METHOD FOR PROVIDING A CUT AROUND THE ANUS OF AN ANIMAL, WHICH IS SUSPENDED FROM ITS BACK FEET, TO FREE THE RECTUM FROM THE CARCASS, AND APPARATUS FOR PERFORMING SAID METHOD

Abstract: Method for providing a cut around the anus of an animal, preferably a hog, to free the rectum from the carcass, which is suspended at its back feet, according to which method a rotating, tubular knife (10) is advanced towards the anus of the animal for making a cut around it in a predetermined depth. With the purpose of obtaining an automatized cutting process to free the rectum of animals, which may vary as to size and also be individually different, the method is characteristic in that the carcass is fixed with respect to a vertical plane through the axis of the knife (10), that the hind part of the carcass is fixed with respect to a vertical plane perpendicular to the first plane, that a linear sensor (20) parallel with the second plane is moved downwards in a substantially vertical direction in such a distance from the second plane that it hits the root of the animals tail, and that the rotating knife (10) is adjusted to a predetermined position with respect to the sensor (20) when it is hitting the root of the tail, after which the sensor (20) is moved to an inactive position out of the way of the knife (10), whereafter the cut is made.

Description: Method for providing a cut around the anus of an animal, which is suspended from its back feet, to free the rectum from the carcass, and apparatus for performing said method. The present invention relates to a method for providing a cut around the anus of an animal to free the rectum from a carcass suspended from both its back feet and is of the kind disclosed in the preamble of claim 1. Furthermore, the invention relates to an apparatus for carrying out said method. On slaughter lines the carcasses are normally conveyed along the line suspended from their back feet. This goes in particular for hogs, for which particular kind of animal slaughter lines with many partially automatized functions have been established. After scalding and removal of the outer layer of skin by means of hair shoving, black- singing and scraping the animals are opened. One of the first stages of the opening is to free the rectum at the anus. The rectum is connected to the skin and should be cut free in such a way that it is not damaged. For this purpose a cut is performed by means of a knife around the rectum. On slaughter lines of the known type the cutting takes place manually, and it is a very labour-demanding operation, which is considered ergonomically difficult on account of the fact that a round cut is to be made with the slaughter knife. As an alternative to the slaughter knife an air pistol with a rotating cutting tube, which is manually taken down to the anus, thus cutting free the rectum. Even with the air pistol the cutting is a demanding and time- consuming operation. The object of the invention is to provide a method, by means of which the cutting free of the rectum can be automatized. This object is met according to the invention by means of the subject matter of the characterizing clause of claim 1. The invention is based on the observation that when carcasses are suspended from both their back feet, the distance in vertical direction between the root of the animal's tail and the anus is subject to only small variations. These variations are so small that the knife may be adjusted to its cutting position already on basis of measurement of the position of the root of the tail, and thenm advanced axially on condition that the animal before and after the measurement is fixed in such a way that the root of the tail may be hit by a simple movement of the sensor. This requirement is met if the animal is fixed by means of a fixation means pressing against its back in the hind part of the animal. Preferably, the knife is provided with a gauge, which during the cutting process is introduced into the anus, and which in particular prevents a wrong positioning of a cut in an animal, the dimensions of which differ from normal. The gauge may be used for activating the advancing of a new carcass, the adjustment of the knife being changed slightly, before the new operation is started. If the operation fails, an alarm may start, and the operation may then be carried out manually. When the rectum has been cut free, the known position of the animal and the opening made by the cutting may be used for the introduction of a knife with a ball-point and for dividing the crutch of the animal, thus avoiding one more labour-consuming and awkward working process. The apparatus according to the invention is defined in claims 6-10. The invention will be described in detail with reference to the accompanying drawing, in which: Fig. 1 shows a section through an embodiment of the apparatus according to the invention and through the conveying means on a slaughter line, and fig. 2 shows a section thorugh the apparatus along the line II-II according to fig. 1. The embodiment shown in the drawing of an apparatus for providing a cut around the anus of a carcass for freeing the rectum comprises a supporting frame 1 connected with a support rail 2 for carcasses, which are suspended from both their back feet