EP2367745B1 - Apparatus and method for transferring flexible flat objects - Google Patents

Description

The invention is in the field of conveyor technology and relates to an apparatus and a method for the transfer of flexible flat objects, in particular printed products, between two conveyors.

In conveyor technology and in particular in the field of printing technology, it is often necessary to transfer objects from grippers of a first gripper conveyor into grippers of a second gripper conveyor. For example, printed products from a printing press are often grouped, e.g. as a pair of two products, held and promoted by a common gripper. For further processing they must be separated. At least some of the products are therefore preferably transferred to grippers of the second gripper conveyor that each product is finally held individually.

The objects are often held congruently (with aligned edges) by a common gripper. For separating the jointly held objects, however, it may have advantages to clamp the objects in the gripper that their held edges are offset from each other (differentiated promotion).

In the EP-B 1321410 various cases of how a gripper-gripper transfer can proceed, procedurally outlined, for example: 1. Transfer two held by a common first gripper products to two consecutive second gripper; 2. transfer of every second product pair to two consecutive second grippers and subsequent splitting of the product pairs remaining in the first grippers; 3. Transfer only one of the products of the product pair to a second gripper and further conveying the product not handed over by the first gripper.

When separating pairs of subsidized objects, but also in the transfer of individual items from a first gripper to a second there are special requirements to the effect that the unaffected object edge is reliably positioned so that it is performed as accurately as possible in the open gripper mouth of the second gripper. This is especially true for flexible products, e.g. Printed products, important because they are held only at one edge of the product during conveying and due to external influences, e.g. Breeze, can change their position.

To stabilize the objects, the device provides according to EP-B 1321410 an unspecified flat pad on which rub the free edges of the article while the objects are conveyed by the first gripper, and which ends in the area in which approach the second gripper from below the free edges object.

The EP-A 1834911 describes a further transfer device in which individual objects are transferred from first grippers to synchronously moving second grippers. The second grippers are arranged below the first gripper. In a transfer area, the first grippers are opened so that the objects due to gravity in the mitbewegten open second gripper slide, which are then closed. To stabilize the objects during the transfer or in the transfer area, a stabilization device is provided which comprises two counter-rotating helical or spiral rotors. These each dive laterally into the spaces between the objects held by the first grippers and thus form a substantially vertically oriented planar support which moves with the objects over the entire transfer area, keeps them straight and ends only when the second gripper is closed is. A disadvantage of this arrangement is the relatively large volume, which is claimed by the side rotors, as well as the complexity of the entire stabilization device. Because the rotors have a certain extent both in the conveying direction and transverse to the conveying direction, which corresponds approximately to the length of the transfer region or the rotor diameter. The rotor diameter can not be made arbitrarily small, otherwise no reliable surface guidance of the objects would be possible. Finally, only the position of the objects in the conveying direction is predetermined by the stabilizing device, while the position of the free edge in the vertical direction remains indefinite.

If the first gripper conveys more than one item but not all are to be dispensed, the items remaining in the first gripper must be temporarily held when the gripper opens. For this the beats EP-B 1321410 Two alternative solutions: On the one hand, the use of a special gripper is proposed, which has two independent clamping areas and thus can selectively release an object while the other is still held. On the other hand, an additional auxiliary gripper conveyor is proposed, the auxiliary gripper are moved in the transfer area in synchronism with the first gripper and hold the items not to be dispensed during the opening of the first gripper and thereby retain in the open first gripper.

The problem with the differentiated promotion of multiple objects in a common gripper may be that the remaining in the gripper object due to the original offset does not have the optimum position relative to the gripper jaws or the pivot axis.

The invention is therefore based on the object of specifying an apparatus and a method for transferring flexible, flat objects from a first gripper conveyor to a second gripper conveyor, in which or in which the described disadvantages are avoided. In particular, according to a first aspect of the invention, especially with differentiated promotion with simple means, a position correction of the remaining objects in the gripper to be achieved.

The object is achieved by a device and a method having the features of claims 1 and 10, respectively. Advantageous further developments emerge from the dependent claims, the description and the drawings.

The device according to the invention comprises a first gripper conveyor with first grippers moved along a first gripper conveyor track for essentially hanging transport of the articles in a conveying direction. In this case, first object edges are detected by the first grippers. The objects are promoted individually or in groups; In the case of group-wise conveyance, the first object edges may lie on one another or be offset from one another within the gripper. There is also a second gripper conveyor with second grippers moving along a second gripper conveyor track. These pick up the objects by gripping a second edge of the object opposite the first edge of the object. In addition, at least one Actuating device for opening and closing the gripper present, for example in the form of control blocks or other elements that trigger the opening or closing process. Preferably, each conveyor has its own actuator. The conveyor tracks and the actuating device are designed and set up such that in a transfer area a transfer of the objects from the first grippers to the second grippers can take place.

