Apparatus and method for detecting bone fracture in slaughtered animals, in particular fowl

Abstract: Apparatus and method for detecting the presence of a bone fracture in a specific bone of a slaughtered animal or a part thereof, particularly fowl, especially for detecting a bone fracture in the leg bone of fowl, the apparatus comprising: retention means designed to retain an animal on a retention location thereof, fracture detection means designed for detecting a possible fracture in the relevant bone of the animal, and signalling means which are linked to the fracture detection means and signal whether a bone fracture is or is not present.

Description: The invention relates to the processing of slaughtered animals or parts thereof, in particular of fowl or parts of slaughtered fowl, and in particular to the industrial processing of such animals. As is known, the processing of fowl such as poultry, in particular chicken, in large quantities is mostly automated. It makes use of processing installations comprising a conveyor arrangement which forms a conveyor track for one or more retention members which can be moved along the conveyor track and are designed to carry a bird or one or more parts of birds. Located along the conveyor track are one or more processing stations where the passing bird undergoes processing, for example plucking of the feathers of the bird, making an incision in the bird, etc. An example of a known conveyor arrangement for such a processing installation is described in WO 93/13671 , where the retention members are designed for carrying the chickens or chicken parts such as drumsticks and chicken quarters, while suspended from the tarsal joint of a leg. EP-B 0 489 984 is considered the closest prior art. This patent describes an apparatus for detecting the presence of a bone fracture in a specific bone of a slaughtered animal. The described apparatus comprises retention means retaining the animals and bone fracture detection means designed for detecting a possible fracture in the relevant bone of the animal. The bone fracture detection means comprise one or more radiation sources and one or more radiation detectors. Using image analysis techniques, it is possible to establish from the observed contour any damage. The apparatus disclosed in EP-B 0 489 984 is an apparatus according to the preamble of claim 1. In practice, the operation of these known automated processing installations is found to be disrupted more often than would be desirable as a result of the leg bone being fractured, usually at a short distance below the tarsal joint retained by the retention member. Thus the drumsticks in practice are taken to a deboning station where the meat is stripped off the drumstick suspended from its tarsal joint. For this purpose, a stripper is made to engage the drumstick near the retention member and is then moved downwards, so that the meat is stripped off. If the leg bone is broken, what will often happen is that instead of the meat being stripped off the bone, part of the drumstick will tear, near the bone fracture, off the part which comprises the tarsal joint and is retained by the retention member. This torn-off part then contains a bone, thus resulting in considerable problems both in the deboning station and in possible further processing stations, so that the installation has to be stopped more often than is desirable to clear the malfunction. Data from practical experience indicate that sometimes about 10% of the drumsticks presented to a deboning station will be subject to the above-described bone fracture. A similar problem occurs in the processing of pigs, in particular the processing of pigs' legs, where boning takes place by machine and possible fracture in the leg bone can lead to considerable problems and damage, for example jamming of the deboning installation and the pig's ham becoming unsuitable for retail. In particular, the economic damage when a pig's ham is lost is much greater than that caused by the loss of a single drumstick of a chicken. It is an object of the present invention to overcome the abovementioned problems. The invention provides an apparatus according to claim 1. This arrangement is based on the idea that if no fracture is present in the relevant bone of the animal, this bone and the meat around it will behave as a single entity and will therefore overall exhibit the same reaction as a result of the mechanical load imposed. But if a bone fracture is present, those parts of the animal or part thereof to be examined which are situated on either side of said bone fracture will react differently to the imposed mechanical load. Since the imposed mechanical load is known it is therefore feasible (possibly by experiments) to establish what reaction will occur with an intact bone and in the event of what reaction the bone is fractured. The mechanical load applied to the animal or part thereof to be inspected can take a variety of forms within the scope of the inventive thought. For example it is possible, by means of procedures involving simple construction, to apply a flexural load to the bone to be inspected, but a torsional load could