Patent Publication Number: US-2004058636-A1

Title: Automatic cutting of products such as carcasses

Description:
[0001] This invention relates to cutting of products, such as biological products, and particularly (although not exclusively) to the splitting of animal carcasses, e.g. in abattoirs, boning plants, etc.  
       [0002] There are many fields in which cutting of products is desirably carefully controlled to account for variations in internal structures. For example, in cutting of human and animal tissues, including for medical and veterinary purposes, and for forensic purposes, the line of cutting or incision can be most important, e.g. to take account of the positions of organs, bones, muscles, tendons, nerves, arteries, etc. Such cutting to date essentially relies on the knowledge and skills of the human operator.  
       [0003] In another field of processing carcasses of slaughtered animals in abattoirs and boning plants cutting of carcasses or carcass parts is performed to create the required meat cuts such as split carcass halves as well as smaller cuts. These processes are predominantly performed manually or under manual control.  
       [0004] In the processing of slaughtered animals (including bovine and ovine animals, and pigs), the slaughtered animal, after removal of the bead and evisceration, is split along the spine into two halves. Automatic apparatus for carcass splitting has been proposed and developed in the past and various means have been developed for locating and tracking a saw along the spine. It is undesirable for the saw to deviate significantly from the centre of the spine since this can lead to damage to the meat and either loss of meat or reduction in value of the meat. For example, if the saw runs off the spine and cuts through meat at one side of the spine, the loss of and damage to the meat by the saw can be costly to the producer.  
       [0005] There have been in the past mechanical systems developed for trying to keep the carcass splitting saw accurately centred on the spine during the carcass splitting operation. For example, rigidly clamping the carcass in a known position has been proposed or attempted, but this relies on significant uniformity amongst the carcasses being processed and it has been realised that there are significant anatomical variations between individual animals. For example, a lateral deviation of the spine from the median plane of the carcass even if securely clamped against movement can cause deviation of the line of splitting from the centre of the spine.  
       [0006] Also in the past, attempts lave been made to mechanically track the line of the spine during the carcass splitting operation so that the saw will more accurately follow the line of the spine. For example, in patent specification U.S. Pat. No. 5,392,292 (Rankin, et al) there is disclosed a carcass splitting apparatus having a spine tracking or following means comprising rolling contact wheels whir are urged into engagement with the carcass on opposite sides of the spine and which, by straddling he spine, enable the adjacent cutting saw to remain substantially centred on the spine. In general concept, patent specification U.S. Pat. No. 4,667,368 (Menqi) discloses also a mechanical guiding device which follows the spine during the carcass splitting operation. These mechanical spine tracking or following devices rely on the spine being sufficiently well defined to be able to maintain the accurate-tracking function. If the spine is not well defined (e.g. depending on anatomical characteristics of the animal species or breed or of the individual animal carcass being split), such mechanical tracking systems can still result in inaccurate splitting of the carcass.  
       [0007] It is an object of the present invention in a first aspect to provide a method of automatically cutting a product having internal structures along, a path dependent on the conformation of the internal structures.  
       [0008] It is an object of the present invention in a second aspect to provide a method and apparatus for automatically cutting a human or animal body part along a path that is dependent on the internal tissue structures.  
       [0009] It is an object of the present invention in a third aspect to provide a method and apparatus for splitting the carcass of a slaughtered animal so that splitting can be accurately maintained along the centre of the spine.  
       [0010] It is a preferred object of the present invention in the third aspect to provide a method and apparatus for splitting the carcass of a slaughtered animal which can at least provide a useful alternative to mechanical systems for maintaining the accuracy of the carcass splitting operation.  
       [0011] According to the present invention in its first aspect there is provided a method from automatically cutting a product having internal structures in a manner dependent on the conformation of the internal structures, the method including the steps of supporting the product so that it is restrained against movement in at least one direction, cutting the product while supported and restrained against movement by relatively moving a cutting means so as to cut the product along a path, scanning the product ahead of the cutting location to generate data signals including data pertaining to the location and/or conformation of the internal structures of the product, processing the data signals from the scanning operation so as to generate control signals dependent on the location and/or conformation of the internal structures, and, in response to the control signals, controlling the position of the cutting means during cutting operation in at least two degrees of freedom so as to cut the product along a path dependent on conformation of the internal structures. By scanning the product to detect internal structures, it becomes possible to cut along a path to take account of those internal structures. This can be useful for a wide variety of applications such as cutting natural products such as plant matter (fruit, vegetables, timber, etc.) and animal matter (for medical/surgical or veterinary purposes or procedures, including forensic procedures) and also for cutting manufactured products, artefacts and perhaps archaeological articles.  
