Transfer device

Abstract

A transfer device, adapted to convey an object in a conveying direction, and selectively transfer an object in a second direction angled to the conveying direction; the transfer device having a plurality of belt carriers, circumferentially running along the transfer device, a traction belt circumferentially running along the transfer device, along which the plurality of belt carriers is arranged; circumferentially running transfer belts forming an upper run and a lower run; wherein each belt carrier carries a transfer belt, which protrudes above the belt carrier, and wherein the plurality of transfer belts is defining a conveying plane, on which the object comes to rest during conveying; wherein for laterally transferring the object the transfer belts are selectively driven. The transfer device also has a tensioner, which is adapted to change the tension of the traction belt.

Claims

1. A transfer device (20), adapted to convey an object (9) in a conveying direction (FR), and selectively transfer an object (9) in a second direction (A) angled to the conveying direction (FR), the transfer device (20) comprising: a plurality of belt carriers (21), circumferentially running along the transfer device (20), a traction belt (27) circumferentially running along the transfer device (20), along which the plurality of belt carriers (21) is arranged; a tensioner (7), which is adapted to change a tension of the traction belt (27); circumferentially running transfer belts (24) forming an upper run (273) and a lower run (274); wherein each belt carrier (21) carries a transfer belt (24), which protrudes above the belt carrier (21), and wherein the plurality of transfer belts (24) defines a conveying plane (FE), on which said object (9) comes to rest during conveying; wherein for laterally transferring the object (9) the transfer belts (24) are selectively driven; wherein the tensioner (7) comprises a force limiter (75), limiting tensioning force (P) which is applied by a force storage (72) to the traction belt (27); and wherein a distance holder (72) and/or the force limiter (72) is adapted to bridge a length of a spring (27).

2. The transfer device (20) according to claim 1, characterized in that the tensioner (7) comprises the force storage (72), in particular the spring (72), which is adapted to provide the tensioning force (P).

3. The transfer device (20) according to claim 1, characterized in that the traction belt (27) is wound around two deflection wheels (291, 292), and that the tensioner (7) comprises the distance holder (75), wherein the distance holder (75) is adapted to ensure a minimum distance between said two deflection wheels (291, 292).

4. The transfer device (20) according to claim 1, characterized in that the distance holder (72) is the force limiter (72).

5. The transfer device (20) according to claim 3, characterized in that the distance holder (72) and/or the force limiter (72) is a bushing, located coaxially around the spring (72).

6. The transfer device (20) according to claim 1, characterized in that the transfer device (20) is able to selectively operate the traction belt (27) in two directions (R1, R2), in particular, the traction belt (27) can selectively be driven in a manner, that in a first operation mode a driven wheel (291) pulls the upper run 273 (direction R1) and that in a second operation mode a driven wheel (291) pulls the lower run (274) of the traction belt (27).

7. The transfer device (20) according to claim 6, characterized in that the transfer device (20) comprises a plurality of deflection wheels (291, 292) for deflecting the traction belt (27), wherein all deflection wheels (291, 292) deflect the traction belt inwardly.

8. The transfer device (20) according to claim 7, characterized in that the plurality of the deflection wheels (291, 292) comprises exactly two deflection wheels (291, 292) per traction belt (27).

9. Use of a transfer device (20) according to claim 8, wherein for adjusting the tension of the traction belt (27) the tensioner (7) is operating in a manner that after the belt tension is adjusted correctly the distance holder and/or the force limiter (75) is held with play.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The drawings described here are used to provide further understanding of the present disclosure and form a part of the present application. Illustrative embodiments of the present disclosure and description thereof are used for explaining the present disclosure, but do not improperly limit the present disclosure. In the drawings:

(2) FIG. 1 is a schematical top view of a conveying arrangement having an inventive transfer device.

(3) FIG. 2 is an overall perspective view of an inventive transfer device.

(4) FIG. 3 is a schematical longitudinal section through a part of the conveying arrangement of FIG. 1.

(5) FIG. 4 is a cross section through the belt carrier of the transfer device of FIG. 2.

(6) FIG. 5 is schematically a side view of a traction belt and a tensioner of the transfer device of FIG. 2.

(7) FIG. 6 is schematically a top view of the traction belt and the tensioner of the transfer device of FIG. 2.

(8) FIG. 7 is schematically a top view of the tensioner of FIG. 5, where panel a) shows a released state; panel b) shows a tensioned state; and panel c) shows an over-tensioned state.

(9) FIG. 8 depicts the tensioner of FIG. 5 in a perspective view, where in figure panel b) the limiting bushing is shown transparent.