also be generated. It is also possible for the bone to be inspected to be subjected to a tensile load or compressive load. In an advantageous embodiment the observing means are designed for establishing, by observing a possible change of the relative orientation of the parts of the animal which are situated on either side of the possible fracture, whether there is a fracture. These observing means can comprise a camera, for example. Obviously, the mechanical load applied should not be so large that the bone to be inspected will fracture as a result of this type bone fracture detection. It may be advantageous, however, for the mechanical load to be such that a partially fractured bone will yet fracture completely or in any case will give rise to a distinctly observable change in the orientation. In an advantageous embodiment, the signalling means are linked to memory means for storing data regarding the animals or animal parts examined, these data then optionally being used for analytical purposes. In another advantageous embodiment provision may be made for the signalling means to be linked to facilities positioned upstream of the fracture detection, which handle and/or process the animal, in particular to those facilities which may possibly cause a bone fracture. In particular, this refers to the operations of conveying the animals, where there is a risk of causing a bone fracture, particularly at those points where the animals or parts thereof are placed into a mechanized conveyor means or are transferred from the one mechanized conveyor means to another mechanized conveyor means. In a further advantageous embodiment, the signalling means are linked to one or more processing facilities for the animal or part thereof which operate downstream of the fracture detection apparatus, so that the activity performed by said processing facility can be tailored to whether a bone fracture is or is not present. Thus it is conceivable for the animal or part thereof, in the event of a bone fracture, not to be processed in a mechanized fashion and to be passed to a station where manual processing takes place. In a further variant, provision can be made for the bone fracture detection apparatus to be designed for processing a plurality of types of animals and animal parts, for example both for processing drumsticks and considerably larger chicken quarters of chickens. Preferably, means are provided for this purpose which are designed for observing what type of animal or animal part is being presented to the detection apparatus. The present invention is suitable for use in the processing of fowl and pigs, but obviously the invention can also be used in processing other slaughtered animals. Advantageous embodiments of the apparatus according to the invention are described in the subordinate claims and in the following description with reference to the drawing, where: Figure 1 shows a schematic vertical side view of a first specific embodiment of an apparatus according to the invention, Figure 2 shows a schematic perspective view of a second specific embodiment of the apparatus according to the invention, Figure 3 shows a schematic perspective view of a third specific embodiment of the apparatus according to the invention, and Figure 4 shows a schematic perspective view of a fourth specific embodiment of the apparatus according to the invention. Figure 1 shows an apparatus 1 for detecting the presence of a bone fracture in a specific bone of a slaughtered fowl, or of a part of a slaughtered fowl, in this example for detecting a bone fracture in the leg bone of a drumstick 2 of a chicken. The apparatus 1 comprises a conveyor arrangement 5 which defines a, preferably endless, conveyor track 6 for a plurality of retention means 7 for the drumsticks 2 which are incorporated in the conveyor arrangement 5, and which can be moved along the conveyor track 6. The conveyor arrangement 5 shown is known per se from the application WO 93/13671 . In particular, the known retention means 7 are designed for carrying the drumstick 2 while suspended by its tarsal joint 8. At the same time, the design of said retention means 7 is such that the leg is encircled annularly at a short distance below the tarsal joint 8. These retention means 7 are further selectively actuable to retain or release the drumstick 2. This embodiment also allows whole chickens and chicken legs to be carried using the same retention means 7, and this is obviously also possible with other fowl. Not shown are drive means for moving the retention means 7 along the conveyor track 6, said drive means for example engaging the chain between the retention means 7. Positioned at an observing location along the conveyor track 6 for the drumsticks 2 are mechanical loading means 10 designed for applying a mechanical load to the retained drumsticks 2, so that the relevant leg bone is mechanically loaded at the location of the possible bone fracture. As described earlier, the possibly present bone fracture in the leg bone is suspected, in particular, at a short distance below the tarsal joint, at 9. In this example, the mechanical loading means 10 comprise an obstacle 11 