Abstract:
Previously eviscerated poultry carcasses with legs and backs remaining are suspended from shackles ( 25 ) by their legs and moved in sequence along a processing path. The backs are received on a surface conveyor ( 18 ) having parallel conveyor flights ( 36, 37 ), so that the rounded portions ( 31 ) of the surfaces of the backs ( 30 ) seek the space between the conveyor flights, thereby tending to center the carcasses moving along the poultry path. The backs are turned from inverted attitudes to upright attitudes while the legs remain inverted, thereby tending to rotate the thighs with respect to the backs, loosening the sockets between the thighs and backs, and the visceral cavities are placed on a rotary disk ( 28 ) formed of UHMW and having peripheral teeth with radially extending teeth surfaces which engage the backbone areas of the visceral cavities of the carcasses. The rotary disk is sufficiently wide in order to span the backbone area of the visceral cavity, to urge the carcasses through a downward arc while the legs and thighs are carried horizontally and cut away from the backs of the carcasses.

Description:
TECHNICAL FIELD 
     This invention relates to automated poultry processing, particularly to an apparatus and method for use along an automated poultry processing line, to separate the thighs of poultry carcasses from the back portions of the carcasses. 
     BACKGROUND OF THE INVENTION 
     In recent years, the processing of poultry has been automated so that most of the evisceration and cut-up steps are formed by mechanical devices. This has dramatically increased the speed and efficiency of poultry processing and has thus provided the consuming public with high quality poultry products at more reasonable prices. 
     Most of the modem poultry processing equipment is designed for use along suspended conveyor systems having a series of equally spaced depending shackles from which poultry carcasses are suspended upside down by their legs and conveyed along a processing path. Various processing machines are disposed along the processing path for operating upon the suspended carcasses progressively as they move along the path, to prepare the poultry for public sale and consumption. 
     A typical poultry processing line might include, for example, a vent cutter, a bird opener, an eviscerator, a neck breaker, a lung puller, and a crop remover. In addition, such processing lines might include machines for subdividing the poultry carcasses into their various commonly consumed pieces, such as breasts, backs, wings, legs and thighs. 
     The step of separating the poultry thigh from the back portion of the carcass is difficult to perform uniformly from bird to bird and without damaging the bone of the joint where the thigh is separated from the back portion. The muscles and tendons adjacent the joint are difficult to reach with automated cutting implements and there is a hazard that the cutting implements will chip, crack or splinter the bones as they make the cuts between the bones of the joints, leaving potentially harmful bone chips in the edible product. 
     As disclosed in U.S. Pat. 5,188,559 issued Feb. 23, 1993, automated machines are available for separating the thighs from the back portions of birds as birds are suspended upside down by their legs and moved in sequence along a processing path. While the machines have been largely successful, there are occasions when the birds are not properly aligned as they pass through the initial cutting blades for initially cutting the tissue that holds the bones of the joints together at the thigh and the back portion of the carcass. The tissue surrounding the bones of the joint of the thigh and back must be progressively cut to open the joint, and once the joint is open, it is desirable to rotate the back portion of the bird with respect to the thighs so as to twist the socket of the back portion away from the thigh bones, while cutting the tissue that connects the thighs to the back portion. It is highly desirable that more of the meat be left on the thighs than on the back portion, since the thighs are much more valuable than the back portions. Also, it is desirable to make a perfect cut about the thigh bones after the back portions have been rotated to pull the thighs from their sockets so that the appearance of the meat clinging to the thighs is not degraded during the cutting and removing procedures. 
     An important aspect of achieving the perfect cut between the thigh and the back portion is control of the position of the bird as the bird progresses through the cutting and removal procedures. 
