Handling device and method for picking up sheet-like articles

Abstract

A handling device (1) for separating sheet-like articles of a first type (4) and of a second type (5), lying alternately on one another but not fully congruent, comprises at least one main gripper (7) provided for gripping one of the sheet-like articles of the first type (4) and at least one auxiliary gripper (12) provided for additionally gripping one of the sheet-like articles of the second type (5), wherein the different grippers (7, 12) are held on a common support structure (6, 8) and are movable relative to each other in a vertical direction such that, as the different sheet-like articles (4, 5) are picked up, an increasing distance can be produced between these articles (4, 5).

Description

[0001] Handling device and method for lifting flat objects

[0002] The invention relates to a handling device suitable for separating flat objects of different types lying on top of one another, wherein an object of the first type and an object of the second type are arranged alternately in a stack. Furthermore, the invention relates to a method for lifting stacked flat objects, which provide an alternating layer sequence.

[0003] EP 4 002 533 A1 discloses a device and a method for stacking fuel cell components. It is assumed that the cell components from which fuel cells are to be manufactured are delivered individually. The cell components, present individually, i.e., in a spaced-apart arrangement, are fed to a vertical stacker. The vertical stacker comprises a vertical magazine that allows the cell components held therein to be moved up and down. The vertical stacker is designed to dispense cell components individually by downward movements in a vertical direction. Overall, the device according to EP 4 002 533 A1 is designed for the large-scale production of fuel cells.

[0004] DE 20 2006 021 243 U1 discloses a vacuum gripper with multiple suction points. The suction points communicate with a controller of the vacuum gripping system. The suction point has a sensor and a valve, with the sensor located in a vacuum line. According to DE 20 2006 021 243 U1, each suction point is equipped with its own vacuum generator.

[0005] DE 10 2007 025 098 A1 describes a controlled device for the contactless separation, centering, gripping, and handling of flat, disc-like objects. Part of this device is a compressed air supply, whereby timed compressed air streams impinging on a stack are intended to separate the flat, disc-like objects lying one above the other. The device according to DE 10 2007 025 098 A1 is intended to be used, among other things, for handling semiconductor wafers and solar cells.

[0006] Further devices for handling objects which in particular have a flat shape are known from the documents DE 10 2012 200 535 A1, DE 10 2017 107 215 A1, DE 10 2013 201 247 B4 and DE 10 2015 119 321 A1.

[0007] The invention is based on the object of further developing the handling of flat components, which are intended in particular for the assembly of fuel cell stacks, compared to the cited prior art, whereby a particularly favorable ratio between equipment expenditure and process reliability is sought.

[0008] This object is achieved according to the invention by a handling device having the features of claim 1. The object is also achieved by a method with which flat objects are lifted from a stack, according to claim 10. Embodiments and advantages of the invention explained below in connection with the method also apply mutatis mutandis to the handling device designed as a separating device, and vice versa.

[0009] It is assumed that there is a stack made up of flat objects of the first type and flat objects of the second type, with the different objects lying alternately on top of one another. In this case, an object of the first type does not completely cover the object of the second type underneath. This means that the various objects are not arranged completely congruently in the stack. A deviation from a completely congruent arrangement can occur in particular if the object of the first type has perforations so that - with the first object as the uppermost layer of the entire stack - flat sections of the second object corresponding to the dimensions of the perforations are visible from above. Alternatively, the second object lying underneath can protrude laterally beyond the first object.In any case, the various objects are cut and arranged in such a way that it is in principle possible to lift them simultaneously, in particular by means of negative pressure.

[0010] For this purpose, the handling device has at least one main gripper and at least one auxiliary gripper. The main gripper is provided for lifting the flat object of the first type. For example, the main gripper is designed as a vacuum gripper designed to suction the flat object of the first type. Alternatively, the main gripper can be based on any other physical principle. For example, the main gripper is an adhesion gripper, a flow gripper, or a magnetic gripper. Correspondingly, the auxiliary gripper can also be a vacuum gripper or another gripper suitable for lifting flat objects.

