Abstract:
A conveyor belt assembly ( 10 ) for conveying an object to be portioned ( 54 ) by a fluid jet ( 52 ) is disclosed. The conveyor belt assembly ( 10 ) includes a conveyor belt formed from at least a first and a second picket ( 12 ) each having a length comprised of a sequence of geometrically shaped links ( 20 ) disposed transversely across the conveyor belt. The pickets ( 12 ) are disposed in a nested relationship to each other. The pickets ( 12 ) include upper edge portions ( 22 ) that form a conveying surface ( 42 ) for supporting and advancing the object to be portioned ( 54 ). The upper edge portions ( 22 ) are tapered in the upward direction to reduce dispersion of the fluid jet ( 52 ) during impingement of the fluid jet ( 52 ) on the conveying surface ( 42 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/307,651, filed Jul. 24, 2001, the disclosure of which is hereby expressly incorporated by reference and priority from the filing date of which is hereby claimed under 35 U.S.C. § 119. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to conveyor belts, and more particularly, to conveyor belts for conveying objects to be portioned by high-speed fluid jets. 
     BACKGROUND OF THE INVENTION 
     Manufacturing processes of most products generally include the portioning of a raw or intermediary material into a desired shape or weight. In the food industry in particular, portioning systems are routinely used to trim foodstuffs into uniform sizes—for example, for steaks to be served at restaurants, chicken fillets in frozen dinners, or in chicken burgers. Also, excess fat, bone, and other foreign or undesired materials are routinely trimmed from foodstuffs. Much of the portioning/trimming of materials, in particular food products, is now carried out with the use of high-speed portioning machines utilizing high-speed fluid jets to portion objects conveyed upon a conveyor belt assembly. 
     High-speed fluid jets impinge the product with a thin, high-velocity stream of water or other fluid. Pressurized fluid is ejected from a small orifice to create the high-speed stream or jet, as is well known in the art. When the fluid jet impinges on the target product, a thin slice of material is removed, preferably without any appreciable amount of cutting fluid being absorbed into the product. 
     The portioning machines use various scanning techniques to ascertain the size and shape of the food product as it is advanced on a conveying surface. This information is analyzed with the aid of a computer, which in turn directs a mobile high-speed fluid jet to portion the food product advanced on the conveying surface into the desired shape or weight. 
     A conveyor belt assembly used with such a portioning machine must not restrict the rapid removal of the cutting fluid from the conveying surface. One method of accomplishing this is to provide a conveyor belt assembly having a conveying surface formed from a lattice network of support members. The voids between the support members of the lattice network allow spent cutting fluid to drain from the conveying surface, or to pass through the conveying surface, and into a spent cutting-fluid receiver. 
     Although existing conveyor belt assemblies of a lattice type design are capable of conveying products for use in portioning machines utilizing fluid jets, they are not without problems. First, the conveyor belt assemblies have impediments to rapid water removal—such as valleys, horizontal surface areas, or other configurations that impede rapid cutting-fluid removal. Therefore, cutting fluid can accumulate on the conveyor surface, thereby increasing the potential that the position of the product on the conveying surface will be disrupted by floating the product or its position disrupted by direct impact of ricocheted (splashed back) cutting fluid from the fluid jet. 
     Further, these impediments to rapid cutting-fluid removal also subject the object to be portioned to increased fluid absorption, and also increase the amount of splash of the cutting fluid upon impingement of the conveyor belt assembly. Increased splash causes a corresponding increase in fluid released to the work environment, and also increases the absorption of the cutting fluid into the object to be portioned. The impact of the splash can also cause shifting of the belt and the objects to be portioned, resulting in less precise cutting or portioning than desired. Further yet, these impediments subject the conveying surface to increased rates of wear, since the fluid jet more directly impinges upon their surfaces. 
     Further, existing conveying systems lack a top surface that provides a sufficient gripping surface to hold and maintain the position of objects to be portioned. Still further yet, the impediments cause the fluid jet to be disrupted as it attempts to pass through the conveyor surface. This disruption of the fluid jet disrupts the collection of the spent cutting fluid as the fluid jet is dispersed in a wide range of directions, impeding its flow directly into the spent cutting-fluid collection means. 