       [0012] When the product is not a rigid product and there is some degree of flexibility of the product or internal structures thereof, the step of restraining the product against movement preferably includes restraining the product in the general region where the cutting is taking place so that there is no substantial movement of the internal structures of the product after it has been scanned and the conformation of the internal structures determined but before the cutting means performs the cut along the path.  
       [0013] Preferably the step of scanning the product to locate the internal structures thereof occurs close to the cutting location, e.g. a few centimeters ahead of the cutting means.  
       [0014] The step of scanning the product preferably comprises generation of signals within the product whose echoes from reflections at interfaces between adjacent internal structures having differing densities are detected to generate the data signals. The step of scanning the product may be carried out using non-contact means such as microwave or radar scanning means to minimise wearing of the scanning components and extend the longevity thereof.  
       [0015] The step of scanning preferably comprises an ultrasonic scanning process in which ultrasonic pulses are generated within the product by a source that is progressively advanced along the surface of the product and in which an associated detector is provided and located to detect reflected or echo signals from interfaces between internal structures having differing densities, the detector being operative to generate the data signals.  
       [0016] The degrees of freedom preferably include at least one degree of freedom of rotational movement of the cutting means.  
       [0017] According to a second aspect of the present invention ere is provided a method for automatically cutting tissues of an animal body part which includes the steps of supporting the animal body part in such a manner that it is restrained against substantial movement in at least one direction, cutting the body part while supported by moving, a cutting means relatively along the body part, scanning the tissues of the body part ahead of the cutting location to generate data signals including data pertaining to the location and/or conformation of internal structures of the body part, processing the data signals from the scanning operation so as to generate control signals dependent on the location and/or conformation of the internal structures and, in response to the control signals controlling the position of the cutting means during the cutting operation in at least two degrees of freedom so as to cut the body part along a path dependent on the conformation of the internal structures.  
       [0018] When there is some degree of flexibility of the body part or internal structures thereof, the step of restraining, the body part against movement preferably includes restraining the body part in the general region where the cutting is talking place so that there is no substantial movement of the internal structures of the body part after it has been scanned and the conformation of the internal structures determined but before the cutting means performs the cut along the path.  
       [0019] The step of scanning the body part to locate the internal structures thereof preferably occurs close to the cutting location, e.g. a few centimeters in advance of the cutting means.  
       [0020] The step of scanning, the body part may comprise generation of signals within the body part whose echoes frown reflection at interfaces between adjacent internal tissue structures having differing densities are detected to generate the data signals.  
       [0021] In particular, the step of scanning preferably comprises an ultrasonic scanning process in which ultrasonic pulses are generated within the body part by a source that is progressively advanced along the surface of the body part and in which an associated detector is provided and located to detect reflected or echo signals from interfaces between internal tissue structures having differing densities, the detector being operative to generate the data signals.  
       [0022] As with the first aspect of the invention, the decrees of movement preferably include at least one degree of freedom of rotational movement of the cutting means.  
       [0023] The body pant may consist of a part of the carcass of a slaughtered animal and, in this case, the cutting of the part of the carcass mal separate the part into at least two carcass sub-parts with the path of the cut being dependent on conformation of bones within the carcass body part.  
       [0024] For example, the carcass part may comprise one of the two sides of a slaughtered quadruped which has been split along the spine, the cutting of the carcass part comprising cutting the carcass side into predetermined marketable cuts selected from forequarter, hindquarter, primal cuts including butt, rump and loin, short loin, strip loin, rib set, chuck and blade, chuck square cut, neck, brisket, shin and shank, ribs, and other standard carcass cuts.  
       [0025] According to a third aspect of the present invention, which is a special case of the second aspect, there is provided a method for automatically splitting the carcass of a slaughtered animal which includes the steps of supporting the carcass so that it is restrained against substantial lateral movement or other degrees of free movement, splitting the carcass while supported by relatively moving a splitting means longitudinally along the carcass, scanning the tissues of the animal carcass ahead of the splitting location to generate data signals including data pertaining to the location and/or conformation of the spine of the carcass, processing the data signals from the scanning operation so as to generate control signals dependent on the location and/or conformation of the spine, and, in response to the control signals, controlling the position of the splitting means during the splitting operation in at least two degrees of freedom so as to split the carcass along substantially the centre of the spine.  
