System and method for cleaning a carcass or carcass part of slaughtered poultry

The invention relates to a system for cleaning a carcass part of slaughtered poultry, which carcass part at least still comprises a part of the breast fillet and skin, which skin comprises at least a part of the breast skin, neck skin and skin in the region of transition between the breast skin and neck skin, wherein the breast skin and the skin in the region of transition between the breast skin and neck skin rest at least partly against the muscular tissue of the breast fillet, from which carcass part the muscular tissue of the neck and the neck vertebrae are substantially removed, which system comprises a neck skin removing device which comprises:

The invention relates to a system and method for cleaning a carcass or carcass part of slaughtered poultry.

The removing of skin from carcasses or carcass parts of slaughtered poultry is for example known from EP 0244887 which describes that the skin to be removed (in this case the breast skin) is first stretched. Afterwards, an incision is made in the stretched-tight skin, after which the skin is drawn loose from the underlying breast fillet by means of rolls which are provided with a profile.

The removed skin has a commercial value. However, the price paid therefor is highly dependent on the quality. The degree of soiling plays a part in this: the cleaner the breast skin, the higher the quality and thus the price.

Before the breast skin is removed, the carcass or carcass part has already undergone a number of processes. During one of said processes, the internal tissue of the neck (such as for example the muscular tissue, the neck vertebrae, a part of the windpipe and a part of the oesophagus) is removed at least for the most part. However, during this processing, a part of the neck skin in many cases remains connected to the carcass or carcass part, although “empty”. In practice, this still connected, substantially “empty” neck skin has in many cases been found to be more markedly soiled than the breast skin. The neck skin is relatively often soiled with for example crop remnants, bone remnants or blood.

During the harvesting of the breast skin, which usually does not take place until relatively late in the overall process of processing the slaughtered poultry, the connected neck skin often comes along with the harvested breast skin. However, the soiling of the neck skin leads to deterioration of the general quality of the harvested skin. For the buyers of the breast skin, such soiling of the harvested skin is more and more often unacceptable.

The object of the invention is to provide an improved system and an improved method for cleaning a carcass or carcass part of slaughtered poultry. A carcass or carcass part can for example be a front half, a breast cap or slaughtered and subsequently dressed poultry.

The object of the invention is achieved by the system according to claim1and the method according to claim27.

In the carcasses or carcass parts to be processed using the system and the method according to the invention, the breast skin which is present and at least a part of the skin in the region of transition between the breast skin and neck skin rest at least partly against the muscular tissue of the breast fillet. The internal tissue of the neck, in particular the muscular tissue and the neck vertebrae, is removed at least for the most part, so that the substantially empty neck skin hangs free from the remainder of the carcass or carcass part. The removal of the muscular tissue from the neck and the neck vertebrae takes place prior to the dressing of the slaughtered poultry, while the removal of the neck skin according to the invention takes place after the removal of the muscular tissue from the neck and the neck vertebrae, and preferably also after the dressing of the slaughtered poultry.

In an advantageous embodiment, the carcass or carcass part to be processed hangs from a product carrier with the neck side down, so that the empty, slack neck skin hangs freely downward. This can easily be achieved by product carriers which are arranged below an overhead conveyor path. In some cases, the empty neck skin will initially stick to a side or to the breast or back of the carcass or carcass part. Therefore, the system comprises in an advantageous embodiment a neck skin stretching device which engages the empty neck skin when that is stuck to the side edge of the carcass or carcass part, and subsequently brings the neck skin into a position hanging freely downward. The neck skin stretching device comprises for this purpose, for example, rolls or scrapers which loosen the neck skin by rubbing or scraping the carcass or carcass part.

A gripper engages the neck skin, after which in a stretching station a force, for example a tensile force, is exerted on the neck skin. This force tensions the skin, but the force which is exerted is not sufficient to tear the neck skin loose from the carcass or carcass part to be processed. The force which is exerted on the neck skin is so great that the skin of the region of transition between the neck skin and breast skin is stretched and is detached from the underlying muscular tissue.