According to the invention, there is at least one auxiliary conveyor with an auxiliary gripper moving along an auxiliary conveyor conveying track with the first grippers. The auxiliary grippers are able to grasp and fix the first object edges of individual or all held objects in the transfer area, so that the objects held by the auxiliary gripper do not fall out upon opening of the first gripper and are again conveyed therethrough after closure of the first gripper can be. According to the invention, the gripper conveyor track and the auxiliary conveyor conveyor track run in this way and the movements of the first grippers and the auxiliary grippers are controlled such that an object temporarily held by the auxiliary gripper and then returned to the first gripper at the end of the transfer area changed distance is held by its first object edge than when entering the transfer area. In this way, a position correction of the objects within the first gripper can be achieved. This is particularly advantageous in the case of differentiated conveying, in which, owing to the offset of the held edges, at least one product does not necessarily have the optimum position relative to the first gripper, e.g. too deep in the gripper is introduced.

In addition, a stabilizing device for stabilizing the objects held by the first grippers may be present. This is arranged in the conveying direction before the transfer area, wherein the objects in the actual transfer area, ie during the Handover process, already no longer be influenced by it. The stabilization device comprises moving stop elements with the first grippers, by means of which the second object edges are brought to the entrance of the transfer area in a position defined in the conveying direction and in the vertical direction. The stop elements stabilize the free edges in two dimensions and therefore reliably fix their position in the room.

The following steps are carried out according to the method: conveying the objects with the first gripper conveyor substantially suspended in the conveying direction, the first grippers holding the articles at a first edge of the article; Further conveying the articles through the second gripper conveyor, the second grippers holding a second article edge opposite the first article edge; Transferring the objects from the first grippers to the second grippers in the transfer area by opening the first grippers and closing the second grippers; intermediate fixing of the objects not to be dispensed by auxiliary grippers as long as the first grippers are opened for object dispensing, and re-transfer to the first gripper with an offset relative to the original position in the first gripper. In particular, an object held by the auxiliary gripper and returned to the first gripper at the end of the transfer region is kept at a different distance from its first article edge than when it enters the transfer region.

Optionally in addition: Stabilizing the objects held by the first grippers by means of a stabilizing device. According to the invention, the objects are stabilized in front of the transfer area by means of stop elements of the stabilization device with the first grippers be moved, that the second object edges are brought at the entrance of the transfer area in a defined in the conveying direction and in the vertical direction, the second object edges are released immediately before the transfer area or at the entrance of the transfer area again.

Transfer area is understood to mean the area in which the transfer process of the objects can take place from the first grippers to the second grippers, in particular because the grippers have approached each other so far that a controlled transfer is possible. In the transfer area, the object can preferably be influenced both by the first grippers and by the second grippers. A controlled transfer, in which the objects are gripped at any time, takes place, for example, by the second gripper or moving along with this auxiliary gripper closed and the first gripper are then opened.

The invention has the following advantages:

It is possible with simple means an intermediate fix the objects not to be delivered and at the same time a position correction in the return to the first gripper. This facilitates subsequent processes that rely on a defined position of the article within the gripper, especially with differentiated delivery in the incoming product stream. The auxiliary gripper conveyor can be realized mechanically very easily. For example, the auxiliary grippers can be moved along a circular conveyor track, for example by being attached to a rotary body. One to the main grapple exactly parallel track and thus a more complex management structure, such as a chain-channel system, is not necessary.

With optional additional stabilization device: Contrary to the prior art according to EP-A 1834911 The items are not kept during the entire transfer process, but only immediately before the transfer. The supporting device used for this purpose can be mechanically simple and space-saving. In the simplest case, these are merely moving stop or support elements which support and position the second object edges. They can be arranged in front of the transfer area below the first gripper. Laterally projecting support or guide structures are avoided. In a preferred embodiment of the invention, the support device has a substantially horizontally extending support surface, for example, formed by one or more conveyor belt, from which protrude with the first grippers moving stop elements, for example in the form of cams or projections.

The stop elements are moved, for example, along a stop element conveying track, which has a section running parallel to the first conveying track in front of the transfer area.

By releasing the second edges from the stop members at the entrance of the transfer area, they can be positioned very quickly in the open second grippers. This process is preferably assisted by the fact that the flexible objects are bent by the stabilization device. Preferably, the second object edge of the first object edge runs in the conveying direction. Outside the sphere of influence of the stabilization device, the objects again hang freely from the first gripper so that the second edge of the article releases quickly when released and thereby positioned in a defined manner relative to the second gripper. Preferably, it overcomes a certain height difference by the bending-relaxing and is thereby already positioned deep within the open second gripper mouth. The movement paths of the first and second grippers and the corresponding drives are preferably set up so that the grippers are moved in the transfer area in a coordinated manner, in particular synchronously.

To adapt to the object length, the distance of the stabilization device from the first gripper conveyor track is preferably variable. Likewise, preferably, the distance between the two gripper conveyor tracks can be varied from each other.

