DEVICE AND METHOD FOR TRANSPORTING AND SEPARATING BLANKS FROM A MATERIAL WEB

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to German Patent Application No. 102024123355.9, filed Aug. 15, 2024, the entirety of which is incorporated herein by reference.

DESCRIPTION

The invention relates to a device for transporting and separating blanks from a material web, comprising a vacuum cylinder for transporting the blanks, a vacuum transport cylinder arranged downstream thereof for further transporting the blanks, and a transfer level arranged further downstream for taking over the blanks from the vacuum transport cylinder.

The invention also relates to a method for transporting and separating blanks from a material web.

STATE OF THE ART

It is known to manufacture a membrane electrode assembly (MEA) or parts thereof for a fuel cell, an electrolysis cell or a redox flow cell (liquid battery) or membrane-based humidifiers from material webs. The MEA comprises a catalyst-coated membrane (CCM) with edge reinforcements or frames (rims) made of a more cost-effective and resistant material on one or both sides. For further expansion, two gas diffusion layers (GDL) can be attached to the outer sides of the MEA. The GDL can be attached in a process that includes the manufacture of the MEA, the CCM and the frame(s), or in a spatially and/or temporally separate process. In another embodiment, an MEA is provided comprising a membrane and two gas diffusion layers arranged thereon, wherein edge reinforcements or frames are attached to one or both sides of this MEA.

In order to position the individual components or blanks of the MEA in relation to each other and connect them, it is known in the prior art to punch individual components from roll material, place them on top of each other, and laminate them. For the MEA to work effectively, the components must be precisely aligned and positioned. It is also important to handle the components as gently as possible, as even small forces acting on catalyst-coated membranes, for example, can cause cracks in the microstructure of the coating.

Furthermore, it is known from the prior art to transport the components of the MEA on vacuum cylinders. The vacuum cylinders are equipped with a porous or perforated surface on their outer walls, through which vacuum is applied. In order to change the distance between components or blanks transported in the material flow on a vacuum cylinder, in particular to increase it, so that they can later be deposited individually and positioned on other components, the components are transferred from a slower rotating vacuum cylinder to a faster rotating vacuum cylinder. At the start of the transfer, a respective blank is mainly sucked in and held by the first vacuum cylinder. In a later phase of the transfer, the blank is mainly sucked in and held by the second vacuum cylinder. The further the transmission process continues, the more the balance of power shifts in favor of the next cylinder. At the point where the suction forces of the second cylinder predominate, the blank is pulled down against the remaining suction force of the first cylinder.

This causes slippage, which leads to position inaccuracy during transmission to the second cylinder. Furthermore, the acceleration process during the slip process cannot be precisely predicted, which also impairs positional accuracy. In the field of MEA manufacturing in particular, there are high demands on the accuracy of MEA components that need to be stacked on top of each other.

Another negative side effect is that forces act on the blanks during transfer, which causes elongation in slightly stretchable blanks, namely MEA components, especially the CCM. In other words: The second cylinder pulls at the front end of the blank, while the first cylinder holds the blank back.

The disadvantage of the known solution is therefore that, on the one hand, forces act on the components during transfer from the first to the second vacuum cylinder, which can impair or even damage or destroy them. On the other hand, unwanted slippage occurs between the components and the surfaces of the vacuum cylinders. Due to slippage, the components lose their defined position on the surface of the vacuum cylinders, which impairs subsequent precise positioning relative to other components.

Task

The purpose of the present invention is to provide a device for transporting and separating blanks from a material web and to describe a method for transporting and separating blanks from a material web, which enable the blanks to be transferred from a vacuum cylinder to a vacuum transport cylinder with as little slippage as possible and thus more gently and accurately, and which at least partially overcome the disadvantages of the prior art.

Technical Solution

This task is solved by a device for transporting and separating blanks from a material web as described and claimed below.

According to the invention, it was recognized as advantageous to provide a vacuum cylinder with a pivotable vacuum segment, which allows the effective vacuum region on a surface of the vacuum cylinder to be reduced.