During processing of a carcass or carcass part, the neck of which is directed downward, the neck skin can be pulled further downward, for example in the vertical direction. Preferably, the region of transition between the breast skin and neck skin is then pulled so far downward that it comes to lie lower than the muscular tissue of the breast fillet.

Subsequently, an incision is made in the skin of the region of transition between the breast skin and neck skin. This incision can pass right through the skin or cut into the skin in such a way that the neck skin is torn loose from the breast skin as a result of the tension which the tensile force causes in the breast skin. When the neck skin and the breast skin are separated from each other, the tensile force acting on the breast skin has of course disappeared.

Preferably, the skin tissue is pulled sufficiently far away from the muscular tissue of the breast fillet that the muscular tissue of the breast fillet remains out of reach of the blade with which the incision is made in the region of transition between the breast skin and neck skin.

As a result of the resilience of the skin tissue, the skin on the breast side of the incision made will to a significant degree return to the position which it assumed before a force was exerted thereon. The muscular tissue of the breast fillet is then again for the most part covered by the breast skin. If the incision is positioned correctly, no or almost no free-hanging skin tissue will remain. The process can be optimized partly by optimizing the amount of force exerted on the neck skin.

If the skin tissue is not tensioned in advance, this effect cannot be attained or can be attained only with great effort. The part of the skin that is, generally speaking, most soiled is thus removed from the carcass or carcass part. The skin which remains can accordingly be harvested separately from this soiled part, as a result of which it yields more money. Furthermore, the breast fillet, with just the skin resting against the muscular tissue, has a more attensile appearance, so that when it is sold as “skin-on breast meat”, it can be presented in a manner which the consumer will find more attensile. Also, no or less subsequent trimming of the skin is necessary in order to obtain a presentation which is attensile to the consumer.

A further advantage of the system and the method according to the invention is the fact that it offers the possibility of reducing the risk of damage to the breast fillet during the cutting-loose of the neck skin by the blade which cuts the neck skin loose. This results from the fact that in an advantageous embodiment the blade cuts through or cuts into the neck skin at a certain distance from the muscular tissue of the breast fillet. Otherwise, more soiled skin would remain connected to the carcass part, or the risk of damage to the breast fillet would be high.

The gripper can in principle be any construction which engages the neck skin. It is thus possible to embody the gripper in the form of gripper rolls which are provided with a profile. The profile engages with the neck skin. The rotation of the gripper rolls subsequently causes a tensile force to be exerted on the neck skin. The profile on the gripper rolls can have any suitable form, and thus be for example helical or straight and parallel to the longitudinal axis of the gripper rolls. In another embodiment, the gripper is embodied as a clamp with two jaw parts, between which the neck skin can be clamped. In still another embodiment, the gripper is embodied with one or more skewers which pierce the neck skin or project at least partly into the neck skin.

FIG. 1ashows a carcass or carcass part1of slaughtered poultry. In this example, the carcass or carcass part is a dressed carcass of slaughtered poultry, still with wings5, but the invention is also applicable to, for example, front halves and breast caps, with or without wings or parts of wings. The carcass or carcass part1comprises breast skin2, neck skin3and skin4in the region of transition between the neck skin and breast skin. The internal tissue of the neck, in the form of muscular tissue and neck vertebrae, is substantially removed before the method according to the invention is carried out. It may be the case that remnants of the muscular tissue or other tissue of the neck (such as parts of the oesophagus and/or windpipe) remain, but the neck skin is substantially “empty” and thus slack. Generally, the muscular tissue of the neck and the neck vertebrae will already be removed before dressing by a neck piece removing device. The cleaning of the carcass by removing the neck skin according to the invention preferably takes place after the dressing.

FIG. 1bshows the exerting of a tensile force F on the empty neck skin. As a result, the neck skin, the skin in the region of transition between the neck skin and breast skin and at least a part of the breast skin are stretched out. As a result of the tensile force, the skin4in the region of transition between the neck skin and breast skin becomes detached from the muscular tissue of the breast fillet. In this example, the part in question of the skin lies below the breast fillet (viewed in the vertical direction), as shown inFIG. 1b.

