DEVICE FOR BONING MEAT

Abstract: In a press for boming meat two press elements (1,3,6,7) are movable towards each other to press meat (19) from bones (20) positioned therebetween. At least one of the press elements (6,7) is in two parts, the pressing part proper (7) and a part (6) surrounding part (7) and carrying a cutting edge (9). The pressing part proper (7) is movable with respect to the surrounding part (6) and rests therein on the liquid in a liquid-filled space (11) between these parts (6,7), closed by a compressible sealing ring (10) and in communication with a valve (13), operated so that it is closed during pressing to have the pressure in the liquid in said space (11) transmit the pressing force. At the end of pressing the valve is opened so that the pressing part proper (7) relatively moves somewhat backwards with respect to the surrounding part (6) and exerts less force. The pressing force is now concentrated on the surrounding part and thus on the cutting edge (9) to sever bone membrane, sinews and the like to separate the meat fully from the bone.

Description: The invention relates to a device for boning meat, as given in the preamble of claim 1. Such a device is known from European Patent Application Nr. 0 086 020 (Fig. 10). It shows a cutting edge which lies around the press area and at the end of the pressing boning operation is pressed onto a counterface of the other press element in order to separate the meat pressed away from between the pressure faces fully from the bone still between them, wherever bone membrane, sinews and the like still connect the meat to the bone. The first part here rests on a supporting surface in the second part, which supporting surface is movable in the direction of pressing with respect to the second part and rests on a diaphragm outside the second part, which diaphragm encloses a gas space, closed to the outside to form a gas spring. This allows the first part to be pushed deeper into the second part during pressing, to allow the cutting edge to become fully active at the end of the pressing operation. A disadvantage of such devices is that at the end of the pressing operation the press pressure has to distribute itself over pressure faces and cutting edge, so that the pressure on the cutting edge cannot be high unless the total pressure force is greatly increased, which greatly increases the mechanical forces and thus the strains on the system and necessitates a heavier design of press and of the drive. When the first part moves deeper into the second part towards the end of the pressing operation, the gas in the gas space is compressed, so that the pressure exerted by the first part on meat and bones increases. Moreover, this means that the press pressure on the bones left behind between the pressure faces risks being greatly increased, so that there is a risk of those bones being crushed too much. Besides, it is difficult in such a device to prevent the cutting edge from starting to cut too soon, i.e. before the meat is pressed sufficiently away from between the pressure faces. The object of the invention is then to find a solution to this, combining simplicity of design and operation with efficient carrying out of a high cutting pressure at the end of the boning operation. For this purpose, a device of the type referred to in the preamble is characterized by the characterizing part of claim 1. The liquid used can be water. When the valve is closed, during pressing the press pressure will be passed on by the liquid through the then shut-off space to the part within the cutting edge, and this will cause a corresponding pressure to arise in said space without any appreciable change in volume. When the valve is open the liquid can leave said space, which means that the pressure force is not passed on (or with some counterpressure for the liquid at the outflow side of the valve only to a slight degree) to said part situated within the cutting edge, and the pressure force is thus all or virtually all used to exert pressure between cutting edge and counterface. During said cutting the valve can be open or can be closed again immediately after the outflow of any liquid, in order to maintain a desired, now lower pressure force on the bones, so that no meat returns to the bone before it is properly severed. At the next press stroke it must then, of course, be ensured that the space is filled completely with liquid again. This can be carried out simply by maintaining a slight liquid pressure at the outflow side of the valve to fill the liquid space again if no pressing is taking place, thus if there is hardly any pressure in said liquid space. It is easy and advantageous to design the device in such a way that when the liquid space is filled and shut off for pressing the pressure faces within the cutting edge in the direction of pressing lie closer together than the cutting edge and its counterface. The meat can then come away freely during the pressing, without being impeded by cutting edge and counterface, while during cutting the liquid space is so much shorter in the direction of pressing due to discharged liquid that the cutting edge can easily go against the counterface, unimpeded by the pressure faces now projecting less or not projecting at all. The filling and emptying of the liquid space can be controlled in a simple manner, for example with sensors which observe the closing of the press (the pressure faces going on top of one another) and operate it with a delay device in a signal line to the valve. After cutting, the press can be opened, and this opening movement or a certain open position of the pressing elements ensure that the liquid space is filled again for the next pressing. The invention will now be explained in greater detail with reference to the appended drawings, showing the parts of a boning device which are important for the invention, in a preferred embodiment, leaving out other drive parts etc. for which you may refer to known designs such as according to the above-mentioned European Patent 70,605. In the