which is mounted on associated support means, here frame 12 of the apparatus, so as to be able to pivot about axis 13 and which in a detection position thereof (shown in Figure 1 ) extends into the trajectory of the drumsticks 2 moved along by the conveyor arrangement 5. A restoring spring 14 is provided to push the obstacle 11, under a preferably adjustable bias, towards its detection position. The support means 12, 13 and the restoring spring 14 allow the obstacle 11 to be forced from the detection position by a passing drumstick 2, out of the way of the drumstick 2, if no bone fracture is present in the leg bone. The drumstick 2 then behaves as a stiff entity and will remain in the position where it is held by the retention means 7, although in practice minor pivoting of the drumstick 2 relative to its original position may well occur. The obstacle 11 being pushed out of the detection position to an extent which can be effected only by an intact drumstick 2 is detected by a sensor 16, for example a proximity or contact switch. The restoring spring 14 and the support means 12, 13 of the obstacle 11 are further of such design that the obstacle 11 substantially remains in its detection position as a drumstick 2 passes over the obstacle 11, if a bone fracture is present in the leg bone. In that case, the mechanical flexural load applied by the obstacle 11 to the passing drumstick 2 will cause the orientation of the part which comes into contact with the obstacle 11 to be considerably altered relative to that section of the drumstick 2 which is retained by the retention means 7, as can be clearly seen in the left-hand side of Figure 1 . As a result of undergoing deformation, the drumstick 2 now passes the obstacle 11 without the obstacle 11 pivoting away to the extent of this being detected by a sensor 16. A passage detector 17 detects whether a drumstick 2 arrives at the obstacle 11, thus allowing, if this is the case and detection by the sensor 16 fails to occur, suitably constructed control means 18 to signal that the retention means 7 which have just passed through, are carrying a fractured drumstick 2. On the basis of this signalling it is possible for the grip by the retention means 7 on the fractured drumstick 2 to be relinquished at a release location (not shown) situated downstream of the obstacle 11 and for the fractured drumstick 2 to be separated from the retention means 7. The fractured drumsticks can then possibly be assessed manually as to whether they are suitable for retail or can, for example, be further processed by hand. Preferably, a mechanical recovery device is provided at the release location not shown, said recovery device exerting a force on the fractured drumsticks 2 to separate the drumsticks 2 with a fractured bone from the retention means 7. The fractured drumsticks 2 in particular are occasionally found to jam in the retention means, thereby requiring an expulsion force, for example exerted by an expeller which is located along the track and will pivot on command. Advantageously, the drumsticks 2 are moved along at a considerable velocity, which on the one hand is advantageous for the capacity of the apparatus and on the other hand leads to an impact load on the bone to be inspected. Although Figure 1 in the side view shows only one drumstick 2 per retention means 7, it will be evident from the description of the application mentioned earlier that these known retention means 7 can be used to convey two drumsticks 2 next to one another. It is then preferable for separately acting obstacles 11 to be positioned in the two juxtaposed trajectories of the drumsticks and moreover for a separate release location with an appertaining expeller to be positioned downstream thereof for each trajectory. The apparatus shown of simple design is therefore able to establish, with a high capacity, whether a drumstick is fractured, thus allowing considerable problems to be avoided in the further processing of the drumsticks 2. Figure 2 shows a variant of Figure 1 , where the retention means 7 are designed for carrying a drumstick 2 or other part of a fowl suspended by its tarsal joint 8, in the same manner as in Figure 1 . The retention means 7 can be moved 20 along a conveyor track 6 (not shown) and in the process pass an observing location. Located at said observing location is obstacle 11', in the trajectory of a drumstick 2 carried by the retention means 7. The obstacle 11' has a substantially horizontal pivot 22 on one side next to said track and thence extends obliquely across the trajectory of the drumsticks 2 in the direction of movement of the drumsticks 2. Located on the other side of the trajectory of the drumsticks 2, opposite the obstacle 11', are lateral guide means 25, in this case a plate, for the drumsticks 2. These lateral guide means 25 are designed to present the passing drumstick 2 in a predefined trajectory to the obstacle 11'. Preferably, said lateral guide means 25 are positioned so as to cause a drumstick or other fowl part suspended from the tarsal joint 8 to be forced obliquely outwards to some extent relative to the position of hanging vertically downwards, thus