FIG. 1cshows an incision10which is made in the skin in the region of transition between the neck skin and breast skin. This incision10ensures that the breast skin is no longer subjected to the tensile force.

The incision is made by a blade which is moved toward the carcass part, or by a blade which is fixed next to the path along which the carcasses or carcass parts are moved. The relative movement of the carcasses or carcass parts along the path also ensures relative movement with respect to the blade; this can take care of or contribute to the making of the incision.

It is advantageous if the skin tissue in the region of transition between the breast skin and neck skin is pulled sufficiently far away from the breast fillet that the breast fillet remains out of reach of the blade. This prevents damage to the breast fillet and to the meat surrounding the breast fillet. As a result, the breast fillet remains intact and thus commercially valuable.

FIG. 1dshows the situation after the carrying-out of the method according to the invention. The breast skin has—partly as a result of its resilient properties—recoiled and covers most of the breast fillet. The edge11of the skin along which the incision10is made rests against the muscular tissue of the breast fillet. As a result of the fact that at the moment of cutting the skin which is cut through or cut into does not rest against the breast fillet, there is little risk of damage being caused to the breast fillet by the blade which cuts through or cuts into the skin.

The method according to the invention can be carried out automatically, that is to say, use is made of a system which carries out all the steps of the method or at least some of the steps of the method.

FIG. 2andFIG. 3show a first embodiment of a system according to the invention.FIG. 2is a side view,FIG. 3shows the system ofFIG. 2viewed counter to the direction of conveyance T. InFIG. 3, a part of the shaft21and drive22is omitted from the drawing for the sake of clarity.

In this example, the neck skin removing device of the system is provided with two gripper rolls15which are each provided with a helical profile16. The gripper rolls15are rotatable about their longitudinal axis; during operation, the gripper rolls15rotate counter to each other, as is shown by the arrows R inFIG. 3. Carcasses or carcass parts1are arranged in product carriers50. The product carriers are moved along a path in the direction of conveyance T.

When the free-hanging neck skin3of the carcass or carcass part1enters the region of the helical profiles16of the gripper rolls15, it is gripped by these profiles. The gripper rolls15rotate counter to each other and pull the neck skin3downward while the product carrier50, which carries the carcass or carcass part1in question, conveys this carcass or carcass part1onward in the direction of conveyance T. The gripper rolls15with the profiles16exert, as a result of their rotation, a tensile force F in the vertical direction on the neck skin3. Optionally, an additional tensile force can be generated in the horizontal direction by of the speed of conveyance of the product carrier50. As a result of the tensile force acting on the neck skin3, the skin4in the region of transition between the neck skin and breast skin and the breast skin2are also pulled downward or obliquely downward.

It has been found that the amount of tensile force which is exerted on the neck skin partly defines the results of the processing. It is therefore also advantageous if the tensile force which is exerted on the neck skin by the neck skin removing device is variable and/or adjustable. In the embodiment ofFIGS. 2 and 3, the tensile force from the gripper rolls15can be influenced by altering the distance between the profiles16of the gripper rolls15, for example by changing the centre-to-centre distance of the gripper rolls15. It is also possible to change the rigidity of the profile16of one or both gripper rolls15by means of the material selected for the profile16in question. In the event of a desired change of the tensile force, one or both gripper rolls are then exchanged in their entirety. Another possibility is for only the profile to be exchanged. This is possible if the profile16is made detachable from the associated gripper roll15, for example as a result of the gripper roll15being provided with a straight or helical slot into which a plastics material or rubber plate can be slid.

Furthermore, it is advantageous if also the direction of the tensile force acting on the neck skin can be adjusted. This can for example be achieved by way of the positioning of the grippers (gripper rolls or another design of the grippers) with respect to the path which the carcasses or carcass parts follow, and/or by creating a difference in speed between the carcasses or carcass parts along the path, on the one hand, and the speed which the grippers impose on the neck skin which they grip, on the other hand.

Preferably, the system is provided with guides17which ensure that the carcass or carcass part1is not pulled downward by the gripper rolls15. In this example, the guides17support the wings5. As a result of this support, which could in fact also engage an other part of the carcass or carcass part1, the tensile force F is effectively used for tugging on the neck skin3.