     Further still, existing lattice type conveyor belts are prone to having varying distances between adjacent lattices as measured along the length of the belt. During typical portioning operations, the object to be portioned is scanned at a first location and the position of the object recorded relative to the conveyor belt. Further downstream, the object is portioned. The accuracy of the portioning operation depends on keeping track of the product position form the time it is scanned to the time it is portioned. Therefore, a belt that has inconsistencies in distances between adjacent lattices can decrease the accuracy of the portioning. 
     Thus, there exists a need for a conveyor belt assembly that is substantially resistant to wear, minimizes absorption of the fluid jet into the product to be portioned, reduces the splash of the fluid jet upon impingement with the conveying surface, minimizes the splash back of the fluid jet from the conveyor belt during portioning to reduce the movement of the object being portioned, provides a conveyor surface exhibiting increased gripping capabilities, provides minimal disruption of the fluid jet upon impact with the conveying surface, and maintains consistent distances between adjacent lattices. 
     SUMMARY OF THE INVENTION 
     In accordance with certain embodiments of the present invention, a conveyor belt assembly for conveying an object to be portioned by a fluid jet is provided. The conveyor belt assembly includes a conveyor belt formed from at least a first and a second picket each having a length comprised of a sequence of geometrically shaped links disposed transversely across the conveyor belt. The pickets include upper edge portions that form a conveying surface for supporting and advancing the object to be portioned. The upper edge portions are tapered in the upward direction to reduce dispersion of the fluid jet during impingement of the fluid jet on the conveying surface. 
     In accordance with further aspects of the invention, the pickets of the conveyor belt are disposed in a nested relationship to each other. In accordance with other aspects of the invention, the first picket is pivotally attached to the second picket by a rod inserted through at least one link of the first picket and at least one link of the second picket. In accordance with additional aspects of the invention, the rods are heat-treated or otherwise hardened to resist water erosion, thereby increasing the expected useful life of the conveyor belt. 
     In accordance with still yet other aspects of the invention, the links have a first end facing a first direction, and a second end facing an opposing direction. The first ends of the links of the first picket are shaped and dimensioned to be received within the second ends of the links of the second picket in a nested relationship. In further aspects of the invention, the pickets are comprised of a sequence of geometrically shaped links selected from a group consisting of triangular shaped links, quadrilateral shaped links, curved shaped links, saw tooth shaped links, and sinusoidal shaped links. 
     In further yet aspects of the invention, the conveyor belt assembly includes a first drive chain and a second drive chain, wherein the first drive chain is positioned along a first side of the conveyor belt and the second drive chain along a second side of the conveyor belt. The drive chains are coupled to the conveying surface and can be driven to impart motion to the conveying surface. 
     In still further yet aspects of the invention, the links have a tapering of the width of the links. In some embodiments of the invention, the tapering includes linear tapering, rounded tapering, concave tapering, convex tapering, stepped tapering, tapering on one side of the links, tapering along the entire height of the links, and tapering along a portion of the height of the links. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an perspective view of a conveyor belt assembly formed in accordance with one embodiment of the present invention showing an object conveyed on a conveying surface being portioned by a high-speed fluid jet; 
         FIG. 2  is fragmentary plan view of the conveyor belt assembly shown in  FIG. 1  with the object to be portioned and the fluid jet removed for clarity; 
         FIG. 3  is an elevation view of the conveyor belt assembly shown in  FIG. 2 , depicting an object conveyed upon the conveying surface being portioned by a high-speed fluid jet; 
         FIG. 4  is a fragmentary plan view of a first and a second picket shown in  FIG. 1 , pivotally coupled to one another and a drive chain through the use of connecting rods in accordance with one embodiment of the present invention; 