[0011] Where reference is made below to a main vacuum gripper or an auxiliary vacuum gripper, the corresponding statements apply analogously to other types of main gripper or auxiliary gripper. Simultaneously with the lifting of the flat object of the first type by the main gripper, the at least one auxiliary gripper, in particular the auxiliary vacuum gripper, is always capable of lifting the underlying flat object of the second type. Typically, the area-related weight of the object of the second type is lower than the area-related weight of the object of the first type.

[0012] The various grippers, in particular vacuum grippers, are held on a common support structure and can be moved vertically relative to one another so that an increasing distance can be created between the various flat objects when lifting the said objects.

[0013] Optionally, there is an outlet opening, or a plurality of such outlet openings, connected to the auxiliary vacuum gripper for introducing an air flow between the various flat objects. Injecting air into the gap formed between the two flat objects after they have been lifted off contributes to the permanent separation of the flat object below from the flat object above. The outlet opening provided for this purpose is located, for example, on a vertical tube, to the lower end of which the auxiliary vacuum gripper is attached.

[0014] According to one possible embodiment, the auxiliary gripper, particularly in the form of an auxiliary vacuum gripper, is spring-loaded relative to the main vacuum gripper or other main gripper in order to maximize the vertical distance between the various grippers, i.e., to enlarge the aforementioned gap. This also applies in cases where the handling device has a plurality of auxiliary vacuum grippers, for example, two auxiliary vacuum grippers that are relatively small compared to the main gripper and are arranged on diametrically opposite sides next to the main gripper. Compression springs in the form of helical springs, for example, are suitable for spring loading. As an alternative to compression springs, which apply a force to the auxiliary vacuum grippers, a tension spring can also be used, which acts on the main gripper.In all cases, the final repulsion of the second flat object located below can be assisted by a downward air stream emanating from the auxiliary vacuum gripper.

[0015] According to a possible development, there is a container which has a shearing plate designed to engage in the space formed between the various flat objects and, when the flat objects are advanced, to force the separation of the lower of the two flat objects from the auxiliary vacuum gripper. The mechanical action of the shearing plate, i.e., the feeding of the flat object detached by the auxiliary vacuum gripper to the container, is optionally supplemented by a blower arranged in the container or connected to the container, i.e., a suction device. The handling device can be used in particular for lifting stacked fuel cell components. The flat object of the first type can in particular be a bipolar plate or a membrane-electrode arrangement. The object of the second type can, in such cases, be an intermediate layer to be disposed of.

[0016] The method for lifting flat objects of different types in stack form assumes that objects lying alternately on top of one another in a stack are arranged in such a way that each flat object of the first type does not completely cover the flat object of the second type lying underneath it and generally comprises the following steps:

[0017] - Simultaneous contacting of a flat object of the first type with a main gripper, for example in the form of a vacuum or flow gripper, and contacting of a flat object of the second type with at least one auxiliary gripper, wherein the auxiliary gripper can also be designed, for example, as a vacuum gripper or as a flow gripper,

[0018] - vertical removal of the main gripper together with the flat object of the first type from the arrangement of auxiliary grippers or auxiliary grippers and the object of the second type,

[0019] - introducing blown air into the gap formed between the different flat objects and thus removing the flat object of the second type from the at least one auxiliary gripper,

[0020] - Further conveyance of the flat object of the first type held on the main gripper when the object of the second type is released by the auxiliary gripper.

[0021] The flat object of the second type is typically a layer of flexible material. The flat object of the first type can be made of flexible or rigid material. The detachment of the flexible layer and feeding of the upper object of the first type to an assembly device not part of the handling device can be carried out at high cycle times, down to cycle times of less than 1 s. An exemplary embodiment of the invention is explained in more detail below with reference to a drawing. These schematic views show:

[0022] Fig. 1 shows a handling device for lifting various flat objects from a stack,

[0023] Fig. 2 the handling device including a container for receiving layers of the stack of flat objects to be disposed of,

[0024] Fig. 3 Components of the arrangement according to Fig. 2 in plan view.

