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CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to U.S. Provisional Patent Application No. 61/551,343, filed Oct. 25, 2011, the entire contents of which is incorporated by reference herein.
BACKGROUND
The present invention relates to a mining shovel, and in particular to an idler wheel assembly.
Front idler wheel assemblies are used in conjunction with machines, such as, among other applications, mining shovels, which utilize a straddle mount axle shaft support where the axle shaft is intended to rotate with the idler wheel. The current front idler wheel and idler axle shaft configuration utilizes a splined joint between the shaft and the wheel. The spline connection provides a torsional constraint between the two; however, the spline connection does not constrain the wheel from sliding axially from side to side across the splines. Side to side motion across the splines results in high wear between the components of the front idler wheel assembly. Furthermore, splined components found in the current idler wheel configurations are expensive to manufacture.
SUMMARY
In one embodiment, the invention provides a crawler assembly including a crawler frame member having an idler wall disposed between a first crawler extension and a second crawler extension. The idler wheel defines a bore therethrough. The crawler assembly additionally includes a shaft extending through the bore. The shaft is fixed relative to the wheel by a tapered interference fit and rotatable relative to the first and second crawler extensions. A first side of the shaft is received by the first extension and has at least one journal bushing disposed therebetween. Similarly, a second side of the shaft is received by the second extension and has least one journal bushing disposed therebetween. A removable endcap is secured to each of the first and second sides of the shaft such that a thrust surface is created at an interface between the endcaps and the journal bushings.
In another embodiment the invention provides a method of an idler wheel assembly including an idler wheel for attachment between a first extension and a second extension of a crawler frame. The wheel includes a bore that receives a shaft extending therethrough. A taper lock bushing is disposed between the shaft and the wheel such that the taper lock bushing creates an interference fit between shaft and the wheel. A first side of the shaft is received by the first extension and has at least one bushing disposed therebetween. Similarly, a second side of the shaft is received by the second extension and has a least one bushing disposed therebetween. A removable endcap is secured to each of the first and second sides of the shaft such that a thrust surface is created at an interface between the endcaps and the journal bushings.
In another embodiment the invention provides an idler wheel assembly including an idler wheel for attachment between a first extension and a second extension of a crawler frame. The wheel includes a bore and is coupled to a wheel hub having a tapered inner diameter. A shaft extends through the bore of the wheel and the hub. A portion of the shaft includes a tapered outer diameter that is complimentary to the tapered inner diameter, whereby the interference fit is created therebetween to fix the shaft relative to the wheel. A first side of the shaft is received by the first extension and has at least one journal bushing disposed therebetween. A second side of the shaft is received by the second extension and has a least one journal bushing disposed therebetween. A removable endcap is secured to each of the first and second sides of the shaft such that a thrust surface is created at an interface between the endcaps and the journal bushings.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is perspective view of a mining shovel.
FIG. 2 is perspective view of a front idler wheel assembly and a crawler frame of the mining shovel.
FIG. 3 is a perspective view of a front idler wheel assembly according to one embodiment of the invention.
FIG. 4 is a cross-sectional view of the front idler wheel assembly of FIG. 3 , taken along line 4 - 4 .
FIG. 5 illustrates a taper lock bushing shown in FIG. 4 .
FIG. 6 illustrates a lock mechanism of the taper lock bushing shown in FIGS. 4-5 , taken along 6 - 6 of FIG. 5 .
FIG. 7 is a perspective view of a front idler wheel assembly according to another embodiment of the invention.
FIG. 8 is a cross-sectional view of the front idler wheel assembly of FIG. 7 taken along line 8 - 8 .
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
DETAILED DESCRIPTION
FIGS. 1 and 2 illustrate a mining shovel 10 including a main platform 14 , a lower frame 18 , and a crawler assembly 22 . The crawler assembly 22 includes, in part, a first crawler frame member 26 and a second crawler frame member 30 , and constitutes a framework that supports motion of the mining shovel 10 . The first and second crawler frame members 26 , 30 each support a crawler track 50 on either side of the mining shovel 10 . Each of the crawler frame members 26 , 30 includes a first extension 54 and a second extension 58 , each with a rectangular opening 62 having a shim plate 66 and a shaft guard 70 positioned therein. The crawler frame members 26 , 30 each define a top of the crawler frame 38 and include a front idler wheel assembly 78 , carrier wheels 42 , and a rear driven crawler wheel 46 . Each front idler wheel assembly 78 includes a front idler wheel 34 , or a gear in some embodiments, positioned between the two extensions 54 , 58 of the respective frame member 26 , 30 and coupled to an idler axle 74 shaft for rotation therewith. The axle shaft 74 extends through a bore (not shown) in a center of the idler wheel 34 and through a bore (not shown) in each of the extensions 54 , 58 of the respective crawler frame member 26 , 30 .
FIGS. 3-6 illustrate one of the front idler wheel assemblies 78 according to an embodiment of the invention. The front idler wheel assembly 78 includes the front idler wheel 34 locked to the idler axle shaft 74 , which extends through a central bore (not shown) in the front idler wheel 34 . In the illustrated embodiment, the front idler wheel 34 includes a hub portion, although in further embodiments the wheel 34 may be a single piece. In the illustrated embodiment, a diameter 84 of the idler axle shaft 74 is smaller than a diameter 86 of the central bore of the front idler wheel 34 , which creates a small gap (not shown) therebetween during assembly. A taper lock bushing 90 is positioned within the gap. Due to extremely high radial loads applied through front idler wheel 34 during travel by the shovel 10 and as a result of the size of the components of the front idler wheel 34 and the idler axle shaft 74 , a pair of taper lock bushings 90 ( FIG. 4 ) are included in each front idler wheel assembly 78 . One bushing 90 is installed from either side of the idler wheel 34 . Access to the taper lock bushings 90 during assembly and disassembly is provided through the rectangular openings 62 of the first side 54 and the second side 58 of crawler frame members 26 , 30 . Additionally, each of the bushings 90 is covered by a contamination cap 88 , which keeps debris (i.e., water, dust, dirt) from the bushings 90 . The taper lock bushing 90 creates an interference fit, thereby locking the front idler wheel 34 to the idler axle shaft 74 . The interference fit provides a rigid connection that constrains the front idler wheel 34 and the idler axle shaft 74 axially, radially, and torsionally. Thus, the interference fit restricts the motion of the wheel 34 preventing high wear in the front idler wheel assembly 78 .
As is shown in FIGS. 5 and 6 , the taper lock bushing 90 includes a first inner member 94 , a second inner member 96 , and an outer member 100 . The inner members 94 , 96 have tapered outer surfaces 92 that are complimentary to and interface tapered inner surfaces 102 of the outer member 100 of the taper lock bushing 90 . Additionally, the taper lock bushing 90 includes two types of axially extending holes: full-length holes 118 and half-length holes 120 . The full-length holes 118 extend a length of the bushing 90 . Holes 118 are defined by a through-hole portion 118 a , which extends through the first inner member 94 of the bushing 90 , and a threaded hole portion 118 b , which extends through the second inner member 96 of the bushing 90 . Holes 120 are threaded and extend through the first inner member 94 of the bushing 90 ; therefore, the holes 120 extend approximately half way through the bushing 90 and do not have a portion defined in the second inner member 96 . In the illustrated embodiment, there are a pair of holes 118 for every one hole 120 , with one hole 120 positioned between adjacent pairs of holes 118 . The full-length holes 118 are assembly holes while the half-length holes 120 are disassembly holes.
During assembly of the front idler wheel assembly 78 , fasteners 104 (e.g., screws) are used to create an interference fit between the front idler wheel 34 and the idler axle shaft 74 . The interference fit is accomplished by tightening the fasteners 104 . The fastener 104 is inserted into the through-hole portion 118 a of the respective hole 118 and screwed into the threaded portion 118 b of the hole 118 . As the fastener is screwed into the threaded portion 118 b , the two members 94 , 96 of the bushing 90 are pulled closer together. As the two members 94 , 96 are brought closer together, the tapered outer surfaces 92 slide in relation to the tapered outer surfaces 102 of the outer member 100 , thereby pushing the outer member 100 radially outward and the inner members 94 , 96 radially inward. As such, an outer diameter 108 of the bushing 90 radially expands, while an inner diameter 112 of the bushing 90 radially contracts. Expansion of the outer diameter 108 of the taper lock bushing 90 against the inner diameter 86 of the central bore of the front idler wheel 34 and simultaneous contraction of the inner diameter 112 of the taper lock bushing 90 against the idler axle shaft 74 creates the interference fit between the wheel 34 and the shaft 74 . The expansion and contraction of the lock bushing 90 also produces significant surface pressure between the front idler wheel 34 and the idler axle shaft 74 , thus locking them together and into position.
During disassembly of the front idler wheel assembly 78 , the fasteners 104 may also be used to disassemble the taper lock bushing 90 . After all of the fasteners 104 are removed from the assembly holes 118 , some of the fasteners 104 are tightened into the other set of holes 120 . As the fasteners 104 are tightened into the half-length holes 120 , the fasteners 104 contact the second member 96 . Because that portion of the member 96 does not have a hole, tightening of the fastener 104 pushes the second member 96 away from the first member 94 so that the tapered outer surfaces 92 of the inner members 94 , 96 slide in relation to the tapered outer surfaces 102 of the outer member 100 . This movement causes the outer member 100 to move radially inward and inner members 94 , 96 to move radially outward. Therefore, the outer diameter 108 of the bushing 90 radially contracts while the inner diameter 112 of the bushing 90 radially expands. Thus, the bushings 90 are returned to their loose fit starting positions. While the front idler wheel components are assembled, the unlocking holes 120 , which are threaded, are used to couple the contamination cap 88 to the taper lock bushing 90 . Fasteners 110 occupy the holes 120 , thereby coupling the contamination cap 88 to the bushings 90 . The contamination cap 88 protects the bushings 90 from debris that fills the opened unlocking holes 120 , cause the tapered surfaces 92 and 102 to rust tight, and inhibit loosening and removal of the bushings 90 .
The extensions 54 , 58 , of the crawler frame members 26 , 30 lend lateral support to both sides of the front idler wheel 34 because the idler axle shaft 74 extends through the central bore (not shown) of the front idler wheel 34 and through a bore (not shown) in each of the two extensions 54 , 58 . Referring to FIG. 4 , the axle shaft 74 is received by and rotates relative to two journal bushings 124 positioned on opposite sides of the idler wheel 34 . Each of the bushings 124 is fixed to a bushing block 128 that is attached to the respective extension 54 , 58 of the crawler frame members 26 , 30 . Each of the bushing blocks 128 includes a recess 132 for lubrication lines to lubricate the journal bushings 124 . Fasteners 136 , or connectors, couple axle end caps 140 to the idler axle shaft 74 for rotation therewith, and the fasteners 136 extend through shims 144 . A thrust surface 146 is located at an interface between the journal bushings 124 and the axle end cap 140 . In the illustrated embodiment, the axle end caps 140 wear against the journal bushings 124 as a result of side thrust forces that are introduced to the front idler wheel 34 as the shovel 10 moves and pivots. As increased wear occurs on the journal bushings 124 , the axle end caps 140 are removed to replace the journal bushings 124 without disassembling the entire front idler wheel assembly 78 . Furthermore, the shims 144 in between the idler axle shaft 74 and the axle end caps 140 may be removed to reduce the gap between the journal bushings 124 and axial end caps 140 , as the journal bushings 124 wear away.
FIGS. 7 and 8 illustrate a front idler wheel assembly 278 according to another embodiment of the invention. The front idler wheel assembly 278 of FIGS. 7 and 8 is similar to the front idler wheel assembly 78 of FIGS. 3-6 ; therefore, like structure will be identified by like reference numbers plus “200” and only the differences will be discussed hereafter.
The front idler wheel assembly 278 includes an idler axle shaft 274 , which extends through a central bore (not shown) of a wheel hub 348 coupled to a front idler wheel 234 . The wheel hub 348 , which is coupled (e.g., by welding) to an inner diameter 286 of the wheel 234 , fills a gap (not shown) between the front idler wheel 234 and the idler axle shaft 274 . Referring to FIG. 8 , both the axle shaft 274 and the wheel hub 348 include a tapered portion, 352 and 356 respectively, of the diameter, which are complementary to each other. An angle of taper of the tapered portions 352 and 356 of both the idler axle shaft 274 and the wheel hub 348 is approximately 3.6°. However, in further embodiments, the angle of taper could be greater or less than 3.6°.
During assembly, a substantial force is applied using an external device in the direction of arrow 360 to drive mating components, the front idler wheel 234 and the idler axle shaft 274 , axially together; thereby creating significant surface pressure. The surface pressure keeps the front idler wheel 234 and the idler axle shaft 274 fixed together after the force is removed and during operation of a mining shovel 10 . The tapered surfaces of the axle shaft 274 and the idler wheel hub 348 provide the interference fit therebetween, thereby providing a rigid connection to constrain the front idler wheel 234 and the idler axle shaft 274 axially, radially, and torsionally. The interference fit is accomplished by manufacturing both the axle shaft 274 and idler wheel 234 with a small degree of taper on the mating diameters. Thus, the interference fit restricts the relative motion of the wheel 234 and the idler axle shaft 274 preventing high wear in the front idler wheel assembly 278
In a further embodiment, the front idler wheel assembly does not include a wheel hub and the inner diameter of the idler wheel is manufactured with a tapered surface. An interference fit is created between the front idler wheel and the tapered axle shaft by mating the tapered surfaces of the two components.
Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described.
Thus, the invention provides, among other things, a rigid connection between components of an idler wheel assembly thereby preventing sliding wear on joint surfaces by restricting movement of the idler wheel and rotating axle shaft radially, axially, and torsionally. Various features and advantages of the invention are set forth in the following claims.
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A crawler assembly including a crawler frame member having a first crawler extension and a second crawler extension and an idler wheel disposed therebetween. The idler wheel defines a bore therethrough. The crawler assembly includes a shaft that extends through the bore. The shaft is fixed relative to the wheel by a tapered interference fit and rotatable relative to the first and second crawler extensions. A first side of the shaft is received by the first extension and has at least one journal bushing disposed therebetween. A second side of the shaft is received by the second extension and has a least one journal bushing disposed. A removable endcap is secured to each of the first and second sides of the shaft. A thrust surface is created at an interface between the endcaps and the journal bushings.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation application of U.S. application Ser. No. 12/321,425, filed Jan. 21, 2009, now U.S. Pat. No. 7,891,970, which is a divisional application of U.S. application Ser. No. 10/527,364, filed Apr. 27, 2005, now U.S. Pat. No. 7,504,059, which claims the benefit of International Application No. PCT/NL2003/00630, filed on Sep. 10, 2003, which claims priority to NL1021421, filed Sep. 10, 2002.
BACKGROUND OF THE INVENTION
The invention relates to an apparatus for manufacturing products from an at least thermoplastically deformable material. Such a method is known, for instance, as injection molding.
With known injection molding techniques, as a rule, the material to be formed such as plastic is heated in a plasticizing device to a temperature such that the material becomes virtually liquid, at least plastic and low-viscous, whereupon the material is introduced under high pressure into a mold cavity of an injection molding mold. In this mold cavity, the material is distributed such that the mold cavity is completely filled, whereupon the material is allowed to cure by cooling down. Thereupon, the product is taken out by opening the mold and ejecting the product.
For such known injection molding techniques, a particularly high feed pressure is to be used, especially when thin-walled products are formed, in particular if the flow paths in the mold cavity closely approach the melt flow index (MFI) of the materials to be used. Therefore, the same holds in particular when the flow paths in the mold cavity are relatively long. It is clear that with plastics with a high viscosity and/or a low melt flow, these problems occur to a larger extent. As a result, limitations are imposed on the minimum and maximum sizes of products, in particular on lengths of flow paths, on passage widths of such flow paths, on the duration of the injection molding cycles, on the materials to be used and on the minimum wall thicknesses of products, in particular of large, flat parts.
The use of compression molding is already known. Here, into a mold cavity of a partly open mold, an amount of plastic is introduced, required for forming a desired product in this mold cavity. After the plastic has been introduced into the mold cavity, the mold is closed further, so that the plastic is pushed away for filling the further mold cavity. Therefore, with such an apparatus, at the start of the introduction of the plastic, the mold parts are to be held partly away from each other, and only afterwards to be brought onto each other relatively slowly but with high pressure. The danger exists that then, the plastic is not uniformly distributed, so that, for instance, a part of the material can be pressed sideways from the mold cavity before the mold cavity is completely closed. Also, the danger exists that insufficient or, conversely, too much plastic is introduced into the mold cavity. In this latter case, skin formation will occur between the mold halves and, moreover, it will not be possible to close the mold completely. This leads to irregularly formed products and, moreover, to pollution of the mold. A further disadvantage of this apparatus is that when materials are used with a low viscosity and/or with shallow mold halves, the material flows from the mold cavity before the mold halves are moved together, so that the earlier mentioned problems occur to an even larger extent.
SUMMARY OF THE INVENTION
The object of the invention is to provide an apparatus of the type described in the opening paragraph, wherein in a simple manner and with relatively low closing pressures, products can be manufactured having at least parts with a relatively limited wall thickness.
A further object of the invention is to provide an apparatus of the type described in the opening paragraph, wherein different materials can be processed, in particular plastics, in particular also plastics with a high melt, i.e. plastics with a low viscosity in plastic state.
A still further object of the invention is to provide a method with which, in a relatively rapid and simple manner, products can be manufactured, with relatively simple means, which products, moreover, can have relatively large, thin-walled surfaces, in particular products with wall thicknesses which are relatively small and flow paths which are relatively long, smaller or longer, respectively, than matching the melt flow index associated with the material from which the product is manufactured.
The invention further contemplates providing an improved use of an injection mold with a slide.
A number of these and many other objects are achieved with an apparatus, method and/or use according to the invention.
An apparatus according to the invention is characterized by a mold with at least one mold cavity; wherein in the or each mold cavity at least one movable part, to be called slide, is provided; movement means for moving the slide; closing means for opening and closing the mold such that the mold cavity is released or closed, respectively; feed means for introducing, with the mold cavity closed, said material in at least substantially plastic condition into the mold cavity; wherein the movement means for moving the slide are arranged for moving said slide forward in the mold cavity at a relatively high speed relative to the movement speed of the mold parts upon their opening and closing, from a position at least partly retracted from the mold cavity, such that, as a result, said material is displaced in the mold cavity for obtaining the filling thereof, said slide moving at a speed sufficiently high such that adiabatic heat development occurs in the mold cavity.
With an apparatus according to the invention, a thermoplastic material such as a plastic, in particular a thermoplastic plastic, can be introduced into a mold cavity while the mold as such is closed and the or each slide is in, or is being brought into, a retracted position at introduction of the material, so that the volume of the mold cavity is relatively large with respect to the volume of the product to be eventually formed. After the material has been introduced entirely or, preferably, substantially into the mold cavity, the or each slide can be moved forcefully and, in particular, with speed into the mold cavity, at least into the material introduced therein, so that this is pushed away. With it, a speed is developed such that, as a result of the movement of the or each slide, heat development occurs in the material. To that end, the movement means are designed such that the slide can move at the desired high speed and with the desired accuracy.
Preferably, the movement means and the slide are designed such that adiabatic heat development occurs, so that the temperature in the material rises above the melting temperature of the respective material.
In an advantageous embodiment, the closing means are included at least partly in or on the mold, preferably such that no press is required or that a press without guide rod can suffice. Optionally, also, blocking means can be provided on the mold for holding the mold in closed condition during introduction of the material and displacement of the or each slide.
With an apparatus according to the invention, the mold can be held closed with relatively little closing pressure and the plastic can be introduced, in comparison with a conventional injection molding apparatus. By way of illustration: with conventional injection molding, feed pressures of between, for instance, 350 bars and 1000 bars or more are used, with closing pressures of, for instance, 0.25 to 1.25 ton/cm 2 , depending on, in particular, the material used, the wall thickness and the maximum flow path. With a method according to the invention, for comparable products, a feed pressure of, for instance, between 0 and 200 bars excess pressure can suffice, while relatively low pressures are preferred, for instance of some tens of bars or less. In the Table, an operating pressure of approximately 300 bar (operating pressure of the cylinders of the slides) is given, while the closing pressure can be, for instance, less than 0.2 ton/cm 2 . With polypropylene, for instance, a closing pressure of 0.025 to 0.1 ton/cm 2 instead of between 0.25 to 1.25 ton/cm 2 can suffice.
Without wishing to be bound to any theory, this appears, in particular, to be the result of the insight that by temporarily increasing the volume of the mold cavity, at least when introducing the larger part of the material such as the plastic into the mold cavity, the relation between the length of the flow paths and their passage, substantially determined by the minimum wall thickness of the product to be formed, becomes more favorable, so that the material experiences relatively little counter pressure in the mold cavity, while the injection opening or openings are so small that upon movement of the slide or slides, the material is not pushed back through this opening or these openings. Moreover, then, the advantage appears to be achieved that due to the high speed of the or each slide, as a result of friction, so much heat is introduced into the material that solidification of the material, in particular against the mold parts and in the flow front thereof, is undone so that the viscosity of the material is reduced again, while the remaining length of the flow paths for this flow front at the start of the movement of the or each slide has been considerably reduced relative to the original length thereof. As a result, the material can be distributed in the entire mold cavity with less pressure. As the mold is then closed, in a simple manner, the material is prevented from flowing away prematurely.
Surprisingly, it has appeared that then, a high feed rate is particularly advantageous. For instance, a feed rate can be used of between 100 and 2000 mm/s, more in particular of between 500 and 1000 mm/s. This rate is selected depending on the solidification rate of the plastic used, while it holds that the more quickly the plastic solidifies, the higher the feed rate is chosen to be. Moreover, the rate is selected depending on the mold geometry and, in particular, the de-aeration, such that undesired pressure increase in the mold cavity by compression of air is prevented.
With a mold according to the invention, in the movement means, preferably, wedge-shaped elements are used which, viewed from the mold cavity, are moved behind the or a slide, such that the respective slide is moved as a result of the wedge-shape. In particular, then, for each slide at least two wedge-shaped elements are used which are pushed in opposite directions behind the slide so that a symmetrical load is obtained. Through the use of such wedge-shaped elements a favorable distribution of forces is obtained and the slides can be moved over the desired distance with relatively little force.
In a mold according to the invention, preferably, at least one slide is provided at the location where the smallest wall thickness is provided in a product and/or at the location where the flow paths have the greatest length and/or at the location where the flow paths have the greatest complexity. By retracting the slides in those parts upon injection of the plastic, at least moving them partly from the mold cavity, additional space is created for allowing the plastic to pass exactly at the location where the plastic experiences the most resistance or at the location where excessive pressures would be necessary for allowing the plastic to pass. This holds in particular at the location where already some solidification of the plastic occurs. The adiabatic heat introduced later causes the plastic to flow further, while, moreover, the displacement of the slide effects the further movement of the plastic. Furthermore, with such a mold, relatively large, thin-walled product parts can be obtained with wall thicknesses that cannot be obtained with conventional injection molding technique.
Slides in a mold according to the invention can have a frontal surface which is relatively large in relation to the projected surface of the product. Herein, projected surface is understood to include the surface of the product projected on a plane at right angles to the closing direction of the mold. For instance, the frontal surface of the slide can be more than 20% of this projected surface. Surfaces of more than 50%, for instance of 75%, 85% or 95% or more are possible. With this, the advantage is achieved that in a major part of the mold cavity, the space for primary flow of the material to be formed is increased, while, eventually, thin-walled products can be manufactured. As a result of this as well, the feed pressure and the closing pressure can be kept even lower.
The invention further relates to a method for forming products, wherein, in a mold cavity, an amount of plastic is introduced in substantially plastic condition, whereupon at least one movable element to be called a slide is moved at least partly into the respective mold cavity while compressing and/or displacing at least a part of the plastic, while the speed of movement of the at least one slide is so high that adiabatic heat development occurs in the plastic, such that the plastic becomes more liquid, at least its viscosity is decreased.
With such a method, in a rapid and simple manner, plastic products can be manufactured, while low pressures can be used for injection of the plastic as well as closure of the mold. As low injection pressures can be used, the advantage can be achieved that no undesired chemical or mechanical changes occur in the plastic, in particular separation in the different monomers or polymers, while the closing pressure can be kept low, which is advantageous from a point of view of costs. The fact is that for that purpose, simpler apparatuses are suitable, while moreover, the mechanical load is lower and less wear will occur. A further advantage thereof is that, in principle, less space is required for such an apparatus.
With a method according to the invention, plastic is introduced into the mold cavity while the or each slide is retracted therefrom at least partly or is pushed back upon injection, so that additional flow space is obtained. This has already been discussed hereinabove with reference to an apparatus according to the invention. Thus, the resistance the plastic experiences is reduced, so that the injection pressure can be kept low, for instance largely below the standard injection pressure for conventional injection molding of a similar type of product from the same plastic. Such standard pressures can be read from standard tables and, as a rule, are dependent on the plastic and the manner of injection, the projected surface of the products to be formed jointly and the wall thicknesses. As a result thereof, the closing pressure can also be kept low in relation to conventional injection molding, readable from the same or comparable tables on the basis of substantially the same quantities. This is directly clear to the skilled person.
With a method according to the invention, after the mold cavity has been at least substantially filled, the or each slide is moved rapidly into the mold cavity, such that the eventual product shape is obtained. The speed of the or each slide is then set such that adiabatic heat development occurs in the plastic, so that the temperature is increased again to approximately the melting temperature of the plastic. As a result, partially solidified material will become liquid again and be pushed further into the mold cavity, while, furthermore, the remaining flow paths are relatively short so that relatively thin product parts can be formed.
With a method according to the invention, the rate of movement of the or each slide is preferably high, such that the complete movement of the slides is carried out in a fraction of the cycle time of a product cycle, for instance in less than 10%, more in particular in less than 3% of the cycle time, preferably less than some tenths or hundredths of seconds, more in particular microseconds. As stated, this rate is set such that the desired temperature increase occurs, while the plastic properties are prevented from being adversely thermally influenced.
With a method according to the invention, the distance between the end of the or each slide, leading in the direction of movement and facing the mold cavity in the retracted position, at least partly moved from the mold cavity, and an oppositely located wall part of the mold cavity or slide is set depending on at least the melt of the plastic, i.e. the viscosity of the plastic upon injection. Surprisingly, it has appeared that, preferably, at a higher melt, i.e. a higher viscosity, the distance is to be slightly greater than with a lower melt. Without wishing to be bound to any theory, this appears to be the result of the fact that the plastic with the higher melt will solidify sooner and the plastic with the lower melt has a more disadvantageous MFI. For any plastic/mold combination, the optimal distance can be determined in a simple manner by way of experiments.
The invention further relates to a use of a mold for forming products, and a product.
BRIEF DESCRIPTION OF THE DRAWINGS
In clarification of the invention, exemplary embodiments of an apparatus, method, use and product will be described with reference to the drawing. In the drawing:
FIG. 1 shows, in partly cross-sectional side view, an apparatus according to the invention, with partly opened mold;
FIG. 2 shows, in partly cross-sectional side view, an apparatus according to the invention, with a closed mold and retracted slide;
FIG. 3 shows, in partly cross-sectional side view, an apparatus according to the invention, with a closed mold and forwardly moved slide;
FIG. 4 shows, in partly cross-sectional side view, an alternative embodiment of an apparatus according to the invention;
FIG. 5 is a graph showing the temperature in the plastic in a mold according to the invention during an injection molding cycle, plotted against time; and
FIG. 6 shows a depiction of a CD-box manufactured according to the invention, photographically recorded using colorant.
FIG. 7 shows, in partly cross-sectional side view, an apparatus according to the invention with two mold cavities, each having a slide;
FIG. 8 shows, in partly cross-sectional side view, an alternative embodiment of an apparatus according to the invention with two mold cavities.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In this description, identical or corresponding parts have identical or corresponding reference numerals. The embodiments shown are only given by way of example and should not be taken as being limitative in any way.
FIG. 1 shows, in cross-sectional side view, an apparatus 1 according to the invention, provided with a mold 2 with a mold cavity 3 therein. The mold comprises a first, moveable part 4 and a second, complementary part 5 , fixedly arranged. The moveable part 4 is guided by suitable guides, which are not shown but can, for instance, be sliding pins, rails, guide rods or a press or the like and which are directly clear to the skilled person. The moveable part is moveable with the aid of devices suitable to that end, represented in FIGS. 1-3 as piston-cylinder assemblies 7 . It is clear that this may be any suitable device, for instance also a simple press, screw means such as spindles as shown in FIG. 4 , link systems or the like. These can be of relatively light design as they are only meant for moving the part 5 , virtually not for absorbing tensile or pressure forces in the further cycle.
In the fixed part 5 , a slide 8 is provided, moveable in the direction S between a retracted position shown in FIGS. 1 and 2 , and an extended position shown in FIG. 3 . For moving the slide 8 , two wedges 9 are provided, to be called wedge-shaped elements, which are moveable in a direction P with the aid of piston-cylinder assemblies 10 which are, for instance, hydraulically driven from a central control unit 11 . The wedges 9 move in the direction P approximately at right angles to the direction S. At the underside, the slide 8 is provided with two surfaces 12 inclining in opposite directions, complementary to the top surfaces of the wedges 9 , such that if the wedges 9 are moved inwards, towards each other, the slide 8 is moved upwards (directions viewed in the plane of the drawing) towards the extended position and vice versa.
An inflow opening 14 terminates in the mold cavity 3 and is connected to an injection device 15 , for instance a plasticizing device and, optionally, a pressing device. On both parts 4 , 5 of the mold 2 , flanges 16 are provided which, with the aid of blocking means 17 , can be pressed and held onto each other, for keeping the mold closed. To that end, in the embodiment shown, the blocking means comprise brackets 18 which are moveable with the aid of piston-cylinder assemblies 19 and can be pushed over the flanges 16 . In this way, simply, the desired closing pressure can be obtained and maintained.
As an example, on the top surface 20 of the slide 8 , two ribs 21 are provided extending over the entire width of the slide 8 , at right angles to the plane of drawing. The distance D between the end 22 of the ribs leading in the direction of movement, and the oppositely located surface 23 of the mold cavity is set with the slide 8 retracted, depending on the desired product wall thickness and the plastic to be used, while the distance is set to be larger according as the melt of the plastic is higher and/or the melting temperature of the plastic is lower.
With an apparatus according to FIGS. 1-3 , a product can be formed, for instance a sheet with two hinges from thermoplast such as polypropylene or polyethylene, as follows.
The mold 2 is closed from the position shown in FIG. 1 , as shown in FIG. 2 . The distance D is then set at a suitable value, such that the space in the mold cavity 3 is relatively great. Through the inflow opening 14 , under relatively low pressure, plastic is introduced into the mold cavity, for instance at a pressure of between 1 and 10 bars excess pressure. The filling pressure is selected such that a desired, short feed time is achieved without the material properties of the plastic being adversely affected and without undesirably high pressure occurring in the mold cavity. Then, at a relatively high speed, the slide 8 is moved forward, in the direction of the extended position, a shown in FIG. 3 , by moving the wedges 9 . Here, the speed is selected dependent on the desired adiabatic heat development which should be such that the temperature of the plastic is at least substantially increased to approximately the melting temperature thereof. Plastic that is, possibly, slightly solidified becomes liquid again and can be forced further into the mold so that a complete filling of the mold cavity is obtained while the product can have wall thicknesses which are, in fact, too small for the melt flow index of the respective plastic/product combination. Optionally, after removing the slide, some hold pressure can still be given with the aid of the injection device 15 , so that undesired stresses can be pressed from the product.
After that, the mold can be opened again and the product can be taken out.
Preferably, the rate of movement of the or each slide is high such that the time of movement of the slide between the retracted and the extended position is relatively short with regard to the cycle time for the manufacture of a product, for instance between 0 and 10% of that time, also depending on the desired adiabatic heating. This can be determined by way of an experiment for each plastic-product combination or be calculated with the aid of standard tables regarding plastics, the product properties such as dimensions and flow paths, the friction which will occur when moving the slide and the heat capacity and melt temperature of the plastic.
In FIG. 4 , an alternative embodiment of an apparatus according to the invention is shown, wherein screw spindles 25 with nut blocks 26 are used for opening and closing the mold 2 . These can be wholly or partly included in the mold 2 . In this embodiment, the plastic is introduced via a side inflow opening 14 and a slide 8 is provided on both sides of the mold cavity 3 . In this embodiment, they can be moved independently of each other but it is preferred that they be moved in coupled relation, so that a symmetrical load occurs in the mold 2 .
By way of illustration, an embodiment of a mold and method according to the invention will be described. As a product example, a plastic file is taken. In Table 1, the data of the injection molding machine are included, in Table 2 the mold data, in Table 3 the product dimensions, in Table 4 the data about the slides or pressure plate and in Table 5 data involving the operation parameters. In Table 6, the pressures and speeds used during an injection molding cycle are given. Thereupon, in FIG. 5 , the temperature in the plastic in a mold according to the invention during an injection molding cycle is given, plotted against time.
TABLE 1
Machine Data
Machine
Stork SX 3000-2150
Machine Number
X 2936
Year of Construction
2000
Main Feed
400 V 50 Hz
Main Current
354
A
Control Voltage
24
V
Max Oil Pressure
210
bar
Max Air Pressure
8
bar
Weight Closing Force
8700
kg
Weight Injection Force
5000
kg
Screw diameter
65
mm
TABLE 2
Mold Data
Length
1050 mm
Width
455 mm
Height
495 mm
Number of Cavities
1
TABLE 3
Product Size
Length
655 mm
Width
320 mm
Thickness
1.7 mm
TABLE 4
Pressure Plate Data
Cylinder Stroke
50
mm
Cylinder Diameter
80
mm
Operating Pressure
300
bar
Wedge Angle
4°
TABLE 5
Parameters
Mold Temperature
50°
Temperature at Introduction
245°
Dosing
128
mm
Shot Weight
295
gram
Impact of the Pressure Plate
80
mm
Decompression
10
mm
Closing Force
150
ton
Hold Pressure
25
bar
Thrust
20
bar
Speed of Impact
0.4
S
TABLE 6
Cycle Time
Sub Time
At Time
Total Time
Closing
0.750 S
T = 0.000
S
0.750 S
Injection
0.171 S
0.750
S
0.921 S
Impact Pressure Plate
0.400 S
0.857
S
1.257 S
Cooling
12.000 S
1.257
S
13.257 S
Opening
1.000 S
13.257
S
14.257 S
Handling
5.000 S
14.257
S
19.257 S
With a method according to the invention, at a time 0 , with the mold closed, an amount of plastic was introduced into the mold cavity, sufficient for manufacturing an end product, in this case a file. In 0.1706 sec, a shot weight of 128 grams of PP was introduced into the mold cavity. The mold cavity comprised a slide with a frontal surface of approximately 200,000 mm 2 , which was moved over a distance of 1.8 mm. The plastic was introduced, at a temperature of approximately 245° C. at a speed of 750 mm/s, without pressure, at a mold temperature of approximately 50° C., and was cooled down in a first phase to approximately 230° C. At the time T 1 , after approximately 0.107 seconds, the slide was set in motion, which slide was moved completely forwards in approximately 0.4 sec, while the temperature in the mold rose to just below the temperature at which the plastic will decompose. From the time T 2 , at which the slide was completely moved forward and was held in that position, the plastic was allowed to cool down to a temperature well below the melting temperature, close to room temperature, for instance 45 to 55° C. This cooling down was done in approximately 12 seconds. Apart from two living hinges, the product thickness on the covers and the back was on average 1.7 mm by, viewed in frontal surface, 655 mm by 320 mm. During cooling down, the application of hold pressure was not necessary, as a result of the fact that no shrinkage needed to be absorbed. The product appears to be free of stress, so that a high form-stability is obtained.
As a result of the high speed of the slide, kinetic speed is converted to heat, while, moreover, friction between the plastic and the mold as well as in the plastic itself and the compression leads to adiabatic heat development. Until approximately the moment T 2 the slide is completely moved forward, the plastic in the mold is kept in motion and, furthermore, kept above the melting temperature, so that solidification is prevented and the flow behavior of the plastic is positively influenced. As a result, a complete filling of the mold cavity is obtained with limited closing force and filling pressure.
The mold was moved with wedges with a wedge angle of approximately 4°.
With a method according to the invention as described herein, the slide is already moved to the extended position while the plastic is being injected into the mold cavity. This also contributes to the plastic being kept in motion.
In FIG. 6 , a photographic depiction is given of a CD-box manufactured with a method according to the invention. Here, the flow pattern of the plastic is clearly visible. FIG. 6 is to be explained as follows.
With conventional injections, a tangle of lines would be visible. With conventional injecting, these lines are caused by plastic being supplied under pressure. A very dark, confused pattern becomes visible and indicates the presence of stresses in the material. Conversely, in this picture, a particularly quiet image presents itself with attractive, long threaded light patterns. A slight hold pressure causes the two dark spots around the points of injection. In itself, this hold pressure is not necessary but hold pressure can be advantageous for further improving the product, in particular the flatness thereof. The slightly darker spots near the center are the result of this hold pressure which, clearly, has remained particularly limited.
The invention is not limited in any manner to the embodiments represented in the drawing and the description. Many variations thereon are possible within the framework of the invention as outlined by the claims. For instance, a mold 2 according to the invention can comprise several mold cavities, while the or each mold cavity can be provided with one or more slides, as shown in FIGS. 7 and 8 . The slides can be driven in different manners, for instance directly, as shown in FIG. 7 , instead of by the wedges, as shown in FIG. 8 , and with the aid of different means, for instance electrically. Also, the slides can move in different directions, for instance approximately at right angles to the direction of movement of the mold parts, or be pivoted for reducing the space in the mold cavity.
These and many comparable adaptations are possible within the framework of the invention as outlined by the claims.
Although the illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention.
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An apparatus for manufacturing products from material which is thermoplastically deformable, as from plastic, comprising: —a mold ( 2 ) with at least one mold cavity ( 3 ); —in the or each mold cavity ( 3 ) at least one slide ( 8 ); —movement means for moving each slide ( 8 ); —closing means for opening and closing the mold ( 2 ); —feed means for introducing, with the mold cavity ( 3 ) closed, said material in at least substantially plastic condition into the or each mold cavity; wherein the movement means ( 9 ) for moving the slide ( 3 ) are arranged for moving said slide forward at a relatively high speed relative to the movement speed of the mold parts upon opening and closing thereof, from a position at least partly retracted from the mold cavity, such that said material, as a result, is displaced in the mold cavity for obtaining the filling thereof, preferably at a speed high such that adiabatic heat development occurs in the or each mold cavity.
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[0001] This invention claims priority to German Patent Application No. 10 2004 034 235.0, filed Jul. 15, 2004.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates to an elastic seal for the static sealing of plastic components in the field of internal combustion engines, for example, existing cylinder head gaskets made from plastic. In particular, the present invention concerns an integrated seal with a component part of this type.
[0004] 2. Related Art
[0005] Thin-walled lids for internal combustion engines, such as, for example, valve covers or cylinder head gaskets include elastic seals for static sealing. The known seals are, as a rule, buttoned-in or vulcanized directly at the cylinder head gasket. With the vulcanized seals, the elastomer either is injected into an available groove and mechanically clamped (DE 42 02 860) or clamped in closed form (DE 197 38 275) or joined by an adhesive to the surface (GB 12 63 077).
[0006] In the field of internal combustion engines there is, however, an increasing need at present for seals which are joined firmly with sealing component parts. Integrated seals of this kind have the advantage, that larger system components can be delivered prefabricated in a so-called module. The joining or, respectively, integration of seal and component part and lid demonstrates strong technical advantages such as the form stability of the seal, advantageous handling during production and assembly, etc. Typical component parts to which the seals are directly injection molded in order for the joining of component parts and seals to be achieved mainly comprise component parts such as, for example, cylinder head gaskets or oil pans made from die-cast metal or steel sheets. For directly injection-molded seals of this kind, an adhesive agent is conventionally used which brings about the necessary binding of between metal and (die-cast or (steel-) sheet) and seal.
SUMMARY OF THE INVENTION AND ADVANTAGES
[0007] Component parts made from plastic, which are distinguished, above all, by their lower density make up in increasing mass for their counterparts of metal providing that a weight reduction is obtained, which directly favorably affects the fuel consumption of the internal combustion engine. Up to now, directly injected seals of this type of existing plastic component parts of internal combustion engines are not in use.
[0008] It is an object of the invention to make available with a directly injection-molded seal a component part made from existing plastic. In particular, it is an object of the invention to provide by direct injection molding an existing cylinder head gasket made from plastic or, respectively, an integrated seal.
[0009] The problem is solved according to the present invention by providing a lid component part of an internal combustion machine with integrated elastic seal, as for example, a cylinder head gasket or oil pan. The component part exhibits a circular flange area for the structuring of the integrated seal. The component part is based on a plastic-material, while the seal is formed substantially from an organic elastomer material. The component part and the seal are chemically bound with one another.
[0010] In accordance with the invention the flange area is formed substantially in an L-shape, so that the seal is arranged with its sealing profiled element on a seal surface of the surface area. Furthermore, the seal encompasses the lateral flange area, so that the seal is at least partially arranged on the upper flange surface.
[0011] Preferably the component part is prepared from polyamide. Advantageously, the elastomer material of the seal exhibits a Mooney-viscosity ML (1+4) at 100° C. in a range of about 20 to 100 and particularly in a range of about 25 to 50. Especially, the organic elastomer material is a rubber such as, for example, a fluorinated rubber or an acrylate rubber. Preferred are organic elastomer materials from polyacrylate (ACM) or ethylene acrylate (AEM). Advantageously, a crosslinking system of organic elastomers is based on hexamethylenediaminecarbamate or N,N′-di-ortho-tolylguanidine. According to the invention, the chemical binding between the component part and the organic elastomer material of the seal can be effected by an adhesive.
[0012] Preferably, the component part is formed of thin-walls.
[0013] In accordance with the invention, the flange area can display one or more passages, with which the organic elastomer materials of the seal are filled, so that a part of the seal arranged on the seal surface is mechanically capable of coupling with a part of the seal arranged on the upper flange surface. Furthermore, according to the invention the component part possesses one or more blocking structures, which are encompassed by the seal.
[0014] Preferably, the seal is applied by means of injection molding upon the component part.
[0015] In accordance with the invention, a method is provided in order for a lid component part with integrated elastic seal of an internal combustion engine to be manufactured, such as for example, a cylinder head gasket or oil pan. The component part with a circular flange area for the disposition of the seal is provided and the existing seal made from an organic elastomer material is applied by means of a pick tool. The component part and the seal undergo a chemical bonding with one another.
[0016] Preferably, the pick tool is so formed that the resulting seal with its seal gasket is arranged on a seal surface of the surface area, and encompasses the lateral flange area, so that the seal is at least partially arranged on the upper flange surface. For this, the flange area is formed substantially in L-shape. Furthermore, the component part can be provided preheated at a temperature in a range from about 100° C. to 150° C.
THE DRAWINGS
[0017] The invention is more closely explained by means of the following exemplary drawings which refer to a specific embodiment of the invention. The drawings show:
[0018] FIG. 1 a first schematic perspective sectional view of a component part with integrated seal according to a specific embodiment of the invention;
[0019] FIG. 2 a second schematic perspective sectional view of the component part according to FIG. 1 with screw connection point; and
[0020] FIG. 3 a third schematic perspective sectional view of the component part according to FIGS. 1 and 2 with screw connection point and aspect on the seal gasket.
DETAILED DESCRIPTION
[0021] In the figures, as well as in the description, the same reference numerals are used, in order to designate the same or similar component parts or elements.
[0022] By reference to FIG. 1 an existing plastic component part of an internal combustion engine with an integrated seal according to a specific embodiment of the invention is explained by example. The displayed component part frame of FIG. 1 could concretely be a lid, a cylinder head gasket, an oil pan or the like. The integrated seal equipped component part is designated in general as 100 in the figures, while the injection molded seal, which in this embodiment is set out by example as a double-lipped seal, is designated as 200 in the figures. The sealing profiled element of the double-lip seal is named as 210 in the figures.
[0023] Of course, sealing profile elements with a seal lip or several seal lips are possible.
[0024] The component part 100 , that is exemplicative of the lid, the cylinder head gasket, the oil pan, etc. is prepared as described above from plastic, preferably made out of polyamide. Elastomers are used as sealing substances, especially preferred are selected organic elastomers but no conventional inorganic elastomers such as, for example, silicone are used. From the domain of the organic elastomers, above all, rubbers such as, for example, fluorinated rubber (FPM), acrylate-rubber, polyacrylate-acrylic resin, polyacrylate (ACM) ethylene acrylate (AEM) are used. For the injection process, among other things, the viscosity of the useful organic elastomers and particularly the Mooney-viscosity, that is, a measure of the sheer viscosity, is to be considered. According to material choice and Shore A hardness the Mooney-viscosity ML (1+4) of the organic elastomers, measured at 100° C., cost-effectively should lie in a range from about 20 to 100. In order for a chemical bonding between the existing plastic component parts and the injected seal made from AEM or ACM to be ensured, the Mooney-viscosity (ML(1+4) at 100° C.) with this choice of materials should be in the range of about 25 to 50.
[0025] The bonding of the plastic component parts and seal made from elastomer can result through direct adhesion joining together of the materials or with the aid of an additionally supplied adhesive. Alternatively, the plastic of the component part and/or the elastomer can be modified, in order to enable the adhesion, in the form for example, of a chemical bond.
[0026] Moreover, for a chemical bond between component part and injection-molded seal, preferably a suitable crosslinking system of the elastomers is to be chosen, which enters into chemically compatible and suitable chemical bonding. For an existing polyamide component part the crosslinking system would be designed on the basis of hexamethylene diamine carbamate and N,N′-Di-ortho-tolylguanidine, in order to insure the chemical bonding of the polyamide with the elastomer.
[0027] A good chemical bond between the plastic component part and the injection-molded seal is additionally guaranteed preferably by preheating of the component part. Conveniently, the component part I heated to a temperature in the range of about 100° C. to 150° C. before the injection of the seal, that is, before the injection process.
[0028] In conclusion, it is to be noted that the combination of plastic of the component part and elastomer of the seal, is provided for integration with the component part, the requirements of the use environment having to be satisfied. That is, the requirements among others, are determined for the selection of the material and/or elastomers. In particular, temperature demands, creep effects of the material (component part materials, seal-materials) and stiffness are to be taken into consideration. Also to be considered is the combined effect of the component part with the other component part, against which the sealing should take place or against whose surface the sealing should occur. Particularly of interest in this connection are variable physical properties of the materials used for the component parts in this connection. Therefore, the existing-plastic, integrated seal-equipped component part seals against a component part manufactured from metal, whereby the physical properties particularly in respect to the temperature-contingent varying expansion-properties and varying rigidity properties, are to be taken into consideration.
[0029] In combination with the above-described chemical bonding of the injection-molded seal based upon an organic elastomer to the component part made from plastic, an advantageous novel geometry of the component part with integrated seal is proposed within the scope of the present invention. The novel geometry concerns the flange area of the component part, in which the integrated seal is arranged. By reference to FIG. 1 in the perspective sectional view, a cross-sectional surface 120 of the component part is shown. The flange area of the component part is formed with a generally L-shaped projection towards periphery, i.e. the flange surface is generally L-shaped. The projection is characterized in general as 130 in the figures.
[0030] The flange area has a lower flange surface, also designated in the following as a sealing profile element, which in the assembled state of the component part is directed in line to a seal opposite surface of an opposite or counter component part (not shown) and an upper flange surface which is arranged parallel to the lower surface and is directed in the assembled state path of seal opposite surface of the opposite or counter component part.
[0031] The seal is wrapped around the flange surface. This means that the seal, whose seal element profile is arranged out of the seal element profile surface, laterally encompasses towards periphery the L-shaped protrusion of the flange surface, so that a lateral flange surface of the L-shaped protrusion of the surface area of the seal is covered, and is arranged at least partially overlapping the upper flange surface of the L-shaped protrusion of the surface area. On the upper flange surface a sealing-off edge 300 is provided, up to which the elastomer-material of the seal is led and with which the seal preferably terminates flatly upwards there. Furthermore, the seal also displays a sealing edge 310 , on which the arranged sealing element profile runs.
[0032] That the seal laterally encompasses the flange area also has the advantage, that the seal or, respectively, the seal element profile can be arranged more in line to the lateral edge of the component part, so that the flange area can be better utilized. This is not the case, if the seal had been completely arranged on the sealing element profile surface or, respectively, on the lower flange surface and had been imprinted there accordingly on both sides. In the proposed geometry of the invention, the seal is only one-sided, and the lateral opposite edge is imprinted.
[0033] The tool or the pointed tool for the deployment of the injected seal with the above-described seal geometry is provided with imprinted areas in correspondence with the sealing-off edge 300 on the upper flange surface and a sealing edge 310 on the lower flange surface or, respectively, the sealing element profile surface. In the imprint areas the tool seals off during the injection processes against the component part, so the seal geometry explained above, which provides an encirclement of the surface area, is obtained.
[0034] For the mechanical reinforcement of plastic component parts, as they are discussed here, often additional reinforcement ribs 110 or other reinforcement structures of equal function are inserted, in order to strengthen the flange area of the component part, and to ensure and/or to improve the sealing effect of the seal. Exemplarily, a reinforcement rib 110 is illustrated in FIG. 1 . The encompassing or encircling seal encompasses the flange or encircles the reinforcement rib 110 , which also is encircled by a sealing-off edge 305 , which stands in connection with sealing-off edge 300 .
[0035] The above-explained tool or pointed tool is adjusted in correspondence with the course of the sealing-off edges 300 and 305 , in order to enable the above explained encirclement of the reinforcement ribs 110 , or respectively, the reinforcement structures by means of the seal geometry.
[0036] FIG. 2 shows a second schematic perspective sectional view of the component part corresponding to the specific embodiment illustrated in FIG. 1 . The sectional view displayed in FIG. 2 shows in essence a top view on the upper flange surface and a specified screw point 150 in the component part to this assembly.
[0037] For exemplary illustration the component part with three reinforcement ribs 110 is provided, which shows in each case a sealing-off edge ( 305 ) adjusted to the geometry of the reinforcement ribs 110 and is encompassed by the seal as described above.
[0038] The screwing point 150 shows exemplarily a possibility, to provide an eye area or an implementation, by means of which the component part can be fastened to the counter component part. Advantageously, the screwing point 150 serves for the leading through of a screw which is screwed into the counter component part, in order for the component part with the sealing element profile of the seal to be fixed against the counter component part. For the fixation, a predetermined jacking force is usually set. For mechanical stabilization and/or reinforcement, such a screwing point 150 can be provided with a reinforcement 140 such as, for example, a hollow shaft, which preferably can be manufactured from a plastic or metal material. Such grommets or screwing points 150 are advantageously arranged substantially in the flange area, so that the predetermined jacking force, which is created by the fixation of the component part by means of the screwing points 150 , directly acts as much as possible on the seal or the sealing element profile.
[0039] In addition, with implementations of this kind (or, respectively, screwing points 150 ) decoupling elements for acoustic decoupling of the component part of the counter component part and/or separator can be provided. The decoupling elements or, respectively, the separator thereby can be injected together with the seal or be formed from one other material with contingent differing Shore A hardness. The decoupling element or, respectively, the separator can subsequently also be provided integrated.
[0040] In conclusion, FIG. 3 shows a third schematic perspective sectional view of the component part corresponding to the specific embodiment illustrated in FIG. 1 or 2 .
[0041] The sectional view displayed in FIG. 3 shows in essence a top view on the sealing element profile, i.e. the lower flange surface, and the screwing point 150 with hollow shaft 140 .
[0042] In the perspective sectional view of FIG. 3 the double-lipped profile of the seal is clearly recognizable. The seal is led around in the area of the screwing point 150 around the screwing point 150 with hollow shaft 140 . With sufficient space the seal is conducted around as seal lips. However, alternatively it is also possible, at points of constriction, particularly in the area of screwing points, such as the screwing point 150 to bring together the sealing element profile in the form of double lips, so that at least area-wise the sealing element profile is implemented as single lip. Equivalents are also certainly valid for multi-lipped embodiments of the sealing element profile, which can be brought together to double-lips at constriction points in reduced number.
[0043] Advantageously, the flange surface is provided with additional pathway 220 . Such pathways can be filled, for example, during the injection process for the combination of the seal with the elastomer, so that an immediate coupling of the applied seal on the upper flange surface and the applied seal on the lower flange surface is obtained, which effects a stabilization of the seal geometry supplementary to the bonding of seal and component part. Alternatively, a mechanical fixation of the seal in the above-described action can also be obtained by means of an additional fixation element, which intervenes in the pathway 220 or takes vigorous action through the pathway 220 .
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A lid component part of an internal combustion engine with integrated elastic seal, such as, for example, is provided to a cylinder head gasket or oil pan and a process for its manufacture. The component part exhibits a circumferential flange area for the arranging of the integrated seal. The component part is based on a plastic-material, while the seal essentially comprises an organic elastomer material. The component part and the seal are chemically bonded with one another. The seal is applied by injection molding onto the component part.
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TECHNICAL FIELD
[0001] The invention relates to durable polishes having improved abrasion resistance. In particular, the invention relates to durable polishes containing silicone and alumina, bentonite clay or silica nanoparticle components for protection of painted metal and plastic surfaces.
BACKGROUND
[0002] The invention improves upon current technology for the protection of painted metal and plastic surfaces from the effects of environmental exposure. Automotive finishes, boats, aircraft and other surfaces are exposed to ultraviolet radiation, acid rain, wind erosion due to entrained dust and sand, corrosion, and other harsh elements. The value of the vehicle is reduced when the surface finish is pitted or low in gloss. The present invention adds new protection to the polishes that are currently available for these applications while still allowing ease of application and surface preparation.
[0003] There is a wide range of products available for the protection of painted surfaces. Some focus on ease of application, but this usually leads to a loss of long-term protection. Products intended for long-term protection are often difficult to apply, requiring special equipment or extensive surface preparation. Additionally, many products on the market have been formulated at less-than-optimal composition to avoid infringement of existing patents. This leads to suboptimal performance by the product.
[0004] The present invention combines components used in many conventional polish systems with new materials in novel compositions that enhance the protection and gloss of treated surfaces, while still allowing ease of use. Further, the compositions disclosed herein impart improved abrasion resistance to the treated surface without compromising either the ease of application or the long-term performance of the polish.
SUMMARY
[0005] This invention relates to a novel protective finish that increases the useful life of the surfaces to which it is applied. The finish combines reactive aminosilicone resins and fluids with anhydrous aluminum silicates and bentonite clay. When nanoparticles of silicon, clay or alumina are used in the finish, they are better able to penetrate into microcracks and micropores in the painted surface. This penetration reinforces the surface of the paint, seals it against penetration by oxidizing elements and reduces its tendency to scratch or abrade. These components also increase the impact toughness of the finish, reducing the effects of particulate impact on the coating.
[0006] The use of perfluoroalkyl oligomers can enhance the oil resistance and improve the gloss of the surface as well. When combined with the nanoparticle fillers, which scatter light less than previous particles, the transparency of the coating is improved and the color of the paint is enhanced. Further, the impact resistance and resistance to chipping is improved.
DETAILED DESCRIPTION
[0007] A detailed description of one of the preferred embodiments of this patent follows. This description does not limit the compositional variation claimed, nor does it limit future compositional variations.
[0008] In one embodiment, the polish is a colloidal suspension having the following composition:
Weight Percent Component Range Water 60-70 Anhydrous aluminum silicate (KAOPOLITE ™) 3-10 WITCAMIDE ™ 511 or similar emulsifier 0.5-1.5 Mineral spirits 18-25 Aminofunctional silicone fluids 4-7 (e.g. Dow Corning 531 Fluid, Dow Corning 536 Fluid or Dow Corning 200 fluid) Reactive silicone resin (Dow Corning Z-6018) 0.5-1.5 Anhydrous ethyl alcohol 1.0-2.0 BENTONE ™ 38 organoclay stabilizer 0.3-0.7 Anhydrous isopropyl alcohol 0.2-0.4 Perfluoroalkoxy-perfluoroethylene copolymer 0.25-1.5 Perfluoroalkyl oligomer 0.0-1.0 Boric oxide particles 0.01-0.10
[0009] In one embodiment of the invention, the polish is prepared as follows:
1. Combine the water and the KAOPOLITE™ in a high shear mixer. 2. Add the WITCAMIDE™ 511 emulsifier and the mineral spirits to the mixture in the high shear mixer and mix until uniform. 3. In a separate container dissolve the reactive aminofunctional silicone fluids in the anhydrous ethyl alcohol, then dissolve the reactive silicone resin into this solution. 4. Add the ethyl alcohol solution of the reactive silicone components to the aqueous dispersion above. 5. Once the aqueous dispersion has become a uniform paste, add the organoclay stabilizer, the anhydrous isopropyl alcohol, the perfluoroalkoxy-perfluoroethylene copolymer, the perfluoroalkyl oligomer and the boric oxide particles. Continue mixing until a uniform paste is again obtained.
[0015] In one embodiment of the invention, the surface to be protected is prepared as follows:
1. The surface is washed with an aqueous solution of detergent. This removes surface dirt and oils and allows maximum wetting and bonding of the polish to the surface. 2. If desired, the surface may then be etched slightly using an oxalic acid solution. This removes surface oxidation from the finish and further improves adhesion of the polish to the surface.
[0018] The polish typically is then applied to the cleaned surface using a sponge or cloth applicator and wiped over the surface until a uniform film is obtained. The polish is then wiped off the surface using a clean soft towel and a second coat of polish is wiped onto the surface. The second polish coat is then buffed with a clean terrycloth towel or buffing pad to achieve a durable high-gloss finish.
[0019] Although the present invention has been shown and described with reference to the foregoing operational principles and preferred embodiments, it will be apparent to those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention. The present invention is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims.
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Durable polishes having improved abrasion resistance that contain silicone and alumina, bentonite clay or silica nanoparticle components for protection of painted metal and plastic surfaces.
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FIELD OF THE INVENTION
The field of the invention relates to control systems, particularly those used for hydraulically controlling subsurface safety valves.
BACKGROUND OF THE INVENTION
In the past, subsurface safety valves ("SSV's") have been controlled from hydraulic control systems from the surface. Hydraulic control systems are commonly used on production rigs for control of surface safety components. The SSV is located at or adjacent the base of the wellbore, or in a location immediately above the producing zone at the time. In emergency situations, a rapid shutdown of the SSV is required. The SSV's of prior designs have been actuated by movable sleeves, which have in turn been actuated by a hydraulic system from the surface. In applications involving great depths, the auxiliary tubing, run adjacent the production string for control of the SSV, develops considerable hydrostatic head pressures at the control mechanism downhole adjacent the SSV. To compensate for the developed static head pressures from the control fluid column in the control tubing, springs or other compensating devices have been used to counteract such forces. In these designs, the SSV remains closed until additional pressure is developed in the control tubing from the surface to overcome the spring force, thereby directing the control tubing pressure to shift the sleeve in order to open the valve. These systems were set to be failsafe because upon withdrawal or loss of the control system pressure, the spring acting on the piston would result in movement of the piston, with the final resulting action being the shifting of the sleeve, allowing the SSV to close.
Typical of such designs is U.S. Pat. No. 4,173,256. In that design, a spring biases a piston against the hydrostatic head in the tubing control line from the surface. Once the pressure is raised beyond the resistance of the spring and hydrostatic pressure from the annulus, the piston is displaced, compressing the spring and control pressure is communicated to the sliding sleeve to open the SSV. The SSV sleeve is spring-biased against production tubing pressure so that it retracts upon removal of control pressure, allowing the SSV to slam shut. Once the control pressure is removed, the spring in the control system pilot valve pushes the piston to close off the control fluid supply line and to vent the accumulated fluid adjacent the shifting sleeve behind the pilot valve piston into an area in fluid communication with the annulus.
One of the problems of the prior designs, particularly for applications involving significant well depths, was that high operating pressures were required for the control system in order to initiate movement of the sliding sleeve in the production tubing, as well as the pilot valve piston in the control system, for actuating of the SSV. The pilot piston spring had to resist higher hydrostatic heads in the control line due to the greater depth. Typically in these deep-well applications, the hydraulic control system used for other surface emergency components, would be of an insufficient pressure rating for the pressures typically required in a control system for an SSV which may be mounted 8,000-15,000 ft below the surface. Accordingly, operators would have to use discrete hydraulic control systems rated for the desired operating pressures for the sole purpose of actuation of the SSV. This involved additional expense to the rig operator. It also created space problems on the rig where space for operational components is at a premium. The hydraulic control systems used for surface components generally operated in the pressure range of between 1,000-3,000 psi. The pressure requirements for the SSV at deep installations could be as high as 10,000-15,000 psi. The higher pressure system required pipe and fittings rated for the higher pressure service and precluded the use of the standard hydraulic control systems normally present in a rig.
The apparatus and method of the present invention presents a configuration where the hydrostatic forces from applications at large depths have become inconsequential due to a balanced design for the actuation system. The actuation system is exposed to production tubing pressure on opposing surface areas of approximately equal area, thus putting the actuation mechanism in a force balance until the balance is upset by application of control pressure from the surface, triggering movement of the SSV. In another feature of the invention, the need for occasional purging of control fluid from the control system of an SSV is accomplished. Purging is particularly beneficial because uses of water-based control line fluids have increased sensitivities to contamination and breakdown. Traditional systems for control of SSV's from the surface involve systems that have a fixed volume, as opposed to one where the control fluid is circulated. A circulating system would require a pair of control lines down to the SSV and would increase complications in installation and operation. Without the ability to do purging or circulation, the control fluid could prematurely fail and damage control system components such as seals. In another feature of the apparatus and method of the present invention, a shuttle valve has been designed which facilitates the operation of the control system and, for each cycle of opening and closing the SSV, purges a fixed amount of control fluid from the system so that premature failure of system components such as seals does not occur.
SUMMARY OF THE INVENTION
The invention relates to a control system for an SSV. A pressure-balance feature is introduced such that the control system components are unaffected by the depth of placement of the SSV. Through the use of this feature, the standard hydraulic control system used for surface components can also be used for an SSV regardless of its depth of installation. In another feature of the invention, a shuttle valve is provided so that each time the SSV is stroked, a volume of control fluid is purged into the annulus. One embodiment of the shuttle valve may or may not be sensitive to annulus pressure and employs annulus pressure as an aid to stroking the shuttle valve upon application of surface control pressure to assist in actuation of the SSV, while at the same time providing for a purge of a controlled volume of fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A-C is a sectional elevational view of one of the features of the present invention, illustrating the pressure-balance actuating system, showing the SSV in the open position.
FIG. 2A-D is a detailed view showing the control lines and their routing in the embodiment shown in FIG. 1A-C.
FIG. 3 is a schematic representation of the shuttle valve of the present invention.
FIG. 4 is an alternative design for the shuttle valve shown in FIG. 3.
FIG. 5 is a hydraulic diagram of the operation of the shuttle valve and control system, of which it is a part.
FIG. 6 is the control system of FIG. 5, with applied control pressure from the surface prior to any venting to the annulus.
FIG. 7 is the control diagram of FIG. 6 with sufficient surface pressure applied to actuate the SSV.
FIG. 8 is the hydraulic diagram of FIG. 7, with hydraulic pressure from the surface retained in the system to maintain the SSV in an open position.
FIG. 9 is the hydraulic diagram of FIG. 8 showing the release of control pressure from the surface with the resulting realignment of the flowpaths, representing a condition with the SSV being in a closed position.
FIG. 10A-C is a sectional elevational view of one of the features of the present invention, illustrating the pressure-balance actuating system, showing the SSV in the closed position.
FIG. 11 is a view along line 11--11 of FIG. 2A.
FIG. 12 is a schematic representation of the control system in use with a collection chamber.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
One feature of the apparatus A of the present invention is shown in FIGS. 1A-C and 10A-C. FIGS. 1A-C and 10A-C are actually two different positions of the apparatus A of the present invention, as can be seen by comparing FIGS. 1C and 10C. The SSV B is in the open position (FIG. 1C), with sleeve 10 shifted downwardly until it contacts shoulder 12 to maintain the SSV B open in a manner known in the art. Similarly, the retraction of sleeve 10 to the position shown in the other view of FIG. 10C allows the SSV B to close via the urging of spring 14.
Control line pressure is applied to the apparatus A through port 16. Traditionally this is done by auxiliary tubing (not shown) run from the surface outside the production tubing (not shown), which is typically connected at thread 18. Port 16 communicates with cavity 20. Piston 22 is disposed in bore 24, with seals 26 and 28 sealing therebetween. A lug 30 is formed at the lower end of piston 22. Lug 30 conforms to a cutout 32 on connector 34. Connector 34 has another cutout 36 which accommodates lug 38 on piston 40. Piston 40 rides in bore 42 and is sealed off against bore 42 by seals 44 and 46. As seen in FIGS. 2C and D, bore 42 is in fluid communication with conduit 48, with conduit 48 leading to control line 50. Control line 50 leads into housing 52. Ultimately, line 50 and connection 54 are tied into the shuttle valve V of the present invention, schematically illustrated in FIGS. 3 and 4.
Connector 34 is in contact with tab 56 on sleeve 10. Sleeve 10 also has a tab 58 with spring 60 bearing on it. Spring 60 supports the weight of sleeve 10 and is compressed by tab 58 when the SSV B is in the open position.
As previously stated, the production tubing (not shown) is connected at threads 18. The flowpath 62 extends through the production tubing from the surface down to the SSV B. Connector 34 is exposed to the pressure in the production tubing flowpath 62. The symmetrical construction of connector 34, as well as pistons 22 and 40, puts connector 34, as well as pistons 22 and 40, in pressure balance with respect to the applied pressure in the flowpath 62. As will be described below, an increase in pressure in port 16 shifts the assembly of pistons 22 and 40 downwardly, which in turn moves connector 34 in the same direction. Connector 34 bearing down on tab 56 shifts sleeve 10 downwardly to open the SSV B. In order to close the SSV, pressure conditions are created such that the pressure in chamber 20 is less than conduit 48 which, by virtue of relaxation of spring 60, shifts sleeve 10 upwardly so that the SSV which had previously been held open can spring shut through the operation of spring 14. The apparatus A of the present invention as previously described is different than prior systems which employed a single piston cylinder combination, with one side of the piston exposed to pressure in flowpath 62 and the other side exposed to control system pressure at a port such as 16. In those prior systems, a spring such as spring 60 was required to resist the hydrostatic pressure created in the control tubing from the surface down to a port such as 16. For applications involving significant depths, the spring rate that had to be used on such springs as 60 was significant in order to support a piston against the hydrostatic load in the control tubing. Additionally, sleeves in prior designs had to overcome production tubing pressure to be shifted down to open the SSV. The control line hydrostatic would partially offset the required opening force. As a result, in order to shift the sleeve in prior designs, significant hydraulic pressures had to be applied to the piston to overcome the resistance of the stiff spring rate of a spring required to resist the hydrostatic forces in an effort to open the SSV. This is to be contrasted with the present design where the actuation assembly involving pistons 22 and 40 are in pressure balance with respect to the production flowpath 62. As a result, spring 60 need only support the weight of sleeve 10 and, therefore, can be a spring with a significantly lower spring rate than those that would have in the past been required to service deep applications. For example, in the past a spring such as 60 on a prior design, without the pressure-balance feature of the present invention, would have required spring forces in the order of 700 lbs. when the SSV B is in the closed position, whereas use of the apparatus of the present invention, in a comparably sized valve at the same depth, can now employ a spring having a preload force of about 50 lbs. or less when the SSV B is closed. The natural outcome of the use of springs with smaller spring rates is that the actuation pressure that is applied at port 16 to initiate opening of the SSV B is reduced from prior applications where pressures in the order of 10,000-15,000 psi were required. Now, with the apparatus of the present invention, pressures on the control system at the surface can be down to a range of 1,000-3,000 psi. This allows the use of existing hydraulic control system components for surface equipment to also be used for controlling of the SSV.
Referring now to FIGS. 3 and 4, the shuttle valve V of the present invention will be described. Shuttle valve V has a housing 64 which contains a plurality of ports. The first port is represented by arrow 66. Arrow 66 indicates the connection point of the control line which is run from the surface to shuttle valve V. Shuttle valve V has a pair of output connections 68 and 70. Output connection 68, as indicated schematically by the arrow, is ultimately connected to port 16, as illustrated in FIGS. 1A and 10A. Output port 70 in FIG. 3 is schematically illustrated by virtue of the arrow to be ultimately connected to control line 50 through housing 52 (see FIG. 2). Shuttle valve V has an opening 72 which is in flow communication with the annulus outside the production tubing (not shown). Inside shuttle valve V is a piston 74. In the preferred embodiment piston 74 has one end 76 shaped essentially spherically for sealable contact against seat 78. The other end of piston 74 extends into chamber 80. End 82 on piston 74 has a cylindrical component conforming to the shape of cavity or chamber 80. Seal 84 is imbedded in a groove in end 82 effectively dividing chamber 80 into two chambers, 80 and 86. Also found in chamber 80 is a compensating spring 88 which bears on surface 90 of piston 74. Chamber 80 can be initially at atmospheric pressure or can have pressures higher than atmospheric. The higher the trapped pressure in chamber 80, the weaker the compensating spring that will need to be used for a predetermined range of expected annulus pressures.
In operation, port 72 is normally closed due to the contact of spherical end 76 with seat 78. This seating engagement is further encouraged by any pressure in chamber 86, as well as spring force applied from spring 88. The SSV B is designed to failsafe in the closed position. In order to initiate the steps to open the SSV by sliding sleeve 10 (see FIG. 1), hydraulic pressure is applied from the surface into port 66, represented by the arrow. Port 66 is in communication with chamber 86 as well as chamber 92, in the position shown in FIG. 3. This is because no seal exists between the housing 64 and piston 74 in the area between chambers 86 and 92. Since the same pressure initially applied to port 66 exits the valve V through ports 68 and 70, there is no differential pressure applied to the assembly of pistons 22 and 40 (see FIG. 1), and hence no movement of sleeve 10. However, as pressure is allowed to build up from the surface into port 66, an unbalanced force acting on piston 74 is generated. This occurs when the pressure in cavity 86 applied on annular surface 94, as well as annulus pressure applied through port 72 onto end 76, exceeds the force in the opposite direction applied by spring 88 to surface 90, as well as the pressure in chamber 80 also applied to surface 90. At that point, piston 74 begins to move in a direction where chamber 80 becomes smaller and chamber 86 becomes larger. As a result of such movement, end 76 moves away from seat 78. Port 70, represented by the arrow which, in effect, leads to conduit 48 (see FIG. 2), is now placed in alignment with open port 72, which communicates with the annulus. Accordingly, built-up pressure formerly in cavity 92, which had been applied to piston 40 through conduit 48, is now relieved to the annulus. The built-up pressure in chamber 86, which is now sealed from chamber 92 at seat 97, acts on piston 22 through ports 68 and 16. The pressure imbalance between pistons 22 and 40 causes sleeve 10 to move downward by contact between connector 34 and tab 56, compressing spring 60 and opening the SSV B.
When it is desired to close the SSV B, the pressure applied to port 66 from the surface is removed. Eventually, a force imbalance in the opposite direction occurs on piston 74 and it moves in the direction toward port 72 until end 76 once again reseats against seat 78. The removal of pressure from the surface coming to inlet 66 also reduces the pressure exiting valve V through port 68, which ultimately gets into port 16, as shown in FIG. 1A. The reduction of control pressure in port 16 allows spring 60 to shift sleeve 10 and finally to allow spring 14 to close the SSV B.
Shown in FIG. 4 is an alternative embodiment of the shuttle valve V of the present invention. In the schematic representation shown in FIG. 4, pressure in the control line is applied from the surface to ports 96 and 98, as represented schematically by the arrow shown. Port 96 is in fluid communication with chamber 100. Chamber 100 is isolated from chamber 102 by seal 104 encircling piston 106. Piston 106 further has a pair of seals 108 and 110 which straddle groove 112. Shuttle valve V further has a chamber 114 within which resides a spring 116. Chamber 114 is scaled by virtue of seal 110 and contains a compressible fluid which can be at atmospheric pressure or at some higher pressure. The spring rate required for spring 116 varies inversely with the amount of pressure trapped in chamber 114. Groove 112 is in flow communication with outlet 118, represented schematically by an arrow. Outlet 118 is in fluid communication with the annulus outside the production tubing. Chamber 102 has a pair of exit ports 120 and 122, both shown schematically by arrows. Port 120 is connected to what is shown as port 16 in FIG. 1, while port 122 is in fluid communication ultimately with line 50 through housing 52, as shown in FIG. 2.
In operation, the sequence to open the SSV B requires a build-up of control pressure from the surface into ports 96 and 98. When pressure has been built up in ports 96 and 98 to a predetermined amount, a force imbalance occurs on piston 106, which operates against the spring 116 and the compressible fluid in chamber 114. The supply pressure in the control line introduced into chamber 102 from port 98 exits the valve V and acts on pistons 22 and 40 through outlets 120 and 122, respectively. Since initially the pressure exiting valve V from outlets 120 and 122 is the same, no movement of sleeve 10 occurs. However, once the force imbalance situation is achieved on piston 106, it begins to shift to the right, making cavity 114 smaller while enlarging cavity 100. While the same pressure is always applied to inlets 96 and 98, the exposure surface to the piston 106 in chamber 102 is tapered surface 124, which has a smaller cross-sectional area than circular surface 126 on the top of piston 106. Ultimately, the pressure in chamber 100 acting on surface 126 overcomes the combined resistance to movement of piston 106 offered by the pressure in chamber 102 acting on surface 124 in combination with the spring 116 and the compressible fluid in chamber 114. As piston 106 moves to make chamber 114 smaller, seal 108 and groove 112 pass beyond opening 118. This places opening 118, which is in flow communication to the annulus, in flow communication with outlet 122, which is in flow communication with line 50 and conduit 48 going to piston 40. At the same time, seal 104 passes outlet 120. Accordingly, the pressure applied from the control line at the surface passes through chamber 100 into outlet 120 to act through opening 16 onto piston 22. The combination of a build-up of pressure on top of piston 22, together with the relief of pressure in line 50 and conduit 48, puts an unbalanced force on connector 34. In turn, connector 34 bears down on tab 56, pushing sleeve 10 down against the resistance of spring 60 to open the SSV B. As long as a sufficient force is applied in the control line from the surface to prevent return movement of piston 106, the SSV B stays open. At the same time that the task of opening the SSV B has been accomplished, a controlled volume from the control system, primarily from line 50 and conduit 48, is purged from the system into the annulus. This occurs because the annulus is at a lower pressure than line 50 and conduit 48 at the time that groove 112 and seal 108 pass beyond outlet 118. When it is desired to close the SSV B, pressure is removed from the control line from the surface, reducing the applied pressure at ports 96 and 98. A pressure imbalance on piston 106 in the direction of making chamber 100 smaller now occurs. As soon as piston 106 shifts sufficiently so that seal 104 again passes outlet 120 to the position shown in FIG. 4, the built-up pressure in outlet 120, which as previously stated is connected to port 16 and ultimately to piston 22, is now equalized with port 122. This facilitates spring 60 pushing on tab 58 to shift sleeve 10 upwardly through its connection to connector 34 and tab 56. As a result, the SSV B closes.
The schematic hydraulic circuit diagrams shown in FIGS. 5-9 indicate the various configurations of shuttle valve V illustrated in FIGS. 3 and 4 during the process steps of initial position through opening of the SSV B and again to its closing. The initial position of the shuttle valve V is illustrated in FIG. 5. The connections are labeled with the same numerals as FIG. 3 for ease of understanding. In FIG. 6, hydrostatic pressure is initially applied from the surface through port 66 and is in flow communication with ports 68 and 70. In FIG. 7, the pressure has risen to a sufficient level to shift piston 74, aligning control pressure from the surface at port 66 to port 68 only. At the same time, outlet port 70 is placed in communication with port 72 leading to the annulus. FIG. 8 is similar to FIG. 7, with the pressure from the surface into inlet 66 continuing; however, the purging flow from port 70 out to the annulus has ceased. FIG. 9 shows a removal of pressure at port 66, which allows the higher pressure at port 68 to equalize into port 70. During the steps shown in FIG. 8, to hold sleeve 10 in the position where SSV B is in the open position, the operating pressure at port 68 exceeds that at port 70, with port 70 actually reflecting annulus pressure. When piston 74 once again moves to align ports 68 and 70, the pressure equalizes, allowing pistons 22 and 40 to shift in reaction to spring 60 bearing on tab 58, thereby moving sleeve 10 upwardly, finally allowing the SSV B to close.
It should be noted that although a spring in combination with a seal chamber, such as 116 and 114, respectively, is illustrated, other types of forces can be used to act initially on a piston such as 106. The physical execution of shuttle valve V can be accomplished in different ways than those illustrated and still accomplish the objective of the present invention of actuation of the control system to operate the SSV while, at the same time, automatically purging a predetermined volume from the control circuit to avoid abnormal wear on operating parts of the control system, such as seals 26, 28, 44, and 46.
The nature of the compressible fluid used in chambers 80 or 100, as well as the spring rate in the springs mounted therein, can be altered without departing from the spirit of the invention. Different fluids, initial pressures, or spring rates can be used depending upon the dimensional relationships of the piston involved and the expected forces on the piston from annulus pressure for the depth of the desired application for the embodiment illustrated in FIG. 3.
It is clear that the embodiment of FIG. 4 is not sensitive to actual or fluctuations of the annulus pressure since piston 106 is essentially in force balance from any pressure coming into it from outlet 118 in fluid communication with the annulus. One advantage to the shuttle valve V of the present invention is that, upon initiating the steps necessary to open the SSV B, the control fluid pressure is applied directly to pistons 22 and 40. Thereafter, to get movement of those pistons, the only incremental force necessary in the control line, such as 66, is a force sufficient to create the pressure imbalance on piston 74, which is, in essence, the pressure in chamber 80 and the spring force from spring 88. Similarly, in FIG. 4, incremental pressure in the control line through ports 96 and 98 is only needed to overcome the resistance to movement of piston 106 coming from the pressure applied from the compressible fluid in chamber 114 and the spring 116. Again, this minimal incremental force needed, which in the preferred embodiment can be in the order of 1000 to 3000 psi, facilitates the use of existing hydraulic systems that control surface safety components. By keeping the pressure requirements of the system at a low level, redundant high-pressure systems for the control of the SSV are not required.
In the preferred embodiment, the shuttle valve of FIG. 4 is preferably used in applications where there will be lower differential pressures between annulus pressure and the control pressures used in chamber 102. This is because it is desirable to keep the differential pressure low when a seal such as seal 108 or 104 moves across an opening in the body of shuttle valve V. The design of FIG. 3 can be used where there are higher differential pressures between the annulus pressure and the control pressures applied through port 66 since that design does not incorporate seals moving across open ports. It is within the purview of the invention to have alternative arrangements for the sealing off, which is illustrated in FIG. 3 as occurring between end 76 and seat 78. While a metal-to-metal seat is illustrated, other types of seating are within the purview of the invention, including the use of resilient materials for the seat or at the end 76 of piston 74.
Thus the improvement shown in FIG. 1, which illustrates the force balance on the actuation assembly by exposure of connector 34 to production tubing pressure in flowpath 62, acts to reduce the required pressures of the hydraulic control system which ultimately is used to move pistons 22 and 40. Additionally, by combining that system with the shuttle valve V, minimal incremental control pressures are required to initiate the opening sequence for the SSV B. As compared to prior designs where an internal sleeve spring had to resist the hydrostatic head in the control line from the surface, the present design is insensitive to the hydrostatic head from the control line. In prior designs, the greater depth meant higher control pressures were required to overcome a stiffer spring. A stiffer spring in a pilot valve was required to hold back the hydrostatic pressure in the control line, which increased with the depth of the application. By combining the force balance feature illustrated in FIG. 1, the spring 60 can have a significantly lower spring rate than in prior designs. The combination of that feature with the shuttle valve V further reduces the pressure requirements on the control system by, in effect, using the control pressure from the surface to act on both pistons 22 and 40 in a sequential manner to accomplish the opening and subsequent closing of the SSV B.
In FIG. 12, the previously described control system is enhanced to allow for the recovery and reuse of control fluid when the control system is actuated. FIG. 12 schematically illustrates a single control line 150, which preferably comes from the surface to the shuttle valve assembly S. The control line pressure through line 150 enters a port 152 wherein in the position shown in FIG. 12 there is fluid communication to ports 154, 156 and 158, with port 160 blocked off by piston 162, which is biased by spring 164. Outward flow from chamber 166 through port 158 is blocked by check valve 168. Spring 164 is disposed in chamber 170 of shuttle valve S. Chamber 170 has an outlet 172 which is connected to line 174, which ultimately joins line 176 from check valve 168. Outlet 160 has a line 178 which is connected to it and ultimately is in fluid communication with line 174, which in turn has line 176 connected into it. Between outlet or port 160 and the connection from line 174, line 178 has a flow restrictor 180 disposed in it to create backpressure on port 160, as will be described below. After being joined by line 174, line 178 continues to an isolation valve 182, which operates normally open. Thereafter, line 178 has a branch for a fill port 184. Adjacent fill port 184 is a check valve 186 which prevents outward flow past the fill port 184, all on a branch line from line 178. The main line 178 continues into chamber 188. Chamber 188 has an inert gas pressure blanketing system schematically represented by arrow 190. The nitrogen blanketing system 190 selectively allows displaced fluid from port 160 to enter chamber 188 when it is necessary to open the subsurface safety valve, as illustrated in FIGS. 1A-C. Additionally, when the subsurface safety valve is allowed to go to a closed position by removal of or reduction of pressure in line 150, the built-up pressure in chamber 188 by the nitrogen system 190 allows accumulated fluid to be replaced into the hydraulic circuit through check valve 168. Those skilled in the art will appreciate that additional controls can be placed on chamber 188 to ensure against addition of gases into the hydraulic control circuit which could disadvantageously affect its operation. Such controls could be level sensors which trigger the nitrogen system 190 to easily admit additional fluid by regulating pressure in chamber or vessel 188 at a level lower than the predetermined pressure required to shift piston 162. When pressure is lowered in line 150, the nitrogen system 190 is automatically triggered to displace fluid accumulated in chamber 188 by maintaining a preset pressure by supplying gas to replace the displaced fluid until a low-level setting is achieved. Other ways to regulate the level in chamber 188 can be employed without departing from the spirit of the invention. Other blanketing or motive fluids other than nitrogen can be employed in the pressure system 190 without departing from the spirit of the invention. The details of the pressure- or level-regulation system which could selectively be employed are known control systems to those of skill in the art.
The function of the hydraulic system, as illustrated in FIG. 12, is similar to that previously described. Outlets 154 and 156 are, respectively, connected to an actuating cylinder 192, which has internally a piston 194, illustrated schematically. The schematic piston 194 is akin to the connected pistons 22 and 40, as illustrated in FIGS. 1A-C, and has a tab 195 to engage a sleeve (not shown) for reciprocal movement. Ultimately, when the schematic piston 194 shifts, it moves a sleeve such as sleeve 10, indicated in FIG. 1A, through the use of a tab 56, as shown in FIG. 1B. However, for clarity and simplicity in FIG. 12, the cylinder 192 and piston 194 are shown schematically without a representation of the final control element, i.e., a sleeve, such as sleeve 10 shown in FIGS. 1A-C.
In the position shown in FIG. 12, a subsurface safety valve is in the closed position since a sleeve, such as sleeve 10 shown in FIG. 10A-C, is in the up position. In order to shift a sleeve such as sleeve 10 downwardly, pressure must be built up in control line 150 to displace the pressure equilibrium between outlets 154 and 156. As previously indicated, the cylinder 192 has a piston or pistons 194 therein, schematically illustrated in FIG. 12, which are in pressure balance, independent of the depth of submergence of the assembly illustrated in FIG. 12. In order to cause a pressure imbalance on piston 194, pressure is built up in control line 150. Since the piston 162 is biased against seat 196, port 160 is effectively closed. Port 158 is effectively closed because check valve 168 permits flow only into chamber 166 but not out of chamber 166 through port 158. As pressure begins to build in chamber 166, the force of spring 164 is overcome and the piston 162 lifts off the seat 196. At that point, flow begins through outlet 160 through restrictor 180 on the way ultimately to the chamber 188. The initial pressure in chamber 188 is lower than the operating pressure at that time in cavity 166; hence, the differential pressure across the restrictor 180 causes a flow therethrough. Because of the restriction in flow restrictor 180, a backpressure is created which limits the amount of flow into chamber 188 as the piston 162 is stroking against the force in the opposite direction provided by spring 164. Movement of the piston 162 in compressing spring 164 reduces the volume of cavity 170 and displaces fluid out of cavity 170 through port 172 and into line 174. As can be seen from FIG. 12, line 174 bypasses the flow restrictor 180. This means that the chamber 170 is connected to a lower-pressure zone at line 178 than is outlet 160, which must go through the flow restrictor 180 before reaching line 178 where line 174 ties into it. Ultimately, the piston 162 moves sufficiently to the left to compress spring 164 while such movement causes flow through restrictor 180. When movement of piston 162 results in contact of taper 198 with shoulder 200, there is a pressure differential between ports 154 and 156 . In effect, the restriction 180 serves to limit the volume of flow into chamber 188, as piston 194 is moved due to the differential pressure which is created between ports 154 and 156 as a result of the shifting of piston 162 until taper 198 bottoms on shoulder 200. The differential occurs because port 154 is pressurized, while port 156 only sees a lower pressure due first to the backpressure during flow through restrictor 180. Downstream of restrictor 180 in chamber 188, the control pressure maintained by the system 190 is always less than the pressure in line 150 required to move piston 162 against spring 164. This differential induces flow into chamber 188. Movement of piston 162 does result in some fluid displacement out of chamber 170 through port 172 and ultimately toward chamber 188 through line 174. When sufficient differential exists between ports 154 and 156, movement of piston 194 occurs and ultimately the final control element, i.e., a sleeve such as sleeve 10, is shifted downwardly to open the subsurface safety valve as previously described.
The fill port 184 is used for initial filling of the lines. A vent can be part of the control system 190 to release gas for pressure control or even to release hydraulic fluid in the event of a system 190 upset or malfunction. The isolation valve 182 is used if maintenance is required on the control circuits illustrated in FIG. 12.
In order to allow the subsurface safety valve to close as a result of an upward shifting of a sleeve such as 10, the pressure is merely reduced in the control line 150 until the force exerted by spring 164 overcomes the opposing hydraulic force and the piston 162 shifts to the right, bringing piston 162 back up against seat 196 and returning it to the position shown in FIG. 12. When the pressure in the control line 150 is reduced, taper 198 comes away from shoulder 200, which has the effect of pressure-equalization between ports 154 and 156, as previously described. With the reduction of applied pressure in the control line 150, the nitrogen pressurization system 190 acts to displace any accumulated fluid in chamber 188 back into the circuit through check valve 168 through a parallel line that bypasses restrictor 180.
The additional features illustrated in FIG. 12 allow for collection and recycling of the hydraulic control fluid as opposed to purging it as illustrated in the embodiment relating to FIGS. 1-10. This not only results in a costs savings to the operator in control fluid, but it also reduces the potential for pollution since stroking of piston 162 results in collection of any displaced fluid from the control circuit and an automatic return of any accumulated fluid back into the circuit. As previously described, a level controller, shown schematically as LC, can be connected pneumatically, hydraulically, or electrically to the nitrogen system 190, as indicated by dashed line 202, to use the applied pressure from the nitrogen blanketing system 190 to control the level in chamber 188. Upon rising level, the control system 190 can automatically vent gas in a manner well-known in the art.
The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made without departing from the spirit of the invention.
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The invention relates to a control system for a subsurface safety valve (SSV). A pressure-balance feature is introduced such that the control system components are unaffected by the depth of placement of the SSV. Through the use of this feature, the standard hydraulic control system used for surface components can also be used for an SSV regardless of its depth of installation. In another feature of the invention, a shuttle valve is provided so that each time the SSV is stroked, a volume of control fluid is purged into the annulus. One embodiment of the shuttle valve may or may not be sensitive to annulus pressure and employs annulus pressure as an aid to stroking the shuttle valve upon application of surface control pressure to assist in actuation of the SSV, while at the same time providing for a purge of a controlled volume of fluid.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of and claims priority to U.S. patent application Ser. No. 12/709,897, now, U.S. Pat. No. 8,110,355, entitled “Method for Identifying Agents that Inhibit Cell Migration, Promote Cell Adhesion and Prevent Metastasis,” filed Feb. 22, 2010, which claims priority to provisional U.S. Patent Application filed Feb. 20, 2009, having a Ser. No. 61/154,251, the disclosures of which are hereby incorporated by reference in their entireties.
FIELD OF THE INVENTION
The invention relates to an assay that can identify agents that inhibit cell migration, promote cell adhesion and prevent metastasis.
BACKGROUND OF THE INVENTION
Metastasis of cells from a primary tumor in mammals leads to the spread of cancer to other tissues of the body (1-3). The spread of metastases may occur via the blood or the lymphatics or through both routes. Cancer cell metastasis commonly occur in lungs, liver, brain, and the bones. These secondary aggressive cancers lead to organ dysfunction and ultimately death (Metastatic Cancer: Questions and Answers”. National Cancer Institute). To date, there are few effective treatments for metastatic cancers.
Signaling pathways that promote cell detachment and/or metastasis are largely unknown. However, we have discovered signaling pathways that unexpectedly regulate cell adhesion to the extra-cellular matrix (ECM) are prime candidates for promoting metastasis (4). These pathways may be impacted upon by the many genetic and epigenetic changes as a cell transitions to malignancy, together with microenvironmerital changes such as changes in hormone signaling.
Wound dehiscence is the premature “bursting” open of a wound along surgical suture. It is a surgical complication that results from poor wound healing. Risk factors are age, diabetes, obesity, poor knotting/grabbing of stitches and trauma to the wound after surgery. Agents that promote cell adhesion could speed healing. Retinal detachment is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized, but without rapid treatment the entire retina may detach, leading to vision loss and blindness. Agents that promote cell adhesion could speed healing. Aortic dissection is a tear in the wall of the aorta that causes blood to flow between the layers of the wall of the aorta and force the layers apart. Aortic dissection is a medical emergency and can quickly lead to death, even with optimal treatment. If the dissection tears the aorta completely open (through all three layers), massive and rapid blood loss occurs. Agents that promote cell adhesion could speed heating. Major skin trauma (e.g. burns, amputation) can be treated with temporary, artificial or autologous skin replacement. Agents that promote cell adhesion could speed healing. Blastocyst attachment to the endometrium of the uterine wall is essential for pregnancy and is a cause of infertility, Agents that promote blastocyst attachment could prevent infertility. Unfortunately, signaling pathways that regulate cell adhesion are largely unknown.
We have identified a pathway, the activin receptor type II (ActRII) signaling pathway, that regulates cell adhesion, Blocking ActRII signaling alters cellular morphology and increases cell detachment. Cell detachment correlates with an increase in the expression of ADAM-15, disintegrin which cleaves integrin molecules (5) and cadherin (6), in this context, it has recently been demonstrated that the expression of ADAM-15 is strongly correlated with the metastatic potential of prostate, breast (7) and pancreatic cancers (8) and is highly up-regulated in aggressive prostate cancer (6). Furthermore, ADAM-15 has been shown to be involved in cell migration and invasion (9, 10). Signal transduction components of the activin signaling pathway are highly down-regulated in prostate cancer (11, 12). In vitro, inhibition of ADAM15 expression in PC-3 cells decreases cell migration and adhesion to specific extracellular matrix proteins, and is accompanied by a reduction in the cleavage of N-cadherin by ADAM15 at the cell surface (6). In patients with hone metastasis from prostate cancer, circulating levels of activin A are significantly higher (13). These findings indicate that ActRII mediates cell adhesion (and viability) via the regulation of ADAM-15 expression and function.
Modulation of ActRII signaling and associated disintegrins can be used to identify drugs that enhance ActRII signaling and promote cell attachment, or inhibit the expression and/or function of disintegrins associated with promoting cell detachment. Accordingly, it is desirable to provide a method, kit, and apparatus for utilizing ActRII signaling and associated disintegrins to identify compounds and conditions capable of modulating adhesion characteristics of cell.
SUMMARY OF THE INVENTION
The foregoing needs are met, to a great extent, by the present invention, wherein in one respect methods and kits for identifying agents that inhibit cell detachment and increase cell attachment, and to the use of such agents to develop methods of preventing, treating or alleviating and/or the symptoms of cancer, and other diseases and conditions is provided. Some examples of such diseases and conditions are described. More specifically, the present invention is directed to the identification of agents that could be used to treat cancer, or other conditions and diseases where cell detachment or migration is detrimental, or where cell adhesion is beneficial. The methods may include detecting, either directly or indirectly, agents that increase ActRII signaling, and/or decrease disintegrin or metalloprotcase expression and/dr function, and prevent cell detachment and cell invasion. Conversely, methods may include detecting, either directly or indirectly, agents that decrease ActRII signaling, and/or increase disintegrin or metalloprotease expression and/or function, and increase cell attachment and cell invasion.
An embodiment of the present invention pertains to a method of identifying an agent to modify cell adhesion. In this method, cells from an animal are adhered to a matrix, cell detachment from a matrix is induced by suppressing ActRII signaling, the agent is introduced, and a change in cell detachment as a result of introducing the agent is measured.
Another embodiment of the present invention relates to a kit to identify an agent to modify cell adhesion. The kit includes a cell growth media, a container having a surface matrix for cell adhesion, and a cell detachment solution having a concentration of an ActRII signaling suppressor sufficient to induce cell detachment.
Yet another embodiment of the present invention pertains to a composition to induce cell detachment comprising a concentration of an ActRII signaling suppressor sufficient to induce cell detachment.
There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates the ActRII signaling pathway linked to the expression and function of the disintegrin ADAM15.
FIG. 2 illustrates that ActRII blocking antibody suppression of ActRII signaling promotes morphological changes, increased detachment and decreased viability of prostate cancer cells.
FIG. 3 illustrates that anti-ActRII oligonucleotide (antisense P) suppression of ActRII signaling promotes increased ADAM15 expression, increased detachment and decreased viability of prostate cancer cells.
FIG. 4 illustrates that suppressing ActRII signaling promotes morphological changes, increased detachment and decreased viability of prostate cancer cells.
FIG. 5 illustrates antisense oligonucleotide suppression of ActRII along with ADAM 15 suppression to prevent cell detachment.
DEFINITIONS
The present invention is described herein using several definitions, as set forth below and throughout the application.
As used in this specification and the claims, the singular forms “a,” “an,” and “the” include plural forms unless the content clearly dictates otherwise.
As used herein, “about”, “approximately,” “substantially,” and “significantly” will be understood by persons of ordinary skill in the art and will vary to some extent on the context in which they are used. If there are uses of the term which are not clear to persons of ordinary skill in the art given the context in which it is used, “about” and “approximately” will mean up to plus or minus 10% of the particular term and “substantially” and “significantly” will mean more than plus or minus 10% of the particular term.
As used herein, the term “including” has the same meaning as the term “comprising.”
As used herein, the term “cancer cell line” or “cancer cells” may be used interchangeably and refers to cells isolated from a tumor, metastasis or abnormal growth derived from an animal or human. These cells typically, but not always, grow rapidly in culture when supplemented with appropriate growth factors, often fetal animal serum. This term also refers to normal cells transformed into cells that display typical features of cancer cells, i.e. they divide in cell culture under trophic support and/or form tumors when administered to animals.
Cancer cell lines may include, but are not limited to, human prostate cancer cells (PC-3, LNCaP, DU-145), human mammary epithelial cells (e.g. MCF-7, MCF-10A, MDA-MB-438, MDA-231, MDA-468, T47D, SkBr3), human neuronal cells (M17, SHSYSY, H4, U87), human acute myeloid leukemia cells (THP-1), human bone cancer cells (Saos-2 cells), human melanoma cells (721), human glioblastoma cells (A172), human head and neck carcinoma cells (A253), human skin epithelial cells (A431), human lung carcinoma epithelial cells (A-549), human peripheral blood mononuclear cell lymphoma (BCP-1), human pancreatic adenocarcinoma cells (BxPC3), human squamous cell carcinoma (Cal-27), human CML acute phase T cell leukemia cells (CML T1), human CML blast crisis Ph+ CML cells (EM2), human CML blast crisis Ph+ CML cells (EM3), human metastatic lymph node melanoma cells (FM3), human lung cancer cells (H1299), human hybridoma cells (HB54), human fibroblasts (HCA2), human kidney embryonic epithelial cell (HEK-293), human cervical cancer epithelial cell (HeLa), human myeloblast blood cells (HL-60), human mammary epithelial cells (HMEC), human colon epithelial adenocareinoma cells (HT-29), human umbilical cord vein endothelial cells (HUVEC), human T-cell-leukemia white blood cells (Jurkat), human lymphoblastoid EBV immortalized B cells (JY cells), human lymphoblastoid CML blast crisis cells (K562 cells), human lymphoblastoid erythroleukemia cells (Ku812), human lymphoblastoid CML cells (KCL22), human lymphoblastoid AML cells (KG1), human lymphoblastoid CML cells (KY01), human melanoma cells (Ma-Mel 1, 2, 3 through 48), human WBC myeloid metaplasia AML cells (MONO-MAC 6), human T cell leukemia (Peer), human osteosarcoma cells (Saos-2), human T cell leukemia/B cell line hybridoma (T2), human colorectal carcinoma/lung metastasis epithelium cells (T84), human colorectal adenocarcinoma cells (HCT-15, HT-29), human monocyte AML cells (THP1), human glioblastoma-astrocytoma epithelial cells (U373), human glioblastoma-astrocytoma epithelial-like cells (U87), human leukemic monocytic lymphoma cells (U937), human lymphoblastoid cells (WT-49), human B-cell EBV transformed cells (YAR), human breast adenocarcinoma cells (NCl/ADR-RES. MDA-MB-231), human CNS glioblastoma cells (SF-268), human ovary adenocarcinoma cells (SK-OV-3), human lung carcinoma cells (NCIH460), human lung adenocarcinoma cells (A549), human liver carcinoma cells (Hep3B), human uterine sarcoma-drug sensitive cells (MES-SA), human uterine sarcoma—drug resistant cells (MES-SA/DX5), human skin primary melanoma cells (WM39), ape-kidney fibroblast cells (COS-7), African green monkey kidney epithelial cells (Vero cells), murine brain/cerebral cortex endothelial cells (bEnd.3), murine embryonic mesenchymal cells (C3H-10T1/2), murine T cell leukemia ECACC cells (EL4), marine embryonic fibroblasts (NIH-3T3), murine embryonic calvarial cells (MC3T3), murine hepatoma epithelial cell (Hepal cic7), marine adenocarcinoma cells (MC-38), murine epithelial cells (MTD-1A), murine endothelial cells (MyEnd), murine renal carcinoma cells (RenCa), murine melanoma cells (X63), murine lymphoma cells (YAC-1), murine T cell tumor cells (RMA/RMAS), murine breast adenocarcinoma cells (4T1), murine mammary normal epithelial cells (NmuMG), rat glioblastoma cells (9L), rat neuroblastoma cells (B35), canine mammary tumor cells (CMT), canine osteosarcoma cells (D17), canine histiocytosismonocyte/macrophages (DH82), rat pheochromocytoma cells (PC-12), rat pituitary tumor (GH3), canine kidney epithelial cells (MDCK II), murine B lymphoma B cells (lymphocyte A20), murine hone marrow stromal cells (ALC), murine melanoma cells (B16), murine colorectal carcinoma cells (CT26), baby hamster kidney fibroblasts (BHK-21), Asian tiger mosquito larval tissue (C6/36), insect-ovary cells (Sf-9), Chinese hamster ovary cells (CHO), onyvax prostate cancer cells (OPCN, OPCT), tobacco cells (BY-2), zebratish cells (ZF4 and AB9), Madin-Darby Canine Kidney (MDCK) epithelial cells, Xenopus kidney epithelial cells (A6).
As used herein, the term “primary cells” refers to cells isolated from tissues of animals.
Primary cells include, but are not limited to, keratinizing epithelial cells, wet stratified barrier epithelial cells, exocrine secretory epithelial cells, holinone secreting cells, metabolism and storage cells, barrier function cells of lung, gut, exocrine glands and urogenital tract, kidney cells, epithelial cells lining closed internal body cavities, ciliated cells, extracellular matrix secretion cells, blood and immune system cells, cells of the nervous system, autonomic neuron cells, sense organ and peripheral neuron supporting cells, central nervous system neurons and glial cells, lens cells, pigment cells, germ cells, nurse cells, interstitial cells, stem cells and other cells (see Appendix 1 for list of cells).
A “cell array” refers to a substrate comprising a plurality of cancer or primary cell lines.
The present methods and kits may utilize cell arrays to test agents for cell adhesion, cell invasion and cell viability.
The term “oligonucleotide” or “siRNA” refers to a nucleic acid sequence or fragments or portions thereof, which may be single or double stranded, and represents the sense or antisense strand. A oligonucleotide may include DNA or RNA, and may be of natural or synthetic origin. For example, a oligonucleotide or siRNA may include cDNA or in RNA. Oligonucleotides may include nucleic acid that has been amplified (e.g., using polymerase chain reaction). The oligonucleotide may contain phosphorothicate bonds.
The term “oligonucleotide” is understood to be a molecule that has a sequence of bases on a backbone comprised mainly of identical monomer units at defined intervals. The bases are arranged on the backbone in such a way that they can enter into a bond with a nucleic acid having a sequence of bases that are complementary to the bases of the oligonucleotide. The most common oligonucleotides have a backbone of sugar phosphate units. Oligonucleotides of the method which function as antisense oligonucleotides are generally at least about 10-15 nucleotides long and more preferably at least about 15 to 25 nucleotides long, although shorter or longer oligonucleotides may be used in the method. The exact size will depend on many factors, which in turn depend on the ultimate function or use of the oligonucleotide. An oligonucleotide antisense sequence) that is specific for a target nucleic acid will “hybridize” to the target nucleic acid under suitable conditions. As used herein, “hybridization” or “hybridizing” refers to the process by which an oligonucleotide single strand anneals with a complementary strand through base pairing under defined hybridization conditions. Oligonucleotides used as antisense oligonucleotides for specifically inactivating gene transcription or translation are capable of specifically hybridizing to the target gene.
The present methods and kits may utilize oligonucleotides. The term “antisense” and “sense” are complimentary to “antisensc oligonucleotide” and “sense oligonucleotide”, respectively, and refers to an oligonucleotide that hybridizes to a target nucleic acid and is capable of specifically hybridizing to the target nucleic acid. Antisense or sense may be fully complementary to a target nucleic acid sequence or partially complementary. The level of complementarity will depend on many factors based, in general, on the function of the antisense or sense oligonucleotide. An antisense oligonucleotide can be used, for example to prevent gene transcription and translation for the formation of proteins. A sense oligonucleotide does not prevent gene transcription and translation for the foil-nation of proteins. Antisense and sense oligonucleotides can be labeled or unlabeled, or modified in any of a number of ways well known in the art. An antisense and sense oligonucleotides may specifically hybridize to a target nucleic acid.
As used herein, a “target nucleic acid” refers to a nucleic acid molecule containing a sequence that has at least partial complementarity with a target DNA/RNA sequence. A target DNA/RNA may specifically hybridize to a target nucleic acid.
As used herein, an “inhibitor” refers to a molecule that blocks or decreases the function, phosphorylation or translocation of a protein or the binding of a protein to another.
An “amino acid sequence” refers to a polypeptide or protein sequence.
The term “blocking antibody” refers to an antibody that blocks normal signaling by that protein, usually by binding to a particular amino acid sequence of that protein.
As used herein, the term “agent,” which may be used interchangeably with the terms “chemical”, “inhibitor” or “drug,” refers to any compound that can be applied to cells.
As used herein, the term “chemical library” means a group of distinct drugs and drug classes maintained as a group that are tested individually or in combination for their ability to affect a cellular change, e.g. cell adhesion.
As used herein, the term “assay” or “assaying” means qualitative or quantitative analysis or testing.
As used herein, the term “cell viability” refers to whether a cell is living or dead. Cell viability measurements may be used to evaluate the death or life of cells. Cell viability tests can be used to determine the effectiveness of agents to promote life, or induce death.
As used herein, the term “cell invasion” and “migrate” refers to the ability of a cell to move from its starting position to a new place, under the influence of chemotaxis agents or not.
As used herein, the term “cell attachment” and “cell adhesion” refers to cell binding to a substrate, including but not limited to plastic and other substrates referred to in and the like.
As used herein, the term “ADAM-15 expression and function” refers to the concentration of ADAM-15 protein, and the activity of that protein to act as a metalloproteinase to cleave ECM proteins. More particularly, the term ADAM-15 refers to a disintegrin and metalloproteinase domain-containing protein 15.
As used herein, the term “ActRI, Smad-2 and Smad-4 expression and phosphorylation” refers to the concentrations of ActRI, Smad-2 and Smad-4, and whether ActRI, Smad-2 and Smad-4 are phosphorylated.
As used herein, the term “ActRII binding to ALKs” refers to the binding of one member of the ActRII family of proteins to another member of the ALK family of proteins.
As used herein, the term “Smad-2:Smad-4 coupling” refers to the binding of Smad2 to Smad-4 as a complex.
DETAILED DESCRIPTION
In some embodiments, the methods include: (a) using cancer cell lines and primary cells; (b) attaching cells to a matrix; (c) inducing detachment of cancer cells or primary cells by blocking the ActRII signaling pathway using oligonucleotides, oligonucleotides with phosphorothioate bonds (antisense-P phospho-oligonucleotides), siRNA, blocking antibodies, or inhibitors of protein function, binding or translocation; (d) using agents from chemical libraries or other agents; (e) measuring cell attachment; (f) measuring cell invasion; (g) measuring cell viability; (h) measuring the expression and activity of disintegrins, (i) measuring ActRII, activin receptor-like kinases (ALKs) 1-7, Smad-2, Smad-3 and Smad-4 expression and their phosphorylation; measuring ActRII binding to ALKs; (k) measuring Smad-2:Smad-4 coupling and translocation to the nucleus. In one method, cancer cell lines are induced to detach from a culture or microwell plate and agents are tested to determine their ability to prevent detachment and cell invasion.
In a preferred embodiment, the determination of the ability of the agent to inhibit cell detachment is made by treating cultured cancer cells with antisense-P phosphooligonucleotides and then treating the cells with chemical agents and measuring cell detachment, invasion, morphology and viability.
In some embodiments, the methods may include using plastic culture plates, or plastic culture plates that are coated with different binding substrates, including but not limited to fibronectin, vitronectin, bovine serum albumin, gelatin, Matrigel, fibrous matrix proteins (such as collagen I, collagen IV), fibrinogen, non-collagenous components (such as laminin molecules; GTFALRGDNGDNGQ (SEQ ID NO 7)—portion of the laminin alpha-chain), proteoglycans (such as chondroitin sulfate, dermatan sulfate, heparin, heparan sulfate and keratan sulfate, syndecans, perlecan), non-sulfated glycosaminoglycan (such as hyaluronan), entactin, core proteins (such as lumican, keratocan, mimecan, fibromodulin, PRELP, osteoadherin and aggrecan), dystroglycan glycoprotein complex and Lutheran blood group glycoprotein. Plates may consist of one or more wells (e.g. 6-, 12-, 24-, 48-, 96-, 384-well) for high throughput screening of agents.
In some embodiments, the methods may include using any cancer cell line that can adhere to the surface of the plate.
In some embodiments, the methods may include using any primary cells from animals, or human cells from biopsies, that can adhere to the surface of the plate.
In some embodiments, the methods may include using, but are not limited to oligonucleotides, oligonucleotides with phosphorothioate bonds, RNA interference (RNA i) or inhibitors for decreasing the expression or function of the activin signaling pathway including ActRIIA and B, activin receptor-like kinases (ALKs 1-7), Smad-2, Smad-3, Smad-4, activins (A, B, C, D and E). In another embodiment, the methods may include using blocking antibodies against members of the activin signaling pathway including ActR11, ActRI, Smad-2, Smad-4, activins (A, B, C, D and B), for decreasing protein function. In another embodiment, the methods may include using oligonucleotides, oligonucleotides with phosphorothioate bonds, RNAi or inhibitors to decrease phosphorylation of activin signaling pathway members. In another embodiment, the methods may include using oligonucleotides, oligonucleotides with phosphorothioate bonds, RNAi or inhibitors to inhibit ActRIIA and/or ActRIIB binding to ALKs 1-7. In another embodiment, the methods may include using oligonucleotides, oligonucleotides with phosphorothioate bonds, RNAi or inhibitors to decrease Smad-2:Smad-4 translocation to the nucleus. In another embodiment, the methods may include natural cellular inhibitors of the signal transduction pathway of ActRII signaling such as inhibin and follistatin.
The treatments may include single agents, combinations of agents or no agents. The treatments also may include solutions used to dissolve the agents.
Cell detachment and adhesion may be detected by any suitable method, which may include, but are not limited to, cell cytometry (e.g. trypan blue), fluorescent based cell detection assays (e.g. Calcein AM (InVitrogen, Inc.), and Mitotracker Red (InVitrogen, Inc.), luminescent based detection assays (e.g. Cell-Titer glo (Promega, Inc.) and spectrophotometry based detection assays (e.g. crystal violet, MTS/MTT assays such as Promega CellTiter 96® AQueous Non-Radioactive Cell Proliferation Assay, Promega, Inc. and Chemicon Cell Adhesion Assays).
Cell invasion may be detected by any suitable method, which may include, but are not limited to, the scratch wound assay, cell invasion assays using fluorescent detection of cell invasion (e.g. activin, serum) (BD BioCoat matrigel invasion chambers, Fisher Scientific; EMD, Calbiochem; Chemicon international) with or without the use of a chemotaxic agent.
Cell viability may be detected by any suitable method, which may include, but are not limited to, cell cytometry (e.g. trypan blue), fluorescent based cell detection assays (e.g. calcein AM (InVitrogen, Inc.), and Mitotracker Red (InVitrogen, Inc.)), luminescent based detection assays (e.g. Cell-Titer glo (Promega, Inc)) and spectrophotometry based detection assays (e.g. crystal violet, MTS/MTT assays such as Promega CellTiter 960 AQueous Non-Radioactive Cell Proliferation Assay, Promega, Inc.)
Cell morphology may be assessed by capturing images using a microscope and analyzing morphological changes using software such as MetaMorph (Molecular Devices).
The disclosed methods will determine which agents or combination of agents prevent cell detachment, prevent cell invasion, promote cell attachment, promote cell invasion, increase viability, decrease viability and alter morphology.
The disclosed methods may be utilized to identify agents that: 1) prevent metastasis or the other conditions/diseases such as those described; 2) detach cells from a matrix; and 3) promote cell adhesion to a matrix. In addition, the disclosed methods may be utilized to study cell surface markers during cell detachment and how agents affect the expression and activity of those markers. Also contemplated are kits for performing the disclosed methods. A kit may include, one or more reagents for determining, either directly or indirectly, whether an agent(s) can prevent cell detachment, prevent cell invasion, promote cell attachment, promote cell invasion and alter morphology/viability.
The present methods may be performed to induce cell detachment from a matrix and to identify agents that prevent cell detachment. Cells are cultured to attain 80% confluence as known in the art. Typically cells are cultured under sterile conditions at 37° C., 5% CO2, in media supplemented with 1% penicillin-streptomycin, 2 mM glutamine, 0.4 mM sodium bicarbonate and 1-10% fetal bovine serum as determined by the cell type and as known in the art. Cells are then treated with antisense oligonucleotides with phosphorothioate bonds or RNAi to a final concentration of 0.1-10 μM. Oligonucleotides can be added directly, or added to media that has been preincubated with lipofectamine (4 ng/ml; InVitrogen Corporation, Carlsbad, Calif.) for 5 min. at room temperature, and this mixture then incubated at room temperature for 20 min. prior to addition to cells, Cell attachment, invasion and viability are significantly altered by suppressing ActRII signaling via these treatments. Agent(s) are then added to cells at concentrations ranging from picomolar to millimolar concentrations. Fluids that the agent(s) are dissolved in are added to separate wells at the same concentration. Other control wells contain no agent(s). After 0-5 days of treatment, cell attachment, invasion, morphology and viability are measured as described.
The ability of agents to prevent cell detachment is measured by the difference in cell attachment between those cells treated with and without agents. Alternatively, the percentage change in cell attachment by an agent can be measured by the level of cell attachment in the presence of the agent and oligonucleotides or blocking antibody divided by the difference between cells treated with and without oligonucleotides/or antibody alone as known in the art.
Cell detachment can be induced by, but is not limited to, the following oligonucleotides:
ActRIIA antisense-P:
SEQ ID NO 1
5′-TCCAGTTCAGAGTCCCATTTC-3′
ActRIIA sense:
SEQ ID NO 2
5′-GAAATGGGACTCTGAACTGGA-3′
ActRIIB antisense-P:
SEQ ID NO 3
5′-TCTCCCGTTCACTCTGCCAC-3′
ActRIIB sense:
SEQ ID NO 4
5′-GTGGCAGAGTGAACGGGAGA-3′
ADAM-15 Antisense-P:
SEQ ID NO 5
5′-CGCACTCTTCCCTGGTAGCA-3′
ADAM-15 Sense:
SEQ ID NO 6
5′-TGCTACCAGGGAAGAGTGCG-3′
Cell detachment can be induced by, but is not limited to, the following antibodies and inhibitors: Anti-human ActRIIB affinity-purified mouse monoclonal antibody (A0856; US Biological, Swampscott, Mass.); Anti-human mouse activin antibody (US Biologicals, MA): SB 431542 (GlaxoSmithKline). Any oligonucleotide or antibody that decreases signaling via the ActRII signaling pathway can be used to induce cell detachment.
The present methods may be performed to identify agents that promote cell attachment and prevent cell detachment from a matrix. Cells cultured as described at 50% confluence are treated with and without agents and after 0-5 days cell attachment, invasion and viability are measured in any suitable manner. Specific examples of suitable methods of measuring cell attachment, invasion and viability include thus methods described.
The present methods may be used for identifying agents that prevent cell detachment and promote cell adhesion. These agents may be used to treat any suitable metastasis and other diseases and conditions. Specific examples of suitable metastasis and other diseases and conditions include those described.
In a particular embodiment of the invention, a kit for identifying agent that prevent ActRII-mediated cell detachment is provided. The kit may include any suitable reagents for performing various assays capable of identifying agent that prevent ActRII-mediated cell detachment. In a particular example, the kit includes:
1) sense and antisense-P oligonucleotides to ActRII 2) lipofectamine 3) 96-well plate (coated with a particular matrix for different cell types). Plate would be either visible, fluorescent of luminescent light compatible. Celts would be dependent upon each researchers requirements as would the media that they would put the lipofectamine/oligonucleotides into for treatment of cells. 4) PBS buffer (for washing wells) 5) cell detection reagents
In addition, depending upon the cell number detection method, the kit may include various additional reagents for performing particular assays such as, for example, fluorescent detection of cell number, luminescent detection of cell number, spectrophotometric detection of cell number, and the like. For fluorescent detection of cell number, the kit may include reagents for calcein AM (e.g., fluorescent compatible 96-well plate). For luminescent detection of cell number, the kit may include reagents for CellTiter-Glo® (e.g., luminescent compatible 96-well plate). For spectrophotometric detection of cell number, the kit may include reagents for crystal violet assay such as:
1) PBS buffer (for washing wells) 2) crystal violet solution (0.5%; staining cells) 3) 33% (v/v) acetic acid (digesting cells) 4) (visible light compatible 96-well plate)
To perform the spectrophotometric detection of cell number: Media is removed from cells cultured in 96-well plates, the cells washed with D-PBS (Gibco, Carlsbad, Calif., USA), and 504, of crystal violet added to each well at room temperature for 10 min. Following this, 200 uL of 33% (v/v) acetic acid is added to the wells, the plate shaken for 2 min. and then read at 570 nm on a plate reading spectrophotometer.
Methods and Results
EXAMPLE 1
ActRII Oligonucleotide-induced Detachment of Cancer Cells in a Microwell Format for the High Throughput Screening of Small Molecules to Inhibit Cell Detachment
Prostate cancer cell lines (e.g. PC-3 cells) are cultured in 96-well opaque plates (luminescence compatible) at 37° C. in 100 μL of F-12 Nutrient Mixture (Ham; Gibco, InVitrogen Corporation, Carlsbad, Calif.) supplemented with 1% penicillin-streptomycin (P/S; Gibco, InVitrogen), 2 mM glutamine (InVitrogen), 0.4 mM sodium bicarbonate (Sigma, St. Louis, Mo.), and 5% fetal bovine serum (FBS, #26400-036; Gibco, InVitrogen). When cells reach 80% confluence (at least 24 h after plating to allow suitable attachment), cells are treated every day for 1-3 days with:
1) medium+0.4 μM ActRIIB sense-P oligonucleotide (SEQ ID NO 4); or 2) medium+0.4 μM ActRIIB antisense-P oligonucleotide (SEQ ID NO 3); or 3) medium+0.4 μM ActRIIB antisense-P oligonucleotide (SEQ ID NO 3)+small molecule (0-10 μM). 4) medium+0.4 μM ActRIIB sense-P oligonucleotide (SEQ ID NO 4)+small molecule (0-10 μM).
The oligomers with phosphorothioate bonds (sense and antisense-P; integrated DNA Technology, Coralville, Iowa) are added to media that has been preincubated with lipofectamine (4 ng/μl; InVitrogen Corporation, Carlsbad, Calif.) for 5 min. at room temperature. This mixture is incubated at room temperature for 20 min. prior to addition to cells. Replicates=3-6. As a modification to the above protocol, antisense oligonucleotides can be replaced with a specific binding antibody to ActRII such as anti-human ActRIIB affinity-purified mouse monoclonal antibody (A0856; US Biological, Swampscott, Mass.).
The number of viable cells attached to the plate is determined using the CellTiter-Glo® Luminescent Cell Viability Assay (Promega). Briefly, the CellTiter-Glo® Reagent is added directly to the wells of the plate (100 μL per well for 96-well plates) and the plate mixed on an orbital shaker for 2 min. Following this, the plate is incubated at room temperature for 10 min. and the luminescence recorded (typical integration time of 0.25-1 second per well) on a plate-reading luminometer. Note: Control wells are prepared containing medium without cells to obtain a value for background luminescence, and is subtracted from the values obtained for cells treated in 1, 2 and 3 above.
The % of cell detachment rescued by the small molecules is determined as the luminescence of (3-2)/(1-2) x100.
Example 2
Antisense Oligonucleotide Suppression of ActRII along with ADAM-15 Suppression Prevents Cell Detachment
To test that cell detachment induced by suppressing ActRII signaling was mediated via the metalloprotease ADAM-15, we treated PC-3 prostatic cancer cells with antisense-P against ActRII and then treated these cells with antisense-P against ADAM-15. A significant decrease in cell attachment was detected after 3 days of treatment with antisense-P against ActRII, and this was reversed by treatment with antisense-P against ADAM-15 (p<0.01, n 5). As shown in FIG. 5 , neither sense against ActRII nor together with sense against. ADAM-15 altered cell attachment. These results illustrate that cell detachment induced by suppressing ActRII signaling is mediated via the metalloprotease ADAM-15, and further indicate that antisense-P against ADAM-15 as a chemical that can prevent prostate cancer cell detachment.
Androgen-insensitive PC3 cells derived from a grade IV human prostate adenocarcinoma of epithelial origin (examples described herein) were maintained at 37° C. in F-12 Nutrient Mixture (Ham; Gibco, InVitrogen Corporation, Carlsbad, Calif.) supplemented with 1% penicillin-streptomycin (P/S; (Gibco, InVitrogen), 2 mM glutamine (InVitrogen), 0.4 mM sodium bicarbonate (Sigma, St. Louis, Mo.), and 5% fetal bovine serum (FBS, #26400-036; Gibco, InVitrogen). For the experiment, PC-3 cells were plated in 6 well plates with 10% serum at 2×10 5 cells/well for 24 h, after which cells treated every day for 3 days with:
1) media containing 10% serum+lipofectamine+sense-P oligonucleotide to ActRIIB (sActRIIB) (SEQ ID NO 4); 2) media containing 10% serum+lipofectamine+antisense-P oligonucleotide to ActRBB (aActRIIB) (SEQ ID NO 3); 3) media containing 10% serum+lipofectamine+sense-P oligonucleotide to ActRIIB (sActRIIB) (SEQ ID NO 4)+sense-P oligonucleotides to ADAM-15 (SEQ ID NO 6) 4) media containing 10% serum+lipofectamine+aActRIIB (SEQ ID NO 3)+antisense-P oligonucleotides to ADAM-15 (SEQ ID NO 5).
The oligomers with phosphorothioate bonds (Sense and antisense-P; Integrated DNA Technology, Coralville, Iowa) were added to media (240 μl) that had been preincubated with lipofectamine (4 ng/μl; InVitrogen Corporation, Carlsbad, Calif.) for 5 min, at room temperature. This mixture was then incubated at room temperature for 20 min. prior to addition to cells. Antisense-P was used at a final concentration of 0.4 μM. The number of viable PC-3 cells attached to the plate was measured after trypsinization followed by cell counting using the trypan blue staining assay at the end of 72 h. Results are presented as cell attachment (% of sense control; mean±SEM, n=5), Statistical differences are denoted by an * p<0.01 as shown in FIG. 5 . In addition to the methods and results presented herein, methods and results described in “Simon D, Vadakkadath Meethal S. Wilson A C, et al, Activin receptor signaling regulates prostatic epithelial cell adhesion and viability. Neoplasia 11:365-376” the disclosure of which is incorporated herein in its entirety.
The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
Sequence Listing
ActRIIA antisense-P:
5′-TCCAGTTCAGAGTCCCATTTC-3′
SEQ ID NO 1
ActRIIA sense:
5′-GAAATGGGACTCTGAACTGGA-3′
SEQ ID NO 2
ActRIIB antisense-P:
5′-TCTCCCGTTCACTCTGCCAC-3′
SEQ ID NO 3
ActRIIB sense:
5′-GTGGCAGAGTGAACGGGAGA-3′
SEQ ID NO 4
ADAM-15 Antisense-P:
5′-CGCACTCTTCCCTGGTAGCA-3′
SEQ ID NO 5
ADAM-15 Sense:
5′-TGCTACCAGGGAAGAGTGCG-3′
SEQ ID NO 6
laminin molecules
GTFALRGDNGDNGQ
SEQ ID NO 7
REFERENCES
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2. Klein C A 2008 Cancer. The metastasis cascade. Science 321:1785-7
3, Chiang A C, Massague J 2008 Molecular basis of metastasis. N Engl Med 359:2814-23
4. Simon D, Vadakkadath Meethal S, Wilson A C, et al. 2009 Activin receptor signaling regulates prostatic epithelial cell adhesion and viability. Neoplasia 11:365-376
5. Rocks N, Paulissen G, El Hour M, et al. 2007 Emerging roles of ADAM and ADAMTS metalloproteinases in cancer. Biochimie
6. Najy A J, Day K C, Day M L 2008 ADAM15 supports prostate cancer metastasis by modulating tumor cell-endothelial cell interaction. Cancer Res 68:1092-9
7. Kuefer R, Day K C, Kleer C G, et al. 2006 ADAM15 disintegrin is associated with aggressive prostate and breast cancer disease. Neoplasia 8:319-29
8. Yamada D. Ohuchida K, Mizumoto K, et al. 2007 Increased expression of ADAM 9 and ADAM 15 mRNA in pancreatic cancer, Anticancer Res 27:793-9
9, Martin J, Eynstone L V, Davies M, Williams J D, Steadtnan R 2002 The role of ADAM 15 in glomerular mesangial cell migration. J Biol Chem 277:33683-9
10. Charrier-Hisamuddin L, Laboisse C L, Merlin D 2007 ADAM-15: a metalioprotease that mediates inflammation. Faseb J
11, Jeruss J S, Sturgis C D, Rademaker A W, Woodruff T K 2003 Down-regulation of activin, activin receptors, and Smads in high-grade breast cancer. Cancer Res 63:3783-90
12, Guo Y, Jacobs S C, Kyprianou N 1997 Down-regulation of protein and mRNA expression for transforming growth factor-beta (TGF-beta1) type I and type II receptors in human prostate cancer, Int J Cancer 71:573-9
13. Leto G, Incorvaia L, Badalamenti C, et al. 2006 Aetivin A circulating levels in patients with bone metastasis from breast or prostate cancer. Clin Exp Metastasis 23:117-22
14. Kaighn M E, Lechner J F, Narayan K S, Jones L W 1978 Prostate carcinoma: tissue culture cell lines. Natl Cancer Inst Monogr: 17-21
15, Kaighn M E, Narayan K S, Ohnuki Y, Lechner J F, Jones L W 1979 Establishment and characterization of a human prostatie carcinoma cell line (PC-3), Invest Urol 17:16-23
Appendix 1
Keratinizing epithelial cells such as epidermal keratinocyte (differentiating epidermal cell), epidermal basal cell (stem cell), keratinocyte of fingernails and toenails, nail bed basal cell (stem cell), medullary hair shaft cell, cortical hair shaft cell, cuticular hair shaft cell, cuticular hair root sheath cell, hair root sheath cell of Huxley's layer, hair root sheath cell of Henle's layer, external hair root sheath cell, hair matrix cell (stein cell).
Wet stratified barrier epithelial cells such as surface epithelial cell of stratified squamous epithelium of cornea, tongue, oral cavity, esophagus, anal canal, distal urethra and vagina, nasal cell (stem cell) of epithelia of cornea, tongue, oral cavity, esophagus, anal canal, distal urethra and vagina, urinary epithelium cell (lining urinary bladder and urinary ducts).
Exocrine secretory epithelial cells such as salivary gland mucous cell (polysaccharide-rich secretion), salivary gland serous cell (glycoprotein enzyme-rich secretion), von Ebner's gland cell in tongue (washes taste buds), mammary gland cell (milk secretion), lacrimal gland cell (tear secretion), ceruminous gland cell in ear (wax secretion), eccrine sweat gland dark cell (glycoprotein secretion), eccrine sweat gland clear cell (small molecule secretion), apocrine sweat gland cell (odoriferous secretion, sex-hormone sensitive), gland of Moll cell in eyelid (specialized sweat gland), sebaceous gland cell (lipid-rich sebum secretion), Bowman's gland cell in nose (washes olfactory epithelium), Brunner's gland cell in duodenum (enzymes and alkaline mucus), seminal vesicle cell (secretes seminal fluid components, including fructose for swimming sperm), prostate gland cell (secretes seminal fluid components), bulbourethral gland cell (mucus secretion), Bartholin's gland cell (vaginal lubricant secretion), gland of Littre cell (mucus secretion), uterus endometrium cell (carbohydrate secretion), isolated goblet cell of respiratory and digestive tracts (mucus secretion stomach lining mucous cell (mucus secretion), gastric gland zymogenic cell (pepsinogen secretion), gastric gland oxyntic cell (hydrochloric acid secretion), pancreatic acinar cell (bicarbonate and digestive enzyme secretion), Paneth cell of small intestine (lysozyme secretion), type II pneumocyte of lung (surfactant secretion), Clara cell of lung.
Hormone secreting cells such as anterior pituitary cells, somatotropes, lactotropes, thyrotropes, gonadotropes, corticotropes, intermediate pituitary cell, secreting melanocyte-stimulating hormone, magnocellular neuroseqretory cells, cells secreting oxytocin, secreting vasopressin, gut and respiratory tract cells, secreting serotonin, secreting endorphin, secreting somatostatin, secreting gastrin, secreting secretin, secreting cholecystokinin, secreting insulin, secreting glucagon, secreting bombesin, thyroid gland cells, thyroid epithelial cell, parafollicular cell, parathyroid gland cells, parathyroid chief cell, oxyphil cell, adrenal gland cells, chromaffin cells, secreting steroid hormones (mineralcorticoids and gluco corticoids), leydig cell of testes secreting testosterone, theca interna cell of ovarian follicle secreting estrogen, corpus luteum cell of ruptured ovarian follicle secreting progesterone, granulosa lutein cells, theca lutein cells, juxtaglomerular cell (renin secretion), macula densa cell of kidney, peripolar cell of kidney, mesangial cell of kidney. Metabolism and storage cells such as hepatocyte (liver cell), white fat cell, brown fat cell, liver lipocyte.
Barrier function cells of lung, gut, exocrine glands and urogenital tract. Kidney cells such as kidney glomerulus parietal cell, kidney glomerulus podocyte, kidney proximal tubule brush border cell, Loop of Henle thin segment cell, kidney distal tubule cell, kidney collecting duct cell.
Epithelial cells lining closed internal body cavities such as blood vessel and lymphatic vascular endothelial fenestrated cell, blood vessel and lymphatic vascular endothelial continuous cell, blood vessel and lymphatic vascular endothelial splenic cell, synovial cell (lining joint cavities, hyaluronie acid secretion), serosal cell (lining peritoneal, pleural, and pericardial cavities), squamous cell (lining perilymphatic space of ear), squamous cell (lining endolymphatic space of ear), columnar cell of endolymphatic sac with microvilli (lining endolymphatic space of ear), columnar cell of endolymphatic sac without microvilli (lining endolymphatic space of ear), dark cell (lining endolymphatic space of ear), vestibular membrane cell (lining endolymphatic space of ear), stria vascularis basal cell (lining endolymphatic space of ear), stria vascularis marginal cell endolymphatie space of ear), cell of Claudius (lining endolymphatic space of ear), cell of Boettcher (lining endolymphatic space of ear), choroid plexus cell (cerebrospinal fluid secretion), pia-arachnoid squamous cell, pigmented ciliary epithelium cell of eye, nonpigmented ciliary epithelium cell of eye, corneal endothelial cell.
Ciliated cells with propulsive function such as respiratory tract ciliated cell, oviduct ciliated cell (in female), uterine endometrial ciliated cell (in female), rete testis ciliated cell (in male), ductulus efferens ciliated cell (in male), ciliated ependymal cell of central nervous system (lining brain cavities).
Extracellular matrix secretion cells such as ainelobiast epithelial cell (tooth enamel secretion), planum semilunatum epithelial cell of vestibular apparatus of ear (proteoglycan secretion), organ of Corti interdental epithelial cell (secreting tectorial membrane covering hair cells), loose connective tissue fibroblasts, corneal fibroblasts, tendon fibroblasts, bone marrow reticular tissue fibroblasts, other nonepithelial fibroblasts such as pericyte, nucleus pulposus cell of intervertebral disc, cementoblast/cementocyte (tooth root bonelike cementum secretion), odontoblast/odontocyte (tooth dentin secretion), hyaline cartilage chondrocyte, fibrocartilage chondrocyte, elastic cartilage chondrocyte, osteoblast/osteocyte, osteoprogenitor cell (stem cell of osteoblasts), hyalocyte of vitreous body of eye, stellate cell of perilymphatic space of ear contractile cells such as skeletal muscle cells, red skeletal muscle cell (slow), white skeletal muscle cell (fast), intermediate skeletal muscle cell, nuclear bag cell of muscle spindle, nuclear chain cell of muscle spindle, satellite cell (stem cell), heart muscle cells such as ordinary heart muscle cell, nodal heart muscle cell, purkinje fiber cell, smooth muscle cell (various types), myoepithelial cell of iris, myoepithelial cell of exocrine glands.
Blood and immune system cells such as erythrocyte (red blood cell), megakaryocyte (platelet precursor), monocyte, connective tissue macrophage (various types), epidermal Langerhans cell, osteoclast (in bone), dendritic cell (in lymphoid tissues), microglial cell (in central nervous system), neutrophil granulocyte, eosinophil granulocyte, basophil granulocyte, mast cell, helper cell, suppressor T cell, cytotoxic T cell, natural Killer T cell, B cell, natural killer cell, reticulocytes, stem cells and committed progenitors for the blood and immune system (various types).
Cells of the nervous system such as sensory transducer cells which include auditory inner hair cell of organ of Corti, auditory outer hair cell of organ of Corti, basal cell of olfactory epithelium (stem cell for olfactory neurons), cold-sensitive primary sensory neurons, heat-sensitive primary sensory neurons, merkel cell of epidermis (touch sensor), olfactory receptor neuron, pain-sensitive primary sensory neurons (various types), photoreceptor cells of retina in eye (Photoreceptor rod cells, photoreceptor blue-sensitive cone cell of eye, photoreceptor green-sensitive cone cell of eye, photoreceptor red-sensitive cone cell of eye), proprioceptive primary sensory neurons (various types), touch-sensitive primary sensory neurons (various types), type I carotid body cell (blood pH sensor), type II carotid body cell (blood pH sensor), type I hair cell of vestibular apparatus of ear (acceleration and gravity), type II hair cell of vestibular apparatus of ear (acceleration and gravity), type I taste bud cell.
Autonomic neuron cells such as cholinergic neural cell (various types), adrenergic neural cell (various types), peptidergic neural cell (various types).
Sense organ and peripheral neuron supporting cells such as inner pillar cell of organ of Corti, outer pillar cell of organ of Corti, inner phalangeal cell of organ of Corti, outer phalangeal cell of organ of Corti, border cell of organ of Corti. Hensen cell of organ of Corti, vestibular apparatus supporting cell, type I taste bud supporting cell, olfactory epithelium supporting cell, Schwann cell, satellite cell (encapsulating peripheral nerve cell bodies), enteric glial
Central nervous system neurons and glial cells such as astrocyte (various types), neuron cells (large variety of types, still poorly classified), oligodendrocyte, spindle neuron.
Lens cells such as anterior lens epithelial cell, crystallin-containing lens fiber cell.
Pigment cells such as melanocyte, retinal pigmented epithelial cell.
Germ cells such as oogonium/oocyte, spermatid, spermatocyte, spermatogonium cell
(stem cell for spermatocyte), spermatozoon.
Nurse cells such as ovarian follicle cell, sertoli cell (in testis), thymus epithelial cell.
Interstitial cells like interstitial kidney cells.
Stem cells such as embryonic stem cells, mesenchymal stem cells, subcutaneous preadipocytes, visceral preadipocytes, osteoclast precursors, neural progenitors, bone marrow mononuclear cells, cord blood mononuclear cells, bone marrow progenitors, cord blood progenitors, cord blood erythroid progenitors, fetal liver progenitors, bone marrow stromal cells.
Other cells such as type I pneumocyte (lining air space of lung), pancreatic duet cell (centroacinar cell), nonstriated duct cell (of sweat gland, salivary gland, mammary gland, etc.), principal, cell, intercalated cell, duct cell (of seminal vesicle, prostate gland, etc.), intestinal brush border cell (with microvilli), exocrine gland striated duct cell, gall bladder epithelial cell, ductulus efferens nonciliated cell, epididymal principal cell, epididymal basal cell.
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Disclosed are methods for identification of agents that modulate cell attachment, cell migration and cell viability. Cancer and primary cells adhered to a matrix are treated with agent(s) that modulate ActRII signaling and cell adhesion. Agents are tested that modulate cell adhesion, detachment, invasion and viability. Agents that modulate the expression, phosphorylation, function and translocation of ActRII signaling pathway members also can predict agents that modulate cell adhesion, detachment, invasion and viability. The methods have utility in identifying agents that prevent cancer cell metastasis, wound dehiscence, aortic dissection and aid retina attachment and skin replacement and fertility.
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BACKGROUND OF THE INVENTION
Entertainment center consoles of varying constructs have long been used to support television sets and house the various electronic accessories, such as cable converter boxes, VCR's and satellite receivers, which often accompany them. However, with the rise in popularity of flat panel televisions, which tend to be lighter and smaller than their predecessor televisions of comparable monitor size, stands of various configurations for enabling televisions to be mounted to walls or suspended from ceilings have been developed in the prior art. In many homes and other facilities, such stands have largely replaced entertainment center consoles due to the fact that they occupy considerably less space. Consequently, wall-mounted open shelves have become popular means for supporting the electronic accessories that were previously stored in entertainment console cabinets. However, some consumers prefer electronics mounting solutions other than horizontal shelves. Among other things, open shelves present the dangerous specter of equipment cascading down from them and landing upon unsuspecting children who may have occasion to tug on the equipment cords.
Mounting apparatuses that provide adjustable perimeter support for electronic devices have been developed as well. For example, U.S. Pat. No. 6,318,692 to Cyrell discloses an adjustable framing support system comprised of elongate side frame components which are connected by corner frame components to form a typically rectangular enclosure. The side components slide relative to the corner components, and the all have a continuous internal slot through which a cable is threaded so that the entire frame circumference contracts in response to the cable being drawn. This support system is to be placed around the lateral perimeter of an electronic device and adjusted to snugly fit thereabout. Another example is disclosed in U.S. Pat. No. 6,460,817 to Bosson. Specifically, Bosson teaches a perimeter support frame constructed of four L-shaped pieces that are in sliding relation to form a rectangular enclosure that adjustably fits around the lateral perimeter of an electronic device. The frame can be mounted to a horizontal or vertical surface to suspend the equipment from the floor. It is anticipated that the Bosson support is to be used to hold computer central processing units, but it certainly could be used to retain other types of electronic devices.
Nevertheless, there remains a need for an improved, space efficient holding apparatus that can be adjusted to fit snugly around a box-shaped electronic device so that it cannot be accidentally dislodged from the holding apparatus and that configured to mount to a vertical surface, such as a wall or the side of an entertainment center. The present invention substantially fulfills this need.
SUMMARY OF THE INVENTION
The present invention generally relates to apparatuses for mounting objects, and it is specifically directed to an apparatus that can be affixed to a wall or other flat surface and which has a rectangular frame that can be expanded and contracted bi-directionally to grip and securely retain most rectangular box-shaped electronic devices.
It is an object of the present invention to provide an apparatus for securely mounting an electronic audio or video device against a wall.
It is another object of the invention that the apparatus include a rectangular frame that can be expanded and contracted along two axes so as to be able to conform to the perimeter of rectangular box-shaped electronic devices of varying lengths and widths.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a bottom perspective view of the device holder of the present invention;
FIG. 2 is a top perspective view of the device holder;
FIG. 3 is a bottom perspective view of a connector;
FIG. 4 is a top perspective view of a connector;
FIG. 5 is a top perspective view of a retainer; and
FIG. 6 is a top perspective view of the base.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIGS. 1 and 2 , a preferred embodiment of the expandable device holder 1 broadly comprises a base support 4 to which a rectangular perimeter frame 6 is operatively attached. As will be explained, the frame 6 is slidably expandable in the L and W directions so that it may be conformed to the lengths and widths of rectangular box-shaped devices that would be inserted into it.
As depicted in FIG. 6 , the base 4 preferably has a moderately thick rectangular profile and features four non-contiguous, insertion pockets 5 (only one of which is shown) formed within its perimeter sides. Multiple threaded holes 7 extend through the base so that screws 50 may be inserted to bind the plate to a flat surface, such as a wall. The perimeter frame 6 is formed by four generally L-shaped retaining elements 30 which, themselves, are held together in an expandable rectangular configuration by four generally T-shaped connecting elements 10 .
As more clearly illustrated in FIG. 5 , each retainer 30 comprises two elongate slats 32 that are perpendicularly joined by a corner bracket 34 , 36 . As shown in FIGS. 3 and 4 , each connector 10 is formed by an elongate arm 16 and a linear slide track 12 that is perpendicularly joined at the distal end 20 of the arm 16 . The connector arm slides into an insertion pocket 5 within the base plate. Running down each connector arm 16 is a notched slot 17 , and within the base 4 are holes 9 axially aligned with the slots 17 . Therefore, pins or screws (not shown) may be inserted through the base 4 and the connector arms 16 in order to fix the connectors 10 relative to the base 4 and thereby fix the length or width of the perimeter frame 6 .
Formed within each connector's slide track 12 are parallel upper and lower slide grooves 11 , 13 within which the L-shaped retainer slats 32 are slidably held. The L-shaped retainers 30 are positioned at right angles to one another to form a rectangular enclosure. Consequently, when both pairs of opposing connectors 10 are fully extended from the base 4 , the diagonally facing corner brackets 34 , 36 are spaced furthest apart and vice versa. In fact, the slide track portion 12 of a connector 10 can be fixedly positioned right alongside the base 4 , as far away from the base 4 as the connector arm 16 will permit or anywhere therebetween. Preferably, the proximal end 18 of the connector arm 16 is flanged to prevent it from dislodging from the base 4 .
At the corners of the L-shaped retainers 30 are L-shaped corner brackets 34 , 36 for fitting over the corners of a box-shaped electronic device (not shown). More specifically, the brackets 34 , 36 are configured so that at the front end of the frame 6 , the brackets 34 face each other, and at the rear end of the frame 6 , the brackets 36 both face their adjacent front end counterparts 34 . This orientation ensures retention of three of the four perimeter sides of an electronic device which is set within the partial enclosure formed by the retainers 30 and their corner brackets 34 , 36 . The front end of the holding apparatus 1 is left unrestricted so that the device can slid in and out of the frame 6 .
Preferably, the undersides of the perimeter frame 6 feature cable wire guides 40 so that a held electronic device's cable can be directed along the holder as may be appropriate.
Although the present invention has been described in some detail and with reference to and illustration of a preferred version and reference to various alternative embodiments, it should be understood that other versions are contemplated as being a part of the present invention.
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An apparatus expanding around the perimeter of a box-shaped electronic device, the apparatus having a rectangular frame which is expandable lengthwise and widthwise and brackets for three-dimensional retention of an electronic device.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Patent Application No. 10-2008-0122426 filed on Dec. 4, 2008, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND
1. Field
The present invention relates to a refrigerator and a method of controlling the same. More particularly, the present invention relates to a refrigerator equipped with a door opening device enabling a user to easily open a door of the refrigerator and a method of controlling the refrigerator.
2. Description of the Related Art
Generally, a refrigerator cools articles stored therein through a cooling cycle of a compressor, a condenser, and an evaporator. The refrigerator is provided therein with a storage compartment to allow a user to store and take out the articles in the refrigerator. The refrigerator includes at least one storage compartment according to the capacity of the refrigerator. For example, the storage compartment may be divided into two compartments, such as a cooling compartment and a refrigerating compartment, or may be divided into four compartments, such as a cooling compartment, a refrigerating compartment, an auxiliary cooling compartment, and an auxiliary refrigerating compartment.
Meanwhile, the refrigerator having at least one storage compartment includes a door, which opens/closes the storage compartment. The door is divided into a hinge coupling type door that is rotatably open/closed relative to the storage compartment and a drawer type door that is open/closed relative to the storage compartment like a drawer.
Meanwhile, typically, a user must pull a door of a refrigerator when the user wants to manually open the door. In addition, when the user wants to close the door, the user must push the door using a hand or a foot such that the door can be closed by the weight thereof.
SUMMARY
Accordingly, it is an aspect of the present invention to provide a refrigerator and a method of controlling the same, capable of automatically opening/closing a door using a motor.
In addition, it is another aspect of the present invention to provide a refrigerator and a method of controlling the same, capable of reducing noise in the process of changing a direction of a motor when a door is open/closed.
Further, it is still another aspect of the present invention to provide a refrigerator and a method of controlling the same, capable of setting a door in an initial position when the refrigerator is powered on.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.
The foregoing and/or other aspects of the present invention are achieved by providing a refrigerator including first and second doors which open/close first and second storage compartments defined in a body, respectively, and a door opening device. The door opening device includes a plurality of sliding bars which selectively open the first and second doors, and a motor which opens/closes the first door or the second door by moving back and forth the sliding bars in directions opposite to each other.
The door opening device may further include a switch unit inputting a door opening signal used to open the first door or the second door.
The door opening device may further include a controller controlling the first door or the second door to be open according to the door opening signal input to the switch unit.
The door opening device may further include a plurality of position detectors detecting at least one protrusion provided at one side of the sliding bars.
The door opening device may further include a display unit displaying failure of the door opening device.
According to another aspect of the present invention, there is provided a method of controlling a refrigerator including a door opening device, which includes first and second doors opening/closing first and second storage compartments defined in a body, a plurality of sliding bars selectively opening the first and second doors, a motor opening the first door or the second door by moving back and forth the sliding bars in directions opposite to each other, a plurality of position detectors detecting at least one protrusion provided in one side of the sliding bars, a switch unit inputting door opening signals, and a controller controlling operation of the first and second doors according to the door opening signals, and the method includes opening/closing the first and second doors by controlling the door opening device if the door opening signals are input in order to open the first door or the second door.
The sliding bar may be moved by driving the motor for a first set time sufficient for enabling the at least one protrusion to deviate from a detection region of the position detector if the door opening signals are input.
A time point, at which the at least one protrusion enters the detection region of the position detector, is recognized if the first set time elapses.
The sliding bar may be moved by driving the motor for a second set time sufficient for enabling the at least one protrusion to enter a reliable detection region of the position detector if the at least one protrusion has entered the detection region of the position detector.
The motor may be stopped if the second set time elapses, so that the first door or the second door maintains an open state for a third set time.
The sliding bar may be moved by driving the motor for a fourth set time sufficient for enabling the at least one protrusion to deviate from the detection region of the position detector if the third set time elapses.
The time point, at which the at least one protrusion enters the detection region of the position detector, is recognized if the fourth set time elapses.
The sliding bar may be moved by driving the motor for a fifth set time sufficient for enabling the at least one protrusion to enter the reliable detection region of the position detector if the at least one protrusion has entered the detection region of the position detector.
If the door opening signals of the first and second doors are simultaneously input, the controller may determine an input sequence of the door opening signals to recognize only the door opening signal that is primarily input such that one of the first and second doors corresponding to the primary door opening signal is open.
If the door opening signals of the first and second doors are simultaneously input, the controller may not recognize all the door opening signal, or recognizes only the door opening signal of a preset door.
If the door opening signal for one of the first and second doors is input when a remaining one door is open/closed, the door opening signal may not be recognized.
According to still another aspect of the present invention, there is provided a method of controlling a refrigerator equipped with first and second doors opening/closing first and second storage compartments partitioned in a body. The refrigerator includes a door opening device including a plurality of sliding bars selectively opening the first and second doors, a motor opening the first door or the second door by moving back and forth the sliding bars in directions opposite to each other, a plurality of position detectors detecting at least one protrusion provided at one side of the sliding bar, a switch unit inputting door opening signals, and a controller controlling operation of the first door and the second door according to the door opening signals. The method of controlling the refrigerator includes detecting a position of the at least one protrusion if the refrigerator is powered on, and controlling the first and second doors to be closed according to a position of the at least one protrusion.
The method may further include rotating the motor in one preset direction if the position of the at least one protrusion is not detected.
The method may further include controlling the first and second doors such that the first and second doors are closed according to the position of the at least one protrusion if the position of the at least one protrusion is detected due to the rotating of the motor.
The method may further include recognizing that the at least one protrusion is placed at a preset position if the at least one position of the protrusion is not detected.
The method may further include controlling the first and second doors such that the first and second doors are closed according to the at least one position of the protrusion.
If the position of the at least one protrusion is not detected for a predetermined time when the first and second doors are controlled to be closed, the door opening device may be regarded as failed.
The door opening device may further include a display unit, and the display unit displays failure of the door opening device if the door opening device is regarded as failed.
As described above, according to one aspect, a plurality of doors can be open by moving two sliding bars using one motor, so that the manufacturing cost can be reduced.
According to another aspect, when a door is open due to the rotation of the motor, or the door position is changed from the maximum open state to a closed state, the operation of the door is performed after a predetermined time has elapsed, so that noise can be reduced when the door is open/closed.
According to still another aspect, when power is turned off and then turn on due to cut-off of electric current, a state of the door can be exactly determined by the position detectors, so that the door can return to a waiting state without an unnecessary operation.
BRIEF DESCRIPTION OF THE DRAWINGS
These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a view showing a refrigerator employing a door opening device according to one embodiment;
FIG. 2 is a control block diagram showing the door opening device according to one embodiment;
FIGS. 3A to 3C are schematic views showing a door opening device according to a first embodiment;
FIG. 4 is a view showing a table representing the detection state of position detectors based on the open state of doors according to the first embodiment;
FIGS. 5A and 5B are flowcharts showing the control procedure of the door opening device according to the first embodiment;
FIG. 6 is a flowchart showing an initialization operation when the door opening device is powered on according to the first embodiment;
FIGS. 7A to 7E are sectional views schematically showing a door opening device according to a second embodiment;
FIG. 8 is a table showing the detection state of position detectors when a door is open according to the second embodiment; and
FIG. 9 is a flowchart showing an initialization operation of the door opening device upon a power-on state according to the second embodiment.
DETAILED DESCRIPTION OF EMBODIMENTS
Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements. The embodiments are described below by referring to the figures.
FIG. 1 is a view showing a refrigerator employing a door opening device 20 according to one embodiment.
As shown in FIG. 1 , the refrigerator according to one embodiment includes a body 10 divided into a first storage compartment (not shown) and a second compartment (not shown). First and second doors 11 and 12 are installed at both sides of a front surface of the body 10 to open/close the first and second storage compartments. Generally, in such a refrigerator, the first storage compartment serves as a cooling compartment, and the second storage compartment serves as a refrigerating compartment. Upper and lower portions of the first and second doors 11 and 12 are pivotally coupled to the body 10 by a hinge assembly 13 . In addition, first and second handles 14 and 15 are provided on front surfaces of the first and second doors 11 and 12 .
The door opening device 20 may be mounted on a top surface of the body 10 to push the upper portions of the first and second doors 11 and 12 forward and open the first and second doors 11 and 12 , so that a user can easily open the first and second doors 11 and 12 .
FIG. 2 is a control block diagram showing the door opening device 20 according to one embodiment.
As shown in FIG. 2 , the door opening device 20 includes first and second switch units 16 and 17 allowing a user to input a door opening signal, first, second, and third position detectors 31 , 32 , and 33 detecting positions of first and second sliding bars 40 and 41 , a memory 34 storing a program to control the operation of a motor 38 , a timer 35 measuring a driving time of the motor 38 , a controller 30 controlling the driving of the motor 38 using information from the first to third position detectors 31 to 33 and the timer 35 , a motor driver 36 driving the motor 38 under the control of the controller 30 , and a display unit 37 displaying the failure of the door opening device 20 .
The first and second switch units 16 and 17 are provided at the first and second handles 14 and 15 of the first and second doors 11 and 12 to allow a user to control the operation of the motor 38 . The first and second switch units 16 and 17 may be detectors that detect touch of the user on the first and second handles 14 and 15 , or power switches that directly turn on/off power applied to the motor 38 .
The first to third position detectors 31 to 33 may detect a rotation position of the motor 38 , that is, a position of the first and second sliding bars 40 and 41 . The first to third position detectors 31 , 32 , and 33 may detect the rotation position of the motor 38 by detecting first, second, and third protrusions 42 , 43 , and 44 . In addition, the first to third position detectors 31 to 33 may be a typical optical sensor. According to the present embodiment, the first to third position detectors 31 to 33 are turned on if a signal phase is changed due to the first and second protrusions 42 and 43 , and turned off if the signal phase is not changed.
The memory 34 stores a program to control the operation of the motor 38 , and the timer 35 can measure the driving time of the motor 38 .
The controller 30 can transmit an operational control signal for the motor 38 to the motor driver 36 according to the program previously stored in the memory 34 by using door opening signals of the first and second switches 16 and 17 , information delivered from the first to third position detectors 31 to 33 , and the timer 35 .
The display unit 37 may be a display (not shown) positioned on the front surface of the body 10 of the refrigerator, and can display the failure of the door opening device 20 .
FIGS. 3A to 3C are schematic views showing the door opening device 20 according to a first embodiment of the present invention.
As shown in FIG. 3A , the door opening device 20 according to the first embodiment includes the first and second sliding bars 40 and 41 capable of selectively opening the two first and second doors 11 and 12 , the motor 38 moving the sliding first and second bars 40 and 41 , the first and second position detectors 31 and 32 capable of detecting the positions of the first and second sliding bars 40 and 41 , and the first and second protrusions 42 and 43 protruding from one side of the first sliding bar 40 to be detected by the first and second position detectors 31 and 32 .
The first and second sliding bars 40 and 41 are geared with both sides of the motor 38 (e.g., a rack and a pinion assembly) to selectively push the two first and second doors 11 and 12 . The two first and second protrusions 42 and 43 are provided on the first sliding bar 40 to detect the position of the first sliding bar 40 by the first and second position detectors 31 and 32 . Meanwhile, as shown in FIG. 3A , although the two first and second protrusions 42 and 43 are provided at one side of the first sliding bar 40 , the two first and second protrusions 42 and 43 may be provided at one side of the second sliding bar 41 .
The motor 38 is geared with the first and second sliding bars 40 and 41 (e.g., a rack and a pinion assembly) to rotate. When the motor 38 rotates in a first direction (clockwise), the first door 11 can be open by the first sliding bar 40 . When the motor 38 rotates in a second direction (counterclockwise), the second door 12 can be open by the second sliding bar 41 .
The first and second position detectors 31 and 32 may be installed in order to detect the rotation position of the motor 38 , that is, the position of the first sliding bar 40 . The first and second position detectors 31 and 32 detect the two first and second protrusions 42 and 43 of the first sliding bar 40 through an optical sensor (not shown) to detect the rotation position of the motor 38 . In addition, the first and second position detectors 31 and 32 include typical optical sensors. According to one embodiment, the first and second position detectors 31 and 32 are turned on if the signal phase is changed by the two first and second protrusions 42 and 43 , and turned off if the signal phase is not changed.
Meanwhile, the present invention is not limited to the first and second position detectors 31 and 32 , but can employ a lead switch to detect the positions of the first and second protrusions 42 and 43 and a limit switch to detect the positions of the first and second protrusions 42 and 43 in the contact with the first and second protrusions 42 and 43 .
Hereinafter, the operation of the door opening device 20 will be described with reference to FIGS. 3B and 3C .
If a user grasps or pulls the second handle 15 of the first door 11 in order to open the first door 11 , the motor 38 operates with the manipulation of the second switch unit 17 . In this case, as shown in FIG. 3B , the motor 38 rotates in the first direction (clockwise) to push the first sliding bar 40 geared with the motor 38 (e.g., a rack and a pinion assembly) forward so that the first door 11 can be opened. If the first position detector 31 detects the second protrusion 43 of the first sliding bar 40 , and the second position detector 32 does not detect any protrusion, it is determined that the first door 11 is at the maximum open state, and the motor 38 is stopped. Meanwhile, according to one embodiment, when open commands of the first and second doors 11 and 12 are issued, the first and second doors 11 and 12 are open through the driving of the motor 38 , and then, when a predetermined time elapses, the first and second doors 11 and 12 are closed. Details thereof will be described later.
In addition, if the user grasps or pulls the first handle 14 of the second door 12 in order to open the second door 12 , the motor 38 rotates in the second direction (counterclockwise) with the manipulation of the first switch unit 16 to push the second sliding bar 41 forward, so that the second door 12 is open. In addition, if the second position detector 32 detects the first protrusion 42 , and the first position detector 31 does not detect any protrusion, it is determined that the door 12 has the maximum open state, and the motor 38 is stopped.
FIG. 4 is a view showing a table representing the detection state of the first and second position detectors 31 and 32 based on the open state of the first and second doors 11 and 12 according to the first embodiment.
As shown in FIG. 4 , when the first and second position detectors 31 and 32 detect all of the first and second protrusions 42 and 43 , the first and second doors 11 and 12 of the refrigerator are in a waiting state, that is, a closed state.
In addition, if the first position detector 31 detects a protrusion, and the second position detector 32 does not detect a protrusion, the controller 30 determines that the first door 11 is open. In contrast, if the first position detector 31 does not any protrusion, and the second position detector 32 detects a protrusion, the controller 30 determines that the second door 12 is open.
If both of the first and second position detectors 31 and 32 do not detect the first and second protrusions 42 and 43 , the controller 30 may determine that the first door 11 or the second door 12 is open or is being opened.
FIGS. 5A and 5B are flowcharts showing the control procedure of the door opening device 20 according to the first embodiment.
As shown in FIG. 5A , if an open command of the first door 11 or the second door 12 of the refrigerator according to one embodiment is input, the motor 38 is driven. In other words, if a user grasps or pulls the first or second switch unit 16 or 17 provided on the first or second handle 14 or 15 of the first or second door 11 or 12 to control the operation of the motor 38 , the motor 38 is driven with the operation of the first or second switch unit 16 or 17 . In detail, if the user manipulates the second switch 17 provided on the second handle 15 of the first door 11 , the motor 38 rotates in the first direction (clockwise). If the user manipulates the first switch 16 provided on the first handle 14 , the motor 38 rotates in the second direction (counterclockwise) (operation S 10 and S 20 ).
Subsequently, if the motor 38 is driven due to the user manipulation of the first switch unit 16 or the second switch unit 17 , the controller 30 measures a time, in which the motor 38 is driven, to determine if a first preset time elapses. The first preset time is previously stored in the memory 34 , and is obtained by experimentally calculating a time spent until the first and second protrusions 42 and 43 of the first sliding bar 40 deviate from detection regions of the first and second position detectors 31 and 32 after the motor 38 in the waiting state is driven (operation S 30 ).
Next, if the controller 30 determines that the first preset time has elapsed in operation S 30 , the controller 30 determines if a first state comes. In this case, the first state means an initial time point at which the first protrusion 42 enters the detection region of the second position detector 32 or the second protrusion 43 enters the detection region of the first position detector 31 due to continuous rotation of the motor 38 after the first and second protrusions 42 and 43 of the first sliding bar 40 have deviated from the detection regions of the first and second position detectors 31 and 32 (operation S 40 ).
Thereafter, the controller 30 determines if a second preset time elapses after the first state is determined in operation S 40 . The second preset time is previously stored in the memory 34 , and means a time spent until the first protrusion 42 of the first sliding bar 40 or the second protrusion 43 moves into a reliable detection region of the second position sensor 32 or the first position sensor 31 from the initial time point at which the first protrusion 42 enters the detection region of the second position detector 32 or the second protrusion 43 enters the detection region of the first position detector 31 (operation S 50 ).
Next, if the controller 30 determines that the second preset time has elapsed in operation S 50 , the controller 30 stops the motor 38 and determines if a third preset time elapses. In this case, the third preset time is previously stored in the memory 34 , and means a time, in which the motor 38 is stopped, in order to reduce noise created when the direction of the motor 38 is changed (operations S 60 and S 70 ).
As shown in FIG. 5B , if the third preset time has elapsed in operation S 70 , the controller 30 drives the motor 38 . In other words, the controller 30 rotates the motor 38 in directions opposite to a direction, in which the motor 38 has rotated in operations S 20 to S 50 , to commence to close the first door 11 or the second door 12 again (operation S 80 ).
Then, if the motor 38 is driven, the controller 30 measures the driving time of the motor 38 to determine if a fourth preset time has elapsed. The fourth preset time is previously stored in the memory 34 . In addition, the fourth preset time is obtained by experimentally calculating a time spent until the motor 38 is driven in a door open state so that the first protrusion 42 or the second protrusion 43 of the sliding bar 40 deviates from the detection region of the second position detector 32 or the first position detector 31 (operation S 90 ).
Thereafter, if the fourth preset time has elapsed in operation S 90 , the controller 30 determines if a second state comes. The second state means an initial time point at which the first and second protrusions 42 and 43 of the first sliding bar 30 enter the detection regions of the first and second position detectors 31 and 32 due to the continuous rotation of the motor 38 after the first protrusion 42 or the second protrusion has deviated from the detection region of the second position detector 32 or the first position detector 31 (operation S 100 ).
Then, the controller 30 determines if a fifth preset time has elapsed after the second state has come in operation S 100 . The fifth preset time is previously stored in the memory 34 , and means a time spent until the first protrusion 42 or the second protrusion 43 of the first sliding bar 40 moves into the reliable region of the second position detector 32 or the first position detector 31 from the initial time point at which the first protrusion 42 or the second protrusion 43 enters the detection region of the second position detector 32 or the first position detector 31 (operation S 110 ).
Thereafter, if the fifth preset time has elapsed in operation S 110 , the controller 30 stops the motor 38 to terminate a door opening/closing operation (operation S 120 ).
Meanwhile, the above operational procedure prevents the motor 38 from erroneously operating due to chattering. The chattering refers to a phenomenon in which an electrical contact is abnormally turned on/off for a very short time due to mechanical vibration. According to the present embodiment, the above operation procedure is performed in order to drive the motor 38 for several times previously stored in the memory 34 and open/close the first door 11 or the second door 12 , so that the motor 38 moves the sliding bar 40 or 41 into a reliable detection region of the position detectors 31 and 32 .
FIG. 6 is a flowchart showing an initialization operation when the door opening device 20 is powered on according to the first embodiment.
As shown in FIG. 6 , if power is applied to the refrigerator, the controller 30 turns on the timer 35 to set time (T) to ‘0’ (operations S 200 and S 210 ).
Then, the controller 30 determines if the time (T) of the timer 35 exceeds a preset time T. If the time (T) does not exceed the preset time T, the controller 30 determines if the first door 11 or the second door 12 of the refrigerator stays in a waiting state. In other words, the controller 30 determines if the first and second protrusions 42 and 43 are simultaneously detected by the second and first position detectors 32 and 31 , respectively, to determine if both of the first and second doors 11 and 12 are closed (operations S 220 and S 230 ).
Thereafter, if the first door 11 or the second door 12 of the refrigerator is in the waiting state in operation S 230 when power is applied to the first door 11 or the second door 12 of the refrigerator, the controller 30 determines the operational state of the motor 38 . If the motor 38 is driven, the controller 30 stops the operation of the motor 38 to terminate the initialization operation. However, if the first door 11 or the second door 12 is in the waiting state when power is applied to the refrigerator, since the motor 38 is in a stop state, the initialization operation is instantly terminated (operations S 260 and S 270 ).
Meanwhile, if the first door 11 or the second door 12 is not in the waiting state in operation S 230 , the controller 30 determines if the first door 11 is open. In other words, the controller 30 determines if the second protrusion 43 of the sliding bar 40 is detected by the first position detector 31 . However, the first and second position detectors 31 and 32 do not detect the type of the first and second protrusions 42 and 43 . Accordingly, if the first position detector 31 detects a protrusion, and the second position detector 32 does not detect a protrusion, the controller 30 determines that the first door 11 is open through the program previously stored in the memory 34 (operation S 240 ).
Thereafter, if the controller 30 determines that the first door 11 is open in operation S 240 , the controller 30 rotates the motor 38 in the second direction (counterclockwise) to move the first sliding bar 40 such that the first door 11 is closed (operation S 280 ).
Then, if the controller 30 determines that the first door 11 is not open in operation S 240 , the controller 30 determines if the second door 12 is open. In other words, the controller 30 determines that the first protrusion 42 of the first sliding bar 40 is detected by the second position detector 32 . However, the first and second position detectors 31 and 32 do not detect the type of the protrusions 42 and 43 . Accordingly, if the second position detector 32 detects the protrusion, and the first position detector 31 does not detect the protrusion, the controller 30 determines that the second door 12 is open through the program previously stored in the memory 34 (operation S 250 ).
Thereafter, if the controller 30 determines that the second door 12 is open in operation S 250 , the controller 30 rotates the motor 38 in the first direction (clockwise) to move the first sliding bar 40 such that the second door 12 is closed (operation S 290 ).
Meanwhile, if the controller 30 determines that the first door 11 or the second door 12 is not in any one of the waiting state, a first door open state, and a second door open state in operations S 230 to S 250 , the controller 30 rotates the motor 38 in a reference direction stored in the memory 34 . In other words, in the case of an open state of a certain door as shown in the table of FIG. 4 , that is, in the case in which the first and second position detectors 31 and 32 do not detect any protrusion, the controller 30 rotates the motor 38 in a preset direction and returns to operation S 220 to determine the state of the first door 11 or the second door 12 (operation S 300 ).
Thereafter, if the motor 38 is rotated in operations S 280 to S 300 , the controller 30 returns to operation S 220 to determine if the time T of the timer 45 exceeds the preset time T 1 . If the time T of the timer 45 does not the preset time T 1 , the controller 30 determines if the doors 11 and 12 are adjusted to the waiting state due to the rotation of the motor 38 . In this case, if the doors 11 and 12 do not become the waiting state until the time T of the timer 45 exceeds the preset time T 1 , the controller 30 stops the operation of the motor 38 , determines that the door opening device 20 is failed, and displays the failure of the door opening device 20 on the display unit 37 (operations S 310 to S 330 ).
If the door 11 or 12 becomes the waiting state within the preset time T 1 through the above procedure, the controller 30 determines the operational state of the motor 38 and then stops the motor 38 to terminate the initialization operation (operations S 260 and S 270 ).
FIGS. 7A to 7E are sectional views schematically showing the door opening device 20 according to a second embodiment, and FIG. 8 is a table showing detection states of position detectors as a door is open according to the second embodiment of the present invention. Meanwhile, the same reference numerals will be assigned to elements identical to those of FIG. 3A .
As shown in FIG. 7A , a door opening device 20 according to the second embodiment includes first and second sliding bars 40 and 41 capable of selectively opening two first and second doors 11 and 12 , a motor 38 moving the first and second sliding bars 40 and 41 , first, second, and third position detectors 31 , 32 , and 33 capable of detecting positions of the first and second sliding bars 40 and 41 , and first, second, and third protrusions 42 , 43 , and 44 protruding from one sides of the first and second sliding bars 40 and 41 to be detected by the first to third position detectors 31 to 33 .
The sliding bars 40 and 41 are geared with both sides of the motor 38 (e.g., a rack and a pinion assembly) such that the two first and second doors 11 and 12 can be selectively pushed, and the two first and second protrusions 42 and 43 are provided on the first sliding bar 40 to be detected by the first and second position detectors 31 and 32 . One protrusion 44 is provided on the second sliding bar 41 , so that the position of the second sliding bar 41 can be detected by the third position detector 33 .
The motor 38 is geared with the first and second sliding bars 40 and 41 (e.g., a rack and a pinion assembly) to rotate. When the motor 30 rotates in a first direction (clockwise), the first door 11 is open by the first sliding bar 40 . When the motor 38 rotates in a second direction (counterclockwise), the second door 12 can be open by the second sliding bar 41 .
The first to third position detectors 31 to 33 detect the rotation position of the motor 38 , that is, positions of the first and second sliding bars 40 and 41 . In detail, the first to third position detectors 31 to 33 can detect magnets (not shown) provided in the three protrusions 42 , 43 , and 44 to detect the rotation position of the motor 38 .
Meanwhile, when both of the two first and second doors 11 and 12 are closed, that is, when both of the two first and second doors 11 and 12 are in a waiting state, the first and second position detectors 31 and 32 detect the second and third protrusions 42 and 43 , and the third position detector 33 does not detect the third protrusion 44 .
Hereinafter, the operation of the door opening device 20 will be described with reference to FIGS. 7B to 7E .
As shown in FIGS. 7B , 7 C, and FIG. 8 , if a user grasps or pulls a handle 15 of the first door 11 in order to open the first door 11 , the motor 38 is driven with the manipulation of a second switch unit 17 . In this case, as shown in FIG. 7B , since the motor 38 rotates in the first direction (clockwise) to push the sliding bar 40 forward, the door 11 is open. Further, when the first to third position detectors 31 to 33 do not detect the first to third protrusions 42 to 44 of the first and second sliding bars 40 and 41 , the controller 30 recognizes an open state A of the first door 11 .
As shown in FIG. 7C , when the motor 38 rotates in the first direction (clockwise) so that the first position detector 31 detects the second protrusion 43 , and the second and third position detectors 32 and 33 do not detect any protrusions of the first and second sliding bars 40 and 41 , the controller 30 recognizes a maximum open state A of the first door 11 .
In addition, as shown in FIGS. 7D , 7 E, and FIG. 8 , if the user grasps or pulse a first handle 14 of the second door 12 in order to open the second door 12 , the motor 38 is driven with the manipulation of a first switch unit 16 . In this case, as shown in FIG. 7D , since the motor 38 rotates in the second direction (counterclockwise) to push the second sliding bar 41 forward, the second door 12 is open. Further, if the first and second position detectors 31 and 32 do not detect the first and second protrusions 42 and 43 , and the third position detector 33 detects the third protrusion 44 , the controller 30 recognizes the open state B of the second door 12 .
In addition, as shown in FIG. 7E , the motor 38 rotates in the second direction (counterclockwise), so that the second and third position detectors 32 and 33 detect the first and third protrusions 42 and 44 , and the first position detector 31 does not detect the second protrusion 43 of the sliding bar 40 , the controller 30 recognizes the maximum open state A of the second door 12 .
FIG. 9 is a flowchart showing an initialization operation of the door opening device 20 upon a power-on state according to the second embodiment.
As shown in FIG. 9 , if the refrigerator is powered on, the controller 30 turns on a timer 35 to set a time T of the timer to 0 (operations S 400 and S 410 ).
Then, the controller 30 determines if the time T of the timer 35 exceeds a preset time T 1 . If the time T does not exceed the preset time T 1 , the controller 30 determines if the first and second doors 11 and 12 of the refrigerator are in the waiting state. In other words, the controller 30 determines if the first and second protrusions 42 and 43 of the first sliding bar 40 are detected by the first and second position detectors 31 and 32 , and the third position detector 33 does not detect the protrusion 44 , to determine the closed state of the first and second doors 11 and 12 (operations S 420 and S 430 )
Next, if the controller 30 determines that both of the first and second doors 11 and 12 are in the waiting state when the refrigerator is powered on in operation S 430 , the controller 30 determines the operational state of the motor 38 . Accordingly, if the motor 48 is operating, the controller 30 stops the rotation of the motor 38 and terminates the initialization operation. However, if the first and second doors 11 and 12 are in the waiting state when the refrigerator is powered on, since the motor 38 has been stopped, the initialization operation is instantly terminated (operations S 450 and S 460 ).
Meanwhile, the controller 30 determines that both of the first and second doors 11 and 12 of the refrigerator are not in the waiting state in operation S 430 , the controller 30 determines if the third protrusion 44 is detected by the third position detector 33 . In other words, the controller 30 determines if the third protrusion 33 of the second sliding bar 41 is detected by the third position detector 44 .
Thereafter, the controller 30 determines that the door 12 is open if the third protrusion 44 is detected by the third position detector 33 in operation S 440 , and rotates the motor 38 in the first direction (clockwise) to move the second sliding bar 41 such that the second door 12 is closed (operation S 470 ).
Therefore, the controller 30 determines that the first door 11 is open if the third protrusion 44 is not detected by the third position detector 33 , and rotates the motor 38 in the second direction (counterclockwise) to move the first sliding bar 40 such that the first door 11 is closed in operation S 470 . In other words, the controller 30 determines that the second door 12 is open if the third protrusion 44 is detected by the third position detector 33 , and the first door 11 is open if the third protrusion 44 is not detected by the third position detector 33 according to the program stored in the memory 34 . Accordingly, the controller 30 rotates the motor 38 such that the two first and second doors 11 and 12 are regulated to be closed, that is, be in the waiting state (operation S 480 ).
If the motor 38 rotates in operations S 470 to S 480 , the controller 30 returns to operation S 420 to determine if the time T of the timer 35 exceeds the preset time T 1 . If the time T of the timer 35 does not exceed the time T 1 , the controller 30 repeats operations S 430 to S 440 . In this case, if the first and second doors 11 and 12 do not reach the waiting state until the time T of the timer 35 exceeds the time T 1 , the controller 30 stops the motor 38 , determines that the door opening device 20 is failed, and displays the failure of the door opening device 20 on the display unit 37 (operations S 490 to S 510 ).
However, if the first and second doors 11 and 12 reach the waiting state within the preset time T 1 through the above procedure, the controller 30 determines the operational state of the motor 38 and then stops the motor 38 , thereby terminating the initialization operation (operations S 450 and S 460 ).
Although few embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.
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A refrigerator equipped with a door opening device opening doors by driving a motor and a method of controlling the same. In the method of controlling the refrigerator includes a door opening device including a plurality of sliding bars selectively opening first and second doors, a motor opening the first door or the second door by moving back and forth the sliding bars in directions opposite to each other, a plurality of position detectors detecting at least one protrusion provided at one side of the sliding bar, a switch unit inputting door opening signals, and a controller controlling operation of the first door and the second door according to the door opening signals. If door opening signals used to open the first and second doors, the door opening device is controlled so that the first and second doors are easily open/closed.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to cooking utensils, supports, racks, brackets, and the like. More particularly, the present invention relates to a folding rack that supports poultry, including supports for multiple poultry wings.
[0003] 2. Description of the Related Art
[0004] Innumerable grills, racks, and the like have been developed in the past for holding food while cooking. Most such racks are relatively simple devices, and are not optimized for efficient use or storage. For example, pieces of food must be laid out flat upon an ordinary flat grill. This results in each piece taking up considerably more horizontal room or space than would be required if some means were available to hold the piece upright or on edge. A grill having such means for holding pieces of food upright while cooking would enable the cook to prepare more food on a given size grill, oven, barbecue, or the like. The articles of food are also generally more evenly exposed to the cooking heat, thus providing more even cooking of the food.
[0005] Thus, a folding rack solving the aforementioned problems is desired.
SUMMARY OF THE INVENTION
[0006] The folding rack includes a relatively flat, horizontal grill component having a series of rows of tines foldably extending therefrom. The tip of each tine is exposed. Adjacent tines define an open capture area therebetween, allowing food or other items to be placed between, or impaled upon, the tines. At least some of the tine rows are configured with stop bars to limit angular motion of the hinged tines and prevent the tines from passing substantially beyond the vertical, relative to the plane of the grill. Another tine row may be provided without such limit, to allow that row to be pivoted or hinged through 180° of travel. The grill or rack may include a series of folding legs, which may operate in the same manner as the folding tines. All of the tines in any given row and the legs at each end of the grill are interconnected to fold and extend together.
[0007] As the device is primarily oriented for use in cooking, it is preferably constructed of a material that is safe for use in cooking and coming into contact with food, e.g., stainless steel wire or rod. The material may be coated with a non-stick coating that is safe for food contact, e.g., Teflon® (polytetrafluoroethylene resin; Teflon is a registered trademark of E.I. du Pont de Nemours and Company of Wilmington, Del.).
[0008] These and other features of the present invention will become readily apparent upon further review of the following specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is an environmental, perspective view of a folding rack according to the present invention, showing its placement in a roasting pan for cooking.
[0010] FIG. 2 is a side elevation view of a folding rack according to the present invention, showing the folding of the various rows of tine racks of the device.
[0011] FIG. 3 is a detailed, partial perspective view of one corner of a folding rack according to the present invention, showing hinge and stop details for one of the tine racks and optional support leg elements.
[0012] FIG. 4A is a detailed, partial perspective view of a portion of a folding rack according to the present invention, showing a first tine rack configuration having blunt tine ends, one of the tines being broken away to show an optional coating shown disposed partially thereover.
[0013] FIG. 4B is a detailed, partial perspective view of a portion of a folding rack according to the present invention, showing a second tine rack configuration having sharpened or pointed tine ends.
[0014] FIG. 4C is a detailed, partial perspective view of a portion of a folding rack according to the present invention, showing a third tine rack configuration having bladed tine ends.
[0015] Similar reference characters denote corresponding features consistently throughout the attached drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] The present invention relates to various embodiments of a folding rack for use in cooking articles of food. The folding rack includes a series of tine rows, which may be folded downwardly adjacent the plane of the grill when not in use or extended to support articles atop the grill. Folding support legs may optionally be provided as well.
[0017] FIG. 1 of the drawings provides an environmental perspective view of a first embodiment of a folding rack 10 , shown resting upon or in a pan P and holding several food articles (e.g., chicken wings W and a chicken C) for cooking. The folding rack 10 has a flat, planar grill portion 12 formed of a series of substantially parallel grill elements 14 (e.g., steel wire or rod, etc.). At least one, and preferably several, tine row(s) 16 extend foldably from the grill portion 12 . Each tine row 16 has multiple individual tines 18 extending therefrom. Each tine row extends and folds as a unit. FIG. 1 shows two pairs of parallel tine rows 16 , the two rows 16 in each pair being spaced apart and the tines 18 in each of the rows 16 being uniformly spaced apart in order to facilitate the placement of wings W or other food articles extending between the rows 16 in each pair and supported between or upon adjacent tines 18 .
[0018] FIG. 2 is a front elevation view of the folding rack 10 , showing the configurations of the grill attachment arms 20 at the opposite ends of each of the tine rows 16 and pivotal attachment of the arms 20 to the grill 12 . Each grill attachment arm 20 has a proximal grill extension portion 22 and an opposite, distal tine portion 24 . The two portions 22 and 24 have a bend 26 formed generally medially therebetween, with the bend 26 being greater than ninety degrees, most preferably about 120°, the two arm portions 22 and 24 defining an obtuse angle therebetween.
[0019] A tine support element 28 , shown most clearly in FIG. 3 , extends laterally between or across the corresponding opposed grill attachment arms 20 of each tine row 16 , with the tines 18 extending distally from support element 28 . Thus, only the two grill attachment arms 20 of each tine row 16 attach directly to the grill 12 , with the individual tines 18 extending from the tine support element 28 , which, in turn, extends laterally across the corresponding two grill attachment arms 20 of each tine row 16 .
[0020] Each of the tine rows 16 is pivotally secured to the grill portion 12 to allow folding of the tine rows 16 when not needed. The general folding operation is illustrated in FIG. 2 of the drawings, with FIG. 3 providing a detailed view of pivotal attachment of one tine row 16 to the grill 12 , as well as the extension and retraction stops provided for the tine rows 16 . A tine row attachment pintle (or pintles) 30 extends across at least a pair of grill elements 14 substantially normal thereto. The pintle(s) 30 may comprise a single wire or short rod that extends completely across the entire width of the grill 12 , or two shorter lengths extending across the outermost grill frame peripheral member and adjacent grill element 14 , as shown in FIG. 3 .
[0021] The grill extension portion 22 of each of the two opposite grill attachment arms 20 includes a tine row pintle attachment loop 32 formed about the corresponding pintle 30 . Thus, the two grill attachment arms 20 hinge or pivot about their respective attachment pintles 30 . As the two grill attachment arms 20 are rigidly secured together by the lateral tine support element 28 , the two attachment arms 20 , tine support element 28 , and tines 18 extending therefrom all hinge or pivot together as a unit for each tine row 16 .
[0022] Pivoting of the tines 18 (and the tine portions 24 of their associated grill attachment arms 20 ) is limited to an extended position substantially normal to the plane of the grill 12 by a tine row extension stop 34 attached to the grill extension portions 22 of the two opposite grill attachment arms 20 of each tine row 16 . These tine row extension stops 34 contact the grill elements 14 and/or peripheral frame member of the grill 12 when the tines 18 are fully extended, thus stopping the tines in an orientation substantially normal to the plane of the grill 12 .
[0023] The tine rows 16 are further limited in their retraction through the plane of the grill by one or more tine row retraction stops, which extend across two or more of the parallel grill elements 14 . Depending upon the spacing of the tine rows 16 from one another, these tine row retraction stops may be the same components as the tine row attachment pintles 30 . It will be seen in FIG. 2 that the span of the grill attachment arms 20 of each tine row 16 is slightly greater than the spacing between the tine row attachment pintles 30 for adjacent tine rows. Thus, the ends of the grill attachment arms 20 will contact the adjacent attachment pintles 30 , and prevent the tine rows 16 from dropping through the plane of the grill 12 . Alternatively, separate retraction stops could be provided across adjacent grill elements 14 .
[0024] The folding rack of FIGS. 1 and 2 also has an additional central folding tine row 36 , shown erected in solid lines and folded in broken lines in FIG. 2 . The central tine row 36 includes opposite first and second attachment arms 38 , with a row of tines extending therebetween. The proximal ends of the central tine row attachment arms 38 include pintle attachment loops 40 , which wrap about a corresponding central tine row attachment pintle(s) 42 . The difference between the central tine row 36 and the other tine rows 16 is that the central tine row attachment arms 38 are straight or linear from their proximal end to their distal end in order to allow the central tine row 36 to fold completely flat against the surface or plane of the grill 12 . In this manner, none of the components of the central tine row 36 protrude from the plane of the grill 12 to any significant extent when folded against the grill 12 . This allows a larger article of food, e.g., a chicken C as shown in FIG. 1 , to be placed directly atop the grill 12 . The central tine row 36 may be prevented from passing through the plane of the grill by a central tine row retraction stop or stops 44 extending across the central tine row, which may serve as the retraction stop(s) for the adjacent tine row 16 when the central tine row 36 is retracted adjacent to the grill 12 .
[0025] The folding rack 10 may optionally be provided with folding legs 46 , as shown in FIG. 3 of the drawings. The legs 46 are preferably configured similar to the grill attachment arms 20 of the tine rows 16 , i.e., having a proximal grill extension leg portion 48 and a distal leg portion 50 with a leg bend 52 defining an obtuse angle therebetween. The attachment end of the grill extension leg portion 48 includes a leg attachment loop 54 formed therein, which secures about a leg attachment pintle or pintles 56 disposed across adjacent grill elements 14 and/or the peripheral frame member of the grill 12 .
[0026] A leg extension stop 58 is attached to each leg forming the support leg assembly pair at each end of the rack 10 . The leg extension stop 58 serves two functions: (1) connecting the two corresponding legs 46 at each end of the grill 12 so they extend and retract as a unit; and (2) contacting the grill elements 14 when the legs 46 are fully extended (as shown in FIG. 3 ) to position the distal leg end portions 50 at least generally normal to the plane of the grill 12 . The legs 46 may be prevented from retracting through the plane of the grill when folded by the attachment pintle 30 of the adjacent tine row 16 , or by a separate stop, e.g., similar to the central tine row stop 44 shown in FIG. 2 .
[0027] FIGS. 4A through 4C illustrate various modifications or embodiments of the folding rack 12 . FIG. 4A provides a detail, partial perspective view of an exemplary tine row end portion showing the distal tine portion 24 of one grill attachment arm, one tine 18 , and a portion of the corresponding tine support element 28 . In FIG. 4A , the distal tine portion 24 is broken away to show its end coated with a non-stick coating 60 , e.g., Teflon® or other suitable coating material, permanently applied thereto. Such non-stick coating may optionally be provided over the entire wire rack 10 . Alternatively, the rack 12 may be provided in bare metal, preferably a corrosion-resistant steel, or may be plated with a suitable metal (e.g., chrome, etc.).
[0028] It will also be noted that the tips 62 a of the distal tine portion 24 and tine 18 are flattened in the embodiment of FIG. 4A , as well as in the embodiments of FIGS. 1 through 3 . Such blunt or flattened ends or tips may be suitable for use when materials are not to be impaled upon the tines 18 , but rather placed upon them or wedged between them, as shown in FIG. 1 . However, it may be desirable in some circumstances to sharpen the tines 18 to permit materials (e.g., food to be cooked, etc.) to be impaled upon the tines 18 . Accordingly, FIG. 4B illustrates a distal tine portion 24 and tine 18 having conically pointed ends or tips 62 b , while FIG. 4C illustrates a distal tine portion 24 and tine 18 having bladed ends or tips 62 c . The exact shape or configuration of the tips is not critical to the folding rack 10 , except that it is preferable that the tips be sharpened in some manner if they are to be used to impale food or other articles thereon.
[0029] In conclusion, the folding rack 10 in its various embodiments is well suited for use in cooking or grilling innumerable types of food, due to its configuration for holding the food more upright than a conventional grill. This allows more articles of food to be placed upon the rack during cooking, thereby making the cooking operation more efficient and reducing the number of batches of food which must be prepared and the number of grill or oven cycles needed.
[0030] It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.
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The folding rack includes a planar grill having folding tine rows extending therefrom. At least some rows include stops extending thereacross to prevent the rows from passing substantially beyond the vertical when they are extended from their stored positions adjacent to the grill. At least one tine row may be free of such a stop, allowing that row to pivot from one side of its pivot axis to the other. The tips of the tines are exposed to allow food or other articles to be placed between or impaled upon the tines. The grill may optionally be equipped with folding legs. The rack is preferably formed of suitable food and temperature safe material, e.g., stainless steel, for use in cooking. The various components of the rack may be coated with a non-stick coating to facilitate cleanup.
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FIELD OF THE INVENTION
The field of this invention is generally plugs and packers for downhole use and more particularly packers that have a sealing element that swells and retains boost forces when subjected to pressure differentials.
BACKGROUND OF THE INVENTION
Packers and plugs are used downhole to isolate zones and to seal off part of or entire wells. There are many styles of packers on the market. Some are inflatable and others are mechanically set with a setting tool that creates relative movement to compress a sealing element into contact with a surrounding tubular. Generally, the length of such elements is reduced as the diameter is increased. Pressure is continued from the setting tool so as to build in a pressure into the sealing element when it is in contact with the surrounding tubular.
More recently, packers have been used that employ elements that respond to the surrounding well fluids and swell to form a seal. Many different materials have been disclosed as capable of having this feature and some designs have gone further to prevent swelling until the packer is close to the position where it will be set. These designs were still limited to the amount of swelling from the sealing element as far as the developed contact pressure against the surrounding tubular or wellbore. The amount of contact pressure is a factor in the ability to control the level of differential pressure. In some designs there were also issues of extrusion of the sealing element in a longitudinal direction as it swelled radially but no solutions were offered. A fairly comprehensive summation of the swelling packer art appears below:
I. References Showing a Removable Cover Over a Swelling Sleeve
1) Application US 2004/0055760 A1
FIG. 2 a shows a wrapping 110 over a swelling material 102 . Paragraph 20 reveals the material 110 can be removed mechanically by cutting or chemically by dissolving or by using heat, time or stress or other ways known in the art. Barrier 110 is described in paragraph 21 as an isolation material until activation of the underlying material is desired. Mechanical expansion of the underlying pipe is also contemplated in a variety of techniques described in paragraph 24 .
2) Application US 2004/0194971 A1
This reference discusses in paragraph 49 the use of water or alkali soluble polymeric covering so that the actuating agent can contact the elastomeric material lying below for the purpose of delaying swelling. One way to accomplish the delay is to require injection into the well of the material that will remove the covering. The delay in swelling gives time to position the tubular where needed before it is expanded. Multiple bands of swelling material are illustrated with the uppermost and lowermost acting as extrusion barriers.
3) Application US 2004/0118572 A1
In paragraph 37 of this reference it states that the protective layer 145 avoids premature swelling before the downhole destination is reached. The cover does not swell substantially when contacted by the activating agent but it is strong enough to resist tears or damage on delivery to the downhole location. When the downhole location is reached, pipe expansion breaks the covering 145 to expose swelling elastomers 140 to the activating agent. The protective layer can be Mylar or plastic.
4) U.S. Pat. No. 4,862,967
Here the packing element is an elastomer that is wrapped with an imperforate cover. The coating retards swelling until the packing element is actuated at which point the cover is “disrupted” and swelling of the underlying seal can begin in earnest, as reported in Column 7 .
5) U.S. Pat. No. 6,845,322
This patent has many embodiments. The one in FIG. 26 is foam that is retained for run in and when the proper depth is reached expansion of the tubular breaks the retainer 272 to allow the foam to swell to its original dimension.
6) Application US 2004/0020662 A1
A permeable outer layer 10 covers the swelling layer 12 and has a higher resistance to swelling than the core swelling layer 12 . Specific material choices are given in paragraphs 17 and 19 . What happens to the cover 10 during swelling is not made clear but it presumably tears and fragments of it remain in the vicinity of the swelling seal.
7) U.S. Pat. No. 3,918,523
The swelling element is covered in treated burlap to delay swelling until the desired wellbore location is reached. The coating then dissolves of the burlap allowing fluid to go through the burlap to get to the swelling element 24 which expands and bursts the cover 20 , as reported in the top of Column 8 .
8) U.S. Pat. No. 4,612,985
A seal stack to be inserted in a seal bore of a downhole tool is covered by a sleeve shearably mounted to a mandrel. The sleeve is stopped ahead of the seal bore as the seal first become unconstrained just as they are advanced into the seal bore.
II. References Showing a Swelling Material under an Impervious Sleeve
1) Application US 2005/0110217
An inflatable packer is filled with material that swells when a swelling agent is introduced to it.
2) U.S. Pat. No. 6,073,692
A packer has a fluted mandrel and is covered by a sealing element. Hardening ingredients are kept apart from each other for run in. Thereafter, the mandrel is expanded to a circular cross section and the ingredients below the outer sleeve mix and harden. Swelling does not necessarily result.
3) U.S. Pat. No. 6,834,725
FIG. 3 b shows a swelling component 230 under a sealing element 220 so that upon tubular expansion with swage 175 the plugs 210 are knocked off allowing activating fluid to reach the swelling material 230 under the cover of the sealing material 220 .
4) U.S. Pat. No. 5,048,605
A water expandable material is wrapped in overlapping Kevlar sheets. Expansion from below partially unravels the Kevlar until it contacts the borehole wall.
5) U.S. Pat. No. 5,195,583
Clay is covered in rubber and a passage leading from the annular space allows well fluid behind the rubber to let the clay swell under the rubber.
6) Japan Application 07-334115
Water is stored adjacent a swelling material and is allowed to intermingle with the swelling material under a sheath 16 .
III. References Which Show an Exposed Sealing Element that Swells on Insertion
1) U.S. Pat. No. 6,848,505
An exposed rubber sleeve swells when introduced downhole. The tubing or casing can also be expanded with a swage.
2) PCT Application WO 2004/018836 A1
A porous sleeve over a perforated pipe swells when introduced to well fluids. The base pipe is expanded downhole.
3) U.S. Pat. No. 4,137,970
A swelling material 16 around a pipe is introduced into the wellbore and swells to seal the wellbore.
4) US Application US 2004/0261990
Alternating exposed rings that respond to water or well fluids are provided for zone isolation regardless of whether the well is on production or is producing water.
5) Japan Application 03-166,459
A sandwich of slower swelling rings surrounds a faster swelling ring. The slower swelling ring swells in hours while the surrounding faster swelling rings do so in minutes.
6) Japan Application 10-235,996
Sequential swelling from rings below to rings above trapping water in between appears to be what happens from a hard to read literal English translation from Japanese.
7) U.S. Pat. No. 4,919,989 and 4,936,386
Bentonite clay rings are dropped downhole and swell to seal the annular space, in these two related patents.
8) US Application US 2005/009363 A1
Base pipe openings are plugged with a material that disintegrates under exposure to well fluids and temperatures and produces a product that removes filter cake from the screen.
9) U.S. Pat. No. 6,854,522
FIG. 10 of this patent has two materials that are allowed to mix because of tubular expansion between sealing elements that contain the combined chemicals until they set up.
10) US Application US 2005/0067170 A1
Shape memory foam is configured small for a run in dimension and then run in and allowed to assume its former shape using a temperature stimulus.
IV. Reference that Shows Power Assist Actuated Downhole to Set a Seal
1) U.S. Pat. No. 6,854,522
This patent employs downhole tubular expansion to release potential energy that sets a sleeve or inflates a bladder. It also combines setting a seal in part with tubular expansion and in part by rotation or by bringing slidably mounted elements toward each other. FIGS. 3 , 4 , 17 - 19 , 21 - 25 , 27 and 36 - 37 are illustrative of these general concepts.
The various concepts in U.S. Pat. No. 6,854,522 depend on tubular expansion to release a stored force which then sets a material to swelling. As noted in the FIG. 10 embodiment there are end seals that are driven into sealing mode by tubular expansion and keep the swelling material between them as a seal is formed triggered by the initial expansion of the tubular.
What has been lacking is a technique for automatically capturing applied differential pressures to a set element, particularly when set by swelling in reaction to exposure to well fluids, and retaining that force in the element to retain or/and boost its sealing capabilities downhole. The present invention offers various embodiments that capture boost forces from differential loading in the uphole or downhole directions and various embodiments to accomplish such capture in a single element or multiple elements on a single or multiple mandrels. Those skilled in the art will more readily appreciate the scope of the invention from a review of the description of the preferred and alternative embodiments, the drawing and the claims that appear below and define the full scope of the invention.
SUMMARY OF THE INVENTION
A packer assembly features one or more elements that preferably swell when in contact with well fluids and have a feature in them that responds to an applied load in a given direction by retaining such a boost force with a locking mechanism. A single element can have two such mechanisms that respond to applied forces from opposed directions. Friction force for adhering the element to the mandrel is enhanced with surface treatments between them that still allow the locking mechanisms to operate.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a section view showing a sealing element that is fixed on one end and has the locking feature for capturing a boost force in one direction at the opposite end and shown in the run in position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 will be used to illustrate a variety of variations of the present invention. What is illustrated in the Figure is a mandrel 10 for a packer P. Mounted to the mandrel 10 is an element 12 that preferably is of the type that swells in contact with well fluids using materials described in the patents and applications discussed above. A covering (not shown) can also be applied to the element 12 to provide a time delay to allow the packer P to be positioned close to where it needs to be set. The materials that accomplish this delay using a cover that goes away after a time exposure to well fluids and predetermined temperatures are also discussed in the patents and applications above.
In the Figure, the element assembly 12 has an uphole end 14 and a downhole end 16 . In one variation that is shown, the uphole end 14 is abutting a block 18 and is further secured to it and between itself and mandrel 10 with an adhesive or some type of bonding material 20 compatible with well materials and temperatures. Block 18 can be a ring welded to the mandrel 10 or can be attached with adhesive or threads or can be integral to the mandrel. While the element 12 can swell radially along its length, differential loading from the uphole end 14 toward the downhole end 16 will not budge the element away from block 18 due to the presence of bonding material 20 . In the embodiment of the Figure, any net downhole force from such loading will not add an additional sealing force into the element 12 because the upper end of the embodiment in the Figure is bonded and stationary, unlike the opposite end that has a ratchet feature, as will be described below. However, if there is differential loading after the element 12 swells to a sealing position the result will be that pressure applied in that direction will cause the downhole end 16 to ride toward uphole end 14 thus shortening the length of the element 12 while increasing its internal pressure. This increase in internal pressure will enhance the sealing force of the element to allow it to withstand even greater differentials going from the downhole end 16 to the uphole end 14 . To lock in that boost force that comes from loading due to increasing pressure conditions near the downhole end 16 , it is desirable to lock in such boost forces when they occur. To accomplish this, the mandrel 10 has a series of serrations or other rough surface treatment 22 adjacent downhole end 16 . The element 12 has an undercut 24 where ring 26 is secured with an adhesive or other bonding material 28 adjacent a ring 30 with an interior serrated surface 32 . Surfaces 22 and 32 ride over each other in one direction like a ratchet but lock upon relative movement in an opposed direction. Ring 30 is also bonded to element 12 with adhesive such as 28 . Rings 26 and 30 can be separate or unitary. In this version, the central section 34 is not bonded to mandrel 10 . This allows the length of the element 12 to decrease in response to a net force when the element 12 is set and compressed from an uphole directed force. Such a force results in ratcheting between surfaces 22 and 32 to lock in a greater force into the swelled element 12 against a surrounding tubular or an open hole (neither of which are shown).
Those skilled in the art will appreciate that the design shown in FIG. 1 can be inverted so that net forces in the downhole direction or toward the right in FIG. 1 will result in locking in a greater sealing force in the element 12 .
Another variation is to use two packers P mounted adjacent each other with opposed orientations for the locking device so that net forces in an uphole or downhole direction will each result in capturing a greater sealing force in the element 12 . Alternatively, a single mandrel 10 can house two elements of the type shown in FIG. 1 except that they are in mirror image orientation to allow capturing additional sealing force in the element 12 regardless of the direction of the net applied force. In yet another alternative, the assembly shown in undercut 24 can be disposed on opposed ends of the same element with a binder such as 20 being disposed only in the middle portion 34 . In that manner, a net force in either direction will cause a ratcheting action that retains a greater sealing force in the element 12 .
While a ratchet based system for locking in additional sealing force has been illustrated other mechanisms that permit unidirectional compression of the element from applied differential pressure loads on a set element 12 downhole are well within the scope of the invention.
Referring again to FIG. 1 an additional feature can be added to deal with the issue of relative movement during delivery to the packer P to the desired location for setting. Portions of the mandrel 10 can receive a roughening surface treatment in the form of grooves or adhered particles that will enhance the grip on element 12 . Of course, the location of such treatment of the mandrel 10 need to be placed in locations where longitudinal compression of the element 12 from pressure loading will not be impaired. For example, in the embodiment literally shown in FIG. 1 the block 18 will adequately resist shifting of the element 12 during run in. The middle section 34 will need to permit sliding to allow the ratcheting movement between teeth 22 and 32 . To prevent premature ratcheting during run in, a ring 36 can retain end 16 during run in and can be made of a material that dissolves or goes away over time to let the ratcheting or other pressure enhancing device hold in the greater sealing force from pressure loading on the set element 12 . This can be in the form of a coated threaded ring where the coating only dissolves after a time exposure at a given temperature. After that the well fluids attack the ring to the point of failure and the swelling of the element 12 can begin to set the packer P. Alternatively, the swelling of the element 12 can defeat the retainer 36 as could simply swaging the mandrel 10 .
However, if the version shown in FIG. 1 is revised so what is depicted at end 16 is also at end 14 in a mirror image, then it would make sense to surface treat the mandrel 10 in the middle section 34 as that section would not be moving during normal operation of the packer P. The surface treatment on the mandrel 10 can also act to hold the boost force from pressure loading that is anticipated once the packer P goes in service. Alternatively the element 12 itself can have a surface treatment where it contacts the mandrel 10 or both can be treated in the area of contact. Surface treatment on the mandrel can be multiple grooves, for example.
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:
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A packer assembly features one or more elements that preferably swell when in contact with well fluids and have a feature in them that responds to an applied load in a given direction by retaining such a boost force with a locking mechanism. A single element can have two such mechanisms that respond to applied forces from opposed directions. Friction force for adhering the element to the mandrel is enhanced with surface treatments between them that still allow the locking mechanisms to operate.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional Ser. No. 60/483,699, filed Jun. 30, 2003.
BACKGROUND OF THE INVENTION
[0002] This invention concerns collapsible portable supports as used in camping for chairs, tables, etc. The collapsible design allows these items to be brought along on camping trips since the amount of space required in a vehicle is greatly reduced.
[0003] Camping usually involves cooking and washing of utensils, dishes, etc. Heretofore, washing the dishes has been quite inconvenient when, with the water stored in an often collapsible heavy jug and rinsing and washing in separate dishpan being quite awkward. Dispensing water from a large jug is also itself inconvenient.
[0004] It is an object of the present invention to provide a collapsible two tier support for convenient washing of dishes in a pan on a lower support and dispensing of water from a water jug on an adjacent upper support.
SUMMARY OF THE INVENTION
[0005] The above object and others which will be understood upon a reading of the following specification and claims are achieved by a two tier collapsible support. The support is formed by four elongated uprights arranged vertically spaced apart and parallel to each other in a rectangle with a fabric panel attached at their upper ends to provide a first generally planar support surface as for holding a water jug. The four uprights have pivoted cross brace sets interconnected to respective pairs of adjacent uprights to be braced in their spaced apart position.
[0006] Four sets of pivoted cross braces, each connected to an adjacent pair of uprights have brace members having a pivotal connection together with the bottom ends of the uprights to connector pieces. The upper ends of the brace members are connected to connector pieces slidable on a respective upright at an intermediate region thereof.
[0007] A second fabric rectangular panel support is connected on one side of one pan of the uprights by an additional three sets of pivoted cross braces, arranged in a rectangle together with one of the cross brace sets interconnecting the uprights. The second fabric panel provides a second panel horizontal support surface at a lower height than the first horizontal support surface and immediately adjacent thereto.
[0008] The entire assemblage can be collapsed laterally to bring all four uprights and cross brace members together by pivoting of the cross brace members.
DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a pictorial view of a two tier collapsible support according to the present invention, with supported items shown in phantom lines.
[0010] FIG. 2 is a side elevational view of the two tier collapsible support shown in FIG. 1 .
[0011] FIG. 3 is a front view of the two tier collapsible support shown in FIGS. 1 and 2 .
[0012] FIG. 4 is a pictorial collapsed view of the collapsible support shown in FIGS. 1 - 3 .
[0013] FIG. 5 is an enlarged pictorial view of one of the short upright cross bracing connector pieces incorporated in the two tier support shown in FIGS. 1-4 , with fragmentary portions of the connected upright and cross bracing member.
[0014] FIG. 6 is an enlarged pictorial view of the rear upright connector-cross bracing connector pieces, with a fragmentary portion of a rear upright and a cross bracing member.
[0015] FIG. 7 is an enlarged pictorial view of a connector piece connecting the forward pair of uprights to members of three adjacent cross bracing sets, with a fragmentary view of the adjacent portions of the upright and cross brace set members.
[0016] FIG. 8 is an enlarged pictorial view of a sliding connector piece fixed to a cross bracing member and slidable on an upright, portions of both shown in fragmentary form.
[0017] FIG. 9 is a fragmentary pictorial view of one corner of fabric panel forming an upper planar support and adjacent portion of an upright.
[0018] FIG. 10 is a fragmentary pictorial view of an inside corner of a fabric panel forming a lower horizontal support and adjacent portions of an upright and cross bracing members.
DETAILED DESCRIPTION
[0019] In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims.
[0020] Referring to the drawings, and particularly FIGS. 1-4 , a collapsible two tier support 10 according to the invention includes an upper generally planar support surface 12 provided by a rectangular durable (nylon, etc.) fabric panel 14 attached at each corner to an upper end of a respective elongated upright 16 .
[0021] A second lower generally planar support surface 18 is provided adjacent and below the upper support surface 16 by a rectangular fabric panel 20 attached to two forward corners to the top ends of two cross brace members 22 , and at two rear corners to two of the uprights 16 A, 16 B at an intermediate height as well as the upper ends of the cross brace set members interconnecting the uprights 16 A, 16 B.
[0022] A mesh material storage bag 24 can be attached to one side of the lower fabric panel 20 .
[0023] This arrangement provides a planar support for a water jug 26 on the upper support surface 12 above a dishpan 28 on the lower support surface 20 for convenient dishwashing.
[0024] Each pair of the uprights 16 are interconnected by one of four cross brace sets 30 A, B, C, D, respectively mounted between each adjacent pair of uprights 16 by bottom connector pieces 32 A, B and 34 A, B and intermediate connector pieces which comprise inverted connector pieces 32 C, D and 34 C, D.
[0025] Such connector pieces are commercially available and used in other types of collapsible furniture.
[0026] Connector pieces 32 A-D ( FIG. 6 ) comprised molded plastic bodies having a vertical hole 38 able to receive the lower end of an upright 16 (secured with a screw, not shown) and walls 40 , 42 to which the lower ends of two cross brace members 44 are pivotally attached.
[0027] Connector pieces 32 C, D ( FIG. 8 ) are the same as connector pieces 32 A, B but are inverted to receive the upper ends of cross brace members 44 . The uprights 16 C, D pass completely through holes 38 and are slidable thereon.
[0028] Connector pieces 34 A, B ( FIG. 7 ) are also molded plastic bodies which have three vertical walls 46 , 48 , 50 to which are pivotally attached to the lower ends of three cross brace members 44 , and a hole 52 receiving a lower end of an upright 16 A or 16 B.
[0029] Connector pieces 34 C, D are the same but are inverted and slidable on the uprights 16 A, B along an intermediate section thereof.
[0030] There are three forward cross brace sets 30 E, F, G arranged in a rectangle with the forward cross brace set 30 D between uprights 16 C, D.
[0031] The lower ends of formed cross brace members 44 of the cross brace sets are pivotally mounted to connector pieces 32 E, F ( FIG. 5 ) configured the same as connector pieces 32 A-D.
[0032] The lower ends of the rear cross brace members 44 of cross brace sets 30 E, G are secured in connector pieces 34 A, B.
[0033] The upper ends of the forward cross brace members 44 of cross brace sets 30 E, F, G are pivoted to inverted connector pieces 32 G, H.
[0034] The rear upper ends of cross braces 30 E, G are pivotally mounted to connector pieces 34 D, C.
[0035] The fabric panels 14 , 20 each have grommets at their corners ( FIGS. 9, 10 ). The upper fabric panel 20 is secured with headed plastic pieces 58 secured with screws (not shown) passing up through associated connector pieces 32 I, J.
[0036] The entire assemblage can be collapsed by lifting, the same and pushing the uprights 16 and cross braces 30 E, F, G together in both orthogonal horizontal directions, to the greatly compacted condition shown in FIG. 4 .
[0037] This allows for convenient storage and transport to provide a practical use in camping expeditions.
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A collapsible two tier support as for use in camping dishwashing is formed by four uprights connected by pivoted cross brace sets and having a fabric panel defining on upper support connected to the tops. Additional cross brace sets support a second fabric panel at a lower level adjacent the uprights. The entire assemblage is collapsible by pivoting action of the cross brace members.
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CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application is a U.S. National Stage application of International Application No. PCT/FI02/00744, filed Sep. 19, 2002, and claims priority on Finnish Application No. 20011848, Filed Sep. 19, 2001.
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
[0002] Not applicable.
BACKGROUND OF THE INVENTION
[0003] The invention relates to a method for producing fibre pulp and fuel out of municipal waste. In the method the waste is pre-treated and the pre-treated waste is pulped in order to fiberize the paper contained in it in water. Two material flows are removed from the pulper, the first of which mainly contains fibre suspension and the second mainly contains indecomposable reject. The fibres contained in the first material flow are recovered and converted into fibre pulp, and the reject contained in the second material flow is correspondingly recovered and converted into fuel. The method according to the invention also helps in recovering other waste components, such as metals, from dry waste in a clean enough state for efficient recycling.
[0004] The invention also relates to a method for producing fibre pulp out of waste paper.
[0005] The invention also relates to apparatus for carrying out the above-mentioned methods.
[0006] Domestic, industrial and commercial waste flows contain a lot of usable material the recycling of which would be sensible and environmentally friendly if it could be carried out in an economically profitable fashion. Traditional alternatives of waste disposal and processing have been transportation of waste to a landfill, incineration in mass incineration plants and recycling of recyclable materials. Traditional recycling methods require the waste to be carefully separated at source and the different waste components to be collected separately. Source separation is, however, always to some extent imperfect and due to this the amount of mixed waste is significant now and will also be significant in the future.
[0007] Lately, there has been an increase in the popularity of waste energy recovery by burning quality graded recycled fuel (REF, RDF) converted from waste either in traditional boilers additionally to some other fuel or as main fuel in incineration plants especially designed for recycled fuels. Compared to a traditional mass incineration plant of mixed waste this provides lower costs and better efficiency of electricity and heat production. Waste best suited for energy recovery includes industrial and commercial packaging, paper and plastics waste and construction waste, which may together make up as much as 70-80% of the amount of waste originating from these sources and which amount is usually transported to a landfill. Domestic dry waste can also be used in energy production as long as e.g. metals, glass and organic waste have first been separated from it.
[0008] The refining phases of recycled fuel typically include removal of oversized objects, crushing of waste, separation of metals and removal of sand and stones. The finished recycled fuel contains mainly plastics, wood, paper and textiles. The amount of incombustible impurities in the fuel may be for example of the order of about 5%, depending on the sorting process. Recycled fuel is most advantageously produced out of the energy fraction separated at source and collected separately, in which case the finished fuel is called REF fuel (recovered fuel). Recycled fuel can also be produced out of unsorted mixed waste by means of mechanical treatment processes, in which case the finished product is called RDF fuel (refuse-derived fuel). The treatment of mixed waste requires more sorting phases than the treatment of dry waste separated at source. Heavy material, such as food remains can be efficiently separated from the fraction intended for incineration, for example in gravimetric (i.e. based on the size and density of the particles) sorting phases. The composition of finished RDF fuel resembles that of REF fuel to a great extent, but the proportion of impurities in it may be a bit bigger than in the REF fuel, for example of the order of about 8%.
[0009] Patent publications describe many different methods for recovering paper fibres and/or combustible material suitable for use as recycled fuel from waste and particularly from municipal waste. None of the known methods has, however, been very popular due to disadvantages commonly related to them.
[0010] U.S. Pat. Nos. 4,026,678; 4,049,391 and 5,009,672 describe methods for producing recycled fuel out of municipal waste.
[0011] Publication FI 54936 describes a method and an apparatus for recovering usable material from municipal waste. A mixture of waste and water is agitated intensively by means of mechanical shearing forces, as a consequence of which the refuse particles become smaller and the paper contained in the refuse is fiberized. Non-fiberized material and fibrous sludge, containing, in addition to fibres, a large amount of impurities, are removed from the wet disintegration vessel. Impurities are extracted from the fibre-containing sludge by means of centrifugal cleaning and screening. The rejects from the cleaning phases are passed to incineration, composted or converted into animal feed or into hardboard. The rather similar particle size and specific gravity of paper fibres and of some other components contained in municipal waste has proven to be problematic in view of fibre recovery. To ensure a good enough quality in the fibre pulp recovered the amount of reject must be kept at a high level in the centrifugal cleaning and screening phases. As a consequence, over 25-60% of the fibre originally fed into the system has to be rejected.
[0012] Publication U.S. Pat. No. 5,100,066 describes a method with which e.g. fuel and paper fibre are produced out of municipal waste. The waste is pre-treated and a light fraction containing paper, textiles and plastics is separated from it, which light fraction is washed and pulped in order to fiberize the paper contained in it in water. The sludge produced in pulping is screened to separate the fibres from the indecomposable reject, which is passed into fuel production. The fibre suspension is pressed dry and the paper fibres are delivered to the paper mill. Waste waters from screening and fibre pulp pressing are purified and returned to the pulper. In this process fibre recovery also remains poor, since fibres are lost both at the washer preceding the pulper and on the screen following pulping, from which screen some of the fibres are removed with the reject flow to incineration. The quality of the recovered fibre pulp is poor, because it is not sorted in any way after the screening following pulping and before pressing and delivery to the paper mill. Also, the quality of the fuel produced in the process is poor, as it is composed of mixed refuse material.
[0013] A problem associated with the recovery of municipal waste is the large microbe content of the waste, which content still tends to grow during the processing of the waste. This may lead to problems in the different phases of the process and the problems may also have repercussions in the fibre pulp produced out of the waste. A high level of microbial activity may also cause problems with e.g. hygiene and odors as well as lead to fibre loss and poor quality of fibre. Some known arrangements have tried to avoid problems caused by microbes by separating fibres from other waste components in a dry process from beginning to end. Wet processing has, however, its advantages, such as the purity and good quality of the fibre pulp and fuel produced.
SUMMARY OF THE INVENTION
[0014] An object of the invention is to reduce problems related to the recovery and recycling of the recyclable fractions of municipal waste.
[0015] An object is especially to provide a process by means of which it is possible to simultaneously produce, out of waste, microbiologically pure, good-quality fibre pulp and homogenous fuel with a good heating value.
[0016] A further objective of the invention is to provide a process for producing fibre pulp which meets the quality requirements set for fibre products that come into contact with foods, such as corrugated cardboard cases meant for packing fruit and vegetables.
[0017] For the sake of the purity of the fibre pulp it is essential that the retention time in the process is kept so short as to prevent the microbes from reproducing to a detrimental extent. In the method according to the invention the process tanks are designed so that the retention time of the process is less than 12 hours, preferably less than 6 hours and most preferably less than 2 hours. The purity of the process can also be enhanced by increasing the amount of water being passed to water treatment from the process. In such a case filtrates and contaminated waters of the process are circulated back into use through biological treatment, whereby the water circulating through the biological treatment rinses the process and washes nutrients and microbes out of it. In the method according to the invention the amount of water circulated through the biological treatment is 5-50 m 3 , advantageously 10-30 m 3 , per fibre ton recovered.
[0018] The reproduction of microbes in their growth phase can be illustrated simply with the following equation:
dC/dt=r C (1)
[0019] which leads to the following:
C t =C o e r t (2)
[0020] In these equations:
[0021] dC/dt=increase in the amount of microbes in a time unit,
[0022] t=retention time in the process,
[0023] C o =amount of microbes at the starting point,
[0024] C=amount of microbes in the process at the point of observation,
[0025] C t =amount of microbes in the process after the lapse of time t,
[0026] r=reaction rate constant (growth rate constant) dependent on the conditions.
[0027] For the reaction rate constant r the following equation applies:
r= 1 /k (3)
[0028] where k=average division time of microbes in the conditions in question.
[0029] The division time of most microbes that can be found in the processes of the paper industry is between a half an hour and a couple of hours depending, for example, on the acidity and temperature of the process as well as on the nutrients contained by the raw material. In practice, using biocides can retard the reproduction of microbes and the problems caused by them.
[0030] The exponential growth of the microbe content can be illustrated with an example. If the number of microbes contained in the raw material is C o , the division time of the microbes being one hour, after two hours the number of microbes is C o 2 and after six hours C o 6 . Correspondingly, after 24 hours the number is C o 24 , provided that the nutrients present in the waters do not constrain the bacterial growth.
[0031] In the existing recycled fibre processes the retention times are, in practice, more than 24 hours, even several days. The retention in the process and intermediate tanks of the pulp department can be several hours. In the pulp tower, for example, it is often 8-12 hours, and the water tower of the pulp department is usually of a similar size and the clear filtrate tower likewise. For the sake of the controllability of the process shorter retention times have not really been accepted in traditional processes. In order to be able to control the heavy slime build-up and paper machine problems caused by microbial growth, the water circulation of the machines is dosed with biocides against microbes, with which the amount of bacteria is in most cases constrained to a level of 10 5 -10 7 colonies/ml.
[0032] It can be concluded from the simple calculation presented above that by reducing the retention time of the process from 24 hours to 6 hours the amount of bacteria produced by growth can be decreased at best by an order of magnitude of C o 18 meaning that the bacteria content of the product is reduced to a billionth of a billionth. In practice, the difference is not quite as significant due to the use of biocides and a division time which is an hour longer, on average. It is clear, however, that by means of the process according to the invention, in which process the retention time is only a few hours, both the need to use biocides and the amount of bacteria carried with the product flow are very decisively reduced compared to the traditional process, in which the retention time is long.
[0033] A short retention time can be brought about by keeping the total liquid volume of the process small enough. This objective can be illustrated by means of an equation depicting the retention time t:
t=V p /( F K +F R +F B ) (4)
[0034] where
[0035] V p =total liquid volume of the process equipment,
[0036] F K =volume flow discharging together with the fibres,
[0037] F R =volume flow discharging together with the reject, and
[0038] F B =volume flow passed to a biological treatment plant.
[0039] The equation illustrates well the average retention time of waters within the balance boundaries of the factory. The real retention time differs from this slightly since the water exchange rate varies in different tanks.
[0040] Said total liquid volume of the process equipment comprises the liquid volume of all pulp, water and reject tanks, the liquid volume including pulps and waters. If, for example, the reject and pulp tanks are full, the water reservoir is typically empty and vice versa. What is meant is the volume in real process usage and not the calculated volume of all the tanks added together. This is an essential piece of information in view of the reproduction of the bacteria suspended in the liquid phase. With respect to bacterial growth it is also essential that, when designing the tanks and piping, blind angles, in which the microbes are able to reproduce freely, be avoided.
[0041] The retention time can be shortened, for example by minimizing the water volumes of the process and by recycling most of the water contaminated in the process back into use through the biological treatment.
[0042] In traditional arrangements attempts have been made to minimize the amount of water passed to waste water treatment, and in most simple recycled paper mills this amount is 3-5 m 3 /t. In cases where the water circulation has been closed by connecting the biological treatment to it, the amount of water circulating through it is of this order of magnitude.
[0043] In the method according to the invention the amount of water is not minimized, but instead, the biological treatment is part of the purity control of the process. A sufficient amount of water is taken into the biological treatment from the most contaminated phases of the process, and circulating the water through it reduces the growth of microbes in the process. The majority of the microbes coming into the biological treatment with the water are removed in the treatment and in the separation/clarification equipment, which is an essential part of it. The water returning to the process from the biological treatment can also be sterilized by using methods known as such, like UV-light, chlorination or ozonization. By means of sterilization biological activity can be done away with either completely or, if needed, only partly. Thus, the water circulation running through the biological treatment plant rinses and cleans the whole recovery process by delivering biological material into a cleaning plant, where it is removed from the water circulation, and thus reduces the biological activity in the fibre pulp produced. In order to achieve a good end result at least 5 m 3 and not more than 50 m 3 , advantageously 10-30 m 3 , of water per fibre ton produced by the recovery plant should be passed to the biological treatment. Using more water than this in the circulation does not essentially decrease the level of the biological oxygen demand (BOD) of the process water. Instead, excessive increasing of the circulation adds losses.
[0044] The growth rate of microbes depends, among other things, on the temperature and pH and on the amount of nutrients, such as phosphor, nitrogen and BOD. The amount of nutrients in the process is reduced when a major part of the water used in the process is circulated through biological treatment. Thanks to efficient water treatment and short retention times the pH of pulping rises to over 7.5, whereas it normally is below 7. The biological treatment efficiently removes organic acids from the waters by breaking them down into carbon dioxide and oxygen. At the same time some of the acids is replaced by bicarbonate ions. As a consequence, the pH of water settles between 7.0-8.5 without using chemicals. A high pH also makes the calcium carbonate, present in the paper as filler material, dissolve to a lesser extent, thereby improving yield and reducing the amount of waste.
[0045] The purity and hygiene level of the pulp produced out of waste fibres can be further enhanced by dispersing, whereby the pulp is heated to a temperature of about 100° C., up to 130° C., if necessary, and is defibrated at a consistency of about 30-40%, whereby the stickies present in the pulp are broken down. The retention time of pulp in dispersing is usually only 5-20 seconds. By increasing the retention time of pulp at a high temperature and consistency it is possible to further weaken the living conditions of microbes, whereby pure and sterile pulp is produced. In the method according to the invention dispersing is followed by hot storage, the duration of which may be 2-120 minutes. The minimum duration of hot storage is selected, depending on the temperature, so that the sum of temperature determined by the foodstuffs legislation for the sterilization of foods is reached.
[0046] A similar thermal treatment of pulp can also be carried out in connection with the drying of product pulp to be baled. The drying can be carried out by means of hot air, flue gas or in a steam atmosphere. The steam dryer can be a construction that passes the pulp pneumatically through heat exchangers, in which construction the retention time is typically 0.2-5 minutes, or a fluidised-bed dryer or a drum dryer, in which the retention time in superheated steam may be several tens of minutes.
[0047] Alternatively, the sterilization of pulp can also be carried out by means of bleaching by selecting such bleaching conditions, chemicals and retentions that the product is sterilized.
[0048] The ash content of fibre pulp produced out of waste fibres can be influenced by adjusting the recovery degree of ash in connection with the washing of the pulp. A washer suited for controlling the ash level is, for example, a GapWasher™ manufactured by Metso Paper, Inc. The filtrate from the washer is passed to microflotation or microfiltration, from where the ash is taken out of the process together with the sludge. The ash can also be partly or completely returned to the process depending on the properties of the raw material and the requirements of the product.
[0049] The use of recycled products made of waste fibres in the packaging of food products is limited by strict purity requirements. By means of the operations presented above it is possible to achieve, in the end product, a purity level at which board made of recycled fibre meets the requirements set for products used in connection with foods.
[0050] When pulping pre-treated municipal waste two material flows are separated from each other, the first of which is mainly composed of the water suspension of fibres and the second mainly of reject which was not decomposed during pulping. The separation into two material flows taking place in connection with the pulper is, of course, imperfect. Indeed, an additional characteristic of the invention is the recovery of fibres from the reject-containing material flow. This is carried out by washing the reject with circulation water from which the fibres have been recovered, and by passing part of the fibre-containing wash waters and the fibres recovered from the circulation water to be mixed with the fibre-containing material flow. In this way it is not only possible to increase the fibre recovery of the process, but also to enhance the heating value of the fuel produced out of the reject, since the heating value of fibres is, as is well known, significantly lower than that of, for example, plastic, which makes up the majority of the reject leaving the pulper.
[0051] The quality and purity of the fuel produced out of reject can also be enhanced by removing PVC plastics from it e.g. by using near infrared technology and the aluminium foils, for example, by means of eddy-current technology. The result is a fuel the chlorine and aluminium content of which are so low that it can safely be burned in traditional boilers. The sodium chloride contained in the waste is dissolved in water in connection with pulping, which helps in achieving low chlorine content. The heating value of the plastic-containing fuel produced with the method according to the invention is 20-40 MJ/kg, whereas the heating value of, for example, fuel produced out of domestic waste is less than 10 MJ/kg and the heating value of pure wood is 17-18 MJ/kg.
[0052] The invention will now be described in more detail with reference to the figures of the accompanying drawings, to the details of which the invention is, however, by no means intended to be narrowly confined.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] [0053]FIG. 1 shows fractionation of waste into different fractions in the various phases of the treatment.
[0054] [0054]FIG. 2 shows pulping of waste and the following process phases in the manufacture of fibre pulp and fuel.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0055] [0055]FIG. 1 schematically shows a process for producing fibre pulp and fuel, in which industrial, commercial or domestic energy waste separated at source and mainly composed of wood, plastics, paper and board and other combustible substances, is used as a raw material. Mixed waste may alternatively be used as a raw material, in which case the removal of organic waste requires more effort.
[0056] The waste material is passed from an intermediate storage 40 to crushing devices 41 , where it is broken down into pieces of the size suited for further treatment. After the crushers 41 ferrous metals are removed from the waste proceeding on the belt by means of a magnetic separator 42 . The waste material is passed onto a star screen 43 , where a light fraction containing paper and plastics is separated from it by means of air flow (suction or blowing). A fraction containing large and heavy particles is left on the screen 43 , which fraction contains, for example, wood, heavy plastics and metals. Fines and organic waste discharge through the slots of the screen 43 .
[0057] The light fraction separated from the waste with the star screen is passed onto a wind sieve 44 , where objects with heavy specific weight are separated from it by means of air flow and gravity, which objects are passed to be mixed with the heavy waste fraction leaving the star screen 43 . The pure light fraction is passed to a pulping station 45 .
[0058] At the pulping station 45 the waste is diluted with water and it is agitated intensively, whereby the paper and board present in it are fiberized in water. Debris particles are removed from the fibre-containing sludge and it is passed to fibre processing 47 . Reject, containing among other things plastics and aluminium foils, which was not decomposed during pulping, is passed to reject processing 48 , where aluminium is separated from it with an eddy-current separator and PVC plastics with a near infrared separator. These separation phases produce a plastics fraction rich in polyethylene and polypropylene plastics, which fraction is well suited to be used as fuel or as a raw material for plastic oil. The aluminium can be reused and the PVC plastics can be used as mixed fuel in energy production, whereby chlorine emissions at the cleaning devices following the boiler are prevented.
[0059] At the pulping station 45 fibre-containing rejects are produced, which can be used, e.g. as fuel. The filtrates and contaminated waters of the pulping station 45 are passed to purifying equipment 51 —the “kidney” of the process—and from there further back to the process. The kidney includes a biological treatment plant and the needed number of other water purifiers.
[0060] The heavy waste fraction from the star screen 43 is passed to a metal separation 46 , where metals are separated from it, for example by means of a magnetic separator, an eddy-current separator based on the inductivity of metals and/or a vibrating screen. After the removal of metals the waste is passed to a water bath separator 52 , where heavy substances, such as glass and stones, but also fine substances like sludge and organic waste are separated from it by means of clarification. From the water bath separator 52 the waste is passed to a second wind sieve 53 of the process, where, by means of an air flow, wood is separated from other waste, which at this point comprises mainly plastics. Plastics waste can be recovered as such or it can be passed to the separation phases 48 of aluminium and PVC together with the indecomposable reject from pulping 45 .
[0061] Contaminated wood containing wood preservatives or other contaminants can further be separated from the wood fraction recovered from the wind sieve 53 by means of an X-ray device 54 or another known separation method. After this, the contaminated wood can be incinerated, for example in a fluidised-bed boiler having flue gas purification equipment required by the EU Waste Incineration Directive. Pure wood can be used as a raw material for chipboard or as fuel.
[0062] From the process shown in FIG. 1 a pure fibre fraction and different wood, plastics and metal fractions are recovered, which may be reused either as a raw material or as fuel. A further alternative is to provide, between the wind sieve 44 and the pulping station 45 , equipment for separating different paper fractions from each other on the basis of color, whereby brown and white paper can be passed to different pulping lines and two different pulps can be produced out of the waste.
[0063] All the waste pre-treatment phases before pulping 45 and the water bath separator 52 are carried out as a dry process without added water. Due to the specific quality of the raw material the devices used in crushing and fractioning tend to get dirty, which means that their operating efficiency is diminished. According to a further characteristic of the invention certain process devices, such as the crushers 41 and the star screen 43 are equipped with wash water sprays, with which said process devices can be cleaned from the dirt periodically or whenever necessary. Circulation water, for example mechanically purified water from the water bath separator 52 , is used for washing. The wash water may also be used for decreasing the fire risk and for preventing dusting. The possibility of using circulation water in the pre-treatment process in the way illustrated above significantly improves the reliability and occupational safety of the waste treatment plant.
[0064] [0064]FIG. 2 shows in more detail the process phases associated with the pulping of pre-treated waste and with the recovery of fibres and reject at the pulping station 45 of FIG. 1 as well as the purification circulation of the waters used in the recovery process.
[0065] In a pulper 11 pre-treated dry waste 10 is diluted by means of circulation water into a mixture, the consistency of which is about 5-20%. The mixture is agitated intensively, whereby the paper and board material present in the waste is fiberized in water. The fibre suspension is passed out of the pulper 11 through a fixed screen plate in the pulper, the diameter of the holes of said screen plate advantageously being about 5-20 mm. A second material flow containing fibres and water, but also material that is not decomposed in pulping i.e. reject (e.g. plastics, wood and textiles) is removed from the pulper 11 by means of a feed screw 12 . Large, heavy particles (stones, sand, glass, etc.) sink to the lowest part of the pulper, from where they are removed by means of a separate debris trap (not shown).
[0066] The fibre suspension is first passed onto a coarse screen 20 , which is advantageously a rotary drum screen, the diameter of whose holes is advantageously in a range of 1.6-3.0 mm. The pulper may alternatively be equipped with a rotor unit according to FI patent 82493, in which unit coarse separation of the pulp is carried out at the same time. On the coarse screen 20 , e.g. plastics, slivers and other big contaminants are removed from the fibre suspension and are passed to be mixed with the reject flow discharging from the pulper 11 . The accept from the coarse screening is passed to hydrocyclones 21 and further to fine separation 22 . The reject from the fine separation 22 is passed through a press 29 and is thus converted into fuel. The separated pulp is washed with a washer 23 , which is advantageously a GapWasher™ washer. With this washer 23 inorganic material (ash) can be washed out of the pulp, which inorganic material is further removed from the filtrate of the washer by means of microflotation. In addition, the washer thickens the pulp to a consistency of 8-12%. Part of the wash filtrate is recycled through fibre recovery 33 to serve as dilution water in the process phases before washing and part is passed to be purified in a biological treatment plant 30 .
[0067] After the washer 23 the pulp is thickened by means of a screw press 24 to a dry solids content of about 30-40% and passed to dispersing 25 . The dispersing is carried out at a temperature of about 100-130° C. After the dispersing 25 the pulp is transported into a storage tank 26 , where the temperature and consistency of the pulp are maintained substantially on the same level as in the dispersing 25 . The duration of hot storage is, depending on the temperature, at least 2 minutes and not more than 120 minutes. Prolonged storage at a raised temperature and at a high consistency sterilizes the product and ensures that the microbiological requirements for the product are met.
[0068] Indecomposable material i.e. reject, mainly comprising fibres, plastics, wood, textile and other relatively light material, is continuously removed from the pulper 11 with the screw conveyor 12 . The reject discharging from the pulper 11 is washed with wash water sprays as it moves along the screw conveyor 12 and the washing is continued in a reject washing drum 13 . The fibre-containing water gathered in the water reservoir of the washing drum 13 is circulated through a purifying device 17 back into use. The purifying device 17 is equipped with two screening surfaces, of which the first one in the flow direction is meant for coarse screening (separation of debris particles and slivers) and the second one for fibre recovery. The water cleaned from fibres with the purifying device 17 is returned back to the process, where it can be passed, for example, to serve as wash water in the washing sprays of the screw conveyor 12 and into the pulper 11 or to serve as dilution water in coarse screening 20 . The fibres recovered with the purifying device 17 and the fibre-containing wash water coming from the screw conveyor 12 are passed to be mixed with the fibre suspension discharging from the pulper 11 .
[0069] After the washing drum 13 water is removed from the reject by pressing it as dry as possible, to a dry solids content of about 50-70%, by means of a screw press 28 . After this, the reject is passed to further treatment, where it is converted into fuel or into a form suited for recycling the material. The further treatment phases may include, for example, crushing or grinding of the reject and further fractionation for producing various fuel or recyclable fractions. The waste fuel produced in the way illustrated above is of a higher purity and quality compared to normal recycled fuel produced in a dry process, because organic material with a low heating value and incombustible inorganic material have been removed from it in connection with the wet treatment.
[0070] 5-50 m 3 , advantageously 10-30 m 3 , per fibre ton produced from filtrates and other dirty waters generated in the processing of waste are passed through the fibre recovery 33 to be purified in the biological treatment plant 30 . Before the biological treatment fibres, fines and ash can be recovered, for example by means of a screen and by flotation. By combining the techniques it is possible to adjust the quality of the product to a uniform level to meet the requirements. This can be influenced by returning the fibres from the screen back to the process and by taking part or all of the ash-solids mixture separated in microflotation back into production. In microflotation it is possible to affect the separation ratios between ash and other fines by changing the running parameters. After the biological treatment 30 the purified water is returned to the process and the excess is passed to a wastewater treatment plant. If particularly pure water is needed, part of the biologically treated water can still be treated with ultra- and/or nanofiltration. The water or part of the water to be returned to the process can also be sterilized, and in this way living biomass can be prevented from returning to the fibre recovery line.
[0071] Thanks to the biological treatment of circulation water the biological oxygen demand (BOD) of the process can be brought to the same level as in a traditional open water circulation system. As a consequence the pH of the process rises to a range of 7.5-8.5 and the biological activity in the water circulation diminishes. The activity of anaerobic bacteria is essentially reduced and odor nuisances also diminish.
[0072] An object of the invention is that the waste material passes rapidly through the treatment process, meaning that there is not enough time for the microbes to reproduce significantly during the process. The exponential effect of the retention time t on the growth of microbes C/dt is illustrated by the equation presented above (2):
C t =C o e r t
[0073] To decrease the retention time the liquid volume V P of the process is minimized and the amount of water F B passed from the process to water treatment is increased beyond the traditional amount. The retention time t is defined by the equation presented above (4):
t=V P /( F K +F R +F B )
[0074] The liquid volume VP of the process means the amount of liquid circulating in the liquid circulation, outlined in FIG. 2 with dashed lines, between the pulper 11 , fibre press 24 and reject press 28 . In the example case the total volume is considered to include the pulper 11 , the devices 20 , 21 , 22 , 23 , 24 , 29 and 33 used in fibre recovery, the devices 12 , 13 , 17 and 28 used in reject recovery and the pipings connecting them. F K is the volume flow discharging from the process equipment together with the fibres—in FIG. 2 being the water flow leaving the press 24 with the pulp. F R is the volume flow discharging from the process equipment together with the reject—in FIG. 2 being the water flow leaving the press 28 with the reject. F B is the volume flow discharging from the process equipment to enter the biological treatment plant, including, in FIG. 2, the filtrates of the pulp washer 23 and the press 24 as well as the filtrates of the reject presses 28 and 29 .
[0075] Not only does the invention help to minimize the retention time t of the process, but it also prevents the minimizing of the process flow F B passed to biological treatment, something that has been common practice in the traditional process. In the traditional process the volume flows F K +F R discharging together with the fibres and the reject are altogether about 1-2 m 3 /t and F B is typically 3-5 m 3 /t. In the method according to the invention the flow FB is increased to a level of 5-50 m 3 /t, advantageously 10-30 m 3 /t. The flow increase from level 4 m 3 /t to level 10 m 3 /t affects the growth of microbes in the same way as halving the liquid volume of the process according to the equation t=V P /(F K +F R +F B ).
[0076] Thanks to the biological treatment of the circulation water the pH of the process is higher than in a corresponding process using fresh water. The circulation of waters through the biological treatment removes nutrients from the process waters, whereby the reaction rate constant r in the equation (2) decreases and the growth of microbes slows down.
[0077] When the fibre pulp is, in addition, treated thermally at a raised temperature, the finished fibre pulp does not contain living biological material.
[0078] The basic idea of the invention for diminishing microbial activity by decreasing the retention time of the process can well be applied also in traditional pulp and paper manufacture using waste paper. In such a case the amount of reject and the volume flow F R discharging with it are naturally smaller than when using municipal waste.
[0079] Instead of biological treatment another known water treatment method for reducing the amount of microbes in the water circulation may be used. Alternatively, the amount of water to be passed to the water treatment can be substituted with fresh water, when plenty of it is available.
[0080] The claims will now be presented, and, within the inventive idea defined by the claims, the details of the invention may vary and differ from what is presented above as exemplary only.
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Method and apparatus for producing fibre pulp and fuel out of municipal waste or for producing fibre pulp out of waste paper. To control the microbe content, the retention time of the process is kept shorter than 12 hours, advantageously shorter than 6 hours. This is achieved by minimizing the total liquid volume of the process and by increasing the amount of water being passed to water treatment from the process, which water, having been purified, is possibly returned to the process. The method may also include a phase in which the pulp is treated thermally in order to destroy the microbes present in it.
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FIELD OF THE INVENTION
[0001] The present invention relates to bioresorbable polymers derived from structural units comprising caprolactone, polyols and diisocyanates, and the manufacture of the bioresorbable polymers.
BACKGROUND OF THE INVENTION
[0002] Bioresorbable and/or biodegradable polymers (i.e. biopolymers) can be divided into natural and synthetic polymers. To the natural polymers belong e.g. proteins, polysaccharides and lignin. Synthetic biopolymers are e.g. aliphatic polyesters, polyorthoesters, some aliphatic polycarbonates, polyanhydrides and some polyurethanes. Biopolymers can also be produced by microbes e.g. polyhydroxy alkanoates. The most important group of biodegradable polymers is based on aliphatic polyesters, the degradation of which is mainly based on hydrolysable ester bonds. Bioresorbable polymers degrade in the physiological environment and the degradation products are eliminated through the kidneys or completely bioabsorbed. According to strict definition, biodegradable polymers require enzymes or micro-organisms for hydrolytic or oxidative degradation. But in general, a polymer that loses its mass over time in the living body is called an absorbable, resorbable, bioresorbable or biodegradable polymer. This terminology is applied in the present invention regardless of polymer degradation mode, in other words for both enzymatic and non-enzymatic degradation and/or erosion.
[0003] Biodegradable polymers are used and studied in an increasingly large number of biomedical applications, such as controlled drug delivery devices, implants and resorbable sutures, as well as mass produced applications such as packaging, paper coating, fibres, films and other disposable articles. These applications bring special requirements to the polymers and monomers. These polymers are generally required to be biodegradable and non-toxic, or in the biomedical applications, bioresorbable and/or biocompatible. On the other hand, polymers should have good chemical, mechanical, thermal and rheological properties.
[0004] In the last few decades, novel controlled drug delivery systems have attracted interest due to their potential advantages. For example, the safety and efficacy of many drugs can be improved if they are administered by novel delivery systems. For many drugs a constant plasma concentration is desirable, especially for those drugs exhibiting narrow therapeutic indexes. Bioabsorbable devices represent the state of the art in drug delivery and in managing orthopaedic problems such as the use of implants in fracture fixation and ligament repair. Biodegradable polymers applied as drug delivery systems generally require no follow-up surgical removal once the drug supply has been depleted. Mainly implantable rods, microspheres and pellets have been investigated.
[0005] Polycaprolactone (PCL) is among the most common and well-studied bioresorbable polymer. The repeating molecular structure of PCL homopolymer consists of five non-polar methylene groups and a single relatively polar ester group. This high molecular weight polyester is conventionally produced by the ring-opening polymerisation of the cyclic monomer, i.e. ε-caprolactone. A catalyst is used to start the polymerisation and an initiator, such as an alcohol, can be used to control the reaction rate and to adjust the average molecular weight. PCL is a semi-crystalline (˜40-50%), strong, ductile and hydrophobic polymer with excellent mechanical characteristics having a low melting point of 60° C. and a glass transition temperature of −60° C.
[0006] Poly(ethylene glycol) is a biocompatible and highly water soluble (hydrophilic) polymer. Poly(ethylene glycols) are low molecular weight (<20000 g/mol) poly(ethylene oxides) containing the repeat unit —CH 2 CH 2 O—. PEG is a highly crystalline (˜90-95%) polymer having a low melting point of 60° C. and a glass transition temperature of −55 to −70° C. These difunctional compounds contain hydroxyl end-groups, which can be further reacted and chain extended with diisocyanates or used as initiators for ring-opening polymerisations. PEGs are well-known structural units incorporated into crosslinked polyurethane hydrogels (EP publications EP0016652 and EP0016654) and linear polyurethane hydrogels (PCT publication WO2004029125).
[0007] Amphiphilic block copolymers, e.g. PEG-PCL copolymers, have recently attracted attention in the field of medicine and biology as micellar carriers, polymer vesicles and polymer matrices. The triblock copolymer PCL-PEG-PCL has unique phase behaviour in blends and the ability to form polymeric micelle-like core-shell nanostructures in a selective solvent, in which only one block is soluble ( J. Polym. Sci. Part A Polym. Chem., 1997, 35, 709-714 ; Adv. Drug Delivery Rev., 2001, 53, 95-108).
[0008] However, the above-mentioned polymers suffer from a number of practical disadvantages. The degradation rate and mechanism appear to depend on a number of factors, such as the chemical structure of the polymer and on the surrounding environmental conditions, such as the degradation media. Two stages have been identified in the degradation process of aliphatic polyesters. Initially, the degradation proceeds by random hydrolytic chain scission of the ester bonds, leading to a decrease in the molecular weight; in the second stage measurable weight loss in addition to chain scission is observed. Another observation is that polycaprolactone degrades much slower than e.g. polylactide. The long degradation time of polycaprolactone (˜24 months) is usually a disadvantage for medical applications.
[0009] It is an object of the present invention to obviate and/or mitigate the disadvantages of the known bioresorbable polymers. In particular, it is an object of the present invention to provide a consistent and/or flexible approach to providing polymers having differing degradation properties which may be chosen according to the intended use of the polymers, including providing polymers having differing degradation rates. It is a further object to provide bioresorbable polyurethane polymers which fulfil one or more of these objects. A preferable object is to provide bioresorbable polyurethane polymers which are non-toxic on degradation.
SUMMARY OF THE INVENTION
[0010] According to a first aspect of the present invention, there is provided a polymer obtainable by reacting together:
[0000] (a) a prepolymer comprising co-polymerised units of a caprolactone and poly(alkylene oxide) moieties;
(b) a polycaprolactone diol comprising co-polymerised units of a caprolactone and a C 2 -C 6 diol; and
(c) a diisocyanate.
[0011] Alternatively stated, the invention provides a polymer comprising moieties derived from the stated components (a), (b) and (c) bonded together.
[0012] Preferably, the poly(alkylene oxide) moieties of the prepolymer (component (a)), are selected from a poly(C 2 -C 3 alkylene oxide) or mixtures thereof. Most preferred is a poly(C 2 alkylene oxide), e.g. derived from a poly(C 2 alkylene oxide) diol, i.e. poly(ethylene oxide) diols, for example poly(ethylene glycols). Generally and desirably, the poly(alkylene oxide) moieties should be water soluble to assist in the degradation of the subject polymers in aqueous environments.
[0013] Poly(ethylene glycols), which are an example of a polyethylene oxide, may be prepared by the addition of ethylene oxide to ethylene glycol to produce a difunctional polyethylene glycol having the structure HO(CH 2 CH 2 O) n H wherein n is an integer from 1 to 800 depending on the molecular weight. Polyethylene oxides contain the repeat unit (CH 2 CH 2 O) and are conveniently prepared by the stepwise addition of ethylene oxide to a compound containing a reactive hydrogen atom.
[0014] The poly(ethylene glycols) used in the present invention are generally linear polyols having an average molecular weight of about 200 g/mol to about 35,000 g/mol, particularly about 300 g/mol to about 10,000 g/mol, especially about 400 g/mol to about 8000 g/mol, for example about 400, 600, 2000, 4000 or 8000 g/mol.
[0015] Preferably, therefore, component (a) comprises a co-polymer of caprolactone and a relatively low to middle range molecular weight poly(ethylene glycol).
[0016] Component (a) may be made, for example by polymerising together the caprolactone and the polyol comprising poly(alkylene oxide) moieties, to provide a linear dihydroxyl-terminated caprolactone-poly(alkylene oxide) co-polymer for use as a prepolymer in the preparation of the subject polymer.
[0017] For example, ε-caprolactone may be reacted, in a ring opening reaction, with a poly(ethylene glycol) to provide a linear dihydroxyl-terminated caprolactone-poly(ethylene glycol) co-polymer for use as a prepolymer in the preparation of the subject polymer.
[0018] Such prepolymer typically has an ABA structure e.g. (CAP) n -PEG-(CAP) n , i.e. one having blocks of continuous caprolactone units flanking a PEG unit, e.g. -CAP-CAP-CAP-PEG-CAP-CAP-CAP-, and the average number of continuous units (i.e. the value of n) of caprolactone in each block of the polycaprolactone segments is generally between about 3 to 40, preferably between about 4 to 35, and typically between about 5 to 31, for example, chosen from 5, 9.5 and 31 units.
[0019] Typically, in the preparation of component (a), the polymerisation proceeds with the aid of a catalyst. A typical catalyst useful in the polymerisation is stannous octoate.
[0020] The skilled person will appreciate that in the preparation of the prepolymer (component (a)), the poly(alkylene oxide) moiety, which as mentioned herein above is preferably a poly(ethylene glycol) (i.e. PEG), may be considered as an initiator. The precise reaction conditions used will be readily determined by those skilled in the art. Other co-monomers, co-polymers, and catalysts in this ring-opening polymerisation may be used, if different properties are desired in the product, such as elasticity, degradation and release rate, and the choice of such other ingredients will be apparent to those of skill in the art.
[0021] Generally, in the preparation of the prepolymer, the molar ratio of caprolactone to initiator (e.g. the PEG) is generally in the range from about 2: about 1 up to about 124: about 1, for example about 10: about 1, about 19: about 1 or about 62: about 1.
[0022] The C 2 -C 6 diol component of the polycaprolactone diol (component (b)), may be any organic diol having a relatively lower molecular weight compared to the poly(alkylene oxide) moiety contained in the prepolymer diol component (a).
[0023] For example, the C 2 -C 6 diol, may be chosen from diols having a structure: HO—(CH 2 ) m —OH, wherein m is a number chosen from 2-6, for example, 1,2-ethylene glycol, 1,4-butane diol, 1,5-pentane diol or 1,6-hexane diol.
[0024] Alternatively, the C 2 -C 6 diol may be chosen from diols which are low molecular weight polymers or oligomers chosen from poly(alkylene oxide) diols.
[0025] Preferably, such poly(alkylene oxide) diol is selected from a poly(C 2 -C 3 alkylene oxide) diol or mixtures thereof. Most preferred are low molecular weight poly(C 2 alkylene oxide) diols, i.e. low molecular weight poly(ethylene oxide) diols, for example low molecular weight poly(ethylene glycols).
[0026] Typically, the low molecular weight poly(ethylene glycol) has the following structure: HO—(CH 2 CH 2 O) n —H, wherein n is a number chosen from 2 or 3, i.e. low molecular weight polyethylene glycols are preferred. An alternatively preferred diol is ethylene glycol itself (i.e. wherein n is 1).
[0027] The most preferred diol is diethylene glycol, i.e. an ethylene glycol dimer, which has the structure HO—CH 2 CH 2 —O—CH 2 CH 2 —OH.
[0028] Generally and desirably, the C 2 -C 6 diol should be water soluble to assist in the degradation of the subject polymers in aqueous environments.
[0029] The caprolactone moiety of the polycaprolactone diol (component (b)) is preferably derived from ε-caprolactone. Thus, the polycaprolactone diol is preferably derived from ε-caprolactone in a ring opening reaction using the low molecular weight diol as an initiator which itself becomes incorporated into the polycaprolactone diol. For example, such polycaprolactone diol, may be prepared by reacting ε-caprolactone and diethylene glycol in a ring opening reaction to provide a linear dihydroxyl-terminated poly(co-caprolactone-diethylene glycol). A catalyst may be used in the preparation of the polycaprolactone diol. Suitable catalysts include stannous octate, aluminium isopropoxide and/or titanium n-butoxide.
[0030] The ratio of caprolactone to low molecular weight diol initiator may be chosen according to principles readily available to the skilled person. Typically, when low molecular weight poly(ethylene glycol) is used as the low molecular weight diol, the ratio of caprolactone:ethylene glycol is of the order of about 4: about 2, and the co-polymer may have the following structure as an example: OH-CAP-CAP-EG-EG-CAP-CAP-OH, where CAP represents the opened caprolactone ring in the appropriate orientation, i.e. the unit —(CH 2 ) 5 C(O)O— or —O(O)C(CH 2 ) 5 — and EG represents an ethylene glycol unit. It will be appreciated that the order and positioning of the CAP units in the co-polymer molecules may vary.
[0031] The diisocyanate component (c) is preferably 1,4-butane diisocyanate, 1,6-hexamethylene diioscyanate, or L-lysine diisocyanate etc.
[0032] Such diisocyanates are particularly suitable for applications in which toxic degradation products are to be avoided, e.g. in biomedical applications.
[0033] 1,4-butane diisocyanate is preferred.
[0034] Known biomedical and biodegradable polyurethanes usually contain aromatic, cycloaliphatic or aliphatic diisocyanates, which may produce toxic substances or fragments upon degradation. It is generally accepted that, in the degradation of polyurethanes, any unreacted diisocyanate structural units hydrolyze to their corresponding amines. Most of these diamines are known to be toxic, carcinogenic and/or mutagenic. In the international publication WO9964491, the use of the non-toxic 1,4-butane diisocyanate (BDI) is shown in the manufacture of biomedical polyurethanes having a uniform block-length. The Applicant of the present invention considers that the use of 1,4-butane diisocyanate has a number of advantages because on degradation it yields 1,4-butane diamine, also known as putrescine, which is present in mammalian cells. ( J. Polym. Bull., 1997, 38, 211-218).
[0035] Thus, an additional advantage of at least one embodiment of the present invention is the use of biocompatible starting materials in the manufacture of the polyurethanes, which produce non-toxic, biocompatible polymers and degradation products.
[0036] However, in applications in which the toxicity of the degradation products is not as important, any diisocyanate commonly used to form polyurethanes may be used, (including those listed above) and including diisocyanates such as, dicyclohexylmethane-4,4-diisocyanate and diphenylmethane-4,4-diisocyanate.
[0037] The bioresorbable polymers of the present invention may degrade in the physiological environment of animals and the degradation products are eliminated through the kidneys or completely bioabsorbed. According to one definition, biodegradable polymers require enzymes or micro-organisms for hydrolytic or oxidative degradation. But in general, a polymer that loses its mass over time in the living body is called an absorbable, resorbable, bioresorbable or biodegradable polymer. This terminology is applied in the present invention regardless of polymer degradation mode, in other words for both enzymatic and non-enzymatic degradation and/or erosion.
[0038] As indicated above, the polymerisation process used to manufacture the bioresorbable polymer of the present invention typically involves a ring-opening polymerisation and a polyaddition reaction to obtain high molecular weight poly(block-caprolactone-co-PEG) urethanes. Accordingly, the present invention also extends to the process used to manufacture the polymers.
[0039] According to a further aspect of the present invention there is provided a method for preparing a polymer comprising:
[0000] (1) providing:
(a) a prepolymer comprising co-polymerised units of a caprolactone and poly(alkylene oxide) moieties; (b) a polycaprolactone diol comprising co-polymerised units of a caprolactone and a C 2 -C 6 diol; and (c) a diisocyanate; and
(2) reacting components (a), (b) and (c) together.
[0043] In the preparation of the subject polymer, the prepolymer component (a) can be reacted with components (b) and (c) to provide the final polymer. Preferably, the prepolymer is first combined, such as by admixing (for example by blending) with component (b), followed by reaction with component (c) diisocyanate.
[0044] The skilled person will appreciate that other modes of operation may be used to produce the polymers.
[0045] The component (a) prepolymer is generally produced by polymerising together caprolactone and a poly(alkylene oxide) diol. Preferably a catalyst is used during this to polymerisation reaction. The reaction is preferably conducted in an inert atmosphere, such as under an atmosphere of dry nitrogen gas.
[0046] Suitable catalysts include stannous octate, aluminium isopropoxide and/or titanium n-butoxide.
[0047] By using different molar ratios of component (a) (prepolymer), component (b) (e.g. poly(co-caprolactone-diethylene glycol) and diisocyanate (e.g. BDI), the phase structure, degradation rate and mechanical properties of the end polymer products may be tailored. The skilled person may judiciously choose the ratios of components and the reaction times, temperatures and other conditions appropriate to provide the final desired polymer product properties.
[0048] Generally, the mole ratio of component (a) to component (b) to component (c) is in the range of about 0.15-1.5 to about 1.0 to about 1.0-2.75, particularly about 0.2-1.0 to about 1.0 to about 1.25-2.5. A preferred range is about 0.25-1.0 to about 1.0 to about 2.5.
[0049] As described herein above, the present invention typically employs a two-step polymerisation method, which includes a ring-opening polymerisation and chain extending reaction, in the manufacture of the subject bioresorbable polymer. This straightforward two-step process offers a number of versatile possibilities for tailoring the structure and properties of the polymer components (a) and (b), and the final polymer, thus enabling the polymer to be used for a wide variety of purposes.
[0050] Numerous monomers and low molecular weight polymers may be introduced during the described steps of the synthesis, either during manufacture of components (a) or (b), or during preparation of the final polymer. Thus, a wide variety of polymer properties may be obtained in the final polymer using the above-mentioned materials by changing the molar composition. The present invention provides a solution to the typical drawbacks encountered with caprolactone/PEG-based copolymers, which include limited structure-property variations, slow degradation and dissolution rates.
[0051] Generally, any conventional polymerisation reactor may be used in the manufacture of the polyurethanes presented in the current invention, e.g. batch reactor, continuous stirred tank reactor (CSTR), extruder, reactive injection moulding (RIM), tube reactor, pipe reactor and/or melt mixer. Further processing of these biodegradable polymers can be done by using conventional processing methods suitable for thermoplastic polymers e.g. injection moulding, extrusion, pultrusion, blow moulding, vacuum moulding, solvent casting and other moulding and casting techniques, as well as dispersion, foam and film forming techniques.
[0052] As described above, the skilled reader will understand that the present invention is based on the discovery that only a few monomers and polymers appear to fulfil the required demands for tailored, non-toxic bioresorable polymers. Copolymerisation may be used to increase the degradation rate, and the degradation rate of caprolactone copolymers may be altered by varying the structure of the comonomers, the molar composition and the polymer molecular weight. The degradation media may also affect the degradation behaviour.
[0053] The polymers in the present invention may usefully be applied as drug delivery devices. The phase behaviour of the polymers consisting of a highly crystalline block and a rubbery block combined with the very hydrophilic and hydrophobic nature of each block makes them desirable as drug delivery systems because the permeability of each individual component or phase for different loaded drugs can differ widely depending on the properties of the particular drug loaded in the polymer. Furthermore, the flexible processes of the invention allow the properties of the polymer to be selected to suit a desired drug, and tailor how the drug is loaded and then released from the polymer. This offers the opportunity to generate a desired release profile for a chosen drug.
[0054] The bioresorbable polymers of the present invention may be applied to a wide range of uses, and such uses are included within the scope of the present invention. The polymer may be used as a matrix for drug delivery systems e.g. as drug loaded implants, micro and nanoparticles, micelles, patches, suppositories or contact lenses. Potentially any drug could be loaded into the bioresorbable polymers of the present invention. In addition, the bioresorbable polymer may be used in other biomedical applications such as implants, scaffoldings, nets or resorbable sutures, as well as mass-produced applications such as packaging, paper coating, fibres, films, foams or other disposable articles.
[0055] The present invention, therefore, also provides controlled release compositions comprising the bioresorbable polymer together with an active agent. The active agent may be a pharmaceutically active agent for human or animal use. It may also be any agent where sustained release properties (i.e algicides, fertilisers etc.) are required. Such compositions may be provided as pharmaceutical solid dosage forms, including suppositories, pessaries for vaginal use, buccal inserts for oral administration, transdermal patches or films, subcutaneous implants, etc.
[0056] The polymers of the present invention may be loaded with an active agent using any of the techniques readily available to the skilled person. One loading method may involve dissolving the polymer in a solution of the active agent and precipitating microparticles using double emulsion techniques. Other conventional processing techniques for processing thermoplastic polymers may also be applied for loading the polymers of the present invention with an active agent. For example, such techniques may include diffusion loading and tablet pressing techniques. Diffusion loading may involve for example uptake of an active agent from a solution contacting the polymer.
[0057] Pharmaceutically active agents of particular interest include:
[0058] Proteins such as interferon alpha, beta and gamma, insulin, human growth hormone, leuprolide; peptides such as oxytocin antagonists; enzymes and enzyme inhibitors; Benzodiazepines (e.g. midazolam); Anti-migraine agents (e.g. triptophans, ergotamine and its derivatives); Anti-infective agents (e.g. azoles, and treatments for bacterial vaginosis or candida); and opthalmic agents (e.g. latanoprost).
[0059] A detailed list of active agent includes H 2 receptor antagonist, antimuscarinics, prostaglandin analogue, proton pump inhibitor, aminosalycilate, corticosteroid, chelating agent, cardiac glycoside, phosphodiesterase inhibitor, thiazide, diuretic, carbonic anhydrase inhibitor, antihypertensive, anti-cancer, anti-depressant, calcium channel blocker, analgesic, opioid antagonist, antiplatelet, anticoagulant, fibrinolytic, statin, adrenoceptor agonist, beta blocker, antihistamine, respiratory stimulant, micolytic, expectorant, benzodiazepine, barbiturate, anxiolytic, antipsychotic, tricyclic antidepressant, 5HT 1 antagonist, opiate, 5HT 1 agonist, antiemetic, antiepileptic, dopaminergic, antibiotic, antifungal, anthelmintic, antiviral, antiprotozoal, antidiabetic, insulin, thyrotoxin, female sex hormone, male sex hormone, antioestrogen, hypothalamic, pituitary hormone, posterior pituitary hormone antagonist, antidiuretic hormone antagonist, bisphosphonate, dopamine receptor stimulant, androgen, non-steroidal anti-inflammatory, immuno suppressant local anaesthetic, sedative, antipsioriatic, silver salt, topical antibacterial, vaccine.
[0060] The polymers of the present invention degrade in water, aqueous buffer solutions, physiological fluids, soil, compost, sea water and fresh water, and the like over extended time periods. The composition of the polymer and the temperature may cause different degradation rates, which may be readily determined by the skilled person.
[0061] Generally, in use, the polymer may be subjected to a temperature of from about 10° C. to about 95° C., preferably from about 25° C. to 45° C., typically from about 30° C. to 38° C., e.g. 37° C.
[0062] The time taken for the polymer to fully degrade, i.e. lose all of its mass, may vary widely, e.g. typically of the order of from about one week to 150 weeks (i.e. about 3 years), preferably of from about 2 weeks to about 100 weeks, e.g. from about 2 weeks to about 60 weeks, such as 4 weeks or 52 weeks.
[0063] The degradation time can be tailored for the intended final application.
[0064] The Applicant has demonstrated that the objectives described herein are fulfilled by the subject polymers, in particular the caprolactone-PEG polyurethane co-polymers.
DETAILED DESCRIPTION OF THE INVENTION
[0065] Embodiments of the present invention are described in more detail in the following non-limiting examples, with reference to the drawings, in which,
[0066] FIG. 1 shows the biodegradation of Polymer 21 and Polymer 1 in demineralised water at 37° C.;
[0067] FIG. 2 shows the biodegradation of Polymer 11, Polymer 9, Polymer 15, Polymer 10, Polymer 8, Polymer 21 and Polymer 26 in phosphate buffer at 37° C.; and
[0068] FIG. 3 shows the biodegradation of Polymer 11 and Polymer 15 in demineralised water at 55° C.
EXAMPLE 1
Manufacture of Linear Bioresorbable Prepolymers with Different Structure and Block Lengths for Subsequent Polyurethane Synthesis
[0069] The length of PEG block (400, 600, 2000, 4000 and 8000 g/mol) and caprolactone block (500-3500 g/mol) was changed. The target prepolymer molecular weight was selected to be between 1000-11 000 g/mol. Prepolymer batch sizes were about 500-600 g. The prepolymers were prepared by varying their compositions as follows (see Table 1): Batch A) Prepolymer A made of 273.00 g PEG400 (15.7 mole-%), 418.17 g caprolactone (84.3 mole-%) and 0.528 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 1013 g/mol, Batch B) Prepolymer B made of 90.05 g PEG400 (5.0 mole-%), 488.10 g caprolactone (94.97 mole-%) and 0.547 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 2568 g/mol, Batch C) Prepolymer C made of 29.95 g PEG400 (1.6 mole-%), 525.48 g caprolactone (98.37 mole-%) and 0.569 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 7418 g/mol, Batch D) Prepolymer D made of 122.25 g PEG600 (5.0 mole-%), 441.76 g caprolactone (94.97 mole-%) and 0.495 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 2768 g/mol, Batch E) Prepolymer E made of 46.80 g PEG600, 547.41 g caprolactone and 0.592 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 7618 g/mol, Batch F) Prepolymer F made of 330.31 g PEG2000 (5.0 mole-%), 358.09 g caprolactone (94.97 mole-%) and 0.401 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 4168 g/mol, Batch G) Prepolymer G made of 152.76 g PEG2000 (1.6 mole-%), 536.06 g caprolactone (98.37 mole-%) and 0.580 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 9018 g/mol, Batch H) Prepolymer H made of 549.63 g PEG4000 (10.0 mole-%), 139.38 g caprolactone (89.97 mole-%) and 0.165 g tin(II)octoate (0.03 mole-%), targeting a theoretical molecular weight of 5077 g/mol, Batch I) Prepolymer I made of 447.28 g PEG4000 (5.0 mole-%), 239.45 g caprolactone (94.97 mole-%) and 0.268 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 6218 g/mol, Batch J) Prepolymer J made of 257.29 g PEG4000 (1.6 mole-%), 451.42 g caprolactone (98.37 mole-%) and 0.489 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 11018 g/mol, Batch K) Prepolymer K made of 584.57 g PEG8000 (10.0 mole-%), 75.04 g caprolactone (89.97 mole-%) and 0.089 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 9027 g/mol and Batch L) Prepolymer L made of 170.77 g PEG8000 (5.0 mole-%), 46.28 g caprolactone (94.97 mole-%) and 0.052 g tin(II) octoate (0.03 mole-%), targeting a theoretical molecular weight of 10168 g/mol.
