Abstract:
The invention provides a combination of a conveying device for slaughter animals and a removing device ( 15 ). The conveying device comprises a guide ( 2 ) extending along a transport path, product carriers ( 3 ) for the slaughter animals, which are movable in a direction of movement along the guide, each product carrier comprising at least one groove inclined according to a direction of inclination for holding at least one held part of a slaughter animal therein. The at least one groove has an open upper end and a lower end. The removing device comprises a pusher element, which is movable to and fro between a passive position and an active position for pushing the at least one held part out of the at least one groove. The removing device comprises a further pusher element which is movable to and fro between a further passive position and a further active position. The pusher element is designed to push the at least one held part of a slaughter animal from the intermediate position, via the upper end of the at least one groove, out of said at least one groove in the active position or during its movement from the passive position to the active position.

Description:
The present invention relates to a combination of a conveying device for conveying slaughter animals suspended from product carriers of the conveying device, during which conveyance the slaughter animals describe a path, and a removing device disposed along said path for removing selected slaughter animals from the product carriers, the conveying device comprising a guide extending along a transport path, product carriers for the slaughter animals, which are movable in a direction of movement along the guide, each product carrier comprising at least one groove inclined according to a direction of inclination for holding at least one held part of a slaughter animal therein, wherein the at least one groove has an open upper end and a lower end and is laterally oriented relative to the conveying device, at least at the location of the removing device, the removing device comprising a pusher element, moving means for moving the pusher element to and fro between a passive position, in which the pusher element is located outside the path of slaughter animals, and an active position, in which the pusher element is located in the path of at least one held part of a selected slaughter animal in the active position, or at least during movement from the passive position to the active position, for pushing the at least one held part of the selected slaughter animal out of the at least one groove of a product carrier via the upper open end of said at least one groove. 
     BACKGROUND OF THE INVENTION 
     In slaughterhouses, where slaughter animals suspended from product carriers of a conveying device are processed, there is a continuous pursuit of increasing the capacity. Modern slaughter lines for slaughter birds are capable of processing typically at least 12,000 birds per hour, for example, but even higher capacities are considered to be desirable with a view to reducing the cost involved in the processing of slaughter birds. Various possibilities, whether or not in combination with each other, are available for increasing the capacity of a slaughterhouse. A first possibility is to increase the speed of the conveying device by means of which the slaughter animals are conveyed through a slaughterhouse, during which conveyance the slaughter animals are processed. A second possibility is to reduce the pitch between successive product carriers. In slaughterhouses it may for several reasons be necessary to selectively remove slaughter animals, such as birds, from a product carrier at the location of a processing position. The term “selective” indicates that only selected slaughter animals are to be removed from the product carrier at the location of the processing position, whilst for example the slaughter animals in an adjacent upstream product carrier and an adjacent downstream product carrier must not be removed from said product carrier at the location of said processing position. Such a selection may for example take place on the basis of the weight of the slaughter animal or on the basis of a visual assessment of a slaughter animal. A transfer situation may occur, in which a slaughter animal is transferred from one product carrier to another product carrier. Alternatively, specific slaughter animals may fall from a product carrier into a collecting bin or onto a further conveyor, such as a belt conveyor. 
     When relatively high speeds of the conveying device are used, there is an increased risk that the at least one held part of slaughter animals will slip out of the at least one groove of a product carrier, in particular in bends in the conveying line. For that reason it may be desirable to use a relatively large angle between a horizontal line and the direction of inclination, being the direction in which the at least one groove extends, and/or to use a relatively long groove. Alternatively, or in combination, it is also conceivable to dimension and/or configure the grooves to have a slight local constriction of the width of the grooves, so that the held parts, such as typically a bird&#39;s legs in the case of birds, are held in the lower end of a groove with a slight clamping fit and/or a more or less form-locked fit. 
