The present invention relates to a meat processing apparatus and methods of using that apparatus. The invention also relates to a sensing arrangement used in determining locations of bone and has particular application in automated frenching of lamb racks.

Background to the Invention

In meat processing, animal carcasses are processed to break the carcasses down into smaller cuts of meat for sale to consumers. In the case of processing lamb carcasses, one of the cuts of meat produced is known as a lamb rack. The lamb rack is made up of ribs, with a fillet of meat attached along the ribs. The rack undergoes a process known as "frenching" whereby intercostal fat and muscle is removed from between the exposed ends of the ribs.

The preparation of frenched lamb racks is a particularly labour intensive process. In a commercial operation where 3000 carcasses are processed in an eight hour shift, there may be 10 full time workers performing the frenching operation.

Currently there are two methods of carrying out the frenching operation:

manually using a knife, and to a lesser extent with the aid of a water blasting machine.

In the manual knife method, skilled operators french the racks by hand, using knives. Thus, skilled workers are required, and there is a risk of injury due to handling of knives, or repetitive strain injuries.

In the water blasting method, high pressure water jets are used to remove the intercostal meat. This method can be used by an operator with minimal training, but has drawbacks. For instance, the process uses significant quantities of water which is difficult to recycle as it is heavily loaded with meat and fat. Further, the water affects the appearance of the finished rack.

There remains a need to provide improved meat processing apparatus and methods.

Summary of the Invention

In a first aspect the present invention provides a sensor for determining the locations of bones in a meat processing operation including: a body; an array of elongate members are mounted in the body, the elongate members have distal and proximal ends and are moveable with respect to the body in a direction along their length from an extended position to a retracted position; the elongate members are biased to their extended positions.

The distal ends of the elongate members may include tissue piercing formations.

The elongate members may be biased to their extended positions by way of springs, each elongate member being associated with a spring.

When in their extended position, the proximal ends of the elongate members may be located inside the body, and when in the retracted position, the proximal ends may extend out of the body.

In a second aspect the present invention provides an apparatus for use in assessing where to make cuts in a meat processing operation including: a sensor according to the first aspect of the invention; and a visual detection means for detecting the positions of the elongate members.

The visual detection means may include a camera.

In a third aspect the present invention provides a method of assessing where to make cuts in a meat processing operation including the steps of: providing a sensor arrangement according to the first aspect of the invention; pressing the sensor against an item of meat of meat to be processed at a first location on the item with sufficient force such that the pins penetrate soft tissue areas of the item of meat; assessing the positions of the elongate members; and assessing where to make cuts based on the positions of the elongate members.

The method may further include the steps of: withdrawing the elongate members from the item of meat; moving the sensor with respect to the meat to a second location being offset from the first location; pressing the sensor against the meat for a second time; assessing the positions of the elongate members in the second locations; and wherein the step of assessing where to make cuts is further based on the locations of the elongate members in the second location.

In a fourth aspect the present invention provides a tool for use in a meat processing operation, the tool including: a first blade for cutting along the length of ribs; and a second double edged blade for cutting across between the ribs;

wherein the first and second blades are mounted on a common carrier, and are angularly displaced with respect to one another.

The first blade may be a single edged blade.

The second blade may be tapered.

The first and second blades may be offset by approximately 90 degrees.

Brief Description of the Drawings

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of an apparatus for use in assessing where to make cuts in a meat processing operation;

Figure 2 is a side view of the apparatus of figure 1 ;

Figure 3 is a cross sectional view of figure 2;

Figure 4 is a front perspective view of a sensor for determining the locations of bones in a meat processing operation;

Figure 5 is a rear perspective view of the sensor of figure 4;

Figure 6 is a side view of the sensor of figure 4;

Figure 7 is a front view of the sensor of figure 4;

Figure 8 is a cross sectional view along the line A-A of figure 7;

Figure 9 shows a lamb rack secured into the clamping mechanism of the apparatus of figure 1 ;

Figure 10 shows the output from the camera of the apparatus of figure 1;

Figure 11 shows the image of figure 10 following software manipulation;

Figure 12 shows a cutting arrangement used on a robotic arm; and

Figure 13 illustrates a cutting sequence made using the cutting arrangement of figure 12.

Detailed Description of the Preferred Embodiment

Referring to figure 1, an apparatus 10 is shown for use in assessing where to make cuts in a meat processing operation. In this embodiment, the apparatus is configured to carry out a frenching operation of lamb racks. The apparatus includes a shuttle 12, upon which is located a clamping mechanism 14. A lamb rack 16 may be releasably held in the clamping mechanism. The shuttle is moveable along a rail 18 by way of pneumatic ram 20 between two positions. In figure 1, the shuttle is shown in the sensing position. The shuttle can move to the right as seen in figure 1 to a cutting position as will be later described.