drawings; Fig. 1 shows a vertical section through said device in the open position; Fig. 2 shows a vertical section of the lower die only, along a plane at right angles to the plane of Fig. 1; Fig. 3 shows the same section as Fig. 1, during boning by pressing; and Fig. 4 shows the same section during cutting after pressing. A press has an upper die 1 and a lower die 2 which can be moved vertically towards each other for pressing. A hollow of upper die 1 contains a press element 3 of hard elastic material such as polyurethane with a recess 4 to accommodate a bone, as known from the above-mentioned European patent. The face part 5 of the steel upper die around said press element serves as the counterface for a cutting edge, and to this end can be provided with an extremely hard, for example welded-on layer, for example of carbide. The lower die 2 has an element 6 which in a hollow accommodates a press element 7 with a recess 8 for bone, complementary to recess 4 in element 3 of the upper die. The element 6 has at the top a cutting edge 9 totally enclosing the press element 7. The press element is accommodated in the element 6 so that it is adapted to slide vertically with little play in element 6 and rests on a soft rubber (or plastic) ring 10 surrounding a liquid space 11 between the bottom of element 7 and the bottom of the hollow in element 6. The ring follows the periphery of the recess in element 6 and is thus in this case essentially rectangular with rounded corners. This space is connected by a line 12 to a valve 13 (Fig. 2), which can allow the liquid through in throttling fashion to and from a liquid tank 14 with overflow 15 and filling line 16. The valve 13 is motor-driven, under the influence of a signal line 17, which leads from sensors (not shown) for establishing the closing of the press via a time delay 18 to the valve. A piece of meat is indicated by 19 and a bone in it by 20. This device then works as follows: Either the upper die 1 or the lower die 2 can be fixed, and the other one is then movable vertically. When the press dies are moved apart vertically (position in Fig. 1) a piece of meat 19 with bone 20, which is to be boned in the press, is placed on element 7 of the bottom press die 2 with the bone as exactly as possible directly above the recess 8 for it. The liquid space 11 is filled to the maximum with liquid such as water, and the valve 13 is closed. The element 7 herewith extends above the cutting edge 9, for example along a vertical distance of approx. 5 mm. The press is now closed by moving the movable die vertically towards the stationary one. The piece of meat 19 becomes jammed between the hard elastic press elements 3 and 7 and, on further closing, the meat is pressed out sideways between said elements 3 and 7. The increasing downward reaction force which is undergone by the press element 7 in the process puts the liquid confined in space 11 under pressure but, since the volume thereof cannot change, the press element 7 remains projecting above the cutting edge 9. This continues until the relative position of the parts shown in Fig. 3 is reached. The meat 19 then projects on all sides beyond the elements 3 and 7 pressed onto each other, the bone is confined in the hollows 4 and 8, and the meat is still joined to the bone by bone membrane, sinews and the like. The cutting edge 9 is still free from face part 5 of top die 1, as shown in the drawing. Approach sensors now establish that the press elements 3 and 7 have come onto each other to an adequate extent, and a signal is thereby passed via line 17 to valve 13, but with some delay in device 18, for example 2 secs., in order to make sure that the meat has been pressed out adequately. This delayed signal now opens valve 13 very slowly, so that the pressure in space 11 falls gradually. The liquid flows through valve 13 to tank 14, in which a constant liquid level is maintained through overflow 15 and filling line 16, so that the liquid pressure in space 11 cannot fall further than to this level. In the meantime the press dies 1 and 2 are moved further towards each other, causing cutting edge 9 to move towards and up against face part 5. During that movement press element 7 is stopped by press element 3 and compresses sealing ring 10, so that it becomes thinner in the direction of pressing and wider at right angles thereto (Fig. 4). The liquid space 11 becomes smaller and excess liquid is pressed out easily through the still open valve 13. It is now possible at a desired moment, i.e. at a desired volume of space 11, to close the valve 13, but this is not always necessary at this stage. The total pressure force by the press elements now acts to a much lesser extent on the press elements 3 and 7 and acts largely between cutting edge 9 and counterface part 5, so that the cutting edge 9 presses with great force thereon and cuts off all parts still connecting the meat to the bone. The meat cut off now falls downwards along the slanting sides of element 6 of the lower die and is easily removed. The press is now opened by moving the press elements 1 and 2 apart vertically to the position shown in Fig. 1. The valve 13 is opened or is kept open, through lack of press reaction force the liquid pressure in space 11 is lower than the pressure at the bottom of tank 14, and the space 11 fills up again with liquid until the situation of Figs. 1 and 3 is obtained. The natural shape of the circular sealing element 10 can help here, because it is selected in such a way that it corresponds to that height of space 11. The press element 7 is thus raised again relative to the cutting edge until it is in said position of Figs. 1 - 3. The valve 13 is now closed and a new press cycle begins. In addition to the influence of signal line 17, other signal lines can act on the valve 13 to make it produce these described movements automatically, for example the closing can be controlled by sensors which establish that the press is open far enough, or that the press element 7 is projecting far enough above the cutting edge when the press is open.

