Device for holding planar workpiece and system and method for transporting planar workpiece through tank of plant for wet chemical treatment

Abstract

The invention relates to a conveying device for conveying planar workpieces (4; 32) for the workpiece (4; 32), comprising a plurality of workpiece holding devices (1; 29). Each workpiece holding device (1; 29) comprises: at least one clamping device (2, 3; 30, 31) for clamping the workpiece (4; 32) in the plane; and a structure, seen perpendicular to the plane and in the absence of the workpiece, surrounding an area (8) of the plane on at least three sides. The structure comprises a first part (9; 34) and the second component (10; 35) arranged on first and second sides of the region (8) and having respective longitudinal axes extending in a first direction (z) parallel to the plane. The system further comprises means for transporting the workpiece holding device (1; 1 ') in a second direction (x) parallel to the plane and transverse to the first direction (z). 29) of the conveyor. Seen in the second direction (x), the workpiece holding device (1; 9) of a first one of the first parts (9; 34) and the second part (10; 35) and in the second direction (x) the workpiece holding device (1; 29) relative to the longitudinal axis of the trailing one of the first part (9) and the second part (10) of the next of the workpiece holding devices (1; 29) is offset in an opposite direction perpendicular to said plane such that the first workpiece holding device (1; 29) of the guide element (9, 10; 34, 35) and the next workpiece holding device (1; 29) at least partially face each other.

Description

Technical Field

[0001] The invention relates to a device for holding a planar workpiece in a tank of an apparatus for wet-chemical treatment of said workpiece, said device comprising:

[0002] at least one clamping device for holding the workpiece in a plane;

[0003] a structure which, as seen perpendicularly to said plane and in the absence of said workpiece, surrounds, on at least three sides, an area of ​​said plane,

[0004] wherein the structure comprises a first component and a second component arranged on a first and a second side of the region and having respective longitudinal axes extending in a first direction parallel to the plane, and

[0005] wherein the structure comprises an interconnection member interconnecting the first member and the second member on a third side of the region; and

[0006] At least one member for attaching the interconnection member to a conveyor for transporting the device in a second direction parallel to the plane and transverse to the first direction.

[0007] The invention also relates to a system for conveying planar workpieces through a slot of a device for wet-chemical treatment of said workpieces,

[0008] The system comprises a plurality of workpiece holding devices, each of which comprises:

[0009] at least one clamping device for holding the workpiece in a plane; and

[0010] a structure which, as seen perpendicularly to said plane and in the absence of said workpiece, surrounds an area of ​​said plane on at least three sides,

[0011] wherein the structure comprises a first component and a second component arranged on a first and a second side of the region and having respective longitudinal axes extending in a first direction parallel to the plane, and

[0012] The system further comprises a conveyor for transporting the workpiece holding device in a second direction parallel to the plane and transverse to the first direction.

[0013] The invention also relates to a device for the wet-chemical processing of planar workpieces.

[0014] The invention also relates to a method for conveying flat workpieces through a slot of a device for wet-chemical treatment of said workpieces,

[0015] The workpiece is mounted on a corresponding workpiece holding device, each workpiece holding device comprising:

[0016] at least one clamping device for holding the workpiece in a plane; and

[0017] a structure which, as seen perpendicularly to said plane and in the absence of said workpiece, surrounds an area of ​​said plane on at least three sides,

[0018] wherein the structure comprises a first component and a second component which are arranged on a first and a second side of the region and have respective longitudinal axes extending in a first direction parallel to the plane,

[0019] The workpiece holding device is transported in a second direction parallel to the plane and transverse to the first direction, so that a rear edge of the first workpiece is separated from a leading edge of the second workpiece by a gap. Background Art

[0020] CN 209428629 U discloses a frame-type bracket for electroplating machines, which is particularly suitable for carrier substrates (printed circuit boards) that pass through the plating machine for processing purposes. The bracket includes a horizontal pull rod when in use, a relative pull rod parallel to the pull rod, a right rod that is vertical (and therefore perpendicular to the pull rod and the bottom pull rod) when in use, and a left rod that is opposite to the right rod and parallel to the right rod. The top pull rod, the bottom pull rod, the left rod and the right rod are connected to each other and to the bottom connector through two top connectors to form a rectangular frame-like structure. A plurality of top clamps are mounted on the top pull rod for releasably grasping the top edge of the workpiece. A plurality of bottom clamps are mounted on the bottom pull rod for releasably grasping the bottom edge of the workpiece. One of the top connectors is fixedly engaged (e.g., by welding) at or near the upper longitudinal end of the left rod. Similarly, another of the top connectors is fixedly engaged at or near the upper longitudinal end of the right rod. Each top connector has a rectangular groove or groove for receiving the corresponding longitudinal end of the top pull rod. The bottom connector is covered with an electrically insulating material. Both the left rod and the right rod are cylindrical and conductive. Since the right and left rods are conductive, electroplating will be performed on the right and left rods. This will reduce the amount of metal plated on the left and right edges of the workpiece and thus achieve better plating uniformity. Compared with vertical rods with rectangular cross-sections, cylindrical left and right rods will not induce local current during plating. The left and right rods are shown as being adjacent to the left and right edges of the workpiece, but not exactly in the plane of the workpiece. Therefore, the effects obtained by the rods are not the same for the two surfaces of the workpiece. In addition, processing uniformity is only obtained in electrochemical processing, and the rods must be de-plated or replaced and the position of the rods requires a certain interval between the continuous workpieces that are transported through the plating tank installed in the bracket. Summary of the invention

[0021] The object of the present invention is to provide a device, a system, an apparatus and a method of the type mentioned in the opening paragraph above, which allow surface treatment of workpieces conveyed in close succession so that a relatively uniform surface treatment is achieved at the leading and trailing edges of the workpieces on both sides of the workpieces.

[0022] According to a first aspect, this object is achieved by a device according to the invention, which is characterized in that the longitudinal axis is offset relative to the plane in opposite directions perpendicular to the plane.

[0023] Since the longitudinal axis is offset relative to the plane in opposite directions perpendicular to the plane, the two holding devices can be transported closely and continuously in the second direction, with only a small (empty) gap between the leading edge of the workpiece held by the upstream device and the trailing edge of the workpiece held by the downstream device. The leading one of the first and second parts of the upstream holding device faces the trailing one of the first and second parts of the downstream holding device across the gap. This provides a shielding effect because the liquid in the groove cannot flow through the gap in large quantities. Therefore, excessive processing, such as material deposition or removal at the area of ​​the main surface of the workpiece close to the edge, is avoided. If the liquid is an electrolyte and the treatment is an electrochemical treatment, there is less conductive liquid near the edge area. The electric field lines are therefore deflected from the edge area.

[0024] The offset distance may be selected to optimize uniformity. In an embodiment, the offset distance may be adjustable.

[0025] The device comprises at least one clamping device for holding the workpiece in a plane. Typically there may be more than one clamping device. They may be arranged along one or more edges of the area. By their configuration and position, the clamping device defines the plane, so that the position and orientation of the plane can be determined even in the absence of the workpiece. The clamping device is typically arranged to grip the workpiece at one or more edges of the workpiece so that the arms of the clamps of the clamping device engage the major surface of the workpiece near one or more edges of the workpiece. In the case of a quadrilateral workpiece, the clamping device may be arranged to engage the workpiece along only one or two edges of the workpiece. This may include edges proximal to the interconnecting members, and (for example, optionally) opposite edges.

[0026] The structure included in the device surrounds an area of ​​the plane on at least three sides, as seen perpendicular to the plane. The area will typically not correspond exactly to the complete area of ​​the plane occupied by the workpiece. Viewing the plane in a direction perpendicular to the plane, in the absence of the workpiece, the structure appears to surround the area on at least three sides. However, it should be noted that the structure will typically not lie in the plane. In particular, the first component and the second component are offset relative to the plane so that they may not, and typically do not, span the plane.

