Patent Application
20100040451
The present invention relates to an intermediate storage device as claimed in the preamble of claim 1, a stacking unit with such an intermediate storage device as claimed in claim 9 and a method for operating the intermediate storage device as claimed in claim 13.
An intermediate storage device in terms of the present invention refers to a device for taking, temporarily storing and conveying stacks of flat products, in particular printed products. Along with such an intermediate storage device, a stacking unit also includes a stacking device connected upstream for forming a stack of flat products.
A device for the controlled conveying of stacks of printed products lying one on top of the other is known, for example, in EP 1 273 542. The device, in this case, has a conveying-effecting traction means circulating about two deflecting rollers, by means of which stacks resting thereon are able to be conveyed. Support bars hold the stacks upright and in constant form. A conveying-effecting region of the traction means is slanted and ends at the level of a horizontally oriented guide table. The conveying speed of the stack can be slowed or controlled by means of a control device.
It is the object of the present invention to optimize a stack processing sequence between a supplying device, in particular a stacking device, and a stack processing device, which have different processing speeds or pulsings.
This object is achieved by an intermediate storage device as claimed in claim 1, a stacking unit with such an intermediate storage device as claimed in claim 9 and a method for operating the intermediate storage device as claimed in claim 13.
The intermediate storage device according to the invention, which is positioned between a supplying device connected upstream for preparing stacks of flat products, in particular printed products, and a stack processing device connected downstream for processing the stack, and the method according to the invention for operation of the same make it possible to take, store temporarily and deliver the stacks from or to the nearby device in a pulse-adapted manner. To this end, the intermediate storage device is provided with at least one conveying means, which has an upper run that is displaceable in a conveying direction, and on which, for conveying the stack, a bottommost flat product of the stack rests at least in a partial manner. In addition, the intermediate storage device has a control device that can generate a signal for controlling a conveying speed of the conveying means,
According to the invention the control device is capable of receiving a control signal from the supplying device connected upstream and an additional control signal from the stack processing device connected downstream and, in dependence on the control signal and on the additional control signal, is capable of controlling the conveying speed of the conveying means, adapting it to the pulsing of the supplying device and of the stack processing device. In this case, the ability to receive the control signals is provided by a functional, preferably electric connection between the transmitters of the control signals, that is the supplying device and the stack processing device, and the receiver, that is the control device of the intermediate storage device. The ability also includes the control device being able to interpret and process the control signals.
Through the ability of the intermediate storage device to communicate with the supplying device connected upstream and the stack processing device connected downstream, the stacks can be taken, temporarily stored and delivered in each case in a manner that is adapted to the pulsing of the intermediate storage device and of the supplying device each time at an optimally coordinated conveying speed. In this way, it is possible to adapt, for example, the pulsing of a stack processing device with a fairly long processing time to a supplying device, in particular a stacking device, with a quicker processing time. By adapting the pulsing and conveying speed, including the possibility of a static intermediate storage of stacks, the stack processing sequences are optimized in terms of reduced cycle times or higher processing rates.
In a particularly preferred specific embodiment, the control device, when the intermediate storage device is occupied, is also capable of sending a backlog signal to a stack controlling device of a stacking device that is in the form of a supplying device. The stack controlling device is designed in such a manner that, when it receives a backlog signal, it can direct the stacking device to adapt in a corresponding manner, in particular to increase, the number of flat products for the stack to be formed. Thus, for example, it is possible to prefer the forming of stacks with a greater number of flat products in the stack forming sequence. In this way it is possible to utilize, in an optimum manner, the time in which the intermediate storage device is still occupied with a stack, to form, where applicable, larger stacks with a greater number of flat products that are subsequently necessary. Consequently, it is ensured that the stacking device, as a rule operated at a higher stacking pulse than a stack processing device, can form stacks, where applicable also stacks of different heights, in an almost continuous manner with interruptions that are as short as possible, and does not have to be adapted directly to the generally slower pulsing of the stack processing device. This results in a further optimized stack processing sequence and in shorter cycle times or higher stack processing rates.
The stacking unit according to the invention, along with the intermediate storage device according to the invention for taking, temporarily storing and conveying stacks, comprises a stacking device connected upstream for forming the stack from flat products.
Particularly preferred specific embodiments of the intermediate storage device, the stacking unit and the method for operating the intermediate storage device are provided with features detailed in the dependent claims.
