The invention relates to an indexing device for a carcass hook. More particularly, the invention relates to an improved indexing device for a revolving carcass hook for poultry. The indexing device ensures that the fowl is moved forwards in a correct orientation towards equipment on a processing line.

The processing of poultry carcasses, in which the poultry carcasses are divided into pieces, takes place substantially on automated processing lines. The poultry carcasses hang by their legs from hooks, and the hooks are moved along a suspended conveyor, a so-called overhead conveyor. The patent documents EP 0444782, EP 0882405 and EP 1488703 disclose examples of such processing lines. The poultry may be chickens, ducks, geese or turkeys.

The conveyor is provided with a plurality of movable hooks. The conveyor carries the hooks with the hanging poultry past various cutting devices that cut off a piece each of the carcass until the whole carcass has been fully cut up. The hook is connected to the conveyor by a turning plate and in such a way that the hook cannot rotate around the vertical axis of the turning plate. Along the conveyor, the processing line is provided with guiding devices cooperating with the turning plate. The guiding devices are arranged to rotate the turning plate around the vertical axis. The guiding devices will determine whether the poultry carcasses are moved forwards, backwards or sideways along the conveyor, seen in the moving direction.

For the poultry carcasses to be moved in correctly over a cutting device, or possibly be guided past the cutting device, it is vital that the turning plate is in the correct position because the hook with the fowl is rigidly connected to the turning plate along the vertical axis of the turning plate. The patent documents EP 0444782, EP 0882405 and EP 1488703 show examples of how this can be achieved.

A drawback of one or more of the known solutions is that in spite of different guides, pegs and notches with which the devices are provided, faults do occur from time to time by the turning plate not being turned into the correct position. This may result in alarms being set off and processing lines being stopped for the fault to be repaired. The fault may also result in the processing line stopping by itself. The fault must be localized and repaired before the processing line can start again. Such faults result in reduced uptime in a highly automated processing plant.

The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through features which are specified in the description below and in the claims that follow.

In a first aspect, the invention relates to an indexing device for use in a hook holder, the hook holder being provided with a shank which, at one end portion, is arranged to be moved forwards by an overhead transporter, the hook holder being arranged, at one end portion, to hingedly hold, rotatably around a vertical axis, a hook which is arranged to hold a hanging fowl, the hook holder being provided with a rotatable turning plate arranged to cooperate with at least one guide member along the conveyor, the turning plate being arranged to rotate the hook around the vertical axis; the shank being provided with a bore arranged to accommodate a spring and a locking piece, a locking pin being positioned in an opening in the locking piece, and the end portions of the locking pin being positioned in slots, directed axially in the wall of the shank, and projecting beyond the outer sheath surface of the shank, the end portions of the locking pin resting on the upward rim surface of a bushing, characterized by the indexing device comprises an upward rim surface of the bushing being undulated in the circumferential direction, including wave troughs and wave crests. The end portions of the locking pin may be provided with bodies which are rotatable around the longitudinal axis of the locking pin. The rotatable body may consist of a ball bearing.

In what follows, an example of a preferred embodiment is described, which is visua lized in the accompanying drawings, in which :

Figure 1 shows an exploded drawing of a prior-art hook holder, viewed from below;

Figure 2 shows, on a larger scale, a perspective view of a prior-art bushing;

Figure 3 shows, on a different scale, a perspective view of the invention; and Figure 4 shows, on the same scale as figure 3, a side view and a section of the invention.

In what follows, especially the teachings of EP 1488703 are referred to as the prior art. The description of the prior art will make it easier to understand the construction and operation of the invention. Directions are indicated relative to the position of application, in which a hook holder is hanging down from the conveyor.

In the figures, the reference numeral 1 indicates a hook holder. Figure 1 shows the hook holder 1 as it is shown in EP 1488703 and this will be described in what follows: The hook holder 1 comprises an arm 11 provided with a lug 12. The arm 11 is fixed to a housing 13. The housing 13 is provided with a through-going opening 14, the axis of the through-going opening 14 coinciding with the vertical axis 9 of the hook holder 1.