applying a slight flexural load to the leg bone. Figure 2 further shows the adjustable restoring spring 14' which pushes the obstacle 11' into its detection position. Also visible is a sensor 27 which allows a unique identification of the passing retention means 7 to be observed, so that it is possible, in control arrangement 18', for example in a computer memory, to establish whether the drumstick 2 carried by the respective retention means is or is not fractured. The operation of the arrangement according to Figure 2 is identical to that of the arrangement described earlier. If the drumstick has no bone fracture in the leg bone, in particular not at a short distance below the tarsal joint, the obstacle 11' will pivot away to the side as the drumstick 2 passes, this being detected by the sensor 16'. If the drumstick 2 does have a fracture, the obstacle 11' more or less remains in its position and deforms the drumstick 2 in such a way that the latter passes over the obstacle 11'. For chicken quarters, which do have a heavier section at the side facing away from the tarsal joint than drumsticks do, it may be advantageous for said heavy part to be supported to some extent as it passes along the obstacle 11'. Figure 3 shows another solution for the bone fracture detection. The apparatus 30 shown comprises a conveyor arrangement 31 with retention means 33, which can be moved along a conveyor track 32, for drumsticks 2 and/or other parts of fowl. The design of the retention means 33 is such that their section 34 which latches onto the drumstick 2 can swivel about a pivot 35 relative to the part 36 which is in contact with the conveyor track. Located at the observing location shown in Figure 3 , past which the retention means 33 are moving, preferably at considerable speed, are tilting means (not shown), for example a guide member, which tilt the pivotable part 34, with a drumstick 2 retained therein, into such a position that the relevant bone in which the bone fracture is suspected is loaded by the weight of the drumstick 2 itself. If the bone then is fractured, it is possible in a simple manner, for example by means of a camera system, but also by means of one or more, possibly mechanical sensors, to establish whether the tilted drumstick is still straight, as indicated by A in Figure 3 or has snapped, as indicated by B in Figure 3 . The mechanical load acting on the leg bone can of course be considerably increased if the tilting takes place at a considerable acceleration. In a variant which is not shown, the last-mentioned aspect is utilized by providing the conveyor track with a bend and allowing a centripetal force to act on the retained fowl parts as they pass the bend. In another variant, the intended mechanical load is applied by causing the fowl to pass through a liquid (stream) or a gas stream, so that the bird is thereby subjected to a mechanical load. It will also be possible to apply a torsional load to the bone to be inspected. In processing slaughtered animals, e.g. chickens, particularly automated processing, it is important to know whether a wing section of a chicken is broken. This is particularly true if the chicken is delivered to a facility for separating the wing sections from the body. For this purpose, in a not shown embodiment of the invention, bone fracture detection means are located along the conveyor track, which observe whether the shape and/or position of a wing section of a passing chicken deviates from a standard shape and/or position of an intact wing section. It can be observed that chickens have intact wing sections, while another chicken has a broken wing section. In a further not shown embodiment, the bone fracture detection means comprise not a screen but a camera which can record an entire chicken or that part of the chicken which is relevant for bone fracture detection, and which is linked to image processing means and signalling means (not shown) which compare the camera image with a predefined standard image and on the basis of that comparison establish whether a wing section is or is not broken. It will be obvious that the same camera image can also be used for other purposes. Figure 4 again reveals a partly shown retention member 7 and a slaughtered chicken 62 suspended therefrom by its legs 60, 61. As mentioned earlier, the retention member 7 permits tilting about a substantially horizontal tilting axis 63 of that part 64 of the retention member 7 which latches onto the legs 60, 61 below the tarsal joint. By imposing that tilt, the legs 60, 61 are subjected to a flexural load, allowing a difference in reaction to be observed between an intact leg, in this case leg 61, and a fractured leg, in this case leg 60. In this example a camera 67 has been installed which records the entire chicken or only the section of it near the legs. By suitable processing of the camera image and comparison with a standard image of an intact leg it is possible to establish that the leg 60 is fractured. Instead of a camera 67 it would also be possible, for example, to use a screen, or a feeler, by means of which the shape of each leg upon tilting of part 64 can be detected.