       [0026] By scanning the carcass tissues ahead of the splitting location as the splitting operation progresses and by processing the data signals from the scanning operation preferably to locate the centre of the spine, it is possible to accurately maintain the line of splitting along the centre line of the spine.  
       [0027] The step of supporting the carcass preferably includes at least laterally restraining the carcass in the general region where the splitting operation is taking place during the process of splitting the carcass so that there is no substantial movement of the carcass spine after it has been scanned and its centreline determined but before the splitting means splits the spine. That is the scanning and splitting operations may occur close to one another in real time. Preferably the scanning means is located close to the splitting location, e.g. a few centimeters in advance of the cutting means.  
       [0028] Preferably the step of scanning of the tissues comprises generation of signals whose echoes are detected from reflections at interfaces between bone and other tissues. The step of scanning may comprise an ultrasonic scanning operation in which ultrasonic pulses are generated by a source that is progressively advanced along the surface of the carcass in the vicinity of the spine and an associated detector which detects reflected or echo pulses from interfaces between bone and other tissues and which generates the data signals.  
       [0029] Preferably the degrees of freedom include at least one degree of freedom of rotational movement of the cutting means.  
       [0030] The present invention in a fourth aspect also provides apparatus for automatically cutting tissues of an animal body part, the apparatus including:  
       [0031] support means for supporting the animal body part so that it is restrained against substantial movement in at least one direction,  
       [0032] cutting means operative to cut the body part while supported by the support means, the cutting means including moving means for moving the cutting means relatively along the body pant to trace a cutting path,  
       [0033] scanning means for scanning the tissues of the body part ahead of the cutting location of the cutting means, the scanning means being operative to generate data signals including data pertaining to the location and/or conformation of internal structures of the body part,  
       [0034] processing means for processing the data signals from the scanning means and being operative to generate control signals dependent on the location and/or confirmation of the internal structures, and  
       [0035] control means operative in response to the control signals to control the position of the cutting means during the cutting operation in at least two degrees of freedom so as to cut the body part along the cutting path dependent on the conformation of the internal structures.  
       [0036] The scanning means preferably comprises an ultrasonic scanner operative to generate ultrasonic pulses within the body part, the ultrasonic scanner including a source arranged to be progressively advanced along to the surface of the body parts and an associated detector which is provided and located to detect reflected or echo signals from interfaces between internal tissue structures having differing densities, the detector being operative to venerate the data signals. The detector of the scanning means is preferably operative to detect echoes of ultrasonic signals reflected at interfaces between bone and other tissues, the processing means being operative to determine from the data signals information about locations and conformations of bone within the body part.  
       [0037] In a particular preferred embodiment, the body part comprises the carcass of a slaughtered animal, and the cutting means comprises splitting means operative to split the carcass into two halves by cutting alone the centre line of the spine, the processing means being operative to analyse the data signals from the detector to locate the centre of the spine and to provide feedback control signals for controlling automatically the position of the splitting means as it follows the scanner alone the line of the spine. In this embodiment, the moving means preferably includes advancing drive means for advancing the splitting means long the general longitudinal line of the spine, the control means including positioning means operative in response to the control signals, the positioning means comprising at least two of:  
       [0038] lateral positioning means operative in response to the control signals to selectively move the splitting means laterally relative to the longitudinal line of the spine of a carcass as the splitting means is advanced by the advancing drive means,  
       [0039] roll positioning means operative in response to the control signals to vary the inclination of the plane of the instantaneous direction of splitting to the longitudinal line of the spine, and  
       [0040] tilt positioning means operative in response to the control signals to tilt the splitting means about an axis orthogonal to the plane of advancing movement of the splitting means along the spine of the carcass.  
       [0041] The cutting means may be moveable along lee cutting path at a variable speed, and the processing means may generate speed control signals for controlling the speed of advance of the cutting means depending upon the type and/or density and/or dimensions of the tissues being cut. 
