Method and apparatus for preparing a pig's head for mechanical boning

Abstract: The present invention relates to a method and an apparatus for preparing a pig's head for mechanical boning. A transverse cut in the snout is made from the underside of the head, wherein the cut extends between the rostrale bone (os rostrale) and the jaw bone (os incisivum). Preferrably a longitudinal saw-cut extending in the nose bone (os nasale) is made in the snout. It is also possible to make a longitudinal cut through the rind -in the middle of the upperside of the head. The invention also relates to an apparatus for executing the above method.

Description: The present invention relates to a method for preparing a pig's head for mechanical boning and also to an apparatus for preparing a pig's head for mechanical boning. In mechanical boning of a pig's head use is usually made (see WO-A-88/07329) of a boning line wherein the pig's head is placed on a carrier and wherein butchering operations are performed on the pig's head in diverse stations of the boning line. It is important herefor that the pig's head is placed on a carrier and that this carrier is guided together with the pig's head along the various stations. Since at the stations of the boning line great forces are typically applied to the pig's head in respect of removing pieces of meat and the like from the bone of the pig's head, it is important that the pig's head is fixed firmly on the carrier. The object of the present invention is to provide a method and a device for preparing a pig's head for mechanical boning which enables fixing of the thus prepared pig's head on a carrier with which the pig's head is carried along a boning line. This object is achieved by the method of claim 1 and the apparatus of claim 5. As a result of these steps it is possible to separate the rostral bone from the nose bone so that the mask can be at least partially removed. After performing this operation several cavities have been opened so that it is possible to place the pig's head on a carrier such that the pig's head is sufficiently fixed for operations to be carried out during the boning process. Moreover, when the mask is pulled away sufficiently far, a considerable portion of the bone of the head is exposed, which likewise offers possibilities for fixation. An advantage of the above device lies in the fact that the rostral bone separated from the remaining skeleton forms a good gripping point for pulling loose the mask. This step facilitates the pulling loose of the mask from the head. Making a cut in the snout in lengthwise direction which extends into the nose bone (os nasale) improves the accessibility of the nasal cavity. According to a preferred embodiment the device comprises a saw-blade which is driven in rotation and movable into the snout in a path extending in lengthwise direction of the head from the front of the snout, and which protrudes at least partially above the support plate. According to a preferred embodiment a cut extending in lengthwise direction is made through the rind in the middle of the upper part of the head. According to another preferred embodiment the device comprises a knife-blade which is driven in rotation and movable through a gap arranged in the support plate and which is adapted for cutting along the upper part of the head through the rind substantially to the bone. It becomes easier herewith to pull the mask off the pig's head at one of the first stations of the subsequent butchering line. The present invention will subsequently be elucidated with reference to the annexed drawings, in which: fig. 1 shows a cross sectional view of a device according to the present invention; fig. 2 is a top view of the device depicted in fig. 1; fig. 3 is a detailed cross sectional view of the device depicted in fig. 1; fig. 4 is a cross sectional view of a cutting member used with the device shown in fig. 1; and fig. 5 shows a cross section of the cutting member depicted in fig. 4. The device shown in fig. 1 is formed by a casing 1 which is closed on its top by a plate 2 and which rests on the ground on its bottom by means of adjustable legs 3. In preference the casing is manufactured from stainless steel to enable easy cleaning. Arranged on top plate 2 is a support plate 4 extending partially thereabove which is provided with a recess 5 for positioning of the pig's head 6 for preparing. Forward of the position where the pig's head comes to rest is arranged a set of switches 7 which detect whether a pig's head is present. Above the other part of upper plate 2 is a cover 8. Fixed to the