[0025] A handling device, designated overall by reference numeral 1, comprises a gripping device 2 and is used in the assembly of fuel cell stacks. The gripping device 2 is designed to lift flat objects 4, 5 from a plate arrangement 3, generally referred to as a stack. Within the stack 3, the various objects 4, 5 are stacked alternately. A maximum of one pair of objects 4, 5 is shown in the figures.

[0026] The gripping device 2 includes a vertically adjustable central support 6, from which a crossbeam 8 extends. The central support 6 and the crossbeam 8 are components of a support structure. A main gripper 7 is suspended from the central support 6. In the present case, the main gripper 7 is a flow gripper. Alternatively, the main gripper 7 could be designed as a vacuum gripper, for example. Two gripping devices are also connected to the central support 6 via the crossbeam 8, which are collectively referred to as side grippers 9, 10 and are arranged diametrically opposite one another next to the main gripper 7. Each side gripper 9, 10 is assigned a vertical tube 11, which is spaced parallel to the central support 6. Vertical tubes 11 arranged at the rear in the arrangement according to Fig. 1 are not visible in this illustration.Auxiliary grippers 12, in this case designed as vacuum grippers, are suspended from the vertical tubes 11. The vertical tube 11 is longitudinally movable relative to the central support 6, so that the auxiliary vacuum grippers 12 can be displaced vertically relative to the main gripper 7. Figure 1 shows, as an example, compressed air fittings 13 to which the auxiliary vacuum grippers 12 are connected. Springs 14 exert a downward pressure force in the vertical direction on the auxiliary vacuum grippers 12.

[0027] In the lower area of ​​the vertical tubes 11, i.e., slightly above the auxiliary vacuum grippers 12, there are outlet openings 15 that allow the discharge of an air stream LS essentially in a horizontal direction. Furthermore, the auxiliary vacuum grippers 12 are also capable of expelling an air stream LS, in this case in a vertical downward direction. Air sucked in by the vacuum grippers 7, 12 is generally referred to as intake air AL.

[0028] As long as the plate arrangement 3 is not yet being processed, the various flat objects 4, 5 lie directly on top of one another. The object 4 located on top in the arrangements according to Figures 1 to 3, which is generally also referred to as the main plate or upper layer, is in the exemplary embodiment a bipolar plate that is to be assembled together with other components to form a fuel cell stack. The main plate 4 could also be a membrane electrode assembly, which is also intended for installation in a fuel cell stack. In contrast to the upper layer 4, the second flat object 5, which is also referred to as the intermediate layer, merely serves the purpose of separating the main plates 4 from one another within the plate arrangement 3 and is not intended for installation in the fuel cell stack. As indicated in the figures, the intermediate layer 5 is significantly thinner than the upper layer 4.In addition, the intermediate layer 5 is significantly more flexible than the main plate 4.

[0029] When lifting the main plates 4 from the plate assembly 3, care must be taken to ensure that the intermediate layer 5 is reliably removed before installing the main plate 4 into the fuel cell stack. First, the various flat objects 4, 5 are selectively lifted together from the plate assembly 3. When the gripping device 2 is applied to the plate assembly 3, the auxiliary vacuum grippers 12 encounter recesses in the main plate 4, allowing them to directly contact the intermediate layer 5 and lift it. At the same time, the main gripper 7 contacts a surface area of ​​the main plate 4 in which there are no recesses.

[0030] Starting from this state, in which the main plate 4 as well as the intermediate layer 5 are attracted to the gripping device 2 by negative pressure, the central support 6 together with the main gripper 7 is raised, resulting in the state sketched in Figure 1. The vertical tubes 11 together with the auxiliary vacuum grippers 12 are pressed downwards by the springs 14, which means that the intermediate layer 5 is released from the main plate 4. The outlet openings 15 are located, as can be seen from Figure 1, in the gap formed between the various flat objects 4, 5. In order to separate the intermediate layer 5 from the auxiliary vacuum grippers 12, compressed air is expelled from the outlet openings 15 as well as from the auxiliary vacuum grippers 12.