     
    
    
     [0042] Possible and preferred features of the third and fourth aspects of the present invention will now be described with particular reference to the accompanying drawings. However it is to be understood that the features illustrated in and described with reference to the drawings are not to be construed as limiting on the scope of the invention. In the drawings:  
     [0043]FIG. 1 is a perspective view of a carcass splitting apparatus embodying the third and fourth aspects of the present invention,  
     [0044]FIG. 2 is a perspective view of the splitting means used in the apparatus of FIG. 1,  
     [0045]FIG. 3 is a view of the splitting means similar to FIG. 4 showing a tilting means operated,  
     [0046]FIG. 4 is a side elevation of the apparatus at the splitting station prior to use,  
     [0047]FIG. 5 is a side view showing leaning means operated to advance the splitting means towards an operative position,  
     [0048]FIG. 6 is a side view of the apparatus showing, the splitting means tilted and advancing positioning, means operated to advance the splitting means and scanning means to positions ready for commencement of the splitting operation,  
     [0049]FIG. 7 shows a position of the splitting means at an early stage of the splitting operation,  
     [0050]FIG. 8 shows the splitting means after having split the carcass and reached the end of its vertical travel, and  
     [0051]FIG. 9 shows the splitting means after having been retracted. 
    
    
     [0052] Referring to FIG. 4 of the drawings there is illustrated a beef carcass  10  suspended on hooks  11  (one in each hind leg  12 ) from an overhead rail  11 . This is a conventional way of suspending a carcass in a meat processing plant. The carcass  10  has had the head, tail and hide removed, the carcass has been eviscerated, and the sternum or brisket has been split preparatory to the carcass splitting operation.  
     [0053] At a splitting station on the carcass processing line, there is provided a splitting apparatus  15 . The apparatus  15  includes a main support  16  which extends generally upright and which supports a carcass splitter assembly  17  during its splitting operation. The assembly  17  includes a saw blade  18  which in the illustrated embodiment comprises a band saw although the invention is also applicable to other splitting mechanisms including reciprocating saws, circular saws, and also cleavers (frequently used for splitting pig carcasses). In the illustrated embodiment, the saw blade  18  has an associated drive  19  near the support  16  and the blade  18  runs around inside an inner shroud  21  and an outer shroud  20  spaced outwardly from the support  16 .  
     [0054] The splitter assembly  17  is mounted on a carriage  22  which is selectively movable vertically along, the support  16  e.g. along tracks  23 . For this purpose a vertical motion drive  24  can be provided associated with the carriage  22  for driving the carcass splitter assembly  17  generally vertically on the support  16 . During a carcass splitting operation, as fully described later, the drive  24  will move the carriage  22  and saw  18  from a raised position in a downwards direction so as to split the carcass starting at the tail and moving in the cranial direction downwardly.  
     [0055] Also associated with the carriage  22  there may be a carcass support  65  which bears against the carcass, e.g. so as to bear some weight of the carcass. The carcass support  65  may comprise spaced rollers  66  or guides which bear against the dorsal surface of a carcass and straddle the spine and being positioned so that the rollers bear some weight of the carcass by pressing in a direction away from the support  16 , whereby a positive and secure centring location of the carcass is achieved or at least assisted by the rollers  66 . The saw blade  18  can cut through the spine by following in close proximity to the rollers  66  so that the spine is positively restrained against lateral movement in the region where the saw blade  18  is cutting the spines. Such an arrangement of guide rollers is further described in U.S. Pat. No. 5,312,292.  
     [0056] Mounted and positioned so as to move alone the spine of the carcass in advance of the cutting blade  18  is a scanner  30 . In a preferred embodiment the scanner  30  is an ultrasonic device which contacts the dorsal surface of the carcass  10  a short distance in advance of the saw blade  18 . An ultrasonic transducer  31  generates ultrasonic pulses at the carcass surface which propagate through the tissues. Echoes or reflections of the ultrasonic pulses arise at density, discontinuities within the carcass tissues. Because of the pronounced density discontinuity that occurs at the interface between bone tissue of the spinuous process of the spine and adjacent other tissues, such as connective tissue, muscle tissue, or fat tissue, there is strong signal reflection at the surfaces of the spine. The transducer  31  detects and generates data signals on line  71  in response to the reflected pulses and by providing processing means  70  operative to analyse these reflected pulses it is possible to determine characteristics of the spine e.g. of the location and conformation. For example, it is possible to determine the centre line of the spine alone, which it is intended the saw blade  18  will cut. It is not necessary to provide a configuration of ultrasonic transmitters and ultrasonic detectors in the transducer  31  and associated processing circuitry or software of processing means  70  to be able to accurately determine the complete profile of the spine—it is merely preferred to determine the centre line. Therefore, it may be sufficient to have a single pulse transmitter travelling substantially along the spine ahead of the saw blade  18  and a detector or two detectors adjacent or on opposite sides of the spline. The symmetry of detected reflected pulses may be sufficient for suitable analysing means  70  to determine the centre line without it being necessary to attempt to determine a detailed conformation of the spine.  