[0000]
TABLE 1
Synthesised prepolymers for the present invention.
Reaction
Prepolymer
Theoretical MW
Theoretical MW
Number of CL units
Temperature
Name
PEG
of prepolymer
of PCAP block
in PCAP block
(° C.), time
Prepolymer A
400
1013
600
5
160, 5 h
Prepolymer B
400
2568
1084
9.5
160, 6 h
Prepolymer C
400
7418
3509
31
160, 5 h
Prepolymer D
600
2768
1084
9.5
160, 6 h
Prepolymer E
600
7618
3524
31
160, 5 h
Prepolymer F
2000
4168
1100
9.5
160, 5 h
Prepolymer G
2000
9018
3500
31
160, 5 h
Prepolymer H
4000
5077
538
5
160, 4 h
Prepolymer I
4000
6218
1109
9.5
160, 6 h
Prepolymer J
4000
11018
3500
31
160, 5 h
Prepolymer K
8000
9027
515
5
160, 5 h
Prepolymer L
8000
10168
1084
9.5
160, 5 h
[0070] The molecular weights (M n and M w ) and molecular weight distributions were measured for various prepolymers by a triple angle light scattering combined with size exclusion chromatography (SEC) system. Differential scanning calorimetry (DSC) was used to measure the glass transition temperature, melting point and crystallinity of the prepolymers, see Table 2.
[0000]
TABLE 2
Prepolymers were characterised using SEC coupled with light scattering and
DSC experiments.
Prepolymer
Mn (g/mol)
MWD
Tg 2
Tg 3
Tm 1
Tm 2
Tm 3
Name
SEC
SEC
Tg 1 (° C.)
(° C.)
(° C.)
(° C.)
(° C.)
(° C.)
Prepolymer A
—
—
−69.2
−43.2
—
−17.0
12.4
27.2
Prepolymer B
2249
1.37
−69.3
−21.6
11.0
41.6
48.3
—
Prepolymer C
7810
1.20
−67.1
−19.5
—
42.9
50.9
55.0
Prepolymer D
2583
1.29
−67.0
−10.1
—
39.8
46.7
53.1
Prepolymer E
8623
1.35
−66.9
−10.4
—
46.9
53.0
—
Prepolymer F
4525
1.27
—
—
—
26.8
—
—
Prepolymer G
8327
1.07
−65.3
−3.7
—
−47.1
50.9
—
Prepolymer H
5584
1.02
−67.1
−1.2
—
50.5
—
—
Prepolymer J
—
—
−66.3
—
—
34.7
54.6
—
Prepolymer K
—
—
—
—
—
54.7
—
—
Prepolymer L
—
—
—
—
—
52.3
—
—
EXAMPLE 2
Manufacture of a Linear Bioresorbable Hydrogel Prepolymer and Polymer (Prepolymer M and Polymer 1)
[0071] Into a 700 ml stirred tank reactor 319.00 g (10 mole-%) of dried PEG4000 (MW 4050 g/mol), 80.90 g (89.97 mole-%) ε-caprolactone and 0.096 g (0.03 mole-%) tin(II) octoate were fed in that order. Dry nitrogen was continuously purged into the reactor. The reactor was pre-heated to 160° C. using an oil bath and a mixing speed of 100 rpm. PEG4000 was dried and melted in a rota-evaporator prior to being added into the reactor. Then, ε-caprolactone was added and finally the catalyst tin(II) octoate. Prepolymerisation time for the PEG-PCL prepolymer was 4 hours. The theoretical molecular weight of the prepolymer was 5077 g/mol.
[0072] For the polymer preparation 400.08 g of low molecular weight poly(ε-caprolactone) diol (MW 530 g/mol) (PCLDI) were fed to the reactor and blended with the above mentioned prepolymer. The mole ratio used for the PEG-PCL prepolymer and polycaprolactone diol was 0.7:1. The blending was done under nitrogen for 30 min using a mixing speed of 100 rpm and a blending temperature of 160° C. The prepolymer and PCLDI mixture was stored in a refrigerator until required.
[0073] 47.245 g of PEG-PCL prepolymer and PCLDI mixture were fed into a 100 ml reactor and melted at 110° C. for 30 min under nitrogen. Mixing was set at 60 rpm and 3.139 ml of 1,4-butane diisocyanate (BDI), at a molar ratio of 0.7:1.0:1.7 PEG-PCL prepolymer: PCLDI: BDI, were fed into the reactor. Polymerisation time was 17 minutes. Polymer was scraped into an aluminium pan and stored in a desiccator for further testing. (Polymer 1)
EXAMPLE 3
Manufacture of a Linear Bioresorbable Polymer with a Different Structure
[0074] Prepolymer H (Table 1 in Example 1), and polycaprolactone diol (MW˜530 g/mol) were mixed, dried and melted under vacuum at 70° C. for at least one hour prior to feeding them into the preheated (110° C.) reactor. Reaction mixture was mixed (60 rpm) for 30 min under nitrogen before 1,4-butane diisocyanate was fed into the reactor. The molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 0.25:1.0:1.25. The reaction time was 150 minutes. (Polymer 2 and Polymer 3)
[0075] DSC analysis revealed that the glass transition temperature (T g ) and the melting point (T m ) were −48.7 and 38.9° C. respectively. The characteristic peaks of the urethane (N—H, 3341 cm −1 ) and ester bonds (C═O, 1731 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 4
Manufacture of a Linear Bioresorbable Polymer with a Different Structure
[0076] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer H in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2. The reaction time was 120 minutes. (Polymer 4).
[0077] DSC analysis revealed that the glass transition temperature (T g ) and the melting point (T m ) were −51.8 and 44.2° C. respectively. The characteristic peaks of the urethane (N—H, 3354 cm −1 ) and ester bonds (C═O, 1728 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 5
Manufacture of a Linear Bioresorbable Polymer with a Different Structure
[0078] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer J in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2. The reaction time was 20 minutes. (Polymer 5).
[0079] DSC analysis revealed that the glass transition temperature (T g ) and the melting points (T m ) were −58.9, 17.1 and 44.7° C. respectively. The characteristic peaks of the urethane (N—H, 3384 cm −1 ) and ester bonds (C═O, 1721 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 6
Manufacture of a Linear Bioresorbable Polymer with a Different Structure
[0080] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer J in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2.5. The reaction time was 120 minutes. (Polymer 6).
[0081] DSC analysis revealed that the glass transition temperature (T g ) and the melting points (T m ) were −58.7, 16.3 and 43.6° C. respectively. The characteristic peaks of the urethane (N—H, 3381 cm −1 ) and ester bonds (C═O, 1739 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 7
Manufacture of a Linear Bioresorbable Polymer with a Different Structure
[0082] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer B in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2.1. The reaction time was 2 minutes. (Polymer 7).
[0083] DSC analysis revealed that the glass transition temperature (T g ) and the melting point (T m ) were −54.1 and 36.1° C. respectively. The characteristic peaks of the urethane (N—H, 3379 cm −1 ) and ester bonds (C═O, 1721 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 8
Manufacture of a linear bioresorbable polymer with a different structure
[0084] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer C in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2.1. The reaction time was 60 minutes. (Polymer 8).
[0085] DSC analysis revealed that the glass transition temperature (T g ) and the melting point (T m ) were −61.4 and 49.5° C. respectively. The characteristic peaks of the urethane (N—H, 3387 cm −1 ) and ester bonds (C═O, 1728 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 9
Manufacture a Linear Bioresorbable Polymer with a Different Structure
[0086] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer D in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2. The reaction time was 60 minutes. (Polymer 9).
[0087] DSC analysis revealed that the glass transition temperature (T g ) and the melting point (T m ) were −55.7 and 31.7° C. respectively. The characteristic peaks of the urethane (N—H, 3378 cm −1 ) and ester bonds (C═O, 1728 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 10
Manufacture of a Linear Bioresorbable Polymer with a Different Structure
[0088] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer D in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2.2. The reaction time was 90 minutes. (Polymer 10).
[0089] DSC analysis revealed that the glass transition temperature (T g ) and the melting point (T m ) were −56.1 and 32.7° C. respectively. The characteristic peaks of the urethane (N—H, 3338 cm −1 ) and ester bonds (C═O, 1721 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 11
Manufacture of a Linear Bioresorbable Polymer with a Different Structure
[0090] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer E in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2. The reaction time was 60 minutes. (Polymer 11).
[0091] DSC analysis revealed that the glass transition temperature (T g ) and the melting point (T m ) were −61.1 and 49.1° C. respectively. The characteristic peaks of the urethane (N—H, 3386 cm −1 ) and ester bonds (C═O, 1728 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 12
Manufacture of a Linear Bioresorbable Polymer with a Different Structure
[0092] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer F in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2.2. The reaction time was 120 minutes. (Polymer 12).
[0093] DSC analysis revealed that the glass transition temperature (T g ) and the melting point (T m ) were −55.4 and 22.2° C. respectively. The characteristic peaks of the urethane (N—H, 3381 cm −1 ) and ester bonds (C═O, 1732 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 13
Manufacture of a Linear Bioresorbable Polymer with a Different Structure
[0094] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer G in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2. The reaction time was 120 minutes. (Polymer 13).
[0095] DSC analysis revealed that the glass transition temperature (T g ) and the melting point (T m ) were −63.4 and 44.1° C. respectively. The characteristic peaks of the urethane (N—H, 3384 cm −1 ) and ester bonds (C═O, 1721 cm −1 ) were identified in the bioresorbable polymer using FTIR.
EXAMPLE 14
Manufacture of a Linear Bioresorbable Polymer with a Different Structure
[0096] The chain extending polymerisation was performed as in Example 3, except the prepolymer was Prepolymer K in Table 1 in Example 1 and the molar ratio between prepolymer, poly(ε-caprolactone) diol and BDI was 1:1:2. The reaction time was 120 minutes. (Polymer 14).
[0097] DSC analysis revealed that the glass transition temperature (T g ) and the melting point (T m ) were −51.5 and 52.1° C. respectively. The characteristic peaks of the urethane (N—H, 3357 cm −1 ) and ester bonds (C═O, 1732 cm −1 ) were identified in the bioresorbable polymer using FTIR.
[0000]
TABLE 3
Synthesised bioresorbable polymers for the present invention.
Theoretical
Theoretical
Reaction
Polymer
Prepolymer
MW of
MW of
Prepolymer
CAP-diol
BDI
Temperature
Name
PEG
Name
prepolymer
CAP block
Mol ratio
(° C.), time
Polymer 8
400
Prepolymer C
7418
3509
1
1
2.1
120, 1 h
Polymer 7
400
Prepolymer B
2568
1084
1
1
2.1
120, 2 min
Polymer 11
600
Prepolymer E
7618
3524
1
1
2
120, 1 h
Polymer 9
600
Prepolymer D
2768
1084
1
1
2
120, 1 h
Polymer 15
600
Prepolymer D
2768
1084
1
1
2.1
120, 1 h
Polymer 10
600
Prepolymer D
2768
1084
1
1
2.2
120, 1 h
30 min
Polymer 16
2000
Prepolymer F
4168
1100
1
1
2
110, 2 h
Polymer 17
2000
Prepolymer F
4168
1100
1
1
2.1
110, 2 h
Polymer 12
2000
Prepolymer F
4168
1100
1
1
2.2
110, 2 h
Polymer 13
2000
Prepolymer G
9018
3500
1
1
2
110, 2 h
Polymer 18
2000
Prepolymer G
9018
3500
1
1
2.1
110, 2 h
Polymer 19
2000
Prepolymer G
9018
3500
1
1
2.2
110, 2 h
Polymer 20
2000
Prepolymer G
9018
3500
1
1
2.2
140, 2 h
Polymer 1
4000
Prepolymer M
5077
538
0.7
1
1.7
Polymer 21
4000
Prepolymer M
5077
538
0.7
1
1.53
Polymer 22
4000
Prepolymer M
5077
538
0.7
1
1.36
Polymer 23
4000
One-pot
5077
538
0.7
1
1.53
160, 6 min
Polymer 2
4000
Prepolymer H
5077
538
0.25
1
1.25
110, 2 h
30 min
Polymer 24
4000
Prepolymer H
5077
538
0.25
1
1.4
110, 2 h
Polymer 3
4000
Prepolymer H
5077
538
0.25
1
1.25
110, 2 h
25 min
Polymer 4
4000
Prepolymer H
5077
538
1
1
2
110, 2 h
Polymer 25
4000
Prepolymer I
6218
1109
0.25
1
1.25
110, 4 h
Polymer 26
4000
Prepolymer I
6218
1109
0.25
1
1.25
110, 2 h
Polymer 27
4000
Prepolymer I
6218
1109
0.25
1
1.25
110, 2 h
Polymer 5
4000
Prepolymer J
11018
3500
1
1
2
110, 20 min
Polymer 28
4000
Prepolymer J
11018
3500
1
1
2.1
110, 30 min
Polymer 30
4000
Prepolymer J
11018
3500
1
1
2.2
110, 20 min
Polymer 31
4000
Prepolymer J
11018
3500
1
1
2.2
140, 1 h
Polymer 32
4000
Prepolymer J
11018
3500
1
1
2.3
110, 1 h
Polymer 33
4000
Prepolymer J
11018
3500
1
1
2.4
110, 2 h
Polymer 6
4000
Prepolymer J
11018
3500
1
1
2.5
110, 2 h
Polymer 14
8000
Prepolymer K
9027
515
1
1
2
110, 2 h
Polymer 34
8000
Prepolymer K
9027
515
1
1
2.1
110, 2 h
Polymer 35
8000
Prepolymer K
9027
515
1
1
2.2
110, 2 h
EXAMPLE 15
[0098] Molecular weight determination was carried out for a selected number of bioresorbable polymers, which are shown in Table 4. The molecular weight of the polymer will determine its mechanical properties and have an impact on its degradation properties; therefore the importance of determining molecular weight values is evident.
[0099] These types of polymers are expected to have a molecular weight of 100,000 (M n ) in the best of cases. The minimum value for the M n to have reasonable mechanical properties or to consider the compound a polymer is 30,000. In the present invention molecular weight values for M n exceeded our expectations and values of well over 100,000 were obtained in most cases.
[0000]
TABLE 4
Molecular weight analyses for selected bioresorbable polymers.
Example
Polymer
Prepolymer
Mw (g/mol)
Mn (g/mol)
MWD
Number
Name
PEG
Name
SEC
SEC
SEC
Polymer 16
2000
Prepolymer F
71,030
25,380
2.80
12
Polymer 12
2000
Prepolymer F
343,600
251,600
1.37
Polymer 18
2000
Prepolymer G
238,300
141,900
1.68
Polymer 19
2000
Prepolymer G
218,400
126,600
1.72
Polymer 20
2000
Prepolymer G
209,700
129,000
1.62
4
Polymer 4
4000
Prepolymer H
206,700
131,700
1.57
5
Polymer 5
4000
Prepolymer J
145,100
84,750
1.71
Polymer 28
4000
Prepolymer J
191,400
126,700
1.51
Polymer 30
4000
Prepolymer J
163,300
102,400
1.59
Polymer 31
4000
Prepolymer J
146,900
87,210
1.68
Polymer 32
4000
Prepolymer J
185,500
111,100
1.67
Polymer 33
4000
Prepolymer J
136,600
76,960
1.77
6
Polymer 6
4000
Prepolymer J
130,700
73,610
1.78
14
Polymer 14
8000
Prepolymer K
198,300
153,900
1.29
Polymer 34
8000
Prepolymer K
170,200
116,900
1.46
Polymer 35
8000
Prepolymer K
160,600
115,700
1.39
EXAMPLE 16
Purification of Bioresorbable Polymers by Solvent Precipitation
[0100] The polymers from Example 2 and 3 were purified after polymerisation by precipitation into a non-solvent. Initially the polymers were dissolved using dichloro methane (DCM), chloroform or tetrahydrofuran (THF) as solvents and diethyl ether as the precipitating solvent. Precipitated polymers were vacuum dried and kept in a desiccator until further testing was required.
EXAMPLE 17
Processing of Thermoplastic Polymers by Using a Hot-Press and Solvent Casting—Film Production
[0101] The bioresorbable polymers from Example 3 were dried under vacuum over night prior to processing them using the hot-press. Upper and lower plate temperatures were set at 130° C. Two Teflon sheets were placed between the mould and the hot plates. The melting time was 2 min followed by a 30 second holding under pressure (−170 bar). An exact amount of polymer was used to fill the mould. After cooling to room temperature samples (30 mm×10 mm×1 mm) were mechanically punched out and kept in the freezer for further analysis.
[0102] Solvent cast films: a number of polymers from Table 3 were dissolved in DCM and poured into aluminium pans followed by overnight solvent evaporation in the fume cupboard.
EXAMPLE 18
One Month Degradation Investigation at 37° C. in Water
[0103] In order to prove the bioresorbability of the synthesised polymers, a few polymers were selected to carry out biodegradation studies (Examples 18-20).
[0104] Polymer samples (size 30×10×1 mm) for degradation studies were made from the biodegradable polymers by hot-pressing films and punching specimens out of it. There were 2 different types of degradation studies: one at 37° C. in phosphate buffer saline solution pH 7.4 (for 6-16 months) Example 19 and another one in water (for 1 month) Example 18 and an accelerated study at 55° C. in demineralised water (for 3 months) Example 20. At the beginning samples were taken every week and after one month once a month or even less frequently. The degradation results at 37° C. in water and in phosphate buffer can be seen in FIGS. 1 and 2 , respectively. The accelerated degradation can be found in FIG. 3 .
[0105] Without wishing to be bound by theory, it is believed that the degradation mechanism of bulk degrading/eroding polymers, which is typical for most polyester based polymers, consists of two main stages. In the first stage, the molecular weight of the polymer starts to degrade and the water uptake or swelling % increases. At a later stage, when the molecular weight of the polymer decreases below 15000 g/mol the weight or mass loss starts to occur. Biomaterials, 1981, 2, 215-220. The limit for the weight loss to happen depends on the nature of the polymer and its solubility in the surrounding media. Hydrophilic and hydrophobic blocks may change the degradation mechanism. For example extremely hydrophobic polymers with hydrolytically labile bonds produce surface eroding polymers while hydrophilic structure units in the polyesters may remove the autocatalytic effect of acidic degradation products and produce “real” bulk degradation without the empty shell effect.
EXAMPLE 19
Fifteen Months Degradation Investigation at 37° C. in Buffered Saline Solution
[0106] The pessaries for the biodegradation study were prepared as in Example 18. The degradation could be readily tailored by changing the polymer. Polymers were tailor made to suit degradation.
EXAMPLE 20
Six Months Degradation Investigation at 55° C. in Demineralised Water
[0107] The pessaries for the biodegradation study were prepared as in Example 18. The higher temperature increased the degradation rate.
[0108] The Applicant of the present invention has therefore, in at least one embodiment, provided a bioresorbable polymer obtainable from caprolactone and PEG, which differs from previous polymers in composition, properties, manufacturing method, degradation rate and use.
[0109] The applicant of the present invention has found that the properties of previous bioresorbable polymers were dependent on either the caprolactone or PEG properties. By using diisocyanate, which extends the polymer chains and a caprolactone diol, the polymers of the present invention can incorporate aspects of all moieties. Surprisingly, the applicant has found that the combination of three polymerisation techniques gives a greater control over the polymer structure, resulting in extremely useful properties.
[0110] The above described specific embodiments are not to be considered to limit the invention described herein.
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A bioresorbable polymer is obtained by reacting together (a) a prepolymer comprising co-polymerised units of a caprolactone and poly(alkylene oxide) moieties; (b) a polycaprolactone diol comprising co-polymerised units of a caprolactone and a C 2 -C 6 diol; and (c) a diisocyanate. The polymer may be loaded with a pharmaceutically active agent to produce a drug delivery device.
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This application is a division of application Ser. No. 07/931,784 filed Aug. 18, 1992, now abandoned, which in turn is a division of application Ser. No. 07/742,066 filed Aug. 7, 1991, now U.S. Pat. No. 5,162,817, issued Nov. 10, 1992, which in turn is a continuation of application Ser. No. 07/470,745 filed Jan. 26, 1990, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet head, ink tank and ink jet apparatus capable of preventing an erroneous detection due to change of ink component and having an improved ink residual quantity detecting means.
2. Related Background Art
Conventional means for detecting residual ink quantity used in ink jet recording apparatus are generally divided into the following three groups:
(1) Detection means wherein the residual ink detection is performed by detecting the change in resistance and turned ON or OFF in accordance with the presence or absence of ink between two electrodes;
(2) Detection means wherein the residual ink detection is performed by detecting the analogous change in volume of ink between two electrodes; and
(3) Detection means wherein the residual ink detection is based on the resistance residing in an absorbent member between two electrodes.
However, in the conventional ink jet recording apparatuses, when a different color ink or different type ink (for being used with plain paper or coated paper) or OHP (transparency for OHP (overhead projection) (referred "TP" hereinafter) was used while including the same single residual ink detection means, there arose a problem that the erroneous detection was derived from the fact that the volume resistance of a respective ink is varied or changed in accordance with the change in ink components (caused when the kind of dyne and/or kind of solvents and/or ratio of composition are different).
Generally, the ink tank is constructed in the form of a cartridge which is exchanged when the ink is consumed, but when a variation among cartridges exists, there is a possibility that the detection accuracy might decrease in the construction in which residual quantity detection is effected by comparing the resistance value between the electrodes with a basic or reference value. Such disadvantage is caused by variation of the absorbing member in a cartridge having an absorbing member with ink impregnated thereinto for preventing the solution of gas and leakage of ink generated vibration of the ink by shock upon transportation or the like.
Recently, the skill for making the recording head and ink tank into cartridge-like construction (cartridge) has been developed, since the recording head can be manufactured cheaply or in low cost by using an electric-thermal converting member as an energy generating element for ink discharge. It is advantageous to impregnate the ink into the absorbing member because an ink head pressure (pressure generated at the discharge opening by water head difference) at the discharge opening of recording head can be stabilized. However, there is fear that detecting accuracy of the residual ink quantity might be decreased in the manner in which the residual ink quantity is judged by comparison of resistance value between the electrodes with a uniform reference value, because there is occurred air bubbles present upon the ink discharge in addition to the above variation of absorbing members.
SUMMARY OF THE INVENTION
An object of the present invention is to prevent occurrence of erroneous detection and to provide an ink jet recording head, ink tank and ink jet recording apparatus in which various qualities have been improved.
Another object of the present invention is to provide the ink tank and ink jet recording head capable of effecting the residual ink quantity detection of high accuracy and stability with relatively simple construction.
It is an object of the present invention to provide a device for detecting whether the amount of ink remaining in an ink supply source of an ink jet recording apparatus has reached a level unsuitable for recording, wherein the ink supply source includes electrodes for passing electric current through the ink in the ink supply source, the device comprising information determining means for determining reference information corresponding to a resistance by applying an electric current to the electrodes when the ink supply source has a known predetermined amount of ink therein and for determining test information corresponding to a resistance by applying an electric current to the electrodes when the ink supply source has an unknown amount of ink therein, and judging means for judging whether or not the amount of ink in the ink supply source has reached the level unsuitable for recording by determining a relation between the reference information and the test information.
It is another object of the present invention to provide an ink jet recording apparatus utilizing a detachably mountable ink jet cartridge including an ink jet recording head for ejecting ink onto a recording medium and an ink supply source containing ink for supply to said ink jet recording head, the ink supply source having electrodes for passing an electric current through the ink in said ink supply source, the apparatus comprising information determining means for determining reference information corresponding to a resistance by applying an electric current to the electrodes when the ink jet cartridge is mounted to the apparatus and for determining test information corresponding to a resistance by applying an electric current to the electrodes a predetermined time after the ink jet cartridge is mounted to the apparatus, and judging means for judging whether or not the amount of ink in the ink supply source has reached a level unsuitable for recording by determining a relation between the reference information and the test information.
It is yet another object of the present invention to provide a method of detecting when the ink level in an ink supply source for an ink jet recording apparatus has reached a level unsuitable for recording, the method comprising the steps of establishing a reference resistance by passing an electric current through the ink in the ink supply source when the ink supply source has a known predetermined amount of ink therein, determining a test resistance by passing an electric current through the ink in the ink supply source after a predetermined amount of recording by the ink jet recording apparatus, and comparing the test resistance with a standard resistance.
It is still another object of the present invention to provide a method of detecting when the ink level in an ink supply source for an ink jet recording apparatus has reached a level unsuitable for recording, the method comprising the steps of establishing reference information corresponding to a resistance by passing an electric current through the ink in the ink supply source when the ink supply source has a known predetermined amount of ink therein, calculating from the reference information threshold information representing a level of ink in the ink supply source unsuitable for recording, determining test information corresponding to a resistance by passing an electric current through the ink in the ink supply source after a predetermined amount of recording by the ink jet recording apparatus, and comparing the test information with the threshold information.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic cross section showing one example of an ink jet recording apparatus including an ink jet recording cartridge according to the present invention;
FIGS. 2 and 4 are graphs showing relation between the residual ink quantity and resistance between electrodes;
FIGS. 3 and 5 are drawings showing detecting circuits for residual ink quantity;
FIGS. 6 and 7 are schematic cross section and perspective views showing another embodiment of the ink jet recording cartridge according to the present invention;
FIG. 8 is a schematic perspective view showing another embodiment of the ink jet recording cartridge according to still another embodiment of the present invention;
FIG. 9 is a schematic cross section showing still another embodiment of the ink jet recording cartridge according to the present invention;
FIG. 10 is a graph showing relation between the residual ink quantity and resistance between electrodes;
FIG. 11 is a schematic perspective view showing still another embodiment of the ink jet recording cartridge according to the present invention;
FIG. 12 is a schematic drawing showing an example of ink jet recording apparatus including an ink tank according to the present invention;
FIG. 13 is a schematic cross section showing still another example of the ink jet recording apparatus including the ink jet recording cartridge;
FIG. 14 is a graph showing the relation between the residual ink quantity and resistance between electrodes;
FIG. 15 is a still another graph showing the relation between the residual ink quantity and resistance between electrodes resulting from variation the ink jet recording cartridge;
FIG. 16 is a drawing showing still another example of a detecting circuit of residual ink quantity;
FIG. 17 is a flow chart showing an operational sequence according to the present invention;
FIG. 18 is a drawing showing still another example of detecting circuit of a residual ink quantity;
FIG. 19 is a perspective view showing an ink jet recording apparatus according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention intends to correct the resistance value change of ink due to difference of color i.e. dye or the like by using correcting means provided on a residual quantity detecting apparatus with respect to resistance value from the electrode for residual quantity detection.
According to the present invention, even if an ink having different component is used in the same or common head, residual quantity detection can be effected accurately.
According to the present invention, the proper threshold can be determined corresponding to the ink supply source, so highly accurate detection of residual ink quantity can be effected without being effected by variations of the ink tank including the ink absorbing member.
Incidentally, residual quantity detection can be carried out at the head side or the tank side. In addition, in order to prevent an ink liquid surface from assuming a wave condition due to vibration or shock upon movement of the carriage, it is possible to insert the absorbing member into the head and ink tank. In the correcting circuit, an element having equivalent resistance change can be added for correction. Furthermore, temperature of the printing apparatus and ink can be monitored and corrected corresponding to resistance change of the ink due to temperature, which can lead to more accurate residual quantity detection.
Embodiment 1
FIG. 1 is a schematic view showing a disposable ink jet recording cartridge. On the cartridge, a recording head tip 1 and an ink tank 9 can be removably mounted. This cartridge is constructed so that the head pressure in the head tank 9 by single can be adjusted so as not to apply water head pressure onto the recording head tip 1 by inserting the absorbing member 6-2 into the ink tank 9. The recording head permits the recording or printing in the downward direction.
In FIG. 1, the reference numeral 1 denotes the above-mentioned recording head tip; and 2 denotes an ink discharging portion having the ability for discharging ink and including an ink discharge opening 2a and an ink path provided with energy generating means for generating thermal energy used for discharging the ink droplet and communicated with the discharge opening. The reference numeral 3 denotes a liquid chamber for temporarily reserving the ink to be sent the ink to the ink discharging portion; 4 denotes a flow passage for sending the ink to the liquid chamber; and 5 denotes a filter for removing bubbles and/or dust and the like. The reference numeral 6-1 denotes the above-mentioned absorbent member made of porous material or fiber material, and pin-shaped residual ink quantity detection electrodes 7a, 7b and 7c are arranged in the recording head wall to be inserted into the absorbent member 6-1. These elements constitute the recording head tip 1.
The reference numeral 9 denotes the above-mentioned ink tank, within which the above-mentioned absorbent member 6-2 and ink 10 are accommodated. 9a is a hole formed on the ink tank to be communicated with atmosphere. The ink tank 9 and the recording head tip 1 are removably combined with each other through insertion pins 8 and the like. In order to prevent leakage of the ink, O-ring 13 is provided. It is so designed that, when the ink tank 9 itself is stored, the ink therein does not lead from the ink tank, but, when it is combined with the recording head tip, the ink can flow from the ink tank to the recording head tip via an ink supplying part 13a.
Next, an electrical connection between the ink jet recording cartridge and a body of the recording apparatus itself will be explained. Although not shown in FIG. 1, as shown in FIG. 7, the recording head tip has a wiring member 11 (referred to as "lead frame" hereinafter) constituted by a plurality of plate-shaped conductors arranged side by side, and the reference numeral 12a, 12b and 12c (FIG. 3) denote electrodes incorporated into the lead frame 11 to detect the residual ink quantity (described later) and connected to the residual ink quantity detection means having a correction means for correcting the resistance at the main body side in accordance with the difference in the ink composition. The lead frame 11 is embedded in a casing made of, for example, resin, and the electrodes 12 correspond to the residual ink quantity detection electrodes 7, respectively, so that the residual ink quantity detection electrodes 7 are exposed into the absorbent member 6-1 to measure the ink resistance value, for example, between the electrodes 7a and 7b thereby detecting the residual ink quantity.
Next, the concrete method for detecting the residual ink quantity will be explained. When the amount or quantity of the ink in the ink tank 9 is reduced by consuming the ink in the ink tank 9 during the recording or printing operation and/or the ink recovery operation, the quantity of the ink included in the absorbent member 6-1 is also reduced, with the result that small bubbles are introduced into the absorbent member to gradually increase the electrical resistance between the electrodes 7a and 7b. Consequently, it is possible to detect the fact that the residual ink quantity reaches its lower limit, by detecting the reduction of the current between the electrodes. By monitoring the value of such current, it is possible to know the relation between the residual ink quantity l and the resistance of the ink R (between the electrodes). In FIG. 2, the curves A, B, C and D show the difference in the ink colors (the difference in the dyne), and the curves A, B, C, and D and E correspond to black ink (dyne density of 3.0%), red ink (dyne density of 2.5%), blue ink (dyne density of 2.5%), green ink (dyne density of 2%) and fresh tint ink (dyne density of 2.5%), respectively.
As seen from FIG. 2, since the respective volume resistance of the ink varies in accordance with the color thereof, in the case a detection lamp is turned on by activating the residual ink quantity detection means whenever the same resistance value R R is obtained between the electrodes 7a and 7b to detect the residual ink quantity therebetween, there will arise the difference in the residual quantity for each ink A, B, C and D, thus leading in the unfavorable result. In order to activate the residual ink quantity detection means when a certain predetermined residual quantity is reached for any ink A, B, C and D, it is desirable that the detection lamp regarding the residual quantity detection electrodes is turned on when the resistance value R R is obtained, by correcting the curves (FIG. 2) wholly by changing a correction resistance R C in the residual quantity detection circuit at a main body side shown in FIG. 3 to vary the difference in the resistance values between the inks A, B, C and D (for example, when the ink D having a low resistance value is used, by increasing the correction resistance R C to increase an apparent resistance (R=p·l/s; here, p is specific resistance, l is length, s is area) of the ink D. On the other hand, if the ink A having a high resistance value is used, the detection lamp may be turned on when the resistance value R R is obtained by correcting the curves wholly by decreasing the correction resistance R C to decrease the apparent resistance of the ink A. Further, as to the ink E having the different resistance value, similarly, the correction resistance R C may be changed to obtain the same residual quantity in response to the resistance value R R .
In this case, it is desirable to combine the residual quantity detection electrodes so that they are positioned to overlap in the gravity direction (The electrodes may be arranged along the oblique direction). FIG. 4 shows graphs indicating the resistance values measured in the vertical direction and in the horizontal direction. In the apparatus shown in FIG. 1, the resistance between the electrodes 7a and 7b may be detected. However, when the apparatus is arranged in the horizontal direction, the resistance between the electrodes 7b and 7c may be detected. Further, it should be noted that the distance between the electrodes 7 is shifted in the a direction when the distance is long or in the B direction when the distance is short. Each of the electrodes is preferably coated by high anti-corrosive layer such as SUS, gold-plating, platinum and the like. Incidentally, the distance between the electrodes varies in accordance with the structure of the absorbent member 6-1 of the head tip, and is preferably about 5-30 mm. In this case, the resistance of the ink has a value included in a range between a few tens of kQ. In the printing or recording apparatus for performing the printing operation by using such ink jet recording cartridge, the following test was carried out. That is to say, after the residual quantity detection lamp has once been turned ON, the ink C was replaced by the ink B. Thereafter, the correction resistance R C was manually varied to obtain a predetermined resistance value (in this example, while the correction resistance was varied manually, it may be varied automatically by using an appropriate means), and the residual quantity detection lamp was turned ON again. In this condition, the residual ink quantities in the two ink tanks were detected. As a result, it was found that there was substantially no difference in the residual quantities of the inks C and B in the ink tanks. However, when the ink is replaced by the different ink, it is desirable that the printing operation is started after the color of the old ink has been completely removed in the apparatus by repeating the recovery sequences regarding the new ink a predetermined number of times.
With the arrangement as mentioned above, it is possible to correctly detect the residual ink quantity by performing the same operation as mentioned above even if the ink tanks are changed on the way of the printing cycles.
Further, the residual ink quantity detection circuit adopted to the present invention may be constituted as shown in FIG. 5, since, when the circuit is always being energized, there is the danger of generating the bubbles due to the electrolysis of the ink. In this way, it is possible to perform one measurement for a short time, and also it is possible to completely avoid the generation of the bubbles due to the electrolysis of the ink by reversing the polarity for each measurement. The time required for one measurement is in the order of a few msec.
Further, by providing pins for discriminating or detecting the difference in the colors at the cartridge side and by communicating the pins with the main body after mounting the cartridge on the apparatus, the correction resistance may be changed.
Embodiment 2
FIGS. 6 and 7 are sectional view and perspective view, respectively, of an ink jet recording cartridge (the second embodiment) of the present invention. In this second embodiment, by providing the correction resistance R C in a detection portion at the main body side, the difference in the resistance of the ink due to the difference in the composition of the ink, i.e., the difference in mixture ratio of the solvent, is corrected, whereby the resistance output feature of the recording apparatus is standardized.
FIG. 6 shows a disposable ink jet recording cartridge. Also on this cartridge, the recording head tip 1 and the ink tank 9 can be removably mounted. Since this cartridge does not include an absorbent member in the ink tank, the head pressure of the tank must be maintained by the meniscus at the discharge openings of the discharging portion. Accordingly, this cartridge is used in the recording apparatus which permits recording in the horizontal direction. The mounting and dismounting of the cartridge can be performed in the same manner as the previously described first embodiment. The features of the cartridge of the second embodiment are the fact that the absorbent member is not included also at the recording head tip side and that the plate-like residual ink quantity detection electrodes 7A and 7B are arranged in an ink supplying chamber so as to detect the ink resistance between the electrodes 7A and 7B varied in accordance with a height h of the ink surface as showing in FIG. 7, thereby detecting the residual ink quantity.
For example, since the compositions of the optimum inks for the plain paper, coated paper, TP and the like are different from each other, the resistance values of these inks are also different from each other. As for such difference in the resistance value, by changing the correction resistance R C to always maintain the apparent resistance value to the constant value, it is possible to correctly detect the residual ink quantity even if the inks are changed.
In the illustrated embodiment, while the correction circuit was provided at the main body side, the correction may be effected by any circuit equivalent to the ink. Further, while the variable correction resistance was used, the correction may be effected by changing over resistors connected in series or in parallel to each other.
Next, an ink jet recording apparatus according to a third embodiment of the present invention will be explained.
Embodiment 3
FIG. 8 is a perspective view showing the third embodiment of the present invention. In this embodiment, a full color printing can be performed by using four ink jet recording heads. In order to perform full color printing, although four kinds of inks, i.e., cyan ink, magenta ink, yellow ink and black ink must be used, if four residual quantity detection means suitable to the respective ink colors are incorporated in each of four recording heads, the whole ink jet recording apparatus will be very expensive.
Accordingly, in the third embodiment, although the head side may be identical with those of the previous embodiments, the main body side is so designed that the signal values from the respective inks C (cyan), M (magenta), Y (yellow) and K (black) are corrected so that the detection lamp is turned ON when the residual quantities of the inks C, M, Y and K are the same. Since each ink tank can be replaced by a new one independently, the ink in the ink tank can be used at is maximum extent without the erroneous detection, thus permitting reduction of the running cost of the apparatus. Further, if a plurality of recording heads are used, it is possible to prevent damage of the heads due to the introduction of the bubbles into the discharging portions of the heads caused by the erroneous detection.
Embodiment 4
In this embodiment, by changing position of the electrode for residual quantity detection of the head side relative to the resistance change of ink resulted from difference of the ink i.e. dyne, the resistance correction based on distance is carried out to equalize the resistance output characteristic to the main body of printing apparatus.
FIG. 9 is a schematic view of the ink jet recording cartridge of disposable type according to the present invention.
This Embodiment 4 differs from the above Embodiment 1 in the construction that the pin-like electrodes 17a, 17b, 17c, 17d and 17e for ink residual quantity detection are provided on the recording head wall so that they are inserted into the ink absorbing member 6-1 made of porous or fiber like material. Explanation of another elements similar to the above Embodiment 1 is omitted by adding same or corresponding numerals for clarification.
Next, the concrete method of ink residual quantity detection of this embodiment will be explained.
In this embodiment, in order to achieve the residual quantity detection at a predetermined level for each of inks A, B, C and D, the resistance value difference of the inks A, B, C and D are changed by a changing apparatus. For example, in the case using the ink D of low resistance value, the distance between electrodes is selected long to thereby set the apparent resistance R=Pl/S (P: resistance ratio, l: length, S: area). Consequently, the curve is entirely corrected to turn on the residual quantity detection when the resistance value is R B . On the other hand, when using the ink A of high resistance value, the distance between electrodes is selected short to set the apparent resistance small. Consequently, the apparent resistance is corrected entirely so that the residual quantity detection will be operated when resistance value is R B . For the ink E of different resistance value variation, the position of electrodes are combined so that residual quantity becomes equal when the resistance is R B .
Preferably they are combined in upper-lower relation (oblique positioning is possible) with respect to the gravity direction. The graph obtained by measuring the resistance value in the vertical and horizontal directions relative to the gravity direction is shown in FIG. 10. Needless to say, the interval of detecting electrode is shifter to a direction or B direction as the distance becomes longer or shorter.
In the printing apparatus printing with this cartridge, the ink C is exchanged to ink B after turn on of the ink residual quantity detecting lamp, the electrode position is exchanged from 17a-17e to 17a-17d.
The lamp is turned on again, and residual ink quantity is detected to reach the result that there is found no difference therebetween. In connection with this, it is preferable to absorb and replace the ink by a constant recover sequence after the ink is replaced by another ink, and carry out printing after the color change has been completely finished. Furthermore, more accurate residual quantity detection becomes possible by adding the above process even in the course of ink tank exchange in the printing process.
Embodiment 5
The fifth embodiment of the present invention will be explained with reference to FIGS. 6 and 11.
In this embodiment, the resistance value change or variation due to difference of mixing ratio of the soluble agent, i.e. difference of composition of the ink is corrected by adding a correcting resistance R C at a detecting portion of the head cartridge, so that the resistance output characteristic to the main body of printer becomes equal.
In this embodiment, the residual quantity detection is effected by detecting the ink resistance between the electrodes 7A and 7B. However, by making the correcting resistance R C provided on the cartridge changeable relative to the resistance value variation due to the ink component, it becomes possible to keep the artificial resistance value constant and thereby accurate residual quantity becomes possible as for the ink exchange.
In the above embodiment, the simple correcting circuit is added to the head cartridge, but the correction can be made by a circuit equivalent to the ink. Additionally, although variable type correction resistance is used, it is possible to switch the resistances connected in serial or parallel. Switching can be effected manually or automatically.
Embodiment 6
FIG. 12 is a schematic view showing the sixth embodiment of the present invention. In this embodiment, the variation of ink resistance value accompanied by change of dyne density of ink is overcome by adding the correction resistance R C to the tank. The ink jet recording apparatus shown in FIG. 12 is constructed as a so-called permanent type having a lifetime as long as the main body of the apparatus, in which the recording head 1 mounted on the carriage (not shown) and the ink tank 9 is connected via an ink supplying tube 12. 14 shows detecting circuit for ink residual quantity provided the main body of apparatus.
This embodiment is constructed so that the bubble may not enter into the head by reducing the mounting parts of the head portion, increasing responsibility of the head itself and effecting the residual quantity detection at tank side. With such construction, bad or poor printing (non-discharge) resulting from bubble entry into the discharge portion due to erroneous detection can be prevented.
In the above-mentioned first, second and third embodiments, while the resistance value itself was corrected, the current value or voltage value generated in accordance with the change in the ink resistance value may be effected by correction relative to change.
Further, the following alterations or modifications may be adopted:
analog detection or digital detection may be used;
the changing of the correction resistance may be effected manually or automatically;
the recording head may be a disposable type head or a permanent type head having a lifetime equivalent to the main body of apparatus;
the electrodes may be arranged at the tank side or at the head tip side;
the ink may be accommodated in the tank with or without the absorbent member;
the correction is not necessarily performed in analog fashion and continuously, and, thus, may be changed digitally or may be changed with the use of any conversion table; and
the correction may be used for the detection of the residual ink quantity with the change in the ink resistance due to the difference in temperature of the ink caused by the change in ambient conditions.
Embodiment 7
This is an embodiment of ink jet recording apparatus in which and from which the head the cartridge of disposable type in which the recording head and ink tank are made integral each other.
In FIG. 13 showing cross section of the ink jet recording apparatus including the head cartridge according to the seventh embodiment of the present invention, reference numeral 101 shows a recording head chip corresponding to a main portion of the ink jet recording head, which head chip discharges the ink under movement opposing to a recording medium 120 corresponding to the recording signal. This constant current circuit to be explained in FIG. 16 later.
As mentioned above, since there occurs characteristic variation of among each of cartridges as shown in FIG. 15, if the threshold is determined simply as a point P as shown in FIG. 15, there occurs variation of residual ink quantity upon detection by ΔP (about 4 kg). This corresponds to 200 sheets (A4 size) with standard letter recording, and 40 to 60 sheets with image recording, which leads to deterioration of the detecting accuracy.
For overcoming the above defect, an area R where the recording becomes impossible is obtained by experiment as shown in FIG. 15. A recording chip is comprised of a print plate 103 having a base plate (heater board) on which the electric-thermal converting member (discharge heater) as discharge energy generating element and wiring parts therefor, and a line 110 of the discharge opening or liquid path corresponding to the discharge heater.
An ink tank 102 has an absorbing member 104 made of porous material and impregnated with predetermined quantity of ink, and a pair of electrodes for residual ink quantity are inserted into the absorbing member 104. The ink tank portion 102 and ink head chip are connected each other to construct the head cartridge, 107 is a porous filter provided between the ink tank and head chip and having an outer diameter which does not allow the air bubbles to pass easily.
For discharge energy generating element such as electric-thermal converting member disposed in the liquid path line 110 and generating energy for ink discharge and pin-like electrode 105 for residual ink quantity detection inserted into the absorbing member 104, the electrodes for realizing the electric connection therewith are gathered in the form of electrode line 111. The electrode line 111 is connected with a connector 112 of the recording apparatus main body side.
Upon recording by the recording apparatus of this embodiment, to the recording medium 120 conveyed in the P direction by supply roller pair 116 and discharge roller pair 119, a carriage scanning is carried out with the recording medium 120 being pressed onto a guide 118 by a sheet pressing rail 117 via a roller 121 of the carriage 122 which is scanned along a carriage axis 122.
In the present embodiment, the residual ink quantity detection in the ink tank 102 is basically carried out based on the resistance value between the electrodes 105. However, the residual ink quantity detection might not be carried out accurately by adopting the circuit construction such as resistance dividing method because the relation between residual ink quantity and resistance between electrodes may vary depending on current supplied between both electrodes, as shown in FIG. 14. Here, the residual ink detection is carried out by using the area selected as the threshold. In detail, the point Q is initially determined corresponding to an initial value of resistance between the electrodes of cartridge, then absence of residual ink is judged by a judging means when the point reaches to a resistance difference, thereafter sequence of the main body is properly controlled and alarm is displayed for an operator. For that, either data of the initial value or threshold (on the line Q) obtained therefrom is read into the non-volatile memory, and held as an information regarding to the cartridge mounted even when power is OFF.
FIG. 16 shows an example of a detecting circuit for residual ink quantity for achieving the above treatment or process, which includes a resistance determining means for determining the resistance between the electrodes 105, as described below. In FIG. 16, 100 shows the head cartridge of disposable type shown in FIG. 13, 200 shows a controlling portion of microcomputer type having for example a A/D convertor, 300 shows a non-volatile memory comprised of for example EEPROM or the like, 400 is a voltage converting circuit, and 500 shows a displayer and/or alarming portion for alarming the head cartridge to be exchanged when no residual ink is left.
FIG. 17 shows one example of treatment sequence according to the residual ink quantity detection by the controlling portion 200, and operation of the circuit shown in FIG. 16 is explained with reference to FIG. 17.
The controlling portion 200 makes a I/O port 1 in a residual ink quantity detecting timing (step 1), and makes a transistor Tr3 ON. As a result, a transistor Tr1 is made ON, and a transistor Tr2 will operate. Here, current Io that flows into the transistor is represented by
Io=(V.sub.Z -V.sub.BE)/R.sub.1
where V BE respresents voltage for base-emitter, and V Z is a Zener voltage.
The constant current thus obtained flows directly between both electrodes 105 in the ink tank of head cartridge. Accordingly, corresponding voltage is generated between the electrode 105. After waiting a predetermined time period (for example, one second) which is enough for stabilization thereof (step 5), this voltage is put into an A/D converter inputting terminal of the controlling portion 200 directly or via a voltage converting circuit 400 (step 7). Upon completion of A/D conversion (step 9), the controlling portion 200 makes I/O port and transistors Tr1-Tr3 OFF (step 11), and judges whether this sequence is started by mounting of new cartridge (step 13).
As shown in FIG. 15, since the curved condition can be recognized from data in which the ink is consumed, upon mounting of new cartridge, the controlling portion 200 calculates the threshold for no ink judgement suitable for the cartridge by A/D conversion value, i.e. initial data (step 15), and writes it into the non-volatile memory 300 (step 17).
In the succeeding detecting timing of residual quantity, the presence/absence of residual ink quantity can be judged by simply comparing the threshold calculated upon mounting of new cartridge and stored in the non-volatile memory 300 with the detected residual quantity (step 19). Thus, in the case when no ink residual quantity is detected, alarm is made to the operator to exchange the head cartridge (step 21), and effect the sequence to interrupt operation of various parts, or the like.
Incidentally, it is possible to store only the initial data upon mounting of new cartridge, and calculate the threshold in the succeeding process from the initial data.
As mentioned above, according to this embodiment, even when resistance variation between the electrodes can not be ignored upon detection of the residual ink quantity in the ink tank portion 102, residual quantity detection of high accuracy become possible by calculating the threshold level from which no ink is judged from the initial value of resistance between electrodes by constant current detection, and comparing the data with the substantial detecting data.
In addition, with regard to the change of characteristic resulted from difference of ink and composition, response can be made by adjusting the constant current value.
Embodiment 8
FIG. 18 shows another embodiment of the present invention. In FIG. 18, the member or means corresponded to that of FIG. 16 are represented by the same numerals.
In a head cartridge 100, the function corresponding to the switches (SW1 and SW2) is added for classifying the initial variation of the ink resistance. Actually, this can be effected by cutting the pattern formed on the printing plate by laser in the assembling process. In the disclosed embodiment, the information of classification is constructed by 2 bits, that is, to classify the variation into four ranks; an arbitrary predetermined bit number can be adopted, of course.
According to this embodiment, in addition to advantages obtained in the foregoing embodiment, the non-volatile memory 300 shown in FIG. 16 for storing the threshold or initial data become unnecessary since the classifying information is given from the head cartridge, which leads to simple construction of the apparatus and low cost for manufacture. A processing sequence substantially same that of FIG. 17 can be adopted in this embodiment, and the step corresponding to steps S15, S17 becomes unnecessary because the non-volatile memory 300 is not included.
In the above two embodiments, the present invention is applied to the ink jet recording apparatus using the head cartridge made by combining the recording head tip and the ink tank integrally. Of course, the head tip and ink tank may be made separately and the recording head tip need not be disposable.
In addition above explanation is made for the liquid jet recording apparatus of serial type in which the recording head is scanned relative to the recording medium to effect recording, the present invention can be applied to so-called multitype recording apparatus in which the discharge openings are arranged over the entire width of the recording medium, very effectively and easily. In other words, the present invention can be applied to the recording apparatus in which problem of variation of ink supplying source such as the ink tank occurs.
FIG. 19 is a perspective view showing one example of the ink jet recording apparatus according to the present invention, in which 1000 is a main body of apparatus, 1100 is a power source, and 1200 is an operational panel.
The present invention brings about excellent effects particularly in a recording head, recording device of the bubble jet system among the ink jet recording system.
As to its representative constitution and principle, for example, one practiced by use of the basic principle disclosed in, for example, U.S. Pat. Nos. 4,723,129 and 4,740,796 is preferred. This system is applicable to either of the so called on-demand type and the continuous type. Particularly, the case of the on-demand type is effective because, by applying at least one driving signal which gives rapid temperature elevation exceeding nucleate boiling corresponding to the recording information on an electricity-heat converters arranged corresponding to the sheets or liquid channels holding liquid (ink), heat energy is generated at the electricity-heat converters to effect film boiling at the heat acting surface of the recording head, and consequently the bubbles within the liquid (ink) can be formed corresponding one by one to the driving signals. By discharging the liquid (ink) through an opening for discharging by growth and shrinkage of the bubble, at least one droplet is formed. By making the driving signals into pulse shapes, growth and shrinkage of the bubble can be effected instantly and adequately to accomplish more preferably discharging of the liquid (ink) particularly excellent in response characteristics. As the driving signals, plus shapes such as those as disclosed in U.S. Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employment of the conditions described in U.S. Pat. No. 4,313,124 of the invention concerning the temperature elevation rate of the above-mentioned heat acting surface.
As the constitution of the recording head, in addition to the combination constitutions of discharging orifice, liquid channel, electricity-heat converter (linear liquid channel or right angle liquid channel) as disclosed in the above-mentioned respective specifications, the constitution by use of U.S. Pat. Nos. 4,558,333 and 4,459,600 disclosing the constitution having the heat acting portion arranged in the flexed region is also included in the present invention. In addition, the present invention can be also effectively made the constitution as disclosed in Japanese Patent Laid-Open Application No. 59-123670 which discloses the constitution using a slit common to a plurality of electricity-heat converters as the discharging portion of the electricity-heat converter or Japanese Patent Laid-Open Application No. 59-138461 which discloses the constitution having the opening for absorbing pressure wave of heat energy correspondent to the discharging portion.
Further, as the recording head of the full line type having a length corresponding to the maximum width of recording medium which can be recorded by the recording device, either the constitution which satisfies its length by combination of a plurality of recording heads as disclosed in the above-mentioned specifications or the constitution as one recording head integrally formed may be used, and the present invention can exhibit the effects as described above further effectively.
In addition, the present invention is effective for a recording head of the freely exchangeable chip type which enables electrical connection to the main device or supply of ink from the main device by being mounted on the main device, or for the case by use of a recording head of the cartridge type provided integrally on the recording head itself.
Also, addition of a restoration means for the recording head, a preliminary auxiliary means, etc. provided as the constitution of the recording device of the present invention is preferable, because the effect of the present invention can be further stabilized. Specific examples of these may include, for the recording head, capping means, cleaning means, pressurization or aspiration means, electricity-heat converters or another heating element or preliminary heating means according to a combination of these, and it is also effective for performing stable recording to perform preliminary mode which performs discharging separate from recording
Further, as the recording mode of the recording device, the present invention is extremely effective for not only the recording mode only of a primary stream color such as black etc., but also a device equipped with at least one of plural different colors or full color by color mixing, whether the recording head may be either integrally constituted or combined in plural number.
As mentioned heretofore, in the ink jet recording apparatus according to the present invention having correcting means for residual ink quantity, erroneous detection is hard to be generated, and the following qualities needed for ink jet recording apparatus can be realized without increasing cost.
(a) The same or common apparatus can be used for various kinds of ink for normal sheet, count sheet and TP.
(b) The same apparatus can be used for different kinds of color inks.
(c) It is possible to respond to change of using environment and continuing printing.
(d) Injury of the heating element due to erroneous detection and bad printing due to non-discharge can be prevented.
In the residual ink quantity detection apparatus detecting the residual ink quantity by resistance of the ink, the ink resistance is corrected at the main body of apparatus, recording head or tank portion, the resistance output characteristic can be kept in constant even if the ink components may vary. Furthermore, accurate residual quantity detection can be effected without exchange of the head even when plural kinds of inks are used. It is also possible to prevent bad printing due to erroneous detection. In detail, from the present invention, the ink jet recording head, ink tank and ink jet recording apparatus capable of effecting stabilized and high accuracy residual ink quantity detection with simple construction can be realized.
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An ink jet recording apparatus comprises a detachably mountable ink jet cartridge including an ink jet recording head for ejecting ink into a recording medium and an ink supply source containing ink for supply to the recording apparatus, which ink supply source has electrodes for passing an electric current through the ink in said ink supply source. A resistance-determining circuit determines a reference resistance between the electrodes by applying an electric current thereto when the ink jet cartridge is mounted to the apparatus and determines a test resistance between the electrodes by applying the same electric current thereto after a predetermined amount of recording. The reference resistance is used to calculate a threshold resistance, which is stored for comparison to the test resistance to judge whether or not the amount of ink in the ink supply source has dropped to a level unsuitable for recording.
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FIELD OF THE INVENTION
This invention relates to the field of buckets for use on a mechanical digging apparatus such as an excavator or grade-all having an articulatable boom, and in particular to a convertible bucket which may be mounted to such a boom.
BACKGROUND OF THE INVENTION
This invention generally relates to the field of mobile equipment for digging ditches, trenches, or the like.
As stated by Newman in his U.S. Pat. No. 4,691,455, which issued to Newman on Sep. 8, 1987 for Trenching Equipment With Hinged Side Plates, in construction and landscaping work it is frequently necessary to dig trenches with walls at angles which vary from the vertical, and many times it is desirable to form a trench wherein each of the side walls thereof are at different angles from the vertical. While there are many prior art devices to form trenches with angled side walls, many are inconvenient to use and, none provide any capability of varying the angle to suit the particular needs of a situation.
Newman thus provided a bucket for a trenching device which can form trenches with walls of varying slope. In particular, Newman discloses a trenching bucket having side plates which are adjustable so that trenches may be formed with walls at various slopes. In FIG. 9 of the Newman patent, the v-shaped trenching bucket is modified to have a floor, plate wherein the side plates are mounted by hinges along the outer edges of the floor plate. Two fan-shaped outer sections are fixed to or formed integral with the ends of the side plates and overlap a stationary, also fan-shaped section which is secured to a support frame. The two fan-shaped outer sections move with the side plates when the orientation of the side plates is adjusted by a corresponding pair of jacks. Newman indicates that the trenches formed by the bucket need not be symmetrical, rather, the side plates may be individually adjusted to provide the desired orientation for each wall of the trench being formed.
What is neither taught nor suggested by Newman is the use of a bucket having adjustable side walls which completely fold outwardly of the center section of the bucket so as to convert the bucket from a bucket which may be merely adjusted to adjust the angles of the walls of the ditches, trenches or the like being excavated, into a larger capacity wide-mouthed bucket, for example, one in which the lower floor of the wide-mouthed bucket is horizontal or almost horizontal across its entire width when placed on level ground, and is therefore well adapted for use in scooping large volumes of loose material.
SUMMARY OF THE INVENTION
This invention relates to an improvement in digging buckets such as used on the end of an arm of a backhoe, excavator, grade-all, tractor, and the like and, particularly, to buckets for such digging equipment in which the side plates or “wings” fold outwardly of the bucket into a substantially horizontal position to thereby provide a wide-mouth bucket
As is found in Newman's patent, an open top bucket is provided with adjustable side plates, herein referred to as wings, which are hinged so that the angle of the wings with respect to the vertical can be readily changed by pivoting or otherwise rotating the wings about a corresponding axis of rotation. The bucket may be provided with a base or floor plate and the wings are hingedly connected along the edges of the base or floor plate. The bucket is provided with a back wall which is preferably sectioned with the outer sections fixed to the trailing edge of the wings and fan-shaped in order to form a continuous back wall notwithstanding the inclination of the wings.
The bucket is provided with means to adjust the inclination of the wings, which may be manual actuators such as by means of individual jacks for each wing so that the angle of each can be separately manually adjusted as desired, or may selectively remotely-controlled actuators such as hydraulic cylinders and rods. That is, hydraulic control means may be provided to adjust the angle of the wings and the hand controls for such control means may be conveniently provided along with the other operational controls in the operator's console of the digging machine so that the angle of each wing can be independently, or collectively adjusted as necessary by the operator during digging without dismounting from the digging machine.
In summary then, the convertible bucket described herein may be characterized in one aspect as including a central support frame having an upper end and a lower end and defining an opening therebetween wherein the opening opens forwardly so that a distal end of the support frame is at the front of the bucket and the rear of the support frame is at the rear of the bucket. A pair of rigid wings are pivotally or otherwise rotationally mounted (collectively referred to herein as being pivotally mounted) on laterally opposite sides of the lower end of the support frame for rotation of each wing of the pair of rigid wings between their fully lowered position and their fully raised position. The pair of rigid wings define a wide-mouth width therebetween. In the fully lowered position each wing is substantially horizontal when the support frame is substantially vertical, so that, when the wings are both in their fully lowered position, the wide-mouth width is maximized. In a preferred embodiment a rigid or semi-rigid winglet (collectively referred to herein as a winglet) is mounted at a distal end of each wing so as to provide for containment of a load held in the bucket when at least one wing is in its fully lowered position.
Each winglet may include a longitudinally oriented fence having opposite forward and rear ends. The distal end of each wing each has a longitudinal dimension which extends a longitudinal distance. Each winglet may extend along substantially the entire length of the longitudinal dimension of the distal end of its corresponding wing. Advantageously the winglets each extend from the wings so as to be upstanding from the wings when the wings are in their fully lowered position. In one embodiment, such as illustrated by way of example, the winglets are substantially rectangular. This is not intended to be limiting as other plan form shapes would also work, for example, semi-elliptical, etc. In such an embodiment for example, each winglet has a height dimension which is perpendicular to the winglet's longitudinal dimension. Each wing has a corresponding width dimension which, when measured flush on each wing, is perpendicular to the longitudinal dimension of its winglet. The ratio of height dimension of each winglet to the width dimension of each wing may be in the range of 1:10 to 1:3. Alternatively the range may be is 1:5 to 1:3. In some embodiments the height dimension of each winglet is between 15 and 30 percent of the width dimension of the corresponding wing. The higher the height dimension of each winglet, the lower the ratio, and the greater the load carrying capacity of the wide-mouth bucket when the wings are in their fully lowered position.
In a further preferred embodiment, each wing has the same shape and the same dimensions as the other wing in the pair. For example both wings may be identical. So too, each winglet may be identical. For example, the winglets may have the same dimensions and each winglet may be substantially planar, although, again, this is not intended to be limiting as the winglets may be curved in either or both of horizontal and vertical planes.
In their fully lowered position the pair of rigid wings may be substantially co-planar. As used herein, substantially co-planar is meant to include completely flat, as well as embodiments where the wings are dished or concave to a small extent so that, collectively, the pair of wings when fully lowered form the profile of a “smile” on the front, lower surface of the wide-mouthed bucket. Thus in their fully lowered position, the pair of rigid wings may form a continuously smoothly concave lower surface of the bucket.
In some embodiments the forward end of each winglet coincides with the front of the bucket, and the rear end of each winglet coincides with the rear of the bucket. Also, each winglet may form an included angle relative to its corresponding wing. The included angle may be in the range of 90-135 degrees. In some embodiments the range may be smaller, for example: 90-120 or 100-110 degrees.
When in the fully raised portion, the distal ends of the wings may be advantageously adjacent the upper end of the support frame. The winglets may be substantially flush along the upper end of the support frame.
The lower end of the support frame may include a base plate having laterally spaced apart edges. The pair of rigid wings may be pivotally mounted to the edges of the base plate. At least one selectively controllable actuator may be provided for actuating the pair of rigid wings between their fully lowered and fully raised positions.
Further elements of, and the operation of, and further aspects of the invention will become apparent from the following detailed description when taken in conjunction with the accompanying exemplary drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is in right side perspective view, the convertible bucket as further described below with its wings almost completely lowered into their fully lowered position.
FIG. 2 is, in left side rear perspective view, the bucket of FIG. 1 with its wings in their fully lowered position.
FIG. 3 is, in right side rear perspective view, the bucket of FIG. 2 .
FIG. 4 is, in partially cut away right side top perspective view, the bucket of FIG. 3 with the right wing in its fully lowered position, and the left wing in its fully raised position.
FIG. 5 is the view of FIG. 1 showing one alternative embodiment of the bucket wherein, when the wings are in their fully lowered position, the wide-mouth bucket thereby formed has a lower surface which is dished or concave.
FIG. 6 is the view of FIG. 3 wherein the winglets are enlarged so as to have greater height when the wings are in their fully lowered position.
FIG. 7 is, in partially cut away right side top perspective view, the bucket of FIG. 6 with its wings in their fully raised position.
DETAILED DESCRIPTION OF THE INVENTION
As seen in the accompanying drawing figures wherein like characters of reference denote corresponding parts in each view, convertible bucket 10 includes a central support frame 12 supporting an upper housing 14 over a base 16 . An opposed-facing pair of hinged wings 18 are pivotally or hingedly mounted to base 16 so as to pivot between their fully raised position, for example as seen in FIGS. 4 and 7 , and the fully lowered position of FIG. 2 . Wings 18 pivot between the base 16 and the upper housing 14 .
Each wing 18 has a front edge 18 a , a lower edge 18 b , a rear edge 18 c and an upper edge 18 d . Winglets 20 are advantageously provided. Winglets 20 are mounted to the upper edges 18 d of both wings 18 so as to be cantilevered therefrom, advantageously substantially along the full length of upper edge 18 d of each wing 18 , to thereby project upwardly when wings 18 are in their fully lowered position, and so as to lay flush along, or adjacent to, the sidewall 14 a on each side of housing 14 when wings 18 are in their fully raised position.
Central support frame 12 has an upper end 12 a and an opposite, lower end 12 b . Upper end 12 a may include housing 14 . Central support frame 12 may include forward and rear wedge-shaped plates 24 a and 24 b mounted to rear end 16 c of base 16 . A longitudinally extending support brace 24 d bisects each of the pairs of wedge-shaped plates 24 a and 24 b . Wedge shaped plates 24 a and 24 b may for example be spaced apart and parallel and form a cavity 24 c there-between. Sector-shaped rear walls 26 are mounted at their lower most edges 26 a to the corresponding rear edges 18 c of wings 18 . Rear walls 26 may extend orthogonally from wings 18 so as to extend their interior edges 26 b into cavity 24 c between wedge-shaped plates 24 a and 24 b on either side of brace 24 d . Rear walls 26 rotate in direction C as wings 18 rotate in direction A so as to house rear walls 26 within cavities 24 c.
Thus as wings 18 rotate in directions A as seen in FIG. 1 , they rotate about axis of rotation A′ on hinges 22 from their fully lowered position to their fully raised position. In either the raised or lowered positions, wings 18 allow bucket 10 to be used to dig or scoop in direction B. When wings 18 are fully or partially raised bucket 10 may be used for example to dig ditches or the like (and the slopes may be adjusted as done in the prior art) and when wings 18 are fully lowered or substantially fully lowered (for example as in FIG. 1 ), bucket 10 may be used as a wide-mouthed bucket for efficiently scooping and moving more voluminous loads.
In one embodiment, not intended to be limiting, rear walls 26 may be mounted to the rear edges 18 c of wings 18 by means of hinges 28 . In other embodiments, rear walls 26 are rigidly mounted to wings 18 .
Winglets 20 project from the distal ends or outer edges 18 d of wings 18 so as to form a load-holding fence along the wings' distal ends. As illustrated, but without intending to be limiting, winglets 20 may extend upwardly at an acute angle alpha relative to the horizontal plane x. Thus the included angles between the wings and corresponding winglets are 90 degrees or greater. In the embodiment of FIGS. 2 and 3 , wings 18 and base 16 substantially lie in plane x when wings 18 are in their fully lowered position. Angle alpha is such that winglets 20 provide a fence along the laterally opposite sides of bucket 10 when bucket 10 is in its wide-mouthed orientation, that is, when wings 18 are fully lowered. Winglets 20 thereby assist in holding the load (shown in dotted outline as load 30 ) which has been scooped or gathered into the bucket, for example a load of earth, sand or gravel, so as to thereby increase the volume of the load that may be held and carried within bucket 10 in its wide-mouthed orientation. The fence function provided by winglets 20 inhibit the load 30 spilling off the distal ends of wings 18 , that is spilling off outer edges 18 d . The winglets may provide a shorter fence as seen in FIGS. 1-5 , or may provide a fence with greater height as seen in FIG. 6 , the latter providing a greater capacity for the bucket.
Actuators 32 , which may for example be hydraulic actuators, are pivotally mounted to rear edges 18 c of wings 18 by means of hinges or pivot joints 34 . Actuators 32 may be contained within an actuator housing 36 , illustrated by way of example as covering the upper ends of actuators 32 . As seen in FIG. 7 , the upper ends of actuators 32 are pivotally mounted by means of hinges or pivot joints 38 at an apex formed by the upwardly and inwardly inclined pair of actuators 32 . The lower hinges or pivot joints 34 may be protected by rearwardly extending flanges such as rearwardly extending flanges 18 e extending rearwardly, and in a substantially coplanar relationship with, wings 18 , and rearwardly extending flange 16 a extending rearwardly, and substantially coplanar relationship with, base 16 .
In the fully raised position seen in FIGS. 4 and 7 , the outer edges 18 d of wings 18 abut against and along the lower-most edges of sidewalls 14 a of upper housing 14 and winglets 20 are flush against or adjacent and substantially parallel to sidewalls 14 a.
Winglets 20 may be sized to fit snuggly onto, so as to overlay, sidewalls 14 a . The flush mounting of winglets 20 onto sidewalls 14 a assists in stabilizing wings 18 and to help relieve bending moments acting on hinges 22 when the bucket is being used to excavate hard or rocky ground. Winglets 20 may include raised surfaces (not shown) which releasably mate into cut-outs 14 b in sidewalls 14 a to further assist in releasably locking the winglets 20 , and thus also supporting wings 18 , in their fully raised positions.
In FIG. 7 , the upper and lower surfaces of housing 14 have been removed to show, respectively, actuator 40 and the upper-most end of brace 24 d . Actuator 40 is pivotally mounted on pivot joint 42 for rotation about vertical axis of rotation D. Actuator 40 rotates about axis D as extension or retraction of actuator rod 40 a in direction E causes cam follower 44 to follow the curve in direction F along the arcuate slot 46 shown in dotted outline. Slot 46 is formed in the upper wall 14 b of housing 14 . As seen in FIG. 4 , cam follower 44 is mounted to the bottom surface of hanger plate 48 . Hanger plate 48 is pivotally mounted for rotation in a plane horizontal to upper wall 14 b by means of a pivot joint 50 shown in dotted outline in FIG. 4 for rotation in direction F about vertical axis of rotation G. Hanger plate 48 is thus rotated about pivot joint 50 and axis G by the extension and retraction of rod 40 a of actuator 40 . Thus as seen in FIG. 4 , with rod 40 a fully retracted, plate 48 is fully rotated to the right hand side of bucket 10 which in FIG. 4 corresponds to the side of bucket 10 shown with one lowered wing 18 .
Ears 52 are rigidly mounted down onto plate 48 so that, with ears 52 also mounted to the distal end of the arm (not shown) of an excavator, rotation of plate 48 about axis of rotation G or the like will rotate bucket 10 relative to the excavator arm. Thus an operator selectively controlling actuator 40 thereby selectively controls the rotation and positioning of bucket 10 about axis G relative to the excavator arm. The rotating top or plate 48 thus creates an adjustable or variable offset which gives an operator the ability to move his digging/trenching machine toward or away from the ditch/trench bottom while adjusting the angle so as to always dig straight along the ditch/trench. Conventionally, often obstacles will prohibit the operator from appropriate or optimally positioning the machine requiring the operator to move toward or away from the bottom of the ditch/trench as the operator digs. As used herein the term excavator is intended to include heavy equipment which operates buckets at the end of actuable arms so as to include excavators, Grade-alls™ back hoes, tractors etc.
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A convertible bucket includes a central support frame. A pair of rigid wings are rotationally mounted on laterally opposite sides of the lower end of the support frame for rotation of each wing between their fully lowered and raised positions. The pair of rigid wings define a wide-mouth width therebetween. In the fully lowered position each wing is substantially horizontal when the support frame is substantially vertical, so that, when the wings are both in their fully lowered position, the wide-mouth width is maximized. A winglet may be mounted at a distal end of each wing so as to provide for containment of a load held in the bucket when at least one wing is in its fully lowered position.
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This is a division of application Ser. No. 560,062 filed Mar. 20, 1975, now U.S. Pat. No. 3,972,898.
BACKGROUND OF THE INVENTION
The commercial feasibility of processes for the preparation of medicinally valuable steroids depends, in the main, upon the availability and the cost of the starting materials. For example, in the synthesis of 19-norsteroids 3 described in U.S. Pat. No. 3,692,803, issued Sept. 9, 1972, ##STR1## the commercial viability of the process depends upon the cost and availability of the bicyclic unsaturated ketone 1 and the ethylenedioxy-beta-ketoester 2, the starting materials. A process for the preparation of 6,6-methylenedioxyheptan-2-one 5, the precursor of the beta-ketoester 2, ##STR2## was disclosed in U.S. Pat. No. 3,767,677, issued Oct. 23, 1973. This process involved the ketalization of one of the two symmetrically situated keto groups of 4, and even though it was unexpectedly found that selective ketalization occurred in the presence of excess alkylene glycol, a minor amount of the diketal 6 was formed, in addition to the desired predominant monoketal 5. The formation of the diketal 6 necessitated a costly, inefficient and inconvenient separation step involving the formation of the bisulfite addition product of the monoketal 5, separation of the minor diketal 6 by extraction, hydrolysis of the bisulfite addition product to the major monoketal 5, hydrolysis of the diketal 6 to the dione 4 and recyclization of the dione 4 through the ketalization process. The economics of the process for the preparation of 7,7-ethylenedioxy-2-oxo octanoic acid ethyl ester 2 would be substantially improved and the availability of these steroid starting materials would be materially increased if a process for the preparation of the monoketal 5, eliminating the costly, inefficient and inconvenient bisulfite separation and recyclization steps of the process described in the aforementioned patent was available. The present invention describes a process which avoids the bisulfite separation and recyclization steps.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a novel, efficient and inexpensive process for the preparation of 6,6-alkylenedioxyalkan-2-ones. More particularly, the present invention relates to an efficient, commercially feasible method for the preparation of 6,6-alkylenedioxyalkan-2-ones comprising the steps of condensing a lower-alkyl vinyl ketone with a lower-alkyl acetoacetate to form a 3-lower-alkoxycarbonylalkan-2,6-dione, selectively ketalizing the 2-keto group to form a 3-lower alkoxycarbonyl-6,6-alkylenedioxyalkan-2-one and saponifying and decarboxylating the 3-lower-alkoxycarbonyl group to form the desired 6,6-alkylenedioxyalkan-2-one.
As used throughout the specification and appended claims, the term "alkyl" denotes a straight or branched saturated hydrocarbon radical, such as methyl, ethyl, iso-propyl, tert.-butyl, hexyl, isooctyl and so forth and the term "lower" refers to the numerical range of 1 to 8.
In the formulas presented herein, substituents attached to the alkylenedioxy ring system may be in either the cis- or the trans- configuration, i.e., the substituents may be on the same side or on opposite sides of the average plane of the ring system. For example, the substituent designated R 1 may be in either the cis- or trans- configuration with respect to the spatial configuration of the substituent designated R 2 and the alkoxycarbonylalkanone side-chain.
Those compounds of the process of the present invention lacking an element of symmetry exist as optical antipodes and in the corresponding racemic forms. The present invention comprehends all possible optical isomers and racemic forms thereof. The formulas of the compounds of the process of the present invention shown herein are meant to include all possible isomeric and optical forms of the compounds depicted.
The process of the present invention for the preparation of 6,6-alkylenedioxyalkan-2-ones of formula 11 is illustrated in the Reaction Scheme.
In the first step of the process, an alkyl vinyl ketone of formula 7 is condensed with an alkyl acetoacetate of formula 8 to afford a 3-alkoxycarbonylalkan-2,6-dione of formula 9. The condensation reaction is generally performed in a lower-alkanol, such as methanol, ethanol or tert.-butanol containing a catalytic amount of the corresponding alkali metal alkoxide, such as sodium ##STR3## or potassium methoxide, ethoxide or tert.-butoxide, at a reaction temperature of about 0° to about 30° C, employing about equimolar amounts of the reactants 7 and 8. A solution of about 2% sodium ethoxide in absolute ethanol is the preferred reaction medium and a temperature of about 20° to 25° C is the preferred reaction temperature. The relative molar amounts of the alkyl vinyl ketone 7 and the alkyl acetoacetate 8 are not critical. About equimolar amounts of the reactants 7 and 8 are preferred to avoid possible purification problems in subsequent steps.
A closely related procedure for the condensation of methyl vinyl ketone and ethyl acetoacetate was described in Chemische Berichte, 81, 197 (1948).
As reported in U.S. Pat. No. 3,767,677, treatment of heptan-2,6-dione with the requisite 3- or 6-molar excess of an alkylene glycol affords, in addition of a major amount of the desired monoketal 5, sufficient diketal 6 to necessitate expensive and laborious bisulfite separation and recyclization steps. It has now been found unexpectedly that the separation and recyclization steps of the prior process can be voided by the selective ketalization of the 6-keto group of a 3-alkoxycarbonylalkan-2,6-dione of formula 9 to a 3-alkoxycarbonyl-6,6-alkylenedioxyalkan-2-one of formula 10 in sufficient purity to be useful in the subsequent steps of the instant process without a further bisulfite purification.
The selective ketalization of 3-alkoxycarbonylalkan-2,6-diones of formula 9 is performed by treatment with an alkylene glycol of formula 13 ##STR4## wherein R 1 and R 2 are hydrogen or lower alkyl and n is 0 to 2 in a suitable inert organic solvent containing an acid-catalyst at a reaction temperature of about 0° to about 30° C to afford 3-alkoxycarbonyl-6,6-alkylenedioxyalkan-2-ones of formula 10. Suitable inert organic solvents include, for example, aromatic solvents, such as benzene, toluene, xylene and the like. Benzene is the preferred solvent for the selective ketalization step.
Among the acid-catalysts which have been found to be useful in the ketalization step are sulfuric acid and aromatic sulfonic acid derivatives thereof, such as methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid and the like. Sulfuric acid is the preferred acid catalyst.
While reaction temperatures within the range of about 0° to about 30° C are not critical, reaction temperatures above 30° C in the ketalization step are to be avoided to suppress undesired diketal formation. A reaction temperature of about 0° C is preferred.
The final step of the process of the present invention for the preparation of 6,6-alkylenedioxyalkan-2-ones of formula 11 involves alkaline hydrolysis of the alkoxycarbonyl group of compounds of formula 10, followed by acidification and decarboxylation of the resultant unstable beta-ketoacid of formula 10 wherein R 1 , R 2 and n are as hereinbefore defined and R 3 is hydrogen. This step of the process is performed by treatment of beta-ketoesters of formula 10 with an aqueous solution of an alkali metal hydroxide, such as sodium or potassium hydroxide, to form the alkali metal salts of the beta-ketoacid of formula 10 wherein R 1 , R 2 and n are as hereinbefore defined and R 3 is an alkali metal, which are then treated with a suitable acid and an inert solvent, and finally heated at about 50° to about 100° C for about 30 minutes to about 1 hour to complete the decarboxylation.
Suitable inert solvents for the acidification of the alkali metal salts of the beta-ketoesters of formula 10 are water, lower alkanols and mixtures thereof. Water is the preferred inert solvent.
Acids suitable for the acidification of the alkali metal salts of the beta-ketoesters in the final step of the process of the present invention include weak organic aliphatic and aromatic acids, such as carbonic, acetic, propionic, oxalic, malonic, fumaric, citric, benzoic, phthalic, naphthanoic and the like, and weak inorganic acids, such as phosphorous, sulfurous, boric and the like. Carbonic acid is preferred. The reaction temperature necessary to complete the decarboxylation is not critical. The decarboxylation proceeds at a convenient rate between temperatures of about 50° to about 100° C and at a most convenient rate at steam bath temperatures. The decarboxylation time, on the other hand, is critical. Decarboxylation times of about 1 hour are preferred. The yield of the 6,6-alkylenedioxyalkan-2-ones of formula 11 decreases rapidly with longer reaction times.
While acidification of alkali metal salts of the beta-ketoacids of formula 10 promotes the decarboxylation of the salts, it is not necessary for the practice of the invention. Heating aqueous solutions of the salts within the afore-mentioned temperature range also results in decarboxylation to the monoketals of formula 11. As in the case of acidification, the decarboxylation time appears to be critical. Decarboxylation times greater than about 1 hour give rise to reduced yields and are to be avoided.
While the process of the present invention for the preparation of 6,6-alkylenedioxyalkan-2-ones may be carried out stepwise as delineated in the Reaction Scheme and immediately preceding description, the process is advantageously performed on a commercial scale without isolation of the intermediate 3-alkoxycarbonylalkan-2,6-diones and 3-alkoxycarbonyl-6,6-alkylenedioxyalkan-2-ones of formulas 9 and 10, respectively, i.e., as a one-pot process. This process not only enjoys all of the economic and practical advantages inherently associated with a one-vessel process, but as already stressed, obviates the uneconomical and inconvenient bisulfite purification step of the prior process described in U.S. Pat. No. 3,767,677.
The 3-alkoxycarbonyl-6,6-alkylenedioxyalkan-2-ones of formula 10 of the present invention are useful as intermediates for the preparation of 6,6-alkylenedioxyalkan-2-ones of formula 11, which in turn are useful for the preparation of 1-alkoxycarbonyl-6,6-alkylenedioxyalkan-2-ones of formula 12. The beta-ketoesters of formula 12 are employed as intermediates in the total synthesis of steroids having therapeutically valuable properties.
EXAMPLES
The following examples are for illustrative purposes only and are not to be construed as limiting the invention described herein in any way whatsoever.
EXAMPLE 1
Preparation of 5-(2-Methyl-1,3-dioxolan-2-yl)-2-pentanone (11, R, R 1 , R 2 are hydrogen and n is 0)
Methyl vinyl ketone (freshly distilled and stabilized with a trace of hydroquinone, 70 g, 1.0 mole) was added dropwise to a stirred solution of ethyl acetoacetate (130 g, 1.0 mole) and sodium ethoxide and absolute ethanol, prepared from sodium (0.5 g, 22 mmoles) and absolute ethanol (10 ml) 20°-25° C over a 30-minute period. After stirring at room temperature for 30 minutes, the reaction mixture was cooled in an ice bath and benzene (800 ml), ethylene glycol (800 g, 12.8 moles) and conc. sulfuric acid (96-98%, 15 ml) was added. The reaction mixture was stirred at the ice-bath temperature overnight. The layer was separated and the lower layer was extracted with benzene. The benzene extract was combined with the upper benzene layer of the reaction mixture and a solution of sodium hydroxide (42 g, 1.05 moles) in water (750 ml) was added to the combined benzene extracts, and the two-phase system was stirred vigorously at room temperature for 2 hours. The layers were separated and a fresh solution of sodium hydroxide (20 g, 0.5 mole) was added to the benzene layer. The two-phase system was stirred vigorously at room temperature for 2 hours and the layers were separated. Finely crushed dry ice (80 g) was added to the combined aqueous phases and the solution was heated on a steam bath for 1 hour with stirring. The mixture was allowed to cool to room temperature and, after the addition of sodium chloride (100 g), was extracted with benzene (3 × 300 ml). The combined extracts were dried over anhydrous sodium sulfate. The drying agent was removed by filtration and the filtrate was concentrated under reduced pressure. Distillation of the residual oil gave 106 g (61%) of the alkylenedioxyalkanone as a colorless oil, boiling point 73°-78° C (0.15 mm).
The purity (98%) of the product was established by gas-liquid chromatographic analysis.
EXAMPLE 2
Preparation of 5-(2-Ethyl-1,3-dioxolan-2-yl)-2-pentanone (11, R is methyl, R 1 and R 2 are hydrogen and n is 0)
Ethyl vinyl ketone (11.4 g, 0.136 mole) was added dropwise over 75 minutes to a solution of ethyl acetoacetate (17.6 g, 0.112 mole) and 20% sodium ethoxide in ethanol (1.35 ml), cooled to 20° C. The reaction mixture was stirred at room temperature for 30 minutes. Benzene (120 ml), ethylene glycol (120 g, 1.9 moles) and conc. sulfuric acid (2.25 ml) were added consecutively to the reaction mixture maintained at 0° C by external cooling. The mixture was stirred at 0° C overnight. The layers were separated and the glycol layer was extracted with benzene (75 ml). The combined benzene layers were stirred with 2.6% aqueous sodium hydroxide solution (310 ml) overnight at room temperature. The layers were separated and the aqueous phase was treated with dry ice (12 g) and the solution was heated at 85° C for 1 hour. The solution was allowed to cool to room temperature, sodium chloride (15 g) was added and the solution was extracted with benzene (3 × 150 ml). The combined benzene extracts were dried over anhydrous sodium sulfate, the drying agent was collected on a filter and the filtrate was concentrated under reduced pressure. Distillation of the residual oil gave 12.7 g (50%) of the monoketal as a colorless oil, boiling point 63°-65° C (0.15 mm).
EXAMPLE 3
Preparation of 5-(2,4-Dimethyl-1,3-dioxolan-2-yl)-2-pentanone (11, R and R 1 are hydrogen, R 2 is methyl and n is 0)
Methyl vinyl ketone (7.0 g, 0.100 mole) was added dropwise over 1 hour to a mixture of ethyl acetoacetate (13.0 g, 0.101 mole) and 20% sodium ethoxide in ethanol (1 ml), cooled to 20° C. The reaction mixture was stirred at room temperature for 30 minutes. Benzene (80 ml) and propylene glycol (99 g, 1.30 moles) were added consecutively. The two-phase system was cooled to 0° C, conc. sulfuric acid (1.5 ml) was added and the solution was stirred at 0° C for 2 hours. The layers were separated and the glycol layer was extracted with benzene. Aqueous sodium hydroxide solution (2%, 200 ml) was added to the combined benzene extracts and the mixture was stirred at room temperature overnight. The layers were separated and an additional 100 ml of 2% aqueous sodium hydroxide solution was added to the benzene layer. The two-phase system was stirred at room temperature for 1 hour and the layers were separated. Dry ice (9 g) was added to the combined aqueous phases and the solution was heated at 85° C for 1 hour. The solution was allowed to cool to room temperature, sodium chloride (15 g) was added and the solution was extracted with benzene (3 × 100 ml). The combined organic extracts were dried over anhydrous sodium sulfate, the drying agent was collected on a filter and the filtrate was concentrated under reduced pressure. Distillation of the residue gave 9.2 g (49%) of the monoketal as a colorless oil, boiling point 57°-61° C (0.15 mm).
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An improved process for the preparation of 6,6-alkylenedioxyalkan-2-ones starting from alkyl vinyl ketones and alkyl acetoacetates is disclosed. The 6,6-alkylenedioxyalkan-2-ones are useful as intermediates in the total synthesis of therapeutically valuable steroids.
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FIELD OF THE INVENTION
[0001] This invention relates to a control device for controlling lock-up of a torque converter.
BACKGROUND OF THE INVENTION
[0002] In a torque converter provided with a lock-up clutch, control of a front-rear differential pressure (lock-up differential pressure) of the lock-up clutch engages and releases the lock-up clutch. To shift the torque converter from a converter state to a lock-up state, the lock-up differential pressure gradually increases from a predetermined initial differential pressure. The torque converter shifts from the converter state to the lock-up state via a slip state. In the converter state the lock-up clutch is released, in the slip state the lock-up clutch slips, and in the lock-up state, the lock-up clutch is engaged.
[0003] In this lock-up clutch control, the real lock-up clutch differential pressure has scatter due to individual differences and time-dependent variations of the torque converter. JP2000-27986 published by the Japan Patent Office in 2000 discloses a prior art technique wherein learning control of the differential pressure is performed in order to correct the deviation of engagement timing due to this scatter.
SUMMARY OF THE INVENTION
[0004] However, in the aforesaid prior art, when lock-up is performed during coasting of the vehicle (when the accelerator pedal stroke is zero), learning is performed after decreasing the front-rear differential pressure of the lock-up clutch until a small slip occurs, and unless coasting of the vehicle is continued for a long time, the differential pressure learning value is not appropriate. Therefore, time was taken to complete learning.
[0005] Further, in the case of smooth lock-up where the accelerator pedal stroke is small (where the throttle valve has a low opening), the real differential pressure occasionally varies due to an oil temperature variation.
[0006] For example, if the real differential pressure is larger than a differential pressure command value due to scatter in the real differential pressure, the engine rotation speed will rapidly decrease, causing a shock due to early engagement, and the driver will experience discomfort. Conversely, if the real differential pressure becomes smaller than the differential pressure command value due to scatter in the real differential pressure, it takes a long time for lock-up to complete, and the fuel consumption rate will be impaired.
[0007] It is therefore an object of this invention to rapidly learn a differential pressure while taking an oil temperature variation into consideration, and to eliminate the deviation of engagement timing.
[0008] In order to achieve the above object, this invention provides a lock-up clutch control device which controls a lock-up clutch provided in a torque converter installed between an engine and a transmission. The lock-up clutch control device changes over between a converter state and a lock-up state of the torque converter according to a differential pressure command value relating to a differential pressure supplied to the lock-up clutch. The lock-up clutch control device comprises a differential pressure generating device which generates the differential pressure supplied to the lock-up clutch; input torque detection means which detects an input torque to the torque converter; and a controller. The controller is programmed to compute a real differential pressure based on the detected input torque upon completion of the engagement of the lock-up clutch; compute a learning value relating to a differential pressure deviation, based on the difference between the computed real differential pressure and differential pressure command value upon completion of the engagement of the lock-up clutch, and store the learning value; correct a present differential pressure command value based on the learning value; and send the corrected differential pressure command value to the differential pressure generating device.
[0009] The details as well as other features and advantages of this invention are set forth in the remainder of the specification and are shown in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a block diagram of a vehicle drive system comprising an automatic transmission according to this embodiment.
[0011] FIG. 2 is a block diagram showing a slip control performed by an AT (automatic transmission) controller.
[0012] FIG. 3 is a graph showing a differential pressure command value and a differential pressure deviation learning value LUprs_OFFSET, and showing a relation between a differential pressure command value and time.
[0013] FIG. 4 is a flowchart showing an example of a learning control performed by an AT controller.
[0014] FIG. 5 is a map showing a relation between the engagement capacity (transmitted torque) of a lock-up clutch, and a differential pressure.
[0015] FIG. 6 is a schematic diagram showing a learning value storage region of a memory.
[0016] FIG. 7 is a time chart showing an engagement control state of the lock-up clutch. FIG. 7A is a time chart showing lock-up ON/OFF. FIG. 7B is a time chart showing a differential pressure command value. FIG. 7C is a time chart showing an engine rotation speed and input shaft rotation speed.
[0017] FIG. 8 is a time chart showing release control of the lock-up clutch. FIG. 8A is a time chart showing lock-up ON/OFF. FIG. 8B is a time chart showing the differential pressure command value. FIG. 8C is a time chart showing the engine rotation speed and input shaft rotation speed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] An automatic transmission comprising a torque converter 5 and a transmission 4 is connected to an engine 3 . The torque converter 5 is provided with a lock-up clutch 6 , the lock-up clutch 6 being in a lock-up state (engaged state) or unlocked state (release state) according to the vehicle running state.
[0019] The torque converter 5 houses the lock-up clutch which rotates with a torque converter output element (i.e. turbine). When the lock-up clutch 6 is directly connected to a torque converter input element (i.e. impeller), the torque converter 5 enters a lock-up state wherein the input and output elements are engaged by the lock-up clutch 6 .
[0020] The lock-up clutch 6 responds to a differential pressure Pa—Pr between the torque converter apply pressure Pa and torque converter release pressure Pr on front and rear sides thereof. When the release pressure Pr is higher than the apply pressure Pa, the lock-up clutch 6 is released and the torque converter input and output elements are not directly connected. When the release pressure Pr is lower than the apply pressure Pa, the lock-up clutch 6 is engaged and the torque converter input and output elements are directly connected. The engaging force, i.e., the lock-up capacity (transmitted torque) of the lock-up clutch 6 , is determined by the differential pressure Pa-Pr. The engaging force of the lock-up clutch 6 increases and lock-up capacity increases, the larger the differential pressure is.
[0021] The differential pressure Pa-Pr is controlled by a lock-up control valve 7 known in the art. The lock-up control valve 7 is disclosed for example in U.S. Pat. No. 5,332,073 issued Jul. 26, 1994 to Iizuka, or U.S. Pat. No. 5,752,895 issued May 19, 1998 to Sugiyama et al.
[0022] In this embodiment, a lock-up solenoid valve 8 generates a line pressure Psol according to a duty signal DUTY, using a pump pressure Pp as an original pressure. The line pressure Psol acts on the lock-up control valve 7 . In the lock-up control valve 7 , the apply pressure Pa and release pressure Pr are mutually opposed. A spring pushing force is applied in the same direction as the apply pressure Pa, a spring pushing force is applied in the same direction as the release pressure Pr, and the line pressure Psol simultaneously acts in the same direction as the release pressure Pr. The lock-up control valve 7 determines the differential pressure Pa—Pr so that the oil pressures and spring forces balance each other. The lock-up solenoid valve 8 and lock-up control valve 7 form a differential pressure generating device which generates the differential pressure applied to the lock-up clutch.
[0023] An AT controller 1 comprising a microcomputer determines a duty signal DUTY according to the vehicle running state, and controls the differential pressure Pa—Pr via the lock-up solenoid valve 8 . The AT controller 1 comprises a microcomputer comprising a central processing unit (CPU), random access memory (RAM), read-only memory (ROM), input and output (I/O) interface and timer. The read-only memory (ROM) may be a programmable ROM.
[0024] The AT controller 1 receives signals which indicate a vehicle running state and a driver state. These signals are for example an input shaft rotation speed Ni of the transmission 4 detected by an input shaft rotation sensor 16 (first rotation speed sensor), a pump impeller rotation speed Np detected by an impeller rotation sensor 11 (second rotation speed sensor), an accelerator pedal stroke APO (or opening TVO of a throttle valve) detected by an accelerator pedal stroke sensor 14 , an oil temperature Tatf detected by an oil temperature sensor 12 and a vehicle speed VSP detected by a vehicle speed sensor 13 . The input shaft of the transmission 4 coincides with the output shaft of the torque converter 5 , and the input shaft rotation speed to the transmission 4 is equivalent to the output shaft rotation speed from the torque converter 5 . The pump impeller rotation speed Np is equivalent to the input rotation speed (which is equal to an engine rotation speed Ne) to the torque converter 5 . The AT controller 1 receives the engine rotation speed Ne and engine torque Te from an engine controller 2 . The engine torque Te may be an engine torque command value set by the engine controller 2 . With these signals, the AT controller 1 performs the engagement/release of the lock-up clutch 6 , and performs slip control. The engine rotation speed Ne is detected by an engine rotation speed sensor 15 , and is inputted into engine controller 2 .
[0025] The engine controller 2 comprises a microcomputer comprising a central processing unit (CPU), random access memory (RAM), read-only memory (ROM) and input/output (I/O) interface. The engine controller 2 and AT controller 1 may be integrated in one controller.
[0026] The AT controller 1 performs a smooth lock-up control according to the vehicle running state. The smooth lock-up control engages the lock-up clutch 6 from a converter state via a slip state and is performed for example when variation in the accelerator pedal stroke APO is small and the vehicle speed VSP increases gradually.
[0027] In this embodiment, when engagement of the lock-up clutch 6 is complete, the AT controller 1 learns a deviation of the real differential pressure from a differential pressure command value P_ref upon completion of the engagement of the lock-up clutch, and on the next occasion lock-up is performed, corrects the differential pressure command value LUprs_slp using this learning value.
[0028] FIG. 2 is a control block diagram showing an outline of slip control (or differential pressure control of the lock-up clutch) according to this embodiment, and shows a part of the functions of the AT controller 1 . The control routine shown in FIG. 2 is repeatedly performed every control period. Each unit may represent a command set performed by the controller, or an electrical circuit. The AT controller 1 determines ON/OFF of lock-up based on running conditions such as vehicle speed. During engagement/release of the lock-up clutch after lock-up ON/OFF changes, slip control is performed.
[0029] A slip control unit 21 calculates a slip rotation speed Nslp from the difference of the pump impeller rotation speed Np and input shaft rotation speed Ni (output rotation speed from the torque converter 5 ). That is, Nslp=Np—Ni. The slip control unit 21 outputs a slip command value LUprs_slp which is the differential pressure command value which may increase as the slip rotation speed Nslp decreases. For example, in a feedback/feedforward control, the slip command value LUprs_slp is determined such that the slip rotation speed Nslp converges to a target value set based on the vehicle operating state.
[0030] A differential pressure offset learning unit 22 calculates a differential pressure deviation learning value LUprs_OFFSET (=P_learn(Tai)) according to the oil temperature Tatf as described later. The initial value of the corrected differential pressure command value LUprs is computed by adding the differential pressure deviation learning value LUprs_OFFSET to the initial slip command value LUprs_slp (initial value of LUprs=initial value of LUprs_slp+LUprs_OFFSET).
[0031] A signal conversion unit 23 (signal generator) converts the corrected differential pressure command value LUprs to the duty signal DUTY, and sends it to the lock-up solenoid valve 8 . As shown in FIG. 3 , an increment corresponding to a predetermined slope α is added to LUprs_slp every control period of the slip control shown in FIG. 2 (LUprs_slp=LUprs_slp+α) so that the corrected differential pressure command value LUprs gradually increases every control period during slip control. After the differential pressure command value LUprs_slp has increased for a predetermined period Tx, it is finally set to a predetermined differential pressure command value P_ref (differential pressure upon completion of engagement). The differential pressure command value P_ref upon completion of engagement increases according to the input torque Te (in other words, the engine torque Te) to the torque converter 5 .
[0032] A typical learning control routine performed by the AT controller 1 will now be described referring to the flowchart of FIG. 4 . This control routine is repeatedly performed at a predetermined control period (e.g., several milliseconds) after smooth lock-up has started.
[0033] First, in a step S 1 , a learning prohibition flag showing that the present running state satisfies learning prohibition conditions is set based on the detection values read from the sensors.
[0034] The learning prohibition conditions are as follows:
(1) The engine torque Te from the engine controller 2 is abnormal. (2) The engine torque Te is unstable. (3) The engine rotation speed Ne is sharply varying. (4) The input shaft rotation speed Ni is sharply varying. (5) The oil temperature Tatf lies outside a learning permission temperature range where learning is permitted. (6) The engine torque Te lies outside a learning permission engine torque range where learning is permitted. (7) The variation of the differential pressure command value LUprs is more than a predetermined variation.
[0042] If at least one of the conditions (1)-(7) is satisfied, the learning prohibition flag is set to 1, and if none of the conditions is satisfied, the learning prohibition flag is reset to 0.
[0043] The reason for setting the learning prohibition conditions (1),(2),(3) is to prohibit learning of the differential pressure deviation when the engine has stopped, when there is interference with communication or when the engine 3 is in a transient state (when the accelerator pedal is being depressed or released), and to calculate a differential pressure deviation learning value based on the engine torque Te received from the engine controller 2 in the steady state of the engine.
[0044] The reason for setting the learning prohibition condition (4) is that when the input shaft rotation speed Ni is sharply varying, the drive system inertia is added to the torque and a precise differential pressure deviation learning value cannot be obtained. When the input shaft rotation speed Ni the sharply varying, learning of the differential pressure deviation is prohibited.
[0045] The reason for setting the learning prohibition condition (5) is to prohibit learning at an extreme oil temperature Tatf above a preset upper limit T_MAX and at an extreme oil temperature Tatf below a preset lower limit T_MIN. The learning permission temperature range from the lower limit T_MIN to the upper limit T_MAX may be the temperature range wherein lock-up can be performed.
[0046] The reason for setting the learning prohibition condition (6) is that when the engine torque Te is very small or very large, the error in the engine torque Te sent from the engine controller 2 is large. Learning of the differential pressure deviation is prohibited in the engine torque range when this error is large.
[0047] The reason for setting the learning prohibition condition (7) is that when the variation rate of the differential pressure command value LUprs is equal to or greater than a predetermined value, the differential pressure command value itself is sharply varying. The variation rate of the differential pressure command value LUprs is obtained by calculating the difference between the present differential pressure command value LUprs and the differential pressure command value at a predetermined earlier time.
[0048] The setting or resetting of the learning prohibition flag is performed on the basis of the above learning prohibition conditions.
[0049] Next, in a step S 2 , it is determined whether or not the learning prohibition flag is 1. When the learning prohibition flag is 1, the control routine is terminated without performing learning of the differential pressure deviation. When the learning prohibition flag is 0, learning is permitted so the routine proceeds to a step S 3 .
[0050] In the step S 3 , the slip rotation speed Nslp is calculated from the difference of the pump impeller rotation speed Np and input shaft rotation speed Ni (Nslp=Np—Ni).
[0051] Next, in a step S 4 , the slip rotation speed Nslp is compared with a predetermined rotation speed (for example, 10 rpm), and it is determined whether or not the slip rotation speed Nslp is less than the predetermined rotation speed, i.e., whether or not engagement of the lock-up clutch 6 is complete.
[0052] When engagement of the lock-up clutch 6 is complete i.e., when the slip rotation speed Nslp is less than the predetermined rotation speed, the routine proceeds to a step S 5 . In the step S 5 , a differential pressure deviation estimation value P_error which is the estimated value of the deviation between the differential pressure command value P_ref and the real differential pressure, is computed upon completion of engagement. The current differential pressure command value LUprs_slp is the differential pressure command value P_ref upon completion of engagement P_ref.
[0053] The differential pressure deviation estimation value P_error is calculated based on an engine torque signal TrqENG received from the engine controller 2 , by: P_error=(|TrqENG|−β−α×P_ref)/α
[0054] Herein, TrqENG is the engine torque, β is a correction amount of the differential pressure command value LUprs for each oil temperature, a is the variation amount (slope) shown in FIG. 3 , and P_ref is the differential pressure command value when engagement is complete i.e., the differential pressure upon completion of engagement.
[0055] Alternatively, if the engagement capacity (transmitted torque) of the lock-up clutch 6 is Tlu, the relation Te=Tlu holds when smooth lock-up is complete. A linearly proportional relationship holds between the engagement capacity Tlu of the lock-up clutch 6 and the differential pressure, as shown by the map of FIG. 5 . Therefore, the real differential pressure (engagement completion differential pressure) P_lu upon completion of engagement of the lock-up clutch 6 can be obtained from the engine torque Te at that time by referring to the map stored in the memory. The difference between the real differential pressure P_lu upon completion of engagement and the differential pressure command value P_ref upon completion of engagement may be calculated as the differential pressure deviation estimation value P_error (P_error=P_ref-P_lu).
[0056] Next, in a step S 6 , it is determined whether or not the absolute value of the differential pressure deviation estimation value P_error is equal to or less than a predetermined limit value ERROR_SL. When the absolute value of the differential pressure deviation estimation value P_error exceeds the predetermined limit value ERROR_SL, it is an extremely large value due to a signal error, etc. Therefore, when the absolute value of the differential pressure deviation estimation value P_error exceeds the limit value ERROR_SL, learning of the differential pressure deviation estimation value P_error is prohibited, and the routine terminates.
[0057] When the absolute value of the differential pressure deviation estimation value P_error is less than the limit value ERROR_SL, the routine proceeds to a step S 7 where the oil temperature Tatf of the transmission 4 is read from the oil temperature sensor 12 .
[0058] Next, in a step S 8 , a storage location of the differential pressure deviation learning value is selected from learning value storage regions, based on the differential pressure command value P_ref and oil temperature Tatf when engagement of the lock-up clutch 6 is complete. The learning value storage regions are preset in the memory, as shown in FIG. 6 . In this embodiment, the learning value storage regions are represented by a matrix of three rows and three columns which respectively classify the range of oil temperature Tatf and the range of the differential pressure command value P_ref upon completion of engagement.
[0059] The range of the differential pressure command value P_ref upon completion of engagement is divided into three zones, i.e., a first differential pressure region (P_REF_MIN≦P_ref<P_REF_LO), a second differential pressure region (P_REF_LO≦P_ref<P_REF_HI) and a third differential pressure region (P_REF_HI≦P_ref≦P_REF_MAX). Herein, P_REF_MIN shows a differential pressure command value minimum, P_REF_MAX shows a differential pressure command value maximum, P_REF_LO shows a predetermined low differential pressure command value and P_REF_HI shows a predetermined high differential pressure command value. The relation P_REF_MIN<P_REF_LO<P_REF_HI <P_REF_MAX holds. The first differential pressure region defines the row in which the differential pressure deviation learning value P_errorLO for a small differential pressure command value P_ref ranging from P_REF_MIN to P_REF_LO, is stored. The second differential pressure region defines the row in which the differential pressure deviation learning value P_errorMID for a medium differential pressure command value P_ref ranging from P_REF_LO to P_REF_HI, is stored. The third differential pressure region defines the row in which the differential pressure deviation learning value P_errorHI for a large differential pressure command value P_ref ranging from P_REF_Hi to P_REF_MAX, is stored.
[0060] The region of the oil temperature Tatf is divided into three zones, i.e., a first oil temperature region (T_MIN≦Tatf<T_LO), a second oil temperature region (T_LO≦Tatf<T_HI) and a third oil temperature region (T_HI≦Tatf<T_MAX). Herein, T_MIN shows the lowest oil temperature, T_MAX shows the highest oil temperature, T_LO shows a predetermined low oil temperature and T_HI shows a predetermined high oil temperature. The relation T_MIN<T_LO<T_HI<T_MAX holds.
[0061] The first oil temperature region defines the column in which the differential pressure deviation learning value for a low oil temperature Ta0 ranging from T_MIN to T_LO, is stored. The second oil temperature region defines the column in which the differential pressure deviation learning value for a medium oil temperature Ta1 ranging from T_LO to T_HI, is stored. The third oil temperature region defines the column in which the differential pressure deviation learning value for a high oil temperature Ta2 ranging from T_HI to T_MAX, is stored.
[0062] As mentioned above, the location at which the differential pressure deviation learning value will be stored or updated is determined based on three regions (rows) of the differential pressure command value P_ref, and three regions (columns) of the oil temperature Tatf. The nine elements of the matrix, i.e., nine learning values, are represented by P_errorLO(Tai) (i=0,1,2), P_errorMID(Tai) (i=0,1,2) and P_errorHI(Tai) (i=0,1,2).
[0063] Next, in a step S 9 , the presently stored learning value is read as P_errorN from the selected learning value storage location selected in the step S 8 .
[0064] In a step S 10 , a new learning value is computed. First, a difference P_error-P_errorN between the differential pressure deviation estimation value P_error and the presently stored learning value P_errorN is calculated. Next, the median of the three values, preset limit value (+ΔLM) on the increase side, preset limit value (−ΔLM) on the decrease side and difference P_error−P_errorN, is calculated. The result of adding the presently stored learning value P_errorN to the median is set as a new learning value.
New learning value=P_errorN+mid (−ΔLM, P_error−P_errorN, +ΔLM)
[0065] In this way, the variation amount of the learning value on one learning occasion falls within the limits of +ΔLM and −ΔLM, and sharp fluctuation of the learning value is prevented.
[0066] Next, in a step S 11 , the storage location selected in the step S 8 is overwritten with the new learning value calculated in the step S 10 , and thus the learning value is updated at the storage location selected in the step S 8 .
[0067] Next, in a step S 12 , it is determined whether or not, in the row for the current updated learning value, there is a learning value for all of the columns Ta0-Ta2.
[0068] If there is a learning value in the whole oil temperature region of this row, the routine proceeds to a step S 13 . When at least one of the columns Ta0-Ta2 of this row has no learning value, the routine proceeds to a step S 14 .
[0069] In the step S 13 , the learning value P_learn(Tai) (=LUprs_OFFSET) used for slip control is set to the average value represented by the following formula:
P_learn(Tai)=(P_errorLO(Tai)+P_errorMID(Tai)+P_errorHI(Tai))/3(where i=1,2,3)
[0070] For each oil temperature, the learning value is averaged with respect to the differential pressure command value P_ref. Hence, large differences of the learning value for the same oil temperature can be prevented.
[0071] The average difference pressure learning value P_learn(Tai) according to the oil temperature Tatf is used as LUprs_OFFSET for slip control. In slip control, when the oil temperature Tatf is in the first oil temperature range (T_MIN≦Tatf<T_LO), the average difference pressure learning value P_learn(Ta0) is used. When the oil temperature Tatf is in the second oil temperature range (T_LO≦Tatf<T_HI), the average difference pressure learning value P_learn(Ta1) is used. When the oil temperature Tatf is in the third oil temperature range (T_HI≦Tatf<T_MAX), the average difference pressure learning value P_learn(Ta2) is used.
[0072] Next, in a step S 14 , processing to prevent learning errors is performed. Referring to FIG. 7 , when the lock-up clutch completely engages at a time Tb− which is earlier than a lower limit T_LU_MIN, and when the lock-up clutch completely engages at a time Tb+ which is later than an upper limit T_LU_MAX, it is determined that the differential pressure learning value LUprs_OFFSET has shifted due to learning error, so the present learning value P_learn(Tai) is reset to zero, and initialized so that learning can start again. The scheduled time Tb at which engagement of the lock-up clutch 6 completes is a value obtained by adding a predetermined period Tx to an engagement start time Ta. The lower limit T_LU_MIN is smaller than the scheduled time Tb by a predetermined value, and the upper limit T_LU_MAX is larger than the scheduled time Tb by a predetermined value. The predetermined period Tx may range from 1 to 5 seconds.
[0073] The effect of this embodiment will now be described.
[0074] According to this embodiment, a learning value relating to the differential pressure deviation is found from the difference of the real differential pressure (engagement completion differential pressure) and differential pressure command value when engagement of the lock-up is complete, so learning can be performed promptly. As the differential pressure command value is corrected by this learning value, scatter in the engagement completion timing on the next occasion when lock-up is performed can be suppressed.
[0075] The learning value is stored in relation to the differential pressure command value and the oil temperature of the transmission, so learning can be performed for each oil temperature. Hence, scatter in the engagement timing of the lock-up clutch can be definitively suppressed. It should be noted that the difference between the differential pressure command value and the real differential pressure depends on the oil temperature. As oil is supplied to the torque converter and transmission, the oil temperature of the transmission is a measure or guide of the oil temperature of the torque converter (temperature of the oil supplied to the lock-up clutch). The oil temperature affects the difference between the differential pressure command value and the real differential pressure. Specifically, the AT controller 1 searches the differential pressure deviation learning value LUprs_OFFSET (P_learn(Tai)) from the oil temperature Tatf, and adds the differential pressure deviation learning value LUprs_OFFSET to the slip command value LUprs_slp. In this way, on the next occasion smooth lock-up is performed, scatter in the engagement completion timing is suppressed by suppressing the effect of variation of the oil temperature Tatf and time-dependent variation of the lock-up clutch.
[0076] The learning value is stored by the memory for each oil temperature Tatf of the transmission 4 and for each the differential pressure command value P_ref, so learning can be performed for each oil temperature Tatf and for each the differential pressure command value P_ref.
[0077] The differential pressure deviation learning value P_learn(Tai) finally used in slip control is the value obtained by averaging the differential pressure learning values P_errorLO(Tai), P_errorMID(Tai), P_errorHI(Tai) relating to plural differential pressure command values for each oil temperature region. Thus, the error in the learning value P_error becomes small.
[0078] Further, by setting the learning prohibition conditions, learning is permitted only when smooth lock-up has been completed. Thus, the differential pressure deviation estimation value P_error can be calculated with higher precision based on the engine torque signal.
[0079] Although the invention has been described above by reference to a certain embodiment of the invention, the invention is not limited to the embodiment described above.
[0080] In the above embodiment, averaging was performed when the learning value of the whole temperature region of a certain row was stored. However, averaging may be performed when plural learning values have been stored in a certain row.
[0081] In the aforesaid embodiment, learning values are used when the lock-up clutch engages. However, learning values may be used when the lock-up clutch 6 smoothly releases. In other words, as shown in FIG. 8 , a learning value can be added to the slip command value LUprs_slp when the lock-up clutch 6 is released. In this way, the time from the start of release of the lock-up clutch to the completion of release of the lock-up clutch 6 can be made constant irrespective of change of the oil temperature Tatf.
[0082] In the aforesaid embodiment, to simplify the description, an example of ramp control was shown. However, ramp control of the corrected differential pressure command value LUprs may be performed with a slope a up to a predetermined time after determining that lock-up should be ON based on running conditions such as vehicle speed, and feedback control or feedforward control subsequently performed to achieve a target slip rotation speed calculated according to the running state.
[0083] In the aforesaid embodiment, the AT controller 1 received the engine torque Te from the engine controller 2 , but the AT controller 1 can receive the accelerator pedal stroke APO and engine rotation speed Ne (or pump impeller rotation speed Np) from the accelerator pedal stroke sensor 14 and engine rotation speed sensor 15 , and compute the engine torque Te from the accelerator pedal stroke APO and engine rotation speed Ne referring to a preset engine performance map.
[0084] Modifications and variations of the embodiments described above will occur to those skilled in the art, in light of the above teachings. The scope of the invention is defined with reference to the following claims.
[0085] The entire contents of Japanese Patent Application P2004-106506 (filed Mar. 31, 2004) are incorporated herein by reference.
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A lock-up clutch control device which controls a lock-up clutch provided in a torque converter installed between an engine and a transmission, is disclosed. The lock-up clutch control device changes over between a converter state and a lock-up state of the torque converter according to a differential pressure command value (LUprs) relating to a differential pressure supplied to the lock-up clutch. The lock-up clutch control device includes a differential pressure generating device ( 7,8 ) which generates the differential pressure supplied to the lock-up clutch; input torque detection means ( 2,14,15 ) which detects an input torque (Te) to the torque converter; and a controller ( 1 ). The controller ( 1 ) is programmed to compute a real differential pressure (P_lu) based on the detected input torque (Te) upon completion of the engagement of the lock-up clutch; compute a learning value (P_learn(Tai)) relating to a differential pressure deviation, based on the difference between the computed real differential pressure (P_lu) and differential pressure command value (P_ref) upon completion of the engagement of the lock-up clutch, and store the learning value (P_learn(Tai)); correct a present differential pressure command value (LUprs_slp) based on the learning value (P_learn(Tai)); and send the corrected differential pressure command value (LUprs) to the differential pressure generating device ( 7, 8 ).
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FIELD OF THE INVENTION
The present invention is directed to a handling apparatus employed to handle panel like articles, such as the main body panel components, which are to be subsequently assembled as a unitized vehicle body, to successively advance the panels to each of a series of work stations on a production line basis, and more particularly to the overhead transfer clamp actuator mechanism and linkage for releasibly engaging the panels during advancement of the articles between work stations.
BACKGROUND OF THE INVENTION
In the assembly of a unitized body, the first step in the assembly or framing of the body brings together at the first framing station on the body assembly production line various major panels, locates the panels in assembled relationship with each other and, while the panels are so located, welders weld the panels to each other to form a vehicle body shell. Typically, this first step in the framing process will involve a vehicle body floor panel, right and left hand body side panels, a fire wall panel and a roof panel or roof header members extending transversely between the upper portions of the body side panels. Once the panels are assembled to each other at the first framing station, access to portions of the individual panels at the interior of the body shell becomes restricted, and it is thus conventional practice to perform several preassembly steps on the individual panels before they are advanced to the framing station. In the case of a body side panel, for example, the panel is initially stamped from sheet metal, and is then advanced through a series of work stations where additional parts, such as door latch and hinge reinforcements, mounting brackets, stiffeners, etc., are welded in place on the sheet metal stamping.
In a commonly owned U.S. Pat. No. 4,991,707 issued on Feb. 12, 1991 there is disclosed a conveyor for conveying a panel to a series of work stations where the preframing operations referred to above are performed on the panel. The conveying system includes a carrier mounted for movement along an elevated horizontal path extending past a series of work stations. A generally rectangular open support frame is mounted along one edge on the carrier for pivotal movement relative to the carrier about a horizontal axis parallel to the conveying path. While the carrier is being advanced from one work station to the next, the support frame is maintained in a horizontal elevated position well clear of the plant floor. The panel, during this transfer step, is held against the underside of the support frame by what will be referred to generally as a plurality of clamps. On arrival at a work station, the carrier is stopped and a manipulator associated with the conveyor pivots the support frame downwardly to a vertically inclined or vertical position relative to the carrier to locate the panel in adjacent relationship with a stationary panel receiving work frame at the work station. The panel is transferred to the stationary work frame and the support frame is then pivoted back upwardly to its horizontal position clear of the panel on the work frame. After the work operations have been performed on the panel while the panel is held on the stationary work frame, the support frame is again pivoted downwardly, the panel is reclamped to the support frame, and the support frame with the panel is then pivoted back upwardly to its horizontal position relative to the carrier for advancement to the next work station.
In the panel conveying system described above, the irregular shape of the panel requires that several individual releasable clamps be located on the support frame to positively retain the panel on the frame during transit from one stationary panel receiving frame to the next. To facilitate transfer of the panel back and forth between the support frame and stationary work frame, it is essential that all of the several clamps be simultaneously released or engaged. The length of the conveying path and the requirement of pivotal movement of the support frame relative to its carrier makes it impractical to connect pneumatic or hydraulic supply lines or electrical cables to the individual support frames to pneumatically or electrically actuate the clamping devices. The clamps, and the clamp actuating devices must thus be so designed that the clamps are positively retained in their clamping position during transfer movement of the support frame and positively retained in their unclamped configuration while the support frame is separated from the panel at the work station.
In a commonly owned U.S. Pat. No. 5,141,093 issued Aug. 25, 1992, there is disclosed a conveyor for conveying a body side panel to a series of work stations where the clamp actuator is located at a common location on the stationary work frame of each work station and operatively engages associated coupling members on the moveable panel support frame when in the lowered position of each respective work station. It is difficult to provide a common location for the clamp actuator position at all work stations, since the desired location may interfere with preframing operations at one work station while being acceptable at all other work stations. In addition, the proper alignment of the moveable support frame coupling members with the stationary work frame clamp actuator is difficult to obtain initially, and difficult to maintain over time. The system requires precise positioning of the carrier along the elevated horizontal path with respect to the stationary work frame of each work station, and precise positioning of the support frame as it pivots from the elevated transport position to the lowered panel transfer position for proper operable engagement with the clamp actuator on the stationary work frame of each work station. Therefore, it would be desirable to provide an overhead clamp actuator and linkage apparatus that overcomes these disadvantages.
SUMMARY OF THE INVENTION
The present invention is especially directed to a clamping system in which a plurality of individual clamping or positioning devices carried on the support frame may be simultaneously shifted between their respective panel clamping or retaining positions and respective released or retracted positions and in which the clamps or locators are positively retained in either of their actuated or released positions.
In accordance with the present invention, a support frame adapted to be mounted along one edge on the carrier of a conveyor as described above is formed as an open frame of a configuration determined by the shape of the side panel which is to be handled by the frame. For purposes of description, the support frame may be considered as a generally flat rectangular frame whose outer dimensions approximate the length and height of the side panel to be handled so that the side panel can be mounted in a stable position on one side of the frame. To locate and retain a side panel on the frame, a number of locating and panel retaining devices or clamps are mounted at various locations on the frame chosen so that they will cooperatively retain a side panel in a fixed preselected position relative to the frame.
Two types of locating devices may be employed. The first type of locating device can simply be a pad or pin fixedly mounted on the support frame to engage the outer side surface of the body panel which, when it is retained on the support frame, faces the support frame. A second type of locating device can take the form of a pad which is movable between a first position in which it engages an edge surface of the body side panel and a retracted position in which the locating pad is retracted clear of the body panel to accommodate loading or unloading of the panel to or from the support frame.
A number of panel retaining or clamping devices are also mounted at appropriate locations on the support frame. Typically the clamping or retaining device will include a generally L-shaped panel engaging member pivotally mounted on the support frame for movement between a retaining position in which the retaining member projects inwardly beyond an edge of the panel to engage the inner side of the panel to lightly clamp the panel against the stationary locating pads described above.
An actuating shaft is mounted on the support frame for rotary oscillation about a shaft axis which is fixed relative to the support frame. An actuating crank is rotatively fixed at one end to the shaft and operably connected to a coupling member for actuation by the drive device when in the lowered position at the work station. Other crank arms rotatively fixed to the shaft are individually coupled by links to the respective clamping or retaining members in a manner such that when the actuating shaft is at one end limit of rotary oscillation, all clamps are in their panel retaining position, and when the actuating shaft is at its opposite end limit of movement, all clamps are located in their panel releasing or retracted positions. A lock device is provided operably mounted on the carrier end plate and the coupling member to positively lock the actuating shaft at either of its end limits of rotary oscillation to thereby positively retain the clamps in either of their panel retaining or panel release positions when the support frame is in the raised or transport position.
Each work station is provided with a power driven clamp actuating device and a lock releasing device. The lock releasing device at the work station is accomplished by a stationary abutment surface or cam member having cam surfaces formed thereon located on the carrier. The cam surfaces are located to engage and retain a cam follower with first or second cam surfaces corresponding to clamp released and engaged positions. The cam surfaces only release the cam follower carried with respect to the support frame when the support frame approaches its end limit of downward pivotal movement toward the stationary panel receiving work frame at the work station. The clamp actuating device includes a drive member mounted on the fixed frame for reciprocation along a fixed path at the work station and having an downwardly opening U-shaped recess which will receive a roller mounted on a coupling member connected to the actuating crank on the support frame, when the support frame is at its downward end limit of movement toward the panel receiving work frame at the work station. A power driven actuating device is operable to position the drive member at either of two end limits of linear reciprocation which correspond to the opposite end limits of rotary oscillation of the coupling member and crank actuating arm connected to the actuating shaft on the support frame. The drive member and coupling member are located in a corresponding positions, with both members either in the clamped position or the unclamped position.
As the support frame pivots downwardly on the conveyor to its end limit of movement toward the stationary panel receiving work frame, the roller of the coupling member enters the U-shaped recess in the drive member. The power driven actuating device is then actuated to shift the drive member to its opposite end limit of movement and in so doing, the engagement of the drive member with the roller of the coupling member rotates the actuating shaft to the opposite position, either the engaged or released position. For example as described above, after the side panel has been transferred from the support frame to the panel receiving work frame and the actuating shaft rotated to the clamp released position, the support frame is pivoted upwardly on the conveyor to its horizontal or raised position. When not transporting a panel between work stations, the support frame would normally be positioned in the raised position with all clamps released. After the work operation has been performed on the body panel, the support frame is pivoted downwardly again and, as it approaches its end limit of pivotal movement toward the panel receiving work frame, the roller again enters the U-shaped recess in the drive member. After the body panel has been positioned on the support frame, the drive member is driven back to its other end limit of linear reciprocation, and this movement of the drive member through drives the coupling member to rotate the actuating shaft on the support frame to reset the clamps to the engaged or clamping position to hold the panel with respect to the support frame while being moved to the raised position and transported to the next work station. The various locating pads on the support frame may likewise be actuated and released by operation of the actuating shaft.
Other objects, advantages and applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:
FIG. 1 is a simplified perspective view with various parts omitted of a conveying system and work station to which the present invention is applicable;
FIG. 2 is a simplified end view showing a portion of the conveying system shown in FIG. 1 and a somewhat modified form of work station;
FIG. 3 is a top plan view of a support frame embodying the present invention with certain parts omitted for the sake of clarity;
FIG. 4 is an end view of the support frame of FIG. 1, again with certain parts omitted;
FIG. 5 is a simplified end view showing a portion of the conveying system shown in FIG. 1 with a mounting member in a lowered position and a clamp actuator in a clamped position;
FIG. 6 is a simplified end view showing a portion of the conveying system shown in FIG. 1 with a mounting member in a lowered position and a clamp actuator in a retracted position;
FIG. 7 is a simplified end view showing a portion of the conveying system shown in FIG. 1 with the mounting member in a raised position and the clamp actuator locked in a clamping position;
FIG. 8 is a partial cross-sectional view taken as shown in FIG. 5 showing details of a clamp actuator drive member, a clamp actuator coupling member and cam member;
FIG. 9 is a simplified end view showing a portion of the conveying system shown in FIG. 1 with the mounting member in a raised position and the clamp actuator locked in a released position;
FIG. 10 is a partial cross-sectional view taken as shown in FIG. 5 showing details of a portion of the clamp actuator drive assembly; and
FIG. 11 is a partial cross-sectional view taken as shown in FIG. 5 showing details of a mounting for the clamp actuator drive assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIGS. 1 and 2, a conveying system of the type which employs the present invention is disclosed in simplified form with many structural details omitted. A conveying system of the type shown in FIGS. 1 and 2 is disclosed and described in detail in commonly owned U.S. Pat. No. 4,991,707 issued on Feb. 12, 1991 and U.S. Pat. No. 5,141,093 issued Aug. 25, 1992, which are incorporated herein by reference and to which reference may be had for further details of the system in general.
The conveyor system of the present invention includes a pair of horizontally extending rails 10 and 12 which are fixedly mounted on the fixed frame F of the conveyor. A carrier designated generally 16 includes a pair of end plates 18, 20 which are fixedly secured to each other by a horizontally extending rigid shaft 22 on which is rotatably supported a sleeve 24. The carrier 16 may include additional frame members secured to and extending between end plates 18 and 20, however, such additional members have been omitted from the drawings in order to provide a clearer view of other parts of the assembly. The two end plates 18, 20 are supported on rails 10 and 12 as by rollers 26. Carrier 16 is driven in movement along rails 10 and 12 by suitable drive means, not shown, which is operable to stop the carrier when the carrier is in operative alignment with work stations, such as the work station W. Typically, several work stations will be located at uniformly spaced locations along the conveying path defined by rails 10 and 12, and the carriers 16 will be driven in intermittent movement along rails 10 and 12 in incremental steps from one work station to the next.
A panel support frame designated generally 28 is fixedly mounted on the sleeve 24 as by mounting members 30, 32. The central mounting member 30 carries a plurality of rollers 34 which ride against a vertical side surface 36 of the lower rail 12. The engagement between rollers 34 and the side surface 36 of rail 12 normally maintains the support frame 28 in the generally horizontal position shown in FIG. 1.
Upper rail 10 is formed as a continuous fixed rail entirely fixedly supported from the fixed frame F. Lower rail 12 is formed with a relatively short moveable rail section 38 at each work station which normally is disposed in alignment with the fixedly mounted portions of lower rail 12. Rather than being mounted fixedly on the fixed frame F, as are the remaining major portions of lower rail 12, moveable rail section 38 is mounted, as best seen in FIG. 2, on a manipulator frame 40 which is supported as by rollers 42 mounted on each side of frame 40 which are received in curved roller tracks 44 mounted on frame plates 46 fixedly secured to fixed frame F. The curvature of roller tracks 44 follows a constant radius curve centered on the axis of sleeve 24. A drive motor, such as a hydraulic cylinder 48 coupled to frame F and a piston rod 50 coupled to manipulator frame 40, is employed to drive the manipulator frame in movement guided by roller tracks 44 from the normal position shown in full line in FIG. 2 in which the movable rail section 38 carried by manipulator frame 40 is in alignment with lower rail 12 and an actuated position in which frame 40 is shifted to the position shown in broken line in FIG. 2. When the manipulator frame 40 is in the full line position shown in FIG. 2, the support frame 28 is in the full line position of FIG. 2 with frame 28 lying in a horizontal general plane. When the piston rod 50 of the manipulator frame motor is retracted, the moveable rail section 38 moves from the full line position in clockwise movement about the axis of shaft 22, with sleeve 24 rotating relative to shaft 22. The weight of the horizontally projecting support frame maintains the rollers 34 on the mounting member 32 in contact with the side surface 36 of rail section 38 so that the support frame 28 pivots downwardly from the full line position shown in FIG. 2 to the broken line position indicated.
Support frame 28 is provided with a number of locator and retaining members (not shown in FIG. 1) which are operable to releasably retain and locate a body panel P on the underside of frame 28 when the frame is in its normal horizontal position shown in full line in FIG. 2. The number and locations of the locating and retaining members is entirely dependent on the configuration of the particular panel P being handled. In FIG. 2, two locator members 52 are indicated in broken line as are two retainer members 54. The number and locations of locator members 52 and retaining members 54 as shown in FIG. 2, is intended simply to indicate the general manner in which panel P is retained on support frame 28--in actual practice additional locator and retainer members will be employed. As most clearly shown in FIG. 2, a panel receiving work frame 56 is fixedly mounted at work station W in a position and orientation to receive a panel P from support frame 28 when the frame 28 is in the broken line position indicated in FIG. 2. The panel receiving work frame 56 will be provided with suitably located pads and locating members such as 58, 60 to support the panel on the stationary receiving work frame in a fixedly located position with respect to assembly tooling, such as the robotic welder R illustrated in FIG. 1. The panel receiving work frame 56 may also be provided, where appropriate, with releasable clamps, not shown.
Mounted on the fixed frame F at work station W is a clamp actuator assembly designated generally 64 best seen in FIGS. 5-11, which will be described in greater detail below. Clamp actuator assembly 64 functions to release the various releasable retainer members 54 or clamps which are mounted on support frame 28 when the frame arrives at the broken line transfer position shown in FIG. 2.
As previously stated, FIGS. 1 and 2 are extremely simplified drawings intended simply to illustrate how the panel carrying support frame 28 is conveyed and manipulated. Thus, many structural details have been omitted from these two figures in that the scale of these figures, particularly FIG. 1, is too small to clearly illustrate details of the retaining and latch actuating mechanisms to which the present invention is directed and further because the configuration of support frame 28 and the location of the various locator and retaining devices on the support frame will vary in accordance with the configuration of the specific panel being handled by the apparatus. Details of the locating and clamp actuating devices to which the present invention is directed are best seen in FIGS. 3-11.
Referring first to FIG. 3, a typical support frame designated generally 28A corresponding to the simplified frame 28 of FIGS. 1 and 2 is shown in top plan view as including an open frame work made up of rigidly interconnected longitudinally and transversely extending frame members such as 72, 74, 76, 80, 82, etc. The overall shape of the frame as viewed in plan depends to a large extent on the overall shape of the panel P which is to be handled by the frame. Support frame 28A includes fixedly mounted mounting plates 84, 86 and 88 adapted to be fixedly mounted on the support members such as 30, 32 of a carrier 16 referred to above in the description of FIGS. 1 and 2.
A number of fixedly mounted locator pads, two of which are indicated in FIG. 3 at 90 and 92 are fixedly mounted at selected locations on frame 28A to function in the manner of locator pads 52 as shown in FIG. 2--that is to engage the outer side surface of the panel P which is located below frame 28A as viewed in FIG. 3. It will be appreciated that while only two stationary pads 90, 92 are illustrated, additional pads will be employed, where necessary.
A plurality of pivoted retainer or clamp assemblies designated generally 94, 96, 98 and 100 are mounted on frame 28A to function in a manner similar to the retainer members 54 of FIG. 2. Again, the number and locations of retainer or clamp assemblies such as 94, 96 and their specific location on the support frame is determined by the configuration of the panel P being handled. In addition to the pivoted retainer or clamp members 94, 96, 98 and 100, one or more retractable locator members, one of which is indicated generally at 102 in FIG. 3 may be mounted on frame 28A. The fixed locating pads 90, 92, the pivotable retainer or clamp assemblies such as 94, 96, etc., and the retractable locator members such as 102 all project downwardly from the lower side of frame 28A as viewed in FIG. 3 to locate the panel P in spaced relationship below the bottom side of frame 28A.
Mounted on the upper side of frame 28A is a transversely extending shaft 104 supported on frame 28A for rotation about its axis as by pillow block 106 mounted on frame 28A.
As best seen in FIG. 4, a plurality of crank arms such as 110, 120 are rotatably fixed to shaft 104 to project upwardly or downwardly generally from the shaft. These crank arms are coupled by links to the various clamping or retainer assemblies 94, 96, 98 and 100, a link 112, for example, being pivotally connected at one end to the crank 110 and pivotally connected at its opposite end to a clamp retainer member 114 which is pivotally mounted as at 116 on a mounting bracket 118 fixed to frame 28A. Another link 108 similarly extends from a crank 120 on shaft 104 to a pivotally mounted member of clamp assembly 100, while another link 122 extends from still another crank 124 on shaft 104 to the clamp assembly 98. The clamp assembly 96 of FIG. 3 is not shown in the side view of FIG. 4 for purposes of clarity.
Referring to FIG. 4, it is seen that if shaft 104 is rotated in a counterclockwise direction, this rotation of the shaft will cause crank 110 to draw link 12 to the right as viewed in FIG. 4, thus driving the pivoted clamp member 114 in clockwise movement about its pivot 116 to thereby withdraw the lower end of clamp 114 clear of the edge of the panel P. Similarly, those cranks, such as 120, on shaft 104 which project upwardly from the shaft will draw their respective links 122, 108, to the left as viewed in FIG. 4 to release the various clamps or retainer members coupled to the links. A subsequent actuation of crank 126 and shaft 104 to the original positions illustrated in FIG. 4 will relocate the various clamps and retaining members in their clamping or retaining positions.
In addition to the various clamp actuating cranks described above, a shaft actuating crank 126 is fixedly secured to shaft 104 and is connected through various links 200 (best seen in FIGS. 3, 5 and 6) and link 202 (best seen in FIGS. 5 and 6) to connect to the coupling member 204. Referring now to FIGS. 5-8, the coupling member 204 can be driven in response to actuation of the cylinder 172 about pivot 166 between first and second end limits of travel corresponding to the clamped position and released position of the shaft 104. As illustrated in FIG. 5, the mounting member 30 is in the lowered position to position support frame 28 in close proximity to the work frame, such as 56 illustrated in FIG. 2. In this position, the cam follower roller 148 is disengaged from the cam member 142 so that the pneumatic cylinder 172 can be actuated to drive the drive member 164 between its first and second end limits of travel. In this position, the roller 128 (best seen in FIG. 8) is engaged within the recess 168 (best seen in FIG. 7 or 9) of the drive member 164. When in the clamped position as illustrated in FIG. 5, the manipulator, such as hydraulic cylinder 48 (seen in FIG. 2) can be actuated to move the mounting member 30 from the lowered position to the raised position as illustrated in FIG. 7. In the position as illustrated in FIG. 7, the roller 128 is disengaged from the U-shaped recess 168 of the drive member 164, while the cam follower roller 148 is engaged with the cam surface 144 of the cam member 142 to lock the locator members and retainer members in the clamped position. The pivot 166 is supported from the sleeve 24 by radially extending arm 206, so that the coupling member 204 and associated roller 128 and cam follower roller 148 move in conjunction with rotation of the sleeve 24 about the shaft 22, which also corresponds to movement of the mounting member 30 supported from the sleeve 24 and frame 28 supported from mounting member 30.
After movement of the carriage 16 between workstations, the manipulator, such as hydraulic cylinder 48, is actuated to rotate the frame 28 and associated mounting members 30, 32 and sleeve 24 about shaft 22 to move from the elevated position to the transfer position, such as that illustrated in FIG. 2. The movement causing the coupling member 204 to move from the position illustrated in FIG. 7 to a position corresponding to that illustrated in FIG. 5. When in the position of FIG. 5, the pneumatic cylinder 172 is actuated to move the drive member 164 from the extended position to the retracted position as illustrated in FIG. 6 to correspondingly move the locator member and retainer members from the clamped position to the released position to deposit the panel being transported by the carrier 16 between workstations to the work frame 56 as illustrated in FIG. 2. The manipulator, such as hydraulic cylinder 48 is then actuated to move the frame 28 and associated mounting member 30, sleeve 24, arm 206 and coupling member 204 about the shaft 22 to the raised position as illustrated in FIG. 9. In this position as illustrated in FIG. 9, the roller 128 is disengaged from the U-shaped recess 168 of the drive member 164 and the cam follower roller 148 is engaged with the cam surface 146 of the cam member 142 to lock the locator members and retainer members in the released position. When the preframing operations have been performed on the panel at the work frame 56 of the workstation are completed, the manipulator, such as hydraulic cylinder 48, is actuated again to move the frame 28 from the elevated position as illustrated in FIG. 9 to the transfer position illustrated in FIG. 6. In the position illustrated in FIG. 6, the roller 128 is again engaged within the U-shaped recess 168 of the drive member 164 allowing the pneumatic cylinder 172 to be actuated from the retracted position (shown in FIG. 6) to the extended position (shown in FIG. 5) to drive the coupling member 204 about the pivot 166, which correspondingly moves the locator members and retainer members to the clamping position on the support frame 28. When in the clamping position, the manipulator, such as hydraulic cylinder 48, can again be actuated to move the frame 28 from the transfer position (shown in FIG. 5) to the elevated position (shown in FIG. 7). The support frame 28 must be at its lower end limit of movement relative to the carrier 16 of the conveyor before rotation of the shaft 104 can be accomplished, and therefore only when the panel support frame 28 is closely adjacent the panel receiving work frame 56 at the work station is it possible to move the locator members and retainer members between the clamping and release positions.
Referring now to FIGS. 10 and 11, details of the clamp actuator drive member 164 and pneumatic cylinder 172 mounting to the fixed frame F are illustrated. The coupling member assembly 204 and cam member 142 are carried by the carrier 16 and move from workstation to workstation as the carrier moves along the fixed frame F. A clamp actuator drive assembly 64 is mounted at each of the workstations to the fixed frame F for operative engagement with the roller 128 when the frame 28 is moved to the lowered or transfer position by the manipulator, such as hydraulic cylinder 48 shown in FIG. 2.
Details of clamp actuator 64 are best seen in FIGS. 5-11. The actuator includes a frame 162 located on the fixed frame F at each work station. A drive member 164 is mounted for reciprocal movement on frame 162. Drive member 164 is formed at one end with a downwardly opening U-shaped recess 168 whose width is somewhat greater than the diameter of the roller 128 on the coupling member 204 connected to the crank arm 126 of shaft 104 through links 200 and 202. The piston rod of a pneumatic cylinder 172 is coupled to drive member 164. Pneumatic cylinder 172 is mounted on fixed frame 162 with a spring biased support 208 allowing movement along a slot 210 formed in fixed frame 162 if required in response to excessive contact of the roller 128 of the coupling member 204 with respect to the drive member 164. The drive member 164 is shown in FIGS. 6 and 9 with its piston rod in a retracted position. At this time, a stop pad (not shown) fixedly mounted on coupling member 204 is engaged with a fixed stop mounted on carrier 16 to establish an end limit of movement of the coupling member 204 in a counterclockwise direction. On actuation of pneumatic cylinder 172 to extend its piston rod, coupling member 204 will be driven in clockwise movement about pivot 166 until a second stop pad (not shown) mounted on the coupling member 204 engages a fixed stop abutment on carrier 16. Cylinder 172 is connected in a conventional manner to a reversing valve to drive in either direction in accordance with the position of the valve. Control circuitry for controlling actuation of the cylinder 172 functions in a well known manner to maintain the piston rod at one end of its stroke until the circuit is actuated, at which time the piston rod is driven to the opposite end of its stroke and there maintained until the next subsequent actuation. Drive member 164 is thus normally located at one or the other of its end limit of movement.
In FIGS. 5 and 7, drive member 164 is shown at that end limit corresponding to a clamp closed position of crank 126. With drive member 164 in the position shown in FIG. 5 and crank 126 of shaft 104 in the position indicated, roller 128 on the coupling member 204 will be located within recess 168 of the drive member 164 when support frame 28A arrives at the lowered transfer position as illustrated in FIG. 5. With the cam follower 148 free of the corresponding cam surface 144 of cam member 142, cylinder 172 may now be actuated to retract its piston rod inwardly as viewed in FIG. 5 to the position illustrated in FIG. 6, thus causing the coupling member 204 to rotate counterclockwise about pivot 166 and in so doing to drive crank arm 126, and thus shaft 104 in counterclockwise rotation about the axis of shaft 104. The support frame 28 can then be moved from the transfer position of FIG. 6 to the raised position of FIG. 9 causing the cam follower 148 to lock the locator and retainer members in position.
OPERATION
The conveying path defined by conveyor rails 10 and 12 typically will extend past several work stations uniformly spaced along the conveyor path. At each work station, the conveyor will be provided with a manipulator assembly operable to pivot the support frame 28 or 28A from the generally horizontal conveying position shown in FIG. 1 to and from a lowered position where the support frame is closely adjacent a panel receiving frame such as 56 (FIG. 2) at the work station. Depending on the work operation to be performed, the panel receiving frame may be located in an inclined position such as that of the receiving frame 56 shown in FIG. 2 or the receiving frame may be located in a vertical position. Each work station will include a clamp actuator such as 64, a lock release device 154.
The first station at the upstream end of the conveyor line is a loading station at which the panel P is loaded on its support frame 28 or 28A. To accomplish this loading, the manipulator at the loading station is actuated to lower the support frame to its lowered position at which the movable locating devices are located in their disengaged position. If the various clamping devices, such as 98, on the frame are in their clamping position, clamp actuator 64 is actuated to release the clamps.
The panel P is then positioned on the frame 28A with the side surface of the panel facing frame 28A engaging all of the various fixedly mounted pads on the support frame 28 or 28A. Clamp actuator 64 is then actuated as described above, to swing the various clamping assemblies into the clamping position.
The manipulator is then actuated to swing the support frame, with the clamped panel, upwardly from the loading position to the transport position illustrated in FIG. 1. The support frame is then advanced along conveyor rails 10 and 12 to the first work station. On the arrival of the support frame at the first work station, the manipulator at that station pivots the support frame downwardly toward the panel receiving frame, (such as frame 56 of FIG. 2). The cam follower roller 148 on the coupling member 204 moves free from the cam surfaces 144 and 146 of the cam member 142 only when the support frame 28 reaches the transfer or lowered position, allowing the drive member 164 to be actuated with the roller 128 engaged within the U-shaped recess 168 to drive the actuating shaft crank 126 rotatably with respect to the shaft 104. The actuating device 64 is then actuated to drive its drive member 164 in the clamp opening direction, this movement of drive member 164 drives crank 126 through the coupling member 204 to rotate the actuating shaft 104. As described above, actuating shaft 104 is coupled by cranks on the shaft and links to the various clamping devices, such as 98, to pivot the various clamping devices to withdraw the panel supporting elements from beneath the panel P. Support of the panel P is then transferred to the panel receiving work frame 56 at the work station. The support frame 28 or 28A is then driven by the manipulator device, such as hydraulic cylinder 48, at the work station back to its elevated horizontal position to fully expose the panel P supported on receiving work frame 56 to tooling located at the work station.
After the work operation on the panel has been completed, the tooling is withdrawn from the panel and the support frame 28 or 28A is again driven by the manipulator back to its lowered position. The panel is then transferred from the receiving work frame 56 back into engagement with the various fixed pads as in the original loading operation, the clamp actuator 64 is actuated to restore the various panel retaining clamping devices, such as 98, to their panel clamping position, and the manipulator is then actuated to swing the panel upwardly away from the receiving work frame back to the substantially horizontal conveying or transport position. This process is then repeated at succeeding work stations with the panel being finally unloaded from the support frame 28 or 28A at the final work station.
As described above, the actuating shaft 104 and thus all of the pivotal clamps are positively retained in the position to which they have been last driven by a clamp actuator 64 by the engagement of the cam follower roller 148 (FIGS. 5-9) on either of cam surface side 144, 146 of the cam member 142. The only time cam follower roller 148 is disengaged from the cam surfaces of the cam member 142 is when the support frame 28A is at a closely adjacent fully lowered position. From the foregoing description of an operating cycle, it is believed apparent that all of the various shaft actuated clamps, such as clamp 98, are locked in either their clamping position or unclamping position at all times except when support frame 28 or 28A is either at or closely adjacent a fully lowered position at a work station or the panel P is supported by the panel receiving frame at a work station.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.
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An apparatus for conveying panels, such as vehicle body side panels to and from work stations located at spaced locations along a conveyor includes a panel support frame mounted on the conveyor for movement along the conveying path with the support frame in an elevated generally horizontal conveying position. The support frame carries a plurality of mechanically actuable releasable clamps adapted to retain a panel engaged against a group of locator pads fixedly mounted on one side of the support frame. A second group of locator pads movably mounted on the frame are normally biased into engagement with the panel at spaced locations around its periphery to hold the panel in a predetermined position laterally of the support frame. The support frame mounts an actuator member coupled to all of the clamps to position all clamps in a panel clamping position when the actuator member is in a first position and to position all clamps in a panel release position when the actuator is in a second position. A coupling member on the support frame normally locks the actuator member against movement from either of its positions. The conveyor includes a manipulator operable when the support frame is at a work station to pivot the support frame downwardly from its conveying position to a downwardly inclined transfer position. Actuating devices located on the fixed frame at the work station are operable when the support frame is in its transfer position to release the coupling member, disengage the movable locator pads and shift the clamp actuator member between its first and second positions.
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TECHNICAL FIELD
This invention relates to a control circuit for selectively varying the displacement of a pump, the circuit including primary control means and override control means for overriding the primary control means independent of actuation thereof.
BACKGROUND ART
Variable displacement pumps, such as those employed in hydrostatic transmissions, are adapted to have the displacements thereof varied between minimum and maximum levels upon adjustment of servo-systems connected to the pumps which are adapted to actuate swash plates of the pumps in a conventional manner. U.S. Pat. No. 3,996,743, assigned to the assignee of this application and issued to Cyril W. Habiger on Dec. 14, 1976, discloses a conventional control circuit for controlling the displacement of pumps of this type.
The control circuit comprises an underspeed actuator which is connected to the servo-systems and further connected to a venturi to receive a differential fluid pressure signal therefrom which is proportional to the speed of a vehicle's engine to automatically control the underspeed actuator for automatically varying the displacement of the pumps under certain conditions of engine operation. The control circuit further comprises a directional control valve movable to a vent and override position to equalize the differential fluid pressure signal whereby the automatic operation of the underspeed actuator may be overriden.
When the control valve is in this position, pressurized fluid is blocked from communicating with replenishing and relief valves of the pump system and also to normally "on" brakes of the vehicle which must be released by fluid pressure. When the control valve is moved from its vent towards its maximum speed position, pressurized fluid is communicated to the brakes to release them and also to the replenishing and relief valves of the pump system to condition the pumps for operation. Simultaneously therewith, the above-mentioned differential fluid pressure signal is re-established to permit the underspeed actuator to control displacement of the pumps automatically, should the need arise.
It has proven desirable, particularly in the application of the control circuit of the present invention to hydrostatic transmissions, to construct and arrange an override control valve as a separate unit from a main control valve which controls the venting and primary control functions of the circuit. In addition to rendering the circuit efficient for expeditious and close control by the operator, the respective control valves and associated components of the control circuit may be arranged for efficient servicing. Also, the main control valve can be maintained operational in its "run" position upon movement of the override control valve from its closed position to its open, override position and back to its closed position.
DISCLOSURE OF INVENTION
The present invention is directed to overcoming one or more of the problems as set forth above.
In one aspect of the invention, the control circuit comprises a source of pressurized fluid, a variable displacement pump means for having the displacement thereof varied in response to communication of pressurized fluid thereto, primary control means connecting the source with the pump means for selectively venting pressurized fluid from the pump means or for varying the displacement of the pump means between minimum and maximum values, and override control means for overriding the same when the primary control means is in its actuated condition of operation for selectively varying the displacement of the pump means, independent of actuation of the primary control means.
In another aspect of this invention, the override control means preferably comprises a rotatable valve spool for closely controlling a fluid pressure signal normally utilized to automatically control the displacement of the pump means. In addition to providing close control of the override function, the valve is adapted to provide a much more compact package in comparison with valves adapted for linear movement.
In still another aspect of this invention, the primary control means includes a pair of associated first and second valve means which form a fluid-actuated reset means for assuring that the variable displacement pump means will not be initially actuated with the control circuit maintained in a "run" condition of operation.
The control circuit of this invention thus separates the above primary control and override functions to render the systems highly efficient for operator operation and adapts it for expeditious servicing.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 schematically illustrates a control circuit embodiment of the present invention with portions thereof broken-away for clarification purposes;
FIG. 2 is a sectional view illustrating an override control valve associated with a reset valve and venturi employed in the control circuit;
FIGS. 3 and 4 are sectional views illustrating the reset valve in progressively actuated conditions of operation; and
FIGS. 5-7 are enlarged sectional views taken through the override valve, in the direction of arrows V--V, VI--VI, and VII--VII, respectively, in FIG. 2.
BEST MODE OF CARRYING OUT THE INVENTION
General Description
FIG. 1 illustrates a control circuit embodiment of this invention comprising a source of pressurized fluid 10, preferably comprising an engine-driven positive displacement pump 11 adapted to charge an inlet line 12 of the circuit with pressurized fluid (hydraulic) from a common reservoir or tank 13. As described more fully hereinafter, a primary control means includes a control lever 14 adapted to be moved in a V-shaped slot 15 by an operator to move a three-position directional control valve 16 in a "vent", "reset" or "run" position of operation for selectively controlling the operation and displacement of an engine-driven variable displacement pump P of a pump means 17. In the illustrated embodiment, the pump means (further comprising hereinafter described servo system 26 and a replenishing valve 43) is suitably connected to a fluid motor M of a hydrostatic transmission 18. The transmission package further includes a closed loop 19 interconnected between pump P and motor M in a conventional manner, as more fully described in above-referenced U.S. Pat. No. 3,996,743.
In general, when directional control valve 16 is moved to its "run" position by control lever 14 (either forward or reverse) by means of a schematically illustrated linkage 20, normally "on" brakes 21 of a vehicle will be released and the control circuit will be conditioned to supply pressurized fluid to pump means 17 from engine-driven pump 11. As further described in the above-referenced patent, speed control lever 14 is further mechanically connected, as schematically illustrated at 22, to a standard underspeed actuator or control means 23 to manually adjust the position of the illustrated piston 23' thereof. The selected position of piston 23' will, in turn, determine the displacement of pump P, via a linkage 24 interconnected between a servo system 26 and underspeed actuator 23, between minimum ("full underspeed") and maximum ("zero underspeed") values. The position of piston 23' of the underspeed actuator and thus the displacement of pump P is further responsive to a fluid pressure differential or signal created across a venturi 25 and communicated to either end of piston 23', such pressure differential being proportional to the speed of pump 11 and the engine.
Should the operator desire to override the above, briefly described fluid pressure signal he need only to depress a pedal 27 of an override and control means which comprises a rotary override valve 28. In essence, rotary movement of override valve 28 to an open position will function to vary the fluid pressure signal in a closely controlled manner to selectively reposition piston 23' in underspeed actuator 23 whereby the displacement of pump P can be changed for certain operating conditions of the vehicle. Return of the override valve to its normally closed position will not affect the prior setting of speed control lever 14 and associated directional control valve 16 and permits the underspeed actuator to reassume normal operation.
DETAILED DESCRIPTION
Communication of pressurized fluid to an inlet 29 of venturi 25 from pump 11 will create a pressure differential or signal between a line 30 connected to inlet 29 and a line 31 connected to the throat portion of the venturi. This differential pressure will be communicated to either end of piston 23' of underspeed actuator 23, via lines 32 and 33, the latter line being connected to line 30 through a quick response or shunt valve 34. The underspeed actuator will function in a conventional manner during normal operation to regulate servo system 26 of pump means 17 for controlling the displacement of pump P. Shunt valve 34 essentially functions to interconnect lines 30 and 33 for fluid flow therebetween and is adapted to open to communicate line 33 with lines 31 and 32 when piston 23' of underspeed actuator 23 moves downwardly quickly to create a pressure surge in line 33. Shunt valve 34, although desirable, could be eliminated from the control circuit which would remain fully operational.
A pressure regulating valve 35 is connected in a line 36, connected to a downstream side of venturi 25, to supply pressurized fluid at a predetermined level to hydrostatic transmission 18, via a line 37. A line 38 is interconnected between line 36 and servo system 26 to comunicate pressurized fluid at a predetermined level to the servo system in a conventional manner.
If so desired, a bypass arrangement, comprising a line 39 and an adjustable orifice 40 connected therein, may be interconnected between lines 30 and 37. This bypass arrangement across venturi 25 may be utilized to closely control and finely "tune" the differential pressure drop across the venturi and the fluid pressure signal communicated to underspeed actuator 23 to compensate for manufacturing variances and the like in the venturi, pumps, etc. This bypass arrangement, although desirable, could be eliminated from the control circuit which would remain fully operational.
A pressure relief valve 42 is connected in line 37 to assure that a replenishing valve 43 of pump means 17 is conventionally charged with a predetermined level of pressurized fluid. In addition to supplying fluid pressure to the hydrostatic loop 19 of transmission 18, valve 43 further communicates with a line 44 which connects with actuating chambers (not shown) of brakes 21 of the vehicle. In the "vent" position of directional control valve 16 in FIG. 1, line 44 will be vented to tank 13, as more fully described hereinafter, whereby brakes will remain in their "on" condition of operation.
Line 36 is further connected to a line 45, having a check valve 46 connected therein with line 45 being further connected to directional control valve 16. Line 45 also connects with tank 13 via a restricted orifice 48 which is primarily utilized to compensate for any leakage occurring in valve 16. A line 49 is utilized for resetting the control circuit to prevent energization of transmission 18 when directional control valve 16 is maintained in its "run" position upon starting of the engine.
In particular, FIG. 2 illustrates a first valve means 50 of a reset means which must be moved to its FIG. 4 reset position before pump means 17 can be actuated to drive motor M. As more fully described hereinafter, any attempt by the operator to start the vehicle when directional control valve 16 is in its "run" condition of operation would be to no avail since replenishing valve 43 of transmission 18 (FIG. 1) will remain connected to tank 13. In addition, brakes 21 will remain in their "on" condition of operation to prevent the vehicle from being moved, as also described hereinafter.
Valve means 50 comprises a spool 51 having a restricted passage 51a formed therein, suitably mounted for reciprocal movement in a housing 52 of the transmission control group and is spring biased leftwardly to its first or closed position in FIG. 2 by a first coil spring 53. A less stiff second coil spring 54 is mounted between the spool and a tubular sleeve 55, mounted on the end of the spool by a pin and slot connection 56. Pressurization of line 49 to move spool 51 rightwardly towards a second, open position will thus initially compress spring 53 to engage the right end of sleeve 55 with housing 52 (FIG. 3) whereafter spring 54 will compress along with further compression of spring 53 to subsequently engage the right end of spool 51 with the housing (FIG. 4). This "delayed action" of first valve means 50 assures conditioning of the control circuit for operation, including the desired operation of the reset means, as described more fully hereinafter. As shown in FIGS. 3 and 4, once reset valve 50 has been opened by pressurizing an actuating chamber 57 via line 49, pressurized fluid in line 45 will be communicated to the chamber via internal passages 58 and 59 and restricted passage 51a to maintain the spool in its second, open position. It should be noted that passages 58 and 59 preferably have restrictions 58a and 59a therein, respectively.
FIG. 2 further illustrates a second valve means 60 of the reset means comprising a spool 61 biased rightwardly to its first, open position to normally vent line 44 to tank 13, via interconnected internal passages 62 and 63 when control valve 16 is maintained in its FIG. 1 "vent" position. Referring to FIG. 3, when pressurized fluid is communicated to the right end of spool 61 via line 45 and passage 58, the spool will move leftwardly to a second, closed position to block communication between passages 62 and 63 and to open communication between lines 44 and 45 via internal passages 62 and 64.
As more fully described hereinafter, spool 61 is maintained in this closed position when spool 51 moves further rightwardly to its FIG. 4 position by communication of pressurized fluid to the rightward end thereof from chamber 57, via passages 59 and 58. Thus, from the above description it can be seen that when directional control valve 16 (FIG. 1) is maintained in its "reset" or "run" position, normally "on" brakes 21 will be released. Furthermore, replenishing valve 43 of transmission 18 is simultaneously placed in communication with pressurized line 45, via line 44.
As further shown in FIG. 2, override valve 28 comprises a spool 65 rotatably mounted in housing 52 to normally block communication between a pair of passages 66 and 67, the latter passage communicating with a line 68. Passages 66 and 67 are adapted to intercommunicate when the spool is rotated to an open position to change the differential fluid pressure prevalent as between lines 30 and 31 to override the operation of the primary control means comprising speed control lever 14, directional control valve 16 (FIG. 1) and underspeed actuator 23. As shown in FIGS. 6 and 7, rotation of spool 65 in a clockwise direction past an angle "a" relative to housing 52 will initially communicate passages 66 and 67, via radial passages 69 and 70 and a longitudinal passage 71 formed in the spool. Further clockwise rotation of the spool past angle "b" in FIG. 5 will function to vent actuating chamber 57 to tank 13, via passage 59, a radial passage 72 formed through the spool and a passage 73.
As described more fully hereafter, directional control valve 16 (FIG. 1) must be first repositioned to its "reset" position and then to its "run" position before the control circuit can be reconditioned for control of the displacement of pump means 17. However, so long as the spool is not rotated to the extent of angle "b" (FIG. 5), the spool can be returned to its closed position to reinstate the normal operation of the control circuit (with directional control valve 16 remaining in its "run" position). It should be further noted that a pair of metering slots 74 (FIG. 7) are formed in spool 65 at the ends of passage 70 to closely control the desired change in the fluid pressure signal which automatically controls the operation of underspeed actuator 23.
During the override condition of operation and referring to FIG. 2, the controlled interchange of fluid between passages 66 and 67 will thus effect the differential pressure or signal occasioned across venturi 25 since passage 66 communicates with line 31. Passage 66 is connected to line 31 on a downstream side of a fixed orifice 75 which communicates with a throat 76 of venturi 25 via a radical port 77. It should be noted that passage 67 further communicates with line 68 which is, in turn, connected to line 33 of the underspeed control arrangement, including underspeed valve 23 and quick response valve 34.
It should be further noted in FIG. 2 that when spool 51 of the reset means is in its closed position that passages 66 and 67 are interconnected via passages 78 and 79 and an annulus 80. Thus, an equal pressure is communicated to either side of underspeed actuator 23 via lines 32 and 33 (FIG. 1) to move spool 23' to a zero speed condition of operation. When spool 51 is moved to its FIG. 4, open position, communication between passages 78 and 79 is blocked and passages 66 and 67 can only communicate with each other upon rotation of spool 65 to override control valve 28 to override the fluid pressure signal communicated to underspeed actuator during normal operation. Since the underspeed actuator is connected to servo system 26 of pump means 17 by linkage 24 (FIG. 1), it is desirable to always make certain that the linkage on the actuator is at a zero input condition whenever the vehicle is at rest or the control circuit is being overridden in the above-described manner by override control valve 28. Such zero input condition relates to the input to servo system 26.
INDUSTRIAL APPLICABILITY
As indicated above, the fluid control circuit of this invention finds particular application to hydrostatic transmission 18 (FIG. 1) which may be employed in a construction vehicle such as a track-type tractor. Although the transmission is shown with a single pump and a single motor, it should be understood that normally a pair of each are employed in the vehicle.
Assuming that the engine of the vehicle is running to drive pump 11 and that speed control lever 14 is in its "vent" or "V" position illustrated in FIG. 1, pump pressure, as established by relief valve 35 and the pressure drop across venturi 25, will be communicated to inlet 29 of venturi 25 to charge the control circuit with pressurized fluid. During this condition of operation, vehicle brakes 21 are held in an "on" condition of operation since line 44 communicates with tank 13 through valve means 60 via passages 63 and 63 (FIG. 2). As suggested above, brakes 21 may be of conventional design wherein springs (not shown) normally hold the brakes in their "on" condition of operation and the brakes are released by communicating pressurized fluid to actuating chambers thereof.
Line 44, common to brakes 21 and replenishing valve 43, will simultaneously communicate the valve with tank 13. The parallel lines comprising loop 19 of transmission 18 are thus interconnected or "shunted" whereby the transmission is rendered non-operational in a conventional manner.
Also, during the "vent" condition of operation, it is assumed that foot pedal 27 has not been depressed to thereby maintain override valve 28 in its inactivated or closed condition of operation with passages 66 and 67 being maintained out of communication, as shown in FIGS. 6 and 7. The pressure differential or signal thus occasioned as between lines 30 and 31 will be communicated to either side of underspeed actuator 23 to ready the control circuit for normal operation. Pressure regulating valve 35 will maintain a predetermined back pressure on the downstream side of venturi 25 (e.g., 350 psi) whereas pressure relief valve 42 will function to charge line 37 and replenishing valve 43 with fluid maintained at a predetermined pressure (e.g., 150 psi). It should be further noted in FIG. 2 that spool 51 of valve means 50 is positioned to block line 45 and that directional control valve 16 is in its "vent" position (FIG. 1) to block communication between lines 45 and 49, the latter line leading to actuating chamber 57 of the reset means comprising valve means 50 and 60.
When the operator now shifts speed control lever to one of the two "reset" or "R" positions in notch 15 (FIG. 1), directional control valve 16 will responsively move downwardly one position to communicate pressurized fluid from line 45 to line 49 to charge actuating chamber 57 (FIG. 3) with pressurized fluid to initiate rightward movement of spool 51.
As shown in FIG. 3, initial movement of spool 51 rightwardly will communicate line 45 with chamber 57, via restricted passage 51a. Thus, once such communication is established, spool 51 will continue to move rightwardly even though the operator should quickly shift lever 14 and control valve 16 into their "run" positions. It should be noted that pressurized fluid in line 45 is further communicated to chamber 57, via passages 58 and 59.
As discussed above, rightward movement of spool 51 is in two stages in that the spool will initially compress spring 53 to engage the rightward end of sleeve 55 with housing 52 (FIG. 3) and will thereafter compress both springs 53 and 54. Spring 53 may be calibrated to permit spool 51 to move rightwardly to its FIG. 3 position when the pressure level in the chamber reaches 20 psi, for example. Full opening of spool 51 to its FIG. 4 position may require a pressure level at least 115 psi in chamber 57, for example.
The above sequence and delayed opening of valve means 50 will insure full actuation and closing of valve means 60. In particular, when spool 51 has moved to its intermediate "reset" position illustrated in FIG. 3, pressurized fluid will be communicated to the right end of valve spool 61, via lines 45 and 58. Spool 61 will thus begin to move leftwardly against the counteracting force of a spring 61a when the fluid pressure at the right end of spool 61 reaches 115 psi.
Upon full movement of spool 51 to its FIG. 4 position, the spool will permit limited communication of line 45 with passage 58 and the rightward end of spool 61. Chamber 57 is also maintained in communication with passage 58, via restricted passage 59, to communicate sufficient fluid pressure (e.g. 115 psi) to the rightward end of spool 61 to maintain it in its FIG. 4, closed position. Simultaneously therewith, spool 61 will block communication between passage 62 and drain passage 63.
Pressurized fluid now freely communicates from line 45 to line 44, through valve means 50 and 60, to release brakes 21 and to permit charging of replenishing valve 43 (FIG. 1). The operator may now shift speed control lever 14 to a "run" position (reverse or forward), along with slaved directional control valve 16, whereby lines 45 and 49 are blocked from each other and the circuit remains pressurized for actuating pump means 17 of hydrostatic transmission 19. As suggested above, orifice 48 (FIG. 1) is suitably sized to primarily function to compensate for any leakage that may occur in valve 16 and will maintain the desired back pressure (e.g., 150 psi) in lines 44 and 45 for operational purposes.
In the "run" condition of operation, the afore-described pressure differential across venturi 25 will function to condition underspeed actuator 23 (FIG. 1) for operation of servo system 26 of pump means 17 in a conventional manner. As described in above-referenced U.S. Pat. No. 3,996,743, lines 32 and 33 will communicate a differential pressure across underspeed actuator 23 to automatically control the operation of servo system 26, via a standard linkage 24. Since such pressure differential is generally proportional to the operating speed of the engine and pump 11, increasing or decreasing the speed of the engine will result in a corresponding change in the pressure differential to closely control the operation of pump means 17 and, in particular, the displacement of pump P thereof.
As further described in U.S. Pat. No. 3,996,743, operator movement of speed control lever 14 to place directional control valve 16 in a selected "run" position will simultaneously reposition piston 23' of underspeed actuator 23, via standard linkage 22. Shifting of the piston to an extreme position will provide for relative maximum displacement of pump P, as well as maximum operating speed of motor M, and is commonly referred to as "zero underspeed". Movement of speed control lever 14 to its other extreme position in the "run" condition of operation will move piston 23' of underspeed actuator 23 to an opposite extreme position and condition the hydrostatic transmission for "full underspeed" operation.
It should be understood that the engine is mechanically connected to drive pump P and when the pump is driven at rated or optimum speed by the engine, fluid output from positive displacement pump 11 will be substantially constant. Fluid flow across throat 76 of venturi 25 (FIG. 2) will create the above-described pressure differential, as between lines 30 and 31, and when speed control lever 14 is set in its maximum speed position during the "run" condition of operation, underspeed actuator 23 will be shifted towards its "zero underspeed" position. However, as the vehicle and transmission 19 encounter an increased load or increased resistance to movement to cause "lugging" of the engine, operating speed of pump 11 will decrease with a resultant decrease of fluid flow through venturi throat 76.
A relative pressure increase in line 31 thus results. This increased relative pressure will function to actuate the underspeed valve in proportion to the amount of relative pressure increase within line 31. Accordingly, the displacement of pump P is decreased to thereby reduce the torque requirements for driving the pump by the engine until such torque requirements equal the torque output of the engine at an instantaneous reduced speed. Should the increased resistance remain constant for a period of time, underspeed actuator 23 will remain balanced intermediate the "zero underspeed" and "full underspeed" conditions of operation.
When the increased load is relieved, the engine is permitted to regain its rated operating speed with pump 11 also returning to its normal operating speed. At such time, normal fluid flow through venturi throat 76 re-establishes the original pressure differential in conduits 30 and 31 so that underspeed actuator 23 may be again shifted toward its "zero underspeed" position.
As discussed above, quick response valve 34 is suitably interconnected between venturi 25 and an upstream side of underspeed valve 23 in order to provide a slow recovery rate for the underspeed condition when the engine is coming up to its full operational speed, but to provide a quick down action of the underspeed to drop from a predetermined maximum speed to a lower or zero speed condition.
When the operator desires to override the operation of speed control lever 14, when it is in its "run" position of operation, he need only depress pedal 27 to rotate the spool 65 of override control valve 28 clockwise in FIGS. 5-7. Ax explained above, the override control valve will function to change the pressure differential as between lines 32 and 33 which normally controls the operation of servo system 26 of pump means 17. In particular, sufficient rotation of the spool past angle "a" (FIG. 6) to interconnect passages 66 and 67 via passage 71 will cause underspeed actuator 23 to "move down" to thus reduce the displacement of pump P the desired amount. As shown in FIG. 7, the change in the pressure differential can be closely controlled by metering slots 74.
Should the operator depress pedal 27 to its full override condition of operation, past angle "b" in FIG. 5 whereby passage 72 connects line 59 with drain line 73 and tank 13, chamber 57 (FIG. 2) will be exhausted to permit spool 51 of valve means 50 to move leftwardly to its inactivated or closed position. Simultaneously therewith, line 58 will exhaust to permit movement of spool 61 fully rightwardly (FIG. 2) to exhaust the actuating chamber of brakes 21 (FIG. 1), via line 44 and passages 62 and 63. Thus, the operator must return speed control lever 14 and directional control valves 16 to their reset positions before brakes 21 can be re-released and transmission 18 reactivated for driving the vehicle. Likewise, should the operator turn the engine off and again attempt to restart the engine with speed control lever 14 in a "run" position, he must also return to the above-described reset positions of the control lever and directional control valve 16 prior to activation of transmission 18.
As shown in FIGS. 5-7, the operator may effect the normal override function by rotating spool 66 through an angle of "b" minus "a". Should such an angle be exceeded, the operator must return speed control lever 14 to its reset position in the manner described above. However, so long as the operator remains within this range, he may release foot pedal 27 whereby the control circuit will return to normal operation, with control lever 14 having been retained in its original "run" position in notch 15 (FIG. 1).
Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims.
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A fluid control cirucit for selectively varying the displacement of a variable displacement pump (P), such as the type employed in a hydrostatic transmission, comprises a primary control circuit connecting a pressurized fluid source (10) with the pump (P) and adapted to be actuated to selectively vary the displacement of the pump (P) between minimum and maximum values. A separate override control circuit is connected to the primary control circuit to override it to selectively vary the displacement of the pump (P).
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FIELD OF THE INVENTION
This invention relates to methods and apparatus for producing multiple sections from a hot steel billet or bar by progressive rolling passes in a steel mill. The general process of producing multiple separated elemental strips of steel is referred to as slitting.
BACKGROUND OF THE INVENTION
Reduction of steel billets or blooms in a steel mill to a finished product (e.g. rod or wire) is a time consuming and expensive operation involving the use of costly equipment.
Typically, a billet is reduced to a work product which becomes longer and longer with each pass. Because of the elongation involved in the reduction of the billet, the bar or rod may be cropped into smaller lengths which can be processed individually without requiring the whole billet work product to pass through and be stored on coiling apparatus at either side of the reduction rollers.
In order to reduce the quantity of steel product which must be passed through the reduction stages of a reducing rolling mill, operators have sought methods of slitting a reduced billet into a plurality of parallel sections after a predetermined number of passes (usually 10) in a primary reduction process. The work product is slit into two (usually) pieces which may be processed in a parallel finishing operation, as opposed to causing the work product to be completely finished in one continuous piece.
Typically, a well known prior art method of reduction employing a slitting operation in general use, at the present time, requires that a steel billet be reduced to a "fluted square" in a predetermined number of passes (usually 10) in a primary reduction mill.
The fluted square is rolled into what is generally referred to as a "dog bone" shape which is reduced to a "peanut" shape in two rolling steps.
The peanut shape of the steel workpiece lends itself to slitting because of the narrow web holding the two substantially circular sections of the peanut together.
Thus, the single peanut is slit with two separate strands (or sections) which may be processed in a parallel reducing operation to yield a finished product.
Most steel mill operators agree that the use of a slitting operation is more efficient than employing rolling reduction to achieve the same reduction in cross sectional area of the workpiece.
But slitting, by means of the prior art, is not without ensuing problems. The process, just described, produces only two workpieces which may be processed by a parallel processing operation. If an attempt is made to increase the number of sections of separated parallel workpieces, problems may arise because of the adverse material flow in forming the hot steel workpiece. The adverse flow results from forcing the hot steel product to flow in directions other than the direction of rolling in order to produce the complex shape of the hot steel workpiece which is to be subsequently slit into four or five parallel sections. Problems also arise due to uneven temperature distribution in the resulting slitted workpieces which result in difficulty in subsequent rolling required to achieve the final shape in the finished product, resulting in the production of an inferior product.
The "dog bone"-"peanut" slitting operation itself requires moving the hot steel product through four rolling stands and (usually) eight separate mill guides, to successfully produce the separated product sections. A malfunction in any one of the eight guides may lead to an interruption in the production of the slitted workpiece. Those familiar with the process are well aware of the hostile nature of the environment in which these guiding devices must operate.
Methods other than the "dog bone"-"peanut" production procedures have been employed by steel mill operators with varying degrees of success.
At times, when the plurality of sections of different cross sectional area are formed in a workpiece prior to the actual slitting operation, the acceleration forces to which the various sections of the workpiece are subjected are sufficient to cause premature fracture of the web holding the sections together, or if the workpiece remains intact, it tends to undergo severe curvature as it exits from the rolling mill. Problems, arising from such operations, result in lower quality finished product and at times the generation of scrap.
Slitting with wedge shaped cutters may also produce an end product having undesirable camber (see U.S. Pat. No. 4,370,910) which may yield a section which is subsequently difficult to roll. As well, some rolling processes cause an adverse material flow in the web of the section being slit in a directions other than in the direction of rolling. This undesirable material flow in the web yields a product the physical characteristics of which may be somewhat impaired.
At other times, steel mill operators have developed sophisticated methods of twisting the hot steel product before it is passed into the slitter-rollers. The twisting of a hot steel product requires the use of equipment, which in prior art installations, is subject to wear and may be prone to failure because of the nature of the operation being carried out on the product passing through the mill. At other times, the slitting operation requires the addition of other rolling accessories to "straighten" the product.
SUMMARY OF THE INVENTION
The process of this invention begins at the conclusion of the reduction of the billet or bar in ten reduction stages. Passage through the eleventh stand produces a bar having a rectangular cross section. The rectangular cross section will have dimensions which vary according to the number of strands being produced. For the production of 4 strands, the width may be about 10-11 times the height of the bar. Other dimensional configurations will be required for the production of a different number of strands.
Stand number twelve produces a bar having slightly greater width than it had upon entrance because a series of longitudinal opposing grooves have been rolled into the bar during passage through millstand twelve.
Passage through millstand 13 produces a bar which now has a plurality of divisions extending in the direction of rolling, so that each section is more isolated from its adjacent section by a deep groove, but as yet the sections remained joined by a narrow web.
Millstand 14 produces separation of the sections by producing a "twist" into each section, so that each section undergoes a slight twist in the same direction of rotation during passage through this millstand. The adjacent edges of each section are displaced away from each other by the twisting action induced into each section by fluting formed in the rolls of the fourteenth roll stand.
The separated sections, which have an elongated oval shape, are allowed to twist through a right angle before entering the fifteenth roll stand where a round or other desired cross section is produced.
The separation of the bar which was produced at the eleventh millstand may be accomplished by applicant's apparatus to produce as many as six separated webs of the hot steel product.
PERTINENT PRIOR ART
U.S. Pat. No. 281,184 Jul. 10, 1983
This patent divides a billet into a series of sections in opposite directions from a common central plane by progressive rolling steps. When the adjacent sections are displaced sufficiently so that each section is joined to its adjacent sections by a small longitudinal web, the billet sections are pushed back into the central plane to break the longitudinal webs between adjacent sections to produce the separated sections.
U.S. Pat. No. 885,508 Apr. 21, 1908
This patent subjects a hot steel billet to a number of passes in a mill in order to produce deep parallel channels in the billet. The sections of the billet which, lying within the channels, are then subjected to different rates of reduction during a rolling process to produce differing exit velocities between the adjacent sections so as to fracture the web existing between the sections formed by the channels to produce separated sections between the previously joined channels.
U.S. Pat. No. 4,204,416
By passing a billet between opposing rollers having V shaped rings protruding from the roller surface, this patent describes a process for reducing a billet to a number of joined sections each having rectangular cross section but where the sides of the sections are formed so as to make an angle of about 45° with the rolling axis due to the V shaped rollers. By suitable reduction, the various rectangularly shaped sections are shifted to reduce the web between adjacent sections and separate the sections.
U.S. Pat. No. 4,357,819
This patent describes the method of producing three separate sections by a modified "dog-bone"-"peanut" rolling sequence.
U.S. Pat. No. 5,626,044 May 6, 1997
This patent describes a method of producing sections of unequal cross section prior to slitting of the sections. Because some of the sections (i.e. outermost) must travel increased distances after separation, these sections tend to be stretched somewhat. These sections (which must travel the greatest distance after separation) have been rolled so that they have slightly larger cross sectional area. These sections are subjected to a greater tension force and tend to be reduced in cross section during the stretching procedure. The separated sections may then be simultaneously rolled in the same mill stand after separation without having greatly differing exit velocities.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the classical steel mill apparatus used for slitting a bloom or billet to a finished circular cross section using techniques of the prior art.
FIG. 2 shows the rolling sequence of this invention which is used to produce a plurality of sections of circular cross section from a flat slab produced from the original billet.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1 which shows a sequential rolling process for reducing a "fluted square" to a pair of rods or wires having a circular cross section in four reducing rolling operations. The "fluted square" steel billet 10, which has a classical shape, is shown having exited from millstand #12 in a modern billet reducing mill. The member 10 is twisted through an angle of about 45° as it passes through a twister delivery guide 12 to take the orientation shown at 14. The twisted "fluted square" member 14 which exits from the twister guide 12 with new orientation is now passed through a roller entry guide such as 16 which maintains the correct orientation of the member 14 for subsequent passage through the thirteenth millstand 18 which produces "dog-bone" shaped member 20. Dog-bone shaped member 20 subsequently passes through a static delivery guide 22 which assures that dog bone 20 does not exit from millstand 18 improperly. After passage through static guide 22, the dog bone 20 enters entry guide 24 which traditionally is a four roller entry guide where dog bone 20 is passed into the fourteenth millstand 26. Here a "peanut" member 28 emerges from millstand 26. At this stage, the two substantially circular cross sectioned members joined together by a very narrow web comprising the "peanut" 28 are passed through slitter guide 30 to fracture the small connecting web and produce two separated substantially circular sections 32 and 34. The individual members 32 and 34 are separated and each member is passed through a static entry guide such as 36.
Thus, each of the separated sections 32 and 34, are reduced into an oval cross section in member 38 in the fifteenth millstand 40. Each oval member 38 passes through a twister delivery guide 42 which twists the member 38 through 90°. The twisted member 38 is fed into a four roller entry guide 44 which passes oval member into the sixteenth millstand 46.
At millstand 46 the previous oval shaped cross section member 38 becomes a round rod or wire 48.
This process involves four millstands and eight mill guides of which two of the guides are "twister" guides.
The disadvantages of such prior art slitting operations are many and varied. The completed product (wire or rod) requires 16 millstands to produce two strands of the final product.
Two of the guides required for the slitting operation are "twister" guides which are subject to increased wear and maintenance in the hostile environment in which they perform their function.
This traditional method of slitting can successfully produce only 2 separated sections. If more separations are attempted, the separated sections are difficult to roll because of the lack of homogeneity in the temperature of the separated sections. The prior art shows such problems (see U.S. Pat. No. 4,370,910).
FIG. 2 shows the preferred process for producing four sections from a rectangularly shaped bar 100 having a height to width dimensional ratio of about 1:3 for each separated section produced. For instance, to produce 4 strands, the ratio will be 1 to 11 or 12. Bar 100 is shown having just exited from the eleventh millstand having been reduced by rollers 102 and 104. The width to height ratio of bar 100 is about 11:1. Bar 100 comprises a standard shape which is relatively easy to roll and no exit guide is required for the bar 100 leaving the eleventh mill stand.
At the twelfth millstand, bar 100 is grooved to produce four sections 106, 108, 110 and 112 separated by depressions 114, 116, 118, 120, 122 and 124. These depressions are produced by rollers 126 and 128 which captivate the bar 100 in the gapped openings formed therein. The formation of channels 114 through 124 does not produce any significant exit velocity differentials between the sections 106, 108, 110 and 112 so the grooved bar 100 tends to exit from the twelfth millstand in a straight line and thus the tendency for the channeled billet 100 to curve or separate the adjoining sections upon exiting from millstand 12 is virtually non existent.
The channeled billet 100 is passed from the twelfth millstand and into the thirteenth millstand where a plurality of sections 130, 132, 134 and 136 of elongated oval shaped cross section are produced. Each of the above sections is connected to its adjacent section by webs 138, 140 and 142 which are very narrow. This configuration of sections 130-136 is produced by rollers 144 and 146 which have mating protruding rings which co-operate to form the four still joined sections 130-136.
The production of sections 130-136 is very important for a number of reasons. The particular flow of the hot metal product to produce the four sections 130-136 is produced with a minimum of rolling energy. The flow of metal in each section is much the same for each section (i.e. from the edges of the oval shaped section toward the center) and also simultaneously in the direction of rolling. This flow does not cause wide variations in the exit velocities of the sections 130-136 so that the joined sections of the billet 100 do not tend to separate prematurely. Curvature of the complete channeled billet 100 tends to be minimized, thus the need for exit guides at this stage of rolling is really not necessary.
The segmented but still joined billet 100 is passed from the thirteenth millstand to the fourteenth millstand where a four roll entry guide will generally be used to guide the channelled billet 100 into the fourteenth millstand. At the fourteenth millstand, a pair of rollers 148 and 150 whose surface profile has a "sawtooth" shape now engages the nearly separated sections 130, 132, 134 and 136. Rollers 148 and 150 are provided with a series of ramped teeth 152, 154, 156, 158 and 160, 162, 164 and 166 respectively. Each of the above teeth has adjoining sloping surfaces 168, 170, 172, 174 and 176, 178, 180 and 182 formed integrally therewith. Rolls 148 and 150 offset so that the sloping surfaces such as 168 and 176 co-operate to engage and twist section 130 counter clockwise. Simultaneously, the surfaces 170 and 178 of rolls 148 and 150 respectively engage and twist section 132 in a counter clockwise direction during passage therebetween. Sections 130 and 132 now separate as do the other sections 134 and 136.
Rollers 148 and 150 are situated so that the two "sawtooth" surface profiles are mated together, to form parallelogramically shaped recesses 184, 186, 188 and 190 between them.
The recess 184 is formed of sloping sides 168 and 176 and straight sides 154 and 155.
It must be remembered that the sawtooth profile of rollers 148 and 150 are actually protruding rings of a frustro-conical configuration on each of the rollers which must be provided by a grinding operation. The rollers have cylindrical surfaces separating the frustro-conical rings. These profiles are not difficult to produce in practise.
It is the positioning of the rolls to produce the parallelogramically shaped recess between the rolls 148 and 150 which leads to the efficient separation of the sections 130, 132, 134 and 136. For instance, the two sloping surfaces 168 and 170 of rolls 148 and 150 respectively which form part of recess 184 gradually separates the sections 130 and 132 during passage through the fourteenth millstand and leave each section such as 130 slightly twisted as it exits the fourteenth millstand.
Each of the oval shaped sections 130-136 is allowed to twist through a right angle as it exits the fourteenth millstand in the absence of any guides. The sections 130-136 are fed to the fifteenth millstand having rollers 192 and 194. Rolls 192 and 194 are provided with four circular caliber openings 196, 198, 200 and 202. Sections 130-136 have now obtained a circular cross section.
The slitting operation is precise and accurate with each separated section being slit without any substantial deformation having been undergone by each section during the slitting operation. This assures that each section emerges from the slitter with the same twist and exit velocity. Problems with loop control and curving of the workpiece is avoided.
It will be noted, that the separation of the strands is achieved without having premature strand separation or adverse material flow.
This process requires the presence of no "twister" or "straightening" guides. Most guides, which will be used, are stranded multi roller entry guide types.
This invention may be used to produce a wide variety of the number of separated strands of the steel work produce.
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A slitter for a steel mill comprising a pair of spaced rollers having a predetermined surface configurations. A deeply grooved steel workpiece is passed through the gap in the spaced rollers and each section of the workpiece (between the grooves) is twisted through a small angle. Because each section is twisted in the same direction, the workpiece fractures along each groove in the workpiece.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. patent application Ser. No. 11/046,028, filed on Jan. 27, 2005, abandoned, which is a continuation of U.S. patent application Ser. No. 10/090,295, filed on Mar. 4, 2002, abandoned, which is a continuation of U.S. patent application Ser. No. 09/731,590, filed on Dec. 7, 2000, now U.S. Pat. No. 6,358,051, which claims priority to and the benefit of U.S. Patent Application Ser. No. 60/169,546, filed on Dec. 7, 1999.
This invention was made with government support under grant number 1R43DE13454 awarded by National Institutes of Health Office of Extramural Programs SBIR/STTR Grant Programs. The government has certain rights in the invention.
BACKGROUND
This invention relates to a method and apparatus for ensuring that small screws used to hold together dental implant components are tightened to the correct initial stress level, or “preload.” According to the National Institute of Health, among the factors involved in the design of a dental implant are the forces produced during implant loading, the dynamic nature of loading, and the mechanical and structure properties of the prosthesis in stress transfer to tissues. Unfortunately, accurate data on such parameters are incomplete. National Institutes of Health Consensus Development Conference Statement on Dental Implants. June 13-IS, 1988.
During the early 1970's the dental profession was very hesitant to use dental implants or fixtures surgically implanted into a patient's jawbone as a treatment option to replace missing teeth. However, success with implants in the past 30 years has replaced this skepticism. This is due to the efforts of P-I Brånemark and co-workers in Sweden who introduced the concept of osseointegration in humans. When the principles of osseointegration are followed, the anchorage of a non-biological titanium implant unit to living bone will occur, with approximately 95% and 85% implant survival rates for the lower and upper jaws, respectively. See, for example in U.S. Pat. Nos. 4,824,372, 4,872,839 and 4,934,935 to Jorneus et al., Brajnovic and Edwards, respectively.
One of most critical aspects in the replacement of missing teeth using dental implants is the ability of small screws positioned within the implant complex to hold the various implant parts together during loading and stress transfer. As any screw in the implant system is tightened, the initial stress level developed within the screw becomes critical to the maintenance of the joint stability between the parts the screw is clamping together. Owing to the high strain level that the assembled joint experiences in everyday life, this initial stress level called the preload is of paramount importance. Insufficient tightening of a screw in the implant system can result in the screw becoming loose rather quickly, and over time this looseness can lead to fracture of the screw and potentially failure of the implant reconstruction. This is particularly critical for screws that secure spacers or abutments to the implant or fixture.
The stability of the screw joint is considered a function of the preload stress achieved in the screw when applying the preload tightening torque to clamp the implant components together. The optimum preload torque is influenced by the geometry of the screw, the contact relationships between the screw and its bore, between the screw and its threads, and between the bearing surfaces of the components clamped together by the screw, friction, and the properties of the materials used. One example is the joint formed between the bearing surface of the implant and the bearing surface of the spacer or abutment. Another example is the joint formed between a prosthesis and an abutment, also held together by a small screw in the implant system.
When the screw joint experiences instability, the screw will either loosen or fracture. Screw joint failure occurs in two stages. The first stage consists of external functional loading applied to the screw joint that gradually leads to the effective erosion of the preload in the screw joint. Any transverse or axial external force that causes a small amount of slippage between the threads releases some of the stress, and therefore, some of the preload is lost. The greater the preload applied to a screw joint (up to a maximum equal to the proportional limit), the greater the resistance to loosening and the more stable the joint. As long as the frictional forces between the threads remain large, a greater external force will be required to cause loosening.
Once the critical load exceeds the screw joint preload, it becomes unstable. The external load rapidly erodes the remaining preload and results in vibration and micromovement that leads to the screw backing out. Once this second stage has been reached, the screw joint ceases to perform the function for which it was intended and has failed.
Optimizing the preload of a screw used in a dental implant system is critical for implant screw joint stability. As was stated earlier, implant screw loosening and fractures are quite common. The fact that on average complications with implant screw will occur in one out of every four implants surgically placed is significant. The need for optimum preload in screw tightening at the initial stages of implant component assembly and completion of the final implant restoration cannot be left to chance. An instrument that scientifically records the preload established in these implant screws following tightening and prior to any external load applications is essential to implant performance and the quality of life of the patient who receives implants as part of their dental rehabilitations.
It has been reported by Patterson and Johns that to achieve the maximum preload possible in component screws for dental implants, it is necessary to apply the appropriate tightening torque to each screw. Torque tightening devices for implant screws are discussed, for example, in U.S. Pat. Nos. 6,109,150 and 5,626,474. However, most screw torque-tightening devices lack accuracy because of a number of variables beyond the control of these conventional instruments. This means that the maximum stress developed in an implant screw tightened by conventional torque-tightening devices may be less than 70% of the yield strength of the screw itself and therefore well below the maximum possible preload for a stable joint. If the screw is loaded to the appropriate preload level one can be confident that the screw will not fail during the life of a patient when “normal” external loads are applied.
Ultrasound instrumentation has been used to measure the preload established in large bolts and screws in industrial applications. Thus far, however, it has not been applied to small screws the size of those used in implant systems. In industrial applications for large bolts and screws, the most common ultrasonic instruments for control of screw tension are called “pulse-echo” or “transit time” instruments. Bickford has described the use of this method with large bolts. A drop of fluid is placed on the head of the bolt to reduce the acoustic impedance between the transducer and bolt head. An acoustic transducer of some sort is placed against the bolt head. The instrument is then zeroed for this particular bolt because each bolt will have a slightly different acoustic length even if their physical lengths are the same. The zero load is recorded before tightening. Next, the bolt is tightened. If the transducer can remain in place during tightening, it will show the buildup of stretch or tension in the bolt during tightening. If it must be removed, it is repositioned on the bolt again after tightening to show the stress level achieved. If at some future time one wishes to measure the tension present within the bolt, the original data can be input to the instrument computer unit and after placing the transducer on the top of the bolt, the instrument will record the existing tension and the zero stress conditions.
In principle, the electronic instrument delivers a voltage pulse to the transducer, which emits a brief burst of ultrasound (typically five to seven or more cycles). This burst passes down through the bolt, echoes off the far end, and returns to the transducer. The electronic instrument measures very precisely the time delay required for the burst of sound to make its round trip in the bolt. As the bolt is tightened, the amount of time required for the ultrasound to make its round trip increased for two reasons: 1) the bolt stretches as it is tightened, so the path length increases, and 2) the average velocity of sound within the bolt decreases because the average stress level has increased. At low strain those functions can be approximated by linear ones of the preload in the bolt, so the total change in transit time is also a linear function of preload.
In dental implant technology, it is important to know what preload exists in implant screw joints at any time during implant therapy and throughout the life of the implant.
All of the currently used implant screws are fabricated from materials that are nontransparent and nonmagnetic. No other efficient technique for stress measurements of nonmagnetic and nontransparent materials is available. In contrast, a magnetic hysteresis curve can be used to infer the stress in magnetic materials, and also optical coherent methods can be used to infer the stress in transparent materials. However, the accuracy of this latter method is significantly lower than that of the ultrasonic TOF measurements, and as stated the implant screws are made of nonmagnetic materials. The use of mechanical methods for stress measurements requires exact measurements of the length of the implant parts, and with the 30 plus implant manufacturers throughout the world and their reluctance to provide this data, this method has definite limitations.
Ultrasonic measurement of the stress in a screw or bolt with a relatively big cross-section and length has been known for some time. Since the early fifties the technique has been theoretically and experimentally proven for a range of materials. Experimental and theoretical results obtained by Huges and Kelly on samples of rail steel with various load conditions have shown the proportionality between the uniaxial stress and velocity of acoustic waves. However, since then the method has been used for only relatively long and large cross-section components, partially due to an insufficient accuracy of TOF measuring devices. At present a digital oscilloscope's sampling rate ranging to several gigahertz makes possible a real time measurement of time intervals with the 10-100 picosecond accuracy. As to the dental implant screw in question, the ultrasonic evaluation of the stress via the time of flight measurement in principle is feasible. In practice the method is not straightforward and several factors have the potential to influence the accuracy, however, the whole performance is predictable. Difficulties reside in the small size transducer required (around 0.5 mm. active element diameter), and the small length inducing a low variation of the time of flight of the ultrasonic pulse. The smaller the transducer, the greater the exposure to a stronger mechanical stress. The smaller the length of the screw, the less variation in the time of flight and consequently the lower precision of the stress measurement obtained. Ambient temperature influencing elastic properties of materials, could also be a concern, which can be controlled.
The optimum preloads suggested for implant screw joints are a percentage of the yield strength of the screw. For example, 50-60% of yield has been suggested for average nongasketed joints, with “normal” safety or performance concerns. A 70-75% of yield has been suggested as the upper limit for nongasketed joints where “low preload” problems have been experienced in the past such as leaks, self-loosening, fatigue, etc. Joints which have had consistent “low preload” problems in the past, and where the need to avoid failure is significant and where service loads (or ignorance of service loads) make it unwise to take the screws any closer to the yield point, a 85-95% of yield has been suggested. Obviously, the preloads suggested for various screw joints demonstrate considerable variation, and depending on the joint requirements, the amount of preload achieved (% of the yield) would be significant in the performance of the joint. Furthermore, the amount of preload suggested depends on the accuracy of knowing the yield point of the screw. McGlumphy has reported significant differences between screws from several implant manufacturers even though the suggested tightening forces, and thus the preload achieved for these screws were the same. The force needed to cause failure in abutment screws for the systems as tested by McGlumphy ranged from 1.22 to 17.23 kg. However, even if the ultimate tensile strength of the screw, the proportional limit and the elastic range were known, neither the preload created by tightening using a torquing device suggested by the manufacturer for the particular screw nor the variability in the preload as a result of the tightening instrument used by the operator is known.
In summary, it would appear that a great deal of subjectivity exists in the tightening of implant screws. It isn't any wonder that screws loosen or fracture. The tightening instruments are a major variable. The quality and quantity of the tightening torque is in question. The “target” preload is uncertain. Finally, the achieved preload is unknown. In implant joints, which are very critical joint assemblies, the stability of the joint begins with knowing the exact preload achieved following the clamping together of the components. The Preload Measurement Gage will provide clinicians with that information.
SUMMARY OF THE INVENTION
This invention provides a method of determining the preload on a screw used in an implant system that secures a component to a fixture or to another component in a dental implant system which comprises the steps of transmitting a sonic impulse at a predetermined frequency to the head of the screw through a transducer when the screw is in an unstressed condition; measuring the delay between the first and second reflections through the unstressed screw, and establishing a baseline value for the unstressed screw; applying a preload of a predetermined value to the screw to secure the implant component in the implant system; transmitting a sonic impulse at a predetermined frequency to the head of the screw through a transducer; measuring the delay between the first and second reflections through the preloaded screw to establish a preload value; and determining the difference in the delay between the baseline value and the preload value, and comparing the difference with a predetermined table of values to determine the preload in the screw.
Transducers used in this invention may be any transducer that transmits and receives sonic impulses. Preferably, the sonic impulse is an ultrasonic impulse. The frequency of the impulse may vary depending on the material characteristics of the screw.
Screws used with this invention may be measured in this manner in the unstressed state before they are packaged and sold, and the baseline value may be provided with the sales information.
This invention also includes apparatus for determining the preload in a dental implant system that includes a fixture having one end adapted for osseointegration into a jawbone, the other end adapted to receive a spacer and including an internal bore that includes threads for engaging with a screw to secure the spacer to the implant, the spacer including an internal bore to receive the screw. The prosthesis may be attached to the implant system with a second screw. The apparatus comprises means for achieving a preload in the screw to secure the component in the implant system, which may be any conventional means, such as a hex wrench or screwdriver, as are commonly sold by companies such as Nobel Biocare, Implant Innovations, or others who market dental implants, abutments, and tools. The apparatus also includes means for transmitting a sonic impulse, which is preferably an ultrasonic impulse, at a predetermined frequency to the head of the screw through a transducer, which may be any apparatus that generates an ultrasonic impulse at the desired frequency. The frequency of the sonic impulse may vary, depending on the material and configuration of the screw. The apparatus also includes means for measuring the delay between the first and second reflections through the preloaded screw to determine a preload value, which may consist of a suitable measurement circuit, which may be in a separate control box, or part of a wand used to transmit and receive the ultrasonic impulse and pulses. The apparatus also includes means for determining the difference in the delay between a pre-established baseline value for the screw and the preload value, and comparing the difference with a predetermined table of values to determine the preload on the screw.
THE DRAWINGS
FIG. 1 is a sectional view of a dental implant installation of the prior art, adapted for purposes of this invention.
FIG. 1A is a sectional view taken along line A-A.
FIG. 2 is a block diagram of one embodiment of the apparatus of the invention.
FIG. 3 is a typical A-scan pattern of pulses generated by this invention.
FIG. 4 is a diagram that demonstrates the principal of the time of flight.
FIG. 5 is a depiction of a preload strain gauge program window for a computer program that may be used in the present invention.
FIG. 6 is a diagram showing configuration windows that may be used with the present invention.
FIG. 7 shows a diagrammatic depiction of a wand that may be used with the present invention.
FIG. 8 is a diagrammatic depiction of a second type of wand that may be used with the present invention.
DETAILED DESCRIPTION
Implant systems, which are well known in the art, generally consist of an implant or fixture, which is surgically implanted into a patient's upper or lower jawbone. As shown in FIG. 1 and FIG. 1A , the fixture 10 includes an externally threaded body 12 , which is surgically screwed into the jawbone. At one end of the body is a flange 14 , which has bearing surface 16 . Body 12 of fixture 10 includes an internal bore 18 , which extends from the flange 14 and which is at least partially threaded to receive an abutment screw (also known as a spacer screw) 22 , which includes a threaded portion 24 , and a head 26 . An abutment 30 includes a bearing surface 32 , which forms a joint 34 with the bearing surface 16 of flange 14 . Abutment 30 also includes an internal bore 36 to receive screw 22 and a flange 38 which is smaller in diameter than the head 26 of abutment screw 22 . The abutment screw 22 passes through the bore 36 of abutment 30 , and the threaded portion 24 of abutment screw 22 mates with the internal threads 20 of internal bore 18 of the fixture 10 . Abutment screw 22 is screwed into the internally threaded bore 18 of fixture 10 , and tightened to a predetermined pre-load to secure the abutment 30 to the fixture 10 .
Head 26 of the abutment screw 22 is provided with an internal bore 40 which has a geometric shape, such as an internal hex, adapted to receive a tool such as a hex wrench for tightening the screw. Other geometric shapes for tools are well known in the art. The abutment screw used for practicing the invention is provided with a reflecting surface at the bottom 42 of bore 40 . A second reflecting surface 44 is provided at the opposite end of the screw. Each reflecting surface is preferably generally flat, and generally perpendicular to the line of transmission of the sonic pulse. Any number of screw head designs may be used, so long as each end of the screw (heads and ends) has a reflecting surface that is sufficiently perpendicular to the ultrasound propagation pathway in order to register and record at a sufficient amplitude the time of flight between two acoustical impulses traveling the length of the screw. All dental implant screw designs can potentially be modified to create a sufficiently reflecting area within and at the base of the head alteration and also at the end of the screw for this purpose. Alternatively, other forms of reflecting surfaces may be used.
In one embodiment of the invention depicted in FIG. 1 , a small 20 MHz PZT element (transducer) 50 of 0.8 mm diameter is fixed to a flattened area 42 in the head 26 of a screw 22 . This transducer 50 provides the interface between the screw 22 and an acoustic source 70 (See FIG. 2 ) for the transmission of an acoustic pulse along the long axis of the screw.
As shown in FIG. 7 and FIG. 2 ., the acoustic source is a hand held wand 70 that is electronically connected to a control box 72 . The electronic connection may be hard-wired 74 , or it may be accomplished remotely, such as by infrared or by so-called “bluetooth” technology, so long as the wand is provided with appropriate infrared transmission and/or receiving means. Alternatively, the control box can be provided in miniaturized form through microelectronics entirely within the handle 76 of the wand 70 .
Within the control box 72 are the electronics needed to initiate an ultrasonic impulse from an acoustic source 78 near the small tip 82 of the wand 70 . The tip 82 of the wand 80 is placed in contact with the transducer element 50 in the head 26 of the screw 22 , which clamps together the abutment 30 and implant 10 to form the screw joint 38 of the implant assembly. A sound impulse is initiated from the tip 82 of the wand 80 and the sound is transmitted by the transducer 50 in the screw head 26 to the opposite end 44 of the screw 22 . Two clear sequential echo-pulses are reflected from the screw bottom (end) back to the transducer and ultimately across the interface to the wand.
The time of flight between pulses 1 and 2 can be determined independent of the acoustic contact variations. The time of flight of the wave propagation through the screw is registered by the transducer 50 and the information is transmitted and processed in the control box 72 by a computer microchip. Tightening of the screw will produced variations in screw length related to the elastic properties of the screw. Screw length variations influence the time of flight of the ultrasonic pulse along the long axis of the screw. The differences in the time of flight recorded before and after screw tightening are used to compute the stress within the screw as a function of screw tightening. The stress is computed by the control box electronics, and displayed both graphically and digitally at the control box 72 .
As shown schematically in FIG. 2 , a system for preload measurement may include, for example, an embedded 20 MHz ultrasonic transducer 50 , an ultrasonic pulser-receiver USD-15 (Krautlramer) 72, a digitizing oscilloscope TDS-520 (Tektronix) 73 connected to a GPIB port (IEEE488) 75 with computer 77 . As is discussed above, the implant screw is provided with a generally flattened surface inside the tool-receiving bore in order to accommodate a 1 mm diameter piezoelectric piston. A piezoelectric disk 50 is positioned inside the screw head and two wires soldered in order to provide the electric path. To protect the piezoelectric element and the wiring the head was molded with epoxy compound. The setup immediately provided two clear echo-reflections from the opposite end of the screw. To increase amplitude of the reflected signals the threaded end of the screw was slightly flattened. In FIG. 3 a typical A-scan is given. The basics of the measurement consist of determining variation of the delay between 1 st and 2 nd reflections. To measure the TOF between the two pulses zero cross-section method is used. The software seeks for the first minimum of both signals and then calculates the time coordinate of next zero cross-section linearly interpolating the signal between two consecutive samples for both first and second echo-pulses and finally estimates TOF as given by the following formula.
TOF = 1 f sampl ( i - j + ( wfm ( i ) wfm ( i ) - wfm ( i + 1 ) - wfm ( j ) wfm ( j ) - wfm ( j + 1 ) ) , ( 1 )
where f sampl is the sampling frequency, wfm(k) is the digitized waveform data, i, j are samples around zero crossing (see FIG. 4 ). Better results are obtained at 1 GHz sampling rate. A real-time measurement provides ±0.2 ns precision, with 32-average mode the precision goes to 0.02 ns. This corresponds approximately to 0.025° C. temperature variation, or 0.6N force variation using for approximation elastic parameters of mild steel. Exact values of these uncertainties are to be calculated after the stress-TOF and temperature-TOF characteristics are studied for the material used in manufacturing the screw. This system results in excellent resolution of the method.
To realize the measurement method a software program may be used. Basic features of the program are transfer of the digitized A-scan from TDS520 to a personal computer, serial port communication, time delay compensation and measurement, and data storage. The outlook of a program window is given in FIG. 5 . Configuration windows for the preload gauge are shown in FIG. 6 .
In another embodiment, depicted in FIG. 8 , wand 90 is designed to transmit and receive acoustic and time of flight data without the need for contact between the wand tip and a transducer located in the head of the screw. In this embodiment, the transducer 50 is positioned within the tip 92 of the wand, near enough to the end to transmit and detect sonic impulses. The wand also incorporates technology for digital analog signals to be transmitted and received in order to carryout the functions identified in the hard-wired control box. The information received and transmitted by the wand may be displayed in a remotely located display mode.
In another embodiment, the ultrasonic transducer may be located within the tool used to tighten the screw. Thus, a screwdriver may be used to tighten the screw and either simultaneously or at the end of the torquing procedure measure the stress within the screw. One end of the screwdriver is formed in a well known latch-type design for attachment to an electronic or manual tightening torque apparatus. At the other end of the screwdriver, the ultrasonic transducer is positioned within the screwdriver end in a position permitting it to transmit and detect sonic impulses. The transducer is electronically connected to the latch-type end by internal circuitry. The transducer is electronically connected to either the electronic or manual tightening torque handpiece by an electronic interface within the handpiece head. The screwdriver is positioned in the screw bore and brought into intimate contact with the screw. Following initiation of the sound impulse, the sound travels through the screw to the end of the screw. In the electronic tightening torque apparatus, the time of flight of the wave propagation through the screw is registered by the transducer in the screw driver, and the information is transferred electronically back to the tightening torque apparatus control boxes or an associated display unit. The elastic properties of the screw, which have been altered by the torquing force used to tighten the screw, are displayed both graphically and digitally at the control box ( 6 ) as the preload.
In the case of the manual tightening torque apparatus, the electronics for initiation of the wave impulse from the screwdriver, and data retrieval and processing are located in a modified handle for the tightening torque apparatus. The registration, recording and computation of the time of flight are performed using micro-processing technology and transferring the information from the electronic port in the manual tightening torque handle ( 2 ) as a digital analog signal to a remote display unit.
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A method and apparatus are provided for determining the preload in a dental implant system. The preload is determined by transmitting a sonic impulse, which is preferably an ultrasonic impulse, at a predetermined frequency to the head of the implant screw through a transducer, which may be incorporated into the head of the screw, the head of a wand which generates the sonic impulse, or the transducer and pulse-generating instrumentation may be incorporated into a torque generating instrument used to tighten the screw. The preload is determined by measuring the delay between the first and second reflections through the preloaded screw to determine a preload value and comparing that value with a pre-established baseline value for the screw, and comparing the difference with a predetermined table of values to determine the preload on the screw.
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This application claims the benefit of U.S. Provisional Application No. 60/413,171, filed Sep. 25, 2002, of which the entire text is incorporated by reference.
FILED OF THE INVENTION
The present invention relates to modified GLP-1 peptides having increased biological potency.
BACKGROUND OF THE INVENTION
Oral ingestion of food leads to the secretion of insulin and insulin counter regulatory hormones in a concerted effort to control blood glucose levels by increasing glucose and free fatty acid uptake by the liver, muscle and adipose tissue, and to reduce gluconeogenesis from the liver.
Insulin secretion is modulated by secretagogue hormones, termed as incretins, which are produced by enteroendocrine cells. Glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) account for almost all of the incretin effect. GIP, but not GLP-1, is ineffective in diabetic subjects. There is thus a great deal of interest in using GLP-1 and its analogues in therapeutic treatments for diabetes [for detailed discussion of GLP-1 physiology, see reviews Kieffer and Habener (1999); Doyle and Egan (2001); Hoist (1999); Perfetti and Merkel (2000); Nauck (1997); Gutniak (1997); Drucker (2001).
A summary of the current knowledge of GLP-1 physiology is provided below. Extensive information and the references to specific aspects are provided in the reviews cited above. GLP-1 is a 30 aa peptide derived from proglucagon, a 160 aa prohormone. Actions of different prohormone convertases in the pancreas and intestine result in the production of glucagons and other ill-defined peptides, whereas cleavage of proglucagon results in the production of GLP-1 and GLP-2 as well as two other peptides. The aa sequence of GLP-1 is 100% homologous in all mammals studied so far, implying a critical physiological role. GLP-1 (7–37) OH is C-terminally truncated and amidated to form GLP-1 (7–36) NH 2 . The biological effects and metabolic turnover of the free acid GLP-1 (7–37) OH, and the amide, GLP-1 (7–36) NH2, are indistinguishable. By convention, the numbering of the amino acids is based on the processed GLP-1 (1–37) OH from proglucagon. The biologically active GLP-1 is the result of further processing: GLP-1 (7–36) NH2. Thus the first amino acid of GLP-1 (7–37) OH or GLP-1 (7–36)NH2 is His7.
In the gastrointestinal tract, GLP-1 is produced by L-cells of intestinal, colonic and rectal mucosa, in response to stimulation by intraluminal glucose. The plasma half-life of active GLP-1 is <5 minutes, and its metabolic clearance rate is around 12–13 minutes (Holst, 1994). The major protease involved in the metabolism of GLP-1 is dipeptidyl peptidase (DPP) IV (CD26) which cleaves the N-terminal His-Ala dipeptide, thus producing metabolites, GLP-1 (9–37) OH or GLP-1 (9–36) NH 2 which are variously described as inactive, weak agonist or antagonists of GLP-1 receptor. GLP-1 receptor (GLP-1R) is a G protein coupled receptor of 463 aa and is localized in pancreatic beta cells, in the lungs and to a lesser extent in the brain, adipose tissue and kidneys. The stimulation of GLP-1R by GLP-1 (7–37) OH or GLP-1 (7–36)NH 2 results in adenylate cyclase activation, cAMP synthesis, membrane depolarization, rise in intracellular calcium and increase in glucose-induced insulin secretion (Holz et al., 1995).
GLP-1 is the most potent insulin secretagogue that is secreted from the intestinal mucosa in response to food intake. Fasting levels of immunoreactive GLP-1 in humans is about 5–10 pmol/L and rises to 25 pmol/L post-prandially (Perfetti and Merkel, 2000 vide supra). The profound incretin effect of GLP-1 is underscored by the fact that GLP-1R knockout mice are glucose-intolerant (Scrocchi et al.,). The incretin response of iv infused GLP-1 is preserved in diabetic subjects, though the incretin response to oral glucose in these patients is compro mised. GLP-1 administration by infusion or sc injections controls fasting glucose levels in diabetic patients, and maintains the glucose threshold for insulin secretion (Gutniak et al. 1992; Nauck et al., 1986; Nauck et al., 1993). GLP-1 has shown tremendous potential as a therapeutic agent capable of augmenting insulin secretion in a physiological manner, while avoiding hypoglycemia associated with sulfonylurea drugs.
Other important effects of GLP-1 on glucose homeostasis are suppression of glucagon secretion and inhibition of gastric motility (Tolessa et al., 1998). GLP-1 inhibitory actions on alpha cells of the pancreas leads to decreases in hepatic glucose production via reduction in gluconeogenesis and glycogenolysis (D'Alessio et al., 1997). This antiglucagon effect of GLP-1 is preserved in diabetic patients.
The so-called ileal brake effect of GLP-1, in which gastric motility and gastric secretion are inhibited, is effected via vagal efferent receptors or by direct action on intestinal smooth muscle. Reduction of gastric acid secretion by GLP-1 contributes to a lag phase in nutrient availability, thus obviating the need for rapid insulin response. In summary, the gastrointestinal effects of GLP-1 contribute significantly to delayed glucose and fatty acid absorption and modulate insulin secretion and glucose homeostasis.
GLP-1 has also been shown to induce beta cell specific genes, such as GLUT-1 transporter, insulin receptor (via the interaction of PDX-1 with insulin promoter), and hexokinase-1. Thus GLP-1 could potentially reverse glucose intolerance normally associated with aging, as demonstrated by rodent experiments (Perfetti and Merkel. 2000. vide supra). In addition, GLP-1 may contribute to beta cell neogenesis and increase beta cell mass, in addition to restoring beta cell function (Wang et al., 1997; Xu et al., 1999).
Central effects of GLP-1 include increases in satiety coupled with decreases in food intake, effected via the action of hypothalamic GLP-1R. A 48 hour continuous sc infusion of GLP-1 in type II diabetic subjects, decreased hunger and food intake and increased satiety (Toft-Nielsen et al., 1999). These anorectic effects were absent in GLP-1R knock out mice (Scrocchi et al., 1996 vide supra).
In summary, the diverse roles played by GLP-1 in maintaining metabolic homeostasis, makes it an ideal drug candidate for treating diabetes, obesity and metabolic syndrome.
Stability of GLP-1 in Circulation
GLP-1 released from the L-cells of the intestine, in response to food, enters portal circulation. It is rapidly cleaved by DPP IV (CD26) to release GLP-1 (9–37) or GLP-1 (9–36) amide, both of which are less active at GLP-1R. According to some reports, they may act as antagonists of GLP-1R and GLP-1 effects on gastrointestinal motility. The half-life of circulating GLP-1 was found to be about 4 minutes (Kreymann et al., 1987). Dipeptidyl-peptidase IV (DPP IV, EC 3.4.14.5, CD26), designated CD26, is an extracellular membrane-bound enzyme, expressed on the surface of several cell types, in particular CD4 + T-cells, as well as on kidney, placenta, blood plasma, liver, and intestinal cells. On T-cells, DPP IV has been shown to be identical to the antigen CD26. CD26 is expressed on a fraction of resting T cells at low density, but is strongly up-regulated following T-cell activation (Gorrell et al., 2001). Recent results indicate that CD26 is a multifunctional molecule that may have an important functional role in T-cells and in overall immune system modulation. CD26 is associated with other receptors of immunological significance found on the cell surface, such as the protein tyrosine phosphatase CD45 and adenosine deaminase (ADA). DPP IV exerts a negative regulation of glucose disposal by degrading GLP-1 and GIP, thus lowering the incretin effect on beta cells of the pancreas.
DPP IV-resistant Analogues of GLP-1
DPP IV cleaves the Ala-Asp bond of the major circulating form of human GLP-1 (human GLP-1 (7–36) NH2: His-Ala-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Val-Ser-Ser-Tyr-Leu-Glu-Gly-Gln -Ala-Ala-Lys-Glu-Phe-lle-Ala-Trp-Leu-Val-Lys-Gly-Arg-NH2) (SEQ ID NO:1), releasing an N-terminal dipeptide.
Substitution of Ala with Gly (Deacon et al., 1998; Burcelin et al., 1999), Leu, D-Ala and other amino acids, was shown to protect GLP-1 from DPP IV degradation and potentiates its in-vitro and in-vivo insulinotropic actions (Xiao et al., 2001).
Deletion of the amino-terminal histidine, or of the NH2 group of His7, decreased receptor affinity and potency of the analogue (Adelhorst et al., 1994; Xiao et al. 2001 vide supra; Siegel et al., 1999).
U.S. Pat. No. 5,545,618 teaches that N-terminal modifications using alkyl and acyl modifications also produced DPP IV resistant analogues. More specifically, His7 substitution by N-alkylated (C 1 – 6 ) or N-acylated (C 1 – 6 ) L-/D-amino acids resulted in analogues possessing DPP IV-resistance. However, the examples given in this patent only cover acetyl and isopropyl groups.
Covalent coupling of unsaturated organic acids, such as trans-3-hexenoic acid, also produces DPP IV-resistant GLP-1 analogs that potently reduce hyperglycemia in oral glucose tolerance tests in mice (Xiao et al. 2001 vide supra). Furthermore, His7 can be replaced by α-substituted carboxylic acids, one of the substituents being a 5- or 6-membered ring structure (e.g. imidazole), in order to confer DPP IV resistance (WO 99/43707). Insertion of 6-aminohexanoic acid (AHA) after His7 was shown to confer DPP IV resistance, while retaining receptor affinity and insulinotropic efficacy in vivo (Doyle et al., 2001).
Numerous GLP-1 analogs demonstrating insulinotropic action are known in the art. These variants and analogs include, for example, GLP-1(7–36), Gln9-GLP-1(7–37), D-Gln9-GLP-1(7–37), acetyl-Lys9-GLP-1(7–37), Thr16-Lys18-GLP-1(7–37), and Lys18-GLP-1(7–37). Derivatives of GLP-1 include, for example, acid addition salts, carboxylate salts, lower alkyl esters, and amides (WO 91/11457 (1991); EP 0 733,644 (1996); and U.S. Pat. No. 5,512,549 (1996)). It has also been demonstrated that the N-terminal histidine residue (His7) is very important to the insulinotropic activity of GLP-1 (Suzuki et al., 1988).
Modification of His7 by alkyl or acyl (C1–6) groups, and replacement of His with functionally-equivalent C5–6 ring structures appears to confer DPP IV resistance. However, current information does not divulge if all covalent modifications of His7 also retain GLP-1 function in vitro and in vivo.
There thus remains a need to develop modified GLP-1 peptides having increased biological potency.
The present invention seeks to meet these and other needs.
The present description refers to a number of documents, the content of which is herein incorporated by reference in their entirety.
SUMMARY OF THE INVENTION
The present invention relates to a GLP-1 peptide having the following formula, or a pharmaceutically acceptable salt thereof:
X-His-Ala-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Val-Ser-Ser-Tyr-Leu-Glu-Gly-GIn-Ala-Ala-Lys-Glu-Phe-lle-Ala-Trp-Leu-val-Lys-Gly-Arg-Y (SEQ ID NO. 1)
wherein X is a rigidifying hydrophobic moiety selected from the group consisting of:
i. C 1 –C 10 alkenoic acid, with the proviso that the alkenoic acid is not trans-3-hexenoic acid; wherein the alkenoic acid can be substituted by at least one substituent selected from the group consisting of straight or branched C 1 –C 6 alkyl, C 3 –C 6 cycloalkyl, aryl and substituted aryl;
ii. C 1 –C 10 alkynoic acid;
iii. C 3 –C 10 cycloalkanoic acid or heterocycloalkanoic acid; wherein the heterocycloalkanoic acid includes a heteroatom selected from the group consisting of O, S and N;
iV. C 5 –C 14 arylcarboxylic or arylalkanoic acid, wherein the arylcarboxylic or arylalkanoic acid can be substituted by at least one substituent selected from the group consisting of lower alkyl, lower alkoxy, lower alkylthio, halo, hydroxy, trifluoromethyl, amino, —NH(lower alkyl), —N(lower alkyl) 2 , di- and tri-substituted phenyl, 1-naphthyl, and 2-naphthyl; wherein the di- and tri-substituted phenyl, 1-naphthyl, and 2-naphthyl are substituted with a substituent selected from the group consisting of methyl, methoxy, methylthio, halo, hydroxy, and amino;
v. C5–C14 heteroarylcarboxylic or heteroarylalkanoic acid, wherein the heteroarylcarboxylic or heteroarylalkanoic acid includes a heteroatom selected from the group consisting of O, S and N, and wherein the heteroarylcarboxylic or heteroarylalkanoic group can be substituted by at least one substituent selected from the group consisting of lower alkyl, lower alkoxy, lower alkylthio, halo, hydroxy, trifluoromethyl, amino, —NH(lower alkyl), or —N(lower alkyl) 2 , di- and tri-substituted phenyl, 1-naphthyl, and 2-naphthyl; wherein the di- and tri-substituted phenyl, 1-naphthyl, and 2-naphthyl are substituted with a substituent selected from the group consisting of methyl, methoxy, methylthio, halo, hydroxy, and amino; and
Y is selected from the group consisting of OH, NH2 and Gly-OH.
In one particular embodiment, the present invention relates to a peptide wherein X is selected from the group consisting of
In a second particular embodiment, the present invention relates to a peptide wherein X is selected from the group consisting of 3-aminophenyl acetyl, 3-methoxyphenyl acetyl, salicyl, (1R, 2R) 2-ethylcyclopropyl acetyl, and (1S, 2S) 2-ethylcyclopropyl acetyl.
The present invention relates to a composition comprising a therapeutically effective amount of a peptide of the present invention, or a pharmaceutically acceptable salt thereof, in association with at least one constituent selected from the group consisting of pharmaceutically acceptable carrier, diluent and excipient.
In a particular embodiment, the present invention relates to a composition, wherein the therapeutically effective amount is comprised between about 1 mcg and about 10 mg.
The present invention relates to a composition comprising a prophylactically effective amount of a peptide of the present invention, or a pharmaceutically acceptable salt thereof, in association with at least one constituent selected from the group consisting of pharmaceutically acceptable carrier, diluent and excipient.
The present invention further relates to a method of treating a disease or condition associated with a disorder of glucose metabolism. The invention, in yet another embodiment relates to a prevention (e.q. prophylaxis) of a disease or condition associated with glucose metabolism. Non-limiting examples of glucose disorder include: diabetes mellitus of Type I or Type II, or insulin resistance, weight disorders and diseases or conditions associated thereto, wherein such weight disorders or associated conditions include obesity, overweight-associated conditions, satiety deregulation, reduced plasma insulin levels, increased blood glucose levels, or reduced pancreatic beta cell mass.
In one embodiment, the present invention relates to a method for treating diabetes mellitus of Type I or Type II, comprising the step of administering to a subject in need of such treatment a therapeutically effective amount of the peptide of the present invention, or a pharmaceutically acceptable salt thereof.
In a second embodiment, the present invention relates to a method for treating insulin resistance, comprising the step of administering to a subject in need of such treatment a therapeutically effective amount of the peptide of the present invention, or a pharmaceutically acceptable salt thereof.
In a third embodiment, the present invention relates to a method for weight lowering of a subject, comprising the step of administering an effective amount of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, to the subject.
In a fourth embodiment, the present invention relates to a method for reducing satiety of a subject, comprising the step of administering a therapeutically effective amount of the peptide of the present invention, or a pharmaceutically acceptable salt thereof to the subject in need thereof.
In a fifth embodiment, the present invention relates to a method for post-prandially increasing plasma insulin levels in a subject, comprising the step of administering a therapeutically effective amount of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, to the subject.
In a sixth embodiment, the present invention relates to a method for reducing fasting blood glucose levels in a subject, comprising the step of administering a therapeutically effective amount of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, to the subject.
In a seventy embodiment, the present invention relates to a method for increasing pancreatic beta cell mass in a subject, comprising the step of administering a therapeutically effective amount of the peptide of the present invention, or a pharmaceutically acceptable salt thereof to the subject.
In a particular embodiment, the present invention relates to a method, wherein the peptide, or a pharmaceutically acceptable salt thereof, is administered to a subject through an administration route selected from the group consisting of subcutaneous, intravenous, transdermal, oral, bucal, and intranasal.
In a particular embodiment, the present invention relates to a method, wherein the subject is a human.
The present invention further relates to a use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for treating diabetes mellitus of Type I or Type II in a subject.
The present invention further relates to a use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for treating insulin resistance in a subject.
The present invention further relates to a use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for lowering weight of a subject.
The present invention further relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for reducing satiety of a subject.
The present invention further relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for post-prandially increasing plasma insulin levels in a subject.
The present invention further relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for reducing fasting blood glucose level in a subject.
The present invention further relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for increasing pancreatic beta cell mass in a subject.
The present invention further relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for treating diabetes mellitus of Type I or Type II in a subject.
The present invention further relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for treating insulin resistance in a subject.
The present invention further relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for lowering weight of a subject.
The present invention further relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for increasing satiety of a subject.
The present invention further relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for post-prandially increasing plasma insulin levels in a subject.
The present invention further relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for reducing fasting blood glucose levels in a subject.
Finally, the present invention relates to the use of the peptide of the present invention, or a pharmaceutically acceptable salt thereof, for the preparation of a medicament for increasing pancreatic beta cell mass in a subject.
Further scope and applicability will become apparent from the detailed description given hereinafter. It should be understood however, that this detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the invention, reference will now be made to the accompanying drawings, showing by way of illustration a preferred embodiment thereof, and in which:
FIG. 1 illustrates glucose disposal produced by GLP-1 analogues using the Oral glucose tolerance test (OGTT), in CD-1 normal female mice (6 wk. Charles River, Montreal, Canada);
FIG. 2 illustrates glucose clearance and plasma insulin levels produced by ip injection of compound 7 (1 and 10 μg/mouse);
FIG. 3 illustrates glucose clearance in db/db mice (female; 8–10 wks; C57BLKS/J-M+/+Lepr db ; Jackson laboratories, Bar Harbor, Mich.) in response to GLP-1 analogues;
FIG. 4 illustrates plasma insulin levels using the Intraperitoneal Glucose Tolerance Test (IPGTT), in rats injected iv with GLP-1 analogues;
FIG. 5 illustrates the average insulinogenic index of GLP-1 analogues;
FIG. 6 illustrates glucose levels, following 30 minutes of feeding, in overnight fasted C57BL/ks db/db mice (Harlan) injected subcutaneously with GLP-1 and compounds 5, 8, and 17 (500 μg/kg; n=6);
FIG. 7 illustrates the effect of GLP-1, 16, or 17 (300 μg/rkg subcutaneous; n=6) on glucose levels during a hyperglycemic clamp in Sprague-Dawley rats; and
FIG. 8 illustrates a DPP IV degradation assay.
Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of preferred embodiments with reference to the accompanying drawing(s), which is exemplary and should not be interpreted as limiting the scope of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Definitions:
As used herein, the term “subject” is intended to mean a mammal selected from the group consisting of human, porcine, bovine, caprine, ovine, feline, canine and equine.
As used herein, the term “GLP-1 analogues” is intended to mean analogues which are biologically-active GLP-1 peptides that include GLP-1 (7–37)OH, GLP-1 (7–36)NH 2 and their derivatives; these derivatives include peptides that contain amino acid substitutions, made with the intention of improving solubility (replacement of hydrophobic amino acids with hydrophilic amino acids, PEGylation of terminal carboxyl groups or the ε-amino group of lysine), conferring resistance to oxidation (substitution of Met, Trp, Gin, Asn), increasing biological potency in in vitro and in vivo assays (one or more amino acid substitutions at positions 11, 12, 16, 22, 23, 24, 25, 27, 30, 33, 34, 35, 36, or 37, but not those at 8), or increasing half-life in circulation (acyl (C 12 –C 18 ) modifications of the ε-amino group of lysine).
As used herein, the term “rigidifying hydrophobic moiety” is intended to mean a conformationally rigid moiety, which has a limited number of spatial orientations due to the presence of one or more rigidifying elements in its backbone such as, a double bond, a triple bond, or a saturated or unsaturated ring, which have little or no conformational mobility. As a result, the number of conformers or rotational isomers is reduced when compared to the corresponding straight, or unsubstituted and saturated aliphatic chain. These rigidifying hydrophobic moieties are divided into the following groups:
Group 1: Straight or branched alkenoic acid derivatives, e.g.:
Group 2: Straight or branched alkynoic acid derivatives, e.g.:
Group 3: Cycloalkanoic or heterocycloalkanoic acid derivatives, e.g.:
Group 4: Aryl, arylalkanoic, heteroaryl or heteroarylalkanoic acid derivatives, e.g.:
As used herein, the term “unit dosage form” refers to physically discrete units, suitable as unitary dosages for human subjects and other mammals; each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with one/or more suitable pharmaceutical excipients.
As used herein, the term “aryl” refers to phenyl, 1-naphthyl, and 2-naphthyl.
As used herein, the term “substituted aryl” refers to phenyl, 1-naphthyl, and 2-naphthyl having a substituent selected from lower alkyl, lower alkoxy, lower alkylthio, halo, hydroxy, trifluoromethyl, amino, —NH(lower alkyl), —N(lower alkyl) 2 , as well as di- and tri-substituted phenyl, 1-naphthyl, or 2-naphthyl, the di- and tri-substituted phenyl, 1-naphthyl, and 2-naphthyl comprising a substituent selected from the group consisting of methyl, methoxy, methylthio, halo, hydroxy, and amino.
The present invention also includes salt forms of GLP-1 analogs. A GLP-1 analog of the present invention may be sufficiently acidic or sufficiently basic to react with any of a number of organic and inorganic bases, and organic and inorganic acids, to form a salt. Acids commonly employed to form acid addition salts are inorganic acids such as hydrochloric acid, hydrobromic acid, hydroibdic acid, sulfuric acid, phosphoric acid, and the like, and organic acids such as p-toluenesulfonic acid, methanesulfonic acid, oxalic acid, p-bromophenyl-sulfonic acid, carbonic acid, succinic acid, citric acid, benzoic acid, acetic acid, and the like. Examples of such salts include sulfate, pyrosulfate, bisulfate, sulfite, bisulfite, phosphate, monohydrogenphosphate, dihydrogenphosphate, metaphosphate, pyrophosphate, chloride, bromide, iodide, acetate, propionate, decanoate, caprylate, acrylate, formate, isobutyrate, caproate, heptanoate, propiolate, oxalate, malonate, succinate, suberate, sebacate, fumarate, maleate, butyne-1,4-dioate, hexyne-1,6-dioate, benzoate, chlorobenzoate, methylbenzoate, dinitrobenzoate, hydroxybenzoate, methoxybenzoate, phthalate, sulfonate, xylenesulfonate, phenylacetate, phenylpropionate, phenylbutyrate, citrate, lactate, gamma-hydroxybutyrate, glycolate, tartrate, methanesulfonate, propanesulfonate, naphthalene-1-sulfonate, naphthalene-2-sulfonate, mandelate, and the like. Preferred acid addition salts are those formed with mineral acids such as hydrochloric acid and hydrobromic acid. A more preferred acid addition salt is formed with hydrochloric acid.
Base addition salts include those derived from inorganic bases, such as ammonium or alkali or alkaline earth metal hydroxides, carbonates, bicarbonates, and the like. Such bases, useful in preparing the salts of this invention, thus include sodium hydroxide, potassium hydroxide, ammonium hydroxide, potassium carbonate, and the like. Salt forms of GLP-1 analogs are particularly preferred. Of course, when the compounds of the present invention are used for therapeutic purposes, the compounds may also be in the form of a salt, however, the salt must be a pharmaceutically acceptable salt.
The present invention relates to a GLP-1 peptide, modified by the covalent attachment of a hydrophobic group to the N-terminus, thus resulting in protease resistance, more specifically DPP IV resistance.
Given the sequence information as disclosed herein, and the state of the art in solid phase protein synthesis, GLP-1 analogs can be obtained via chemical synthesis. The principles of solid phase chemical synthesis of polypeptides are well known in the art (Dugas and Penney, 1981; Merrifield, 1962; Stewart and Young, 1969).
Examples for synthesizing the peptides of the present invention are provided below.
The present invention also relates to pharmaceutical compositions comprising a GLP-1 analog of the present invention, in combination with a pharmaceutically acceptable carrier, diluent, or excipient. Such pharmaceutical compositions are prepared in a manner well known in the pharmaceutical art, and are administered individually or in combination with other therapeutic agents, preferably via parenteral routes. Especially preferred routes of administration include intramuscular and subcutaneous administration.
Parenteral daily dosages, preferably a single daily dose, are typically in the range of from about 1 mcg/kg to about 100 mcg/kg of body weight, although lower or higher dosages may be administered. The required dosage will depend upon the severity of the condition of the patient and upon such criteria as the patient's height, weight, sex, age, and medical history.
In making the compositions of the present invention, the active ingredient, which comprises at least one peptide of the present invention, is usually mixed or diluted with an excipient. When an excipient is used as a diluent, it may be a solid, semi-solid, or liquid material which acts as a vehicle, carrier, or medium for the active ingredient.
Examples of suitable excipients include, but are not limited to lactose, dextrose, sucrose, trehalose, sorbitol, mannitol, starches, gum acacia, calcium silicate, microcrystalline cellulose, polyvinylpyrrolidone, cellulose, water, syrup, and methyl cellulose. The formulations can additionally include lubricating agents such, but not limited to, talc, magnesium stearate and mineral oil. The formulations may further include wetting agents, emulsifying and suspending agents, preserving agents such as methyl- and propylhydroxybenzoates, sweetening agents or flavoring agents. The compositions of the invention can be formulated so as to provide quick, sustained or delayed release of the active ingredient following administration to the patient, by employing formulation procedures well known in the art.
The compositions of the present invention are preferably formulated in unit dosage form, with each dosage normally containing from about 1 mcg to about 10 mg of the active ingredient.
Additional pharmaceutical methods may be employed to control the duration of action. Controlled release preparations may be achieved by the use of polymers to complex or absorb a peptide of the present invention. The controlled delivery of the active ingredient (peptide) may be exercised by selecting appropriate macromolecules (for example, polyesters, polyamino acids, polyvinylpyrrolidone, ethylene vinylacetate copolymers, methylcellulose, carboxymethylcellulose, and protamine sulfate), the concentration of the macromolecules as well as the methods of incorporation. Such teachings are disclosed in Remington's Pharmaceutical Sciences (1980).
Another possible method to control the duration of action by controlled release preparations, is to incorporate a peptide of the present invention into particles of a polymeric material such as polyesters, polyamino acids, hydrogels, poly (lactic acid) or ethylene vinylacetate copolymers.
The present invention is illustrated in further detail by the following non-limiting examples.
EXAMPLE 1
Solid Phase Synthesis of GLP-1 (7–37)COOH or GLP-1 (7–37)CONH 2 and Coupling of Rigid Hydrophobic Pharmacophores
The analogues of the present invention are made by solid phase peptide synthesis, using fluorenylmethoxycarbonyl-protected L-amino acids (Peptide synthesis protocols, 1994). Completion of coupling was monitored by the Kaiser color test. The organic acids disclosed in Table 1 were coupled by the same method as used for coupling amino acids. The crude peptides were further purified by preparative HPLC on Vydac C 18 -columns using an acetonitrile gradient in 0.1% TFA. The peptides were vacuum-dried to remove acetonitrile, and lyophilized from 0.1% TFA. Purity was assessed by analytical HPLC and masses were determined by MALDI-TOF mass spectroscopy using a Voyager Biospectrometry Workstation (Perspective Systems). The peptides were prepared as TFA salts and dissolved in saline for administration to animals.
TABLE 1
R repres nts HN-[His7] GLP-1 (7–37)COOH OR HN-[His7] GLP-1 (7–
36)CONH 2 .
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
EXAMPLE 2
Effects of GLP-1, 5, 8, 16 and 17 on cAMP Production in RINm5F Cells
RINm5F cells (ATCC # CRL-2058) were grown to confluence and used 4 days following confluency. Aqueous stock solutions (1 mM) of GLP-1, 5, 8, 16, and 17, also containing 0.1% BSA, were made prior to the assay. The numbers refer to compounds listed in Table 2. Cells were pre-incubated with 100 μl RPMI containing 0.5 mM IBMX for 10 minutes at 37° C. Diluted (10 −5 to 10 −11 M) peptides (100 μl) were added to the wells and incubated for 40 minutes. At the end of the incubation period, the supernatant was collected and assayed for cAMP using a radioimmunoassay kit (Diagnostic Product Corporation). Maximal responses (pmol/mg protein) and IC 50 (nM) values were evaluated from the dose-response curves and data presented in Table 3.
TABLE 2
GLP-1 analogues containing rigid hydrophobic pharmacophores.
Compound
Description of GLP-1 peptide
Wild type
GLP-1 (7–37) OH
1
[H7] diphenylacetic acid GLP-1 (7–37) COOH
2
[H7] O-tolylacetic acid GLP-1 (7–37) COOH
3
[H7] α-phenyl O-toluic acid GLP-1 (7–37) COOH
4
[H7] (+, −) cis 2-ethylcyclopropyl acetic acid
GLP-1 (7–37) COOH
5
[H7] 3-aminophenyl acetic acid GLP-1 (7–37) COOH
6
[H7] 2-ethoxybenzoic acid GLP-1 (7–37) COOH
7
[H7] 3-methoxyphenyl acetic acid GLP-1 (7–37) COOH
8
[H7] Salicylic acid GLP-1 (7–37) COOH
9
[H7] n-phenyl anthranilic acid GLP-1 (7–37) COOH
10
[H7] 3-(phenylthio)acrylic acid GLP-1 (7–37) COOH
11
[H7] 2,6-difluorophenyl acetic acid GLP-1 (7–37) COOH
12
[H7] 2,3,4,5,6-pentafluorophenyl acetic acid GLP-1
(7–37) COOH
13
[H7] 3-hydroxy phenyl acetic acid GLP-1 (7–37) COOH
14
[H7] (1R, 2R) 2-ethylcyclopropyl acetic acid GLP-1
(7–37) COOH
15
[H7] (1S, 2S) 2-ethylcyclopropyl acetic acid GLP-1
(7–37) COOH
16
[H7] 3-aminophenyl acetic acid GLP-1 (7–36) CONH 2
17
[H7] Salicylic acid GLP-1 (7–37) CONH 2
TABLE 3
Effects of GLP-1, 5, 8, 16 and 17 on
cAMP production in RINm5F cells.
Maximal
IC 50
Response
Agent
(nM)
(pmol/mg protein)
n
GLP-1
6.4 ± 3.8
17.6 ± 5.1
10
5
8.7 ± 9.8
20.0 ± 6.9
4
8
13.9 ± 15.6
25.1 ± 11.9
5
16
10.2 ± 7.7
13.8 ± 3.6
5
17
13.2 ± 5.2
21.9 ± 2.1
6
Mean ± SD;
n = number of experiments done in duplicate.
EXAMPLE 3
Testing the Biological Activity of GLP-1 Analogues Using the Oral Glucose Tolerance Test
GLP-1 peptides (1, 5 and 10 μg per mouse) were injected i.p. into overnight fasted CD-1 normal female mice (6 wk. Charles River, Montreal, Canada) 5 minutes prior to an oral glucose challenge (40% glucose solution); glucose (1 g/kg body weight) was administered by oral gavage at t=0 minutes, and blood samples were drawn by tail vein excision; blood glucose levels (mmol/L) were determined at t=0, 10, 20, 30, 60, 90 and 120 minutes using a One-Touch glucometer (Lifescan Canada, Burnaby, BC, Canada). The area under the curve (AUC Glucose [mmol/L*120 min]) was calculated using the trapezoidal method (N=3–4 animals per group). The results are shown in FIG. 1 . The horizontal line represents vehicle control (n=50). There was a dose dependent improvement in glucose clearance in all cases. At the highest dose tested, compounds 5, 7, 8, 14, and 15 were clearly superior in efficacy to an identical same dose of GLP-1 (7–37)COOH.
EXAMPLE 4
Dose-Effect of Compound 7 on Glucose and Insulin Levels in Normal CD-1 Female Mice
An OGTT was done as described above. Plasma insulin levels were determined using a commercial RIA kit (Linco Research). The results are shown in FIG. 2 . Compound 7 was administered ip and blood glucose (mmol/L) and plasma insulin levels (ng/ml) by RIA (Linco Research) were measured. It was found that there was no effect on glucose disposal using 1 μg doses. However, 10 μg of compound 7 significantly improved glucose clearance in CD-1 mice. Correspondingly, the plasma insulin levels were higher at 15 and 60 minutes following treatment with 10 μg of compound 7.
EXAMPLE 5
Effect of GLP-1 Analogues in the OGTT in Diabetic Mice (db/db)
A genetic mutation at the leptin receptor locus renders this strain of mice diabetic, and has been used as a useful model for diabetes. An OGTT was conducted as described in Example 3. Peptides were injected intra-parentally (ip) at 5 μG/mouse doses. The results are shown in FIG. 3 (peptide administration, OGTT and glucose measurements were performed as described in the legend for FIG. 1 ). Three peptides, 7, 8 and 15 performed better than GLP-1 in accelerating glucose disposal in this model.
EXAMPLE 6
Effect of GLP-1 Analogues on Plasma Insulin Levels in the Intraperitoneal Glucose Tolerance Test (IPGTT) Using Sprague-Dawley rats
Sprague-Dawley rats (300–350 g) were fasted overnight, and injected with 1 g/kg glucose (2 ml) (over 15–20 seconds), and blood glucose levels were determined at different times during a period of 3 hours using a portable glucometer. The drugs (10 μg/rat) were dissolved in saline and injected into the femoral vein 5 minutes before the injection of glucose. Thus 0 time represents blood glucose and insulin levels after drug administration but before glucose injection. Plasma insulin levels were determined using a radioimmunoassay kit (Linco). Glucose and insulin levels are shown in mmol/L and ng/ml respectively. The insulinogenic index was calculated as delta insulin (pM)/delta glucose (mM). The results are shown in FIG. 4 . In all groups of rats, the basal insulin levels were not affected by GLP-1 analogues alone. Glucose injections produced rapid responses in plasma insulin levels and the values obtained at 0, 30, 60, 90 minutes following glucose administration are shown in the bar graph. Cross bars are shown to indicate the relative levels compared to saline (n=8) and GLP-1 (n=4) injections. Based on these results, 5 (n=4) and 15 (n=4) produced higher average insulin levels than GLP-1, whereas 7 (n=4) was similar to GLP-1 in response. The order of efficacy in these experiments was found to be 15=5>7=GLP-1>8=vehicle.
EXAMPLE 7
Fed C57BL/ks db/db Mice
C57BL/ks db/db mice were fasted overnight and then allowed free access to food for a period of 30 minutes. Immediately following feeding, sc injections of vehicle, GLP-1, 5, 8, or 17 (500 μg/kg) were given, and glucose levels measured for 2 hours in blood drawn from a tail cut. Blood glucose levels (mmol/L) were determined using an AccuCheck compact glucometer (Roche, Germany). The obtained data are presented in FIG. 6 as Mean±SEM.
EXAMPLE 8
Glucose Clamp in Sprague-Dawley Rats
Rats were fasted overnight, anesthetized (isoflurane 2%) and catheterized to receive intravenous glucose at a rate and concentration such as to maintain a glycemia between 16 and 18 mmol/L blood glucose. After reaching a stable glucose level and stabilizing it for a period of 1 hour, subcutaneous injections of vehicle, GLP-1, 16, or 17 (300 pg/kg) were administered and glucose levels measured for an additional 2 hours. Blood samples were drawn from interdigital punctures and blood glucose levels (mmol/L) monitored by an AccuCheck compact glucometer (Roche, Germany). The obtained data are presented in FIG. 7 .
EXAMPLE 9
DPPIV Resistance Assay
Aliquots (100 μg) of GLP-1 (7–37) or 5 were incubated at room temperature (22–24° C.) in duplicates with 50 mU of DPP IV (Sigma-Aldrich), in 20 mM Tris-HCL buffer, pH 8.0. The reaction mixture was sampled at different times and directly analysed by RP-HPLC using Vydac C 18 columns. The peak areas were determined by Chemstation rev. A.05.01 data analysis software (Agilent Technologies). The observed data are expressed as the % remaining area in comparison to the undigested controls and are shown in FIG. 8 .
Although the present invention has been described hereinabove by way of preferred embodiments thereof, it can be modified without departing from the spirit and nature of the subject invention as defined in the appended claims.
REFERENCES
The following references, to the extent that they provide exemplary procedural or other details supplementary to those set forth herein, are specifically incorporated herein by reference.
U.S. Pat. No. 5,512,549 U.S. Pat. No. 5,545,618 Adelhorst et al., J. Biol. Chem., 269(9):6275–6278, 1994. Burcelin et al., Metabolism, 48(2):252–258, 1999. D'Alessio et al., Diabetes, 46(Suppl 1):29A, 1997. Deacon et al., Diabetologia, 41:271–278, 1998. Doyle and Egan, Recent Prog. Horm. Res., 56:377–399, 2001. Doyle et al., Endocrinol., 142(10):44624468, 2001. Drucker, Endocrinol., 142(2):521–527, 2001. Dugas and Penney, In: Bioorganic Chemistry , Springer-Verlag, N.Y., 54–92, 1981. EP 0 733,644 Gorrell et al., Scand. J. Immunol., 54(3):249–264, 2001. Gutniak et al., New Engl. J. Med., 326:1316–1322, 1992. Gutniak, Intl. Diabet. Monitor, 9(2):1–12, 1997. Holst, Gastroenterology, 107:1848–1855, 1994. Holst, Trends Endocrinol. Metab., 10(6):229–235, 1999. Holz et al., J. Biol. Chem., 270:17749–17757, 1995. Kieffer and Habener, Endocrine, 20(6):876–913, 1999. Kreymann et al., Lancet., 2(8571):1300–1304, 1987. Merrifield, Chem. Soc., 85:2149,1962. Nauck et al., Diabetologia, 29:46–52, 1986. Nauck et al., Ibid, 36:741–744, 1993. Nauck, Cur. Opin. Endocrinol. Diabet, 4:291–299,1997. PCT Appin. WO 91/11457 PCT Appln. WO 99/43707 Peptide synthesis protocols: Methods in molecular biology Vol. 35. Pennington and Dunn (Eds), Humana Press, 1994. Perfetti and Merkel, Eur. J. Endocrinol., 143:717–725, 2000. Remington's Pharmaceutical Sciences, 15th ed., 33:624–652, Mack Publishing Company, Easton, Pa., 1980. Scrocchi et al., Nat. Med., 2:1254–1258, 1996. Siegel et al., Reg. Peptides, 79:93–102, 1999. Stewart and Young, In: Solid Phase Peptide Synthesis, 24–66, Freeman, San Francisco, 1969. Suzuki et al., Diabetes Res., 5(Supp. 1):S30, 1988. Toft-Nielsen et al., Diabetes Care, 22:1137–1143. 1999. Tolessa et al., J. Clin. Invest., 102:764–774, 1998. Wang et al., J. Clin. Invest., 99:2883–2889, 1997. Xiao et al., Biochemistry, 40:2860–2869, 2001. Xu et al., Diabetes, 48:2270–2276, 1999.
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The present invention relates to a GLP-1 peptide having the following formula, or a pharmaceutically acceptable salt thereof:
X-His-Ala-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Val-Ser-Ser-Tyr-Leu-Glu-Gly-Gln-Ala-Ala-Lys-Glu-Phe-lle-Ala-Trp-Leu-val-Lys-Gly-Arg-Y (SEQ ID NO. 1)
wherein X is a rigidifying hydrophobic moiety and wherein Y is selected from the group consisting of OH, NH 2 and Gly-OH. Moreover, the present invention relates to pharmaceutical compositions comprising a therapeutically effective amount of a peptide of the present invention, or a pharmaceutically acceptable salt thereof, in association with at least one constituent selected from a pharmaceutically acceptable carrier, diluent, and excipient.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International Application No. PCT/EP2011/000460 filed Feb. 2, 2011, which designated the United States, and claims the benefit under 35 USC §119(a)-(d) of German Application No. 10 2010 006 816.0 filed Feb. 3, 2010.
FIELD OF THE INVENTION
[0002] The invention relates to a hinge for a furniture part and piece of furniture.
BACKGROUND OF THE INVENTION
[0003] In the furniture sector, hinges for the pivotable mounting of furniture parts on a body are known. These hinges may comprise a fastening or hinge part attachable to the body and a hinge part fixable to the movable furniture part. By means of the fastening parts pivotable with respect to one another, furniture parts, such as, a door wing or a flap, can be moved via a joint mechanism provided by the hinge.
[0004] In what are known as double-link or four-joint hinges, for example, two articulated levers or articulated arms are present on the hinge.
SUMMARY OF THE INVENTION
[0005] The object of the present invention is to design abovementioned arrangements compactly with extended functionality. At the same time, a visually advantageous appearance of the hinge is to be implemented.
[0006] The invention proceeds from a hinge for a movable furniture part, in particular door or flap, fastened to a body of a piece of furniture, the hinge having a first fastening part which is attachable to the body and which is connected pivotably via a joint mechanism to a second fastening part attachable to the movable furniture part, the joint mechanism comprising articulated levers mounted via axes of articulation. A first essential aspect of the present invention is that a further pivotably mounted lever is present, which, during a complete as-intended pivoting movement of the hinge, is temporarily coupled to a guide portion on the hinge, the further lever acting upon a damper arrangement of the hinge. The damper arrangement of the hinge serves, in particular, during an as-intended pivoting movement of the hinge, to achieve a damped or braked movement into an end position of the pivoting action executed by the hinge. Consequently, when the hinge is in the state mounted on the piece of furniture, in particular, an undesirably violent slamming shut of the movable furniture part is avoided, in particular an unpleasant slamming-shut noise or damage to the furniture part and to the body.
[0007] The actuation of the damper arrangement takes place, in interaction of the further lever with the guide portion, advantageously always at the same point of the pivoting movement of the furniture part or in an always identical pivoting position of the hinge on the way into an end position of the pivoting movement which is possible by means of the hinge. The interaction of the further lever with the guide portion can be implemented in a highly space-saving way or compactly. In particular, the further lever and the guide portion may be provided in regions which are in any case free in known corresponding hinges. These regions preferably lie inside the hinge and are not visible or are scarcely visible from outside. Consequently, in the arrangement according to the present invention, a desired visual appearance or a preferred external design can be implemented without difficulty.
[0008] A further essential aspect of the present invention is that a further pivotably mounted lever is present, which, during a complete as-intended pivoting movement of the hinge, is temporarily coupled to a guide portion on the hinge, the further lever acting upon an actuator of the hinge. An actuator is to be understood, in general, as meaning an element which converts an input variable into an output variable of a different type in order to bring about a desired action or effect. Actuator principles which may be envisaged are, for example, inductively operating electric motors, hydraulic or pneumatic actuators, cylinders, electrochemical or electromechanical actuators or piezo-actuators.
[0009] In particular, an electric motor can be operated or activated via the interaction of the further lever with the guide portion.
[0010] By means of the actuator or electric motor, for example, a closing and/or opening movement of the movable furniture part can be influenced.
[0011] Also, for example, locking or latching of the movable furniture part via the actuator, in particular, in a closed end position via the actuator may be envisaged.
[0012] Basically, the possibility is not ruled out where a plurality of components, for example a damper arrangement and an actuator, can be acted upon via the interaction of the further lever with the guide portion.
[0013] Even two or more further levers having, in particular, in each case an assigned guide portion may be provided on a hinge.
[0014] By means of the hinge, when the hinge is in the installed state on the piece of furniture, a to-and-fro movement is predetermined in a kinematically defined way, the end positions of which are assigned to a completely closed and completely open position of the furniture part in relation to the body. The coupling of the further lever to the guide portion takes place at a specific point in the pivoting movement and the uncoupling of the further lever from the guide portion takes place during the subsequent return movement. During this interaction, starting from an end point, the further lever and the guide portion are put together after a specific fraction of the overall possible rotational or pivoting movement of the hinge. For example, as a result of the intermeshing of the two elements, their further movement then takes place together or in connection with one another. In this coupling state, the lever acts upon the damper arrangement or the actuator.
[0015] Intermeshing or coupling may take place, for example, with the aid of a capture or threading-in mechanism. For this purpose, the guide portion may have, for example, a slotted-link guide for the further lever. For this purpose, a portion of the further lever is exactly coordinated in its shape with the slotted-link guide.
[0016] The system may also be considered as a type of positive control of the further lever by the guide portion. The further lever remains unmoved in the non-coupled state and is pivoted in the coupling state.
[0017] It is also possible that movement of the guide portion and the further lever, even with respect to one another or contradirectionally, takes place until coupling occurs. During coupling, the movement of one of the two components may be stopped. In the coupled state, the overall system composed of the guide portion and of the further lever moves further on in a defined way, and resulting guidance in the guide portion may correspond to the instantaneous center of the movement of the further lever.
[0018] Preferably, the further lever is received pivotably via an axis separate from the axes of articulation. The further lever can thus be positioned variably or so as to be adapted to conditions of space. The further lever may be present, for example, on a fastening part in the region between two existing axes of articulation.
[0019] Moreover, it is advantageous that the further lever and the guide portion are coordinated with one another in such a way as to cancel a coupling state between the further lever and the guide portion which occurs during an as-intended pivoting movement of the hinge into an end position when the hinge executes a pivoting movement out of the end position. The coupling of the further lever to the guide portion and the maintenance of the coupling state take place via a part or a phase of the overall pivoting movement which is possible by means of the hinge. This phase describes, in particular, a phase before an end point of the pivoting movement is reached, that is to say the coupling point up to the associated end point, without any reversal in direction of movement. Out of this end position, with the direction of movement reversed, the coupling state is maintained until the corresponding coupling point is reached and uncoupling or decoupling takes place. Uncoupling is usually maintained until the other end point is reached. However, further coupling during the pivoting movement into the other end point is not ruled out.
[0020] In the situation mounted on the piece of furniture, during a return movement of the hinge, for example when the movable furniture part is being opened in relation to the body, a decoupled or non-coupled situation of the further lever and of the guide portion is resumed. In this case, the damper arrangement or actuator is brought again into an initial state correspondingly before being acted upon by the lever. During the subsequent renewed closing movement, the damper arrangement or actuator of the hinge is then operated once again.
[0021] It is proposed, further, that the further lever be designed to act upon a portion of a component which is present on the first fastening part attachable to the body. Thus, the damper or actuator can be accommodated on the fastening part attached to the body, this usually being advantageous for structural reasons or for reasons of space.
[0022] Basically, however, the situation is not ruled out where the damper arrangement or actuator is present on the fastening part which is received on the body.
[0023] Advantageously, the guide portion is received between two axes of articulation of the hinge. The guide portion may, in particular, be present advantageously between an axis of articulation fixed in position on a fastening part and an axis of articulation co-moved during the pivoting action. Thus, the guide portion can be accommodated in an especially space-saving way.
[0024] Preferably, the guide portion comprises a guide groove which is designed to be coordinated for temporary coupling to a meshing portion of the further lever. For example, a projecting or raised part, such as a meshing nose on the further lever, can engage into the guide groove and, if appropriate, in the coupling state, be moved along the guide groove. A reversal in shape is not ruled out, whereby the guide portion has a meshing portion which in the coupling state engages into a guide groove on the further lever.
[0025] It is advantageous, further, that the guide portion is present in such a way that the guide portion is co-moved during an as-intended pivoting movement of the hinge. In particular, the guide portion moves whenever the pivoting movement takes place. Thus, the guide portion may be provided, for example, on an articulated lever, for example in one piece with the latter or as an additional part on it.
[0026] Furthermore, it is advantageous that the further lever is mounted pivotably on one of the fastening parts. In particular, the further lever is designed as a two-armed lever. Thus, the further lever can interact at one end with the guide portion and at the other end with the damper arrangement or actuator. The further lever may have a kink or bend, particularly in the region of its axis, as seen in the longitudinal direction.
[0027] It is proposed, further, that the further lever and the damper arrangement be arranged on the same fastening part. Thus, action upon the damper by the lever can take place in the immediate vicinity. The further lever and the actuator can correspondingly be arranged on the same fastening part.
[0028] Furthermore, it is preferable that the hinge is designed as a universal joint hinge. In concrete terms, the universal joint hinge can be designed to be especially stable and for different maximum bridgeable angular ranges of the pivoting movement. The joint mechanism of a universal joint hinge may comprise, in particular, a first and a second universal joint lever and a first and second connecting lever, the first connecting lever being connected via a first joint to the first fastening part and via a second joint to the first universal joint lever which is received on the second fastening part via a third fastening-side universal lever joint, and the second connecting lever being connected via a fourth joint on the second fastening part and via a fifth joint to the second universal joint lever which is received on the first fastening part via a sixth fastening-side universal lever joint, and the two universal joint levers being connected to one another in an articulated way via a universal joint. During the movement of articulation, all the levers can be pivoted simultaneously in each case about an assigned joint of the joints mentioned.
[0029] It is preferable in this case that the guide portion is provided between the universal joint and a fastening-side universal lever joint and, during a pivoting movement capable of being executed by means of the hinge, can be co-moved according to the movement of one of the two universal joint levers.
[0030] In an advantageous modification of the subject of the invention, the hinge is designed as a wide-angle hinge. A wide-angle hinge makes it possible, in the state of use, to have an especially wide opening or pivoting of the movable furniture part in relation to a closed position on the body. Thus, in particular, even greater pivoting angles up to and exceeding 160 degrees of angle can be implemented.
[0031] The invention relates, moreover, to a piece of furniture having a movable furniture part, in particular door or flap, fastened to a body of the piece of furniture, the piece of furniture having a hinge according to one of the abovementioned versions. The advantages already explained above can consequently be implemented on the piece of furniture.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] Further features and advantages of the invention are explained by means of a hinge according to the invention illustrated in the figures.
[0033] FIG. 1 shows a perspective view of a hinge according to the invention in an intermediate position of a pivoting movement executable by means of the hinge;
[0034] FIG. 2 shows a further perspective view of the hinge according to FIG. 1 in an end position;
[0035] FIG. 3 a shows a side view of the arrangement according to FIG. 1 in a section in the longitudinal direction of the hinge;
[0036] FIG. 3 b shows two components of the arrangement according to FIG. 3 a , viewed individually;
[0037] FIG. 4 a shows the hinge according to FIGS. 1 to 3 a in a section in the longitudinal direction in a further end position to the end position according to FIG. 2 ;
[0038] FIG. 4 b shows two components of the arrangement according to FIG. 4 a , viewed individually; and
[0039] FIG. 5 shows an exploded illustration of the hinge in the intermediate position according to FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
[0040] The hinge 1 according to the present invention, shown in the figures, is designed as what is known as a wide-angle or universal joint hinge. The hinge 1 comprises a body hinge part 2 , which is attachable to a body K of a furniture part, and a door wing fastening part or hinge pot or movable furniture part hinge part 3 which is attachable to a furniture part M, such as, for example, a door wing or flap, received movably on the body via the hinge 1 . The body K and the furniture part M are indicated purely diagrammatically in the form of a detail in FIG. 3 a . The hinge parts 2 and 3 can be secured in each case on the inside respectively to the body and to the movable furniture part, in particular, via screws or via quick-action securing means, in particular without a tool. The two hinge parts 2 and 3 are connected to one another pivotably with respect to one another via a joint mechanism by means of four articulated arms 4 to 7 . The articulated arms comprise a first cross arm 4 and a second cross arm 5 and also a first connecting arm 6 and a second connecting arm 7 . In this case, the joint mechanism has seven pivot joints 8 to 14 which are designated below as the first to the sixth joint and as a universal joint. The first joint 8 serves for the pivotable reception of the first connecting arm 6 on the body hinge part 2 , the connecting arm 6 being connected via a second joint 9 to the first cross arm 4 which is received in turn on the furniture part hinge part 3 in an articulated manner via a third joint 10 . Moreover, the second connecting arm 7 is received in an articulated manner on the furniture part hinge part 3 via a fourth joint 11 and is connected in an articulated manner to the second cross arm 5 via a fifth joint 12 . Moreover, the second cross arm 5 is received on the body hinge part 2 in an articulated manner via a sixth joint 13 . Furthermore, the two cross arms 4 , 5 are connected to one another in an articulated manner via a universal joint 14 . All the axes of articulation of the joints 8 to 14 are parallel or perpendicular to the sectional plane of FIGS. 3 a and 4 a.
[0041] In the state mounted on the piece of furniture, the movable furniture part M can consequently be brought via the joint mechanism provided by the hinge 1 out of its position closed with respect to the body K or the end position of the hinge 1 according to FIG. 4 a into a maximum widely pivoted open position of the furniture part or into the end position of the hinge 1 according to FIG. 2 , this corresponding to a maximum pivot angle of more than 160 degrees of angle. The hinge 1 is therefore also designated as a wide-angle hinge.
[0042] As may be gathered from FIG. 5 , the joints 8 to 14 are implemented for their articulated functioning in each case with an axle pin 8 a to 14 a which are received in correspondingly fitting orifices or bores in the components connected to one another.
[0043] Furthermore, it is clear from FIG. 5 that the body hinge part 2 comprises an inner mounting part 15 and a place-on part 16 capable of being placed onto or over the latter. Moreover, the body hinge part 2 comprises, for setting the mounted hinge 1 , adjustment means which comprise setscrew 17 and an adjusting element 18 . Moreover, the mounting part 15 has integrated in it a separately insertable damper 19 , designed, for example, as a fluid damper, of a damper arrangement, the damper characteristic of which can be set or adjusted. The damper 19 comprises a housing 19 a which receives displaceably a piston, not shown, to which a piston rod 19 b projecting out of the housing 19 a is connected. An operating handle 20 is connected to the housing 19 a on the outside via clamping jaws 20 a. The piston rod 19 b is connected to the lower end of the setscrew 17 .
[0044] A connecting pin 21 serves for the connection of the mounting part 15 and of the place-on part 16 .
[0045] For directed action upon the damper 19 , a control is provided, which comprises an operating lever 22 which is connected to the housing 19 a and which is mounted pivotably on the place-on part 16 via a bore 23 in the operating lever 22 , a bore 25 in the place-on part 16 and an axle pin 24 passing through the bores 23 and 25 , with a pivot axis which runs parallel to the axes of articulation 8 to 14 . To couple the pivoting movement of the operating lever 22 to the translational movement of the housing 19 a, the operating lever 22 is designed as a two-armed lever. The operating lever 22 is connected in an articulating manner, at its end facing the place-on part 16 , via an axle pin 26 to the operating handle 20 via a further bore 28 on the end face on the operating lever 22 and a bore 27 in the operating handle 20 . At the end facing away from the place-on part 16 , the operating lever 22 is provided with a meshing portion in the form of profiling, in the form of a nose 29 which projects laterally to the longitudinal extent and which temporarily or in-phase interacts or is coupleable and uncoupleable with respect to a guide portion 30 on a guide lever 31 .