DETAILED DESCRIPTION OF THE INVENTION

(10) FIG. 1 shows a conveyor arrangement 1 having a sorting functionality, including an inventive transfer device 20. There is a plurality of conveying devices 10 for conveying objects 9, arranged one behind the other in a conveying direction FR. At first, objects 9 are fed in via a conveyor section 10a. These objects are then transferred to a first transfer device 20a. This is followed by further conveyor sections 10b . . . d and further transfer devices 20b, 20c, whereby the transfer devices 20 each are arranged between two conveying devices 10. The conveying devices 10 can be designed as a roller conveyor section 10a, 10d or as a belt conveyor section 10b, 10c.

(11) Each of the transfer devices 20 selectively transfers selected objects 9 out of the conveying direction FR and into a transfer area 3 lateral of the conveying direction FR. For this purpose, object 9 is accelerated in the lateral direction A, at least for a short time.

(12) In contrast to conventional crossbelt sorters, the conveyed object 9 can be taken over by such a conveyor line, which transfers the object 9 to the transfer area both in the conveying direction FR and within a conveying plane FE of the transfer device 20. It is also possible to transfer the conveyed object 9 from the transfer device 20 to a downstream conveying device 10 in which the conveyed object 9 is taken over both in the conveying direction FR and in the conveying plane FE of the transfer device 20.

(13) FIGS. 2 and 3 show a transfer device, which is based on the transfer device shown in the earlier application WO 2011/122792 A2.

(14) The transfer device 20 has a frame 28 with, for example, four legs. The transfer device 20 forms a conveying surface 201 on which an object 9 (not shown here) can be conveyed in conveying direction FR. The conveying surface 201 defines the conveying plane FE.

(15) The transfer device 20 has a guide 23 (FIG. 3) along which a plurality of belt carriers 21 are arranged. The belt carriers 21 are movably arranged on the guide 23 such that the belt carriers 21 are moved in a circuit, in particular, a closed loop. At the first side, here the upper side, the belt carrier 21 moves in the conveying direction FR. At a first transfer location 26a, the conveyed object 9 is provided from the upstream conveyor section 10a and arranged on an upper side of the belt carrier 21. At a second transfer location 26b, the conveyed object 9 is provided to a downstream conveyor section 10c (not shown) and arranged on an upper side of another conveyor, provided that it has not previously been transferred laterally. A conveying area 26f is defined between the transfer locations 26a, 26b.

(16) Each belt carrier 21 carries a transfer belt 24, the longitudinal extension of which is aligned in the traverse direction Q (see FIG. 2), which is 90 angled to the conveying direction FR. The transfer belt 24 protrudes above the belt carriers 21 and thus constitutes a support surface 241 which defines the conveying plane FE and on which the object 9 lying on it comes to rest.

(17) The belt carriers 21 are driven by a drive 29 in the conveying direction FR (FIG. 2). Therefore a traction belt 27 is provided (FIG. 4), along which the plurality of belt carriers 21 is arranged. A connector 271 (FIG. 4) is adapted to connect the belt carriers 21 to the traction belt 27.

(18) The traction belt 27 has, in particular on its inner side, a plurality of engagements 272 (FIG. 4), which positively engages with a driven wheel 291, e.g. which may be of a drum motor or a driven wheel 291 separate to a motor. The positive engagement 272 serves to ensure, that the belt carriers 21 are driven at a speed defined by the drive 29.

(19) For more details of the structure and the transfer functionality, reference is made to earlier application WO 2011/122792 A2, which is incorporated herein by reference in its entirety.

(20) FIGS. 5 to 8 show a tensioner 7, with the help of which the tension of the traction belt 27 can be adjusted.

(21) Thereby, FIGS. 5 and 6 show schematically the tensioner 7 along with the traction belt 27, which is wound around two deflection wheels 291, 292, one of which is in addition a driven wheel 291. Some exemplary belt carriers 21 are depicted.

(22) The traction belt 27 according to the invention is arranged in the form of a head or tail configuration. In such a configuration at least one of the deflection wheels contacting the upper run 273 is a drive wheel 291.

(23) The inventive tensioner 7 has a threaded rod 71, which is attached to an axle 29A of one of the deflection wheels 292. The threaded rod 71 passes a stop 79. The stop 79 is fixedly attached to the frame 28.

(24) The stop 79 is located between a screw nut 73 and the deflection wheel axle 29A. The screw nut 73 is screwed on the threaded rod 71.

(25) Between the screw nut 73 and the stop 79 a spring 72 is located. By turning the screw nut 73 in the correct direction, the spring 72 is set under tension, resulting in a pulling or tensioning force P, pulling the threaded rod 71 in the direction away from the other deflection wheel 292, leading to tensioning the traction belt 27.

(26) Turning the screw nut 73 can be done manually with the help of a tool 710, in particular a wrench. Alternatively, turning the screw nut 73 can be done by an actuator 711 upon receiving of a control signal 712.

(27) A limiting bushing 75 is located coaxially around the spring 72 and axially between stop 79 and the screw nut 73.

(28) The positive drive connection between said driven wheel 291 and said traction belt 27 requires a certain minimum belt tension. At the same time, it is important for the longevity of the traction belt 27 that it is not over-tensioned. Therefore the invention proposes the following method of adjusting the tension and maintaining the tension over the lifetime.