[0027] The structure comprises a first component and a second component, which are arranged on a first and a second side of the area and have respective longitudinal axes extending in a first direction parallel to the plane. Here, the first and the second side refer to the appearance of the plane when an observer looks at the plane in a direction perpendicular to the plane and in the absence of a workpiece. In the presence of a workpiece, only one of the first component and the second component is usually fully visible, because the other is at least partially behind the workpiece. The first component and the second component usually have corresponding shapes and sizes to achieve better uniformity of the flow field passing through the two surfaces of the workpiece.

[0028] The structure comprises an interconnection member interconnecting the first and second members on a third side of the area. This interconnection member need not be a single element, but may be an assembly. The interconnection member may be attached to the conveyor by at least one member for attaching the interconnection member to the conveyor. This attachment member may be a hook or an arm. Thus, in use, the interconnection member interconnecting the first and second members on the third side of the area will typically be the upper interconnection member. The third side will be the side above the area. The device may be considered as a hanger for the workpiece.

[0029] At least one component is provided to attach the interconnected components to a conveyor for transporting the device in a second direction parallel to the plane and transverse to the first direction. The conveyor may include, for example, a chain or belt, or a shuttle on a rail or track. Thus, the direction of movement is such that one of the first component and the second component is located at the leading edge of the workpiece and the other is located at the trailing edge of the workpiece. Due to the offset of the longitudinal axis relative to the plane in the opposite direction perpendicular to the plane, as opposed to offset in the same direction, the workpiece can be installed and removed from one side when only one of the first component and the second component is in the way. This may involve moving the workpiece along a trajectory including a pivot about an axis parallel to the longitudinal axis of the first component and the second component. A shielding effect due to the leading of the first and second components of the upstream holding device facing the trailing of the first and second components of the downstream holding device across the gap between the edges of the workpiece can also be obtained by providing a holding device in which the longitudinal axes of the first and second components are offset in the same direction. In this case, every other device will turn to face the opposite direction of the adjacent holding device. However, every other holding device will then cause the first part and the second part to block the parts from being removed or installed. Therefore, the workpiece cannot be installed or removed from the same side of each device. In contrast, here, at least one section between any attachment points of the parts of the first part and the second part interconnecting each of the first part and the second part faces empty space in the direction of the plane. This empty space can be used to manipulate the workpiece.

[0030] In an embodiment, the interconnection member is releasably connected to at least one of the first and second members by respective fixing means, and the engagement position between the fixing means and the one of the first and second members concerned is variable in the first direction.

[0031] This provides a simple way to adjust the structure in the first direction to accommodate workpieces of different sizes. The structure can remain relatively rigid. For variability in another dimension, the interconnecting member can be an assembly of components whose mutual positions can be adjusted to adjust the dimension of the interconnecting member parallel to the second direction.

[0032] In an embodiment, at least one of the at least one clamping device is supported by said interconnecting member.

[0033] The interconnecting member is used to attach to the conveyor. Therefore, the load of the workpiece will be transmitted to the conveyor via the clamping device and the interconnecting member. The first member and the second member only need to bear the weight within a certain range. In addition, in embodiments in which the clamping device is only provided on one or both other sides of the area rather than on one side (seen in a direction perpendicular to the plane) where the first member and the second member are arranged, the shielding effect is not destroyed by the clamping device. Limiting the number of sides on which the clamping device is provided also simplifies the installation and removal of the workpiece to and from the device.

[0034] In an embodiment, the interconnection member includes a third member extending in the second direction, and the first member and the second member are connected to the third member at opposite ends of the third member.

[0035] In this embodiment, the structure is relatively simple and strong.The third member need not, and typically will not, be rod-shaped.

[0036] In an example of an embodiment in which at least one of the at least one clamping device is supported by the interconnecting component, the interconnecting component includes a third component extending in the second direction, and the first component and the second component are connected to the third component at opposite ends of the third component, and the clamping device supported by the interconnecting component is supported by the third component.

[0037] This further simplifies the interconnect components.

[0038] In an example of any embodiment in which at least one of the at least one clamping device is supported by the interconnecting member, the clamping device supported by the interconnecting member is journaled for movement in the first direction relative to the interconnecting member, and the device includes at least one biasing device for biasing the clamping device journaled for movement in the first direction away from the area.

[0039] The effect is to simplify the installation and removal of the workpiece, because the clamping device can be moved in a non-clamping configuration in a direction past the area of ​​the edge of the workpiece, grasp the workpiece and then release. For removal, the grip is released and the clamping device automatically moves away. In embodiments where the workpiece is grasped by the clamping device at the opposite edge, a relatively flexible workpiece can be held under tension to maintain its surface in a flat state and thus provide a more uniform surface treatment.

[0040] In an example of any embodiment in which at least one of the at least one clamping devices is supported by the interconnecting member, the clamping device supported by the interconnecting member is journaled for movement in the first direction relative to the interconnecting member, and the device includes at least one biasing device for biasing the clamping device journaled for movement in the first direction away from the area, a plurality of clamping devices are mounted to a single common supporting member journaled for movement in the first direction relative to the interconnecting member, and the at least one biasing device acts on the common supporting member.

[0041] This makes it easier to move all the clamping devices supported by the interconnected parts together and provide uniform stretching of the workpiece. In addition, there may be relatively many clamping devices and only a few biasing devices to save parts. The biasing devices may be pre-stretched. In this case, the level of pre-stretching may be adjustable. The biasing devices may include, for example, any type of elastic device (helical spring, leaf spring, elastomeric structure, etc.) or a gas spring.

[0042] In an embodiment of the device, the structure comprises a further interconnection member interconnecting the first member and the second member and located on a fourth side of the area.

[0043] This makes the structure more rigid and facilitates holding the first and second members in the correct positions with the correct orientation. In addition, the further interconnection member can be used to support other components of the device, such as one or more of the clamping devices. In general, the fourth side will be a side that is lower than the area, so that the further interconnection member is a lower interconnection member compared to the interconnection member on the third (opposite) side of the area, which is an upper interconnection member.

[0044] In an example of any embodiment in which the structure includes another interconnecting component interconnecting the first component and the second component and located on a fourth side of the area, the other interconnecting component is releasably connected to at least one of the first component and the second component by a corresponding fixing device, and the engagement position between the fixing device and the one of the first component and the second component involved is variable in the first direction.

[0045] In this embodiment, the dimensions of the device parallel to the first direction can be adjusted. This may be necessary to adapt the device to different types of troughs, different conveyor positions or workpieces with different sizes of corresponding dimensions.

[0046] In an example of any embodiment in which the structure includes another interconnecting component that interconnects the first component and the second component and is located on a fourth side of the region, the other interconnecting component includes another component extending in the second direction, and the first component and the second component are connected to the other component at opposite ends of the other component.

[0047] This makes the further interconnection component simpler. The device is particularly easier to handle, since the fourth side is typically the lower side and is therefore immersed in the tank close to the bottom of the tank. Straight components have less risk of colliding or getting stuck on components arranged at the bottom of the tank.

[0048] In the example of any embodiment wherein the structure comprises a further interconnecting member interconnecting the first and second members and located on a fourth side of the region, the further interconnecting member is provided with at least one driven member for engaging a guide defining a path through the slot in the second direction.

[0049] In particular, in an apparatus for electrochemical surface treatment of the workpiece, the guide helps the conveyor to keep the workpiece surface at a defined distance from the electrodes arranged in the tank of the apparatus. Furthermore, the conveyor and the components for attaching the interconnection component to the conveyor can be of a lighter construction without increasing the risk of rocking the device and the workpiece.

[0050] In the example of any embodiment wherein the structure comprises a further interconnecting member interconnecting the first member and the second member and located on a fourth side of the region, at least one of the clamping devices is supported by the further interconnecting member.

[0051] This helps limit movement, in particular oscillation, of the workpiece relative to the device. Furthermore, the workpiece can be stretched in the first direction. This allows the device to hold relatively thin and flexible workpieces, such as foils.