Claims: Apparatus (1) for detecting the presence of a bone fracture in a specific bone of a slaughtered animal (40, 41, 42, 62) or a part (2) thereof, particularly fowl, especially for detecting a bone fracture in the leg bone of fowl, the apparatus (1) comprising: - retention means (7, 33) designed to retain an animal (40, 41, 42, 62) or a part (2) thereof on a retention location thereof, - bone fracture detection means (10, 16, 16', 17, 47, 67) designed for detecting a possible fracture in the relevant bone of the animal, - signalling means (18, 18') which are linked to the bone fracture detection means (10, 16', 48, 50, 67) and are adapted to signal whether a bone fracture is or is not present, characterized in that the bone fracture detection means (10, 16, 16', 17, 47, 67) comprise: i. mechanical loading means (10) designed for applying a mechanical load to the retained animal or a part thereof, so that the relevant bone is mechanically loaded at the location of the possible bone fracture; ii. observing means (16, 16', 48, 50, 67) designed for observing a reaction of the animal or part thereof resulting from the mechanical load; and in that the signalling means (18, 18') are linked to the observing means (16, 16', 48, 50, 67) and - depending on the observed reaction - are adapted to signal or not to signal a bone fracture. Apparatus according to claim 1, wherein the observing means (16, 16', 42, 50, 67) are designed for observing a change or deviation resulting from the mechanical load in the orientation of a part of the animal with respect to that part of the animal onto which the retention means (7,33) latch. Apparatus according to one or more of the preceding claims wherein the observing means (10,16,16') are designed for observing a mechanical load which is applied by the animal to the observing means (10,16,16') and results from the load applied to the animal by the mechanical loading means (10), wherein the signalling means (18,18') are designed for signalling a bone fracture as a function of the possible difference between the load applied by the mechanical loading means (10) and the load observed by the observing means. Apparatus according to claim 1, wherein the mechanical loading means impose a vibration on the animal and the observing means are designed for observing a resulting vibration in a part of the animal at a distance from the retention location, and wherein the signalling means are designed for signalling a bone fracture as a function of the possible difference between the imposed vibration and the observed vibration. Apparatus according to one or more of the preceding claims, wherein the apparatus further comprises a conveyor arrangement (5,31) which defines a, preferably endless, conveyor track (6,32) for one or more retention means (7,33) which are incorporated in the conveyor arrangement (5,31), can be moved along the conveyor track (6,32) and are each designed for retaining one or more animals (40,41,42,62) or animal parts (2), the conveyor arrangement (5, 31) being further provided with drive means for moving the retention means (7,33) along the conveyor track (6,32), and wherein the bone fracture detection means (10,16,16',17,47,67) are positioned along the conveyor track (6,32) defined by the conveyor arrangement (5,31). Apparatus according to one or more of the preceding claims, wherein the bone fracture detection means are designed for processing a plurality of types of animals or parts thereof, and wherein the bone fracture detection means include means for observing the type of animal or animal part examined by the bone fracture detection means. Apparatus according to claim 6, wherein the bone fracture detection apparatus is designed for tailoring the detection to the type of animal to be examined, in particular tailoring the mechanical load applied to the type of animal to be examined. Apparatus according to claims 1 and 5, wherein the mechanical loading means are designed for applying a mechanical load to the animal or animal part moved along by the conveyor arrangement (5,31), that point of action of the animal or animal part (2) upon which the mechanical load is acting being at a distance from the retention location, and the magnitude and direction of the mechanical load being such that a passing animal or animal part (2) without a bone fracture in the relevant bone will substantially not be deformed, and a passing animal or animal part (2) having a bone fracture in the relevant bone between the retention location and the point of action exhibiting a change in the orientation of the loaded section relative to the section retained by the retention means. Apparatus according to claim 1, wherein the mechanical loading means are designed for acting on the retention means (7,33) in such a way that an acceleration or deceleration of the retention means (7,33) is effected, causing the relevant bone to be loaded by inertial forces at the location of the possible fracture. Apparatus according to claim 1, wherein the mechanical loading means are designed for allowing the animal or animal part to pass through a liquid (stream) or a gas stream, so that the animal or animal part is thereby subjected to a mechanical load. Apparatus according to claim 1, wherein the mechanical loading means comprise an obstacle (11,11') which is movably supported by associated support means (12,14) and which in a detection position thereof extends in the track of the fowl moved along by the conveyor arrangement, said support means allowing the obstacle (11,11') to be forced from the detection position by an animal or animal part (2) if no bone fracture is present, and which support means (12,14,14) substantially maintain the obstacle (11,11') in its