     All the above possible aspects connected with increasing the capacity of a slaughterhouse in themselves make it more difficult to selectively remove slaughter animals from a product carrier. On the one hand this is the case because the use of product carriers that may have been adapted in the above-described manner with a view to realising higher line speeds makes it more difficult to remove slaughter animals from the product carriers, whilst on the other hand higher line speeds and or smaller pitches increase the risk that a pusher element by means of which a slaughter animal is removed from a product carrier, more specifically by means of which the at least one held part of a slaughter animal is pushed out of at least one slot of a product carrier, will undesirably collide with a slaughter animal suspended from an adjacent upstream or downstream product carrier. Accelerating the stroke of the pusher element will increase the impulse that acts on the at least one held part of the slaughter animal, so that there is an increased risk of damage to the slaughter animal and of undesirable bone fractures. 
     European publication EP 1 922 935 A1 describes a combination according to the introduction, wherein the moving means comprise a stepping motor or a servomotor and wherein it is possible to impart a movement or speed pattern to the pusher element, which is claimed to make the combination more suitable for high-speed operation. Apart from the fact that this is a relatively costly solution, the magnitude of the positive effect that may be achieved is moreover limited. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the invention is to provide a solution or at least an improvement as regards such problems. In order to achieve that object, the invention provides a combination as described in the introduction, wherein the removing device comprises a further pusher element as well as further moving means for moving the further pusher element to and fro between a further passive position, in which the further pusher element is located outside the path of slaughter animals, and a further active position, in which the further pusher element is located in the path of the at least one held part of the selected slaughter animal in said further active position, or at least during its movement from the further passive position to the further active position, for pushing the at least one held part of the selected slaughter animal from the lower end, in the direction of the upper end, to an intermediate position, wherein the pusher element is designed to push the at least one held part of a slaughter animal from the intermediate position, via the upper end of the at least one groove of a product carrier, out of said at least one groove in the active position or during its movement from the passive position to the active position. 
     The use of a further pusher element, in combination with a pusher element that is known per se, creates the possibility that initially the at least one held part is pushed from the lower end of the at least one slot in the direction of, but not as far as, the upper end of the at least one slot, after which the pusher element will push the at least one held part from the position of the at least one held part in the at least one slot effected by the further pusher element past the upper end of the at least one slot, and thus out of the at least one slot. The advantage of using a further pusher element may be that the pusher element will need less force for pushing the at least one held part of a slaughter animal, such as a bird&#39;s legs, past the upper end of the at least one slot, so that there will be a decreased risk of damage to the slaughter animal. The advantage of using a further pusher element may also be that as soon as the further pusher element has pushed the at least one held part of the slaughter animal out of the lower end of the at least one slot, and a first part of the movement of the at least one held part that is needed for removing the slaughter animal from the product carrier has thus been carried out, and preferably as soon as the pusher element subsequently comes into contact with the at least one held part or at least with one held part in the case of two or more held parts, the further pusher element can be moved back to the further passive position. The risk of a slaughter animal in an adjacent upstream product carrier undesirably coming into contact with the further pusher element can thus be considerably reduced, in spite of the fact that the pusher element is still engaged in pushing the at least one held part of the slaughter animal out of the at least one slot, and in spite of the fact that a relatively high line speed and/or a small pitch between the product carriers is/are used. On the other hand, the pusher element need not move from the passive position to the active position until the further pusher element has been moved to the active position. This, too, reduces the risk of a slaughter animal in an adjacent downstream product carrier undesirably coming into contact with the pusher element. 
     An embodiment of the invention that is advantageous for reasons of constructional simplicity is obtained if the pusher element is pivotable about a pivot axis between the passive position and the active position. 
     In an advantageous embodiment, such a pivot axis may extend parallel to the direction of movement. In such a variant, pushing the legs of a slaughter animal of the slots of the product carrier in lateral direction relative to the conveying direction can take place in that the pusher element exerts an impact load on the at least one held part. The movement of the at least one held part in the direction of the open end of the at least one slot is thus obtained during movement of the pusher element from the passive position to the active position. 
     Alternatively it may also be advantageous within the scope of the invention if the pivot axis extends at least substantially perpendicular to the direction of movement. In such a configuration it is more logical if the movement of the at least one held part in the direction of the open end of the at least one slot is obtained whilst the pusher element is in the passive position. The pusher element will in that case function as a guide element, which urges the at least one held part of the slaughter animal sideways in the direction of and past the open end of the at least one slot. 