The hook holder 1 further comprises a turning plate 16. In the figure, the turning plate 16 is shown as a two-part turning plate 16, wherein the turning plate 16 comprises an upper turning plate 16' and a lower turning plate 16". The upper turning plate 16' and the lower turning plate 16" are held together with screws (not shown). The turning plates 16' and 16" are provided with a plurality of pegs 17 projecting upwards and downwards, respectively, from the turning plates 16' and 16". The pegs 17 cooperate with guiding devices, not shown, along an overhead conveyor (not shown). The turning plates 16' and 16" are provided with central openings 18, respectively 18' and 18".

The hook holder 1 further comprises a hinge piece 2. The hinge piece 2 comprises hinge lugs 21 projecting downwards. The hinge lugs 21 are provided with through- going horizontal bores 22. In its upward-projecting portion, the hinge piece 2 is provided with a sleeve 23 which complementarily fits the housing 13. A through-going opening 24 extends through the hinge piece 2 along the vertical axis 9 of the hook holder 1. In its lower mouth portion 26, the opening 24 is formed with a cornered circumference, whereas, for the rest, the opening 24 is formed with a circular portion (not shown). The hinge piece 2 is provided with an outer collar 27. On its bottom side, the outer collar 27 is formed with a stepping 28 which complementarily fits the opening 18" of the lower turning plate 16".

The hook holder 1 further comprises a shank 3. The shank 3 comprises an upper end portion 30 and a lower end portion 39. The end portion 30 is provided with a lug 31. The shank 3 is provided with a bore 32 which coincides with the vertical axis 9 of the hook holder 1. The bore 32 extends from the end portion 39 towards the second end portion 30. The bore 32 forms an opening 33 at the end portion 39. The end portion 39 is provided with two through-going slots 35 elongated in the axial direction, extending from the outer sheath surface 36 of the shank 3 to the bore 32. The two slots 35 are positioned diagonally in the end portion 39. Only one slot 35 shows clearly in figure 1. On its outer sheath surface 36, the shank 3 is provided with a collar 37. The shank 3 complementarily fits the through-going opening 24 in the hinge piece 2.

The hook holder 1 further comprises a spring 40 (not shown in figure 1) which is positioned in the bore 32 of the shank 3, see figure 4. The spring 40 rests at its upper end 41 against the closed end portion 320 of the bore 32. At its lower end 42, the spring

40 rests against a cylinder-shaped locking piece 43. The locking piece 43 is provided with a through-going, horizontal opening 45. In its lower end face 46, the locking piece 43 is provided with a screw hole 47 for a set screw (not shown). The locking piece 43 complementarily fits the bore 32 of the sha nk 3.

The hook holder 1 further comprises a bushing 5. In its upper portion 50, the bushing 5 is formed with a circular circumference which complementarily fits the circular portion of the opening 24 in the hinge piece 2. In its lower portion 59, the bushing 5 is formed with a cornered circumference complementarily fitting the cornered mouth portion 26. The bushing 5 is shown in greater detail in figure 2. On its upper side, the bushing 5 is provided with a circular central cut-out 51 coinciding with the axis 9. The cut-out 51 is complementary to the lower end portion 39 of the shank 3. The cut-out 51 creates a rim 52 in the upper portion 50 of the bushing 5. In its upward surface 53, the rim 52 is provided with radial U-shaped recesses 54, 54'.

The spring 40 is held in place in the bore 32 of the shank 3 by a locking pin 6 (not shown in figure 1, but shown in figure 4) being passed horizontally through the two slots 35 of the shank and the horizontal opening 45 in the locking piece. The longitudinal axis of the locking pin 6 will then coincide with the axis 92 through the slots 35 and the axis 93 through the opening 45. In figure 1, the locking piece 43 is shown rotated around the axis 9 relative to its position of application. The end portions 60, 60' of the locking pin 6 both project beyond the sheath surface 36. The locking piece 43 with the locking pin 6 is axially and resiliently movable in the bore 32 as the locking pin 6 can be moved axially in the slots 35.

When the housing 13, the turning plate 16, the hinge piece 2, the assembled shank 3 and the bushing 5, have been assembled, the lug 31 of the shank 3 will project above the housing 13. The lug 31 and the lug 12 of the arm 11 are attached to the overhead conveyor not shown. Thus, the shank 3 and the housing 13 cannot rotate around the vertical axis 9. The hinge piece 2 is rotatably positioned around the axis 9 in the hous- ing 13. The turning plate 16 is rigidly attached to the hinge piece 2 and rotatable around the axis 9. The bushing 5 rotates together with the hinge piece 2 because the cornered lower portion 59 of the bushing 5 is formed complementary to the cornered mouth portion 26 of the hinge piece 2. The shank 2 and housing 13 are attached to the overhead conveyor and, in all essentials, cannot move axially along the axis 9. The outer collar 27 of the hinge piece 2 butts against the lower portion of the housing 13, and the hinge piece 2 cannot move axially along the axis 9. The turning plate 16 butts against the bottom side of the outer collar 27 and the turning plate cannot move axially along the axis 9. The bushing 5 can move axially along the axis 9 relative to the shank 3 and the turning plate 16.