     Accordingly, it would be desirable to provide an improved method and apparatus for more accurately guiding the poultry carcass to the cutters which cut through the tissue extending between the thighs and the back portions of the carcasses, and then to firmly grasp and pull the back portion of the carcass away from the thighs with a tumbling movement of the back portion so as to rotate the back portion with respect to the proximal end of the thigh bone, causing the back portion to progressively separate from the thighs and allowing the meat which can be pulled by the thighs from the back portion to remain with the thighs, thereby enhancing the weight and value of the thighs. It is to the provision of such a method and apparatus that the present invention is primarily directed. 
     SUMMARY OF THE INVENTION 
     The present invention involves an automated apparatus for separating the legs, including the thighs, from the backs of poultry carcasses as the carcasses are progressively conveyed in sequence suspended upside down by their legs on shackles along a suspended processing path. The carcasses will have been previously processed in prior stations along the processing path for the removal of the entrails and the breasts of the carcasses, so that the carcasses are received in a “saddle” configuration with their back portions, thighs and legs still attached to each other, with the carcasses being suspended by their legs, with their tails trailing behind the rest of their backs. 
     The apparatus includes a frame adapted to be positioned beneath the suspended conveyor system and generally along the path of movement of the poultry carcasses being processed. A cutting station mounted on the frame is adapted to receive a poultry carcass and effect a pair of incisions in the tissue of the carcasses at the location of the thigh joints of the carcasses. The cutting station includes a pair of elongated parallel fixed blades which straddle the back portions of the carcasses at positions inside each thigh as the carcasses move through the processing path, and the blades progressively sever the tissue extending about the thigh-back portion joints, through a portion of the joints, but without severing all of the tissue extending from the back portions to the thighs. This leaves the thighs and legs physically connected by tissue to the back portion. The cutters are elongated so that once the leading end portion of a cutter begins its penetration through the tendons into the joint, the trailing portion of the cutter is already aligned with the joint and can extend on into the joint for completing the initial separation of the thigh bone from the skeletal portion of the back portion of the carcass. 
     The cutting station also includes a surface conveyor which engages and supports the back portions of the carcasses as the joints of the carcasses are being cut. The surface conveyor includes a pair of parallel conveyor flights which form a longitudinal gap between them for receiving the back bones of the carcasses, thereby tending to align the backbones between the conveyor flights. The conveyor is operated with a surface velocity which is greater than the velocity of the shackles, creating a sliding, relative movement between the back portions of the carcasses and the flights of the conveyor, which allows the protruding backbones to seek alignment between the flights of the conveyor. 
     A separating station is mounted on the frame of the apparatus and is positioned to receive the poultry carcasses after they have advanced through the cutting station. The separating station functions to rotate the back portions forwardly from an inverted attitude to an upright attitude while the legs remain inverted and to pull the back portions of the carcasses downwardly away from the shackled legs and the thighs and thereby separate the bones of the thighs from the backs. The separating station includes a vertically oriented rotating separator disk that has outwardly projecting teeth positioned to engage and seize the interior of the back portions of the carcasses as they move in sequence along the processing path. As the separator disk rotates, the backs are drawn around the periphery of the disk and thus are pulled in a downward arc away from the thighs of the carcasses, while the legs and thighs remain suspended in the shackles of the suspended conveyor and continue to move horizontally. The separated backs then are deposited in a receptacle beneath the apparatus while the suspended legs and thighs continue with the shackles along the processing path for further processing. Typically, the legs and thighs will be separated from each other farther down the processing path with equipment of a type disclosed in U.S. Pat. No. 4,896,399. 