The inventive transfer device can be used flexibly. In an operating variant, the objects can be individually conveyed by the first gripper and transferred individually to the second gripper. In this case, the entire product flow is transferred or split from the first conveyor to the second conveyor. In a further operating variant, in each case two or more objects are conveyed as a group by the first grippers. The transfer to the second gripper takes place in a controlled manner so that all products of the group are handed over individually to successive second grippers and are conveyed on by them one by one. Alternatively, only individual products of a group are transferred to the second grippers. It is also possible that only every second (or nth) first gripper is opened and dispenses its products, while the remaining products are conveyed by the first conveyor. In this case, the product streams are split.

The invention can be used in particular for the transfer of groups of objects held in a common first gripper whose first edges offset against each other (differentiated promotion). For in particular in the case of objects having the same format, the second object edges can be separated from one another in a simple manner by sliding on a flat support surface of the stabilization device. The stop elements thereby position at least one of the second edges of the objects of a group. It has been found that it is not necessary to precisely position each of the second edges. In this case, for example, a divider may be inserted at the entrance of the transfer area between spaced second article edges of the articles held by a common first gripper, thereby facilitating transfer to different grippers.

To assist the transfer of the product, in particular with several products per gripper, one or more auxiliary conveyors may be present whose trajectory in the transfer area runs parallel to the path of the first or second gripper. The auxiliary conveyors are used, for example, to specifically transfer the products held together in a first gripper into successive second grippers or to hold one or more products in the first gripper despite opening the first gripper.

Fig. 1

eine Transfervorrichtung mit einem ersten Greiferförderer, einem zweiten Greiferförderer und einer vor dem Transferbereich angeordneten Stabilisierungsvorrichtung bei der Übergabe einzelner Gegenstände eines ersten Formats;

Fig. 2

die Transfervorrichtung gemäss Fig. 1 bei der Übergabe einzelner Gegenstände eines zweiten, grösseren Formats;

Fig. 3+4

die Transfervorrichtung gemäss Fig. 1 bei der durch einen Hilfsförderer unterstützten Übergabe von in Paaren geförderter Gegenstände mit einem ersten bzw. einem zweiten, grösseren Format;

Fig. 5

die Transfervorrichtung gemäss Fig. 1 bei der durch einen weiteren Hilfsförderer unterstützten Übergabe von in Paaren geförderter Gegenstände;

Fig. 6

die Transfervorrichtung gemäss Fig. 5 ohne eine Stabilisierungsvorrichtung;

Fig. 7

eine Variante der Transfervorrichtung gemäss Fig. 6 mit einer kreisförmigen Umlaufbahn der Hilfsgreifer;

Fig. 8

eine Variante der Transfervorrichtung gemäss Fig. 7, wobei die Hilfsgreifer zusätzliche Trennelemente aufweisen.

Examples of the invention are illustrated in the drawings and described below. It shows purely schematically:

Fig. 1

a transfer device having a first gripper conveyor, a second gripper conveyor and a stabilizer arranged in front of the transfer area when transferring individual articles of a first format;

Fig. 2

the transfer device according to Fig. 1 when handing over individual objects of a second, larger format;

Fig. 3 + 4

the transfer device according to Fig. 1 assisted by an auxiliary conveyor transfer of pairs of subsidized objects with a first or a second, larger format;

Fig. 5

the transfer device according to Fig. 1 in the case of transfer of items promoted in pairs, supported by another auxiliary conveyor;

Fig. 6

the transfer device according to Fig. 5 without a stabilizer device;

Fig. 7

a variant of the transfer device according to Fig. 6 with a circular orbit of the auxiliary gripper;

Fig. 8

a variant of the transfer device according to Fig. 7 wherein the auxiliary grippers have additional separating elements.

Fig. 1-5 show a transfer device 1 according to the invention in different operating variants.

The transfer device 1 comprises a first gripper conveyor 10 with first grippers 12, which along a guide member, for example, not shown here defined first gripper conveyor track U 1 are moved in a conveying direction F. The first gripper 12 are here conventional gripper with two approximately equally long gripper jaws 13, 14, which can assume an open position and a clamping position. The first grippers 12 are opened by a first actuating device 40, which is indicated here only schematically and may be formed, for example, as a control link, at an opening point S1. For interaction with the actuating device 40, the grippers 12 in a conventional manner controls, eg tax rolls, on. In the present case, the first gripper conveyor track U1 runs approximately horizontally in a first section U1 'and then rises obliquely in a second section U1'. The first grippers 12 convey articles 2 individually (FIG. Fig. 1 +2) or in pairs ( Fig. 3-5 ) coming from an upstream process. In this case, the objects are each held at their first edge 3, and the opposite second edges 4 have according to gravity down. In pairwise promotion ( Fig. 3-5 ) are the first edges offset from each other (differentiated promotion).

The transfer device 1 further comprises a second gripper conveyor 20 with second grippers 22, which are moved along a second gripper conveyor track U2. The second grippers 22 also have two gripper jaws 23, 24 whose position can be influenced relative to one another by means of a second actuating device 50, for example a control link. In the present case, the trailing gripper jaw 23 is extended relative to the leading gripper jaw 24. It makes it possible between two objects 2, which are held by the first gripper 12 and hang freely suspended, and divert them into different (adjacent) second gripper 22. The trailing gripper jaw 23 thus also acts as a separating element. The second gripper conveyor track U2 has a rising first section U2 'and an adjoining, substantially horizontal second section U2 ", which is located directly below the first gripper conveyor track U 1.