When assembled, the two projecting end portions 60, 60' of the locking pin 6 will rest in respective, diagonally opposite, paired, radial, U-shaped recesses 54, 54' in the rim 52 of the bushing 5. The bushing 5 is held in place axially from the bottom side by means of a depending hook (not shown) which is hinged to the hinge lugs 21 and rotatable around the axis 91. The hinge portion of the hook is arranged to rest against the bottom side of the bushing 5. This is done in such a way that the bushing 5 is pressed against the projecting end portions 60, 60' of the locking pin 6, which compresses the spring 40 via the locking piece 43 (see figure 4). The locking pin 6 and the bushing 5 form an indexing device for the hook.

As described before, the turning plate 16 cooperates with guiding devices not shown. On contact with the pegs 17 of the turning plate 16, the guiding devices will rotate the turning plate 16 around the axis 9. The turning plate 16 rotates together with the hinge piece 2. The depending hook rotates around the axis 9 as well. The bushing 5 rotates around the axis 9 together with the hinge piece 2. The locking pin 6 is not rotatable around the axis 9. When the bushing 5 is rotated, the end portions 60, 60' of the locking pin 6 are carried out of the paired, U-shaped recesses 54, 54' and will resiliently butt against the upward surface 52 until the end portions 60, 60' of the locking pin 6 have been carried into the pair of neighbouring recesses 54'. This is to ensure that the hook has been rotated correctly. It has turned out that the end portions 60, 60' of the locking pin 6 may remain lying on top of the upward surface 53 after the guiding devices have terminated their contact with the pegs 17. Thus the hook has not been rotated correctly around the axis 9.

The invention is shown in figures 3 and 4.

The invention comprises a shank 3. The shank 3 comprises an upper end portion 30 and a lower end portion 39. The end portion 30 is provided with a lug 31. The shank 3 is provided with a bore 32 (see figure 4) which coincides with the vertical axis 9 of the hook holder 1. The bore 32 extends from the end portion 39 towards the end portion 30. The bore 32 forms an opening 33 at the end portion 39. The end portion 39 is provided with two through-going slots 35 elongated in the axial direction, which extend from the outer sheath surface 36 of the shank 3 to the bore 32. The two slots 35 are positioned diagonally in the end portion 39. Only one slot 35 shows clearly in figure 3. On its outer sheath surface 36, the shank 3 is provided with ball bearings 38. In figures 3 and 4, two ball bearings 38 are shown. The ball bearing 38 complementarily fits the through-going opening 24 of the hinge piece 2. The ball bearing 38 is of a kind known per se and is not described any further. The invention further comprises a bushing 5. In its upper portion 50, the bushing 5 is formed with a circular circumference complementarily fitting the circular portion of the opening 24 in the hinge piece 2. The bushing 5 is provided with a cornered projecting collar 55 which complementarily fits the cornered mouth portion 26. On its upper side, the bushing 5 is provided with a circular central cut-out 51 which coincides with the axis 9. The cut-out 51 is complementary to the lower end portion 39 of the shank 3. The cut-out 51 creates a rim 52 in the upper portion 50 of the bushing 5. The upward surface 53 of the rim 52 is undulated and forms wave troughs 56 and wave crests 57 in the circumferential direction.

In one embodiment, the invention also comprises providing the projecting end portions 60, 60' of the locking pin 6 with a body 61 which is rotatable around the longitudinal axis 69 of the locking pin 6. The rotatable body 61 may consist of a ball bearing 61. The rotatable body 61 is pressed against the upward surface 53 by the spring 40 via the locking piece 43 and the locking pin 6. The rotatable body 61 cannot rest on a wave crest 57, but will seek towards a wave trough 56. It is thereby ensured that the hook has been correctly rotated after the guiding devices have terminated their contact with the pegs 17.