         FIG. 5  is a fragmentary plan view of several interconnected pickets of the type shown in  FIG. 1 , coupled to a drive chain, where a portion of the drive chain is shown in sectional to illustrate the means by which the pickets are attached to the drive chain; 
         FIG. 6  is a planar side view of the fragment of the conveyor belt assembly shown in  FIG. 5 ; 
         FIG. 7  is a perspective view of a portion of a picket suitably used with the conveyor belt assembly depicted in  FIG. 1 , illustrating the triangular wave pattern of the picket formed by joining a plurality of triangular shaped links, with the connecting rods removed for clarity; 
         FIG. 8  is a cross-sectional view of one of the links illustrated in  FIG. 7 , the cross-section taken substantially through SECTION  8 — 8  of the link shown in  FIG. 7 , showing a linear tapering of the top end of the link; 
         FIG. 9  is a cross-sectional view of an alternate embodiment of one of the links illustrated in FIG.  7  and suitably used with the conveyor belt assembly of  FIG. 1 , showing a rounded tapering of the top end of the link; 
         FIG. 10  is a cross-sectional view of an alternate embodiment of one of the links illustrated in FIG.  7  and suitably used with the conveyor belt assembly of  FIG. 1 , showing a concave tapering of the top end of the link; 
         FIG. 11  is a cross-sectional view of an alternate embodiment of one of the links illustrated in FIG.  7  and suitably used with the conveyor belt assembly of  FIG. 1 , showing a convex tapering of the top end of the link; 
         FIG. 12  is a cross-sectional view of an alternate embodiment of one of the links illustrated in FIGS.  7  and suitably used with the conveyor belt assembly of  FIG. 1 , showing a stepped tapering of the top end of the link; 
         FIG. 13  is a cross-sectional view of an alternate embodiment of one of the links illustrated in FIG.  7  and suitably used with the conveyor belt assembly of  FIG. 1 , showing a linear tapering of one side of the link; 
         FIG. 14  is a fragmentary plan view of an alternate embodiment of the pickets suitably used with the conveyor belt assembly of  FIG. 1 , showing the pickets formed in a square-wave pattern; 
         FIG. 15  is a fragmentary plan view of an alternate embodiment of the pickets suitably used with the conveyor belt assembly of  FIG. 1 , showing the pickets formed in a smoothly varying undulatory wave pattern; 
         FIG. 16  is a fragmentary plan view of an alternate embodiment of the means for coupling several interconnected pickets of the type shown in  FIG. 1  to a drive chain, where a portion of the drive chain is shown in sectional to illustrate the means by which the pickets are attached to the drive chain; and 
         FIG. 17  is a fragmentary plan view of an alternate embodiment of the means for coupling several interconnected pickets of the type shown in  FIG. 1  to a drive chain, where a portion of the drive chain is shown in sectional to illustrate the means by which the pickets are attached to the drive chain. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention relates to a new design for a conveyor belt assembly that is particularly suitable for supporting objects to portioned, and more particularly for supporting objects to be portioned during fluid jet cutting operations. It should be noted that for purposes of this description, terminology such as left, right, vertical, horizontal, etc., are descriptive in nature and should not be construed as limiting. 
     Referring to  FIGS. 1 and 2 , the conveyor belt assembly  10  is comprised of a conveying surface  42  formed from a plurality of pickets  12 . The pickets  12  are pivotally joined to one another and to a left and right drive chain  16  and  18  by a plurality of connecting rods  14  and  15 . 
     Referring specifically to  FIG. 2 , the connecting rods  14  and  15  are elongate shafts that extend transversely and horizontally just below the conveying surface  42 . The connecting rods  14  and  15  are inserted through the pickets  12 , pivotally joining adjacent pickets  12  to one another, and pivotally joining the pickets  12  to the drive chains  16  and  18 . The connecting rods  14  and  15  are formed from heat treated or otherwise hardened metals to resist fluid erosion during impingement of the high-speed fluid jet upon the connecting rods  14  and  15 . 
     The connecting rods  14  and  15  are of two lengths. The longer connecting rods  14  are of sufficient length to extend fully through both the left and the right drive chains  16  and  18 . The shorter connecting rods  15  are of sufficient length to span between the inboard sides of the left and right drive chains  16  and  18 , but not through the drive chains  16  and  18 . More specifically, the shorter connecting rods  15  terminate prior to reaching the drive chains  16  and  18  and are not directly coupled to the drive chains  16  and  18 . 