     If the pivot axis moreover extends perpendicular to, at least substantially so, the direction of inclination, it will be easy to effect a situation in which the pusher element moves closely past the bottom side of the at least one slot, for example at a distance of at most 5 cm, or even more preferably at most 2 cm, upon pivoting between the passive position and the active position. This is advantageous with a view to reducing moments that act on the at least one held part when the slaughter animal is pushed sideways by the pusher element. 
     If the pivot axis is provided on an upstream side of the pusher element, the additional advantage will be that the risk of a next slaughter animal undesirably colliding with the pusher element is further reduced and/or that the magnitude of the pivot angle between the passive position and the active position can be relatively small. 
     The invention can in particular, but not exclusively, be used advantageously if the direction of inclination includes an angle that ranges between 40 degrees and 50 degrees with a horizontal line. The at least one groove will in that case extend at a relatively steep angle, as a result of which the product carriers in question can be suitable for being operated at a relatively high line speed, for example of 18,000 slaughter animals per hour. 
     The further pusher element may be pivotable about a further pivot axis between the further passive position and the further active position, which may be advantageous also for reasons of constructional simplicity. 
     As was the case with regard to the pivot axis as described above, it may also be advantageous for the further pivot axis if the further pivot axis extends at least substantially perpendicular to the conveying direction and furthermore preferably at least substantially perpendicular to the direction of inclination. 
     From the viewpoint of the preparatory function of the further pusher element with a view to moving held parts of slaughter animals entirely out of the slots it may be advantageous if the further pusher element, in the further passive position thereof, is located at least partially upstream of the pusher element in the passive position thereof. 
     If, according to a possible embodiment, the pusher element, at least in the active position thereof, and/or the further pusher element, in the further active position thereof, is/are designed for laterally guiding the at least one held part of a selected slaughter animal in the direction of the open end of the at least one groove of a product carrier during transport of the slaughter animal in the direction of movement, to which end the pusher element and/or the further pusher element comprise a guide surface and/or a further guide surface, respectively, wherein, seen in top plan view, the guide surface and/or the further guide surface include(s) an acute angle with the conveying direction in the active position and/or the further active position, respectively, it is possible to obtain the advantage that the mechanical load exerted on the slaughter animal, more specifically on the at least one held part thereof, upon removal of the slaughter animal from the product carrier will be limited. The additional advantage is moreover the fact that contact between the pusher element or the further pusher element and a non-selected slaughter animal suspended from a next (upstream) product carrier need not directly result in damage to the slaughter animal in question. 
     An effective removal of a slaughter animal from a product carrier can be obtained in particular if the pusher element, in the active position thereof, and the further pusher element, in the further active position thereof, are designed for laterally guiding the at least one held part of a selected slaughter animal, wherein the angle which the guide surface includes with the conveying direction is larger than the angle which the further guide surface includes with the conveying direction. In such an embodiment, the speed at which a slaughter animal is pushed sideways by the further pusher element will initially be lower than at a later stage, when the slaughter animal is pushed sideways by the pusher element. Said larger angle has the advantage that the legs are pushed out of the slots more quickly, and thus within a relatively shorter conveying length, by the pusher element in comparison with the further pusher element, which need not be problematic if the configuration of the slots makes it possible that the legs are moved through the slots by the pusher element with less resistance than the resistance that the legs experience upon being moved through the slots by the further pusher element. The reason for this may be that the slots diverge in the direction of the upper ends and/or that only the lower ends of the legs are held in the slots with a slight clamping fit or in a more or less form-locked manner. 
     An advantageous embodiment of the invention can likewise be obtained if the pusher element comprises a guide surface as well as a connecting surface that joins the guide surface on the upstream side of the guide surface, which connecting surface, seen in top plan view in the active position of the pusher element, includes an angle with the conveying direction which is larger than the angle which the guide surface includes with the conveying direction. Thus, the situation in which the guide surface of the pusher element joins the further guide surface of the further pusher element for taking over the guiding function can be realised more quickly during pivoting of the pusher element to the active position. 