The two gripper conveyors 10, 20 may be part of a higher-level conveyor system. Their conveyor paths U1, U2 approach each other so far in an area, which is referred to below as the transfer area T, that an object 2 held by one of the grippers 12, 22 can be influenced by the other gripper. In this way, a controlled transfer of the objects 2 can take place. The conveyor tracks U1, U2 converge toward one another at the entrance E of the transfer area T with decreasing distance and then preferably run essentially parallel to one another. The transfer area T corresponds approximately to the overlap of the second parts U1 ", U2" of the first and second conveyor track U1, U2 up to the closing point S2 of the second gripper 22. The input E of the transfer area is, for example, the point at which the second gripper 22 or their elongated trailing legs 23 pierced the plane in which the product edges 4, 4 'were held by the stabilizing device 30 (plane of the support surface 34).

The transfer device 1 may further include first and second auxiliary conveyors 60, 70 each having auxiliary grippers 62, 72 moved along respective conveyor tracks U6, U7. These run at least in sections (in particular in the transfer area T) parallel to the conveyor tracks U1, U2 of the first and second gripper conveyors 10, 20. The function of the auxiliary conveyors 60, 70 will be described below with reference to FIG Fig. 3-5 explained. When transferring individual items (non-differentiated conveying), eg as in Fig. 1 +2, they are expendable.

Below the first section U1 'of the first conveyor track U1, ie in front of the entrance E of the transfer area T, according to the invention is the stabilization device 30. Here it comprises a driven conveyor belt 31 whose upper run forms a flat support surface 34. This is oriented parallel to the first section U1 'of the first conveyor track U 1. From the conveyor belt 31 are several stop elements 32 and are also driven. they run Therefore, along a stopper conveyor track U3, which is essentially defined by the conveyor belt 31. The conveyor belt 31 is deflected at the entrance E of the transfer area T, so that the stabilization device 30 ends there. The distance d 1 of the support surface 34 from the first conveyor track U 1 is preferably variable and set to be less than the length of the products in the vertical direction.

The distance d2 of the two gripper conveyors 10, 20 is preferably adjustable at least in the transfer area T. Particularly preferably, the stabilization device 30 is coupled to the second gripper conveyor 20, so that their distance from one another remains constant. In Fig. 2 the distances are opposite d1, d2 Fig. 1 enlarged, as longer products 2 are processed.

The following describes the function of the transfer device:

In Fig. 1 The first grippers 12 convey the objects 2 by holding them at the first edge 3. The second edge 4 rests on the support surface 34 of the stabilizing device 30 and abuts against the stop elements 32, so that the articles 2 are bent or slightly compressed (stretched) counter to the conveying direction F. The exact position of the second edges 4 in the conveying direction is determined by the position of the moving stop elements 32. The position in the vertical direction is defined by the position of the support surface 34 (height or distance from U1). The second grippers 22 approach from below the (imaginary) plane, which is defined by the support surface 34, and pierce them at the entrance E of the transfer area. The grippers 12, 22 and the stop elements 32 are synchronized so that the voltage applied to the stop element 32 second edge 4 when released by the stabilizing device 30, ie at the front end, by relaxing in the space between two trailing gripper jaws 23 adjacent second gripper 22 and in an open second gripper 22 jumps. Preferably, the long gripper jaw 23 is aligned with the front end of the stabilizer 30 when the abutment member 32 passes through the front end and thus releases the second edge 4. The second edge 4 is therefore positioned at the beginning of the transfer region T relatively low within a second gripper 22. As the two conveyor tracks U1, U2 continue to approach one another in a first section of the transfer area, the second edge 4 comes to rest on the bottom of the gripper jaw. The second gripper 22 can now be closed by a second section of the transfer area T by the actuator 50. Shortly before, the first gripper 12 is opened by the actuator 40. In order to achieve a particularly controlled transfer, the first gripper 12 can only be opened when the second gripper 22 has been closed. The extended trailing gripper jaws 23 of the second gripper 22 serve after the transfer as a support surface for the objects, which are then oriented in advance. Although the auxiliary grippers 62 of the lower auxiliary conveyor 60 are moved synchronously with the second grippers 22, but remain open and are therefore inoperative.

Fig. 2 corresponds to Fig. 1 with the difference that the product length and the distance d1 are increased. The second edges 4 are as at Fig. 1 to the stop elements 32 at. The trailing extended gripper legs 23 of the second gripper 22 are also aligned at the time of release of the second edges 4 with the support surface 34, so that the edge 4 is positioned deep within the second gripper 22. As in Fig. 1 the auxiliary conveyor 60 is inoperative.