     Positioned between the cutting station and the separator disk in the separating station of the apparatus are a pair of deflector bars positioned to engage and arrest forward movement of the leading portions of carcass backs as the carcasses move in sequence along the processing path. The deflector bars, being positioned in the path of the back portion of the carcasses cause the carcasses to tumble forwardly, so that the tails of the inverted carcasses which initially trailed the carcasses tumble over to an upright attitude and extend forwardly of back portions, as the back portions become engaged by the teeth of the rotary disk. The rotary separator disk is formed of relatively soft material, such as plastic or nylon (as opposed to stainless steel), and the peripheral teeth of the disk are formed so as to avoid tearing or damaging the back portions of the carcasses as the separator disk pulls the back portions in an arc path diverging downwardly away from the path of the legs and thighs. This rotation or tumbling action causes the balls of the thigh bones to be dislodged and pulled out of the sockets of the back portion. Thus, when the back is pulled away from the legs at the separating station, only tissue and not the joint itself must be separated. Knives are positioned at the arcuate path about the separator disk to cut the connecting tissue as it is being stretched between the diverging back portions and thighs so as to cut closely adjacent the back portions and to cut meat off the back portions and to retain as much meat as possible on the thighs. The result is an exceptionally clean separation of the thighs from the backs with the oysters of the thigh joints remaining on the thighs, as desired. 
     Thus, it is an object of this invention to provide an improved method and apparatus for separating the back portions from the thighs of poultry carcasses, as the carcasses are conveyed in spaced series along a processing path. 
     It is another object of this invention to provide an improved poultry leg and thigh processor of the type described wherein the balls of poultry thighs are dislodged from the sockets of the back portion of the carcasses as the backs are being pulled away from the thighs without causing damage to the bones of the birds, and with retention of more meat on the thighs. 
     Another object of the invention is to provide an improved method and apparatus for removing the thighs and legs from the back portions of poultry carcasses, which can be utilized with existing suspended shackle-type poultry processing lines. 
     Another object of the invention is to provide a poultry leg processor wherein the legs and backs of poultry carcasses are separated cleanly, reliably and uniformly with the oysters of the thigh joints remaining on the ends of the thigh bones after separation from the back of the carcass. 
     These and other objects, features and advantages of the invention will become more apparent upon reviewing the following detailed description, taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of the leg and thigh processor, with parts broken away to illustrate the movement of the saddle portion of a poultry carcass through the processor. 
     FIG. 2 is an end elevational view thereof. 
     FIG. 3 is a top plan view thereof. 
     FIG. 4 is a side elevational view thereof, similar to FIG. 1, but showing more details of the mechanical components of the leg and thigh processor. 
     FIG. 5 is an expanded prospective illustration of the surface conveyor, the separator disk and the drive motor. 
     FIGS. 6A and 6B are schematic end views of the surface conveyor, showing the spaced parallel conveyor flights and a back portion of a bird aligned between the conveyor flights. 
     FIG. 7 is an expanded perspective illustration of the components of the system that are supported by the upper horizontal support bar. 
     FIG. 8 is a partial side elevational view of a portion of a separator disk, illustrating the position of a poultry saddle as the back portion is being separated from the thighs. 
     FIG. 9 is a schematic internal view of the saddle of a poultry carcass as the leg bones are about to be twisted out of the sockets of the back portion as the saddle is moved about the separator disk. 
    
    
     DETAILED DESCRIPTION 
     Referring now in more detail to the drawings, in which like numerals indicate like parts throughout the several views. FIG. 1 illustrates the leg and thigh processor  10  which includes a lower horizontal support  12 , an upper horizontal support  14 , and an L-shaped support plate  16 , with these elements being rigidly connected together and supporting the surface conveyor  18  at the cutting station  17  and the separator assembly  20  at the separator station  21 . As illustrated in FIG. 1, the leg processor moves the saddle portion  22  of the previously eviscerated and separated poultry carcass along a processing path as indicated by arrows  24 , first through the cutting station  17  which includes the surface conveyor  18  and the cutter assembly  26  that is positioned above the surface conveyor, which work together to cut the tendons and other tissue at the joints between the thighs and the back portion of the carcass. The partially processed saddle is then moved through the separator station  21  which includes separator assembly  20  where the back portion is tumbled or rotated forwardly and guided toward the upper arc of the separator disk  28 . The separator disk and its guide bars cause the thigh/back portion joints to separate, and the tissue still connecting the joints is cut while the back portion moves on the separator disk, thereby completely separating the back portion  30  from the legs  32  and thighs  34 . 