[0046] The guide portion 30 in the guide lever 31 comprises a slightly curvedly running groove 30 a, as can be seen particularly according to FIGS. 3 b and 4 b in the middle longitudinal section through the guide lever 31 , with a groove depth which corresponds approximately to the height of the projecting nose 29 . The groove 30 a terminates, closed, in the guide lever 31 , and, for coupling and uncoupling the nose 29 with respect to the guide portion 30 reliably and smoothly, the groove 30 a widens at its open end via a widening or laterally funnel-shaped threading-in portion 30 b. The nose has correspondingly, for exact unthreading and threading in or sliding in the groove 30 a, in section a configuration half-sidedly convex and half-sidedly flat.
[0047] Instead of the guide groove, a long hole open on the end face, an indentation, a slotted-link guide, etc. may be formed.
[0048] The guide lever 31 has in the end in each case bores 31 a, 31 b, via which the guide lever 31 is tension-mounted between the axle pins 13 a and 14 a or the corresponding joints 13 and 14 . Consequently, the guide lever 31 is co-moved correspondingly with that part of the second cross arm 5 which is moved during the pivoting action by means of the hinge 1 . This also becomes clear from FIGS. 3 a and 4 a , according to which the guide lever 31 , in FIG. 3 a , stands, correspondingly to the intermediate position shown, with its longitudinal orientation approximately perpendicular to the longitudinal extent of the body hinge part 2 and, in FIG. 4 a , is inclined about 45 degrees of angle to the right by means of the hinge 1 in an end position of the pivoting mechanism. These positions correspond to the respectively associated pivoting positions of the second cross arm 5 .
[0049] Basically, the guide portion or the guide lever 31 and the further lever or the actuating lever 22 can be present elsewhere in the hinge 1 or in other hinges.
[0050] Moreover, the hinge 1 has, integrated in the first cross arm 4 , a draw-in arrangement 32 which, on a last portion of the pivoting movement before a closing position according to FIG. 4 a is reached, automatically presses or draws the hinge 1 into the closed end position according to FIG. 4 a via two integrated helical springs 33 , 34 and a pressure plate 35 when a predeterminable pivoting position of said hinge is reached, the closing force necessary for this purpose being implemented by the two prestressed helical springs 33 , 34 . In this case, after blocking of the draw-in arrangement 32 is cancelled, this taking place, for example, during the closing of a furniture part M on a body K by means of the hinge 1 at a predeterminable pivot point, the helical springs 33 , 34 act upon the pressure plate 35 such that the latter is displaced in the direction of the connecting arm 6 , so that damped closing of the furniture part M into the end position according to FIG. 4 a occurs. Shortly after the draw-in arrangement 32 has been activated, during the further closing movement the damper arrangement 19 is subsequently likewise activated by the coupling of the actuating lever 22 , on the one hand, to the guide lever 31 and, on the other hand, to the operating handle 20 .
[0051] The draw-in arrangement 32 is held on the cross arm 4 via two cotter pins 36 , 37 .
[0052] During the renewed opening of the movable furniture part M attached to the furniture part hinge part 3 in relation to the body K, the draw-in arrangement 32 is brought again into its prestressed position ( FIGS. 1 , 2 , 3 a ) and held in this, until, during a return movement by the pivoting of the hinge 1 as the respective furniture part is being closed, the predetermined draw-in position is resumed. Correspondingly, the damper arrangement 19 is brought into the position of readiness according to FIGS. 1 , 2 and 3 a again by the housing 19 a being pushed back into the position of readiness as a result of the action of the actuating lever 22 which pivots back correspondingly during the opening of the furniture part M.
[0053] Thus, when the furniture part M is being closed, during the pivoting action no shock-like bumping of the furniture part M against the body K can take place in spite of the automatic draw-in mechanism or slamming shut. When the closing movement is being damped, the housing 19 a is moved in the direction of a front end of the piston rod 19 b projecting out of the housing 19 a and held in a fixed position. This movement takes place in a damped or braked manner.
[0054] During the damping action, the operating lever 22 is pivoted clockwise according to the arrow P 1 in FIG. 3 b about the axle pin 24 in the bore 25 , so that the housing 19 a is displaced in relation to the free end of the piston rod 19 b according to the arrow P 2 in FIG. 3 a . During coupling, the nose 29 at the front of the operating lever 22 in the guide portion 30 is brought into the end position according to FIGS. 4 a and 4 b . During renewed opening or pivoting in the opposite direction, the damper housing 19 a is pushed back again into the position of readiness shown according to FIG. 3 a as a result of the interaction of the guide lever 31 and of the operating lever 22 .
LIST OF REFERENCE SYMBOLS
[0000]
1 Hinge
2 Body hinge part
3 Furniture part hinge part
4 Cross arm
5 Cross arm
6 Connecting arm
7 Connecting arm
8 to 13 Joint
8 a to 14 a Axle pin
14 Universal joint
15 Mounting part
16 Place-on part
17 Setscrew
18 Adjusting element
19 Damper
19 a Housing
19 b Piston rod
20 Operating handle
20 a Clamping jaw
21 Connecting pin
22 Operating lever
23 Bore
24 Axle pin
25 Bore
26 Axle pin
27 Bore
28 Bore
29 Nose
30 Guide portion
30 a Groove
30 b Threading-in portion
31 Guide lever
31 a, 31 b Bore
32 Draw-in arrangement
33 , 34 Helical spring
35 Pressure plate
36 , 37 Cotter pin
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A hinge for a movable furniture part fastened to a body of a piece of furniture is proposed, the hinge having a first fastening part which is attachable to the body and which is connected pivotably via a joint mechanism to a second fastening part attachable to the movable furniture part, the joint mechanism comprising articulated levers mounted via axes of articulation. According to the invention, a further pivotably mounted lever is present, which, during a complete as-intended pivoting movement of the hinge, is temporarily coupled to a guide portion on the hinge, the further lever acting upon a damper arrangement of the hinge.
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CROSS REFERENCE TO RELATED APPLICATIONS
This is a division of application Ser. No. 901,492, filed May 1, 1978, now U.S. Pat. NO. 4,208,226.
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates generally to fuels for heat production, such fuels being comprised primarily of the waste materials remaining after steel or pig iron production from iron ore.
II. Description of the Prior Art
Many thermit materials are well known for use as external heat producers for welding, for incendiary compositions, etcetera. Burch, in U.S. Pat. No. 2,402,947 describes a Flux Forming Fuel and Process. Jones, in U.S. Pat. No. 3,745,077 describes a Thermit Composition for use as an incendiary. Thermit materials have also been used as a retardant in conjunction with higher temperature reactants. Cox, in U.S. Pat. No. 3,181,937 teaches a device which employs this technique.
The term "thermit" generally refers to a mixture of iron oxides and aluminum which, when heated, reacts at temperatures of about 5000° F. The term "thermit" is also used to refer to a combination of any of several reducing metals with iron oxides. The reducing metal may be aluminum, magnesium, and the like. The following reactions are typical:
______________________________________8A1 + 3Fe.sub.3 O.sub.4 9Fe + 4Al.sub.2 O.sub.32Mg + Fe.sub.2 O.sub.3 2Fe + Mg.sub.2 O.sub.3.______________________________________
Many variations of this type reaction are known in the art. For example, Rejdak, in U.S. Pat. No. 3,020,610 teaches a variation of the method which is particularly useful for welding aluminum to aluminum. Also, see Rejdak's U.S. Pat. No. 3,033,672 which describes a method for welding copper to steel.
The reactions are exothermic and can react at temperatures in excess of about 6000° F. Interestingly, none of the methods to date have used either the method or the easily obtained materials of Applicant's invention. Heretofore, these reactions have typically employed chemically pure materials. Most applications direct the reaction heat to a localized area or specified material as in the case of welding or incendiary applications. Cost and availability of these relatively expensive materials have to data precluded use of such materials for commerical fuel requirements.
It is therefore an object of the present invention to overcome the cost and availability restrictions of conventional fuels and previously known thermit materials.
SUMMARY OF THE INVENTION
We have found that the foregoing and related objects can be attained by forming a composition wherein the primary ingredient is an iron-containing waste by-product from steel production or similar processes. These by-products had heretofore been merely disposed of.
Waste materials are combined with a concentrated mineral acid and retardants. Alternately, diluted acid may be used this requiring less water to make the mixture moldable in a later step. Aluminum, magnesium, or another reducing metal is added to enough water to make the mixture pliable. The mixture is then molded and is cured for a short period. Sufficient heating of a small portion induces reaction of the entire sample.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Applicants have devised a method of combining any of several iron-containing by-products with other materials to form a composition in either shaped or loose form to be used for heat production. Tests have shown that the exothermic heat produced by such compositions is so great in some cases that retardants such as sand or lime should be added to control the reaction and extend the reaction time.
Any of several by-products may be used. These include flue dust, mill scale, B.O.P. dust, filter cake, and sinter blends. In addition to the above list of by-products, any dust-like or powdery iron-containing waste product is suitable for the invention. Analysis of the materials was performed and all contain iron oxides. By way of example, the following result was obtained for B.O.P. dust.
______________________________________Substance Approximate % by weight______________________________________Free metallic iron 0.4Fe.sub.2 O.sub.3 49.0FeO 20.4Carbon 0.7H.sub.2 O (liquid) 1.0PbO 0.7ZnO 5.1CaO 11.3MnO 0.9P.sub.2 O.sub.5 0.1SiO.sub.2 1.7Al.sub.2 O.sub.3 0.5MgO 2.8Moisture 1.9______________________________________
B.O.P. dust is a by-product from steel production. Most steel production from iron ore involves two basic phases. The first phase melts iron ore in a blast furnace producing iron, clinkers, and in relatively small amounts several dust-like iron containing waste by-products. These dust-like by-products collect on the iron, in flues, and on other areas. The second phase of the steel production converts the aforementioned iron to steel in an electric furnace. This electric furnace process also produces relatively small amounts of iron-containing waste by-products. The by-products from both phases normally vary from about 30% to about 70% by weight iron.
It is the scheme of the present invention to utilize the aforementioned waste by-products for heat production and various industrial, commercial, or consumer applications such as, for example, production of steam.
Some examples of the composition and method of the invention are given below. It is not intended that the invention be limited to the by-products, compositions, or methods used in these examples.
EXAMPLE 1
Materials:
60 ounces of wet filter cake in a slurry
40 ounces of dry B.O.P. dust
20 ounces of dry filter cake
24 ounces of aluminum powder with the largest dimension of any aluminum particle no larger than about 1/8 inch
7.5 ounces of lime retardant
5 ounces of a solution of 20% by weight hydrochloric acid
Method:
The lime retardant is added to the three waste by-products. The acid is added and the composition is mixed well and then allowed to stand for six hours. Enough water is added to make the composition moldable. The aluminum is added. The composition is mixed well, poured into a mold, and pressed at a pressure of about ten pounds per square inch or more. This mold is then allowed to cure by standing for about three hours. While the mixture stands, it is observed that heating occurs to such a temperature that steam is given off and the composition then usually hardens to a dimensionally stable form or brick. A portion of the resulting product is then heated by an electric arc. An initial reaction temperature of greater than 3000° F. is required. The composition burns at a linear rate of about 0.85 inches per minute, reaches a maximum temperature of about 6000° F., and produces heat calculated to be about 200,000 BTU per pound of composite. This can be compared with bituminous coal which yields about 12,000 BTU per pound.
EXAMPLE 2
Materials:
40 ounces of black filter cake slurry
10 ounces of B.O.P. dust
10 ounces of aluminum powder with the largest dimension of any aluminum particle no larger than about 1/8 inch
3 ounces of water
2 ounces of hydrochloric acid solution, 20% by weight
Method:
Procedure used was the same as in Example 1. A propane torch of approximately 3400° F. was used to heat a portion of the reaction mixture. Reaction is spontaneous with a linear burn ,ate of about 0.27 inches per minute, a maximum temperature of about 6000° F., and heat production is calculated to be about 200,000 BTU per pound of composite.
EXAMPLE 3
Materials:
40 ounces of dry B.O.P. dust
60 ounces of filter cake slurry
18 ounces of aluminum with the largest dimension of any particle no larger than about 1/8 inch
7 ounces of lime
7 ounces of bituminous coal
7 ounces of hydrochloric acid solution, 20% by weight
Method:
Again, the procedure used was the same as that in Example 1 except that bituminous coal was also added. Ignition of a portion of the sample by electric arc in excess of 4000° F. produced a linear burn rate of 1.61 inches per minute, a maximum temperature of about 6000° F., and resulting heat calculated to be about 200,000 BTU per pound.
The aluminum or other reducing metal is preferably smaller than about 1/10 inch in its largest dimension. Any mineral acid is effective in the process either alone or in combination, but hydrochloric acid is preferred.
The burn rate can be controlled by variation of the portions of retardant, waste material, or reducing metal. The materials should fit within the parameters listed below:
______________________________________Material Parameter______________________________________Iron-containing by-products: at least about 50 to 95% of the composite mixtureReducing metal: about 12 to about 25% by weight of the iron-con- taining by-productRetardant: less than about 40% by weight of iron-containing by-productAcid: about 2% to about 10% by weight of the iron con- taining by-productWater: enough to make the mixture pliable.______________________________________
Tests have indicated that these compositions burn well with coal as in Example 3. Aluminum "dross", an impure aluminum waste, has been used in pulverulent form in lieu of commercially purchased metal. This has proven effective for the reaction when used in sufficient quantity and again, lowers the cost of the composition.
Having described our invention it is not intended that the examples in any way limit the scope of the invention as other variations of the composition and method will become apparent to one skilled in the art.
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Waste materials from the conversion of iron ore to pig iron or steel combine with a reducing metal, such as aluminum or magnesium, and a small portion of a mineral acid to form a reaction mixture which gives a heat output superior to many conventional fuels. The materials are processed in several steps to produce either a shaped or loose composition, a portion of which is then heated to a reaction temperature. Retardants for the reaction may be added.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a liquid crystal display apparatus, and more particularly to a liquid crystal display apparatus which is capable of preventing a break due to a crack caused during a manufacturing process.
2. Discussion of the Background
A liquid crystal display apparatus, an important man-machine communications device, is used in a variety of electronic devices such as electronic watches, personal digital assistant (PDA) systems, word processors, copying machines, facsimile machines, and so on. In the liquid crystal display apparatus, a polymer substrate has been widely employed in place of a glass substrate. Utilizing a polymer substrate is a known technique and is described in, for example, Japanese Laid-Open Patent Application No. 07-043697 (1995) referring to an exemplary structure of a liquid crystal display apparatus shown in FIG. 1 . The liquid crystal display apparatus of FIG. 1 has a typical structure which includes a pair of polymer substrates 1 and 2 , indium-tin oxide (ITO) electrodes 3 and 4 , a sealing member 5 , a liquid crystal 6 , and polarizing seals 10 and 11 . The ITO electrodes 3 and 4 are bonded on the sides of the polymer substrates 1 and 2 to face each other. The sealing member 5 is deposited between the ITO electrode films 3 and 4 around the edge of the ITO electrode film 3 so that the liquid crystal 6 is sealed therein. In the liquid crystal display apparatus having the structure mentioned above, the liquid crystal 6 is energized to display information in a form of alphanumeric symbols, for example, by applying an electrical current to the ITO electrodes 3 and 4 .
In general, a liquid crystal display apparatus having the above-described structure is used as part of an electronic device (not shown), for example, and is therefore mounted inside a housing or the like of the electronic device. FIG. 1 shows a connecting portion of the electronic device and the liquid crystal display apparatus. The electronic device includes a connecting member 7 , a solder 8 , bumps 8 a , and an electrode 9 . The connecting member 7 is extended from a circuit substrate (not shown) or the like of the electronic device to supply power to the liquid crystal display apparatus. For this purpose, an extension 2 a is extended from the polymer substrate 2 and an electrode extension 4 a is extended from the ITO electrode 4 along the extension 2 a.
To electrically connect the electrode extension 4 a to the connecting member 7 , the electrode extension 4 a is typically pressed against the connecting member 7 and is then soldered with the solder 8 , which is deposited together with the bumps 8 a between the electrode 9 bonded on the bottom of the connecting member 7 and the electrode extension 4 a.
However, the above-mentioned way of connecting the liquid crystal display apparatus to the electronic device provides a stress to the electrode extension 4 a on the electrode 4 or to the electrode extension 4 a at a position under the sealing member 5 , which may generate a crack 12 . This may eventually cause a failure of electrical connection between the liquid crystal display apparatus and the circuit substrate of the electronic device. As a result, the liquid crystal cannot properly display information. This kind of error may be caused not only when the electrode extension 4 a is connected to the connecting member 7 using heat and pressure, but also when the electrode extension 4 a receives an excessive stress during the installation of the liquid crystal display to the electronic device.
One technique for preventing this problem is to extend the polarizing seal 11 to cover the length of the extension of the polymer substrate 2 a so as to support the electrode extension 4 a . However, this technique is not sufficient because such a technique would be effective only after the extended polarizing seal 11 is attached and the electrode extension 4 a may receive a stress and may be bent, as shown by dotted lines in FIG. 2, before the extended polarizing seal 11 is attached.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a novel liquid crystal display apparatus which eliminates the unstable connection problems as discussed above.
To achieve this object and other objects, a novel liquid crystal display apparatus of the present invention includes a substrate kit and an assembling member. The substrate kit includes first and second polymer substrates, each of which has an electrode on an entire surface of one side thereof. The first and second polymer substrates are deposited in parallel in a horizontal direction such that the electrodes face each other, and have a sealing member deposited therebetween around a circumference thereof such that a sealed space is made by the electrodes and the sealing member. The first polymer substrate forms a substrate extension extending outwards in a horizontal plane and the electrode bonded on the first polymer substrate forms an electrode extension extending along the substrate extension.
The substrate kit further includes a liquid crystal which is sealed inside the sealed space, polarizing seals bonded on each of the pair of polymer substrates on a side opposite to the side having the electrode, and an assembling member on which the substrate kit is mounted. In such a liquid crystal display apparatus, at least a portion of the electrode extension is bent in a direction towards the second polymer substrate before the substrate kit is mounted on the assembling member.
The polarizing seal bonded on the first polymer substrate may be extended approximately to an end of the substrate extension.
The electrode extension may be bent at an angle from 2 degrees to 20 degrees, or with a radius of curvature in a range of 10 mm to 100 mm.
Further, the assembling member may include a supporting frame for supporting the apparatus. The supporting frame may have a surface contacting the second polymer substrate and a rise at one end which engages a rim of the electrode extension such that the electrode extension is bent in a direction towards the second polymer substrate.
Further, the assembling member may include a supporting frame for supporting the apparatus. The supporting frame may include a surface contacting the first polymer substrate and, at one end, a slope having an angle from 2 degrees to 20 degrees. In this case, the slope is used to bend the electrode extension in a direction towards the second polymer substrate.
Further, when the apparatus mounted on the assembling member is installed in a different housing, a part of the different housing may hold the assembling member so as to secure the electrode extension.
Other objects, features, and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
FIGS. 1 and 2 are illustrations for explaining a typical structure of a liquid crystal display of a backgound art;
FIG. 3 if an illustration for explaining an exemplary structure of a liquid crystal display apparatus having extensions of a substrate, electrode, and polarizing seal with a slope having a predetermined angle, according to an embodiment of the present invention;
FIG. 4 is an illustration for explaining an exemplary structure of a liquid crystal display apparatus having extensions of a substrate, electrode, and polarizing seal with a curve having a predetermined radius of curvature, according to an embodiment of the present invention;
FIGS. 5-7 illustrations each for explaining a way of mounting the liquid crystal display apparatus on an assembling frame; and
FIG. 8 is an illustration for explaining an exemplary structure in which the liquid crystal display apparatus according to the present invention and mounted on an assembling frame is installed inside a console panel of a copying machine.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the present invention is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents which operate in a similar manner.
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIG. 3 thereof, there is illustrated an exemplary structure of a liquid crystal display apparatus 34 according to an embodiment of the present invention. While FIG. 3 shows an edge portion of the liquid crystal display 34 , the entire apparatus has a box shape although it is not shown.
In FIG. 3, the liquid crystal display 34 includes a pair of polymer substrates 21 and 22 , ITO (indium-tin oxide) electrodes 23 and 24 , a sealing member 25 , a liquid crystal 26 , and a pair of polarizing seals 27 and 28 . The ITO electrodes 23 and 24 are bonded to the polymer substrates 21 and 22 , respectively, such that the ITO electrodes 23 and 24 face each other with a distance to form a space for holding the liquid crystal 26 therebetween. Both of the polymer substrates 21 and 22 have a side in the vertical direction of the drawing, along which the sealing member 25 is disposed so as to seal the liquid crystal 26 held in the space between the electrodes 23 and 24 .
When an electric current passes through the electrodes 23 and 24 configured in the above-mentioned way, the liquid crystal 26 is energized and displays information in a predetermined form, such as alphanumeric symbols or the like.
The polarizing seals 27 and 28 are also bonded to the polymer substrates 21 and 22 , respectively, on sides of the polymer substrates 21 and 22 opposite to those having the electrodes 23 and 24 , as shown in FIG. 3 . The polarizing seals 27 and 28 may be substituted by semi-transparent seals or reflective seals.
The polymer substrate 22 forms at one end a substrate extension 22 a which extends in an external direction over the sealing member 25 . Along the substrate extension 22 a , the electrode 24 also forms an electrode extension 24 a for a predefined length. Also, the polarizing seal 28 extends its end along the substrate extension 22 a nearly to the ends of the substrate extension 22 a and the electrode extension 24 a.
The electrode extension 24 a which extends from the electrode 24 over the sealing member 25 is bent at a portion around the sealing member 25 , e.g., slightly outside the sealing member 25 , in a direction towards the polymer substrate 21 with an angle θ, which may be in the 2-degree to 20-degree range. Such a bent electrode extension 24 a is installed in an assembling frame (explained later). The electrode 24 may alternatively be bent around its mid portion or any portion other than the portion around the sealing member 25 .
The electrode extension 24 a is electrically connected, e.g., via bumps 31 to an electrode 30 of a connecting member 29 which is a part of a heat seal connector or the like mounted on a circuit substrate (not shown). The electrode 30 is fixed to the electrode extension 24 a with, e.g., a solder 32 . Accordingly, the electrode 24 is connected to the connecting member 29 through the electrode extension 24 a and can be applied with a power therethrough to cause the liquid crystal 26 to display information in a form such as alphanumeric symbols or the like.
In the present embodiment, the liquid crystal display apparatus 34 with the electrode extension 24 a being bent with the angle θ within the 2-degree to 20-degree range allowance is assembled in an assembling frame. Then, the electrode extension 24 a is made to contact the connecting member 29 via the bumps 31 with a pressure, and heat is applied to melt the solder between the electrode 30 and the electrode extension 24 a . Thereby, the electrode extension 24 a is connected to the connecting member 29 .
In this way, the liquid crystal display apparatus 34 can be installed in the assembling frame with the electrode extension 24 a which has previously been bent towards the polymer substrate 21 relative to the surface of the electrode 24 . Accordingly, when the liquid crystal display apparatus 34 is installed in the assembling frame, the electrode extension 24 a is positioned at a place where it can contact the electrode 30 of the connecting member 29 without causing a mechanical stress thereon. Accordingly, the electrode extension 24 a can be connected safely with the connecting member 29 . Even if a crack 33 occurs on the portion of the electrode 24 or the electrode extension 24 a where the bend is made, the electrode extension 24 a can be connected safely with the connecting member 29 since the electrode extension 24 a will not receive a stress during the connecting process. As a result, the electrical connection can be made stably between the electrode 30 of the connecting member 29 and the electrode extension 24 a , which avoids a failure in displaying information.
As described above, the polarizing seal 28 also has an extended portion with the predetermined angle θ. This extended portion supports the electrode extension 24 a from the bottom thereof, protecting the electrode extension 24 a from being bent to an extent exceeding a predetermined angle and from generating the crack 33 around the portion being bent.
As also described above, the electrode extension 24 a is bent with the angle θ within the 2-degree 20-degree range, thereby making good contact with the electrode 30 of the connecting member 29 even if the electrode extension 24 a has the crack 33 at the portion where the bend is made. The experimental reasons for predetermining the angle θ within the 2-degree to 20-degree range are as follows. With the angle θ smaller than 2 degrees, the electrode extension 24 a may need to be bent at a further angle during the process of connecting to the connecting member 29 . In this case, if the crack 33 already exists, such a crack 33 may become greater and, as a result, the electrode extension 24 a may not make good contact with the electrode 30 . With the angle θ greater than 20 degrees, the electrode extension 24 a may need to be bent back during the process of connecting to the connecting member 29 . In this case, if the crack 33 already exists, such a crack 33 may become greater and, as a result, the electrode extension 24 a may not make good contact with the electrode 30 . Accordingly, the safety range of the angle θ is in the 2-degree to 20-degree range. This range may be expanded in certain cases, e.g. based on materials used for the elements. However, from a practical view point, it is more preferable to set the angle θ to a degree within a 5-degree to 15-degree range.
Alternative to the way of bending in which the electrode extension 24 a is bent linearly, as shown in FIG. 3, the electrode extension 24 a can be bent with a curve having a radius of curvature within a range from 10 mm to 100 mm, as shown in FIG. 4 . This alternative bending way provides a margin to the connecting tension between the electrode extension 24 a and the connecting member 29 . Therefore, the electrode extension 24 a can maintain a good contact with the electrode 30 of the connecting member 29 against an external stress even if the electrode extension 24 a has the pre-formed crack 33 around the portions close to the sealing member 25 and/or the bumps 31 as well as the melted solder 32 , as shown in FIG. 4 . As described above, the range from 10 mm to 100 mm is the safety range of curvature radius. However, from a practical view point, it is more preferable to set the radius of curvature within a 15 mm to 50 mm range.
Next, a first example of an assembling frame which supports the liquid crystal display apparatus 34 is explained with reference to FIG. 5 . In FIG. 5, reference numeral 41 denotes an assembling frame which supports the liquid crystal display apparatus 34 . The assembling frame 41 includes a contact surface 41 a which contacts the side of the polymer substrate 21 of the liquid crystal display apparatus 34 . The assembling frame 41 further includes a side end 42 on which a pawl 42 a is formed, as shown in FIG. 5 .
In FIG. 5, the liquid crystal display apparatus 34 and a back light mechanism (not shown) using, e.g., an LED (light-emitting diode) or an EL (electroluminescence) are assembled in the assembling frame 41 , and then the electrode extension 24 a is engaged in the pawl 42 a so that the electrode extension 24 a is bent in the direction towards the side of the polymer substrate 21 . With this structure, the electrode extension 24 a can be bent easily without requiring extra steps during the manufacturing procedure. As a result, the number of the assembling steps of the liquid crystal display apparatus 34 can be prevented from increasing.
In the assembling frame 41 of FIG. 5, the electrode extension 24 a is set to the angle of 4 degrees when the length of the electrode extension 24 a is 2.7 mm and when the pawl 42 a is bent in the direction towards the side of the polarizing seal 27 so that the bottom surface of the pawl 42 a is lowered 0.2 mm relative to the polarizing seal 27 .
Next, a second example of an assembling frame which supports the liquid crystal display apparatus 34 is explained with reference to FIG. 6 . In FIG. 6, reference numeral 51 denotes an assembling frame which supports the liquid crystal display apparatus 34 . The assembling frame 51 includes a contact surface 51 a which contacts the side of the polymer substrate 22 of the liquid crystal display apparatus 34 . The contact surface 51 a has at one end a slope having an angle θ within a range from 2 degrees to 20 degrees.
With this structure, when the liquid crystal display apparatus 34 is installed in the assembling frame such that the side of the polymer substrate 22 faces the side of the contact surface 51 a , the electrode extension 24 a is placed on this slope of the contact surface 51 a and is accordingly bent in the direction towards the polymer substrate 21 .
After the above-described installation, the liquid crystal display apparatus 34 is fixed to the assembling frame 51 by a fixing member 52 which supports the assembling frame from the bottom thereof and the electrode extension 24 a from the top.
With this structure, the electrode extension 24 a can be bent easily without requiring extra steps during the manufacturing procedure. As a result, the number of the assembling steps of the liquid crystal display apparatus 34 can be prevented from increasing.
Next, a third example of an assembling frame which supports the liquid crystal display apparatus 34 is explained with reference to FIG. 7 . In FIG. 7, reference numeral 61 denotes an assembling frame which supports the liquid crystal display apparatus 34 . The assembling frame 61 includes a contact surface 61 a which contacts the side of the polymer substrate 22 of the liquid crystal display apparatus 34 . The contact surface 61 a has at one end a curving slopel having a curvature radius S within a range from 10 mm to 100 mm.
With this structure, when the liquid crystal display apparatus 34 is installed in the assembling frame such that the side of the polymer substrate 22 faces the side of the contact surface 61 a , the electrode extension 24 a is placed on this curving slope of the contact surface 61 a and is accordingly bent in the direction towards the polymer substrate 21 .
After the above-described installation, the liquid crystal display apparatus 34 is fixed to the assembling frame 61 by a fixing member 62 which supports the assembling frame from the bottom thereof and the electrode extension 24 a from the top.
With this structure, the electrode extension 24 a can be bent easily without the need of extra steps during the manufacturing procedure. As a result, the number of the assembling steps of the liquid crystal display apparatus 34 can be prevented from increasing.
Next, an exemplary structure of a machine console where the liquid crystal display apparatus 34 is installed is explained with reference to FIG. 8 . In FIG. 8, reference numeral 71 denotes a console of a machine such as a copying machine, a facsimile machine, or the like, in which the liquid crystal display apparatus 34 assembled in the assembling frame 61 is installed. The console 71 includes a printed circuit board (PCB) 72 at the inside bottom thereof, and a supporting member 71 a which extends from the upper interior wall of the console 71 and holds down the electrode extension 24 a.
With this structure, the liquid crystal display apparatus 34 can be fixed in the console without requiring extra parts for holding down the fixing member 62 . Accordingly, it becomes possible to minimize the distance between the console 71 and the liquid crystal display apparatus 34 inside the console 71 . As a result, the console 71 can be made thinner.
In addition, with the above-described structure, the liquid crystal display apparatus 34 can be fixed to the fixing member 62 without using a dual-sided adhesive tape or the like. Accordingly, the number of the assembling steps of the liquid crystal display apparatus 34 can be prevented from increasing.
Obviously, numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.
This document claims the priority rights of and is based on the subject matter described in Japanese patent application JPAP 10-170830 filed on Jun. 18, 1998, in the Japanese Patent Office, the entire contents of which are hereby incorporated by reference.
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A novel liquid crystal display apparatus includes a substrate kit and an assembling member. The substrate kit includes first and second polymer substrates on which electrodes are mounted and which are deposited in parallel in a horizontal direction such that the electrodes face each other. A sealing member is deposited around a circumference of the first and second polymer substrates such that a sealed space is made by the electrodes and the sealing member. The first polymer substrate forms a substrate extension extending outwards in a horizontal plane and the electrode bonded on the first polymer substrate forms an electrode extension extending along the substrate extension. The substrate kit further includes liquid crystal sealed inside the sealed space, polarizing seals bonded on each of the pair of polymer substrates on sides opposite to the sides having the electrodes, and an assembling member on which the substrate kit is mounted. In such a liquid crystal display apparatus, at least a portion of the electrode extension is bent in a direction towards the second polymer substrate before the substrate kit is mounted on the assembling member.
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TECHNICAL FIELD
The present invention relates to fuel cells; more particularly, to fuel cells wherein a gaseous fuel such as hydrogen or reformed gasoline is flowed across the surface of an anode layer; and most particularly, to such a fuel cell wherein means is included for distributing fresh fuel to all portions of the anode layer surface.
BACKGROUND OF THE INVENTION
Fuel cells are well known as devices for converting chemically-stored energy directly into electricity. One such type of fuel cell employs a solid-oxide electrolyte having a cathodic layer deposited on a first surface and an anodic layer deposited on a second and opposite surface. Oxygen atoms are reduced to O −2 by the cathodic layer, migrate through the electrolyte, and unite with protons produced from hydrogen by the anodic layer to form water, and, in the case of reformed gasoline, with CO to form CO 2 . Electrons flow from the anode via an external path to the cathode through the cell interconnect.
A plurality of such fuel cells may be assembled in series to form a fuel cell stack. The individual fuel cells are electrically connected to each other by interconnect elements between the electrodes to maintain electrical continuity. Each interconnect is mechanically and electrically connected on one side through a fuel flow space to an adjacent anode and on the other side through an air flow space to an adjacent cathode. Such connection is known to be provided by incorporation of conductive filaments or metallic sponge in the respective gas flow spaces between the electrodes and the interconnects.
Oxygen is provided to the cathode surface, typically in the form of air, in abundance as a coolant as well as an oxidant for the fuel cell. Fresh air is introduced via a first inlet manifold means to the air flow space at an entry edge of the cathode surface, flows across the surface, and is removed via a first exit manifold at an exit edge of the cathode surface. Hydrogen-containing gas is introduced via a second inlet manifold means to the fuel flow space at an entry edge of the anode surface, flows across the surface, and is removed via a second exit manifold at an exit edge of the anode surface. Typically, but not necessarily, such a fuel cell is rectangular in plan view, and the oxygen and fuel flow through the fuel cell orthogonally to each other.
A serious problem is known in the art which adversely affects both fuel utilization efficiency and electrical output of the cell or stack. The anode surface near the entry edge is exposed to fresh fuel with no combustion byproducts in it, such as H 2 O and CO 2 . Thus, the reaction rate and electricity production is relatively high in this region of the anode. However, as the fuel sweeps across the anode toward the exit edge, it picks up, and becomes diluted by, such byproducts while simultaneously becoming relatively depleted of H 2 and CO. Thus, the reaction rate and electricity production become progressively reduced in anode regions farther from the entry edge. Because of this phenomenon, these regions of the anode are sub-optimized, or under-utilized, in production of electricity.
Further, a relatively large and potentially damaging temperature difference may result between high-reaction and low-reaction areas of the anode.
Therefore, there is a strong need for an improved means for distributing fuel more uniformly over all portions of the anode surface.
It is a principal object of the invention to improve temperature uniformity within a fuel cell.
SUMMARY OF THE INVENTION
Briefly described, the present invention is directed to an improved interconnect system for more uniformly distributing gaseous fuel over the anode surface of a fuel cell. The system comprises an interconnect subassembly for electrically connecting anodes and cathodes of adjacent fuel cells in a fuel cell stack. The subassembly includes a perforated distributor plate disposed adjacent the anode surface. The distributor plate may be parallel to or inclined to the anode surface and forms a first wall of a fuel plenum for uniformly distributing fuel via the perforations over the entire surface of the anode. The second wall of the plenum is a second, imperforate plate separating the fuel flow plenum from air flowing across the adjacent cathode. Electrical continuity across the interconnect subassembly may be provided by non-planar upsets in the two plenum plate components, such as bumps and dimples, or by metallic foam or filaments disposed between the plates and the electrodes.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features, and advantages of the invention, as well as presently preferred embodiments thereof, will become more apparent from a reading of the following description in connection with the accompanying drawings in which:
FIG. 1 is a schematic elevational cross-sectional view of a first prior art interconnect element disposed between adjacent fuel cells in a fuel cell stack, showing upsets in the interconnect plate, in the form of bumps and dimples, for making electrical contact with the anode and cathode of the adjacent interconnected fuel cells;
FIG. 2 is a schematic elevational cross-sectional view of a second prior art interconnect element disposed between adjacent fuel cells in a fuel cell stack, showing metallic sponge and conductive filaments for making electrical contact with the anode and cathode of the adjacent interconnected fuel cells;
FIG. 3 is a schematic elevational cross-sectional view of a first embodiment of a combined interconnect and fuel distribution system in accordance with the invention;
FIG. 4 is an exploded isometric view from above of the embodiment shown in FIG. 3 ;
FIG. 5 is a detailed plan view of a portion of a perforated distribution plate for forming a first wall of a fuel plenum in accordance with the invention, showing a currently preferred arrangement of perforations, bumps, and dimples;
FIG. 6 is a detailed plan view of a portion of a plate forming a second wall of the fuel plenum, showing a currently preferred arrangement of bumps; and
FIG. 7 is a schematic elevational cross-sectional view of a second embodiment of an interconnect fuel distribution system in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 , a first embodiment of a prior art interconnect 10 is disposed in a portion of a fuel cell stack 12 . Stack 12 includes a first fuel cell 14 a and a second fuel cell 14 b , interconnect 10 providing electrical conductivity therebetween. First fuel cell 14 a includes a solid-oxide electrolyte 16 a having a planar anode layer 18 a attached to one surface thereof and a planar cathode layer 20 a attached to an opposite surface thereof to define a fuel cell or PEN (positive-electrolyte-negative assembly). Second fuel cell 14 b is identically constructed of analogously numbered components and includes a solid-oxide electrolyte 16 b having a planar anode layer 18 b attached to one surface thereof and a planar cathode layer 20 b attached to an opposite surface thereof to define a fuel cell or PEN. Interconnect 10 includes an electrically-conductive plate 22 having a plurality of non-planar upsets extending away from both planar surfaces of plate 22 in the form of “bumps,” defined herein as upsets extending toward a cathode, and “dimples,” defined herein as upsets extending toward an anode. Bumps 24 are formed in plate 22 in mechanical and electrical contact with the surface of cathode 20 a in the first fuel cell PEN 14 a , serving to offspace plate 22 from cathode 20 a and thereby defining an air flow space 26 therebetween for supply of air 28 to the cathode surface. Dimples 30 are in mechanical and electrical contact with the surface of anode 18 b in the second fuel cell PEN 14 b , serving to offspace plate 22 from anode 18 b and thereby defining a fuel flow space 32 therebetween for supply of fuel 34 to the anode surface. Bumps 24 and dimples 30 typically are arranged in predetermined patterns, which may or may not be regular, and the air and fuel flow through their respective spaces 26 , 32 around the bumps and dimples.
Referring to FIG. 2 , a second embodiment of a prior art interconnect 10 ′ is disposed in a portion of a fuel cell stack 12 ′ including a first fuel cell PEN 14 a and second fuel cell PEN 14 b , interconnect 10 ′ providing electrical conductivity therebetween. Interconnect 10 ′ includes an electrically-conductive plate 22 ′ disposed between PENs 14 a , 14 b to form flow spaces 26 , 32 , as in the first embodiment. Instead of bumps and dimples to provide conductivity, interconnect 10 ′ includes either a porous metallic foam 36 , for example, foamed nickel, or a plurality of conductive filaments 38 extending from plate 22 ′ to cathode 20 a and anode 18 b .
As described above, the prior art embodiments as shown in FIGS. 1 and 2 are unable to prevent fuel from undergoing a continuous change in composition between the entry edge 40 and the exit edge 42 of anode 18 b , by continuous reaction and removal of combustibles and continuous addition of combustion products.
Referring to FIGS. 3 and 4 , a first embodiment 110 of an improved interconnect and fuel distribution system in accordance with the invention, included in an improved fuel cell stack 112 , includes a first interconnect plate 122 similar to prior art plate 22 , having bumps 124 and dimples 130 extending from opposite sides of plate 122 , the dimples 130 forming electrical contact with anode 18 b as in the prior art to create a fuel flow space 132 for flow of fuel 34 adjacent anode 18 b . Disposed between first plate 122 and cathode 20 a is a second interconnect plate 144 having bumps 124 ′ extending into electrical contact with cathode 20 a and thereby forming an air flow space 126 therebetween for flow of air 28 along cathode 20 a . Second plate 144 is off-spaced from first plate 122 by the height of bumps 124 , which bumps alternatively may be provided as dimples in plate 144 to equal effect, to form a plenum 146 therebetween for receiving fuel 34 , which in operation fills plenum 146 . First plate 122 is provided with a plurality of holes 148 extending between plenum 146 and fuel flow space 132 for allowing the fuel to flow from the plenum into the flow space. While the average mass flow from entry edge 40 to exit edge 42 is the same as in the prior art fuel cell stacks, the composition of the gas experienced by the anode surface is very different. The number of holes 148 , their spacing, and the pattern of holes are such that all portions of the anode surface continually receive fresh fuel through holes 148 from plenum 146 . Although a contaminant gradient must still exist in the fuel between entry edge 40 and exit edge 42 , because combustion is still occurring over the entire surface, the gradient is much diminished over that in prior art stack 12 by admixture of fresh fuel to spent fuel over the whole surface.
Referring to FIG. 4 , a fuel cell stack 112 may include other mechanical components not shown schematically in FIG. 3 . As noted previously, air and fuel flow through a fuel cell stack preferably in orthogonal directions. Thus all four peripheries of the elements are provided with flow passages for supplying and exhausting air and fuel. As in the prior art, air 28 is introduced at the lower left of the stack, as shown isometrically in FIG. 4 , and flows upwards through inlet air ports 50 in the various elements until it reaches distribution spacer 52 wherein the inlet ports 54 are open to air flow space 126 , spacer 52 being substantially the same thickness as the height of bumps 124 ′. Spacer 52 is sealed to cathode 20 a by a first perimeter seal 56 . Air 28 flows across the surface of cathode 20 a and exits the flow space via matching exhaust ports similar to inlet ports 54 , 50 (not visible in FIG. 4 ).
A similar distribution system is provided for fuel in the orthogonal direction. Fuel 34 enters the stack from the lower back side, flows upwards through inlet fuel ports 58 in PEN 14 b and first interconnect plate 122 until it reaches fuel entry distribution spacer 60 wherein the fuel inlet ports in spacer 60 (not visible in FIG. 4 ), similar in shape to fuel inlet ports 66 in spacer 64 , are open to plenum 146 , spacer 60 being substantially the same thickness as the height of bumps 124 . Note that the fuel exhaust ports 63 in the opposite edge of first spacer 60 are not open to plenum 146 . Consequently, fuel flows through holes 148 in plate 122 into fuel flow space 132 . A fuel distribution exit spacer 64 is provided between anode 18 b and plate 122 having open fuel exhaust ports 66 connecting to fuel exhaust ports 68 . Spacer 64 is sealed to anode 18 b by a second perimeter seal 56 ′.
Referring to FIGS. 5 and 6 , a currently-preferred pattern of holes 148 , bumps 124 , and dimples 130 is shown for a representative portion of plate 122 (FIG. 5 ), the repeating module 55 being a hole bracketed by two bumps in a first direction and by two dimples in a second direction, and a currently-preferred pattern of bumps 124 ′ is shown for a representative portion of plate 144 (FIG. 6 ). In the currently-preferred assembly relationship, bumps 124 ′ are positioned directly over dimples 130 (as shown in FIG. 3 ). Bumps 124 ′ are actually dimples on the underside of plate 144 , from the perspective of plate 122 . The preferred assembly relationship thus provides planar regions 67 between bumps 124 ′ for receiving bumps 124 .
Referring to FIG. 7 , a second embodiment of an improved interconnect 110 ′ and fuel distribution system in accordance with the invention is shown in an improved fuel cell stack 112 ′. System 110 ′ is similar in many respects to improved system 110 , having a first interconnect distribution plate 122 ′ and a second interconnect plate 144 ′ forming a plenum 146 ′ therebetween. Plate 122 ′ is provided with a plurality of holes 148 ′ for distribution of fuel 34 through plate 122 ′ over all portions of the surface of anode 18 b . Second plate 144 ′ may be substantially identical to plate 144 in embodiment 110 , having bumps 124 ′ for electrically contacting cathode 20 a and forming air flow space 126 .
Embodiment 110 ′ differs from embodiment 110 in that electrical contact with plate 144 ′ and anode 18 b is provided by incorporation of metallic foam 36 or filaments 38 (not shown in FIG. 7 ) as in the prior art (FIG. 2 ), alternative to the bumps and dimples shown in first plate 122 in the first embodiment. Preferably, plate 144 ′ is canted as shown in FIG. 7 to progressively diminish the cross-sectional area of plenum 146 ′ in proportion to the reduction in mass flow through the plenum as a function of distance from the plenum entrance.
While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof 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 the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention include all embodiments falling within the scope and spirit of the appended claims.
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An improved system for more uniformly distributing gaseous fuel over the anode surface of a fuel cell, comprising an interconnect subassembly for electrically connecting anodes and cathodes of adjacent fuel cells in a fuel cell stack. The subassembly includes a perforated plate disposed adjacent the anode surface. The plate may be parallel to or inclined to the anode surface and forms a first wall of a fuel plenum for uniformly distributing fuel via the perforations over the entire surface of the anode. The second wall of the plenum is a plate separating the fuel flow from air flowing across the cathode. Electrical continuity across the interconnect subassembly may be provided, for example, by non-planar upsets such as bumps and dimples in the two plenum plate components, or by metallic foam or filaments disposed between the plates and the electrodes.
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CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 61/351,320 filed Jun. 4, 2010.
STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT
[0002] (Not Applicable)
REFERENCE TO AN APPENDIX
[0003] (Not Applicable)
BACKGROUND OF THE INVENTION
[0004] This invention relates generally to the field of scaffolding and more particularly to an adjustable scaffold base for allowing scaffold towers to be erected above ground level obstructions.
[0005] Traditionally, it has generally been difficult to change light bulbs or perform other high-elevation indoor maintenance tasks, such as painting or repairing ceiling surfaces, in churches, theaters, stadiums or other buildings that have high ceilings and that also have permanently-fixed ground level obstructions, such as pews or other fixed seating structures. Traditional frame-scaffolding that would normally be erected to facilitate high-elevation maintenance tasks is generally inappropriate for environments that include ground level obstructions because the spacing between the frame legs of such scaffolding typically does not match the spacing around pews or other large or irregularly-shaped obstructions. Even if the frame spacing of traditional scaffolding could be made to coincide with the spacing around ground level obstructions, the necessary cross-bracing between the scaffold frames would hit the obstructions. Furthermore, the legs supporting the scaffolding may have to bear on surfaces that can be 45 inches or more out of level with one another, whereas typical scaffolding leveling jacks that are normally employed to accommodate uneven surfaces only have about 14 inches of vertical adjustment. Still further, typical scaffold frames are only wide enough to support freestanding structures that are approximately 20 feet tall, which is not tall enough to reach the ceilings of many buildings.
[0006] It is possible for scaffold companies to build tube-and-clamp scaffolding structures that accommodate environments that present immovable, ground level obstructions, but the cost of labor and equipment to erect such structures is often prohibitively expensive. It would therefore be desirable to provide a relatively low-cost, highly adjustable scaffolding system that can be erected around immovable, ground level obstructions for accommodating high-elevation tasks such as replacing light bulbs and painting or repairing ceiling surfaces.
[0007] It is therefore an object and feature of the present invention to provide a low-cost means for allowing a conventional scaffold tower to be erected in a manner that avoids ground level obstructions. It is a further object and feature of the present invention to provide such a means that is suitable for supporting a conventional scaffold tower having a height that is sufficient for allowing a worker to reach the ceiling of a church or other such building having high ceilings. It is a further object and feature of the present invention to provide such a means that can be easily moved while still fully erected.
BRIEF SUMMARY OF THE INVENTION
[0008] In accordance with the present invention, there is provided an adjustable scaffold base for supporting a conventional scaffold tower at an elevated position above ground level obstructions. The scaffold base includes four elongated, upstanding primary legs that are spaced apart in a parallel relationship with one another. A first lateral beam extends between two of the primary legs in a perpendicular relationship therewith, and a second lateral beam extends between the other two of the primary legs in a perpendicular relationship therewith and in a parallel relationship with the other lateral beam. Each primary leg extends through a primary leg sleeve that is rigidly affixed to an adjacent end of the primary leg's respective lateral beam. Each primary leg sleeve can slidably move along its respective primary leg, thereby allowing each lateral beam to move up and down along the length of its respective pair of primary legs. Each primary leg sleeve can be removably secured at a plurality of positions along the length of its respective primary leg by extending a pin through a pair of axially-aligned positioning holes formed in the primary leg and its respective primary leg sleeve.
[0009] First and second frame beams extend across, and are removably secured to, the first and second lateral beams in a perpendicular relationship therewith and in a spaced, parallel relationship with one another. Each frame beam can be removably secured at a plurality of positions along the length of each lateral beam. A pair of frame posts extends upwardly from each of the frame beams in a perpendicular relationship therewith and in a spaced relationship with one another for engaging and rigidly supporting the scaffold frames of a conventional scaffold tower. A scaffold tower can thus be erected and supported atop the scaffold base, with the scaffold base straddling and avoiding ground level obstructions, such as church pews or other fixed, ground level structures.
[0010] The erected scaffold base and scaffold tower can be easily moved by inserting four auxiliary legs into vertically-oriented auxiliary leg sleeves that are rigidly affixed to the ends of the frame beams. Conventional casters are mounted to the bottom ends of the auxiliary legs. All of the auxiliary legs are lowered within their respective auxiliary leg sleeves until their casters are in contact with the surface upon which the scaffold base stands. The positions of the auxiliary legs are then secured by inserting pins through aligned pairs of positioning holes in the auxiliary leg sleeves and the auxiliary legs. Each of the primary legs is then raised within its primary leg sleeve and is secured at an elevated position, thereby leaving the scaffold base and the scaffold tower supported solely by the auxiliary legs and casters. The scaffold base can then be rolled upon the casters to a desired location, after which the primary legs can again be lowered and secured.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] FIG. 1 a is an exploded, perspective view illustrating the legs, feet, and lateral beams of the scaffold base present invention.
[0012] FIG. 1 b is a perspective view illustrating the assembled legs, feet, and lateral beams of the scaffold base of the present invention.
[0013] FIG. 2 a is a perspective view illustrating the assembled legs, feet, lateral beams, and frame beams of the scaffold base of the present invention.
[0014] FIG. 2 b is a detail view illustrating the mounting bracket of a frame beam of the present invention.
[0015] FIG. 3 a is a partially exploded perspective view illustrating the legs, feet, lateral beams, frame beams, and cross brace of the present invention.
[0016] FIG. 3 b is a perspective view illustrating the fully assembled scaffold base of the present invention.
[0017] FIG. 4 a is a front view illustrating the scaffold base of the present invention with the lateral beams mounted to the outsides of the mounting brackets of the frame beams.
[0018] FIG. 4 b is a front view illustrating the scaffold base of the present invention with the lateral beams mounted to the insides of the mounting brackets of the frame beams.
[0019] FIG. 5 is a perspective view illustrating a pair of scaffold frames mounted to the scaffold base of the present invention.
[0020] FIG. 6 is a perspective view illustrating a pair of cross braces mounted to the scaffold frames shown in FIG. 5 .
[0021] FIG. 7 is a perspective view illustrating a pair of guard rails and work platforms mounted to the scaffold frames shown in FIG. 6 .
[0022] FIG. 8 is a perspective view illustrating guardrail posts mounted to the scaffold frames shown in FIG. 7 .
[0023] FIG. 9 is a perspective view illustrating the scaffold base of the present invention with swivel plates mounted to the legs.
[0024] FIG. 10 is a perspective view illustrating the scaffold base of the present invention with leveling jacks mounted to the legs.
[0025] FIG. 11 is a perspective view illustrating the scaffold base of the present invention with auxiliary legs having casters mounted to the frame beams.
[0026] In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.
DETAILED DESCRIPTION OF THE INVENTION
[0027] This application claims the benefit of U.S. Provisional Application No. 61/351,320, which is incorporated herein by reference.
[0028] Referring to FIGS. 1 a - 4 b, an adjustable scaffold base for straddling ground level obstructions, such as church pews and other fixed structures, and supporting an upwardly-extending scaffold tower is indicated generally at 10 . The scaffold base 10 is defined by four feet 12 a - d, four primary legs 14 a - d, two lateral beams 16 and 18 , two frame beams 20 and 22 , and a cross brace 24 . Unless otherwise noted below, all of the components of the scaffold base 10 are fabricated from steel members and preferably square steel tubing members in particular. The use of any other suitable material, or combination of materials, such as aluminum, plastic and various composites, is contemplated and will be understood by the person having ordinary skill
[0029] For the sake of convenience and clarity, terms such as “top,” “bottom,” “up,” “down,” “inwardly,” “outwardly,” “lateral,” and “longitudinal” will be used herein to describe the relative placement and orientation of various components of the invention, all with respect to the geometry and orientation of the fully assembled scaffold base 10 as it appears in FIG. 3 b.
[0030] Referring to FIG. 1 a, each foot 12 a - d of the scaffold base is defined by a planar, preferably rectangular base plate 26 a - d, such as may be formed from wood or steel, with a tubular neck 28 a - d formed of a segment of round steel tubing rigidly affixed thereto in a perpendicular relationship therewith. Each foot 12 a - d is positioned on a support surface, such as the floor of a building, with the bottom of each base plate 26 a - d engaging the support surface and with the tubular neck 28 a - d of each foot 12 a - d extending upwardly therefrom. The support surface is typically an indoor flooring surface such as stone, brick, tile, or carpet, but could alternatively be soil, pavement or other outdoor surfaces. Of course, the flat base plates 26 a - d can be replaced by wheels or narrow legs.
[0031] Referring to FIG. 1 b, each lateral beam 16 and 18 of the scaffold base 10 is formed of an elongated segment of rectangular steel tubing that is preferably 7 feet, 9 inches in length, although it is contemplated that the lateral beams 16 and 18 can be made shorter or longer to suit various applications. Each lateral beam 16 and 18 has a series of positioning holes 30 formed through it that are spaced on 16 inch centers, wherein each positioning hole 30 provides a transverse, lateral passageway through its respective lateral beam 16 and 18 . An example of an acceptable diameter for each positioning hole 30 in the lateral beams 16 and 18 is 0.625 inches. The term “hole” is often used hereinafter to refer to a pair of axially aligned apertures, wherein one of the apertures is positioned on one sidewall of a hollow body, such as a tube, and the other aperture is positioned on the opposing sidewall. Each “hole” thereby provides a single passageway through the entire body, even though only one of the apertures of the hole is depicted in the illustrations. For example, only one of the apertures in each hole-pair is depicted in FIGS. 1 a and 1 b. The other apertures are on the opposite side of the structures but are impossible to show in an illustration of a three dimensional object.
[0032] Each lateral beam 16 and 18 terminates at each of its longitudinal ends in a primary leg sleeve 32 a - d that is formed of a short segment of square steel tubing that is rigidly connected to its respective lateral beam 16 and 18 , such as by welds, in a perpendicular relationship therewith. Each primary leg sleeve 32 a - d has positioning holes 34 formed through it that are spaced on 1.25 inch centers along the sleeve's length. Flat steel segments 36 a - d are preferably welded to the primary leg sleeves 32 a - d and to their respective lateral beams 16 and 18 for enhancing the strength and rigidity of the connections between the primary leg sleeves 32 a - d and the lateral beams 16 and 18 . Although incorporation of the leg sleeves 32 a - d is preferred, it is contemplated that the leg sleeves 32 a - d can be omitted and that the vertically-oriented holes can alternatively be formed through the lateral beams 16 and 18 for accepting the primary legs 14 a - d (as described below).
[0033] Referring to FIG. 1 a, each of the primary legs 14 a - d of the scaffold base 10 is formed of an elongated segment of square steel tubing that preferably measures 5 feet in length. It is contemplated that the primary legs 14 a - d can be made shorter or longer than 5 feet, and that one or more of the primary legs 14 a - d can have a length that is different than one or more of the other primary legs 14 a - d. Each primary leg 14 a - d has a series of groups of three positioning holes 38 formed through it, with the positioning holes 38 in each group being spaced on 2 inch centers and with each group spaced 8 inches apart, thus allowing ½ inch vertical adjustment of the primary legs 14 a - d. Referring to FIG. 1 b, each primary leg 14 a - d extends through, and axially engages, a primary leg sleeve 32 a - d of one of the lateral beams 16 and 18 (described above), with two of the primary legs 14 a - d thus mounted to each lateral beam 16 and 18 in a parallel relationship and at a fixed distance apart from one another. The exterior dimensions of the primary legs 14 a - d are slightly smaller than the interior dimensions of the primary leg sleeves 32 a - d in order that the primary leg sleeves 32 a - d may snugly receive the primary legs 14 a - d while allowing sliding axial movement of the primary leg sleeves 32 a - d, and therefore the lateral beams 16 and 18 , relative to the primary legs 14 a - d. Threaded stability bolts (not shown) preferably extend horizontally through a corner of each primary leg sleeve 32 a - d with the flats tips of the bolts engaging the primary legs 14 a - d within the sleeves. By tightening the bolts against the primary legs 14 a - d the primary legs 14 a - d can be stabilized against excessive lateral movement within their respective primary leg sleeves 32 a - d.
[0034] The bottommost ends of the primary legs 14 a - d fit over and axially engage the necks 28 a - d of the feet 12 a - d, thereby rigidly supporting the primary legs 14 a - d in a vertical orientation. Alternative embodiments of the scaffold base 10 are contemplated in which the primary legs 14 a - d are permanently mounted to the lateral beams 16 and 18 in a fixed position and are not slideably adjustable relative thereto.
[0035] In order to adjust the heights of the lateral beams 16 and 18 , such as to a height above fixed, ground level obstructions (described in greater detail below), the primary leg sleeves 32 a - d of each lateral beam 16 and 18 can be slid upwardly or downwardly along their respective primary legs 14 a - d. Since each lateral beam 16 and 18 is fixed at both of its longitudinal ends to a respective, vertically-oriented primary leg 14 a - d in a substantially perpendicular orientation therewith, the lateral beams 16 and 18 will remain in a substantially horizontal orientation as they are moved vertically along their respective primary leg-pairs. After each lateral beam 16 and 18 has been moved to a desired height at least one of the positioning holes 34 in each primary leg sleeve 32 a - d is brought into axial alignment with a closest positioning hole 38 in a respective primary leg 14 a - d. Pins 40 a - d are then inserted through each pair of aligned positioning holes 34 and 38 to secure the primary leg sleeves 32 a - d against vertical movement along the primary legs 14 a - d, thereby fixing the lateral beams 16 and 18 at the desired height. The pins 40 a - d are preferably standard, spring-loaded, positive locking pins having an outer diameter that is slightly smaller than the diameter of the respective holes through which they pass. However, all other types of fastening means, such as screws, bolts, rivets, clamps, non-spring-loaded pins, and friction mounts are also contemplated.
[0036] Referring to FIG. 2 a , the frame beams 20 and 22 are similar in construction and size to the lateral beams 16 and 18 , including auxiliary leg sleeves 42 a - d mounted to the longitudinal ends of the frame beams 20 and 22 that are substantially identical to the primary leg sleeves 32 a - d described above. Unlike the lateral beams 16 and 18 , the frame beams 20 and 22 do not have positioning holes formed in them. Each frame beam 20 and 22 includes a pair of frame posts 44 a - d formed of short segments of square steel tubing that are rigidly mounted to, and that extend upwardly from, the frame beams' top surfaces. The frame posts 44 a - d on each frame beam 20 and 22 are preferably spaced 5 feet apart from one another and are equidistant from the nearest longitudinal ends of their respective frame beam 20 and 22 , although it is contemplated that this spacing can be varied from the preferred distances.
[0037] A pair of positioning brackets 50 a - d is rigidly mounted to the underside of each frame beam 20 and 22 , with each positioning bracket 50 a - d positioned about 4.5 inches inward from a nearest longitudinal end of the frame beam 20 and 22 . The positioning brackets 50 a - d preferably measure 6 inches long and are formed of rectangular blocks of steel. Each positioning bracket 50 a - d has a 0.625 inch diameter positioning hole (not within view) extending horizontally through it for receiving a threaded bolt of a slightly smaller diameter (as described below), as best shown in FIG. 2 b.
[0038] When operatively positioned, the frame beams 20 and 22 rest on top of, and extend perpendicularly across, the lateral beams 16 and 18 , with each lateral beam 16 and 18 positioned inward of the auxiliary leg sleeves 42 a - d and outward of the positioning brackets 50 a - d of the frame beams 20 and 22 as best shown in FIGS. 2 a and 4 a . The frame beams 20 and 22 are preferably spaced 4 feet apart in a parallel relationship with one another, and with the positioning holes in the positioning brackets 50 a - d aligned with corresponding positioning holes 30 in the lateral beams 16 and 18 . Threaded bolts extend outwardly, through the positioning holes in the positioning brackets 50 a - d and through the positioning holes 30 in the lateral beams 16 and 18 . Nuts threadedly engage the outermost ends of the bolts, thereby securing the frame beams 20 and 22 to the lateral beams 16 and 18 . Configured thusly, the lateral beams 16 and 18 are spaced 7 feet apart. Alternatively, if the spacing between the lateral beams 16 and 18 must be less than 7 feet, such as for adjusting the spacing between the primary legs 14 a - d to avoid ground level obstructions, the lateral beams 16 and 18 can be secured to the innermost sides of the positioning brackets, as shown in FIG. 4 b . The threaded bolts extend inwardly through the positioning brackets 50 a - d and the lateral beams 16 and 18 and with the nuts engaging the innermost ends of the bolts, in which case the lateral beams 16 and 18 are spaced 6 feet apart. It is also possible to secure one of the lateral beams 16 and 18 to the outermost side of its corresponding positioning brackets 50 a - d and secure the other lateral beam 16 and 18 to the innermost side of its positioning brackets 50 a - d, in which case the lateral beams 16 and 18 are spaced 6 feet 6 inches apart. Alternative embodiments of the scaffold base are contemplated wherein the positioning brackets 50 a - d are omitted and the frame beams 20 and 22 are rigidly connected to the lateral beams 16 and 18 in a fixed position, such as by welds or conventional fasteners.
[0039] Referring to FIGS. 3 a and 3 b , the cross brace 24 is formed of two elongated segments of steel angle that are fastened together in a perpendicular relationship, such as with a rivet, to form an X-shaped member. The cross brace spans across, and is rigidly fastened to, the undersides of the frame beams 20 and 22 , such as with conventional nut-bolt combinations that engage apertures formed through the cross brace 24 and the frame beams 20 and 22 , for providing the scaffold base 10 with added strength and rigidity. It is contemplated that the cross brace 24 can be rigidly fastened to the frame beams 20 and 22 in any other suitable manner. It is further contemplated that the cross brace 24 can be omitted or that other bracing means, such as additional lateral or longitudinal frame members installed intermediate the frame beams 20 and 22 and the lateral beams 16 and 18 , can additionally or alternatively be incorporated into the scaffold base 10 .
[0040] Referring to FIG. 5 , once the scaffold base 10 has been erected at a desired location and the lateral beams 16 and 18 have been adjusted to a desired height, such as above the height of ground level obstructions that would prevent the erection of traditional scaffold towers, conventional scaffold frames 60 and 62 can be connected to the elevated frame beams 20 and 22 . Particularly, elongated stack pins (not shown) that extend from, and are rigidly connected to, the uppermost ends of the vertical members of the scaffold frames 60 and 62 axially engage the frame posts 44 a - d and are securely held therein in a vertical orientation. The scaffold frames 60 and 62 thereby span across the frame beams 20 and 22 and are secured in a vertical orientation and in a parallel relationship with one another. Referring to FIG. 6 , the scaffold frames 60 and 62 are preferably secured to one another with conventional cross braces 64 and 66 . Finally, referring to FIG. 7 , conventional guardrails 68 and 70 and aluminum work platforms 72 and 74 are secured to the scaffold frames 60 and 62 to complete the scaffold tower 76 . If more height is required, additional frame members and guardrails can be added to the scaffold frames 60 and 62 in a conventional manner and the work platforms 72 and 74 can be secured at a higher position on the scaffold tower 76 , as shown in FIG. 8 . During testing it has been demonstrated that the scaffold base 10 is capable of stably supporting free-standing scaffold structures measuring over 150 feet in overall height.
[0041] If the scaffold base 10 must be positioned on a sloped surface, such as on an auditorium aisle way or on a wheelchair ramp, it is contemplated that conventional swivel plates 80 a - d can be substituted for one or more of the feet 12 a - d, as shown in FIG. 9 , for allowing the primary legs 14 a - d to extend vertically from the sloped surface. It is further contemplated that one or more of feet 12 a - d can be replaced by screw-threaded leveling jacks 82 a - d, as shown in FIG. 10 , for allowing the heights of the primary legs 14 a - d to be finely adjusted and leveled to optimize the stability of a scaffold tower erected thereon. Those skilled in the art will recognize that various other mounting accessories can be substituted for one or more of the feet 12 a - d without departing from the spirit of the invention.
[0042] Referring to FIG. 11 , the erected scaffold base 10 and tower can be conveniently moved through the use of auxiliary legs 90 a - d that are fitted with casters 92 a - d. This is accomplished by inserting the auxiliary legs 90 a - d into the auxiliary leg sleeves 42 a - d (described above) of the frame beams 20 and 22 from above, after which conventional scaffold casters 92 a - d are mounted to the bottom ends of the auxiliary legs 90 a - d. The auxiliary legs 90 a - d engage the auxiliary leg sleeves 42 a - d of the frame beams 20 and 22 in a substantially identical manner to the engagement between the primary legs 14 a - d and the primary leg sleeves 32 a - d of the lateral beams 16 and 18 described above. The height of each auxiliary leg 90 a - d relative to its respective auxiliary leg sleeve 42 a - d can similarly be adjusted and secured by sliding the auxiliary legs 90 a - d vertically within their respective auxiliary leg sleeves 42 a - d to a desired height and inserting pins through aligned pairs of positioning holes in the auxiliary leg sleeves 42 a - d and the auxiliary legs 90 a - d. It is contemplated that the primary legs 14 a - d can also be fitted with castors for further improving the mobility of the scaffold base 10 .
[0043] To move the scaffold base 10 , all of the auxiliary legs 90 a - d are lowered until their respective casters 92 a - d are in contact with, or are nearly in contact with, the surface upon which the feet 12 a - d of the scaffold base 10 rest. The vertical positions of the auxiliary legs 90 a - d are then secured. Each of the primary legs 14 a - d is then raised within its primary leg sleeve 32 a - d and is secured at an elevated position, thereby leaving the scaffold base 10 and the scaffold tower supported solely by the auxiliary legs 90 a - d and casters 92 a - d. Alternatively, the primary legs 14 a - d can be entirely removed from their respective primary leg sleeves 32 a - d (which requires removal of the feet after the primary legs 14 a - d have been raised a short distance off the support surface). The scaffold base 10 can then be rolled upon the casters 92 a - d to a desired location. Since the auxiliary legs 90 a - d are spaced only four feet apart from one another, the scaffold base 10 can easily fit through most aisle ways and other narrow areas while the elevated lateral beams 16 and 18 and primary leg sleeves 32 a - d move above ground level obstructions (i.e., if the primary legs 14 a - d have been entirely removed from, or sufficiently raised in, the scaffold base 10 ). Once the scaffold base 10 has been moved to a desired location, the primary legs 14 a - d and feet can be reinstalled and repositioned to support the scaffold base 10 in the manner described above, and the auxiliary legs 90 a - d and casters 92 a - d can be raised or entirely removed from the scaffold base 10 .
[0044] This detailed description in connection with the drawings is intended principally as a description of the presently preferred embodiments of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the designs, functions, means, and methods of implementing the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and features may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention and that various modifications may be adopted without departing from the invention or scope of the following claims.
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An adjustable scaffold base for straddling ground level obstructions, such as church pews and other fixed, ground level structures, and supporting an upwardly-extending scaffold tower thereon. The scaffold base incorporates four legs and four elevated, height-adjustable cross beams that allow a scaffold tower to be erected above the height of many fixed, ground level structures. The erected base and tower thereby allow workers to access elevated areas within high-ceilinged buildings, such for performing ceiling repairs, painting, and changing light bulbs.
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BACKGROUND OF THE INVENTION
The present invention relates to a method of and circuit for digitally demodulating an amplitude-modulated signal, produced by suppressed-carrier amplitude modulation of two carriers of the same frequencies in a phase-quadrature relationship, provided with a circuit for determining the square a 2 of the peak amplitude a of a sinusoidal reference signal which is in synchronism with the modulated signal and with sampling means; it also relates to the use of such a method in, for example, an embodiment of a demodulation stage for the chrominance signal of a video-frequency signal of a television receiver and actually to any television receiver comprising such a demodulation stage.
The French Patent Application No. 8218254 filed by Applicants on Oct. 29th, 1982, describes a demodulation circuit in which measures are taken to recover, from the modulated signal, on the one hand, a first digital signal which is proportional to the frequency of the modulated signal, and, on the other hand, a second digital signal which is proportional to the square of the peak amplitude of the modulated signal.
It is necessary to describe briefly the demodulation procedure used to determine the frequency and the square of the peak amplitude of the modulated signal described in said patent application.
If the general expression of the analog input signal is of the type x=a·sin ωt, the digital signals at the outputs of the first and second registers 20, 21 and of the analog-to-digital converter 10 have the respective expressions, at a constant sampling frequency (Fe=1/T):
x.sub.n =a·sin ωt.sub.n for t=t.sub.n ( 1)
x.sub.n+1 =a·sin (ωt.sub.n +φ) for t=t.sub.n +T (2)
x.sub.n+2 =a·sin (ωt.sub.n +2 φ) for t=t.sub.n +2T (3)
From these three consecutive measurements x n , x n+1 , x n+2 , it is possible to express the cosine of the angular phase shift φ by: ##EQU2##
As it is obvious that the phase shift φ is equal to ##EQU3## wherein Fe is the chosen, constant sampling frequency, Fs is the frequency of the modulated signal ##EQU4## it is obtained that: ##EQU5## which renders it possible to determine the frequency of the input signal and, for example, to demodulate the chrominance signal, which, for the SECAM system, is frequency-modulated.
In a similar way, it is possible to express, from three identical consecutive measurements, the square of the amplitude a of the signal by the following expressions, which can be easily derived from the expressions (1) to (3) by simple trigonometrical manipulations: ##EQU6## This can be expressed by the general formula: ##EQU7##
On the other hand, French Patent Specification No. 2,502,423, which corresponds to the French Patent Application No. 815,285, on Mar. 17th 1981, describes a demodulator for demodulating digital frequency-modulated or amplitude-modulated chrominance signals obtained by amplitude modulation with suppressed carrier of two quadrature-phase carriers. The specification describes a demodulation method based on a representation of the frequency-modulated or amplitude-modulated signal by a vector turning in a plane OXY, said signal being sampled by a signal having a frequency 4F, that is to say four times higher than:
either the center frequency of the frequency band for the case of frequency modulation (SECAM);
or the carrier frequency in the case of amplitude modulation (PAL).
For the case of amplitude modulation of the PAL type, which is of interest for the present case, the demodulation procedure is limited to sampling the modulated signal by a signal having a frequency 4F, the case of amplitude modulation being converted to that of frequency modulation where simplifications become apparent connected with approximations relative to the frequency deviations.
SUMMARY OF THE INVENTION
The invention has for its object to provide a method and a digital demodulation circuit as defined in the opening paragraph, which are characterized in that the rate of the reference signals and the rate of the modulated signals may be synchronous or asynchronous, which rate may occur over a wide frequency range, it being possible to put the method into effect using simple algebraic expressions.
To this effect, the invention relates to a digital demodulation method of a signal of the type:
m.sub.p+1 =u·cos (α+kφ)+v·sin (α+kφ) p and k integers
characterized in that it comprises the following steps:
determining and thereafter storing the sign of the reference signal x n+m and the sign of the derivative of said reference signal,at a predetermined instant t n+m for which k is given the value zero;
determining at the instant t n+m the square of the sine of the initial angular phase shift, denoted as the real angular phase shift α r , or the inverse of this square in accordance with the expression 1/sin 2 α r =a 2 /x 2 n+m ;
determining the values of sin α r , thereafter a value α t corresponding to one of the values of arc sin α r chosen in one of the four quadrants of a customary trigonometrical presentation;
determining the value of the real angular phase shift α r from the value of α T , knowledge of the selected quadrant, and the signs of the reference signal and of the derivative of said reference signal for the same instant t n+m ;
determining and thereafter storing, sequentially, at each instant of the sampling rate, the values α r +kφ modulo 2π;
determining and storing, sequentially, the pairs of values sin (α r +kφ) and cos (α r +kφ), sin (α r +(k-1)φ) and cos (α r +(k-1)φ) for two consecutive instants of the rate; and
determining values which are proportional to the modulating signals u and v, from two samples m p and m p+1 of the modulated signal, by :
m.sub.p ·sin (α.sub.r +kφ)-m.sub.p+1 ·sin (α.sub.r +(k-1)φ) proportional to u
and
m.sub.p+1 ·cos (α.sub.r +(k-1)φ)-m.sub.p ·cos (α.sub.r +kφ) proportional to v.
DESCRIPTION OF THE DRAWINGS
Particulars and advantages of the invention will become apparent from the following description which is given by way of non-limitative example with reference to the accompanying drawings, in which:
FIG. 1a shows a first circuit 11 for determining the square a 2 of the peak amplitude a in accordance with the prior art method and a third circuit 13 for determining the value of the real angular phase shift according to the invention;
FIG. 1b shows a second circuit 12 for calculating the derivative of the reference signal and the sign, the values of 1/x 2 n+m , the sign of the reference signal of its derivative;
FIG. 1c shows a fourth circuit 14 for calculating the values α r +kφ at the beginning of each rate period, and the values sin (α r +kφ) and cos (α r +kφ)for two consecutive rate instants;
FIG. 1d shows a fifth circuit 15 for calculating the in-phase and quadrature components of said modulation signal; and
FIG. 2 shows an input multiplexing circuit of the calculating arrangement 62 in accordance with a further embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The method and the digital amplitude demodulation circuit according to the invention can process, in a preferred embodiment, the chrominance information components in accordance with the PAL system. To that end, the processing in the time of the television line is divided sequentially in a processing of the burst, used here as a reference, and thereafter in a processing operation on that portion of the line which comprises the chrominance information components, used here as the modulated signal to be analyzed.
The processing operation on the burst has for its object to determine, in each line, the data about the amplitude and the phase used during the subsequent processing of the chrominance information components.
The burst is a pure sinusoidal wave having a perfectly stabilized frequency and which can be represented by x=a·sin ωt wherein ω=2πFs, Fs being the burst frequency. This signal is sampled by a signal having a frequency Fe.
Samples x n+2 , x n+1 , x n respectively, such as:
x.sub.n =a sin (ωt.sub.n), x.sub.n+1 =a sin (ωt.sub.n +φ), x.sub.n+2 =a sin (ωt.sub.n +2 φ),
become available at the outputs of the analog-to-digital converter 10, the first register 20 and the second register 21. It will be obvious that the angular phase shift between the burst and the rate signal is equal to ##EQU8## In accordance with the known method, by performing the calculation for the expression (6), it is possible to determine the square of the peak amplitude of the burst signal.
In the known PAL television system, the burst frequency is perfectly constant. By operating with a constant rate frequency, the angular phase shift φ is constant and perfectly determined. This also holds for sin 2 φ which is used as a constant in the calculation of a 2 . This calculation is effected in accordance with the method known from the above-mentioned patent application filed by Applicants, in which the second calculating arrangement 23, is, for example, a digital multiplier and the first calculation arrangement 22 is a memory in which all the already precalculated results of x n+1 2 are stored. The third calculating arrangement 24, is, for example, a subtractor, or an adder when the digital data are shown in a two's complement representation. The fifth calculation arrangement 32 receives at one input the result of the operation x n+1 2 -x n ·x n+2 and at the other input a defined digital value representing 1/sin 2 φ, for the case in which the fifth calculation arrangement 32 is a multiplier. This digital value would represent sin 2 φ when the fifth calculating arrangement 32 were a divider. In both cases the value of a 2 is obtained as it is defined by the equation (6). This is already described in the abovementioned Applicants Patent Application.
For the case in which the frequency of the modulated signal or that of the sampling rate are not really constant, the fourth calculation arrangement 31 renders it possible to effect the calculation of 1/sin 2 φ or sin 2 φ from previous measurements of a parameter connected with the angular phase shift, for example cos φ. This calculating arrangement may be omitted when these two frequencies are perfectly constant, in which case the value of 1/sin 2 φ or of sin 2 φ is directly entered into the fifth calculating arrangement 32.
The particulars and advantages of the invention will now become apparent from the following description.
The digital data, for example those from the output of the second register 21, are applied to the subcircuit 49 (FIG. 1b), which determines the derived of the input signal, for example, by means of a known digital filtering operation as, for example, described in Applicants Patent Application No. 8112412, filed June 24th 1981, The sixth calculating arrangement 44 employs the data x n+m+i to x n+m-j of a series of i+j1 registers, for example those from a third register 41 to a fifth register 43. Consequently, the information x n+m , the j preceding data and the subsequent i data are then stored around an instant t n+m . By weighting each information component with a coefficient, the derivative is calculated in accordance with a general expression of the type: ##EQU9## Advantageously, this digital filter 49 will have an odd number (i=j) of registers to ensure that the calculation of the derivative will be determined for a rate instant during which the data x n+m is stored in the fourth register 42. An even digital filter (i≠j) may alternatively be used, but with an adapted rate. Similarly, the digital filter 44 would use advantageously coefficients a p equal to integral powers of 2 so as to effect the calculation in accordance with equation (9) by simple shifts of the digital data. As the sole object is to preserve the sign of this derivative, the structure of the filter 44 is only determined by the fact that the correct sign must be obtained, the digital value itself is of no importance. Thus, a filter having, for example, 3 registers has proved to be satisfactory for shifting the data for the calculation operation. The sign of this derived and the sign of the sample x n+m corresponding therewith are preserved in a memory device 45 for later use.
The digital values of x n+m are entered in a seventh calculating arrangement 46, which supplies at its outputs the corresponding values 1/x 2 n+m . Advantageously, this seventh calculating arrangement 46 is constituted by a memory device in which the values which were already precalculated are stored.
Thus, the signal cc for the values of 1/x 2 n+m and signals dd and qq for said two signs are available at the output of the second circuit 12. After the determination of a 2 has been effected, this second circuit 12 is operative at the instant near the ends of the burst but before the chrominance information components of the line begin to appear. This instant is defined by the operating speed of the arrangements used.
The signal cc is entered into the eighth calculating arrangement 50 (FIG. 1a), which is constituted by, for example, a multiplier, which calculates 1/sin 2 α r in accordance with:
1/sin.sup.2 α.sub.r =a.sup.2 /x.sup.2.sub.n+m (10)
By means of the ninth calculating arrangement 51, it is possible to determine from the values of 1/sin 2 α r , the values denoted by α T and defined by α T =arc sin α calculated in, for example, the first quadrant (0, π/2) of a customary trigonometrical presentation. The determination of the values of α r is effected in the tenth calculating arrangement 52, taking into consideration the signs of the derivative and of the signal for the same sample as that processed in expression (10) in accordance with the following Table:
______________________________________ sign of the sign of the calculations signal derived effected______________________________________1st quadrant + + α.sub.r = α.sub.T2nd quadrant + - α.sub.r = π - α.sub.T3rd quadrant - - α.sub.r = π + α.sub.T4th quadrant - + α.sub.r = 2π - α.sub.T______________________________________
If α T is calculated in an other quadrant, so shifted through π/2, π or ##EQU10## it is necessary to take this into account to effect the calculations of the Table in a manner which will be obvious for a person skilled in the art.
The value of α r is obtained at the output of the tenth calculating arrangement 52 (signal rr). This value α r is introduced in the fourth circuit 14 (FIG. 1c) which, for each selected rate period, increments the value α r by the value ##EQU11## thereafter the values thus obtained in accordance with the equation: ##EQU12## and thereafter compares this value, each time, with the value 2π, and, if necessary, effects subtraction of the value 2π so as to maintain the value of α r in the interval (0.2π).
For that purpose the fourth circuit 14 is formed by:
(a) a first input multiplexer 80 which selects the value of α r supplied by the tenth calculating arrangement 52, thereafter the consecutive values α r +kφ supplied by the twelfth calculating arrangement 83;
(b) an eleventh calculating arrangement 81 which receives at its first input the output value of the first multiplexer 80 and at its second input a digital representation of the angular phase shift ##EQU13##
(c) a sixth register 82 intended to divide over two consecutive periods of time of said selected rate the operation of the closed-loop circuit formed by the first multiplexer 80, the eleventh calculating arrangement 81, the twelfth calculating arrangement 83 and said sixth register 82;
(d) a digital comparator 84 effecting the comparison between the output of the sixth register 82 and a digital representation of the constant 2π;
(e) a twelfth calculating arrangement 83 effecting the subtraction of a digital representation of the constant 2π, when the comparator 84 detects that the result present at the output of the sixth register 82 exceeds the constant 2π.
The seventh and eight registers 90 and 91 preserve the calculated values during one rate period, this being necessary for the alternating operation of the calculating arrangements described hereinafter. The fourth calculating arrangement 93, for example a memory in which a precalculated Table is stored, supplies for each rate period the value sin (α r +kφ)| signal f|, whose preceding value sin (α r +(k-1)φ)| signal e| appears at the output of the tenth register 95. Similarly, the signal h corresponds to the value cos (α r +kφ) and the signal g corresponds to the value cos (α r +(k-1)φ) produced by the thirteenth calculating arrangement 92 and the ninth register 94, respectively.
When now in account is taken of the fact that the representation of the two signals which modulate two sub-carriers which have the same frequencies but are in a phase quadrature relationship is:
m.sub.p =u·cos (α.sub.r +(k-1)+v sin (α.sub.r +(k-1)φ) (11)
the subsequent sample will be represented by:
m.sub.p+1 =u·cos (α.sub.r +kφ)+v sin (α.sub.r +kφ). (12)
Denoting:
e=sin (α.sub.r +(k-1)φ)f=sin (α.sub.r +kφ)
g=cos (α.sub.r +(k-1)h=cos (α.sub.r +kφ)
it is easy to see that: ##EQU14## It can also be demonstrated that g·f-h·e=sin φ. This value is a constant when the amplitude of one or a plurality of subcarriers having a constant frequency is modulated. It can be derived that the components u and v are proportional to, respectively, m p ·f-m p+1 ·e and m p+1 ·g-m p ·h. In an experimental embodiment, the calculation precision, i.e. the number of binary elements which constitute the data, must be adapted to the value of sin φ.
The samples m p (equation 11) supplied by the first circuit 11, for example from the output of the first register 20 (signal bb), is entered into the delay device 60 of the fifth circuit 15 (FIG. 1d), while the samples m p+1 (equation 12) supplied by said first circuit 11 shifted through one rate period with respect to the sample m p , for example, taken from the output of the second register 21 (signal aa) is entered into the fifth circuit 15 in a further delay device which is identical to the delay device 60. These devices ensure phase agreement between the information components arriving in the fifteenth and eighteenth calculating arrangements 62 and 70. The second multiplexer 61 receives the two results f and h and the fifteenth calculating arrangement 62 determines, alternatively, during, each of the two rate periods, the values of the products m p ·h and m p ·f storing each, for each of said two periods, in the eleventh register 63 and the twelfth register 64. In an identical way the seventh circuit 17 supplied the results of the calculations of the products m p+1 ·g and m p+1 ·e. The phase and rate are defined in such a way that the sixteenth calculating arrangement 65, for example a subtractor, effects the operation m p+1 ·g-m p ·h. The results obtained after each sampling instant are stored for the whole duration of a line of the chrominance information and preserved during the subsequent line in the first storage and calculating circuit 66, which also effects the processing of said two consecutive lines in accordance with the customary principles of processing a signal in accordance with the PAL system.
The seventeenth calculating arrangement 67 effects a processing operation which is similar to that of the sixteenth calculating arrangement 65 but does so on the samples m p ·f and m p+1 ·e for the other rate phase. The results obtained at the end of the subtracting operation m p ·f-m p+1 ·e are stored in the second storage and calculating circuit 68.
At the output of the fifth circuit 15, the two inphase components u and v are obtained at a rate which is, for example, half the rate of the fifth calculating arrangement 62.
The sampling operation can be effected over a very large frequency range. It is known that the lower limit of the sampling frequency is defined such that one has at least 2 samples available in each period of the signal to be analyzed for the highest frequency of said signal to be analyzed. For a correct sampling of the subcarrier itself, the lower limit will consequently be Fe≧2·(F carr ) max . When only said modulating signal is desired, the lower limit will be Fe≧2 (F mod ) max , which is, for example, effected in accordance with the equation (8). This second, less restrictive limitation must nevertheless be high, taking into account the desired resolution, consequently the number of samples, for the correct recovery of said modulating signal.
Without departing from the object of the invention, different variants of the description given in the foregoing can be conceived. More specifically, it is advantageous to arrange that, for example, the fifteenth calculating arrangement 62 (FIG. 2) effects the calculations of the second calculation arrangement 23, the fifth calculation arrangement 32 and the eight calculation arrangement 50 by means of a more extensive multiplexing of said fifteenth calculation arrangement 62. Thus, the third multiplexer 61a receives:
the signal 100 representing x n+2
the signal 101 representing m p
the signal 102 representing 1/sin 100 2
the signal 103 originating from the output of the register 110.
Similarly, the fourth multiplexer 61b receives:
the signal 105 representing x n
the signal 106 representing f
the signal 107 representing h
the signal 108 originating from the third calculating arrangement 24.
The register 110 preserves the results of calculating a 2 for later usage.
It is even possible to multiplex the fifteenth calculating arrangement 62 and the eighteenth calculating arrangement 70 differently for different operations to be effected without departing from the object of the invention.
It should be noted that the invention not only applies to the demodulation of a PAL chrominance signal, but that it may alternatively be used to demodulate any signal obtained by means of amplitude modulation with suppressed sub-carrier, of two sub-carriers of the same frequency and in a phase-quadrature relationship and comprising a synchronous sinusoidal reference signal.
Similarly, by a more extensive multiplexing of the fifteenth calculating arrangement 62 and/or of the eighteenth calculating arrangement 70, the frequency and amplitude demodulation of a frequency-modulated signal, for example the chrominance signal of the SECAM type, is effected in accorance with the known method represented by the equations (4) and (6). Thus, one has the disposal of a television receiver by means of which it is possible to demodulate the chrominance information components in accordance with, optionally, the PAL and/or SECAM system.
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The invention relates to a method of and a circuit for digitally demodulating a suppressed-carrier amplitude-modulated signal, of two carriers having the same frequencies Fs in a phase-quadrature relationship, and having a sinusoidal reference signal which is in synchronism with said modulated signal. The method consists in determining the initial angular phase shift α r , between the reference signal and the sampling signal of the frequency Fe by determining the peak amplitude, as well as the sign of the reference signal and the sign of its derivative for a given sampling instant t n+m . The successive values α r +kφ of the angular phase shifts relative to said modulated signal are thereafter determined by successively adding the phase shift ##EQU1## The amplitudes of the modulated signal of the two quadrature sub-carriers are determined with the aid of tables containing the values of cos (α r +kφ) and sin (α r +kφ).
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BACKGROUND OF THE INVENTION
This invention relates to utility cover extensions and more particularly to utility cover extensions for adjusting the level of a utility cover to a new grade.
In the repair and resurfacing of streets and highways, it is frequently found that the repaired or resurfaced roadway is substantially higher than the original roadway. Accordingly, the top surface of the utility covers in the roadway, such as manhole covers, water and gas valve covers, gas and water meter covers and the like, are disposed substantially below the new road surface. This lower position of the utility cover creates a hazardous driving condition. These utility covers must be raised in order to adjust their top surfaces to that of the new level of the roadway.
In the original roadway, the utility cover is positioned over an access opening of a utility housing. The access opening generally has a support flange on which the utility cover is supported with the top surface of the utility cover to the level as the original highway.
One known construction for raising a utility cover to the new grade of the repaired or resurfaced roadway are manhole cover supports used to raise a manhole cover above the manhole housing so that the top of the manhole cover is at the new grade of the roadway. These manhole cover supports are designed to fit into the manhole housing and support the cover so that its top surface is at the new level of the roadway. The use of such manhole cover supports are desirable since it becomes unnecessary to replace the frame which is embedded in a paved road.
When raising the utility cover to a new grade, it is desirable to provide a utility cover support which when assembled with the utility frame and cover resists displacement or dislocation of those components under normal service conditions of the roadway. Under such service conditions various vehicle traffic loadings occur including axle, wheel and impact loadings, and various temperature conditions, such as steam from steam lines, and various chemical conditions, for example, spills of oil or gasoline on the roadway, also occur. If such service conditions create displacement or dislocation of the utility cover extension, utility housing, or cover, a depression or protrusion in the road surface will be realized which creates a driving hazard.
Furthermore, other hazardous driving conditions may be created, for example, when a impact loading is made on one of the components, such as the cover, and the cover pops out of the opening. Accordingly, it is desirable that relative movement between the components be resisted under such service conditions which includes the ability to absorb impact loadings, operate under various temperature conditions and various chemical environments.
It is also desirable to provide a utility cover support which resists rotation of the utility cover which results in wear between the components. For example, after repeatedly impacting the utility cover on one side, the cover tends to rotate thus abrading the surfaces between the cover and the utility support. Such wear creates a looser fit and allows more movement between the cover and the cover support. As the surfaces between the utility cover and utility cover support wear, the likelihood of displacement or dislocation of the cover under normal service conditions is increased which accordingly creates a hazardous driving condition.
It is also desirable to minimize the flow of surface water and other contaminants into the access opening of the utility housing. Water infiltration into the access opening of the utility housing has been a continuous problem with telephone companies, municipal public work departments and other public utility companies. For example, it is desirable to segregate different types of municipal water systems. Large volumes of additional waste water must be treated when surface water infiltrates into a sewer system through a manhole. The overloading of sewage systems has increased in importance from many years ago and the key factor is that today there is significantly less pervious area than there was years ago. This factor is due to larger impervious street surfaces that collect more drainage water as well as smaller building lot sizes which cut down on the amount of overall pervious area. By significantly decreasing the flow of storm and drainage water into the access opening, existing water treatment facilities can handle more sewage capacity.
In the case of electric and gas underground systems, in many instances, continuous pumping of water is required before utility men can enter a manhole because of water infiltration between the manhole cover components. In the case of utility cover assemblies for utility valves, meters and the like, the surface water and other contaminants such as dirt, deteriorate the valve or meter and inhibit its operation and ease of access thereto. It is also desirable to keep contaminants out of the utility frame in the case of gas and water meters to allow for ready access to the gas and water meters and reading thereof and their operation.
It is desirable to provide a utility cover support which reduces noise generated under normal service conditions. It is also desirable to absorb and dissipate the energy exerted on the components of the utility cover support assembly under normal service conditions.
SUMMARY OF THE INVENTION
The present invention provides the above described desireable features with an improved utility cover extension. The utility cover extension of the present invention is provided to be inserted into the access opening of a utility housing for vertically adjusting the level of a utility cover over the access opening to a new grade. The access opening of the utility housing includes a support flange with an upwardly and outwardly sloping peripheral surface extending from the flange. The utility cover has a bottom and an outer peripheral surface extending therefrom. The extension has an assembled and an unassembled condition with the utility cover and housing.
The extension has a bottom portion for insertion into the access opening of the utility housing and an upper portion for receiving the utility cover therein The bottom portion has a bottom support surface positionable adjacent the support flange of the utility housing and a bottom outer peripheral surface extending upwardly from the bottom support surface and upwardly sloping peripheral surface of the utility housing when in an assembled condition.
The upper portion has an upper support surface for supporting the utility cover and an upper inner peripheral surface extending upwardly from the upper support surface and positionable adjacent to and complimentary with the outer peripheral surface of the cover when in the assembled condition. The utility extension includes an extension frame and a compressible material forming at least a portion of the peripheral surfaces of the extension housing. The peripheral surfaces of the extension have a circumference with an interference fit with its complimentary peripheral surface of the utility housing and cover. In an assembled condition, the compressible material is compressed and frictionally engages under compression the utility cover and the utility housing and provides a sealing relationship therebetween.
The present invention provides methods for improving the frictional engagement of a utility cover extension to a utility housing or a utility cover. The present invention also provides methods for improving the seal between the utility cover extension and a utility housing or cover.
The present invention achieves the desired feature of resisting the premature displacement or dislocation of the utility cover extension assembly by increasing the frictional forces between the components of a utility cover extension assembly. By forming the peripheral surfaces of the utility cover extension from a flexible compressible material, the forces exerted on the assembly are absorbed and dissipated and the components of the assembly urged to return to their original position.
In an unassembled condition, and when the cover extension is at its assembled circumferential condition, the complimentary peripheral surfaces of the utility housing, extension and cover have an interference fit. The circumference of the outer peripheral surface of the lower portion of the extension is greater than the circumference of the inner peripheral surface of the utility housing. The upper inner peripheral surface of the upper portion of the utility cover extension is less than the circumference of the utility cover. When the utility cover extension is assembled with the housing, the compressible material is compressed and deforms to the above mentioned circumference of the inner peripheral surface of the frame. When the cover is assembled with the utility cover extension the inner peripheral surface of the upper portion of the extension is deformed and the compressible material compressed to the configuration of the circumference of outer peripheral surface of the cover. In such an assembled relationship the cover assembly provides for the resilient frictional interconnection of the components of the utility cover extension assembly while allowing for resilient movement of the components therebetween to absorb and dissipate impact forces experienced in normal service conditions without losing frictional engagement of the components.
The present invention also provides the desirable feature of resisting infiltration of surface water and other contaminants into the access opening. The compressible material provides for sealing the complimentary peripheral surfaces between the cover and cover extension and also between the cover extension and the frame. This seal is maintained even with slight relative movement of parts of the cover extension assembly since the compressible material flexes and maintains a seal during such movement. In the case of an adjustable cover support, the compressible material is sufficiently flexible to fill the spaces between the segments of the rigid portion of the cover support and maintain continuous contact about the entire periphery of the complimentary peripheral surfaces.
Utility cover extensions of the present invention may have a wide variety of constructions and designs. For example, manhole cover supports may be of solid continuous construction, as cast rings, or adjustable to fit various manhole housing openings. The geometric configurations of utility cover supports may be of a variety of configurations for example, round, square, rectangular or triangular shapes dependent on the shape of the utility housing and frame and may be manufactured by forming, fabricating or casting.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one embodiment of a cover extension of this invention assembled for use in the top of a utility housing;
FIG. 2 is a cross-sectional view of the utility cover extension shown in FIG. 1 and taken along line 2--2 of FIG. 1 when the cover is in an unassembled condition;
FIG. 3 is a fragmentary sectional view of the cover extension and housing shown in FIG. 1 and taken along line 2--2 of FIG. 1;
FIG. 4 is sectional view of the cover extension and housing taken line 2--2 of FIG. 1 with a cover assembled therewith;
FIG. 5 is an exploded perspective view of another embodiment of a cover extension of the present invention mounted in a utility cover housing;
FIG. 6 is a sectional view of the cover extension shown in FIG. 5 and taken along line 6--6 thereof in an unmounted condition;
FIG. 7 is a cross-sectional view of the cover extension and housing shown in FIG. 5 in assembled condition taken along line 6--6 thereof;
FIG. 8 is a sectional view of the extension and housing shown in FIG. 7 with a cover assembled therewith;
FIG. 9 is a sectional view of yet another embodiment of the cover extension of the present invention when in an unassembled condition;
FIG. 10 is a cross-sectional view cover extension shown in FIG. 9 when assembled with a housing;
FIG. 11 is a cross-sectional view of the cover extension shown in FIG. 10 when assembled with a cover;
FIG 12 is a sectional view of a further embodiment of the cover extension of the present invention when in an unassembled condition;
FIG. 13 is a cross-sectional view of the cover extension shown in FIG. 12 when assembled with a utility housing and cover;
FIG. 14 is a cross-sectional view of the cover extension shown in FIG. 13 taken through the adjustable portion of the cover extension;
DETAILED DESCRIPTION OF THE INVENTION
Referring now more specifically to the drawings, a utility cover extension 10 embodying the features of the present invention is shown in FIGS. 1-4. The utility cover extension 10 is provided for insertion into a utility housing 12 having an access opening 14 therethrough. The utility cover extension 10 is provided for vertically adjusting to a new grade the level of the utility cover 16 over the access opening 14 of the housing 12. The access opening 14 includes a support flange 18 with an upwardly sloping peripheral surface 20 extending therefrom. The utility cover 16 has a bottom 22 and an outer peripheral surface 24 extending therefrom.
The extension 10 has an unassembled condition shown in FIG. 2 and an assembled condition shown in FIG. 4. In the assembled condition, the extension 10, housing 12, and cover 16 form the utility cover extension assembly 17 as shown in FIG. 4.
The utility cover extension 10 has a bottom portion 26 and an upper portion 28. The bottom portion 26 has a bottom support surface 30 positionable adjacent the support flange 18 of the utility housing 12 and a bottom outer peripheral surface 32 extending upwardly from the bottom support surface 30. In the assembled condition, the outer peripheral surface 32 of the extension 10 is positioned adjacent to and is complimentary with the peripheral surface 20 of the housing 12. The support flange 18 includes a bottom surface 19 on which the bottom support surface 30 of the extension 10 rests.
The upper portion 28 of the extension 10 is provided for receiving the utility cover 16 therein. The upper portion 28 includes an upper support surface 34 which, when in the assembled condition, is adjacent to the bottom 22 of the cover 16 and supports the cover thereon. The upper portion 28 has an upper inner peripheral surface 36 extending upwardly from the support surface 34. The peripheral surface 36 is positionable adjacent to and complimentary with the outer peripheral surface 24 of the cover 16 when in the assembled condition. For ease of description, the inner peripheral surface 20 of the housing 12 and adjacent outer peripheral surface 32 of the bottom portion 26 of the cover extension 10 will be referred to as complimentary peripheral surfaces and the outer peripheral surface 24 of the cover 16 and adjacent inner peripheral surface 36 of the upper portion 28 of the cover extension 10 will be referred to as complimentary peripheral surfaces.
The extension 10 includes an extension frame 38 and a compressible material 40 forming the bottom and upper support surfaces 30, 34 respectively and the bottom and upper peripheral surfaces 32, 36 respectively. When in the unassembled condition, the circumference 42 of the bottom outer peripheral surface 32 of the extension 10 is greater than the circumference 44 of the peripheral surface 20 of the housing 12. Also, when in the unassembled condition, the circumference 46 of the upper peripheral surface 36 of the extension 10 is greater than the circumference 48 of the outer peripheral surface 24 of the cover 16. Accordingly, an interference fit between the complimentary peripheral surfaces 20, 32 and the complimentary peripheral surfaces 24, 36 exists in the unassembled condition.
When in the assembled condition, the compressible material 40 is compressed so that the circumference of the peripheral surfaces 32, 36 of the extension 10 conform to and are substantially equal to the circumferences 44, 48 of the peripheral surfaces 20, 24 respectively. The compressible material 40 in the assembled condition provides for frictional engagement between the complimentary parts 10 and 12 and the complimentary parts 10 and 16 of the utility cover extension assembly 17 The support surfaces 30, 34 are also compressed in an assembled condition.
The outer peripheral surface 24 of the cover defines an obtuse angle of from between 91 degrees to 110 degrees with the plane of the bottom surface 22 of the cover 16. Likewise, the outwardly sloping peripheral surface 20 of the housing 12 forms an obtuse angle of from between 91 degrees and 110 degrees with the plane of the bottom surface 19 from which the peripheral surface 20 extends. By providing the obtuse angles between the peripheral surface 12 and bottom 22 of the cover 16 and the peripheral surface 20 and bottom surface 19 of the housing 12, the extension 10 may be more readily assembled with the housing and cover 12, 16 respectively. This angular relationship provides for advantageous assembly of the extension 10, housing 12, and cover 16 by providing a camming action to compress the material 40 as the components 10, 12 and 16 are assembled as will be hereinafter described. It should be understood that the term circumference as used in connection with angular peripheral surfaces is the circumference at any particular point along the angular surface.
The compressible material 40 extends continuously about the entire circumferences 42, 46 of the peripheral surfaces 32, 36 of the extension 10 and continuously about the bottom and upper support surfaces 30, 34 of the extension 10. When the compressible material is compressed, a seal is created between the complimentary parts 10, 12, and the complimentary parts 10, 16 of the utility cover extension assembly 17 to resist the flow of surface water and other contaminants through the complimentary surfaces 24, 36, and 22, 34 and 20, 32 and 19, 30.
In the embodiment of the utility cover extension 10 shown in FIGS. 1-4, the utility cover extension 10 includes an extension frame 38 and a compressible material 40 secured to the frame. The compressible material may be selected from a wide variety of both natural and synthetic materials having the properties of compressibility, flexibility, density, elongation, toughness, and impermeability necessary to meet the service conditions described above. The desired characteristics of such a compressible material when used as described by the present invention increases and maintains the frictional forces maintaining the components of the utility cover extension assembly 17 in an assembled relationship, absorbs impact loadings, resists the flow of surface liquids and contaminants through the complimentary surfaces of the utility cover extension assembly 17, decreases the noise level of the extension assembly under operating service conditions, is able to operate under various temperature conditions and in various chemical environments and extends the effective service life of the utility cover extension assembly 17. A wide variety of materials of both natural and synthetic origins and combinations thereof meet these requisites. For example, rubber and plastic materials may be used along with combinations of materials such as cork fillers bonded together with resinous, protein or synthetic binders.
In order to achieve the sealing properties of the present invention the material 40 has the characteristic of impermeability to water. This characteristic can be obtained by using a closed cell elastomer or flexible plastic of the appropriate density and compressibility. Preferred materials for use as the compressible material 40 are cast microcellular urethane elastomers, polyurethane foams, rubber, and plastics if properly formulated and processed. Some examples are: polyisoprene, both natural and synthetic, styrene butadiene, polybutadiene, butyl rubber, chlorobutyl rubber, neoprene, ethylene propylene rubber, nitrile, polyacrylate rubber, polysulfide, silicone elastomers, flouroelastomers, polyethylene acrylate, polyvinyl acetate, epichlorohydrin, chlorosulfonated plyethylene, crosslinked polyethylene, polyethylene, polypropylene, plasticized polyvinyl chloride, polyvinilidene chloride, ionomer, thermoplastic polyester, and polyurethane gum rubber.
One preferred material is Uniroyal, Inc.'s "ADIPRENE" #L167, a polyurethane foam rubber further described by a formula recipe:
100 parts--L-167
0.3 parts--Water
0.3 parts--"DABCO-33LV"
1.4 parts--"DC-193"
16.0 parts--"BC"
These additives are furnished as follows:
DABCO-33LV: Air Products Inc., Allentown, Pa.
DC-193: Dow-Corning Inc., Midland, Mich.
BC: Palmer, Davis, Sieka Inc., Port Washington, N.Y.
The extension frame 38 of the present invention includes a base 56 having a top and a bottom surface 52, 54 respectively, with a lateral support portion 56 extending upwardly from the top surface 52 and terminating in a flange 62. The lateral support portion 56 has an inside surface 58 and the lateral support portion 56 and the outer portion of the base 50 has an outside surface 60.
In the embodiment described in FIGS. 1-4, the material 40 extends around the surfaces 52, 54, 58, 60 and the flange 62 and is bonded thereto. The frame 38 provides structural rigidity to the extension 10 and the strength to operate in the service conditions described above.
Means are provided to bond the compressible material 40 to the surfaces 52, 54, 58, 60 and flange 62. For example, a permanent adhesion of the cured "ADIPRENE" polyurethane foam rubber is accomplished by a chemical and mechanical bonding process by using the bonding agent 63 "CHEMLOK" #218 as manufactured by the Lord Corporation, Erie, Pa. The metal surfaces 52, 54, 58, 60, 62 of the extension frame 38 are thoroughly cleaned. The bonding agent 63 is then applied to the surfaces 52, 54, 58, 60, 62 of the extension frame 38 and allowed to dry The material 40 is then applied o the surfaces 52, 54, 58, 60, 62 in an elevated temperature environment. This chemical bonding procedure is further described in the product information catalog BS10-2026J of the Lord Corporation, Erie, Pa.
It is also within the contemplation of this invention to manufacture the compressible material 40 by molding, extruding or casting using the proper adhesive or bonding agent to attach or bond and secure the compressible material to the extension frame 38.
The present invention also provides methods to achieve the desirable features of the present invention. One such method includes cutting strips of the compressible material 40 out of a sheet with the proper dimensions and of sufficient length to go around the circumference of the bottom surface 54 and the outside surface 60 terminating underneath the flange 62. Alternatively, this strip of material may be cut sufficiently large to extend all the way around the extension frame 38 to form a continuous surface therearound which is necessary to achieve the desirable sealing characteristics. The strip of compressible material is then secured to the bottom surface and outside surface 54, 60 respectively by any conventional known means particularly suited to the compressible material selected, such as an adhesive molding in place by heat and pressure using a bonding agent and the like.
It should be understood that if it is necessary to only achieve the frictional and load absorbing characteristics of the present invention, strips of compressible material 40 may be placed along only portions of the outside surface 60 and bottom surface 54 to cushion the vertical impact energy loadings on the utility cover extension 10 and maintain the frictional relationship between the components of the assembly.
This method also includes cutting another strip of material 40 of the proper dimension to fit on the top surface 52 and inside surface 58 of the extension frame 38. This compressible material 40 is secured to the frame 38 in a manner similar to that described above in connection with the method of securing the compressible material to the bottom and outside surfaces 54, 60 respectively of the frame 38.
Another method of achieving the desirable features of the present invention is to form the compressible material 40 by molding the material into its desired shape. The molded material is then positioned about the extension frame 38 and bonded thereto by any means suited for the particular material of the frame 38 and the type of compressible material 40 used. One example is described above in connection with "ADIPRENE" used as the compressible material and "CHEMLOK" used as the bonding agent.
Yet another method to achieve the desirable features of the present invention is to position the extension frame 38 in the cavity of a mold, and mold the compressible material 40 about the extension frame after treating the frame with a bonding agent thereby accomplishing the bonding process simultaneously.
Various advantages and features of the molding process can be used to achieve various physical characteristics of material, such as a multiple layer material as described in connection with the embodiment disclosed in FIGS. 9-11.
While the above description includes bonding the compressible material 40 to the extension frame 38, it should be understood that it is within the contemplation of this invention to bond the compressible material to the surfaces 19, 20 of the housing 12 and surfaces 22, 24 of the cover 16 to obtain the desirable features of the present invention.
When it is desirable to repair or resurface a roadway, it becomes necessary for the original grade 64 of the roadway to be raised to a new grade or level 66. To raise the utility cover 16 so that the top 68 of the cover 16 is at the new grade 66, the cover 16 is removed from its seated position in the utility housing. The utility cover extension is positioned over the access opening 14 of the housing 12. The utility cover extension 10 is then moved down the outwardly sloping peripheral surface 20 and the compressible material 40 forming the bottom outer peripheral surface 32 is compressed as the extension moves in a downward direction. Since the peripheral surface 20 of the housing 12 is outwardly sloping, the peripheral surface 20 has a camming action to urge the compressible material 40 forming the peripheral surface 32 into a compressed condition.
As the extension 10 continues to move in a downward direction, the compressible material 40 forming the bottom support surface 30 contacts the bottom surface 19 of the flange 18 of the housing 12. Further downward movement of the extension 10 compresses the compressible material forming the bottom support surface 30 of the extension. In this position, the extension 10 is in the condition shown in FIG. 3 with the material 40 forming the bottom support surface 30 and bottom outer peripheral surface 32 being in a compressed condition.
After repairing or repaving the roadway to the new grade 66, the cover 16 is inserted into the extension 10. The outer peripheral surface 24 of the cover 16 is of a similar configuration to the peripheral surface 20 of the housing 12. The outer peripheral surface 24 of the cover 16 comes into contact with the inner peripheral surface 36 of the extension 10 and as the cover is moved in a downward position, the compressible material 40 forming the inner peripheral surface is compressed. The bottom surface 22 of the cover 16 comes into contact with the upper support surface 34 of the extension 10 as continued downward movement of the cover occurs. Further downward movement of the cover 16 compresses the compressible material 40 forming the upper support surface 34. In this assembled condition, the top 68 of the cover 16 is level with the new grade.
Accordingly, when assembled, the bottom outer peripheral surface 32 of the extension 10 defines an obtuse angle of from between 91 degrees and 110 degrees with the plane of the bottom support surface 30 and the upper inner peripheral surface 36 forms an obtuse angle of from between 91 degrees and 110 degrees with the plane of the upper support surface 34 from which the inner peripheral surface 36 extends. Even if the complimentary surfaces 19, 22 and 20, 24, respectively are worn, the compressible material provides sufficient flexibility to allow the same components to be used without requiring a new cover while still providing the advantageous features of the present invention.
The embodiments of the present invention shown in the drawings provide an extension frame 38 with the surfaces 58, 60 formed at an obtuse angle. This obtuse angle is the same as the obtuse angle of the peripheral surfaces 20, 24 of the housing 12 and cover 16, respectively. It should be understood that it is within the contemplation of this invention to form the surfaces 58, 60 at other angles, for example, at a 90 degree angle. In such a design, the extension frame may be more easily formed and the compressible material 40 is positioned between the extension frame 38 and the housing 12 and cover 16 to provide the advantageous features of the present invention.
The embodiments of the present invention shown in the drawings also describe the peripheral surfaces 32, 36 of the compressible material 40 of the extension 10 when in an unassembled condition formed at the obtuse angle of the peripheral surfaces 20, 24 of the housing 12 and cover 16, respectively. It should be understood that it is within the contemplation of this invention to form the peripheral surfaces 32, 36 at other angles when in an unassembled condition, for example, at a 90 degree angle. When such a utility cover extension is assembled with the housing 12 and cover 16, the compressible material 40 deforms to the obtuse angle of the peripheral surfaces 20, 24 of the housing 12 and cover 16, respectively, and provides the desirable features of the present invention.
In operation, the compressible material 40 absorbs the impact energy exerted under normal service conditions and dissipates that impact energy. It is believed that the compressible material 40 cold flows into the asperities on the surfaces 22, 24 of the cover 16 and surfaces 19, 20 of the housing 12 to create a bonding therebetween. Thus, when an impact loading occurs, the compressible material flexes and absorbs the energy without creating any wear between the metal components. By so securing the components of the extension assembly 17 in an assembled condition, relative movement between the components is resisted.
The compressible material 40 when so compressed operates as a seal between the extension 10 and housing 12 and also a seal between the extension 10 and the cover 16 to thereby resist the flow of surface water and other contaminants into the access opening 14 of the utility housing.
The compressible material 40, when in an assembled condition reduces the noise generated under normal service conditions, for example, reducing the noise generated by vehicles passing over and impacting the cover 16.
Utility cover assembly 10 of the present invention may have a wide variety of constructions, designs and geometric configurations. The terms "circumference" and "peripheral surface", both singular and plural, as used in this application, apply to not only circular configurations but also to a wide variety of geometric configurations. For example, the circumferences and peripheral surfaces of the utility cover extension 10 may be round, square, rectangular, or triangular or any other geometric configuration depending on the shape of the utility housing 12 and cover 16. For example, manhole cover extensions may be of generally round, square or rectangular shapes and valve covers and meters may be round, square, rectangular or triangular and in other cases take on other geometric configurations. It should be understood that the present invention may be embodied in any such geometric configurations.
The specific utility cover extension construction shown in FIGS. 1-4 should be considered as primarily illustrative. Other constructions are illustrated in FIGS. 5-14. For ease of description, these other constructions are numbered with numerals the same as those used in FIGS. 1-4 to denote common parts, where appropriate, followed by a suffix letter to denote each specific embodiment. For example, the common parts of the construction shown in FIGS. 5-8 will be followed by the suffix "a", the common parts of the construction shown in FIGS. 9-11 by the suffix "b", and the common parts of the construction shown in FIGS. 12-14 by the suffix "c".
The utility cover extension 10a shown in FIG. 5 has an extension frame 38a with a compressible material 40a. The extension frame 38a is similar in construction with the extension frame 38 except that the extension frame 38a is formed of a plurality of peripheral segments 70, 72, 74, and 76 joined by a suitable attaching means such as the bolts 78. Such a design is further shown in applicant's U.S. Pat. No. 3,773,428.
The ends 79 of the peripheral segments, 70, 72, 74, and 76 have threaded openings 80, 82 in the opposing ends thereof. The threaded opening 80 is threaded in one direction with the threaded opening 82 being threaded in the opposite direction. The bolts 78 have complimentary threads therein so that when the bolts are rotated in one direction, the circumferences of the surfaces 58a, 60a increase and when the bolts 78 are rotated in the other direction, the circumferences of the surfaces 58a, 60a are decreased. The compressible material 40a mounted on the extension frame 38a is cross-sectionally similar to that described in connection with the embodiment described in FIGS. 1-4 except for the spaces 84 between the ends 79 of the segments 70, 72, 74 and 76.
FIG. 5 is an exploded sectional perspective view of the extension 10a and housing 12a and shows the utility cover extension 10a with portions of the compressible material 40a in the area of the openings or spaces 84 between the ends 79 of the segments 70, 72, 74, and 76.
To provide the advantageous sealing feature provided by the present invention, the compressible material 40a in the areas between the spaces 84 must be reinforced so that a seal is effected between the components 10a, 12a, and 16a of the utility cover extension assembly 17a shown in FIG. 8. As shown in FIG. 6, in an unassembled condition, the compressible material 40a does not have a portion of the extension 38a extending therethrough in the area of the space 84. It should be understood that extension frames of other constructions and designs may be utilized which allow for telescopic portions of the extension frame 38a to allow for improved rigidity of the extension 10a when moved between a contracted and assembled position.
The compressible material 40a in the area between the space 84 extends between the surfaces 30a, 32a, 34a, and 36a of the extension 10a with a cut out 86 between the surfaces 30a, 34a which allows space for the bolt 78 for insertion of a wrench or the like to rotate the bolt. This additional material creates rigidity and strength to provide the sealing characteristics between the extension 10a, housing 12a, and utility cover 16a described above in connection with the utility cover extension assembly 17.
Preferably, the compressible material 40a is molded to provide he reinforced sections 85. The compressible material 40a is molded in a separate mold and assembled with the extension frame 38 with a bonding agent between the extension frame and the compressible material 40a. The molding process may also be accomplished by directly molding the material 40a to the extension frame 38a. Other known methods, such as extrusions, may be used with rubber inserts to provide the reinforced sections 85.
In the unassembled condition shown in FIG. 6, the circumference 46a of the extension 10a is greater than the circumference 44a of the housing 12a and the circumference 42a of the extension is less than the circumference 48a of the utility cover 16a. It should be understood for purposes of describing the extension 10a in the assembled and unassembled condition, the circumference of the surfaces 58a, 60a of the extension frame 38a shown in FIG. 5, are the same in both the unassembled condition and assembled condition, but in order to move between the assembled and unassembled condition, the bolts 78 are advantageously rotated to allow for more ready assembly of the components of the utility cover extension assembly 17a.
To assemble the utility cover extension 10a to the utility housing 12a, the bolts 78 are rotated to decrease the circumferences of the surfaces 58a, 60a of the extension frame 38a. As the circumference of the extension frame 38a is so decreased, the spaces 84 between the ends 79 of the segments 70, 72, 74, and 76 decrease and the reinforced sections 85 of the compressible material 40a are accordingly compressed. In addition, the circumferences of the outside surface 60a of the frame 38a and correspondingly the circumference of the peripheral surface 32a, 36a is decreased.
When the utility cover 10a is positioned in this contracted position, the utility cover extension 10a may be more readily positioned in the utility housing 12a. When the extension 10a is positioned in the housing 12a the compressible material 40a forming the bottom support surface 30a is compressed. After compression of the material 40a forming the bottom support surface 30a and outer peripheral surface 32a when positioned in the housing 12a, the bolts 78 are rotated in a direction which provides for the expansion of the extension frame 38a to an assembled position. As the extension frame 38a is moved to its assembled position, the bottom outer peripheral surface 32a is compressed. When in the assembled condition, the cover 16a is assembled with the extension 10a in a manner as described above in connection with the embodiment shown in FIGS. 1-4 and the components 10a, 12a, and 16a are in an assembled relationship as shown in FIG. 8.
Over the short span of the reinforced sections 85, an effective seal between the complimentary surfaces 22a, 34a and 24a, 36a of the cover 16a and extension 10a respectively is created. Likewise, a seal is provided between the complimentary surfaces 19a, 30a and complimentary peripheral surfaces 20a, 32a of the housing 12a and extension 10a respectively.
The utility cover extension 10b shown in FIGS. 9-11 has an extension frame 38b with a compressible material 40b. The compressible material 40b has an inner layer 90 and an outer layer 92 that are bonded together. The inner layer 90 is bonded to the extension frame 38b as described above in connection with the extension frame 38 and compressible material 40. The outer layer 92 is formed from a flexible wear resistent material and describes the peripheral surfaces 32b, 36b and support surfaces 30b, 34b of the extension 10b. The outer layer 92 is selected for its wear resistent qualities and is bonded to the inner layer 90.
The outer layer 92 has cold flow characteristics wherein the material flows into the asperities on the surfaces 22b, 24b of the cover 16b and the surfaces 19b, 20b of the housing 12b to create an mechanical bond therewith.
When in the unassembled condition, the circumference 42b of the bottom outer peripheral surface 32b of the extension 10b is greater than the circumference 44b of the peripheral surface 20b of the housing 12b. Also, when in the unassembled condition, the circumference 46b of the upper peripheral surface 36b of the extension 10b is greater than the circumference 48b of the outer peripheral surface 24b of the cover 16b. Accordingly, an interference fit between the complimentary peripheral surfaces 20b, 32b and the complimentary peripheral surfaces 24b, 36b exists in the unassembled condition.
When in the assembled condition, the compressible material 40b is compressed so that the circumference of the peripheral surfaces 32b, 36b of the extension 10b conform to and are substantially equal to the circumferences 44b, 48b of the peripheral surfaces 20b, 24b respectively. The compressible material 40b in the assembled condition provides for frictional engagement between the complimentary parts 10b and 12b and the complimentary parts 10b and 16b of the utility cover extension assembly 17b.
The compressible material 40b extends continuously about the entire circumferences 42b, 46b of the peripheral surfaces 32b, 36b of the extension 10b and continuously about the bottom and upper support surfaces 30b, 34b of the extension 10b. When the compressible material is compressed, a seal is created between the complimentary parts 10b, 12b, and the complimentary parts 10b, 16b of the cover extension assembly 17b to resist the flow of surface water and other contaminants through the complimentary surfaces 24b, 36b, and 22b, 34b and 20b, 32b and 19b, 30b.
When it is desirable to repair or resurface a roadway, it becomes necessary for the original grade 64b of the roadway to be raised to a new grade or level 66b. To raise the utility cover 16b so that the top 68b of the cover 16b is at the new grade 66b, the cover 16b is removed from its seated position in the utility housing. The utility cover extension 10b is positioned over the access opening 14b of the housing 12b. The utility cover extension 10b is then moved down the outwardly sloping peripheral surface 20b and the compressible material 40b forming the bottom outer peripheral surface 32b is compressed as the extension moves in a downward direction. Since the peripheral surface 20b of the housing 12b is outwardly sloping, the peripheral surface 20b has a camming action to urge the compressible material 40b forming the peripheral surface 32b into a compressed condition. During this assembly, the outer layer 92 resists damage by any abrasion caused by this assembly process.
As the extension 10b continues to move in a downward direction, the compressible material 40b forming the bottom support surface 30b contacts the bottom surface 19b of the flange 18b of the housing 12b. Further downward movement of the extension 10b compresses the compressible material forming the bottom support surface 30b of the extension. In this position, the extension 10b is in the condition shown in FIG. 3 with the material 40b forming the bottom support surface 30b and bottom outer peripheral surface 32b being in a compressed condition.
After repairing or repaving the roadway to the new grade 66b, the cover 16b is inserted into the extension 10b. The outer peripheral surface 24b of the cover 16b is of a similar configuration to the peripheral surface 20b of the housing 12b. The outer peripheral surface 24b of the cover 16b comes into contact with the inner peripheral surface 36b of the extension 10b and as the cover is moved in a downward position, the compressible material 40b forming the inner peripheral surface is compressed. The bottom surface 22b of the cover 16b comes into contact with the upper support surface 34b of the extension 10b as continued downward movement of the cover occurs. Further downward movement of the cover 16b compresses the compressible material 40b forming the upper support surface 34b. During assembly, the outer layer 92 slides across the cover 16 and resists abrasion thereof. In this assembled condition, the top 68b of the cover 16b is level with the new grade.
In operation, the compressible material 40b absorbs the impact energy exerted under normal service conditions and dissipates that impact energy. It is believed that the compressible material 40b of the outer layer 92 cold flows into the asperities on the surfaces 22b, 24b of the cover 16b and surfaces 19b, 20b of the housing 12b to create a bonding therebetween Thus, when an impact loading occurs, the compressible material flexes and absorbs the energy without creating any wear between the metal components. By so securing the components of the extension assembly 17b in an assembled condition, relative movement between the components is resisted.
The wear resistent properties of the outer layer 92 provide for maintaining seal between the complimentary surfaces 30b, 19b and 32b, 20b of the extension 10b and housing 12b, respectively, and the complimentary surfaces 34b, 22b and 36b, 22b of the extension 10b and cover 16b, respectively.
The utility cover extension 10c shown in FIGS. 12-14 has an extension frame 38c with a compressible material 40c. The extension frame 38c is similar to the construction of the extension frame 38a which provides for adjustment of the circumference of the extension 38c by means of the bolts 78c. The compressible material 40c is formed in the shape of rings 94, 96, 98.
Means are provided to secure the rings 94, 96, 98 to the surfaces 52c, 54c, 60c of the extension frame 38a. The rings 94, 96, 98 are fitted into the slots 100, 102 and 104 and extend about the circumferences thereof to form a part of the surfaces 30c, 32c, 34c of the extension 10c.
When in the unassembled condition, the circumference 42c of the bottom outer peripheral surface 32c of the extension 10c formed by the ring 96 is greater than the circumference 44c of the peripheral surface 20c of the housing 12c. Accordingly, there is an interference fit between the complimentary peripheral surfaces 20c, 32c.
When in the assembled condition, the compressible material 40c is compressed so that the circumference of the peripheral surface 32c of the extension 10c conform to and are substantially equal to the circumferences 44c of the peripheral surfaces 20c. The compressible material 40c in the assembled condition provides for frictional engagement between the complimentary parts 10c and 12c and the complimentary parts 10c and 16c of the utility cover extension assembly 17c. The support surfaces 30c, 34c are also compressed in an assembled condition.
The compressible material 40c extends continuously about the entire circumferences 42c of the peripheral surface 32c, of and continuously about the bottom and upper support surfaces 30c, 34c of the extension 10c. When the compressible material is compressed, a seal is created between the complimentary parts 10c, 12c, and the complimentary parts 10c, 16c of the utility cover extension assembly 17c to resist the flow of surface water and other contaminants through the complimentary surfaces 22c, 34c and 20c, 32c and 19c, 30c.
In operation, the compressible material 40c absorbs the impact energy exerted under normal service conditions and dissipates that impact energy and also provides a seal about the complimentary peripheral surfaces. Accordingly, the engagement between the utility housing 12c and extension 10c is maintained under normal service conditions.
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A utility cover extension and its process of installation are shown. The extension is adapted to rest on the cover support flange of and make a snug fit in a utility housing for a manhole cover. The extension provides an access opening above the housing. It has a rim and seat that furnish lateral retention and a new, substantially higher elevation for the cover. The extension has at least one spreadable joint for expanding its periphery against the constraint of the housing, and there is a gap in the seat at the joint when the extension is expanded. A discrete closure comprising compressible polymer is applied at the gap for preventing the substantial infiltration of surface water therethrough.
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FIELD OF INVENTION
[0001] The present invention relates to a process for the preparation of Cefditoren of formula (I), the pivaloyloxy methyl ester (Cefditoren pivoxil) of which is well known to be used as an antibiotic agent.
[0002] The present invention more particularly relates to a process for the preparation of Cefditoren using the thioester derivatives of formula (II)
[0003] wherein, R 1 represents C 1 -C 4 alkyl or phenyl. The thioester derivatives of formula (II) have been disclosed and claimed in the U.S. Pat. No. 6,388,070.
BACKGROUND OF THE INVENTION
[0004] Acid chlorides, anhydrides, esters, amide etc. are reported in the chemical literature for activation of carboxylic acid of formula (III).
[0005] wherein, R 2 represents H, trityl, CH 3 , CR a R b COOR c , (in which R a and R b independently of one another represent hydrogen or methyl and R c represents H or C 1 -C 7 alkyl).
[0006] In these, activation in the form of acid chloride required protection and deprotection of NH 2 group.
[0007] Activation of acid (III) is reported by SO 2 Cl 2 /DMF in U.S. Pat. No. 5,856,502 and SOCl 2 /DMF in U.S. Pat. No. 5,037,988. These processes suffer the limitation of using harmful and pungent smelling chemicals like SOCl 2 , SO 2 Cl 2 along with solvents like benzene, toluene, etc. and stringent conditions required for carrying out the reactions at commercial scale.
[0008] In U.S. Pat. Nos. 4,576,749 and 4,548,748 the acid of formula (III) has also been activated by reacting with 1-hydroxybenzotriazole (HOBT) or 2-mercaptobenzothiazole (MBT) in the presence of dicyclohexylcarbodiimide (DCC) to produce reactive ester of the acid (III) which then reacted to cephem moiety to prepare cephem antibiotics, but the processes are time consuming and with low yields, hence not suitable.
[0009] U.S. Pat. No. 4,7678,52 discloses a process for the production of cephems by acylating 7-amino-3-cephem-4-carboxylic acid with 2-mercaptobenzothiazolyl-(Z)-2-(2-aminothiazol4-yl)-2-methoxyiminoacetate (MAEM). Similarly, U.S. Pat. No. 5,026,843 (1991) discloses a process for preparing ceftriaxone disodium hemiheptahydrate by acylation of ACT by using MAEM as acylating agents in good yield and quality. Thus, MAEM has become the standard acylating agent for the preparation of cephalosporins having an oximino group and a 2-aminothiazolyl group in 7-position of cephem compounds.
[0010] However, the synthesis of MAEM from acid (III) and 2,2′-dithio-bis-benzothiazole involves use of costly condensing agent triphenylphosphine (TPP). Moreover, during condensation of MAEM with 7-amino-3-cephem-4-carboxylic acid compound (IV), a toxic compound MBT is also produced as a byproduct, see e.g., Chemical Abstracts, 111, 19243 p (1989) which is difficult to remove completely.
[0011] Thus, it is evident that the procedures described in the prior art for preparation of these antibiotics are complex, involving protection, deprotection and are associated with toxic byproduct generation. Hence, there is a need to develop new acylating agents which are capable of transferring the 2-aminothiazolyl moiety to cephem compounds of formula (IV) in good yield but without producing this toxic byproduct. On the similar lines, a new thioester was reported by D. G. Walker, Tet. Lett. 1990, 31,6481 to acylate the cephem moiety to get cefepime sulfate but yields obtained by using this thioester were in the range of 54-73% which cannot be considered as good yield to operate the process at commercial scale. The use of this thioester was also reported in the Tet. Lett. 1990, 31, 6481 only for cefepime and not for other cephalosporins. This thioester was exploited in U.S. Pat. No. 5,869,649 for making three other important cephalosporin antibiotics.
OBJECTIVES OF THE INVENTION
[0012] The primary objective of the invention is to provide a process for the preparation of Cefditoren of formula (I), using the thioester derivatives of thiazolyl acetic acid of the general formula (II), which is a better reactive derivative than the other reactive derivatives.
[0013] Another objective of the present invention is to provide a process for the preparation of Cefditoren of formula (I), which is simple, high yielding and cost effective.
[0014] Still another objective of the present invention is to produce Cefditoren of formula (I), which is highly pure and free from toxic by-products.
SUMMARY OF THE INVENTION
[0015] Accordingly, the present invention provides a process for the preparation of Cefditoren of formula (I), which comprises acylating 7-amino-cephem carboxylic acid of the general formula (IV) where R 3 is hydrogen or trimethylsilyl group with thioester derivative of formula (II) where R 1 represents C 1 -C 4 alkyl or phenyl in an organic solvent and in the presence of an organic base at a temperature in the range of −10° C. to 30° C.
[0016] The process is shown in Scheme-1 herebelow:
[0017] Wherein, R 1 and R 3 are as defined above.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The condensation of cephem compound of formula (IV) with thioester of formula (II) is performed by two different methodologies (a) by acylatine the compound of formula (IV) (when R 3 is H) with formula (II) in an aqueous organic solvent; (b) by acylating the compound of formula (IV (when R 3 is silyl) with formula (II) in an aprotic organic solvent. Both the approaches are comparable and afforded excellent yields and purities of cephalosporin antibiotics of formula (I).
[0019] Acylation of compounds of formula (IV) (when R 3 is H) is performed in the presence of a water miscible solvent selected from tetrahydrofuran (THF), acetonitrile, acetone, dioxane, N,N-dimethylformamide etc., but the preferable solvent is THF or acetonitrile.
[0020] Acylation of compound of formula (IV) (when R 3 is silyl) was carried out in an aprotic organic solvent selected from halogenated hydrocarbons, toluene, alkyl ethers etc., but preferable solvent is dichloromethane. Suitable silylating agent used for the reaction is selected from hexamethyldisalazane, bis(trimethyl)silylacetamide or trimethylsilyl chloride.
[0021] In another embodiment of the present invention, the organic base may be selected from triethylamine, diethylamine, tributylamaine, N-alkylpyridine, N-alkylanilines, 1,8-diazabicyclo[5.4.2]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, N-methylmorpholine, 1,4-diazabicyclo[2.2.2]octane, 4-dimethylamino pyridine or mixtures thereof.
[0022] In another embodiment of the present invention, the Cefditoren of formula (I) obtained is a syn-isomer.
[0023] In yet another embodiment of the present invention, the Cefditoren of the formula is Z-isomer.
[0024] The present invention provides a method by which cephalosporin antibiotics are obtained in high purity (95-99%) and excellent yield (79-95%) without the necessity for protecting the amino group of the acylating agents and the production of toxic byproduct namely 2-mercaptobenzothiazole is avoided.
[0025] Many other beneficial results can be obtained by applying disclosed invention in a different manner or by modifying the invention with the scope of disclosure. However, since the major characteristic feature of the present invention resides in the use of novel reactive thioester derivatives of thiazolyl acetic acid of the general formula (II) in preparing the Cefditoren of formula (I) the technical scope of the present invention should not be limited to the following examples.
[0026] The following examples are provided to illustrate but not to limit the claimed invention.
EXAMPLES
Example-I
[0027] Synthesis of 2-mercapto-5-phenyl-1,3,4-oxadiazolyl-(Z)-2-(2-aminothiazol-4-yl)-2-methoxyimino acetate (II):
[0028] (Z)-(2-aminothiazol-4yl)methoxyimino acetic acid (20.1 g), triethylamine (22.2 g) were suspended in dry dichloromethane (150 ml), and then bis-(2-oxo-oxazolidinyl) phosphinic chloride (25.4 g) was added in one lot at 0-5° C. and stirred for 1 hr. The 2-mercapto-5-phenyl-1,3,4-oxadiazole (21.3 g) was added at 0-5° C. The reaction mixture was stirred for 3-4 hours. After the reaction was complete, distilled water (100 ml) was added to the reaction solution and the mixture was stirred for 10 min. The organic layer was separated and washed successively with 2% aq. solution bicarbonate solution (100×2 ml) and saturated saline (100 ml), dried over sodium sulphate, filtered and then concentrated under reduced pressure. To the residue, IPE (300 ml) was added and solid was filtered, washed with IPE (100 ml). Dried to obtain 30.6 g (yield 85 %) of the title compound as light yellow solid.
[0029] Melting point: 109-110° C. 1 HNMR (DMSO-d 6 ): δ3.90(3H,s,N—OCH 3 ), 7.11(1H,s, thiazole ring proton), 7.29(2H,bs,NH 2 ), 7.6-7.9(5H, m, —C 6 H 5 ) 13 C-NMR (Acctone-d 6 ): δ 63.16, 108.7, 122.1, 129.7, 132.6, 133.7, 141.6, 146.75, 159.3, 159.6, 169.7, 173.1.
Example-II
[0030] 3-[(Z)-2-(4-methyl-5-thiazolyl)vinyl]-7-[(Z)-(2-aminothiazolyl-4-yl)-2-(methoxyimino)acetamido]-3-cephem-4-carboxylic acid (Cefditoren acid):
[0031] A mixture of THF (250 ml) and water (150 ml) was stirred under inert atmosphere. At 0° C.-1° C., 7-amino-3-[(Z)-2-(4-methyl-5-thiazolyl)vinyl]-3-cephem-4-carboxylic acid (25.0 g) and 2-mercapto-5-phenyl-1,3,4-oxadiazolyl-(Z)-2-(2-aminothiazol-4-yl)-2-methoxyimino acetate (33.3 g) obtained in Example I were added. Triethylamine (10.5 g) was slowly added to reaction by maintaining the pH between 7.5 to 8.5. The reaction was monitored by HPLC. After 4-5 hrs., the reaction mixture was extracted by methylene chloride. The aqueous layer is subjected for charcoal (0.125 g) treatment. Ethylacetate was added to the filtrate and the solution was acidified with dil. HCl at 10° C. to pH 3.0. The solid separated was filtered, washed with water and ethylacetate and then dried under vacuum at 40-45° C. to get Cefditoren acid, 35.0 g (yield 90 %).
[0032] HPLC (purity)=96-98%
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The present invention provides a process for the preparation of Cefditoren of formula (I)
which comprises acylating 7-amino-cephem carboxylic acids of the general formula (IV), where R 3 is hydrogen or trimethylsilyl with thioester derivatives of the formula (II), where R 1 represents C 1 -C 4 alkyl or phenyl in an organic solvent in the presence of an organic base at a temperature in the range of −10 ° C. to 30 ° C.
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RELATED APPLICATION
This application claims priority to provisional patent application Ser. No. 60/062,108 filed Oct. 14, 1997.
TECHNICAL FIELD
The present invention relates to a method for constructing an implant by placement of a paste comprising a stimuli sensitive polymer solution carrying a biocompatible ceramic component which hardens under physiological conditions to form a solid implant. The implant may also include a therapeutic agent or a radioisotope.
BACKGROUND OF THE INVENTION
Many researchers have experimented with drug delivery vehicles based on the use of controlled release implant materials. Others have sought to provide improved implants for filling in tissue losses from age or trauma, to hard or soft tissues. Calcium phosphate pastes have been suggested as bone and dental fillers. Gels have been used as control release devices and as fillers. Representative studies are discussed below.
In U.S. Pat. No. 4,188,373, certain polyols are used in aqueous compositions to provide thermally gelling aqueous systems. In these systems, the sol-gel transition temperature can be changed by manipulating the concentration of polymer. In U.S. Pat. Nos. 4,474,751; '752; '753; and 4,478,822 drug delivery systems are described which utilize thermosetting gels. In these systems, both the gel transition temperature and/or the rigidity of the gel can be modified by adjustment of the pH and/or the ionic strength, as well as by the concentration of the polymer. U.S. Pat. Nos. 4,883,660; 4,767,619; 4,511,563; 4,861,760, and 4,911,926 also disclose gels that deliver pharmaceutical compositions.
In U.S. Pat. No. 4,895,724, compositions are disclosed for the controlled release of pharmacological macromolecular compounds contained in a matrix of chitosan. Chitosan can be cross-linked utilizing aldehydes, epichlorohydrin, benzoquinone, etc. In U.S. Pat. No. 4,795,642, discloses gelatin-encapsulated, controlled-release pharmaceutical compositions, wherein the gelatin encloses a solid matrix formed by the cation-assisted gelation of a liquid filling composition incorporating a vegetable gum together with a pharmaceutically-active compound. The vegetable gums are disclosed as polysaccharide gums such as alginates which can be gelled utilizing a cationic gelling agent such as an alkaline earth metal cation.
Osmotic drug delivery systems are disclosed in U.S. Pat. No. 4,439,196 which utilize a multi-chamber compartment for holding osmotic agents, adjuvants, enzymes, drugs, pro-drugs, pesticides, and the like. These materials are enclosed by semipermeable membranes so as to allow the fluids within the chambers to diffuse into the environment into which the osmotic drug delivery system is in contact. U.S. Pat. No. 5,587,175 teaches a process for forming a protective corneal shield or an ablatable corneal shield or mask in situ comprising administering to the eye of a mammal an aqueous composition capable of being gelled in situ to produce an hyper osmotic, hypo osmotic, or iso osmotic aqueous gel having a controlled pH, said aqueous composition, including at least one film forming polymer; and gelling said film forming polymer in situ to form said protective corneal shield or ablatable corneal shield or mask.
U.S. Pat. No. 3,949,073 discloses injectable atelocollagen solutions which precipitate at body temperature, thus leading to the formation of fibers which remain at the injection site whereas the excipient is progressively resorbed. U.S. Pat. No. 5,658,593 in one embodiment provides micro capsules based on atelocollagen optionally mixed with a glycosaminoglycan such as chondroitin-4-sulfate, the micro capsules containing granules of hydroxyapatite in suspension in a viscous bio compatible carrier solution of a gel of atelocollagen optionally mixed with a glycosaminoglycan, in particular chondroitin-4-sulfate, for use as a filler material in forming injectable implants.
U.S. Pat. No. 5,626,861 teaches a method for the fabrication of three-dimensional macro porous polymer matrices for use as bone graft or implant material was developed. The composites are formed from a mixture of biodegradable, bio compatible polymer and hydroxyapatite (HA), a particulate calcium phosphate ceramic. The method leaves irregular pores in the composite between 100 and 250 microns in size by formation of a solid gel comprising a soluble material and dissolving the material to form voids in the gel. In a preferred embodiment, implants are composed of a 50:50 poly(lactide-co-glycolide) (PLGA) polymer and reinforced by hydroxyapatite. Mechanical and histological analysis showed the matrix fabricated by this method to be structurally and mechanically similar to cancellous bone. Prior to degradation, pure polymer specimens exhibited an elastic modulus of 293 MPa and specimens which were 50% HA by weight exhibited a modulus of 1459 MPa. After six weeks of degradation under physiological conditions, the reinforcing effect of ceramic loading had diminished. Modulus of polymer matrices at all HA load levels had decreased sharply to approximately 10 MPa. Mean macro- and micro pore diameters of the polymer specimens were 100 mu m and 20 mu m respectively and remained constant throughout degradation. The implants are hardened, leached and then implanted into the subject where they are slowly degraded by natural bodily action over a period of time. The implant size and shape must be predetermined and thus may not perfectly fit the site to be repaired.
B. R. Constantz, et als, 1995, Skeletal Repair by in Situ Formation of the Mineral Phase of Bone, Science, 267:1796-1799. Discloses a process for the surgical implantation of a paste that hardens in minutes under physiological conditions. The mixture comprises a mixture of calcium phosphates and sodium phosphate, and hardens due to the crystallization of dahlite, not mediated by a stimulus setting gel. The mixture hardens regardless of whether it is placed in the body. The paste is a hydroxyapatite precursor and does not include gel components.
B. Flautre, et als, 1996, Evaluation of Hydroxyapatite Powder Coated with Collagen as an Injectable Bone Substitute: Microscopic Study in Rabbit, J. Materials Science:Materials in Medicine, 7:63-67, discloses an injectable mix of hydroxyapatite and collagen but there is no disclosure of providing a stimulus response setting material. The group uses HA and atecollegen and chondrotin-4-sulfate formulated as micro spheres, similar to the patents discussed above. There is no provision for a gel which forms in response to a stimulus provided by exposure to the environment of the body, and there is no provision for differential loss of materials to provide a porous matrix. A further study by the same group, G. Pasquier, et als, 1996, Injectable Percutaneous Bone Biomaterials: an Experimental Study in a Rabbit Model, J. Materials Science:Materials in Medicine, 7:683-690, discloses mixtures comprising an orthopaedic acrylic cement (polymethylmethacrylate (“PMMA”)) and HA as well as HA and collagen. The PMMA was used as a reference bio-inert material. There is no disclosure of a stimulus setting gel for producing a composite which only hardens in response to a stimulus supplied by the body.
M. Ito, et als, 1994, Experimental Development of a Chitosan-bonded β-Tricalcium Phosphate Bone Filling Paste, Bio - Medical Materials and Eng., 4:439-499, discloses a composite of chitosan and tricalcium phosphate containing alkaline oxides of calcium, magnesium or zinc, which provided the conditions to produce setting. Again the material hardens without regard to stimulus supplied from the body. A similar study is reported by M. Takechi, et als, 1996, Non-decay Type Fast-setting Calcium Phosphate Cement Using Chitosan, J. Materials Science:Materials in Medicine, 7:317-322. Takechi uses sodium alginate or chitosan as a water insoluble gel to protect calcium phosphate cements from decay during setting under physiological conditions. In these materials the cements set as they normally do and the gel forms in response to the calcium provided by the cement. Again there is no gel formation in response to a physiological stimulus for the composite material.
There is a continuing and long felt need for alternative implant materials for the treatment of damage to bony tissues by injury or disease. The art has not heretofore provided a fluid or shapeable implant material which comprises both a bone growth supporting matrix such as a ceramic matrix, and a stimulus sensitive gel which can be shaped to fill an injury site and then hardens to support the injured tissue during healing. The art has not heretofore provided a polymer/ceramic composite suitable for use in bone repair wherein a stimuli sensitive gel is used as a fluid carrier to place a ceramic matrix into a damaged bony tissue wherein the gel hardens in response to a physiological condition such as temperature, pH, ionic strength and the like in the presence of the ceramic.
SUMMARY OF THE INVENTION
The present invention provides a composition which comprises a polymer or polymer solution that forms a gel under controlled parameters and a ceramic matrix, the composition being fluid under non-physiological conditions and non fluid under physiological conditions. Polymers may be resorbable or nonresorbable, natural or synthetic and the solution aqueous or non aqueous. Preferred polymers are poly-saccharides, random copolymers of (meth)acrylamide derivatives with hydrophillic comonomers, or polyamino acids, however any polymer or polymer solution that is biologically compatible and that is fluid under nonphysiological conditions and increases in viscosity under physiological conditions is suitable. As used in this application, physiological conditions means conditions normally found in a mammalian body such as pH in the range of 4 to 9, ionic strength of around 0.15 or temperature in the range of 35-40° C. Stimuli sensitive gel means a natural or synthetic polymer that increases in viscosity, gels or crosslinks in response to a stimulus such as a change in temperature, pH, ionic strength, light or the like. In contrast to the rigid composites synthetic grafts of the prior art, the compositions of the present invention may be injected at a trauma site, such as a fracture and shaped to fill any voids present, forming and in situ splint and scaffold for the growth of new bone. The composite may also serve as a controlled release device for a therapeutic agent such as a bone growth factor, an antibiotic, a chemotherapy drug, or a cytokine. The composites may include bone morphogenic proteins or other osteoconductive agents. Preferably the composites are formed in such a manner that the final solid implant is porous with macroscopic pores, preferably on the order of 100 to 200 microns in cross section. In an alternative embodiment a near net shape forming composition is employed wherein the polymer is a bio compatible, shear thinning polymer that forms a gel under ambient pressure and a ceramic component carried therein. The shear thinning polymer is one in which the polymer viscosity decreases in response to a stimulus such as ultrasonic vibration or injection.
Alternatively the invention may be viewed as a method of forming a solid implant in a mammalian body which comprises mixing a gel forming component with a ceramic forming component to provide a fluid mixture, placing the fluid mixture into a mammalian body wherein the fluid mixture gels after placement in the mammalian body in response to a stimulus provided by conditions present or induced in the mammalian body. Conditions present in the mammalian body includes normal body temperature, ionic strength, pH and the like. Conditions that can be induced in the body include ultrasonic vibration, externally applied magnetic fields, irradiation from a radiation source or light or other electromagnetic radiation. Preferably the fluid mixture comprises a gel forming polymer, a calcium phosphate ceramic, and a soluble material which will produce voids in the final implant, the voids having an average cross section in the range of 100 to 200 microns. The soluble material is preferably a second polymer which degrades or dissolves relatively rapidly under physiological conditions. Especially preferred polymers dissolve by enzymatic action leaving non toxic, non irritating residues.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plot of the viscosity of 30 wt % hydroxyapatite (HAP) slurries with different polymers.
FIG. 2 is a plot of solids loading effect on the viscosity of HAP in 0.4 wt % carrageenan.
FIG. 3 is a plot of solids loading for three polysaccharide polymers.
FIG. 4 is a plot of temperature against viscosity carrageenan and HAP carrageenan supensions.
FIGS. 5 a and 5 b are Scanning Electron Micrographs showing the structures of 30 wt % HAP in 2 wt % carrageenan (a) and 40 wt % HAP in 2 wt % carrageenan (b).
FIG. 6 is a plot of the dissolution of HAP/carrageenan composite and HAP powder at pH 6.5 in a solution containing 0.125 mM Ca Cl 2 , 0.075 mM KH 2 PO 4 and 0.15 M NaCl.
FIG. 7 is a plot of the fraction of carrageenan leached from the composition in a simulated blood plasma solution at 37° C. against time.
FIG. 8 is a plot of the viscosity of chitosan/HAP suspensions as a function of HAP wt % in 0.1N acetic acid.
FIG. 9 is a plot of the compression modulus of chitosan/HAP composites showing the effect of solids loading.
FIG. 10 is a plot of the compression modulus of HMW chitosan/HAP and chitosan/TCP showing the effect of the ceramic calcium phosphate phase.
FIG. 11 is a plot of the release of 5-fluorouricil from chitosan/HAP and chitosan/TCP compositions.
FIG. 12 is a plot comparing release of 5 fluorouricil and bovine serum albumin from a chitosan/HAP composition.
DETAILED DESCRIPTION OF THE INVENTION
Mechanisms by which bone may fail include brittle fracture from impact loading and fatigue from constant or cyclic stress. Stresses may act in tension, compression, or shear along one or more of the axes of the bone. A synthetic bone substitute must resist failure by any of these stresses at their physiological levels. A factor of safety on the strength of the implant may ensure that the implant will be structurally sound when subject to hyper physiological stresses. The solid implants of the prior art all require the injured bone to conform to the shape of the implant, requiring invasive surgery, long recovery times, fixation devices inserted into the bone, rigid external or internal splints and ingrowth of bone into the implant (“knitting”). Especially in the elderly, implants may fail due to failure of the bone regrowth and therefore failure of the implant to become joined to the bone. The rigid implant of U.S. Pat. No. 5,626,861 exemplifies the traditional approach of forming the implant ex vivo followed by surgical insertion into the injured bone.
In contrast to the prior art approach, it has now been found that stimuli sensitive gels can be combined with bone precursors such as hydroxyapatite ceramic particles to permit placement of fluid materials into damaged bone. The fluid mixtures form rigid structures on exposure to physiological conditions forming the implant as an integral part of the bony structure. The hardening of the implant may be triggered by any stimuli that can be provided directly or indirectly under physiological conditions. Examples of direct stimuli include temperature, pH, ionic strength, and the like, as they occur in a mammalian body. Examples of indirect stimuli that may be applied under physiological conditions include external heating or cooling, light and other electromagnetic radiation across the broad range of the spectrum, magnetic fields, induced or applied electrical charge or current, and the like.
A variety of bio compatible polymers can be used. The stimulus sensitive polymer may be any bio compatible polymer or copolymer which forms a gel or crosslinked structure in response to a stimulus which may include temperature, pH, ionic strength, solvent composition, sheer stress, light, and the like or a combination of these factors. Preferred polymers are described in co-pending application Ser. No. 08/870,368; Filed Jun. 6, 1997 incorporated herein by reference. Preferred stimulus sensitive polymers are random copolymers of a [meth-]acrylamide derivative and a hydrophilic comonomer, wherein the random copolymer is in the form of a plurality of linear chains having a plurality of molecular weights greater than or equal to a minimum gelling molecular weight cutoff.
The [meth-]acrylamide derivative is an N, N′-alkyl or pyrrolidone substituted [meth-]acrylamide including but not limited to N-isopropyl[meth-]acrylamide, N,N′-diethyl[meth-]acrylamide, N-[meth-]acryloylpyrrolidine, N-ethyl[meth-]acrylamide, and combinations thereof.
The hydrophilic co monomer is any hydrophilic co monomer that polymerizes with the [meth]acrylamide derivative to produce a bio compatible polymer. Preferred hydrophilic co monomers are hydrophilic [meth-]acryl- compounds such as carboxylic acids, [meth-]acrylamide derivatives, and the [meth-]acrylamide esters. The preferred aqueous solvent is deionized water, the solvent may also contain salts. Any biologically acceptable nonaqueous solvent that dissolves the polymer may also be used. In addition to the non-resorbable gelling copolymer of N-isopropyl(meth-)acrylamide and (meth)acrylic acid a biodegradable (resorbable) copolymer exhibiting similar gelation properties may also be used in polymer/ceramic composites that gel in response to physiological conditions. The biodegradable (resorbable) thermally gelling copolymer is obtained by grafting of the oligo(meth-)acrylamide derivative side chains on a biodegradable polymer backbone. Examples of the suitable biodegradable polymers include, polysaccharides and poly(aminoacids). The preferred biodegradable polymers are degraded by enzymatic hydrolysis to non toxic, non irritating residues.
Other polymers include the polysaccharides such as chitosan. Chitosans provide an additional new biodegradable component of polymer-ceramic composites suitable for injectable, resorbable templates for bone tissue regeneration. The rationale of using chitosans for this purpose is based on the fact that chitosan solutions gel in response to pH change from slightly acidic to physiological.
The unique aspect of this novel system is that at pH lower than 6.5 the chitosan-ceramic suspension is a paste-like flowable system and at physiological pH the polymer undergoes a phase transition resulting in entrapment of ceramic component within the reversible gel matrix. Thus, application of pH-reversible gels enables the creation of an implant which may be tailored to any shape of a bone defect needed to be filled. In contrast to the rapid setting gel/cement compositions which harden without regard to whether they are placed into the physiological environment, the present invention hardens on exposure to the physiological conditions that occur only after they are placed into the body. As a consequence, the stimulus response compositions of the invention and practice of the method of the present invention provides a bone filling biomaterial which can be pre-mixed and placed in stages following a sterilization or other treatment without premature setting.
Other polysaccharides such as xanthan gum, (available from Kelco), locust bean gum (available from Aldrich), and carrageenan (available from Aldrich, mainly K-carrageenan) are also useful in the invention. Carrageenan is less preferred because ot was found to cause irritation in an animal model.
Calcium phosphate ceramics are preferred for use as the ceramic component of implants in the repair of bone defects because these materials are non-toxic, non-immunogenic, and are composed of calcium and phosphate ions, the main constituents of bone. Both tricalcium phosphate (TCP) [Ca 3 (PO 4 ) 2 ] and hydroxyapatite (HA) [Ca 10 (PO 4 ) 6 (OH) 2 ] have been widely studied for this reason. Calcium phosphate implants may be osteoconductive, and have the apparent ability to become directly bonded to bone. As a result, a strong bone-implant interface can be created. However, the mechanical properties of calcium phosphate ceramics make them ill-suited to serve as a structural element. Ceramics are brittle and have low resistance to tensile loading. For this reason the ceramic component is combined with a polymeric component which adds elastic strength to the composition overcoming the shortcomings of the ceramic alone while retaining its positive features.
Other useful ceramics include other calcium or magnesium phosphates, aluminas, and the like. Any nontoxic, non immunogenic ceramic may be substituted for calcium phosphate in special circumstances such as an application wherein resporbtion of the ceramic component is not desired. Calcium phosphate ceramics have a degree of bioresorbability which is governed by their chemistry and material structure. High density HA and TCP implants exhibit little resorption, while porous ones are more easily broken down by dissolution in body fluids and resorbed by phagocytosis. However, TCP degrades more quickly than HA structures of the same porosity in vitro. In fact, HA is relatively insoluble in aqueous environments.
These solubility differences permit the use of mixed calcium phosphate ceramics to control the final structure of the implant by using for example TCP particles sized to be selectively dissolved by bodily fluids and provide voids in the final structure and HA particles sized to crystallize under physiological conditions to provide a mineral matrix to foster bone ingrowth into the implant. Preferably the voids will be in the range of 100 to 200 microns, the preferred size for supporting cell growth. Other non-toxic salts can be substituted for TCP for special purposes in forming voids in the implants. Implants having a macro porous structure which pores on the order of 100 to 200 microns are strongly preferred, although pores may be smaller as in 50 to 150 microns, larger as in 100 to 300 microns, or cover a broader range as in 50 to 500 microns and still provide useful implants.
Bone repaired with the use of a conventional polymeric implant such as those described in U.S. Pat. No. 5,626,861 will be required to be immobilized for between six and eight weeks, the standard procedure for conventional fractures. Where the implants of the present invention permit less invasive surgery and in situ fixation, the healing time may be reduced.
All fractures are subject to static loading even while immobilized in a cast, i.e., there is a load resulting from the weight of the bone itself. In order for the implant to unite bone segments in a fracture, it must have initial strength sufficient to provide the stability necessary for healing to begin. Further, the implant must retain a degree of strength throughout the bone remodeling cycle. Strength retention in the implant is governed by the degradation rate of the polymer in the polymer-ceramic composite. Both high strength retention over time and rapid weakening of the scaffold may be detrimental to the bone repair process. Slow implant resorption can shield immature skeletal tissue from the functional stresses necessary for complete remodeling. Conversely, rapid degradation may prematurely shift load beating to the new bone and cause its collapse. Preparation of example implants is described below to illustrate the invention and not by way of limitation. The examples are not intended to limit the invention which is defined by the claims set out below.
Procedures and Sample Preparation
Xanthan gum solution was prepared by addition of the powder at room temperature with stirring into deionized water or sodium chloride solution with desired ionic strength. The resulting smooth solution was then allowed to stand overnight to release all air bubbles. Solutions of locust beam gum and carrageenan gum were prepared at 70-75° C. and stirred until all powder is dissolved.
Hydroxyapatite(HAP)-xanthan gum and HAP-locust bean gum pastes were prepared by mixing the desired amount of HAP powder (Aldrich) into the polysaccharide solution using either a magnetic stir plate (<30 wt % HAP) or a mechanical stirrer at higher solids loading (>30wt % HAP). To prepare the HAP-carrageenan paste, the carrageenan solution was maintained at 70-75° C. in a water bath during mixing. Rheological measurements such as viscometry, strain sweep and oscillation were conducted using a Bohlin Rheometer.
HAP-polysaccharide paste samples prepared for mechanical testing and dissolution experiments were crosslinked in simulated blood plasma electrolyte solution overnight at room temperature. The simulated blood plasma electrolyte solution contains 3 mM KCl, 1.5 mM MgCl2, 4.2 mM NaHCO3, 1.0 mM KH2PO4, 138 mM NaCl and 2.5 mMCaCl2. It was adjusted to pH 7.4 by the addition of NaOH solution before use.
HAP-polysaccharide paste samples for microstructure and porosity studies were prepared and crosslinked in simulated blood plasma electrolyte solution as described above. They were then cut into small rectangles and quickly frozen in liquid nitrogen, then dried in vacuum at −12° C. for at least 24 hours.
HAP dissolution kinetics was measured using the constant composition method at 25° C. The in-vitro carrageenan leaching experiments were conducted in simulated blood plasma electrolyte solutions and concentration of leached carrageenan was determined by a colormetric method using methylene blue.
EXAMPLE 1
Rheological Studies of Calcium Phosphate-Binder Suspensions
The viscosity of HAP suspensions containing one of the three binders selected was measured as a function of binder properties, binder concentration, HAP solids loading and temperature.
Viscosity is a transport property. It must be sufficiently low to facilitate injectability. A shear thinning behavior is desired. This means that at very low shear rates suspended HAP particles remain stationary because the high viscosity of the binder solution was below the yield point. Higher shear rates that are encountered during pouring or during vibration can effectively reduce the viscosity. As shown in FIG. 1, all three slurries containing 30 wt % HAP showed shear thinning behavior. Among them, HAP suspension containing carrageenan had the lowest viscosity even though the carrageenan concentration was higher (0.4 wt %) than the other two binders (0.25 wt %).
Solids loading had a great influence on viscosity as illustrated in FIG. 2 . The viscosity of these systems was almost constant with HAP solids loading equal or below 30 wt % as shown in FIG. 3 . Further increasing the solids loading to 40 wt % dramatically increased the viscosity of the suspensions. As a matter of fact, the highest HAP loading achievable is about 43 wt %. Above that it became difficult to measure rheological properties.
Effect of temperature on gelation properties was also investigated. It is known that temperature up to 93° C. have no effect on the viscosity of xanthan gum solutions. Locust bean gum solution, prepared at 70-80° C., also showed no significant changes in viscosity as the temperature was decreased. K-carrageenan solution, prepared at 70-75° C. in a similar way to locust bean gum, formed a rigid gel upon cooling. Its rheological behavior was investigated as a function of temperature. Temperature dependent viscosity measurements of carrageenan were started at 70° C. and eventually cooled to 20-30° C. in a water jacket of the rheometer.
As shown in FIG. 4 at higher temperature (50-70° C.), the suspension containing 30 wt % HAP and 2 wt % carrageenan had low viscosity values. It formed a gel around 40° C., indicated by the sudden increase of viscosity. Below 40° C., the gel was fractured by applied shear force, resulting in the decrease of viscosity. A 2 wt % carrageenan solution without HAP showed a similar temperature dependence (FIG. 4 ). This thermal gelaton property makes the HAP-carrageenan suspension a good candidate as self-setting bone filling materials. It was fluid-like and injectable above 45° C., and formed a rigid gel at body temperature of 37° C.
Materials Characterization
The microstructure and porosity of HAP-carrageenan pastes were studied by scanning electron microscopy (SEM). These pastes were prepared at 70-75° C. and cross linked in simulated plasma electrolyte solution as described above. They were then cut into small rectangular pieces with rough dimension of 2.5 cm×0.5 cm×0.3 cm. To preserve structures, they were quickly frozen in liquid nitrogen, then dried in vacuum at −12° C. for at least 24 hours. The dimension of each piece was measured using calipers before and after freeze drying to check on the shrinkage. While the samples containing 30 wt % or 40 wt % HAP and 2 wt % carrageenan showed less than 5% shrinkage, a sample containing 10 wt % HAP and 2 wt % carrageenan shrank 10-20%, indicating a structure collapse during freeze drying. The SEM images of 30 wt % and 40 wt % HAP in 2 wt % carrageenan are shown in FIG. 5 . The structure of the 30 wt % HAP contained HAP agglomerates of 5-10 μm, and pores ranging from 5-15 μm throughout the monolith. An increase of HAP loading to 40 wt % produced denser material and reduced pore size to less than 5 μm.
HAP Dissolution By Constant Composition Method
The kinetics of HAP dissolution of HAP-carrageenan pastes was studied by constant composition (CC) techniques. An undersaturated solution containing 0.125 mM CaCl 2 and 0.075 mM KH 2 PO 4 and 0.15M NaCl was prepared by mixing stock solutions of 0.1M CaCl 2 and 0.1M KH 2 PO 4 in 0.15M NaCl. The solution pH was adjusted to 6.5 using 0.1M KOH solution. Nitrogen, saturated with water vapor, was purged through the prepared solution to exclude carbon dioxide. A combination pH electrode (Corning) was used as a probe to monitor solution pH. An amount of 0.083 g of 30 wt % HAP-2 wt % carrageenan paste was weighed and added to the under saturated solution to initiate the dissolution experiment. The solution pH was kept constant by the potentiostatic controlled addition of 0.30M NaCl and 0.007M HCl. The rate of dissolution was calculated from the rate of addition of the acid after correcting for the volumes required to maintain constant pH. For comparison, the dissolution rate of 0.025 g HAP powder, same amount of HAP as in HAP-carrageenan paste, was measured using the same technique [FIG. 6 ]. The CC results indicated both samples have high initial rates, and dissolution slowed down as more and more calcium and phosphate ions accumulated in the solutions. HAP-carrageenan paste had a lower initial dissolution rate than the free HAP powders. As the carrageenan gradually leached out, the HAP-carrageenan paste became loosely attached and acted more like free particles.
Carrageenan Leaching Studies in Simulated Blood Plasma Electrolyte Solutions
Suspensions containing 2 wt % carrageenan and 0 to 40 wt % HAP were prepared at 75° C. They were poured into small weighing dishes and formed blocks upon cooling to 37° C. After weighing each block (about 8 gram ), each block was placed in 20 ml of simulated blood plasma solution at 37° C. Periodically, the solution was collected and replaced with new solution. The HAP powder that was remaining in the solution was separated by centrifugation. The clear solution samples were diluted and mixed with methylene blue. The concentrations of carrageenan were determined by measuring adsorption at 559 nm against a standard calibration curve. The result is shown in FIG. 7 .
Among the paste samples tested, those containing less than 20 wt % HAP were softened and broken down after 24 hours. Therefore, no data was available after this period. At higher HAP loading, the blocks maintained shape. The results indicated that as the HAP solid loading increased, the rate of carrageenan leaching decreased.
In vivo Results
Implants prepared according to the above procedure with carrageenan were placed in an induced bone defect in mice and produced an acute adverse response. Thus, while carrageenan is an attractive candidate material based on physical properties, it was found to lack biological compatibility when formulated as a polymer/ceramic composite. The high dissolution rate of carrageenan may contribute to the adverse response. Although the carrageenan illustrates the desireable physical properties of the invention, it may not be useful in the method of the invention if it is unsuited to implantation in a mammalian body.
EXAMPLE 2
Chitosan Study
Methods
High molecular weight (HMW) chitosan, 1.1-1.6×10 6 D, was purchased from Aldrich Chemical Company, Inc., low molecular weight (LMW) chitosan, 70 KD, was purchased from Fluka Chemie. Chitosans were dissolved in 0.1N HCl and purified before use by precipitation into acetone/water mixture. Hydroxyapatite (HAP), tricalcium phosphate (TCP), Bovine serum albumin (BSA), 5-fluorouracil (5-FU), were purchased from Sigma Chemical Company, and used as received. Phosphate buffered saline (PBS), pH 7.4 was used as a release medium in BSA and 5-FU release experiments.
Preparation of Chitosan-HAP and Chitosan-TCP Suspensions
Solutions containing 0.5-2 wt % of purified chitosan were prepared in 0.1N HCl. Chitosan-HAP or -TCP suspensions were prepared by simple mixing of the ceramic component with chitosan solution. Suspensions containing 20-45 wt % of HAP and 30-50 wt % of TCP were prepared.
Compressive Modulus Measurements
Experiments were performed using Dynamic Mechanical Analyzer equipped with the stainless-steel parallel plate measuring system. Compressive modulus was determined by using a uniaxial, unidirectional compressive deformation. The samples, in the form of cylindrical disks, were held in place initially with a minimal static stress, then the static stress was increased. The response of the sample (static strain) was used to calculate the static compressive modulus.
Release of Model Compounds
The release of 5-FU and BSA from chitosan-HAP or -TCP composites was conducted in PBS, pH 7.4 at 37° C. A cylindrically shaped samples of the composites were cured in a small diameter dialysis tubing. The amount of released compounds was determined by monitoring UV absorption of the release medium at 266 and 280 nm for the 5-FU and BSA, respectively. To maintain sink conditions, samples were transferred into fresh release medium at predetermined time intervals. The release kinetics data were reported as fraction of the total amount released versus time.
Results
In order to obtain chitosan-calcium phosphate composites suitable for the injectable, resorbable scaffolds for bone tissue regeneration, several properties of the composites need to be investigated and optimized. The most important requirements are the following: bio compatibility of the materials and their degradation products, injectability of the polymer-ceramic suspensions, suitable gelation kinetics of the composites, controlled degradation rates, ability to release small and large therapeutic agents and finally osteoconductivity. As a consequence of the above requirements, experiments have focused on the investigation and optimization of the following properties: rheological properties of the suspensions, and water content, porosity, compressive strength, and degradation rate of the cured composites. The ability of the composites to release therapeutic agents was also evaluated.
Chitosan-calcium Phosphate Suspensions: Preparation and Rheological Properties
Chitosan dissolves in diluted acids at pH 2-3 but the pH of the obtained solution may be titrated up to a pH of 6 with no change in polymer solubility. Therefore, chitosan-ceramic suspensions may be prepared at a wider pH range, i.e. 2-6. The pH of chitosan solution is important since it affects the solubility of the calcium phosphate phase of the composite.
Rheological properties of chitosan solutions and chitosan-calcium phosphate suspensions were investigated as a function of chitosan concentration, molecular weight, content and type of a calcium phosphate phase (HAP or TCP). As illustrated in FIG. 8, chitosan-HAP suspensions containing up to 40 wt % of HAP phase exhibited viscosities and flow suitable for injectable bone paste applications.
Compressive Modulus
Compressive modulus is a measure of the resistance of the sample to compression and is an indicator of stiffness or rigidity. Relative compression moduli were determined to assess the changes in mechanical properties of the polymer-ceramic composites resulting form the gelation of the polymeric component. The compressive moduli were determined for a series of polymer-ceramic composites differing in composition in terms of ceramic (HAP or TCP) as well as polymeric components (LMW or HMW chitosan). Results are presented in FIGS. 9 and 10. The effect of solids loading, i.e., the amount of ceramic phase in the composite, on the compressive modulus of HMW chitosan-HAP composite is illustrated in FIG. 9 . Composites with higher solids loading, 40 wt %, demonstrated higher relative compressive modulus as demonstrated by a steeper slope of the stress strain curve. A similar trend was observed for the chitosan TCP composites. The effect of the ceramic phase type is illustrated in FIG. 10 . Composites containing HAP demonstrated higher relative compressive moduli than composites containing TCP. The trend was similar for both chitosans HMW and LMW (results not shown). The results of compressive modulus studies clearly demonstrated that the chitosan-calcium phosphate composites in a gelled state maintain mechanical integrity in contrast to the flowable, injectable properties of the corresponding suspensions.
Release of Model Compounds
Different therapeutic and osteoconductive agents may be incorporated into the thermally reversible polymer-ceramic composites as needed. Examples of therapeutic agents include antibiotics for the local treatment of possible infections, anticancer agents for the site specific treatment of bone tumors. Examples of osteoconductive agents include growth factors and bone morphogenic proteins. In order to asses the possibility of using our novel polymer-ceramic composites as delivery vehicles for therapeutic and/or osteoconductive agents we have investigated the release of model low and high molecular weight compounds.
An anticancer agent, 5-fluorouracil (5-FU) was used as a model low molecular weight compound and bovine serum albumin (BSA) was used as a model macromolecule. The results of the release experiments are presented in FIGS. 11 and 12. In FIG. 11 the effect of two calcium phosphate ceramic phases are compared, showing a small rate advantage to HAP over TCP. As illustrated in FIG. 12 the release of 5-FU and BSA demonstrated different kinetics. While 5-FU released from the chitosan-TCP composite within 10 hours, BSA release was much less rapid and lasted for 40 hours. These results may be explained by the differences in the effective size of the releasing molecules. BSA, being a macromolecule demonstrated slower release kinetics due to the lower effective diffusion coefficient within the polymer-ceramic matrix. The release results demonstrated that chitosan-calcium phosphate composites may be used as a matrix for the release of therapeutic agents and proteins such as growth factors and bone morphogenic proteins.
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The present invention provides a composition which comprises a polymer or polymer solution that forms a gel under controlled parameters and a ceramic matrix, the composition being fluid under non-physiological conditions and non fluid under physiological conditions. Polymers may be resorbable or non-resorbable, natural or synthetic and the solution aqueous or non-aqueous. Preferred polymers are poly saccharides, polyamides or polyamino acids, however any polymer or polymer solution that is biologically compatible and that is fluid under nonphysiological conditions and increases in viscosity under physiological conditions is suitable.
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CROSS-REFERENCE TO RELATED APPLICATION
Not applicable.
STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
BACKGROUND OF THE INVENTION
The present invention relates to plumbing valves such as faucets. More particularly it relates to such valves which are controlled by a joystick type handle control.
A wide variety of plumbing control valves are known which use a single lever handle to control volume and mixing. Typically the handle extends through the top or front of a valve housing with its inner end linked to sliding and/or rotating plates or other control structures. The outer end of the handle is designed to be gripped by the consumer. See e.g. U.S. Pat. Nos. 1,798,530, 2,850,042, 3,512,547, 3,548,878, 3,693,660, 4,357,957, 4,916,966, 5,095,934, 6,209,581 and 6,286,808.
However, a problem with many of these designs is that pressure on the control handle during actuation can eventually cause the handle connection to loosen, which can allow the handle to inadvertently actuate or wobble. Further, over time some of these devices require a relatively large force to cause movement of the valve components, which can expedite degradation of valve internal components. Even where this is not the case, many of these designs are undesirably susceptible to wear and tear.
Still other of these designs do not effectively preclude environmental water, soap and dirt from entering the valve. Again, this can adversely affect performance.
In other developments, there have been some attempts to provide such control handles which mimic the aesthetic appearance and feel of an aviation or video game joystick. However, existing prior art designs suffer from one or more deficiencies (e.g. those noted above).
In still other developments there have been attempts to mount faucets in hidden enclosures associated with lavatories. For example, Kohler Co. markets a Purist™ bathroom cabinet in which the outlet for its faucet is integrated inside the cabinet. However, that system uses a conventional control handle to control outlet flow.
Thus, a need still exists for improved single handle plumbing valves, particularly those which present a joystick-type feel and appearance and/or which are capable of being integrated into cabinets and other box-like housings.
SUMMARY OF THE INVENTION
In one aspect the present invention provides a faucet that has a housing, a first inlet port for supplying water to the faucet, an outlet port for delivering water from the faucet, a control valve suitable to control the flow of water from the inlet port to the outlet port, a lever linked to the control valve for controlling the control valve, a joystick handle linked to the lever so as to permit relative axial movement there between, and a biasing member positioned outside the housing between the lever and joystick so as to resiliently bias the joystick away from the control valve. Typically, there is also a second inlet port for supplying water to the faucet which has a different water temperature than water supplied to the first inlet port, wherein the control valve controls both volume of water delivered out the outlet port, and the mix of water delivered out the outlet port deriving from the first inlet port versus the second inlet port.
In preferred forms the joystick handle has a domed inward end which rides against a complementary recess in a cover element, the cover element has an essentially central aperture through which extends at least part of the domed end, and the lever has an inward end which has a ball.
Some embodiments of the invention are particularly suitable to be mounted in a box with the handle (and possibly a portion of an outlet nozzle) projecting out a front of the box. The box could be a compact counter top mounted box, or could be a cabinet having storage shelving.
In another aspect the invention provides a faucet which has a housing, a first inlet port for supplying water to the faucet, an outlet port for delivering water from the faucet, a control valve suitable to control the flow of water from the inlet port to the outlet port, a lever linked to the control valve for controlling the control valve, a joystick handle linked to the lever, a ball positioned along the lever for movement there along, and a biasing member positioned outside the housing between the ball and joystick so as to resiliently bias the ball towards the control valve. Again, these principles can be applied to a mixing valve with multiple inlets and a valve that controls both volume and water temperature.
In preferred forms there is a sliding disk between the ball and housing that slides as the lever is tilted, as well as a bearing positioned between the housing and sliding disk. Most preferably the bearing is formed of an acetal copolymer.
In other preferred forms there is a set screw axially fixing the lever to the joystick, the faucet is in the form of a lavatory spout suitable to be mounted on a counter top, and the ball has a cavity housing a coiled spring.
One important advantage of the present invention is that the spring provides a resilient loading to the joystick, or from the joystick. Further, when a sliding disk is used to cover the connection between the handle, the lever and the control valve, the disk can be provided with a self-lubricating bearing. In any event, it helps seal out water, debris and cleaning solutions.
The resiliency of the joystick connection also minimizes wear on the internal moving parts, while providing an aesthetically pleasing feel. Importantly, the location for a spring outside the main housing facilitates assembly and maintenance.
Another advantage of the resilient connection is that it reduces the likelihood of cracking the cabinet or other associated supporting box. For example, the associated mirror of the cabinet may be somewhat fragile. The extra give provided by the spring is an important safeguard in reducing excess pressure.
Yet another advantage of the present invention is that when these faucets are used with aesthetically pleasing cabinet and other box housings, with appropriate positioning of an outlet nozzle a user can only see the joystick control and an exiting water stream. Particularly where the nozzle creates a laminar flow, this creates a highly desirable aesthetic appearance.
These and still other advantages of the present invention will be apparent from the detailed description which follows and the accompanying drawings. Hence, the of the faucet. The sides 18 of the cabinet can be in the form of swing-out hide-away shelves.
Faucet 14 includes a front 20 , which can be part of cabinet 16 (e.g. a mirrored front surface of cabinet 16 ) or can otherwise be part of a faucet housing. A outlet spout 22 is connected to the faucet 14 , and a mixing valve cartridge 24 is in fluid communication with spout 22 .
The precise mixing valve used is not critical provided that it can be controlled by joystick movement. For example, the mixing valve of U.S. Pat. No. 6,209,581, incorporated herein by reference, could be used to control water flow from hot and cold inlets to the outlet spout 22 . Alternatively, one could select other commercial ceramic mixing valves such as the Kerox Model GN-40A, which is advertised to be suitable for use with joystick control.
In any event, the cartridge should be able to accept a conventional hot water inlet connection 26 and cold water inlet connection 28 , and be connectible to a mixed water outlet tube 30 . Further, the control disks or other structures of the valve should be suitable to be activated by pivoting (or other movement) of the stick lever 32 . Further, in accordance with the present invention, a joystick type faucet handle 34 is then mounted to stick lever 32 (in this embodiment to permit relative axial movement there between).
A cover 42 is positioned between the joystick handle 34 and front 20 , and a biasing element 38 (in the form of a spring) is positioned outside front 20 between joystick handle 34 and stick lever 32 . Biasing element 38 biases handle 34 outward, and thus domed skirt 40 attached thereto against a corresponding recess in cover 42 . following claims should be looked to in judging the full scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a bathroom storage cabinet and adjacent lavatory, where a plumbing valve of the present invention has been integrated therewith;
FIG. 2 is a fragmentary cross-sectional view taken generally along line 2 - 2 of FIG. 1 ;
FIG. 3 is an enlarged sectional view of detail portion 3 - 3 of FIG. 2 ;
FIG. 4 a view similar to FIG. 1 , but with the FIG. 1 cabinet replaced by a different more compact counter top mountable housing;
FIG. 5 is a schematic illustration of how a joystick of the present invention controls water flow and temperature;
FIG. 6 is an exploded perspective view of the FIG. 4 faucet, excluding the spout;
FIG. 7 a perspective view of a third embodiment, in the form of a faucet with a joystick control, positioned adjacent a lavatory;
FIG. 8 is an exploded perspective view of the faucet of FIG. 7 ;
FIG. 9 is a cross-sectional view taken along line 9 - 9 of FIG. 7 ; and
FIG. 10 is a cross-sectional view similar to FIG. 9 but with the faucet handle in a different “on” position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIGS. 1-6 , there is shown a sink 12 and a cabinet 16 having a faucet 14 associated therewith. The internal central portion of the cabinet 16 can contain plumbing connections and most of the parts
Biasing element 38 is shown as a coil spring. However, other biasing structures are possible such as leaf springs, spring washers, elastomeric materials, and other resilient compressible elements such as a gas diaphragm.
There is also a gasket 44 between front 20 and cover 42 . Cover 42 also includes an approximately central aperture 46 through which extends at least part of domed skirt 40 .
Other elements include O-ring 48 , collar 50 , spring washer 52 , and nut 54 . Nut 54 is threadably engaged with casing 56 to provide an outer limit for mixing valve cartridge 24 , among other things, and screws 58 fix cover 42 to casing 56 .
Split nut 60 provides an inside limit for handle 34 . O-ring 62 reduces or eliminates any wobble in handle 34 and provides the user with a more positive control. Casing 56 can also include couplings (not shown) which connects inlet connections 26 and 28 , and outlet tube 30 , to corresponding ports on mixing valve cartridge 24 .
As best seen in FIG. 6 , front 20 can include a mirrored surface 64 and back plate 66 , as well as corresponding bracket 68 , with shoulder screws 70 and springs 72 which connect to casing 56 to further support faucet 14 , and provide stress relief on front 20 .
Mixing valve cartridge 24 can include a triangular opening 74 , which allows faucet handle 34 to control temperature and flow. As suggested by FIG. 5 , it is preferred that the mixing cartridge be such that a central upper stick position will be the off position. As the stick moves forwardly/downwardly, the volume increases. As it moves to the left the temperature of the resulting water increases. As it moves to the right the temperature decreases. Of course, with appropriate selection of a different mixing valve, rotational movement alone, and/or various combinations of pivoting and rotation could control the valve.
In the alternative embodiment of FIG. 4 there is sink 82 and faucet 84 in a more compact housing arrangement 86 which is counter mounted. Apart from this, faucet 84 is similar to faucet 14 except that spout 22 here is preferably positioned somewhat differently. Thus, the “box” need not be a medicine cabinet or other large cabinet type structure.
In the embodiment of FIGS. 7-10 there is shown a third stand-alone faucet embodiment. There is a sink 92 and a faucet 94 mounted on the rear of the sink 92 .
Faucet 94 has an outer housing 96 and an outlet spout 98 . Mixing valve cartridge 124 can be the same as mixing valve cartridge 24 in the other embodiments. A joystick type handle 100 is connected to a stick 132 .
Here, instead of the spring biasing the handle away from the lever, biasing element 104 biases a ball 106 against sliding disk 110 . Biasing element 104 can be a coil spring as shown, although other resilient members are possible such as leaf springs, spring washers, resilient members comprised of elastomeric materials, or other compressible elements such as a gas diaphragm, and other biasing elements.
There is also a bearing 108 contacting both the ball 106 and the sliding disk 110 . Bearing 108 can have an outer surface 112 complementary with an inner surface 114 of sliding disk 110 . Bearing 108 can be made of an acetal copolymer, such as Celcon®, which allows bearing 108 to have excellent wear resistance, and have high flexural fatigue strength, toughness and creep resistance. Bearing 108 and sliding disk 110 slidingly engage housing 96 as faucet handle 100 is actuated. Set screw 116 threads into handle 100 and is compressed against stick 132 .
Nut 154 is threaded into housing 96 . Couplings 118 allows connection between hot and cold inlet lines ( 120 , only one shown) to corresponding ports on bottom of mixing valve cartridge 124 . Depending on the position of faucet handle 100 , water is discharged out the bottom discharge outlet of mixing valve cartridge 124 and outlet spout 98 . O-ring 122 seals the mixed water from leaking out between couplings 118 and outlet spout 98 .
Here the resilience is between the handle 100 and the ball 106 . This is particularly important as ball 106 holds the sliding disk 110 in place while still permitting easy sliding so as to cover the opening in the valve regardless of position.
While the preferred embodiments of the present invention have been described above and/or depicted in the drawings, the present invention can be further modified within the spirit and scope of this disclosure. Hence, the claims should be looked to in order to judge the full scope of the invention.
INDUSTRIAL APPLICABILITY
The present invention provides faucets having joystick type controls with improved characteristics.
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Faucets are provided with joystick type control handles. The joysticks are provided with springs outside the main valve housing either between the joystick handle and lever stick, or between the joystick handle and an associated ball. In the latter case the ball retains a sliding disk.
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Priority for this invention is claimed under 35 USC 119 (e) based on application Ser. No. 60/109,521 filed on Nov. 23, 1998
FIELD OF INVENTION
This invention pertains to a lighting device to be installed on safety helmets and the like.
BACKGROUND OF THE INVENTION
There are a number of safety lighting devices presently being used in connection with recreational activities such as bicycling and work activities such as highway repair as exemplifies by the following:
U.S. Pat. No. 4,231,079 shows a wearing apparel such as a hat that contains a series of LEDs, (light emitting diodes), located in perforations in the hat. A battery supplies power Control circuitry interconnects the battery and diodes to energize the diodes sequentially. A clock emits pulses for an electronic counter, a decoder takes the counter input and controls which diodes are to be sequentially illuminated.
U.S. Pat. No. 4,665,568 is an example of a nightime safety headgear such as a soft cap with a visor and a molded plastic unit supporting two antenna protrusions, each having three LEDs and a single safety light centered in the plastic unit in front of the cap. The LEDs are powered by an electrical system molded directly into the unit and powered by a 3 volt battery. A button on top of the cap activates an On-Off switch.
U.S. Pat. No. 4,760,373 illustrates a motorcycle helmet containing an automatic brake light which shines when the brake pedal is depressed. A transmitter is attached to the motorcycle, and a receiver which activates the light is attached to the helmet. A transmitter encoder and a receiver decoder prevent spurious sources of radio frequency from activating the receiver. A code card is used to guarantee that both encoder and decoder are in synchronization.
U.S. Pat. No. 4,891,736 depicts a rigid helmet having a lens whose surface is flush with the surrounding surface in close proximity to the lens. Three signal lights shine through and about the lens for giving tail, brake and directional directions to following motorists at eye level. The helmet may be equipped with a cable coupled to the cycle on which the wearer rides or the helmet may be telemetered to the cycle by a radio module in the helmet.
U.S. Pat. No. 5,040,099 is a motorcycle helmet with a rearward facing auxiliary brake lamp fastened to the cycle, spaced from and connected optically or sonically to a motorcycle brake lamp. The auxiliary lamp is activated by the illumination of the brake lamp.
U.S. Pat. No. 5,357,409 depicts an illuminated safety helmet that has a protective core and a plurality of LEDs with at least an intensity of 1000 mcd is placed around the core for sequential lighting. The control circuitry includes an oscillator with a ring counter and transistors enclosed in a housing. A power source of series connected batteries activates the control circuitry and LEDs. The housing is electrically connected to the LEDs and is removably attached to the protective core. An impact resistant shell or a skin of stretchable material is disposed in the internal or external surface of the protective core.
U.S. Pat. No. 5,485,358 teaches a universal LED safety light for head wear. The LEDs are mounted on a flexible plate. The plate is one of the straps of a length adjustable belt provided at the rear of the cap. The strap is stitched to the rear of the cap an dused for length adjustment. A circuit board containing a battery, an integrated circuit for triggering the LEDs and an On-Off switch is secured to the cap with “Velcro” ™.
U.S. Pat. No. 5,544,027 illustrates an LED Display for a protective helmet which can either be added to existing helmets or incorporated in a newly manufactured helmet. The LEDs are coupled to a 9 volt battery in the helmet or a bicycle mounted generator via a cord. The LEDs can be lit simultaneously or sequentially by a computer chip.
U.S. Pat. No. 5,667,294 shows a strip sport light with a center strip and two arm strips with multiple light sources for illumination of a center strip and blinking of the side strips dependent on the position of the switch. The center strip contains an electronic printed circuit board and a three step push button switch. The strip sport light may be mounted on a bicycle helmet or on a users head or waist.
The prior art shows various displays of lights or LEDs to be arranged on a helmet or on strips to be placed on a users head or other wearing apparel. The lighting displays are used for safety and ornamental purposes. Whatever the type of apparatus the minimum circuitry required is a PCB. In general however, there are other elements such as 3 way switches, clocks, a plurality of batteries or a nine volt battery, counters, coders, decoders, etc. While these devices have greater flexibility, in that lighting arrangements can be made for steady state, blinking and sequential lighting as well as variable lighting rates, they are considerably more expensive and cumbersome because of the additional circuitry. Another factor to be considered is the problem of repair if one or more of the elements becomes defective.
Accordingly it is an objective of this invention to design a safety and ornamental lighting device to be used on helmets and the like that is simpler in construction.
It is also an object of this invention to provide a lighting device that is less costly for the potential purchaser.
It is a further object of this invention to design a lighting device for a helmet and the like which is lighter and more comfortable to wear.
It is additionally an object of this invention to design a device that is attractive, efficient and less likely to need repair.
SUMMARY OF THE INVENTION
This invention provides an LED display for a helmet or the like wherein the only circuitry involved is an internal power source such as a single 3-6 volt battery, an On-Off switch and wiring to a plurality of LEDs, specially designed for blinking.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the helmet and an LED arrangement.
FIG. 2 is a sectional view taken on line 1 — 1 through the switch and battery and some of the LEDs.
FIG. 3 is a schematic showing the arrangement of the LEDs.
FIG. 4 is a side view of the helmet.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a perspective view of a conventional helmet 1 having an array of light emitting diodes 2 (LEDs) protruding through perforations 3 in a colored plastic liner 4 adhesively attached and covering substantially the surface of the helmet except for a narrow integral segment 5 that extends circumferentially around the base of the helmet. The LEDs are affixed to the liner and are varied in color such as red, green or yellow. They are arranged symmetrically in 4 parallel rows with 6 LEDs in each row. This arrangement is by way of illustration and other designs could be used as well. For example, more or less LEDs could be used. The rows need not be parallel and instead of being symmetrical the LEDs could be staggered. The LEDs are of the blinking type made by “Mouser” and have a forward voltage of 3-6 volts. As shown in FIG. 2, on one side of the helmet toward the rear and below the endmost row of LEDs is an On-Off rocker switch 6 . The switch is in the form of a disk 7 which is seated in a square casing that nests in a cut out of the helmet so that the casing is flush with the outer surface of the helmet and the disk is tilted so as to be slightly above the surface of the helmet. At the bottom side of the switch are prongs 8 with wires 9 soldered thereto. Aligned on the opposite side of the helmet is a circular 3-6 volt battery 10 embedded in the helmet. The battery is held in place by an overlapping metal ring 11 . In the region of the battery a cutout in the liner is made and a plastic cap 11 a with a skirt 11 b fits snugly over the battery with the top of the cap projecting slightly above the periphery of the liner. Affixed to the battery and extending across its top side is a filament 12 . This filament serves as the positive connection. A prong 8 at the bottom side of the battery in electrical contact with the positive connection has one of the wires from the switch soldered thereto. The other wire from the switch is soldered to another prong at the bottom side of the battery and serves as the negative connection. The wire from the positively linked prong is electrically joined to the anode of the endmost LED at the rear of the helmet and the wire from the negative connection is electrically joined to the cathode. Additional wiring as shown in FIG. 3 of the schematic, links all the LEDs in parallel, with the switch and battery in series with the LEDs. The battery is generally of the Lithium type and the wire is 16 gauge. In operation turning the switch to the On position will produce a blinking illumination of the helmet that has sufficient intensity to be seen from a distance of about 50-100 feet. The LEDs have a life of about 3 hours steady use. Instead of using multi-colored LEDs, dual colored LEDs could also are used.
It should be understood by those skilled in the art that various changes and variations can be made in the Safety Lighting Device of this invention without departing from the scope of the i invention as defined by the appended claims.
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A lighting device for a safety helmet or the like used for recreational and industrial purposes wherein a plurality of blinking LEDs are disposed on the outer surface of the helmet. The only circuitry needed is a 3 volt battery, an On-Off Switch and wiring for interconnecting the LEDs
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of copending International Application No. PCT/EP01/14117, filed Dec. 3, 2001, which designated the United States and was not published in English.
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to an apparatus for pressing items of clothing, in particular shirts, having an inflatable body and devices for inflating the inflatable body with air, the inflatable body being internally subdivided into a plurality of cavities by partition walls.
The item of clothing or shirt that is to be pressed is tensioned from the inside by the inflatable body. As a result, the creases are removed. To improve the pressing result, the shirt is usually pressed, as in the case of conventional steam irons, under the action of moisture and heat. For such a purpose, the shirt is fitted in the damp state onto the inflatable body, and fixed, if appropriate, at the collar and button strip, and the inflatable body is inflated with heated air. As a result, the shirt is dried under tensioning. If the enclosure of the inflatable body is of air-permeable configuration, then it is also possible for the heated air to flow through the shirt and, thus, accelerate the drying operation.
An apparatus of the type mentioned in the introduction is known, for example, from U.S. Pat. No. 3,165,244 to Martin. This document describes an inflatable body that is subdivided into a plurality of chambers, it being possible for the individual chambers to be inflated, through separate lines, by a fan and for the supply of air into one chamber to be restricted in favor of the supply of air into the rest of the chambers. This makes it possible to achieve different pressures in the chambers. Disadvantageously, however, a high outlay is required for the lines and the valve that are necessary.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an apparatus for pressing shirts, having a subdivided inflatable body that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that provides specifically different conditions in the various cavities of the inflatable body with low outlay and high repetition accuracy.
With the foregoing and other objects in view, there is provided, in accordance with the invention, an apparatus for pressing items of clothing, including an inflatable body having partition walls and being internally subdivided into a plurality of cavities by the partition walls, the cavities including at least one indirectly inflated cavity and at least one adjacent cavity, devices for inflating the inflatable body with air communicating with the inflatable body, and a partition wall of the walls separating the at least one indirectly inflated cavity from the at least one adjacent cavity and passing air therethrough counter to a flow resistance, the indirectly inflated cavity being inflated with air exclusively through the partition wall. Preferably, the items of clothing are shirts.
On account of the flow resistance of the air-permeable partition walls, it is possible for the indirectly inflated cavities to be inflated with a time delay. As a result, the shirt that is to be pressed can be moved into an optimum position, in the first instance, at the beginning of the tensioning operation.
If air can escape through the enclosure of an indirectly inflated cavity, it is, additionally, possible, in the stationary inflated state, to achieve different pressures in the cavities. To achieve a fold-free pressing result, the shirt that is to be pressed can, thus, be tensioned to differently pronounced extents in a specific manner in different directions.
Advantageously, the partition walls and/or the enclosures of the cavities are produced from a textile material, it also being conceivable to use air-permeable sheet materials. The air permeability of the individual partition walls and/or enclosures, and, thus, the conditions in the various cavities, can, thus, be set in a particularly straightforward and cost-effective manner by selection of a certain textile material or, generally, of a flexible material with defined air permeability. Furthermore, the selection of a certain textile material or air-permeable material reliably establishes the conditions for the different cavities over a long period of time.
A framework disposed within the inflatable body can support, in particular, the enclosures of the cavities or the chambers in which the pressure prevailing is higher than in the rest. It is, thus, possible for the outer shape of the inflatable body to be influenced more strongly because the supported chambers can exert a higher force in the outward direction. In the case of a shirt-form inflatable body, this is advantageous particularly on the sides of the trunk because it is, thus, possible for the trunk section to be tensioned into a flat form by the outwardly directed lateral pressure and for a shirt fitted onto the inflatable body to be pressed corresponding to its cut and, thus, in more fold-free manner. The frameworks or bodies for supporting individual chambers within the inflatable body need not necessarily be rigidly connected to the shirt-pressing apparatus; it is also possible for them to be fastened exclusively on the enclosures of the inflatable-body cavities or of the inflatable body. The supporting bodies, which are, thus, fastened in a floating manner, can better follow the movements of the inflatable body and are advantageously of particularly lightweight configuration. Such non-rigidly fastened frameworks or bodies for supporting individual chambers may be used, for example, in the arm sections or in the top region of the inflatable body.
If the chambers are crashed or dropped steeply over a surface, it is possible for the orientation of this surface to influence the shape of the inflatable body in the inflated state. The orientation of this supporting surface, furthermore, can be used to compensate for external influences on the shape of the inflatable body. Such an influence may come, for example, from a button-strip clamp, which is disposed on the front side of the inflatable-body trunk section and fixes the button or buttonhole strip of a shirt fitted onto the inflatable body and, thus, subjects the inflatable body to a force either directly or indirectly through the shirt. This force may result in the inflatable body and/or the sections thereof being deflected and, thus, in folds in the shirt. To counteract this, the surfaces for supporting the laterally disposed chambers are turned about the vertical axis in the direction of the button-strip clamp.
In accordance with another feature of the invention, the indirectly inflated cavity defines an air-permeable enclosure.
In accordance with a further feature of the invention, the partition wall is of a substantially air-impermeable material and has a valve through which air can flow.
In accordance with an added feature of the invention, the inflatable body is shirt-shaped and has sleeve sections and a trunk section with narrow sides, and defines two side cavities on the narrow sides beneath the sleeve sections, the two side cavities defining side cavity enclosures and being inflated directly, the framework is disposed between the two side cavities, the side cavity enclosures, in an inflated state thereof, are supported on the framework, and the interior, outside the side cavities, is inflated with air exclusively through the partition wall to the side cavities.
From the cavities supplied directly with air or the cavities with relatively high pressures, it is possible to direct air, through a substantially flow-resistance-free connection, to locations at which a larger quantity of air is advantageous for the purpose of achieving a better pressing result. This may be, in particular, at those locations of the shirt to be pressed at which the fabric is present in a number of layers or drying is obstructed by additional applications. For such a purpose, the air can be directed with greater intensity into cavities located beneath the shirt sections that are more difficult to dry, or to direct air-supply devices that can direct the air out of the inflatable body and, from the outside, against the shirt that is to be pressed. Such direct air-supply devices may be disposed, for example, in the collar or cuff region of the shirt.
In accordance with an additional feature of the invention, the inflatable body has shoulder sections, the inflatable body defines further cavities in at least one of the sleeve sections and the shoulder sections, the further cavities being in substantially flow-resistance-free connection with the side cavities.
In accordance with yet another feature of the invention, there is provided at least one direct air-supply device directing air out of the interior of the inflatable body and against a shirt fitted onto the inflatable body from outside the shirt, the side cavities being in substantially flow-resistance-free connection with the at least one direct air-supply device.
In accordance with yet a further feature of the invention, the inflatable body has vertical axis, the trunk section is substantially flat and defines a plane, a means for fixing a trunk section of a shirt fitted onto the inflatable body, the fixing means running parallel to the vertical axis, and the framework has surfaces for supporting the side cavity enclosures, a surface normal of the surfaces being inclined with respect to the plane of the trunk section.
In accordance with yet an added feature of the invention, the inflatable body has vertical axis, the trunk section is substantially flat and defines a plane, a clamping-in device runs parallel to the vertical axis and fixes a trunk section of a shirt fitted onto the inflatable body, the framework has surfaces for supporting the side cavity enclosures, a surface normal of the surfaces being inclined with respect to the plane of the trunk section.
The crosspieces for reducing the airflow may be disposed, in particular, in the directly inflated chambers, in which a higher temperature is usually achieved. An excessively high temperature may lead to premature drying of shirt sections that come into contact therewith. As a result, energy is dissipated unnecessarily because the pressing operation is only terminated when the shirt is completely dry. The crosspieces can help influence the dissipation of energy to the various shirt sections so as to achieve more uniform drying of the various shirt sections and, thus, lower energy consumption. The divided-up regions with reduced airflow may be provided, in particular, at the locations at which, with an unobstructed airflow, the inflatable body would be overheated to an excessively pronounced extent. The heat insulation in such regions of reduced airflow increases as the flow rate of the air in these regions decreases.
In accordance with yet an additional feature of the invention, there is provided air-guiding crosspieces disposed within the side cavities and at least partly dividing up regions within the side cavities to reduce air flow in the regions.
In accordance with again another feature of the invention, the regions divided up by the crosspieces have only one inlet opening out into an interior of the side cavities.
In accordance with again a further feature of the invention, there is provided at least partially air-permeable wall, the regions divided up by the crosspieces being closed and separated from an interior of the side cavities by the at least partially air-permeable wall.
The enclosures of the indirectly inflated cavities and of the inflatable body may be connected, for example, by snap fasteners or zip fasteners, the snap fasteners advantageously being used in the region of the underside of the sleeves and zip fasteners advantageously being used in the region where the sleeves start.
In accordance with again an added feature of the invention, the inflatable body defines an enclosure and the directly inflated cavity defines an enclosure releaseably connected to the enclosure of the inflatable body.
In accordance with again an additional feature of the invention, the directly inflated cavity defines an enclosure releaseably connected to the air-permeable enclosure.
In accordance with a concomitant feature of the invention, the inflatable body defines an enclosure, the directly inflated cavity defines an enclosure and the enclosure of the directly inflated cavity is connected in at least one of punctiform and linear fashion to the enclosure of the inflatable body.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an apparatus for pressing shirts, having a subdivided inflatable body, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical cross-sectional view of an apparatus for smoothing shirts according to the invention; and
FIG. 2 is a cross-sectional view of a horizontal cross-section of the apparatus of FIG. 1 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a shirt-pressing apparatus having a bottom part 11 with a shirt-form inflatable body 18 mounted thereon, a fan 9 with an integrated heating device being accommodated within the bottom part 11 to make possible inflation of the inflatable body 18 with heated air. The enclosure 4 of the inflatable body 18 is of an air-permeable textile material.
In the interior of the inflatable-body enclosure 4 , a framework 8 is fastened on the bottom part 11 . An air-supply device 12 with air inlets 15 and air outlets 16 is disposed at the top of the framework 8 , to make possible direction of heated air out of the inflatable body 18 and, from the outside, directly onto the collar of a shirt fitted onto the inflatable body 18 .
Also disposed within the inflatable-body enclosure 4 are two side chambers 1 , on both sides of the framework 8 . The enclosures 2 of the side chambers 1 are, likewise, made of an air-permeable textile material. The side chambers 1 extend over the entire height of the trunk section of the inflatable body 18 and project, in part, into the sleeve sections of the inflatable body 18 . Those sections of the side chambers 1 that project into the sleeve sections may have a higher degree of air permeability to achieve a larger air stream into the sleeve sections. For example, it is possible, for such a purpose, for the enclosures 2 of the side chambers 1 , in particular, on the outwardly directed end surfaces, to have a greater degree of air permeability and to have openings or to be provided with nozzles.
The fan 9 is connected to the side cavities 1 through an air channel 10 that leads from the bottom part 11 into the framework 8 , divides up at the bottom of the framework 8 and has two air outlets 17 , which each project through the two side parts of the framework 8 . The side cavities 1 each have air inlets at the bottom, which are connected to the air outlets 17 of the air channel 10 , and air outlets at the top, which are connected to the air inlets 15 of the air-supply device 12 .
During operation, it is, thus, only the side cavities 1 that are inflated directly with heated air by the fan 9 , the air flowing from the side cavities 1 , on one hand, through the air-permeable enclosure 2 into the inflatable body 18 and, on the other hand, through the top openings into the air-supply device 12 . From the inflatable body 18 , the heated air flows through the air-permeable enclosure 4 to the shirt to dry the shirt. The air directed into the air-supply device 12 is discharged, again, through the air outlets 16 , the quantity of air that flows through the air-supply device 12 being influenced by the flow resistance of the air outlets 16 and/or other restricting devices within the air-supply devices 12 .
The air flows from the fan 9 , virtually without resistance, into the side cavities 1 and from there, on one hand, counter to the flow resistance of the enclosure 2 , into the cavity 3 of the inflatable body 18 and, on the other hand, counter to the flow resistance of the air outlets 16 and/or other restricting devices, into the air-supply device 12 . In the stationary inflated state, the pressure distribution within the cavities 1 , 3 is determined by the flow resistances at the transitions from the side cavities 1 to the interior 3 of the inflatable body and into the air-supply device 12 and/or when the air flows out through the inflatable-body enclosure 4 . The flow resistances of the enclosures 2 , 4 depends on the textile material used and on the enclosure surface and may, advantageously, be set such that, during operation, the air pressure in the side chambers 1 is considerably higher than in the rest of the interior 3 of the inflatable body 18 . For example, it is possible to set a positive pressure of from 4 to 6 mbar in the side cavities 1 and a positive pressure of from 1 to 3 mbar in the inflatable-body interior 3 .
In the inflated state, the side cavities 1 are supported against the framework 8 and force the enclosure 4 of the inflatable body 18 outward at the locations at which the enclosure 2 of the side cavities 1 butts against the enclosure 4 of the inflatable body 18 , the enclosure 4 of the inflatable body 18 being subjected to a higher force at these locations, in particular, on account of the higher pressure in the side chambers 1 . In particular, the enclosure 4 of the inflatable body 3 is forced outward laterally beneath the arm sections in the trunk region and upward in the shoulder region. It is, thus, possible for the trunk region of the inflatable body 18 to be converted into a flat form, which better corresponds to the shirt form and, thus, gives a pressing result with fewer folds.
Furthermore, crosspieces 5 are disposed in the side chambers 1 to prevent excessive heat dissipation from the inflatable body 18 in the region of the side cavities 1 . With the aid of vertically running crosspieces 5 , the air flowing out of the air outlets 17 is directed upward into the shoulder region of the side chambers 1 and the sleeve regions of the inflatable body 18 . In addition, the crosspieces 5 divide up into a number of sections and chambers 6 , 7 in which the air flows at a slower rate and/or is substantially at rest and gives rise to thermal insulation. This is advantageous particularly in the case of those locations of the enclosures 2 of the side cavities 1 that are located opposite the air outlets 17 because, without the crosspieces 5 , the air would come into direct contact with this location and would heat it to an excessively pronounced extent. A chamber 7 , in which an air cushion that is substantially at rest ensures thermal insulation, is, thus, provided at this location. In addition, regions 6 are divided up in the side cavities 1 beneath the shoulder regions, in the vicinity of the framework 8 on the inside and beneath the arm extensions on the outside, the regions 6 only having an inflow opening at their top ends and having a relatively small air flow prevailing therein.
The aim of the heat insulation precisely in the inflow region of the side cavities 1 is to set the heat dissipation at the various locations of the inflatable-body enclosure 4 such that a damp shirt fitted onto the inflatable body advantageously dries simultaneously at all the locations. Otherwise, the first-dried regions would be unnecessarily subjected to the action of warm air and energy would, thus, be used up unnecessarily. For example, without heat insulation, the side chambers 1 would be heated to a particularly pronounced extent in the inflow region at the bottom and a shirt fitted onto the inflatable body would dry too quickly on the sides at the bottom. With the aid of the crosspieces 5 , the heat dissipation, which is reduced at these locations, can, instead, be directed into the regions further away.
The air-supply device 12 is connected directly to the side cavities 1 , which are subjected to a relatively high pressure, to make possible for the collar of a wet shirt fitted onto the inflatable body to be better dried by having air flowing directly against the collar, the collar usually including a number of layers and, for this reason, being more difficult to dry. The air-supply device 12 , around which the turned-up collar is positioned, has measures for fixing and clamping the turned-up collar.
FIG. 2 shows a horizontal section through the shirt-pressing apparatus according to the invention. Disposed at the front, in the chest region of the inflatable body 18 , is a button-strip clamp 14 that serves for fixing the button or buttonhole strip of a shirt fitted onto the inflatable body. The button-strip clamp 14 is fastened on the bottom part 11 and extends substantially over the entire height of the inflatable body 18 as far as the beginning of the section of the air-supply device 12 , around which the shirt collar is positioned. In the inflated state, the enclosure 4 of the inflatable body 18 pushes against the button-strip clamp 14 from behind. As a result, the inflatable body 18 tries to push itself away from the button-strip clamp 14 in the rearward direction. To counteract such deflection of the inflatable body 18 , the side surfaces of the framework 8 are turned somewhat forward. As a result, the normal of these surfaces is inclined in relation to the inflatable-body trunk. Such inclination causes the force of the side chambers 1 to be directed not just perpendicularly outward, but also a little in the forward direction. As a result, despite the pressure exerted by the button-strip clamp 14 , the inflatable body 18 is not deflected rearward.
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A shirt-shaped inflatable body for pressing shirts and on which the shirt is stretched flat includes lateral cavities, which are inflated by an increased pressure, in the sides of the trunk section of the inflatable body. The cavities are supported by a frame located inside the inflatable body and press the trunk section outwards, forming a flat shape. The pressure in the lateral chambers located inside the casing of the inflatable body is increased by the fact that both the casing of the lateral chambers and the casing of the inflatable body are permeable to air and that the lateral chambers are directly supplied with air by a fan, whereas the remaining areas of the inflatable body are only inflated with the air that flows through the casing of the lateral chambers against a flow resistance.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to specimen gathering devices in the medical field to collect biological samples from patients, and in particular to an improved specimen container and handle.
2. Description of the Related Art
Patients are often required to provide samples of urine or stool so that their treating physician can properly diagnose an illness. Also, employees are often required to produce urine samples for drug testing. Although in many situations the patient or employee is allowed to produce the sample in private, the main drawback is that they or a family member must hold the specimen container while the sample is obtained. Subsequently, the hand of the person holding the container often is soiled while obtaining the specimen.
Other specimen gathering devices as well as handles for holding conventional specimen cups have been proposed so that the hand of the person holding the container is farther away from the container. While reducing the problem of hand soiling, these devices have other problems. Some of the previous proposals are so complicated that they are not easy to assemble, while others are too difficult for the elderly to assemble on their own. Other devices appear to be too expensive to manufacture in mass quantities for disposal after a single use or the devices are bulky and difficult to package.
SUMMARY OF THE INVENTION
A device for collecting a specimen from a patient has a container for holding the specimen as it is deposited and a handle having a hoop for holding the container. The container has a downward facing shoulder for engagement by the hoop, the handle being located near the upper portion of the container. The container rests inside of the hoop with the shoulder in contact with the upper edge of the hoop to prevent the container from sliding through the hoop. The hoop is retained in position on the container by at least one protrusion located around the circumference of the container below the shoulder.
The protrusions are large enough so that the circumference around the radially outermost portions of the protrusions has an effective diameter that is larger than the inner diameter of the hoop of the handle. The protrusions force the hoop to deform as it passes over the protrusions to engage the shoulder. The protrusions can be a series of intermittently spaced objects around the circumference of the container, or a continuous ring that surrounds the container. The protrusions can be adapted so that the lower portion of the protrusion is smaller in diameter to allow the hoop to slide over the protrusions more easily.
The protrusions can be located so that they are in contact with the inner surface of the hoop when the hoop engages with the shoulder. In this location, the protrusions form an interference fit with the inside of the hoop and frictionally keep the hoop from sliding down the container. The protrusions can also be located so that they are below the hoop when the hoop engages the shoulder. In this arrangement, the protrusions are a physical barrier to downward movement of the hoop relative to the container.
The handle and all of the containers are easily mass manufactured so the cost associated with each specimen collector is low. The handles are easily attached to the containers so they are capable of being used by children and the elderly. The handles provide a distance between the cup and the hand to prevent soiling the hand of the person holding the specimen collector while the specimen is deposited.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a container and handle of a specimen collecting device constructed in accordance with this invention.
FIG. 2 is an elevational view of one embodiment of a portion of the container shown in FIG. 1 .
FIG. 3 is an elevational view of another embodiment of a portion of the container shown in FIG. 1 .
FIG. 4 is an elevational view of another embodiment of a portion of the container shown in FIG. 1 .
FIG. 5 is an elevational view of another embodiment of a portion of the container shown in FIG. 1 .
FIG. 6 is a cross-sectional view of the container shown in FIG. 5 , taken along the line 6 — 6 of FIG. 5 .
FIG. 7 is an elevational view of another embodiment of a portion of the container shown in FIG. 1 .
FIG. 8 is an elevational view of another embodiment of a portion of the container shown in FIG. 1 .
FIG. 9 is an elevational view of another embodiment of a portion of the container shown in FIG. 1 .
FIG. 10 is an elevational view of another embodiment of a portion of the container shown in FIG. 1 .
FIG. 11 is an elevational view of another embodiment of a portion of the container shown in FIG. 1 .
FIG. 12 is an elevational view of another embodiment of a portion of the container shown in FIG. 1 .
FIG. 13 is an perspective view of the assembly of the specimen collector shown in FIG. 12 , and showing the handle being installed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1 , a container 11 is shown with a handle 13 attached to container 11 . Container 11 is a collection cup for specimen samples. Container 11 is for collecting urine, stool, or other specimens for the diagnosis of a patient by a treating physician and for collecting urine for drug testing. In the preferred embodiment, container 11 is formed of a suitable plastic such as polypropylene. Container 11 is substantially cylindrical, having inclined sides making the lower portion of container 11 smaller in diameter than the upper portion. Container 11 has a bottom side enclosing the lower portion of container 11 . The top side of container 11 is open for receiving a specimen.
Handle 13 is an elongated member with an integrally formed hoop 15 on one end to slide over the outer surface of container 11 from the lower portion towards the upper portion of container 11 . A gripping region 17 is located on the end of handle 13 opposite hoop 15 . Handle 13 is a plastic material strong enough for a person holding gripping region 17 to support container 11 after the specimen is deposited in container 11 . Preferably, handle 13 is formed of polystyrene although other materials are suitable. Handle 13 is fairly rigid. Hoop 15 may be deformed, but does not readily stretch in diameter in the preferred embodiment so as to provide adequate stability.
Threads 19 are located on the outer surface of the upper portion of container 11 for receiving a conventional lid (not shown) having internal threads. Container 11 is closed and sealed to prevent loss of the specimen when threads 19 receive the lid (not shown). Referring to FIG. 2 , a downward facing annular shoulder 21 is located on the outer surface of the upper portion of container 11 for receiving the top surface of hoop 15 (shown in FIG. 1 ). Shoulder 21 is below threads 19 . The outer diameter of shoulder 21 is larger than the inner diameter of hoop 15 (FIG. 1 ), and the top surface of hoop 15 engages shoulder 21 . Shoulder 21 is a physical barrier to hoop 15 ( FIG. 1 ) sliding up the outer surface of container 11 to the threads 19 . Shoulder 21 prevents container 11 from sliding through hoop 15 when someone holding gripping region 17 supports container 11 . An annular engagement zone 23 is defined by the portion of container 11 below shoulder 21 . Engagement zone 23 is surrounded by hoop 15 ( FIG. 1 ) when hoop 15 engages shoulder 21 . Engagement zone 23 has a vertical dimension or thickness that is slightly more than the thickness of hoop 15 (FIG. 1 ). In this embodiment, the outer diameter of engagement zone 23 is slightly less than the inner diameter of hoop 15 (FIG. 1 ).
Referring to FIG. 2 , a set of ribs 25 are located in engagement zone 23 around the circumference of container 11 below shoulder 21 . Ribs 25 are preferably evenly spaced around the circumference of engagement zone 23 . Also, preferably the circumferential space between each rib 25 and another rib 25 is much greater than the circumferential thickness of each rib 25 . The outer surface of each rib 25 is a small segment of a cylinder that defines an effective diameter. Ribs 25 are oriented axially along the axis of container 11 so that ribs 25 extend from shoulder 21 towards the lower portion of container 11 , preferably terminating at the lower edge of engagement zone 23 .
The outer diameter extending around the circumference of the portion of container 11 at the exterior surface of ribs 25 defines an effective diameter that is less than the outer diameter of shoulder 21 and slightly greater than the inner diameter of hoop 15 (FIG. 1 ). In the preferred embodiment, the effective diameter of ribs 25 is substantially the same around the upper and lower portions of ribs 25 . The material of hoop 15 ( FIG. 1 ) is flexible enough for hoop 15 to deform as hoop 15 is pulled upward over ribs 25 . Once installed, the inner surface of hoop 15 ( FIG. 1 ) is in contact with the outer surface of ribs 25 when hoop 15 engages shoulder 21 . Ribs 25 form an interference fit with the inner surface of hoop 15 ( FIG. 1 ) when hoop engages shoulder 21 , the frictional engagement preventing container 11 from rotating inside of hoop 15 . Although hoop 15 does not readily stretch when installed, it does tend to flatten between ribs 25 so as to be able to locate over the larger effective diameter of ribs 25 .
In operation a patient or operator orients handle 13 ( FIG. 1 ) relative to container 11 so hoop 15 ( FIG. 1 ) is surrounding the lower portion of container 11 . The patient moves handle 13 and slides hoop 15 along the inclined sides of container 11 towards the upper portion of container 11 . The patient slides hoop 15 ( FIG. 1 ) substantially perpendicular to the long axis of container 11 over ribs 25 until the upper edge of hoop 15 ( FIG. 1 ) engages shoulder 21 .
After the patient deposits the specimen in container 11 , the patient or a medical technician can disassemble the specimen collecting device. Preferably a lid (not shown) is first installed. To disassemble the device, the patient tilts handle 13 ( FIG. 1 ) to cause hoop 15 ( FIG. 1 ) to disengage from ribs 25 and shoulder 21 . The patient or technician then slides hoop 15 down the inclined sides of container 11 until hoop 15 clears the lower portion and no longer surrounds container 11 .
Referring to FIG. 3 , a second embodiment of container 11 is shown having a set of axially oriented tapered ribs 29 in engagement zone 23 . Like ribs 25 , ribs 29 are spaced around the circumference of container 11 . Ribs 29 also have an effective diameter defined around the circumference of the radially outermost portions of ribs 29 that is less than the outer diameter of shoulder 21 and greater than the inner diameter of hoop 15 (FIG. 1 ).
In the embodiment shown in FIG. 3 , ribs 29 have lower portions with inclined faces 33 angling inward from an axially middle portion of ribs 29 to the axially lowermost portion of ribs 29 . The effective diameter around inclined faces 33 of ribs 29 is substantially the same or slightly less than the inner diameter of hoop 15 (FIG. 1 ). The effective diameter around the portion of ribs 29 above inclined faces 33 is larger than the inner diameter of hoop 15 (FIG. 1 ). The effective diameter around inclined faces 33 allows hoop 15 ( FIG. 1 ) to more slide over the lowermost portions of ribs 29 more easily than in the first embodiment.
Like the first embodiment, hoop 15 ( FIG. 1 ) deforms as hoop 15 engages the portion of ribs 29 above inclined faces 33 because effective diameter is larger than the inner diameter of hoop 15 . The inner surface of hoop 15 ( FIG. 1 ) is in frictional contact with the outer surface of the portion of ribs 29 above inclined faces 33 when hoop 15 engages shoulder 21 . Ribs 29 form an interference fit with the inner surface of hoop 15 ( FIG. 1 ) when hoop 15 engages shoulder 21 , preventing container 11 from sliding too easily from hoop 15 . Once installed, the lower edge of hoop 15 ( FIG. 1 ) is above inclined faces 33 .
In operation, the patient attaches handle 13 ( FIG. 1 ) relative to container 11 so hoop 15 ( FIG. 1 ) is surrounding the lower portion of container 11 . The patient moves handle 13 ( FIG. 1 ) and slides hoop 15 ( FIG. 1 ) along the inclined sides of container 11 towards the upper portion of container 11 . The patient slides hoop 15 ( FIG. 1 ) substantially perpendicular to the long axis of container 11 , first over inclined faces 33 then over ribs 29 until the lower edge of hoop 15 ( FIG. 1 ) is above inclined faces 33 . Inclined faces 33 allow the inner surface of hoop 15 ( FIG. 1 ) to slide over the lower portions of ribs 29 more easily than the inner surface can slide over the lower portions of ribs 25 in the embodiment shown in FIG. 2 .
In the embodiment shown in FIG. 4 , a set of protuberances or bosses 35 are located around the outer surface of container 11 in engagement zone 23 below shoulder 21 . Bosses 35 are substantially hemispherical in shape and define an effective diameter around the radially outermost portions of bosses 35 . Bosses 35 are evenly spaced apart from each other. The spaces between bosses 35 are much greater than the diameter of each bosses 35 . The effective diameter around the radially outermost portions of bosses 35 is larger than the inner diameter of hoop 15 ( FIG. 1 ) causing hoop 15 to deform as hoop 15 engages bosses 35 . The inner surface of hoop 15 ( FIG. 1 ) is in contact with the radially outermost surface of bosses 35 when hoop 15 engages shoulder 21 . Bosses 35 form an interference fit with the inner surface of hoop 15 ( FIG. 1 ) when hoop engages shoulder 21 , preventing container 11 from sliding out of hoop 15 .
In operation, the patient attaches handle 13 to container 11 in the same manner as the embodiment shown in FIG. 3 . The lower portions of hemispherically shaped bosses 35 allow the inner surface of hoop 15 ( FIG. 1 ) to slide over the lower portions of bosses 35 more easily than the inner surface of hoop 15 can slide over the lower portions of ribs 25 in the embodiment shown in FIG. 2 . Instead of single bosses 35 , two or more bosses could be located at each location, one above the other and perpendicular to the long axis of container 11 .
In the embodiment shown in FIGS. 5 and 6 , engagement zone 23 comprises a polygonal engagement zone 43 that extends around the outer surface of container 11 below shoulder 21 . As shown in FIG. 6 , the cross-section of engagement zone 43 is substantially an octagon in shape. A series of points or comers 45 are defined by the intersections of each side of polygonally shaped engagement zone 43 . The effective diameter is defined for the circumference extending around points 45 of engagement zone 43 . The effective diameter is larger than the diameter of container 11 below engagement zone 43 and smaller than the diameter of shoulder 21 . Engagement zone 43 can be other polygonal shapes such as hexagons, heptagons, nonagons, decagons, or the like so long as the effective diameter remains larger than the diameter of the portion of container 11 below engagement zone 43 , and smaller than the diameter of shoulder 21 .
The effective diameter around points 45 is larger than the inner diameter of hoop 15 (FIG. 1 ). Hoop 15 deforms as hoop 15 engages polygonal engagement zone 43 . The inner surface of hoop 15 ( FIG. 1 ) is in frictional contact with points 45 when hoop 15 engages shoulder 21 . Points 45 of polygonal engagement zone 43 form an interference fit with the inner surface of hoop 15 (FIG. 1 ), preventing container 11 from slipping. In operation, the patient attaches handle 13 to container 11 for this embodiment in the same manner as described for the embodiment in FIG. 2 .
Referring to FIG. 7 , another embodiment is shown having a set of ribs 49 located in engagement zone 23 . Ribs 49 are similar to ribs 25 ( FIG. 2 ) but are semi-cylindrical. Ribs 49 are evenly spaced apart and define an effective diameter of the circumference around the outermost portions of ribs 49 .
A rounded surface 53 is preferably located on the axially lowermost portion of ribs 49 . Rounded surfaces 53 have an effective diameter less than the effective diameter for the upper portion of ribs 49 . The effective diameter of rounded surfaces 53 is substantially the same or less than the inner diameter of hoop 15 (FIG. 1 ). In operation, the patient attaches handle 13 ( FIG. 1 ) to container 11 in the same manner as described for the embodiment in FIG. 3 . Rounded surfaces 53 allow the inner surface of hoop 15 ( FIG. 1 ) to slide over ribs 49 more easily. Once installed, the lower side of hoop 15 ( FIG. 1 ) will be above rounded surfaces 53 .
Referring to FIG. 8 , a polygonal engagement zone 55 is located in engagement zone 23 . Polygonal engagement zone 55 is similar to engagement zone 43 (FIG. 6 ), having a set of points 57 at the interfaces of each of the sides of polygonal engagement zone 55 . Points 57 define an effective diameter of the circumference around points 57 . Engagement zone 55 differs from engagement zone 43 in that the lower portion has a rounded surface 61 .
Rounded surface 61 has an effective diameter less than the effective diameter for the upper portion of points 57 . Rounded surface 61 has effective diameter substantially the same or less than the inner diameter of hoop 15 ( FIG. 1 ) thereby allowing hoop 15 ( FIG. 1 ) to slide over the lower portion of points 57 more easily. In operation, the patient attaches handle 13 ( FIG. 1 ) to container 11 for this embodiment in the same manner as described for the embodiment of FIG. 3 . Once installed, the lower surface of hoop 15 ( FIG. 1 ) is above rounded surface 61 .
Referring to FIGS. 9-11 , different shaped protrusions are spaced around the circumference of container 11 below engagement zone 23 . In the embodiment shown in FIG. 9 , the protrusions are substantially half-cylinders 65 evenly spaced around the circumference of container 11 at the lower edge of engagement zone 23 . The long axes of half-cylinders 65 are substantially parallel to engagement zone 23 and shoulder 21 . Half-cylinders 65 define an effective diameter around the outermost portions of half-cylinders 65 that is greater than the inner diameter of hoop 15 (FIG. 1 ).
In the embodiment shown in FIG. 10 , a series of protruding hemispherical bosses 69 are evenly spaced around the circumference of container 11 at the lower edge of engagement zone 23 . Bosses 69 define an effective diameter around the outermost portions of bosses 69 that is greater than the inner diameter of hoop 15 (FIG. 1 ).
In the embodiment shown in FIG. 11 , a barrier ring 73 extends continuously around the circumference of container 11 at the lower edge of engagement zone 23 . The outer diameter of ring 73 is greater than the inner diameter of hoop 15 (FIG. 1 ).
The effective diameters for protrusions 65 , 69 , and 73 are larger than the outer diameter of engagement zone 23 and the inner diameter of hoop 15 ( FIG. 1 ) for their respective embodiments. In the embodiments shown in FIGS. 9-11 , a portion of hoop 15 ( FIG. 1 ) slides over half-cylinders 65 , bosses 69 , or ring 73 , then handle 13 ( FIG. 1 ) is rotated upward. Hoop 15 ( FIG. 1 ) deforms as it slides over protrusions 65 , 69 , and 73 . Once installed hoop 15 ( FIG. 1 ) is located over engagement zone 23 below shoulder 21 and above protrusions 65 , 69 , or 73 . The inner diameter of hoop 15 ( FIG. 1 ) is greater than the outer diameter of engagement zone 23 .
Referring to FIG. 12 , the sidewall portion of container 11 at the lower edge of engagement zone 23 forms a physical barrier to downward movement of hoop 15 (FIG. 1 ). The outer diameter of the sidewall portion and engagement zone 23 define a lip 77 at the lower edge of engagement zone 23 . The diameter of lip 77 is larger than the diameter of engagement zone 23 and larger than the inner diameter of hoop 15 (FIG. 1 ). Lip 77 , like protrusions 65 , 69 , and 73 (FIG. 9 - 11 ), prevents hoop 15 ( FIG. 1 ) from sliding downward relative to container 11 .
Referring to FIG. 13 , to install hoop 15 , the patient moves handle 13 along the exterior surface of container 11 as shown by movement A. The patient then places a portion of hoop 15 above lip 77 with handle 13 inclined as shown in FIG. 13 . The user then rotates handle 13 upward as represented with movement B of FIG. 13 . Hoop 15 is removed from engagement zone 23 by rotating handle 13 in the opposite direction of movement B. Lip 77 holds hoop 15 in engagement with shoulder 21 , which makes collection of specimen an easier task for the patient.
The containers and handles in the embodiments described above are easy to manufacture in mass quantities. The handles do not need to vary depending upon the different embodiments that are chosen. The handle is easily positioned and removed from all of the different embodiments of the containers described above, which allows children or the elderly to assemble the collection device by themselves and in privacy. Thus container and cup reduce the chances for soiling one's hands.
Further, it will also be apparent to those skilled in the art that modifications, changes and substitutions may be made to the invention in the foregoing disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in the manner consisting with the spirit and scope of the invention herein.
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A device for collecting biological specimens having a container and a detachable handle. The handle allows a person to position the container so that contact between the person and sample is minimized or avoided. The handle includes a hoop into which the container slides from the container's lower end. The container is configured with projections on its outer surface that frictionally engage the hoop. Alternatively, the container can be configured with projections, a ring, or a lip over which the hoop is obliquely traversed to prevent the hoop from sliding downward on the outer surface of the container. The handle is constructed of a flexible material so that it may deform as needed when engaging the outer surface of the container.
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FIELD AND BACKGROUND OF THE INVENTION
[0001] The present invention relates to an ultrasound tracking device, system and method and, more particularly, but not exclusively to a device that uses three dimensional ultrasound imaging techniques and invasive tools.
[0002] Three dimensional ultrasound scanning is known from a number of patent applications including EP 0 920 642, 3D Ultrasound Recording Device, assigned to Synthes A G of Chur, Switzerland. An effective system for displaying 3D ultrasound imaging data is disclosed in U.S. Pat. No. 5,682,895 to Ishiguro.
[0003] Three-dimensional ultrasound has the advantage of acquiring a data set of images that can be accumulated to volume from a single ultrasonic window. The two dimensional slice data from the scanner or probe is used as input data for the three dimensional reconstructions.
[0004] Basics and Principles:
[0005] Three-dimensional imaging is based on two-dimensional imaging. Two dimensional imaging involves acquiring planar sweeps, and the three dimensional image is built up from a series of planes making up a volume. The data can be acquired by parallel, rolling or sweep type probe movements. The volume may then be displayed in various ways. In fact, three dimensional images can be produced using a number of different methods, the most complex of which comprises generating three dimensional images based on the acquisition of a large number of consecutive 2 dimensional images through the movement of the transducer.
[0006] The sweep acquisition can be done free-hand with or without orientation sensors or using a specialized transducer which sweeps a volume mechanically as a series of planes and allows the processing of these volumes in a standard manner. The volume is then digitally stored and can be displayed either as a multi-planar image showing three orthogonal planes or as a surface rendered image. The three perpendicular planes display the X, Y and Z axes with the understanding that the Z plane is one that can not be acquired directly.
[0007] An advantage of three-dimensional imaging is that it enables reorienting of the display plane after the volume has been acquired, allowing the other two planes to be viewed. In fact, further than that, it is possible to view a standard two-dimensional cross sectional image in any plane within the volume, and gives free access to viewing angles that are in fact inaccessible. The user is thus enabled to effectively rescan a patient by reviewing the saved volume in any two-dimensional plane, even if different from the original scan plane. Such an effective rescan is particularly useful, for example in fetal imaging where frequently a fetus being imaged is not in an ideal position. The acquired volume can be manipulated to display the image in a non-scanning reconstructed plane. The image of a fetal profile, for example, is necessary to image the chin, and may not be obtainable on a fetus that is not positioned properly. The volume of the fetal face can be displayed in any desired orientation, including a sagittal view, to optimize the fetal profile or any other area if interest. Returning to the question of representing the gathered volume data, the spatial orientation of sonogram sweep data is monitored throughout the process of acquisition and the data are then stored in the computer memory as a volume set. The relative position and orientation of the 2 dimensional images can be established using mechanical, electromagnetic or acoustic techniques. There are then three ways to evaluate the volume dataset:
[0008] 1. Section reconstruction
[0009] 2. Surface rendering.
[0010] 3. Volume rendering.
[0011] By using three dimensional ultrasound there is the possibility to reconstruct and display any arbitrary chosen 2 Dimension section plane within the scanned area.
[0012] The volume scan may automatically be performed by a tilt movement added on top of the standard 2D scan mechanism.
[0013] Applications of 3D
[0014] There are many useful applications for three-dimensional volume acquisition of two-dimensional ultrasound. The first includes networking and the ability to send packets of information from one site to another. The information obtained with three-dimensional volume acquisition is far superior to simply a video or cine-loop of two dimensional information. Several studies have demonstrated the benefit of using three-dimensional volume sets to send to a remote location via electronic networks to a specialist, who may then review the data and render an interpretation. The specialist can interactively reorient the volume even if the imaging was not done in an ideal plane or if the fetus was not in a desired position. This enables sites distant from a central location to optimize their backup capabilities using remote “expert” consultation.
[0015] There is a definitely a learning curve to the ability to obtain a good volume set and the training of the sonographer or the physician obtaining the volumes as well as those reading it must be different than the training in standard 2D imaging. Training must include standard acquisitions of volumes that will display with a minimum of artifact. Sonographers must recognize inadequate volumes that cannot be used due to motion or other artifacts. The training of physicians reviewing the volumes must also include learning how to evaluate anatomy in orientations different from the original acquisition plane. A standardized protocol must also be in place so that the volumes are not viewed haphazardly but in a standard fashion and in multiple planes.
[0016] Further research evaluates the feasibility of performing a virtual patient examination using three-dimensional ultrasound acquired in one location and sent to remote locations to be read. They demonstrate that overall, 3D ultrasound could be used with diagnostic quality results comparable to standard two-dimensional ultrasound, although the reconstructed 3D image quality itself is generally lower than the directly acquired two-dimensional image. There are also differences among reviewers interpretations thus emphasizing the need for a standardization of acquisition and reviewing protocols for users. Three-dimensional virtual examination techniques are regarded as being particularly well suited for echocardiography, where volumes can be sent via the Internet to a tertiary fetal cardiology center to reevaluate a cardiac data set. Studies show that a three-dimensional virtual examination of the fetal heart is possible although there are still limitations that need to be worked out. Certainly the main cardiac connections can be viewed and reconstructed in different ways. This may be helpful to patients being scanned in remote locations where questions about cardiac anatomy may arise.
[0017] Ultrasound guided prostate seed brachytherapy is a new, non-invasive, outpatient procedure that uses 3D ultrasound imaging to assist with correct positioning of implants in order to treat patients in the early stage of prostate cancer.
[0018] The prostate brachytherapy procedure involves implanting tiny radioactive rice-sized pellets directly into the prostate, where they can irradiate the prostate from the inside. Physicians use ultrasound based three-dimensional imaging techniques to place seeds at exact spots and intervals so actual radiation only penetrates a short distance, thereby minimizing radiation to adjacent organs. The seeds emit radiation from inside the prostate for about nine months and then become inert, with no need for removal. Brachytherapy is effective for cancer that has not spread beyond the boundaries of the prostate gland.
[0019] The procedure is a three-step procedure; acquisition of two-dimensional images, processing and finally visualization or display. The data starts out as slices (images) taken at regular intervals using echo-endoscope, ultra-thin probes or laparoscopic probes using a computer controlled acquisition device which uses an algorithmic approach to obtain a three dimensional representation of the internal organ.
[0020] Image guided neurosurgery (IGNS) is a field that currently exists. However, it is generally felt that current techniques lack accuracy.
[0021] There are many aspects of an image-guided surgery system that can potentially introduce errors into the system. Since one of the objectives of IGNS is to achieve an accuracy and precision of better than 1 mm (particularly for functional stimulation, ablation and tissue implants), there is currently a great deal of effort being expended to identify sources of error and to propose means of eliminating them.
[0022] One currently used way of dealing with inaccuracy is to gather as accurate information as possible from the patient and to combine the data with that already gathered from an atlas of previously obtained data. Even the highest quality MR images fail to demonstrate some of the fine detail and structures necessary for the surgeon to perform certain procedures, for example, thalamotomy and pallidotomy. On the other hand, detailed atlases of these structures exist, and they may be merged, using a non-linear warping procedure, with the patient's MR images to provide additional guides and landmarks during surgery. These atlases may be complemented with a probabilistic electro-physiological atlas using data acquired at surgery.
[0023] Image-Guided Neurosurgery—Background
[0024] The central hypothesis of IGNS is that if the neurosurgeon can be provided with rich, image-based information describing the underlying anatomy, function, and vascularity, along with tools that allow him to interpret and use this information effectively, then surgical procedures can be made less invasive, and patient morbidity, hospitalization time and cost will be reduced.
[0025] These image-guided tools provide a virtual, non-invasive “window” into the body, allowing the surgeon visual access to anatomical details and physiological function that are not available using other means. Over the past 15 years, the work in this laboratory has evolved in parallel with both the explosion in computer power and capacity, and the development and refinement of 3-D diagnostic imaging modalities. It has taken maximum advantage of the increasing power and accuracy offered by technology, while at the same time ensuring that the tools are surgeon-friendly and cost effective.
[0026] The ultimate objective of minimally invasive neurosurgery is to remove completely the targeted lesion by damaging the smallest possible volume of brain tissue, causing the least trauma to the patient, to achieve the desired therapeutic result. To achieve this objective, the goal of an ideal IGNS system is to report the position of an intra-operative guidance device within the brain with perfect accuracy. This would require that the brain images presented to the surgeon on a video monitor always reflect the actual geometrical state of the brain. This goal is partly achieved by registering the image data to the patient by identifying common structures in the patient and the image. However, in reality, even if the patient-image registration problem has been addressed perfectly, most IGNS systems use preoperative image information and their accuracy is affected by many factors. Most can be attributed to failures of basic assumptions under the following three categories:
[0027] Image Assumptions: that the images used as guidance for surgery contain all of the relevant anatomical and functional information required for surgical guidance;
[0028] Instrumentation Assumptions: that the images are geometrically accurate, the tracking device is free of positioning error, the registration between the patient and image is correct, and the images are free from spatial distortion; and,
[0029] Brain Tissue Assumptions: that the equipment and volume of surgical interest form a completely rigid system, implying that the structures of interest within the brain remain in the same position during surgery with respect to the external fiducial points used for patient-image registration The following passage, describes the use of 3-D ultrasound in neurosurgery. “Recently, it was reported that current generation ultrasound imagers are capable of visualizing the intra-cranial vasculature, which can be reconstructed as 3-D volumes, and we have demonstrated the clinical applicability of combining intra-operative ultrasound images with pre-operative MRI. The next step is to use the target images to update the geometry of the pre-operative images. The goal may be achieved by developing strategies that match similar structures (vessels and tissue boundaries) that are detected in both ultrasound and MR images. This will allow inference of the displacement of a field of “tag-points” between the ultrasound and MR images. This displacement map will then be used to calculate the deformation necessary to match the pre-operative MRI to the ultrasound image. The original 3-D MRI data will thus be updated based on the changing morphology detected by ultrasound during surgery. Such fusion of MRI and 3-D ultrasound may result in a near real-time intra-operative imaging system that maintains the attributes of the pre-operative MRI. It will present substantial advantages over specialized intra-operative MR imaging systems, both in image resolution and cost.”
[0030] A paper by Aaron Fenster and Donal B. Downey of Imaging Research Laboratories, The J. P. Robarts Research Institute Ontario, Canada, discusses three-dimensional ultrasound imaging. According to the paper, ultrasonography, a widely used imaging modality for the diagnosis and staging of many diseases, is an important cost-effective technique, however, technical improvements are necessary to realize its full potential. 2D viewing of 3D anatomy, using conventional ultrasonography, limits our ability to quantify and visualize most diseases, causing, in part, the reported variability in diagnosis and ultrasound guided therapy and surgery. This occurs because conventional ultrasound images are 2D, yet the anatomy is 3D; hence, the diagnostician must integrate multiple images in his mind. This practice is inefficient, and may lead to operator variability and incorrect diagnoses. In addition, the 2D ultrasound image represents a single thin plane at some arbitrary angle in the body. It is difficult to localize and reproduce the image plane subsequently, making conventional ultrasonography unsatisfactory for follow-up studies and for monitoring therapy.
[0031] The authors have focused on overcoming these deficiencies by developing 3D ultrasound imaging techniques that can acquire B mode, color Doppler and power Doppler images. An inexpensive desktop computer is used to reconstruct the information in 3D, and then is also used for interactive viewing of the 3D images. They use 3D ultrasound images for the diagnosis of prostate cancer, carotid disease, breast cancer and liver disease and for applications in obstetrics and gynecology. In addition, they use 3D ultrasonography for image-guided minimally invasive therapeutic applications of the prostate such as cryotherapy and brachytherapy. Volume Measurements Another important clinical application of 3D is volume measurements calculations based on 3D volume acquisition. Only as a result of acquiring a complete volume is it feasible to make an accurate volume estimation for tissues or tissue regions under study. Real-Time 3D or 4D Researchers have attempted to use real-time 3D (otherwise known as 4D) in the assessment of fetal behavior during pregnancy. Although the number of frames per second is still less than required for a smooth real time image, there is enough information using continuous three-dimensional ultrasonographic images to display fetal activity. It is unclear however how much more information is available using 3D than 2D real-time, since fetal movement is readily visible in 2D, which have been used to study fetal movement successfully for many years. It may however be possible to image more of the fetal body at once using real-time 3D surface rendering than using the single slice standard 2D imaging. Multi-planar displays in real-time (3D) may also be advantageous to visualize movement in a non-scanning (or Z) plane. It remains to be seen whether real-time 3D (or 4D) sonography will play a role in the evaluation of fetal well-being during gestation.
[0032] Generally it requires a large amount of scanning and image processing to keep a standard one-dimensional ultrasound image updated for real time applications.
[0033] Considerably more processing is needed to keep a three dimensional ultrasound image updated for real time applications.
[0034] Uterine Procedures:
[0035] Moving now from fields where imaging is widely used, as of today intrauterine and cervical procedures are generally performed by an archaic “blind” technique, which is to say either the surgeon does not use imaging at all, or if he does use imaging then the tool he is using and the region he is operating on does not appear in the images or only appears with great effort. To name a few common procedures: Curettage or evacuation of the uterine cavity for diagnostic and/or therapeutic purpose including termination of pregnancy (TOP); Removal of an endometrial polyp or submucous myoma; Insertion or extraction of an intra-uterine contraceptive device; sampling of the endometrium and/or the endocervix for diagnostic purposes; embryo transfer during in-vitro fertilization (IVF); and tubal diagnostic for treatment procedures.
[0036] Due to lack of ability to image the tool, the above procedures are generally carried out blindly, relying on the surgeon's experience and “feel” through manual manipulation of the instruments over the uterus walls.
[0037] When the position or size of the uterus is incorrectly diagnosed or recognized by the surgeon, which is often the case with inexperienced physicians, uterine perforation may occur with remarkable ease. The chances of perforation are higher in the presence of cervical stances or uterine malignancy (endometrial or sarcoma). The dangers in such uterine perforation include bleeding and trauma to the abdominal viscera as well as damage to internal organs. Thus, hospitalization and exploration of the abdominal cavity by laparoscopy or laparotomy is often needed due to such accidental uterine perforation. Other possible unfortunate outcomes of such blind operation procedures include, for example, failure to completely remove uterine tissues such as placental or fetal tissues during termination of pregnancy, resulting in re-hospitalization (expensive) and the need for a second curettage under general anesthesia (high risk).
[0038] Currently the use of real-time monitoring and guiding of surgical procedures is very limited and usually performed only during complicated procedures (in many cases complications from unguided procedures). In such cases trans-abdominal probes are usually used but they have relatively limited resolution, they require keeping the patient's urinary bladder full during the operation, and they require additional operating staff.
[0039] Image-Guided Gynecologic Surgery—Background
[0040] There is a widely recognized need for, and it would be highly advantageous to have, an apparatus and method for real-time endovaginal sonographic guidance and monitoring of intra-uterine and cervical surgical and non-surgical procedures.
[0041] Such apparatus may enable the surgeon to perform such procedures safely, conveniently and efficiently. In particular, it would be advantageous because of substantially shortening the duration of the surgical procedures currently carried out under general anesthesia, and it would reduce the rate of complications associated with such procedures. Only ten years ago the amniocentesis procedure for pregnant women was performed without ultrasound or any other guidance means. The procedure was performed blindly, with the physicians feeling the position of and collecting the sample of the fluid whilst trying to avoid approaching the fetus. Today, no physician would attempt collection of amniotic fluid without the guidance of a real-time ultrasound image displaying the fetus and the applied needle, and any attempt at such a procedure without ultrasound guidance would be regarded as malpractice.
[0042] Abnormal uterine bleeding is a common reason for gynecological visits by women. Although many of these cases have a benign etiology, the possibility of malignancy must be ruled out. About 7% of postmenopausal women not receiving hormone replacement therapy (HRT), who present with uterine bleeding have a malignancy. Thus, postmenopausal bleeding is considered endometrial cancer until proven otherwise.
[0043] Patients who receive HRT for six months, and then present uterine bleeding, are generally recommended for undergo endometrial sampling.
[0044] Peri-menopausal women with abnormal bleeding are at increased risk of endometrial cancer secondary to their age and anovulatory cycles. Thus, all women with abnormal uterine bleeding in the peri-menopausal period require endometrial sampling.
[0045] Indications for endometrial biopsy in pre-menopausal women with abnormal bleeding are not as straightforward. Beyond adolescence, endometrial cancer should be considered in the differential diagnosis of abnormal uterine bleeding since up to 10% of women with endometrial carcinoma are diagnosed before the age of 45.
[0046] In women under the age of 40 with no risk factors, the chance of endometrial cancer is minimal. The most important risk factor in this group of women is irregular menstrual cycles, which is associated with a 14% chance of an abnormal endometrial biopsy, including benign and malignant lesions. Thus, an endometrial biopsy should be considered in almost all women with irregular cycles.
[0047] Other sub-groups who can be recommended to undergo endometrial sampling with biopsy include patients treated with Tamoxifen, and who then experience abnormal uterine bleeding. In postmenopausal women, the presence of any endometrial cells on a Pap smear is indicative of a need for endometrial sampling. In other women, the presence of atypical endometrial cells should warrant an endometrial biopsy. Patients with malignant endometrial cells on a Pap smear are at significant risk of endometrial cancer, often with high-grade malignancy.
[0048] Detecting the cause of abnormal uterine bleeding requires endometrial tissue sampling, which can be performed as an office procedure.
[0049] Previously, the gold standard for sampling the endometrium was dilatation and curettage (D&C) under general anesthesia. For full evaluation of bleeding, endocervical curettage should also be done to localize the source of bleeding. If no cause of bleeding can be found or if the tissue obtained is inadequate for diagnosis, D&C must be performed. It is now recognized that D&C is actually a “blind” sampling technique, which often samples less than half of the endometrium.
[0050] Another technique uses the endometrial Pipelle or Z-Sampler and has further simplified endometrial sampling. The Pipelle is a flexible polypropylene suction cannulas, generally having an outer diameter of 3.1 mm and its use is almost painless in most situations, with particular ease of use in the postmenopausal woman.
[0051] Although false negatives may occur in focal malignancy of the endometrium, it was found that the sensitivity and specificity of the Pipelle in endometrial tissue samplings compared with fractional curettage were 87.5 and 100 per cent, respectively. Guido et al also studied Pipelle biopsies in patients with known carcinoma undergoing hysterectomy. It was found that a Pipelle biopsy provided adequate tissue for analysis in 63 out of 65 patients (97%). Malignancy however, was detected in only 54 patients (83%). It was noted that tumors localized in a polyp or a small area of endometrium may go undetected. Guido et al concluded that the “Pipelle is excellent for detecting global processes in the endometrium.”
[0052] In yet another technique, Vabra, an aspirator is used to obtain tissue for histological examination. A narrow (3-4 mm) suction curette with a vacuum pump is used to perform curettage of an adequate endometrial sample, which allows histological diagnosis of hyperplasia and endometrial carcinoma. Rodriquez et al (26) studied hysterectomy specimens and showed that the percentage of endometrial surface sampled by the Pipelle biopsy was 4% versus 41% for the Vabra aspirator.
[0053] The accuracy of endometrial biopsy in detecting endometrial disease, especially cancer, is highly acceptable. In studies comparing endometrial biopsies to hysterectomy specimens, endometrial biopsy had sensitivities ranging from 83 to 96% for detecting endometrial cancer. Currently, endometrial biopsy has replaced D&C as the diagnostic test of choice for evaluation of abnormal bleeding as both tests have shown to be similarly accurate.
[0054] The above procedures comprise techniques for sampling endometrial tissue, which involve a certain risk of complication, attributed to the fact that they are performed without continuous visualization of the organs and operating tools during the procedure.
[0055] The use of endovaginal ultrasound in women at high risk of endometrial neoplasia is gaining popularity. Currently available evidence indicates that endovaginal ultrasonography is an acceptable alternative to endometrial biopsy as the initial step in evaluating abnormal vaginal bleeding in postmenopausal women from the standpoints of accuracy, patient acceptability, and cost. This indirect method of visualizing the uterine cavity and measuring endometrial thickness has a sensitivity of 96% for detection of endometrial cancer and 92% for detection of any endometrial disease (cancer, polyps, or atypical hyperplasia) in postmenopausal bleeding. The sensitivity of transvaginal ultrasound compares favorably with that of office endometrial biopsy; sensitivity estimates for biopsy published in the literature ranges from 85% to 95% (ref).
[0056] Nondirected office biopsy carried out alone without imaging suffers from a potential to miss the diagnosis of focal lesions such as polyps, submucous myomas, and focal hyperplasia in up to 18% of the patients.
[0057] Diagnostic hysteroscopy and sonohysterography are equally effective in assessing the endometrium. Krampl et al confirm the findings of others showing that ultrasound, hysterosonography, and diagnostic hysteroscopy are not sufficient to identify endometrial pathology. None of these diagnostic tests can in fact replace the use of biopsies for the diagnosis of endometrial abnormalities. Hysteroscopy and hysterosonography are useful in the diagnosis of focal intrauterine pathology, but in order to improve diagnostic accuracy they need to be combined with endometrial sampling. The problems outlined above indicate the need to have some form of coordination between imaging or like information gathering and tool operation. Such co-ordination is presently known from a system marketed as Safe-T-Choice™, which provides a combination solution for uterine sonography and intrauterine operative procedures via a technology which employs a transvaginal transducer that is connected to the instrument holding the cervix (tenaculum) via an adapter. The solution provides real time sonographic guidance for continuous viewing of the organs and tools during procedures performed within the uterine cavity.
[0058] The use of such a transducer can improve the outcome of intrauterine procedures, such as endometrial sampling, while exposing the patients to lesser risks. However, due to the planar nature of ultrasonic scanning, it requires effort on the part of the user to keep the necessary features in view.
[0059] The following references provide further background for this section and are hereby incorporated herein by reference.
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[0084] Weber A M, Belinson J L, Bradley L D, Piedmonte M R. Vaginal ultrasonography versus endometrial biopsy in women with postmenopausal bleeding. Am J Obstet Gynecol. 1997; 177:924-929.
[0085] Steven R Goldstein, , Ilana Zeltser, B S, Camille K. Horan, R D M S, Jon R Snyder, , and Lisa B Schwartz, Ultrasonography-based triage for perimenopausal patients with abnormal uterine bleeding Am J Obstet Gynecol 1997; 177 102-8.
[0086] Rodriguez M H, Platt L D, Medearis A L, Lacarra M., Lobo R A. The use of transvaginal sonography for evaluation of postmenopausal size and morphology. Am J Obstet Gynecol 1998; 159:810-4.
[0087] Guido R S, Kanbour A, Ruhn M, Christopherson W A Pipelle endometrial sampling sensitivity in the detection of endometrial cancer. J Reprod Med 1995;40:553-5.
[0088] Annually some 100,000 millions of surgical procedures of the types discussed above are performed. The complication rate is between 3-6% for termination of pregnancy, and there is an associated inaccuracy rate of 10-20% for sampling specific targets. Most of these complications and inaccuracies occur in blind type procedures. Tracking systems for 3D ultrasound imaging are known, for example from International Patent Application WO 01/06924 to Bova et al. The application discloses a 3D ultrasound probe combined with a tracking device and an arrangement of probe position markers. The markers are tracked using infrared cameras and tracking data from the markers is used to provide a frame of reference to the ultrasound data. However, the frame of reference is absolute and fixed. There is no way of taking into account body movements, particularly breathing, pulse-related movements and other involuntary movements that may occur during surgery. There is no indication of how to relate the frame of reference to points of interest or indeed any way to recognize points of interest. Indeed scanning is limited to flat planes and if a surgical tool is being used, it difficult to ensure that the tool being used features in any of the planes being scanned.
[0089] U.S. Pat. No. 6,338,716 to Hossack et al. describes the use of an ultrasonic transducer probe with a position and orientation sensor. It too suffers from the above limitations.
[0090] There is thus a widely recognized need for, and it would be highly advantageous to have a medical imaging system devoid of the above limitations.
SUMMARY OF THE INVENTION
[0091] According to one aspect of the present invention there is provided apparatus for precision location of a tool within an obscured region, the apparatus comprising:
[0092] a planar scanning unit for scanning planes within the obscured region using an imaging scan, and
[0093] a locator, associated with the tool for determining a location of the tool, and for selecting a plane including the tool location. In a preferred embodiment the locator is operatively associated with the scanner to automatically direct the scanner to the selected plane. However as an alternative the scanner may be handheld. The locator may simply issue a signal, telling the holder of the scanner whether he is scanning the correct plane.
[0094] Preferably, the planar scanning unit is a three-dimensional planar scanning unit configured to build a three-dimensional image by combining scans from a plurality of scan planes, and wherein the selecting comprises selecting planes in different orientations that include the tool location.
[0095] Alternatively, the planar scanning unit is a three-dimensional planar scanning unit configured to build a three-dimensional image by combining scans from a plurality of scan planes, and selecting comprises selecting from the plurality those planes including the tool location.
[0096] Preferably, the locator is user interactive to allow a user to define a feature within a scan, thereby to obtain co-ordinates of the feature to control the scanning unit to scan the feature.
[0097] Preferably, the locator is an image processor, associated with the scanning unit, and configured to process results of the scan therefrom to recognize the tool within the scan, thereby to determine the location.
[0098] Preferably, the image processor is further operable to recognize and follow predetermined tissue features shown in the scan.
[0099] Preferably, the image processor is user interactive to allow a user to define a feature within a scan for following by the image processor, thereby to control the scanning unit to scan the feature.
[0100] Preferably, the tool comprises a fluid route for introducing a fluid into the tool.
[0101] Preferably, the fluid route comprises an inlet, a reservoir region located about an operating end of the tool and an outlet.
[0102] Preferably, the fluid route is filled with bubbled fluid.
[0103] Additionally or alternatively, the fluid route is filled with a contrast agent.
[0104] In one preferred embodiment, the tool is coated with a substance selected to provide contrast in the scan.
[0105] Preferably, the substance is a contrast agent.
[0106] Additionally or alternatively, the substance is an ultrasound reflection agent.
[0107] Preferably, a tip of the tool is at least coated with a substance selected to provide contrast in the scan, thereby to provide precise location of the tip. Preferably, the substance is a contrast agent. Alternatively, the substance is an ultrasound reflection agent.
[0108] In another embodiment, the tool comprises an active ultrasound generator.
[0109] The planar scanning unit may be an ultrasonic scanning unit.
[0110] The ultrasonic scanning unit may be a 3-dimensional ultrasonic scanning unit configured for planar scanning over a plurality of scan planes and the locator may be configured to direct the 3-dimensional ultrasonic scanning unit so as to include the tool location within regions to be scanned of at least two of the scan planes.
[0111] The surgical tool may itself comprise a beacon, and the locator may comprise a corresponding sensor configured to locate the tool by sensing the beacon.
[0112] The beacon may comprise an electromagnetic wave generator.
[0113] The electromagnetic wave generator may be for example an RF generator, a Pico wave generator, a microwave generator, an infra-red wave generator, a light generator, or an x-ray generator.
[0114] The beacon may comprise an ultrasound generator, or even a shockwave generator.
[0115] In a preferred embodiment, the beacon is arranged with at least one other beacon to provide a multi-transmitter remote positioning system and the sensor comprises a receiver for contrasting signals from the remote positioning system to determine co-ordinates relative thereto.
[0116] Preferably, at least one of the beacons comprises an electromagnetic wave generator.
[0117] The electromagnetic wave generator may be for example any of an RF generator, a Pico wave generator, a microwave generator, an infra-red wave generator, a light generator, and an x-ray generator.
[0118] At least one of the beacons may comprise an ultrasound generator. Additionally or alternatively, at least one of the beacons comprises a shockwave generator.
[0119] In another preferred embodiment, the locator comprises:
[0120] a multi-transmitter remote positioning system, and
[0121] a receiver for contrasting signals from the remote positioning system to determine coordinates relative thereto.
[0122] Preferably, the receiver is located on the tool. Alternatively, at least one transmitter of the multi-transmitter remote positioning system is located on the tool.
[0123] The multi-transmitter remote positioning system may comprise at least one electromagnetic wave generator.
[0124] As in the previous embodiment, the electromagnetic wave generator may for example comprise an RF generator, a Pico wave generator, a microwave generator, an infra-red wave generator, a light generator, or an x-ray generator.
[0125] The multi-transmitter remote positioning system may comprise at least one ultrasound generator.
[0126] Preferably, the multi-transmitter remote positioning system comprises a shockwave generator.
[0127] In a preferred embodiment, the tool comprises a 3-dimensional accelerometer array and the locator comprises processing functionality for determining a 3-dimensional location from the output of the accelerometer array.
[0128] In another preferred embodiment, the tool is attached to a robot arm for movement within the obscured region, and the locator comprises functionality for tracing positioning of the robot arm. The arm is typically segmented and the locator comprises position detectors at each segmentation so that it can accurately find the tool tip position.
[0129] The obscured region is typically an intra-cavity region of a human or animal body.
[0130] In the preferred embodiments, the locator dynamically updates the tool tip position, thereby to provide dynamic following of the tool. Typically, the locator updates the location following movement of the scanning unit.
[0131] According to a second aspect of the present invention there is provided apparatus for precision location of a tool within an obscured region, the apparatus comprising:
[0132] a planar scanning unit for scanning planes within the obscured region using an imaging scan, and
[0133] a locator, associated with the scanning unit, for determining a location of the tool, and for controlling the scanning unit to follow the tool.
[0134] Preferably, the locator is arranged to determine a location of a tip of the tool.
[0135] According to a third aspect of the present invention there is provided a method of imaging a tool in an intra-body space comprising: scanning the intra-body space, locating the tool, and using the locating to control the scanning to follow the tool.
[0136] Preferably, scanning comprises planar scanning and controlling comprises selecting a scan plane to include at least a tip of the tool within a region to be scanned.
[0137] Preferably, scanning is three-dimensional planar scanning comprising scanning using a plurality of planar scans, and controlling comprises including at least a tip of the tool within regions to be scanned of at least two of the scan planes.
[0138] Additionally or alternatively, scanning is three-dimensional planar scanning comprising scanning a plurality of planes within the volume and controlling comprises selecting from the plurality, scans including the tip.
[0139] Additionally or alternatively, scanning is three-dimensional planar scanning, and controlling comprises selecting a plurality of scan planes in different orientations meeting at the location, for scanning.
[0140] Preferably, the process of locating includes providing the tip with recognizability within a scan, for example for ultrasound, one way of providing recognizability is to introduce a bubbled fluid into the tip.
[0141] Whatever form of recognizability if provided, the tip can then be identified using image processing, sensitized to the specific form of recognizability.
[0142] Other forms of introducing recognizability include using ultrasound contrast agent, ultrasound reflection material, and an active ultrasound signal producer.
[0143] Again, recognizability may comprise a signal beacon mounted on the tool, and corresponding locating comprises sensing a signal from the signal beacon.
[0144] Locating may comprise providing multi-position interference signaling and at the tool receiving the signals and calculating co-ordinates relative thereto.
[0145] In one embodiment locating comprises measuring accelerations in respective dimensions at the tool and calculating a location therefrom.
[0146] In one embodiment, the tool is located on a movable robot arm and locating comprises tracking movement of the robot arm.
[0147] The method is preferably used for locating the tool within an obscured body region, and scanning comprises scanning at least partly from outside the obscured body region using a type of scan transparent to body tissues.
[0148] One preferred embodiment utilizes user interaction to locate a feature in the scan, finding three-dimensional co-ordinates of the feature and then controls the scanning to scan the feature during subsequent movement.
[0149] An alternative embodiment utilizes user interaction to locate a feature in the scan, and then uses image processing to follow the feature and control the scanning to scan the feature.
[0150] According to a fourth aspect of the present invention there is provided a method of imaging a tool in an intra-body space comprising: determining a location of the tool in three dimensions, and using the location to control planar scanning to follow the tool by including the tool in at least one plane being scanned.
[0151] Preferably, the controlling comprises selecting the at least one plane being scanned to include a tip of the tool within an area of the plane being scanned.
[0152] Preferably, the scanning is three-dimensional planar scanning comprising scanning using a plurality of planar scans, and the controlling comprises including at least a tip of the tool within regions to be scanned of at least two of the planes being scanned.
[0153] Preferably, scanning is three-dimensional planar scanning comprising scanning a plurality of planes within the volume and controlling comprises selecting from the plurality, scans including the tip.
[0154] Additionally or alternatively, scanning is three-dimensional planar scanning, and controlling comprises selecting a plurality of planes to be scanned in different orientations meeting at the location, for scanning.
[0155] Preferably, scanning comprises providing the tip with recognizability within a scan.
[0156] Preferably, locating is achieved by applying image processing, sensitized to the recognizability, to the scanning, to recognize the tip.
[0157] Preferably, recognizability comprises applying ultrasound contrast agent, ultrasound reflection material, or an active ultrasound signal producer to the tool tip to assist with automatic recognition.
[0158] In a preferred embodiment, mounting a signal beacon on the tool may confer recognizability, and locating comprises sensing a signal from the signal beacon.
[0159] In a preferred embodiment, determining a location comprises providing multi-position interference signaling and at the tool receiving the signals and calculating coordinates relative thereto.
[0160] Additionally or alternatively, determining a location comprises measuring accelerations in respective dimensions at the tool and calculating a location therefrom.
[0161] Additionally or alternatively, the tool is located on a movable robot arm and the determining a location comprises tracking movement of the robot arm.
[0162] Typically the tool is located within an obscured body region and scanning is preformed at least partly from outside the obscured body region using a type of scan transparent to body tissues.
[0163] The method may utilize user interaction to locate a feature in the scan, finding three-dimensional co-ordinates of the feature, and then control the scanning to follow and continue to scan the feature.
[0164] Additionally or alternatively, the method may utilize user interaction to locate a feature in the scan, and then use image processing to follow the feature and control the scanning to scan the feature.
[0165] According to a fifth aspect of the present invention there is provided a surgical tool for use with ultrasound imaging, the tool comprising a a region of high contrast to ultrasound about a tip of the tool.
[0166] Preferably, the region of high contrast comprises a fluid reservoir connected between a fluid inlet and a fluid outlet, into which a bubbled fluid is injectable.
[0167] According to a sixth aspect of the present invention there is provided a surgical tool for use with ultrasound imaging, the tool comprising a a region of automatically variable contrast to ultrasound about a tip of the tool. Preferably, the region of automatically variable contrast comprises a fluid reservoir connected between a fluid inlet and a fluid outlet, into which a bubbled fluid can be injected.
[0168] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples provided herein are illustrative only and not intended to be limiting.
[0169] According to actual instrumentation and equipment of preferred embodiments of the method and system of the present invention, certain steps such as scanning control and image processing may be implemented by hardware or by software on any operating system of any firmware or a combination thereof. For example, as hardware, selected steps of the invention could be implemented as a chip or a circuit. As software, selected steps of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In any case, selected steps of the method and system of the invention could be described as being performed by a data processor, such as a computing platform for executing a plurality of instructions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0170] The invention is herein described. by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.