     The invention is quite suitable, but not exclusively so, for use in transferring slaughter animals from one product carrier to another product carrier, which will usually be of a different type. In that case the slaughter line will comprise further product carriers which are movable along a further conveying path, which further product carriers are designed for taking over the slaughter animals whose at least one held part is being pushed out of the at least one groove by the pusher element via the upper end of the at least one groove of a product carrier. 
     The invention is also quite suitable, but not exclusively so, for use with slaughter animals having at least two legs, such as in particular slaughter birds. For the processing of such slaughter birds it is preferable that each product carrier comprises two grooves. In said two grooves, the legs, being the held parts of the slaughter words, can be received. 
     The slaughter line according to the invention can be used advantageously in particular if the moving means and the further moving means are designed to carry out the following steps for the purpose of pushing the at least one held part of a slaughter animal out of the at least one groove
     A moving the further pusher element from the further passive position to the further active position for pushing the at least one held part of a slaughter animal from the lower end of the at least one groove in the direction of the upper end of the at least one groove to an intermediate position during step A or because of step A,   B moving the pusher element from the passive position to the active position after step A for pushing the at least one held part of slaughter animal from the intermediate position, via the upper end of the at least one groove of a product carrier, out of said at least one groove during step B or because of step B,   C moving the further pusher element from the further active position back to the further passive position after step B,   D moving the pusher element from the active position back to the passive position after step B.
 
The moving means and the further moving means may to that end comprise a control unit, such as a PLC control unit, for example, but a purely mechanical solution, for example using a cam disc, is also conceivable. Using the further pusher element and the pusher element, a two-stage approach is obtained, as it were, for moving the at least one held part of a slaughter animal out of the at least one slot from the lower end to the upper end. The invention makes it possible for the further pusher element to have returned to the further passive position, thus providing space for a next slaughter animal, while the pusher element is still in the active position and is operative for completely pushing the at least one held part of a slaughter animal out of the at least one slot of a product carrier, making it possible to use relatively high line speeds or a relatively small pitch between adjacent product carriers.
   

     The invention further provides a method for operating a combination of a conveying device and a removing device according to the invention as described in the foregoing. The method comprises the steps of
     A moving the further pusher element from the further passive position to the further active position for pushing the at least one held part of a slaughter animal from the lower end of the at least one groove in the direction of the upper end of the at least one groove to an intermediate position during step A or because of step A,   B moving the pusher element from the passive position to the active position after step A for pushing the at least one held part of slaughter animal from the intermediate position, via the upper end of the at least one groove of a product carrier, out of said at least one groove during step B or because of step B,   C moving the further pusher element from the further active position back to the further passive position after step B,   D moving the pusher element from the active position back to the passive position after step B.   

     It is possible to carry out step D after step C, which can be an advantage is in particular if both the further pusher element and the pusher element function as guide means for pushing a bird&#39;s legs laterally out of the slots. 
     In particular in the case of the above possibility it may be advantageous if the length of the time interval between steps A and C and/or the length of the time interval between steps B and D is at most 80%, more preferably at most 75%, of the length of the time interval between steps A and D. Qualitatively it could be said that the more the above percentage decreases, the greater the advantages of the invention as regards the possibilities of operating conveying devices at higher speeds and/or width smaller pitches between the product carriers will be. 
     Alternatively it is also quite possible, however, for step B to be carried out simultaneously with or even (shortly) before step C. This can be an advantageous possibility if the pusher element pushes the at least one held part out of the at least one slot with a bump upon moving from the passive position to the active position. 
     An advantage use of the invention can be obtained if a slaughter animal is taken over from a product carrier by a further product carrier during step B or between steps B and D. 
     In general the invention can be used in the processing of slaughter animals, but it is in any case quite suitable for use with slaughter birds. 