3 and 4 show the pairwise conveying and transfer of objects 2, 2 '. The goal is the transfer of the product pairs 2, 2 'of every second first gripper 12 to two consecutive second gripper 22, wherein the other Product pairs 2, 2 'are further conveyed by the first gripper 12. For example, they can be transferred to a further conveyor in another correspondingly designed transfer area T. The actuating device 40 is correspondingly arranged so that only every second first gripper 12 is opened at the opening point S 1.

In the present case, in each case two objects 2, 2 'are held by a first gripper 12 such that their first edges 3, 3' are spaced apart from one another. The distance d1 between the first conveyor 10 and the stabilizing device 30 is set so that only the downwardly shifted object 3 'rests with its second edge 4' on the support surface 34 and on the stop element 32 and is bent therewith. This creates a gap 5 between the two objects 2, 2 '. Furthermore, the distance of the stopper members 32 in the case of Fig. 3 chosen so that only one object 2 'of each second pair of objects 2, 2' touches a stop element 32.

at Fig. 3 the extended gripper limb 23 penetrates into the gap 5 and thus separates the two objects 2, 2 '. The location of the gap 5 is well defined by the relative positions of the first gripper 12 and abutment member 32. The leading product 2 is therefore passed into the open gripper mouth of that second gripper 22, which is associated with the gripper arm 23. The trailing product 2 'is passed into the space between said gripper 22 and the trailing gripper 22 and in the open gripper mouth of the trailing gripper 22. The auxiliary grippers 62 serve to reliably transfer the objects 2, 2 'into the respective gripper jaw. A pair of products are therefore associated with the transfer of two second gripper, which are referred to in the following as leading or trailing gripper.

The auxiliary grippers 62 have two gripper parts 63, 64 which can assume a clamping and an open position relative to each other. The leading gripper part 63 has two support surfaces 63a, 63b arranged at an angle to each other. These form a stop for the second edge 4 'of the trailing product 2' of a pair of products. This edge 4 'runs against the stop and is clamped by closing the auxiliary gripper 62. The counter to the conveying direction oriented surface of the extended gripper jaw 23 of the leading gripper 22 acts as an additional support surface. The auxiliary gripper 62 is now moved within the transfer region T relative to the second grippers 22 so that its stop edge with the gripper jaw (bottom or local stop edge) of the trailing gripper 22 is aligned. For this purpose, the tracks U2, U6 of the second gripper 22 and the auxiliary gripper 62 and / or the auxiliary grippers cross a variable distance relative to their conveying member. The gripper 22 is closed at the end of the transfer area T and the auxiliary gripper 62 is opened again. In this way, the trailing product 2 'can be transferred very controlled in the trailing gripper 22.

The leading product 2 of a product pair is inserted directly into the open gripper mouth of the leading gripper 22. In the open gripper mouth are also both products 2, 2 'of a pair, which should not be handed over. Their lower edges 4, 4 ', however, are spaced from the clamping region of the second gripper 22. In addition, these products 2, 2 'by increasing the distance of the conveyor tracks U1, U2 towards the end of the transfer area and / or pivoting of the first gripper 12 relative to its conveyor track U1 pulled out of the gripper mouth and can be moved by the first gripper 12, which to remain closed.

at Fig. 4 the objects 2, 2 'are opposite to the case of Fig. 3 extends or the distance d1 is shortened, so that both second edges 4, 4 'of the staggered objects 2, 2' rest on the support surface 34. Each of the Trailing edge 4 'is on the stop element 32, while the leading edge 4 is located between two stop elements 32. The bearing surface 34 is here mechanically separated from the conveyor belt 31, on which the stop elements 32 are mounted, and stationary. The support surface 34 has a displaceable extension 34 ', which continues the support surface 34 and is movable in the direction of the support surface 34. Hereby, the point at which the second edges 4, 4 'are released, can be set exactly. It is possible, for example, to move this release point, which is defined by the front edge of the support surface 34 or the displaceable extension 34 ', from product to product. Here, the trailing products 2 'supported by the cam-like abutment element 32 are released directly by the cam 32 (retracted extension 34'), and the release point is moved forward for the other products 2 by displacing the extension 34 'in the conveying direction. As a result, the products 2 are guided longer and more controlled.

As in Fig. 3 The products 2, 2 'of each second pair are separated by retracting the extended gripper jaw 23 and transferred to adjacent second gripper 22. The role of the auxiliary gripper 62 is as with reference to FIG Fig. 3 described. The remaining pairs are also conveyed on after the transfer region T by the first grippers 12.

Fig. 5 shows a further example of the use of the transfer device 1. For dividing the flow of product pairs into two product streams, in which the products 2, 2 'are each held individually by a gripper 12, 22, here is another auxiliary conveyor 70 is used. This is arranged in the region of the first conveyor 10 so that its auxiliary gripper 72 can functionally support the first gripper 12 in the transfer area T. The rest of the construction is as in relation to Fig. 4 described. In particular, the distance d1 is chosen so that both second Edges 4, 4 'of the staggered objects 2, 2' rest on the support surface 34.