The device is used to transport and separate blanks from a material web, in particular MEA components. The blanks may also be wound dressings, labels, film or membrane blanks, or similar items. The device has a vacuum cylinder for transporting the blanks, a vacuum transport cylinder arranged downstream of this (as viewed in the transport direction of the material web and the blanks) for further transporting the blanks, and a further downstream transfer level for taking over the blanks from the vacuum transport cylinder, as well as a control unit. Separating blanks means that they can be stored or transferred individually. If necessary, the distance between two consecutive blanks can also be increased, especially if the blanks are fed directly adjacent to each other without any distance to the vacuum cylinder.

According to the invention, the vacuum cylinder has a pivotable vacuum segment which extends over an angular range of the vacuum cylinder for applying vacuum to its outer surface. A rotary actuator is provided for rotating the vacuum segment during operation of the device. For this purpose, the rotary actuator is connected to the control unit via data transmission technology and can be controlled by it.

By rotating the angular range in particular around the axis of rotation of the vacuum cylinder, the duration of the vacuum acting on a particular blank can be determined relative to the angle of rotation of the vacuum cylinder. This makes it possible, for example, to ensure that the vacuum acting on a blank in the transfer region, i.e., in the roller gap between the vacuum cylinder and the vacuum transport cylinder, can be terminated sooner or later.

In particular, at least one movement profile for the rotary actuator is stored in the control unit. The movement profile includes values for timing control and the pivot angle of the pivot movement.

In an advantageous manner, the effective holding force on a blank or parts thereof can be influenced by rotating the vacuum segment during transfer from the vacuum cylinder to the vacuum transport cylinder.

In a further development of the device, the pivot axis of the vacuum segment lies in the axis of rotation of the vacuum cylinder. It is particularly advantageous if the vacuum segment extends over an angular range of 180-300° of the vacuum cylinder, especially from 250-290°. This ensures that a large part of the outer surface of the vacuum cylinder has an effective vacuum region. Nevertheless, there remains a sufficient region in which there is no vacuum and which can be used to assist in detaching a blank from the vacuum cylinder or to reduce the vacuum acting on a blank.

In a first embodiment of the device, the vacuum segment is formed by a sector, i.e., by a circular segment which is open towards the outer surface of the vacuum cylinder and is rotatably mounted inside the hollow vacuum cylinder. In one design, the sector has a chamber that is connected to a vacuum system via a rotary feedthrough in the axis of rotation of the vacuum cylinder, thereby supplying vacuum to bores, holes, or pores in the surface of the vacuum cylinder jacket.

According to a second embodiment, the vacuum cylinder has supply channels distributed evenly around its circumference, and the vacuum segment is formed by at least one control disc which can connect the supply channels to a vacuum system.

In this design, for example, axially extending supply channels may be arranged under the surface of the vacuum cylinder jacket, which have a fluid connection to the holes or pores in the jacket surface of the vacuum cylinder. One control disc or, if necessary, two control discs, which are arranged in a sealing manner on one or both end faces of the vacuum cylinder, close the supply channels or release them. The control discs can be designed so that they have kidney-shaped recesses on the inside, which are connected to a vacuum system on the outside. The at least one control disc with its vacuum-loaded kidney is rotatable around the common axis with the vacuum cylinder and can be adjusted from the outside using the rotary actuator.

In a possible further development of the device, at least the vacuum cylinder is equipped with its own independent controllable drive motor for its rotational drive, wherein the drive motor of the vacuum cylinder is connected to the control unit by means of data transmission technology for controlling the drive motor. The vacuum cylinder can be operated with a speed profile stored in the control unit. Speed profiles for the rotation of the vacuum cylinder are stored in the control unit or can be generated, i.e., calculated. The drive motor of the vacuum cylinder can be controlled so that the vacuum cylinder rotates with a speed profile with different rotational speeds. In other words: the vacuum cylinder is accelerated, decelerated, or briefly stopped during its rotation. This is a good way to control slippage when a blank is transferred from the vacuum cylinder to the vacuum transport cylinder and, if needed, to change the distance between two blanks before and after the transfer.