cover 8 is a support 9 to which a pneumatic cylinder 10 is attached. A cutting member in the form of a cleaving knife 11 is fixed to the piston rod of the pneumatic cylinder. In the middle of support plate 4 a continuous slot 12 is arranged, as shown in fig. 2. The slot 12 otherwise also extends through the greater part of upper plate 2 and through the front wall of cover 8. Arranged in the interior of the casing 1 against the bottom 13 of casing 1 is a support 14 to which a second lever 15 is fixed rotatably. Fastened rotatably to one end of the second lever 15 is a first lever 16, to the other end of which is fixed a round knife 17 drivable in rotation. The knife-blade 17 is drivable by means of a hydromotor 18 fixed on the first lever 16. In addition the other side of the second lever 15 is connected to the piston rod of a pneumatic cylinder 19 which is attached with its fixed end to the front wall 20 of casing 1. When the pneumatic cylinder 19 is energized the rotatably drivable knife-blade 17 will thus be moved upward, wherein the knife-blade extends through the slot 12. For movement in substantially horizontal direction is arranged a pneumatic cylinder 21 which is rotatably connected with its fixed end to a support 22 fixed to the upper plate 2. The piston rod 23 of this pneumatic cylinder 21 is connected to the first lever 16. When the pneumatic cylinder 21 is energized the rotatable knife-blade 17 is moved in substantially horizontal direction. Finally, against the bottom 13 is arranged another support 24 to which a third lever 25 is rotatably fastened. Fixed to the free end of the third lever 25 is a rotatably drivable saw-blade 26. The rotatably drivable saw-blade 26 is drivable by a hydromotor 27. The third lever 25 is provided with a pin 28 which extends through a slot 30 arranged in a fourth lever 29. The third lever 25 will thus follow the movements of lever 16, albeit with a free stroke which is caused by the length of slot 30. As a result the rotatably drivable saw-blade 26 will follow with the same free stroke in horizontal direction the movements in horizontal direction of the rotatably drivable knife-blade 17. Arranged above support plate 4 and in particular above the recess 5 is a protective cage 31 which ensures that, when a head for processing is present, the user cannot move with his hands into the vicinity of the cleaving knife 11, knife-blade 17 or saw-blade 27. As extra safety precaution safety switches 32 are arranged on the sides of cage 31, wherein the driving and the movement of said sawing, cleaving and cutting implements is only possible when these switches 32 are pressed in. The distance between both switches 32 is such that they cannot be pressed in with one hand, so that the user needs both hands to press in the switches and cannot therefore move his hands into the vicinity of the dangerous components. The operation of the device according to the invention will now be elucidated. Firstly, a pig's head 6 is placed on the upper plate 2, this as far as possible into the cavity 5, as shown in fig. 3. The snout 33 of the pig's head herein rests against the detection switches 7 so that the presence of the pig's head 6 is detected and so that it is possible after pressing in the safety switches 32 to set the cutting, cleaving and sawing implements into operation. The pneumatic cylinder 19 is first energized so that the lever 16 is moved wholly upward, wherein pressure is also supplied to the hydromotor 18. As a result thereof the knife-blade 17 will begin to rotate. The rotating knife-blade 17 will herein cut into the pig's head 6. The depth of the cut depends on the force with which cylinder 19 is energized. This force is selected such that the cut extends into the rind but not, or only to a small extent, into the nose bone. The pneumatic cylinder 21 will herein likewise be energized so that the rotating knife-blade 17 will displace in horizontal direction, wherein the pressure exerted by the pneumatic cylinder 19 is such that the contour of the nose bone 39 is followed and that only the rind 38 is cut through. This operation is important for removing the mask during the following butchering procedure. During the horizontal movement of knife-blade 17 this movement, after a certain dead zone dependent on the length of slot 30, is transmitted by means of levers 16,29,25 to the rotating saw-blade 26. This is of course driven in rotation by the hydromotor 27. The rotating saw-blade herein makes a saw cut through both the rostral bone 34 and the jaw-bone 35. The snout of the pig's head is hereby sawn into two