by means of hooks 4 arranged in pairs. The support rail 2 may run through the major part of a slaughter line. The hooks 4 are mounted in a predetermined distance from one another by means of fixation means in each pair of hooks. Along the support rail positioning means 5 are arranged, said means being adapted to advance the carcasses along the support rail 2 and for fixing the animals for as long as required at each working station. The support frame 1 comprises a pair of vertical positioning columns 6, along which a support frame is displaceable in vertical direction. The support frame is displaced by means of a hydraulic cylinder 8 or corresponding driving means connected to the upper part of the support frame. A positioning means 9 for a rotating knife 10 provided with driving means 11 is pivotally mounted on the support frame. The positioning means is pivotal in vertical direction around a swinging shaft 11 by means of a hydraulic cylinder 12, the piston 13 of which is connected to a console 14 on the positioning means 9. By means of the hydraulic cylinder it is possible to change the angle of the axis of the rotating knife from approx. 45° as shown in the drawing to approx. 60° with the horizontal plane. The rotating knife 10 comprises a centrally placed gauge 15 protruding somewhat in relation to the edge of the knife. Besides an advancing means 16 for a knife 17 with a ball- shaped point is pivotally connected to the frame. The angle of the advancing means 16 is adjustable by means of a hydraulic cylinder, which is not visible in fig. 1 on account of the cylinder 12, and the piston 18 of which is in gear with a console 19 placed on the advancing means 16. From fig. 2 it can be seen how the two advancing means are mounted side by side on the support frame 7. On the support frame a sensor arm 20 is placed, which is arranged for adjusting the height of the support frame. The sensor arm is pivotal around a horizontal axis by means of a driving means 21, which allows it apart from the horizontal position shown in the drawing to take up an inactive, vertical position. The sensor arm is provided with a contact sensor, by means of which a signal is emitted for the activation of the cutting operation. In the lower part of the animal's body fixation means 22 is pressing against the back of the carcass, when it is positioned in front of the apparatus described above. By means of the apparatus an automatic free-cutting of the rectum of the carcass can be carried out while using the method according to the invention. At the end of a working operation the apparatus is positioned in its uppermost position, in which the piston of the cylinder 6 is withdrawn into the cylinder. By means of the driving means 6 a carcass 3 is placed and fixed in front of the apparatus. During the fixation the carcass is pushed slightly away from the apparatus by means of the fixation means 22 dependent on the size and shape of the animal, but in all cases so much that the carcass is resting against the fixation means. On account of this the hind of the carcass will, irregardless of the size of the animal, be fixed in such a way that within very narrow limits the tail of the carcass will be positioned in a certain vertical plane in front of the apparatus. Then the support frame 7 is lowered, until the sensor arm 20, which has taken up a horizontal position, gets in contact with the root of the animal's tail. The contact activates the contact sensor, which starts the cutting operation. At first the sensor arm is pivoted into a vertical position, then the rotating knife is advanced towards the animal, until the gauge 15 penetrates about 20 mm into the anus of the animal. The hollow space in the inside of the knife is now connected to a vacuum source in order to suck up any content from the rectum, which may get out during the subsequent cutting. Then the knife is tilted to a position, in which it is at an angle of 60° to the horizontal plane during the further advancing of the knife 10. When a predetermined cutting depth has been reached, the rectum is cut free, and the rotating knife can be withdrawn. The rotating knife comprises desinfecting menas, which are activated after each cutting operation, preferably when no carcass is present in front of the apparatus. After the cutting operation the rotating knife is brought back into the position, in which it forms an angle of 45° to the horizontal plane. The apparatus is in the preferred embodiment provided with a cutting device, which divides the animal through the crutch. The cutting device comprising the advancing means 16 is tilted into a position, in which it forms an angle of approx. 45° to the horizontal plane. Then the knife 17 is brought forward into the cut in the animal just made. When the advancing means has returned to the position shown in the drawing, the knife 17 will divide the carcass through the crutch, after which the knife returns to its starting position. Finally, the support frame returns to its starting position, in which the sensor arm is lifted from the carcass, and the carcass is then conveyed further down the line by means of driving means 5, and a new operation may be initiated, when a new carcass is brought into position in front of the apparatus.

