Method and device for boning meat portions

A method and device for boning meat portions, making use of two opposite pressing elements adapted to be moved to and from each other, wherein each pressing element comprising a recess provided with inserts, along the borderline of the recess each pressing element is provided with means to separate the meat material from the bone or bones, said separating means are following substantially the contour of the bones in the meat portion, for instance the front leg or shoulder portion of a pig, said recess in at least one of the pressing elements is provided with means for locking up or pressing the or each bone piece in length-wise direction thereof and at least one of the pressing elements is provided with gripper members for gripping at least one ridge of a bone; as a result the bone is held firmly in place in a well positioned manner during the meat extracting operation.

The invention relates to a method and device for boning meat portions, 
making use of two opposite pressing elements adapted to be moved to and 
from each other, wherein each pressing element comprising a recess 
provided with inserts. Along the borderline of the recess each pressing 
element is provided with means to separate the meat material from the bone 
or bones. Those separating means are following substantially the contour 
of the bones in the meat portion, for instance the front leg or shoulder 
portion of a pig. Such methods and device is for instance disclosed in 
applicants former application EU-A-0086020. 
The invention has for its object to ameliorate the method and device for 
separating the meat from the bones without the risk of damaging or 
breaking the bones. 
According to a first embodiment the invention is distinguished in that the 
recess in at least one of the pressing elements is provided with means for 
locking up or pressing the or each bone piece in length-wise direction 
thereof. In practice it turned out that the length of the bones in the 
meat portion to be pressed, is increasing, resulting in bone damage. Owing 
to the locking up means or press means, provided in the recess of the 
pressing elements, such variation in the length of the bone resulting bone 
damage is avoided. 
According to a further embodiment of the invention at least one of the 
pressing elements is provided with gripper members for gripping at least 
one ridge of a bone. As a result the bone is held firmly in place in a 
well positioned manner during the meat extracting operation. 
If the meat is removed from at least one cavity of the bone bounding the 
ridge by inserting one of the set of gripper members into the cavity, this 
gripper member is used for positioning and holding in place as well as for 
extracting meat. The meat present in the cavity is thus forced outward by 
the gripper member. A bone which is well positioned using the gripper 
members can easily be stripped of meat by being clamped between the 
gripper members on one side and a press element on the other. 
A simple, extremely well functioning device, preferably has clamping jaws, 
pivoting or sliding relative to each other. 
The set of gripper members is preferably forced by actuating means outside 
the pressing surface of a pressing element, whereby at least one stop 
member cooperating with a gripper member forces the gripper members away 
from each other. 
The invention will be further elucidated in the description following 
hereinafter with reference to a drawing of several embodiments according 
to the invention, with associated pieces of meat for boning.

The boning device in FIG. 1 comprises a frame 1 of such a rigid structure 
to withstand high pressing forces between the lower and upper pressing 
element 2 and 3 respectively. The pressing elements 2 and 3 are arranged 
opposite to each other whereas the upper element 3 is rigidly suspended to 
the top side of the frame 1, whereas the lower element 2 is supported by a 
hydraulic cylinder 4 arranged in the lower part of frame 1. Due to the 
cylinder 4, the piston of which is movable in up- and downward direction, 
the lower pressing element 2 can be moved upwardly starting from the 
position as shown in FIG. 1. 
Each element 3 is provided with a recess 5, which will be elucidated 
herebelow. The recess is adapted to receive the bone part in a meat 
portion M, which is to be deboned. 
It is assumed that the operator will put the meat portion M on top of the 
lower pressing element 2, whereupon after actuation of the hydraulic 
cylinder 4 the pressing element 2 is urged to pressing element 3, so 
punching out the bone part from the meat portion M. After having lowered 
the pressing element 2, the bone parts are left in the recess 5, whereas 
the meat portion can be removed from between the pressing elements. 
In order to have the bone part correctly placed near the recess 5, a 
plurality of members 6 are arranged in straddled relationship to the upper 
pressing element 3, said members urging the bone parts to the right 
position in between the lower and upper pressing elements 2 and 3. The 
working of said elements and the above mentioned device is disclosed in 
applicants earlier application as mentioned herebefore. It is noticed that 
in such a device the meat itself is not brought under pressure except for 
the bone part. 
Turning now to the FIGS. 2-6, it is noticed that the recess 5 in the lower 
and upper pressing element 2, 3 is provided with inserts 7 and 8 
respectively, of any suitable material. The pressing surface 9 of the 
inserts are cooperating such that the remaining space between the inserts 
when the lower and upper pressing element are pressed to each other will 
just receive the bone volume, such that all the meat material attached to 
the bone parts are urged outwardly. 
In order to avoid damage to the bone parts, that is to say, splintering or 
fracture of the bones, the inserts 7 in the lower pressing element 2 may 
yield downwardly into the lower recess 5 of said element, which is 
possible by reason of the particular support in the form of a piston 10. 
