an opener or cleaner in a fiber cleaning line as well.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. | A roll for advancing fiber material has a roll surface provided with a sawtooth clothing which includes a plurality of teeth separated from one another by respective tooth gaps each having a gap bottom. Each tooth has a frontal flank oriented in a direction of roll rotation and a tooth point. Each tooth having a tooth height h 2 measured from the roll surface to the tooth point and a tooth gap height h 3 measured from the tooth gap bottom to the tooth point. The tooth height h 2 and the tooth gap height h 3 are small for defining a small fill volume between teeth. Each tooth has a back angle γ having a magnitude of at least approximately 90° and further has a large tooth division t and a large pitch P for defining a large open space about the teeth. | 3 |
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