     The invention further provides a removing device for use in a slaughter line according to the invention as described in the foregoing. Such a removing device comprises a pusher element, moving means for moving the pusher element to and fro between a passive position, in which the pusher element is located outside the path of slaughter animals, and an active position, in which the pusher element is located in the path of at least one held part of a selected slaughter animal in the active position, or at least during movement from the passive position to the active position, for pushing the at least one held part of the selected slaughter animal out of the at least one groove of a product carrier via the upper open end of said at least one groove, wherein the removing device comprises a further pusher element as well as further moving means for moving the further pusher element to and fro between a further passive position, in which the further pusher element is located outside the path of slaughter animals, and a further active position, wherein the further pusher element is located in the path of the at least one held part of the selected slaughter animal in said further active position, or at least during its movement from the further passive position to the further active position, for pushing the at least one held part of the selected slaughter animal from the lower end, in the direction of the upper end, to an intermediate position, wherein the pusher element is designed to push the at least one held part of a slaughter animal from the intermediate position, via the upper end of the at least one groove of a product carrier, out of said at least one groove in the active position or during its movement from the passive position to the active position. 
     The invention will be explained in more detail hereinafter by means of a description of non-limitative possible embodiments of the present invention, in which reference is made to the following figures: 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         FIG. 1  shows a detail relevant to the invention of a slaughter line according to the invention, including the associated removing device according to the invention; 
         FIGS. 2 a -2 d    show in top plan view four successive stages of the ejection of a bird from a product carrier by means of the removing device; 
         FIG. 3  is a view along the line III-Ill in  FIG. 2   d;    
         FIG. 4  shows the removing device from a different perspective; 
         FIG. 5  is a view of the removing device as shown in the preceding figures, used in a transfer station; 
         FIG. 6  shows a part of a slaughter line according to a second embodiment of the invention, including the associated removing device; 
         FIGS. 7 a -7 c    show in top plan view three successive stages of the ejection of a bird from a product carrier by means of the removing device; 
         FIG. 8  shows the removing device of  FIG. 6 , used in a transfer station; 
         FIG. 9  shows a time-displacement diagram associated with  FIGS. 2 a   - 2   d;    
         FIG. 10  shows a time-displacement diagram associated with  FIGS. 7 a   - 7   c.    
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a part of a slaughter line  1  which is provided with a guide rail  2  extending along a transport path. The slaughter line  1  further comprises product carriers  3  provided at regular intervals, which product carriers are interconnected via a conveyor chain  4 . Each product carrier  3  is provided with a guide part  4  on the upper side and with a hook part  5  thereunder. The guide parts  4  are provided with running wheels  6 , on which the product carriers  3  can roll in the direction of movement  24  along the guide rail  2  when the conveyor chain  4  is being driven. The pitch between adjacent product carriers  3  is 8 inches, or in other words, about 200 mm. Also other dimensions, such as 6 inches (152 mm), 8 inches) 203 mm), 10 inches (254 mm) or 12 inches (305 mm) are quite conceivable. 
     The hook part  5  has an at least substantially hooked J-shape (see also  FIG. 3 ) and has a widened slot part  7  at the bottom end, in which two identically shaped slots  8  (see also  FIGS. 2 a -2 d   ) are provided. The slots  8  each have a length I. The slot part  7  has a direction of inclination  9  ( FIG. 3 ) that includes an angle α of 45° with a horizontal line that extends perpendicular to the direction of movement  24 . The slots  8  each have a laterally facing open upper end  11  and a closed lower end  12 . The slots  8  taper off slightly from the upper end  11  to the lower end  12  and have a constant width over a certain part of the length of the slots  8  at the lower end  12 . Said width is adapted to the dimensions of bird legs, so that said legs can be accommodated in the lower end  12  with a slight clamping fit, such that the tarsal joint will remain above the lower end  12  of the slots. 
     The slaughter line  1  further comprises a removing device  15 , which is rigidly suspended from the guide rail  2  via a support construction  16 . The removing device  15  comprises a table body  17 , which is rigidly connected, via an upright part  18 , to the vertical part of the support construction  16 , and which further comprises a tabletop  19 . The tabletop  19  extends parallel to the direction of inclination  9  of the slot parts  7  that form part of hook parts  5  of passing product carriers  3 . To selectively remove birds  13  from a passing product carrier  3 , more specifically to push the legs of a bird  13  out of the slots  8  of an associated product carrier  3 , as will be explained in more detail yet with reference to  FIGS. 2 a -2 d   , the removing device  15  comprises a first, upstream pusher arm  21  and a second, downstream pusher arm  22 . 