     [0057] The analysis of ultrasonic pulse reflections from animal tissues is a well developed technology and is used for example in determining back fat depths in animals for grading purposes. Therefore, the types of ultrasonic transducers, their configuration, the circuitry and software to analyse the detected signals can all be determined by a person skilled in the art of use of ultrasonic transducers. Alternatively, suitable configurations of transducers and processing circuitry or software can be empirically determined.  
     [0058] It is desirable to achieve good acoustic coupling between the transducer  31  and the dorsal surface of the carcass  10 . Since it may not be acceptable to apply some known acoustic coupling materials such as some oils to meat products for human consumption in the present invention it may be preferred to spray sterile water onto the carcass  10  in the vicinity of the transducer  31  to achieve good acoustic coupling. The splitting assembly  17  may include a water spray device located to s-tray the surface of the carcass near or just ahead of he transducer  31 .  
     [0059] By operation of the processing means  70  in analysing the detected data signals on line  70  from the transducer  31 , and determining the centre line of the spine, it is possible to then generate control signals on lines  72 ,  73 ,  74 ,  75  to control the position of the saw blade  18  which is moving relative to the carcass a short distance behind the transducer  31 .  
     [0060] For example, if the centre line of the spine is determined to be shifting laterally (i.e. in a direction orthogonal to the upright plane in icy he sa blade  18  is travelling and which is assumed to be the median plane of the carcass) from here the saw blade is presently located, the control signals generated on line  75  can be used to move the lateral position of the saw blade  18  to maintain it centred as it moves along the spine. For this purpose the apparatus includes a lateral positioning means  35  (obscured behind the inner shroud  21  and carriage  22 ) operative to selectively move the saw assembly  18 ,  19 ,  20  laterally relative to the carcass  10 . As best seen in FIGS. 2 and 3, the splitter assembly, which is mounted on carriage  22 , includes a base frame  40  and a sub-frame  41 . The base frame  40  is mounted by the carriage  22  so as to be capable of advancing and retracting movement (in the direction of arrow B in FIG. 2) as further described later. The sub-frame  41 , to which the saw assembly  18 ,  19 ,  20  is mounted, is, in turn, movably mounted to the base frame  40  by the lateral positioning means  35 . The lateral positioning means  35  is operative to selectively move the sub-frame  41  linearly towards and away from the base frame  40 , i.e. in the direction of arrows A, orthogonal to the vertical plane in which the saw blade  18  travels. With this arrangement, the lateral positioning means  35  can respond to control signals to position the saw blade  18  to follow the centre line of the spine even if the spine centre line deviates laterally along its length. It may be found that lateral movement of a maximum of several centimetres may be sufficient for practical operations in splitting of animal carcasses. The lateral positioning means  35  may comprise any convenient means such as for example a pneumatic or hydraulic rant mounted by the base frame  40  and coupled to the sub-frame  41  for moving the sub-frame  41  towards and away from the base frame  40 .  
     [0061] As mentioned earlier the base frame  40  is capable of advancing and retracting movement is the carriage  29  so as to advance and retract the saw assembly  18 ,  19 ,  20 . This advancing and retracting movement may be achieved by any convenient drive means  38  operating between the base frame  40  and the carriage  22 . The advancing and retracting movement is not primarily designed as a degree of movement of the splitting means for control of the splitting operation but is intended more for positioning the splitting assemble preparatory to commencing the splitting operation and at the end of the splitting operation, as will be further described later in connection with the sequence depicted from FIG. 4 to FIG. 9 of the drawings.  
     [0062] A further degree of movement of the saw blade  18  that may be desirable to provide additional control of the carcass splitting operation is a roll control. By “roll” is meant the inclination of the plane of the instantaneous cutting direction to the vertical.  