[0052] In an embodiment of the device, the first member and the second member are rod-shaped along at least a majority of their respective lengths.

[0053] In this embodiment, it is relatively easy to manipulate the workpiece relative to the device during installation and removal of the workpiece. There is a low risk that the workpiece will hit the first or second component. In addition, the shielding effect provided by the first component and the second component is relatively uniform in the first direction. The majority may comprise a central longitudinal section, so that only the end sections deviate from the rod shape, for example because fixing means or structures for engaging such means are provided at the longitudinal ends of the first component and the second component.

[0054] In an example of any embodiment in which the first member and the second member are rod-shaped along at least a majority of their respective lengths, the first member and the second member are circular-cylindrical along at least a majority of their respective lengths.

[0055] This helps improve the uniformity of the shielding effect because the flow of liquid through the first and second components is relatively smooth. There are fewer or no eddies. In addition, if the workpiece accidentally hits the first or second component during installation or removal, the risk of serious damage is reduced.

[0056] In an embodiment of the device, at least one surface of the first component and the second component is formed from an electrically insulating material along at least a majority of their respective lengths.

[0057] This makes the device particularly suitable for use in conjunction with equipment for electrochemical treatment (e.g. plating or etching). The first and second parts are not plated or weakened. They only provide a shielding effect that enhances the uniformity of the treatment of the workpiece surface at the edge region. The first and second parts can be made of an electrically insulating material (e.g. extruded or molded) in one piece, co-molded with an outer layer of electrically insulating material or provided with a sheath of such material.

[0058] In an embodiment of the device, at least one of the first and second members is the only member of the structure extending in the first direction from the interconnecting member by a distance that the member extends on the side of the area providing the member.

[0059] This ensures that the shielding effect between two consecutive devices is provided on one side of the gap between the edges of the workpiece by only one of the first part and the second part of one of the devices and on the other side of the gap by only one of the first part and the second part of the adjacent device. Structures that can interfere with the flow of liquid in an unpredictable way or with the electric field in an apparatus for electrochemical processing are avoided. In addition, the handling of the workpiece relative to the device during installation and removal is simplified. In particular, when the workpiece is in position between the first part and the second part and passes through the plane, a relative movement including a pivoting of the workpiece around an axis parallel to the longitudinal axis of the first part and the second part is made possible. Here, the term 'side' again refers to the viewing angle of an observer viewing the area in a direction perpendicular to the plane in which the clamping device is arranged to hold the workpiece.

[0060] In an embodiment of the device, the means for attaching the interconnection member to a conveyor is configured to attach the interconnection member to an overhead conveyor to suspend the device from the overhead conveyor.

[0061] Thus, the device need not include components for transporting the device through the tank at a position where it may be immersed in the liquid of the tank of the apparatus for wet chemical treatment. Lifting and lowering can be achieved by changing the level of the conveyor arrangement rather than by including the necessary components in the device.

[0062] According to another aspect, the system according to the invention for conveying planar workpieces is characterized in that, as seen in a second direction, the longitudinal axis of the leading one of the first and second parts of a first one of the workpiece holding devices and the longitudinal axis of the following one of the first and second parts of a next one of the workpiece holding devices in the second direction are offset relative to the corresponding planes of these workpiece holding devices in opposite directions perpendicular to said planes, so that the leading part of the first workpiece holding device and the following part of the next workpiece holding device at least partially face each other.

[0063] In an embodiment of the system, the workpiece holding device is a device according to the invention. However, in another embodiment of the system, in each workpiece holding device, the first component and the second component are arranged on the same side of the plane.

[0064] Thus, the system provides the same shielding effect for edge regions of the workpieces that follow each other in the second direction. The leading one of the first and second parts of the first workpiece holding device and the trailing one of the first and second parts of the next workpiece holding device at least partially face each other across a gap between a leading edge of a workpiece held by the first workpiece holding device and a trailing edge of the workpiece held by the second workpiece holding device. The first and second parts will typically have corresponding shapes and sizes to achieve good uniformity of the flow field across both surfaces of the workpiece.

[0065] In an embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, in each workpiece holding device, the structure comprises an interconnecting component interconnecting the first component and the second component on a third side of the area, the interconnecting component being releasably connected to at least one of the first component and the second component by a corresponding fixing device, and the engaging position between the fixing device and the one of the first component and the second component concerned is variable in a first direction.

[0066] This provides a simple way of adjusting the structure in the first direction to accommodate workpieces of different sizes. The structure can remain relatively rigid. For variability in another dimension, the interconnecting member can be an assembly of components whose mutual positions can be adjusted to adjust the dimension of the interconnecting member parallel to the second direction.

[0067] For another dimensional variability, the interconnection member may be an assembly of members whose mutual positions are adjustable to adjust the dimension of the interconnection member parallel to the second direction.

[0068] In an example of any embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, in each workpiece holding device, the structure includes an interconnecting component interconnecting the first component and the second component on a third side of the area, and at least one of the at least one clamping device is supported by the interconnecting component.

[0069] The interconnecting member is used to attach to a conveyor. Therefore, the load of the workpiece will be transmitted to the conveyor via the clamping device and the interconnecting member. The first member and the second member only need to bear the weight within a certain range. In addition, in embodiments in which the clamping device is only provided on one or both other sides of the area rather than on one side (seen in a direction perpendicular to the plane) where the first member and the second member are arranged, the shielding effect is not destroyed by the clamping device. Limiting the number of sides on which the clamping device is provided also simplifies the installation and removal of the workpiece to and from the device.

[0070] In an example of any embodiment of the system, wherein in each workpiece holding device, the first component and the second component are disposed on the same side of the plane, in each workpiece holding device, the structure includes a third component interconnecting the first component and the second component on a third side of the area, and the first component and the second component are connected to the third component at opposite ends of the third component.

[0071] In this embodiment, the structure is relatively simple and strong.The third member need not, and typically will not, be rod-shaped.

[0072] In an example of any embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, the structure includes an interconnecting component interconnecting the first component and the second component on a third side of the area, at least one of the at least one clamping device is supported by the interconnecting component, the structure includes a third component interconnecting the first component and the second component on the third side of the area, and the first component and the second component are connected to the third component at opposite ends of the third component, and the clamping device supported by the interconnecting component is supported by the third component.

[0073] This further simplifies the interconnection component.In this embodiment, the clamping device does not need to be mounted in a fixed position relative to the third component.

[0074] In an example of any embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, the structure includes an interconnecting component interconnecting the first component and the second component on a third side of the area, and at least one of the at least one clamping device is supported by the interconnecting component, the clamping device supported by the interconnecting component is journaled to move in the first direction relative to the interconnecting component, and the workpiece holding device includes at least one biasing device for biasing the journaled device to move away from the area in the first direction.

[0075] The effect is to simplify the installation and removal of the workpiece, because the clamping device can be moved in a non-clamping configuration in a direction past the area of ​​the edge of the workpiece, grasp the workpiece and then release. For removal, the grip is released and the clamping device automatically moves away. In embodiments where the workpiece is grasped by the clamping device at the opposite edge, a relatively flexible workpiece can be held under tension to maintain its surface in a flat state and thus provide a more uniform surface treatment.

[0076] In an example of any embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, the structure includes an interconnecting component interconnecting the first component and the second component on a third side of the area, at least one of the at least one clamping device is supported by the interconnecting component, the clamping device supported by the interconnecting component is journaled to move in the first direction relative to the interconnecting component, and the workpiece holding device includes at least one biasing device for biasing the clamping device journaled to move away from the area in the first direction, a plurality of clamping devices are mounted to a single common supporting component journaled to move in the first direction relative to the interconnecting component, and the at least one biasing device acts on the common supporting component.

[0077] This makes it easier to move all the clamping devices supported by the interconnected parts together and provide uniform stretching of the workpiece. In addition, there may be relatively many clamping devices and only a few biasing devices to save parts. The biasing devices may be pre-stretched. In this case, the level of pre-stretching may be adjustable. The biasing devices may include, for example, any type of elastic device (helical spring, leaf spring, elastomeric structure, etc.) or a gas spring.