     As illustrated in more detail in FIGS. 4 and 5, the surface conveyor  18  includes a pair of parallel conveyor flights  36  and  37 , with the conveyor flights being mirror images of each other. Conveyor flights  36  and  37  each include chain guides  38  and  39 , and the chain guides each define chain guide recesses  40  and  41 , which receive and guide conveyor chains  42  and  43 , respectively, that move in the directions indicated by arrows  42   a  and  43   a . The chain guides  38  and  39  each include a first inclined portion  44  and  45 , and a second horizontal portion  46  and  47 , causing the conveyor chains  42  and  43  to move first upwardly along the incline of the chain guide recesses, and then horizontally. 
     Chain drive sprockets  48  and  49  are positioned beyond chain guides  38  and  39 , respectively, and engage with the chains, driving the chains about the chain guides. The chain drive sprockets  48  and  49  are rotated on a common axle  50 , with the axle being supported by the upright wall of the L-shaped support plate  16 . 
     As illustrated in FIGS. 5,  6 A and  6 B, the chain guide recesses  40  and  41  of the chain guides  38  and  39  are formed with side rails  52   a  and  52   b  and  53   a  and  53   b , and a center rail  54  and  55 , respectively. The rollers  56  are positioned adjacent and tend to engage and roll on the center rails  54  and  55 , while the chain links  58  are received in the recesses  40  and  41  adjacent the side rails. 
     As illustrated in FIG. 6A, when the conveyor chains  42  and  43  move up the first inclined portion  44 ,  45  of each of the chain guides  38 ,  39 , the chain links  58  are exposed above the chain guides  38  and  39 , and are available to support the exterior surface of the back portion  30  of the saddle  22  of the poultry carcass, with the protruding backbone or spine  31  received in the space  60  between the conveyor flights. 
     The linear movement of the conveyor chains  42  and  43  is faster than the linear movement of the poultry carcass  22  as carried by the suspended shackles  25 . The edge surfaces of the chain links  58  are relatively smooth, and the surface of the bird against which the chain links are engaged is relatively slippery, so that relative movement is created between the conveyor chains  42  and  43  and the carcasses  22 . This relative movement tends to allow the protruding backbone portion  31  of the carcass  30  to seek the space  60  between the conveyor flights. This occurs as conveyor chains  42  and  43  move up the first inclined portions  44  and  45  of the chain guides  38  and  39 . 
     When the chain guides  38  and  39  guide the conveyor chains  42  and  43  along the second horizontal portion of the processing path of the conveyor flights, the inside side rails  52   b  and  53   a  are positioned higher. With this arrangement, part of the weight of the poultry carcass becomes supported on the higher inside guide rails  52   b  and  53   a , while the conveyor chains  42  and  43  continue to lightly engage and transport the poultry carcasses  22  along the horizontal run of the surface conveyor. 
     In the meantime, while the inside guide rails  52   b  and  53   a  support the carcass, the initial incision by the cutting blades at the thigh/back portion joints are made. Therefore, the downward force exerted when making the incision is borne by the inside guide rails  52   b  and  53   a . In addition, the inside guide rails  52   b  and  53   a  help stabilize the conveyor chains  42  and  43 , tending to avoid lateral shifting of the conveyor chains during the stretches of chain movements that oppose the force applied by the cutting blades to the carcass  30 . 