Two particularly preferred specific embodiments of the present invention are described below by way of drawings in which, in detail, in a purely schematic manner:
The stacking unit 10 according to the invention shown in
The stacking device 12 has a pallet 22 for supporting the flat products 16 and two oppositely situated ejectors 26 defining a stack shaft 24. The stack shaft 24, in this case, is defined at least partially on the support side by the pallet 22 and at each corner by ejector elements 28 that are angular in cross-section. In this case, each ejector 26 has four ejector elements 28 which are positioned so as to be able to rotate at two strip-shaped drive members 30 that are each displaceable independently of each other and two of which, in each case, are situated diametrically opposite each other. A stacking device 12 of this type in the form of a rotary lifting table is described for example in EP 1 445 224.
As soon as a predetermined number of flat products 16 have come to lie one on top of the other in the stack shaft 24 of the stacking device 12 for forming the stack 14, the stack 14 is pushed by means of the ejector elements 28 of the ejector 26 in an ejection direction A out of the stacking device 12 in the direction of the intermediate storage device 18 over the pallet 12.
In this case, a bottommost flat product 16u of the stack 14 is supported at least partially on a support surface 32 of an upper run 34 of a conveying means 36 associated with the intermediate storage device 18. The conveying means 36 is, for example, formed by a belt conveyor or a chain conveyor. The conveying means 36, which is driveable by an electric drive motor 38 via a drive axle 40 and a driving roll 42 positioned thereon in a non-rotatable manner, in this case, is orientated in such a manner that a conveying direction T defined by the direction of movement of the upper run 34 of the conveying means 36 extends parallel to the ejection direction A.
When the stack 14, ejected by the stacking device 12, is taken by the intermediate storage device 18, a longitudinal centre section of the bottommost flat product 16u is supported on the support surface 32, whilst, with reference to the conveying direction T, the outer edge regions 44 of the bottommost flat product 16u slide on sliding faces 46 of sliding plates 48 positioned on both sides of the conveying means 36. The support surface 32 of the upper run 34 of the conveying means 36, in this case, is orientated in its height in such a manner that, in the unloaded state, it extends substantially at the height of a stack contact plane 50 that is defined by the pallet 22. The sliding faces 56, when viewed in a vertical manner, extend at a small distance below the support surface 32 such that when the stack 14 is supported on the conveying means 36, it has a slight roof-shaped bulge, as can be seen in
With reference to the conveying direction T, two stop devices 52 are positioned on both sides of the conveying means 36 above the slide plates 48. The stop devices 52 each have two rotatably mounted hollow cylinders 54, which are spaced apart in the conveying direction T and are substantially vertically orientated for driving a chain belt 56 that is produced from plastics material. Stop elements 58, which are situated diametrically opposite one another, are secured in each case to the chain belt 56, said stop elements having substantially vertically orientated, planar stopping faces 60 for supporting front side edges 62 of the stack 14 advancing in the conveying direction. The stop elements 58 serve to stabilize the shape of the stack 14 when it is being conveyed in the intermediate storage device 18. The hollow cylinders 54 of the stop devices 52 of the stack processing device are each driven synchronously with one another via a servomotor 64 with a belt drive or chain drive 66 installed downstream, whereas the hollow cylinders 54 of the stacking device are each entrained with the chain belt 56. To adapt to different formats of flat products 16, it is possible to move the stop devices towards one another and away from one another as a result of elongate holes (not shown).
Control of the servomotor 64 and of the stop elements 58 driven thereby and of the drive motor 38 for influencing the conveying speed of the conveying means 36 is effected by means of a control device 68 of the intermediate storage device 18. This preferably electrically designed control device 68 is capable of receiving a control signal from the stacking device 10 connected upstream and an additional control signal from the stack processing device 20 connected downstream and, in dependence on the control signal and on the additional control signal, is capable of controlling the conveying speed of the conveying means 36, for taking, storing temporarily and delivering of the stack 14, adapting it to the pulsing of the supplying device 10 and of the stack processing device 20.
Over and above this, when the intermediate storage device 18 is occupied by a stack 14, the control device 68 can send a backlog signal to a stack controlling device 70 of the stacking device 12 that is capable of receiving said signal. As is explained in more detail below in conjunction with
In particular the exchange of electrical signals between the stack controlling device 70, which also controls the driving members 30 and consequently the movement of the ejecting elements 28, and the control device 68, which influences the conveying speed of the conveying means 36, means that they are coordinated and tuned to each other in such a way that a stack processing sequence is carried out in a pulse-optimized manner when the stack 14 is ejected from the stacking device 12 and the stack 14 is taken by the intermediate storage device 18. Along with a physically separate arrangement of the control device 68 and the stack controlling device 70, it is naturally also possible to integrate the two control devices 68, 70 spatially. Through the exchange of control signals, along with controlling the conveying speed of the conveying means 36, it is also possible for the purposes of adapting the pulsing to bring said conveying speed in line with the ejecting speed of the stacking device 12 and the taking speed of the stack processing device 20. A conveying speed harmonized in this manner is especially indispensable when ensuring the integrity and shape stability of the stack 14 when it is being conveyed.