A rotating blade20is arranged downstream (viewed in the direction of conveyance T) of the gripper rolls15. The vertical distance of this blade20with respect to the product carriers50is selected in such a way that the blade20makes an incision10in the skin4in the region of transition between the neck skin and breast skin, which skin4is pulled downward with respect to the position which it naturally assumes as a result of the tensile force F which is exerted on the neck skin3. The blade20is attached to the shaft21and is driven by the drive22. The breast fillet of the carcass or carcass part1stays out of reach of the blade20.

Preferably, the vertical distance between the blade20and product carriers50is adjustable, thus allowing the location of the incision to be optimized.

The blade20makes an incision10, as a result of which the neck skin3is separated from the skin4out of the region of transition and from the breast skin2. In this example, the blade20cuts through the skin, although the tensile force F exerted by the gripper rollers15can make that the neck skin3is partly torn loose before the whole incision10is made.

FIG. 4andFIG. 5show a variant of the embodiment ofFIG. 2andFIG. 3. In the example ofFIG. 4andFIG. 5, the gripper rolls15are provided with a rectilinear profile18. The functioning of this variant is the same as the functioning of the embodiment shown inFIG. 2andFIG. 3.

FIG. 6andFIG. 7show the embodiment ofFIG. 2andFIG. 3, but now with front halves as carcasses or carcass parts1to be processed. The product carriers51used in the variant ofFIG. 6andFIG. 7are configured for the carrying of front halves, but can for example also hold breast caps.

FIG. 8andFIG. 9show the embodiment ofFIG. 4andFIG. 5, with the rectilinear profiles18on the gripper rolls15, but now with front halves as carcass parts1to be processed. The product carriers51used in the variant ofFIG. 8andFIG. 9are configured for the carrying of front halves, but can for example also hold breast caps.

FIG. 10shows a second embodiment of the system according to the invention. In the example ofFIG. 10, carcasses1are processed. The carcasses are dressed carcasses of slaughtered poultry that are carried by product carriers which engage on leg parts6of the carcass.

In the embodiment ofFIG. 10, the system according to the invention comprises a plurality of grippers30which each have two jaw parts30a,30b. The jaw parts30a,30bare hingeable with respect to each other so that the gripper30has an open and a closed position. In this example, a compression spring31is attached between the jaw parts30a,30bso that the gripper30is open when no force is exerted thereon any more. A person skilled in the art will understand that this can be achieved also in other ways, for example using weights.

In the embodiment ofFIG. 10, a plurality of grippers30are attached to an endless carrier, in this example an endless chain31. The pitch between successive grippers30is equal to the pitch between successive product carriers50. A person skilled in the art will understand that, instead of the endless chain31, an endless belt or cord can for example also be used. The chain is driven by motor32. When the motor32drives the chain31, the grippers30are moved along a path. During the movement along this path, the grippers30move synchronously with the product carriers50for at least part of the time, at the same speed and at the same pitch distance as the product carriers50. The system according toFIG. 10also comprises gripper guides33a,33b. The gripper guides ensure that the jaw parts30a,30bare brought from the open position to the closed position and are held for some time in the closed position when the grippers30pass the gripper guides33a,33b.

In use, a gripper30arrives, during the following of the path imposed by the chain31, at a given moment below a carcass or carcass part1to be processed, in such a way that the free-hanging part of the neck skin3comes to hang between the jaw parts30a,30b(situation as shown inFIG. 10, with regard to the carcass shown on the left-hand side). The gripper30moves at the same speed as the product carrier50which holds the carcass or carcass part1to be processed. As a result, the neck skin3hangs between the jaw parts30a,30b.

During the further movement, the gripper arrives between the gripper guides33a,33bwhich move the jaw parts30a,30btoward each other in order to close the gripper30, counter to the functioning of the compression spring31. When the gripper30is closed, it grips the free-hanging part of the neck skin3between the jaw parts30a,30b.