     As best illustrated in FIGS. 4 and 7, cutter assembly  26  is mounted to the upper horizontal support  14  over the surface conveyor  18 , and includes a pair of parallel support bars  60  and  61  which are rigidly mounted to and are coextensive with upper horizontal support  14 . A separator bow  62  includes upper support block  64  for mounting the separator bow between the support bars  60  and  61 , and a depending thigh separator  66 . The thigh separator  66  includes a downwardly depending sloped convex surface  68  and the horizontal continuation thereof  70 . The shape and incline of the separator bow is arranged to engage the poultry carcass saddles between the thighs, so as to urge the thighs in an outwardly sloped attitude, and to hold the back portion and thighs in a proper aligned position with respect to the rest of the assembly while the first and continuing cuts are made in the tendons and other tissue extending between and about the joints of the thigh/back portion. 
     A pair of mirror image elongated cutter blade assemblies  72  and  73  are mounted to the parallel support bars  60  and  61 , and each comprises a plow plate  74 ,  75 , elongated cutter blade  76 ,  77 , and a separator bar  78 ,  79 , respectively. The elongated cutter blades  76  and  77  are adjustably mounted by means of open-ended slots  80  to openings  82  of the plow plates  74  and  75 , and the separator bars  78  and  79  are similarly attached by their openings  84  to the plow plates  74  and  75 . The angles and amount of protrusion of the elongated cutter blades can be adjusted with respect to plow plates  74  and  75  and separator bars  78  and  79  by means of the elongated slots  80 . The plow plates  74  and  75  are suspended from the upper horizontal support  14  by means of outwardly extending, slotted brackets  86  and  87 . 
     It will be noted that the plow plates are angled downwardly and inwardly toward each other, with their lower edges  88  converging toward each other and with their outer surfaces angled so as to orient the thighs of the carcasses at the same angle. In addition, the leading edges of the plow plates  74  and  75  include a vertical scraper edge  90  that tends to scrap along the inner surface of the proximal end portion of the thighs of the carcass saddle to remove any fat or loose material from the carcass. In addition, plow bars  92  and  93  extend from the upper portion of the plow plates and converge together so as to deflect the legs of the on-coming carcasses away from each other. 
     The arrangement of the separator bow  62  and the cutter assembly  26  over the surface conveyor  18  requires the carcasses  22  to be received (as shown in FIGS. 1 and 2) with the legs and thighs and  34  straddling the separator bow  62  and cutter assembly  26 , and the back portion  30  positioned in sliding relationship with respect to the elongated cutter blades  76  and  77 , and with the surface conveyor  18  urging the back portion upwardly into contact with the elongated cutter blades. 
     Separator assembly  20  includes a pair of deflector bars  94  and  96  (FIG. 4) which are positioned ahead of separator disk  28 , down the processing path from surface conveyor  18 . Disk guide bar  98  extends between surface conveyor  18  and separator disk  28 , extending about the upper and rear peripheries of the separator disk. The disk guide bar  98  is inclined upwardly at its entrance portion  100 , and then is inclined downwardly over the separator disk  28  at  99 , forming an intermediate arch  101 . As shown in FIG. 1, when the poultry carcass leaves the surface conveyor  18  and cutter assembly  26 , the forward portion of the back  30  of the carcass will engage deflector bars  94  and  96  so as to rotate in a forward direction, bringing the tail  35  over the back portion, as indicated by arrow  102  (FIG.  1 ), beneath the arched portion  101  of the disk guide bar  98 , so that the interior surface of the back portion will land on and be engaged by separator disk  28 . 