In a further development of the device according to the invention, it is equipped with a mechanism for feeding a material web for transporting a material web, with a punching cylinder and a counter-punching cylinder for punching blanks from the material web upstream of the vacuum cylinder and/or the vacuum transport cylinder. The punching cylinder is arranged on one side of the material web and the counter-punching cylinder on the other side of the material web in such a way that the material web can pass between them and be punched. Excerpts, i.e., blanks surrounded by a punch residue, are also referred to as blanks here. The material web feeding mechanism, the punching cylinder, and the counter-punching cylinder are each equipped with their own independent drive motor for rotational drive.

According to a first variant, the material web is at least single-layered and has a product layer without a carrier layer, and the vacuum cylinder is formed by the punching cylinder or the counter-punching cylinder. A product layer that is punched by a punching cylinder and a counter-punching cylinder can have several layers.

This variant has the advantage of enabling a particularly compact design of the device.

According to a second variant, the material web is multi-layered with at least one carrier layer and one product layer, and the device has a delamination unit for separating the carrier layer from the blanks fixed on the vacuum cylinder. Thanks to the carrier layer, particularly sensitive and/or unstable product layers can be transported and processed. A product layer that is punched by a punching cylinder and a counter-punching cylinder can have several layers.

In both versions, the device can have a mechanism for removing the punching residues and, if necessary, the carrier layer freed from the blanks.

In an advantageous further development of the device, at least the vacuum transport cylinder is equipped with an adhesion-optimized, i.e., adhesion-enhancing surface, such that the surface enables good adhesion of the blanks. This ensures adequate adhesion even if this is not already guaranteed by the material properties of the cylinder surface. The adhesion-enhancing surface ensures that slippage is prevented or at least reduced when the blanks are transferred from the vacuum cylinder to the vacuum transport cylinder. The blanks can thus be transferred without affecting their position.

The invention also relates to a method for transporting and separating blanks from a material web as described and claimed below, which can be carried out in particular on a device as described above.

The method is used to transport and separate blanks from a material web, in particular components of an MEA, with the following continuously repeating steps:

• • a) feeding a material web with blanks
  • b) transporting the blanks on a vacuum cylinder
  • c) transferring the blanks to a vacuum transport cylinder and
  • d) transporting the blanks on the vacuum transport cylinder
  • e) transferring the blanks to a transfer level, wherein
  • in step c) the effective vacuum region on a surface of the vacuum cylinder is reduced during the transfer of a respective blank.

In particular, a region of the vacuum cylinder located upstream and adjacent to the rolling gap of the vacuum cylinder and vacuum transport cylinder can be ventilated and freed from vacuum. The position of the vacuum region can be shifted, for example, as explained in more detail below.

In a particularly advantageous further development of the method, the vacuum cylinder has a vacuum segment which extends over an angular range of the vacuum cylinder in order to apply vacuum to its outer surface. During transfer of the blanks to a vacuum transport cylinder, the vacuum segment is pivoted against the direction of rotation of the vacuum cylinder.

Tests have shown that it is advantageous if the vacuum segment begins to pivot against the direction of rotation as soon as at least 20%, and in particular at least 40%, of the surface area of a respective blank has been transferred from the vacuum cylinder to the vacuum transport cylinder and is being held by the latter.

By rotating the vacuum segment, the adhesive effect of the vacuum on the rear part of the blank is weakened, thereby reducing the retaining forces. This prevents unnecessary stretching of the blanks during transfer. Limiting expansion is particularly important for sensitive materials such as membranes, which are used in fuel cell manufacturing. By transferring most of a blank before reducing the effective vacuum region, it is ensured in a beneficial manner that the blanks can be transferred in a position-accurate manner, do not lose their orientation, and still experience hardly any stretching.

In a further refinement of the method, the vacuum segment is pivoted in the direction of rotation before each subsequent blank is transferred from the vacuum cylinder to the vacuum transport cylinder. The vacuum segment is therefore swung back to its original position. This ensures that a subsequent blank can be securely sucked onto the vacuum cylinder over its entire length and, in particular, in the region of its front edge. The pivot speed of the vacuum segment during return can correspond to the rotational speed of the vacuum cylinder, meaning that the vacuum segment and vacuum cylinder are both moved synchronously. Before a subsequent blank reaches the rolling gap, the surface of the vacuum cylinder in the transfer region is again evacuated.