     Referring now to  FIGS. 2 and 4 , each picket  12  in the illustrated embodiment has a length formed from a single strand of flat wire. The flat wire is repetitively bent to form links  20 , where each link is an individual “wave” in the elongate wave-shape of the pickets  12 . The pickets  12  are coupled to the left and the right drive chains  16  and  18  so that the length of the pickets  12  is perpendicular relative to the longitudinally oriented length of the drive chains  16  and  18 . 
     The orientation of the strands of flat wire is selected so that the imaginary plane containing the strands of flat wire is parallel with the average angle of attack of the fluid jet  52 , as best seen in  FIG. 3 , so that the pickets  12  present a minimal surface area for impingement by the fluid jet. For illustrative purposes only, the strands of flat wire in the illustrated embodiment are oriented parallel with an imaginary vertical plane, however it is apparent to one skilled in the art that other angles of orientation may be selected and are within the scope of this invention. 
     Referring to  FIGS. 4 and 7 , as discussed briefly above, the pickets  12  are formed from a plurality of links  20  where each link  20  is integrally joined to a transversely adjacent link  20  to form the length of the pickets  12 . In the case of the illustrated embodiment, the flat wire is bent during manufacture to have links  20  in the form of isosceles triangles having interior angles of roughly 30, 75, and 75 degrees. The 30 degree interior angle is located at an apex  24  of the triangular shaped link  20 , and the 75 degree interior angles are located on an imaginary base  27  defined by a line dissecting the nadirs  26  of the triangular shaped links  20 . 
     The links  20 , when joined to the nadirs  26  of the transversely adjacent links  20 , create elongate pickets  12  in the form of a triangular-shaped wave having constant amplitude and frequency. Although triangular-shaped links  20  are shown, it will be readily apparent to one of skill in the art that any number of geometric shapes may be selected and are within the scope of the present invention, including for example, square-wave shaped links  20  as shown in FIG.  14  and smoothly varying undulatory links  20  as shown in FIG.  15 . And further, although adjacent links  20  were joined by integrally forming the links  20  with transversely adjacent links  20  in the illustrated embodiment, it is also readily apparent to one of skill in the art that the links  20  may be separate non-integral entities joined rigidly, flexibly, pivotally, or by other means, to adjacent links  20  by any number of methods well know in the art. 
     Referring to  FIG. 7 , the links  20  are made from flat strips of material, such as ribbon wire or flat wire, having an upper edge portion  22  that defines a top surface  44 . The top surfaces  44  of the links  20 , in aggregate, form the conveying surface. The links  20  are tapered along their upper edge portion  22  to form a relatively sharp edge at their top surface  44 . The tapering of the links  20 , among other things, aids in the minimization of the splash of the fluid jet during impingement of the fluid jet upon the top surfaces  44  of the links  20 . It also provides a sharpened surface to grip the product conveyed. Although both sides and only the upper edge portion  22  of the link  20  is tapered in a linear manner in the illustrated embodiment, it is readily apparent to one of skill in the art that any number of methods for tapering the links  20  are within the scope of this invention including, but not limited to, the following: linear tapering as shown in  FIG. 8 , rounded tapering as shown in  FIG. 9 , concave tapering as shown in  FIG. 10 , convex tapering as shown in  FIG. 11 , or stepped tapering as shown in FIG.  12 . Further, the tapering may occur along one side as shown in  FIG. 13 , or both sides as shown in  FIG. 8 , along the entire height as shown in  FIG. 13 , or only a portion of the height of the link  20  as shown in FIG.  8 . 
     Referring to  FIGS. 4 and 7 , the links  20  are formed with horizontal apertures  28  and  30  bored through the apexes  24  and the nadirs  26  of the links  20 . The apertures  28  and  30  are dimensioned and aligned to allow connecting rods  14  and  15  to be transversely and horizontally inserted through the pickets  12 . The apertures  28  and  30  may be longitudinally elongate in shape to allow the connecting rods  14  and  15  a degree of horizontal freedom relative to the links  20  during operation of the conveyor belt assembly  10 . Further, the longitudinally elongate shape of the apertures  28  and  30  allows for ease of cleaning and additional tolerance to facilitate the manufacturing and assembly of the conveyor belt. It will be appreciated that forming the pickets  12  by bending a strand of flat wire is not always a precise process due to, for example, some relaxation of a link once formed by bending. 