Although the path of the grippers runs in the same vertical plane as the product carriers50with the carcasses or carcass parts1, the vertical distance a between a gripper30and the product carrier50located thereabove gradually increases downstream. So, inFIG. 10, the distance a1is smaller than the distance a2. As a result of the fact that the vertical distance a between the gripper30and the product carrier50located above the gripper in question increases, the closed gripper30exerts a tensile force on the neck skin3. This is shown in the middle carcass inFIG. 10. The increasing of the distance a can be achieved by making the path of the grippers run downward with respect to the path of the product carriers, by making the path of the product carriers run upward with respect to the path of the grippers or by making both the path of the product carriers run upward and the path of the grippers run downward.

As a result of the tensile force acting on the neck skin3, the skin4in the region of transition between the neck skin and breast skin and the breast skin2are also pulled downward. Again, the guides17make that the carcass or carcass part1is supported and the tensile force is effectively used for displacing the skin4.

The system further comprises a rotating blade20. The vertical distance of this blade20with respect to the product carriers50is selected in such a way that the blade20makes an incision10in the skin4in the region of transition between the neck skin and breast skin, which skin4is pulled downward with respect to the position which it naturally assumes as a result of the tensile force which is exerted by the grippers30on the neck skin3. The blade20is attached to the shaft21and is driven by the drive22. The breast fillet of the carcass or carcass part1remains out of reach of the blade20.

Preferably, the vertical distance between the blade20and product carriers50is adjustable, thus allowing the location of the incision to be optimized.

The blade20makes an incision10, as a result of which the neck skin3is separated from the skin4out of the region of transition and from the breast skin2. In this example, the blade20cuts through the skin, although the tensile force exerted by the gripper30can cause the neck skin3to be partly torn loose before the whole incision10is made.

Once the neck skin3has been cut loose from the remainder of the carcass or carcass part1, the gripper30passes the return roll34. The gripper30leaves the region of the gripper guides33a,33b, as a result of which the compression spring31hinges the jaw parts30a,30bapart so the gripper30opens.

FIG. 11shows a variant of the embodiment according toFIG. 10. In the variant ofFIG. 11, the system is used with front halves as carcass parts1to be processed. The product carriers51used in the variant ofFIG. 11are configured for the carrying of front halves, but can also for example hold breast caps. The functioning of the variant ofFIG. 11is furthermore similar to the functioning of the embodiment ofFIG. 10.

FIG. 12shows a further variant of the embodiment ofFIG. 11. In this variant, use is made of the possibility of swivelling the product carrier51about the axis52in order to increase the distance between the product carrier51and gripper30. This manner of increasing the aforementioned distance can be used as an alternative to or in addition to the possibilities indicated in relation toFIG. 10for increasing the distance between a gripper and the product carrier located above this gripper.

FIG. 13shows a further variant of the embodiment ofFIG. 10. In the embodiment ofFIG. 13, grippers30are used, which are provided with a toothed plate35having sharp points36. These sharp points36secure the neck skin3.FIG. 13shows this variant in combination with product carriers50which engage the leg parts6of the carcasses or carcass parts1. It will be clear to a person skilled in the art that this variant can also be used for the processing of front halves or breast caps, wherein use is for example made of the product carriers51which have already been shown and are suitable for holding front halves or breast caps. The functioning of the variant ofFIG. 13is furthermore similar to the functioning of the embodiment ofFIG. 10.

FIG. 14shows a variant on the embodiment ofFIG. 13. In the variant ofFIG. 14, grippers37are used, which are each provided with a single sharp point38. The sharp point38grips the neck skin3.FIG. 14shows this variant in combination with product carriers50which engage the leg parts6of the carcasses or carcass parts1. It will be clear to a person skilled in the art that this variant can also be used for the processing of front halves or breast caps, wherein use is for example made of the product carriers51which have already been shown and are suitable for holding front halves or breast caps. The functioning of the variant ofFIG. 14is furthermore similar to the functioning of the embodiment ofFIG. 13.