In a further development of the method, the vacuum cylinder is equipped with a speed profile which is operated such that, at the start of the transfer of a respective blank, the vacuum cylinder and vacuum transport cylinder rotate at the same surface speeds, i.e., when the front edge of a respective blank reaches the transfer region, i.e., the roller gap between the vacuum cylinder and vacuum transport cylinder. This can also be referred to as synchronous operation of vacuum cylinders and vacuum transport cylinders.

The rotating of the vacuum segment and the speed profile of the vacuum cylinder interact in a suitable manner so that, at the start of the transfer of a respective blank from the vacuum cylinder to the vacuum transport cylinder, a blank is held by vacuum over its entire surface, a reduction in the vacuum in the vacuum cylinder in the rear region of the blank only occurs and the blank is released from the vacuum cylinder as soon as the front region of the blank is sufficiently fixed to the vacuum transport cylinder. In other words, by superimposing the movement profile of the vacuum segment's pivot movement and the speed profile of the vacuum cylinder's rotation, an even more precise, slip-free, and gentle transfer can be achieved.

This method can be combined with the method described in DE 10 2024 122 364, to which reference is hereby made in full.

In accordance with DE 10 2024 122 364, the rotational speed of the vacuum cylinder is temporarily reduced during the transfer of a respective blank from the vacuum cylinder to the vacuum transport cylinder.

The speed profile can also be designed such that the rotational speed of the vacuum cylinder is reduced as soon as at least 50%, in particular at least 65%, of the surface area of a respective blank has been transferred from the vacuum cylinder to the vacuum transport cylinder and is held by the latter.

It is particularly advantageous if the vacuum transport cylinder is moved at a primarily constant rotational speed, as this facilitates particularly precise transfer and positioning of the blanks in the downstream transfer level.

If the circulating conveyor belt located at the transfer level or the product web located at the transfer level moves at a constant speed equal to that of the vacuum transport cylinder, the blanks can be deposited with high positional accuracy.

Constant speed does not mean that the speed is unchangeable. Rather, it means that the speed does not change permanently in the regular operation, i.e., there is hardly any acceleration or deceleration, enabling a continuous manufacturing process. If, for example, the speed of the circulating conveyor belt or the product web located in the transfer level is to be increased with the aim of achieving a higher output, or if, for example, due to a necessary roll change or a temporarily slower upstream production plant, the speeds of the circulating conveyor belt or the product web located in the transfer level are to be reduced the speeds of the other elements of the device, i.e., vacuum cylinders, vacuum transfer cylinders, etc., must be adjusted accordingly.

The invention described and the advantageous further developments of the invention described also represent advantageous further developments of the invention in combination with each other, insofar as this is technically feasible.

With regard to further advantages and advantageous designs of the invention in terms of construction and function, reference is made to the subclaims and the description of exemplary embodiments with reference to the accompanying figures.

EXEMPLARY EMBODIMENT

The invention will be explained in more detail with reference to the accompanying figures. Corresponding elements and components are marked with the same reference symbols in the figures. For the sake of clarity, the figures are not shown to scale.

The following diagram shows

FIG. 1 a first embodiment of a device for transporting and separating blanks

FIGS. 2a and b a second embodiment of a device for transporting and separating blanks of a single-layer material web with two sub-variants

FIG. 3 a third embodiment of a device for transporting and separating blanks from a multi-layer material web

FIG. 4 a,b,c a detailed view of the vacuum cylinder and the vacuum transport cylinder at different points in time

FIG. 5 a blank in a top view

FIG. 6 a,b two embodiments of a vacuum segment.

FIG. 1 shows a first embodiment of a device 100 for transporting a material web 1000 consisting of blanks 1010 arranged in a row and serves to separate the blanks 1010. The device 100 is equipped with a material web feeding mechanism 1 for transporting the material web 1000, a vacuum cylinder 8 for transporting the blanks 1010, a vacuum transport cylinder 7 arranged downstream thereof (as viewed in the transport direction T) for further transporting the blanks 1010, and a transfer level E further downstream for taking over the blanks 1010 from the vacuum transport cylinder 7. Only individual blanks 1010 are shown as examples in the figures.