Claims: 1. Device for boning meat, comprising a press with two press elements (1, 2), one of which can move towards the other to press the meat with bones between their pressure faces in order to detach the meat from the bones and release it sideways from between the pressure faces, with a cutting edge (9) for cutting away the meat (19) from the bone (20) left behind between the pressure faces at the end of the pressing operation, in which the cutting edge (9) is fitted on one of the press elements (1, 2) and cuts by being pressed towards and against a counterface (5) on the opposite press element, and in which at least one of the press elements (2) is in two parts, having in the pressing zone inside of the cutting edge (9) a first part (7) for contacting and pressing the meat to be boned, said first part (7) being accommodated in a second part (6) which extends around the first part and forms the cutting edge (9) or the counterface (5) thereof, said first part (7) situated within the cutting edge (9) being supported at its surface opposite the contacting and pressing surface by a fluid in a closed space (11) located opposite the contacting and pressing surface, characterized in that the space is filled with liquid and located between said opposite surface of the first part and the bottom of a recess in said second part, in that said first part (7) is supported via the liquid by the bottom of the recess in said second part (6) which is adapted to accomodate the first part (7) therein, said space being connected to a valve (13), which when closed shuts off the liquid in said space (11) so that during pressing said liquid is brought under pressure, and which when open gives said liquid the chance to leave said space (11) to the extent that the pressure in said space is lowered, so that on further movement of the press elements towards each other with open valve (13) the press load is transmitted essentially totally to the second part (6) alone, the dimensions of the first and second parts (7, 6) and of said liquid-filled space (11) in the direction of pressing being such that with closed valve (13) during pressing the first part (7) first acts against pressure surface of the other press element (1) without contact of cutting edge (9) and counterface (5), and that, with open valve (13), the first part (7) is moved deeper into the second part (6) to cause contact of cutting edge (9) and counterface (5). 2. Device according to Claim 1, in which the said first part (7) engages in the second part ( 6 ) in a sliding fit in the direction of pressing, and a peripheral elastically deformable sealing element (10) is located between the said opposite surface of the first part and the bottom of the recess and defines and shuts off the liquid space (11) along the edge thereof between them, said sealing element (10) being capable of becoming shorter in one direction and simultaneously thicker in the direction perpendicular thereto. 3. Device according to Claim 2, in which said first part (7) rests with its bottom directly on the liquid space (11) and on the sealing element (10). 4. Device according to any of the preceding claims, with approximately vertical direction of pressing, in which the liquid space (11) is disposed in the bottom press element (1, 6). 5. Device according to any of the preceding claims, in which when the liquid space (11) is filled and shut off for pressing the pressure faces within the cutting edge (9) in the direction of pressing lie closer together than the cutting edge (9) and its counterface (5). 6. Device according to any of the preceding claims, in which sensors observe the closing of the press for boning, and a time delay device (18) is fitted in a signal line (17) to the valve (13) to open the liquid space (11) at the end of the boning operation to initiate the cutting operation.

Inventors: KETELS, GERARDUS HUBERTUS JOHANNES
Applicants: STORK PROTECON B.V.
Application year: 1988
Main classification: A22C17
IPC codes: A22C17