     As illustrated in FIG. 8, separator disk  28  has a plurality of equally sized perimeter teeth  104  which are equally spaced about the disk. Each tooth  104  includes a radial surface  106  and a sloped surface  108 . The radial surfaces  106  of each tooth extend approximately radially from the axis  110  about which the disk rotates. A central opening  112  is formed in the disk, and the central opening is mounted on a rotary axle  114  which is rotatably supported by the L-shaped support plate  16  (FIG.  5 ). The separator disk  28  rotates in the direction as indicated by arrow  116 , so that the radial surfaces  106  are oriented approximately at a right angle with respect to the direction of rotation of the disk. Thus, when the interior surface of the back portion  30  engages the perimeter teeth  104 , the flat radial surfaces of the teeth  104  tend to carry the back portion in the direction of rotation  116 , instead of sliding beneath the back portion as might be encountered by a sloped tooth surface. In addition, the vertebrae and other protruding portions of the interior surface of the back portion tend to protrude between and become engaged by the teeth, assuring that the back portion will be firmly moved in unison with the separator disk  28 . In the meantime, disk guide bar  98 , which comprises a bifurcated bar arrangement (FIG. 7) engages the exterior of the back portion  30  and urges the back portion into firm contact with the apexes  118  of the teeth  104 . The disk guide bar  98  and disk teeth  104  carry the back portion in a downward arc away from the path of travel of the shackle  25 , leg  32  and thigh  34  in the direction indicated by arrow  24 . The rotary movement of the back portion  30  as indicated by arrow  102 , which results from the back portion rotating over the deflector bars  94  and  96  as the back portion approaches the separator disk, and then the continued rotary motion of the back portion as it is stretched downwardly away from the thighs  34  results in pulling the thigh bone from the socket of the back portion. Pairs of cutter blades  122  and  124  are supported from upper horizontal support  114  (FIG. 7) and protrude downwardly between the bifurcated disk guide bar  98 , and are located in the path of the back portion  30  as the back portion is moved by the rotation of the separator disk  28 , so that the pairs of cutter blades  122  cut the tissue extending from the back portion to the thighs  34  adjacent the back portion, thereby allowing the maximum amount of meat to be retained by the thighs. 
     Separator disk  28  is formed from a relatively soft material as compared to stainless steel. The preferred material is nylon or UHMW. However, other relatively soft materials can be utilized as may be desired. The tooth formation is formed by cutting into the edge of the material, and once the teeth have been formed, the edges are ground off to a radius that is sufficiently dull to avoid tearing of the tissue of the birds during normal operation of the system. While separator disks made from the softer materials tend to wear more rapidly than steel disks, they are much less expensive than steel disks. 
     The separator disks are 11″ in diameter from tooth apex to tooth apex, and {fraction (5/16)}″ thick. This dimension is selected so that a rather shallow downward arc of movement is imparted by the separator disk to the back portions of the carcasses, allowing the path of the back portion to diverge gradually from the horizontal paths of the thighs, so as to prolong the stretching of the tissue as the tissue is being cut by the pairs of cutter blades  122 . In the preferred embodiment, the separator has forty teeth with the radial surfaces having a height of ⅜″. The thickness of the cutter disk is chosen so as to provide a relatively wide apex  118  of the teeth which tend to straddle the vertebrae of the back portion of the bird. Also, the relatively wide separator disk is chosen over a pair of thinner parallel disks so as to avoid entrapment of undesired matter between the pair of disks. The selection of a wider tooth also spreads the force imparted by the teeth over a larger contact area of the bird, reducing the tendency to damage the bird. 
     As illustrated in FIG. 9, the saddle portion  22  of the bird is shown as it transverses the separator disk  28  in the position illustrated in FIG.  8 . The oysters  124  and  125  are to be removed with the thighs  34  as the vertebrae  126  continues to move with the separator disk  28 . The thigh bones  31  pull from their sockets and carry the oysters  125  with them. 
     The cuts into the tissue made by the pairs of cutter blades  122  are indicated at  130 . 
     The rotary axle  114  of the separator disk  28  and the rotary axle  50  of the chain drive sprockets  48  and  49  are driven by motor  132 , through gear box  134  and drive sprockets  136  and  138 . The drive sprockets  136  and  138  drive the chains  140  and  142 , respectively, that rotate the axle sprockets  144  and  146 , respectively. 
     Although a preferred embodiment of the invention has been disclosed in detail herein, it will be obvious to those skilled in the art that variations and modifications of the disclosed embodiment can be made without departing from the spirit and scope of the invention as set forth in the following claims.