     [0063] In FIG. 2 in particular there is illustrated schematically a roll positioning means  45  operative in response to control signals on line  74  from the means  70  processing the data signals  71  from the transducer  31 . The roll positioning means  45  is operative to change the instantaneous cutting direction of the saw blade  18 . The roll positioning means  45  includes a mounting bearing  46  through which the saw assembly  18 ,  19 ,  20  is mounted to the sub-frame  41  for limited rolling movement, i.e. angular movement of the saw assembly  18 ,  19 ,  20  about an axis generally collinear with the line of the saw blade  18 . This direction of rolling movement is illustrated by the arrow C in FIG. 2. To achieve the selective angular moment of the saw assembly in the directions of arrow C, the apparatus includes a selectively operated rotary drive  47  to move the saw assembly  18 ,  19 ,  20  angularly in its mounting bearing  46 .  
     [0064] The roll positioning means  45  would normally be used during a splitting operation in conjunction with operation of the lateral positioning means  35 . For example, if the spine of the carcass bends laterally before straightening again to descend vertically, the data signals  71  front the scanner can be processed by means  70  to detect the deviation and generate control signals on lines  74 ,  75  to both the lateral positioning means  35  and the roll positioning means  45 . By rolling the saw assembly to change the plane of cutting of the blade  18  and simultaneously causing the lateral positioning means  35  to laterally move the saw assembly  18 ,  19 ,  20 , the line of splitting can accurately follow the line of the spine as it deviates laterally and again as it deviates again to resume a vertical line. By simultaneously rolling and laterally moving the blade, the mechanical stresses to which the blade  18  would be subjected by lateral movement alone or by rolling movement alone can be substantially reduced or eliminated, thereby reducing or eliminating breakage of the band saw  18  by following a crooked spine.  
     [0065] A further degree of movement of the saw blade  18  that is provided in the illustrated embodiment is a tilt control, i.e. controlling the inclination of the blade to the horizontal during a vertical splitting operation. As shown in FIG. 3 by comparison with FIG. 29 the apparatus includes a tilt positioning means  50  which is operative in response to control signals on line  73  to selectively tilt the saw blade  18  about a generally horizontal axis orthogonal to the plane of the cutting of the saw blade. i.e. to tilt the blade  18  in the direction of arrows D in FIG. 3. The tilt positioning means  50  in the illustrated apparatus includes a pneumatic or hydraulic ram  51  operable between the base frame  40  and a part of the saw assembly  18 ,  19 ,  20  displaced from the axis around which the tilting movement occurs. In FIG. 3 the tilting movement in the direction of arrows D occurs about the axis of the drive means  19 . The point at which the ram  51  is coupled to the saw assembly call be a point on the inner shroud  21 . The degree of movement of the saw blade  18  achieved by the tilt positioning means  50  can be useful in positioning the saw assembly for the commencement of a splitting operation and to start the splitting of the spine more safely and more reliably by using an inclined line of approach of the saw blade up to the initial point of contact with the spine at the base of the spine where the tail has been previously removed. This is illustrated in FIG. 6 and, as shown in FIG. 7, the tilt positioning means  50  can be operated to bring the saw back to a horizontal position when the splitting of the spine has proceeded beyond the lumbar region.  
     [0066] As mentioned earlier, the carriage  22  is selectively movable alone the upright main support  16  so as to carry out the splitting operation. Any convenient drive means  24  can be used to provide the vertical degree of movement of the saw blade. The vertical movement can be controlled by a predetermined program so as to achieve a predetermined throughput of carcasses.  
     [0067] The speed of vertical movement of the saw blade  18  controlled by the associated drive  24  can also be responsive at least in part to the means  70  processing the data signals  71  from the transducer  31 . These data signals for example may provide some data about the extent of bone tissue and/or density of bone tissue so that an optimum speed of advance of the carcass splitting can be achieved. In addition or alternatively, means sensing the resistance to the advancing splitting blade  18  can provide feedback information to control the speed of vertical movement of the splitter assembly  17 . Speed control signals to the drive  24  are generated on line  72  (FIG. 2).  
     [0068] A further possible degree of movement of the saw blade  18 , although not one which is provided in the illustrated embodiment, is yaw control. It is possible to provide in the apparatus a yaw positioning means to selectively vary the angle of the blade by selective angular movement thereof about a vertical line. Then seen in plan view, the saw blade  18  can be angularly moved by an appropriate yaw positioning means to maintain accurate central splitting through the spine and carcass, particularly if there is some twisting of the spine along its length.  
     [0069] FIGS.  4  to  9  illustrate in side view a sequence of positions of the apparatus during a carcass splitting operation. It will be possible to better understand the method and apparatus of the present invention by reference to these drawings and the following description.  