     The first pusher arm  21  is connected to the tabletop  19  such that it can pivot to and fro, between a passive position and an active position, about a pivot axis  23  that extends perpendicular to the tabletop  19 . In the passive position of the first pusher arm  21 , as shown in  FIGS. 2 a  and 2 d   , the first pusher arm  21  extends outside the path of birds  13  suspended from passing product carriers  3 , more or less parallel to the conveying direction  24 , on the downstream side of the pivot axis  23 . In the active position shown in  FIGS. 2 b  and 2 c   , the first pusher arm  21 , or at least part thereof, is located in the path of passing birds  13 , more specifically in the path of the legs  14  thereof. In the active position, the first pusher arm  21  extends at an angle of about 23 degrees relative to the conveying direction  24 , seen in a direction perpendicular to a plane parallel to the table  19 , or in other words, parallel to the slot part  7 . In the active position, the end of the first pusher arm  21  is located approximately halfway the length of the slots  8 , seen in top plan view. Exactly at that location, the slots  8  widen in the direction of the upper open ends  11 . 
     The second pusher arm  22  is likewise connected to the tabletop  19  such that it can pivot to and fro between a passive position and an active position about a pivot axis  25 , which likewise extends perpendicular to the tabletop  19 . In the passive position of the second pusher arm  22 , as shown in  FIGS. 2 a  and 2 d   , the second pusher arm  22  extends outside the path of birds  13  suspended from passing product carriers  3 , more or less parallel to the conveying direction  24 , on the downstream side of the pivot axis  25 . In the active position shown in  FIGS. 2 b  and 2 c   , the second pusher arm  22 , or at least part thereof, is located in the path of passing birds  13 , more specifically in the path of the legs  14  thereof. In the active position, the second pusher arm  22  extends at an angle of about 33 degrees relative to the conveying direction  24 , seen in a direction perpendicular to a plane parallel to the table  19 , or in other words, parallel to the slot part  7 . In the active position, the end of the second pusher arm  22  is located near the upper ends  11  of the slots  8 , seen in top plan view, upon passage of the associated product carriers  3 . 
     The pusher arms  21  and  22  are located under the tabletop  19  and are connected to an end of a connecting arm  33 ,  34  via respective shaft members  31 ,  32  which extend through the tabletop  19 , being pivotally journalled therein. The central axes of the shaft members  31 ,  32  coincide with the respective pivot axes  23 ,  25 . At the opposite end, the connecting arms  33 ,  34  are connected to the ends of piston rods  35 ,  36  associated with pneumatic cylinders  37 ,  38  which are connected to the tabletop  19  such that they can pivot to and fro about pivot axes  39 ,  40 . Suitable actuation of the cylinders  37 ,  38 , which can be individually controlled by means of a control unit (not shown), causes the associated pusher elements  21 ,  22  to pivot between the associated active and passive positions. The first pusher arm  21  is to a limited extent located closer to the tabletop  19  than the second pusher arm  22 , so that there may be some overlap between the two pusher arms  21  and  22 , as is shown in  FIG. 2 a    and in particular in  FIG. 2   d.    
     Now the selective removal of a bird  13 ′ from a product carrier  3 , using the removing device  15 , will be described. 
     The starting situation is the situation shown in  FIG. 2 a   . The control system of the slaughter line  1  delivers a command to the control unit of the removing device  15  that an approaching bird  13 ′ is to be removed from the associated product carrier  3 . To that end the first pusher arm  21  is made to pivot from the passive position to the active position thereof ( FIG. 2 b   ) by suitable actuation of the cylinder  37  as soon as the adjacent downstream bird  13  offers space for such pivoting of the first pusher arm  21 . The result of the pivoting of the first pusher arm  21  is that the first pusher arm  21  comes to lie in the path of the legs  14  of the bird  13 ′, and because of the previously described inclined orientation of the first pusher arm  21  relative to the conveying direction  24 , the legs  14  of the bird  13 ′ are pushed sideways one after the other from the closed lower ends  12  of the associated slots  8  in the direction of the upper ends  11 . The legs remain suspended in the slots  8 , however. 