[0171] In the drawings:
[0172] [0172]FIG. 1 is a generalized schematic diagram showing a tool location apparatus according to a first preferred embodiment of the present invention;
[0173] [0173]FIG. 2A is a simplified schematic diagram showing a series of parallel scanning planes;
[0174] [0174]FIG. 2B is a simplified schematic diagram showing the series of parallel scanning planes as produced using a hand-held scanner;
[0175] [0175]FIG. 2C is a simplified schematic diagram showing the series of parallel scanning planes as produced using a mechanically operated scanner;
[0176] [0176]FIG. 3A is a simplified schematic diagram showing two non-parallel scanning planes;
[0177] [0177]FIG. 3B is a simplified diagram showing a series of non-parallel scanning planes produced by rotation of a standard scanner;
[0178] [0178]FIG. 3C is a simplified diagram showing a series of non-parallel scanning planes produced by a rotary scanner;
[0179] [0179]FIG. 4 is a simplified schematic diagram showing an image of a body cavity with a surgical tool inserted therein, from which the location of the tool may be determined by image processing, operative in accordance with a preferred embodiment of the present invention;
[0180] [0180]FIG. 5 is a simplified schematic diagram showing a tool in a body cavity and having a beacon to assist with location, operative in accordance with a preferred embodiment of the present invention;
[0181] [0181]FIG. 6 is a simplified schematic diagram showing a tool in a body cavity having a receiver for receiving signals from a multi-transmitter positioning system, operative in accordance with a preferred embodiment of the present invention;
[0182] [0182]FIG. 7 is a simplified diagram showing an alternative embodiment, operative in accordance with a preferred embodiment of the present invention, of the tool of FIG. 6 in which one of the multi-transmitter positioning system transmitters is located on the tool and the receiver is located elsewhere;
[0183] [0183]FIG. 8 is a simplified diagram showing a tool in a body cavity having an array of accelerometers for position determination, operative in accordance with a preferred embodiment of the present invention;
[0184] [0184]FIG. 9 is a simplified schematic diagram showing a tool in a body cavity held by a robot arm and wherein the position of the tool is determined by measuring angles at the joints of the robot arm, operative in accordance with a preferred embodiment of the present invention;
[0185] [0185]FIG. 10 is a simplified flow chart showing a method of scanning a body cavity and using image processing to determine a tool location, operative in accordance with a preferred embodiment of the present invention;
[0186] [0186]FIG. 11 is a simplified flow chart showing a method of scanning a body cavity using a tool location scheme separate from imaging of the scan, operative in accordance with a preferred embodiment of the present invention;
[0187] [0187]FIG. 12 is a simplified flow chart showing a method of 3-D scanning of a body cavity and using image processing to determine a tool location, operative in accordance with a preferred embodiment of the present invention; FIG. 13 is a simplified flow chart showing a method of 3-D scanning of a body cavity using a tool location separate from imaging of the scan, operative in accordance with a preferred embodiment of the present invention;
[0188] [0188]FIG. 14 is a simplified diagram showing a surgical tool with a contrast intensifier for location by an ultrasound scanner according to a preferred embodiment of the present invention;
[0189] [0189]FIG. 15 is a simplified diagram showing another surgical tool having a bubble canal contrast intensifier according to another preferred embodiment of the present invention;
[0190] [0190]FIG. 16 is a simplified diagram showing the tool of FIG. 15 in greater detail;
[0191] [0191]FIG. 17 is a simplified diagram showing the tool of FIG. 15 at a different angle; and
[0192] [0192]FIG. 18 is a simplified diagram showing a scanner for obtaining scan planes according to a preferred embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0193] The present embodiments describe a method and apparatus for carrying out selected planar image scanning, to support and improve scanning orientation for surgery using a surgical tool located within target tissue. The embodiments determine the position of the tool or tool tip and ensure that the selected and presented image scanning is carried out in a plane that includes the tool or tool tip. In one embodiment, the actual scanning co-ordinates are used in combination with image processing of the scan in order to locate the tool.
[0194] The present embodiments may for example support real-time sonography using multi planar scanning techniques, based on a three dimensional dataset. The embodiments may be useful for example in providing automatic guidance during intrauterine surgical procedures. The embodiments may use real-time tracking and automated identification of a surgical tool, and provide the surgeon with real-time visualization of the operation target as well as the applied surgical tool within the treatment area, for example a uterine cavity.
[0195] The embodiments may diagnose or treat uterine abnormalities , or may for example guide the needle tip during amniocentesis more effectively than in the prior art by providing full tracking of the tool in use, and other areas of interest, during treatment.
[0196] The invention allows procedures to be performed in the clinic by any gynecologist or surgeon with general expertise in ultrasonography.
[0197] The embodiments eliminate the need for blind surgical procedures under general anesthesia, and thereby reduce complications and improve accuracy. Reduction in complications leads to lower overall cost, and the embodiments specifically provide a solution to many patients for whom blind surgical procedures are considered too risky.
[0198] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.
[0199] Referring now to the drawings, FIG. 1 is a simplified diagram showing a tool tip location apparatus operative in accordance with a first embodiment of the present invention. A tool 10 is located within an obscured region such as an internal body cavity or organ 11 for the purpose of carrying out an operation. A planar scanning unit 12 is located anywhere and scans the targeted area. The scanning unit 12 scans two-dimensional planes within the cavity or organ, and a three-dimensional scan image may be built up by computing the planes together. In order to carry out the operation the surgeon requires detailed information of the location of a tip 14 of the tool and, as discussed above in the background, it is difficult for a surgeon to keep the scan accurately focused on the tool tip 14 , that is to say it is difficult to ensure that the tool tip always falls within a plane being scanned. In addition it is tricky to simultaneously ensure that the area being treated is reasonably well imaged. It is further difficult to coordinate simultaneously both the scanner and the tool together on the same plane. There is thus provided a locator 16 , which is able to determine the location of the tool in three dimensions within the cavity or within the organ. The locator 16 may use any suitable method of locating the tool, and several examples are given below. The locator 16 is integrated within the scanning unit 12 and uses the tool tip location (or other selected features) to improve the scanning results.
[0200] Improvement of the scanning results may be achieved in any one of a number of ways. Firstly, with reference to FIG. 2A, showing a series of parallel original (not computed )planes 18 a , 18 b , and 18 c , the scanner may select a plane ( the closest one) that includes the tool tip or other selected regions, from the series of planes already scanned, for emphasis. Thus a selected plane found to have the tool tip included therein may provide the surgeon with more detail information regarding the treated area and the location of the selected tool in that specific area. As will be explained below, in addition to the tool tip, in some of the embodiments it is possible to define and lock on to tissue features as well, so that several planes could be emphasized in a scan, one for the tool and one each for a series of user identified features.
[0201] Secondly, with reference to FIG. 3A, the scanner may select a series of nonparallel planes (or computed planes ) 19 a , 19 b , that meet at the location of the tool tip, and then control the scanner to scan the series of planes. Thus, in this second method a spherical volume is acquired, in a series of fan-shaped sections of the sphere, with the tool tip at the center. In fact the figure shows only two such planes, and in a preferred embodiment of the present invention one image plane is selected to show the line, that is the longitudinal axis, of the surgical tool, and the other image plane is selected to show the tool tip as a point where it contacts the surrounding tissue. Planes may also be selected to show relationships between different tools or different features. If several planes are used then image processing techniques known to the skilled person can be used to fuse data from the planes to form a 3D image.
[0202] [0202]FIG. 2B shows how a series of planes may be gathered by movement of a scanner 21 . In FIG. 2B the scanner is moved by hand and thus the orientation and the spacings of the scan are irregular. In FIG. 2C the scanner is mechanically controlled, freeing the surgeon or his assistant from having to orient the scanner. In the mechanical version, regular spacings are achieved, but at the cost of control over the scanner. The present embodiments, by inputting the location of the tool to the scanner to set scan positions, provide the advantages of hand and machine scanning together.
[0203] [0203]FIG. 3B shows how scanner 21 can be rotated to give a series of non-parallel scan planes as in FIG. 3A. FIG. 3C shows a rotary scanner 23 which may be rotated automatically to provide a series of non-parallel planes describing a spherical volume.
[0204] A plane that is selected may thus be the plane that includes the tip of the surgical instrument being used. Now the surgeon may be using a three-dimensional model for viewing during the surgery, and in one embodiment, the surgeon is able to project the model onto the patient himself. In another embodiment the three dimensional view may be integrated with the surgeon's view. Such embodiments are useful for intraoperative anatomy exploration, orientation and manipulation, and may also be used in telesurgery systems, where the surgeon controlling the operation is remote from the patient. 3-D image modeling is widely used in neurosurgery in which a 3-D imagebased model of the brain may be presented to the surgeon in a realistic form through the use of stereoscopic displays. Using the display the surgeon is able to more accurately localize the target and plan the trajectory of approach while avoiding sensitive structures.
[0205] Fusion techniques can be used and the real world of the operating room (via stereoscopic video images) and the digital MR image of the patient's operation target area, such as uterus or brain may be merged in order to allow the surgeon to visualize the target prior to surgery. A similar procedure using a laser scanner to image the cortical surface may also be used to track the shift of the brain during open craniotomies.
[0206] The system of the present embodiments may be used in combination with visual or other forms of feedback. Feedback of the kind used in surgery is well-known if not currently greatly utilized.
[0207] Medical images are visual representations of solid structures with different mechanical, textural and functional properties. Even when cursor probes are provided to interrogate the volume, the cursor is generally allowed to roam freely through the volume and there is no feedback to the operator to prevent him from moving beyond organ or tissue, or at least to sensitize him to the fact that such boundaries exist. On the other hand, a clinician who examines an organ, either in-vivo or in-vitro, relies as much on tactile feedback as he does on its appearance.
[0208] Until recently, work in the area of providing tactile feedback to enhance the interpretation of medical images has been limited by the speed of generally available computational facilities. Nevertheless, some recent preliminary studies have demonstrated the efficacy of combining 3-D imaging with hepatic interfaces in these circumstances. The use of such an interface in the context of IGNS is considered, particularly to facilitate the positioning of modeled lesions, as well as navigating within the brain with stimulation or lesioning probes, and endoscopes. In each case, tactile feedback, in the form of forces or vibrations, are relayed to the surgeon via a computer-linked, hand-held device. Tactile feedback alerts the surgeon in a natural manner when a proposed lesion position is dangerously close to a critical structure, or when a probe or endoscope is about to enter dangerous territory, for example is about to perforate the ventricular wall.
[0209] The addition of tactile feedback to instruments used in image-guided surgery can add an extra layer of confidence to the procedure, by warning or preventing the surgeon from placing a surgical tool in a region considered dangerous, based on analysis of pre-operative 3D medical images
[0210] In practising the present invention, the skilled person may come across multimodal registration problems. That is to say major differences in the settings needed and quality of data may arise. Such differences may be due to the type of data to be matched to form the images, the anatomy to be imaged, specific clinical requirements of the particular procedure being supported, and the signal being provided by the surgical tool. Also, differences in registration success may depend on what feature is being looked at. Some features may be easier to locate and follow than others. The user wishes to achieve accurate, steady and repeatable 3D positioning.
[0211] Reference is now made to FIG. 4, which is a simplified diagram showing a scan image 20 having a tool 22 with a tool tip 24 located amongst some body tissue 26 being the subject of the operation. The locator is an image processor which is configured to process the scan image to recognize the tool. Recognition of the tool may be achieved in a number of ways. For example the tool tip 24 may be made of, or at least be coated with, a substance selected to provide a contrast in the scan over the surrounding tissue 26 . Thus the image processor simply looks for the region of high contrast and takes that as the location of the tool tip. For ultrasound scanning there are commercially available contrast agents that can be used to coat the tool or tool tip. As an alternative a reflection contrast agent may be used, again to coat the tool or tool tip. For other forms of scanning there are equivalent substances.
[0212] The above-described agents all provide passive tool tip location. It is also possible to provide active tool location, and the tool may be fitted with an active ultrasound generator, for example a high frequency magnet-based vibrator type transmitter 28 . Upon activation of the transmitter, the tool tip emits an specific ultrasound signal, which may be picked up by the current scan, and processed by the image processor in the same way as the high contrast point of the passive location embodiment.
[0213] An advantage of the embodiments described with respect to FIG. 4 are that, since ultrasound is used as the tool location medium, via the scanned images themselves, the determined location of the tool tip is automatically coordinated with the scan. When the tool tip, or any other requested site, is found by the image processor in a given scanned plane, then if the scanned plane is the x, y, plane, the scanner is able to provide the z co-ordinate, and the image processor provides the x and y co-ordinates.
[0214] In addition to identifying and locating the tool, the locator is also able to identify and locate a feature in the targeted tissue. The operator may recognize a tissue feature of interest in the scan and flag it as a point of interest. Flagging may be carried using a mouse and cursor or using a touch screen or by any other suitable method. The locator is able to find the z-axis of the scan plane being considered, and the user selection provides x and y co-ordinates. Subsequently, movement of the feature may be tracked by image processing or the system may simply assume that the body is at rest and continue to image the same co-ordinates. Active tracking of the feature of interest is advantageous in that it compensates for involuntary body movements including pulse and breathing related movements, which can be significant in relation to the scale of features involved in some types of operation.
[0215] Reference is now made to FIG. 5, which is a simplified diagram showing a further embodiment of a tool location apparatus according to a further preferred embodiment of the present invention in which image scanning and tool location are carried out using separate media. Tool 32 , has a tool tip 34 which is located against body tissue 36 on which an operation is to be performed. Located in association with the tool tip 34 is a beacon 38 , which emits a signal allowing it to be located in three dimensions. Sensing apparatus 40 , senses the signal and determines the co-ordinates (x,y,z) of the tool, which co-ordinates are then used by the scanning unit 42 to scan in the region of the tool tip. The signal used by the beacon may be any signal that is able to exit the cavity and may include radio, x-ray, and ultrasound signals. If an ultrasound signal is used, however, it is generally easier to use the ultrasound image scanner for detection as described in respect of FIG. 4 above, rather than to install a separate location sensor as per the present embodiment.
[0216] Reference is now made to FIG. 6, which is a simplified alternative embodiment for providing a location of a tool tip according to the present invention. Parts that are the same as those in previous figures are given the same reference numerals and are not referred to again except as necessary for an understanding of the present embodiment. The locator comprises a multi-transmitter remote positioning system, similar to the global positioning system except on a vastly smaller scale. The positioning system comprises a series of transmitters 50 , 52 , 54 , each emitting a signal. The tool 32 comprises a receiver 56 which receives the signals from each of the transmitters. The received signals are compared and a position is determined relative to the transmitters. The determined position is then relayed to the scanning unit as before.
[0217] The positioning system may make use of any kind of electromagnetic waves including RF, magnetism, microwave, infra-red, light, ultra-violet, and x-ray. Light may involve following of LEDs located on the tool, or image processing to follow the tool or other known object. Magnetism may involve the placing of a magnet on the tool and sensing changes in magnetic field as a consequence of moving the tool. If the tool is being used in an intra-body cavity or other obscured location then the skilled person may take care to ensure that the positioning system uses a part of the spectrum that is able to penetrate the obscuring material. Aside from electromagnetic waves the positioning system may use ultrasound, shock waves or any other suitable kind of wave.
[0218] With further regard to the use of magnetism, such magnet-based technology, known as electromagnetic (EM) surgical navigation, is transparent to the user, and transparent to the procedure type. Line-of-sight restrictions are eliminated, as well as the need for any change in surgical flow or technique. An algorithm known as Magneticlntelligence™, of General Electric Corporation, automatically detects and compensates for metal in the field, improving accuracy.
[0219] The use of electromagnetism together with planar imaging in accordance with the above-described embodiments provides three-dimensional visualization of a patient's anatomy, and the ability to track the position and orientation of instrumentation during surgery.
[0220] Reference is now made to FIG. 7, which is a simplified diagram showing a variation of the embodiment of FIG. 6. Parts that are the same as in FIG. 6 are given the same reference numerals and are not described again except to the extent necessary for an understanding of the present variation. The multi-transmitter positioning system includes a transmitter 57 located in the region of the tool tip. A receiver 58 is located away from the tool. The receiver 58 receives signals from each of the transmitters and uses phase differences and other contrasts between the signals to determine the position of the tool tip in three dimensions. That is to say, instead of providing a receiver on the tool, a transmitter is provided on the tool, and a receiver compares between signals from the moving tool tip and from stationary transmitters. An advantage of the variation of FIG. 7 is that the tool does not have to have access to processing power. By contrast the receiver on the tool of FIG. 6 must be able to compare received signals or transfer them to another location able to carry out a comparison without distorting phase information.
[0221] Reference is now made to FIG. 8, which is a simplified schematic diagram showing a further preferred embodiment for obtaining a tool location, operative in accordance with the present invention. Parts that are the same as those in previous figures are given the same reference numerals and are not referred to again except as necessary for an understanding of the present embodiment. In the embodiment of FIG. 8, tool 32 comprises an accelerometer array. The array comprises three accelerometers placed mutually perpendicularly to each other, as shown by arrow arrangement 62 , so as to record acceleration in three dimensions. The tool begins each operation or part thereof at a predetermined starting point, and then tracking of the acceleration is subsequently sufficient to provide accurate positioning. The embodiment of FIG. 8 is advantageous in that it does not require any kind of radiation since signals from the accelerometer can be wired directly to the scanner.
[0222] In all of the above embodiments, the tool 32 may be hand held by the surgeon or it may be manipulated by a robot arm. If manipulated by a robot arm then the system can be used in providing remote surgery. Reference is now made to FIG. 9, which is a simplified schematic diagram showing a location system specifically suited to cases in which the tool 32 is mounted on a robot arm 70 . The robot arm comprises a series of arm sections 72 , 74 , 76 with joints 78 , 80 in between. At each joint one or more rotation sensor determine the current joint rotation, allowing the position of the end of the arm and thus of the tool to be determined. In general each individual joint can rotate in two dimensions and requires two sensors to measure and fully define the rotation. The sensors may typically be potentiometer-based sensors. An advantage of the embodiment of FIG. 9 is that robot arms comprising such sensors are available as off-the-shelf components, allowing for convenient implementation.
[0223] As mentioned above, the system is suitable for following a tool for use in an obscured region. The obscured region may be an intra-body or intra-body cavity region of a human or animal. Scanning systems for scanning intra-body regions are well-known but often because of the planar nature of scanning it can be difficult to keep track of a tool tip being used in an operation. The tip tracking disclosed hereinabove allows the scanning to automatically track the tool tip, thus allowing the surgeon to focus attention on the operation itself.
[0224] In a further preferred embodiment of the present invention, the tool locator 16 dynamically updates the tool position as the tool moves, say in the course of carrying out an operation. The updates can then be fed to the scanning system to direct the next scan and thus provide dynamic following of the tool.
[0225] Likewise the tool position can be dynamically followed for imaging purposes following movement of the scanner. The surgeon may wish to view the tool and surrounding tissue from different angles or from different distances. Currently, movement of the scanner is tricky because the surgeon has to find a plane that includes the tool tip every time the scanner is moved. With the tool locater system 16 taking over such a plane finding function, scanner repositioning becomes much simpler and the repositioned scanner simply uses the latest co-ordinates of the tool tip.
[0226] Reference is now made to FIG. 10, which is a simplified diagram showing a method of imaging a tool, for example in an intra-body cavity. The method comprises scanning the intra-body cavity using any suitable scanning method, including ultrasound, magnetic resonance imaging, CT scans and the like. A tool or other foreign body is located within the cavity in three dimensions and then the location is used to direct the scanner to include the tool in its scan. As discussed above, the tool may typically be a surgical tool carrying out an operation. Many scans are planar scans which scan flat planes, and it generally requires significant skill on the part of the surgeon to obtain a scanning plane that actually includes the working tip of his tool. At best the attempt to include the working tip is a significant distraction for the surgeon. In one variation the scan itself is used to identify the tool. Thus in the initial stages the tool tip has to be found manually. Once the tool tip has been found it is identified from the scan by image processing and a location is derived. Then the scanner is controlled to follow the tool tip. As mentioned above, it is possible to enhance recognizability of the tool for the image processor by coating the tool with a contrast agent or a reflection agent. Alternatively an active source on the tool may be used to illuminate the tool in the image.
[0227] Upon recognition of the tool or tool tip, the system may select a particular plane including the tool for emphasis. Alternatively it may choose a series of nonparallel planes to scan that each include the tool location.
[0228] In a preferred embodiment, the scan is an ultrasound scan and image processing operates on an ultrasound image capture to identify and locate the tool.
[0229] Reference is now made to FIG. 11, which is a simplified flow chart showing a variation of the method of FIG. 10. In the method of FIG. 11, the location and scanning systems are separate in that obtaining the location of the tool in three dimensions is carried out separately from processing of the scan. In such a case the tool location is firstly determined, using any of the methods detailed with respect to FIGS. 5 - 9 or any other suitable method. Tool location may for example be achieved by receiving transmissions from a beacon located on the tool, at a plurality of locations, and processing the transmission to determine its co-ordinates in three dimensions. As an alternative, discussed with respect to FIG. 6 above, a set of transmitters may be placed around the tool and a receiver placed on the tool. The signals received at the tool receiver may be used to determine the tool's location in three dimensions.
[0230] As a further alternative, discussed with respect to FIG. 7 above, one or more transmitters may be located around the tool and a further transmitter on the tool. A receiver may be positioned away from the tool. Location is achieved by comparing signals from the tool and the other transmitters.
[0231] A further alternative, discussed with respect to FIG. 8 above, provides for an array of acceleration sensors on the tool to provide acceleration data, from which the current position of the tool can be traced.
[0232] Following location of the tool, a scan plane is selected that includes the tool, and then the selected plane is scanned. Thus a scan is produced that automatically includes the tool. Thus the surgeon is provided with a view that shows the tool he is working with. As discussed above, the scan may dynamically follow movements of the tool or alternatively may dynamically compensate for movements of the scanner. for example if the surgeon wishes to scan from a different angle or get closer to his subject.
[0233] Reference is now made to FIG. 12, which is simplified flow chart showing a variation of the method of FIG. 10 specifically for producing a three-dimensional scan. A volume of interest is scanned and image processing is applied to the scanned planes to locate the tool or tool tip. The ability to locate the tool using image processing may be enhanced by using any of the methods described above, including using a suitable contrast agent or reflection agent. Once the tool has been located then an arrangement of planes is selected to obtain a volume about the tool and to follow the tool.
[0234] Likewise it is possible to indicate to the system a region of interest on the image, for example a feature in the tissue. The feature may be indicated by pointing using a cursor or any other suitable method. The locator may simply record the three-dimensional co-ordinates of the feature and continue to scan at those coordinates or it may apply image processing to follow the tissue feature. The latter is useful if the tissue moves, however there is a limit to tissue features that are suitable for following by image processing.
[0235] Reference is now made to FIG. 13, which is a simplified flow chart showing a variation of the method of FIG. 11 specifically for forming a three-dimensional scan. The tool location is found as described hereinabove in accordance with any of the methods of FIGS. 5 - 9 , and the location information is used to select planes for scanning that include the tool. Tool location may for example be achieved by receiving transmissions from a beacon located on the tool, at a plurality of locations, and processing the transmission to determine its co-ordinates in three dimensions. As an alternative, discussed with respect to FIG. 6 above, a set of transmitters may be placed around the tool and a receiver placed on the tool. The signals received at the tool receiver may be used to determine the tool's location in three dimensions.
[0236] As a further alternative, discussed with respect to FIG. 7 above, one or more transmitters may be located around the tool and a further transmitter on the tool. A receiver may be positioned away from the tool. Location is achieved by comparing signals from the tool and the other transmitters.
[0237] A further alternative, discussed with respect to FIG. 8 above, provides for an array of acceleration sensors on the tool to provide acceleration data, from which the current position of the tool can be traced.
[0238] Following location of the tool, the selected planes are scanned and an image produced. The process is repeated with the tool location being redetermined. If the tool is found to have moved then new planes are selected and so-on. Thus the system succeeds in dynamically following the progress of the tool through the operation.
[0239] In a preferred embodiment of the present invention, image analysis or any of the other methods of tool plane tracing may be carried out in a tracing mode whereas regular scanning is carried out in a scanning mode. The scanner may, at the user's direction pass from one mode to the other. Thus the user may transfer from volume acquiring to tracing mode or vice versa. In tracing mode the scanner may lock on to the tool tip or any other point being indicated and then return to volume acquiring mode proceed to acquire volume whilst following that point so as to constantly include that point in an image plane. Tracing mode may be carried out as discussed above using signal processing or image processing techniques. The embodiment allows computerized movement to replace hand guiding of the scanner. The scanner may nevertheless be handheld, and the locking on feature may allow for compensation for inadvertent hand movements.
[0240] Reference is now made to FIG. 14, which is a simplified diagram showing a tool suitable for use with the embodiments of the present invention. Tool 90 is any kind of invasive tool whose location can be used to control or follow the progress of an operation, and examples include curettes, including the Sims Curette and the Hunter curette, uterine aspiration curettes, both curved and straight, uterine dilators including the Hegar dilator, the Pratt dilator and the Hank dilator, and sponge forceps, including the Foerster, and DeLee ovum forceps.
[0241] A point, 92 , is selected, preferably as a point that carries out the surgical procedure or the point nearest to the tissue on which the procedure is being carried out, and the point is then marked or signed so that it can be followed. Marking or signing may be carried out using any suitable method, in particular the methods outlined hereinabove.
[0242] Reference is now made to FIG. 15, which is a simplified diagram showing a surgical tool according to a further preferred embodiment of the present invention. Surgical tool 94 may be any kind of surgical tool. The tool comprises an internal pipe or canal structure 96 that normally contains water. A pump 98 is connected to the tool via connector 100 to pump water into the canal 96 . The pump includes a bubble chamber which allows the pump to introduce bubbles into the canal. Bubbles show up brightly with ultrasound and thus the combination of ultrasound and a tool having a bubble canal provides a simple method of allowing the ultrasound to follow the tool. As bubbles can be introduced rapidly, the bubble canal provides a way of achieving high contrast on demand.
[0243] Reference is now made to FIG. 16, which is a simplified diagram showing the tool of FIG. 15 in greater detail. The tool 94 comprises an outer wall 110 into which canal 96 is built. The canal has an outward leg 112 connected to an outlet of the pump connector and a return leg 114 connected to an inlet of the pump.
[0244] Reference is now made to FIG. 17, which is a simplified diagram showing a further view of the tool of FIG. 16. Parts that are the same as in previous figures are given the same reference numerals and are not described again except to the extent necessary for an understanding of the present figure. At the operative end 116 of the tool 94 the canal forms a reservoir region 118 in order to render itself identifiable to the image processing system referred to above.
[0245] Reference is now made to FIG. 18, which is a simplified diagram showing a scanner obtaining scans of a region of interest. The scanner first scans a series of planes in order to locate a target, such as a tool tip. A plane of interest is identified from the scanned planes using image analysis. Then the scanner locks onto the plane of interest. However the target moves so, whenever the image of the tool grows faint it scans around the current plane of interest to identify a new plane of interest.
[0246] The embodiments described above are useful in any kind of activity wherein imaging is needed to see what is happening and interactive feedback is required. Particular applications in the medical field include gynecology and uterine surgery, obstetrics and amniocentesis, chorionic villi sampling, breast biopsy, neurosurgery, orthopedics, maxillofacial, craneofacial and dental surgery, laparoscopic and endoscopic surgery, radiotherapy, and specific procedures in ophthalmology.
[0247] It is expected that during the life of this patent many relevant forms of beacon, sensing, and location technology will be developed and the scope of the terms “beacon”, “sensor” and “locator” is intended to include all such new technologies a priori.
[0248] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.
[0249] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.
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Apparatus for precision location of a tool such as a surgical tool within an obscured region such as an internal space of the human or animal body, the apparatus comprising: a planar scanning unit for scanning planes within said obscured region using an imaging scan, and a locator, associated with said tool and with said scanning unit, for determining a location of said tool, and for selecting a plane including said tool location. The apparatus allows the planar scan to follow the tool automatically and saves skill and effort on the part of the surgeon.
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This invention relates to a maneuvering wheel for a wheelchair, and more particularly to a maneuvering wheel for a wheelchair or a similar apparatus, which permits movement in a different direction, without moving the mounting for the maneuvering wheel, about the mount therefor.
BACKGROUND OF THE INVENTION
Wheeled carts, which are usually human propelled, have in common problems with a very restricted movement for the front wheels, thereof. The front wheels generally serve as maneuvering wheels or steering wheels. In the medical industry, typical examples of such wheeled carts are gurneys, laptop carts, cabinets and beds; to name a few. Currently, the front wheels of these wheeled carts must swivel 180 degrees in order for the particular wheeled cart to move in an opposite direction. For general consumer goods, items like dollies for moving heavy equipment, and grocery carts have problems such restricted movement of the wheels. However, this restricted movement is especially a problem with a wheelchair.
A wheelchair is chair with wheels, designed for use by a person, who either has difficulty with walking or cannot walk. Within the mechanics of a wheelchair are mounted a pair of support wheels, generally in the rear; and a pair of steering wheels or maneuvering wheels, generally in the front to support a chair or seat for a person, who has difficulty walking. With the two pair of wheels, the wheelchair is stable. With the support wheels and the steering, that is the front, wheels working to support the chair, that person in the chair can move or be moved to a desired location.
Currently, the front wheels of a wheelchair must swivel 180 degrees in order for the wheelchair, or similar apparatus, to move in an opposite direction. This requirement results in a number of problems. There is a problem with the storage of the wheelchair. There is another problem when the wheel chair contacts a soft floor surface. More complications occur when the wheelchair, especially with the passenger therein, is in a confined area.
The support wheels of one type of wheelchair for a human or person-propelled wheelchair usually rotate together on a common axle. In this case, the support wheels can be reached by the arms of the person sitting in chair. As the arms move the support wheels, the person in the chair can move to a location. By propelled in this manner is meant that the person sitting in the chair can propel the chair with arm strength by using the support wheels.
For a transport chair, the patient cannot propel the wheelchair with arm strength; but must either use foot and leg strength or be pushed by another person. The support wheels may be on the same axle, or each support wheel may be on a separate axle. The support wheels are generally too small to be reached by the arms of the person sitting on the seat portion of the chair.
On the other hand, each member of the pair of steering wheels rotates on its own axle, which is mounted within an axle housing. The axle housing itself also rotates also to provide steering for wheelchair, and has its rotation preferably perpendicular to the rotation of the support wheel axle.
Such a structure for steering wheels limits movement and steering of the wheelchair. Due to the usually perpendicular arrangement of the axles for each steering wheel, the steering wheels can and do work at cross purposes and against an efficient use of the wheelchair. It is very desirable to achieve more free movement for the maneuvering wheels for use efficiency, while maintaining or improving the utility of the wheelchair.
SUMMARY OF THE INVENTION
Among the many objectives of the present invention is the provision of a steering wheel for a wheelchair, which has a spherical support member that can move freely in a housing.
Another objective of the present invention is the provision of a steering wheel for a wheelchair, which has reduced complications with a second steering wheel for the wheelchair.
Yet another objective of the present invention is the provision of a steering wheel for a wheelchair, which simplifies movement of the wheelchair.
Still another objective of the present invention is the provision of a wheelchair, which has a spherical support member that can move freely in a housing for each of its steering wheels.
A further objective of the present invention is the provision of a wheel, which the wheeled device on which it is mounted can move easily on a soft floor.
A still further objective of the present invention is the provision of a wheel, which the wheeled device on which it is mounted can turn from any position, without rotating 180 degrees.
Yet a further objective of the present invention is the provision of a wheel, which minimizes storage problems.
Also an objective of the present invention is the provision of a steering wheel for a wheelchair, which minimizes problems caused by the wheelchair being in a confined area.
These and other objectives of the invention (which other objectives become clear by consideration of the specification, claims and drawings as a whole) are met by providing a steering wheel for a wheelchair, with the steering wheel having a shaft which receives a housing; which housing, in turn, receives a globular ball or globular wheel, with a seal movably holding the globular ball or globular wheel in the housing; and a series of friction-reducing bearings being positioned between the globular wheel or globular ball, and the interior of the housing, and held within the housing and the shaft by the seal in combination with the globular wheel globular ball.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 depicts a perspective view of a steering wheel 100 of this invention in position on a wheelchair 110 .
FIG. 2 depicts an exploded, perspective view of the steering wheel 100 of this invention.
FIG. 3 depicts a plan, assembled, cross-sectioned view of the steering wheel 100 of this invention.
FIG. 4 depicts a block diagram steering wheel 100 of this invention.
Throughout the figures of the drawings, where the same part appears in more than one figure of the drawings, the same number is applied thereto.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to several embodiments of the invention that are illustrated in accompanying drawings. Whenever possible, the same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. The drawings are in simplified form and are not to precise scale. For purposes of convenience and clarity only, directional terms such as top, bottom, left, right, up, over, above, below, beneath, rear, and front, may be used with respect to the drawings. These and similar to directional terms are not to be construed to limit the scope of the invention in any manner. The words attach, connect, couple, and similar terms with their inflectional morphemes do not necessarily denote direct or intermediate connections, but may also include connections through mediate elements or devices.
A wheel suitable for use on a wide variety of human propelled devices has a housing, which receives a globular ball. The top of the housing has a threaded aperture to receive a threaded shaft. Between the globular ball and the interior of the housing are situated ball bearings to provide maneuverability between the housing and globular ball.
Securing the globular ball, and hence the ball bearings, in the housing is a seal. The seal fits into a groove or retainer slot in the housing, thereby containing the globular ball and the ball bearings within the housing.
Into the threaded aperture on the top of the housing, may be inserted a cup separating the shaft from the ball bearings and as the shaft is threaded into the aperture. The cup creates a smooth interior for housing, even with the aperture therein.
However, the shaft preferably has an arc at the end thereof to create that smooth interior for the housing, to avoid the use of the above referenced cup. The opposing end of the shaft can then mount the wheel on a wheel chair or other desired human-propelled, wheeled vehicle. The maneuvering wheel can also used on a self propelled device, having an engine.
A permanent or temporary lubricating composition or coating can replace, or be used in combination with, the ball bearings. The ball bearings provide the most efficient structure.
Now considering FIG. 1 , maneuvering wheel 100 is mounted on wheel chair 110 . Maneuvering wheel 100 permits wheel chair 110 to be moved easily in any desired direction within the plane, on which wheel chair 110 is positioned.
Adding FIG. 2 and FIG. 3 to the consideration, maneuvering wheel 100 has shaft 120 fitting into a bell shaped housing 150 . Shaft 120 has a shim 122 with male housing threads 124 extending therebelow. Shim 122 may be a part of shaft 120 , or added thereto as a separate piece if required for retrofitting of a wheel chair 110 . Oppositely from male housing threads 124 on shaft 120 are mounting threads 126 . Mounting threads 126 permit the mounting of maneuvering wheel 100 on wheel chair 110 on other device.
Within bell shaped housing 150 are situated ball bearings 130 . Ball bearings 130 are held in a movable fashion within bell shaped housing 150 by globular ball 140 . Female threaded aperture 152 in the top of bell shaped housing 150 can receive male housing threads 124 as well as provide a way to insert ball bearings 130 between bell shaped housing 150 and globular ball 140 . Female threaded aperture 152 is preferably has a diameter parallel to diameter of the retainer slot 134 below described.
Male housing threads 124 preferably terminate in a female arc 132 . Female arc 132 is preferably shaped to permit bearings 130 to roll freely between bell shaped housing 150 and globular ball 140 by completing a smooth arcuate surface for the interior 134 of bell shaped housing 140 . Thus, the diameter of female arc 132 permits the interior 134 of bell shaped housing 140 to be a smooth arc facilitating the movement of ball bearings 130 .
Oppositely disposed from female threaded aperture 152 in bell shaped housing 150 is retainer slot 154 . Retainer slot 154 receives seal 160 , to hold both globular ball 140 and ball bearings 130 in bell shaped housing 150 . Shaft 120 also cooperates with seal 160 to hold ball bearings 130 in place. Thus, bell shaped housing 150 is preferably symmetrical about a vertical axis.
Seal 160 includes retainer collar 162 and dust shield 164 . Retainer collar 162 fits into retainer slot 154 and holds globular ball 140 in bell shaped housing 150 . As retainer collar 162 extends into dust shield 164 , bearings 130 can be protected from dust or other contaminants. Then globular ball 140 can move more freely.
Within FIG. 4 , maneuvering wheel 100 is mounted on wheel chair 110 . More particularly, shaft 120 connects bell shaped housing 150 to wheel chair 110 . Bell shaped housing 150 receives globular ball 140 to hold ball bearings 130 . Seal 160 mounts in bell shaped housing 150 and holds globular ball 140 in position. Shaft 120 and globular ball 140 position bearings 130 as desired in maneuvering wheel 100 .
Bearings 130 may be combined with a lubricating coating on the globular ball 140 or in the bell shaped housing 150 . The lubricating coating may be polytetrafluoroethylene, a silicone base, or similar coating. Bearings 130 , however, are more durable and hence preferred.
This application—taken as a whole with the abstract, specification, claims, and drawings—provides sufficient information for a person having ordinary skill in the art to practice the invention disclosed and claimed herein. Any measures necessary to practice this invention are well within the skill of a person having ordinary skill in this art after that person has made a careful study of this disclosure.
Because of this disclosure and solely because of this disclosure, modification of this tool can become clear to a person having ordinary skill in this particular art. Such modifications are clearly covered by this disclosure.
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Wheeled carts, such as a wheel chair and similar devices have a steering wheel, with the steering wheel having a housing to receive the globular wheel, with a seal movably holding the globular wheel in the housing; and a series of friction-reducing bearings being positioned between the globular wheel and the interior of the housing, and held within the housing by the seal in combination with the globular wheel.
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CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This patent application is a continuation of PCT/EP2012/058358, filed May 7, 2012, which claims priority to German Application No. 102011050316.1, filed May 12, 2011, the entire teachings and disclosure of which are incorporated herein by reference thereto.
FIELD OF THE INVENTION
[0002] The invention relates to a method for the decoating at least in part of blanks made of metal which are coated on one or both sides in regions which have a main extension direction, wherein the regions to be decoated can extend in both a straight or curved manner in the main extension direction. The invention further relates to a device for the decoating at least in part of a coated blank in order to carry out the method according to the invention.
BACKGROUND OF THE INVENTION
[0003] To an increasing extent, high strength and super high strength steels are used for example in the automotive industry, as said steels can be provided with lower wall thicknesses resulting in weight advantages. In order to form this material, hot forming is particularly suitable, which however requires additional coating of the blank so that these do not scale in the hot forming tool. An AlSi coating is frequently used. This effectively prevents the scaling of the blank during hot forming, in which the blank is heated at least to austenitising temperature. What is problematic when welding blanks coated in this way is that the components of the coating, in particular aluminium, penetrate the weld region and in the case of hot forming with subsequent press hardening lead to a lack of strength in the welded joint. The regions necessary for the decoating of the blanks have a main extension direction, namely in the direction of the welded seam.
[0004] The width of the regions is preferably limited to a maximum of 5 mm as otherwise the absence of the coating in these regions would in turn have negative consequences.
[0005] There are now various options to remove a coating, in particular an AlSi coating but also any other coating in the region of the welded seam from the blank before welding. These can be divided into thermal, chemical and mechanical methods.
[0006] For example, it is known that the coating in the desired regions can be removed by etching with acid. However, this is very time-consuming as the remaining regions of the blank on which the coating is to remain have to be masked or covered.
[0007] In terms of mechanical methods, longitudinal 2lanning or milling of the coating have been attempted to date. However, both methods are very time-consuming and cost-intensive as the regions of the blank provided for the welded seams have to be worn down separately. In other words, the regions have to be shaved or milled along their main extension direction.
[0008] Furthermore, tests have been carried out which process the affected positions using sandblasting. As a disadvantage, it has been determined that parts of the coating, in particular aluminium, are pressed into the substrate.
[0009] A further method is described in the prior art in which the coating is removed by means of high frequency electromagnetic fields (DE 10 2008 006 624 A1). This method has yet to become established.
[0010] The evaporation of the coatings in these regions using a pulsed laser continues to be used. From the German utility model DE 20 2007 018 832 U1, for example, it is known not to completely remove the coating but rather to leave an intermediate layer known as the inter-metallic intermediate layer, on the substrate, which protects the decoated region from corrosion at least for a time-limited period. This inter-metallic intermediate layer further contains components of the coating such as aluminium. The remaining parts of the coating, for example aluminium, can then penetrate the welded seam. Furthermore, removing the coating using a laser is relatively time-intensive as the entire region has to be decoated along its main extension direction.
[0011] A mechanical method for removing the coating in the region of welded seams is further known from German utility model DE 20 2007 018 832 U1 in which the coating is removed mechanically using brushes. Again the disadvantage is that the entire welded seam has to be worn down with the brushes in order to decoat said welded seams over the entire length. In addition to this, when using the brushes it is not possible to ensure that the coating has been removed completely. All of the previously mentioned methods to remove the coating are very time-consuming and therefore result in relatively high costs.
[0012] On this basis, the object of the present invention is to provide a method which is as simple as possible and a device which is as simple as possible with which the coating of a blank can be removed effectively and cost-efficiently in one operation if possible.
SUMMARY OF THE INVENTION
[0013] In accordance with a first teaching of the present invention, the above mentioned object for a method is achieved by the blank being placed on a blank support of a press and during the closing movement of the press at least one scraping knife preferably completely removes the coating on the blank by scraping in a direction substantially perpendicular to the main extension direction of the region of the blank to be decoated.
[0014] In contrast to the previously known mechanical methods, the removal of the coating of the blank does not take place in a longitudinal direction of the region to be decoated, but rather substantially perpendicular to its main extension direction using a press. Presses are generally frequently used devices for the processing of blanks, so existing devices can be used for the method according to the invention. The decoating is carried out in the press by a working stroke of the press, similarly to a forming process. Low cycle times are achieved in this way, so when decoating for example blanks which are coated on both sides considerable time advantages are achieved. Since the regions to be decoated are substantially decoated perpendicular to their main extension direction, the scraping knife only requires short pathways, for example up to 5 mm, which can be passed through in a very short time. The dimensions of the regions to be decoated may also be larger locally depending on the application. In addition to this, there is no inter-metallic phase, so that particularly good welding results are achieved.
[0015] The method according to the invention is therefore preferably developed by the decoating taking place to provide a welding region, in particular a welded seam region. Thicknesses of more than 0.04 mm are preferably removed during decoating, so that the scraping knife can be used in a particularly reliable manner.
[0016] In accordance with a further embodiment of the method according to the invention, the blank is decoated at the edge regions. In this manner, edge regions of the blank can easily be provided which are necessary to join it to other blanks, for example to provide a “tailored blank”. All edge regions of the blank are preferably decoated using the method according to the invention, so that the blanks can be joined to a further blank at all edge regions by means of a welded seam.
[0017] Of course regions of the blank can also be decoated at least in part which are at least in part not localised in edge regions. This ensures that these regions can be joined to other sheet metals by means of welding, so that local strengthening can be arranged and so-called “patchwork blanks” can be provided. Furthermore, the at least in part decoated regions which for example are localised within a blank can also be used to join other components before and/or after forming, for example in vehicle body construction.
[0018] In accordance with a next embodiment of the method according to the invention, the decoating on both sides is carried out in one work step. To this end, a plurality of scraping knives are provided on both sides of the blanks which carry out a scraping of the region to be decoated substantially perpendicular to its main extension direction by means of the closing movement of the press. In this way, the decoating of blanks which are coated on both sides is made considerably easier. The decoating on both sides can advantageously be designed such that the decoating takes place on both sides of the blank simultaneously.
[0019] If a blank which is provided for hot forming is decoated at least in part, it can be welded to further blanks and/or parts without the welded seam tending to cause strength problems in the subsequent hot forming process.
[0020] In accordance with a next embodiment of the method according to the invention, a cut is made following the decoating at least in part of the blank, which is optionally carried out in the same work step in the press. The blanks, which have decoated regions after decoating, can be cut at said decoated regions so that in turn edge regions can be provided which are particularly suitable for welding. However, the cutting of the blank can also be carried out in the same press, and preferably in the same work step. This makes the manufacture of blanks which are suitable for welding significantly easier.
[0021] According to a further embodiment of the method according to the invention, for the decoating process the scraping knives are actively driven or forcibly actuated. Active driving of the scraping knives, for example by means of hydraulic or servo-electric means, enables maximum flexibility in terms of the point at which the decoating is carried out. However, the decoating is carried out in a particularly simple manner by forcibly actuated scraping knives which use the movements of the press to move the scraping knives, driven for example by means of a form lock, in order to decoat the blank in the desired region. Corresponding forcible actuating means have a particularly simple structure and are particularly process-reliable.
[0022] In accordance with a next embodiment of the method according to the invention, the regions of the blank which are to be decoated, in particular of a blank to be welded to other blanks in the edge joint, have a width of 0.2 mm to 5 mm, preferably a width of 0.8 mm to 1.4 mm. These widths are generally used to provide sufficient decoated blank material so that when generating a welded seam on these regions, in which laser beam welding is generally used, no undesirable coating components remain in the welded seam.
[0023] In accordance with a second teaching of the present invention, the above mentioned object of providing a device to carry out the method according to the invention is achieved in that the device comprises a press with an upper tool, a lower tool, a blank support, a pressing table, at least one scraping knife and means to move the at least one scraping knife substantially perpendicular to the main extension direction of the region of the blank to be decoated in order to decoat this region.
[0024] According to the invention, therefore, a press with an upper tool and a lower tool is used to decoat the blank using a scraping knife. In this way, the investment costs can be reduced, as the device according to the invention can be realized using existing systems. Furthermore, the movement of the scraping knife substantially perpendicular to the main extension direction of the region of the blank to be decoated enables a short cycle time and therefore a more economic decoating of the blank. Furthermore, the movement of the scraping knives can be provided by the closing movement of the press. Decoating of the blank in the regions provided for the welded seams is therefore carried out in a single working stroke and in this respect is particularly economical.
[0025] If the means for moving the at least one scraping knife comprise forcible actuation to guide a scraping knife or a plurality of scraping knives, simple means can be used to transform the closing movement of the press into a movement of the scraping knife, wherein the enormous forces provided by the press can be used at the same time. In comparison to actively driven scraping knives, for example servo-electrical or hydraulically driven scraping knives, a forcible actuation, which is generally carried out by means of a form lock, is particularly simple and process-reliable.
[0026] According to a further embodiment of the device according to the invention, at least one scraping knife in the upper tool and at least one scraping knife in the lower tool and scraping knife guides allocated to each scraping knife are provided, wherein the scraping knife guides of the upper tool are form locked to the scraping knife guides of the lower tool during the closing process of the press and the scraping knife guides of the lower tool are forcibly actuated by means of sleeves of the press which have thrust chamfers such that by means of a closing movement of the press the scraping knives in the upper tool and in the lower tool can be displaced perpendicular to the closing movement. This guarantees that decoating on both sides can also easily be carried out by means of forcibly actuated scraping knives on both sides of the blank.
[0027] If the press additionally has a cutting and/or punching stamp which cuts or punches the blank at least in part in the decoated regions, it is possible for the blank to be decoated in the regions thereof which are to be decoated and simultaneously to be cut in these regions in one working stroke, such that in one working stroke a blank which can be welded at the decoated regions can be provided.
[0028] In accordance with a further embodiment of the device according to the invention, a centrally-arranged compression stamp is provided in the upper and/or lower tool, which compression stamp compresses the blank onto the blank support during decoating. The use of this compression stamp ensures that the blank remains stationary during decoating. This means that the decoating can be designed in a process-reliable manner.
[0029] If the scraping knives provided in the upper and/or lower tool and the associated scraping knife guides form the blank support, wherein extensions are provided on the compression stamp and on the lower tool which extend through the scraping knife guides and have direct contact with the blank, in accordance with a further embodiment of the invention this enables the blank to be pressed firmly against the lower tool by means of the compression stamp and simultaneously the movement of the scraping knives to be decoupled from the forces exerted by the press on the blank. Furthermore, the use of the scraping knife guides at the same time as blank support enables that the scraping knives can also be used as cutting edges for the cutting and/or punching stamp, such that following to a successful scraping the stamp only has to be guided along the scraping knife or the scraping knife guides to cut the blank. As a result, a very clean cut of the blanks can also be achieved in the decoated region.
[0030] If in each case two opposing scraping knives are arranged on each side of the blank to be decoated, a blank can easily be decoated on both sides on two edge regions, in other words in four regions at once. This arrangement of the scraping knives reduces the amount of time required for decoating considerably, since this device enables decoating on four regions at the same time in one working stroke.
[0031] It is also conceivable that two blanks to be welded can be decoated in one tool on the four sides to be decoated simultaneously, for example in one working stroke or in one working stroke sequence, and in this way a decoated, weldable pair of blanks is created, wherein preferably the two blanks have different thicknesses.
BRIEF DESCRIPTION OF THE INVENTION
[0032] The invention shall be described in greater detail below using exemplary embodiments in combination with the figures, in which:
[0033] FIG. 1 is a schematic sectional view of a first exemplary embodiment of a device according to the invention for the decoating at least in part of a coated blankdecoat,
[0034] FIG. 2 is a detailed view of the scraping knife guide of the exemplary embodiment represented in FIG. 1 ,
[0035] FIG. 3 is a detailed view of the scraping knife and the blank of the exemplary embodiment represented in FIG. 1 ,
[0036] FIG. 4 is a schematic sectional view of the exemplary embodiment represented in FIG. 1 with the upper and lower tools closed,
[0037] FIG. 5 is a detailed view of the scraping knife guide represented in FIG. 4 ,
[0038] FIG. 6 is a detailed view of the scraping knife represented in FIG. 5 ,
[0039] FIG. 7 is a schematic sectional view of the exemplary embodiment represented in FIG. 1 following decoating of the blank,
[0040] FIG. 8 is a detailed view of the scraping knife guide represented in FIG. 7 ,
[0041] FIG. 9 is a detailed view of the scraping knife and the decoated region of the blank represented in FIG. 8 ,
[0042] FIG. 10 is a top view of a blank and the regions to be decoated,
[0043] FIG. 11 is a schematic sectional view of a second exemplary embodiment of a device according to the invention for decoating and cutting a blank when open,
[0044] FIG. 12 is the exemplary embodiment represented in FIG. 11 with the upper and lower tools closed,
[0045] FIG. 13 is a detailed view of the position of the scraping knife represented in FIG. 12 ,
[0046] FIG. 14 shows the exemplary embodiment represented in FIG. 11 after decoating and before cutting of the blank,
[0047] FIG. 15 is a detailed view of the scraping knife represented in FIG. 14 in the region of the decoated blank,
[0048] FIG. 16 shows the exemplary embodiment represented in FIG. 11 after cutting of the blank,
[0049] FIG. 17 is a detailed view of the cutting edges and the scraping knife guide of the exemplary embodiment represented in FIG. 11 and
[0050] FIG. 18 is a detailed view of the decoated blank immediately after cutting of the blank in the cutting region.
DETAILED DESCRIPTION OF THE INVENTION
[0051] FIG. 1 shows a first exemplary embodiment of a press 1 for decoating a blank 5 having an upper tool 2 , a lower tool 3 , a blank support 4 , a press stamp 6 a and a pressing table 6 b. The blank support 4 is arranged in the lower tool 3 . In the upper tool 2 , a counterholder 4 a is provided opposite the blank support 4 to impact the blank 5 with a retention force. Each two scraping knife guides 11 , 14 and 12 and 13 , which guide the scraping knives 7 , 8 , 9 and 10 , are arranged in pairs and mirror-symmetric to one another in the upper and lower tools 2 , 3 . The scraping knife guides 11 , 12 , 13 and 14 are impacted with a force by means of compression springs 20 such that the scraping knife guides press against the blank supports and are held in the scraping position.
[0052] FIG. 1 further shows sleeves 16 of press 1 which have thrust chamfers 15 at their ends which are used to forcibly actuate the scraping knife guides 11 , 14 . In order for the scraping knife guides 12 , 13 of the upper tool 2 to also be forcibly actuated synchronously to the scraping knife guides 11 , 14 of the lower tool 3 , said scraping knife guides have protruding regions 21 a which penetrate into recesses 21 b of the scraping knife guides 11 , 14 when the upper and lower tools 2 , 3 are closed. In this case, scraping knife guides 11 and 12 and 14 and 13 are form-locked to one another.
[0053] A detailed view of the scraping knife guide 14 and the scraping knife 10 and the blank 5 in the exemplary embodiment represented in FIG. 1 is shown in FIG. 2 . It should be noted that the blank 5 lies on the scraping knife 10 . This is better demonstrated in FIG. 3 . From this figure, it is possible to recognise that preferably curved scraping knives 10 are used in the exemplary embodiment shown. The width of the region to be decoated is approximately 1.2 mm in the present embodiment. In order to achieve a good result when decoating, it has been shown that it is advantageous if the scraping knife has a projection b of at least 0.04 mm.
[0054] FIG. 4 shows the exemplary embodiment from FIG. 1 schematically in a sectional view at the point at which the upper tool 2 is retracted into the lower tool 3 . The scraping knife guides 12 , 13 are then coupled to the scraping knife guides 11 and 14 in a form lock. The scraping knife guides 11 , 12 , 13 , 14 and therefore also the scraping knives 7 , 8 , 9 , 10 are held in position by the compression springs 20 such that no lateral movement of the scraping knives 7 , 8 , 9 , 10 occurs. The blank support 4 is pressed against the blank 5 by the pressure of the press stamp 6 a and the scraping knives are inserted into the coating of the blank to be decoated with their cutting edges. The position of the scraping knives 9 , 10 when the upper and lower tools 2 , 3 are closed is shown in FIG. 5 . In the exemplary embodiment shown, decoating on both sides can take place as the scraping knives 9 , 10 touch both the upper face and the lower face of the blank 5 . This is shown in an even clearer manner in FIG. 6 , which shows the region of the intrusion of the scraping knives 9 , 10 into the blank 5 to be decoated. When the upper and lower tools 2 , 3 are closed, the scraping knives, 9 , 10 penetrate the blank 5 , in particular the coating thereof.
[0055] The sleeves 16 are then moved out of the press or the pressing table 6 b is lowered relative to the sleeves. As a result, the sleeves 16 forcibly displace the scraping knife guides 11 , 14 of the lower tool outwards by means of their thrust chamfers 15 and the scraping knives 7 , 10 decoat the region of the blank to be decoated transverse to the main extension direction thereof. Due to the form lock between the scraping knife guides 11 , 14 of the lower tool 3 and the scraping knife guides 12 , 13 of the upper tool 2 , the movement of the scraping knife guides 12 , 13 and therefore the scraping knives 8 , 9 is identical. These scraping knives are also forcibly displaced outwards resulting in a decoating of the blank by a movement of a scraping knife 8 , 9 substantially perpendicular to the main extension direction of the region to be decoated.
[0056] In FIG. 7 , the decoating process is already complete as the sleeves are fully inserted into a recess of the scraping knife guides 11 , 12 and the thrust chamfers 15 are completely worn down by the scraping knife guides 11 , 14 .
[0057] FIG. 8 is a detailed view of the position of the scraping knives 9 , 10 after completion of the decoating process according to FIG. 7 . It should be noted that the scraping knives 9 , 10 have already released the blank. FIG. 9 is a detailed view of the decoated region of the blank 5 . The blank 5 is decoated on both sides in this region.
[0058] However, it is also conceivable for the scraping knives to be used on just one side of the blank. However, the blanks are generally welded on their edges, so decoating of the edges on both sides is often necessary.
[0059] FIG. 10 is a top view of a blank 22 . The blank has a circumferential region 22 a to be decoated which has been decoated using a device according to the invention. The directions of the arrows show the direction of movement of the scraping knives which have been used to decoat the blank 22 . It can easily be conceived that with a movement which is so short (a few millimetres) the scraping process or the decoating process occurs correspondingly rapidly and therefore can lead to very low cycle times.
[0060] FIG. 11 now shows a second exemplary embodiment of a device for decoating a blank comprising a press 1 which has a press stamp 6 a and a pressing table 6 b. The scraping knife guides 11 , 12 , 13 14 of the exemplary embodiment represented in FIG. 11 now simultaneously form the blank support and are each held in pairs at the decoating position or initial position by means of tension springs. Furthermore, the exemplary embodiment represented in FIG. 11 also has an end stop position block 24 and a scrap chute 25 . The scrap chute 25 serves to guide away the cutting remnants which occur during cutting of the blank 5 in a controlled manner. The end position block 24 delimits the path of the press stamp 6 a.
[0061] In the lower tool 3 of the second embodiment, sleeves 16 are further provided which have thrust chamfers or thrust wedges 15 which are used to forcibly actuate the scraping knife guides 11 , 14 . In contrast to the exemplary embodiment represented in FIG. 1 , the second exemplary embodiment of the device according to the invention also has thrust chamfers or thrust wedges 15 in the upper tool 2 . A compression stamp 18 is further provided, which has direct contact with the blank by means of extensions 19 leading through the scraping knife guides 12 , 13 which are not shown in FIG. 11 . Identical to these extensions 19 in the upper tool 2 , extensions 19 are also provided in the lower tool 3 which transfer the pressure of the compression stamp 18 exerted by the upper tool 2 on the blank to the lower tool 3 . The extensions 19 of the lower tool 3 are also not shown in FIG. 11 .
[0062] FIG. 12 shows the second exemplary embodiment at the point at which the upper and lower tools 2 , 3 are closed and the scraping knives 7 , 8 , 9 , 10 engage with the blank 5 . In this position, the tension springs 23 hold the scraping knife guides 11 , 12 , 13 , 14 together at the initial position. The compression stamp 18 transfers a force onto the blank 5 by means of the extensions 19 , which force is passed on to the extensions 19 of the lower tool 3 .
[0063] This means that the full load of the scraping knives 11 , 12 , 13 , 14 does not lie on the blank 5 and can easily be moved laterally. The thrust chamfers 15 can clearly be seen in FIG. 12 , which thrust chamfers are arranged in both the lower tool and the upper tool. At this point, the cutting stamp 17 is still in the initial position and is not engaged with the blank 5 .
[0064] FIG. 13 is a detailed view of the scraping knife guides 11 , 12 including their scraping knives 7 , 8 . When the upper and lower tools 2 , 3 are closed, the scraping knives 7 , 8 penetrate the coating of the blank 5 .
[0065] If the press stamp 6 a continues to move closer, the scraping knife guides 11 , 12 , 13 , 14 are displaced outwards by means of the thrust chamfers 15 or thrust wedges 15 against the tensile force of the springs 23 and carry out the scraping process. The scrapping knives decoat the blank 5 in a region which has a main extension. The movement of the scraping knives is generally perpendicular to the main extension direction of the region of the blank 5 to be decoated.
[0066] The cutting stamp 17 reaches the cutting position, FIG. 14 , after the completion of the decoating. FIG. 15 , which is a detailed view of a decoated region of the blank 5 from FIG. 14 , clearly shows the start of the cutting process. After completion of the decoating process, the blank has decoated regions 5 a. The thrust chamfers have been passed through by the scraping knife guides 11 , 12 , 13 , 14 , such that where there is further lowering of the press stamp 6 a there is no further lateral movement of the scraping knife guides 11 , 12 , 13 , 14 . Only the cutting knife 17 is moved downwards, such that the scraping knife functions as a cutting edge for the cutting or punching stamp 17 at the same time.
[0067] FIG. 16 shows the press moved to the end position. The cutting stamp 17 has now cut both sides of the blank 5 and the cutting remnants 26 are moved out of the work area in a controlled manner via the scrap chute 25 .
[0068] FIG. 17 is a detailed view of the cut region. As can be seen, the thrust chamfers 15 play no further role in the movement of the cutting stamp 17 . With the device according to the invention and with the method according to the invention, a blank can easily be provided, the edges of which are decoated and cut in one work step. The above mentioned AlSi coatings are available for the coating. However, it is also conceivable for other coatings to be removed from a blank.
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The invention relates to a method for the decoating at least in part of blanks made of metal which are coated on one or both sides in regions, which have a main extension direction, wherein the regions to be decoated can extend in both a straight or curved manner in the main extension direction. The invention further relates to a device for the decoating at least in part of a coated blank in order to carry out the method according to the invention. A method is provided in which the blank is placed on a blank support of a press and during the closing movement of the press at least one scraping knife preferably completely removes the coating of the blank by scraping substantially perpendicular to the main extension direction of the region of the blank to be decoated.
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This application claims the benefit of U.S. Provisional Application No. 60/554,213 filed on Mar. 18, 2004, which is herein incorporated by reference.
The present invention relates generally to traffic monitoring and, more particularly, to a method and apparatus for rapid location of anomalies in traffic logs for networks, e.g., packet communication networks such as VoIP networks.
BACKGROUND OF THE INVENTION
The Internet has emerged as a critical communication infrastructure, carrying traffic for a wide range of important scientific, business and consumer applications. Network service providers and enterprise network operators need the ability to detect anomalous events in the network, for network management and monitoring, reliability, security and performance reasons. While some traffic anomalies are relatively benign and tolerable, others can be symptomatic of potentially serious problems such as performance bottlenecks due to flash crowds, network element failures, malicious activities such as denial of service attacks (DoS), and worm propagation. It is therefore very important to be able to detect traffic anomalies accurately and in near real-time, to enable timely initiation of appropriate mitigation steps.
One of the main challenges of detecting anomalies is the mere volume of traffic and measured statistics. This is a particular challenge where the system architecture does not leverage such methods as built-in bottlenecks for failsafe enforcement of policy controls. Given today's traffic volume and link speeds, the input data stream can easily contain millions or more of concurrent flows, so it is often impossible or too expensive to maintain per-flow state. The diversity of network types further compounds the problem. Thus, it is infeasible to keep track of all the traffic components and inspect each packet individually for anomalous behavior. Further risks include the difficulty in discerning whether a usage pattern constitutes the unauthorized access, control or modification of information or system resources. Host-based and network-based logging provides a potential recognition basis as well as the forensic capability to ensure a level of accountability for action or inaction.
Another challenge is that different types of anomalies manifest themselves in a variety of ways and remain in the network for different durations. The anomalies with large durations are identified by detection methods such as top ten counting. The anomalies that are a major challenge to detect are those appearing repeatedly for short durations. Another challenge is the unauthorized tunneling or copying of information, or example by malfeasant information gathering, illicit proxy or store/forward, hijacked management capabilities or outright spyware.
Therefore, a need exists for a method and apparatus for near real-time detection of anomalies in traffic logs that elude simple ranking methods such as “top ten” counting. Anomaly detection is critical for monitoring and maintaining packet networks, e.g., Voice over Internet Protocol (VoIP) networks.
SUMMARY OF THE INVENTION
In one embodiment, the present invention discloses a method and apparatus for rapidly detecting anomalies that elude methods such as top ten counting from massive data streams with a large number of flows. In one embodiment, the method determines the conditions for greater position in the ranking and closer scrutiny. The method then applies the conditions and determines the number of entrances of an entity being observed to the list, number of events while on the list and duration on the list for each observed entity, such as an IP address. Anomalies are detected by comparing with historical data and data collected for other similar entities and profiles. For example, comparisons can be made among IP addresses that share a DNS server.
Thus, the present invention provides an efficient method for computing the highest ranked items in real time and identifying anomalies. The accurate selection of addresses that require further analysis reduces the cost of monitoring, the cost of managing the security of the network as well as reduces the time needed to initiate mitigation steps.
BRIEF DESCRIPTION OF THE DRAWINGS
The teaching of the present invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings, in which:
FIG. 1 illustrates an exemplary network related to the present invention;
FIG. 2 illustrates a flowchart of a method for rapid location of anomalies in traffic logs; and
FIG. 3 illustrates a high level block diagram of a general purpose computer suitable for use in performing the functions described herein.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures.
DETAILED DESCRIPTION
The present invention broadly discloses a method and apparatus for rapidly detecting anomalies in network traffic logs. Although the present invention is discussed below in the context of detecting traffic anomalies in a network, the present invention is not so limited. Namely, the present invention can be applied in the context of outlier detection in a data stream, flu outbreaks etc. Furthermore, although the present invention is discussed below in the context of packets, the present invention is not so limited. Namely, the present invention can be applied in the context of records, fields, or any other unit or measure of data. For the purpose of scope, the term packet is intended to broadly include a record or a field.
To better understand the present invention, FIG. 1 illustrates an example network, e.g., a packet network such as a VoIP network related to the present invention. Exemplary packet networks include internet protocol (IP) networks, asynchronous transfer mode (ATM) networks, frame-relay networks, and the like. An IP network is broadly defined as a network that uses Internet Protocol to exchange data packets. Thus, a VoIP network or a SoIP (Service over Internet Protocol) network is considered an IP network.
In one embodiment, the VoIP network may comprise various types of customer endpoint devices connected via various types of access networks to a carrier (a service provider) VoIP core infrastructure over an Internet Protocol/Multi-Protocol Label Switching (IP/MPLS) based core backbone network. Broadly defined, a VoIP network is a network that is capable of carrying voice signals as packetized data over an IP network. The present invention is described below in the context of an illustrative VoIP network. Thus, the present invention should not be interpreted to be limited by this particular illustrative architecture.
The customer endpoint devices can be either Time Division Multiplexing (TDM) based or IP based. TDM based customer endpoint devices 122 , 123 , 134 , and 135 typically comprise of TDM phones or Private Branch Exchange (PBX). IP based customer endpoint devices 144 and 145 typically comprise IP phones or PBX. The Terminal Adaptors (TA) 132 and 133 are used to provide necessary interworking functions between TDM customer endpoint devices, such as analog phones, and packet based access network technologies, such as Digital Subscriber Loop (DSL) or Cable broadband access networks. TDM based customer endpoint devices access VoIP services by using either a Public Switched Telephone Network (PSTN) 120 , 121 or a broadband access network via a TA 132 or 133 . IP based customer endpoint devices access VoIP services by using a Local Area Network (LAN) 140 and 141 with a VoIP gateway or router 142 and 143 , respectively.
The access networks can be either TDM or packet based. A TDM PSTN 120 or 121 is used to support TDM customer endpoint devices connected via traditional phone lines. A packet based access network, such as Frame Relay, ATM, Ethernet or IP, is used to support IP based customer endpoint devices via a customer LAN, e.g., 140 with a VoIP gateway and router 142 . A packet based access network 130 or 131 , such as DSL or Cable, when used together with a TA 132 or 133 , is used to support TDM based customer endpoint devices.
The core VoIP infrastructure comprises of several key VoIP components, such the Border Element (BE) 112 and 113 , the Call Control Element (CCE) 111 , and VoIP related servers 114 . The BE resides at the edge of the VoIP core infrastructure and interfaces with customers endpoints over various types of access networks. A BE is typically implemented as a Media Gateway and performs signaling, media control, security, and call admission control and related functions. The CCE resides within the VoIP infrastructure and is connected to the BEs using the Session Initiation Protocol (SIP) over the underlying IP based core backbone network 110 . The CCE is typically implemented as a Media Gateway Controller and performs network wide call control related functions as well as interacts with the appropriate VoIP service related servers when necessary. The CCE functions as a SIP back-to-back user agent and is a signaling endpoint for all call legs between all BEs and the CCE. The CCE may need to interact with various VoIP related servers in order to complete a call that requires certain service specific features, e.g. translation of an E.164 voice network address into an IP address.
For calls that originate or terminate in a different carrier, they can be handled through the PSTN 120 and 121 or the Partner IP Carrier 160 interconnections. For originating or terminating TDM calls, they can be handled via existing PSTN interconnections to the other carrier. For originating or terminating VoIP calls, they can be handled via the Partner IP carrier interface 160 to the other carrier.
Note that a customer in location A using any endpoint device type with its associated access network type can communicate with another customer in location Z using any endpoint device type with its associated network type as well. The BEs 112 and 113 are responsible for the necessary signaling protocol translation and media format conversion, such as TDM voice format to and from IP based packet voice format.
The above VoIP network is described to provide an illustrative environment in which a large quantity of packets may traverse throughout the entire network. It would be advantageous to be able to detect anomalies in the network rapidly in order to monitor performance bottleneck, reliability, security, malicious attacks and the like. It is necessary to detect both the short and long duration anomalies events. The present invention provides a method for detecting anomalies that elude methods such as “top ten” counting. In one embodiment, the present method as discussed below can be implemented in an application server of the packet network, e.g., a VoIP network.
In order to clearly illustrate the present invention, the following description assumes a packet network. Without loss of generality, these concepts may be applicable to Uniform Resource Identifiers (URI) and the protocol-specific Uniform Resource Locations (URLs). The URL in particular describes both the packet address as well as the upper-level content-description of the service or resource. The packet network related concepts are that of aggregate descriptions about the resources:
Number of unique addresses (i.e., the degree); Count of addresses; Event; Siblings; and Cousins.
Number of unique values for a protocol element such as a DNS-name, dialed number, plurality of MPLS labels, destination or a source IP address. The degree is the number of distinct endpoints per event. For example, if a server with an IP address sends a multicast packet to a large list of servers, the degree of addresses refers to the number of IP addresses or servers to which the packet was addressed. The effective degree is the number of IP addresses or servers receiving that same message. The referred degree is the number of indirect recipients, for example due to possibly unauthorized forwarding agents.
Accumulated and recent totals for protocol-defined attributes and values. The count of addresses for an element such as an IP address is the total number of packets (or packet size) per event. For example, if a server sends a 100 kb message to each of ten IP addresses, the exact number of packets depend on configurations and network conditions; the total of packet sizes is 1 Mb. However, if a server updates several other servers, and those servers each send a 100 kb message to ten IP addresses, the indirect yet causal attribution is many megabytes. The unique attribution of delegated traffic is difficult in the absence of explicit traffic tags.
Accumulated totals on delegated traffic occurrences, represented as the values and frequencies of non-routable message digest functions for IP packet elements that pass unaltered through networking infrastructure. These impose equivalence classes on traffic by means of the unique digest value, yet traffic integrity policies are unaffected by inherently opaque digests. Both cryptographic hashes (MD5) and more compact representations are examples of such digest functions. The occurrence of repeated digest values supports unique attribution of delegated traffic.
An event is broadly defined as a trackable or monitored behavior. For example, an event may include but is not limited to, accessing a web site, downloading a software application, downloading an image sequence, contracting a disease, and the like. An observation of an event is the detection of an occurrence of the event. Furthermore, one can define one or more conditions associated with an event (known as policy-defined or condition-defined data), e.g., downloading the same movie four times in one day.
Siblings are IP addresses that share a network property such as domain-name or DNS server and they are referred to as siblings through that domain-name or server.
Cousins are IPn sibling sets that share elements through an ancestor. The number of shared elements in two siblings' reference sets gives a similarity metric. For example, two sibling sets that share the first 6 digits of the IP address are more similar than those that share only the first 3 digits.
In one embodiment, the present method ranks two component elements such as source and destination IP addresses by the cumulative residency within rolling histories. The top ranks are continuously updated according to the degree and count of addresses. The number of distinct endpoints and the total packets for each event determine which IP addresses belong on the list as well as relative positions on the list.
Once the rankings of the different addresses are determined, comparisons are made with the siblings and cousins to identify unusual patterns. The ranking is also compared with historical data or condition-defined data.
As noted above, the Internet is a critical communication infrastructure, carrying traffic for a wide range of important scientific, business and consumer applications. Network service providers and enterprise network operators need the ability to detect anomalous events in the network, for network management and monitoring, reliability, security and performance reasons. While some traffic anomalies are relatively benign and tolerable, others can be symptomatic of potentially serious problems such as performance bottlenecks due to flash crowds, network element failures, malicious activities such as denial of service attacks (DoS), and worm propagation. It is therefore very important to be able to detect traffic anomalies accurately and in near real-time, to enable timely initiation of appropriate mitigation steps.
The major challenges for detection of anomalies are the volume of traffic and the variety of the behavior. The anomalies manifest themselves in a variety of ways and remain in the network for different durations. The anomalies with large durations are identified by detection methods such as top ten counting. The anomalies that are a major challenge to detect are those appearing repeatedly for short durations. The current invention detects such bursty behaviors as suspicious or as activities of interest. Once the list of IP addresses that deserve further analysis (or the candidates) are identified, the traffic is further analyzed for abnormal behavior.
In one embodiment, the present method ranks two component elements such as source and destination IP addresses by the cumulative residency within rolling histories. The ranks are updated according to the degree and count of the addresses. The criteria to be on the list depend on the application. The observations have similar format. Some examples include but are not limited to, entering certain web sites, driving the network load by a predetermined percentage point, high frequency of observation events for a time period etc. The degree and count are maintained for all addresses on a per event basis.
The data is aggregated over multiple historical sizes selected for the application. For example, rolling 30, 60, 600 and 3600 second data history logs are useful for IP traffic. The rankings are both source-to-destination and destination-to-source. Hence, an IP address can be ranked higher for either receiving requests or sending requests. The ranking is maintained on a continual basis. Note that the rank can change up or down with each observation that enters the history or departs after the lifetime expires.
Table 1 illustrates a ranking list for source (SRC) and destination (DST) IP addresses of packets by the cumulative residency within rolling histories.
TABLE 1
Number of
Number
Number of
Events
Number of
(Ranking
times
during
Seconds
Address
Position)
entered
residency
resident in
(Fictitious IP
in Top 10
the Top
in Top 10
Top 10
Type
addresses)
List
Ten List
List
List
SRC
XY_77_252_226
3
303
161986
65895
DST
PQ_20_20_20
2
2
213970
86384
DST
RST_255_255_255
2
2
213944
86375
DST
XY_77_20_255
2
1
213849
86329
DST
XY_77_92_96
2
2
213546
86222
DST
XY_77_201_268
2
5
212447
85770
SRC
XY_77_20_54
2
47
205016
82927
DST
XY_77_20_30
2
62
200660
81282
SRC
XY_77_202_82
2
15
187305
75479
DST
XY_77_20_0
2
90
184994
74701
DST
XY_77_20_7
1
177
147173
60793
SRC
XY_77_92_119
1
330
144142
58944
SRC
XY_77_92_98
1
407
82102
33657
SRC
XY_77_204_222
1
398
45949
18501
DST
XY_77_2_0
1
390
9254
3864
DST
XY_77_20_115
1
349
5193
2155
SRC
XY_77_20_2
1
275
2635
1132
DST
XY_277_296_222
1
189
1539
732
The first column indicates the functional role of whether the element was a destination or a source for the packet. SRC represents source addresses and DST represents destination addresses.
The second column represents an entity or object (not necessarily an identifiable principal) and typically includes the IP addresses. Letters are used in the first part of the addresses to make sure that the addresses do not represent any real IP address. The addresses are fictitious and are shown for the purpose of illustrating the present invention. Generally, the first part of such IP addresses are assigned through a DNS authority and are represented by numbers instead of letters.
The third column provides the ranking position on the list. The highest number of observations is ranked number 1. It is assumed that the addresses are ranked in a rank list having a number of ranked positions, e.g., a list of top 10. However, it should be noted that the list can have any number of rankings including median or percentiles in accordance with the requirement of a particular implementation. Illustratively, the present example has only addresses that are ranked 1 st , 2 nd or 3 rd as shown in Table 1.
The fourth column indicates the number of times the particular IP address entered the top ten list. For example, if traffic volume is the behavior being observed, an IP address with changed burst frequencies due to bursty traffic at abnormal intervals would enter and exit the top ten list more often than an IP address with consistently high volume of well-categorized traffic. Hence, column 4 is instrumental in identifying the addresses with bursty patterns. The mere fact that network traffic is bursty does not imply that it is a suspect. The data needs to be compared to historical values (which may be retained through adaptive filters in the network infrastructure) and to comparable data collected for the sibling and cousin IP addresses. For example, a large increase in traffic volume from a financial institution every week-night might simply imply data storage or data synchronization with a remote site. Thus, the IP address for the financial institution might be on the top ten list one time in every 24 hour period. It is considered anomalous upon departure from the acceptable variations from the patterns of occurrence, such as if suddenly it is on the rank list several times in the same time interval.
The fifth column indicates the number of events that are observed while on the top 10 list and the sixth column indicates the length of time in seconds the address is on the top 10 list.
Methods such as “top ten” counting may identify the high-ranking addresses. However, none of those methods attempt to determine the rate at which addresses move in and out of the ranking and their movement within the ranking. The present invention uses the rate of movement within the list and the manner of movement (e.g., in and out) of the rank list to identify anomalies of bursty nature.
In one embodiment, the present method allows observations to expire. This is because stale entries need to be deleted from the list. In addition, if the number of entries to be analyzed is smaller, the analysis and comparison of data can be performed quicker. This allows the network manager to initiate mitigation steps quicker as well as to adjust load for legitimate changes.
Note that the present invention also identifies the anomalies of longer duration. Greater rank is given to an address that frequently has many endpoints compared to an address that has more connections but usually has fewer endpoints. For example, in network security applications it is important to identify viruses and take mitigation steps quickly. If a large node is sending infected emails to large number of customers at a time, the virus will impact computers more quickly compared to infected email sent to few computers at a time even if the action is repeated. The initial impact is greater for the connections with many endpoints. The remedy can be initiated quicker if such connections have greater ranking.
The present method ranks addresses by the cumulative residency within rolling histories in real time. The rank is always being updated according to the parameters such as total packets per event, the number of distinct endpoints per event etc. The data is aggregated over several time intervals of interest for comparison with both historical and sibling data. As opposed to other top ranking methods, the current method detects anomalies quickly and can be applied for streaming data. Anomalies need to be detected as they occur as opposed to minutes later. Mathematically, it is analogous to utilizing the derivative (rate of change) as opposed to tracking the actual value.
For the example in Table 1, it is important to identify or flag the addresses that are moving from the 10 th place to the 2 nd place more often, as opposed to the addresses that are moving from the 10 th place to the 9 th place. Movements of more than one position are rare in typical IP traffic. Such movement warrants a closer analysis specially if it is repeated often. Furthermore, comparisons with siblings and cousins may reveal if there is a general change of pattern.
If a change of pattern is recognized and found to be legitimate, the servers or network managers can redistribute the load so that the address won't show up on anomaly or interesting data list. An anomaly is broadly defined to be an event of interest, e.g., such as performance bottlenecks due to flash crowds, network element failures, malicious activities such as denial of service attacks (DoS), and worm propagation, and the like. Although the present invention is described in the context of a network, the present invention is not so limited. In other field of uses, an anomaly may be an epidemic, a financial condition, and the like.
FIG. 2 illustrates a flowchart of a method 200 for rapid detection of anomalies in network traffic logs of the present invention. Method 200 starts in step 205 and proceeds to step 210 .
In step 210 , method 200 establishes the conditions for an event. For example, a condition for an event can be driving network load by more than a predetermined percentage point. The frequency and the quantity of the condition to be observed are studied prior to setting the threshold, and may follow a predictive model within a statistically controlled variation. Otherwise, either too many events will be detected or not all the events that should be on the list will be detected. The condition is adjusted when the network behavior changes. For example, releases of new applications such as movies on demand by service providers are expected to increase the volume of large packet transmissions. The relevance of a change may depend on the service architecture, and should balance the service-requirements with potential impact to other services. An increase of 1% after a major movie release may not be relevant unless it is to a high-value resource (login server) with concomitant risk, or it violates network consistency characteristics (contacting IP addresses outside of the name resolution patterns of the DNS server), or the traffic replicates artifacts, which would be unknown to the legitimate customer.
In step 220 , method 200 collects the time stamped events. For each event, both the degree and count are collected. For the server example, the number of endpoints and the total number (size) of packets are collected for each event.
In step 230 , method 200 builds the aggregates. For example, establishing objects, groups and comparison with previous aggregates are performed in this step. For example, objects can be individual source or destination IP addresses, pairs of source and destination IP addresses, pairs of ports etc. Composite objects are objects that contain a number of related IP addresses. An example is an object containing a DNS server and all its clients. After the objects are established, the groups are determined. In other words, the number of unique endpoints and the size of traffic for each endpoint are determined. Comparisons can be made to determine the differences with the previous aggregates and identify the new aggregates.
In step 240 , method 200 builds the multiple historical sizes for each of the objects. For example, history sizes of 30, 60, 600 and 3600 seconds can be maintained for each IP address or pairs of IP addresses identified in step 230 .
In step 250 , method 200 updates the ranking for the monitored objects and proceeds to step 260 .
In step 260 , method 200 provides a summary description of the list. The information will be used for subsequent deletions. The deletion occurs when the data is stale (no longer relevant), has not been referred or smaller number of entries are desired for the analysis.
In step 270 , method 200 monitors the ranking list. If the data is not relevant, the method shrinks the aggregate description derived in step 230 and updates the ranking. If the data is still relevant or new, it will remain on the list. The monitoring includes movement of the objects within the rank list as well as the entry to and the exit from the rank list. As illustrated in Table 1, the movements of the objects (e.g., in and out) in the list are reported. The movement data is critical for detection of bursty anomalies behavior.
In step 275 , method 200 compares the monitored statistics with the profile. Comparisons are made with historical data as well as data collected for siblings and cousins. For example, the profiles of IP addresses that share a DNS server would be similar.
In step 280 , method 200 determines whether an anomalies behavior is detected or not. If no anomaly exists, the method proceeds to step 220 to collect more time stamped data. If anomaly is detected, the method proceeds to step 285 . Specific examples of anomalies are given above, e.g., the occurrence of repeated digest values supports unique attribution of delegated traffic, whereas the occurrence of these same values on other network segments cannot be attributed to “chance”, the traffic replicates artifacts which would be unknown to the legitimate customer, and so on.
In step 285 , method 200 determines the appropriate action. For example, if the behavior is legitimate, resources may be reallocated. If the behavior is not legitimate, the anomaly is reported so that mitigation steps (e.g., interrupting an event, e.g., instructing a router to refuse or shunt service from an endpoint device with a particular source IP address, shutting down a server, and the like) can be initiated or the object is reported (e.g., generating a warning flag) so that greater scrutiny is applied to the object.
It is important to note that once the network is able to determine the portion of the data deserving of further analysis, the network is better equipped to more accurately and efficiently detect anomalous events. Method 200 may proceed to perform other post analysis functions such as reporting to customers, billing etc. Method 200 ends in step 290 .
It should be noted that the steps of method 200 of FIG. 2 need not be performed for each event or is required to be performed in the order as shown. In fact, some of the steps can be treated as optional depending on the requirements of a particular implementation.
FIG. 3 depicts a high level block diagram of a general purpose computer suitable for use in performing the functions described herein. As depicted in FIG. 3 , the system 300 comprises a processor element 302 (e.g., a CPU), a memory 304 , e.g., random access memory (RAM) and/or read only memory (ROM), an anomaly detection module 305 , and various input/output devices 306 (e.g., storage devices, including but not limited to, a tape drive, a floppy drive, a hard disk drive or a compact disk drive, a receiver, a transmitter, a speaker, a display, a speech synthesizer, an output port, and a user input device (such as a keyboard, a keypad, a mouse, and the like)).
It should be noted that the present invention can be implemented in software and/or in a combination of software and hardware, e.g., using application specific integrated circuits (ASIC), a general purpose computer or any other hardware equivalents. In one embodiment, the present anomaly detection module or process 305 can be loaded into memory 304 and executed by processor 302 to implement the functions as discussed above. As such, the present anomaly detection method 305 (including associated data structures) of the present invention can be stored on a computer readable medium or carrier, e.g., RAM memory, magnetic or optical drive or diskette and the like.
While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
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An efficient method and apparatus for rapidly detecting anomalies from massive data streams is disclosed. In one embodiment, the method enables near real time detection of anomaly behavior in networks. The invention rapidly identifies the addresses that require further analysis and reduces the cost of monitoring, the cost of managing the security of the network as well as reduces the time needed to initiate mitigation steps.
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TECHNICAL FIELD
This invention relates to memory devices, and, more particularly, to a method and system for efficiently checking and correcting data read from memory devices to allow the memory devices to consume relatively little power during refresh.
BACKGROUND OF THE INVENTION
As the use of electronic devices, such as personal computers, continues to increase, it is becoming ever more important to make such devices portable. The usefulness of portable electronic devices, such as notebook computers, is limited by the limited length of time batteries are capable of powering the device before needing to be recharged. This problem has been addressed by attempts to increase battery life and attempts to reduce the rate at which such electronic devices consume power.
Various techniques have been used to reduce power consumption in electronic devices, the nature of which often depends upon the type of power consuming electronic circuits that are in the device. For example, electronic devices such as notebook computers, typically include memory devices, such as dynamic random access memory (“DRAM”) devices, that consume a substantial amount of power. As the data storage capacity and operating speeds of memory devices continue to increase, the power consumed by such devices has continued to increase in a corresponding manner. Therefore, many attempts to reduce the power consumed by an electronic device have focused on reducing the power consumption of memory devices.
In general, the power consumed by a memory device increases with both the capacity and the operating speed of the memory device. The power consumed by memory devices is also affected by their operating mode. For example, a DRAM device generally consumes a relatively large amount of power when the memory cells of the DRAM device are being refreshed. As is well-known in the art, DRAM memory cells, each of which essentially consists of a capacitor, must be periodically refreshed to retain data stored in the DRAM device. Refresh is typically performed by essentially reading data bits from the memory cells in each row of a memory cell array and then writing those same data bits back to the same cells in the row. A relatively large amount of power is consumed when refreshing a DRAM because rows of memory cells in a memory cell array are being actuated in the rapid sequence. Each time a row of memory cells is actuated, a pair of digit lines for each memory cell are switched to complementary voltages and then equilibrated. As a result, DRAM refreshes tend to be particularly power-hungry operations. Further, since refreshing memory cells must be accomplished even when the DRAM is not being used and is thus inactive, the amount of power consumed by refresh is a critical determinant of the amount of power consumed by the DRAM over an extended period. Thus many attempts to reduce power consumption in DRAM devices have focused on reducing the rate at which power is consumed during refresh.
Refresh power can, of course, be reduced by reducing the rate at which the memory cells in a DRAM are being refreshed. However, reducing the refresh rate increases the risk that data stored in the DRAM memory cells will be lost. More specifically, since, as mentioned above, DRAM memory cells are essentially capacitors, charge inherently leaks from the memory cell capacitors, which can change the value of a data bit stored in the memory cell over time. However, current leaks from capacitors at varying rates. Some capacitors are essentially short-circuited and are thus incapable of storing charge indicative of a data bit. These defective memory cells can be detected during production testing, and can then be repaired by substituting non-defective memory cells using conventional redundancy circuitry. On the other hand, current leaks from most DRAM memory cells at much slower rates that span a wide range. A DRAM refresh rate is chosen to ensure that all but a few memory cells can store data bits without data loss. This refresh rate is typically once every 64 ms. The memory cells that cannot reliably retain data bits at this refresh rate are detected during production testing and replaced by redundant memory cells.
One technique that has been used to prevent data errors during refresh as well as at other times is to generate an error correcting code “ECC,” which is known as a “syndrome,” from each item of stored data, and then store the syndrome along with the data. When the data are read from the memory device, the syndrome is also read, and it is then used to determine if any bits of the data are in error. As long as not too many data bits are in error, the syndrome may also be used to correct the read data.
The use of ECC techniques can allow DRAM devices to be refreshed at a slower refresh rate since resulting data bit errors can be corrected as long as the refresh rate is not so low that more errors are generated than can be corrected by ECC techniques. The use of a slower refresh rate can provide the significant advantage of reducing the power consumed by DRAM devices. Prior to entering a reduced power refresh mode, each item of data is read. A syndrome corresponding to the read data is then generated and stored in the DRAM device. When exiting the reduced power refresh mode, the each item of data and each corresponding syndrome are read from the DRAM device. The read syndrome is then used to determine if the item of read data is in error. If the item of read data is found to be in error, the read syndrome is used to correct the read item of data, and the incorrect item of data is then overwritten with the corrected item of data.
One disadvantage of using the above-described ECC techniques in memory systems is the time and power required to generate and store ECC syndromes when entering the reduced power refresh mode. Each time the reduced power refresh mode is entered, all of the data stored in the DRAM device must be read, and a syndrome must be generated for each item or group of items of read data. The generated syndromes must then be stored. It can require a substantial period of time to accomplish these operations for the large amount of data stored in conventional high-capacity DRAM devices. During this time that the stored data are being checked, the DRAM device generally cannot be accessed for a read or a write operation. As a result, the operation of memory access devices, such as processors, is stalled until the data checking operations have been completed. Furthermore, a substantial amount of power can be consumed during the time the stored data are being checked and possibly corrected. These operations must be performed even though very little if any of the data stored in the DRAM device may have changed since the data was previously read and corresponding syndromes stored.
A similar problem exists where ECC techniques are being used to correct data storage errors in normal operation, i.e., not for a reduced power refresh mode. Each time a read request is coupled to a DRAM or other memory device, the syndrome corresponding to the read data must also be read, and the read data must then be checked using the read syndrome. These operations must be performed each time a read request is received even though the read data may not have changed since the read data was either written or previously read. The time required to perform these operations increases the latency of the memory device since the read data are not accessible to a memory requester until after these operations have been completed.
There is therefore a need for a memory system and method that uses ECC techniques to insure data integrity and allow operations in a reduced power refresh mode, but does so in a manner that does not unduly increase the read latency or power consumption of the memory device.
SUMMARY OF THE INVENTION
An error checking and correction (“ECC”) method and system includes an ECC syndrome and a respective flag bit stored for each of a plurality of groups of data bits stored in an array of memory cells. The flag bit has a first value when the ECC syndrome is stored, and a second value if any of the data bits in the respective group are modified such as by writing data to the memory cells storing the data bits. The ECC method and system may be used in a reduced power refresh mode by checking the flag bit corresponding to each group of data bits and then generating and storing a new syndrome if the flag bit has the second value indicative of at least some of the data bits in a group were modified since the previous refresh. The ECC method and system may also be used during refresh or in normal operation to determine if an ECC syndrome can be used to check and correct corresponding data. When used in this manner, the ECC syndrome is used to check the correctness of the data bits, and, if an error is found, to generate corrected data bits. The corrected data bits can then be stored in the memory device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a computer system according to one of the invention.
FIG. 2 is a flow chart showing the operation of the memory device of FIG. 1 in a low power refresh mode.
FIG. 3 is a flow chart showing the operation of the memory device of FIG. 1 in checking the integrity of data stored in the memory device.
FIG. 4 is a block diagram of a memory device according to one embodiment of the invention that may be used in the computer system of FIG. 1 .
FIG. 5 is an address map showing the organization of data stored in the memory device of FIG. 1 or FIG. 4 according to one embodiment of the invention.
FIG. 6 is an address map showing the organization of data stored in the memory device of FIG. 1 or FIG. 4 according to another embodiment of the invention.
DETAILED DESCRIPTION
A computer system 100 including a memory device employing ECC techniques according to one embodiment of the invention is shown in FIG. 1 . The computer system 100 includes a central processor unit (“CPU”) 104 coupled to a system controller 106 through a processor bus 108 . The system controller 106 is coupled to input/output (“I/O”) devices (not shown) through a peripheral bus 110 and to an I/O controller 114 through an expansion bus 116 . The I/O controller 114 is also connected to various peripheral devices (not shown) through an I/O bus 118 . The system controller 106 includes a memory controller 120 that is coupled to a dynamic random access memory (“DRAM”) 122 through an address bus 126 , a control bus 128 , and a data bus 130 . The DRAM 122 includes a DRAM array 140 that stores data. The locations in the DRAM 122 to which data are written and data are read are designated by addresses coupled to the DRAM 122 on the address bus 126 . The operation of the DRAM 122 is controlled by control signals coupled to the DRAM 122 on the control bus 128 . These control signals can cause the DRAM 122 to operate in various refresh modes, such as a “self-refresh” mode in which periodic refresh cycles are periodically initiated without the need to apply control signals to the DRAM 122 . The DRAM 122 also includes ECC logic 144 that is operable to generate syndromes corresponding to data stored in the DRAM array 140 , and to check and, if necessary, correct data. The operation of the ECC logic 144 is controlled by an ECC controller 146 . The syndromes generated by the ECC logic 144 are stored in a syndrome memory 148 .
According to one embodiment of the invention, the DRAM 122 enters a reduced power mode refresh mode, such as a self-refresh mode, at step 150 using the process shown in FIG. 2 . In step 152 , the ECC controller 146 initializes an address to a first address in the DRAM array 140 . This address is preferably the address for the first row of memory cells in the DRAM array 140 since the refresh of the DRAM array 140 is performed on a row-by-row basis. In step 154 , the ECC controller 146 causes data stored in the DRAM array 140 at a current address (which is initially the first address) and a corresponding syndrome and flag bit to be transferred from the DRAM array 140 and the syndrome memory 148 , respectively, to the ECC logic 144 . In transferring the data from the DRAM array 140 , the memory cells storing the data are inherently refreshed.
The ECC logic 144 initially does not use the syndrome to check the read data. Instead, the ECC logic 144 checks to see if a flag bit appended to the syndrome has been set at step 160 . The flag bit is an extra bit appended to the syndrome that indicates whether the stored data corresponding to the syndrome has been modified since the ECC syndrome was generated. The first time the DRAM 122 enters the reduced power refresh mode, a syndrome will not have been generated for the data, and the flag bit will not have been set. Therefore, the process branches to step 164 where the ECC logic 144 generates a syndrome corresponding to the data. The ECC controller 146 then causes the syndrome and set flag bit to be written to the syndrome memory 148 at step 168 . A check is then made at step 170 to determine if the data transferred to the ECC logic 144 was stored in the DRAM array 140 at the last address in the DRAM array 140 . If it is, the process ends at step 174 until the low power refresh is again initiated at step 150 . If the data is not from the last address in the DRAM array 140 , the address is incremented at step 176 , and the process returns to step 154 .
When the DRAM 122 subsequently enters the reduced power refresh mode, the process shown in FIG. 2 again starts at 150 . The ECC controller 146 again initializes an address to a first address in the DRAM array 140 and then causes data stored in the DRAM array 140 and a corresponding syndrome and flag bit to be transferred to the ECC logic 144 . In transferring the data from the DRAM array 140 , the memory cells storing the data are again refreshed. The ECC logic 144 again checks to see if a flag bit appended to the syndrome has been set at step 160 . If the DRAM array 140 was previously refreshed in the reduced power mode and if no data have been written to the memory cells corresponding to the current address since the last refresh, the flag bit will still be set. The process shown in FIG. 2 then branches directly to step 170 , thus bypassing step 164 where a syndrome is generated and step 168 where the syndrome and set flag bit are written to the syndrome memory 148 . The process then loops through steps 154 - 176 until the entire DRAM array 140 has been refreshed. The use of ECC techniques in the reduced power refresh mode allows refresh to occur at a rate that is sufficiently low that data retention errors can be expected since a limited number of data retention errors can be corrected As is well known in the art, ECC techniques allow a limited number of bits to be corrected. Therefore, the refresh rate in the reduced power refresh mode should not be so low that more errors are generated in a group of data than can be corrected by the ECC techniques. This reduced refresh rate can significantly reduce the power consumed by the DRAM 122 .
It is possible for the data stored in the DRAM array 140 to be modified between refreshes by, for example, writing data to the DRAM array 140 . For this reason, each time data are written to the DRAM array 140 , the ECC logic 144 resets the flag bit appended to the syndrome corresponding to the data stored in the memory cells to which the data are written.
One of the advantages of using the process shown in FIG. 2 is that, in many cases, it will be necessary to generate and store syndromes for very few memory cells in the DRAM array 140 . When the DRAM 122 is idle, as it generally will be when in a reduced power refresh mode, such as a self-refresh mode, data will not be written to the DRAM array 140 . As a result, the flag bit appended to almost all syndromes will still be set, thus making it unnecessary to generate and store syndromes for almost all of the memory cells in the DRAM array 140 . As a result, the power consumed by the DRAM 122 is reduced by the amount of power that would be consumed in performing these syndrome generating and storing operations. Without using the process shown in FIG. 2 , it would be necessary to generate and store syndromes for all of the data stored in the DRAM array 140 each time the reduced power refresh mode was entered thereby consuming substantially more power.
The reduced power refresh mode of the DRAM 122 also may be conducted using alternate processes. For example, prior to entering a reduced power refresh mode, the ECC logic 144 can generate a syndrome from all of the data stored in the DRAM array 140 , and each generated syndrome and a set flag bit can then be stored in the syndrome memory 148 . As a result, the ECC logic 144 will not detect a flag bit that has not been set when performing the first refresh in the reduced refresh mode.
A process that is similar to the process shown in FIG. 2 can also be used to reduce power consumption when background ECC techniques are being used to insure the integrity of data stored in the DRAM 122 . As with the process shown in FIG. 2 , each time data are written the DRAM array 140 , the flag bit of a corresponding syndrome is reset. The process, which is shown in FIG. 3 , is entered at 200 when the integrity of a group of data, such as data stored in an entire row, is to be checked. The ECC controller 146 initializes an address to a first address in the DRAM array 140 at step 202 . This address is preferably the address for the first row of memory cells in the DRAM array 140 . In step 204 , the ECC controller 146 causes data stored in the DRAM array 140 at the current address, a corresponding syndrome and a corresponding flag bit to be transferred from the DRAM array 140 and the syndrome memory 148 , respectively, to the ECC logic 144 . The ECC logic 144 checks to see if a flag bit appended to the syndrome is set at step 208 . If the flag bit is set, meaning that the data has not been modified since the last integrity check, the ECC logic 144 uses the syndrome to determine if any data retention errors have arisen at step 210 . If the syndrome indicates the data are in error, the syndrome is used to correct the error at step 214 . The corrected data are then written to the DRAM array 140 at step 218 before progressing to step 220 . If no data retention error was detected at step 210 , the process branches directly to step 220 .
If the ECC logic 144 determines at step 208 that the flag bit is not set, meaning that the data corresponding to the syndrome have been modified, the process branches to step 224 where the ECC logic 144 generates a new syndrome. This syndrome, as well as a set flag bit, are then written to the syndrome memory 148 at step 226 before branching to step 220 .
At step 220 , a check is made to determine if the data transferred to the ECC logic 144 for integrity checking was stored in the final address of the DRAM array. If so, the process ends at step 222 until the integrity check is again initiated at step 200 . Otherwise, the address is incremented at step 228 , and the process returns to step 204 .
The use of the process shown in FIG. 3 can considerably reduce the power consumed by the DRAM 122 since it will often not be necessary to generate and store syndromes for the data stored in the DRAM array 140 . Instead, it will be necessary to generate and store a syndrome for data only if the data have been modified. If there was no way of determining if the data had changed; it would be necessary to generate and store a syndrome each time data was written to the DRAM 122 . Furthermore, if the syndrome did not match data stored in the DRAM array 140 , there would be no way to determine if a data retention error had occurred (in which case the syndrome should be used to generate and store corrected data) or if new data had been written to that location (in which case the syndrome should not be used to generate and store corrected data).
A synchronous DRAM (“SDRAM”) 300 according to one embodiment of the invention is shown in FIG. 4 . The SDRAM 300 includes an address register 312 that receives bank addresses, row addresses and column addresses on an address bus 314 . The address bus 314 is generally coupled to a memory controller like the memory controller 120 shown in FIG. 1 . Typically, a bank address is received by the address register 312 and is coupled to bank control logic 316 that generates bank control signals, which are described further below. The bank address is normally coupled to the SDRAM 300 along with a row address. The row address is received by the address register 312 and applied to a row address multiplexer 318 . The row address multiplexer 318 couples the row address to row address latch & decoder circuit 320 a - d for each of several banks of memory cell arrays 322 a - d , respectively.
One of the latch & decoder circuits 320 a - d is enabled by a control signal from the bank control logic 316 depending on which bank of memory cell arrays 322 a - d is selected by the bank address. The selected latch & decoder circuit 320 applies various signals to its respective bank 322 as a function of the row address stored in the latch & decoder circuit 320 . These signals include word line voltages that activate respective rows of memory cells in the banks 322 a - d.
The row address multiplexer 318 also couples row addresses to the row address latch & decoder circuits 320 a - d for the purpose of refreshing the memory cells in the banks 322 a - d . The row addresses are generated for refresh purposes by a refresh counter 330 . The refresh counter 330 periodically increments to output row addresses for rows in the banks 322 a - d . During operation in the low power, reduced refresh rate mode described above, the refresh counter 330 causes the memory cells in the banks 322 a - d to be refreshed at a rate that is sufficiently low that data errors are likely to occur. Refreshing the memory cells at this low rate causes relatively little power to be consumed during self-refresh or other reduced refresh periods. During operation in a normal refresh mode, the refresh counter 330 periodically increments at a normal refresh rate that generally does not result in data retention errors during a normal refresh mode. The refresh of the memory cells is typically performed every 64 ms.
After the bank and row addresses have been applied to the address register 312 , a column address is applied to the address register 312 . The address register 312 couples the column address to a column address counter/latch circuit 334 . The counter/latch circuit 334 stores the column address, and, when operating in a burst mode, generates column addresses that increment from the received column address. In either case, either the stored column address or incrementally increasing column addresses are coupled to column address & decoders 338 a - d for the respective banks 322 a - d . The column address & decoders 338 a - d apply various signals to respective sense amplifiers 340 a - d through column interface circuitry 344 . The column interface circuitry 344 includes conventional I/O gating circuits, DQM mask logic, read data latches for storing read data from the memory cells in the banks 322 a - d and write drivers for coupling write data to the memory cells in the banks 322 a - d.
The column interface circuitry 344 also includes an ECC generator/checker 346 that essentially performs the same function as the ECC logic 144 in the DRAM 122 of FIG. 1 . The ECC generator/checker 346 may be implemented by conventional means, such as by chains of exclusive OR gates implementing a Hamming code. Syndromes corresponding to the data stored in the memory cells in the banks 322 a - d and corresponding flag bits may be stored in one or more of the banks 322 a - d . Data from one of the banks 322 a - d are sensed by the respective set of sense amplifiers 342 a - d . When data are transferred from the memory cells of the banks 322 a - d during the reduced power refresh mode, the corresponding syndrome and flag bit is coupled to the ECC generator checker 346 . The ECC generator/checker 346 then checks and, if necessary, corrects the data as explained above. In the event data are being coupled from the banks 322 a - d for a read operation, the data are coupled to a data output register 348 , which applies the read data to a data bus 350 . Data read from one of the banks 322 a - d may be coupled to the data bus 350 through the data output register 348 without be processed by the ECC generator/checker 346 . Alternatively, the read data may be processed by the ECC generator/checker 346 to detect and correct errors in the read data.
Data to be written to the memory cells in one or more of the banks 322 a - d are coupled from the data bus 350 through a data input register 352 directly to write drivers in the column interface circuitry 344 without interfacing with the ECC generator/checker 346 . However, the flag bit corresponding to the write data is reset as explained above to indicate that any data stored in the location where the data are written has been modified. Alternatively, write data may be coupled to the ECC generator/checker 346 so it can generate a corresponding syndrome. The write data, the corresponding syndrome and a set flag bit are then coupled to write drivers in the column interface circuitry 344 , which couple the data, syndrome and flag bit to the memory cells in one of the banks 322 a - d . A pair of complementary data mask signals “DQML” and “DQMH” may be applied to the column interface circuitry 344 and the data output register 348 to selectively alter the flow of data into and out of the column interface circuitry 344 , such as by selectively masking data to be read from the banks of memory cell arrays 322 a - d.
The above-described operation of the SDRAM 300 is controlled by control logic 356 , which includes a command decoder 358 that receives command signals through a command bus 360 . These high level command signals, which are typically generated by a memory controller such as the memory controller 120 of FIG. 1 , are a clock chip select signal CS#, a write enable signal WE#, a column address strobe signal CAS#, and a row address strobe signal RAS#, with the “#” designating the signal as active low. Various combinations of these signals are registered as respective commands, such as a read command or a write command. The control logic 356 also receives a clock signal CLK and a clock enable signal CKE, which allow the SDRAM 300 to operate in a synchronous manner. The control logic 356 generates a sequence of control signals responsive to the command signals to carry out the function (e.g., a read or a write) designated by each of the command signals. The control logic 356 also applies signals to the refresh counter 330 to control the operation of the refresh counter 230 during refresh of the memory cells in the banks 322 . The control signals generated by the control logic 356 , and the manner in which they accomplish their respective functions, are conventional. Therefore, in the interest of brevity, a further explanation of these control signals will be omitted.
The control logic 356 also includes a mode register 364 that may be programmed by signals coupled through the command bus 360 during initialization of the SDRAM 300 . The mode register 364 then generates a mode bit that is used by the control logic 356 to enable the reduced power ECC modes described above with respect to FIGS. 2 and 3 . Finally, the control logic 356 also includes an ECC controller 370 that essentially performs the functions of the ECC controller 146 in the DRAM 122 of FIG. 1 . The ECC controller 146 causes the control logic 356 to issue control signals to the ECC generator/checker 346 and other components to generate syndromes and flag bits for storage in the banks 322 a - d , and to check and correct data read from the banks 322 a - d using the stored syndromes and flag bits.
Although the SDRAM device 300 can have a variety of configurations, in one embodiment the storage of data in the SDRAM device 300 is organized as shown in FIG. 5 . As shown in FIG. 5 , each row of memory cells in the DRAM array 140 contains 128 column groups, and each column group contains 128 bits of data arranged as 8 16-bit words plus an additional 9 bits that are used to store an 8-bit ECC syndrome and 1 flag bit. The 8 syndrome bits are capable of correcting a single bit error in the respective column group. If the ability to correct a larger number of bits is desired, then the number of syndrome bits can be increases accordingly.
One disadvantage of the arrangement for storing data as shown in FIG. 5 is that each column group contains an odd number of bits, i.e., 128 data bits, 8 syndrome bits and 1 flag bit. However, memory devices generally use rows with an even number of columns. To alleviate this disadvantage, data can be stored in the SDRAM device 300 using organization shown in FIG. 6 . As shown in FIG. 6 , each row of memory cells in the DRAM array 140 contains 256 column groups, and each column group contains 64 bits of data arranged as 4 16-bit words plus an additional 8 bits that are used to store a 7-bit ECC syndrome and 1 flag bit. The 7 syndrome bits are capable of correcting a single bit error in the 64 bits in the respective column group. As a result, each column group now contains an even number of bits, i.e., 64 data bits, 7 syndrome bits and 1 flag bit.
Although the present invention has been described with reference to the disclosed embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. For example, although the reduced power refresh mode has been described in the context of a self-refresh reduced power mode, it will be understood that it may also be used in other refresh modes. Other variations will also be apparent to one skilled in the art. Accordingly, the invention is not limited except as by the appended claims.
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A DRAM device includes an ECC generator/checker that generates ECC syndromes corresponding to items of data stored in the DRAM device. The DRAM device also includes an ECC controller that causes the ECC syndromes to be stored in the DRAM device. The ECC controller also causes a flag bit having a first value to be stored in the DRAM device when a corresponding ECC syndrome is stored. The ECC controller changes the flag bit to a second value whenever the corresponding data bits are modified, this indicating that the stored syndrome no longer corresponds to the stored data. In such case, the ECC controller causes a new ECC syndrome to be generated and stored, and the corresponding flag bit is reset to the first value. The flag bits may be checked in this manner during a reduced power refresh to ensure that the stored syndromes correspond to the stored data.
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FIELD OF THE INVENTION
The present invention relates to an improved method for selectively preparing 3-oxo-4-aza-5α-androstane compound under mild conditions.
DESCRIPTION OF THE PRIOR ART
Finasteride (17β-(N-tert-butylcarbamoyl)-5α-4-aza-androst-1-en-3-on), the compound of formula (II) having an androstane backbone, is effective in treating benign prostatic hypertrophy and androgenetic alopecia:
Benign prostatic hypertrophy and androgenetic alopecia are caused by binding of 5α-dihydrotestosterone (DHT) derived from testosterone to androgen receptor. The conversion of testosterone into 5α-dihydrotestosterone is mediated by testosterone 5α-reductase which is inhibited by finasteride. Such inhibition of 5α-dihydrotestosterone by finasteride results in rapid recovery of prostate and increased hair growth. Finasteride thus is effective to benign prostatic hypertrophy and good agent for treating androgenic alopecia which exhibits only low, temporary side effects, and it is the only orally administrable among the two hair-growth agents approved by FDA of the United Sates.
Finasteride can be conventionally prepared by converting the carboxylic group of the 17β-position of 3-oxo-4-aza-5α-androstane-17β-carboxylic acid of formula (I) into a t-butylcarbamoyl group and then carrying out dehydrogenation at the 1,2-positions, or carrying out dehydrogenation at the 1,2-positions and then converting the 17β-position carboxylic group into a t-butylcarbamoyl group:
For example, a process for preparing 3-oxo-4-aza-5α-androstane-17β-carboxylic acid of formula (I) is disclosed in U.S. Pat. No. 4,760,071 and the J. Med. Chem. 29, 2298 (1986), wherein the 3-oxo-4-aza-5-androstene compound of formula (III) is reduced with the hydrogen in the presence of a PtO 2 catalyst under a hydrogen atmosphere of 40 psi to produce the compound of formula (I).
The above reduction process selectively produces the compound of formula (I) having the 5-hydrogen oriented at 5α-position, without giving the isomer thereof, the compound of formula (IV) having the 5-hydrogen at the 5β-position. However, this asymmetric reduction process requires the use of explosive hydrogen and an expensive catalyst under high pressure condition.
Also disclosed in J. of Pharmaceutical Sciences. 63, p 19 (1974) is a method of reducing a steroid compound having a structure similar to the compound of formula (III) to produce a 5α-compound using formic acid and N-methylformamide. However, this process is conducted under high temperature and high pressure conditions and gives a poor productivity.
SUMMARY OF THE INVENTION
Accordingly, it is a primary object of the present invention to provide an improved method for selectively preparing the compound of formula (I) under mild conditions.
In accordance with the present invention, there is provided a method for preparing the compound of formula (I) comprising heating the compound of formula (III) in a mixture of formic acid and an alkanediol in the presence of zinc:
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and features of the present invention will become apparent from the following description of the invention taken in conjunction with the following accompanying drawings, which respectively show:
FIG. 1 : a high performance liquid chromatography (HPLC) scan of the compound of formula (I) prepared in accordance with the inventive method; and
FIG. 2 : an HPLC scan of the compound of formula (I) prepared in Comparative Example 1 in the absence of zinc; and
FIG. 3 : an HPLC scan of the compound of formula (I) prepared in Comparative Example 2 using formic acid and methylformamide.
DETAILED DESCRIPTION OF THE INVENTION
The compound of formula (III) used as a starting material of the present invention can be prepared by a conventional method (U.S. Pat. No. 4,760,071 and the J. Med. Chem. 29, 2298 (1986)).
In accordance with the present invention, the compound of formula (I) can be prepared by dissolving the compound of formula (III) in a mixture of formic acid and an alkanediol, adding activated zinc thereto, and heating the resulting mixture.
In the inventive method, formic acid may be used in an amount of 3 to 30 ml, preferably 5 to 15 ml based on 1.0 g of the compound of formula (III); and the alkanediol, in an amount of 2 to 20 ml, preferably 5 to 10 ml, based on 1.0 g of the compound of formula (III).
The alkanediol which may be used in the present invention includes ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol and 2,3-butandiol, and the like, among which ethylene glycol is preferred.
The zinc used in the present invention enhances both the selectivity of the target 5α-compound and the yield, and also reduces the reaction time. Zinc may used in 4 to 10 equivalents, preferably, 6 to 8 equivalents, based on a mole of the compound of formula (III), and in the total absence of the isomeric 5β-byproduct, the target 5α-compound is produced in a high yield of 80%. When zinc is not used, the target 5α-compound is produced in a yield of only about 50% together with 10 to 20% of the isomeric 5β-compound.
The reduction in accordance with the present invention may be carried out at a temperature of 80 to 130° C., preferably 100 to 110° C., for 4 to 8 hours.
Thus, in accordance with the simple method of the present invention, the target compound of formula (I) can be selectively produced in a high yield under mild conditions.
The present invention will be described in further detail with reference to Examples. However, it should be understood that the present is not restricted by the specific Examples.
EXAMPLE
Preparation 1: Preparation of 17β-carboxy-5-oxo-A-nor-3,5-secoandrostan-3-onic acid
16 g (50 mmol) of 3-oxo-4-androstene-17β-carboxylic acid was dissolved in 240 ml of t-butanol, 16 g (150 mmol) of sodium carbonate dissolved in 40 ml of water was added thereto, and then heated to 80° C. Added dropwise thereto was a solution, which is preheated to 60° C., of 53.5 g (250 mmol) of sodium metaperiodate and 4.0 g (25 mmol) of potassium permanganate dissolved in 300 ml of water. The resulting mixture was refluxed for 3 hours and left at room temperature overnight. The inorganic materials were filtered-off through celite, the filtrate was successively washed with water and 250 ml of 10% sodium hydrogen sulfite, t-butanol was removed under a reduced pressure, and the residue was acidified with concentrated HCl. The acidified residue was then extracted with 320 ml of methylene chloride, washed successively with 320 ml of 5% sodium hydrogen sulfite and 320 ml of brine, and distilled under a reduced pressure, to obtain 14.5 g of the title compound (yield: 86%) as a pale yellow solid.
H-NMR(δ, CDCl 3 ): 0.82(3H, 19-CH 3 ), 1.16(3H, 18-CH 3 ), 1.20˜2.30 (15H, cyclic-CH), 1.53(2H, 1-CH 2 ), 2.40(2H, 2-CH 2 ), 2.50(1H, 17-CH), 11.85(1H, COOH)
Preparation 2: Preparation of 3-oxo-4-aza-5-androstene-17β-carboxylic acid (the Compound of Formula (III))
10 g of 17β-carboxy-5-oxo-A-nor-3,5-secoandrostan-3-onic acid (30 mmol) obtained in Preparation 1 was dissolved in 30 ml of ethylene glycol, and 75 ml of 2.0M ethanolic ammonia solution (150 mmol) was added thereto, stirred for an hour at 40 to 50° C., and refluxed for 12 hours. The resulting mixture was cooled to room temperature and ethanol was distilled off under a reduced pressure. To the residue was added 150 ml of water and the resulting mixture was acidified with 10% HCl to pH 1.5. Precipiates formed were filtered, washed with water, and dried at 45° C., to obtain 6.6 g of the title compound (yield: 70%) as a white solid.
H-NMR(δ, DMSO-d 6 ): 0.57(3H, 19-CH 3 ), 0.91(3H, 18-CH 3 ), 0.95˜2.30 (18H, cyclic-CH), 4.76(1H, 6-CH), 9.17(1H, NH), 11.85(1H, COOH)
Example 1
3-oxo-4-aza-5α-androstane-17β-carboxylic acid (the Compound of Formula (I)-1)
3.2 g (10 mmol) of 3-oxo-4-aza-5-androstene-17β-carboxylic acid obtained in Preparation 2 was dissolved in a mixture of 45 ml of formic acid and 15 ml of ethylene glycol, and 2.6 g (80 mmol) of activated zinc was added thereto. The mixture was reacted for 8 hours at 100 to 105° C. and cooled to room temperature. The suspended solid was removed by filteration, and the solvent in the filtrate was removed under a reduced pressure. 13 ml of N-methylformamide was added to the residue, and the resulting mixture was stirred for 30 minutes in an ice bath. Precipitates formed were then filtered and dried at 45° C., to obtain 2.6 g of the title compound (yield: 81%) as a white solid.
The product thus obtained was analyzed by HPLC and the result is shown in FIG. 1 . As can be seen in FIG. 1 , only the target 5α-compound (retention time: 11.996) is detected, the isomeric 5β-compound being not detectable.
H-NMR(δ, DMSO-d 6 ): 0.56(3H, 19-CH 3 ), 0.72(3H, 18-CH 3 ), 0.80˜1.30 (8H, cyclic-CH), 1.40˜1.70(7H, cyclic-CH), 1.87(2H, 16-CH), 2.10(2H, 2-CH 2 ), 2.30(1H, 17-CH), 3.0(1H, 5-CH), 7.15(1H, NH), 11.85(1H, COOH)
Example 2
3-oxo-4-aza-5α-androstane-17β-carboxylic acid (the Compound of Formula (I)-2)
3.2 g (10 mmol) of 3-oxo-4-aza-5-androstene-17β-carboxylic acid obtained in Preparation 2 was dissolved in a mixture of 16 ml of formic acid and 32 ml of ethylene glycol, and 2.6 g (80 mmol) of activated zinc was added thereto. The mixture was reacted for 8 hours at 110 to 120° C., and cooled to room temperature. The suspended solid was removed by filtration, formic acid was removed under a reduced pressure. The residue was dissolved in 300 ml of chloroform and washed successively with 150 ml portions of 5% aqueous sodium carbonate solution (×2) and 150 ml portions of water (×3). The chloroform layer was separated, then dried, filtered and the solvent was removed under a reduced pressure. 13 ml of N-methylformamide was added to the residue and stirred for 30 minutes in an ice bath. Precipitates formed were then filtered and dried at 45° C., to obtain 2.7 g of the title compound (yield: 83%) as a white solid.
The product thus obtained was analyzed by HPLC and the result showed that only the 5α-compound (retention time: 11.996) was produced. H-NMR data was the same as in Example 1.
Comparative Example 1
Preparation of 3-oxo-4-aza-5α-androstane-17β-carboxylic acid (the Compound of Formula (I)) in the Absence of Zinc
3.2 g (10 mmol) of 3-oxo-4-aza-5-androstene-17β-carboxylic acid obtained in Preparation 2 was dissolved in a mixture of 45 ml of formic acid and 15 ml of ethylene glycol, and reacted for 8 hours at 100 to 105° C. The reaction mixture was cooled to room temperature, the residual solid was remove by filtration and the solvent was distilled off under a reduced pressure. 13 ml of N-methylformamide was added to the resulting residue and stirred for 30 minutes in an ice bath. Precipitates formed were then filtered and dried at 45° C., to obtain 1.7 g of the title compound (yield: 53%) as a white solid.
The product thus obtained was analyzed by HPLC and the result is shown in FIG. 2 , wherein the area of 5β-compound peak (retention time: 12.956) is 15% relative to the area of the 5α-compound peak (retention time: 12.187) of 85%. That is, a large amount of the undesired 5β-compound is produced.
Comparative Example 2
Preparation of 3-oxo-4-aza-5α-androstane-17β-carboxylic acid (the Compound of Formula (I)) Using a Mixture of Formic Acid and N-methylformamide
3.2 g (10 mmol) of 3-oxo-4aza-5-androstene-17β-carboxylic acid obtained in Preparation 2 was dissolved in a mixture of 45 ml of formic acid and 15 ml of N-methylformamide, and reacted for 8 hours at 100 to 105° C. The reaction mixture was cooled to room temperature, the residual solid was filtered off, formic acid was removed under a reduced pressure, and the remaining solution was stirred for 30 minutes in an ice bath. Precipitates formed were then filtered and dried at 45° C., to obtain 1.9 g of the target compound (yield: 59%) as a white solid.
The product thus obtained was analyzed by HPLC and the result is shown in FIG. 3 , wherein the area of the 5β-compound peak (retention time: 12.770) is 35% relative to the 5α-compound peak (retention time: 12.046) of 65%. That is, a large amount of the undesired 5β-compound is produced.
While the invention has been described with respect to the specific embodiments, it should be recognized that various modifications and changes may be made by those skilled in the art to the invention which also fall within the scope of the invention as defined as the appended claims.
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This invention relates to a method for selectively preparing the 3-oxo-4-aza-5¥á-androstane compound which is used as an intermediate of finasteride by heating 3-oxo-4-aza-5-androstene in a mixture of formic acid and an alkanediol in the presence of zinc.
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[0001] The present invention relates to the field of composite materials comprising a polymeric matrix reinforced by a fibrous structure, and more particularly, the use of such materials in manufacturing aeronautical or turbo-machine parts.
[0002] In the aeronautical field, there is a need to reduce the mass of components of engines while maintaining at a high level the mechanical properties thereof. In a multiflux turbo-engine, the blower casing defining the contour of the air vein entering the engine and inside which the rotor of the blower is located is now made of a composite material. It comprises a ferrule provided upstream and downstream with, both radial and transversal, external flanges, for linking and mounting to other components of the engine, including the air inlet profile upstream and the intermediary casing downstream. The casing supports various elements and should be able to retain objects resulting from a blower blade breaking.
[0003] A method for manufacturing a part such as a blower casing made of a composite material comprises arranging a fibrous structure on a mandrel, the profile of which corresponds to that of the part to be achieved. The fibrous reinforcement could be manufactured, for instance, through three dimension weaving with a progressive thickness as described in patent EP 1 961 923 in the name of the assignee. The fibrous reinforcement is made with a tubular fibrous preform forming a single part with reinforcing parts corresponding to the flanges of the casing. Manufacturing is done with the structure being compacted and impregnated by a resin and the latter being polymerized in order to achieve the part.
[0004] This invention relates to a manufacturing method wherein impregnating the fibrous reinforcing part is achieved by the RTM injecting method, being the acronym for Resin Transfer Moulding. According to this method, the fibrous structure is enclosed while being compacted in a rigid mould with a stiffened geometry, having its shape corresponding to the part that is to be obtained, and the resin is injected inside the mould after vacuuming the case being. The mould comprises a first part forming a support for the fibrous structure and a counter mould being put on top of the fibrous structure. The structure is compacted by bringing closer the walls of both parts of the mould.
[0005] The content of fibres is an important parameter for designing a part of such a type. More particularly, for a part such as a casing with a conical vein and integrated flanges, it is important that the content of fibres be high, both in the vein area as in the flanges. Thus, it is required to apply compaction stresses with different orientations depending on the areas of the part without hindering the closure of the mould and damage the integrity of the fibrous reinforcement.
[0006] The designs of the prior art injection moulds, for such a type of part, do not allow to apply satisfactory compaction stresses in the areas of the flanges. Indeed, a counter mould made in a single piece is moved following a direction perpendicular to the main surface of the support and all the parts of the support are therefore not oriented favourably with respect to the shift direction. This results in a final layout of the fibres in such areas not being optimum from the mechanical strength point of view.
DESCRIPTION OF THE INVENTION
[0007] This invention aims at providing a method for manufacturing a cylindrical part, having radially oriented flanges, allowing for both the requirement of the highest possible content of fibres resulting from the fibrous structure being compacted and the optimum orientation of the fibres to be combined.
[0008] Such an objective is achieved with a method for manufacturing an item made of a composite material formed with a polymeric matrix reinforced with a fibrous structure, comprising the steps of positioning the fibrous structure on a support forming a moulding surface, covering with a counter mould and compacting said structure through the surface of the counter mould being brought closer to that of the support, then of injecting of the polymer matrix in said fibrous structure, characterized in that, the support comprising a cylindrical part and a wall radially oriented with respect to the cylindrical part, the counter mould comprises two parts able to move one relative to the other being moved in a direction respectively one towards the axis of the cylindrical part and the other towards said radial wall.
[0009] The method of this invention has the advantage of being able to position and compact fibres, according to the required final product.
[0010] In so far as the orientation of the fibres is optimum within the enclosure of the mould, the method further offers the advantage of achieving the impregnation of resin in such a stiffened configuration.
[0011] An additional advantage lies in having the possibility to dry to the final shape, should the fibrous reinforcement require this.
[0012] Finally, the geometry of the connecting radii between the vein and the flanges is also ensured by means of such a method.
[0013] According to an embodiment, the counter mould comprises a main part having a shape complementary to that of the cylindrical part of the support et a corner with a first wall, having a shape complementary to that of said radial wall, being interposed between said main part of the counter mould and said radial wall of the support, the counter mould and the corner being arranged so that the corner moves perpendicularly in the direction towards said radial wall of the support when the counter mould is moved in the direction towards the cylindrical part.
[0014] More specifically, the corner has a second wall having a shape complementary to the wall portion of the cylindrical part being adjacent to that of said radial wall, and, advantageously, the corner has a wall portion with a rounded section between said first and second walls.
[0015] In order to more easily implement the method, a metal sheet is arranged under said second wall of the corner so as to improve gliding of the corner on the fibrous structure.
[0016] According to a feature, the central part of the counter mould comprising a wall portion slanted with respect to said axis, the corner comprising a third wall slanted with respect to said axis, said wall portions coming in contact one with the other in order to achieve gliding of the corner in the direction towards said radial wall when the counter mould is moved in the direction towards the cylindrical part.
[0017] More particularly, the counter mould is made of at least two cylinder sectors. According to the preferred embodiment, the support comprises a cylindrical part and two walls radially oriented on both sides of the cylindrical part. These two latter walls make up the flanges of the casing.
[0018] The counter mould is brought closer to the surface of the mould so as to compact the fibrous structure and reduce the thickness thereof both in the radial direction with respect to the axis of the cylindrical part as well as perpendicularly to the surface of the support after the counter mould has been positioned.
[0019] The method is applicable, more specifically, to manufacturing a casing for a turbo-machine.
SHORT DESCRIPTION OF THE FIGURES
[0020] Other characteristics and advantages of this invention will become evident from the following description, referring to the appended figures respectively showing:
[0021] FIG. 1 , an axial sectional schematic view of a front blower gas turbo-engine;
[0022] FIG. 2 , an axial half sectional view of a mould for manufacturing a blower casing;
[0023] FIG. 3 , a front sectional view of the mould along the direction III-III of FIG. 2 ; and
[0024] FIG. 4 , a perspective view of a corner element of the counter mould.
DETAILED DESCRIPTION OF AN EMBODIMENT
[0025] This invention is applied to the manufacture of a bypass turbojet blower casing, with an example thereof being schematically illustrated on FIG. 1 . The engine comprises from upstream to downstream, the flow direction of gases, a front blower 2 at the engine inlet, a feeding compressor, a HP compressor 3 , a combustion chamber 4 , and high and low pressure turbines 5 . The blower 2 is rotated by the turbine BP inside a blower casing 6 . The blower casing defines the air volume entering inside the engine. A part of such air, constituting the primary flux, is guided inside the engine where it is successively pressed by the feeding compressor and the HP compressor. It feeds the combustion chamber 4 where its energy is increased by the combustion of the fuel. The gases being produced are expanded in the successive turbine stages and then ejected. The other part of the air constitutes the secondary flux, which is ejected in the atmosphere directly or after blending with the primary flux depending on the application of the engine. The engine is represented without the shell enclosing it. The blower casing 6 has a substantially frustoconical cylindrical shape with two flanges, one upstream 61 and the other downstream 62 . The upstream flange 61 comprises means for fastening the air inlet fairing (not shown). The downstream flange connects the casing to the structural casing 7 also referred to as the intermediary casing.
[0026] Such a casing is advantageously made in a composite material with a fibrous reinforcement being densified by a matrix. The fibrous material is, for instance, made of carbon, an aramid glass or other and the matrix is made of a polymer such as an epoxide, a bis maleimide ou a polyimide.
[0027] The fibrous reinforcement is formed through winding on a mandrel with a fibrous texture.
[0028] FIG. 2 illustrates an example of a device for moulding the casing. A support 20 has an external annular surface with the same profile as the part to be achieved, i.e. in the present case, the internal surface of the blower casing. Such a support comprises a cylindrical part 21 with the shape of a mandrel and is provided with two transversal flanges 22 et 23 shaped so as to allow for the flanges of the casing to be manufactured. According to the method, the fibrous reinforcement is positioned around the mandrel so as to achieve a preform 10 . The embodiment of the preform is not limitative. It could be made through winding distinct webs superimposed until the desired thickness is obtained, or through winding a web in several turns. The webs may have been plaited or even woven: the preform may also been achieved through threading a sleeve, either plaited or woven, around a mandrel or even through winding filaments around the mandrel.
[0029] The preform 10 comprises a central part 11 , the thickness thereof is not required to be constant along its whole length, more specifically over-thicknesses are provided on the part along the axis being perpendicular to the surface scanned by the blower blades. Those over-thicknesses enable to build a reinforcement able to absorb shocks from debris or other objects as a result of the blades breaking. The preform also extends along two end supporting parts in two radial portions 12 and 13 in order to achieve flanges.
[0030] The manufacture of the part proceeds through positioning a counter mould 30 on the preform so as to build a volume wherein the polymer of the matrix is injected with the help, if required, of a vacuum source. In the example, this counter mould comprises three parts 30 a, 30 b and 30 c, as illustrated on FIG. 3 ; the internal side of the counter mould 30 a 1 , 30 b 1 and 30 c 1 respectively is shaped depending on the form to be imparted to the external surface of the part. Each one of the parts gets stuck between both end supporting parts 22 and 23 . When all three parts are positioned, they provided for a closed volume with the mandrel 21 and the two supporting parts 22 et 23 .
[0031] As can be seen on FIG. 2 , the internal axial profile of each counter mould element comprises a central part 31 corresponding to the central part 11 of the preform and two end parts coming in abutment against the end radial part of the preform.
[0032] As a result of the large number of fibres, there is an interstitial vacuum being filled by the matrix upon the injection of the polymer. However, the content of fibres in the finished part is a first order parameter for the mechanical strength thereof. The porosity of the preform should thus be kept under control and be maintained within some limits.
[0033] This is why it is required to compact the fibrous structure constituted by the preform. Simply radially bringing the elements of the counter mould closer in the direction towards the preform would result in the thickness of the central part being reduced, but the end portions 12 and 13 would not be properly compressed. Surfaces sliding therebetween would result in beads or folds being formed. In order to overcome such a problem, two corner shaped counter mould elements 32 and 33 are provided in the area of the preform located in the vicinity of the radial portions 12 and 13 .
[0034] Each counter mould element with a corner shaped section extends following a circle arc with the counter mould element to which it is adjacent. There are illustrated in FIG. 3 , three corner shaped elements respectively associated with the counter mould elements 30 a, 30 b 30 c. Each corner 32 or 33 comprises a first wall 32 a, 33 a respectively opposite the radial portion 12 , 13 of the preform. It also comprises a second cylindrical wall portion 32 b, 33 b, perpendicular to the first wall 32 a, 33 a and opposite the central part 11 of the preform 10 , adjacent to the radial portion 12 , 13 . The two walls 32 a and 32 b, 33 a and 33 b are connected via a rounded section, preferably circle arc shaped, rounded section, 32 c, 33 c respectively. The two, first and second, walls join on a third wall 32 d, 33 d. This wall has a rectilinear section with a frustoconical portion shape.
[0035] On the counter mould element 30 adjacent to the corner element, the central part 31 is connected to two surface portions, on both sides, 31 d with a frustoconical shape, each respectively parallel to the surface portion 32 d, 33 d of the adjacent corner element 32 or 33 . Finally, the counter mould ends, on each side, with a wall portion 31 with the shape of a cylinder portion having the same axis as that of the support 20 and a radius equal to that of the flange to be achieved; the length thereof is also equal to the thickness of the flange to be achieved.
[0036] The various parts are arranged so that when the counter mould in a closing position of the mould, it provides, with the cylindrical part 21 , a determined thickness of the radially measured preform. Being brought closer, the surfaces 31 d come in abutment against the third walls of the corner elements 32 and 33 ; then, when the shift of the counter mould proceeds, an abutment stress is applied by the surfaces 31 d on the third walls 32 d and 33 d. Such a stress comprises a radial component and an axial component resulting in the corners 32 and 33 moving and in the thickness of the preform becoming reduced in the contact areas of the corners with the preform. More specifically, the axial stress applied by the first wall 32 a and 33 a is oriented perpendicularly to the radial portion, 12 and 13 respectively, of the preform. In order to facilitate the shift of the corner elements at the surface of the cylindrical part of the preform and to avoid any possible tearing, thin metal sheets are arranged between the corner and the preform. Sliding thus occurs without damaging the latter. The metal sheet can be removed subsequently. In the closing position of the mould, the surfaces 31 d of the counter mould are in contact with the surfaces 32 d, respectively 33 d, of the corner elements 32 and 33 and the corner is spaced apart from the wall of the supporting part by the distance as determined by the axial length of the cylindrical wall portion 31 e of the counter mould.
[0037] In summary, manufacturing a cylindrical part with a flange comprises the following steps. A preform formed with fibres is positioned on a cylindrical support 20 , the profile of which is that of the interior of the part to be manufactured. The preform is not compressed, the fibrous structure is abundant. Such a support comprises supporting parts at the end for moulding flanges. A counter mould 30 is arranged having several circle arc elements, at least two half a circle elements, around the preform 10 . Such a counter mould comprises corner shaped elements 32 and 33 on both sides of a central cylindrical part 31 . The counter mould is brought closer to the support coming in abutment via slanted sides against the corners and drives them in a motion, both radially to the axis of the cylinder and axially in the direction to the supporting parts. When the counter mould is positioned, the thickness of the wall of the preform has been reduced without any unwanted bead or fold. The elements are bolted therebetween in order to prevent them from bursting upon the matrix being injected.
[0038] The polymer constituting the matrix is then injected, optionally using some vacuum. Once the polymerization is achieved, the part is released and the finishing operations are performed.
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A method for manufacturing an article made of a composite material including a polymer matrix reinforced by a fibrous structure, the method including: placing the fibrous structure on a substrate; forming a molding surface, covering the structure with a mating mold; and compacting the structure by moving the surface of the mating mold toward the surface of the substrate. The substrate includes a cylindrical portion and a wall positioned radially relative to the cylindrical portion, and the mating mold includes two portions that are mobile relative to one another and that are moved toward the axis of the cylindrical portion and towards the radial wall of the substrate, respectively. The method can be used for example for manufacturing a fan casing of a turbojet engine.
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[0001] A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the reproduction of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
CROSS-REFERENCES TO RELATED APPLICATIONS
[0002] This application claims priority to and hereby incorporates by reference in its entirety U.S. Provisional Patent Application No. 61/870,114 entitled “EXPANDING GAS DIRECT IMPINGEMENT COOLING APPARATUS” filed on Aug. 26, 2013.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0003] Not Applicable
REFERENCE TO SEQUENCE LISTING OR COMPUTER PROGRAM LISTING APPENDIX
[0004] Not Applicable
BACKGROUND OF THE INVENTION
[0005] The present invention relates generally to cooling food. More particularly, the invention pertains to cooling packages of beverages using very little electrical power.
[0006] There are two options for cooling drinks on a large scale, large refrigerators or tubs of ice. Refrigerators cool packaged drinks (e.g., cans or bottles of a beverage) by storing the drinks in a refrigerator cabinet at a temperature between 32 degrees and 40 degrees Fahrenheit. Refrigerators require a lot of space (enough to hold all of the drinks) and a lot of electricity. If the refrigeration cabinet is frequently opened, then the temperature inside the cabinet may not remain low enough to keep the drinks cool, and the refrigerator will use additional electricity. Tubs of ice cool drinks by immersing them at a temperature between about 0 and 20 degrees Fahrenheit for a time to cool the drinks to between about 32 and 40 degrees Fahrenheit. Tubs of ice may be left open, but the ice will quickly melt (i.e., warm), and additional ice will be required to maintain a cool environment for the drinks. This requires making ice on site which requires machinery and electricity, or brining ice to the site which may prove difficult logistically.
[0007] For festivals or events in venues without adequate electricity, it is inefficient to bring in large refrigeration units and generators needed for refrigerating drinks. Similarly, bringing in an initial quantity and additional quantities of ice (or making additional ice with icemakers and generators) is also prohibitively inefficient, especially for longer events (e.g., multiple days).
BRIEF SUMMARY OF THE INVENTION
[0008] Aspects of the present invention provide a cooling system for packaged beverages. The system includes a cabinet or housing which may be insulated. The housing has a door and may optionally include shelves. The user places a quantity of packaged beverages into the housing and, via a user interface of the system, identifies the package type and quantity of the packaged beverages in the housing. The system injects a measured amount of liquefied gas (e.g., liquid nitrogen) into the cabinet and prevents the door from opening for a predetermined period of time based on the package type and quantity selected by the user. The door is then unlocked, an optional alert may be sounded, and the user can open the door to remove some or all of the packaged beverages from the cabinet which have been cooled to between about 30 and 40 degrees Fahrenheit.
[0009] In another aspect, a cooling system includes a housing, a gasification manifold, a valve, and a controller. The housing is configured to receive a beverage package in a chamber defined therein. The housing includes a door and an electronically controlled lock. The electronically controlled lock is operable to prevent the door from opening when engaged. The gasification manifold is operable to receive liquefied gas from the reservoir and provide liquefied gas to the chamber. The valve is operable to provide liquefied gas to the gasification manifold from the reservoir when the valve is open and prevent flow of the liquefied gas from the reservoir to the gasification manifold when the valve is closed. The controller is operable to selectively open and close the valve and to selectively engage the electronically controlled lock to selectively prevent the door from opening.
[0010] In another aspect, a cooling system includes a housing, a valve, and a controller. The housing is configured to receive a beverage package in a chamber defined therein. The housing includes a door and an electronically controlled lock. The electronically controlled lock is operable to prevent the door from opening when engaged. The valve is operable to provide the liquefied gas to the chamber from reservoir when the valve is open and prevent flow of liquefied gas from the reservoir to the chamber when the valve is closed. The controller is operable to selectively open and close the valve and to selectively engage the electronically controlled lock to selectively prevent the door from opening. The controller selectively engages in this engages the electronically controlled lock as a function of the beverage package.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0011] FIG. 1 is an isometric view of a packaged beverage cooling system.
[0012] FIG. 2 is a wire-frame front perspective view of a packaged beverage cooling system.
[0013] FIG. 3 is a front plan view of a packaged beverage cooling system.
[0014] FIG. 4 is a side plan view of a packaged beverage cooling system.
[0015] FIG. 5 is a rear plan view of a packaged beverage cooling system.
[0016] Reference will now be made in detail to optional embodiments of the invention, examples of which are illustrated in accompanying drawings. Whenever possible, the same reference numbers are used in the drawing and in the description referring to the same or like parts.
DETAILED DESCRIPTION OF THE INVENTION
[0017] While the making and using of various embodiments of the present invention are discussed in detail below, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.
[0018] To facilitate the understanding of the embodiments described herein, a number of terms are defined below. The terms defined herein have meanings as commonly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as “a,” “an,” and “the” are not intended to refer to only a singular entity, but rather include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the invention, but their usage does not delimit the invention, except as set forth in the claims.
[0019] As described herein, an upright position is considered to be the position of apparatus components while in proper operation or in a natural resting position as described herein. Vertical, horizontal, above, below, side, top, bottom and other orientation terms are described with respect to this upright position during operation unless otherwise specified. The term “when” is used to specify orientation for relative positions of components, not as a temporal limitation of the claims or apparatus described and claimed herein unless otherwise specified. The terms “above”, “below”, “over”, and “under” mean “having an elevation or vertical height greater or lesser than” and are not intended to imply that one object or component is directly over or under another object or component.
[0020] The phrase “in one embodiment,” as used herein does not necessarily refer to the same embodiment, although it may. Conditional language used herein, such as, among others, “can,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. Thus, such conditional language is not generally intended to imply that features, elements and/or states are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.
[0021] The terms “coupled” and “connected” mean at least either a direct electrical connection between the connected items or an indirect connection through one or more passive or active intermediary devices.
[0022] The term “circuit” means at least either a single component or a multiplicity of components, either active and/or passive, that are coupled together to provide a desired function.
[0023] Terms such as “providing,” “processing,” “supplying,” “determining,” “calculating” or the like may refer at least to an action of a computer system, computer program, signal processor, logic or alternative analog or digital electronic device that may be transformative of signals represented as physical quantities, whether automatically or manually initiated.
[0024] Referring to FIGS. 1-5 , a cooling system 100 includes a housing 102 , a gasification manifold 104 , a valve 106 , and a controller 108 . The housing 102 is configured to receive a beverage package. The beverage package may be anything from a single can or bottle to a case of cans or bottles (e.g., 24 individual cans or bottles). Further, the beverage package may be a plurality of packs (e.g., 12 individual cans or bottles) or cases (e.g., 24 individual cans or bottles). The housing 102 defines a chamber 110 therein which ultimately receives the beverage package. In one embodiment, the housing 102 has insulated stainless steel walls that are approximately 35 mm thick. The walls may be vacuum insulated. The housing 102 further comprises a door 120 and an electronically controlled lock 122 . The electronically controlled lock 122 is operable to prevent the door 120 from opening when engaged. In one embodiment, the electronically controlled lock 122 is a solenoid operable to protrude from an edge of the door 122 into a cabinet of the housing 102 . In another embodiment, the electronically controlled lock 122 includes a motor operable to rotate a latch into a locked position or out of the locked position. In one embodiment, the chamber 110 is substantially cubic to promote uniform cooling of beverage packages within the chamber 110 . That is, the chamber 110 may have a height 150 , a width 152 , and a depth 154 that are relatively similar. In one embodiment, the chamber 110 has an inset to house a venturi exhaust system, such that the depth 154 and height 150 are slightly reduced at a back of the housing 102 . In this embodiment, the height 150 , width 152 , and depth 154 are each approximately 600 mm excluding the inset such that the total volume of the chamber 110 is approximately ⅛ of a cubic meter. In this embodiment, the
[0025] The gasification manifold 104 is operable to receive liquefied gas from a reservoir (e.g., a liquid nitrogen tank) and provide liquefied gas to the chamber 110 . In one embodiment, the reservoir is a liquid nitrogen vessel storing liquid nitrogen (LN2) at approximately −196 Celsius. In one embodiment, the gasification manifold 104 is annular (e.g., ring-shaped) and located at a top 156 of the chamber 110 . In one embodiment, the gasification manifold 104 has an outer diameter 160 that is between approximately 60% and 75% of the width 152 of the top 156 of the chamber 110 . In one embodiment, the gasification manifold includes a plurality of spray nozzles 180 . The spray nozzles 180 are operable to convert the liquefied gas (e.g., liquid nitrogen) to a mist which immediately atomizes and evaporates, cooling the chamber 110 . In one embodiment, the spray nozzles 180 are mounted at approximately 30° with respect to a plane defined by the top 156 of the chamber 110 . The spray nozzles 180 are angled inward to spray toward a center of the chamber 110 .
[0026] The valve 106 is operable to provide the liquefied gas to the gasification manifold 104 from the reservoir when the valve 106 is open and prevent flow of the liquefied gas from the reservoir to the gasification manifold 104 when the valve 106 is closed. In one embodiment, the valve 106 is an electronically actuated solenoid valve for use with liquid nitrogen. In one embodiment, the cooling system 100 further includes a regulator. Alternatively, the regulator may be integral with the liquefied gas reservoir. In one embodiment, the regulator communicates the liquefied gas from the reservoir to the valve 122 or from the valve 122 to the chamber 110 at approximately one bar of pressure in a rate of approximately 0.5 liters per minute. When the housing 102 and chamber 110 are already cooled form a previous cooling cycle, the flow rate may be reduced to 0.25 liters per minute. The chamber 110 generally cools to approximately −40 Celsius during a cooling cycle, and beverage packages continue cooling for approximately 5-10 minutes after removal from the chamber 110 following the cooling cycle.
[0027] The controller 108 is operable to selectively open and close the valve 106 to control flow of the liquefied gas from the reservoir to the chamber 110 . The controller 108 is further operable to selectively engage the electronically controlled lock 122 to selectively prevent the door 120 from opening. In one embodiment, the controller 108 selectively engages the electronically controlled lock 122 such that the door 120 is prevented from opening while the valve 106 is open. The controller 108 may further prevent the door 120 from opening for a predetermined period of time after opening the valve 106 . In one embodiment, the predetermined period of time is determined as a function of the beverage package. In one embodiment, the controller selectively engages and disengages the electronically controlled lock 122 as a function of the beverage package. This predetermined period of time determined as a function of the beverage package determines the minimum beverage package cooling time within the chamber 110 . In one embodiment, an open time of the valve 106 is constant regardless of the beverage package type or quantity. In another embodiment, the open time of the valve 106 is determined as a function of the beverage package. In one embodiment, the cooling system 100 further includes a temperature probe 202 disposed in the chamber 110 operable to provide temperature data to the controller 108 . The controller 108 may prevent opening the door via the electronically controlled lock 122 until temperature inside the chamber has normalized as determined from the temperature data from the temperature probe 202 .
[0028] In one embodiment, the cooling system 100 further includes a user interface 130 . The user interface 130 is operable to receive beverage package data from a user. The beverage package data is indicative of a type and a quantity of the beverage package in the chamber 110 . For example, the type of the beverage package may be glass bottles, aluminum bottles, or aluminum cans. The tide may further include container size. The beverage package quantity may be a number of 12 packs or cases, or a total number of individual packages. As described above, the controller 108 engages and disengages the electronically controlled lock 122 as a function of the beverage package type and quantity received via the user interface 130 to enforce a minimum cooling time based on the beverage package type and quantity. In one embodiment, the user interface 130 is a touchscreen interface that asks the user to select between package type (e.g., 12 ounce glass bottle or 12 ounce aluminum can) and select a quantity (e.g., number of 12 packs in the chamber 110 ). When the user selects the quantity, the controller 108 actuates the electronically controlled lock 122 , opens the valve 106 for a standardized open time, and subsequently disengages the electronically controlled lock 122 after a predetermined period of time corresponding to the type and quantity of beverage package entered by the user. As shown in FIG. 3 , the controller 108 and the user interface 130 are integral, but it is contemplated within the scope of the claims that the controller 108 may be separate from the user interface 130 . Further, although the user interface 130 shown herein is a touchscreen, the user interface 130 may include, for example, fixed buttons corresponding to a type and quantity of standard package. In one embodiment, the predetermined period of time that the controller 108 maintains the electronically controlled lock 122 in the locked state (i.e., engaged) ranges between 45 seconds and 240 seconds depending on package type and quantity entered by the user via the user interface 130 .
[0029] In one embodiment, the cooling system 100 further includes a fan 140 configured to draw gases (e.g., the now gaseous, evaporated liquid nitrogen) from the chamber 110 and an exhaust the gases outside of the chamber 110 when activated. In one embodiment, the controller 108 activates the fan 140 whenever the door 122 is open. In one embodiment, the fan 110 is configured as a Venturi exhaust system by flowing air through a secondary chamber 142 having a constriction where the secondary chamber 142 is in fluid communication with the chamber 110 . In one embodiment, the killing system 100 further includes a duct 144 configured to fluidly connect to the secondary chamber 142 (e.g., indirectly to the fan 140 ). The duct 144 is operable to conduct gases drawn from the chamber 110 by the fan 142 a location remote from the housing 102 (and chamber 110 ). In one embodiment, the predetermined period of time during which the controller 108 maintains the door 120 in a locked state to allow for cooling of the beverage package may be extended by, for example, 10 seconds while the controller 108 actuates the fan 140 to evacuate the now gaseous liquid nitrogen (i.e., LN2) from the chamber 110 .
[0030] In one embodiment, the cooling system 100 further includes a battery 190 and at least one solar cell 192 . The solar cell 192 and battery 190 are supported by the housing 102 . The battery 190 is configured to provide power to the controller 108 . The solar cell 192 is configured to charge the battery 190 . This enables the cooling system 100 to be used in remote locations without access to electricity, and reduces a caterer's reliance on outside systems, gasoline supplies, etc. In one embodiment, the battery 190 is a 12 volt battery which will provide about 18 hours of continuous operation when fully charged. The battery 190 may be charged by the solar cell 192 , or may be charged before deploying the cooling system 100 to a site. The battery 190 may be recharged or replaced on site by other methods such as swapping the battery 190 with a fully charged battery, connecting the battery 190 to generator power via a charger, or connecting the battery 190 to a vehicle electrical system.
[0031] In one embodiment, the cooling system 100 further includes a temperature probe 202 and a temperature gauge 204 . The temperature probe 202 is within the chamber 110 , and the temperature gauge 204 is visible on the outside of the housing 102 . In one embodiment, the temperature gauge 204 is integral with the user interface 130 . In one embodiment, the chamber 110 reaches a −40 Celsius temperature immediately after introduction of the liquefied gas into the chamber 110 . The temperature may normalize somewhat during the cooling cycle, but the temperature in the chamber 110 will generally not increase significantly during the beverage package cooling cycle (which generally will not exceed 240 seconds). Thus, even after removal from the chamber 110 , the beverage package may continue to cool for approximately 5-10 minutes in a phenomenon similar to (i.e., converse to) microwaving food. That is, in practice, the packaging of the beverage is relatively mildly affected by the cooling cycle while the liquid center of the beverage become very cold (sometimes partially freezing), and the temperature of beverage normalizes throughout after removal from the chamber 110 over the course of the next 5-20 minutes.
[0032] It will be understood by those of skill in the art that providing data to the system or the user interface may be accomplished by clicking (via a mouse or touchpad) on a particular object or area of an object displayed by the user interface, or by touching the displayed object in the case of a touchscreen implementation.
[0033] It will be understood by those of skill in the art that information and signals may be represented using any of a variety of different technologies and techniques (e.g., data, instructions, commands, information, signals, bits, symbols, and chips may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof). Likewise, the various illustrative logical blocks, modules, circuits, and algorithm steps described herein may be implemented as electronic hardware, computer software, or combinations of both, depending on the application and functionality. Moreover, the various logical blocks, modules, and circuits described herein may be implemented or performed with a general purpose processor (e.g., microprocessor, conventional processor, controller, microcontroller, state machine or combination of computing devices), a digital signal processor (“DSP”), an application specific integrated circuit (“ASIC”), a field programmable gate array (“FPGA”) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Similarly, steps of a method or process described herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. Although embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that various modifications can be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.
[0034] A controller, processor, computing device, client computing device or computer, such as described herein, includes at least one or more processors or processing units and a system memory. The controller may also include at least some form of computer readable media. By way of example and not limitation, computer readable media may include computer storage media and communication media. Computer readable storage media may include volatile and nonvolatile, removable and non-removable media implemented in any method or technology that enables storage of information, such as computer readable instructions, data structures, program modules, or other data. Communication media may embody computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism and include any information delivery media. Those skilled in the art should be familiar with the modulated data signal, which has one or more of its characteristics set or changed in such a manner as to encode information in the signal. Combinations of any of the above are also included within the scope of computer readable media. As used herein, server is not intended to refer to a single computer or computing device. In implementation, a server will generally include an edge server, a plurality of data servers, a storage database (e.g., a large scale RAID array), and various networking components. It is contemplated that these devices or functions may also be implemented in virtual machines and spread across multiple physical computing devices.
[0035] This written description uses examples to disclose the invention and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. 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 elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
[0036] It will be understood that the particular embodiments described herein are shown by way of illustration and not as limitations of the invention. The principal features of this invention may be employed in various embodiments without departing from the scope of the invention. Those of ordinary skill in the art will recognize numerous equivalents to the specific procedures described herein. Such equivalents are considered to be within the scope of this invention and are covered by the claims.
[0037] All of the compositions and/or methods disclosed and claimed herein may be made and/or executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of the embodiments included herein, it will be apparent to those of ordinary skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit, and scope of the invention. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the invention as defined by the appended claims.
[0038] Thus, although there have been described particular embodiments of the present invention of a new and useful EXPANDING GAS DIRECT IMPINGEMENT COOLING APPARATUS it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims.
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A cooling system for packaged beverages includes a cabinet or housing which may be insulated. The housing has a door and may optionally include shelves. The user places a quantity of packaged beverages into the housing and, via a user interface of the system, identifies the package type and quantity of the packaged beverages in the housing. The system injects a measured amount of liquefied gas (e.g., liquid nitrogen) into the cabinet and prevents the door from opening for a predetermined period of time based on the package type and quantity selected by the user. The door is then unlocked, an optional alert may be sounded, and the user can open the door to remove some or all of the packaged beverages from the cabinet which have been cooled to between about 30 and 40 degrees Fahrenheit.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a sample warper equipped with short feed belts and capable of winding a yarn with effectively reducing increase of the tension of yarns, which would unavoidably occur during conventional warping, particularly during orderly winding yarns on a warper drum in successive warp turns. The present invention relates also to a method for winding yarns on the warper drum in successive warp turns using the above-mentioned sample warper.
[0003] 2. Description of the Related Art
[0004] Conventional electronically-controlled sample warpers of the described type are exemplified by Japanese Patents Nos. 1,529,104 and 1,767,706 (U.S. Pat. No. 4,972,662 and European Patent No. 035480). The first-named Japanese publication discloses a sample warper W as shown in FIG. 9 of the accompanying drawings. The sample warper W of FIG. 9 comprises: a yarn introduction means 6 , rotatably mounted on one side surface of a warper drum A for winding a yarn on the warper drum A; a plurality of yarn selection guides 27 , associated with the yarn introduction means 6 and mounted on an end of a base Y supporting the warper drum A for association with the yarn introduction means 6 and, for moving angularly movable to project to a yarn exchanging position and retract to a standby position during yarn changing; a fixed creel B for supporting a plurality of bobbins 160 , which are associated with the plural yarn selection guides 27 and on which various kinds or a single kind of yarns 22 are to be wound, thereby confirming transferring of the yarns 22 between the yarn introduction means 6 and the yarn selection guides 27 so that the yarns are automatically changed and successively wound neatly on the warper drum A in a preset sequence.
[0005] In the sample warper W, the plural yarn selection guides 27 receive the plural yarns 22 , respectively, so that the individual yarns 22 of the fixed creel B can be successively wound on the warper drum W in a fully controlled manner. Reference numeral 17 designates a plurality of conveyer belts movably mounted on a circumferential surface of the warper drum A.
[0006] The second-named Japanese publication discloses another sample warper W for winding a plurality of yarns concurrently as shown in FIG. 10. The sample warper W of FIG. 10 has a plurality of yarn introduction means 6 a - 6 h (eight yarn introduction means are shown in FIG. 10) for winding a plurality of yarns 22 , which are paid out from a rotary creel F with a plurality of bobbins 160 , on the conveyer belts 17 .
[0007] Each of the sample warpers W shown in FIGS. 9 and 10 has a plurality of parallel lease members (a plurality of parallel lease rods 18 a - 18 g ) longitudinally extending alongside of the warper drum A. The basic structure and operation of the sample warpers W are well known as by the above-mentioned Japanese publications, so their detailed description is omitted here.
[0008] Japanese Patent No. 2854789 discloses a sample warper capable of winding a yarn orderly in successive turns independently of a number of turns so as to make a long sample or a small lot of product, namely, flexible manufacturing. The basic structure and operation of this sample warper are described in the above-mentioned Japanese publications, so their detailed description is omitted here.
[0009] When long size warping orderly in successive turns (in which the number of yarn windings increases) is conducted using the above-mentioned conventional sample warpers, a yarn 22 is wound directly on the conveyer belts 17 as shown in FIG. 11. In FIG. 11, reference numeral 16 designates a drum spoke, on which a conveyer belt 17 is movably mounted. Reference character G designates guide means for winding a yarn orderly in successive turns, and reference numeral 100 designates an attaching member for attaching the guide means G on a base end of the conveyer belt 17 . Since the yarn 22 is tightened on the conveyer belts 17 with a considerable amount of tension as the yarn 22 wound on the conveyer belts 17 becomes longer, the conveyer belts 17 cannot move smoothly. These conventional sample warpers are therefore disadvantageous because they require a considerable amount of power so as to drive the conveyer belts move stably.
[0010] In addition, when warping stretch yarns orderly in successive turns using the conventional sample warpers, the tension on the conveyer belts 17 would be very large during warping the stretch yarns orderly in successive turns, so that the attaching members 100 of the guide means G need to have enough strength to withstand such large amount of tension. Thus as the demand for flexible manufacturing is presumably on the rise in future, the above-described conventional sample warpers would be unable to use in the absence of some considerable reconstructions.
SUMMARY OF THE INVENTION
[0011] With the foregoing problems in view, it is an object of the present invention to provide a sample warper capable of winding a yarn with an effectively reduction of possible increase of the tension of yarns, which would unavoidably occur during conventional warping process, particularly orderly warping process in successive warp turns. Another object of the present invention is to provide a method of winding a yarn using the above-mentioned sample warper.
[0012] According to a first aspect of the present invention, there is provided a sample warper which comprises: a warper drum; a plurality of parallel conveyer belts mounted on a circumferential surface of the warper drum so as to extend in parallel to the axis of the warper drum and movable concurrently and longitudinally at a predetermined rate; at least one yarn introduction means rotatably mounted on a side surface of the warper drum for winding at least one yarn on the plural conveyer belts concurrently; a plurality of parallel lease rods longitudinally extending alongside of the warper drum for leasing the yarn; a creel supporting a plurality of bobbins from which yarns are paid out; and a plurality of short feed belts mounted on the circumferential surface of the warper drum at its end adjacent to the yarn introduction means so as to be movable in parallel to the plural conveyer belts, each of the short feed belts having an upper surface which is disposed radially outwardly of an imaginary cylindrical surface enclosing upper surfaces of the plural conveyer belts with respect to the axis of the warper drum; the yarn introduction means being operable to wind the yarns on the short feed belts so that the yarns are transferred from the short feed belts onto the plural conveyer belts for warping thereon.
[0013] As a preferred feature, the upper surfaces of the short feed belts extend radially outwardly of the imaginary cylindrical surface enclosing upper surfaces of the plural conveyer belts with respect to the axis of the warper drum. With this preferred feature, it is possible to reduce the whole tension of the yarns by transferring the yarns from the short feed belts onto the conveyer belts during the warping, thereby also reducing the tension (load) on the conveyer belts.
[0014] As another preferred feature, the short feed belts have flat surfaces, on which the yarns are to be wound, slanting down to their ends in a warping direction. The short feed belts are movable in synchronism with the movement of the conveyer belts in the same direction as that of the conveyer belts so that the yarns can be transferred onto the conveyer belts without disturbing the arrangement of turns of the yarns on the short feed belts.
[0015] As still another preferred feature, the short feed belts are also movable vertically so that the tension of the yarns can be adjustably reduced while transferring the yarns from the short feed belts onto the conveyer belts by varying the vertical positions of the short feed belts in accordance with the kind of yarns or characteristics of yarns.
[0016] As a further preferred feature, the sample warper of the present invention also has a plurality of guide means mounted on base ends of the short feed belts adjacent to the yarn introduction means for guiding the yarns from the yarn introduction means onto the short feed belts. This guide means includes a pivot disposed at the base end of the short feed belt, a guide member having a base end rotatably mounted on the pivot and a tip end normally biased so as to slant downwardly, a guide roller rotatably mounted on the tip end of the guide member, and a pair of parallel guide plates standing upright at both ends of the pivot, at least one of the two guide plates having such a shape as to guide the yarn.
[0017] As an additional preferred feature, a guide roller mounted on the tip end of the guide member is normally biased rotatably with respect to the pivot so as to slant downwardly toward the short feed belt. With this preferred feature, it is possible to slide the yarn received from the yarn introduction means down the slanting surface of the guide member, thereby leading the yarn onto the short feed belt for warping thereon. Further, because at least one of the two guide plates has such a shape as to guide the yarn, it is possible to guide the yarn effectively.
[0018] According to a second aspect of the present invention, there are provided four methods for winding yarns orderly in successive warp turns using the above-described sample warper according to the first aspect of the present invention. In the first and second methods according to the present invention, there are used the above-described sample warpers of the present invention in which the guide means are slidable in parallel to the short feed belts longitudinally thereof and yarns are orderly wound by the movement of the guide means.
[0019] The first method of the present invention for winding yarns orderly in successive warp turns using the above-described sample warper with a yarn introduction means winding a yarn in which the guide means are slidable in parallel to the short feed belts longitudinally thereof, comprises the steps of: moving the guide means in a warping direction by a distance P equal to or larger than a half of the thickness of the yarn for each revolution of the yarn introduction means; quickly moving the guide means back to the original start position by a distance Q which is equal to the product of the distance P and the preset number of multi-winding turns, i.e., a warping length when the number of revolutions of the yarn introduction means reaches the preset number of multi-winding turns; and moving the short feed belts and the plural conveyor belts in the warping direction by a distance R which is equal to a warping density, i.e., a warping width divided by the total number of winding turns. The above steps are repeated to completion of the total number of winding turns so that the yarns are wound orderly on the conveyor belts and the short feed belts.
[0020] The second method of the present invention for winding yarns orderly in successive warp turns using the above-described sample warper with a plurality of yarn introduction means winding a plurality of yarns concurrently in which the guide means are slidable in parallel to the short feed belts longitudinally thereof, comprises the steps of: moving the guide means in a warping direction by a distance P N equal to or larger than a half of the thickness of a bundle of the plural yarns for each revolution of the individual yarn introduction means; quickly moving the guide means back to the original start position by a distance Q N which is equal to the product of the distance P N and the preset number of multi-winding turns, i.e., a warping length when the number of revolutions of the individual yarn introduction means reach the preset number of multi-winding turns; and moving the short feed belts and the plural conveyor belts in the warping direction by a distance R N which is equal to the product of a distance R, which is a warping density, i.e., a warping width divided by the total number of winding turns, and the number of yarns N to be concurrently warped. The above steps are repeated to completion of the total number of winding turns so that the yarns are wound orderly on the conveyor belts and the short feed belts.
[0021] In the third and fourth methods according to the present invention, there are used the above-described sample warpers of the present invention in which the guide means are fixedly attached to the short feed belts and yarns are orderly wound by the movement of the short feed belts and the conveyor belts.
[0022] The third method of the present invention for winding yarns orderly in successive warp turns using the above-described sample warper with a yarn introduction means winding a yarn in which the guide means all fixedly attached to the short feed belts, comprises the steps of moving the plural short feed belts and the plural conveyor belts toward the guide means in a direction opposite to a warping direction by a distance P equal to or larger than a half of the thickness of the yarn for each revolution of the yarn introduction means; and quickly moving the short feed belts and the plural conveyor belts in the warping direction by a distance T which is the sum of a distance Q which is equal to the product of the distance P and the preset number of multi-winding turns, i.e., a warping length and the distance R which is equal to a warping density, i.e., a warping width divided by the total number of winding turns when the number of revolutions of the yarn introduction means reaches the preset number of multi-winding turns. The above steps are repeated to completion of the total number of winding turns so that the yarns are wound orderly on the conveyor belts and the short feed belts.
[0023] The fourth method of the present invention for winding yarns orderly in successive warp turns using the above-described sample warper with a plurality of yarn introduction means winding a plurality of yarns concurrently in which the guide means are fixedly attached to the short feed belts, comprises the steps of: moving the short feed belt and the plural conveyor belts toward the guide means in a direction opposite to a warping direction by a distance P N equal to or larger than a half of the thickness of a bundle of the plural yarns for each revolution of the individual yarn introduction means; and quickly moving the short feed belt and the plural conveyor belts in the warping direction by a distance T N which is the sum of a distance Q N which is equal to the product of the distance P N and the preset number of multi-winding turns, i.e., a warping length and a distance R N which is the product of a distance R which is a warping density, i.e., a warping width divided by the total number of winding turns, and the number of yarns to be concurrently warped N, when the number of revolutions of the individual yarn introduction means reach the preset number of the multi-winding turns. The above steps are repeated to completion of the total number of winding turns so that the yarns are wound orderly on the conveyor belts and the short feed belts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] [0024]FIG. 1 is a fragmentary perspective view of a principal portion of a sample warper according to the present invention;
[0025] [0025]FIG. 2 is a side view with parts broken away of an operation portion of a guide means of the sample warper of FIG. 1;
[0026] [0026]FIG. 3 is a cross-sectional view of the operation portion of the guide means;
[0027] [0027]FIG. 4 is a fragmentary side view illustrating the way how to guide a yarn in the guide means;
[0028] [0028]FIG. 5 is a fragmentary cross-sectional view illustrating the manner in which a yarn is wound on a short feed belt by the guide means;
[0029] [0029]FIG. 6 is a perspective view of a guide roll and a guide member;
[0030] [0030]FIG. 7 is an explanatory view of a wound state according to an embodiment of a first method of the present invention;
[0031] [0031]FIG. 8 is an explanatory view of a wound state according to an embodiment of a second method of the present invention;
[0032] [0032]FIG. 9 is a perspective view of one exemplary conventional sample warper;
[0033] [0033]FIG. 10 is a perspective view of another exemplary conventional sample warper;
[0034] [0034]FIG. 11 is a cross-sectional view illustrating the manner in which a yarn is wound on conveyer belts of the conventional sample warper; and
[0035] [0035]FIG. 12 is an explanatory view showing how to set the thickness (d) of a yarn (a) and the thicknesses (D) of bundles of a plurality of yarns (b) to
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. The present invention should by no means be limited to the illustrated embodiments, and various changes and modifications may be made in the present invention without departing from the technical concept of the present invention.
[0037] As shown in FIG. 1, a sample warper according to a first generic feature of the present invention a plurality of short feed belts 200 are mounted on the upper circumferential surface of a warper drum A at one base end adjacent to a yarn introduction means 6 (FIG. 4) centrally between a plurality of parallel conveyer belts 17 .
[0038] A driving pulley 206 and a guiding pulley 204 are rotatably supported on a support frame 201 attached to the base end of the warper drum A, which is adjacent to a yarn introduction means 6 (FIG. 4). The short feed belt 200 is wound on these two pulleys 204 , 206 so as to be movable thereround. A guide plate 202 of the support frame 201 is positioned in such a manner that an upper surface 200 b of the short feed belt 200 is disposed radially outwardly of an imaginary cylindrical surface enclosing the upper surfaces of the conveyer belts 17 with respect to the axis of the warper drum A and that the upper surface 200 b of the short feed belt 200 slants down in a warping direction.
[0039] The conveyer belts 17 is driven in response to the rotation of a driving pulley 210 , which is driven by a non-illustrated AC servo-motor, to move round a guiding pulley 208 . The driving pulley 206 of the short feed belt 200 is operatively connected with the driving pulley 210 of at least one of the conveyer belts 17 by a universal joint, a contractible driving shaft or the like so that the conveyer belts 17 are driven in synchronism with the short feed belt 200 by the non-illustrated AC servo-motor. Preferably, each of the conveyer belts 17 and the short feed belt 200 is a single-faced cogged belt having a flat surface, on which a yarn is to be wound, and a cogged surface engaged with a respective one of the driving pulleys 206 , 210 , which have the same number of cogs. It is also usable to provide separate driving motors which drive each of the conveyer belts 17 and the short feed belt 200 independently.
[0040] As shown in FIG. 4, the sample warper is further equipped with guide means G, mounted on a base end of short feed belt 200 adjacent to the yarn introduction means 6 , for guiding a yarn 22 from the yarn introduction means 6 . As shown in FIG. 3, the guide means G includes a pair of parallel guide plates 212 , 212 standing upright and confronting each other, a pivot 211 interconnecting the guide plates 212 , 212 , a guide member 214 , which has a base end pivotally mounted on the pivot 211 and a tip end normally biased by a spring 213 in such a manner that a yarn-slidable upper surface 214 a of the guide member 214 slants to the tip end downwardly toward the short feed belt 200 , and a guide roller 216 rotatably mounted on the tip end of the guide member 214 (FIG. 6).
[0041] The yarn 22 (or yarns) from the yarn introduction means 6 (or a plurality of yarn introduction means 6 a - 6 h ) slides down on the yarn-slidable surface 214 a of the guide roller 216 and is thereby brought onto an upper surface 200 a of the short feed belt 200 . Thus the yarn 22 is firstly wound on the upper surface 200 a of the base end of the short feed belt 200 without touching the upper surfaces 17 a of the conveyer belts 17 , as indicated by a solid line in FIG. 5. The yarn 22 is then transferred onto the slanting surface 200 b downwardly toward the tip end of the short feed belt 200 in response to the movement of the short feed belt 200 being synchronized with that of the conveyer belts 17 . When the yarn 22 reaches the same level as the upper surfaces 17 a of the conveyer belts 17 , the yarn 22 is delivered from the short feed belt 200 to the conveyer belts 17 and is thereby wound on the upper surfaces 17 a of the conveyer belts 17 , as indicated by a dash-and-two-dot line in FIG. 5.
[0042] Although a simple combination of the guide member 214 and the guide roller 216 would suffice to function as the guide means G, it is also effective that each of the guide plates 212 , 212 has a shape in conformity to the yarn-slidable surface 214 a of the guide means G.
[0043] As described above, simply by transferring (delivering) the yarn 22 from the short feed belt 200 , which is positioned radially outwardly of the warper drum A, onto the conveyer belts 17 , which are positioned radially inwardly of the warper drum A, it is possible to reduce the whole tension of the yarn 22 exerted on the warper drum A, thus facilitating the movement of the conveyer belts 17 . The support frame 201 for the short feed belt 200 is attached to a support post A 1 of the warper drum A as shown in FIG. 2. The support post A 1 of the warper drum A is divided into upper and lower portions, and the upper post portion A 2 is connected to the lower post portion A 3 so as to be vertically slidable with respect to the lower post portion A 3 . The upper post portion A 2 and the lower post portion A 3 of the support A 1 respectively have a hole H and a plurality of holes H 1 -H 3 so that the upper post portion A 2 can be fixed at a desired vertical position simply by fitting a bolt M through both of the hole H of the upper post portion A 2 and a desired one hole H 1 -H 3 of the lower post portion A 3 .
[0044] A second generic feature of the present invention is a method of winding a yarn 22 orderly in successive turns on the short feed belt 200 . According to first and second methods of the present invention, a yarn is wound orderly in successive warp turns by sliding the guide means G in parallel to the short feed belt 200 . The guide means G is mounted on the short feed belt 200 at its base end adjacent to the yarn introduction means so as to be slidable in parallel to the short feed belt 200 longitudinally thereof. As described above in connection with FIG. 3, the guide means G is rotatable about the pivot 211 interconnecting the confronting guide plates 212 , 212 , and is normally biased by the spring 213 so as to slant downwardly toward the short feed belt 200 . Further, the guide means G includes the guide member 214 , which has the upper surface (the yarn-slidable surface 214 a ) slanting downwardly to the tip end of the guide member 214 , and the guide roller 216 rotatably mounted on the tip end of the guide member 214 (as shown in FIG. 6).
[0045] As shown in FIG. 3, the two parallel guide plates 212 , 212 are respectively attached to a pair of parallel side members 110 , 110 of a folder plate 108 , which has a channel-like cross-sectional shape and is attached to a slide unit 116 . The slide unit 116 has a guide groove 114 slidable on a slide rail 118 so that the guide means G can slide.
[0046] The folder plate 108 has a rack gear 120 mounted on a lower surface of a base part of the folder plate 108 and engageable with a clutch gear 124 of a clutch shaft 122 . The clutch gear 124 is engaged and disengaged with the clutch shaft 122 (the clutch gear 124 ) in response to ON-OFF states of a electromagnetic clutch 126 . The clutch shaft 122 has a worm wheel 128 , which is attached to one end of the clutch shaft 122 and engaged with a worm 130 . The worm 130 has a sprocket wheel 129 which rotates around a worm pin 131 . The sprocket wheel 129 is operatively connected to the non-illustrated AC servo-motor. In FIG. 3, reference numeral 132 designates a bearing; 134 , a bearing case; 136 , a sprocket chain; and 138 , an idle wheel.
[0047] Further, as shown in FIG. 2, an end of the rack gear 120 is attached to one end of a connection pin 142 , the other end of the connection pin 142 being inserted through a hole 146 in a metal member 144 attached to the support frame 201 so that the connection pin 142 is horizontally slidable. A spring 148 is mounted round the connection pin 142 between the rack gear 120 and the metal member 144 so as to normally bias the rack gear 120 opposite to the direction of moving of the rack gear 120 in response to the rotation of the clutch gear 124 . Reference numeral 150 designates a stopper for defining a position of the rack gear 120 when the electromagnetic clutch 126 assumes an OFF state.
[0048] In an embodiment of the first method of the present invention in which, with the above-described guide means G, a yarn 22 is wound orderly in successive warp turns by a yarn introduction means 6 as shown in FIG. 9, a moving pitch or distance P of the guide means G is set in a controller (FIG. 7). The moving pitch P is equal to or larger than a half of the thickness of the warp yarn, preferably equal to or larger than the thickness of the warp yarn. Although there is no specific limitation on the upper limit of the pitch or distance P, it is preferably equal to or smaller than five times the thickness of the yarn. It is also preferable to previously store in the controller a table defining various thicknesses (for example, counts) of yarns and corresponding pitches P so that when a thickness of a warp yarn is inputted to the controller, the corresponding pitch P is automatically set in the controller.
[0049] As the warping begins, the guide means G is driven by the non-illustrated AC servo-motor to move in a warping direction by the pitch or distance P for each revolution of the yarn introduction means 6 . During that time, the electromagnetic clutch 126 is in engagement with the clutch gear 124 . The guide means G guides the yarn 22 from the yarn introduction means 6 to wind the yarn 22 on the upper surface 200 a of the short feed belt 200 while moving by the pitch or distance P for each revolution of the yarn introduction means 6 until the number of revolutions of the yarn introduction means 6 reaches the preset value (the preset number of multi-winding turns). When the number of revolutions of the yarn introduction means 6 reaches the preset number of multi-winding turns, i.e., a warping length, the electromagnetic clutch 126 is de-energized to assume an OFF state and the clutch gear 124 disengages with the clutch shaft 122 , so that the guide means G is quickly moved back to the original start position under the biasing force of the spring 148 . A distance Q by which the guide means G moves back is equal to the distance P x the preset number of multi-winding turns (FIG. 7).
[0050] At that time, the short feed belt 200 and the conveyer belts 17 are driven by the non-illustrated AC servo-motor to move in the warping direction by a warping density, namely, by a distance R=a warping width÷the total number of winding turns. It is also preferable to divide the distance R so that the short feed belt 200 and the conveyer belts 17 move by a divided distance for each revolution of the yarn introduction means 6 .
[0051] The operation of the guide means G and the short feed belt 200 will now be described with reference to FIG. 7, in which both of the moving pitch P and the distance R, which is a warping density=a warping width÷the total number of winding turns, are equal to the thickness of the warp yarn 22 . In FIG. 7, the guide means G first moves from its start position (leftside in FIG. 7) in the warping direction (rightwardly in FIG. 7) by the distance P for each revolution of the yarn introduction means while winding a yarn in order of 1 A- 2 A- 3 A- 4 A- 5 A- 6 A. When turns of winding (the number of revolutions of the yarn introduction means) reaches 6 , the electromagnetic clutch 126 is de-energized to assume an OFF state and the guide means G is quickly moved back to the original start position under the biasing force of the spring 148 . During that time, the short feed belt 200 moves in the warping direction (rightwardly in FIG. 7) by the distance R, i.e., a warping density=a warping width÷the total number of winding turns, so that a yarn 1 B is wound at the distance R from the center of the previous yarn 1 A. Then the electromagnetic clutch 126 is energized to assume an ON state and the guide means G moves again by the distance P for each revolution of the yarn introduction means while guiding a yarn B to thereby wind the yarn in the order of 2 B- 3 B- 4 B- 5 B- 6 B (FIG. 7). Likewise the following yarns 1 C, 1 D, . . . are successively wound to complete the orderly warping process.
[0052] In an embodiment of the second method of the present invention in which, with the above-described guide means G, a plurality of N warp yarns 22 (for example, 8 yarns as shown in FIG. 10) are concurrently wound orderly in successive warp turns using a plurality of yarn introduction means 6 a - 6 h shown in FIG. 10, a moving pitch or distance P N of the guide means G is set in the controller. The moving pitch P N is equal to or larger than a half of the thickness D of a bundle of the plural warp yarns, preferably equal to or larger than the thickness D of a bundle of the plural warp yarns. It is also preferable to previously store in the controller a table defining various thicknesses (for example, counts) of yarns, preset numbers of multi-winding turns and corresponding pitches P N so that when the thicknesses (for example, counts) of the warp yarns and the preset number of multi-winding turns are inputted to the controller, the corresponding pitch P N is automatically set in the controller. Although there is no specific limitation on the upper limit of the pitch or distance P N , it is preferably equal to or smaller than five times the thickness of the bundle of the plural yarns.
[0053] The above-mentioned thickness D of the bundle of the plural warp yarns is defined as shown in FIG. (b) to (p); that is, the plural warp yarns to be warped concurrently are imagined as states of bundles thereof and as the thickness of each bundle of various plural warp yarns to be warped concurrently, the following hypothetical value may be used; in case of 2 and 3 warp yarns, the thickness D of the bundle thereof is D=2 d (d: the thickness of a warp yarn); 4 yarns, D=2.6 d; 5 to 7 yarns, D=3 d; 8 yarns, D=3.5 d; 9 to 12 yarns, D=4 d, 13 and 14 yarns, D=4.4 d, 15 and 16 yarns, D=5 d.
[0054] As the warping begins, the guide means G is driven by the non-illustrated AC servo-motor to move by the distance P N in the warping direction for each revolution of the individual yarn introduction means 6 a - 6 h, the electromagnetic clutch 126 being engaged with the clutch gear 124 . The guide means G guides the yarns 22 from the yarn introduction means 6 a - 6 h to wind the yarns on the upper surface 200 a of the short feed belt 200 while moving by the pitch or distance P N for each revolution of the individual yarn introduction means 6 a - 6 h until the number of revolutions of the individual yarn introduction means 6 a - 6 h reaches the preset number of multi-winding turns. When the number of revolutions of the individual yarn introduction means 6 a - 6 h reaches the preset number of multi-winding turns, the electromagnetic clutch 126 is de-energized to assume an OFF state and the clutch gear 124 disengages from the clutch shaft 122 so that the guide means G is quickly moved back to the original start position under the biasing force of the spring 148 . A distance Q N by which the guide means G moves back is equal to the distance P N ×the preset number of multi-winding turns.
[0055] At that time, the short feed belt 200 and the conveyer belts 17 are driven by the non-illustrated AC servo-motor to move in the warping direction by a distance R N which is the product of a distance R, which is a warping density=a warping width÷the total number of winding turns, and N yarns to be concurrently warped. It is also preferable to divide the distance R N so that the short feed belt 200 and the conveyer belts 17 move by a divided distance for each revolution of the individual yarn introduction means 6 a - 6 h.
[0056] In the above-described warping process, the distance R or the distance R N is automatically calculated in the controller using input warping data including the warping width, the total number of winding turns and the number of yarns N to be concurrently warped, so that the short feed belt 200 and the conveyer belts 17 are automatically driven to move in accordance with the distance R or the distance R N .
[0057] According to third and fourth methods of the present invention, a yarn is wound orderly in successive warp turns by moving the short feed belt 200 and the conveyer belts 17 , without sliding the guide means G in parallel to the short feed belt 200 . As described above in connection with FIG. 3, the guide means G is rotatable about the pivot 211 interconnecting the confronting guide plates 212 , 212 and is normally biased by the spring 213 to slant downwardly toward the short feed belt 200 . Further, the guide means G includes the guide member 214 , which has an upper surface 214 a (on which a yarn is slidable) slanting to the tip end of the guide member 214 downwardly, and the guide roller 216 rotatably mounted on the tip end of the guide member 214 . And the guide plates 212 , 212 are fixed directly to the support frame 201 of the short feed belt 200 .
[0058] In an embodiment of the third method of the present invention in which a warp yarn 22 is wound orderly in successive warp turns using a sample warper including a yarn introduction means 6 shown in FIG. 9, a moving pitch or distance P of the short feed belt 200 and the conveyer belts 17 are set in a controller. The moving pitch or distance P is equal to or larger than a half of the thickness of the warp yarn, preferably equal to or larger than the thickness of the warp yarn. Although there is no specific limitation on the upper limit of the pitch or distance P, it is preferably equal to or smaller than five times the thickness of the yarns. It is also preferable to previously store in the controller a table defining various thicknesses (for example, counts) of yarns and corresponding pitches P so that when a thickness of the warp yarn is inputted to the controller, the corresponding pitch P is automatically set in the controller.
[0059] As the warping begins, the short feed belt 200 and the conveyer belts 17 move by a distance P toward the guide means G in the direction opposite to the warping direction for each revolution of the yarn introduction means 6 while guiding the yarn 22 from the guide means G to wind the yarn 22 on the upper surface 200 a of the short feed belt 200 until the number of revolutions of the yarn introduction means 6 reaches the preset number of multi-winding turns. When the number of revolutions of the yarn introduction means 6 reaches the preset value (the preset number of multi-winding turns), the short feed belt 200 and the conveyer belts 17 quickly moves in the warping direction by a distance T, which is the sum of a distance Q=the distance P×the preset number of multi-winding turns and a distance R, i.e., a warping density=a warping width÷the total number of winding turns.
[0060] The operation of the short feed belt 200 and the conveyer belts 17 will now be described with reference to FIG. 8, in which both of the moving pitch or distance P and the distance R, which is a warping density=a warping width÷the total number of winding turns, are equal to the thickness of the warp yarn 22 . In FIG. 8, the guide means G is located at such a leftside position (leftside in FIG. 8) as not to slide longitudinally of the short feed belt 200 , and is normally biased by the spring 213 to angularly move toward the short feed belt 200 about the pivot 211 . First of all, the short feed belt 200 and the conveyer belts 17 move toward the guide means G in the direction opposite to the warping direction by a distance P equal to or larger than a half of the thickness of the yarn for each revolution of the yarn introduction means while a yarn is wound by the guide member 214 and the guide roller 216 of the guide means G on the upper surface 200 a of the short feed belt 200 in order of 1 A- 2 A- 3 A- 4 A- 5 A- 6 A. When the number of multi-winding turns reaches 6 , the short feed belt 200 and the conveyer belts 17 quickly move in the warping direction by a distance T, which is the sum of a distance Q=the distance P×6 (the preset number of multi-winding turns) and a distance R, i.e., a warping density=a warping width÷the total number of winding turns, so that a yarn 1 B is wound at the distance R from the center of the previous yarn 1 A. Then the short feed belt 200 and the conveyer belts 17 move again by the distance P for each revolution of the yarn introduction means to wind a yarn B in order of 2 B- 3 B- 4 B- 5 B- 6 B as shown in FIG. 8. Likewise the following yarns 1 C, 1 D, . . . , 1 K are wound to complete the orderly winding in successive warp turns.
[0061] In an embodiment of the fourth method of the present invention in which a plurality of warp yarns 22 are concurrently wound orderly in successive warp turns using a plurality of yarn introduction means 6 a - 6 h, a moving pitch or distance P N of the short feed belt 200 and the conveyer belts 17 is set in the controller. The moving pitch or distance P is equal to or larger than a half of the thickness of a bundle of the plural warp yarns, preferably equal to or larger than the total size of the plural warp yarns. Although there is no specific limitation on the upper limit of the pitch or distance P N , it is preferably equal to or smaller than five times the thickness of bundle of the plural yarns. As the thickness of the bundle of the plural yarns, the hypothetical values shown in FIG. 12 may be used also in this method. It is also preferable to previously store in the controller a table defining various thicknesses (for example, counts) of yarns, preset numbers of multi-winding turns and corresponding pitches P N so that when the thickness (for example, count) of the warp yarns and the preset number of multi-winding turns are inputted to the controller, the corresponding pitch P N is automatically set in the controller.
[0062] As the warping begins, the short feed belt 200 and the conveyer belts 17 move by a distance P N toward the guide means G in the direction opposite to the warping direction for each revolution of the individual yarn introduction means 6 a - 6 h while guiding the yarns 22 from the guide means G to wind the yarns 22 on the upper surface 200 a of the short feed belt 200 until the number of revolutions of the yarn introduction means 6 a - 6 h reaches the preset number of multi-winding turns. When the number of revolutions of the individual yarn introduction means 6 a - 6 h reaches the preset value (the preset number of multi-winding turns), the short feed belt 200 and the conveyer belts 17 quickly moves in the warping direction by a distance T N , which is the sum of a distance Q N =distance P N ×the preset number of multi-winding turns and a distance R N which is the product of a distance R, which is a warping density=a warping width÷the total number of winding turns, and the number of yarns to be concurrently warped N.
[0063] In the above-described methods of the present invention for winding yarns in successive warp turns, when a first series of yarns has been wound on the warper drum, the leading yarn of the following series of yarns begins to be wound at a position ahead of the yarns of the first series.
[0064] According to the present invention, it is possible to effectively reduce the increase of tension of yarn, which would unavoidably occur during the conventional warping process, specifically during the conventional orderly warping process in successive warp turns.
[0065] Obviously, various minor changes and modifications of the present invention are possible in the light of the above teaching. It is therefore to be understood that within the scope of the appended claims the present invention may be practiced otherwise than as specifically described.
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In a sample warper, which includes a single yarn introduction means or a plurality of yarn introduction means for winding one or more yarns concurrently on a plurality of conveyer belts rotatably mounted on one side surface of a warper drum and movable on the warper drum at a predetermined rate of feed, a plurality of parallel lease rods arranged on a longitudinal side surface of the warper drum, and a creel on which a plurality of bobbins are supported, a plurality of short feed belts are mounted on the circumferential surface of the warper drum at its end adjacent to the yarn introduction means in such a way that the upper surface of the short feed belts are disposed radially outwardly of an imaginary cylindrical surface enclosing upper surfaces of the plural conveyer belts with respect to the axis of the warper drum. The yarn introduction means is operable to wind the yarns on the short feed belts so that the yarns are transferred from the short feed belts onto the plural conveyer belts for warping thereon.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of U.S. patent application Ser. No. 13/060,649, filed Feb. 24, 2011, which claims priority from International Application No. PCT/SE2008/000490, filed Aug. 29, 2008.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an implantable heart monitoring device, with which it is possible to monitor the heart condition. The invention also concerns a corresponding method.
[0004] 2. Description of the Prior Art
[0005] Several different devices for monitoring the performance of a heart are known. Often these devices are also able to deliver stimulation pulses to the heart. The devices are often able to sense the electrical activity in the heart. It is also known to determine an impedance value measured between different electrodes positioned in or at the heart. It is also known to sense other physiological parameters, such as pressure, oxygen level etc.
[0006] US 2001/0012953 A1 describes bi-ventricular pacing. An impedance may be measured between electrodes on the right and the left sides of the heart. The variation of the impedance with time is detected. The detected impedance variation may be used in order to synchronize the contraction of the ventricles.
[0007] US 2001/0021864 A1 describes different manners of using the proximal and distal electrodes of different leads in order to inject a current and to measure an impedance. The measured impedance value may be used in order to maximize the cardiac flow.
[0008] US 2007/0049835 A1 relates to an implantable cardioverter-defibrillator or pacemaker whose standard circuitry is used to trend a physiological cardiac parameter using intra-cardiac impedance measurements.
[0009] US 2007/0100249 A1 describes an implantable medical apparatus for detecting diastolic heart failure, DHF. The apparatus includes circuitry for determining, as the DHF parameter, the time duration of a predetermined phase of diastole.
[0010] US 2007/0055170 A1 describes a device for detecting the state of a heart on the basis of intracardial impedance measurement. The device has an impedance measuring unit as well as an analysis unit, which is connected to the impedance measuring unit and is implemented to derive a cardiac function parameter from a time curve of the impedance ascertained using the impedance measuring unit. The analysis unit derives a cardiac function parameter characterizing the behaviour of a heart during the diastole.
[0011] U.S. Pat. No. 6,314,323 describes a heart stimulator in which the cardiac output is determined by measuring the systolic pressure.
[0012] The article “Hemodynamic Effects of Tachycardia in Patients with Relaxation Abnormality Abnormal Stroke Volume Response as Overlooked Mechanism of Dyspnea Associated with Tachycardia in Diastolic Heart Failure” by Dae-Won Sohn et al., Journal of the American Society of Echocardiography, February 2007, pp. 171-176, describes a comparative study of two groups of individuals: healthy individuals and individuals with stable relaxation abnormality. The article describes how left ventricular pressure and stroke volume varies for the two groups when the heart is paced with 80 beats per minute and 120 beats per minute.
SUMMARY OF THE INVENTION
[0013] An object of the present invention is to provide an implantable heart monitoring device with which it is possible to detect or monitor the status of the heart of a patient who suffers from a heart failure, in particular a diastolic dysfunction. A further object is to provide such a device, which with quite simple means makes it possible to detect or monitor the status of the heart condition of a patient who suffers from such heart deficiency.
[0014] The above objects are achieved by an implantable heart monitoring device having at least one memory and a control circuit configured to communicate with a number of implanted electrode and/or sensor members adapted to be positioned in a heart or in relation to a heart of a living being such that the control circuit, by means of these members, is able to detect the heart rate of the living being and to derive information correlated to the stroke volume of said heart, wherein the control circuit is configured to carry out the following steps:
[0015] a) detect the heart rate,
[0016] b) derive said information correlated to the stroke volume at said detected heart rate, and
[0017] c) store the detected heart rate and the derived information correlated to the stroke volume in said memory,
[0000] wherein the control circuit is configured to automatically carry out steps a) to c) at a number of different occasions at different, naturally varying, heart rates, such that the memory contains information that indicates the stroke volume as a function of the heart rate.
[0018] The information concerning the stroke volume as a function of the heart rate constitutes important information about the status of the heart. In particular, when a patient suffers from a diastolic dysfunction, the stoke volume tends to decrease more with increasing heart rate than for a patent without such dysfunction. The more the stroke volume decreases with increasing heart rate, the worse is the dysfunction in question. Since according to the present invention, information concerning the stroke volume as a function of the heart rate is obtained, the device according to the invention provides important information concerning the status of the heart. Furthermore, the device carries out the mentioned steps automatically, which means that for example no physician needs to be present for carrying out the steps. The device does not have to have a complicated construction in order to provide the information. For example, an implantable heart stimulation device can with simple measures be constructed to constitute a device according to the invention.
[0019] It should be noted that with naturally varying heart rate is in this document meant that the heart rate is the heart rate of a heart that at the occasion in question is not paced at all by a heart stimulating device, or, if the heart is paced, then the pacing pulses are delivered in accordance with the intrinsic rate of the heart.
[0020] It should also be noted that as a measure of the heart rate, for example the duration of the heart beat can be used (since the duration of a heart beat is the inverse of the heart rate). The duration can be detected, for example as the RR-interval, i.e. the time between two R-waves. The heart rate may thus be determined for an individual heart beat.
[0021] According to an embodiment of the invention, the control circuit is configured to carry out the steps for at least three different heart rates such that the information that indicates the stroke volume as a function of the heart rate can be determined with a sufficiently high accuracy.
[0022] Since the control circuit is configured to carry out the steps for at least three different heart rates, the stored information concerning stroke volume as a function of the heart rate can be determined with a high accuracy. Preferably, the control circuit is configured to carry out the steps for more than three different heart rates, for example for at least 5 different heart rates. Thereby it can be determined with even higher accuracy how the stroke volume varies as a function of the heart rate. Consequently, very accurate information about the status of the heart can be obtained.
[0023] According to an embodiment, the control circuit is configured to carry out the steps for different heart rates, which differ from each other such that the highest heart rate is at least 10%, preferably at least 25%, higher than the lowest heart rate. Thereby, the stoke volume as a function of the heart rate can be determined for a relatively large variation of the heart rate, which means that a very good information concerning the status of the heart is obtained.
[0024] According to a further embodiment, the control circuit is configured to create a warning message if the obtained information that indicates the stroke volume as a function of the heart rate fulfils a predetermined criterion.
[0025] The predetermined criterion may for example be that the information that indicates the stroke volume as a function of the heart rate indicates that the stroke volume decreases when the heart rate increases. Another criterion may be that the information that indicates the stroke volume as a function of the heart rate indicates that the stroke volume decreases more than a predetermined amount when the heart rate increases.
[0026] With such a warning message, for example the patient in question or a physician can be alerted. The warning message may be any kind of warning message. The warning message may for example be stored in the memory. Such a warning message may for example be transferred in a wireless manner to an external device, located outside of the living being. Such a warning message may be communicated to the living being in which the device is implanted or to a physician.
[0027] According to a further embodiment, the control circuit is configured to, for a certain heart rate, derive the information correlated to the stroke volume during a plurality of heart beats, such that a more accurate information correlated to the stroke volume at the heart rate in question is obtained than if the information is derived only during one heart beat.
[0028] It should be noted that when it is said that the control circuit is configured to, for a certain heart rate, derive the information correlated to the stroke volume during a plurality of heart beats, this does not mean that the heart rate must be exactly the same for the number of heart beats. For example, the information correlated to the stroke volume for a certain heart rate may be derived for 10 different heart beats with heart rates varying between 72 and 75. From this procedure it is possible to determine for example an average measure of the stroke volume, and an average heart rate within the interval 72 to 75. Thereby a measure of the stroke volume at the heart rate in question is obtained. Hereby a more accurate information correlated to the stroke volume at the heart rate in question is obtained than if the information is derived only during one heart beat.
[0029] According to a further embodiment, the control circuit is configured such that the number of different occasions takes place within a first time period.
[0030] The time period may for example be less than 24 hours, preferable less than 1 hour, for example less than 20 minutes.
[0031] According to a further embodiment, the control circuit is configured such that the number of different occasions will also take place within at least one second time period, at a later time than the first time period, such that the memory comprises information that indicates the stroke volume as a function of the heart rate both within the first time period and within said second time period, wherein said memory contains information as to whether the indicated stroke volume as a function of the heart rate has changed between said first and second time periods.
[0032] The first and second time periods should thus not overlap with one another. The second time period may for example take place at least 1 day, or at least one week, after the first time period. By determining the stroke volume as a function of the heart rate during different time periods, it is possible to monitor how the heart condition has changed between these time periods.
[0033] According to a further embodiment, the control circuit is configured to create a warning message if the indicated stroke volume as a function of the heart rate has changed more than a predetermined amount between said first and second time periods. For example, a warning message may be created if the function determined in the second time period indicates that the diastolic dysfunction has become worse, for example indicated by the fact that the stroke volume decreases more with increasing heart rate than during the first time period.
[0034] The warning message may be any kind of warning message, for example as explained above.
[0035] According to a further embodiment, the device has a detector for detecting the physical activity of the living being, and the control circuit is configured to be able to determine the occasions when the steps are to be carried out in dependence on physical activity sensed by the detector for detecting the physical activity.
[0036] Since, the control circuit is configured to select said number of occasions in dependence on the physical activity sensed by said detector, it is possible to obtain the information that indicates the stroke volume as a function of the heart rate within a relatively short time. With the help of the sensed physical activity, it is thus possible to determine whether the physical activity of the living being changes, such that the heart rate is likely to change. It is thereby possible to obtain the information correlated to the stroke volume for different heart rates in a relatively short time. For example, each of the mentioned first and second time periods may be shorter than 20 minutes.
[0037] Alternatively, it is of course also possible for the device to directly monitor the heart rate of the living being and to select the different occasions when suitable, different heart rates are detected, such that the information that indicates the stroke volume as a function of the heart rate is obtained.
[0038] According to a further embodiment, the control circuit is configured to derive the information correlated to the stroke volume of said heart by carrying out an impedance measurement that indicates how the amount of blood in the left ventricle of the heart varies with time, which measurement thus creates a signal that varies with time, and thereby constitutes a curve that indicates how the amount of blood in the left ventricle of the heart varies with time.
[0039] Such an impedance measurement is an advantageous, and relatively simple, manner of determining the information that is correlated to the stroke volume.
[0040] According to a further embodiment, the control circuit is configured to derive the information correlated to the stroke volume either from the aforementioned curve, from a filtered such curve, from a template based on different such curves from different heart beats or from a template based on different filtered such curves from different heart beats.
[0041] The detected impedance curve may thus be filtered, for example in order to filter out artifacts and in order to make the curve smoother. A template can be created based on a measurement during a plurality of heart beats. The template is thus a representative curve based on measurements for a plurality of heart beats. The template may thus be a kind of average, or typical curve based on measurements for different heart beats.
[0042] According to a further embodiment, said information correlated to the stroke volume is derived by considering one or both of the following:
[0043] a) an area defined by the curve, filtered curve or template,
[0044] b) a peak-to-peak value of the curve, filtered curve or template.
[0045] In for example these manners, a good indication of the stroke volume can be obtained.
[0046] According to a further embodiment, the control circuit is configured to determine whether the contraction of the ventricle at the occasion in question belongs to a special category, and if this is the case, then the control circuit is either configured not to store the derived information in the memory, or to store the derived information separately in said memory such that the memory contains information that the derived information relates to the special category such that the stored information in the memory is distinguished from the information obtained when the contraction does not belong to the special category.
[0047] According to a further embodiment, the control circuit is configured to determine whether the contraction of the ventricle at the occasion in question belongs to any of a number of different special categories, and depending on to which special category the contraction belongs, the control circuit is either configured not to store the derived information in the memory, or to store the derived information separately in the memory, depending on the category, such the stored information in the memory for the different special categories can be distinguished from one another.
[0048] For example, the control circuit can be configured to be able to detect one or more of the following special categories (in addition to normal sinus rhythm):
[0049] a) whether the contraction of the ventricle at the occasion in question is a premature ventricular contraction,
[0050] b) whether the contraction of the ventricle at the occasion in question relates to atrial fibrillation,
[0051] c) whether the contraction of the ventricle at the occasion in question is a supraventricular extra-systole,
[0052] d) whether the contraction of the ventricle at the occasion in question is caused by left ventricular pacing,
[0053] e) whether the contraction of the ventricle at the occasion in question is caused by right ventricular pacing,
[0054] f) whether the contraction of the ventricle at the occasion in question is caused by biventricular pacing.
[0055] For different such special categories, the heart may behave differently, such that the mentioned information that indicates the stroke volume as a function of the heart rate may depend on the type (or category) of heart beat. For example, for heart beats that are premature ventricular contractions (PVCs), the mentioned information that indicates the stroke volume as a function of the heart rate may change more when the heart condition becomes worse than for heart beats that are not PVCs. Consequently, it is an advantage of the invention that the information that indicates the stroke volume as a function of the heart rate is stored separately for, for example, PVCs. The stored information based on PVC beats may thus be more sensitive to a change in the heart condition and will therefore be suitable to use in order to monitor a change in the heart condition.
[0056] Another aspect of the invention relates to a method of monitoring a heart of a living being with the help of an implantable heart monitoring device. The method includes the following steps:
[0057] a) detect the heart rate,
[0058] b) derive information correlated to the stroke volume of the heart at the detected heart rate, and
[0059] c) store the detected heart rate and the derived information correlated to the stroke volume,
[0000] wherein the method also includes the following steps:
[0060] carry out steps a) to c) at a number of different occasions at different, naturally varying, heart rates, such that information that indicates the stroke volume as a function of the heart rate is obtained.
[0061] Such a method provides advantages corresponding to those described above in connection with the device according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0062] FIG. 1 shows schematically an implantable heart monitoring device with leads and electrodes positioned in or in relation to a heart.
[0063] FIG. 2 shows schematically a control circuit and a memory which are comprised in the heart monitoring device.
[0064] FIG. 3 show a schematic example of measured impedance as a function of time.
[0065] FIG. 4 shows schematically examples of how the stroke volume may vary as a function of the heart rate for different heart conditions.
[0066] FIG. 5 is a schematic flow chart illustrating a method according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0067] FIG. 1 shows schematically an embodiment of an implantable heart monitoring device 10 according to the invention. The device 10 has a casing 12 . The device 10 also has a control circuit 14 , which controls the operation of the device 10 . The device 10 also includes a memory 15 connected to the control circuit 14 . Furthermore, the device 10 has an activity sensor 16 for sensing how physically active the living being that carries the device 10 is. The sensor 16 is connected to the control circuit 14 .
[0068] The device 10 has a connector portion 13 , via which the device 10 can be connected to different leads 20 , 30 , 40 . According to this embodiment, there are three leads 20 , 30 , 40 . However, the number of leads can also be more or less than three. The leads 20 , 30 , 40 are provided with electrode surfaces 21 , 22 , 31 , 32 , 41 , 42 , 43 . The electrode surfaces 21 , 31 , 41 are so-called tip electrodes, while the other electrode surfaces 22 , 32 , 42 , 43 are so-called ring electrodes.
[0069] The device 10 is a heart monitoring device. However, the device 10 may also have means for pacing a heart. Furthermore, the device may be designed to also function as a defibrillator. It should be noted that the device may have many more components and functions which are normal for such devices.
[0070] According to the present embodiment, the implantable heart monitoring device 10 is set up to be able to sense the electrical activity of the heart and to pace different heart chambers. In the shown embodiment, the lead 20 has been introduced into the right atrium RA such that the electrode surfaces 21 , 22 are positioned in this atrium. The lead 30 has been introduced into the heart such that the electrode surfaces 31 , 32 are positioned in the right ventricle RV. The electrode surfaces 21 , 22 can thus be used to sense and pace the right atrium RA and the electrode surfaces 31 , 32 can be used to sense and pace the right ventricle RV. LA represents the left atrium of the heart. According to this example, no electrodes are positioned to pace the left atrium LA.
[0071] The lead 40 has been introduced via the right atrium RA and the coronary sinus such that the electrode surfaces 41 , 42 , 43 are positioned in a vein next to the left ventricle LV. The different electrode surfaces 41 , 42 , 43 can thus be used to pace and sense the left ventricle LV in a manner known to a person skilled in the art. In this example, the lead 40 has three different electrode surfaces 41 , 42 , 43 which make it possible to choose which electrode surfaces are to be used for sensing and pacing.
[0072] It is also well-known to a person skilled in the art that different electrode surfaces can be used for injecting a current and for sensing a voltage in order to measure an impedance across at least a portion of the heart. Also the casing 12 can be used for this purpose.
[0073] FIG. 2 shows schematically in particular the control circuit 14 in some more detail. The control circuit 14 comprises a control portion 18 that controls the operation of the control circuit 14 . The control portion 18 is connected to the above mentioned memory 15 . Furthermore, as is known to a person skilled in the art, the control circuit 14 may comprise a sensing circuit 25 and a pacing circuit 27 , which circuits are adapted to be connected to the lead 20 in order to pace and sense the right atrium RA. Moreover, a sensing circuit 35 and a pacing circuit 37 are adapted to be connected to the lead 30 in order to sense and pace the right ventricle RV. Furthermore, a sensing circuit 45 and a pacing circuit 47 are adapted to be connected to the lead 40 in order to sense and pace the left ventricle LV. The different sensing and pacing circuits are of course also connected to the control portion 18 . The control circuit 14 may be designed such that it is possible to select which of the electrode surfaces 21 , 22 , 31 , 32 , 41 , 42 , 43 that are to be used. Of course, also the leads 20 , 30 may be provided with more or less than two electrode surfaces.
[0074] The control circuit 14 is configured to operate in time cycles corresponding to heart cycles. This is normal for an implantable heart monitoring or pacing device.
[0075] The control circuit 14 is also configured to communicate with a number of electrode surfaces 12 , 21 , 22 , 31 , 32 , 41 , 42 , 43 and to measure an impedance with the help of at least two such electrode surfaces. The impedance indicates the impedance across a portion of the heart that includes at least a part of the left ventricle LV. How to measure such an impedance is known to those skilled in the art, for example from some of the above-mentioned documents. For example, the control circuit 14 can be configured to inject a current between the electrode surfaces 31 and 41 and to measure a voltage between the electrode surfaces 32 , 42 . However, other combinations of electrode surfaces can be used for the impedance measurement. However, the control circuit 14 is preferably set up such that the variation of the measured impedance is related to the variation in the amount of blood in the left ventricle LV.
[0076] FIG. 3 shows schematically an example of how the measured impedance Z may vary with time t. This schematic curve in FIG. 3 is rather smooth. Such a curve can be obtained by filtering the measured impedance. The impedance is in this case measured across the left ventricle LV. The impedance has a low value at the point 51 when the left ventricle LV is filled with blood. The impedance increases thereafter until a maximum value 53 is obtained when the left ventricle LV contains a minimum amount of blood. Thereafter, the impedance decreases until a new minimum value 55 is obtained when the left ventricle LV is again filled with blood. The time t 1 between the minimum values 51 and 55 represents the duration of a heart beat. The heart rate is the inverse of this time t 1 . The heart rate may for example be determined by means of the intracardial electrogram detected by the implanted device.
[0077] From the curve shown in FIG. 3 information correlated to the stroke volume SV can be obtained. As a measure of the stroke volume, for example, the peak to peak value between the minimum 51 and the maximum 53 can be used. Another alternative is to use an area defined by the curve as a measure of the SV. The area can for example be defined as the area between the curve and a predetermined base line, which for example can be the Z value indicated as 0 in FIG. 3 . In this manner a value of the stroke volume SV for the heart rate in question can be determined.
[0078] In order to improve the measurement of the SV, it is possible to determine a curve like the one shown in FIG. 3 for different heart beats but with essentially the same heart rate. From such different curves, a template may be formed that represents an average of the measured curves for the different heart beats at the heart rate in question.
[0079] The control circuit 14 is configured to detect the heart rate and to derive the mentioned information correlated to the stroke volume at the detected heart rate. The control circuit 14 will store the detected heart rate and the corresponding value correlated to the SV in the memory 15 .
[0080] Furthermore, the control circuit 14 is configured to carry out these steps at a plurality of different heart rates, for example for at least five different heart rates. The highest heart rate may thereby be at least 25% higher than the lowest heart rate. The different heart rates should be naturally varying heart rates as defined above. By storing the information related to the SV for the different heart rates in the memory 15 , the memory 15 will comprise information that indicates the stroke volume as a function of the heart rate.
[0081] Such information is schematically illustrated in FIG. 4 . This Figure shows the determined stroke volume SV as a function of the heart rate HR for two different situations represented by the functions 57 and 59 . Each dot represents the determined stroke volume for a certain heart rate. The function 57 may for example have been determined for a certain patient within a first time period (for example within an hour a certain day). The function 59 may have been obtained for the same patient during a second time period, for example a month later. Each function 57 , 59 thus represents the status of the heart at the time that the function in question was determined. For the function 57 , the stroke volume does not decrease much when the heart rate increases. However, for the function 59 , the stroke volume decreases more when the heart rate increases. This is an indication of the fact that the diastolic function of the heart is worse for the function 59 than for the function 57 . The heart condition of the patient in question has thus become worse.
[0082] Instead of storing all the measurement values in the memory 15 , it is possible to only store information that indicates the heart condition at the time period in question. For example the slope of the function 57 and 59 , respectively, can be the stored value that represents the heart condition.
[0083] The control circuit 14 may be configured to create a warning message, for example if for a certain function the stroke volume SV decreases more than a predetermined amount with increasing heart rate HR (if the negative slope of the function is higher than a predefined value).
[0084] The control circuit 14 may be configured to determine the functions (like 57 and 59 ) during different time periods as exemplified above. The control circuit 14 may thereby be configured to create a warning message if the indicated stroke volume as a function of the heart rate has changed more than a predetermined amount between the different time periods. The warning message may for example be created if the heart condition has become worse. For example, since the heart condition represented by the function 59 is worse than the heart condition represented by the function 57 , this means that a warning message may be created in this case.
[0085] In order to determine the occasions when the control circuit 14 is to carry out the measurements in order to determine the stroke volume as a function of the heart rate, the detector 16 for detecting the physical activity of the patient in question may be used. For example, the control circuit 14 may detect that the patient is physically active such that the heart rate is likely to change. Thereby the measurement steps can be carried out for the different heart rates such that a function as described above can be determined within a relatively short time period.
[0086] Preferably, the control circuit 14 is configured to determine the kind of heart beat that is involved when the stroke volume at the heart rate in question is determined. The control circuit 14 can thereby be configured to categorize the contraction of the ventricle in different categories depending on the kind of contraction. The contraction may for example be categorized as a normal sinus rhythm, as a premature ventricular contraction, as a contraction occurring during atrial fibrillation, as a supraventricular extra-systole or as a contraction caused by pacing (left ventricular pacing, right ventricular pacing or biventricular pacing). The control circuit 14 can thereby be configured to store the derived information regarding the stroke volume at the heart rate in question separately in the memory 15 for the different categories of heart contractions. Thereby a function like the ones represented in FIG. 4 can be determined separately for the different categories of heart beats.
[0087] FIG. 5 shows a schematic flow chart illustrating a method according to the invention. At the same time FIG. 5 illustrates how the device 10 according to the invention can be set up to operate.
[0088] First it is determined when to carry out the measurement with the help of the device 10 . For example, it can be programmed into the device 10 that the measurements in question are to be carried out once a week.
[0089] Next, an electrode configuration for carrying out the impedance measurement is determined. This can be programmed into the device in advance, or the device 10 can automatically select an appropriate electrode configuration for the measurement. For example, as indicated above, the measurement can be carried out by injecting a current between the electrode surfaces 31 and 41 and by measuring a voltage between the electrode surfaces 32 and 42 .
[0090] Next, with the help of the detector 16 , the physical activity of the patient is detected in order to determine if it is appropriate to carry out a measurement. Alternatively, the exact moments for carrying out the measurements may be determined in other manners. For example, the heart rate may be detected and if the heart rate is suitable to carry out the measurement, a measurement may be carried out.
[0091] Thereafter the impedance is thus measured during a heart beat at a certain heart rate. Preferably, the impedance curve is determined for a plurality (for example at least five) of heart beats at a certain heart rate. A template may thus be created. This template constitutes a representative curve for the measured impedance during a heart beat at the heart rate in question. The determined impedance curve, or the corresponding value representing stroke volume, is stored together with the heart rate.
[0092] As mentioned above, the stored information can be stored separately for different categories, depending on the kind of heart contraction. The different heart contractions that are used to create a template for the category in question should thus be of the same kind.
[0093] The same procedure is carried out for different heart rates until sufficient information is obtained in order to determine the stroke volume as a function of the heart rate. The stroke volume as a function of the heart rate, or a corresponding value thereof, is stored. The stored information is preferably stored separately for the different categories of heart contractions.
[0094] A warning message may be created if the information concerning the stroke volume as a function of the heart rate (for a certain category) fulfils a predetermined criterion. The criterion may for example be that the stroke volume decreases more than a predetermined amount when the heart rate increases.
[0095] The procedure described above is repeated at a later occasion, for example a week later. Thereby new information is obtained that indicates the stroke volume as a function of the heart rate. A warning message may then for example be created if the heart condition has become worse.
[0096] The warning message may for example be stored in the memory 15 in order to be communicated to a device external of the patient. The warning message may for example be communicated to a physician. Of course, not only the warning message but also other stored information may be communicated to an external device.
[0097] Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted heron all changes and modifications as reasonably and properly come within the scope of their contribution to the art.
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In an implantable heart monitoring device and method, particularly for monitoring diastolic dysfunction, a control circuit (a) detects the heart rate, (b) derives information correlated to the stroke volume of the heart at the detected heart rate, and (c) stores the detected heart rate and the derived information correlated to the stroke volume in a memory. The control circuit automatically implements (a), (b) and (c) at a number of different occasions for a number of different, naturally varying heart rates, so that the memory contains information indicating the stroke volume as a function of the heart rate.
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This application is a continuation of application Ser. No. 09/932,758 filed Aug. 16, 2001, now U.S. Pat. No. 6,570,345 the disclosure of each of which is incorporated in its entirety herein by reference.
FIELD OF THE INVENTION
This invention relates to constant current regulators, and more specifically to a high-power regulator controlled by a programmable logic for airport lighting applications.
BACKGROUND OF THE INVENTION
Approach lights for airport runways typically include sets of high-wattage lamps connected in series in a lighting loop. In order to maintain a uniform intensity throughout the loop regardless of supply voltage variations, and to allow selected changes of intensity to cope with various weather and natural light conditions, the lighting loop has to be supplied with an adjustable constant current that is unaffected by supply voltage variations or other electrical disturbances.
In addition, airport lighting is subject to strict FAA regulations which require, for example, minimization of switching harmonics and minimization of inductive loading of the power supply. Switching harmonics are undesirable both as a reflection into the power supply, and in the lighting loop. In the latter, the skin effect from high power harmonics can require the use of heavier copper cables (which can be quite long in airport applications), and the radiation of harmonics from the lighting loop can interfere with sensitive communication systems such as instrument landing systems.
The individual lamps of the loop are typically fed from the loop through isolation transformers. If a lamp burns out, the isolation transformer primary winding acts as an inductor and puts a substantial inductive load on the circuit. For that reason, a shorting device is mounted across the secondary of the isolation transformer. When the lamp fails (i.e. opens up), the shorting device is activated to keep the integrity of the loop intact.
With conventional analog control circuitry, control of an airport lighting constant current regulator is feasible but is not very flexible or efficient. It is therefore desirable to give the regulator a maximum of flexibility, e.g. automatic power reduction on power-up, power-down and in error conditions.
Another problem of the prior art is that regulators exceeding about 30 kW power capacity usually required oil cooling, which was expensive and environmentally undesirable. Also, a regulator adaptable to a wide range of power outputs generally required switchable taps on the main transformer windings that required resetting the transformer when changing the load.
SUMMARY OF THE INVENTION
The present invention solves the problems of the prior art by providing a constant current regulator using an air-cooled ferroresonant transformer that maintains a good power factor and efficiency over the entire 30 kW to 50 kW output power range without requiring any tap switching, in conjunction with a control system using a programmable logic to track circuit conditions and user interfaces, and to take appropriate control actions in response thereto.
Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent.
These and other aspects of the present invention are set forth in the following detailed description and accompanying claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the regulator system of this invention;
FIG. 2 is an equivalent circuit diagram of the ferroresonant transformer used in this invention;
FIG. 3 is a block diagram of the transformer control circuit; and
FIG. 4 is a block diagram showing relevant data inputs and outputs of the programmable logic used in the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates the basic circuitry of the inventive regulator. Power (typically 480 VAC) is applied to the power input 10 . Input voltage sensor 12 and input current sensor 14 monitor the input power and supply error signals 16 , 18 to the current control 20 if input voltage or input current are outside a predetermined safe range. The input power is applied through an electromagnetic interference (EMI) filter 22 to the primary winding 24 of ferroresonant transformer 26 , the details of which are discussed below.
A first secondary winding 28 powers the lighting loop 30 . The loop 30 is equipped with a loop voltage sensor 32 which, together with the loop current sensor 36 , provides an indication of the power input to the lighting loop 30 . The loop current sensor 36 senses the actual loop current and provides a signal 34 representative thereof to the current control 20 for control purposes.
The primary windings 38 a through 38 n of a plurality of isolation transformers 40 a - 40 n are connected in series in the loop 30 . The secondaries of the isolation transformers 40 a - 40 n drive the individual lamps 42 a - 42 n , respectively, of the lighting array. Because the isolation transformer primaries 38 a - 38 n are connected in series, the same current flows through all of them, and the brightnesses of the lamps 42 a - 42 n are therefore identical at the level selected by brightness selector 43 .
A pair of parallel-connected second secondary windings 44 a , 44 b (shown separately for conformance with is FIG. 2) drive a resonant capacitor 46 . As described below, the capacitor 46 is so dimensioned as to resonate at the 60 Hz line frequency with the leakage inductance of the transformer 26 , for a reason discussed below.
A third secondary winding 48 on transformer 26 is switched into and out of the circuit at a 60 or 120 Hz rate by an SCR switch 50 for a purpose described below. A snubber 52 is connected between the control line 54 and the switch 50 , more specifically across the gate/cathode connections of the dual SCRs that make up the switch 50 . This provides an interface between the gate trigger circuitry of the current control 20 and the gates/cathodes of the switch SCRs, as well as transient protection for the switch 50 .
FIG. 2 shows in more detail the equivalent circuit of the ferroresonant transformer 26 .
The principle of the ferroresonant transformer 26 is that the leakage inductances 56 a and 56 b resonate with the capacitors 46 a , 46 b , respectively, at 60 Hz. At resonance, the transformer 26 transfers power to the lighting loop 30 with maximum efficiency through windings 24 e and 28 (in the equivalent circuit of FIG. 2, the windings 24 a , 24 b , 24 c , 24 d and 24 e are all functional sections of a primary winding that drives the secondary windings 28 , 44 a , 44 b and 48 ).
The inductances 56 a , 56 b , 58 and 60 cooperate to keep high frequency harmonics out of the AC input and field wiring to reduce the need for heavy wiring and to prevent interference with airport avionics. The resonant filtering action of the ferroresonant transformer 26 provides a very low harmonic distortion, so that the output waveform is almost purely sinusoidal. The resonant filtering also provides maximum noise immunity and complete isolation between the input and output circuitry.
When inductance is added to the circuit by lamp inductance 58 and control inductance 60 , the transformer 26 becomes less resonant, and the gain of the transformer network, i.e. its ability to transfer power into the lighting loop 30 , is reduced. By closing switch 50 in FIG. 2 during a selected portion of each cycle or half-cycle of the oscillation of the resonant circuit, the gain of the transformer 26 can thus be adjusted.
The manner in which this adjustment is made is shown in FIG. 3 . In that figure, the inputs to the current control 20 are the voltage across capacitor 46 , the actual loop current signal voltage 34 , and the desired loop current signal voltage generated by the brightness selector 43 .
The voltage across capacitor 46 , which is a 60 Hz sine wave, is transmitted through isolation transformer 62 to a filter 64 which removes any spurious frequency components and puts out a clean 60 Hz sine wave 66 . This sine wave is applied to a zero crossing detector 68 which puts out a positive-crossing pulse 70 on rail 72 , and a negative-crossing pulse 74 on rail 76 . The pulses 70 and 74 provide a timing reference to a programmable logic 78 which controls the SCR switch 50 in synchronism with the oscillations of the resonant circuit of transformer 26 .
The actual loop current signal 34 is applied through summing resistor 80 to the subtractive input of an integrator 82 , and the loop current reference signal 83 generated by the brightness selector 43 is applied to the same input through summing resistor 84 . As long as the actual loop current is equal to the selected loop current reference, the current signals 34 and 83 (which are of opposite polarity) cancel each other out, and the continuously variable output of integrator 82 stays at a steady error voltage 87 which is applied to the negative input of comparator 88 . The positive input of comparator 88 is a sawtooth generator 90 that resets at each zero crossing of the 60 Hz signal 66 . When the level of the sawtooth wave equals the error signal 87 , the comparator 88 puts out a logic “1” signal that causes the programmable logic device 78 to trigger the switch 50 closed until the next zero crossing of the signal 66 . The zero crossing of signal 66 opens the switch 50 and resets the sawtooth generator 90 .
When the brightness selector setting is changed; an extra inductive load due to lamp burnout changes the resonance of transformer 26 ; or some other imbalance between signals 34 and 83 occurs, the integrator 82 translates that imbalance into an increase or decrease in the error signal 86 so as to change the portion of the sawtooth wave during which the SCR switch 50 is closed. The purpose of diode 91 is to prevent overdriving the comparator 88 by limiting the negative change of voltage 86 to a single diode drop.
FIG. 5 diagrammatically illustrates the programmable logic device 78 . Programming software within the device 78 is designed by conventional methods to scan the inputs 92 and, based thereon, carry out, i.e., the following functions: 1) following a power-up or shut-down command, the device 78 , by forcing the switch closed, reduces brightness to a selectable low level for a short, selectable time before carrying out the command, so as to prevent large switching transients; 2) selectable out-of-range levels of circuit parameters such as AC input power voltage and lighting loop current are made to cause selectable responses such as alarms, power-downs or shut-downs; and 3) data for front-panel indicators and monitors is generated to show real-time status and operating parameters of the equipment. Because the inventive regulator maintains a constant output current even if the loop shorts out, the logic device reacts only to no-loop-current (i.e. open-loop) and overcurrent conditions. The latter may occur momentarily, for example, when the AC supply is toggled between commercial power and generator power.
The efficient, low heat-generating construction of the ferroresonant transformer 26 makes it possible to smoothly power any substantially resistive load from 30 to 50 kW or more without the use of switchable taps or oil cooling. That ability, coupled with the wide-ranging ability of the digital programmable logic device 78 to adjust the regulator's performance characteristics by software changes, results in a versatile and economic airport lighting control.
It should be understood that the exemplary constant current regulator for airport lighting described herein and shown in the drawings represents only a presently preferred embodiment of the invention. Indeed, various modifications and additions may be made to such embodiment without departing from the spirit and scope of the invention. Thus, other modifications and additions may be obvious to those skilled in the art and may be implemented to adapt the present invention for use in a variety of different applications.
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A constant-current regulator for high-powered airport lighting loops combined a ferroresonant transformer and a digital programmable logic device to provide a versatile, software-modifiable current control for power transfer throughout a range of about 30 kW to 50 kW with uniformly good power factor and low harmonics without switching winding taps, and without requiring oil cooling.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to electrical connector devices. More particularly, the invention relates to indoor electrical outlets and indoor electrical outlet covers.
2. Description of Relevant Art
Electrical service in buildings, particularly in homes, offices, and schools, is typically provided at least in part through electrical wall outlets. Devices needing electrical current for operation or use have electrical cords ending in electrical plugs for connection to an electrical wall outlet. Once the plug is inserted into the wall outlet, electrical current can flow (or does flow if the wall outlet has electrical current flowing into it) to the cord for activating the device needing current.
Most typically, when a plug with a cord is connected to an electrical wall outlet, the plug and cord extend several inches from the wall outlet before the cord curves to a parallel posture with respect to the wall. As a consequence, furniture or other items positioned adjacent to the wall must be positioned sufficiently away from the wall outlet to accommodate the plug and cord connection to the wall outlet and also to accommodate someone's hand and often times arm in reaching behind the furniture to insert the plug into the wall outlet. Such positioning wastes space in the room and is generally unattractive.
Moreover, typically and commonly used electrical wall outlets are themselves generally unattractive and are known to pose a potential safety hazard for infants and children. Blank cover plates and individual non-conductive plugs are commonly used to prevent children from inserting objects into wall outlet receptacles and getting shocked and injured thereby, but such plates and plugs then prevent use of the outlets.
There is presently a need in the art for electrical wall outlets and electrical wall outlet covers that overcome the shortcomings presented above.
SUMMARY OF THE INVENTION
The present invention provides an indoor electrical wall outlet cover that solves the problems associated with indoor outlet covers. The present invention provides an indoor electrical wall outlet cover that is thin enough to avoid adding bulk to the outlet and thus enables furniture to effectively be positioned against the wall or at least as close as the baseboard on the wall, that also effectively covers the outlet so as to act as a safety device for a child that may seek to touch or access the outlet receptacles, and that still allows ready access to the electrical connection that the outlet affords. Moreover, the outlet cover is aesthetically pleasing—it is unobtrusive and calls less attention to itself than does the outlet without the cover of the invention. This is because the outlet cover, at least in one embodiment, is essentially or substantially blank, hides the receptacles of the outlet completely, and results in only one cord extending from the outlet and that extension is in a manner where the cord lies against the wall or along the wall or less than about an inch from the wall, at least when proximate the outlet.
The present invention effects these advantages by providing a thin cover, preferably smooth on the outside, that just extends fully over the surface of an electrical outlet having at least two receptacles, without protruding significantly therefrom and that has an electrical connection component on the backside that plugs into a receptacle of the outlet for making electrical contact and an non-electrical connection component also on the backside that plugs into another receptacle of the outlet and together with the electrical connection component of the invention, hold the cover in place over the outlet. The electrical connection component of the cover of the invention has an electrical cord attached thereto that extends downward from the electrical connection component out of the cover and falls generally flush with the wall to the floor, where the cord lies against the wall or along the wall or less than about an inch from the wall, at least when proximate the outlet, and then lies along the floor or other desired surface, ending in one or more electrical receptacles. The electrical connection component in one embodiment has electrical pins bent at approximately ninety degree angle so that the connection of that component in the receptacle does not add bulk or cause the cover to extend significantly beyond the outer surface of the electrical wall outlet.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be better understood by referring to the following detailed description of preferred embodiments and the drawings referenced therein, in which:
FIG. 1 is a front perspective view (for illustration and not drawn to scale) of one embodiment of the apparatus of the invention, as shown in place on an electrical outlet as it might typically be used.
FIG. 2 is an enlarged front side perspective view of the embodiment of the apparatus of the invention of FIG. 1 , just before it is placed over a typical electrical outlet on a wall (for illustration and not drawn to scale).
FIG. 3 is a back perspective view of the embodiment of the apparatus of the invention of FIG. 1 .
FIG. 4 is a side view of the embodiment of the apparatus of the invention of FIG. 1 .
FIG. 5 is a view of the inside of the back plate of the embodiment of the apparatus of the invention of FIG. 1 showing the electrical connection component having electrical pins bent at a ninety degree angle with respect to each of the two legs of each electrical pin.
FIG. 6 is a top view of the back plate of the embodiment of the apparatus of FIG. 1 showing the electrical pins and the ground pin as they extend out of the back plate.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention provides for the indoor use of electricity through an indoor, thin, blank electrical wall outlet cover in a manner that fully conceals the underlying electrical wall outlet and one or more electrical plugs directly connected to that outlet and an electrical cord extending from said electrical plug(s), past, through, or out of the cover, preferably at the base of the cover, and ending a desired distance away with at least one receptacle at the electrical cord's distal end. This apparatus of the invention is particularly advantageous as a safety device that permits functional use of a standard or typical indoor electrical wall outlet while fully concealing the wall outlet and particularly concealing and shielding the openings or receptacles in the outlet from access by children. The apparatus of the invention obtains such safety advantage while being so thin as to avoid adding any significant bulk to the wall outlet, thereby enabling a user to position furniture in front of or adjacent to the outlet and essentially flush with, i.e., less than about an inch away from, the wall on which the outlet is located, or at least as close to the wall as any baseboard on the wall permits, and thereby providing another advantage of the invention.
The present invention eliminates the traditional manner of connecting a visible electrical plug to a visible indoor electrical wall outlet in order to consume electricity through such electrical wall outlet. Interior electrical wall outlets are points in an interior space of a building such as a home where electrical current can be run to power electrical devices such as appliances and electronics. The most common such outlets are 15-amp (and sometimes 20-amp) duplex receptacles, which are designed to accept standard plugs for most small appliances, electronics such as televisions and home theater systems as well as cellular phones and portable computing devices such as laptops and tablet computers, and lamps. The invention has utility with any such interior electrical wall outlets and the term “typical (or standard) indoor electrical wall outlet” herein is understood to refer to such outlets as well as similar outlets that have more receptacles.
Referring to FIG. 1 , one embodiment of the apparatus 10 of the invention is shown in place over a typical indoor electrical wall outlet 11 (not shown in FIG. 1 but shown in FIG. 2 ) on an interior wall 23 . FIG. 2 , showing the cover 15 of apparatus 10 just before placement over the electrical wall outlet 11 , and FIG. 4 , showing the side of cover 15 , indicate the thin, low profile of cover 15 , particularly comprising frontplate component 12 mounted on backplate component 14 . FIGS. 1 and 2 are drawn to illustrate features of the invention and are not drawn to scale. That is, cover 15 is drawn larger with respect to the remainder of the apparatus 10 and with respect to the wall outlet 11 than is actually contemplated to in fact occur with the embodiments of the invention as will be more fully explained below. As used herein, the term “frontplate” with respect to the apparatus of the invention and particularly cover 15 means the faceplate or faceplate component of cover 15 , and not the common faceplate of the wall outlet. The apparatus of the invention is used to hide the wall outlet 11 but no change or adjustment in the wall outlet 11 needs to be made. That is, the common faceplate of the wall outlet 11 does not need to be removed. To avoid any confusion between the common faceplate of a wall outlet and the faceplate of the cover of the apparatus of the invention, the faceplate component of the cover 15 of the apparatus 10 of the invention will be called herein the “frontplate.” The frontplate and backplate components of the invention are made of material that satisfies NEMA Standards or standards for UL safety certification. Such materials are characterized by resistance to chemicals, heat and impact, and typical applications include use in appliance housings and electronic and electrical assemblies. These materials include various plastics, including acrylonitrile butadiene styrene or ABS and polyvinyl chloride or PVC.
The maximum distance between the backplate component 14 and the frontplate component 12 is approximately the height or thickness of the electrical cord 16 connected to or attached to the backplate component 14 , and this distance is only in the main body or central portion of the cover 15 , as the outer or perimeter edges of the components 12 and 14 are proximate one another and touch or essentially touch, with the perimeter edge of backplate component 14 fitting inside the outer edge of frontplate component 12 , as shown in FIG. 3 . The frontplate component 12 is sized to align and position over and preferably curve slightly around or up to the perimeter edge of the backplate component 14 for a tight fit—preferably tight enough to require no adhesive or screws to hold the components 12 and 14 together.
An integral aspect of this embodiment of the apparatus 10 of the invention is the electrical pins 18 and 28 and ground wire 19 , which are bent at approximately a ninety degree angle with respect to the backplate component 14 and fastened to the backplate component 14 , as shown in FIG. 5 . In this aspect, the height of the horizontal portion of each electrical pin 18 and 28 and the ground wire 19 is approximately less or the same height (or thickness) as the electrical cord 16 , which is attached to the electrical pins 18 and 28 and to ground wire 19 . Electrical cord 16 is also optionally attached to the backplate component 14 . A benefit of the electrical pins 18 and 28 and the ground wire 19 being bent at a ninety degree angle is that the depth of the cover 15 , measured by the distance between the wall 23 when the cover 15 is inserted in the underlying electrical wall outlet 11 and the front face of the cover or the outer or exterior surface of the frontplate component 12 , resting on top of the backplate 14 which in turn is resting on top of the underlying electrical wall outlet 11 , is less than the depth of a typical electrical plug connected in a traditional manner to the electrical wall outlet 11 , which is a typical electrical wall outlet, and cover 15 may have less depth than the depth of baseboard molding 21 at the base of the wall 23 . For example, a typical electrical plug is at least about an inch wide and when on an electrical cord and inserted into an electrical wall outlet, such as electrical wall outlet 11 , such plug and adjacent cord typically protrude or extend outwardly from the outlet a distance of more than an inch and often protrude as much as about two inches to even four inches. In contrast, the cover 15 of the apparatus 10 of the invention when placed over the electrical wall outlet 11 extends outward from the outlet no more than the thickness of the cover 15 . Cover 15 is as thin as the thickness of the combination of the frontplate component 12 mounted on the backplate component 14 and the electrical pins 18 and 28 , the ground wire 19 , and electrical cord 16 in between the components 12 and 14 . This combined thickness, or thinness, is less than about an inch and also is less than the thickness of a typical baseboard at the base of a wall in preferred embodiments.
As shown in FIG. 6 , electrical pin 18 is associated with plug prong 20 (neutral), electrical pin 28 (hot) is associated with plug prong 30 , and ground wire 19 is associated with ground plug prong 22 (ground). These plug prongs 20 , 30 and 22 are like typical electrical plug prongs used in typical wall outlets.
The conductive electrical pins 18 and 28 and ground wire 19 and corresponding plug prongs 20 , 30 and 22 comprise a configuration of one of about fifteen electrical plug types currently in use, as categorized by the U.S. Department of Commerce International Trade Administration. An integral aspect of this embodiment is connection of the electrical pins 18 and 28 , through respective plug prongs 20 and 30 , to the respective contacts 31 and 33 in a receptacle of wall outlet 11 as shown in FIG. 2 of the underlying interior electrical wall outlet 11 without any visible electrical pins 18 or 28 or visible ground wire 19 , which are all fully concealed under the backplate component 14 and the frontplate component 12 mounted to the backplate component 14 . Electrical pins 18 and 28 and ground wire 19 comprise the proximal end of electrical cord 16 of the apparatus 10 of the invention. The opposite or distal end of the electrical cord 16 has or comprises one or more electrical receptacles or sockets 26 for receiving one or more third-party electrical plugs (not shown) for utility, namely electricity consumption. Such third-party electrical plugs are not part of the invention, but rather are associated with various household and personal devices that require electricity for operation or for battery charging for operation.
The distal end of electrical cord 16 can be any shape and have any receptacle or socket configuration that is useful for containing or providing electrical receptacles, such as for nonlimiting example a power strip 29 as shown in FIG. 1 or a power cube (not shown), but in most embodiments will be configured to have more than one receptacle 26 . In one embodiment, such receptacles or sockets in the distal end of electrical cord 16 are all standard receptacles. In another embodiment, such receptacles or sockets in the distal end of electrical cord 16 comprise at least one interchangeable plug for use in the North America, South America, Europe, Asia, and Australia. In still another embodiment, such receptacles in the distal end of electrical cord 16 also include or comprise one or more USB ports. In another alternative embodiment, electrical cord 16 simply ends in a single receptacle plug. In still another alternative embodiment, power strip 29 comprises a retracting mechanism (not shown) so that cord 16 can be pulled to the exact length needed or desired between the wall outlet 11 and the receptacle(s) 26 at the distal end of electrical cord 16 for utility. Such retracting mechanism would include a catch and release mechanism to hold the cord at the desired length, and to hold the cord tightly at that length so the cord appears neat and unobtrusive along the wall and floor or any other surface it is directed to extend or lay. The exact desired length of electrical cord 16 will vary depending on the intended us of the invention. Generally, the length is sufficient for electrical cord 16 to extend from backplate 14 or cover 15 and be manually guided around any adjacent or nearby furniture and positioned so that the distal end of the electrical cord 16 of apparatus 10 of the invention is conveniently and safely located for use of the receptacle(s) 26 or socket(s) in said distal end of cord 16 . In one embodiment, for example, the distance the cord will extend is selected from a range of about three feet to about thirty feet, although many different variations would work, and longer cords could be used. The length of the cord is generally limited by practical reasons—one does not want a cord so long that excess cord gets in the way of furniture and becomes unsightly or a tripping hazard. As stated above, the present invention advantageously enables furniture to be positioned flush against the wall and in front of a wall outlet covered by the cover 15 of the apparatus of the invention.
As indicated above, through use of electrical cord 16 , the apparatus of the present invention advantageously eliminates the need to attach an electrical plug of an electrical device directly to the contact openings or receptacles of an electrical wall outlet for use of the outlet. Further, in this aspect, the present invention has an aesthetic benefit with embodiments whereby multiple functional receptacles or sockets are at the distal end of the electrical cord over conventional attachment of multiple cords directly to the outlet. That is a single cord of the apparatus of the invention in such embodiments has the same utility or functionality with respect to providing electricity to multiple third party devices as would be typical with multiple cords extending directly from the outlet in traditional or conventional use without the invention.
The apparatus of the invention also advantageously can be used with any standard, conventional, or typical indoor electrical wall outlet, without having to make any adjustments or physical changes in the wall outlet. Screws are not needed for attachment of the cover of the apparatus of the invention to the wall outlet for covering the wall outlet and the wall outlet does not need to be replaced with a frontplate particularly designed to fit with the cover of the apparatus of the invention. Rather, the apparatus of the invention and particularly the cover 15 of the apparatus 10 of the invention is held in place over the wall outlet 11 by insertion of prongs 20 , 30 , and 22 , and at least two non-conductive plug prongs 32 of the apparatus 10 as shown in FIG. 3 , in respective receptacles of the wall outlet 11 , as indicated in FIGS. 2 and 4 , which otherwise would normally be available to receive or allow insertion of two electrical plugs.
Wall outlet 11 , as indicated in FIG. 2 , is a standard, conventional, or typical indoor electrical wall outlet, which is believed to be commonly called a one-gang electrical wall outlet, and which has two receptacles or sockets, an upper and a lower receptacle or socket, in vertical alignment with each other. Thus, the apparatus of the invention 10 attaches to such a standard wall outlet 11 having two receptacles or sockets by insertion of the plug prongs 30 , 20 , and 22 of the apparatus of the invention 10 into the upper wall outlet receptacle and by insertion of non-conductive plug prongs 32 of the invention 10 into the lower wall outlet receptacle. In one embodiment, the apparatus of the invention could be similarly used with a standard one-gang electrical wall outlet having two receptacles or sockets aligned in a horizontal position. In such case, electrical cord 16 would extend from one side of the cover 15 , rather than the base of the cover 15 as shown in FIG. 1 , or could be adapted (i.e., moved) to extend from the base of the cover in the horizontal position.
The apparatus of the present invention can also be readily adapted for standard, conventional, or typical multi-gang outlets, such as for nonlimiting example, double or triple wall outlets. Such outlets tend to simply be double, triple, quadruple, or other multiple versions of a single gang outlet and thus respectively have four, six, eight, or other multiple receptacles or sockets typically aligned in pairs. Thus the apparatus of the invention would be expanded to accommodate four, six, eight, or other multiple pairs of electrical plugs and non-conductive plugs for insertion into the corresponding outlet receptacles or sockets. For another example, in one such alternative embodiment, the multi-gang electrical outlet is sized to support up to about sixteen receptacles or sockets, normally allowing attachment or insertion into the multi-gang electrical outlet as many as sixteen electrical plugs, or an apparatus of the invention with eight electrical plugs and eight non-conductive plugs.
In such alternative embodiments of the invention not shown for use in multi-gang outlets, the backplate component of the cover of the apparatus of the invention is sized to align and position over such standard indoor multi-gang electrical wall outlet. The frontplate component is sized to align and position over and curve slightly around the perimeter edge of the backplate component for a tight fit as described above that preferably requires no adhesive or screws to stay in place. To add to the aesthetics of the cover 15 of the invention, in one embodiment at least the front or exterior of the frontplate is painted or is covered in wallpaper.
In another embodiment of the apparatus of the invention, having an alternative electrical connection to that discussed above and illustrated in FIG. 5 , the electrical pins are fastened to the backplate component and connected to an insulated conductive connector which in turn is connected to a wire forming a part of the electrical cord at the proximal end and one or more outlets at the distal or opposite end of the electrical cord to which one or more third-party electrical plugs are connected for electricity consumption.
The present invention has been illustrated with electrical plugs and receptacles having shapes that are commonly used in the United States of America. However, it is known that different shaped electrical plug prongs and receptacles are used in different countries and the present invention may readily be adapted for those different shapes.
While preferred embodiments of the present disclosure have been described, it should be understood that other various changes, adaptations and modifications can be made therein without departing from the spirit of the invention(s) and the scope of the appended claims. The scope of the present disclosure should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents. Furthermore, it should be understood that the appended claims do not necessarily comprise the broadest scope of the invention(s) which the applicant is entitled to claim, or the only manner(s) in which the invention(s) may be claimed, or that all recited features are necessary.
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An indoor electrical wall outlet cover permitting functional use of an electrical wall outlet while fully concealing the plug contact openings of the outlet. The cover has a functional electrical plug that inserts into the wall outlet and is connected to an extended electrical cord having at its distal end one or more functional electrical receptacles for indirect use of the wall outlet. In one embodiment, the cover is essentially featureless in outward appearance, and when positioned over the wall outlet, the cover fully hides the wall outlet from view, including the perimeter dimension of the wall outlet. The functional electrical plug has electrical connection pins that are bent at a angle enabling the cover to function without extending any significant degree outward of the wall outlet, so that furniture may be positioned effectively flush against the wall in front of the covered wall outlet.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 09/649,188, filed Aug. 28, 2000, now U.S. Pat. No. 6,573,729 and entitled SYSTEMS AND METHODS FOR IMPEDANCE SYNTHESIS, which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. The Field of the Invention
The present invention relates to impedance synthesis. More specifically, the present invention relates to the synthesis of user specified source or load impedances using digital processing.
2. The Relevant Technology
Ordinarily, circuits are designed such that the load impedance is much greater than the impedance of the source that is driving the load. Otherwise, the load impedance may have an adverse effect on the source voltage by causing the output voltage of the source to drop. This undesirable result is related to the finite value of the source impedance. Transmission lines, however, are an exception to this general rule. In the case of transmission lines, it is desirable that the load impedance match the impedance of the transmission line for several reasons.
In a basic form, a transmission line is two or more parallel conductors which connect a source to a load. The load presents an impedance to the transmission line and the transmission line presents a characteristic impedance, which is usually a combination of the source impedance and the impedance of the transmission line, to the load. When the transmission line is attached to a load having an impedance equal to the characteristic impedance of the transmission line, the power in the signal transferred to the load is maximized and the signal is not reflected back to the source. These benefits are important for many different applications. If the power transfer is not maximized, it is possible that the connecting device will be unable to properly interpret the signal. If signal reflections are present on the transmission line, then the signal becomes difficult to demodulate and additional circuitry is required to remove the reflections or echoes.
One common example of a transmission line which is used for moderate frequencies is a parallel conductor, which is frequently used in telephone networks. The parallel conductors of a telephone network are often referred to as the tip and ring. Thus, the tip and ring comprise the transmission line and the load impedance may be embodied as a telephone, modem or other device capable of connecting to the telephone network.
The telephone network specifies the characteristic impedance of the transmission line which must be matched by a connecting device in order to fully transfer power and avoid signal reflection. However, the impedance specified by the telephone network is usually only an approximation of the actual impedance, which results from such variables as: the variations in the length of the transmission lines to the connecting device from the central office; various wiring topologies within an intermediary installation such as a series of parallel transmission lines within a business or other structure; and intrinsic variations in the transmission lines themselves. The actual characteristic impedance presented by the telephone network is difficult to precisely match and is usually only approximated.
With regard to telephone networks, the problem is complicated by the fact that telephone networks across the world specify different characteristic impedances. In this situation, it is feasible that a device functioning perfectly in one telephone network will encounter difficulty in another telephone network. Because telephones, modems and other telephonic devices are being used world wide, it is necessary to enable a telephonic device to function in any telephone network environment.
While many devices are capable of operating in different networks, the result is not always satisfactory. One solution is to characterize the impedances of the various telephone networks into groups and physically place more than one impedance in the device. The appropriate impedance is then selected using appropriate switching technologies such as relays or field effect transistor (FET) switches. This method has several disadvantages. First, control circuitry must be employed to control the relays and switches, which is not a trivial task because of the high voltages which may be present on many transmission lines. Because of the high voltages, the components used for the switches and relays can be large and expensive and must be rated to withstand the high voltages which can be present on a transmission line.
While placing multiple impedances on a device to permit a device to function in more network, the physical impedances physically placed on the device are designed to approximate, rather than match, the characteristic impedances that may be encountered in different telephone networks, which results in less than optimal power being transferred to the load as well as signal reflections back to the signal source. Also, many devices, such as modems, have limited printed circuit board surface area on which to place these additional circuit elements and a relatively large number of discrete circuit components such as resistors, operational amplifiers and capacitors can require significant surface area. Further, the combined tolerances of the passive and active circuit components may result in a large variance from the desired impedance.
The problem of properly terminating a transmission line has also been addressed in terms of impedance synthesis. However, these attempts have involved the use of discrete circuit components such as resistors and operational amplifiers. These methods, however, are limited to synthesizing real or resistive impedances. Recursive digital filters have also been utilized, but this approach introduces incidental shunting impedances, whose effects must be eliminated. In addition, digital filters are capable of introducing unacceptable delays.
BRIEF SUMMARY OF THE INVENTION
While many devices are capable of operating in different networks, the result is not always satisfactory. One solution is to characterize the impedances of the various telephone networks into groups and physically place more than one impedance in the device. The appropriate impedance is then selected using appropriate switching technologies such as relays or field effect transistor (FET) switches. This method has several disadvantages. First, control circuitry must be employed to control the relays and switches, which is not a trivial task because of the high voltages which may be present on many transmission lines. Because of the high voltages, the components used for the switches and relays can be large and expensive and must be rated to withstand the high voltages which can be present on a transmission line.
While placing multiple impedances on a device to permit a device to function in more network, the physical impedances physically placed on the device are designed to approximate, rather than match, the characteristic impedances that may be encountered in different telephone networks, which results in less than optimal power being transferred to the load as well as signal reflections back to the signal source. Also, many devices, such as modems, have limited printed circuit board surface area on which to place these additional circuit elements and a relatively large number of discrete circuit components such as resistors, operational amplifiers and capacitors can require significant surface area. Further, the combined tolerances of the passive and active circuit components may result in a large variance from the desired impedance.
The problem of properly terminating a transmission line has also been addressed in terms of impedance synthesis. However, these attempts have involved the use of discrete circuit components such as resistors and operational amplifiers. These methods, however, are limited to synthesizing real or resistive impedances. Recursive digital filters have also been utilized, but this approach introduces incidental shunting impedances, whose effects must be eliminated. In addition, digital filters are capable of introducing unacceptable delays.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the manner in which the above-recited and other advantages and objects of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawing depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
FIG. 1 is a block diagram illustrating a source impedance connected to a load impedance by a transmission line;
FIG. 2 is a block diagram depicting a modem connected to a telephone network in terms of a load impedance and a source impedance;
FIG. 3 is a schematic diagram illustrating the synthesis of a load impedance;
FIG. 4 is a schematic diagram illustrating the synthesis of a source impedance; and
FIG. 5 is a flowchart of a method for synthesizing an impedance.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Impedances are a fundamental part of electronics. The analysis and design of circuits requires knowledge of impedance and its effects. For example, telephone networks have an associated characteristic impedance and any device that connects to that telephone network must be designed to match the prescribed impedance at particular frequencies. These requirements are imposed in part to protect the telephone network from the potentially adverse effects of a poorly designed connecting device. More importantly, these requirements ensure that a connecting device is able to maximize power transfer and avoid signal reflection.
Typically, impedance is created by some combination of resistors, capacitors, and inductors. However, these elements have inherent tolerance levels that can affect the actual value of the impedance being designed. Additionally, these circuit elements are relatively large and occupy precious surface area on such devices as modem and network interface cards that could be used for other purposes. These and other limitations are overcome by the present invention which provides for the synthesis of an impedance which essentially eliminates the need for physical circuit elements in some circumstances. The present invention is capable of synthesizing both load and source impedances and can be adapted to synthesize an impedance wherever an impedance is needed.
The invention is described below by using diagrams to illustrate either the structure or processing of embodiments used to implement the systems and methods of the present invention. Using the diagrams in this manner to present the invention should not be construed as limiting of its scope. The present invention contemplates both methods and systems for digitally synthesizing an impedance. The embodiments of the present invention may comprise a special purpose or general-purpose computer including various computer hardware, as discussed in greater detail below.
Embodiments within the scope of the present invention also include computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media, which can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or a combination of hardwired or wireless) to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such a connection is properly termed a computer-readable medium. Combinations of the above should also be included within the scope of computer-readable media. Computer-executable instructions comprise, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions.
The present invention is described with reference to a transmission line because a transmission line typically connects a load impedance with a source impedance. It is understood, however, that the systems and methods of the present invention are not limited to applications requiring transmission lines. FIG. 1 generally illustrates the impedances associates with a transmission line. Source 20 typically generates a signal which is transmitted to load 30 . Source 20 also receives signals generated and transmitted by load 30 . Source 20 is represented as having a signal generator 24 and a source impedance 22 . Load 30 illustrates a load impedance 32 . Load 30 is connected to source 20 by transmission line 40 and as previously indicated, signal reflection and power transfer are two concerns associated with transmission lines. These and other problems may be avoided by having load impedance 32 substantially match source impedance 22 . From the point of view of load 30 , source impedance 22 includes the inherent impedance of transmission line 40 .
FIG. 2 is a practical implementation of the generalized case illustrated in FIG. 1 . Modem 36 is an example of a connecting device, which is capable of connecting with central office 26 . Central office 26 is part of a telephone network, which specifies the impedances that must be met by connecting devices in certain states. For example, the impedance needed to terminate a ringing signal, which has a relatively low frequency, produced by central office 26 is often different than the impedance required to properly terminate signals such as voice signals, which have higher frequencies. In this example, central office 26 is equivalent to source 20 of FIG. 1 . Modem 36 is representative of load 30 and is designed to present a prescribed load impedance 32 to central office 26 .
FIG. 3 is an exemplary schematic of one embodiment for synthesizing a load impedance. Load impedance 32 is effectively connected to transmission line 40 via terminals 41 and 42 . Load impedance 32 , looking towards transmission line 40 sees characteristic impedance 64 . Transmission line 40 looking towards terminals 41 and 42 sees apparent load impedance 62 . Apparent load impedance 62 is composed of two impedance components, the actual load impedance of the attached load and the synthesized load impedance. When combined the actual load impedance and the synthesized load impedance form load impedance 32 . The preferred load impedance 32 is created or synthesized by impedance synthesizer 58 such that apparent load impedance 62 substantially matches characteristic impedance 64 , which is equivalent to a source impedance.
Impedance synthesizer circuit 58 comprises a current source 60 and impedance synthesis circuitry 50 . The current I L 61 produced by current source 60 is dependent on output voltage V o 63 output by impedance synthesis circuitry 50 . Impedance synthesis circuitry 50 further includes a analog to digital converter (ADC) 54 , a generator 52 , and a digital to analog converter (DAC) 56 . In order for circuit 58 to generate or synthesize an impedance that substantially matches characteristic impedance 64 , current 61 generated by current source 60 must have a value equal to the voltage present on transmission line divided by characteristic impedance 64 . Impedance synthesis circuitry 50 is an example of impedance synthesis means.
Characteristic impedance 64 , or the source impedance is usually a known or prescribed value. Thus the value of the load impedance to be synthesized is also known in most instances. The process of synthesizing load impedance 32 begins by determining the line voltage V L 65 , which is the voltage across terminals 41 and 42 in this example. ADC 54 receives the voltage present on each terminal 41 and 42 in order to determine and digitize line voltage 65 . Generator 52 receives the digitized line voltage and produces a numeric output that is related to the prescribed load impedance. The output voltage of generator 52 is converted to its equivalent by voltage DAC 56 and connected to current source 60 . Generator 52 produces an output voltage that causes current source 60 to generate a current having a value of line voltage 65 divided by load impedance 32 . Circuit 58 synthesizes a load impedance having a value equal to line voltage 65 divided by current 61 , which is substantially equal to characteristic impedance 64 .
In a preferred embodiment, generator 52 is capable of generating or synthesizing more than one impedance. Generator 52 may be embodied as a digital processor, micro-controller, programmable logic gate array, logic circuitry, state machine, or in software. Impedance synthesis circuitry. 50 may also be implemented as an ASIC, which frequently incorporates, along with generator 52 , ADC and DAC interfaces as integrated subsystems. As a result, the only other component needed to synthesize an impedance across two terminals is an external voltage to current converter or current source. In another embodiment, the current source or voltage to current converter can also be internal to the ASIC as long as the maximum voltage across terminals 41 and 42 does not exceed the safe operating voltage of the ASIC. ASIC is another example of impedance synthesis means.
FIG. 4 is a schematic diagram of one embodiment of circuitry for synthesizing a source impedance, as opposed to a load impedance. Several similarities exist between the synthesis of both load impedances and source impedances. For instance, the generation or synthesis of a source impedance also utilizes DAC 56 and ADC 54 . Generator 77 is similar to generator 52 in FIG. 3, with the essential difference being that the controlling factor is the value of the source impedance instead of the load impedance. DAC 56 , ADC 54 , and generator 77 may be contained in an ASIC, as described with respect to FIG. 3 .
The synthesis of source impedance (Z s ) 22 is synthesized or created by determining the voltage across source impedance 22 , which is: V−V L =V s . The current I s through source impedance 22 is equal to V s divided by Z s . Voltage V L 72 is subtracted from voltage V 24 using inverter 74 and adder 75 . As a result of this combination by adder 75 , the voltage sampled and digitized by ADC 54 is the voltage across source impedance 22 or V s . This voltage V s is scaled and processed by generator 77 to generate an output substantially equal to V s divided by Z s . DAC 56 transforms this output voltage into its analog equivalent, which is fed to a voltage to current converter, or current source 60 . It is assumed that V dc node 70 is maintained at an appropriately higher potential than voltage V L 72 .
Current source 60 is capable of generating a current in either direction in order to accommodate negative impedance elements. The synthesis of negative impedance elements is effectively accomplished by changing the algebraic signs of the terms that are used in generator 77 . Also, inductive elements can be gyrated to capacitive elements and vice versa.
FIG. 5 illustrates an exemplary flowchart of the steps required to synthesize an impedance. In step 100 , a voltage is sensed or measured. In many instances, the voltage being measured appears across the terminals of a transmission line, but the impedance may occur in other locations. In a preferred embodiment, the impedance to be synthesized will appear across the terminals whose voltage is being measured. The chronological gap between the sampling of the voltage and the application of the synthesized impedance should be minimized to obtain the most effective results. In step 102 , the measured or sensed voltage is received at an ADC and digitized.
After the sensed or measured voltage has been digitized, a digital processor in step 104 processes the digitized signal. The function of the processor is to output a value or voltage that is related to the sensed voltage and the impedance that is being synthesized. This step is accomplished because the value of the impedance being synthesized is known and the relevant voltage has been measured. Typically, the output voltage of the digital processor has a value equal to the ratio of the sensed voltage divided by the desired impedance. One exemplary execution of this step scales and processes the digitized samples in conjunction with values that correspond to a prescribed load impedance thereby generating a output equal to the originally measured voltage divided by the prescribed impedance.
In step 106 the output generated by the digital processor is supplied to a DAC, where it is converted to its analog equivalent. The analog output voltage is operably connected to and drives a voltage to current converter in step 108 to generate a certain current. The value of the current is substantially equal to the sensed voltage divided by the desired impedance. Because the impedance is being synthesized across two terminals whose voltage is known and because the current being generated at the voltage to current converter is also known, the impedance between the terminals is, by Ohm's law, equal to the ratio of the sensed voltage divided the generated current, which is equal to the desired impedance. To maintain accuracy of synthesized impedance, the device continues to monitor the voltage level by returning to step 100 after step 108 . This feedback loop allows the device to continuously measure and make various adjustments.
Accordingly, this impedance synthesis method is not limited to voltage adjustment and may be applied to the adjustment of many different circuit characteristics, such as voltage, current, or impedance depending on the application. Thereby enabling the attached load circuit to match the source with the least signal degradation. Facilitating this matching allows the source and load to interact in an optimal power transfer manner.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
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The present invention synthesizes a prescribed impedance. The impedance is synthesized by generating a current having a value substantially equal to a voltage divided by a prescribed impedance. Sensing the line voltage and converting that sensed line voltage to its digital equivalent accomplish this first step. The digital line voltage is processed by a factor related to the prescribed impedance to produce an output voltage that has a value substantially equal to the sensed voltage divided by the prescribed impedance. The output voltage controls a voltage to current converter that generates the appropriate current across the points or terminals where the line voltage was measured. Thus, the prescribed impedance is generated across these points or terminals because the line voltage divided by the generated current is substantially equal to the prescribed impedance.
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BACKGROUND OF THE INVENTION
A. Field of the Invention
This invention relates to a latch for locking well tools in a well flow conductor. The latch has radially expandable locking keys and also has a valve controlled pressure equalizing fluid passage.
B. The Prior Art
U.S. Pat. No. 3,208,531 to Tamplen issued Sept. 28, 1965 and titled "INSERTING TOOL FOR LOCATING AND ANCHORING A DEVICE IN TUBING" discloses a latch for locking tools in a well flow conductor which has radially expandable locking keys.
The use of an equalizing sub, having a valve controlled pressure equalizing fluid passageway, in conjunction with a latch having radially expandable locking keys, is disclosed on pages 3957 through 3969 of the "COMPOSITE CATALOG OF OIL FIELD EQUIPMENT AND SERVICES", 1974-1975 edition.
These latches and equalizing subs are satisfactory when the well is equipped for service with wire line equipment. However, they could not be used if the well is to be serviced with pumpdown equipment. The length of the disclosed latches is such that the latches are too long to be able to negotiate the bend or curved tubing through which pumpdown equipment must pass. The disclosed equalizing subs simply add length to the latch.
Pumpdown latches have been devised. It has been the practice to position the valved equalizing passage utilized with a pumpdown latch in a separate sub. The sub extends below the latch and is connected thereto by a swivel joint. (See page 4077 of the "COMPOSITE CATALOG OF OIL FIELD EQUIPMENT AND SERVICES" 1974-1975 edition). Such a conventional pumpdown latch and equalizing sub arrangement has several limitations. First, the swivel joint cannot withstand a high pressure differential. Therefore, the pressure range of the latch is limited to the pressure differential that may be withstood by the swivel joint. Second, opening the equalizing passage in the equalizing sub prior to retrieval of the latch is difficult. With the equalizing sub below the latch, a prong must be inserted through the latch bore to move the valve within the equalizing sub. The prong is slightly longer than the length of the latch and is joined to a pumpdown retrieving tool with a swivel joint. To properly align such a prong so that it may pass through the bore of a latch and actuate a valve in an equalizing sub is exceedingly difficult.
OBJECTS OF THE INVENTION
An object of this invention is to provide a well latch which overcomes the above noted deficiencies in present pumpdown latches.
Another object of this invention is to provide a short well latch, incorporating a valve-controlled equalizing passage, so that the latch may make up one short section of a pumpdown tool train.
Another object of this invention is to provide a well latch having a valve-controlled equalizing passage wherein the valve can be moved to a position opening the equalizing passage without the use of a long prong.
Another object of this invention is to provide a well latch having radially expandable locking keys and having a back-up expander for maintaining the keys in expanded position wherein the distance that the expander undergoes to back up the keys is less than presently required.
Another object of this invention is to provide a well latch having a valve-controlled equalizing passage, radially expandable locking keys, and a back-up key expander which is releasably maintained in either one of its two operative positions.
Another object of this invention is to provide a well latch having a valve-controlled equalizing passage wherein the valve is held in a position opening the passage until the latch is landed and locked in a well flow conductor.
Another object of this invention is to provide a well latch incorporating a valve-controlled equalizing passage and including a fishing neck, wherein after the latch is landed and locked in a well flow conductor with the valve closing the equalizing passage, the fishing neck cannot be engaged by a fishing tool until the valve has opened the equalizing passage.
Another object of this invention is to provide a well latch incorporating a valve-controlled equalizing passage and including a load ring for improved force transmission from the fishing tool to the latch housing during retrieval of the latch.
These and other objects and features of advantage of this invention will be apparent from the drawings, the detailed description, and the appended claims.
DESCRIPTION OF THE DRAWINGS
In the drawings wherein like numerals indicate like parts and wherein illustrative embodiments of this invention are shown:
FIG. 1 is a quarter-sectional view of one embodiment of the latch;
FIG. 2 is a sectional view of the latch of FIG. 1 together with its running tool illustrating the latch being located in a landing nipple of a well conduit;
FIG. 3 is a sectional view of the latch and running tool of FIG. 2 illustrating the locking of the latch in the landing nipple;
FIG. 4 is a sectional view of the latch and running tool of FIG. 2 with the the latch locked in the landing nipple and running tool being retrieved from the well;
FIG. 5 is a sectional view of the latch of FIG. 1 locked in the landing nipple prior to engagement by a retrieving tool;
FIG. 6 is a sectional view of the latch after engagement by the retrieving tool;
FIG. 7 is a sectional view of an alternate embodiment of a latch and its alternate running tool being located in the well conduit with the latch in the landing nipple;
FIG. 8 is a sectional view similar to FIG. 3 illustrating the locking of this alternate embodiment of the latch by the running tool in the landing nipple; and
FIG. 9 is a sectional view of this alternate latch embodiment locked in the landing nipple and the alternate running tool being retrieved from the well.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A well flow conductor often includes one or more landing nipples in which a latch will be landed and locked. Either the latch or the latch running tool will have means for locating the latch with respect to the landing nipple. After the latch is located, the running tool is manipulated to lock the latch within the landing nipple. Various well equipment may be associated with the latch. The well equipment may control flow through the well flow conductor or perform other operations in the well while locked in the well flow conductor by the latch.