The sequence here is as follows: The pairs of objects 2, 2 'are conveyed by the first grippers 12 into the transfer region T. Before the transfer area T, the upper auxiliary grippers 72 approach from above the first grippers 12 and move in the transfer area T in synchronism with them. The corresponding gripper mouths are aligned with each other in a view on the plane of the drawing. The auxiliary gripper 72 hold when closing only one of the products 2, 2`. Here, the leading product 2 is held, which protrudes with its first edge 3 on the other product 2 '. The reverse case (trailing product is deeper in the gripper 12) is possible. When opening the first gripper 12, therefore, only the trailing product 2 'is released or generally the product that is less deeply inserted into the gripper 12. The first grippers 12 are closed again at the end of the transfer region T and the auxiliary grippers 72 are opened so that the leading products 2 are transported further by the first grippers 12. To open and close the upper auxiliary gripper 72 an actuating device not shown here is present.

The transfer of the trailing products 2 'to the second gripper 22 is supported by the lower auxiliary gripper 62. Before the transfer area T, the second grippers 22 and the auxiliary grippers 62 approach from below the plane in which the second edges 4, 4 'are located and pierce them at the entrance of the transfer area T. The second edge 4' is essentially defined by the here vertically oriented support surface 63a guided and then abuts on the other support surface 63b. By closing the auxiliary gripper 62, the edge 4 'is fixed and transferred in the further course of the transfer region T by relative movement of the second gripper 22 and the auxiliary gripper 62 in the gripper mouth of the second gripper 22. The second gripper 22 is closed and the auxiliary gripper 62 again open. The corresponding trajectories U2, U6 then separate again. The product 2 'is transported further by the second grippers 22. The leading product 2 need not be positioned accurately with respect to the second grippers 22 because it is not handed over to them. In the present case, first and second grippers 12, 22 are synchronized so that the leading product 2 is temporarily supported by the trailing surface of the long gripper limb 23. In contrast to Fig. 3 +4 the long gripper leg 23 does not separate the product pair here.

The trajectories U1, U7 are so and the movements of the grippers 72, 12 are controlled so that the following additional function is realized: The leading product 2 is delivered from the auxiliary gripper 72 to the first gripper 12, that it at the end of the transfer area T in is held at a smaller distance from its first edge 3 than when entering the transfer area T. The position of the product 2 relative to the first gripper 12 corresponds approximately to the position of the trailing product 2 'before it was discharged, and thus an "optimal" product position. The position of the product area clamped or held by the gripper 12 can therefore be changed by the temporary transfer to the auxiliary gripper 72. It can be achieved that the individually further conveyed objects 2 have a well-defined position relative to the gripper. For example, a defined distance of the gripped edge 3 to the bottom 12a of the gripper 12 (lowest point of the gripper) or to the outer ends 12b of the gripper limbs can be set. This differentiated promotion correction has advantages in subsequent processing steps where a particular product location relative to the gripper is required. Depending on the position of the products in the first gripper 12, the trailing product may also remain in the first gripper 12. It is also possible that by the auxiliary gripper no distance reduction, but a distance increase is realized. In any case, the interim transfer to the auxiliary gripper has two functions: Firstly, the object that is to be transported by the first gripper during the opening of the first gripper retained in the first gripper. Thus, the other object to be transported by the second gripper can be discharged. On the other hand, the position of the object to be transported within the first gripper can be corrected during the return to the first gripper.

It is obvious that the position correction by means of auxiliary grippers with differentiated conveyance of two or more products in a common gripper is independent of the stabilizing device described above and can therefore be used in any gripper-gripper transfer devices. This is schematically in Fig. 6 Shown: The transfer device according to Fig. 6 and their mode of operation Fig. 5 In each case one of the products 2, 2 'held by the first grippers 12 is transferred to second grippers 22 and the other is conveyed on by the first gripper 12. First and second grippers 12, 22 are synchronized so that in each case the longer leg of the second gripper 22 in the area between two pairs of products 2, 2 'punctures. For this purpose, no stabilization device is necessary because of the relatively large distances of the first gripper 12.

It can be seen that the auxiliary gripper orbit U7 is parallel to the orbit U 1 of the first gripper 12 over part of the transfer area. After the opening point of the first gripper 12, however, the orbits U1, U7 slightly apart, the gripper 12 and the auxiliary gripper 72, however, still aligned with each other transversely to the conveying direction. By diverging the orbits U1, U7 held by the auxiliary gripper 72 product 2 is offset relative to the first gripper 12. When closing the first gripper 12, it is therefore clamped in a different product area than before the transfer area, in the present case, this product area is closer to its edge 3 than before. This approximately corresponds to the clamping position of the dispensed product 2 'in the original formation.