[0078] In an example of any embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, in each workpiece holding device, the structure includes a first interconnecting component interconnecting the first component and the second component on a third side of the area, and another interconnecting component interconnecting the first component and the second component on a fourth side of the area.

[0079] This makes the structure more rigid and facilitates holding the first and second members in the correct positions with the correct orientation.In addition, the further interconnecting member may be used to support other components of the device, such as one or more of the clamping devices.

[0080] In an example of any embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, the structure includes a first interconnecting component interconnecting the first component and the second component on a third side of the area, and another interconnecting component interconnecting the first component and the second component on a fourth side of the area, the other interconnecting component is releasably connected to at least one of the first component and the second component by a corresponding fixing device, and the engagement position between the fixing device and the one of the first component and the second component involved is variable in the first direction.

[0081] In this embodiment, the dimensions of the workpiece holding device parallel to the first direction can be adjusted. This may be necessary to adapt the workpiece holding device to different types of slots, different conveyor positions or workpieces with different sizes of corresponding dimensions.

[0082] In an example of any embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, the structure includes a first interconnecting component interconnecting the first component and the second component on a third side of the area and another interconnecting component interconnecting the first component and the second component on a fourth side of the area, the other interconnecting component includes another component extending in the second direction, and the first component and the second component are connected to the other component at opposite ends of the other component.

[0083] This makes the further interconnection component simpler. The workpiece holding device is in particular easier to handle, since the fourth side is typically the lower side and is therefore immersed in the tank close to the bottom of the tank. Straight components have less risk of colliding or getting stuck on components arranged at the bottom of the tank.

[0084] In an example of any embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, the structure includes a first interconnecting component interconnecting the first component and the second component on a third side of the area and another interconnecting component interconnecting the first component and the second component on a fourth side of the area, the other interconnecting component is provided with at least one driven component for engaging a guide defining a path through the slot in the second direction.

[0085] In particular, in an apparatus for electrochemical surface treatment of the workpiece, the guide helps the conveyor to keep the workpiece surface at a defined distance from the electrodes arranged in the tank of the apparatus. Furthermore, the conveyor and the components for attaching the interconnection component to the conveyor can be of a lighter construction without increasing the risk of wobbling the workpiece holding device and the workpiece.

[0086] In an example of any embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, the structure includes a first interconnecting component interconnecting the first component and the second component on a third side of the area and another interconnecting component interconnecting the first component and the second component on a fourth side of the area, and at least one of the clamping devices is supported by the another interconnecting component.

[0087] This helps to limit movement, in particular oscillation, of the workpiece relative to the workpiece holding device. Furthermore, the workpiece can be stretched in the first direction. This allows the workpiece holding device to hold relatively thin and flexible workpieces, such as foils.

[0088] In an embodiment of the system, wherein in each workpiece holding device the first member and the second member are arranged on the same side of the plane, in each workpiece holding device the first member and the second member are rod-shaped along at least a majority of their respective lengths.

[0089] In this embodiment, it is relatively easy to manipulate the workpiece relative to the workpiece holding device when installing and removing the workpiece. There is a low risk that the workpiece will hit the first or second component. In addition, the shielding effect provided by the first component and the second component is relatively uniform in the first direction. A large portion may comprise a central longitudinal section, so that only the end sections deviate from the rod shape, for example because fixing means or structures for engaging such means are provided at the longitudinal ends of the first component and the second component.

[0090] In an example of any embodiment of the system, wherein in each workpiece holding device, the first member and the second member are arranged on the same side of the plane and the first member and the second member are rod-shaped along at least most of their respective lengths, and the first member and the second member are circular-cylindrical along at least most of their respective lengths.

[0091] This helps improve the uniformity of the shielding effect because the flow of liquid through the first and second components is relatively smooth. There are fewer or no eddies. In addition, if the workpiece accidentally hits the first or second component during installation or removal, the risk of serious damage is reduced.

[0092] In an embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, in each workpiece holding device, at least one surface of the first component and the second component is formed of electrically insulating material along at least a majority of their respective lengths.

[0093] This makes the system particularly suitable for use in conjunction with an apparatus for electrochemical treatment, such as plating or etching. The first and second components are not plated or weakened. They merely provide a shielding effect that enhances the uniformity of the treatment of the workpiece surface at the edge region. The first and second components may be made in one piece from an electrically insulating material, such as extruded or moulded, co-moulded with an outer layer of electrically insulating material or provided with a sheath of such material.

[0094] In an embodiment of the system, wherein in each workpiece holding device, the first component and the second component are arranged on the same side of the plane, in each workpiece holding device, at least one of the first component and the second component is the only component of the structure that extends from the interconnecting component in the first direction by a distance that the component extends on the side of the area providing the component.

[0095] This ensures that the shielding effect between two consecutive workpiece holding devices is provided on one side of the gap between the edges of the workpieces by one of the first and second parts of one of the workpiece holding devices and on the other side of the gap by one of the first and second parts of the adjacent workpiece holding device. Structures that can interfere with the flow of liquids in an unpredictable manner or with the electric field in an apparatus for electrochemical processing are avoided. In addition, the handling of the workpiece relative to the workpiece holding device during installation and removal is simplified. In particular, when the workpiece is in position between the first and second parts and passes through the plane, a relative movement including a pivoting of the workpiece around an axis parallel to the longitudinal axis of the first and second parts is made possible. Here, the term "side" again refers to the viewing angle of an observer viewing the area in a direction perpendicular to the plane in which the clamping device is arranged to hold the workpiece.

[0096] Embodiments of the system further include at least one of a loading device for mounting a workpiece to one of the workpiece holding devices and a unloading device for removing a workpiece from one of the workpiece holding devices, the loading device including a manipulator for moving the workpiece and configured to move the workpiece to a position in a plane in which the first component and the second component at least partially overlap an edge region of the workpiece (seen in a direction perpendicular to the plane), and the unloading device including a manipulator for moving the workpiece and configured to move the workpiece out of the position in the plane in which the first component and the second component at least partially overlap an edge region of the workpiece (seen in a direction perpendicular to the plane), wherein the movement includes a pivoting component about a pivot axis parallel to the longitudinal axes of the first component and the second component.

[0097] In particular, in embodiments in which the workpiece holding device is a device according to the invention, wherein at least the longitudinal axes of the first and second parts are offset in opposite directions relative to the plane, the workpiece can be mounted to and / or removed from the workpiece holding device from one side without removing the workpiece holding device from the conveyor. The pivoting movement allows the workpiece to be moved around the longitudinal axes of the first and second parts, which might otherwise be in the way. It should be noted that the mounting device and the removal device can be one and the same device.

[0098] In an embodiment of the system, the conveyor is an overhead conveyor and the workpiece holding device is suspended from the overhead conveyor.

[0099] In this embodiment, it is relatively easy to ensure that the liquid flow field is similar on both sides of the workpiece because the workpiece is oriented vertically. The effect of gravity on the flow field on both sides is equal. In addition, the components of the conveyor do not need to be immersed in the liquid in the tank of the apparatus for wet chemical processing.

[0100] According to a further aspect, a device according to the invention for the wet-chemical processing of planar workpieces comprises at least one system according to the invention.

[0101] Wet chemical treatments may include cleaning, electroless plating, dipping and the like. The treatments may in particular include electrochemical treatments. In this case, the apparatus will include one or more electrodes arranged in a tank and at least one device for establishing a potential difference between one or both surfaces of the workpiece and the electrodes. At least one of the clamping devices of each workpiece holding device will then be arranged to electrically contact a surface of the workpiece and configured to be electrically connected to the device to establish a potential difference.

[0102] According to another aspect, the method according to the invention for conveying workpieces through a slot of an apparatus for wet-chemical processing of planar workpieces is characterized in that one of the first and second parts of a workpiece holding device in which the first workpiece is mounted and one of the first and second parts of a tool holding device in which the second workpiece is mounted face each other across a gap.