(29) During installation of the transfer device 20, the traction belt 27 is initially in a non-tensioned state (see FIG. 7, panel a). Now the limiting bushing 75 is held loose between the screw nut 73 and the stop 79. The length S of the spring 72 is quite large meaning that the spring force is low. The spring 72 may be fully released.

(30) For increasing the belt tension, an operator is turning the screw nut 73 clockwise; for decreasing the belt tension, the screw nut 73 is to be turned counterclockwise.

(31) As the belt tension is increased, the spring 72 abuts the screw nut 73 and the stop 79. The spring is now compressed between screw nut 73 and the stop 79 (FIG. 7, panel b). The operator continues to tension the spring 72 up to an amount, where the bushing 75 is still held with an axial play between the stop 79 and the screw nut 73. A length S of the spring 72 is still larger than a length B of the limiting bushing 75. In this situation, there is a balance between the spring force and the tension force of the traction belt 27. Considering the spring parameters, the length S of the spring 72 represents a measure of the spring tension and thus of the tension of the traction belt 27.

(32) As the operator continues to increase the belt tension, also the limiting bushing 75 abuts both the screw nut 73 and the stop 79 and will be compressed between screw nut 73 and the stop 79 (FIG. 7, panel c). A length S of the spring 72 is equal to a length B of the limiting bushing 75.

(33) Now the limiting bushing 75 is clamped between the screw nut 73 and the stop 79 without any play. The omitted play is an indicator, that the maximum tension is achieved. Now the operator slightly releases the tension to get into a situation where the limiting bushing 75 is again held with play between the screw nut 73 and the stop 79.

(34) Alternatively, the turning of the screw nut 73 can be done by the actuator 711 (see FIG. 6).

(35) Within this application, the threaded rod 71 and the screw nut 73 is to be considered as a tensioning screw. Various other embodiments are possible to realize a tensioning screw.

(36) According to the above the clamping state of the limiting bushing 75 is an indicator for the correct tension of the traction belt 27.

(37) Optionally an intermediate plate 76 may be arranged between the screw nut 73 and the spring 72.

(38) The invention supports the following requirements according to which the transfer device 20 is operated: a) The transfer device 20 is able to selectively operate the traction belt 27 in both directions. Accordingly, the traction belt 27 can selectively be driven in a manner, that in a first operation mode, the driven wheel 291 pulls at the upper run 273 (direction R1) and that in a second operation mode, the driven wheel 291 pulls at the lower run 274 (direction R2). b) The wear condition of the traction belt 27 can always be monitored with the help of the limiting bushing 75. According to the specific embodiment of the figures, as long as the play of the limiting bushing 75 does not exceed a certain amount, the belt tension of the traction belt 27 is not subject to relevant belt length increase. Merely for reference, the requirement would not be supported in case that the deflection wheel axle 29A would be fixed to the frame 28 after adjusting the belt tension. Therefore is advantageous that the deflection wheel axle 29A is not fixed. c) Over its entire circumference the traction belt 27 is equipped with the belt carriers 21 (only a few of which are shown in FIG. 5). Additionally over its entire circumference, the traction belt 27 and the belt carriers 21 are subjected to a forced guidance by the guide 23. As a consequence, the traction belt 27 underlies a plurality of mechanical impacts preventing free oscillation of the traction belt 27. Conventional methods for monitoring the belt status by observing the oscillations cannot be applied in the present transfer device 20. d) The traction belt 27 is connected to the driven wheel 291 in a positive manner. This is important to enable speed synchronization with other devices cooperating with the transfer device 20. The positive drive connection always requires a minimum distance between the two deflection wheels 291, 292; otherwise, the traction belt 27 may jump over positive projections of the driven wheel 291, in case the distance between the two deflection wheels 291, 292 would be too small. The limiting bushing 75 ensures said minimum distance, so that the deflection wheels 291, 292 are not pulled too close to each other.

LIST OF REFERENCE SIGNS

(39) 1 conveyor arrangement 3 transfer area 7 tension device 9 object 10 conveying device 11 conveying roller 20 transfer device 201 conveying surface 21 belt carrier 23 guide 24 transfer belt 241 support surface 26a first transfer location 26b second transfer location 26f conveying area 27 traction belt 271 connector 272 engagements 273 upper run 274 lower run 28 frame 29 drive 291 deflection wheel/driven wheel 292 deflection wheel/undriven wheel 29A deflection wheel axle 7 tensioner 71 threaded rod 72 spring 73 screw nut 75 limiting bushing 76 intermediate plate/washer 79 stop 710 wrench 711 actuator 712 control signal A second, lateral direction B length of limiting bushing FR conveying direction FE conveying plane Q traverse direction P pulling/tensioning force R1 first operation direction/counterclockwise R2 second operation direction/clockwise S spring length