If a pressure differential will exist across the latch and the locked well equipment, a valved equalizing fluid passage is preferably provided. The equalizing passage generally is open during running of the latch and well equipment and is closed upon landing and locking the latch in the landing nipple. Prior to retrieval of the latch and well equipment, the equalizing passage is opened. Pressures are thereby equalized across the latch. Thereafter, the latch and associated well equipment may be safely unlocked and removed from the well flow conductor under control conditions without being moved quickly in the well due to shut in well pressure below the latch.
The latch of this invention is designed for use in pumpdown installations. Pumpdown equipment enters the well through either a loop or curved portion of tubing. A pumpdown tool train is therefore comprised of a plurality of short tool sections. Each tool section is short enough to be able to negotiate the loop or curved tubing and is connected to the other tool sections by universal joints. The latch of this invention is short and makes up one section of the pumpdown tool train. The latch itself includes the valve controlled pressure equalizing passage. The expander, which backs up the radially expandable locking keys of the latch, has a shortened distance of travel between its key back-up position and non back-up position vis-a-vis present expanders. The latch also includes a fishing neck which is engaged by a pulling tool to retrieve the latch. The fishing neck and the equalizing valve of the latch are designed so that the fishing neck cannot be engaged by the pulling tool until the equalizing valve has opened the pressure equalizing passage. However, a long prong is not necessary to move the equalizing valve.
The detailed structure of a first embodiment of a latch, structured in accordance with this invention, is illustrated in FIG. 1.
The latch housing 10 is short enough to comprise one section of a pumpdown tool train. Its length enables it to pass through the conventional loop or curved portion of tubing prior to entry into the well. The housing 10 includes interconnected tubular sections 10a and 10b.
The well equipment to be run in the well flow conductor and locked in place by the latch may be attached to the housing 10. The illustrated well equipment 12 is a plug or cap which is attached to the tubular housing section 10b by threaded connection 14.
Carried on latch housing 10 is seal means 16 for sealing between the housing 10 and the inner wall 18 of the landing nipple 20 (see FIG. 2). When seal means 16 is in its seal effective position, two pressure regions are formed in the well flow conductor. One pressure region is located on the same side of seal means 16 as is the well equipment 12. The other pressure region is located on the side of seal means 16 which is opposite from the well equipment 12.
Pressure equalizing passage means 22 extends through the housing 10 between a region of pressure exterior of the housing and a region of pressure interior of the housing. The exterior pressure region would be the one pressure region located on the same side of seal means 16 as is the well equipment 12. The interior pressure region is in communication with the other pressure region on side of seal means 16 which is opposite the well equipment 12. The openings of the equalizing passage means 22 at the exterior and interior of the housing 10 are positioned to reduce, as much as possible, the overall longitudinal length of latch housing 10. The opening 22a at the exterior of the housing 10 is adjacent to seal means 16. The longitudinal length of latch housing 10 which accommodates equalizing passage means 22 is, therefore, no longer than the longitudinal length of seal means 16 plus the width of the equalizing passage means opening 22a. Equalizing passage means 22 has an opening 22b interior of the housing 10 positioned so that valve means 24, which is movable between positions permitting and preventing flow through interior opening 22b, does not extend beyond the extremities of latch housing 10 during its movement. As shown, the interior opening 22b of equalizing passage means 22 need not be aligned with the exterior opening 22a. Instead, passage means 22 includes a vertical portion extending between the two openings 22a and 22b.
Valve means 24 controls fluid flow through equalizing passage means 22. Valve means 24 permits flow through equalizing passage means 22 during running of the latch into the well flow conductor. It blocks flow through equalizing passage means 22 after the latch has been landed and locked in its landing nipple 20. Before the latch is unlocked from the landing nipple 20, valve means 24 is returned to its former position permitting flow through pressure equalizing passage means 22. For controlling flow through equalizing passage means 22, valve means 24 is movable between a first position (see FIG. 1) permitting flow through equalizing passage means 22 and a second position (see FIG. 4) preventing flow through the equalizing passage means 22. Valve means 24 includes port means 26, which are substantially aligned with the interior opening 22b of passage means 22 when valve means 24 is in its first position, to permit free flow of fluids through passage means 22. Spaced seal means 28 and 30 are carried by valve means 24. The spaced seal means 28 and 30 seal between valve means 24 and the interior surface of latch housing 10. They span the interior opening 22b of equalizing passage means 22 when valve means 24 is in its second position (see FIG. 4). When seal means 28 and 30 span the opening 22b, flow through equalizing passage means 22 is prevented.
Valve means 24 also engages the running tool prong while the latch is being run into the well flow conductor. The engagement of valve means 24 with the running tool prong joins the latch to the pumpdown tool train. Once the latch is landed and locked in the landing nipple 20, valve means 24 releases the running tool prong. Thereafter the running tool and pumpdown tool train may be retrieved from the well flow conductor leaving the latch and associated well equipment 12 landed and locked in the landing nipple 20.
A lower, inwardly facing shoulder 32 of valve means 24 is adapted to selectively engage the running tool prong and release the running tool prong. The inwardly facing shoulder 32 is formed on the lower end of resilient, inherently outwardly expandable collet fingers 34 associated with valve means 24. When valve means 24 is in its first position (see FIG. 1), the collet fingers 34 are collapsed and confined inwardly. The inward confinement of collet fingers 34 enables the engagement of the head of a running tool prong by inwardly facing shoulder 32. When valve means 24 is in its second position (see FIG. 4) the collet fingers 34 inherently assume an outwardly expanded position. The outwardly expanded position of the collet fingers 34 enables the head of a running tool prong to pass through inwardly facing shoulder 32. Latch housing 10 is provided with a reduced internal diameter by sleeve 36. Sleeve 36 collapses and confines collet fingers 36 inwardly when valve means 24 is in its first position. The length of sleeve 36 is such that collet fingers 34 are free to expand outwardly when valve means 24 is in its second position.
While the latch is being run into the well flow conductor, valve means 24 is releasably held in its first position, wherein collet fingers 34 are confined inwardly, so that the running tool prong head is not prematurely released and the latch separated from the pumpdown tool train. The illustrated releasable holding means comprises shear pin 38. Shear pin 38 is threaded into a socket 40 in the housing 10 and projects into a groove 42 of valve means 24. It, therefore, releasably holds valve means 24 in its first position with respect to the latch housing 10.
After the latch is landed and locked in the landing nipple 20, valve means 24 is moved to its second position preventing flow through equalizing passage means 22. Thereafter, valve means 24 is prevented from returning to its first position permitting flow through equalizing passage means 22 until it is desired to unlock the latch from the landing nipple. Releasable stop means, coacting between valve means 24 and the latch housing 10, prevent an unintentional movement of valve means 24 from its second position to its first position. The illustrated releaseable stop means comprises the lower outwardly facing shoulder 44 of collet fingers 34 and the upper end 46 of sleeve 36.
After shear pin 38 is sheared, valve means 24 is stopped when it reaches its second position by the engagement of an upwardly facing shoulder 48 of valve means 24 with a downwardly facing shoulder 50 within the latch housing 10. When valve means 24 is returned to its first position, its movement is stopped by the engagement of a downwardly facing shoulder 52 of valve means 24 with the upper end 46 of sleeve 36.
Radially movable key means 54 lock the latch in the recess 56 of the landing nipple 20. Key means 54 are carried by the latch housing 10 and are movable radially with respect to the latch housing 10 within windows 58 formed in tubular housing section 10a. The outer profile of key means 54 is designed to mate with the inner profile of landing nipple recess 56. The radial outward expansion of key means 54 into the recess 56 and the maintenance of key means 54 in an expanded position locks the latch in the landing nipple 20.
The latch is located with respect to the landing nipple 20, with key means 54 adjacent the landing nipple recess 56, by the engagement of downwardly facing shoulders 60 and 62 of key means 54 with upwardly facing shoulders 64 and 66 of recess 56. During downward movement of the latch through a well flow conductor, a lower chamfered shoulder 68 of key means 54 engages restrictions in the flow conductor and cams key means 54 inwardly. During upward movement of the latch through a well flow conductor, upward facing chamfered surfaces 70, 72 and 74 of key means 54 engage restrictions in the flow conductor and cam key means 54 inwardly. Such camming action enables the latch to by-pass restrictions in the well flow conductor.
Inherently resilient urging means, such as spring means 76, biases key means 54 radially outwardly with respect to the latch housing 10. To enable retraction of key means 54 into the latch housing 10, without interference due to the physical size of spring means 76, spring means 76 is disposed in a slot 78 formed in key means 54.
Expander means 80 expands key means 54 to their outermost position and thereafter backs up key means 54 to maintain them in that position. Expander means 80 is axially movable with respect to the latch housing 10 between a first and second position. In its first position, expander means 80 does not engage key means 54. Key means 54 is capable of completely retracting into the windows 58 of the latch housing 10. In its second position, expander means 80 engages key means 54 and maintains key means 54 in their outermost position.
Expander means 80 is prevented from inadvertently shifting between its first and second positions. Once in one of its first or second positions, expander means 80 is releasably maintained in that position. The illustrated releasable maintaining means for expander means 80 comprises an expandable and contractible detent ring means 82 which engages one of two spaced groove means 84 and 86. The expandable and contractible detent means 82 may be carried by one of expander means 80 and the latch housing 10 with the groove means 84 and 86 being in the other. Because of space limitations, in the illustrated latch, the expandable and contractible detent ring means 82 is carried within a recess 88 of expander means 80. The spaced groove means 84 and 86 are located in an upper extension 10c of the tubular housing section 10b. Detent ring means 82 releasably engages groove means 84 when expander means 80 is in its first position and releasably engages groove means 86 when expander means 80 is in its second position (see FIG. 1). Seal means 90 is disposed around the upper extension 10c of housing section 10b above the spaced groove means 84 and 86. Seal means 90 engages the inner wall of fishing neck means 104 and prevents sand from seeping into the spaced groove means 84 and 86. Seepage of sand into the spaced groove means 84 and 86 would inhibit the operation of detent ring means 82.
Key means 54 and expander means 80 are stepped to minimize the distance between the first and second positions of expander means 80. Minimizing the distance through which expander means 80 moves enables a corresponding minimization of the longitudinal length of the latch. Key means 54 and expander means 80 are also designed to avoid the formation of sand trap areas. As seen in FIG. 1, key means 54 has an inwardly facing stepped surface including a first surface 92 forming one step, a second surface 94 forming a second step, and a tapered surface 96 extending therebetween. Expander means 80 has an outer stepped portion sized to engage the stepped surfaces 92 and 94 of the key means 54 when expander means 80 is in its second position and sized to permit complete retraction of key means 54 into the latch housing 10 when expander means 80 is in its first position. The outer stepped portion of expander means 80 includes a reduced outside diameter portion 98, an enlarged outside diameter portion 100, and a tapered portion 102 extending between the reduced and enlarged diameter portions 98 and 100, respectively. When expander means 80 is in its first position (see FIG. 2), its reduced diameter portion 98 is disposed behind the one step surface 92 of key means 54. When expander means 80 is in its second position, its enlarged diameter portion 100 engages the one step surface 92 of key means 54 and its reduced diameter portion 98 engages the second step surface 94 of key means 54. The distance through which expander means 80 moves between its first and second positions is less than the length of key means 54 by at least approximately the length of the coacting stepped surface of key means 54 and the stepped portion of expander means 80.
The latch is retrieved from the landing nipple 20 by the engagement of a pulling tool with fishing neck means 104 associated with expander means 80. To minimize the longitudinal length of the latch, a major portion of fishing neck means 104 is received within the latch housing 10.
An upward application of force to the pulling tool moves fishing neck means 104 upwardly and thereby moves expander means 80 to its first position. A continued upward application of force to the pulling tool will result in fishing neck means 104 transmitting that force to the latch housing 10. Key means 54 is cammed inwardly and out of locking engagement with the landing nipple recess 56. Thereafter, the latch may be retrieved from the well flow conductor.
For engagement with the appropriate pulling tool, fish neck means 104 includes an internal recess 106. When valve means 24 is in its second position, its upward extension 24b prevents a pulling tool from engaging the fishing neck recess 106. When valve means 24 is in its first position, the extension 24b no longer interferes with the engagement of recess 106 by a pulling tool (see FIG. 1).
When the latch is being retrieved from the well flow conductor, upward forces are transmitted by the pulling tool to fising neck means 104. Fishing neck means 104 in turn applies an upward force to latch housing 10. The latch includes appropriate load bearing shoulders, one shoulder 108 is associated with fishing neck means 104 and the other shoulder 110 is on latch housing 10. The shoulders 108 and 110 engage during this upward transmission of forces. Preferably, the one shoulder 108 associated with fishing neck means 104 is provided by load ring means 108. Load ring means 108 permits an easier fabrication and assembly of parts. Additionally, it may be formed from a special material to reduce the likelihood of damage during use.
The running tool for this first embodiment of a high pressure latch is shown in FIGS. 2, 3 and 4.
The running tool includes an outer mandrel 112 having interconnected section 112a and 112b. The running tool mandrel 112 is attached to the pumpdown tool train (not shown) by connector 114.
Within the mandrel 112 is disposed a plunger element 116. The plunger element 116 is axially movable with respect to the mandrel 112 between a first extended position (as illustrated in FIG. 2) and a second retracted position (as illustrated in FIG. 3). Shear pin 118 releasably maintains plunger element 116 in its first extended position. After shear pin 118 has been sheared, plunger element 116 is prevented from moving past its first extended position by the engagement of a shoulder 120 of plunger 116 and a shoulder 122 of mandrel 112.
At one end 116a of plunger element 116 is formed a socket 124. The socket 124 receives the ball 126 formed on one end of the running tool prong 128.
At the other end of the running tool prong 128 is formed head 130. The head 130 has a shoulder 132 for engaging the inwardly facing shoulder 32 of the latch valve means 24. The head 130 is sized so that when valve means 24 is in its first position with its inwardly facing shoulder 32 engaging and confining the prong head shoulder 132, the tip 134 of the prong head 130 engages a stop surface 136 which is stationary with respect to latch housing 10.
The pulling tool for the high pressure latch is illustrated in FIGS. 5 and 6.
The pulling tool includes a tool body 140 formed of interconnected sections 140a and 140b. In the tool body 140 is disposed an axially movable plunger 142 and a stationary collet latching means 144. An emergency shear pin 146 releasably joins the plunger 142 to a movable shear sub 148 and shear ring 150. Axially movable through the shear sub 148 is a connector 152. Connector 152 is associated with the pumpdown tool train (not shown). A spacer ring 154 is carried by the tool body 140 and prevents emergency shear pin 146 from shearing when plunger 142 is moved upwardly with respect to the tool body 140. In an emergency, if after the pulling tool has engaged the latch, it is decided to leave the latch locked in the landing nipple, the plunger 142 is jarred downwardly with respect to the tool body 140. Shear sub 148 engages an annular surface 156 of collet latching means 144 and produces a force which shears emergency shear pin 146. The plunger 142 is thereafter able to gravitate downwardly with respect to the tool body 140 until it attains its extreme extended position. At that extreme extended position, its shoulder 158 engages a shoulder 160 of collet latching means 144.
The lower end of plunger element 142 comprises an enlarged head 162 above which extends a reduced diameter portion 164.
The lower portion of latching collet means 144 comprises a plurality of collet fingers 166 each of which includes a collet head 168 at its lower end.
When the pulling tool is being run in the well flow conductor to retrieve the latch, the plunger 142 is biased to a first upward position with respect to the tool body 140 by spring means 170. In this first position of plunger 142, the plunger head 162 is disposed behind the collet heads 168 and mantains them in an outward position. Downward movement of plunger 142 with respect to the tool body 140, caused by a downward force being applied to connector 152, will be arrested by the engagement of shear sub 148 with annular shoulder 156. At this intermediate, extended position of the plunger 142, the plunger's reduced diameter portion 164 is disposed behind the collet heads 168. Collet fingers 166 allow collet heads 168 to move to a contacted position. If the emergency shear pin 146 has been sheared and plunger 142 has gravitated to its extreme extended position, the reduced diameter portion 164 of plunger 146 will be disposed behind collet heads 168. The collet heads 168 may assume their contracted position when plunger 142 is in one of its intermediate or extreme extended positions.
In operation, the latch of this invention lands, locks and seals well equipment in a well flow conductor. The latch is short so that it may pass through curved portions of the well flow conductor.
To run the latch into the well, the running tool would be connected to the end of the tool train with connector 114. The latch valve means 24 is moved to its second upward position so that collet fingers 34 expand outwardly. The running tool prong 128 is inserted therethrough until its head 130 extends beyond the lower inwardly facing shoulder 32 of the valve means 24. Valve means 24 and the running tool prong 128 are moved together until valve means 24 is in its first downward position. The prong head 130 is thereby confined between the lower inwardly facing shoulder 32 of valve means 24 and the surface 136, as illustrated in FIG. 2. Shear pin 38 is threaded into the socket 40. Engagement of shear pin 38 with the groove 42 of valve means 24 releasably maintains valve means 24 in the position shown in FIG. 2 with valve means 24 releasably engaging the running tool prong 128. The plunger element 116 of the running tool is moved to its first extended position and shear pinned, with pin 118, to the tool mandrel 112. The running tool mandrel 112 is now spaced from the latch housing 10 with the ball 126 and socket 124 of the prong 128 and plunger element 116 disposed therebetween. Expander means 80 is moved to its first position and releasably maintained therein by the engagement of detent ring means 82 with groove means 84. The latch and running tool are now ready to be run in the well flow conductor.
During the running of the running tool and latch through the well flow conductor, the latch is able to articulate with respect to the running tool due to the universal connection between the running tool prong 128 to the plunger element 116. Spring means 76 resiliently urges key means 54 outwardly. When key means 54 encounters a restriction within the well flow conductor, its chamfered shoulder 68 cams it inwardly. Due to the inwardly stepped surface of key means 54 and the outer stepped portion of expander means 80, key means 54 is capable of retracting fully within the windows 58 of the latch housing 10. With key means 54 retracted, restrictions in the well flow conductor can be bypassed. The running tool and latch move through the flow conductor until key means 54 is opposite the landing nipple recess 56. Key means 54 is expanded outwardly into the recess 56 by spring means 76. The shoulders 60 and 62 of key means 54 positively engage the shoulders 64 and 66 of the recess 56 to stop further movement of the latch and running tool The latch and running tool are in the configuration shown in FIG. 2. Equalizing passage means 22 is still opened. Key means 54 are not yet locked in their expanded position.
A continued application of force, in a first, downward, direction applied to the running tool, locks key means 54 in their expanded position. A downward application of force to the running tool will shear running tool shear pin 118. The running tool mandrel 112 moves downwardly with respect to plunger element 116. The lower end of the running tool mandrel 112 engages the upper end of fishing neck means 104. A downward application of force is continued. Since fishing neck means 104 is associated with expander means 80, initial movement of fishing neck means 104 and expander means 80 is resisted due to the engagement of detent ring means 82 with groove means 84. Detent ring means 82 is cammed outwardly into recess 88. With continued downward force applied to the running tool mandrel 112, fishing neck means 104 and expander means 80 are moved downwardly until expander means 80 is in its second position. Detent ring means 82 moves along with expander means 80 and engages groove means 86 when expander means 80 reaches its second position. The running tool and latch are now in the configuration illustrated in FIG. 3. Key means 54 are backed up by expander means 80 and are locked in their expanded position. However, equalizing passage means 22 remains open and the head 130 of the running tool prong 128 remains confined by inwardly facing shoulder 32.
An upward application of force to the running tool closes the equalizing passage means 22 and permits the retrieval of the running tool through the well flow conductor. The initial upward application of force to the running tool moves the tool mandrel 112 upwardly until its shoulder 122 engages plunger element shoulder 120. Thereafter upward forces are transmitted from the running tool mandrel 112 through plunger element 116, prong 128 and valve means 24. This transmission of upward forces applies a shearing load to latch shear pin 38. A sufficient upward force application shears latch shear pin 38. Thereafter, a continued upward application of force to the running tool moves valve means 24 to its second position. Valve means 24 is stopped when it reaches this second position by the engagement of its shoulder 48 with latch housing shoulder 50. When valve means 24 reaches its second position, collet fingers 34 spring outwardly. The prong head 130 can pass through the inwardly facing shoulder 32 of collet fingers 34. The prong 128 may be withdrawn from the latch (as seen in FIG. 4) and the latch retrieved from the well flow conductor.
The latch is now locked in the landing nipple 20 of the well flow conductor. Seal means 16 seals between the latch housing 10 and the landing nipple 20. Valve means 24 prevents flow through equalizing passage means 22. Two pressure regions are established, one above the latch and the other below the latch. The well equipment 12, which is associated with the latch, is now landed, locked and sealed the well flow conductor.
To retrieve the latch and associated well equipment 12 from the well, the pulling tool is connected to the end of a tool train (not shown) with connector 152. The tool train is run through the well flow conductor until the pulling tool reaches the location of the latch. As the pulling tool approaches the latch, (see (FIG. 5) the head 162 of plunger 142 remains disposed between the collet heads 168 of collet latching means 144. As long as the plunger head 162 is disposed behind the collet heads 168, the collet heads 168 cannot retract and cannot be received within fishing neck means 104.
The pulling tool encounters the latch and is operated to engage the latch fishing neck means 104. The first interaction between the pulling tool and latch occurs when the collet heads 168 of the pulling tool strike the top of the latch's fishing neck means 104. An application of force to the tool train in a first, downward, direction moves connector 152 and plunger 142 downwardly with respect to the pulling tool body 140. The plunger is stopped at its intermediate, extended position. The reduced diameter portion 164 of plunger 142 is thereby moved to a position behind the collet heads 168. The collet heads 168 can now move inwardly. A continued application of force to the tool train in a first direction, forces the collet heads 168 inwardly into fishing neck means 104. However, the extension 24b of valve means 24 prevents the collet heads 168 from engaging the recess 106 of fishing neck means 104. The collet heads 168 instead engage the upper end of valve means 24. Movement of valve means 24 from its second position is initially resisted by the engagement of the outward facing shoulders 44 of valve collet fingers 34 with the upper end 46 of sleeve means 36 in the latch housing 10. Force is continued to be applied to the tool train in the first direction until this releasable stop means for valve means 24 is overcome. The collet fingers 34 chamfer inwardly. Valve means 24 moves to its first position with its stop shoulder 52 engaging the upper end 46 of sleeve means 36. Flow through pressure equalizing passage means 12, which equalizes the pressre across seal means 16, is permitted. The pulling tool collet heads 168 have now engaged the internal recess 106 of fishing neck means 104.
An application of force to the tool train in a second, upward, direction initially moves the plunger 142 and connector 152 upwardly. Their upward movement is arrested by the engagement of shear sub 148 with spacer ring 154. The plunger 142 is thus returned to its first position. Its enlarged head 162 is disposed under the collet heads 168 maintaining them engaged with fishing neck recess 106.
A continued application of force in this second direction unlocks the latch from the landing nipple 20 and retrieves the latch from the well flow conductor. The collet heads 168 of the pulling tool will remain engaged with the fishing neck means 104. Movement of fishing neck means 104 is initially resisted due to the engagement of detent ring means 82 with lower groove means 86. Upon a sufficient upward application of force, detent ring means 82 is cammed outwardly into recess 88. Fishing neck means 104 and the associated expander means 80 are now movable with respect to the latch housing 10 to the expander's first position. When expander means 80 is moved to its first postion, due to the forces being applied through the pulling tool and fishing neck means 104, load ring means 108 engages the latch housing shoulder 110. At the same time, key means 54 are permitted to retract inwardly into the latch housing 10. A continued application of force, in a second, upward direction, applied to the tool train will chamfer key means 54 inwardly. Improved force transmission between fishing neck means 104 and the latch housing 10 is provided by the engagement of load ring means 108 with shoulder 110. The latch can now be retrieved from the well as seen in FIG. 6.
FIGS. 7, 8 and 9 illustrate an alternate embodiment of a latch and running tool in accordance with this invention.
Except for key means 54a, the elements of the latch of this second embodiment correspond to the elements of the latch of the first embodiment. These corresponding elements have been designated with the corresponding numerals except for the addition of a'.
The key means 54a of this second embodiment locks the latch in a landing nipple 180. Key means 54a does not locate the latch with respect to a landing nipple as do key means 54 of the first embodiment. The outer profile of key means 54a includes downward facing chamferred surfaces 182, 184 and 186. These chamferred surfaces cam key means 54a inwardly when a restriction is encountered as the latch means downwardly through the well flow conductor. Except for chamferred surfaces 182, 184 and 186 key means 54a is the same as the key means 54 of the first embodiment.
The running tool includes means for stopping and locating the tool train in the well flow conductor. The running tool stops the tool train when the latch is in the landing nipple 180 with key means 54a opposite the landing nipple recess 188.
The running tool of this second embodiment also includes elements which correspond to the elements of the running tool of the first embodiment previously described. These corresponding elements have also been designated with the corresponding numerals except for the addition of a'. In addition to the elements previously described, the running tool includes a stop means, such stop collar 190 carried on tool mandrel 112'. Stop collar 190 is attached to the tool plunger element 116' by pin means 192. Pin means 192 extends through a slot 194 formed within mandrel 112'. Stop means 190 is therefore stationary with respect to the movable plunger element 116' and moves therewith after shear pin 118' has been sheared.
The operation of this second embodiment is similar to the operation of the first embodiment.
The latch and running tool are joined as part of a tool train in the manner previously described.
The tool train is run through the well flow conductor until stop means 190 of the running tool engages a stop shoulder 196 in the landing nipple 180. When the tool train is stopped latch key means 54a are opposite the landing nipple recess 188. They are resiliently expanded outwardly into the recess 188 by spring means 76'. (See FIG. 7.)
Once the running tool is stopped, and key means 54a have expanded into the recess 188, a continued application of force in a first, downward direction, shears running tool shear pin 118'. Thereafter the running tool operates to lock the latch in the landing nipple 180 in the manner previously described. The latch valve means 24' is also moved to its position preventing flow through equalizing passage means 22' and releasing the running rool prong 128' in the manner previously described.
The latch may be retrieved with a pulling tool in the manner previously described.
From the foregoing it can be seen that the objects of this invention have been obtained. A high pressure latch for pumpdown use has been provided. Any desired well tool may be connected to the latch. The latch comprises one short section of a pumpdown tool train. It is therefore able to negotiate a short radius of curvature which may be present in the well flow conductor. The longitudinal length of the latch is kept to a minimum by reducing the distance that a key expander moves between its (the expander's) effective and ineffective positions. The longitudinal length of the latch is also shortened by the arrangement of the pressure equalizing passage and valve. Additionally, a major portion of the fishing neck is received within the latch housing. Once the latch has been locked in position in the well, the equalizing passage is closed by the valve and the latch cannot be retrieved from the well without moving the valve to a position permitting pressure equalization through the equalizing passage.
The foregoing disclosure and description of the invention are illustrative and explanatory thereof. Various changes in the size, shape, and materials, as well as the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.
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Disclosed is a well latch for locking well tools in a well flow conductor. The latch housing has a pressure equalizing passage extending through its wall. A valve controls flow through the equalizing passage. Keys, carried by the latch housing, are expanded outwardly into a locking groove of a well flow conductor to lock the well latch therein. A fishing neck, associated with the latch, permits retrieval of the latch. This abstract is neither intended to define the scope of the invention, which, of course, is measured by the claims, nor is it intended to be limiting in any way.
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BACKGROUND
Fracturing and other pressure based operations that occur at intervals along the length of a borehole often rely upon plugs (balls, darts, etc.) that are dropped or pumped to seats installed within the borehole. Upon landing at individual ones of such seats, pressure may be applied to actuate a tool or fracture a formation location. Because of a limited number of plug diameters that are practically possible, such systems are limited in the number of pressure events that can be created.
While the art has been using such systems for years and coping well with the limitations thereof, an alternative that would increase the number of events that could be created would be welcomed by the art.
SUMMARY
A system including a plurality of differential pressure actuated tools; a seat receptive to a plug; a first conduit fluidly communicating tubing pressure upstream of the seat to one end of each of the plurality of tools; and a second conduit fluidly communicating tubing pressure downstream of the seat to an opposite end of each of the plurality of tools.
A method for actuating a plurality of tools in a downhole environment including deploying a plug into a borehole including a plurality of differential pressure actuated tools; a seat receptive to a plug; a first conduit fluidly communicating tubing pressure upstream of the seat to one end of each of the plurality of tools; and a second conduit fluidly communicating tubing pressure downstream of the seat to an opposite end of each of the plurality of tools; landing the plug in the seat; creating a differential pressure across each of the plurality of tools; and actuating the plurality of tools with the differential pressure.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings wherein like elements are numbered alike in the Figures:
FIG. 1 is a schematic illustration of a frac sleeve system in a pre actuation condition;
FIG. 2 is a schematic view of the same system in the actuated position.
DETAILED DESCRIPTION
Referring to FIG. 1 , a system 10 having more than one actuable tool 12 is illustrated. In the illustrations herein only two tools 12 are illustrated but it is to be appreciated that any plurality of tools 12 may be employed in the system. The overall concept of the system and method is the facilitation of an ability to actuate a plurality of tools based upon pressure applied from a remote location pursuant to a single plug being landed. The prior art, as noted above only actuates one tool per plug while the invention actuates any plurality.
As illustrated simply for ease of discussion, the tools 12 are sliding sleeves that include piston chambers 14 that are ported to the ID 16 of a string 18 at both an uphole end 20 and a downhole end 22 by conduits 24 and 26 , respectively. The conduits 24 and 26 may actually comprise control line run from the ends of the piston chambers 14 or may be simply fluid pathways through the tools. It is unimportant to the operation of the system how the fluid within the piston chamber is communicated to the ID upstream and downstream of the seat 28 but rather only that it is so communicated for that is the configuration that allows a differential pressure to be provided to a plurality of tools simultaneously. It is to be appreciated that both, or all in the case of more tools 12 , of the conduits 26 fluidly connect with the ID 16 downstream of a seat 28 while both, or all in the case of more tools 12 , of the conduits 24 fluidly connect to the ID 16 upstream of the seat 28 . The seat, with an accompanying plug 32 (see FIG. 2 ), then provides for the differential pressure noted above that is generatable across both (or all) of tools 12 at the same time. The tools 12 are actuated simultaneously by pressuring up on the string 18 after the seating of the single plug 32 (see FIG. 2 ).
It is also to be noted that it is not important where the conduits 24 and 26 end up connecting to the ID other than that conduits 24 must connect at one of upstream and downstream of the seat 28 and conduits 26 must connect at the other of upstream or downstream of the seat 28 , or in other words across the seat 28 , so that differential pressure can be generated. Where precisely they connect after that consideration is met is a matter of manufacturing convenience and material cost. Further, although in the example both of the tools 12 are “actuated” at the same time that does not necessarily mean that they must both move at the same rate to open. In some particular applications, one or more could be delayed if desired but the actuation pressure, which is a differential pressure across the seat 28 , and hence across pistons 34 in each chamber 14 , occurs simultaneously.
It is to be appreciated that the system illustrated in FIGS. 1 and 2 can be stacked. This may be effected schematically simply by copying FIG. 1 and pasting the duplicate longitudinally adjacent the first illustration. Each system then would have a plurality of tools 12 , a seat 28 , a set of conduits 24 fluidly connected to the string 18 on one side of the seat 28 and a set of conduits 26 fluidly connected to the string 18 on the other side of the seat 28 .
In a borehole configured with the system as disclosed, one or more of the systems 10 may be employed and in some embodiments a large number of the systems are employed. The number of tools 12 actuated by each plug 32 is not limited and the number of systems 10 is limited only by the number of configurations, such as plugs, that can produce a location across which differential pressure may be generated.
With respect to other pluralities of tools that are uphole of the plurality of tools shown in FIGS. 1 and 2 , these will not be actuated by the pressure in the string 18 that is intended to actuate the plurality of tools 12 that are shown. This is because if there is no plug 32 in a seat that is associated with a particular plurality of tools 12 , there can be no pressure differential developed across the pistons 34 . Rather, pressurization of the string 18 without a plug 32 in a seat 28 that is associated with a particular plurality of tools 12 is applied to both sides of the piston chambers 14 , whereby the piston 34 in each will not move. A Seat 28 considered “associated” with a particular plurality of tools 12 is the seat 28 that is located between conduits 24 and 26 for a particular plurality of tools 12 .
Following tool actuation, pressure may also be used to, for example, fracture the formation through the tools, which may be, for example, valves such as open sliding sleeves, for example. Since other tools are experiencing balanced pressure, they and the formation at those tools is unaffected. Uphole of the particular system, the tools are unactuated and thence pressure is irrelevant and downhole of the particular system, pressure is hydrostatic alone due to the seated plug 32 at the particular system. It will be appreciated that seals 40 are positioned outside of string 18 to isolate individual zones.
Finally it is to be understood while one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.
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A system including a plurality of differential pressure actuated tools; a seat receptive to a plug; a first conduit fluidly communicating tubing pressure upstream of the seat to one end of each of the plurality of tools; and a second conduit fluidly communicating tubing pressure downstream of the seat to an opposite end of each of the plurality of tools and method.
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BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention generally relates to shock absorbing line attachments, and in its preferred embodiments more specifically relates to a shock absorbing attachment for animal tethers and leashes.
[0003] 2. Background Art
[0004] The walking of an animal on a leash is a common practice, as is the tethering of an animal to an immovable object for the purpose of allowing it to move around while not being able to leave a designated area. Sudden movements by the animal may cause a substantial shock to the animal, and in the case of walking with a leash, to the animal's handler as well. A conventional tether or leash provides no shock-absorption for either animal or handler to cushion or absorb these shocks.
[0005] Elastic leashes and leashes with elastic portions have been created in an effort to remedy this problem, but they must be used instead of any leash already owned by the handler, and force the handler to sacrifice control. Without grasping the animal's harness or collar directly, the elasticity is ever-present, not allowing the handler to correct the animal using the conventional method of a sharp tug on the leash. Additionally, these leashes are designed only for walking and do not address the problem that still exists when tethering the animal to an immovable object.
[0006] Elastic leash couplers have been created to allow for use with a leash already owned by the handler, but they suffer from the same control problem as elastic leashes, because they are attached between the leash and the collar. Additionally, these couplers have another drawback in that no matter how strong the original leash or tether is, once the elastic coupler is attached the entire leash or tethering system will be only as strong as the elastic coupler.
[0007] There remains a need for an elastic attachment that can easily be used with an already owned leash or tether, that will not weaken the link formed by the leash or tether, and that will not reduce a handler's ability to control and correct an animal.
BRIEF SUMMARY OF THE INVENTION
[0008] In accordance with the invention there is provided an elongate elastic member having openings at each of its two ends, wherein a tether or leash can pass through one of said openings, winding spirally around the elastic member before passing through the opening at the opposite end.
[0009] The present invention can be easily applied to a commercially available leash or one already owned by an animal handler, with no special skill required, and while retaining the look and style of the original leash. The present invention can also be easily attached to a tether, sometimes called a tie-out. The present invention can be removed from a leash or tether at any time, without damaging either the present invention or the leash or tether.
[0010] When the present invention is properly attached to a leash or tether, a section of the leash or tether becomes substantially elastically stretchable, and is able to absorb shocks created by sudden movements at either end of the leash or tether.
[0011] Unlike elastic leash couplers in the prior art, whether using the present invention with a leash or a tether, no weakening of the link created by the leash or tether will occur. If the present invention fails in any way, and for any reason, the leash or tether will continue to function just as it would if the present invention were not used.
[0012] Unlike elastic leashes, leashes with elastic portions, and elastic leash couplers in the prior art, the present invention can be used to make any portion of a leash substantially elastic. Thus, the present invention can be attached to a leash closer to the end held by a handler than the end linked to an animal's collar. In doing so, the handler is still able to hold the leash in between the portion made elastic by the present invention and the animal's collar. Thus, the handler can still have the same amount of control that would be provided by the same leash when the current invention is not attached, and can still correct an animal with sharp tugs, or allow the present invention to absorb some of the shock of correcting tugs, at the handler's own discretion.
[0013] The structure and features of the preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawing figures.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0014] FIG. 1 is a top elevation of a preferred embodiment in an un-stretched state.
[0015] FIG. 2 is a top elevation of a preferred embodiment in an un-stretched state and attached to a leash.
[0016] FIG. 3 is a side elevation of a preferred embodiment in an un-stretched state and attached to a leash.
[0017] FIG. 4 is a top elevation of a preferred embodiment in a stretched state.
[0018] FIG. 5 is a top elevation of a preferred embodiment in a stretched state and attached to a leash.
[0019] FIG. 6 is a perspective view of a preferred embodiment attached to a leash closer to the end held by a handler than the end linked to an animal's collar.
DETAILED DESCRIPTION OF THE INVENTION
[0020] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments of the invention only and is not intended to be limiting.
[0021] Referring now to FIG. 1 , there is shown an elongate elastic member 10 , having a first flange 12 projecting parallel with the axis of elastic member 10 at one end and a second flange 14 projecting parallel with the axis of elastic member 10 at the other end. Each flange is perforated to form a first eyelet 16 and a second eyelet 18 . Elastic member 10 is shown in an un-stretched state.
[0022] Preferred materials for elastic member 10 are rubber or elastomer, bungee or shock cord, elastic fabric, metal coil spring enclosed in a stretchable tubular housing, woven rubber strands, or any sufficiently elastic, strong and light material or combination of materials. The most preferred material for elastic member 10 is rubber or elastomer.
[0023] Preferred materials for the flanges 12 and 14 are a continuation of the material of elastic member 10 , or any sufficiently strong and light material or combination of materials that can be permanently bonded to the elastic member. The most preferred material for the flanges 12 and 14 is a continuation of the material of elastic member 10 .
[0024] Some presently preferred sizes or dimensions are given herein for the purpose of illustration, and not for the purpose of limitation. A preferred length for elastic member 10 may be approximately 6-14 inches. A preferred width or diameter for elastic member 10 may be 0.25-0.75 inches.
[0025] Referring now to FIGS. 2 and 3 , there is shown a leash 20 passing through eyelet 16 , spirally wound around elastic member 10 , and then passing through eyelet 18 . Eyelets 16 and 18 should be large enough in diameter to allow at least one end of leash 20 to pass through. If flanges 12 and 14 are made of a stretchable material, eyelets 16 and 18 may be too small in diameter to allow either end of leash 20 to pass through, provided at least one end of leash 20 can pass through said eyelets when said flanges are stretched. By spirally winding leash 20 around elastic member 10 , elastic member 10 is caused to substantially retain its position on leash 20 by friction. Because elastic member 10 is held in place on leash 20 by friction, eyelets 16 and 18 do not need to attach to or grip leash 20 , as long as leash 20 can pass through said eyelets.
[0026] Leash 20 is spirally wound around elastic member 10 six times for the purpose of illustration, and not for the purpose of limitation. The number of times a leash or tether may be spirally wound around elastic member 10 during actual use of the present invention depends upon several factors including the exact dimensions of elastic member 10 , the width or diameter of the leash or tether, and the difference between the un-stretched length of elastic member 10 and the maximum length to which elastic member 10 can be elastically stretched.
[0027] Leash 20 is shown for the purpose of illustration, and not for the purpose of limitation. Any suitable leash or tether could be used with the present invention in place of leash 20 .
[0028] Referring now to FIG. 4 , there is shown the same preferred embodiment as shown in FIG. 1 , but in an elastically stretched state. Elastic member 10 should preferably be elastically stretchable to between 150% and 200% of its un-stretched length.
[0029] Referring now to FIG. 5 , there is shown the same preferred embodiment attached to leash 20 as shown in FIGS. 2 and 3 , but in an elastically stretched state. Illustrated in FIG. 5 is the effect on leash 20 caused by stretching elastic member 10 . The coil formed by the spiral winding of leash 20 illustrated in FIGS. 2 and 3 is elongated by straining elastic member 10 in torsion and tension. The overall length of leash 20 is at first shortened by spirally winding it around elastic member 10 , but when elastic member 10 is stretched as shown in FIG. 5 , the overall length of leash 20 approaches the original length of leash 20 when the present invention is not attached.
[0030] Referring now to FIG. 6 , there is shown an illustration of a typical leash, held at one end by a handler and linked at the other end to a dog's collar. The present invention is attached to the leash, closer to the end held by the handler than the end linked to the collar. The present invention is shown in an un-stretched state, making the overall length of the leash shorter than the leash's original length. The dog, handler, and leash shown in FIG. 6 are shown for the purpose of illustration, and not for the purpose of limitation.
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A shock absorbing leash attachment comprising an elastic member around which a common animal tether or leash is spirally wound, the two ends of the tether or leash passing through openings at each end of the elastic member respectively. Shock on the tether or leash is absorbed by straining the elastic member in torsion and tension.
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BACKGROUND OF THE INVENTION
[0001] In the manufacture of paper products, it is often desirable to enhance physical and/or optical properties by the addition of chemical additives. Typically, chemical additives such as softeners, colorants, brighteners, strength agents, etc. are added to the fiber slurry upstream of the headbox in a paper making machine during the manufacturing or converting stages of production to impart certain attributes to the finished product. These chemical additives are usually mixed in a stock chest or stock line where the fiber slurry has a fiber consistency of from between about 0.15 to about 5 percent or spraying the wet or dry paper or tissue during production.
[0002] One disadvantage of adding a chemical additive at each paper machine is that the manufacturer has to install equipment on each paper machine to accomplish the chemical additive addition. This, in many cases, is a costly proposition. In addition, the uniformity of the finished product coming off of each paper machine may vary depending upon how the chemical additive was added, variations in chemical additive uniformity and concentrations, the exact point of chemical additive introduction, water chemistry differences among the paper machines as well as personnel and operational differences of each paper machine.
[0003] Another difficulty associated with wet end chemical additive addition is that the water soluble or water dispersible chemical additives are suspended in water and are not completely adsorbed or retained onto the fibers prior to formation of the wet mat. To improve adsorption of wet end chemical additives, the chemical additives are often modified with functional groups to impart an electrical charge when in water. The electrokinetic attraction between charged chemical additives and the anionically charged fiber surfaces aids in the deposition and retention of chemical additives onto the fibers. Nevertheless, the amount of the chemical additive that can be adsorbed or retained in the paper machine wet end generally follows an adsorption curve exhibiting diminishing incremental adsorption with increasing concentration, similar to that described by Langmuir. As a result, the adsorption of water soluble or water dispersible chemical additives may be significantly less than 100 percent, particularly when trying to achieve high chemical additive loading levels.
[0004] Consequently, at any chemical addition level, and particularly at high addition levels, a fraction of the chemical additive is retained on the fiber surface. The remaining fraction of the chemical additive remains dissolved or dispersed in the suspending water phase. These unadsorbed or unretained chemical additives can cause a number of problems in the papermaking process. The exact nature of the chemical additive will determine the specific problems that may arise, but a partial list of problems that may result from unadsorbed or unretained chemical additives includes: foam, deposits, contamination of other fiber streams, poor fiber retention on the machine, compromised chemical layer purity in multi-layer products, dissolved solids build-up in the water system, interactions with other process chemicals, felt or fabric plugging, excessive adhesion or release on dryer surfaces, physical property variability in the finished product.
[0005] Therefore, what is lacking and needed in the art is a method for applying chemical additives onto pulp fiber surfaces in the initial or primary pulp processing, providing more consistent chemical additive additions to the pulp fiber and a reduction or elimination of unretained chemical additives in the process water on a paper machine. The method minimizes the associated manufacturing and finished product quality problems that would otherwise occur with conventional wet end chemical addition at the paper machine.
SUMMARY OF THE INVENTION
[0006] It has now been discovered that chemical additives can be applied to pulp fibers at high and/or consistent levels with at most a minimal amount of unretained chemical additives present in the papermaking process water after the treated pulp fiber has been redispersed in water. This is accomplished by treating a fibrous web prior to the finishing operation at a pulp mill with a chemical additive, completing the finishing operation, redispersing the finished pulp at the paper mill and using the finished pulp in the production of a paper product.
[0007] Hence in one aspect, the invention resides in a method for applying chemical additives to the pulp fibers. The method comprises creating a fiber slurry comprising water and pulp fibers. The fiber slurry is formed into a wet fibrous web using a web forming apparatus. The wet fibrous web is dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. A chemical additive is applied to the dewatered fibrous web, thereby forming a chemically treated dewatered fibrous web. In other embodiments of the present invention, the process may include further dewatering of the dewatered fibrous web, thereby forming a crumb-form before or after the application of the chemical additive. The chemically treated dewatered fibrous web contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The chemically treated pulp fiber is then used in a separate process to produce paper product.
[0008] In another aspect, the invention resides in a method for applying chemical additives to the pulp fibers. The method comprises creating a fiber slurry comprising water and pulp fibers. The fiber slurry is formed into a wet fibrous web using a web forming apparatus. The wet fibrous web is dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. In other embodiments of the present invention, the process may include further dewatering of the dewatered fibrous web, thereby forming a crumb-form. The dewatered fibrous web is dried to a predetermined consistency, thereby forming a dried fibrous web. A chemical additive is applied to the dried fibrous web, thereby forming a chemically treated dried fibrous web. The chemically treated dried fibrous web contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The chemically treated pulp fiber is then used in a separate process to produce paper product.
[0009] According to another embodiment of the present invention is a method for applying a chemical additive to the pulp fiber during the pulp processing stage. During the pulp processing stage, upstream of a paper machine, one can obtain chemically treated pulp fiber. Furthermore, the chemically treated pulp fiber can be transported to several different paper machines that may be located at various sites, and the quality of the finished product from each paper machine will be more consistent. Also, by chemically treating the pulp fiber before the pulp fiber is made available for use on multiple paper machines or multiple runs on a paper machine, the need to install equipment at each paper machine for the chemical additive addition can be eliminated.
[0010] The term “unretained” refers to any portion of the chemical additive that is not retained by the pulp fiber and thus remains suspended in the process water. The term “web-forming apparatus” includes fourdrinier former, twin wire former, cylinder machine, press former, crescent former, and the like used in the pulp stage known to those skilled in the art. The term “water” refers to water or a solution containing water and other treatment additives desired in the papermaking process. The term “chemical additive” refers to a single treatment compound or to a mixture of treatment compounds. It is also understood that a chemical additive used in the present invention may be an adsorbable chemical additive.
[0011] The consistency of the dried fibrous web is from about 65 to about 100 percent. In other embodiments, the consistency of the dried fibrous web is from about 80 to about 100 percent or from about 85 to about 95 percent. The consistency of the dewatered fibrous web is from about 20 to about 65 percent. In other embodiments, the consistency of the dewatered fibrous web is from about 40 to about 65 percent or from about 50 to about 65 percent. The consistency of the crumb form is from about 30 to about 85 percent. In other embodiments, the consistency of the crumb form is from about 30 to about 60 percent or from about 30 to about 45 percent.
[0012] The present method allows for the production of pulp fibers that are useful for making paper products. One aspect of the present invention is a uniform supply of chemically treated pulp fiber, replacing the need for costly and variable chemical treatments at one or more paper machines.
[0013] In another embodiment, the chemically treated pulp fiber slurry of the present invention comprises process water and having an applied chemical additive retained by the pulp fibers. The amount of chemical additive retained by the chemically treated pulp fibers is about 0.1 kilogram per metric ton or greater. In particularly desirable embodiments, the amount of retained chemical additive is about 0.5 kg/metric ton or greater, particularly about 1 kg/metric ton or greater, and more particularly about 2 kg/metric ton or greater. Once the chemically treated pulp fibers are redispersed at the paper machine, the amount of unretained chemical additive in the process water phase is between 0 and about 50 percent, particularly between 0 and about 30 percent, and more particularly between 0 and about 10 percent, of the amount of chemical additive retained by the pulp fibers.
[0014] According to one embodiment of the present invention, the method for adding a chemical additive to pulp fiber comprises creating a fiber slurry. The fiber slurry comprises water and pulp fibers. The fiber slurry is passed to a web-forming apparatus of a pulp sheet machine where a wet fibrous web is formed from the fiber slurry. The wet fibrous web is dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. The dewatered fibrous web is dried to a predetermined consistency, thereby forming a dried fibrous web. A chemical additive is then applied to the dried fibrous web. The resulting chemically treated dried fibrous web contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The chemically treated dried fibrous web may be transported to a paper machine. The chemically treated dried fibrous web is mixed with process water to form a chemically treated pulp fiber slurry. The chemically treated pulp fiber slurry contains the fibers having the chemical additive secured thereto or retained thereby. A finished product having enhanced quality due to the retention of the chemical additive by the chemically treated pulp fibers may be produced from the chemically treated pulp fiber slurry.
[0015] Another aspect of the present invention resides in a method for making chemically treated paper products. The method comprising mixing pulp fibers with water to form a fiber slurry. The fiber slurry is formed into a wet fibrous web. This may be accomplished in a web-forming apparatus of a pulp sheet machine. The wet fibrous web may be dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. A chemical additive is then applied to the dewatered fibrous web. The resulting chemically treated dewatered fibrous web contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The chemically treated pulp fibers, as a chemically treated dewatered fibrous web, may be transported or otherwise delivered to one or more paper machines. The chemically treated pulp fiber, as a chemically treated dewatered fibrous web, is mixed with process water to form a chemically treated pulp fiber slurry. The chemically treated pulp fiber slurry contains the chemically treated pulp fibers having the chemical additive secured thereto or retained thereby. A finished product having enhanced qualities due to the retention of the chemical additive by the chemically treated pulp fibers may be produced.
[0016] Another aspect of the present invention resides in a method for making chemically treated paper products. The method comprising mixing pulp fibers with water to form a fiber slurry. The fiber slurry is formed into a wet fibrous web. This may be accomplished in a web-forming apparatus of a pulp sheet machine. The wet fibrous web may be dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. A chemical additive is then applied to the dewatered fibrous web, thereby forming a chemically treated dewatered fibrous web. The resulting chemically treated dewatered fibrous web contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The chemically treated dewatered fibrous web is dried to a predetermined consistency, thereby forming a chemically treated dried fibrous web. The resulting chemically treated dried fibrous web contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The chemically treated pulp fibers, as a chemically treated dried fibrous web, may be transported or otherwise delivered to one or more paper machines. The chemically treated pulp fiber, as a chemically treated dried fibrous web, is mixed with process water to form a chemically treated pulp fiber slurry. The chemically treated pulp fiber slurry contains the chemically treated pulp fibers having the chemical additive secured thereto or retained thereby. A finished product having enhanced qualities due to the retention of the chemical additive by the chemically treated pulp fibers may be produced.
[0017] Another aspect of the present invention resides in a method for making chemically treated paper products. The method comprising mixing pulp fibers with water to form a fiber slurry. The fiber slurry is formed into a wet fibrous web. This may be accomplished in a web-forming apparatus of a pulp sheet machine. The wet fibrous web may be dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. The dewatered fibrous web is dried to a predetermined consistency, thereby forming a dried fibrous web. A chemical additive is then applied to the dried fibrous web. The resulting chemically treated dried fibrous web contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The chemically treated pulp fibers, as a chemically treated dried fibrous web, may be transported or otherwise delivered to one or more paper machines. The chemically treated pulp fiber, as a chemically treated dried fibrous web, is mixed with process water to form a chemically treated pulp fiber slurry. The chemically treated pulp fiber slurry containing the chemically treated pulp fibers having the chemical additive secured thereto or retained thereby. A finished product having enhanced qualities due to the retention of the chemical additive by the chemically treated pulp fibers may be produced.
[0018] Another aspect of the present invention resides in a method for making chemically treated finished paper or tissue products. The method comprising mixing pulp fibers with water to form a fiber slurry. The fiber slurry is formed into a wet fibrous web. This may be accomplished in a web-forming apparatus of a pulp sheet machine. The wet fibrous web may be dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. A chemical additive is applied to the dewatered fibrous web, thereby forming a chemically treated dewatered fibrous web. In other embodiments, the dewatered fibrous web may be processed to a wet lap or processed to a crumb form before or after the application of the chemical additive. The resulting chemically treated pulp fiber contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The chemically treated dewatered fibrous web, once treated with the chemical additive, may be transported or otherwise delivered to one or more paper machines in the chemically treated form of a dewatered fibrous web, a dried fibrous web, a wet lap, or a crumb form. The chemically treated pulp fiber, as a wet fibrous web, a wet lap, or a crumb form, is mixed with process water to form a chemically treated pulp fiber slurry. The chemically treated pulp fiber slurry contains the chemically treated pulp fibers having the chemical additive secured thereto. A finished product having enhanced qualities due to the retention of the chemical additive by the chemically treated pulp fibers is produced.
[0019] Another aspect of the present invention resides in a method for making chemically treated finished paper or tissue products. The method comprising mixing pulp fibers with water to form a fiber slurry. The fiber slurry is formed into a wet fibrous web. This may be accomplished in a web-forming apparatus of a pulp sheet machine. The wet fibrous web may be dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. A chemical additive is applied to the dewatered fibrous web, thereby forming a chemically treated dewatered fibrous web. In other embodiments, the dewatered fibrous web may be processed to a wet lap or processed to a crumb form before or after the application of the chemical additive. The resulting chemically treated pulp fiber contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The chemically treated dewatered fibrous web is dried to a predetermined consistency, thereby forming a chemically treated dried fibrous web. The resulting chemically treated dried fibrous web contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The dried fibrous web, once treated with the chemical additive, may be transported or otherwise delivered to one or more paper machines in the chemically treated form of a dried fibrous web. The chemically treated pulp fiber, as a chemically treated dried fibrous web, is mixed with process water to form a chemically treated pulp fiber slurry. The chemically treated pulp fiber slurry contains the chemically treated pulp fibers having the chemical additive secured thereto. A finished product having enhanced qualities due to the retention of the chemical additive by the chemically treated pulp fibers is produced.
[0020] Another aspect of the present invention resides in a method for making chemically treated finished paper or tissue products. The method comprising mixing pulp fibers with water to form a fiber slurry. The fiber slurry is formed into a wet fibrous web. This may be accomplished in a web-forming apparatus of a pulp sheet machine. The wet fibrous web is dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. The dewatered fibrous web is dried to a predetermined consistency, thereby forming a dried fibrous web. A chemical additive is applied to the dried fibrous web, thereby forming a chemically treated dried fibrous web. In other embodiments, the dewatered fibrous web may be processed to a wet lap or processed to a crumb form before or after the application of the chemical additive. The resulting chemically treated pulp fiber contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water. The chemically treated dried fibrous web, once treated with the chemical additive, may be transported or otherwise delivered to one or more paper machines in the chemically treated form of a dried fibrous web, a dried fibrous web, a wet lap, or a crumb form. The chemically treated pulp fiber, as a wet fibrous web, a wet lap, or a crumb form, is mixed with process water to form a chemically treated pulp fiber slurry. The chemically treated pulp fiber slurry contains the chemically treated pulp fibers having the chemical additive secured thereto. A finished product having enhanced qualities due to the retention of the chemical additive by the chemically treated pulp fibers is produced.
[0021] Another aspect of the present invention resides in a method for making chemically treated paper products. The method comprises creating a fiber slurry comprising water and pulp fibers. The fiber slurry is formed into a wet fibrous web. This may be accomplished in a web-forming apparatus of a pulp sheet machine. The wet fibrous web may be dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. In other embodiments, the pulp fiber may be processed to a wet lap or processed to a crumb form. A first chemical additive is applied to the dewatered fibrous web. At least a second chemical additive may be applied to the dewatered fibrous web, thereby forming a multi-chemically treated dewatered fibrous web. The second chemical additive may be added simultaneously with the first chemical additive or at different times or points of the pulp processing stage. The multi-chemically treated dewatered fibrous web, containing the first and second chemical additives, may be further dried to a predetermined consistency, thereby forming a chemically treated dried fibrous web. The resulting chemically treated dried fibrous web may have from about 10 to about 100 percent retention of the applied first and second chemical additives. The resulting chemically treated pulp fibers contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of at least each of the first and second chemical additives when the chemically treated pulp fibers are redispersed in water. The chemically treated pulp fibers, as a multi-chemically treated dried fibrous web or as a multi-chemically treated dewatered fibrous web, are transported or otherwise delivered to one or more paper machines. The chemically treated pulp fiber, as a chemically treated dried fibrous web or a chemically treated dewatered fibrous web, are mixed with process water to form a chemically treated pulp fiber slurry. The chemically treated pulp fiber slurry contains the chemically treated pulp fibers having the chemical additives secured thereto. A finished product having enhanced qualities due to the retention of the chemical additives by the chemically treated pulp fibers may be produced.
[0022] Another aspect of the present invention resides in a method for making chemically treated paper products. The method comprises creating a fiber slurry comprising water and pulp fibers. The fiber slurry is formed into a wet fibrous web. This may be accomplished in a web-forming apparatus of a pulp sheet machine. The wet fibrous web may be dewatered to a predetermined consistency, thereby forming a dewatered fibrous web. The dewatered fibrous web may be dried to a predetermined consistency, thereby forming a dried fibrous web. In other embodiments, the pulp fiber may be processed to a wet lap or processed to a crumb form. A first chemical additive is applied to the dried fibrous web. At least a second chemical additive may be applied to the dried fibrous web, thereby forming a multi-chemically treated dried fibrous web. The second chemical additives may be added simultaneously with the first chemical additives or at different times or points of the pulp processing. The resulting chemically treated dried fibrous web contains chemically treated pulp fibers that have retained from between about 10 to about 100 percent of the applied amount of at least each of the first and second chemical additives when the chemically treated pulp fibers are redispersed in water. The chemically treated pulp fibers, as a multi-chemically treated dried fibrous web, are transported or otherwise delivered to one or more paper machines. The chemically treated pulp fibers, as a chemically treated dried fibrous web, are mixed with process water to form a chemically treated pulp fiber slurry. The chemically treated pulp fiber slurry contains the chemically treated pulp fibers having the chemical additives secured thereto. A finished product having enhanced qualities due to the retention of the chemical additives by the chemically treated pulp fibers may be produced.
[0023] The present invention is particularly useful for adding chemical additives such as softening agents to the pulp fibers, allowing for the less problematic and lower cost production of finished products having enhanced qualities provided by the retained chemical additives by the pulp fibers.
[0024] Hence, another aspect of the present invention resides in paper products formed from pulp fibers that have been chemically treated to minimize the amount of residual, unretained chemical additives in the process water on a paper machine. The term “paper” is used herein to broadly include writing, printing, wrapping, sanitary, and industrial papers, newsprint, linerboard, tissue, bath tissue, facial tissue, napkins, wipers, wet wipes, towels, absorbent pads, intake webs in absorbent articles such as diapers, bed pads, meat and poultry pads, feminine care pads, and the like made in accordance with any conventional process for the production of such products. With regard to the use of the term “paper” as used herein includes any fibrous web containing cellulosic fibers alone or in combination with other fibers, natural or synthetic. It can be layered or unlayered, creped or uncreped, and can consist of a single ply or multiple plies. In addition, the paper or tissue web can contain reinforcing fibers for integrity and strength.
[0025] The term “softening agent” refers to any chemical additive that can be incorporated into paper products such as tissue to provide improved tactile feel and reduce paper stiffness. A softening agent may be selected from the group consisting of quaternary ammonium compounds, quaternized protein compounds, phospholipids, polysiloxane compounds, quaternized, hydrolyzed wheat protein/dimethicone phosphocopolyol copolymer, organoreactive polysilxanes, polyhydroxy compounds, and silicone glycols. These chemical additives can also act to reduce paper stiffness or can act solely to improve the surface characteristics of tissue, such as by reducing the coefficient of friction between the tissue surface and the hand.
[0026] The term “dye” refers to any chemical that can be incorporated into paper products, such as bathroom tissue, facial tissue, paper towels, and napkins, to impart a color. Depending on the nature of the chemical, dyes may be classified as acid dyes, basic dyes, direct dyes, cellulose reactive dyes, or pigments. All classifications are suitable for use in conjunction with the present invention.
[0027] The term “polyhydroxy compounds” refers to compounds selected from the group consisting of glycerol, sorbitols, polyglycerols having a weight average molecular weight of from about 150 to about 800, polyoxyethylene glycols and polyoxypropylene glycols having a weight average molecular weight from typically about 200 to about 10,000, more typically about 200 to about 4,000.
[0028] The term “water soluble” refers to solids or liquids that will form a solution in water, and the term “water dispersible” refers to solids or liquids of colloidal size or larger that can be dispersed into an aqueous medium.
[0029] The term “bonding agent” refers to any chemical that can be incorporated into tissue to increase or enhance the level of interfiber or intrafiber bonding in the sheet. The increased bonding can be either ionic, Hydrogen or covalent in nature. It is understood that a bonding agent refers to both dry and wet strength enhancing chemical additives.
[0030] The method for applying chemical additives to the pulp fibers may be used in a wide variety of pulp finishing processing, including dry lap pulp, wet lap pulp, crumb pulp, and flash dried pulp operations. By way of illustration, various pulp finishing processes (also referred to as pulp processing) are disclosed in Pulp and Parer Manufacture: The Pulping of Wood, 2nd Ed., Volume 1, Chapter 12. Ronald G. MacDonald, editor, which is incorporated by reference. Various methods may be used to apply the chemical additives in the present invention, including, but not limited to: spraying, coating, foaming, printing, size pressing, or any other method known in the art.
[0031] In addition, in situations where more than one chemical additive is to be employed, the chemical additives may be added to the fibrous web in sequence to reduce interactions between the chemical additives.
[0032] Many pulp fiber types may be used for the present invention including hardwood or softwoods, straw, flax, milkweed seed floss fibers, abaca, hemp, kenaf, bagasse, cotton, reed, and the like. All known papermaking fibers may be used, including bleached and unbleached fibers, fibers of natural origin (including wood fiber and other cellulose fibers, cellulose derivatives, and chemically stiffened or crosslinked fibers), some component portion of synthetic fiber (synthetic papermaking fibers include certain forms of fibers made from polypropylene, acrylic, aramids, acetates, and the like), virgin and recovered or recycled fibers, hardwood and softwood, and fibers that have been mechanically pulped (e.g., groundwood), chemically pulped (including but not limited to the kraft and sulfite pulp processings), thermomechanically pulped, chemithermomechanically pulped, and the like. Mixtures of any subset of the above mentioned or related fiber classes may be used. The pulp fibers can be prepared in a multiplicity of ways known to be advantageous in the art. Useful methods of preparing fibers include dispersion to impart curl and improved drying properties, such as disclosed in U.S. Pat. Nos. 5,348,620 issued Sep. 20, 1994 and 5,501,768 issued Mar. 26, 1996, both to M. A. Hermans et al. and U.S. Pat. No. 5,656,132 issued Aug. 12, 1997 to Farrington, Jr. et al.
[0033] According to the present invention, the chemical treatment of the pulp fibers may occur prior to, during, or after the drying phase of the pulp processing. The two generally accepted methods of drying include flash drying, can drying, flack drying, through air drying, I.R. drying, fluidized bed, or any method of drying known in the art. The present invention may also be applied to wet lap pulp processes without the use of dryers.
[0034] Numerous features and advantages of the present invention will appear from the following description. In the description, reference is made to the accompanying drawings which illustrate preferred embodiments of the invention. Such embodiments do not represent the full scope of the invention. Reference should therefore be made to the claims herein for interpreting the full scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] [0035]FIG. 1 depicts a schematic process flow diagram of a method according to the present invention for treating pulp fibers with chemical additives.
[0036] [0036]FIG. 2 depicts a schematic process flow diagram of a method according to the present invention for treating pulp fibers with chemical additives.
[0037] [0037]FIG. 3 depicts a schematic process flow diagram of a method of making a creped tissue sheet.
[0038] [0038]FIG. 4 depicts a schematic process flow diagram of a method according to the present invention for treating pulp fibers with multiple chemical additives.
[0039] [0039]FIG. 5 depicts a schematic process flow diagram of a method according to the present invention for treating pulp fibers with multiple chemical additives.
DETAILED DESCRIPTION
[0040] The invention will now be described in greater detail with reference to the Figures. A variety of conventional pulping apparatuses and operations can be used with respect to the pulping phase, pulp processing, and drying of pulp fiber. It is understood that the pulp fibers could be virgin pulp fiber or recycled pulp fiber. Nevertheless, particular conventional components are illustrated for purposes of providing the context in which the various embodiments of the present invention can be used. Improved retention of chemical additives by the pulp fibers may be obtained by treating the pulp fibers according to the present invention rather than treating the pulp fibers in wet end additions at papermaking machines. In addition, the present invention allows for quick pulp fiber grade changes at the paper mills.
[0041] [0041]FIG. 1 depicts pulp processing preparation equipment used to apply chemical additives to pulp fibers according to one embodiment of the present invention. A fiber slurry 10 is prepared and thereafter transferred through suitable conduits (not shown) to the headbox 28 where the fiber slurry 10 is injected or deposited into a fourdrinier section 30 thereby forming a wet fibrous web 32 . The wet fibrous web 32 may be subjected to mechanical pressure to remove process water. It is understood that the process water may contain process chemicals used in treating the fiber slurry 10 prior to a web formation step. In the illustrated embodiment, the fourdrinier section 30 precedes a press section 44 , although alternative dewatering devices such as a nip thickening device, or the like may be used in a pulp sheet machine. The fiber slurry 10 is deposited onto a foraminous fabric 46 such that the fourdrinier section filtrate 48 is removed from the wet fibrous web 32 . The fourdrinier section filtrate 48 comprises a portion of the process water. The press section 44 or other dewatering device known in the art suitably increases the fiber consistency of the wet fibrous web 32 to about 30 percent or greater, and particularly about 40 percent or greater thereby creating a dewatered web 33 . The process water removed as fourdrinier section filtrate 48 during the web forming step may be used as dilution water for dilution stages in the pulp processing or discarded.
[0042] The dewatered fibrous web 33 may be further dewatered in additional press sections 44 or other dewatering devices known in the art. The suitably dewatered fibrous web 33 may be transferred to a dryer section 34 where evaporative drying is carried out on the dewatered fibrous web 33 to an airdry consistency, thereby forming a dried fibrous web 36 . The dried fibrous web 36 is thereafter wound on a reel 37 or slit, cut into sheets, and baled via a baler 40 (see FIG. 2) for delivery to paper machines 38 (see FIG. 3).
[0043] Chemical additive 24 may be added or applied to the dewatered fibrous web 33 or the dried fibrous web 36 at a variety of addition points 35 a , 35 b , and 35 c as shown in FIG. 1. It is understood that while only three addition points 35 a , 35 b , and 35 c are shown in FIG. 1, the application of the chemical additive 24 may occur at any point between the point of initial dewatering of the wet fibrous web 32 to the point the dried fibrous web 36 is wound on the reel 37 or baled for transport to the paper machines 38 . The addition point 35 a shows the addition of the chemical additive 24 within press section 44 . The addition point 35 b shows the addition of the chemical additive 24 between the press section 44 and the dryer section 34 . The addition point 35 c shows the addition of the chemical additive 24 between the dryer section 34 and the reel 37 or baler 40 .
[0044] A list of chemical additives that can be used in conjunction with the present invention include: dry strength agents, wet strength agents, softening agents, debonding agents, adsorbency agents, sizing agents, dyes, optical brighteners, chemical tracers, opacifiers, dryer adhesive chemicals, and the like. Additional chemical additives may include: pigments, emollients, humectants, viricides, bactericides, buffers, waxes, fluoropolymers, odor control materials and deodorants, zeolites, perfumes, vegetable and mineral oils, polysiloxane compounds, surfactants, moisturizers, UV blockers, antibiotic agents, lotions, fungicides, preservatives, aloe-vera extract, vitamin E, or the like. Suitable chemical additives are retained by the papermaking fibers and may or may not be water soluble or water dispersible.
[0045] At the paper machines 38 , (see FIG. 3) the dried fibrous web 36 is mixed with water to form a chemically treated pulp fiber slurry 49 . The chemically treated pulp fiber slurry 49 contains the chemically treated pulp fiber having the chemical additive 24 retained by the individual fibers. The chemically treated pulp fiber slurry 49 is passed through the paper machine 38 and processed to form a finished product 64 . By way of illustration, various paper or tissue making processes are disclosed in U.S. Pat. No. 5,667,636 issued Sep. 16, 1997 to Engel et al.; U.S. Pat. No. 5,607,551 issued Mar. 4, 1997 to Farrington, Jr. et al.; U.S. Pat. No. 5,672,248 issued Sep. 30, 1997 to Wendt et al.; and, U.S. Pat. No. 5,494,554 issued Feb. 27, 1996 to Edwards et al., which are incorporated herein by reference. The finished product 64 has enhanced qualities due to the retention of the chemical additive 24 by the chemically treated pulp fibers during the pulp processing. In other embodiments of the present invention, additional chemical additive 24 may be added to the chemically treated pulp fiber slurry 49 during stock preparation at the paper machine 38 .
[0046] [0046]FIG. 2 depicts an alternative embodiment of the present invention using a different dry lap machine to prepare and treat the pulp. A fiber slurry 10 is prepared and thereafter transferred through suitable conduits (not shown) to the headbox 28 where the fiber slurry 10 is injected or deposited into a fourdrinier section 30 thereby forming a wet fibrous web 32 . The wet fibrous web 32 may be subjected to mechanical pressure to remove process water. In the illustrated embodiment, the fourdrinier section 30 precedes a press section 44 , although alternative dewatering devices such as a nip thickening device, or the like known in the art may be used in a pulp sheet machine. The fiber slurry 10 is deposited onto a foraminous fabric 46 such that the fourdrinier section filtrate 48 is removed from the wet fibrous web 32 . The fourdrinier section filtrate 48 comprises a portion of the process water. The press section 44 or other dewatering device suitably increases the fiber consistency of the wet fibrous web 32 to about 30 percent or greater, and particularly about 40 percent or greater, thereby forming a dewatered fibrous web 33 . The process water removed as fourdrinier section filtrate 48 during the web forming step may be used as dilution water for dilution stages in the pulp processing or discarded.
[0047] The dewatered fibrous web 33 may be further dewatered in additional press sections 44 or other dewatering devices known in the art. The suitably dewatered fibrous web 33 may be transferred to a dryer section 34 where evaporative drying is carried out on the dewatered fibrous web 33 to an airdry consistency, thereby forming a dried fibrous web 36 . The dried fibrous web 36 is thereafter slit, cut into sheets, and baled via a baler 40 or wound on a reel 37 or wound onto a reel 37 (see FIG. 1) for delivery to paper machines 38 (see FIG. 3).
[0048] The chemical additive 24 may be added or applied to the dewatered fibrous web 33 or the dried fibrous web 36 at a variety of addition points 35 a , 35 b , and 35 c as shown in FIG. 2. It is understood that while only three addition points 35 a , 35 b , and 35 c are shown in FIG. 2, the application of the chemical additive 24 may occur at any point between the point of initial dewatering of the wet fibrous web 32 to the point the dried fibrous web 36 is wound on the reel 37 or baled for transport to the paper machines 38 . The addition point 35 a shows the addition of the chemical additive 24 within press section 44 . The addition point 35 b shows the addition of the chemical additive 24 between the press section 44 and the dryer section 34 . The addition point 35 c shows the addition of the chemical additive 24 between the dryer section 34 and the reel 37 or baler 40 .
[0049] At the paper machines 38 , (see FIG. 3) the dried fibrous web 36 is mixed with water to form a chemically treated pulp fiber slurry 49 . The chemically treated pulp fiber slurry 49 contains the chemically treated pulp fiber having the chemical additive 24 retained by the individual fibers. The chemically treated pulp fiber slurry 49 is passed through the paper machine 38 and processed to form a finished product 64 . By way of illustration, various paper or tissue making processes are disclosed in U.S. Pat. No. 5,667,636 issued Sep. 16, 1997 to Engel et al.; U.S. Pat. No. 5,607,551 issued Mar. 4, 1997 to Farrington, Jr. et al.; U.S. Pat. No. 5,672,248 issued Sep. 30, 1997 to Wendt et al.; and, U.S. Pat. No. 5,494,554 issued Feb. 27, 1996 to Edwards et al., which are incorporated herein by reference. The finished product 64 has enhanced qualities due to the retention of the chemical additive 24 by chemically treated the chemically treated pulp fibers during the pulp processing. In other embodiments of the present invention, additional chemical additive 24 may be added to the chemically treated pulp fiber slurry 49 during stock preparation at the paper machine 38 .
[0050] [0050]FIG. 4 depicts an alternative embodiment of the present invention in which sequential addition of the first and second chemical additives 24 and 25 , respectively, are added to the dewatered fibrous web slurry 33 and/or the dried fibrous web 36 . It is understood that the addition of the first chemical additive 24 may occur any where that the second chemical additive 25 may be applied. It is also understood that the addition of the second chemical additive 25 may occur any where that the first chemical additive 24 may be applied. A fiber slurry 10 is prepared and thereafter transferred through suitable conduits (not shown) to the headbox 28 where the fiber slurry 10 is injected or deposited into a fourdrinier section 30 thereby forming a wet fibrous web 32 . The wet fibrous web 32 may be subjected to mechanical pressure to remove process water. In the illustrated embodiment, the fourdrinier section 30 precedes a press section 44 , although alternative dewatering devices such as a nip thickening device, or the like known in the art may be used. The fiber slurry 10 is deposited onto a foraminous fabric 46 such that the fourdrinier section filtrate 48 is removed from the wet fibrous web 32 . The fourdrinier section filtrate 48 comprises a portion of the process water. The press section 44 or other dewatering device suitably increases the fiber consistency of the wet fibrous web 32 to about 30 percent or greater, and particularly about 40 percent or greater thereby forming a dewatered fibrous web 33 . The process water removed as fourdrinier section filtrate 48 during the web forming step may be used as dilution water for dilution stages in the pulp processing or discarded.
[0051] The dewatered fibrous web 33 may be further dewatered in additional press sections 44 or other dewatering devices known in the art. The suitably dewatered fibrous web 33 may be transferred to a dryer section 34 where evaporative drying is carried out on the dewatered fibrous web 33 to an airdry consistency, thereby forming a dried fibrous web 36 . The dried fibrous web 36 is thereafter wound on a reel 37 or slit, cut into sheets, and baled via a baler 40 (see FIG. 5) for delivery to paper machines 38 (see FIG. 3).
[0052] The first chemical additive 24 may be added or applied to the dewatered fibrous web 33 or the dried fibrous web 36 at a variety of addition points 35 a , 35 b , and 35 c as shown in FIG. 4. It is understood that while only three addition points 35 a , 35 b , and 35 c are shown in FIG. 4, the application of the first chemical additive 24 may occur at any point between the point of initial dewatering of the wet fibrous web 32 to the point the dried fibrous web 36 is wound on the reel 37 or baled for transport to the paper machines 38 . The addition point 35 a shows the addition of the first chemical additive 24 within press section 44 . The addition point 35 b shows the addition of the first chemical additive 24 between the press section 44 and the dryer section 34 . The addition point 35 c shows the addition of the first chemical additive 24 between the dryer section 34 and the reel 37 or baler 40 .
[0053] The second chemical additive 25 may be added or applied to the dewatered fibrous web 33 or the dried fibrous web 36 at a variety of addition points 35 a , 35 b , and 35 c as shown in FIG. 4. It is understood that while only three addition points 35 a , 35 b , and 35 c are shown in FIG. 4, the application of the second chemical additive 25 may occur at any point between the point of initial dewatering of the wet fibrous web 32 to the point the dried fibrous web 36 is wound on the reel 37 or baled for transport to the paper machines 38 downstream of at least the initial point of application of the first chemical additive 24 . The addition point 35 a shows the addition of the second chemical additive 25 within press section 44 . The addition point 35 b shows the addition of the second chemical additive 25 between the press section 44 and the dryer section 34 . The addition point 35 c shows the addition of the second chemical additive 25 between the dryer section 34 and the reel 37 or baler 40 .
[0054] At the paper machines 38 , (see FIG. 3) the dried fibrous web 36 is mixed with water to form a chemically treated pulp fiber slurry 49 . The chemically treated pulp fiber slurry 49 contains the chemically treated pulp fiber having the first and second chemical additives 24 and 25 retained by the individual fibers. The chemically treated pulp fiber slurry 49 is passed through the paper machine 38 and processed to form a finished product 64 . By way of illustration, various paper or tissue making processes are disclosed in U.S. Pat. No. 5,667,636 issued Sep. 16, 1997 to Engel et al.; U.S. Pat. No. 5,607,551 issued Mar. 4, 1997 to Farrington, Jr. et al.; U.S. Pat. No. 5,672,248 issued Sep. 30, 1997 to Wendt et al.; and, U.S. Pat. No. 5,494,554 issued Feb. 27, 1996 to Edwards et al., which are incorporated herein by reference. The finished product 64 has enhanced qualities due to the retention of the first and second chemical additives 24 and 25 by the chemically treated pulp fibers during the pulp processing. In other embodiments of the present invention, additional chemical additives may be added to the chemically treated pulp fiber slurry 49 during stock preparation at the paper machine 38 .
[0055] In other embodiments, it is understood that a third, fourth, fifth, so forth, chemical additives may be used to treat the dewatered fibrous web 33 and/or dried fibrous web 36 .
[0056] [0056]FIG. 5 depicts an alternative embodiment of the present invention in which sequential addition of the first and second chemical additives 24 and 25 , respectively, are added to the dewatered fibrous web slurry 33 and/or the dried fibrous web 36 . It is understood that the addition of the first chemical additive 24 may occur any where that the second chemical additive 25 may be applied. It is also understood that the addition of the second chemical additive 25 may occur any where that the first chemical additive 24 may be applied. A fiber slurry 10 is prepared and thereafter transferred through suitable conduits (not shown) to the headbox 28 where the fiber slurry 10 is injected or deposited into a fourdrinier section 30 thereby forming a wet fibrous web 32 . The wet fibrous web 32 may be subjected to mechanical pressure to remove process water. In the illustrated embodiment, the fourdrinier section 30 precedes a press section 44 , although alternative dewatering devices such as a nip thickening device, or the like known in the art may be used. The fiber slurry 10 is deposited onto a foraminous fabric 46 such that the fourdrinier section filtrate 48 is removed from the wet fibrous web 32 . The fourdrinier section filtrate 48 comprises a portion of the process water. The press section 44 or other dewatering device suitably increases the fiber consistency of the wet fibrous web 32 to about 30 percent or greater, and particularly about 40 percent or greater thereby forming a dewatered fibrous web 33 . The process water removed as fourdrinier section filtrate 48 during the web forming step may be used as dilution water for dilution stages in the pulp processing or discarded.
[0057] The dewatered fibrous web 33 may be further dewatered in additional press sections 44 or other dewatering devices known in the art. The suitably dewatered fibrous web 33 may be transferred to a dryer section 34 where evaporative drying is carried out on the dewatered fibrous web 33 to an air dry consistency, thereby forming a dried fibrous web 36 . The dried fibrous web 36 is thereafter slit, cut into sheets, and baled via a baler 40 or wound onto a reel 37 (see FIG. 4) for delivery to paper machines 38 (see FIG. 3).
[0058] The first chemical additive 24 may be added or applied to the dewatered fibrous web 33 or the dried fibrous web 36 at a variety of addition points 35 a , 35 b , and 35 c as shown in FIG. 4. It is understood that while only three addition points 35 a , 35 b , and 35 c are shown in FIG. 4, the application of the first chemical additive 24 may occur at any point between the point of initial dewatering of the wet fibrous web 32 to the point the dried fibrous web 36 is wound on the reel 37 or baled for transport to the paper machines 38 . The addition point 35 a shows the addition of the first chemical additive 24 within press section 44 . The addition point 35 b shows the addition of the first chemical additive 24 between the press section 44 and the dryer section 34 . The addition point 35 c shows the addition of the first chemical additive 24 between the dryer section 34 and the reel 37 or baler 40 .
[0059] The second chemical additive 25 may be added or applied to the dewatered fibrous web 33 or the dried fibrous web 36 at a variety of addition points 35 a , 35 b , and 35 c as shown in FIG. 5. It is understood that while only three addition points 35 a , 35 b , and 35 c are shown in FIG. 5, the application of the second chemical additive 25 may occur at any point between the point of initial dewatering of the wet fibrous web 32 to the point the dried fibrous web 36 is wound on the reel 37 or baled for transport to the paper machines 38 downstream of at least the initial point of application of the first chemical additive 24 . The addition point 35 a shows the addition of the second chemical additive 25 within press section 44 . The addition point 35 b shows the addition of the second chemical additive 25 between the press section 44 and the dryer section 34 . The addition point 35 c shows the addition of the second chemical additive 25 between the dryer section 34 and the reel 37 or baler 40 .
[0060] At the paper machines 38 , (see FIG. 3) the dried fibrous web 36 is mixed with water to form a chemically treated pulp fiber slurry 49 . The chemically treated pulp fiber slurry 49 contains the chemically treated pulp fiber having the first and second chemical additives 24 and 25 retained by the individual fibers. The chemically treated pulp fiber slurry 49 is passed through the paper machine 38 and processed to form a finished product 64 . By way of illustration, various paper or tissue making processes are disclosed in U.S. Pat. No. 5,667,636 issued Sep. 16, 1997 to Engel et al.; U.S. Pat. No. 5,607,551 issued Mar. 4, 1997 to Farrington, Jr. et al.; U.S. Pat. No. 5,672,248 issued Sep. 30, 1997 to Wendt et al.; and, U.S. Pat. No. 5,494,554 issued Feb. 27, 1996 to Edwards et al., which are incorporated herein by reference. The finished product 64 has enhanced qualities due to the retention of the first and second chemical additives 24 and 25 by the chemically treated pulp fibers during the pulp processing. In other embodiments of the present invention, additional chemical additives may be added to the chemically treated pulp fiber slurry 49 during stock preparation at the paper machine 38 .
[0061] In other embodiments, it is understood that a third, fourth, fifth, so forth, chemical additives may be used to treat the dewatered fibrous web 33 and/or dried fibrous web 36 .
[0062] The amount of first chemical additive 24 is suitably about 0.1 kg./metric ton of pulp fiber or greater. In particular embodiments, wherein the first chemical additive 24 is a softening agent and is added in an amount from about 0.1 kg./metric ton of pulp fiber or greater.
[0063] The amount of the second chemical additive 25 is suitably about 0.1 kg./metric ton of pulp fiber or greater. In particular embodiments, wherein the second chemical additive 25 is a softening agent and is added in an amount from about 0.1 kg./metric ton of pulp fiber or greater.
[0064] In other embodiments of the present invention, each of the first and second chemical additives 24 and 25 may be added to the fiber slurry 10 at a variety of positions in the pulp processing apparatus.
[0065] In other embodiments of the present invention, one batch of pulp fibers may be treated with a first chemical additive 24 according to the method of the present invention as discussed above while a second batch of pulp fibers may be treated with a second chemical additive 25 according to the present invention. During the papermaking process, different pulp fibers or pulp fibers having different treatments may be processed into a layered paper or tissue product as disclosed in the U.S. Pat. No. 5,730,839 issued Mar. 24, 1998 to Wendt et al., which is incorporated herein by reference.
[0066] Referring to the FIG. 3, a tissue web 64 is formed using a 2-layer headbox 50 between a forming fabric 52 and a conventional wet press papermaking (or carrier) felt 56 which wraps at least partially about a forming roll 54 and a press roll 58 . The tissue web 64 is then transferred from the papermaking felt 56 to the Yankee dryer 60 applying the vacuum press roll 58 . An adhesive mixture is typically sprayed using a spray boom 59 onto the surface of the Yankee dryer 60 just before the application of the tissue web to the Yankee dryer 60 by the press roll 58 . A natural gas heated hood (not shown) may partially surround the Yankee dryer 60 , assisting in drying the tissue web 64 . The tissue web 64 is removed from the Yankee dryer by the creping doctor blade 62 . Two tissue webs 64 may be plied together and calendered. The resulting 2-ply tissue product can be wound onto a hard roll.
[0067] In other embodiments of the present invention, a gradient of the first and/or the second chemical additives 24 and 25 along the z-direction of the dewatered fibrous web 33 and/or the dried fibrous web 36 may be established by a directed application of the first and/or the second chemical additives 24 and 25 . In one embodiment, the first and/or the second chemical additives 24 and 25 are applied to one side of the dewatered fibrous web 33 and/or the dried fibrous web 36 . In another embodiment, one side of the dewatered fibrous web 33 and/or the dried fibrous web 36 is saturated with the first and/or the second chemical additives 24 and 25 . In another embodiment, a dual gradient may be established in the z-direction of the dewatered fibrous web 33 and/or the dried fibrous web 36 by applying the first chemical additive 24 to one side of the dewatered fibrous web 33 and/or the dried fibrous web 36 and applying the second chemical additive 25 to the other (opposing) side of the dewatered fibrous web 33 and/or the dried fibrous web 36 . The term “z-direction” refers to the direction through the thickness of the web material.
[0068] The first and/or the second chemical additives 24 and 25 may be applied so as to establish a gradient wherein about 100 percent of each of the first and/or the second chemical additives 24 and 25 is located from the side of the dewatered fibrous web 33 and/or the dried fibrous web 36 treated with the first and/or the second chemical additives 24 and 25 to the middle of the dewatered fibrous web 33 and/or the dried fibrous web 36 along the z-direction of the dewatered fibrous web 33 and/or the dried fibrous web 36 and substantially none of each of the first and/or the second chemical additives 24 and 25 is located from the middle of the dewatered fibrous web 33 and/or the dried fibrous web 36 to the opposing side of the dewatered fibrous web 33 and/or the dried fibrous web 36 along the z-direction of the dewatered fibrous web 33 and/or the dried fibrous web 36 .
[0069] The first and/or the second chemical additives 24 and 25 may be applied so as to establish a gradient wherein about 66 percent of each of the first and/or the second chemical additives 24 and 25 is located from the side of the dewatered fibrous web 33 and/or the dried fibrous web 36 treated with the first and/or the second chemical additives 24 and 25 to the middle of the dewatered fibrous web 33 and/or the dried fibrous web 36 along the z-direction of the dewatered fibrous web 33 and/or the dried fibrous web 36 and about 33 percent of each of the first and/or the second chemical additives 24 and 25 is located from the middle of the dewatered fibrous web 33 and/or the dried fibrous web 36 to the opposing side of the dewatered fibrous web 33 and/or the dried fibrous web 36 along the z-direction of the dewatered fibrous web 33 and/or the dried fibrous web 36 .
[0070] It is understood that in any of these embodiments, the first and second chemical additives 24 and 25 may be each applied an opposing side of the dewatered fibrous web 33 and/or the dried fibrous web 36 . Alternatively, the first and second chemical additives 24 and 25 could be applied to both opposing sides of the dewatered fibrous web 33 and/or the dried fibrous web 36 . In still another variation, the first and second chemical additives 24 and 25 could be applied to only one side of the dewatered fibrous web 33 and/or the dried fibrous web 36 . Where only a first chemical additive 24 is applied to the dewatered fibrous web 33 and/or the dried fibrous web 36 , the first chemical additive 24 may be applied to one side or both opposing sides of the dewatered fibrous web 33 and/or the dried fibrous web 36
[0071] The first and/or the second chemical additives 24 and 25 may be applied so as to establish a gradient wherein about 60 percent of each of the first and/or the second chemical additives 24 and 25 is located from the side of the dewatered fibrous web 33 and/or the dried fibrous web 36 treated with the first and/or the second chemical additives 24 and 25 to the middle of the dewatered fibrous web 33 and/or the dried fibrous web 36 along the z-direction of the dewatered fibrous web 33 and/or the dried fibrous web 36 and about 40 percent of each of the first and/or the second chemical additives 24 and 25 is located from the middle of the dewatered fibrous web 33 and/or the dried fibrous web 36 to the opposing side of the dewatered fibrous web 33 and/or the dried fibrous web 36 along the z-direction of the dewatered fibrous web 33 and/or the dried fibrous web 36 .
[0072] In another embodiment of the present invention, the amounts of the first and/or second chemical additives 24 and 25 may be reduced to impart unique product characteristics due to the distribution of the first and/or second chemical additives 24 and 25 of the dewatered fibrous web 33 and/or the dried fibrous web 36 as opposed to an embodiment of the present invention wherein an equilibrated distribution of the first and/or second chemical additives 24 and 25 of the dewatered fibrous web 33 and/or the dried fibrous web 36 . The establishment of a gradient of the application of the first and/or the second chemical additives 24 and 25 of the dewatered fibrous web 33 and/or the dried fibrous web 36 is one way in which this may be accomplished. A directed application of a debonding chemical additive according to the present invention results in a reduced amount of the debonding chemical additive which produces a product having improved tensile strength as some of the pulp fiber is not treated by the debonding chemical additive.
EXAMPLES
[0073] The following example will describe how to produce chemically treated pulp as described according to the present invention. In these examples the definition of applied refers to the amount of chemical measured to be on the dry fiber mat after treatment. This amount is determined through measurement of chemical described in the Measurement Methods section.
[0074] Chemical retention in these examples is defined as the percentage of applied chemical treatment that remains with the fiber after the treated mat is redispersed to a low percent solids content in hot water. The percent retention was calculated according to Equation 1.
% R = C f - C w S ρ C f ( 100 % ) Equation 1
[0075] where % R is the chemical retention C f is the measured chemical level applied to pulp in units of kg/MT C w is the measured chemical level in the redispersed treated pulp water phase in units of mg/L S is the solids content of redispersed treated pulp in units of g fiber/g slurry ρ is the density of the pulp water slurry in units of g/L (typically 1000 g/L for dilute solutions)
MEASUREMENT METHODS
[0076] Imidazoline concentrations were measured in water by using a DR/2010 Portable Datalogging Spectrophotometer commercially available from Hach Company, located in Loveland, Colo. The spectrophotometer method #401 for Quaternary Ammonium Compounds was employed using suitable blanks and dilution. Imidazoline concentrations were measured on fiber using a liquid extraction procedure consisting of oven-drying the pulp for 4 hours at 105° C.; weighing out 5 g of pulp and placing it in 100 mL of anhydrous methanol in a 125 mL container. The pulp-methanol was then placed in a Lab-line model 3590 orbital shaker bath, commercially available from Lab-line Instruments Melrose Park, Ill., which was operated at 300 rpm for 2 hours. An aliquot of the liquid sample absorbance was then measured at 238 nm on a Hewlett Packard model 8453 UVNIS spectrophotometer, commercially available from Hewlett Packard Company, located in Palo Alto, Calif. This value was used with a prepared calibration curve using the identical procedure with imidazoline spiked samples.
EXAMPLE 1
[0077] The untreated pulp in this example is a fully bleached eucalyptus pulp fiber slurry with a pH value of 4.5. Referencing FIG. 1, this fiber was formed into a mat a basis weight of approximately 600 grams per square meter, pressed and dried to 95 percent solids. Next, a 4 percent (active content basis) water dispersion of imidazoline softening agent (methyl-1-oleyl amidoethyl-2-oleyl imidazolinium methylsulfate identified as Mackernium DC-183, commercially available from McIntyre Ltd., located in University Park, Ill.), was sprayed on the surface of the fiber mat. The dispersion was created by mixing the imidazoline compound with water at approximately 120° F. for 10 minutes with a Lightnin Duramix mixer with an A100 axial flow impeller commercially available from Lightnin Mixers, located in Rochester, N.Y. The spray was applied using 7 mini-misting hollow cone nozzles with an 80 degree spray angle available from McMaster-Carr. The nozzles were place 5 inches center-to-center, 2.5 inches away from the sheet. The nozzles were aligned to spray perpendicular to the sheet applying single coverage. The nozzles were positioned approximately 5 feet after the dryer section. Each nozzle's output was adjusted approximately 40 milliliters per minute of the imidazoline-water dispersion by adjusting the dispersion feed pressure to 40 psig.
[0078] The amount of the chemical softener applied to the mat was approximately 3 kilograms per metric ton of eucalyptus fiber. The chemical softener was allowed to remain on the pulp mat for 2 weeks after which it was dispersed to approximately 1.6 percent solids with hot water at 120° F. Samples from this treatment were taken and used to determine the amount of chemical softener that remained in the water phase, which was drained as filtrate from the pulp fiber. The concentrations of the aqueous chemical softener levels were converted into a percent retention basis. The chemical softener retention level is shown in Table 1.
EXAMPLE 2
[0079] Identical to Example 1 with the exception that the eucalyptus slurry pH was adjusted to a pH value of 7. The chemical softener retention level is shown in Table 1.
EXAMPLE 3
[0080] The untreated pulp in this example is a fully bleached eucalyptus pulp fiber slurry with a pH value of 4.5. Referencing FIG. 1, this fiber was formed into a mat a basis weight of 900 grams oven-dry pulp per square meter, pressed and dried to 95 percent solids. Next, a 5 percent (active content basis) water dispersion of imidazoline softening agent (methyl-1-oleyl amidoethyl-2-oleyl imidazolinium methylsulfate identified as Mackernium DC-183, commercially available from McIntyre Ltd., located in University Park, Ill.), was sprayed onto the surface of the fiber mat. The dispersion was created by mixing the imidazoline compound with water at approximately 120° F. for 10 minutes with a Lightnin Duramix mixer with an A100 axial flow impeller commercially available from Lightnin Mixers, located in Rochester, N.Y. The spray was applied using 15 mini-misting hollow cone nozzles with an 80 degree spray angle available from McMaster-Carr. The nozzles were place 2.5 inches center-to-center, 1.5 inches away from the sheet. The nozzles were aligned to spray perpendicular to the sheet applying single coverage. The nozzles were positioned approximately 5 feet after the dryer section. Each nozzle's output was adjusted to approximately 55 milliliters per minute of the imidazoline-water dispersion by adjusting the dispersion feed pressure to 60 psig.
[0081] The amount of the chemical softener applied to the mat was approximately 7.5 kilograms per metric ton of eucalyptus fiber. The chemical softener was allowed to remain on the pulp mat for 2 weeks after which it was dispersed to approximately 1.6 percent solids with hot water at 120° F. Samples from this treatment were taken and used to determine the amount of chemical softener that remained in the water phase, which was drained as filtrate from the pulp fiber. The concentrations of the aqueous chemical softener levels were converted into a percent retention basis. The aqueous chemical softener retention level is shown in Table 1.
EXAMPLE 4
[0082] The untreated pulp in this example is a fully bleached eucalyptus pulp fiber slurry with a pH value of 4.5. Referencing FIG. 1, this fiber was formed into a mat at a basis weight of 600 grams per square meter, and pressed to 45% solids after which a 4 percent dispersion of an imidazoline softening agent (methyl-1-oleyl amidoethyl-2-oleyl imidazolinium methylsulfate identified as Mackernium DC-183), was sprayed unto the surface of the fiber mat. The nozzles were positioned approximately 1 foot prior to the second press. Chemical softener was applied at approximately 1.5 kg/MT in this manner after which the pulp sheet was dried to approximately 95 percent solids.
[0083] The chemical softener was allowed to remain on the pulp mat for 2 weeks after which it was dispersed to approximately 1.6 percent solids with hot water at 120 ° F. Samples from this treatment were taken and used to determine the amount of chemical softener that remained in the water phase, which was drained as filtrate from the pulp fiber. The concentrations of the aqueous chemical softener levels were then converted into a percent retention basis. The chemical softener retention level is shown in Table 1 .
EXAMPLE 5
[0084] Identical to Example 4 with the exception that the eucalyptus slurry was adjusted to a pH value of 7.0. The aqueous chemical softener retention level is shown in Table 1.
EXAMPLE 6
[0085] The untreated pulp in this example is a fully bleached eucalyptus pulp fiber slurry with a pH value of 4.5. Referencing FIG. 1, this fiber was formed into a mat at a basis weight of 900 grams per square meter, and pressed to 60% solids after which a 4 percent dispersion of an imidazoline softening agent (methyl-1-oleyl amidoethyl-2-oleyl imidazolinium methylsulfate identified as Mackern ium DC-183), was sprayed unto the surface of the fiber mat. The nozzles were positioned approximately 3 feet before the dryer section. Chemical softener was applied at approximately 7.5 kg/MT in this manner after which the pulp sheet was dried to 95 percent solids.
[0086] The chemical softener was allowed to remain on the pulp mat for 2 weeks after which it was dispersed to approximately 1.6 percent solids with hot water at 120° F. Samples from this treatment were taken and used to determine the amount of chemical softener that remained in the water phase, which was drained as filtrate from the pulp fiber. The concentrations of the aqueous chemical softener levels were then converted into a percent retention basis. The aqueous chemical softener retention level is shown in Table 1.
EXAMPLE 7
[0087] The untreated pulp in this example is a fully bleached eucalyptus pulp fiber slurry with a pH value of 4.5. Referencing FIG. 2, this fiber was formed into a mat a basis weight of approximately 1000 grams per square meter, pressed and dried to 90 percent solids, after which a 4 percent dispersion of an imidazoline softening agent (methyl-1-oleyl amidoethyl-2-oleyl imidazolinium methylsulfate identified as Mackernium DC-183), was sprayed on the surface of the fiber mat. The spray was applied using 21 Veejet HVV 11004 nozzles with a 110 degree spray angle available from Spraying Systems, located in Wheaton, Ill. The nozzles were place 8.1 inches center-to-center, 1.5 inches away from the sheet. The nozzles were aligned to spray perpendicular to the sheet applying single coverage. The nozzles were positioned approximately 10 feet after the dryer section. Each nozzle's output was adjusted to approximately 500 milliliters per minute of the imidazoline-water dispersion by adjusting the dispersion feed pressure to 35 psig. The fiber mat's velocity was approximately 500 meters per minute during the application.
[0088] The amount of the chemical softener applied to the mat was approximately 2 kilograms per metric ton of eucalyptus fiber. The chemical softener was allowed to remain on the pulp mat for 3 weeks after which it was dispersed to approximately 8.5 percent solids with hot water at 120° F. Samples from this treatment were taken and used to determine the amount of chemical softener that remained in the water phase, which was drained as filtrate from the pulp fiber. The concentrations of the aqueous chemical softener levels were converted into a percent retention basis. The chemical softener retention level is shown in Table 1.
EXAMPLE 8
[0089] Identical to Example 7 with the exceptions that the eucalyptus slurry pH was adjusted to a pH value of 7, the chemical softening agent was applied at a 1.5 kg/MT level, and the pulp was redispersed at 2.5 percent solids. The chemical softener retention level is shown in Table 1.
TABLE 1 Aqueous Chemical Softener Levels Chemical Softener Chemical Chemical Application Pre-treated Application Level Softener Sample Softener location pulp pH (kg/MT fiber) Retention (%) Example 1 Imidazoline Post-dryer 4.5 3.2 87.9% Emulsion Example 2 Imidazoline Post-dryer 7.0 3.2 87.8% Emulsion Example 3 Imidazoline Post-dryer 4.5 7.4 78.8% Emulsion Example 4 Imidazoline Press- 4.5 1.5 91.2% Emulsion section Example 5 Imidazoline Press- 7.0 1.5 91.6% Emulsion section Example 6 Imidazoline Pre-dryer 4.5 7.4 86.0% Emulsion Example 7 Imidazoline Post-dryer 4.5 1.9 99.5% Emulsion Example 8 Imidazoline Post-dryer 7.0 1.6 87.3% Emulsion
EXAMPLE 9
[0090] The chemically treated eucalyptus pulp in Example 1 was used to produce a layered soft tissue product. The tissue product was made using the overall process shown in FIG. 3. The first stock layer contained the chemically treated Eucalyptus hardwood pulp fiber, which made up about 65 percent of the tissue web by weight. This first stock layer was the first layer to come into contact with the forming fabric and was also the layer that came into contact with the drying surface of the Yankee dryer. The second stock layer contained northern softwood kraft pulp fiber. The second stock layer made up about 35 percent of the tissue web by weight. The two layers were pressed together at an approximately 15% solids vacuumed, pressed, and dried with a Yankee Dryer.
[0091] A modified polyacrylamide dry strength agent, Parez 631 NC commercially available from Cytec Industries Inc. located in West Paterson, N.J., was added to the pulp fiber of the softwood layer. The Parez 631 NC was added to the thick stock at an addition level of about 0.2% of the pulp fiber in the entire tissue web. A polyamide epichlorohydrin wet strength agent, Kymene 557LX commercially available from the Hercules, Inc., located in Wilmington, Del., was added to both the Eucalyptus and northern softwood kraft furnishes at an addition level of about 0.2% based on the pulp fiber in the entire tissue web.
[0092] The basis weight of the tissue web was about 7.0 pounds per 2880 square feet of oven dried tissue web.
[0093] Referring to the FIG. 3, the tissue web was formed using 2 separate headboxes with a 94M forming fabric commercially available from Albany International, located in Albany, N.Y., and a conventional wet press papermaking (or carrier) felt (Duramesh commercially available from from Albany International, located in Albany, N.Y.) which wraps at least partially about a forming roll and a press roll. The basis weight of the tissue web was about 7.0 pounds per 2880 square feet of oven dried tissue web.
[0094] The tissue web was then transferred from the papermaking felt to the Yankee dryer by the press roll. The water content of the tissue web on the papermaking felt just prior to transfer of the tissue web to the Yankee dryer was about 80 percent. The moisture content of the tissue web after the application of the press roll was about 55 percent. An adhesive mixture was sprayed using a spray boom onto the surface of the Yankee dryer just before the application of the tissue web by the press roll. The adhesive mixture consisted of about 40% polyvinyl alcohol, about 40% polyamide resin and about 20% quaternized polyamido amine as disclosed in U.S. Pat. No. 5,730,839 issued to Wendt et al. which is herein incorporated by reference. The application rate of the adhesive mixture was about 6 pounds of dry adhesive per metric ton of dry pulp fiber in the tissue web. A natural gas heated hood partially surrounding the Yankee dryer had a supply air temperature of about 680° F. to assist in drying the tissue web. The temperature of the tissue web after the application of the creping doctor was about 225° F. as measured with a handheld infrared temperature gun. The machine speed of the X inch wide tissue web was about 50 feet per minute. The crepe blade had a 10 degree bevel and was loaded with a % inch extension. The crepe ratio was about 1.30 or about 30%.
EXAMPLE 10
[0095] Identical to Example 9 with the exception that chemically treated eucalyptus pulp in Example 2 was used to produce a layered soft tissue product.
EXAMPLE 11
[0096] Identical to Example 10 with the exception that chemically treated eucalyptus pulp in Example 3 was used to produce a layered soft tissue product.
EXAMPLE 12
[0097] Identical to Example 11 with the exception that chemically treated eucalyptus pulp in Example 4 was used to produce a layered soft tissue product.
EXAMPLE 13
[0098] Identical to Example 12 with the exception that chemically treated eucalyptus pulp in Example 5 was used to produce a layered soft tissue product.
EXAMPLE 14
[0099] Identical to Example 13 with the exception that chemically treated eucalyptus pulp in Example 6 was used to produce a layered soft tissue product.
EXAMPLE 15
[0100] The chemically treated eucalyptus pulp in Example 7 was used to produce a layered soft tissue product. The tissue product was made using the overall process shown in FIG. 3. The first stock layer contained the chemically treated Eucalyptus hardwood pulp fiber, which made u p about 65 percent of the tissue web by weight. This first stock layer was the first layer to come into contact with the forming fabric and was also the layer that came into contact with the drying surface of the Yankee dryer. The second stock layer contained northern softwood kraft pulp fiber. The second stock layer made up about 35 percent of the tissue web by weight. A polyamide epichlorohydrin wet strength agent, Kymene 557LX commercially available from the Hercules, Inc., was added to both the Eucalyptus and northern softwood kraft furnishes at an addition level of about 0.2% based on the pulp fiber in the entire tissue web. The basis weight of the tissue web was approximately 7.0 pounds per 2880 square feet of oven dried tissue web.
[0101] Referring to the FIG. 3 the tissue web was formed using a 2-layer headbox between an Albany P-621 forming fabric commercially available from Albany International Corp., located in Menasha, Wis., and a conventional wet press papermaking (or carrier) felt (Weavex M1C commercially available from Weavex located in Wake Forest, N.C.) which wraps at least partially about a forming roll and a press roll. The basis weight of the tissue web was about 7.0 pounds per 2880 square feet of oven dried tissue web.
[0102] The tissue web was then transferred from the papermaking felt to the Yankee dryer by the vacuum press roll. The water content of the tissue web on the papermaking felt just prior to transfer of the tissue web to the Yankee dryer was about 87 percent. The moisture content of the tissue web after the application of the press roll was about 55 percent. An adhesive mixture was sprayed using a spray boom onto the surface of the Yankee dryer just before the application of the tissue web by the press roll. The adhesive mixture consisted of about 40% polyvinyl alcohol, about 40% polyamide resin and about 20% quaternized polyamido amine as disclosed in U.S. Pat. No. 5,730,839 issued to Wendt et al. which is herein incorporated by reference. The application rate of the adhesive mixture was about 5.5 pounds of dry adhesive per tonne of dry pulp fiber in the tissue web. A natural gas heated hood (not shown) partially surrounding the Yankee dryer had a supply air temperature of about 680° F. to assist in drying the tissue web. The temperature of the tissue web after the application of the creping doctor was about 240° F. as measured with a handheld infrared temperature gun. The machine speed of the 24 inch wide tissue web was about 3000 feet per minute. The crepe ratio was about 1.30 or about 30%.
[0103] Two tissue webs were unwound from two soft rolls (or parent rolls) and plied together and calendered with two steel rolls at 80 pounds per lineal inch. The 2-ply tissue product was constructed such that the first stock layer containing the chemically treated Eucalyptus pulp fiber was plied to the outside of the 2-ply tissue product, which was wound onto a hard roll. The hard roll is converted into finished product, such as facial tissue and the like. The finished basis weight of the 2-ply tissue product at standard TAPPI standard temperature and humidity was about 17 pounds per 2880 square feet. The MD tensile was about 1100 grams per 3 inches and the CD tensile was about 500 grams per 3 inches. The thickness of one 2-ply tissue product was about 0.2 millimeters. The MD stretch in the finished tissue product was about 18 percent. All 2-ply tissue tests were conducted in an environmentally controlled room with 50% relative humidity and a temperature of 73° F.
EXAMPLE 16
[0104] Identical to Example 15 with the exception that chemically treated eucalyptus pulp in Example 8 was used to produce a layered soft tissue product.
[0105] While the invention has been described in conjunction with specific embodiments, it is to be understood that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, this invention is intended to embrace all such alternatives, modifications and variations which fall within the spirit and scope of the appended claims.
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Pulp fibers can be treated with chemical additives with a minimal amount of unretained chemical additives present later in the process water. The present invention is a method for preparing chemically treated pulp fiber. A fiber slurry is created comprising process water and pulp fibers. The fiber slurry is transported to a web-forming apparatus of a pulp sheet machine thereby forming a wet fibrous web. The wet fibrous web is dried to a predetermined consistency thereby forming a dried fibrous web. The dried fibrous web is treated with a chemical additive thereby forming a chemically treated dried fibrous web. The dried fibrous web contains chemically treated pulp fibers. The chemically treated pulp fibers retain from between about 10 to about 100 percent of the applied amount of the chemical additive when the chemically treated pulp fibers are redispersed in water.
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BACKGROUND OF THE INVENTION
In the papermaking industry and the personal care field, it is common practice and well known to fiberize various cellulosic feedstocks for a variety of purposes. For example, in manufacturing airlaid tissue products, it is necessary to first reduce pulp sheets to individual fibers prior to depositing the fibers onto a forming wire. In the infant care and feminine care areas, pulp sheets are fiberized for making fluff for diapers and feminine products.
Many different types of apparatus are available for these purposes which can generally be classified into two categories, namely fiberizers and formers. Fiberizers, such as hammermills, serve to fiberize crude feedstocks, such as pulp sheets and waste paper, breaking down these feedstocks into a loose fibrous mass and individual fibers. On the other hand, formers are generally fed individual fibers or loosely bound fiber batts produced by a fiberizer and serve to lay the fibers evenly on a forming wire. There may be some overlap in the function of any given apparatus in that formers may accomplish some fiberization and fiberizers may be used to lay down fibrous batts. But all the different types of apparatus used for processing fibers share the common function of expelling individual fibers through an outlet while preferably retaining any clumps, nits, pills, or the like within the apparatus until they are sufficiently broken down or expelled through a separate recycle orifice. This is accomplished within a chamber enclosing arcuately travelling impact elements, such as blades or hammers, which thrust the fibers or fibrous material against the inner surface of the chamber. A portion of this inner surface contains an outlet having a large number of orifices through which small particles and individual fibers pass as the product of the apparatus. In the case of fiberizers and some formers, these orifices generally consist of holes drilled through the wall of the inner surface. In other formers, these orifices can also be mesh openings in a screen.
A problem which inevitably occurs with all prior apparatus of this type is that the outlet orifices become plugged with fibers at some level of throughout capacity, i.e. the throughput of the apparatus can be increased only so far, at which point it becomes plugged. Oftentimes this capacity limit is reached at an unacceptably low level of throughput. The apparatus illustrated in U.S. Ser. No. 4,375,447 to Chung and U.S. Pat. No. 4,375,448 to Appel et al utilize a slotted screen to overcome these problems, but the use of a woven screen still presents plugging problems, even if the screen openings are elongated rather than square.
Therefore, there exists a need for an apparatus for processing fibers which minimizes or inhibits plugging of the outlet orifices and therefore is capable of higher throughput capacity.
SUMMARY OF THE INVENTION
In general, the invention resides in an apparatus for processing fibers or fibrous materials having arcuately travelling impact elements enclosed within a chamber by an internal surface arcuately spaced apart from said impact elements, wherein said chamber contains an outlet having a multiplicity of openings through which fibers leave the apparatus, the improvement comprising an outlet consisting essentially of a plurality of spaced-apart dividers aligned in a direction perpendicular to the direction of travel of the impact elements and having a leading surface or portion thereof which is inwardly slanted in the direction of travel of the impact elements, said dividers being separated by continuous or semi-continuous slots. It has been discovered that by designing the chamber outlet in this manner, plugging problems are greatly reduced and throughput capacity is increased.
For purposes herein, the term "apparatus" is intended to include fiberizers and formers unless otherwise stated. The term "impact element" is a general term referring to the extremity of any rotating element within the apparatus serving to move fibers or fibrous materials around the periphery of the chamber including, without limitation, blades as used in formers and hammers as used in hammermills. The term "continuous slot" means an uninterrupted elongated opening in the outlet that extends the width of the apparatus. The term "semi-continuous slot" means a continuous slot which has a minimal number of surface interruptions connecting opposite sides of the slot. Semi-continuous slots may be a necessity if the width of the apparatus is sufficient to require structural support between opposite sides of the slots at certain intervals. The adverse effects caused by the presence of such structural supports can be minimized if the supports are located sufficiently below the innermost edge of the divider to avoid interfering with fiber passage into the outlet. The term "direction of travel of the impact element" refers to a vector representing the instantaneous or tangential direction of travel of a particular impact element relative to a given point when the impact element is positioned as close to the given point as possible. Accordingly, the direction of travel of an impact element is different for each point on the internal surface falling along the arcuate path of the impact element. This concept is further discussed in connection with FIG. 4.
It has been discovered that in an apparatus which uses a screen for the outlet of the chamber, one of the mechanisms of plug formation is for individual fibers to drape themselves over the wires running in direction of travel of the impact elements. The air currents in the apparatus cause the draped fiber to slide in the direction of travel of the impact element until it contacts a wire oriented in the perpendicular direction, where it becomes lodged into the crevice formed by the intersecting wires. This occurrence repeats itself with different fibers until enough fibers collect to plug the orifice. It has been noted that very little plugging is due to the fibers draping themselves over one of the wires which run perpendicular to the direction of travel of the impact element. This is apparently because the air currents created by the impact elements urge any such fibers to continue to move in the direction of travel of the impact elements, thereby eventually working the fibers free of the wire.
The apparatus of this invention takes advantage of this discovery by eliminating, to the extent possible taking structural limitations into account, all or most of any solid surfaces within the outlet which are oriented parallel to the direction of travel of the passing impact elements. Hence the dividers of this invention within the outlet are aligned or oriented generally perpendicularly to the direction of travel of the impact elements and they are separated by continuous or semi-continuous slots.
In addition, another reason for the improved performance of the apparatus of this invention is that the leading surface of the inner edge of the dividers is inclined in the direction of travel of the passing impact elements. With this arrangement, aggregates of fibers which approach the outlet strike the leading surfaces of the dividers and deflect back into the chamber to be further fiberized or recycled rather than plugging or passing through the slot. Hence the apparatus of this invention serves to classify fibers or agglomerates according to their mass:surface area ratio. The heavier aggregates have sufficient momentum to deflect off the leading surface, while the lighter individual fibers and aggregates can follow the air currents into the slot.
The operation of the apparatus of this invention will be described in greater detail by reference to the Drawing.
cl BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows a cross-sectional view of an apparatus for processing fibers having an outlet in accordance with this invention.
FIGS. 2A and 2B show plan views of a wire screen being used in a prior art outlet illustrating plug formation resulting from individual fibers draping over wires oriented in the direction of travel of the impact element.
FIG. 3 shows a perspective view of a segment of the outlet of an apparatus in accordance with this invention.
FIG. 4 shows a cross-sectional view of the outlet of the apparatus of FIG. 3.
FIG. 5 shows a cross-sectional view similar to FIG. 4, illustrating an alternative design for the construction of the outlet in accordance with this invention.
FIG. 6 shows a cross-sectional view similar to FIG. 5, illustrating another alternative for the outlet in accordance with this invention.
FIG. 7 shows still another alternative embodiment of the outlet similar to those shown in FIGS. 4, 5, and 6.
DETAILED DESCRIPTION OF THE INVENTION
Directing attention FIG. 1, the invention will be described in greater detail. In order to provide a proper setting for the following Figures, FIG. 1 generally shows a cross-sectional view of an apparatus of this invention having a feed inlet, arcuately travelling impact elements 1 which travel along an arcuate path 2, and an outlet, generally designated by reference numberal 3, disposed within a chamber defined by the internal surface 4 of the apparatus. Although not shown, the internal surface can contain protrusions and depressions for the purpose of fiberizing the feed material. The outlet suitably contains supported spaced-apart metal plates 5 (dividers) through which fiberized materials leave the apparatus. Any number of plates can be used as desired for optimal throughput. The relative positions of the feed inlet and the outlet 3 can vary depending on the specific application. For example, if the feed were to be partially fiberized materials, the inlet could be as close to the outlet as is practical. On the other hand, if the feed were to be large pieces of materials such as keypunch cards, ledger paper, etc., then locating the outlet as far from the inlet as possible (as shown) is preferred in order to give the apparatus sufficient opportunity to complete the fiberization by working the material against the entire periphery of the internal surface of the apparatus. Also shown in FIG. 1 is dashed line 25 which is an imaginary extension of the internal surface 4.
FIGS. 2A and 2B illustrate how fibers are believed to clog a prior art apparatus which has an outlet containing a wire screen as previously discussed. Shown is the wire mesh screen 7, a fiber 8 which is draped or stapled across a wire 9 which is aligned parallel to the direction of travel of the impact elements as indicated by arrow 2. Also shown is another fiber 11 which is draped or stapled across a wire 12 aligned perpendicularly to the direction of travel of the impact elements. The operation of the apparatus illustrated in FIGS. 2A and 2B is such that the individual fibers are intended to leave the apparatus through the mesh openings in the screen by passing into the plane of the paper. As shown in FIG. 2A, fibers 8 and 11 have initially been draped over wires 9 and 12, respectively. Because of the air currents generated by the impact elements as they sweep past the surface of the screen 7, both fibers have a tendency to move in the direction of the small arrows as shown. FIG. 2B illustrates the positions of fibers 8 and 11 a fraction of a second later. As shown, fiber 8 has slid along wire 9 causing it to jam into the crevice created by the intersection of wires 9 and 12. On the other hand, the air currents do not tend to move fiber 11 into such a crevice since the air currents are generally normal to wire 12. Hence, fiber 11 can gradually work its way free as shown due to uneven drag forces on different parts of the fiber. Those portions of the fiber closer to the impact elements experience greater drag force, causing eventual loosening of the fiber from the wire. In addition, the wake of the impact elements helps lift the fibers off the wire.
Another difficulty with the use of wire screens is that fiber aggregates can lodge themselves in the mesh openings if the openings are too small. On the other hand, the aggregates will pass through the mesh openings if they are too large. The first situation is undesirable because the throughput capacity of the apparatus is diminished. The second situation is of course undesirable because the product will contain a large number of fiber aggregates instead of solely individual fibers.
On the other hand, the outlet of an apparatus of this invention, a section of which is illustrated in FIG. 3, to a large extent overcomes these difficulties. Shown is an impact element 1 which is driven by a rotating shaft 14 in the arcuate path indicated by arrow 2. The outlet of the apparatus is generally indicated by reference numeral 3. As shown, the outlet consists essentially of a series of spaced-apart parallel plates 5 having a rectangular cross-section as viewed from the ends 15. Each of the plates has a leading surface 16 which generally faces the approaching impact elements. The leading surfaces are preferably as smooth as possible to prevent fibers from clinging to the surfaces. The orifice or space between the plates is preferably a continuous slot. In operation, the individual fibers tend to align themselves parallel to the air currents between the impact elements and the internal surface and eventually find their way through the outlet by passing between the plates 5. The distance between the plates can vary greatly depending upon the degree of classification or throughput desired. If only individual fibers are acceptable, the spacing between the plates will tend to be tighter than if some small aggregates are also acceptable. A spacing of about 1/8 to about 3/16 has worked well for producing product consisting essentially of individual fibers. Fiber aggregates or clumps of fibers will be hurled against the leading faces or surfaces of the plates and, due to the degree of slant, will be deflected back into the apparatus rather than be carried by the air currents and pass between the plates. This deflecting action is repeated until the aggregate is broken down into individual fibers or smaller aggregates which do not have sufficient momentum and therefore follow the bending air currents into the slot. It will be appreciated that optimal results will depend on a variety of factors such as the speed of the impact elements, the width of the slot, the characteristics of the fibers and their aggregates, the clearance between the impact elements and the dividers, the degree of slant of the leading surface of the dividers relative to the direction of travel of the impact elements, the air flow rate through the apparatus, etc.
FIG. 4 is a side view of the apparatus shown in FIG. 3, more clearly illustrating the concept of this invention. In order to define what is meant by "inwardly slanted in the direction of travel of the impact elements" it is necessary to draw two vectors. Vector 21 represents the direction of travel of the passing impact element relative to point 22 of plate 5, which is closest to the passing impact element. Vector 23, which represents the inward slant of the leading surface of the divider, is a vector drawn from point 22 toward the inside of the apparatus along the line which represents the intersection of the plane of the leading surface 16 with a plane containing point 22 and defined by the arc of a point on the travelling impact element. Vectors 21 and 23, being in the same plane, intersect and form an acute angle as shown. Thus, for purposes herein, a leading surface is considered as being inwardly slanted in the direction of travel of the impact element when the angle is an acute angle. Also shown are the continuous slots 17 between the plates. The dashed line 25 (also shown in FIGS. 1, 5, 6, and 7) represents an imaginary extension of the internal surface extended through the outlet to provide a line of reference. The innermost portions of the dividers preferably do not extend inwardly (toward the inside of the apparatus) beyond the dashed line 25 in order to maintain the same clearance which exists between the impact elements and the internal surface of the chamber. The effectiveness of this arrangement for rejecting aggregates of fibers is illustrated by the dashed path of fiber aggregate 26, shown deflecting off of the leading surface 16. One can see that if the fiber aggregate strikes the ridges at a very shallow angle (nearly parallel to the direction of travel of the impact elements) the inward slant of the leading face of the divider need not be as great as if the fiber aggregate approaches at a steeper angle. It may be necessary to do some experimentation to determine the optimum angle for a particular system, but an inward slant of about 45° has been found to work very well. It is within the scope of this invention that the dividers be other than plates as shown, but plates are very convenient. For example, by cutting a series of bevelled continuous or semi-continuous slots out of a very thick solid surface, the same effect can essentially be achieved.
FIG. 5 is similar to FIG. 4, simply illustrating a slightly different profile for the innermost portion of the dividers. The leading surfaces of the innermost portion of the dividers of FIG. 5 are identical to those of FIG. 4, except the pathway taken by escaping fibers has been slightly altered by the orientation of the dividers extending downwardly further into the outlet. The dashed lines 27 show the position of the plates in FIG. 4 for comparison. The manner in which fiber aggregates are deflected is the same for the apparatus of FIGS. 4 and 5.
FIG. 6 illustrates another embodiment of this invention, wherein the dividers consist of a series of parallel rods 30. In this embodiment, the leading surface of the rod is inwardly slanted in the direction of travel of the impact elements as with the other embodiments, but because of the curved or rounded surface, the degree of inward slant changes from point to point. It is especially important with this embodiment that the rods be spaced closely enough to prevent fiber aggregates from striking the lower half of the rods and being deflected downwardly through the outlet. When using rods, there is an advantage in having the diameter of each rod sufficiently large enough to prevent a fiber from wrapping itself halfway or more around the rod. Hence, if a large enough rod is used, stapling of the fibers can be prevented.
FIG. 7 illustrates yet another embodiment of this invention having a slightly modified divider profile as shown.
It will be appreciated that the foregoing Drawing and detailed discussion is for purposes of illustration only and is not to be construed as limiting the scope of the invention, which is defined by the following claims.
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The throughput of an apparatus for processing fibrous materials is increased by a fiber outlet portion consisting essentially of a plurality of dividers oriented in a direction perpendicular to the direction of travel of the impact elements (such as hammers and rotor blades), said dividers having a leading surface which is inwardly slanted in the direction of travel of the impact elements and dividers being separated by continuous or semi-continuous slots.
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FIELD OF THE INVENTION
[0001] The disclosed invention is a device detection and service discovery system and method for a mobile ad hoc communications network. The system and method employs a centralized distribution model for sending update messages to the network nodes in a mobile ad hoc communications network, each update message based upon local application directory information that describes the network node.
BACKGROUND OF THE INVENTION
[0002] Short-range wireless systems have a range of less than one hundred meters, but may connect to the Internet to provide communication over longer distances. Short-range wireless systems include, but are not limited to, a wireless personal area network (PAN) and a wireless local area network (LAN). A wireless PAN uses low-cost, low-power wireless devices that have a typical range of ten meters. An example of a wireless PAN technology is the Bluetooth Standard. The Bluetooth Standard operates in the 2.4 GHz Industrial, Scientific, and Medical (ISM) band and provides a peak air-link speed of one Mbps and a power consumption low enough for use in personal, portable electronics such as a personal digital assistance or mobile phone. A description of the Bluetooth communication protocol and device operation principles is in Bluetooth Special Interest Group, Specification of the Bluetooth Standard, version 1.0B, volumes 1 and 2, December 1999. A wireless LAN is more costly than a wireless PAN, but has a longer range. An example of a wireless LAN technology is the IEEE 802.11 Wireless LAN Standard and the HIPERLAN Standard. The HIPERLAN Standard operates in the 5 GHz Unlicensed-National Information Infrastructure (U-NII) band and provides a peak air-link speed between ten and one hundred Mbps.
[0003] An ad hoc network is a short-range wireless system comprising an arbitrary collection of wireless devices that are physically close enough to exchange information. An ad hoc network is constructed quickly with wireless devices joining and leaving the network as they enter and leave the proximity of the remaining wireless devices. An ad hoc network also may include one or more access points, that is, stationary wireless devices operating as a stand-alone server or as gateway connections to other networks.
[0004] In the future, the Bluetooth Standard will likely support the interconnection of multiple piconets to form a multi-hop ad hoc network, or scatternet. In a scatternet, a connecting device forwards traffic between different piconets. The connecting device may serve as a master device in one piconet, but as a slave device or a master device in another piconet. Thus, the connecting devices join the piconets that comprise a scatternet by adapting the timing and hop sequence to the respective piconet and possibly changing the roles that they serve from a master device to a slave device.
[0005] A Bluetooth device includes, but is not limited to, a mobile telephone, personal or laptop computer, radio-frequency identification tag, and personal electronic device such as a personal digital assistant (PDA), pager, or portable-computing device. Each Bluetooth device includes application and operating system programs designed to find other Bluetooth devices as they enter and leave the communication range of the network. The requesting Bluetooth device in a client role and the responding Bluetooth device in a server role establish a link between the two devices. The requesting and responding Bluetooth device use the link and a service discovery protocol to discover the services offered by the other Bluetooth device and how to connect to those services.
[0006] Prior art systems follow similar patterns of behavior for service discovery protocols. A service description, created using a description language and an appropriate vocabulary, is advertised or made available for query matching. Some prior art systems advertise the service description by pushing the description to a directory and requiring the advertisers to discover the directory. Other prior art systems advertise the service description by making the descriptions available for peer-to-peer discovery. A client device that needs to discover the service description composes a query using a query language and a matching vocabulary and uses either a query protocol or a decentralized query-processing server to deliver the query.
[0007] Service discovery protocols in the prior art systems require sending and replying to inquiry messages. If no other device is present, the inquiry messages are sent in vain. To avoid excessive power consumption, the prior art systems typically require a human user to manually initiate device detection when another device of interest is present. For example, a human user manually initiates device detection when connecting a cellular telephone to a laptop computer to handle data communications or when connecting a wireless headset to a laptop computer to deliver digital audio. These prior art systems rely upon three assumptions. First, an application can be freely started because the presence of its services is guaranteed. Second, an application performs service discovery when it first needs a service. Third, the composition of the network does not change during the lifetime of the application.
[0008] Thus, there is a need for a device detection and service discovery protocol that will avoid excessive power consumption and allow an application resident in one device to automatically find a counterpart application or some other resource resident in any of the remaining devices within the ad hoc communications network. The protocol does not require a human user to manually initiate device detection to find the counterpart application or other resource. Furthermore, the protocol will accommodate a network environment in which the presence of a particular service is not guaranteed and in which the composition of the network is dynamic because devices frequently enter and leave the network. The disclosed invention addresses this need.
SUMMARY OF THE INVENTION
[0009] A system and method of performing device detection and service discovery in a mobile ad hoc communications network including at least one network node, each network node storing a local application directory. The system and method selects a directory server node from said at least one network node, the directory server node having a coverage area and storing a combined application directory. The directory server node sends an inquiry message to a listening node when the listening node enters the coverage area of the directory server node. The listening node sends a notification message to the directory server node, the notification message comprising the local application directory stored in the listening node. The directory server node stores an update to the combined application directory based on a comparison of the local application directory included with the notification message and the combined application directory. The directory server node sends an update message to each network node communicating with the mobile ad hoc communications network, the update message comprising an update portion of the combined application directory for updating the local application directories of each of the nodes within the mobile ad hoc communications network.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying figures best illustrate the details of the device detection and service discovery system and method for a mobile ad hoc communications network, both as to its structure and operation. Like reference numbers and designations in these figures refer to like elements.
[0011] [0011]FIG. 1 is a network diagram that illustrates the interaction of the devices that comprise a mobile ad hoc communications network.
[0012] [0012]FIG. 2A is a block diagram that illustrates the hardware and software components comprising server 110 shown in FIG. 1.
[0013] [0013]FIG. 2B is a block diagram that illustrates the hardware and software components comprising terminal 120 shown in FIG. 1.
[0014] [0014]FIG. 3A is a flow diagram of an embodiment of server 110 performing device detection and service discovery for a mobile ad hoc communications network.
[0015] [0015]FIG. 3B is a flow diagram of an embodiment of terminal 120 performing device detection and service discovery for a mobile ad hoc communications network.
[0016] [0016]FIG. 4A is an exemplary block diagram of the data flow before a terminal enters a mobile ad hoc communications network.
[0017] [0017]FIG. 4B shows the exemplary block diagram of FIG. 4A after the terminal enters the mobile ad hoc communications network.
DETAILED DESCRIPTION OF THE INVENTION
[0018] [0018]FIG. 1 is a network diagram that illustrates the interaction of the network nodes that comprise a mobile ad hoc communications network. In one embodiment, the mobile ad hoc communications network is a Bluetooth piconet that includes one master device and up to seven active slave devices. As shown in FIG. 1, piconet 100 includes server 110 and five instances of terminal 120 . Server 110 maintains the network clock and is the communication manager for each instance of terminal 120 . Server 110 typically initiates an exchange of data with an instance of terminal 120 . Two instances of terminal 120 typically communicate through the server 110 however, if two instances of terminal 120 communicate directly, one instance will assume the role of server, or master, and the other instance will assume the role of client, or slave.
[0019] Each device in the mobile ad hoc communications network will either assume the role of a terminal device or a server device. A terminal device is a consumer of services that a single user operates. A terminal device includes devices such as a mobile phone or PDA. A server is typically a stationary device and only produces services. A server device creates a hotspot around them for using their services. “Hotspot” refers to the radio coverage area provided by the server device for detecting devices and discovering services offered by the applications hosted in the server. If the server device is not stationary, one of the terminal devices in the network will assume the role of application directory server and perform device detection and service discovery functions for the remaining terminal devices in the network. The disclosed invention introduces two roles among such terminal devices, application directory servers and terminals, where application directory servers serve terminals in device detection and service discovery. If stationary servers with hotspots exist, servers typically act as application directory servers however, device detection and service discovery is possible without such a stationary server because one of the terminals will assume the application directory server duties.
[0020] The disclosed invention categorizes an application as a server-based application, terminal-to-terminal application, foreground application, background application, or generic application component. A server-based application requires a server to produce a service. A terminal-to-terminal application requires at least two terminal devices to implement a service without the presence of a server device. A foreground application is an application resident in a terminal device that a user accesses via the user interface of the terminal device. A background application is an application resident in a terminal device that may start without any intervention by the user A generic application component can be used either as a standalone application or as a component of another application.
[0021] An application may be further categorized as either active, passive, new, or rejected. An active application is a foreground or background application that is resident in (i.e., stored in memory) the terminal. A passive application is resident in the terminal, but has not yet been started. In another embodiment, the passive application is started, but is not actively looking for other instances of the same application. A new application is not yet resident in the terminal, but might be in the future. A rejected application is not resident in the terminal and has been marked by the user as an application that should never be resident in the terminal. In another embodiment, the rejected application was once resident in the terminal, but was subsequently deleted and marked as rejected. In yet another embodiment, the rejected application never resided in the terminal, but is of a type of application that the user has marked as rejected.
[0022] Service discovery in a mobile ad hoc communications network differentiates between a resident application and an unloaded application. A resident application is stored in the terminal memory and loaded as either a foreground application or a background application. An unloaded application is not yet stored or loaded in the terminal, but has been accepted by the user. Typically, when an application was previously used, but has been overwritten to reclaim space, the application is considered unloaded. Thus, starting an unloaded application may require first downloading the application.
[0023] Service discovery from the perspective of the terminal device requires categorizing the status of an application as either an active resident application, active unloaded application, passive resident application, passive unloaded application, rejected application, or new application. An active resident application is loaded in the terminal and looking for peers, servers, or clients. An active unloaded application is not loaded in the terminal, but is still looking for such counterpart applications that could be automatically downloaded if found interesting. A passive resident application is loaded in the terminal, but is not looking for counterpart applications. A passive unloaded application is not loaded in the terminal, but was once accepted by the user. A rejected application is an application that a user has requested to exclude from the terminal device. A new application is not loaded in the terminal device, but the user might have seen an application in an earlier server for instance.
[0024] [0024]FIG. 2A is a block diagram that illustrates the hardware and software components comprising server 110 shown in FIG. 1. Server 110 is a general-purpose wireless device. Bus 200 is a communication medium that connects keypad 201 , display 202 , central processing unit (CPU) 203 , and radio frequency (RF) adapter 204 to memory 210 . RF adapter 204 connects via a wireless link to terminal 120 and is the mechanism that facilitates network traffic between server 110 and terminal 120 .
[0025] CPU 203 performs the methods of the disclosed invention by executing the sequences of operational instructions that comprise each computer program resident in, or operative on, memory 210 . Memory 210 includes operating system software 211 , application programs 212 , and middleware software 220 . Operating system software 211 controls keypad 201 , display 202 , RF adapter 204 , and the management of memory 210 . Application programs 212 control the interactions between a user and server 110 . Middleware software 220 includes an application program interface (API) 221 that help an application program running on server 110 find and communicate with a counterpart application running on terminal 120 . To quickly locate each application, middleware software 220 also includes application directory 230 to track the role assumed by each application that is resides in each device in piconet 100 .
[0026] [0026]FIG. 2B is a block diagram that illustrates the hardware and software components comprising terminal 120 shown in FIG. 1. Terminal 120 is a general-purpose wireless device. Bus 250 is a communication medium that connects keypad 251 , display 252 , CPU 253 , and RF adapter 254 to memory 260 . RF adapter 254 connects via a wireless link to server 110 or another terminal 120 and is the mechanism that facilitates network traffic between server- 110 and terminal 120 .
[0027] CPU 253 performs the methods of the disclosed invention by executing the sequences of operational instructions that comprise each computer program resident in, or operative on, memory 260 . Memory 260 includes operating system software 261 , application programs 262 , and middleware software 270 . Operating system software 261 controls keypad 251 , display 252 , RF adapter 254 , and the management of memory 260 . Application programs 262 control the interactions between a user and terminal 120 . Middleware software 270 includes an API 271 that help an application program running on terminal 120 find and communicate with a counterpart application running on server 110 or another terminal 120 . To quickly locate each application, middleware software 270 also includes application directory 280 to track the role assumed by each application that is resident on each device in piconet 100 .
[0028] In one embodiment, the configuration of memory 210 and memory 260 is identical. In another embodiment, the configuration of memory 210 and memory 260 only includes the software necessary to perform the essential tasks of server 110 and terminal 120 , respectively. For example, if terminal 120 needs to receive a general inquiry access code, but does not need to send a general inquiry access code message, only the software that sends this message will reside in memory 260 .
[0029] An application executing on a terminal is constantly searching for a counterpart application, that is, another instance of the same application that can communicate with the application. Each instance of an application assumes a particular role. Communication between an application and a counterpart application is only meaningful if the roles are complementary. For example, an application that assumes the role, of “client” can communication with a counterpart application that assumes the role of “server”. Middleware software is a software layer with an API that negotiates the communication, between two applications to help an application find a counterpart application with the correct role. Thus, an application installed in a terminal and activated, will query the API for a continuous stream of new counterpart applications that are of interest.
[0030] A new application is installed by “installer” applications that use middleware for finding counterparts and installing the new application into the local storage of a terminal. The actual finding and selection of new applications takes place in the application level. Initially, the installer application will be a dedicated “browser-supplier” (i.e., client-server) application that accesses counterpart applications in servers, browses their available application databases, allows a user to pick the applications to install, and downloads and installs the new applications. Later, the corresponding functionality may be added to a wireless access protocol (WAP) and hypertext markup language (HTML) browsers.
[0031] Service discovery is viewed as a three step process. First, new potential applications are found and will be considered for installation. Second, active installed applications begin to search for counterpart application. Third, active installed applications begin searching for common resources such as printers (i.e., resource discovery). The disclosed invention relies upon the applications to perform resource discovery. Typically, a terminal application communicates with its counterpart application and use local (i.e., server) resources. If an application uses a private resource, the associated service discovery is implemented by the application in a standard (e.g. Bluetooth or Bluetooth/Java) way not supported by the terminal middleware software.
[0032] [0032]FIG. 3A is a flow diagram of an embodiment of the disclosed invention, wherein one network node assumes a role of a directory server, such as, server 110 performing device detection and service discovery for a mobile ad hoc communications network. The process begins when server 110 sends a general inquiry access code message to terminal 120 (step 300 ). Terminal 120 receives the message and sends an acknowledgment response message to server 110 (step 302 ). Server 110 accesses middleware software 220 to request a socket connection with terminal 120 (step 304 ). In response to establishing the socket connection, server 110 receives a message from terminal 120 that includes a local application directory listing all of the applications that are locally resident on terminal 110 (step 306 ). Server 110 compares the list of applications resident on terminal 120 to a combined application directory resident on server 110 . Server 110 updates the combined application directory by adding to the combined application directory each entry in the local application directory that does not appear in the combined application directory (step 308 ). Server 110 sends a portion of the updated combined application directory to each terminal 120 in piconet 100 (step 310 ). The portion may vary for each terminal 120 and includes each entry in the combined application directory that is a counterpart application to an application resident in terminal 120 . In another embodiment, server 110 sends the entire combined application directory to each terminal 120 in piconet 100 and relies upon terminal 120 to retain the pertinent entries. Instances of middleware software in terminal 120 and server 110 begin to schedule the newly found counterpart application pairs for execution (step 312 ). In one embodiment, the scheduled applications make use of any other Bluetooth profile and protocol. In another embodiment, an application that is an installer application may suggest to the user other applications that the user should download. Once server 110 downloads and starts a new application, counterpart matching repeats and the new application becomes a part of the middleware scheduling.
[0033] [0033]FIG. 3B is a flow diagram of an embodiment of the disclosed invention, wherein one network node assumes a role of a directory server, such as, terminal 120 performing device detection and service discovery for a mobile ad hoc communications network. The process begins when terminal 120 receives a general inquiry access code message from server 110 (step 320 ). Terminal 120 generates and sends an acknowledgment response message to server 110 (step 322 ). Terminal 120 sends a message to server 110 that includes a local application directory that includes all of the applications that are locally resident on terminal 110 (step 324 ). Server 110 compares the list of applications resident on terminal 120 to a combined application directory resident on server 110 . Server 110 updates the combined application directory by adding to the combined application directory each entry in the local application directory that does not appear in the combined application directory. Terminal 120 receives from server 110 a portion of the updated combined application directory (step 326 ). Server 110 customizes the portion for terminal 120 to include each entry in the combined application directory that is a counterpart application to an application resident in terminal 120 . In another embodiment, server 110 sends the entire combined application directory to terminal 120 and relies on terminal 120 to retain the pertinent entries. Instances of middleware software in terminal 120 and server 110 begin scheduling these newly found counterpart application pairs for execution (step 328 ).
[0034] [0034]FIGS. 4A and 4B are exemplary block diagrams showing the content of the application directory before terminal X and terminal Y enter a mobile ad hoc communications network served by server S. FIG. 4A shows the configuration of application directory 404 , application directory 415 , and application directory 425 before terminal X and terminal Y enter a communication network managed by server S, a master device. Application C 401 resides in server S memory 400 and accesses middleware software 403 via API 402 . Middleware software 403 registers application C 401 with application directory 404 by adding a table entry to indicate that application C resides in the local device (i.e., server S) and assumes the role of server. Application A 411 and application B 412 reside in terminal X memory 410 and access middleware software 414 via API 413 . Middleware software 414 registers application A 411 and application B 412 with application directory 415 by adding a table entry to indicate that application A resides in the local device (i.e., terminal X) and assumes the role of client and that application B resides in the local device (i.e., terminal X) and assumes the role of peer. Application B 421 and application C 422 reside in terminal Y memory 420 and access middleware software 424 via API 423 . Middleware software 424 registers application B 421 and application C 422 with application directory 425 by adding a table entry to indicate that application B resides in the local device (i.e., terminal Y) and assumes the role of peer and that application C resides in the local device (i.e., terminal Y) and assumes the role of client.
[0035] [0035]FIG. 4B shows the configuration of application directory 404 , application directory 415 , and application directory 425 after terminal X and terminal Y enter the communication network managed by server S, a master device. Server S assumes the role of an application directory server (ADS) and mediates the registration of the applications residing in each device in piconet 100 . Server S adds a table entry to application directory 404 for each application residing in a device on piconet 100 . Thus, server S adds an entry for application A residing in terminal X in a client role, application B residing in terminal X in a peer role, application B residing in terminal Y in a peer role, and application C residing in terminal Y in a client role. Server S also updates application directory 415 in terminal X and application directory 425 in terminal Y with application registrations that may be interesting to those terminal devices. As shown in FIG. 4B, terminal X and terminal Y both host application B in a peer role. Since, a peer-to-peer communication session between application B on terminal X and application B on terminal Y is likely, server S adds an entry to application directory 415 for application B residing in terminal Y in a peer role and an entry to application directory 425 for application B residing in terminal X in a peer role. Also, since a client-server communication session between application C on terminal Y and application C on server S is likely, server S adds an entry to application directory 425 for application C residing in server S in a server role. Finally, there is no counterpart in piconet 100 for application A on terminal X.
[0036] As shown in FIGS. 4A and 4B, the disclosed data items for each entry in the middleware software application directory server include a device identifier (e.g., “local”, an address, or other unique identifier), an application identifier (e.g., application name or other unique identifier), and a role for the application (e.g., “client”, “server”, “peer”, etc.). In another embodiment, the data items can be expanded to include fields for the local applications (i.e., device=“local”) and fields for remote applications in other terminals or servers. The fields for the local applications include:
[0037] Name—An identifier for the application (e.g., supplier name and data to compare different versions and hardware variants);
[0038] My_role—The role that the application takes in the local device;
[0039] Partner_role—The role that the application assumes from interesting counterparts (e.g., peer, client, and server are the most common roles);
[0040] Residency—Either RESIDENT (installed and currently in memory), UNLOADED (installed once, not currently in memory, but can be re-downloaded automatically), REJECTED (indicates to the new application installer that it should ignore the application), and NEW (the application is not installed or rejected);
[0041] State—Either RUNNING (has communications, is now working with its remote counterparts, but there may be either only one, or more, applications that can use the communications at a time), WAITING (in execution but does not have any communications), STARTABLE (active, if a matching peer with the right partner_role is found, the middleware software starts this application, downloading the software first if needed), COMPLETE (all counterpart applications are aware), and PASSIVE (user must do something to start application);
[0042] Type—Eitehr FOREGOUND (when the application terminates, the state will be PASSIVE), and BACKGROUND (if the application terminates, the state will: be STARTABLE);
[0043] Unload—Either AUTOMATIC (middleware may remove code when the application has terminated), or UNINSTALL (user must confirm removals);
[0044] Icon—Creates a visual image of the application for the user; and
[0045] Timeout—Sets a time limit that the middleware software uses to detect, for example, when the application is in an unproductive software loop.
[0046] The fields for the remote applications include:
[0047] Device—An address for establishing communications with the terminal or server storing the application instance;
[0048] Name—An identifier for the application; and
[0049] My_role—The role that the application takes in the remote device.
[0050] The client-server roles of the applications are independent of the roles of the devices as a terminal device and an application directory server. Typically, the device acting as an application directory server hosts applications acting in a server role and the terminal devices act in the client role for the same application. In another embodiment, two terminal devices each send a general inquiry access code message and listen for a reply. The terminal device that first receives a response first will assume the server role and proceed according to the procedure in FIG. 3A. Another terminal device that receives the inquiry message will assume the terminal role, and proceed according to FIG. 3B. Thus the, disclosed invention supports terminal-to-terminal scenarios (e.g., one of identical handheld devices automatically becoming an ADS) and does not require predetermined application directory servers.
[0051] Although the disclosed embodiments describe a fully functioning device detection and service discovery system and method for a mobile ad hoc communications network, the reader should understand that other equivalent embodiments exist. Since numerous modifications and variations will occur to those who review this disclosure, the device detection and service discovery system and method for a mobile ad hoc communications network is not limited to the exact construction and operation illustrated and disclosed. Accordingly, this disclosure intends all suitable modifications and equivalents to fall within the scope of the claims.
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A system and method of performing device detection and service discovery in a mobile ad hoc communications network, each network node storing a local application directory. One of the network nodes is selected to be a directory server node that stores a combined application directory. The directory server node sends an inquiry message to a listening node when the listening node enters the coverage area of the directory server node. The listening node sends a notification message to the directory server node that includes the local application directory stored in the listening node. The directory server node compares the received local application directory to the combined application directory and updates the combined application directory accordingly. The directory server node sends an update message to each network node by sending an update portion of the combined application directory. Each network node updates the local application directories accordingly.
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FIELD OF THE INVENTION
[0001] This invention relates to the field of signal processing, and in particular to a digitally controlled oscillator (DCO) for generating clock signals.
BACKGROUND OF THE INVENTION
[0002] In processing mixed analog and digital signals, one of the most important factors for good performance of an analog circuit, as part of a mixed signal circuit, is the amount of jitter in bandwidth of interest of the analog circuit. Jitter manifests itself as unwanted variation in the interval between clock pulses. This factor is extremely important in situations where the analog part of the circuitry uses a digital clock for its sampling or over-sampling clock (e.g. analog-to-digital converters (ADCs) and digital-to-analog converters (DACs).
[0003] In the digital era, where the trend is to use as many digital circuits as possible, digital clock synthesizers (i.e. DCOs) are used more and more to create sampling clocks for different analog circuits. DCO generated clocks have uniformly distributed jitter ranging from DC up to half of the clock carrier frequency. Since this bandwidth always includes the range of interest of most mixed signal circuits, there is a need for a circuit that can shift digital jitter into high frequency area, outside the range of interest, where the performance of the circuits is not affected.
[0004] In previous implementations, e.g. ADC and DAC converters, a clean clock from a crystal oscillator was used as a sampling clock. When a network clock, or clock from a digital source, such as DCO, had to be used as sampling clock, the DCO output clock was first filtered with an analog phase locked loop (APLL) before being used.
[0005] U.S. Pat. No. 6,396,313 describes a jitter shaping circuit. This jitter shaper has a peak-to-peak jitter that increases with order with 2 master clock cycles per order.
SUMMARY OF THE INVENTION
[0006] The invention provides a digitally controlled oscillator (DCO) with the capability of shifting low frequency digital jitter, on its output clock, into higher frequency jitter. Embodiments of the invention permit the reduction of the sampling clock jitter, within the bandwidth of interest for a mixed signal circuit, with fully digital circuit, which is smaller in size and consumes less power than an equivalent circuit with DCO followed by an APLL. In addition to size and power advantages, embodiments of this invention give better results of jitter suppression at the bandwidth of interest due to the fact that APLLs have jitter gain in low frequency area. The invention allows mixed signal circuits to perform better in removing other type of noise that needs to be removed from signals that are being processed.
[0007] Accordingly therefore the invention provides a digitally controlled oscillator (DCO) for generating an output clock, comprising an overflow counter for generating an output signal determined by a clock frequency signal; a frequency control adder responsive to a frequency control input value to determine the frequency of said output clock; a DCO accumulator for accumulating the output of said frequency control adder and generating an enable signal for said overflow counter, said DCO accumulator also outputting a remainder value with said enable signal; and a jitter shaping circuit for shifting low frequency digital jitter on the output clock into higher frequency jitter, said jitter shaping circuit comprising: a jitter shaping accumulator for accumulating an error in edge placement; a clock advancement circuit for advancing the output signal from the overflow counter whenever there is an overflow of the jitter shaping accumulator; and an error resolution circuit for normally setting the input to said jitter shaping accumulator as the remainder value or the difference between said remainder value and said frequency value when an adjustment in edge placement of said output signal occurs.
[0008] The invention can be used in mixed signal circuits to generate clocks that are necessary for analog part of the circuit, as well as in digital circuits to generate clock that can be used by external analog or mixed signal devices.
[0009] Functionality of the DCO can be simplified by presenting it as an accumulator that can have fixed numerical value on its input, run by a high frequency master clock. Depending on the input value, the accumulator will overflow after certain number of master clock cycles. The overflow bit can be used as gating signal for the master clock in order to generate the output clock (logical AND function), which will on average have desired clock frequency.
[0010] The input value to the accumulator is proportional to the desired clock frequency. The phase difference between the output clock and the ideal clock is proportional to the accumulator value at the time of overflow, named remainder. When the remainder value is zero at the time of the overflow the output clock edge is phase aligned with the ideal clock edge. The maximum value of the remainder represents the biggest phase error in the output clock edge position. Each different value in the accumulator, at the point of the overflow, also represents amplitude of the output clock jitter. Since the accumulator can have any possible value at the overflow, the output clock jitter amplitude will have any value between zero and one master clock period. When the output clock frequency does not have common denominator with the master clock frequency, all jitter components will be randomly distributed with equal probability; therefore the output clock jitter will have uniform distribution.
[0011] The invention is based on the use of the DCO accumulator remainder to change the output clock position, such that additional clock edge repositioning will be performed for low frequency changes, therefore shifting low frequency jitter into high frequency jitter.
[0012] The DCO accumulator remainder value, representing error in the output clock edge placement, is additionally accumulated. Overflow value of the additional remainder accumulator is used to determine whether the edge repositioning is necessary or not. The overflow signal is also used as the feedback signal to the remainder accumulator, by changing the remainder accumulator input value when the overflow happens.
[0013] The invention is more efficient than the shaper described in U.S. Pat. No. 6,396,313 because maximum peak-to-peak jitter produced by is in one embodiment 2 master clock cycles, regardless of jitter shaping order (jittershaper produces maximally master clock cycle peak-to-peak of high frequency jitter on top of one master clock generally uniformly distributed frequency coming from the DCO). In case of the prior art jittershaper, peak-to-peak jitter increases with order with 2 master clock cycles per order. The jitter shaper of the present invention will just increase high frequency components when order is increased—it will never advance output clock for more than one master clock cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The invention will now be described in more detail, by way of example only, with references to the following drawings, in which:
[0015] FIG. 1 is a top-level block diagram of the DCO circuit according to the preferred embodiment; and
[0016] FIG. 2 is the block diagram of the Jitter Shaping module from FIG. 1 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] The noise reduction circuit comprises three main blocks, namely a digital controlled oscillator (DCO), a noise activity detector, and a spectral gain estimator.
DCO Overview
[0018] As shown in FIG. 1 , the DCO in accordance with an embodiment of the invention consists of a Frequency Control Adder 10 , the DCO Accumulator 11 , the Overflow Counter 12 and the Jitter Shaping Module 13 of first or higher orders. All static control signals for the DCO come through the Control Bus 14 , from external registers (not shown). In addition to the static control signals, there is an additional control bus 15 for the DCO center frequency control—feedback frequency control bus (‘fbk_freq_ctrl’). By using the feedback frequency control bus 15 , the DCO can be part of a digital phase locked loop (DPLL) that locks its output clock to an input reference clock. The feedback frequency control usually comes from a phase detector. Its value (2's complement binary number) is proportional to a phase difference between the DCO output clock and the input reference clock, such that the DCO center frequency is adjusted toward reducing the phase difference.
[0019] The static control signals are:
Freerun control signal 16 (‘freerun’), which determines whether the DCO output clock (‘clk_out’) 17 will be locked to an input reference signal (represented by ‘fbk_freq_ctrl’ control bus 15 ), or whether it will be free-running (based on local frequency oscillator). Center frequency number (CFN) 18 , which is a 2's complement binary number that represents the desired DCO center frequency, which is binary divided inside the Overflow Counter to get required output clock frequency. Output clock frequency control (‘clk_freq’) 19 , which is a control word that selects the desired output clock frequency. Jitter shaping enable signal (‘on/off’), which is used to turn the jitter shaping on or off.
[0024] The DCO center frequency, the highest DCO frequency that can be binary divided to a desired output clock frequency, can be chosen, based on the master clock frequency (‘mclk’), by programming appropriate CFN value into one of the control registers, using the following equation:
[0000]
f
DCO
=
CFN
+
fbk_freq
_ctrl
2
DCO_ACC
_WIDTH
*
f
mclk
[0000] where, f DCO represents the DCO center frequency, DCO_ACC_WIDTH represents width of the DCO Accumulator, and f mlck represents the master clock frequency.
[0025] In the DCO freerunning mode, when the ‘fbk_freq_ctrl’ value is zeroed, the DCO center frequency is proportional to the master clock frequency.
[0026] The feedback frequency control word (‘fbk_freq_ctrl’) is being added to the DCO Center Frequency Number (‘dco_cfn’) inside the Frequency Control Adder. The resulting bus ‘frequency’ is used as one of the Jitter Shaping Module inputs. The output of the adder (‘frequency’) is accumulated in the DCO Accumulator, consisting of the second adder and the register running on the master clock frequency (‘mclk’). The carry bit (‘dco_overflow’) of the accumulator is used as enable signal for the Overflow Counter 12 , which counts how many times the DCO has overflowed. The counter wraps around when it reaches the maximum (2 DCO — ACC — WIDTH −1). The overflow signal (‘dco_overflow’) and the remainder (‘remainder’) of the DCO Accumulator are also used as Jitter Shaping Module inputs. The ‘remainder’ consists of all bits of the Accumulator, excluding the most significant bit (‘dco_overflow’).
[0027] The Overflow Counter output (‘low_freq_ovf’), coming directly from one of the counter bits, represents an output clock with desired frequency, which is chosen by the output clock frequency control bus (‘clk_freq’). The ‘low_freq_ovf’ is also used as the Jitter Shaping Module input. The Overflow Counter is a basic binary counter, running on the master clock frequency (‘mclk’), with counting enable signal (‘dco_overflow’).
[0028] To perform jitter shaping on the Overflow Counter output (‘low_freq_ovf’), the Jitter Shaping module is used.
Jitter Shaping
[0029] For a given clock frequency and accumulator width, the DCO output clock frequency can only have discrete values. Therefore, the desired output clock frequency has limited accuracy. The remaining value in the DCO Accumulator at a carry (‘remainder’) represents the exact phase error of the carry pulse (‘dco_overflow’) with respect to an ideal signal.
[0030] The error is maximally 1/f mclk [sec] and it represents the intrinsic jitter of the DCO. Increasing the master clock frequency (‘fmclk’) reduces the intrinsic jitter. The ‘remainder’ can be used to correct the phase of the carry pulse, thereby allowing output jitter to be shaped. The remaining quantization error (jitter) can be removed over time by taking the rounding-error into account at the next rounding.
[0031] The Jitter Shaping circuit, shown in FIG. 2 , is used for clock generation. In the embodiment shown in FIG. 2 , the Jitter Shaping module 13 consists of the Error Resolution circuit 20 containing subtractor 31 and registers 32 , 33 , the Clock Advancement circuit 21 containing flip flops 23 , 24 , 25 and the Jitter Shaping Accumulator 22 containing adder 34 and register 35 .
[0032] The error in the edge placement is accumulated in the Jitter Shaping module 13 . Input to the Jitter Shaping Accumulator 22 is the error in the edge placement. As determined by the Error Resolution circuit, the error is represented by either the DCO ‘remainder’ or difference between the DCO ‘remainder’ and the DCO ‘frequency’.
[0033] Jitter shaping is carried out by advancing the output signal from the DCO Overflow counter whenever there is an overflow of the Jitter Shaping Accumulator 22 . The DCO Overflow Counter output signal ‘low_freq_ovf’ is actually a bit in the counter that has the desired output clock frequency.
[0034] Having in mind that advancement is not possible in a circuit without a feedback loop, the Overflow counter signal (‘low_freq_ovf’) is additionally delayed for two master clock cycles by flip flops 23 , 24 . The most delayed signal (‘low_freq_ovf_del3’) is used when no advancement is necessary, and the signal that is delayed for one master clock cycle less (‘low_freq_ovf_del2’) is used when advancement needs to happen. This is achieved by passing the third flip flop 25 with the aid of multiplexer 26
[0035] The jitter shaping process can be interpreted such that an advancement operation is required whenever the total (accumulated) difference between the output clock edge, when jitter shaping is not used, and an ideal edge position of that particular frequency clock reaches one master clock cycle.
[0036] The same Jitter Shaping Accumulator ‘js_overflow’ signal is used to select the error that is accumulated. Basically, when there is no adjustment (the Jitter Shaping Accumulator ‘js_overflow’ signal is low) the error representing the difference between the output clock edge and the ideal clock edge is equal to the DCO ‘remainder’. The DCO ‘remainder’ is the DCO phase value at the time of the DCO overflow.
[0037] When the adjustment happens, the edge placement error is equal to the difference between the DCO ‘remainder’ value and the DCO ‘frequency’ value. The DCO ‘frequency’ is the value that is accumulated inside the DCO on every master clock cycle, so it represents one master clock cycle, while the DCO ‘remainder’ is a fraction of the master clock cycle, and is always less than or equal to the DCO ’frequency’. Therefore, when the adjustment happens, the error is always negative number or zero.
[0038] Since the error is equal to the ‘remainder’ when there is no advancement, and the ‘frequency’ represents one master clock cycle, the error during advancement (when the Jitter Shaping Accumulator ‘js_overflow’ signal is high) must be represented as the difference between the two, because the advancement size is one master clock cycle. The Jitter Shaping Accumulator ‘js_overflow’ signal can also be seen as the feedback signal of the resulting advancement to the jitter shaping process, represented by the accumulator.
[0039] When jitter shaping is turned off, the Jitter Shaping circuit simply delays the DCO Overflow Counter signal for a couple of clock cycles. This delay comes as result of already mentioned delaying of the DCO Overflow Counter signal in order to make advancing possible.
[0040] The jittershaper according to the invention is more efficient since it is self contained using feedback information in the way that different value of phase error is being accumulated in the jittershaping accumulator depending on status of overflow of the accumulator (error is being either the DCO remainder or the DCO remainder minus DCO frequency). The DCO frequency value represents one master clock cycle phase in the output clock, while the DCO remainder represents fraction of the master clock period in the output clock phase, based on the ideal clock with the same frequency.
[0041] When jittershaping happens (output clock edge advancement), the accumulation error is being changed to compensate for that one master clock in order to keep output frequency with no additional jitter being added. Every unnecessary additional jitter degrades output clock.
[0042] The DCO in accordance with the invention can be part of a DPLL. This allows the DCO to suppress also components of jitter coming from the reference line to the DPLL.
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A digitally controlled oscillator (DCO) generating an output clock includes a jitter shaping module for shifting low frequency digital jitter on the output clock into higher frequency jitter.
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CROSS REFERENCE TO RELATED ART
This application claims the benefit of Korean Patent Application No. 10-2003-0015495, filed on Mar. 12, 2003, which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
The present invention relates generally to the field of communications, and more particularly to call error prevention using a communication unit.
BACKGROUND OF THE INVENTION
As mobile communication units become smaller and lighter, users find it increasingly difficult to input correctly telephone numbers via the ever decreasing in size mobile communication unit keypad. Furthermore, public telephone systems are programmed to automatically recognize specific telephone service codes such as “411” (telephone information), “611” (telephone repair), or the like in the United States, as well as general emergency call numbers such as “911” in the United States or “119” in South Korea, respectively, during telephone input.
As a result, if a user in South Korea were to attempt, for example, to make a telephone call to 011-9876-5432 via a mobile communication unit, by erroneously dialing 119-876-5432, i.e. failing to dial the first “0” digit, the mobile communication unit would automatically ignore the rest of the input digits after “119” and place an unsolicited call to the “119” general emergency call center.
A similar result would occur in the United States, if a user were to dial, for example, by mistake 911-609-2345 instead of 1-911-609-2345. In this case, since the input “911” is not a valid area code, but is a valid general emergency call number, the public telephone system automatically places an unwarranted call to the nearest general emergency call center. If the first three digits after a missed “1” in the United States are not recognized as either a valid area code or a valid emergency call number by the public telephone system, the system is programmed to generate an appropriate input error warning to the user.
No method or system for preventing call errors of this type is known in the prior art.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, a call error prevention method comprises the steps of inputting a call number, checking whether the input number is a recognizable call service code, determining whether the input number contains the same number of digits as a recognized call service code, and generating an input error warning if the input number does not contain the same number of digits as the recognized call service code.
In accordance with another aspect of the present invention, a call error prevention method comprises the steps of inputting a call number, checking whether the input number is a recognizable call service code, determining whether the input number contains the same number of digits as a recognized call service code, generating an input error warning if the input number does not contain the same number of digits as the recognized call service code, and checking whether a call is to be placed using the recognized call service code.
In accordance with yet another aspect of the present invention, a call error prevention method comprises the steps of inputting a call number, checking whether the input number is a recognizable emergency call number, determining whether the input number contains the same number of digits as a recognized emergency call number, generating an input error warning if the input number does not contain the same number of digits as the recognized emergency call number, and checking whether a call is to be placed using the recognized emergency call number.
In accordance with still another aspect of the present invention, a communication unit is adapted to check an input call number against a store of recognizable call service codes, determine whether the input number contains the same number of digits as a recognized call service code, and generate an input error warning if there is a mismatch in the number of digits between the input number and the recognized call service code.
In accordance with a different aspect of the present invention, a communication unit is adapted to check an input call number against a store of recognizable call service codes, determine whether the input number contains the same number of digits as a recognized call service code, generate an input error warning if there is a mismatch in the number of digits between the input number and the recognized call service code, and check whether a call is to be placed using the recognized call service code.
In accordance with a still different aspect of the present invention, a communication unit is adapted to check an input call number against a store of recognizable emergency call numbers, determine whether the input number contains the same number of digits as a recognized emergency call number, generate an input error warning if there is a mismatch in the number of digits between the input number and the recognized emergency call number, and check whether a call is to be placed using the recognized emergency call number.
These and other aspects of the present invention will become apparent from a review of the accompanying drawings and the following detailed description of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is generally shown by way of reference to the accompanying drawings as follows.
FIG. 1 schematically illustrates a mobile communication unit for use in accordance with the present invention.
FIG. 2 is a flowchart of a call error prevention method adapted for use in the mobile communication unit of FIG. 1 in accordance with one embodiment of the present invention.
FIG. 3 is a flowchart of a call error prevention method adapted for use in the mobile communication unit of FIG. 1 in accordance with another embodiment of the present invention.
FIG. 4 is a flowchart of a call error prevention method adapted for use in the mobile communication unit of FIG. 1 in accordance with yet another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Some embodiments of the present invention will be described in detail with reference to the related drawings of FIGS. 1-4 . Additional embodiments, features and/or advantages of the invention will become apparent from the ensuing description or may be learned by practicing the invention.
In the figures, the drawings are not to scale with like numerals referring to like features throughout both the drawings and the description.
The following description includes the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention.
FIG. 1 schematically illustrates a mobile communication unit (MCU) 10 comprising a radio frequency (RF) transceiver 12 adapted to operate in a full duplex mode via an antenna 14 , a voice processing module (VPM) 16 which receives input from a microphone 18 and generates output via a speaker 20 , and a controller 22 which manages the entire operation of MCU 10 . Controller 22 receives input from a keypad 24 and generates output via a display 26 . Controller 22 is operatively coupled between RF transceiver 12 , VPM 16 and a memory module 28 that stores programming needed for operation of MCU 10 as well as user data.
FIG. 2 is a flowchart of a call error prevention method adapted for use in MCU 10 of FIG. 1 in accordance with a preferred embodiment of the present invention. The call error prevention method of the present invention may be generally implemented using the following functional steps:
I. The user gets ready to place a telephone call by way of MCU 10 , “start” step 30 . II. The user inputs a telephone number via keypad 24 ( FIG. 1 ) and presses the “SEND” button (not shown) on keypad 24 , step 32 . A person skilled in the art would instantly recognize that the “call send” functionality of MCU 10 may be implemented in a variety of ways depending on the particular MCU architecture with the inclusion of a “SEND” button being just one of many such implementations. The input telephone number is stored in memory module 28 ( FIG. 1 ) and displayed for the user via display 26 ( FIG. 1 ) by controller 22 ( FIG. 1 ). III. Controller 22 checks with memory module 28 whether the input telephone number is a recognizable specific telephone service code, step 34 . Such a code may be, for example, “411”, “611”, or the like. If controller 22 determines that the input telephone number is not a recognizable specific telephone service code, controller 22 is adapted to connect the call via RF transceiver 12 ( FIG. 1 ) and antenna 14 ( FIG. 1 ), step 40 . IV. If controller 22 determines that the input telephone number is a recognizable specific telephone service code, controller 22 is adapted to check with memory module 28 whether the input telephone number contains the same number of digits as the recognized specific telephone service code, step 36 . If controller 22 determines that there is no mismatch in the number of digits, controller 22 is adapted to connect the call via RF transceiver 12 and antenna 14 , step 40 . V. If controller 22 determines that there is a mismatch in the number of digits, controller 22 instructs VPM 16 ( FIG. 1 ) and/or display 26 ( FIG. 1 ) to generate an appropriate user input error warning, step 38 . For example, VPM 16 may produce an audible warning to the user by way of speaker 20 ( FIG. 1 ), and/or a visible user warning may be shown on display 26 ( FIG. 1 ). Other types of warning may be generated for the user as long as such other warnings do not depart from the intended purpose of the present invention. To correct the call error, the user may re-input the telephone number, as generally shown in FIG. 2 .
FIG. 3 is a flowchart of a call error prevention method adapted for use in MCU 10 of FIG. 1 in accordance with another preferred embodiment of the present invention. The call error prevention method of the present invention may be generally implemented using the following functional steps:
I. The user gets ready to place a telephone call by way of MCU 10 , “start” step 42 . II. The user inputs a telephone number via keypad 24 ( FIG. 1 ) and presses the “SEND” button (not shown) on keypad 24 , step 44 . A person skilled in the art would instantly recognize that the “call send” functionality of MCU 10 may be implemented in a variety of ways depending on the particular MCU architecture with the inclusion of a “SEND” button being just one of many such implementations. The input telephone number is stored in memory module 28 ( FIG. 1 ) and displayed for the user via display 26 ( FIG. 1 ) by controller 22 ( FIG. 1 ). III. Controller 22 checks with memory module 28 whether the input telephone number is a recognizable specific telephone service code, step 46 . Such a code may be, for example, “411”, “611”, or the like. If controller 22 determines that the input telephone number is not a recognizable specific telephone service code, controller 22 is adapted to connect the call via RF transceiver 12 ( FIG. 1 ) and antenna 14 ( FIG. 1 ), step 54 . IV. If controller 22 determines that the input telephone number is a recognizable specific telephone service code, controller 22 is adapted to check with memory module 28 whether the input telephone number contains the same number of digits as the recognized specific telephone service code, step 48 . If controller 22 determines that there is no mismatch in the number of digits, controller 22 is adapted to connect the call via RF transceiver 12 and antenna 14 , step 54 . V. If controller 22 determines that there is a mismatch in the number of digits, controller 22 instructs VPM 16 ( FIG. 1 ) and/or display 26 ( FIG. 1 ) to generate an appropriate user input error warning, step 50 . For example, VPM 16 may produce an audible warning to the user by way of speaker 20 ( FIG. 1 ), and/or a visible user warning may be shown on display 26 ( FIG. 1 ). Other types of warning may be generated for the user as long as such other warnings do not depart from the intended purpose of the present invention. VI. Thereafter, or in conjunction with the previous step, controller 22 checks with the user via display 26 and/or VPM 16 and speaker 20 whether the user would like to call the recognized specific telephone service code, step 52 . If the user responds in the affirmative, e.g. via keypad 24 or microphone 18 , controller 22 connects the call via RF transceiver 12 and antenna 14 , step 54 . If the user responds in the negative via keypad 24 or microphone 18 , controller 22 directs the user via display 26 and/or VPM 16 and speaker 20 to start from the beginning, i.e. to re-input the correct telephone number, as generally illustrated in FIG. 3 .
FIG. 4 is a flowchart of a call error prevention method adapted for use in MCU 10 of FIG. 1 in accordance with yet another preferred embodiment of the present invention. The call error prevention method of the present invention may be generally implemented using the following functional steps:
I. The user gets ready to place a telephone call by way of MCU 10 , “start” step 56 . II. The user inputs a telephone number via keypad 24 ( FIG. 1 ) and presses the “SEND” button (not shown) on keypad 24 , step 58 . A person skilled in the art would instantly recognize that the “call send” functionality of MCU 10 may be implemented in a variety of ways depending on the particular MCU architecture with the inclusion of a “SEND” button being just one of many such implementations. The input telephone number is stored in memory module 28 ( FIG. 1 ) and displayed for the user via display 26 ( FIG. 1 ) by controller 22 ( FIG. 1 ). III. Controller 22 checks with memory module 28 whether the input telephone number is a recognizable emergency call number, step 60 . Memory module 28 contains pre-stored emergency call numbers which may be general emergency numbers such as “911” or “119” in the United States or South Korea, respectively, or the emergency telephone number to a local police or sheriff's station, the telephone number to a local poison control center, the telephone number to the nearest fire department station, or the like. If controller 22 determines that the input telephone number is not a recognizable emergency call number, controller 22 is adapted to connect the call via RF transceiver 12 ( FIG. 1 ) and antenna 14 ( FIG. 1 ), step 68 . IV. If controller 22 determines that the input telephone number is a recognizable emergency call number, controller 22 is adapted to check with memory module 28 whether the input telephone number contains the same number of digits as the recognized emergency call number, step 62 . If controller 22 determines that there is no mismatch in the number of digits, controller 22 is adapted to connect the call via RF transceiver 12 and antenna 14 , step 68 . V. If controller 22 determines that there is a mismatch in the number of digits, controller 22 instructs VPM 16 ( FIG. 1 ) and/or display 26 ( FIG. 1 ) to generate an appropriate user input error warning, step 64 . For example, VPM 16 may produce an audible warning to the user by way of speaker 20 ( FIG. 1 ), and/or a visible user warning may be shown on display 26 ( FIG. 1 ). Other types of warning may be generated for the user as long as such other warnings do not depart from the intended purpose of the present invention. VI. Thereafter, or in conjunction with the previous step, controller 22 checks with the user via display 26 and/or VPM 16 and speaker 20 whether the user would like to call the recognized emergency call number, step 66 . If the user responds in the affirmative, e.g. via keypad 24 or microphone 18 , controller 22 connects the call via RF transceiver 12 and antenna 14 , step 68 . If the user responds in the negative via keypad 24 or microphone 18 , controller 22 directs the user via display 26 and/or VPM 16 and speaker 20 to start from the beginning, i.e. to re-input the correct telephone number, as generally illustrated in FIG. 4 .
For example, if a user attempts to place a telephone call to 011-2345-6789 in South Korea using a wireless MCU which lacks the inventive functionality described hereinabove by erroneously dialing 112-3456-789 on the MCU keypad, an unwarranted emergency call would be automatically made to the (South Korean) “112” crime report center. As a result, the user may be fined by the authorities for frivolous use of the “112” crime report telephone number. If, however, a user were to erroneously dial 112-3456-789 instead of 011-2345-6789 in South Korea using a wireless MCU equipped with the inventive functionality described hereinabove, the MCU would automatically recognize the “112” crime report number and consult with the user regarding placement of the recognized emergency crime report telephone call, i.e. an emergency call error would be readily prevented.
A person skilled in the art would recognize that the above-described novel call error prevention functionality is not restricted to wireless MCUs, but may be easily implemented in landline communication units as well. A person skilled in the art would also recognize that the call error prevention functionality may be implemented in hardware and/or software form. Other components and/or configurations may be utilized in the above-described embodiments.
Moreover, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.
While the present invention has been described in detail with regards to several embodiments, it should be appreciated that various modifications and variations may be made in the present invention without departing from the scope or spirit of the invention. In this regard it is important to note that practicing the invention is not limited to the applications described hereinabove. Many other applications and/or alterations may be utilized provided that such other applications and/or alterations do not depart from the intended purpose of the present invention. Also, features illustrated or described as part of one embodiment can be used in another embodiment to provide yet another embodiment such that the features are not limited to the embodiments described above. Thus, it is intended that the present invention cover all such embodiments and variations as long as such embodiments and variations come within the scope of the appended claims and their equivalents.
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A call error prevention method comprises the steps of inputting a call number, checking whether the input number is a recognizable call service code, determining whether the input number contains the same number of digits as a recognized call service code, and generating an input error warning if the input number does not contain the same number of digits as the recognized call service code.
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BACKGROUND OF THE INVENTION
The present invention relates to a method for stabilizing an acidic aqueous hydrogen peroxide solution containing copper.
PRIOR ART AND PROBLEMS THEREOF
It is known that an acidic aqueous hydrogen peroxide solution has a high solubilizing ability as a chemical agent for copper and copper alloy materials. And such hydrogen peroxide solution is used widely for pickling, etching and chemical polishing of copper and copper alloy. However, hydrogen peroxide is a compound easy to decompose, and particularly in the presence of copper ion, it decomposes catalytically. Therefore, in the case of using an acidic aqueous hydrogen peroxide solution for chemically dissolving copper and copper alloy, once the copper dissolves and copper ions are accumulated in the solution, the decomposition of the hydrogen peroxide is accelerated, resulting in that the effective utilizability of hydrogen peroxide is deteriorated markedly, which is uneconomical.
Heretofore, for remedying such drawbacks, the addition of various compounds, e.g. phenols and saturated aliphatic alcohols, has been tried, buy for particular purpose of use it is desired to develop a more effective and new stabilizing method. It is object of the present invention to provide a method of stabilizing an acidic aqueous hydrogen peroxide solution by the use of a new additive.
SUMMARY OF THE INVENTION
The present invention resides in a method for stabilizing an acidic aqueous hydrogen peroxide solution containing copper ions which decompose hydrogen peroxide catalytically, characterized by adding to the acidic aqueous hydrogen peroxide solution an amino acid having an aromatic nucleus represented by the following formula: ##STR2## wherein Ar represents an aromatic group.
DETAILED DESCRIPTION OF THE INVENTION
An acidic aqueous hydrogen peroxide solution used for chemically dissolving copper (including copper alloy) usually contains 10 to 150 g/l of hydrogen peroxide and 10 to 200 g/l of an acid. As the acid, sulfuric acid is usually employed, but mineral acids such as nitric acid and phosphoric acid are also useful.
According to the present invention, by the addition of an amino acid having a specific structure, it is intended to prevent hydrogen peroxide from being decomposed by copper ions accumulated in such acidic aqwueous hydrogen peroxide.
The amino acid to be added is of the foregoing general formula, in which the aromatic group of Ar may be a carbon aromatic group or a heterocyclic aromatic group. Preferred examples are phenyl, substituted phenyls such as hydroxyphenyl and alkylphenyl, and indole.
Usually, the additive used in the invention is added 0.01 g/l or more to the acidic aqueous hydrogen peroxide solution. The upper limit is not specially limited, but usually an amount of 50 g/l or less is sufficient. In general, the additive is used in an amount of 0.1 to 10 g/l.
According to the method of the present invention described above, the decomposition of hydrogen peroxide can be suppressed effectively even in the case where copper dissolves and copper ions are accumulated, whereby it is made possible to render the use of an acidic aqueous hydrogen peroxide solution more economical as a chemical copper dissolving agent.
The following working examples and comparative example are given to illustrate the effect of the present invention.
EXAMPLE 1
An amino acid having an aromatic nucleus was added into an aqueous solution held at 50° C. and containing 100 g/l of H 2 O 2 , 150 g/l of H 2 SO 4 and 159 g/l of CuSO 4 -5H 2 O, and the amount of hydrogen peroxide decomposed was determined, the results of which are as shown in Table 1 below.
TABLE 1______________________________________ Amount of Hydrogen Amount Peroxide DecomposedAdditive (g/l) (g-H.sub.2 O.sub.2 /l · min)______________________________________Tyrosine 10 0.11 1 0.18 0.1 0.32Phenylalanine 10 0.27 1 0.51Tryptophan 1 0.66______________________________________
COMPARTIE EXAMPLE 1
The substances shown in Table 2 below were added into the same aqueous solution as in Example 1 and the amount of hydrogen peroxide decomposed were determined, the results of which are as shown in the same table.
TABLE 2______________________________________ Amount of Hydrogen Amount Peroxide DecomposedAdditive (g/l) (g-H.sub.2 O.sub.2 /l · min)______________________________________β-Alanine 10 2.3 1 3.0Serine 10 5.5Cysteine 10 4.1Aspartic acid 10 4.9Lysine 10 3.3Glutamine 10 3.0Histidine 10 4.5o-Aminobenzoic 10 2.0acidnot added 4.7______________________________________
From the above tables it is seen that the additives used in the present invention exhibit a remarkably excellent stabilizing effect as compared with other amino acids or analogs thereto.
EXAMPLE 2
The amount of hydrogen peroxide decomposed at 30° C. in an aqueous solution containing 70 g/l of H 2 O 2 , 30 g/l of HNO 3 , 159 g/l of CuSO 4 -5H 2 O and 1 g/l of tyrosine was 0.22 g/l.min, while the amount of hydrogen peroxide decomposed under the same conditions and without the addition of tyrosine was 6.7 g/l.min. Thus, the amount of hydrogen peroxide decomposed in the presence of tyrosine was only abut 1/30 of that in the absence of tyrosine.
EXAMPLE 3
The amount of hydrogen peroxide decomposed at 60° C. in an aqueous solution containing 100 g/l of H 2 O 2 , 50 g/l of H 3 PO 4 , 159 g/l of CuSO 4 -5H 2 O and 10 g/ of phenylalanine was 0.25 g/l.min, while the amount of hydrogen peroxide decomposed under the same conditions and without the addition of phenylalanine was 5.8 g/l.min. Thus, the amount of hydrogen peroxide decomposed in the presence of phenylalanine was only about 1/23 of that in the absence of phenylalanine.
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An acidic aqueous hydrogen peroxide solution containing copper can be stabilized by adding an amino acid having the formula ##STR1## wherein Ar is an aromatic group.
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This application is a division of U.S. application Ser. No. 608,348 filed May 8, 1984, now U.S. Pat. No. 4,575,619.
BACKGROUND OF THE INVENTION
The present invention relates to electrical heating units, and to methods of manufacturing such heating units. In particular, the present invention relates to a combination thermal insulating block and one or more electrical heating elements, and to methods for manufacturing such units.
It is necessary to use some form of thermal insulating material to confine heat, particularly at elevated temperatures. In recent years, thermally insulating panels have been molded which contain lightweight ceramic fibers. Such panels are highly porous, and provide good thermal insulation at relatively low cost. U.S. Pat. No. 3,500,444 to W. J. Hesse et al describes such a panel and a filter molding process for producing such panels. In addition, the Hesse patent discloses electrical heating elements mounted on or adjacent to one of the surfaces of such a panel for use in a domestic or commercial electric range.
A helical electrical heating element partially disposed upon the surface of a panel of molded inorganic refractory fibrous material and partially embedded in the panel has not proven satisfactory for many applications, such as the walls or roof of a high temperature furnace. A helical wire heating element requires support along its length to prevent sagging, particularly at elevated temperatures. Further, the expansion and contraction rates of the heating element and the molded thermal insulating block differ, tending to cause the heating coil to break free from the block of thermal insulating material. The thermal insulating material itself has little structural strength. Accordingly, there have been extensive efforts to develop superior constructions combining electrical heating elements with such molded thermal insulating blocks.
In addition to providing mechanical support for the heating element which is effective throughout the life of the heating element, it is desirable for the heating element to be positioned to provide maximum radiation and convection heat transfer to the work load and to provide the maximum thickness of thermal insulating material between the electrical heating element and the side of the insulating block opposite the heating element. These considerations must be balanced against cost and ease of production.
A combination heating element and thermal insulating panel suitable for use in a high temperature furnace is disclosed in U.S. Pat. No. 4,278,877 to E. R. Werych. This Werych patent discloses oval elongated thermal resistance coils embedded in the panel adjacent to one surface therof with the longitudinal axes of the coils parallel to the surface. In this manner the portion of each oval coil of the heating element remote from the surface is closer to the surface than it would be were the coil cylindrical, but this remote portion of the coil nonetheless will operate at a higher temperature than the portion of the coils adjacent to the surface.
The pending United States patent application of J. Boes and L. Saris, Ser. No. 477,725, now U.S. Pat. No. 4,617,450 entitled A VACUUM FORMED ELECTRICAL HEATING DEVICE AND METHOD OF PRODUCTION discloses a similar thermal panel in which the interior region of the oval heating coils is maintained substantially free of insulating material in order to reduce the temperature of the portion of the heating coil remote from the radiating surface of the panel. In one embodiment of the Boes and Saris application, the heating coils are positioned within the block of thermal insulating material and spaced from the radiating surface of the thermal insulating material, and slots or grooves are provided between the electrical heating coils and the heat radiating surface. This construction has the advantage of retaining the heating coils more securely in the block of thermal insulating material, but still permits the radiant energy and convection from the heating coils to impinge upon the work load. However, the interior portion of the oval heating elements do operate at a higher temperature than the portion of the heating elements adjacent to the radiating surface of the block, thus reducing the capacity and efficiency of the heating panel.
Resistance elements in the form of a rod of resistance material bent in a series of reverse spaced bends to form a flat element are common in the electric furnace art, and such elements have also been mounted on molded ceramic fiber insulating panels. U.S. Pat. No. 4,403,329 of E. R. Werych entitled SUPPORT SYSTEM FOR ELECTRICAL RESISTANCE ELEMENT discloses a pin for insertion in such ceramic fiber panels provided with a clip for engaging one of the bends of such a serpentine resistance element. U.S. Pat. No. 4,299,364 of P. J. Loniello entitled INSULATING MODULE INCLUDING A HEATER ELEMENT SUPPORT also discloses a rod molded in the insulating panel and extending therefrom, the rod being provided with keeper pins for retaining the electrical heating elements adjacent to the surface of the thermal insulating panel. While such mounting devices position the heating element to utilize the radiant and convection heat transfer produced by the heating element, and permit the thermal insulating block to provide substantially maximum thermal insulation, they are costly and require considerable hand assembly work in construction. In addition, the movable parts of such hangers and mounting structures tend to fail under severe use conditions.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a combination thermal insulating block and electrical heating element in which the heating element is mounted near the surface of the thermal insulating block, that is, without use of mounting brackets, and in which more of the heat produced by the heating element is transferred to the work load by radiation and convection than in such prior constructions. It is a further object of the present invention to provide a combination thermal insulating block and electrical heating element in which the electrical heating element is mounted near the surface of the block and in which the temperature difference between the hottest portion of the heating element and the coolest portion of the heating element is substantially lower than in such prior constructions.
It is also an object of the present invention to provide a method for producing thermally insulated heating panels with one or more electrical heating elements mounted near the surface of a thermal insulating block having the properties set forth above by a casting or molding process.
In accordance with the present invention a block of thermal insulating material containing inorganic fibrous material is provided with an elongated slot which extends into the block forming opposed walls on opposite sides of the axis of the slot. A heating element in the form of elongated serpentine wire with opposed bends on opposite sides of the axis of the wire is disposed in the slot with the bends on one side engaging one wall of the slot and the bends on the other side engaging the other wall of the slot. In a preferred construction, the walls of the slot are parallel, and the bends on one side are spaced from the bends on the other side by relatively straight portions of the electrical resistance wire, the straight portions being approximately parallel to each other and of equal length.
In another embodiment of the present invention, the portions of the resistance wire between the bends of opposite direction are not straight, but bow toward the heat radiating surface of the block.
In accordance with the present invention, the thermal insulating block is molded or cast with one or more slots or grooves, and an electrical heating element is molded in situ to each groove to form a thermally insulated heating panel. The electrical heating element may be formed in a number of different ways, and in a preferred process is formed of resistance wire by bending the wire at a plurality of locations along the length of the wire, each successive bend being in the opposite direction. The heating element is placed on a portion of the bottom of a frame which is raised above the adjacent portions of the bottom to form a plateau, one side of the heating element overlapping one side of the plateau and the opposite side of the heating element overlapping the opposite side of the plateau. Thereafter, a slurry containing inorganic fibers and a liquid is introduced into the frame, and the liquid removed to deposit the fibers on the bottom of the frame. The frame may contain a plurality of slots or grooves in the insulating block. A separate heating element is then placed on each plateau and a plurality of slots, each containing an electrical resistance element, is molded in situ in a single operation. Preferably, the bottom of the frame is porous, permitting the liquid to drain from the frame, thus facilitating deposit of the inorganic fibers on the bottom of the frame. The block thus formed is removed from the frame and dried.
Other and further objects and advantages of the present invention will be understood by reference to the following specification in conjunction with the annexed drawings, wherein like parts have been given like numbers.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a fragmentary isometric view of a combination electrical heating element and thermal insulating panel constructed according to the present invention;
FIG. 1a is a fragmentary isometric view of an alternative construction to the construction of FIG. 1;
FIG. 2 is a front elevational view of the panel of FIG. 1;
FIG. 3 is a plan view of one of the heating elements shown in FIGS. 1 and 2;
FIG. 4 is a diagrammatic view of processing equipment for producing the panel of FIGS. 1 through 3;
FIG. 5 is a fragmentary sectional view of a combination heating element and thermally insulated panel for use in a cylindrical furnace; and
FIG. 6 is a fragmentary sectional view, on a similar plane to FIG. 5, of a combination heating element and thermal insulating panel for use in a cylindrical furnace utilizing a modified serpentine heating element.
DESCRIPTION OF PREFERRED EMBODIMENTS
An electrical heating unit, or panel 10 embodying the present invention is illustrated in FIGS. 1 and 2. The panel has a molded block 12 of thermal insulating material. The block is preferably molded of inorganic ceramic fibers of the type disclosed in U.S. Pat. No. 3,500,444. In such a block, high refractory compositions, such as silica or quartz, magnesia, alumina-silica, and some other materials, produce inorganic fibers which exhibit resistance to deterioration at temperatures up to the order of 2,500° F. Blocks made of such compositions are relatively porous and provide excellent thermal insulation. Further, such blocks are readily molded into various shapes and are thus particularly suitable for forming the walls of a furnace, such as disclosed in U.S. Pat. No. 4,246,852 of Ewald R. Werych entitled INDUSTRIAL FURNACE WITH CERAMIC INSULATING MODULES.
The block 12 has two flat parallel surfaces 14 and 16, a face 18 extending between the surfaces 14 and 16, sides 20 and 22, and a back, not shown. The sides 20 and 22 can be provided with outwardly extending steps 24 and 26 which are adapted to mate with the recesses in other panels to form a closed furnace.
The block 12 is provided with a plurality of slots or grooves 28 which extend into the surface 16 of the block 12, the grooves 28 being elongated and having parallel walls 30 and 32, as illustrated in FIG. 1. In the modified construction of FIG. 1a, grooves 28a in block 12a have oblique opposed walls 30a and 32a. Adjacent grooves 28 are spaced by strips 34 and are parallel to each other. Each of the grooves 28 extends into the block 12 from the flat surface 16 essentially the same distance and forms a flat surface or land 36 which is engaged by a serpentine heating element 38.
The heating element 38 is an elongated electrical resistance wire 40 with two groups of bends 42 and 44. The bends 42 are separated from each other by a fixed distance along the axis of the wire 40, and the bends 44 are separated from each other by the same fixed distance. The bends 44 are each located essentially between bends 42 of the resistance wire, except for the last bend at each end of the wire. Each of the bends 42 and 44 have approximately the same radius of curvature, and each bend 42 is separated from the bends 44 by straight sections 46 of the resistance element. The connecting sections 46 are of equal length, thereby positioning the bends 42 on an axis which is parallel to an axis through the bends 44. Each of the bends 42 and 44 encompass an angle of 180° in the preferred construction illustrated in FIG. 3, and therefore, the straight sections 46 are parallel to each other. As a result of this construction, the heating element 38 approaches the maximum mass of heating element per unit of length for a given diameter wire 40 and for bends 42 and 44 of a given radius of curvature. The invention may be practiced however using bends 42 and 44 of less than 180°, and the sections between each bend 42 and 44 may be curved as will be hereinafter described. The wire 40 as illustrated in FIG. 3 is cylindrical in shape, but the wire may be flat, square, rectangular or the like.
Each of the heating elements 38 is disposed in one of the grooves 28 in abutment with the land 36 thereof. The straight sections 46 of the resistance elements 38 extend through the walls 30 and 32, and the bends 42 and 44 are embedded in the strips 34 between adjacent grooves 28. The heating element 28 is retained in assembly with the block 12 due to the engagement of the fibers of the block 12 with the bends 42 and 44 of the heating element 38.
As illustrated In FIG. 1, a portion of the connecting sections 46 of the heating elements 38 can be embedded in the strips 34 of the block 12. For best heat transfer, the bends 42 and 44 should merely abut the walls 30 and 32 of the grooves 28, but such a construction may not adequately attach the heating elements 38 to the block 12. The block 12 has little strength, and the heating element may exhibit considerable mass. Hence, it is generally necessary to at least partially embed the bends 42 and 44 into the strips 34. The depth of penetration of the bends 42 and 44 into the strips 34 changes upon heating of the resistance element 38. Expansion of the heating element 38 occurs along the entire axis of the element, but expansion of the connecting sections 46 force the bends 42 and 44 against the fibers of the block 12, thereby causing the bends to further penetrate the strips 34. The block 12 however has little shear strength, and the expansion of the resistance element produces a compressional force against the block 12 which significantly aids in retaining the heating element 38 in attachment to the block 12, particularly at elevated temperatures. Each of the bends 42 and 44 is embedded into one of the strips 34 by a distance generally no greater than one-fourth of the distance between the bends 42 and the bends 44, so that at least one-half of the resistance element 38 as measured between the bends 42 and 44 is disposed on the land 36.
Adjacent grooves 28 must be separated by sufficient distance so that the strip formed between the grooves provides adequate electrical insulation between adjacent electrical heating elements 38. The ceramic fibrous material of the block 12 is an electrical insulator, but the electrical insulating properties depend to some extent upon the specific materials used in the block and the associated environment and temperature in which it is used. Adjacent grooves 28 must be separated sufficiently to provide adequate electrical insulation for the application.
In one preferred construction, six grooves 28 are disposed in the flat surface of a block 12, each groove extending completely from the front surface 18 of the block to the back surface to a depth of 1/4 inch. Each groove has a width measured perpendicular to the walls 30 and 32 of 5/8 inch. The electrical resistance heating element 38 is constructed of 15 gauge Kanthal A-1 heating element wire with a cylindrical cross section and a resistance of 0.127 ohms per inch. The outer edges of the bends 42 are disposed on an axis displaced from the outer edges of the bends 44 by a distance of 7/8 inch, and hence approximately 3/16 inch of each bend 42 and 44 is embedded in the block 12.
The panel illustrated in FIGS. 1 and 2 is adapted to be incorporated with other panels to form a square or rectangular furnace, and the panels are adapted to be operated at temperatures up to approximately 2,500° F. FIG. 5 illustrates two interconnected panels 48A and 48B which form a fragment of a cylindrical furnace. Each of the panels 48A and 48B have a block 50 of thermal insulating material of the type described above with reference to the block 12. The block 50 has a cylindrical inner surface 52 and a cylindrical outer surface 54. The outer surface can be provided with a protective and abrasion resistant metal covering 56. It will be noted that the panel 48A and the panel 48B can be provided with mating stepped surfaces 58A and 58B to form a continuous cylinder as illustrated in FIG. 5.
Each block 50 is provided with a plurality of spaced slots 60 which extend normal to a plane tangent to the inner cylindrical surface and are otherwise identical to the slots 28 of the embodiment of FIGS. 1 and 2, the same reference numerals being used to identify identical portions of the slots 28 and 60. The slots 60 have lands 36 extending between walls 30 and 32, and the walls are separated by ribs 62. Electrical resistance heating elements 38, identical to the heating elements of the embodiment of FIGS. 1 and 2, are disposed upon the lands 36 and extend through the walls 30 and 32 into the ribs 62.
The embodiment of FIG. 6 is a modification of the embodiment of FIG. 5, and illustrates two panels 64A and 64B mounted together to form a cylindrical furnace which are identical to the panels 48A and 48B except the lands 36A of the slots 60A differ in that the lands 36A curve toward the heated surface.
In like manner, a modified resistance heating element 38A is disposed in each of the slots 60A in abutment with the land 36A thereof. The resistance heating element is identical to the heating element of FIG. 3, except the heating element of FIG. 6 has interconnecting sections 46A between the bends 42 and 44 provided with a curve extending from one bend 42 to the other bend 44, the curves being aligned to match the protrusion 66 of the land 36A.
The use of a transversely curved heating element, as illustrated in FIG. 6, has the advantage of being able to accommodate the linear expansion of the wire heating element without placing undue force on the material of the thermal insulating block of the panels 64A and 64B. Expansion of the wire of the resistance element 38A will be divided between compression of the material in the block of the panel 64A or 64B and curvature of the resistance element 38A itself.
FIG. 4 illustrates, somewhat diagrammatically, a possible apparatus for producing the panels of FIGS. 1 and 2. FIG. 4 illustrates a frame which is provided with a horizontal bottom 70. The bottom 70 supports a plurality of elongated upwardly rising plateaus 72. Each of the plateaus has a flat rectangular upper member 74. The bottom 70, entire plateaus 72 and upper member 74 are of porous material.
Frame 68 is mounted on a suction box 76 which extends below the bottom 70 of the frame. The suction box 76 has an orifice 78 which is adpated to be connected to a means, not shown, to evacuate the suction box 76.
In practice, a resistance heating element 38 is placed on each plateau 74, with the bends 42 and 44 overlapping opposite sides of the plateau. With the heating elements thusly positioned, and held into position by means not shown, the frame 68 is filled to a level above the resistance elements 38 with a slurry of water, binder, and inorganic fibers of the type described in U.S. Pat. No. 3,500,444 of W. K. Hesse et al. The liquid portion of the slurry is permitted to flow through the bottom 70 of the frame 68, and suction is used to withdraw the liquid portion of the slurry, thereby depositing the inorganic fibrous portion on the bottom 70. Further, the porous plateau 72 permits the passage of the liquid portion of the slurry, and the fibers will be deposited upon the resistance heating element 38 and the walls of the plateau. It will be noted in FIG. 4 that a plurality of plateaus 72 are employed to mold in situ a plurality of electrical heating elements 38. The block thus formed is thereafter removed from the frame 68 and dried.
Curved electrical heating elements, such as the elements 38A of the embodiment of FIG. 6 can be produced in a modified form of the production equipment of FIG. 4. To produce such elements, the upper member 74 of the plateau 72 must be curved to the contour of the heating element 38A.
Those skilled in the art will devise many uses for the present invention beyond those here disclosed. Further, those skilled in the art will devise modifications of the heating panels here disclosed within the scope of the present invention. For example, the present invention may be practiced with the heating elements using resistance wire in which the relatively straight portions between the first group of bends and the second group of bends are not parallel to each other, or may not be of equal lengths. It is therefore intended that the scope of the present invention be not limited by the foregoing disclosure but rather only by the appended claims.
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A thermal heating and insulating unit is manufactured by molding in situ a block of thermal insulating material about an electrical resistance element. The resistance element is first made from a continuous wire of electrical resistance material and formed into a serpentine configuration with a plurality of segments interconnected by bends at the ends of the segments. In a preferred construction, the segments are straight and the bends at the ends of the segments are in opposite directions. The resistance element is positioned in a mold on a plateau above a porous bottom, the bends overlapping the plateau, and a slurry of inorganic fibers, water and a binder is introduced into the mold to a lever above the plateau, the liquid component of the slurry passing through the porous bottom, and the fibers and a portion of the binder collecting on the porous bottom to form a block with a slot confronting the resistance element, the bends of the resistance element being embedded in the block. The block is then dried to produce a heating and insulating unit.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a Divisional application of application Ser. No. 10/906,119 filed Feb. 3, 2005, now published, of the same title, the disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to suction accumulators for refrigeration or air/conditioning system use and is particularly concerned with deflectors used with accumulators.
BACKGROUND OF THE INVENTION
[0003] Closed-loop refrigeration systems conventionally employ a compressor that is meant to draw in gaseous refrigerant at relatively low pressure and discharge hot refrigerant at relatively high pressure. The hot refrigerant condenses into liquid as it is cooled in a condenser. A small orifice or valve divides the system into high and low-pressure sides. The liquid on the high-pressure side passes through the orifice or valve and turns into a gas in the evaporator as it picks up heat. (Some systems operate in “transcritical” mode, in that the hot refrigerant is merely cooled in a high side heat exchanger, now termed a “gas cooler”, and turns to gas plus liquid as it passes through the expansion device.) At low heat loads, it is not desirable or possible to evaporate all the liquid in the evaporator. However, excess liquid refrigerant entering the compressor (known as “slugging”) causes system efficiency loss and can cause damage to the compressor. Hence it is standard practice to include a reservoir between the evaporator and the compressor to separate and store the excess liquid. It is also a reservoir for excess refrigerant, which is typically added to the system during manufacture to compensate for unavoidable leakage during the working life of the system. This reservoir is called a suction line accumulator, or simply an accumulator.
[0004] An accumulator is typically a metal can, welded together, and often has fittings attached for a switch, transducer and/or charge port. One or more inlet tubes and an outlet tube pierce the top, sides, or occasionally the bottom, or attach to fittings provided for that purpose. The refrigerant flowing into a typical accumulator will impinge upon a deflector or baffle intended to reduce the likelihood of liquid flowing out the exit, generally by removing kinetic energy from the liquid so it settles quietly into the reservoir area without churning or splashing. Some patents describe accumulators without deflectors (such as U.S. Pat. No. 5,179,844 and U.S. Pat. No. 5,471,854). However, the lack of a deflector reduces effective reservoir volume and reduces efficiency by allowing churning and splashing that returns unnecessary liquid to the compressor—that is, by allowing liquid carryover. Moreover, even when deflectors have been used in the past, the deflectors have contributed to turbulence, when the incoming fluid rebounds off the deflectors.
[0005] A consequence of using a suction line accumulator is that compressor oil can become trapped within it. Compressor oil is circulated with the refrigerant in most systems in current usage. Even if a separator is used, a small amount of oil escapes into the system. This oil will find its way into the accumulator, and while liquid refrigerant may be expected to evaporate and return to circulation as needed, the oil does not evaporate. Some means must be provided to return this oil to circulation. A known practice is to use a J-shaped outlet tube to carry the exiting gaseous refrigerant from the top of the accumulator down to the bottom and then back up to the outlet from the accumulator. A carefully sized orifice at the bottom of this “J-tube” (sometimes also referred to as a “U-tube”) entrains the oil from the bottom of the liquid area into the stream of exiting gas. A recent development in accumulator design is to incorporate a plastic liner in the accumulator to assist with the oil pick up function (as shown in U.S. Pat. Nos. 6,612,128 and 6,463,757).
[0006] While previous deflector and accumulator designs have considered configurations to help prevent liquid refrigerant from exiting the accumulator, the previous designs do not appear to have addressed deflector design to improve the separation of liquid from vapour (while maintaining little liquid carryover).
[0007] Deflectors within accumulators have typically been designed to act only as shields to protect an outlet tube (or a J-tube or a gas flow tube (all of which may be referred to as a conduit primarily for gas)) from stray liquid refrigerant. It would be desirable to have a deflector that improves the separation of liquid and gas, while also protecting the outlet (or gas flow tube) from liquid refrigerant.
SUMMARY OF THE INVENTION
[0008] Computational Fluid Dynamics (CFD) calculations were used to study the path of fluid entering an accumulator and its reaction with the deflector surfaces in greater detail than previously. This allowed for a more in-depth study of the critical features of the deflector surfaces, and led to embodiments of the present invention incorporating novel deflector designs with improved configuration of deflector surfaces to disperse a greater amount of kinetic energy, thereby yielding improved gas/liquid separation.
[0009] The geometry of an initial contact surface of a deflector according to one embodiment of the present invention provides for inbound refrigerant and oil to be separated into its liquid and gas components with minimal or less interaction with the initial contact surface. The liquid and gas are allowed only minimal interaction upon contact with the deflector to avoid or reduce the likelihood of liquid re-entrainment.
[0010] In an accumulator without a liner, the liquid refrigerant and oil are then directed towards or near an inner surface of the accumulator, where gravity pulls the liquid down.
[0011] In one type of liner-style accumulator, the liquid refrigerant is then directed to interior walls of a liner while the gas flows toward a gas flow conduit. The oil and liquid refrigerant flow downward due to gravity, along an inside surface of the liner, to the bottom of the liner, while the gaseous refrigerant migrates toward an inlet of the gas flow conduit. The gas flow conduit is designed to direct the gas downward, underneath the liner. As gas flows under the liner, oil is entrained within the gas flow, through an oil bleed orifice located at or near a zenith in the liner.
[0012] In accordance with another aspect of the present invention, a deflector is provided for an accumulator where deflector surfaces disperse a greater amount of kinetic energy (than previous designs), thereby yielding improved gas/liquid separation.
[0013] Embodiments of the accumulators and related designs described herein could be used in air conditioning systems within vehicles. Embodiments of the accumulators and related designs described herein could also be used in stationary air conditioning and/or refrigeration systems (commercial and industrial).
[0014] According to a further aspect, the invention provides an accumulator for an air conditioning system, the accumulator comprising an outer body, a liner inside and spaced from the outer body, a conduit primarily for gas, and a deflector comprising a generally cylindrical circumference with an inner surface, wherein the inner surface of the circumference of the deflector is adjacent an inside surface of the liner and the deflector further comprising a separation/protection means to separate liquid from gas, wherein a portion of the separation/protection means comprises a barrier to substantially prevent liquid from entering the conduit and a portion of the separation/protection means comprises an initial contact surface for directing fluid away from a flow of incoming fluid, wherein the initial contact surface is substantially convex across the initial contact surface and the initial contact surface, as seen from an upper edge to a lower edge thereof, is angled away from the flow of incoming fluid.
[0015] According to a further aspect, the invention provides an accumulator for an air conditioning system, the accumulator comprising an inlet to supply incoming fluid, the inlet being located on a side of the accumulator, the accumulator further comprising a deflector and a conduit primarily for gas, the deflector comprising a separation/protection means to separate liquid from gas, wherein the separation/protection means comprises a barrier to substantially prevent liquid from entering the conduit and the separation/protection means comprises an initial contact surface for directing fluid down and away from a flow of incoming fluid, wherein the initial contact surface is substantially convex across the initial contact surface and the initial contact surface, as seen from an upper edge to a lower edge thereof, is angled away from the flow of incoming fluid.
[0016] According to yet another aspect, the invention provides an accumulator for an air conditioning system, the accumulator comprising: a deflector, a conduit primarily for gas, an outer body, an inlet to supply incoming fluid, the inlet being located within a top of the outer body to direct incoming fluid downward, and a separation/protection means to separate liquid from gas, the separation/protection means comprises a barrier to substantially prevent liquid from entering the conduit and a portion of the separation/protection means comprises an initial contact surface for directing fluid down and away from a flow of incoming fluid, wherein the initial contact surface is located generally opposite the inlet and the initial contact surface is substantially convex across the initial contact surface and slopes downward and outward to direct fluid in a direction away from an entrance of the conduit, and the initial contact surface as seen from an upper edge to a lower edge thereof, is angled away from the flow of incoming fluid, and the barrier of the separation/protection means comprises a wall extending across the deflector, with the inlet being located on one side of the barrier and an opening of the conduit being located on the other side of the barrier.
[0017] Different embodiments of the present invention may provide some of the following features and advantages: an accumulator having a deflector where the deflector not only helps prevent liquid from flowing directly into a conduit for gas, but also helps separation of liquid from gas; a deflector for an accumulator, where the configuration of the deflector disperses kinetic energy to provide improved liquid/gas separation; a deflector for an accumulator designed to separate liquid from gas with less interaction between the liquid and gas or with less turbulence to avoid or reduce the likelihood of liquid re-entrainment with the gas; an accumulator having a gas flow tube inside the accumulator where an entrance to the gas flow tube is located near a top of the accumulator, thereby increasing the effective accumulator volume (because a greater volume of liquid can be stored in the accumulator without the liquid flowing into the gas flow tube); an accumulator providing improved performance; an accumulator which is relatively easy to manufacture and fits multiple installation configurations; an accumulator which is more cost-effective and more flexible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Preferred embodiments of the invention will now be described with reference to the attached drawings in which:
[0019] FIG. 1 a is a perspective view of a side-in-side-out (SISO) accumulator (with some of the internal components shown in dotted outline) in accordance with an embodiment of the present invention;
[0020] FIG. 1 b is a vertical sectional view of the accumulator of FIG. 1 a , with arrows showing the direction of flow within the accumulator;
[0021] FIG. 1 c is an exploded view of the accumulator of FIG. 1 a;
[0022] FIGS. 2 a - 2 f are different views of the SISO deflector of FIG. 1 a in which:
[0023] FIG. 2 a is a perspective view looking down;
[0024] FIG. 2 b is a perspective view looking up;
[0025] FIG. 2 c is a top view;
[0026] FIG. 2 d is a perspective sectional view;
[0027] FIG. 2 e is a bottom view looking up; and
[0028] FIG. 2 f is a side view of the initial contact surface;
[0029] FIG. 3 is a perspective sectional view of a top-in-side-out (TISO) accumulator in accordance with another embodiment of the present invention;
[0030] FIGS. 4 a - 4 d are different views of a TISO deflector for the accumulator of FIG. 3 in which:
[0031] FIG. 4 a is a perspective view;
[0032] FIG. 4 b is a perspective sectional view;
[0033] FIG. 4 c is a top view; and
[0034] FIG. 4 d is a bottom view;
[0035] FIG. 5 a is a perspective view of a TISO J-tube style accumulator, with a portion of the accumulator top and bottom canisters removed for greater clarity, in accordance with another embodiment of the present invention;
[0036] FIG. 5 b is a perspective view of the J-tube and deflector of FIG. 5 a;
[0037] FIG. 5 c is a perspective view of the J-tube and deflector of FIG. 5 b , from a different perspective;
[0038] FIG. 6 a is a perspective view of a SISO style accumulator, with a portion of the accumulator top and bottom canisters removed for greater clarity, in accordance with another embodiment of the present invention;
[0039] FIG. 6 b is a perspective view of the J-tube and deflector of FIG. 6 a.
DETAILED DESCRIPTION
[0040] As shown in FIGS. 1 a - 1 c , an accumulator 20 has an outer body or housing formed by a top canister 22 and a bottom canister 24 . The top canister 22 fits securely and sealingly with the bottom canister 24 . The combination, in this embodiment, of the top canister 22 and the bottom canister 24 may be referred to as an outer body. The top canister 22 comprises and inlet fitting 26 and an outlet fitting 30 . In this embodiment, both the inlet fitting 26 and the outlet fitting 30 extend from or are formed in the side(s) or surface of the top canister 22 . The inlet fitting 26 is adapted to accommodate an inlet tube 28 . The outlet fitting 30 is adapted to accommodate an outlet conduit (not shown). The bottom canister 24 is generally cylindrical, with a closed bottom or floor 34 and an open top.
[0041] Within the accumulator 20 are (among other possible features): a liner 36 , which is secured within the bottom canister 24 of the accumulator 20 ; a deflector 40 , which is secured near a top portion of the accumulator 20 ; and a gas flow tube or conduit 42 , which extends within the accumulator 20 , partway along the height of the accumulator 20 . The accumulator may also incorporate a desiccant container 44 .
[0042] As shown in FIG. 1 c , the liner 36 is generally cylindrical (which could also be considered to include a truncated cone shape, or an octagonal shape, or an oval shape or even a rectangular shape, for example), having an outer surface 46 , with a diameter slightly less than that of the bottom canister 24 . The top of the liner 36 is open. From the top of the liner 36 , the outer surface 46 of the liner 36 extends downward. Near a bottom portion of the liner 36 , the outer surface 46 extends inwardly to a nadir. From or near the nadir, the outer surface 46 extends inwardly and upwardly, to form a generally circular liner outlet or opening 50 . Formed within the liner 36 , advantageously at or near the nadir of the liner 36 , is an oil bleed orifice 52 (not shown). Extending along, and spaced evenly around the outer surface 46 of the liner 36 , are liner ribs 54 .
[0043] As suggested in FIGS. 1 a - 1 c , the deflector 40 is secured within the accumulator 20 . The defector 40 is shown in different views in FIGS. 2 a - 2 f . The deflector 40 has an outer wall (or circumference) 60 , having a generally truncated, conical shape, in this embodiment. The outer wall 60 could be considered generally cylindrical which could also describe many variations, including octagonal, oval, or rectangular shapes, for example. The deflector 40 has a lower portion 61 , which is indented by a step 62 . The outer wall 60 has an inner surface 63 .
[0044] The deflector 40 in this embodiment has an inlet entrance 64 , being generally u-shaped and projecting out from the outer wall 60 . The inlet entrance 64 could assume other shapes, provided that fluid entering the accumulator 20 is directed into the deflector 40 .
[0045] Two vertical deflector ribs 66 are shown extending outward from the outer wall 60 . The vertical deflector ribs 66 are adapted to ensure that the deflector 40 fits securely within the top canister 22 . Other or additional means could also be used to secure the deflector 40 within the top canister 22 .
[0046] An initial contact surface 70 (which may also be referred to as a separation/protection means) extends across a portion of the deflector 40 , from one portion of the inner surface 63 of the outer wall 60 to another portion of the inner surface 63 . The initial contact surface 70 , in this embodiment, is generally centered (in the left-right orientation, as seen in FIG. 2 c , for example) with respect to the inlet entrance 64 . A top (or upper) edge 73 of the initial contact surface 70 is approximately flush or even with a top edge of the deflector 40 . A lower edge 72 of the initial contact surface 70 creates a generally inverted U-shape. Although not shown, the lower edge 72 may have a beaded rim (or may be somewhat bulbous) to help liquid adhere to the edge 72 . The beaded rim helps to ensure that any liquid that adheres to the edge 72 is held on the rim and is directed towards the inner surface 63 and is not carried with the flowing gas. The lower edge 72 of the initial contact surface 70 may extend down at least as far, and, advantageously further, than a lower edge of the inlet entrance 64 of the deflector 40 . In a top view (looking down), the initial contact surface 70 has a slight arc, as shown, for example, in FIG. 2 c . In other words, from the perspective of incoming fluid, the initial contact surface 40 is convex (in the direction across the initial contact surface 40 ). As well, from a top edge 73 to the lower edge 72 of the initial contact surface 70 , the initial contact surface 70 is angled inward. In other words, the initial contact surface 70 , as seen from the upper edge 73 to the lower edge 72 , is angled away from the flow of incoming fluid.
[0047] A gas flow tube socket 74 is supported within the deflector 40 . In this embodiment, the gas flow tube socket 74 is part of deflector 40 , although it need not be. The gas flow tube socket 74 has an opening 76 , adapted to fit securely around a top portion of the gas flow tube 42 . A generally cylindrical wall 80 defines the socket opening 76 . A step 81 (as shown in FIG. 2 d ) may be formed within the wall 80 to form a stop or upper limit, against which an upper edge of the gas flow tube 42 may rest. The generally cylindrical wall 80 may extend upwardly into a flared upper surface 82 . In this embodiment, the socket 74 is secured within the deflector 40 by means of a support rib 84 (see FIGS. 2 a , 2 c and 2 e ), extending from the socket 74 to the inner surface 63 of the outer wall 60 , and by an extension 86 (see FIGS. 2 c and 2 e ) of the flared upper surface 82 which extends between the flared upper surface 82 and a windward side of the initial contact surface 70 .
[0048] The opening 76 of the socket 74 is located below the top edge 73 of the initial contact surface 70 .
[0049] Advantageously, the deflector 40 (and/or the top canister 22 ) may have a means known to those skilled in the art (not shown) to help ensure that the inlet tube 28 and/or the inlet fitting 26 is/are tightly sealed so that all fluid from the inlet tube 28 is directed into the deflector 40 .
[0050] The deflector may be made from a suitable plastic, metal, or other material. Advantageously, the material chosen for the deflector will have similar expansion properties as the material(s) used to manufacture the accumulator, so that both the accumulator and the deflector will expand or contract in a comparable manner in response to the application of heat or cold.
[0051] The accumulator 20 may be assembled as generally suggested by FIG. 1 c . The accumulator 20 may be assembled as follows. The desiccant container 44 is lowered into the liner 36 . The outer surface of the desiccant container 44 and the inner surface of the liner 36 are adapted to ensure that no fluid can flow between them. For example, the inner surface of the liner 36 may incorporate a small horizontal half bead (not shown), to provide a tight seal between the two surfaces. Many other techniques could be used to achieve the same result.
[0052] The gas flow tube 42 is then inserted through the opening formed within the desiccant container 44 . The outer diameter of the gas flow tube 42 is sized such that it is slightly smaller than the inner diameter of the opening formed within the desiccant container 44 , but still forms a tight seal between the two surfaces.
[0053] The deflector 40 then slides into position within the liner 36 . The lower portion 61 of the deflector 40 is sized to fit securely within a top portion of the liner 36 . A top edge of the liner 36 rests against the step 62 of the deflector 40 . The gas flow tube 42 fits securely within the opening 76 of the gas flow tube socket 74 . The flared upper surface 82 of the socket 74 reduces the pressure drop across the opening to the outlet tube 42 .
[0054] The liner 36 is then placed within the bottom canister 24 . There is a gap between an inside surface of the bottom canister 24 and the outer surface 46 of the liner 36 defined or determined (in this embodiment) by the extent to which the liner ribs 54 project from the outer surface 46 . The size of the gap may be adjusted. The larger the gap, the smaller the pressure drop through the accumulator 20 , at the expense of the volume within the liner 36 .
[0055] The top canister 22 is secured to the bottom canister 24 . Advantageously, there is a fitting or other adaptation (not shown) to help ensure a fluid-tight seal between a top edge of the deflector 40 and an inside surface of the top canister 22 . This helps prevent liquid carryover and may allow a top of the gas flow tube 42 to be near a top of the top canister 22 , thereby increasing the effective accumulator volume, because a greater volume of liquid can be held in the accumulator without the liquid entering the gas flow tube 42 . The top canister 22 is positioned on the deflector 40 such that the inlet entrance 64 of the deflector 40 meets up with and seals around inlet fitting 26 of the top canister 22 .
[0056] The top canister 22 and the bottom canister 24 may be made of aluminum or steel, for example, and welded together to form a hermetic seal.
[0057] In operation, fluid enters the accumulator 20 through inlet tube 28 . The arrows shown in FIG. 1 b illustrate the movement of the different components of the fluid. The fluid comprises liquid refrigerant, gaseous refrigerant and oil. The fluid entering the accumulator 20 flows against the initial contact surface 70 . Because the initial contact surface 70 is convex, liquid (refrigerant and oil) hitting the initial contact surface 70 and reflecting off it will be directed away from (that is, not directly towards) the stream of incoming fluid. Accordingly, the shape of the initial contact surface 70 helps to reduce re-entrainment of liquid into gas. As well, because the initial contact surface 70 is slanted or sloped inwardly from the top edge 73 to the lower edge 72 , liquid hitting the initial contact surface 70 and reflecting off it will be directed down. For liquid that flows along the initial contact surface 70 , gravity causes the liquid to flow down the initial contact surface 70 and then along the inverted U-shaped lower edge 72 until the liquid contacts the inner surface 63 of the outer wall 60 of the deflector 40 .
[0058] The design of the deflector 40 , as described above, dissipates kinetic energy and improves the degree to which gaseous refrigerant is initially separated from liquid refrigerant and oil. Moreover, the shape or geometry of the initial contact surface 70 provides improved liquid/gas separation with less turbulence and reduced re-entrainment of gas with liquid. In other words, the liquid fluid is separated from the gaseous fluid with relatively minimal interaction with the gaseous refrigerant to avoid liquid re-entrainment.
[0059] When fluid flows into the initial contact surface 70 , the liquid refrigerant and oil are directed down to the interior walls of the liner 36 , while the gaseous refrigerant is separated and directed towards the gas flow tube 42 . The oil and liquid refrigerant then flow downward due to gravity, typically along the inside surface of the liner 36 . The liquid refrigerant and oil pass through the desiccant container 44 , which removes moisture from the liquid refrigerant, and the liquid then settles on the floor of the liner 36 .
[0060] Meanwhile, gaseous refrigerant flows into the opening 76 of the socket 74 and then down and out the gas flow tube 42 below the liner 36 . The gaseous refrigerant then flows up through the gap between the liner 36 and the bottom canister 24 and then up to the outlet fitting 30 , whereupon, the gaseous refrigerant exits the accumulator though the outlet conduit (not shown). As the gaseous refrigerant flows past the oil bleed orifice (not shown) near the nadir of the liner 36 , oil (and possibly some liquid refrigerant) passing through the oil bleed orifice is entrained within the flow of gaseous refrigerant, and is carried up and out the outlet conduit (not shown) with the gaseous refrigerant.
[0061] The embodiments described above relate to a side-in-side-out (SISO) accumulator. However, the principles described above could also be applied to accumulators having other configurations. For example, a vertical, sectional view of a particular top-in-side-out (TISO) liner style accumulator is shown in FIG. 3 . Instead of the inlet tube 28 entering the accumulator 20 from the side, as in FIG. 1 a , FIG. 3 shows a TISO accumulator 90 , having an inlet tube 92 which enters the accumulator 90 from the top. The major differences between the SISO accumulator 20 of FIGS. 1 a and 1 b and the TISO accumulator of FIG. 3 are the location of the inlet tubes 28 and 92 and the configuration of the deflectors 40 and 94 , respectively.
[0062] Different views of the TISO deflector 94 are shown in FIGS. 4 a - 4 d . The deflector 94 has an outer wall (or circumference) 96 , which is generally cylindrical, with a slightly inwardly converging upper portion 100 , and a lower portion 102 , extending downward from a step 104 . Vertical external ribs 106 extend outwardly from the outer wall 96 . The outer wall 96 has an inner surface 110 .
[0063] A separation wall 112 extends across the deflector 94 , from one portion on the inner surface 110 to another portion on the inner surface 110 . The separation wall 112 has a wavy shape, as shown in the top view of FIG. 4 c . The wavy shape, in this embodiment, is designed to cooperate with the particular shape and placement of an inlet. Different embodiments may incorporate different shapes for the separation wall. A top edge of the separation wall 112 is generally flush with a top edge of the outer wall 96 .
[0064] An initial contact surface 114 extends between the separation wall 112 and the inner surface 110 of the outer wall 96 . The initial contact surface 114 , as described below, is shaped so that liquid on the initial contact surface 114 flows towards, and then down, the inner surface 110 of the outer wall 96 .
[0065] The combination, in this embodiment, of the separation wall 112 and the initial contact surface 114 may be referred to as a separation/protection means.
[0066] The initial contact surface 114 has an apex line (or ridge) 116 . In this embodiment, the initial contact surface 114 is generally symmetrical about the apex line 116 . Flow directing surfaces 118 and 120 are sloped both downward and towards the inner surface 110 of the outer wall 96 . An outer flow directing surface 122 is positioned between the separation wall 112 and the flow direction surface 120 , on each side of the apex line 116 . Each outer flow directing surface 122 is sloped downward and towards its corresponding flow directing surface 120 .
[0067] The overall shape of the initial contact surface 114 is substantially convex (in the direction across the initial contact surface 114 ), even though portions of the initial contact surface 114 may not be convex.
[0068] As shown in the top view of FIG. 4 c , fluid openings 124 are formed between the initial contact surface 114 and the inner surface 110 of the outer wall 96 . Edges of the initial contact surface 114 adjacent the fluid openings 124 may have beaded rims (or may be somewhat bulbous) to help liquid adhere to the rims, where the liquid is then directed toward the inner surface 110 (and away from the gas flow). As shown in the top and bottom views of FIGS. 4 c and 4 d , a socket 126 (of configuration similar to the socket 74 described above with respect to the SISO accumulator 20 ) is supported by the separation wall 112 and the underside of the initial contact surface 114 . The socket 126 has a socket opening 130 .
[0069] In operation, the deflector 94 and a top canister 132 of the accumulator 90 fit together so that the top edge of the separation wall 112 and the top edge of the outer wall 96 form a fluid tight seal against the top canister 132 (or against a fitting (not shown) within the top canister 132 ). Fluid from the inlet tube 92 is directed down into the accumulator 90 , between the separation wall 112 and the inner surface 110 of the outer wall 96 .
[0070] Fluid is directed towards the initial contact surface 114 , where gaseous refrigerant is mostly (or at least partly) separated from liquid refrigerant and oil. The gaseous refrigerant flows though the fluid openings 124 formed in the deflector 94 and then into the socket opening 130 and down the gas flow tube 42 and then proceeds as described above with respect to the SISO accumulator 20 . The liquid refrigerant and oil, upon hitting the initial contact surface 114 , flow down the initial contact surface 114 to the inner surface 110 of the outer wall 96 . The liquid refrigerant and oil then flow down the inner surface 110 and then down the inner surface of the liner 36 and then proceed as described above with respect to the SISO accumulator 20 .
[0071] The embodiments of deflectors described above relate to a particular type of liner-style accumulators. However, the principles described above could be applied to a liner style accumulator of any type. In those cases, the configuration of the deflector may be modified to accommodate the particular features of the different types of liner-style accumulators.
[0072] Moreover, the deflector design principles described above could also be applied to accumulators that do not incorporate liners. In other words, the principles described above could be applied to other situations where it would, for example, be desirable to separate gaseous fluid from liquid fluid with minimal (or less) re-entrainment of liquid fluid with gaseous fluid and/or with less churning of the separated liquid fluid. For a J-tube style accumulator, the deflector would be adapted to protect an inlet of a J-tube from liquid entering the accumulator. Because a J-tube style accumulator does not typically incorporate a liner, a deflector used in such a liner would likely be modified from the designs described above. For example, the outer wall 60 of the deflector 40 shown in FIG. 2 a could be modified for a J-tube style accumulator by flaring out the lower portion 61 so that the lower portion 61 engages (or comes close to engaging) an inner surface of the bottom canister 24 of the accumulator, so that liquid flowing down the inner surface 63 of the deflector 40 will be directed to the inner surface of the bottom canister 24 and be more likely to flow down the inner surface of the bottom canister 24 .
[0073] Alternatively, in an accumulator without a liner, it would not be necessary for a deflector to have a surrounding outer wall, such as outer wall 60 as shown in FIG. 2 a . In other words, in an accumulator without a liner, because it would be desirable to direct liquid to flow down an inner surface of the bottom canister 24 (as opposed to an inner surface of a liner), an outer wall of the deflector, such as outer wall 60 of the deflector of FIG. 2 a could be omitted.
[0074] An embodiment of one such SISO J-tube style accumulator is shown in FIGS. 6 a and 6 b . In this embodiment, fluid enters an accumulator 160 and hits the deflector 162 . The accumulator 162 has an inner surface 164 . Although perhaps not clear from FIG. 6 a , the bottom edge of the deflector 162 comes into contact with, or approaches the inner surface 164 of the accumulator 160 .
[0075] Similarly, a TISO accumulator without a liner could also use the concepts described above. For example, the deflector 94 shown in FIG. 4 a could be modified as required. The lower portion 102 in FIG. 4 a could be flared outward to approach or meet an inner surface of the bottom canister 24 . Alternatively, the outer wall 96 could be completely or partially omitted so that liquid, instead of being directed to the inner surface 110 of the deflector 94 , would be directed towards an inner surface of the bottom canister, as suggested in FIGS. 5 a - 5 c . An example of one such deflector is described as follows.
[0076] FIG. 5 a shows a J-tube style accumulator 138 , having a top canister 139 and a bottom canister 140 . The accumulator 138 incorporates a J-tube 144 (which could also be referred to as a U-tube). The accumulator 138 has an inner surface 142 . The accumulator 138 has a deflector 146 , having a separation wall 150 and an initial contact surface 152 . The deflector 146 in this embodiment is substantially similar to the combination of the separation wall 112 and the initial contact surface 114 of the TISO deflector 94 of FIGS. 4 a - 4 c . One difference between the embodiment of FIGS. 4 a - 4 c from the embodiment of FIGS. 5 a - 5 c , is that in the embodiment of FIGS. 4 a - 4 c , fluid reflecting off the initial contact surface 114 is directed towards the inner surface 110 of the deflector 94 . In contrast, fluid reflecting off the initial contact surface 152 of the deflector 146 of the embodiment of FIGS. 5 a - 5 c is directed to the inner surface 142 of the accumulator 138 .
[0077] The deflector 146 shown in the embodiment of FIGS. 5 a - 5 c is secured to the J-tube 144 . In different embodiments (not shown) the deflector could be secured to the top canister 139 or possibly the bottom canister 140 .
[0078] Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. For example, the embodiments of the accumulator designs described above have a single inlet. However, different embodiments could have more than a single inlet.
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A deflector for an accumulator for an air conditioning system acts as a barrier to substantially prevent incoming liquid from entering a conduit which is primarily for gas. Fluid entering the accumulator comprises gas and liquid. The deflector also assists with the separation of gas from liquid, with reduced turbulence, to decrease the likelihood of liquid becoming re-entrained within the gas. An initial contact surface of the deflector receives the incoming fluid. The initial contact surface is substantially convex, so that liquid reflecting off the surface will be travel in a direction away (or different) from the flow of incoming fluid. The initial contact surface is also angled to direct liquid reflecting off it (or flowing down it) downward and outward.
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BACKGROUND OF THE INVENTION
This invention relates to magneto ignition systems for small internal combustion engines of the type having a magnet in the flywheel or rotor that is driven in synchronism with the engine operation to generate the ignition spark through a primary and secondary winding coil arrangement in which the magnet generates primary current.
In a typical magneto ignition system of this type, the rotation of the rotor causes the magnet to induce a current in a primary winding that is located adjacent to the rotor or flywheel. This current flow is controlled by a switch device which allows the current to flow as the field from the rotor increases and which stops the current flow abruptly at a particular point in the engine cycle at which time a self-induced primary winding voltage is established. This produces a larger voltage, the ignition spark, upon a secondary winding that is electromagnetically coupled to the primary winding. In general, the spark voltage is related to the primary winding voltage in proportion to the turns ratio between the primary and secondary windings.
One form of a switch commonly used to control the primary winding current is simply a breakerpoint that is operated through the engine crankshaft to open and close at the proper times in the engine cycle to turn the current ON and OFF. At the time of opening, however, the self-induced primary winding voltage, which can be on the order of 400 volts or more, appears across the points, and despite the use of capacitors, there is gradual erosion or pitting of the contact surfaces. In addition, the rubbing block or interconnecting hardware between the breakerpoints and the engine output shaft also undergoes gradual wear. The wear and the point erosion can cause a gradual change in engine ignition timing and this gradual change in timing can result in loss of power and deteriorated fuel economy.
Consequently, semiconductor switch devices are also used to substitute for the breakerpoint arrangement since they are not subject to those mechanical problems. The function remains the same, however: to turn the primary winding current ON and OFF at the proper times during the engine cycle so as to produce the spark at or near the top of the compression stroke. It is also desired that the necessary advance characteristics for efficient engine combustion be provided. Proper switching requires that the primary current be allowed to build as the magnet field increases in the primary winding and that it is turned OFF near its maximum level so as to generate the largest possible ignition spark.
A transistor switch, however, is resistive and therefore tends to lower the maximum current flow in the primary circuit. Its resistance can be minimized, of course, by driving the transistor into saturation. But there is the problem, however, with those devices where the transistor switch is controlled by a bleed resistor between the collector and base input. The bleed resistor produces a voltage drop between the collector and base to insure operation of the transistor in its active region. But the result of this voltage drop is that the saturation voltage of the transistor is raised, which thereby reduces the primary winding current.
Some approaches attempt to avoid this problem by using a separate coil to generate the base drive for the transistor switch. In particular, the base drive coil is connected between the base and emitter of the transistor switch and produces a voltage in response to the flywheel rotation to place the switch in the active state to allow a current flow, that occurs in a phase relationship with the primary winding current since the base drive coil is wound on the same magnetic frame with the primary winding. This is also necessary to insure that the primary winding current reaches its maximum level. A problem associated with this arrangement, however, is that the coil must be constructed so as to have the capability to supply the necessary current from the magnet to excite the transistor into a saturated conducted state, which as mentioned previously, is necessary to achieve the maximum possible current flow. A power transistor is normally used and these are characterized by an extremely low base to emitter current gain characteristic. The need for a power transistor arises simply from the fact that the primary winding current can be comparatively high, for example, several amperes. Because of a power transistor's extremely low current gain characteristic, however, the base drive coil must be constructed to produce a significant amount of current. Thus the windings can be significantly large, which increases the overall size of the ignition system.
In other applications, a gate-turn off device is used instead of the simple power transistor. The advantage of the gate turn off device is its low active voltage drop which therefore maximizes the primary winding current. With this device, the bias winding is connected to the gate and the bias winding voltage generating the gate current to turn the switch ON, which allows the current to flow through the primary winding. When the bias winding output voltage drops below a particular negative level, the gate current is suddenly reversed which turns the switch OFF and thereby abruptly stops the current flow which produces the ignition spark in the same way discussed above.
The gate controlled switch, however, possesses some undesirable characteristics. Among these characteristics is that the current gain relationship between the gate input and the anode-cathode output, is such that more current is needed to turn the switch OFF than is needed to turn it ON. Consequently, the current gain, when the switch is conducting is much smaller than the current gain when the switch is not conducting. Because of this, the bias coil must be designed to have sufficient capability to supply the necessary current to turn the device off. The bias coil, therefore, is rendered somewhat larger than it might otherwise have to be if the current gain characteristics were uniform. The ignition system is thus larger also.
SUMMARY OF THE INVENTION
In the present invention, a Darlington current amplifier, consisting of at least two transistors, controls the current flow through the primary winding. This current amplifier consequently has very high and uniform current gain characteristics between its base input and its collector to emitter output. A separate drive winding drives the amplifier into saturation and, due to the amplifier's high gain characteristics, the drive winding is small. The voltage output from the drive winding is in phase with the primary winding voltage for the reason that both are wound on the same magnetic frame stator and thus, they share the same flux from the flywheel magnet that is housed in this engine flywheel. The drive winding is coupled through a diode to the base input of the Darlington and thus the amplifier is driven into saturation, as soon as the driver output exceeds the combined voltage drop of the diode junction and the base-emitter junctions of the two transistors. This, combined with the inphase relationship between the primary and drive voltages allows the primary current to increase to the maximum possible level as the flywheel is rotated.
A trigger winding which is mounted on the edge of the secondary and drive windings receives magnetic flux from the flywheel magnet independently from the stator. This produces a voltage output from the trigger winding that actuates a silicon controlled rectifier to its conductive state. The amplifier responds to the voltage across the rectifier output which is connected to the drive winding output. When the rectifier is conductive, its output circuit voltage drop is less than the voltage needed to turn the amplifier ON and thus it pulls the amplifier input below this voltage, thereby turning the amplifier OFF. This stops the current flow through the amplifier and produces a self-induced primary voltage which generates the spark pulse at the secondary voltage.
As the engine r.p.m. increases, the trigger coil voltage output reaches the SCR trigger voltage earlier in time for the reason that the rate of change in the flux from the flywheel is larger. As a result of this, there is a smooth and gradual ignition advance.
There is a deliberate interaction between the field produced by the primary winding current flow and the trigger coil. This field generates a small pulse in the trigger coil output in advance of the voltage pulse from the trigger coil that triggers the SCR. At low r.p.m., this pulse is at a level which is insufficient to trigger the SCR into its conductive state. At a particular high r.p.m., however, this pulse triggers the SCR into the conductive state. This occurs well in advance of the point at which there is sufficient primary winding current flow to establish the necessary ignition spark for sustained engine operation, and consequently, the engine cannot operate at or above this r.p.m.
The current flow from the drive winding into the amplifier is controlled by a resistor. When the primary winding current flow is stopped, energy is transferred from the primary winding to the secondary and drive windings. This energy produces a current flow in the drive winding that flows through the SCR which remains conductive until there is no drive winding voltage. The magnitude of the resistor determines the amount of the current flow in the drive winding induced by the primary winding field, which thereby determines the amount of energy which is transferred to the secondary winding and the maximum obtainable secondary voltage.
Thus, an object of the present invention is to provide an extremely compact breakerless magneto which can be placed, as a single sealed unit, adjacent to the flywheel of a small internal combustion engine, and which produces the spark with minimum circuit electrical losses.
Other objects of the present invention include: providing an ignition system which prevents excessive engine r.p.m., and which regulates the open circuit secondary voltage so as to prevent damage to the magneto structure; providing an ignition system in which the necessary components are as small as possible by maximizing the efficiency of the system components so as to achieve an extremely small and economical ignition system and one that is easy to fabricate and readily adaptable for varying engine installations.
The foregoing, as well as other objects, features and benefits of this invention will be apparent to those skilled in the art from the following drawing, detailed description and claims.
DESCRIPTION OF THE DRAWING
FIG. 1 shows the various coil windings of the present invention in cross section on a three legged stator structure in a position adjacent to a typical flywheel that is mounted on the crank shaft of an internal combustion engine. A portion of the flywheel is cutaway to expose the magnet and pole shoes.
FIG. 2 is an enlargement of the flywheel and magnet piece, and the windings and stator frame shown in FIG. 2, so as to show more clearly, their positional and dimensional relationships.
FIG. 3 is an electrical schematic of the ignition system of the present invention.
FIG. 4 shows the wave forms for the trigger coil, primary winding and secondary output with respect to particular points in the flywheel cycle. FIG. 4 shows the output wave forms for the trigger coil and primary winding current at normal r.p.m., and at and above which the ignition system provides automatic governing.
DETAILED DESCRIPTION
Proceeding now with the detail of the operation of the present invention, reference is made first to FIG. 1, where a typical installation of a magneto employing the present invention is shown on an engine. The engine flywheel, designated 10, is mounted on the engine crankshaft and is rotated in the direction shown by arrow A. Flywheel 10 contains a magnet designated 12, that is located in the interior of the flywheel 10, and adjacent to each edge of magnet 12 there are pole shoes 14, 15, extending radially outward from the edge of flywheel 10. These shoes 14, 15 are constructed of laminations of high permeability material and serve to deflect or orient the field lines from the magnet in a substantially radial direction, and so, the lines can be perceived to originate from one end of the magnet 12, passing through shoe 14 in the radial direction and then bend slowly in a circular direction to enter shoe 15 and terminate in the opposite end of the magnet 12.
Located adjacent to flywheel 10 is a magnetic stator frame designated 16 having three legs 16a, 16b and 16c extending into close proximity to the edge of flywheel 10. The air gap 17 between the legs 16a, 16b, 16c and flywheel 10 should be as small as possible to minimize field losses between the pole shoes 14, 15 and the stator frame 16.
A first winding 18, hereinafter referred to as the primary winding, is wound around the center core leg 16b. Wound concentrically around primary winding 18 is the secondary winding 20 which produces ignition spark across gap 25. Also wound around the center leg 16b is a third winding hereinafter designated the drive or bias winding 22. Both the secondary winding 20 and drive winding 22 are magnetically coupled to the primary winding 18 due to their close distal relationship. Moreover, by reason of their common concentric position on leg 16b, the primary and secondary drive windings 18, 22 are penetrated by the same magnetic flux in the stator frame 16 and thus the voltages that are induced in each winding, 18, 22 as flywheel 10 rotates are in phase.
The size of the windings 18, 20, 22 depicted in the cross sections in FIG. 1 and FIG. 2 represents the relative number of turns in each winding. Secondary winding 20 is thus larger than the primary winding 18 since it must have many more turns than primary winding 18 to provide the needed transformer relationship to generate the ignition spark from the self-induced primary voltage. Drive winding 22 produces a small signal and thus is small as shown.
A fourth coil, hereinafter referred to as trigger coil 24, is located on the lower edge of secondary winding 20 and drive winding 22, in close proximity to flywheel 10 so that the field from pole shoes 14, 15 penetrate it as flywheel 10 rotates. A core 24a of high permeability material is provided for the purpose of intensifying the field. Trigger coil 24 and primary winding 18 are comparatively close to each other, as it can be seen, and as a result, the field produced by the high primary current penetrates trigger coil 24. As discussed in greater detail below, this produces the automatic governing control of the present invention. Although there is some interaction with the drive winding 22 and secondary winding 20, the lower current levels in these windings produce much smaller fields, having no noticeable effect on the performance of the ignition system.
As flywheel 10 rotates in the direction of arrow A the field flux that passes between pole shoe 14 and pole shoe 15 produces the maximum flux density in leg 16b when pole shoe 14 is essentially directly opposite leg 16b and pole shoe 15 accordingly is essentially opposite leg 16c. Likewise, there is maximum flux density in 16b, but in the opposite direction when the flywheel 10 is rotated, so that shoe 14 is opposite leg 16a and shoe 15 is opposite leg 16b. These changes in flux density and direction in stator frame 16 and, more precisely in leg 16b, induces voltages in primary winding 18 and drive winding 22 for the generation of the ignition spark in the manner discussed below.
At this juncture it should be observed that the field in stator frame 16 is concentrated in the frame and does not interact with trigger coil 24. The field magnet 12, however, penetrates the trigger coil 24 and produces the main trigger pulse for controlling the point in the engine cycle at which the spark occurs.
Referring now to FIG. 2, the structure of the various windings with respect to each other is shown in greater detail. It should be observed that the distance between the edges A & B on stator leg 16a should be ostensibly equal to the distance between edges C & D on pole shoe 14. Likewise, these distances are also the same as the distances between edges E & F on pole shoe 15 and the distance between edges G & H on legs 16b and 16c. In other words, the width of the pole shoes should be substantially the same as the distance between the stator legs. This has been found to be desirable to insure that the wave forms shown in FIG. 4 are produced.
Turning now to FIG. 3, it can be observed once again, that primary 18, secondary winding 20 and drive winding 22 are wound upon and magnetically coupled to each other through stator leg 16b. The dotted line, desingated 16, corresponds to the stator frame. The output terminals from secondary winding 20 are connected to spark gap 25, corresponding, for illustrative purposes, to the engine spark plug, across which the induced secondary output generates the high tension voltage for ignition spark for fuel combustion for sustained engine operation. One output terminal of primary winding 18 is coupled to ground and likewise one terminal of secondary winding 20, drive winding 22 and trigger coil 24 is connected to ground. The output from primary winding 18 is connected across the collector and emitter junctions of a Darlington transistor amplifier designated 26, which includes at least two transistors T1, T2, thereby giving amplifier 26 an extremely high current gain characteristic between the base of transistor T1 and the output transistor T2. Resistors R1 and R2 provide leakage current between the collector and base junctions of transistors T1 and T2 to maximize the transistor cutoff voltage. The cutoff voltage of T1 and T2 determines the maximum obtainable primary voltage. Hence, increasing the cutoff voltage increases the primary voltage and the spark voltage it produces at the secondary voltage. Also connected across the collector and emitter junctions of amplifier 26 is a diode D1 to accommodate reverse primary current at certain points in the engine cycle.
The output of drive winding 22 is fed to the base of T1 through a diode D2. A silicon controlled rectifier SCR 1 is connected between the junction of winding 22 and D2 and ground. Trigger coil 24 is coupled to the gate of SCR 1 and renders it conductive at an appropriate point in the engine cycle, which thereby clamps the junction voltage to the anode-cathode voltage drop of SCR 1, which is about 0.9 volts. Diode D2 raises the voltage necessary to render transistors T1 and T2 active to approximately 1.8 volts. This is the total voltage drop across D2 and between the base of T1 and the emitter of T2. When the junction voltage is greater than 1.8 volts, amplifier 26 is on. If it is less, the amplifier is full OFF.
At position line 1, the flywheel position at which pole shoe 14 is substantially opposite leg 16b, there is maximum flux density in stator 16 passing between legs 16b and 16c. Since dφ/dt is zero at this time, the reverse primary current flow drops to zero. As pole shoe 14 moves from this position, a positive voltage is generated on primary winding 18 and a positive voltage is produced on the anode of SCR 1 from the drive winding 22. When the anode voltage exceeds approximately 1.8 volts, T1 and T2 are drive into a high current saturated state since there is no base current limiting resistor. The primary current then rises due to the increasing primary voltage and drive coil signal and reaches its maximum at or near position line 2, which is approximately the position of flywheel 10 in FIGS. 1 & 2. Between positions 1 & 2, it can be seen that the trigger output rises from a negative value through zero to a positive value designated as pulse A. Pulse A is a product of the flux from pole shoe 14 that penetrates trigger coil 24 with decreasing density as the shoe is rotated towards the coil.
At position 2, the trigger coil output reaches a level designated trigger voltage as shown by the dotted lines. At this level the gate of SCR 1 conducts to turn SCR 1 on. The output circuit characteristics of SCR 1 are essentially those of a diode: A constant voltage of about 0.9 volts and low resistance. Thus consequently the anode is clamped to 0.9 volts when SCR 1 is ON. Thus T1 & T2 are back-biased and suddenly turned OFF causing the primary current flow to stop. Capacitor C1, however, acts as a time delay and allows the current to continue to flow for a brief moment after position 2. Thus the current gradually decays to the lower level depicted after position 2. The primary voltage that is developed is a product of the rate of current change in the primary winding. Hence, although the primary voltage has not been shown in FIG. 4, it is axiomatic that as the current decays rather quickly just after position 2, a self-induced voltage appears on the primary, which is stepped up in the secondary to produce the spark pulse that is shown.
The primary winding frequency response is substantially higher than the frequency response of the secondary winding. For well-known reasons, capacitor C1 lowers the frequency response of the primary circuit so that more of the induced primary voltage is transferred to the secondary winding. Thus, more energy is transferred to the secondary. A substantial portion of this energy would otherwise be lost in the higher components of primary voltage. Capacitor C1, therefore, serves to increase the secondary spark voltage.
SCR 1 stays on until the drive winding 22 voltage drops substantially to zero. This is a characteristic of silicon controlled rectifier. The self-induced voltage on primary winding 18 produces a voltage on drive winding 22 and this voltage gives rise to current through R3 and SCR 1. This is in addition to the current produced by the flywheel magnet movement creating the drive winding signal. The magnitude of this current is determined, of course, by resistor R3. The current level determines the amount of electromagnetic energy in the primary field at position 2, when the current is maximum, just before turn OFF, it is likewise equated. Thus, by increasing the current in the drive winding, more energy is transferred to it from the primary. This lowers the maximum available net energy that can be stored in the secondary field when the spark current is developed. Since the secondary voltage and energy are directly related through the above equation, R3 can be selected to develop enough current in drive winding 22 to hold the secondary voltage below the voltage which could cause damage to the secondary winding if it is accidently open circuited.
From the wave forms in FIG. 4 and also from FIG. 2, it can be appreciated that the position of trigger coil 24 on the edge of secondary winding 20 and drive winding 22 determines at what point in the rotation of rotor 10 it will reach the trigger voltage. That is, moving it away from the direction of arrow A will cause it to reach the trigger voltage at a point after position 2, thus retarding the timing. As engine r.p.m. increases, the rate at which the flux lines from magnet 12 permeate trigger coil 24 also increases. This increased rate of flux penetration increases dφ/dt and hence, the trigger level is reached before position 2 as engine r.p.m. increases. An ignition advance is thus achieved, whereby the spark occurs earlier in the engine cycle. This is necessary for economical and efficient engine operation due to the response time of the air/fuel mixture.
Attention is now directed to those wave forms showing the operation of the engine at and above the governed r.p.m. First it should be noted that the trigger output at low r.p.m. has a small positive pulse, designated pulse B that appears at position 1. This results from the field from the primary winding current that is flowing in the negative direction at that time. This interaction results from the field flux lines that penetrate trigger coil 24. Below the level designated "governed r.p.m.", pulse B is substantially less than the trigger voltage and consequently has no effect upon the operation of SCR 1. As engine r.p.m. increases, however, the rate at which the primary winding current changes also increases along with greater current. As a result, the level of pulse B rises. At the governed r.p.m., pulse B reaches the trigger level and triggers SCR 1 into its conductive state. However, at position 1, the primary current is small and close to zero so no appreciable self-induced primary voltage is generated. Hence, a spark is not generated and combustion does not take place. Engine operation above this r.p.m. is therefore impossible and over-revving is thereby prevented.
While that which has been described previously is the preferred embodiment of the present invention, from the analysis of its operation, it will be obvious to those skilled in the art that there are many possible modifications that can be made to the preferred embodiment, which nonetheless would still embrace its true scope and spirit of the invention. The following claims are intended, therefore to cover all such equivalents, modifications and variations.
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A breakerless magneto ignition system for an internal combustion engine, having an inherent speed limiting feature is disclosed. The ignition system includes an ignition coil with primary and secondary windings, a drive winding and a trigger winding. A first solid state switch is placed in circuit with the primary winding for controlling current flow through the primary winding, the drive winding controlling the solid state switch to render it conductive to allow current flow through the primary winding, and the trigger winding and an associated switching circuit subsequently shunting the input to the first solid state switch to render it nonconductive, to block current flow through the primary coil and induce an ignition spark voltage in the secondary winding. The primary winding, secondary winding and drive winding are mounted on the same magnetic frame adjacent a magnet-containing flywheel, and the trigger coil is mounted on the lower edge of the secondary winding in close proximity to the flywheel. The primary winding current generates a field that interacts with the trigger winding to produce a premature pulse which increases in magnitude to prematurely activate the first solid state switch at a high engine RPM, at a point in the engine cycle at which there is insufficient current flow in the primary coil to produce an effective ignition spark voltage.
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RELATED APPLICATIONS
Not Applicable.
FIELD OF THE INVENTION
The present invention relates generally to portable tree stands, and in particular, to a length adjustable step that is attachable to portable tree stands for use in hunting.
BACKGROUND OF THE INVENTION
Over the years, modern advances in hunting equipment have enhanced the sport, providing hunters with increased success. Although many of these products are high-technology devices, some products are amazingly simple. An example of one (1) of these products is the tree stand. A tree stand is used to form a stable surface in a tree upon which the hunter may sit or even stand. It allows the hunter to remain elevated and nearly invisible to his prey for long periods of time in relative comfort.
However, access into and out of such tree stands rely on the hunter climbing or “hugging” the tree in order to access the elevated seat. While perhaps not a problem for young hunters, disabled or elderly hunters have a difficult time. While ladders, step stools and the like can be used, these items are heavy and must be transported into and out of the hunting spot perhaps forcing multiple trips. Accordingly, there exists a need for a means by which a hunting tree stand may be more easily accessed without the disadvantages as described above.
SUMMARY OF THE INVENTION
In view of these disadvantages, the inventor has recognized a lack in the art and observed that there is a need for an attachable step and a method of attachment for use with portable tree stands. The development of the present invention, which will be described in greater detail herein, substantially departs from conventional solutions to provide a new portable tree stand step and in doing so fulfills this need.
In accordance with features and aspects of one exemplary embodiment consistent with the principles of the present disclosure, a portable tree stand step is provided that can include a length of rope having a first end, an opposing second end, and a center disposed between the first end and the second end. A first slide fastener is connected to the rope first end having a plurality of apertures to receive and frictionally retain the rope. A second slide fastener is connected to the rope second end also having a plurality of apertures to receive and frictionally retain the rope. A first foot pad is attached to the rope between the first end and the center. The first footpad includes a generally rectangular section of flexible strap material, a pair of apertures disposed through opposing ends of the strap material, and a grommet fastened to a perimeter of each of the pair of apertures. A second foot pad is attached to the rope between the second end and the center. The second footpad also includes a generally rectangular section of flexible strap material, a pair of apertures disposed through opposing ends of the strap material, and a grommet fastened to a perimeter of each of the pair of apertures. The first end is configured to loop around a first side of a lower frame of a portable tree stand and is securable to the first slide fastener. The second end is configured to loop around an opposing second side of the lower frame of the portable tree stand and is securable to the second slide fastener. The rope center is configured to loop around a middle location of the lower frame of the portable tree stand to define a first step and a second step. The first foot pad is disposed at a middle portion of the first step and the second footpad is disposed at a middle portion of the second step.
Furthermore, the described features and advantages of the disclosure may be combined in various manners and embodiments as one skilled in the relevant art will recognize. The disclosure can be practiced without one (1) or more of the features and advantages described in a particular embodiment.
Further advantages of the present disclosure will become apparent from a consideration of the drawings and ensuing description.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages and features of the present disclosure will become better understood with reference to the following more detailed description and claims taken in conjunction with the accompanying drawings, in which like elements are identified with like symbols, and in which:
FIG. 1 is an environmental view of a portable tree stand step depicted in-use as attached to a portable tree stand, in accordance with the present invention;
FIG. 2 is an environmental view of the portable tree stand step depicted in-use, in accordance with the present invention; and,
FIG. 3 is a perspective view of the portable tree stand step depicted as attached to the portable tree stand, in accordance with the present invention.
DESCRIPTIVE KEY
10 portable tree stand step
20 a first step
20 b second step
21 rope
22 a first side attachment loop
22 b second side attachment loop
24 center attachment loop
26 a first knot
26 b second knot
26 c center knot
30 a first foot pad
30 b second foot pad
32 grommet
35 length adjustment fixture
100 tree stand
102 lower frame
105 hunter
110 tree
115 ground surface
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In accordance with the invention, the best mode is presented in terms of certain embodiments, herein depicted within FIGS. 1 through 3 . However, the disclosure is not limited to the described embodiments and a person skilled in the art will appreciate that many other embodiments are possible without deviating from the basic concept of the disclosure and that any such work around will also fall under its scope. It is envisioned that other styles and configurations can be easily incorporated into the teachings of the present disclosure, and only one particular configuration may be shown and described for purposes of clarity and disclosure and not by way of limitation of scope.
It can be appreciated that, although such terms as first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one (1) element from another element. Thus, a first element discussed below could be termed a second element without departing from the scope of the present invention. In addition, as used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It also will be understood that, as used herein, the term “comprising” or “comprises” is open-ended, and includes one or more stated elements, steps or functions without precluding one or more unstated elements, steps or functions. Relative terms such as “front” or “rear” or “left” or “right” or “top” or “bottom” or “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one (1) element, feature or region to another element, feature or region as illustrated in the figures. It should be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. It should also be understood that when an element is referred to as being “connected” to another element, it can be directly connected to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” to another element, there are no intervening elements present. It should also be understood that the sizes and relative orientations of the illustrated elements are not shown to scale, and in some instances they have been exaggerated for purposes of explanation.
Referring now to FIGS. 1 through 3 , depicting a portable tree stand step, identified generally by reference to a device 10 , where like reference numerals represent similar or like parts. In accordance with the teachings of the present disclosure, the device 10 generally provides an attachable step to assist hunters 105 as they climb into and out of a tree stand 100 .
Referring first to FIGS. 1 and 2 , which depict the device 10 in progressive in-use states. The device 10 is preferably made of a section of flexible rope 21 forming a length-adjustable first step 20 a and second step 20 b . The steps 20 a , 20 b are fastened to front end of a lower frame 102 of the tree stand 100 . During use, the tree stand 100 is commonly positioned at approximately from waist height to shoulder height above a ground surface 115 . The steps 20 a , 20 b support a hunter's boot at an approximate knee-high position above the ground surface 115 to allow the hunter to step onto and off from the tree stand 100 . The flexible nature of the device 10 allows the steps 20 a , 20 b to adjust to a suitable size and shape to receive a large hunting boot while the hunter 105 climbs into the stand 100 .
Referring next to FIG. 3 , the device 10 includes a first step 20 a which is formed by a first side attachment loop 22 a and a first foot pad 30 a . In a similar manner, the second step 20 b is formed by a second side attachment loop 22 b and a second foot pad 30 b . The length of flexible rope 21 creates the steps 20 a , 20 b and side attachment loops 22 a , 22 b and is preferably approximately three-eighths inch (⅜ in.) in diameter. The rope 21 is fabricated using traditional materials such as hemp, nylon, or the like. The side attachment loops 22 a , 22 b provide for attachment of the respective steps 20 a , 20 b to opposing sides of the lower frame 102 of the tree stand 100 . Each side attachment loop 22 a , 22 b includes a length adjustment fixture 35 which provides for independent adjustment of the length of each side attachment loop 22 a , 22 b , to varying a distance at which the respective first foot pad 30 a and second foot pad 30 b are suspended above the ground surface 115 .
Opposing ends of the rope 21 are looped around opposing sides of the lower frame 102 of the tree stand 100 . Each end of the rope 21 is routed through a respective length adjustment fixture 35 to produce an arresting friction attachment and is secured using a respective first knot 26 a and second knot 26 b . The length adjustment fixture 35 is preferably a slide fastener similar to a fastening device used on tents, awnings, and the like which utilize devices such as runners, toggles, and the like to adjustably secure the ends of the rope 21 to the body of the rope to adjust each step 20 a , 20 b at a desired height.
The rope 21 is also attached to the lower frame 102 at an intermediate frontal position by forming a center attachment loop 24 at a midpoint of steps 20 a , 20 b . The center attachment loop 24 is secured tightly to the lower frame 102 using a center knot 26 c . Although the steps 20 a , 20 b are illustrated here at approximately the same suspended length, it can be appreciated that one step 20 a , 20 b can be positioned above or below the other step 20 a , 20 b , thereby providing the hunter 105 with a two-step method of climbing onto the tree stand 100 .
The footpads 30 a , 30 b are generally flat, rectangular sections of heavy-duty nylon strapping material approximately six inches (6 in.) to eight inches (8 in.) in length by approximately two inches (2 in.) in width. Each foot pad 30 a , 30 b includes a pair of integral metal grommets 32 positioned adjacent to each opposing end. The rope 21 is routed through the grommets 32 along a bottom surface of the footpads 30 a , 30 b to form the stepping loop of each step 20 a , 20 b where the footpads 30 a , 30 b provide a stable centralized stepping surface. It is further envisioned that the materials used to make the various parts of the device 10 be of a black or camouflage color to avoid being noticed by game animals.
The lightweight nature of the device 10 allows easy carrying by the hunter 105 or alternatively to remain attached to the tree stand 100 , if desired, during the trek into and out of a hunting area. The use of the device 10 provides hunters 105 who hunt from tree stands 100 a method of easily accessing the stand 100 and is envisioned to be especially useful for hunters 105 having physical limitations or weakness in their legs.
It can be appreciated by one skilled in the art that other styles and configurations of the present invention can be easily incorporated into the teachings of the present disclosure and only certain particular configurations have been shown and described for purposes of clarity and disclosure and not by way of limitation of scope.
In accordance with the principles of the present invention, the device 10 can be installed and utilized by the user in a simple and effortless manner with little or no training in general accordance with FIG. 1 through FIG. 3 . It can be appreciated that the steps required to install and utilize the device 10 , as described, can performed in alternative order and as such should not be viewed as a limiting factor.
The method of installing and utilizing the device 10 can be achieved by performing the following steps: procuring a model of the device 10 having a desired camouflage color; installing the footpads 30 a , 30 b upon interior portions of the rope 21 corresponding to the position of respective loop steps 20 a , 20 b , if not previously installed, by routing the rope 21 through the grommets 32 ; attaching the device 10 to an installed tree stand 100 positioned between waist height and chest height by forming the center attachment loop 24 by looping an intermediate portion of rope 21 around a front middle portion of the lower frame 102 and securing thereto using a center knot 26 c ; attaching ends of the rope 21 to opposing sides of the lower frame 102 to form the steps 20 a , 20 b ; securing the side attachment loops 22 a , 22 b around the sides of the lower frame 102 by routing ends of the rope 21 around the lower frame 102 and through apertures of the respective length adjustment fixtures 35 ; affixing the length adjustment fixture's 35 in position upon the rope 21 by tying respective first 26 a and second 26 b knots; adjusting a hanging length of each step 20 a , 20 b individually by sliding the respective length adjustment fixtures 35 along the length of the rope 21 to increase or decrease the length of the respective side attachment loop 22 a , 22 b until obtaining a desired length of each step 20 a , 20 b ; utilizing the device 10 to enter the tree stand 100 by inserting one foot into one of the steps 20 a , 20 b ; inserting a remaining foot into the remaining step 20 a , 20 b ; and, stepping up onto the tree stand 100 .
The foregoing descriptions of specific embodiments have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention and method of use to the precise forms disclosed. Various modifications and variations can be appreciated by one skilled in the art in light of the above teachings. The embodiments have been chosen and described in order to best explain the principles and practical application in accordance with the invention to enable those skilled in the art to best utilize the various embodiments with expected modifications as are suited to the particular use contemplated. It is understood that various omissions or substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but is intended to cover the application or implementation without departing from the spirit or scope of the claims of the invention.
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A portable tree stand step providing assistance to hunters when entering and exiting hunting tree stands includes a rope fastened to a lower frame of the tree stand. The rope forms a pair of flexible stepping loops that hang downwardly and into which the hunter can step, thereby allowing the hunter to enter the tree stand. Additionally, each stepping loop of the portable tree stand step is supplied with a foot pad and a length adjustment mechanism, allowing the hunter to position and securely step upon the foot pad when entering the stand.
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BACKGROUND OF THE INVENTION
The present invention relates to an electrical safety iron that increases safety while ironing clothes or other fabric. The iron prevents a fire that might be caused by the overheating of the object being ironed; such overheating could overheat an insulation means, such as a cushion, location underneath the fabric being ironed and eventually produce a major fire. The ability of an iron to overheat and cause a major fire is due in part by the lack of a safety device incorporated in an iron to prevent overheating, particularly when the iron is in its ironing position. The present invention incorporates an electric circuit which makes it possible to quickly cut off heat to the iron by terminating power to the iron after a predetermined time limit following suspension of an ironing operation.
SUMMARY OF THE INVENTION
The present invention provides a safety iron having a hand grip designed for manual holding, considering the structure of the palm as well as associated ergonomics such that the operator will feel comfortable using the iron. Structurally, the grip is hollow and contains a push-button main control switch in the forward area thereof incorporating two sets of ON/OFF contacts within, one set normally closed, the other set normally open. A switch plunger is mounted to the top area of the grip and fits within a recess in the grip in a manner whereby it may be pivoted about a fixed axis to operate the switch. The front of the plunger is in contact with the push-button of the main control switch but normally does not actuate the switch. To operate the iron, the user's hand holds the grip tight to pivot the plunger to close an open switch and to open a closed switch to control energization of the heater electrical circuit. When the force exerted by the operator's palm is released from the grip, the push-button of the control switch will be released forthwith to reset the contacts, thereby cutting off power to the iron.
The safety iron device structured according to the present invention further incorporates a hollow cylinder or tube interconnecting the iron body section with the grip. The cylinder is made of insulating material so as to prevent passage of the heat produced by the body section to the grip. A compression spring in the interconnecting cylinder is positioned adjacent the grip. A movable support rod comprising a base having a locking groove in a central area along its length and a tapered top area fits within the cylinder against the spring with the latter in compressed condition biasing the rod toward the iron body. The support rod is locked in position by a locking pin controlled by a solenoid.