detection position if a bone fracture is present, so that the animal or animal part can only pass the obstacle (11,11') while undergoing deformation. Apparatus according to claim 11, wherein the obstacle (11, 11') can be pivoted with respect to a corresponding fixedly mounted frame (12). Apparatus according to claim 11 or 12, wherein restoring means (14, 14') are provided which force the obstacle (11, 11') under a preferably adjustable bias towards its detection position. Apparatus according to claim 5, wherein passage detection means (17) are provided for detecting a passage of an animal or animal part (2) past the bone fracture detection means (10,16,16'). Apparatus according to claim 5, wherein the retention means (7) are selectively actuable so as to retain or release the animal or animal part (2), wherein downstream of the bone fracture detection means (10,16,16',17) along the conveyor track (6) a release location for delivering from the conveyor arrangement (5) an animal or animal part (2) having an observed bone fracture is provided, and wherein control means are also provided for selectively actuating the retention means (7), so that an animal or animal part (2) having a bone fracture is separated at the release location from the retention means (7). Apparatus according to claim 15, wherein, at the release location, a mechanical recovery means is provided which exerts a force on the animal or animal part to separate the animal or animal part (2) having a bone fracture from the retention means (7). Apparatus according to one or more of the preceding claims wherein the retention means (7) also comprise a retention member (64) which is designed for retaining a plurality of animal parts (60,61). Apparatus according to one or more of the preceding claims, wherein the retention means (7,33) are designed for carrying a bird (40-42,62) or bird part (2) while suspended from the tarsal joint (8) of one or more legs (60,61). Apparatus according to claim 18, wherein the retention means (7,33) are designed for annularly encircling each leg below the tarsal joint (8). Apparatus according to claim 5, wherein guide means (25) for the animal or animal part (2) are provided near the bone fracture detection means (16',17), said guide means (25) being designed for presenting the passing animal or animal part (2) in a predetermined trajectory to the bone fracture detection means (16',17). Apparatus according to claims 18 and 20, wherein lateral guide means are provided which lateral guide means are designed for forcing a bird suspended from the tarsal joint into a somewhat oblique position relative to the position hanging vertically downwards, thereby applying a small flexural load to the leg bone. Apparatus according to claim 1, wherein the mechanical loading means (10) are designed for substantially applying a flexural load to the relevant bone. Apparatus according to claims 5 and 22, wherein the flexural load is substantially oriented in the plane of the trajectory of the animal or animal part (2). Apparatus according to claims 5 and 22, wherein the flexural load is oriented substantially at right angles to the plane of the trajectory of the animal or animal part (2). Apparatus according to claim 1, wherein the means for applying a mechanical load are designed for substantially applying a torsional load to the relevant bone. Apparatus according to claims 1 and 5, wherein the retention means (7,33) are tiltably mounted with respect to the conveyor arrangement (5,31), and wherein the mechanical loading means comprise tilting means which tilt the retention means (7,33), together with an animal (62) or animal part (2) retained therein, into such a position that the relevant bone in which the bone fracture is suspected is loaded by the animal's or animal part's own weight, possibly increased by an acceleration generated in the tilting operation. Apparatus according to claim 1 especially for detecting a bone fracture in the leg bone of a chicken, wherein the bone fracture detection means comprise - mechanical loading means designed for applying a mechanical load to the retained bird (40-42, 62), so that the relevant bone is subjected to mechanical loading at the location of the possible bone fracture. Apparatus according to one or more of the preceding claims, wherein the bone fracture detection means detect whether a wing of a slaughtered bird is broken. Method for detecting the presence of a bone fracture in a specific bone of a slaughtered animal (40-42, 62) or a part (2) thereof, particularly fowl, wherein use is made of an apparatus according to one or more of claims 1-28, and wherein the bone fracture detection means (10, 16, 16', 17) apply a mechanical load to the animal or animal part (2) and observe a reaction of the animal or animal parts (2) which results from the mechanical load, and in that the signalling means (18,18') depending on the observed reaction - signal or do not signal a bone fracture. Method according to one or more of the preceding claims 30 or 31, wherein the animals or animal parts (2) after bone fracture detection is complete are subjected to handling and/or processing by means of one or more handling and/or processing facilities, and wherein the signalling means (18,18') are linked to one or more of said handling and/or processing facilities, so that the operation of the respective facility or facilities can be controlled.

Inventors: JANSSEN PETRUS CHRISTIANUS HEN, VAN DEN NIEUWELAAR ADRIANUS JO, VAN HAPPEN FRANCIS WILEM JOHAN, JANSSEN, PETRUS CHRISTIANUS HENDRIKUS, VAN DEN NIEUWELAAR, ADRIANUS JOSEPHES, VAN HAPPEN, FRANCIS WILEM JOHAN
Applicants: STORK PMT, STORK PMT B.V.
Application year: 1999
Main classification: A22B5
IPC codes: A22B5, A22C17, A22C21