     Referring to  FIG. 4 , the pickets  12  extend transversely across the width of the conveyor belt assembly  10 , and are aligned so that a first picket  12 A is aligned with a second adjacent picket  12 B, such that the apexes  24  of the triangle shaped links  20  of the second picket  12 B overlap in a nested relationship in the open bases  27  of the first picket  12 A. 
     Referring principally to  FIGS. 5 and 6 , and secondarily to  FIG. 2  for reference to the left drive chain  16 , the drive chains  16  and  18  are formed from successive sets of opposing linking plates  32  having a first end and a second end. The linking plates  32  are oval shaped planar members having apertures  34  at both end portions  36  of the linking plates  32 . The end portions  36  of the successive sets of linking plates  32  are pivotally interconnected by transverse linking rods  38  inserted through the apertures  34 , to thereby form the endless elongate drive chains  16  and  18 . Well-known limiting means, such as knobs  48 , are fixed or otherwise formed on the ends of the linking rods  38  to retain the linking plates  32  between the ends of the linking rods  38 . 
     The linking rods  38  are also inserted through spool members  46 . Spool members  46  include an outer roller member  56  rotatably engaged over an inner mounting cylinder  58  that is press fit within and between the apertures  34  of each set of inner linking plates  32  as is well know in the art. The inner diameter of the mounting cylinder  58  is selected to closely accept the linking rods  38  within. The spool members  46  act as spacers, as they maintain the separation of the linking plates  32 , and also as rollers, reducing wear and friction between the drive chains  16  and  18  and a drive sprocket  60 , as best seen in  FIG. 1 , of an external drive mechanism (not shown), as will be discussed in more detail below. 
     Still referring to  FIGS. 2 ,  5  and  6 , the linking plates  32  may include intermediate apertures  40  located equidistant between the apertures  34  mentioned above. The apertures  40  are dimensioned to accept the longer connecting rods  14 . During assembly, the longer connecting rods  14  are inserted through the intermediate apertures  40  of the linking plates  32  of the left drive chain  16 , through the apertures  28  and  30  in the links  20  of the pickets  12  and into the intermediate apertures  40  of the right drive chain  18 . The shorter connecting rods  15 , located alternately between the longer connecting rods  14 , terminate prior to reaching the linking plates  32  and are therefore not coupled to the linking plates  32 . Well known limiting means, such as knobs  48 , are formed or otherwise fixed on the ends of the connecting rods  14  and  15  to maintain the connecting rods  14  and  15  axial alignment relative to the drive chains  16  and  18 . With the connecting rods  14  and  15  arranged as described, the drive chains  16  and  18  are pivotally coupled to the pickets  12  that form the conveying surface  42 . 
     By coupling the connecting rods  14  to the left and right drive chains  16  and  18 , a consistent distance is maintained between successive connecting rods  14  and thus between adjacent pickets  12  as measured along the length of the conveyor belt. Therefore, if the conveyor belt assembly  10  of the present invention is used in conjunction with a system that scans and records the position of an object to be portioned relative to the conveyor belt, a constant distance is maintained between successive pickets  12 , thereby providing for increased accuracy when the object is later portioned downstream of the scanner. 
     Every other longer connecting rod  14  utilizes washers  62  at their distal ends. The washers  62  are placed between the end knob  48  and the adjacent linking plates  32 . The washers  62  may be the same thickness as the linking plates  32 . As apparent to one skilled in the art, the washers  62  allow connecting rod  14  of a uniform length to be used, despite the varying distance between the outboard sides of the left drive chain  16  and the outboard sides of the right drive chain  18 , caused by the overlapping arrangement of successive pairs of linking plates  32 . 