The lower end of the piston 10 is protruding in a pressing chamber 11, 
which can be filled with a hydraulic pressure fluid. The pressure is such 
that a sufficient pressure can be exerted upon the bone but not so high 
that the bone will damage. 
It is noticed that the inserts can be made of any suitable material such as 
flexible material, like rubber, but also metal, like copper etc. 
The insert 7"", right in FIG. 2, is not supported by a piston 10 as under 
the other inserts 7, but is supported without any yielding possibility in 
element 2. 
Said insert 7"" is nevertheless provided with a pair of gripping members 
12, 13 showing a head portion and a shank portion 14. The shank portion is 
strip-like and fits into a guiding orifice of a rectangular cross-section 
formed in the insert 7"". The head portions of the gripper elements 12, 13 
have a particular shape adapted to cooperate with one side of a bone 
portion, for instance a shoulder blade. Such a blade B is provided with a 
ridge 17 and adjacent cavities 15, 16, see also FIG. 4, 5. 
Furthermore the shank portions 14 of both the gripping elements 12, 13 are 
oblique to each other, so when lowering the shank portions in the inserts 
7"", the head portions will converge each other; and when moving upwards 
the head portions will diverge. 
In the embodiment shown in FIGS. 2-5, the gripping elements 12, 13 are 
supported by a piston 10' corresponding with the pistons 10 underneath the 
other inserts 7. 
As is clearly depicted in the FIGS. 4 and 5 the meat surrounding the 
shoulder blade B will be urged out of the cavities 15, 16 due to the 
profiled top surface of the head portions of gripping elements 12, 13, see 
FIG. 5. As soon as the meat is separated from the bone the pressing 
elements 2, 3 can be separated from each other to the position in FIG. 4, 
whereupon the piston 10' will urge the elements 12, 13 upwardly, so 
freeing the bone from the lower element. A next meat portion can be 
entered in between the lower and upper pressing element 2, 3 again, as is 
shown in FIG. 4. 
Turning to the FIGS. 7-11 several alternatives of the gripping elements 12, 
13 are elucidated. In the embodiment according to FIG. 7, 8 the upper 
press element 35 is suspended to hydraulic cylinder 36, whereas the lower 
pressing element is fixedly secured to a frame. Moreover the inserts are 
here embodied in rubber material 37. 
The embodiment of the device 23 as in FIG. 7, 8 comprises a press frame 24 
which has a lower press element 25. In press element 25 a clamp 26 is 
forced upward in vertical direction by a compression spring 10" instead of 
the hydraulic cylinder. Clamp 26 consists of a non-pivoting gripper member 
27 guided only in vertical direction in the press element 25 and a gripper 
member 28 which can pivot relative to gripper member 27 by means of a 
hinge 61. Gripper member 28 has a projection 29 which cooperates with a 
stop member 30 of press element 25. During upward movement of clamp 26 
gripper member 28 pivots in arrow direction 31 as a result of projection 
29 striking against stop member 30, this causing the clamp 26 to open. The 
position in FIG. 7, 8 is then reached. A piece of meat M can now be laid 
on press element 25, whereby the piece of meat M, in which a slight 
incision may or may not have been made beforehand, is placed with its 
ridge 17 into the opened clamp 26. The rest of the piece of meat M with 
the bone B shown therein is now placed into the recess 33 of the press 
element 25 adapted for the B. An upper press element 35 is then driven 
downward forcefully by means of hydraulic cylinder 36. Through deforming 
of the rubber 37 the bone B can be enclosed on all sides, so that 
virtually all the meat 39 with the exception of sinew is forced out of the 
press and is there cut off by means of a separating edge 20. It is noted 
that when the press is closed the clamp 26 is forced downward, as a result 
of which the gripper members 27 and 28 are forced towards each other, 
thereby clamping the ridge 9 tightly between them. Both gripper members 27 
and 28 thereby penetrate into the cavities 15 and 16 on either side of 
ridge 9, so that the meat present there is pressed out. There is then 
created, as it were, a continuous upper surface of the press element 25 
that is well adapted to the underside of bone B. 
With the device 41 in FIG. 9 a lower press element is formed by a frame 42 
having two gripper members 44 therein which can pivot in shafts 43, which 
members form, in lifted position by means of counterweights 45, an opened 
clamp in which can be placed a piece of meat M. During downward movement 
the gripper members 44 pivot downward and then penetrate into the cavities 
15 and 16 of bone B. The upper parts and edges of the gripper members 44 
are adapted to the underside of bone B. The downward forcing can be 
carried out by means of an upper press element (not shown). 
The device 51 from FIG. 10 and 11 is adapted for boning a piece of meat M 
with an end bone 54 that has a ridge 53. With this device 51 the piece of 
meat 52 is positioned on a press element 55 by means of a clamp 56 with a 
vertically guided, non-pivoting gripper member 57 and gripper member 57 
connected thereto for pivoting. 
In addition, a simpler clamp 59 may be employed for good positioning of the 
end bone 54 and thereby the entire piece of meat M. A press element (not 
shown) placed above this and adapted to the upper surface of the bone can 
be moved downward in order to press out all the meat. 