The safety iron device structured according to the invention further incorporates a number of current control switches for controlling the power input to the heater of the iron. The locking pin constitutes the solenoid plunger and a spring biases the locking pin into engagement with the groove of the movable support rod when the solenoid is not energized. By retracting the locking pin from the locking groove of the support rod by energizing the solenoid, the support rod will be extended below the iron body by the compression spring to lift the iron relative to an underlying support surface and a fabric being ironed while simultaneously the electrical energy to the iron heater is cut off.
The safety iron device structured according to the present invention further incorporates a push-button override switch on the heel of the grip so that setting the iron to stand on its rear side on the grip heel causes the weight of the iron to depress the push-button override switch to close the heating circuit even if the main control switch is not closed. Thus, the iron produces heat for ironing and the push-button switch is arranged to automatically reset while the iron is in service, although the heater is normally controlled through the main switch in the grip.
To achieve a smooth control of all the functions mentioned above, the present invention provides a novel electronic control circuit. The controller comprises a delayed triggering circuit composed of an integrated chip and solenoid circuit. Input power to both circuits goes through a step-down transformer and a full-wave diode rectifier to produce an output power supply.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an iron embodying the invention;
FIG. 2 is an exploded view of the iron illustrating the support and lifting system;
FIG. 3 is a mid-section view of the iron;
FIG. 4 is similar to FIG. 3 with the support system extended;
FIG. 5 shows the iron supported and in an upright position; and
FIG. 6 is a schematic view of the preferred control circuit for the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the accompanying illustrations, the safety iron of the present invention comprises a body section 14 having a hollow grip section 1 connected to the body section by means of a tubular member 13, with both the tubular member and the grip being made of insulation materials.
As shown in FIGS. 1 and 3, in the hollow portion of the forward section of the grip section 1, there is mounted a main control switch 3 having one set of normally closed contacts SW1 and one set of normally open contacts SW2 as shown in FIG. 6. The grip is arranged so that the switch plunger 2 engages switch 3. The plunger 2 rotates about bearing shaft 4 whereby, in operation, the grip section 1 is held in one hand with the thumb pressing against the plunger to depress the push-button of the switch 3 to close SW2 and open SW1. Depression of switch 3 thereby closes the electrical AC circuit to energize heating coil 6. The open SW1 inactivates the time delay control circuit for the iron, which will be described in more detail below. Hence, by depressing plunger 2, the heating coil 6 continues to discharge the necessary heat required to iron fabrics.
Referring to FIG. 3, an interconnection tube 13 is made of insulating material and contains a main compression spring 11 adjacent the grip 1 for biasing cylindrical rod 9 disposed in the hollow core of the tube 13 toward the iron body. The underside of the movable support rod is enlarged in the shape of a disk 91 that fits flush in an enlarged opening or recess in the bottom of the iron body when rod 9 is in its retracted position within the core of the tube 13. The cylindrical shaft area of the movable support rod 9 includes an annular undercut groove 92 to accommodate a locking pin 10 constituting a plunger of a control solenoid 7. The locking pin 10 is normally biased toward rod 9 by spring 98 and extends radially through tube 13 to lock rod 9 in retracted position against the bias of spring 11. Actuation of the solenoid 7 retracts pin 10 to permit extension of rod 9 as shown in FIG. 4 to lift the iron body above a support surface under the action of spring 11. As shown in FIG. 6, a switch contact SW4 is controlled by a portion of plunger 10 of solenoid 7 and normally is in closed position to maintain circuit continuity to the heating coil 6. Switch contact SW2, of course, must be closed to energize the heater 6.
As shown in FIG. 4, when solenoid withdraws pin 10, rod 9 is extended to lift the iron. This occurs after a predetermined time delay after grip plunger 2 is released through operation of a time delay control circuit. In operation, the withdrawal of the operator's hand from grip 1 releases plunger 2 to reset switch 3. Switch contact SW2 is opened to open the circuit to the heating coil 6 and the switch contact SW1 is closed to energize the IC delay circuit shown in FIG. 6. The IC circuit generates a pluse supplied to the gate of an SCR to enable SCR to conduct within a predetermined period of time. When the SCR is conductive, the circuit to solenoid 7 is closed to pull pin 7 out of engagement with rod 9 to permit spring 11 to extend rod 9 as shown in FIG. 4. As a result, the iron body 14 is lifted off the support surface and the fabric. The movement of the pin 10 to retracted position also causes opening of switch contact SW4 to open the circuit to the solenoid 7 to permit pin 10 to quickly return toward the rod 9. The pin 10 then extends under action of spring 8 toward the tapered conical slope 93 of rod 9 disposed between locking group 92 and a stop surface 94 at the end area of rod 9 near the spring 11. The opening of contacts SW4 also opens the time delay circuit including the IC circuit. Thus, the iron of the present invention will not cause fire even if left in a horizontal position because power to the heating coil and control circuit are cut off.
When the operator desires to use the iron again, downward pressure applied to grip 1 causes rod 9 to retract within tube 13 against spring 11 so that locking pin 10 is cammed by the conical slope 93 of the rod 9 and locked in groove 92 to once again lock the rod 9 in retracted position in tube 13. In th meantime, switch contact SW4 has beem moved to the closed position to complete the circuit to the heater and the time delay circuit. By depressing plunger 2 while the operator's hand remains holding the grip 1, contacts SW2 and SW1 in the switch 3 again are respectively opened and closed to complete the circuit to the heating coil 6, so that the iron may be used for ironing while the time delay circuit is inactivated.
FIG. 5 shows the iron in upright supported position against the heel of the grip 1. The iron is preheated without using switch 3 by standing the iron on the heel of grip 1 to depress push-button 5 connected to switch contact SW3 and SW5. Contacts SW3 are normally open and contacts SW5 are normally closed when button 5 is extended. In such condition, switch 3 controls the circuits to the heater and the IC time delay circuit. When the iron is supported in an upright position with push-button 5 retracted or depressed, the positions of contacts SW3, SW5 are reversed or depressed, the positions of contacts SW3, SW5 are reversed so that the circuit to heater 6 is closed and the circuit to the time delay circuit is opened.
FIG. 6 shows the electronic control circuit for the present invention. A transformer T has two step-down coils on the secondary side in circuit with a full wave rectifier. The first secondary coil is connected to two diodes D1, D2 from where output of positive rectified voltage will be fed to the positive side of thyrister SCR which is in series with coil S of the solenoid 7 to complete a circuit with the negative side of the supply voltage. The gate of the SCR remains passie with SCR not in conduction and with solenoid 7 consituting part of the circuit loop. The second secondary coil is in series connection with two diodes D3, D4 from where output of positive rectified voltage will be fed to the IC by way of switch contacts SW1, SW5 to form a time delay circuit with resistors R1, R2 and capacitors C3 and C4. Capacitors C1, C2 are provided as filters. The reference symbol "S" in the figure represents the induction coil of the solenoid 7 while switch contact SW2 controls the heating coil 6 and SW1 controls power to the control circuit IC. The switch contacts SW3 are part of the preheating switch 5 for the heating coil and contacts SW5 are contacts in circuit with the IC time delay circuit.
To actuate the solenoid, the SCR must be set to conduction by having an incitation voltage carried in the form of a pulse signal released from the IC circuit and received at the gate thereof. Further reference may be had to FIGS. 3-5, in which it is seen that the control circuit receives power when the iron body is set upright to stand on its rear edge. The push-button switch 5 will be repressed due to the weight of the iron and contact SW3 is closed to bring the heating coil 6 into a heat-up condition. Since contact SW5 is interdependently associated with contact SW3, it is opened when buttom 5 is depressed to cut off the power to the time delay circuit IC. During ironing, the operator's hand must continue holding grip 1 so that the plunger 2 is depressed to actuate switch 3, whereupon the contact SW2 will be closed and the heater energized. The contact SW1 will be open to cut off power to the IC to deactivate same. Contact SW5 is closed (push-button extended) and SW1 is in series with SW5. SW1 remains open while ironing is carried out and control circuit IC remains inactive.
When the ironing operation is stopped or suspended following withdrawal of the operator's hand from the iron grip 1, contact SW2 of switch 3 is opened and contact SW1 is closed to energize the IC circuit. After a predetermined time delay, the IC generates a voltage pulse to the gate of SCR so that SCR is rendered conductive. Solenoid 7 will induce the pin 10 to withdraw from the locking groove 92 upon energization, resulting in uplifting of the iron body 14 by means of the main spring 11. The contact SW4 is opened by movement of pin 10, thereby cutting off the power to the control circuit IC, the heating coil 6 and the coil S of the solenoid 7. Locking pin spring 8 extends pin 10 to engage the tapered slope 93 of rod 9 and the stop surface 94, whereupon the iron body 14 is kicked off the surface of fabric upon which ironing is being carried out.
To resume operation after the iron body 14 has been moved up, iron body 14 is depressed by manipulating grip 1 to cause rod 9 to retract within tube 13 against compression spring 11. The pin 10 will cam along the conical slope 93 to reach groove 92 and once again engage same. In the meantime, the contact SW4 has been closed upon return of pin 10 and contact SW2 is also depressed by the grip plunger 2 to close the circuit to heater 6 and open the circuit including the IC time delay circuit.
The principles, preferred embodiments and modes of operation of the present invention have been described in the foregoing specification. The invention which is intended to be protected herein should not, however, be construed as limited to the particular forms described, as these are to be regarded as illustrative rather than restrictive. Variations and changes may be made by those skilled in the art without departing from the spirit of the invention. Accordingly, the foregoing detailed description should be considered exemplary in nature and not as limiting to the scope and spirits of the invention set forth in the appended claims.
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An electrical safety iron includes a safey circuit that automatically cuts off power if a pause of operation exceeds a prescribed time limit and lifts the main body of the iron from the surface being ironed so as to avoid damaging the texture of the fabric being ironed or causing a fire. An override preheat switch is provided to enable supply of power to the heater of the iron even if it is unattended, provided it is supported in the upright position. An electrical time delay circuit controls timing of the automatic power cutoff and lifting of the iron when it is unattended.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application claims the benefit of prior provisional application, U.S. Ser. No. 61/069,046, filed Mar. 12, 2008, and is a continuation of U.S. Ser. No. 12/830,391, filed Feb. 26, 2009, both of which are hereby incorporated by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention is directed to hydroswellable (or water-swellable) absorbable and non-absorbable aliphatic, segmented polyurethanes and polyurethane-ureas, which can undergo swelling when placed in the biological environment manifested through an at least 3 percent increase in volume by virtue of having a highly hydrophilic polyalkylene oxide as an inherent part of their segmented chain molecules. By varying the type and fraction of the different segments constituting the copolymers, their pharmaceutical and biomedical applications as non-absorbable and absorbable materials entail their use in carriers for the controlled release of bioactive agents, rheological modifiers of absorbable and non-absorbable cyanoacrylate tissue adhesives, synthetic cartilage-like materials, and scaffolds for tissue engineering cartilage tissues.
BACKGROUND OF THE INVENTION
[0003] Polyurethanes represent a main class of synthetic elastomers applied for long-term, medical implants as they present tunable chemical properties, excellent mechanical properties, good blood compatibility, and also can be designed to degrade in biological environments [A. Rechichi et al., J. Biomed. Mater. Res., 84-A, 847 (2008)]. More specifically, polyether-urethane (PEU) and polyether-urethane-urea (PEUU) elastomers have long been considered ideal for use in many implanted devices, in spite of occasionally cited drawbacks [M. A. Schubert et al., J. Biomed. Mater. Res., 35, 319 (1997); B. Ward et al., J. Biomed. Mater. Res., 77-A, 380 (2008)]. Of the cited drawbacks are those associated with (1) the generation of aromatic diamines, which are considered to be toxic upon degradation of segmented copolymers made using aromatic diisocyanates for interlinking; (2) chain degradation due to oxidation or radiation degradation of the polyether component of segmented copolymers, and particularly those which encounter frequent mechanical stresses in the biological environment; and (3) chemical degradation in chemically and mechanically hostile biological environments of the urethane links of segmented copolymers and particularly those comprising reactive aromatic urethane linkages.
[0004] Liquid solventless, complex polymeric compositions, which thermoset at ambient temperatures through additional polymerization of a two-component system, wherein the first component comprises amine or acrylate-terminated polyurethanes or polyurethane-ureas and the second component comprises di-or polyacrylates have been described in U.S. Pat. No. 4,742,147. However, the prior art is virtually silent on self-standing PEU and PEUU liquid solventless compositions for use in pharmaceutical formulations and/or medical devices. Similarly, the prior art on polyether-urethanes is practically silent on hydroswellable (or water-swellable) systems, in spite of the fact that it covered elastomeric, segmented, hydrophilic polyether-urethane-based, lubricious coating compositions based on aromatic diisocyanate and polyethylene glycol (U.S. Pat. No. 4,990,357)—it did not suggest a self-standing material for medical device applications.
[0005] Collective analysis of the prior art on PEU and PEUU as discussed above regarding the drawbacks of the disclosed systems, absence of self-standing liquid and hydroswellable copolymers, and recognition of the need for new materials exhibiting properties that cannot be met by those of the prior art, provided a strong incentive to explore the synthesis and evaluation of the PEU and PEUU systems subject of this invention, which are structurally tailored for their effective use in existing and new applications.
SUMMARY OF THE INVENTION
[0006] The present invention is directed to different types of hydroswellable (or water-swellable) polyurethanes and polyurethane-ureas.
[0007] A specific aspect of the invention describes a hydroswellable, segmented, aliphatic polyurethane comprising polyoxyalkylene chains, covalently linked to polyalkylene carbonate chains, which are interlinked with aliphatic urethane segments, the composition exhibiting an at least 3 percent increase in volume when placed in the biological environment, wherein the polyoxyalkylene glycol chains comprise at least one type of oxyalkylene sequences selected from the group represented by oxyethylene, oxypropylene, oxytrimethylene, and oxytetramethylene repeat units and the alkylene carbonate chains are trimethylene carbonate sequences, and wherein the urethane segments are derived from at least one diisocyanate selected from the group represented by tetramethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, lysine-derived diisocyanate, and cyclohexane bis-(methylene isocyanate). Meanwhile, the polyurethane is made by reacting a liquid polyoxylene alkylene glycol comprising oxyethylene or a combination of oxyethylene and oxypropylene sequences that are end-grafted with trimethylene carbonate wherein the resulting product is interlinked with 1,6-hexane diisocyanate, and wherein the liquid polyalkylene glycol is a polyethylene glycol having, preferably, a molecular weight of about 400-500 Da. From a pharmaceutical application perspective, the polyurethanes can be used as vehicles for a controlled release formulation of at least one bioactive agent selected from the group of agents known to exhibit anti-inflammatory, anesthetic, cell growth promoting, antimicrobial, antiviral, and antineoplastic activities. In a specific pharmaceutical application, the controlled release formulation comprises at least one antimicrobial agent after treating periodontitis or bone infection selected from the group represented by doxycycline, gentamicin, vancomycin, tobramycin, clindamycin, and mitomycin and the periodontal formulation may include absorbable microparticles made of acid-terminated glycolide-based polyester and a liquid excipient such as a liquid polyethylene glycol and an alkylated or acylated derivative thereof. In a second group of pharmaceutical applications, the controlled release formulation comprises a liquid polyethylene glycol or an alkylated or acylated derivative thereof as an excipient and at least one bioactive agent selected from the group represented by paclitaxel, carboplatin, miconazole, leflunamide, ciprofloxacin, and a recombinant protein for treating breast or ovarian cancer in humans or animals. Additionally, for tissue repair applications, the polyurethane can be admixed with one or more cyanoacrylate monomer for use as a rheological modifier of tissue adhesives, wherein the one or more cyanoacrylate monomer is part of an absorbable or non-absorbable tissue adhesive formulation comprising stabilizers against premature polymerization, free radically and anionically, and at least one monomer selected from the group represented by ethyl-, butyl-, isobutyl-, methoxypropyl-, methoxyethyl-, and methoxybutyl cyanoacrylate.
[0008] Another specific aspect of the present invention deals with a hydroswellable, segmented, aliphatic polyurethane-urea comprising polyoxyalkylene chains covalently interlinked with polyalkylene urethane segments, which are further interlinked with aliphatic urea chain segments, the composition exhibiting at least 5 percent increase in volume when placed in the biological environment, wherein the polyalkylene glycol chains comprise at least one type of oxyalkylene sequences selected from the group represented by oxyethylene, oxypropylene, oxytrimethylene, and oxytetramethylene repeat units and the urethane segments are derived from at least one diisocyanate selected from the group represented by hexamethylene diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 1,4 cyclohexane diisocyanate, lysine-derived diisocyanate, and cyclohexane bis(methylene isocyanate) and wherein the resulting polyoxyalkylene urethane molecules having at least one isocyanate terminal group are chain-extended with an alkylene diamine selected from the group represented by ethylene-, trimethylene, tetramethylene-, hexamethylene-, and octamethylene-diamine, thus forming polyetherurethane-urea segmented chains.
[0009] A clinically important aspect of the invention deals with a hydroswellable, segmented, aliphatic polyurethane-urea comprising polyoxyalkylene chains covalently interlinked with polyalkylene urethane segments, which are further interlinked with aliphatic urea chain segments, the composition exhibiting at least 5 percent increase in volume when placed in the biological environment, wherein the polyurethane-urea (1) can be chemically crosslinked, wherein the crosslinking is achieved using an alkylene diisocyanate; (2) can exhibit microporosity with a practically continuous cellular structure; (3) can comprise at least one covalently bonded aromatic group to stabilize the chain against radiation and oxidation degradation; and/or (4) can be used as an artificial cartilage for restoring the function of diseased or defective articulating joints in humans and animals.
[0010] An important aspect of this invention deals with a hydroswellable, segmented, aliphatic polyurethane comprising polyoxyalkylene chains covalently linked to polyester or polyester-carbonate chain segments, interlinked with aliphatic urethane segments, the composition exhibiting at least 5 percent increase in volume when placed in the biological environment, wherein the polyester or polyester-carbonate chain segments are derived from at least one cyclic monomer selected from the group represented by ε-caprolactone, trimethylene carbonate, p-dioxanone, 1,5-dioxepan-2-one, l-lactide, dl-lactide, glycolide, and a morpholinedione. Meanwhile, the polyurethane can exhibit microporosity with practically continuous cellular structure for use as an absorbable scaffold or part thereof for cartilage tissue engineering, with or without the aid of a cell growth promoting agent therein.
[0011] For prolonged effective device performance, the present invention is directed to a hydroswellable, segmented, aliphatic polyurethane-urea comprising a combination of linear functionalized polysiloxane and polyoxyalkylene chains interlinked with polyalkylene urethane segments, which are further interlinked with aliphatic urea chain segments, the composition exhibiting at least 5 percent increase in volume when placed in the biological environment, wherein the polyoxyalkylene chain comprises at least one type of oxyalkylene sequences selected from the group represented by oxyethylene, oxypropylene, oxytrimethylene, and oxytetramethylene repeat units and the functionalized polysiloxane is derived from bis-hydroxyalkyl-terminated polysiloxane comprising at least dimethoxysiloxane internal sequences and two hydroxyalkyl or aminoalkyl terminals and further wherein the urethane segments are derived from at least one diisocyanate selected from the group represented by hexamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 1,4 cyclohexane diisocyanate, lysine-derived diisocyanate, and cyclohexane bis(methylene isocyanate) and wherein the resulting polyoxyalkylene urethane molecules having at least one isocyanate terminal group are further chain-extended with an alkylene diamine selected from the group represented by ethylene-, trimethylene, tetramethylene-, hexamethylene- and octamethylene-diamine, thus forming polyetherurethane-urea segmented chains, wherein the polyurethane-urea (1) can be chemically crosslinked wherein the crosslinking is achieved using an alkylene diisocyanate; (2) can exhibit microporosity with a practically continuous cellular structure; (3) can comprise at least one covalently bonded aromatic group to stabilize the chain against radiation and oxidation degradation; and/or (4) can be used as an artificial cartilage for restoring the function of diseased or defective articulating joints in humans and animals.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0012] The present invention is generally directed to the tailored synthesis of the following families of hydroswellable polymers. The term “hydroswellable” is intended to indicate that the polymers swell and increase in volume in the presence of water.
[0013] (1) Relatively slow-absorbing, segmented polyether-carbonate-urethanes (PECU) as vehicles for the controlled release of bioactive agents including those known to exhibit or unexpectedly exhibit antimicrobial, microbicidal, antineoplastic, and antiviral activities wherein the typical PECUs (a) exhibit <20 percent or no solubility in water; (b) are made to be liquids at about 50° C.; (c) have a weight average molecular weight exceeding 10 kDa; (d) swell in an aqueous environment leading to an increase of volume of at least 3 percent; and (e) are miscible in water-soluble, low viscosity liquid excipients, such as polyethylene glycol 400, to facilitate their use as injectable formulations that undergo gel-formation when introduced to aqueous biological sites—the ratio of the PECU to the excipient can be modulated in concert with the active agent solubility, its intended release site, and preferred release rate.
[0014] (2) The PECUs of Item 1 as rheology modifiers of cyanoacrylate-based tissue adhesive formulations wherein (a) the PECU is used to increase the viscosity of the uncured tissue adhesive; (b) render the cured tissue adhesive more compliant and able to conform with the biological site—this is achieved by decreasing the cured adhesive modulus due to the presence of the low modulus PECU at concentrations of at least one weight percent; (c) the cyanoacrylate tissue adhesive comprises at least one monomer selected from the group represented by ethyl-, n-butyl-, isobutyl-, methoxypropyl-, ethoxypropyl-, methoxybutyl-, and octyl-cyanoacrylate; and (d) the cyanoacrylate tissue adhesive contains at least one stabilizer to prevent premature polymerization by an anionic and free radical mechanism—typical examples of these are pyrophosphoric acid and butylated hydroxyl anisole for stabilization against anionic and free radical polymerization, respectively.
[0015] (3) Relatively fast-absorbing, segmented aliphatic polyether-ester urethanes (PEEU) and polyether-carbonate-ester urethanes (PECEU) as vehicles for the controlled release of bioactive agents including those known to exhibit or unexpectedly exhibit antimicrobial, microbicidal, antiviral, and antineoplastic activities wherein the typical PEEUs and PECEUs (a) exhibit limited (<20 percent) or no solubility in water; (b) are made to be liquids at about 50° C.; (c) have a weight average molecular weight exceeding 10 kDa; (d) swell in an aqueous environment leading to an increase of volume of at least 3 percent; and (e) are miscible in water-soluble, low viscosity liquid excipients, such as polyethylene glycol 400 and an alkylated or acylated derivative thereof, to facilitate their use as injectable formulations that undergo gel-formation when introduced to aqueous biological sites—the ratio of the PECU to the excipient can be modulated in concert with the active agent solubility, its intended release site, and preferred release rate.
[0016] (4) The PEEUs and PECEUs of Item 3 as rheology modifiers of absorbable cyanoacrylate-based tissue adhesive formulations wherein (a) the PEEU or PECEU is used to increase the viscosity of the uncured tissue adhesive; (b) render the cured tissue adhesive more compliant and able to conform with the biological site—this is achieved by decreasing the cured adhesive modulus due to the presence of the low modulus PEEU or PECEU at concentrations of at least one weight percent; (c) the cyanoacrylate tissue adhesive comprises an alkoxyalkyl cyanoacrylate, such as methoxypropyl cyanoacrylate or a mixture of an alkoxyalkyl cyanoacrylate and an alkyl cyanoacrylate, such as ethyl cyanoacrylate; and (d) the cyanoacrylate tissue adhesive contains at least one stabilizer to prevent premature polymerization by an anionic and free radical mechanism—typical examples of these are pyrophosphoric acid and butylated hydroxyl anisole for stabilization against anionic and free radical polymerization, respectively.
[0017] (5) Essentially biostable, non-absorbable, segmented, aliphatic polyether urethane-ureas (PEUU) as flexible, solid, linear or chemically crosslinked polymers for use primarily as cartilage-like materials, which undergo swelling and deswelling upon cyclic application of compressive force for prolonged periods, while practically maintaining their initial properties, wherein the typical PEUUs (a) exhibit limited (<5 percent) or no solubility in water; (b) can be fabricated into films, sheets or caps for articulating bones in humans or animals with essentially no display of first order thermal transitions and exhibiting ultimate elongation exceeding 200 percent, reversible elongation of >10 percent and an at least 5 percent increase in volume when immersed in water for less than two hours; (c) have a molecular weight corresponding to an inherent viscosity of more than unity using hexafluoro-isopropyl alcohol (HFIP) as a solvent when present as linear molecular chains,; and (d) can be fabricated into different desirable forms or geometries by solution casting.
[0018] (6) Highly biostable, non-absorbable, segmented, aliphatic PEUU as in Item 5 comprising a polysiloxane (e.g., poly dimethyl siloxane segment) to improve its oxidation stability in the biological environment.
[0019] (7) Highly biostable, non-absorbable. segmented, aliphatic PEUU as in Item 5 comprising a covalently bonded chemical entity capable of minimizing or eliminating radiation during radiation sterilization, and oxidative degradation when placed in the biological environment. These radiation and oxidation stabilizers can be in the form of polymerizable (as in diols) derivatives of hydroxyl aromatic compounds or low molecular polymers comprising oxy-aromatic groups and hydroxyl end-groups. Such simple or polymeric diols can be mixed with the polyether diol prior to end-grafting with other monomers and interlinking with diisocyanate.
[0020] (8) Absorbable, segmented, aliphatic polyether-ester urethane (APEEU) and polyether-ester-carbonate urethane (APEECU) as scaffolds for cartilage tissue engineering wherein the typical APEEUs and APEECUs (a) comprise polyoxyalkylene chains (such as those derived from polyethylene glycol and block or random copolymers of ethylene oxide and propylene oxide) covalently linked to polyester or polyester-carbonate segments (derived from at least one monomer selected from the group represented by trimethylene carbonate, ε-caprolactone, lactide, glycolide, p-dioxanone, 1,5-dioxepan-2-one, and a morpholinedione) and interlinked with aliphatic urethane segments derived from 1,6 hexamethylene-, 1-4 cyclohexane-, cyclohexane-bis-methylene-, 1,8 octamethylene- or lysine-derived diisocyanate; (b) display at least 5 percent increase in volume due to swelling, when placed in the biological environment; (c) have a microporous structure with average pore size ranging between about 20 and 400 micron and practically continuous cell structure; and (d) are suitable for use as an absorbable scaffold for cartilage tissue engineering wherein the scaffold may contain at least one bioactive agent which may include at least one cell growth promoter.
[0021] From a clinical perspective, compositions and formulations or devices thereof subject of the present invention can be used in a broad-range of applications including (1) injectable gel-forming liquid formulations for the controlled delivery of bioactive agents for treating periodontitis, nail infection, bone infection, a variety of bacterial and fungal infections, and different forms of cancers; (2) in situ-forming, extrudable luminal liner for the controlled drug delivery at the luminal wall of vaginal canals and blood vessels; (3) a rheology modifier for essentially non-absorbable and absorbable cyanoacrylate-based tissue adhesive formulations; (4) cartilage-like covers to protect defective or diseased articulating joints; and (5) an absorbable scaffold for cartilage and soft tissue engineering.
[0022] Further illustrations of the present invention are provided by the following examples:
EXAMPLE 1
Synthesis and Characterization of a Typical Polyether-carbonate-urethane, P-1
[0023] For an initial charge, poly(ethylene glycol) (M n =400 Da) (0.15 moles) and tin(II) 2-ethyl hexanoate (3.53×10 −4 moles) were added to a 500 mL, 3-neck, round-bottom flask equipped with a PTFE coated magnetic stir bar. The contents were heated to 70° C. and allowed to stir for 10 minutes. For a second charge, trimethylene carbonate (0.882 moles) was added and the contents were heated to 135° C. Conditions were maintained until practically complete monomer conversion was achieved. The magnetic stir bar was removed and replaced by a stainless steel mechanical stirrer. The polymer was cooled to room temperature. For a third charge, 1,6-diisocyanatohexane (0.12 moles) was added and the contents were stirred until complete mixing was achieved. The contents were stirred and heated to 100° C. Conditions were maintained for 1.25 hours. The polymer was allowed to cool to room temperature and then dissolved in an equal part of tetrahydrofuran. The polymer solution was treated with 5 mL of 2-propanol at 55° C. then precipitated in cold water. The purified polymer was isolated and dried to a constant weight at 55° C. on a rotary evaporator. The purified polymer was characterized for molecular weight by GPC using tetrahydrofuran as the mobile phase which resulted in an M n , M w , M p , and PDI of 11 kDa, 19 kDa, 18 kDa, and 1.7 respectively. Identity and composition were confirmed by FT-IR and NMR, respectively.
EXAMPLE 2
Synthesis and Characterization of Liquid Polyether-ester-urethane: General Method
[0024] For an initial charge, poly(ethylene glycol) (M n =400 Da) and tin(II) 2-ethyl hexanoate were added to a 500 mL, 3-neck, round-bottom flask equipped with a PTFE coated magnetic stir bar. The contents were heated to 70° C. and allowed to stir for 10 minutes. For a second charge, dl-lactide and glycolide were added and the contents were heated to 135° C. Conditions were maintained until practically complete monomer conversion was achieved. The magnetic stir bar was removed and replaced with a stainless steel mechanical stirrer. The polymer was cooled to room temperature. For a third charge, 1,6-diisocyanatohexane was added and the contents were stirred until complete mixing was achieved. The contents were stirred and heated to 100° C. Conditions were maintained for 1.25 hours. The polymer was allowed to cool to room temperature and then dissolved in an equal part of tetrahydrofuran. The polymer solution was treated with 5 mL of 2-propanol at 55° C. then precipitated in cold water. The purified polymer was dried to a constant weight at 55° C. on a rotary evaporator. The purified polymer was characterized for molecular weight by GPC using tetrahydrofuran as the mobile phase. Identity and composition were confirmed by FT-IR and NMR, respectively.
EXAMPLE 3
Synthesis and Characterization of Typical Polyether-ester-urethanes Using the General Method of Example 2, P-2, P-3, and P-4
[0025] Polyether-ester-urethanes P-2, P-3, and P-4 were prepared using the method of Example 2 with 0.15, 2.225, 0.15 moles of polyethylene glycol (M n =400 Da), 2.60×10 −4 , 3.18×10 −4 , 2.60×10 −4 moles of tin(II) 2-ethyl hexanoate, 0.52, 0.64, 0.52 moles of dl-lactide, 0.13, 0.16, 0.13 moles of glycolide, and 0.18, 0.18, 0.12 moles of 1,6-diisocyanatohexane, respectively. Polymers P-2, P-3, and P-4 were characterized for molecular weight by GPC using tetrahydrofuran as the mobile phase which resulted in M n of 11, 9, and 9 kDa, M w of 20, 14, and 15 kDa, Mp of 20, 12, 14, kDa, and PDI of 1.9, 1.6, and 1.6, respectively. Identity and composition were confirmed by FT-IR and NMR, respectively.
EXAMPLE 4
Synthesis and Characterization of Typical Polyether-ester-urethanes using the General Method of Example 2, P-5 to P-8
[0026] Polyether-ester-urethanes P-5, P-6, P-7 and P-8 were prepared using the method of Example 2 with 0.15, 0.22, 0.22, 0.22 moles of polyethylene glycol (M n =400 Da), 3.53×10 −4 , 4.17×10 −4 , 4.22×10 −4 , 4.12×10 −4 moles of tin(II) 2-ethyl hexanoate, 0.88, 0.94, 1.08, and 0.80 moles of trimethylene carbonate (TMC), 0.00, 0.31, 0.19, and 0.43 moles of glycolide, and 0.12, 0.18, 0.18, and 0.18 moles of 1,6-diisocyanatohexane, respectively. Polymers P-5, P-6, P-7 and P-8 were characterized for molecular weight by GPC using tetrahydrofuran as the mobile phase which resulted in M n of 11, 10, 10, and 9 kDa, M w of 19, 14, 16, and 14 kDa, Mp of 18, 13, 15, and 14 kDa, and PDI of 1.7, 1.4, 1.6 and 1.5, respectively. Identity and composition were confirmed by FT-IR and NMR, respectively.
EXAMPLE 5
Synthesis and Characterization of Acetylated Polyethylene Glycol-400 (PG-4A) for Use as a Diluent Liquid Excipient of P-2 to P-8
[0027] Predried polyethylene glycol having a molecular weight of about 400 Da (25.6 g) was mixed in a round-bottom flask (equipped for magnetic stirring and refluxing) under dry nitrogen atmosphere with purified acetic anhydride (22.2 g). The mixture was stirred for 1 hour at 40° C. and then at 100° C. for 3 hours. At the conclusion of the reaction, the contents of the flask were heated under reduced pressure to remove the acetic acid reaction by-product and excess acetic anhydride. The acetylated product (PG-4A) was characterized for identity by infrared spectroscopy and molecular weight by gel permeation chromatography (GPC).
EXAMPLE 6
Synthesis, Characterization, and Testing of a Typical Film-forming Polyether-urethane-urea, PEUU-I
[0028] Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (M n =14,600 Da, 82.5 wt % poly(ethylene glycol) (1.64×10 −3 moles) and poly(tetramethylene glycol) (M n =2,900 Da) (1.93×10 −2 moles) were added to a 500 mL glass resin kettle equipped for mechanical stirring and vacuum. The contents were dried at 140° C. under reduced pressure for 3 hours and then cooled to room temperature. N,N-Dimethylacetamide (190 mL) was added and the contents were heated to 60° C. and stirred until a homogeneous solution was obtained. The contents were cooled to room temperature and 1,6-diisocyanatohexane (3.14×10 −2 moles) was added. The contents were stirred until a homogeneous solution was obtained. Tin(II) 2-ethyl hexanoate (3.53×10 −4 moles) in the form of a 0.2M solution in 1,4-dioxane was added. The contents were stirred until a homogeneous solution was obtained and then heated to 100° C. under stirring conditions. Conditions were maintained for 2 hours. The contents were cooled to room temperature. Ethylene diamine (1.05×10 −2 moles) was added in the form of a 1.16M solution in N,N-dimethylacetamide under stirring conditions. Upon gelation, the stirrer was stopped and conditions were maintained for 24 hours. The polymer was purified by subsequent extractions with water and acetone then dried to a constant weight at 45° C. under reduce pressure. The purified polymer was characterized for molecular weight by inherent viscosity in hexafluoroisopropanol which resulted in an inherent viscosity of 5.71 dL/g. Identity was confirmed by FT-IR.
EXAMPLE 7
Preparation and Properties of n-Butyl Cyanoacrylate-based Tissue Adhesive Formulation Using P-5 from Example 4 as a Rheology Modifier
[0029] This entailed mixing and characterizing the different monomer combinations and using a selected mixture to prepare a typical adhesive formulation
[0030] A pure methoxypropyl cyanoacrylate (MPC) and pure n-butyl cyanoacrylate (BC) monomers and combination thereof were characterized for their rheological properties, measured in terms of their comparative viscosity as listed Table I. Ratios of 90/10, 50/50, 20/80, and 10/90 (by weight) of MPC to butyl cyanoacrylate were mixed. Monomers were weighed in a centrifuge tube and placed on a shaker for 15 minutes. The rheological data of the resulting compositions are summarized in described in Table I.
[0000]
TABLE I
Cyanoacrylate Monomer Compositions
and Their Rheological Data a
Monomer Ratios
Monomer Composition
Comparative Viscosity (s)
100
BC
3.30 ± 0.06
10:90
MPC:BC
3.42 ± 0.06
20:80
MPC:BC
3.55 ± 0.10
50:50
MPC:BC
4.23 ± 0.14
90:10
MPC:BC
5.16 ± 0.17
100
MPC
6.15 ± 0.36
a Measured in terms of time (in seconds) to collect 0.3 mL of liquid adhesive, transferring vertically by gravity through an 18-guage, 1.5 in. long syringe needle.
[0031] A selected formulation was prepared by dissolving 3% (by weight) of P1 in a 20/80 (by weight) mixture of methoxypropyl cyanoacrylate and butyl cyanoacrylate containing 500 ppm of butylated hydroxyanisole and 3.3 ppm of pyrophosphoric acid stabilizers against free radical and anionic polymerization, respectively. More specifically, this entailed the following steps: (1) the P1 polymer was added to a flask and dried at 80° C. for 3 hours; (2) the cyanoacrylate monomers and the stabilizers were added; and (3) the resulting mixture was stirred at 80° C. until it became homogenous. The resulting formulation exhibited a comparative adhesive viscosity of 12.63 s and an adhesive joint strength of 28.35 N (using a fabric peel test).
EXAMPLE 8
Preparation and Properties of Absorbable Cyanoacrylate Tissue Adhesive Formulation Using P-6 of Example 4 as a Rheology Modifier
[0032] The adhesive formulation was prepared by dissolving 5% (by weight) of P-6 in a 90/10 (by weight) mixture of methoxypropyl cyanoacrylate and ethyl cyanoacrylate containing 500 ppm of butylated hydroxyanisole and 3.3 ppm of pyrophosphoric acid as stabilizers against free radical and anionic polymerization, respectively. More specifically, this entailed the following steps: (1) the P3 polymer was added to a flask and dried at 80° C. for 3 hours; (2) the cyanoacrylate monomers and stabilizers were added; and (3) the resulting mixture was stirred at 80° C. until it became homogenous. The resulting formulation exhibited a comparative adhesive viscosity of 6.74 s and an adhesive joint strength of 34.96 N (using a fabric peel test).
EXAMPLE 9
Preparation of a Doxycycline Hyclate Controlled Release Formulation Using P-2 From Example 3 and Determination of the Drug Release Profile
[0033] This entailed a three-step process, namely, mixing P-2 (from Example 3) with a diluent liquid excipient (from Example 5), acetylated polyethylene glycol-400 (PG-4A), preparation of an active formulation, and monitoring the drug release profile.
[0034] Mixing P-2 with PG-4—For this, P-2 (3.2691 g) was placed in a glass vial and PG-4A (1.7603 g) was added. The contents of the vial were heated to 50° C. and mechanically mixed until a homogenous mixture developed. The final mixture was 65 weight percent P-2 with the remainder consisting of PG-4A.
[0035] Preparation of Active Formulation—To prepare a liquid vehicle, an aliquot of 2.0237 g of the P-2/PG-4A mixture was transferred to a glass vial, and doxycycline hyclate (434 mg) was added to the vial. Microparticles of acid-terminated polyglycolide (433 mg) were added to the contents of the vials. This was followed by heating to 50° C. and mixing mechanically to obtain a homogenous mixture. The resulting mixture was 70 weight percent liquid vehicle, 15 percent polyglycolide microparticles, and 15 percent doxycycline hyclate.
[0036] Release Study—The active formulation (1.0230 g) was placed in a small glass vial and heated to 50° C. to flow into bottom of vial and create a uniform coating and then was allowed to cool to room temperature. Phosphate buffer (10 mL, pH 7.2) was placed into the glass vial, which was transferred to a 37° C. incubator. The buffered solution (with released drug) was withdrawn at predetermined time points and replaced with 10 mL of fresh buffer. Aliquots of the release buffer were assayed by reverse phase HPLC, using a Waters Chromatography System with a C18 column, a gradient of 15-30% acetonitrile over 10 minutes, and detection at 350 nm; the amount of doxycycline released over time was determined. The HPCL data indicated a cumulative release at 23, 94, and 163 hours of 16%, 31%, and 45%, respectively.
[0037] Although the present invention has been described in connection with the preferred embodiments, it is to be understood that modifications and variations may be utilized without departing from the principles and scope of the invention, as those skilled in the art will readily understand. Accordingly, such modifications may be practiced within the scope of the following claims. Moreover, Applicant hereby discloses all subranges of all ranges disclosed herein. These subranges are also useful in carrying out the present invention.
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Hydroswellable, absorbable and non-absorbable, aliphatic, segmented polyurethanes and polyurethane-urea capable of swelling in the biological environment with associated increase in volume of at least 3 percent have more than one type of segments, including those derived from polyethylene glycol and the molecular chains are structurally tailored to allow the use of corresponding formulations and medical devices as carriers for bioactive agents, rheological modifiers of cyanoacrylate-based tissue adhesives, as protective devices for repairing defective or diseased components of articulating joints and their cartilage, and scaffolds for cartilage tissue engineering.
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FIELD OF THE INVENTION
The present invention relates to a convected-air cabinet
BACKGROUND OF THE INVENTION
In Australian Patent Number 674764 in the name of the present applicant there is described and claimed a Pizza and Pasta Drive-Thru Facility. It relates to a facility for preparing and storing pizza and pasta in a fresh condition for a relatively long period of time.
An important component of this facility is a means for storing the cooked food and maintaining it within a predetermined heat and moisture range. This enables the food to be prepared ahead of time and stored until purchased by a customer.
It is known that in the delivery of fast food, the food for consumption is prepared in advance of the customer's order such that it is available to them immediately. It is known that some food holding cabinets contain heating elements or heated shelves which continue to cook the food and its packaging container whilst it is being stored, rendering it unfit for consumption after some minutes. It is also known to use moisture and heat within the holding cabinets to keep food for longer periods but it is found that opening these cabinets to insert and/or remove food items causes a large degree of temperature and related humidity variation, leading to extended periods where the cabinet is not at its desired temperature and/or humidity level.
The present invention attempts to overcome at least in part the aforementioned disadvantages of previous hot food holding cabinets.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention there is provided a convected-air cabinet characterized by comprising a front side provided with food access means, an opposed rear side provided with food access means, a base, a roof and spaced side walls interconnecting the front and rear sides, a plurality of regions within the cabinet for storage of food, wherein a first fan is mounted adjacent the base and is arranged beneath a laterally extending cover which extends from the front to the rear side but is spaced from each side, a second fan is mounted adjacent the roof and a laterally extending partition containing an aperture is mounted below the second fan, the laterally extending partition being spaced from the front and rear sides, such that air directed around the first laterally extending cover by the first fan is conveyed within the cabinet to the aperture in the second laterally extending cover and is then directed laterally by the second fan to form air curtains extending downwardly across the front and rear sides.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a rear isometric view of a convected-air cabinet in accordance with the present invention;
FIG. 2 is a front elevation of the convected-air cabinet of FIG. 1 ;
FIG. 3 is a schematic transverse sectional view of part of the convected-air cabinet of FIG. 1 ;
FIG. 4 is a schematic longitudinal sectional view of part of the convected-air cabinet of FIG. 1 ;
DESCRIPTION OF THE INVENTION
In FIGS. 1 and 2 there is shown a convected-air cabinet 10 comprising an outer body 12 having mounted thereto a food preparation shelf 14 .
The body 12 has a rear side 16 (see FIG. 1 ) and a front side 18 (see FIG. 2 ). The rear side 16 is provided with a plurality of doors 20 in a central portion thereof.
The doors 20 are hingedly mounted by means of respective pairs of upper hinges 22 and are provided with respective handles 24 to enable the doors 20 to be'opened and closed as required. The hinges may be of a soft close or self-closing type.
As will be described, a respective food warming region is disposed behind each door 20 .
The front side 18 is provided with a plurality of doors 26 . The doors 26 are hingedly mounted on respective pairs of side hinges 28 . Further, the doors 26 are provided with respective handles 30 to enable them to be opened and closed as required.
Also, the cabinet 10 further comprises a pasta warming facility 32 to one side thereof. The pasta warming facility 32 has a single rear door 34 (see FIG. 1 ) and a single front door 36 (see FIG. 2 ). The rear door 34 is mounted on a pair of side hinges 38 and may be opened and closed by means of a handle 40 as required. Similarly, the front door 36 is mounted on a pair of side hinges 42 and may be opened and closed as required by mean of a handle 44 . The pasta warming facility 32 is optional depending on the user's menu.
At the end thereof, remote from the pasta warming facility, the cabinet 10 has a storage facility 46 for pizza boxes and the like. The storage facility 46 is also optional and is primarily suited to a mobile kiosk facility.
The storage facility 46 may be provided with elongate members 48 on sides thereof to cover a portion of the front and back of the storage facility 46 . This is to ensure that a single stored item, such as a pizza box, may be removed at a time.
In FIG. 3 , there is shown in cross section a pair of food warming regions or compartments 50 in side by side relationship forming part of the apparatus of FIGS. 1 and 2 .
As can be seen in FIG. 3 , each compartment 50 has side walls 52 , a base 54 and a roof 56 . As shown on the left each compartment 50 contains a plurality of shelves 58 which are air permeable. For example the shelves 58 may be formed of metallic mesh. The shelves 58 are arranged to support items of food. Further, as shown on the left, each compartment 50 contains a basin 60 which, in use, contains water.
Further, a respective fan 62 is mounted to the base 54 at each compartment 50 . The fans 62 have drive shafts 64 arranged for axial rotation and a fan blade 66 above the base 54 . Each drive shaft 64 extends through the base 54 for operational connection to the fan blade 66 .
Further, electrical heating elements 68 are disposed on each side of each fan blade 66 .
Each food warming compartment 50 may contain a thermometer, a humidity probe, and a thermostat, so that temperature and humidity may be controlled at desired levels.
A cover 70 is mounted above the fan blade 66 to retain heat from the elements 68 in the region of the fan blade 66 . Further the cover 70 contains an aperture 72 to allow the ingress of air to the fan blade 66 . As shown, air is drawn in as indicated by arrows 74 .
Further, heated air is expelled by the fan blade 66 around the periphery of the cover 70 into the chamber 50 as indicated by arrows 76 .
As can be seen in FIG. 4 , each compartment 50 has a further fan 80 mounted at the top thereof. The fan 80 has an axially rotatable drive shaft 82 extending through the roof 56 . The shaft 82 is connected to a fan blade 84 .
Further, a partition 86 is mounted below the fan blade 84 . The partition 86 is spaced from the roof 56 and has a central aperture 88 therein adjacent the fan blade 64 . Further, the partition 86 extends laterally away from the fan blade 84 to positions close to the front side 18 and the rear side 16 of the cabinet 10 . In use, heated air from the compartment 50 is drawn by the fan blade 84 through the aperture 88 as indicated by arrows 89 and then blown laterally as shown by arrows 90 along the roof 56 to the end of the partition 86 adjacent the front side 18 and the rear side 16 . The partition 86 has downturned peripheral flanges 92 adjacent the sides 18 and 16 and upturned peripheral flanges 94 adjacent the side walls 52 .
The air then is directed downwardly along the front and rear sides 18 and 16 . In this way the air from the fan blade 84 produces an air curtain adjacent the doors 20 and 26 . Thus when the doors are opened as described hereinbefore to place food on the shelves or remove food therefrom the overall internal temperature and humidity of the compartment 50 is maintained close to the desired levels so as to reduce food spoilage.
Further, it is noted that the presence of the basins 60 , with water therein, ensures that the heated air distributed into the compartments 50 have a substantial moisture content. This is important as it removes any tendency of the stored food to dry out. Further, the heating elements 68 are preferably arranged such that whilst the air is heated it is not heated to a temperature sufficient to cause further cooking of the stored food.
The cabinet of the present invention is particularly intended for use in the hospitality industry, fast food outlets, mobile kiosks, transportable kitchens and truck semi-trailer applications.
As shown, the cabinet of the present invention may be made to have a large size with a number of compartments 50 so as to be able to supply customer needs continuously even at peak sales periods.
The cabinet of the present invention is particularly intended for storage of cooked pizza but it is applicable to storage of foods such as pasta, as described above.
Modifications and variations as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.
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A convected-air cabinet ( 10 ) for storage of food has fans ( 62, 84 ) for directing air from a lower part of the apparatus to an upper part. In particular there is an upper fan ( 84 ) mounted above an apertured partition ( 86 ) so that air entering through an aperture ( 88 ) in this partition ( 86 ) is directed laterally and then downwardly to provide air curtains adjacent food access means ( 20 ) at a front ( 16 ) and rear ( 18 ) of the cabinet.
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CROSS REFERENCE TO PRIOR APPLICATIONS
[0001] This application is a continuation of International Patent Application No. PCT/EP2010/061569, filed on Aug. 10, 2010, which claims benefit to German Patent Application Nos. 10 2009 037 052.8, filed on Aug. 13, 2009 and 10 2009 048 265.2, filed on Oct. 5, 2009. The entire disclosure of each of these applications is incorporated by reference herein.
FIELD
[0002] The present invention relates to the field of rotating electrical machines.
BACKGROUND
[0003] In the case of rotating electrical machines having slip-rings, for example a polyphase asynchronous motor in the form of a slip-ring rotor, currents are transmitted by means of appropriate brushes via the slip-rings which rotate with the shaft. One example of a rotating electrical machine such as this is illustrated, partially, in FIG. 1 . The rotating electrical machine 10 illustrated there, with its machine axis 17 , comprises a rotor, which can rotate about the machine axis 17 , with a central body 11 which merges at the end into a shaft 16 . A rotor laminated body 12 is seated on the central body 11 and a rotor winding 13 is accommodated in it, which rotor winding 13 has a rotor end winding 13 ′ at the end. The rotor 11 , 12 , 13 is concentrically surrounded by a stator laminated body 15 , in which a stator winding with a corresponding stator end winding 15 ′ is accommodated. A plurality of (four) slip-rings 14 are arranged on the outside of the shaft 16 and are used to transmit current between the rotor and the outside world. In the case of the machine illustrated in FIG. 1 , the power loss must be dissipated by means of specific cooling devices.
[0004] When machines of this type are highly loaded, particular attention must be paid to cooling in the area of the slip-rings. Because of the high electric and mechanical (friction) load on the brushes and the slip-rings 14 , an increased temperature development occurs in this area. Since the brushes react by increased wear to any discrepancy from the optimum operating temperature, and can be completely destroyed above a critical temperature, appropriate cooling must be provided for these components.
[0005] As is shown in FIG. 2 , the conventional design of the slip-ring area envisages a continuous shaft 16 on which the slip-rings 14 are mounted. With this design, the slip-rings 14 can be cooled only to a highly restricted extent. The cooling air (or some other cooling medium) would have to flow onto the slip-rings 14 from the outside. However, this is difficult because the slip-rings 14 rotate. Cooling from the interior, with the air flowing radially outwards from the interior of the shaft 16 , is impossible because of the closed shaft 16 . On the other hand, it is problematic for mechanical strength reasons to provide the shaft 16 with an appropriately large number of openings.
[0006] EP-A1-0 052 385 describes a slip-ring arrangement for electrical machines, in which the slip-rings are provided with axial cooling gas holes, which are cut in the form of grooves or slots in the slip-ring surface. Cooling gas passes radially outwards via the grooves or slots into the cooling gas holes, with heat being absorbed, and is dissipated via these holes by means of a suction fan. However, the design of a cooling configuration such as this is very complex.
[0007] In order to improve the cooling in the area of the slip-ring arrangement, DE-A1-32 32 102 describes that each slip-ring be subdivided into a number of individual slip-rings, which are shrunk onto intermediate shrink rings which are isolated from the slip-ring shaft. Cooling air fans are arranged in front and behind the slip-rings on the intermediate shrink rings. This solution also involves a complicated design, and very demanding cooling air routing.
SUMMARY
[0008] In an embodiment, the present invention provides a slip-ring arrangement of a rotating electrical machine. The slip-ring arrangement includes a plurality of slip-rings disposed concentrically about an axis of the electrical machine one behind the other in an axial direction, the plurality of slip-rings configured to be self-supporting.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention will be described in even greater detail below based on the exemplary figures. The invention is not limited to the exemplary embodiments. Other features and advantages of various embodiments of the present invention will become apparent by reading the following detailed description with reference to the attached drawings which illustrate the following:
[0010] FIG. 1 shows a detail of an example of a rotating electrical machine with a slip-ring arrangement of a conventional type;
[0011] FIG. 2 shows the section through a slip-ring arrangement of a conventional type, in the form of a dashed illustration and a flat illustration;
[0012] FIG. 3 shows an illustration, comparable to that in FIG. 2 , of a slip-ring arrangement according to a first exemplary embodiment of the invention;
[0013] FIG. 4 shows a detail view of the slip-ring arrangement shown in FIG. 3 ;
[0014] FIG. 5 shows a perspective side view of a slip-ring arrangement according to a second exemplary embodiment of the invention;
[0015] FIG. 6 shows a section through the slip-ring arrangement shown in FIG. 5 .
DETAILED DESCRIPTION
[0016] An aspect of the present invention is to provide a slip-ring arrangement which avoids the disadvantages of the known slip-ring arrangements in terms of cooling and which is distinguished in particular by a simple design and very simple and effective cooling, and to specify a method for cooling of this arrangement.
[0017] One feature according to an embodiment of the invention is that the slip-ring arrangement is designed to be self-supporting. The self-supporting design of the slip-ring arrangement makes it possible to dispense with a supporting shaft in this area. On the one hand, this results in the slip-rings being highly accessible from all sides, for the contact with a cooling medium. On the other hand, the slip-ring arrangement can be designed to be flexible with a major weight saving, resulting in considerable advantages with respect to the bearing for the machine shaft.
[0018] One embodiment of the slip-ring arrangement according to the invention is distinguished in that the slip-rings are connected to one another forming through-flow openings, which are arranged between the slip-rings, for a cooling medium, in particular cooling air, and are kept separated by spacers which are arranged between the slip-rings.
[0019] In particular in an embodiment, the spacers may comprise spacer rings which have additional spacing elements distributed over the circumference.
[0020] In this case, the cooling medium is routed in a particularly advantageous manner if the additional spacing elements project in the axial direction on both sides of the respective spacer ring, and the additional spacing elements are integrally formed on the respective spacer ring.
[0021] According to another embodiment of the invention, however, it is also feasible for the spacers to have spacing elements which are arranged distributed over the circumference.
[0022] In this case, preferably, the slip-ring arrangement is held together by a plurality of axial tie bolts which are arranged distributed over the circumference, with the tie bolts being passed through the slip-rings and the spacing elements.
[0023] In an embodiment, the slip-ring arrangement is particularly robust if the slip-rings and the spacing elements which are arranged between the slip-rings are pressed together by means of the tie bolts between two end rings which act as pressing flanges.
[0024] In a further embodiment of the invention, the slip-rings are each subdivided into a plurality of separate sub-rings which are arranged concentrically and one behind the other in the axial direction, are connected to one another forming through-flow openings which are arranged between the sub-rings for a cooling medium, in particular cooling air, and kept separated by spacers which are arranged between the sub-rings.
[0025] This allows the slip-rings to be cooled even more effectively.
[0026] Preferably, the spacers for the sub-rings comprise spacing elements which are arranged distributed over the circumference.
[0027] In another embodiment of the invention, the slip-ring arrangement surrounds an internal area, and in that output conductors are routed from the slip-rings to the machine-side end of the slip-ring arrangement in the internal area. This makes it possible to also extend the effective cooling to the output conductors.
[0028] In an embodiment, a method according to the invention for cooling of a slip-ring arrangement according to the invention is characterized in that a cooling medium, in particular cooling air, is introduced in the axial direction into the interior of the slip-ring arrangement, and emerges radially again between the slip-rings and sub-rings.
[0029] In an illustration comparable to FIG. 2 , FIG. 3 and FIG. 4 show a slip-ring arrangement according to a first exemplary embodiment of the invention. In the new design of the slip-ring arrangement 20 , there is no shaft whatsoever as a support for the slip-ring 18 . The slip-rings 18 can be arranged concentrically one above the other, that is to say one behind the other in the axial direction, and can be spatially separated from one another by means of spacer rings 21 located between them. The slip-rings 18 and the spacer rings 21 thus form a self-supporting slip-ring arrangement. Spacing elements 22 which project on both sides of the spacer ring 21 , distributed uniformly over the circumference, are integrally formed on the spacer rings 21 and ensure that annular gap sections are created between each of the spacer rings 21 and the adjacent slip-rings 18 , through which a cooling medium can flow radially along the sides of the slip-rings 18 , and can absorb heat.
[0030] However, in the slip-ring arrangement 20 shown in FIG. 3 and FIG. 4 , not only are the individual slip-rings 18 separated from one another by spacer rings 21 , but the individual slip-rings 18 also consist of a plurality of sub-rings 19 , which are separated from one another by spacing elements 23 which are distributed uniformly over the circumference. This allows the cooling medium or the cooling air not only to flow up between the slip-rings 18 and the spacer rings 21 but also “through” the slip-rings 18 themselves, that is to say through the annular gap sections, which are formed by the spacing elements 23 , between the sub-rings 19 . On the one hand, this results in a more homogeneous distribution of the cooling air and, on the other hand, the surface area via which heat is emitted is considerably enlarged.
[0031] However, the self-supporting embodiment of the slip-ring arrangement according to the invention also makes it possible to comply with the requirement to cool the output conductors, which are routed on the inside of the shaft or of the slip-rings. This can be seen from the exemplary embodiments of the invention illustrated in FIG. 5 and FIG. 6 : The slip-ring arrangement 30 in FIGS. 5 and 6 is likewise designed in a self-supporting manner from four slip-rings 18 , the four which are themselves each subdivided into three sub-rings 19 . In this case, block-like spacing elements 24 distributed over the circumference are used instead of the spacer rings 21 in FIG. 3 , in order to create the required separations and through-flow openings 31 between the individual slip-rings 18 . This results in a larger opening cross section for the cooling air in this area.
[0032] In this exemplary embodiment as well, the sub-rings 19 are separated from one another by spacing elements, thus creating through-flow openings in the form of narrow annular gap sections, through which cooling air can flow. The self-supporting slip-ring arrangement 30 is held together by a plurality of axial tie bolts 27 , which are arranged distributed over the circumference and are passed through the slip-rings 18 , and sub-rings 19 , and the spacing elements 24 . The slip-rings 18 and sub-rings 19 and the spacing elements 24 arranged between the slip-rings 18 are pressed together by means of the tie bolts 27 between two end rings 25 , 26 , which act as pressing flanges, and thus form a mechanically robust unit. The through-flow openings 31 are also provided between the outer slip-rings 18 and the end rings 25 and 26 , in order to ensure adequate cooling on the outside.
[0033] The slip-ring arrangement 30 surrounds an internal area 28 , into which cooling air is introduced axially for cooling, and then emerges radially through the through-flow openings 31 and 32 (cooling medium 33 in FIG. 5 ). The output conductors 29 , which are electrically connected to the slip-rings, can advantageously be laid in the internal area 28 . Since all of the cooling air flows over the output conductors 29 , they are cooled.
[0034] The spacing elements 24 and the spacer rings 21 should be designed to allow insulation, for electrical isolation of the slip-rings 18 . This also applies to the tie bolts 27 .
[0035] In addition to the improved cooling capability, material can also be saved in the described manner because there is no longer any need for a shaft to support the slip-rings 18 . The material saved leads to a cost reduction, and contributes to reducing the load on the machine bearings. Since the slip-rings 18 are generally not located between the bearing points but outside them, they represent a major load on the bearings (tumbling movements). The weight reduction in this area makes it possible to advantageously reduce the forces which act on the bearings.
[0036] While the invention has been described with reference to particular embodiments thereof, it will be understood by those having ordinary skill the art that various changes may be made therein without departing from the scope and spirit of the invention. Further, the present invention is not limited to the embodiments described herein; reference should be had to the appended claims.
LIST OF REFERENCE SYMBOLS
[0037] 10 Rotating electrical machine (for example a synchronous machine)
[0038] 11 Central body
[0039] 12 Rotor laminated body
[0040] 13 Rotor winding
[0041] 13 ′ Rotor end winding
[0042] 14 , 18 Slip-ring
[0043] 15 Stator laminated body
[0044] 15 ′ Stator end winding
[0045] 16 Shaft
[0046] 17 Machine axis
[0047] 19 Sub-ring
[0048] 20 , 30 Slip-ring arrangement
[0049] 21 Spacer ring
[0050] 22 , 23 , 24 Spacing element
[0051] 25 End ring (inner)
[0052] 26 End ring (outer)
[0053] 27 Tie bolt
[0054] 28 Internal area
[0055] 29 Output conductor
[0056] 31 , 32 Through-flow opening
[0057] 33 Cooling medium
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A slip-ring arrangement of a rotating electrical machine includes a plurality of slip-rings disposed concentrically about an axis of the electrical machine one behind the other in an axial direction, the plurality of slip-rings configured to be self-supporting.
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This application is a Continuation Application from U.S. application Ser. No. 09/129,878, filed Aug. 6, 1998 now U.S. Pat. No. 6,539,454, which claims priority from Canadian Application Serial No. 2,233,789, filed Apr. 1, 1998.
The present invention relates to semiconductor memories and, more particularly, to a pipelined data access in a dynamic random access memory.
BACKGROUND OF THE INVENTION
In conventional non-pipelined dynamic random access memories (DRAMs) a data transfer to and from The memory is performed in sequence. That is when a read or a write command is received and an address is made available, the data transfer according to either a read or write command is performed in its entirety before another command is accepted by the memory. This results in subsequent commands being delayed by the time it takes for the current data transfer to complete.
Historically, DRAMs have been controlled asynchronously by the processor. This means that the processor puts addresses on the DRAM inputs and strobes them in using the row address select signal ({overscore (RAS)}) and column address select signal ({overscore (CAS)}) pins. The addresses are held for a required minimum length of time. During this time, the DRAM accesses the addressed locations in memory and after a maximum delay (access time) either writes new data from the processor into its memory or provides data from the memory To its outputs for the processor to read.
During this time, the processor must wait for the DRAM to perform various internal functions such as precharging of the lines, decoding the addresses and such like. This creates a “wait state” during which the higher speed processor is waiting for the DRAM to respond thereby slowing down the entire system.
One solution to this problem is to make the memory circuit synchronous, that is, add input and output latches on the DRAM which can hold the data. Input latches can store the addresses, data, and control signals on the inputs of the DRAM, freeing the processor for other tasks. After a preset number of clock cycles, the data can be available on the output latches of a DRAM with synchronous control for a read or be written into its memory for a write operation.
Synchronous control means that the DRAM latches information transferred between the processor and itself under the control of the system clock Thus, an advantage of the synchronous DRAMs is that the system clock is the only liming edge that must be provided to the memory. This reduces or eliminates propagating multiple timing strobes around the printed circuit board.
Alternatively, the DRAM may be made asynchronous. For example, suppose a DRAM with a 60 ns delay from row addressing to data access is being used in a system with 10 ns clock, then the processor must apply the row address and hold it active while strobing it in with the ({overscore (RAS)}) pin. This is followed 30 ns later by the column address which must be held valid and strobed in with the ({overscore (CAS)}) pin. The processor must then wait for the data to appear on the outputs 30 ns later, stabilize, and be read.
On the other hand, for a synchronous interface, the processor can lock the row and column addresses (and control signals) into the input latches and do other tasks while waiting for the DRAM to perform the read operation under the control of the system clock. When the outputs of the DRAM are clocked six cycles (60 ns) later, the desired data is in the output latches.
A synchronous DRAM architecture also makes it possible to speed up the average access time of the DRAM by pipe lining the addresses. In this case, it is possible to Use the input latch to store the next address which the processor while the DRAM is operating on the previous address. Normally, the addresses to be accessed are known several cycles in advance by the processor. Therefore, the processor can send the second address to the input address latch of the DRAM to be available as soon as the first address has moved on to the next stage of processing in the DRAM. This eliminates the need for the processor to wait a full access cycle before starting the next access to the DRAM.
An example of a three stage column address pipeline is shown in the schematic diagram of FIG. 1 ( a ). The column address-to-output part is a three stage pipeline. The address buffer is the first latch. The column switch is the second latch and the output buffer is the third latch. The latency inherent in the column access time is therefore divided up between these three stages.
The operation of pipelined read may be explained as follows, the column address (1) is clocked into the address buffer on one clock cycle and is decoded. On the second clock cycle, the column switch transfers the corresponding data (D 1 ) from the sense amplifier to the read bus and column address (A 2 ) is clocked into the address buffer. On a clock three, the data (D 1 ) is clocked into the output buffer, (D 2 ) is transferred to the read bus and A 3 is clocked into the column address buffer. When D 1 appears at the output, D 2 and D 3 are in the pipeline behind it. For a more detailed discussion of the present technology, the reader is referred to a book entitled “High Performance Memories” by Betty Prince.
The delay in the number of clock cycles between the latching {overscore (CAS)} in a SDRAM and the availability of the data bus is the “CAS latency” of the SDRAM. If the output data is available by the second leading edge of the clock following a rival of a column address, the device is described as having a CAS latency of two. Similarly, if the data is available at the third leading edge of the clock following the arrival of the first read command, the device is known as having a “CAS latency” of three.
Synchronous DRAMs (SDRAM) come with programmable CAS latencies. As described above, the CAS latency determines at which clock edge cycle data will be available after a read command is initiated, regardless of the clock rate (CLK). The programmable CAS latencies enable SDRAMs to be efficiently utilized in different memory systems having different system clock frequencies without affecting the CAS latency.
There are other ways to divide an SDRAM data path into latency stages. A wave pipeline is shown schematically in FIG. 1 ( b ). A regular clocked pipeline has the disadvantage that the read latency will be equal to the delay of the slowest pipeline stage (i.e. longest delay) multiplied by the number of pipeline stages. A clocked pipeline with adjusted clocks uses clock signals that have been adjusted to each pipeline stage so that longer pipeline stages may be accommodated without impacting the read latency. A longer pipeline stage will be ended with a clock that is more delayed tan a the clock that starts the pipeline stage. A shorter pipeline stage will be started with a clock that is more delayed than the clock that ends the pipeline stage. A disadvantage of this scheme is that different adjustments to the clock are needed for each CAS latency supported by the chip. Also, architecture changes can have a large impact on the breakdown of the latency stages, requiring designers to readjust all the clocks to accommodate the new division of latency stages.
Furthermore there are a limited number of places where a latency stage can be inserted without adding extra latency or chip area. Multiple latency stages have a disadvantage in that not all latency stages will be equal in the time needed for signals to propagate through the stage. Another complication is the need to enable or disable latency stages depending on the CAS latency at which the chip has been programmed to operate.
In the wave pipeline of FIG. 1 ( b ) runs pulses of data through the entire read data path. A wave pipeline relies on an ideal data path length, that is it assumes that all data paths are equal. However, data retrieved from certain memory cells in a memory array will be inherently faster than data retrieval from other memory cells. This is primarily due to the physical location of the memory cells relative to both the read in and read out data path. Thus data must be resynchronized before being output from the chip. This data path skew makes it difficult to safely resynchronize the retrieved data in a wave pipeline implementation.
If address signals are applied to a data path with a cycle time which exceeds the memory access time, then the data which is read from the memory is not output during the inherent delay of the memory core. In other words, in the wave pipeline technique address input signals are applied with a period, which is less than the critical path of the memory core section.
Furthermore as illustrated in FIGS. 2 ( a ) and 2 ( b ) with a slow clock it is necessary to store the output data of the wave pipeline until the data is needed.
SUMMARY OF THE INVENTION
The present invention thus seeks to mitigate at least some of the various disadvantages described with respect to the current art.
In accordance with this invention there is provided pipelined SDRAM comprising:
(a) a memory core;
(b) a read path, defined between an address input port and an I/O data output port;
(c) a plurality of pipeline stages located in said read path, each controlled by a corresponding one of a plurality of asynchronous control signals;
(d) a timing delay element for generating said asynchronous control signals;
(e) latches associated with each of said plurality of pipeline stages responsive to said asynchronous control signal to latch data at each of said stages; whereby data is latched at every pipeline stage independent of said system clock.
In accordance with a further aspect of this invention the asynchronous control signals are generated within the chip and optimized to the different latency stages.
A still further aspect of the invention provides stages that are independent of the system clock thereby allowing the read data path to be run at any CAS latency which may be supported by a suitable resynchronizing output.
A still further aspect of the invention provides for a synchronization circuit coupled to the end of the read data path for synchronizing the output data to a system clock
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the invention will be obtained by reference to the detailed description below in conjunction with the following drawings in which:
FIG. 1 ( a ) is a schematic diagram of a conventional clocked pipeline memory circuit;
FIG. 1 ( b ) is a schematic diagram of a conventional wave pipeline memory circuit;
FIGS. 2 ( a ) and 2 ( b ) are timing waveforms for a SDRAM having a CAS latency of 3 running under fast and slow clock conditions respectively;
FIG. 3 is a schematic diagram of a generalized embodiment of the present invention;
FIGS. 4 ( a ) and 4 ( b ) are more detailed schematic diagram of the generalized embodiment of FIG. 3;
FIG. 5 is a timing waveform diagram according to a first embodiment of the present invention;
FIGS. 6 ( a ), 6 ( b ) and 6 ( c ) show detailed circuit diagrams of a pipe control circuit according to an embodiment of the present invention;
FIGS. 7 ( a ), 7 ( b ) and 7 ( c ) show detailed circuit diagrams for a pipe latch and data output latch according to an embodiment of the present invention; and
FIG. 8 is a schematic diagram of a data output control circuit according to an embodiment of the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In the following discussion, like numerals refer to like elements in the figures and signals asserted low are indicated interchangeably with an x or an overscore associated with the corresponding signal name. Referring now to FIG. 3, a schematic diagram of a pipelined semiconductor memory according to a generalized embodiment of the invention is shown generally by numeral 20 . The memory includes a core memory array 22 having a read path 24 , defied between an address input port 25 and a data output 32 . The read path 24 is broken up into latency stages 27 , each of which is latched by respective asynchronous control signals 28 . A synchronizing circuit 30 is coupled to the last latency stage of the read path in order to resynchronize the data to the system clock CLK at output 32 of the read path. The data is synchronized to the system clock CLK a predetermined number of clock cycles after the application of an address signal A to the address input 25 , i.e depending on the CAS latency of the system. The segmentation of the read path 23 into the three main latency stages, each controlled by respective control signals 28 illustrates, in general, the combining of clocked and wave pipeline techniques to achieve an asynchronous pipeline implementation according to the invention which exhibits less skew than a conventional wave pipeline but which allows for operation with any CAS latency without having to adjust individual clocks in each stage as would be required in a clocked pipeline implementation. The description with respect to FIG. 3 serves to provide an overview of the detailed circuits discussed below.
Thus, refining to FIG. 4 a detailed schematic diagram of the generalized embodiment of FIG. 3 is shown by numeral 40 . The latency stages 26 in FIG. 3 include an address input latch 42 , for receiving an address signal A i at the address input port 25 , the output of which is coupled to an address pre-decoder latch 44 which is in turn connected to a column address decoder latch 46 . The column address decoder latch 46 decodes the address signal and is coupled to select memory cells 48 in the memory cell array 22 . The column address decoder 46 activates relevant sense amplifiers (not shown) for detecting the data read out from a selected memory cell 48 . The output of the sense amplifiers is coupled to a read main amplifier block 50 via a local databus DB, which is 32-bits wide in this embodiment. The output of the read main amplifier 50 is coupled to a global databus GDB. A multiplexer 52 multiplexes the GDB onto an I/O databus IODB, which is in turn coupled to a read databus amplifier RDBAMP latch block 54 .
The synchronizing circuit 30 of FIG. 3 is comprised of pipe latches 56 , an output buffer 58 and control circuitry shown by block 61 More specifically, the output from the RDBAMP latch is selectively coupled to the input of three pipe latches pipe_latch 0 , pipe_latch 1 and pipe_latch 2 as will be described below. The outputs from the pipe latches are connected together and coupled to the input of the output buffer 58 .
The memory also includes a command latch circuit 62 having a clock input terminal coupled to the system clock CLK and a command input terminal for receiving command signals such as {overscore (RAS)}, {overscore (CAS)}, {overscore (CS)}. The command latch 62 provides a first control signal 64 , which is run through a series of control logic and delay elements T 1 to T 4 . Each of the delay elements T 1 , T 2 , T 3 and T 4 produce respective delayed control signals that are fed to an input latch terminal of the pre-decoder latch 44 , the Y decoder 46 , the RMA 50 and the RDBAMP latch 54 , respectively. These signals serve as individual asynchronous control signals for these circuits. On the other hand, the address latch clock input is derived directly from the system clock signal CLK.
Control of the pipe latches pipe_latch 0 , pipe_latch 1 and pipe_latch 2 is provided by the pipe latch control circuitry 61 . Each pipe latch is driven by a respective pipe latch enable signal, latch_enx( 0 ), latch_enx( 1 ) and latch_enx( 2 ) coupled to its latch input enable terminal. The pipe latch enable signals are derived from a pipe counter 64 which produces three count signals COUNT. The pipe counter is a free running counter which resets its count based on the total number of pipe latches. After a preset number of clock counts set by the system clock signal coupled to the pipe counter clock input terminal. The output COUNT signals from the pipe counter are coupled via count delay elements 66 to count synchronization latches 68 . The outputs from the three latches 68 provide the pipe latch enable signal for clocking the appropriate pipe latch 56 . The clock input enable terminal of the lathes 68 are coupled to the asynchronous control signal of the latency stage in the read path, in this case, signal IODB_READX of the RDBAMP 54 to ensure the pipe latch is latched at the appropriate time.
Alternatively, a more accurate synchronization of the data IODB_READX and the CNT_DEL signals in latch 68 can be achieved as follows:
the count delay circuitry 66 could be segmented into multiple delay stages, each receiving control logic enable signals such as YSG or Y_EXTRD. The timing relationship between the address propagation and data retrieval and the clock count delay would therefore be more closely matched.
Additionally, the output COUNT of pipe counter 64 is connected to a pipe delay element 70 for generating a pipe latch output enable signal QEN_RISEX which is connected to the respective output enable terminal of the pipe latches 56 . A CLK_IO signal which is DLL generated and slightly leads the system clock CLK, is coupled to an output enable terminal of the pipe delay and the output buffer 58 . The DLL (delay locked loop) ensures that CLK_IO will enable the output buffer to properly synchronize data with the system clock edge.
The operation of the circuit will be explained as follows with reference to the timing diagram shown in FIG. 5 . At time to of the system clock signal CLK the address latch 42 latches the external address signal A i , which is then free to propagate to pre-decoder latch 44 which latches the address after a delay T 1 set by the delay element T 1 . These address signals are decoded in the Y decoder 46 and latched by the signal YSG delayed from CLK by T 1 and T 2 . At this time the appropriate columns are activated and data is read out from the memory cells into column sense amplifiers and then latched in the RMA 50 by the IOREAD signal which is delayed from CLK by T 1 +T 2 +T 3 . Shortly thereafter, the data is available on the global data bus GDB. The RDBAMP 54 may now be latched at time t 1 by signal IODB_READ that is delayed from IOREAD by T 4 , to provide the DOUTE signal.
In general as described above, these asynchronous control signals are used to control the pipeline stages. These signals control when data is read into the latch (usually a latched amplifier). Once read into the latch, data is free to propagate toward the next stage. Each control signal is generated by delaying the control signal from the previous latency stage. The first stage is started by the external clock CLK. The next stage will latch data from the previous stage on the control signal that is delayed from the external clock. It may be noted that some of these delays are inherent in the circuits used to control whether a read is to take place, while some of the delays are deliberately added using timing delay elements. These are usually comprised of buffers sized to run slowly and which may include additional resistive or capacitive elements.
Thus the delays T 1 to T 4 can be optimized to the particular memory independent of the external clock timing. The delay for each of these latches is selected to accommodate the propagation delays between these blocks. Thus the clock signal applied to the read main amplifier latch is synchronized and delayed from the clock signal applied to the column decoder latch to accommodate the lag in retrieving data from different areas of the memory array 22 to the read main amplifier 50 .
The data once latched in the RDBAMP 54 at time t 1 , must as with the conventional wave pipelines, be resynchronized to the system clock CLK at the output 32 of the memory. This is accomplished as follows. The pipe latches 56 allow data to be stored in the event of fast data or a slow clock. Generally, the number of latches needed is equivalent to the number of latency stages to be supported. Each time a read is performed, a COUNT signal, one of these is shown in FIG. 5, is delayed asynchronously by the count delay element 66 and clocked by the control signal for the last stage in this case {overscore (IODB_READ)} into a clock synchronizing latch 68 . This time delayed COUNT signal generates {overscore (LATCH_EN)} which determines which of the latches 56 the data from RDBAMP 54 is to be stored in. Furthermore the COUNT signal is also delayed by the appropriate number of clock cycles, as determined by the current CAS latency to which the chip is programmed. This clock delayed COUNT signal shown as {overscore (QEN_RISE)} in FIG. 5 controls which of the latches 56 has its output enabled to output data to the output buffer 58 . Once COUNT has been set, after the delay through count delay circuitry 66 , a CNT_DEL signal is generated which is combined in the clock synchronizing latch 68 with the IODB_READX signal to generate the LATCH_ENX signal. After the predetermined clock delay in the pipe delay circuit to QEN_RISEX is asserted allowing output form the latch containing the data for the appropriate clock cycle. The latches 56 work as a FIFO register, with the first data input to one of the set of latches 56 , being the first data to be output from the set of latches.
Thus from the above description it may be seen that the latches in the read path, segment the path into latency stages of an asynchronous pipeline. The chip architecture and the maximum operating frequency determine the number and placement of these stages. In general, a higher operating frequency will require a large number of shorter pipeline stages. Other techniques can be used such as doubling the number of data paths in a stage and alternating between the data paths. For example, a read output from the sense amplifiers is alternated between two data buses. This is described in Mosaid U.S. Pat. No. 5,416,743. The placement of the stages will generally be dictated by the position of amplifiers or buffers, which may be converted into latches without resulting in extensive area penalty. For clarity, in the previous and following discussion latency stages refer to any circuit element capable of introducing a delay in the signal or data path.
Turning now to FIGS. 6 to 8 , a detailed implementation of the generalized embodiment of FIG. 4 is shown. Accordingly, referring to FIG. 6 a , the pipe control circuitry 61 includes a pipe counter 90 , a detailed schematic of which is shown in FIG. 6 b , for producing a two digit binary count, COUNT 0 and COUNT 1 , determined by the input system clock frequency at its clock input terminal CLK. Each of the count lines, COUNT 1 and COUNT 0 are connected to respective count delay elements 92 and 94 . The delayed count signals are connected to a count decoder 96 which decodes the input binary count to activate one of the three count delay lines 98 , CNT 0 _DEL, CNT 1 _DEL, CNT 2 _DEL. The signals on these delayed count lines 98 correspond to the COUNT signal as shown in FIG. 5 . In FIG. 5, all elements were shown with only one of the three components for simplicity with the exception of the three pipe latches. The delayed COUNT signals 98 are coupled to the inputs of respective clocked latches 100 , the outputs of which are buffered and provide the respective latch enable signal referred to in FIG. 5, LATCH_ENX( 0 ), LATCH_ENX( 1 ), LATCH_EN( 2 ). The clock input terminal of these latches 100 is coupled to the {overscore (IODB_READ)} asynchronous control signal from the last latency stage via an inverter.
The pipe counter 90 also has its output connected to a second decoder 102 also providing respective count signals, CNT 0 , CNT 1 and CNT 2 , which are coupled to respective pipe delay elements 104 , 106 and 108 . A detailed circuit diagram of the pipe delay circuit implementation is shown in FIG. 6 c . The output of the pipe delay is controlled by a CLK_IO signal and generates the {overscore (QEN_RISE)} signal referred to in FIG. 5 connected to the output latch enable of the pipe latches 56 . Corresponding {overscore (QEN_FALL)} signals are generated for the falling edge of the system clock whereas {overscore (QEN_RISE)} corresponds to the rising edge of the system clock.
Referring to FIGS. 7 a and 7 b , a detailed schematic of the pipe latches 56 and the output buffer circuitry is shown. As may be seen in FIG. 7 a , the data bits from the IODB databus are received at the input of the RDB amplifiers 110 . Two RDBAMPS are shown in this implementation because of the double data rate (DDR) where data is clocked on both the rise and fall edges of the system clock. The outputs from the RDBAMPS are connected to a series of six pipe latches 112 to 122 . Six latches are required instead of three due to the DDR implementation. The enable inputs of the pipe latches 112 to 122 are coupled to the respective latch enable signals derived from the circuit of FIG. 6 a . The top three pipe latches 112 to 116 have their outputs connected to inputs of a 3 OR 2 NAND gate 124 . Similarly, the bottom three latches 118 to 122 have the outputs connected to a 3 OR 2 NAND gates 126 . The {overscore (QEN_RISE)} signal is connected to the inputs of the 3 OR 2 NAND gate 124 , the output of which, when enabled, couples data to the DOUT_RISE, DOUT_RISEX input of the output buffer shown in FIG. 7 b . As may also be seen in FIG. 7 a , a system clock control signal EDGE is provided for directing data to the top three or bottom three latches, once again a DDR feature. Also, for a fast system clock relative to the speed of the data path the 3 OR 2 NAND gates 124 or 126 will be already on thus allowing data to pass through to the output buffer from the pipe latches. In the alternative, with a slow clock, the system receives the data and waits for the clock, thus utilizing the 3 OR 2 NAND gates 124 or 126 . Turning back to FIG. 7 b , the data output buffer 58 as shown in FIG. 4 is comprised of data output latches 130 to 136 . The input enable terminals of the data output latches 130 to 136 are coupled to the CLK_IO signal for synchronizing to the correct system clock edge. A detailed circuit implementation of the pipe latches 112 to 122 is shown in FIG. 7 c.
Thus, it may be seen data the present invention provides a flexible method for implementing a pipelined semiconductor memory, which can easily accommodate both a fast and slow system clock. Furthermore, the flexible design allows further segmentation of the read path for more precise matching of internal signals. Furthermore, various CAS latencies may be accommodated by simply delaying the output from the pipe delay element 70 to wait a specific number of clock cycles before clocking the data out.
Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the spirit and scope of The invention as outlined in the claims appended hereto.
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An asynchronously pipelined SDRAM has separate pipeline stages that are controlled by asynchronous signals. Rather than using a clock signal to synchronize data at each stage, an asynchronous signal is used to latch data at every stage. The asynchronous control signals are generated within the chip and are optimized to the different latency stages. Longer latency stages require larger delays elements, while shorter latency states require shorter delay elements. The data is synchronized to the clock at the end of the read data path before being read out of the chip. Because the data has been latched at each pipeline stage, it suffers from less skew than would be seen in a conventional wave pipeline architecture. Furthermore, since the stages are independent of the system clock, the read data path can be run at any CAS latency as long as the re-synchronizing output is built to support it.
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FIELD OF THE INVENTION
The invention concerns a method for manufacture of a calender roll provided with an elastic coating, in which method the roll frame is composed of a continuous axle and of a filler material fitted onto the axle.
The invention also concerns a calender roll manufactured in accordance with the method, comprising a continuous roll axle, a filler material fitted onto the axle, which filler material, together with the axle, forms the roll frame, and an elastic polymer coating fitted onto the roll frame.
BACKGROUND OF THE INVENTION
A supercalender normally comprises a stack of rolls consisting of a number of rolls fitted one above the other, in which stack, between the upper roll and the lower roll in the calender, there are a number of intermediate rolls, which are alternatingly chilled rolls and soft-faced rolls. Earlier, as soft-faced rolls, almost exclusively so-called fibre rolls were used, which consisted of disks or rings of fibrous material fitted on the roll axle and pressed together axially by means of end pieces and end nuts so that the soft face of the roll consisted of said fibre disks. It was one drawback of such fibre rolls that the deflections and rigidities of said fibre rolls differed quite substantially from corresponding properties of the chilled rolls, because the frame of the fibre rolls is quite slender as compared with the chilled rolls. As second significant drawback was relatively rapid wear of the fibre rolls.
Development of rolls and roll coatings made it possible, in supercalenders, in stead of fibre rolls, to employ rolls provided with elastic coating, in particular with a polymer coating, as soft rolls. In such rolls, the thickness of the coating in relation to the roll diameter is quite little, in which case the roll frame can be made quite rigid. Thus, in particular when rolls with polymer faces are employed, the rolls can be constructed so that the rigidities and deflections of all of the intermediate rolls in the calender are substantially equal, or at least the differences in these properties from roll to roll are quite little. It is a second improvement in polymer-coated rolls, as compared with fibre rolls, that their service life is considerably longer, i.e. the intervals of replacement of rolls can be made considerably longer.
In conventional rolls with polymer coatings, a significant problem, however, consists of the relatively high weight of the rolls as compared with fibre rolls. Thus, these polymer-coated rolls of novel type cannot be used as such in renewals and modernizations of existing calenders in which fibre rolls were used as soft-faced rolls earlier. This comes simply from the fact that, in a calender which was originally designed so that fibre rolls are employed as intermediate rolls, the mechanical strength of the spindles and spindle nuts on whose support the rolls are suspended does not endure the increased weight resulting from the polymer-faced rolls. Thus, in modernizations of supercalenders, if it is desirable to employ polymer-coated rolls of new type, considerable changes and renewals must be carried out in the frame constructions of the calender and in the means of suspension of the rolls. Thus, it is an aim to be able to reduce the weight of the polymer-faced rolls employed in supercalenders substantially in order that such rolls, whose other properties are better than those of fibre rolls, could be used simply also in modernizations of supercalenders.
With respect to the prior art, reference is made to the U.S. Pat. No. 3,711,913, to the DE Patent 195 11 595 (corresponding to U.S. Pat. No. 5,766,120), to the published DE Patent Application 195 33 823 (corresponding to U.S. Pat. No. 5,759,141), and to the published EP Patent Application 735,287 (also corresponding to U.S. Pat. No. 5,766,120).
In said U.S. Patent, a method is described for conditioning of a fibre roll, in which method a worn or damaged fibre roll is machined to a measure smaller than its original diameter, after which a coating of a synthetic plastic material is fitted onto the roll, i.e. directly onto the fibre disks. With this procedure, the roll can be made suitable for a certain purpose of use, but the properties of a roll manufactured or conditioned in compliance with said method do not correspond to what is required from a modern polymer-faced calender roll. First, the rigidity of the roll is considerably lower than the rigidity of a tubular polymer roll, and further, since the coating has been fitted directly onto the fibre disks, the properties of resilience of the roll differ considerably from what is expected, for example, from a modern tubular polymer roll.
In the DE and EP publications referred to above, polymer-faced calender rolls are described which have been formed so that, in the roll, the axle of an existing fibre roll is used so that, onto the axle, in place of the filler material of the fibre roll, for example, disks made of aluminum cell material are fitted, in which disks at least a part of the walls of the cells are perpendicular to the roll axle. Then, onto these disks, an elastic polymer coating has been fitted. The roll formed in this way has quite good properties, in particular because the weight of the roll has become so low that it can be utilized easily in renewals of supercalenders, because the difference in weight of the roll as compared with a fibre roll is very little. It is a significant drawback of these rolls that, according to a first embodiment, the roll is manufactured by pressing loose disks between locking flanges, as is the case in traditional paper rolls, in which case it is very difficult to provide the desired rigidity. The rigidity is determined in accordance with the pre-stress of the axle and with the compression strength of the disks, as is the case in traditional paper rolls. In a second embodiment desribed in the cited prior-art publications, the support construction is composed of a plate of cellular construction which is wound as layers onto the axle. In the embodiment described in the publications, this procedure requires formation of joints in the longitudinal direction of the roll and bending of large plate-like pieces into correct shape, which requires high precision and care of manufacture. A further drawback is the high cost, which comes, besides from the above reasons, also from the technique of manufacture that has been used, which requires casting and machining of the disks. Also, depending on the purpose of use and on the diameter of the roll, the disks must always be designed anew, and a number of different cast models must be prepared for different rolls. In said publications, as a further alternative embodiment, forming of disks has been suggested out of a material that contains reinforcement fibres, such as epoxy reinforced with fibreglass, carbon fibres, aramide fibres, or equivalent. Such solutions are, of course, usable in themselves, and they provide a roll of quite low-weight construction, but the problem is an even higher cost.
The object of the present invention is to provide a novel method for manufacture of a calender roll provided with an elastic coating as well as a calender roll manufactured in accordance with the method, which method and roll do not involve the drawbacks involved in the prior art and by means of which method and roll, further, a significant improvement is achieved over the prior art. In view of achieving the objectives of the invention, the method in accordance with the invention is mainly characterized in that the filler material is made of a continuous profile band, which is wound onto the axle as the desired number of windings in order to produce the desired roll diameter, in which connection an elastic coating is formed onto the cylindrical outer face of the filler material.
OBJECTS AND SUMMARY OF THE INVENTION
On the other hand, the calender roll in accordance with the invention is mainly characterized in that the filler material has been made of a uniform and continuous profile band, which has been wound onto the axle as the desired number of windings in order to produce the desired roll diameter.
The invention provides significant advantages over the prior art, and of the advantages obtained by means of the invention, for example, the following can be stated. First, the manufacture of the roll in accordance with the invention is very easy. Owing to this easy mode of manufacture and, also, of the materials employed, the cost of manufacture of the roll is essentially low, as compared with the prior art described above. The roll produced in accordance with the present invention is of low-weight construction, owing to which it can be employed readily in modernizations of supercalenders as substitution for earlier fibre rolls. The properties of operation of the roll, however, meet the requirements imposed on a modern polymer-coated tubular roll. Owing to the winding technique that is employed, the rigidity of the roll can be made fully as desired, and in particular if the layers that are wound are glued or welded together, the construction of the roll becomes highly rigid. Further, since the roll has been formed by means of the winding technique and since the intermediate layers have been locked from their ends directly on the roll axle or on a lower intermediate layer, no locking flanges are needed, but the roll frame itself forms a struture that remains in its position on the axle, and the end flanges, if any, operate just as a piece for the supply of a cooling/heating medium to the roll frame. This is why the end pieces of the roll are just covering flanges and fixed to the profile bands only, and not at all fixed to the axle. The firrer advantages and characteristic features of the invention will come out from the following detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following, the method in accordance with the invention and the calender roll manufactured in compliance with the method will be described in more detail with reference to the figures in the accompanying drawing.
FIG. 1 is a schematic illustration partly in section of a roll in accordance with the invention.
FIG. 2 is a schematic illustration of an embodiment of a roll in accordance with the invention.
FIG. 2A is a detail from FIG. 2 .
FIG. 3 shows a further embodiment in a roll as shown in FIG. 2 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, the roll is denoted generally with the reference numeral 10 . The roll 10 has preferably been formed so that, in the manufacture of the roll 10 , an existing fibre roll has been used, from which the fibre disks have been removed. Thus, as the starting point of the novel method, the axle of such a fibre roll has been adopted, which axle is denoted with the reference numeral 11 in the figure. This axle 11 has been mounted in a winding machine, and in the winding machine the desired number of layers of a profile band 13 have been wound onto the axle 11 , one layer onto the other, so that said layers of profile band 13 form a filler material onto the axle 11 , which filler material, together with the axle 11 , forms the roll frame. Then, onto this roll frame, a resilient polymer coating 14 has been applied fully similarly to the way in which it is currently applied onto tubular polymer rolls. The reference numeral 12 denotes the end pieces of the rolls 10 , taken as such from the old fibre roll.
The profile band 13 is favourably made of aluminum material, because this material is already in itself of low weight and because, out of said material, a band of the desired profile can be prepared by extruding. The band can also be made, for example, by rolling, but an extrusion process is preferable exactly because by its means, for example, a hollow profile of the sort illustrated in the figure in the drawing can be obtained, in which case the filler material of the roll becomes of even lower weight. By varying the shape of the profile, it is possible to optimize the amount of material and the amount of air in the filler material, by which means it is, in a simple way, possible to affect the weight of the filler material and of the whole roll. The filler material or, in fact, the weight of the filler material must be optimized so that it endures all the loads applied to the roll 10 but does not have any extra weight. The mass of the filler material and the additional rigidity of the roll frame obtained by means of the filler material are preferably optimized so that the natural deflection of the roll arising from its own weight is substantially equal to the corresponding deflections of the other rolls in the calender. By means of this system, it is very easy, by slightly altering the extrusion tool, to change the material-to-air ratio of the filler material without any machining operations. The filler material made of the profile band 13 is particularly advantageous also because the diameter of the roll frame can be regulated by varying the number of winding layers of the profile band 13 or by varying the height of the profile to be wound. Thus, all different dimensions of rolls can be accomplished by means of one and the same profile, in which case manufacture of the rolls is highly advantageous.
A roll manufactured in the way in accordance with the invention already becomes very robust in itself and endures loading very well. The load holding capacity and the robustness can be increased substantially, for example, so that, in connection with the winding, the profile band is immersed in an adhesive agent, in particular epoxy, whereby the wound profile band is glued into a solid “package” and forms a robust roll frame. It is also possible to think that the layers of profile band, or at least the topmost layer, are/is welded, in which case the layer forms a good foundation for the roll coating 14 . It is a significant additional property of the roll in accordance with the invention that, as the profile is hollow and tubular in the way illustrated in the figure, some medium can be passed to flow inside the profile, such as air or water, which medium transfers heat and equalizes differences in temperature in the roll. In particular in cases in which there is an even number of winding layers, the heat transfer medium runs back and forth from end to end in the roll, in which case the temperature profile of the roll becomes highly uniform.
In FIGS. 2 . . . 3 in the drawing, an additional embodiment of a roll is shown, which is denoted generally with the reference numeral 20 . FIGS. 2 and 3 illustrate the roll without a roll coating, which coating is, however, also supposed to be used in the solution in accordance with these figures. FIG. 2A shows a detail from FIG. 2 . The embodiment shown in FIGS. 2 and 3 differs from FIG. 1 in particular in the respect that, in the embodiment that is now being discussed, the profile bands 23 have been wound as filler material onto the roll or at least as the outer layer of the filler material, substantially less steeply than in the embodiment shown in FIG. 1 . As a matter of fact, in the embodiment shown in FIGS. 2 and 3, the direction of the threading of winding differs from the axial direction of the roll to a substantially lower extent than it differs from the direction transverse to said axial direction. By means of this solution, attempts have been made to improve and to facilitate the introduction of the heat transfer medium into the ducts 23 a in the profile band 23 and the circulation of said heat transfer medium in the ducts. Circulation of such a heat transfer medium in the ducts 23 a in the profile band is advantageous, for example, when it is desirable to use a heat transfer medium for cooling of the roll and in particular of the roll coating, because an excessive heating of the coating makes the wear quicker and may result in damage to the coating in a very short time. As was already stated earlier, it is preferable to make the profile band 23 out of aluminum material by extrusion, because in such a case the profile band can be provided with the desired shape very easily.
As a preferred solution of the shape of the profile band, in FIG. 2A a shape of the profile band is illustrated owing to which the profile band is “self-locking” so that adjacent profile bands are attached to one another because of their shape. In the attaching, gluing can also be employed as an aid, and, as an additional alternative, it is further possible to employ friction welding of the profile band at least in the outermost layer of the filler material. In such a case, the manufacture of the roll could be made automatic so that friction welding is carried out at the joints 25 between adjacent profile bands 23 in connection with the winding. As was already stated above, in the solution of FIGS. 2 and 3, the profile band 23 has been wound as very gently inclined at least in the outermost layer of the filler material. It is not advantageous the arrange the profile bands 23 fully axially, because such an axial alignment might cause vibration in the roll during operation and also a barring pattern in the paper. Such drawbacks can be avoided even with a slight spiral form of the profile band.
FIG. 3 is a schematic illustration of a solution of how a heat transfer medium can be passed into the ducts 23 a in the profile bands 23 . This has been accomplished simply so that, into the roll 20 axle 21 , or at least into the end of the axle, a duct or bore has been formed for the heat transfer medium, and similarly, into the end piece 22 of the roll, a necessary system of ducts 26 has been formed, which communicates with the bore that has been formed into the axle 21 , on one hand, and with the ducts 23 a in the profile bands 23 , on the other hand. Further, to the end of the axle 21 , a water couping 27 or equivalent has been connected, by whose means the heat transfer medium is passed into the roll.
The shape of the profile band 13 does not necessarily have to be a hollow profile similar to that shown in the figures, but, as the profile, it is also possible to employ an open profile, for example an I-section profile. Such a profile is very easy to produce, besides by means of extrusion, also by rolling. When such an open profile is wound onto the axle side by side, between the profiles, ducts remain which are closed ducts. In particular in cases in which the medium that is circulated in the ducts is air, such an open profile operates very well, in particular in cases in which, in connection with winding, gluing is also employed, as was already explained earlier. As the preferred materal alternative for a profile band, aluminum material can probably be considered, even if other materials can also be considered to be employed in the roll. The material must, however, be such that, out of the material, such a profile band can be formed readily in which, at least in connection with winding, ducts can be formed in the filler material, as was described above. Of materials that can be thought of, it is possible to mention, for example, different polymer materials, even though a limiting factor in their case is a cost substantially higher than the cost of aluminum.
It is a further feature of the roll in accordance with the invention that, in cases in which a heat transfer medium is made to flow in the ducts in the filler material, the heat transfer medidn can be utilized for heating of the roll at least during the starting stage of the calender, in which case said start-up stage can be made shorter. Further, it is evident that the heat transfer medium can also be used for cooling the roll.
Above, the invention has been described by way of example with reference to the figure in tihe accompanying drawing. The invention is, however, not confined to the exemplifying embodiment illustrated in the figure alone, but different alternative embodiments of the invention may show variation within the scope of the inventive idea defined in the accompanying patent claims.
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A method for manufacturing a calendar roll in which a continuous band of filler material is wound onto an axle until a desired diameter for the roll is obtained, and then an elastic coating is applied to an outermost surface of the band, i.e., the outermost layer of windings. An adhesive agent may be applied onto the band such that adjacent windings of the band adhere to one another during winding of the band onto the axle. Adjacent windings of the band in an uppermost layer of windings may be welded together to provide a foundation for the elastic coating. The calender roll includes an axle, a uniform and continuous band of filler material wound onto the axle to provide the roll with a desired diameter, and an elastic polymer coating arranged on an outermost layer of windings of the band on the axle.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No. 419,875, filed Oct. 11, 1989, now abandoned. It is also a continuation-in-part of Ser. No. 07/625,289, filed on Dec. 10, 1990, also now abandoned.
FIELD OF THE INVENTION
This invention is directed to a method for the recovery of viscous hydrocarbonaceous fluids from a formation. More specifically, it is directed to the removal of said fluids from a formation containing heavy viscous hydrocarbons by the application of conduction heating through steam circulation within the horizontal wellbore in a manner to prevent water coning.
BACKGROUND OF THE INVENTION
The use of horizontal wells in oil reservoirs is currently of high interest within the oil industry. Horizontal wells allow more reservoir surface area to be contacted and thereby reduce inflow pressure gradients for reasonable oil production rates. Alternatively, for typical pressure gradients within the wellbore region, the productivity of a horizontal well is greater than that in a vertical well.
Several possible benefits of horizontal wells are currently being exploited in the Canadian tar sands. Reservoirs in Canada that may be categorized as immobile under reservoir conditions include the Cold Lake and Athabasca deposits. Horizontal wells are also being used to produce mobile viscous oil from a formation.
Current practices for producing the above immobile tar sands and mobile viscous oils include mining and steam stimulation by formation fracturing. However, mining is not practical below very shallow depths. Furthermore, steam stimulation by formation fracturing is not feasible in those reservoirs underlain by water aquifers. In general, fracturing in zones underlain by water aquifers or a bottom water zone results in large amounts of water production and non-uniform development of the steam zone. Large water influx is due to penetration of the fracture into the water aquifer and water coning around the wellbore.
Water coning is the phenomenon whereby water is drawn upwardly from the water-bearing portion into the oil-bearing portion about the well.
Steam stimulation below fracture pressure in a vertical well is not practical due to the very low injectivity of the formation to steam and the very small area of reservoir contact. Increased area of contact can be achieved by the use long horizontal wells (1,000 to 3,000 feet as compared to 30 to 100 feet for a vertical well). This increased area of contact allows more of the reservoir's area to be heated by steam injection. This results in more oil production due to increased volume of the heated zone. Injection of a large steam slug into a horizontal well underlain by a water aquifer may result in a fracture into the aquifer.
The length of horizontal wells permits smaller inflow pressure gradients during isothermal viscous oil production. However, the shape of the pressure profile around the wellbore remains logarithmic such that the largest pressure gradients occur in a near-wellbore region. Hence, water coning, while reduced in horizontal wells compared to vertical wells is still quite a problem in viscous oil reservoirs, since a sharp pressure sink exists in the near-wellbore region.
Therefore, what is needed is a method to reduce water coning in a horizontal well so as to obtain an increased production of hydrocarbonaceous fluids from a heavy oil reservoir.
SUMMARY OF THE INVENTION
This invention is directed to a process for reducing water coning in a well when heating a reservoir at below fraction pressure in a very viscous hydrocarbonaceous fluid-containing formation, where at least one horizontal wellbore is utilized. A horizontal well is drilled into the formation. Steam is then circulated down an inner insulated tubing string to the far end of the horizontal portion of the wellbore. Steam then circulates back along the inside of a slotted liner completion. Steam does not penetrate through the slots in the slotted liner. Finally, steam passes up a return tubing string to the surface. This circulation of steam within the horizontal section provides a large temperature gradient from the wellbore to the formation. Hence, the horizontal section of the wellbore apparatus acts as a heat conductor, since no steam actually flows away from the wellbore into the formation. Circulation continues for a period greater than about two to five years.
Once sufficient reservoir heating is obtained, oil production is commenced by either artificial lift or natural drive lift aided by simultaneous steam circulation. Steam circulation is also continued during the artificial lift production phase. Viscous oil formation surrounding the wellbore is not heated by steam flow from the wellbore. Rather, heat flows away by conduction due to the large temperature difference between the wellbore and a virgin formation.
While circulating steam into and out of the wellbore, inflow pressure gradients are substantially reduced while simultaneously producing hydrocarbonaceous fluids to the surface. Simultaneous heating and producing of hydrocarbonaceous fluids from the reservoir results in a reduction of inflow pressure gradients in the near wellbore region which causes a smearing or spreading out of the pressure sink associated with the wellbore itself. Therefore, water coning, which results from a sharp pressure sink or high inflow pressure gradients, is substantially reduced.
This reduction in water coning allows for a substantial increase in hydrocarbonaceous fluids production from the viscous oil reservoir before water breaks through into the horizontal well. Additionally, when water breaks through, by maintaining simultaneous heating while producing hydrocarbonaceous fluids, the amount of water produced with the hydrocarbonaceous fluids is substantially reduced. This allows for increased volumes of hydrocarbonaceous fluids to be produced before reaching an uneconomically high water to oil ratio.
It is therefore an object of this invention to reduce water coning in a horizontal well when producing hydrocarbonaceous fluids therefrom.
It is another object of this invention to reduce water coning in a horizontal well penetrating a viscous hydrocarbonaceous fluid-containing reservoir by simultaneously heating said well while producing fluids therefrom.
It is yet another object of this invention to flatten or spread out a pressure sink in a near-wellbore region so as to reduce water coning in a heavy or viscous oil reservoir underlain by a bottom water zone or an aquifer.
It is yet another object of this invention to delay a high water to oil ratio when producing a viscous oil reservoir by reducing or delaying water coning.
It is still another object of this invention to simultaneously heat and produce a near-wellbore area of a horizontal well to reduce water coning in a viscous or heavy oil formation during primary oil production.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of the apparatus whereby steam circulation is made possible for conduction heating in a horizontal wellbore.
FIG. 2 is a graphical illustration depicting heat front (temperature) movement by conduction from the wellbore into the reservoir.
FIG. 3 represents graphically comparative calculated pressure distributions for a heated steady state, a heated pseudo-steady state, and a cold steady state.
FIG. 4 illustrates schematically water coning at different times along a horizontal well during isothermal viscous oil production.
FIG. 5 depicts graphically initiation of broader cones at different times during simultaneous heating and producing in a viscous oil reservoir.
FIG. 6 demonstrates graphically oil viscosity distribution around a horizontal wellbore in space and time.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the practice of this invention, referring to FIG. 1, steam is circulated down insulated injection tubing 10 which penetrates through surface casing 14 and intermediate casing 18 into oil bearing formation 12. Liner top 22 is fittingly affixed to intermediate casing 18. Liner top 22 is affixed to slotted liner 16 and penetrates oil bearing zone 12. Insulated injection tubing 10 contains cross over 24 at its distal end which is used to fluidly connect injection tubing tail joint 26 therewith. Insulated injection tubing 10 is confined within intermediate casing 18 so as to retain heat therein until steam can easily enter injection tubing tail joint 26 located within slotted liner 16 which extends horizontally within oil bearing formation 12 for a distance of at least about 200 to about 400 meters.
A substantially vertical portion of intermediate casing 18 penetrates formation 12 from about 300 to about 400 meters. Of course, as will be understood by those skilled in the art, these distances are formation dependent. Since injection tubing tail joint 26 extends substantially horizontally within slotted liner 16, any heat loss from tail joint 26 will dissipate into formation 12.
Steam travels down insulated injection tubing 10 and uninsulated injection tubing tail joint 26 where it exits into slotted liner 16. Because injection tubing 10 is insulated, heat loss into the vertical portion of the formation is minimized. Steam exits injection tubing tail joint at its far or distal end. Steam circulates within slotted liner 16 and flows into production tubing 20 where it exits formation 12 along with any hydrocarbonaceous fluids or water. Steam is circulated into formation 12 in the manner described for at least about 2 to about 5 years. As will be understood by those skilled in the art, the period of steam circulation is formation dependent. Steam circulation from the formation 12 is controlled by outlet surface valve 30.
While circulating steam into and from formation 12, steam pressure is maintained below the formation or reservoir fracture pressure. This steam pressure will generally be about 450 psi or less, depending, of course, on the formation pressure, which should be greater. Axial pressure exerted on production tubing 20 should be about 200 psi so as steam circulation to the surface. During steam initiation and circulation, an area of formation 12 penetrated by slotted liner 16 is heated by conduction only. The area of the formation from which hydrocarbonaceous fluids oil are derived can comprise heavy or viscous oils, asphalt, or asphaltic materials, for example. Heavy oils are defined as those oils having an API gravity of 19° . or less.
During the circulating and conduction heating period, oil production from production tubing 20 commences. Primary heavy oil production may be obtained by either artificial lift, e.g. by pumping means, or steam lift. If artificial lift is chosen, a production pump is placed on the wellbore assembly and the oil warmed by conduction is produced forcibly from the reservoir. During the artificial lift phase, steam circulation within the wellbore may either be terminated or continued. Oil production rates are anticipated to be higher, if steam circulation is maintained. Again, this points out the importance of the role of conductive heating in this process.
If steam lift is chosen, then the wellbore pressure is controlled by surface outlet valve 30. Wellbore pressure may be reduced to that below reservoir pressure while maintaining steam circulation. In this manner, oil flow from the reservoir 12 through the slotted liner 16 is initiated. Steam circulation provides heat to the reservoir by conduction alone during this process. Steam lift facilitates producing the oil bearing formation during steam circulation. Mechanical difficulties associated with artificial lift and steam circulation are avoided when steam lift is used.
Conduction heating is the main component of the process. Oil production is substantially a result of conductively heating the formation. Steam entry into the formation may take place but is not necessary for oil production.
This conduction heating process has several advantages over steam injection processes. Firstly, a pressure-up phase is not necessary. Secondly, no steam injection into the formation is necessary to initiate oil production. Thus, this process is particularly beneficial in water-sensitive formations, since substantial amounts of water are not produced in the formation. Thirdly, conduction-heated oil flows into the wellbore due to the natural drive of higher formation or reservoir pressure to a lower wellbore pressure. Because of these advantages, a novel, unique method of obtaining initial oil mobility without steam injection from the wellbore into the formation is provided for.
In addition to water-sensitive formations, this method is particularly beneficial when producing heavy oil from a formation containing an aquifer 28 or a bottom water zone below the area being produced as is shown in FIG. 1. This method is beneficial because pressure gradients near the horizontal wellbore are substantially less when heating and producing simultaneously viscous oil from the reservoir. When the near-wellbore area is unheated, the pressure gradients are substantially greater which causes water cones to form earlier in the production cycle. FIG. 4 shows water cone formation at different times near wellbore 8 in reservoir 12. Oil in the reservoir is separated from aquifer or bottom water zone 28 by water/oil interface 32.
Because the pressure gradient is substantially greater in the near-wellbore area when the horizontal well is cold, the water coning effect causes water to break through which leads to an increased water to oil ratio. This increased water ratio causes the production of oil from the formation to become uneconomical at an early stage of production. Calculated pressures around a horizontal wellbore are shown in FIG. 3. As shown there, a heated steady state during simultaneous oil production results in decreased pressure along the wellbore at substantially all radial distances from the wellbore. Calculations of a cold steady state show substantially increased pressures at radial distances up to about 800 feet from the wellbore.
FIG. 4 indicates the effect of a cold steady state upon water coning. As shown in this representation, the peaks and bases of the water cones formed with time are sharper and well-defined relative to wellbore 8 and oil/water interface 32. The bottom water zone or aquifer 28 lies below oil/water interface 32.
As horizontal wellbore 8 is heated, the water coning effect for a selected time interval (t-1) is substantially lessened. This is depicted in FIG. 5. Similar results are shown when wellbore 8 is heated for other selected time intervals, i.e. (t-2 through t-breakthrough). Since the water cones when heating wellbore 8 are substantially lessened and flatter than are possible in a cold steady state (FIG. 4), greater volumes of oil are produced from the formation with decreased volumes of water. Additionally, water breakthrough is delayed when heating wellbore 8 as shown in FIG. 5, while simultaneously producing oil from reservoir 12.
Heating causes a change in the viscosity of oil or hydrocarbonaceous fluids surrounding wellbore 8. Of course, as the reservoir is heated by steam circulation, oil viscosity is decreased at increased distances from the wellbore. This occurrence is graphically illustrated in FIG. 6. Heat also causes a flattening or spreading out of a pressure sink in the near-wellbore region which reduces water coning in a heavy oil viscous oil reservoir underlain by a bottom water zone. Thus, simultaneous heating and producing of a near-wellbore via a horizontal well reduces water coning in a viscous or heavy oil formation during primary oil production.
Many other variations and modifications of this invention as previously set forth may be made without departing from the spirit and scope of this invention as those skilled in the art understand. Such variations and modifications are considered part of this invention and within the purview and scope of the appended claims.
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A method to reduce water coning in viscous oil formations during primary oil production wherein a horizontal wellbore is heated by circulating steam therein thereby heating a radial area near the wellbore. Near wellbore heating alters a pressure profile in the radial area near the wellbore. Reduced inflow pressure gradients near the wellbore flatten out a pressure sink associated with the wellbore. This reduces substantially water coning which allows more oil to be produced before high water production begins.
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CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of U.S. patent application Ser. No. 08/314,707, filed Sep. 29, 1994, now abandoned.
FIELD OF THE INVENTION
This invention relates to the use of thin layer chromatography (TLC) to analyze chemical mixtures.
BACKGROUND OF THE INVENTION
In conventional thin layer chromatography, a glass plate, or a sheet of aluminum or plastic is used as the carrier of a sorption layer of silica or alumina. After placing a spot of the mixture to be analyzed on the plate, the plate is placed in contact with an appropriate solvent which ascends the sorption layer on the plate due to capillary action. This causes the spot representing the mixture to be separated into the components in the mixture in accordance with the solubility of the component in the ascending solvent. Thus, each separated spot represents one of the compounds that make up the mixture. Each spot must then be removed from the plate along with its sorption carrier layer in order to be analyzed. There is at present no simple method to accomplish this removal. Typically, the sorption layers with the separated spots are scraped from the plate and the chemical(s) eluted from the sorption material, Only after this procedure is completed can the structure of the chemicals be determined.
Furthermore, there is no TLC apparatus which can be used in a spectral analysis procedure which does not first require similar scraping and eluting, as described above, before the spectral analysis can be performed.
Accordingly, it is an object of the present invention to provide a TLC apparatus and a simplified method of TLC analysis, wherein the TLC separations are performed and the spectral analysis is accomplished without requiring scraping and/or eluting of the sorption layers.
Other objects will appear hereinafter.
SUMMARY OF THE INVENTION
The invention comprises a method of analysis by infrared spectroscopy using thin layer chromatography (TLC) to separate a mixture into its components. The device for performing TLC comprises a support, e.g. screen, scrim, membrane, grid, mesh (of metal, glass fibers, etc.), preferably a support in the form of a screen, that is substantially opaque to infrared radiation, upon which is deposited a thin layer of any of the known chromatographic sorption materials, e.g. alumina, silica, cellulose, polymeric materials (polyamide, etc.).
Specifically, the method invention comprises the following steps:
(a) forming a slurry by mixing at least one chromatographic material selected from the group consisting of alumina, keisilguhr, attapulgite clay, silica gel, cellulose and polyamide in a suitable inert liquid;
(b) depositing a thin layer of the slurry on a support that is unaffected by the solvent and that is substantially opaque to infrared radiation;
(c) drying the slurry on the support to form a support coated with the dried slurry;
(d) dissolving a mixture of organic compounds to be analyzed in a solvent for the mixture to form a solution;
(e) placing the coated support formed in step (c) vertically in the solution formed in step (a) so that the bottom edge of the coated support is in the solution;
(f) waiting a sufficient time for the solution to rise by capillary action, preferably to the top edge of the support; and then, optionally drying the coated support before
(g) exposing the resulting coated support to infra-red energy at a plurality of positions along the vertical length of the support to provide a plurality of infrared spectra at various levels from the bottom to the top of the support, each of the vertically disposed infrared spectrum representing one of the organic compounds that had been dissolved in the solvent to form the solution in step (d).
Thus, this invention provides a relatively simple method to analyze the components of a chemical mixture after the components have been separated into individual components via thin layer chromatography. In summary, the chromatographic sorption material, such as alumina, is first placed on a screen matrix. The mixture to be analyzed is then "applied" to the coated screen by "developing", i.e. rising via capillary action after being placed in a solvent for such "development". After the separation has occurred, the screen is dried, preferably, rather than merely allowed to dry. The dried screen strip or plate is then placed in the FTIR (Fourier Transform Infra-Red) spectrometer and the spectrum determined at about every 8-10 mm of the height of the plate, starting from the point where the sample mixture was first applied to the screen support. In this fashion, a series of spectra are obtained. For example, if the mixture contained benzoic acid, salicylic acid and biphenyl, the IR spectra of those chemicals would be "read" in that order along the vertical height of the plate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified front view illustration and FIG. 2 is a side view illustration of the apparatus used in the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred device, as shown in FIG. 1, consists of a screen matrix 11 covered with chromatographic sorption material 12 that is prepared as follows:
First, a slurry of aluminum oxide in toluene is prepared by stirring these materials rapidly to form a suspension. Two-three mls of the suspension are then placed on the screen matrix and allowed to dry. The slurry should be spread onto the screen as thinly as possible and the slurry should be nearly transparent when dry. Drying the coated screen usually requires 15-30 minutes at room temperature.
A mixture of organic components is prepared by dissolving 100 mg of benzophenone and 100 mg of benzoic acid in 2 mls of toluene. One drop of this mixture is placed 1/4 inch from the bottom edge of the coated screen. Next, the screen containing the drop of mixture to be analyzed is placed in a beaker containing 1/16 inch of toluene. Capillary action then draws the toluene upward to cover the screen and to cause separation of the components of the mixture being analyzed. The screen may be removed from the beaker when the toluene reaches the top of the screen. The screen containing the separated components is next allowed to dry.
To perform an analysis of the separated components, the screen is placed in an FTIR spectrometer so that the bottom 1/3 of the screen is in the path of the beam of infrared energy. The spectrum of this section of the screen is recorded; the spectrum will be that of benzoic acid. The screen is repositioned to place the top 1/3 of the screen in the path of the beam of infrared energy. Recording a spectrum from this area reveals that of benzophenone.
This method is unique in that the TLC separation and the FTIR analysis of the components of the mixture can be performed on the same device. The screen may be used to analyze any substances for which TLC is normally employed.
The preferred screen has a mesh of about 1-2 millimeter openings, but may range anywhere from as little as an 0.1 millimeter opening to openings of 10 millimeters. The size of the openings must be such that adequate energy is transmitted through the chromatographic coating on the screen to provide a readable IR spectrum. It is recognized that the FTIR spectrometer usually requires passage of from 5 to 40% energy through the screen in order to realize a usable spectrum.
The screen material can comprise any plastic, metal, or glass fiber. The only practical requirement is that the screen not be attacked by the solvents or reagents used in the chromatographic process. In actual practice, stainless steel or fiber glass screens have been found to be most satisfactory.
The thickness of the sorption layer of chromatographic material placed on the screen may be anywhere from 0.01 to about 1.0 millimeter, preferably about 0.1 to 1.0 millimeter.
It is important for easy determination of the spectra of the materials to be analyzed that the screen material used is opaque to infrared radiation. Membrane cells, which are usually composed of either polyethylene or polytetrafluoroethylene membranes, materials which are not opaque to IR radiation, may also be used. However, the spectra of these polymetic materials must be factored into the spectral readings obtained before concluding the analysis.
It is also important that the IR absorbance of the chromatographic material be reliably low. The most transparent of these materials is silica gel. However, aluminum oxide, when applied to a thickness no greater than 1.0 millimeter, is equally useful.
In the earlier description, the separation and analysis of a mixture of benzophenone and benzoic acid in toluene are described using aluminum oxide as the chromatographic material. Another separation and analysis (spectral determination) was performed using a mixture of benzoic acid, salicylic acid and biphenyl in a small volume of toluene. 0.01 milliliter of this mixture was applied to a screen that had been coated with a layer of alumina no more than 1.0 millimeter thick. The coated screen was "developed" using acetone as the solvent. After the screen is fully "developed" by capillary action, the screen is dried and then examined via FTIR spectroscopy. First, the area of the original spot was examined. A spectrum was then determined at intervals of 8 millimeters above the spot. Three spectra were obtained in this manner. The first being identical to that of benzoic acid, the second being that of salicylic acid and the third being that of biphenyl.
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A method for spectral analysis of mixtures is disclosed using thin layer chromatography for separation of the components of the mixture followed by taking FTIR spectroscopic readings along the vertical length of the coated support.
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TECHNICAL FIELD
The present invention relates to a prefabricated self-supporting building structure consisting of a plurality of substantially triangular shaped panels which are interconnected to form roof segments which are easy to erect and to connect together.
BACKGROUND ART
Various prefabricated building structures are known and the majority of these comprise pre-casted or pre-assembled panel structures which are transported to an erection site and assembled. Although many of the component parts of the buildings are pre-fabricated, the erection time can be fairly lengthy and inclement weather conditions can further slow down the erection time as well as expose building materials to rain or snow which sometimes will cause the materials to become damaged. Often, the pre-assembled parts are difficult to transport and the transport vehicle must be operated at slow speed, particularly in a situation where an entire home is prefabricated in two sections. They require long trailer vehicles and special vehicles to warn oncoming traffic of the danger of the wide load on the transport vehicle.
Another disadvantage of prefabricated structures is that they are heavy to manipulate and often require large cranes which are expensive. Many of the prefabricated or other type home or building structures are constructed for permanent installation and cannot be easily dismantled and reassembled on another site. A still further disadvantage of prefabricated structures is that often these are not very structurally sound and can become damaged if exposed to tornadoes or hurricane force winds. A still further disadvantage is that some of these structures are erected directly on a slab of cement which is poured on the ground and therefore are easily exposed to flooding with resulting serious damage. Some of these are also not well insulated or resistant to insect infestation such as by termites. Often, their construction causes condensation to set into the structure which can also affect building materials. Still further prefabricated building structures require expensive foundations made of concrete thereby increasing the cost of the prefabricated structure.
Typical examples of prefabricated structures can be found in U.S. Pat. Nos. 5,960,593; 5,950,374; 5,758,461; 4,660,332; 5,904,005; 5,921,047; 4,741,133; 4,912,891; 5,765,316; 5,797,224 and 5,461,832.
SUMMARY OF INVENTION
It is a feature of the present invention to provide a prefabricated self-supporting building structure and a method of erecting such building structure and which substantially overcomes the above-mentioned disadvantages of the prior art.
According to the above features, from a broad aspect, the present invention provides a prefabricated, self-supporting, building structure which is comprised of a plurality of substantially triangular shaped panels. Each of the panels has a front edge, a straight top edge, a straight hypotenuse edge and a junction point at an intersecting end of the hypotenuse edge and the front edge. The panels are connected in juxtaposed pairs by a hinge connection means which interconnects the top edge of each juxtaposed pair of panels to form a collapsible roof segment. There are four roof segments interconnected together in side-by-side relationship at right angles to one another to form the building structure. Each panel of the juxtaposed pairs of panels are connected along their straight hypotenuse edge by a further hinge connection means to the straight hypotenuse edge of a panel of an adjacent roof segment. Attachment means is provided at the junction point of the panels for securing the roof segments in elevated position on a support means. Connector means are provided at a forward end of the top edge of at least one panel of two of the roof segments interconnected back-to-back for attachment to pulling means. The pulling means causes the panel segments to be erected to form a roof structure anchored at the attachment means.
The method consists essentially of connecting the attachment means at the junction point of the roof segments of two panel sections to a support means and connecting a pulling cable to the connector means at a forward end of the top edge of the roof segment of two panel sections. The two panel sections are erected back-to-back by pulling the cable with the further panels of each of the two panel sections having their straight top edge at right angles to the straight top edge of its associated roof segment. Adjacent ones of the top edge of the further panels are secured together by ridge capping connection means whereby to secure the two panel sections together back-to-back and to form a building structure having four roof segments disposed at right angles to one another.
Floor segments can also be secured under the building structure and connected to the roof segments.
BRIEF DESCRIPTION OF DRAWINGS
A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which:
FIG. 1 is a perspective view showing the panels connected together to form a roof segment and one of two pre-assembled panel sections;
FIG. 2 is a perspective view showing the prefabricated, self-supporting building structure of the present invention in an erected secured position;
FIG. 3 is a section view showing a typical construction of the panels;
FIG. 4 is a fragmented view, partly in section, showing the roof structure of the present invention erected and segmented internally to form a building structure having two floor structures and anchored into the soil by ground anchors;
FIG. 5A is a perspective view showing a typical construction of a securement bracket secured to the junction point at an intersecting end of the hypotenuse edge and the front edge of the panel;
FIG. 5B is a perspective view of a support wall anchor secured to a foundation or pile;
FIG. 6 is a perspective view showing the prefabricated roof structure of the present invention used in the construction of a multi-tenant building structure;
FIGS. 7A to 7 J are perspective illustrations showing the sequence of erecting the building structure of the present invention starting from juxtaposed, pre-assembled panels assembled together to form one of two panel sections and illustrating the steps in the assembly of the building structure; and
FIG. 8 is a typical floor plan view of one of the floors of the building structure.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings and more particularly to FIG. 1, there is shown generally at 10 a building structure segment 11 pre-assembled with the substantially triangular shaped panels 12 of the present invention whereby to form the pre-assembled panel sections, two of which are required to be interconnected to erect the complete building frame structure of the present invention, as shown at 13 in FIG. 2 . The substantially triangular shaped panels 12 , as shown in FIG. 3, may be formed of steel roof cladding 14 on an outer surface thereof and a steel deck cladding 15 on an inner surface thereof. A foam core 16 is injected between the claddings 14 and 15 to form an insulated panel structure. The foam 16 may be a polyisocyanurate or a polyurethane foam or any other insulating rigid foam material. Accordingly, these panels are fairly light and easy to manipulate while the corrugation in these panels provide excellent structural properties and the foam core provides good structural and insulating properties.
As shown in FIG. 1, each of the panels 12 has a front edge 17 , a straight top edge 18 and a straight hypotenuse edge 19 . A junction point 20 is formed at an intersecting end of the hypotenuse edge 19 and the front edge 17 . Attachment means in the form of securing brackets 21 are connected to adjacent panels 12 and 12 ′ at the junction point 20 whereby to secure the erected structure, as shown in FIG. 2, to a support means 22 , herein a ground anchor 23 . These ground anchors 23 are better illustrated in FIG. 4, and as can be seen, they consist of a screw-type anchor rod 23 which is driven into the ground 24 and which resists pulling forces applied on the building structure 25 formed with the roof segment structures 13 , shown in FIG. 2 of the present invention.
Referring again to FIG. 1, there is shown the pre-assembled panel section 10 which consists of a roof segment 26 which is formed by connecting in juxtaposed pairs two panels 12 ′ and 12 ″ by hinge connection means, which may be adhesively or mechanically secured to opposed edge sections of the opposed panels 12 ′ and 12 ″ along their straight top edge 18 or opposed hypotenuse edges 19 . Hinge plates 18 ′ are secured to opposed inner edge surfaces of the top edge 18 of the panels. After erection, a ridge cap 27 may be secured externally over the top edge 18 . Various other forms of hinge connection means could be substituted and it is within the ambit of the present invention to cover any other obvious hinge structures.
The pre-assembled panel section 10 also comprises a panel 12 ′″ of an adjacent roof segment 26 ′, see FIG. 2, to be formed. These panels 12 ′″ are connected respectively to the juxtaposed panels 12 ′ and 12 ″ by a further hinge connection means herein constituted by a further flexible adhesive tape 27 ′.
With specific reference to FIG. 7A, it can be seen that the panels 12 ′″ may be folded on their associated respective panels 12 ′ and 12 ″ and also the panels 12 ′ and 12 ″ may be folded upon themselves to form a stack 30 of juxtaposed folded substantially triangular shaped panels, making them easy to transport.
As shown more clearly in FIG. 4, anchor means in the form of steel anchors 31 may be secured to the panels 12 and 12 ′ adjacent their straight top edge 18 and forwardly of the roof segment 26 at its forward end, that is to say near the front edge 17 of the triangular panels 12 . As shown in FIG. 1, a cable 32 is secured to the anchors 31 and to a winch 33 to apply a forward pulling force in the direction of arrow 34 whereby to erect the pre-assembled panel section 10 on the ground anchors 22 after the securement brackets 21 are pivotally secured to the ground anchors. Further connectors 35 are also secured adjacent the top edge 18 of the adjacent panels 12 ′″ whereby to secure a further spacer cable 36 of predetermined length whereby when the pre-assembled panel section 10 is erected, these side panels 12 ′″ will be maintained hinged out with their top edge 18 aligned and extending substantially transverse to the top edge 18 of the roof segment 26 . A further spacer cable 37 of predetermined length is also attached between the securement brackets 21 at the junction point 20 of the adjacent panels 12 ′ and 12 ″ to limit the spacing between these panels when in an open position.
In order to construct the building structure as shown in FIG. 2, there is required two such pre-assembled panel sections 10 and these are erected back-to-back, as illustrated in FIGS. 7I and 7J and these are erected simultaneously in a similar fashion. By the pivoting action of the pre-assembled panel sections 10 which are positioned back-to-back and by movement of the winch 33 , these sections can be brought together with the top edges 18 of the adjacent panels 12 ′″ in substantially perfect alignment. The ridge cap 27 , or other type connection, is then applied to the top edge 18 of adjacent panels 12 ′″ of the two pre-assembled panel sections 10 placed back-to-back and this completes the securement of the structure. Internal braces (not shown) may also be secured to the inner face of the roof structure to solidify its connections should this building structure be utilized as a canopy, as shown in FIG. 2, for another structure to be positioned thereunder or for any other purpose.
As shown in FIGS. 4 and 6, the building structure is herein shown formed as a residential building and prefabricated floor structures 40 are brought into position and secured to the inner surface of the panels 12 by suitable anchor means (not shown). Two such floor structures may be secured to constitute a dwelling having two floors and, of course, if this roof structure is fairly large, it can accommodate four dwellings, each of which is associated with one of the roof segments 26 , there being four roof segments in this building structure with the axes of their top edge extending transverse to one another. Such structures would be convenient to construct low cost housing or temporary housing as the structure can be easily disassembled and transported elsewhere. It is also pointed out that such structures are very resistant to earthquakes, hurricanes, tornadoes, termites, the formation of condensation, etc. Also, because the lower floor may be used as a parking space, as shown at 41 in FIG. 6, the main floor is elevated sufficiently high so that the building structure can resist flooding. The lower section or the entire triangular panels could also be constructed in a waterproof fashion or at least the lower ends thereof below the main floor 40 ′, and dependent on the geographic location of the structure.
Referring to FIGS. 5A and 5B, there is shown a typical construction of a securement bracket 21 and an anchor bracket 50 . The securement bracket 21 may be in the form of a triangular shaped steel plate 51 having holes 52 therein to receive fasteners to secure it to the panel at the junction point area 20 thereof as shown in FIG. 1 . This area may also be reinforced. A connecting flange 53 extends forwardly of the bracket 51 and extends at a predetermined angle so that adjacent brackets 21 of adjacent panels can be secured to the projecting tongue 54 of the anchor bracket 50 by extending on both sides of the tongue and by securing a bolt 55 through the flanges 53 and the tongue 54 . This constitutes a pivotal connection. The anchor bracket 50 also has a base plate 57 provided with holes 58 to secure same to corners of a foundation wall 59 or to the attachment end 22 of the anchor rods 23 . Numerous other forms of brackets and anchors can be constructed to secure the roof segments of the building structure. Also, when the structure is erected on a foundation 59 as shown in FIG. 5B, the roof structure can be erected elevated from the ground surface. The collapsed panels would be placed on a floor flush with the foundation and tilted up on its convectors.
FIG. 8 shows a typical floor plan for a floor of a two-story dwelling and the illustration is self-explanatory. It is also pointed out, with further reference to FIG. 6, that the front edge 17 of the roof segments need not be straight but could have a forward projection in a top portion thereof extending at a different angle whereby to constitute an overhanged roof section, as illustrated by phantom lines 60 in FIG. 8 that project over a balcony 61 which is preformed with the prefabricated floor 40 to substantially shield it from rain or sun.
With reference to FIGS. 7A to 7 J, there will be described the manner in which the roof structure of the present invention is erected. A first stack 30 of assembled panels constituting a first pre-assembled panel section 10 is brought on a site 62 where the roof structure is to be assembled. The panels are lifted vertically and separated as shown in FIG. 7B until the junction points 22 are fully extended as delimited by the base spacer cable 37 , as shown in FIG. 7 C. This positioning of the panels can be effected by a small group of people. As shown in FIGS. 7B and 7C, once the roof segment starts separating, it then supports itself. The side panels 12 ′″ are then folded out to each side of the roof segment 26 and laid on the ground. The spacer cable 36 maintains the straight top end 18 of the side panels 12 ′″ extending substantially perpendicular to the top end 18 of the roof segment 26 and in substantial axial alignment with the top end 18 of the adjacent side panel 12 ′″.
As shown in FIG. 7E, the pulling cable 32 is then secured to the steel anchor 31 and to a winch 33 . However, before doing so, the securement brackets 21 have been attached to the anchor brackets 50 so as to provide a pivotal connection. The winch is actuated to pull the panels to cause them to rise in the fashion as shown in FIGS. 7F to 7 H. A second stack of panels are positioned behind the raised pre-assembled panel section 10 and the same procedure is repeated by raising the other pre-assembled panel section 101 , as shown in FIG. 7I, by forward movement of another winch 33 ′. The winches are maneuvered to bring the top edge of the side panels 12 ′″ of the back-to-back pre-assembled panel sections 10 and 101 in substantial alignment with one another. The top edges of adjacent panels are then secured by one or more ridge caps 27 , as previously described, to complete the structure. The cables can then be removed. Typically, such a roof structure can be erected very quickly and within a few hours.
It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiments described herein, provided such modifications fall within the scope of the appended claims.
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A prefabricated self-supporting building structure and method of construction is described. The building structure comprises a plurality of substantially triangular shaped panels which are interconnected to one another by a hinge connector and along certain edges thereof whereby to form collapsible roof segments. There are four roof segments in the building structure. The triangular shaped panels are interconnected to form two pre-assembled collapsible panel sections each incorporating a pre-assembled roof segment and panel sections for adjacent roof segments. These two pre-assembled panel sections are erected by simple cable attachments which may be secured to a vehicle and these are interconnected back-to-back. The roof segments are also secured by brackets at their junction points of the panels for securing the roof segments in elevated position on supports. The panels of the two pre-assembled panel sections are also foldable one on top of the other in juxtaposition and therefore the entire roof structure is easy to transport and easy to erect on site.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application Ser. No. 62/037,301, filed Aug. 14, 2014, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The human external jugular vein (EJV) is a large vein used in pre-hospital medicine for venous access when the emergency medical technician (EMT) is unable to find another peripheral vein. It may also be used in an emergency or non-emergency setting where another peripheral vein cannot be located. It may be used in an unresponsive or an alert patient.
[0004] 2. Description of the Related Art
SUMMARY OF THE INVENTION
[0005] Inserting an IV for Intravenous therapy (IV or iv therapy in short) is the infusion of liquid substances directly into a vein. Inserting an IV into the EJ vein may be difficult due to the patient's body habit's or build or during an emergency, such as a cardiac arrest, hemorrhage or shock.
[0006] Often the patient is placed in the Trendelenburg position where the body is laid flat on the back (supine position) with the feet higher than the head by 15-30 degrees, so the head is down. The patient is instructed to “bear down” or perform the Valsalva maneuver in an effort to dilate the vein. The Valsalva maneuver is a moderately forceful attempted exhalation against a closed airway, usually done by closing one's mouth, pinching one's nose shut while pressing out as if blowing up a balloon. This may not be indicated or may even be harmful in certain cases, such as congestive heart failure. Further the patient may not be cooperative or able to understand the instructions. Currently the only other way to dilate the EJ vein is with thumb pressure which makes the process of IV insertion technically more difficult and time consuming.
[0007] The cephalic vein (ECV), an external type vein, passing across the shoulder anterior aspect of the shoulder may also be used for IV therapy in some situations.
[0008] The IV procedure can be done by EMTs (Emergency Medical Technician) at the scene of an accident, or by a nurse or by a doctor in an office or hospital setting.
[0009] What may be needed is a device that can quickly and easily placed on the patients neck without choking to dilate the EJ vein to allow easy insertion of an IV needle.
[0010] What may be needed is a device that can quickly and easily placed on the shoulder at about the mid-clavicular line or more proximal to dilate the CV vein to allow easy insertion of an IV needle.
[0011] What may be needed is a device that may be used to apply unilateral or bilateral pressure to the EJ vein or CV vein as needed.
[0012] Sometimes additional pressure may needed for some patients to increase dilation and what may be needed is a device that can increase pressure after application to a maximal pressure of about 90 mmHG, under a pressure that may cause carotid artery compression when on the neck.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows the structure of the human throat showing location of the external jugular vein (EV).
[0014] FIG. 2 is a cross section view of the neck showing the location of the external jugular vein.
[0015] FIG. 3 depicts an external jugular vein device positioned to apply pressure.
[0016] FIGS. 4 and 5 show cross-sections of spring and clamp members of FIG. 3 .
[0017] FIG. 6 depicts another external jugular vein u-shaped device positioned to apply pressure.
[0018] FIG. 7 shows the external jugular vein device of FIG. 6 compressing the external jugular veins.
[0019] FIG. 8 shows a frontal neck view of the clamp 300 when applied.
[0020] FIG. 9 shows the clamp 300 when not applied to the neck.
[0021] FIG. 10 depicts a clamp member 620 aligned at an angle with respect to a clamp tip 630 .
[0022] FIGS. 11A and 11B show a circular pad type clamp member 710 .
[0023] FIGS. 12A and 12B shows a tip flattened to for a clamp member.
[0024] FIG. 13 illustrates a loop shaped clamp member.
[0025] FIG. 14 shows the veins in the shoulder and arm.
[0026] FIG. 15 shows a C-tourniquet in relation to the veins of the shoulder.
[0027] FIG. 16 shows the C-Tourniquet or clamp on the shoulder.
[0028] FIG. 17A through 17D depict an embodiment with a single sided clam with a clamp member 956 on one side.
[0029] FIG. 18A through 18D show an embodiment with inflatable clamp members.
[0030] FIG. 19 depicts a C-tourniquet which is wider in the clamp area and where the clamp area is longer for better compression and adaptability to neck size variation.
[0031] FIG. 20 shows a cross-section of FIG. 19 .
[0032] FIG. 21 shows another embodiment that is applied from the back of the neck.
[0033] FIG. 22 shows the C-tourniquet of FIG. 21 when not applied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0034] Below and in conjunction with the figures will be described an external C-tourniquet or C-clamp that may be used to put pressure on human body veins, such as the external jugular (EJ) vein and the cephalic vein. When applied to the EJ vein the C-tourniquet does not choke the patient and leaves room for quick and easy IV therapy (or access) via the EJ vein.
[0035] As shown in FIG. 1 , the neck 100 includes two external jugular veins 110 and 120 located on each side of the neck 100 and running vertically between the jaw and the collar bone. The veins 110 and 120 , as shown in FIG. 2 , are positioned just under the skin 200 of the neck 100 .
[0036] FIG. 3 depicts a first embodiment of the C-tourniquet 300 , it may preferably be a single piece structure made of plastic or metal as discussed below. The device 300 may have a spring member 302 and two clamp members 304 and 306 . As can be seen, the clamp members 304 and 306 apply pressure to the EJ veins 308 and 310 . The cross-section A′-A of the spring member 302 and that cross-section B′-B of one of the clamp members 306 of the device 300 are shown in FIGS. 4 and 5 .
[0037] As can be seen the cross-section of the spring member 302 may be round as depicted in FIG. 4 but may be oval, rectangular or some other shape. The spring member 302 imparts a closing force to the clamp members 302 and 304 to push them toward each other.
[0038] The cross-section of the clamp member 306 , as depicted in FIG. 5 may be a flattened oval where one of the “flat” and “edge” sides confronts the neck. The spring member when it joins the clamp member is shown in dashed lines. The clamp members may have some other shape, such as round, oval, rectangular, etc. such that a non-penetrating shape is provided that can apply pressure to the veins without causing undue discomfort to the patient.
[0039] Another embodiment of the jugular vein tourniquet or clamp 320 , as shown in FIG. 6 , includes a spring member 322 and at least one clamp member where two clamp members 324 and 326 are shown. The clamp 320 may be preferably of disposable plastic as one piece, which could be made by injection molding. The spring member 312 may be of a circular cross section, although it may be another shape, such as an oval or rectangle, and may be tapered from the center 340 to the tips 350 and 360 to provide a variable spring force as the clamp 320 is opened. The radius of the spring member may such that the spring member reaches across the neck 100 . Each of the clamp members 324 and 326 is shown with a circular convex type shape although the shape and size may be more like the pad of a finger, such as the thumb, with a curved center part having a low curvature like the finger pad and the ends with a higher curvature like the sides of the finger. The clamp members 324 and 326 may have a rectangular cross section where the side 370 toward the skin may have a surface that prevents slipping, such as a cross-hatched relief pattern surface. Although the cross-section of the clamp member may be rectangular in cross-section, the side of the clamp member away from the skin may be flat or curved.
[0040] During application of the clamp or C-tourniquet 300 / 320 , where 320 of FIG. 6 will be used as an example, the user may place one of the clamp members, such as 326 , on the skin over one of the veins, such as vein 110 . The spring member 312 is then stretched against it's spring force and the other clamp member 330 may be positioned on the skin over the other vein 120 . The spring force of the clamp member 330 may be released and the clamp members 320 and 330 compress the part of the neck 100 where the vein 110 and 120 are located closing the veins.
[0041] FIG. 6 , with some exaggeration for illustration purposes, shows a u-shaped clamp or tourniquet 320 compressing and closing the veins 110 and 120 . Once the veins are closed they dilate due to the increased blood pressure on the upstream side of the clamp. The user can then use both hands as needed to cannulate the patient via one of the dilated veins.
[0042] FIG. 7 depicts the device of FIG. 6 as applied to the neck 100 showing the veins 110 and 120 compressed shut, which will close the veins to dilate them.
[0043] The clamp may be removed by pulling the spring member 310 away from the neck 100 after one of the veins has been cannulated or accessed.
[0044] The size of human necks vary from small, such as an infant, to large in an adult. It preferable that the clamp or tourniquet 300 (or 320 ) have several sizes, such as small, medium and large.
[0045] As shown in FIG. 8 , the clamp 300 and clamp members 320 and 330 are positioned to compress the lateral aspects of the neck 100 . The clamp 300 may be positioned where the vein superficially passes at the base of the neck 100 . The clamp or C-tourniquet may be positioned close to the collar bone
[0046] FIG. 9 shows the C-tourniquet or clamp 300 when not applied to a patient. As can be seen the device 300 is U-shaped or C-shaped when the spring member 310 is not under expansion tension.
[0047] FIGS. 6 and 7 shows the clamp members 320 and 330 with a cup axis somewhat aligned with the direction of the direction of the tips 350 and 360 . FIG. 10 , depicts an alternate embodiment where the cup 610 of the clamp member 620 may be aligned to the side so that it faces the neck 100 and may be at an angle with respect to the tip 630 .
[0048] FIGS. 11A and 11B show views of another embodiment where the clamp member 710 may be like a miniature padded ear headphone and has an aspect with respect of the tip 720 like in FIG. 10 . The clamp member 710 is shown as circular, but may be some other shape, such as oval or rectangular.
[0049] FIGS. 12 and 12B show a further embodiment where the tip of the clamp member 810 may be a flattened portion of the tip 820 .
[0050] FIG. 13 shows a tear drop shaped clamp member 910 at the end of a tip 920 where the clamp member 910 may be a plastic loop with an open space 930 in the center.
[0051] The clamp member can also be the end of a round or oval cross-section tip as it tapers to an end so that it occupies as little space of the neck 100 as possible. In addition the clamp need not be tapered from the center 340 to the tips 350 and 360 but may be of a constant cross-section.
[0052] Although the clamp 300 has been described with respect to use with the external jugular vein, it can also be used with the cephalic vein which runs across the front of the shoulder to allow venous access and may be threaded into the superior vena cava or central venous circulation. This may be done using the EV or CV.
[0053] FIG. 14 depicts the veins of the shoulder and upper arm and, in particular, the cephalic vein 950 . As shown in FIG. 15 , the C-tourniquet 300 / 320 may be applied to across the shoulder 952 with the dashed lines representing the part of the device on the back side of the shoulder. FIG. 16 shows how this position of the C-tourniquet or claim 330 / 320 may appear without the veins being shown as applied to a shoulder 952 .
[0054] FIG. 17 depicts an embodiment with a single sided clam with a clamp member 956 on one side.
[0055] FIG. 18 shows an embodiments with inflatable clamp members 962 and 964 where the members can be inflated via air passages 966 and 968 using a finger operated pump 970 having a check valve.
[0056] FIG. 19 shows an embodiment in which the clamp members, such as 984 , have been extended up the arms of the C-tourniquet. This allows the device to adapt to variations in neck size and location of the EJ and CV between patients. The device also allows for bilateral compression of the EJ veins.
[0057] FIG. 20 shows a cross-section from FIG. 19 viewed from the end of one arm. As can be seen the clamp member 984 has a flat aspect where the rod shape of the spring member 982 has been compressed. The rod has a round aspect and could be oval or rectangular.
[0058] FIG. 21 depicts a neck 990 where an embodiment of the C-tourniquet or clamp 992 may applied from the back 994 . This embodiment has arms 994 and 996 that are bent toward the neck 990 and may have clamp members of the variations previously discussed, such as in FIG. 19 .
[0059] FIG. 22 shows a shape the embodiment of FIG. 21 where the arms 994 and 996 are bent inward.
[0060] Although the C-clamp or C-tourniquet has been described as being made of injection molded plastic, it could be made of other materials that can provide a s spring force and tend to grip the neck, such as wire, resin reinforced paper, etc. as well as being made by another process, such as raise in the temperature of a plastic rod, using a heat source, such as a heat gun, until it is softens and can be formed, and then forming the clamp around an appropriately shaped mold. The clamp members have been generally been described as made of plastic so that they can be integrally formed with the spring member, however, the clamp members may be of another material, such as a foam or fabric pad. The surface of the clamp member may be roughened or corrugated or flat.
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A blood vessel compression device including a C-shaped spring and a clamp at an end of the spring to compress a blood vessel. The clamp may have a flat shaped cross section or spatulate cross section with an edge where the edge confronts a blood vessel to compress it. The clamp may have a channel and a sac inflatable with air to compress the blood vessel. The device may be positioned on body to clamp an external jugular vein or cephalic vein for cannula insertion. The C-shaped spring may be spaced from a front of the neck to not compress a windpipe of the neck.
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This invention relates to an electrosurgical instrument for treatment of glaucoma and, in particular, to an electrosurgical electrode for relieving pain and slowing progression of the disease of glaucoma, especially end-stage glaucoma, and to the procedure for treating glaucoma with electrosurgery.
BACKGROUND OF THE INVENTION
Glaucoma is an eye disease characterized by increased intraocular pressure, which eventually causes degeneration in the optic nerve head. In its end-stage, it is also extremely painful. One known surgical procedure uses an expensive laser to effect entry into the suprachoroidal space to relieve the pressure.
SUMMARY OF THE INVENTION
An object of the invention is an improved treatment for glaucoma using an electrosurgical instrument.
We have invented a novel electrode for use in an electrosurgical glaucoma procedure. This electrosurgical procedure using our novel electrode enables physicians to offer to patients a treatment for relieving pain and possibly slowing the disease that is efficiently performed, easily learned and thus performed at a significantly reduced cost, with less tissue damage compared to procedures done heretofore, and, most important, with better control over the depth of the treatment.
The procedure is based on forming an appropriate incision to expose the choroid and relieve the intraocular pressure, followed by electrosurgical coagulation using our novel electrode to accomplish direct cyclocoagulation. To this end, the electrode of the invention comprises a flat, thin, slightly-flexible electrically-conductive member coated with an electrically-insulating coating over all but a small exposed area at the surface of the electrode tip. With this novel shape, it becomes possible to effect coagulation where desired in a relatively simple manner. It should be recognized that in advanced glaucoma, the principal goal is pain relief with small hope of improved vision, and the treatment described with the electrosurgical electrode of the invention offers a simple inexpensive treatment.
The active exposed tip is supported by structure that is completely electrically-insulated to avoid damage to surrounding tissue, and to allow the physician to use these inactive insulated parts to help position and guide the active tip, which is the only part capable of treating tissue, during the surgical procedure.
The electrosurgical procedure has the important advantage of coagulating the cut tissue causing minimum bleeding. It is preferred that the electrosurgical currents used be above 2 MHZ, and preferably above 3 MHZ. At these high frequencies, commonly referred to as radiosurgery, the action is limited to the exposed tip of the electrode, which is primarily responsible for only small lateral heat spread and thus less damage to neighboring cell layers.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention, like reference numerals or letters signifying the same or similar components.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a plan view of one form of electrosurgical instrument in accordance with the invention, before manufacture completion;
FIGS. 2 and 3 are plan views of opposite sides of the completed electrosurgical instrument in accordance with the invention shown connected to electrosurgical apparatus;
FIGS. 4 and 4A are perspective views showing how the electrosurgical instrument according to the invention can be used in glaucoma treatment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 2 and 3 illustrate a preferred form of the novel electrosurgical instrument 10 of the invention. It comprises an elongated conventional handpiece 12 (only the collet end is shown in phantom) of electrically-insulating material having a central electrically-conductive tube or conductor (not shown) extending throughout its length and connected at its end to a cable 16 which is connected in the conventional manner to conventional electrosurgical apparatus 18. As an example only, the electrosurgical apparatus can be model AAOP Surgitron FFPF available from Ellman International, Inches. of Hewlett, New York. The Ellman equipment is preferred due to its high operating frequency, typically above 2 MHZ, preferably above 3 MHZ. This particular apparatus provides electrosurgical currents at 3.8 MHZ.
At the opposite end of the handpiece 12 is mounted the electrosurgical electrode 10 which comprises an electrically-conductive straight axial brass or bronze rod 22 which is exposed at the right end for being received in the handpiece collet 12 electrically connected to the electrically-conductive cable 16. At the left end, the rod 22 is flattened to form a thin flat slightly-flexible strip 24. The distal end of the electrode comprises a rounded tip 26. The center region is coated on both sides with an electrically-insulating coating 28, for example of rubber or plastic, which may be of any desired thickness. The left end is coated with a very thin electrically-insulating coating 30 of, for example, baked "Teflon". For ease of understanding, the coatings are shown hatched in the plan views of FIGS. 1-3.
FIG. 1 shows the electrode 10 after the thicker coating 28 is applied but before the thinner coating 30 is applied, which is shown in FIGS. 2 and 3. The latter are plan views of opposite sides of the completed electrode. As will be noted, on the side shown in FIG. 3, the electrically-insulating coating 30 extends the full length from the thicker coating 28 to the rounded tip 26. On the opposite side, shown in FIG. 2, the coating extends only part of the distance, leaving exposed and thus electrically active a small surface region 32 adjacent the rounded tip 26 on only one side of the flat electrode. In addition, on the fully coated side shown in FIG. 3, depth marks 34 are provided at uniform intervals of, for example, 3 mm apart.
For illustrative purposes, the thickness (the dimension perpendicular to the plane of the drawing) of the flat electrode 10 at the small surface region 32, including the coating 30, is about 0.005-0.009 inches, preferably about 0.006 inches. The width (the vertical dimension in the plane of the drawing) of the electrode 10, including the coating 30, is about 0.07-0.09 inches, preferably about 0.078 inches. The overall length (the horizontal dimension in the plane of the drawing) of the electrode 10 is about 2.25 inches. The length 40 is about 0.8 inches. The more important dimensions are that of the thinly coated left end of the electrode 10. The length dimension 42 is about 0.6-0.9 inches, preferably about 0.783 inches, and the length dimensions 44 and 46 are, respectively, about 0.6-0.7 inches, preferably about 0.63 inches, and about 0.1-0.2 inches, preferably about 0.157 inches. The electrical insulation of the thinner coating 30 has a thickness in the range of about 0.002-0.008 inches. For the examples given, the length 46 of the bare part of the working end 24 is approximately 1/10-1/3 of the full length 42.
The actual procedure is as follows. After the usual local anesthesia, tractors are applied to expose the patient's eye, and an incision made along the 12 o'clock meridian shown at 50 in FIG. 4. The incision was carried down to expose the choroid. The electrosurgical apparatus previously identified was set at a power setting of "6", using the partly rectified waveform. The electrode in the handpiece 12 was then inserted into the scleral incision over the ciliary body with the exposed end 32 applied directly to the outer surface of the ciliary body and facing down leaving the back side shown in FIG. 3 visible to the surgeon. At the first mark 34, the apparatus was energized for about 1 second and then shut off, then the electrode was advanced 3 mm into the incision to the second mark 34 and the apparatus again reenergized for 1 second, and the process repeated until the final mark was reached. At that point, the electrode was retracted in 3 mm steps, each time being energized for about 1 second as each mark was reached until the electrode was completely removed. The total depth of treatment was about 18 mm, during which when advancing and retracting the energized electrode introduced radiofrequency currents via the exposed tip 32 at the contacted tissue causing coagulation of blood vessels severed during the incision. Post operative treatment was conventional. Timing the electrosurgical burns as evenly as possible was found desirable. The merit of the treatment is that, by applying the thin electrode with its exposed small surface region directly to the outer surface of the ciliary body in the suprachoroidal space, coagulation of the choroidal tissue without affecting the sclera can easily be achieved with a relatively inexpensive instrument.
The rounded tip 26 offers the advantage of making it easier to get into the scleral wound, and the marks 34 on the back side visible to the physician provide an easy means to determine how deep the electrode has penetrated. The electrode substrate 24 of bendable brass allows the physician to slightly curve the electrode (perpendicular to its plane) as needed for greater control over the penetration angle. Also connected to the electrosurgical apparatus 18 is the usual indifferent plate (not shown) which during use is in contact with the patient's body. When the electrosurgical apparatus 18 is energized, high frequency electrosurgical currents are generated which are coupled by way of the cable 16 and electrically-conductive rod 22 to the active surface region 32. The physician, in the usual way, holds the handpiece 12 while applying the active working end of the electrode to the desired area of the patient to be treated. The handpiece 12 is completely electrically-insulated. The insulating coatings 28 and 30 are essential to prevent accidental burning or other tissue damage by the sides of the electrode as the instrument is manipulated.
For completeness' sake, attention is directed to U.S. Pat. No. 4,517,975 which describes an electrosurgical electrode for nail matrisectomy. The electrode comprises a short spade-shaped end with one side completely covered with an electrically-insulating coating. The active end is less than about 1/2 inches as it need be inserted only a short distance under the nail. Moreover, the entire bottom surface is exposed and thus active, and no markings on the back side are needed since the penetration depth is less critical and the burning does not occur at spaced intervals. In the present invention, the depth penetration includes the entire length 42, whereas only a small part 32 of the front side is uncoated, so that during most of the procedure, both the fully coated back side and the partially coated front side are foreclosed from supplying electrosurgical currents to the adjacent tissue. Moreover, the markings on the back side are helpful in assisting the physician during the step-by-step electrode advancement and retraction from the patient's tissue
While the invention has been described in connection with preferred embodiments, it will be understood that modifications thereof within the principles outlined above will be evident to those skilled in the art and thus the invention is not limited to the preferred embodiments but is intended to encompass such modifications.
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A procedure for treating glaucoma is based on forming an appropriate incision to expose the choroid and relieve the intraocular pressure, followed by electrosurgical coagulation using a novel electrode to accomplish direct cyclocoagulation. To this end, the electrode of the invention comprises a flat, thin, slightly-flexible electrically-conductive member coated with an electrically-insulating coating over all but a small exposed area at one surface of the electrode tip. With this novel shape, it becomes possible to effect coagulation where desired in a relatively simple manner.
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This Application is a divisional application of application Ser. No. 07/079,855, filed 7/30/87 now being allowed.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process and the resultant composition whereby a lower alkene monomer is converted to a lower alkene polymer through the use of unique reaction conditions and catalyst system. The lower alkene polymers so obtained have a high degree of mono-unsaturation content and are highly reactive in various reactions.
2. Description of the Art Practices
It is known from U.S. Pat. No. 2,816,944 issued Dec. 17, 1957 to Muessig et al that olefinic polymers ranging in a carbon content of from 12 to 50 carbon atoms obtained from olefins having 5 to 25 carbon atoms may be prepared by using boron trifluoride with phosphoric acid. It is generally disclosed by Muessig et al that the polymerization may take place using kieselguhr, and is conveniently conducted at a temperature of 35° C. to 60° C.
Serniuk in U.S. Pat. No. 2,810,774 issued Oct. 22, 1957 describes an olefin polymerization catalyst system comprising boron trifluoride and acids of phosphorus. It is also disclosed by Serniuk that various absorbents such as aluminum silicates, kieselguhr, Fuller's earth, clays and silica gel may be employed as a support system for the catalyst. The Serniuk reference describes reaction temperatures of 77° F. (24° C.) to 212° F. (100° C.) during the polymerization. The olefins of Serniuk include a mixed propylene-butylene system having an active content of about 40% olefins.
U.S. Pat. No. 2,976,338 issued Mar. 21, 1961 to Thomas discloses a catalyst system comprising boron trifluoride and phosphoric acid as being too active for polymerizing olefins because of the rapid evolution of heat. It is disclosed that the boron trifluoride of Thomas may be modified through the inclusion of a potassium acid fluoride salt to give an acceptable product. The olefins employed by Thomas include from 5 to 15 carbon olefins for use in obtaining polymers containing from 10 to 30 carbon atoms. The reaction temperatures of the Thomas patent are generally in range of 32° F. (0° C.) to 212° F. (100° C.), preferably from 100° F. (38° C.) to 160° F. (71° C.).
It is known from the U.S. Pat. No. 2,416,106 issued Feb. 18, 1947 to Linn et al that olefins may be polymerized through the combination of boron fluoride and an acid fluoride metal. U.S. Pat. No. 2,585,867 to Sparks et al issued Feb. 12, 1952 describes the production of high molecular weight polymers from monomers using a boron trifluoride catalyst system with reaction temperatures from -40° C. to -103° C. In particular, Sparks is concerned with the reaction of mono-olefins with di-olefins.
Blewett in U.S. Pat. No. 4,469,910 issued Sept. 4, 1984 describes a process whereby a dimer fraction is reacted in an oligomerization process with an alpha-olefin in the presence of a phosphoric acid- modified boron tri-fluoride catalyst system. The Blewett reference is particularly concerned with the use of 6 to 12 carbon dimers obtained from the monomer which corresponds to the alpha-olefin. The oligomerization is conducted at from 5° C. to 75° C. U.S. Pat. No. 3,985,822 issued Oct. 12, 1976 to Watson describes the production of poly-n-butenes using aluminum chloride as a catalyst and employing a reaction temperature of 65° F. (18° C.) to 115° F. (46° C.).
U.S. Pat. No. 4,407,731 to Imai issued Oct. 4, 1983 describes catalytic compositions, useful in oligomerization and alkylation reactions, prepared by treating a metal oxide support such as aluminum with an aqueous solution of an acid. One of the catalysts suggested for use in the support system of Imai is boron fluoride. U.S. Pat. No. 4,429,177 to Morganson et al issued Jan. 31, 1984 describes obtaining an alpha-olefin polymer in the presence of a 3 component catalyst system comprising a solid absorbant, boron trifluoride and elemental oxygen. U.S. Pat. No. 1,885,060 issued Oct. 25, 1932 to Hofmann et al describes using boron fluoride as a catalyst for propylene or butylene. It is also disclosed that various hydrogen halides may also be utilized with the boron fluoride.
Schmurling et al U.S. Pat. No. 2,369,691 issued Feb. 20, 1945 describes the use of sulfuric acid and metal halides of the Friedel-Crafts type. The catalyst system is stated to be useful in the isomerization of saturated hydrocarbons, the alkylation of cyclic aliphatic hydrocarbons, and in the polymerization of unsaturated hydrocarbons. U.S. Pat. No. 2,404,788 issued Jul. 30, 1946 to Burk et al discloses various aluminate or silicate support systems for boron trifluoride.
U.S. Pat. No. 4,400,565 issued to Darden et al Aug. 23, 1983 describes oligomerizing olefins in the presence of boron trifluoride and a co-catalyst comprising a heterogeneous cationic ion exchange resin. U.S. Pat. No. 2,442,645 to Elwell et al issued Jun. 1, 1948 describes the polymerization of normal lower mono-olefins which are dissolved in liquid sulfur dioxide. The reaction according to Elwell is carried out in the presence of a boron fluoride catalyst.
U.S. Pat. No. 2,406,869 to Upham issued Sept. 3, 1946 describes the preparation of an olefin polymerization catalyst comprising boron trifluoride and a hydrogen halide source. U.S. Pat. No. 2,199,180 to Laughlin which issued Apr. 30, 1940 describes the use of sulfuric acid and phosphoric acid for the polymerization of lower olefins. It is stated in Laughlin that it is desirable when treating the lower olefins to maintain the reaction temperature of above 200° F. (95° C.).
U.S. Pat. No. 2,536,841 issued Jan. 2, 1951 to Dornie describes the use of aluminum halides to polymerize olefins. The reaction temperatures suggested by Dornie are from 0° C. to -164° C. Dornie utilizes a low-freezing non-reacting solvent such as chloroform or sulfur dioxide in his process. U.S. Pat. No. 2,357,926 issued Sept. 12, 1944 to Bannon describes the use of boron fluoride and water for the polymerization of olefins.
U.S. Pat. No. 2,569,383 to Leyonmark et al issued Sept. 25, 1951 describes the polymerization of olefins from mono-olefins and polyolefins to give drying oils. U.S. Pat. No. 2,960,552 to Wasley issued Nov. 15, 1960 describes the use of methylchloride and boron trifluoride gas to polymerize lower olefins. U.S. Pat. No. 2,855,447 issued Oct. 7, 1958 to Griesinger et al describes an example of the polymerization of lower olefins through the use of hydrogen fluoride and boron trifluoride at temperatures of about 175° F. (79° C.). Block et al in U.S. Pat. No. 3,126,420 issued Mar. 24, 1964 describes the use of phosphoric acid and kielsguher to polymerize propylene at temperatures of 450° F. (232° C.) to 650° F. (343° C.). The conditions for Block's reaction are from 600 to 1200 psi (4,100 KPa -8,100 KPa). Griesinger in U.S. Pat. No. 2,855,447 issued Oct. 7, 1958 discloses that olefins may be polymerized with boron trifluoride.
Perilstein in U.S. Pat. No. 3,749,560 issued Jul. 31, 1973 describes the polymerization of a mixture of mono-olefins from C-12 and greater through the use of aluminum trichloride at temperatures of about 15° C. to give polymers having a molecular weight of about 350 to about 1,500. Robert in U.S. Pat. No. 3,932,553 issued Jan. 13, 1976 discusses the polymerization of propylene in the presence of butadiene at 0° C. to 60° C. with boron trifluoride. Robert further discloses the use of phosphoric acid catalytic treatment of the di-olefin at from 130° C. to 250° C. British patent No. 1,449,840 to Sanders published Sept. 15, 1976 describes the alkylation of benzene through the use of a Friedel-Crafts catalyst system.
It has been found in the present invention that a high vinylidene content polymer may be obtained by reacting a lower alkene monomer in the presence of a boron trifluoride and mineral acid catalyst system at about -3° C. to about -30° C. thereby giving an olefin polymer which is useful for producing an oil soluble composition. The olefin polymers of the present invention are highly reactive materials in that they contain a large degree of reactive mono-unsaturation.
Throughout the specification and claims percentages and ratios are by weight, temperatures are in degrees Celsius, and pressures are in KPa gauge unless otherwise indicated. Ranges and ratios utilized herein are illustrative and such may be combined to further describe the invention. It is also understood that mixtures of ingredients may be employed for each stated ingredient. The references cited herein are, to the extent applicable, incorporated by reference for their disclosures.
SUMMARY OF THE INVENTION
The present invention describes a process for preparing a lower alkene polymer from a lower alkene monomer feed-stream, including the steps of: (A) contacting the lower alkene monomer with a catalyst system comprising boron trifluoride and at least one acid and (B) polymerizing the lower alkene monomer in the presence of the catalyst system at a temperature of about -3° C. to about -30° C. thereby obtaining a lower alkene polymer having a molecular weight of about 250 to about 500.
A further feature of the invention is a composition of matter which is a polymer of a C 2-6 mono-olefin having a molecular weight of about 250, preferably at least about 300, to about 500 and a vinyldiene to trisubstituted olefin content of at least 1:4, typically at least 1:3 and more typically at least 3:7 by weight.
Another feature of the invention is a composition of matter which is the polymer of a C 2-6 mono-olefin having the above-described molecular weight and a combined weight ratio of trisubstituted and tetrasubstituted olefin to the vinylidene of less than 9:1, typically less than 8:1, more typically less than 6:1 and most typically less than 4:1. Alternatively, the vinylidene to tetrasubstituted olefin weight ratio is at least 7:11.
Also described herein are various products including the lower alkene polymer, and the reaction product of the lower alkene polymer with an aromatic compound such as phenol, toluene or benzene and their sulfonated derivatives. Further described herein are overbased compositions of the above sulfonated derivatives. The reaction products of the lower alkene polymer and a carboxylic acid acylating agent such as maleic acid or anhydride are also disclosed.
DETAILED DESCRIPTION OF THE INVENTION
The present invention deals with the polymerization of lower alkene monomers to obtain a lower alkene polymer having a molecular weight of about 250, preferably about 300, to about 500. The products obtained in the invention have a high degree of mono-unsaturation content typically at least about 85 mole percent of the polymer, preferably at least about 90% and even more preferably 95%-100%.
The polymerization of the lower alkene monomer to the polymer desirably gives a product which contains a high vinylidene content. A vinylidene structure is as follows:
(R).sub.2 C═CH.sub.2 (A)
where each R group contains at least one carbon atom. As the various R groups become more complex, the later described alkylation process becomes more difficult. Moreover, the presence of a significant amount of trisubstituted olefin (B) or tetrasubstituted olefin (C), as shown below, significantly reduces the reactivity in alkylation reactions.
(R).sub.2 C═CH(R) (B)
(R).sub.2 C═C(R).sub.2 (C)
Thus, internal olefins are not as reactive in alkylation reactions as are vinylidene components.
In the present invention, the vinylidene content may be augmented by any alpha-olefin content present in the product or added to the product. An alpha-olefin is of the formula:
RHC═CH.sub.2 (D)
For convenience in defining the present invention, the following criteria is employed. The vinylidene content of the total mono-unsaturation present is typically at least about 15%, more typically 20% and most typically at least 25%. The weight ratio of vinylidene to trisubstituted olefin is about 1:4 to about 8:1, typically about 1:3 to about 5:1, and often at least 1:4 and more typically at least 1:3. The amount of vinylidene and other substituted olefins are conveniently obtained by carbon 13 NMR as referred to in Determination of Molecular Structure of Hydrocarbon Olefins by High Resolution Nuclear Magnetic Resonance, Stehling et al, Anal. Chem. 38, (11), pp. 1467-1478 (1966). See also 13 C Chemical Shifts of Some Model Olefins by Couperus et al, Org. Magn. Reson. 8, pp. 426-431 (1976). The foregoing articles are incorporated by reference.
In conjunction with the vinylidene content, it is preferred that the unsaturation content of the polymer is as defined as above and determined by ASTM D-1159-66 (Reapproved 1970) herein incorporated by reference.
The lower alkene polymer is obtained from a lower alkene monomer typically containing from about 2 to about 6 carbon atoms. Typically, the lower alkene monomer contains from about 2 to 4 carbon atoms such as butene and most preferably propylene (propene).
The feed stream of the lower alkene monomer is preferably free of diene or higher moieties. The diene or higher unsaturated moieties can lead to the formation of diphenyl alkanes upon alkylation. By being substantially free of diene moieties, it is desired that there be no more than 10%, preferably no more than 5% by weight of diene or higher unsaturated moieties present in the feed stream. Most preferably, it is desired that the feed stream be completely free of diene moieties.
It is also highly desired that the alkene monomer such as the propylene or butene be an alpha olefin. By alpha olefin is meant that the unsaturation in the alkene monomer is between the first and second carbon atoms in the molecular structure. A further desired feature of the present invention is where the lower alkene monomer is at least 95% of a single species. By single species, it is meant that a single lower alkene monomer is the predominant species within the feed stream. That is, where the lower alkene monomer contains 4 carbon atoms, it is desirable that the monomer is substantially pure 1-butene rather than in a mixture with 2-butene or isobutylene. Of course, for the preferred propene only one isomer, e.g., 1-propene, exists.
The feed streams for the present invention are typically obtained through catalytic cracking of petroleum feed stocks. Thus, all of the lower alkene monomers with which the present invention is concerned are available as articles of commerce.
The lower alkene polymer obtained according to the present invention typically has a molecular weight between about 250, preferably about 300, and about 500, preferably about 325 to about 475, more preferably from about 350 to about 450, and most preferably from about 380 to about 420. The lower alkene polymer, as later discussed, is conveniently utilized for the alkylation of benzene or other aromatic compounds which are then further converted to form alkylated aromatic sulfonic acids which are utilized as detergent substrates for overbasing in the lubricant industry. Other uses, as later described herein, are the alkylation of acylating agents such as carboxylic acids and anhydrides, phenols and the like.
The catalyst system employed herein has as a first component boron trifluoride. The boron trifluoride may be obtained as the gas commercially, generated in situ or obtained as the etherate.
The second component utilized as part of the catalytic system is a strong acid such as a mineral acid. The mineral acids include the hydrogen halides, sulfuric acid, sulfurous acid and the various phosphoric acids. Among the phosphoric acids are H 3 PO 4 , HPO 3 and H 4 P 2 O 7 . Any strong acid may be employed in the present invention provided that the desired polymer is obtained. Thus, while phosphoric acid or sulfuric acid are the preferred acids for use herein, any highly protic acid may be used. Thus, strong acid resins such as Amberlyst™ may be used in the present invention. The amount of acid is that amount sufficient to catalyze the reaction typically about 0.005% to about 1% by weight of the polymer.
It is also possible to superacidify the acids employed herein. Thus, it is possible to use oleum (fuming sulfuric acid) or glacial phosphoric acid through the introduction of P 2 O 5 to phosphoric acid in order to increase the acid strength. It has been found, however, that the typical commerical strength acid, e.g., 85% phosphoric or 98% sulfuric are adequate within the present invention to accomplish the desired polymerization of the lower alkene monomer to the lower alkene polymer. Typically, a preferred acid is an aqueous solution containing 70-95% by weight of phosphoric acid (H 3 PO 4 ).
The boron trifluoride is employed such that it saturates the reaction mixture. Due to the strength of both the acid and the corrosive nature of the source of boron trifluoride, it is suggested that the reactions be run in a glass lined or stainless steel vessel. Under the conditions with which the present invention is practiced, it is acceptable to run at atmospheric pressure.
It is believed that the restrictive temperature conditions under which the lower alkene monomer is polymerized in the presence of the catalyst system gives the high degree of unsaturation content retained in the polymer together with the narrow molecular weight distribution. In the present invention, it is highly desired that the product be mono-unsaturated so that it may be alkylated onto an aromatic ring in the desired manner. The subsequent alkylation conditions are such that internal unsaturation in a polymer of similar molecular weight but prepared outside the scope of the present invention will result in degradation of the polymer or products other than the desired alkylation products. Thus, temperature is viewed as being critical to the scope of the present invention in order to obtain the high vinylidene content with the desired 250 to 500 molecular weight. The temperature conditions under which the desired products of the present invention are obtained are from about -3° C. to about -30° C., preferably about -5° C. to about -25° C. and most preferably about -8° C. to about -20° C. It was unexpected that the narrow temperature ranges within which the reaction is run in order to obtain the lower alkene polymer from the monomer would also result in a material which had a high reactive mono-unsaturation content of the desired molecular weight.
The catalyst system as previously discussed may be immobilized, heterogeneous, supported or in any other manner in which catalysts are utilized provided that the objects of the invention are met. The substrates which may be employed in the present invention include kieselguhr, clay, charcoal, aluminosilicates, alumina, silica, diatomaceous earth and various other metal silicates.
A heterogeneous catalyst system would, for example, simply be a mixture of BF 3 (boron trifluoride) and the acid, e.g., phosphoric. Typically, the heterogeneous system is obtained by bubbling gaseous boron trifluoride through the liquid acid/monomer/polymer mixture.
The temperature conditions of the present invention are met through the use of standard cooling devices. It is preferred that the polymerization of the lower alkene monomer to the lower alkene polymer be conducted such that the temperature of the reactants does not exceed the desired parameters for any substantial period of time during the processing. Thus, if a batch system is employed in order to obtain the lower alkene polymer, the reaction vessel and the contents should be maintained within the desired temperature range until substantially no lower alkene monomer is present, e.g., 5% or less. Where a continuous processing system is utilized, the lower alkene polymer is drawn off as it is formed.
Various solvents may be used in the present invention. It is conveniently preferred that a paraffinic hydrocarbon solvent which is normally liquid be employed herein. The solvents should be materials which are easily distillable from the reaction mixture following the polymerization reaction. Suitable examples of solvents include hexane, pentane, heptane, or butane. Other suitable solvents include halogenated aliphatics or carbon disulfide.
The following are examples of the present invention.
EXAMPLE I
A mixture is prepared comprising 200 grams hexane, 8 grams of phosphoric acid and 80 grams of DD1600 filter aid. The filter aid is utilized as the catalyst substrate. The premixture is obtained by first combining the filter aid and the hexane and thereafter adding 85% phosphoric acid to the mixture. The mixture is stirred for about 30 seconds.
A 12-liter, 10-necked round bottom flask equipped with a stirrer, thermometer, dry ice/isopropanol condenser, 4 surface inlet tubes for propylene and 1 surface inlet tube for boron trifluoride is charged with the material described above. An additional 2200 grams of hexane solvent is added to the system.
The mixture described above is cooled to -20° C. and boron trifluroride is introduced to the system at 1.0 cubic foot per hour (1.25 moles/hour) for 20 minutes until the system is saturated. Evidence of saturation will be observed by boron trifluoride fumes venting from the condenser. The rate of flow of the boron trifluoride is then adjusted to about 0.2 cubic foot per hour (0.25 mole/hour). The latter rate of boron trifluoride flow is maintained for the duration of the polymerization reaction.
Propylene gas is then added through the remaining 4 inlet tubes at 20 cubic feet per hour total (25 moles/hour). The temperature bath is maintained at -46° C. to -60° C. to hold the -20° C. charge temperature. The flow rate of propylene is about 1 drop per minute condensed on a dry ice condenser during the propylene addition. A total of 121 cubic feet (150 moles) of propylene total is charged to the reaction vessel.
The propylene and boron trifluoride feed are stopped and the charge is neutralized with 80 grams of caustic soda liquid (50% aqueous). The charge is stirred for several hours to ensure neutralization. The product (lower alkene polymer) is filtered through a cake of approximately 30 grams of the DD1600 filter aid.
The product is then vacuum stripped in a separate 12-liter, 3-necked flask at 30 mm Hg (4 KPa) at 100° C. to remove the hexane. A second strip at 9 mm Hg (1.2 KPa) at 163° C. to remove the light ends results in the desired product in the amount of 5,418 grams.
The process will give near quantitative conversion to the polymer when a closed system is employed, e.g., the excess propylene is not vented.
EXAMPLE II
A 12-liter, 10-necked round bottom flask is equipped with a stirrer, thermometer, dry ice/isopropanol condenser, 4-surface inlet tubes for propylene and 1-surface inlet tube for boron trifluoride. The reaction vessel is immersed in a cooling bath and is charged with 2400 grams of hexane, 120 grams of silica gel and 12 grams of phosphoric acid in that order. The foregoing mixture is stirred at high speed for 15 minutes.
The reaction mixture is cooled to -27° C. and boron trifluoride is added to the system at 1.5 cubic feet per hour (2.25 moles/hour) for a period of 23 minutes until the system is saturated. The boron trifluoride flow rate is then changed to 0.1 to 0.2 cubic feet per hour for the duration of the polymerization. The foregoing flow rate is sufficient to maintain saturation within the system.
Propylene is added through the remaining inlet tubes. The initial feed rate is 20 cubic feet per hour (30 moles/hour). In order to maintain the reaction mixture at -20° C., the flow rate of propylene is decreased by 20%. The bath temperature is maintained at -48° C. to -50° C. to maintain the -20° reaction temperature. The reaction is conducted over a period of about 5-1/2 hours at a rate of 1 drop of propylene per minute condensed on the dry ice condenser during the propylene addition. A total 98.3 cubic feet (148 moles) of propylene was charged to the reactor during the reaction time.
Following complete addition of the propylene, the boron trifluoride feed is stopped and the reaction mixture is neutralized with 200 grams of calcium hydroxide. The reaction mixture is stirred for several hours to ensure neutralization and the charge is filtered through 50 grams of DD1600.
The filtered reaction mixture is then placed in another reaction vessel and vacuum stripped at 100° C. and 72 mm mercury (9.5 Kpa) to remove the hexane. Subsequently, the reaction mixture is raised to 161° C. and a vacuum of 24 mm mercury (3.2 KPa) issued to remove 7 grams of light end material leaving a residue of 4,386 grams of the liquid product.
EXAMPLE III
A detergent alkylate is prepared from toluene and the lower alkene polymer of Example I.
Toluene in the amount of 4517 grams is added to a 12-liter 4-neck flask equipped with a stirrer, thermometer sub-surface tube and ice condenser. Thirty grams of aluminum chloride catalyst are also added to the flask.
The mixture described above is saturated with hydrogen chloride gas blowing through the sub-surface tube at 1 cubic foot (1.5 moles) per hour for 0.3 hours. The mixture at this point is cooled to -5° C.
The sub-surface tube is then replaced by an addition funnel and charged with 3000 grams of the polypropylene of Example I over a period of 1 hour. The reaction is exothermic and is maintained at a temperature between 0° C. and 8° C. Following the complete addition of the polypropylene the reactants are stirred for an additional 3 hours. At this point, 61 grams of ammonium hydroxide are slowly added through an addition funnel. Following complete addition of the ammonium hydroxide, the mixture is stirred for an additional 0.5 hours.
The reaction mixture is then filtered through 30 grams of DD1600 at 20° C. The filtrate is charged to a 12-liter, 4-necked flask equipped with a stirrer, thermometer, goose-neck and condenser receiver flask. The filtrate is then vacuum stripped to 160° C. and 10 mm mercury (1.3 Kpa). The product is then allowed to cool to room temperature and filtered a second time through 30 grams of DD1600 to give 3505 grams of the filtrate as product.
The yield is approximately 95% wherein the product has an Mn by GPC of 402 and a Mw by GPC of 430. The viscosity at 100° C. is 10.79 cks.
A further variation of the use of the composition of the present invention is the sulfonation of the above-described detergent alkylate according to conventional methods. A still further variation of the above example is to overbase the sulfonated detergent alkylate. Both of the foregoing techniques are known to one skilled in the art.
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This invention describes highly reactive polymers obtained from lower monomers. The polymers are particularly useful in alkylation reactions.
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This invention relates to electronic stethoscopes and in particular to a stethoscope in which the output may be compared both by sound and visually on a scope with various sound signals prerecorded on a memory medium.
BACKGROUND OF THE INVENTION
Various pathological conditions of a patient are revealed by auscultation examination. A normal heart and lungs produce normal sounds which are detected by the stethoscope, and if any abnormalities are detected proper corrective steps may be taken Therefore, it is extremely important for a medical diagnostician to recognize and understand normal and abnormal heart and lung sounds.
There are many heart sounds that must be learned by the diagnostician. The human heart has four chambers. During the diastolic or relaxed period, blood flows through the tricuspid valve into the right ventricle and oxygenized blood flows through the mitral valve into the left ventricle. At the end of this very short diastolic period the mitral valve closes followed by the tricuspid valve and the heart muscle contracts in systole while blood is pumped from the right ventricle through the pulmonary valve and blood is pumped from the left ventricle through the aortic valve. There is a sound, called S 1 , that occurs at the closure of the mitral and tricuspid valves and a sound, S 2 , that occurs at the closure of the aortic and pulmonary valves.
With the presence of heart disease the individual sounds are often split and may be heard as two sounds on each of the two basic S 1 and S 2 sounds. And in addition to the basic sounds, there are pathologic sounds which may be caused by blood passing through a tight valve or a pathologically enlarged valve opening. And certain disease processes may cause rubbing sounds produced by rubbing of the heart wall on the tissue covering that surrounds the heart. Certain diseases can change or vary the heart sounds. For example, if S 1 appears to be louder than S 2 , it suggests a tightening of the mitral valve or mitral stenosis, whereas an unusually soft S 2 suggests mitral regurgitation. Heart disease is suggested if any component separation occurs during expiration, if separation seems excessive, or if one component is persistently missing.
Lung sounds also have two components, that produced by inspiration and that by expiration. With a presence of disease in the lungs the normal lung sounds are disrupted and certain pathologic crackles, rates and wheeze sounds are produced which, in most instances, would point to a certain disease going on in the patient's pulmonary and even systemic system.
The foregoing material discusses only a small fraction of the various sounds that may be detected with a stethoscope. There is a multitude of murmurs, hums and clicks that may be heard at various body locations while in various positions. It is thus apparent that the science of auscultation is difficult and that certain medical technicians, such as ambulance technicians or student who may not have thoroughly mastered the science, would benefit greatly from a stethoscope that included a diagnostic capability.
Briefly described, this invention is for a self-contained electronic stethoscope in a housing that includes a prerecorded record of typical sounds, a recorded image of the external pulse recordings of the sound and a suggested diagnosis. The electronic stethoscope normally outputs into a small speaker and to a small oscilloscope for viewing the signal, and depressing a momentary contact switch will divert the prerecorded record output to the speaker and scope for comparison with the stethoscope sounds
DESCRIPTION OF THE DRAWINGS
In the drawings which illustrate the preferred embodiment of the invention.
FIG. 1 is a schematic drawing of the electronic stethoscope with diagnostic capability;
FIG. 2 is a perspective view of the stethoscope housing; and
FIG. 3 is a top plan view thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention is for an electronic stethoscope that has the capability of diagnosing physical problems by providing a means for comparing a stethoscope sound and oscilloscope image with a typical sound and identified image that has been prerecorded on a magnetic memory disc within the hand held stethoscope housing containing amplifying circuitry, the prerecorded memory and a battery for supplying power.
The self-contained circuitry of the stethoscope is illustrated in FIG. 1 and comprises a microphone 10 located in the stethoscope chest piece, immediately followed by wide band low power amplifier 12 the output of which is applied to the switch 14 . Switch 14 preferably is comprised of four ganged, single-pole, single-throw switches which are connected into a spring loaded, momentary contact, single double-pole, double-throw configuration so that, in its normal state, one pole couples the amplifier 12 to a speaker for a sound output and the second pole couples the amplifier 12 to a monitor for a visual output of the waveform. When depressed, the first pole of switch 14 couples a prerecorded sound to the speaker and the second pole couples it to the monitor.
Thus, the output of amplifier 12 is coupled to terminal “a” of the switch 14 and normally passes to pole 16 of the switch. Pole 16 of switch 14 is connected to pole 20 of a double-pole double-throw switch 22 which, in a first position passes the signal from amplifier 12 to a second amplifier and a speaker and, in the second position, diverts the signal to the amplifier and speaker through a low pass filter 24 which may be switched on to eliminate all high frequency sounds above approximately 500 Hertz.
The output of the switch 22 is taken from the second pole 26 and after passing through a “privacy” phone jack 28 , is applied to the second or power amplifier 30 , the output of which is applied through a volume control 32 , having an “ON-OFF” power switch, to a speaker 34 . The output of amplifier 12 is also coupled to terminal “c” of the switch 14 and normally passes to pole 18 of the switch which is connected to the “X” or vertical deflection input on a small monitor 36 having, for example, a one or two inch oscilloscope tube.
Various heart and lung sounds are prerecorded along with a very short diagnosis of the defect causing the sound. All the heart and lung sounds and the associated suggested diagnoses are recorded on a miniature diskette which can be easily accommodated with the associated circuitry within the hand-held housing of the stethoscope. The approximate sector of the expected recorded sound on the diskette is selected by depressing a button on the housing and the recording may be “inched” forward and backward to find the desired location by an “up” or “down” sliding of the button of the spring biased switch 14 on the side of the housing.
The miniature memory diskette is contained in the memory and microprocessor, the output of which is converted into analog and applied to input terminals “b” and “d” of the switch 14 so that, when switch is momentarily depressed, the prerecorded signals are applied to the speaker 34 and to the monitor 36 .
FIG. 2 is a perspective view illustrating one end surface and the rear surface of the stethoscope that contains the selection controls and the audio and visual outputs and FIG. 3 is a top plan view illustrating the chestpiece on the stethoscope.
The stethoscope is contained in a hand-held size housing 40 approximately three inches square and one inch thick. Centered on one of the square surfaces is a funnel shaped chestpiece 42 about two inches long and containing a very thin diaphragm near its narrow end that is backed by the microphone 10 (not shown). A rubber ring 44 is stretched over the rim of the chestpiece to assure a tight seal to the skin of a patient.
On one side of the housing 40 are two controls: The volume control 32 which regulates the audio volume, and the switch 14 which is depressed to momentarily switch on the prerecorded sound from the memory 38 and which also may slide up and down for making forward and backward adjustments in the memory location.
The square surface opposite the chestpiece 42 contains the phone jack 28 , the small speaker 34 , and the monitor 36 which may have a two-inch or three-inch oscilloscope tube Also on this surface are seven buttons 46 , one of which is the low pass filter switch 22 , and the remaining six are for selecting the various pre-recorded subjects on the disk in the memory 38 . For example, the six buttons may be labeled Pulmonary Valve, Aortic Valve, Tricuspid Valve, Mitral Valve, Lungs, Blood Vessels. If Blood Vessels button has been depressed the switch button 14 may be moved so that Carotid Artery is displayed on the monitor.
In use, the stethoscope is turned ON with the power switch on the volume control 32 and the chestpiece is pressed at the appropriate body locations of a patient. The sounds picked up by the microphone 10 may be heard by earphones plugged into the phone jack 28 or they may be amplified by amplifier 30 and heard through speaker 34 while a visual representation of the sounds are seen by the monitor 36 . If the technician suspects any disorders, he may press the appropriate button 46 and adjust the sliding switch 14 to the location at which matching sounds are heard on the earphones or speaker and seen on the monitor from the prerecorded diskette. For each prerecorded sound visual, there is a brief message suggesting the problem; for example, the technician may have found coincidence between a patient's sound with a pre-recorded sound labeled “Mitral Regurgitation” indicating that the patient's examination showed a probability of a weak mitral valve and having a backward flow of blood through the valve into the left atrium.
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A self-contained, hand-held electronic stethoscope including built-in chestpiece, speaker and visual monitor, includes a memory containing prerecorded heart and lung sounds along with a brief description of the malady producing the sounds so that the technician may compare the actual sounds with the prerecorded sounds and observe a suggested diagnosis on the monitor.
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CROSS REFERENCES TO RELATED APPLICATIONS
The present invention contains subject manner related to Japanese Patent Application JP 2005-311680 filed in the Japanese Patent Office on Oct. 26, 2005, the entire contents of which being incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fluid-structure coupled numerical simulation method and a program for a fluid-structure coupled numerical simulation storage device. Particularly, the present invention relates to the aforementioned method and program, in which when applying a fluid to a film structure, assuming that a film surface is a surface of a fixed area in a computational mesh, a fluid analysis is executed in the same solver with respect to the relationship between a repulsive force of the film surface of the film structure and a fluid pressure.
2. Description of the Related Art
In the past, when simulating physical action of a design model, for example, conducting a thermal conductivity analysis, fluid analysis, structural analysis, electromagnetic field analysis, electromagnetic wave analysis and the like by a computer to verify the design model, a coupled analysis in which two or more kinds of simulation are applied is performed on an object model, corresponding to the object model for analysis being complicated.
In such coupled analysis, it is necessary to set a plurality of physical parameters for element groups if two or more physical models are provided, and so work of setting becomes complicated when one-dimensional list is used. Further, when boundary conditions are set, it is necessary to perform the setting while considering a setting condition for each of the element groups, that is, which boundary corresponds to which physical model, thereby bringing the complexity to the work. Japanese Patent Application Publication No. 2002-245097 discloses a coupled analysis method of easily setting conditions on element groups and boundaries regarding an object model, a method of setting the analysis conditions, a storage device and program in a coupled analysis system using two or more physical models.
FIG. 1 shows the coupled analysis system disclosed in the above-mentioned patent reference configured to have a CPU (Central Processing Unit) 1 , display 2 , input device 3 such as a mouse and filing device (storage device) 4 . The CPU 1 implements CAD model preparation processing 10 by which a model to which a numerical simulation is implemented is prepared. The prepared model is divided into mesh (elements), and at this time, mesh preparation processing 11 that defines a group and boundary of each mesh is implemented. Groups are registered in a group list 6 , boundaries are registered in a boundary list 7 , and the corresponding relations between groups and boundaries are registered in a corresponding list 5 . As shown in FIG. 1 , the corresponding list 5 is provided in the filing device 4 . List-registration processing 12 that stores group numbers and corresponding boundary numbers is performed, and analysis conditions with respect to the groups and boundaries of the meshes (elements) divided are set by element group analysis-condition-setting processing 13 and element boundary analysis-condition-setting processing 14 . For example, thermal conductivity is set to the element groups and a temperature and thermal conductivity are set to the boundaries in the thermal conductivity analysis. Further, a young's modulus or the like is set to the element groups and a weight condition or the like is set to the boundaries in the structural analysis. Both the analysis-condition-setting processings 13 and 14 are linked mutually.
Subsequently, physical-model simulation/computation processing 15 and computed-result display processing 16 are implemented. Here, computation is implemented in the computation processing 15 using the model divided into mesh and analysis conditions, thereby obtaining a solution. A general-purpose thermal analysis program, structural analysis program and fluid analysis program are used in the computation processing 15 . The result display processing 16 is performed such that the computed result obtained by the computation processing is output to a screen of a display 2 . As described above, the CPU performs such steps 10 and 11 of setting physical models of the element groups constituting the object model, and step 12 of retrieving boundaries of the object model corresponding to the element groups that were set. Further, the CPU performs a step 13 of reflecting the physical models of the element groups to the retrieved boundaries on analysis-condition-setting screen for the boundaries of the object model, and a step 14 of setting analysis conditions of the boundaries on the analysis-conditions-setting screen for the boundaries reflected. By using a principle of a specific group and the boundary thereof having a common physical-model characteristic, correlation between the group and boundary is reflected on a boundary condition setting screen, and the physical model of the group is set to automatically retrieve the boundary corresponding to the group, and the analysis conditions of the boundary are set on the boundary condition-setting screen.
As described above, the technology described in Japanese Patent Application Publication No. 2002-245097 includes the function of displaying a two-dimensional list of the physical models (thermal conductivity, fluid, structural analysis, static electromagnetic field and electromagnetic field) and names of the boundaries. Therefore, referencing the corresponding list 5 in the filing device 4 , a situation in which the physical model of each element group is assigned is displayed on the boundary list and boundaries to which the conditions-setting in the boundaries list are needed are automatically checked. For example, a checked result is displayed with a circle or the like, and so the setting of the boundary condition of the physical model to which each boundary corresponds can be performed by clicking (or double clicking) an area of the boundary name checked. Accordingly, since the two-dimensional list is prepared as described above, the setting of physical parameters to the element groups becomes easy in an achievement analysis having a plurality of physical models. Further, situations of the physical parameters set to the element groups are determined, the boundary condition to which setting is needed is automatically checked, and can be set in the boundary list, thereby the setting of boundary conditions being facilitated. Furthermore, the element group list, boundary list and shapes of models can be output simultaneously, thus facilitating understanding of the setting conditions for analysis.
Japanese Patent Application Publication No. 2000-271734 discloses a fluid-solidification analysis method to which computer simulation is applied. This method is to find an optimal method and optimal condition for producing a high quality product without casting defects such as a flow defect caused by the decrease in temperature in a molten metal flow, in the case where metal melt material is used as fluid to form cast or die-cast products.
The state of molten metal solidified is modeled with a solid-phase rate which shows a rate of the solid phase existing in the liquid phase based on the temperature of each minute element. The molten metal is treated as Newtonian fluid in the state of the solid-phase rate of 0% at a temperature higher than the liquidous line temperature, is treated as non-Newtonian fluid in the solid-liquid co-existent area at a temperature higher than the solidus line temperature and lower than the liquidous line temperature, and is treated as the obstacle not fluid in the state of the solid-phase rate of 100% at a temperature lower than the solidus line temperature. Thus, an optimum flow-field analysis method is applied to each solidified state, enabling an analysis result with high accuracy for the process to be practically obtained in a short period of time.
FIG. 2 shows a flow chart of the fluid-solidification analysis method to which the computer simulation described in the above-described patent reference is applied. In order to implement the fluid-solidification analysis of molten metal inside a mold, a shape model is prepared based on a molded product by injection molding and the mold used for the injection molding in step S 1 . An analysis shape model divided into minute elements is prepared using mesh in step S 2 . The analysis model is suitable for a difference method, finite element method, boundary element method, FAN method, control volume method and the like that are fluid-solidification analysis methods.
In step S 3 , input condition data such as physical property data, boundary conditions, process conditions and the like necessary for the fluid-solidification analysis after preparing the analysis shape model are determined and input. Hereupon, the input condition data are set for simulating a process that produces a molded product by the numerical analysis with respect to the analysis shape model. Those are conditions necessary for the analysis, such as a inflow velocity of molten metal, inflow temperature and filling time, mold temperature, values of dynamic physical properties and thermal physical properties of the mold, values of dynamic physical properties and thermal physical properties of the molten material, boundary conditions (such as thermal boundary condition) and the like.
In the next step S 4 , a process in which the molten metal is filled inside the mold is simulated using a numerical analysis method on the basis of the given input condition data. When implementing the analysis, the solidified state of molten metal in each minute element is modeled using the solid-phase rate that shows a rate of solid phase existing in the liquid phase from the temperature of each minute element, and a state of the molten metal is determined. Specifically, as shown in step S 5 , the state of the molten metal, which is the complete liquid-phase state, solid-liquid co-existing state or complete solid-phase state, is determined from the temperature of the molten metal. The complete liquid-phase state is the range at a temperature higher than the liquidous line temperature and the solid-phase rate is 0%. The solid-liquid co-existent state is the range at a temperature higher than solidus line temperature and lower than liquidous line temperature. The complete solid-phase state is the range at the temperature lower than solidus line temperature and the solid-phase rate is 100%.
After the state is determined, an optimal flow-field analysis method is applied to each solidified state based on the state determined, and the simulation is implemented using the numerical analysis method to conduct a flow analysis. The flow analysis employing the numerical analysis method is implemented at predetermined time intervals in accordance with the input condition data and the solid-phase rate. Here, the predetermined time interval is an interval in the range of about 0.001 to 0.01 sec. When implementing the flow analysis to the state in which the molten metal in each minute element is in the solid-phase rate of 0% at the temperature higher than the liquidous line temperature, the flow analysis is implemented regarding the molten metal as Newtonian fluid. Further, in the state in which the molten metal in each minute element is in the solid-liquid coexistent range at the temperature higher than the solidus line temperature and lower than the liquidous line temperature, the flow analysis is implemented regarding the molten metal as non-Newtonian fluid. Furthermore, in the state in which the molten metal in each minute element is in the solid-phase rate of 100% at the temperature lower than the solidus line temperature, the molten metal is treated as the obstacle instead of fluid and the flow analysis is not implemented.
After the fluid analysis, in order for the filling state of molten metal in the mold being changed by the result of the fluid analysis to be reflected in temperature distribution, temperature analysis is implemented in step S 6 regarding temperature changed situations of the molten metal and mold using the numerical analysis method at predetermined time intervals of about 0.01 to 0.02 sec. After the temperature analysis, whether to continue the analysis is judged from the given input condition data, and in the case of “NO”, operation goes back to the step S 4 , and in the case of “YES”, operation proceeds to step S 8 to end. Further, positions such as flow defect portions where defects may occur are predicted in step S 8 based on the analysis result obtained in step S 7 indicating molten metal unfilled portions.
If the occurrence of defects are predicted in step S 8 , as shown in step S 9 , at least one of the conditions of the analysis shape model and input condition data is changed and each of process from the step S 1 to step S 8 is repeated until it is recognized that the occurrence of defects is not predicted. Then, the processing ends when the occurrence of defects is not predicted in the step S 8 .
As described above, Japanese Patent Application Publication No. 2002-245097 discloses the technology to simplify settings of boundary conditions that become complicated when the structural analysis and fluid analysis are implemented, and Japanese Patent Application Publication No. 2000-271734 discloses the technology to implement the fluid-solidification analysis of molten metal in a mold. Problems in the above-described computational solving method have not sufficiently been solved with a simplified method, and there remains complexity in the computation and modeling when implementing the fluid-structure coupled simulation or the like.
For example, there are provided methods of simulating a fluid-structure coupled processing phenomenon in a process of liquid being applied on a film. In such phenomenon a position or shape of a surface of the film is changed by the behavior of liquid discharged and the liquid flows on this surface, and so the phenomenon progresses while both the behaviors of the film and liquid being closely related to each other. There is proposed, for example, a method in which two solvers for a fluid and structure are provided and computation progresses while exchanging information on pressure distribution and a structure position between the two solbers. Further, there is provided another method in which a coupled Jacobian matrix is prepared using a finite element method, fluid equation or structure equation and the like, and the matrix solution is obtained. Although these methods are accurate, computational load is high and a convergence computation becomes unstable in the case where film is greatly transformed or the film touches another structure.
SUMMARY OF THE INVENTION
In view of the above, it is desirable to provide a fluid-structure coupled numerical simulation method in which a fluid-analysis and a structure-analysis can be implemented in one solver. In this method, a film surface is assumed to be the surface of a solid area in a computational mesh, when simulating a fluid-structure coupled phenomenon in the process of a liquid being applied on the film, in which a position and shape of the film surface are changed by the behavior of the liquid discharged and further the liquid flows on this surface.
It is further desirable to provide a fluid-structure coupled numerical simulation method in which a fluid-analysis and a structure-analysis are implemented in one solver. In this method, a film surface is assumed to be the surface of a solid area in a computational mesh, when simulating a fluid-structure coupled phenomenon in the process of a liquid being applied on the film, in which a position and shape of the film surface are changed by the behavior of the liquid discharged and further the liquid flows on this surface. Further, this method is capable of simulating a shift amount of the film surface of a film-structure in each computational time step from a balance between a pressure obtained from a fluid computation and a repulsion force obtained from a tension and curvature of the film structure by assuming that the film-structure has no rigidity for bend.
It is further desirable to provide a program for a fluid-structure coupled numerical simulation storage device in which a fluid-analysis and a structure-analysis are implemented in one solver. In this program, a film surface is assumed to be the surface of a solid area in a computational mesh, when simulating a fluid-structure coupled phenomenon in the process of a liquid being applied on the film, in which a position and shape of the film surface are changed by the behavior of the liquid discharged and further the liquid flows on this surface. Further, this program is capable of simulating a shift amount of the film surface of a film-structure in each computational time step from a balance between a pressure obtained from a fluid computation and a repulsion force obtained from a tension and curvature of the film structure by assuming that the film-structure has no rigidity for bend.
According to an embodiment of the present invention, there is provided a fluid-structure coupled numerical simulation method using a finite volume method employing an orthogonal mesh and a computer and memory setting a solid area based on a solid rate inside a computational mesh and at a tangent position to each mesh. The fluid-structure coupled numerical simulation method includes the steps of: setting initial and boundary conditions of a shape, shift computed area, tension, feeding velocity and the like of a moving film structure; setting a velocity boundary in the tangent direction of the film structure by computing a position and shape of the film structure; and computing a curvature of the film structure. Further, the method includes the step of computing a pressure balance based on the balance between a pressure obtained from a fluid computation and a repulsive force obtained from the tension of the film structure and curvature thereof computed in the curvature computing step to implement processing of a mutually-coupled phenomenon between the film structure assumed to have no rigidity for bend moving in a predetermined direction and a fluid flowing on a surface of the film structure. In this method, a shift amount of a film surface for each time of the computing steps is simulated using the same program.
According to another embodiment of the present invention, there is provided a program for a fluid-structure coupled numerical simulation storage device, using a finite volume method employing an orthogonal mesh and a computer and memory setting a solid area based on a solid rate inside a computational mesh and at a tangent position to each mesh. The program includes the steps of: setting initial and boundary conditions of a shape, shift computated area, tension, feeding velocity and the like of a moving film structure; setting a velocity boundary in the tangent direction of the film structure by computing a position and shape of the film structure; and computing a curvature of the film structure. Further, the program includes the steps of computing a pressure balance based on a balance between a pressure obtained from a fluid computation and a repulsive force obtained from the tension of the film structure and the curvature thereof computed in the curvature computing step to implement processing of a mutually-coupled phenomenon between the film structure assumed to have no rigidity for bend moving in a predetermined direction and a fluid flowing on a surface of the film structure. In this program, a shift amount of a film surface for each time of the computing steps is simulated using the same program.
According to the embodiments, when a film coating process is considered, stable coating conditions based on a film tension, a fixed roller position, a film feeding velocity, a coating-liquid discharging velocity, a viscosity of coating liquid and a shape of discharge nozzle and the like can be examined on the simulation using a simple procedure. Therefore, a fluid-structure coupled numerical simulation method and a program for a fluid-structure coupled numerical simulation storage device are obtained, with which computation can be implemented with small load, stability and high velocity when implementing the fluid-structure coupled numerical simulation for targeting the behavior of fluid with which a film structure is coated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a configuration diagram showing a coupled analysis system of related art;
FIG. 2 is a flow chart of a fluid-solidification analysis method of related art;
FIG. 3 is a schematic view of a running path of a coating device, showing a fluid-structure coupled numerical simulation method according to an embodiment of the present invention;
FIG. 4 is a view showing a computational model of the coating device shown in FIG. 3 ;
FIG. 5 is a system diagram showing a computer and memories that implement the fluid-structure coupled numerical simulation according to an embodiment of the present invention;
FIG. 6 is a flow chart showing a fluid-structure coupled numerical simulation method according to an embodiment of the present invention;
FIGS. 7A and 7B are explanatory views showing divided mesh, in which FIG. 7A shows the divided mesh at the start of computation in a fluid-structure coupled numerical simulation method according to an embodiment of the present invention, and FIG. 7B shows the divided mesh when considering a curvature of a film structure in a fluid-structure coupled numerical simulation method according to an embodiment of the present invention;
FIG. 8 is a display screen of a coupled boundary surface at the start, showing a computed result of a fluid-structure coupled numerical simulation method according to an embodiment of the present invention; and
FIG. 9 is a display screen of a coupled boundary surface after a predetermined time has passed, showing a computed result of a fluid-structure coupled numerical simulation method according to an embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A fluid-structure coupled numerical simulation method and a program for a fluid-structure coupled numerical simulation storage device according to embodiments of the preset invention are explained in the followings with reference to FIGS. 3 to 9 . FIG. 3 is a schematic view of a running path of a coating device, showing a fluid-structure coupled numerical simulation method according to an embodiment of the present invention. FIG. 4 is a view showing a computational model of the coating device shown in FIG. 3 . FIG. 5 is a system diagram showing a computer and memories that implement the fluid-structure coupled numerical simulation according to an embodiment of the present invention. FIG. 6 is a flow chart showing a fluid-structure coupled numerical simulation method according to an embodiment of the present invention. FIG. 7A shows an explanatory view showing divided mesh at the start of computation of a fluid-structure coupled numerical simulation method according to an embodiment of the present invention. FIG. 7B shows an explanatory view showing divided mesh when considering a curvature of a film structure in a fluid-structure coupled numerical simulation method according to an embodiment of the present invention. FIG. 8 shows a display screen of a coupled boundary surface at the start of film moving, showing a computed result. FIG. 9 is a display screen of a coupled boundary surface after a predetermined time has passed, showing a computed result.
Hereinafter, a fluid-structure coupled numerical simulation method according to an embodiment of the present invention is explained with reference to FIGS. 3 to 9 . This embodiment is applied to a coating system in which a surface of a film structure is coated with a fluid or the like. A coating device 17 shown in FIG. 3 is a device assumed in this simulation example. A fluid 21 is discharged from an outlet 20 of a nozzle 19 onto a belt-shaped flexible film 18 being fed, and the film 18 is coated with the fluid 21 . The film 18 is set to have a predetermined tension between two feeding rollers 22 , 23 provided between a feeding reel and a winding reel not shown in the figure.
FIG. 4 shows the initial state of a physical simulation model of the coating device 17 shown in FIG. 3 . An area 24 under a line segment connecting the point A to point D in FIG. 4 is defined as a moving object area, where a solid-area surface position inside a computational mesh assumed to be a solid-surface is gradually changed in each computational mesh prepared using a known mesh-preparation processing. A film surface of the film 18 is expressed by interpolating the solid-area surface positions. Further, a boundary condition is set so that the fluid 21 is discharged from the outlet 20 of the nozzle 19 . Other than those, tension T by which the film 18 is pulled to the feeding reel side and to the winding reel side and a film feeding velocity V are input as computational conditions.
An initial shape of the film 18 of this coating device 17 has a concave curvature at the point B and point C at both right/left ends of the nozzle 19 in FIG. 4 , and so force pushing the film 18 upward in the direction of the nozzle 19 is worked, which presumably affects the shape of the film 18 to enter the nozzle 19 . In this regard, if a computer (hereinafter called a CPU) is used to determine whether to make the film 18 and the nozzle 19 in contact or not, this problem is solved, however, typically the load becomes high when the decision of contact/non-contact is implemented during the numerical computation and also simulation may become unstable. Further, in this embodiment, since the film 18 obviously moves in the negative direction of Z axis (minus z-axis direction), a moving range in the computational process is limited by assuming that the film surface of the film 18 does not move in the positive direction of z axis (plus z-axis direction) from the initial state, thereby reducing the computational load in the CPU.
FIG. 5 is a system diagram showing a relation between the CPU and memories for explaining a fluid-structure coupled numerical simulation method according to an embodiment of the present invention, when the surface of a film structure is coated with a fluid. FIG. 5 shows: a host CPU 25 for computational processing of the simulation according to an embodiment of the present invention; an input device 26 such as a mouse, keyboard and the like; a display 27 that displays computational situations and results; memories 28 , 29 such as ROM and RAM; and a coating device 17 constituting a fluid-structure body shown in FIG. 3 and to which the coupled numerical simulation is implemented. The host CPU 25 controls the coating device 17 , input device 26 , display 27 and memories 28 , 29 via a bus 30 .
FIG. 6 shows computational procedures of the host CPU 25 when simulating the coating device shown in FIGS. 3 and 4 . In FIG. 6 , at step ST 1 , initial settings and boundary condition settings and the like are implemented. Regarding the film 18 , a film moving computational area of the moving object area 24 shown in FIG. 4 , a tension T of the film 18 and a feeding velocity of the film 18 and the like are set.
The mesh division is implemented by the infinite volume method using a known orthogonal mesh, and a solid rate for each mesh and a position of each mesh in the tangent direction that show a flow state of fluid are set at the next step ST 2 . The settings regarding a position, shape, velocity-boundary in the tangent direction of the film 18 are implemented at step ST 3 . FIG. 7A shows the state of mesh division at the portion corresponding to the nozzle 19 before the film 18 moving, and shows each computational mesh (computational cell) 31 where each element shown with broken line is computed.
A curvature of the film 18 is computed at step ST 4 . In this regard, the film 18 in this embodiment is assumed to have no rigidity for bend, and a shift amount of the film surface in each computational time step is computed based on a balance between a repulsive force obtained from a tension and curvature computation of the film 18 and a pressure obtained from a fluid computation in step ST 5 mentioned later on. In this regard, assuming that a film surface of the film 18 is represented by a surface of a solid-setting area, a position, shape and shift amount of the film surface of the film 18 are computed by gradually increasing/decreasing the solid-setting area in each computational mesh in accordance with the shift amount of the film 18 .
Further, when the film 18 moves in the direction of a normal line of the film surface or moves in one direction dominantly, a balance of force only in that componential direction may be computed to reduce the computational load. Further, in order to stabilize the computation, a position of the moving film 18 may be limited not to exceed the initial position set at the step ST 1 .
The computation of the fluid 21 is implemented and the pressure balance is computed at step ST 5 . At the time of the fluid computation in the step ST 5 , considering the state of feeding the film 18 other than a velocity in the moving direction of the film 18 as the velocity-boundary conditions on the film surface of the film 18 , a tangent velocity equivalent to the feeding velocity may be computed in the computational step for each mesh. On implementing the computation of the fluid 21 , a fluid pressure in the computational cell 31 of each mesh is computed, thus obtaining a moving velocity in the direction of the normal line of the film surface and a position of the film surface in the next time step from a motion equation {mδu z /δt=−P cell A}. Here, “m” denotes the mass of film, “u z ” denotes a moving velocity in the z-axis direction of the film 18 , “P cell ” denotes a fluid pressure in each mesh and “A” denotes the area of a computational cell.
Next, after moving a position of the film surface of the film 18 , the film surface after movement and transformation is obtained by interpolation as shown in FIG. 7B . In this state, a velocity equivalent to the feeding velocity of the film is set in the direction of the normal line at the boundary of the surface of the film 18 , again the fluid computation is implemented to compute a pressure, and then a film position in the subsequent mesh is computed. It should be noted that a repulsive force of P′=2γK is generated in accordance with tension γ and curvature K of the film 18 in the transformed state of the film 18 . Therefore, after computing the curvature of the film 18 in the computational cell 31 of each mesh, only a balance of repulsive force of a component in the z-direction shown in FIG. 7B is considered for simplification among the force that works in the direction of the normal line of the film 18 in this embodiment. In practice, an inclined but vertical component z′ shown with broken line in the z-axis direction is selected, and the repulsive force (P′=2γK) in each area of the computational cell 31 is added as shown in step ST 6 to the aforementioned motion equation, implementing computation using the following equation 1;
[Equation 1]
mδu z /δt=−P cell A+ 2 γK cell A·n z (1)
where the “n z ” is a unit vector in the direction of z-axis.
After the step ST 6 , then after (t+Δt) has elapsed, operation goes back to the step ST 3 through the step ST 7 , then the computational processing in each computational cell 31 is repeated from the step ST 3 to the step ST 7 .
A liquid having free surface, gas, compressible fluid, and non-Newtonian fluid in which the transform in a pressure state at an arbitrary point is not proportional to a temporal change rate can be set as a fluid in the aforementioned computation. Further, in order to consider the state where the film surface of the film 18 is pressed by some kind of mechanism or structure, other than the repulsive force by the tension and curvature of the film 18 , a pressure on the bottom surface of the film 18 may be designated in advance to be added for computation.
FIGS. 8 and 9 show examples of screen that displays the relation between the nozzle 19 and the film surface of the film 18 after computational results for each computational cell 31 described above are processed. FIG. 8 shows the initial state of t=1, and FIG. 9 shows the state of t=2. The state of curvature of the film 18 , flow of the fluid 21 and thickness of coating in each computational cell 31 of the fluid and the like can be seen directly. From the results thereof, using the above-mentioned computational method shown with equation 1, it is confirmed that the computation can be implemented stably in one simplified solver by focusing on the balance between a fluid pressure and a repulsive force obtained from tension and curvature of the film and by assuming that the film surface is the surface of solid area inside the computational mesh. The stable computation can be implemented even in the case where the film 18 is in contact with other structures and even in the case where the transform of the film 18 is considerable. Also, from the results thereof, information on the shape of film, shape of liquid surface, thickness of coating, pressure distribution, flow vector and the like can be obtained. It should be appreciated that an optimal coating condition can be examined at the time of simulation, while changing the tension of the film 18 , positions (fixed points) of feeding rollers 22 , 23 , feeding velocity of the film 18 , discharge velocity of the fluid 21 that is a coating liquid, viscosity of the fluid 21 , the shape of the discharge nozzle 19 and the like.
Though the initial position of the film 18 in this embodiment is shown with the line segment from point A to point D as shown in FIG. 4 , the line segment can also be defined as a curve. When there is provided a mechanism or the like by which the film is pushed upward in the direction of the nozzle 19 at a setting area of the film 18 , that effect can be taken into consideration by adding the pressure of that amount to the right side of the equation 1. In this embodiment, assuming that the film 18 does not move in the positive z-axis direction from the initial position, restriction is imposed to obtain high speed computation. However, that restriction can be cancelled or the range of restriction can be narrowed and, for example, a state in which the film 18 is wound into the nozzle 19 can also be computed.
Further, a Newtonian fluid, non-Newtonian fluid in which a viscosity coefficient and a pressure change at an arbitrary point are not proportional to a temporal change rate and a compressible gas can also be set as the fluid 21 to be computed. For simplification, the computation is implemented in this embodiment by focusing only on the z-axis direction among the moving directions of the film 18 , however, the computation may be implemented by focusing on the normal line direction of the film surface. By changing such computational settings, an embodiment of the present invention can be applied to the discharge nozzle 19 with complicated shape. Further, not limited to simulation of a liquid-coating process, this computational method can also be applied to simulation analysis of a floating state of a tape caused by an air filter and to the simulation analysis of the tape path in the vicinity of a magnetic head, for example.
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.
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A fluid-structure coupled numerical simulation method is provided. The method uses a finite volume method employing an orthogonal mesh and a computer and memory setting a solid area based on a solid rate inside a mesh and at a tangent position to each mesh, including the steps of: setting initial and boundary conditions of a moving film structure; setting a velocity boundary in the tangent direction of the film structure by computing a position and shape thereof; and computing a curvature thereof. The method further includes the step of computing a pressure balance based on a balance between a pressure obtained from a fluid computation and a repulsive force obtained from the tension and curvature of the film structure to implement processing of a mutually-coupled phenomenon. A shift amount of the film surface for each time of said computing steps is simulated using the same program.
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FIELD OF THE INVENTION
[0001] The present invention relates to a steam iron for receiving a fragrance cartridge, and a fragrance cartridge for such a steam iron. The present invention also relates to a method of imparting a fragrance to steam intended to be sprayed over garments during ironing by a steam iron.
BACKGROUND OF THE INVENTION
[0002] It is known that ironing a fragrance into a garment will result in the fragrance being released from the garment for an extended period of time. For example, the garment can be pre-sprayed with a liquid fragrance prior to ironing. However, pre-spraying the garment is time consuming and may result in the liquid fragrance staining the garment.
[0003] Fragrance may also be imparted to the garment by pouring drops of a fragranced essential oil into the water tank of the steam iron. Therefore, when the steam iron is operated, the liquid water in the water tank is evaporated and is imparted with the fragrance of the essential oil. However, it is difficult for the user to judge how much essential oil should be added to the water tank. Furthermore, the essential oil in the water tank does not evaporate with the water and so most of the essential oil remains in the water tank and thus the steam does not have a strong fragrance. Additionally, the water tank needs to be completely emptied of liquid water and essential oil before a different fragrance is used.
[0004] U.S. Pat. No. 6,351,901 discloses a steam iron with a steam generating device for generating steam and an application device for releasing additives to the steam. The application device consists of a capillary device for the release of additive to the steam.
SUMMARY OF THE INVENTION
[0005] It is an object of the invention to provide a steam iron and a method of imparting a fragrance to steam produced by a steam iron which substantially alleviates or overcomes the problems mentioned above.
[0006] According to the present invention, there is provided a steam iron comprising a sole plate, said sole plate comprising a steam channel for the passage of steam, an ironing surface, vents for the passage of steam between the steam channel and the ironing surface, an aperture extending between the steam channel and the ironing surface, and a fragrance cartridge being received in said aperture such that it extends into the steam channel to diffuse fragrance in the steam channel, wherein the aperture secures the fragrance cartridge in the sole plate such that the fragrance cartridge is flush with the ironing surface.
[0007] In use, the user may supply fragrance to the fragrance cartridge. Upon operation of the steam iron, steam flows along the steam channel and is fluidly communicated with the fragrance cartridge. This causes the fragrance that is absorbed in the fragrance cartridge to be released into the steam in the steam channel, which is then vented onto the article to be steamed to impart the fragrance thereto. Therefore, the user is able to easily and reliably impart fragrance to the article to be steamed without having to pre-spray the article with fragrance or supply fragrance to the water tank of the steam iron. In addition, since the fragrance cartridge is received in the sole plate, which is heated, heat from the sole plate will encourage evaporation of the fragrance from the fragrance cartridge such that more fragrance is imparted to the steam in the steam channel. Furthermore, the fragrance cartridge being located in the sole plate provides the advantage that the user is easily able to access the fragrance cartridge when the steam iron is located on its base. Therefore, replenishing the amount of fragrance in the fragrance cartridge is simplified.
[0008] In use, the user may supply fragrance to the fragrance cartridge. Upon operation of the steam iron, steam flows along the steam channel and is fluidly communicated with the fragrance cartridge such that fragrance is imparted to the steam which is then vented onto the article to be steamed. Therefore, the user is able to easily and reliably impart fragrance to the article to be steamed without having to pre-spray the article with fragrance or supply fragrance to the water tank of the steam iron. In addition, since the fragrance cartridge is received in the sole plate, which is heated, heat from the sole plate will encourage evaporation of the fragrance from the fragrance cartridge such that more fragrance is imparted to the steam in the steam. Furthermore, the user is able to easily access the fragrance cartridge when the steam iron is located on its base. Therefore, replenishing the amount of fragrance in the fragrance cartridge is simplified.
[0009] The aperture may be circular with a diameter of between 5 mm-10 mm. The aperture may comprise a screw thread adapted to cooperate with a screw thread formed in the fragrance cartridge.
[0010] The aperture may extend between the steam channel and the ironing surface in the proximity of where steam enters the steam channel. This allows for the steam to have a fragrance imparted to it when it enters the steam channel such that there is more time for the fragrance to be spread evenly throughout the steam before the steam exits the sole plate via the vents.
[0011] The fragrance cartridge may comprise a fragrance receiving element and a holder to hold said fragrance receiving element.
[0012] In one embodiment, the fragrance receiving element extends through the holder from the steam channel to enable it to be filled with liquid fragrance without removing the holder from the aperture. This allows for easy refilling of the fragrance cartridge since the user is able to supply fragrance to the porous fragrance receiving element without first having to remove the holder from the sole plate.
[0013] In one embodiment, the holder comprises a recess to receive the fragrance receiving element and wherein the recess only extends partially through the holder such that the fragrance receiving element extends partially through the holder and is inaccessible from the ironing surface when the fragrance cartridge is received in the aperture. Therefore, the holder forms a barrier between the flavour receiving element and the article to be steamed such that direct contact is prevented. Therefore, the chance of fragrance being leaked onto the article to be steamed is reduced.
[0014] The fragrance receiving element may be adapted to protrude into the steam channel. This increases the surface area of the fragrance receiving element that is in contact with the steam in the steam channel so that the amount of fragrance imparted to the steam is increased.
[0015] The fragrance receiving element may be made from a porous material.
[0016] In one embodiment, the holder lies flush with the ironing surface. Therefore, the holder is prevented from snagging on the article to be steamed when the ironing surface is moved over the surface of the article to be ironed.
[0017] In one embodiment, the holder is removably secured within the aperture in the sole plate. Therefore, the fragrance receiving element can easily be replaced if faulty or substituted with a fragrance receiving element that is imparted with a different fragrance.
[0018] The holder may be manually removable from the sole plate by movement of the holder relative to the sole plate. Therefore, the user can remove the holder to supply fragrance to the fragrance receiving element and can easily repair and/or replace the holder and fragrance receiving element.
[0019] The holder may be manually removable from the sole plate without use of a separate tool. This allows for the user to easily remove the holder to replace the fragrance receiving element or to supply fragrance thereto.
[0020] According to another aspect of the invention, there is provided a method of imparting a fragrance to steam intended to be sprayed over garments during ironing by a steam iron having a sole plate, said sole plate comprising a steam channel for the passage of steam, an ironing surface, vents for the passage of steam between the steam channel and the ironing surface, and an aperture extending between the steam channel and the ironing surface, the method comprising the steps of: disposing a fragrance cartridge in said aperture such that it extends into the steam channel to diffuse fragrance in the steam channel and is flush with the ironing surface; and, passing steam into the steam channel.
[0021] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
[0023] FIG. 1 is a schematic cross-sectional side view of a steam iron according to an embodiment of the invention;
[0024] FIG. 2 is a perspective view of the steam iron of FIG. 1 , with a holder removed from a sole plate of the steam iron;
[0025] FIG. 3 is a schematic cross-sectional side view of a steam iron according to an alternative embodiment of the invention; and,
[0026] FIG. 4 is a schematic cross-sectional side view of a steam iron according to an alternative embodiment of the invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0027] Referring now to FIGS. 1 and 2 , a steam iron 1 according to an embodiment of the invention is shown. The steam iron 1 comprises a body 2 and a sole plate 3 . The steam iron 1 is configured to apply steam to an article to be ironed, such as a garment, through a plurality of steam vents 4 in the sole plate 3 .
[0028] The steam iron 1 includes a steam generator 5 for generating steam. The steam generator 5 is of a conventional arrangement known to a person skilled in the art, for example comprising a pump (not shown) that supplies liquid water from a water tank (not shown) to a boiler (not shown). The boiler is configured to heat water within the boiler to make steam.
[0029] A steam channel 6 fluidly communicates the steam generator 5 with the plurality of steam vents 4 in the sole plate 3 . Therefore, steam is able to flow from the steam generator 5 , along the steam channel 6 , and out of the steam vents 4 to act on the garment to be steamed.
[0030] The steam iron 1 further comprises a fragrance cartridge 7 . The fragrance cartridge 7 comprises a holder 7 A and a fragrance receiving element 8 . The holder 7 A comprises a recess 13 that is configured to receive the fragrance receiving element 8 such that an end of the fragrance receiving element 8 is securely contained in the holder 7 A.
[0031] The sole plate 3 comprises an aperture 9 that extends through the thickness of the sole plate 3 . The aperture 9 is configured to receive the holder 7 A. The aperture 9 comprises a screw thread 11 that is configured to engage with a screw thread 12 of the holder 7 A such that the fragrance cartridge 7 can be removably screwed into the aperture 9 of the sole plate 3 .
[0032] The aperture 9 is circular and has a diameter of between 5-10 mm and the holder 7 A is circular and has a corresponding diameter to fit snugly into the aperture 9 . However, it will be recognised that in alternate embodiments the aperture 9 and holder 7 A may be another shape and/or size.
[0033] The fragrance receiving element 8 may comprise a porous material. In the present embodiment, the porous material comprises foam. However, it should be recognised that the fragrance receiving element 8 may comprise a different porous material for example, cork or fabric.
[0034] In use, the user supplies a few drops of liquid fragrance to the fragrance receiving element 8 . The porous material of the fragrance receiving element 8 absorbs the drops of liquid fragrance. The fragrance cartridge 7 is then screwed into the aperture 9 . The fragrance may comprise, for example, an essential oil or perfume.
[0035] The sole plate 3 comprises a contact surface 10 that abuts the garment to be steamed. When the fragrance cartridge 7 is screwed into the aperture 9 in the sole plate 3 , the holder 7 A does not extend past the contact surface 10 and instead a surface of the holder 7 A sits flush to the contact surface 10 . This configuration prevents the holder 7 A from snagging on the garment being steamed when the contact surface 10 of the sole plate 3 is moved over the surface of the garment to be steamed.
[0036] An end of the fragrance receiving element 8 extends into the steam channel 6 when the fragrance cartridge 7 is screwed into the aperture 9 of the sole plate 3 . Therefore, upon operation of the steam generator 5 , steam flows along the steam channel 6 and is fluidly communicated with the fragrance receiving element 8 . This causes the fragrance that is absorbed in the fragrance receiving element 8 to be released into the steam in the steam channel 6 . The steam is then vented through the plurality of steam vents 4 and onto the garment to be steamed such that the fragrance is imparted onto the garment.
[0037] The fragrance cartridge 7 can be unscrewed from the aperture 9 in the sole plate 3 to allow the user to access the fragrance receiving element 8 . Therefore, the user can easily replenish the amount of fragrance absorbed in the fragrance receiving element 8 . In addition, the fragrance receiving element 8 can be substituted with another fragrance receiving element (now shown) that is used to absorb a different fragrance. Therefore, mixing of different fragrances is prevented and there is no need for all of the fragrance in the fragrance receiving element 8 to be depleted before a different fragrance is used.
[0038] The fragrance cartridge 7 can easily be manually unscrewed from the aperture 9 without the need for a separate tool. The holder 7 A comprises a slot 7 B that is on the opposite side of the holder 7 A to the fragrance receiving element 8 . The slot 7 B is accessible by the user when the holder 7 A is received in the aperture 9 in the sole plate 3 . Therefore, a user can insert their fingernail into the slot 7 B to unscrew the holder 7 A to remove the fragrance cartridge 7 from the aperture 9 . In an alternate embodiment (not shown), the slot 7 B is omitted and is replaced with one or more projections that can be gripped by the user to unscrew the holder.
[0039] Referring now to FIG. 3 , a steam iron 1 according to an alternative embodiment of the invention is shown. The steam iron 1 comprises a body 2 , sole plate 3 , steam generator 5 and steam channel 6 that are similar to those described above in relation to FIGS. 1 and 2 , with like features retaining the same reference numerals. A difference is that the steam iron 1 shown in FIG. 3 comprises a fragrance cartridge 7 that has a holder 7 A with a passage 14 extending through the entire thickness of the holder 7 A. The passage 14 extends from the steam channel 6 to the contact surface 10 of the sole plate 3 .
[0040] The fragrance receiving element 8 is securely received in the passage 14 and extends from the steam channel 6 to the contact surface 10 of the sole plate 3 . A first end 8 A of the fragrance receiving element 8 extends into the steam channel 6 when the holder 7 A is screwed into the aperture 9 of the sole plate 3 to impart fragrance to the steam in the steam channel 6 . The distal second end 8 B of the fragrance receiving element 8 does not protrude from the contact surface 10 of the sole plate 3 and, preferably, is flush with the contact surface 10 . This prevents the holder 7 A and the second end 8 B of the fragrance receiving element 8 from snagging on the garment being steamed when the sole plate 3 is moved over the surface of the garment.
[0041] The user is able to supply drops of liquid fragrance to the fragrance receiving element 8 without first having to remove the fragrance cartridge 7 from the aperture 9 in the sole plate 3 . This is because the second end 8 B of the fragrance receiving element 8 sits flush to the contact surface 10 of the sole plate 3 and so the user is easily able to access the fragrance receiving element 8 to supply fragrance thereto. Thus, the user can replenish the fragrance absorbed in the fragrance receiving element 8 simply by orientating the steam iron 1 such that the sole plate 3 faces upwardly and then supply drops of liquid fragrance onto the exposed second end 8 B of the fragrance receiving element 8 .
[0042] The porous material of the fragrance receiving element 8 facilitates a capillary action which causes the fragrance to move along the fragrance receiving element 8 from the second end 8 B to the first end 8 A thereof. The first end 8 A of the fragrance receiving element 8 protrudes into the steam channel 6 . Therefore, drops of fragrance that are supplied to the second end 8 B of the fragrance receiving element 8 travel along the fragrance receiving element 8 to be fluidly communicated with the steam in the steam channel 6 to impart a fragrance thereto.
[0043] In the embodiments described above, the user is able to unscrew the holder 7 A from the aperture 9 in the sole plate 3 to remove the fragrance receiving element 8 from the fragrance cartridge 7 . Therefore, the fragrance receiving element 8 can easily be replaced if it is broken, or swapped with an alternative fragrance receiving element that is imparted with a different fragrance.
[0044] Referring now to FIG. 4 , a steam iron 1 according to an alternative embodiment of the invention is shown. The steam iron 1 is similar to those described above in relation to FIGS. 1 to 3 , with like features retaining the same reference numerals. A difference is that the steam iron 1 shown in FIG. 4 comprises a steam generator 5 that is located outside of the body 2 of the steam iron 1 . A flexible hose 5 A fluidly communicates the steam generator 5 with the steam channel 6 . In use, steam is supplied from the steam generator 5 to the steam channel 6 via the flexible hose 5 A and is imparted with a fragrance in the manner described above.
[0045] In the above described embodiments the aperture 9 and the holder 7 A each comprise a screw thread 11 , 12 to allow the holder 7 A to be screwed into the aperture 9 such that the fragrance cartridge 7 is releasably secured to the sole plate 3 . However, in alternate embodiments (not shown) the screw threads 11 , 12 are omitted and instead the fragrance cartridge 7 is releasably secured in the aperture 9 in a different manner. For example, the holder 7 A may be releasably clipped into the aperture 9 in the sole plate 3 or releasably secured therein by non-permanent adhesive.
[0046] In the above described embodiments the fragrance cartridge 7 is removable from the aperture 9 is the sole plate 3 to allow for easy replacement of the fragrance receiving element 8 and supply of the fragrance receiving element 8 with fragrance. However, in an alternate embodiment (now shown) the fragrance cartridge 7 is permanently fixed in the aperture 9 of the sole plate 3 . For example, the holder 7 A may be adhered to the sole plate 3 by permanent adhesive.
[0047] Although in the above described embodiments the fragrance receiving element 8 is removable from the holder 7 A, to allow for easy maintenance and for the fragrance receiving element 8 to be swapped with another that is used to absorb a different fragrance, in alternate embodiments (not shown) the fragrance receiving element is permanently secured to the holder.
[0048] In the above described embodiments the user supplies drops of liquefied fragrance, for example perfume or essential oils, to the fragrance receiving element 8 . However, it should be recognised that the fragrance receiving element 8 could alternatively be sprayed with a gaseous fragrance or provided with a solid fragrance, for example powdered fragrance. In another embodiment (not shown), the fragrance receiving element is pre-supplied with a fragrance such that the user does not have to apply fragrance to the fragrance receiving element and instead merely has to secure the fragrance receiving element to the sole plate using the holder.
[0049] The above embodiments as described are only illustrative, and not intended to limit the technique approaches of the present invention. Although the present invention is described in details referring to the preferable embodiments, those skilled in the art will understand that the technique approaches of the present invention can be modified or equally displaced without departing from the spirit and scope of the technique approaches of the present invention, which will also fall into the protective scope of the claims of the present invention. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. Any reference signs in the claims should not be construed as limiting the scope.
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The present application relates to steam iron ( 1 ). The steam iron ( 1 ) comprises a sole plate ( 3 ). The sole plate ( 3 ) has a steam channel ( 6 ) for the passage of steam, an ironing surface ( 10 ), vents ( 4 ) for the passage of steam between the steam channel ( 6 ) and the ironing surface ( 10 ), an aperture ( 9 ) extending between the steam channel ( 6 ) and the ironing surface ( 10 ), and a fragrance cartridge ( 7 ) being received in the aperture ( 9 ) such that it extends into the steam channel ( 6 ) to diffuse fragrance in the steam channel ( 6 ). The aperture ( 9 ) secures the fragrance cartridge ( 10 ) in the sole plate ( 3 ) such that fragrance cartridge ( 7 ) is flush with the ironing surface ( 10 ). The present invention also relates to a fragrance cartridge ( 7 ) and to a method of imparting a fragrance to steam produced by a steam iron ( 1 ).
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BACKGROUND OF THE INVENTION
This invention relates generally to controlling of the direction of drilling a borehole in the earth, for causing that borehole to traverse a desired path within the earth.
Early apparatus and methods used for this purpose employed a device called a whipstock that was lowered into a borehole and oriented to the direction of desired borehole divergence from its initial path. This apparatus had a tapered portion that would force the drill bit to diverge in the oriented direction. Later apparatus and methods were developed that used a down-hole motor, driven by drilling-mud flow or other means. Such motors are typically mounted to the lower end of a bent subassembly such that the longitudinal axis of the motor, and the drilling bit at its lower end, are at a slight angle to the direction of the drill string above the bent subassembly. When it is desired to drill in a generally straight path, the motor may be not activated, if desired, and drill string is continuously rotated. When it is desired to cause the path of the borehole to diverge in a given direction, continuous rotation of the drill string is stopped. Then the drill string, bent subassembly, motor and bit are rotated to position the direction of bend in the bent subassembly in the desired direction of divergence, the upper part of the drill string is held in this position and the down-hole motor is started. This causes the borehole to diverge in the desired and selected direction. Down-hole motors are expensive and have a relatively short life while drilling.
As an alternative to the use of a bent subassembly and a down-hole motor, various other apparatus and methods have been developed for steerable rotary drilling. Most, if not all of these, provide some means of providing a sideways-direction force relative to the lower end of the drill string to cause the path of the drill string to diverge from a straight path.
Three early U.S. Pat. Nos. 4,394,881, 4,635,736 and 5,038,872, disclosed two spaced-apart centralizers that were mounted to a collar by a number of bladders or other flexible elements that were fluid-filled. Fluid passages connected upper bladders to lower bladders such that if an upper was compressed on the low side of the hole, a lower one would receive pressure on the high side of the hole to force the bit down. There were no sensor elements and no gain functions in the system.
Two other rotary steering developments are disclosed in prior patents, referred to as a modulated bias unit, GB 2,259,316 and U.S. Pat. No. 5,520,255, and a control unit, GB 2,257,182, U.S. Pat. Nos. 5,265,682 and 5,695,015. This apparatus is generally described in a Schlumberger brochure, “PowerDrive, The New Direction in Rotary Drilling”.
The modulated bias unit as generally described in the brochure, is firmly attached to the drill string and bit and has piston-like members that can be pushed out to provide side force. The control unit provides control of valving for these pistons that results in cycling the actuators in the modulated bias unit to keep the force acting in a desired spacial direction, as the drill string and bit rotate. The valving for the bias units is controlled by a shaft at the output of the control unit. The shaft is stabilized in space about the rotation axis, but is not however stabilized with respect to level. The attitude of stabilization provides the direction in which the bias unit will push. The control unit basically provides a mechanical control of the bias unit. For example, the Summary in U.S. Pat. No. 5,265,682 states, “The invention also provides a steerable rotary drilling system comprising a roll stabilized instrument assembly having an output control shaft the rotational orientation of which represents a desired direction of steering . . . ”. That patent does not disclose or include a “strapped-down” configuration of sensors. The Background of the Invention states, “With the drill collar rotating, the principle choice is between having the instrument package, including the sensors, fixed to the drill collar and rotating with it, or having the instrument package remain essentially stationary as the drill collar rotates around it (a so-called “roll-stabilized” system).
In U.S. Pat. No. 5,265,682, the use of roll sensors is discussed, as follows: “As previously mentioned, the roll sensors 27 carried by the carrier 12 may comprise a triad of mutually orthogonal linear accelerometers or magnetometers”, and, “In order to stabilize the servo loop there may also be mounted on the carrier 12 an angular accelerometer. The signal from such an accelerometer already has inherent phase advance and can be integrated to give an angular velocity signal which can be mixed with the signals from the roll sensors to provide an output which accurately defines the orientation of the carrier.”
U.S. Pat. No. 5,695,015 has a similar statement about “stabilized” vs. “strapped-down”. In all of these control unit patents, the stabilization torque is obtained by vanes in the mud flow and brakes, either electrical or mechanical. Power generation is disclosed as being from the same vanes.
U.S. Pat. No. 5,803,185, entitled “Steerable Rotary Drilling Systems and Method of Operating Such Systems”, appears to combine one of the earlier bias and control units with additional hardware such that the valving in the control unit can also be used to transmit data to the surface through pressure pulses.
U.S. Pat. No. 5,842,149, entitled “Closed Loop Drilling System”, addresses steerable rotary drilling and other techniques. It shows and mentions “Directional Devices to Correct Drilling Direction”. FIG. 3 shows apparatus adjacent to the bit that can push on the sides. Such apparatus does not appear to be described as stabilized in space. The shaft for the drill bit drive appears centralized, while control elements are described as being in a non-rotating part. For example, the patent states “An inclination device 266 , such as one or more magnetometers and gyroscopes, are preferably disposed on the non-rotating sleeve 262 for determining the inclination of the sleeve 262 ”.
U.S. Pat. No. 5,979,570 discloses an apparatus for selectively controlling, from the surface of the earth, a drilling direction of an inclined wellbore. The apparatus comprises a hollow rotatable mandrel having a concentric longitudinal bore, a single inner eccentric sleeve rotatably coupled about the mandrel and having an eccentric longitudinal bore, an outer housing rotatably coupled around the single inner eccentric sleeve and having an eccentric longitudinal bore with a weighted side adapted to seek the low side of the wellbore, a plurality of stabilizer shoes and a drive means to selectively drive the single inner eccentric sleeve with respect to the outer housing. Since the offset required to provide the desired divergence from the initial wellbore direction is created by the weighted off-center element, this apparatus is only of use in an inclined borehole and is not useful in a vertical, or near-vertical wellbore. Also, the drive means must be activated at the surface of the earth before entry of the drill string into the borehole.
U.S. Pat. Nos. 5,307,885, 5,353,884 and 5,875,859 disclose the use of one or more eccentric cylindrical members to provide for lateral displacement of a section of the drill pipe. Universal joints are used so that the direction of the bit with respect to the drill string axis of the bit can be changed by the eccentric members. The axial load on the drill bit is transferred around the segment having the universal joints through a fixed outer housing. International Application WO 01/04453 A1 discloses an approach very similar to those three patents, but the drill-pipe segment containing the universal joints is replaced by a flexible pipe section that can be directly bent by the eccentric cylindrical member. In these four patents, as well as with the previously-cited approaches using eccentric cylinders, the degree of lateral offset is controlled by differential rotation of the eccentric cylinders about the borehole axis.
All of the above prior disclosures lack the unusual advantages in construction, operation and results of the present invention.
SUMMARY OF THE INVENTION
An important object of the present invention is to provide a simpler and less-costly apparatus for steerable rotary drilling that overcomes shortcomings of prior art apparatus, and is useful in boreholes having any directional path, from vertical to horizontal and beyond, and enables its effective direction control force to be set while the drill string is within the borehole.
Another object of the invention is to provide a “side force” type of apparatus for rotary steerable drilling of a borehole in the earth, wherein a controlled differential displacement is provided between opposed pairs of side force elements that push against the borehole sides as drilling progresses.
Elements of apparatus for steerable rotary drilling of a borehole in the earth comprise:
a) a central portion or mandrel, having a central opening therethrough for the passage of drilling fluids,
b) that central portion having a lower connection suitable for connecting to a drill bit,
c) that central portion also having an upper connection suitable for connecting to a drill string, or other components, above the apparatus,
d) an outer housing surrounding a longitudinal part of the central portion or mandrel,
e) the outer housing having a rotary joint at its upper end for connection to the central portion and having a rotary joint for connection to the central portion so as to permit continuous rotation of the central portion about its longitudinal axis,
f) one or more pairs of radially-extensible, opposed, side-force exerting elements controlled by a differential displacement drive mechanism within the outer housing to provide a side force exerted against the borehole wall,
g) a pair of pistons associated with each pair of radially-extensible opposed side-force elements,
h) one or more displacement transducers associated with each of said pair of pistons,
i) control valves within the outer housing for control of the differential displacement drive mechanism and
j) sensing, control and power supply elements to actuate the control valves so as to steer drilling in any desired direction.
Another object is to provide radially extensible elements configured to be automatically activated whenever there is pressure interior to said mandrel provided by said drilling fluid. Typically there are two pairs of such elements.
A further object is to provide sensing elements in the form of magnetometer, accelerometer, and/or gyroscopic elements.
An added object is to provide apparatus for directionally steering a rotary drilling bit in a borehole, comprising
a) mandrel structure in a drill string above the bit, b) multiple side force exerting elements carried by the mandrel, c) and means for controllably and selectively exerting hydraulic pressure acting to control lateral displacement of said elements for engagement with the borehole wall, d) said means including directional control instrumentation sensitive to displacement or positioning of said elements relative to the borehole, including at least one of the following:
i) a gyroscope ii) an accelerometer iii) a magnetometer.
Such means may advantageous include position transducers carried by said side force exerting elements, and circuitry responsive to outputs of said transducers to control solenoid operated valves that in turn control application of borehole fluid pressure to actuators operatively connected to said side force exerting elements.
These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following specification and drawings, in which:
DRAWING DESCRIPTION
FIG. 1 shows a borehole in cross-section containing a steerable rotary drilling mechanism and also showing a typical desired path change for such a borehole;
FIG. 2 shows cross-sections A, B and C of a prior art device using eccentric cylinders for directional control;
FIG. 2 a shows a longitudinal cross-section of another prior art mechanism having a modulated bias unit;
FIG. 3 is a longitudinal cross-section of a steerable rotary drilling mechanism of the present invention;
FIG. 4 is a schematic diagram of hydraulic control circuits of the present invention;
FIG. 5 shows a block diagram of related measurement, control and power supply equipment used with the steerable rotary drilling mechanism of the present invention.
DETAILED DESCRIPTION
FIG. 1 shows diagrammatically a typical rotary drilling installation of a kind in which the present invention may be used. The bottom hole assembly includes a drill bit 1 and is connected to the lower end of drill string 2 which is rotatably driven from the surface by a rotary table 3 on a drilling platform 4 . The rotary table is driven by a drive motor 5 . Raising and lowering of the drill string, and application of weight-on-bit, is under the control of draw works indicated diagrammatically at 6 .
The bottom hole assembly includes a bearing section 8 for attachment to the drill string 2 that permits rotary motion between the drill string 2 and the steerable section 9 . The outer surface of the steerable section 9 may be held in a fixed non-rotational direction or it may be allowed to rotate slowly as the drill string penetrates into the earth. Internal to the steerable section, a rotary element connects the drill string 2 to the drill bit 1 . Radially-extensible side-force exertion elements 45 are provided at the lower end of the steerable section 9 , that engage the bore wall and provide the side force acting on the bit enabling drilling to progress in any desired direction. The direction in space of the side force is typically controlled by elements within the steerable section 9 .
PRIOR ART
FIG. 2 shows three cross-section views, normal to the borehole axis, of typical prior art deflection mechanisms that tend to bend the drill string to provide lateral deflection of the drill string with respect to an outer housing. Apparatus of this type is generally referred to as “point the bit” types since the axis of rotation of the bit is changed from the axis of rotation of the driving drill string. An outer cylindrical housing 20 contains two eccentric cylinders, the outer eccentric cylinder 21 and the inner eccentric cylinder 22 . Interior to the inner eccentric cylinder 22 is the drill string pipe 23 . The center of the outer cylindrical housing is at 24 . In the left-hand cross-section A, the eccentric cylinders 21 and 22 are positioned with their eccentricities opposite each other so that the drill string pipe 23 is centered on the center of the outer cylindrical housing at 24 . In the center cross-section B, the eccentricities of the eccentric cylinders are aligned and the drill string pipe 23 is displaced as shown below the center of the outer housing at 24 . This orientation of the offset may be rotated around the borehole axis to cause deflection in any desired direction. Further, as shown in the right-hand cross-section C, the magnitude and direction of the offset may be set to any desired magnitude and direction by combination of the angular positions of the two eccentric cylinders.
FIG. 2 a , adapted from U.S. Pat. No. 5,803,185, shows another type of apparatus that is generally referred to as a “side-force” type, since a side force is generated just above the bit to force the bit in the desired direction. The axis of rotation of the bit remains colinear with the axis of rotation of the driving drill string. The bottom hole assembly includes a modulated bias unit 25 to which the drill bit is connected and a roll stabilized control unit (not shown) which controls operation of the bias unit 25 in accordance with an on-board computer program, and/or in accordance with signals transmitted to the control unit from the surface. The bias unit 25 can be controlled to apply a lateral bias to the drill bit in a desired direction so as to control the direction of drilling.
Referring to FIG. 2 a , the bias unit 25 comprises an elongate main body structure provided at its upper end with a threaded pin 26 for connecting the unit to a drill collar, incorporating the roll stabilized control unit, which is in turn connected to the lower end of the drill string. The lower end 27 of the body structure is formed with a socket to receive the threaded pin of the drill bit. Provided around the periphery of the bias unit, towards its lower end, are three equally spaced hydraulic actuators 28 . Each hydraulic actuator 28 is supplied with drilling fluid under pressure through a respective passage 29 under the control of a rotatable disc control valve 30 ′-located in a cavity 31 ′ in the body structure of the bias unit. Drilling fluid delivered under pressure downwardly through the interior of the drill string, in the normal manner, passes into a central passage 32 ′ in the upper part of the bias unit, through a filter 33 ′ consisting of closely spaced longitudinal wires, and through an inlet 34 ′ into the upper end of a vertical multiple choke unit 35 ′ through which the drilling fluid is delivered downwardly at an appropriate pressure to the cavity 31 . The disc control valve 30 is controlled by an axial shaft 36 ′ which is connected by a coupling 37 ′ to the output shaft of the roll stabilized control unit.
PRESENT INVENTION
FIG. 3 shows a longitudinal cross-section of a steerable rotary drilling mechanism that provides lateral force applied at the bottom hole assembly to cause drilling to diverge or proceed in a desired direction. A housing 30 contains elements of the steerable assembly. Interior to the housing is a mandrel 31 with extends longitudinally through the assembly. At the upper end of the mandrel, means 110 are provided for operative connection to a rotary drill string. Interior to the mandrel, mud or other drilling fluids 32 may flow unrestricted toward a drill bit attached to the bit box 47 , seen in FIG. 1 . An upper thrust bearing 33 and associated thrust load spring 34 provide axial and radial support between the housing 30 and the mandrel. Another axial bearing 46 is provided at the lower end 111 of the mandrel just above the bit box. Interior to the mandrel, filter screens 35 provide filtered drilling fluid supplied from mandrel bore 31 a to a rotary hydraulic fluid joint and clean fluid reservoir 36 for control of the apparatus. These items provide a path for clean drilling fluids from the bore of the mandrel 31 to the housing 30 Screens 35 are exposed at 35 a to drilling fluid in the mandrel, and ducts 112 pass clean fluid to 36 .
Space 37 for an electronics and power section is provided in the housing, and a hydraulic control system 38 is provided for the control of the apparatus. Numerals 37 a and 38 a designates these elements in 37 and 38 . Two pistons or rams 39 , 40 at opposite sides of the mandrel axis are controlled by the hydraulic control system 38 . Two or more such pairs may be provided for complete 360° azimuth directional control of steering. Note that in FIG. 3 the elements are shown in a fully-retracted position, prior to the application of any pressure from the drilling fluid. A pair of radially-opposed side-force elements or pads 44 , 45 , later referred to as Pad 1 and Pad 3 respectively, are forced radially outwardly by inclined surfaces, on cam members 41 , 42 as those members are controllably pushed axially by the pistons 39 , 40 as commanded by the control system. These side-force exerting elements engage the nominal borehole wall indicated at 48 . Pads 1 , 2 , 3 and 4 may be provided at 0°, 90°, 180° and 270 azimuth positions relative to the mandrel axis. When the same hydraulic pressure is applied to the two pistons 39 and 40 , both side-force elements or pads 44 and 45 are radially extended symmetrically to engage the borehole wall. When the hydraulic control system provides different pressures in the two opposed pistons, the pads are differentially displaced, to effect drilling at a controlled angle or angles.
It is an important feature of the invention that this differential displacement is accurately controlled. One or more linear displacement transducers are typically provided to sense the linear position of each piston or pad. These transducers may be of suitable type and are shown schematically at 115 and 116 , and at 117 and 118 . They may sense either the axial displacement of the pistons or the radial displacement of the pads. From any of these measurements, the actual pad positions with respect to the housing may be obtained, as by instrumentation at 37 a.
FIG. 3 also shows interengaged cam surfaces 125 and 126 , and 127 and 128 on the piston driven actuators 129 and 130 , and on the pads, to effect outward driving of the pads. Piston cylinders appear at 39 a and at 40 a.
FIG. 4 shows a schematic diagram of one version of the hydraulic control system. A source of filtered fluid at internal drill string pressure is shown at 58 . This internal pressure is designated P 1 . A source of filtered fluid at the borehole annulus pressure outside of the housing 30 is shown at 63 . This external annulus pressure is designate Pa. When the source of drilling fluid pressure, generally mud pumps is not operating, the internal Pressure P 1 and the external annulus pressure Pa will be equal. When such pumps are operating, there will be a substantial pressure drop across the bit resulting from the mud flow through the bit. Thus the internal pressure P 1 may typically be on the order of 300 to 600 p.s.i. higher than the external annulus pressure.
The charge/discharge valve 50 is spring loaded to expose channels 53 , 54 (note high pressure from filtered source 58 is provided each channel and the upper piston 51 ) from internal pressure P 1 to each of the pistons 51 and 51 a . (Note channel 53 is connected to port 57 as is channel 54 to port 56 ). Other pairs of pistons not shown are similarly connected and nominally equally spaced to the pair shown. When the mud pumps are operated, the pressure P 1 at 58 increases and is applied directly to the input channels to the valve controlled pistons. The pressure P 1 is also applied to the upper surface of piston 51 , forcing that piston downward and thus closing off the channel 53 . The rate at which this happens is controlled by the bleed rate valve 51 a which is connected from channel 52 to the port 64 on the external annulus pressure Pa source 63 . This valve may be adjusted to the desired timing for each application circumstance. When the pumps are shut down and P 1 is no longer greater than Pa, the spring-loaded chamber 50 b in the charge/discharge valve 50 will slowly fill and once again open each piston to the Pa pressure. This relieves the charge of pressure P 1 to the pistons allowing the pistons to relax to the retracted position.
A dual valve 59 , 60 is activated by a solenoid or other means for thrust control of piston # 1 39 and relief of piston # 3 40 . Similarly, thrust control of piston # 3 40 and relief of piston # 1 39 is provided by dual valve 61 , 62 . A similar arrangement is provided for each additional pair of pistons of radially opposed pistons in the apparatus. As shown in the figure, channels 54 and 56 would connect to a second pair of pistons.
When drilling is to begin, the pumps turn on to provide drilling fluid pressure, the pistons 51 and 51 a are charged to pressure P 1 and the charge/discharge valves 50 and 50 a slowly compress shutting off the charge/discharge ports of each pad piston 39 and 40 . As pressure builds up on the pistons, 51 and 51 a connecting rods or actuators from the pistons activate the radially-extensible elements or pads outward to engage the borehole wall 48 of FIG. 3 .
Assume for example that the apparatus is in a horizontal hole as seen in FIG. 3 , and that pad # 3 45 is on the low side of the hole and all of the cantilevered weight of the bottom hole assembly is resting on pad # 3 . Clearly, pads # 1 , # 2 (not shown) and # 4 (not shown) with no weight on them will expand to full gauge of the borehole. Assume that it is intended to drill straight ahead. This requires that the radial extension of all pads be the same and that the bit is centered in the borehole. Position transducers are typically provided on each of the pistons to provide signals as to the actual position of each piston and therefore equivalently for each pad. With respect to the opposing pistons shown, these signals are subtracted to provide an error signal that opens valves 61 , 62 so as to force pad # 1 to retract and pad # 3 to extend. When they reach equivalent positions, the error signal is reduced and the drill bit is centered in the borehole parallel to the axes of the pair of pistons. Similarly, but not shown, a second pair of pads # 2 and # 4 would equalize their extension. The transducers may comprise one of the following: gyroscope, magnetometer, and accelerometer.
If it is desired to build up the angle of the borehole, a command signal at 131 is sent to the control system, for example to solenoids, that will operate valves 61 , 62 so as to cause hydraulic piston activation to extend pad # 3 to a greater amount and retract pad # 1 by an equal amount. This places the drill bit above the centerline of the borehole and thus causes the direction of the hole to move upward. Similarly, if it is desired to drop the angle of the borehole, the opposite actions would be commanded. The same procedure can be used with a second pair of pads to cause the borehole direction to move left or right. In all of these actions, the opposed pads of each pair maintain their average radial position and individually have a differential displacement. This controlled action results in the pads continually engaging the borehole wall and stabilizing the orientation of the bit in the borehole for most efficient drilling.
FIG. 5 shows a block diagram of related measurement, control and power supply equipment typical of such elements used with the present invention. The main blocks are a hydraulic control box 38 , a command box 86 , a sensor box 85 , a power supply 84 and a primary power source 83 . Connections 71 to 78 represent hydraulic lines to each end of four piston cylinders. Connections 89 to 92 represent displacement signals from four pistons or pads. Inputs 87 and 88 represent inputs of the internal drilling fluid pressure P 1 and the annulus drilling fluid pressure Pa. Sensors for these pressures may be of any suitable type. The command box 86 accepts inputs 79 from other equipment to provide either discrete directional commands or a general desired pathway for the borehole. Based on other inputs 81 from the sensor box and power 95 from the power supply, the command box sends by line 80 commands for the positioning of each of the pistons to the hydraulic control box which uses such commands to carry out the operations described above. The sensor box 85 contains all of the sensors that may be desired or needed to control the apparatus. Such sensors may include one or more accelerometers, one or more magnetometers, one or more gyroscopes, various logging sensors and/or various drilling-condition sensors. The power supply box provide any needed regulation, secondary power conversions and distribution of secondary of electrical power. The primary power supply may be batteries or a generator powered by the drilling fluid flow.
It will be clear to those skilled in the art, that pairs of radially-extensible side force elements or pads can be replaced by any suitable odd number of such elements. For example, three such elements may be used and equivalent commands for pairs of elements can then be resolved into the three directions of operations of such elements.
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An apparatus for steerable rotary drilling of a borehole having a wall in the earth comprising a mandrel having a central opening there through for the passage of drilling fluids. The mandrel having a lower connection for operatively connecting to a drill bit structure and an upper connection for operatively connecting to a drill string above said apparatus. The mandrel further having an intermediate portion, an outer housing surrounding longitudinal extent of the mandrel intermediate portion, a differential displacement drive within the outer housing, one or more pairs of radially-extensible, opposed side-force exerting elements controlled by the differential displacement drive to provide for side force exertion against the borehole wall.
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BACKGROUND
[0001] Ion implantation is a standard technique for introducing conductivity-altering impurities into a workpiece. A desired impurity material is ionized in an ion source, the ions are accelerated to form an ion beam of prescribed energy, and the ion beam is directed at the surface of the workpiece. The energetic ions in the beam penetrate into the bulk of the workpiece material and are embedded into the crystalline lattice of the workpiece material to form a region of desired conductivity.
[0002] Solar cells are one example of a device that uses silicon workpieces. Any reduced cost to the manufacture or production of high-performance solar cells or any efficiency improvement to high-performance solar cells would have a positive impact on the implementation of solar cells worldwide. This will enable the wider availability of this clean energy technology.
[0003] A semiconductor solar cell is a simple device having an in-built electric field that separates the charge carriers generated through the absorption of photons in the semiconductor material. This electric field is typically created through the formation of a p-n junction (diode) which is created by differential doping of the semiconductor material. Doping a part of the semiconductor substrate (e.g. surface region) with impurities of opposite polarity forms a p-n junction that may be used as a photovoltaic device converting light into electricity.
[0004] FIG. 1 shows a cross section of a representative solar cell 100 , where the p-n junction 120 is located away from the illuminated surface. Photons 10 enter the solar cell 100 through the top (or illuminated) surface, as signified by the arrows. These photons pass through an anti-reflective coating 104 , designed to maximize the number of photons that penetrate the substrate 100 and minimize those that are reflected away from the substrate. The ARC 104 may be comprised of an SiN x layer. Beneath the ARC 104 may be a passivation layer 103 , which may be composed of silicon dioxide. Of course, other dielectrics may be used. On the back side of the solar cell 100 are an aluminum emitter region 106 and an aluminum layer 107 . Such a design may be referred to as an Al back emitter cell in one instance.
[0005] Internally, the solar cell 100 is formed so as to have a p-n junction 120 . This junction is shown as being substantially parallel to the bottom surface of the solar cell 100 , although there are other implementations where the junction may not be parallel to the surface. In some embodiments, the solar cell 100 is fabricated using an n-type substrate 101 . The photons 10 enter the solar cell 100 through the n+ doped region, also known as the front surface field (FSF) 102 . The photons with sufficient energy (above the bandgap of the semiconductor) are able to promote an electron within the semiconductor material's valence band to the conduction band. Associated with this free electron is a corresponding positively charged hole in the valence band. In order to generate a photocurrent that can drive an external load, these electron-hole (e-h) pairs need to be separated. This is done through the built-in electric field at the p-n junction 120 . Thus, any e-h pairs that are generated in the depletion region of the p-n junction 120 get separated, as are any other minority carriers that diffuse to the depletion region of the device. Since a majority of the incident photons 10 are absorbed in near surface regions of the solar cell 100 , the minority carriers generated in the emitter need to diffuse to the depletion region and get swept across to the other side.
[0006] Some photons 10 pass through the front surface field 102 and enter the p-type emitter 106 . These photons 10 can then excite electrons within the p-type emitter 106 , which are free to move into the front surface field 102 . The associated holes remain in the emitter 106 . As a result of the charge separation caused by the presence of this p-n junction 120 , the extra carriers (electrons and holes) generated by the photons 10 can then be used to drive an external load to complete the circuit.
[0007] By externally connecting the base through the front surface field 102 to the emitter 106 through an external load, it is possible to conduct current and therefore provide power. To achieve this, contacts 105 , typically metallic and in some embodiments silver, are placed on the outer surface of the front surface field 102 .
[0008] Several parameters affect the efficiency of a solar cell. For example, any carriers that are generated, but recombine before reaching the p-n junction, negatively impact the performance of the cell. Therefore, there is a need in the art for an improved solar cell to help maximize the number of minority carriers that are swept across the p-n junction, thereby maximizing the energy that can be produced from incident photons.
SUMMARY
[0009] An improved solar cell is disclosed. To create the internal p-n junction, one surface of the substrate is implanted with ions. After the implantation, the substrate is thermally treated. The thermal process distributes the dopant throughout the substrate, while drawing defects closer to the surface. The uppermost portion of the surface is then removed, thereby eliminating that portion of the substrate where most of the defects reside. The lower defect concentration reduces recombination and improves efficiency of the solar cell, while minimally impacting the dopant concentration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] For a better understanding of the present disclosure, reference is made to the accompanying drawings, which are incorporated herein by reference and in which:
[0011] FIG. 1 is a cross-sectional side view of a solar cell of the prior art;
[0012] FIG. 2 is a graph showing the effects of varying implant energy, anneal time and anneal temperature on defect concentration;
[0013] FIG. 3 is a graph showing defect concentration versus depth for boron implants of different implant energies;
[0014] FIG. 4 is a graph showing dopant concentration versus depth for boron implants of different implant energies; and
[0015] FIG. 5 illustrates a manufacturing sequence.
DETAILED DESCRIPTION
[0016] The embodiments of the solar cell are described herein in connection with an ion implanter. Beamline ion implanters, plasma doping ion implanters, or flood ion implanters may be used. In addition, other implant systems may be used. For example, an ion implanter without mass analysis or a plasma tool that focuses ions by modifying the plasma sheath may also be used. An ion beam that is focused to only implant specific portions of the solar cell, or grid-focused plasma systems can also be used for the embodiments disclosed herein. However, the gaseous diffusion, furnace diffusion, laser doping, other plasma processing tools, or other methods known to those skilled in the art may be used. In addition, while implant is described, deposition of the doped layers also can be performed. Also, while specific n-type and p-type dopants are listed, other n-type or p-type dopants may be used instead and the embodiments herein are not limited solely to the dopant listed. Thus, the invention is not limited to the specific embodiments described below.
[0017] One method used to form the p-n junctions described above is the use of ion implantation. The introduction of p-type dopants to one surface of an n-type substrate creates the internal p-n junction needed for the solar cell. For example, referring to FIG. 1 , the emitter 106 may be formed through ion implantation of p-type dopants, such as boron. In addition, the FSF 102 may be created by implanting n-type dopants, such as phosphorus into the opposite surface of the substrate.
[0018] It is well known that the implantation of ions into crystalline silicon causes defects, such as vacancies and interstitials. Vacancies are crystal lattice points unoccupied by an atom. This is typically caused when an ion collides with an atom located in the crystal lattice, resulting in transfer of a significant amount of energy to the atom, allowing it to leave its crystal site. Interstitials result when these displaced atoms, or the implanted ions, come to rest in the solid, but do not find a vacant space in the lattice in which to reside. These point defects can migrate and cluster with each other, resulting in dislocation loops and other defects.