In the view of the intermediate storage device 18 according to the invention in
In contrast to the intermediate storage device 18 shown in
As mentioned for the intermediate storage device 18 in conjunction with
The two conveying means 36.1, 36.2 are driven independently from one another preferably by asynchronous motors. The control device 68 of the intermediate storage device 18, along with the features already mentioned above in conjunction with
It must be mentioned at this point that certain regions of the conveying path of the stacks 14 in the intermediate storage device 18 can be provided with passively entrained rollers 76, as they are shown, for example, at the stack processing device end in the intermediate storage device 18 in
In each case, the stack contact plane 50 of the stacking device 12, at least at the intermediate storage device end, is positioned substantially at the height of the first support surface 32.1 of the first upper run 34.1 and a stack processing plane of the stack processing device 20, at least at the intermediate storage device end, is positioned substantially at the height, at the stack processing device end, of the sliding faces 46. In addition, the first support surface 32.1 of the first conveying means 36.1 and the second support surface 32.2 of the second conveying means 36.2 extend substantially in a common plane that preferably extends horizontally.
As has already been explained in conjunction with
This control behavior can lead, for example, to the varying height of the stack 14 represented schematically along the time axis t in
By way of example, a stack processing sequence of the stacking unit according to the invention is now described in conjunction with
As can be seen in the sequence diagram in
As soon as the stack 14 is slid onto the conveying means 36.1 that is moving at an identical speed as the stack 14, the stop elements 58 identified by M are also accelerated evenly up to the speed vmax and then leading in front of the stack 14 are entrained at the conveying speed of the first conveying means 36.1(M2). The advancing ejector elements 28 (M0) then brake on the side of the ejector device 26 remote from the stack shaft 24 and move to a position for rest situated diametrically opposite the start position of the ejector elements 28 identified by M. Directly after the rearward ejector element 28 pushing out the stack 14 has reached a reversal point at the intermediate storage device end, it is also braked and initially accelerated in the opposite direction and then braked again so that it assumes the start position of the ejector element 28 associated originally with the front side edge 62 of the stack 14.
The stop elements 58(M1) and the first conveying means 36.1(M2), which has already been accelerated to the speed vmax, continue moving at the speed vmax until the stack 14 has been completely taken over. Directly before the stack 14 is taken over by the second conveying means 36.2 (M3), its additional conveying speed is also increased from the idle state to the speed vmax. As soon as the stack 14 is no longer resting on the first conveying means 36.1, said means, as also the leading stop elements 58 and the second conveying means 36.2, is braked evenly to a speed v2, which is less than the speed v1. The speed v2 corresponds to the speed at which the following stack processing device 20 can take the stack 14. In other words, through the intermediate storage device 18, the speed vmax at which the stack 14 is ejected from the stacking device 12 is adapted to the taking speed v1 of the stack processing device 20.
As soon as the stop elements 58 associated with the front side edge 62 have reached their reversal point at the stack processing device end, they are accelerated again and are stopped at an end position that is situated diametrically opposite their original start position on the side remote from the conveying means 36.1, 36.2. The stop elements 58 now situated diametrically opposite at the original start position are ready for the transfer of another stack 14. Just as the stop elements 58, the first conveying means 36.1 is also braked to an idle position directly after the stack 14 has left it. The second conveying means 36.2 runs at the speed v2 until the stack 14 has been completely transferred by the stack processing device 20.
Although the sequence diagram by way of example in
As already mentioned beforehand, it is possible as soon as the stack 14 is no longer resting on the first conveying means 36.1—for the first conveying means 36.1 to take over another stack 14 from the stacking device 12. This results, along with the advantage of adapting the speed to the respectively associated stacking device 12 or stack processing device 20, in an optimized, more rapid stack processing sequence for the stacks 14, in particular also in a quicker cycle for smaller, so-called top or standard stacks, and enables stacks to be formed with any stoppages or interruptions being as short as possible.
| Number | Date | Country | Kind |
|---|---|---|---|
| CH2008 01306/08 | Aug 2008 | CH | national |