As best seen in figure 3, apparatus 10 includes a sensor 20 for determining the locations of bones. Now referring to figures 4 to 8, the sensor will now be described in detail. Sensor 20 includes a body being formed from front block 22, rear block 24, and plate 26. An array of elongate members in the form of pins 28 are mounted in bores 29 which extend from the front face to the rear face of the body. The pins are moveable in the bores from an extended position as shown in the figures to a retracted position. The pins 28 are biased to their extended position by way of springs 32, one of which is associated with each pin 28. The pins 28 may be moved to their retracted position by compression of springs 32. When in the retracted position, the proximal ends of pins 28 extend out the rear face of the rear block 24.

The distal ends of the pins 28 include tissue piercing formations in the form of sharpened points 30. The weight of springs 32 are selected so that, when the array of pins 28 is pressed against a piece of meat, the sharpened ends 30 of the pins penetrate soft tissue, such as muscle and fat, but do not penetrate bone.

Referring again to figure 3, apparatus 10 includes a visual detection means in the form of digital camera 40. An example of a suitable camera is a Cognex DVT535 camera with a 75mm Tamron lens. An infra red light source (not shown) is positioned within enclosure 42 in which the camera 40 is housed. Sensor 20 is mounted at the other end of enclosure 42 with the pointed ends of pins 28 facing downwards, and the rear face of the sensor facing camera 40. Apparatus 10 is movable in relation to shuttle 12 along with sensor 20 in an up and down direction for a distance equivalent to the maximum travel of pins 28.

The apparatus 10 is used to assess where to make cuts in the lamb rack as follows. A lamb rack 16 is secured in clamping arrangement 14 (see figure 9) and the shuttle 12 is brought to the sensing position underneath sensor 20 with the sensor in the up position. The sensor is then brought to the down position by way of a pneumatic ram (not shown) such that the sensor is pressed against the lamb rack 16. As the sensor moves downwards, the pins 28 strike the lamb rack 16. Where the pins meet soft tissue, they penetrate the lamb rack. Where pins meet bone, they do not penetrate the rack. Rather, the pins which strike bone are moved upwards in the sensor against the force of their respective compression springs 32 and the distal ends of these pins extend out of the rear face of rear block 24.

With the sensor in the down position, an image is captured from camera 40. As seen in figure 10, where the pins 28 that struck bone extend out of the block, these appear as bright regions. Where pins do not extend out of the block, the bores 29 are seen as dark regions. It can be seen from figure 10 that the bright regions correspond to regions of bone in the lamb rack.

The image from camera is processed by vision systems software, such as that known as DVT Intellect, to apply filters to emphasise the image and to estimate the locations of the bones in the rack. Cutting paths are then calculated based on the emphasised image. The sensor is raised away from the rack and the shuttle 12 moves along rail 18 to the cutting location where a robotic arm is situated, in this embodiment an XRC Motoman robot. The cutting path information is communicated to the robotic arm 50 which is fitted with a tool 70 which includes a cutting blade arrangement 60.

Referring to figure 12, the tool 70 includes a first blade in the form of a standard Swibo boning knife 72 which is sharpened along one edge only, and a second blade which is a specially made blade 74 which is tapered and sharpened along both edges. The first and second blades are angularly displaced by 90 degrees from one another. By rotating the wrist of the robot by 90 degrees, either the first or second blade are brought into use.

Referring to figure 13, robotic arm 50 removes intercostal meat by performing a cutting sequence as follows:

1. Blade 72 is inserted at point A and moved to point B to make a cut along the rib from A to B

2. Blade 72 is inserted at point C and moved to point D to make a cut along the rib from C to D.

3. Steps 1 and 2 are repeated for each section of intercostal meat along the rack.

4. Robot rotates tool 70 by 90 degrees to select blade 74.

5. Blade 74 is inserted into the rack at point E, being the mid-point between points A and C, to make a cut from A to C. The depth of insertion of blade 74 is controlled according to the taper of the blade so that the blade 74 effects a cut of the required length. The section of intercostals meat falls away.

6. Step 5 is repeated for each section of intercostals meat along the rack.

The result is a frenched lamb rack (see figure 13) which is removed from the clamping mechanism for subsequent packaging.

In an alternative method, the effective resolution of the pin array sensor 20 is increased by pressing the sensor 20 against the rack at two locations being slightly offset from one another. The camera 40 takes an image at both locations and both images are used to calculate averaged cutting paths. This effectively doubles the resolution of the pin array.

In some embodiments, the base of the clamping mechanism is provided with an array of bores that correspond to the bores 29 in the sensor. In this way, pins that pierce soft tissue pass through the rack and enter the bores in the base plate. This provides increased contrast between dark and light areas in the image taken by the camera.

Whilst the present invention has been described with reference to frenching of lamb racks, other embodiments of the invention may be optimised to process other cuts or other types of meat such as pork or beef.

It can be seen that embodiments of the invention have at least the following advantages: • Lamb racks can be processed in an automated manner, obviating the need for skilled operators.

• Risk of injury to operators is reduced.

• Meat is not affected by water jets.

Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.

Finally, it is to be appreciated that various alterations or additions may be made to the parts previously described without departing from the spirit or ambit of the present invention.