[0019] To remove these defects, it is common to perform a thermal process on the substrate, such as an anneal cycle. The temperature of the anneal cycle and its duration both strongly affect the defects which remain in the substrate. For example, FIG. 2 shows a graph showing the effects of implant energy, anneal temperature and anneal time on defect concentration. This data was based on a boron implant at a dose of 1.5e15 cm −2 .
[0020] The solid triangles represent the defect concentration when the boron implants were performed at an implant energy of 10 kV. Note that for a given anneal temperature, longer duration anneal cycles always result in a reduction of defects. Similarly, an increase in anneal temperature will remove more defects for a fixed duration. Thus, a high temperature 1100° C. anneal, performed for 160 minutes results in a four order of magnitude reduction in the defect concentration for an implant energy of 10 kV.
[0021] The hollow triangles represent the defect concentration when the boron implants were performed at an implant energy of 40 kV. In general, higher implant energy results in more defects for a particular anneal temperature and duration. However, the effects of anneal temperature and anneal duration remain very important, as an increase in either or both of these parameters decreases defect concentration. While it is known that anneal processes will help minimize defects, increased anneal times and temperatures often result in higher manufacturing costs and lower production throughput.
[0022] Furthermore, the defect concentration is not uniform as a function of depth. FIG. 3 shows a graph of defect concentration as a function of depth from the surface of the substrate. The hollow circles represent the defect concentration when a boron implant is performed with an implant energy of 10 kV. Following the implant, an anneal cycle is performed at 1050° C. for 80 minutes. From FIG. 3 , it is clear that the concentration of defects is much greater near the surface of the substrate. In fact, at a depth of 200 nm below the surface, the defect concentration decreases about 6 orders of magnitude from its maximum value.
[0023] The solid circles represent the defect concentration for a boron implant performed with an ion implant energy of 40 kV. Although the high defect concentration extends deeper into the substrate, it is noted that the defect concentration at a depth of 500-600 nm is more than 6 orders of magnitude less than the maximum defect concentration.
[0024] FIG. 4 shows a graph of dopant concentration for the two test cases described above. The hollow circles represent the boron implant at an implant energy of 10 kV. It is noted that at a depth of about 800 nm, the dopant concentration is still greater than 1E18, and at a depth of about 1000 nm, the dopant concentration is still greater than 1E17. Similarly, the solid circles represent the boron implant at an implant energy of 40 kV. It is noted that at a depth of about 1000 nm, the dopant concentration is still greater than 1E18, and at a depth of about 1200 nm, the dopant concentration is till greater than 1E17.
[0025] Comparing the graphs of FIG. 3 and FIG. 4 , the depth profiles are very different. Specifically, the dopant concentration profile, shown in FIG. 4 , decays much more slowly as a function of depth than the defect concentration profile, shown in FIG. 3 . In other words, with respect to the lower energy implant, the depth profile from 200 nm to 1000 nm has a defect concentration of less than 1E6, while having a dopant concentration of at least 1E17. Similarly, with respect to the higher energy implant, the depth profile from about 500 nm to 1200 nm also has a defect concentration of less than 1E6, while having a dopant concentration of at least 1E17.
[0026] Thus, by removing a portion of the substrate near the surface, the defect concentration can be dramatically reduced, while having a negligible affect on dopant concentration of the substrate.
[0027] FIG. 5 shows one embodiment of a manufacturing process. First the substrate is implanted with a dopant, such as boron, as shown in step 500 . The substrate is then thermally treated to activate the dopants and repair crystal damage, as shown in step 510 . After this step, most of the dopants are electrically active, and the residual defect concentration is similar to that shown in FIG. 3 . After the substrate is implanted with a dopant and thermally treated, a portion of the implanted surface is removed, as shown in step 520 . In one embodiment, the thickness of the substrate material to be removed is related to the implant energy. For example, at lower implant energies, a shallower thickness may be excised. At higher implants, a greater thickness of material must be removed to eliminate the majority of the defects. In some embodiments, a thickness of between 100 nm and 600 nm is removed. In other embodiments, a fixed thickness of substrate material is removed, independent of implant energy. After the defect removal step is performed, the cell continues with downstream processing (Step 530 ) which may include passivation, metallization, or other appropriate processing steps.
[0028] This material can be removed using any of several methods, including but not limited to wet chemical etching, dry etching (i.e. plasma etching), sputtering or oxidation, whereby the substrate is subjected to an oxidizing environment, and the surface layer is consumed by the oxidation.
[0029] While this disclosure describes the defects and dopant concentration with respect to boron, the disclosure is not limited to this embodiment. In fact, similar graphs are possible using other p-type dopants, including Type III elements and molecular ions containing Type III elements, such as BF 2 . In addition, similar graphs are possible using n-type dopants, including Type V elements and molecular ions containing Type V elements, such as PH 3 . In fact, any p-type or n-type layers in a solar cell embodiment may be formed using ion implantation. Therefore, the method described herein can be used when forming the emitter 106 or the FSF 102 .
[0030] In some solar cell embodiments, there may be additional doped regions. For example, some solar cells utilize selective emitters and selective front surface fields to enhance the attachment to the metal contact. In addition, interdigitated back contact (IBC) solar cells are front surface fields and back surface fields which may be implanted using selective or patterned implants. Unlike the regions described above, these fields are positioned in only a portion of the surface, and are therefore implanted using a patterned or selective implant. In these embodiments, the doped regions are created by using a mask, such as a shadow mask which is placed between the substrate and the ion beam, as shown in step 500 . This mask selectively allows ions to reach and implant only certain portions of the substrate. After the implantation is completed, a thermal process (step 510 ) is performed to activate the dopant and repair the damage caused by the implant process. After the thermal process, the material removal process (step 520 ) is used to remove a thickness from the substrate, including those regions which were not implanted by the patterned implant. In some embodiments, the material removal process is followed by a downstream process, as shown in step 530 . This may be performed to create contacts, such as metal fingers for the FSF or emitter.
[0031] Thus, the ion implantation of step 500 may be selective or blanket depending on the particular design of the p-type or n-type region. For example, as described above, selective emitters and selective front side field regions may be created using a selective or patterned ion implantation. Emitter 106 and front side field 102 may be created using blanket implants.
[0032] In one embodiment, one surface of an n-type substrate is implanted with boron ions to create a p-type emitter. The opposite surface may optionally be implanted with an n-type dopant, such as a Group V element, to create an n-type front surface field. Following these implants, an anneal cycle may be performed to minimize the damage caused in the substrate. After the anneal process is complete, the substrate is then exposed to a material removal process, such as those described above. This material removal process may be performed sequentially on the two surfaces. In another embodiment, the material removal process is performed on both surfaces simultaneously. The amount of material removed may be related to the implant energy of the implant, or may be a fixed predetermined amount, such as 200 nm.
[0033] In another embodiment, ion implantation is used to form selective emitters on which the metal contacts are applied. In many embodiments, this is a selective, or patterned implant, performed using a mask, such as a shadow mask, as shown in step 500 . Following the ion implantation and subsequent anneal cycle (step 510 ), material from the entire surface of the substrate can be removed, including the regions which were not implanted (step 520 ).
[0034] While the disclosure describes the use of anneal of a method to reduce defects, it is understood that any thermal process may be used to reduce defects in the implanted substrate.
[0035] The present disclosure is not to be limited in scope by the specific embodiments described herein. Indeed, other various embodiments of and modifications to the present disclosure, in addition to those described herein, will be apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings. Thus, such other embodiments and modifications are intended to fall within the scope of the present disclosure. Furthermore, although the present disclosure has been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in view of the full breadth and spirit of the present disclosure as described herein.
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An improved solar cell is disclosed. To create the internal p-n junction, one surface of the substrate is implanted with ions. After the implantation, the substrate is thermally treated. The thermal process distributes the dopant throughout the substrate, while repairing crystal damage caused by implantation. After the thermal process, residual crystal damage may remain, which adversely impacts solar cell efficiency. In order to further reduce the residual damage, the uppermost portion of the surface is then removed, thereby eliminating that portion of the substrate where most of the defects reside. The lower defect concentration reduces recombination and improves efficiency of the solar cell.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to a method for producing sintered cadmium negative electrode for use in nickel-cadmium storage batteries.
[0002] Cadmium negative electrodes for use in nickel-cadmium storage batteries known heretofore are classified into sintered negative electrodes and non-sintered negative electrodes. A sintered negative electrode is produced by filling a nickel sintered substrate, which is prepared by sintering nickel powder, with a negative active material made of cadmium oxide or cadmium hydroxide. On the other hand, a non-sintered negative electrode is produced by first preparing a paste by kneading a negative active material comprising cadmium oxide or cadmium hydroxide with synthetic fibers, glue material (binder), etc., and then coating and adhering the resulting paste to an electrically conductive core body (substrate) such as a punching metal and the like.
[0003] In the negative electrodes above, a sintered negative electrode exhibits high reactivity, high charge and discharge efficiency, and excellent properties in absorbing gaseous oxygen, because the negative active material is brought into direct contact with the nickel sintered substrate having excellent electric conductivity. The sintered negative electrode of this type is produced by repeating, for several times, a sequence of operation comprising immersing the nickel sintered substrate in an aqueous cadmium nitrate solution, drying, and converting the resulting product into cadmium hydroxide in an alkaline aqueous solution. In this manner, a sintered substrate filled with a predetermined quantity of negative active material (cadmium hydroxide) can be obtained.
[0004] However, the as-prepared sintered substrate filled with a predetermined quantity of cadmium hydroxide not only is still low in activity of the active material, but also contains impurities such as nitrate groups in the electrode plate, which badly influences the cell characteristics. Hence, the cadmium negative electrode filled with the active material requires chemical conversion treatment. Such a chemical conversion treatment comprises, in general, charging and discharging the cadmium negative electrode filled with the active material in an alkaline aqueous solution for one to several times. However, a chemical conversion treatment by charging and discharging led to a problem of decreasing the production efficiency, because it increased not only the process steps, but also the time duration of treatment.
[0005] Accordingly, a method for removing impurities such as nitrate groups by applying heat treatment to the cadmium negative electrode after filling it with an active material was proposed in, for instance, JP-A-61-85772 and JP-A-62-115662. Since the method proposed in JP-A-61-85772 and JP-A-62-115662 simply requires the cadmium negative electrode filled with the active material to be heat treated at a temperature of 200° C. or higher under an inert gas atmosphere, it enables improving the productivity of the cadmium negative electrode of this type; i.e., it allows removal of the impurity in less process steps and in a shorter period of time, and is thereby suitable for continuous treatment.
[0006] In the cadmium negative electrode of the type above, however, positive electrode control (i.e., controlling the capacity of the positive active material lower than the capacity of the negative active material) should be maintained. Accordingly, a pre-charging step for imparting discharge reserve to the cadmium negative electrode after filling it with the active material is provided. Hence, even in the method proposed in JP-A-61-85772 and JP-A-62-115662 above, pre-charging for imparting the discharge reserve must be carried out after the heat treatment.
[0007] In case the cadmium negative electrode is immersed in an alkaline aqueous solution for pre-charging, cadmium oxide generated by heat treatment undergoes hydration to generate cadmium hydroxide. However, since cadmium hydroxide thus generates is low in electrochemical activity, there occurred a problem that the pre-charging time must be taken longer to achieve the necessary discharge reserve by pre-charging. Since a longer pre-charging time increases the amount of charge, this led to a problem of making low-cost production unfeasible. Furthermore, since the pre-charging time is also elongated, there occurred another problem that the production efficiency is lowered due to the increase in production time. Moreover, in case the pre-charging time is shortened in order to reduce the production time, it resulted in insufficient amount of discharge reserve, and caused a problem of poor cycle characteristics.
[0008] In the light of such circumstances, in JP-A-11-273669 was proposed a method comprising adding polyvinyl pyrrolidone of relatively low degree of polymerization, which is excellent in charge-discharge characteristics, into cadmium oxide active material, such that the charge acceptance of the cadmium negative electrode should be improved. However, this method only improves the inferior charge acceptance of the polyvinyl pyrrolidone of relatively low degree of polymerization to a level well comparable to that of a known cadmium negative electrode. Further, there was found another problem that, although polyvinyl pyrrolidone was effective on improving discharge characteristics, no effect was discernible on improving the charge characteristics.
[0009] On the other hand, in Japanese Patent No. 2567672 is proposed a method comprising firing a cadmium negative electrode filled with an active material at a temperature of 200° C. or higher to convert the active material into cadmium oxide, and then adding a polysaccharide or a derivative thereof having a polymerization degree of 320 or higher. In case of the cadmium negative electrode proposed in Japanese Patent No. 2567672, the active material is added in the state of cadmium oxide having a smaller volume. Thus, since a larger amount of polysaccharide can be added to the electrode plate as compared to a case of adding in the state of cadmium hydroxide, the degradation in characteristics can be suppressed at the charge-discharge cycles; furthermore, by thus performing chemical conversion by charging and discharging after the addition, the utilization factor can be elevated as compared with an electrode plate to which the polysaccharide is added after the chemical conversion. However, the use of a polysaccharide with a polymerization degree of 320 or higher resulted in the formation of a stubborn polymer film, and this film functioned as a resistance on charging and discharging. Thus, this led to a problem of reducing, in particular, the operation voltage on discharge.
SUMMARY OF THE INVENTION
[0010] In the light of such circumstances, the invention has been made to overcome the problems enumerated above, and an object thereof is to provide a method for producing a cadmium negative electrode having excellent cycle characteristics, without impairing the production efficiency even in case the impurities incorporated during filling the active material should be removed by heat treatment.
[0011] In order to achieve the object above, the method for producing sintered cadmium negative electrode according to the invention comprises: an active material filling step comprising filling the nickel sintered substrate with an active material based on cadmium hydroxide to obtain an active material filled electrode plate; a heating step comprising heating the active material filled electrode plate to change at least a part of the thus filled active material based on cadmium hydroxide into cadmium oxide; a polyvinyl alcohol adding step comprising adding polyvinyl alcohol into the active material filled electrode plate through the heating step; and a hydration step comprising hydrating the active material filled electrode plate added with polyvinyl alcohol (i.e., a step comprising immersing the electrode plate in an alkaline solution to convert cadmium oxide into cadmium hydroxide).
[0012] In case the electrode plate filled with the active material is subjected to heat treatment, most of the filled cadmium hydroxide (Cd(OH) 2 ) is converted into cadmium oxide, and by immersion in an aqueous alkaline solution in the subsequent hydration step, it is hydrated and re-converted into cadmium hydroxide. The cadmium hydroxide thus generated by hydration is β-type cadmium hydroxide having a smaller surface area. However, in case polyvinyl alcohol (PVA) is added to the heat-treated electrode plate prior to the hydration, polyvinyl alcohol reacts with the active material (cadmium hydroxide) on hydration as to generate γ-type cadmium hydroxide having an acicular crystal structure and a larger surface area. Since cadmium hydroxide having a larger surface area results in an improved charge acceptance, the quantity of charged electricity can be reduced at pre-charging. Accordingly, this enables cadmium negative electrode with lower quantity of charged electricity and having excellent cycle characteristics.
[0013] Since the temperature at which cadmium hydroxide converts into cadmium oxide is ca. 180° C., the temperature for heat treatment should be set to 180° C. or higher.
[0014] Furthermore, in case the amount for converting cadmium hydroxide into cadmium oxide is less than 70% by mass with respect to the total mass of the active material as reduced to cadmium hydroxide, impurities such as nitrate groups in the active material remains insufficiently decomposed. Such impurities negatively influences when assembled into a cell as to increase self discharge. Hence, the amount converted into cadmium oxide must account for 70% by mass or higher with respect to the mass of total active material as reduced to cadmium hydroxide.
[0015] In case the amount of adding polyvinyl alcohol (PVA) is too small, polyvinyl alcohol tends to insufficiently react with the active material, and this results in an insufficient formation of γ-type cadmium hydroxide having an acicular crystal structure and a larger surface area.
[0016] On the other hand, polyvinyl alcohol added in excess inhibits the charge-discharge reaction. Accordingly, the amount of adding polyvinyl alcohol is preferably confined as such that it may fall in a range of from 0.03 to 10% by mass with respect to the mass of the total active material as reduced to cadmium hydroxide.
[0017] Furthermore, in case the polymerization degree of polyvinyl alcohol (PVA) added prior to hydration should exceed 2000, the coating film of polyvinyl alcohol (PVA) that is formed on the surface of the negative electrode becomes too stubborn as to inhibit the charge-discharge reaction. Thus, preferably, polyvinyl alcohol (PVA) having a polymerization degree of 2000 or lower is added into the cadmium negative electrode prior to hydration.
BRIEF DESCRIPTION OF THE DRAWING
[0018] [0018]FIG. 1 is a diagram showing the relation between the cycle repetition times and cell capacity in an assembled nickel-cadmium storage battery.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] An embodiment for producing a sintered cadmium negative electrode according to the invention is described below in the order of active material filling step, heating step, PVA adding step, and hydration and pre-charging step.
1. Example
[0020] (1) Active Material Filling Step
[0021] The surface of an electrically conductive core body made from punched metal was coated with nickel slurry, and the resulting product was sintered under a reducing atmosphere to obtain a nickel sintered substrate (having a porosity of about 80%). Then, the nickel sintered substrate was immersed in an impregnating solution containing cadmium nitrate as the principal component thereof, and, after drying, it was subjected to alkali treatment fill the pores of the nickel sintered substrate with cadmium hydroxide. The entire operation (chemical impregnation method) was repeated for predetermined times to fill the pores of the nickel sintered substrate with a predetermined amount of cadmium active material (a negative active material based on cadmium hydroxide). Thus was obtained an active material filled electrode plate.
[0022] (2) Heating Step
[0023] Then, the active material filled electrode plate thus obtained was placed inside a heating furnace maintained at a temperature of 180° C., and was subjected to a heat treatment for a predetermined duration of time to thereby convert cadmium hydroxide (Cd(OH) 2 ) filled in the nickel sintered substrate into cadmium oxide (CdO). In this manner, the impurities such as nitrate groups adhered to the active material filled electrode plate were decomposed and removed. In this case, the heating time for the active material filled electrode plate placed in the heating furnace was set to 30 minutes to thereby obtain an active material filled electrode plate containing 99% by mass (denoted as “mass %” hereinafter) of converted cadmium oxide with respect to the total mass of the active material (i.e., the total active material as reduced to cadmium hydroxide). Thus was obtained a heated electrode plate α.
[0024] The fact that converted cadmium oxide accounted for 99 mass % of the total mass of the active material (as reduced to cadmium hydroxide) can be easily confirmed by measuring the masses of the active material filled electrode plate before and after the heat treatment.
[0025] Similarly, a heated electrode plate β containing converted cadmium accounting for 70 mass % of the active material was obtained by controlling the heating time to 18 minutes, a heated electrode plate γ containing converted cadmium accounting for 60 mass % of the active material was obtained by controlling the heating time to 15 minutes, and a heated electrode plate δ containing converted cadmium accounting for 50 mass % of the active material was obtained by controlling the heating time to 12 minutes.
[0026] (3) PVA Adding Step
[0027] Subsequently, each of the heated electrode plates α, β, γ, and δ thus obtained by heat treatment was immersed for a predetermined duration of time into polyvinyl alcohol (PVA: having a polymerization degree of 500; POVAL (trademark) of grade 105, manufactured by Kuraray Co., Ltd.) adjusted to a predetermined concentration, and was dried to add a predetermined amount of polyvinyl alcohol on the surface and to the inside of the active material filled electrode plate. Thus were obtained PVA-added electrode plates.
[0028] More specifically, the heated electrode plate α (containing cadmium oxide accounting for 99 mass % of the active material) was immersed in a 5.0-mass % aqueous PVA solution for a duration of 3 minutes to obtain a PVA-added electrode plate a 1 containing 0.20 mass % of PVA with respect to the amount of active material (hereinafter, the amount of active material is a value reduced to cadmium hydroxide).
[0029] Similarly, a PVA-added electrode plate b 1 containing 0.05 mass % of added PVA was prepared by immersing the heated electrode plate α in a 1.0-mass % aqueous PVA solution for a duration of 3 minutes, and a PVA-added electrode plate c 1 containing 1.00 mass % of added PVA was prepared by immersing the heated electrode plate α in a 10-mass % aqueous PVA solution for a duration of 5 minutes.
[0030] Furthermore, a PVA-added electrode plate d 1 containing 0.03 mass % of added PVA was prepared by immersing the heated electrode plate β (containing cadmium oxide accounting for 70 mass % of the active material) in a 1.0-mass % aqueous PVA solution for a duration of 2 minutes, and a PVA-added electrode plate e 1 containing 1.00 mass % of added PVA was prepared by immersing the heated electrode plate β in a 10-mass % aqueous PVA solution for a duration of 5 minutes.
[0031] Further, the heated electrode plate γ (containing cadmium oxide accounting for 60 mass % of the active material) was immersed in a 5.0-mass % aqueous PVA solution for a duration of 3 minutes to obtain a PVA-added electrode plate f 1 containing 0.20 mass % of PVA with respect to the amount of active material.
[0032] Then, the heated electrode plate δ (containing cadmium oxide accounting for 50 mass % of the active material) was immersed in a 5.0-mass % aqueous PVA solution for a duration of 3 minutes to obtain a PVA-added electrode plate g 1 containing 0.20 mass % of PVA with respect to the amount of active material.
[0033] Furthermore, the heated electrode plate α was immersed in a 0. 5-mass % aqueous PVA solution for a duration of 3 minutes to obtain a PVA-added electrode plate h 1 containing 0.02 mass % of PVA with respect to the amount of active material, and the heated electrode plate α was immersed in a 15.0-mass % aqueous PVA solution for a duration of 3 minutes to obtain a PVA-added electrode plate i 1 containing 1.50 mass % of PVA with respect to the amount of active material.
[0034] (4) Hydration and Pre-Charging Step
[0035] Subsequently, each of the thus obtained PVA-added electrode plates a 1 , b 1 , c 1 , d 1 , e 1 , f 1 , g 1 , h 1 , and i 1 was immersed into an aqueous potassium hydroxide solution (having a specific gravity of 1.23), was subjected to a predetermined pre-charging (charging for 30% with respect to the electrode plate capacity; charging for 18 minutes at 1 It (wherein, It is a value expressed by rated capacity (Ah)/1 h (time)) by using metallic nickel plate as the counter electrode, and was subjected to rinsing and drying. Thus were obtained cadmium negative electrodes a, b, c, d, e, f, g, h, and i.
2. Comparative Example
[0036] Separately, the heated electrode plate α, whose 99% of the active material (cadmium hydroxide) was changed into cadmium oxide, was immersed into an aqueous potassium hydroxide solution (having a specific gravity of 1.23), was subjected to a predetermined pre-charging (in a manner similar to the pre-charging described above) by using a metallic nickel plate as the counter electrode, and was subjected to rinsing and drying. Thus was obtained a chemically converted electrode plate x 1 having a predetermined pre-charge similar to above. Further, a chemically converted electrode plate y 1 having pre-charged to 110% of predetermined pre-charge was prepared.
[0037] Subsequently, the thus obtained chemically converted electrode plates x 1 and y 1 were each immersed in a 5.0-mass % aqueous PVA solution for a duration of 3 minutes to achieve a PVA addition of 0.20 mass % with respect to the amount of active material (in this case again, active material in a base reduced to cadmium hydroxide), and were dried to obtain cadmium negative electrodes x and y having polyvinyl alcohol added to the surface and in the inside of the chemically converted electrode plates.
[0038] 3. Measurement of Discharge Capacity
[0039] Then, each of the cadmium negative electrodes a, b, c, d, e, f, g, h, i, x, and y was allowed to discharge in an aqueous potassium hydroxide solution (having a specific gravity of 1.23) at a current of 1.0 It until a voltage of 1.50 V was achieved with respect to metallic nickel plate used as the counter electrode. From the discharge time, the quantity of discharge (i.e., quantity of discharge reserve) by pre-charging was obtained for each of the cadmium negative electrodes a, b, c, d, e, f, g, h, i, x, and y. Then, from each of the discharge for the cadmium negative electrodes a, b, c, d, e, f, g, h, i, x, and y, the discharge capacity ratio (%) was calculated by taking the discharge quantity of the cadmium negative electrode x as 100. The results are given in Table 1 below.
TABLE 1 Type of CdO Added Discharge electrode generated PVA Timing of Pre- capacity ratio plate (%) (%) adding PVA charge (%) a 99 0.20 before fixed 112 hydration b 99 0.05 before fixed 107 hydration c 99 1.00 before fixed 109 hydration d 70 0.03 before fixed 106 hydration e 70 1.00 before fixed 107 hydration f 60 0.20 before fixed 103 hydration g 50 0.20 before fixed 96 hydration h 99 0.02 before fixed 100 hydration i 99 1.50 before fixed 97 hydration x 99 0.20 after fixed 100 hydration y 99 0.20 after 110% 109 hydration
[0040] From the results shown in Table 1 above, on comparing cadmium negative electrode x with the cadmium negative electrode a containing 99 mass % of cadmium oxide (CdO) converted by heat treatment and 0.20 mass % of added PVA, it can be clearly understood that the cadmium negative electrode a yields discharge capacity for pre-charging larger by about 12% as compared with that of the cadmium negative electrode x. Further comparing the cadmium negative electrode a with the cadmium negative electrode y containing the generated cadmium oxide (CdO) and the added PVA at same quantities but increased in pre-charging by 10%, it can be understood that the cadmium negative electrode a yields discharge capacity for pre-charging larger by about 3% as compared with that of the cadmium negative electrode y.
[0041] In the case of cadmium negative electrode a, almost all of the active material (cadmium hydroxide) is converted into cadmium oxide at the heat treatment, and a proper amount of PVA is added to the electrode plate. Thus, the results indicate that, at pre-charging, the cadmium negative electrode a is converted into cadmium hydroxide having a large surface area (i.e., γ-type cadmium hydroxide) by the hydration which occurs on immersing the cadmium negative electrode a into an aqueous alkaline solution. Thus, presumably, the charge acceptability of the cadmium negative electrode a is increased at pre-charging as to exhibit superior discharge capacity for pre-charging as compared with the case of cadmium negative electrode y having its pre-charge capacity increased by 10%.
[0042] Further, on comparing the discharge capacity for pre-charging between the cases in which the amount of cadmium oxide (CdO) generated by heat treatment is set to the same amount of 99 mass %, and in which the amount of added PVA is changed, it can be understood that the discharge capacity for pre-charging decreases for too high or too low an amount of added PVA. More specifically, as compared with the case of cadmium negative electrode x, the discharge capacity is higher for all of cadmium negative electrode a containing 0.20 mass % of added PVA, cadmium negative electrode b containing 0.05 mass % of added PVA, and cadmium negative electrode c containing 1.00 mass % of added PVA.
[0043] On the other hand, the cadmium negative electrode h containing 0.02 mass % of added PVA and the cadmium negative electrode i containing 1.50 mass % of added PVA yield lower discharge capacities for pre-charging as compared with the case of cadmium negative electrode x. This is attributed to the fact that too small an addition of PVA results in a small ratio of converted cadmium oxide having large surface area (i.e., γ-type cadmium hydroxide), and in a less improvement on charge acceptability. On the other hand, an addition of PVA in excess inhibits the charge reaction.
[0044] The facts above indicate that there is an optimal range in the addition of PVA. Thus,the amount of added PVA (the “amount of added PVA” in this case signifies the amount added with respect to the total mass as reduced to cadmium hydroxide) is preferably more than 0.02 mass % and less than 1.50 mass %.
[0045] Further, on changing the conditions of heat treatment to vary the amount of generated cadmium oxide (CdO), it can be understood that the discharge capacity for pre-charging increases with increasing amount of generated cadmium oxide. More specifically, the discharge capacity for pre-charging decreases in the order of cadmium negative electrode a containing 99 mass % of cadmium oxide generated by heat treatment (the generated amount in this case signifies the quantity generated with respect to the total quantity of active material as reduced to cadmium hydroxide), cadmium negative electrodes d and e containing 70 mass % of generated cadmium oxide, cadmium negative electrode f containing 60 mass % of generated cadmium oxide, and cadmium negative electrode g containing 50 mass % of generated cadmium oxide.
[0046] The above fact is attributed to the decrease in ratio of cadmium oxide converted into active cadmium hydroxide (i.e., γ-type cadmium hydroxide) having a large surface area on hydration, thereby resulting in a decrease in charge acceptability at pre-charging. This therefore results in discharge capacity for pre-charging. From the results above, it can be understood that, in order to maintain the discharge capacity for pre-charging sufficiently high at a value well equivalent to that of cadmium negative electrode x or higher, the amount of generated cadmium oxide is preferably set to 60% or higher.
[0047] 4. Production of Sealed Type Nickel-Cadmium Storage Batteries
[0048] Each of the cadmium negative electrodes a, b, c, d, e, f, g, h, and i of the examples as well as the cadmium negative electrodes x and y of the comparative examples prepared above was cut into a predetermined size, and were each assembled into an electrode body by winding them together with a known sintered nickel positive electrode plate used as counter electrode, with an unwoven nylon cloth separator interposed between them.
[0049] Each of the electrode bodies thus obtained was inserted inside an outer can, and after injecting a 25 mass % aqueous potassium hydroxide solution (KOH) inside the outer can, the cans thus obtained were each sealed to obtain nickel-cadmium storage batteries (with a nominal capacity of 1300 mAh) A, B, C, D, E, F, G, H, I, X, and Y.
[0050] Thus were obtained nickel-cadmium storage battery A from cadmium negative electrode a, nickel-cadmium storage battery B from cadmium negative electrode b, nickel-cadmium storage battery C from cadmium negative electrode c, nickel-cadmium storage battery D from cadmium negative electrode d, and nickel-cadmium storage battery E from cadmium negative electrode e.
[0051] Furthermore, there were prepared nickel-cadmium storage battery F from cadmium negative electrode f, nickel-cadmium storage battery G from cadmium negative electrode g, nickel-cadmium storage battery H from cadmium negative electrode h, and nickel-cadmium storage battery I from cadmium negative electrode i.
[0052] Similarly, there were obtained nickel-cadmium storage battery X from cadmium negative electrode x and nickel-cadmium storage battery Y from cadmium negative electrode y.
[0053] 5. Measurement of Storage Capacity
[0054] Subsequently, each of the nickel-cadmium storage batteries A, B, C, D, E, F, G, and X was charged for 16 hours with a charge current of 0.1 It (160% charge), and after allowing to stand for 28 days at an ordinary temperature (about 25° C.) , they were each allowed to discharge at a discharge current of 1 It until the cell voltage (final voltage) became 1.0 V. Thus was obtained the discharge capacity (storage capacity) for each of the cells A, B, C, D, E, F, G, and X from the discharge time. Further, from the discharge after storage for each of the cells A, B, C, D, E, F, G, and X thus obtained, the ratio of discharge after storage (storage capacity ratio (%)) for each of the cells A, B, C, D, E, F, G, and X was calculated with respect to the nominal capacity taken as 100. The results are shown in Table 2 below.
TABLE 2 Type CdO Storage of generated Added Timing of Pre- capacity ratio cell (%) PVA (%) adding PVA charge (%) A 99 0.20 before fixed 76 hydration B 99 0.05 before fixed 75 hydration C 99 1.00 before fixed 75 hydration D 70 0.03 before fixed 73 hydration E 70 1.00 before fixed 72 hydration F 60 0.20 before fixed 66 hydration G 50 0.20 before fixed 51 hydration X 99 0.20 after hydration fixed 75
[0055] From the results shown in Table 2 above, it can be clearly understood that the storage characteristics of the cells decreases with decreasing amount of generated cadmium oxide (the generated amount in this case again signifies the quantity generated with respect to the total quantity of active material as reduced to cadmium hydroxide). This is presumably attributed to the fact that a decrease in the amount of generated cadmium oxide led to an insufficient decomposition of impurities such as nitrate groups adsorbed on filling the active material, and that it thereby resulted in low storage characteristics of the cell. Since storage characteristics well equivalent to or higher than that of cell X is obtained in case the generated amount of cadmium oxide is 70 mass % or higher, the amount of generated cadmium oxide is preferably set to 70 mass % or higher.
[0056] 6. Charge-Discharge Cycle Test
[0057] Then, each of the nickel-cadmium storage batteries A, D, E, H, I, X, and Y was subjected to a charge-discharge cycle test. Thus, each of the cells was charged at a charge current of 0.1 It for 16 hours (160% charge) at an ordinary temperature (ca. 25° C.), and after stopping charging for 1 hour, each of the cells was allowed to discharge at a discharge current of 1 It until the cell voltage (final voltage) reached 1.0 V. After performing the charge-discharge test, the ratio of discharge capacity at each cycle with respect to the capacity of the first cycle (i.e., the discharge capacity ratio with respect to the capacity of the first cycle (%)) was plotted in the ordinate while taking the number of cycle on the abscissa. Thus were obtained results shown in FIG. 1.
[0058] From the results shown in FIG. 1, it can be clearly understood that the cycle characteristics of the cell A (using the cadmium negative electrode containing 99 mass % of generated CdO and containing PVA added at an amount of 0.20 mass % before hydration; shown by open circles o in FIG. 1) is far improved as compared with that of cell X (using the cadmium negative electrode containing 99 mass % of generated CdO and containing PVA added at an amount of 0.20 mass % after hydration; shown by crosses + in FIG. 1). Furthermore, it can be understood that cell A yields cycle characteristics well comparable to, or even higher than, that of cell Y having a larger pre-charge (using the cadmium negative electrode containing 99 mass % of generated CdO, containing PVA added at an amount of 0.20 mass % after hydration, and subjected to pre-charging amounting to 110% of the fixed value; shown by reversed open triangles ∇ in FIG. 1). This is attributed to the improvement in the charge acceptability in pre-charging the negative electrode a that was used in cell A. Thus, a larger discharge reserve amount was achieved to improve the cycle characteristics.
[0059] Furthermore, although cell D (using a negative electrode containing 70 mass % of generated CdO and containing PVA added at an amount of 0.03 mass % before hydration; shown by reversed open squares □ in FIG. 1) and cell E (using a negative electrode containing 70 mass % of generated CdO and containing PVA added at an amount of 1.00 mass % before hydration; shown by reversed open rhombs ⋄ in FIG. 1) yield characteristics somewhat inferior to that of cell A, they still show improvements as compared with the case of cell X.
[0060] The fact above can be explained as follows. In cell D, the amount of generated CdO in cadmium negative electrode d was 70 mass %, which was smaller than that of cadmium negative electrode a, and the amount of added PVA was 0.03 mass %, which was also smaller than that of cadmium negative electrode a; thus, the amount of cadmium hydroxide having a larger surface area, which generated on hydration, decreased, and the charge acceptability on pre-charging resulted somewhat lower than the case of cadmium negative electrode a. These thereby led to yield a lower discharge reserve.
[0061] In cell E, the amount of generated CdO in cadmium negative electrode e was 70 mass %, and this was smaller than that of cadmium negative electrode a; thus, the amount of cadmium hydroxide having a larger surface area, which generated on hydration, decreased. However, the amount of added PVA was 1.00 mass %; this was larger than that of cadmium negative electrode a, and it led to the formation of a thicker PVA film to result in a somewhat impaired charge acceptability on pre-charging. Thus, it thereby resulted in a lower discharge reserve.
[0062] On the other hand, it can be understood that cell H (using a negative electrode containing 99 mass % of generated CdO and containing PVA added at an amount of 0.02 mass % before hydration; shown by crosses x in FIG. 1) and cell I (using a negative electrode containing 99 mass % of generated CdO and containing PVA added at an amount of 1.50 mass % before hydration; shown by open triangles Δ in FIG. 1) yield charge-discharge characteristics well comparable to those of cell X. The fact above can be explained as follows. In cell H, the amount of PVA added to CdO in cadmium negative electrode h was 0.02 mass %, which was far smaller than that of cadmium negative electrode a. Thus, the amount of cadmium hydroxide having a larger surface area, which generated on hydration, decreased, and the charge acceptability on pre-charging resulted lower than the case using cadmium negative electrode a. It thereby led to yield a discharge reserve nearly equal to that of cadmium negative electrode x.
[0063] In cell I, the amount of added PVA was 1.50 mass %; this was far larger than that of cadmium negative electrode a, and it led to the formation of a thicker PVA film to result in an inferior charge acceptability on pre-charging as compared to the case using negative electrode a. It thereby led to yield a discharge reserve nearly equal to that of cadmium negative electrode x.
[0064] From the facts above, it can be understood that the amount of generated cadmium oxide is preferably controlled to 70 mass % or higher, and that the amount of PVA to be added before hydration is controlled to a range of 0.03 mass % or higher and 1.10 mass % or lower.
[0065] 7. Study on the Polymerization Degree of PVA
[0066] In each of the examples above, description was given on cases using polyvinyl alcohol having a polymerization degree of 500 (PVA: POVAL (trademark) of grade 105, manufactured by Kuraray Co., Ltd.). Thus, the influence of the polymerization degree of the PVA on the discharge capacity after pre-charging was studied. Firstly, a heated electrode plate α subjected to the heat treatment described hereinbefore was immersed in an aqueous solution containing 5.0 mass % of PVA having a polymerization degree of 2000 (POVAL (trademark) of grade 120, manufactured by Kuraray Co., Ltd.) for 3 minutes to obtain a heated electrode plate containing PVA added at 0.20 mass % with respect to the mass of active material, and was dried to obtain a PVA-added electrode plate. The PVA-added electrode plate thus prepared was subjected to pre-charging (to achieve 30% charge of the electrode plate capacity) in a manner similar to that described above, and was further subjected to rinsing and drying. Thus was obtained cadmium negative electrode j.
[0067] Furthermore, a heated electrode plate α subjected to the heat treatment described hereinbefore was immersed in an aqueous solution containing 5.0 mass % of PVA having a polymerization degree of 2400 (POVAL (trademark) of grade 124, manufactured by Kuraray Co., Ltd.) for 3 minutes to obtain a heated electrode plate containing PVA added at 0.20 mass % with respect to the mass of active material, and was dried to obtain a PVA-added electrode plate. The PVA-added electrode plate thus prepared was subjected to pre-charging (to achieve 30% charge of the electrode plate capacity) in a manner similar to that described above, and was further subjected to rinsing and drying. Thus was obtained cadmium negative electrode k.
[0068] The cadmium negative electrodes j and k were allowed to discharge in a manner similar to above, and the discharge capacity for pre-charging was obtained from the discharge time for each of the cadmium negative electrodes j and k. Then, the discharge capacity ratio (%) for each of the cadmium negative electrodes a, j and k was calculated by taking the discharge quantity of the cadmium negative electrode x as 100. The results are given in Table 3 below.
TABLE 3 Amount of Type of electrode CdO generated Polymerization degree added PVA Timing of Pre- Discharge capacity plate (%) of PVA (%) adding PVA charge ratio (%) a 99 500 0.20 before fixed 112 hydration j 99 2000 0.20 before fixed 105 hydration k 99 2400 0.20 before fixed 98 hydration x 99 500 0.20 after hydration fixed 100
[0069] From the results shown in Table 3, it can be understood that cadmium negative electrode k containing PVA with polymerization degree of 2400 yields a smaller discharge capacity as compared with that of the comparative example, i.e., cadmium negative electrode x. On the other hand, cadmium negative electrode j having PVA with polymerization degree of 2000 added thereto yields a discharge capacity larger than that of the cadmium negative electrode x, but that it yields a discharge capacity smaller than cadmium negative electrode a containing PVA with polymerization degree of 500. This is presumably ascribed to the fact that a PVA with higher polymerization degree leads to the formation of a stubborn PVA film on the surface of the cadmium negative electrode, and that the film thus formed functions as to inhibit the charge-discharge reaction by preventing the contact between the electrolyte and the active material. Conclusively, it can be understood that it is preferred to use PVA having a polymerization degree of 2000 or lower in adding PVA before the hydration of cadmium negative electrode.
[0070] As described above, the invention comprises adding polyvinyl alcohol (PVA) to the heat treated electrode plate before hydrating cadmium negative electrode. Thus, polyvinyl alcohol functions to the active material (cadmium hydroxide) on hydration to allow the formation of γ-type cadmium hydroxide having an acicular crystal structure and a large surface area. Thus, the charge acceptability is improved to enable lowering of charge in pre-charging, and thereby enables a cadmium negative electrode having excellent cycle characteristics.
[0071] In the embodiments above, description has been given for an example performing hydration treatment on pre-charging; i.e., the method comprises immersing a heat treated electrode plate subjected to a heat treatment for removing nitrate groups, and performing pre-charging to effect the hydration treatment at the same time. However, the invention is not only limited to the case above, and similar effects can be achieved in case hydration treatment is performed after the heat treatment and prior to pre-charging.
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An object of the invention is to provide a method for producing a cadmium negative electrode having excellent cycle characteristics without impairing the production efficiency even in case the impurities incorporated during filling the active material should be removed by heat treatment. A method for producing sintered cadmium negative electrode according to the invention comprises: an active material filling step comprising filling the nickel sintered substrate with an active material based on cadmium hydroxide to obtain an active material filled electrode plate; a heating step comprising heating the active material filled electrode plate to change at least a part of the thus filled active material based on cadmium hydroxide into cadmium oxide; a polyvinyl alcohol adding step comprising adding polyvinyl alcohol into the active material filled electrode plate through the heating step; and a hydration step comprising hydrating the active material filled electrode plate added with polyvinyl alcohol (i.e., a step comprising immersing the electrode plate in an alkaline solution to convert cadmium oxide into cadmium hydroxide).
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] Priority is claimed to U.S. provisional application No. 60/172,688, filed Dec. 20, 1999, which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The field of the present invention relates to marketing products by providing information to a target audience and ensuring that the product information has been read and, optionally, learned. In particular, some embodiments of the present invention relate to providing product information to a participant, administering a quiz to determine whether the information has been satisfactorily learned by the participant, and providing a reward to the participant for learning the information. Other embodiments of the present invention relate to providing product information to a participant, administering a questionnaire to the participant, and providing a reward to the participant for answering the questionnaire.
[0003] While the present invention may be used to market to any type of product, it is particularly useful when the sale, dispensation, or recommendation of a particular product requires professional expertise or detailed knowledge about the product. The prescribing of pharmaceuticals or medical devices by doctors is an example of such a situation, and the preferred embodiments are described herein in that context. Of course, the invention may be applied in other contexts as well.
BACKGROUND OF THE INVENTION
[0004] It has been estimated that pharmaceutical companies spend over 8 billion dollars a year marketing drugs through various vehicles. Traditionally, efforts to market pharmaceuticals have been aimed either directly at potential end users of the drugs or at doctors who prescribe drugs. Of these two approaches, vastly more resources are spent on marketing aimed at doctors.
[0005] The process of getting a person to learn written information can be divided into three phases: disseminating the information to the person, getting the person to read the written information, and getting the person to understanding the information that was read.
[0006] One traditional way that pharmaceutical companies market their products to doctors is by running advertisements in selected media that doctors are likely to read, such as medical journals. Advertisements of this type may be targeted to doctors that practice in particular specialties by placing ads in appropriate journals. Another traditional way to market products to doctors is to obtain a mailing list of doctors that practice in a desired specialty, and to mail product information to those doctors. While both of these approaches can be successful in getting the product information into the hands of the doctor, these approaches do not address the final two phases of getting the doctor to read and understand the information.
[0007] Another traditional way that pharmaceutical companies market their products to doctors is through sales representatives who are hired to disseminate information about the companies' products. Using sales representatives has traditionally been an excellent way to get product information into the hands of the relevant doctors, because sales representative can tailor their presentation to the individual doctor being visited. Sales representatives can also establish a personal relationship with the doctors that they visit, and explain the benefits of their clients' products to the doctors in person. But due to the complex nature of many pharmaceuticals and medical devices, and the short amount of time that most doctors usually spend with sales representatives, sales representative usually supplement their visits with written information about the products. As a result, marketing pharmaceuticals using sales representatives can suffer from the same problems as placing ads in medical journals, because the final two phases of getting the doctor to read and understand the information are not addressed.
[0008] Moreover, even when conventional marketing approaches succeed in getting a doctor to read information that has been provided, these approaches do not address the final phase of understanding (or absorption). This phase is particularly important in the pharmaceutical field for a number of reasons. First, lack of absorption can result in lost opportunities for the treatment of certain conditions with certain drugs, which deprives the benefits of the drugs from the patients, and also deprives the benefits of making a sale from the pharmaceutical companies. Second, and more importantly, an incorrect understanding of certain product information could result in the improper prescribing of a drug, which might cause harm to a patient (e.g., when a certain drug interacts negatively with another drug, or when a certain drug is only appropriate for certain types of patients). Third, a more complete understanding of product information enables doctors to better evaluate potential risks and dangers to patients.
[0009] In short, with traditional marketing methods, it can be difficult to determine when product information provided to doctors has been read and when it has been absorbed. As a result, patients may miss out on the products' benefits, and large portion of the expended marketing resources may be wasted.
SUMMARY OF THE INVENTION
[0010] An object of the present invention is to ensure that information provided to participants is actually read. In certain embodiments of the present invention, another object is to ensure that the information is learned (or absorbed).
[0011] These objects are accomplished by providing information to the participant and subsequently administering either a quiz or a questionnaire about the provided information. When a quiz is administered, the participant will receive a reward if the participant's performance on the quiz is adequate, which ensures that the provided information has actually been absorbed. When a questionnaire is administered, the participant receives a reward for answering all of the questions, regardless of whether the answers are correct. This improves the chances that the information will be read and absorbed.
[0012] The present invention is particularly suited to situations where proper use of the product involves professional expertise or detailed knowledge about the product, such as drugs or medical devices that are prescribed by doctors.
[0013] In one preferred embodiment, a coupon or certificate is used to invite a participant to log on to an Internet web site. A remote Internet server provides product information to the participant, followed by a quiz or questionnaire about the provided information. When a quiz is administered, after the participant answers the quiz and submits the answers to the remote Internet server, the server grades the quiz to determine whether the participant has learned the information. If a sufficiently high grade has been achieved, the participant is rewarded by, for example, providing a credit at an on-line shopping web site. When a questionnaire is administered, the server provides the reward if all the questions have been answered, regardless of whether they have been answered correctly.
[0014] One aspect of the invention relates to a method of promoting a product or service. In this method, a user is invited to visit a web site, and material that promotes the product or service is presented to the user when the user visits the web site. Questions that relate to the presented material are presented to the user. Responses to the presented questions are accepted from the user, and a determination of whether a sufficient number of the responses are correct is made. If a sufficient number of the responses are correct, a reward is provided to the user.
[0015] Another aspect of the invention relates to a method of promoting a product or service. In this method, material that promotes the product or service is presented to the user when the user visits a web site, and a question that relates to the presented material is presented to the user. A response to the presented question is accepted from the user, and the accepted response is checked for correctness. If the response is correct, a reward is provided to the user.
[0016] Another aspect of the invention relates to a method of promoting a product or service. In this method, a user is invited to visit a web site, and material that promotes the product or service is presented to the user when the user visits the web site. Questions that relate to the presented material are presented to the user. Responses to the presented questions are accepted from the user, and the system determines whether a response to each of the questions has been accepted. When an accepted response is incorrect, the user is notified. If a response to each of the questions has been accepted, a reward is provided to the user.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] [0017]FIG. 1 is a sketch of a coupon that can be used in connection with a first embodiment.
[0018] [0018]FIG. 2 is a schematic illustration of a suitable computer setup used with the first embodiment.
[0019] [0019]FIG. 3 is a flowchart that depicts processes performed in the first embodiment.
[0020] [0020]FIG. 4 is an illustration of an initial instruction screen on a web site in the first embodiment.
[0021] [0021]FIG. 5 is an example of a coupon redemption screen of the first embodiment.
[0022] [0022]FIG. 6 is an example of a product information screen of the first embodiment.
[0023] [0023]FIG. 7 is an example of a quiz used in the first embodiment.
[0024] [0024]FIG. 8A is an example of a screen displayed after successful completion of a quiz in the first embodiment.
[0025] [0025]FIG. 8B is an example of a screen displayed after an unsuccessful completion of the quiz in the first embodiment.
[0026] [0026]FIG. 9 is a flowchart that depicts processes performed in a second embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] [0027]FIG. 1 is an example of a suitable coupon 20 for use with a first embodiment of the present invention. In this embodiment, the coupon 20 is first distributed and subsequently redeemed.
[0028] The coupon 20 illustrated in FIG. 1 may be printed on any suitable material such as paper or plastic, and includes a first field 21 that describes a reward that will be obtained when the coupon is ultimately redeemed. Examples of suitable rewards include a credit at a medical bookstore web site (e.g., $100, which is permitted under the AMA code of ethics as a complementary medical honorarium), or a particular medical book or supply selected by the coupon's sponsor (e.g., a stethoscope). It also includes a second field 22 with instructions on how to redeem the coupon 20 . Preferably, these instructions 22 provide an Internet address (i.e., a URL) which can be visited by the doctor to redeem the coupon. In embodiments where coupons are distributed electronically, (e.g., via email or via the Internet) this URL may be accessed by clicking on a suitable hypertext link.
[0029] The illustrated coupon 20 also includes a sponsor code 23 . Preferably, the sponsor code 23 is encoded to identify the sponsor (i.e., the company that issued the coupon), and the particular product being promoted by the coupon. Optionally, information that identifies a geographical region and/or the particular sales representative who distributed the coupon may also be encoded in the sponsor code 23 . This information in the sponsor code 23 may be encoded in a single field 23 as illustrated, which can be used as an index into a database that identifies the sponsor, product, region, and sales rep corresponding to each sponsor code. Alternatively, the sponsor code may be divided into a plurality of individual sub-fields (with, e.g., individual sub-fields to identify the sponsor, product, region, and sales rep), and the entry in each subfield may be used as an index into a suitable database that is indexed by subfields. As yet another alternative, instead of providing a number of sub-fields within a single contiguous sponsor code field, the sub-fields may be printed on the coupon 20 in a plurality of non-contiguous individual fields (not shown).
[0030] Additional information may also be encoded in the sponsor code, in accordance with the requirements of the particular marketing plan being implemented using the coupon 20 . For example, if the database is suitably programmed, the sponsor code 23 may be used to determine that a given coupon was distributed during a particular day of a particular trade show. Such information could then be used to measure the effectiveness of the sales representatives that were working on that particular day. This additional information may be accessed using the same sponsor code 23 which is used to index into the database, or in a subfield of the sponsor code (not shown) that is used to index into a supplemental database.
[0031] Preferably, each coupon 20 also includes a coupon number 24 , which functions as the serial number for the coupon. In an alternative preferred embodiment, the coupon number and the sponsor code may be combined into a single field, and the relevant information can be extracted therefrom using a suitable lookup table, where the value of the combined field is used as an index into the lookup table.
[0032] Initially, an appropriate coupon is distributed to a targeted doctor. Coupon distribution may be accomplished by having sales representatives hand the coupons to doctors in person at the doctors' offices. Alternatively, the coupons may be handed out at trade shows or conferences, placed in advertisements in medical journals, distributed by ordinary mail or e-mail, or distributed in any other suitable manner. Coupons may also be distributed electronically on appropriate Internet web sites.
[0033] Preferably, when coupons are distributed by sales representatives, the coupons are encoded (e.g., in the sponsor code, as described above, or in the coupon number) with information that can be used to identify the particular sales representative that distributed the coupon. This can be accomplished, for example, by printing out a stack of coupons with a common sales representative ID number, and keeping track of the particular sales representative to whom the stack was provided. Optionally, the sales representative may be asked to associate his or her name with a particular sales representative ID number by visiting a web page set up for this purpose.
[0034] [0034]FIG. 2 is an example of a data communication setup that can be used to redeem coupons that have been previously distributed. The illustrated setup is preferably implemented using a conventional computer 81 (e.g., an IBM™ PC compatible or an Apple™ iMac) running a suitable browser (e.g., Netscape™ Navigator). A connection with the Internet may be established using any of a variety of techniques well known to those skilled in the art, including, for example, using modems 82 , 83 to communicate with an Internet Service Provider (ISP) 84 , which communicates with the web server 86 via the Internet 85 . Optionally, particularly when the coupons are provided at a tradeshow, a dedicated computer that is accessible to the visiting public may be provided for the purpose of coupon redemption.
[0035] When a doctor wishes to redeem a coupon of the type illustrated in FIG. 1, the doctor follows the instructions 22 printed on the coupon 20 and visits the coupon redemption web site (whose URL is preferably printed on the coupon 20 ).
[0036] [0036]FIG. 3 is a flowchart of the processes implemented at the web server 86 once a doctor logs on to the appropriate web site by, for example, accessing the URL printed on the coupon 20 . Optionally, the URL on the coupon may direct the doctor to a web page that is dedicated to a single drug (e.g., www.medsite.com/drugname), dedicated to a single drug company (e.g., www.medsite.com/sponsorname), dedicated to coupon redemption only (e.g., www.coupon.medsite.com), or a non-dedicated web page (e.g., www.medsite.com).
[0037] The URL on the coupon may be used to direct the doctor to an initial instruction screen 30 , which may be co-sponsored by a drug company and the web site operator. FIG. 4 is an example of a suitable initial instruction screen 30 . Sending the doctor to an initial instruction screen 30 can provide sponsor companies with additional marketing opportunities before the coupon is actually redeemed. These additional marketing opportunities may be implemented by providing any desired type of information to the doctor using, for example, the regions 32 and 33 . The initial instruction screen 30 , as well as the other display screens described herein, are preferably created by the web browser running on the doctor's computer 81 based on an html (hypertext markup language) message provided by the web server 86 . The web server 86 may be programmed in any suitable way so as to produce the desired html message.
[0038] The initial instruction screen 30 also contains a region 31 that is used to implement step S 22 , where the coupon redemption process is initiated. In the illustrated example, when the doctor clicks on a button 31 B within the region 31 , the doctor's web browser will be directed to a coupon redemption screen 40 (shown in FIG. 5). In those embodiments where the URL on the coupon sends the doctor directly to a dedicated web page, step S 22 is skipped, and the doctor will arrive directly at the coupon redemption screen 40 (without requiring a click on the initial instruction screen 30 ). Optionally, the sponsor code may even be incorporated into the URL, so that the doctor can be sent directly to a redemption page custom-designed for a specific coupon.
[0039] Returning now to FIG. 3, steps S 24 , S 25 , and S 26 implement the processing associated with FIG. 5, which is an example of a suitable coupon redemption screen 40 . Preferably, the coupon redemption screen 40 includes instructions 41 requesting that the doctor enter the sponsor code and the coupon number in fields 42 , 43 provided for this purpose. While the FIG. 5 embodiment includes fields for the sponsor code 42 and the coupon number 43 , alternative field arrangements would be used when alternative field arrangements are used on the coupon itself (as described above).
[0040] The coupon redemption screen 40 also includes instructions 44 asking the doctor to type in his or her log-in ID number in a field 45 provided for this purpose. Preferably, the log-in ID is used as an index into a database that stores the area of practice for each doctor. Optionally, a history of visits to the coupon redemption site for each doctor may be indexed using the log-in ID. As yet another option, a password (not shown) that is associated with the log-in ID may also be requested at this point.
[0041] If the doctor does not have a log-in ID number, the doctor is invited to click on a button 46 to obtain a log-in ID. When the doctor clicks on the button 46 to request a log-in ID, the result of the test performed in step S 24 will be YES, and processing will proceed to step S 25 where a log-in ID is issued to the doctor. Preferably, in order to obtain a log-in ID, the doctor will have to provide his or her name, address, telephone number, and a list of areas of practice. Alternatively, when a suitable database of doctors is available, some of this information may be obtained from that database. In alternative preferred embodiments, log-in information is not obtained in advance. Instead, the doctor's name and address are requested at the end of the quiz-taking process.
[0042] Instructions 47 prompt the doctor to click on a button 48 after the sponsor code 42 , coupon number 43 , and the log-in ID number 45 have been entered (thereby implementing step S 26 ). When the doctor clicks on the continue button 48 , processing will proceed to step S 28 .
[0043] In step S 28 , the web server 86 decides which information to send to the doctor. This may be accomplished using the sponsor code 42 that was entered by the doctor on the coupon redemption screen 40 , which enables a particular coupon to be used to market a particular product. Alternatively, the determination of which information to send may be based on the specialty of the doctor, which can preferably be determined by indexing into a database using the log-in ID number 45 . As yet another alternative, when sufficiently detailed URLs are provided on the coupon, the determination of which information to send may be based on the URL being visited.
[0044] As yet another alternative, the determination of which information to send may be based on both the sponsor code 42 and the log-in ID number 45 . For example, if a particular drug company makes one drug for treating osteoporosis and a second drug for treating juvenile diabetes, both of these drugs may be marketed using a single coupon with the same sponsor code. When a doctor enters that particular sponsor code, the web server 86 would determine which information to send to that doctor based on the log-in ID number 45 . For example, when the doctor associated with the entered log-in ID number is a pediatrician, information about the juvenile diabetes drug would be sent, and when the doctor associated with a log-in ID is a geriatrics specialist, information about an osteoporosis drug would be sent.
[0045] Next, in step S 30 , information about the product is sent to the doctor. FIG. 6 shows an example screen 50 of such information. Preferably, this screen includes instructions 51 asking the doctor to read the information, and information content 52 , which may optionally include pictorial and/or graphic information. The information screen 50 preferably includes instructions 53 asking the doctor to click on a button 54 after the doctor has read the information 52 . Optionally, scroll bars may be provided (on this and other screens) if the information is too big to fit on the computer's 81 display screen. After the doctor has indicated that he or she has read the information, a quiz is provided to the doctor in step S 32 . In alternative embodiments, the product information 52 may be provided to the doctor off-line by, for example, mailing the information to the doctor or printing the information on the coupon 20 itself.
[0046] [0046]FIG. 7 is an example of a suitable quiz 60 . Preferably, the quiz 60 includes instructions 61 requesting that the doctor answer the questions 62 . Each question has an answer field 64 . After reading each question 62 , the doctor fills in the answer in the corresponding answer field 64 . The questions 62 may be multiple choice questions, with multiple choice answers 63 provided beneath the question. Alternatively, any other form of questions may be used (e.g., true/false or short answer questions). Instructions 65 prompt the doctor to click on the button 66 to submit the answers to the quiz. In alternative embodiments, the quiz 52 may be provided to the doctor off-line by, for example, mailing the quiz to the doctor or printing the quiz questions 62 on the coupon 20 itself.
[0047] Returning now to FIG. 3, after the answers have been submitted by the doctor, processing proceeds to step S 34 where a test is performed to determine whether the doctor has passed the quiz. This test may be accomplished, for example, by checking the answers provided by the doctor against a template of correct answers. When short answer questions are used, each question may have more than one correct answer, and each of these correct answers may be included in the template. When long answer questions are used, the correctness of each answer may be analyzed by a human operator or by a suitable artificial intelligence program. The passing grade for the quiz may be constant (e.g., always 80%) or may be specified by the sponsor company for each individual drug.
[0048] If the doctor passes the quiz, processing continues at step S 36 where a reward is provided to the doctor. When the reward is a credit at an online provider (e.g., medsite.com), the doctor is then invited, in step S 38 , to use the credit. FIG. 8A is an example of a suitable display 70 that may be used to invite the doctor to use the credit. Preferably, this display includes a message 71 informing the doctor that the questions have been answered correctly and that the doctor has earned a credit. It also includes button 72 that will send the browser to a web site or page that is preferably configured to accept the credit issued in step S 36 . Optionally, additional buttons (not shown) may be provided to direct the doctor to other participating web sites. When other types of rewards are provided (e.g., a specific item selected by the coupon's sponsor), suitable changes to the reward delivery process should be made, such as asking the doctor to specify a shipping address.
[0049] If the test in step S 34 indicates that the doctor did not pass the quiz, processing proceeds to step S 35 where the doctor is asked to correct the answers on the quiz. FIG. 8B shows a suitable display 75 used for this purpose. Preferably, it includes a message 76 informing the doctor that the quiz was not passed, and provides a button 77 for returning to the quiz. If the doctor uses this button 77 to return to the quiz, the doctor will be given a chance to correct all of the incorrect answers on the quiz. Optionally, either the entire quiz or only the incorrectly answered questions may be presented to the doctor in this step S 35 . Once the doctor has corrected the quiz, processing returns to step S 34 where the corrected quiz answers are checked.
[0050] In a variation of the first embodiment described above, the quiz questions are provided to the doctor one at a time, and an answer to each question is accepted after that question is presented (instead of providing the questions and accepting the answers in batches). In this variation, an opportunity to fix incorrect answers may be provided instantly, which can make the quiz-taking process more pleasant to the participant.
[0051] In another variation of the first embodiment, the quiz is replaced by a questionnaire, and the test to determine whether the participant passed (in step S 34 ) is replaced with a test to determine whether the participant has answered all of the questions (regardless of the correctness of the answers). The questionnaire may be administered in a single batch or one question at a time. Preferably, whenever a question is answered incorrectly, the correct answer is provided to the participant for educational purposes. This feedback should help the doctor to better understand the information being presented.
[0052] Optionally, instead of or in addition to asking questions about the information that has been previously provided, questions may be administered to provide sponsor companies with information about doctors' insights and attitudes towards selected drugs or other clinically relevant topics. A sponsor company may then choose to follow up with selected doctors based on their answers to these questions.
[0053] [0053]FIG. 9 is a flowchart of the processes implemented in an alternative embodiment that does not rely on a printed coupon. Instead, the FIG. 9 embodiment contemplates that the doctor will contact the web server 86 (shown in FIG. 2) on his or her own accord, or be invited to the web server by, for example, an Internet banner advertisement placed on appropriate web pages. Processing in this embodiment begins at step S 112 , where the system obtains information about the visiting doctor. A log-in ID number similar to the log-in ID of the first embodiment may be requested, which can be used to determine the doctor's area of practice. Alternatively, the doctor may provide information such as name, address, and areas of practice as described above in connection with step S 25 of the first embodiment. In other alternative embodiments, this information may be obtained at the end of the quiz-taking process.
[0054] In step S 114 , the doctor is categorized based on the information provided in step S 112 and optionally, qualified to determine if the web server 86 wishes to offer an electronic coupon to the doctor. This qualification may be based, for example, on the particular area of practice of the doctor, or on a database containing information indicating that a particular sponsor company would like to inform this particular doctor about a certain drug.
[0055] Next, in step S 116 , the system determines which information to send to the doctor. Preferably, this is accomplished using the area-of-practice information obtained in steps S 112 and S 114 . Optionally, a record of past transactions for each doctor may be maintained in the database, so that a new presentation may be made each time a particular doctor visits the coupon redemption web site, and to prevent duplicate coupon redemptions for reading the same information. In step S 118 , the doctor is invited to take a quiz in exchange for a credit. In step S 120 , a test is performed to determine whether the doctor has agreed to take the quiz. If the doctor has not agreed to take the quiz, processing ends. If the doctor has agreed to take the quiz, processing continues at step S 130 . The remaining steps S 130 -S 138 of the FIG. 9 embodiment correspond, respectively, to steps S 30 -S 38 of the first embodiment, described above. The variations to the first embodiment (e.g., providing quiz questions one at a time, and providing a questionnaire instead of a quiz) may be applied to this embodiment as well.
[0056] While the embodiments described above contemplate a particular user interface that provides information to the doctor by displaying text and pictorial or graphic images, and receives information from the doctor via entries that are typed into input fields and via mouse clicks, alternative user interfaces features may be substituted therefor. Examples of suitable alternative user interface features include the selection of numeric entries from pop-down menus; using hyperlinks to either supplement or replace the button clicks that are used to proceed to other screens; and using voice input and/or output. The implementation of these and numerous other alternative user interface approaches will be apparent to persons skilled in the relevant arts.
[0057] In the embodiments described above, a single web site is used as a starting point to market multiple products from one or more pharmaceutical companies. In alternative embodiments, individual web sites may be set up for each individual pharmaceutical company, or even for each individual drug.
[0058] Instead of redeeming the coupon 20 via a computer 81 connected to the Internet 85 , as described above, the coupon 20 may be redeemed in any number of alternative ways. For example, in one alternative embodiment, a coupon redemption system may be accessed by connecting to a private non-Internet network via modem. In another alternative embodiment, some of the functions that were implemented by the web server 86 in the above-described embodiments may be performed by the computer 81 instead of the web server (provided that the software running on the computer 81 is suitably modified). In another alternative embodiment, coupon redemption may be accomplished using an automated touch-tone or voice response system, implemented using any of a variety of techniques well known to those skilled in the art. In yet another alternative embodiment, coupon redemption may be accomplished using a live operator, by having the operator administer the quiz orally and log the doctor's responses. When any of these alternative coupon redemption methods are used, suitable modifications to the coupon itself and to the above-described coupon redemption process should be made, as will be apparent to those skilled in the art. For example, the coupon would include a telephone number for accessing a telephone-based coupon redemption system instead of a URL.
[0059] Of course, while the embodiments described above have been explained in the context of a pharmaceutical company marketing drugs to doctors, these embodiments may be applied to other fields and to other types of participants. For example, medical devices may be marketed to doctors, computers to IT specialists, and test instruments to engineers. The embodiments described above may even be applied in fields where the information provided is less technical. For example, automobile manufacturers could use the embodiments described above to market their products, and plumbers could use them to market their services. Numerous other applications can be readily envisioned.
[0060] In addition to ensuring that the provided information is read (or absorbed) by the participants, data from the coupon redemption process of the above described embodiments may be collected and tracked in a marketing database. This database may subsequently be used, for example, to determine which types of products interest particular participants, to improve future marketing efforts, to track the success of a given coupon program, to track the success of a particular sales representative, and to generate reports for companies that sponsor the coupons.
[0061] Finally, while the present invention has been explained in the context of the preferred embodiments described above, it is to be understood that various changes may be made to those embodiments, and various equivalents may be substituted, without departing from the spirit or scope of the invention, as will be apparent to persons skilled in the relevant art.
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Information is provided to a participant, and a quiz or questionnaire about the provided information is subsequently administered. In the quiz embodiment, the participant receives a reward (such as a credit at an on-line shopping web site) if the performance on the quiz is adequate. Tying the reward to adequate performance on the quiz ensures that the information provided has been adequately learned. In the questionnaire embodiment, the participant receives a reward for answering all of the questions. Preferably, incorrect answers are corrected to promote learning of the information. In a preferred embodiment, a coupon is used to invite participation in the program, and the Internet is used to transmit the information, the quiz or questionnaire, and the answers.
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RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 13/205,158, filed Aug. 8, 2011 (now allowed), which is a continuation of U.S. application Ser. No. 11/019,012, filed Dec. 21, 2004 (issued as U.S. Pat. No. 8,014,411), which is a continuation of U.S. application Ser. No. 09/803,090 (issued as U.S. Pat. No. 6,847,641), filed Mar. 8, 2001, entitled “Apparatus and Methods for Establishing Virtual Private Networks in a Broadband Network,” which relates to U.S. application Ser. No. 09/737,916 (issued as U.S. Pat. No. 6,741,562), entitled “Apparatus and Methods for Managing Packets in a Broadband Data Stream,” filed on Dec. 15, 2000, and U.S. application Ser. No. 09/737,917 (issued as U.S. Pat. No. 6,987,732), entitled “Apparatus and Methods for Scheduling Packets in a Broadband Data Stream,” filed on Dec. 15, 2000, and U.S. application Ser. No. 09/661,244, entitled “Apparatus and Methods for Processing Packets in a Broadband Data Stream,” filed on Sep. 13, 2000. The above Applications are hereby incorporated by reference in their entireties.
BACKGROUND OF THE INVENTION
As the Internet evolves into a worldwide commercial data network for electronic commerce and managed public data services, increasingly, customer demands focus on the need for advanced Internet Protocol (IP) services to enhance content hosting, broadcast video and application outsourcing. To remain competitive, network operators and Internet service providers (ISPs) must resolve two main issues: meeting continually increasing backbone traffic demands and providing a suitable Quality of Service (QoS) for that traffic. Currently, many ISPs have implemented various virtual path techniques to meet the new challenges. Generally, the existing virtual path techniques require a collection of physical overlay networks and equipment. The most common existing virtual path techniques are: optical transport, asynchronous transfer mode (ATM)/frame relay (FR) switched layer, and narrowband Internet protocol virtual private networks (IP VPN). FIG. 1 schematically illustrates the common existing virtual path switched layers.
The optical transport technique 102 is the most widely used virtual path technique. Under this technique, an ISP uses point-to-point broadband bit pipes to custom design a point-to-point circuit or network per customer. Thus, this technique requires the ISP to create a new circuit or network whenever a new customer is added. Once a circuit or network for a customer is created, the available bandwidth for that circuit or network remains static. The ATM/FR switched layer technique 104 provides QoS and traffic engineering via point-to-point virtual circuits. Thus, this technique does not require the creation of dedicated physical circuits or networks, as is the case with the optical transport technique 102 . Although this technique 104 is an improvement over the optical transport technique 102 , this technique 104 has several drawbacks. One major drawback of the ATM/FR technique 104 is that this type of network is not scalable. In addition, the ATM/FR technique 104 also requires that a virtual circuit be established every time a request to send data is received from a customer.
The narrowband IP VPN technique 106 uses best effort delivery and encrypted tunnels to provide secured paths to the customers. One major drawback of a best effort delivery is the lack of guarantees that a packet will be delivered at all. Thus, this is not a good candidate when transmitting critical data.
SUMMARY OF THE INVENTION
According to an example embodiment, there is provided a method for establishing virtual private networks in a communication network. The method comprises creating a set of label switched path trunks, assigning a trunk label to each of the label switched path trunks, and configuring a set of logical service networks via multiprotocol labels to carry multiple virtual private network paths using the label switched path trunks. In an example embodiment, each of the label switched path trunks provides a class of services and a trunk label associated with each label switched path trunk identifies the class of services, provided by that trunk. In one embodiment, creating the set of label switched path trunks includes creating the set of label switched path trunks at each service location. A service provider may wish to provide services at multiple service locations. In an example embodiment, the logical service networks are configured statically via service provider input. In another example embodiment, the logical service networks are configured automatically via software.
According to another example embodiment, there is provided a method comprising stacking a trunk label on a multi-protocol label switching stack, assigning a unique identifier to a customer site, and stacking the unique identifier on the trunk label. In another embodiment, the method further comprises assigning a unique group identifier to customer sites for a customer and establishing at least one virtual path between the customer sites.
Further example embodiments of the present invention provide for a virtual private network with a set of label switched path trunks. A label switched path trunk is defined for a class of services. A trunk label identifies the class of services for the label switched path trunk. A set of logical service networks are configured via multiprotocol labels to carry multiple virtual private network paths via the label switched path trunks.
A set of label switched path trunks may be defined at each service location. The set of logical service networks may be configured statically or automatically. In one embodiment, a trunk label is stacked on a multiprotocol label switching stack. A unique identifier may be assigned to a customer site by stacking the unique identifier on the trunk label. A unique group identifier may be associated with customer sites for a designated customer. The virtual private network uses the unique group identifier to form at least one virtual path between the customer sites.
Example embodiments of the present invention allow service providers to reduce multiple overlay networks by creating multiple logical service networks (LSNs) on a physical or optical fiber network. The LSNs are established by the service provider and can be characterized by traffic type, bandwidth, delay, hop count, guaranteed information rates, and/or restoration priorities. Once established, the LSNs allow the service provider to deliver a variety of services to different customers depending on each customer's traffic specifications. For example, different traffic specifications are serviced on different LSNs depending on each LSN's characteristics. In addition, such LSNs, once built within a broadband network, can be customized and sold to multiple customers.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.
FIG. 1 schematically illustrates a prior art virtual path implementation.
FIG. 2 schematically illustrates an example virtual path implementation in accordance with an embodiment of the invention.
FIG. 3 schematically illustrates example LSNs in accordance with an embodiment of the invention.
FIG. 4 schematically illustrates an example VPN in accordance with an embodiment of the invention.
FIG. 5 schematically illustrates example virtual paths for a customer in accordance with an embodiment of the invention.
FIG. 6 schematically illustrates example virtual paths for multiple customers in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
A description of example embodiments of the invention follows.
Example embodiments of the present invention relate generally to apparatus and methods for establishing virtual private networks. In particular, embodiments of the present invention relate to apparatus and methods for establishing virtual private networks in a broadband network.
Thus, it is a goal of example embodiments of the present invention to provide apparatus and methods that reduce operating costs for service providers by collapsing multiple overlay networks into a multiservice IP backbone. In particular, it is a goal of example embodiments of the present invention to provide apparatus and methods that allow an ISP to build the network once and sell such network multiple times to multiple customers.
FIG. 2 schematically illustrates example virtual path switched layers 200 in accordance with an example embodiment of the invention. The virtual path switched layers 200 combine switching and routing to provide virtual services. In particular, the virtual path switched layers 200 combine the strengths of layer 106 (i.e., scalability and flexibility) and layer 202 (i.e., security and quality of service). In FIG. 2 , a multiprotocol label switching (MPLS) switched layer 202 replaces the ATM/FR switched layer 104 in FIG. 1 . Multiple label switched path trunks (LSP trunks) are set up as trunk groups in the optical transport layer 102 for transporting multiple virtual routing services (VRS) paths 206 . The LSP trunks allow service providers to engineer traffic. In an example embodiment, virtual routed networks 204 are located at the edge of the MPLS switched layer 202 . The VRS paths 206 are connected to virtual routed networks 204 via the MPLS switched layer 202 . In one example embodiment, VRS routed networks 204 are uniquely identified; thus, security is guaranteed. In an example embodiment, non-VRS traffic is routed to an Internet router via the IP routed Internet layer 106 . In an example embodiment, the virtual path switched layers 200 do not maintain Internet routing tables known in the art.
FIG. 3 schematically illustrates example LSNs in accordance with an example embodiment of the invention. A service provider creates LSP trunks at each location of service. For example, multiple LSP trunks are created in San Francisco, St. Lewis, Chicago, and New York City. In an example embodiment, an LSP trunk is established for each service class. Each LSP trunk may be implemented using the technology described in the commonly assigned co-pending patents and patent applications: U.S. application Ser. No. 09/737,916 (issued as U.S. Pat. No. 6,741,562), entitled “Apparatus and Methods for Managing Packets in a Broadband Data Stream,” filed on Dec. 15, 2000, and U.S. application Ser. No. 09/737,917 (issued as U.S. Pat. No. 6,987,732), entitled “Apparatus and Methods for Scheduling Packets in a Broadband Data Stream,” filed on Dec. 15, 2000, and U.S. application Ser. No. 09/661,244, entitled “Apparatus and Methods for Processing Packets in a Broadband Data Stream,” filed on Sep. 13, 2000; all of which are expressly incorporated by reference in their entireties.
In an example embodiment, each LSP trunk is identified by a trunk label. In one embodiment, such a trunk label also identifies the class of services assigned to the associated LSP trunk. In one embodiment, LSP trunk labels ( 302 , 304 , 306 , and 308 ) are pushed onto an MPLS stack. LSNs are established based on the created LSP trunks. In one embodiment, LSNs are established statically by service provider input. In another embodiment, LSNs are established automatically by software. After LSNs are established or built, customer and customer traffic can be customizably added to such networks.
FIG. 4 schematically illustrates an example VPN for a customer in accordance with an embodiment of the invention. In FIG. 4 , a customer A signs up for services at multiple locations (customer sites). In one embodiment, each customer site is assigned a unique identifier (e.g., a VPN label). In an example embodiment, such a unique identifier is stacked on top of the trunk label in the MPLS stack. For example, in FIG. 4 , customer A at location 1 is assigned a label 402 stacked on top of LSP trunk 302 , customer A at location 2 is assigned a label 404 stacked on top of LSP trunk 304 , and customer A at location 3 is assigned a label 406 stacked on top of LSP trunk 308 . In an example embodiment, customer sites for a customer are then grouped and assigned a unique VPN group label “A”. The unique VPN group label “A” associates customer sites of customer A in a private network.
FIG. 5 schematically illustrates example virtual paths for a customer in accordance with an embodiment of the invention. A private IP path is established to route traffic between customer sites. For example, a private IP path 502 is established between location 1 and location 2, a private IP path 504 is established between location 2 and location 3, and a private IP path 506 is established between location 1 and location 3. In an example embodiment, a private IP path is a logical path. The private IP paths 502 , 504 , and 506 are unique to customer A and such paths can be policed.
In one embodiment, private IP paths for each customer are associated to each other by a unique VPN group label. In an example embodiment, the established private IP paths for each customer and the associated unique VPN group label provide security guarantees. In addition, the LSP trunks ( 302 , 304 , and 308 ) at each customer site associate data to a known quality and/or a class of service.
FIG. 6 schematically illustrates multiple VPNs established for multiple customers in accordance with an embodiment of the invention. In FIG. 6 , customer B signs up for services at multiple locations (customer sites). A unique VPN label is assigned to each customer site (location) for customer B. As shown, customer B at location 1 is assigned a label 602 stacked on top of LSP trunk 302 , customer B at location 2 is assigned a label 604 stacked on top of LSP trunk 306 , and customer B at location 3 is assigned a label 606 stacked on top of LSP trunk 308 . In an example embodiment, customer sites for customer B are then grouped and assigned a unique VPN group label “B.” The unique VPN group label “B” associates customer sites for customer B in a private network. Next, a VPN for customer B is established. For example, a private IP path 608 is established between location 1 and location 2, a private IP path 610 is established between location 2 and location 3, and a private IP path 612 is established between location 1 and location 3. The private IP paths 608 , 610 , and 612 are unique to customer B and can be policed.
Generally, the separation of the service plane from the network provides significant scalability advantages, one major advantage being that the network does not need to know about the end services offered beyond providing the proper quality of service (QOS) transport. For example, a carrier can establish QOS parameters and design a network using a mesh of LSP trunks. The LSP trunks signaling is propagated and threaded from node-to-node using, for example, common signaling techniques like resource reservation protocol (RSVP) or constraint routing-label distribution protocol (CR-LDP). Network and trunk redundancy parameter(s) get established in advance. After the network is established, the carrier can add customers at the edge of the network. Edge services get signaled end-to-end regardless of whether the network or the LSP trunks are aware that such signaling is taking place. In a sense, the service creation only affects the end node where the service is actually being created. Thus, service creation is scalable because it is signaled from end-to-end. A failure in the network gets dealt with at a network level, for example, by restoring LSP trunks that are usually an order of magnitude lower than the number of services that run on those trunks.
Further example embodiments of the present invention may include a non-transitory computer readable medium embodiment containing instruction that may be executed by a processor that includes code for establishing virtual private networks in a communication network. The code is operable to create a plurality of label switched paths between corresponding locations of service that are optionally not directly linked. Each of the label switched paths that are created provides a class of services. The code is further operable to assign a label to each of the label switched paths. The assigned label identifies a class of services for the label switched paths. The code is still further operable to configure a set of logical service networks to carry multiple virtual private network paths using the label switched paths. The set is so configured via multiprotocol labels.
It should be understood that elements of the block and flow diagrams described herein may be implemented in software, hardware, firmware, or other similar implementation determined in the future. In addition, the elements of the block and flow diagrams described herein may be combined or divided in any manner in software, hardware, or firmware. If implemented in software, the software may be written in any language that can support the example embodiments disclosed herein. The software may be stored in any form of computer readable medium, such as random access memory (RAM), read only memory (ROM), compact disk read only memory (CD-ROM), and so forth. In operation, a general purpose or application specific processor loads and executes software in a manner well understood in the art. It should be understood further that the block and flow diagrams may include more or fewer elements, be arranged or oriented differently, or be represented differently. It should be understood that implementation may dictate the block, flow, and/or network diagrams and the number of block and flow diagrams illustrating the execution of embodiments of the invention.
The foregoing examples illustrate certain example embodiments of the invention from which other embodiments, variations, and modifications will be apparent to those skilled in the art. The invention should therefore not be limited to the particular embodiments discussed above, but rather is defined by the claims.
While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.
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Service providers can reduce multiple overlay networks by creating multiple logical service networks (LSNs) on the same physical or optical fiber network through use of an embodiment of the invention. The LSNs are established by the service provider and can be characterized by traffic type, bandwidth, delay, hop count, guaranteed information rates, and/or restoration priorities. Once established, the LSNs allow the service provider to deliver a variety of services to customers depending on a variety of factors, for example, a customer's traffic specifications. Different traffic specifications are serviced on different LSNs depending on each LSN's characteristics. Such LSNs, once built within a broadband network, can be customized and have its services sold to multiple customers.
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BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to an electrical isolation circuit and more particularly to an opto-coupler electrical isolation circuit.
2. Discussion of The Prior Art
An opto-coupler has found wide acceptance in many applications as a means of isolating electrical signals from each other. For example, peripheral equipment associated with computer systems are often subjected to large transient currents which flow into the ground loop or ground line and as a result cause the ground line to rise in voltage. Servo motors are often required to drive output devices such as tape decks and necessitate output voltages in the 150 V and upward range. The transient or surge currents often cause the ground line to rise by more than 5 or 6 volts which in turn causes a feedback from the output to input devices and back to the main frame of the computer, thus triggering erroneous circuit operation. An opto-coupler is an ideal structure for positively eliminating this feedback in an inexpensive and reliable manner.
Existing opto-couplers are extremely expensive and require complex amplifying circuits on one hand, or in the alternative operate at inadequate switching speeds and signal levels thus making them undesirable and impractical for many applications.
One prior art opto-coupler employs a radiation source, such as a light emitting diode, and a silicon diode detector. The diode detector is constituted by a monolithic structure comprising a substrate, an N epitaxial layer, and a surface diffused P-region for forming the PN junction. With the PN junction reversed biased, a minority carrier current is generated by the movement of electrons from the P-diffused region into the epitaxial layer and the movement of holes from the N epitaxial layer into the P-diffused region. The miniority carrier current primarily occurs by the generation of electron hole pairs in the N epitaxial region upon the incidence of radiation. This type of detector suffers from major drawbacks.
It is recognized that for integrated circuit application it is desirable to provide conventional active devices on the same chip or substrate with the detector. Accordingly, it is most advantageous that the detector device be capable of being fabricated by standard integrated processing techniques. Most advantageously these techniques dictate that the epitaxial thickness be in the order of five to ten microns. However, if the prior art detector is fabricated in a thin epitaxial layer much of the incident radiation passes through the two active regions constituting the PN junction, that is, the upper surface planer P-diffused region and the N epitaxial region without being completely absorbed. Consequently, the surface diode detector is incapable or is limited in the magnitude of current which is capable of generating from the incident radiation. For example, with a sixteen milliamp current being applied to a gallium arsenide LED radiation source and the conventional silicon diode detector located in the N epitaxial region, approximately 5 to 8 microamperes of current is generated, and this low level of generated current in turn gives rise to two attendant problems.
Firstly, the switching response time of the detector is inversely proportional to the generated current. By way of example, for 10 microamperes and a 10 micro-micro farad capacitor associated with the detector (a capacitor in parallel with a current source is the diode detector equivalent), it would take approximately 5 micro seconds to generate a 5 volt signal across the detector. This response time is unacceptable from many applications and accordingly would require additional integrating circuits to increase the response time, or would require high beta transistors or Darlington configurations with the obvious attendant disadvantages.
Secondly, the low magnitude of current generated by the detector would require a great number of sophisticated and costly amplifying stages in order to be capable of generating a sixteen milliampere output current from a 10 micro ampere detector current. As many as 15 or 20 transistors sometimes are required for this amplification function is some known prior art units.
An ostensible solution to this problem caused by incomplete absorption of the incident radiation within the active regions is to increase the epitaxial thickness. An epitaxial thickness of thirty microns has been suggested in order to insure substantially complete absorption by the active regions employed to generate the miniority carrier current in the device detector and thus increase the magnitude of the generated currents. An apparent additional solution is to increase the N epitaxial resistivity from 1 ohm cm. to 30 ohm cm. However, these alternatives create severe processing problems for optimized integrated circuit implementation.
The processing time to form junction isolation in a thick epitaxial region is extremely long and would cause extensive surface damage as well as being difficult to control. Other forms of isolation processes would also be extremely expensive, impractical, or difficult to achieve with extremely large epitaxial thicknesses, or diffused layers.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an improved, economical, and reliable opto-coupler unit.
Another object of the present invention is to provide an improved opto-coupler unit having a radiation detecting device capable of generating increased signal levels without sacrificing response speeds.
Another object of the present invention is to provide an improved opto-coupler unit having a detecting device which maximizes utilization of incident radiation.
A further object of the present invention is to provide an opto-coupler unit having a detecting device for producing desirable current levels while minimizing undesirable effects of parasitic capacitance.
A further object of the present invention is to provide an opto-coupler unit wherein the detecting device can be readily integrated in an inexpensive manner on a single chip for providing the radiation detection and amplification with a minimal number of components.
Another object of the present invention is to provide an opto-coupler unit having a detecting device which can be fabricated inexpensively, reliably, and with high yields in accordance with established high performance integrated circuit processing techniques.
Another object of the present invention is to provide an opto-coupler having a detecting device which when implemented in integrated circuit form possesses minimum undesirable capacitance, optimum compatability with thin epitaxial and diffused layer integrated circuit processing techniques, for example, 5 to 8 microns, and optimum compatibility with idealized epitaxial resistivity, for example 1 or 2 ohm cm. resistivity values.
Another object of the present invention is to provide an opto-coupler unit in which the detecting and amplifying function can be fabricated on a single semiconductor chip having significantly reduced overall dimensions then was previously obtainable.
Another object of the present invention is to provide an improved opto-coupler unit which can be economically and readily packaged with a minimum number of wiring or lead restraints.
Another object of the present invention is to provide an improved opto-coupler unit having a radiation detective device and amplifying circuitry having improved power dissipation characteristics.
A further object of the present invention is to provide an improved opto-coupler unit having a diode and amplifying section which requires a minimum number of components, but yet is still capable of generating a sufficiently high output voltage level compatible with transistor-transistor logic, TTL.
Another object of the present invention is to provide an improved opto-coupler circuit having a radiation detecting device which does not require extremely high beta transistors or Darlington circuits in order to provide fast response time and output voltage levels compatible with a TTL logic family.
A further object of the present invention is to provide an improved opto-coupler unit having a radiation detecting device capable of generating current over a much larger active integrated circuit area without increasing its silicon area over prior art integrated circuits, and in fact reducing the silicon area over that previously known.
In accordance with the aforementioned objects, the present invention provides an opto-coupler unit readily packaged into a single package having a radiation emitting device energized by an electrical input and a physically separated detecting device responsive to incident radiation for generating an output voltage electrically isolated from the electrical signal applied to the radiation source. The device includes an optimum semiconductor diode device constituted by first and second active regions disposed within a semiconductor body for absorbing a maximum amount of incident radiation so as to minimize incident radiation transmittal losses.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of cross section, partially broken away, of the radiation source and the improved detecting device of the present invention.
FIG. 2 is an electrical schematic diagram illustrating the incorporation of the improved radiation detecting device into an amplifying circuit for obtaining a high level output voltage with a minimum number of integrated circuit components.
FIG. 3 illustrates typical generated voltage and current waveforms of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now referring to FIG. 1, it illustrates one preferred embodiment device structure of the present invention.
In order to form the semiconductor detecting diode and attendant amplifying generated circuit on a single monolithic chip, a starting P-conductivity substrate 10 is employed. In the preferred embodiment, the substrate 10 possesses a resistivity of approximately 8 to 30 ohm cm. resistivity and a thickness of approximately 5 mils or 125 microns. An N-conductivity type layer 12 is deposited over the starting substrate 10. In the preferred embodiment, layer 12 is constituted by an epitaxially grown material having a 1 to 3 ohm cm. resistivity and a thickness of approximately 5 to 8 microns. In order to provide an electrical contact to the semiconductor detecting diode an N+ conductivity type region 14 is formed in the layer 12 and a P+ conductivity type isolation region 16 is employed in order to electrically isolate the diode. In the preferred embodiment, the isolated region 16 and N+ conductivity region 12 are formed by diffusion.
The light generating device which is positioned vertically above the light detecting device and separated therefrom is schematically illustrated as a gallium arsenide or gallium arsenide phosphide light emitting diode 18 (LED) comprising an N type substrate 20 having a P+ region 22 formed therein. Electrical exitation of the LED junction causes infrared radiation schematically depicted as 26 to be emitted from the LED source and impinge upon and be absorbed by the radiation diode detecting device.
The PN junction formed between the substrate 10 and the layer 12 forms a PN junction indicated at 30 is bounded by an active N and P regions located in the layer 12 and substrate 10, respectively. From an electrical standpoint, the detecting diode is schematically equivalent to a current source and parallel capacitor and is represented schematically by elements 32 and 34, respectively, extending across the pair of active N and P regions. The dotted line 35 represents the total area which is capable of generating electron-hole movement across the reverse biased PN junction 30 in order to cause electron-hole recombination and thus generate an output current in response to the incident radiation 26. It is significant that with the diode detector of the present invention, the total active area is in the range of 30 to 50 microns thick and thus the incident radiation 26 generated by the LED radiation source 18 is substantially completely absorbed by the N and P active regions and thus maximum current levels are generated.
In actual implementation the radiation source 18 and the detector and amplifying chip are first encapsulated in a clear plastic environment and then sealed with a suitable exterior opaque case.
Only portion of the amplifying circuit employed to amplify the generated current of the diode detector is depicted, as the remaining integrated circuitry is of a conventional nature and is not illustrated for purposes of clarity. The electrical current generated by the diode detector is first amplified by a trans-impedance amplifier constituted by a resistor device 40 formed by a P type region 42 located in the N type epitaxial layer 12 and located over an N+ buried layer 44. A bipolar transistor constituted by a buried N+ layer 46, a P-conductivity base region 48 and an N+ emitter region 50 is also formed in the monolithic integrated circuit chip and is isolated by a P+ region depicted at 17 18.
A passivating insulating layer of material, such as silicon dioxide, is illustrated at 52 and is deposited over the upper surface of the N type epitaxial layer 12. Appropriate contact holes are open in order to provide a metallized contact 54 to the N+ diffused contact region 14, a pair of metallized contacts 56 and 58 to the P type diffused resistor 40, and base contact, emitter contact, and collector contact depicted at 60, 62, and 64, respectively. The metallized interconnecton between the diode detector, the P diffused resistor 40, and the trans-impedance bipolar transistor generally designated as 66, 40 and 70 are interconnected by a metallized interconnection pattern deposited over the passivating layer 52, and for purposes of clarity is simply shown as interconnection lines 72 and 74.
Now referring to FIG. 2, it illustrates a complete schematic diagram of a monolithic integrated circuit containing the diode detector and amplifying circuitry, a portion of which was depicted in FIG. 1 in device form as detecting diode 66, resistor 40, and bipolar transistor 70.
With the improved detecting diode 66 of the present invention, minimal and uncomplicated amplifying circuitry is necessary. The circuit essentially comprises an input trans-impedance amplifier stage 82, an operational amplifier intermediate stage 83, and an output amplifier stage 84. The monolithic integrated circuit detecting and amplifying circuitry of the present invention not only requires minimal uncomplicated devices but also operates with minimal power requirements. The input trans-impedance stage converts the detected current of diode 66 into a voltage at node 72. The supply system for the present detecting and amplifying circuit is constituted by a supply voltage VCC of approximately 5 volts in order to be TTL compatible and is connected at one side of the circuit at line 85 and to ground potential at the other line 86, which corresponds to the substrate 10 of FIG. 1 being connected to ground potential. Another load resistor 87 is connected between line 85 and node 72 and completes the trans-impedance amplifying portion of the circuit.
The operational amplifier includes an NPN bipolar transistor 90 having its collector and emitter terminals connected between a node 92 and line 86. A resistor 94 is connected between node 96 and the base of transistor 90. A resistor 98 is connected between nodes 72 and 96, and resistor 100 is connected between node 96 and 92. A load resistor 102 is connected between the supply voltage at line 85 and the collector of transistor 90.
The output amplifying stage comprises an output transistor 110 having a Schottky-barrier diode 112 connected between its base and collector terminals. The Schottky-Barrier diode is not a necessary element of the present invention but in some applications can be used to optimize operation. The specific transistor Schottky-barrier diode arrangement is disclosed in U.S. Pat. No. 3,649,883, issued March 14, 1972, and assigned to the same assignee of the present invention. A resistor 114 is connected between node 92 and the base terminal of transistor 110, and an optional load resistor 116 is connected between the supply line 85 and the collector of transistor 110 at node 118 which also constitutes the voltage output node which in turn is connected to voltage output line 120 for providing an output voltage Vout.
An undesirable parasitic capacitor 122 exists between node 118 and the cathode of diode detector 66 at node 124. The value of this parasitic capacitor 126 is normally less than 0.2 micro-micro farads and is typically in the order of 0.05 micro-micro farads.
In the preferred embodiment, the radiation source is depicted as an LED; however, other suitable radiation type sources can be employed.
OPERATION
Assuming that radiation 26 is emitted by the LED radiation source 18, approximately 6 - 10 microamperes (I1) is generated by the diode detector 66 assuming a drive current of approximately ten milliamps to the LED radiation source. This generated current discharges the substrate-epitaxial capacitor represented at 34 in FIG. 1 and also the shunt base-emitter capacitance of transistor 70 so as to turn transistor 70 off. This causes the collector of transistor 70 at node 72 to rise until a feedback current through resistor 40 equals the detector current I1. With the flow of current I1 a feedback current I2 is created from node 72 through resistor 68 until I1 equals I2. This causes node 72 to rise in voltage in the amount equal to the product of I2 times the ohmic value of resistor 40 minus the small voltage drop at the base of transistor 70. Accordingly, a detected current I1 is converted to a voltage at node 72 and thus the term trans-impedance amplifier. The voltage generated at node 72 is employed to drive the operational amplifier stage 83. Prior to the incident of radiation on diode 66, and assuming a beta of approximately 100 for transistor 70 about 250 microamps flows through resistor 87. The operational amplifier 83 possesses a gain of approximately eight, which is set by the ohmic ratio of resistor 100 over resistor 98 and the open loop voltage gain of transistor 90. The ratio of the emitter areas of transistor 90 over that of transistor 70 is set equal to approximatey 1.3 in order to compensate for their difference in respective emitter currents and the voltage drop across resistor 40 due to the base bias current for transistor 70.
Resistor 94 is added to compensate for a beta range 50 to 500 which normally would cause the base drive currents of transistors 70 and 90 to change drastically. Also, it is noted that because of this configuration, the base voltage bias of transistor 90 is temperature compensated with respect to that of the output of transistor 70. Resistor 102 compensates resistor 87 for temperature changes as well as for absolute values caused by processing tolerances. Resistor 114 which connects output node 92 from the operational amplifier 83 to the output transistor 110 is optional but in this particular embodiment is introduced to limit the slew rate of output transistor 110 in order that the parasitic feedback through capacitor 122 to the detector diode 66 at node 124 does not cause spurious oscillations during switching.
As previously discussed the option of an output transistor 110 with a Schottky-barrier recombination ring is optional in order to reduce storage times for certain high speed applications. However, for data rates in the range of one megahertz, this configuration is unnecessary.
Node 92 drops approximately 400 millivolts when node 72 rises 50 millivolts, thus transistor 110 is turned off so as to generate an output voltage Vout approximately equivalent to VCC.
When the light emitting diode is turned off, the capacitance shown in FIG. 1 as element 34 is recharged through resistor 40 causing node 124 to rise in voltage, causing transistor 70 to turn on more which causes node 72 to drop in voltage. This in turn causes node 92 to rise causing output transistor 110 to be turned on by base drive current through resistor 114. Thus, the output voltage goes to approximately ground potential or more specifically, 150 millivolts which is the collector-to-emitter saturation voltage. The generated diode current I1 and output voltage waveforms for the present embodiment are illustrated in FIG. 3.
The exact values of resistors are unimportant, since the circuit is designed primarily to be sensitive to the ratio of resistors only. Furthermore, the overall circuit performance is relatively independent of supply voltages and capable of operating in a range of 2 volts to an excess of 10.0 volts. The value of 5.0 volts is arbitrarily selected in order that the output voltage Vout is compatible with TTL logic circuitry. The operational amplifying nature of the second stage is further improved performance wise, under certain circumstances, in that transistor 90 is quickly pulled out of saturation after the LED is overdriven and when the light emitting diode is turned off.
Another feature of the present circuit is that the detector capacitance is minimized by the use of the substrate-epi junction diode. The capacitance value can be further minimized by including a thin high resistivity N-layer at the PN junction 30 in the structure of FIG. 1 if even lower capacitance is desired (not shown).
While the invention has been particularly shown and described in reference to the preferred embodiments thereof, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the spirit and scope of the invention.
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An opto-coupler for isolating electrical signals constituted by an electrically responsive radiation source or emitting device, such as a light emitting diode (LED), optically coupling to a radiation sensitive detector for generating an electrical output in response to an electrical signal applied to the radiation source. The detector includes a PN junction positioned within a semiconductor body for generating maximum output current at high switching speeds with attendant minimization of capacitance. Increased values of detector current generation allow economical, reliable, and uncomplicated integrated circuit amplifying means to be responsive to the generated detector output current for generating increased current and voltage output signals, for example, TTL compatible, without speed degradation and readily implementable on a single small semiconductor integrated circuit chip or substrate. The detector chip and radiation or light emitting diode source can be readily mounted in an electronic package to provide an inexpensive opto-coupler unit.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an air-bag arrangement, and more particularly relates to an air-bag arrangement provided in a motor vehicle to give protection to an occupant of a front seat of the vehicle, such as the driver or a front seat passenger of the vehicle.
2. Description of the Prior Art
It has been proposed previously to provide an air-bag adapted to be inflated in the event that an accident should arise, the inflated air-bag being located in front of the driver or front seat passenger in a motor vehicle, to provide protection for the driver or passenger. A problem with such air-bags is that, in certain situations, when the air-bag has been deployed and the occupant moves forwardly towards the air-bag, as a consequence of deceleration of the vehicle during an accident, the neck of the occupant of the vehicle may be moved rearwardly, relative to the torso, thus injuring the occupant of the vehicle. The present invention seeks to provide an improved air-bag arrangement.
SUMMARY OF THE INVENTION
According to this invention there is provided an air-bag arrangement in a motor vehicle, the air-bag arrangement incorporating an air-bag initially stored within a housing, and means adapted to inflate the air-bag, so that the air-bag, when inflated, occupies a position generally in front of an occupant of a front seat of the vehicle, and between the occupant of the front seat of the vehicle and the windscreen or windshield of the vehicle, the air-bag being provided with a first region adapted to contact or lie immediately adjacent the interior of the windshield when the air-bag is inflated, and a second region located between the first region and the housing, the first region being provided with gas outlet means adapted to eject gas, from the interior of the air-bag, under pressure, to points between the first region of the air-bag and the inside surface of the windscreen or windshield.
Preferably the gas outlet means comprise a plurality of apertures in the air-bag providing a communication between the interior of the air-bag and the exterior of the air-bag.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which:
FIG. 1 is a diagrammatic side view illustrating an air-bag, following deployment thereof, at a position in front of a front seat passenger in a motor vehicle,
FIG. 2 illustrates the passenger impacting with the air-bag,
FIG. 3 illustrates the situation that can arise with a prior art air-bag shortly after the occupant has impacted with the air-bag,
FIG. 4 is a perspective view of a motor vehicle provided with an air-bag in accordance with the invention, with the air-bag in the deployed state, and
FIG. 5 is a view, corresponding to FIGS. 1 to 3 , illustrating the situation that exists shortly after the occupant of the vehicle has impacted with the inflated air-bag of FIG. 4 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring initially to FIG. 1 of the accompanying drawings, an interior part of a motor vehicle is illustrated. A seat 1 , such as the front seat, is provided, and a passenger 2 is located on the front seat. The passenger is retained in an initial position by a seat-belt 3 . The vehicle is provided with a dashboard 4 and a windscreen or windshield 5 . In FIG. 1 , an air-bag 6 , of a conventional design, is illustrated, the air-bag having been deployed from the dashboard 4 of the vehicle, as is conventional. The dashboard contains an air-bag housing in which the air-bag is stored before inflation. The inflated air-bag 6 is thus located between the passenger 2 and the dashboard 4 of the vehicle. The air-bag 6 is also located between the occupant 2 and the windscreen 5 . It is normal that a section of the air-bag is resting against the windscreen 5 .
FIG. 1 thus illustrates the situation that exists shortly after a frontal impact has been detected, and the air-bag 6 has been deployed.
Following the detection of the frontal impact and the initial deployment of the air-bag the vehicle will be decelerated, but the occupant 2 will continue to move forwardly, because of the inertia of the torso 7 and head 8 of the occupant. As the occupant continues to move forwardly, the seat-belt 3 will stretch and the torso 7 will impact with the inflated air-bag 6 and the head 8 will also impact with the inflated air-bag 6 . This is the situation shown in FIG. 2 . The air-bag, when this stage is reached, will be fully inflated. Now a substantial area 9 of the forward section 13 of the air-bag will be pressed against the windscreen 5 located above the dashboard 4 , whilst a lower portion 10 of the air-bag will be pressed against the torso 7 of the occupant 2 of the seat 1 of the vehicle.
In a conventional air-bag, because the large surface area 9 is pressed against the windshield 5 , there is substantial friction between the area 9 and the windshield 5 , and thus the upper part of the inflated air-bag 6 is held stationary in the position that it occupies when inflated, even if subjected to a force that tends to move the air-bag.
The torso 7 of the occupant has a substantial momentum or inertia, and as the vehicle continues to decelerate, the torso 7 moves forwardly relative to the vehicle, compressing the inflated air-bag 6 , moving the portion 10 of the air-bag which is at a position remote from the area 9 forwardly. The load on the bag is increased and the pressure on the windscreen is increased thereby. The head 8 , of the occupant, does not have such a great inertia, and the head 8 of the occupant engages an upper part 11 of the air-bag which is very close to the region which is held stationary because of the friction existing between the area 9 and the windshield 5 . Thus the head 8 tends to be kept relatively stationary, whilst the torso 7 is permitted to move forwardly. This leads to a rearward flexing of the neck of the occupant 2 of the seat 1 , as can be seen in FIG. 3 . This is undesirable.
Turning now to FIG. 4 , it is to be appreciated that in the described embodiment of the invention, the air-bag 6 is provided, within the region 9 , that is to say the region that is to be pressed against the windshield 5 on inflation of the air-bag 6 , with a plurality of small apertures 12 . The small apertures 12 provide a communication between the interior of the air-bag and the exterior of the air-bag and thus permit the exit of gas from the interior of the air-bag. The gas is directed towards the inner surface of the windshield 5 and is consequently injected between the surface of the air-bag and the inner surface of the windscreen or windshield 5 . This tends to ensure that the air-bag 6 is biased away from the windshield 5 . When the pressure in the bag is increased by the occupant moving into the bag more gas will be forced out through the apertures 12 . The effect is, in some respects, similar to that of “hovercraft”. The high pressure gas ejected from the air-bag between the air-bag and the windscreen or windshield tends to separate the air-bag from the windscreen or windshield which is illustrated by the space 14 , thus at least reducing the friction between the airbag and the windscreen or windshield. In a typical situation because the area 9 of the air-bag 6 is spaced slightly from the windshield 5 , there is no friction or grip between the air-bag 6 and the windshield 5 .
To obtain a best possible reduction of the friction with a minimum of gas leaving the bag, the openings in the area 9 can be arranged asymmetrically, for example, by larger openings in the center or by the openings 12 arranged closer to each other in selected areas.
Thus, as can be seen from FIG. 5 , when the torso 7 and head 8 of the occupant 2 of a seat 1 in a vehicle provided with an air-bag 6 in accordance with the invention impacts with the air-bag, the upper part of the air-bag actually moves forwardly and downwardly in response to the pressure applied thereto by the head 8 of the occupant 2 . The area 9 of the air-bag, thus “slides” across the interior surface of the windscreen or windshield 5 . Therefore the risk of the neck of the occupant of the vehicle flexing rearwardly is substantially minimised.
Whilst the invention has been described with specific reference to an air-bag provided to protect a front seat passenger in a motor vehicle, it is to be appreciated that in an alternative embodiment of the invention, the air-bag may be intended to protect the driver of the vehicle. In such a situation the air-bag would be initially mounted within the hub of the steering wheel of the vehicle.
In this specification the term “comprising” means “including or consisting of” and the term “comprises” means “includes or consists of”.
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An air-bag arrangement incorporating an air-bag ( 6 ) and means adapted to inflate the air-bag, so that the air-bag occupies a position generally in front of an occupant ( 2 ) of a front seat of the vehicle, and between the occupant ( 2 ) of the front seat of the vehicle and the windscreen or windshield ( 5 ) of the vehicle, that part of the air-bag ( 6 ) located to contact the interior of the windshield ( 5 ), when the air-bag ( 6 ) is inflated being provided with gas outlet means to inject gas, under pressure, between part of the air-bag and the inside surface of the windscreen or windshield ( 5 ).
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an interchangeable lens that can be detachably attached to a camera body and that can carry out data communications with the camera body.
[0003] 2. Description of the Related Art
[0004] A conventional SLR camera system, in which a photographic lens is interchangeable, is used by combining a camera body and an interchangeable lens selected from among various interchangeable lenses, and accordingly, each interchangeable lens incorporates a memory (lens memory) into which lens data inherent in the interchangeable lens is written so that the camera body reads out this lens data from the lens memory to use this lens data for controlling a photographic operation at a time of exposure. For instance, in conventional zoom lenses such as disclosed in Japanese Unexamined Patent Publications 2002-244188 (hereinafter referred to as Patent Document 1) and 2002-258380 (hereinafter referred to as Patent Document 2), lens data is written into memory by a paging method for each focal length step because the lens data needs to be changed according to variations in focal length caused by a zooming operation. Upon the focal length of the zoom lens being changed, a page corresponding to the changed focal length is detected by a zoom code output device and designated via hardware, and thereupon the camera body reads in the data in this designated page from the lens memory without concern for variations in focal length caused by a zooming operation.
[0005] Additionally, in a conventional camera system in which a photographic lens is interchangeable, the interchangeable lens incorporates a controller (CPU) in the case where sophisticated capabilities such as an AF capability and a zooming capability are incorporated in the interchangeable lens. This conventional type of camera system is disclosed in Patent Documents 1 and 2 and Japanese Unexamined Patent Publication 2003-35924 (hereinafter referred to as Patent Document 3).
[0006] However, a conventional communication device which carries out data communications with a lens memory cannot carry out communications with a lens CPU even if capable of reading in lens data written in a lens memory. Therefore, when the conventional communication device carries out communications selectively with the lens memory and the lens CPU, communication lines are switched (in a manner as shown in Patent Documents 1 and 2), or the conventional communication device carries out communications via the lens CPU at all times (in a manner as shown in Patent Document 3).
[0007] However, in camera systems, it is desirable for the number of communication lines and signals, for use in communication between a camera body and an interchangeable lens mounted to the camera body, to be as small as possible, and it is undesirable to add any extra communication lines or signals in order to ensure compatibility between the camera body and the interchangeable lens.
[0008] On the other hand, the greater the number of sophisticated features in the camera body and/or in the interchangeable lens, the greater the amount of data and the greater amount of data processing is required, which increases the necessity for the camera body to read a zoom code and a distance code from the camera body in a short period of time. Moreover, conventionally, a zoom code and a distance code are used solely for page swapping and that the camera body cannot read a zoom code and a distance code directly from the interchangeable lens.
SUMMARY OF THE INVENTION
[0009] The present invention has been devised in view of the above described problems which arise in conventional interchangeable lenses, and provides an interchangeable lens used in a camera system in which a photographic lens is interchangeable, wherein the interchangeable lens is configured to allow selection between the lens memory and the lens CPU in the interchangeable lens with which the camera body carries out communications with no need to increase the number of signal lines; moreover, the interchangeable lens is configured to achieve a reduction in time for communication.
[0010] According to an aspect of the present invention, an interchangeable lens is provided, which can communicate with a camera body to which the interchangeable lens is detachably attached to exchange data of the interchangeable lens, the interchangeable lens including a logic IC serving as an interface via which the interchangeable lens communicates with the camera body; a memory which is provided independent of the logic IC, connected to the logic IC, and stores the data of the interchangeable lens; and a controller, connected to the logic IC, for controlling operations of the interchangeable lens. The logic IC selectively switches connections of terminals thereof with the memory and the controller for communication therewith upon receiving a communication signal from the camera body.
[0011] It is desirable for the interchangeable lens to include a zooming function; a zoom code detector which detects a zoom code by encoding each of a plurality of zooming ranges, into which a variable-focal-length range that varies by a zooming operation has been divided, as the zoom code; and a distance code detector which detects a distance code by encoding each of a plurality of object distance ranges, into which a variable-object-distance range that varies by a focus adjusting operation has been divided, as the distance code. The logic IC includes a plurality of input pins via which the logic IC inputs the zoom code and the distance code which are detected by the zoom code detector and the distance code detector, respectively. The logic IC transmits the zoom code and the distance code, which are set by the plurality of input pins, to the camera body upon receiving a read command as a communication signal from the camera body.
[0012] It is desirable for the logic IC to include a memory capacity set-pin for identifying a memory capacity of the memory. When transmitting the zoom code and the distance code which are set by the plurality of input pins to the camera body, the logic IC transmits information on the memory capacity of the memory to the camera body together with the zoom code and the distance code.
[0013] It is desirable for lens data corresponding to each of the zoom codes and each of the distance codes to be written in the memory beforehand. Upon receiving a memory communication command as a memory communication signal from the camera body, the logic IC switches the connections of the terminals thereof to the memory and selects a page of the memory which corresponds to the zoom code and the distance code that the logic IC inputs via the plurality of input pins to transmit lens data written in the page to the camera body.
[0014] It is desirable for the memory to be an EEPROM.
[0015] It is desirable for the interchangeable lens to be configured as a variable-focal-length lens.
[0016] In an embodiment, a camera system is provided, having a camera body and an interchangeable lens which can communicate with the camera body to which the interchangeable lens is detachably attached to exchange data of the interchangeable lens. The interchangeable lens includes a logic IC serving as an interface via which the interchangeable lens communicates with the camera body; a memory which is provided independent of the logic IC, connected to the logic IC, and stores the data of the interchangeable lens; and an in-lens controller, connected to the logic IC, for controlling operations of the interchangeable lens. The camera body includes a in-body controller which communicates with the interchangeable lens. The logic IC selectively switches connections of terminals thereof with the memory and the controller for communication therewith upon receiving a communication signal from the in-body controller.
[0017] According to the present invention, since the logic IC that serves as an interface between the interchangeable lens and the camera body switches connections of terminals thereof for communication selectively to the memory and the controller, the camera body is allowed to communicate selectively with the memory and the controller of the interchangeable lens with no need to increase the number of communication signals or the number of signal lines.
[0018] Moreover, according to the present invention, the camera body can read a zoom code and a distance code directly from the interchangeable lens.
[0019] The present disclosure relates to subject matter contained in Japanese Patent Application No. 2007-68582 (filed on Mar. 16, 2007) which is expressly incorporated herein in its entirety.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The present invention will be discussed below in detail with reference to the accompanying drawings, in which:
[0021] FIG. 1 is a block diagram showing the main components of an SLR camera system having an interchangeable lens according to the present invention;
[0022] FIGS. 2A and 2B show a first embodiment of memory maps of a memory incorporated in the interchangeable lens according to the present invention, wherein FIG. 2A shows a memory map of data in a conventional area of the memory and FIG. 2B shows a memory map of data in an extended area of the memory that uses a common-data extension mode;
[0023] FIGS. 3A and 3B show a second embodiment of the memory maps of the memory incorporated in the interchangeable lens according to the present invention, wherein FIG. 3A shows a memory map of data in a conventional area of the memory and FIG. 3B shows a memory map of data in an extended area of the memory that an indexed addressing mode;
[0024] FIG. 4 is a flow chart showing an embodiment of an AF process performed in an SLR camera system including the interchangeable lens according to the present invention;
[0025] FIG. 5 is a flow chart showing an embodiment of a lens communication process performed in the SLR camera system including the interchangeable lens according to the present invention;
[0026] FIG. 6 is a flow chart showing an embodiment of an extended lens communication process performed in the SLR camera system including the interchangeable lens according to the present invention;
[0027] FIG. 7 is a flow chart showing an embodiment of an LROM communication process performed in the interchangeable lens according to the present invention;
[0028] FIGS. 8A and 8B are timing charts showing a general overview of communications performed in the SLR camera system including the interchangeable lens according to the present invention;
[0029] FIGS. 9A , 9 B and 9 C are timing charts for lens CPU communication performed in the SLR camera system including the interchangeable lens according to the present invention, wherein FIG. 9A shows communications between the camera body and the interchangeable lens (lens interface IC), and FIGS. 9B and 9C each show communications between the lens interface IC and the lens CPU;
[0030] FIGS. 10A and 10B are timing charts for the LROM communication performed in the SLR camera system including the interchangeable lens according to the present invention, wherein FIG. 10A shows communications between the camera body and the interchangeable lens (lens interface IC) and FIG. 10B shows communications between the lens interface IC and an EEPROM;
[0031] FIG. 10C is a data table showing information on set-pins and the contents thereof;
[0032] FIG. 11A is a timing chart showing a set-pin reading process performed in the SLR camera system including the interchangeable lens of the present invention;
[0033] FIG. 11B is a data table showing an embodiment of the contents of set-pins; and
[0034] FIGS. 12A , 12 B and 12 C are timing charts showing a read/write process performed in the SLR camera system including the interchangeable lens of the present invention, wherein FIG. 12A shows operations for write enable, FIG. 12B shows operations for writing, and FIG. 12C shows operations for reading.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0035] An SLR camera system shown in FIG. 1 is composed of a camera body 10 and an interchangeable lens 50 which is detachably attached to the camera body 10 . The camera body 10 is provided with a camera CPU (in-body controller) 11 , a camera peripheral circuit 13 and a battery 15 . The camera CPU 11 comprehensively controls the overall operations of the SLR camera system, the camera peripheral circuit 13 performs auxiliary operations while carrying out communications with the camera CPU 11 , and the battery 15 supplies power to the camera CPU 11 , the camera peripheral circuit 13 , and the interchangeable lens 50 mounted to the camera body 10 .
[0036] On the other hand, the interchangeable lens 50 is provided with a lens CPU (in-lens controller) 51 , a lens peripheral circuit 53 , an EEPROM (lens memory) 55 and a lens interface IC (gate array) 57 . The lens CPU 51 controls the operation of the interchangeable lens 50 , the lens peripheral circuit 53 drives a built-in AF motor and other components incorporated in the interchangeable lens 50 under control of the lens CPU 51 , the EEPROM 55 serves as a nonvolatile memory in which lens data is stored, and the lens interface IC 57 serves as a logic IC which relays communications between the camera CPU 11 and the lens CPU 51 and between the camera CPU 11 and the EEPROM 55 . The electronic circuit and components including the lens CPU 51 , which are incorporated in the interchangeable lens 50 , operate with power supplied from the camera peripheral circuit 13 . In the present embodiment, SPI (Serial Peripheral Interface) is adopted as a communication mode for the EEPROM 55 .
[0037] The camera CPU 11 and the lens interface IC 57 are connected to each other via a reset/set terminal RESL, a clock terminal SCKL and a serial I/O terminal SIOL (see FIG. 1 ). The lens interface IC 57 operates in accordance with (in synchronization with) a serial clock signal output from the clock terminal SCKL and is configured to operate logically according to variations in the level of the reset/set terminal RESL and commands (serial communication signal) output from the serial I/O terminal SIOL.
[0038] Similar to conventional SLR cameras, the camera body 10 is provided with basic components such as a phase-difference AF sensor unit and a built-in AF motor. In addition to these basic components, the camera body 10 is further provided with an image sensor, similar to conventional digital SLR cameras. On the other hand, the interchangeable lens 50 is provided with basic components such as a zoom optical system, a diaphragm mechanism and a focus adjusting mechanism which are similar to those provided in conventional zoom lenses. The interchangeable lens 50 can further be provided therein with a built-in AF motor which drives the focus adjusting mechanism as a substitute for a manual operation or the built-in AF motor (not shown) of the camera body 10 .
[0039] The lens interface IC 57 is provided with a plurality of set-pins and uses one of these set-pins as a capacity set-pin (memory capacity set-pin EEP). The number of bytes required for the lens interface IC 57 to address the EEPROM 55 is changed in accordance with the level of the memory capacity set-pin EEP. Although addressing is possible with only one byte if the memory capacity is small, two bytes are required if the memory capacity is large. Accordingly, the memory capacity set-pin EEP is set to a low (“L”) level when addressing is performed using one byte, and the memory capacity set-pin EEP is set to a high (“H”) level when addressing is performed using two bytes. In this manner, since the number of bytes for addressing can be selected according to the memory capacity, the lens interface IC 57 can be made to comply with the memory capacity of the EEPROM 55 . In the present embodiment, SPI is adopted as a communication mode for the EEPROM 55 , and accordingly, a memory capacity equal to or smaller than 4 kilobits (addressing 9 bits) is regarded as a small memory capacity, and a memory capacity equal to or greater than 8 kilobits (addressing 10 bits) is regarded as a large memory capacity. Using the EEPROM 55 as a lens memory in which lens data on the interchangeable lens 50 is stored makes it possible to write and rewrite lens data into the EEPROM 55 after the installation thereof in the interchangeable lens 50 , which further enhances the versatility and convenience of the interchangeable lens 50 .
[0040] In the present embodiment, fixed data on the interchangeable lens 50 (fixed lens data) is allocated to the following set pins: lens type set-pins (first group of set-pins) LT 1 and LT 2 , lens capability set-pins (second group of set-pins) LD 0 through LD 7 , and shortest object distance set-pins (third group of set-pins) ND 0 through ND 4 , so that the lens type set-pins LT 1 and LT 2 serve as a group of fixed data set-pins, the lens capability set-pins LD 0 through LD 7 serve as another group of fixed-data set-pins, and the shortest object distance set-pins ND 0 through ND 4 serve as another group of fixed data set-pins. An example of the contents thereof is as shown in a data table of FIG. 10C . The lens type set-pins LT 1 and LT 2 provide lens type set-pin LT information for setting a lens type; the lens capability set-pins LD 0 through LD 7 provide lens capability set-pin LD information for setting capabilities of the interchangeable lens 50 such as AF, AF direction, macro and light projection; and shortest object distance set-pins ND 0 through ND 4 provide shortest object distance set-pin ND information which shows the shortest object distance.
[0041] Additionally, in the present embodiment, distance codes are allocated to three input pins DC 0 through DC 2 provided on the lens interface IC 57 , and zoom codes are allocated to eight input pins ZC 0 through ZC 7 provided on the lens interface IC 57 . The interchangeable lens 50 is provided therein with a distance code output device 61 which is connected to the input pins DC 0 through DC 2 . The distance code output device 61 makes it possible to detect the current object distance by dividing the range of the variable object distance (photographing distance) into a plurality of ranges and outputting distance codes for identifying the plurality of ranges, respectively, to the input pins DC 0 through DC 2 . The interchangeable lens 50 is provided therein with a zoom code output device 63 which is connected to the input pins ZC 0 through ZC 7 . The zoom code output device 63 makes it possible to detect the current focal length by dividing the range of the variable focal length (variable zooming range) into a plurality of ranges and outputting zoom codes (focal-length codes) for identifying the plurality of ranges, respectively, to the input pins ZC 0 through ZC 7 . Versatile codes regarding versatile data are allocated to four input pins GP 0 through GP 3 , and each of the input pins GP 0 through GP 3 sets a low/high signal depending on whether it is grounded or not.
[0042] A known distance code output device and a known zoom code output device are used as the distance code output device 61 and the zoom code output device 63 , respectively. For instance, the distance code output device 61 is made up of a code plate fixed to a movable lens barrel, or the like, which moves relative to a focusing lens group, and a brush which moves with the focusing lens group while sliding on the code plate. More specifically, the range of a code pattern formed on the code plate is divided into a number of ranges which makes it possible to identify the distance range from the closest object distance to the infinite object distance with 3 bits, and a distance code consisting of electrical 3-bit high/low signals generated by sliding contacts of resilient conductive strips of the brush with conductive portions of each of the divided ranges of the code pattern is allocated to each of the divided ranges of the code pattern. An electrical high/low signal, which corresponds to the range of code pattern with which the brush is in contact, is input to the input pins DC 0 through DC 2 as a distance code. Similarly, the zoom code output device 63 is made up of an 8-bit code plate and a brush, and an electrical high/low signal corresponding to the focal length range, which is generated by sliding contacts of resilient conductive strips of the brush with conductive portions of each of the divided ranges of the code pattern on the 8-bit code plate, is input to the input pins ZC 0 through ZC 7 as a zoom code.
[0043] The lens interface IC 57 is provided with a logic circuit which decodes the distance code of a combination of high/low settings of the distance-code input pins DC 0 through DC 2 , and the zoom code of a combination of high/low settings of the zoom-code input pins ZC 0 through ZC 7 to perform an address-designating process to address the corresponding page of the EEPROM 55 .
[0044] The camera body 10 can read out lens data from the EEPROM 55 stored in the page addressed by the distance-code input pins DC 0 through DC 2 and the zoom-code input pins ZC 0 through ZC 7 . The camera body 10 carries out communications with the EEPROM 55 by address-designation, performed by the lens interface IC 57 physically and sequentially, in accordance with the levels of the distance-code input pins DC 0 through DC 2 and the zoom-code input pins ZC 0 through ZC 7 .
[0045] Since a circuit incorporated in the interchangeable lens 50 can physically switch between the corresponding pages of the EEPROM 55 by a zoom code signal and a distance code signal, which vary by a zooming operation and a distance adjusting operation, respectively, the camera body 10 does not have to take charge of memory administration and can rapidly obtain lens data corresponding to the currently-set focal length and the currently-set object distance.
[0046] In each page of the EEPROM 55 , lens data corresponding to a combination of an object distance and a focal length is written. In the EEPROM 55 of the interchangeable lens 50 , a memory area is provided in which data corresponding to a zoom code is written in each page by a paging method that is adopted by conventional interchangeable lenses (see FIGS. 2A and 3A ). Additionally, in these embodiments, a memory area for one page is allocated to one zoom code. Each page provides a capacity of 16 bytes from PD 0 through PD 15 , and predetermined lens data is allocated to each page in units of two bytes. In the memory maps shown in FIGS. 2A through 3B , there are eight pages 00 through 07 in total, and accordingly, a page set according to zoom data is designated, and data written in this page is read out according to a conventional communication mode.
[0047] In the present embodiment, since addressing can be performed using two bytes, the number of pages can further be increased. For instance, the range of variable focal lengths can further be divided into a large number of ranges. Therefore, appropriate data according to the focal length can be stored in the EEPROM 55 even in an interchangeable zoom lens having a high zoom power. In this case also, the communication algorithm of the camera body does not have to be changed.
[0048] FIG. 2B shows a first embodiment of memory maps of the EEPROM 55 that uses a common-data extension mode. Data on the date and time of manufacture and the version of ROM is written in an area of 4 bytes in an extended area of the memory from the end address thereof, and an area in which new common data is written is set in another area of the extended area lower than the memory area of 4 bytes. Common data can be read by addressing from the end address of the memory regardless of the memory capacity due to the common data being sequentially arranged from the end address of the memory. For instance, although the total memory capacity is 256 bytes (2 kilobits) in the case shown in FIG. 2B , the end address FFh of 256 bytes can be addressed by the end address 1FFh in 1-byte addressing (9 bits). If the total memory capacity becomes insufficient due to an increase in number of pages or an increase of common data from the state of memory location shown in FIG. 2B , the EEPROM 55 can deal with this situation simply by changing the 2 kilobit memory to a 4 kilobit memory and arranging common data in a similar manner from the end address (1FFh).
[0049] FIG. 3B shows a second embodiment of the memory maps of the EEPROM 55 that uses an indexed addressing mode that makes it possible to further add data to zoom data controlled according to a paging method. In the indexed addressing mode, an area of 8 bytes (addresses FFF8h through FFFFh) of the most significant address of the memory is provided as an index area, and the start address of additional zoom data and the number of bytes of the additional zoom data, and the start address of additional common data and the number of bytes of the additional common data, are set as index data in this index area. By reading in this index data, the addresses and the data length of the additional zoom data and the additional common data can be determined, and the reading of these data becomes possible.
[0050] Although the memory capacity in this example is the maximum capacity of 512 kilobits that 2-byte addressing can deal with, index data of 8 bytes arranged from the end address can be read at all times by addressing addresses FFF8h through FFFFh if the capacity of the memory is equal to or greater than 8 kilobits: the minimum capacity for 2-byte addressing. Of course, it is possible to adopt the indexed addressing mode in a similar manner in the case of 1-byte addressing simply by changing the addressing of the addresses to 1F8h through 1FFh.
[0051] In the first embodiment of the memory maps shown in FIG. 2B , the amount of movement of a focal plane per pulse of AF pulses (Δfocal plane/AF pulse) is set as additional zoom data for each range of a plurality of focal length ranges. The version of ROM data and the date/month/year of manufacture are set as common data. These data are read by computing addresses based on the start address and the number of bytes of data which are read from the index data and also based on a zoom code (and a distance code if necessary) obtained via a code-plate-information communication.
[0052] According to this paging method, in the interchangeable lens 50 , only the page data of the EEPROM 55 which corresponds to a zoom code can be read out of the EEPROM 55 when the interchangeable lens 50 is mounted to a conventional camera body which is non-compatible with either the common-data extension mode or the indexed addressing mode. When the interchangeable lens 50 is mounted to a camera body compatible with the common-data extension mode or the indexed addressing mode, additional data set according to the common-data extension mode or the indexed addressing mode can be read out of the EEPROM 55 in addition to the page data of the EEPROM 55 which corresponds to a zoom code.
[0053] An AF process including a process of reading the above described data in this camera system will be hereinafter discussed with reference to the flow charts shown in FIGS. 4 through 7 and the timing charts shown in FIGS. 8A through 12C . The processes shown in FIGS. 4 through 6 are controlled by the camera CPU 11 in the camera body 10 . The process shown in FIG. 7 is a sequence of operations of the lens interface IC 57 in the interchangeable lens 50 .
[0054] The AF process shown in FIG. 4 corresponds to a subroutine included in a main process performed in a conventional camera system, and is called up from the main process immediately after, e.g., a photometering switch is turned ON by a half depression of the release button (not shown) of the camera body 10 . The AF process will be discussed with reference to FIGS. 8A and 8B that show an overview of the timing of main communications performed in the camera system shown in FIG. 1 .
[0055] In the AF process, firstly the camera body 10 carries out communication (lens communication) with the interchangeable lens 50 (step S 101 ). In this lens communication, only LROM (lens ROM) communication, i.e., ‘fixed data communication’ is carried out. Namely, the camera CPU 11 reads page data, from the interchangeable lens 50 , stored in the EEPROM 55 which is addressed by the input pins DC 0 through DC 2 and the input pins ZC 0 through ZC 7 .
[0056] Subsequently, it is determined whether or not the interchangeable lens mounted to the camera body 10 is an interchangeable lens compatible with either the common-data extension mode or the indexed addressing mode, i.e., whether or not the interchangeable lens mounted to the camera body 10 is the interchangeable lens 50 that is compatible with an extended lens communication (step S 103 ). If the interchangeable lens mounted to the camera body 10 is compatible with the extended lens communication (if YES at step S 103 ), the extended lens communication is carried out (step S 105 ). In the extended lens communication, the camera CPU 11 refers to index data to read the data from the EEPROM 55 which is located at the address corresponding to the distance code and the zoom code. If the interchangeable lens mounted to the camera body 10 is not compatible with the extended lens communication (if NO at step S 103 ), control skips step S 105 , i.e., proceeds from step S 103 to step S 107 .
[0057] Subsequently, focus detection data (data on a pair of object images) is received from the aforementioned AF sensor unit (step S 107 ) and a defocus calculation operation by phase difference is carried out to determine a defocus amount (step S 109 ). Thereafter, it is determined whether or not an in-focus state has been obtained based on the defocus amount thus determined (step S 111 ), and the AF process is completed if an in-focus state has been obtained (if YES at step S 111 ). If an in-focus state has not been obtained (if NO at step S 111 ), operations from step S 113 onwards are performed.
[0058] At step S 113 the number of AF drive pulses and the driving direction of the focusing lens group (AF motor) which are necessary for bringing a main object into focus are calculated based on the determined defocus amount, and if lens data (A focal plane/AF pulse) according to the object distance has been received via the extended lens communication performed at step S 105 , the number of AF drive pulses is adjusted based on this lens data. Subsequently, it is determined whether or not the interchangeable lens mounted to the camera body 10 incorporates the lens CPU 51 and the AF motor (step S 115 ). If no AF motor is incorporated in the interchangeable lens mounted to the camera body 10 (if NO at step S 115 ), the built-in AF motor of the camera body 10 is driven to rotate in the driving direction determined at step S 113 by a few pulses (step S 121 ), and control returns to step S 107 . The above described loop process from step S 107 to step S 121 via steps S 109 , S 111 (if NO thereat), S 113 and S 115 (if NO thereat) is repeated unless an in-focus state is obtained, and the AF process ends upon an in-focus state being obtained (if YES at step S 111 ).
[0059] If the interchangeable lens mounted to the camera body 10 is the interchangeable lens 50 that incorporates an AF motor (if YES at step S 115 ), the camera body 10 carries out communication (lens communication) with the interchangeable lens 50 to send data on the driving direction and the adjusted number of drive pulses to the interchangeable lens 50 to make the lens CPU 51 drive the built-in AF motor of the interchangeable lens 50 (step S 117 ). Subsequently, the camera CPU 11 waits for a built-in-motor-drive termination signal that is output from the lens CPU 51 via a communication with the interchangeable lens 50 (step S 119 ). Upon the camera CPU 11 receiving the built-in-motor-drive termination signal, control returns to step S 107 . The above described loop process from step S 107 to step S 119 via steps S 111 (if NO thereat), S 113 , S 115 (if YES thereat) and S 117 is repeated unless an in-focus state is obtained, and the AF process ends upon an in-focus state being obtained (if YES at step S 111 ). The lens CPU 51 drives the built-in AF motor of the interchangeable lens 50 by an amount corresponding to the AF drive pulses received from the camera body 10 , and outputs the aforementioned built-in-motor-drive termination signal to the camera CPU 11 via the lens interface IC 57 upon completion of the drive of the built-in AF motor of the interchangeable lens 50 .
[0060] The lens communication performed as steps S 101 , S 117 and S 119 will be hereinafter discussed in detail with reference to the flow chart shown in FIG. 5 and the timing charts shown in FIGS. 9A through 11 .
[0061] In the lens communication process, firstly the camera body 10 carries out a fixed data communication (lens ROM communication) with the interchangeable lens 50 mounted to the camera body 10 to read the lens data from the EEPROM 55 which corresponds to the distance code and the zoom code (step S 201 ).
[0062] Subsequently, it is determined whether or not new communication can be carried out between the camera body 10 and the interchangeable lens 50 (step S 203 ). If the new communication cannot be carried out, control returns. If the interchangeable lens 50 is of a type which allows the camera body 10 to carry out the new communication with the interchangeable lens 50 , the following additional three communications become available: lens CPU communication that is performed between the camera CPU 11 and the lens CPU 51 , EEPROM communication that is performed between the camera CPU 11 and the EEPROM 55 , and the aforementioned code-plate-information communication via which the camera CPU 11 receives information on the code plate of the distance code output device 61 from the lens interface IC 57 . If the new communication can be carried out between the camera body 10 and the interchangeable lens 50 (if YES at step S 203 ), it is determined which of the aforementioned three communications (lens CPU communication, EEPROM communication and code-plate-information communication) is to be utilized as a means of communication (step S 205 ). Subsequently, according to the type of communication utilized, the communication processes described below are selectively performed. One of the aforementioned three communications to be utilized as a means of communication and one of the communication processes described below to be performed are determined according to the states of the camera body 10 and the interchangeable lens 50 .
[Lens CPU Communication]
[0063] Operations performed when it is determined at step S 205 that the type of communication to be utilized is the lens CPU communication will be hereinafter discussed with reference to the timing chart shown in FIG. 9A . FIG. 9A shows a timing chart for communications between the camera body 10 and the lens interface IC 57 . In the lens CPU communication, the reset/set terminal RESL is first set to a low level before being subsequently set to a high level in order to initialize high/low settings of the lens interface IC 57 (step S 211 ). Thereafter, a CPU command is sent to the lens interface IC 57 from the serial I/O terminal SIOL in synchronization with a serial clock signal output from the clock terminal SCKL (step S 213 ), and subsequently, a CPU communication is performed to send and receive data corresponding to the aforementioned CPU command to and from the lens interface IC 57 (step S 215 ), and control returns.
[0064] The CPU command output at step S 213 is composed of two bytes, and the lens CPU 51 interprets the two bytes of information (which is input from the time the level of the reset/set terminal RESL rises to a high level after falling to a low level) as a command, and interprets bytes of information subsequent to the two bytes as data. The number of bytes of the received data is predetermined by this command. The data input/output direction is determined by the least significant bit (LSB) in the second byte of the CPU command. The data input/output direction is the direction from the camera body 10 to the interchangeable lens 50 if the least significant bit (LSB) is “0” and the direction from the interchangeable lens 50 to the camera body 10 if the least significant bit (LSB) is “1”. FIGS. 9B and 9C are timing charts for communications between the lens CPU 51 and the lens interface IC 57 , wherein FIG. 9B shows the timing when the lens CPU 51 inputs data from the camera CPU 51 via the lens interface IC 57 , and FIG. 9C shows the timing when the lens CPU 51 outputs data to the camera CPU 11 via the lens interface IC 57 .
[EEPROM Communication]
[0065] Operations performed when it is determined at step S 205 that the type of communication to be utilized is the EEPROM communication will be hereinafter discussed with reference to the timing charts shown in FIGS. 12A through 12C . In the EEPROM communication, the reset/set terminal RESL is first set to a low level before being subsequently set to a high level to initialize high/low settings of the lens interface IC 57 (step S 221 ).
[0066] Subsequently, an EEPROM command is sent to the lens interface IC 57 to switch connections of terminals thereof for communication to the EEPROM 55 (step S 223 ). This switching brings the camera CPU 11 into a state (EEPROM communication state) where the camera CPU 11 can carry out communications directly with the EEPROM 55 .
[0067] Subsequently, the reset/set terminal RESL is set to a low level (step S 225 ), an EEPROM communication is performed (step S 227 ), and control returns. In the EEPROM communication, the camera CPU 11 directly performs the read/write control of the EEPROM 55 and can read from and write into the EEPROM 55 via addressing by the camera CPU 11 .
[0068] In the EEPROM communication, when writing data into the EEPROM 55 , the camera CPU 11 firstly outputs a write-enable signal (see FIG. 12A ). Subsequently, the camera CPU 11 outputs a write command, a high-order write address, a low-order write address and write data, and thereafter raises the level of the reset/set terminal RESL to a high level (see FIG. 12B ). The sequence of these operations makes direct writing of data associated with high and low addresses of the EEPROM 55 into the EEPROM 55 possible.
[0069] In the EEPROM communication, the camera CPU 11 does not need to output the write-enable signal when reading data in from the EEPROM 55 . After entering the state of the EEPROM communication, the camera CPU 11 outputs a read command, a high-order read address and a low-order read address, and thereafter the camera CPU 11 can receive data in synchronization with a serial clock signal. Upon completion of the communication, the camera CPU 11 raises the level of the reset/set terminal RESL to a high level (see FIG. 12C ). The sequence of these operations allows direct reading of data associated with high and low addresses of the EEPROM 55 from the EEPROM 55 .
[0070] These sequences for read/write control of the EEPROM 55 conform to the SPI communication mode.
[Code-Plate-Information Communication]
[0071] Operations performed when it is determined at step S 205 that the type of communication to be utilized is the code-plate-information communication will be hereinafter discussed with reference to the timing chart and the diagram shown in FIGS. 11A and 11B , respectively. FIG. 11A is a timing chart for the code-plate-information communication, and FIG. 11B is a data mapping table. In the code-plate-information communication, the reset/set terminal RESL is first set to a low level before being subsequently set to a high level to initialize high/low settings of the lens interface IC 57 (step S 231 ), and subsequently, a code-plate-information read command is sent to the lens interface IC 57 to enable the camera CPU 11 to read information on the code plate of the distance code output device 61 (step S 233 ). Subsequently, after the reset/set terminal RESL is set to a low level (step S 235 ), the camera CPU 11 outputs a serial clock signal to receive information on the code plate, and control returns upon receiving information on the code plate (step S 237 ). In the code-plate-information communication, the camera CPU 11 inputs the levels of the memory capacity set-pin EEP, the distance-code input pins DC 0 through DC 2 , the versatile-code input pins GP 0 through GP 3 , and the zoom-code input pins ZC 0 through ZC 0 through ZC 7 ; data on the first byte is received as data on the capacity of the EEPROM 55 , distance-codes and versatile-code signals; and data on the second byte is received as data on zoom information (see FIG. 11B ).
[Extended Lens Communication]
[0072] The extended lens communication that is performed at step S 105 will be discussed in detail with reference to the flow chart shown in FIG. 6 . The extended lens communication is a communication process performed by a protocol equivalent to the protocol used for the EEPROM communication. The common-data extension mode in the extended lens communication is carried out by sequentially reading a prescribed number of bytes from the end address of the EEPROM 55 . The number of bytes is controlled on the camera body 10 side according to the ROM version (data of FCh and FDh) (see FIG. 2B ). The remaining mode in the extended lens communication, i.e., the indexed addressing mode will be discussed hereinafter.
[0073] In the extended communication mode, firstly the camera body 10 carries out the code-plate-information communication (see steps S 231 through S 237 in FIG. 5 ; FIGS. 11A and 11B ) with the interchangeable lens 50 (the lens interface IC 57 ) to read data on the memory capacity set-pin EEP to determine whether or not the capacity of the EEPROM 55 is equal to or smaller than 4 kilobits or is equal to or greater than 8 kilobits (step S 301 ).
[0074] Subsequently, the EEPROM communication is carried out to read data in the indexed portion of the EEPROM 55 (step S 303 ). In the present embodiment, 4 bytes from the end address in the EEPROM 55 are fixed as index data (see FIG. 3B ). This index data can be read by the memory capacity set-pin EEP regardless of the actual capacity of the EEPROM 55 by addressing the end address as FFFFh (if the capacity of the EEPROM 55 is equal to or greater than 8 kilobits) or 1FFh (if the capacity of the EEPROM 55 is equal to or smaller than 4 kilobits). Communication with the EEPROM 55 is performed by the algorithm at steps S 221 through S 227 and the sequence according to the timing charts shown in FIGS. 12A , 12 B and 12 C.
[0075] The camera CPU 11 analyzes the read data in the indexed portion to calculate the address and the capacity of extended data (step S 305 ).
[0076] Subsequently, the code-plate-information communication is again performed to obtain the distance code detected by the distance code output device 61 and the zoom code detected by the zoom code output device 63 (step S 307 ).
[0077] The extended data is read from the address corresponding to the distance code and the zoom code which are obtained at step S 307 (step S 309 ), and control returns.
[LROM Communication Process in the Interchangeable Lens]
[0078] The LROM communication process that is performed in the interchangeable lens 50 will be hereinafter discussed in detail with reference to the flow chart shown in FIG. 7 , and the timing charts and the table shown in FIGS. 10A , 10 B and 10 C. FIG. 10A is a timing chart on the camera body 10 side (timing chart for communications between the camera body 10 and the lens interface IC 57 ), FIG. 10B is a timing chart on the interchangeable lens 50 side (timing chart for communications between the lens interface IC 57 and the EEPROM 55 ), and FIG. 10C is a data mapping table showing the corresponding relationship between data.
[0079] Upon the reset/set terminal RESL falling to a low level, the level of a terminal CSEE falls to a low level, and three bytes of set-pin data SP 0 through SP 2 are output in the communication for the first three bytes in synchronization with a clock signal output from the clock terminal SCKL. The set-pin data SP 0 through SP 2 are set by the lens type set-pins (first group of set-pins) LT 1 and LT 2 , lens capability set-pins (second group of set-pins) LD 0 through LD 7 and shortest object distance set-pins (third group of set-pins) ND 0 through ND 4 that show the shortest object distance, and the level of each set-pin is sequentially read and decoded by the lens interface IC 57 to be output therefrom.
[0080] Page data of the EEPROM 55 which is addressed by the zoom-code input pins ZC 0 through ZC 7 is read out by a communication of 16 bytes from the fourth byte onwards. The lens interface IC 57 outputs the clock signal input from the clock terminal SCKL to a terminal SCKEE, outputs a read command and address data to a terminal SIEE, and reads data which is output from a terminal SOEE. This read data is sent (transferred) to the camera CPU 11 via the serial I/O terminal SIOL.
[0081] FIG. 7 is a flow chart showing a sequence of operations in the lens interface IC 57 with respect to the LROM communication. However, the lens interface IC 57 in the present embodiment is a logic IC, and the process shown in FIG. 7 is physically processed.
[0082] The lens interface IC 57 performs the LROM communication according to (in synchronization with) a serial clock signal that the camera CPU 11 outputs to the clock terminal SCKL with the reset/set terminal RESL being set at a low level.
[0083] In the LROM communication process, firstly it is determined whether or not the level of the reset/set terminal RESL has fallen to a low level (step S 401 ). Namely, the lens interface IC 57 waits for the level of the reset/set terminal RESL to fall to a low level at step S 401 . Upon the level of the reset/set terminal RESL falling to a low level (if YES at step S 401 ), the lens interface IC 57 reads in zoom code (the levels of the input pins ZC 0 through ZC 7 ) and converts the zoom code into address data for the EEPROM 55 (step S 403 ).
[0084] The lens interface IC 57 reads in the level of the memory capacity set-pin EEP to determine the high/low state thereof (step S 405 ). The memory capacity set-pin EEP is set to a low level if the memory capacity is equal to or smaller than 4 kilobits and to a high level if the memory capacity is equal to or greater than 8 kilobits.
[0085] If the level of the memory capacity set-pin EEP is a low level (if Low at step S 405 ), in the communication for the first byte, the lens interface IC 57 does nothing to the EEPROM 55 and sends the lens type set-pin LT information to the camera CPU 11 (step S 411 ). In the communication for the second byte, the lens interface IC 57 sends a read command to the EEPROM 55 and sends the lens capability set-pin LD information to the camera CPU 11 (step S 413 ). In the communication for the third byte, the lens interface IC 57 sends to the EEPROM 55 the address of 1 byte that the lens interface IC 57 has converted from the read zoom code, and sends the shortest object distance set-pin ND information to the camera CPU 11 (step S 415 ). Thereafter, in the communication for the fourth byte to the nineteenth byte, the lens interface IC 57 receives data of the EEPROM 55 sequentially from the address thereof which the lens interface IC 57 has sent to the EEPROM 55 at step S 415 , and sends (transfers) the data thus received to the camera CPU 11 (step S 431 ). Upon completion of the transmission of this data to the camera CPU 11 , it is determined whether or not the level of the reset/set terminal RESL has risen to a high level (step S 433 ). Namely, the lens interface IC 57 waits for the level of the reset/set terminal RESL to rise to a high level at step S 433 . Upon the level of the reset/set terminal RESL rising to a high level (if YES at step S 433 ), the lens interface IC 57 ends the LROM communication process.
[0086] If the level of the memory capacity set-pin EEP is a high level (if High at step S 405 ), in the communication for the first byte the lens interface IC 57 sends a read command to the EEPROM 55 and sends the lens type set-pin LT information to the camera CPU 11 (step S 421 ). In the communication for the second byte, the lens interface IC 57 sends the EEPROM 55 a high-order address_H among the address data that the lens interface IC 57 has converted from the read zoom code at step S 403 (step S 423 ). In the communication for the third byte, the lens interface IC 57 sends the EEPROM 55 a low-order address_L among the address data that the lens interface IC 57 has converted from the read zoom code at step S 403 (step S 423 ), and sends the shortest object distance set-pin ND information to the camera CPU 11 (step S 425 ). Thereafter, in the communication for the fourth byte to the nineteenth byte, the lens interface IC 57 receives data of the EEPROM 55 sequentially from the addresses thereof designated by the high-order address_H and the low-order address_L that the lens interface IC 57 has sent to the EEPROM 55 at steps S 423 and 425 , respectively, and sends the data thus received to the camera CPU 11 (step S 431 ). Upon completion of the transmission of this data to the camera CPU 11 , the lens interface IC 57 waits for the level of the reset/set terminal RESL to rise to a high level at step S 433 . Upon the level of the reset/set terminal RESL rising to a high level (if YES at step S 433 ), the lens interface IC 57 ends the LROM communication process.
[0087] According to the above described embodiment of the interchangeable lens, in a camera system in which a photographic lens is interchangeable, communications with the interchangeable lens can be carried out in the camera body with no need to increase the number of signal lines, and the sophisticated capabilities of the interchangeable lens can be fully utilized. Moreover, the compatibility between the camera body and the interchangeable lens is ensured even for fixed data communications because a logic IC provided in the interchangeable lens as an interface between the interchangeable lens and the camera body carries out communications selectively with the lens memory and the lens CPU.
[0088] Furthermore, the interchangeable lens is capable of serving the need for a reduction in time for communication with the advancement of capability of the interchangeable lens because the camera body can read a zoom code, a distance code, and information on the memory capacity of the memory directly from the lens interface IC of the interchangeable lens.
[0089] Obvious changes may be made in the specific embodiment of the present invention described herein, such modifications being within the spirit and scope of the invention claimed. It is indicated that all matter contained herein is illustrative and does not limit the scope of the present invention.
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An interchangeable lens which can communicate with a camera body to which the interchangeable lens is detachably attached to exchange data of the interchangeable lens, includes a logic IC serving as an interface via which the interchangeable lens communicates with the camera body; a memory which is provided independent of the logic IC, connected to the logic IC, and stores the data of the interchangeable lens; and a controller, connected to the logic IC, for controlling operations of the interchangeable lens. The logic IC selectively switches connections of terminals thereof with the memory and the controller for communication therewith upon receiving a communication signal from the camera body.
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TECHNICAL FIELD
The present invention relates to a hand-held tool for installing and/or removing a fastener, and more particularly, to a hand-held tool for installing and/or removing a fastener when access to the fastener is limited, for example, when replacing a roofing shingle that may be positioned underneath another shingle.
BACKGROUND
The roofs of houses and other buildings are commonly covered with various types of overlapping shingles to protect the underlying structure from direct exposure to the elements. These shingles are installed in rows, starting at the lower edge of the roof and moving upward. Accordingly, each succeeding row of shingles partially overlaps the prior row and completely covers the fasteners that attach the prior row to the roof substructure.
Conventional roofing shingle materials include wood, slate, metal, tile, fiberglass and asphalt. Asphalt shingles represent the most widely used form of residential roofing and cover four out of every five homes in the United States today. Asphalt shingles are typically made from an organic or fiberglass base that is saturated with an asphalt coating and surfaced with weather resistant mineral granules. Accordingly, asphalt shingles are typically durable, versatile and economical. Furthermore, asphalt shingles are generally pliant when new, making them easy to install. Over time, however, the effects of aging and exposure to the sun harden asphalt shingles to the point that even modest flexing can cause the shingles to break or permanently deform.
Asphalt shingle roofs can last up to 20 years before replacement, and damage to individual shingles during this time (for example, due to high winds or human traffic) is not uncommon. A widespread problem faced by roofing contractors is to replace an individual damaged shingle without damaging the overlapping undamaged shingle in the process.
One conventional method for replacing shingles includes sliding a flat-bladed shovel-like device under the damaged shingle to pry loose the fasteners attaching the damaged shingle to the roof substructure. Unlike a conventional claw hammer, the flat-bladed device can access the fasteners without bending the overlapping undamaged shingle to the point that the undamaged shingle breaks.
Once the fasteners have been removed, the damaged shingle may be slipped out from under the overlapping undamaged shingle and a replacement shingle slipped in underneath the overlapping shingle. At this point, the contractor must generally use to a conventional hammer to install the fasteners in the replacement shingle. Because it is desirable to cover the installed fasteners with the overlapping undamaged shingle, installation requires positioning the fastener on the replacement shingle while simultaneously bending the overlapping undamaged shingle far enough back to allow the contractor to strike the fastener with the hammer. Bending the undamaged shingle in this manner often breaks the undamaged shingle, forcing the user to repeat the entire process for two damaged shingles instead of just one.
SUMMARY OF THE INVENTION
The present invention is directed to methods and apparatuses for installing and/or removing fasteners. In one aspect of the invention, the apparatus can include a tool body with a fastener engagement portion toward a first end, a fastener removal portion toward a second end, and an impact surface located between the two ends. The fastener engagement portion can be offset from the impact surface in two directions and can have at least one fastener contact surface that is offset from and at least approximately parallel to the impact surface. The fastener engagement portion can be configured to releasably engage a fastener to install the fastener in a workpiece when a force is applied to the impact surface of the body. The fastener removal portion can also be offset from the impact surface in two directions, and can be configured to releasably engage an installed fastener to remove the fastener from a workpiece when a force is applied to the body.
In one aspect of the invention, the fastener engagement portion can further include first and second fastener guide surfaces. The first and second guide surfaces can be in a common plane and can be spaced apart from the fastener contact surface by a first gap distance sized to removably receive the head of a fastener. The first and second fastener guide surfaces also being spaced apart from each other by a second gap distance sized to removably receive the shank of the fastener. In a further aspect of the invention, the fastener removal portion can have first and second fingers extending away from the impact surface. The first finger of the fastener removal portion can include a first interior edge and the second finger can further include a second interior edge. The first and second interior edges can be in a common plane and can define a tapering gap that is sized to removably receive the shank of an installed fastener. In a still further aspect of the invention, the fastener removal portion toward the second end can be replaced with a scraper portion, a G-shaped pry-hook portion, or another fastener engagement portion, or the fastener removal portion can be eliminated.
In another aspect of the invention, a method for removing a fastener from a workpiece can include engaging a fastener between a first and second finger of an offset fastener removal portion of a fastener handling tool and applying a force to the tool body to remove the fastener from the workpiece. In a further aspect of the invention, the method can include engaging a fastener with an offset fastener engagement portion of a fastener handling tool inserting the offset fastener engagement portion into a confirmed space, positioning the engaged fastener on the workpiece, exposing an impact surface of the tool, and impacting the impact surface to drive the fastener into the workpiece.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a rear isometric view of a fastener installation and removal tool positioned to install a fastener in a replacement roofing shingle that is located underneath an installed shingle in accordance with an embodiment of the invention.
FIG. 2 is an enlarged rear isometric view of the fastener installation and removal tool shown in FIG. 1 positioned to remove a fastener from a damaged shingle that is located underneath an installed shingle.
FIG. 3 is an enlarged front isometric view of a fastener engagement portion of the tool and fastener shown in FIG. 1 .
FIG. 4 is an enlarged side elevation view of the fastener engagement portion of the tool and fastener shown in FIG. 1 .
FIG. 5 is an enlarged front elevation view of the fastener engagement portion of the tool and fastener shown in FIG. 1 .
FIGS. 6A, 6 B, 6 C and 6 D are isometric views of fastener installation tools having tool devices in accordance with other embodiments of the invention.
FIG. 7 is an isometric view of a fastener installation and removal tool having a non-offset impact surface in accordance with another embodiment of the invention.
FIG. 8 is an isometric view of a fastener installation and removal tool positioned to install a fastener in a replacement roofing shingle that is located underneath an installed shingle in accordance with yet another embodiment of the invention.
FIG. 9 is an isometric view of a fastener installation and removal tool having coupled portions in accordance with still another embodiment of the invention.
DETAILED DESCRIPTION
An apparatus and method for installing and/or removing fasteners is described herein. One embodiment of the invention includes a tool and method for installing fasteners in a replacement roofing shingle without damaging the previously installed overlapping shingle. Many specific details of certain embodiments of the invention are set forth in the following description and in FIGS. 1-9 to provide a thorough understanding of such embodiments. One of ordinary skill in the art, however, will understand that the present invention may have additional embodiments, or that the invention may be practiced without several of the details described in the following description.
FIG. 1 is a rear isometric view of a hand-held fastener installation and removal tool 101 positioned to install a new fastener 140 a in a workpiece, such as a replacement shingle 180 , without damaging a previously installed shingle 181 . The tool 101 can also be used to remove fasteners and damaged shingles from beneath the previously installed shingle 181 without damaging the previously installed shingle 181 . Accordingly, in one embodiment, the installation and removal tool 101 has a fastener engagement portion 110 toward a first end 150 , and a fastener removal portion 120 toward a second end 160 . An impact surface 130 is located between the fastener engagement portion 110 and the fastener removal portion 120 . As shown in FIG. 1, the fastener engagement portion 110 is offset from the impact surface 130 in a first direction 151 and in a second direction 152 transverse to the first direction 151 . Similarly, the fastener removal portion 120 is offset from the impact surface 130 in the second direction 152 and in a third direction 161 transverse to the second direction 152 . The impact surface 130 of the tool 101 is shaped to be struck with a conventional hammer 184 or other tool to provide the impact required to drive the fastener 140 a through the replacement shingle 180 and into a roof substructure 183 . In one embodiment, the tool 101 can include a handle portion 102 between the impact surface 130 and the second end 160 for grasping and maneuvering the tool 101 .
In one embodiment, the tool 101 may be cast in steel and finish machined. In other embodiments, the tool 101 may be forged or machined from steel. In still further embodiments, the tool 101 can include materials other than steel having suitable strength and stiffness.
FIG. 2 is an enlarged rear isometric view of the tool 101 with the fastener removal portion 120 positioned to remove an installed fastener 140 b from a workpiece such as a damaged shingle 182 . In one embodiment, the fastener removal portion 120 has a first finger 210 and a second finger 220 that both extend generally away from the impact surface 130 in the third direction 161 . The first finger 210 has a downwardly facing first heel surface 213 and a first interior surface 211 that are connected by a first interior edge 212 . The second finger 220 has a downwardly facing second heel surface 223 and a second interior surface 221 connected by a second interior edge 222 . As shown in FIG. 2, the first and second interior edges 212 and 222 define a tapering gap 201 . In one embodiment, the gap 201 tapers by an angle of from about 10 to about 30 degrees, and in another embodiment, the taper angle is about 14.25 degrees. In other embodiments, the gap 201 can taper by angles having other values.
In one embodiment, the gap 201 of the tool 101 is configured to releasably engage the installed fastener 140 b and extract the fastener 140 b from a damaged shingle 182 mounted to the roof substructure 183 . In one aspect of this embodiment, the fastener removal portion 120 of the tool 101 has a relatively low profile that projects by only a limited amount above the damaged shingle 182 . Accordingly, the installed fastener 140 b can be removed by inserting the fastener removal portion 120 beneath the installed shingle 181 without bending the installed shingle 181 to the point of breaking. In another aspect of this embodiment, the user can produce an upward force on the head of the fastener 140 b by applying a downward force to the impact surface 130 or the fastener engagement portion 110 of the tool 101 while the fingers 210 and 220 are engaged with the head of the fastener 140 b to pivot the tool 101 about the first and second heel surfaces 213 and 223 . This upward force extracts the fastener 140 b from the damaged shingle 182 and the roof substructure 183 . Alternatively, other tools may be used to extract the fastener 140 b from the damaged shingle 182 . In either embodiment, the damaged shingle 182 can then be removed and the replacement shingle 180 can be installed without breaking the previously installed shingle 181 by using the fastener engagement portion 110 .
FIG. 3 is a front isometric view of the fastener engagement portion 110 of the tool 101 and the fastener 140 a , positioned above the replacement shingle 180 . FIG. 4 is a side elevation view and FIG. 5 is a front elevation view of the fastener engagement portion 110 and the fastener 140 a shown in FIG. 3 . Referring to FIGS. 3, 4 , and 5 , the fastener engagement portion 110 has a first fastener contact surface 301 and a second fastener contact surface 390 that are offset from and at least approximately parallel to the impact surface 130 . The first fastener contact surface 301 can be offset from the impact surface 130 by a first distance 354 in the first direction 151 , and by a second distance 353 in the second direction 152 (FIGS. 3 and 4 ). In one embodiment, the first distance 354 can be between 0.5 and 5.0 inches, and the second distance 353 can be between 0.5 and 3.0 inches. In another embodiment, the second distance 353 can be about 1.64 inches. In other embodiments, the distances 353 and 354 can have other values that allow the tool to be operated in the manner described below.
The fastener engagement portion 110 also has a first fastener guide member 370 and a second fastener guide member 380 (FIGS. 3 and 5 ). The first fastener guide member 370 has a first fastener guide surface 310 and a first fastener alignment surface 320 . The second fastener guide member 380 has a second fastener guide surface 330 and second fastener alignment surface 340 . The first and second guide surfaces 310 and 330 are in a common plane and are spaced apart from the fastener contact surface 301 by a first gap distance 401 (FIGS. 4 and 5) to define a head slot 350 sized to accommodate a head 341 of the fastener 140 a . In one embodiment, the gap distance 401 can be about 0.10 inches, and in other embodiments, the distance can have other values that accommodate the head 341 . The first and second fastener alignment surfaces 320 and 340 oppose each other and are spaced apart by a second gap distance 501 (FIG. 5) to define a shank slot 360 sized to accommodate a shank 342 of the fastener 140 a . In one embodiment, the second gap distance 501 can be about 0.184 inches, and in other embodiments, the distance can have other values that accommodate the shank 342 . Accordingly, the head slot 350 is offset from and generally parallel with the impact surface 130 . The shank slot 360 intersects the head slot 350 and is transverse to the impact surface 130 .
Referring now to FIG. 3, the fastener engagement portion 110 of the tool 101 is configured to releasably engage the fastener 140 a so that it may be driven into the replacement shingle 180 when the impact surface 130 is struck with a conventional hammer or a similar tool. In one embodiment, the fastener 140 a is engaged with the fastener engagement portion 110 by removably positioning the shank 342 of the fastener 140 a between the first fastener alignment surface 320 and the second fastener alignment surface 340 , and by removably positioning the head 341 of the fastener 140 a between the fastener contact surface 301 and the first and second guide surfaces 310 and 330 . In an alternate embodiment, the surfaces 301 or 390 may also be magnetized to releasably engage the fastener 140 a prior to installation. In either embodiment, when the user strikes the impact surface 130 with a conventional hammer or a similar tool, the fastener contact surface 301 drives the fastener into the replacement shingle 180 . After the user drives the fastener 140 a part-way into the replacement shingle 180 (or completely through the replacement shingle 180 and part-way into the roof substructure 183 ), the user retracts the fastener engagement portion 110 to disengage it from the fastener 140 a , and then repositions the fastener engagement portion 110 so that the second fastener contact surface 390 is in contact with the head 341 of the fastener 140 a . The user then strikes the impact surface 130 with the hammer to drive the fastener 140 a the rest of the way into the roof substructure 183 , so that the head 341 of the fastener 140 a is now flush with the upper surface of the replacement shingle 180 .
In one embodiment of the invention, the user can operate the fastener installation and removal tool 101 to replace a damaged asphalt roofing shingle without damaging the previously installed overlapping shingle 181 in the process. For example, the user can remove the fastener 140 b attaching the damaged shingle 182 to the roof substructure 183 by using the fastener removal portion 120 of the tool 101 (FIG. 2 ). The user can then slide the replacement shingle 180 into position underneath the overlapping shingle 181 , and releasably engage the fastener engagement portion 110 of the tool 101 with the new fastener 140 a (FIG. 3 ). In one aspect of this embodiment, the fastener engagement portion 110 is offset from the impact surface 130 , and has a relatively low profile that projects only a limited amount above the replacement shingle 180 . Accordingly, the overlapping shingle 181 need only be lifted a lifting distance that is slightly more than the height of the fastener 140 a to create an opening where the fastener engagement portion 110 can be slipped underneath the overlapping shingle 181 to position the new fastener 140 a in the appropriate location on the replacement shingle 180 (FIG. 1 ). A conventional hammer 184 may then be used to strike the impact surface 130 of the tool 101 . When used in the manner described above, the tool 101 allows the replacement shingle 180 to be installed underneath the overlapping shingle 181 without lifting the overlapping shingle 181 so much that it breaks.
In other embodiments, the tool 101 can be used for other applications where access is limited. For example, the tool 101 can be used to install fasteners into a floor covering under an overhanging stair step, where the presence of the step creates a limited opening that makes the use of a conventional hammer alone impractical or awkward. In yet other embodiments, the tool 101 can have other configurations for fastener installation and other applications, as described below with reference to FIGS. 6A-9.
FIGS. 6A, 6 B, 6 C, and 6 D illustrate tools having second ends with other configurations in accordance with alternate embodiments of the invention. FIG. 6A is an isometric view of a tool 601 having a G-shaped pry-hook device 610 located toward the second end 160 for removing and/or loosening fasteners, or prying other objects. FIG. 6B is an isometric view of a tool 602 having a shingle remover or scraper 620 toward the second end 160 in accordance with another embodiment of the invention. FIG. 6C is an isometric view of a tool 603 wherein the fastener engagement portion 110 toward the first end 150 is a first fastener engagement portion, and the tool has a second fastener engagement portion 630 toward the second end 160 in accordance with yet another embodiment of the invention. FIG. 6D is an isometric view of a tool 604 in which the second end 160 simply supports the impact surface 130 in an offset position in accordance with still another embodiment of the invention. In other embodiments, the tool can have a second end with other configurations that can complement the function provided by the fastener engagement portion 110 .
FIG. 7 is an isometric view of a tool 701 having the fastener engagement portion 110 and the fastener removal portion 120 generally aligned with the impact surface 130 in accordance with another embodiment of the invention. Accordingly, the tool 701 can be easily stored when not in use. Conversely, an advantage of the tool 101 described above with reference to FIG. 1 is that the offset configuration can provide a more convenient impact surface for a hammer or a similar tool.
FIG. 8 is a rear isometric view of a tool 801 having an impact surface 830 that extends over the fastener engagement portion 110 . Accordingly, the impact surface 830 can provide a more direct line of action between the fastener 140 a and the point at which the hammer impacts the tool 801 . An advantage of this feature is that the tool 801 can be easier to hold during use. In another aspect of this embodiment, an upper surface 815 of the fastener engagement portion 110 can include graduation marks 820 to provide a guide for positioning the fastener 140 a under the overlapping shingle 181 .
FIG. 9 is a rear isometric view of a tool 901 that includes three joined parts in accordance with another embodiment of the invention. The tool 901 can include a fastener engagement portion 110 and a fastener removal portion 120 rigidly joined to a handle member 940 with permanent fasteners 950 . Alternatively, the tool 901 can include pivot pins instead of the permanent fasteners 950 so that the fastener engagement portion 110 and the fastener removal portion 120 can fold over the handle portion 940 for easy storage of the tool.
From the foregoing it will be appreciated that although specific embodiments of the invention may be described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. The teachings provided herein of the present invention may be applied to fastener installation and removal tools in general, and not only to the exemplary roofing tool described above. Accordingly, the invention is not limited by this disclosure, but instead the scope is to be determined entirely by the following claims.
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A tool and method for installing and/or removing fasteners in areas where access is limited. In one embodiment, the tool has a fastener engagement portion toward a first end, a fastener removal portion toward a second end, and an impact surface positioned between the fastener engagement and fastener removal portions. The fastener engagement portion is configured to releasably engage a fastener, and is offset from the impact surface to facilitate positioning a fastener in a confirmed space. The impact surface is configured to remain accessible once the fastener has been properly positioned for installation. A user can strike the impact surface to drive the fastener into a workpiece. The fastener removal portion is configured to engage an installed fastener to extract the installed fastener from the workpiece.
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BACKGROUND OF THE INVENTION
This invention relates in general to polyamide-imide resins and, more specifically, to improved methods for making high molecular weight, flame resistant modified polyamide-imide foams.
Prior U.S. Pat. Nos. 4,161,477, 4,183,838 and 4,183,839 disclosed and claimed certain polyimide compositions and methods of producing adhesive and coating products using those compositions.
The coating and adhesive compositions described in these patents are made by reacting an aromatic tetracarboxylic acid dianhydride with an oxoimine to produce a bisimide, which is then mixed with an inert solvent and a diamine, producing a viscous fluid containing an intimate, unpolymerized mixture of N-substituted cyclic bisimide dicarboxylic acid and diamine which is capable of being converted to a high molecular weight polymer by the application of heat.
When coated on a surface or layered between two surfaces and heated to a temperature in the range of about 177° to 316° C. a tough highly adherent coating or adhesive results. This material was not, however, suitable for use in applications requiring a cellular or foam material, since conventional agitation foaming and addition of known blowing agents add to process costs and complexity and are not entirely effective at the relatively high polymerization temperature required.
A method of producing polyimide foams which overcomes many of these problems is described in our earlier U.S. Pat. Nos. 4,394,464 and 4,426,463. In that method an aromatic dianhydride is reacted with an oxoimine at a temperature of about 190° C. to produce an N-substituted aliphatic imide. The resulting product is cooled below about 70° C. and dissolved in a reactive solvent esterifying agent and heated to reflux for at least 60 minutes to esterify the imide. The material is dried, ground to a powder, then heated to at least 200° C. to cause foaming. An excellent, flexible foam results.
Recently, in our co-pending U.S. patent application Ser. No. 678,992, filed Dec. 6, 1984, now U.S. Pat. No. 4,539,336 we disclosed and claimed another foam producing process which could be varied during processing to produce foams varying from almost entirely polyimide-amide to mixed polyimide and polyimide-amide. An aromatic dianhydride is reacted with an oxoimine in alcohol at 60° to 120° C. followed by adding a diamine, drying to a powder, then heating to melt and foam. The type of polymer and, accordingly, the corresponding physical characteristics depend upon the foaming temperature, in the overall 230° to 315° C. range. While foam physical properties could be easily selected, this process requires high processing temperatures and several complex operations.
While the prior art techniques often produced excellent foams, those methods are undesireably complex, requiring a number of sequential steps to be carefully performed at varying, relatively high temperatures. This tended to result in high energy costs and sometimes varying product quality due to processing variations.
Thus, there is a continuing need for improved methods of producing foams having processing simplicity and low temperature processing, together with superior flexibility and flame resistance.
SUMMARY OF THE INVENTION
The above-noted problems, and others, are overcome by a foam composition made by a method which comprises, basically, the steps of producing an imidocarboxylic acid by reacting a suitable oxoimine with a suitable dianhydride at a temperature of from about 25° to 250° C. in a mole ratio of oxoimine to dianhydride of from about 0.1:1 to 10:1, mixing therewith a suitable organic isocyanate in a mole ratio of isocyanate to imidocarboxylic acid of from about 1.0 to 5.0, in the presence of a suitable quantity of a tertiary amine catalyst and about 0.05 parts by weight water, based on the weight per one part of the imidocarboxylic acid. The mixture spontaneously foams and cures to a flexible, resilient product which is self-extinguishing after exposure to open flame.
The following is exemplary of the reaction which appears to take place between the imidocarboxylic acid and the organic isocyanate to produce the polyamide-imide foam: ##STR1##
In this reaction "R" may be any suitable alkyl, aryl, substituted aryl or substituted alkyl radical. In general, best results are obtained with aryl radicals.
The reaction may be accelerated by heat, typically in the 50° to 100° C. range, and/or the addition of suitable metal salts, typically about 3 parts by weight based on 100 parts by weight of the isocyanate. Surfactants are preferrably added to reduce the surface tension of the rising mass and reduce voids and imperfections. Flame retardant additives may be added, if desired, to further increase the flame resistance of the foam.
DETAILED DESCRIPTION OF THE INVENTION
Any suitable imidocarboxylic acid (a cyclic tetracarboxylic acid containing a functional imido group) may be reacted with the isocyanate to produce the foam of this invention. Typical imidocarboxylic acids include benzophenonetetracarboxyimidocaproic acid monoanhydride, benzenetetracarboxyimidocaproic acid monoanhydride, benzophenonetetracarboxy-bisimidocaproic acid, benzenetetracarboxy-bisimidocaproic acid, oligomers consisting essentially of benzophenonetetracarboxy-bisimidocaproic acid or benzenetetracarboxy-bisimidocaproic acid and mixtures thereof.
While the imidocarboxylic acid may be prepared in any suitable manner, it is preferred that it be prepared by reacting a suitable oxoimine (a cylic lactam) with a suitable aromatic dianhydride in desired proportions. Typical aromatic dianhydrides include those described and referenced in the patents listed above. Due to their ready availability at reasonable prices and the excellent foams which result, pyromettitic dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride, and mixtures thereof are preferred. While any suitable oxoimine may be used, the preferred oxoimines have the following general formula: ##STR2## where "x" is a positive integer from 1 to 7. Of these, best results are obtained with caprolactam. Other preferred oxoimines include 2-piperidone, 2-pyrrolidone and amino acids derived from these three preferred cyclic lactams, namely 6-amino caproic acid, 5-amino valeric acid and 4-amino butyric acid. These preferred oxoimines may be used alone or combined in any suitable mixture. For the purposes of this patent application the term "oxoimine" will be understood to include cyclic lactams as described above and in the three amino acids mentioned in this paragraph.
For best results, the mole ratio of oxoimine to dianhydride should be in the 0.1:1 to 10:1 range. At a ratio of 1:1 a monoimidocarboxylic acid is obtained, while at a ratio of 2:1 a bis-imidocarboxylic acid results. At ratios lower than 1:1 the number of the imido groups in the final monomer is reduced accordingly and at ratios higher than 2:1 a condensation polymerization may occur through extension of the lactam.
The imidocarboxylic acid monomers are reacted with any suitable organic isocyanate to produce the polyamide-imide foam. Typical isocyanates include 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 1,6-hexamethylene diisocyanate and polymeric diisocyanate. Of these, best results are obtained with the polymeric diisocyanate commonly known as PAPI 96, which is, therefore, preferred.
Any suitable proportion of isocyanate to monomer may be used. Good results are obtained with 100 to 500 parts by weight of isocyanate per 100 parts by weight of the imidocarboxylic acid. Best results are obtained at 150 parts.
An appropriate quantity of a suitable tertiary amine catalyst is added to the isocyanate/monomer mixture, together with a suitable quantity of water. Typical tertiary amines include triethyl amine, N-methylmorpholine, diethylethanolamine, ethyl pyridine, methyl ethyl pyridine and mixtures thereof. Best results are obtained with N-methyl morpholine. Any suitable quantity of catalyst may be used. Good results are obtained with about 1.0 to 5.0 parts by weight of catalyst per 100 parts by weight of the diisocyanate with best results at 2.0 parts. Water is added to start the foaming reaction. Good results are obtained with 2.0 to 8.0 parts by weight water, per 100 parts by weight of the imidocarboxylic acid, with best results at 5 parts.
The polymerization/foaming reaction may take place under any suitable conditions. While the reaction will proceed successfully at room temperature, the reaction may be accelerated at slightly elevated temperatures, typically in the range of about 50° to 100° C.
If desired, the reaction may be accelerated by the addition of from about 1.0 to 5.0 weight percent, based on the isocyanate, of a suitable metal salt catalyst. Typical metal salt catalysts include tin oxide, tin acetate, zinc chloride, cobalt acetate, boron fluoride and mixtures thereof. Best results are obtained with about 3 wt % of dibutyl tin diacetate.
Surfactants may be added to improve foam uniformity and reduce voids and other imperfections, if desired. Typical surfactants include Dow Corning 190 or 193 (silicone surfactants), FC430 from Minnesota Mining and Manufacturing Co., Zonyl FSC from E. I. duPont deNemours & Co., L550 from Union Carbide Corp., and BRIJ-78, a polyoxyethylene ether from ICI America. Best results are obtained with silicone surfactants, which are, therefore, preferred. We have found that DC193, a silicone surfactant from Dow Corning, produces optimum results. For best results, from about 1 to 2 wt % of surfactant is used, based on imido carboxylic acid weight.
Flame retardant additives may be added to improve the already high flame resistance of the foams. These include aluminum hydroxide, zinc borate, chlorinated compounds, phosphates such as tricresyl phosphate and chloroaryl phosphate, borates, fully cured polyimide powders and mixtures thereof. In general, about 10 to 50 wt %, based on total weight is effective.
Other additives, such as ultraviolet absorbers, reinforcing fibers, fillers, etc., may be added in any suitable quantity prior to adding the organic catalyst and water.
Details of the invention will be further understood upon reference to the following examples, which describe preferred embodiments of the methods and compositions of this invention. All parts and percentages are by weight unless otherwise indicated.
EXAMPLE I
About 322.23 g, 1M, of 3,3', 4,4'-benzophenonetetracarboxylic acid dianhydride and about 113.6 g, 1M, of caprolactam are charged into a two liter flask and heated to about 190° C. for about 0.5 to 5 hours. The reaction mixture is transferred, while hot, into an open dish and allowed to cool to room temperature. The solid product is crushed, pulverized and screened through a U.S. mesh screen, #50. The product obtained is essentially benzophenonbetetracarboxyimido monoanhydride. About 30 g of the product and about 1.9 g, of diethylethanolamine and about 51.0 g, of PAPI 94, a polymeric diisocyanate which is a product of the Upjohn Corp. and about 16.0 g water are added to the mixture, which is stirred well. The mixture spontaneously foams. After about 30 minutes the foam cures to a dry, flexible foam which is self extinguishing after exposure to open flame.
EXAMPLE II
About 226.3 g, 2M, of caprolactam is reacted with 1M, about 322.2 g, of 3,3', 4,4'-benzophenonetetracarboxylic acid dianhydride in a two liter flask, with the reactants heated to about 210° C. The product is a solid consisting of benzophenonetetracarboxy bis-imidocaproic acid. About 18.2 g of this product is mixed in a beaker with about 4.5 g of DC 193 silicone surfactant from Dow Corning and about 3 g of N-methylmorpholine and stirred for about 8 minutes. To the mixture is added about 19.6 g of a polymeric isocyanate available from Upjohn under the PAPI 94 designation. About 1.3 g of water is stirred into the mixture. The mixture spontaneously foams, producing a flexible, flame resistant foam product.
EXAMPLE III
The procedure of Example II is repeated, except that the anhydride is benzene tetracarboxylic acid dianhydride. An excellent, flexible foam results.
EXAMPLE IV
The procedure of Example II is repeated with additional samples, with the following oxoimines substituted for the caprolactam: IV(a) 2M of 2-piperidone, IV(b) 2M of 2-pyrrolidone, IV(c) 2M of 6-amino caproic acid, and IV(d) 2M of 4-amino butyric acid. In each case an excellent foam results.
EXAMPLE V
The procedure of Example II is repeated, except that in place of the 19.6 g of PAPI 94 polymeric isocyanate, the following organic isocyanates are used: V(a) 19.6 g of 4,4'-diphenylmethane diisocyanate, and V(b) 14 g of 2,4-toluene diisocyanate. In each case, an excellent flame resistant foam results.
EXAMPLE VI
The procedure of Example I is repeated, except that in place of the diethylethanolamine, the following tertiary amines are used: VI(a) 1.9 g of triethyl amine, VI(b) 1.9 g of N-methylmorpholine, VI(c) 1.9 g of ethyl pyridine, and VI(d) a mixture of 10 g diethylethanolamine and 10 g of methyl ethyl pyridine. Foams of excellent properties result.
EXAMPLE VII
The procedure of Example II is repeated, except that the quantity of water is varied as follows: VII(a) no water, VII(b) 0.3 g water, VII(c) 1.0 g water, VII(d) 2.5 g water, VII(e) 5 g water and VII(f) 10 g water. With no water, no foam results. In the other sub-examples, best results are obtained with 2.5 g of the water. With the very large quantities of water, the foam is impregnated with excess water.
EXAMPLE VIII
The procedure according to Example I is repeated with the exception that the temperature of the reaction between the imidocarboxylic acid and the isocyanate is varied as follows: VIII(a) 20° C., VIII(b) 50°, VIII(c) 100° C., VIII(d) 250° C. Best results are obtained with 50° C. conditions. Lower temperatures result in good foam, while higher temperatures result in foam collapse.
EXAMPLE IX
The procedures of Example II are repeated, with the addition of the following metal salts as catalysts added just before the addition of water: IX(a) 0.8 g tin oxide, IX(b) 0.8 g of dibutyl tin diacetate, IX(c) 0.8 zinc chloride, IX(d) a mixture of 0.4 g cobalt acetate and 0.4 g boron fluoride. In all cases a foam is obtained but IX(b) produced a foam with very little unreacted skin.
EXAMPLE X
The procedures of Example I are repeated except that the following additives are added just before addition of the water: X(a) 20 g aluminum hydroxide, X(b) 20 g tricresylphosphate, X(c) a mixture of 10 g zinc borate and 10 g triphenyl phosphate, X(d) 20 g of finely divided, fully cured polyimide powder prepared as described in U.S. Pat. No. 4,161,477, X(e) 20 g finely divided glass fibers, and X(f) 20 g chopped graphite fibers. The foams produced in sub-examples X(a) through X(d) are found to have superior flame resistance while those of sub-examples X(e) and X(f) are found to have increased compressive strength.
EXAMPLE XI
The procedures of Example I are repeated, with the foamable material being shaped as follows immediately after the water is added: XI(a) the foam is placed in a conventional vented box-like mold, resulting in a rectangular foam block or bun, XI(b) the foam is extruded from a conventional extrusion device as it foams to produce rod-like foam structures, and XI(c) the material is spread on a moving belt as it foams, resulting in a long foam sheet.
Although specific components, proportions and conditions have been specified in the above examples, these may be varied with similar results. In addition, other materials may be added to the foamable material, such as fillers, colorants, ultraviolet absorbers or the like.
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Methods of producing high molecular weight polyamide-imide foams having superior flame resistance and the foam products produced thereby. Initially, an imidocarboxylic acid is prepared by reacting a suitable oxoimine with a suitable cyclic dianhydride at a temperature of from about 25° to 250° C. in the presence of a solvent or by melt condensation without a solvent. The ratio of oxoimine to dianhydride may be varied to vary the number of imido groups in the final monomer. The imidocarboxylic acid monomer is reacted with an organic isocyanate in the presence of a suitable tertiary diamine catalyst and water to produce the polyamide-imide foam. The material foams spontaneously at room temperature. The reaction may be accelerated by heat or the addition of suitable metal salts. Additives, such as surfactants, flame retardants, fillers, etc., may be added if desired.
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FIELD OF THE INVENTION
The present invention is in the field of minimizing battery corrosive electrolyte leakage from devices that use batteries, including alkaline and rechargeable batteries, and is especially concerned with minimizing battery corrosive electrolyte leakage in portable, hand-held devices, one example of which is a flashlight, which use batteries held in a battery compartment in an in series arrangement.
BACKGROUND OF THE INVENTION
Batteries of all sizes and types, including chargeable and non-rechargeable, are used in a variety of devices to provide power to electrical circuits.
Alkaline batteries have provided power to consumer and hand-held devices, one example of which is a flashlight, for decades. A general description of the construction of alkaline batteries is described in the prior art, an example of which is the article found at http://www.electrical4u.com/alkaline-batteries, as well as a technical bulletin about Duracell® batteries found at http://ww2.duracell.com/en-US/Global-Technical-Content-Library/Technical-Bulletins.ispx, both of which are incorporated by reference herein, from which FIG. 1 and the following description of such construction is obtained. The body of a battery, generally designated as 100 , is made of a hollow steel can 102 comprised of an outer cylindrical wall 1020 C, a top surface 102 TC and a bottom surface 102 BC. Can 102 contains all materials of the battery. A positive cap with a nipple 103 of battery 100 is projected from the top of can 102 . A manganese dioxide cathode powder mix 104 is pressed against the inner steel wall of can 102 so that the steel case of the can becomes the cathode current collector and serves as the positive terminal of the cell. The inner surface of the thick layer of cathode mixture is covered with a porous separator 105 which isolates the electrodes of the battery. The central space, inside separator 105 , is filled by a zinc anode powder 106 . The porous nature of the anode, cathode, and separator materials allows them to be thoroughly saturated with the alkaline electrolyte solution. A metallic pin 107 is welded to the external anode cap 111 and extends through a plastic cap or grommet 109 into the center of the anode powder mix maintaining intimate contact. This pin is called a negative collector pin or an anode current collector. Plastic cap or grommet 109 is sealed to the steel can 102 by means of radial crimping pressure and a sealant. Anode cap 111 is electrically isolated from the positive cell case 102 with an insulator 110 . A vent mechanism 112 is incorporated into the plastic grommet 109 to protect against cell rupture. An outer insulative wrapping 102 W is also commonly applied to can 102 which is also used to contain printed material, such as trademarks and trade dress of the battery manufacturer.
Batteries, including alkaline batteries, are often aligned in series, in which a positive terminal of one battery is in direct contact with a negative terminal of another battery. Using a flashlight as an example, it is well known in the prior art to include a battery compartment, such as a barrel, in which batteries (such as AAA, AA, C or D cell size) are aligned in series. While such an arrangement is the common and traditional arrangement, there have been prior suggestions that steps be taken to protect battery electrodes in a series arrangement where two batteries connect with each other, such as through the use of a battery spacer and resilient conductor as taught in U.S. Pat. Nos. 5,645,955 and 5,795,675.
However, despite the fact that batteries, including alkaline batteries, have been used in a variety of devices for decades, there has been a well-known problem that batteries can leak battery corrosive electrolyte over time, causing problems related to cleaning such leaks and sometimes ruining a device in which the leak occurs.
Accordingly, the present invention addresses a long-felt need for a way to minimize battery corrosive electrolyte leaks in devices that use batteries, including but not limited to, flashlights.
SUMMARY OF THE INVENTION
The present invention is generally directed to reducing battery corrosive electrolyte leak by absorbing forces generated during impact of a device holding the batteries and preventing such forces from being transferred to terminal contacts of batteries held in a series configuration. Contacts of batteries connected in series are protected by use of shock absorbing spacers while electrical contact is maintained by resilient contacts (which can be integrally held by the shock absorbing spacers) and a terminal end shock absorber is positioned so that the terminal end will be cushioned by the terminal end shock absorber when a force is applied to the series configuration causing the batteries to move relative to the terminal battery holder.
When the device in which batteries are being used is a flashlight, a two-piece tail cap can be used, an inner member of which is driven by an outer member, and tail caps of existing flashlights can be replaced so that a strong tall cap spring no longer provides a biasing means against the terminal contact of the terminal battery.
Accordingly, it is a primary object of the present invention to minimize battery corrosive electrolyte leakage in devices in which batteries are held in a series configuration.
This and further objects and advantages will be apparent to those skilled in the art in connection with the drawings and the detailed description of the invention set forth below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a cutaway view of a Duracell® cylindrical alkaline battery which constitutes prior art.
FIG. 2 is a top view illustrating a first design of a shock absorbing spacer assembly in accordance with the present invention, FIG. 3 is a cross sectional view of FIG. 2 , FIG. 5 is a side view of FIG. 2 and FIG. 4 illustrates a resilient contact used in the assembly of FIG. 2 .
FIG. 6 is a top view illustrating a second design of a shock absorbing spacer assembly in accordance with the present invention, FIG. 7 is a cross sectional view of FIG. 6 , FIG. 9 is a side view of FIG. 6 and FIG. 8 illustrates a resilient contact used in the assembly of FIG. 6 .
FIG. 10 is a top view illustrating a third design of a shock absorbing spacer assembly in accordance with the present invention, FIG. 11 is a cross sectional view of FIG. 10 , FIG. 13 is a side view of FIG. 10 and FIG. 12 illustrates a resilient contact used in the assembly of FIG. 10 .
FIG. 14 is a top view illustrating a fourth design of a shock absorbing spacer assembly in accordance with the present invention, FIG. 15 is a cross sectional view of FIG. 14 , FIG. 17 is a side view of FIG. 14 and FIG. 16 illustrates a resilient contact used in the assembly of FIG. 14 .
FIGS. 18, 20 and 22 each illustrate a spring design that can be used in a shock absorbing spacer assembly in accordance with the present invention as illustrated in FIGS. 19, 21 and 23 , respectively.
FIG. 24 illustrates a flashlight with the shock absorbing spacer of FIG. 2 being used in a flashlight while FIG. 25 is a close up view of a portion of FIG. 24 .
FIG. 26 illustrates an outer member of a tail cap that receives an inner member of a tail cap illustrated in FIG. 29 in accordance with the present invention.
FIG. 27 is an end view of the outer member of FIG. 26 while FIG. 28 is a cross sectional view of FIG. 27 .
FIG. 30 is an end view of the inner member of FIG. 29 while FIG. 31 is a cross sectional view of FIG. 30 and FIG. 32 is an end view looking at the back side of FIG. 31 .
FIG. 33 illustrates the inner member of FIG. 29 screwed into the threads of a flashlight barrel with the male and female splines of inner and outer tail cap members of FIGS. 26 and 29 engaged while FIG. 34 shows the outer tail cap member of FIG. 33 screwed into the inner tail cap member.
FIG. 35 is an assembled two piece tail cap, illustrated in FIGS. 26 and 29 , except that a shock absorbing material 202 has been added to the inner member while FIG. 36 is an exploded view of the assembly of FIG. 35 and FIGS. 37 and 38 are identical to FIGS. 33 and 34 except for the addition of shock absorbing material 202 .
FIG. 39 illustrates a replacement tail cap with a terminal end shock absorber in accordance with the present invention while FIG. 40 is an exploded view of FIG. 39 .
FIG. 41 illustrates a second replacement tail cap with a terminal end shock absorber in accordance with the present invention while FIG. 42 is an exploded view of FIG. 41 .
DETAILED DESCRIPTION OF THE INVENTION
In the Figures and the following detailed description, numerals indicate various physical components, elements or assemblies, with like numerals referring to like features throughout both the drawings and the description. Although the Figures are described in greater detail below, the following is a glossary of elements identified in the Figures.
1 flashlight 2 shock absorbing spacer 11 barrel of flashlight 1 11 T thread of barrel 11 12 head of flashlight 1 13 light source of flashlight 1 14 tail cap of flashlight 1 20 shock absorbing spacer assembly 22 resilient contact 22 H hole in resilient contact 22 22 GH guide hole in resilient contact 22 31 curling arm of resilient contact 22 32 ear of resilient contact 22 40 spring 41 lock ring 42 lip seal 51 outer member of tail cap 52 thread of member 51 53 knurl 54 F female spline 55 spring contact 57 central bore 61 inner member of tail cap 62 thread of member 61 64 M male spline 65 battery can engaging surface 100 battery 100 ( 1 ) first of two batteries in a series configuration 100 ( 2 ) second of two batteries in a series configuration 102 can 1026 C bottom surface of can 102 1020 C outer cylindrical wall of can 102 102 TC top surface of can 102 102 W battery wrap 103 positive cap with nipple 104 cathode powder 105 porous separator 106 anode powder 107 negative collector pin or anode current collector 109 plastic cap or grommet 110 electrical insulator 111 anode cap 112 vent mechanism 202 shock absorbing material 301 modified shock absorbing spacer 302 spring 303 tail cap
Generally speaking, when two or more cylindrical batteries are held in a series configuration in a battery compartment, a top surface of each of the batteries has a nipple contact while the bottom surface of each of the batteries has a generally flat surface, and the top nipple contact is traditionally a positive or cathode contact while the bottom flat contact is traditionally a negative or anode contact. The battery compartment which holds the batteries in a series configuration traditionally has a top contact against which a first battery in the series is loaded and a compression spring that serves both as an electrical contact for the last battery in the series (hereinafter the terminal battery) and as a biasing means so as to keep the batteries in series held in electrical contact by biasing the bottom flat contact of the terminal battery toward the top contact.
While the present invention is not limited to use with flashlights, and is applicable to any device with a battery compartment in which two or more batteries are held in a series configuration, the present invention will hereinafter be described and illustrated, for ease of understanding, by reference to only one specific device—a flashlight, examples of which are described in U.S. Pat. Nos. 6,361,183 and 8,366,290, the disclosures of which are specifically incorporated by reference herein.
In a flashlight 1 the terminal battery is the last battery which is inserted into barrel 11 of the flashlight and the terminal battery is biased toward head 12 of the flashlight, which contains light source 12 , by a compression spring included in a tail cap 14 which seals off the barrel after the batteries have been inserted and the tail cap is screwed on and into place.
While it is traditionally the case that the bottom flat contact of a first battery in a series configuration (which is inserted into a flashlight barrel before the next or second battery in a series configuration) is in both physical and electrical contact with a top nipple contact of the second battery in the series configuration, in accordance with one aspect of the present invention, such physical contact is prevented by a shock absorbing spacer inserted between the first and the second batteries in the series configuration.
In an especially preferred embodiment of the present invention, a shock absorbing spacer 2 is configured as a disc which has a circular outer cross section which is of substantially the same diameter as the diameter of the two cylindrical batteries it is inserted between and an inner cross section which is of substantially the same diameter as that of the bottom surface 102 BC of the first battery and/or the top surface 102 TC of the second battery. It is especially preferred that shock absorbing spacer 2 have a thickness sufficient so as to keep the top nipple contact of the second battery in the series configuration from coming into contact with the bottom flat contact of the first battery in the series configuration, even when the flashlight is subjected to extreme shock, such as, for example, being dropped from a distance of several meters, or more. Accordingly, the thickness of the shock absorbing spacer should be greater than the height of the nipple of the top nipple contact, and take into account variations in such height in various batteries, as well as any compression of the shock absorbing spacer when it is performing its shock absorbing function under anticipated or desired performance criteria. The shock absorbing spacer can be made of any material that absorbs shock, such as energy-absorbing plastic or rubber, and it is especially preferred that the material be a cushioning material that absorbs a proportion of the kinetic energy arising when the flashlight suffers impact or is dropped, while still having sufficient recovery that the shock absorbing spacer will continue to function over time.
Because shock absorbing spacer 2 keeps the top nipple contact of the second battery in the series configuration 100 ( 2 ) from coming into contact with the bottom flat contact of the first battery in the series configuration 100 ( 1 ), the two terminals must be electrically connected, and, in an especially preferred embodiment of the present invention, this is done by at least one resilient contact held by the shock absorbing spacer in a shock absorbing spacer assembly 20 , and the electrical contact with the top nipple contact is made with the base below the nipple, or outer diameter of the nipple (less preferably), but not the top surface of the nipple, as illustrated in FIG. 25 in which shock absorbing spacer 2 has a thickness of Y whereas the distance between the top nipple contact of the second battery 100 ( 2 ) and the bottom flat contact of the first battery 100 ( 1 ) is X. The reason it is especially preferred that the at least one resilient contact not contact the top of the nipple is that reliance on such contact would mean that shock absorbing spacer 2 would need to be thicker so that a shock would not allow energy to be passed from the nipple through the resilient contact to the bottom flat contact.
The at least one resilient contact can take on many different forms, some preferred embodiments of which are illustrated in FIGS. 4, 8, 12, 16, 18, 20 and 22 .
In FIG. 4 , resilient contact 22 is formed from stamped metal with a plurality of holes 22 H, two guide holes 22 GH, and a curling arm 31 . Two mirror imaged contacts 22 are mounted opposite of each other (see FIG. 3 ), with their holes 22 H and guide holes 22 GH aligned, and then shock absorbing spacer 2 is molded so that its material fills holes 22 H but leaves guide holes 22 GH unfilled, for later use in assembly, to form shock absorbing spacer assembly 20 .
In FIGS. 8, 12 and 16 , a single resilient contact 22 is formed from stamped metal, but multiple ears 32 are bent in opposing directions as illustrated in FIGS. 7, 11 and 15 , respectively, and the ears of the different embodiments have different configurations. A shock absorbing spacer 2 is molded around the single resilient contacts 22 to form the different embodiments of shock absorbing spacer assembly 20 illustrated in FIGS. 6, 10 and 14 .
In additional embodiments, resilient contact 22 can be a spring, examples of shapes of which are illustrated in FIGS. 18, 20 and 22 , and such springs can be secured within shock absorbing spacer 2 by molding to form shock absorbing spacer assemblies as illustrated in FIGS. 19, 21 and 23 , respectively.
Shock absorbing spacer assemblies 20 can easily be dropped in between batteries as batteries are being loaded into a barrel 11 of a flashlight 1 ; one shock absorbing spacer assembly should be inserted between every two batteries; accordingly, a flashlight having two batteries in series will use one shock absorbing spacer assembly between the two batteries; a flashlight having three batteries in series will use two shock absorbing spacer assemblies between the first and second, and the second and third batteries; a flashlight having four batteries in series will use three shock absorbing spacer assemblies between the first and second, the second and third, and the third and fourth batteries, and so on, so that the number of shock absorbing spacer assemblies used in a barrel will equal one less than the number of batteries arranged in a series configuration. In view of the ease of such assembly, it is easy to see why it is especially preferred that shock absorbing spacer 2 and resilient contact 22 form a single assembly; however, resilient contact 22 could also be detached from shock absorbing spacer to accomplish the same functional purpose, albeit with the need for a more difficult assembly process.
Use of shock absorbing spacer assemblies 20 between two batteries in a series arrangement allows energy imparted during a shock to be absorbed by the shock absorbing spacer assemblies and also imparts substantially all of the shock between bottom surface 102 BC of can 102 of the first battery and top surface 102 TC of can 102 of the second battery in a series arrangement, rather than imparting shock to either bottom flat contact 111 of the first battery or top nipple contact 103 of the second battery.
In another aspect of the present invention, a terminal end shock absorber is positioned so that the terminal end of a terminal battery in a series configuration will be cushioned by the terminal end shock absorber when a force is applied to the series configuration causing the two or more cylindrical batteries to move toward a terminal retaining member (which is a tail cap 15 in flashlight 1 ).
In some situations, it may be possible to use a shock absorbing spacer 20 as a terminal shock absorber, depending upon how electrical contact is made with a tail cap, how the tail cap fits into a closed electrical circuit, and how much space there is between bottom flat contact 111 of the terminal battery and its contact point within the tail cap. In an especially preferred embodiment of the present invention, a specially designed tail cap assembly is used to provide a terminal end shock absorber.
Because many different devices make contact with the terminal end of a terminal battery in different ways, even in one device category, such as a flashlight, it is worth noting that sometimes a strong spring is used to make such contact; however, if one is designing a particular device, especially where cylindrical batteries are inserted into a cylindrical tube, one way to minimize the amount of stress that might be applied to the terminal end of the terminal battery is to insure a snug fit so there is less room for the batteries to move in the event of extreme shock.
One of the reasons why batteries may not enjoy a snug fit is variations in tolerance and production specifications/actual manufactured dimensions of batteries. As more batteries are aligned in a series configuration, there is a greater possibility of cumulative variations. In accordance with one aspect of the present invention, a snug fit is created by the combination of eliminating variations between pairs of batteries with a spacer (which can either be a shock absorbing spacer, as already disclosed, or a non-shock absorbing spacer having the same construction except for the use of a non-shock absorbing material) and then insuring a snug fit by creating a snug mechanical fit at the bottom surface of the can of the terminal battery. Use of spacers between adjoining battery terminals helps cancel variations in dimensions of the batteries because variations in positive cap 103 or anode cap 111 are no longer important since the spacer is held between bottom surface 102 BS of the first battery and top surface 102 TC of the second battery, and the width of the spacer is greater than the nipple of positive cap 103 . Accordingly, when a snug fit is created at bottom surface 1028 of the terminal battery, that snug fit will ensure that the cans of the batteries in the series configuration, with spacers between each pair of batteries, create a solid continuous length of material in which no meaningful force is applied to the battery terminals between two adjoining batteries while the terminal end of the terminal battery is retained at its can, rather than at its anode cap.
One especially preferred embodiment of a device which creates a snug fit for the terminal end of a terminal battery is a mechanical contact that can be tightened against the bottom surface 102 of the terminal battery until a snug fit is obtained, and one example of such a device is disclosed in FIGS. 26-32 , which is especially useful for the device category of a flashlight, in which a two piece tail cap is provided in which an inner member 61 of the tail cap 50 can be driven by an outer member 51 of tail cap 50 to screw into flashlight barrel threads 11 T so that bottom surface 102 BC of the terminal battery is held snugly by battery can engaging surface 65 of inner member 61 as illustrated in FIG. 33 . In this especially preferred embodiment, mating splines are used to illustrate one mechanical driving mechanism; however, this embodiment is meant to be illustrative, rather than limiting, and any other suitable driving mechanism could also be used in alternative embodiments within the scope of the present invention. Returning to FIG. 33 , inner member 61 is driven by engaging female splines 54 F in outer member 51 of tail cap 50 with male splines 64 M of inner member 61 and then using outer member 51 to screw inner member 61 into position; once inner member 61 is fully screwed into position, female splines 54 F and 64 M are disengaged and threads 52 of outer member 51 are then screwed into flashlight barrel threads 11 T to secure outer member 51 to barrel 11 as illustrated in FIG. 34 . It is especially useful if a lock ring 41 is used to secure outer member 51 (which has a lip seal 42 ) to inner member 61 (see FIGS. 33 and 34 ); inner member 61 and lock ring 41 can be designed so that lock ring 41 will not be removable once it is in place or so that it can be removable with a certain amount of force. Because the two piece construction of tail cap 50 allows battery can engaging surface 65 to snugly hold bottom surface 102 BC of the terminal battery (and it is especially preferred that battery can engaging surface 65 engage all or substantially all of bottom surface 102 BC, but not anode cap 111 ), an electrically conductive spring 40 may or may not be required, depending upon whether bottom surface 102 BC is insulated, such as by a battery wrap 102 W; but, even if it is required, conductive spring 40 need not be a strongly compressed spring and can have a minimum contact force (of around 200 grams or 0.44 lbs.)—just enough to ensure electrical contact, but not so much that it will provide a mechanism for imparting a damaging force to the terminal end of the terminal battery in the event of extreme shock. (Springs used in tail caps of prior art flashlights to create a biasing means forcing the batteries toward the top contact could have a much higher contact force, on the order of 10 lbs. or more.) Spring 40 , as illustrated in FIG. 33 , can be secured by spring contact 55 .
One way of minimizing any potential damaging force that spring 40 might impart to the terminal end of the terminal battery in the event of extreme shock is to minimize its length and strength. FIGS. 35-41 illustrate an alternative embodiment of a two piece tail cap in which a central bore 57 in which spring 40 is held is minimized so that a shorter spring can be used for ensuring electrical contact between the terminal end of the terminal battery and the tail cap.
The two piece tail cap construction described so far can also be used in devices that utilize rechargeable battery packs, an example of which is a NiMH battery for the Mag Charger® LED flashlight. In such a device, multiple rechargeable batteries are wrapped together in a snug casing, which is electrically insulating, so the terminal end of the terminal battery extends out of the casing, and a button end of a first battery also extends out of the casing, but the other ends of the batteries held in series are held tightly together inside of the battery wrap. In such a device, while shock absorbing spacers 2 might be used inside of the casing when the battery pack is manufactured, it is not possible to use shock absorbing spacers 2 with existing battery packs without destroying the battery wrap, which is not desirable; however, the two piece tail cap construction already described will still prove useful with such battery packs.
The two piece tail cap construction already described can also be modified to provide a shock absorbing spacer 202 that makes contact with bottom surface 102 BC of the terminal battery, and FIGS. 35-38 illustrate one example of how such a shock absorbing spacer can be provided. In this especially preferred embodiment, shock absorbing spacer 202 is held or mounted to inner member 61 of tail cap 50 , shock absorbing spacer 202 is configured to absorb a primary impact force imparted between it and bottom surface 102 BC of can 102 , and shock absorbing material 202 may be similar or identical to that used in shock absorbing spacer 2 . Such construction is also especially preferred for use with rechargeable battery packs that do not utilize shock absorbing spacers between batteries contained with the battery packs.
Because there are millions of flashlights already in use, it is also desirable to provide a kit and method by which such existing flashlights can benefit from the teachings of the present invention.
As already noted, flashlights in use today typically have a compression spring that serves both as an electrical contact for the terminal battery and as a biasing means so as to keep the batteries in series held in electrical contact by biasing the bottom flat contact of the terminal battery toward the top contact. This means that the compression spring is usually fairly strong, and it exerts a strong compressive force against bottom flat contact 111 of the terminal battery (not just to maintain electrical contact, but also to keep the batteries biased toward the top contact); however, when the battery receives a shock, movement of the batteries against the strong compression spring causes the spring to further compress, applying even greater compression force against bottom flat contact 111 . By contrast, the present invention seeks to minimize the compressive force applied against bottom flat contact 111 of the terminal battery and to rely upon a terminal end shock absorber to both absorb some shock as well as transfer energy through bottom surface 102 BC of can 102 of the terminal battery, rather than through bottom flat contact 111 .
One way a flashlight can be retrofitted with a terminal end shock absorber in accordance with the present invention is to replace an existing tail cap assembly with its compression spring with a new tail cap assembly 200 such as is illustrated in FIGS. 39 and 40 . Replacement tail cap assembly 200 utilizes a shock absorbing material 202 , a tail cap resilient contact 201 and a tail cap 203 . Shock absorbing material 202 is configured to absorb a primary impact force imparted between it and bottom surface 102 BC of can 102 of the terminal battery while the tail cap resilient contact is configured to absorb a secondary impact force imparted between it and the flat contact of the terminal battery, wherein the secondary impact force is substantially less than the primary impact force. While tail cap resilient contact 201 might be configured similarly to resilient contact 22 , it may also be configured as a small compression spring, which may be more suitable for use in a replacement kit in which all of the components of the flashlight have not been designed so as to take advantage of use of one or more shock absorbing spacer assemblies and a terminal end shock absorber. Shock absorbing material 202 may be similar or identical to that used in shock absorbing spacer 2 .
An alternative embodiment to that shown in FIGS. 39 and 40 is to utilize a shock absorbing spacer 2 , as already disclosed, which is modified as illustrated in FIGS. 41 and 42 . In this embodiment, the contacts with the terminal end of the terminal battery (or the terminal end of a rechargeable battery pack) of modified spacer 301 remain the same as already described, but the other contacts are replaced with a spring 302 which makes electrical contact with tail cap 303 .
While the invention has been described herein with reference to certain preferred embodiments, those embodiments have been presented by way of example only, and not to limit the scope of the invention. Additional embodiments will be obvious to those skilled in the art having the benefit of this detailed description. For example, because the terminal end shock absorber does not need to separate two terminals of batteries in series, but a terminal end of a terminal battery from a tail cap, the terminal end shock absorber might be constructed to provide shock absorption through mechanical means, or means other than using a shock absorbing material similar to that of shock absorbing spacer 2 ; thus, for example, a tail cap might be designed to include one or more mechanical pistons that compress air within one or more enclosed spaces with appropriate pressure relief.
Accordingly, still further changes and modifications in the actual concepts descried herein can readily be made without departing from the spirit and scope of the disclosed inventions as defined by the following claims.
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Battery corrosive electrolyte leakage is reduced by absorbing forces generated during impact of a device holding the batteries and preventing such forces from being transferred to terminal contacts of batteries held in a series configuration. Contacts of batteries connected in series are protected by use of shock absorbing spacers while a terminal end shock absorber is positioned so that the terminal end will be cushioned when a force is applied to the series configuration causing the batteries to move relative to the terminal battery.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a divisional of, and claims priority under 35 USC 120 to, U.S. application Ser. No. 13/105,611, filed May 11, 2011, which claims benefit under 35 U.S.C. §119 of German patent application serial number 10 2010 028 942.6, filed May 12, 2010. The contents of both of these applications are hereby incorporated by reference in its entirety.
FIELD
The disclosure relates to a method for producing a support structure, in which a component can be held by friction. The disclosure furthermore relates to a method for connecting a component to the support structure, and to an assembly including a support structure and at least one held component.
As used herein, connecting two components refers to mechanical joining of the components. Here, according to the application, a first component has a cut-out, in which a second component can be held for the purposes of a connection. In the context of the application, the first component is referred to as a support structure.
BACKGROUND
It is well-known that a component can be held in a support structure by substance-to-substance connection, form fit and/or force fit. Substance-to-substance connection solutions can be disadvantageous because they may not be able to be released again. Components connected by substance-to-substance connection can generally only be separated from one another again by destroying at least one component. A connection by screws or the like is impracticable or imposes burdensome technical features in some cases where a plurality of components should be held by a support structure in a limited installation space and/or if positioning with very low tolerances is desired, for example in optical systems.
It is also known to connect a component to a support structure by press joining. In the process, it is known to press in the component by an axial force or to connect the components by shrinking, i.e. by deforming the support structure and/or the component due to heating or cooling. In the case of shrinking, a cut-out in the support structure for the component to be held and the component are produced for an interference fit. It is possible to join the component into the cut-out by heating the cut-out, which is connected to an expansion of the latter, and/or by cooling the component to be held, which is connected to a contraction of the latter. After the components are returned to normal temperature, the components are interconnected by an interference fit. As a result of a good thermal contact between the interconnected components, it is no longer possible, in general, to set a temperature difference. Therefore, the connection can, in general, no longer be released.
SUMMARY
The disclosure provides a method for producing a support structure, a method for connecting at least one component to a support structure, and an assembly including a support structure and at least one component, which allow a multiplicity of components to be held in a support structure by via a releasable connection.
According to one aspect of the disclosure, a method is provided for producing a support structure including an at least partly reversibly deformable base body with at least one cut-out. A component can be held in the cut-out by force-fit. The method includes applying a deformation force to the base body of the support structure such that the base body is reversibly deformed into a braced state. The method also includes machining the base body in the braced state. At least one opening is formed into the base body and/or widened. The opening is deformed when the deformation force is removed such that the at least one cut-out is formed. The at least one opening is formed such that by applying a joining force to the base body of the support structure the at least one cut-out is deformable into a deformed cut-out. A component to be held is receivable in the deformed cut-out with a clearance fit so that, when reducing or removing the joining force, a pressure contact between a held component and the cut-out in a predefined circumferential region is feasible by an at least partial recovery of the deformed cut-out.
As a result, this establishes a support structure, in which components can be held with high precision while involving little installation space.
In the context of the disclosure, the term deformation force is used, even if differently directed forces are applied to the base body at different points of contact. The deformation force deforms or shapes the base body. The base body is reversibly deformable. In the context of the application, a reversible deformation or a reversible shaping refers to a deformation or a shaping as a result of an active force, wherein the body, after the active force responsible for the deformation or the shaping has been removed, has the urge to return to its original shape. Provided that components were introduced into the deformed cut-outs in the braced state, a return to the original shape is prevented at least in part. As a result of the restoration forces acting on the base body, the held component is held in a clamped fashion. After the partial recovery, the cut-out and the component form an interference fit.
In the context of the disclosure, a clearance fit refers to a connection of a component to a cut-out in a support structure in which the component is held in the cut-out with play. In the context of the disclosure, an interference fit refers to a connection of a component to a cut-out in a support structure in which the component is taken up and held in the cut-out in a clamping fashion, wherein forces may be transferred over the connection.
In advantageous embodiments, a joining force applied to assemble the components to be held by the cut-outs corresponds in terms of magnitude and direction to a deformation force applied to produce the support structure.
In terms of shape and/or size, the cut-outs are matched to the components to be held such that in the case of an at least partial recovery of the cut-out there is a pressure contact between a held component and the cut-out in predefined circumferential regions. In advantageous embodiments, pressure contact is provided in at least three circumferential regions for there to be a stable clamping of a held component.
In some embodiments, the cut-outs are formed and/or reworked by chemical substances, laser cutting, boring and/or milling and/or steps for fine machining such as reaming, turning, honing and lapping. Here, in one embodiment of the disclosure, bores are introduced into the braced base body for introducing the cut-outs. In one embodiment, a position for the bore is already drawn in and/or centre-punched or stored in the machining program of the machining tool in the undeformed state of the base body.
A deformation profile of the cut-outs after the deformation force has been removed or reduced and the resulting contact faces between the support structure and the inserted components depends on, among other things, the shape of the cut-outs, the arrangement of the cut-outs on the support structure and on the direction and magnitude of the deformation force.
The cut-out in the braced state and the associated component have mutually complementary cross-sectional shapes in advantageous embodiments. Different, but mutually matched shapes are provided in other embodiments. In one embodiment, the cut-out and the component designed in a complementary fashion thereto each have a polygonal profile. Frictional and interlocking clamping of the component is realized in such an embodiment. Hereby, the protection against slipping through, i.e. a misalignment as a result of torques acting on the component, is increased in these embodiments. This is particularly advantageous if torques are to transmitted between the support structure and the component.
In advantageous embodiments, the at least one opening is formed such that it has a circular cross section, wherein a diameter of the at least one opening is chosen larger than an outer circle diameter of the component to be held. In the process, the opening can be produced in a simple and cost-effective fashion by standard machining tools, such as, for example, drilling tools, reamers or honing tools. The outer circle diameter of a component is defined as the diameter of the circle inscribing the outer contour of the component. An associated component can have a circular-cylindrical shape in at least one contact region. Here, the region that is held by the cut-out is referred to as the contact region. In this case the outer circle diameter is the diameter of the circular-cylindrical contact region. Here, the cut-out, which is braced in the joining state, and the component form a bore/shaft fit. Bores and components with circular-cylindrical contact regions can be produced in a simple and cost-effective fashion. It is also possible to align the component in the cut-out by rotation.
In advantageous embodiments, the at least one opening is preformed before the deformation force is applied to the base body. The desired lateral position of the components to be held can easily be set in a precise fashion in the undeformed state. Thereby, it is also possible to implement lateral positionings with a positioning error of less than or equal to 20 μm. In the process, performing, in particular pilot boring in the unbraced state is brought about such that there is still a sufficient allowance for fine-machining of the cut-out in the braced state.
In an advantageous embodiment, a pilot boring having a circular cross section with a diameter is formed, wherein the diameter of the pilot boring is chosen such that by applying the deformation force to the base body of the support structure the pilot boring is deformed into a deformed pilot boring having an outer circle diameter that is smaller than the outer circle diameter of the component to be held. The outer circle diameter of the deformed pilot boring is defined as the diameter of the circle inscribing the inner contour of the pilot boring. When choosing the outer circle diameter of the deformed pilot boring smaller than the outer circle diameter of the component to be held, a sufficient allowance for the subsequent machining is ensured.
In advantageous embodiments, a one-dimensional deformation force is applied to the base body in order to machine the base body, i.e. for forming or widening the at least one opening. A compressive or a traction force can be applied in a first direction as a one-dimensional deformation force. The direction of the one-dimensional deformation force is referred to as the load direction. Application of a one-dimensional compressive force leads to the base body being compressed in the load direction and being stretched in a direction perpendicular to the load direction. By contrast, application of a one-dimensional tensile force leads to the base body being stretched in the load direction and being compressed in a direction perpendicular to the load direction. A relationship between stretching and compression depends on material properties such as Poisson's ratio and Young's modulus. In advantageous embodiments, a compressive force is applied to the base body as a deformation force. As mentioned previously, a joining force applied for the assembly corresponds, in magnitude and direction, to a deformation force applied for the production of the support structure in advantageous embodiments. In other embodiments, a one-dimensional compressive force is applied in a first direction in order to produce the support structure, whereas a traction force is applied as a joining force in a second direction, which is perpendicular to the direction of the compressive force.
In embodiments of the disclosure, a plurality of cut-outs is chosen depending on an application, for example an annular, elliptic, honeycomb-shaped or multiangular arrangement.
In an advantageous embodiment, a plurality of cut-outs are formed in the base body, wherein the cut-outs are arranged with a uniform distribution in a staggered relation with one another in at least the load direction and perpendicular to the load direction. In the context of the application, a uniform distribution refers to a distribution in which the distances between two cut-outs are constant. As a result of the uniform distribution, regions between the cut-outs have a uniform rigidity under extension in the case of uniform material properties. This results in an at least substantially uniform deformation of the cut-outs as a result of the applied deformation force.
In other words, the cut-outs are arranged in substantially parallel or parallel staggered rows resulting in a substantially hexagonal arrangement. As a result of the arrangement in rows, a space-saving arrangement of the components is possible in limited installation-space conditions. With the staggered arrangement rigidity webs, i.e. regions with high rigidity under extension or high extensional stiffness as a result of the increased amount of material, are omitted between the individual rows and columns.
In advantageous embodiments, the deformation force is applied in the direction of a row or a column. As a result, there is a deformation in the direction of the deformation force and perpendicular to the direction of the deformation force. If circular openings are formed, this respectively results in an oval deformation of the openings as a result of the restoration forces when the force is removed or withdrawn and the openings are deformed, wherein a diameter in the direction of the semi-minor axis is less than a diameter of the circular opening, whereas a diameter in the direction of the semi-major axis is greater than a diameter of the circular opening. If circular-cylindrical-shaped components are inserted into cut-outs shaped thus, the diameter of the circular opening in advantageous embodiments is selected to be greater than the diameter of the circular-cylindrical-shaped components in order to allow simple joining. Furthermore, the diameter of the circular opening is selected such that a diameter of the cut-out after the deformation force has been removed or reduced is less than a diameter of the circular-cylindrical-shaped components in the direction of the semi-minor axis. Thus, if a component has been inserted, complete recovery is no longer possible when the deformation force is removed or reduced. Rather, this results in a pressure contact between a held component and the cut-out at four strip-shaped contact faces that are distributed around the circumference of the clamped component. Such contact faces permit reliable centring and orientation of the components.
In an advantageous embodiment, a compensation structure is provided at at least one edge region of the base body such that an extensional stiffness of the base body in a region surrounding a cut-out adjacent to the edge region at least substantially corresponds to an extensional stiffness of the base body in a region surrounding a centrally arranged cut-out. In this case, a centrally arranged cut-out refers to a cut-out that, at least in the force direction or perpendicular to the force direction, is not adjacent directly to the edge region, but adjoins at least one further cut-out. Hence, what is attained by the compensation structure is that an extension characteristic of a cut-out adjacent to the edge region substantially corresponds to an extension characteristic of a centrally arranged cut-out. As a result, a uniform deformation of the cut-outs is achieved by applying a one-dimensional deformation force.
In one embodiment, openings, which cut the edge region and correspond to the openings in terms of shape and size, are formed in order to form a compensation structure on a side face of the base body running substantially parallel to the one-dimensional deformation force. In other words, the row of openings for the cut-outs is continued over the edge region, with open openings being formed in the edge region.
Provision is made in a further embodiment for circular-arc-shaped relief cuts to be formed in order to form a compensation structure on a side face of the base body running substantially normal to the one-dimensional deformation force. As a result, a closed edge structure for introducing the force is developed on the side face. However, at the same time the relief cuts afford the possibility of preventing points with increased rigidity under extension.
According to a second aspect of the disclosure, a method is provided for connecting at least two components to a support structure. The support structure has at least two cut-outs for holding the at least two components. The support structure is reversibly deformed into a joining state by applying a joining force. The at least two cut-outs are deformed into deformed cut-outs. In the joining state, each deformed cut-out forms a clearance fit with a component to be held. The components are inserted into the associated deformed cut-outs in the joining state, and the joining force is removed or reduced after the at least two components have been inserted so that an at least partial recovery of the deformed cut-out brings about a pressure contact between a held component and the associated cut-out in predefined circumferential regions.
In advantageous embodiments, the joining force applied for the assembly substantially corresponds, in direction and magnitude, to the deformation force applied during the production of the support structure. Hence, the joining state substantially corresponds to the braced state during production. The components, which form a clearance fit with the associated cut-outs in the joining state, can easily be inserted into the cut-outs during the joining state. After the deformation force has been removed or reduced, restoration forces act on the support structure, and so the components are held in the cut-outs in a clamping fashion. In the process, the support structure does not return completely to the original state but remains deformed, and so the restoration forces act as clamping forces.
The connection between the support structure and the components can be released again when desirable, for example if a component should be replaced or if the angular orientation of a component should be corrected. In order to release the connection, a force can likewise be applied, which, in advantageous embodiments, corresponds to the joining force, applied for the joining, in terms of magnitude and direction, and so there once again is a clearance fit between the cut-outs, deformed as a result of the joining force, and the components. In other embodiments, it is desirable to apply a greater force to release the connection because the components are stuck in the support structure, for example as a result of corrosion or the like.
In advantageous embodiments, a plurality of components are simultaneously picked-up by a suitable assembly apparatus and are simultaneously inserted into the cut-outs. In advantageous embodiments, at least one component is, after the insertion, aligned with respect to at least one degree of freedom in the associated cut-out before the joining force is removed or reduced. In the context of the disclosure, aligning refers to any relative motion between the support structure and the at least one component, as a result of which the component is moved into a desired position and/or angular position with respect to the support structure.
In another further embodiment, the support structure and/or a second support structure is connected to the at least one component via a non-releasable connection technique. In one embodiment, the first support structure is used for precise positioning of the components. The precisely positioned components are subsequently connected permanently to a second support structure and/or the support structure via a non-releasable connection technique, such as bonding, welding or soldering. Here, in the context of the disclosure, a non-releasable connection technique refers to a connection technique that can only be released by destroying a component and/or by dissolving the material used for the connection.
According to a further aspect of the application, an assembly is provided, which includes a support structure having an at least partly reversibly deformable base body with at least two cut-outs and at least two components, which are each held in one cut-out by force-fit. The support structure is at least in part reversibly deformable into a joining state by a joining force. The at least two cut-outs are deformed into deformed cut-outs in the joining state. The deformed cut-outs in the joining state form a clearance fit with the components to be held. At least partial recovery of the cut-out after the joining force is removed or reduced brings about a pressure contact between held components and the associated cut-outs in predefined circumferential regions.
In advantageous embodiments, the support structure includes a flat-shaped base body. In the context of the application, a flat-shaped or plate-like base body refers to a design in which an extent in the axial direction of the at least one cut-out is less than extents perpendicular to the direction of the cut-out. In advantageous embodiments, such a base body has a planar surface area perpendicular to the direction of the cut-out. In other embodiments, the surface area perpendicular to the direction of the cut-out has a convex and/or concave curvature.
In advantageous embodiments, an assembly is provided, which includes a support structure with a plurality of cut-outs and a multiplicity of identical or similar components, which are each held by force-fit in a cut-out of the support structure. The cut-outs are arranged and formed such that uniform interference-fit forces act on identical or similar components after the joining force is removed.
For this purpose, provision is made in one embodiment for differences to be taken into account in a deformation profile of individual cut-outs when forming or finely machining the openings such that openings with different shapes are formed.
Provision is made in advantageous embodiments for the cut-outs to be arranged with a uniform distribution in at least a force direction of a one-dimensional in a staggered relation joining force and perpendicular to the force direction of the one-dimensional joining force.
In a further embodiment, a compensation structure is provided at at least one edge region of the base body such that an extensional stiffness of the base body in a region surrounding a cut-out adjacent to the edge region at least substantially corresponds to an extensional stiffness of the base body in a region surrounding a centrally arranged cut-out.
Further advantages of the disclosure emerge from the claims and from the following description of exemplary embodiments of the disclosure, which are schematically illustrated in the drawings. Uniform reference signs are used in the drawings for equivalent or similar components. Features described or illustrated as part of one exemplary embodiment can likewise be used in another exemplary embodiment in order to obtain a further embodiment of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically shows a method for producing a support structure;
FIG. 2 schematically shows a method for assembling a component in a support structure as per FIG. 1 ;
FIG. 3 schematically shows a perspective illustration of a support structure when a deformation force is applied; and
FIG. 4 schematically shows a perspective illustration of the support structure as per FIG. 3 after the deformation force has been removed, with schematically indicated contact faces.
DETAILED DESCRIPTION
FIG. 1 schematically shows a method for producing a support structure 1 with a plurality of cut-outs 2 , into which components 3 , 103 , only illustrated very schematically in FIG. 1 , can be inserted with a force fit.
In the schematically illustrated method, pilot bores 20 with a diameter d 1 are initially formed into a base body 10 in a step (a). In the process, no deformation forces act on the base body 10 . The diameter d 1 of the pilot bores 20 is selected such that a sufficient allowance remains for subsequent fine-machining.
The support structure is deformed in step (b) for subsequent fine-machining by applying a suitable lateral deformation force F. In the illustrated exemplary embodiment, the base body 10 has a substantially rectangular surface area with two side faces 11 , 12 , with the deformation force F being applied to a first side face 11 and the load direction of the deformation force corresponding to the normal direction of the first side face 11 . The pilot bores 20 are deformed as a result of the deformation force F, and so deformed pilot bores 20 a are formed. The deformed pilot bores 20 a have an oval, more particularly substantially elliptical shape.
In the illustrated exemplary embodiment, a compressive force is applied as a deformation force F. As a result, the pilot bores 20 are deformed such that a diameter d 2 of the deformed pilot bores 20 a perpendicular to the load direction is greater than the diameter d 1 of the undeformed pilot bores 20 . By contrast, a diameter d 3 of the deformed pilot bores 20 a in the force direction of the deformation force F is less than the diameter d 1 of the undeformed pilot bores 20 . In an alternative embodiment (not illustrated), a traction force is applied as a deformation force. If a traction force is applied, the pilot bores 20 are deformed such that a diameter perpendicular to the load direction of the deformation force is less than the diameter d 1 of the undeformed pilot bores 20 , whereas a diameter in the force direction of the deformation force is greater than the diameter d 1 of the undeformed pilot bores 20 .
Fine-machining of the deformed pilot bores 20 a then takes place in step (c), and so openings 2 a are formed, which have a diameter d 4 that is greater than the small diameter d 3 of the deformed pilot bores 20 a . In the process, the openings 2 a are formed in terms of shape and size such that schematically illustrated components 3 , 103 to be held can be inserted with play in the braced state of the support structure 1 , which state is illustrated in FIG. 1( c ). Here, a first schematically indicated component 3 to be held has a circular-cylindrical-shaped contact region with a diameter D. A second schematically indicated component 103 to be held has a hexagonal contact region with an enveloping diameter or outer circle diameter D 2 .
The deformed pilot bores 20 a are widened during the fine-machining to a desired size and shape. In advantageous embodiments, the widening is brought about by boring, reaming, turning and/or honing, wherein small production tolerances can be obtained depending on the selection of the machining type. By way of example, production tolerances of the order of micrometers can be obtained when machining by honing and/or reaming. Circular-cylindrical cut-outs 2 a are created in the illustrated exemplary embodiment, the diameter d 4 of which is selected to be greater than the larger diameter d 2 of the deformed pilot bores 20 a and greater than the diameters D, D 2 of the components 3 , 103 .
The deformation force F is reduced after machining of the openings 2 a . The deformation force F can be removed such that the base body 10 recovers back to its original shape. As a result of the deformation force F being removed, the base body 10 relaxes and the precisely produced openings 2 a are deformed, as illustrated in FIG. 1( d ), such that the cut-outs 2 are formed. The cut-outs 2 have an oval shape, more particularly a substantially elliptical shape. As mentioned, a compressive force is applied as a deformation force F in the illustrated exemplary embodiment. Hence, when the base body 10 relaxes, the openings 2 a are deformed such that a diameter d 5 of the cut-outs 2 in the load direction of the deformation force F is greater than the diameter d 4 of the openings 2 a . By contrast, a diameter d 6 of the cut-outs 2 perpendicular to the load direction of the deformation force F is less than the diameter d 4 of the openings 2 a . Furthermore, the proportions are selected such that a diameter d 6 is less than or equal to the diameters D, D 2 of the components 3 , 103 .
In order to assemble the components 3 , 103 as illustrated in FIG. 2 , a joining force F 2 is applied in step (a) as per FIG. 2 like in step (c) as per FIG. 1 . As a result of the joining force F 2 , the cut-outs are deformed such that this results in deformed cut-outs 2 b . The joining force F 2 applied for the assembly can, in terms of direction and magnitude, correspond to the deformation force F applied when machining the deformed pilot bores 20 a . As a result, the deformed cut-outs 2 b once again assume the shape and/or size illustrated in FIG. 1( c ). In this form of the cut-outs 2 b , the associated components 3 , 103 can be inserted into the support structure 1 and can be positioned relative to the support structure 1 , more particularly they can be aligned in terms of their angular orientation and/or height relative to the support structure 1 . The joining force F 2 is once again reduced or removed in a subsequent step (b). As a result, there is a recovery of the support structure 1 and the cut-outs 2 . However, the inserted components 3 , 103 prevent a complete recovery of the cut-outs 2 , and so the components 3 , 103 inserted into cut-outs 2 are clamped into the cut-outs 2 due to the resulting restoration forces.
A deformation profile of the cut-outs 2 when a component 3 is clamped and resultant contact faces between the support structure 1 and the inserted components 3 , 103 depend on the shape of the cut-outs 2 , the arrangement of the cut-outs 2 on the support structure 1 , the shape of the utilized components 3 , 103 and on the direction and magnitude of the applied joining force F 2 .
In the illustrated exemplary embodiment, substantially circular-cylindrical-shaped cut-outs 2 a are machined into the base body 10 arranged in staggered rows, i.e. rows which are offset in line with the gap. Circular-cylindrical components 3 are inserted into the circular-cylindrical-shaped cut-outs 2 a , wherein proportions are selected such that a diameter d 6 of the deformed cut-out 2 is less than a diameter D of the components 3 . As schematically indicated in FIG. 4 , this results in four strip-shaped contact faces on a circumference of a held circular-cylindrical-shaped component 3 .
The connection technique according to the disclosure is advantageous in that the connection between the support structure 1 and the schematically illustrated components 3 , 103 can be released. As a result, it is possible to make subsequent adjustments, and also to replace components. Moreover, when assembling the components in the support structure 1 , it is possible to determine precisely a time at which the components should be clamped. As a result, it is possible to place a multiplicity of components in a precise fashion, and to align these in a suitable fashion.
In a further embodiment, the connection technique according to the disclosure is used to fix the components in their position via the support structure 1 , in order subsequently to connect the components to a second support structure via a non-releasable connection technique such as bonding, welding or soldering.
FIG. 3 schematically shows a section of an exemplary embodiment of a support structure 1 according to the disclosure with cut-outs 2 in a deformed state as a result of a joining force F 2 . In the illustrated exemplary embodiment, the cut-outs 2 are substantially circular in the deformed state, and so cylindrical components (not illustrated in FIG. 3 ), produced for a clearance fit, can easily be inserted and can be aligned, at least in respect of their angular orientation. Here, the cut-outs 2 are arranged in parallel rows, offset in line with the gap. The alignment in line with the gap prevents rigidity webs, i.e. regions with increased rigidity under extension as a result of a continuous cross-sectional area that is not interrupted by cut-outs 2 . This ensures that the cut-outs 2 can be deformed in the direction of the rows and perpendicular to the direction of the rows when a one-dimensional deformation or joining force is applied thereon in the direction of a row of the cut-outs or perpendicular to the direction of the rows.
Moreover, in the exemplary embodiment illustrated in FIG. 3 , compensation structures are provided on the edge regions of the base body 10 . In the illustrated embodiment the joining force is applied to a side face 11 .
In the illustrated exemplary embodiment, the row of cut-outs 2 is continued by openings 4 cutting the edge region in order to form a compensation structure on a side face 12 of the base body 10 running substantially parallel to the joining force F 2 . A distance between an opening 4 and an adjacent cut-out 2 in this case corresponds to the distance between two cut-outs 2 in the direction of the row. In terms of shape and size, the openings 4 correspond to the cut-outs 2 , wherein semi-circular-shaped openings 4 are formed on the side face 12 as a result of the difference with the edge region.
Circular-arc-shaped relief cuts 5 are provided on a side face 11 of the base body 10 running substantially perpendicular to the joining force F 2 . As a result, this creates a closed edge structure on the side face 11 for introducing the force of the joining force F 2 .
Quadrant-shaped openings 6 are provided in the corner regions between the side faces 11 , 12 .
By providing the openings 4 , the relief cuts 5 and the openings 6 , an extensional stiffness of the base body 10 in a region surrounding a cut-out 2 adjacent to the edge region substantially corresponds to an extensional stiffness of the base body 10 in a region surrounding a centrally arranged cut-out 2 .
Provided that the material of the base body 10 has uniform material properties, the achievement of this is that all cut-outs 2 have a uniform deformation profile when the joining force F 2 is applied.
FIG. 4 schematically shows the support structure 1 as per FIG. 2 after the joining force F 2 has been removed, with line-shaped or stripe-shaped contact faces 23 between the support structure 1 and the components (not illustrated in FIG. 3 ) being illustrated in a schematic fashion. The inserted components (not illustrated) prevent the support structure 1 from returning to a completely relaxed shape after the joining force F 2 is removed or reduced. Instead, the components are clamped as a result of the force resulting from the remaining deformation.
In the exemplary embodiment as per FIGS. 3 and 4 , the cut-outs 2 are arranged in parallel staggered rows. When the joining force F 2 is removed or reduced, four strip-shaped contact faces 23 emerge on the lateral surfaces of the cylindrical components as a result of the circular form of the cut-outs 2 in the braced or deformed state, illustrated in FIG. 3 , and a cylindrical form of associated components and as a result of the transverse contraction perpendicular to the direction of the joining force F 2 . Such contact faces 23 allow reliable centring and orientation of the components.
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A method is provided for producing a support structure including an at least partly reversibly deformable base body with a cut-out. A component can be held in the cut-out by friction. The method includes machining the base body in the braced state, wherein an opening is introduced into the base body and/or widened. The opening is deformed when the deformation force is removed such that the cut-out is formed. The opening is formed such that the application of a joining force makes it possible to deform the cut-out such that a component to be held can be introduced into the deformed cut-out with a clearance fit and an at least partial recovery of the deformed cut-out brings about a pressure contact between the held component and the cut-out in predefined circumferential regions.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims benefit under 35 U.S.C. §119(e) to U.S. Provisional Application No. 62/324,411, filed Apr. 19, 2016, which is incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates generally to self-contained trailers useful in hydraulic fracturing, and more specifically to a portable turbine power plant operable to generate AC electric power.
Background Information
[0003] Hydraulic fracturing is the fracturing of rock by a pressurized liquid. Some hydraulic fractures form naturally, certain veins or dikes are examples. Induced hydraulic fracturing or hydrofracturing is a technique in which typically water is mixed with sand and chemicals, and the mixture is injected at high pressure into a wellbore to create fractures, which form conduits along which fluids such as gas, petroleum, and groundwater may migrate to the well. The technique is very common in wells for shale gas, tight gas, tight oil, and coal seam gas.
[0004] A hydraulic fracture is formed by pumping the fracturing fluid into the wellbore at a rate sufficient to increase pressure downhole to exceed that of the fracture gradient (pressure gradient) of the rock. The fracture gradient is defined as the pressure increase per unit of the depth due to its density and it is usually measured in pounds per square inch per foot or bars per meter. The rock cracks and the fracture fluid continue further into the rock, extending the crack still further, and so on. Operators typically try to maintain “fracture width”, or slow its decline, following treatment by introducing into the injected fluid a proppant—a material such as grains of sand, ceramic, or other particulates that prevent the fractures from closing when the injection is stopped and the pressure of the fluid is reduced. Consideration of proppant strengths and prevention of proppant failure becomes more important at greater depths where pressure and stresses on fractures are higher. The propped fracture is permeable enough to allow the flow of formation fluids to the well. Formation fluids include gas, oil, salt water, fresh water and fluids introduced to the formation during completion of the well during fracturing.
[0005] Fracturing is typically performed by large diesel-powered pumps. Such pumps are able to pump fracturing fluid into a wellbore at a high enough pressure to crack the formation, but they also have drawbacks. Driving such pumps may rely on methods for supplying electrical power, including integrated power networks to facilitate power distribution to operate motors driving the pumps. Presently, such power generation requires large trailers for housing such systems at production fields. What is needed is an electric power generating system that does not create a large footprint.
SUMMARY OF THE INVENTION
[0006] The present invention relates to a portable power generation system for use in a fracturing plant. Equipment is mounted on a trailer and is delivered to a well site with a tractor. Pumps are driven by motors powered by a turbine mounted on the trailer, where motors are controlled by associated electronics.
[0007] In one embodiment, a portable power generation system is disclosed including a turbine generator, mounted on a first trailer, operable to generate AC electrical power electrically coupled to a remote fault protector by at least six (6) first high voltage AC (HVAC) conductors, where the remote fault protector is electrically coupled by at least six (6) second HVAC conductors to a rectifier assembly operable to generate DC electrical power; at least one inverter unit, mounted on a second trailer, electrically coupled to the rectifier assembly by at least two (2) first high voltage DC (HVDC) conductors, where the at least one inverter unit comprises an inverter control and disconnect section and an inverter cell section, where the inverter unit is operable to generate AC electrical power; and at least one electrical motor, mounted on the second trailer, electrically connected to the at least one inverter unit by at least two (2) third HVAC conductors, where the motor drives one or more well service pumps.
[0008] In one aspect, the rectifier assembly is a 12-pulse rectifier assembly.
[0009] In another aspect, the inverter control and disconnect section comprises a DC bus single pole/single throw (SPST) disconnect, a DC reactor, and a VFD input contactor, where the VFD input contactor is electrically coupled to a pre-charge board, and where the inverter control and disconnect section are electrically coupled to the inverter cell section.
[0010] In one aspect, the second trailer comprises two (2) inverter units and two (2) electric motors.
[0011] In another aspect, the turbine is a gas or diesel turbine. In a related aspect, the turbine is a 4 MW, 6-phase, 120 Hz turbine.
[0012] In one aspect, the first and second HVAC conductors are 2300V AC conductors. In another aspect, the first HVDC conductors are 6400 V DC conductors.
[0013] In one aspect, the inverter cell section comprises a 770 A, 18-cell inverter, having a 6400V DC input and a 4160V AC output. In another aspect, the third HVAC conductors are 4160V AC conductors. In a related aspect, the at least one electric motor is a 2500 HP, 4160V AC motor.
[0014] In one embodiment, a portable power generation system is disclosed including a 6-phase, 120 HZ turbine generator, mounted on a first trailer, operable to generate AC electrical power electrically coupled to a remote fault protector by at least six (6) first high voltage AC (HVAC), 2300 V AC conductors, where the remote fault protector is electrically coupled by at least six (6) second HVAC, 2300V AC conductors to a 12-pulse rectifier assembly operable to generate DC electrical power; two (2) inverter units, mounted on a second trailer, electrically coupled to the rectifier assembly by at least two (2) first high voltage DC (HVDC) conductors, where each the two (2) inverter units comprise an inverter control and disconnect section and an inverter cell section, where the each two (2) inverter units are operable to generate AC electrical power; and two (2) electrical motors, mounted on the second trailer, where each electric motor is electrically connected separately to one of the two (2) inverter units by a set of at least two (2) third HVAC conductors, where each motor drives one or more well service pumps.
[0015] In a related aspect, the service pump is a quintuplex plunger-style fluid pump. In a further related aspect, the service pump is a triplex plunger style fluid pump.
[0016] In another embodiment, a portable power generation system is disclosed including a turbine generator, mounted on a first trailer, operable to generate AC electrical power electrically coupled to a remote fault protector by at least six (6) first high voltage AC (HVAC) conductors, where the remote fault protector is electrically coupled by at least six (6) second HVAC conductors to a 12-pulse rectifier assembly operable to generate DC electrical power; two (2) inverter units, mounted on a second trailer, electrically coupled to the rectifier assembly by at least two (2) first high voltage DC (HVDC) conductors, where each inverter unit includes:
a) an inverter control and disconnect section containing a DC bus single pole/single throw (SPST) disconnect, a DC reactor, and a VFD input contactor, where the VFD input contactor is electrically coupled to a pre-charge board; and b) an inverter cell section electrically coupled to the inverter control and disconnect section, which inverter cell section contains a 770 A, 18-cell inverter, having a 6400V DC input and a 4160V AC output; and two (2) electrical motors, mounted on the second trailer, where each electric motor is electrically connected separately to one of the two (2) inverter units by a set of at least two (2) third HVAC conductors, where each motor drives one or more well service pumps.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a schematic of the skid/trailer mounted variable frequency drive (VFD) single line.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Before the present devices, methods, and methodologies are described, it is to be understood that this invention is not limited to particular devices, methods, and conditions described, as such devices, methods, and conditions may vary. It is also to be understood that the terminology used herein is for purposes of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only in the appended claims.
[0021] As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Thus, for example, references to “a pump” includes one or more pumps, and/or devices of the type described herein which will become apparent to those persons skilled in the art upon reading this disclosure and so forth.
[0022] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the invention, as it will be understood that modifications and variations are encompassed within the spirit and scope of the instant disclosure.
[0023] As used herein, “about,” “approximately,” “substantially” and “significantly” will be understood by a person of ordinary skill in the art and will vary in some extent depending on the context in which they are used. If there are uses of the term which are not clear to persons of ordinary skill in the art given the context in which it is used, “about” and “approximately” will mean plus or minus <10% of particular term and “substantially” and “significantly” will mean plus or minus >10% of the particular term.
[0024] As used herein, “footprint” means the on-site area required to accommodate a fracturing operation.
[0025] As used herein, “trailer unit” may be a trailer that is part of a tractor-trailer or a container which is mountable onto a trailer that is part of a tractor-trailer.
[0026] The technique of hydraulic fracturing is used to increase or restore the rate at which fluids, such as petroleum, water, or natural gas can be recovered from subterranean natural reservoirs. Reservoirs are typically porous sandstones, limestones or dolomite rocks, but also include “unconventional reservoirs” such as shale rock or coal beds. Hydraulic fracturing enables the production of natural gas and oil from rock formations deep below the earth's surface. At such depths, there may not be sufficient permeability or reservoir pressure to allow natural gas and oil to flow from the rock into the wellbore at economic rates. Thus, creating conductive fractures in the rock is pivotal to extract gas from shale reservoirs because of the extremely low natural permeability of shale. Fractures provide a conductive path connecting a larger volume of the reservoir to the well. So-called “super fracking”, which creates cracks deeper in the rock formation to release more oil and gas, will increase efficiency of hydraulic fracturing.
[0027] High-pressure fracture fluid is injected into the wellbore, with the pressure above the fracture gradient of the rock. The two main purposes of fracturing fluid are to extend fractures and to carry proppant into the formation, the purpose of which is to stay there without damaging the formation or production of the well.
[0028] The blended fluids, under high pressure, and proppant are pumped into the well, fracturing the surrounding formation. The proppant material will keep an induced hydraulic fracture open, during or following a fracturing treatment. The proppant material holds the fractured formation open to enhance rate of gas or oil recovery. The fluid is normally water. A polymer or other additive may be added to the water to decrease friction loss as the water is pumped down a well. Water containing the polymer is usually called “slick water.” Other polymers may be used during a treatment to form a more viscous fluid. Proppant is added to the fluid to prevent closure of fractures after pumping stops.
[0029] Fluids make tradeoffs in such material properties as viscosity, where more viscous fluids can carry more concentrated proppant; the energy or pressure demands to maintain a certain flux pump rate (flow velocity) that will conduct the proppant appropriately; pH, various rheological factors, among others. Types of proppant include silica sand, resin-coated sand, and man-made ceramics. These vary depending on the type of permeability or grain strength needed. The most commonly used proppant is silica sand, though proppants of uniform size and shape, such as a ceramic proppant, is believed to be more effective. Due to a higher porosity within the fracture, a greater amount of oil and natural gas is liberated.
[0030] The fracturing fluid varies in composition depending on the type of fracturing used, the conditions of the specific well being fractured, and the water characteristics. A typical fracture treatment uses between 3 and 12 additive chemicals. Although there may be unconventional fracturing fluids, the more typically used chemical additives can include one or more of the following:
Acids—hydrochloric acid (usually 28%-5%), or acetic acid is used in the pre-fracturing stage for cleaning the perforations and initiating fissure in the near-wellbore rock. Sodium chloride (salt)—delays breakdown of the gel polymer chains. Polyacrylamide and other friction reducers—minimizes the friction between fluid and pipe, thus allowing the pumps to pump at a higher rate without having greater pressure on the surface. Ethylene glycol—prevents formation of scale deposits in the pipe. Borate salts—used for maintaining fluid viscosity during the temperature increase. Sodium and potassium carbonates—used for maintaining effectiveness of crosslinkers. Glutaraldehyde—used as disinfectant of the water (bacteria elimination). Guar gum and other water-soluble gelling agents—increases viscosity of the fracturing fluid to deliver more efficiently the proppant into the formation. Citric acid—used for corrosion prevention. Isopropanol—increases the viscosity of the fracture fluid.
[0041] Hydraulic-fracturing equipment used in oil and natural gas fields usually consists of a slurry blender, one or more high-pressure, high-volume fracturing pumps (typically powerful triplex or quintuplex pumps) and a monitoring unit. Associated equipment includes fracturing tanks, one or more units for storage and handling of proppant, high-pressure treating iron, a chemical additive unit (used to accurately monitor chemical addition), low-pressure flexible hoses, and many gauges and meters for flow rate, fluid density, and treating pressure.
[0042] The system as disclosed herein has the advantage of being able to use motors for driving pumps that still fit a standard trailer.
[0043] In embodiments, the components of the system as described, including the electric motors may be capable of operating during prolonged pumping operations, and at temperatures in the range of about 0° C. or lower to about 55° C. or greater. In addition, each electronic motor is coupled with a variable frequency drive(s) (VFD).
[0044] FIG. 1 shows a schematic for the VFD single line 10 as disclosed herein. As shown, the system 10 consists essentially of two (2) trailers 101 / 201 , where the first trailer 101 contains a turbine generator 102 , remote operation/fault detection device 103 and a pulse rectifier assembly 104 electrically connected by high voltage AC (HVAC) conductors 105 to convert AC power generated by the turbine generator 102 to DC power via the rectifier 104 . Power from the trailer 101 is transferred to the second trailer 201 via High Voltage DC (HVDC) conductors 106 (with ground), which conductors 106 are electrically connected to two (2) inverter units 201 , which inverter units 201 contain a inverter control and disconnect section 202 and an inverter cell section 203 . The inverter control and disconnect section 202 contains a single pole/single throw (SPST) DC bus 204 in electrical communication with a DC reactor 205 and pre-charge board 206 and a VFD input contactor 207 . The inverter control and disconnect section 202 is in electrical communication with the inverter cell section, which inverter cell section 203 contains a 770 A, 18-cell inverter 208 , having an input of 6400V DC and an output of 4160V AC. Each inverter 208 is in electrical communication with an electric motor 209 via three (3) 4160V AC conductors 210 , which motors 209 may then be electrically connected to one or more well service pumps (not shown).
[0045] Pump control and data monitoring equipment may be mounted on a control vehicle (not shown), and connected to the pumps, motors, and other equipment to provide information to an operator, and allow the operator to control different parameters of the fractioning operation.
[0046] Advantages of the present system include:
[0047] 1) Power generation, associated electronics and motors are integrated with the trailer.
[0048] 2) The trailer is self-contained and can function independently of other trailers or equipment at the site.
[0049] 3) Physical footprint reduced relative to systems necessary to produce same HP.
[0050] In embodiments, the turbine is a 4 MW, 120 Hz, 6-phase generator. In one aspect, the inverters weigh about 14,500 lbs. The dimensions as envisage would allow the power system as disclosed to be easily transported by conventional tractor trailer systems. The ability to transfer the equipment of the present disclosure directly on a truck body or two (2) to a trailer increases efficiency and lowers cost. In addition, by eliminating or reducing the number of trailers that carry the equipment, the equipment may be delivered to sites having a restricted amount of space, and may be carried to and away from worksites with less damage to the surrounding environment.
[0051] In embodiments, the systems as disclosed may also be used for off-shore sites. The systems as disclosed are smaller and lighter than the equipment typically used on the deck of offshore vessels, thus removing some of the current ballast issues and allowing more equipment or raw materials to be transported by the offshore vessels.
[0052] While the technology has been shown or described in only some of its forms, it should be apparent to one of skill in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the technology. Further, it is to be understood that the above disclosed embodiments are merely illustrative of the principles and applications of the present technology. Accordingly, numerous modifications may be made to the illustrative embodiments and other arrangements can be devised without departing for the spirit and scope of the present technology as defined by the appended claims.
[0053] All references recited are incorporated herein by reference in their entireties.
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A power system for use in hydraulic fracturing or fracking of wells is disclosed. The power system is generally self-contained on a transportable system, such as a trailer. The weight and configuration of the trailer must be sized to be hauled legally on United States roadways. The system components include a turbine generator, rectifier, inverter units and AC motors.
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BACKGROUND
Windows are poor thermal insulators and contribute significantly to building heat loss and energy inefficiency. The need to meet green building standards is driving the adoption of energy efficient insulated glass units including vacuum designs. A vacuum insulated glass unit 10 is shown in FIGS. 1 and 2 . Unit 10 includes two panes of glass 11 and 12 separated by a vacuum gap. Pillars 14 in the gap maintain the separation of glass panes 11 and 12 , which are hermetically sealed together by an edge seal 13 , typically a low melting point glass frit, surrounding the pillars. Manufacturing vacuum insulated glass units efficiently and cost effectively can present challenges, particularly with selection of suitable pillars, placement of the pillars, and sealing the glass panes together with the vacuum gap. Accordingly, a need exists for improved ways to make and install pillars for vacuum insulated glass units.
SUMMARY
A pillar delivery film, consistent with the present invention, includes a support film, a sacrificial material layer on the support film, and a plurality of pillars. Each pillar is at least partially embedded in the sacrificial material layer, which is capable of being removed from the pillars while leaving the pillars substantially intact.
Another pillar delivery film, consistent with the present invention, includes a support film, a plurality of molds on the support film, and a plurality of pillars located in the molds. The molds are composed of a sacrificial material, which is capable of being removed from the pillars while leaving the pillars substantially intact.
A pillar delivery pocket film, consistent with the present invention, includes a support film having a plurality of pockets formed within it and a plurality of pillars located in the pockets. The support film is composed of a sacrificial material, which is capable of being removed from the pillars while leaving the pillars substantially intact.
Another pillar delivery pocket film, consistent with the present invention, includes a support film having a plurality of pockets formed within it, a sacrificial material located within the pockets, and a plurality of pillars at least partially embedded in the sacrificial material in the pockets. The sacrificial material is capable of being removed from the pillars while leaving the pillars substantially intact.
A method for transferring pillars from a delivery film to a receptor surface, consistent with the present invention, includes providing a delivery film having a support film, a sacrificial material on the support film, and a plurality of pillars at least partially within the sacrificial material. The delivery film is laminated to a receptor surface with the pillars facing the receptor surface. The support film is removed while leaving the pillars on the receptor surface and at least a portion of the sacrificial material on the pillars. The sacrificial material is then removed while leaving the pillars remaining and substantially intact on the receptor surface.
A method for making a delivery film having pillars and transferring them to a receptor surface, consistent with the present invention, includes providing a support film with a releasable surface. A plurality of pillars are molded on the releasable surface of the support film using a mold applied to the releasable surface, and the mold is removed from the releasable surface while leaving the pillars substantially intact. The pillars are then transferred from the support film to a receptor surface.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, explain the advantages and principles of the invention. In the drawings,
FIG. 1 is an exploded perspective view of a vacuum insulated glass unit;
FIG. 2 is a side sectional view of a vacuum insulated glass unit;
FIG. 3 is a diagram of a pillar delivery film for transfer to a sacrificial material layer;
FIG. 4 is a diagram of a pillar delivery film for transfer to a sacrificial material layer;
FIG. 5 is a diagram of a pillar delivery film and method for transfer directly to glass;
FIG. 6 is a diagram of a pillar delivery film and method for transfer to a sacrificial material layer;
FIG. 7 is a diagram of a pillar delivery film and method having a sacrificial material mold on a support film;
FIG. 8 is a diagram of a pillar delivery film and method for transfer to a sacrificial material layer on a support film;
FIG. 9 is a diagram of a pillar delivery film and method for transfer to a sacrificial material layer on a support film;
FIG. 10 is a diagram of coated pre-formed pillars;
FIG. 11 is a top view of pocket tape for delivering pillars;
FIG. 12 is a side sectional view of a portion of the pocket tape;
FIG. 13A is a side sectional view of pocket tape having pre-formed pillars;
FIG. 13B is a perspective view of the pillar resulting from the pocket tape of FIG. 13A ;
FIG. 14A is a side sectional view of pocket tape having cured form-in-place pillars;
FIG. 14B is a perspective view of the pillar resulting from the pocket tape of FIG. 14A ;
FIG. 15A is a side sectional view of pocket tape having cured form-in-place pillars with adhesive;
FIG. 15B is a perspective view of the pillar resulting from the pocket tape of FIG. 15A ;
FIG. 16A is a side sectional view of pocket tape having cured form-in-place pillars with retention rings;
FIG. 16B is a perspective view of the pillar resulting from the pocket tape of FIG. 16A ;
FIG. 17A is a side sectional view of sacrificial pocket tape having cured form-in-place pillars;
FIG. 17B is a perspective view of the pillar resulting from the pocket tape of FIG. 17A ;
FIG. 18A is a side sectional view of carrier film and sacrificial pocket tapes having cured form-in-place pillars;
FIG. 18B is a perspective view of the pillar resulting from the pocket tape of FIG. 18A ;
FIG. 19A is a side sectional view of a pocket tape having cured form-in-place pillars in sacrificial pockets;
FIG. 19B is a perspective view of the pillar resulting from the pocket tape of FIG. 19A ;
FIG. 20 is a diagram of a pillar delivery film and method using a strippable tool;
FIG. 21 is a diagram of a pillar delivery film and method using a strippable tool with a sacrificial material layer;
FIG. 22 is a diagram of a pillar delivery film and method using a rotary tool; and
FIG. 23 is a diagram of a pillar delivery film and method using a strippable skin.
DETAILED DESCRIPTION
Embodiments of the present invention include pillar delivery films and methods that can be used to provide the pillars required for fabrication of vacuum insulated glass units. The delivery films contain the pillars, and the methods can use the films to place the pillars on glass panes. One method involves mechanically depositing the pillars onto a pocket film or a film with a releasable surface and lamination transferring the pillars onto glass. Another method involves molding the pillars in place on a pocket film or a film with a releasable surface and mechanically transferring the pillars to glass. Another method involves molding the pillars in place on a pocket film or a film with a releasable surface and lamination transferring the pillars onto glass. The mechanical transfer of pillars, referred to as pick and place, can use robotics for the movement and placement of the pillars. The mold in place of the pillars and lamination transfer of them are described below. The methods can also deliver the edge seal in the glass units. The delivery films and methods can make use of lamination transfer films.
Examples of pillars for vacuum insulated glass units are described in U.S. Patent Application Publ. No. 2015/0079313, which is incorporated herein by reference as if fully set forth. Examples of lamination transfer films are described in U.S. Patent Application Publ. No. 2014/0021492, which is incorporated herein by reference as if fully set forth.
FIG. 3 is a diagram of a pillar delivery film with a sacrificial material layer for transfer to glass. The delivery film includes a support film 16 , a sacrificial resin material 17 forming molds, and form in place pillars 18 . The pillars can optionally include a pre-formed pillar body 15 .
FIG. 4 is a diagram of a pillar delivery film with a sacrificial material layer for transfer to glass. The delivery film includes a support film 19 , a sacrificial resin material 20 can be a continuous or discontinuous layer on support film 19 , pre-formed pillars 21 , and an optional functional layer 22 on or around the pillars. As illustrated, pillars 21 can be on or at least partially embedded within material 20 . The pillars can optionally include pre-formed pillar bodies 15 .
FIG. 5 is a diagram of a section of a pillar delivery film and method for transfer directly to glass. The delivery film includes a support film 24 having a mold 25 . The mold is filled with a curable pillar resin 26 to form a filled mold on the support film (step 30 ). Alternatively a preformed pillar may be inserted into the mold before or after the curable resin fill. The support film is laminated to glass 27 (step 31 ), and the film and glass laminate is cured (step 32 ). Film 24 with mold 25 is removed (step 36 ), resulting in pillar 26 on glass 27 . Alternatively, a molded pocket tape 28 can be used. Pocket tape 28 is filled with a curable pillar resin to form pillar 26 (step 33 ). The filled pocket tape 28 is laminated to glass 27 (step 34 ), and tape and glass laminate is cured (step 35 ). Pocket tape 28 is removed (step 36 ), resulting in pillar 26 on glass 27 .
FIG. 6 is a diagram of a section of a pillar delivery film and method with a sacrificial material layer for transfer to glass. Mold 41 can optionally be on mold support film 40 . The mold is filled with a curable pillar resin 42 to form a filled mold (optionally on mold support film 40 ) (step 50 ). Mold 41 (or optionally mold support film 40 ) is laminated to transfer film 44 having a sacrificial material layer 43 (step 51 ), and the mold (optionally be on mold support film 40 ) and transfer film 44 laminate is cured (step 52 ). Mold 41 or optionally be on mold support film 40 is removed (step 56 ), resulting in pillar delivery film comprising pillar 42 on transfer film 44 with sacrificial material 43 between them. Alternatively, a molded pocket tape 45 can be used. Pocket tape 45 is filled with a curable pillar resin to form pillar 42 (step 53 ). The filled pocket tape 45 is laminated to transfer film 44 having sacrificial material layer 43 (step 54 ), and pocket tape and transfer film 44 laminate is cured (step 55 ). Pocket tape 45 is removed (step 56 ), resulting in pillar delivery film comprising pillar 42 on transfer film 44 with sacrificial material 43 between them.
FIG. 7 is a diagram of a section of a pillar delivery film and method having a sacrificial material mold on a support film. The delivery film includes a mold support film 60 having a sacrificial material mold 61 . The mold support film 60 may be the sacrificial mold 61 . Mold 61 is filled with a curable pillar resin 62 to form a filled mold on mold support film 60 (step 70 ). The resin material is cured (step 71 ), and uncured pillar resin is deposited on the cured resin material (step 72 ). Mold support film 60 is laminated to glass 63 (step 73 ), and the film and glass laminate is cured (step 74 ). Mold support film 60 is removed, leaving sacrificial material mold 61 on resin pillar 62 (step 75 ). The sacrificial material is baked out (step 79 ), resulting in pillar 62 on glass 63 . Alternatively, mold support film 60 is laminated to glass 63 without the uncured pillar resin (step 76 ), and the film and glass laminate is cured (step 77 ). Mold support film 60 is removed, leaving sacrificial material mold 61 on resin pillar 62 (step 78 ). The sacrificial material is baked out (step 79 ), resulting in pillar 62 on glass 63 .
FIG. 8 is a diagram of a section of a pillar delivery film and method for transfer to a sacrificial material layer on a transfer film and lamination to glass. A support film 80 includes a release surface or coating 81 . Using a continuous cast and cure process, a pillar 82 is formed on support film 80 (step 90 ), and support film 80 with pillar 82 is laminated to a transfer film 83 having a sacrificial material coating 84 (step 91 ). Support film 80 is removed, transferring pillar 82 to transfer film 83 (step 92 ). An optional adhesive 85 can be applied to pillar 82 (step 93 ). Transfer film 83 is laminated to glass 86 (step 94 ), and transfer film 83 is removed (step 95 ). Sacrificial material 84 is removed (step 96 ), resulting in pillar 82 on glass 86 with optional adhesive 85 . As illustrated, pillars 82 can be partially embedded within optional adhesive 85 .
FIG. 9 is a diagram of a section of a pillar delivery film and method for transfer to a sacrificial material layer on a support film. The delivery film includes a support film 100 with a release surface or coating 102 . Using a continuous cast and cure process, a pillar 103 is formed on support film 100 (step 110 ) with a pillar land 106 between pillars, and an adhesive 104 is deposited on pillar 103 (step 111 ). Support film 100 with pillar 103 is laminated to glass 105 (step 112 ). Support film 100 is removed (step 113 ), resulting in removal of pillar land 106 and transfer of pillar 103 to glass 105 with adhesive 104 .
FIG. 10 is a diagram of coated pre-formed pillars. A pre-formed pillar 120 is coated in a wet or dry coating process (step 123 ) to form a coating 121 surrounding pillar 120 . The coated pillar can then be transferred to glass 122 using, for example, the methods described above. Additional functional layers can also be optionally added to the coated pillar. Coating 121 can include, for example, an adhesive coating, an silsesquioxane precursor with nanoparticles, or a polymer derived ceramic.
FIG. 11 is a top view of pocket tape 130 for delivering pillars. Pocket tape 130 typically includes holes 131 to engage machine gears. Material pockets 132 are formed in pocket tape 130 . FIG. 12 is a side sectional view of a portion of the pocket tape 130 having pockets 132 . Pocket 132 includes a film portion 133 and a pocket portion 134 for using in forming, transferring, and delivering, pillars.
FIGS. 13A-19A are side sectional views of various pocket tapes used to form pillars, and FIGS. 13B-19B are perspective views of the resulting pillars. FIG. 13A is a side sectional view of a pocket tape 140 having pre-formed pillars 141 ( FIG. 13B ). FIG. 14A is a side sectional view of a pocket tape 142 having cured form-in-place pillars 143 ( FIG. 14B ). FIG. 15A is a side sectional view of a pocket tape 144 having cured form-in-place pillars 145 with an adhesive 146 ( FIG. 15B ). FIG. 16A is a side sectional view of a pocket tape 147 having cured form-in-place pillars 148 with adhesive 151 and adhesive retention rings 149 to limit the lateral spread of the adhesive ( FIG. 16B ) and a liner 150 . FIG. 17A is a side sectional view of a pocket tape 151 , formed from a sacrificial material, having cured form-in-place pillars 152 ( FIG. 17B ). FIG. 18A is a side sectional view of carrier film tape 153 and a sacrificial pocket tape 155 having cured form-in-place pillars 154 ( FIG. 18B ). FIG. 19A is a side sectional view of a pocket tape 156 having cured form-in-place pillars 157 in pockets formed from a sacrificial material 158 ( FIG. 19B ).