In transfer level E, a product web 2000 is guided and transported to receive the blanks 1010 from the vacuum transport cylinder 7.

FIGS. 2a and b show a second embodiment of a device for transporting and separating blanks from a single-layer material web 1000 in two variants a) and b).

The device 100 is equipped with a punching cylinder 2 and a counter-punching cylinder 3 for punching blanks 1010 from the material web 1000, which are arranged upstream of the vacuum transport cylinder 7. The vacuum cylinder 8 is formed by the counter-punching cylinder 3 in variant a) and by the punching cylinder 2 in variant b) and has its own independent drive motor (not shown). For clarity, a material web feeding mechanism 1 is not shown here or in the figure below. Downstream of the punching cylinder 2, a mechanism 5 is arranged for removing the punching residues 1020.

In transfer level E, a product web 2000 is guided and transported to receive the blanks 1010 from the vacuum transport cylinder 7.

FIG. 3 shows a third embodiment of a device 100 for transporting and separating blanks, which is similar in design to the device 100 shown in FIG. 2. In contrast, the material web 1000 is multi-layered with at least one carrier layer 1030 and one product layer 1040. Downstream of the punching cylinder 2, the device has a delamination unit 4 for separating the blanks 1010 from the carrier layer 1030.

Furthermore, a mechanism 5 is provided for removing the punching residues 1020 and the carrier layer 1030.

In further contrast to the embodiments described above, the transfer level E has a conveyor belt 6 for further transporting the blanks 1010.

FIGS. 4a-c show a detailed view of the vacuum cylinder and the vacuum transport cylinder over time.

Vacuum cylinder 8 and vacuum transport cylinder 7 can each be equipped with their own independent drive motor 84, so that vacuum cylinder 8 can be rotated with a speed profile with different rotational speeds R.

The vacuum cylinder 8 has an adjustable vacuum segment 82, by means of which the outer surface of the vacuum cylinder 8 is subjected to vacuum. The vacuum segment 82 is fluidically connected to a vacuum generator 83.

As indicated by the double arrows, the vacuum segment 82 can be pivoted in its position, i.e., rotated, but is not enlarged or reduced in size. The pivot movement is performed by a rotary actuator 85 controlled by the control unit 9.

Part of the device 100 is also a control unit 9, with which at least the drive motor 84 of the vacuum cylinder 8 and the rotary actuator 85 are connected by data transmission technology and can be controlled. Speed profiles for the rotation of the vacuum cylinder 8 and movement profiles for the rotating of the vacuum segment 82 are stored or can be generated in the control unit 9, which are dependent on the length 1013 and/or the area distribution over the length 1013 of a respective blank 1010. The movement profile imposed on the rotary actuator 85 also depends on the speed profile of the vacuum cylinder 8.

The vacuum segment 82 shown in the snapshot in FIG. 4a is in a non-deflected normal position. The blank 1010, which has just been transferred with its front edge 1014 to the vacuum transport cylinder 8, is held by vacuum on the vacuum cylinder 8 by the rolling gap over its entire length up to its rear edge 1012. This ensures that the blank 1010 can be transferred from the vacuum cylinder 8 to the vacuum transport cylinder 7 with positional accuracy.

FIG. 4b is a snapshot taken a little later. Vacuum cylinder 8 and vacuum transport cylinder 7 continued to rotate, transporting blank 1010 further. In order to reduce the effective vacuum area of the vacuum cylinder 7 and also reduce the holding force of the vacuum on the blank 1010, the vacuum segment 82 was pivoted against the direction of rotation R of the vacuum cylinder 8, as indicated by the arrows. In the region of the rolling gap between vacuum cylinder 8 and vacuum transport cylinder 7, the outer surface of vacuum cylinder 8 is ventilated and blank 1010 is not subjected to any vacuum-induced holding force here. This reduces the holding force acting on the rear region of the blank 1010, which makes it possible to slow down the vacuum cylinder 8 without causing the blank 1010 to shift during further transfer. Thanks to the speed reduction of the vacuum cylinder 8, which is achieved by applying a corresponding speed profile to the drive motor 84, the distance between two successive blanks 1010 can be increased.