Turning now to FIG. 12 and 13, the embodiment here is also provided with 
particular inserts in the recess 60 of the lower pressing element 61 and 
upper element 62 respectively. Lower element 61 is movable in up- and 
downward direction according to arrow P1, what can be embodied by the 
cylinder 4 in FIG. 1. 
The inserts as shown are partly of solid material, like metal 63, an insert 
64 with gripping members 65 corresponding to the embodiment in FIG. 8, and 
yieldable material like rubber 66. The insert 63 in the lower pressing 
element 61 is supported by the pistons 10. 
As is clearly depicted in FIG. 13 the group of bones B are hingedly 
connected to each other, whereas the left portion in FIG. 13 is the 
so-called shoulder blade S. 
According to the invention the recess in both the pressing elements are 
provided with stop faces 74, which are formed here by the head end of a 
stub 75, protruding into the recess 60. 
Said stop face may also be a fixed part of the inner wall of the recess of 
the pressing element, see for instance at 74'. However the stop faces are 
located such there where the head ends K of a bone B is laying in the 
recess, whereby the bone is locked-up in length-wise direction. 
The middle-bone in FIG. 13 is solely supported at one side by a face 74, 
since due to its configuration the bone is supported in the hinge of the 
bone at the right side, so it will be locked-up sufficiently. 
Furthermore it will be noted that in the embodiment as shown in FIG. 12 and 
13 the upper pressing element is provided with such stop surfaces 74, 74', 
since the inserts 63 have such dimensions that in the closed position of 
the upper and lower pressing elements the bone will be received 
substantially in the upper pressing element. 
The advantage obtained by the stop faces 74, is that yielding inserts 63 
can be avoided easily, whereupon those inserts may be made in harder 
material, for instance stainless steel. Having an adapted contouring 
surface of the inserts, the bone will be enveloped rather accurate, and 
even when using high pressing forces the bone will be a bit deformed, but 
will not be damaged or fractured. Within the scope of the invention it is 
possible to provide the stub 75 with an actuating system 76, so being able 
to bring the stub 75 more or less far protruding in the recess and also 
the related stop face 74. It is also possible to urge a certain pressure 
upon the bone in length-wise direction by means of the system 76, so 
compensating even in high pressing forces of the pressing element 61, 62 a 
possible length variation of the bone. 
The actuating system 76 can be hydraulic, pneumatic or mechanic and it can 
fully be removed when the stub 75 has the form of a screw-bolt. When 
rotating the bolt is a threaded hole in the wall of the upper element, the 
face 74 can be brought more or less into the recess thereof. 
The reciprocating movement of the stub 75 can be effected before the meat 
portion M with including bones are laid upon the lower pressing element, 
but it can also be effected when the pressing elements are urged almost to 
each other, when a certain pressing force upon the bone piece is already 
available. In that case the hydraulic cilinder 76 can be actuated in order 
to bring the stub 75 and of course the stop face 14 against the head end 
of a bone in order to obtain the desired compensation force for 
diminishing the increase of length of the bone piece. 
In the next embodiment according to FIGS. 14 and 15 the stub 75 may have 
another position with respect to the element 62. FIG. 14 shows an orifice 
in the upper pressing element 62 to receiving a stub 75', which is more or 
less protruding into the recess of the pressing element by means of a 
corresponding actuating system 76'. The cylindrical surface of the stub 
75', here indicated with 74, serves as pressing surface which will contact 
the head end K of a bone B. The surface is inclined with respect to the 
direction of movement of the stub 75' in order to preload the bone piece 
more when the stub 75' is protruding more into the recess of the pressing 
element. 
FIG. 16 shows a exchangeable insert 77, the surface 74" of which facing the 
recess of the upper element 62 is also inclined, so when moving the 
pressing element against each other, the bone portion in the recess of the 
upper element 62 is preloaded in length-wise direction since the surface 
14" compresses the head end of the bone B. Owing to the inclination of the 
surface 74" it will happen that when urging the bone piece more in the 
upper element 62, the preloading upon the head end of the bone B will 
raise, what will diminish the increase of the length of the bone, so 
avoiding damage. 
The insert 77 is dependent upon the average bone form and is to be 
exchanged by other inserts, in order to obtain the optimum preloading upon 
the head end of the bone. This is dependent upon the experience and the 
skill of the operator. 
A fourth embodiment of a lock-up member for the head end of a bone piece is 
depicted in FIG. 17, wherein a ridge 78 is arranged in the insert 71, its 
knife-like edge protrudes from said insert. The location of the ridge 78 
is near the outer extremity of the insert 71 and so near the head end of a 
bone B. This knife-like ridge will carve into the bone when closing the 
pressing elements and in this manner a displacement of the head end is 
prevented and therefor the increase of the bone length. 
Also in this way there will be generated a force acting upon the bone, so 
preventing fracture of said bone. 
The invention is not limited to the embodiments as described hereabove and 
as shown in the drawings.