[0031] For the disposal of the intermediate layer 5, a container 16 is available, which is visible in Figures 2 and 3. Container walls are designated by 17. In addition to the walls 17, the container 16 has a shear plate 18 in its upper region. If the arrangement of the two flat objects 4, 5 is moved in the conveying direction FR, as indicated in Figures 2 and 3, the shear plate 18 engages in the gap between the various objects 4, 5. The shear plate 18 thus scrapes off the intermediate layer 5, provided the intermediate layer 5 does not fall into the container 16 by itself. The feeding of the intermediate layer 5 to the container 16 is assisted in the exemplary embodiment by a suction device 19. List of reference symbols

[0032] 1 handling device

[0033] 2 gripping device

[0034] 3 plate arrangement, stack

[0035] 4 flat object of the first type, main plate, upper layer

[0036] 5 flat object of the second type, intermediate layer

[0037] 6 center support

[0038] 7 main grippers

[0039] 8 crossbeams

[0040] 9 side grippers

[0041] 10 side grippers

[0042] 11 Vertical pipe

[0043] 12 auxiliary grippers

[0044] 13 Compressed air fitting

[0045] 14 spring

[0046] 15 Outlet opening

[0047] 16 containers

[0048] 17 Container wall

[0049] 18 shear plate

[0050] 19 Suction device

[0051] AL intake air

[0052] FR conveying direction

[0053] LS airflow

Claims

Patent claims 1. Handling device (1) for separating flat, not completely congruent objects of the first type (4) and the second type (5) lying alternately on top of one another, with at least one main gripper (7) provided for gripping one of the flat objects of the first type (4) and at least one auxiliary gripper (12) provided for additionally gripping one of the flat objects of the second type (5), wherein the various grippers (7, 12) are held on a common support structure (6, 8) and can be displaced relative to one another in the vertical direction, so that when the various flat objects (4, 5) are lifted off, an increasing distance can be created between these objects (4, 5).

2. Handling device (1) according to claim 1, characterized in that the auxiliary gripper (12) is spring-loaded relative to the main gripper (7) in order to maximize the vertical distance between the various grippers (7, 12).

3. Handling device (1) according to claim 1 or 2, characterized in that the auxiliary gripper (12) is provided with an outflow opening (15) which serves to introduce an air flow between the various flat objects (4, 5).

4. Handling device (1) according to one of claims 1 to 3, characterized in that at least two auxiliary grippers (12) are arranged on diametrically opposite sides next to the main gripper (7).

5. Handling device (1) according to claim 4, characterized in that the auxiliary grippers (12) are smaller than the main gripper (7).

6. Handling device (1) according to one of claims 3 to 5, characterized in that the at least one auxiliary gripper (12) is also designed to expel a downwardly directed air stream.

7. Handling device (1) according to one of claims 1 to 6, characterized by a container (16) which has a shear plate (18) which is intended to engage in an intermediate space formed between the various flat objects (4, 5) and, when the flat objects (4, 5) to force the separation of the lower of the two flat objects (5) from the auxiliary gripper (12).

8. Use of a handling device (1) according to claim 1 for lifting stacked fuel cell components (4).

9. Use according to claim 8, characterized in that the handling device (1) is used for separating fuel cell components (4) which are selected from the group of components comprising bipolar plates and membrane electrode assemblies and which are to be lifted with the main gripper (7), whereas the flat objects (5) to be lifted with the auxiliary gripper (12) are intermediate layers which are not intended for installation in a fuel cell stack.

10. Method for lifting flat objects (4, 5) of different types in stack form, comprising the following steps: - providing a stack of flat objects (4, 5), wherein a flat object of the first type (4) does not completely cover a flat object of the second type (5), - simultaneous contacting of a flat object of the first type (4) with a main gripper (7) and contacting of a flat object of the second type (5) with at least one auxiliary gripper (12), - vertical removal of the main gripper (7) together with the flat object of the first type (4) from the arrangement of the auxiliary gripper (12) and the object of the second type (5), - introduction of blown air into the gap formed between the various flat objects (4, 5), - Further conveyance of the flat object of the first type (4) held on the main gripper (7) when the object of the second type (5) is detached from the auxiliary gripper (12).

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