FIG. 20 is a diagram of a section of a pillar delivery film and method using a strippable tool 160 composed of a strippable film molds 161 . The delivery film includes a support film 162 having a sacrificial material 163 . Strippable tool 160 is laminated to support film 162 to create molds (step 170 ), and a curable pillar paste 164 is coated onto support film 162 (step 171 ), creating curable pillar 164 A and land 164 B. The filled support film 162 is cured (step 172 ), and an adhesive 165 is coated onto cured pillar 164 (step 173 ), creating an adhesive coating 165 A on the cured pillar 164 A and an adhesive coating 165 B on the cured land 164 B. Strippable tool 160 is removed (step 174 ), taking with it cured land 164 B and adhesive 165 B, resulting in zero land pillar transfer film having pillar 164 A on sacrificial material 163 and adhesive 165 A.
FIG. 21 is a diagram of a section of a pillar delivery film and method using a strippable tool 180 composed of a strippable film molds 181 with a sacrificial material layer 183 . The delivery film includes a support film 182 . Strippable tool 180 is laminated to support film 182 (step 190 ), and a curable pillar paste 184 is coated onto support film 182 (step 191 ), creating curable pillar 184 A and land 184 B. The filled support film 182 is cured (step 192 ), and an adhesive 185 is coated onto cured pillar 184 (step 193 ), creating an adhesive coating 185 A on the cured pillar 184 A and an adhesive coating 185 B on the cured land 184 B. Strippable tool 180 is removed (step 194 ), taking with it cured land 184 B and adhesive 185 B, resulting in a zero land pillar transfer film having pillar 184 A and sacrificial material 183 on support film 182 and adhesive 185 A on pillar 184 A.
FIG. 22 is a diagram of a pillar delivery film and method using a rotary tool having an opaque perforated rotary mold tool 200 and curing units 201 . The delivery film includes a support film 204 having a sacrificial material 205 . A pillar material 206 is applied to support film 204 through perforated rotary mold tool 200 and cured by curing units 201 (step 210 ), resulting in formed pillars on support film 204 when removed from perforated rotary mold tool 200 (step 211 ). An adhesive 207 is coated on pillar 206 (step 212 ), resulting in zero land pillar transfer film having pillar 206 on sacrificial material 205 and support film 204 and with adhesive 207 .
FIG. 23 is a diagram of a section of a pillar delivery film and method using a strippable skin, which is a type of strippable tool. The delivery film includes a structured film mold 220 with a strippable skin 222 or a replicated resin mold 221 on film 220 with strippable skin 222 . A curable pillar paste 223 is coated onto the mold film 220 (step 230 ), creating curable pillar 223 A and land 223 B, the filled mold film 220 is cured (step 231 ), and an adhesive 224 is coated on cured pillar 223 (step 232 ), creating an adhesive coating 224 A on the cured pillar 223 A and an adhesive coating 224 B on the cured land 223 B. Strippable skin 222 is removed (step 233 ), taking with it cured land 223 B and adhesive 224 B, resulting in a zero land pillar transfer film having pillar 223 on support film 220 and with an adhesive 224 .
In the fabrication processes described above, additional or supplemental steps can be used within the described steps. In the processes described above, or other processes of the present invention, the sacrificial material can be removed by being cleanly baked out or by being otherwise capable of removal. The term “cleanly baked out” means that the sacrificial material can be removed by pyrolysis or combustion without leaving a substantial amount of residual material such as ash. In some of the side sectional views of the delivery films described above, only one mold and corresponding pillar are shown for illustrative purposes only. The delivery films typically include many of the molds and pillars for delivery of the pillars to vacuum insulated glass units.
Exemplary materials for the processes described above are provided in the Examples. Exemplary materials for the pillars for the vacuum insulated glass units include the following: ceramic nanoparticles; ceramic precursors; sintered ceramic; glass ceramic; glass frit; glass beads or bubbles; metal; or combinations thereof.
EXAMPLES
Materials
Abbreviation or
Available
Trade Designation
Description
from
FILTEK Supreme+
paste
3M Company,
5032W 2009-04
St. Paul, MN
QPAC 40
poly(alkylene carbonate)
Empower Materials, Inc.,
copolymer
New Castle, DE
QPAC 100
poly(alkylene carbonate)
Empower Materials, Inc.,
copolymer
New Castle, DE
QPAC 130
poly(alkylene carbonate)
Empower Materials, Inc.,
copolymer
New Castle, DE
T50
silicon release liner
Solutia Inc.,
St. Louis, MO
Example 1
Replicated Mold of Sacrificial Material
A coating solution was prepared by dissolving enough of QPAC 40 in 1,3-dioxolane to produce a final weight percent of 30% QPAC 40. The coating solution was hand coated on the backside of a 0.051 mm (0.002 inch) thick T50 silicone release liner in a notch bar coater. Approximately 50 milliliters of the coating solution was applied to the T50 backside and pulled through a notch bar coater set with a gap of 0.024 inches. The coating was dried at ambient for 1 hour.
The coated film was placed on a hotplate coating side up and held at 50° C. until heated. A tool containing square protrusions on a 0.132 cm pitch was placed onto the coated film, protrusion side down. Individual square posts on this tool tapered at 6 degrees from 296 um at the base to 227 um at the top, and were 305 um tall. A 4.6 kg weight was placed onto the top of the tool, embossing the coating. The tool was allowed to contact the film at temperature for 5 minutes. The weight was removed from the tool and the assembly was removed from the hotplate, and allowed to return to room temperature. The tool was then removed. The coated film now contained wells in the coating that corresponded to the protrusions on the tool.
The wells in the film were then filled with FILTEK Supreme+ 5032W 2009-04 by applying the FILTEK Supreme+ paste to the film and doctoring off the excess with a spatula. The filled sample was then laminated to a clean glass slide at room temperature with a silicone hand roller. The resulting laminate was then cured under germicidal lamps for five minutes. The T50 liner was then removed, leaving cast posts attached to the glass slide, surrounded by the sacrificial mold.
Example 2
Replicated Mold of Sacrificial Material with Adhesive
A coating solution was prepared by dissolving enough of QPAC 40 in 1,3-dioxolane to produce a final weight percent of 30% QPAC 40. The coating solution was hand coated on the backside of a 0.051 mm (0.002 inch) thick T50 silicone release liner in a notch bar coater. Approximately 50 milliliters of the coating solution was applied to the T50 backside and pulled through a notch bar coater set with a gap of 0.024 inches. The coating was dried at ambient for 1 hour.
The coated film was placed on a hotplate coating side up and held at 50° C. until heated. A tool containing square protrusions on a 0.132 cm pitch was placed onto the coated film, protrusion side down. Individual square posts on this tool tapered at 6 degrees from 296 um at the base to 227 um at the top, and were 305 um tall. A 4.6 kg weight was placed onto the top of the tool, embossing the coating. The tool was allowed to contact the film at temperature for 5 minutes. The weight was removed from the tool and the assembly was removed from the hotplate, and allowed to return to room temperature. The tool was then removed. The coated film now contained wells in the coating that corresponded to the protrusions on the tool.
The wells in the film were then filled with FILTEK Supreme+ 5032W 2009-04 by applying the FILTEK Supreme+ paste to the film and doctoring off the excess with a spatula. The resulting laminate was then cured under germicidal lamps for five minutes. A second layer of FILTEK Supreme+ 5032W 2009-04 by applying the FILTEK Supreme+ paste to the film and doctoring off the excess with a spatula, leaving a thin layer of uncured FILTEK Supreme+ paste on top of the cured layer, imparting adhesion to the sample.
The sample was then laminated to a clean glass slide at room temperature with a silicone hand roller. The resulting laminate was then cured under germicidal lamps for five minutes. The T50 liner was then removed, leaving cast posts attached to the glass slide, surrounded by the sacrificial mold.
Example 3
Particle Delivery Film
A coating solution was prepared by dissolving enough of QPAC 40 in 1-3 dioxolane to produce a final weight percent of 5% QPAC 40. The coating solution was delivered at a rate of 30 cm 3 /min to a 10.2 cm (4 inch) wide slot-type coating die. After the solution was coated on the backside of a 0.051 mm (0.002 inch) thick T50 silicon release liner, the coated web traveled approximately 2.4 m (8 ft) before entering a 9.1 m (30 ft) conventional air floatation drier with all 3 zones set at 65.5° C. (150° F.). The substrate was moving at a speed of 3.05 m/min (10 ft/min) to achieve a wet coating thickness of about 80 micrometers.
A piece of the coated film slightly larger than 6 in×6 in was placed on a hotplate held at 50° C. Grade 36+ shaped abrasive particles prepared according to the disclosure of U.S. Pat. No. 8,142,531 having a side length of about 0.8 mm and about 0.2 mm thick, and a sidewall angle of 98 degrees. The particles were pressed into the heated film in a grid with 2 cm spacing, creating a particle delivery film. The particle delivery film was removed from the hotplate and brought to room temperature.
The cooled particle delivery film was laminated at 230 F, coating and particle side down to a 0.125 inch thick 6 in×6 in section of glass using a thermal film laminator (GBC Catena 35, GBC Document Finishing, Lincolnshire, Ill.). The laminated sample was allowed to cool to room temperature. The T50 liner was then removed, leaving the particles arranged on the substrate.
Example 4
Particle Delivery Film with Integrated Edge Seal
A coating solution was prepared by dissolving enough of QPAC 40 in 1-3 dioxolane to produce a final weight percent of 5% QPAC 40. The coating solution was delivered at a rate of 30 cm 3 /min to a 10.2 cm (4 inch) wide slot-type coating die. After the solution was coated on the backside of a 0.051 mm (0.002 inch) thick T50 silicon release liner, the coated film traveled approximately 2.4 m (8 ft) before entering a 9.1 m (30 ft) conventional air floatation drier with all 3 zones set at 65.5° C. (150° F.). The substrate was moving at a speed of 3.05 m/min (10 ft/min) to achieve a coated film with a wet coating thickness of about 80 micrometers.
A slurry was prepared consisting of glass particles and QPAC 40 in MEK. A screen-print mesh was prepared by masking a 5.75 in×5.75 in square with tape on the top of the screen. A second solid square 5.25 in×5.25 in was created with tape and centered in the first square to create a square opening in the mesh 0.25 in wide. A section of the coated film larger than 6 in×6 in was placed under the screen, and the screen pressed and held against the coated film with weights. The prepared slurry was forced through the opening in the screen-print mesh with foam applicators. The screen was removed, and the slurry was allowed to dry overnight at room temperature, creating an edge seal delivery film.
A piece of the edge seal delivery film slightly larger than 6 in×6 in was placed on a hotplate held at 50° C. Grade 36+ shaped abrasive particles prepared according to the disclosure of U.S. Pat. No. 8,142,531 having a side length of about 0.8 mm and about 0.2 mm thick, and a sidewall angle of 98 degrees. The particles were pressed into the heated film in a grid with 2 cm spacing, creating a particle delivery film. The particle and edge seal delivery film was removed from the hotplate and brought to room temperature.
The cooled particle and edge seal delivery film was laminated at 230° F., coating and particle side down to a 0.125 inch thick 6 in×6 in section of glass using a thermal film laminator (GBC Catena 35, GBC Document Finishing, Lincolnshire, Ill.). The laminated sample was allowed to cool to room temperature. The T50 liner was then removed, leaving the particles arranged on the substrate, and the edge seal arranged around the perimeter of the glass.
Example 5
Landless Replication Via Mask Method
A coating solution was prepared by dissolving enough of QPAC 40 in 1-3-dioxolane to produce a final weight percent of 5% QPAC 40. The coating solution was delivered at a rate of 30 cm 3 /min to a 10.2 cm (4 inch) wide slot-type coating die. After the solution was coated on the backside of a 0.051 mm (0.002 inch) thick T50 silicon release liner, the coated film traveled approximately 2.4 m (8 ft) before entering a 9.1 m (30 ft) conventional air floatation drier with all 3 zones set at 65.5° C. (150° F.). The substrate was moving at a speed of 3.05 m/min (10 ft/min) to achieve coated film with a wet coating thickness of about 80 micrometers.
A 2 mil perforated film was prepared by laser cutting (LaseX, Inc., White Bear Lake, Minn.) 500 micron diameter holes spaced on 2 cm centers into an 0.008 inch polypropylene film. The perforated film was laminated at 230° F., coating side down to a section of the coated film using a thermal film laminator (GBC Catena 35, GBC Document Finishing, Lincolnshire, Ill.). The laminated sample was allowed to cool to room temperature.
The wells in the film were then filled with FILTEK Supreme+ 5032W 2009-04 by applying the FILTEK Supreme+ paste to the film and doctoring off the excess with the edge of a glass microscope slide. The resulting film was then cured under germicidal lamps for five minutes.
The perforated film was peeled off of the substrate, leaving a particle delivery film that contained particles of cured FILTEK Supreme+ paste in the size and position of the holes in the perforated film.
The cooled particle delivery film was laminated at 230° F., coating and particle side down to a glass microscope slide using a thermal film laminator (GBC Catena 35, GBC Document Finishing, Lincolnshire, Ill.). The laminated sample was allowed to cool to room temperature. The T50 substrate was then removed, leaving the particles arranged on the glass, held by the QPAC 40 layer.
Example 6
Landless Replication with Adhesive Layer Via Mask Method
A coating solution was prepared by dissolving enough of QPAC 40 in 1-3 dioxolane to produce a final weight percent of 5% QPAC 40. The coating solution was delivered at a rate of 30 cm 3 /min to a 10.2 cm (4 inch) wide slot-type coating die. After the solution was coated on the backside of a 0.051 mm (0.002 inch) thick T50 silicon release liner, the coated film traveled approximately 2.4 m (8 ft) before entering a 9.1 m (30 ft) conventional air floatation drier with all 3 zones set at 65.5° C. (150° F.). The substrate was moving at a speed of 3.05 m/min (10 ft/min) to achieve coated film with a wet coating thickness of about 80 micrometers.
A 2 mil perforated film was prepared by laser cutting (LaseX, Inc., White Bear Lake, Minn.) 500 micron diameter holes spaced on 2 cm centers into an 0.008 inch polypropylene film. The perforated film was laminated at 230° F., coating side down to a section of the previously coated film using a thermal film laminator (GBC Catena 35, GBC Document Finishing, Lincolnshire, Ill.). The laminated sample was allowed to cool to room temperature.
The wells in the film were then filled with FILTEK Supreme+ 5032W 2009-04 by applying the FILTEK Supreme+ paste to the film and doctoring off the excess with the edge of a glass microscope slide. The resulting film was then cured under germicidal lamps for five minutes. A second layer of FILTEK Supreme+ 5032W 2009-04 by applying the FILTEK Supreme+ paste to the film and doctoring off the excess with a spatula, leaving a thin layer of uncured FILTEK Supreme+ paste on top of the cured layer, imparting adhesion to the sample.
The perforated film was peeled off of the substrate, leaving a particle delivery film that contained particles of cured FILTEK Supreme+ paste in the size and position of the holes in the film, with a thin layer of uncured FILTEK Supreme+ paste on the top of the columns.
The cooled particle delivery film was laminated at 230° F., coating and particle side down to a glass microscope slide using a thermal film laminator (GBC Catena 35, GBC Document Finishing, Lincolnshire, Ill.). The laminated sample was allowed to cool to room temperature. The resulting laminate was then cured under germicidal lamps for five minutes. The T50 liner and QPAC 40 substrate was then removed, leaving the particles arranged on the glass.
Example 7
Coated Encapsulated Pillars
A particle delivery film was created by applying FILTEK Supreme+ paste drop wise to 2 mil unprimed PET and grade 36+ shaped abrasive particles prepared according to the disclosure of U.S. Pat. No. 8,142,531 having a side length of about 0.8 mm and about 0.2 mm thick, and a sidewall angle of 98 degrees. The particles were pressed into the resin. The sample was crosslinked using 4 passes of ultraviolet irradiation (RPC Industries UV Processor QC 120233AN/DR, Plainfield, Ill.) at 50 f pm in air. Any excess resin surrounding the pillars was removed using a razor blade to create planarized pillars. The planarized pillars were released from the PET by flexing it in a tight radius.
A light microscope image at 50× of the FILTEK Supreme+ paste planarized slip cast pillar showed that the pillar appeared as a light core with an opaque nanoparticle resin planarizing one surface.
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Pillar delivery films for vacuum insulated glass units. The delivery films include a support film or pocket tape, a sacrificial material on the support film, and a plurality of pillars. The pillars are at least partially embedded in the sacrificial material or formed within sacrificial material molds, and the sacrificial material is capable of being removed while leaving the pillars substantially intact. In order to make an insulated glass unit, the delivery films are laminated to a receptor such as a glass pane, and the support film and sacrificial material are removed to leave the pillars remaining on the glass.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to contactors and more specifically to a direct current contactor for selectively closing the connection between a fixed pair of high current terminals by supplying a low current to the contactor.
[0002] Direct current contactors include a high current switch and a solenoid in a single enclosure. The switch provides the desired function, to turn current flow on and off. The solenoid serves as the actuator for the switch, thereby allowing the switch to be controlled remotely via a low current control device.
[0003] Most commonly, the switch portion is a normally open switch of the single pole single throw variety. In operation, the switch contacts are open with no power applied to the solenoid and are actuated to the closed condition when power is applied to the solenoid.
[0004] Direct current contactors are commonly used to supply power between a battery and starter for various over-the-road and off-road vehicles such as automobiles, trucks, tractors, construction machinery and the like. The contactor and solenoid are connected in a circuit between the battery, electric starter and starter switch. The contactor is connected in series with the battery and starter in a high current environment.
[0005] During the manufacturing process of a contactor, numerous components must be assembled in sequence. It is a further requirement that the components be retained from dislodgement and/or rotation during assembly and use. It is also desirable that the assembly gives the installer a tactile confirmation that the installation was completed without damage to the unit.
SUMMARY OF THE INVENTION
[0006] The present invention provides a reliable contactor that may be reconfigured to be grounded to a mounting bracket or a separate terminal. The contactor comprises a housing unit having at least two high current terminals and at least one low current coil terminal located and sealed within the surface of the housing unit, with one end of the terminal protruding into the housing unit, and one end of the terminal extending outward from the surface. The terminals are designed with a ribbed or knurled center area that prevents the terminals from rotating within the housing surface. Also included are several steps along the terminals axes to assist in seal integrity. The terminals further have a knurled surface on the outward connecting end of the terminal. The knurled surface assists in connecting to an external wire, cable, or other device, since the knurled surface also restricts terminal rotation.
[0007] The solenoid also comprises a bobbin with a conductive coil wrapped around the bobbin. The bobbin has a plurality of projections located on the outer edges of the bobbin's ends. The projections each have a chimney structure or retaining receptacle that permits holding of a spring within the chimney. The projections also have a slot that may receive a conductive terminal blade or coupling means. The spring retained in the chimney is in connection with the low current terminal or terminals, and possibly a contactor cover for a solenoid that is grounded to its mounting surface. The terminal blade connects the coil to the spring and allows a current to flow through the solenoid coil. The design of the chimneys allows for easy assembly of the solenoid with the contactor housing.
[0008] The housing unit of the contactor is designed to receive the bobbin in a mating arrangement that will prevent the bobbin from rotating within the housing once assembled. The housing design, which has preformed, longitudinally extending channels to receive the projections on the bobbin, also makes it easier to properly align the bobbin when inserting the solenoid assembly into the housing unit.
[0009] The overall design of the contactor allows for a more efficient assembly than prior contactor arrangements. These and other features will become evident in the following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of a contactor according to the present invention.
[0011] FIG. 2 is a cut-away view of the contactor shown along line 2 - 2 of FIG. 1 .
[0012] FIG. 3 is an exploded view of the contactor according to the present invention.
[0013] FIG. 4 is an interior bottom view of the solenoid housing.
[0014] FIG. 5 is a close-up perspective view of a high current terminal or stud used in the present invention for current transfer showing the top of the stud.
[0015] FIG. 6 is a close-up side view of a high current terminal or stud used in the present invention for current transfer showing the side of the stud.
[0016] FIG. 7 is an exploded view of the solenoid used in the present invention.
[0017] FIG. 8 is close-up sectional view of the projection area of the bobbin.
[0018] FIG. 9 is a cross-sectional view of a first embodiment of the contactor according to the present invention taken along the line 9 - 9 of FIG. 1 .
[0019] FIG. 10 is a cross-sectional view of a second embodiment of the contactor according to the present invention taken along line 10 - 10 of FIG. 1 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
[0021] A direct current contactor 10 according to the present invention can be seen generally in FIG. 1 . The contactor 10 is shown having a pair of high current studs or power terminals 12 and a pair of low current studs or terminals 14 . In the embodiment shown, the contactor is a normally open contactor of the single pole single throw variety. The contactor 10 may operate with more or fewer studs 12 and 14 as in, for example only, a single pole double throw contactor. This variety of contactor typically has three or four high current studs 12 whereby one set is normally open and the other is normally closed.
[0022] The high current stud 12 and the lower current stud 14 will be referred to in the description as single items for the sake of clarity and not as a limitation on the invention. The studs 12 and 14 each sit within a housing unit 16 , which is attached to an end plate, cover, or mounting bracket 18 . While the mounting bracket 18 is shown to be a unitary piece, it is conceivable that a cover without mounting structure may replace the mounting bracket 18 . In such an instance, separate attaching or clamping means would be used to secure the contactor 10 in place. Provided that the end plate or cover 18 secures the required elements within the housing unit 16 , any suitable structure may act as the mounting bracket 18 .
[0023] FIG. 2 is a cross-sectional perspective view of the contactor 10 . The studs 12 and 14 are nestled within the surface of the housing 16 . A portion of the outer surface of the low current stud 14 has a knurled surface 15 located where the stud 14 sits within the housing 16 , thereby restricting rotation of the stud 14 within the housing 16 . A similar design located on the high current stud 12 will be discussed with respect to FIGS. 5 and 6 . The high current studs 12 make contact with a contact disc 20 , which is attached to an armature or plunger rod 22 . The plunger rod 22 is biased against the housing 16 by way of a headspring 24 . The headspring is nestled within a well 60 that holds the headspring 24 in proper alignment. A seal spring 26 maintains the static position of the contact disc 20 and allows the solenoid to over-travel to its internal stopping point thereby providing the contact disc 20 with a predefined load on the high current studs 12 . The coil 30 allows a magnetic flux to pass to the plunger 78 , which is forced upward and persuades the plunger rod 22 upward which in turn moves the contact disc 20 to make a connective bridge between the high current studs 12 . The seal spring 26 preferably is of a high force design that provides for a low milivolt drop between the high current studs 12 . The seal spring 26 is also preferably an inverted conical design to provide for a stable platform for the contact disc 20 to rest upon.
[0024] Still referring to FIG. 2 , at least one low current terminal 14 is connected to a coil spring 32 , which is in contact with a coupling means or terminal blade 34 . The coil spring 32 is shown to be helical in shape, but any conductive connecting means that will transfer a current from the terminal 14 to the coil 30 via the terminal blade 34 will suffice. The terminal blade 34 is connected to the coil 30 , thereby allowing an electrical connection for the low current coil terminal 14 through the spring 32 to the coil 30 . As also shown in FIG. 2 , in one contactor embodiment a similar lower spring 36 may be placed on the opposite side of the bobbin 28 , thereby allowing the coil assembly to be grounded to a grounding means through its mounting cover 18 .
[0025] FIG. 3 is an exploded view of the contactor 10 . The various elements of the contactor 10 are designed to easily fit within the housing 16 . The headspring 24 and the contact disc 20 , which is supported by the seal spring 26 , sit on the plunger rod 22 . The headspring 24 is fitted onto and mates with a ridged end 38 of the plunger rod 22 , while a C-clip 40 that fits into a groove 42 holds the contact disc 20 in place. The mating of the headspring 24 and the ridged end 38 allows placement of the headspring 24 into the well 60 (see FIGS. 2 and 4 ) when the assembly is inverted, without needing to independently hold the headspring 24 in place. Such an arrangement eases manufacturing and allows for a less frustrating assembling process. The seal spring 26 slides over the plunger rod 22 and sits between a shoulder on the plunger rod 22 and the contact disc 20 . Insulating washers 44 and 46 sandwich the seal spring 26 .
[0026] Still referring to FIG. 3 , the bobbin 28 has a pair of bobbin ends 47 with a plurality of projections 47 a extending from the bobbin ends 47 . In a preferred embodiment, the upper bobbin end 47 will have two projections 47 a located on it, while the bottom bobbin end 47 will have one projection 47 a located on it. The bobbin 28 , bobbin ends 47 , flanges 47 a , and receptacles 48 may be molded as one piece or as individual pieces and secured together afterwards. The coil springs 32 are slid into respective chimneys or receptacles 48 that are attached to the projections 47 a . The receptacles 48 hold the coil springs 32 in place, even if the bobbin 28 is inverted for insertion into the housing 16 . The chimneys 48 also provide an efficient way for the coil springs 32 to contact the terminal blades 34 . Similarly, and for the same purpose as the coil springs 32 , the lower spring 36 sits within a chimney or receptacle 48 . The lower spring 36 will also be held in place within the receptacle 48 , without needing an exterior force when the lower spring 36 is pointing downwards in a normal position. While FIG. 3 shows the two coil springs 32 and also the lower spring 36 being present at the same time, this is only for illustration purposes. While such an arrangement is feasible, normally, there will only be two springs, either one coil spring 32 and the lower spring 36 , or two coil springs 32 , used in the contactor 10 at one time. Likewise, the terminal blades 34 will only be present when a corresponding spring is located within a corresponding chimney. While any springs or other similar devices may be used, the headspring 24 , the coil springs 32 , and the lower springs 36 are preferably of the same shape and design, thereby easing assembly and inventory.
[0027] FIG. 3 also shows a steel housing 50 sitting on the bobbin 28 around the coil 30 (see FIG. 7 ). The plunger rod 22 goes through the center of the plunger 78 (not shown), in turn the bobbin 28 and is held in place by a plunger washer 52 . The bobbin 28 and the plunger rod 22 will be described in more detail with respect to FIG. 7 . A compression washer 54 sits below the bobbin 28 . The compression washer 54 is preferably a one-piece design that is either molded or cut from stock material. It preferably includes a recess so that it will not interfere with the chimney 48 located on the lower bobbin end 47 . The compression washer 54 is preferably made from a resilient, flexible material such as neoprene. A gasket 56 , preferably made of cork, rubber or a cork/rubber composite, sits between the housing 16 and the cover 18 . The cover 18 is secured to the housing unit 16 by a plurality of rivets 58 . While any fastening means may be used to secure the cover 18 to the housing unit 16 , it is preferred that the rivets or fastening means 58 are arranged in an evenly spaced circular arrangement for equal loading of the gasket 56 for more efficient sealing purposes.
[0028] FIG. 4 shows an interior bottom view of the housing unit 16 . At the center of the housing sits the well 60 that allows the headspring 24 (not shown) to be situated within the housing 16 . The well 60 provides a surrounding structure for the headspring 24 so that it will be properly biased against the plunger rod 22 (see FIG. 2 ) and will not slide around within the housing 16 . The housing 16 has a pair of longitudinally extending channels 62 , which correspond to the size and shape of the chimneys 48 (see FIGS. 2 and 3 ). The low current stud 14 is located in an end wall 61 of the housing 16 within the area defined by one of the longitudinally extending channels 62 . The high current studs 12 can be seen situated in the end wall 61 on either side of the well 60 . The mating effect of the chimneys 48 and the longitudinally extending channels 62 prevents the bobbin 28 (not shown) from rotating within the housing, which provides for an easier and more efficient assembly for locating the proper arrangement of the solenoid assembly and to further insure that the low current stud 14 will make contact with the coil spring 32 .
[0029] FIGS. 5 and 6 show views of the high current terminal or stud 12 . A ribbed area 64 and a lip 66 provide for a design that secures the stud 12 within the molded housing 16 (see FIG. 2 ). The ribbed area 64 restricts rotation of the stud when it is sealed within the end wall 61 of the housing 16 . Above the ribbed area 64 is a knurl feature 68 . When sealed within the end wall 61 , the knurled area 68 will be located externally of the contactor housing 16 . The knurl 68 assists in the mating of the stud 12 with an exterior wire or cable connector or other interconnecting hardware (not shown). A connected terminal wire or cable will be restrained from rotating by the knurl 68 during tightening of the nut (not shown). The stud 12 also has an end or contact pad 70 that is crowned. The crowned end 70 provides a more efficient mating surface for the contact disc 20 , which results in a more consistent and reliable current passing through the stud 12 .
[0030] An exploded view of the bobbin 28 and the plunger rod 22 is shown in FIG. 7 . As previously stated, the C-clip 40 holds the contact disc 20 and the seal spring 26 on the plunger rod 22 . The C-clip 40 allows the contact disc 20 and the plunger rod 22 to be mechanically connected to one another. It should be noted that any securing means, such as bolts, clasps, clips, pins, or other similar means, may be utilized in place of the C-clip 40 , provided the means do not interfere with the assembly process. The plunger rod 22 will pass through the center of a top flux washer 72 , the bobbin 28 , and a bottom flux washer 74 . The top flux washer 72 and the bottom flux washer 74 are separate structures from the bobbin flanges 47 of the bobbin 28 . The plunger rod 22 also passes through a plunger casing 78 and a pole piece 76 , both of which are situated within the center of the bobbin 28 . The plunger rod 22 is connected to the plunger washer 52 , which is located below the bottom flux washer 74 . The plunger rod 22 , the plunger casing 78 and the plunger washer 52 are designed as separate pieces and then staked or connected to one another. It should be noted that any securing means, such as threads, clasps, clips, pins, or other similar means, may be utilized in place of the staking process. While the pieces could be cut from raw material as a single piece, machining them as separate pieces is more cost effective, since there will be less scrap raw material. The plunger is also preferably of a geometry that is optimized for short stroke operating conditions, which will be used in shaping the solenoid force curve required for a predetermined level of performance. This is accomplished by allowing a larger diameter section of the plunger to operate outside the main coil assembly.
[0031] Still referring to FIG. 7 , the top flux washer 72 and the bottom flux washer 74 are designed with notches 80 that fit around a corresponding projection 47 a and chimney 48 . The notches 80 loosely fit around the projections 47 a and prevent the washers 72 and 74 from rotating separately of the bobbin 28 when assembled. The chimneys 48 , projections 47 a , bobbin flanges 47 , and the bobbin 28 are preferably molded from a single piece of plastic, but could be designed as separate pieces and fastened together. The wound coil 30 sits on the bobbin 28 and is connected at its respective ends to the respective terminal blades 34 . The coil 30 is wrapped with a protective insulating layer 82 , which sits between the coil 30 and the steel housing 50 . The elements shown in FIG. 7 are assembled as an independent subassembly, which allows the elements to be assembled and visually verified for accuracy prior to being placed within the housing 16 (not shown). Such an arrangement also allows for the critical components to be assembled outside of the housing unit 16 .
[0032] As shown in FIG. 7 , the steel housing 50 is designed of two halves, 50 a and 50 b . The halves 50 a and 50 b are preferably substantially identical sections assembled symmetrically around the bobbin 28 . Such an arrangement provides for an efficient flux path for the coil 30 , since no gap is needed in the housing 50 to clear the bobbin 28 during assembly. Furthermore, the housing 50 has an advantage over a rolled, single section housing in that the housing 50 does not have to be compressed to be fit properly around the bobbin 28 and to also fit within the housing unit 16 . The halves 50 a and 50 b , along with the bobbin 28 , may be easily slipped into the housing unit 16 without any additional reshaping or reforming of the steel housing 50 , which is normally necessary with single piece designs. While the invention would work with a single section housing unit, it is advantageous to have the arrangement described above.
[0033] FIG. 8 is a close-up exploded view of the projection 47 a , the chimney 48 and the terminal blade or coupling means 34 . A slot 84 , which is located within the projection 47 a , receives the terminal blade 34 . The slot 84 extends inwardly past the area of the projection where the chimney 48 is located, allowing the terminal blade 34 to be in solid contact with one of coil springs 32 / 36 (not shown). Preferably, the end of the coil 30 is attached to the terminal blade 34 by welding, soldering or other attachment means that will allow a current to pass from the coil 30 to the terminal blade 34 . The arrangement of the projection 47 a , the chimney 48 , and the blade 34 allows for easy assembly and connection of the coil 30 to the blade 34 . As previously stated, the projections 47 a and the chimneys 48 are preferably molded as one piece, but it is possible that they could be molded individually and then later joined together. Likewise, the chimneys 48 are shown to be cylindrical so that they are in mating relationship with the coil springs 32 / 36 . However, it is within the realm of this invention for the chimneys 48 to be of any shape that will provide a mating relationship with the springs 32 and 36 , which may also be of other shapes and designs than the currently shown springs.
[0034] After the bobbin 28 , the projection 47 a , and the chimney 48 are assembled or formed, the blade 34 may then be slid into the slot 84 , preferably extending the entire length of the slot with a small lip 85 located outside of the slot 84 . The lip 85 will provide an area for the end of the coil 30 to be secured to the blade 34 . Because the lip 85 is located outside of the bobbin 28 , less manipulation is required in securing the separate parts, which results in an easier and more efficient assembly process.
[0035] FIG. 9 is a side view of a contactor 10 showing the solenoid being connected to two low current studs 14 . In this arrangement, two coil springs 32 are present. Each spring 32 is connected to one of the low current studs 14 , with one stud 14 connected to the positive polarity of a voltage source and the other stud 14 connected to the negative polarity of a voltage source or chassis ground. The low current studs 14 include a post 0 . 86 , which the coil spring 32 will mate around to further insure a secure contact between the spring 32 and the stud 14 . As current enters the solenoid through the low current stud 14 , it flows through the coil springs 32 , the terminal blade 34 , and into the coil 30 . The result is the contact disc 20 is forced upward from the magnetic flux produced from the coil 30 , and the disc 20 makes contact with each contact pad 70 , thereby providing a bridge for the high current terminals 12 . The lower spring 36 is not present in this arrangement. Also, there is no terminal blade 34 located in the chimney 48 that would normally house the lower spring 36 .
[0036] FIG. 10 is a side view of a contactor 10 having a single low current stud 14 mounted in the housing 16 . This single stud 14 receives the input current. The coil spring 32 is connected to the stud 14 and the post 86 and makes a connection to the upper terminal blade 34 . Power is transferred across the high current terminals 12 in the same fashion as in FIG. 9 . However, in this arrangement, the lower spring 36 is present and connected to the lower terminal blade 34 . The lower spring 36 is in contact with the cover 18 , which provides one of the coil connection paths, usually via chassis ground. The second coil spring 32 that was present in FIG. 9 is not present, and the respective projection 47 a for the second coil spring 32 does not have the terminal blade 34 connected to it, either.
[0037] The design of the housing unit 16 is such that the end wall 61 (see FIGS. 1 and 2 ) is portrayed as being opposite of where the cover 18 is located. However, the end wall 61 should be construed broadly as an area of the housing unit 16 where the terminals 12 and 14 are located. For instance, if the terminals were located in the cylindrical portion of the housing 16 , that should also be considered as the end wall 61 . Likewise, the longitudinally extending channels 62 , terminals 12 , and terminals 14 , are shown to be diametrically opposed. While such a design may be advantageous for manufacturing and design purposes, it is not critical for the present invention. Provided there is sufficient insulation between the different electrical contacts, any arrangement will be within the scope of the present invention.
[0038] The foregoing is considered as illustrative only of the principles of the invention. Furthermore, 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. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
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A direct current contactor having at least one low current terminal and at least two high current terminals is disclosed. The low current terminal is connected to a spring, which is nested in a chimney-shaped receptacle, where it is coupled to the contactor's coil. The chimney shaped receptacle also has a slot that receives a terminal blade that electrically connects the spring to the coil. The housing of the solenoid is designed with longitudinally extending channels that receive the receptacles, which prevents the assembly from rotating within the housing unit. Each terminal is provided with ribbed and knurled areas to restrict rotation of the terminal in the housing and the mating connection while tightening.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from German Patent Application No. 10 2006 014 419.8 dated Mar. 27, 2006, the entire disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates to an apparatus on a spinning preparation machine, especially a flat card, roller card or the like, for adjusting the carding clearance.
[0003] It is known for a clothed roller, for example a cylinder, to have a cylindrical peripheral surface facing and spaced radially from a cladding, wherein between the peripheral surface of the roller and a part of the cladding there is a carding region with a carding clearance between clothings facing each other where carding work is performed and carding heat is generated, and in which heat leads to an alteration across the width of the machine in the contour of at least one of the components facing each other.
[0004] The distances between the cylinder clothing and surfaces (countersurfaces) facing them are of considerable importance in respect of engineering and fibre technology. The carding result, namely, degree of cleaning, nep formation and fibre shortening, is substantially dependent on the carding gap, that is, the clearance between the cylinder clothing and the clothings of the revolving and stationary flats. The air flow around the cylinder and the dissipation of heat are likewise dependent on the clearance between the cylinder clothing and facing clothed or also unclothed surfaces, for example, separation blades or cover elements. The clearances are subject to different, in some cases counteracting, influences. The wearing down of clothings facing each other results in an enlargement of the carding gap, which is associated with an increase in the number of neps and a reduction in fibre shortening. An increase in the speed of revolution of the cylinder, e.g. to enhance the cleaning action, results in an expansion of the cylinder inclusive of the clothing owing to the centrifugal force, and hence in a reduction in the carding gap. The cylinder expands also when processing large quantities of fibre and certain types of fibres, e.g. synthetic fibres, owing to a temperature increase that is greater than in the remainder of the machine surrounding the cylinder, so that the clearances also decrease for that reason. The machine elements lying radially opposite the cylinder, for example, stationary carding segments and/or separation blades, also expand.
[0005] The carding gap is influenced particularly by the machine settings on the one hand and the condition of the clothing on the other hand. The most important carding gap of a revolving flat card is located in the main carding zone, i.e. between the cylinder and the revolving flat assembly. At least one clothing, which delimits the operating clearance of the carding zone generally, is in motion. In order to increase the output of the card, efforts are made to select the operating speed of rotation and the operating speed of the moving elements as high as the technology of fibre processing will allow. The operating clearance is located in the radial direction (starting from the axis of rotation) of the cylinder.
[0006] In carding, ever larger amounts of fibre material are being processed per unit of time, which involves higher speeds of the work elements and higher installed capacities. With the work surface remaining constant, increasing throughput of fibre material (output) leads to greater generation of heat owing to the mechanical work. At the same time, however, the technological carding result (sliver uniformity, degree of cleaning, reduction of neps etc.) is continually being improved, which requires more active surfaces engaged in carding, and settings of these active surfaces closer to the cylinder (drum). The proportion of synthetic fibres to be processed is continually increasing, with more heat, compared with cotton, being produced as a result of friction from contact with the active surfaces of the machine. The work elements of high-performance cards are today fully enclosed all round in order to comply with the high safety standards, prevent particle emission into the spinning works environment and minimise the need for maintenance of the machines. Gratings or even open, material-guiding surfaces that allow exchange of air belong to the past. The circumstances described appreciably increase the input of heat into the machine, whereas there is a marked decrease in the discharge of heat by means of convection. The resulting increased heating of high-performance cards leads to greater thermoelastic deformations, which have an influence on the set spacings of the active surfaces owing to the uneven distribution of the temperature field: the distances between cylinder and card top, doffer, fixed card tops and separation points with blades decrease. In an extreme case, the gap set between the active surfaces can close up completely as a result of thermal expansion, so that components moving relative to one another collide. The high-performance card concerned then suffers considerable damage. Moreover, in particular the generation of heat in the working region of the card can lead to different thermal expansions when the temperature differences between components are too large.
[0007] To reduce or avoid the risk of collisions, in practical operation the carding gap between clothings facing each other is set to be relatively wide, i.e. a certain safety clearance exists. A large carding gap, however, leads to undesirable nep formation in the card sliver. In contrast, an optimum, especially narrow size is desirable, whereby the nep count in the card sliver is substantially reduced. Displacement relative to one another of the elements facing each other leads to a change in the clearance (carding gap) across the overall width of the machine.
[0008] The carding gap has a significant influence on the carding result. That is to say, a carding gap that is as uniformly narrow as possible across the working width produces optimum results. For the cylinder, it follows from this that the integrity of its cylindrical shape is of crucial importance. With reference to the cylinder, there is a further problem in that it is unevenly heated across the working width as a result of varying material coverage and fluctuations in the gap as a consequence of manufacturing tolerances. In addition, heat is dissipated more at the edge regions than in the middle, so that heat accumulates in the middle. This leads to a temperature gradient from the middle of the working width to the edges. The different thermal expansion brought about by this causes a convexly shaped bulging (camber) of the cylinder and thus impairs the carding gap. The carding result is consequently adversely affected. Since the cylinder is a counterpart for all carding and separation points, this loss of quality occurs at all points. In the case of the elements facing each other, e.g. the cylinder and carding elements, generation of heat during operation causes a marked expansion in the middle that reduces towards the edge regions. The disadvantage is that the carding gap is thus uneven across the width of the card and in the middle region there is a risk of collision between the components.
[0009] In a known apparatus (WO 2004/106602 A), in the case of a roller and a work element that face each other at least one contour is made concave (hollow) in the course of manufacture. The extent of the hollow machining corresponds to the expected thermal expansion during an intended output. The correction is designed for an ideal output amount. In particular, allowances are made for the expected expansions such that no re-adjustment of the spacing of the individual components with respect to one another is needed. One disadvantage is that presetting of a specific concave contour allows only a single alteration in the curved shape of the elements during operation. Adaptation to changed processing conditions, especially a change in the fibre material volume and quality, is therefore not possible. In addition, it is inconvenient that the inherent heat of the elements in operation, which causes the expansions, is constant, so that the curved form is correspondingly constant and cannot be adapted to changed production conditions.
SUMMARY OF THE INVENTION
[0010] It is an aim of the invention to produce an apparatus of the kind mentioned at the beginning, which avoids or mitigates the said disadvantages, and which in particular in a simple manner allows a uniform carding gap (carding clearance), preferably under different production and processing conditions.
[0011] The invention provides an apparatus on a spinning preparation machine for adjusting a carding clearance, in which a clothed roller is opposed to one or more machine elements, defining between the clothing of the clothed roller and said one or more machine elements an adjustable carding clearance where, in operation, carding is effected and carding heat is generated, and the contour of at least one of the clothed roller and at least one said opposed element is alterable in response to heat, wherein the apparatus comprises a device for input of energy to at least one of said roller and at least one said opposed element, in which the carding clearance can be made smaller by the input of energy to said at least one of said roller and at least one said opposed element and/or can be enlarged by throttling of said input of energy.
[0012] Because the energy, preferably heat, is generated by an external device, that is, a device that is present expressly for the purpose of inputting energy to one of the components defining the carding gap, preferably a heater apparatus, this enables an influence independent of the constant carding heat to be exerted on the contour of at least one of the components facing each other. In this simple manner the contour can be specifically altered and adjusted during operation so that the carding gap is constant across the width. A particular advantage is that even in the case of different production and processing conditions, the carding clearance is correspondingly adjustable to accommodate them. The temperature gradient is neatly minimised across the working width and the thermal expansion is thereby rendered uniform.
[0013] The roller may, for example, be the cylinder of a flat card or roller card. The opposed element may be a carding element, for example a stationary carding element, or may be a separating blade, a guide element, or a further clothed roller. There may be one or more further opposed elements, which may comprise one or more of a carding element, a separating blade, a guide element and a clothed roller, for example, a doffer or a licker-in.
[0014] If desired, the contour of just one component may be alterable. In other embodiments, the contour of both the roller and an opposed component or opposed components may be alterable. Advantageously, there is supplied, as said energy, heat.
[0015] At least one component may be heated by energy input. Advantageously, at least one component is heated by induction heat in the component. Advantageously, at least one contour is alterable in operation, and preferably the at least one contour is adjustable in operation. In preferred arrangements, in which the carding clearance alters in operation, the carding clearance is adjustable in operation.
[0016] In certain embodiments, no energy or heat input is effected in the middle region of the at least one component. Advantageously, at least one component is heatable in zones. Preferably, the surface of the cylinder is heatable in zones. Advantageously, a heating device is associated with the at least one component. The heating device may be associated with the surface (peripheral surface) of the roller, e.g. cylinder. In certain embodiments, the heating device is externally associated with the surface (peripheral surface) of the roller. In further embodiments, the heating device is associated with the roller in the inner space of the surface (inner peripheral surface), for example, ribs or the like for increasing the heat absorption may be present on the inner peripheral surface.
[0017] Where a heating device is present the heat output of the heating device is adjustable across the working width. The heating device may be divided into several zones across the working width. The heating device may be so arranged that different quantities of heat are introducible into the roller surface. There may be used, for example, an electrical heating device or an inductive heating device. Where present, the heating device may be arranged in a carrier arrangement. The carrier arrangement may be a profiled element. The heating device may be integrated in an aluminium profiled member. Advantageously, the heating device is capable of heating the edge regions of the at least one component, e.g. the roller, in zones. In some embodiments, the heating device is connected to an electrical open loop and closed loop control device.
[0018] The roller is advantageously a carding cylinder consisting of a ferromagnetic material, e.g. steel.
[0019] If desired, the energy input can be effected across the entire width of the at least one component. In certain preferred embodiments comprising an inductive heating device, the apparatus preferably comprises a controllable electrical power circuit for changing the heat generated by inductive energy input.
[0020] In many embodiments, an external device is usable for generation or input of energy.
[0021] The carrier arrangement for the heating device or other external energy-input device may be mounted, for example, on the extension bends of a flat card or roller card, or on the side panels of a flat card.
[0022] The apparatus is, in certain advantageous embodiments, constructed to be interchangeable in modular manner with one or more other components of the machine. For example, a plurality of covering or work elements (modules) of the same dimension are present at the roller, the dimensions of the carrier arrangement over the length and width being arranged to be the same or substantially the same as those of a covering element or work element (module).
[0023] In certain embodiments, a control means is provided, in order to control the energy input after the warm-up phase to adjust a narrow carding gap across the width. Where provided the control means may, if desired, be arranged, after the machine reaches a stable operating state, to control the energy input for renewed correction of the carding clearance, for example, in order to make allowances for wear and/or grinding processes.
[0024] The invention also provides an apparatus on a spinning preparation machine, especially a flat card, roller card or the like, for adjusting the carding clearance, in which a clothed roller, for example a cylinder, has a cylindrical peripheral surface facing and spaced radially from a cladding, wherein between the peripheral surface of the roller and a part of the cladding there is a carding region with a carding clearance between clothings facing each other where carding work is performed and carding heat is generated, and in which heat leads to an alteration across the width of the machine in the contour of at least one of the components facing each other, wherein the carding clearance is capable of being made smaller by external energy input to at least one of the components facing each other and/or is capable of being enlarged by throttling the energy input and the energy input and/or throttling of the energy input increases towards the edge regions of the components.
[0025] Furthermore, the invention provides an apparatus on a spinning preparation machine, especially a flat card, roller card or the like, for adjusting the carding clearance, in which a clothed roller, for example a cylinder, has a cylindrical peripheral surface and a cladding facing and spaced therefrom, wherein between the peripheral surface of the roller and a part of the cladding there is a carding region with a carding clearance between clothings facing each other where carding work is performed and carding heat is generated, and in which heat results in an expansion across the width of the machine of at least one of the components facing each other, wherein the carding clearance can be made smaller by external energy input to at least one of the components facing each other and/or is can be enlarged by throttling the energy input and the energy input and/or throttling of the energy input is effected uniformly across the width.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a schematic side view of a flat card with a heating device according to the invention;
[0027] FIG. 2 shows a cutout from a side panel with an extension bend section, on which a heating device according to the invention and a stationary carding element are mounted;
[0028] FIG. 3 is a plan view of a partial section through the cylinder of the flat card of FIG. 1 and of the supporting profile arranged across the working width with heating units in the edge regions of the cylinder;
[0029] FIG. 4 a shows the convexly curved casing of a carding cylinder across the working width with a convexly curved contour resulting from carding heat without external energy input;
[0030] FIG. 4 b shows the flat (straight) casing of the cylinder of FIG. 4 a with a flat (straight) contour after external energy input;
[0031] FIG. 5 shows schematically a block circuit diagram with an open loop and closed loop control device to which four controllable heating devices and four temperature sensors of a device according to the invention are connected; and
[0032] FIG. 6 shows a further embodiment in which the carding cylinder is generally as in FIG. 3 , but in which heating devices are arranged across the entire working width, in particular for the uniform alteration of the carding gap across the working width.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0033] With reference to FIG. 1 a card, for example, the card TC 03 made by Trützschler GmbH & Co. KG of Monchengladbach, Germany, has a feed roller 1 , feed table 2 , licker-ins 3 a , 3 b , 3 c , cylinder 4 , doffer 5 , stripping roller 6 , squeezing rollers 7 , 8 , web-guide element 9 , web funnel 10 , take-off rollers 11 , 12 , revolving flat 13 with flat guide rollers 13 a , 13 b and flat bars 14 , can 15 and can coiler 16 . The directions of rotation of the rollers are shown by respective curved arrows. The letter M denotes the midpoint (axis) of the cylinder 4 . The reference numeral 4 a denotes the clothing and reference numeral 4 b denotes the direction of rotation of the cylinder 4 . The letter B denotes the direction of rotation of the revolving flat 13 in the carding position and the letter C denotes the reverse transport direction of the flat bars 14 . Stationary cover and work elements, e.g. stationary carding elements 17 I , are arranged between the licker-in 3 c and the rear flat guide roller 13 a and stationary cover and work elements, e.g. stationary carding elements 17 II , are arranged between the front licker-in 3 a and the doffer 5 . The letter A denotes the work direction. The curved arrows drawn in the rollers denote the direction of rotation of the rollers. The numeral 2 denotes a heating device according to the invention.
[0034] In the illustrative embodiment shown in FIG. 2 , on each side of the card an approximately semi-circular, rigid side panel 18 a , 18 b (see FIG. 3 ) is secured laterally to the machine frame (not shown); mounted, e.g. by screws, on the outside of the side panel, concentrically in the region of the periphery thereof, there is a curved bearing element 19 a , 19 b (extension bend)—see FIG. 3 —, which has a convex outer surface 19 I as its bearing surface and an underside 19 II . At both ends the carding element 17 I has bearing surfaces, which lie on the convex outer surface 19 I of the bearing element 19 . Mounted on the underside of the carding segment 17 I are carding elements 20 a , 20 b with carding clothings 20 a I , 20 b I . The reference numeral 21 denotes the tip circle of the clothings. The cylinder 4 has on its periphery a cylinder clothing 4 a , for example, a saw tooth clothing. The reference numeral 22 denotes the tip circle of the cylinder clothing 4 a . The distance between the tip circle 21 and the tip circle 22 is denoted by the letter a, and is, for example, 0.20 mm. The distance between the convex outer surface 19 I and the tip circle 22 is denoted by the letter b. The radius of the convex outer surface 19 I is denoted by r 1 and the radius of the tip circle 22 is denoted by r 2 . The radii r 1 and r 2 intersect at the mid-point M (see FIG. 1 ) of the cylinder 4 . The carding segment 17 I shown in FIG. 2 consists of a support 23 and two carding elements 20 a , 20 b , which are arranged in succession in the direction of rotation (arrow 4 b ) of the cylinder 4 , the clothings 20 a I , 20 b I of the carding elements 20 a , 20 b and the clothing 4 a of the cylinder 4 lying facing each other.
[0035] The heating device 26 , viewed in the direction of rotation 4 b of the cylinder 4 , is arranged next to the carding segment 17 I . The heating device 26 comprises, as housing 29 , a hollow aluminium profiled member, in the inner space of which an inductive heating apparatus 27 is arranged. The heating apparatus 27 comprises an induction coil 27 I , which is connected to an alternating current supply 28 . The widths of the elements carding segment 17 I and heating device 26 mounted on the extension bends 19 a , 19 b is denoted by f 1 and f 2 respectively.
[0036] FIG. 3 shows a part of the cylinder 4 with a cylindrical surface 4 f of the casing 4 e and cylinder end discs 4 c , 4 d (radial supporting elements). The surface 4 f is provided with a clothing 4 a , which in this example is in the form of wire with saw-teeth. The saw-tooth wire is drawn onto the cylinder 4 , i.e. is wound round in tightly adjacent turns between side flanges (not shown) in order to form a cylindrical work surface equipped with tips. Fibres are intended to be processed as evenly as possible on the work surface (clothing). The carding work is carried out between the clothings 20 a I , 20 b I and 4 a located facing each other. It is influenced substantially by the position of the one clothing with respect to the other and by the clothing spacing a between the tips of the teeth of the two clothings 20 a , 20 b , and 4 a . The working width of the cylinder 4 is a determining factor for all other work elements of the card, especially for the revolving flats 14 or stationary flats 17 I , 17 II ( FIG. 1 ) which, together with the cylinder 4 , card the fibres evenly across the entire working width. In order to be able to perform even carding work across the entire working width, the settings of the work elements (including those of additional elements) across this working width must be maintained. The cylinder 4 itself, however, can be deformed as a result of drawing-on the clothing wire, by centrifugal force or by the heat generated by the carding process. The shaft journals 24 a , 24 b of the cylinder 4 are mounted in bearings 25 a , 25 b , which are attached to the stationary machine frame, not shown. The diameter, for example 1250 mm, of the cylindrical top surface 4 f , that is to say twice the radius r 1 , is an important dimension of the machine. The side panels 18 a , 18 b are secured to the two machine frames (not shown). The extension bends 19 a , 19 b are secured to the side panels 18 a , 18 b respectively. The circumferential speed of the cylinder 4 is, for example, 35 m/sec. The two end regions of the housing 29 of the heating device 26 , which extends across the width c of the cylinder 4 , are fastened to the extension bends 19 a , 19 b . Inside the housing 29 there are four inductive heating devices 27 , two heating devices 27 1 , 27 2 lying opposite one edge region 4 e I of the casing 4 e of the cylinder 4 and two further heating devices 27 6 , 27 7 lying opposite the other edge region 4 e , of the casing 4 e of the cylinder 4 —in each case spaced therefrom. The heating devices 27 1 , 27 2 , 27 6 , 27 7 are arranged side by side across the width c in the axial direction of the cylinder 4 .
[0037] FIG. 4 a shows—drawn to an exaggerated extent—the convexly curved contour of the casing 4 e that has bulged owing to thermal expansion during operation. In relation to the middle region 4 e III , in which the expansion is greatest, the two edge regions 4 e I and 4 e II drop away towards both sides, especially on account of the greater heat dissipation towards the sides. Because the heating devices 27 1 , 27 2 and 27 6 , 27 7 (see FIG. 3 ) heat up the edge regions 4 e I and 4 e II , the edge regions 4 e I , 4 e II expand, so that, as shown in FIG. 4 b , the surface of the casing 4 e is even and flat across the width c and the diameters r 1 and r 3 (see FIG. 3 ) of the casing 4 e of the cylinder 4 are the same at all points across the width.
[0038] In a further embodiment shown in FIG. 5 (only one side of the cylinder 4 is illustrated), the heating devices 27 1 , 27 2 and 27 6 , 27 7 are connected to an electrical open loop and closed loop control device 31 , which is furthermore connected to four temperature sensors 30 1 , 30 2 and 30 6 , 30 7 . The temperature sensors 30 are arranged in a heat-permeable housing 32 , which extends across the width c of the cylinder 4 and is fixed to the extension bends 19 a , 19 b . The temperature sensors 30 1 , 30 2 are arranged radially spaced from and facing the edge region 4 e I and the temperature sensors 30 6 , 30 7 (not shown) are arranged radially spaced from and facing the edge region 4 e II . In this way the heat output of the heating devices 27 1 , 27 2 and 27 6 , 27 7 in the edge regions 4 e I and 4 e II can be adjusted to increase outwards.
[0039] In the embodiment of FIG. 6 , seven inductive heating units 27 1 to 27 7 , which are connected to the open loop and closed loop control device 31 (see FIG. 5 ), are arranged side by side across the entire width c of the cylinder 4 . The heat output of the heating units 27 1 to 27 7 , independently of or in addition to the embodiment illustrated in FIGS. 3 and 5 , can be effected uniformly across the width c of the machine, so that the carding gap a (see FIG. 2 ) is uniformly altered across the width c. The carding nip a can be made smaller by energy input and enlarged by throttling the energy input. In this way it is possible, for example, to adjust a desired narrow carding nip a.
[0040] The cylinder surface is advantageously heated in zones. The temperature gradient across the working width is minimised by the roller heating unit and hence thermal expansion is evened out. The heating unit is divided into several zones across the working width so that different quantities of heat can be introduced (induced) in the roller surface. Heating of the cylinder is effected especially advantageously by means of an inductive heating unit. Only ferromagnetic materials are heated by this means and the fibre material is not affected. It is furthermore advantageous if the heating unit is integrated in an aluminium profile, without this itself being heated up.
[0041] The energy input is effected by an external device, namely by way of the induction coils 27 I of the heating units 27 , from outside the cylinder 4 , and the induction heat is generated in the casing 4 e of steel and the end discs 4 c , 4 d of the cylinder 4 . Because energy, but not heat, is supplied for heat generation, the fibre material situated on the clothing 4 a is not affected.
[0042] The aluminium profile 29 is not heated by the inductive heating unit 27 .
[0043] The invention was explained using the example of energy input to the cylinder 4 . Similarly, the invention can be applied to energy input to a covering and/or a work element lying radially opposite the cylinder 4 , or to the energy input to both the cylinder 4 and to a covering and/or work element.
[0044] Although the foregoing invention has been described in detail by way of illustration and example for purposes of understanding, it will be obvious that changes and modifications may be practised within the scope of the appended claims.
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An apparatus is provided on a spinning preparation machine for adjusting the carding clearance. A clothed roller has a cylindrical peripheral surface and a cladding facing and spaced therefrom, wherein between the peripheral surface of the roller and a part of the cladding there is a carding region with a carding clearance where carding work is performed and carding heat is generated, heat leading to an alteration across the width of the machine in the contour of at least one of the components lying opposite each other. In order in simple manner to allow a uniform carding clearance under different production and processing conditions, the carding clearance can be made smaller by external energy input to at least one of the components facing each other and/or can be enlarged by throttling the energy input and the energy input.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This Divisional Patent Application claims the priority benefit of U.S. Non-Provisional patent application Ser. No. 12/702,887, filed Feb. 9, 2010, and Provisional Patent Application Ser. No. 61/151,122, filed Feb. 9, 2009, the entire scope and content of which are hereby incorporated herein by reference.
BACKGROUND
[0002] The present invention in general relates to fencing and railing systems, and in particular relates to connectors for fencing and railing systems.
SUMMARY
[0003] Briefly described, in a first example embodiment the present invention relates to a fencing/railing assembly adapted to be positioned between a pair of posts and mounted thereto. The assembly includes a plurality of pickets, a plurality of rails extending transverse to the pickets, and a connection between the pickets and the rails. The picket/rail connection is slidably mounted to the rail and pivotally connected to the picket to permit a sliding, pivotal motion. The sliding, pivotal connection allows the pickets to be oriented at greater angles relative to the rails (i.e., it allows the assembly to rack to a greater degree, thereby allowing the fencing/raining to follow more steeply changing terrain or contours).
[0004] In one preferred form, the fencing/railing assembly includes one or more elongated connector strips that are each concealed by the rail and that each span a corresponding set of multiple adjacent pickets. In another preferred form, the fencing/railing assembly includes a plurality of shorter connectors, one for each picket/rail connection.
[0005] The connectors, be they shorter individual-picket connectors or longer multi-picket connector strips, can include small projections (e.g., bosses) that extend from one surface thereof and engage holes (e.g., recesses) formed in the pickets. Advantageously, this provides a fastener-less but still pivotal connection. Preferably, the rails each have an inner profile that is sized and shaped to slidably retain or capture the connector between the rail and the picket, while permitting the connector strip to slide relative to the rail and be concealed by the rail during normal use. For example, the rail can have an inwardly extending shelf or ledge that slidingly supports the connector strip so that the connector strip slides atop the shelf.
[0006] The fencing/railing assembly, including the pickets, the rails, and the concealed connectors, can be made of extruded aluminum, plastic, or other materials. Also, the rails can be generally U-shaped and have picket openings formed in one portion thereof for receiving the pickets therethrough. Optionally, a leading, inner edge of the railing may be beveled or eased to facilitate slipping the rail over the connector during assembly.
[0007] In another aspect, the present invention relates to a pre-assembled fencing/railing assembly adapted to be positioned between a pair of posts and mounted thereto. The assembly includes the same components as those described above. But these components are pre-assembled at a factory or other assembling facility. And the assembly is shipped in this pre-assembled state, ready for installation, so this part of the assembly process is not done on-site in the field.
[0008] In yet another aspect, the present invention relates to a method of manufacturing a fencing/railing assembly to be positioned between a pair of posts and mounted thereto. One such example method includes the steps of: (a) providing a series of pickets each with one or more connector holes formed therein; (b) providing a connector strip with a series of connector bosses formed on at least one side thereof; (c) attaching the connector strip to the series of pickets by aligning and inserting the connector bosses into the connector holes formed in the pickets; (d) providing an at least three-sided rail (e.g., a generally U-shaped rail) with picket openings formed in an upper portion thereof; and (e) slipping the rail over the pickets and over the connector strip to secure the connector strip in place and conceal the connector strip.
[0009] These and other aspects, features and advantages of the invention will be understood with reference to the drawing figures and detailed description herein, and will be realized by means of the various elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following brief description of the drawings and detailed description of the invention are exemplary and explanatory of preferred embodiments of the invention, and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a front elevation view of a fencing/railing assembly according to a first example embodiment of the present invention.
[0011] FIG. 2 is a side view of the fencing/railing assembly of FIG. 1 .
[0012] FIG. 3 is a side sectional view of a portion of the fencing/railing assembly taken at line 3 - 3 of FIG. 1 .
[0013] FIG. 4 shows the left portion of the fencing/railing assembly of FIG. 3 , with hidden features shown in phantom lines.
[0014] FIG. 5 is a perspective, exploded view of the fencing/railing assembly of FIG. 1 , depicting the fencing/railing assembly being assembled.
[0015] FIGS. 6A-6E are front, top, back, side, and perspective views of a connector strip of the fencing/railing assembly of FIG. 1 .
[0016] FIGS. 7A-7B are schematic illustrations depicting the range of movement of a prior art picket-and-rail arrangement.
[0017] FIGS. 7C-7D are schematic illustrations depicting the range of movement of a picket-and-rail arrangement of the fencing/railing assembly of FIG. 1 .
[0018] FIG. 8 is a perspective view of a connector of a fencing/railing assembly according to a second example embodiment of the invention.
[0019] FIGS. 9-12 are plan, side, bottom, and perspective views of a connector boss strip of a fencing/railing assembly according to a third example embodiment of the invention.
[0020] FIG. 13 is a side view of a boss of the connector boss strip of FIG. 10 .
DETAILED DESCRIPTION
[0021] The present invention may be understood more readily by reference to the following detailed description taken in connection with the accompanying drawing figures, which form a part of this disclosure. It is to be understood that this invention is not limited to the specific devices, methods, conditions or parameters described and/or shown herein, and that the terminology used herein is for the purpose of describing particular embodiments by way of example only and is not intended to be limiting of the claimed invention. Any and all patents and other publications identified in this specification are incorporated by reference as though fully set forth herein.
[0022] Also, as used in the specification including the appended claims, the singular forms “a,” “an,” and “the” include the plural, and reference to a particular numerical value includes at least that particular value, unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” or “approximately” one particular value and/or to “about” or “approximately” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment.
[0023] Referring now in detail to the drawing figures, wherein like reference numerals represent like parts throughout the several views, FIGS. 1-6E and 7 C- 7 D show a fencing and/or railing assembly 10 according to a first example embodiment of the present invention. The railing assembly 10 is typically used to enclose yard spaces, decks, porches and the like.
[0024] Generally, the railing assembly 10 comprises a plurality of horizontally spaced pickets 20 and at least one support rail 30 . The pickets 20 are typically arranged generally vertically with the rail 30 transverse to them. In the depicted embodiment, the railing assembly comprises three support rails 30 a, 30 b, 30 c (as seen in FIG. 1 ) to space, align, and secure the pickets 20 and to provide for structural rigidity. Each picket 20 can also include an endcap 40 coupled to the top of the same (or formed in the top portion itself) to close off the top of the picket and/or to provide a decorative element to the railing assembly 10 . In example embodiments, the pickets 20 and railing 30 are formed from extruded aluminum, however, in alternative embodiments, the pickets and railing can be formed from solid aluminum, other metals and/or metal alloys, wood, rubber, plastic, and/or other materials known in the art. In example embodiments, the pickets 20 are hollow, square aluminum extrusions and the railings 30 roughly rectangular (but U-shaped) aluminum extrusions; however, in alternative embodiments, the pickets and railing can be formed in different shapes.
[0025] As seen in FIGS. 3 and 4 , the rails 30 can have a substantially “U” shaped cross-section and, in use, are generally oriented open-side-down such that the “bottom” of the “U” forms the top of the rail 30 . In alternative embodiments, the rails 30 can have a substantially “J” shaped cross-section or rectangular-shaped cross-section. In still other embodiments, the rails 30 can include other cross-section shapes as desired. The top wall of the rail 30 includes a series of horizontally spaced picket openings 39 through which the pickets extend. In depicted example embodiments the rail 30 is shown having a decorative bulge 38 on the exterior surface of the rail, however, in alternative example embodiments other exterior shapes can be utilized as desired.
[0026] As shown in FIGS. 3 and 4 , the rails 30 include at least one concealed ledge or shelf 32 for supporting a connector or boss strip 34 (or alternatively referred to as a dimpled strip) thereon. The shelf or shelves 32 extend inwardly from the inner surface of one or both sidewalls of the rail 30 . Optionally, the lower leading edges of the shelf 32 (or another portion of the rail 30 ) can be chamfered, ramped, or beveled to facilitate a slight outward deflection and smooth movement over the boss strip 34 during assembly. Once in place, the boss strip 34 is securely held there by the shelf 32 with the boss strip supported by the shelf and secured in place between the shelf and the top wall of the rail 30 . The boss strip 34 is captured between the corresponding sidewall of the rail 30 and the picket 20 but permitted to slide horizontally between the two and along the rail atop the shelf 32 . Additionally, the connector strip 34 can be made of a metal, plastic, or any other suitable material.
[0027] In addition, the boss strip 34 includes at least one inwardly extending boss (e.g., a nub, pin, or other protruding structure) 36 that is received in a pivot or connector hole 22 (e.g., a recess, through-hole, or slotted channel) in one of the pickets 20 for rotatably coupling the boss strip to that picket (as will be described in greater detail below with reference to FIGS. 7C-7D ). In an alternative embodiment, the boss/nub extends outward from the picket and the pivot hole is formed in the connector strip (this is an “opposite” or “vice versa” arrangement of that described above). In another alternative embodiment, aligning pivot holes are formed in the connector strip and the picket, a pivot pin is provided, and the two ends of the pivot pin are inserted into the two pivot holes. In yet another alternative embodiment, the pivot hole is horizontally slotted to provide for additional sliding motion.
[0028] And in still another alternative embodiment, the connector/boss strip is eliminated, the pickets each include at least one horizontally slotted connector hole, and the rails each include at least one inwardly extending boss that is received into the slotted connector hole. In this embodiment, the pickets pivot about the boss and the boss slides along the slotted connector hole such that the rail/boss and picket slide too. The opposite or vice versa arrangement can alternatively be provided, with the boss on the pickets and the slots in the pickets. As no connector strips are provided, and the strips in the above-described embodiments provide structural support for the overall fence/railing assembly, the rails and/or pickets of this embodiment are designed with relatively greater strength (e.g., a stronger material and/or thicker walls).
[0029] Thus, the railings 30 each have an inner profile that is sized and shaped to retain the connector or boss strip 34 between the rail and the picket while permitting it to slide and pivot relative to the pickets. With this construction, a sliding, pivoting connection is obtained and also concealed. The connection is also achieved without the use of any threaded fasteners.
[0030] In use, the railing assembly 10 can be assembled as partially demonstrated in FIG. 5 . For example, the plurality of pickets 20 are first inserted into and extended through the picket openings 39 of the rails 30 . Next, the connector or boss strips 34 (better seen and understood by viewing FIGS. 6A-6E ) are coupled to pickets 20 by inserting the bosses/nubs 36 into the corresponding holes 22 formed in the pickets. Finally, the rails 30 are lowered (from the depicted positions of FIG. 5 ) vertically along the pickets 20 and over the boss strips 34 , where they are snapped into place by forcing each rail ledge or shelf 32 over the boss strip, for example, by the beveled or ramped leading edge riding over the strip and deflecting slightly thereby.
[0031] As shown in FIG. 5 , multiple connector boss strips 34 can be used with each rail in the railing assembly 10 , with each boss strip being long enough that it is coupled to a set of multiple of the pickets 20 . The set of pickets can include all of the pickets 20 in a fence/rail section (between posts) or only some of them. In the typical commercial embodiment depicted, each boss strip is long enough that it is coupled to approximately five pickets 20 , and thus it has five bosses/nubs 36 . This coordinates together the pivoting of all of the pickets 20 engaged by a connector strip 34 (those in the picket set) relative to the rail 30 and that connector strip 34 . For example, if a connector strip 34 were to be in engagement with five pickets 20 , movement of a single picket amongst the five pickets would result in the other four pickets moving in synchronization with the single picket that is originally moved. In addition, by spanning multiple pickets 20 , the connector strips 34 provide structural support for the overall fence/rail assembly 10 , so the pickets and/or rails 30 can be designed to provide less overall structural strength (e.g., with thinner walls and/or less-strong materials).
[0032] In alternative embodiments, longer or shorter boss strips 34 can be utilized as desired, such that each boss strip can accommodate less than five pickets or more than five pickets. In still other alternative embodiments, a relatively short, single boss strip or connector is used for each picket/rail connection. As seen in FIG. 8 , for example, a short boss or connector strip 134 according to a second example embodiment is so short that it doesn't span from one picket to another and it only includes a single boss/nub 136 .
[0033] In manufacturing the product, a simplified technique or method is accomplished. In an example method, a pre-assembled section of fencing/railing assembly is constructed and shipped for sale. This allows the sections to be assembled under factory conditions, rather than under field conditions, for maximum efficiency and quality control. The pre-assembled fencing/railing assembly includes a length of fencing/railing ready to be installed between a pair of posts or uprights. Thus, the user would install the pre-assembled section of fencing/railing between the posts in the field.
[0034] The manufacturing method for constructing the pre-assembled section can include the steps of:
[0035] (a) providing a series of pickets with connector holes formed therein;
[0036] (b) providing at least one connector strip with one or a series of connector bosses formed on at least one side thereof;
[0037] (c) attaching the connector strip to the one or series of pickets by aligning and inserting the connector bosses into the connector holes formed in the pickets;
[0038] (d) providing a rail with picket openings formed in an upper portion thereof and with at least one shelf formed on an inner surface thereof; and
[0039] (e) slipping the rail over the pickets (with the pickets extending through the picket openings) and over the connector strip to secure the connector strip in place on the shelf and conceal the connector strip.
[0000] This manufacturing method allows for easy and economical manufacture, as well as providing a consistently good manufacturing quality. Also, when the pre-assembled section of fencing/railing is assembled, the connector strip is not readily visible (it is concealed by the rail).
[0040] In addition to concealing the connection and being readily pre-assembled in a factory for later field-installation by a user, a fencing/railing assembly according to the present invention also adjusts to follow rising or falling terrain better than known fencing/railing. As demonstrated by comparing a known prior art railing assembly ( FIGS. 7A-7B ) to the present invention ( FIGS. 7C-7D ), it can be seen that the present invention is better able to pivot the pickets relative to the rails in comparison to known railing assemblies. For instance, known railing assemblies incorporate screws S and/or bolts to rotatably couple pickets P to rails R, as shown in FIGS. 7A-7B . Such couplings are time consuming to install and only allow for a limited range of rotation and little if any horizontal movement. In fact, the known railing assembly of FIGS. 7A-7B only allows the pickets to rotate about 15 degrees in either direction before being obstructed by the edge of the picket opening.
[0041] In stark contrast, the present invention utilizes a sliding pivotal connection between the pickets 20 and the rails 30 that is very easy and fast to install and allows for limited horizontal movement of the pickets 20 along the rails 30 . In particular, the connector boss strip 34 slides within the rail 30 in the transverse directions denoted by the arrows X when the pickets 20 are pivoted in the angular directions denoted by the arrows Y, thereby allowing the pivot point between the connector hole 22 of the picket and the rail to slide one way or the other, as shown in FIGS. 7C-7D . Because of this, the picket 20 is afforded a higher degree of rotation within the picket openings 39 of the rail, while the pickets and picket openings are the same size as in prior art systems. In typical commercial embodiments, utilizing the present invention permits the pickets 20 to rotate about the boss 36 at least 36 degrees (as compared to the known railing assembly's typical rotational limit of about 15 degrees), using a similar opening gap between the picket and the edge of the picket opening in the railing—the additional freedom of motion is not due to simply making the opening larger. The amount of rotation depicted in FIGS. 7C-7D is meant to be exemplary of the capabilities of the present invention and is in no way meant to limit the scope of the present invention.
[0042] The above-described embodiments can be provided pre-assembled, with the cost of the materials and assembly being about the same as the prior art systems unassembled. Alternatively, the above-described embodiments can be provided unassembled and assembled on-site in the field during installation.
[0043] FIGS. 9-13 show a connector or boss strip 234 of a fence/rail assembly according to a third example embodiment of the invention. The connector boss strip 234 can be used in fence/rail assemblies that are pre-assembled or field-assembled. In this embodiment, the connector boss strip 234 includes bosses 236 with ribs 250 that better secure the bosses into the connector holes of the pickets. This is particularly beneficial when used in fence/rail assemblies that are field-assembled. In addition, the connector boss strip 234 includes internal openings 252 that reduce the amount of material used without reducing the structural integrity of the connector strips. It will be understood that the dimensions shows in FIGS. 9-13 are representative of typical commercial embodiments and are not limiting of the invention; the connector boss strip 234 can be provided with other dimension ins larger or smaller sizes.
[0044] While the invention has been described with reference to preferred and example embodiments, it will be understood by those skilled in the art that a variety of modifications, additions and deletions are within the scope of the invention, as defined by the following claims.
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A fencing/railing assembly adapted to be positioned between a pair of posts and mounted thereto. The assembly includes a plurality of pickets, a plurality of rails extending transverse to the pickets, and one or more pivoting, sliding connectors for connecting a picket to a rail, with the sliding, pivotal connection concealed by the rail. The connector is slidably mounted to the rail and is pivotally connected to the picket. The sliding, pivotal connection allows the pickets to be oriented at greater angles relative to the rails (i.e. it allows the assembly to rack to a greater degree, thereby allowing the fencing/raining to following more-steeply changing terrain or contours). In one embodiment, an elongated connector strip is concealed by the rail and spans multiple pickets. In another embodiment, the assembly includes a plurality of shorter connectors, one for each picket/rail connection.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 11/117,952, filed Apr. 29, 2005, now abandoned, the specification of which is herein incorporated by reference.
The following commonly assigned U.S. patents are related to the present application and are incorporated herein by reference in their entirety: “High-Energy Capacitors for Implantable Defibrillators,” U.S. Pat. No. 6,556,863, filed Oct. 2, 1998, issued Apr. 29, 2003; “Flat Capacitor for an Implantable Medical Device,” U.S. Pat. No. 6,699,265, filed Nov. 3, 2000, issued Mar. 2, 2004. Additionally, the present application is related to the following commonly assigned U.S. Patent Publication which is incorporated herein by reference in its entirety: “Method and Apparatus for Single High Voltage Aluminum Capacitor Design,” Ser. No. 60/588,905, filed on Jul. 16, 2004. Further, the present application is related to the following commonly assigned U.S. Patent Application which is incorporated by reference in its entirety: “Batteries Including a Flat Plate Design,” U.S. patent application Ser. No. 10/360,551 filed Feb. 7, 2003, which claims the benefit under 35 U.S.C 119(e) of U.S. Provisional Application Ser. No. 60/437,537 filed Dec. 31, 2002.
TECHNICAL FIELD
This disclosure relates generally to batteries and capacitors, and more particularly, to method and apparatus for an implantable pulse generator with a stacked battery and capacitor.
BACKGROUND
There is an ever-increasing interest in making electronic devices physically smaller. Consequently, electrical components become more compact as technologies are improved. However, such advances in technology also bring about additional problems. One such problem involves efficient packaging of components.
Components such as batteries, capacitors, and various additional electronics are often packaged together in electrical devices. As such, there is a need in the art for improved packaging strategies. Improvement could be realized by an overall increase in the efficiency of component packaging in existing devices. But improved systems must be robust and adaptable to various manufacturing processes.
SUMMARY
The above-mentioned problems and others not expressly discussed herein are addressed by the present subject matter and will be understood by reading and studying this specification.
One embodiment of the present subject matter includes a method of stacking flat battery layers into a battery stack; positioning the battery stack in a battery case, the planar battery surface having a battery perimeter; stacking flat capacitor layers into a capacitor stack; positioning the capacitor stack in a capacitor case, the planar capacitor surface having a capacitor perimeter; disposing the flat battery case and the flat electrolytic capacitor case in stacked alignment in a housing for implantation such that the battery perimeter and the capacitor perimeter are substantially coextensive; and hermetically sealing the housing.
Additionally, one embodiment of the present subject matter includes a battery having a plurality of flat battery layers disposed in a battery case, the battery case having a planar battery surface which has a battery perimeter; and a capacitor including a plurality of flat capacitor layers disposed in a capacitor case, the capacitor case having a planar capacitor surface which has a capacitor perimeter, the capacitor stacked with the battery such that the planar battery surface and the planar capacitor surface are adjacent, with the capacitor perimeter and the battery perimeter substantially coextensive; and a hermetically sealed implantable housing having a first shell and a lid mated to the first shell at a first opening, the first opening sized for passage of the battery and the capacitor, wherein the battery and the capacitor are disposed in the hermetically sealed implantable housing.
One embodiment of the present subject matter includes an apparatus having a hermetically sealed implantable device housing having a lid mated to an opening; programmable pulse generation electronics disposed in the hermetically sealed implantable device housing, the programmable pulse generation electronics sized for passage through the opening; battery means for powering the programmable pulse generation electronics, the battery means sized for passage through the opening; and capacitor means electrically interconnected to the battery means, the capacitor means for powering the programmable pulse generation electronics and sized for passage through the opening.
This Summary is an overview of some of the teachings of the present application and not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details about the present subject matter are found in the detailed description and appended claims. Other aspects will be apparent to persons skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part thereof, each of which are not to be taken in a limiting sense. The scope of the present invention is defined by the appended claims and their legal equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a side view of a power source, according to one embodiment of the present subject matter.
FIG. 1B illustrates a partial cross section of a device housing, a battery, and a capacitor, according to one embodiment of the present subject matter.
FIG. 2 is a perspective view of a capacitor, according to one embodiment of the present subject matter.
FIG. 3 is a perspective view of a battery, according to one embodiment of the present subject matter.
FIG. 4 is a perspective view of a battery and a capacitor, according to one embodiment of the present subject matter.
FIG. 5 is a method for constructing a battery and capacitor power source, according to one embodiment of the present subject matter.
DETAILED DESCRIPTION
The following detailed description of the present subject matter refers to subject matter in the accompanying drawings which show, by way of illustration, specific aspects and embodiments in which the present subject matter may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present subject matter. References to “an”, “one”, or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate more than one embodiment. The following detailed description is demonstrative and not to be taken in a limiting sense. The scope of the present subject matter is defined by the appended claims, along with the full scope of legal equivalents to which such claims are entitled.
Implantable medical devices are now in wide use for treating a variety of diseases. Cardiac rhythm management devices, as well as other types of implantable medical devices, are powered by a battery and a capacitor contained within the housing of the device. The size and shape of a battery which supplies sufficient power to operate the device is one factor which affects how small and physiologically shaped the housing of the device can be made. This is true for the capacitor as well. The present disclosure relates to a battery and capacitor and method for their construction, each suitable for use in an electronic device. Various embodiments are adapted for use in an implantable medical device. Overall, the present subject matter affords designers more freedom in packaging electronic device components into a housing.
FIG. 1A is a side view of a power source 100 , according to one embodiment of the present subject matter. In various embodiments, an example battery 102 includes a contour 116 , which allows for positioning the battery 102 in various devices. For example, in various embodiments, battery 102 is shaped for placement in device adapted for chronic implantation. Additionally, in various embodiments, the battery 102 includes a feedthrough port 108 , which is adapted for passage of one or more conductors. In various embodiments, the conductors at the feedthrough port 108 are connected to the battery anode. The battery additionally includes a feedthrough port 110 which, in various embodiments, is connected to the battery cathode. In some embodiments, a single feedthrough port is used instead of two feedthrough ports. Other embodiments include one or more feedthrough ports and a backfill port.
In various embodiments, the example capacitor 104 includes a contour 118 , which allows for positioning the capacitor 104 in various devices. For example, in various embodiments, capacitor 104 is shaped for placement in a device adapted for chronic implantation. Additionally, in various embodiments, the capacitor 104 includes a feedthrough port 112 , which is adapted for passage of one or more conductors. In various embodiments, the conductors at the feedthrough port 112 comprise a portion of the anode of the capacitor. The capacitor additionally includes a feedthrough port 114 which, in various embodiments, is connected to the battery cathode. In some embodiments, a single feedthrough port is used instead of two feedthrough ports. Other embodiments include one or more feedthrough ports and a backfill port.
In various embodiments, a device housing into which a battery and capacitor may be disposed has an interior. In some of these embodiments, the device interior has a first major interior face and a second major interior face. Battery and capacitor combinations can be shaped to mate to these faces. For example, in one embodiment, a battery face 120 is adapted for abutting an interior face of a housing. In some embodiments, the housing and the battery face 120 are separated from a housing by an insulator. The capacitor includes a face 122 which also is adapted for abutting an interior surface of a housing. Sidewall 402 and sidewall 404 are adapted for placement adjacent additional device components, in various embodiments.
Various embodiments maintain a continuous surface from sidewall 402 to sidewall 404 . In various embodiments, the seam 106 defined by the adjacent battery 102 and capacitor 104 extends along a continuous surface. Thus, in various embodiments, the combined capacitor and battery are adapted for space efficient placement in a housing. In various embodiments, the housing is only marginally larger than the combined capacitor and battery so that the housing may accommodate those components. As such, various embodiments enable packaging additional devices in the housing adjacent the battery capacitor combination.
Battery 102 has a thickness T B , in various embodiments. In various embodiments, the thickness is measured orthogonally, extending between interface 106 and surface 120 . Additionally, capacitor 104 has a thickness T C , in various embodiments. The thickness is measured orthogonally, extending between interface 106 and surface 122 , in various embodiments. In various embodiments, the thicknesses T B and T C are selectable to fill the volume of a device housing. For example, in one embodiment, the present subject matter creates an index of a plurality of flat capacitors, the index created by measuring the thickness T C of each flat capacitor and storing that thickness in a first index. Additionally, in various embodiments, the present subject matter creates an index of a plurality of flat batteries, the index created by measuring the thickness T B of each flat battery and storing that thickness in a second index. The present subject matter than selects a battery and a capacitor having respective thicknesses T B , T C selected to fill the volume of the targeted device housing.
FIG. 1B illustrates a partial cross section of a device housing 150 , a battery 102 , and a capacitor 104 , according to one embodiment of the present subject matter. In various embodiments, distance D extends between a first interior surface 152 for abutting a battery face 120 , and a second interior surface 154 adapted for abutting surface 122 . In various embodiments, the present subject matter selects a capacitor from a first index, and a battery from a second index, such that the combined thickness of the battery and the capacitor substantially match the thickness D. Additionally, in various embodiments, the selection of battery thickness and capacitor thickness is made in light of the thickness of adhesive layer and/or insulative layers disposed between the battery and the capacitor, and between these respective subcomponents and the device housing. In varying embodiments, the ratio between capacitor thickness and battery thickness is from about 7:1 to about 1.5:1. In additional embodiment, the ratio between the capacitor thickness and the battery thickness is from about 6:1 to about 2:1. Other ratios are possible without departing from the scope of the present subject matter.
In various embodiments, indexing of battery thickness, capacitor thickness, battery perimeter, capacitor perimeter, and other power source parameters is performed using a programmable computer. The present subject matter is not limited to indexes managed by programmable computers, however, as other indexing systems are within the scope of the present subject matter.
FIG. 2 is a perspective view of a capacitor, according to one embodiment of the present subject matter. Substantially flat electrolytic capacitors, in various examples, include a plurality of capacitor layers stacked together. In various embodiments, these stacks of capacitors are assembled into a capacitor case. Various cases are conductive or nonconductive. Some cases include feedthroughs through which conductors pass. The present subject matter includes, but is not limited to, embodiments disclosed on or around pages 12-37, 39, 41-140 of the following related and commonly assigned Provisional U.S. Patent Application “Method and Apparatus for Single High Voltage Aluminum Capacitor Design,” Ser. No. 60/588,905, filed on Jul. 16, 2004, incorporated herein by reference.
In various embodiments, the present subject matter includes a flat electrolytic capacitor 104 with a planar capacitor surface 202 . In various embodiments, the planar capacitor surface includes a capacitor perimeter. In various embodiments, the capacitor stack is adapted to deliver between 7.0 Joules/cubic centimeter and 8.5 Joules/cubic centimeter. Some embodiments are adapted to deliver about 7.7 Joules/cubic centimeter. In some embodiments, the anode has a capacitance of between approximately 0.70 and 0.85 microfarads per square centimeter when charged at approximately 550 volts. In various embodiments, these ranges are available at a voltage of between about 410 volts to about 610 volts.
However, in some embodiments, the stack is disposed in a case, and linked with other components, a state which affects energy density in some embodiments. For example, in one packaged embodiment, including a case and terminals, the energy density available ranges from about 5.3 Joules per cubic centimeter of capacitor stack volume to about 6.3 Joules per cubic centimeter of capacitor stack volume. Some embodiments are adapted to deliver about 5.8 Joules. In various embodiments, these ranges are available at a voltage of between about 410 volts to about 610 volts.
Although these ranges embody one example possible within the scope of the subject matter, the subject matter is not so limited, and other capacitors without departing from the scope of the present subject matter.
FIG. 3 is a perspective view of a battery, according to one embodiment of the present subject matter. In various embodiments, the battery 102 of the present subject matter is substantially flat. Substantially flat batteries, in various examples, include a plurality of battery electrodes stacked together, and further assembled into a battery case. Various battery cases are conductive or nonconductive. Some battery cases include feedthroughs. In various embodiments, the battery cases include a planar battery surface 302 . The present subject matter includes, but is not limited to, embodiments disclosed at paragraphs 0095-0110, 0136-0196, 0206-0258 of the following related and commonly assigned U.S. patent application, “Batteries Including a Flat Plate Design,” U.S. patent application Ser. No. 10/360,551, filed on Feb. 7, 2003, incorporated herein by reference.
FIG. 4 is a perspective view of a battery and a capacitor, according to one embodiment of the present subject matter. In various embodiments, the present subject matter includes a power source 100 which has a battery 102 and a capacitor 104 mated at an interface 106 , at which a planar battery surface and a planar capacitor surface are substantially coextensive. As a result of alignment, various embodiments demonstrate an overall envelope which is substantially continuous. Additionally, in various embodiments, the battery 102 includes a feedthrough ports 108 , 110 . Capacitor 104 includes feedthrough ports 112 , 114 , in various embodiments.
Various capacitor embodiments include a capacitor sidewall 402 , and various battery embodiments include a battery sidewall 404 . Various embodiments additionally include a battery face 120 . A capacitor face is not visible in the illustration due to the orientation of the figure. In various examples, each of these respective case features is planar. When placed adjacent to one another, various embodiments include features which form a substantially planar overall sidewall which is the sum of each of the individual surfaces. In various embodiments, the overall surface is continuous. For example, sidewalls 402 , 404 form a continuous surface. A continuous surface may have a linear shape, or a curvilinear shape. Embodiments having a continuous overall sidewall are within the scope of the present subject matter, however, additional embodiments are possible without departing from the scope of the scope of the present subject matter.
FIG. 5 is a method for constructing a battery and capacitor power source, according to one embodiment of the present subject matter. In one embodiment of the present subject matter, the process includes establishing form factor and power capacity requirements for a power source to be used in an implantable medical device 502 . The embodiment includes constructing a flat battery by stacking flat battery layers into a battery stack and positioning the stack in a battery case with a planar interface and a battery perimeter and battery thickness 504 . The embodiment further includes constructing a flat electrolytic capacitor by stacking flat capacitor layers into a capacitor stack and positioning the stack in a capacitor case with a planar interface and a capacitor perimeter and capacitor thickness 506 . The embodiment additionally includes stacking the flat battery and the flat electrolytic capacitor such that the battery perimeter and the capacitor perimeter are substantially coextensive 510 . This embodiment is illustrative of the present subject matter, but it should be noted that other combinations of steps, and additional steps, also lie within the scope of the present subject matter.
For example, in some embodiments, a battery thickness, battery perimeter, capacitor thickness and capacitor perimeter are selected based on form factor and power capacity requirements for an implantable medical device 508 . Additionally, various method embodiments include measuring a ratio between battery thickness and capacitor thickness, and using this ratio in selecting a battery and capacitor. A ratio is be established by known power requirements, in various embodiments. Another example combines size requirements with power requirements in selecting a ratio. The ratio can be stored and used by a design process or manufacturing process to discern the mechanical and electrical composition of a needed power source, in various embodiments.
In various embodiments, the present subject matter includes delivering from the flat battery and the flat electrolytic capacitor from about 1.25 Joules per Amp hour of battery capacity to about 50 Joules per amp hour of battery capacity. In some of these embodiments, the flat battery has a battery capacity density of from about 0.23 amp hours per cubic centimeter of flat battery to about 0.25 amp hours per cubic centimeter of flat battery. Battery capacity density is measured by dividing the amp-hour rating of the battery by the battery volume, in various embodiments. The present subject matter includes, but is not limited to, embodiments disclosed at paragraphs 0095-0110, 0136-0196, 0206-0258 of the following related and commonly assigned U.S. Patent Publication, “Batteries Including a Flat Plate Design,” U.S. Patent Publication No. 2004/0127952, filed on Feb. 7, 2003, incorporated herein by reference.
In additional embodiments, the flat electrolytic capacitor includes an energy density of from about 4.65 joules per cubic centimeter of flat electrolytic capacitor to 6.5 joules per cubic centimeter of flat electrolytic capacitor. The present subject matter includes, but is not limited to, embodiments disclosed on or around pages 12-37, 39, 41-140 of the following related and commonly assigned Provisional U.S. Patent Application “Method and Apparatus for Single High Voltage Aluminum Capacitor Design,” Ser. No. 60/588,905, filed on Jul. 16, 2004, incorporated herein by reference.
Various methods of the present subject matter benefit from selecting capacitor stack layers and battery stack layers which are substantially parallel to their coextensive case interfaces. By constructing the power source as such, various benefits are possible. For example, in one embodiment, a single two-axis machine can position capacitor layers in a stack, position the capacitor stack in a capacitor case, position battery layers in a stack, and position the battery stack in a battery case. In one embodiment, the single two-axis machine is a pick-and-place machine. This combination is provided for illustration, but other combinations of these steps are possible, and additional steps are also within the scope of the present subject matter.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement which is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover adaptations or variations of the present subject matter. It is to be understood that the above description is intended to be illustrative, and not restrictive. Combinations of the above embodiments, and various embodiments, will be apparent to those of skill in the art upon reviewing the above description. The scope of the present subject matter should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
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The present subject matter includes one embodiment of an apparatus, comprising: a battery including a plurality of flat battery layers disposed in a battery case, the battery case having a planar battery surface which has a battery perimeter; and a capacitor including a plurality of flat capacitor layers disposed in a capacitor case, the capacitor case having a planar capacitor surface which has a capacitor perimeter, the capacitor stacked with the battery such that the planar battery surface and the planar capacitor surface are adjacent, with the capacitor perimeter and the battery perimeter substantially coextensive; a hermetically sealed implantable housing having a first shell and a lid mated to the first shell at a first opening, the first opening sized for passage of the battery, the capacitor, and the programmable electronics, wherein the battery and the capacitor are disposed in the hermetically sealed implantable housing.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of our copending application Ser. No. 126,524, filed Mar. 3, 1980, now abandoned, which is itself a continuation of our application Ser. No. 618,358, filed Oct. 1, 1975, now abandoned. The disclosures of those applications are incorporated herein by reference.
FIELD OF THE INVENTION
This invention relates to heat recoverable products, more especially to heat-shrinkable products, and to such products for use in conjunction with electric circuits carrying high voltage, for example power lines or cables, transformers or switchgear, especially for use as termination systems for high voltage carrying cables.
BACKGROUND OF THE INVENTION
In a continuously shielded or screened high voltage cable, the electric field is uniform along the cable axis, and there is variation in the field only in the radial direction. The spacing of the electric flux lines and the equipotential lines is closer in the region of the conductor than elsewhere, as shown by the following equation: ##EQU1## where E x =electrical stress at point x, in volts/mil
x=distance from centre of cable in mils
V o =applied voltage in volts
R=radius of cable over insulation
r=radius of cable conductor
Thus the stress is a function of the geometry of the cable and in practice the insulation thickness is sufficient to maintain the stresses at acceptable levels for the dielectric concerned. The stress is determined such that the cable will operate continuously at normal working voltages and that the discharge level is acceptably low.
When such a cable is terminated or spliced, the screen or shield is removed for a distance determined by the termination or splicing method. The removal of the screen or shield causes a discontinuity of the electrical field at the screen or shield end, resulting in a high electrical stress. For successful use, the high stress caused here must be reduced to about the maximum level within the cable itself in order not to impair the expected life of the system.
In order to relieve this stress, and prevent failure of the cable and termination or splice in service, a number of methods have been developed to provide adequate stress control. Among these methods may be mentioned the use of stress cones (pre-moulded or fabricated type), resistive coatings and nonlinear tapes.
Stress cones extend the shield or screen of the cable by the use of a conducting material such as wire, metal foil or tapes on part of the surface of an insulating cone. The cone may be made from tapes of plastic or paper, epoxy resins, rubbers etc. Stress cones thus increase the diameter of the cable at the discontinuity and hence reduce the stress. However, their application is labor intensive in that they require considerable skill and time during fabrication on the cable.
Pre-moulded stress cones of the slip-over type may also be used. These require interference fits, which in practice means that both cable and cone have to be made to close tolerance for optimum performance. It has also been proposed to make stress cones by the build up of layers of different lengths of heat shrinkable tubing, but such cones are not very practical as this method is very time consuming and introduces the possibility of interlaminar voids.
Resistive coatings on the surface of the insulation from the conductor to the shield will reduce the stress by conducting sufficient current to establish a substantially linear distribution of voltage. The high resistance necessary to achieve this and to avoid dissipating an excessive amount of power is rather critical and must remain a constant value in service in order to be satisfactory. This is very difficult to achieve in practice and such coatings are not now in general use.
Coverings of preformed sleeves, wrapped tapes such as those based on PVC, or lacquer or varnish coatings, having a non-linear electrical characteristic, have also been proposed to provide stress control. These coverings have the disadvantage that, in general, effective stress control is obtained only by careful and skillful application of the covering and that the materials of the covering deteriorate rapidly at elevated temperatures, by thermal degradation, or by differential thermal expansion between the dielectric and the stress control layer.
It has also been proposed to effect stress control by use of heat shrinkable polymeric articles which have dispersed therein materials giving nonlinear electric impedance characteristics. See, for example, British Pat. Nos. 1,470,501; 1,470,502; 1,470,503 and 1,470,504 and corresponding U.S. application to Penneck and Taylor, Ser. No. 453,165 filed Mar. 20, 1974, abandoned in favor of continuation application Ser. No. 671,343 filed Mar. 29, 1976, abandoned in favor of continuation application Ser. No. 904,736 filed May 11, 1978, the disclosures of which are incorporated by reference. The stress control means may take the form of a heat-shrinkable sleeve which is applied to the portion of the stripped cable which extends from the screen for a pre-determined distance over the cable dielectric. It has further been proposed, for example, in German OLS No. 22 63 909, to apply a layer of a semiconductive paste to the inner surface of a heat-shrinkable sleeve. The sleeve is placed over the stripped cable and heated to force the paste into contact with the cable.
It is advantageous that terminations of high voltage cables for indoor use, and very important that those for outdoor use, are protected against moisture and pollutants, if these are present in the surrounding atmosphere. Such protection may take the form of taping or a sleeve of a material in which, if it is at least partly organic in nature, there may be dispersed an anti-tracking filler, for example hydrated alumina. The anti-tracking filler tends to prevent the formation, on the outer surface of the materials, of carbonaceous, electrically conducting deposits.
It is proposed in British Pat. Nos. 1,337,951, 1,284,082 and 1,303,432 that such protection may be in the form of a heat-shrinkable sleeve of a polymeric material having dispersed therein an anti-tracking filler system.
There are in general use two types of power cable, one comprises oil impregnated papers, wherein paper insulation is applied by helically winding many layers of tape over the conductor, followed by extrusion of a seamless lead or aluminum jacket to provide earth continuity and screening, as well as a moisture barrier and mechanical protection; the assembly is then vacuum dried and impregnated. The second has a polymeric dielectric for example polyvinylchloride, polyethylene which may be cross-linked, or ethylene-propylene rubber. These materials are extruded onto the conductor and where required cross-linked subsequently.
In terminating a high voltage cable by means of heat-shrinkable products, it is necessary in the case of an oil-impregnated paper cable to shrink an insulating heat shrinkable sleeve over the papers. A length of stress grading heat-shrinkable tubing is shrunk in place over the end of the shield to extend for some distance over the dielectric or heat-recovered insulating sleeve, sealant is placed on the uncovered portion of the shield and on the uncovered end of the dielectric or insulating heat-recovered sleeve and a protective heat-shrinkable sleeve of anti-tracking material is recovered over the entire stripped portion of the cable. For outdoor use a number of sheds must be provided on the anti-tracking layer or the anti-tracking heat shrinkable sleeve may be provided with integral sheds as described in British Pat. No. 1,530,994 and U.S. Pat. No. 4,045,604. The disclosures of these are incorporated by reference.
Such terminations have been found to be very satisfactory but although they are considerably time-saving over traditional methods as well as having other advantages, they do involve several separate parts, each of which has to be applied in turn to the cable. This process is time consuming and, if a number of components is used, which is often the case, the process is open to operator error. Clearly, the more operations involved, the more errors are likely to arise. From the foregoing, it can be seen that prior art methods for terminating or splicing high voltage cable are not wholly satisfactory.
SUMMARY OF THE INVENTION
The present invention provides a heat-shrinkable hollow article for use in terminating or splicing a high voltage cable comprising an outer sleeve, the outer surface of which has an initial tracking voltage, as hereinafter defined, of at least 2.5 KV, and a solid layer which has stress grading electrical characteristics on at least a portion of the inner surface, the sleeve being formed of a material to which the property of independent dimensional heat instability, as hereinafter defined, has been imparted, the heat-shrinkability of the article being substantially solely due to said independent dimensional heat instability. The use of a solid layer to provide stress-grading characteristics provides substantial advantages over the use of pastes such as those proposed for use in German OLS NO. 22 63 909, which can readily be wiped off during installation and/or subsequently displaced.
The present invention further provides a method of terminating or splicing a high voltage cable wherein the exposed lengths of the screen, the dielectric and the conductor(s) are protected by shrinking a heat-shrinkable article according to the invention thereover.
The present invention furthermore provides a high voltage cable which has been spliced or terminated by means of a heat-shrinkable, hollow article according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a longitudinal sectional view of a high voltage cable terminated by means of an article according to the present invention.
FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
By the term "heat shrinkable article" there is meant an article which has been expanded under heat and/or pressure from an original configuration to a dimensionally heat-unstable configuration and which has been caused to remain in said heat-unstable configuration, for example by cooling while maintaining the pressure, the article being capable of returning to or towards its original configuration upon the application of heat alone. The temperature or temperature range over which recovery occurs for crystalline polymers will be at or about the crystalline melting point or range for the polymer.
By the term "independent dimensional heat instability" there is meant the property of a homogeneous portion of an article which causes that portion of the article, independently of forces exerted by other portions of the article, on heating, to alter or attempt to alter its dimensions to those which are stable to heat. The term "homogeneous" is used herein to indicate the portion is monolithic and to distinguish the portion referred to from, for example, a laminate, that is, it is used on "macro" rather than on a "micro" scale.
The initial tracking voltage is measured by the inclined plane test of Mathes and McGowan according to the American Society for Testing and Materials (ASTM) D2303. In this test, a sample of the material is mounted at 45° to the horizontal with two electrodes attached to its underside, 50 mm apart. Contaminant in the form of a solution of ammonium chloride, having a volume resistivity of 380 ohm×cm and containing the wetting agent Triton X100, flows at a controlled rate from the upper to the lower electrode. The test is typically commenced at 1.5 KV and the voltage is increased at 0.25 KV per hour until failure occurs.
The outer surface of the heat shrinkable hollow article according to the present invention has an initial tracking voltage (measured in accordance with the ASTM D2303) of at least about 2.5 KV, and preferably 3.5 KV or greater. For the termination of a high voltage power cable, the outer surface of the heat-shrinkable hollow article according to the present invention is preferably non-tracking. By "non-tracking" there is meant that characteristic of a material which results in resistance of a material to the formation of dendritic, carbonaceous, electrically conducting deposits on the material surface under the influence of high electrical voltages.
Materials for use in the article of the present invention having an initial tracking voltage of at least 2.5 KV comprise at least one or more polymeric materials into which an anti-tracking system may be incorporated if necessary. Amongst the suitable polymeric materials there may be mentioned polyolefins and other olefin polymers obtained from two or more monomers, especially terpolymers; polyacrylates; and silicone polymers. Particularly suitable polymers include polyethylene, ethylene/acrylate copolymers, especially ethylene/methyl acrylate copolymers and ethylene/ethyl acrylate copolymers, ethylene/methacrylate copolymers, especially ethylene/methyl methacrylate copolymers and ethylene/ethyl methacrylate copolymers, ethylene/vinyl acetate copolymers, ethylene/propylene copolymers, ethylene/propylene/non-conjugated-diene terpolymers, chlorosulphonated polyethylene, polypropylene, polydimethyl siloxane, dimethyl siloxane/methyl vinyl siloxane copolymers, carborane siloxanes, e.g. "Dexsil" polymers made by Olin Mathieson, the modified elastomer disclosed in British Pat. No. 1,010,064, polybutyl acrylate, butyl-ethyl acrylate copolymers, butyl acrylate/glycidyl methacrylate copolymers, poly-butene, butyl rubbers, ionomeric polymers, e.g. "Surlyn" materials made by Du Pont, substantially mono alkyl silicones especially those having a carbon/silicon ratio of 1.5:1 to 1:1, especially substantially monomethyl silicones, substantially mono alkyl-silicones in dimethyl silicones or mixtures of any two or more of the above. The method in which such polymers are rendered heat recoverable is now well known in the art and the details of this method will not be repeated here. Reference can be made to the prior art, for example, Cook U.S. Pat. No. 3,086,242, which is incorporated herein by reference, for a suitable procedure.
For the anti-tracking system there may be mentioned hydrated alumina, especially those systems disclosed in British Pat. No. 1,041,503, especially alumina trihydrate, one or more of the alkaline earth sulphates according to British Pat. No. 1,240,403 and the anti-tracking materials of British Pat. No. 1,337,951 and corresponding U.S. application of Penneck, Ser. No. 81,558 filed Oct. 16, 1970, abandoned in favor or continuation application Ser. No. 434,126 filed Jan. 17, 1974, abandoned in favor of continuation application Ser. No. 109,249 filed Jan. 3, 1980, now abandoned, each of which may be incorporated into the polymeric material either alone or in a blend with one or more other anti-tracking systems. The disclosures of these are incorporated by reference. For especially suitable materials having tracking characteristics according to the present invention there may be mentioned the composition disclosed in British Pat. No. 1,337,951 and the corresponding U.S. application referred to above but any material having the required anti-tracking characteristics may be understood to be suitable for an article according to the present invention. This particularly preferred composition comprises a mixture of a hydrate of alumina having a specific surface area of at least 2 m 2 /g, measured by the BET method, and a compound from the group consisting of oxides, mixed oxides and mixtures of oxides wherein said compound contains at least one element from the transition elements, the lanthanide series or the non-transuranic actinide series.
By a "transition element" there is herein meant the elements of sub-groups IVa, Va, VIa, VIIa, and Group VIII of the Mendeleef periodic table which are not also in the nontransuranic actinide series, e.g., titanium, zirconium, and hafnium; vanadium, niobium, and tantalum; chromium, molybdenum and tungsten; manganese, technetium, and rhenium; and iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum.
By "lanthanide series" there is herein meant the elements cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.
By "nontransuranic actinide series" there is herein meant the elements thorium, protactinium, and uranium.
Among oxides, mixed oxides and mixtures suitable there may be mentioned, for example,
(i) Transition metal oxides, for example, TiO 2 , V 2 O 5 , Cr 2 O 3 , NiO 2 , Ni 3 O 4 , Co 2 O 3 , Co 3 O 4 , MoO 3 , WO 3 , Nb 2 O 5 , and mixtures thereof.
(ii) Lanthanide series oxides, for example, Pr 6 O 11 , Yb 2 O 3 , Ce 2 O 3 , holmium oxide, erbium oxide, and mixtures thereof.
(iii) Nontransuranic actinide series oxides, for example, UO 3 , ThO 2 and mixtures thereof.
(iv) Mixed oxides containing one or more transition metals, for example, nickel titanate, nickel molybdate and cobalt silicate.
(v) Any of the above oxides, mixed oxides or mixtures carried on an ahydrous alumina support, e.g., nickel cobalt molybdate on alumina and cobalt oxide on alumina CoO. Al 2 O 3 (blue cobalt aluminate).
(vi) Any of the above systems doped with small quantities of alkali metal or alkaline earth metal oxides, especially Li 2 O and K 2 O.
It is understood that the above listing is illustrative only, and is not intended to be a complete list of all the oxides which are operable in the invention.
The oxide component, which is believed to react synergistically with the alumina hydrate in reducing tracking, may in some cases be used in quantities down to or below 0.5% by weight based on the total weight of the insulation material, but in general is preferably present in an amount in the range of from 2 to 10%, especially from 3 to 5%. Although amounts higher than 10% may be employed, little additional benefit to the tracking and erosion properties is gained thereby with most oxides. However, with some oxides of the invention e.g., ThO 2 , the oxide is preferably present in quantities of about 15% or more by weight.
The layer on the inner surface of the heat shrinkable hollow article has stress grading electrical impedance characteristics, which may be linear or, preferably, nonlinear in nature. These may be resistive, capacitive, or a combination thereof and the resistive component may be linear or nonlinear. By the term "linear electrically resistive material" there is meant a material which upon the application of a voltage obeys Ohm's Law. By the term "non-linear electrically resistive material" there is meant a material, the electrical resistance of which varies with the voltage applied, that is, the current I flowing through the material when a voltage V is applied across the material substantially obeys the relationship: I=KV.sup.γ wherein K is a constant, and γ is a constant, greater or less than 1. Preferably, γ is at least 1.5 at some direct current stress between 0.01 KV/mm and 10 KV/mm, advantageously at least 1.5 at a stress below 5 KV/mm.
The heat-shrinkable hollow article comprises a polymeric heat-shrinkable outer sleeve of one of the aforementioned polymer systems having an initial tracking voltage of at least 2.5 KV, preferably being non-tracking, and a layer, which is solid at room temperature, on at least a portion of the inner surface of said outer sleeve, at least the inner surface of said layer having stress grading, preferably non-linear, electrical impedance characteristics.
Layers having stress grading electrical characteristics may comprise a base of, for example, a polymeric material, mastic, paint or varnish, admixed with a compound having stress grading electrical properties provided that the layer does not interfere in any substantial way with recovery of the outer sleeve from its heat-unstable to its heat-stable configuration.
The layer may be applied to the inner surface of the outer sleeve by any known method, for example, moulding, extrusion, painting or spreading. The layer may be applied in the form of a solution, the layer adhering to the inner surface of the outer sleeve upon evaporation of the solvent. Where the layer is, for example, a polymeric material, it may be extruded as a tube and placed inside and advantageously adhered to the outer sleeve such that on heat-shrinking of the article, the layer will be forced into intimate contact with the directly overlying portion of the inner surface of the outer sleeve. The tube may be adhered to the portion of the outer sleeve to form the article of the invention and the article may be subsequently rendered heat-shrinkable.
The material forming the base of the layer in which a compound giving stress grading electrical characteristics can be incorporated is advantageously polymeric and may be selected from a large range of polymers, of any molecular weight. Blends of two or more polymers, into which there may be incorporated conventional additives, may be desired and the materials forming the base will be selected depending to a certain extent on the form of the coating. Examples of polymers suitable either alone or in blends are as follows: Polyolefins, including copolymers of ethylene with propylene, butene, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinyl acetate, vinyl chloride, vinyl propionate, carbon monoxide, maleate, fumarate and itaconic esters, terpolymers of ethylene, vinyl acetate and olefinically unsaturated monocarboxylic acids, for example acrylic or methacrylic acids; the partially neutralized varieties of polymers comprising acid groups, for example ionomeric resins, which generally are the ammonium or alkali or alkaline earth metal derivatives; polyvinyl chloride, vinyl chloride copolymers containing as comonomer vinyl acetate, vinylidene fluoride, dialkyl maleate, or fumarate; fluoro carbon plastics or rubbers including polyvinylidene fluoride, copolymers of vinylidene fluoride and hexafluoropropylene, terpolymers of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene, copolymers of vinylidene fluoride and 1-hydropentafluoro propene or a terpolymer containing these monomers plus tetrafluoroethylene; nitrile rubbers, acrylate rubbers, and polysulphide rubbers; natural rubbers, synthetic rubbers such as butyl, neoprene, ethylene propylene rubber and the ethylene propylene non conjugated diene terpolymers, silicone rubbers, including those derived from dimethyl siloxane, methylphenyl siloxane, or methyl phenyl vinyl siloxane; these rubbers preferably being "gum form"; also "gum" polyesters, "gum" polyamides and other polymers or copolymers in "gum" form.
For compounds having stress grading electrical characteristics which may be incorporated in the base comprising, for example, a blend of two or more of the above-mentioned materials together with any number of conventional fillers, for example, processing aids, plasticizers, stabilizers, antioxidants, coupling agents, further modified or unmodified fillers and/or cure systems, there may be mentioned, for example, carbon black or silicon carbide particles, flakey metals, for example those described in U.S. Pat. No. 3,349,164, and the materials of British Pat. Nos. 1,470,501; 1,470,502; 1,470,503 and 1,470,504 and corresponding United States application Ser. No. 453,165 filed Mar. 20, 1974, abandoned in favor of continuation application Ser. No. 671,343, filed Mar. 29, 1976, abandoned in favor of continuation application Ser. No. 904,736, filed May 11, 1978, the disclosures of which are incorporated by reference. One or more of these compounds having stress grading electrical characteristics may be blended into the base material of the layer.
Among useful stress grading compositions may be mentioned particulate compounds selected from the group consisting of:
(i) Compounds having a perovskite type crystal structure.
(ii) Compounds having a spinel crystal structure other than γ-Fe 2 O 3 and spinel itself.
(iii) Compounds having an inverse spinel crystal structure.
(iv) Compounds having a mixed spinel crystal structure.
(v) Dichalcogenides of transition metals.
(vi) Ferro-electrical materials such as AgI, Prussian Blue, Rochelle salt and related tartrates, compounds of the formula XH 2 YO 4 wherein X is K, Rb or Cs and Y is P or As, for example potassium dihydrogen phosphate, (NH 4 ) 2 SO 4 , ammonium fluoroberyllate, thiourea and triglycene sulphate.
(vii) Si 3 N 4 .
The said particulate compound can be present in an amount of at least 10% by weight based on the polymer, and in an amount such that the value of γ at some stress between 0.01 KV/mm and 10 KV/mm is at least 1.5. Preferably the value of γ is at least 1.5 at a stress below 5 KV/mm.
In addition to the materials listed in (i) to (vii) above, the material may comprise one or more particulate electrically conductive fillers.
As compounds of the type (i) above, there may be mentioned, for example, compounds having the general formulae:
(a) ABO 3 wherein A represents Ca, Sr, Ba, Pb, Mg, Zn, Ni or Cd and B represents Ti, Zr, Hf, Sn, Ce or Tc or A represents a rare earth metal and B represents Al, Se, V, Cr, Mn, Fe, Co or Ga,
(b) KBF 3 wherein B represents Mg, Cr, Mn, Fe, Co, Ni, Cu or Zn, or
(c) ATiS 3 wherein A represents Sr or Ba, and AZrS 3 wherein A represents Ca, Sr, Ba.
There may be especially mentioned BaTiO 3 , BaSrO 3 and TnTiO 3 and the following, which are preferably used in admixture with a particulate conductive filler: BaZrO 3 , CaTiO 3 , CaSnO 3 , CaZrO 3 , PbSnO 3 , MgZrO 3 , NiTiO 3 and mixed zinc titanate.
As compounds of the type (ii) there may be mentioned, for example, compounds having the general formula:
(d) A"B 2 "'O 4 wherein A represents Hg, Mn, Fe, Co, Ni, Cu, Zn or Cd etc. and B represents Al, Cr, Fe, Mn, Co or V, provided that when A represents Hg, B cannot represent Al, or
(e) A"B" 2 O 4 wherein A represents Ti or Sn and B represents Zn or Co, Ni, Mn, Cr, Cd.
There may be especially mentioned CoAl 2 O 4 , CuCr 2 O 4 , CuMnO 4 , CuFe 2 O 4 , ZnFe 2 O 4 . Barium and strontium ferrites (e.g. BaFe 12 O 19 ) which are of the magneto-plumbite structure (a type of depleted spinel) are also suitable.
As compounds of the type (iii) there may be mentioned, for example,
(f) Fe"'(Mg"Fe"')O 4 , Fe"' (Ni"Fe"')O 4 , Fe"' (Cr"Fe")O 4 , Co"(Co"Sn)O 4 , Zn"(Zn"Ti)O 4 , Zn"(Zn"Sn)O 4 , Li 2 V 2 O 4 , Fe 2 .5 Li 0 .5 O and, especially, Mn 3 O 4 , Co 3 O 4 , Fe 3 O 4 and slightly non-stoichiometric variants thereof, for example Fe 2 O 3 .0.8FeO.
As compounds of the type (iv) there may be mentioned, for example, Bayer Fast Black 100 (which results from sintering 50% by weight Co 2 O 3 , 40% by weight Fe 2 O 3 and 10% by weight CuO), Bayer 303T (a mixed phase pigment of about 2/3 Fe 2 O 3 and 1/3 MnO), Harrison Meyer Black (an Fe-Co-Ni mixed oxide) and Columbian Mapico Black (a synthetic magnetite of about 22% FeO and 77% Fe 2 O 3 ).
As compounds of the type (v) there may be especially mentioned, for example, MoS 2 , MoSe 2 , MoTe 2 , WS 2 , MnO 2 , FeS 2 , SnO 2 , and CrO 2 .
Si 3 N 4 and CoAl 2 O 4 mentioned above are preferably used in admixture with a particulate, conductive filler.
As conductive particulate fillers there may be mentioned, for example, carbon blacks, metallic powders, for example aluminum, chromium, copper, bronze, brass, iron, stainless steel, lead, silver, manganese, zinc, Ni/Al and nickel powders, and particulate platinized- or palladized-asbestos, -silica, -alumina, and -charcoal.
The compounds may also be used in admixture with silicon carbide particles.
The proportion of particulate compounds and fillers may be widely varied, depending on (a) the electrical properties required of the material, (b) the chemical nature of the polymer. The desired proportion may be determined relatively simply by experimentation. In general, the particulate compounds will be present to at least 10% by weight of the polymer and more particularly the weight ratio of particulate compound to polymer will be within the range of from 10 to 500:100. The conductive particulate filler will generally be used in a concentration up to a maximum of 40 parts in the case of carbon black and of 100 parts in the case of metal powders relative to 100 parts by weight of polymer particularly when gamma is greater than one. Typical values for the conductive particulate filler are in the region 10-25 parts (carbon black) and 50 to 100 (metal powder) per 100 parts of polymer.
The particle sizes of the particulate compounds are preferably below about 20μ, more preferably below about 5μ. Generally the smaller the particle size the better are the physical properties of the article.
Preferably a sealant is placed on at least a portion of the inner surface of the outer heat-shrinkable sleeve on an area where there is no inner stress grading layer.
Of suitable sealants there may be mentioned hot melt adhesives, mastics and thremosetting adhesives. The composition of the sealant may depend on the nature of the substrates between which sealing against, for example, moisture ingress is desired. Of suitable sealants for, for example, bonding the heat-shrinkable outer sleeve to the exposed cable jacket and/or to the metal lug attached to the center conductor(s) there may be mentioned, for example, the adhesives of British Pat. No. 1,425,575 and corresponding U.S. Pat. No. 3,983,070 or those of British Pat. No. 1,411,943 and corresponding U.S. Pat. No. 4,001,065. The disclosures of these are incorporated by reference.
EXAMPLE 1
A 20 KV cable having a cross-linked polyethylene insulation was stripped to expose 7.5 cm of the conductors, 43 cm of the dielectric, 1 cm of the graphite layer, 1 cm of the paper layer and 2 cm of the copper screen. A lug was crimped onto the conductors.
A stress grading mastic containing 150 g of iron oxide, Fe 3 O 4 (BX 5099 made by Pfizer Ltd), 50 g butyl rubber (Butyl 065, made by Esso Petroleum Ltd.) and 50 g of polyisobutylene (Vistanex OMMS, made by Esso Petroleum Ltd.) was mixed and coated onto a 25 cm portion 6 cm from the end of a 56 cm length of a heat-shrinkable, non-tracking sleeve by means of a ram extruder having a mushroom-shaped die-head. A mastic containing butyl rubber, as above, and polyisobutylene, as above, was mixed and internally coated onto a 4 cm portion of each end of the heat-shrinkable, non-tracking sleeve. The heat-shrinkable non-tracking sleeve manufactured according to Example 1 of British Pat. No. 1,337,951 was heat-recovered to cover 2 cm of the cable jacket and the stripped portion of the cable.
The cable was tested to give the discharging inception voltage of 5 pc at 50 KV on an ERA Mark III Discharge Detector. According to British Standards BS 923 (1972) the impulse withstand voltage was measured with positive and negative polarity giving 115 KV and the impulse flashover voltage was measured with positive polarity to give 120 to 125 KV.
EXAMPLE 2
A second cable was terminated using the same procedure except that the stress grading mastic comprised low density ethylene propylene rubber and silicon carbide particles. Similar electrical results were obtained.
The present invention also provides an article in which the independent dimensionally heat unstable portion of the article is replaced by a dimensionally unstable portion that is restrained by a further portion which is removable, the removal allowing the dimensionally unstable portion to return to a dimensionally stable state. The further portion may be for example a spirally wound plastic or metal spring or tape, which may be inside or outside the article.
Referring now the drawings, FIG. 1 illustrates a stripped high voltage cable denoted generally by 1. The cable is stripped to show its components which comprise a jacket 2, a copper screen 3, a paper layer 4, a graphite layer 5, a plastic dielectric 6, and conductors 7. A lug 12 has been crimped onto the conductors 7. An article denoted generally by the numeral 8, according to the invention, has been heat-recovered onto the stripped portion of the cable from the jacket 2 to the cable lug 12. The article 8 comprises an outer sleeve 9, having an initial tracking voltage as hereinbefore defined of at least 2.5 KV, an inner coating 10 of a material having nonlinear electrical resistance properties, and sealing means 11 and 11A.
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Terminations and splices in high voltage electrical cable can be shielded by shrinking over the termination or splice a heat recoverable hollow article which comprises a heat-shrinkable outer sleeve whose outer surface is anti-tracking at voltages of 2.5 KV and at least part of whose inner surface has a layer thereon which is solid at room temperature and which has electrical stress-grading character.
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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
This invention was made with Government support under Contract DEAC04-94AL85000 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.
CROSS-REFERENCE TO RELATED APPLICATIONS
None.
BACKGROUND OF THE INVENTION
This invention relates to the measurement of structures down to and below about 100 nanometers in size by indirect optical methods. More particularly, this invention exploits the interaction of an evanescent electrical field arising from an optical resonator structure with the structure of the measured object. This invention will find immediate application to wafer Critical Dimension metrology in the microelectronics art.
For routine critical dimension (CD) metrology on process wafers, there are at least four possible approaches: (1) far-field optics, (2) scanning electron microscopy (SEM), (3) scanning probe microscopies (SPM) such as near-field scanning optical microscopy (NSOM), and (4) scatterometry.
Each of these techniques have their advantages, as well as their limitations. Optical microscopy is non-invasive, robust, and inexpensive. However, the resolution of a far field optical instrument is Rayleigh limited. At optical wavelengths, sub-micrometer measurements are difficult due to the present computational intractability of the inverse problem. After a slow start in the early 1980's the SEM is now the workhorse of the semiconductor industry for wafer CD metrology. It promises to provide reliable linewidth measurements down to about 250 nm. However, the SEM is an invasive method and requires the inconvenient step of taking the wafer to high vacuum. SPM techniques are conceptually simple and essentially non-invasive. However, the tip convolution problem may prove impossible to overcome. For example, the NSOM tip is typically 250 nm wide (including the aluminum cladding) and must be brought to within about 10 nm of the sample. Therefore, NSOM cannot readily determine linewidths of high aspect ratio structures. Scatterometry appears to have considerable promise at the 250 nm feature size. However, it requires a rather large grating test structure in the scribe-grid and cannot be applied to isolated features.
Simply put, there is an unmet need in the semiconductor wafer processing art to be able to determine the topography of critical dimension structures on the wafer for dimensions at or below 100 nm feature size in a rapid and convenient manner.
BRIEF SUMMARY OF THE INVENTION
The various shortcomings and drawbacks of the prior art are overcome by the novel near-field optical probe of this invention. The basic concept is to observe resonance shifts in a waveguide cavity that arise from the coupling of the evanescent field of the waveguide to perturbations beneath the waveguide plane. The change in resonance frequency is detected as a change in the transmission of a monochromatic probe beam through the waveguide. The transmitted intensity, together with the appropriate signal processing, gives the topography of the perturbation. Simulations indicate that this probe is capable of determining the width of photoresist lines smaller than 100 nm. The preferred working distance of 100 to 250 nm is much more practical than the other probe technique discussed above.
This basic structure of the optical waveguide can take a number of different forms so long as it can successfully couple the evanescent field arising from light resonating in a cavity to a perturbing structure that is moved past the cavity and then measure the variations in the intensity of the light transmitted by the cavity resulting from the perturbations. Planar and rib waveguides and specially treated single mode optical fibers may be employed. These waveguides may be linear or two-dimensional. A complete two-dimensional image of an object requires a two-dimensional resonator and/or a two-dimensional scan. The two-dimensional probe may be based on a circular planar resonator structure. Alternatively, a two-dimensional image may be acquired using a one-dimensional probe (i.e. a rib waveguide optical resonator structure) by taking two sets of scans, rotated by 90 degrees.
In one preferred rib waveguide embodiment, the optical waveguide resonator has its resonator in a central region of the device with a cavity length of an integral multiple of one half the wavelength of the light used in the device. The waveguide is a rib waveguide with the light being guided by the rib. The resonator cavity forms part of the rib. On either side of the resonator and also part of the rib are Bragg reflector layers that are oriented vertically and perpendicular to the axis of the rib. At the ends of the rib are input and output gratings to couple light into and out of the waveguide. Facing the rib and the central region resonator is the object to be measured. Typically the optical waveguide is stationary, and the object is moved past it at a separation distance of from about 50 to about 300 nanometers, or, more preferably, about 100 to about 250 nanometers. As light passes through the waveguide, an evanescent electrical field is created about the resonator. When a refractive discontinuity created by a structure on the object gets sufficiently close to this evanescent field, it perturbs this field, and the resonance and the signal strength of the light passing through the resonator will change. The change in the intensity of the light that passes out of the waveguide is then measured, and the topography of the structures on the object can be determined.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1 is a schematic diagram of a portion of the optical waveguide showing the structure of the resonant cavity and the Bragg reflector layers.
FIG. 2A, 2B and 2C show the relative movement of the optical waveguide past the object with the perturbing structures, the electric field in the direction normal to the plane of the waveguide, and the electric field parallel to the plane of the waveguide.
FIG. 3 is a cross sectional diagram of the operational mode of one embodiment of the invention.
FIG. 4 is a diagram of the computed topographic profile of a series of photo-resist lines on poly-Si.
FIG. 5 is a curve representing simulated signals before deconvolution from the light intensity variations induced by the structures shown.
FIG. 6 is a diagram of a metrology system incorporating the invention.
DETAILED DESCRIPTION OF THE INVENTION
The invention employs a novel use for an optical waveguide resonator structure. The resonator is formed by two Bragg reflectors that are shifted by a quarter-wave to form a half-wave cavity. Related structures are discussed in two papers by H. Haus and Y. Lai, "Narrow-Band Distributed Feedback Reflector Design," Jour. of Lightwave Tech., 9, pp. 754-760 (1991) and "Narrow-Band Optical Channel-Dropping Filter," Jour. of Lightwave Tech., 10, pp. 57-62, (1992). There are a number of possible embodiments for the optical waveguide structure. The preferred embodiment discussed in detail below is for a rib waveguide structure. However, those skilled in the art will understand that the basic structure only requires an optical waveguide tuned to a certain wavelength of light that includes a central resonant cavity flanked by Bragg reflector layers with associated means to get the light into and out of the waveguide. It is possible to construct such a waveguide as a planar waveguide structure by carefully implanting ions into certain areas to form the basic waveguiding means to confine at least one mode of the light and to form the resonant cavity and the alternating low and high refractive index layers of the Bragg reflectors. It is also possible to form the optical waveguide from a suitably treated single mode optical fiber which is modified to create the necessary zones of differing refractive index necessary to form the resonant cavity and the Bragg reflector layers. This optical fiber embodiment would not be as efficient in its ability to couple the created evanescent electrical field since the field would radiate in all directions about the axis of the fiber instead of only outward in one direction from the resonant cavity in a planar or rib waveguide.
A representation of the preferred embodiment of the optical waveguide resonator useful in this invention is shown in FIG. 1. The basic structure of the waveguide 10 is that of a silicon dioxide substrate 11 capped with a silicon nitride layer 12 with most of the upper region of the nitride layer 12 etched away to form the rib 14, the complete ensemble thus forming the waveguide. Only a portion of the complete waveguide structure is shown in this view. The substrate and rib regions 18, 19 extend out to the left and right to a total length on the order of magnitude of about 5 mm.
The light is bound to the rib 14, being either within the rib or just below it. The resonant cavity 15 is formed in the central region of the rib as shown. The Bragg reflector layers 16, 17 are formed adjacent to the resonant cavity. The resonant cavity has an optical length that is an integral multiple of the one half the wavelength of the monochromatic light used in the waveguide 10. Each individual Bragg reflector layer has an optical length that is one quarter of the wavelength of the monochromatic light, although such length could also be an odd integer multiple of the preferred one quarter wavelength distance. As is well known in the art, the Bragg reflectors form mirrors at the selected light wavelength, due in part to the refractive index contrast between the individual layers in the mirror structures 16, 17. The simplest embodiment is to etch away the silicon nitride of the rib in 1/4 wavelength slices as shown in FIG. 1. The resonator cavity 15 is formed in the same way. The refractive index of these etched away regions is then that of air. The remaining silicon nitride Bragg layers have the refractive index of silicon nitride, providing a favorably large difference in the refractive indices of the Bragg layers. It would also be possible to redeposit another material in these etched away areas if it were necessary to tailor the refractive indices further. Although this view shows the etched away regions that form 1/2 of the Bragg layers and the resonator cavity extending down to the bottom of the rib, this depth could be reduced somewhat and still retain the functionality of the waveguide structure 10.
The unperturbed waveguide 10 functions in the following manner. Light entering from the left end 19 of the waveguide encounters the first mirror structure 16, and most of it is reflected back. A portion of the light passes into the resonant cavity 15 and encounters the other mirror structure 17 where, again, most of the light is reflected back into the cavity. Since the cavity 15 is of a length that supports a resonance condition, the light will tend to bounce back and forth within the cavity 15 with only a small portion passing out the other end 18. This small portion is then collected and measured.
The first step in fabricating the resonator is to grow a thin-film waveguide. The SiO 2 system is preferred since it is transmissive at 1550 nm and can be readily fabricated. Next, patterning and etching are used to form the rib waveguide and finally the Bragg grating structure. The specific process steps involved in such fabrication are within the ordinary skill in the art. Although somewhat counterintuitive, the longer 1550 nm wavelength actually works better than shorter wavelengths in this material system. The lengths of the various Bragg reflector layers and the resonant cavity are a function of the longer wavelength, and, being larger, are easier to fabricate than the shorter structures that would be dictated by the use of a shorter wavelength. One should remember that the resolution of this invention depends on the strength of the coupling between the evanescent field and the structures on the object to be measured. The resolution will typically not be improved by moving to shorter wavelengths.
FIGS. 2A, 2B, and 2C show the electric field distributions, in the z and x directions, of the lowest resonant mode of the resonator. In the x direction only the exponential envelop is shown in FIG. 2C while the high frequency structure related to the Bragg gratings is omitted. The FWHM of this exponentially decaying field is about 10 μm for a pair of Bragg structures that extend about 70 μm. The evanescent tail, in the z direction, probes the region immediately beneath of the cavity as seen in FIG. 2B. The separation of probe 10 and sample 24, h, is about 100 to 250 nm as seen in FIG. 2A. The resonant frequency of the cavity 15 changes as the dielectric perturbation 25 is translated along the ξ direction. This change in the resonant frequency results in a corresponding change in the transmission of monochromatic light through the waveguide resonator.
FIG. 3 is a schematic drawing indicating one embodiment of mode of operation of the probe 10. Shown in the figure is a scheme using second-order grating couplers 30, 31 (couplers with 30-40% coupling efficiencies are relatively easy to fabricate); however, other methods such as prism coupling can also be used. The structures 32 on the wafer 33 to be interrogated are placed beneath the resonator 15 at a distance of about 100 to 250 nm and translated by use of scanning stages 34 along a portion (perhaps 20 μm) of the length of the Bragg structure 16 and 17. The intensity of the light transmitted through the waveguide resonator is the signal from which the topography of the structure is ascertained. The laser light source, not shown, can be tuned so that maximal transmission occurs when the perturbing structure is more or less centered beneath the cavity. This tuning technique produces the data presented herein. Alternatively, the laser can be tuned for maximal transmission without the presence of the perturbing structures. This practice may be preferable, but will result in the collected data being `upside down` when compared to the data presented in the Figures herein.
It is important that the separation distance between the probe and the object be kept relatively constant as they translate pass each other. In CD measurements on wafers this can be done by known interferometric techniques measuring the distance between a mirror located on the measurement tool and the surface of the wafer. Since the CD structures are located on the scribe grids between the die on the wafer, it is not likely that there would be any abrupt changes in topography on the wafer other than the CD structures themselves, and the problem is not likely to be severe. The deconvolution calculations are relatively insensitive the separation distance itself.
The principal reason why this technique can provide high resolution is that the deconvolution or inverse problem has a straightforward solution, whereas in other measurement techniques, the deconvolution is difficult, if not impossible, to perform. Any measurement process (be it optical, SPM, SEM etc.) can be summarized as
S(ξ)=H(ξ)t(ξ)
where the measured signal S(x) is a convolution of the actual topography t(x) with the instrument response, H(x). If H(x) were known, then t(x) could be readily ascertained. For example, the National Institute of Standards and Technology's (NIST) photomask standard (SRM 473) is established by calculating H(x) theoretically by a numerical solution of the vector diffraction problem (i.e. solving Maxwell's equation). Unfortunately, the approach undertaken by NIST to establish a photomask standard is not so reliable when applied to wafer metrology. The influence of poorly defined underlying layers breaks the connection between the theoretical results and their practical application. Variations in film thicknesses that are perfectly acceptable from the standpoint of electrical device function may seriously interfere with the precision and accuracy of CD measurements. Also, for microscopies relying on scanning mechanical tips the inverse problem is virtually intractable owing to a lack of precise information on the shape of tip and the microscopic interactions between the tip and sample.
However, with the resonator probe described here, this deconvolution is quite straightforward because the guided modes in waveguides are relatively easy to describe theoretically. In fact, simple analytical models can describe accurately (within a few percent) the changes in the resonance frequency. For example, the transmission near the resonance frequency, w 0 , for a high-Q resonator is well described by a Lorentzian: ##EQU1## where β(ξ) is the shift in resonance frequency and Γ(=1/2 Q) is the linewidth. Therefore, from a measurement of transmission (which is merely proportional to the detected power), one obtains the resonance shift. For modeling and design the Lorentzian approximation is acceptable. In actual practice, one could readily determine the lineshape function empirically and use this empirical function independent of the application. Reference is made to the papers by Haus and Lai mentioned above.
The shift in resonance frequency, β(ξ), can in turn be related to the topography. This is most easily understood from cavity perturbation theory where ##EQU2## and ΔE stored (ξ)/E stored is the fraction change in the stored energy in the resonator due to the perturbation.
The stored energy change can be shown to be expressible in the form shown:
ΔE.sub.stored (ξ)=H.sub.probe (ξ)t(ξ)
where H(ξ) is now the transfer function of the probe. A reasonably accurate transfer function can be obtained by perturbation theory; however, a more exact and rigorous function can be obtained by numerical (such as the beam propagation computer codes developed at Sandia) and empirical methods. It should be noted that the perturbation model is routinely used in the literature pertinent to microwave cavities and circuits and provides estimates that are accurate to within a few percent.
To summarize the steps in the modeling exercise, the resonant cavity probe is moved across a surface with the feature of interest. The simulated transmitted signal is calculated at equispaced positions relative to the center of the cavity. This gives a signal reminiscent of the function for |E(ξ)| 2 in FIG. 2 with the high frequency portion of the electric field convoluted with the topography of the sample. Laser and detector noise contributions to the signal are included in the simulation, and ultimately limit the resolution. Using the Lorentzian model, the frequency shift is calculated and, from its Fourier transform, the response of the resonator is deconvolved. In order to suppress aliasing and other related effects, the signal is filtered using well known techniques in signal processing (e.g. Hanning filter). Finally, the inverse Fourier transform, to complete the deconvolution, yields the topography.
With the model briefly described above the performance of the waveguide resonator probe was simulated. FIG. 4 presents representative results from these simulations. The calculations were based on a 1 mW 1550 nm diode laser coupled to a 70 μm long Bragg resonator with 10% coupling efficiency. Room-temperature operation (e.g. InGaAs detectors) is assumed, and the effects of laser and detector noise have been included. A simple deconvolution and filtering method was used in order to get rough performance estimates. Simulations that include more sophisticated data processing may predict even higher effective resolution.
In FIG. 4, the reconstructed topography is plotted for four photoresist lines on poly-Si, with spaces of varying widths. In the simulation, the sample was translated in 20 nm increments for a total of 2000 calculations of transmitted intensity. After the appropriate data processing the resulting trace faithfully reproduces the topography. This modeling result indicates that the new method can effectively measure CDs at least as small as 100 nm. The noise in the trace is a result of the inclusion of both laser and detector noise in the model. The simulation was conservative in this regard. State-of-the-art detection methods (e.g. homodyne), may produce lower noise than modeled in FIG. 4 and hence a higher effective resolution. FIG. 4 is a end-product of simulated data before reconstruction found in FIG. 5. Shown in FIG. 5 are the measured structures 70 and the simulated data displayed as the curve 72. By inspection of the curve 72, one may ascertain the three (other than noise) contributing components. The low frequency exponential slopes are comparable to FIG. 2C and represent the translation of the object past the resonant cavity. Superimposed on the low frequency exponential slopes is a fairly constant higher frequency sine wave which represents the periodicity of the Bragg reflector layers in the probe. Superimposed on the higher frequency sine wave is even higher frequency information which represents the desired topography of the structures 70 being measured. Hence, if the first two components are deconvolved from the light intensity data 72, only the topography (and noise) information remain.
FIG. 6 shows the concept for a proposed instrument. A conventional microscope 60 is used to locate the line to be measured on the wafer 33. The probe 10, which is at a known offset from the microscope's cross-hairs, is automatically brought over the line to be measured by movement of the fine and coarse stages 62, 64. The scan in a single direction is repeated the desired number of times to improve signal to noise. The deconvolution is performed and the linescan (as in FIG. 4) is displayed along with the linewidth measurement result.
Another interesting variant for utilizing the proposed instrument is to perform scans at several heights above the wafer. Preliminary studies show that it may be possible to reconstruct from these top-down measurements the physical sidewall profile of a line or space in photoresist. While other methods can also do this in principle, they have failed in practice. The simplicity of the inverse problem for this new type of probe may now make such determinations possible.
The leading edge products in the semiconductor industry will switch to a 0.25 μm process in 1998 and to a 0.18 μm process in 2001. The need for robust metrology tools with sufficient precision as well as accuracy at these dimensions is therefore clear. Among the principal features of the concept described here are: (1) it is a high resolution technique, (2) it is non-invasive, and (3) it operates under ambient conditions. These features give it the potential for displacing the SEM for routine CD measurements on wafers. Unlike NSOM, which also is a high resolution technique, the working distance of the new probe is convenient at about 100 to 250 nm. Furthermore, the evanescent field does not probe too deeply into the wafer surface. Unlike conventional optics (and presumably NSOM) the proposed instrument is essentially immune to poor CD precision caused by variations in underlying layers. Another unique feature of this probe, relative to conventional optics, is that there is no hard theoretical limit for the resolution. Ultimately, the signal-to-noise-ratio limits the resolution.
Finally, this probe has potential application to optical data storage. The best commercial technology operates at a density of about 1 Gbits/inch 2 . Even with advances in shorter wavelength blue-green semiconductor diode lasers, raw storage densities beyond 3-5 Gbits/inch 2 do not appear feasible. This new probe could potentially increase this density 5-10 fold. In this sense, the measurement of structures as claimed herein after is intended to cover the detection of the presence of the pits in the optical storage media that represent the data contained therein.
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A resonant planar optical waveguide probe for measuring critical dimensions on an object in the range of 100 nm and below. The optical waveguide includes a central resonant cavity flanked by Bragg reflector layers with input and output means at either end. Light is supplied by a narrow bandwidth laser source. Light resonating in the cavity creates an evanescent electrical field. The object with the structures to be measured is translated past the resonant cavity. The refractive index contrasts presented by the structures perturb the field and cause variations in the intensity of the light in the cavity. The topography of the structures is determined from these variations.
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RELATED APPLICATIONS
This is a Continuation In Part Application based on U.S. Non-Provisional application Ser. No. 12/391,223, filed 23 Feb. 2009, which is based on U.S. Provisional Application Nos. 61/030,721, filed 22 Feb. 2008; 61/061,318, filed 13 Jun. 2008; 61/129,356, filed 20 Jun. 2008; and 61/073,926, filed 19 Jun. 2008.
BACKGROUND OF THE INVENTION
The present invention is generally directed to a healthcare management system. The healthcare management system includes a framework of databases, proxies, services, processors, a front end Healthspace service Application Programming Interface (API) or Healthspace framework (used interchangeably herein) using a web service and internet gateway to interconnect heterogeneous clients. The system not only interconnects various service providers and clients but also provides methodologies for measuring efficiency and providing incentives, suggestions, and means to improve the performance and efficient utilization of healthcare services by consumers and service providers. Still further, the system provides for relationship based security and methods for increasing effectiveness of communicating healthcare information.
The U.S. healthcare system is the most costly in the world. Healthcare is out of control in America. There are many providers of healthcare who each medications, billing, and claims. Every person has a detailed medical history that could be relevant to future diagnoses and to the treatment of potential problems, yet all of the various practitioners are separate and maintain different records that are proprietary, incompatible, unconnected and generally inaccessible. Health costs are rising and a large portion of this is due to inefficient use of healthcare. Some inefficiencies include the disconnected nature of practitioners and clients, the lack of cooperation between practitioners, the inappropriate use of brand named drugs as opposed to generic drugs, a general apathy on the part of the client and also, in large part, due to lack of accurate information presented to clients or patients. Of the information that is out there and that is indeed broadcast accurately to relevant patients, there is a tendency for these people to just ignore or not be motivated to change their behaviors to increase their health or efficient user of their healthcare benefits. People are inundated with so much junk mail and spam, solicitations, and advertisements that the only way to cope is to block out a large portion of this as noise and unwanted and throw it away or ignore it.
So there exists a need to interconnect all of the different medical practitioners with billing and insurance adjustment, prescription providers, the end-user, client, patient, or consumer, and also to inform them of better practices and effectively communicate with them to motivate them to change behavior to be more healthful and efficient in use of funds, medicines, and benefits. Still further, there exists a need to ensure access to records is constrained solely to authorized entities.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a system and method which provides a framework for practitioners and service providers to serialize, standardize, and provide medical information to authorized consumers and service providers.
It is another object of the present invention to provide a system and method which restricts access to medical records to only the owner of the records and those granted an explicit or inherited relationship of trust with the owner.
It is a further object of the present invention to provide a system and method for interlinking clients or patients with care providers and service providers to facilitate communications, scheduling, and coordination.
It is still another object of the present invention to provide a system and method for monitoring the efficiency of users and comparing them based on benchmarks and by comparisons to their peer groups.
Yet another object of the present invention is to provide a system and method for analyzing how users and service providers increase their efficiency index within the system and communicating this to other users to enable them to similarly increase their efficiency index as well.
It is a further object of the present invention to provide a system and method which segments users to enable one to more successfully motivate and encourage these groups of users to change behaviors or increase their efficient use of healthcare options and benefits.
Another object of the present invention is to provide a system and method which analyzes and optimizes messaging to users to effectuate a change.
These and other objects are attained in a system and method formed in accordance with the present invention for a network based healthcare management system. In an embodiment of the system and method, a healthcare management system is programmably implemented in at least one server apparatus. The server apparatus may be any type of server apparatus known in the art. The server apparatus maintains a plurality of databases of different information, for example physician management, customer service, patient management, communications, prescriptions. Some databases of the system are not maintained in-house, but instead, are brought in as proxies, for example: Aetna Claims Management Database residing on an Aetna server may be proxied in and treated as a virtual database, or a CVS prescription database maintained on the CVS server may be proxied in and treated as a virtual database on the current system. Any known type of database structure may be used.
The information on the databases is retrieved using services either: residing on the external servers of care providers, or on services residing within an in-house server. Rather than provide the end-users, clients, patients, individuals, or consumers (used interchangeably herein) with direct access to the services, a Healthspace service application programming interface (API) is provided with modules such as: client and service registration, service operator (which operates as a marshal), security model, healthcare efficiency index, and Healthspace economy. A Healthspace client or end-user may access the system on their choice of platform, be it a workstation, phone, or PDA through an internet gateway/web service gateway. Additionally, other service providers may also interface with the Healthspace service through their workstations or servers accessing the Healthspace service through the internet gateway/web service gateway.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic block diagram illustrating an exemplary arrangement of nodes of a system architecture within a portion of a hierarchical tree defined in accordance with the present invention;
FIG. 2 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 3 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 4 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 5 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 6 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 7 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 8 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 9 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 10 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 11 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 12 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 13 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 14 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 15 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 16 is a diagram schematically illustrating a functional arrangement of system components in one exemplary embodiment of the present invention;
FIG. 17 is a flow diagram illustrating an exemplary flow of information and data;
FIG. 18 is a diagram schematically illustrating components of a patient's efficiency score;
FIG. 19 is a chart illustrating comparisons of efficiency scores;
FIG. 20 is a chart illustrating principals, relationships and roles;
FIG. 21 is an illustrative example of a display of a graphical user interface of a second application of an exemplary embodiment of the present invention;
FIG. 22 is an illustrative example of a display of predictive model of a graphical user interface of a second application of an exemplary embodiment of the present invention;
FIG. 23 is an illustrative example of a display of a graphical user interface of a third application of an exemplary embodiment of the present invention;
FIG. 24 is an illustrative example of a display of a graphical user interface of an application of an exemplary embodiment of the present invention;
FIG. 25 is a schematic block diagram illustrating an exemplary arrangement of nodes of a system architecture within a portion of a hierarchical tree defined in accordance with the present invention;
FIG. 26 is an illustrative example of a click stream of the present invention;
FIG. 27 is an illustrative example of another click stream of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A network based healthcare management system according to the present invention includes a framework (Healthspace framework) based preferably on a service oriented architecture (SOA) designed to support differing types of applications. As seen in FIG. 1 , the framework provides a plurality of different services, each generally performing an atomic, or discrete, function. A subset of the universe of services is chosen for each specific application. In one embodiment, the application is a healthcare management application, and includes, illustratively, services such as: predictive modeling, claims analytic service, customer service, patient management service, physician management services, communications and messaging services, claims management services, consumer engagement tools, clinical guidelines, and prescription drugs.
Each of the services accesses at least one database that it draws information from and potentially saves information to. Illustratively, these databases include a database of physicians, a database of customer service, patient management database, communications database, prescriptions database, or the like. These databases, collectively called a dataspace, may be maintained on-site on the server, or they may be accessed through a proxy gateway which will treat a database located on an external service provider's server as if it were a local database contained within the Healthspace framework itself. In this manner, the various services that the Healthspace framework provides are able to tie in a heterogeneous mix of different service providers, practitioners, caretakers, and caregivers and the various services may access and serialize their independent, proprietary database formats irrespective of the proprietary formatting and treat the proprietarily formatted data as if it was in a uniform format thereby making it easily accessible through a consolidated, universal network such as the healthcare network of the instant invention. Furthermore, queries are able to be made uniform across these disparate database sources. Not only are the databases able to be located on external service providers servers, but also the framework is able to utilize services that are provided by the external service providers. For example, the framework is able to utilize services residing and provided by an insurance provider or a pharmacy or a doctor's office and those services are incorporated and used seamlessly by the framework of the instant invention.
The framework itself, which may be thought of as the glue that pulls all the disparate services in the Healthspace together, moderating client features and service operations, may be implemented in Microsoft .Net version 3.5, using Windows Communication Foundation (WCF) with a C# (C sharp) language. The framework may utilize Language Integrated Query (LINQ), LINQ-to-Structured Query Language (SQL) and LINQ-to-Extensible Markup Language (XML) to facilitate access to necessary data. Thereby, universal query language may be used to support multiple database types including relational, DB2, and Oracle, et cetera. Windows Presentation Foundation (WPF) may be used to build client applications that will interact with the framework.
The framework comprises several assemblies or code libraries, including, illustratively:
An Hciactive.Healthspace assembly which serves as the main framework assembly. The Hciactive.Healthspace assembly contains utilities and classes used by both clients and server applications in the framework. A set of custom exceptions and exception handling mechanisms are defined to react in certain defined ways to special conditions which change the normal flow of execution. In the event that a supported exception is generated and thrown or reported by a server, it may be converted to a WCF fault to match the IHealthspace fault contracts. There are four general varieties of faults, including: UserInputErrorFaul, SecurityFault, ConfigurationFaul, and a general ServiceFault.
The Hciactive.Healthspace.Services.Database assembly which may include, among other functions, basic database functions, extension methods, and transaction capabilities.
The Hciactive.Healthspace.Services assembly contains the classes needed to register and control client and service operations.
The Hciactive.Healthspace.Services.Host assembly contains the classes that implement the actual WCF host.
The Hciactive.Healthspace.Services.Security assembly contains classes to control authorization of client features and service operations.
The Hciactive.Healthspace.Client assembly contains classes to expose and provide selected features to a client application.
This dynamic framework allows addition of new services, deletion of outdated services, or modification of existing services. To keep track of available services, the framework provides for service registration. Each service is associated with a class that implements the service. Within a service, there may be one or more service operations. The service operations provide entry points to individual transactions or procedures that a service may perform.
Similarly, clients are registered as well. Client registration involves specifying which clients will use the Healthspace framework and what they are allowed to do in the Healthspace framework. Clients are segmented into Client Features; the Client Features are then able to be activated or deactivated based on individual user security, roles, and preferences. Client features are registered with the service operations that they may call such that the security system may properly allow granular access. A client seeking to access a service operation that has not been registered will receive an access denied exception. If no service operations are registered with a client's features, then there are no calls that the client may make without getting access denied exceptions.
Security is based on a combination of both client application features and user privileges. A user may have access to an operation, but the client application may not. For example, a doctor working with a chat program likely has rights to modify a patient's medical records, but the chat program is not designed to do so and does not provide the necessary features. Conversely, a client may be designed to use an operation that the user working with the client does not have privilege to access. As another example, a customer service representative may be logged into a medical records system that has the facility to modify patient records, but the user specifically does not have that right. Therefore, based on client feature registration, and individual user roles, the gateway would restrict access to the service to modify patient records in the two aforementioned situations. On each service operation call, a session token (identifying the user, the client application, and an expiration) should be provided. The framework will check for appropriate permissions before enabling the client to call an operation.
The framework provides a mechanism for calling the many constituent services in a unified and standard manner. Service operations are referenced by name. The service name and the operation name together identify a unique function from the complete list of operations across all services. To allow for flexibility, each service operation is preferably called with a single XML input parameter and returns a single XML output. The single XML input and outputs may be complex data structures containing many values serialized in XML format.
To ensure security and restricted access to files, services, and information, different levels of security, authentication, and certification are employed. For example, end-users and clients, or consumers, are not able to directly access the services or databases that are provided, and instead are insulated through several layers including the Healthspace API, the internet gateway, and the Healthspace client software residing on the end-user's device.
The end-user's device, whether it be a home computer, PDA, cell phone, kiosk, or even a set top box, will have individually written client software which has defined system calls and a user interface defined, for instance, through eXtensible Application Markup Language (XAML) or WPF which defines the limited manner in which the end-user may interface with the client and the Healthspace service API and, ultimately, the services and databases. Deployment services are supplied as an added feature of Healthspace. Client assemblies may be packaged for execution on target environments for one click or (ClickOnce) deployment.
A first layer to preventing unauthorized use is to secure use of the client program by a user name and password, biometrics, or another secure mechanism known to one of skill in the art. After a user has entered a user name and password, or otherwise authenticated himself or herself, the client program authenticates not only the end-user, but also, the client program itself to a remote server by any suitable means known in the art. This may include use of a certificate or checksums or any other such measures. The goal of this is to ensure that the client is an authenticated and certified client program, and not a home-brew client program or a malicious type of unauthorized software, such as a bot. In this manner the healthcare management system is able to regulate the initial system calls coming from the end-user.
Once the healthcare management system client program and the end-user have been authenticated as being an authorized user and client program of the system, the security service of the Healthspace service API provides access to managed features (rights to do something) to an end-user and that client program. Essentially, this allows a specific client program and a specific end-user to perform a certain subset of all tasks. This is generally role based. For example, a consumer, or end-user, is not permitted to prescribe their own medication. Only a physician is permitted to prescribe medication to one of their patients. As another example, not just any physician is permitted to add a health reminder. Instead, only a physician that has a confirmed relationship with the end-user, or patient, associated with the user name and password is permitted to do so.
Still further, there is a bifurcation of the ability to access managed features (rights to do something) versus access of private data (permissions to see something). Access to managed features is preferably role based. For example, a physician may add a healthcare reminder. With the access of private data (permission to see something), access may alternatively be identity based. For example, an end-user associated with a specific user name and password is able to see their own healthcare data, and in certain circumstances, his/her spouse's healthcare data.
Client-Server communication may preferably be implemented in XML. The framework provides functionality through Web Services (using WCF). The Healthspace framework may generally follow an exemplary message loop including:
(1) A Client application initiates a session with a server using the Healthspace web service call including a logon of client id, username, and password to create a session token. The client id may be an identifier of the specific revision or version number of the client application software, or may denote a type of client software e.g. consumer vs. provider vs. administrator.
(2) The client associated with the created session token retrieves an access control list and a client configuration selected to be relevant to the user initiating the session by using the web service to call functions: GetClientFeatureAccess and GetClientFeatureConfig.
(3) The client application displays “client features” to the user based on the user's access (defined by the access control list), preferences, what the application supports, and the client configuration.
(4) For the Client to communicate with a server, the client repeatedly executes “service operations.” The service operations are executed through a web service call: Execute(sessionId, serviceOperationId, XmlParameters). The session id, service operation id, and XML parameters are provided to the call with XML results being returned.
Service operations provide a mechanism for calling the many constituent services in a unified and standard way. Service operations are single stateless method calls with the standardized method signature: public delegate XElement ServiceOperationName (XElement parameters). Service operations are registered with Healthspace to be executed by services running in the context of the server host. Based on the session context, the server determines if the client/user combination may call the server feature being requested. If, based on the session context, the client/user combination is unable to call the server feature being requested, an AccessDenied fault may be generated.
(5) The session is ended with a Logoff.
Member services are shared by all services with the session being stored in a database. The Hciactive.Healthspace.Client assembly provides user authentication, member and session management services. The main class in the assembly is the Session class. Through this class, a client application may log on and log off users. The Session class may also invoke server features through a web service. The main methods of this Session class include: Logon, Logoff, Execute, ExecuteFileTransfer, and GetDataPage.
Additional security is maintained through only providing a few entry points into the framework including:
Logon: Begins a session with the user and a particular client. The client is given a session token which is used with other calls to identify the user and client combination.
ChangePassword;
Logoff: Ends a session with a user and particular client, forcing expiration of the session token;
Execute: Allows a client to interact with services using XML messaging;
ExecuteFileTransfer: Allows a client to interact with services to pass raw binary messaging;
GetClientFeatureAccess: Provides a list of the client features that a user is permitted to use in a session. This is used to enable the client to selectively hide/show elements of the user interface based on their access level.
GetClientFeatureConfiguration: Returns to the client an XML configuration file for a specific client feature. This may be used to allow dynamic form building as well as allowing the user to save preferences.
The Hciactive.Healthspace.Services.Security assembly provides tools to authorize users. This assembly is used by the client applications to grant or decline permissions to certain users based on roles.
A client application may execute remote server functionality through service operations. The service operations are hosted in the server application and are invoked by the client through the Hciactive.Healthspace.Client.Session class (using the aforementioned Execute, ExecuteFileTransfer, or the GetDataPage methods).
To create a service operation, the Hciactive.Healthspace.Services.Iservice interface is implemented. The methods to be exposed should be marked or flagged with the [ServiceOperation] attribute which is preferably contained in HciActive.Healthspace.Services.ServiceOperationAttribute. In order to expose a method as a service feature, it should comply with a signature such as:
[ServiceOperation]
public XElement ServiceFeatureName (XElement parameters)
Such a signature indicates that a particular method may be used as a service feature. As the method signature uses XElement parameters, service features should use LINQ-to-XML XElement objects to receive the XElement input parameters and return values.
For each Execute call of a service operation, the server performs several steps, including:
(1) verifying authorization;
(2) determining the service responsible for the server feature;
(3) creating an instance of the service class through Reflection;
(4) calling configure on the service class;
(5) setting the CurrentSessionContext object (having sessionId, clientId, and principalId);
(6) executing the service method responsible for the ServerFeature;
(7) disposing of the service.
Each service operation should be developed in a “stateless” way. If information or context needs to be preserved between two or more separate Execute calls, the information or context should be stored in a database. Generally, the information or context to be saved between separate Execute calls should not be written in such a way that a first service operation starts an operation, and a second service operation finishes that same operation. Preferably, a single service operation completes the entirety of an operation. Alternatively, an operation may be broken down into multiple states that may be stopped and reconstructed at will. In this alternative embodiment, each of the multiple states should have their own service operation.
A client application may define several client features. A client feature means that the client is declaring that it is going to use a service operation. Client features use Access Control Lists (ACL) to allow or deny access to client features to the specified user. The Healthspace framework has mechanisms to allow a given client application to show or hide graphical elements depending on an ACL.
The web project that publishes WCF services should have the following exemplary configuration in order to register service operations to the framework:
<hciactive.healthspace.services.host SecurityService=“Security”>
<glebalSettings>
</globalSettings>
<services>
<service name=“Security”
serviceType=“Hciactive.Healthspace.Services.SecurityService”
assembly=“bin\Hciactive.Healthspace.Services.Security.dll”>
<settings>
<add name=connection” value=“Healthspace”/>
</settings>
</service>
<service name=“P2PHC.IM”
serviceType=“P2PHC.Services.IMServices”
assembly=“bin\P2PHC.Services.dll”>
<settings>
<add name=“connection” value=“Healthspace”/>
</settings>
</service>
<service name=“P2PHC.Cal”
serviceType=“P2PHC.Services.CalendarServices”
assembly=“bin\P2PHC.Services,dll”>
<settings>
<add name=“connection” value=“Healthspace”/>
</settings>
</service>
</services>
<clients>
<client clientId=“P2PHC.Client”>
<clientFeature name=“P2PHC.Client.IMClientFeature”>
<serviceOperation
operationId=“P2PHC.IM.GetContactList”/>
<serviceOperation
operationId=“P2PHC.IM.SendMessage”/>
<serviceOperation
operationId=“P2PHC.IM.GetNotificationList”/>
</clientFeature >
<clientFeature name=“P2PHC.Client. CalendarClientFeature ”>
<serviceOperation
operationId=“P2PHC.Cal.DeleteAppointment”/>
<serviceOperation
operationId=“P2PHC.Cal.SaveAppointment”/>
<serviceOperation
operationId=“P2PHC.Cal.GetAppointmentList ”/>
</clientFeature>
</client>
</clients>
</hciactive.healthspace.services.host>
<appSettings/>
<connectionStrings>
<add name=“Healthspace” connectionString=“Data
Source=(local);Initial Catalog=Healthspace;Integrated Security-True”
/>
</connectionStrings>
Client applications should define a WCF endpoint in an App.config file like the following exemplary code, where the server name specified in the Uniform Resource Locator (URL) should be where the WCF project is running (where the service operations reside):
<system.serviceModel>
<bindings>
<wsHttpBinding>
<binding name=“WSHttpBinding_IHealthspace”
closeTimeout=“00:01:00”
openTimeout=“00:01:00”
receiveTimeout=“00:10:00”
sendTimeout=“00:01:00”
bypassProxyOnLocal=“false”
transactionFlow=“false”
hostNameComparisonMode=“StrongWildcard”
maxBufferPoolSize=“524288”
maxReceivedMessageSize=“65536”
messageEncoding=“Text” textEncoding=“utf-8”
useDefaultWebProxy=“true”
allowCookies=“false”>
<readerQuotas maxDepth=“32”
maxStringContentLength=“8192”
maxArrayLength=“16384”
maxBytesPerRead=“4096”
maxNameTableCharCount=“16384” />
<reliableSession ordered=“true”
inactivityTimeout=“00:10:00”
enabled=“false” />
<security mode=“Message”>
<transport
clientCredentialType=“Windows”
proxyCredentialType=“None”
realm=“ ” />
<message clientCredentialType=“Windows”
negotiateServiceCredential=“true”
algorithmSuite=“Default”
establishSecurityContext=“true” />
</security>
</binding>
</wsHttpBinding>
</bindings>
<client>
<endpoint
address=“http://ServerName/P2PHC.Web/Healthspace.svc”
binding=“wsHttpBinding”
bindingConfiguration=“WSHttpHinding_IHealthspace”
contract=“HealthspaceServicesReference.IHealthspace”
name=“WSHttpHinding_IHealthspace”>
</endpoint>
</client>
</system.serviceModel>
While the invention of the subject Patent Application provides for very fine-grained setting of access controls, it may not be effective in all applications to individually set and unset each specific permission for each end-user based on each service provider. Preferably, default profiles of relationships are established.
For example, when an end-user or a patient establishes a new relationship with a hospital or a primary care physician, a relationship of trust could be granted by default to the primary care physician and/or their practice or establishment. Therefore the billing departments, the claims adjuster, the other physicians associated with the healthcare establishment or practice may also, by default, inherit access to that end-user's medical records, as well as access to certain managed features. This obviates the untenable process of needing to individually select and add permissions each time a change is made or a new relationship of trust is established with a different practitioner, practice, caregiver or service provider. It should be evident to one of ordinary skill in the art that establishing such granularity of levels of trust on a per-patient, per-service provider basis would not scale well, where many consumers and service providers are to be enrolled. Thus, by using default profiles of established trust, and allowing inheritance of trust, unauthorized access to files is prohibited while still allowing ease of access to those who do genuinely need access to the information.
The invention of the subject Patent Application is preferably operable to manage and capture user access, data access and security rights within a healthcare management network. The core security model of this framework is preferably based on three elements: Principals, Roles, and Relationships. By using these three elements, the framework effectively defines the social interactions between entities within the system and effectively manages data and access security across the framework.
Preferably, the core security model also uniquely models the natural human interactions between entities creating an intuitive “trust” security model allowing entities to inherit data and access rights within the system. This inheritance model also helps to scale system security to many users, because entities may then securely interact with each other through this inherited security model, since each entity assumes its natural security rights based on their role within the system.
Principals are the entities that interact within the system. Principals may be individuals, organizations, or service accounts. This abstraction allows for further flexibility for other principal types, including, but not limited to software agents or clients, healthcare networks, plan design, and other uses that may be defined as an entity and may functionally interact with other principals.
A relationship is a link between two principals. Relationships may be uni-directional between the owner principal and the related principal. The relationship may also define the role that the related principal plays for the owner principal.
For a real-world example: a relationship may exist between a person, John Smith, and his company, ABC Inc. In the system, this relationship would be defined as two relationship records: One record where John Smith is the owner, ABC is the related principal, and the role is Employer; and a second record where ABC is the owner, John is the related principal, and the role is Employee.
Relationships define how trust or security should be defined between principals. This trust relationship is further refined with “roles.” As an example, defined relationships allow for enforcement of privacy rules and regulations such as HIPPA in the health industry.
Roles may define and characterize the type of relationships between two principals. When a principal is associated with a role, the principal is expected to use the characteristics of the role to perform functions within the system. Particular characteristics defined by roles in the system include, but are not limited to: security rights to application features, permissions to interact with other principals, and context-relevant data properties of a principal. An example is a “Doctor” role. Doctors may have access to special software features that are only relevant to the functions of a Doctor role. Doctors are permitted to access electronic medical record modules that other principals may not. Doctors may be able to interact with their own patients in ways that they cannot interact with other principals of the system, such as modifying their patients' medical records and sending medical alerts. Doctors may be afforded properties such as specialty, office hours, and national physician code that are not applicable to other roles.
Some roles are independent of relationships and control the functions or rights that a principal may claim to use. Other roles may be used in relationships. Relationship roles may also have natural inverses. For example, “Doctor” and “Patient” are inverses of each other, which help further categorize and characterize the security between Principals.
Features within the systems may be similar to industry standard definitions of software features; they may define what a user may do with the system. Features are used to specify security and to extend the system. A notable aspect of the present invention is that features may be explicitly named and registered within the system independently of the platform's core.
The full range of features and services may not be defined at design-time. Therefore, the system allows features to be added to the system after the implementation of the platform, for instance, at the time of deployment or even during run-time use. Service Operations that a feature requires for proper operation may also explicitly be associated with features.
Using all the objects together in the security model allows the system to calculate access control lists. These lists are used by the system to check user access to particular service operations from particular clients. Preferably, the above security model is defined with records database systems and other support files in the system such as XML and binary code.
Provision is also made for security of information in transit through encryption by providing secure sockets layer (SSL) or transport layer security (TLS) to provide hypertext transfer protocol secure (HTTPS). Other means to secure the connection, as may be known to one of ordinary skill in the art, may be employed to prevent eavesdropping and man-in-the-middle attacks. This generally assures safe transit from point A to point B.
To ensure that the servers' data store and various databases are secure, servers are firewall protected, having very limited administrator access and only ports that are necessary will be open. Other means, as generally known to one of skill in the art may be employed.
The present invention may also provide for internet communications capability allowing for near real-time exchanges between two or more parties through an on-line connection. This may be useful in allowing end-users, patients, or consumers to chat with healthcare professionals, claims adjusters, practitioners, or other service providers.
As is seen in FIG. 6 , an end-user, for example Jane, could initiate a chat with a registered nurse to find a specialized caregiver. Likewise, and as seen in FIG. 3 , each end-user maintains a list of contacts. The contacts are broken up into specialized categories such as accounts and services which could illustratively include an account management contact, a customer service contact, or a claims manager contact.
Another category may be healthcare professionals which could include a primary care physician, specialists such as an endocrinologist, a gynecologist, or a pharmacist. Another category could be a wellness category including a care coordinator, a dietician, or a personal trainer. An end-user is able to establish contact with any of the contacts on the contact list using any number of different communication methodologies including a chat program, a message program, or any other means, such as Voice Over IP (VoIP) or a video conference.
In the event that a specific contact that is trying to be reached is not available or is not connected, the server will enqueue messages to that recipient and store them on the server until such time as that recipient does log on. When the intended recipient does log on, the server then proceeds to send the queued messages to that recipient.
Each end-user will be provided with the ability to manage their contact list of relevant healthcare services. Included in this ability to manage the contact list is an ability to organize contact for easily initiating communications, categorizing by service functionality or relationship to the end-user consumer.
A goal of this interface is to keep the interface simple and easy to use, such that it may be used by potentially any type of end-user, including the elderly, children, or handicapped individuals. Rather than a more promiscuous-type approach of other social-type networks, the healthcare network of the subject Patent Application is relatively more exclusive in that only contacts that are relevant, or necessary, or that meet certain criteria are allowed to be added as contacts. This will reduce the incidence of spam and unsolicited advertisements and increase a general overall security of the system.
For example, an end-user's ability to simply add another end-user into the contact list is preferably restricted to ensure security and reduce occurrence of unwanted, unsolicited communications. To further security, practitioners or service providers may not be able to simply add individual end-users, or consumers, to contact lists. Instead, the end-user may be required to first add the healthcare practitioner or service provider to the contact list. By having the end-user, or consumer, initiate communication, security is enhanced and spam, or unsolicited advertisement type material, will be restricted, thus allowing end-users to focus more exclusively on more pertinent, relevant, and important messages from authorized service providers. By constraining the contact management and contact lists to be as simple and familiar or intuitive as possible, the effectiveness of the contact list and the healthcare management application in general is enhanced.
Another capability provided by the healthcare management system is alerts. Alerts are messages generally sent between consumers and healthcare professionals or from a professional to another professional.
As is illustrated in FIG. 7 , alerts may be enqueued and presented to a user in a variety of formats including a threaded or a wall-type presentation of tabulated alert events. The tabulated alerts list presents a brief subject, date or time, and a brief excerpt of the subject matter of the alert. A user may optionally activate an individual alert to be provided with the full information on the alert. As is seen, a plurality of different caretakers or service providers or practitioners are able to insert and provide alerts to an end-user to aid them in their healthcare management.
Alerts may be messages initiated by the system itself, for instance as outcomes to rules that check for preconfigured settings. For example, the healthcare management system of the subject Patent Application may be notified or may itself monitor and observe that a new prescription added was for a brand named drug which could trigger an alert to alert the user that a generic drug is available.
Alerts may be enqueued where an immediate response is not required. While alerts may behave in a manner similar to messages, there are differences. For instance, alerts may be constrained completely within the system which would allow for more secure transmission and system tracking. A combination of visual, auditory, or haptic indicators preferably inform a receiving party of the arrival of a new alert. Indeed the entire queue of incoming alerts and/or messages may be tabulated in an incoming wall or a thread, or any other suitable method known in the art.
Yet another functionality provided in the healthcare management system of the subject Patent Application is a reminder function. The reminders may illustratively be requests for action at a specific time or times. For example, a reminder would be used to remind an end-user or patient that there is an upcoming six month checkup that they should attend. Reminders may be set up by an end-user, by a practitioner or service provider, or may be system initiated. A combination of visual, auditory, or haptic indicators may announce to an end-user that a reminder needs attention at a particular time or times. The reminders may be personalized based on the patient's current healthcare experiences. For example: checkups, follow-ups, appointment reminders, or yearly review of claims, any of these may serve as a basis for a reminder. Reminders or alerts may be further customized based on a user's psychographic profile using message ranking methodologies to more effectively communicate with a user.
Message ranking utilizes data-driven or Evidence Based Messaging (EBM) and is used as a mechanism within the Healthspace framework of the healthcare management system of the subject invention to improve the efficiency of messages, alerts, reminders, and communication in general. After segmenting a population of interest using latent class modeling based upon behavioral, psychographic, demographic, etc. data, and being able to accurately classify individuals into segments using a handful of key questions that form a typing tool, it is often useful to study target segments for the purpose of optimizing the effectiveness of messaging or communications. Data Driven Messaging (DDM) is a modeling technique that results in the identification and creation of multimedia (text, visual, audio) communications tailored to the preferences and needs of one or more target segments.
To make the communications or messages more efficient, statistical methodologies are used to compare and select message elements, ordering of content, imagery, colors, audio-visual content, and the selection of supporting materials to be the most effective for a given segment. This helps alleviate the inherent problem of messages being ignored, misconceived, misunderstood or misinterpreted.
Initially, a statistical design for a question is created. The design results in multiple sets of cards, each card representing a group of questions to be asked of a respondent. For example, a question may be: Which of the following attributes of a physician do you consider to be the least important and which do you consider to be the most important?
The results of a Maximum Difference Scaling (MDS) question are prepared and analyzed. The resultant data produces a scored list of attributes. The scores are such that if the attributes were chosen at random to be most important and least important, all attributes would have a score of 100—the average score. Scores below 100 are therefore interpreted as having below average importance, while scores above 100 have above average importance. The farther a score is above 100, the more important it is. This methodology will thereby provide a relative ranking of attributes, and a pseudo-absolute rank scale of attributes. That is, if one attribute is ranked as most important, the magnitude of the difference between its score and the next highest score reveals how much more important the one attribute is. As an example, being board certified (score=210) is the most important physician attribute to the sample of respondents, but it is not much more important, if at all, than the physician having evening hours (score=200).
This allows for leveraging segmentation results to isolate homogeneous groups within a population, allowing for further segment-specific research, for example: data driven messaging. A further benefit is that effective communication is achieved such that information relayed is clear, understandable, and as believable as possible, towards the goal of convincing an end-user to adopt suggestions, change behaviors, or be mindful of potential issues.
For example, a segmentation could be performed on patients with diabetes if a health plan wanted to improve treatment compliance among members of a segment that were not managing their diabetes well and were at risk for complications. Data driven messaging, in the context of the health care management system, would enable the testing and refinement of a variety of differently tailored messages, specific to each segment, optimizing the language used to explain the risk of non-compliance, descriptions/graphics/images of potential complications, amount and quality of technical information ranging from broad descriptions/generalizations in lay terms/articles from medical journals or graphical presentations of clinical data.
Continuing the Diabetes example: Data driven messaging will provide quantitative evidence of elements of messaging such as, what information needs to be communicated, how information must be communicated, and in what sequence it needs to be communicated in order to optimally motivate the target segment of diabetes patients to: increase treatment compliance, reduce the risk of complications, increase their health efficiency index, lower the cost of their healthcare, and reduce number of sick days, etc.
Prioritizing message order allows for getting the subjectively most important factors or elements of a message to a particular segment first to thereby securely capture readers of the particular segment such that they will understand and be motivated by the entirety of the message. For example, where it has been established through results of the maximum difference scaling questions, that one attribute is most important, this attribute may be emphasized and displayed most prominently. Still further, the relatively less important attributes may be communicated in their respective relative order of import to maximize impact. For example, if three elements of an insurance plan were found to be crucial to the plan's adoption: cost of the monthly premium, immediate access to specialists, and $10 Rx copays. One segment considering plan adoption may rate all three items as necessary in their choice of a plan, but may prefer to know about the costs of the plan up-front. On the other hand, these three plan attributes may be equally important to another segment which is also cost-sensitive, but be secondary to the option of having immediate access to specialists. If this information is known, the order of the message elements may be adjusted to maximize impact.
Still further, this data driven methodology allows for minimizing distractions or noise created by communications that are unclear or ineffectual. With data driven messaging, potential communications are tested, results analyzed, and then optimized to appeal (in terms of preference, motivational power, clarity, etc.) to a targeted segment. This form of sending tailored messages with calculated content fosters acceptance of messaging, reliance thereon, changed behavior, and ultimately, a more efficient healthcare system.
This data driven messaging methodology may be applied to all messages sent by the system including customer service, physician management, evidence based medicine or clinical protocol management, medical management, disease management and behavioral health management.
As an example: in medical management, utilization review and case management: patients with complex medical conditions, co-morbidities, multiple doctors and medications require not only review and coordination of care, but also constant communication between the case manager and physician, case manager and patient, and physician and patient. Giving the case manager insight into the communication style and content hot buttons of the physicians and patients they are coordinating will improve coordination and teamwork of all parties involved in a particular case.
As another example: in evidence based medicine or clinical protocol management—reviews of claims and treatment history may reveal whether standard protocols are being followed in the care of individual patients both with acute or chronic conditions, and when it comes to preventive medicine recommendations. Once this information is gathered on the back-end, suggestions and/or intervention messages are sent to the physician and/or patient. Informed communications through data driven messaging help create messages that are more likely to be acted upon, thus improving health.
Still further, physicians may be segmented, with target segments studied and targeted using data driven messaging techniques to improve patient care, increase efficiency, help align treatment protocols most closely with current standards of care, etc.
As seen in FIG. 8 , another functionality the healthcare management system provides is calendaring. The healthcare management system of the subject Patent Application preferably maintains customized calendars for each end-user. Reminders and alerts are tied in to each end-user's calendar. Each end-user is able to populate their calendar with important healthcare related events, dates, or appointments. Also, service providers may be able to input events to a user's calendar. Each end-user's calendar is a personalized calendar, being personalized based on the patient, and focused on healthcare related appointments or events. The calendar illustratively lists appointments or highlighting of time-critical messaging including doctor's appointments, medication refills, or drug-to-drug interactions.
At a service provider level, the healthcare management system provides for assistance with coordination to avoid schedule conflicts. The assistance may be in the form of notification, reminders, or alerts of scheduling conflicts or of upcoming scheduling appoint type events. Preferably, caretakers, service providers, and other authorized users could input events and/or reminders to a user's calendar automatically and without requiring the end-user or patient to perform anything. Alternatively, the client or end-user could be given a chance to authorize or deny service provider's proposed additions, subtractions, or modifications to that end-user's or other authorized accounts' calendars.
In an illustrative view displayed at a user interface, an end-user, patient, or consumer may add a physician to her network, including the physician in their contact list, and then contact a care coordinator to secure an appointment with a new physician. A caretaker could then populate the consumer's calendar with the appointment and all relevant information which could trigger corresponding alerts and/or reminders to the user.
Preferably, there is a specific or customized view presented for one type of end-user such as a patient, or consumer, and there are alternate views presented for differing types or species of end-users such as a caregiver, human resources personnel, or claims adjuster. The type of interface is determined by the type of user, potentially being role-based, so there is a correlation between a type of user and a type of interface that will be presented to them.
Illustratively, there are two main types of users: consumers and service providers. Consumers will generally view only their own information and manage their own interfaces. However, there may be exceptions where a consumer is able to access another consumer's data and manage their calendar, alerts, reminders, or contact list. This could generally be provided for a husband accessing a wife's data; a wife accessing a husband's data; or in the case of parents: accessing and managing their childrens' data. Some illustrative examples of consumers' views could be a patient/employee view, an employer view, or an out-of-network health service provider view.
While consumers generally view their own information, service providers may be able to manage the information of consumers or other service providers. Some exemplary service provider views could be: a customer service representative view, an account services representative view, a care manager view, an executive/system administrator view, or an in-network health service provider view. Some service providers may not be provided with access to any particular consumer's data, and instead are provided only with aggregate or abstracted data.
Still further, consumers or service providers may be provided with a default view or a universe of potential views of information or functionalities, and the consumer or service provider is able to customize the view utilizing a subset of the available information or functionality that they are authorized to access.
A customized view, as seen in FIG. 21 , prepared for administrators using aggregate or abstracted data may be implemented with another client program using the Healthspace framework API, as part of the health care management system, such as Active Reporting Service (ARS), which organizes and evaluates pharmacy and medical data and combines management, measurement, and administration tools on the front-end within the confines of the Health Insurance Portability and Accountability Act (HIPAA). ARS allows management or administrative staff to receive pertinent information to identify problems and find custom solutions that will lead to alternatives, choice and competition by looking at aggregate health benefits information for groups relevant to the particular administrator or manager. ARS provides for live plan performance; real-time plan simulation; actionable turn-key outreach, measuring results and making adjustments. This allows for a collaborative environment where a plan administrator/manager, consultant/broker, and account management team work together to find key health costs and condition metrics, analyze this data and interpret to simulate plan changes and estimate costs, plan Return On Investment (ROI) models, and utilize trending information to measure the effects of program changes and see how a health program is developing over time.
Another functionality that the subject Patent Application provides for is an information portal which includes a research tool to look up trusted healthcare resources in exploring various healthcare concerns. Still further, a consumer is able to view their claims history or an aggregate reporting of healthcare usage, or even further, access a predictive modeling or health risk assessment library or information knowledge base.
A healthcare efficiency rating or scoring functionality is provided to display an efficiency rating or score of an individual based on their healthcare decisions and participation. This rating or score is compared to bench marks or peer groups, as defined by the individual consumer's peers at a place of employment or based on peers decided by factors such as age, sex, body biometrics or even fellow patrons of a particular service provider. The Healthspace efficiency index, rating, or scoring is utilized to maximize health benefit utilization or maximize healthy living or wellness or maximize treatment plan adherence and compliance. The Healthspace efficiency index is used to incentivize or penalize consumers (or even, potentially, service providers) towards certain kinds of behaviors.
Preferably, a consumer's user interface has a portion of the screen devoted to prominently displaying the efficiency index which prompts them to click on it which explains to the consumer that the efficiency index helps a particular consumer understand how to better improve their quality of life and better manage their cost of care. Illustratively, the user is presented with expert recommendations from their healthcare touch points or contacts to help them maximize their health benefits.
An exemplary way of doing this is that the user is presented with an alert from a pharmacy benefit manager stating that the consumer's recent visit to a practitioner resulted in a prescription of a brand named drug, and that switching to a generic drug could save the consumer money and increase their efficiency index. To motivate the user to increase the efficiency index, certain incentives may be provided, for example: the consumer may be provided with a zero co-pay for the first month. Accordingly, and as seen in FIG. 11 , a user's claims history is preferably presented to them, along with an efficiency index.
Providing the user and administrators with an efficiency index allows for quantitative analysis of plan utilization customized to the specific population. This allows plan administrators to identify weak points in coverage, compare their plan with other plans (as applied to their users), and identify areas of potential savings based on the plan document. Potential savings could be based on generic pharmacy availability, pre-certification requirements, or matching in-network doctors with specialties. The efficiency index enables the plan administrator to identify an overall plan spectrum or fingerprint, quantitatively evaluate plan performance, and create customizable suggestions. This wealth of information may be used to target excessive denials from particular exclusions which results in high costs including increased absenteeism and detriments to users' health. Further, marketing opportunities become apparent to administrators when viewing efficiency information in the aggregate. Based on the quantitative analysis, an administrator is able to restructure the plan accordingly to further optimize costs and benefits according to their unique group of users. Not only are administrators able to optimize the plans, but individual users are able to monitor their own efficiency indices and change their behavior to be more healthy and save money.
As seen in FIG. 12 , the efficiency index, or rating is presented to the user and were the efficiency index or rating not acceptable to the user or if the user desired to increase the efficiency rating, the user may be prompted to follow expert advice. For example, as seen in FIG. 13 , the user is presented with an alert from a service provider advising them of a course of action to improve their efficiency rating.
As seen in FIG. 14 , by clicking or activating an alert, the full text of an alert message is provided to the user. The text or multimedia including audio, video or other methods is customized and tailored (as discussed supra) to a specific user or to a class of users to be more likely to motivate a change or to get the user's attention. As is seen in FIG. 15 , the expert advice could come by way of alert, or reminders, or events contained in the consumer's calendar.
The Healthspace efficiency index is effectuated by providing a scoring method of categorization and metrics, calculating bench marks, and by providing a change agent. The scoring method by categorization and metrics includes defining categories as collection of metrics or key performance indicators (KPIs). Categories include any or all areas of healthcare benefits including claims, utilization, risk profiles, predictive modeling, care management intervention, statistical models, evidence based medicine, or any healthcare related category that could be objectively measured.
Comparative risk profiles, medical or pharmacy claims, adherence to evidence based medicine, health or pharmacy benefit utilization all provide factors towards the scoring of the efficiency index. As the system is an inclusive healthcare management system bringing together service providers with consumers, a wealth of information is available in the aggregate for analysis and statistical processing to arrive at efficiency indices. FIG. 22 shows an exemplary predictive model utilizing Johns Hopkins Adjusted Clinical Groups (ACG) software to forecast risk and financial information as well as classify patients into different condition categories based on healthcare claims information.
Metrics or KPIs are measures of healthcare utilization or behavior unitized into numeric values, scores, or points. Illustratively, in a category of pharmacy benefits, a metric could be that a patient is utilizing a multi-source brand-name drug. This metric could potentially have 60 points assigned to it. Because this multi-source brand-drug has a generic equivalent, the patient might only receive 30 points for compliance and 0 points for failing to use a generic equivalent. In this example the metric could be combined or separated into individual components. In other words, the consumer could be provided with some points for following a doctor's advice, but even more points, for using a generic drug when one is available, and fewer points for using a brand-named drug when a generic is available. In aggregate, by the accumulation of these points, a user's efficiency index reflects the aggregate of the user's efficient utilization of certain categories of their healthcare benefits. Thereby, consumers' choices are capable of being monitored and incentivized or penalized towards a more efficient utilization of the healthcare coverage.
The numeric value, score, or points in the metrics or KPIs are weighted statistically or modeled statistically to improve the performance of the efficiency index.
In the calculation of benchmarks, every individual may be scored individually so that a total efficiency index, preferably a percentage, or score may be given to that individual. The individual score is then compared to the individual's peer groups' score or the scores of individuals of the same group. For example, an individual may be an employee and a peer group may be the average score of all the other employees of the same employer group. Alternatively an individual may be compared to everyone in their same age bracket and sex band.
A peer group may be scored and compared to other peer groups. For example one employer group achieving 80% efficiency rating may be compared to another employer group achieving 50% efficiency rating. The formula or calculation of the total score may be calculated by the total points achieved divided by the total achievable points for an individual. This score may be weighted and/or changed using other statistical models for other calculations, for example: forecasting costs if efficiency is improved.
With the aggregation and interconnection of records and service providers and consumer information, comes the ability to statistically measure and arrive at efficiency indices. By providing inefficient users of the healthcare benefits package or healthcare management system with a relatively lower score and by providing suggestions and incentives, it is seen that the consumer is empowered and motivated to raise their efficiency index. In doing so, they raise their efficient use of the healthcare benefits and the healthcare management system and lead a more beneficial, healthy life, while at the same time, save money for the insurers, caregivers and other service providers. Thereby, the cost of insurance and of providing care is reduced. This reduction in costs would not only pass on to the shareholders of those institutions, and to caregivers, or service providers, but ultimately passed back to the consumers themselves.
To effectuate this change, a change agent is provided. Through the combination and consideration of both scoring method and benchmarking, the healthcare efficiency index change agent gives corrective action suggestions (which may be customized or tailored to the individual consumer to be most effective) and/or recommendations to improve the overall efficiency of consumers. This may be applied to caregivers or service providers to help them become more efficient. To facilitate this, consumers are given individualized scores for categories and metrics and also given corrective action suggestions or recommendations to change or improve their respective scores. As soon as the system receives the updated information the scores are automatically updated.
Incentives may be used to help promote and change behavior of the patient towards more efficient use of healthcare. For example, some incentives may include zero co-pay for using a generic prescription, or lower deductibles and better rates for utilizing one method of the benefit plan over another. Indeed, any suitable incentives may be used.
It can be seen in FIG. 18 that the patient healthcare utilization records of prescription, claims and assorted data are harvested as input into the total efficiency score calculation by decomposing into category scores and assigning weights to each category. By using KPIs and metrics to aggregate data on an individual consumer, suggestions may be correspondingly made. As seen in FIG. 18 , a consumer or user, or even a service provider, may be allowed to view the calculation method, factors, or the relative weight of each category to have more bearing on the overall efficiency score and thereby selectively choose fields in which to improve or follow suggestions by which to receive incentives. FIG. 19 illustrates a patient score being compared with an average score of a selected peer group.
While some consumers will be hesitant, apathetic, or resistant to following suggestions to improve their efficiency index, the healthcare management system, through various techniques, such as surveys or risk assessments or questionnaires, is able to segment users into different segments, different segments of users tending to respond similarly to certain stimuli. Each segment may then be strategically targeted with narrowly tailored messages or stimuli.
For example, the universe of consumers may be segmented into different segments based upon behavioral, psychographic, demographic, or other data through the use of questionnaires or typing tools or any other methods to more effectively target that segment of the population. For example, it can be seen that potentially one segment of users may respond well to a short message explaining the effects of a preferred approach whereas another segment may prefer to see (and be more likely to respond to) empirical evidence, research, and actual case studies. Thereby customized messages may be sent to different segments of the population to encourage them to follow suggestions of an efficiency index program to increase their efficient utilization of the healthcare management system or the benefits package to which they subscribe.
Click Operations or ClickOps are another methodology for effectively reaching a low efficiency user to assist them to improve their efficiency. ClickOps is able to provide a means to track the actions that users perform in the system. These actions can be analyzed to search for desirable patterns of action that may lead to, or be correlated with, a high user efficiency.
Users monitored by ClickOps could be any user or provider of healthcare. ClickOps may be implemented by having the system track all actions by recording a “clickpoint” which is a log of a user interaction, or transaction, or transaction that relates to a user. Health plan activities, actions, and user activities or actions are independent clickpoints. An illustrative list of potential clickpoints include: any user action in the system, any user access of the system, claims data, a related clinical protocol, an assignment/capture of evidence based medicine data, a trigger or alert, an appointment, financial information, or other healthcare-related data point. “Clickstreams” would then include a series of individual clickpoints, including dates and times of the users while they are online on the healthcare management system. This allows the system to capture and analyze user behavior and component use within the Healthspace in aggregate.
By way of example, focus may be placed on the users who have an increasing efficiency index or are at a high efficiency index. By studying the actions of users with an increasing efficiency index, a template or suggested pattern or course of conduct may be suitably formulated through the aggregate study of such users and their clickstreams. This model of corrective action may then be suggested through the messaging efficiency tools described herein to effectively convey to different segments of consumers recommended methods for raising their efficiency index. Not only are individual users able to be provided with suggestions to increase their efficiency index, but also Click Operations allows the capture and analysis of care protocols and clinical guidelines.
Information derived from click stream analysis of both employees/patients and healthcare professionals gives feedback on health efficiency in several important areas, including: user health, healthcare professional performance, plan performance, and Healthspace performance. In previous systems, this type of data, if it even exists, is qualitative at best, and the lack of solid information is one source of financial waste in healthcare.
Clickstreams may reveal what components of a healthcare social network, platform, or system, such as Healthspace, are being accessed, the frequency of access, the order of access (i.e. is there a typical flow?), and which healthcare professionals/service areas are using Healthspace. Conversely, clickstreams may also reveal which components are rarely or never used.
The efficiency or effectiveness of a clinical pathway within Healthspace is able to be analyzed and suggestions or conclusions may be observed from the aggregation of different users' pathways. The click stream and pathway of the efficiency index is able to be analyzed. Administrators are enabled to analyze the click stream and pathway of care protocols and clinical guidelines to make judgments on effectiveness. The ultimate impact of a particular clinical pathway or user behavior as related to financial impact is able to be evaluated. Click Operations analysis may also be fed into a pay for performance system, allowing metrics and analysis of healthcare provider services.
Taken further, statistical analysis of clickstream data, in aggregate, may inform or identify: the best, or most widely used services, features, functions, and products of Healthspace; which features, functions, products are frequently combined; Return On Investment (ROI) based upon usage data of elements or combinations of elements within Healthspace; elements of Healthspace that should continue to be offered versus those that should be dropped. Usage that results in modified (i.e. more healthful) behavior among users and usage that results in higher plan efficiency (e.g. what services, features, functions, and products encourage users to switch to generic drugs, or become more compliant with treatment plans) may be ascertained. The user behaviors that affect users' claims history, and ultimately, financial impact on the plan are able to be analyzed. The efficacy of health plan programs, services, features, functions, and products in increasing efficiencies and ultimate cost savings are able to be analyzed through the ClickOps. Still further, ClickOps facilitates analysis of user financial incentives for increasing efficiency index through health-related behavioral improvements (e.g. weight loss, smoking cessation, etc.).
Not only are consumers'/clients'/patients' clickstreams able to be analyzed to improve the efficiency of the system, but also healthcare professionals' clickstreams are able to be analyzed to provide insight, and ultimate improve the system as well. The ClickOps system is useful in identifying best practices from comparisons between actual medical protocols versus those provided by an “expert system” such as the VA Health System. In other words, comparisons are able to be made between actual clinical protocols versus the accepted “best practice” protocols. This may provide insight on extraneous health spending, reduce unnecessary tests or procedures, and identify gaps in care. A similar comparison is able to be made against evidence based medicine protocols. The financial impact of a clinical pathway and resulting claims history on a plan are able to be assessed.
Best practices are able to be identified by analysis of claims processing and financial results click streams. For example: which alerts and health-related interventions result in modified patient/physician cost-containment behavior. Moreover, given certain plan or healthcare professional interventions, the percent efficiency or cost savings of a behavioral change is able to be ascertained. As a specific example: if a physician writes a patient a prescription for a drug, for which there is an equivalent generic, an email alert may be automatically sent to the patient advising them that an equivalent, but less expensive, generic medicine is available. This may result in a calculable and perhaps statistically significant increase in the percentage of prescriptions filled with a generic versus those filled with a generic by patients not sent an alert. It may also be found that if a case manager follows-up with a phone call after the alert to personally explain and assist the patient (who has not yet done so) in switching to a generic medication results in a larger, and statistically significant, percentage of patients who use a generic. A plan or employer may find that the additional cost of such proactive educational measures is an effective way of containing cost and increasing healthcare efficiencies.
Support for Pay-for-Performance systems are also incorporated. Production of data based upon click points or click streams that enables quantitative tracking of healthcare successes enables performance-based pay to healthcare professionals for the services they provide. For example, smoking continues to be a high-risk behavior, yet traditional health reimbursement plans often do not compensate physicians for advising and assisting patients to quit. A physician who consistently provides smoking cessation services and communications to patients, resulting in successful quit attempts is able to be tracked with ClickOps and the physician may be compensated according to his/her efforts and outcomes.
FIG. 26 shows an example of a clickstream; the clickstream includes four distinct click points. The vertical axis on the clickstream represents percent participation for each click point. A series of click points are identified along the horizontal axis, comprising the clickstream. The exemplary clickstream represents data from a subset of health plan participants who use one or more maintenance prescription medications. These participants have been prescribed a medication to be used for longer than 90 days. The four click points in the example are: (1) email alert that 90-day supplies of medication are available for a lower cost via mail-order; (2) email alert that a generic equivalent medication is available; (3) usage of an automated refill scheduler that provides refills via phone or email authorization; (4) concierge service that coordinates generic switches with physicians.
Statistical analysis of the clickstream shown in FIG. 26 reveals that email alerts regarding 90-day mail-order supplies and available generics are sent to a statistically significant number of high efficiency plan participants as opposed to low efficiency plan participants. The recommendation to the plan is to require all participants to receive such alerts to drive efficiency.
It may also be seen in the example clickstream that no significant difference in the usage of an automated refill scheduler is seen between the high and low efficiency plan participants. However, a large proportion of participants use this service. The recommendation to the plan may be to continue to offer the service because it is widely used by participants and not costly.
Still further, from analysis of the exemplary clickstream of FIG. 26 , it can be seen that low efficiency plan participants are significantly more likely to use the concierge service for getting physician authorization to generic switches, whereas the high efficiency users are not. This service does not correlate with increased efficiencies. The recommendation to the plan may be to discontinue this service as it is costly and requires personal intervention, while not providing an increase in efficiency. A plan administrator may instead focus resources on helping the low efficiency plan participants to get their maintenance medications via mail-order and alert them about switching to generics.
FIG. 27 shows another example of a clickstream leading to different interpretations. The clickstream relates to treatment and care of a group of patients with diabetes. The click points represent: (1) 6 month primary care physician (PCP) check-ups, (2) annual endocrinologist visits, and (3) no-cost blood sugar testing supplies.
Statistical analysis and interpretation of this click stream reveals that plan participants with diabetes who are high cost patients do not regularly have 6-month PCP check-ups or annual endocrinologist check-ups. High cost could equivalently be related to higher numbers of inpatient days per year (as revealed from claims data), higher risk scores when assigning plan cost to these patients, and more. Clickstream analysis therefore enables employers, health plans administrators, patients, and healthcare providers to effectively assess cost, risk, efficiency, compliance, or any other type of metric that may be measured.
An underlying part to such analysis of a clickstream is identifying who is a high efficiency plan participant and, conversely, who is a low efficiency participant. FIG. 27 illustrates patient participants, but also, healthcare professionals could be classified as high and low efficiency users of a healthcare social network or system.
A variety of methodologies may be used to rank efficiencies, costs, or risks of users, including: hard thresholds (e.g., at or above 50% efficiency is a high efficiency user, whereas, below 50% efficiency is a low efficiency user); thresholds based upon the number of standard deviations from the mean of a given population (e.g., low efficiency users have efficiencies on standard deviation below the mean efficiency, moderate efficiency users have efficiencies within one standard deviation of the meant, etc. . . . ).
The statistical methodologies of ClickOps analysis may include: Confidence intervals, Z-tests, T-tests, chi-square tests, or other methods for determining differences between groups. Here, results obtained from independent groups may be compared, and it may be determined whether the groups are significantly different, based upon a particular confidence level.
1. A T-test may be used to compare a sample mean to a population mean:
a. t=(x bar −μ 0 )/(s/sqrt(n)), where x bar is the mean of the sample, μ o is the mean to which the sample mean is being compared, s is the standard deviation of the sample, and n is the sample size. For a given t-value and confidence level, statistical significance may be measured.
2. A Z-test may be used to compare two independent samples, with a population in which the standard deviation is known for a given value
a. z=(x−μ)/(σ/sqrt(n)), where x is the score to be standardized (compared), μ is the mean of the population, σ is the standard deviation of the population, and n is the sample size. Again, for a given z-value and confidence level, statistical significance of a value is able be determined. b. z=(phat 1 −phat 2 )/sqrt[phat×(1-phat)(1/n 1 +1/n 2 )], where phat 1 is the sample proportion of group 1 (x 1 /n 1 ), phat 2 is the sample proportion of group 2 (x 2 /n 2 ), phat is the weighted average of phat 1 and phat 2 [(x 1 +x 2 )/(n 1 +n 2 )], x 1 and x 2 are the observed values, and n 1 and n 2 are the two sample sizes. After calculating this z-statistic, one is able to determine whether the two observed values are significantly different given a certain confidence level.
Another functionality provided by the healthcare management system of the subject Patent Application is a way for users to bookmark items of interest allowing them to easily recall and find items or objects that are particularly relevant or will be needed in the future. These items or objects of interest may include websites, contacts, informational resources, alerts, reminders, suggestions on increasing efficiency index. These bookmarks are then available for sharing with other consumers or service providers. This allows for the verification by service providers of the accuracy, or the applicability, of a bookmarked item to a particular consumer.
While the healthcare management system seeks to interface caregivers or service providers and consumers or users, and also make readily available resources such as information and contacts and suggestions, another feature is to restrict some information and some resources to be more context sensitive. For example, when the user searches for doctors, rather than providing the user with the entire universe of doctors, a context sensitive list may be provided. For example, when a consumer searches for a list of doctors, preferentially doctors that are in-network could be provided first or even at the exclusion of out-of-network service providers. By providing these in-network doctors or service providers first or exclusively, a user or consumer is quickly able to find an in-network solution that will save them money and will also potentially save the insurance provider money as well. This allows the removal of much uncertainty in the process of selecting a caregiver. Were one simply to conduct an open search for doctors, there is a high probability that a user or consumer ends up with a doctor that is out-of-network and thereby incurs potentially great and unexpected costs. With the aggregation of vast amounts of information, the system is able to be context and location aware.
For example, generally a user searching for a doctor might want a doctor to be proximate to either their home address or their work address or another address that they frequent. This may be accommodated quite easily as the system already knows the consumer's home address, work address, or any other address that the user has input into the system. As a matter of convenience, the system may also provide service provider ratings and reviews or other research, such as a service provider's efficiency index.
As it provides a trusted portal, the healthcare management system also provides look-up information on drugs such as interactions, contraindications, or side-effects, thus allowing the user to avoid or catch potential interactions, side-effects or problems that could arise, in advance. A user/consumer may even be provided with information relating to gaps in care using evidence based medicine or other approaches. Indeed, a broad variety of self-serve healthcare research tools are provided that will improve the health of the consumer. For example, a medicine cabinet feature is provided that lists the consumer's current drug regimen/claims and offers potential equivalent therapeutic alternatives, perhaps at lower costs. It is important to note that each such feature would need prominent disclaimers to inform the consumer that only their doctor may change their prescription. Nonetheless, a potential equivalent therapeutic alternative of interest to a consumer may be bookmarked and shared with that consumer's doctor for their input or consideration.
Each consumer or service provider is provided with a profile. Each profile has various management tasks associated with it that a consumer or service provider would be authorized to change, pursuant to their security authorizations based on relationships of trust or their user name and password. A personal profile preferably describes basics related to healthcare services including demographics, insurance plan reference, dependents list or other such characteristics of a consumer or service provider. In this section the user may manage the application settings or the client software program settings on their platform.
The healthcare management system of the subject Patent Application provides for a developer network or an application programming interface (API). This developer network API allows external service providers a standard platform to access and extend the applications. By allowing external service providers such as insurance companies, physicians, hospitals, and pharmacies to extend the applications and services and access data this, the utility of the platform to the service providers is enhanced by making it easy for them to integrate with and connect with not only their current consumers but also a large numbers of potential consumers. This saves the external service providers time and money by obviating the need to create their own application to interact with consumers and potential consumers. This in turn allows for easier adoption of their services.
However, in allowing the extension of applications there is an increased potential for compromise of security. To counteract that threat, a multi-level certification process to ensure patient security and privacy is enacted whereby only trusted external service providers are able to extend applications. As a further precaution, each application or extension provided by each external service provider is subjected to review and certification by the administration of the healthcare management system or independent auditors.
To facilitate the ease of use by consumers, the client software program for each platform is preferably delivered through the web, being distributed and executed in a trusted host or “sandbox” environment. To allow for the greatest universe of potential users, a simple access-and-use methodology is adopted. Keeping the interface simple and intuitive in this manner enables all users including the elderly or children or the handicapped to more conveniently access and self serve.
Automatic version updates are feasible with limited or no elevation of host access rights or user intervention. In other words, the upgrading process is relatively automatic in that, by using the web for application delivery, the user is able to simply authorize the upgrade and the system is able to do the upgrading automatically. For example, this may be accomplished through a browser-based application or “click once” deployment.
Clients access the application data preferably through the web services which are designed to allow access of client programs from multiple platforms. The services don't need to be rewritten for each independent platform but instead are abstracted, and only the client program is written for each individual platform. The services will access a centralized server or server farm that is a portal to data. However, it is important that the database back-end be isolated from direct public access and provisions are made that databases are only accessible through services called through certified client programs. User's machines have a trusted client program installed and the back-end database is secure. To ensure that the paths therebetween are reliable and private, secure channels are established between the client and the server which are both encrypted and username/password protected.
Another benefit flowing from this abstraction and separation of the back-end is that the back-end database portion is able to integrate with other standard healthcare applications including account management, claims management, predictive modeling, health risk assessment, care management, and the like. To facilitate this, the system employs industry standard data warehousing techniques to store data in de-normalized multidimensional structures that allow for efficient performance for analysis and reporting. FIG. 23 illustrates another exemplary client program built on the Healthspace platform.
These functionalities are able to be extended through the use of strategic partnerships and the integration of other external service providers allowing external developers to extend the client interface with additional services or integrate with additional back-end systems or create clients on additional platforms. For example, as seen in FIG. 24 , the “Medicine Cabinet” tab utilizes Destination RX's web service as a virtual database. The Healthspace platform sends a query to the Destination RX web service and receives back information such as: days left of prescription, refills available, generic alternatives, instructions, costs, and cost savings.
Although this invention has been described in connection with specific forms and embodiments thereof, it will be appreciated that various modifications other than those discussed above may be resorted to without departing from the spirit or scope of the invention. For example, equivalent elements may be substituted for those specifically shown and described, certain features may be used independently of other features, and in certain cases, particular combinations of flows or processing steps may be reversed or interposed, all without departing from the spirit or scope of the invention as defined in the appended Claims.
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A network based healthcare management system is provided. The system includes a plurality of client workstations and a plurality of healthspace service processors. The healthspace service processors access at least one database remotely disposed relative to the client workstations with the healthspace service processors providing access to predetermined healthspace resources. The system further includes a healthspace service interface unit operably coupled to the client workstations and healthspace service processors to selectively actuate at least one of the healthspace service processors responsive to the client workstations. The healthspace service interface unit including an efficiency module which adaptively maintains a plurality of parametric indicia with respect to optimum healthspace resource utilization.
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This application is a 371 of PCT/SE95/00824 filed Jul. 3, 1995.
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a process for the hydro-genation of a substrate, where hydrogen gas is mixed with the substrate in the presence of a catalyst and the reaction is carried out at certain reaction conditions of pressure, time and temperature. The hydrogenation reactions are mainly related to the hydrogenation of carbon-carbon double bonds (C═C) in lipids;
hydrogenation of COOR to C--OH and HO--R for the manufacturing of fatty alcohols; and the direct hydrogenation of oxygen to hydrogen peroxide.
BACKGROUND OF INVENTION
C═C in lipids.
The annual production of vegetable oils is about 90.million tons (Mielke 1992), of which about 20% are hardened (hydrogenated). Furthermore, about 2 million tons of marine oils are hydrogenated yearly. The production is spread over the whole industrialized world. Through the hydrogenation, hydrogen is added to the double bonds of the unsaturated fatty acids. The largest part of the oils is only partly hydrogenated. The desired conditions of melting and the desired consistency of the fats are thereby obtained, which are of importance for the production of margarine and shortening. The tendency to oxidation is reduced by the hydrogenation, and the stability of the fats is increased at the same time (Swern 1982).
In the future, the lipids may be modified by methods belonging to bio technology, especially gene technology, but hydrogenation will certainly remain.
A problem with the hydrogenation processes of today is, that new fatty acids are produced which to a great extent do not exist in the nature. They are often called trans fatty acids, but the double bonds change position as well as form (cis-trans) during the hydrogenation (Allen 1956, Allen 1986).
As a rule, trans fatty acids are desired from a technical and functional point of view (Swern 1982), but regarding health, their role is becoming more and more questionable (Wahle & James 1993).
A typical state of the art reactor for hydrogenation is a large tank (5 to 20 m 3 ) filled with oil and hydrogen gas plus a catalyst in the form of fine particles (nickel in powdery form). The reaction is carried out at a low pressure, just above atmospheric (0.5 to 5 bar), and high temperatures (130 to 210° C.). The hydrogen gas is thoroughly mixed into the oil, as this step restricts the reaction rate (Grau et al., 1988).
If the pressure of hydrogen gas is increased from 3 to 50 bar when soya oil is partially hydrogenated (iodine number at the start=135, at the end=70), the content of trans is reduced from 40 to 15%. The position isomerization is also reduced to a corresponding level (Hsu et al., 1989). These results are of no commercial interest, as these conditions enforce a replacement of the low pressure autoclaves by high pressure autoclaves.
According to the "half hydrogenation" theory, the concentration of activated H-atoms on the catalyst surface determines the number of double bonds being hydrogenated and deactivated without being hydrogenated respectively. A lack of activated H-atoms causes a trans- and position-isomerization (Allen 1956, Allen 1986). A lack of activated
H-atoms can be the consequence of low solubility of H 2 in the oil, or of a bad catalyst (poisoned or inadequately produced). Thus, the "half hydrogenation" theory corresponds very well to the empirical results (Allen 1956; Allen 1986; Hsu et al., 1989).
It is possible to deodorize and hydrogenate an oil in the presence of CO 2 and hydrogen (Zosel 1976). Zosel describes in detail how to use CO 2 in order to deodorize the oil. However, it must be emphasized that Zosel does not give any hint, that CO 2 should have an influence on the hydrogenation process. Furthermore, Zosel does not touch on the cis/trans problem.
In the experiments of Zosel, the catalyst is surrounded by a liquid phase during the entire process. Zosel does not disclose the composition, but in the light of the other data, we estimate that the liquid phase consists of oil (about 95%), CO 2 (about 5%) and hydrogen (about 0.03%). This phase is far away from a supercritical condition. As a consequence, the velocity of reaction is limited by the concentration of hydrogen on the catalyst surface. The same applies to all traditional hydrogenation reactions where the catalyst is in the liquid phase as well. The velocity of hydrogenation in the experiments of Zosel is about 100 kg/m 3 h, i.e. somewhat lower than in traditional hydrogenizing reactors.
FATTY ALCOHOLS.
Fatty alcohols and their derivatives are used in shampoo, detergent compositions and cosmetic preparations etc. The annual production is about 1 million tons. About 60% is based on petrochemicals, and about 40% is derived from natural fats and oils. The raw material for short chain fatty alcohols, C 12 -C 14 , is coco-nut oil and palm kern oil, whereas C 16 -C 18 comes from tallow, palm oil or palm stearin (Kreutzer 1984, Ong et al., 1989).
It is theoretically possible to hydrogenate triglycerides, fatty acids and methylesters to fatty alcohols. A direct hydrogenation of triglycerides has not been developed commercially, because the glycerol will be hydrogenated as well and thus lost. A direct hydrogenation of fatty acids requires corrosion resistant materials and a catalyst resistant to acids (Kreutzer 1984). Lurgi has developed a hydrogenation process (the slurry process), where fatty acids are introduced and are quickly esterified with a fatty alcohol to a wax ester, and then the wax ester is hydrogenated (copper chromite, 285° C., 300 bar)(Buchhold 1983, Voeste Buchhold 1984, Lurgi 1994).
Most plants for the production of natural fatty alcohols are based on methyl esters as raw material. Saturated fatty alcohols are produced at a temperature of about 210° C. and a pressure of 300 bar using copper chromite as catalyst in a fixed bed reactor. Other catalysts as copper carbonate, nickel or copper and chromic oxide will also function (Mahadevan 1978, Monick 1979, Lurgi 1994). Unsaturated fatty alcohols are produced at about 300° C. and 300 bar, normally using zinc chromite as catalyst. There are also other catalysts which selectively hydrogenate the group COOR, leaving the C═C unimpaired (Klonowski et al., 1970; Kreutzer 1984).
The reaction is limited by the solubility of hydrogen in the liquid (Hoffman Ruthhardt 1993).
Davy Process Technology markets a gas phase process where methyl esters are hydrogenated to fatty alcohols (40 bar, 200 to 250° C., catalyst without chromium) (Hiles 1994).
A lot of work has been done to develop catalysts functioning with less energy (lower temperature, lower pressure). Another object has been to develop methods for a direct hydrogenation of triglycerides to fatty alcohols without a simultaneous hydrogenation of the glycerol (Hoffman Ruthhardt 1993).
HYDROGEN PEROXIDE.
Hydrogen peroxide is used in large quantities for bleaching, cleaning, as a disinfectant and as a raw material in industrial processes etc. Earlier, hydrogen peroxide was derived by an electrolytic process. Now, oxidation of substituted hydroquinone or 2-propanol is most widely used.
There are a lot of patents concerned with direct synthesis of hydrogen peroxide from oxygen and hydrogen. The reaction medium can be acidic organic solvents or water with organic solvents using noble metals, most often palladium, as catalyst (EP-B-0049806; EP-B-0117306; U.S. Pat. No. 4,336,239; EP-B-0049809).
It is preferred that the reaction medium is free from organic constituents because of problems with purification. Several patents use acidic water as the reaction medium (pH=1-2) with addition of halides, especially bromide and chloride (<1 mM) and with noble metals or mixtures of noble metals as catalysts (EP-A-0132294; EP-A-0274830; U.S. Pat. No. 4,393,038; DE-B-2655920; DE 4127918 A1).
The velocities of reaction which are disclosed are about 1 kg/m 3 h, and the selectivity (mol hydrogen peroxide/mol hydrogen reacted) is about 75% (DE 4127918 A1).
According to theory, one can expect to obtain- high selectivity with high concentrations of oxygen and hydrogen on the catalyst surface (Olivera et al., 1994).
The object of the present invention is to obtain a very effective process for partial or complete hydrogenation of the substrates mentioned above.
According to the invention, this problem has been solved by mixing the substrate, hydrogen gas and solvent, and by bringing the whole mixture into a super-critical or near-critical state. This substantially homogeneous super-critical or near-critical solution is led over the catalyst, whereby the reaction products formed, i.e. the hydrogenated substrates, will also be a part of the substantially homogeneous supercritical or near-critical solution.
The solvent can be a saturated hydrocarbon or an unsaturated hydrocarbon which on hydrogenation gives a saturated hydrocarbon, e.g. ethane, ethene, propane, propene, butane, butene, or CO 2 , dimethyl ether, "freons", N 2 O, N 2 , NH 3 , or mixtures thereof.
Propane is a suitable solvent for many lipids. CO 2 is a suitable solvent for hydrogen peroxide and water.
The catalyst will be selected according to the reaction which is to be carried out. For a partial or complete hydrogenation of only C═C bonds, preferably a noble metal or nickel will be selected. For a selective hydrogenation of COOR to C-- OH and HO--R, the catalyst would preferably be a zinc salt, e.g. zinc chromite. For a simultaneous hydrogenation of COOR to C--OH and HO--R and a hydrogenation of C═C, the preferred catalyst would be copper chromite, another salt of copper or copper free from chrome. For a partial hydrogenation of oxygen to hydrogen peroxide, the preferred catalyst would be a noble metal.
According to the invention, the concentration of hydrogen on the catalyst surface can be controlled to very high levels. The proportion of trans fatty acids in partially hydrogenated fatty products will be much lower according to the invention than by using conventional processes, where the product has been hydrogenated to the same level using the same catalyst. The hydrogenated products will preferably contain less than 10% trans fatty acids.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing the percentage of trans fatty acids as a function of the degree of hydrogenation according to a traditional technique and according to the invention.
FIG. 2 is a flow sheet for a process according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
In a great number of hydrogenation processes, hydrogen gas is mixed with a liquid substrate and a fixed catalyst, e.g. in the hydrogenation of lipids. In certain cases the substrate can be a gas and the product a liquid, e.g. hydrogenation of oxygen to hydrogen peroxide and water. In both these cases, the velocity of reaction is limited by the concentration of gas on the catalyst surface. The reason is the transport resistances of the gas: between the gas phase and the liquid phase; through the liquid phase; and between the liquid phase and the catalyst.
In accordance with the present invention a solvent is added which completely dissolves the gas as well as the liquid, resulting in a substantially homogeneous mixture of hydrogen, substrate, product and solvent. This is possible, if the whole mixture is in a super-critical or near-critical state. The defition substantially homogeneous means, that the principal part of the gas is in the continuous phase which covers the catalyst surface. One method to confirm this is to observe the velocity of reaction, which increases dramatically when the continuous phase that covers the catalyst surface is substantially homogeneous.
VELOCITY OF REACTION.
According to the invention, the following transport resistances of the gas are reduced substantially: gas phase/liquid phase; through the liquid phase; and liquid phase/catalyst. The velocity of reaction thereby increases to a very high degree; from about 10 to about 1000 times. The consequence of this is that continuous reactors will be preferred compared to the batch reactors of to-day. The selectivity is also influenced to a very high degree.
SOLVENT.
In order to bring the whole mixture (hydrogen, substrate product and solvent) to super critical or near-critical state at appropriate pressures and temperatures, the solvent must dissolve substrate and product as much as possible.
Glycerides, fatty acids and many derivatives of fatty acids are completely miscible with super-critical propane (Peter et al., 1993). Propane can be used in any proportions together with food according to EU-regulations (Sanders 1993; EC 1984). Thus, propane is a very adequate solvent in reactions with lipids.
Water dissolves to a certain extent in CO 2 (King et al., 1992). Hydrogen peroxide dissolves more easily than water in CO 2 . Thus, CO 2 is an appropriate solvent for direct synthesis of hydrogen peroxide. (For a thorough description of super-critical technology, see McHugh Krukonis 1986; Dohrn 1994).
CATALYSTS.
The catalysts which are used today in traditional processes can in principle also be used in super-critical processes. The catalyst may however be modified to optimize selectivity, velocity of reaction, length of life, filtering properties and pressure-drop.
QUALITY OF PRODUCT.
The invention enables new possibilities to control the hydrogen concentration at the catalyst. The velocity of reaction increases substantially. The selectivity can also be influenced in certain processes. By partial hydrogenation of edible oils, the content of trans fatty acids is of importance for the quality (see background of invention).
FIG. 1 illustrates in principle how the proportion of trans fatty acids changes during hydrogenation with two different catalysts, one catalyst according to a traditional technique and another according to the new super-critical technique. The new supercritical technique makes it possible to reduce the content of trans fatty acids in comparison with the traditional technique using the same catalyst and the same degree of hydrogenation. However, using different catalysts, the difference may be less.
In FIG. 1, "trad" means traditional process; "sf" means process with super critical fluid; and "cat" means catalyst.
CONDITIONS OF REACTION.
C═C in lipids.
I. Partial hydrogenation.
At partial hydrogenation, the reaction is interrupted at a certain iodine number, e.g. 60. The substrate, e.g. vegetable, animal or marine oil, and hydrogen are dissolved in a solvent, e.g. propane. The mixture is brought to a supercritical or a near-critical state. The substantially homogeneous mixture is brought into contact with a catalyst, e.g. palladium. The content of trans fatty acids in the final product is less than 10%. The optimal reaction condition may occure over a wide experimental range and this range can be described as follows:
______________________________________ in general preferably______________________________________temperature 0-250° C. 20-200° C.pressure 10-350 bar 20-200 bartime of reaction 0*-10 min 1 μsec-1 minsolvent 30-99.9 wt % 40-99 wt %______________________________________
The solvent must dissolve the substrates at the concentrations used. The solvent can be ethane, ethene, propane, propene, butane, butene, CO 2 , dimethyl ether, "freons", N 2 O, N 2 , NH 3 or mixtures of these gases. Preferred are propane, propene, butane, butene and dimethyl ether. Most preferred is propane.
______________________________________concentration of H.sub.2 0*-3 wt % 0.001-1 wt %concentr.substrate 0.1-70 wt % 1-60 wt %______________________________________
-type of substrate:
C═C in general. Glycerides are preferred (mono-, di-, triglycerides, galactolipids, phospholipids), also fatty acids or their derivatives (e.g. methyl- and ethyl-esters).
-catalysts
noble metals: Pd, Pt, Os, . . . but also Ni.
(0* means very low values, below the lowest one under "preferably").
II. Complete hydrogenation.
At complete hydrogenation, all double bonds are hydrogenated and the iodine number is therefore near zero. The substrate, e.g. vegetable, animal or marine oil, and hydrogen are dissolved in a solvent, e.g. propane. The mixture is brought to a supercritical or near-critical condition, and the substantially homogeneous mixture is brought into contact with a catalyst, e.g. palladium.
The optimal conditions of reaction are wide and can be described in a similar way as for partial hydrogenation; the temperature is, however, somewhat higher than for partial hydrogenation (T is probably higher than T crit ).
FATTY ALCOHOLS.
The substrate, e.g. the triglyceride, the fatty acid or its derivative, and hydrogen are mixed together with a solvent, e.g. propane. The mixture is brought to a super-critical or a near-critical state, and the substantially homogeneous mixture is brought into contact with a catalyst. Different groups can be hydrogenated depending on the catalyst used (see below under "-catalyst").
The optimal reaction condition may occure over a wide experimental range and this range can be described as follows:
______________________________________ in general preferably______________________________________temperature 20-300° C. 40-300° C.pressure 10-350 bar 20-200 bartime of reaction 0*-10 min 1 μsec-1 minsolvent 30-99.9 wt % 40-99 wt %______________________________________
The solvent must dissolve the substrates at the concentrations used. The solvent can be ethane, ethene, propane, propene, butane, butene, CO 2 , dimethyl ether, "freons", N 2 O, N 2 , NH 3 or mixtures of these gases. Preferred are propane, propene, butane, butene, and dimethyl ether. Sometimes, it can be advantageous to use an entrainer. Most preferred is pure propane.
______________________________________concentration H.sub.2 0*-3 wt % 0.001-1 wt %concentr.substr. 0.1-70 wt % 1-60 wt %______________________________________
-type of substrate:
COOR in general. Preferred are fatty acids and their derivatives (e.g. methyl-ethyl- or wax esters), and also mono- di-, and tri-glycerides, but also galactolipids and phospholipids.
-catalyst:
a) selective hydrogenation of COOR, but not C═C or C--OH, e.g. zinc chromite or any other salt of zinc.
b ) hydrogenation of both COOR and C═C, but not C--OH, e.g. copper chromite, copper free from chrome or any other salt of copper.
(0* means very low values, less than the lowest one under "preferably").
An example of suitable values at optimal conditions is:
substrate 10 wt %, propane about 90 wt %, hydrogen 0.2 wt %; the mixture is brought into contact with a bed of catalyst at 250° C. and 150 bar, and has an average contact time of 30 sec.
HYDROGEN PEROXIDE.
Oxygen and hydrogen are mixed in a solvent, e.g. CO 2 . The mixture is brought to a super-critical or near-critical state, and the substantially homogeneous mixture is brought in contact with a catalyst. The solvent dissolves the reaction products, hydrogen peroxide and water. Thus, a substantially homogeneous mixture is maintained in the reactor.
The optimal reaction condition may occure over a wide experimental range and this range can be described as follows:
______________________________________ in general preferably______________________________________temperature 10-200° C. 20-10 0° C.pressure 10-350 bar 30-300 bartime of reaction 0*-10 min 1 μsec-1 minsolvent 10-99.9 wt % 60-99 wt %______________________________________
The solvent must dissolve water and hydrogen peroxide at the concentrations used. The solvent can be CO 2 , N 2 , NH 3 , or mixtures of these gases. It may also be advantageous to use an entrainer. Pure CO 2 is probably the most suitable solvent.
______________________________________concentration H.sub.2 0*-10 wt % 0.1-3 wt %concentration O.sub.2 0.1-80 wt % 1-30 wt %______________________________________
-catalyst:
noble metals, e.g. Pd or mixtures of noble metals, e.g. Pd+Au
-reaction aids:
halides, e.g. bromides or chlorides; these can be added in the preparation of the catalyst
(0* means very low values, less than the lowest under Y preferably")
The risk of explosion during some of the processing steps must be warned against.
Suitable proportions of the added constituents can be exemplified by: oxygen 3 wt %, hydrogen 0.1 wt % and CO 2 96.9 wt %. The mixture is brought into contact with a catalyst of palladium at 35° C. and 200 bar; the average contact time is 0.1 sec.
EQUIPMENT AND ANALYTICAL METHODS
Equipment
A flow sheet for the continuous reactor used, is illustrated in FIG. 2. In this figure "M" is a mixer, "Temp." a temperature controller, "A" a sampling device for analyses, "P" a pressure reduction valve, "Sep" a vessel for separation of gas/liquids and "F" a gas flow-meter. At room temperature a condensed gas, a non-condensable gas and a liquid were mixed according to the principles used by Pickel in a "Supercritical Fluid Chromatography" application (Pickel 1991). Pickel mixed CO2 nitrogen and a liquid entrainer. We mixed propane (l), hydrogen (g) and lipids (see M in FIG. 2). The same equipment can be used for the hydrogen peroxide experiments but in this case one add: CO 2 (l); oxygen+hydrogen (g); reaction aids (l).
The mixture was heated to the desired reaction temperature and was brought into an HPLC tube filled with a catalyst powder (see Temp and Reactor in FIG. 2).
After the reactor samples were collected from the high pressure section using an HPLC valve (see A in FIG. 2 and Harrod et al 1994).
The pressure was reduced to atmospheric pressure and lipids and gases were separated (see P and Sep in FIG. 2). Then the gas flow was measured (see F in FIG. 2) The gasflow was controlled by the pressure-reduction valve (P in FIG. 2).
Analysis
The product quality was analysed using silver-ion-HPLC and gradient elution (Elfman Harrod 1995). This method is developed from an isocratic method (Adolf 1994). The kind (cis/trans) and the amount of the fatty acid methyl esters (FAME) was determine. From these data the iodine value (IV) was calculated.
The density was calculated from the Peng-Robinsson equation of state (Dohrn 1994).
EXAMPLES
Example 1
Partial hydrogenation of methylesters from rapeseed oil using a palladium catalyst.
Composition and amound of the inlet flow to the reactor:
______________________________________ mole % weight % mg/min______________________________________propane 99.92 99.7 3700hydrogen 0.04 0.002 0.07FAME 0.04 0.26 10______________________________________
Reaction conditions:
______________________________________catalyst 5% Pd on char coal (E 101 O/D 5% Degussa AG)reactor volume 0.007 mlreaction time 40 mstemperature 50° C.pressure 120 bar______________________________________
productivity and product quality:
______________________________________productivity 80 000 kg FAME/m.sup.3 hIodine-value reactor inlet = 110 reactor outlet = 50FAME with trans 10% of all FAME______________________________________
Comments
This example shows that a very high productivity (80 000 kg FAME/m 3 h) and a low content of trans-fatty acids (10%) can be attained at near-critical conditions. The results above is only an example. We do not claim that it is the optimal conditions for the process.
Others (Berben et al 1995) has minimized the trans-fatty acid content using the conventional technique. The productivity became much lower (700 kg triglycerides /m 3 h) and the content of the trans-fatty acids became much higher (34%).
Example 2
Complete hydrogenation of methylesters from rapseed oil using a Palladium catalyst.
Composition and amount of the inlet flow to the reactor:
______________________________________ mole % weight % mg/min______________________________________propane 96.27 95.7 1840hydrogen 3.1 0.14 2.7FAME 0.63 4.16 80______________________________________
Reaction conditions:
______________________________________catalyst 5% Pd on char coal (E101 O/D 5 Degussa AG)reactor volume 0.007 mlreaction time 80 mstemperature 90° C.pressure 70 bar______________________________________
productivity and product quality:
______________________________________productivity 700 000 kg FAME/m.sup.3 hIodine-value reactor inlet = 110 reactor outlet <1FAME with trans <0.1% of all FAME______________________________________
Comments
This example shows that a tremendous productivity (700 000 kg FAME/m 3 h) can be attained at near-critical conditions. The results above is only an example. We do not claim that it is the optimal conditions for the process.
Example 3
Complete hydrogenation of methylesters from rapeseed oil using a nickel catalyst.
Composition and amount of the inlet flow to the reactor:
______________________________________ mole % weight % mg/min______________________________________propane 99.49 99.13 1500hydrogen 0.38 0.017 0.25FAME 0.13 0.85 13______________________________________
Reaction conditions:
______________________________________catalyst Nickel (Ni-5256 P, Engelhard)reactor volume 0.009 mlreaction time 65 mstemperature 190° C.pressure 155 bar______________________________________
productivity and product quality:
______________________________________productivity 90 000 kg FAME/m.sup.3 hIodine-value reactor inlet = 110 reactor outlet <1FAME with trans <0.1% of all FAME______________________________________
Comments
This example shows that a very high productivity (90 000 kg FAME/m 3 h) can be attained using a nickel catalyst at super-critical conditions. The results above is only an example. We do not claim that it is the optimal conditions for the process.
Example 4
Complete hydrogenation of triglycerides using a palladium catalyst.
Composition and amount of the inlet flow to the reactor:
______________________________________ mole % weight % mg/min______________________________________propane 98.7 93.6 3600hydrogen 1 0.043 1.6triglycerides 0.3 6.3 240______________________________________
The triglycerides (tg) were in this case a commercial vegetable oil.
Reaction conditions:
______________________________________catalyst 5% Pd on char coal (E 101 O/D 5% Degussa AGreactor volume 2.5 mlreactor time 12 sectemperature 50° C.pressure 100 bar______________________________________
productivity and product quality:
______________________________________productivity 5 000 kg tg/m.sup.3 hIodine-value reactor inlet = 140 reactor outlet = 0.1FA with trans <0.1% of all FA______________________________________
Comments:
This example shows that a high productivity (5000 kg triglycerides/m 3 h) can be attained at near-critical conditions. The results above is only an example. We do not claim that it is the optimal conditions for the process.
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A typical traditional reactor for hydrogenation consists of a tank filled with a liquid and a gas and a small particle catalyst. The reaction is carried out at high pressures and high temperatures. Lack of gas on the catalyst surface limits the velocity of reaction. Much work has been done to increase the quantity of gas on the catalyst. It has not been possible to solve this problem effectively with the techniques of today. According to the invention an extra solvent is added to the reaction mixture. By bringing the whole mixture (solvent, substrate, hydrogen and reaction products) to super-critical or near-critical state, a substantially homogeneous mixture can be obtained. By this method it is possible to control the concentration of gas on the catalyst to the desired level. The velocity of reaction is thereby increased considerably. The hydrogenation reactions principally involved comprise hydrogenation of carbon-carbon double bonds (C═C) in lipids; hydrogenation of COOR to C--OH and HO--R to produce fatty alcohols; and direct hydrogenation of oxygen to hydrogen peroxide.
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BACKGROUND OF THE INVENTION
This invention pertains to differential torque limiting devices for mechanical power transmission, and more particularly, to such devices having a single input with two outputs driving two independent actuators which in turn drive a single control surface or device which will tolerate only limited assymmetric loads.
Typically, a single moveable auxiliary airfoil, e.g. a horizontal stabilizer may be actuated by a single actuator although it may employ a torque tube and multiple linkages. However, a single actuator restricts provisions for suitable redundancy in the system in the event of failure of the actuator, its structural support, or its connection to the control surface. Particularly acute is a horizontal stabilizer drive system wherein the entire stabilizer is rotated to provide trim. In the event of an actuator load path failure, the entire stabilizer would be free to rotate about its hinge line and the elevators could not adequately compensate. Dual actuators, either of which will support the stabilizer, but not necessarily drive it alone, provide adequate redundancy. Acme jackscrews, which are inherently no-back devices, meet these requirements. However, employment of dual actuators necessitates synchonization of the actuators. Also the airfoil section rotated must be structurally capable of withstanding a failed or jammed single actuator where one actuator may experience the entire force associated with stall torque of the drive means. Alternately, provisions must be made to avoid this load condition.
Driving the two actuators through a conventional differential gear arrangement wherein the alternate drive outputs are the two driven bevel gears is an alternative well known in the art. In this mode, both output gears are driven only if they are loaded essentially equally. If unequally loaded, the differential pinion will walk about the more heavily loaded first driven bevel gear driving the remaining second driven bevel gear at twice normal speed. The output torque of the two driven bevel gears will be essentially equal. However, since the two actuators must stay in sync with each other, the more lightly loaded advancing screw will jam and become the heavier loaded at which time the second driven gear becomes fixed and the first driven gear rotates. This alternate cycling may continue until both outputs are essentially jammed, at which time the output torque is equally divided. Stall input torque essentially, would be shared equally between the two actuators. Alternately, if the load is lost on one driven bevel gear the differential pinion gear will rotate about the face of the second driven bevel gear (which is still loaded), simply driving the free driven bevel at twice normal speed and applying only the torque to overcome friction.
The obvious problem with this alternative is that the actuator screws may not be maintained in synchronization.
An enhanced embodiment, not hereby conceded to be prior art, is to fasten the differential pinion gear located between the two driven bevel gears to its shaft by a shear pin. This provides a dual (parallel) output mechanical drive with an asymmetrical output load limited to the shear force of the pin holding the pin gear. Once the pinion shears the apparatus is the conventional differential gear drive discussed above.
One undesirable feature with a single shear pin device is that the shear pin must be of adequate size to prevent shearing under maximum load conditions. Consequently at usual (low) operating loads the drive is not sensitive to common faults of a jackscrew actuator--e.g. lack of lubrication or dirt causing high friction and reduced output capability. High load capability from both actuators is required for dive recovery. Since dive recovery is rarely required, it is desirable to have a positive indication of high load capability during usual (low) load operation. Differential load between the two actuator drives at low loads is a good indication of actuator drive capability. The present invention provides a positive indication of actuator capability under usual operation by combining a shear pin and a brake. The shear pin will shear when the actuators have unmatched capability (high differential loading) such as when one actuator is not lubricated or dirty. Opportunity for visual observation of the shear pin is provided for the maintenance crew. With the pin sheared, trimming operation may be continued since the brake provides the differential lock for usual loading conditions.
BRIEF SUMMARY OF THE INVENTION
The present invention is a differential torque limiting device for mechanical power transmission having a single input and dual outputs, particularly adaptable to aircraft control surface actuation. While the invention pertains to any epicyclic gear train of the differential motion type, it will be described with a specific gear type and arrangement for the sake of simplicity and clarity. The input torque is applied to a drive shaft which supports a pair of facing bevel gears free to rotate with respect to the drive shaft. The drive shaft supports a pinion gear on a pinion axle which is attached to, and oriented 90° to the drive shaft axis. The pinion gear is positioned between, engaging, and driving the two bevel gears in a conventional differential gear arrangement. The pinion gear is restrained from rotating on its shaft by a shear pin in combination with a load proportional, self actuating brake between the pinion gear and its axle. The combination governs the allowable differential torque the two drive bevel gears can experience. Hence, rotation of the drive shaft rotates the attached pinion shaft and since the pinion gear is restrained from rotating by the shear pin and brake, it in turn drives the two bevel gears without relative motion between the gears. Should a differential load be experienced between the two bevel gears of sufficient magnitude to fail the shear pin and slip the brake, the pinion will then rotate on its own shaft and will do so with respect to either bevel gear experiencing the higher resisting load. Of course, if one bevel gear has lost its load, that gear may continue to rotate along with the pinion gear in relation to the loaded or jammed bevel gear. The pinion gear, in essence, works as a balance beam, and as long as the loads on the two bevel gears remain the same, the three gears will rotate as a unit, without relative rotation. This result prevails even if the shear pin and brake were removed. However, in practice, loads are not identical. Differential loading is accommodated by the combined torque required to fail the shear pin and slip the brake. As previously noted, the specific gear type described includes only a single pinion gear. However, as common with epicyclic gear trains of the differential motion type, multiple pinion gears each having a shear pin and a load proportional, self-actuating brake between the pinion gear and its axle may be employed. In the multiple pinion application, the differential load between the two driven gears is shared equally between the multiple pinion gears and may be said to share this load in parallel.
An object of the invention is to accommodate differential loads generally as a function of load on a pair of synchronized actuators driven by a single prime mover yet prevent structural damage to the driven surface in the event of a jammed actuator or loss of the driving means to one actuator. The invention enables load sensitive, differential loads by combining a fixed fuse with a load variable fuse. The fixed fuse is designed to accomodate differentials at small loads and the combination at high loads to avoid discovery of malfunctions only at high loads where control authority could be jeopardized.
A further object of the invention is to provide driving force to the actuators after removal of the differential load, e.g. aerodynamic loads, which cannot be accomplished with a shear pin alone.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an airplane control surface actuation system, including a pair of drive motors, drive fuse, two chains shown in reference, each of which drives a jackscrew, which in turn drives a control surface, not shown;
FIG. 2 is a perspective view of the differential drive assembly with the support structures generally shown in phantom lines and partially removed, (including the support bearings) for clarity;
FIG. 3 is a section view of the variable fuse differential drive shown in perspective in FIG. 2, taken on section lines 3--3, with the upper structure support removed; and
FIG. 4 is a functional drawing showing the fused differential drive in normal load operation showing two pinion gears.
FIG. 5 is an enlarged partial view taken at 5--5 of FIG. 3, showing the indexing means provided to visually reflect the position of the shear pin holding the differential pinion.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A representative airplane horizontal stabilizer trim drive actuation system is shown in FIG. 1 without the control surfaces attached to the actuators. The prime movers are shown as hydraulic motors 10, each of which can drive the variable fuse differential drive 11, which in turn, drives the two chain drives 12 and 13 about the idlers 14, 15, and 16 to the left jackscrew 17 and the right jackscrew 18. The two jackscrews 17 and 18 attach to a hinged control surface (not shown) at 20 and 21. Typically, the jackscrew 17 and 18 are provided with a screw stop 22 and a nut stop 23 which engage in the event of a limit valve (not shown) failure to arrest the actuator. Although not shown, a pair of stops 22 and 23 is generally provided top and bottom of each actuator as required. The two jackscrews must drive the control surface sychronously and must be capable of accomodating a single failed drive chain or stalled actuator torque. Also, the system must be capable of accomodating differential loads between the two jackscrews caused by variations in airloads or actuator efficiencies which can be substantial when employing Acme thread jackscrews as shown.
Turning to the detail, FIGS. 2 and 3 show the details of the variable fuse differential drive 11. The drive shaft 24, which is driven by the hydraulic motor 10, via the splines 25, is supported by the bearings 26 and 27. Supporting structure for the bearings is shown in phantom lines. Integrally attached to the drive shaft 24 is the differential pinion shaft 28. Differential pinion gear 30 is supported by the sleeve bearing 31, which engages the differential pinion shaft 28 by mating splines at 32. The splines are indicated by the dotted lines above and below the solid line at 32. The sleeve bearing 31 is retained in place by the nut 33 which is adjusted for clearance at 35 by the shims 34. Torsion shaft 36 connects to the differential pinion shaft 28 via the spline at 37 at one distal end and is connected to the differential pinion gear 30 by the shear pin 38 at the other distal end. Torsion shaft 36 is also spline connected at 40 to the sleeve 41. The cap 42 which is splined to the inside diameter of the shaft portion 45 circumscribes the sleeve 41 to provide a shearing plane at 43 for the shear pin 38 which connects the differential pinion gear 30, the cap 42, and the sleeve 41. The shear pin 38 is suitably safety wired by the wire 44 to prevent the fractured portion of the pin 38 from entering the moving parts. The differential pinion gear 30 is provided with a shaft portion 45 which in conjunction with the torsion shaft 36 provides suitable torsional resilience between the differential pinion shaft 28 and the pinion gear 30. The need for the torsional resilience in this connection will be discussed in detail later. A seal is provided at 46 to keep the bearing surface 47 of the sleeve bearing 31 clean for engagement with the bore 48 of the differential pinion gear 30. These two engaging surfaces, 47 and 48 combine to form a brake which will be discussed in detail infra.
The teeth of the differential pinion gear 30 engage the teeth of the opposing pair of driven bevel gears 50 and 51. Each of the bevel gears, 50 and 51, has an integral chain drive sprocket 52 and is supported by a pair of bearings 53 and 54, separated by a spacer 55. Adjustable shims 56 are provided to accomodate alignment of the two driven bevel gears with the differential pinion gear 30.
The first chain 12 driving the left jackscrew and the second chain 13 driving the right jackscrew are both shown in phantom lines in FIG. 2.
The main support bearings 26 and 27 are retained on the drive shaft 24 by a nut and washer 57 and 58 on either end. These bearings are supported in the aircraft structure shown in phantom in FIG. 2.
In normal operation, the input torque is applied to the drive shaft 24 at the spline 25 by the hydraulic motor 10 and the shaft 24 rotates in its bearings 26 and 27. As a result, the differential pinion shaft 28 carrying the differential pinion gear 30 drives in a circular path about the same axis.
Since the differential pinion gear 30 is pinned to the torsion shaft 36, which in turn is splined to the differential pinion shaft 28, the two bevel gears 50 and 51 must rotate in unison with the differential pinion gear 30 without relative motion between the gears. As can be best seen in the schematic of FIG. 4, the differential pinion gear 30 is working as a balance beam between the two bevel gears 50 and 51. If the loads on the two driven bevel gears 50 and 51 are equal, there is no force tending to rotate the differential pinion gear 30. As the differential load between the two sprockets 52 increases, the force tending to rotate the differential pinion gear 30 increases. Rotation of the differential pinion gear 30 is not only resisted by the shear pin 38, but the sleeve bearing 31 acts as a brake against the bore 48 inside the differential pinion gear 30. The actuator loads are transmitted to the two sprockets 52 which in turn are carried by the driven bevel gears 50 and 51 to the differential pinion 30 and these two forces can be considered to act in summation at the center line of the sleeve bearing 31 represented by the point 60. This force times the coefficient of friction between the sleeve bearing 31 and its mating surface 48 represents a force resisting rotation of the pinion gear 30. Since the normal load acting at 60 is a function of the load on the sprockets 52, the force which resists rotation of the differential pinion gear is a function of the load on the sprockets or the actuators driven thereby. It should now be readily apparent that the brake acts like a variable size pin, i.e. the resisting force is proportional to the load. The critical parameters in sizing the brake are the radius from the centerline of the drive shaft 24 to the centerline of the sleeve bearing 31 represented by the point 60 and the radius of the sleeve bearing 31 along with the coefficient of friction of the sliding surfaces. In the shown embodiment, the brake is sized so that the resisting force is 10 percent of the transmitted load. The sleeve bearing 31 is made of hardened steel and the pinion 30 of soft steel. Sufficient torsional resilience is provided in the torsion shaft 36 and the shaft portion of 45 of the differential pinion gear 30 to insure that the braking force and the sheer force of the fixed pin 38 essentially act in series for a transient differential torque. Thus the brake acts as a damper and prevents inadvertent shearing of pin 38 for torque of a temporary nature. For steady differential torques the brake and pin 38 act in parallel once steady load conditions exist.
In the embodiment shown the fixed pin 38 is sized to shear at 4% of maximum load and the brake at 10%. The combination, of course, can be varied to select the resisting loads required to meet specific requirements.
The invention offers not only the obvious advantage of combining a fixed force with a variable force to resist rotation of the differential pinion gear, but it provides drive force after the fixed pin 38 has failed. This may be a real advantage if the loads causing the failure are for some reason removed. The driven structure (in this case the horizontal stabilizer) must be designed to withstand a worse case division of load forces equal to one half the maximum driving force, plus the braking force, plus the fixed pin shear force acting on one actuator with the balance on the other actuator. In the instant case this represents 50% plus 10% for the variable brake, plus 4% for the fixed pin. This compares with 100% load to one side for a fully dual (parallel-non-differential) drive. A considerable weight saving is effected in the instant case by the reduced loading on the driven horizontal stabilizer surface.
Since the actuator will drive, after the fixed pin fails, a visual indicator is provided to show that the pin 38 has sheared as shown in FIG. 5. An index line 62 is provided on the distal end of the torsion shaft 36 which aligns with a pair of index lines 63 provided on the cap 42 with the shear pin 38 in place. An aperture 64 is provided in the cap 42 so that the index line 62 is visible. Obviously when the index lines are not aligned, the shear pin 38 has failed.
An alternative embodiment of the brake described above utilizes the thrust force component inherent in the bevel gear in conjunction with a multiple disc brake. Another alternative embodiment, is to replace the shear pin 38 with a spring loaded detent.
While the preferred embodiment shown and described above is a bevel gear type, any epicyclic gear train of the differential motion type is a suitable alternative embodiment. An epicyclic train of gears may be considered to be a train in which part of the gear axes are moving relative to some one of the axes which is the reference or fixed axis. In the described embodiment, the shaft 24 and the pinion shaft 28 correspond with the arm of the epicyclic spur-gear trains. Further, a differential motion may be considered to be a motion which is the resultant of, or difference between, two original motions.
Also, the embodiment described is of the single pinion gear type. As is very common with epicyclic gear trains of the differential motion type, multiple pinion gears may be employed with each pinion gear having its own shear pin and load proportional self actuating brake. In the multiple pinion gear configuration, the differential load between the driven gears is shared between the multiple pinion gears and the load is considered to be distributed in parallel. Of course after one shear pin fails, the balance of the shear pins will also shear as the load must then be carried by the remaining pinions. However, the multiple pinion arrangement allows each of the load proportional, self-actuating brakes to be smaller. Further, the pinions need not be maintained on pinion axles which are integral with the main drive shaft. The pinions may be supported on an independent means e.g., those typically employed in automobile differentials which use multiple pinion gears.
This invention is not limited to the embodiments disclosed above, but all changes and modifications thereof not constituting deviations from the spirit and scope of this invention are intended to be included.
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A mechanical power transmission apparatus, of the differential gear type, for actuating an airplane control surface requiring two independent actuator inputs to a single control surface. Predetermined, proportionately variable, asymmetric loads between the two actuators are accomodated by a load sensitive brake in conjunction with a fuse link which fails in the event of single actuator or drive means failure. The fuse link is provided by employing a shear pin to attach the pinion gear in the differential to the pinion shaft. The shear pin failure strength in conjunction with the load variable brake determines the allowable differential torque between the two driven bevel gears.
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CLAIM OF PRIORITY
This application claims priority under 35 USC §119(a) to European Patent application number 04 006 007. 1, filed on Mar. 12, 2004, the entire contents of which are hereby incorporated by reference.
TECHNICAL FIELD
This disclosure relates to a coupling mechanism for coupling a mobile equipment cart to a medical equipment rack.
BACKGROUND
In many cases, patients in a hospital's intensive care unit must be connected to medical equipment or receive infusions. The equipment required to this end generally is stored on an equipment rack that is, for example, coupled to a wall-mounted or ceiling-mounted stand.
In order to ensure continued patient care while a patient is being transported inside a hospital, the patient must remain connected to the medical equipment that is used to treat the patient. Medical equipment is often supported on an equipment rack, and it can be necessary to remove the equipment from the rack to transport the equipment with the patient. The medical equipment can be, for example, an infusion unit that may be provided both in the operating theater and in intensive care units and that can be carried on a ceiling- or wall-mounted stand. The infusion unit can include pump rods, with several motor-driven infusion pumps or syringe pumps or simple gravity infusion bottles that are usually attached to the pump rods. To transport the patient with the medical equipment, an equipment rack (e.g., a rack for carrying an infusion unit) generally must be removed from a ceiling-mounted or wall-mounted stand and moved along with the hospital bed that accommodates the patient.
An infusion supply apparatus (e.g., as disclosed in German Patent document No. P 39 17 892) can include a tray with supply connections, and the tray can include, on the one hand, a connection to the stationary stand (i.e., the ceiling-mounted or wall-mounted stand) and, on the other hand, a connection to a mobile cart, both connections being detachable.
The mobile cart can include an arm on which the tray of the infusion supply apparatus can be supported. Transfer of the infusion supply apparatus from the stationary stand to the mobile cart can be achieved by moving the arm of the mobile cart underneath the tray of the infusion supply apparatus, so that said arm is arranged underneath the tray and engages the tray. Thereafter, the arm is lifted upwards slightly so that it carries the tray including the infusion supply apparatus. This principle is similar to the working method of a forklift. However, this solution is expensive in its construction and complicated in its handling.
SUMMARY
In a first general aspect, a coupling mechanism for selectively coupling an equipment rack to a stationary receptacle unit and to a mobile equipment cart, the coupling mechanism includes a suspension mount disposed on the equipment rack, a first receptacle element, and a second receptacle element. The first receptacle element is disposed on the stationary receptacle unit and configured to receive the suspension mount of the equipment rack to support the equipment rack on the stationary receptacle unit. The second receptacle element disposed on the mobile equipment cart and configured to receive the suspension mount of the equipment rack to support the equipment rack on the equipment cart. The second receptacle element is movable along a column of the equipment cart.
Implementations can include one or more of the following features. For example, the suspension mount can include a crossbar extending essentially in a horizontal direction. The second receptacle element can be movable in a vertical direction along the column of the equipment cart.
The second receptacle element can include a coupling link extending essentially in a horizontal direction, and the column can include a spacing element extending in parallel to the link, and a swivel attached to the spacing element at a swivel axis and having a bolt disposed at a distance from the swivel axis and extending essentially in a horizontal direction through the coupling link can pivot about the swivel axis. The swivel can include a handle.
The column can define a vertical slot though which the second receptacle slides. At least one of the second receptacle element and the column can include rollers for mutual guidance between the second receptacle element and the column when the second receptacle element and the column are moved vertically in relation to each other. A pneumatic spring can be attached to the column and the second receptacle element and can supports vertical movement of the second receptacle element.
The second receptacle element can include two vertically spaced receptacles adapted for receiving the suspension mount, and the second receptacle element can include a hook for receiving the suspension mount. The suspension mount can include a first front crossbar adapted for coupling to the mobile equipment cart and a first rear crossbar adapted for coupling to the stationary receptacle unit. The suspension mount can further include a second front crossbar spaced apart from the first front crossbar in a vertical direction. The suspension mount can further include a second rear crossbar spaced apart from the first rear crossbar in a vertical direction. The equipment rack can include two carrier profiles that are connected to each other via the crossbars.
The link can define a recess at an end of the link through which the bolt is located when the receptacle is in a lifted position.
In another general aspect, a hospital room medical equipment rack transfer system includes a stationary rack mount disposed within a hospital room, a mobile equipment cart sized to be wheeled into and out of the room, and an equipment rack adapted to support a variety of medical equipment coupled to a patient and including a support member. The stationary rack mount includes a first coupler adapted to receive the support member of the equipment rack to secure the equipment rack. The mobile equipment cart includes a second coupler adapted to receive the support member of the equipment rack to secure the equipment rack to the mobile equipment cart to move the equipment rack into or out of the room. The second coupler is adapted to be vertically moved with respect to the mobile equipment rack to release the equipment rack from the stationary rack mount.
Implementations can include one or more of the following features. For example, the mobile equipment cart can further include a swivel member coupled to the second coupler and adapted to swivel about a fixed swivel axis and thereby move the second coupler vertically, such that the second coupler releases the equipment rack from the stationary rack mount and secures the equipment rack to the mobile equipment cart. The swivel member can include a bolt substantially parallel to and located at a distance from the swivel axis, wherein the bolt engages a substantially horizontal slot of the second coupler, such that swivel motion of the swivel member about the swivel axis is converted into vertical motion of the second coupler.
In a further general aspect, a method of transferring a medical equipment rack from a hospital room with an attached patient, can include providing a mobile equipment cart having a coupler adapted to receive a support member of the equipment rack to secure the equipment rack to the mobile equipment cart to move the equipment rack with the patient into or out of the room, moving the mobile equipment cart into a coupling position adjacent the equipment rack while the equipment rack is secured to a stationary rack mount in the hospital room, operating a handle of the mobile equipment cart to simultaneously couple the equipment rack to the mobile equipment cart and release the equipment rack from the stationary rack mount while a patient is connected to equipment on the equipment rack, and then wheeling the mobile equipment cart and coupled equipment rack from the room with the connected patient.
In one exemplary implementation operating the handle can consist essentially of pivoting the handle about a swivel axis.
DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view of a mobile equipment cart, a ceiling-mounted stand and a hospital bed.
FIG. 2 is a view of the situation of FIG. 1 from a different perspective.
FIG. 3 is a detailed perspective view of a movable receptacle.
FIG. 4 is a detailed cross-profileal view of the movable receptacle of FIG. 3 and of a column of the mobile equipment cart.
FIG. 5 is a detailed perspective view of the movable receptacle and the column of the mobile equipment cart.
FIG. 6 is a view of the perspective representation of FIG. 5 from a different perspective.
FIG. 7 is a view of the perspective representation of FIG. 6 at a different operational position.
FIG. 8 is a view of the perspective representation of FIG. 6 at a different operational position.
FIGS. 9 a, 9 b, 9 c, 9 d, and 9 e illustrate a process of coupling an equipment rack to a mobile equipment cart.
Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
FIG. 1 shows a schematic view of a stationary receptacle unit 3 in the form of a stand head of a medical ceiling-mounted stand, a mobile equipment cart 15 , and a hospital bed 33 . On a front side 1 a of the stationary receptacle unit 3 , the unit includes stationary receptacle elements 1 that are designed as hooks. For example, a total of four hook-shaped receptacle elements 1 can be provided, every two of which are arranged next to each other as a pair and wherein two pairs of hooks can be arranged adjacent to each other and spaced apart from each other in a vertical direction. The hooks are bent slightly upwards to ensure secure hooking in.
The mobile equipment cart 15 includes a carriage 31 with a column 4 attached thereon. A docking device 32 is provided on the column to dock the mobile equipment cart to the hospital bed 33 .
As shown in FIG. 2 , the mobile equipment cart 15 includes a pump rod carrier 2 coupled to the column 4 . As shown, the pump rod carrier includes two carrier profiles 29 and 30 that are connected to each other by means of crossbars 10 and 12 . Horizontal retaining arms 7 are mounted to the outwardly pointing sides of the carrier profiles 29 and 30 which, in turn, retain pump rods 8 , as can be seen both from FIG. 1 and FIG. 2 . Syringe pumps 9 are attached to the pump rod 8 . The outwardly pointing sides of the carrier profiles 29 and 30 can be provided with power outlets 11 . The electric connection of the pump rod carrier 2 to an external power supply must then only be established via one or two connections. Moreover, batteries may be provided at the pump rod carrier 2 , thus allowing battery operation of the mobile infusion unit 15 in the event that motor syringes, etc. are temporarily disconnected from the external power supply.
As shown in FIG. 3 , the movable receptacle 5 has a C-shaped profile with a wide base 5 a and short sides 5 b, and receptacle elements 25 are provided on the side of the base 5 a facing away from the sides 5 b. These hook-shaped receptacle elements 25 are similar to the hook-shaped receptacle elements 1 (shown in FIG. 1 ) are attached to the stand head 3 . Accordingly, two pairs of receptacle elements 25 that are each arranged adjacent to each other in horizontal direction are provided on the movable receptacle 5 here as well. Moreover, rollers 23 that are supported rotatably are provided at the short sides 5 b on their sides that are facing each other. Furthermore, rollers 34 are provided at the base 5 a of the C-shaped profile of the movable receptacle 5 . These rollers 34 are mounted such that their rotary axes are aligned in parallel to the short sides.
As shown in FIG. 3 , a link element 16 extends along the central axis of the movable receptacle 5 , perpendicularly to the base 5 a of the C-shaped profile and parallel to the short sides 5 b. The link element 16 has the shape of a flap and is provided with a link 17 in the form of a horizontally extending elongated hole. On its side facing away from the base 5 a of the C-shaped profile, the link 17 includes two recesses 17 a and 17 b that are pointing up and down in the assembled state.
As shown in FIG. 4 , the rollers 23 serve to guide the movable receptacle 5 in the column 4 . The column 4 has a profile that is appropriate to that end and, in its cross-profile, includes several rectangular ribs 35 , with the rollers 23 running along said ribs 35 . Furthermore, the column 4 includes on each of its sides a rectangularly extending rib 36 in its central region. Together with a rear side of a rib 35 , said rib 36 serves to guide the rollers 34 . These interlocking profiles of the movable receptacle 5 and the column 4 permit a stable and consistent guidance of the movable receptacle 5 in its up and down movement.
As shown in FIG. 6 , a spacing element 18 that is also designed in the shape of a flap and extends in parallel to the link element 16 is attached to column 4 . A swivel element 19 that is provided with a handle 22 is pivoted to the spacing element 18 . Pivoted mounting is achieved via a swivel axis 20 . As shown in FIG. 4 , the link element 16 projects through a slot (not illustrated) in the column 4 . This slot extends in vertical direction along the central axis of the column 4 . Said slot exceeds the link element 16 in length, so that the link element 16 and, thus, the entire movable receptacle 5 can be moved in the slot. Furthermore, the swivel element 19 includes a bolt 21 that extends through the link 17 . The bolt 21 and the swivel axis 20 are spaced apart from each other at a distance d, as shown in FIG. 7 .
The swinging motion of the swivel element 19 and the lifting motion associated therewith of the movable receptacle 5 are illustrated in more detail below in FIGS. 6–8 and FIGS. 9 a – 9 e.
FIG. 6 shows the swivel element 19 in a position in which the handle 22 points upwards. In this position, the mobile equipment cart 15 is moved to be coupled to the pump rod carrier 2 attached to the stand head 3 . Therein, the receptacle elements 25 are in the bottommost position, as can be seen from a comparison with FIGS. 7 and 8 . The swivel axis 20 and the bolt 21 are arranged on top of each other in vertical direction. The bolt 21 is located in the recess 17 a to the outermost left-hand end of the link 17 (see FIG. 3 ). This position reflects the situation represented in FIG. 9 b.
If the handle 22 is rotated by 90 degrees in a counter-clockwise direction (as viewed from the edge of column 4 ), the handle 22 reaches the horizontal position, as is shown in FIG. 7 . In this position, the bolt 21 and the swivel axis 20 are located in a horizontal plane intersecting the link 17 . Thus, the bolt 21 is forced to move in the link 17 out of its outermost position to the left shown in FIG. 6 to the outermost position to the right shown in FIG. 7 . In order to allow such a movement at all, the link element 16 can be moved in a vertical direction. This is accomplished by means of the aforementioned slot in the column 4 , so that the link element 16 and, thus, the entire movable receptacle 5 can move up and down. This position reflects the situation represented in FIG. 9 c.
If the handle 22 is then turned down by another 90 degrees, the position shown in FIG. 8 is reached, in which the swivel axis 20 and the bolt 21 are now again arranged on a common vertical plane. The bolt 21 is again located at the outermost left-hand position of the link 17 , to be more precise in the recess 17 b. To permit this movement, the link element 16 is moved up even further, including the movable receptacle 5 and the receptacle elements 25 attached thereto, as shown in FIG. 8 . The receptacle elements 25 are now at a higher position than the receptacle elements 1 of the stand head 3 . This position reflects the position shown in FIG. 9 d.
As can be seen from FIGS. 9 b – 9 d, the pump rod carrier 2 is, as a result, moved out of the position where it is hooked in the receptacle elements 1 on the stand head 3 to a position where it is hooked in the receptacle elements 25 of the mobile infusion unit 15 . As shown in FIG. 9 e, the mobile equipment cart 15 can now be removed from the stand head 3 . Thus, the transfer of the pump rod carrier 2 to the mobile equipment cart 15 is accomplished by a swivel motion of the swivel element 19 on the handle 22 by 180 degrees from top to bottom, wherein the rotary movement is converted into a straight-line lifting movement via the mechanical swivel assembly described.
In the illustrated embodiment, the lifting movement is supported by the force of a pneumatic spring 24 shown in FIG. 5 . The pneumatic spring 24 is attached both to the column 4 and to the movable receptacle 5 and presses the movable receptacle 5 in an upward direction. By means of this upward movement, the rear crossbars 10 and 27 of the pump rod carrier 2 are, with the help of the receptacle elements 25 on the mobile equipment cart, lifted out of the receptacle elements 1 on the stand head 3 and the front crossbars 12 and 26 are now only supported by the receptacle elements 25 .
Any unstable equilibrium that might cause the receptacle 5 to be brought out of its lifted position, which is not desirable, is prevented by the provision of the recess 17 b in the link 17 of the link element 16 and the partial positive engagement resulting therefrom.
Moreover, it is also possible to attach further devices, such as a respirator, oxygen containers, a medical emergency kit, an isolating transformer, etc., to the mobile equipment cart.
After the devices attached to the pump rod carrier 2 have been disconnected from electrical power supply, said pump rod carrier 2 can be moved away from the stand head 3 and coupled to the hospital bed 33 . By positioning the coupling mechanism on the opposite side of the receptacles for the pump rod carrier 2 , it is not necessary to turn the mobile equipment cart about its vertical axis, so that the supply lines going to the patient do not have to be passed around the mobile equipment cart.
The transfer to the receptacle elements 1 at the stand head 3 is accomplished in reversed order.
Many advantages exist. For example, the swivel and lever mechanism ensures simple construction of the device and requires only low operator forces. The simple mechanics is not susceptible to faults, so that permanent and reliable operation can be ensured. A receptacle with vertical sliding ability, which is mounted to a column of the mobile equipment cart in a movable manner, ensures that the movable receptacle is guided in a defined manner, thus facilitating the coupling process. The provision of a receptacle element on a stationary receptacle unit (e.g., a medical ceiling-mounted stand and/or on a mobile equipment cart), with the receptacle element being adapted to receive the crossbar, ensures an easy coupling process.
Two vertically spaced-apart crossbars as suspension devices and two corresponding receptacles on the mobile equipment cart or on the stationary receptacle unit can prevent the mobile infusion unit from tilting while it is coupled or decoupled.
The swivel mechanics can convert a circular swinging motion into a vertical up-and-down movement, and the swivel element can serve as a lever that reduces the forces required for lifting the movable receptacle to facilitate handling thereof.
An unstable equilibrium can be prevented from developing, whereby in such an unstable equilibrium it would be easily possible to shift the movable receptacle inadvertently from the lifted position to the lowered position, because the recess in the link can ensure that the bolt remains in this position by a partial positive engagement and can be brought out of this position only by overcoming a resistance by means of increased expenditure of force.
The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.
OTHER IMPLEMENTATIONS
A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. Accordingly, other implementations are within the scope of the following claims.
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A coupling mechanism for selectively coupling an equipment rack to a stationary receptacle unit and to a mobile equipment cart, the coupling mechanism includes a suspension mount disposed on the equipment rack, a first receptacle element, and a second receptacle element. The first receptacle element is disposed on the stationary receptacle unit and configured to receive the suspension mount of the equipment rack to support the equipment rack on the stationary receptacle unit. The second receptacle element disposed on the mobile equipment cart and configured to receive the suspension mount of the equipment rack to support the equipment rack on the equipment cart. The second receptacle element is movable along a column of the equipment cart.
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