Fig. 7 shows a variant of the device Fig. 6 , The auxiliary gripper conveyor 70 has a circular orbit U7. The circular path can be contrary to the circulation system according to Fig. 6 in which the orbit U7 is determined by suitably shaped guide means, for example a channel, realized very easily. The auxiliary grippers 72 may be attached to a rigid body and moved by rotation thereof about a horizontal axis A along the circular path U7. The orbit U7 intersects the orbit U 1 of the first gripper 12 in two places. In between are the points at which the first grippers 12 are opened and the auxiliary grippers 72 are closed (here denoted by S1) or the first grippers 12 are closed and the auxiliary grippers 72 are opened (designated S3). At these two reference points S1, S3 gripper 12 and auxiliary gripper 72 or their orbits U1, U7 have different distances b ', b from each other. Here the distance b 'of the grippers 12, 72 is defined as the distance of the pivot axes 15, 75 of the gripper jaws. It is zero at S1 and greater than zero at S3. The distance b is the distance of the orbits U1, U7. Since the products are hanging and the gripper jaws face downwards, only the component in the vertical direction is measured here. To the distance change Δb or Δb 'between the two points S1, S3 so the product 2 is moved by the transfer to the auxiliary gripper 72 and re-recording by the first gripper 12. The change in distance can be adjusted by selecting the shape and relative position of the orbits U1, U7 and the opening and closing points S1, S3. It is not mandatory that first gripper and auxiliary gripper are opened or closed at the same time; The auxiliary gripper can also be closed before opening the main gripper or opened after closing the main gripper.

The auxiliary grippers 72 are presently pivotable relative to their path U7. In this way, it can be achieved that they have a largely constant orientation in space in the transfer area T.

In order for auxiliary conveyor 70 and main conveyor 10 not to mechanically lock, auxiliary conveyor 70 may comprise two sub-auxiliary conveyors each disposed on different sides of main conveyor 10 and between which the main conveyor passes. An item not to be delivered is then held in the transfer area to the right and left of the main grippers of two auxiliary grippers.

Fig. 8 shows a variant of the transfer device Fig. 7 in which the auxiliary grippers 72 additionally have separating elements 80 or interact with such. The separating elements 80 serve to retract laterally from the first gripper 12 (eg to the right and left thereof) between two objects 2, 2 'of a group of objects conveyed jointly in the first gripper 12 and to expose selected ones of these objects to the influence of the auxiliary gripper 72, so that these can be gripped by the auxiliary gripper 72 and the other object or objects not. The use of such separating elements 80 is particularly advantageous when the objects 2, 2 'are arranged congruently in the gripper 12, in particular with congruent gripped edges 3, 3'.

In the present case, two objects 2, 2 'with congruent gripped edges 3, 3' are conveyed by a first gripper 12. At the entrance of the transfer region T, the separating element 80 pierces the objects 2, 2 'in the region of the gripped edges 3, 3'. For this purpose, the separating element 80 stands beyond the outer regions of the gripper limbs of the auxiliary grippers 72. In the further course of the orbit U7, the auxiliary gripper 72 are closed at S1. she only take one of the objects 2, here the leading one. This is thereby retained in the first gripper 12 when it opens. The other object 2 'is delivered to the second gripper 22. Subsequently, the first gripper 12 is closed again at S3 and the auxiliary gripper 72 is opened. As in Fig. 7 the position of the conveyed article 2 in the first gripper 12 is changed.

The solution described above with the separating elements 80 can also be used independently of a positional correction, i. the conveyed objects 2 can be taken in the same position again from the first gripper 12, they originally had. The separating elements 80 may be an integral part of the auxiliary gripper 72. Their position or orientation relative to the legs of the auxiliary gripper 72 can preferably be controlled. It is also possible that one of the legs of the auxiliary grippers 72 performs the function of the separating element, i. is controlled so that it enters between the products 2, 2 '. However, the separating elements 80 can also be fastened to a separate drive system and moved only in the transfer area in synchronism with the auxiliary grippers 72 or the main grippers 12. You drive as here between the gripped edges 3, 3 'a. Alternatively, the dividers 80 are inserted from the side (not shown here). The dividers 80 may be controlled to lift the overlapping objects apart so that the auxiliary gripper 72 can more easily grasp the selected items.

The device variant with the separating elements therefore consists in its most general form of a first gripper conveyor, an auxiliary conveyor and a plurality of separating elements, which are moved along a closed orbit. This may be identical to the orbit of the auxiliary gripper, but may also differ. The separating elements are controlled so that in the transfer area between two objects one of the first Retracting gripped group of objects, so that selected these objects can be gripped by the auxiliary gripper. Optionally, the above-described positional correction by the auxiliary gripper and the stabilization of the freely suspended object edges.

Claims (15)