     Referring to  FIG. 16 , an alternate embodiment of the present invention is depicted showing an alternate method of joining pickets  12  to the drive chain  18 . In the illustrated embodiment, the longer connecting rods  14  are inserted through apertures  34  and their associated spool members  46  in the linking plates  32  of the left drive chain  16  (see FIG.  2 ), through apertures  28  and  30  in the links  20  of the pickets  12  and through apertures  34  and their associated spool members  46  in the linking plates  32  of the right drive chain  18 . The shorter connecting rods  15 , located between the longer connecting rods  14 , terminate prior to reaching the linking plates  32  and are therefore not coupled to the linking plates  32 . Well known limiting means, such as knob fittings  48 , are fixed on the ends of the connecting rods  14  and  15  to maintain the connecting rods  14  and  15  axial alignment in relation to the drive chains  16  and  18 . 
     Referring to  FIG. 17 , an alternate embodiment of the present invention is depicted showing an alternate method of joining pickets  12  to the drive chain  18 . In the illustrated embodiment, longer connecting rods  14  are inserted through apertures  34  and  40  of the drive chains  16  (see  FIG. 2 ) and  18 . Therefore, during assembly of this embodiment, the longer connecting rods  14  are inserted through apertures  34  and their associated spool members  46  in the linking plates  32  of the left drive chain  16  (see FIG.  2 ), through apertures  28  and  30  in the links  20  of the pickets  12  and through apertures  34  and their associated spool members  46  in the linking plates  32  of the right drive chain  18 . Longer connecting rods  14  are also inserted through apertures  40  in the linking plates  32  of the left drive chain  16  (see FIG.  2 ), through apertures  28  and  30  in the links  20  of the pickets  12  and through apertures  40  in the linking plates of the right drive chain  18 . Well known limiting means, such as knobs  48 , are fixed on the ends of the longer connecting rods  14  to maintain the connecting rods  14  axial alignment in relation to the drive chains  16  (see  FIG. 2 ) and  18 . 
     In light of the above description of the components of the conveyor belt assembly  10 , the operation of the conveyor belt assembly will now be described. Referring to  FIG. 1 , an object to be portioned  54  is placed on the conveying surface  42 , which is formed by the aggregate of the top surfaces  44  of the links  20 . As is well known in the art, the drive chains  16  and  18  are driven by drive sprockets  60  of an external drive mechanism (not shown) to advance the conveying surface  42  and therefore, any object to be portioned  54  placed thereon. Idler sprockets (not shown) and/or other means well know in the art are used to support the conveying surface  42  and the object to be portioned  54  during use. A high-speed fluid jet  52  is directed vertically downward with respect to the conveyor surface  42  from a fluid jet nozzle  50  and upon the conveyed object  54 , portioning the object. 
     Referring to  FIGS. 3 and 7 , as the fluid jet  52  cuts through the object to be portioned  54 , or if the fluid jet  52  is flowing prior to or after the cutting of the object, the links  20  are directly impinged by the fluid jet  52 . The tapered upper ends  22  of the links  20  of the present invention slice through the parallel oriented fluid jet  52 , minimizing the splash of the fluid jet  52 . Reductions in the degree of fluid splash cause a corresponding reduction of fluid released into the work area and in the amount of fluid absorbed by the conveyed product  54 . 
     The tapered shape of the links  20  presents minimal horizontal surfaces, valleys or other obstructive structures that can disrupt the stream flow or increase the potential for the accumulation of spent cutting fluid. Inasmuch as the tapered surfaces of the links  20  cause minimal disruption of the fluid jet  52 , the spent fluid of the fluid jet  52  passes rapidly passed the conveyor surface  42  and into a collection system (not shown). Rapid removal of spent fluid from the conveying surface  42  reduces the potential that the object to be portioned  54  will absorb the cutting fluid or for the object to be portioned  54  to be disturbed or floated from its position on the conveying surface  42 . 
     Further, it is contemplated that a vacuum or suction means (not shown) may be disposed beneath the conveyor belt assembly  10  to hold the conveyed product  54  in position, and to receive and contain the downwardly directed fluid jet  52 . The tapering of the upper edge portions  22  causes limited disruption of the fluid jet  52 , thereby serving to substantially maintain the vertical downward path of the fluid jet  52  directly into a spent fluid collection means employed beneath the conveying surface  42 , thereby aiding the collection and containment of the spent cutting fluid. Further, the tapering reduces wear on the conveyor belt, reduces a tendency to shift the conveyor belt, and reduces the likelihood of disrupting the position of the objects on the belt. 
     While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.