Claims: Claims 1. Method for providing a cut around the anus of an animal, preferably a hog, to free the rectum from the carcass, which is suspended at its back feet, according to which method a rotating, tubular knife is advanced towards the anus of the animal for making a cut around it in a predeterminded depth, c h a r a c t e r i z e d in that the carcass is fixed with respect to a vertical plane through the axis of the knife, that the hind part of the carcass is fixed with respect to a vertical plane perpendicular to the first plane, that a linear sensor parallel with the second plane is moved downwards in a substantially vertical direction in such a distance from the second plane that it hits the root of the animals tail, and that the rotating knife is adjusted to af predetermined position with respect to the sensor, when it is hitting the root of the tail, after which the sensor is moved to an inactive position out of the way of the knife, whereafter the cut is made. 2. Method according to claim 1, c h a r a c t e r¬ i z e d in that the rotating knife is moved synchroneously with the sensor, the sensor and the knife being mounted on a common frame, which is movable in a substantially vertical direction, and that the sensor is pivoting around a horizontal axis from a horizontal measuring position to an inactive vertical position. 3. Method according to claim 1 or 2, c h a r a c t- e r i z e d in that the rotating knife comprising a coaxial gauge, which protrudes in front of the knife, is advanced in an angle of 45° with horizontal, until the gauge is introduced approximately 20 mm into the anus, whereafter the interior of the knife is connected with a vacuum source during the cutting around the anus. 4. Method according to claim 3, c h a r a c t e r¬ i z e d in that the angle between the axis of the knife and horizontal during the cutting to approximately 60 . 5. Method according to any of the claims 1-4, c h a r a c t e r i z e d in that a knife with a ball- shaped point after the cutting around the anus is introduced into the hole and moved upwards in a pivoting movement in such a way that the carcass is divided in the crutch. 6. Apparatus for providing a cut around the anus of an animal, preferably a hog, in accordance with the method described in claim 1 to free it from the carcass, which is suspended at its back feet, which apparatus comprises a rotating, tubular knife adapted for being advanced towards the anus of an animal anus for making.a cut around it in a predeterminded depth, c h a r a c t e r i z e d in supporting and positioning means, which are movable in a substantially vertical direction, and in which the knife is axially movable for performing the cut, the supporting means being arranged in front of fixation means for fixation of the suspension hooks and in front of fixation means pressing against the back of the carcass in the hind area, the supporting means comprising a linear sensor, which is movable in a substantially vertical direction and means for registering contact with the root of the tail of the carcass and to adjust the rotating knife in a predetermined position with respect to the sensor, which sensor is movable to an inactive position out of way of the rotating knife. 7. Apparatus according to claim 6, c h a r a c t¬ e r i z e d in that the sensor and the rotating knife are mounted in a fixed relationship on the supporting and positioning means, which means are movable in substantially vertical direction, and that the sensor is pivotable around a horizontal axis parallel with a vertical plane through the axis of the rotating knife. 8. Apparatus according to claim 6 or 7, c h a r¬ a c t e r i z e d in that the rotating knife comprises a central and coaxial gauge protruding in front of the edge of the knife, and that the rotating knife is mounted on an advancing means, which is pivotable from a position, in which it forms an angle of 45°, to a position in which the angle is 60° with a horizontal plane. 9. Apparatus according to claim 6, 7 or 8, c h a r a c t e r i z e d in that the portion of the sensor, which is making contact with the root of the tail of the amnimal, is a horizontal rod provided with af contact sensor with means for activating the cutting operation. 10. Apparatus according to any of the claims 6-9, c h a r a c t e r i z e d in further comprising a knife with a ball-shaped point and with advancing means for moving the knife to substantially the same position as the rotating knife, which knife has means for making an upwards pivotal movement when in its advanced position.

Inventors: ANDERSEN BOERGE CHRISTIAN, ANDERSEN, BOERGE, CHRISTIAN
Applicants: NUTRIDAN ENG AS, NUTRIDAN ENGINEERING A/S
Application year: 1989
Main classification: A22B5
IPC codes: A22B5