1. A device for the transfer of flexible, two-dimensional objects (2, 2'), in particular printed products, between two conveyors, comprising a first gripper conveyor (10) with first grippers (12) which are moved along a first gripper conveying path (U1) for the essentially hanging transport of the objects (2, 2') in a conveying direction (F) by way of gripping a first object edge (3, 3'), a second gripper conveyor (20) with second grippers (22) moved along a second gripper conveying path (U2) for receiving the objects (2, 2') by way of gripping a second object edge (4, 4') which lies opposite the first object edge (3, 3'), at least one actuation device (40, 50) for opening and closing the first and second grippers (12, 22) in a manner such that in a transfer region (T), a transfer of the objects (2, 2') from the first grippers (12) to the second grippers (22) may take place, and at least one auxiliary conveyor (70) with auxiliary grippers (72) which are co-moved with the first grippers (12) along an auxiliary conveyor conveying path (U7) and which in the transfer region (T) are capable of gripping the first object edges (3, 3') and fixing them, characterised in that the gripper conveying path (U1) and the auxiliary conveying path (U7) run and the movements of the first grippers (12) and of the auxiliary grippers (72) are controlled, such that an object (2, 2') which is held by the auxiliary gripper (72) and is released again to the first gripper (12), at the end of the transfer region (T), is held at a changed distance to its first object edge (3, 3') compared to distance when entering into the transfer region (T).
2. A device according to claim 1, characterised in that the first grippers (12) are opened at an opening location (S1) and are closed at a closure location (S3) and that the auxiliary grippers (72) are closed in front of or at the opening location (S1), and are opened again at or after the closure location (S3).
3. A device according to claim 2, characterised in that the distances (b) between the first gripper conveying path (U1) and the auxiliary conveyor conveying path (U7) are different from one another at the opening location (S1) and the closure location (S3).
4. A device according to one of the preceding claims, characterised in that the auxiliary conveyor (70) has a circular auxiliary conveyor conveying path (U7), in particular by way of the auxiliary grippers (72) being arranged on a rigid rotation body.
5. A device according to one of the preceding claims, characterised in that the auxiliary conveyor (70) comprises two auxiliary part-conveyors (70) which in each case are arranged on different sides of the first gripper conveyor (10), wherein an object (2, 2') which is not to be released is held in the transfer region by in each case two auxiliary grippers (72).
6. A device according to one of the preceding claims, characterised in that the distance (d2) of the second gripper conveying path (U2) to the first gripper conveying path (U1) is variable for adapting to the object length.
7. A device according to one of the preceding claims, characterised in that the first and second gripper conveying path (U1, U2) are converging in front of the transfer region (T) and are orientated essentially parallel to one another in the transfer region (T).
8. A device according to one of the preceding claims, characterised by at least one second auxiliary conveyor (60) with auxiliary grippers (62) which are co-moved with the second grippers (22) along a second auxiliary conveying path (U6) and which in the transfer region (T) are capable of gripping the second object edges (4, 4') and fixing them.
9. A device according to one of the preceding claims, characterised by at least one separating element (80) which, in the transfer region, is capable of moving in between two objects (2, 2') of a group of objects which is commonly held by the first grippers (12), such that selected ones of these objects may be gripped by the auxiliary grippers (72) which are co-moved with the first grippers (12).
10. A method for the transfer of flexible, two-dimensional objects (2, 2'), in particular printed products, between two conveyors, with the following steps:

    - conveying the objects (2, 2') with a first gripper conveyor (10) which comprises first grippers (12), along a first gripper conveying path (U1) in an essentially hanging manner in a conveying direction (F), wherein the first grippers (12) hold the objects (2, 2') at a first object edge (3, 3'), wherein the first grippers (12) in each case convey at least two objects (2, 2'),

    - further conveying the transferred objects (2, 2') by way of a second gripper conveyor (20) which comprises second grippers (22) which are moved along a second gripper conveying path (U2), wherein the second grippers (22) hold a second object edge (4, 4') which lies opposite the first object edge (3, 3'),

    - transferring at least one of the objects (2, 2') held by the first grippers (12), to the second grippers (22) in a transfer region (T), by way of opening the first grippers (12) and closing the second grippers (22), wherein at least one further one of the objects (2, 2') is conveyed further by the first grippers (12);

    - wherein the first object edge (3, 3') of the at least one further one of the objects (2, 2') is fixed in the transfer region (T) by way of auxiliary grippers (62, 72) co-moved synchronously with the first and/or second grippers (12, 22), and are subsequently released again,

    characterised in that an object (2, 2') which is held by the auxiliary gripper (72) and released again to the first gripper (12), at the end of the transfer region (T) is held at a changed distance to its first object edge (3, 3') compared to the entry into the transfer region (T).
11. A method according to claim 10, characterised in that the first grippers (12) are opened at an opening location (S1) and are closed at a closure location (S3) and that the auxiliary grippers (72) are closed before or at the opening location (S1) and are opened again at or after the closure location (S3).
12. A method according to claim 10 or 11, characterised in that the auxiliary grippers (72) are moved along a circular auxiliary conveying path (U7).
13. A method according to one of the claims 10-12, characterised in that the first grippers (12) in each case convey at least two objects (2, 2'), of which in the transfer region (T) at least one is transferred to the second grippers (22) and at least one further one is conveyed further by the first grippers (12).
14. A method according to claim 13, characterised in that the at least two objects (2, 2') are held by the first grippers (12) such that their first object edges (3, 3') are distanced to one another.
15. A method according to claim 13 or 14, characterised in that a separating element (63) at the entry of the transfer region (T) moves in between the second object edges (4, 4') of the objects (2, 2') which are distanced to one another, said objects being held by a common first gripper (12), and that the objects (2, 2') are conveyed further in different grippers (12, 22).

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