[0103] The method comprises the use of the system according to the invention. Likewise, the device and the system according to the invention may be adapted and / or configured to perform the method according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] The present invention will be explained in further detail with reference to the accompanying drawings, in which:

[0105] Figure 1 is a cross-sectional view through a plating tank in an apparatus for wet chemical processing of planar workpieces;

[0106] Figure 2 is a front view of a first workpiece holding device for holding a planar workpiece in a slot of an apparatus;

[0107] Figure 3 yes Figure 2 A side view of the workpiece holding device shown in FIG.

[0108] Figure 4 Yes Figure 2 and 3 A front view of a pair of workpiece holding devices shown in FIG.

[0109] Figure 5 yes Figure 4 A detailed top view of adjacent end regions of a pair of workpiece holding devices;

[0110] Figure 6 It does not have artifacts Figures 2 to 5 A perspective view of a lower region of a workpiece holding device in use;

[0111] Figure 7 It does not have artifacts Figure 6 A first perspective view of an upper region of a workpiece holding device in use;

[0112] Figure 8 It does not have artifacts Figure 6 and 7 A second perspective view of an upper region of a workpiece holding device;

[0113] Fig. 9 is corresponding to Figure 8 but with the view removed of the support member to which the clamping device is secured;

[0114] Fig.10 is a front view of a second workpiece holding device;

[0115] Fig.11 yes Fig.10 A perspective view of a lower area of ​​a workpiece holding device;

[0116] Fig.12 yes Fig.10 and 11 A side view of an upper region of a workpiece holding device;

[0117] Fig.13 yes Figures 10 to 12 A first perspective view of an upper region of a workpiece holding device;

[0118] Fig.14 yes Figures 10 to 13 A second perspective view of an upper region of a workpiece holding device; and

[0119] Fig.15A , B are schematic diagrams illustrating the main underlying conveying system including the first and second workpiece holding devices, respectively. DETAILED DESCRIPTION

[0120] In the following, two types of systems for conveying workpieces through one or more slots of an apparatus for wet chemical processing of planar workpieces will be described. The apparatus may be configured for electrochemical processing of workpieces, such as plating or etching, in particular, but the system is not limited to use in such types of apparatus. The apparatus may also or alternatively be configured to perform stripping, washing, degreasing, and the like.

[0121] Both systems comprise a plurality of workpiece holding devices (also referred to as jigs), and a conveyor to which the workpiece holding devices are connected. The conveyor is an overhead conveyor and the workpiece holding devices are suspended from the conveyor so that at least a lower region of the workpiece holding devices and the workpieces can be immersed in one or more equipment slots. The workpieces are conveyed through the slots in a substantially vertical orientation, moving in a direction parallel to the plane of the workpieces. At least when conveyed through the one or more slots, the workpiece holding devices and the workpieces are arranged closely together in the direction of movement, wherein the rear edge of one of the workpieces is only slightly higher than the leading edge of the lower workpiece. The gap between the leading edge and the trailing edge is shielded to one side by (only) one of the two workpiece holding devices and to the other by (only) the other of the two workpiece holding devices. The workpiece holding devices do not block the gap so that the edges can be close together. The shielding limits the amount of (fresh) processing liquid that flows through the workpieces in the region adjacent to the edge. In the first system, the workpiece holding devices are all identical, but the arrangement of the components that implement the shielding is asymmetrical relative to the plane in which the workpieces are located and transverse to its plane. The components are offset in opposite directions relative to the plane in which the workpieces lie. In a second system, the arrangement of the shielding components is identical for each workpiece holding device, but the sides of the shielding components face alternately in opposite directions during use.

[0122] Workpiece holding device 1 for the first system ( Figures 2 to 9 , Fig.15A ) comprises a plurality of upper clamping devices 2a to 2f for holding a planar workpiece 4 ( Figures 7 to 9 ) and a plurality of lower clamping devices 3a to 3f ( Figure 6 ). In the illustrated embodiment, there are an equal number of upper clamping devices 2a to 2f and lower clamping devices 3a to 3f. In alternative embodiments, their number may be different. In particular, there may be fewer lower clamping devices 3a to 3f. If the workpiece 4 is relatively hard or has a relatively large mass, the lower clamping devices 3a to 3f may even be omitted.

[0123] In the illustrated embodiment, at least some of the clamping devices 2a to 2f, 3a to 3f are electrically arranged to contact at least one (e.g. two) major surfaces of the workpiece 4. If the processing of the workpiece is to include electroplating, the processing equipment will be configured to apply a potential difference that causes one or more surfaces of the workpiece 4 to act as a cathode. Anodes 5a, 5b ( Figure 1 ) is arranged in a tank 6 of the apparatus. Spray bars 7a, 7b are arranged in the tank 6 to flood the workpiece 4 with the electrolyte solution.

[0124] In a typical electroplating apparatus, the surface of the workpiece 4 will be pre-coated with a (thin) layer of conductive material (e.g. by vapor deposition or the like). Therefore, the workpiece 4 will have entered the reservoir 6 when the surface of the workpiece 4 is in a conductive state. For this reason, in an embodiment, only the upper clamping device 2 may be electrically arranged to contact one or both main surfaces of the workpiece 4. In this embodiment, the lower clamping devices 3a to 3f only hold the workpiece 4.

[0125] By their position and configuration the clamping devices 2 a to 2 f , 3 a to 3 f define a plane in which the workpiece 4 will lie when held by the workpiece holding device 1 .

[0126] The workpiece holding device 1 comprises a structure surrounding a planar area 8 on at least three sides, from which the workpiece holding device 1 is perpendicular to the planar area 8. Figure 2 ) direction. However, since the first part 9 and the second part 10 included in the structure overlap the edge area of ​​the workpiece 4, the area 8 does not correspond to the complete area occupied by the workpiece 4. The first part 9 and the second part 10 are arranged on the first and second opposite sides of the area 8, perpendicular to the plane. The first part 9 and the second part 10 have respective longitudinal axes extending in a first direction z parallel to the plane. In use, this direction z corresponds to the vertical or perpendicular orientation of these longitudinal axes. In use, the movement is in a second direction x parallel to the plane and transverse to the first direction.

[0127] In the illustrated embodiment, the structure surrounding the area 8 on at least three sides, as seen perpendicularly to the plane, actually surrounds the area 8 on four sides, so that the area 8 appears to be framed. The structure comprises an upper interconnection member 11 and a lower (also referred to as another) interconnection member 12. The upper clamping devices 2a to 2f are supported by the upper interconnection member 11. The lower clamping devices 3a to 3f are supported by the lower interconnection member 12.

[0128] The first and second components 13, 14 ( Figure 7) is provided for attaching the upper interconnection member 11 to an overhead conveyor for transporting the workpiece holding device 1 in a second direction x. The first member 13 and the second member 14 for attaching the upper interconnection member 11 to the conveyor attach the workpiece holding device 1 to the conveyor so that the workpiece holding device 1 is suspended from the conveyor. In the illustrated embodiment, the first member 13 and the second member 14 for attaching the upper interconnection member 11 to the conveyor are hooks. Other types of attachments are conceivable and the number of such members may also be varied.

[0129] At least the longitudinal axes of the first part 9 and the second part 10 are offset in opposite directions perpendicular to the plane. These directions are also perpendicular to the first direction z and the second direction x. In the illustrated embodiment, the first part 9 and the second part 10 are completely offset relative to the plane. It can be a distance from the plane equal to at least half the thickness of the workpiece 4 that the workpiece holding device 1 (more specifically, the clamping devices 2a to 2f, 3a to 3f) is configured to hold. This can be a distance in millimeters, for example at least 1 mm, 2 mm or 5 mm.

