| 1. | A method of separating at least part of the spinal column from an animal carcase, the method comprising locating the blade of a band saw around the spinal column; and moving the band saw along the length of the spinal column while cutting thereby separating at least part of the spinal column from the carcase without cutting the spinal column. |
| 2. | A method according to claim 1, wherein a Ushaped cut is made from the ventral aspect. |
| 3. | A method according to claim 1 or claim 2, wherein the cutting process is made from the sacral or the thoracic ends of the carcase. |
| 4. | A method according to any of the preceding claims, wherein the carcase is one of cattle, pig, sheep, goat, and deer. |
| 5. | A band saw comprising an endless band mounted for cyclic movement along a closed path to a support, the endless band having a depending blade, and the support being constructed such that part of material being cut can pass through a region defined within the path of the blade. |
| 6. | A band saw according to claim 5, the support including two movable members positioned in contact so as to define a nip through which the endless band passes and wherein at least one of the movable members is coupled to a driving means. |
| 7. | A band saw according to claim 6, wherein one of the movable members is an endless belt and the other movable member is a roller, the endless belt extending around part of the roller with the endless band sandwiched between them. |
| 8. | A band saw according to any of claims 5 to 7 , the support including an idler roller and two subsidiary rollers, each subsidiary roller being positioned in contact with the idler roller to define respective nips through which the endless band passes. |
| 9. | A band saw according to any of claims 5 to 8 , wherein the said region is defined by a parabolicshaped section of the blade's path. |
| 10. | A band saw according to any of claims 5 to 9, wherein the support includes an elongate guide member having a slot for the blade. |
| 11. | A band saw according to any of claims 5 to 10, wherein the blade includes a number of serrations. |
| 12. | A band saw according to claim 11, wherein the blade has two sets of serrations, each set extending laterally outwardly in respective different directions so as to cut a slot wider than the guide member. |
| 13. | A band saw according to any of claims 5 to 12 , further comprising a depth control member which abuts against the material being cut to control the depth of penetration of the band saw blade(s) into the material. |
| 14. | A method according to any of claims 1 to 4 , wherein the band saw is constructed according to any of claims 5 to 13. |
The invention relates to a method of separating at least part of the spinal column from an animal carcase and to a band saw for that purpose.
The spinal cord of any animal is considered to be a source of contamination and in the case of cattle the spinal cord is now classified as Specified Bovine Offal requiring special handling and disposal procedures. The current slaughterhouse practice is to cut or split the carcase into two halves using a manual or automatic cleaver, or a band, reciprocating or circular saw. The blade passes through the centre line of the carcase and cuts into the spinal cord often causing cord material to be smeared over the cut surfaces and smaller particles to be released into the atmosphere.
The spinal canal, which carries the spinal cord is situated at varying distances from the dorsal mid-line. The minimum distance is in the order of 50mm (in the sacral region) , the maximum in the order of 300mm (in the cranial thoracic region) . This variation, and particularly the depth of cut required in the thoracic region introduce considerable practical difficulties into a system which attempts to remove the cord by cutting from the dorsal aspect of the carcase. The cord is situated at a more or less constant centre line depth of 60mm from the ventral bodies of the vertebrae and is thus more accessible using a constant depth of cut.
In accordance with one aspect of the present invention, a method of separating at least part of the spinal column from an animal carcase comprises locating the blade of a band saw around the spinal column; and moving the band saw along the length of the spinal column while cutting thereby separating at least part of the spinal column from the carcase without cutting the spinal column.
The present invention removes a section of the spinal column without cutting into or breaking the spinal column
allowing the carcase to be split conventionally or manually back finned, which ever is more suitable depending on the size of the carcase. This minimises and usually eliminates the risk of carcase contamination while allowing expensive cuts of meat, for example sirloin, to be removed without damage.
Preferably, a cut is made from the ventral aspect as this allows removal of the spinal cord encased in a portion of each vertebrae. Whilst the cut may be of any shape, such as a U-shape, preferably the cut is parabolic-shaped as the band saw functions more reliably with the band having a parabolic as opposed to a U-shape.
Following removal of the spinal cord, the resulting carcase can be cut in half and butchered as normal. Since, in some methods, the animal's head is left in place until further down the slaughter line, preferably the cutting process is made from the sacral or the thoracic ends of the carcase.
The carcase can be cattle, pig, sheep, goat, deer or other suitable animal. The present invention is applicable to a wide range of species, but in general the description will be limited to the example of cattle. This should not be taken as limiting the applicability of the invention in any way. In accordance with a second aspect of the present invention, a band saw comprises an endless band mounted for cyclic movement along a closed path to a support, the endless band having a depending blade, and the support being constructed such that part of material being cut can pass through a region defined within the path of the blade.
