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

A method for preparing a pig's head for mechanical boning including making a transverse cut in the snout from the underside of the head so that the transverse cut separates the greater part of the rostral bone from the greater part of the jaw-bone, and apparatus for carrying out the method which includes a support structure for upside down placing thereon of the pig's head for preparing and cutting a member movable toward the support structure in direction inclining relative to the support structure and adapted for making a transverse cut in the snout from the underside of the head.

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 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 making a transverse cut in the snout from the 
underside of the head, wherein the cut separates the greater part of the 
rostral bone (os rostrale) from the greater part of the jaw bone (os 
incisivum). 
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. 
Another 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 
rostral bone improves the accessibility of the nasal cavity. 
According to the invention 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 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. 
It will likewise be apparent that diverse other modifications can be made 
to the device. 
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.