[0130] In the illustrated embodiment, the upper interconnection member 11 comprises a third member 15 extending in the second direction x. The first member 9 and the second member 10 are connected to the third member 15 at opposite ends of the third member 15 by means of a first fixture 16 and a second fixture 17. In the illustrated embodiment, the first fixture 16 and the second fixture 17 are configured for releasably connecting the first member 9 and the second member 10, respectively, to the third member 15. The engagement position between the fixtures 16, 17 and the first member 9 and the second member 10, respectively, is variable in the first direction z (in this case, along the length of the first member 9 and the second member 10). Thus, the workpiece holding device 1 can accommodate workpieces 4 of different sizes within at least a certain range. In the illustrated embodiment, the first fixture 16 and the second fixture 17 are clamps. Alternatives that provide the same variability in the engagement position can be envisaged.

[0131] The upper clamping devices 2a to 2f can be mounted directly in a fixed position to the third component 15. In contrast, in the illustrated embodiment, the upper clamping devices 2a to 2f are mounted to the support member 18 in a fixed position relative to a single support member 18. The support member 18 is journaled to move in a first direction z relative to the third component 15. The biasing devices 19a to 19c bias the support member 18 and thus the upper clamping devices 2a to 2f away from the area 8 in the first direction z. In the illustrated embodiment, the biasing devices 19a to 19c act on the support member 18 and the third component 15. In the illustrated embodiment, the biasing devices 19a to 19c are helical tension springs. In other embodiments, for example, gas springs may be used. In the illustrated embodiment, the biasing devices 19a to 19c are pre-tensioned, and the pre-tensioning is adjustable.

[0132] The movably journalled support member 18 facilitates mounting of the workpiece 4 to the workpiece holding device 1. This effect is also caused by the biasing of the biasing means 19a to 19c and stretches the thin and flexible planar workpiece 4 in the first direction z.

[0133] The lower interconnection member 12 includes a fourth member 20 ( Figure 6 ). The first component 9 and the second component 10 are connected to the fourth component 20 at opposite ends of the fourth component 20. The first component 9 and the second component 10 may be welded or otherwise connected to the first mounting block 21 and the second mounting block 22 disposed on opposite sides of the fourth component 20 ( Figure 3 and 6 ) to define an offset relative to a plane in which the clamping devices 2a to 2f, 3a to 3f are configured to hold the workpiece 4.

[0134] The lower clamping devices 3a to 3f are mounted to the fourth member 20 in a fixed position by fasteners such as bolts or screws.

[0135] In other embodiments, the mounting blocks 21, 22 may be replaced by fixtures such as the first fixture 16 and the second fixture 17. Furthermore, the lower clamping devices 3a to 3f may be journalled for movement relative to the fourth member 20 in the first direction z and biased away from the region 8 in the first direction z.

[0136] In the illustrated embodiment, the first and second follower members 23, 24 in the form of guide rollers are mounted to the fourth member 20 and protrude outwardly from the fourth member 20 in the first direction z. The follower members 23, 24 and the guide 25 ( Figure 1 In addition to guide rollers, other types of driven components 23 , 24 for engaging the guide 25 are conceivable.

[0137] In the illustrated embodiment, the first part 9 and the second part 10 are cylindrical in shape with a circular cross section. Other cross-sectional shapes, such as square, are conceivable. The constant cross section over at least a section of the length at one end of the first part 9 and the second part 10 allows for a variable point of engagement with the first fixture 16 and the second fixture 17 used in the illustrated embodiment. During the installation of the workpiece 4 to the workpiece holding device 1 or the removal of the workpiece 4 from the workpiece holding device 1, if the workpiece 4 contacts the first part 9 or the second part 10, the circular cross-sectional shape allows deflection with little risk of damage. In addition, due to the movement of the workpiece holding device 1 in the second direction x, the flow of the process liquid over the surface of the workpiece 4 is small.

[0138] In other embodiments, such as embodiments that do not include the first fixing device 16 and the second fixing device 17, one or more end sections of the first component 9 and the second component 10 may deviate from the shape of the rod, and the central section that forms most of the length of the first component 9 and the second component 10 may be rod-shaped (e.g., circular-cylindrical).

[0139] For electrochemical processing purposes, at least one surface of the first component 9 and the second component 10 is formed of an electrically insulating material along at least a large part of their respective lengths. This includes a central cross section of each of the first component 9 and the second component 10. In one embodiment, the first component 9 and the second component 10 are made entirely of electrically insulating material. Alternatively, they may be made of a metal or metal alloy and provided with an electrically insulating sheath or coating over at least a large part of their respective lengths. In all embodiments, the first component 9 and the second component 10 may be tubular. This saves weight. In addition, a cable may be arranged in at least one of the first component 9 and the second component 10. This may be useful in embodiments in which the lower clamping device 3a to 3f is arranged to electrically contact one or two major surfaces of the workpiece 4. A similar effect may be achieved if one or both of the first component 9 and the second component 10 are provided with a conductive core and an electrically insulating cover layer.

[0140] In the embodiment comprising at least two workpiece holding devices 1a, 1b ( Figure 4 , 5 , 15A), the successive workpiece holding devices 1a, 1b are attached to the conveyor so that the leading edge 26 ( Fig.15A) and a gap between the trailing edge 27b of the workpiece 4b held by the downstream workpiece holding device 1b. The first part 9a of the upstream workpiece holding device 1a faces the second part 10b of the downstream workpiece holding device 1b across the gap. This is because the first part 9a and the second part 10b are offset in opposite directions perpendicular to the plane in which the workpiece holding devices 1a, 1b are configured to hold the respective workpiece 4a, 4b. The distances by which the first part 9a and the second part 10b are offset relative to the respective planes are at least substantially equal in the illustrated embodiment.

[0141] When a potential difference is applied between the anode 5a, 5b and the workpiece 4a, 4b, the first part 9a and the second part 10b facing each other across the gap between the leading edge 26a and the trailing edge 27b provide a shielding effect. The electric field lines 28a, 28b are deflected from the edge region of the workpiece 4a, 4b. The offset distance from the plane in which the workpiece 4a, 4b is held can be optimized for surface uniformity at the edge 26a, 27b.

[0142] In order to mount the workpiece 4 to the respective workpiece holding device 1 and to unload the workpiece 4 from the respective workpiece holding device 1, a loading and unloading device (not shown) is provided. Each includes a manipulator for moving the workpiece 4. The workpiece holding devices 1a, 1b can be moved further in the second direction x for mounting and unloading. The manipulator is configured to grip the workpiece 4 in the case of the mounting device and move the workpiece 4 into the mounting position relative to the workpiece holding device 1. Similarly, the manipulator of the unloading device is arranged to grip the workpiece 4 and move the workpiece 4 out of the mounting position relative to the workpiece holding device 1. At this time, the mounting device and the unloading device are positioned adjacent to the workpiece holding device 1 facing the plane in which the workpiece 4 is arranged to be held. Since the first component 9 and the second component 10 are offset in opposite directions, the workpiece 4 must only be moved around one of the first component 9 and the second component 10. This is performed by a screwing movement including a pivoting movement of the workpiece 4 around a pivot axis parallel to the longitudinal axis of the first component 9 and the second component 10. Thus, from the perspective of the mounting device or unloading device involved, one of the leading edge 26 and the trailing edge 27 of the workpiece 4 moves behind one of the first component 9 and the second component 10 that is located on the near side of the plane in which the workpiece 4 is held. This means that the workpiece holding device 1 can remain attached to the conveyor during mounting and unloading operations.

[0143] For the second workpiece holding device 29 ( Figures 10 to 14 , Fig. 15B ) in which every other workpiece holding device 29 must be pivoted 180° or the mounting and removal devices must be arranged on the opposite side of the path of the workpiece holding device 29 and operate on every other workpiece holding device 29.