Preferably the support includes two movable members positioned in contact so as to define a nip through which the endless band passes and wherein at least one of the movable members is coupled to a driving means. Typically one of the movable members is an endless belt and the other movable member is a roller, the endless belt extending around part of the roller with the endless band sandwiched
between them. This allows positive slip free drive of the endless band without having to rely on band tension although any suitable arrangement which allows the endless band to be driven, could be used. Typically the support also includes an idler roller and two subsidiary rollers, each subsidiary roller being positioned in contact with the idler roller to define respective nips through which the endless band passes. This helps direct the endless band toward the guide member whilst urging the band into the required parabolic shape.
This particular form of band saw is well suited for use in methods according to the first aspect of the invention where the spinal column can pass through the region defined within the path of the blade. Thus, this region is typically defined by a parabolic-shaped section of the blade's path.
Preferably, the support includes an elongate guide member having a stepped guide for the blade, although the stepped guide may be replaced by a slot for the blade. Typically, the blade includes a number of serrations and in a particularly preferred arrangement, the blade has two sets of serrations, each set extending laterally outwardly in respective different directions so as to cut a slot wider than the guide member. In order to control the position of the band saw while cutting, preferably the saw further comprises a depth control member which abuts against the material being cut to control the depth of penetration of the band saw blade into the material. This depth control member is typically in the form of a skid plate.
An example of a method and a band saw according to the invention will now be described with reference to the accompanying drawings, in which:-
Figure 1 is a perspective view of the band saw; Figure 2 is a partial side elevation with parts cut away of the band saw shown in Figure 1;
Figure 3 is an enlarged section on the line 3-3 in Figure 1; and,
Figure 4 is an underneath plan view of the main band saw components in use. The band saw shown in the drawings comprises a drive motor 1 which may be powered by compressed air, hydraulics or electricity depending on the services available. The motor 1 is mounted to a band support 2 having a handle 2a and a drive gear housing 3. An endless, metallic band 5 is mounted to the housing 2 and projects beyond the end of the housing as shown in Figure 1 around a parabolic-shaped path along which it is guided by a correspondingly parabolic- shaped guide member 6 having a depending stepped guide 7 (Figure 3) . A skid plate 4 is mounted to the underside of the housing 2 to form a depth control guide to ensure that the band saw is kept at the correct position within the spinal column.
As can be seen more clearly in Figure 2, the depending side of the endless band 5 is formed with cutting serrations 8. The serrations 8 are formed in two sets, one set 8A extending generally in a first lateral direction and the other set 8B extending in the opposite lateral direction as seen in Figure 3. The ends of the serrations 8A,8B terminate laterally outwardly of the dimensions of the guide 6 so that in use a slot is cut through which the guide can pass.
As shown in Figure 4, the endless band 5 is entrained around a drive roller 13, which is coupled to the motor 1, and an idler roller 14. There are also provided two subsidiary rollers 15 which are used to maintain contact between the idler roller 14 and the endless band 5. This also helps to ensure that the endless band 5 maintains a parabolic shape around the guide 6. The rollers are all mounted to the support 2. In order to ensure that the endless band 5 engages the drive roller 13, there iε provided a rubber pressure belt 16 which is entrained about a second drive roller 17, a
guide roller 18 and a tension roller 19 mounted to the support 2. The drive roller 17 is driven by the motor 1 via gears 30,31 such that the surface of the rubber pressure belt 16 moves with a speed equal to the surface speed of the drive roller 13. The rubber pressure belt 16 maintains close contact between the endless band 5 and the drive roller 13 to ensure positive slip free drive of the endless band 5 resulting in cyclic motion of the endless band. In use, the parabolic-shaped projecting section of the band saw is threaded around the spinal column 12 of the carcase (Figure 4) and the band saw activated so that the band 5 is rotated around the rollers 13,14 and commences a cutting action. The skid plate 4 ensures that the band is correctly located about the spinal column. The operator then moves the band saw along the spinal column, the spinal column passing through the guide 6 as shown in Figure 4 so that it can be removed. It will be noted in particular that the spinal cord is neither cut nor damaged in this operation.
Use of the device introduces another operation into the dressing specification located after evisceration. If the head is removed the operator stands on a rise and fall platform and starts at the thoracic end. By positioning the device on the severed end of the spinal column and cutting upwards the core of the spinal column is removed as the operator moves up the carcase. At the sacral end the device can be angled to cut it's way out of the bone and the resulting spinal core can be dropped into an SBO bin. If the head has to be left in place the operator starts at the sacral end and uses the device to cut into the bone just below the tail. The operator now runs the device down the carcase towards the head and stops at the head. The device is then withdrawn over the cut column and the tail end is hooked onto an additional roller located between the back legs. The neck is now butchered manually to produce a cut column with the head attached.