pieces, which facilitates gripping by gripper members during the subsequent butchering operation for removal of the mask. Furthermore, by sawing the rostral bone 34 and the jaw-bone 35 each into two pieces placing of the pig's head onto the pins is likewise facilitated. Air is then fed to the pneumatic cylinder 10 so that the cleaving knife 11 moves downward and cuts through the snout 33 of the pig, doing this between the rostral bone 34 and jaw-bone 35. The cartilage 36 present therebetween is herein cut through. As a result the rostral bone 34 comes loose so that in principle it is possible to place the thus treated pig's head 6 on pins which extend into the nasal cavity 37. Reference is made in the above embodiment to pneumatically driven cylinders. It will be apparent that these can be replaced by hydraulically driven cylinders or by other linear drive members. It should be noted here that it is less attractive to replace the pneumatic cylinder 10 with a hydraulic cylinder because for a good cleaving action it is important that the inclined movement takes place as rapidly as possible; because of the small mass of the air it is apparent that a pneumatically driven cylinder has the advantage here. For the driving use is made of hydromotors. This is of course an attractive solution because a hydromotor has a small volume and can thus be incorporated easily at the relevant locations. It will be apparent that other types of drive means, such as electric motors, can also be employed. It can be attractive to increase the force on the knife driven in rotation with a weight fixed to the second lever 25. The above stated sequence is performed to prevent the nose from turning over. It is however possible within the scope of the invention to use another sequence.

Claims: Method for preparing a pig's head (6) for mechanical boning, characterized by making a transverse cut in the snout (33) from the underside of the head, wherein the cut separates the greater part of the rostral bone (34) (os rostrale) from the greater part of the jaw-bone (35) (os incisivum) to such an extent, that the rostral bone separated from the remaining skeleton forms a good gripping point for pulling loose the mask from the head. Method as claimed in claim 1, characterized in that a cut extending in lengthwise direction is made through the rind in the middle of the upper part of the head. Method as claimed in claim 1 or 2, characterized in that a cut is made in the snout (33) in lengthwise direction which extends into the nose bone (39) (os nasale). Method as claimed in claim 3, characterized in that the cut is first made in the rind and the transverse cut is then made in the snout. Apparatus for preparing, according to claim 1, a pig's head (6) for mechanical boning comprising: a support plate (4) for upside down placing thereon of the pig's head for preparing; and a cutting member (11) movable downward in inclining direction into the vicinity of the plate (4) and adapted for making a transverse cut in the snout from the underside of the head. Apparatus as claimed in claim 5, characterized by a saw-blade (26) which is driven in rotation and movable in a path extending in lengthwise direction of the head from the front of the snout into the snout, and which protrudes at least partially above the support plate. Apparatus as claimed in claim 5, characterized in that the cutting member (11) has a curved cutting face. Apparatus as claimed in claim 6, characterized by a knife-blade (17) which is driven in rotation and movable through a gap arranged in the support plate and which is adapted for at least cutting through the rind along the upper part of the head. Apparatus as claimed in claim 8, characterized in that the rotatably drivable knife-blade (17) is fixed to a first lever (16) which is connected via a second lever (15) to a pneumatic cylinder (19) for exerting an upward force on the cutting blade, and that the first lever is connected to a second pneumatic cylinder (21) for driving the knife-blade (17) in horizontal direction. Apparatus as claimed in claim 9, characterized in that the rotatably drivable saw-blade (26) is fixed to a third lever (25), which third lever is connected by means of a fourth lever (29) to the first lever. Apparatus as claimed in claim 10, characterized in that in the fourth lever the first lever is connected with play to the third lever.

Inventors: KETELS GERARDUS HUBERTUS JOHAN, KETELS, GERARDUS HUBERTUS JOHANNES
Applicants: STORK PROTECON LANGEN BV, STORK PROTECON-LANGEN B.V.
Application year: 1993
Main classification: A22B5
IPC codes: A22C17, A22B5