As can be seen from the next snapshot in FIG. 4c, the distance between the blanks 1010 was increased. To ensure that the subsequent blank 1010 with its front edge 1011 is held securely by the vacuum cylinder 8 at the start of transfer to the vacuum transport cylinder 7, the vacuum segment 82 is swung back by a pivoting movement in the direction of rotation R of the vacuum cylinder 8, as indicated by two arrows. The pivot movement is effected by the rotary actuator 85, controlled by the control unit 9. The pivot movement can have the same rotational speed as the vacuum cylinder 8. The vacuum segment 82 is pivoted until it returns to its normal position (see FIG. 4a).

The movement sequence of vacuum segment 82 and vacuum cylinder 8, as outlined in FIGS. 4a-c, is repeated for each blank 1010.

The vacuum transport cylinder 7 is equipped with an adhesion-optimized surface 81 to improve the adhesion of the blanks 1010 and reduce slippage during transfer between the cylinders 7, 8.

FIG. 5 shows a blank 1010 in a top view with the dimensions of the blank 1010.

From the front edge 1011 to the rear edge 1012, a blank has a length 1013. The blank 1010 has a width of 1015. The area of the blank, as the product of length 1013 and width 1015, is marked with 1016. A subarea 1014, which occupies ⅓ of the front region of the blank 1010, i.e., more than 30% of its total area, is hatched for clarification.

FIGS. 6 a and b show two embodiments of a vacuum segment. In the embodiment shown in FIG. 6a, the vacuum segment 82 is formed by a hollow cylinder, a sector, which is open on one side on its outer surface and is rotatably mounted inside the vacuum cylinder 8. Where the hollow cylinder is open on its outer surface, a vacuum is provided on the outer surface of the vacuum cylinder 8. Where the hollow cylinder is closed on its outer surface, no vacuum is provided on the outer surface of the vacuum cylinder 8 and there is a region 86 without vacuum. The hollow cylinder can contain a chamber which is connected via a rotary feedthrough (not shown) in the rotational axis A of the vacuum cylinder 8 to a vacuum system and thus supplies boreholes or holes or pores in the jacket surface of the vacuum cylinder 8 with vacuum.

In the embodiment shown in FIG. 6b, the vacuum segment 82 is formed by a pivotable control disc, which is a connecting link between the vacuum cylinder 8 and a fixed disc 87 with a vacuum connection. The vacuum cylinder 8 is provided with supply channels running axially and evenly distributed around its circumference, which are indicated by a dotted line and which have a fluid connection to holes or pores in the outer surface of the vacuum cylinder 8. The control disc is used to connect the supply channels to a vacuum system.

The control disc closes or opens the supply channels. The control disc can be designed so that it has kidney-shaped recesses on its inner side (shown on the left in the illustration), which are connected to a vacuum system on the outer side (shown on the right in the illustration). The control disc with its vacuum-pressurized kidney is mounted so that it can pivot around the common axis A with the vacuum cylinder 8 and can be adjusted from the outside using a rotary actuator 85.

REFERENCE LIST

• • 1 material web feeding mechanism
  • 2 punching cylinders
  • 3 counter-punching cylinders
  • 4 delaminating unit
  • 5 removal mechanism
  • 6 conveyor belt
  • 7 vacuum transport cylinders
  • 8 vacuum cylinders
  • 81 surface vacuum (transport) cylinder
  • 82 pivotable vacuum segment (angular range)
  • 83 underpressure system/vacuum pump
  • 84 drive motor
  • 85 rotary actuator
  • 86 region without vacuum
  • 87 fixed disc with vacuum connection
  • 9 control unit
  • 100 device for transporting and separating
  • 1000 material web
  • 1010 blank from material web
  • 1011 front edge of the blank
  • 1012 rear edge of the blank
  • 1013 length of the blank
  • 1014 ⅓ of the area of the blank
  • 1015 width of the blank
  • 1016 area of the blank
  • 1020 punching residues
  • 1030 carrier layer
  • 1040 product layer
  • 2000 product web
  • A rotation axis
  • E transfer level
  • R rotation direction
  • E transfer level