[0144] The second workpiece holding device 29 includes a device for holding a planar workpiece 32 ( Fig. 15B ) of a plurality of upper clamping devices 30a to 30d ( Figures 12 to 14 ) and a plurality of lower clamping devices 31a to 31d ( Fig.11 ). In the illustrated embodiment, there are an equal number of upper clamping devices 30a-30d and lower clamping devices 31a-31d. In alternative embodiments, their number may be different. In particular, there may be fewer lower clamping devices 31a-31d. If the workpiece 32 is relatively hard or has a relatively large mass, the lower clamping devices 31a-31d may be omitted.

[0145] In the illustrated embodiment, at least some of the clamping devices 30 a - 30 d , 31 a - 31 d are electrically arranged to contact at least one (eg, two) major surfaces of the workpiece 32 .

[0146] By the position and configuration of the clamping devices 30 a - 30 d , 31 a - 31 d , the clamping devices 30 a - 30 d , 31 a - 31 d define a plane in which the workpiece 32 will lie when held by the workpiece holding device 29 .

[0147] The workpiece holding device 29 comprises a structure surrounding a planar area 33 on at least three sides, as seen perpendicularly to the planar area ( Fig.10 ). The area 33 does not correspond to the complete area occupied by the workpiece 32. When in use, the first part 34 and the second part 35 included in the structure overlap the edge area of ​​the workpiece 32.

[0148] The first part 34 and the second part 35 are arranged on first and second opposite sides of the area 33, as seen perpendicularly to the plane. The first part 34 and the second part 35 have respective longitudinal axes extending in a first direction z parallel to the plane, the direction z corresponding to the vertical or perpendicular orientation of these longitudinal axes in use. In use, the movement is in a second direction x parallel to the plane and transverse to the first direction.

[0149] In the illustrated embodiment, the structure surrounding the area 33 on at least three sides, as seen perpendicular to the plane, actually surrounds the area 33 on four sides, so that the area 33 appears to be framed. The structure comprises an upper interconnection member 36 and a lower (also referred to as another) interconnection member 37. The upper clamping devices 2a to d are supported by the upper interconnection member 36. The lower clamping devices 31a to d are supported by the lower interconnection member 37.

[0150] In the illustrated embodiment, the hanger arm 38 ( Fig.10) is attached to the upper interconnecting member 36. A hanger arm 38 is included in an overhead conveyor system for transporting the workpiece holding device 29 in the second direction x. The workpiece holding device 29 is suspended from the hanger arm 38. In an alternative embodiment, a hook such as the first part 13 and the second part 14 forming the workpiece holding device 1 used to attach the upper interconnecting member 11 of the first workpiece holding device 1 to the conveyor can be used to attach the second workpiece holding device 29 to the conveyor.

[0151] At least the longitudinal axes of the first part 34 and the second part 35 are offset relative to the plane in a direction perpendicular to the plane. This direction is also perpendicular to the first direction z and the second direction x. In contrast to the first workpiece holding device 1, the first part 34 and the second part 35 of any workpiece holding device 29 are offset in the same direction. They are therefore on the same side of the plane.

[0152] In the illustrated embodiment, the first and second members 34, 35 are fully offset relative to the plane. They may be spaced from the plane by a distance equal to at least half the thickness of the workpiece 32 that the workpiece holding device 29 (more specifically, the clamping devices 30a to 30d, 31a to 31d) are configured to hold. This may be a distance in millimeters, such as at least 1 mm, 2 mm, or 5 mm.

[0153] In the illustrated embodiment, the upper interconnection member 36 includes a third member 39 ( Fig.10 , 13 14). The first member 34 and the second member 35 are connected to the third member 39 at opposite ends of the third member 39 by a mounting plate (not shown in detail) to which the first member 34 and the second member 35 are fixed, for example, by welding. The mounting plate is fixed to the third member 39 by fasteners (not shown), such as screws. In an alternative embodiment, the first member 34 and the second member 35 may be welded or directly bonded to the third member 39. In yet another alternative embodiment, a fixing device such as the fixing devices 16, 17 of the first workpiece holding device 1 may be used to make the engagement position between the upper interconnecting member 36 and the first member 34 and the second member 35, respectively, variable in the first direction z.

[0154] The upper clamping devices 30a to 30d are mounted to the support member 40 ( Fig.13). The support member 40 is journaled to move in the first direction z relative to the third member 39. The biasing means 41a to 41c bias the support member 40 and thus the upper clamping means 30a to 30f away from the area 33 in the first direction z. In the illustrated embodiment, the biasing means 41a to 41c act on the support member 40 and the third member 39. In the illustrated embodiment, the biasing means 41a to 41c are helical tension springs. In other embodiments, for example, gas springs may be used. In the illustrated embodiment, the biasing means 41a to 41c are pre-tensioned and the pre-tensioning is adjustable.

[0155] The movably journalled support member 40 facilitates mounting of the workpiece 32 to the workpiece holding device 29. This effect is also caused by the biasing of the biasing devices 41a to 41c and stretches the thin and flexible planar workpiece 32 in the first direction z.

[0156] The lower interconnecting member 37 includes a fourth member 42 extending in the second direction x. The first member 34 and the second member 35 are connected to the fourth member 42 at opposite ends of the fourth member 42. The first member 34 and the second member 35 may be welded or otherwise joined to first and second mounting blocks mounted to the fourth member 42 to define an offset relative to a plane in which the clamping devices 30a to 30d, 31a to 31d are arranged to hold the workpiece 32.

[0157] The lower clamping devices 31a to 31d are mounted to the fourth member 42 in a fixed position by fasteners such as bolts or screws.

[0158] In other embodiments, the mounting block may be replaced by a fixing device such as the first fixing device 16 and the second fixing device 16 of the first workpiece holding device 1 .

[0159] In the illustrated embodiment, the first moving member 43 and the second driven member 44 ( Fig.10 , 11 ) is mounted to the fourth member 42 and protrudes outwardly from the fourth member 42 in the first direction z. The driven members 43, 44 and the guide 25 ( Figure 1 ) interaction. Furthermore, other types of driven components 43, 44 than guide rollers for engaging the guide 25 are conceivable.

[0160] In the illustrated embodiment, the first part 34 and the second part 35 are cylindrical in shape and have a circular cross section over at least a large part of their respective lengths. This covers the central section extending between the third part 39 and the fourth part 42. In particular, also in the cross section at one or both longitudinal ends of the first part 34 and the second part 35, other cross-sectional shapes such as square can be envisaged. During the installation of the workpiece 32 to the workpiece holding device 29 or the removal of the workpiece 32 from the workpiece holding device 29, if the workpiece 32 contacts the first or second part 34, 35, the circular cross-sectional shape allows deflection with almost no risk of damage. In addition, due to the movement of the workpiece holding device 29 in the second direction x, the flow of the processing liquid above the surface of the workpiece 32 is small. Other cross-sectional shapes are more suitable for fixing the ends of the first part 34 and the second part 35 to the third and fourth parts 39, 42.

[0161] For electrochemical processing purposes, at least one surface of the first and second components 34, 35 is formed of electrically insulating material along at least a majority of their respective lengths. This includes a central cross section of each of the first and second components 34, 35. In one embodiment, the first and second components 34, 35 are made entirely of electrically insulating material. Alternatively, they may be made of metal or a metal alloy and provided with an electrically insulating sheath or coating over at least a majority of their respective lengths. In all embodiments, the first and second components 34, 35 may be tubular. This saves weight. In addition, a cable may be arranged in at least one of the first and second components 34, 35. This may be useful in embodiments in which the lower clamping devices 31a to 31d are configured to electrically contact one or two major surfaces of the workpiece 32. A similar effect may be achieved if one or both of the first and second components 34, 35 are provided with a conductive core and an electrically insulating cover layer.

[0162] In the embodiment comprising two second workpiece holding devices 29 ( Fig. 15B ), the continuous workpiece holding device 29 is attached to the conveyor so that there is a gap between the leading edge 45 of the workpiece 32a held by the upstream workpiece holding device 29 and the trailing edge 46b of the workpiece 32b held by the downstream workpiece holding device 29. The first part 34a of the upstream workpiece holding device 29 faces the second part 35b of the downstream workpiece holding device 29 across the gap. This is because the two workpiece holding devices 29 face in opposite directions, so that the first part 34a and the second part 35b are offset in opposite directions perpendicular to the plane in which the workpiece holding devices 29 are arranged to hold the respective workpieces 32a, 32b. The distances by which the first part 34a and the second part 35b are offset relative to the respective planes are at least approximately equal in the illustrated embodiment.