     Subsequently, as shown in  FIG. 2 c   , also the second pusher arm  22  will be pivoted from the passive position to the active position thereof as soon as the downstream bird  13  offers space for this, which is before the bird  13 ′ has fully passed the first pusher arm  21 . The second pusher arm  22  is so positioned relative to the first pusher arm  21  that in the respective active positions thereof the end of the first pusher arm  21  joins the second pusher arm  22 , as shown in  FIG. 2 c   . As a result of pivoting to the active position, the second pusher arm  22  will also come to lie in the path of the legs  14  and take over the guiding function for the legs of the bird  13 ′ from the first pusher arm and push the legs  14  further in the direction of the open ends  11  of the slots  8  until the legs  14  come clear of the slots  8 . Because the angle that the second pusher arm  22  takes up relative to the conveying direction  24  in the active position is larger than the corresponding angle of the first pusher arm  21 , the legs  14  are more quickly guided in lateral direction by the second pusher arm  22  than by the first pusher arm  21 . This reduces the cycle time. The inclination of the first pusher arm  21  in the active position is limited on account of mass inertia effects and the possible need to overcome also friction forces that act between the legs  14  and the tapered slots  8 . If the legs  14  are guided in lateral direction too quickly by the first pusher arm  21 , the risk of damage to the legs  14  will be greater. 
     The above process is also shown in the diagram of  FIG. 9 , in which the vertical axis shows the lateral movement (i.e. in horizontal direction perpendicular to the direction of movement  24 ) of (the ends of) the first and the second pusher arm  21 ,  22  and also of the legs  14  of a bird  13 ′. As regards the value y indicated on the vertical axis, y−I×cos(α) applies. Typically, the interval between the forward movement of the first pusher arm  21  and the return movement of the second pusher arm  22  could be 275 ms. 
     Once the upstream leg  14  of the bird  13 ′ has fully passed the first pusher arm  21 , the first pusher arm  21  will pivot back again from the active position to the passive position as shown in  FIG. 2 d   . In this way the upstream bird  13 , which, as determined by the central control system, is not to be removed from the associated product carrier  3  by the removing device  15  in this example, is prevented from coming into contact with the first pusher arm  21 . 
     Once the upstream leg  14  of the bird  13 ′ has fully passed the second pusher arm  22  as well, the second pusher arm  22  will also pivot back to the passive position, so that the upstream bird  13 ′″ will not impeded by the second push arm  22 , either. The starting situation shown in  FIG. 2 a    is then reached again. 
     Incidentally, in the situation in which a bird  13  in the adjacent upstream product carrier  3  must be removed from said product carrier  3  as well, the pusher arms  21 ,  22  need not pivot back to their respective passive positions. Said pivoting back will only happen in a situation in which a bird  13  in an adjacent upstream product carrier  3  need not be removed from said product carrier  3 . 
     Once a bird  13  has been removed from a product carrier  3  by the removing device  15 , the bird can fall into a collecting bin, for example, under the influence of the force of gravity. Alternatively it is also possible to use the removing device  15  with a so-called transfer device as shown in  FIG. 5 . In slaughterhouses it may desirable for various reasons to transfer a bird  13  from one product carrier to another product carrier, usually of a different type, possibly from a product carrier of a transfer station, such as the one indicated at  40  in  FIG. 5 . The product carrier  40  forms part of an transfer station  45  as described in detail in European publication EP 1 848 282 B1. Like the product carrier  3 , the product carrier  40  has two slots  41 , which are spaced the same distance apart as the slots  8  of a product carrier  3 . The product carrier  40  forms part of a carousel, to which product carrier a parallel, synchronised movement with the product carrier  3  is imparted at the location of the removing device  15 , during which movement slots  41  of the product carrier  40  and slots  8  of the product carrier  3  are temporarily aligned. Using the pusher arms  21 ,  22 , a bird is pushed from the product carrier  3  into the product carrier  40  in a manner already explained in the foregoing. It is conceivable in that regard for the hook parts  5  to be slightly tilted about a tilt axis that extends parallel to the conveying direction  24 , so that the associated slot parts will have a flatter orientation, making it easier to remove birds  13  from the product carriers  3 . 