     [0070] In FIG. 4, the apparatus is shown in a preliminary or standby position awaiting arrival of a carcass  10  suspended in conventional manner by its hind legs  12  from rail  13 . When the carcass arrives at the splitting station in wrong of the apparatus, the splitter assembly  17  will be positioned between the spaced hind legs  12 .  
     [0071] As shown in FIG. 4, the main support  16  is in a leant back position. This is achieved by providing a pivotal mounting  60  of the support  16  at floor level. A lean positioning means  61  is provided at the upper end of the support  16  and comprises spaced guide members  62  between which the top end of the support  16  moves. A pneumatic or hydraulic ram (or other suitable drive)  63  is selectively operated to draw the support  16  from its leant back position shown in FIG. 4 to its upright “leant forward” position shown in FIG. 5 when the carcass  10  has arrived and is located in its desired position at the splitting station. As shown in FIG. 5 the assembly  17  is then positioned between the hind legs  12  of the carcass  10  but is still in a retracted position.  
     [0072] As shown in FIG. 6, compared to FIG. 5, the tilt positioning means  50  can be operated to tilt the saw assembly upwardly to its inclined position shown in FIG. 6. At the same time, or subsequently, the advancing positioning means  38  is operated to advance the base frame  40  within the carriage  22  whereby the scanning means  30  is brought into operative association with the carcass  10 , the scanning means  30  being positioned a short distance below the base of the spine where the tail has been removed and where the splitting operation will commence. During advancing movement of the saw assembly into the position shown in FIG. 6, the carcass lateral restraint rollers  66  or the other means to restrain the carcass against free lateral or other movements can also be advanced to adopt their operative positions engaging the carcass and straddling the spine (although for convenience in FIGS. 6 and 7 the rollers  66  are shown still retracted). The saw assembly is then operated and is moved downwardly by movement of the carriage  22  along the support  16  so that the saw blade  18  commences the splitting operation at the base of the spine and progressively advances downwardly following the line of the spine of the carcass as shown in FIG. 7. During this operation, the tilt positioning means  50  can be operated to bring the saw  18  back to a generally horizontal position.  
     [0073] During the splitting operation, the scanning means  30  follows the spine of the carcass, and the data signals on line  71  from the scanning means  30  are processed in processing means  70  to locate the spine and/or determine its conformation immediately ahead of the point where the saw  18  is splitting the carcass. The control signals on lines  72 ,  73 ,  74 ,  75  from the processing means  70  ale used to control the decrees of movement of the saw blade including (in the preferred embodiment) lateral movement (the direction of arrows A), rolling movement (the direction of arrows C), vertical movement and, if desired, tilting movement (the direction of arrows D).  
     [0074] When the saw assembly passes beyond the carcass and reaches the end of its vertical travel shown in FIG. 8 completing the splitting operation, the advance positioning means  38  can be operated to retract the saw assembly back towards the support  16  as shown in FIG. 9. The carcass halves now being separated and being suspended from their respective hooks can be advanced away from the splitting station suspended from the overhead rail  13  and past the saw assembly. He saw assembly in the position shown in FIG. 9 can be washed and sterilised by hot water as known in the industry. After this, the splitting assembly can be raised back up the support  16  and the support  16  can be leant back so the apparatus is returned to the position shown in FIG. 4 preparatory to arrival of the next carcass.  
     [0075] It will be seen that the process and apparatus for splitting carcasses of slaughtered animals according to the invention particularly as described herein in relation to the drawings, call enable accurate splitting of the carcasses along the centre line of the spine despite significant variations in characteristics and structure of successive carcasses. Not only individual differences between particular animal carcasses, but also between different ages and breeds of animals can be accommodated. Of course, gross difference, such as differences between animal species may require different processing circuitry or software for determining the respective centre lines of the spines but the principles of the process and apparatus of the present invention nevertheless remain the same.  
     [0076] It will also be seen that the process and apparatus for splitting carcasses of slaughtered animals according to the invention as described herein in relation to the drawings can be modified and adapted to enable automatic cutting of a human or animal body part along, a path that is dependent on the internal tissue structures. In fact the method and apparatus can be further generalised in its uses to automatically cut products having an internal structure to be considered in determining the paths of the cuts, such products including natural products such as plant matter (fruit, vegetables, timber, etc.) and animal matter (for medical/surgical or veterinary purposes or procedures, including forensic procedures) and also for cutting manufactured products, artefacts, archaeological articles.  
     [0077] When used in this specification and claims, the terms “comprises” and “comprising” and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.