[0163] When a potential difference is applied between the anode 5a, 5b and the workpiece 32a, 32b, the first part 34a and the second part 35b facing each other across the gap between the leading edge 45a and the trailing edge 46b provide a shielding effect. The electric field lines 47a, 47b are deflected from the edge region of the workpiece 32a, 32b. The offset distance from the plane in which the workpiece 32a, 32b is held can be optimized for surface uniformity at the edge 45a, 46b.

[0164] The invention is not limited to the above-described embodiments, which may vary within the scope of the appended claims. For example, the lower interconnection members 12, 37 may be omitted and the upper interconnection members 11, 36 may be formed as an assembly for holding the first member 9 and the second member 10; 34, 35 at a variable distance from each other in the second direction x. For example, the way to do this is disclosed in WO 2018 / 225535A1.

[0165] Explanation of symbols

[0166] 1: First workpiece holding device

[0167] 2a to f; 30a to d: Upper clamping device

[0168] 3a to f; 31a to d: Lower clamping device

[0169] 4;32: Workpiece

[0170] 5a,b: Anode

[0171] 6: Storage tank

[0172] 7a,b: Spray boom

[0173] 8;33: plane area

[0174] 9; 34: first component

[0175] 10; 35: Second component

[0176] 11; 36: upper interconnection component

[0177] 12; 37: Lower interconnection component

[0178] 13: For attaching to the first component of the conveyor

[0179] 14: For attaching to the second part of the conveyor

[0180] 15;39: Third component

[0181] 16: First Fixing Device

[0182] 17: Second Fixing Device

[0183] 18; 40: Support member

[0184] 19a to 19c; 41a to 41c: biasing device

[0185] 20; 42: fourth component

[0186] 21: First installation block

[0187] 22: Second installation block

[0188] 23; 43: first driven component

[0189] 24; 44: second driven member

[0190] 25: Guide

[0191] 26;45: front edge

[0192] 27b;46: trailing edge

[0193] 28a to d; 47a to d: electric field lines

[0194] 29: Second workpiece holding device

[0195] 38: Hanger arm.

Claims

1. A device for holding a planar workpiece (4) in a slot of an apparatus for wet-chemical treatment of the workpiece (4), the device comprising: at least one clamping device (2, 3) for holding the workpiece (4) in a plane; a structure which, viewed perpendicularly to said plane and in the absence of said workpiece, surrounds, on at least three sides, a region (8) of said plane, wherein the structure comprises a first part (9) and a second part (10) which are arranged on a first and a second side of the region (8) and have respective longitudinal axes extending in a first direction (z) parallel to the plane, and wherein the structure comprises an interconnecting member (11) interconnecting the first member (9) and the second member (10) on a third side of the region (8); and at least one member (13) for attaching the interconnection member (11) to a conveyor for transporting the device in a second direction (x) parallel to the plane and transverse to the first direction (z), characterized in that The longitudinal axis is offset relative to the plane in opposite directions perpendicular to the plane.

2. The device according to claim 1, wherein the interconnection member (11) is releasably connected to at least one of the first member (9) and the second member (10) by respective fixing means (16, 17), and The engagement position between the fixing device (16, 17) and the one of the first component (9) and the second component (10) is variable in the first direction (z).

3. The device according to claim 1 or 2, Wherein at least one of the at least one clamping device (2) is supported by the interconnection member (11).

4. The device according to any one of the preceding claims, wherein the interconnection member (11) comprises a third member (15) extending in the second direction (x), and The first component (9) and the second component (10) are connected to the third component (15) at opposite ends of the third component (15).

5. The device according to claim 3 and 4, The clamping device (2) supported by the interconnecting member (11) is supported by the third member (15).

6. The device according to claim 3 or 5, wherein the clamping device (2) supported by the interconnecting member (11) is journalled for movement in the first direction (z) relative to the interconnecting member (11), and The device comprises at least one biasing means (19a to 19c) for biasing the clamping means (2) journalled to move away from the region (8) in the first direction (z).

7. The device according to claim 6, wherein a plurality of clamping devices (2) are mounted to a single common support member (18) journalled for movement in said first direction (z) relative to said interconnecting member (11), and wherein said at least one biasing means (19a to 19c) acts on said common support member (18).

8. The device according to any one of the preceding claims, The structure comprises a further interconnecting member (12) interconnecting the first member (9) and the second member (10) and located on a fourth side of the region (8).

9. The device according to claim 8, Wherein at least one of the clamping devices (3) is supported by the further interconnecting member (12).

10. A system for conveying planar workpieces (4; 32) through a slot of an apparatus for wet-chemical treatment of said workpieces (4; 32), The system comprises a plurality of workpiece holding devices (1; 29), each workpiece holding device (1; 29) comprises: at least one clamping device (2, 3; 30, 31) for holding the workpiece (4; 32) in a plane; and a structure which, viewed perpendicularly to said plane and in the absence of said workpiece, surrounds, on at least three sides, a region (8) of said plane, wherein the structure comprises a first component (9; 34) and a second component (10; 35) which are arranged on a first and a second side of the area (8) and have respective longitudinal axes extending in a first direction (z) parallel to the plane, and wherein the system further comprises a conveyor for transporting the component holding device (1; 29) in a second direction (x) parallel to the plane and transverse to the first direction (z), characterized in that The longitudinal axis of the leading one of the first part (9; 34) and the second part (10; 35) of the first one of the workpiece holding devices (1; 29) and the longitudinal axis of the following one of the first part (9) and the second part (10) of the next one of the workpiece holding devices (1; 29) in the second direction (x) are offset relative to the corresponding planes of these workpiece holding devices (1; 29) in opposite directions perpendicular to the planes, so that the leading part (9, 10; 34, 35) of the first workpiece holding device (1; 29) and the following part (9, 10) of the next workpiece holding device (1; 29) at least partially face each other.

11. The system according to claim 10, The workpiece holding device (1) is a device according to any one of claims 1 to 9.

12. The system according to claim 10, in, In each workpiece holding device (29), the first component (34) and the second component (35) are arranged on the same side of the plane.

13. A system according to any one of claims 10 to 12, The conveyor is an overhead conveyor and the workpiece holding device (1; 29) is suspended from the overhead conveyor.

14. An apparatus for the wet-chemical treatment of planar workpieces (4; 32), comprising at least one system according to any one of claims 10 to 13.

15. A method for conveying planar workpieces (4; 32) through a slot of an apparatus for wet-chemical treatment of said workpieces, The workpiece (4; 32) is mounted on a corresponding workpiece holding device (1; 29), each workpiece holding device (1; 29) comprises: at least one clamping device (2, 3; 30, 31) for holding the workpiece (4; 32) in a plane; and a structure which, seen perpendicularly to said plane and in the absence of said workpiece, surrounds, on at least three sides, an area (8; 33) of said plane, wherein the structure comprises a first part (9; 34) and a second part (10; 35) which are arranged on a first and a second side of the area (8; 33) and have respective longitudinal axes extending in a first direction (z) parallel to the plane, wherein the workpiece holding device (1; 29) is transported in a second direction (x) parallel to the plane and transverse to the first direction (z) so that a rear edge (27; 46) of the first workpiece (4; 32) is separated from a front edge (26; 45) of the second workpiece (4; 32) by a gap, characterized in that The first workpiece (4; 32) is mounted via one of the first component (9; 34) and the second component (10; 35) of the workpiece holding device (1; 29) and the second workpiece (4) is mounted via one of the first component (9; 34) and the second component (10; 35) of the workpiece holding device (1; 29) so as to face each other across the gap.

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