       FIG. 6  relates to a second embodiment of the present invention. Insofar as elements of the second embodiment correspond to elements of the first embodiment shown in  FIGS. 1-5 , corresponding reference numerals will be used. 
       FIGS. 6-8  show a slaughter line  101 , or at least a part thereof that is relevant to the invention. The slaughter line  101  comprises a removing device  115 . The removing device  115  comprises a pusher arm  121  which can be made to pivot to and fro between a passive position ( FIG. 6 ,  FIG. 7 a    in dotted line) and an active position ( FIGS. 7 a -7 c   ) about a pivot axis  123  by suitable actuation of the cylinder  137 . 
     The removing device  115  further comprises a pusher arm  122  which will be indicated hereinafter by the term “ejector arm”  122 . The ejector arm  122  can be made to pivot to and fro between a passive position ( FIGS. 6, 7   a ,  7   b ) and an active position ( FIG. 7 c   ) about a pivot axis  125  that extends parallel to the conveying direction  24  by suitable actuation of the cylinder  138 . An alternative embodiment of a pusher arm as the pusher arm  122  is described in EP 819 382 B1, in particular with reference to  FIG. 18  thereof. 
     The selective removal of a bird  113 ′ from a product carrier  3  by means of the removing device  115  will now be described hereinafter. 
     The starting situation is the situation shown in  FIG. 6  or  FIG. 7 a    insofar as the pusher arm  121  is in the passive position illustrated in the dotted line. In said starting position, also the ejector arm  122  is in the passive position. The control system of the slaughter line  101  delivers the command to the control unit of the removing device  115  that a bird  113 ′ must be removed from the associated product carrier  3 . As soon as the bird in the adjacent downstream product carrier  3  offers space for this, the pusher arm  121  will move from the passive position to the active position. In the situation shown in  FIG. 7 a   , the upstream leg  114  of the bird  113 ′ will be pushed from the lower end  12  of the slot  8  in question to approximately halfway the length of said slot  8  by and during the movement of the pusher arm  121  to the passive position. During the movement of the slaughter line, the downstream leg  114  of the bird  113 ′ will strike the pusher arm  121  and be pushed aside in the direction of the open end  11  of the associated slot  8 , also to a position approximately halfway the length of said slot  8 . Once the bird  113 ′ is subsequently positioned directly opposite the ejector arm  122  ( FIG. 7 b   ) as a result of the movement of the slaughter line, the ejector arm  122  will be briefly moved from the passive position to the active position and back to the passive position again. During said movement from the passive position to the active position, the ejector arm  122  pushes, more specifically bumps, the legs  114  of the bird  113 ′ toward the open end  11  out of the slots  8  ( FIG. 7 c   ). The pusher arm  121  will then pivot back to the passive position. This can take place at the same time or shortly after the ejector arm  122  has pivoted back to the passive position, but it is also conceivable for the pusher arm  121  to pivot back to the passive position again (shortly) before the ejector arm  122  moves to the active position. 
     The above process is also shown in the diagram of  FIG. 10 , in which the vertical axis indicates the lateral movement (i.e. in horizontal direction perpendicular to the direction of movement  24 ) of the end of the pusher arm  121  and of the ejector arm  122  and also of the legs  14  of a bird  13 ′. The legs  14  move jointly with the ejector arm  122  during the stroke from the active position to the passive position. Although the return movement of the pusher arm  121  to the passive position takes place between the forward movement of the ejector arm  122  and the return movement of the ejector arm  122  in the diagram, said movement could also take place shortly before the forward movement of the ejector arm  122  or after, for example shortly after, the return movement of the ejector arm  122 . Typically, the interval between the forward movement of the first pusher arm  121  and the return movement of the ejector arm  122  could be 200 ms. 
       FIG. 8  shows how the removing device  115  can also be used for transferring birds in a transfer station comparable to the one shown in  FIG. 5 . 
     In the foregoing, the invention has been explained by means of an example in which birds, such as chickens, are processed. The invention is also suitable for use with other types of animals for slaughter, for example fish. A product carrier that might be used with fish, for example, is described in European patent application EP 13183012.7.