FIG. 15shows a variant of the embodiments ofFIG. 2andFIG. 6. In the variant ofFIG. 15, a static blade40having cutting edges41a,41bis used instead of the rotating blade20on the shaft21, which rotating blade20is driven by the drive22. Preferably, the cutting edges41a,41btogether form a V shape, so that the neck skin3cannot easily pass the static blade40without being cut into or cut through. The functioning of the variant ofFIG. 15is furthermore similar to the functioning of the embodiments ofFIG. 2andFIG. 6.

FIG. 16shows a variant of the embodiments ofFIG. 4andFIG. 8. In the variant ofFIG. 16, a static blade40having cutting edges41a,41bis used instead of the rotating blade20on the shaft21, which rotating blade20is driven by the drive22. Preferably, the cutting edges41a,41btogether form a V shape, so that the neck skin3cannot easily pass the static blade40without being cut into or cut through. The functioning of the variant ofFIG. 16is furthermore similar to the functioning of the embodiments ofFIG. 4andFIG. 8.

It will be clear to a person skilled in the art that also in the other embodiments shown, a static blade40can be used instead of a rotating blade20.

FIG. 17shows a further variant of the embodiment ofFIG. 10. In this embodiment, the method according to the invention is carried out in a carousel machine instead of in a machine with a line layout. The closing of the gripper30and the downward movement of the gripper30with respect to the carcass or carcass part1to be processed are activated in this variant by cam tracks45a,45bwith cam rolls46a,46b. As is shown inFIG. 17aandFIG. 17b, use may be made of a static blade40which is arranged at a fixed position (so this blade does not rotate in tandem with the carousel). As an alternative, asFIG. 17cshows, use may also be made of a rotating blade20. The rotating blade20is then also arranged at a fixed position, and thus does not rotate with the carousel.

In this variant, the moving parts of the grippers30are protected by screens47. The screens contribute to the safety of persons who are located in proximity to the machine.

In a further variant, which is shown inFIG. 18, a force is exerted on the neck skin which is positioned at an angle (greater than 0°) to the direction of the breastbone of the carcass or carcass part to be processed.

In a further embodiment, which is shown inFIG. 19, the force is exerted on the neck skin by a guide which pulls the neck skin to the side. The distance between the gripper and product carrier can then remain constant, although that is not necessary.

It will be clear to a person skilled in the art that also in the variants ofFIGS. 18 and 19, the breast fillet remains out of reach of the blade.

FIG. 20shows the anatomy of the neck of a chicken. Various parts may be distinguished therein. Parts A and D (including part F, which is a component of part D) together form the regio colli ventralis. A is in this case the anterior part, D the posterior part. The caudal boundary of the posterior part D of the regio colli ventralis is roughly V-shaped and follows substantially the course of the Pectoralis superficialis muscles over the wishbone (claviculum). The posterior part D also comprises a region F, the crop region.

The neck region further comprises the regio colli lateralis which is denoted inFIG. 20by the letter C. A region of this type is located on both sides of the neck.

The regio colli dorsalis is located on the side of the back. The regio colli dorsalis is denoted inFIG. 20by the letters B, E and H. The letter B denotes in this case the dorsum anterius colli, the letter E the dorsum posterius colli and the letter H the regio interscapularis. The regio interscapularis H is the part between the shoulder blades. The shoulder region itself is denoted inFIG. 20by the letter G.

The borders of the various aforementioned regions, as indicated inFIG. 20, are merely indicative.

Dashed line10denotes globally the position of an incision which can be formed in an advantageous embodiment of the method and system according to the invention. In this case, the initially still present parts of the skin of the regio colli ventralis A, D (including at least a part of the skin in the crop region F), the regio colli lateralis C, the dorsum anterius colli B and the dorsum posterius colli E are cut loose from the carcass part. The skin in the regio interscapularis H remains wholly or at least for the most part on the carcass part.

In an advantageous variant, all the skin is removed from the crop region.

In other species of poultry which are used on a large scale for human consumption, the anatomy of the neck region has in many cases broadly the same appearance.

Various embodiments and variants of the system according to the invention have been described hereinbefore. It will be clear to a person skilled in the art that these embodiments and variants, and also separate aspects thereof, may be combined with one another.